MXPA06007241A - Isopeptide gap junction modulators. - Google Patents

Abstract

The invention relates to isopeptides capable of modulating intracellular gap junctional communication. The invention further relates to methods of using the isopeptides to maintain or enhance such communication. In one aspect, the isopeptides are antiarrhythmic isopeptides which target the same cells targeted by AAP, AAP10, HP5, and/or functional analogs thereof, i.e. the isopeptides are able to modulate the function of these cells by agonizing or antagonizing the function of AAP, AAP10, HP5, and/or functional analogs thereof.

Description

ISOPIPTIDE SPACE UNION MODULATORS Field of the Invention The invention relates to isopeptides capable of modulating intracellular junction communication. This invention further relates to methods for using the isopeptides to maintain or increase such communication.

BACKGROUND OF THE INVENTION There is an increased recognition that intracellular communication is essential for cell homeostasis, proliferation and differentiation. Such communication is considered to be facilitated by space junctions. These structures are taught that they are a route to attach cells and allow "cross-talk". See generalmene, Sperrelakis, N., (1989) Cell Interactions and Gap Junctions by N. Sperelakis, William C. Cole (Editor). Efforts have been made to understand the structure and function of space junctions. For example, it has been reported that such junctions are a type of complex formed between adjacent cells. Most space junctions are considered to consist of aggregate channels that directly link the interiors (cytoplasm) of neighboring cells. In adult mammals, space junctions are found in most cell types with Ref .: 173586 exception of circulating blood elements. More specifically, it is recognized that space junctions are specialized regions of the cell membrane with groups of hundreds to thousands of densely packed junction space channels (comprising two hemichannels or connexins). Many are considered to directly connect the cytoplasmic compartments of two neighboring cells. The space junction channel can be turned on between an open and a closed state. In the open state, ions and small molecules are considered to pass through the pore of the space junction channel. The conduction of electrical impulses and the intercellular dysfunction of signaling molecules takes place through the junctions of space. The "crosstalk" between junctions of space is referred to as intracellular space junction communication (GIJC). They are considered to play an important role in the regulation of cell metabolism, proliferation, cell-to-cell signaling, and tissue integrity. For example, GJIC is considered to allow rapid equilibrium of nutrients, ions, and fluids between cells. Space junctions are also considered to serve as electrical synapses in electrically excitable cells. In many tissues, electrical coupling is considered to allow faster cell-to-cell transmission of action potentials than chemical synapses. In cardiomyocytes and smooth muscle cells, for example, it is considered to assist in synchronous contraction. There are reports of other functions mediated by GJIC. For example, GJIC is considered to increase tissue responses to external stimuli. The second messengers are generally believed to be small enough to move from hormonally activated cells to quiescent cells through the binding channels and are activated later. Additionally, there are reports that space junctions can provide intercellular trajectories for chemical and / or electrical development signals and assist in defining the boundaries of development compartments. It has been described that GJIC occurs in specific patterns in embryonic cells and the deterioration of GJIC is related to the developmental abnormalities and the teratogenic effects of many chemicals. In addition, GJIC is considered to assist in the coordination of cellular activities. Some reports establish a link between abnormalities in GJIC and a range of disease states have been established both in vitro and in vivo. For example, it is considered to be a link between connexin abnormalities and heart disease. Several studies of the expression and distribution of Cx43 in hearts describe a reduced degree of Cx43 expression and a changed pattern of distribution for this space binding protein. See Kaprielian, R. R., et al. (1998) Circulation 97: 651-660; and Saffitz, J. E., et al., (1999) Cardiovasc Res. 42: 309-317. As a consequence, there is recognition in the field of relationships between a malfunction or absence of space junctions and an increased risk of arrhythmias. It is considered to be an additional relationship between the expression / distribution of altered connexin and chronic heart disease. There is an increased understanding that many of the antiarrhythmic peptides positively impact GJIC, often without affecting the duration or shape of the action potential. In addition, many such peptides are considered to lack undesirable proarrhythmic side effects. Such effects are considered to limit the use of many currently available antiarrhythmic drugs. On the other hand, the AAP, as well as certain derivatives of AAP, are considered to have some undesirable characteristics, for example, low stability and a need for high doses before reaching therapeutic efficacy. It would be desirable to have effective isopeptide modulators of GJIC. The present invention describes such isopeptides.

Brief Description of the Invention The invention generally relates to isopeptides that modulate intercellular space junction communication (CJIC). The invention has a wide range of useful applications including use in the treatment or prevention of pathologies associated with impaired GJIC. A preferred isopeptide according to the present invention is represented by the following general formula (I): where, if a is 1 then b is 0; if a is 0 then b is 1; x and y independently are 1-7; Ri is H or preferably H. R 2 is a side chain of any amino acid: for example, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline , serine, threonine, tryptophan, tyrosine, valine and sarcosine. Preferably R2 is a side chain of alanine or glycine. Preferably, R2 is the side chain of the amino acid glycine when a is 0 and b is 1, or alanine when a is 1 and b is 0; R3 is selected from the group consisting of H, NH2, NHR, NR2 / + NR3, OH, SH, RO, RS, RSO, RS02, COR, CSR, COOH, COOR, CONH2, CONHR, CONR2, OCOR, SCOR, ( R = alkyl, alkenyl, aryl, aralkyl, cycloalkyl, etc.). Preferably R3 is H or NH2; and R4 and R5 independently comprise a hydrophobic group, and preferably, they comprise a carbon ring, more preferably, they comprise a 6 or 12 membered aromatic carbon ring. In one aspect, the aromatic ring is substituted with at least one of: a lower alkyl, alkoxy, hydroxyl, carboxy, amine, thiol, hydrazide, amide, halide, hydroxyl, ether, amine, nitrile, imine, nitro, sulfide, sulfoxide, sulfone, thiol, aldehyde, keto, carboxy, ester, amide; which includes selenium and thio derivatives of the same. Optionally substituted rings also include sulfur, sulfoxide, sulfone, and thiol derivatives with, or without, a selenium group. Preferably the aromatic ring is substituted with at least one of: a lower alkyl, alkoxy, halide, nitrile and nitro group. More preferably, the aromatic ring is substituted with at least one of an alkoxy or nitro group. A lower alkyl group is preferably a methyl group. An alkoxy group is preferably a methoxy group. A halide group is preferably a chloride or fluoride group. A nitrile group is preferably a cyano group. In embodiments in which the aromatic carbon ring is substituted, such substitutions will typically list less than about 10 substitutions, more preferably, substitutions will list about 1 to 5, or 1 to 2 substitutions. The aromatic carbon ring can be selected from a benzyl, phenyl and naphthyl group, and is preferably a benzyl group. Preferably, R4 and R5 independently comprise a benzyl group substituted with at least one of a lower alkyl, alkoxy, halide, nitrile or nitro group. More preferably, R4 and R5 independently comprise a benzyl group substituted with at least one of a nitro or alkoxy group. A lower alkyl group is preferably a methyl group, an alkoxy group is preferably a methoxy group, a halide group is preferably a chloride or fluoride group, and a nitrile group is preferably a cyano group. The isopeptides of the invention can be represented by Formula I, where Ri is H, R2 is a side chain of an amino acid alanine or glycine, R3 is H or NH2, and R and Rs comprise a benzyl group substituted with at least one of a nitro or methoxy group. Preferably, when R2 is the amino acid glycine side chain, a is 0, b is 1 and Ri is H. Preferably, when R2 is the amino acid side chain alanine, a is 1, b is 0 and Ri is H.

Preferably, when a is 0 and b is 1, y is 4 and Rx is H. More preferably, when a is 0 and b is 1, y is 4, Rx is H and R5 comprises a benzyl group. Preferably, when a is 1 and b is 0, x is 1 or 2 and Ri is H. More preferably, when a is 1 and b is 0, x is 1 or 2, i is H and R4 comprises a benzyl group. When R2 is the amino acid side chain glycine is already 0, b is 1, preferably y is 4 and R is H. When R2 is the amino acid side chain alanine is already 1, b is 0, preferably x is 1 or 2 and Rx is H. Preferred isopeptides can be represented by Formula I where Rx is H; R2 is the side chain of the amino acid glycine when a is 0, b is 1 and y is 4, or alanine when a is 1, b is 0 and x is 1 or 2; R3 is H or NH2; and R and R5 comprise a benzyl group. In addition, the benzyl group is preferably substituted with a nitro or methoxy group. Such isopeptides may also comprise a peptide bond that is alkylated or otherwise modified to stabilize the isopeptide against enzymatic degradation and / or may comprise amino acids D, amino acid isoforms or a combination of amino acids D and amino acid isoforms. In another embodiment, the invention deals more specifically with isopeptides represented by the following general formula (II): where, if a = 1 then b = 0; if a = 0 then b = 1; x and y independently = 1-7; z = 1-6; q = 0-6; p = 0-1 Ri = H or CH3, preferably H. R2 = side chain of any amino acid: for example, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine , methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine and sarcosine. Preferably R2 is a side chain of alanine or glycine. Preferably, R2 is the side chain of the amino acid glycine when a is 0 and b is 1, or alanine when a is 1 and b is 0; R3 is selected from the group consisting of H, NH2, NHR, NR2, + NR3, OH, SH, RO, RS, RSO, RS02, COR, CSR, COOH, COOR, CONH2, CONHR, CONR2, OCOR, and SCOR, wherein R = alkyl, alkenyl, aryl, aralkyl, or cycloalkyl. Preferably R3 is H or NH2; and R6 and R7 are independently selected from the group consisting of H, alkyl, alkenyl, aryl, aralkyl, halogen, CN, N02, alkoxy, aryloxy, aralkyloxy, thioalkoxy, thioaryloxy, thioaralkyloxy, + S (CH3) 2, S03H, S02R , NH2, NHR, NR2, + NR3, OH, SH, COOH, COOR, CONH2, CONHR, CONR2, CH2OH, NCO, NCOR, NHOH, NHNH2, NHNRH, CH2OCOR, CH2OCSR, COR, CSR, CSOR, CF3, and CCI3 , and wherein R is alkyl, alkenyl, aryl, aralkyl, or cycloalkyl. Preferably, R6 and R are independently selected from the group consisting of H, alkyl, halogen, CN, N02, alkoxy, CF3. More preferably, R6 and R are independently selected from the group consisting of H, N02 and alkoxy. An alkyl is preferably methyl, a halogen is preferably chloro or fluoro, and an alkoxy is preferably methoxy. The isopeptides of the invention can be represented by Formula II, where Ri is H, R2 is a side chain of an alanine or glycine amino acid, R3 is H or NH2, and R6 and R7 are independently selected from the group consisting of H, N02 and methoxy. Preferably, when R2 is the amino acid side chain glycine, a is 0, b is 1 and Rx is H. Preferably, when R2 is the amino acid side chain alanine, a is 1, b is 0 and Ra is H. Preferably, when a is 0 and b is 1, y is 4 and Rx is H. More preferably, when a is 0 and b is 1, y is 4, p is 1, q is 0, and Ri is H. Preferably, when a is 1 and b is 0, x is 1 or 2 and Ri is H. More preferably, when a is 1 and b is 0, x is 1 or 2, z is 1, and Ri is H. When R2 is the amino acid glycine side chain it is 0 , b is 1, preferably y is 4 and Ri is H. When R2 is the side chain of the amino acid alanine it is already 1, b is 0, preferably x is 1 or 2 and Rx is H. The preferred isopeptides can be represented by the Formula II where Ri is H; R2 is the side chain of the amino acid glycine when a is 0, b is 1 and y is 4, p is 1, q is 0, or alanine when a is 1, b is 0 and x is 1 or 2, z is 1; R3 is H or NH2. In addition, R6 and R7 are independently selected from the group consisting of H, N02 and methoxy. The aromatic carbon ring preferably comprises a substituent in the 4-position. The substituent can be any group listed herein as one which can be a substituent of an aromatic ring. Preferably, the substituent is selected from the group consisting of: a lower alkyl, alkoxy, halide, nitrile and nitro group. Preferably the substituent is a nitro or alkoxy group.

An alkoxy group is preferably a methoxy group. In Formula II, when R6 or R7 is H, R7 or R6, respectively, it may be a nitro or methoxy group. The isopeptides of the invention can be represented by the general Formula II. The isopeptides of the invention may have the general form: H - first amino acid portion - second amino acid - OH portion. An "amino acid portion" is defined as a portion comprising an amino acid. An amino acid may be any amino acid, for example, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, Valine, and sarcosine. Such a portion may additionally comprise an additional chemical group or groups, for example a hydrophobic group, for example an aromatic carbon ring, for example, a 6-membered aromatic carbon ring. Included within the definition is a portion that does not comprise any additional chemical group, such that it consists of an amino acid, that is, the amino acid portion comprises an amino acid only, without the addition of additional chemical groups. An amino acid portion may comprise an amino acid selected from the group consisting of glycine, asparagine, glutamine, lysine, alanine and sarcosine. An amino acid portion may comprise an amino acid selected from the group consisting of glycine, asparagine, glutamine, lysine and alanine. An amino acid portion can be selected from the group consisting of glycine, glutamine, lysine and alanine. A first amino acid portion may comprise an amino acid selected from the group consisting of glycine, asparagine and glutamine. A second amino acid portion can be selected from the group consisting of lysine, alanine and sarcosine. Preferably, an amino acid of the first amino acid portion is glycine or glutamine. Preferably, an amino acid of the second amino acid portion is lysine or alanine. A first or second amino acid portion comprises an amino acid which may additionally comprise a hydrophobic group, for example an aromatic carbon ring, for example, a 6 or 12 membered aromatic carbon ring. The aromatic ring can be selected from a benzyl, benzoyl, phenyl or naphthyl group. Preferably, the aromatic ring is a benzyl or benzoyl group. Preferably, either the first amino acid portion or the second amino acid portion comprises an aromatic ring. Where a first amino acid portion comprises an aromatic ring, the aromatic ring is preferably a benzyl group. Where a second amino acid portion comprises an aromatic ring, the aromatic ring is preferably a benzoyl group. An aromatic ring can be substituted with at least one of: a lower alkyl, alkoxy, hydroxyl, carboxy, amine, thiol, hydrazide, amide, halide, hydroxyl, ether, amine, nitrile, imine, nitro, sulfide, sulfoxide, sulfone group , thiol, aldehyde, keto, carboxy, ester, an amide group; which includes selenium and thio derivatives thereof. The optionally substituted rings also include sulfur, sulfoxide, sulfone, and thiol derivatives with, or without, a selenium group. Preferably, an aromatic ring can be substituted with at least one of a lower alkyl, alkoxy, halide, nitrile group. and nitro, or it may be unsubstituted. More preferably, an aromatic ring is substituted with at least one of a nitro and alkoxy group. A lower alkyl group is preferably a methyl group. An alkoxy group is preferably a methoxy group. A halide group is preferably a chloride or fluoride group. A nitrile group is preferably a cyano group. An aromatic ring can be substituted with at least one of: H, alkyl, alkenyl, aryl, aralkyl, halogen, CN, N02, alkoxy, aryloxy, aralkyloxy, thioalkoxy, thioaryloxy, thioaralkyloxy, + S (CH3) 2, S03H, S02R , NH2, NHR, NR2, + NR3, OH, SH, COOH, COOR, C0NH2, CONHR, CONR2, CH20H, NCO, NCOR, NHOH, NHNRH, CH2OCOR, CH2OCSR, COR, CSR, CSOR, CF3, and CC13, and wherein R is alkyl, alkenyl, aryl, aralkyl, and cycloalkyl. Preferably, an aromatic ring can be substituted with at least one of: CN, N02 / alkoxy and CF3, or it can be unsubstituted. More preferably, an aromatic ring can be substituted with at least one of: N02 and alkoxy. An alkyl is preferably methyl, a halogen is preferably chloro or fluoro, and an alkoxy is preferably methoxy. Preferably, an aromatic ring can be substituted with at least one of a methyl, chloro, fluoro, trifluoromethyl, cyano, nitro and methoxy group, or it can be unsubstituted. More preferably, an aromatic ring can be substituted with at least one of a nitro and methoxy group. Preferably, an aromatic ring is substituted at position 4. Such isopeptides may comprise a peptide bond that is alkylated or otherwise modified to stabilize the isopeptide against enzymatic degradation and / or may comprise amino acids D, amino acid isoforms or a combination of D amino acids and amino acid isoforms. The first amino acid portion may comprise glycine or may comprise glutamine and an aromatic ring. The second amino acid portion may comprise alanine or may comprise lysine and an aromatic ring. Preferably, the first amino acid portion may comprise glycine or may comprise glutamine and an aromatic ring, and the second amino acid portion may comprise alanine or may comprise lysine and an aromatic ring. More preferably, the first amino acid portion may comprise glycine and the second amino acid portion may comprise lysine and an aromatic ring, or the first amino acid portion may comprise glutamine and an aromatic ring and the second amino acid portion may comprise alanine. Where the first amino acid portion comprises an aromatic ring, the aromatic ring is preferably substituted with a nitro or methoxy group, more preferably a methoxy group. Where the second amino acid portion comprises an aromatic ring, the aromatic ring is preferably substituted with a nitro or methoxy group. The isopeptides according to the invention have a wide variety of important uses and advantages. For example, the present isopeptides can be used to prevent or treat conditions associated with impaired space binding function resulting in reduced intracellular communication or poorly regulated cellular communication. In one aspect, the invention provides a method of administration to an individual having, or at risk of developing such a condition, a therapeutically effective amount of any of the isopeptides described above. Preferably, the administration is oral. In a preferred aspect, an individual is a human being. Preferably, the isopeptide is selected from the group consisting of the isopeptides shown in Table 2. Examples of conditions that can be treated include, but not limited to, cardiovascular disease, inflammation of the airway epithelium, alveolar tissue disorders, bladder incontinence, hearing impairment due to diseases of the cochlea, endothelial lesions, diabetic retinopathy and diabetic neuropathy, ischemia of the nervous system central and bone marrow, dental tissue disorders including periodontal disease, kidney disease, failure of bone marrow transplantation, wounds, erectile dysfunction, urinary bladder incontinence, neuropathic pain, subchronic and chronic inflammation, cancer and transplant failure. bone marrow and stem cell, conditions that occur during the transplantation of cells and tissues or during medical procedures such as surgery; as well as conditions caused by an excess of species reactive to oxygen and / or free radicals and / or nitric oxide. The invention further provides pharmaceutical compositions suitable for use in the methods described above, comprising any of the isopeptides described above and a pharmaceutically acceptable carrier. Preferably, the carrier is sterile, pyrogen-free and virus-free. In addition, the invention concerning the use of the isopeptides present for the manufacture of a medicament for the treatment of the above medical indications. Preferably, the isopeptide is selected from the group consisting of the isopeptides shown in Table 2.

