Cellular,synaptic, and biochemical features of resilient cognition in Alzheimer's disease

Although neuritic plaques and neurofibrillary tangles in older adults are correlated with cognitive impairment and severity of dementia, it has long been recognized that the relationship is imperfect, as some people exhibit normal cognition despite high levels of Alzheimer's disease (AD) pathology. We compared the cellular, synaptic, and biochemical composition of midfrontal cortices in female subjects from the Religious Orders Study who were stratified into three subgroups: (1) pathological AD with normal cognition (“AD-Resilient”), (2) pathological AD with AD-typical dementia (“AD-Dementia”), and (3) pathologically normal with normal cognition (“Normal Comparison”). The AD-Resilient group exhibited preserved densities of synaptophysin-labeled presynaptic terminals and synaptopodin-labeled dendritic spines compared with the AD-Dementia group, and increased densities of glial fibrillary acidic protein astrocytes compared with both the AD-Dementia and Normal Comparison groups. Further, in a discovery-type antibody microarray protein analysis, we identified a number of candidate protein abnormalities that were associated with a particular diagnostic group. These data characterize cellular and synaptic features and identify novel biochemical targets that may be associated with resilient cognitive brain aging in the setting of pathological AD.     

雷公藤多甙对糖尿病大鼠肾脏Desmin、Synaptopodin表达的影响

目的探讨雷公藤多甙对糖尿病大鼠肾脏Desmin、Synaptopodin表达的影响。方法30只雄性SD大鼠随机分为对照组（n=10）、糖尿病组（DM组,n=10）、治疗组（n=10）3组。治疗组将雷公藤多甙片以50mg·kg-1·d-1灌胃。于12周末检测24h尿蛋白量、血糖（Glu）、血肌酐（Scr）、血胱抑素C（Cys-C）。HE染色观察肾脏病理改变;免疫组化检测肾脏Desmin、Synaptopodin的表达情况。结果3组大鼠24h尿蛋白、Scr和Cys-C差异有统计学意义。治疗组24h尿蛋白、Scr和Cys-C均较糖尿病组低（P〈0．05）,差异有统计学意义。与对照组比较,糖尿病组肾小球体积增大、系膜区基质明显增生、肾小球毛细血管袢受压、基底膜增厚,而治疗组较糖尿病组有所改善。免疫组化显示：3组大鼠肾组织Desmin、Synaptopodin蛋白表达差异有统计学意义,糖尿病组Desmin表达较对照组高、Synaptopodin表达较对照组低（P〈0．05）;治疗组Desmin表达较糖尿病组低、Synaptopodin表达较糖尿病组高（P〈0.05）。结论雷公藤多甙可能通过下调糖尿病大鼠肾脏Desmin的表达、同时上调Synaptopodin表达,保护足细胞,减少尿蛋白,保护肾脏。     

Regulation of podocyte structure during the development of nephrotic syndrome

 Nephrotic syndrome is a common kidney disease seen in both children and adults. The clinical syndrome includes massive proteinuria, hypoalbuminemia, edema, and usually hypercholesterolemia. Development of these clinical changes is closely correlated with profound structural changes in glomerular epithelial cells, or podocytes, which together with the glomerular basement membrane and endothelium comprise the kidney’s blood filtration barrier. Although relatively little is known about the cellular or molecular changes which occur within podocytes during the development of nephrotic syndrome, cytoskeletal proteins very likely play a central role in these changes since they are primarily responsible for the maintenance of cell structure in almost all cells. This review focuses on: (a) the structure and function of podocytes in both the normal state and during nephrotic syndrome and (b) the potential roles of several cytoskeleton-associated proteins identified in podocytes in the development of and/or recovery from the pathophysiological cytoskeletal changes which occur in podocytes during nephrotic syndrome. Received: 18 April 1997 / Accepted: 18 July 1997     

受体相关蛋白不同区段对Heymann肾炎大鼠足细胞瞬时受体电位阳离子通道蛋白6、synaptopodin及podocalyxin表达和分布的影响

目的 观察受体相关蛋白(RAP)不同区段对被动型Heymann肾炎(PHN)大鼠足细胞瞬时受体电位阳离子通道蛋白6(TRPC6)、synaptopodin、podocalyxin表达和分布的影响.方法 给雄性SD大鼠分别注射兔抗RAP全长(RAP-FL组)、氨基端(RAP-N组)和羧基端(RAP-C组)抗血清,建立相应...     

