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Biomedical subjects

Atsunori Kashiwagi

Publications and source records attributed to Atsunori Kashiwagi.

At least 19 recordsLinked to original sources
PubMed2007

Pulmonary-renal syndrome, diffuse pulmonary hemorrhage and glomerulonephritis, associated with Wegener's granulomatosis effectively treated with early plasma exchange therapy.

We present a case of a 38-year-old Japanese man with Wegener's granulomatosis complicated with pulmonary-renal syndrome, i.e., diffuse pulmonary hemorrhage and rapidly progressive renal glomerulonephritis. As this is a life-threatening condition, we promptly initiated plasma exchange with intravenous methylprednisolone therapy. Diffuse pulmonary hemorrhage and renal failure were markedly improved. This case merits presentation because there are few clinical studies of the treatment of Wegener's granulomatosis with pulmonary-renal syndrome, particularly with pulmonary hemorrhage.

Adult↗
PubMed2006

RBMX is a novel hepatic transcriptional regulator of SREBP-1c gene response to high-fructose diet.

In rodents a high-fructose diet induces metabolic derangements similar to those in metabolic syndrome. Previously we suggested that in mouse liver an unidentified nuclear protein binding to the sterol regulatory element (SRE)-binding protein-1c (SREBP-1c) promoter region plays a key role for the response to high-fructose diet. Here, using MALDI-TOF MASS technique, we identified an X-chromosome-linked RNA binding motif protein (RBMX) as a new candidate molecule. In electrophoretic mobility shift assay, anti-RBMX antibody displaced the bands induced by fructose-feeding. Overexpression or suppression of RBMX on rat hepatoma cells regulated the SREBP-1c promoter activity. RBMX may control SREBP-1c expression in mouse liver in response to high-fructose diet.

Animals↗
PubMed2006

Combinational effect of genes for the renin-angiotensin system in conferring susceptibility to diabetic nephropathy.

To elucidate the role of the renin-angiotensin system (RAS) in diabetic nephropathy, we examined the association between diabetic nephropathy in a large cohort of Japanese type 2 diabetic patients and polymorphisms within the genes that encode angiotensin-converting enzyme (ACE), angiotensinogen (AGT) and angiotensin II receptor type 1 (AGTR1). Single nucleotide polymorphisms (SNPs) within these genes were genotyped using invader assay in 747 nephropathy cases and 557 control subjects. Eight SNPs within the ACE gene were significantly associated with diabetic nephropathy (P<0.05), including five SNPs in almost complete linkage disequilibrium to the insertion/deletion polymorphism in the 16th intron (P=0.01, odds ratio =1.34, 95% CI 1.07-1.69). Three SNPs within the AGT, including M235T and one SNP in the AGTR1, were also significantly associated with nephropathy (M235T P=0.01, odds ratio =0.74, 95% CI 0.59-0.94). In addition, we found that the allelic mRNA expression corresponding to the 235M allele was significantly higher than that for the 235T allele in normal kidney tissues. Furthermore, we found a significant additional effect of these three genes by a step-wise logistic regression analysis (final empirical P value =0.00005). We concluded that RAS gene polymorphisms may contribute to the susceptibility to diabetic nephropathy in type 2 diabetes.

Angiotensinogen↗
PubMed2006

SIRT1 inhibits transforming growth factor beta-induced apoptosis in glomerular mesangial cells via Smad7 deacetylation.

SIRT1, a class III histone deacetylase, is considered a key regulator of cell survival and apoptosis through its interaction with nuclear proteins. In this study, we have examined the likelihood and role of the interaction between SIRT1 and Smad7, which mediates transforming growth factor beta (TGFbeta)-induced apoptosis in renal glomerular mesangial cells. Immunoprecipitation analysis revealed that SIRT1 directly interacts with the N terminus of Smad7. Furthermore, SIRT1 reversed acetyl-transferase (p300)-mediated acetylation of two lysine residues (Lys-64 and -70) on Smad7. In mesangial cells, the Smad7 expression level was reduced by SIRT1 overexpression and increased by SIRT1 knockdown. SIRT1-mediated deacetylation of Smad7 enhanced Smad ubiquitination regulatory factor 1 (Smurf1)-mediated ubiquitin proteasome degradation, which contributed to the low expression of Smad7 in SIRT1-overexpressing mesangial cells. Stimulation by TGFbeta or overexpression of Smad7 induced mesangial cell apoptosis, as assessed by morphological apoptotic changes (nuclear condensation) and biological apoptotic markers (cleavages of caspase3 and poly(ADP-ribose) polymerase). However, TGFbeta failed to induce apoptosis in Smad7 knockdown mesangial cells, indicating that Smad7 mainly mediates TGFbeta-induced apoptosis of mesangial cells. Finally, SIRT1 overexpression attenuated both Smad7- and TGFbeta-induced mesangial cell apoptosis, whereas SIRT1 knockdown enhanced this apoptosis. We have concluded that Smad7 is a new target molecule for SIRT1 and SIRT1 attenuates TGFbeta-induced mesangial cell apoptosis through acceleration of Smad7 degradation. Our results suggest that up-regulation of SIRT1 deacetylase activity is a potentially useful therapeutic strategy for prevention of TGFbeta-related kidney disease through its effect on cell survival.

