JP2020059663A - Peptides or pharmaceutically acceptable salts thereof or prodrugs thereof - Google Patents

Abstract

To provide short chain peptides having high myostatin inhibiting activities.SOLUTION: Disclosed is a peptide comprising an amino acid sequence of the following formula (1) as well as a pharmaceutically acceptable salt thereof or prodrugs thereof, where the number of amino acid residues of the peptide is 16 or less.SELECTED DRAWING: None

Description

  The present invention relates to a peptide or a pharmaceutically acceptable salt thereof, or a prodrug thereof.

  Muscular dystrophy is a hereditary disease in which muscle weakness progresses with skeletal muscle degeneration / necrosis as the main lesion. The expression of muscle force requires a mechanism for transmitting the tension generated in intracellular myofibrils to extracellular basement membranes through multiple proteins. Defects in the genes encoding the proteins involved in this cause the onset of muscular dystrophy. For example, in the most severe Duchenne muscular dystrophy, the dystrophin gene is mutated, and it is said that the main cause is a deletion or dysfunction of the protein. Therefore, as one means for combating degenerative necrosis of skeletal muscle in muscular dystrophy, muscle mass is inhibited by inhibiting the function of myostatin (growth differentiation factor-8, GDF-8), which is a factor that negatively regulates skeletal muscle mass. The development of therapeutics that increase thyroid gland is considered particularly useful.

  Myostatin is a secretory protein that belongs to the TGF-β family and is highly expressed in skeletal muscle, and is synthesized intracellularly as a precursor protein containing an N-terminal side pro domain and a C-terminal side mature domain. In myostatin secreted from cells, a propeptide derived from a prodomain called lateness associated protein (LAP) associates with an active dimer derived from the mature domain, and the active dimer, which is the main body that negatively regulates skeletal muscle mass, is not expressed. Activate. It is considered that myostatin, which is stocked in the living body in an inactivated state as described above, becomes an active body by proteolytic decomposition of the propeptide when necessary. The activated myostatin functions as a signal molecule that negatively regulates skeletal muscle mass through binding to a receptor represented by the activin type IIB receptor.

  Therefore, by inhibiting myostatin in vivo using a peptide derived from myostatin propeptide, effects such as an increase in skeletal muscle mass and treatment of muscular atrophic disorder represented by muscular dystrophy can be expected. For example, Patent Document 1 and Non-Patent Document 1 describe a myostatin inhibitor peptide derived from a myostatin propeptide.

International Publication No. 2014/119753

K. Takayama et al., Journal of Medicinal Chemistry (2015) 58, 1544-1549.

  Here, when the peptide as described above is used as a physiologically active agent such as a drug, it is advantageous to shorten the chain length (the number of residues of the peptide) from both aspects of synthesis and utilization in vivo. That is, by shortening the chain length of the peptide to be synthesized, it is possible to simplify the synthesis process and reduce the synthesis cost. In addition, shortening the chain length of the peptide can be expected to have the effect of reducing the number of sites that are decomposed by an enzyme or the like, and promoting the uptake into cells.

  However, conventionally, there has been a problem that if the chain length of a peptide derived from myostatin propeptide is reduced, the myostatin inhibitory activity tends to decrease. For example, as shown in FIG. 6 of Patent Document 1, in comparison with Peptide 1 having a long peptide chain length, SEQ ID NO: 2, Peptide 3 having a short chain length, SEQ ID NO: 4 in Peptide 3, has a myostatin inhibitory activity. Is falling. Also in FIG. 2 of Non-Patent Document 1, peptide 11 having a short chain length has a reduced myostatin inhibitory activity as compared with other peptides.

  Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a peptide having a short chain length, for example, having 16 or less amino acid residues and having high myostatin inhibitory activity. To do.

  The present inventors have conducted earnest research to solve the above problems. As a result, they have found that a peptide containing a predetermined amino acid sequence derived from follistatin solves the above-mentioned problems, and completed the present invention.

  One aspect of the present invention relates to a peptide comprising an amino acid sequence represented by the following formula (1) and having 16 or less amino acid residues, or a pharmaceutically acceptable salt thereof, or a prodrug thereof. .

In the above formula (1),
X ¹ is an amino acid residue or a defect selected from the group consisting of Val, Leu, Ile, norvaline, 2-aminobutyric acid, 2-cyclohexylglycine, 2-phenylglycine, norleucine and isovaline;
X ² is an amino acid residue selected from the group consisting of Asn, Gln, Asp and Glu;
X ³ is Glu or Asp;
X ⁴ is an amino acid residue selected from the group consisting of Asn, Asp, Glu and Gln;
X ⁵ is an amino acid residue selected from the group consisting of Ser, Thr, 2-hydroxyglycine and homoserine;
X ⁶ is Leu or 2-phenylglycine;
X ⁷ is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine, homophenylalanine, 2-cyclohexylglycine, Trp and Tyr;
X ⁸ is an amino acid residue selected from the group consisting of Lys, 2,4-diaminobutanoic acid, Arg, His, 2,3-diaminopropionic acid and ornithine;
X ⁹ is an amino acid residue selected from the group consisting of Phe, Trp, 3-naphthylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and homophenylalanine;
X ¹⁰ is selected from the group consisting of Met, Phe, norleucine, 3-thienylalanine, 2-phenylglycine, homophenylalanine, homomethionine, Val, Leu, Ile, 2-aminobutyric acid, norvaline, isovaline and 2-cyclohexylglycine. Is an amino acid residue that is
X ¹¹ is an amino acid residue selected from the group consisting of Ile, Val, norvaline, 2-cyclohexylglycine, 2-phenylglycine, Leu, 2-aminobutyric acid, norleucine and isovaline;
X ¹² is an amino acid residue selected from the group consisting of Phe, homophenylalanine, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine, 4-methoxyphenylalanine and 4-chlorophenylalanine. ;
X ¹³ is an amino acid residue selected from the group consisting of Asn, Gln, Asp and Glu; and X ¹⁴ consists of Gly, Ala, β-alanine, 4-aminobutyric acid, 2-aminoisobutyric acid and Pro. An amino acid residue or deletion selected from the group.

  According to the present invention, a peptide having high myostatin inhibitory activity and high myostatin selectivity can be provided.

5 shows myostatin inhibitory activity by the peptides of Examples and Comparative Examples. 5 shows the inhibitory activities of the peptides of Examples and Comparative Examples on myostatin, activin and TGF-β1. The result of the muscle mass of the anterior peroneus muscle of C57BL6J mouse | mouth after administering the peptide or albumin of an Example in both the anterior peroneus muscle of both legs, and breeding for 4 weeks is shown. 5 shows myostatin inhibitory activity by the peptides of Examples. 5 shows myostatin inhibitory activity by the peptides of Examples. 5 shows myostatin inhibitory activity by the peptides of Examples. 5 shows myostatin inhibitory activity by the peptides of Examples. 5 shows myostatin inhibitory activity by the peptides of Examples. 5 shows myostatin inhibitory activity by the peptides of Examples. 5 shows myostatin inhibitory activity by the peptides of Examples.

  Myostatin, which belongs to the TGF-β family, is known as a factor that negatively regulates muscle mass. It is generally known that myostatin is functionally inhibited by its interaction with its own prodomain protein or follistatin protein.

  The present inventors have surprisingly found that the peptide of SEQ ID NO: 6 derived from foliostatin (HFs41-54, the number of amino acid residues: 14), that is, the peptide of the present invention has a high myostatin inhibitory activity. I found it. Such a peptide can provide a peptide having a short chain length and high myostatin inhibitory activity.

  Further, the peptide according to the present invention has higher myostatin selectivity than peptide 7 described in Non-Patent Document 1 (see FIG. 2). Therefore, the peptide according to the present invention can further suppress the occurrence of side effects due to the inhibition of TGF-β family molecule.

  Hereinafter, an embodiment according to an aspect of the present invention will be described. The present invention is not limited to the following embodiments.

  In the present specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, operations and measurements of physical properties are performed under the conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50% RH.

  In the present specification, "a peptide containing the amino acid sequence represented by the formula (1) and having 16 or less amino acid residues, or a pharmaceutically acceptable salt thereof" is simply referred to as "the peptide according to the present invention". ".

  The “amino acid residue” in the present invention means a portion corresponding to one unit of amino acids constituting a peptide or protein on the peptide or protein molecule. More specifically, it means a divalent group derived from an α-amino acid represented by the following formula (2):

However, R ⁰ is a side chain of an amino acid, for example, a hydrogen atom for Gly and a methyl group for Ala.

The “amino acid residue” is derived from a natural or unnatural α-amino acid, and when it may have an optically active form, it may be either L form or D form, but L form is preferable. More specifically, “amino acid residue” means Arg, Lys, Asp, Asn, Glu, Gln, His, Pro, Tyr, Trp, Ser, Thr, Gly, Ala, Met, Cys, Phe, Leu, Val. , And Ile, and their analogs. The above analog may be, for example, a derivative in which the side chains of the above 20 kinds of amino acid residues are substituted with arbitrary substituents, and for example, a halogenated derivative of the above 20 kinds of amino acid residues (for example, , 3-chloroalanine, 4-fluorophenylalanine, 4-chlorophenylalanine), 2-aminobutyric acid, 4-aminobutyric acid, norleucine, norvaline, isovaline, 2-aminoisobutyric acid, homophenylalanine, 2,3-diaminopropionic acid, 2 , 4-Diaminobutanoic acid, ornithine, 2-hydroxyglycine, homoserine, hydroxylysine, hydroxyproline, 3,4-didehydroproline, homocysteine, homomethionine, aspartic acid ester (for example, aspartic acid-methyl ester, aspartic acid) -Ethyl ester, asparagus Acid-propyl ester, aspartic acid-cyclohexyl ester, aspartic acid-benzyl ester, etc.), glutamic acid ester (glutamic acid-cyclohexyl ester, glutamic acid-ethyl ester, glutamic acid-propyl ester, glutamic acid-methyl ester, glutamic acid-benzyl ester, etc.), Formyltryptophan, 2-cyclopentylglycine, 2-cyclohexylglycine, 2-phenylglycine, β-alanine, 3-cyclopentylalanine, 3-cyclohexylalanine, 3-pyridylalanine, 3-pyrazolylalanine, 3-furanylalanine, 3- Thienylalanine, 4-methoxyphenylalanine, and 3-naphthylalanine (3- (1-naphthyl) alanine, 3- (2-naphthyl) a) Examples thereof include amino acid residues derived from amino acids such as lanine), but are not limited thereto. Moreover, as for Ile and Thr, which have a diastereomer having an asymmetric carbon in the side chain, a natural type (for example, (2R ^* , 3R ^* )-2-amino-3-methylpentanoic acid, And (2R ^* , 3S ^* )-2-amino-3-hydroxybutanoic acid) and unnatural (eg, (2R ^* , 3S ^* )-2-amino-3-methylpentanoic acid, and (2R ^* , 3R ^* )-2-Amino-3-hydroxybutanoic acid) can be used without particular distinction. That is, "Ile" is used as a meaning including both (2R ^* , 3R ^* )-2-amino-3-methylpentanoic acid and (2R ^* , 3S ^* )-2-amino-3-methylpentanoic acid, "Thr" is used as a meaning including both (2R ^* , 3S ^* )-2-amino-3-hydroxybutanoic acid and (2R ^* , 3R ^* )-2-amino-3-hydroxybutanoic acid. Preferably. Natural diastereomers (ie (2R ^* , 3R ^* )-2-amino-3-methylpentanoic acid for Ile, (2R ^* , 3S ^* )-2-amino-3-hydroxybutane for Thr) Acid) is used.

  Unless otherwise specified, the amino acid sequences described in this specification are written in the direction from the N-terminal (amino terminal) side to the C-terminal (carboxyl terminal) side according to convention.