Brief Description of the Figures Figures 1A-1B show exemplary synthesis schemes for generating isopeptides according to formula (I). Figures 2A-2B show exemplary synthesis schemes for generating isopeptides according to formula (II).

Detailed Description of the Invention As discussed, the invention relates to isopeptides that modulate intercellular space junction communication (CJIC). The invention has a broad spectrum of useful applications including use in the treatment or prevention of pathologies associated with impaired GJIC. The particular isopeptides of the invention are represented by Formula I above. The more specific isopeptides according to the invention are represented by the following General Formula II where, if a = 1 then b = 0; if a = 0 then b = 1; x and y independently = 1-7; z = 1-6; q = 0-6; p = 0-1 Rj = H or CH3, preferably H. R2 = side chain of any amino acid: for example, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine , methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, and sarcosine. Preferably R2 is a side chain of alanine or glycine. Preferably, R2 is the side chain of the amino acid glycine when a is 0 and b is 1, or alanine when a is 1 and b is 0; R3 is selected from the group consisting of H, NH2, NHR, NR2, + NR3, OH, SH, RO, RS, RSO, RS02, COR, CSR, COOH, COOR, CONH2, CONHR, CONR2, OCOR, and SCOR, wherein R = alkyl, alkenyl, aryl, aralkyl, or cycloalkyl. Preferably R3 is H or NH2; and R6 and R7 are independently selected from the group consisting of H, alkyl, alkenyl, aryl, aralkyl, halogen, CN, N02, alkoxy, aryloxy, aralkyloxy, thioalkoxy, thioaryloxy, thioaralkyloxy, + S (CH3) 2, S03H, S02R , NH2, NHR, NR2, + NR3, OH, SH, COOH, COOR, CONH2, CONHR, CONR2, CH2OH, NCO, NCOR, NHOH, NHNH2, NHNRH, CH2OCOR, CH2OCSR, COR, CSR, CSOR, CF3, and CC13 , and wherein R is alkyl, alkenyl, aryl, aralkyl, or cycloalkyl. Preferably, R6 and R7 are independently selected from the group consisting of H, alkyl, halogen, CN, N02, alkoxy, CF3. More preferably, R6 and R7 are independently selected from the group consisting of H, N02 and alkoxy. An alkyl is preferably methyl, a halogen is preferably chloro or fluoro, and an alkoxy is preferably methoxy. The isopeptides of the invention can be represented by Formula II, where Ri is H, R2 is a side chain of an alanine or glycine amino acid, R3 is H or NH2, and R6 and R7 are independently selected from the group consisting of H, N02 and methoxy. Preferably, when R2 is the glycine amino acid side chain, 'a is 0, b is 1 and Rx is H. Preferably, when R2 is the amino acid side chain alanine, a is 1, b is 0 and Rx is H. Preferably , when a is 0 and b is 1, y is 4 and Rx is H. More preferably, when a is 0 and b is 1, y is 4, p is 1, q is 0, and Ri is H. Preferably, when a is 1 and b is 0, x is 1 or 2 and Ri is H. More preferably, when a is 1 and b is 0, x is 1 or 2, z is 1, and Ri is H. When R2 is the glycine amino acid side chain it is 0 , b is 1, preferably y is 4 and Rx is H. When R2 is the amino acid side chain alanine is already 1, b is 0, preferably x is 1 or 2 and Rx is H. The preferred isopeptides can be represented by the Formula II where Rx is H; R2 is the side chain of the amino acid glycine when a is 0, b is 1 and y is 4, p is 1, q is 0, or alanine when a is 1, b is 0 and x is 1 or 2, z is 1; R3 is H or NH2. In addition, R6 and R are independently selected from the group consisting of H, N02 and methoxy. The aromatic carbon ring preferably comprises a substituent in the 4-position. The substituent can be any group listed herein as one which can be a substituent of an aromatic ring. Preferably, the substituent is selected from the group consisting of: a lower alkyl, alkoxy, halide, nitrile and nitro group. Preferably the substituent is a nitro or alkoxy group.

An alkoxy group is preferably a methoxy group. In Formula II, when R6 or R7 is H, R7 or R6 respectively, they may be a nitro or methoxy group. Particularly preferred isopeptides of the invention can be represented by Formula II where Rx is H; R2 is the side chain of the amino acid glycine; a is 0, b is 1 and y is 4, p is 1, q is 0; R3 is H or NH2; and R6 or R is H and R7 or Rg, respectively, is a nitro or methoxy group. Particularly preferred isopeptides of the invention can be represented by Formula II where Rx is H; R2 is the side chain of the amino acid alanine; a is 1, b is 0 and x is 1 or 2, z is 1; R3 is H or NH2; and R6 or R7 is H and R7 or Rs, respectively, is a methoxy group. The isopeptides of the invention can be represented by the general Formula II. The isopeptides of the invention may have the general form: H - first amino acid portion - second amino acid - OH portion. An "amino acid portion" is defined as a portion comprising an amino acid. An amino acid may be any amino acid, for example, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, Valine, and sarcosine. Such a portion may additionally comprise an additional chemical group or groups, for example a hydrophobic group, for example an aromatic carbon ring, for example, a 6 or 12 membered aromatic carbon ring. Included within the definition is a portion that does not comprise any additional chemical groups, such that it consists of an amino acid, that is, the amino acid portion comprising an amino acid only, without the addition of additional chemical groups. An amino acid portion may comprise an amino acid selected from the group consisting of glycine, asparagine, glutamine, lysine, alanine and sarcosine. An amino acid portion may comprise an amino acid selected from the group consisting of glycine, asparagine, glutamine, lysine and alanine. An amino acid portion can be selected from the group consisting of glycine, glutamine, lysine and alanine. A first amino acid portion may comprise an amino acid selected from the group consisting of glycine, asparagine and glutamine. A second amino acid portion can be selected from the group consisting of lysine, alanine and sarcosine. Preferably, an amino acid of the first amino acid portion is glycine or glutamine. Preferably, an amino acid of the second amino acid portion is lysine or alanine. A first or second amino acid portion comprising an amino acid may additionally comprise a hydrophobic group, for example an aromatic carbon ring, for example, a 6 or 12 member aromatic carbon ring. The aromatic ring can be selected from a benzyl, benzoyl, phenyl or naphthyl group. Preferably, the aromatic ring is a benzyl or benzoyl group. Preferably, either the first amino acid portion or the second amino acid portion comprises an aromatic ring. Where a first amino acid portion comprises an aromatic ring, the aromatic ring is preferably a benzyl group. Where a second amino acid portion comprises an aromatic ring, the aromatic ring is preferably a benzoyl group. An aromatic ring can be substituted with at least one of: a lower alkyl, alkoxy, hydroxyl, carboxy, amine, thiol, hydrazide, amide, halide, hydroxyl, ether, amine, nitrile, imine, nitro, sulfide, sulfoxide, sulfone, thiol, aldehyde, keto, carboxy, ester, an amide group; including derivatives of selenium and thio thereof. The optionally substituted rings also include sulfur, sulfoxide, sulfone, and thiol derivatives with, or without, a selenium group. Preferably, an aromatic ring can be substituted with at least one of a lower alkyl, alkoxy, halide, nitrile and nitro group, or it may be unsubstituted. More preferably, an aromatic ring is substituted with at least one of a nitro and alkoxy group. A lower alkyl group is preferably a methyl group. An alkoxy group is preferably a methoxy group. A halide group is preferably a chloride or fluoride group. A nitrile group is preferably a cyano group. An aromatic ring can be substituted with at least one of: H, alkyl, alkenyl, aryl, aralkyl, halogen, CN, N0, alkoxy, aryloxy, aralkyloxy, thioalkoxy, thioaryloxy, thioaralkyloxy, + S (CH3) 2, S03H, S02R , NH2, NHR, NR2, + NR3, OH, SH, COOH, COOR, CONH2, CONHR, CONR2, CH2OH, NCO, NCOR, NHOH, NHNH2, NHNRH, CH2OCOR, CH2OCSR, COR, CSR, CSOR, CF3, and CCl3 , and wherein R is alkyl, alkenyl, aryl, aralkyl, and cycloalkyl. Preferably, an aromatic ring can be substituted with at least one of: alkyl, halogen, CN, N02, alkoxy and CF3, or it can be unsubstituted. More preferably, an aromatic ring can be substituted with at least one of: N02 and alkoxy. An alkyl is preferably methyl, a halogen is preferably chloro or fluoro, and an alkoxy is preferably methoxy. Preferably, an aromatic ring can be substituted with at least one of: a methyl, chloro, fluoro, trifluoromethyl, cyano, nitro and methoxy group, or it can be unsubstituted. More preferably, an aromatic ring can be substituted with at least one of a nitro and methoxy group. Preferably, an aromatic ring is substituted at the 4-position.

Such isopeptides may comprise a peptide bond that is alkylated or otherwise modified to stabilize the isopeptide against enzymatic degradation and / or may comprise amino acids D, amino acid isoforms or a combination of amino acids D and amino acid isoforms. The first amino acid portion may comprise glycine, or may comprise glutamine and an aromatic ring. The second amino acid portion may comprise alanine, or may comprise lysine and an aromatic ring. Preferably, the first amino acid portion comprises glycine, or comprises glutamine and an aromatic ring, and the second amino acid portion comprises alanine, or comprises lysine and an aromatic ring. More preferably, the first amino acid portion comprises glycine and the second amino acid portion comprises lysine and an aromatic ring, or the first amino acid portion comprises glutamine and an aromatic ring and the second amino acid portion comprises alanine. Where the first amino acid portion comprises an aromatic ring, the aromatic ring is preferably substituted with a nitro or methoxy group, more preferably a methoxy group. Where the second amino acid portion comprises an aromatic ring, the aromatic ring is preferably substituted with a nitro or methoxy group. Preferred isopeptides can be represented by the general form: H - first amino acid portion - second amino acid - OH moiety, wherein the first amino acid portion comprises an amino acid selected from the group consisting of glycine, asparagine and glutamine; the second amino acid portion comprises an amino acid selected from the group consisting of lysine, alanine and sarcosine; the first or second amino acid portion comprises a 6-membered aromatic carbon ring. Preferably, the first amino acid portion may comprise an amino acid glycine or glutamine and the second amino acid portion may comprise an amino acid lysine or alanine. Where the first amino acid portion comprises a carbon ring, the amino acid is preferably glutamine. Preferably, the second amino acid portion comprises the amino acid alanine. Where the second amino acid portion comprises an aromatic carbon ring, the amino acid is preferably lysine. Preferably, the first amino acid portion comprises the amino acid glycine. Preferably the aromatic carbon ring is a benzyl or benzoyl group. Preferably the aromatic carbon ring is substituted with at least one of a lower alkyl, alkoxy, halide, nitrile and nitro group, more preferably substituted with at least one of an alkoxy and nitro group. Preferably, the aromatic carbon ring is substituted in the 4-position.

The isopeptides according to the invention have a wide variety of important uses and advantages. Particularly preferred isopeptides for methods, uses and compositions of the invention as described herein are those shown in Table 2. As discussed, the isopeptide may include a free N-terminus, or a free C-terminus, or both. Isopeptides within the scope of the present invention are frequently represented herein with free terminal N and / or terminal C group. These groups can be kept free for some uses of the invention. However, in another embodiment, the isopeptides may have blocked C-terminal groups and free N groups. Alternatively, such isopeptides may have blocked N groups and free C-terminal groups, or blocked C and N terminal groups. The more specific isopeptides within the scope of the invention and having the general Formula II and having the general form H - first amino acid portion - second amino acid - OH portion are shown in Table 1. The particularly preferred isopeptides of the invention and having the general Formula II and having the general form H - first amino acid portion - second amino acid - OH portion are shown in Table 2.

