Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K45/00—Medicinal preparations containing active ingredients not provided for in groups A61K31/00 - A61K41/00
  • A61K45/06—Mixtures of active ingredients without chemical characterisation, e.g. antiphlogistics and cardiaca
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/335—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/70—Carbohydrates; Sugars; Derivatives thereof
  • A61K31/7042—Compounds having saccharide radicals and heterocyclic rings
  • A61K31/7052—Compounds having saccharide radicals and heterocyclic rings having nitrogen as a ring hetero atom, e.g. nucleosides, nucleotides
  • A61K31/706—Compounds having saccharide radicals and heterocyclic rings having nitrogen as a ring hetero atom, e.g. nucleosides, nucleotides containing six-membered rings with nitrogen as a ring hetero atom
  • A61K31/7064—Compounds having saccharide radicals and heterocyclic rings having nitrogen as a ring hetero atom, e.g. nucleosides, nucleotides containing six-membered rings with nitrogen as a ring hetero atom containing condensed or non-condensed pyrimidines
  • A61K31/7076—Compounds having saccharide radicals and heterocyclic rings having nitrogen as a ring hetero atom, e.g. nucleosides, nucleotides containing six-membered rings with nitrogen as a ring hetero atom containing condensed or non-condensed pyrimidines containing purines, e.g. adenosine, adenylic acid
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
  • A61P9/04—Inotropic agents, i.e. stimulants of cardiac contraction; Drugs for heart failure
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
  • A61P9/06—Antiarrhythmics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
  • A61P9/08—Vasodilators for multiple indications

Definitions

• the present invention relates to methods and compositions for treating Human Cardiac Hypertrophy (HCM). More specifically, the present invention relates to the use of an antagonist of Epac for treating HCM.
• HCM Human Cardiac Hypertrophy
• Physiologic hypertrophy such as an exercise-induced cardiac hypertrophy
• pathologic hypertrophy such as pressure oyerload-induced hypertrophy
• pathologic stimuli that, if not ameliorated, usually leads to heart failure.
• HCM Human cardiac hypertrophy
• Cardiac hypertrophy is a potent risk factor for the development of cardiac arrhythmias, diastolic dysfunction, congestive heart failure, and death. (Hennersdorf et al. 2001; Vakili et al. 2001) " .
• beta-blocking drugs slow the heart beat and reduce its force of contraction. These drugs usually relieve chest pain, breathlessness and palpitation, but occasionally excessive heart rate slowing with these drugs can cause fatigue.
• the second major group of drugs used are the calcium antagonists or calcium channel blockers.
• verapamil is the drug which has been most commonly used in HCM. It improves the filling of the heart and like beta-blockers, reduces symptoms such as chest pain, breathlessness and palpitations. Also, like beta-blockers, verapamil can cause excessive slowing of the heart rate and lower blood pressure.
• Anti-arrhythmic drugs have been also used for treating of cardiac hypertrophy. These drugs might be used when an arrhythmia such as tachycardia is detected and felt to be important in an individual case.
• Amiodarone Cordarone
• Ca2+-sensitive signaling pathways play crucial roles in cardiomyocyte hypertrophy (Frey et al, 2000).
• Two prominent Ca2+-dependent pathways involve the Ser/Thr protein phosphatase calcineurin (Liang et al, 2003; Molkentin, 2004) and Ca2+/calmodulin-dependent protein kinase II (CaMKII) (Zhang & Brown, 2004).
• Activation ' of calcineurin by Ca2+ results in the dephosphorylation and nuclear translocation of cytoplasmic nuclear factor of activated T cells (NFAT) transcription factors which then upregulate transcription of hypertrophic genes.
• NFAT cytoplasmic nuclear factor of activated T cells
• Calcineurin can also relieve the inhibition of class II histone deacetylases (HDACs) on the myocyte enhancer factor 2 (MEF2), thereby allowing this transcription factor to induce hypertrophic gene expression.
• HDACs histone deacetylases
• MEF2 myocyte enhancer factor 2
• CaMKII is known to activate MEF2 upon HDACs phosphorylation (McKinsey & Olson, 2004). To date, the participation of small G proteins of the Rlio family in the regulation of these hypertophic signaling cascades is not well defined.
• Rho is important for the formation of stress fibers and focal adhesions in fibroblasts
• Rac and Cdc42 are involved in the regulation of more dynamic structures such as membrane ruffles, lamellipodia and filopodia (Hall, 1998).
• Rho proteins have pointed out the role of Rho proteins in the development of cardiomyocyte hypertrophy (Clerk & Sugden, 2000)..
• Rho proteins especially Rac control hypertrophic response and are likely to be involved in cardiac remodelling, and the pathogenesis of cardiomyopathy characterized by cellular enlargement.
• Cyclic adenosine 3 ',5 '-monophosphate is one of the most important second messenger in the heart because it regulates many physiological processes such as cardiac contractility, relaxation and automaticity.
• these effects are attributed to activation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and protein kinase A (PKA) by c AMP' (Fimia & Sassone-Corsi, 2001).
• HCN hyperpolarization-activated cyclic nucleotide-gated
• PKA protein kinase A
• a classical example is the stimulation of cardiac ⁇ -adrenergic receptors in which PKA phosphorylates several key proteins involved in excitation-contraction coupling, such as L- type Ca 2+ channels, phospholamban, ryanodine receptors (RyR) and troponin I (Bers & Ziolo, 2001).
• PKA phosphorylates several key proteins involved in excitation-contraction coupling, such as L- type Ca 2+ channels, phospholamban, ryanodine receptors (RyR) and troponin I (Bers & Ziolo, 2001).
• Epac exchange proteins directly activated by cAMP
• PKA guanine nucleotide exchange factors
• Epac 1 and Epac 2 both consisting of a regulatory and a catalytic region (de Rooij et al, 1998; Kawasaki et al, 1998). Epacl is highly expressed in the heart (Kawasaki et al, 1998). Epac 2 has an additional cAMP binding domain which is dispensable for cAMP- induced Rap activation (de Rooij et al, 2000).
• Epac catalyses the exchange of GDP for a GTP of the small GTPases Rap, allowing interaction with their target effectors (Rehmann et al, 2003).
• Epac is involved in cell adhesion (Enserink et al, 2004; Rangarajan et al, 2003), neurite extension (Christensen et al, 2003), and regulates the amyloid precursor protein and insulin secretion (Maillet et al, 2003; Ozaki et al,
• a first aspect of this invention thus resides in the use of an antagonist of Epac for the manufacture of a medicament for treating cardiac hypertrophy, and especially, human cardiac hypertrophy.
• a further object of this invention resides in a method for treating cardiac hypertrophy, especially human cardiac hypertrophy, comprising administering at least one antagonist of Epac to the subject.
• a further object of the invention resides in a pharmaceutical composition useful for treating cardiac hypertrophy, and especially human cardiac hypertrophy, comprising at least one antagonist of Epac.
• the antagonist of Epac is a compound natural or not that impedes or limits the activation of Epac by cAMP or hypertrophic stimuli such as angiotensin II, endothelin I and phenylephrine, hi a particular embodiment, said antagonist is a cAMP analog, that competes with cAMP for binding to Epac, but to thereupon either block or significantly inhibit the biological response induced by cAMP or hypertrophic stimuli such as angiotensin II, endothelin I and phenylephrine.
• cAMP analog candidates are those compounds that have " an affinity for ' binding to Epac that is either -not significantly different from, or higher than cAMP, and that induce no, or a significantly lower level of biological response than native cAMP.
• the antagonist of Epac is a compound that is able to inhibit the expression of Epac.
• said antagonist is an antisense oligonucleotide, a siRNA or a ribozyme.
• a further object of the invention resides in a method for screening a compound, and especially a cAMP analog, that affects the activation of Epac.
• the screening method involves the steps of: - a) incubating Epac with i) at least one effector of Epac, chosen among, but not limited to, Rapl, Rap2, Rac or Ras, ii) cAMP and iii) said compound to be tested,
• the activation of Rapl is assessed by detecting in real time the release of mGDP with a fluorescence spectrometer as previously described (Van den Berghe et al, 1997).
