JP2007191424A - Expression activator for adiponectin receptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expression activator for an adiponectin receptor useful for preventing or treating metabolic syndrome, obesity, hepatic fibrosis, malignant tumor, etc. <P>SOLUTION: The expression activator for AdipoR1 and AdipoR2 (adiponectin receptor) comprises a fibrate drug such as bezafibrate as an active ingredient. An agent for preventing or treating the metabolic syndrome, obesity, hepatic fibrosis, malignant tumor, etc., accompanied with fatness using the expression activator is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an adiponectin receptor expression activator. More specifically, the present invention relates to a metabolic syndrome containing a fibrate drug having an adiponectin receptor expression activation action as an active ingredient, particularly a metabolic syndrome, obesity, liver fibrosis or malignant tumor associated with obesity. It is about.

  Adiponectin is a kind of adipocytokine which is a physiologically active substance secreted from adipocytes, and is known as a protective factor against insulin resistance, liver fibrosis, malignant tumors and arteriosclerosis. For example, in patients with diabetes or obesity, blood adiponectin levels are low, hepatitis plays an important role as a protective factor for liver fibrosis, and blood adiponectin levels in patients with metabolic syndrome Has decreased in inverse proportion to the degree of obesity and has been reported to be inversely correlated with the insulin resistance index (see Non-Patent Document 1). Adiponectin is attracting attention as a target molecule for PPAR (peroxisome proliferator activated receptor) γ in fat cells of obese patients with insulin resistance. Specifically, since the blood adiponectin concentration is significantly increased by PPARγ agonists typified by insulin sensitivity enhancers such as thiazolidinedione (hereinafter referred to as TZD) derivatives as antidiabetics, TZD derivatives are obese It is thought that by improving fat function abnormality, secretion of adiponectin is promoted from adipose tissue, and as a result, insulin resistance in metabolic syndrome accompanied by obesity is improved (see Non-Patent Document 1).

Adiponectin receptor (hereinafter sometimes referred to as AdipoR) is present in liver and skeletal muscle, which are important tissues for regulating insulin sensitivity, and is involved in glucose uptake into tissues and β-oxidation of fatty acids via PPARα. Thus, it has been clarified that a major part of the function of adiponectin is mediated by an adiponectin receptor (see Non-Patent Document 2).
There are two subtypes of AdipoR, AdipoR1 and AdipoR2 (see Non-Patent Document 3). AdipoR1 is distributed in the whole body tissue, and AdipoR2 is mainly distributed in the liver. Recently, it was reported that, in the liver, stimulation of AdipoR1 showed AMP kinase activation (gluconeogenesis suppression) action, and AdiopoR2 stimulation showed an action of enhancing fatty acid β-oxidation through activation of PPARα (non-) (See Patent Document 4).

  In general, when the agonist concentration for the receptor increases, the biological feedback mechanism decreases the sensitivity to the agonist due to a decrease in the expression level of the receptor in the target organ, etc., and resistance increases only by increasing the blood agonist concentration. It is thought that it becomes difficult to act gradually. Similarly, regarding the relationship between adiponectin and adiponectin receptor, it is considered that the sensitivity to adiponectin in target organs (liver, skeletal muscle, etc.) is caused by an increase in blood adiponectin concentration. Therefore, a drug capable of increasing the adiponectin receptor expression level to increase the sensitivity to adiponectin independently of the blood adiponectin concentration and sustain the action for a longer period of time is desired.

  As mentioned above, activating the action of adiponectin by increasing the expression level of adiponectin receptor improves insulin resistance in metabolic syndrome or suppresses liver fibrosis, malignant tumor or arteriosclerosis, etc. The drug having this action is effective in the treatment of metabolic syndrome, in particular, metabolic syndrome associated with obesity, obesity, liver fibrosis, malignant tumor or arteriosclerosis (non-patented). Reference 1 and 5).

