Fluvastatin attenuates the down?regulation of β1 integrin expression in PAN?treated podocytes by inhibiting ROS

Objective To investigate the effect of fluvastatin（FLV）on the expression of β1 integrin in puromycin aminonucleoside (PAN)?treated podocytes and its mechanism. Methods Cultured human podocytes were divided into PAN, different concentrations of fluvastatin（1×10-8 to 1×10-5 mol/L）,SOD, H2O2 groups respectively. Expressions of β1 integrin and reactive oxygen species (ROS) in podocytes were detected by Western blotting and DCFHDA (2’7’?Dichlorofluoresecein 3’6’?diacetate) respectively. The viability of podocyte was determined by MTT colorimetry. Results PAN and H2O2 significantly decreased the expression of β1 integrin and increased the synthesis of ROS in podocytes (P<0.05 respectively). Lower concentration fluvastatin or SOD treatment up?regulated β1 integrin and down?regulated ROS of podocytes induced by PAN (P<0.05 respectively). MTT revealed that lower podocyte viability was found in higher concentration fluvastatin, PAN and H2O2 groups. Lower concentration fluvastatin and SOD could protect podocytes against PAN. Conclusion Fluvastatin attenuates the injury of podocyte induced by PAN and increases the expression of β1 integrin, whose mechanism may be associated with the inhibition of the ROS activity.     

血管紧张素Ⅱ对小鼠足细胞小窝蛋白1表达的影响

目的 观察血管紧张素Ⅱ（AngⅡ）刺激及氯沙坦干预对足细胞小窝蛋白1（caveolin-1）表达的影响,探讨caveolin-1在足细胞损伤中的作用.方法 体外培养永生化小鼠足细胞（MPC）,AngⅡ（10-6mol/L）刺激不同时间（3 h、6h、12 h和24 h）;Losartan（10-6 mol/L）提前预处理3h后与AngⅡ（10-6 mol/L）共孵育6h,Hoechst-33342检测足细胞凋亡率,Western-blot法检测各组细胞caveolin-1蛋白表达,免疫荧光检测caveolin-1及其磷酸化水平.结果 ①AngⅡ刺激3h,足细胞即开始发生凋亡,随着刺激时间的延长,足细胞凋亡明显增多（P＜0.05）.②AngⅡ刺激不同时间caveolin-1表达总量无明显改变（P＞0.05）,从3h开始,caveolin-1磷酸化水平明显增高（P＜0.05）.③Losartan干预后caveolin-1磷酸化水平明显降低（P＜0.05）.结论 caveolin-1可能在AngⅡ诱导的足细胞损伤中发挥着重要的作用.     

New insights into human minimal change disease: lessons from animal models

The pathogenesis of minimal change disease (MCD), considered to be the simplest form of nephrotic syndrome, has been one of the major unsolved mysteries in kidney disease. In this review, recent landmark studies that have led to the unraveling of MCD are discussed. A recent study now explains the molecular basis of major clinical and morphologic changes in MCD. Overproduction of angiopoietin-like 4 (ANGPTL4) in podocytes in MCD causes binding of ANGPTL4 to the glomerular basement membrane, development of nephrotic-range selective proteinuria, diffuse effacement of foot processes, and loss of glomerular basement membrane charge, but is not associated with changes shown by light microscopy in the glomerular and tubulointerstitial compartments. At least some of this ability of ANGPTL4 to induce proteinuria is linked to a deficiency of sialic acid residues because oral supplementation with sialic acid precursor N-acetyl-d-mannosamine improves sialylation of podocyte-secreted ANGPTL4 and significantly decreases proteinuria. Animal models of MCD, recent advances in potential biomarkers, and studies of upstream factors that may initiate glomerular changes also are discussed. In summary, recent progress in understanding MCD is likely to influence the diagnosis and treatment of MCD in the near future.     

Repair problems in podocytes: wnt, notch, and glomerulosclerosis

Wnt/Ctnnb1 and Notch signaling play key roles in kidney development and epithelial cell specification. Recent reports have suggested that these pathways are reactivated in response to injury and in different disease conditions. Studies using genetically modified animal models showed that sustained activation of Notch and Wnt signaling in podocytes are causally related to albuminuria and glomerulosclerosis development. Here, we discuss the role and regulation of Wnt/Ctnnb1 and Notch signaling in podocytes.     

Signaling from the podocyte intercellular junction to the actin cytoskeleton

Observations of hereditary glomerular disease support the contention that podocyte intercellular junction proteins are essential for junction formation and maintenance. Genetic deletion of most of these podocyte intercellular junction proteins results in foot process effacement and proteinuria. This review focuses on the current understanding of molecular mechanisms by which podocyte intercellular junction proteins such as the nephrin-neph1-podocin-receptor complex coordinate cytoskeletal dynamics and thus intercellular junction formation, maintenance, and injury-dependent remodeling.     