  It is known in the art that each amino acid residue can be replaced with an amino acid residue having similar properties based on the difference in its side chain (conservative substitution). For example, the aliphatic hydrophobic amino acids Val, Leu, Ile, 2-aminobutyric acid (Abu), norleucine (Nle), norvaline (Nva), and isovaline (Iva) can be substituted for each other. Gly, Ala, and 2-aminoisobutyric acid (Aib), whose side chains are hydrogen atoms or methyl groups, can be mutually substituted. Phe and homophenylalanine (Hph), whose side chains are phenylalkyl groups, can be substituted for each other. The neutral polar amino acids Asn and Gln may substitute for each other. The basic amino acids Arg, Lys, His, 2,3-diaminopropionic acid (Dpr), 2,4-diaminobutanoic acid (Dbu), and ornithine (Orn) can be substituted for each other. The acidic amino acids Asp and Glu may substitute for each other. Ser, 2-hydroxyglycine (Hyg) and homoserine (Hse), whose side chains are hydroxy groups or short-chain hydroxyalkyl groups, may be substituted with each other. Pro and 3,4-didehydroproline (Dhp) having a side chain having a structure in which the pyrrolidyl group of the side chain is dehydrogenated can be mutually substituted. Cys and homocysteine (Hcy), whose side chains are short-chain thiolalkyl groups, can substitute for each other. Met and homomethionine (Hme), whose side chains are short-chain sulfide structures, can substitute for each other. Trp, Tyr and Phe, whose side chains are aromatic, may substitute for each other.

  Furthermore, the amino acid residues Gly and Pro, which influence the orientation of the chains, can substitute for each other.

  As used herein, a "pharmaceutically acceptable salt" is a metal salt, ammonium salt, organic acid salt, inorganic acid salt, or organic salt that does not produce undesired physiological effects after being administered to a patient or subject. It is a salt with a base or an inorganic base. More specifically, sodium salt, potassium salt, calcium salt, magnesium salt, barium salt, aluminum salt, zinc salt, ammonium salt, methylamine salt, ethylamine salt, aniline salt, dimethylamine salt, diethylamine salt, pyrrolidine salt, Piperidine salt, morpholine salt, piperazine salt, trimethylamine salt, triethylamine salt, ethanolamine salt, diethanolamine salt, triethanolamine salt, hydrochloride, hydrobromide, nitrate, sulfate, phosphate, formate, acetate , Trifluoroacetate, phthalate, fumarate, oxalate, tartrate, maleate, citrate, succinate, malate, methanesulfonate, benzenesulfonate, and p- Examples thereof include toluene sulfonate, but are not limited to these.

  The prodrug of the peptide according to the present invention (hereinafter, the “prodrug of the peptide according to the present invention” is also simply referred to as “prodrug”) is a peptide derivative that is converted into the peptide according to the present invention, that is, gastric acid or enzyme. It refers to a peptide derivative that undergoes oxidation, reduction, hydrolysis, etc. to produce the peptide of the present invention. These peptide derivatives are described, for example, in Bundgard, H .; , Design of Prodrugs, pp. 7-9, 21-24, Elsevier, Amsterdam 1985 and the like, which are conventionally known methods, can be used to produce the peptide of the present invention.

  As the prodrug, when the side chain of the peptide according to the present invention has a carboxyl group, an ester derivative obtained by reacting the carboxyl group with an alcohol, or by reacting the carboxyl group with an amine The amide derivative obtained can be illustrated. More specifically, for example, a carboxyl group of a peptide side chain is represented by -COOR (R is an alkyl group having 1 to 20 carbon atoms), or -CONHR or -CONRR '(R and R'are Each independently includes a peptide derivatized with an amide group represented by an alkyl group having 1 to 20 carbon atoms).

  As the prodrug, when the side chain of the peptide according to the present invention has a hydroxyl group, an acyloxy derivative obtained by reacting the hydroxyl group with an acid anhydride or the like to be acylated can be exemplified. More specifically, for example, a peptide in which a hydroxyl group of a peptide side chain is derivatized to an acyloxy group represented by -OCOR (R is an alkyl group having 1 to 20 carbon atoms) can be mentioned.

When the side chain of the peptide of the present invention has an amino group, examples of the prodrug include derivatives in which the amino group is acylated, N-oxidized, alkylated, or phosphorylated. More specifically, for example, amino group -NHCOR side chain (R is an alkyl group having 1 to 20 carbon atoms) is or -NHCOCH _(NH 2) peptide derivatized to an amide group represented by CH ₃ Can be mentioned.

  The structure of the N-terminal of the peptide according to the present invention is not particularly limited, and may be, for example, a hydrogen atom (that is, unmodified) or a structure in which a modifying group is introduced by a conventionally known method. Examples of the N-terminal modifying group include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, an alkynyl group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and a heterocyclic group. A group represented by the following formula (3), a sulfonyl group, a carboxyl group, a glyoxyl group, a formyl group; a polyethylene glycol group (PEGylated), a polyoxyethylene glycol group, a polypropylene glycol group; a tert-butoxycarbonyl group (Boc group) ), Benzyloxycarbonyl group (Z group), fluorenylmethoxycarbonyl group (Fmoc group); cyclopentyloxycarbonyl group, cyclohexyloxycarbonyl group, adamantyloxycarbonyl group, norbornyloxycarbonyl group, iso Cycloalkyloxy such as bornyloxycarbonyl group Carbonyl group; carbamate protecting group; protecting groups derived from amino acids such as pyroglutamic acid or Morotan acid protecting group derived from a sulfonic acid or phosphoric acid, such as benzenesulfonic acid or the like, can be exemplified. Of these, from the viewpoint of myostatin inhibitory activity, the peptide has a N-terminal at which a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, a heterocyclic group, a group represented by the following formula (3), a sulfonyl group, a carboxyl group, It is preferably a glyoxyl group, a formyl group or a polyethylene glycol group, more preferably a hydrogen atom, an acyl group or a polyethylene glycol group, and even more preferably a hydrogen atom.

  The number of carbon atoms of the alkyl group that may be present at the N-terminal of the peptide is, for example, 1 to 20, and preferably 1 to 10. The alkyl group may have a saturated chain, unsaturated chain, or cyclic structure, and may have a branched chain structure. More specifically, the alkyl group includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a cyclopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an amyl group, an isoamyl group, and a tert group. Examples include -amyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group and decyl group.

  The number of carbon atoms of the aromatic hydrocarbon group that may be present at the N-terminal of the peptide is, for example, 6 to 20, and specific examples thereof include a phenyl group, a naphthyl group, a tolyl group, and a phenanthryl group. The heterocyclic group that may be present at the N-terminal of the peptide is a monocyclic, fused bicyclic or fused tricyclic group containing 1 to 3 heteroatoms selected from nitrogen atom, oxygen atom and sulfur atom in the ring. Examples of the substituents of the structure, more specifically, pyrrolidyl group, pyrrole group, piperidyl group, pyridyl group, imidazolyl group, pyrazolyl group, oxazolyl group, thiazolyl group, morpholyl group, indolyl group, benzimidazolyl group, quinolyl group, Examples thereof include a carbazolyl group, a tetrahydrofuranyl group, a tetrahydrothiophenyl group, a furanyl group, a thiophenyl group, a tetrahydropyranyl group, and a tetrahydrothiopyranyl group. These aromatic hydrocarbon groups and heterocyclic groups include linear or branched alkyl groups having 1 to 6 carbon atoms, linear or branched alkoxy groups having 1 to 6 carbon atoms, amino groups, carboxyl groups, esters. It may be substituted by further substituents such as groups, carbamoyl groups, amido groups, nitro groups, sulfo groups, sulfonamide groups, and / or halogens.

  The N-terminal modifying group may be, for example, a functional group represented by the following formula (3).

However, in equation (3),
X ⁰ is a single bond, an oxygen atom or a sulfur atom, or an alkylene having 1 to 3 carbon atoms, which may have a substituent selected from the group consisting of an amino group, an acetylamino group and a propionylamino group. A group (for example, a methylene group, an ethylene group, a trimethylene group and a propylene group), an oxyalkylene group having 1 to 3 carbon atoms (for example, an oxymethylene group, an oxyethylene group, an oxytrimethylene group and an oxypropylene group) and a carbon number 1 A divalent linking group selected from the group consisting of alkyleneoxy groups of 3 to 3 (for example, methyleneoxy group, ethyleneoxy group, trimethyleneoxy group and propyleneoxy group);
R ¹ is an alkyl group having 1 to 20 carbon atoms which may have a substituent, and

Selected from the group consisting of,
R ^{11 to} R ³⁰ are each independently a hydrogen atom, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group having 1 to 3 carbon atoms (that is, a methyl group, an ethyl group, a propyl group). ), An alkoxy group having 1 to 3 carbon atoms (that is, a methoxy group, an ethoxy group, a propoxy group), a hydroxyl group, and an amino group.

In the above formula (3), when R ¹ is an optionally substituted alkyl group having 1 to 20 carbon atoms, the fatty chain may be a saturated chain, an unsaturated chain, or a cyclic structure. Alternatively, it may have a branched chain structure. The alkyl group of R ¹ preferably has 2 to 12 carbon atoms.

The substituent of R ¹ includes a hydroxy group, an alkoxy group having 1 to 5 carbon atoms (eg, methoxy group, ethoxy group, etc.), amino group, carboxyl group, ester group, carbamoyl group, amide group, nitro group, sulfo group. And halogen (fluorine, chlorine, bromine, iodine) and the like.

In the above formula (3), X ⁰ is preferably a single bond, or may have a substituent selected from the group consisting of an amino group and an acetylamino group, and has 1 to 3 carbon atoms. It is a divalent linking group selected from the group consisting of an alkylene group and an oxyalkylene group having 1 to 3 carbon atoms.

  In one embodiment, the group represented by the above formula (3) is an acyl group. The acyl group includes acyl groups derived from various carboxylic acids. More specifically, it may be an acyl group having a fatty chain, an aromatic ring or a heterocyclic ring, or from a compound selected from the group consisting of an amino acid, a vitamin having an acyl group, and a nucleobase having an acyl group. It may be a derivatized acyl group.

More specifically, the acyl group in which R ¹ in the above formula (3) is an alkyl group having 1 to 20 carbon atoms which may have a substituent, more specifically, an acetyl group, a propionyl group, a butyryl group, an isobutyryl group. , Valeryl group, isovaler group, pivaloyl group, caproyl group, caprinoyl group, methylhexanoyl group, cyclopropanecarbonyl group, aminocyclopropanecarbonyl group, cyclohexanecarbonyl group, cyclohexylacetyl group, cyclopentylpropionyl group, cyclohexylpropionyl group, cyclopentylbutane group Noyl group, cyclohexylbutanoyl group, adamantylacetyl group, lauroyl group, myristoyl group, palmitoyl group, stearoyl group, oxalyl group, malonyl group, succinyl group, glutaryl group, adipoyl group, glycol group, la Examples include, but are not limited to, a tocoyl group, a glyceroyl group, a pyruvoyl group, an acetoacetyl group, and the like.

  Examples of vitamins having an acyl group include nicotinic acid, pantothenic acid, biotin, pteroylglutamic acid (folic acid), orotic acid, fluoroorotic acid, α-lipoic acid, pyridoxic acid, biocytin, pteroic acid, 10-formylpteroin. Acid, 7,8-dihydrofolic acid, homopteroic acid, pterin-6-carboxylic acid, dihydrolipoic acid, hydroorotic acid and the like can be mentioned.

  The nucleobase derivative having an acyl group refers to a base component constituting a nucleotide and its derivative, and preferably a pyrimidine derivative and the like, for example, 5-carboxymethyluracil, 5-carboxythiouracil and the like can be illustrated.

  Examples of the sulfonyl group that may be present at the N-terminal of the peptide include those having a structure in which the carbonyl structure of the acyl group described above is converted to a sulfone structure.