  The mechanism of action of fibrates is diverse and has unique properties for each drug, but acts as a ligand for PPARα. PPAR (Peroxisome Proliferator Activated Receptor) is a ligand-responsive transcription factor and is a nuclear receptor with glucocorticoid, androgen, progesterone, mineralocorticoid, estrogen, activated vitamin D, etc. as a ligand. It belongs to the family and there are subtypes of PPARα, γ and δ.

PPARα is expressed in the liver, myocardium, gastrointestinal tract, vascular endothelial cells, aortic smooth cells, macrophages and lymphocytes, and is related to lipid catabolism such as increased fatty acid β-oxidation and activation of lipoprotein lipase (LPL) in the liver. is doing.
PPARγ is expressed in adipocytes and is related to lipid anabolism such as adipocyte differentiation and fat synthesis promotion in adipose tissue.
PPARδ is expressed in skeletal muscle and is related to activation of fatty acid oxidation.

The liver is involved in lipid metabolism and gluconeogenesis, and skeletal muscle is responsible for sugar uptake and lipid metabolism. On the other hand, it is reported that adipose tissue is a fat storage organ and secretes a hormone called adipocytokine, and the secreted adipocytokine is involved in systemic glycolipid metabolism and various inflammatory conditions. (See Non-Patent Document 6).
Therefore, in the glycolipid metabolism, the functions of the liver, skeletal muscle, and adipose tissues and the factors that control them are clearly different (see Non-Patent Document 7).

  There is a report that bezafibrate, which is a fibrate, increases adiponectin gene expression and increases plasma adiponectin concentration in diabetes model animals with obesity (see Non-Patent Document 8). There is no known action to improve the susceptibility by activating. As described above, only the effect of increasing the concentration of adiponectin in blood is considered to cause a decrease in sensitivity to adiponectin in target organs (liver, skeletal muscle, etc.), and the long-term administration of the drug may lead to attenuation of adiponectin action. On the other hand, a drug having an adiponectin receptor expression-stimulating effect is less resistant, so it is used for the treatment of chronic diseases that require long-term administration such as metabolic syndrome associated with obesity, obesity, liver fibrosis, and malignant tumors. As a drug, it is preferable to a drug having only a blood adiponectin concentration increasing action.

  In addition, a report that Wy-14463 and bezafibrate, which are fibrates, increased the expression level of AdipoR2 mRNA in macrophage-derived cultured cells (see Non-Patent Document 9) and Wy-14643 in white adipose tissue in KKAy mice. There is a report that the expression level of AdipoR1 and AdipoR2 mRNA was increased (see Non-Patent Document 10). However, since PPARα is not expressed in adipose tissue, it is considered that Wy-14643 does not act as a ligand for PPARα in adipose tissue. Furthermore, as described above, the functions of adiponectin receptors in macrophages, adipose tissue, liver and skeletal muscle tissues are completely different, and adiponectin receptors in macrophage-derived cells and white adipose tissues are metabolically associated with obesity. There is no report of any physiological significance in pathologies such as syndrome, obesity, liver fibrosis, and malignant tumors.

  That is, none of the above-mentioned documents describes or suggests the expression-stimulating action of adiponectin receptors in the liver and skeletal muscle by fibrates.

  By the way, metabolic syndrome is a pathological condition that is associated with risk factors such as high triglyceride / low HDL-cholesterolemia, abnormal glucose metabolism, and hypertension against the background of visceral fat accumulation. Even if each of them is mild, the risk of developing an arteriosclerotic disease increases due to the combination, and it has been attracting attention as a high-risk group of arteriosclerotic diseases. WHO shows at least one symptom of type 2 diabetes, impaired glucose tolerance and insulin resistance, and is associated with hypertension, obesity, lipid metabolism abnormalities (hypertriglyceridemia / low HDL-cholesterolemia) and microalbuminuria. The case where at least two symptoms are shown is defined as metabolic syndrome.

  NCEP ATP III (National Cholesterol Education Program: Adult Treatment Panel III, 16, 2001) diagnoses metabolic syndrome when three or more of the following criteria apply.