• the screening method involves the step of : a) providing cardiomyocytes that either constitutively expressed an activated form of Epac or Epac wild type, or have been treated with hypertrophic stimuli such as angiotensin II, endothelin I and phenylephrine. b) exposing said cardiomyocyte to one of the compounds to be tested
• cardiomyocyte hypertrophy properties are determined by measuring cell size, protein content and/or the expression of mRNA coding for hypertrophic gene markers such as the natriuretic factor or NFAT transcriptional activity.
• the screening method can result in the combination of the two above described methods.
• a further object of the invention resides in-a-non -human model of cardiac hypertrophy wherein cardiac hypertrophy has been induced by the specific expression- of a positive ⁇ dominant form of Epac, and especially Epacl.
• said model is a mouse
• said positive dominant form of Epac is under the control of a cardiac specific promoter such as ⁇ -Myosin Heavy Chain promoter.
• the positive dominant form of Epacl result in Epac- ⁇ cAMP which contains a deletion of the first 322 amino acids of Epacl (de Rooij et al., 1998).
• Epac is the protein shown in SEQ ID NO: 2 (Epacl, Accession: NM_006105) or SEQ ID NO: 4 (Epac2, Accession: NM_007023), or a partial protein thereof, or an ester, amide or salt thereof.
• the present invention relates to the use of at least one Epac (Exchange Protein directly
• Activated by cAMP) antagonist for the manufacture of a medicament intended for the prevention or the treatment of pathologies selected from the list comprising cardiac hypertrophy, cardiac arrhythmias, valvulopathies, diastolic dysfunction, chronic heart failure, ischemic heart failure, and myocarditis.
• An antagonist of Epac is herein defined as a compound that is able to inhibit the expression, the activation or the activity of Epac.
• An antagonist of Epac that inhibits the expression of Epac means that said antagonist impedes the process of transcription of the Epac gene and / or of the translation of the mRNA of Epac into the Epac protein.
• An antagonist of Epac that inhibits the activation of Epac means that said antagonist impedes the activators of Epac to activate Epac.
• An antagonist of Epac that inhibits the activity of Epac means that said antagonist impedes Epac function.
• Such an antagonist may block the catalysis by Epac of the exchange of GDP for a GTP.
• the invention relates in particular to the use as defined above, wherein the antagonist is selected from the list comprising Epac activation inhibitors, Epac activity inhibitors, Epac intracellular localization disruption agents, and Epac expression inhibitors.
• An "Epac expression inhibitor” impedes or decreases the expression of the protein
• Epac Epac.
• Said inhibitor may block or decrease the transcription and / or the translation process of Epac.
• the inhibition of Epac expression can be assessed by Western blot or reverse transcriptase polymerase chain reaction.
• Epac activation inhibitor impedes the activation of Epac, particularly by the activators of Epac such as cAMP.
• the inhibition of Epac activation can be assessed by measuring the GTP form of its effector, Rapl or Rap2, using pull down assay as described in Maillet et al., 2003.
• An "Epac activity inhibitor” is a compound which impedes the normal function of Epac, such as the exchange of GDP for a GTP or the activation of the c-Jun NH2-terminal kinase.
• Epac activity can be assessed by measuring either the GTP form of its effector, Rapl or Rap2 using pull down assay or the activation of c-Jun NH2-terminal kinase using a kinase assay as described in Hochbaum et al. (2003).
• Epac intracellular localization disruption agent is a compound which impedes the proper cellular localization of Epac. Epac cellular distribution can be assessed by immunocytochemistry using Epac selective antibodies.
• the invention further relates to the use as defined above, wherein the antagonist is an
• Epac activation inhibitor selected from the list comprising:
• - cAMP analogues such as cAMP derivatives or 8-(4-chlorophenylthio)-2' ⁇ O- methyladenosine-3 ' -5 -cyclic monophosphate (8-CPT-2'-O-Me-cAMP) derivatives, - Brefeldin A or derivatives thereof.
• Compounds capable of inhibiting the activation of Epac include in particular those able to interact with natural agonists of Epac, such as cAMP, and /or to interact in the binding of said agonists to Epac, and / or to inhibit the activation of Epac resulting from said binding.
• agonist of Epac refers to compounds that bind to Epac and activate Epac through this binding.
• An inhibitor of activation of Epac may be an antibody or fragment thereof, or an aptamer directed against the Epac cAMP binding sites, thus impeding the binding of said cAMP to Epac.
• antibody refers to a polyclonal or monoclonal antibody.
• polyclonal and monoclonal refer to the degree of homogeneity of an antibody preparation, and are not intended to be limited to a particular method of production.
• a mammal such as a rabbit, a mouse, or a hamster
• an immunogenic form of the protein such as the entire protein or a part of it.
• the protein or part of it can be administered in the presence of an adjuvant.
• immunogenic refers to the ability of a molecule to elicit an antibody response.
• Techniques for conferring immunogenicity to a protein or part of it which is not itself immunogenic include conjugation to earners or other techniques well known in the art.
• the immunization process can be monitored by detection of antibody titers in plasma or serum. Standard immunoassays, such as ELISA can be used with the immunogenic protein or peptide as antigen to assess the levels of antibody.
• an antibody which is an activation inhibitor of Epac is directed against Epac cAMP binding sites.
• aptamer refers to a nucleic acid molecule or oligonucleotide sequence that binds specifically to the Epac protein.
• Aptamers may be DNA or RNA and may include nucleotide derivatives. Aptamers may be a single strand or a double strand of usually 16 to 60 nucleotides long.
• SELEX Systematic Evolution of Ligands by Exponential Enrichment
• an aptamer which is an activation inhibitor of Epac binds specifically to Epac cAMP binding sites.
• oligonucleotide refers to a nucleic acid, generally of at least 10, preferably at least 12, more preferably at least 15, and still preferably at least 20 nucleotides, preferably no more than 100 nucleotides, still preferably no more than 70 nucleotides, and which is hybridizable to a Epac genomic DNA, cDNA, or mRNA.
• An inhibitor of activation of Epac can consist in an analog of cAMP which impedes the binding of said cAMP to Epac.
• said antagonist is a cAMP analog, that competes with cAMP for binding to Epac, but to thereupon either block or significantly inhibit the biological response induced by cAMP or hypertrophic stimuli such as angiotensin II, endothelin I and phenylephrine.
• cAMP analog candidates are those compounds that have an affinity , for binding to Epac that is either not significantly different from, or higher than cAMP, and that induce no, or a significantly lower level of biological response than native c AMP.
• Brefeldin A Another inhibitor of Epac activation may be Brefeldin A, a small hydrophobic compound produced by toxic fungi.
• Brefeldin A is a macrocyclic lactone exhibiting a large range of antibiotic activity. Brefeldin A can bind at the Rap-GDP/Epac interface, thus freezing the complex in an abortive conformation that cannot proceed to nucleotide dissociation.
• the invention also relates to the use as defined above, wherein the antagonist.
• GEF Guanine nucleotide Exchange Factor
• REM Ras Exchange Motif
• the Guanine nucleotide Exchange Factor domain (GEF) is located into the catalytic region of Epac protein and is involved in Epac catalytic activity.
• the GEF domain of Epac is located between amino acids 616-848 of Epacl and 768-1005 of Epac2.
• the Ras Exchange Motif (REM) domain is located into the catalytic region of Epac protein and participates to Epac catalytic activity.
• the REM domain of Epac is located between amino acids 342-466 of Epacl and 495-615 of Epac2.
• the invention also relates to the use as defined above, wherein the antagonist is an Epac intracellular localization disruption agent, selected from the list comprising:
• Epac cellular localization domain such as the Dishevelled EgI- 10 Pleckstrin (DEP) domain
• Epac cellular localization domain refers to a domain which is involved in membrane localization.
• An Epac cellular localization domain is for example the Dishevelled EgI- 10 Pleckstrin (DEP) domain.
• the invention also relates to the use as defined above, wherein the antagonist is an
• Epac expression inhibitor selected from the list comprising:
• RNA a double stranded RNA, a siRNA or a shRNA, comprising Epac nucleic acid sequences, - a ribozyme directed against Epac mRNAs.
• Inhibitors of the expression of Epac include for instance- antisense oligonucleotides, or interfering RNAsi, or ribozymes, targeting the Epac gene.
