Remedies for heart failure

FIELD OF THE INVENTION

[0002] The present invention relates to prophylactic or therapeutic agents for heart failure, methods for screening substances suitable as active ingredients of the prophylactic or therapeutic agents, diagnostic agents or diagnostic kits for heart failure and non-human transgenic animals, etc.

BACKGROUND OF THE INVENTION

[0003] Chronic heart failure is a disease in which the heart cannot maintain an adequate cardiac output to various organs due to reduced myocardial contractility, and conventional therapies therefor include the use of cardiac stimulants that increase myocardial contractility such as digitalis and xanthine drugs. However, these drugs have been shown to adversely affect vital prognosis as a result of increased consumption of myocardial energy during prolonged administration. Recently, therapies with β-blockers or ACE inhibitors have prevailed that reduce overload on the heart caused by over activation of the sympathetic nervous system or the renin-angiotensin system in patients with heart failure. However, long-term vital prognosis of patients with heart failure is still poor and it would be desirable to develop a drug for treating heart failure based on a new mechanism.

SUMMARY OF THE INVENTION

[0004] Thus, the present invention aims to provide a novel prophylactic or therapeutic agent for heart failure or the like based on a different mechanism from existing ones. More specifically, the present invention aims to provide a drug for preventing or treating heart failure by inhibiting aggravation of heart disease induced by OSF-2 gene or protein, a method for screening a substance suitable as an active ingredient of said drug, a useful diagnostic method for heart failure comprising monitoring the expression or variation of OSF-2 gene or the production of OSF-2 protein and a diagnostic agent or a diagnostic kit used for diagnosing heart failure, and a non-human transgenic animal capable of forced expression of OSF-2 gene.

[0005] On the hypothesis that the expression of various genes or proteins in the heart varies with the progress of the pathology of heart failure and that these variations are closely related to the pathology of heart failure, we searched for genes whose expression level varies with the progress of the pathology of heart failure using appropriate heart failure models. As a result, we found that the expression of OSF-2 gene known as a gene specifically expressed in osteoblasts increases with the progress of heart failure. Further studies revealed that said gene or protein influences aggravation of heart failure, which led us to accomplish the present invention on the basis that any drug inhibiting the expression or function thereof should be a novel therapy for heart failure.

[0006] In the development of therapeutic agents for heart failure, various pathologic models are used, and especially in initial screening, rat models are often used because of the convenience of preparation of the models or easy analysis. In other words, rat models are accepted as models reflecting human pathologies though they individually have limitations.

[0007] Known pathologic model rats of heart failure include aortostenotic rats, arteriovenous shunt rats, coronary artery ligature rats, spontaneously hypertensive rats (SHR), Dahl salt-sensitive rats, etc. Dahl rats are Sprague-Dawley strain rats separated into salt-sensitive rats (Dahl-S) susceptible to hypertension and salt-resistant rats (Dahl-R) resistant to hypertension at the third generation of crossing while being raised on an 8% high salt diet. Kihara et al. of Kyoto University showed that Dahl-S rats raised on an 8% high salt diet from 6-weeks of age developed compensatory left ventricular hyperttrophy, then left ventricular dilatation accompanied by contraction failure, i.e. uncompensated heart failure, and finally died of pulmonary congestion (Am. J. Physiol., 267, H2471-2482 (1994)). We selected Dahl salt-sensitive rats as pathologic models of heart failure because they can be prepared without any special techniques and can shortly develop heart failure and also can be clearly separated between compensatory hypertrophy stage and uncompensated heart failure stage in each individual and show a similar onset process to that of human hypertensive heart failure.

[0008] Known methods for detecting a gene with varied expression in pathological conditions include subtraction, differential display, dot blotting and microarray techniques. In the present invention, subtraction technique was used to succeed in detecting genes whose expression varies at the transition from cardiac hypertrophy stage to heart failure stage. They included a novel rat OSF-2 gene shown to have a high homology to the mouse OSF-2 gene that had been reported as an osteoblast-specific factor.

[0009] OSF-2 gene was isolated and identified as a gene specifically expressed in the mouse osteoblast cell line MC3T3-E1 (Biochem. J. 294, 271-278, 1993, JPA 1993/268982), and reported to have adhesion-promoting activity in osteoblast cells (J. Bone. Miner. Res. 14 1239-1249, 1999). An increased expression of OSF-2 gene has been reported in an analysis by differential display in rabbit abdominal aorta lesion models (J. Hum. Genet. 43, 9-13, 1998). Recent reports also showed that the expression of 30 or more genes including OSF-2 varied at cardiac hypertrophy stage in experiments using mice (J. Mol. Cell. Cardiol., 32, 805-815, 2000) and that the expression of 200 or more genes including OSF-2 varied in a rat myocardial infarct model (Circ. Res., 86, 939-945, 2000).

[0010] However, it has not been known until now that further expression is induced with the progress to the pathology of heart failure after cardiac hypertrophy or myocardial infarct, and nothing has been known especially about whether OSF-2 gene or OSF-2 protein acts as a factor promoting or inhibiting the progress of the pathology with the progress of the pathology of heart failure.

[0011] We thought that a novel therapeutic agent for heart failure could be developed by determining the relation of the expression of this gene in the heart to the pathology of heart failure, and accomplished the present invention after extensive studies.

[0012] Initially, we studied the expression of OSF-2 gene with the progress of the pathology of heart failure using aortostenotic rats, arteriovenous shunt rats and spontaneously hypertensive rats (SHR) to confirm that the variation in OSF-2 gene is not specific to Dahl heart failure model rats. As a result, all the models tested showed similar increased gene expression, strongly suggesting that such variations may be a universal event in the pathology of heart failure.

[0013] Then, OSF-2 gene was introduced into the rat heart in order to examine the action shown by OSF-2 gene on the heart. At first, a full-length rat OSF-2 gene was newly isolated, because rat OSF-2 gene had been so far unknown. The gene was inserted in a suitable expression vector, and introduced into rat heart. Echocardiography and hemodynamic tests showed that congestive cardiomyopathy-like pathology was induced in rats introduced with OSF-2 gene as demonstrated by thinned left ventricular wall, enlarged left ventricular lumen and decreased cardiac function, indicating that OSF-2 gene or OSF-2 protein is an aggravating factor of heart failure. The isolation of the rat gene is noteworthy because these analyses are difficult in other animals than rats. It was also shown that death by heart failure was retarded by introducing an antisense nucleotide inhibiting the expression of OSF-2 gene into the heart of a Dahl rat heart failure model. This revealed that heart failure is aggravated by the expression of OSF-2 gene or the production of OSF-2 protein concurrent with the progress of the pathology of heart failure, sufficiently suggesting that a drug containing a substance having the action of inhibiting the expression of OSF-2 gene or inhibiting the production or function of OSF-2 protein as an active ingredient inhibits aggravation of heart failure, which led to the present invention.

[0014] Accordingly, the present invention provides:

[0015] (1) a prophylactic or therapeutic agent for heart failure comprising a substance inhibiting the expression of OSF-2 gene or the production of OSF-2 protein or the function of OSF-2 protein or the function of a target molecule of OSF-2 protein as an active ingredient;

[0016] (2) a prophylactic or therapeutic agent for heart failure comprising a substance inhibiting the expression of OSF-2 gene as an active ingredient;

[0017] (3) a prophylactic or therapeutic agent for heart failure comprising a substance inhibiting the production of OSF-2 protein as an active ingredient;

[0018] (4) the prophylactic or therapeutic agent for heart failure as defined in (1) to (3) above wherein the substance inhibiting the expression of OSF-2 gene or the production of OSF-2 protein is an antisense nucleotide sequence;

[0019] (5) the prophylactic or therapeutic agent for heart failure as defined in (4) above wherein the antisense nucleotide sequence comprises nucleotides complementary to 12 or more contiguous nucleotides in the nucleotide sequence shown as SEQ ID NO: 5, 19, 20 or 21;

[0020] (6) the prophylactic or therapeutic agent for heart failure as defined in (5) above wherein the antisense nucleotide sequence comprises at least one sequence selected from the group consisting of SEQ ID NOs: 12-16;

[0021] (7) the prophylactic or therapeutic agent for heart failure as defined in (1) or (2) above wherein the substance inhibiting the expression of OSF-2 gene is a compound of the following general formula (I):

[0022] wherein R1 represents a hydrogen atom, an optionally branched alkyl group or an aralkyl group in which the alkyl moiety may be branched, R2 represents a hydrogen atom, a halogen atom or an amino group, R3 and R4 independently represent a hydrogen atom or an acyl group or R3 and R4 taken together represent an isopropylidene group, and n represents an integer of 0, 1, 2 or 3, or a biologically acceptable salt thereof;

[0023] (8) the prophylactic or therapeutic agent for heart failure as defined in (7) above wherein the substance inhibiting the expression of OSF-2 gene is a compound of general formula (I) above wherein both R3 and R4 represent a hydrogen atom;

[0024] (9) the prophylactic or therapeutic agent for heart failure as defined in (7) above wherein the substance inhibiting the expression of OSF-2 gene is a compound of general formula (I) above wherein R1, R3 and R4 represent a hydrogen atom, R2 represents a chlorine atom and n is 3;

