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Masakazu Haneda

Publications and source records attributed to Masakazu Haneda.

At least 19 recordsLinked to original sources
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

Repeated administrations of concanavalin A induce Th1 to Th2 cytokine shift and tolerance against liver injury in mice.

The intravenous injection of concanavalin A (Con A) activates T cells and induces cytokine dependent liver injury in mice. However, the effect of repeated administrations of Con A has not been fully investigated. Female BALB/c mice were intravenously injected with Con A (20mg/kg) or saline once a week for six times. Mice were rechallenged with Con A 17 days after repeated administrations of Con A. Repeated Con A administrations elicited a sustained inhibition of rechallenged-Con A-induced liver injury. Plasma TNF-alpha and IFN-gamma levels after rechallenge of Con A were decreased compared with that of repeated saline treatments. By contrast, plasma IL-4 and IL-10 levels after rechallenge of Con A were increased. In spleen cells prepared from repeated Con A treated mice, the production of TNF-alpha and IFN-gamma 24h after co-incubation with Con A decreased, and that of IL-4 and IL-10 increased. In naive mice, plasma ALT level after Con A injection was decreased by the transfer of spleen cells prepared from the repeated Con A treated mice. The repeated administrations of Con A elicited Th1 to Th2 cytokine shift and the tolerant state against the Con A-induced liver injury in mice.

Journal Article↗
PubMed2006

Regression of cardiac hypertrophy in type 2 diabetes with hypertension by candesartan.

This study was designed to compare the effect of candesartan on cardiac left ventricular mass in Japanese patients with that of amlodipine. A total of 40 type 2 diabetic patients with hypertension and left ventricular hypertrophy (LVH) were randomly assigned to receive candesartan (n=20) or amlodipine (n=20). The two treatments when administered for 6 months significantly reduced systolic and diastolic blood pressures (BPs) to a comparable extent. Notably, candesartan significantly reduced left ventricular mass index (LVMI: from 131.5+/-4.5 to 112.1+/-5.9g/m(2), P=0.0009, M+/-S.E.M.), LV posterior wall thickness (PWTd: from 10.3+/-0.3 to 9.1+/-0.3mm, P=0.0052) and interventricular septal thickness (IVSTd: from 10.7+/-0.4 to 9.3+/-0.4mm, P=0.0019) as determined by echocardiography in diastole, but amlodipine treatment did not. LVMI, PWTd and IVSTd were decreased more significantly by the treatment with candesartan than by that with amlodipine (P=0.020, 0.031 and 0.043). The present study thus revealed that candesartan effectively induced regression of LVH in type 2 diabetic patients with hypertension due to effects beyond reduction in BP.

Adult↗
PubMed2006

Fucoidan prevents concanavalin A-induced liver injury through induction of endogenous IL-10 in mice.

Fucoidan is a complex of sulfated polysaccharides derived from non-mammalian origin such as marine brown algae and induces cytokine expression. We investigated the effect of fucoidan on concanavalin A (Con A)-induced liver injury in mice. Liver injury was induced by an intravenous injection of Con A (18.5mg/kg). Various doses of fucoidan (1-30mg/kg) were intravenously administered 30min before Con A injection. The plasma alanine aminotransferase (ALT) and several cytokines levels were determined, and hepatic histological changes were also assessed. The effect of fucoidan administration by itself on induction of interleukin (IL)-10 in plasma and liver tissue was investigated. Con A administration induced an elevation of plasma ALT level, and fucoidan administration dose-dependently prevented the Con A-induced elevation of plasma ALT. Con A administration increased plasma TNF-alpha and IFN-gamma levels, and fucoidan pretreatment significantly inhibited these alterations and increased plasma IL-10 level. The inhibitory effect of fucoidan on Con A-induced liver injury and production of proinflammatory cytokines were reversed by anti-mouse IL-10 antibody pretreatment. Fucoidan induced the IL-10 production in plasma and liver tissue. These findings suggest that fucoidan prevents Con A-induced liver injury by mediating the endogenous IL-10 production and the inhibition of proinflammatory cytokine in mice.

Journal Article↗
PubMed2006

Silent information regulator 2 (SIRT1) attenuates oxidative stress-induced mesangial cell apoptosis via p53 deacetylation.