• gene means a DNA sequence that codes for or corresponds to a particular sequence of amino acids which comprise all or part of one or more proteins or enzymes, and may or may not include regulatory DNA sequences, such as promoter sequences, which determine for example the conditions under which the gene is expressed.
• a "promoter” or “promoter sequence” is a DNA regulatory region capable of binding RNA polymerase in a cell and initiating transcription of a downstream (3 1 direction) coding sequence. Some genes, which are not structural genes, may be transcribed from DNA to RNA, but are not translated into an amino acid sequence. Other genes may function as regulators of structural genes or as regulators of DNA transcription. In particular, the term gene may be intended for the genomic sequence encoding a protein, i.e.
• a "coding sequence” or a sequence “encoding” an expression product, such as a RNA, polypeptide, protein, or enzyme is a nucleotide sequence that, when expressed, results in the production of that RNA, polypeptide, protein, or enzyme, i.e., the nucleotide sequence encodes an amino acid sequence for that polypeptide, protein or enzyme.
• a coding sequence for a protein may include a start codon (usually ATG) and a stop codon.
• Epac gene denotes the gene encoding for Epac (exchange proteins directly activated by cAMP) of any species, especially human Epac, but also other mammals or vertebrates to which the invention can apply. Unless otherwise indicated, the term “Epac” is used indifferently to designate the Epac gene or the encoded protein Epac throughout the text. There are two isoforms of Epac, Epac 1 (also named Rap guanine nucleotide exchange factor (GEF) 3) and Epac 2 (also named Rap guanine nucleotide exchange factor (GEF) 4) such as described in de Rooij et al, 1998 and Kawasaki et al, 1998.
• Epac 1 also named Rap guanine nucleotide exchange factor (GEF) 3
• Epac 2 also named Rap guanine nucleotide exchange factor (GEF) 4
• Repac for related to Epac
• a related protein named Repac has been identified by Ichiba et al. (1999).
• Repac shows close sequence similarity to Epac 2 and lacks the regulatory sequences present in Epacl and Epac2 (Ichiba et al., 1999).
• Homo sapiens Epac 1 gene is localized on chromosome 12.
• the nucleotide and amino acids sequences of Epacl, SEQ ID NO : 1 and 2 respectively, are deposited in Genebank under accession number NM_006105.
• the nucleotide and amino acids sequences of Epac 2, SEQ ID NO : 3 and 4 respectively, are deposited in Genebank under accession number NM_007023.
• Epac 2 is mapped to human chromosome 2q31.
• the nucleotide and amino acids sequences of Repac, SEQ ID NO : 5 and 6 respectively, are deposited in Genebank under accession number BC039203.
• Repac is mapped " to human chromosome 7pl5.3. — . .. . . . . _ _
• Antisense molecules can be modified or unmodified RNA, DNA, or mixed polymer ⁇ oligonucleotides and primarily function by specifically binding to matching sequences resulting in inhibition of peptide synthesis.
• the antisense oligonucleotide binds to target RNA by Watson Crick base-pairing and blocks gene expression by preventing ribosomal translation of the bound sequences either by steric blocking or by activating RNase H enzyme.
• Antisense molecules can also alter protein synthesis by interfering with RNA processing or transport from the nucleus into the cytoplasm.
• antisense deoxyoligoribonucleotides can be used to target RNA by means of DNA-RNA interactions, thereby activating RNase H, which digests the target RNA in the duplex.
• Antisense DNA can be expressed via the use of a single stranded DNA intracellular expression vector or equivalents and variations thereof.
• Antisense nucleic acids are useful for regulating and controlling the expression of the Epac protein gene in vivo and in vitro, and are also useful for the treatment of the diseases disclosed above. Technologies related to such antisense RNAs and gene therapies are known to the skilled man.
• the novel antisense oligonucleotides complementary to any sequence of the human Epac RNA which according to the broadest definition can be of a length ranging from 7 to 40 nucleotides, have preferably a length ranging from 15 to 25 nucleotides, most preferably about 20 nucleotides.
• complementary means that the antisense oligonucleotide sequence can form hydrogen bonds with the target mRNA sequence by Watson-Crick or other base-pair interactions.
• TFO Triplex Forming Oligonucleotides
• RNP RiboNucleoProtein
• siRNAs short interfering RNAs
• siRNA refers to a short (typically less than 30 nucleotides long) double stranded RNA molecule.
• the siRNA modulates the expression of a gene to which the siRNA is' targeted.
• Selection of -a suitable -small interfering UNA (siRNA) molecule requires knowledge of the nucleotide sequence of the target mRNA, or gene from which the mRNA is transcribed.
• the siRNA molecules of the invention are typically between 10-30 nucleotides in length, and preferably between 18-23 nucleotides in length.
• the siRNA molecules may comprise a sequence identical or at least 90% identical to any portion of the target gene whose expression is to be modulated including coding and non-coding sequences.
• siRNA that can specifically suppress the expression of Epac
• the following guidelines are used according to Elbashir et al., 2002 : 1) Selection of the target region from the open reading frame (ORF) of the cDNA sequence preferably 50 to 100 nucleotides downstream of the start codon. 2) Determination of a 21 nucleotide sequence in the target mRNA that begins with an AA dinucleotide (Elbashir et al., 2001). Thus sequences are 5'-AA(N19)UU, where N is any nucleotide. Sequences must contain approximately 50% G/C. 3) Blast-search (www.ncbi.nih.
• siRNA sequences go/BLAST) the selected siRNA sequences against EST libraries or mRNA sequences of the respective organism to ensure that only a single gene is targeted. Any target sequences with more than 16 to 17 contiguous base pairs of homology to other coding sequences must be eliminated. 4) Synthesis of several siRNA sequences are advisable to control for the specificity of the knock-down experiments .
• a short hairpin RNA is a simple strain RNA, characterized in that the two ends of said RNA are complementary and can hybridize together, thus forming an artificial double strand RNA with a loop between the two ends.
• Ribozymes are RNA molecules possessing the ability to specifically cleave other single- stranded RNA. Through the modification of nucleotide sequences which encode these RNAs, it is possible to engineer molecules that recognize specific nucleotide sequences in an RNA molecule and cleave it. A major advantage of this approach is that, because the ribozymes are engineered to be sequence-specific, only mRNAs with sequences complementary to the construct containing the ribozyme are inactivated. There are two basic types of ribozymes namely, tetrahymena-type and "hammerhead" -type.
• Tetrahymena-type ribozymes recognize sequences which are four bases in length, while "hammerhead"-type ribozymes recognize base sequences from about 3 to 18 bases in length. The longer the recognition sequence, the greater the likelihood that the sequence will occur exclusively in the target mRNA species. Consequently, hammerhead-type ribozymes are preferable to tetrahymena-type ribozymes for inactivating a specific mRNA species.
• ribozyme, siRNAs, single strand DNA, or antisense oligonucleotides may be produced by expression of DNA sequences cloned into plasmid or retroviral vectors. Using ⁇ standard methodology known to those skilled in the art, it is possible to maintain the ribozyme, siRNA or antisense oligonucleotides in any convenient cloning vector.
• RNA Ribonucleic acid
• a "vector” is a replicon, such as a plasmid, cosmid, bacmid, phage or virus, to which another genetic sequence or element (either DNA or RNA) may be attached so as to bring about the replication of the attached sequence or element.
• a “replicon” is any genetic element, for example, a plasmid, cosmid, bacmid, phage or virus, that is capable of replication largely under its own control.
• a replicon may be either RNA or DNA and may be single or double stranded.
• an "expression operon” refers to a nucleic acid segment that may possess transcriptional and translational control sequences, such as promoters, enhancers, translational start signals (e. g. , ATG or AUG codons), polyadenylation signals, terminators, and the like, and which facilitate the expression of a polypeptide coding sequence in a host cell or organism.
• transcriptional and translational control sequences such as promoters, enhancers, translational start signals (e. g. , ATG or AUG codons), polyadenylation signals, terminators, and the like, and which facilitate the expression of a polypeptide coding sequence in a host cell or organism.