[0025] (10) the prophylactic or therapeutic agent for heart failure as defined in (7) above wherein the substance inhibiting the expression of OSF-2 gene is a compound of general formula (I) above wherein R1 represents a (2-methylphenyl)methyl group, R3 and R4 represent a hydrogen atom and n is 0;

[0026] (11) the prophylactic or therapeutic agent for heart failure as defined in (1) above comprising a substance inhibiting the function of OSF-2 protein as an active ingredient;

[0027] (12) the prophylactic or therapeutic agent for heart failure as defined in (1) above comprising a substance inhibiting the function of a target molecule of OSF-2 protein as an active ingredient;

[0028] (13) the prophylactic or therapeutic agent for heart failure as defined in (11) or (12) above wherein the substance inhibiting the function of OSF-2 protein or the function of a target molecule of OSF-2 protein is an antibody to OSF-2 protein or the target molecule of OSF-2 protein;

[0029] (14) a method for screening a substance having a prophylactic or therapeutic effect for heart failure comprising contacting a synthesized or genetically engineered substance or a natural substance or a derivative thereof with (1) a cell or an in vitro expression system having an expression regulatory region of OSF-2 gene and OSF-2 gene or a reporter gene or (2) OSF-2 protein or a target molecule of OSF-2 protein to detect the expression level of OSF-2 gene or the reporter gene or the amount of OSF-2 protein or the target molecule of OSF-2 protein;

[0030] (15) the method as defined in (14) above comprising contacting a synthesized or genetically engineered substance or a natural substance or a derivative thereof with a cell having an expression regulatory region of OSF-2 gene and OSF-2 gene to detect the expression level of OSF-2 gene;

[0031] (16) the method as defined in (14) above comprising constructing an expression vector having an expression regulatory region of OSF-2 gene linked upstream and/or downstream of the translation region of a reporter gene, then culturing a suitable host cell transfected with said vector, adding a synthesized or genetically engineered substance or a natural substance or a derivative thereof to the cultured cell and detecting the expression level of the reporter gene or the amount of the reporter protein after a given period;

[0032] (17) the method as defined in (14) above comprising contacting a synthesized or genetically engineered substance or a natural substance or a derivative thereof with OSF-2 protein or a target molecule of OSF-2 protein to detect the amount of the target molecule of OSF-2 protein or OSF-2 protein bound or unbound;

[0033] (18) the method as defined in (17) above comprising immobilizing OSF-2 protein or a target molecule of OSF-2 protein to a support and adding a synthesized or genetically engineered substance or a natural substance or a derivative thereof and the target molecule of OSF-2 protein or OSF-2 protein to the immobilized OSF-2 protein or target molecule of OSF-2 protein to detect the amount of the target molecule of OSF-2 protein or OSF-2 protein bound or unbound;

[0034] (19) a method for diagnosing heart failure comprising collecting a biological tissue and/or a body fluid and determining the expression level of OSF-2 gene in said tissue or determining a variation in OSF-2 gene or said regulatory region;

[0035] (20) a method for diagnosing heart failure comprising collecting a biological tissue and/or a body fluid and assaying OSF-2 protein or said fragment in said body fluid;

[0036] (21) a diagnostic reagent or a diagnostic kit for heart failure comprising a means for determining the expression level of OSF-2 gene or the production level of OSF-2 protein;

[0037] (22) a gene encoding a protein (a) or (b) below:

[0038] (a) a protein comprising the amino acid sequence of SEQ ID NO: 6,

[0039] (b) a protein comprising a variant of the amino acid sequence of SEQ ID NO: 6 in which one or several amino acids are deleted, substituted or added and having OSF-2 protein activity;

[0040] (23) a gene encoding a DNA (a) or (b) below:

[0041] (a) a DNA comprising the nucleotide sequence of SEQ ID NO: 5,

[0042] (b) a DNA hybridizing to the sequence of SEQ ID NO: 5 under stringent conditions and encoding a protein having OSF-2 protein activity;

[0043] (24) a recombinant protein (a) or (b) below:

[0044] (a) a protein comprising the amino acid sequence of SEQ ID NO: 6,

[0045] (b) a protein comprising a variant of the amino acid sequence of SEQ ID NO: 6 in which one or several amino acids are deleted, substituted or added and having OSF-2 protein activity;

[0046] (25) a non-human transgenic animal overexpressing OSF-2 gene and suitable for use as a pathologic model of heart failure;

[0047] (26) a method for evaluating or screening a substance capable of being an active ingredient of a prophylactic or therapeutic agent for heart failure using the non-human transgenic animal as defined in (25) above;

[0048] (27) a substance obtained by the method as defined in (14) to (18) or (26) above;

[0049] (28) a prophylactic or therapeutic agent for heart failure comprising the substance as defined in (27) above as an active ingredient;

[0050] (29) a method for treating heart failure comprising administering the substance as defined in (1) to (13) or (27) above;

[0051] (30) the method for treating heart failure as defined in (29) above comprising introducing an antisense nucleotide sequence of OSF-2 gene directly or incorporated into a vector (e.g. adenovirus-derived vector) or a liposome suitable for gene therapy;

[0052] (31) a use of the substance as defined in (1) to (13) or (27) above for the preparation of a prophylactic or therapeutic agent for heart failure.

BRIEF DESCRIPTION OF THE FIGURES

[0053]
FIG. 1 shows expression levels of OSF-2 gene standardized by expression levels of GAPDH gene in various animal models.

[0054]
FIG. 2 shows inhibitory activities against OSF-2 protein production of the antisense nucleotide sequences of SEQ ID NO: 12 to 16. C means a control.

[0055]
FIG. 3 shows inhibitory activities against OSF-2 protein production of an antisense nucleotide sequence (SEQ ID NO: 12), a sense nucleotide sequence (SEQ ID NO: 17) and a scramble nucleotide sequence (SEQ ID NO: 18).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0056] The following substances (1) to (3) can be used as active ingredients of prophylactic or therapeutic agents for heart failure in the present invention.

[0057] (1) Substances Inhibiting the Expression of OSF-2 Gene

[0058] Substances inhibiting the expression of OSF-2 gene may be any of synthesized or genetically engineered compounds or natural compounds or derivatives thereof, including substances acting on a promoter or enhancer region of OSF-2 gene to inhibit the transcription of OSF-2 gene into mRNA (e.g., antisense nucleotides including DNA, RNA, phosphorothioate-type or other modified nucleotides and PNA (protein nucleic acid)), or substances having similar actions via a certain element in cells (such as a transcription factor) (e.g., substances binding to a transcription factor or a co-activator to inhibit binding to DNA or another transcription factors or co-activators).

[0059] The term “nucleotides” in reference to antisense nucleotides here means to include nucleotides produced from a naturally occurring bases and sugar moiety linked via proper phosphodiester bonds and analogs thereof. Thus, a first group included in this term encompasses naturally occurring species or synthetic species produced from naturally occurring subunits or homologs thereof. Subunits here refer to base-sugar combinations linked to adjacent subunits via phosphodiester bond or other bonds. A second group of nucleotides encompasses analogs of the first group, which mean residues having nucleotide-like functions but having a non-naturally occurring moiety. These include nucleotides chemically modified at the phosphate group, sugar moiety or 3′ or 5′ end to increase stability. Examples are phosphorothioate and methylphosphonate obtained by substituting a sulfur atom and —CH3, respectively, for one of the oxygen atoms of the phosphodiester group between nucleotides. Nucleotide analogs containing purine and pyrimidine in the form of modified bases, i.e. other than normally found in nature can also be used.

[0060] Preferred antisense nucleotides for use in the present invention are nucleotides complementary to 12 or more contiguous nucleotides, preferably 16 or more contiguous nucleotides, more preferably 18 or more contiguous nucleotides in the nucleotide sequence shown as SEQ ID NO: 5, 19, 20 or 21. Especially preferred antisense nucleotides have at least one sequence selected from the group consisting of SEQ ID NOs: 12-16.

[0061] In the present invention, peptide nucleic acids (Bioconjug. Chem., 4 373-378, 1994) can also be used in place of antisense nucleotides.

[0062] Specific examples of compounds inhibiting the expression of OSF-2 gene include compounds of general formula (I) below or biologically acceptable salts thereof.

[0063] In the formula above, R1 represents a hydrogen atom, an optionally branched alkyl group or an aralkyl group in which the alkyl moiety may be branched. Examples of the optionally branched alkyl group include methyl, ethyl, isopropyl, isobutyl and tert-butyl groups. In the case of the aralkyl group in which the alkyl moiety may be branched, the aryl moiety may be substituted by a lower alkyl group such as methyl, ethyl or propyl, a lower alkoxy group such as methoxy or ethoxy, a halogen atom, nitro, cyano, carboxyl, alkoxycarbonyl or the like. Representative examples include benzyl, (2-methylphenyl)methyl, (3-methylphenyl)methyl, (4methylphenyl)methyl, (2-chlorophenyl)methyl, (2-ethylphenyl)methyl, (2-methoxyphenyl)methyl, (2-methoxycarbonylphenyl)methyl, 2-phenethyl, (1-naphthyl)methyl, (2-naphthyl)methyl and 2-(2-naphthyl)ethyl groups. Among them, preferred examples for R1 include a hydrogen atom and aralkyl groups in which the alkyl moiety may be branched, among which a hydrogen atom and a (2-methylphenyl)methyl group are especially preferred.