  For the treatment of metabolic syndrome, pharmacotherapy for individual risk factors is currently being attempted. That is, fibrates or statins for high triglycerides and low HDL cholesterolemia; sulfonylureas, fast-acting insulin secretagogues, α-glucosidase inhibitors or insulin sensitizers for abnormal glucose metabolism; Angiotensin converting enzyme inhibitors or adrenergic α receptor antagonists are used. However, for obesity, which is a background disease of metabolic syndrome, exercise therapy and diet therapy are mainly used, and only central appetite suppressants are used as drug therapy.

  Recently, bezafibrate has been reported to suppress the onset of myocardial infarction in patients with metabolic syndrome (see Non-Patent Document 11). However, this report relates to a symptomatic treatment that suppresses one symptom of a complicated metabolic syndrome, and does not fundamentally treat the metabolic syndrome by treating obesity, which is a background disease.

Maeda Hoichi et al., Adiposcience, 2004, Volume 1, p. 247-257 Toshimasa Yamauchi et al., Molecular Medicine Special Issue, Frontline of Lifestyle-related Diseases, No. 42, p. 125-133 Yamauchi et al., Nature, 2003, 423, p. 762-769 Masaki Kobayashi et al., Journal of Japanese Society of Obesity, 2005, Volume 11 (Supplement), p. 152 Tamura Shinji et al., BIO Clinica, 2004, Vol. 19, p. 29-34 Maeda Hoichi et al., Adiposcience, 2004, Volume 1, p. 241-245 Tanaka Toshiya et al., Molecular Biology of Metabolic Syndrome Pathology, Nanzando, 2005, p. 141-155 Mori et al., Endcrine, 2004, 25, p. 247-251 Chineti G. Et al., Biochem Biophys Res Comm. 2004, 314, p. 151-158 Tsuchida et al., Diabetes, 2005, 54, p. 3358-3370 Alexander T. Et al., Arch Inter. 2005, 165, p. 1154-1160

  The present invention provides an adiponectin receptor expression activator containing a fibrate as an active ingredient, and a preventive or therapeutic agent for metabolic syndrome, obesity, liver fibrosis or malignant tumor with obesity using the same. Let it be an issue.

  As a result of intensive studies on the above problems, the present inventors have shown that fibrate drugs exhibit excellent adiponectin receptor expression activation action, and in particular, bezafibrate of fibrate drugs activates adiponectin receptor expression in liver and skeletal muscle tissues. The present invention was completed by finding that it exhibits an action.

  That is, the gist of the present invention is that the liver and skeletal muscle adiponectin receptor expression activator containing fibrates and the metabolic syndrome associated with obesity containing fibrates as active ingredients, obesity, liver fibrosis or malignant Lies in the prevention or treatment of tumors.

  Since the prophylactic or therapeutic agent according to the present invention has an excellent adiponectin receptor expression activating action of liver and skeletal muscle, it can be used for diseases such as metabolic syndrome associated with obesity, obesity, liver fibrosis, malignant tumor, etc. .

  Examples of fibrates include bezafibrate, beclobrate, vinylfibrate, ciprofibrate, clinofibrate, clofibrate, clofibrate aluminum, clofibric acid, etofibrate, fenofibrate, gemfibrozil, nicofibrate, pilifibrate, lonifibrate, sim Examples include fibrate, theofibrate, AHL-157, and bezafibrate is preferred.

  In the present invention, an adiponectin receptor means AdipoR1 and AdipoR2.

  The adiponectin receptor expression activator of the present invention can be used for the prevention or treatment of metabolic syndrome associated with obesity, obesity, liver fibrosis, and malignant tumors. The target malignant tumors include breast cancer, endometrial cancer, colon cancer, renal cell cancer, esophageal adenocarcinoma, esophageal cancer, colon cancer, rectal cancer, liver cancer, gallbladder cancer, pancreatic cancer, kidney cancer, non-Hodgkin lymphoma, Examples include multiple myeloma, stomach cancer, prostate cancer, uterine cancer, cervical cancer, ovarian cancer and the like.