• the present invention relates to a method for treating a pathology selected from the list comprising cardiac hypertrophy, cardiac arrhythmias, valvulopathies, diastolic dysfunction, chronic heart failure, ischemic heart failure, and myocarditis, in a patient, comprising administering to said patient a therapeutically effective amount of at least one Ep ac antagonist.
• the invention relates to the method as defined above, wherein the antagonist is selected from the list comprising Epac activation inhibitors, Epac activity inhibitors, Epac intracellular localization disruption agents, and Epac expression inhibitors.
• the antagonist is an
• Epac activation inhibitor selected from the list comprising:
• - cAMP analogues such as cAMP derivatives or 8-(4-chlorophenylthio)-2'-O- methyladenosine-3'-5-cyclic monophosphate (8-CPT-2'-O-Me-cAMP) derivatives, - Brefeldin A or derivatives thereof.
• the daily dosage of said antagonists may be varied over a wide, range from 0.0 . 1 to
• the compositions contain 0.01, 0.05, 0.1, 0.5, 1.0, 2.5, 5.0, 10.0, 15.0, 25.0, 50.0, 100, 250 and 500 mg of the active ingredient for the symptomatic adjustment of the dosage to the patient to be treated.
• a medicament typically contains from about 0.01 mg to about 500 mg of the active ingredient, preferably from 1 mg to about 100 mg of the active ingredient.
• An effective amount of the drug is ordinarily supplied at a dosage level from 0.0002 mg/kg to about 20 mg/kg of body weight per day, especially from about 0.001 mg/kg to 10 mg/kg of body weight per day.
• the specific dose level and frequency of dosage for any particular patient may be varied and will depend upon a variety of factors including the activity of the specific compound employed, the metabolic stability, and length of action of that compound, the age, the body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the host undergoing therapy.
• the antagonist of Epac alone or in combination with another active principle, can be administered in a unit administration form, as a mixture with conventional pharmaceutical supports, to animals and human beings.
• Suitable unit administration forms comprise oral-route forms such as tablets, gel capsules, powders, granules and oral suspensions or solutions, sublingual and buccal administration forms, aerosols, implants, subcutaneous, transdermal, topical, intraperitoneal, intramuscular, intravenous, subdermal, transdermal, intrathecal and intranasal administration forms and rectal administration forms.
• the active principle is generally formulated as dosage units containing from 0.5 to 1000 mg, preferably from 1 to 500 mg, more preferably from 2 to 200 mg of said active principle per dosage unit for daily administrations.
• the invention further relates to a method as defined above, wherein the antagonist is an Epac activity inhibitor, in particular an inhibitor of the Guanine nucleotide Exchange Factor (GEF) domain of Epac, or an inhibitor of the Ras Exchange Motif (REM) domain of Epac, selected from the list comprising:
• GEF Guanine nucleotide Exchange Factor
• REM Ras Exchange Motif
• the invention also relates to a method as defined above, wherein the antagonist is an
• Epac intracellular localization disruption- agent selected from the list comprising: - - - - - - -
• Epac cellular localization domain such as the Dishevelled EgI- 10 Pleckstrin (DEP) domain
• the invention also relates to a method as defined above, wherein the antagonist is an
• Epac expression inhibitor selected from the list comprising:
• RNA double stranded RNA
• siRNA siRNA or a shRNA comprising Epac nucleic acid sequences
• the present invention relates to a pharmaceutical composition
• a pharmaceutical composition comprising as active substance an Epac expression inhibitor selected from the list comprising:
• an antisense nucleic acid directed against Epac mRNAs - a double stranded RNA, a siRNA or a sliRNA comprising Epac nucleic acid sequences,
• Ribozyme, siRNA, or antisense oligonucleotides encoding vectors and constructs as described herein are generally administered to a subject as a pharmaceutical preparation.
• the term "subject” denotes a mammal, such as a rodent, a feline, a canine, and a primate.
• a subject according to the invention is a human
• the pharmaceutical preparation comprising the ribozyme, siRNA or antisense oligonucleotides molecules or vectors are conveniently formulated for administration with an acceptable medium such as water, buffered saline, ethanol, polyol (for example, glycerol, propylene glycol, liquid polyethylene glycol and the like), dimethyl sulfoxide (DMSO), oils, detergents, suspending agents or suitable mixtures thereof.
• an acceptable medium such as water, buffered saline, ethanol, polyol (for example, glycerol, propylene glycol, liquid polyethylene glycol and the like), dimethyl sulfoxide (DMSO), oils, detergents, suspending agents or suitable mixtures thereof.
• concentration of the ribozyme, siRNA or antisense oligonucelotides molecules or vectors in the chosen medium may depend on the hydrophobic or hydrophilic nature of the medium, as well as the length and other properties of the ribozyme siRNA or antisense oligonu
• Ribozyme, siRNA or antisense oligonucleotides molecules and vectors encoding the same may be administered parenterally by intravenous injection into the blood stream, by subcutaneous, intramuscular, or intraperitoneal injection, or any other method known in the art. Pharmaceutical preparations for parenteral injection are commonly known in the art. If parenteral injection is selected as a method for administering the molecules or vectors, steps
• Ribozyme, siRNA or antisense oligonucleotides molecules of the present invention may be encapsulated in a lipophilic, targeted carrier, such as a liposome.
• a pharmaceutical preparation of the invention may be formulated in dosage unit form for ease of administration and uniformity of dosage.
• Dosage unit form refers to a physically discrete unit of the pharmaceutical preparation appropriate for the patient undergoing treatment. Each dosage should contain a quantity of active ingredient calculated to produce the desired effect in association with the selected pharmaceutical carrier. Procedures for determining the appropriate dosage unit are well known to those skilled in the ait. Dosage units may be proportionately increased or decreased based on the weight of the patient. Appropriate concentrations for alleviation of a particular pathological condition may be 5 determined by dosage concentration curve calculations, as known in the art.
• the appropriate dosage unit for the administration of ribozyme-siRNA or antisense oligonucleotides molecules may be determined by evaluating the toxicity of the ribozyme, siRNA or antisense oligonucelotides molecules in animal models.
• Various concentrations of said molecules in pharmaceutical 0 preparations may be administered to mice and the minimal and maximal dosages may be determined based on comparing obtaining desired results as opposed to side effects as a result of the treatment.
• the pharmaceutical preparation comprising the molecules may be administered at appropriate intervals, for example, twice a day until the pathological symptoms are reduced or 5 alleviated, after which the dosage may be reduced to a maintenance level.
• the pharmaceutical composition is advantageously substantially pure.
• substantially pure refers to a preparation comprising at least 50-60% by weight of a given material (e.g. nucleic acid, oligonucleotide). More preferably, the preparation comprises at least 75% by weight, and most preferably 90-95% by weight of the given compound. Purity is 0 measured by methods appropriate for the given compound (e.g. chromatographic methods, agarose or polyacrylamide gel electrophoresis, HPLC analysis, and the like).
• the invention relates in particular to pharmaceutical compositions comprising as active substance an Epac activation inhibitor, an Epac activity inhibitor, or an Epac intracellular localization disruption agent, selected from the list comprising: 5 - antibodies, fragments thereof, or aptamers, directed against Epac cAMP binding sites, ⁇ - --antibodies,- fragments thereof, or aptamers, directed .against ihe. GEF domain Q ⁇ . the REM domain of Epac,
• Epac cellular localization domain such as the DEP domain
• the invention also relates to the use of Epac for screening compounds intended for the prevention or the treatment of pathologies selected from the list comprising cardiac hypertrophy, cardiac arrhythmias, valvulopathies, diastolic dysfunction, chronic heart failure, ischemic heart failure, and myocarditis.
• Epac activation inhibitors Epac activity inhibitors
• Epac intracellular localization disruption agents Epac expression inhibitors.
• the invention further relates to a method for screening compounds intended for the prevention or the treatment of pathologies selected from the list comprising cardiac hypertrophy, cardiac arrhythmias, valvulopathies, diastolic dysfunction, chronic heart failure, ischemic heart failure, and myocarditis, comprising the steps of:
• the cAMP-dependent activation of Rapl can be assessed to determinate the percentage of Epac activation.
• the invention also relates to the method as defined above, wherein Epac is also contacted with an effector protein liable to be activated upon Epac activation, such as Rapl, Rap2, Rac or Ras, and Epac activation is assessed by measuring the activity of said effector protein.