[0064] R2 represents a hydrogen atom, a halogen atom or an amino group. Preferred examples for R2 include a hydrogen atom and a chlorine atom.

[0065] R3 and R4 independently represent a hydrogen atom or an acyl group or R3 and R4 jointly represent an isopropylidene group. Examples of acyl groups include lower alkanoyl groups such as acetyl and propionyl.

[0066] n represents 0, 1, 2 or 3, among which 0 and 3 are especially preferred. When n is 1, 2 or 3, one or more hydrogen atoms in the phosphonate moiety may form a salt with an alkali metal or an alkali earth metal such as sodium, potassium, calcium or magnesium or an organic amine.

[0067] (2) Substances Inhibiting the Production of OSF-2 Protein

[0068] Substances inhibiting the production of OSF-2 protein may be any of synthesized or genetically engineered compounds or natural compounds or derivatives thereof, including substances inhibiting the translation of OSF-2 mRNA into OSF-2 protein by an antisense nucleotide sequence of OSF-2 gene. The term “nucleotide” in reference to antisense nucleotide here is as defined in (1) above. Antisense nucleotides include RNA, DNA, phosphorothioate-type or other modified nucleotides or PNA (protein nucleic acid) and can be designed to target any of the structural gene region, 3′-untranslated region, 5′-untranslated region or intron/exon junction of OSF-2 gene. Antisense strands can be introduced into a target tissue directly or by introducing a vector designed to be transcribed into antisense RNA.

[0069] Ribozymes recognizing a specific structure of OSF-2 mRNA to cleave it can also be used. Ribozymes are nucleic acid molecules having an enzymatic activity capable of cleaving other RNA molecules in a manner specific to a target nucleotide sequence and can be formed, for example, in hammerhead or hairpin motifs, (Nature, 324, 429, 1986; Ann. Rep. Med. Chem., 30 285-294, 1995;J. Med. Chem., 38, 2023-2037, 1995). Ribozymes may be introduced into a target tissue directly or in the form of a complex with a lipid or a liposome. Alternatively, a DNA or RNA vector expressing a ribozyme can be introduced into a target tissue.

[0070] (3) Substances Inhibiting the Function of OSF-2 Protein or Substances Inhibiting the Function of a Target Molecule of OSF-2 Protein

[0071] In the present invention, substances inhibiting the function of OSF-2 protein or substances inhibiting the function of a target molecule of OSF-2 protein can be used in prophylactic or therapeutic agents for heart failure. The target molecule of OSF-2 protein means a molecule whose structure or activity is influenced by OSF-2 protein, including, but not limited to, substrates, binding partners and receptors.

[0072] Substances inhibiting the function of OSF-2 protein or substances inhibiting the function of a target molecule of OSF-2 protein may be any of synthesized or genetically engineered compounds or natural compounds or derivatives thereof, including substances inhibiting binding of OSF-2 protein to a target molecule (e.g. receptor) of OSF-2 protein on which OSF-2 protein acts, or substances inhibiting intracellular signal transduction to inhibit the activity of OSF-2 protein. Examples are antibodies against OSF-2 protein or antibodies against a target molecule of OSF-2 protein. The antibodies may be polyclonal or monoclonal. These antibodies can be prepared by, for example, purifying the protein from cultures of expression cells or recombinant host and immunizing a rabbit or the like with the purified protein together with a suitable adjuvant to obtain an antibody fraction from the serum according to standard methods. Alternatively, monoclonal antibodies can be prepared using mice or rats, or humanized antibodies or single-strand antibodies can be prepared using genetic engineering techniques or transgenic animals, although the present invention is not limited to these specific methods. The substances also include proteases specifically degrading OSF-2 protein or a target molecule of OSF-2 protein, inactivated OSF-2 protein (including variants) or decoys of OSF-2 target molecules and soluble receptor molecules.

[0073] When the substances (1) to (3) above are peptides, they also include peptide analogs having an enzyme-acting site modified to make drugs of the present invention unsusceptible or less susceptible to in vivo degradation by peptidases or proteases after administration to a subject. Said analogs include peptide analogs wherein one or more peptide bonds at the enzyme-acting site are replaced by another covalent bond or peptide analogs wherein one or more amino acids at the enzyme-acting site are D-amino acids.

[0074] Pharmaceutical Preparations

[0075] Pharmaceutical preparations containing the substances as described above as active ingredients are prepared using carriers or excipients or other additives used for standard formulation.

[0076] Active ingredients of pharmaceutical compositions of the present invention may be free acid or base, or pharmaceutically acceptable salts thereof Suitable salts include salts with inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid or salts with organic acids such as formic acid, acetic acid, butyric acid, succinic acid and citric acid. Salts with metals such as sodium, potassium, lithium and calcium or salts with organic bases are also suitable.

[0077] Preferably, active ingredients are mixed with known pharmacologically acceptable carriers, excipients, diluents or the like and administered in a pharmaceutically conventional manner such as oral administration or parenteral administration including intravenous, intramuscular or subcutaneous administration. Pharmaceutical compositions of the present invention can be prepared by, for example, appropriately mixing an active ingredient with physiologically acceptable carriers, flavoring agents, excipients, stabilizers, diluents, emulsifiers, solubilizing agents, dispersing agents, syrups or the like and can be used as tablets, powders, granules, solutions, etc. Tablets can contain additives including, for example, binders such as gelatin and lubricants such as cornstarch, or can be coated with sugar or a gastric or enteric film. Capsules can be prepared by further including liquid carriers in said compositions. Sterile compositions for injection can also be prepared by applying conventional formulations. Aqueous solutions for injection include isotonic solutions containing glucose or the like and can be combined with suitable solubilizers such as polyethylene glycol. They may also contain buffers, stabilizers, preservatives, antioxidants, soothing agents and the like. When active ingredients are susceptible to degradation in the gastrointestinal tract via oral administration, they can be orally administered as formulations less susceptible to degradation in the gastrointestinal tract such as microcapsules enclosing active ingredients in liposomes, for example. They can also be adsorbed via non-gastrointestinal mucosa such as rectal, nasal or sublingual administration. In this case, they can be administered in the form of suppositories, nasal sprays or sublingual tablets.

[0078] For use in gene therapy, antisense nucleotides or the like can be integrated into known vectors suitable for gene therapy such as adenoviruses.

[0079] When pharmaceutical compositions of the present invention are therapeutically used, therapeutically effective doses are determined for each case depending on the age and the weight of the subject, the severity of the disease and the route of administration and other factors. Typically, the oral dose is about 0.1-1000 mg/adult/day, which may be administered once or divided into several subdoses. For continuous intravenous administration, the dose can range from 0.01 μg/kg/min to 1.0 μg/kg/min, preferably from 0.025 μg/kg/min to 0.1 μg/kg/min.

[0080] Screening Methods

[0081] Substances that can be used as active ingredients of prophylactic or therapeutic agents of the present invention can be screened as follows, for example.

[0082] OSF-2 gene or OSF-2 protein or derivatives thereof used for screening substances inhibiting the expression of OSF-2 gene or substances inhibiting the production of OSF-2 protein may be derived from any sources including mammals such as human, mouse, rat, rabbit, pig, dog, monkey and guinea pig. That is, they include known genes or proteins in addition to the newly found rat gene (SEQ ID NO: 5) or the protein encoded thereby (SEQ ID NO: 6). OSF-2 gene and OSF-2 protein of the present invention include various known splice variants of OSF-2 gene and proteins translated therefrom since various splice variants of OSF-2 gene are known. For example, murine OSF-2 genes and OSF-2 proteins include those shown as SEQ ID NO: 19 and human OSF-2 genes and OSF-2 proteins include those shown as SEQ ID NOs: 20 (from placenta) and 21 (from primary tumor). Partial sequences of OSF-2 gene can also be used alone or as a chimeric gene with another gene. Similarly, partial sequences of OSF-2 protein can be used alone or fused with another peptide.

[0083] Among them, human genes or proteins are preferably used for studies/developments of prophylactic or therapeutic agents for human. Those derived from animals such as mouse and rat are preferably used for studies/developments using animal models, i.e. non-human transgenic animals having heart failure condition due to forced expression of OSF-2 gene.

[0084] Substances inhibiting the expression of OSF-2 gene or substances inhibiting the production of OSF-2 protein are generally screened by methods using a reporter gene. Suitable reporter genes include, for example, chloramphenicol acetyl transferase (CAT), β-galactosidase (β-Gal) and luciferase. Substances inhibiting the expression of OSF-2 gene can be screened by, for example, constructing an expression vector having an expression regulatory region (promoter, enhancer or the like region) of OSF-2 gene linked upstream and/or downstream of the coding region of a reporter gene, transfecting said vector into a suitable culture cell, adding a test substance to the culture cell (said substance may be any of synthesized or genetically engineered compounds or natural compounds or derivatives thereof) and determining the expression level of the reporter gene or the amount of the reporter protein after a given period. The expression regulatory region of OSF-2 gene (promoter, enhancer or the like region) can be obtained from commercially available genomic libraries by plaque hybridization using a fragment of OSF-2 cDNA as a probe. In the examples below, for example, compounds inhibiting the expression of OSF-2 gene were found by introducing a “reporter vector” having a promoter region of OSF-2 gene linked upstream of a luciferase gene into COS-1 cells and assaying luciferase activity after adding a candidate compound. Substances of the present invention also include decoys, i.e. decoy-type nucleic acid drugs against transcription factors acting on OSF-2 gene (Science. 250, 997-1000, 1990) or the like. The amount of the reporter protein can be determined as enzymatic activity or the expression level of the protein using antibodies or the like.

