蛋白激酶C同工酶在糖尿病肾病肾小球的表达

目的：探讨糖尿病肾病（DN）发病过程中肾小球蛋白激酶C（PKC）同工酶的表达变化及其与DN发生，发展的关系。方法：将实验随机分为正常对照组及STZ－DM模型组，在模型成功后2周，4周和12周，采用免疫组织化学方法检测肾小球PKC同工酶的表达变化情况，结果：在肾小球内，PKCα在DM发病2周，4周，12周时表达显著上升；PKCβ1，PKCⅡ在DM发病2周时表达明显下降，4周，12周时逐渐上升，PKCε的表达无显著性变化。结论：在DN发病过程中的不同阶段，PKC各同工酶在肾小球内的表达变化不同，对DN的发生，发展也有着不同的调控效应。     

糖尿病肾病发病过程中肾小球蛋白激酶C活性变化的研究

随着分子生物学及其相关技术的应用，人们发现众多血管活性物质和细胞因子在糖尿病肾病的发生与发展中起着关键性的作用。这些物质的共同信号传导途径或作用往往通过蛋白激酶Ｃ（ｐｒｏｔｅｉｎ ｋｉｎａｓｅ Ｃ， ＰＫＣ）介导。我们利用γ－３２ＰＡＴＰ底物磷酸化的方法，探讨糖尿病肾病发病过程的不同阶段肾小球ＰＫＣ活性变化规律。 一、材料与方法 １．糖尿病实验模型的制备和分组：取体重 １５０～１７０ ｇ ＳＤ系雄性大鼠９６只，随机分为正常对照２周、４周、１２周组，糖尿病大鼠２周、４周、１２周组，共６组，每组各１６只。经…     

蛋白激酶C与糖尿病肾病

糖尿病肾病（ＤＮ）是导致慢性肾功能不全的重要原因之一，其发病机制尚未完全明确。近年来高糖诱导蛋白激酶Ｃ（ＰＫＣ）信号转导通路激活并促进ＤＮ发生、发展的研究倍受关注。本文综述了糖尿病肾脏ＰＫＣ活化的机制及ＰＫＣ活化对肾脏功能、结构的影响，说明ＰＫＣ与ＤＮ密切相关，ＰＫＣ抑制剂的使用为ＤＮ防治开辟了新途径     

蛋白激酶C与糖尿病肾病

糖尿病肾病（diabeticnophropathy，DN）早期表现为肾脏肥大、肾小球和肾小管基底膜增厚及肾小球内高灌注、高跨膜压，如果没有得到有效地缓解，可逐渐发展为肾小球细胞外基质（ECM）进行性积聚，最终发展为终末期肾功能衰竭，是糖尿病患者最主要的死亡原因之一。门。随着分子生物学及其相关技术的普及，DN的发病机制已逐渐为人们所熟知，已知众多血管活性物质和细胞因子在其中起着关键性作用。这些物质的共同信号传导途径或其作用往往通过蛋白激酶（ploteinhin856C，pKC）介导［Zj，临床和实验研究均表明抑制PKC的活性能延缓甚至逆转…     

蛋白激酶C激活在高糖诱导肾系膜细胞中的作用

目的：探讨高糖对系膜细胞蛋白激酶C（PKC）活性的影响及PKC在系膜细胞增殖、细胞外基质积聚中的作用。方法：采用大鼠系膜细胞进行体外培养,高糖作为激动剂,佛波酯（PMA）作为PKC抑制剂,甘露醇作为渗透压对照,用液闪仪测定PKC活性,^3H-TdR渗入法检测细胞增殖,ELISA法测定培养上清中纤维连接蛋白（FN）含量。结果：高糖可增加系膜细胞颗粒部分PKC活性、抑制细胞增殖、促进FN分泌,且与渗透压无关。抑制PKC后,可阻止高糖诱导的FN分泌。结论：高糖可激活系膜细胞PKC,促进细胞外基质积聚和糖尿病肾症的发生。     

糖尿病大鼠早期肾小球蛋白激酶C活性变化

近年来,有关细胞内信息传导与细胞功能调节在糖尿病并发症的研究中越来越引起人们的重视。二酰基甘油（ＤＡＧ）和蛋白激酶Ｃ（ＰＫＣ）是细胞内重要的信息传导系统［１］,本研究中,我们旨在利用ＡＴＰ底物磷酸化的方法,检测糖尿病大鼠早期肾小球ＰＫＣ活性变化,以探讨肾小球ＰＫＣ的变化在肾小球高滤过和肾小球超微结构改变中所起的作用。 一、材料和方法 １．实验动物：体重２４０～２６０ｇ之间雄性Ｗｉｓｔａｒ大鼠４０只（山东大学实验动物中心提供）,随机分为正常对照组和糖尿病组,每组２０只,单只分笼饲以蛋白含量为２１％标…     