• an effector protein liable to be activated upon Epac activation such as Rapl, Rap2, Rac or Ras
• Epac activation is assessed by measuring the activity of said effector protein.
• the screening method comprises testing in vitro the effect of the compounds to inhibit Epac-induced cAMP-dependent Rapl or Rap2 activation.
• Rapl is a well known effector of Epac.
• full-length Epac is incubated with Rapl or Rap2 loaded with fluorescenlly labelled 2', 3'-bis(O)-N-methylantharanoloyl-guanosinediphosphate (mGDP) and the release of mGDP is detected in real time by a fluorescence spectrometer as previously described (Van den Berghe et al., 1997).
• the inhibition effect of the compounds on Epac-induced cAMP-dependent Ras or Rac activation can be assessed using GST pull down assay as previously described (Maillet et al., 2003).
• the present invention relates to a method for screening compounds intended for the prevention or the treatment of pathologies selected from the list comprising cardiac hypertrophy, cardiac arrhythmias, valvulopathies, diastolic dysfunction, chronic heart failure, ischemic heart failure, and myocarditis comprising the steps of:
• cardiomyocytes having increased Epac activity as compared to normal cardiomyocytes with compounds to screen, - assessing the hypertrophic properties of said cardiomyocytes having increased Epac activity
• the screening method involves the step of: a) providing cardiomyocytes that express an activated form of Epac b) exposing said cardiomyocyte to one of the compounds to be tested c) assessing the effects of said compound on the hypetrophic properties of said cardiomyocytes, the hypertrophic properties being determined by measuring cell size and / or the expression of rnRNA coding for hypertrophic gene markers, such as the natriuretic factor.
• the cardiomyocytes that have an increased Epac activity as compared to normal cardiomyocytes express for example a wild type form of Epac or a constitutive activated form of Epac lacking its cAMP binding domain.
• the inhibition of the hypertrophic properties indicates that said compound is an antagonist of Epac.
• Administration of vectors producing ribozvme, siRNA or antisense oligonucleotides is an antagonist of Epac.
• cardiac cells may be administered to cardiac cells " or cardiac cell lines by any method- such as, without limitation, transfection, electroporation, lipofection, and transduction.
• the screening method can result in the combination of the two above described methods.
• the invention further relates to the method as defined above, wherein the compounds to screen are:
• - cAMP analogues such as cAMP derivatives or 8-(4-chlorophenylthio)-2'-O- methyladenosine-3'-5-cyclic monophosphate (8-CPT-2'-O-Me-cAMP) derivatives, or
• a further object of the invention resides in a method for screening a compound, and especially a cAMP analog, that affects the activation of Epac.
• the present invention relates to a non-human transgenic mammal for use as a model of cardiac hypertrophy, wherein Epac activity is increased with respect the corresponding wild type non-human mammal.
• cardiac hypertrophy has been induced by the specific expression of a positive dominant form of Epac, and especially Epacl in cardiomycoytes.
• the invention relates in particular to a non-human transgenic mammal for use as a model of cardiac hypertrophy as defined above, wherein Epac is over-expressed with respect the corresponding wild type non-human mammal, in particular said non-human transgenic mammal comprises Epac coding sequences under the control of cardiac-specific promoters having a stronger transcription activity than Epac natural promoter, such as the promoter of the ⁇ -Myosin Heavy Chain.
• the positive dominant form of Epac is under the control of a cardiac specific promoter such as ⁇ -Myosin Heavy Chain.
• the invention further relates to a non-human transgenic mammal for use as a model of cardiac hypertrophy as defined above, wherein said non-human transgenic mammal comprises nucleic sequences encoding a constitutively activated form of Epac lacking the activating cAMP binding domain.
• Epac- ⁇ cAMP which contains a deletion of the first 322 amino acids of Epacl (de Rooij et al., 1998).
• Epac- ⁇ cAMP lacks the cAMP -binding domain and therefore behaves as a constitutive activated form of Epac and cannot be regulated by cAMP (de Rooij et al., 1998).
• the invention also relates to a non-human transgenic mammal for use as a model of cardiac hypertrophy as defined above, wherein said mammal is a mouse.
• compositions containing the Epac antagonist(s) can be administered for prophylactic and/or therapeutic treatments.
• the active ingredient in the pharmaceutical composition generally is present in an "effective amount".
• an “effective amount” of a pharmaceutical composition is meant a sufficient, but nontoxic amount of the agent to provide the desired effect.
• the term refers to an amount sufficient to treat a subject (e.g., a mammal, particularly a human).
• therapeutic amount refers to an amount sufficient to remedy a disease state or symptoms, by preventing, hindering, retarding or reversing the
• prophylactically effective amount refers to an amount given to a subject that does not yet present the symptoms of cardiac hypertrophy, and thus is an amount effective to prevent, hinder or retard the onset of cardiac hypertrophy.
• cardiac hypertrophy The symptoms of cardiac hypertrophy include shortness of breath on exertion, dizziness, fainting and angina pectoris. (Angina is chest pain or discomfort caused by reduced blood supply to the heart muscle.) Some people have cardiac arrhythmias. These are abnormal heart rhythms that in some cases can lead to sudden death. The obstruction to blood flow from the left ventricle increases the ventricle's work, and a heart murmur may be heard. In the majority of patients with hypertrophic cardiomyopathy, the physical examination is unremarkable and the abnormalities may be subtle. Most patients have forceful or jerky pulse and a forceful heart beat, which can be felt on the left side of the chest. Both of these reflect the thickened, strongly contracting heart.
• ECG electrocardiogram
• MRI Magnetic Resonance Imaging
• a cardiac MRI may be better than an echocardiogram to reliably detect hypertrophy in areas such as the left ventricular anterolateral wall and apex.
• an echocardiogram may not be sufficient to confidently exclude a diagnosis of cardiac hypertrophy and in that situation a - cardiac MRI may be recommended.
• compositions are administered to a patient already suffering from a disease, as just described, in an amount sufficient to cure or at least partially arrest the symptoms of the disease and its complications.
• An appropriate dosage of the pharmaceutical composition is readily determined according to any one of several well-established protocols. For example, animal studies (e.g., mice, rats) are commonly used to determine the maximal tolerable dose of the bioactive agent per kilogram of weight. In general, at least one of the animal species tested is mammalian. The results from the animal studies can be extrapolated to determine doses for use in other species, such as humans for example. What constitutes an effective dose also depends on the nature and severity of the disease or condition, and on the general state of the patient's health.
• compositions containing at least one Epac antagonists are administered to a patient susceptible to or otherwise at risk of a cardiac hypertrophy.
• Such an amount is defined to be a "prophylactically effective" amount or dose.
• the precise amounts again depend on the patient's state of health and weight.
• Epac activates the small G protein Rac in primary rat ventricular cardiomyocytes and HL-I atria cells.
• Figure IA Primary rat ventricular cardiomyocytes were infected with either Ad.GFP as a control or with Ad.EpacWT or Ad.Epac- ⁇ cAMP as described in Methods. Two days after infection, cells were treated or not for 10 min with the selective activator of Epac, 8-CPT (1 ⁇ M). Amounts of Rac-GTP were determined by pull down experiments. A control for total Rac expression (total lysates) is shown. The upper panel shows a typical immunoblot. Expression of recombinant proteins was determined by Western blot using an anti-HA antibody. The lower panel shows means ⁇ S.E.M. of 3 independent experiments. Results are expressed as fold activation of control cells infected with Ad.GFP.
• FIG. 1B HL-I atrial cells were treated with 8-CPT (iOO ⁇ M), Forskolin (FSK) (100 ⁇ M), or 8-Br-cAMP (10 ⁇ M) for 10 -min.
• The- upper panel shows a representative immunoblot.
• FIG.C Effect of 8-CPT (10 ⁇ M) at different time of incubation on the amount of Rac- GTP. Rac activation was determined as above. Control for total lysates (Total Rac) is shown.