Oxidative stress-induced apoptosis of renal glomerular cells is an important factor for the development of various kidney diseases. Identification of molecules that modulate this process could lead to the development of new strategies for preventing kidney diseases. In this study, we evaluated whether mammalian silent information regulator 2 (SIRT1), which has been recently identified as a cell survival factor countering various stressors, is a key regulator of oxidative stress-induced mesangial cell apoptosis. Morphological features of apoptotic cell death (nuclear condensation) and the expression of biochemical proapoptotic markers [cleavages of caspase-3 and poly (ADP-ribose) polymerase (PARP)] were assessed in murine mesangial cells (MMCs) exposed to hydrogen peroxide (H(2)O(2)). H(2)O(2) increased mesangial cell apoptosis, predominantly through p53 activation by acetylation, which is a posttranscriptional modification for p53 activation. H(2)O(2)-induced apoptosis was significantly attenuated in SIRT1-overexpressing MMCs, but enhanced in SIRT1-knockdown MMCs. Although SIRT1 did not affect H(2)O(2)-mediated phosphorylation of mitogen-activated protein (MAP) kinase, it interacted with p53 and inhibited H(2)O(2)-mediated p53 acetylation but not phosphorylation in MMCs. Our results indicate that SIRT1 can prevent oxidative stress-induced apoptosis through p53 deacetylation in mesangial cells. Upregulation of SIRT1 may provide a new strategy for preventing kidney glomerular diseases.

Acetylation↗
PubMed2006

N-acetyl-seryl-aspartyl-lysyl-proline inhibits DNA synthesis in human mesangial cells via up-regulation of cell cycle modulators.

N-Acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) was originally reported as a natural inhibitor of the proliferation of stem cells. To elucidate whether Ac-SDKP inhibits the proliferation of human mesangial cells, we examined the effect of Ac-SDKP on fetal calf serum (FCS)- or platelet-derived growth factor (PDGF)-BB-induced DNA synthesis and a cell proliferation. Ac-SDKP inhibited PDGF-BB- or FCS-induced DNA synthesis without cellular toxicity. The protein expression of p53 and p27kip1 was significantly increased by Ac-SDKP. Ac-SDKP also up-regulated the PDGF-BB-stimulated expression of p21cip1 and suppressed PDGF-BB-induced cyclin D1 expression. In p53 knock-out human mesangial cells made with small interference RNA, the protein expression of p21cip1 and p27kip1 was also decreased and the inhibitory effect of Ac-SDKP on mesangial proliferation was completely abolished. Ac-SDKP increased the stability of p53 protein as demonstrated by pulse-chase experiment. These results suggest that p53 is the key mediator of Ac-SDKP-induced inhibition of DNA synthesis through the up-regulation of cell cycle modulators, highlighting a potential effect of Ac-SDKP on various progressive renal diseases.

Cell Cycle↗
PubMed2006

N-acetyl-seryl-aspartyl-lysyl-proline ameliorates the progression of renal dysfunction and fibrosis in WKY rats with established anti-glomerular basement membrane nephritis.

N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP), which is hydrolyzed by angiotensin-converting enzyme, is a natural regulator of hematopoiesis. Here it is shown that Ac-SDKP inhibits TGF-beta action in mesangial cells. Because TGF-beta is thought to play a pivotal role in the development and progression of glomerulonephritis, the therapeutic effects of Ac-SDKP on an established model of renal dysfunction and histologic alteration in Wistar-Kyoto rats with anti-glomerular basement membrane nephritis was examined. Fourteen days after the induction of anti-glomerular basement membrane nephritis, the rats were treated subcutaneously with Ac-SDKP at a dose of 1 mg/kg per d for 4 wk. Treatment with Ac-SDKP significantly improved proteinuria and renal dysfunction, including increased plasma blood urea nitrogen and creatinine levels and decreased creatinine clearance. Histologic examination showed severe glomerulosclerosis and interstitial fibrosis in the vehicle-treated rats, whereas these histologic injuries were significantly ameliorated in rats that were treated with Ac-SDKP. The histologic improvements were accompanied by the suppression of gene and protein expression of fibronectin, interstitial collagen, and TGF-beta1 in the nephritic kidney. Furthermore, treatment with Ac-SDKP resulted in the inhibition of Smad2 phosphorylation, an increase in Smad7 expression in the kidney, and reduction of macrophage accumulation into the glomeruli and tubulointerstitium in nephritic rats. In conclusion, Ac-SDKP significantly ameliorated the progression of renal dysfunction and fibrosis even after the establishment of nephritis. The inhibitory effect of Ac-SDKP was mediated in part by the inhibition of TGF-beta/Smad signal transduction and the inflammatory response. These findings suggest that Ac-SDKP treatment may be a novel and useful therapeutic strategy for the treatment of progressive renal diseases.