Table 1 Compound No. Name of compound 1 H-Gly-iso-Lys 4-nitrobenzoyl) -OH 2 H-Gly-iso-Lys 4-fluorobenzoyl) -OH 3 H-Gly-iso-Lys 4-cyanobenzoyl) -OH 4 H-Gly-iso-Lys 4-methoxybenzoyl) -OH H-Gly-iso-Lys 4 -chlorobenzoyl) -OH H-Gly-iso-Lys benzoyl) -OH 7 H-Gly-iso-Lys 4-phenoxybenzoyl) -OH 8 H-Gly-iso-Lys 4-t-butylbenzoyl) -OH 9 H-Gly-iso-Lys 4-n-butoxybenzoyl) -OH 10 H-Gly-iso-Lys 4-methylbenzoyl) -OH 11 H-Gly-iso-Lys 4-ethylbenzoyl) -OH 12 H-Gly-iso-Lys 4-n-butylbenzoyl) -OH 13 H-Gly-iso-Lys 4-n-hexylbenzoyl) -OH 14 H-Gly-iso-Lys 4-n-octylbenzoyl) -OH 15 H-Gly-iso-Lys 4-phenylbenzoyl) -OH 16 H-Gly-iso-Lys 4-benzyloxybenzoyl) -OH 17 H-Gly-iso-Lys 4-ethoxybenzoyl) -OH 18 H-Gly-D-iso-Lys (4-methoxybenzoyl) -OH 19 H-Gly-D-iso-Lys (4-nitrobenzoyl) -OH 20 H-Gly-D-iso-Lys (4-fluorobenzoyl) -OH 21 H-Gly-D-iso-Lys (4-cyanobenzoyl) -OH 22 H-Gly-D-iso-Lys (4-chlorobenzoyl) -OH 23 H-Gly-D-iso-Lys (benzoyl) -OH 24 H-Ala-iso-Lys (4-nitrobenzoyl) -OH 25 H-Val-iso-Lys (4-nitrobenzoyl) -OH 26 H-Ile- iso-Lys (4-nitrobenzoyl) -OH 27 H-Leu-iso-Lys (4-nitrobenzoyl) -OH 28 H-Phe-iso-Lys (4-nitrobenzoyl) -OH 29 H-Trp-iso-Lys (4 -nitrobenzoyl) -OH 30 H-His-iso-Lys (4-nitrobenzoyl) -OH 31 H-Tyr-iso-Lys (4-nitrobenzoyl) -OH 32 H-Ala-iso-Lys (4-methoxybenzoyl) -OH 33 H-Val-iso-Lys (4-methoxybenzoyl) -OH 34 H-Ile-iso-Lys (4-methoxybenzoyl) -OH 35 H-Leu-iso-Lys (4-methoxybenzoyl) -OH 36 H-Phe- iso-Lys (4-methoxybenzoyl) -OH 37 H-Trp-iso-Lys (4-methoxybenzoyl) -OH 38 H-His-iso-Lys (4-methoxybenzoyl) -OH 39 H-Tyr-iso-Lys (4 -methoxybenzoyl) -OH 40 H-Ala-D-iso-Lys (4-nitrobenzoyl) -OH 41 H-Val-D-iso-Lys (4-nitrobenzoyl) -OH 42 H-Ile-D-iso-Lys ( 4-nitrobenzoyl) -OH 43 H-Leu-D-iso-Lys (4-nitrobenzoyl) -OH 44 H-Phe-D-iso-Lys (4-nitrobenzoyl) -OH 45 H-Trp-D-iso-Lys (4-nitrobenzoyl) -OH 46 H-His-D-iso-Lys (4-nitrobenzoyl) -OH 47 H-Tyr-D-iso-Lys (4-nitrobenzoyl) -OH 48 H-Ala-D-iso- Lys (4-methoxyben) zoil) -OH 49 H-Val-D-iso-Lys (4-methoxybenzoyl) -OH 50 H-Ile-D-iso-Lys (-methoxybenzoyl) -OH 51 H-Leu-D-iso-Lys (4-methoxybenzoyl) -OH 52 H-Phe-D-iso-Lys (4-methoxybenzoyl) -OH 53 H-Trp-D-iso-Lys (4-methoxybenzoyl) -OH 54 H-His-D-iso-Lys (4-methoxybenzoyl) -OH 55 H-Tyr-D-iso-Lys (4-methoxybenzoyl) -OH 56 H-iso-Asn (NH (4- trifluoromethylbenzyl)) -Ala-OH 57 H-iso-Asn (NH (4-methoxybenzyl)) -Ala-OH 58 H-iso-Asn (NH (4-nitrobenzyl)) -Ala-OH 59 H-iso-Asn (NH (benzyl)) -Ala-OH 60 H-iso-Asn (NH (4-fluorobenzyl)) -Ala-OH 61 H-iso-Asn (NH (4-chlorobenzyl)) -Ala-OH 62 H-iso-Asn (NH (4-cyanobenzyl)) -Ala-OH 63 H-iso-Asn (NH (4-methylbenzyl)) -Ala-OH 64 H-iso-Asn (NH (4-n-butylbenzyl)) -Ala-OH 65 H-iso-Asn (NH (4-t-butylbenzyl)) -Ala-OH 66 H-iso-Asn (NH (4 -n-hexylbenzyl)) -Ala-OH 67 H-iso-Asn (NH (4-n-octylbenzyl)) -Ala-OH 68 H -iso-Asn (NH (4-phenylbenzyl)) -Ala-OH 69 H -iso-Asn (NH (4-phenoxybenzyl)) -Ala-OH 70 H-iso-Asn (NH (4-n-butoxybenzyl)) -Ala-OH 71 H-iso-Asn (NH (4-trifluoromethylbenzyl)) -D-Ala-OH 72 H-iso-Asn (NH (4-methoxybenzyl)) -D-Ala-OH 73 H-iso-Asn (NH (4-nitrobenzyl)) -D-Ala-OH 74 H-iso-Asn (NH (benzyl) )) -D-Ala-OH 75 H-iso-Asn (NH (4-fluorobenzyl)) -D-Ala-OH 76 H-iso-Asn (NH (4-chlorobenzyl)) -D-Ala-OH 77 H -iso-Asn (NH (4-cyanobenzyl)) -D-Ala-OH 78 H-iso-Asn (NH (4-methylbenzyl)) -D-Ala-OH 79 H-iso-Asn (NH (4-n -butylbenzyl)) -D- Ala-OH 80 H-iso-Asn (NH (4-t-butylbenzyl)) -D- Ala-OH 81 H-iso-Asn (NH (4-n-hexylbenzyl)) -D - Ala-OH 82 H-iso-Asn (NH (4-n-octylbenzyl)) -D- Ala-OH 83 H-iso-Asn (NH (4-phenylbenzyl)) -D-Ala-OH 84 H-iso -Asn (NH (4-phenoxybenzyl)) -D-Ala-OH 85 H-iso-Asn (NH (4-n-butoxybenzyl)) -D- Ala-OH 86 H-iso-D-Asn (NH (4 - trifluoromethylbenzyl)) -Ala-OH 87 H -iso-D-Asn (NH (4-methoxybenzyl)) -Ala-OH 88 H -iso-D-Asn (NH (4-nitrobenzyl)) -Ala-OH 89 H -iso-Asn (NH (4-methoxybenzyl)) -Sar-OH 90 H -iso-Asn (NH (-methoxybenzyl)) -Leu-OH 91 H-iso-Asn (NH (4-methoxybenzyl)) -Phe-OH 92 H-Gly-iso-Lys (2,4-dinitrobenzoyl) -OH 93 H-Gly-iso-Lys (2,4-dimethylbenzoyl) -OH 94 H-Gly-iso-Lys (2,5-dimethylbenzoyl) -OH 95 H-Gly-iso-Lys (3,5-dimethylbenzoyl) -OH 96 H-Gly-iso-Lys (2,4-dichlorobenzoyl) -OH 97 H-Gly-iso-Lys (2, 5-dichlorobenzoyl) -OH 98 H-Gly-iso-Lys (4-fluoro-3-nitrobenzoyl) -OH 99 H-Gly-iso-Lys (3-fluoro-4-methylbenzoyl) -OH 100 H-iso-Gln (NH (4-trifluoromethylbenzyl )) -Ala-OH 101 H -iso-Gln (NH (4-methoxybenzyl)) -Ala-OH 102 H-iso-Gln (NH (4-nitrobenzyl)) -Ala-OH 103 H-iso-Gln (NH (benzyl)) -Ala-OH 104 H-iso-Gln (NH (4-fluorobenzyl)) -Ala-OH 105 H-iso-Gln (NH (4-chlorobenzyl)) -Ala-OH 106 H-iso-Gln (NH (4-cyanobenzyl)) -Ala-OH 107 H-iso-Gln (NH (4-methylbenzyl)) -Ala-OH 108 H-iso-Gln (NH (4-n-butylbenzyl)) -Ala-OH 109 H-iso-Gln (NH (4-t-butylbenzyl)) -Ala-OH 110 H-iso-Gln (NH (4 -n-hexylbenzyl)) -Ala-OH 111 H-iso-Gln (NH (4-n-octylbenzyl)) -Ala-OH 112 H-iso-Gln (NH (4-phenylbenzyl)) -Ala-OH 113 H -iso-Gln (NH (4-phenoxybenzyl)) -Ala-OH 114 H-iso-Gln (NH (4-n-butoxybenzyl)) -Ala-OH 115 H-iso-Gln (NH (4-trifluoromethylbenzyl)) -D-Ala-OH 116 H-iso-Gln (NH (4 -methoxybenzyl)) -D-Ala-OH 117 H-iso-Gln (NH (4-nitrobenzyl)) -D-Ala-OH 118 H-iso-Gln (NH (benzyl)) -D-Ala-OH 119 H -iso-Gln (NH (4-fluorobenzyl)) -D-Ala-OH 120 H-iso-Gln (NH (4-chlorobenzyl)) -D-Ala-OH 121 H-iso-Gln (NH (4-cyanobenzyl) )) -D-Ala-OH 122 H-iso-Gln (NH (4-methylbenzyl)) -D-Ala-OH 123 H-iso-Gln (NH (4-n-butylbenzyl)) -D- Ala-OH 124 H-iso-Gln (NH (4-t-butylbenzyl)) -D- Ala-OH 125 H-iso-Gln (NH (4-n-hexylbenzyl)) -D- Ala-OH 126 H-iso-Gln (NH (4-n-octylbenzyl)) -D- Ala-OH 127 H-iso-Gln (NH (4-phenylbenzyl)) -D-Ala-OH 128 H-iso-Gln (NH (4-phenoxybenzyl)) -D-Ala- OH 129 H-iso-Gln (NH (4-n-butoxybenzyl)) -D- Ala-OH 130 H-iso-D-Gln (NH (4-trifluoromethylbenzyl)) -Ala-OH 131 H -iso-D-Gln (NH (4-methoxybenzyl)) -Ala-OH 132 H-iso-D-Gln (NH (4-nitrobenzyl)) -Ala-OH 133 H-iso-Gln (NH (4-methoxybenzyl) )) -Sar OH 134 H -iso-Gln (NH (4-methoxybenzyl)) -Leu-OH 135 H-iso-Gln (NH (4-methoxybenzyl)) -Phe-OH 136 H-Gly-iso-Orn (4-methoxybenzoyl) -OH 137 H-Gly-iso-Dab (4-methoxybenzoyl) -OH 138 H-Gly-iso-Dapa (4-methoxybenzoyl) -OH The more particular isopeptides according to the invention facilitate and / or maintain the intercellular communication mediated by the union of spaces. In one aspect, the isopeptides are antiarrhythmic isopeptides that direct the same cells directed by AAP, AAP10, HP5, and / or functional analogues thereof, that is, the isopeptides are capable of modulating the function of these cells by agonizing or antagonizing the function of AAP, AAP10, HP5, and / or functional analogues thereof. The mention of the AAPs known in the present context is to be seen as an example of the compounds that modulate the junction of space, which are compared with the isopeptides present. The scope of the present invention, however, is not limited to isopeptides having AAP agonist or antagonist properties. The invention also relates to the preparation and use of pharmaceutical compositions for the treatment of pathologies associated with impaired intercellular space junction communication and methods for using these compositions. Additional preferred isopeptides according to the invention show good activity in one or more of the following tests. Although orally available isopeptides are not necessarily identified as represented by Formulas I and II, above, they can be used to further confirm and optionally quantify the activity of one or a group of isopeptides. Accordingly, in one embodiment, the additionally preferred isopeptides exhibit binding, preferably specific binding, to a tissue, cell, or cell fraction referred to herein as a "standard AAP site binding assay". The test can optionally detect and quantify the binding of a subject peptide, for example, AAP, AAP10, HP5, or a functional analogue thereof. In a preferred embodiment, the isopeptide of the invention is a modulator of the function of such tissue, cell, or cell fraction (ie, the isopeptide agonizes or antagonizes the function of the antiarrhythmic peptide). In another embodiment, the isopeptide is a receptor modulator for the antiarrhythmic peptide (ie, the isopeptide is an agonist or receptor antagonists). The additionally preferred isopeptides according to Formulas I and II above show good function as a modulator of space junction communication (eg, as agonists or antagonists of AAP). In one aspect, the isopeptides function as an antiarrhythmic drug. Preferred agonist isopeptides of the invention provide an intracellular conductance (Gj) that is substantially the same as, or is greater than, the Gj of AAP in which it is referred to herein as a "standard cardiomyocyte assay". Preferred antagonist isopeptides provide a Gj that is lower (eg, at least about 10%, or at least about 20% less) than the Gj of AAP and / or block the ability of AAP to normalize the Gj of a cell ischemic, that is, returning the Gj to values substantially equal to those found in non-ischemic cells. Additionally, preferred isopeptides according to the invention increase the time for AV block in a mouse after infusion of CaCl 2, which is referred to herein as a "standard calcium-induced arrhythmia assay". Preferably, the isopeptides provide at least about 50% of the AAP activity, preferably at least about 70% of the AAP activity, more preferably substantially the same AAP activity (that is, it shows time delays of about the same duration). The isopeptides of the invention may additionally show reduction in the incidence of reentry of arrhythmias or in the size of an observed infarct zone which is referred to herein as a "standard ventricular reentry assay". Preferably, the isopeptides provide at least about 50% of the AAP activity, preferably at least about 70% of the AAP activity, more preferably substantially the same AAP activity in this assay (ie, it provides a similar reduction in the incidence or infarct zones of a similar or smaller size). Attempts have been made to improve the oral availability of certain compounds by increasing contact with an intestinal peptide transporter protein called PepTl. Much is known about the PepTl conveyor system. See Bailey, P.D., et al. (2000) Angew. Chem. Int. Ed. 39: 506; and references cited therein. In one aspect of the invention the potential oral availability of the present isopeptides can be examined. An empirical assay to validate the Bailey predictive assay described above is a "standard in vivo oral availability assay". In this assay, an isopeptide is orally administered to a mammal and blood samples taken over time. The concentration of the isopeptide is determined at different time intervals using standard protein quantification assays such as LC / MS / MS to calculate an area under the curve (AUC) of a batch of plasma protein concentration against time, using methods of routine known in the art. Preferably, different doses of isopeptides are administered to a plurality of animals in parallel to identify those isopeptides that show a dose-proportional increase in the maximum plasma and AUC concentration values. As a control, the same concentrations of the isopeptide can be administered intravenously and the area under AUC obtained for oral administration can be compared to the AUC obtained for intravenous administration. See, for example, Milo Gibal (1991) Biopharmaceutics and Pharmacology, 4th edition (Lea and Sediger). Isopeptides with good oral availability are those that are observed in the plasma with less than about 30 minutes after administration. Isopeptides that show good availability according to the standard in vivo oral availability assay described above may or may not be in substantial agreement with the Bailey assay. However for those isopeptides that do not show such agreement (and also for those that do), the isopeptides are observed in the plasma with less than about 30 minutes after oral administration as determined by the standard in vivo oral availability assay . A hPepTl binding assay can be performed as an initial exclusion separation for isopeptides which are then removed by exclusion in a standard in vivo oral availability assay and / or can be performed to confirm the results of a standard in vivo oral availability assay; however, the standard in vivo oral availability test provides the most important evidence of oral availability of isopeptide. The additionally preferred isopeptides as represented by Formula I and II above, exhibit a good half-life in accordance with what is referred to herein as an "in vitro plasma stability assay" or related phrase. Such isopeptides may be in substantial agreement with the above template model of PepTl substrate (Bailey assay). However, for some isopeptides that may or may not be in accordance with the model, the isopeptides which exhibit good stability in the assay have in one embodiment a half-life of more than about 48 hours, such as more than 24 hours, for example more than 12 hours, such as more than 6 hours, for example more than 3 hours, such as more than 1 hour, for example more than 30 minutes, such as more than 20 minutes, for example more than 15 minutes, such as more than 10 minutes, for example more than 5 minutes, such as more than 1 minute. In this embodiment, the isopeptides of the invention may show increased stability in the bloodstream.