• FIGS 2 A, 2C and 2D Neonatal cardiomycoytes were transfected with ANF-Luc (Figure 2A), SlcM- ⁇ -actin-Luc ( Figure 2C) or c-fos-SRE-Luc ( Figure 2D) and EpacWT, RacG12V or the empty vector (mock) as control and treated or not with 8-CPT (1 ⁇ M). Two days after transfection, cells were assayed for luciferase activity. Results are expressed as percentage activation of control. Results are means ⁇ S.E.M. for 3 independent experiments performed in triplicates.
• FIG. 2B Epac induces expression of ANF mRNA. Cardiomyocytes were infected with
• Ad.EpacWT Ad.RacG12V
• Ad.GFF control
• 8-CPT 8-CPT
• Figure 3A, Figure 3B, Figure 3C, Figure 3D and Figure 3E Epac induces cardiomyocytes hypertrophy in neonatal ( Figures 3 A, 3B and 3C) and adult ( Figure 3D and 3E) rat primary cardiomyocytes.
• FIG. 3A Fluorescent microscopic analyses of the effects of. Epac on sarcomeric organization. Morphology of representative myocytes 48 h after infection with Ad. GFP as a control, or Ad.EpacWT is shown. The Epac selective activator, 8-CPT, was used at 1 ⁇ M for 2 days in cells infected with Ad.GFP. For a positive control, cells were infected with Ad.GFP and treated with PE (1 ⁇ M) for 2 days. Actin filaments were visualized by using Rhodamin- conjugated phalloidin.
• Figure 3B Photographic images of cells infected for 2 days with Ad.GFP or Ad.EpacWT and treated or not with either 8-CPT (1 ⁇ M) or PE (1 ⁇ M) were digitised. The areas ( ⁇ m 2 ) of 30 to • 50 individualized cells per condition from 2 to 3 independent experiments were determined by computer- assisted planimetry. Values show the means - ⁇ S.E.M. -
• FIG. 3C [ 3 H] -leucine incorporation. Cardiomyocytes were treated as above and total radioactivity of incorporated [ H]-leucine into proteins was determined by scintillation counting. The figure shows the mean ⁇ S.E.M. of data for 3 experiments performed in duplicate. *p ⁇ 0.05, **p ⁇ 0.01, ***p ⁇ 0.001 compared with control Ad.GFP.
• Figure 3D ⁇ -actinin staining of cardiac myocytes infected with the Ad.GFP or the Ad.Epac WT and GFP, or Ad.Epac dcAMP , or Ad.Ra ⁇ Q63E , treated or not with an agonist of Epac, 8-CPT. Morphology of representative myocytes 48 h after infection with Ad.GFP as a control, Ad.Epac WT /GFP or Ad.Rap Q63E is shown. The Epac selective activator, 8-CPT was used at 1 ⁇ ⁇ M for 2 days, ⁇ -actinin was visualized by immunocytochemistry as described in Methods.
• FIG. 3E Photographic images of rat adult cardiac myocytes infected for 2 days with the Ad. GFP, or Ad.Epac WT , or Ad.Epac dcAMP or Ad.Rap Q63E and treated or not with 8-CPT (1 ⁇ M) and were digitized.
• the surface, the length, and the width of around 100 individualized cells per condition from 5 to 6 independent experiments were determined by computer-assisted planimetry. Values show the means ⁇ S.E.M.
• Epac induces intracellular Ca2+ transients and Ca2+ activates Rac.
• hi figures 4A, 4B, 4C and4D neonatal cardiomyocytes at day 1 or 2 after plating were loaded with the Ca2+ indicator Fluo3-AM and perfused with a control external ringer solution.
• Figure 4A Effect of 10 ⁇ M 8-pCPT-2'-O-Me-cAMP (8-CPT) on spontaneous spiking activity at 1.8 mM external [Ca 2+ ] .
• Figure 4B Effect of 10 ⁇ M 8-CPT in the presence of 20 mM external Cs + .
• Figure 4C Effect of 100 ⁇ M 8-CPT in the absence of external Ca 2+ .
• Figure 4D Effect of 100 ⁇ M 8-CPT in the absence of external Ca 2+ and presence of the PKA blocker H89 (1 ⁇ M).
• Figure 4E Effect of ionomycin on Rac activation. Primary rat ventricular cardiomyocytes were treated at 2 days in vitro with ionomycin (1 ⁇ M) for different times of incubation of PE
• FIGs 5 A and Figure 5B Effect of Epac on NFAT transcriptional activity. Cardiomyocytes infected with Ad.GFP (control), Ad.EpacWT, or Ad. VIVIT were transfected with NFAT-Luc and treated ' or not with CsA (0,5 ⁇ M) for 48 h. Luc activity was assayed as described in Methods.
• Ad.GFP control
• Ad.EpacWT Ad.EpacWT
• Ad. VIVIT were transfected with NFAT-Luc and treated ' or not with CsA (0,5 ⁇ M) for 48 h. Luc activity was assayed as described in Methods.
• FIG. 5 C Epac increases MCIPl expression. Cardiac myocytes infected with Ad.GFP (control) or Ad.EpacWT were treated or not with 8-CPT (1 ⁇ M) for 2 days. The ratio of MCIPl/GCB niRNA was determined by quantitative PCR. Values are expressed relative to the MCIPl/GCB ratio. Results were normalized to control for each experiment, and were expressed as means ⁇ S.E.M of at least 3 independent experiments performed in triplicate ( Figures 5 A and 5B) or duplicate ( Figure 5C).
• Ad.VIVIT inhibits Epac-induced cardiomyocyte hypertrophy
• FIG. 6A Fluorescent microscopic analyses of the effects of Epac on sarcomeric organization. Morphology of representative myocytes 48 h after infection with Ad. GFP as a control, Ad.VIVIT, Ad.EpacWT, or Ad.EpacWT and Ad.VIVIT is shown.
• Figure 6B Photographic images of cardiac myocytes infected as above were digitised. Areas ( ⁇ m 2 ) of around 50 individualized cells per condition from 3 independent experiments were determined by computer-assisted planimetry. Values show the means ⁇ S.E.M. *p ⁇ 0.05, **p ⁇ 0.01 and *** pO.OOl compared with control or versus indicated values.
• Epac activates CaMKII signaling pathway.
• FIGS 7A Epac regulates MEF2 transcriptional activity. Cardiomyocytes infected with Ad. GFP (control), Ad.EpacWT, or Ad.Epac ⁇ cAMP were transfected with MEF2-Luc and treated or not with CsA (0,5 ⁇ M) for 48 h. Luc activity was assayed as described in Methods.
• Figure 7B Epac regulates MEF2 transcriptional activity. Cardiomyocytes infected with Ad.GFP (control), Ad.EpacWT, or Ad.Epac ⁇ cAMP were transfected with MEF2-Luc and treated or not with KN-93 (1 ⁇ M) for 48 h. Luc activity was assayed as described in Methods.
• FIG. 7C KN-93 inhibits Epac-induced cardiomyocyte hypertrophy. Cardiomyocytes infected with Ad.GFP (control), or Ad.Epac ⁇ cAMP and treated or not with KN-93 (1 ⁇ M) for 2 days were stained with phalloidin. Photographic images were then taken and digitised.
• Ad.GFP control
• Ad.Epac ⁇ cAMP Ad.Epac ⁇ cAMP
• FIGS 8 A, 8B and 8C cardiomyocytes infected with Ad.GFP (control), Ad.RacS17N,
• Ad.EpacWT, or Ad.EpacWT and Ad.RacS17N were transfected with NFAT-Luc, MEF2-Luc or ANF-Luc. Two days after, Luc activity was determined. Luc activity was normalized to control for each experiment, and were expressed as means ⁇ S.E.M of at least 3 separate experiments performed in triplicate
• Ad.RacS17N reverses Epac-induced cardiomyocyte hypertrophy.
• Figure 9A Photographic images of cells infected for 2 days with Ad.GFP (control), Ad.EpacWT, Ad.RacS17N, or Ad.EpacWT and Ad.RacS17N were digitised.
• Figure 9B The areas ( ⁇ m ) of 50 individualized cells per condition from 3 independent experiments were determined by computer-assisted planimetry. Values show the means ⁇ S.E.M. *p ⁇ 0.05, **p ⁇ 0.01 and *** ⁇ .001 versus control cells or indicated values.
• Gs-coupled receptor activates the adenylyl cyclase (AC) which increases intracellular cAMP levels. Subsequent activation of Epac induces a rise in [Ca2+]i which increases Rac activation.