蛋白激酶C与糖尿病肾病

糖尿病肾病是导致慢性肾功能不全的重要原因之一，其发病机制尚未完全明确。近年来高糖诱导蛋白激酶信号转导通路激活并促进ＤＮ发生，发展的研究倍受关注。     

蛋白激酶C与糖尿病肾病

众所周知,蛋白激酶C（protein kinase C,PKC）参与信号转导途径、细胞增殖、分化和凋亡,但其在肾脏疾病中的作用尚未完全阐明。正常肾组织中可见多种PKC同工酶。当肾脏出现病变时部分PKC激活或缺失而发生表达的改变,如高糖使1,2-二酯酰甘油（DAG）水平或PKCβ升高,引起肾脏大血管和微血管病变,从而导致糖尿病肾病、IgA肾病等疾病的发生。[第一段]     

胰岛素及卡托普利对糖尿病大鼠肾小球蛋白激酶C活性的影响

糖尿病肾病（ＤＮ）的发生与众多血管活性物质和细胞因子的作用密切相关,而这种作用主要通过蛋白激酶Ｃ（ＰＫＣ）所介导［１］。胰岛素、血管紧张素转换酶抑制剂（ＡＣＥＩ）治疗可延缓ＤＮ肾功能恶化。我们以往的研究显示初发糖尿病大鼠肾小球内ＰＫＣ活性即增强［２］,本研究的目的为进一步观察胰岛素、ＡＣＥＩ（卡托普利）对糖尿病大鼠各阶段肾小球ＰＫＣ活性的影响。 一、材料与方法 １．动物：Ｓｐｒａｇｕｅ－Ｄａｗｌｅｙ雄性大鼠１４２只,１５０～１７０ｇ。分为正常对照组刚组）,糖尿病组（ＤＭ）组,胰岛素组（ＤＩ组）及卡…     

蛋白激酶C-β抑制剂—治疗糖尿病肾病的新希望

PKC-β是一种在糖尿病相关肾病起重要作用的信号分子。抑制PKC-β的表达在动物实验中已证实能够阻止糖尿病肾病的发展，虽对人的糖尿病肾病效果尚需进一步临床试验，但它毕竟是一种新的治疗方法，为糖尿病肾病的治疗带来新希望。     

The role of protein kinase C activation in diabetic nephropathy

Diabetic nephropathy is the leading cause of end-stage renal disease worldwide and an independent risk factor for all-cause and cardiovascular mortalities in diabetic patients. New insights into the molecular mechanisms that underlie the development and progression of microvascular complications of diabetes including nephropathy are emerging rapidly from experimental and clinical studies. Chronic hyperglycemia is a major initiator of diabetic microvascular complications. Activation of diacylglycerol (DAG)-protein kinase C (PKC) pathway, enhanced polyol pathway, increased oxidative stress, and overproduction of advanced glycation end products have all been proposed as potential cellular mechanisms by which hyperglycemia induces diabetic vascular complications. The DAG-PKC pathway contributes to vascular function in many ways such as the regulation of endothelial permeability, vasoconstriction, extracellular matrix synthesis/turnover, cell growth, angiogenesis, cytokine activation, and leukocyte adhesion. We will briefly review the current knowledge base regarding the pathogenic role for the activation of DAG-PKC pathway in diabetic nephropathy and other microvascular complications of diabetes. The results from animal studies and key clinical studies investigating specific effects of the PKC isoforms on the renal and other vascular tissues to induce diabetic complications are also reviewed.     

Homocysteine induces mesangial cell apoptosis via activation of p38-mitogen-activated protein kinase

Hyperhomocysteinemia is prevalent among patients with chronic kidney disease (CKD) and has been linked to progressive kidney and vascular diseases. Increased glomerular mesangial cell (MC) turnover, including proliferation and apoptosis, is a hallmark of CKD. Activation of p38-mitogen-activated protein kinase (p38-MAPK) has been linked to apoptosis in many cell lines. Accordingly, we studied the effect of homocysteine (Hcy) on MC p38-MAPK signalling and apoptosis. Hcy (50 microM/24 h) increased MC apoptosis as determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end labelling (TUNEL) and single-stranded DNA (ssDNA) analysis. In addition to increases in pro-caspase-3 protein and caspase-3 activity, cells exposed to Hcy manifested enhanced reactive oxygen species content. Hcy increased p38-MAPK activity (fivefold), with maximal effect at 50 microM and 20 min; p38-MAPK activation was attenuated by N-acetylcysteine (Nac) and catalase (Cat), further indicating that the effect was via oxidative stress. Confocal microscopy revealed activation and nuclear translocation of p38-MAPK that was attenuated by Cat. In addition, Hcy-induced apoptosis as determined by TUNEL and ssDNA assay was abrogated by Nac, Cat, and SB203580 (p38-MAPK inhibitor). We conclude that in MC, Hcy (i) activates p38-MAPK and increases p38MAPK nuclear translocation via an oxidative stress dependent mechanism and (ii) induces DNA damage and apoptosis that is dependent on oxidative stress and p38-MAPK activation.     

