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Yasuyoshi Ouchi

Publications and source records attributed to Yasuyoshi Ouchi.

At least 19 recordsLinked to original sources
PubMed2007

Beta-defensin overexpression induces progressive muscle degeneration in mice.

Defensins comprise a family of cationic antimicrobial peptides characterized by conserved cysteine residues. They are produced in various organs including skeletal muscle and are identified as key elements in the host defense system as potent effectors. At the same time, defensins have potential roles in the regulation of inflammation and, furthermore, can exert cytotoxic effects on several mammalian cells. Here, we developed transgenic mice overexpressing mouse beta-defensin-6 to explore the pathophysiological roles of the defensin family as a novel mediator of inflammatory tissue injury. Unexpectedly, the transgenic mice showed short lifespan, poor growth, and progressive myofiber degeneration with functional muscle impairment, predominant centronucleated myofibers, and elevated serum creatine kinase activity, as seen in human muscular dystrophy. Furthermore, some of the transgenic myofibers showed IkappaBalpha accumulation, which would be related to the myofiber apoptosis of limb-girdle muscular dystrophy type 2A. The present findings may unravel a concealed linkage between the innate immune system and the pathophysiology of degenerative diseases.

Aging↗
PubMed2007

Q89R polymorphism in the LDL receptor-related protein 5 gene is associated with spinal osteoarthritis in postmenopausal Japanese women.

STUDY DESIGN: An association study investigating the genetic etiology for spinal osteoarthritis. OBJECTIVE: To determine the association of single-nucleotide polymorphism (SNP) causing an amino-acid change (Q89R) in the low-density lipoprotein receptor-related protein 5 (LRP5) coding region with spinal osteoarthritis. SUMMARY OF BACKGROUND DATA: Wnt/beta-catenin signaling pathway regulates bone density through a Wnt coreceptor LRP5. This pathway is also involved in cartilage development and homeostasis, suggesting that genetic variation in LRP5 gene may affect the pathogenesis of cartilage-related diseases, such as osteoarthritis. METHODS: We evaluated the presence of osteophytes, endplate sclerosis, and narrowing of disc spaces in 357 Japanese postmenopausal women. Missense coding SNP for Q89R of LRP5 gene was determined using TaqMan polymerase chain reaction (PCR) method. RESULTS: We found that subjects without the R allele (QQ; n = 321) had a significantly lower osteophyte formation score than did subjects bearing at least one R allele (QR + RR; n = 36) (7.80 vs. 10.89, P = 0.0019 by analysis of covariance). CONCLUSIONS: We suggest that a genetic variation at the LRP5 gene locus is associated with spinal osteoarthritis, in line with the involvement of the LRP5 gene in the bone and cartilage metabolism.

Aged↗
PubMed2006

Signaling pathway of nitric oxide production induced by ginsenoside Rb1 in human aortic endothelial cells: a possible involvement of androgen receptor.

Ginsenosides have been shown to stimulate nitric oxide (NO) production in aortic endothelial cells. However, the signaling pathways involved have not been well studied in human aortic endothelial cells. The present study was designed to examine whether purified ginsenoside Rb1, a major active component of ginseng could actually induce NO production and to clarify the signaling pathway in human aortic endothelial cells. NO production was rapidly increased by Rb1. The rapid increase in NO production was abrogated by treatment with nitric oxide synthetase inhibitor, L-NAME. Rb1 stimulated rapid phosphorylation of Akt (Ser473), ERK1/2 (Thr202/Thr204) and eNOS (Ser1177). Rapid phosphorylation of eNOS (Ser1177) was prevented by SH-5, an Akt inhibitor or wortmannin, PI3-kinase inhibitor and partially attenuated by PD98059, an upstream inhibitor for ERK1/2. Interestingly, NO production and eNOS phosphorylation at Ser1177 by Rb1 were abolished by androgen receptor antagonist, nilutamide. The results suggest that PI3kinase/Akt and MEK/ERK pathways and androgen receptor are involved in the regulation of acute eNOS activation by Rb1 in human aortic endothelial cells.