Osteoporosis It will be understood that GJIC is important in the formation of bones. The additionally preferred isopeptides additionally, or alternatively, increase the activity of osteoblasts in what is referred to herein as a "standard osteoblast activity assay" which measures either the calcium wave formation and / or the alkaline phosphatase activity of osteoblast cells in the presence of isopeptides. Preferably, such isopeptides increase calcium wave activity, manifested as an increase in the number of cells involved in a wave (as determined by measuring intracellular Ca2 + levels using a calcium-sensitive fluorescent pigment, such as fura-2). and counts the number of cells that have fluorescence). The alkaline phosphatase activity can also be used to provide a measurement of osteoblast activity using standard colorimetric assays. The agonist isopeptides according to the invention provide at least about 10% of the AAP activity in such an assay, such as at least about 20% activity, for example at least about 30% activity, such as at least about 40% activity, for example at least about 50% of the AAP activity, preferably, at least about 70% activity, and still more preferably, 100% or greater activity of the AAP activity.

Cancer Preferred isopeptides according to the invention, alternatively, or additionally, reduce GJIC inhibition mediated by tumor promoters such as CTT, herein referred to as a "standard tumor promoter assay". Preferably, the isopeptides show reduction in GJIC inhibition, which are at least 50%, preferably 70%, and more preferably 100% or greater, than the reduction observed for AAP. As discussed, it is an object of the invention to provide isopeptides that modulate intercellular space junction communication (GJIC). In this manner, many isopeptides according to the invention may include one or more of the following characteristics: the ability to reduce cell non-coupling, to normalize the dispersion of the duration of the action potential, and to normalize the conduction velocity, the ability to control the cellular amount of space junctions that normalize (overregulated or down-regulated as necessary) expression of connexins; to normalize the degradation of space junctions (inhibit or increase), to normalize cellular connexin trafficking to the plasma membrane (increased or reduced); to facilitate the assembly of connexins in functional space junctions; to normalize the opening of existing gap junctions, eg, to induce or increase the aperture when they have been closed or door-locked by inhibitors (eg, such as by mediating or enhancing hyperphosphorylation of the cytoplasmic carboxy terminal domain of one or more connexins (for example, such as Cx43)) or closed of these when they open aberrantly (for example, as in Charcot-Marie-Tooth disease). Preferred isopeptides according to the invention, alternatively, or additionally, reduce the inhibition of GJIC mediated by tumor promoters such as DTT, herein referred to as a "standard tumor promoter assay". Preferably, the isopeptides show reduction in the inhibition of GJIC which are at least 50%, preferably 70% and more preferably 100% or greater, than the reductions observed by AAP. Particular assays useful for optionally identifying and quantifying the activity of preferred isopeptides of the invention are described below.

A. Standard Plasma Stability Assay The invention also provides isopeptides having increased stability in vitro or in vivo. In one aspect, the peptide comprises a peptide bond that is alkylated or otherwise modified to stabilize the peptide against enzymatic degradation. In another aspect, the peptide comprises one or more amino acids D. In a further aspect, the peptide has an increased stability in a standard stability assay. In one aspect, an in vitro plasma stability assay is performed as described in PCT / US02 / 05773, filed on February 22, 2002. As described in the application PCT / US02 / 05773, the peptides can be incubated in plasma or serum and samples are taken at regular intervals for analysis by CLAR or LC / MS / MS, to quantify the amount of non-degraded peptide. The appropriate conditions (column, solvent, gradient, and temperature) for such analyzes are estimated to ensure that the peptide peak and the plasma peaks do not have the same retention time. This is given by subsequent injections of a peptide, plasma, and coinjection with the peptide and plasma, followed by optimization of the CL method parameters until a satisfactory separation is obtained. The control plasma sample without the peptide, treated in the same way, can also be taken and evaluated. Samples may include, but are not limited to, a blank, the peptide at an appropriate concentration (eg, 0.1 mg / mL), plasma without peptide, one or more samples for t = 0, and one or more samples in each regular interval. Preferably, multiple samples are taken in parallel. The sample concentrations (peak height in mAU or ion counts) can be batch plotted against time and established as a function describing mono exponential decay (for example, using a standard Excel package). Preferably, the peptide according to the invention has a half-life of more than about 48 hours, such as more than 24 hours, for example more than 12 hours, such as more than 6 hours, for example more than 3 hours, such as more than 1 hour, for example more than 30 minutes as determined using this test. Plasma stability can be examined in vivo using standard assays. For example, isopeptides can be administered to the mammal, such as the rat, by bolus injections at volumes of about 1 ml / kg for both i.v. as p.o. Preferably, the isopeptides are tested in parallel with control samples such as a buffer solution or an antiarrhythmic peptide with a known stability. Blood samples are collected at different time periods (for example, at B.D. 5, 15, 30, 60, 90, 120, 180, and 240 minutes, where B.D refers to before the dose). The amounts of isopeptides in the samples can be quantified using routine methods in the art, such as LC / MS / MS. For example, the concentrations of isopeptides in the plasma samples can be calculated from ranges that cover the external standard curve of the peptide from 1.0 to 1000 nM. Plasma concentrations against time data can be used by pharmacokinetics placed in model in inNonLin 3.5 (Pharsight, Mountain View, CA) using non-compartmental analysis and the resulting parameters of AUC, Fpo, Clb, tl / 2, Cmax and tmax they can be determined as known in the art.

B. Standard Oral Availability Test It is a preferred aspect of the invention to provide isopeptides with increased in vivo availability. The absorption of isopeptides after oral administration is often limited because they are degraded by any of the enzymes in the gastrointestinal tract (Gl) or by enzymes in the intracellular lumen of the enterocytes. In addition, the physico-chemical properties of the isopeptides, especially if great potential for hydrogen bonding, make it difficult for these molecules to permeate the enterocytes by passive transcellular diffusion. The preferred isopeptides according to the invention are, therefore, isopeptides having affinity for a hPepTl transporter or an analog thereof. The three-dimensional conformation and key binding sites of the peptide compounds that bind the PepTl transporter are described by Bailey, PD, et al., 2000, supra, and the desired peptides can be modeled in silico 'to optimally configure within this site link, as described above (see, for example, Bailey, PD, et al., (2000), supra; Vinter, J.G., (1996) J. Comput. Aided Des. 10: 417). The oral availability of the peptide comprising the structure as shown in Formula I, Formula II, Table 1, or more generally identified using the Bailet assay, can be evaluated by its ability to bind to a PepTl transporter, preferably a hPepTl transporter.

For example, the PepTl cDNA, preferably a hPepTl cDNA (See, for example, Covitz, K. M., et al., (1996) Pharm. Res. 13 (11): 1631-34) can be expressed in an Xenopus oocyte expression system and the uptake of the tagged peptide into the oocyte can be monitored for approximate Ki values as described in Temple, C.S., et al. (1996) J. Physiol. (London) 494; 795; Meredith, D., et al., (1998) J. Physiol. (London) 512: 629. In one aspect of the invention, a standard in vivo oral availability assay is performed to determine the oral availability of an isopeptide that is modeled to optimally shape the Bailey substrate template, as discussed above. In this assay, an isopeptide is orally administered to a mammal, such as a rat, in an orally administrable form (eg, as part of a food pellet or in water), while at the same time, the same peptide concentration is administer iv (for example, through a catheter inserted into the vein and femoral artery). The isopeptides can be administered as bolus injections at concentrations ranging from 10"5-10" 10 in volumes of 1 ml / kg for both oral and i.v. The animals are given 500 I.U. of heparin i.v. 5 minutes before the first blood sample is taken. A control blood sample, "before the dose" or sample B.D., is collected approximately 5 minutes before the administration of the isopeptides. A sample of the dosing solution (eg, 100 μl of water comprising 10"5-10" 10 M of the peptide) is maintained for concentration determination. Blood samples are collected at t = B.D. 5, 15, 30, 60, 90, 120, 180, and 240 minutes.

Blood is collected in vial of EDTA stabilized blood sample frozen in labeled ice and stored on ice until rapidly centrifuged at 4 ° C for 5 minutes (10,000 x g). Plasma (100 μl) is harvested, transferred to a labeled polypropylene microcentrifuge vial (eg eppendorf 0.5 ml), frozen on ice and stored at -20 ° C until further analysis. Approximately 40 μl of the filtrate is injected onto a CLAR column (XterraMS C18, 3 x 50 mm, 3.5 μm particles) and eluted using a linear gradient from 0 to 100% B in 4.0 minutes. The column is washed for 2.9 minutes in buffer B (0.1% formic acid in acetonitrile or other appropriate buffer) and equilibrated for 5 minutes in buffer A (0.1% formic acid in water or other appropriate buffer) before the next injection of the sample. Mass spectrometry is performed using routine methods in the art and as further described below in Examples 1 and 2. The concentrations of compounds in the plasma samples are calculated from an external standard curve covering the range from 1.00 to 1000. nM. Plasma concentrations against time data are used for pharmacokinetic modeling in inNonLin 3.5 (Pharsigth, Mountain View, CA) using non-compartment analysis and AUC values are determined as known in the art. Preferably, the orally available isopeptides according to the invention are observed at significant levels in the plasma within about 30 minutes or less. The AUC values observed in animals receiving i.v. of the peptide are used to evaluate such effects as the release and half-life that should be the same in the two systems.

C. Standard Cardiomyocyte Assays In one aspect, an isopeptide according to the invention is administered to a cardiac cell and the function of space junction is evaluated. Optimal isopeptides for such procedures can be identified in standard cardiomyocyte assays. In one aspect, cardiac cells of a mammal, such as guinea pig hearts, are isolated by collagenase perfusion in accordance with the Langendorf method. The cells are exposed to the isopeptide and evaluated for GJIC by patch clam using methods known in the art. Intercellular conductance (Gj) using the formula: Where Ip, pulse and Ip, rest represent the current in the passive cell during the pulse and before the pulse respectively, and Up and Ua represent the passive and active cell voltage. The change in the Gj value during administration of the isopeptide is analyzed by comparing the relative changes in Gj. For example, the relative Gj as a function of the time before, and during, the stimulation with isopeptide (for example, about 10"8 M) can be determined.Preferably, the isopeptide provides a Gj, which is substantially equal to the Gj ( ± 10%) of an antiarrhythmic peptide such as AAP, AAP10, HP5, and functional analogues thereof In one aspect, the cell is an ischemic cell, and the isopeptide provides a Gj, which is substantially equal to that of a non-cell. ischemic (± 20%, preferably, ± 10%) Additional details concerning cardiomyocyte testing are provided in PCT / US02 / 05773, filed on February 22, 2002.

D. Standard Calcium-Induced Arrhythmia Assay Isopeptides suitable for administration to cardiac cells can be identified in an in vivo model of calcium-induced arrhythmias according to the model of Lynch et al. (1981) J Cardiovasc. Pharmacol. 3: 49-60. Mice (25-30 g) are anesthetized with a neurolept anesthetic combination and an i.v. cannula. It is inserted into the vein of the tail. A load ECG signal II is continuously recorded by placing stainless steel ECG electrodes on the right t member and the left rear leg. The buried electrode is placed in the right rear stop. The signal is amplified (x 5,000-10,000) and filtered (0.1-150 Hz) by means of a Hugo Sachs Electronic module 689 ECG module. The analog signal is digitized by means of a 12-bit data acquisition board (Data Translation model DT321) and placed on samples at 1000 Hz using the Notocord HEM 3.1 software for Windows NT. After a 10 minute equilibration period, the test sample of the peptide was injected into the tail vein. Mice previously treated with buffer solution are tested as a measure of the level of control in untreated animals. The injection volume is 100 μl in all experiments.

Infusion of CaC12 (30 mg / ml, 0.1 ml / min »100 mg / kg / min (calcium chloride-2 -hydrate, Riedel-de Haén, Germany)) is started 3 minutes after i.v. administration. of the drug or vehicle. The delay time for the start of 2nd degree AV block is determined as the time the start of the CaCl2 infusion until the first arrhythmic event occurs. A 2nd degree AV block event is defined as an intermittent failure of the AV condition characterized by a P wave without the concomitant QRS complex. The responses are expressed in relation to the time until 2nd grade AV block occurs in mice treated with vehicle. The maximum effect of the compounds (eg, isopeptides, AAP, AAP10 or controls) is determined. Preferably, the isopeptides according to the invention have antiarrhythmic activity compared to the compounds AAP, AAP10, HP5, or a functional analogue thereof, that is, the peptides increase the time for an AV block in a mouse after the infusion of CaCl2. Preferably, the isopeptides provide at least about 40% of the AAP activity, for example at least about 50% of the AAP activity, such as about 60% of the AAP activity, for example at least about 70% of the AAP activity, such as at least about 80% of the AAP activity, for example at least about 90% of the AAP activity, for example at least about substantially the same AAP activity, such as about 110% of the AAP activity, for example at least about 120% of the AAP activity, such as at least about 130% of the AAP activity, for example at least about 140% of the AAP activity, such as about 150% of the AAP activity, for example at least about 160% of the AAP activity, such as at least about 170% of the AAP activity, for example at least about 180% of the AAP activity, preferably at least about 190% of the AAP activity, more preferably at least about 200 or greater% of the activity of AAP (ie, the p eptides show time delays of approximately the same duration as that induced by AAP).

E. Standard Osteoblast Activity Assay The intercellular communication modulation represents a mechanism by which osteotropic factors regulate the activity of the cells that make up the bones. Therefore, in one aspect, the isopeptides according to the invention are used to increase the activity of osteoblasts by increasing the space binding communication between bone cells, thereby increasing bone formation in vivo. The efficacy of an isopeptide according to the invention can be preliminarily evaluated in human osteblast cells (hOB), for example by measuring calcium wave activity and / or alkaline phosphatase activity. In one aspect, cells are isolated from the human bone marrow obtained by pricking the posterior iliac spine of healthy volunteers (aged 20-36): 10-15 ml of marrow material was collected in 15 ml of PBS + Ca, Mg (Life Technologies, Cat. No. 14040) with 100 U / ml heparin (Sigma, Cat. No. H-3149). The mononuclear fraction of the marrow is isolated in a lymphoprep gradient (Nycomed Pharma, Cat. No. 1001967), by centrifugation at 2200 rpm for 30 minutes. After harvesting, the mononuclear fraction is washed once with culture medium and centrifuged at 1800 rpm for 10 minutes. Subsequently the cells are counted and placed in culture medium at 5x106 cells / 100 mm plate. The hOB medium (all reagents are obtained from Life Technologies): MEM w / o Red Phenol w / Glutamax (Cat. No. 041-93013) supplemented with 10% heat-inactivated fetal calf serum (Cat. No. 10106 ) and 0.1% penicillin / streptomycin (Cat. No. 15140). The medium was changed the next day and the cells were cultured at 37 ° C in 5% C02 with medium change every 7 days. After 4-6 weeks of culture, the cells reach 70% confluence. The medium is then supplemented with 100 nM Dexamethasone (Sigma, Cat. No. D-4902) for 7 days. The cells are then placed for video imaging experiments: a # 1 glass slide of 25 mm is placed in a 35 mm dish (or each well of a 6-well multiple dish), the cells are placed at 2.5 xl05 cells / slide and cultured for 2-3 days before use. ROS 17 / 2.8 cells are grown in 100 mm dishes at 37 ° C with 5% C02 and the medium is changed every 2-3 days. Half ROS (all reagents are obtained from Life Technologies); MEM (Car. No. 31095) is supplemented with 10% heat-inactivated calf serum (Cat. No. 16170), 1% NEAA (Cat. No. 11140), 1% sodium pyruvate (Cat. 11360), L-Glutamine 1%) Cat. No. 25030) and 0.1% penicillin / streptomycin (Cat. No. 15140). For video imaging experiments, cells on sliding covers are plated at 2-3x10-5 cells / slide cover and cultured for 2-3 days before use. Cells grown on slide covers are loaded onto 5μM of fura-2-AM (Molecular Probes, Cat. No. F-1221), for 30 minutes at 37 ° C, and incubated in fresh medium for 20 minutes. The sliding covers are then fixed in a PDMI-2 culture chamber (Medical Systems Corp.), maintained at 37 ° C with superfused C02, in a Zeiss Axiovert microscope, intercellular calcium waves are induced by mechanical stimulation of a single cell at use a borosilicate glass micropipette attached to an Eppendorf 5171 micromanipulator. Imaging is carried out using a MetaMorph imaging system (Universal Imaging). The excitation light (340 and 380 nm) is provided by a monochromator (T.I.L.L. Photonics GmbH). The images are acquired with an intensified CCD camera (Dage MTI) and digitized with a Matrox MVP image processing board. The number of cells involved in the calcium wave in the presence and absence of peptide, can be used to provide a measure of the increase in GJIC.