[0085] Antisense nucleotides or ribozymes or the like inhibiting the production of OSF-2 protein can be screened by introducing the antisense nucleotides or ribozymes into culture cells expressing OSF-2 protein by e.g. electroporation or liposome techniques and determining the expression level of OSF-2 protein. In the examples below, for example, antisense nucleotides inhibiting the expression of OSF-2 protein were found by introducing a series of antisense nucleotides targeted on the initiation codon of OSF-2 into COS-1 cells overexpressing OSF-2 protein. Any antisense nucleotides having such an action may be suitable such as those inhibiting transcription, mRNA splicing or passage of mRNA through nuclear membrane. Similar methods can be used for screening ribozymes. Suitable culture cells include cells transfected with OSF-2 gene as well as any cells originally expressing OSF-2 gene such as MC3T3-E1 cells (Biochem.J. 294, 271-278, 1993) and the like.

[0086] Substances inhibiting the function of OSF-2 protein or substances inhibiting the function of a target molecule of OSF-2 protein can be screened by, for example, immobilizing either the target molecule of OSF-2 protein or OSF-2 protein to a plate or the like, and then adding a test substance (said substance may be any of synthesized compounds or natural compounds or derivatives thereof) and OSF-2 protein or a target molecule thereof, and determining the amount of OSF-2 protein or the target molecule of OSF-2 protein bound or unbound by ELISA, RIA, fluorescence labeling or the like. They can also be screened by using cells expressing a target molecule of OSF-2 with labeled OSF-2 and a test drug followed by a suitable washing treatment after a given period and then determining the number of labeled cells or the extent of labeling by FACS, absorbance, color development or other means. Alternatively, they can also be screened on the basis of the action shown by OSF-2 (e.g. adhesion activity) by adding a test substance (said substance may be any of synthesized compounds or natural compounds or derivatives thereof) into a culture medium of culture cells and determining the strength of the action shown by OSF-2.

[0087] Diagnostic Methods. Diagnostic Agents and Diagnostic Kits

[0088] OSF-2 gene was shown by the inventors of the present application to increase the expression level with aggravation of heart failure. The extent of aggravation of heart failure can be diagnosed by determining the expression level of OSF-2 gene using a biopsy sample of a patient with heart failure. For example, the expression level of OSF-2 gene can be determined by isolating total RNA from a biopsy sample of a patient using ISOGEN (Nippon Gene) and treating it with DNase, then synthesizing cDNA, amplifying OSF-2 gene by PCR using suitable primers and determining the intensity of the band corresponding to OSF-2 by gel electrophoresis. The expression of OSF-2 gene can also be determined by any other techniques for quantitatively measuring RNA or DNA such as the method described in Example 3, Northern hybridization or cDNA array techniques.

[0089] As OSF-2 gene was shown by the present invention to be an aggravating factor of heart failure, it can be readily predicted that individuals having some variation in OSF-2 gene or a regulatory region thereof tend to be susceptible to heart failure or aggravation in heart failure if the function of OSF-2 protein is enhanced or the gene expression level is increased by the presence of such variation. Thus, risk factors can be diagnosed by testing these variations in the gene. Variations in the gene can be detected by isolating DNA from a blood sample of a patient according to standard methods, determining the nucleotide sequence according to the method described in Examples 1-5 and comparing it with the normal sequence. Once the relation between a variation and heart failure has been clarified, the DNA chip or SSCP technique can be applied to specifically detect such a variation.

[0090] As OSF-2 is known to be a secretory protein, it is readily predicted that an increase in gene expression is accompanied by an increase in OSF-2 protein levels in the heart and blood. Thus, the extent of aggravation of heart failure can be known by assaying OSF-2 protein levels in the blood. Suitable assay methods include ELISA or RIA using antibodies against OSF-2, or HPLC or mass spectrometric assays. OSF-2 protein here may not be in a total form but may be fractionated so far as it can be assayed.

[0091] The present invention also include diagnostic agents or diagnostic kits for heart failure comprising a means for deter ng the expression level of OSF-2 gene or the production level of OSF-2 protein using the assay means as described above.

[0092] Non-human Transgenic Animals Transfected with OSF-2 Gene

[0093] Non-human host animals for creating non-human transgenic animals having heart failure condition due to forced overexpression of OSF-2 gene in the present invention include small animals such as mouse, rat and rabbit as well as large animals such as dog, pig, sheep and cattle and any other animals expressing OSF-2 gene and showing the function or physiological action of OSF-2 protein. Suitable promoters for expressing OSF-2 gene include constitutively expressing promoters (CMV promoters, SV40 early promoters, etc.) as well as tissue-specific promoters (αXMHC promoters,α-actin promoters, etc.), inducibly expressing promoters (Cre-loxP system, tetracycline inducible system, ecdysone inducible system, etc.) and any other systems capable of inducing gene expression.

[0094] The present invention provides transgenic animals inducibly and heart tissue-specifically expressing OSF-2 gene. Suitable inducible expression systems include, for example, ecdysone inducible system (Proc Natl. Acad. Sci. U.S.A., 93 3346-3351, 1996; Nature, 366 476-479, 1993; Cell, 71, 63-72, 1992). This inducible expression system is designed to constitutively express ecdysone receptor and retinoid X receptor (RXR receptor) so that a receptor heterodimer consisting of both receptors binds to an ecdysone-responsive region in the presence of ecdysone to induce the expression of a target gene downstream thereof. For example, an “induction transgenic animal” expressing ecdysone receptor and RXR receptor and an “expression transgenic animal” expressing an ecdysone-responsive region and a target gene can be separately prepared and crossed to prepare a double transgenic animal. The target gene can be induced by administering ecdysone to this double transgenic animal.

[0095] Initially, a transgenic animal characterized by expressing OSF-2 protein is prepared by a standard method, which is an animal obtained by ontogenesis of totipotent cells transfected with a recombinant gene for preparing a transgenic animal obtained by linking OSF-2 gene downstream of an ecdysone responsive region (transgenic animal for expression) and progeny thereof.

[0096] On the other hand, a transgenic animal characterized by inducibly expressing an ecdysone receptor protein specifically in the heart tissue and an RXR protein systemically is prepared, which is an animal obtained by ontogenesis of totipotent cells transfected with a recombinant gene for preparing a transgenic animal having both an expression unit having an ecdysone receptor gene inked downstream of a heart tissue-specifically expressing promoter and an expression unit having RXR gene linked downstream of a non-tissue specific promoter and progeny thereof (transgenic animal for induction).

[0097] The totipotent cells here mean cells capable of potentially differentiating into any cells. In the case of mouse, for example, totipotent cells may be fertilized eggs and early embryos as well as culture cells such as pluripotent ES cells. DNA fragments can be introduced into culture cells by electrostatic pulsing, liposome, calcium phosphate and other techniques. Physical injection of DNA solutions into fertilized eggs (microinjection) is specially preferred.

[0098] Recombinant genes used in the processes for preparing a transgenic animal according to the present invention are desirably inserted during the embryogenic stage. Cells transfected with DNA are transplanted into an surrogate mother animal, which is fed and allowed to give birth to an intended offspring transgenic animal transfected with a desired gene (founder transgenic animal). The presence of the transgene can be confirmed by PCR or Southern blotting of somatic DNA isolated from a section of a part of the body of the animal (e.g. tail end).

[0099] Moreover, progeny animals of transgenic animals of the present invention can be prepared by further including the steps of crossing each founder transgenic animal and a normal animal to give F1 animals (progeny animals) and crossing transgenic animals expressing the trait among said F1 animals each other or with normal animals to give homozygous or heterozygous F2 animals (progeny animals). The inventors in fact have succeeded in preparing these transgenic animals.

[0100] Double transgenic animals can be obtained by crossing a transgenic animal for expression and a transgenic animal for induction and confirming the presence of both genes, and then transgenic animals inducibly and heart tissue-specifically expressing OSF-2 gene can be obtained by administering ecdysone to said double transgenic animals.

[0101] Transgenic animals of the present invention can be used for pathological studies and drug screening as models of diseases in which OSF-2 gene is involved (e.g. heart failure models).

[0102] Moreover, substances as active ingredients of prophylactic or therapeutic agents for diseases in which OSF-2 gene is involved (e.g. heart failure) can be evaluated or screened by administering a candidate substance to a transgenic animal of the present invention and determining the expression level of OSF-2 gene, the production of OSF-2 protein or changes in cardiac function, etc. Thus, the present invention also includes methods for evaluating or screening substances as active ingredients of prophylactic or therapeutic agents for diseases in which OSF-2 gene is involved using transgenic animals of the present invention.

[0103] Therapeutic agents for heart failure provided by the present invention exhibit their activity on the specific target and have efficacy based on a different mechanism from conventional ones for mild to severe heart failure in which OSF-2 gene or protein is involved. Screening methods of the present invention lead to the development of therapeutic agents for all diseases including heart failure in which OSF-2 gene or protein is involved. According to diagnostic methods of the present invention, the extent of aggravation or the risk of the onset of heart failure can be predicted, which helps improvements of lifestyle or treatments. Moreover, transgenic animals of the present invention can be used for pathological studies or drug screening as models of diseases in which OSF-2 gene is involved.