Amino Acid Sequence↗
PubMed2006

Gas6/Axl-PI3K/Akt pathway plays a central role in the effect of statins on inorganic phosphate-induced calcification of vascular smooth muscle cells.

Apoptosis is essential for the initiation and progression of vascular calcification. Recently, we showed that 3-hydroxy-3-methylglutaryl (HMG) CoA reductase inhibitors (statins) have a protective effect against vascular smooth muscle cell calcification by inhibiting apoptosis, where growth arrest-specific gene 6 (Gas6) plays a pivotal role. In the present study, we clarified the downstream targets of Gas6-mediated survival signaling in inorganic phosphate (Pi)-induced apoptosis and examined the effect of statins. We found that fluvastatin and pravastatin significantly inhibited Pi-induced apoptosis and calcification in a concentration-dependent manner in human aortic smooth muscle cells (HASMC), as was found with atorvastatin previously. Gas6 and its receptor, Axl, expression were downregulated in the presence of Pi, and recombinant human Gas6 (rhGas6) significantly inhibited apoptosis and calcification in a concentration-dependent manner. During apoptosis, Pi suppressed Akt phosphorylation, which was reversed by rhGas6. Wortmannin, a specific phosphatidylinositol 3-OH kinase (PI3K) inhibitor, abolished the increase in Akt phosphorylation by rhGas6 and eliminated the inhibitory effect of rhGas6 on both Pi-induced apoptosis and calcification, suggesting that PI3K-Akt is a downstream signal of the Gas6-mediated survival pathway. Pi reduced phosphorylation of Bcl2 and Bad, and activated caspase 3, all of which were reversed by rhGas6. The inhibitory effect of statins on Pi-induced apoptosis was accompanied by restoration of the Gas6-mediated survival signal pathway: upregulation of Gas6 and Axl expression, increased phosphorylation of Akt and Bcl2, and inhibition of Bad and caspase 3 activation. These findings indicate that the Gas6-mediated survival pathway is the target of statins' effect to prevent vascular calcification.

Androstadienes↗
PubMed2006

A functional single nucleotide polymorphism in the vitamin-K-dependent gamma-glutamyl carboxylase gene (Arg325Gln) is associated with bone mineral density in elderly Japanese women.

The vitamin-K-dependent gamma-glutamyl carboxylase (GGCX) carboxylates vitamin-K-dependent proteins including bone Gla protein (osteocalcin) and matrix Gla protein, which play important roles in bone metabolism. Therefore, GGCX polymorphism might explain in part individual susceptibility to osteoporosis. In the present study, polymorphisms in the exons of this gene were screened in Japanese elderly women and a non-synonymous single nucleotide polymorphisms (SNP) were found; c.8762 G>A; (Arg325Gln). When the kinetic parameters of GGCX325-Gln and GGCX325-Arg were compared in vitro, Vmax/Km was significantly higher for GGCX325-Gln (944.4+/-9.21 pmol/30 min/mg/mM FLEEL) than for GGCX325-Arg (671.9+10.79 pmol/30 min/mg/mM FLEEL) (p=0.018). Then, association study of this polymorphism with forearm bone mineral density (BMD) of Japanese postmenopausal women (n=500, age 73.6+/-5.74) was conducted. As a result, the body mass index (BMI)-adjusted Z score in the subpopulation older than 75 years (n=207) was higher in those with 325-Gln (0.650+/-0.883, mean+/-SD) than those with 325-Arg/Gln or 325-Arg (0.133+/-0.650) (p=0.0383). This is the first report to demonstrate the different activities of GGCX between the common genotypes and their association with BMD.

Aged↗
PubMed2006

Statins protect human aortic smooth muscle cells from inorganic phosphate-induced calcification by restoring Gas6-Axl survival pathway.