The polyethylene glycol group that may be present at the N-terminus of the peptide is a polyethylene glycol or an ester group, an amine (-NH-), an acyl group (for example, an acyl group having 1 to 12 carbon atoms), or the like, or a combination thereof. It is a structure in which the analog is linked. The number of carbon atoms of the polyethylene glycol group, for example 2 to 20 _{(i.e., - (C 2 H 4 O} ) n -. Has a structural unit represented by a n = 1 to 10), preferably 4 to 16 _{(i.e., - (C 2 H 4 O} ) n - it has the structural unit represented by, n = 2 to 8.) is. The end of the polyethylene glycol group opposite to the side connected to the N-terminal of the peptide is an alkyl group having 1 to 6 carbon atoms (for example, methyl group, ethyl group, propyl group, isopropyl group, cyclopropyl group, butyl group). Group, isobutyl group, sec-butyl group, tert-butyl group, amyl group, isoamyl group, tert-amyl group, hexyl group), modified with a protecting group or amino group commonly used for protecting hydroxyl groups. It may have been done.

The structure of the C-terminal of the peptide according to the present invention is not particularly limited, and may be a structure modified with a protecting group generally used for protecting carboxylic acid. More specifically, the structure of the C-terminus of the peptide according to the present invention, for example, a carboxyl group (-COOH), a carboxylate (-COO ^-), amide (-CONH _2), alkylamide (-CONHR ^31, - CONNR ³¹ R ³² ), an ester (-COOR ³¹ ), an acyloxyalkyl (-R ³³ -OCOR ³¹ ), such as a pivaloyloxymethyl group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group may be substituted. It may be a phthalidyl group (for example, a phthalidyl group, a dimethylphthalidyl group, a dimethoxyphthalidyl group) or a (5-methyl-2-oxo-1,3-dioxolen-4-yl) methyl group. Of these, the C-terminal of the peptide is preferably an amide. R ³¹ and R ³² in the above alkylamide, ester, and acyloxyalkyl are each independently a methyl group, an ethyl group, a propyl group, an isopropyl group, a cyclopropyl group, a butyl group, an isobutyl group, a sec-butyl group, or a tert group. -C1-C6 alkyl group such as butyl group, amyl group, isoamyl group, tert-amyl group, hexyl group, cyclohexyl group; C6-C10 aryl group such as phenyl group and naphthyl group; benzyl group, phenethyl group Group, aralkyl group having 7 to 18 carbon atoms such as benzhydryl group; sugar such as glucose; alkyl group having 1 to 6 carbon atoms (eg, methyl group, ethyl group, propyl group, isopropyl group, cyclopropyl group, butyl group, Isobutyl group, sec-butyl group, tert-butyl group, amyl group, isoamyl group tert- amyl group, etc. may polyethylene glycol group optionally modified with a hexyl group). R ³³ in the acyloxyalkyl is an alkylene group having 1 to 4 carbon atoms such as a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, an isobutylene group, an s-butylene group and a t-butylene group. Is.

  The peptides according to the present invention also include peptide derivatives chemically modified by covalent bonds with polymers, lipids, etc., and derivatives having a further enhanced α-helix property contained in the peptides. Examples of the derivative having further enhanced α-helix property include a derivative having a salt bridge formed at the i, i + 4 position and the like as an amino acid configuration, and a derivative having a crosslinked structure such as a disulfide bond or a carbon-carbon bond.

  The number of amino acid residues of the peptide according to the present invention is 16 or less. When the number of amino acid residues is 16 or less, it is advantageous in terms of both synthesis and utilization in vivo. The number of amino acid residues of the peptide according to the present invention is, for example, 12 to 16 residues, preferably 12 to 15 residues, more preferably 12 to 14 residues, and further preferably 13 to 14 residues. And particularly preferably 14 residues.

<Peptide>
According to one aspect of the present invention, a peptide comprising an amino acid sequence represented by the following formula (1) and having 16 or less amino acid residues, or a pharmaceutically acceptable salt thereof, or a prodrug thereof. Offer a drug:

In the above formula (1),
X ¹ is an amino acid residue or a defect selected from the group consisting of Val, Leu, Ile, norvaline, 2-aminobutyric acid, 2-cyclohexylglycine, 2-phenylglycine, norleucine and isovaline;
X ² is an amino acid residue selected from the group consisting of Asn, Gln, Asp and Glu;
X ³ is Glu or Asp;
X ⁴ is an amino acid residue selected from the group consisting of Asn, Asp, Glu and Gln;
X ⁵ is an amino acid residue selected from the group consisting of Ser, Thr, 2-hydroxyglycine and homoserine;
X ⁶ is Leu or 2-phenylglycine;
X ⁷ is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine, homophenylalanine, 2-cyclohexylglycine, Trp and Tyr;
X ⁸ is an amino acid residue selected from the group consisting of Lys, 2,4-diaminobutanoic acid, Arg, His, 2,3-diaminopropionic acid and ornithine;
X ⁹ is an amino acid residue selected from the group consisting of Phe, Trp, 3-naphthylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and homophenylalanine;
X ¹⁰ is selected from the group consisting of Met, Phe, norleucine, 3-thienylalanine, 2-phenylglycine, homophenylalanine, homomethionine, Val, Leu, Ile, 2-aminobutyric acid, norvaline, isovaline and 2-cyclohexylglycine. Is an amino acid residue that is
X ¹¹ is an amino acid residue selected from the group consisting of Ile, Val, norvaline, 2-cyclohexylglycine, 2-phenylglycine, Leu, 2-aminobutyric acid, norleucine and isovaline;
X ¹² is an amino acid residue selected from the group consisting of Phe, homophenylalanine, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine, 4-methoxyphenylalanine and 4-chlorophenylalanine. ;
X ¹³ is an amino acid residue selected from the group consisting of Asn, Gln, Asp and Glu; and X ¹⁴ consists of Gly, Ala, β-alanine, 4-aminobutyric acid, 2-aminoisobutyric acid and Pro. An amino acid residue or deletion selected from the group.

From the viewpoint of myostatin inhibitory activity, X ¹ is preferably an amino acid residue selected from the group consisting of Val, Leu, Ile, norvaline, 2-aminobutyric acid, 2-cyclohexylglycine, 2-phenylglycine, norleucine and isovaline. Is.

From the viewpoint of myostatin inhibitory activity, X ² is preferably Asn or Glu.

From the viewpoint of myostatin inhibitory activity, X ³ is preferably Asp.

From the viewpoint of myostatin inhibitory activity, X ⁴ is preferably an amino acid residue selected from the group consisting of Asn, Glu and Gln, more preferably Asn or Gln.

From the viewpoint of myostatin inhibitory activity, X ⁵ is preferably Thr.

From the viewpoint of myostatin inhibitory activity, X ⁶ is preferably Leu.

From the viewpoint of myostatin inhibitory activity, X ⁷ is preferably an amino acid residue selected from the group consisting of Phe, 3-thienylalanine, homophenylalanine and 2-cyclohexylglycine, more preferably Phe, 3-thienylalanine. And an amino acid residue selected from the group consisting of 2-cyclohexylglycine, more preferably Phe.

From the viewpoint of myostatin inhibitory activity, X ⁸ is preferably Lys.

From the viewpoint of myostatin inhibitory activity, X ⁹ is preferably an amino acid residue selected from the group consisting of Phe, Trp, 3- (2-naphthyl) alanine, 2-cyclohexylglycine, 4-fluorophenylalanine and homophenylalanine. is there.

From the viewpoint of myostatin inhibitory activity, X ¹⁰ is preferably Met, Phe, norleucine, 3-thienylalanine, 2-phenylglycine, homophenylalanine, homomethionine, Val, Leu, Ile, 2-aminobutyric acid, norvaline and isovaline. Is an amino acid residue selected from the group consisting of, more preferably Met, Phe, 3-thienylalanine, 2-phenylglycine, homophenylalanine and an amino acid residue selected from the group consisting of homomethionine, more preferably Is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine, 2-phenylglycine and homophenylalanine, particularly preferably from the group consisting of 3-thienylalanine, 2-phenylglycine and homophenylalanine. A selected amino acid residue.

From the viewpoint of myostatin inhibitory activity, X ¹¹ is preferably an amino acid residue selected from the group consisting of Ile, Val and 2-cyclohexylglycine.

From the viewpoint of myostatin inhibitory activity, X ¹² is preferably selected from the group consisting of Phe, homophenylalanine, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and 4-methoxyphenylalanine. It is an amino acid residue, more preferably an amino acid residue selected from the group consisting of Phe, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine and 4-fluorophenylalanine.

From the viewpoint of myostatin inhibitory activity, X ¹³ is preferably an amino acid residue selected from the group consisting of Asn, Gln and Asp.

From the viewpoint of myostatin inhibitory activity, X ¹⁴ is preferably an amino acid residue or a defect selected from the group consisting of Gly, Ala, β-alanine, 4-aminobutyric acid and 2-aminoisobutyric acid, and more preferably Gly. , Ala, β-alanine, 4-aminobutyric acid and 2-aminoisobutyric acid, and more preferably Gly, β-alanine and 4-aminobutyric acid. It is a residue.

In a preferred embodiment of the present invention, in the above formula (1),
X ¹ is an amino acid residue or a defect selected from the group consisting of Val, Leu, Ile, norvaline, 2-aminobutyric acid, 2-cyclohexylglycine, 2-phenylglycine, norleucine and isovaline;
X ² is an amino acid residue selected from the group consisting of Asn, Gln, Asp and Glu;
X ³ is Glu or Asp;
X ⁴ is an amino acid residue selected from the group consisting of Asn, Asp, Glu and Gln;
X ⁵ is an amino acid residue selected from the group consisting of Ser, Thr, 2-hydroxyglycine and homoserine;
X ⁶ is Leu or 2-phenylglycine;
X ⁷ is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine, homophenylalanine and 2-cyclohexylglycine;
X ⁸ is an amino acid residue selected from the group consisting of Lys, 2,4-diaminobutanoic acid, Arg, His, 2,3-diaminopropionic acid and ornithine;
X ⁹ is an amino acid residue selected from the group consisting of Phe, Trp, 3-naphthylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and homophenylalanine;
X ¹⁰ is an amino acid residue selected from the group consisting of Met, Phe, norleucine, 3-thienylalanine, 2-phenylglycine, homophenylalanine, homomethionine, Val, Leu, Ile, 2-aminobutyric acid, norvaline and isovaline. And
X ¹¹ is an amino acid residue selected from the group consisting of Ile, Val, norvaline, 2-cyclohexylglycine, 2-phenylglycine, Leu, 2-aminobutyric acid, norleucine and isovaline;
X ¹² is an amino acid residue selected from the group consisting of Phe, homophenylalanine, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and 4-methoxyphenylalanine;
X ¹³ is an amino acid residue selected from the group consisting of Asn, Gln, Asp and Glu; and X ¹⁴ is from the group consisting of Gly, Ala, β-alanine, 4-aminobutyric acid and 2-aminoisobutyric acid. The selected amino acid residue or deletion.

In a more preferred embodiment of the present invention, in the above formula (1),
X ¹ is an amino acid residue selected from the group consisting of Val, Leu, Ile, norvaline, 2-aminobutyric acid, 2-cyclohexylglycine, 2-phenylglycine, norleucine and isovaline;
X ² is an amino acid residue selected from the group consisting of Asn, Gln, Asp and Glu;
X ³ is Glu or Asp;
X ⁴ is an amino acid residue selected from the group consisting of Asn, Asp, Glu and Gln;
X ⁵ is an amino acid residue selected from the group consisting of Ser, Thr, 2-hydroxyglycine and homoserine;
X ⁶ is Leu or 2-phenylglycine;
X ⁷ is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine, homophenylalanine and 2-cyclohexylglycine;
X ⁸ is an amino acid residue selected from the group consisting of Lys, 2,4-diaminobutanoic acid, Arg, His, 2,3-diaminopropionic acid and ornithine;
X ⁹ is an amino acid residue selected from the group consisting of Phe, Trp, 3-naphthylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and homophenylalanine;
X ¹⁰ is an amino acid residue selected from the group consisting of Met, Phe, 3-thienylalanine, 2-phenylglycine, homophenylalanine and homomethionine;
X ¹¹ is an amino acid residue selected from the group consisting of Ile, Val, norvaline, 2-cyclohexylglycine, 2-phenylglycine, Leu, 2-aminobutyric acid, norleucine and isovaline;
X ¹² is an amino acid residue selected from the group consisting of Phe, homophenylalanine, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and 4-methoxyphenylalanine;
X ¹³ is an amino acid residue selected from the group consisting of Asn, Gln, Asp and Glu; and X ¹⁴ is from the group consisting of Gly, Ala, β-alanine, 4-aminobutyric acid and 2-aminoisobutyric acid. A selected amino acid residue.