[0104] The following examples further illustrate the present invention. These examples are given for illustrative purposes, but are not construed as limiting the scope of the invention.

EXAMPLES

Example 1

Search for OSF-2 by Subtraction Method

[0105] 1-1 Preparation of Pathologic Model Rats of Heart Failure and Collection of Left Ventricular Samples

[0106] Male Dahl salt-sensitive rats (Dahl-S) (SHIMIZU LABORATORY SUPPLIES) were raised on an 8% high salt diet from 6 weeks of age, and the left ventricle was collected from three animals each at cardiac hypertrophy stage (11 weeks of age) and heart failure stage (14 weeks of age).

[0107] 1-2 Preparation of mRNA

[0108] Total RNA was prepared from about 500 mg of said left ventricle using ISOGEN (Nippon Gene) as instructed by the manufacturer. Then, mRNA was purified from about 400 μg of the combined total RNA from three animals each at cardiac hypertrophy stage and heart failure stage using Fast Track 2.0 Kit (Invitrogen) as instructed by the manufacturer to recover about 3 μg of mRNA at each stage.

[0109] 1-3 cDNA Subtraction

[0110] cDNA subtraction was performed using PCR-Select cDNA subtraction kit (Clontech) as instructed by the manufacturer. That is, cDNA was synthesized from 2 μg of each mRNA obtained in 1-2 above and digested with restriction enzyme RsaI. Then, subtractive hybridization was performed using the cDNA synthesized from the left ventricle of animals at 14 weeks of age as tester cDNA and the cDNA synthesized from the animals at 11 weeks of age as driver cDNA after the 2 adapters included in the kit had been separately linked to the tester cDNA. Then, a cDNA fragment with altered expression level was specifically amplified by PCR using primers complementary to the adapters to give amplification product 1.

[0111] A similar subtraction operation was performed using the cDNA synthesized from the left ventricle of animals at 11 weeks of age as tester cDNA and the cDNA synthesized from the left ventricle of animals at 14 weeks of age as driver cDNA to give amplification product 2.

[0112] 1-4 Dot Blot Screening

[0113] A. Preparation of Dot Blots

[0114] Amplification product 1 was TA cloned into PCR II vector (Invitrogen) to select clones having the insert fragment. One μl each of the PCR reaction solution in which the insert fragment of each clone had been amplified was heat-treated, and then dot-blotted on 2 nylon membrane filters (Boehringer) and fixed with UV crosslinker (Stratagene).

[0115] B. Preparation of cDNA Probes

[0116] Amplification product 1 was digested with restriction enzymes RsaI,EaeI and SmaI to remove the adapters and subjected to random prime labeling with DTG-dUTP using DIG High Prime DNA labeling/detection kit II (Boehringer) as instructed by the manufacturer to prepare cDNA probe 1. Similarly, cDNA probe 2 was prepared from amplification product 2.

[0117] C. Screening

[0118] One of the dot blot membranes prepared in A above was hybridized with cDNA probe 1 and the other with cDNA probe 2 (under the conditions of hybridization at 42° C. overnight in DIG Easy Hyb solution as instructed by Boehringer for DIG High Prime DNA labeling/detection kit II and washing twice with 2 x SSC, 0.1% SDS at room temperature for 5 minutes and twice with 0.1 x SSC, 0.1% SDS at 68° C. for 15 minutes) and reacted with alkaline phosphatase-labeled DIG antibodies in the blocking buffer included in the kit, and then CSPD ready-to use was added to develop chemiluminescence and X-ray film was exposed. Clones showing a stronger signal with cDNA probe 1 than cDNA probe 2 were selected as positive clones and sequenced.

[0119] 1-5 Sequencing

[0120] The nucleotide sequences were determined by analysis on an automatic DNA sequencer model 373A (PE Applied Biosystems) using THERMO SequenaseTM II dye terminator cycle sequencing kit (Amersham Pharmacia). The resulted gene sequences were compared with GenBank databanks to reveal that one of the clones (SF014) was a gene having a 86% homology to mouse OSF-2 (GenBank Accession No. D13664).

Example 2

Cloning of Rat OSF-2 cDNA

[0121] Rat OSF-2 cDNA was isolated by screening 10 phage subpools of about 4000 clones (a total of about 40,000 clones) prepared from a rat aorta cDNA library (Clontech) inserted into λgt1 vector by PCR using primer (1) 5′-GTTCATTGAAGGTGGCGATGGTC-3′ (SEQ ID NO: 1) and primer (2) 5′-GAGATAAAATCCCTGCATGGTCCT-3′ (SEQ ID NO: 2) designed on the basis of the nucleotide sequence of SF014 to give 3 positive subpools. One of the subpools was screened by hybridization using the fragment amplified by the above mentioned PCR as a probe labeled with alkaline phosphatase using AlkPhos Direct™ (Amersham Pharmacia) to give one positive clone rat OSF-2#1. The insert fragment was integrated into the EcoRI site of pBluescript II (Stratagene) and the total nucleotide sequence was determined according to the method of Example 1-5.

[0122] The resulting clone had a length of about 3 kb corresponding to the nucleotide sequence from 292 to the 3′ end of mouse OSF-2 (GenBank Accession No. D13664), suggesting that it was a 5′-truncated clone. Thus, SMART™ RACE cDNA Amplification Kit (Clontech) was used as instructed by the manufacturer to perform 5′-RACE reaction using rat aorta cDNA as a template and said primer (2) 5′-GAGATAAAATCCCTGCATGGTCCT-3′ (SEQ ID NO: 2) and primer (3) 5′-CACGGTCGATGACATGGACAACACC-3′ (SEQ ID NO: 3) designed on the basis of the nucleotide sequence of rat OSF-2#1. The resulting PCR product was TA cloned into PCR II vector of Invitrogen to give rat OSF-2 5RACE #1. The nucleotide sequence was determined according to the method of Example 1-5.

[0123] The results showed that rat OSF-2 5RACE #1 was a clone longer by about 300 bp than the initially obtained rat OSF-2#1 in the 5′ direction with the 5′ end being longer by 15 bp than the 5′ end of mouse OSF-2 (GenBank Accession No. D13664). Ten phage subpools of about 40,000 clones (a total of about 400,000 clones) prepared from said rat aorta cDNA library were screened by PCR using primer (4) 5′-ACGGAGCTCAGGGCTGAAGATG-3′ (SEQ ID NO: 4) designed on the basis of the nucleotide sequence of rat OSF-2 5RACE #1 and said primer (3) 5′-CACGGTCGATGACATGGACAACACC-3′ (SEQ ID NO: 3) to give 2 positive subpools. One of the subpools was screened by hybridization using the fragment amplified by the above mentioned PCR as a probe to give one positive clone designated as rat OSF-2#2. The insert fragment was integrated into the EcoRI site of pBluescript II (Stratagene) and the nucleotide sequence was determined according to the method of Example 1-5.

[0124] The resulting clone had a length of about 2.6 kb with the 5′ end being the same as that of the clone obtained with 5′-RACE and the 3′ end corresponding to up to nucleotide 2410 of mouse OSF-2 (GenBank Accession No. D13664). The nucleotide sequence of rat OSF-2 5RACE #1 previously obtained was exactly the same as the nucleotide sequence of the relevant region of rat OSF-2#2. The full length of rat OSF-2 cDNA was completed by rat OSF-2#1 and rat OSF-2#2. The nucleotide sequence of this full-length cDNA and the ammo acid sequence translated from this nucleotide sequence are shown as SEQ ID NOs: 5 and 6.

Example 3

Analysis of the Expression of OSF-2 gene in various heart Failure model Rats

[0125] OSF-2 gene was selected by subtraction as a gene expressed at a higher level during heart failure stage in Dahl rats. This gene was tested for the extent to which it actually shows expression changes and whether or not it shows similar changes in various heart failure models other than Dahl rats.

[0126] 3-1 Preparation of Model Rats and collection of samples

[0127] A. Dahl Heart Failure Model Rats

[0128] Male Dahl salt-sensitive rats (Dahl-S) (SHIMIZU LABORATORY SUPPLIES) were raised on an 8% high salt diet from 6 weeks of age, and the left ventricle was collected at cardiac hypertrophy stage (11 weeks of age) and heart failure stage (14 weeks of age). Dahl-S rats at 10 weeks of age raised on a normal diet were used as control.

[0129] B. Abdominal Aortostenotic Rats (Pressure Overload Model)

[0130] B-1. Procedure for Preparing a Pressure Overload Induced Cardiac Hypertrophy Rat Model

[0131] Sprague-Dawley strain male rats at 9 weeks of age were used for experiments. After the rats were fixed in a prone position and abdominally incised under anesthesia by intraperitoneal administration of sodium pentobarbital (40 mg/kg), the abdominal aorta was exposed and dissected between the right and left renal arteries. A 21G needle was placed along the aorta and ligated with a silk suture together with the aorta between the right and left renal arteries, and then the needle was pulled out to form aortostenosis. In this model, the systolic blood pressure is raised by such abdominal aortostenosis, thus increasing the afterload of the heart to induce left ventricular hypertrophy.