Vascular calcification is clinically important in the development of cardiovascular disease. It is reported that hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (statins) inhibited vascular calcification in several clinical trials. However, the mechanism is poorly understood. Recently, it has been suggested that apoptosis is one of the important processes regulating vascular smooth muscle cell (VSMC) calcification. In this study, we investigated the effect of statins on VSMC calcification by testing their effect on apoptosis, focusing in particular on regulation of the survival pathway mediated by growth arrest-specific gene 6 (Gas6), a member of the vitamin K-dependent protein family, and its receptor, Axl. In human aortic smooth muscle cells (HASMC), statins significantly inhibited inorganic phosphate (Pi)-induced calcification in a concentration-dependent manner (reduced by 49% at 0.1 micromol/L atorvastatin). The inhibitory effect of statins was mediated by preventing apoptosis, which was increased by Pi in a concentration-dependent manner, and not by inhibiting sodium-dependent phosphate cotransporter (NPC) activity, another mechanism regulating HASMC calcification. Furthermore, the antiapoptotic effect of statins was dependent on restoration of Gas6, whose expression was downregulated by Pi. Restoration of Gas6 mRNA by statins was mediated by mRNA stabilization, and not by an increase in transcriptional activity. Suppression of Gas6 using small interfering RNA and the Axl-extracellular domain abolished the preventive effect of statins on Pi-induced apoptosis and calcification. These data demonstrate that statins protected HASMC from Pi-induced calcification by inhibiting apoptosis via restoration of the Gas6-Axl pathway.

Aorta↗
PubMed2006

Diethylstilbestrol increases the density of prolactin cells in male mouse pituitary by inducing proliferation of prolactin cells and transdifferentiation of gonadotropic cells.

Diethylstilbestrol (DES) has been implicated in mammalian abnormalities. We examined the effects of DES on follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL) cells in the pituitaries of male mice treated with various doses of DES for 20 days. DES reduced the density of FSH and LH cells in a dose-dependent manner, but increased that of PRL cells. When the expression of estrogen receptor (ER) alpha and beta was assessed, an induction of ERbeta by DES was found predominantly in PRL cells. However, since these effects were abolished in ERalpha knockout mice, DES appears to act primarily through ERalpha. When the expression of Ki-67 and Pit-1 in PRL cells was examined at various time-points after DES treatment, some PRL cells became Ki-67 positive at 10-15 days, and Pit-1-positive cells were increased at 5-15 days. Furthermore, some FSH and LH cells became Pit-1 positive, and co-localized with PRL at 5-10 days. Our results indicate that DES increases PRL cells by inducing proliferation of PRL cells and transdifferentiation of FSH/LH cells to PRL cells.

Animals↗
PubMed2006

[An elderly case with nontuberculous mycobacteria acompanied by unilateral massive pleural effusion following the video-assisted thoracic surgery (VATS) for lung cancer].

We report an elderly case with nontuberculous mycobacteria (NTM). Four years after left lung upper lobectomy due to lung cancer by the video-assisted thoracic surgery (VATS), an 81 year-old patient complained of general fatigue and appetite loss. Although he did not exhibit fever or respiratory tract symptoms, a Chest X ray film revealed unilateral massive pleural effusion in the left lung. NTM (Runyon classification type II) was grown in the sputum culture. Neither mycobacterium tuberculosis DNA nor M. avium-intracellulare complex DNA was detected by polymerase chain reaction. The pleural effusion adenosine deaminase (ADA) activity was 127.6U/l. NTM was considered as the most probable diagnosis. After admission his condition and appetite improved. Chest computed tomography (CT) scan showed reduction of left pleural effusion, but another pulmonary nodule lesions were sustained. Although the abnormal findings on chest CT did not totally resolve, we did not prescribe antituberculosis drugs, based on the comprehensive assessment of his NTM disease state. The pathogenesis and diagnosis of HTM in elderly cases was discussed.

Aged, 80 and over↗
PubMed2006

Prevalence of metabolic syndrome in the general Japanese population in 2000.