In one aspect, administration of an isopeptide increases the number of cells involved in a wave at least about twice as compared to cells that have been exposed to a control, such as a buffer. In another aspect, administration of an isopeptide decreases the number of cells involved in a wave by at least about two times. The agonist isopeptides according to the invention provide at least about 10% of the AAP activity in such an assay, such as at least about 20% activity, for example, at least about 30% activity, such as less about 40% activity, for example at least about 50% AAP activity, preferably, at least about 70% activity, and still more preferably, 100% or more activity activity of AAP. The cells can also be measured by the presence of alkaline phosphatase activity to provide a general measure of osteoblast activity. In one aspect, the cells are plated in 96 well plates at a concentration of 8000 cells / well (hOB) or 3000 cells / well (ROS) in a normal culture medium of 200 μl. On day 4 (or day 3 for ROS cells), cells are washed with 200 μl of MEM, 0.1% BSA (Sigma, Cat.No. A-9418). Samples that comprise a suitable medium (eg, 200 μl MEM, 0.1% BSA) contain various concentrations of peptides, control, AAP or AAP10 are added to the cells, and the culture continues for about 4 days (2 days for ROS cells). Around day 8 (preferably day 5 for ROS cells), cells were assayed by alkaline phosphatase using an alkaline phosphatase assay (ALP) as is known in the art. ALP assays are generally colorimetric end-point methods for measuring enzyme activity, and can be carried out using an alkaline phosphatase kit (Sigma, Cat. No. 104-LL). Preferably, the cells are washed once with 200 μl of PBS + Ca, Mg, 100 μl alkaline buffer is added to each well and the cells are incubated at 37 ° C for 10 minutes. Subsequently, 100 μl of substrate solution was added to each well and the plate was incubated at 37 ° C for 30 min. 100 μl of 2.0N NaOH was added to each well to stop the reaction. Absorbance is measured using a plate reader at 405 nm. The agonist isopeptides according to the invention provide at least about a 5% increase in the production of the alkaline phosphatase relative to the isotonic saline solution, preferably at least an increase of about 10% in the production of phosphatase alkaline in relation to the isotonic saline solution, and still more preferably an increase of 15% or more in the production of alkaline phosphatase relative to the isotonic saline solution. The increase in alkaline phosphatase production is a measure of the increased activity of osteoblasts and thus a measure of an increase in bone formation.

F. Standard Tumor Promoter Assay Compound 1, 1-bis (p-chlorophenyl) -2, 2, 2-trichloroethane, also known as the DDT insecticide, is an inhibitor of space junction communication, and has capabilities tumor promoters, inhibits cell-to-cell communication by reducing the number and size of space junctions, and exposure to DDT is associated with decreased cellular levels of phosphorylated (active) forms of the Cx43 space-binding protein. These actions are considered pivotal for the oncogenic properties of the compound (X. Guan, et al., (1996) Carcinogenesis, 17 1791-1798, R. J. Ruch, et al., (1994) Carcinogenesis, 15 301-306); B. V. Madhukar, et al., (1996) Cancer Lett. 106 117-123). As a means of monitoring the therapeutic efficacy of isopeptides, the effects of isopeptides on DDT-induced decoupling in human osteoclast cells can be determined. Thus in one aspect, the isopeptides according to the invention are used to inhibit or prevent decreases induced by the GJIC tumor promoter (KK Hong, et al., (1997) Science., 278-1073-1077). In an exemplary assay, human osteoblast cells are isolated from human bone marrow obtained by puncturing the posterior iliac spine of healthy volunteers (ages 20-36). Approximately 10-15 ml of bone marrow material was collected in 15 ml of PBS + Ca, Mg (Life Technologies, Cat. No. 14040) with 100 U / ml Heparin (Sigma, Cat. No. H-3149). The mononuclear fraction of the marrow is isolated in a Lymphoprep gradient (Nycomed Pharma, Cat. No. 1001967), by centrifugation at 2200 rpm for 30 minutes. After harvesting, the mononuclear fraction was washed once with culture medium and centrifuged at 1800 rpm for 10 minutes. The cells were then counted and plated in culture medium at 8xl08 cells / 100 mm per dish. The medium was changed the next day and the cells were cultured at 37 ° C in 5% C02 with medium changes every 7 days. After 3-4 weeks of culture, the cells typically reach 70% confluence. The medium was then supplemented with 100 nM dexamethasone (Sigma, Cat. No. D-4902) for 7 days. The cells were then plated for video imaging experiments. Generally, cells are plated at 2.5xl05 cells / slide cover and cultured for 2-3 days before imaging.

After culturing the cells are fixed in a PDMI-2 culture chamber (Medical Systems Corp.), maintained at 37 ° C with superfused C0, in a Zeiss Axiovert microscope. Microinjections are performed using a micropipette that is loaded with a 10 mM Lucifer yellow solution (Sigma, Cat. No. L-0259). A cell is injected carefully into the monolayer with LY for 30 seconds; The micropipette is removed from the cell and after 30 seconds the number of cells showing dye transfer is counted. For a subset of cell cultures, DDT is added to the medium in a final concentration of 13μM, and left for 60 minutes. The images of the cells are acquired with an intensified CCD camera (Dage MTI) and digitized with a Matrox MVP image processor board, using the MetaMorph imaging software (Universal Imaging). Under control conditions (without treatment with DDT), the dye is generally spread to a median of 14.5 cells (n = 12). Cells exposed to DDT typically exhibit decreased cell coupling with a median of 7 (n = 13). Isopeptides are added to the bath solution in a final concentration of 10"3 mol / 1 and after 10 minutes, another microinjection is carried out Preferably, the agonist isopeptides according to the invention show an increase in the dye transfer from cell to cell.More preferably, this increase is significantly different from the control samples (without peptides) as determined by using routine statistical tests, such as the non-parametric statistical test of ilcoxon (with p <; 0.05). preferably, the isopeptides show decreases in GJIC inhibition which are at least about 50%, preferably about 70% and more preferably, about 100% or greater. That the decreases observed for AAP. This assay can be used to identify candidate isopeptides with the greatest therapeutic efficacy in reversing decreased intercellular coupling related to tumor promotion and in one aspect, such isopeptides are administered to individuals at risk of developing or having cancer. An isopeptide or in combination with other isopeptides and / or in combination therapy with other anticancer agents can be used. Still other assays can be carried out to identify isopeptides that produce substantially the same physiological responses as the AAR antiarrhythmic peptides; AAP10, HP, and their functional analogues (for example, to identify agonists) or which inhibit or suppress these physiological responses (for example, to identify antagonists). Suitable assays include, but are not limited to: assays to measure the formation of cAMP in cells (e.g., CHO cells); cAMP efficacy assays (e.g., to measure the inhibition of forskolin-stimulated cAMP formation of APP-like compound in CHO cells); return of phosphoinositol in cardiomyocytes (Meier et al.) (E. Meier, et al (1997) Drug Development Research, 40. 1-16); and responses to the suppression of glucose and oxygen. A number of different standard tests are detailed above. PCT / US 02/05773 are described in additional tests, presented on February 22, 2002, all of which are incorporated herein by reference. These assays are only exemplary and other suitable assays that can be developed and standardized are encompassed within the scope of the invention.

Pharmaceutical Compositions The invention also relates to a pharmaceutical composition comprising one or more of any of the above described isopeptides in combination with a pharmaceutically acceptable carrier and / or diluent.

Formulation / carrier For therapeutic use, the chosen isopeptide of the invention is formulated with a carrier that is pharmaceutically acceptable and is suitable for delivering isopeptide via the chosen administration route. For the purpose of the present invention, peripheral parenteral routes include routes of intravenous, intramuscular, subcutaneous and intraperitoneal administration. Certain compounds used in the present invention may also be related for administration by the oral, rectal, nasal, or lower respiratory routes. These are the so-called non-parenteral routes. The present pharmaceutical composition comprises an isopeptide of the invention, or a salt thereof and a pharmaceutically acceptable carrier. Suitable pharmaceutically acceptable carriers are those that are conventionally used with peptide-based drugs, such as diluents, excipients and the like. Pharmaceutically acceptable carriers for therapeutic use are well known in the pharmaceutical arts and are described, for example, in Remington's Pharmaceutical Sciences, Mack Publishing Co. (A. R. Gennaro, 1985). For example, a sterile saline solution and a saline solution buffered with phosphate at a slightly acidic or physiological pH can be used. The buffering agents of the pH can be histidine or sodium acetate. Preservatives, stabilizers, colorants and even flavoring agents can be supplied in the pharmaceutical composition. For example, sodium benzoate phenol, sorbic acids and esters of p-hydroxybenzoic acid can be added as preservatives. In addition, antioxidants and suspending agents may be used for example, SDS, ascorbic acid, methionine, carboxy methyl cellulose, EDTA, polyethylene glycol, and Troeen. The pharmaceutical compositions of the present invention can be formulated and used as tablets, capsules or elixirs for oral administration, suppositories for rectal administration; sterile solutions or suspensions for injectable administration and the like. The dosage and method of administration can be designed to achieve optimal efficacy but will depend on factors such as diet weight, concurrent medication and other factors, which will be recognized by those skilled in the medical arts. The pharmaceutical carrier or diluent used can be a conventional solid or liquid carrier. Examples of the solid carriers are lactose, terra alba, sucrose, cyclodextrin, talc, gelatin, agar, pectin, acacia, magnesium stearate, stearic acid or lower alkyl cellulose ethers. Examples of the liquid carriers are syrup, peanut oil, olive oil, phospholipids, fatty acids, fatty acid amines, polyoxyethylene and water. Similarly, the carrier or diluent can include any sustained release material known in the art, such as glyceryl monostearate or glyceryl distearate, alone or mixed with a wax. Parenteral Administration When administering parenterally, such as subcutaneously on a daily basis, injectable pharmaceutical compositions can be prepared in conventional forms either as aqueous solutions or freeze-dried suspensions, solid forms suitable for reconstitution immediately before or liquid suspension prior to the invention. , or as emulsions. Suitable excipients are, for example, water, saline, dextrose, mannitol, lactose, lecithin, albumin, sodium glutamate and cysteine hydrochloride. In addition, if desired, the injectable pharmaceutical compositions may contain minor amounts of non-toxic auxiliary substances such as wetting agents or pH buffering agents. Absorption enhancing preparations (e.g., liposomes) can be used. In one embodiment of the invention, the compounds are formulated for infusion administration, for example, when they are used as liquid nutritional supplements for individuals in a total parenteral nutrition therapy (e.g., neonates), or by injection, for example. , subcutaneously, intraperitoneally or intravenously and thus are used as aqueous solutions in sterile, pyrogen-free form and are optionally buffered to a physiologically tolerable pH, a slightly acidic or physiological pH. The formulation for intramuscular administration can be based on solutions or suspensions in plant oil, for example, canola oil, corn oil or soybean oil. These oil-based formulations can be stabilized by antioxidants, for example, BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene). Thus, the current isopeptide compounds can be administered in a vehicle such as distilled water or phosphate buffered saline, 5% dextrose solutions or oils. The solubility of the current isopeptides can be enhanced if desired by incorporating a solubility enhancer such as detergents and emulsifiers. The carrier or aqueous carrier may be supplemented for use as an injectable with an amount of gelatin that serves to deposit the isopeptide at or near the injection site, for its slow release to the desired site of action. Alternative gelling agents, such as hyaluronic acid may also be useful as depositing agents. The isopeptides of the invention can also be formulated as a slow release implant device for prolonged and sustained administration of the isopeptides. Such sustained release formulations may be in the form of a patch positioned externally in the body. Examples of the sustained release formulations include biocompatible polymer compounds, such as poly (lactic acid), poly (lactic-co-glycolic acid), methylcellulose, hyaluronic acid, collagen, liposomes and the like. Sustained release formulations are of particular interest when it is desirable to provide a high local concentration of an isopeptide of the invention. The isopeptide can be used in the form of a sterile filled vial or vial containing an intestinotropic amount of the peptide, either in unit dose or in multidose amounts. The vial or vial can contain the isopeptide and the desired carrier, as a ready-for-administration formulation. Alternatively, the vial or vial may contain the isopeptide in a form, such as a lyophilized form suitable for reconstitution in a suitable carrier such as sterile water or phosphate buffered saline.

Non-parenteral administration As an alternative for injectable formulations, the isopeptide can be formulated for administration by another route. Oral dosage forms such as tablets, capsules and the like can be formulated in accordance with standard pharmaceutical practice. It will be appreciated that the current preferred amounts of active compounds used in a given therapy will vary according to for example, the specific compound to be used, the particular formulated composition, the mode of administration and the characteristics of the subject, e.g., the species, sex, weight, general health and age of the subject. The optimal administration rates for a given administration protocol can be easily determined by those skilled in the art by using conventional dose determination tests performed with respect to the above guidelines. Suitable dose ranges can include from about 1 mg / kg to about 100 mg / kg of body weight per day.