[0132] B-2. Collection of samples

[0133] The systolic blood pressures at 3 and 17 months after the operation showed higher values than normal, i.e. 232 mmHg and 188 mmHg, respectively, due to arteriostenosis. At month 3, a significant increase in heart weight/body weight ratio was observed and the fractional shortening (FS) indicative of heart function decreased to 26% in rats at month 17 from 52% at month 3. Thus, the left ventricle was collected at 3 and 17 months after stenosis formation as samples of compensatory hypertrophy stage and uncompensated heart failure stage, respectively. Rats at 10 weeks of age were used as control.

[0134] C. Abdominal Arteriovenous Shunt Rats (Volume Overload Model)

[0135] C-1. Procedure for Preparing a Volume Overload Induced Cardiac Hypertrophy Rat Model

[0136] Sprague-Dawley strain male rats at 9 weeks of age were used for experiments. After the rats were fixed in a prone position and abdominally incised under anesthesia by intraperitoneal administration of sodium pentobarbital (40 mg/kg), the abdominal aorta and cava were exposed and the bloodstream was stopped by clamping at the aortic bifurcations to the renal artery and the femoral artery. An 18 G needle was inserted into the aorta at the clamped sites to penetrate into the cava, thereby forming an arteriovenous shunt. The needle was pulled out and the wound in the aorta was closed with a surgical adhesive and the clamps were removed. After confirming that arterial blood flows into the vein in the shunt, the abdomen was closed. In this model, the formation of such an abdominal arteriovenous shunt induces an increase in venous pressure, and therefore an increase in cardiac preload to impose overload successively on the right atrium, right ventricle, left atrium and left ventricle, leading to hypertrophy. Moreover, low compliance in the venous system causes blood retention to induce pulmonary congestion.

[0137] C-2. Collection of Samples

[0138] Heart function was determined by echocardiography at 3 and 11 months after the operation, and then the animals were dissected to test the heart weight and autopsy findings. Rats at 11 months as compared with 3 months after the operation showed decreased hematocrit values and pulmonary edema in every case, suggesting advanced volume overload. The right heart system showed an increase in heart weight/body weight ratio or lung weight/body weight ratio, suggesting edema in the region from the right ventricle to the lung. The FS decreased from 57% to 31%. Therefore, the left ventricle was collected at 3 and 11 months after shunting as samples of compensatory stage and uncompensated heart failure stage, respectively. Rats at 10 weeks of age were used as control.

[0139] D. Spontaneously Hypertensive Rats (Pressure Overload Model)

[0140] SHR rats known as spontaneously hypertensive rats were raised and measured for blood pressure and echocardiogram over time. SHR at 3 months of age showed higher blood pressure and heart weight/body weight ratio than normal and suffered from cardiac hypertrophy due to hypertension. Animals at 19 months of age had appearances such as piloerection and squatting as well as lowered FS from 56% to 32% and lowered systolic blood pressure, and suffered from heart failure. Symptoms such as pleural fluid and edema were also found. The left ventricle was collected by dissection at each stage.

[0141] 3-2 Analysis of Gene Expression

[0142] Gene expression was analyzed by a real-time PCR assay system using ABI PRISM 7700 (PE Applied Biosystems).

[0143] Total RNA was prepared from left ventricle of each model using ISOGEN (Nippon Gene) as instructed by the manufacturer and treated with DNase. TaqMan® Reverse Transcription Reagents (PE Applied Biosystems) were used to synthesize cDNA from 1 μg each of the total RNA treated with DNase in 50 μl of the reaction solution. The primers for detecting OSF-2 and the TaqMan probe used were (5) 5′-TGCAAAAAGAGGTCTCCAAGGT-3′ (SEQ ID NO: 7), (6) 5′-AGGTGTGTCTCCCTGAAGCAGT-3′ (SEQ ID NO: 8), and (7) 5′-FAM ACAAAGTTCATTGAAGGTGGCGATGGTC TAMRA-3′ (SEQ ID NO: 9) designed on the basis of the nucleotide sequence of rat OSF-2 cDNA using a primer design software, ABI PRISM Primer Express. GAPDH used as an internal standard was detected with TaqMan® Rodent GAPDH Control Reagent (PE Applied Biosystems). The calibration curve for OSF-2 was prepared by serial dilution using SF014 described in Example 1 as a control plasmid, and the caliblation curve for GAPDH was prepared by serial dilution using a PCR product obtained by amplifying a partial sequence of rat GAPDH as a control plasmid after TA cloning into PCR II vector (1Invitrogen) to confirm the nucleotide sequence.

[0144] Real-time PCR assay reaction was performed with 0.4-0.8 μl of said cDNA as a template in 40 μl of the reaction solution using TaqMan® Universal PCR Master Mix (PE Applied Biosystems) as instructed by the manufacturer. The analytic results were standardized as the amount of GAPDH used as an internal standard and shown in FIG. 1. The results showed that the expression of OSF-2 increased with the progress of the pathology of heart failure in all the models.

Example 4

Construction of an Myc-His-rOSF-2 fused protein expression vector

[0145] An expression vector having an Myc epitope and 6 histidine tags at the carboxyl terminus of the protein translated from the coding region of rat OSF-2 gene and having a CMV promoter was prepared.

[0146] Initially, a fragment of about 500 bp obtained by digesting rat OSF-2 5RACE #1 obtained in Example 2 with restriction enzymes EcoRI and HindIII and a fragment of about 2780 bp obtained by digesting rat OSF-2#1 obtained in Example 2 with restriction enzymes HindIII and HpaI were ligated to a vector fragment obtained by digesting pTracer-CMV2 vector (Invitrogen) with restriction enzymes EcoRI and EcoRV using a ligation kit (TAKARA SHUZO) to give a plasmid designated as pTracer-CMV2/rOSF-2. Thus prepared pTracer-CMV2/rOSF-2 was digested with restriction enzymes EcoRI and SmaI to give a fragment of about 2330 bp containing the coding region of rat OSF-2 gene. Separately, PCR was performed using rat OSF-2#1 obtained in Example 2 as a template and primer (8) 5′-GACCCGGGAAGAACGCATCATC-3′ (SEQ ID NO: 10) designed on the basis of the sequence of the template and primer (9) 5′-TGGGTGACCCTGAGAACGGCCTTCTCTTGATC-3′ (SEQ ID NO: 11) designed to insert a BstEII site immediately before the stop codon of rat OSF 2 and the amplification product was purified and then digested with restriction enzymes SmaI and BstEII to give a fragment of about 270 bp. These two fragments were ligated to a vector fragment obtained by digesting a plasmid for constructing an expression vector pcDNA4/Myc-His/type C (Invitrogen) with restriction enzymes EcoRI and BstEII using a ligation kit (TAKARA SHUZO) to give a plasmid designated as pcDNA4/Myc-His/rOSF-2. The total nucleotide sequence of the insert was confirmed by the method described in Example 1-5.

Example 5

Construction of an rOSF-2 Protein Expression Vector

[0147] An expression vector containing the total coding region of rat OSF-2 gene obtained in Example 2 and a CMV promoter was prepared. The pTracer-CMV2/rOSF-2 obtained in Example 4 was digested with restriction enzymes EcoRI and PmeI to give a fragment of about 3300 bp containing the coding region of rat OSF-2 gene, and this fragment was ligated to a vector fragment obtained by digesting said pcDNA4/Myc-His/type C (Invitrogen) with restriction enzymes EcoRI and PmeI using a ligation kit (TAKARA SHUZO) to give a fragment designated as pcDNA4/rOSF-2. The total nucleotide sequence of the insert was confirmed by the method described in Example 1-5.

Example 6

Functional Analysis by Transfection of OSF-2 Gene Into The Rat Heart

[0148] 6-1 Large Scale Purification of Expression Plasmids

[0149] The E. coli strain DH5α was transformed the expression plasmid(pcDNA4/rOSF-2) which prepared in Example 5 and amplified, and purified with EndoFree™ Plasmid Giga kit (QIAGEN), and then dissolved in phosphate-bufferd saline.

[0150] 6-2 Preparation of HVJ-liposomes

[0151] 50 μl of HMG-1, -2 mixture (1 mg/ml, Wako Pure Chemical Industries) was added, to 200 μg of said plasmid solution, and the mixed solution was left at room temperature for 1 hour and then supplied with a BSS solution to a total volume of 200 μml. The mixed solution was added to a glass tube containing a mixed lipid stored at −20° C. (Avanti Polar Lipid Inc., Sigma, Hum. Gene Ther. 8 (17), 2133-2141 (1997), Cell biology, a laboratory hand book, 2nd edition, vol. 4, 122-123 (1998)) and the tube was vigorously shaken on a vortex mixer for 30 seconds and allowed to stand in an incubator at 37° C. for 30 seconds. After 8 cycles of this operation, the glass tube was ultrasonicated for 6 seconds in an ultrasonic generator filled with water and shaken again for 30 seconds on a vortex mixer (120 rpm). Then, 1 ml of HVJ (20000 HAU or higher) (Kaneda: HVJ-liposome method Experimental Procedures for Gene Transfer & Expression Analysis; Yodosha) 70-79 (1997), Saeki, Kaneda: HVJ-liposome vector (Gene Therapy, Handbook for Development and Study: eds. Japan Gene Therapy Association) 429-438 (1999), Hum. Gene Ther. 8 (17), 2133-2141 (1997), Cell biology, a laboratory hand book, 2nd edition, vol. 4, 122-123 (1998)) was dispensed in a plastic dish of 30 mm of diameter and inactivated by irradiation with UV rays at 1980 mJ/cm2 while the cover of the dish being open in a UV crosslinker. This inactivated HVJ was added to the glass tube and placed on ice for 10 minutes, and added 1.3 ml of BSS, and then shaken in a shaking incubator at 37° C. for 1 hour. Then, the total volume of the HVJ-liposome solution (from the glass tube) was gently overlaid on 7.5 ml of a 30% sucrose solution in a 10 ml ultracentrifugal tube and ultracentrifuged at 62,800×g, 4° C. for 1.5 hours. HVJ-liposomes accumulated as white particles on the sucrose solution were recovered with a Pasteur pipette and diluted with BSS to a total volume of 3 ml and then stored at 4° C.