• the small G protein Rac can both induce cytoskeletal reorganization and activation of the calcineurin / NFAT signaling pathway. Epac also regulates MEF2 transcriptional activity via CaMKII. Epac signaling pathway induces hypertrophic gene expression and cardiomyocyte growth.
• FIG. 12 Activation of Epacl increases protein synthesis in adult rat primary cardiomyocyte.
• Cardiomyocytes- were infected with the Ad.GFP (control), or the Ad.Ep_ac WT and GFP, or Ad.Rap Q63E , treated or not with an agonist of Epac, 8-CPT, and total radioactivity of incorporated [3H]-leucine into proteins was determined by scintillation counting.
• the Epac selective activator, 8-CPT was used at 1 ⁇ M for 2 days.
• As a positive control cells were treated with the hypertrophic stimulus, phenylephrine for 2 days (1 ⁇ M).
• the figure shows the mean ⁇ S.E.M. of data for 3 experiments performed in duplicate. *p ⁇ 0.05, **p ⁇ 0.01, compared with control Ad.GFP.
• Figure 12 shows the mean ⁇ S.E.M. of data for 3 experiments performed in duplicate. *p ⁇ 0.05, **p ⁇ 0.01, compared with control Ad.GFP.
• EXAMPLE 1 The cAMP-binding protein Epac induces cardiomyocyte hypertrophy Materials and Methods Materials All media, sera and antibiotics used in the cell culture were purchased from Invitrogen
• HL-I atrial cardiomyocytes a gift from Dr. Claycomb (Louisiana State University, New Jersey, LA, U.S.A.) were plated onto fibronectin-gelatin-coated plates or coverslips and cultured in Claycomb medium supplemented with 10% fetal bovine serum, 100 units/ml penicillin, 100 ⁇ g/ml streptomycin, 0.1 mM norepinephrine, and 2 mM L-glutamine as described (Claycomb et al, 1998).
• Neonatal rat ventricular myocytes were isolated according to the protocol described by
• the cell suspension was purified by centfifugation through a discontinuous Percoll gradient (Sigma Aldrich, L'Isle d'Abeau
• Cardiomyocytes were plated in gelatin-coated culture dishes in Dubelcco's modified Eagle's medium (DMEM)/medium 199 (4/1) supplemented with 10 % horse serum (v/v), 5% newborn calf serum (v/v), glutamine and antibiotics. The day after, cardiomyocytes were switched to the maintenance medium composed of DMEM/medium 199 supplemented only with glutamine and antibiotics.
• DMEM Dubelcco's modified Eagle's medium
• medium 199 4/1
• the day after, cardiomyocytes were switched to the maintenance medium composed of DMEM/medium 199 supplemented only with glutamine and antibiotics.
• Rat ventricular myocytes were isolated from male Wistar rats (160-180 g). The rats were subjected to anesthesia by intraperitoneal injection of pentothal (0.1 mg/g), and hearts were excised rapidly, individual ventricular myocytes were obtained by retrograde perfusion of the heart as previously described (Verde et al., 1999).
• Freshly isolated cells were suspended in minimal essential medium (MEM: M 4780; Sigma) containing 1.2 mM Ca 2+ , 2.5% fetal bovine serum (FBS, Invitrogen, Cergy-Pontoise, France), 1% penicillin- streptomycin and 2% HEPES (pH 7.6) and plated on laminin-coated culture dishes (10 ⁇ g/ml laminin, 2 h) at a density of 10 5 cells per dish. The cells were left to adhere for 1 h in a 95% O 2 , 5% CO 2 incubator at 37 °C before adenoviral infection.
• MEM minimal essential medium
• FBS Invitrogen, Cergy-Pontoise, France
• HEPES HEPES
• Bicistronic adenoviruses bearing either EpacWT or Epac ⁇ cAMP under the control of a cytomegalovirus (CMV) promoter, and green fluorescent protein (GFP) under internal ribosomal entry site (IRES) control were constructed and amplified at the Genethon Center of " Evry (France) ( Figure 13).
• Adenoviruses encoding- VIVIT, a selective peptide inhibitor of calcineurm-mediated NFAT activation, and Rac were provided by Drs. J. Molkentin and T. Finkel, respectively.
• cardiomyocytes were incubated for 2 h with recombinant adenoviruses. After removal of the virus suspension, cells were , replaced in maintenance medium for 2 days and then stimulated with the different drugs.
• Viruses were used at a multiplicity of infection (MOI) of 100.
• Rapl Q63E or Ad.GFP were used at a multiplicity of infection (MOI) of 100 plaque-forming units (pfu) per cell, whereas Ad.Epac ⁇ cAMP was generally used at 500 MOI (see results).
• MOI multiplicity of infection
• the plasmid constructs were generously provided by the following: a -3003 bp fragment of the rat ANF promoter fused to the luciferase reporter gene (ANF-Luc) by Dr. K. Knowlton, Luciferase reporter genes linked to promoters for skeletal muscle ⁇ -actin (SkM- ⁇ - actin-Luc) and serum response element-regulated c-fos (c-fos-SRE-Luc) by Dr. M. D. Schneider, Epacl plasmid constructs by Dr. J. Bos.
• NFAT-Luc The luciferase reporter plasmid driven by four NFAT consensus binding sites (NFAT-Luc) or driven by the three MEF2 consensus binding sites (MEF2-Luc) was obtained from Stratagene and was kindly provided by Dr KC Wollert respectively. Transient transfection experiments were performed with Lipofectamine 2000 (Invitrogen Life Technologies, France) in optimem medium in the presence of 1 mg of the various plasmid constructs according to the manufacturer's instructions.
• Cardiomyocytes were plated in Lab-Tek plastic chamber slides (Nunc), precoated with gelatin (0.2%) and incubated in the presence or absence of various agents. After 48 h, cells were rinsed three times with PBS containing 1% BSA and fixed by immersion in 4% , paraformaldehyde during 30 min.
• cardiomyocytes were incubated with a 1/800 diluted solution of rhodamine phalloidine (Sigma Aldrich, L'isle d' Abeau Chesmes, France) for 45 min with gentle shaking.
• rhodamine phalloidine Sigma Aldrich, L'isle d' Abeau Chesmes, France
• cardiac actin organization was assessed by the following protocol: myocytes were incubated with 0.2% Triton X-100 for 5 min, followed by 0.5 mol / L NH 4 Cl in PBS for 15 min. After a preincubation in 5% bovine serum albumin in PBS for 30 min, myocytes were incubated overnight with a mouse monoclonal antibody directed against cardiac sarcomeric ⁇ -actinin (cloneEA-53, 1/300, Sigma, France). The secondary antibody used was a goat anti-mouse IgG coupled to Alexa Fluor®594 (1/150, Molecular Probes).
• Neonatal rat ventricular myocytes at day 1 to 2 after isolation were loaded with the Ca2+ indicator Fluo 3 AM (Molecular Probes, 10 ⁇ M, 30 mm, 37°C) in serum-free maintenance medium, and then washed for additional 30 min in external ringer solution containing (niM) NaCl 121, KCl 5.4, Hepes 10, Glucose 5, Na-pyravate 5, NaHCO3 4, Na2HPO4 0.8, MgC12 1.8, CaC12 1.8 . Experiments were carried out in this solution or in the ringer solution with 100 ⁇ M EGTA and without added Ca2+ and Mg2+ and.
• Quantitative RT-PCR was conducted with a LightCycler system (Roche) using a LightCycler-FastStart DNA Master SYBR Green I kit (Roche) and specific primer pair for human Epacl (5'- GCTCTTTGAACCACACAGCA -3'; 5'-TGTCTTCTCGCAGGATGATG -3'), or ANF (5'- GGGCTee ⁇ eTCCATCACCAA-3 '-; ⁇ 5' -CTTCATGGGTCTGCTeGCTC A-3 ')- or MClPl
• PCR reactions were performed using the following cycle conditions: denaturation for 10 sec at 95 0 C, annealing for 5 s at 60°C and extension for 11 sec at 72°C. Dissociation curves were generated after each PCR run to ensure that a single specific product was amplified.