Methods of treatment In one aspect, the invention provides a method of administration to an individual who has or is at risk of developing, conditions associated with weakened GJIC, a therapeutically effective amount of any of the above-described isopeptides. Individuals that can be treated using the isopeptides according to the invention include, but are not limited to animals, preferably mammals, eg, rodents (including mice, rats, hamsters and lagomorphs, such as rabbits), dogs, pigs, goats (usually any domestic animal) and primates. In a preferred aspect, an individual is a human being. Examples of conditions that can be treated include but are limited to cardiovascular disease, airway epithelial inflammation, alveolar tissue disorders, bladder incontinence, hearing due to cochlear diseases, endothelial lesions, diabetic retinopathy and neuropathy diabetic, ischemia of the central nervous system and the spine, dental tissue disorder including periodontal disease, kidney diseases, failure of bone marrow transplantation, wounds, erectile dysfunction, urinary bladder incontinence, neuropathic pain, subchronic and chronic inflammation, cancer and bone marrow failure and stem cell transplantation, conditions that result during the transplantation of cells and tissues or during medical procedures such as surgery, as well as conditions caused by an excess of reactive oxygen species and / or free radicals and / or nitric oxide. In a preferred aspect, the invention provides a pharmacologically active antiarrhythmic isopeptide and the use thereof, for the treatment of arrhythmia and thrombotic complications that result during cardiovascular disorders such as acute ischemic heart disease (eg angina pectoris stable, angina pectoris unstable) , acute myocardial infarction), congestive heart failure (for example systolic, diastolic, high production, low production, heart failure of the right or left side), congenital heart disease, cor pulmonale, cardiomyopathy, myocarditis, hypertensive heart disease during revascularization coronary and similar. In specific embodiments, an antiarrhythmic isopeptide according to the present invention is used to treat and / or prevent bradyarrhythmias (e.g. due to disease in the sinus nodes, AV nodes, His bundle, right or left bundle branch) and tachyarrhythmias associated with reentry (eg, aerial premature complexes, AV junction complexes, ventricular premature complexes, atrial fibrillation, atrial flutter, paroximal supraventicular tachycardia, nasal sinus node reentrant tachycardia, AV nodal reentrant tachycardia, and ventricular tachycardia do not sustained) either alone or in combination with other antiarrhythmic compounds such as class I agents (for example lidocaine), class II agents (for example metoprolol or propanolol), class III agents (for example amiodarone or sotalol) or class IV agents (for example verapemil). Additionally or alternatively, the isopeptides according to the invention are used to treat one or more of a reentrant arrhythmia, ventricular reentry (e.g. such as elevations during acute myocardial infarction, chronic myocardial infarction, stable pectoris angina and pectoris angina). unstable); infectious or autonomic cardiomyopathy; atrial fibrillation; alternate repolarization, monomorphic ventricular tachycardia; alternans of T waves, bradyarrhythmias and generally reduced contractile thrombosis of cardiac tissue and the like.

Osteoporosis In a further aspect, the isopeptides according to the invention are used to prevent and / or treat osteoporosis or other pathologies that affect bone formation, growth or maintenance. Isopeptides that can normalize attenuated GJIC between human osteoblasts during hypoxia are particularly suitable for the treatment of bone diseases with weakened bone formation in relation to bone resorption. Optimal isopeptides for use in such methods can be selected in assays for increased activity of alkaline phosphatase (ALP) in osteoblasts, which provides a method for monitoring cell viability and growth as a consequence of the proper maintenance of GJIC. In one aspect, human osteoblasts are stimulated with different concentrations of isopeptides from 1 x 10"13 to 1 x 10 ~ 6 mol / l, and compared with untreated controls. Under normal culture conditions, isopeptides preferably increase the ALP activity Even more preferably, the isopeptides stimulate the activity of ALP during the hypoxic conditions at concentrations in the range of 10-11 to 10-6 mol / 1. The assay can thus be used to optimize compositions of isopeptides for the treatment and / or prevention of bone diseases associated with poor vascularity, hypoxia, and ischemia in bone tissue.

Joint diseases In another aspect, the isopeptides according to the invention are used for the prevention and / or treatment of joint diseases involving weakened cell-to-cell coupling. For example, isopeptides can be used for the prevention and / or treatment of joint diseases involving metabolic stress. These would include any form of arthritis associated with decreased vascularization or tissue healing of fractured cartilage.

Cancer In still another aspect, the isopeptides according to the invention are used to treat cancer. carcinogenesis is characterized by the progressive weakening of the growth control mechanisms in which growth factors, oncogenes and tumor suppressor genes are involved. A general theme in carcinogenesis and tumorigenesis is the down regulation of GJIC. The permeability of space junctions in tumor cells when using a dye transfer assay is typically inferior to GJIC in the surrounding tissue. In addition, the opening of space junctions is known to be effected by tumor promoters which decreases GJIC. Therefore in one aspect, the isopeptides according to the invention are used as drugs for the treatment of cancer alone or in conjunction with traditional anti-cancer therapies.

Wound healing In a further aspect, the isopeptides according to the invention are used to treat wounds and in particular to accelerate wound healing. Wound healing involves the interactions of many cell types, and intercellular communication mediated by space junctions is considered to play an important role in the coordination of cell metabolism during the growth and development of cells involved in tissue repair and regeneration ( KM Abdullah, et al., (1999) Endocrine, 10 35-41; M. Saitoh, et al. (1997) Carcinogenesis, 18: 1319-1328; J. A. Goliger, et al. (1995) Mol. Biol .. Cell, 6 1491-1501). Isopeptides can be administered to the site of a wound by topical administration using carriers well known in the art (eg ointments, creams, etc.) or can be administered systemically for example to treat wounds of internal tissues such as in the treatment of injuries for chronic gastric ulcers.

Ischemia Additional functions in which the intercellular junctional communication of endothelial spaces has been implicated is the migratory behavior of endothelial cells after injury, angiogenesis, endothelial growth and senescence and the coordination of vasomotor responses (GJ Christ, et al., (2000) Braz J Med Biol. Res., 33: 423-429). Therefore in one aspect, an isopeptide according to the invention is used to enhance vascular responses and to improve blood supply during conditions with increased metabolic demand (eg, physical exercise, tachycardia) and during ischemia. Space junctions are also believed to provide a molecular bond for long-term coordinated signaling between individual members of glial behavior. Similarly, astrosites are ideally suited for the metabolic support of neurons since they are functionally polarized with one extremity touching the vascular event and the other pole approaches the neuronal parenchyma (R. Dermietzel (1998) Brain Res. Brain Res. Rev. ., 26: 176-183). Therefore in a preferred embodiment, the isopeptides according to the invention are administered to an individual who needs to avoid ischemic damage in the brain by increasing the metabolic support between glia cells and neurons. Such individuals may include individuals with organic psychosis, which may be present with signs such as depression, anxiety, memory and learning deficits, phobias and hallucinations or individuals who have suffered a traumatic brain injury. Preferably, such isopeptides are selected or formulated so as to be available to the central nervous system (ie, supplied with or conjugated with carriers which facilitate transport through the brain and blood barrier). Isopeptides according to the invention can also be used to accelerate repair after nerve damage or during immature cell grafting (progenitor cells) in brain tissue for example such as in individuals with neurotrauma, brain ischemia and chronic neurodegenerative diseases such as Parkinson's disease or Huntington's disease (H. Aldskogius, et al., (1998) Prog. Neurobiol, 55 : 1-26). In specific embodiments, an isopeptide according to the present invention can be used, due to the effect on the intercellular spaces junction channels, to treat and / or prevent cataracts (D. Mackay, et al., (1999) Am J Hum Genet , 64 1357-1364), treat and / or prevent corneal vascularization in disease states with poor nutrition of the cornea, and increase the healing of corneal lesions (SG Spanakis, et al., (1998) Invest Ophtalmol Vis Sci., 39: 1320-1328) and / or avoid hypertension. It will be obvious to those skilled in the art, that the isopeptides and the pharmaceutical compositions according to the invention, can be used to treat any condition or pathology associated with weakened space junction communication (abnormal decreases or increases). Preferably, one or more of the isopeptides or pharmaceutical compositions comprising the one or more isopeptides, are administered to an individual in need thereof in a therapeutically effective amount. As used herein, a "therapeutically effective amount" is one which reduces the symptoms of a given condition or pathology, and which preferably normalizes the physiological responses in an individual with the condition or pathology. The reduction of symptoms or normalization of physiological responses can be determined by using routine methods in the art and can vary with a given condition or pathology. In one aspect, a therapeutically effective amount of one or more isopeptides or pharmaceutical composition comprising the one or more isopeptides is an amount that reestablishes a physiological parameter measurable to substantially the same value (preferably up to within + 30%, more preferably up to of + 20%, and still more preferably up to 10% of the value) of the parameter in an individual without the condition or pathology.

Experiments The invention will now be further illustrated with reference to the following examples. It will be appreciated that the following is by way of example only and that modifications to detail may be made while still falling within the scope of the invention.

Example 1. Synthesis of Isopeptides A preferred general procedure is described below. However, more detailed descriptions of solid phase isopeptides are found in 098/11125 incorporated herein in their entirety. to. General Isopeptide Synthesis Apparatus and Synthetic Strategy The isopeptides were batch synthesized in a polyethylene vessel equipped with a polypropylene filter for filtration using 9-fluorenylmethyloxycarbonyl (Fmoc) as a protective Na-amino group and common protective groups suitable for the functionalities of the side chain.

Solvents The solvent DMF (N, N-dimethylformamide, Riedel de-H in, Germany) was purified by passing through a column packed with a strong cation exchange resin (Lewatit S 100 MB / H strong acid, Bayer AG Leverkusen, Germany) and analyzed by free amines prior to use by the addition of 3, 4-dihydro-3-hydroxy-4-oxo-l, 2,3-benzotriazino (Dhbt-OH) giving rise to a yellow color) if free amines are present. The solvent DCM (dichloromethane, analytical grade, Riedel Háen, Germany) was used directly without purification. Acetonitrile (CLAR grade, Lab-Sean, Dublin Ireland) was used directly without purification.

Amino Acids The Fmoc and Boc protected amino acids were purchased from Advanced ChemTech (ACT), Bachem, NovaBiochem and Neosystem.

Derivatives of Benzoic Acid and Benzylamine The benzoic acid and benzylamine derivatives were purchased from Aldrich and used without further purification.

Coupling Reagents The diisopropylcarbodiimide coupling reagent was purchased from (Riedel de-Háen, Germany), PyBop from Advanced ChemTech.

Linkers (4-hydroxymethylphenoxy) acetic acid (HMPA) was purchased from Novabiochem, Switzerland; and coupled to the resin as a preformed 1-hydroxybenzotriazole ester (HOBt) generated by means of DIC.

Solid supports The isopeptides were synthesized according to the Fmoc strategy in TentaGel S 0.22-0.31 resins (TentaGel-S-NH2, TentaGel S-Ram, Rapp polymer, Germany).

Catalysts and other reagents Diisopropylethylamine was purchased from Aldrich, Germany, and the fluke ethylenediamine, piperidine and pyridine from Riedel-de H, Frankfurt, Germany. 4- (N, N-dimethylamino) pyridine (DMAP) was purchased from Fluka, Switzerland and used as a catalyst in coupling reactions involving symmetric anhydrides. Tanditiol was purchased from Riedel-de Háen, Frankfurt, Germany. 3, 4-Dihydro-3-hydroxy-4-oxo-l, 2,3-benzotriazino (Dhbt-OH), 1-hydroxybenzotriazole (HOBt) (HOAt) is obtained from Fluka, Switzerland.

Coupling Procedures The first amino acid was coupled as an asymmetric anhydride in dmf generated from the appropriate n-a-protected amino acid and dic. The following amino acids were coupled as the hobt or hoat esters generated in situ made of appropriate n-a-protected amino acids and hobt or hoat by means of dic in dmf. The acylations were verified by the ninhydrin test carried out at 80 ° C in order to prevent Fmoc deprotection during the test (B. D. Larsen, A. Holm, Int.J.P.Protein Res., 1994, 43 1-9).

Deprotection of the N-amino protecting group (Fmoc) Deprotection of the Fmoc group was performed by treatment with 20% piperidine in DMF (1x5 and 1x10 min.), Followed by washing with DMF (5 x 15 ml, 5 min. each) until the yellow color could be detected after the addition of Dhbt-OH to the drained DMF.

Deprotection of Alil / Aloc A solution of 3 eq. Pd (PPh3) 4 dissolved in 15-20 ml of CHC13, NMM (37: 2: 1) was added to the peptide resin. The treatment was continued for three hours at room temperature accompanied by bubbling a stream of N through the mixture.

Coupling of HOBt-esters 3 eq. of amino acid N-a-amino protected in DMF together with 3 eq. HOBt and 3 eq. DIC and then added to the resin.

Preformed symmetric anhydride. 6 eq. of amino acid N-a-amino protected in DCM and cooled to 0 ° C. The DIC (3 eq.) Was added and the reaction was continued for 10 min. The solvent was removed in vacuo and the remainder dissolved in DMF. The solution was immediately added to the resin followed by 0.1 eq. of DMAP.

Cleavage of Isopeptide from Resin with Acid Isopeptides were split from the resins by treatment with 95% trifluoroacetic acid (TFA, Riedel-de Háen, Frankfurt, Germany) -water v / vo with 95% TFA and 5% ethanedithiol v / at room temperature for 2 h. The filtered resins were washed with 95% TFA-water and the filtrates and washes were evaporated under reduced pressure. The residue was washed with ether and dried by freezing from acetic acid-water. The crude freeze-dried product was analyzed by high-performance liquid chromatography (HPLC) and identified by electro-ionization ionization mass spectroscopy (ESEM).

Batch synthesis of the isopeptide in TentaGel resin (PEG-PS) The TentaGel resin (1 g, 0.22-0.31 mmol / g) was placed in a polyethylene container equipped with a polypropylene filter for filtration. The resin expanded in DMF (15 ml), and treated with 20% piperidine in DMF to ensure the presence of non-protonated amino group in the resin. The resin was drained and washed with DMF until the yellow color could not be detected after the addition of Dhbt-OH to the drained DMF. The HMPA (3 eq.) Was coupled as a preformed HOBt-ester as described above and the coupling was continued for 24 h. The resin was drained and washed with DMF (5x5 ml, 5 min, each) and the acylation was verified by the ninhydrin test. The first amino acid was coupled as a preformed symmetric anhydride as described above. The following amino acids in accordance with the sequence were coupled as the preformed Fmoc-protected esters (3 eq.) As described above. The couplings were continued for 2 h, unless otherwise specified. The resin was drained and washed with DMF (5 x 15 ml, 5 min each) in order to remove excess reagent. All the acylations were verified by the ninhydrin test carried out at 80 ° C. After completing the synthesis, the isopeptide resin was washed with DMF (3x15 ml, 5 min each), DCM (3x15 ml, 1 min each) and finally diethyl ether (3x15 ml, 1 min each) and dried in vacuo.

Preparative HPLC conditions Preparative chromatography was carried out using a VISION workstation (PerSeptive Biosystem) equipped with an AFC2000 automatic fraction autosampler / collector. VISION-3 software was used to control and acquire data. For preparative HPLC, different columns were used such as Kromasil (EKA Chemicals) KR100-10-C-8, 100A, C-8, 10 um; CER 2230, 250 x 50, 8 mm or one VYDAC 218 TP101550, 300Á, C-18, 10-15 um, 250 x 50 mm. The buffer solution system includes: A: 0.1% TFA in MQV; B: 0.085% TFA, 10% MQV, 90% MeCN. Flow ratio 35-40 ml / min. The preferred column temperature was 25 ° C. UV detection was carried out at 215 nm and 280 nm. Suitable gradients were used for individual isopeptides.

Analytical CLAR conditions The gradient CLAR analysis was completed using a HP 1100 Hewlett Packard HPLC system consisting of an HP 1100 quaternary pump, an HP 1100 autosampler, an HP 1100 column thermostat, and an HP 1100 multiple wavelength detector. Hewlett Packard Chemstation for LC software (rev A. 06.01) was used for instrument control and data acquisition. For analytical HPLC, different columns were used such as VYDAC 238TP5415, C-18, 5um, 300Á, or a Jupiter, Phenomenex 00F-4053-E0; 5 um C-18, 300Á 150 x 4.6 mm and others. The buffer solution system includes: A: 0.1% TFA in MQV; B: 0, 085% TFA, 10% MQV, 90% MeCN. The flow ratios were 1 ml / min. The preferred column temperature was 40 ° C. UV detection: carried out at 215 nm. As above, suitable gradients were used for the individual isopeptides.