In a further preferred embodiment of the present invention, in the above formula (1),
X ¹ is an amino acid residue selected from the group consisting of Val, Leu, Ile, norvaline, 2-aminobutyric acid, 2-cyclohexylglycine, 2-phenylglycine, norleucine and isovaline;
X ² is Asn or Glu;
X ³ is Asp;
X ⁴ is an amino acid residue selected from the group consisting of Asn, Glu and Gln;
X ⁵ is Thr;
X ⁶ is Leu;
X ⁷ is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine and 2-cyclohexylglycine;
X ⁸ is an amino acid residue selected from the group consisting of Lys, 2,4-diaminobutanoic acid, Arg, His, 2,3-diaminopropionic acid and ornithine;
X ⁹ is an amino acid residue selected from the group consisting of Phe, Trp, 3-naphthylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and homophenylalanine;
X ¹⁰ is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine, 2-phenylglycine and homophenylalanine;
X ¹¹ is an amino acid residue selected from the group consisting of Ile, Val and 2-cyclohexylglycine;
X ¹² is an amino acid residue selected from the group consisting of Phe, homophenylalanine, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and 4-methoxyphenylalanine;
X ¹³ is an amino acid residue selected from the group consisting of Asn, Gln and Asp; and X ¹⁴ is an amino acid residue selected from the group consisting of Gly, β-alanine and 4-aminobutyric acid.

In a particularly preferred embodiment of the present invention, in the above formula (1),
X ¹ is an amino acid residue selected from the group consisting of Val, Leu, Ile, norvaline, 2-aminobutyric acid, 2-cyclohexylglycine, 2-phenylglycine, norleucine and isovaline;
X ² is Asn or Glu;
X ³ is Asp;
X ⁴ is Asn or Gln;
X ⁵ is Thr;
X ⁶ is Leu;
X ⁷ is Phe;
X ⁸ is Lys;
X ⁹ is an amino acid residue selected from the group consisting of Phe, Trp, 3- (2-naphthyl) alanine, 2-cyclohexylglycine, 4-fluorophenylalanine and homophenylalanine;
X ¹⁰ is an amino acid residue selected from the group consisting of 3-thienylalanine, 2-phenylglycine and homophenylalanine;
X ¹¹ is an amino acid residue selected from the group consisting of Ile, Val and 2-cyclohexylglycine;
X ¹² is an amino acid residue selected from the group consisting of Phe, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine and 4-fluorophenylalanine;
X ¹³ is an amino acid residue selected from the group consisting of Asn, Gln and Asp; and X ¹⁴ is an amino acid residue selected from the group consisting of Gly, β-alanine and 4-aminobutyric acid.

  In the peptide according to the present invention, from the viewpoint of myostatin inhibitory activity, the peptide represented by the above formula (1) preferably contains any one of the amino acid sequences represented by SEQ ID NOs: 6 to 54, and more preferably Contains any one of the amino acid sequences represented by SEQ ID NOs: 6, 8 and 10-15, more preferably represented by SEQ ID NOs: 13, 15-33, 37, 39, 41, 42 and 45-54. Any one of the amino acid sequences represented by SEQ ID NOs: 17 to 19, 21 to 25, 27, 29 to 33, 41, 42, 45 to 49 and 51 to 53, which contains any one of the amino acid sequences. Including one.

<Method for producing peptide>
The peptide according to the present invention can be produced by a conventionally known method including a chemical synthesis method and a recombinant technique. In order to prepare a peptide by chemical synthesis, each amino acid is usually used in a method of peptide chemistry, for example, “The Peptides”, Vol. 1 [Schroder and Luhke, Academic Press, New York, U .; S. A. (1966)], "Basics and Experiments of Peptide Synthesis" (Nobuo Izumiya et al., Maruzen Co., Ltd., 1985) and the like, and can be produced by the liquid phase method and the solid phase method. It can be manufactured by either method. Further, either a column method or a batch method can be used.

  The peptide according to the present invention may also be produced by a recombinant technique using an animal cell, an insect cell, a microorganism or the like, for example, by the method described in the following Current Protocols in Molecular Biology, Chapter 16. The peptide can be purified by a conventionally known method after being produced by cultured cells or microorganisms. Methods for purifying and isolating peptides are known to those skilled in the art, and can be performed by the methods described in, for example, Current Protocols in Molecular Biology, Chapter 16 (Ausubel et al., John Wiley and Sons, 2006).

  As a condensation method for forming a peptide bond, an azide method, an acid halide method, an acid anhydride method, a carbodiimide method, a carbodiimide-additive method, an active ester method, a carbonylimidazole method, a redox method, an enzymatic method, a Woodward reagent K , HATU reagent, Bop reagent, and the like. Among the above-mentioned methods, the condensation reaction in the solid phase method is mainly the acid anhydride method, the carbodiimide method, and the active ester method.

  Furthermore, when the peptide chain is extended by the solid phase method, the C-terminal amino acid is bound to a support such as a resin that is insoluble in the organic solvent used. As such a resin, a resin in which a functional group is introduced for the purpose of binding an amino acid to the resin, a resin in which a spacer is inserted between the resin and a functional group, or the like can be used depending on the purpose. More specifically, for example, halomethyl resin such as chloromethyl resin, oxymethyl resin, 4- (oxymethyl) -phenylacetamidomethyl resin, 4- (oxymethyl) -phenoxymethyl resin, Rink amide resin and the like can be mentioned. You can Before carrying out these condensation reactions, it is possible to provide a means for protecting carboxyl groups, amino groups, hydroxyl groups, amidino groups, etc., which are not involved in the condensation reaction, by a generally known means. Conversely, it is also possible to activate the carboxyl group and amino group that are directly involved in the condensation reaction.

  The protecting group used for protecting the functional group not involved in the condensation reaction of each unit is a protecting group usually used in organic chemistry, for example, “Protective Groups in Organic Synthesis (Greene, John Wiley & Sons, Inc. 1981)) and the like. More specifically, examples of the protecting group for the carboxyl group include various methyl esters, ethyl esters, benzyl esters, p- Examples thereof include commonly known protecting groups such as nitrobenzyl ester, t-butyl ester, cyclohexyl ester, etc. Examples of the protecting group for amino group include benzyloxycarbonyl group, t-butoxycarbonyl group and isobornyloxycarbo group. Examples thereof include a nyl group and a 9-fluorenylmethoxycarbonyl group (Fmoc group).

  As the activated carboxyl group, for example, an acid anhydride corresponding to the carboxyl group; azide; pentafluorophenol, 2,4-dinitrophenol, cyanomethyl alcohol, p-nitrophenol, N-hydroxysuccinic acid Examples thereof include active esters with imide, N-hydroxy-5-norbornene-2,3-dicarboximide, N-hydroxyphthalimide, 1-hydroxybenzotriazole and the like. Examples of activated amino groups include phosphoric acid amides corresponding to the amino groups.

  The condensation reaction during peptide synthesis is usually performed in a solvent. Examples of the solvent include chloroform, dichloromethane, ethyl acetate, N, N-dimethylformamide, dimethylsulfoxide, pyridine, dioxane, tetrahydrofuran, N-methylpyrrolidone, water, methanol, and the like, or a mixture thereof. . The reaction temperature of the condensation reaction can be carried out in the range of -30 ° C to 50 ° C, as in the usual case.

  Further, the type of the protective group elimination reaction in the production process of the peptide of the present invention is selected according to the type of the protective group used, as long as the protective group can be eliminated without affecting the peptide bond. be able to. For example, acid treatment with hydrogen chloride, hydrogen bromide, anhydrous hydrogen fluoride, methanesulfonic acid, trifluoromethanesulfonic acid, trifluoroacetic acid, or a mixture thereof, sodium hydroxide, potassium hydroxide, hydrazine, diethylamine, piperidine, etc. Examples of the treatment include alkali treatment with sodium chloride, sodium treatment in liquid ammonia, reduction with palladium carbon, and silylation treatment with trimethylsilyl triflate, trimethylsilyl bromide and the like. In the deprotection group reaction by the above-mentioned acid or silylating agent treatment, addition of a cation trapping agent such as anisole, phenol, cresol, thioanisole, and ethanedithiol enables the deprotection group reaction to be carried out efficiently. It is preferable from the viewpoint.

  In addition, the method for cleaving the peptide of the present invention synthesized by the solid phase method from the solid phase also follows a generally known method. For example, treatment with the above-mentioned acid or silylating agent can be cited as the cutting method. For the peptide of the present invention thus produced, generally known separation and purification means can be used after completion of the above series of reactions. For example, the peptide of the present invention can be obtained in higher purity by extraction, partitioning, reprecipitation, recrystallization, solid phase extraction, column chromatography and the like.

  The obtained peptide can be analyzed by an amino acid automatic analyzer, capillary electrophoresis, reverse phase high performance liquid chromatography, mass spectrometry and the like. In addition, various biomolecular interaction analysis methods such as phage display method, two-hybrid method, affinity chromatography, surface plasmon resonance method, co-immunoprecipitation method, protein chip method, three-dimensional structure analysis, far western method, fluorescence quenching method, etc. are used. Alternatively, the peptides may be selected using the interaction with myostatin as an index.

  The peptide according to the present invention may be isolated or purified. The "isolation or purification" means that an operation for removing components other than the target component has been performed. The purity of the isolated or purified peptide of the present invention is usually 50% or higher (eg, 70% or higher, 80% or higher, 90% or higher, 95% or higher, 98% or higher, 99% or higher, 100%). is there.

<Myostatin inhibitor, prophylactic / therapeutic agent, preventive method / therapeutic method>
In one embodiment of the present invention, a myostatin inhibitor comprising the peptide of the present invention or a prodrug thereof is provided (hereinafter, referred to as "myostatin inhibitor containing the peptide of the present invention or a prodrug thereof," Also referred to simply as "myostatin inhibitor"). By administering an effective amount of the above-mentioned myostatin inhibitor to a subject, effects such as the maintenance, increase, enhancement, and reduction of muscle mass and muscle strength can be achieved. The myostatin inhibitor may be composed of one or more peptides of the present invention, or one or more prodrugs thereof, or a mixture thereof. A pharmaceutical composition comprising one or more selected and a pharmaceutically acceptable carrier.

  One embodiment of the present invention relates to a method for inhibiting myostatin, comprising administering to a patient an effective amount of a peptide of the present invention or a prodrug thereof. One embodiment of the invention also relates to a peptide of the invention or a prodrug thereof for use in inhibiting myostatin.

  In one embodiment of the present invention, there is provided a preventive and / or therapeutic agent for muscular atrophy disorder, which comprises the peptide of the present invention or a prodrug thereof (hereinafter, referred to as “muscle containing the peptide of the present invention or a prodrug thereof”). The "prophylactic and / or therapeutic agent for atrophy disorder" is also simply referred to as "prophylactic / therapeutic agent for muscular atrophy disorder"). By administering an effective amount of the preventive / therapeutic agent for the muscular atrophy disorder to a patient, the therapeutic effect such as slowing down the progression rate of the muscular atrophy disorder, inhibiting the progress, stopping the progress, improving, healing, and / or preventing Can be achieved. The preventive / therapeutic agent for muscular atrophy disorder may be composed of one or more peptides of the present invention, or one or more prodrugs thereof, or a mixture thereof. A pharmaceutical composition comprising one or more selected from prodrugs thereof and a pharmaceutically acceptable carrier.