Analysis of Variance↗
PubMed2006

Inhibitory effect of angiotensin II receptor antagonist on hepatic stellate cell activation in non-alcoholic steatohepatitis.

AIM: To investigate the efficacy of angiotensin II receptor antagonist on hepatic stellate cells (HSCs) activation in the patients with non-alcoholic steatohepatitis (NASH). METHODS: Seven patients with NASH were prescribed losartan, a selective angiotensin II type 1 receptor antagonist (50 mg/d) for 48 wk. Liver biopsies were performed both at the entry and end of the study in all patients. Quiescent and activated HSCs were identified by double immunostaining using anti-p75 and -smooth muscle actin antibodies, and the number of each phenotype was counted. Similarly, the liver specimens obtained from the eight patients with non-alcoholic fatty liver (NAFL) were also examined as controls. RESULTS: In NASH hepatic tissues, activated HSCs were dominantly distributed as compared with those in NAFL. The 48-wk losartan treatment induced a remarkable decrease in activated HSCs and a mild increase in quiescent phenotypes. CONCLUSION: Our data suggest the crucial involvement of HSCs in anti-fibrotic effect of angiotensin II receptor antagonist on patients with NASH.

Adult↗
PubMed2006

Enhanced sodium sensitivity and disturbed circadian rhythm of blood pressure in essential hypertension.

OBJECTIVE: To assess whether an association between sodium-sensitive hypertension and metabolic syndrome exists; and whether, in patients with metabolic syndrome, the nocturnal fall of blood pressure decreases and salt restriction affects the circadian blood pressure rhythm. METHODS: Japanese patients with essential hypertension, who were treated without any antihypertensive agent, were maintained on a high-sodium diet and a low-sodium diet for 1 week each. On the last day of each diet, the 24-h blood pressures were measured. A diagnosis of metabolic syndrome was made according to the International Diabetes Foundation definition RESULTS: Among the 56 patients with essential hypertension, 15 patients were complicated with metabolic syndrome while 41 patients were not. The nocturnal blood pressure fall was significant in patients without metabolic syndrome, while it was not so in patients with metabolic syndrome. Only in patients with metabolic syndrome was the nocturnal blood pressure fall enhanced by sodium restriction. The prevalence of sodium-sensitive hypertension in patients with metabolic syndrome was significantly higher than in those without metabolic syndrome (70.6 versus 36.0%, respectively; P = 0.017). A multiple logistic regression analysis revealed central obesity to be an independent risk factor for sodium-sensitive hypertension (odds ratio, 1.41; 95% confidence interval, 1.04-1.91). CONCLUSIONS: In patients with essential hypertension, an inter-relationship exists among metabolic syndrome, enhanced sodium sensitivity of the blood pressure and non-dipping. The elevated risk of cardiovascular diseases in patients with metabolic syndrome may be related to sodium-sensitive hypertension and non-dipping.

Adult↗
PubMed2006

Chenodeoxycholic acid and taurochenodexycholic acid induce anti-apoptotic cIAP-1 expression in human hepatocytes.

BACKGROUND AND AIMS: Increased concentration of endogenous bile acids in the liver correlates with clinical features of cholestatic liver diseases. Recently, it was reported that non-toxic hydrophobic bile acid activated a survival signaling pathway via phosphatidylinositol 3 (PI3) kinase in hepatocytes. However, whether bile acid induces inhibitors of apoptosis protein (IAPs) directly in human hepatocytes remains unknown. This study investigated effects of bile acids on cIAP-1, cIAP-2 and XIAP expression in hepatocytes. METHODS: Human fetal hepatocytes and HepG2 cells were treated with free or conjugated chenodeoxycholic acid (CDCA) or ursodeoxycholic acid in the presence or absence of several inhibitors. Reverse transcriptase-polymerase chain reaction and Western blot analyses were performed for mRNA and protein expressions, respectively, of IAPs. Luciferase assay was used to investigate transcriptional activity of nuclear factor (NF)-kappaB. RESULTS: Chenodeoxycholic acid up-regulated both mRNA and protein expressions of cIAP-1. In particular, taurochenodeoxycholic acid (TCDCA), but not glycochenodeoxycholic acid (GCDCA), induced cIAP-1 mRNA expression. In contrast, cIAP-2 and XIAP mRNA expressions were not influenced by CDCA. Moreover, CDCA-induced cIAP-1 mRNA expression was inhibited completely by calphostin C and SB203580, but not by wortmannin. Luciferase assay showed that CDCA and TCDCA activated NF-kappaB-driven transcriptional activity. CONCLUSION: It was shown that CDCA induced cIAP-1 expression in hepatocytes through protein kinase C- and p38 mitogen-activated protein kinase-mediated pathway. Especially, TCDCA, but not GCDCA, increased cIAP-1 mRNA expression and NF-kappaB-regulated transcriptional activity. Therefore, it is suggested that CDCA and TCDCA themselves have an inhibitory potential against apoptosis through the cIAP-1-survival signaling pathway, in addition to PI3 kinase-dependent pathway.