胃袖状切除术对2型糖尿病大鼠肾功能的影响

目的 探讨胃袖状切除术对2型糖尿病大鼠肾功能的影响及其机制.方法 通过腹腔内注射链脲菌素诱导SD大鼠糖尿病模型,共有36只大鼠诱导成功.选取血糖水平居中的30只大鼠随机分成3组(血糖17.88～23.65 mmol/L,平均20.32 mmol/L):胃袖状切除组、假手术组及对照组,每组10只.术后检测大鼠一般情况、血脂、肌酐,取大鼠24 h尿液检测24 h尿微量清蛋白排泄率.行血、尿肌酐检测计算肾小球滤过率,实验结束取肾称重并对肾小球进行病理学检查,PAS染色观察肾小球系膜扩张情况,计算系膜扩张率.通过免疫组化技术检测肾小球足细胞突触极蛋白表达率,进一步明确胃袖状切除手术对糖尿病大鼠肾功能的影响的机制.检测数据的组间比较采用单因素方差分析,组间两两比较采用t检验.结果 胃袖状切除组大鼠术后死亡1只,另两组大鼠无死亡.胃袖状切除组大鼠肾小球滤过率[(8.44 ±2.10) ml·g-1·d-1]、24 h尿蛋白排泄率[(36.04±11.10) mg/d]、血脂[总胆固醇(1.66±0.23) mmol/L,甘油三酯(1.25±0.17)mmol/L]、肾脏质量[(1.61±0.06)g]、肾小球系膜扩张率[(6.14±1.50)％]和足细胞突触极蛋白表达率[(20.44±2.99)％]均优于假手术组[(15.05 ±3.01)ml·g-1·d-1、(57.01±11.34) mg/d、(2.15±0.29) mmol/L、(1.65±0.23) mmol/L、(1.93±0.07)g、(11.32±2.09)％、(10.34±1.43)％]和对照组[(14.79±2.38)ml·g-1·d-1、(62.71±16.46) mg/d、(2.23±0.21) mmol/L、(1.59±0.20) mmol/L、(1.91±0.06)g、(10.82±1.79)％、(11.13±2.43)％](t=0.781 ～5.025,P值均＜0.05).结论 胃袖状切除手术可明显改善2型糖尿病大鼠模型的肾功能,手术可能通过改善肾小球系膜扩张及保护肾小球足细胞来改善肾功能.     

突触孔蛋白和细胞色素C在棕榈酸诱导足细胞损伤中的表达及意义

目的探讨细胞骨架蛋白突触孔蛋白(synaptopodin)和细胞色素C(Cyt C)在棕榈酸所致足细胞损伤中的表达及意义。方法体外培养小鼠肾足细胞,分为正常对照组和棕榈酸组。各组细胞分别培养24h、72h和120h。应用MTT方法检测棕榈酸干预后足细胞活性的变化。应用免疫荧光及免疫印迹法检测棕榈酸干预后足细胞中synaptopodin和Cyt C蛋白的表达变化。结果与正常对照组相比,棕榈酸组足细胞活性明显下降,且呈时间依赖性。棕榈酸可上调足细胞中Cyt C蛋白的表达,并下调synaptopodin的表达。结论棕榈酸可诱导足细胞中Cyt C蛋白释放以及细胞骨架蛋白synaptopodin异常表达,可能参与了足细胞损伤。     

Increased glomerular cell (podocyte) apoptosis in rats with streptozotocin-induced diabetes mellitus: role in the development of diabetic glomerular disease

Aims/hypothesis Podocyte loss by apoptosis, in addition to favouring progression of established diabetic nephropathy, has been recently indicated as an early phenomenon triggering the initiation of glomerular lesions. This study aimed to assess the rate of glomerular cell death and its relationship with renal functional, structural and molecular changes in rats with experimental diabetes. Methods Male Sprague–Dawley rats with streptozotocin-induced diabetes and coeval non-diabetic control animals were killed at 7 days and at 2, 4 and 6 months for the assessment of apoptosis, renal function, renal structure and the expression of podocyte markers and apoptosis- and cell cycle-related proteins. Results Glomerular cell apoptosis was significantly increased in diabetic vs non-diabetic rats at 4 months and to an even greater extent at 6 months, with podocytes accounting for 70% of apoptosing cells. The increase in apoptosis was preceded by increases in proteinuria, albuminuria and mean glomerular and mesangial areas, and by reductions in glomerular cell density and content of synaptopodin and Wilms’ tumour protein-1. It coincided with the development of mesangial expansion and glomerular sclerosis, and with the upregulation/activation both of tumour protein p53, which increased progressively throughout the study, and of p21 (also known as cyclin-dependent kinase inhibitor 1A, CIP1 and WAF1), which peaked at 4 months and decreased thereafter. Conclusions/interpretation Glomerular cell (podocyte) apoptosis is not an early feature in the course of experimental diabetic glomerulopathy, since it is preceded by glomerular hypertrophy, which may decrease glomerular cell density to the point of inducing compensatory podocyte hypertrophy. This is associated with reduced podocyte protein expression (podocytopathy) and proteinuria, and ultimately results in apoptotic cell loss (podocytopenia), driving progression to mesangial expansion and glomerular sclerosis. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Podocyte proteins in Galloway-Mowat syndrome