  Examples of the dosage form of the preventive or therapeutic agent according to the present invention include oral administration agents such as powders, granules, tablets and capsules. For example, in the case of tablets, these orally administered agents can be produced by adding tablets, disintegrants, lubricants and the like necessary for the active ingredient and tableting them by a conventional method. In addition, the dose of the active ingredient can be appropriately determined depending on the age, body weight, degree of disease, etc. of the patient. For example, in the case of bezafibrate, it is usually administered in the range of 100 to 1000 mg, preferably 400 to 600 mg per day for an adult.

  The contents of the present invention will be described in more detail in the following examples, but the present invention is not limited to the contents.

[Example 1]
Bezafibrate 100 or 300 μmol / L, or fenofibrate 100 or 300 μmol / L or a solvent (DMSO [final concentration 1%]) (control group) was added to mouse hepatocyte-derived Hepa1-6 cultured cells (manufactured by American Type Culture Collection). 24 hours later, Total RNA was purified using SV Total RNA Isolation System ^™ (Promega Corporation). Using the obtained RNA as a template, a reverse transcription reaction was performed with ExScript ^™ RT reagent Kit (Takara Bio Inc.), and the sample was converted to cDNA. Using this as a template, a primer of AdipoR1 known in the literature (Bluer M. et al., 2005, Biochem Biophys Res Comm., 329, pp. 1271-2132) or Perfect RealTime support system AdipoR2 primer (Takara Bio Inc.) and real-time quantification with SYBR ^™ Premix ExTaq ^™ (Takara Bio Inc.) PCR was performed. From this result, the amount of AdipoR1 and AdipoR2 mRNA in each tissue was calculated. In addition, the amount of ribosomal RNA was similarly calculated using Predeveloped TaqMan Assay Reagents ribosomal RNA ribosomal RNA (Applied Biosystems Japan Co., Ltd.), which is an internal standard substance, and the ratio to this value (target mRNA amount / ribosomal amount) Was analyzed as each mRNA expression level. For the reaction, Applied Biosystems GeneAmp5700 SDS (Applied Biosystems Japan Co., Ltd.) was used. The results are shown in FIG.

  Bezafibrate significantly increased the expression levels of AdipoR1 and AdipoR2 in Hepa1-6 cultured cells compared to the control group.

[Example 2]
Genetic leptin receptor-deficient mice (BKS.Cg− + Leptdb / + Leptdb / Jcl mice; hereinafter referred to as db / db mice) which are type 2 diabetes model mice, 1% methylcellulose solution (control group), bezafibrate 100 mg / kg or 300 mg / Kg or fenofibrate 300 mg / kg was orally administered once a day. After 8 weeks of administration, anesthesia was performed by intraperitoneal administration of 20% chloral hydrate (Wako Pure Chemical Industries, Ltd.), and liver tissue and skeletal muscle tissue were removed. Total RNA was extracted from the extracted tissue using an RNA extraction reagent ISOGEN (Nippon Gene Co., Ltd.) and further purified using RNeasy Micro Kit (Qiagen Co., Ltd.). Using the obtained RNA as a template, a reverse transcription reaction is performed with ExScript ^™ RT reagent Kit (Takara Bio Inc.) to convert the sample into cDNA. Using this as a template, real-time quantitative PCR was performed in the same manner as described in Examples, and the amounts of AdipoR1 and AdipoR2 mRNA expressed in each tissue were quantified. The results are shown in FIG.

  Bezafibrate significantly increased the expression levels of AdipoR1 and AdipoR2 in liver and skeletal muscle compared to the control group.

Example 3
db / db mice were orally administered once daily with 1% methylcellulose solution (control group), bezafibrate 100 mg / kg or 300 mg / kg, or fenofibrate 300 mg / kg. After administration for 8 weeks, blood was collected from the tail vein, and blood glycated hemoglobin level, plasma glucose concentration, plasma triglyceride concentration and plasma adiponectin concentration were measured. The results are shown in FIG.