Animals↗
PubMed2006

Transcription factor activating enhancer-binding protein-2beta. A negative regulator of adiponectin gene expression.

We previously reported the association between the activating enhancer-binding protein-2beta (AP-2beta) transcription factor gene and type 2 diabetes. This gene is preferentially expressed in adipose tissue, and subjects with the disease-susceptible allele of AP-2beta showed stronger expression in adipose tissue than those without the susceptible allele. Furthermore, overexpression of AP-2beta leads to lipid accumulation by enhancing glucose transport and inducing insulin resistance in 3T3-L1 adipocytes. In this study we demonstrated that overexpression of AP-2beta in 3T3-L1 adipocytes decreased the expression and secretion of adiponectin and increased those of interleukin-6 (IL-6). Interestingly, the effects of AP-2beta on the expressions of adiponectin and IL-6 and the mechanisms by which AP-2beta modulated their expressions were different. We found that the promoter activity of adiponectin gene was inhibited by AP-2beta overexpression and enhanced by knockdown of endogenous AP-2beta, whereas IL-6 was unaffected. Electrophoretic mobility shift assays revealed the existence of putative responsive elements for AP-2beta and NF-YA in human and mouse adiponectin promoter regions, and mutation of this AP-2beta binding site abolished the inhibitory effect of AP-2beta. Furthermore, chromatin immunoprecipitation assays demonstrated that AP-2beta and NF-YA competitively bind to the same region of the adiponectin promoter. Our results clearly demonstrated that AP-2beta directly inhibits adiponectin gene expression by displacing NF-YA and binding to its promoter. We conclude that AP-2beta might modulate the expression of adiponectin by directly inhibiting its transcriptional activity.

3T3-L1 Cells↗
PubMed2006

MafA differentiates rat intestinal cells into insulin-producing cells.

Recent studies have suggested that basic leucine zipper transcription factor MafA has a crucial role in pancreatic beta-cell-specific insulin gene transcription. Thus, we investigated whether MafA overexpression in the intestine induces insulin production in small-intestinal epithelial cells in vivo. Recombinant adenovirus containing MafA gene (Ad-MafA) was prepared and administered orally to streptozocin-treated diabetic rats. Insulin gene expression was observed in the intestine by RT-PCR analysis, and then insulin protein was detected by immunohistochemical analysis after Ad-MafA administration. Furthermore, MafA overexpression in the intestine increased plasma insulin levels and ameliorated hyperglycemia. These results indicate that MafA overexpression in the intestine induces intestinal epithelial cells newly to produce and release insulin.

Animals↗
PubMed2006

Alcohol consumption and coronary artery calcium in middle-aged Japanese men.

Epidemiologic studies have investigated the relation between alcohol intake and coronary calcification, with controversial results. Furthermore, the influence of heavy drinking has not been well elucidated. In the present study, a random sample of community-based Japanese men aged 40 to 49 years without a history of cardiovascular disease (n=245) were examined for coronary artery calcium (CAC) determined by electron-beam computed tomography and drinking status. There was a J-shaped association between alcohol intake and CAC. There was an increase of CAC in heavy drinkers (>or=46 g/day), and participants who were drinking>or=69 g/day showed a significant increase in CAC compared with never drinkers after adjusting for other cardiovascular risk factors.

Adult↗
PubMed2006

Systemic cholesterol embolization syndrome associated with myeloperoxidase-anti-neutrophil cytoplasmic antibody.

A 75-year-old man was transferred to our department because of development of severe renal impairment after coronary artery bypass grafting. Hemodialysis was initiated for postsurgical oliguria and lung congestion. On transfer, he showed systemic purpura rashes and diffuse blue mottlings on his toes with marked eosinophilia and an elevated level of C-reactive protein. Cutaneous biopsy revealed cholesterol crystal embolism and leukocytoclastic vasculitis in dermal arterioles. Myeloperoxidase-anti-neutrophil cytoplasmic antibody titer was increased. Upon oral corticosteroid therapy following intravenous pulse steroid therapy, the purpura dramatically diminished, renal function improved, and hemodialysis was discontinued. Active treatment with corticosteroids may be effective for cholesterol embolization syndrome, particularly when clinical and laboratory manifestations mimic systemic vasculitis.

Aged↗