Mass spectroscopy Isopeptides were dissolved in super gradient methanol (Labscan, Dublin, Ireland), Milli-Q water (Millipore, Bedford, MA) and formic acid (Merck, Damstadt, Germany) (50: 50: 0.1 v / v / v) to give concentrations between 1 and 10 μg / ml. The isopeptide solutions (20 μl) were analyzed in positive polarity mode by ESI-TOF-MS using a LCT mass spectrometer (Micromass, Manchester, UK) accuracy of +/- 0.1 m / z. Exemplary synthesis schemes are shown in Figures IA and IB. b. Synthesis of individual isopeptides Synthesis of H-Gly-iso-Lys (4-nor trobenzoyl) -OH (Compound 1) In this, and all subsequent syntheses described herein, dry TentaGel-S-NH2 (0.23 mmol / g , 1 g) was placed in a polyethylene vessel equipped with a polypropylene filter for filtration and treated as described under "synthesis of biosynthetic isopeptide in TentaGel resin". The lysine was coupled as Fmoc-Lys (Aloe) -Oh and Glycine as the Boc derivative. The Aloe protective group was removed as described above. The lysine was coupled to the solid support as the symmetric anhydride followed by deprotection of the Aloe group. The glycine was then coupled to the e-amino group of lysine. The Fmoc group is then removed and subsequently the 4-nitrobenzoic acid is coupled as a HOBt ester generated in situ by means of DIC in THF. All couplings were continued for at least 2 hours. the acylations were checked by the ninhydrin test carried out at 80 ° C as previously described. After completing the synthesis, the isopeptide resin was washed with DMF (3x 15 ml, min each), DCM (3x 15 ml, 1 min each), diethyl ether (3x 15 ml, 1 min each) ) and dried in vacuo. The isopeptide was then cleaved from the resin as described above and dried by freezing. This procedure was followed by all the isopeptides exemplified further below. After purification using preparative HPLC as described above, 40 mg of the isopeptide product were collected with a purity greater than 99%. The identity of the isopeptide was confirmed by ER-MS (found MH + 352.07, calculated MH + 352.24).

Synthesis of H-Gly-iso-Lys (4-methoxybenzoyl) -OH (Compound 4) The lysine was coupled as Fmoc-Lys (Aloe) -OH and Glycine as the Boc derivative. The Aloe protective group was removed as described above. The lysine was coupled to the solid support as the symmetric anhydride followed by the deprotection of the Aloe group. The glycine was then coupled to the e-amino group of Lysine. The Fmoc group was then removed and the 4-methoxybenzoic acid was subsequently coupled as a HOBt ester generated in situ by means of DIC in DMF. After purification using preparative HPLC as described above, 25 mg of the isopeptide product was collected with a purity greater than 98%. The identity of the isopeptide was confirmed by ER-MS (found MH + 337.16, calculated MH + 337.27).

Synthesis of H-Gly -i so -D-Lys (4-methoxybenzoyl) -OH (Compound 18) Lysine was coupled as Fmoc-D-Lys (Aloe) -OH and Glycine as the Boc derivative. The Aloe protective group was removed as described above. The lysine was coupled to the solid support as the symmetric anhydride followed by deprotection of the Aloe group. The glycine was then coupled to the e-amino group of Lysine. The Fmoc group was then removed and the 4-methoxybenzoic acid was subsequently coupled as a HOBt ester generated in situ by means of DIC in DMF. After purification using preparative HPLC as described above, 35 mg of the isopeptide product was collected in a purity greater than 99%. The identity of the isopeptide was confirmed by ER-MS (found MH + 337.13, calculated MH + 337.21).

Synthesis of H-Gly-iso-D-Lys (4-nor trobenzoyl) -OH (Compound 19) Lysine was coupled as Fmoc-D-Lys (Aloe) -OH and Glycine as the Boc derivative. The protecting group was removed as described above. The lysine was coupled to the solid support as the symmetric anhydride followed by deprotection of the Aloe group. The glycine was then coupled to the e-amino group of lysine. The Fmoc group was then removed and the 4-nitrobenzoic acid was subsequently coupled as a HOBt ester generated in situ by means of DIC in THF. After purification using preparative HPLC as described above, 31 mg of the isopeptide product was collected with a purity greater than 99%. The identity of the isopeptide was confirmed by ER-MS (found MH + 352.07, calculated MH + 352. 24).

Synthesis of H-iso-Asn (NH ((4-methoxybenzyl)) -Ala-OH (Compound 57) Alanine was coupled as Fmoc-Ala-OH and asparagine as the derivative The Fmoc protecting group was removed as described The alanine was coupled to the solid support as the symmetrical anhydride followed by deprotection of the Fmoc group, the aspartic acid was then coupled via the carboxylic acid side chain to the a-amino group of the alanine, the Fmoc group was then removed. and the 4-methoxybenzylamine was subsequently coupled to the asparagine-derived carboxylic acid derived by DIC and HOBt in DMF After purification using preparative HPLC as described above, 20 mg of the isopeptide product was collected in a purity greater than 98% Identity of the isopeptide was confirmed by ER-MS (found MH + 323.16, calculated MH + 323.25).

Synthesis of H-iso-Asn (NH ((4-nitrobenzyl)) -AlaOH (Compound 58) Alanine was coupled as Fmoc-Ala-OH and asparagine as the Boc-Asp-OFm derivative. The Fmoc protecting group was removed as described above. The alanine was coupled to the solid support as the symmetric anhydride followed by deprotection of the Fmoc group. The aspartic acid was then coupled via the carboxylic acid side chain to the α-amino group of alanine. The Fmoc group was then removed and the 4-nitrobenzylamine was subsequently coupled to the α-carboxylic acid of the asparagine derived by means of DIC and HOBt in DMF. After purification using preparative HPLC as described above, 56 mg of the isopeptide product was collected in a purity greater than 98%. The identity of the isopeptide was confirmed by ER-MS (found MH + 338.12, calculated MH + 338.22).

Synthesis of H-iso-Asn (NH ((4-methoxybenzyl) -D-Ala-OH (Compound 72) The alanine was coupled as Fmoc-D-Ala-OH and asparagine as the Boc-Asp-OFm derivative. Fmoc protecting group was removed as described above.Alanine was coupled to the solid support as the symmetric anhydride followed by deprotection of the Fmoc group.Aspartic acid was then coupled via a carboxylic acid side chain to the a-amino group of the The Fmoc group was then removed and the 4-methoxybenzylamine was subsequently coupled to the asparagine-derived carboxylic acid by means of DIC and HOBt in DMF After purification using preparative HPLC as described above, 16 mg of the product of isopeptide was collected with a purity greater than 99% The identity of the isopeptide was confirmed by ER-MS (found MH + 323.16, calculated MH + 323.24).

Synthesis of H-iso-Asn (NH ((4-n-trobenzyl)) -D-Ala-OH (Compound 73) Alanine was coupled as Fmoc-D-Ala-OH and asparagine as the Boc-Asp-OFm derivative The Fmoc protecting group was removed as described above.Alanine was coupled to the solid support as the symmetrical anhydride followed by deprotection of the Fmoc group.Aspartic acid was then coupled via a carboxylic acid side chain to the a-amino group of the Alanine The Fmoc group was then removed and the 4-nitrobenzylamine was subsequently coupled to the carboxylic acid of the asparagine derivative by means of DIC and HOBt in DMF After purification using preparative HPLC as described above, 31 mg of the product of isopeptide was collected with a purity greater than 99% The identity of the isopeptide was confirmed by ER-MS (found MH + 338.12, calculated MH + 338.22).

Synthesis of H-iso-Gln (NH ((4-methoxybenzyl)) -Ala-OH (Compound 101) The alanine was coupled as Fmoc-Ala-OH and Glutamine as the Boc-Glu-OFm derivative.The protective group Fmoc The alanine was coupled to the solid support as the symmetrical anhydride followed by deprotection of the Fmoc group.The glutamic acid was then coupled via a carboxylic acid side chain to the a-amino group of the alanine. Fmoc group was then removed and the 4-methoxybenzylamine was subsequently coupled to the a-carboxylic acid of the Glutamine derivative by means of DIC and HOBt in DMF.After purification using preparative HPLC as described above, 27 mg of the isopeptide product it was collected with a purity greater than 99% The identity of the isopeptide was confirmed by ER-MS (found MH + 337.13, calculated MH + 337.25).

Synthesis of H-iso-Gln (NH ((4-ni trobenzyl)) -Ala-OH (Compound 102) Alanine was coupled as Fmoc-Ala-OH and Glutamine as the Boc-Glu-OFm derivative. Fmoc protector was removed as described above.Alanine was coupled to the solid support as the symmetrical anhydride followed by deprotection of the Fmoc group.The glutamic acid was then coupled via a carboxylic acid side chain to the a-amino group of alanine The Fmoc group was then removed and 4-nitrobenzylamine was subsequently coupled to the glutamine a-carboxylic acid derivative by means of DIC and HOBt in THF After purification using preparative HPLC as described above, 22 mg of the product of Isopeptide was collected with a purity greater than 98% The identity of the isopeptide was confirmed by ER-MS (found MH + 352.15, calculated MH + 352.2).

Synthesis of H-iso-Gln (NH ((4-methylbenzyl)) -Ala-OH (Compound 107) The alanine was coupled as Fmoc-Ala-OH and Glutamine as the derivative The Fmoc protecting group was removed as described The alanine was coupled to the solid support as the symmetrical anhydride followed by deprotection of the Fmoc group.The glutamic acid was then coupled via a carboxylic acid side chain to the a-amino group of alanine.The Fmoc group was then removed and the 4-methylbenzylamine was subsequently coupled to the glutamine α-carboxylic acid derivative by means of DIC and HOBt in DMF.After purification using preparative HPLC as described above, the isopeptide product was collected and the identity of the isopeptide was confirmed by ER-MS.

Synthesis of H-iso-Gln (NH ((4-methoxybenzyl)) -D-Ala-OH (Compound 116) The alanine was coupled as Fmoc-D-Ala-OH and glutamine as the Boc-Glu-OFm derivative. The Fmoc protecting group was removed as described above. The alanine was coupled to the solid support as the symmetric anhydride followed by deprotection of the Fmoc group. The glutamic acid was then coupled via a carboxylic acid side chain to the a-amino group of Alanine. The Fmoc group was then removed and the 4-methoxybenzylamine was subsequently coupled to the a-carboxylic acid of the glutamine derivative by means of DIC and HOBt in DMF. After purification using preparative HPLC as described above, 11 mg of the isopeptide product was collected in a purity greater than 98%. The identity of the isopeptide was confirmed by ER-MS (found MH + 337.22, calculated MH + 337.28).

Synthesis of H-iso-Gln (NH ((4-nitrobenzyl)) -D-Ala-OH (Compound 117) The alanine was coupled as Fmoc-D-Ala-OH and glutamine as the Boc-Glu-OFm derivative. The Fmoc protecting group was removed as described above.Alanine was coupled to the solid support as the symmetrical anhydride followed by deprotection of the Fmoc group.The glutamic acid was then coupled via a carboxylic acid side chain to the a-amino group of The Fmoc group was then removed and the 4-nitrobenzylamine was subsequently coupled to the glutamine a-carboxylic acid derivative by means of DIC and HOBt in DMF.After purification using preparative HPLC as described above, 24 mg of the Isopeptide product was collected with a purity greater than 96% Identity of the isopeptide was confirmed by ER-MS (found MH + 352.12, calculated MH + 352.22).

Example 2. Effect of Isopeptides in Calcium-Induced Arrhythmias The anti-arrhythmic effect of isopeptides was tested in a model of calcium-induced arrhythmias according to the model of Lynch et J. Pharmacol. (1981), 3: 49-60. Male NMRI mice (25-30 grams, Bomholdtgaard, Ll. Skendsved, Denmark) were anesthetized with an anesthetic combination of neurolept (Hynorm® (fentanyl citrate 0.315 mg / ml and fuanisone 10 mg / ml) and midazolam at 5 mg / ml The commercial solutions Hynorm® and midazolam were diluted 1: 1 in distilled water and one part of Hynorm® was mixed with a part of diluted midazolam.Anesthesia is induced by sc administration of this solution in a dose of 50-75 ul / 10 grams of mouse. The intravenous cannula is inserted into the vein of the tail. The signal load II ECG is recorded continuously by placing stainless steel ECG electrodes on the right front member and on the left rear leg. The seeded electrode is placed on the right rear leg. The signal is amplified (x 5,000-10,000) and filtered (0.1-150 Hz) by means of a module Hugo Sachs Electronic model 689 ECG. The analog signal is digitized by means of a 12-bit data acquisition board (Data Translation model DT321) and placed on samples at 1000 Hz using the Notocord HEM 3.1 software for Windows NT. After a 10 minute balancing period, the isopeptide test sample was injected into the tail vein at a dose of 1 nmol / kg and three minutes later an intravenous infusion of CaCl2 (30 mg / ml, ~ 100 mg / kg / min, chloride) was started of calcium-2-hydrate, Riedel-de Haen, Germany). Mice previously treated with vehicle (saline buffered in phosphate with 0.1% bovine albumin) are tested every day as a measure for the level of control in the untreated animal. The injection volume was 100 ul in all experiments. The waiting time for the onset of arrhythmias is determined as the time from the start of the CaCl2 infusion to the first conduction block event (defined as an intermittent failure of the SA or AV conduction characterized by the activation of delayed P wave). (SA block) or by a P wave without the concomitant QRS complex (AV block).

RESULTS: The% response of the peptide compounds tested is given in Table 2. The response is estimated according to (tarr (test compound) - tarr (vehicle)) x 100 / tarr (vehicle).

Table 2 Compound Name% response SEM +/- 19 H-Gly-iso-D-Lys (4-33-nitrobenzoyl) -OH H-Gly-iso-D-Lys (4-16-12 methoxybenzoyl) -OH 101H -iso-Gln (NH (4-68-10-methoxybenzyl)) -Ala-OH 116 H-iso-Gln (NH (4-25-16 methoxybenzyl) -D-Ala-OH CONCLUSION The peptides of the invention show an antiarrhythmic effect. Definitions Unless otherwise specified, the following definitions are provided for specific terms, which are used in the following written description. Through the description and claims the three-letter code for natural amino acids are used as well as generally accepted three letter codes for other α-amino acids, such as Sarcosine (Sar). Where the L or D form has not been specified, it can be understood that the amino acid in question can be either the L or D form. "Analogs or functional derivatives or modified forms" of an isopeptide means any chemical entity or compound which has a structural conformation and / or binding properties that are sufficiently similar to the endogenous AAP or a functional analogue thereof (eg, such as AAP10 or HP5) or which binds to a receiver bound by AAP to provide one or more of the beneficial effects of maintaining or normalizing the space binding function (i.e., increasing when the binding communication of space deteriorates or inhibits when the space junction communication is overstimulated or uncontrolled). Preferably, such analogs or derivatives are also capable of binding to the carrier isopeptide hPepTl or a structural analogue thereof. As used throughout the specification and claims, the term "isopeptide" is inclusive of an isopeptide, or a functional analog or derivative of such isopeptide as defined above. The term "functional analogue of an isopeptide" is inclusive in addition to peptidomimetics or peptoids. The term "isopeptide mimetic" refers to compounds of both an isopeptide and a non-isopeptide nature. The objective behind the creation of peptidomimetics is to create scaffolds, which can replace the column of the isopeptide. It is assumed that the secondary amide bonds in isopeptides are responsible for the instability and possibly poor transport properties of isopéptido through cell membranes. The proper placement of amino acid side chains with appropriate trajectories is seen as the key design tactic in peptide mimetics of isopeptide to achieve biological activity. Modifications of the column include reducing amide bonds and alkylated amide bonds and the use of isosteric bonds such as thioamide bonds, CH2-CH2, CH = CH. The term "peptoid" refers to compounds that can be characterized by similar topology between the structural formula of the peptoid and the precursor isopeptide. In this manner, a peptoid can be a compound consisting of isopeptide chains of amino acids that carry side chains or the nitrogen atom column instead of the alpha carbon as in the real isopeptides. The peptidomimetics and peptoids may comprise amino acid units having modified side chains, such as Nal, dab and Dapa, or may comprise amino acids D. The various modifications of peptide mimetic and peptide structure described by El Tayar, N et al., (Amino) Acids (1995) 8: 125-139) are included in the definitions herein. The term "halogen" refers to F, Cl, Br, and O, where F and I are preferred. The term "alkyl" refers to univalent groups derived from alkanes by the removal of a hydrogen atom from any carbon atom: CnH2n +? -. The groups derived by removing the hydrogen atom from a terminal carbon atom of unbranched alkanes form a subclass of normal alkyl (n-alkyl) groups: H [CH2] n-. The RCH2- groups, R2CH- (R is not equal to H), and R3C- (R is not equal to H) are primary, secondary and tertiary alkyl groups respectively. The C (1-22) alkyl refers to any alkyl group having from 1 to 22 carbon atoms and includes C (1-6) alkyl, such as methyl, ethyl, propyl, isopropyl, butyl, pentyl and hexyl and all the possible isomers of it. By the phrase "lower alkyl" is meant a straight or branched alkyl having less than about 6 carbon atoms, preferably methyl, ethyl, propyl or butyl.