  One embodiment of the present invention relates to a method for preventing and / or treating a muscular atrophy disorder, which comprises administering an effective amount of the peptide of the present invention or a prodrug thereof to a patient. One embodiment of the present invention also relates to a peptide of the present invention or a prodrug thereof for use in the prevention and / or treatment of muscular atrophy disorder.

  The myostatin inhibitor, the prophylactic / therapeutic agent for muscular atrophy disorder, and the above-mentioned preventive and / or therapeutic method are also effective for strengthening the tibialis anterior muscle by local administration for elderly people who usually have impaired gait. Even if only the tibialis anterior muscle is strengthened, dorsiflexion of the ankle joint will be easy and will help prevent falls. Further, for example, if continuous local administration can be carried out during a stay in space, it can contribute to shortening the rehabilitation period after returning.

  The above-mentioned muscular atrophy disorder is not particularly limited, for example, muscular dystrophy, distal myopathy, congenital myopathy, inflammatory myopathy such as inclusion body myositis, myopathy such as mitochondrial myopathy; disused muscle atrophy. Sarcopenia etc. can be illustrated. More preferably, the prophylactic / therapeutic agent for muscular atrophy disorder is Duchenne muscular dystrophy, Becker muscular dystrophy, Fukuyama congenital muscular dystrophy, merosin deficient congenital muscular dystrophy, limb type muscular dystrophy, facial scapulohumeral muscular dystrophy, emery dreyfus It is effectively used for muscular dystrophy such as muscular dystrophy of type 3, Miyoshi muscular dystrophy, and infantile axonal muscular dystrophy. Among them, it is particularly effective for Duchenne muscular dystrophy.

  Amyotrophic disorders can also result from chronic diseases such as amyotrophic lateral sclerosis, chronic obstructive pulmonary disease (COPD), cancer, AIDS, renal failure, and rheumatoid arthritis. Muscle wasting disorders can also result from metabolic disorders such as diabetes and related disorders. Therefore, the preventive / therapeutic agent for muscular atrophy disorder of the present invention and the above-mentioned preventive and / or therapeutic method can be used for improving cachexia accompanied by muscle atrophy. In addition, inhibition of myostatin can improve bone strength and reduce osteoporosis and other degenerative bone diseases with increased muscle mass.

  As used herein, a therapeutically "effective amount" is an amount effective to produce some desired therapeutic effect, which is commensurate with the reasonable benefit / risk ratio.

  In the present specification, the “subject” and “patient” include non-human animals including humans and fish, but preferably humans, dogs, cats, mice, rats, hamsters, guinea pigs, horses (racing horses). (Including), mammals such as cows, pigs, rabbits, and sheep, and poultry such as chickens, quails, and turkeys, and more preferably humans.

  The above-mentioned pharmaceutically acceptable carriers are not particularly limited, but excipients such as lactose, sucrose, mannitol, starch, corn starch, crystalline cellulose, light anhydrous silicic acid; silica, talc, calcium stearate, stearic acid. Lubricants such as magnesium; hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, carboxymethylcellulose sodium, methylcellulose, polyvinylpyrrolidone, crystalline cellulose, dextrin, gelatin, etc. binders; ascorbic acid, sodium sulfite, sodium bisulfite, tocopherol, etc. Antioxidants of ethylene; chelating agents such as ethylenediaminetetraacetic acid (EDTA); buffers of borate, bicarbonate, Tris-HCl, citrate, phosphate, other organic acids, etc. Water for injection, physiological saline, ethanol, propanol, ethylene glycol, propylene glycol, macrogol, solvents such as olive oil and corn oil; Pluronic (registered trademark), polyethylene glycol, sorbitan fatty acid ester, polysorbate, Triton (registered trademark), Surfactants or wetting agents such as lecithin, cholesterol, benzalkonium chloride, benzethonium chloride, glycerin monostearate; isotonic agents such as sodium chloride, potassium chloride, glycerin, glucose, sorbitol, mannitol; benzoic acid, salicylic acid, Preservatives such as thimerosal, phenethyl alcohol, methylparaben, propylparaben, chlorhexidine; complexing agents; amino acids; antibacterial agents; coloring agents; flavoring agents and diluents; emulsifiers; Transport vehicle; salt-forming counterions such as beam such as diluting agents (Remington's Pharmaceutical Sciences, 18th Edition, A. R. Gennaro eds, Mack Publishing Company, 1990).

  The content of the peptide of the present invention or a prodrug thereof in the drug may be 0.01 to 100% by weight based on the whole drug.

  The dose of the compound of the present invention varies depending on the age, symptoms, administration method, etc., but when administered orally, it is generally about 0.1 to 100 mg per day for a human (60 kg body weight). , Preferably about 1.0 to 50 mg, more preferably about 1.0 to 20 mg. When administered parenterally, the single dose varies depending on age, symptoms, administration method, etc., but, for example, in the form of an injection, it is usually administered to a human (60 kg body weight) per day. It is convenient to administer about 0.01 to 30 mg, preferably about 0.1 to 20 mg, and more preferably about 0.1 to 10 mg. Also in the case of animals other than humans, the dose converted per 60 kg of body weight can be administered.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples.

<Synthesis of peptide>
(Synthesis example 1)
Peptide containing the amino acid sequence of SEQ ID NO: 6: Synthesis of HFs41-54 VNDNTLFKWMIFNG-NH ₂ (HFs41-54)
HFs41-54 was synthesized by the Fmoc solid phase peptide synthesis method shown below.

54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) was set in a weighing device in a reaction vessel for a Prelude 6-channel peptide synthesizer (Protein Technologies). The following reactions were all performed under a nitrogen atmosphere. After swelling the resin in a dimethylformamide (DMF) solution at room temperature (25 ° C.) for 30 minutes, in a 20% (v / v) piperidine / DMF solution (2.5 mL) at room temperature (25 ° C.) for 5 minutes 2 The protective group Fmoc (9-fluorenylmethoxycarbonyl) group on the resin was removed by carrying out a cycle reaction. The resin was washed 6 times with DMF (2.5 mL), 1-hydroxy-7-azabenzotriazole (HOAt, 0.20 mmol, 10 eq.), O- (7-aza-1H-benzotriazol-1-yl). In the presence of —N, N, N ′, N′-tetramethyluronium hexafluorophosphate (HATU, 0.20 mmol, 10 eq.) And N, N-diisopropylethylamine (DIEA, 0.20 mmol, 10 eq), Fmoc -Gly-OH (0.20 mmol, 10 eq.) Was reacted in DMF (2 mL) at room temperature (25 ° C) for 30 minutes to introduce an amino acid onto the resin. In order to condense the next amino acid, the Fmoc group on the resin was removed by performing 2 cycles of reaction in a 20% (v / v) piperidine / DMF solution (2.5 mL) for 5 minutes. Hereinafter, in the same manner as in the case of Fmoc-Gly-OH, Fmoc-Asn (Trt) -OH (0.20 mmol, 10 eq.), Fmoc-Phe-OH (0.20 mmol, 10 eq.), And Fmoc from the C terminal side in order. -Ile-OH (0.20 mmol, 10 eq.), Fmoc-Met-OH (0.20 mmol, 10 eq.), Fmoc-Trp (Boc) -OH (0.20 mmol, 10 eq.), Fmoc-Lys (Boc). -OH (0.20 mmol, 10 eq.), Fmoc-Phe-OH (0.20 mmol, 10 eq.), Fmoc-Leu-OH (0.20 mmol, 10 eq.), Fmoc-Thr (tBu) -OH (0. 20 mmol, 10 eq.), Fmoc-Asn (Trt) -OH (0.20 mmol, 10 eq. ), Fmoc-Asp (OtBu) -OH (0.20 mmol, 10 eq.), Fmoc-Asn (Trt) -OH (0.20 mmol, 10 eq.), Fmoc-Val-OH (0.20 mmol, 10 eq.). It was introduced to extend the peptide chain. The N-terminal Fmoc group was removed by reacting in a 20% (v / v) piperidine / DMF solution (2.5 mL) for 2 cycles for 5 minutes to remove DMF (2.5 mL, 6 times) and methanol (2.5 mL). , 5 times), the resin was dried by nitrogen purging. For removal of various side chain protecting groups and resin removal, trifluoroacetic acid (TFA) was added in the presence of m-cresol (0.125 mL), thioanisole (0.125 mL) and 1,2-ethanedithiol (0.050 mL). The reaction was carried out in 5.0 mL for 2 hours. After removing the resin by filtration using a funnel with a glass filter, TFA was distilled off under reduced pressure by a rotary evaporator, and 40 mL of diethyl ether was added to precipitate a crudely purified peptide. The crude peptide was dissolved in 1M acetic acid and purified by high performance liquid chromatography to obtain a white solid (17.2 mg, yield 47.5%).
HRMS (ES +): m / z 1697.8496 (M + H ⁺ ) (calculated: 16977.8474).

(Synthesis example 2)
Peptide comprising the amino acid sequence of SEQ ID NO: 7: Synthesis of HFs42-53 _{NDNTLFKWMIFN-NH} 2 (HFs42-53)
HFs42-53 was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (8.0 mg, yield 24. 3%).
HRMS (ES +): m / z 1541.7527 (M + H ⁺ ) (calculated: 1541.7575).

(Synthesis example 3)
Peptide containing the amino acid sequence of SEQ ID NO: 8: Synthesis of G54A VNDNTLFKWMIFNA-NH ₂ (G54A)
G54A was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (1.8 mg, yield 4.8%). ).
HRMS (ES +): m / z 1711.8654 (M + H ⁺ ) (calculated: 1711.8630).

(Synthesis example 4)
Peptide containing amino acid sequence of SEQ ID NO: 9: Synthesis of M50Nle VNDNTLFKW-Nle-IFNG-NH ₂ (M50Nle)
Nle: Norleucine M50Nle was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (7.2 mg, yield 20). 0.0%).
HRMS (ES +): m / z 1679.8926 (M + H ⁺ ) (calculated: 1679.8910).

(Synthesis example 5)
Peptide comprising the amino acid sequence of SEQ ID NO: 10: Synthesis of _{M50Thi VNDNTLFKW-Thi-IFNG-NH} 2 (M50Thi)
Thi: 3-thienylalanine M50Thi was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (10.2 mg, Yield 27.9%).
HRMS (ES +): m / z 1719.8318 (M + H ⁺ ) (calculated: 1719.8317).

(Synthesis example 6)
Peptide containing the amino acid sequence of SEQ ID NO: 11: Synthesis of T45S VNDNSLFKW-Thi-IFNG-NH ₂ (T45S)
Thi: 3-thienylalanine T45S was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (18.8 mg, Yield 51.7%).
LRMS (MALDI +): m / z 1705.88 (M + H ⁺ ) (calculated: 1705.82).

(Synthesis example 7)
Peptide containing the amino acid sequence of SEQ ID NO: 12: Synthesis of L46Phg VNDNT-Phg-FKW-Thi-IFNG-NH ₂ (L46Phg)
Phg: 2-phenylglycine L46Phg was synthesized and purified by the same method as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (2.3 mg, Yield 6.2%).
LRMS (MALDI +): m / z 1740.26 (M + H ⁺ ) (calculated: 1739.80).

(Synthesis example 8)
Peptide comprising the amino acid sequence of SEQ ID NO: 13: Synthesis of _{F47Thi VNDNTL-Thi-KW-Thi} -IFNG-NH 2 (F47Thi)
Thi: 3-thienylalanine F47Thi was synthesized and purified by the same method as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (2.1 mg, Yield 5.7%).
LRMS (MALDI +): m / z 1725.67 (M + H ⁺ ) (calculated: 1725.79).

(Synthesis example 9)
Peptide comprising the amino acid sequence of SEQ ID NO: 14: Synthesis of _{F47Hph VNDNTL-Hph-KW-Thi} -IFNG-NH 2 (F47Hph)
Hph: Homophenylalanine F47Hph was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (20.0 mg, yield). 54.2%).
LRMS (MALDI +): m / z 1733.51 (M + H ⁺ ) (calculated: 173.85).