足细胞损伤与糖尿病肾病的研究进展

糖尿病肾病是糖尿病的严重并发症,其主要临床特点为尿蛋白排泄率逐年增加、肾功能减退至终末期肾病。近年来,肾小球滤过屏障结构和功能的改变,尤其是作为肾小球滤过屏障结构成分的足细胞在糖尿病肾病发生、发展中的作用,成为研究热点。足细胞是一种终末分化的多突状细胞,足细胞的损伤与蛋白尿的发生、发展密切相关,现通过对常见足细胞损伤的表现,及针对足细胞损伤的机制和治疗予以综述。     

Neonatal Fc receptor stimulation induces ubiquitin c-terminal hydrolase-1 overexpression in podocytes through activation of p38 mitogen-activated protein kinase

Ubiquitin c-terminal hydrolase-1 is overexpressed in renal podocytes in some immune complex-mediated glomerulonephritides, an effect closely related to extensive podocyte injury. Neonatal Fc receptor is newly recognized to be present on human renal podocytes. It is presumed that neonatal Fc receptor serves as a sensor for immune stimulation transduction and is involved in the pathogenesis of podocyte injury. In our current study, we found that neonatal Fc receptor was constitutively expressed in normal podocytes and up-regulated by immune stimulation induced by antithymocyte serum. An increase in neonatal Fc receptor expression was observed in human podocytes within diseased glomeruli in 97 cases of various glomerulonephritides. The expression percentage was significantly higher in immune-mediated disease, including membranous nephropathy (46.7%), immunoglobin A nephropathy (66.7%), lupus nephritis (87.5%), and acute proliferative glomerulonephritis (100%), than in normal kidney samples (16.7%) (P < .05), whereas there was no significant difference between minimal-change disease and normal kidney. Further study showed that neonatal Fc receptor up-regulated the expression of ubiquitin c-terminal hydrolase-1 via activation of p38 in podocytes subjected to immune stimulation in vitro. These data suggest that neonatal Fc receptor acts as an immune sensor that evokes an inflammatory response, which may lead to functional and morphological changes in podocytes in glomerulonephritides.     

肾小球疾病患者尿沉渣足细胞分子podocin和podocalyxin分析

目的：以ELISA法检测尿沉渣足细胞podocin,podocalyxin排泌并观察其与不同肾小球疾病的关系。方法：共收集我院自2010年5月～8月以来行肾活检证实为肾小球疾病的患者,收集其临床资料,并以ELISA法检测尿沉渣足细胞分子podocin,podocalyxin。结果：共40个患者,男15例,女25例,平均年龄（38.27±16.33）岁,增殖性肾小球疾病患者19例：IgA肾病10例,新月体性肾炎2例,IgM肾病2例,Ⅳ（A/G）型狼疮性肾炎5例;非增殖性肾小球疾病患者19例：微小病变型（MCD）5例,局灶节段硬化性肾小球肾炎（FSGS）8例,膜性肾病（MN）6例,另原发性肾淀粉样变性2例,对照健康自愿者10例。尿podocin分子排泌在正常对照组最低,在增殖性肾小球疾病和非增殖性肾小球疾病间差异无统计学意义（P〉0.05）,增殖性肾小球疾病尿podocin排泌高于肾淀粉样变性患者（P〈0.05）。新月体肾炎的尿podocin排泌显著高于其他肾小球疾病（P〈0.05）,后依次FSGS,IgA肾病,狼疮性肾炎,MN,IgM肾病,MCD;尿沉渣podocalyxin排泌在正常对照组最低,而增殖性肾小球肾炎和非增殖性肾小球肾炎间差异无统计学意义（P〉0.05）。新月体肾炎尿podocalyxin排泄量最高,其后依次为FSGS,IgA肾病,MN,狼疮性肾炎,MCD,IgM肾病,以肾淀粉样变性最低。尿podocalyxin与podocin呈正相关,尿podocin与血C3呈负相关。结论：ELISA法检测尿沉渣足细胞分子检测可对肾小球疾病患者的肾病理类型提供参考,以正常人尿podocin,podocalyxin排泌最少,增殖性肾小球疾病和非增殖性肾小球疾病间差异无统计学意义,新月体性肾炎尿沉渣podocin及Podocalyxin高于其他疾病患者,FSGS患者的尿沉渣podocin及Podocalyxin排泌量也较多,肾淀粉样变性患者的尿沉渣podocin及Podocalyxin最低,血清C3与尿podocin的排泌呈负相关。     