  Repeated administration of bezafibrate significantly reduced the blood glycated hemoglobin level, plasma glucose concentration and plasma triglyceride concentration after 4 weeks compared to the control group. On the other hand, repeated administration of fenofibrate significantly reduced the plasma triglyceride concentration after 4 weeks compared to the control group.

  Thus, bezafibrate and fenofibrate improved diabetes and hyperlipidemia in db / db mice.

  From the above, it was shown that bezafibrate increases the expression levels of AdipoR1 and AdipoR2 in the liver and skeletal muscle and activates adiponectin action in the liver and skeletal muscle. Therefore, it is applied to the prevention or treatment of metabolic syndrome associated with obesity, obesity, liver fibrosis or malignant tumor.

  Since the prophylactic or therapeutic agent according to the present invention has an excellent adiponectin receptor (AdipoR1 and AdipoR2) expression activation action in the liver and skeletal muscle, diseases such as metabolic syndrome associated with obesity, obesity, liver fibrosis, malignant tumor, etc. Can be used.

It is the graph which showed the expression level of AdipoR1 and AdipoR2 mRNA in the cell 24 hours after adding bezafibrate and fenofibrate to mouse hepatocyte-derived Hepa1-6 cultured cells. From the left, the bar graphs are: Control: control group; BF100: bezafibrate added at 100 μmol / L; BF300: bezafibrate added at 300 μmol / L; FEN100: fenofibrate added at 100 μmol / L; FEN300: fenofibrate added at 300 μmol / L; AdipoR1 and AdipoR2 mRNA expression levels are shown respectively. A vertical axis | shaft shows the average value (%) and standard error of the expression level of each group which made the mRNA expression level of the control group 100%. In the figure, * and ** indicate that statistical significance was recognized at significance levels of 5% and less than 1%, respectively. It is the graph which showed the expression levels of AdipoR1 and AdipoR2 mRNA in (A) liver and (B) skeletal muscle of db / db mice after repeated administration of bezafibrate and fenofibrate for 8 weeks, respectively. The bar graph shows, from the left, AdipoR1 and AdipoR2 mRNA expression levels of Control: control group; BF100: bezafibrate 100 mg / kg administration group; BF300: bezafibrate 300 mg / kg administration group; FEN300: fenofibrate 300 mg / kg administration group; A vertical axis | shaft shows the average value (%) and standard error of the expression level of each group when the mRNA expression level of a control group is 100%. In the figure, * and ** have the same meaning as in FIG. It is the graph which showed the diabetes and hyperlipidemia improvement effect of db / db mouse by repeated administration for eight weeks with bezafibrate and fenofibrate. (A) is glycated hemoglobin value (%); (B) is plasma glucose concentration (mg / dL); (C) is plasma triglyceride concentration (mg / dL); (D) is plasma adiponectin concentration (ng / mL) ). In each graph, N is a normal control group; C is a control group; BF100, BF300, and FEN300 have the same meaning as in FIG. Each vertical axis shows the average value and standard error. In the figure, # and ## indicate that a statistically significant difference was observed between the normal control group and the control group at a significance level of 5% and less than 1%, respectively, and * and ** have the same meaning as in FIG. .

Claims (6)

An adiponectin receptor expression activator containing a fibrate as an active ingredient. A preventive or therapeutic agent for metabolic syndrome associated with obesity, liver fibrosis, obesity or malignant tumor, comprising a fibrate as an active ingredient. The preventive or therapeutic agent according to claim 2 for metabolic syndrome associated with obesity. The prophylactic or therapeutic agent according to claim 2 for obesity. The prophylactic or therapeutic agent according to claim 2 for liver fibrosis. The expression activator or preventive or therapeutic agent according to any one of claims 1 to 5, wherein the fibrate is bezafibrate.

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