To determine the prevalence of metabolic syndrome in the Japanese general population, we analyzed data from a nationwide survey conducted in 2000. According to the Japanese new diagnostic criteria for metabolic syndrome in 2005, we analyzed 3,264 people aged from 20 to 79 (men, 1,917; women, 1,347) from the total participants. The incidence of metabolic syndrome was 7.8%. Men had a higher incidence (12.1%) than women (1.7%). Most of the women satisfying the criteria were 50 years old or over, while the incidence in men started to rise from their 30s. When we applied the criteria of Adult Treatment Panel III, the incidence was about 3-fold higher. In this population visceral obesity was associated with metabolic abnormalities, such as higher LDL-cholesterol, triglyceride, glucose, and blood pressure and lower HDL-cholesterol. Thus we determined the incidence of metabolic syndrome and each metabolic abnormality in the Japanese general population in 2000 and found an association of visceral obesity with metabolic abnormalities. Intervention to reduce the incidence of metabolic syndrome in Japan is necessary to reduce the risk of cardiovascular disease.

Adult↗
PubMed2005

Identification of novel steroid target genes through the combination of bioinformatics and functional analysis of hormone response elements.

Steroid hormone receptors including androgen receptor (AR), glucocorticoid receptor (GR), progesterone receptor (PR), and mineralocorticoid receptor (MR) recognize and bind to identical consensus hormone response elements (HREs), which consist of two hexameric half-sites (5'-AGAACA-3') arranged as inverted repeats with a 3-bp spacer. Although only a few near-consensus HRE sequences have been identified in the transcriptional regulatory regions of known steroid target genes, it has been unclear whether the exact consensus sequences function as bona fide HREs in vivo. A genome-wide in silico screening of palindromic HREs identified 565 exact consensus sequences in human genome (NCBI 35 assembly). In this study, of 565 exact consensus elements, functional in vivo receptor binding was evaluated regarding 26 sequences located within 10 kb upstream to the 5' end of annotated genes through chromatin immunoprecipitation (ChIP) assay using cells endogenously expressing steroid hormone receptors. Hormone responsiveness of proximal gene expression was examined through quantitative RT-PCR. As far as performing ChIP assay for AR, GR, and PR, 14 of 26 elements significantly recruited at least one of the receptors by hormone treatment (>2-fold enrichment versus vehicle). In terms of gene expression in the vicinity of the above 14 functional perfect HREs, four genes were upregulated by >2-fold with hormone treatment. The present data suggest that the combination of bioinformatics analysis and quantitative experimental evaluation is useful to identify novel functional HREs that may contribute to the transcriptional regulation of steroid target genes.

Cell Line, Tumor↗
PubMed2005

Estrogen-responsive finger protein as a new potential biomarker for breast cancer.

PURPOSE: Estrogen-responsive finger protein (Efp) is a member of RING finger-B box-Coiled Coil family and is also a downstream target of estrogen receptor alpha. Previously, Efp was shown to mediate estrogen-induced cell growth, which suggests possible involvement in the development of human breast carcinomas. In this study, we examined expression of Efp in breast carcinoma tissues and correlated these findings with various clinicopathologic variables. EXPERIMENTAL DESIGN: Thirty frozen specimens of breast carcinomas were used for immunohistochemistry and laser capture microdissection/real-time PCR of Efp. Immunohistochemistry for Efp was also done in 151 breast carcinoma specimens fixed with formalin and embedded in paraffin wax. RESULTS: Efp immunoreactivity was detected in breast carcinoma cells and was significantly associated with the mRNA level (n = 30). Efp immunoreactivity was positively associated with lymph node status or estrogen receptor alpha status and negatively correlated with histologic grade or 14-3-3sigma immunoreactivity (n = 151). Moreover, Efp immunoreactivity was significantly correlated with poor prognosis of breast cancer patients, and multivariate analyses of disease-free survival and overall survival for 151 breast cancer patients showed that Efp immunoreactivity was the independent marker. CONCLUSIONS: Our data suggest that Efp immunoreactivity is a significant prognostic factor in breast cancer patients. These findings may account for an oncogenic role of Efp in the tumor progression of breast carcinoma.