Apoptosis↗
PubMed2006

Combination of multiple genetic risk factors is synergistically associated with carotid atherosclerosis in Japanese subjects with type 2 diabetes.

OBJECTIVE: Several genetic risk factors, such as single nucleotide polymorphisms (SNPs), in candidate genes have been reported to be responsible for intima-media thickness (IMT), which is one of the surrogate end points of cardiovascular events. However, the synergistic effects of SNPs have not been evaluated in detail. RESEARCH DESIGN AND METHODS: We measured the average IMT of the common and internal carotid artery in Japanese type 2 diabetic patients (n = 690) (>50 years old) using ultrasonography. We also determined their genotypes regarding 106 SNPs in candidate genes responsible for cardiovascular diseases. Among the 106 SNPs, we selected 40 common (frequency of minor allele >/=10%) SNPs. We compared the average IMT of subjects with and without any pairs of four genotypes selected from the 40 common SNPs. RESULTS: The combination of methylen-tetrahydrofolate reductase 677 TT genotype and lymphotoxin-alpha (LTA) 252 GG genotype and that of ACE DD genotype and LTA 252 GG genotype were evaluated as responsible for a statistically significant (P = 2.7 x 10(-9) and 3.5 x 10(-6), respectively) increase in average IMT (mean [+/-SD] 1.54 +/- 0.60 and 1.43 +/- 0.58 mm, respectively) compared with those of the subjects without these combinations (1.04 +/- 0.34 and 1.04 +/- 0.34 mm, respectively). No single genotype was shown to be responsible for the statistically significant difference in average IMT after Bonferroni's multiple comparison procedure. CONCLUSIONS: The present analysis demonstrates an approach to evaluate combinations of multiple genetic risk factors that are synergistically associated with carotid atherosclerosis.

Aged↗
PubMed2006

Polymorphisms of the protein kinase C-beta gene (PRKCB1) accelerate kidney disease in type 2 diabetes without overt proteinuria.

OBJECTIVE: We investigated the contribution of PKC-beta gene (PRKCB1) polymorphisms to diabetic kidney disease in a prospective observational follow-up study. RESEARCH DESIGN AND METHODS: A total of 364 Japanese subjects with type 2 diabetes without overt proteinuria were enrolled during 1996-1998 and followed until 2004. Five single nucleotide polymorphisms (-1504C/T, -546C/G, -348A/G, -278C/T, and -238C/G) in the promoter region of PRKCB1 were genotyped. The end points were transition from stage to stage of diabetic nephropathy as a time-to-event outcome and the annual decline rate of estimated glomerular filtration rate (eGFR) as a slope-based outcome. RESULTS: During the study (median 6 years), 34 of 364 subjects (9.3%) progressed. Kaplan-Meier estimation revealed that subjects with both T allele at -1054 C/T and G allele at -546 C/G polymorphisms frequently showed transition to advanced stages of diabetic nephropathy (P = 0.015). The annual change rate in eGFR in the subjects with both alleles was also significantly higher than in others (-2.96 +/- 0.62 vs. -1.63 +/- 0.15 ml/min per 1.73 m(2)/year, P = 0.02). The estimated frequency of this risk T-G haplotype was significantly higher in the progressors who showed transition to advanced nephropathy stages (12%) than in the nonprogressors (5%) (odds ratio 2.3 [95% CI 1.0-5.2]), and it was also higher in those with accelerated decline of the Delta eGFR (> or =3 ml/min per 1.73 m(2)/year) than in those without (2.1 [1.1-3.9]). CONCLUSIONS: Our study indicates that PRKCB1 is a predictor for worsening of kidney disease in Japanese subjects with type 2 diabetes.

Albuminuria↗
PubMed2006

[Clinical utility of angiotensin II receptor antagonist].