(Synthesis example 10)
A peptide containing the amino acid sequence of SEQ ID NO: 15: Synthesis of F47Chg VNDNTL-Chg-KW-Thi-IFNG-NH ₂ (F47Chg)
Chg: 2-cyclohexylglycine F47Chg was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (21.8 mg, Yield 59.8%).
LRMS (MALDI +): m / z 1711.26 (M + H ⁺ ) (calculated: 1711.86).

(Synthesis example 11)
Peptide containing the amino acid sequence of SEQ ID NO: 16: Synthesis of W49 (1-Nal) VNDNTLFK- (1-Nal) -Thi-IFNG-NH ₂ (W49 (1-Nal))
1-Nal: 3- (1-naphthyl) alanine W49 (1-Nal) was the same as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.). Synthesized and purified by the method (8.0 mg, yield 21.7%).
LRMS (MALDI +): m / z 1730.32 (M + H ⁺ ) (calculated: 1730.84).

(Synthesis example 12)
Peptide containing the amino acid sequence of SEQ ID NO: 17: Synthesis of W49 (2-Nal) VNDNTLFK- (2-Nal) -Thi-IFNG-NH ₂ (W49 (2-Nal))
2-Nal: 3- (2-naphthyl) alanine W49 (2-Nal) was the same as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.). Synthesized and purified by the method (4.2 mg, yield 11.4%).
LRMS (MALDI +): m / z 1730.65 (M + H ⁺ ) (calculated: 1730.84).

(Synthesis example 13)
Peptide containing the amino acid sequence of SEQ ID NO: 18: Synthesis of W49F VNDNTLFKF-Thi-IFNG-NH ₂ (W49F)
Thi: 3-thienylalanine W49F was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (5.1 mg, Yield 14.2%).
LRMS (MALDI +): m / z 1681.57 (M + H ⁺ ) (calculated: 1680.82).

(Synthesis example 14)
Peptide containing the amino acid sequence of SEQ ID NO: 19: Synthesis of W49Chg VNDNTLFK-Chg-Thi-IFNG-NH ₂ (W49Chg)
Chg: 2-cyclohexylglycine W49Chg was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (16.6 mg, Yield 46.1%).
LRMS (MALDI +): m / z 1686.96 (M + H ⁺ ) (calculated: 1686.87).

(Synthesis example 15)
Peptide containing the amino acid sequence of SEQ ID NO: 20: Synthesis of M50F VNDNTLFKWFIFNG-NH ₂ (M50F)
M50F was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (16.5 mg, 45.2%).
LRMS (MALDI +): m / z 1713.01 (M + H ⁺ ) (calculated: 1713.88).

(Synthesis example 16)
Peptide containing the amino acid sequence of SEQ ID NO: 21: Synthesis of M50Phg VNDNTLFKW-Phg-IFNG-NH ₂ (M50Phg)
Phg: 2-phenylglycine M50Phg was synthesized and purified by the same method as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (11.8 mg, Yield 32.6%).
LRMS (MALDI +): m / z 1700.59 (M + H ⁺ ) (calculated: 1699.86).

(Synthesis example 17)
Peptide containing the amino acid sequence of SEQ ID NO: 22: Synthesis of M50Hph VNDNTLFKW-Hph-IFNG-NH ₂ (M50Hph)
Hph: Homophenylalanine M50Hph was synthesized and purified by the same method as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) (10.7 mg, yield). 29.1%).
LRMS (MALDI +): m / z 1727.68 (M + H ⁺ ) (calculated: 1727.89).

(Synthesis example 18)
Peptide comprising the amino acid sequence of SEQ ID NO: 23: Synthesis of _{F52Thi VNDNTLFKW-Thi-I-Thi} -NG-NH 2 (F52Thi)
Thi: 3-thienylalanine F52Thi was synthesized and purified by the same method as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (14.0 mg, Yield 38.1%).
LRMS (MALDI +): m / z 1726.59 (M + H ⁺ ) (calculated: 172.79).

(Synthesis example 19)
Peptide comprising the amino acid sequence of SEQ ID NO 24: F52Phe (4-F) Synthesis _{VNDNTLFKW-Thi-I-Phe (} 4-F) -NG-NH 2 (F52Phe (4-F))
Thi: 3-thienylalanine Phe (4-F): 4-fluorophenylalanine F52Phe (4-F) was synthesized using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.). Synthesized and purified in the same manner as in Example 1 (14.8 mg, yield 40.0%).
LRMS (MALDI +): m / z 1737.05 (M + H ⁺ ) (calculated: 1737.82).

(Synthesis example 20)
A peptide containing the amino acid sequence of SEQ ID NO: 25: Synthesis of F52Phg VNDNTLFKW-Thi-I-Phg-NG-NH ₂ (F52Phg)
Thi: 3-thienylalanine Phg: 2-phenylglycine F52Phg was synthesized and purified in the same manner as in Synthesis Example 1 by using Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) 54 mg (0.020 mmol). (11.0 mg, yield 30.3%).
LRMS (MALDI +): m / z 1705.30 (M + H ⁺ ) (calculated: 1705.82).

(Synthesis example 21)
A peptide containing the amino acid sequence of SEQ ID NO: 26: Synthesis of F52Hph VNDNTLFKW-Thi-I-Hph-NG-NH ₂ (F52Hph)
Thi: 3-thienylalanine Hph: homophenylalanine F52Hph was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) ( 15.3 mg, yield 41.4%).
LRMS (MALDI +): m / z 1733.09 (M + H ⁺ ) (calculated: 173.85).

(Synthesis example 22)
A peptide containing the amino acid sequence of SEQ ID NO: 27: Synthesis of F52Chg VNDNTLFKW-Thi-I-Chg-NG-NH ₂ (F52Chg)
Thi: 3-thienylalanine Chg: 2-cyclohexylglycine F52Chg was synthesized and purified by the same method as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.). (15.3 mg, yield 41.9%).
LRMS (MALDI +): m / z 1712.10 (M + H ⁺ ) (calculated: 1711.86).

(Synthesis example 23)
A peptide containing the amino acid sequence of SEQ ID NO: 28: Synthesis of V41Abu (2) Abu-NDNTLFKW-Thi-IFNG-NH ₂ (V41Abu (2))
Abu: 2-aminobutyric acid Thi: 3-thienylalanine V41Abu (2) was prepared by the same method as in Synthesis Example 1 using Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) 54 mg (0.020 mmol). Synthesized and purified (7.8 mg, yield 21.5%).
LRMS (MALDI +): m / z 1705.72 (M + H ⁺ ) (calculated: 1705.82).

(Synthesis example 24)
A peptide containing the amino acid sequence of SEQ ID NO: 29: Synthesis of V41Nva Nva-NDNTLFKW-Thi-IFNG-NH ₂ (V41Nva)
Nva: norvaline Thi: 3-thienylalanine V41Nva was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (10 0.1 mg, yield 27.6%).
LRMS (MALDI +): m / z 1719.56 (M + H ⁺ ) (calculated: 1719.83).

(Synthesis example 25)
A peptide containing the amino acid sequence of SEQ ID NO: 30: Synthesis of V41I INDNTLFKW-Thi-IFNG-NH ₂ (V41I)
Thi: 3-thienylalanine V41I was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (6.8 mg, Yield 18.4%).
LRMS (MALDI +): m / z 1734.20 (M + H ⁺ ) (calculated: 173.85).

(Synthesis example 26)
Peptide containing the amino acid sequence of SEQ ID NO: 31: Synthesis of V41L LNDNTLFKW-Thi-IFNG-NH ₂ (V41L)
Thi: 3-thienylalanine V41L was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (11.4 mg, Yield 30.9%).
LRMS (MALDI +): m / z 1733.65 (M + H ⁺ ) (calculated: 173.85).

(Synthesis example 27)
Peptide containing the amino acid sequence of SEQ ID NO: 32: Synthesis of V41Chg Chg-NDNTLFKW-Thi-IFNG-NH ₂ (V41Chg)
Chg: 2-cyclohexylglycine Thi: 3-thienylalanine V41Chg was synthesized and purified by the same method as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.). (21.7 mg, yield 58.0%).
LRMS (MALDI +): m / z 1759.79 (M + H ⁺ ) (calculated: 1759.86).

(Synthesis example 28)
A peptide containing the amino acid sequence of SEQ ID NO: 33: Synthesis of V41Phg Phg-NDNTLFKW-Thi-IFNG-NH ₂ (V41Phg)
Phg: 2-phenylglycine Thi: 3-thienylalanine V41Phg was synthesized and purified by the same method as in Synthesis Example 1 using Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) 54 mg (0.020 mmol). (8.1 mg, yield 21.7%).
LRMS (MALDI +): m / z 1754.04 (M + H ⁺ ) (calculated: 1753.82).

(Synthesis example 29)
A peptide containing the amino acid sequence of SEQ ID NO: 34: Synthesis of N42Q VQDNTLFKW-Thi-IFNG-NH ₂ (N42Q)
Thi: 3-thienylalanine N42Q was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (11.7 mg, Yield 31.7%).
LRMS (MALDI +): m / z 1734.02 (M + H ⁺ ) (calculated: 173.85).

(Synthesis example 30)
Peptide comprising the amino acid sequence of SEQ ID NO: 35: Synthesis of _{N42D VDDNTLFKW-Thi-IFNG-NH} 2 (N42D)
Thi: 3-thienylalanine N42D was synthesized and purified by the same method as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (10.6 mg, Yield 28.9%).
LRMS (MALDI +): m / z 1721.57 (M + H ⁺ ) (calculated: 1720.82).

(Synthesis example 31)
A peptide containing the amino acid sequence of SEQ ID NO: 36: Synthesis of D43E VNENTLFKW-Thi-IFNG-NH ₂ (D43E)
Thi: 3-thienylalanine D43E was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (18.0 mg, Yield 48.8%).
LRMS (MALDI +): m / z 1734.33 (M + H ⁺ ) (calculated: 1734.83).

(Synthesis Example 32)
A peptide containing the amino acid sequence of SEQ ID NO: 37: Synthesis of N44E VNDETLFKW-Thi-IFNG-NH ₂ (N44E)
Thi: 3-thienylalanine N44E was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (7.7 mg, Yield 20.8%).
LRMS (MALDI +): m / z 1735.16 (M + H ⁺ ) (calculated: 1734.83).

(Synthesis example 33)
A peptide containing the amino acid sequence of SEQ ID NO: 38: Synthesis of N44D VNDDTLFKW-Thi-IFNG-NH ₂ (N44D)
Thi: 3-thienylalanine N44D was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (20.5 mg, Yield 55.9%).
LRMS (MALDI +): m / z 172.30 (M + H ⁺ ) (calculated: 1720.82).

(Synthesis Example 34)
A peptide containing the amino acid sequence of SEQ ID NO: 39: Synthesis of K48Dab VNDNTLF-Dbu-W-Thi-IFNG-NH ₂ (K48Dab)
Dbu: 2,4-diaminobutanoic acid Thi: 3-thienylalanine K48Dab was prepared in the same manner as in Synthesis Example 1 using Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) 54 mg (0.020 mmol). Synthesized and purified (13.9 mg, yield 38.5%).
LRMS (MALDI +): m / z 1691.36 (M + H ⁺ ) (calculated: 1691.80).

(Synthesis example 35)
Peptide comprising the amino acid sequence of SEQ ID NO: 40: Synthesis of _{I51Nva VNDNTLFKW-Thi-Nva-FNG} -NH 2 (I51Nva)
Thi: 3-thienylalanine Nva: norvaline I51Nva was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (23 0.1 mg, yield 63.5%).
LRMS (MALDI +): m / z 1705.45 (M + H ⁺ ) (calculated: 1705.82).

(Synthesis example 36)
A peptide containing the amino acid sequence of SEQ ID NO: 41: Synthesis of I51V VNDNTLFKW-Thi-VFNG-NH ₂ (I51V)
Thi: 3-thienylalanine I51V was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (22.2 mg, Yield 61.1%).
LRMS (MALDI +): m / z 1706.28 (M + H ⁺ ) (calculated: 1705.82).