14-3-3 Proteins↗
PubMed2005

VEGF-A and FGF-2 synergistically promote neoangiogenesis through enhancement of endogenous PDGF-B-PDGFRbeta signaling.

Combined stimulation with VEGF-A, FGF-2, or PDGF-BB has emerged as a potent strategy for therapeutic angiogenesis, although the mechanisms underlying the synergism of these factors are not well understood. In the present study, we investigated the mechanism of synergism between VEGF-A and FGF-2 by using Matrigel plug assay in vivo and embryonic stem cell (ESC)-derived VEGF receptor 2 (VEGFR2)-positive cells in vitro. Experiments in vitro revealed that, in addition to having direct mitogenic effects, these molecules enhance intercellular PDGF-B signaling in a cell-type specific manner: VEGF-A enhances endothelial PDGF-B expression, whereas FGF-2 enhances mural PDGF receptor beta (PDGFRbeta) expression. Co-stimulation with VEGF-A and FGF-2 caused significant mural cell recruitment in vitro and formation of functional neovasculature in vivo, compared with single-agent stimulation. These effects were abrogated not only by anti-PDGFRbeta neutralizing antibody, but also by exogenous PDGF-BB, which could overwhelm the endogenous PDGF-BB distribution. These findings indicated the importance of preservation of the periendothelial PDGF-BB gradient. Thus, we demonstrated that the directional enhancement of endogenous PDGF-B-PDGFRbeta signaling is indispensable for the synergistic effect of VEGF-A and FGF-2 on neoangiogenesis in adults. The findings provide insights into the mechanisms underlying the effects of co-stimulation by growth factors, which could lead to rational design of therapeutic angiogenic strategies.

Animals↗
PubMed2005

Tyrosine phosphorylation of paxillin affects the metastatic potential of human osteosarcoma.

To acquire information on signal alteration corresponding to the changes in metastatic potential, we analysed protein tyrosine phosphorylation of low- and high-metastatic human osteosarcoma HuO9 sublines, which were recently established as the first metastatic model of human osteosarcoma. Tyrosine phosphorylation of proteins around 60, 70, and 120-130 kDa was enhanced in high-metastatic sublines. Among these proteins, the protein around 70 kDa, which was most remarkably phosphorylated, was identified as paxillin, a scaffold protein in integrin signaling. Activity of Src family kinase correlated well with metastatic potential, and a Src family kinase inhibitor, PP2, not only abolished tyrosine phosphorylation of paxillin but also impaired the motility of high-metastatic sublines. The expression of paxillin was also elevated in high-metastatic sublines, and knocking down of paxillin expression by RNAi method resulted in attenuated motility of high-metastatic cells. We also demonstrated that the phosphorylated form of paxillin is essential for the migration-promoting effect in human osteosarcoma. These findings suggest that enhanced activity of Src family kinases and overexpression of paxillin synergistically contribute to the high metastatic potential of human osteosarcoma through the hyperphosphorylation of paxillin.

Animals↗
PubMed2005

Estrogen receptor-binding fragment-associated antigen 9 is a tumor-promoting and prognostic factor for renal cell carcinoma.