[0152] 6-3 Gene Transfection Into rats

[0153] The HVJ-hposome/DNA solution (at a concentration of 6.7 μg/ml) was injected into the left ventricle of the heart (apical and lateral sites) of 12-weeks old Sprague-Dawley rats (male) in an amount of 100 μl each at 3 sites (a total volume of 300 μl) using a 30-gauge needle (rOSF-2 group). As a control, pcDNA4/His-Myc vector was injected in the same manner (control group).

[0154] 6-4 Echocardiography

[0155] After anesthesia with ketamine (50 mg/ml) and xylazine (10 mg/ml) at 6 weeks post transfection, echocardiography was performed using Core Vision Pro SSA 350A (probe: 7 MHz, Toshiba). The results are shown in Table 1, revealing that cardiac dilatation was induced in rOSF-2 group as demonstrated by significant differences in LVIDD (inner diameter of the end-diastolic left ventricle) and LVIDS (inner diameter of the end-systolic left ventricle) as compared with control group.

1TABLE 1Results of echocardiography (after 6 weeks)Evaluation itemsControlrat OSF-2n1110IVSTD (mm)2.06 ± 0.081.69 ± 0.06#LVIDD (mm)5.78 ± 0.167.68 ± 0.20#LVPWD (mm)2.34 ± 0.091.98 ± 0.05#IVSTS (mm)2.56 ± 0.132.44 ± 0.08 LVIDS (mm)2.54 ± 0.183.81 ± 0.28#LVPWS (mm)2.90 ± 0.122.87 ± 0.07 EDV (μl)166.8 ± 10.6 316.9 ± 17.1# ESV (μl)25.1 ± 4.4 67.1 ± 11.5#FS (%)56.3 ± 2.5 50.8 ± 2.7 #P < 0.01 vs. control Abbreviations: IVSTD: thickness of the end-diastolic interventricular septum LVIDD: inner diameter of the end-diastolic left ventricle LVPWD: thickness of the posterior wall of the end-diastolic left ventricle IVSTS: thickness of the end-systolic interventricular septum LVIDS: inner diameter of the end-systolic left ventricle LVPWS: thickness of the posterior wall of the end-systolic left ventricle EDV: end-diastolic volume ESV: end systolic volume FS: fractional shortening of the inner diameter of the left ventricle.

[0156] 6-5 Hemodynamic Tests

[0157] After anesthesia with pentobarbital hydrochloride (50 mg/ml) at 6 weeks post transfection, intracardiac pressure and blood pressure were measured. The results are shown in Table 2. As compared with control group, significant differences were obtained in LVP (left ventricular pressure), LVEDP (left ventricular end-diastolic pressure), +LVdP/dT and —LVdP/dT in rOSF-2 group, suggesting decreased cardiac function.

2TABLE 2Hemodynamic tests (after 6 weeks)Evaluation itemsControlrat OSF-2n1010BW (g)411.8 ± 6.9415.6 ± 12.3HW (g/kg) 2.63 ± 0.08 2.67 ± 0.12LVW (g/kg) 1.97 ± 0.04 1.99 ± 0.04HR (beats per minute) 444 ± 8 417 ± 12MBP (mmH)128.7 ± 4.7119.7 ± 5.4LVP (mmHg)171.1 ± 7.1143.5 ± 8.7#LVEDP (mmHg) 0.16 ± 0.07 1.00 ± 0.30#+LVdP/dt (mmHg/sec) 8511 ± 468 6120 ± 466#−LVdP/dt (mmHg/sec) 7356 ± 226 5580 ± 470##P < 0.01 vs. control Abbreviations: BW: body weight, HW: heart weight, LVW: left ventricle weight, HR: heart rate, MBP: mean blood pressure, LVEDP: left ventricular end-diastolic pressure LVP: left ventricular pressure LVdP/dT: primary differentiation of maximum left ventricular pressure.

Example 7

Design and Selection of Antisense Oligonucleotides of OSF-2 Gene

[0158] 7-1 Design of Antisense Nucleotide sequences

[0159] Five antisense nucleotide sequences shown as SEQ ID NOs: 12-16 were designed by selecting regions containing an initiation codon AUG but not containing three continuous guanines (triplet G) and incapable of forming a hairpin structure or self-annealing and synthesized by an outer contractor. All the antisense nucleotide sequences are phosphorothioate type.

[0160] 7-2 Selection of Antisense Nucleotide Sequences

[0161] The Myc-His-rOSF-2 fused protein expression vector pcDNA4/Myc-His/rOSF-2 described in Example 5 was introduced into COS-1 cells, and the antisense nucleotide sequences prepared in 1 above were introduced to screen antisense nucleotide sequences inhibiting the expression of Myc-His-rOSF 2 fused protein. The expression level of Myc-His-rOSF-2 fused protein was assayed by ELISA (Enzyme-Linked Immunosorbent Assay) using a Myc-specific monoclonal antibody (Invitrogen). Specifically, COS-1 cells were plated on a 96-well plate at a density of 2×104 cells/well. After 16-24 hours, 320 ng of DNA (pcDNA4/Myc-His/rOSF-2) was dissolved in OPTI MEM I medium (GIBCO) and mixed with the same amount of OPTI-MEM I medium containing 1 μl of LipofectAMINE 2000 reagent (GIBCO), and the mixture was reacted at room temperature for 20 minutes, and then added to COS-1 cells and incubated at 37° C. for transfection. Then, a series of antisense nucleotide sequences dissolved in phosphate-bufferd saline were added to a final concentration of 100 nM 1-4 hours after the addition of DNA and the mixture was incubated for further 3 days at 37° C.

[0162] The culture supernatant was immobilized to an EIA/RIA plate (Costar) by incubating 50 μl thereof at 37° C. for 1-2 hours, and washed twice with 200 μl of Dulbecco's phosphate-buffered saline containing 0.1% Tween (PBST). In order to block non-specific adsorption, the plate was treated with a blocking solution (PBST containing 1% bovine serum albumin) at 37° C. for 1 hour and washed with 200 μl of PBST three times. Then, a horseradish peroxidase-labelled anti-Myc monoclonal antibody (Invitrogen) diluted to 1:4000 in 50 μl of the blocking solution was coupled to the plate by incubation at room temperature for 1 hour and washed with 200 μl of PBST three times and with PBS once. After incubation with 50 μl of TMB (3,3′,5,5′-tetramethylbenzidine) reagent (KPL) at room temperature for 30 minutes, the reaction was stopped by adding 50 μl of 0.1 N sulfuric acid and the absorbance at 450 nm was measured with a microplate reader.

[0163] As a result, a series of antisense nucleotide sequences targeted on the initiation codon all had inhibitory activity against OSF-2 protein production, among which the antisense nucleotide sequence shown as SEQ ID NO: 12 inhibited the expression the most strongly, as shown in FIG. 2.

[0164] Then, a sense nucleotide sequence that is a sense strand corresponding to SEQ ID NO: 12 (SEQ ID NO: 17) and a scramble nucleotide sequence with the 5′, 3′ direction reversed to SEQ ID NO: 12 (SEQ ID NO: 18) were prepared and subjected to experiments as described above at a final concentration of each nucleotide of 10 nM. The results showed that antisense nucleotide sequences had stronger inhibitory activity against OSF-2 protein production than the sense and scramble nucleotide sequences, as shown in FIG. 3.

Example 8

Inhibition of the Expression of OSF-2 Gene by Antisense Nucleotides

[0165] 8-1 Preparation of HVJ-liposomes

[0166] HVJ-liposomes were prepared as described in Example 6 by adding 50 μl of HMG-1,-2 mixture (1 mg/ml, Wako Pure Chemical Industries) to 200 μg of the plasmid solution prepared in Example 6.1 and 1.4 mg of the antisense nucleotide solution selected in Example 7. Sense and scramble nucleotide sequences were also prepared in the same manner.

[0167] 8-2 Gene Transfection into Rats

[0168] The HVJ-liposome/DNA solution was injected into the left ventricle of the heart (apical and lateral sites) of 13-weeks old Sprague-Dawley rats (male) in an amount of 100 μl each at 3 sites (a total volume of 300 μl) using a 30-gauge needle (rOSF-2/antisense group, rOSF-2/sense group and rOSF-2/scramble group). Similarly, pcDNA4/rOSF-2 was injected as a positive control group and pcDNA4/His-Myc vector was injected as a negative control group.