The term "alkenyl" refers to a straight or branched cyclic hydrocarbon group that contains one or more carbon-carbon double bonds. The alkenyl C (2-22) refers to any alkenyl group having from 1 to 22 carbon atoms and includes C (2-6) alkenyl, vinyl, allyl, 1-butenyl, etc. The term "aralkyl" refers to aryl C (1-22) alkyl, and the term "aryl" through this specification means phenyl or naphthyl. By the phrase "hydrophobic group" is meant an optionally substituted aromatic carbon ring, preferably a 6 or 12 membered aromatic carbon ring. By the phrase "optionally substituted" means the substitution of the 6 or 12 member aromatic carbon ring with at least one of a lower alkyl, alkoxy, hydroxyl, carboxy, amine, thiol, hydrazide, amide, halide, hydroxyl, ether, amine , nitrile, imine, nitro, sulfur, sulfoxide, sulfone, thiol, aldehyde, keto, carboxy, ester, an amide group; including selenium and thio derivatives thereof. Also included in the definition of "optionally substituted" are sulfur, sulfoxide, sulfone, and thiol derivatives with or without a selenium group. In embodiments in which the aromatic carbon ring is substituted, such substitutions will typically be fewer than about 10 substitutions, more preferably about 1 to 5 thereof with about 1 or 2 substitutions being preferred by many applications for the invention. Preferred alkoxy groups include methoxy, ethoxy, and propoxy. Illustrative hydrophobic groups include benzyl, phenyl, and unsubstituted naphthyl. By the phrase "hydrogen bonding group" means a donor or acceptor of a hydrogen bond (non-covalent). In embodiments in which the hydrogen bonding group is a donor, this typically includes at least one electronegative atom linked to a hydrogen atom. Examples of such electronegative atoms include, but are not limited to, nitrogen, oxygen, halide (eg Cl, F, Br, etc.), and sulfur. Exemplary hydrogen bond donors include hydroxyl, amine, thiol, hydrazide and amide. In embodiments in which the first hydrogen bonding group is an acceptor, this preferably includes at least one electronegative atom such as those mentioned above in which the atom includes a pair of unbonded electrons. Such pairs are often referred to as "lone pairs". Examples of preferred hydrogen bond acceptors include, but are not limited to, halide, hydroxyl, ether, amine, nitrile, imine, nitro, aldehyde, keto, carboxy, ester, amide group; and selenium derivatives thereof. Suitable hydrogen sulfide, sulfoxide, sulfone, and thiol hydrogen bond acceptors including selenium derivatives thereof are also screened. The terms "intercell communication modulator", "space junction facilitator", "composite that facilitates space junction communication" and "space junction openers", etc., all refer to a compound that facilitates, or maintains, or normalizes, GJIC, without taking into account the particular mechanism behind this action. More specifically, the term "space junction openers" may refer to a substance which normalizes (ie, increases) the exchange of molecules that are capable of passing through the junctions of space between extracellular and intracellular spaces and / or that can normalize the increased GJIC. The term "agonist" refers to an isopeptide that can interact with a tissue, cell or cell fraction which is the target of an AAP, AAP10, HP5 isopeptide, or functional analogue thereof, to cause substantially the same physiological response in the tissue, cell or cell fractions of AAP, AAP10, HP5 isopeptide, or functional analogue thereof. In one aspect, the physiological response is one or more of: contraction, relaxation, secretion, enzyme activation, etc. Preferably, the isopeptide is linked to the tissue, cells or cell fraction. In one aspect, the isopeptide is bound to a receptor in the tissue, or cells. fraction of cells, which bind to AAP, AAP10, HP5, or a functional analogue thereof. An "anti-arrhythmic peptide agonist" as used herein is an isopeptide, which comprises an antiarrhythmic activity, which is substantially the same, or greater than, the antiarrhythmic activity of an AAP, AAP10, HP5 isopeptide or functional analog of the same. "Greater than" refers to an antiarrhythmic activity, which is observed at lower concentrations of isopeptide or in shorter periods of time compared to the antiarrhythmic activity of an AAP, AAP10, HP5 isopeptide or analogue thereof. The term "antagonist" refers to an isopeptide which inhibits or antagonizes one or more physiological responses observed in a tissue, cell or cell fraction after contacting the tissue, cell or cell fraction with AAP, AAP10, HP5 isopeptide , or a functional analogue thereof. In one aspect, the physiological response is one or more of: contraction, relaxation, secretion, enzyme activation, etc. Preferably, the isopeptide is linked to the tissue, cells or cell fraction. In one aspect, the isopeptide is bound to a receptor in the tissue, cell or cell fraction which binds to AAP, AAP10, HP5, or a functional analogue thereof and / or which inhibits the binding of one or more of AAP, AAP10, HP5, a functional analogue thereof, to the receptor.

As used herein, "normalizes" refers to a chain in a physiological response such that the response begins insignificantly different from that observed in a normal patient. In this way, normalization may involve an increase or decrease in the response depending on the pathology involved. The "IC50" of an isopeptide according to the invention refers to the concentration of an isopeptide that is required for 50% inhibition of a response or activity mediated by an antiarrhythmic isopeptide such as AAP, AAP10, HP5 or a functional analogue of the same. In one aspect, an isopeptide which is an antagonist of AAP, AAP10, HP5 or a functional analogue thereof, is an isopeptide which has an IC50 of less than about 10 ~ 6M, and preferably, less than about 10 ~ 8 M. The "EC50" of an isopeptide according to the invention refers to the plasma / AUC concentration of isopeptide that is required to obtain 50% of a maximum effect observed for an AAP, AAP10, HP5 isopeptide or a functional analogue of the same. In one aspect, an isopeptide which is an agonist of AAP, AAP10, HP5 or a functional analogue thereof, is an isopeptide which has an EC50 of less than about 10"6M, and preferably, less than about 10" "8 M. As used herein," oral availability "refers to the relationship and extent of the absorption of a drug administered orally to the bloodstream The abbreviations used in the current application are further defined below.

Methyl (Me) - CH 3 Methoxy (MβO) - OCH 3 Ethyl (Et) - CHαCHα Ethoxy (EfO) - OCHαCHα n-Butyl (n-Bu) - CH 2 CH 2 CH 2 CH 3 n-Butoxy (n-BuO> -OOri ^ Cri ^^ n ^ Cri ^ n- Hexyl (n-Hßx) - CH? ^ CHzCHaCHzCHs n-Hexyloxy (n-HßxO) - OCH2CH CH2CH2CH2CH3 rt-? Ctyl (n-Oct) n-Octyloxy (n-OclO) - -OCH2CH2CH2CH2CHzCH2CH t-Butyl (l-Bu) cyclohexyl (o-He?) T cyclo-exoxy (C-HexO) 1 J Phenyl (Ph) ^ ^ phenoxy (PhO) "S02 Benzyl (Bzl) benzyloxy (BzlO) All references cited herein are incorporated by reference herein in their entirety. The variations, modifications and other implementations described herein may be presented to those of ordinary experience in the art without depending on the spirit and scope of the invention and the claims herein. It is noted that with this date, the best method known to the applicant to carry out the practice of said invention, is that which is clear from the present description of the invention.

Claims (32)

Claims: Having described the invention as above, the content of the following claims is claimed as property.

1. An isopeptide represented by the general formula (I): characterized in that, if a is 1 then b is 0; if a is 0 then b is 1; x and y independently are 1-7; Ri is H or CH3. R2 is a side chain of an amino acid selected from the group alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine and valina; R3 is selected from the group consisting of H, NH2, NHR, NR2, + NR3, OH, SH, RO, RS, RSO, RS02, COR, CSR, COOH, COOR, CONH2, CONHR, CONR2, OCOR and SCOR, where R = alkyl, alkenyl, aryl, aralkyl or cycloalkyl; and R4 and R5 are independently a hydrophobic group.

2. The isopeptide according to claim 1, characterized in that Rx is H.

3. The isopeptide according to claim 1 or claim 2, characterized in that R2 is the side chain of an amino acid selected from the group consisting of glycine and alanine.

4. The isopeptide according to any one of claims 1 to 3, characterized in that R3 is H or NH2.

5. The isopeptide according to any one of claims 1 to 4, characterized in that R4 and R5 independently comprise an aromatic carbon ring.

6. The isopeptide according to claim 5, characterized in that the aromatic ring comprises a ring of 6 or 12 members or a substituent thereof.

7. The isopeptide according to claim 6, characterized in that the ring is substituted with at least one of: a lower alkyl, alkoxy, hydroxyl, carboxy, amine, thiol, hydrazide, amide, halide, hydroxyl, ether, amine, nitrile, imine , nitro, sulfide, sulfoxide, sulfone, thiol, aldehyde, keto, carboxy, ester, an amide group; a selenium group, a thio group and derivatives thereof.

8. The isopeptide according to claim 6, characterized in that the aromatic ring is substituted with at least one of: a lower alkyl, alkoxy, halide, nitrile and nitro group.

9. The isopeptide according to claim 6, characterized in that the ring is substituted with at least one of: an alkoxy or nitro group.

10. The isopeptide according to claim 6, characterized in that the ring comprises about 1 to 5 substitutions.

11. The isopeptide according to claim 6, characterized in that the ring comprises about 1 to 2 substitutions.

12. The isopeptide according to claim 6, characterized in that the hydrophobic group is a 6-membered aromatic carbon ring comprising a substituent at the 4-position.

13. The isopeptide according to claim 12, characterized in that the substituent is selected from the group consisting of a methyl, ethyl, t-butyl, c-hexyl, phenyl, n-butyl, n-hexyl, n-octyl, ethoxy, t-butoxy, phenoxy, butoxy, benzyloxy, n-hexyloxy and n- group octyloxy.

14. The isopeptide according to claim 5, characterized in that the aromatic carbon ring is selected from the group consisting of a benzyl, phenyl and naphthyl group.

15. The isopeptide according to claim 14, characterized in that the aromatic carbon ring is a benzyl group.

16. The isopeptide according to any of claims 1 to 15, characterized in that Ri is H; R2 is the side chain of the glycine or alanine amino acid; R3 is H or NH2; R4 and R5 comprises a benzyl group substituted with at least one of a nitro or methoxy group.

17. An isopeptide represented by general formula II: characterized in that, if a = 1 then b = 0; if a = 0 then b = 1; x and y independently = 1-7; z = 1-6; q = 0-6; p = 0-1 Ri = H or CH3 R2 is the side chain of an amino acid selected from the group consisting of alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine; R3 is selected from the group consisting of H, NH2, NHR, NR2, + NR3, OH, SH, RO, RS, RSO, RS02, COR, CSR, COOH, COOR, CONH2, CONHR, CONR2, OCOR, and SCOR, wherein R = alkyl, alkenyl, aryl, aralkyl, or cycloalkyl; and R6 and R7 are independently selected from the group consisting of H, alkyl, alkenyl, aryl, aralkyl, halogen, CN, N0, alkoxy, aryloxy, aralkyloxy, thioalkoxy, thioaryloxy, thioaralkyloxy, + S (CH3) 2, S03H, S02R , NH2, NHR, NR2, + NR3, OH, SH, COOH, COOR, CONH2, CONHR, CONR2, CH2OH, NCO, NCOR, NHOH, NHNH2, NHNRH, CH2OCOR, CH2OCSR, COR, CSR, CSOR, CF3, and CC13 , and wherein R is alkyl, alkenyl, aryl, aralkyl, or cycloalkyl.

18. The isopeptide according to claim 17, characterized in that Ri is H.

19. The isopeptide according to claim 17 or claim 18, characterized in that R2 is the side chain of an amino acid selected from the group consisting of glycine and alanine.

20. The isopeptide according to any of claims 17 to 19, characterized in that R3 is H or NH2.

21. The isopeptide according to any of claims 17 to 19, characterized in that Rs and R7 are independently selected from the group consisting of H, alkyl, halogen, CN, N02, alkoxy and CF3.

22. The isopeptide according to claim 21, characterized in that R6 and R7 are independently selected from the group consisting of H, N02 and alkoxy.

23. The isopeptide according to any of claims 17 to 22, characterized in that Ri is H; R2 is the side chain of the glycine or alanine amino acid; R3 is H or NH2; R6 and R7 are independently selected from H, N02 and methoxy.

24. The isopeptide according to any of claims 1 to 23, characterized in that the isopeptide comprises a free N-terminal, a free C-terminal, or both a free N and C-terminal.

25. The isopeptide according to any of claims 1 to 24, characterized in that the isopeptide has a property selected from the group consisting of: binding to a hPepTl transporter or a biologically active fragment thereof; a half-life in an in vitro plasma stability test of more than about 30 minutes; an in vitro plasma stability test of more than about 48 hours; linkage to a tissue, cell, or cell fraction that is an action site for an arrhythmic peptide; modulate the function of the tissue, cell or cell fraction; antagonize the function of the antiarrhythmic peptide, agonize the function of the antiarrhythmic peptide, modulate the antiarrhythmic peptide receptor; and increase the time for AV block in a standard calcium-induced arrhythmia assay.

26. The peptide according to any of the preceding claims, characterized in that the isopeptide is selected from the group consisting of the isopeptides shown in Table 1 or Table 2.

27. A pharmaceutical composition, characterized in that it comprises the isopeptide defined in any of claims 1-26 and a pharmaceutical carrier.

28. The pharmaceutical composition according to claim 27, characterized in that the composition is administered parenterally or administered orally.

29. A method for modulating the space binding communication in a population of cells, characterized in that it comprises administering an effective amount of an isopeptide as defined in any of claims 1-26 for the population of cells thereby modulating the communication of union of space between cells.

30. The use of an isopeptide as defined in any of claims 1 to 26, for the manufacture of a medicament for the prevention and / or treatment of a pathological condition involving a damaged space junction communication comprising administering to a individual who needs a therapeutically effective amount thereof.

31. The use according to claim 30, wherein the administration is parenteral or oral.

32. The use according to claim 30, wherein the pathological condition is selected from the group consisting of a cardiovascular disease, airway epithelial inflammation, alveolar tissue disorders, bladder incontinence, hearing impairment, endothelial lesions, retinopathy diabetic, diabetic neuropathy, CNS, ischemia of the central nervous system, ischemia of the spinal cord, brain, brain root, spinal cord, dental tissue disorder, kidney disease, failure of bone marrow transplantation, wounds, erectile dysfunction, neuropathic pain, subchronic and chronic inflammation, cancer, transplant failure; a condition caused by an excess of species reactive to oxygen and / or free radicals and / or nitric oxide.