The estrogen receptor-binding fragment-associated antigen 9 (EBAG9) has been identified as a primary estrogen-responsive gene in human breast cancer MCF7 cells. A high expression of EBAG9 has been observed in invasive breast cancer and advanced prostate cancer, suggesting a tumor-promoting role of the protein in malignancies. Here we show that intratumoral (i.t.) administration of small interfering RNA against EBAG9 exerted overt regression of tumors following s.c. implantation of murine renal cell carcinoma (RCC) Renca cells. Overexpression of EBAG9 did not promote the proliferation of culture Renca cells; however, the inoculated Renca cells harboring EBAG9 (Renca-EBAG9) in BALB/c mice grew faster and developed larger tumors compared with Renca cells expressing vector alone (Renca-vector). After renal subcapsular implantation, Renca-EBAG9 tumors significantly enlarged compared with Renca-vector tumors in BALB/c mice, whereas both Renca-EBAG9 and Renca-vector tumors were developed with similar volumes in BALB/c nude mice. No apparent difference was observed in specific cytotoxic T-cell responses against Renca-EBAG9 and Renca-vector cells; nonetheless, the number of infiltrating CD8+ T lymphocytes was decreased in Renca-EBAG9 subcapsular tumors. Furthermore, immunohistochemical study of EBAG9 in 78 human RCC specimens showed that intense and diffuse cytoplasmic immunostaining was observed in 87% of the cases and positive EBAG9 immunoreactivity was closely correlated with poor prognosis of the patients. Multivariate analysis revealed that high EBAG9 expression was an independent prognostic predictor for disease-specific survival (P = 0.0485). Our results suggest that EBAG9 is a crucial regulator of tumor progression and a potential prognostic marker for RCC.

Adult↗
PubMed2005

Hange-koboku-to, a Kampo medicine, modulates cerebral levels of 5-HT (5-hydroxytryptamine), NA (noradrenaline) and DA (dopamine) in mice.

Cerebral monoamine systems play important pathogenic roles in various psychiatric and neurologic diseases, such as depression, anxiety and swallowing disturbance. Hange-koboku-to, a Kampo (Japanese herbal) medicine, has been successfully used for the treatment of these disorders. To elucidate the mechanisms underlying its clinical efficacy for these disorders, the effects of Hange-koboku-to (500 mg/kg, p.o.) on the cerebral monoamine systems were examined. Regional levels of 5-HT (5-hydroxytryptamine), NA (noradrenaline), DA (dopamine) and their metabolites in mouse brain were measured using a high-performance liquid chromatography system. Hange-koboku-to increased the 5-HT and NA levels and decreased 5-HIAA (5-hydroxyindole-3-acetic acid), thus decreasing 5-HT and NA turnover (metabolites/monoamine ratio) in the hypothalamus. The levels of DA, DOPAC (3,4-dihydroxyphenylacetic acid) and HVA (4-hydroxy-3-methoxy-phenylacetic acid) were all increased, resulting in a decreased DA turnover in the striatum. Since decreased 5-HT turnover has been observed after administration of various antidepressants, Hange-koboku-to-mediated reduction of 5-HT turnover may be related to the clinical efficacy of this Kampo medicine on certain psychiatric disorders. Furthermore, the beneficial therapeutic effects of Hange-koboku-to on swallowing disturbance may be related to the increased cerebral DA level brought about by this Kampo medicine.

Administration, Oral↗
PubMed2005

Association of a single nucleotide polymorphism in the lipoxygenase ALOX15 5'-flanking region (-5229G/A) with bone mineral density.

The 12/15-lipoxygenase gene Alox15 has been identified as a susceptibility gene for bone mineral density (BMD) in mice through combined genetic and genomic analyses. Here we studied the association between bone mineral density and an ALOX15 gene single nucleotide polymorphism to assess the potential involvement of the human ALOX15 gene in postmenopausal osteoporosis. Specifically, we examined the association between a single nucleotide polymorphism at -5299G/A in the ALOX15 5'-flanking region with BMD in 319 postmenopausal Japanese women (66.7 +/- 8.9 years, mean +/- SD). We found that subjects bearing at least one variant A allele (GA + AA; n = 273) had significantly lower Z scores for lumbar spine and total body bone mineral density than did subjects with no A allele (GG; n = 46) (lumbar spine, -0.25 +/- 1.34 versus 0.48 +/- 1.70; P = 0.0014; total body, 0.25 +/- 1.01 vs 0.62 +/- 1.11; P = 0.048). These findings suggest that the ALOX15 gene is one of the genetic determinants of BMD in postmenopausal women. Accordingly, this polymorphism could be useful as a genetic marker for predicting the risk of osteoporosis.

Aged↗