• Glucocerebrosidase (GCB) was measured as a reference gene using the primer pair 5'- GCACAACTTCAGCCTCCCAGA-3' and 5'-CTTCCCATTCACCGCTCCATT-S' .
• Results are expressed as means ⁇ SEM. Differences between groups have been analyzed by one-way ANOVA followed by unpaired Student's t test. Differences were considered significant when * PO.05, ** P ⁇ 0.01, *** PO.001.
• Epac activates the small G protein Rac in cardiomyocytes
• the Inventors directly assayed Rac GTP-loading using a glutathione S-transferase (GST) fusion protein containing the Cdc42-Rac interactive binding domain (CRIB) of p21- activated kinase (PAK).
• GST glutathione S-transferase
• Cdc42-Rac interactive binding domain Cdc42-Rac interactive binding domain
• PAK p21- activated kinase
• Ad.EpacWT had similar effects on Rac activity as observed for Ad.Epac- ⁇ cAMP could be explained by its activation with endogenous cAMP.
• the regulation of Rac activity by Epac was not restricted to ventricular cardiomyocytes since a 10 min exposure of HL-I adult mouse atrial cells to 8-CPT (100 ⁇ M) caused a strong increase in the amount of Rac-GTP (Figure IB). In this cell line, 8-CPT-induced Rac activation was detected upon 5 min treatment with this cAMP analogue (Figure 1C).
• Figure 2A shows a three fold activation of the ANF- Luc reporter gene in neonatal cardiomyocytes stimulated with 8-CPT (1 ⁇ M) compared to control cells.
• Transient transfection of EpaclWT as well as 8-CPT (1 ⁇ M) increased the basal level of ANF-Luc activity (Figure 2AV A constitutive activated form of Rac (RacG12V) mimicked the effect of Epac on ANF-Luc activity ( Figure 2A).
• endogenous expression of ANF mRNA was significantly increased in ventricular cardiomyocytes infected with Ad.EpacWT and stimulated or not with 8-CPT (1 ⁇ M), as compared to cell infected with control Ad. GFP ( Figure 2B).
• HCN channels underlie the pacemaker current If which is an important contributor of automaticity in neonatal ventricular cells (Er et al, 2003). If is directly regulated by cAMP and its activation by the cAMP analogue, 8-CPT would be expected to increase spontaneous diastolic depolarisation and rhythmic activity.
• VIVIT an adenovirus bearing a selective peptide inhibitor of calcineurin named VIVIT (Aramburu et al, 1999), blocked the stimulating effect of Ad.EpacWT on NFAT transcriptional activity (Figure 5B).
• the Inventors found that cardiac myocytes infected with Ad.EpacWT and treated or not with ⁇ 8-CPT ⁇ (l ⁇ M) ( Figure 5C), or Ad.Epac-DcAMP (data not shown) had an increased mRNA encoding the modulatory calcineurin-interacting protein 1 (MCIPl), a mediator of calcineurin signaling during cardiac hypertrophy (Yang et al, 2000).
• MCIPl modulatory calcineurin-interacting protein 1
• Epacl is increased inpatients with heart failure
• Epacl mRNA expression is significantly increased in patients with heart failure as compared to control samples.
• Epac activates a prohypertrophic signaling pathway which involves the Ca2+ sensitive phosphatase, calcineurin and its primary downstream effector, NFAT as well as MEF2. Epac-induced NFAT activation was dependent of Rac activity.
• the Inventors found that the Epac-specific activator, 8-CPT induced Rac activation in primary cardiomyocytes and HL-I cells. In addition, the Inventors showed that Epac WT or Epac- ⁇ cAMP expression also enhanced Rac activation in rat cardiomyocytes. This is in accordance with the recent findings of the Inventors showing that Epac induces Rac activation in a cAMP-dependent but PKA-independent manner in non-cardiac cells such as primary cortical neurons and CHO cells (Maillet et al, 2003). As the Inventors found that Rac was activated by Ca2+ following Epac stimulation, it is reasonable to think that Rac might be regulated by a GEF which is sensitive to Ca2+.
• RhoGDI Rho GDP- dissociation inhibitor
• Epac up-regulates the expression of MCIPl, a well known modulator of calcineurin signaling which possesses a series of NFAT binding sites in its gene promoter (Vega et al, 2002; Yang et al, 2000).
• Ad Ad.
• the Inventors propose a new cAMP signaling pathway in which a prolonged activation of Epac leads to a sustained increase in [Ca2+]i which then activates CaMKII and Rac.
• the latter increases calcineurin/NFAT activation.
• This signaling cascade activates hypertrophic gene expression and induces the morphological aspects of cardiac myocyte hypertrophy ( Figure 10).
• EXAMPLE 2 Construction of siRNAs that specifically inhibit the expression of Epac
• ⁇ guidelines are used according to Elbashir et al., 2002 : 1) Selection of the target region from the open reading frame (ORF) of the cDNA sequence preferably 50 to 100 nucleotides downstream of the start codon. 2) Determination of a 21 nucleotide sequence in the target mRNA that begins with an AA dinucleotide (Elbashir et al., 2001). Thus sequences are 5'- AA(N19)UU, where N is any nucleotide. Sequences must contain approximately 50% G/C. 3) Blast-search (www.ncbi.nih.
• siRNA sequences go/BLAST) the selected siRNA sequences against EST libraries or mRNA sequences of the respective organism to ensure that only a single gene is targeted. Any target sequences with more than 16 to 17 contiguous base pairs of homology to other coding sequences must be eliminated. 4) Synthesis of several siRNA sequences are advisable to control for the specificity of the knock-down experiments. Then A) the software of Qiagen company or the software "online target finder" of the custom chemical synthesis service for siRNA present on the website of the RNA company Ambion is used to design potential sequences based on the guidelines described above.
• siRNA duplexes ready to use for RNAi transfection experiments.
• Annealing can be performed as follows: incubation of equimolecular concentration of oligonucleotides (20 ⁇ M) in annealing buffer for 1 min at 90°C, centrimgation (15s) and incubation at 37°C for Ih.
• the siRNA duplex (20 ⁇ M) is ready to use for RNAi experiments and can be stored at -20°C and undergo multiple freeze-thaw cycles.
• E The effect of silencing of the several isoforms of Epac (Epacl accession number NM_006105 of sequence SEQ ID NO : 1, E ⁇ ac2 NM_007023 of sequence SEQ ID NO : 3 and Repac BC_039203 of sequence SEQ ID NO : 5) is investigated on various parameters of cardiac hypertrophy (cell size, hypertrophic gene markers) upon cardiomyocytes treatment with various hypertrophic stimuli (i.e : isoproterenol, angiotensin II, phenylephrine, endotheline-1), in the aim of future applications in human cardio-physiopathology.
• EXAMPLE 3 Non human model of cardiac hypertrophy induced by Epac.
• Epac- ⁇ cAMP a positive dominant form of Epacl
• the cDNA coding for the human form of Epacl lacking its first 322 amino acids (Epac ⁇ cAMP) and containing a HA epitope in its N terminus (de Rooij et ah, Nature 396: 474-477) was fused to the ⁇ -Myosin Heavy Chain cardiac specific promoter (Gulick et al, 1991) ( Figure 14Y
• the plasmid construct containing the, ⁇ -Myosin Heavy Chain promoter cloned upstream HA-Epac- ⁇ cAMP ( Figure 14) is then linearized and inserted into the Hypoxanthine PhosphoRibosylTransferase ⁇ hprt) locus of BPES cells hprt negative, according to the technique described by Farhadi et al.
• Epac is a Rapl guanine-nucleotide-exchange factor directly activated by cyclic AMP. Nature 396: 474-477
• Epac A new cAMP -binding protein in support of glucagon-like peptide-1 receptor-mediated signal transduction in the pancreatic beta-cell. Diabetes 53: 5-13
• JNK c-Jun N-terminal kinases
• Luttrell LM Activation and targeting of mitogen-activated protein kinases by G-protein- coupled receptors.
• Cardiotrophin-1 activates a distinct form of cardiac muscle cell hypertrophy. Assembly of sarcomeric units in series VIA gpl30/leukemia inhibitory factor receptor-dependent pathways. J Biol Chem 271 : 9535-9545

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