Non-alcoholic steatohepatitis (NASH) can potentially progress to liver cirrhosis and hepatocellular carcinoma. The causes of this disease are not well defined, and although several therapies have been tried, the optimal treatment has not been established. Recently, a role for angiotensin II in insulin resistance, oxidative stress and hepatic stellate cell activation has been reported. We treated patients who had NASH and hypertension with losartan, an angiotensin II receptor antagonist for 48 weeks. The losartan treatment improved hepatic necroinflammation and fibrosis in NASH patients. Moreover, a disappearance of iron deposition in hepatocytes, and a decrease in activated hepatic stellate cells were detected after treatment. Our results suggest the therapeutic efficacy of angiotensin II receptor antagonist in patients with NASH.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2005

[Diabetes mellitus].

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Diabetic Nephropathies↗
PubMed2005

Protective effect of central thyrotropin-releasing hormone analog on cerulein-induced acute pancreatitis in rats.

Central neuropeptides play a role in many physiological functions through the autonomic nervous system. We have recently demonstrated that central injection of a thyrotropin-releasing hormone (TRH) analog increases pancreatic blood flow through vagal and nitric oxide-dependent pathways. In this study, the central effect of a TRH analog on experimental acute pancreatitis was investigated in rats. Acute pancreatitis was induced by two intraperitoneal injections of cerulein (40 microg/kg) at 1-h interval. Either stable TRH analog, RX 77368 (5-100 ng), or saline was injected intracisternally 15 min before the first cerulein injection under ether anesthesia. Serum amylase level was measured before and 5 h after the first cerulein injection. Pancreatic wet/dry weight ratio and histological changes were also evaluated. Intracisternal TRH analog inhibited cerulean-induced elevation of serum amylase level, increase in pancreatic wet/dry weight ratio and pancreatic histological changes, such as interstitial edema, inflammation and vacuolization. The pancreatic cytoprotection induced by central TRH analog was abolished by subdiaphragmatic vagotomy and N(G)-nitro-L-arginine-methyl ester (L-NAME), but not by 6-hydroxydopamine (6-OHDA). Intravenous administration of the TRH analog did not influence cerulein-induced acute pancreatitis. These results indicate that the TRH analog acts in the central nervous system to protect against acute pancreatitis through vagal and nitric oxide-dependent pathways.

Adrenergic Agents↗
PubMed2005

A case of type 2 diabetes with a large abscess of the gastric wall successfully treated with a glycemic control and systemic antibiotics.

A case of type 2 diabetic patient, a 67-year-old woman, with a large abscess of the gastric wall which seemed to be a primary lesion is described for the first time. Fortunately, patient was successfully treated with both the maintenance of a good glycemic control and systemic antibiotics without laparotomy or drainage. Thus, a tight glycemic control and awareness of this disease should be reemphasized, and this may improve the prognosis of this rare and fatal one, even a poorly-controlled diabetes.

Abdominal Abscess↗
PubMed2005

Macrophage inflammatory protein-1alpha plays a crucial role in concanavalin A-induced liver injury through induction of proinflammatory cytokines in mice.

BACKGROUND/AIMS: : The chemokines play roles in the development of immune mediated liver diseases. In this study, we investigate the involvement of macrophage inflammatory protein-1alpha (MIP-1alpha), one of the CC chemokines in concanavalin A (Con A)-induced liver injury in mice. METHODS: : Liver injury was induced by intravenous injection of Con A. Anti-mouse MIP-1alpha antibody, recombinant murine-MIP-1alpha and gadolinium chloride (GdCl(3)) were administrated prior to Con A injection. Plasma alanine aminotransferase (ALT), MIP-1alpha, tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) levels were determined and histological assessment of the liver was performed. RESULTS: : Plasma MIP-1alpha level was elevated after Con A injection. The elevated plasma ALT level, mortality rate and histological change after Con A injection were inhibited by anti-MIP-1alpha antibody pretreatment. The elevated plasma ALT level after Con A injection was further enhanced by recombinant murine-MIP-1alpha. The elevated plasma TNF-alpha and IFN-gamma levels after Con A injection were inhibited by anti-MIP-1alpha antibody, and enhanced by recombinant murine-MIP-1alpha. GdCl(3) pretreatment inhibited the elevated plasma MIP-1alpha and ALT levels. CONCLUSIONS: : These findings suggest that MIP-1alpha is produced from Kupffer cells after Con A injection, and this CC chemokine plays a crucial role in Con A-induced liver injury through induction of proinflammatory cytokines.

Journal Article↗