(Synthesis example 37)
A peptide containing the amino acid sequence of SEQ ID NO: 42: Synthesis of I51Chg VNDNTLFKW-Thi-Chg-FNG-NH ₂ (I51Chg)
Thi: 3-thienylalanine Chg: 2-cyclohexylglycine I51Chg was synthesized and purified by the same method as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.). (20.3 mg, yield 54.6%).
LRMS (MALDI +): m / z 1746.59 (M + H ⁺ ) (calculated: 1745.85).

(Synthesis example 38)
Peptide comprising the amino acid sequence of SEQ ID NO: 43: Synthesis of _{I51Phg VNDNTLFKW-Thi-Phg-FNG} -NH 2 (I51Phg)
Thi: 3-thienylalanine Phg: 2-phenylglycine I51Phg was synthesized and purified in the same manner as in Synthesis Example 1 using Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) 54 mg (0.020 mmol). (8.4 mg, yield 22.7%).
LRMS (MALDI +): m / z 1739.70 (M + H ⁺ ) (calculated: 1739.80).

(Synthesis example 39)
A peptide containing the amino acid sequence of SEQ ID NO: 44: Synthesis of N53E VNDNTLFKW-Thi-IFEG-NH ₂ (N53E)
Thi: 3-thienylalanine N53E was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (10.0 mg, Yield 27.1%).
LRMS (MALDI +): m / z 1735.44 (M + H ⁺ ) (calculated: 1734.83).

(Synthesis example 40)
A peptide containing the amino acid sequence of SEQ ID NO: 45: Synthesis of N53Q VNDNTLFKW-Thi-IFQG-NH ₂ (N53Q)
Thi: 3-thienylalanine N53Q was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (20.0 mg, Yield 54.2%).
LRMS (MALDI +): m / z 1733.89 (M + H ⁺ ) (calculated: 173.85).

(Synthesis Example 41)
A peptide containing the amino acid sequence of SEQ ID NO: 46: Synthesis of N53D VNDNTLFKW-Thi-IFDG-NH ₂ (N53D)
Thi: 3-thienylalanine N53D was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (13.1 mg, Yield 35.7%).
LRMS (MALDI +): m / z 1712.13 (M + H ⁺ ) (calculated: 1720.82).

(Synthesis Example 42)
A peptide containing the amino acid sequence of SEQ ID NO: 47: Synthesis of G54βAla VNDNTLFKW-Thi-IFN-bAla-NH ₂ (G54βAla)
Thi: 3-thienylalanine bAla: β-alanine G54βAla was synthesized and purified by the same method as in Synthesis Example 1 using Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) 54 mg (0.020 mmol). (1.9 mg, 5.1% yield).
LRMS (MALDI +): m / z 1734.22 (M + H ⁺ ) (calculated: 173.85).

(Synthesis Example 43)
A peptide containing the amino acid sequence of SEQ ID NO: 48: Synthesis of G54Abu (4) VNDNTLFKW-Thi-IFN-4Abu-NH ₂ (G54Abu (4))
Thi: 3-thienylalanine 4Abu: 4-aminobutyric acid G54Abu (4) was prepared by the same method as in Synthesis Example 1 using Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) 54 mg (0.020 mmol). Synthesized and purified (4.7 mg, yield 12.7%).
LRMS (MALDI +): m / z 1747.96 (M + H ⁺ ) (calculated: 174.66).

(Synthesis Example 44)
A peptide containing the amino acid sequence of SEQ ID NO: 49: Synthesis of DF-97 Phg-NDNTLFKW-Hph-IFNG-NH ₂ (DF-97)
Phg: 2-phenylglycine Hph: homophenylalanine DF-97 was synthesized and purified by the same method as in Synthesis Example 1 using Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) 54 mg (0.020 mmol). (18.0 mg, yield 48.0%).
LRMS (MALDI +): m / z 1761.08 (M + H ⁺ ) (calculated: 1761.88).

(Synthesis Example 45)
Peptide containing the amino acid sequence of SEQ ID NO: 50: Synthesis of DF-98 Phg-NDNTLFKF-Hph-IFNG-NH ₂ (DF-98)
Phg: 2-phenylglycine Hph: homophenylalanine DF-98 was synthesized and purified by the same method as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.). (18.0 mg, yield 48.0%).
LRMS (MALDI +): m / z 1722.27 (M + H ⁺ ) (calculated: 172.86).

(Synthesis example 46)
A peptide containing the amino acid sequence of SEQ ID NO: 51: Synthesis of DF-99 Phg-NDNTLFKW-Hph-I-Phe (4-F) -NG-NH ₂ (DF-99)
Phg: 2-phenylglycine Hph: homophenylalanine Phe (4-F): 4-fluorophenylalanine DF-99 is Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) 54 mg (0.020 mmol). It was synthesized and purified by the same method as in Synthesis Example 1 (18.0 mg, yield 48.0%).
LRMS (MALDI +): m / z 1780.36 (M + H ⁺ ) (calculated: 1779.87).

(Synthesis example 47)
A peptide containing the amino acid sequence of SEQ ID NO: 52: Synthesis of DF-100 Phg-NDNTLFKF-Hph-I-Phe (4-F) -NG-NH ₂ (DF-100)
Phg: 2-phenylglycine Hph: homophenylalanine Phe (4-F): 4-fluorophenylalanine DF-100 is Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) 54 mg (0.020 mmol). It was synthesized and purified by the same method as in Synthesis Example 1 (18.0 mg, yield 48.0%).
HRMS (ES +): m / z 1740.8547 (M + H ⁺ ) (calculated: 1740.8550).

(Synthesis example 48)
Peptide comprising the amino acid sequence of SEQ ID NO 53: DF-111 synthetic Phg-NDNTLFK-Phe (4- F) -Hph-I-Phe (4-F) -NG-NH 2 (DF-111)
Phg: 2-phenylglycine Phe (4-F): 4-fluorophenylalanine Hph: homophenylalanine DF-111 is Rink Amide resin (0.37 mmol / g, Watanabe Chemical Co., Ltd.) 54 mg (0.020 mmol). It was synthesized and purified by the same method as in Synthesis Example 1 (16.1 mg, yield 43.0%).
HRMS (ES +): m / z 1758.8428 (M + H ⁺ ) (calculated: 1758.8456).

(Synthesis example 49)
A peptide containing the amino acid sequence of SEQ ID NO: 54: Synthesis of DF-115 Phg-NDNTLFKF-Hph-I-Phe (4-OMe) -NG-NH ₂ (DF-115)
Phg: 2-phenylglycine Hph: homophenylalanine Phe (4-OMe): 4-methoxyphenylalanine DF-115 is Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) 54 mg (0.020 mmol). It was synthesized and purified by the same method as in Synthesis Example 1 (11.8 mg, yield 31.5%).
HRMS (ES +): m / z 1752.8719 (M + H ⁺ ) (calculated: 1752.8750).

(Synthesis example 50)
Peptide containing the amino acid sequence of SEQ ID NO: 55: Synthesis of HFs38-54 (comparative example)
EEDVNDNTLFKWMIFNG-NH ₂ (HFs38-54)
HFs38-54 was synthesized and purified in the same manner as in Synthesis Example 1 using 54 mg (0.020 mmol) of Rink Amide resin (0.37 mmol / g, Watanabe Chemical Industry Co., Ltd.) (8.1 mg, yield 18. 4%).
HRMS (ES +): m / z 2070.9595 (M + H ⁺ ) (calculated: 2070.9595).

(Test Example 1) Evaluation of myostatin inhibitory activity of HFs41-54, HFs42-53 and HFs38-54 by in vitro reporter assay Evaluation of myostatin inhibitory activity of HFs41-54, HFs42-53 and HFs38-54 was performed by the following reporter assay. Carried out. The result is shown in FIG. Compared with HFs38-54, HFs41-54 and HFs42-53 showed a remarkable myostatin inhibitory activity of 80% or more (luciferase activity 20% or less) at a concentration of 10 μM.

  In the figure, "myostatin-free" shows the results for the test group to which dimethyl sulfoxide (DMSO) containing no myostatin was added. “Myostatin only” shows the results for the test plots containing 8 ng / mL myostatin and no test sample. In addition, the result of the reporter assay was calculated as a result of the test section containing 8 ng / mL of myostatin and not containing the test sample as myostatin activity 100% (relative luciferase activity 100%), and 3 wells for each test section were calculated. It is shown as a mean value ± standard deviation.

(1) Cell Culture Human fetal kidney cells HEK293 cells are 10% (v / v) fetal bovine serum (FBS) supplemented with 1% (v / v) non-essential amino acid (Fujifilm Wako Pure Chemical Industries, Ltd.). ) -Containing DMEM (Nacalai Tesque, Inc.) medium was used to culture at 37 ° C. in a 5% (v / v) CO ₂ incubator.

(2) In vitro reporter assay HEK293 cells were seeded on a D-Lys-corted 96-well transparent plate (Thermo Fisher Scientific Co., Ltd.) at 2.0 × 10 ⁴ cells (100 μL DMEM + 10% (v / v) FBS) per well, It was cultured for 24 hours.

  On the following day, 100 ng of pGL4.48 [luc2P / SBE / Hygro] (Promega) per well and 10 ng of pGL4 [hRluc / TK] (Promega) as an internal control were added to the final concentration of FuGENE HD (Promega). Of 41.25 μg / mL was mixed using OPTI-MEM and added to the medium in the wells. After culturing the cells at 37 ° C. for 24 hours, the cell culture medium was replaced with serum-free DMEM and the cells were cultured for 8 hours.

  The peptide as a test sample was suspended in DMSO at a stock solution of 10 mM and stored at -30 ° C. One hour before adding to the medium, the cells were suspended in serum-free DMEM and allowed to stand at room temperature (25 ° C) for 20 minutes. Then, the peptide was added to the medium at a final concentration of 10 μM and myostatin (Merck Millipore) at 8 ng / mL, and then cultured for 4 hours.

  The prodomain protein (RSD) used as a positive control was suspended in PBS containing 0.1% (v / v) BSA so as to be 10 μM as a stock solution, and stored at −30 ° C. One hour before adding to the medium, the cells were suspended in serum-free DMEM and allowed to stand at room temperature (25 ° C) for 20 minutes. Then, 10 nM final concentration of prodomain protein and 8 ng / mL of myostatin (Merck Millipore) were added to the medium, and then cultured for 4 hours.

  After culturing for 4 hours, the culture solution was removed with an aspirator, and the cells were washed with 1 × PBS. Then, 50 μL of Passive Lysis buffer (Promega) was added per well to lyse the cells. The lysate was centrifuged at 4500 rpm for 6 minutes at 4 ° C. After transferring 20 μL of the supernatant after centrifugation to a white 96-well plate (Costar), 50 μL of Luciferase Assay Reagent (Promega) was added, and luminescence was detected by Luminoskan Ascent (Thermo Fisher Scientific). Firefly luciferase activity was measured. Furthermore, after adding 50 μL of Stop & Glo Buffer, luminescence was detected by Luminoskan Ascent to measure Renilla luciferase activity, which was used as an internal control.

Test Example 2 Evaluation of Activin Inhibitory Activity and TGF-β1 Inhibitory Activity of HFs41-54 and Myostatin Prodomain-Derived Peptides by In Vitro Reporter Assay The activin inhibitory activity of HFs41-54 was 8 ng / mL instead of 8 ng / mL. / ML activin was used and evaluated according to the test method of Test Example 1. Further, the TGF-β1 inhibitory activity was evaluated according to the test method of Test Example 1 using 2.5 ng / mL TGF-β1 in place of 8 ng / mL myostatin.

  As a control, the activin inhibitory activity and TGF-β1 inhibitory activity of peptides derived from myostatin prodomain were evaluated.

Peptide derived from myostatin prodomain (peptide 7) is a 23-residue inhibitory peptide identified in the mouse myostatin precursor prodomain and is disclosed in the following references:
Takayama, K .; Noguchi, Y .; Aoki, S .; Takayama, S .; Et al. Identification of the minimum peptide from mouse myostatin, product for for human myostatin inhibition. J. Med. Chem. 2015, 58, 1544-1549.