[0169] 8-3 Echocardiography

[0170] After anesthesia with ketamine (50 mg/ml) and xylazine (10 mg/ml) at 3 weeks post transfection, echocardiography was performed using Core Vision Pro SSA 350A (probe: 7 MHz, Toshiba). The results are shown in FIG. 3, revealing that rOSF-2/antisense group inhibited cardiac dilatation similarly to negative control group (control) as demonstrated by significantly smaller LVIDD (inner diameter of the end-diastolic left ventricle) and LVIDS (inner diameter of the end-systolic left ventricle) as compared with positive control group (rOSF-2) or rOSF-2/sense group and rOSF-2/scramble group.

3TABLE 3Results of echocardiographyEvaluationitemControlrat OSF-2antisensesensescramblen66675IVSTD (mm) 1.80 ± 0.11 1.30 ± 0.17* 1.68 ± 0.12 1.26 ± 0.07* 1.26 ± 0.12*LVIDD (mm) 6.18 ± 0.23 7.90 ± 0.29* 6.42 ± 0.09# 7.93 ± 0.18* 7.60 ± 11*LVPWD (mm) 2.22 ± 0.11 1.45 ± 0.15* 2.20 ± 0.13# 1.46 ± 0.11* 1.68 ± 0.07*TVSTS (mm) 3.15 ± 0.13 2.60 ± 0.17* 3.07 ± 0.16 2.50 ± 0.07* 2.60 ± 0.15*LVIDS (mm) 3.07 ± 0.16 3.95 ± 0.24* 3.25 ± 0.15# 4.24 ± 0.22* 4.06 ± 018*LVPWS (mm) 2.92 ± 0.10 2.42 ± 0.16* 2.80 ± 0.17 2.30 ± 0.15 2.66 ± 0.07*EDV (μ1)194.7 ± 16.8338.0 ± 26.8*210.0 ± 6.8#339.2 ± 17.9*307.6 ± 10.4*ESV (μl) 37.8 ± 4.9 69.8 ± 9.8* 43.3 ± 5.1# 82.4 ± 10.2* 73.4 ± 7.5*FS (%) 50.5 ± 1.1 50.1 ± 1.8 49.5 ± 1.7 46.7 ± 1.6 46.7 ± 1.6P < 0.05 vs. control #P<0.05 vs. rat OSF-2 Abbreviations: IVSTD: thickness of the end-diastolic interventricular septum LVIDD: inner diameter of the end-diastolic left ventricle LVPWD: thickness of the posterior wall of the end-diastolic left ventricle IVSTS: thickness of the end-systolic interventricular septum LVJDS: inner diameter of the end-systolic left ventricle LVPWS: thickness of the posterior wall of the end-systolic left ventricle EDV: end-diastolic volume ESV: end-systolic volume FS: fractional shortening of the inner diameter of the left ventricle.

Example 9

Inhibition of the Onset of Heart Failure by Antisense Nucleotides

[0171] 9-1 Preparation of HVJ-liposomes

[0172] HVJ-liposomes were prepared as described in Example 6.2 by adding 50 μl of HMG-1,-2 mixture (1 mg/ml, Wako Pure Chemical Industries) to 1.4 mg of a solution of the antisense nucleotides selected in Example 7 dissolved in BSS buffer. Sense nucleotides were also prepared in the same manner.

[0173] 9-2 Gene Transfection into Rats

[0174] The HVJ-liposome/DNA solution was injected into the left ventricle of the heart (apical and lateral sites) of 13-weeks old Dahl-S rats (DIS/Eis, Eisai, male) raised on an 8% salt diet from the age of 8 weeks in an amount of 75 μl each at 4 sites (a total volume of 300 μl) using a 30-gauge needle (antisense group: 13 rats, sense group: 13 rats). After transfection, the rats were continuously raised on an 8% salt diet and the survival rate was tested to show an improvement in survival rate 30 weeks post transfection in antisense group (100%) as compared with sense group (61.5%).

Example 10

Preparation of Human OSF-2 Reporter Plasmids

[0175] 10-1 Cloning of an Upstream Region of Human OSF-2 Gene

[0176] Ten subpools of about 25,000 clones (a total of about 250,000 clones) prepared from a human genomic library (Clontech) inserted into EMBL-3 vector were screened by PCR using primer (10) 5′-AAGAATATTAAAAGTTATTTGTGGGCAGGAGACAGATG-3′ (SEQ ID NO: 22) and primer (11) 5′-CATTTAAAAGCCTATCAAGTGTCAGGTCCACTCTC-3′ (SEQ ID NO: 23) designed on the basis of the nucleotide sequence of a draft sequence containing an upstream region of human OSF-2 gene (GenBank Accession No. AL138679) to identify two positive subpools, and these subpools were screened by hybridization using the fragment amplified by the above mentioned PCR as a probe labeled with alkaline phosphatase using AlkPhos Direct™ (Amersham Pharmacia) to give two positive clones human OSF-2 genes #1, 2. The insert fragment in human OSF-2 gene #2 was integrated into the XhoI recognition site of pBluescript II (Stratagene) to give pB-hOSFg#2, which was partially sequenced according to the method of Example 1-5. The resulting clone had a length of about 13.5 kb corresponding to nucleotides 16397-30002 of the human draft sequence (GenBank Accession No. AL138679 version 11) and contained a region upstream of intron 2 of human OSF-2 gene. The total nucleotide sequence was determined from the SpeI recognition site located about 2 kb upstream of the initiation codon (ATG) to the initiation codon. This nucleotide sequence of about 2 kb is shown as SEQ ID NO: 24. This nucleotide sequence of about 2 kb contained variations in 4 bases as compared with the sequence of GenBank Accession No. AL138679 version 11 at nucleotides 764 G (T), 936 T (C), 1099 C m and 2106 G (C) starting from the SpeI recognition site (with the nucleotide in AL138679 version 11 shown in parentheses).

[0177] 10-2 Preparation of Human OSF-2 Reporter Plasmids

[0178] A region extending from about 2 kb upstream of the initiation codon to immediately before the initiation codon was amplified by PCR using human OSF-2 gene #2 obtained in Example 10-1 as a template and primers (12) 5′-TGAGCATATATCATGCTTTC-3′ (SEQ ID NO: 25) and (13) 5′-AATCATCTCGAGTCTCTCCGTTGCAGTTAGTCCCC-3′ (SEQ ID NO: 26). Primer (13) was designed to insert a restriction enzyme XhoI recognition site into the 5′ end, and this amplified fragment was digested with restriction enzymes SpeI and XhoI to give a fragment of about 2 kb, which was then ligated to a vector fragment of pGL3-enhancer (Promega) digested with restriction enzymes NheI and XhoI located upstream of the luciferase gene using a ligation kit (TAKARA SHUZO CO., LTD.) to give pGL3-hOSFgE. The nucleotide sequence of the insert was determined according to the method of Example 1-5 to confirm that it was identical with the nucleotide sequence determined in Example 10-1.

Example 11

Screening of Compounds Influencing the Expression of Human rOSF-2 Gene

[0179] 11-1 Reporter Assay Using COS-1 Cells

[0180] COS-1 cells were plated on a 96-well plate at a density of 3×104 cells/well and the plate was incubated at 37° C. for 16-24 hours and then transiently transfected with OSF-2 reporter plasmid pGL3-hOSFgE shown in Example 10 using LipofectAMINE 2000 reagent (GIBCO), and after incubation for 24 hours at 37° C., the medium was replaced. After 24 hours, candidate compounds were added and after further 24 hours, luciferase activity was assayed. Luciferase activity was assayed according to the protocol of a luciferase assay system (Promega) and detected with 1420 multilabel counter (Wallac). Similar experiments were performed on pGL3-control (Promega) containing a luciferase gene linked to the downstream of SV40 promoter as a control. A number of compounds were screened by this method to show that 2-chloroadenosine 5′-triphosphate tetrasodium and Metrifudil (N-[(2-methylphenyl)methyl]-adenosine) inhibit luciferase activity specifically to OSF-2 promoter. These compounds have the following chemical structural formulae.

[0181] 2-Chloroadenosine 5′-triphosphate tetrasodium:

[0182] Metrifudil (N-[(2-methylphenyl)methyl]-adenosine):

[0183] 11-2 Expression Analysis Using MC3T3-E1 Cells

[0184] Murine osteoblast-like cells MC3T3-E1 (purchased from RIKEN Gene Bank) originally expressing OSF-2 were plated on a 6-well plate at a density of 5×105 cells/well, and the plate was incubated for 24 hours at 37° C. After 24 hours, said compounds were added at a concentration of 30 μM and cells were recovered after further 24 hours to prepare total RNA from the cells using RNeasy®Mini (QIAGEN) and the expression levels of OSF-2 mRNA and internal standard GAPDH mRNA were assayed by PCR assay system according to the method of Example 3-2 (the expression level of OSF-2 mRNA was standardized by the expression level of internal standard GAPDH mRNA). As a result, it was confirmed that 2-chloroadenosine triphosphate tetrasodium and Metrifudil inhibited the expression of OSF-2 mRNA.

[0185] Thus, it was shown that compounds influencing the expression of OSF-2 gene can be found by using the screening system shown in the present invention.

	Number	Date	Country
Parent	PCT/JP01/07787	Sep 2001	US
Child	10383241	Jul 2003	US

Remedies for heart failure

Information

Publication Number

Date Filed

Date Published

Inventors

Original Assignees

CPC

US Classifications

International Classifications

Abstract

Description

Claims

Priority Claims (1)

Parent Case Info

Continuations (1)