乙型肝炎病毒对肾脏直接作用的研究进展

目前研究表明乙型肝炎病毒(HBV)直接作用于肾脏细胞,是HBV相关性肾炎的发病机制之一。HBV可感染肾脏细胞,并原位复制,表达HBAg及HBV x蛋白作用于肾脏细胞,参与HBV相关性肾炎的发病过程,诱导肾小球系膜细胞增殖、促进其分泌炎性细胞因子;改变足细胞调节蛋白的表达水平,促进足细胞凋亡;激活肾小管上皮细胞信号转导通路,诱导肾小管上皮细胞凋亡。     

缬沙坦联合辛伐他汀对早期糖尿病肾病大鼠肾脏的保护作用

目的 探讨降脂药辛伐他汀及血管紧张素Ⅱ受体拮抗剂类药物缬沙坦对早期糖尿病肾病大鼠肾脏的保护作用.方法 用链脲佐菌素(STZ)诱导糖尿病肾病大鼠模型,将SD大鼠随机分成5组,每组10只:正常对照组(C组)、糖尿病肾病组(D组)、缬沙坦组(X组)、辛伐他汀组(Z组)和缬沙坦及辛伐他汀联合组(L组).5周末检测5组大鼠血糖(BG)、糖化血红蛋白(HbA1c)、总胆固醇(TC)、甘油三酯(TG)、血尿素氮(BUN)、肌酐(SCr)、肌酐清除率(Ccr)、尿白蛋白排泄率(UAER)等指标的变化;利用透射电子显微镜观察肾脏足细胞超微病理结构.结果 D组与C组比较,BG[分别为(20.3±3.2)、(6.1±0.4)mmol/L]、HbA1c[分别为(7.18±0.47)%、(3.37±0.15)%]、TC[分别为(2.69±0.35)、(1.28±0.24)mmol/L]、TG[分别为(3.09±0.37)、(1.18±0.25)mmol/L]明显升高(P均＜0.05);D组Ccr[(0.89±0.19)ml/min]较C组[(1.27±0.33)ml/min]和X、Z、L组显著下降(P＜0.05),D组大鼠UAER[(19.87±3.85)μg/24 h]明显高于C组[(3.67±1.01)μg/24 h](P＜0.05),X、Z、L组大鼠UAER显著低于D组(P＜0.05),而L组改善尤其显著(P＜0.05);D组的足细胞足突严重融合,X、Z、L组仅少量足突融合较D组改善,而L组改善尤其显著.结论 缬沙坦及辛伐他汀单用及联合应用,尤其是联合用药对早期糖尿病大鼠肾脏有保护作用.

Abstract：

Objective To explore the protection of valsartan combined with simvastatin on kidney in early diabetic nephropathy rats. Methods Diabetic nephropathy rats model were induced by streptozocin (STZ) ,the experimental rats were randomly divided into 5 groups: control (group C), diabetic nephropathy (group D) ,diabetes treated with valsartan (group X) ,diabetes treated with simvastatin (group Z) ,and diabetes treated with combined valsartan and simvastatin ( group L). Blood glucose (BG), HbA1c, blood cholesterol ( TC), trigalloylglycerol ( TG ), blood ureanitrogen ( BUN ), serum creatinine (SCr) , urinary albumin excretion rate (UAER) were measured, and the podocyte ultrastructure was observed by transmission electronic microscopy. Results The levels of BG, HbA1c,TC,TG and UAER in group D increased significantly compared togroup C(BG:[20.3 ±3.2]mmol/L vs [6.1 -±0. 4]mmol/L;HbA1c:[7.18 ±0.47]% vs [3.37 ±0. 15]% ;TC: [2. 69 ±0. 35] mmol/L vs [1.28 ±0. 24] mmol/L;TG: [3.09 ±0. 37] mmol/L vs [1.18 ±0. 25]mmol/L) (P ＜ 0. 05 ). Creatinine clearance rates (Ccr) in group D ( [0. 89 ± 0. 19] ml/min ) decreased significantly compared to group C( [1.27 ±0. 33] ml/min) ,as well as group X,Z and L( Ps ＜ 0. 05 ). UAER in group D was significantly higher than that in group C ( [19. 87 ±3. 85] μg/24 h vs [3. 67 ± 1.01] μg/24 h) (P ＜ 0. 05 ), as well as group X, Z and L ( P ＜ 0. 05 ), and the improvement in group L was particularly significant ( P ＜ 0. 05 ). The projections of podocyte in group D severely syncretized, there were slightly improvement in group X, Z and L compared to group D, and the improvement in group L was remarkable. Conclusion The treatment with valsartan, simvastatin and their combination will effectively protect the kidney in early diabetic nephropathy rats,and the effect of using the combination therapy is much better.