Galloway-Mowat syndrome is an autosomal recessive disorder characterized by early onset nephrotic syndrome and central nervous system anomalies. Mutations in podocyte proteins, such as nephrin, α-actinin 4, and podocin, are associated with proteinuria and nephrotic syndrome. The genetic defect in Galloway-Mowat syndrome is as yet unknown. We postulated that in Galloway-Mowat syndrome the mutation would be in a protein that is expressed both in podocytes and neurons, such as synaptopodin, GLEPP1, or nephrin. We therefore analyzed kidney tissue from normal children (n=3), children with congenital nephrotic syndrome of the Finnish type (CNF, n=3), minimal change disease (MCD, n=3), focal segmental glomerulosclerosis (FSGS, n=3), and Galloway-Mowat syndrome (n=4) by immunohistochemistry for expression of synaptopodin, GLEPP1, intracellular domain of nephrin (nephrin-I), and extracellular domain of nephrin (nephrin-E). Synaptopodin, GLEPP1, and nephrin were strongly expressed in normal kidney tissue. Nephrin was absent, and synaptopodin and GLEPP1 expression were decreased in CNF. The expression of all three proteins was reduced in MCD and FSGS; the decrease in expression being more marked in FSGS. Synaptopodin, GLEPP1, and nephrin expression was present, although reduced in Galloway-Mowat syndrome. We conclude that the reduced expression of synaptopodin, GLEPP1, and nephrin in Galloway- Mowat syndrome is a secondary phenomenon related to the proteinuria, and hence synaptopodin, GLEPP1, and nephrin are probably not the proteins mutated in Galloway-Mowat syndrome. Received: 27 April 2001 / Revised: 15 June 2001 / Accepted: 18 June 2001     

帕立骨化醇抑制血管紧张素活性减轻足细胞损伤

目的：观察维生素D受体激动药帕立骨化醇对尿毒症大鼠肾脏的保护作用。方法：雄性SD大鼠切除右肾并结扎左肾动脉前支诱导尿毒症模型。将20只尿毒症鼠随机分为尿毒症组（UC组）、UC＋帕立骨化醇治疗组（UA组）。另设正常SD大鼠为对照组（NC组）。第10周检测大鼠血清Ca、P、1,25（OH）2D3、成纤维细胞生长因子23（FGF23）、甲状旁腺素（PTH）、血管紧张素Ⅱ（AngⅡ）、血肌酐（Scr）、白蛋白（Alb）、24h尿蛋白（24hUP）。RT—PCR检测肾小球血管紧张素原（Ang）、血管紧张素转化酶（ACE）、nephrin、synaptopodin的表达。胞核WT-1阳性细胞计数测定每个肾小球足细胞数量。结果：UC组P、FGF23、PTH、AngⅡ、Scr、Alb、24hUP较NC组显著升高（P〈0．01）,Ca、1,25（OH）2D3、Alb降低（P〈0．05或0．01）。UC组Ang、ACE mRNA的表达较NC组显著增加（P〈0．01）;nephrin、synaptopodin mRNA的表达较NC组显著降低（P〈0．01）;肾小球足细胞数目减少。帕立骨化醇改善尿毒症鼠的矿物质代谢,下调AngⅡ水平,减少尿蛋白的排泄;抑制肾小球Ang、ACE mRNA的表达,恢复nephrin、synaptopodin的表达,并维持肾小球足细胞数量。结论：帕立骨化醇可抑制尿毒症鼠肾小球血管紧张素活性,减轻足细胞损伤和脱落。