  The activin inhibitory activity of peptide 7 was evaluated according to the test method of Test Example 1 using 8 ng / mL activin instead of 8 ng / mL myostatin. Further, the TGF-β1 inhibitory activity was evaluated according to the test method of Test Example 1 using 2.5 ng / mL TGF-β1 in place of 8 ng / mL myostatin.

  The result is shown in FIG. It can be seen that HFs41-54 hardly inhibited activin and TGF-β1 at a concentration of 10 μM as compared to peptide 7.

(Test Example 3) Effect of HFs41-54 on tibialis anterior muscle of mouse (in vivo evaluation)
In order to verify the muscle mass increasing effect of HFs41-54 in vivo, evaluation was performed by the following method.

  HFs41-54 was dissolved in physiological saline containing 1% (v / v) DMSO so as to have a concentration of 0.5 mM. 20 nmol of HFs41-54 (40 μL) was intramuscularly administered to one tibialis anterior muscle (n = 4) of 10-week-old C57BL6J mice (purchased from Japan SLC, Inc.) under anesthesia. As a control group (Cont), albumin was dissolved in physiological saline containing 1% (v / v) DMSO at 0.5 mM. 20 nmol of albumin (40 μL) was intramuscularly administered to the tibialis anterior muscle of the leg opposite to the side to which HFs41-54 was administered.

  Four weeks later, the mice were sacrificed and muscles were autopsied. The result is shown in FIG. Based on its myostatin inhibitory activity, HFs41-54 increased the muscle mass of tibialis anterior muscle of mice by about 10% compared with the control group.

(Test Example 4) Evaluation of Myostatin Inhibitory Activity of G54A by In Vitro Reporter Assay The myostatin inhibitory activity of G54A was evaluated according to the test example of Test Example 1. FIG. 4 shows the results. G54A exhibited a remarkable myostatin inhibitory activity of 80% or more (luciferase activity 20% or less) at a concentration of 10 μM.

(Test Example 5) Evaluation of Myostatin Inhibitory Activity of M50Nle and M50Thi by In Vitro Reporter Assay The myostatin inhibitory activity of M50Nle and M50Thi was evaluated according to the test example of Test Example 1. The result is shown in FIG. M50Nle showed an excellent myostatin inhibitory activity of 70% or more (luciferase activity 30% or less) at a concentration of 10 μM. In addition, M50Thi showed a remarkable myostatin inhibitory activity of 80% or more (luciferase activity 20% or less) at a concentration of 10 μM.

(Test Example 6) Evaluation of Myostatin Inhibitory Activity of M50Thi Derivatives by In Vitro Reporter Assay For the peptides synthesized in Synthesis Examples 6 to 43, the myostatin inhibitory activity was 3 μM at a concentration of each peptide according to the test method of Test Example 1. Was evaluated. The results are shown in FIGS. 6 and 7. All peptides showed the same or stronger myostatin inhibitory activity as M50Thi at a concentration of 3 μM.

  Among them, W49 (2-Nal), W49F, W49Chg, M50Phg, M50Hph, F52Thi, F52Phe (4-F), F52Phg, F52Chg, V41Nva, V41I, V41L, V41Chg, V41Phg, I51V, I51Chg, N53Q, N53D, G54βAla and G54Abu (4) showed a particularly remarkable myostatin inhibitory activity of 40% or more (luciferase activity 60% or less) at a concentration of 3 μM.

(Test Example 7) Evaluation of Myostatin Inhibitory Activity of V41Phg Derivative by In Vitro Reporter Assay For the peptides synthesized in Synthesis Examples 44 to 47, according to the test method of Test Example 1, the concentration of each peptide was 3 μM at a myostatin inhibitory activity. Was evaluated. FIG. 8 shows the result. All peptides showed myostatin inhibitory activity at a concentration of 3 μM, similar to V41Phg.

  Among them, DF-97, DF-99 and DF-100 exhibited a particularly remarkable myostatin inhibitory activity of 40% or more (luciferase activity 60% or less) at a concentration of 3 μM.

(Test Example 8) Evaluation of Myostatin Inhibitory Activity of DF-100 Derivative by In Vitro Reporter Assay For the peptides synthesized in Synthesis Examples 48 to 49, the concentration of each peptide was 3 μM at a concentration of 3 μM according to the test method of Test Example 1. The inhibitory activity was evaluated. The result is shown in FIG. All peptides showed remarkable myostatin inhibitory activity at a concentration of 3 μM, similar to DF-100.

(Test Example 9) Concentration-dependent evaluation of myostatin inhibitory activity of DF-100 by in vitro reporter assay According to the test method of Test Example 1, DF-100 was concentration-dependent (20 μM to 0.31 μM) of myostatin. The inhibitory activity was evaluated. The result is shown in FIG. DF-100 showed a concentration-dependent myostatin inhibitory activity. The IC ₅₀ value (50% inhibitory concentration) of DF-100 was 3.92 μM.

Claims (14)

A peptide comprising the amino acid sequence represented by the following formula (1) and having 16 or less amino acid residues, or a pharmaceutically acceptable salt thereof, or a prodrug thereof:
In the above formula (1),
X ¹ is an amino acid residue or a defect selected from the group consisting of Val, Leu, Ile, norvaline, 2-aminobutyric acid, 2-cyclohexylglycine, 2-phenylglycine, norleucine and isovaline;
X ² is an amino acid residue selected from the group consisting of Asn, Gln, Asp and Glu;
X ³ is Glu or Asp;
X ⁴ is an amino acid residue selected from the group consisting of Asn, Asp, Glu and Gln;
X ⁵ is an amino acid residue selected from the group consisting of Ser, Thr, 2-hydroxyglycine and homoserine;
X ⁶ is Leu or 2-phenylglycine;
X ⁷ is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine, homophenylalanine, 2-cyclohexylglycine, Trp and Tyr;
X ⁸ is an amino acid residue selected from the group consisting of Lys, 2,4-diaminobutanoic acid, Arg, His, 2,3-diaminopropionic acid and ornithine;
X ⁹ is an amino acid residue selected from the group consisting of Phe, Trp, 3-naphthylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and homophenylalanine;
X ¹⁰ is selected from the group consisting of Met, Phe, norleucine, 3-thienylalanine, 2-phenylglycine, homophenylalanine, homomethionine, Val, Leu, Ile, 2-aminobutyric acid, norvaline, isovaline and 2-cyclohexylglycine. Is an amino acid residue that is
X ¹¹ is an amino acid residue selected from the group consisting of Ile, Val, norvaline, 2-cyclohexylglycine, 2-phenylglycine, Leu, 2-aminobutyric acid, norleucine and isovaline;
X ¹² is an amino acid residue selected from the group consisting of Phe, homophenylalanine, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine, 4-methoxyphenylalanine and 4-chlorophenylalanine. ;
X ¹³ is an amino acid residue selected from the group consisting of Asn, Gln, Asp and Glu; and X ¹⁴ consists of Gly, Ala, β-alanine, 4-aminobutyric acid, 2-aminoisobutyric acid and Pro. An amino acid residue or deletion selected from the group. X ⁷ is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine, homophenylalanine and 2-cyclohexylglycine;
X ¹⁰ is an amino acid residue selected from the group consisting of Met, Phe, norleucine, 3-thienylalanine, 2-phenylglycine, homophenylalanine, homomethionine, Val, Leu, Ile, 2-aminobutyric acid, norvaline and isovaline. And
X ¹² is an amino acid residue selected from the group consisting of Phe, homophenylalanine, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine, 4-fluorophenylalanine and 4-methoxyphenylalanine; and X ¹⁴ is , Gly, Ala, β-alanine, 4-aminobutyric acid and 2-aminoisobutyric acid, or a deficient amino acid residue thereof, or a pharmaceutically acceptable salt thereof. , Or their prodrugs. X ¹ is an amino acid residue selected from the group consisting of Val, Leu, Ile, norvaline, 2-aminobutyric acid, 2-cyclohexylglycine, 2-phenylglycine, norleucine and isovaline;
X ¹⁰ is an amino acid residue selected from the group consisting of Met, Phe, 3-thienylalanine, 2-phenylglycine, homophenylalanine and homomethionine; and X ¹⁴ is Gly, Ala, β-alanine, 4 -The peptide according to claim 2, which is an amino acid residue selected from the group consisting of aminobutyric acid and 2-aminoisobutyric acid, or a pharmaceutically acceptable salt thereof, or a prodrug thereof. X ² is Asn or Glu;
X ³ is Asp;
X ⁴ is an amino acid residue selected from the group consisting of Asn, Glu and Gln;
X ⁵ is Thr;
X ⁶ is Leu;
X ⁷ is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine and 2-cyclohexylglycine;
X ¹⁰ is an amino acid residue selected from the group consisting of Phe, 3-thienylalanine, 2-phenylglycine and homophenylalanine;
X ¹¹ is an amino acid residue selected from the group consisting of Ile, Val and 2-cyclohexylglycine;
X ¹³ is an amino acid residue selected from the group consisting of Asn, Gln and Asp; and X ¹⁴ is an amino acid residue selected from the group consisting of Gly, β-alanine and 4-aminobutyric acid. The peptide according to claim 3, or a pharmaceutically acceptable salt thereof, or a prodrug thereof. X ⁴ is Asn or Gln;
X ⁷ is Phe;
X ⁸ is Lys;
X ⁹ is an amino acid residue selected from the group consisting of Phe, Trp, 3- (2-naphthyl) alanine, 2-cyclohexylglycine, 4-fluorophenylalanine and homophenylalanine;
X ¹⁰ is an amino acid residue selected from the group consisting of 3-thienylalanine, 2-phenylglycine and homophenylalanine; and X ¹² is Phe, 2-phenylglycine, 3-thienylalanine, 2-cyclohexylglycine. The peptide according to claim 4, which is an amino acid residue selected from the group consisting of and 4-fluorophenylalanine, or a pharmaceutically acceptable salt thereof, or a prodrug thereof.   The peptide according to any one of claims 1 to 5, or a pharmaceutically acceptable peptide thereof, wherein the peptide represented by the formula (1) contains any one of the amino acid sequences represented by SEQ ID NOs: 6 to 54. Salts, or their prodrugs.   The peptide according to claim 6, wherein the peptide represented by the formula (1) contains any one of the amino acid sequences represented by SEQ ID NOs: 6, 8 and 10 to 15, or a pharmaceutically acceptable salt thereof. , Or their prodrugs.   The peptide represented by the formula (1) contains any one of the amino acid sequences represented by SEQ ID NOs: 13, 15 to 33, 37, 39, 41, 42 and 45 to 54. The described peptide or a pharmaceutically acceptable salt thereof, or a prodrug thereof.   The peptide represented by the formula (1) has any one of the amino acid sequences represented by SEQ ID NOs: 17 to 19, 21 to 25, 27, 29 to 33, 41, 42, 45 to 49 and 51 to 53. The peptide according to any one of claims 6 to 8 or a pharmaceutically acceptable salt thereof, or a prodrug thereof.   A myostatin inhibitor comprising the peptide according to any one of claims 1 to 9 or a pharmaceutically acceptable salt thereof, or a prodrug thereof.   A preventive and / or therapeutic agent for muscular atrophy disorder, which comprises the peptide according to any one of claims 1 to 9, a pharmaceutically acceptable salt thereof, or a prodrug thereof.   The preventive and / or therapeutic agent for muscular atrophy disorder according to claim 11, wherein the muscular atrophy disorder is muscular dystrophy.   Prevention and / or treatment of muscular atrophy disorder, which comprises administering to a patient an effective amount of the peptide according to any one of claims 1 to 9 or a pharmaceutically acceptable salt thereof, or a prodrug thereof. Method.   The method for preventing and / or treating muscular atrophy disorder according to claim 13, wherein the muscular atrophy disorder is muscular dystrophy.