Adrenomedullin inhibits transmural pressure induced mesangial cell proliferation through activation of protein kinase A

Adrenomedullin (AM), a hypotensive peptide isolated from human pheochromocytoma, inhibits the proliferation of mesangial cells (MC) induced by mitogens such as platelet-derived growth factor. Quite recently, we have demonstrated that transmural pressure applied to cultured MC increased DNA synthesis and cell proliferation through protein kinase C and tyrosine kinase pathways. However, the modulatory effect of AM on pressure-induced cell proliferation is as yet unknown. In the present study, we examined the effect of AM on transmural pressure-induced DNA synthesis in cultured rat MC. Pressure was applied to cells placed in a sealed chamber using compressed helium. Application of pressure resulted in an increase in [(3)H]thymidine incorporation (approximately 2.0-fold). AM clearly inhibited pressure-induced DNA synthesis in a concentration-dependent manner. This inhibition was paralleled by an increase in cellular cAMP levels evoked by AM. Forskolin and dibutyryl cAMP mimicked the inhibitory effect of AM. The protein kinase A inhibitor H-89 significantly attenuated the effect of AM. Human AM(22-52)-NH(2), a putative AM receptor antagonist, reversed the inhibitory effects of AM more potently than did human CGRP(8-37), a calcitonin gene related peptide receptor antagonist. Our results suggest that AM, by acting mainly on AM-sensitive receptors, inhibits pressure-induced DNA synthesis in cultured rat MC through activation of protein kinase A. AM may play a protective role against MC proliferation in certain pathological conditions. Copyright Copyright 1999 S. Karger AG, Basel     

High glucose-enhanced mesangial cell extracellular signal-regulated protein kinase activation and alpha1(IV) collagen expression in response to endothelin-1: role of specific protein kinase C isozymes

High glucose (HG) stimulates glomerular mesangial cell (MC) expression of extracellular matrix, a process involving protein kinase C (PKC) isozymes and enhanced signaling by autocrine peptides such as endothelin-1 (ET-1). The purpose of this study was to identify the specific PKC isozymes mediating the effects of HG on MC extracellular signal-regulated protein kinase (ERK1/2) signaling and alpha1(IV) collagen expression in response to ET-1. HG (30 mmol/l for 72 h) enhanced ET-1-stimulated alpha1(IV) collagen mRNA expression from 1.2 +/- 0.1-fold to 1.9 +/- 0.2-fold (P < 0.05 vs. normal glucose [NG] + ET-1), and the effect was significantly reduced by Calphostin C or the MEK (mitogen-activated protein kinase kinase) inhibitor PD98059. In transiently transfected MCs, dominant-negative (DN)-PKC-delta, -epsilon, or -zeta inhibited ET-1 activation of ERK1/2. Likewise, downstream of ERK1/2, ET-1 stimulated Elk-1-driven GAL4 luciferase activity to 11 +/- 1-fold (P < 0.002 vs. NG + ET-1) in HG, and DN-PKC-delta, -epsilon, or -zeta attenuated this response to NG levels. HG enhanced ET-1-stimulated intracellular alpha1(IV) collagen protein expression, assessed by confocal immunofluorescence imaging, showed that individual DN-PKC-delta, -epsilon, -zeta, as well as DN-PKC-alpha and -beta, attenuated the response. Thus, HG-enhanced ET-1 stimulation of alpha1(IV) collagen expression requires PKC-delta, -epsilon, and -zeta to act through an ERK1/2-dependent pathway and via PKC-alpha and -beta, which are independent of ERK1/2.     

血浆蛋白C、血小板α-颗粒膜蛋白与糖尿病肾病

探讨凝血状态异常对糖尿病肾病发生、发展的影响。方法 采用放免法、双抗体夹心法,检测65例非胰岛素依赖性糖尿病(NIDDM)患者及15例正常人的血浆蛋白C(PC)、血浆血小板α-颗粒膜蛋白(GMP-140)及凝血因子Ⅷ:C、vWF。结果 (1)血浆PC在糖尿病微量白蛋白尿(DM_Ⅱ)组显著低于正常对照(C)组及糖尿病正常白蛋白尿(DM_Ⅰ)组;糖尿病临床蛋白尿(DM_Ⅲ)组更低;与尿白蛋白排泄率(UAER)呈负相关;(2)血浆GMP-140在DM_Ⅱ组显著高于C组及DM_Ⅰ组,而DM_Ⅲ组更高,与UAER呈正相关;(3)PC与GMP-140、Ⅷ:C、vWF呈负相关。结论 糖尿病肾病早期已显示高凝状态的存在,并可作为观察微血管病变的有价值指标。