基于“通肾络、益脾肾”治法研究足细胞凋亡及自噬

[目的]基于中医"通肾络、益脾肾"治法,探讨通络益肾方对体外高糖培养的小鼠肾小球足细胞自噬和凋亡蛋白SIRT1、BNIP3、P62、Bax表达的调控影响。[方法]成熟无特定病原体(SPF)级SD雄性大鼠40只,随机分为正常组、中药高、中、低剂量组各10只。按照人与大鼠体表面积折算方法计算出大鼠所需中药灌胃浓度:高剂量浓度4.76 g/mL、中剂量浓度2.38 g/mL、低剂量浓度1.19 g/m L,灌胃10 d取含药血清备用。足细胞分6组,正常组5.6 mmol/L葡萄糖+10%正常大鼠血清、高糖组30mmol/L葡萄糖+10%正常大鼠血清、通络益肾方含药血清高、中、低干预组30 mmol/L葡萄糖+10%高、中、低剂量大鼠血清、高渗组甘露醇24.5 mmol/L+10%正常大鼠血清。细胞培养48 h后收集,Hoechst33342荧光染色,观察各组足细胞凋亡状况及形态变化;流式细胞仪检测足细胞凋亡率;Western Blot检测细胞内自噬标志蛋白SIRT1、P62及促凋亡蛋白BNIP3、Bax表达水平。[结果]流式细胞仪检测结果显示通络益肾方中、低剂量组可降低高糖诱导的足细胞凋亡率(P0.01或P0.05),高剂量组不能改善凋亡情况(P0.05);Hoechst33342荧光染色观察结果也证实通络益肾方中、低剂量组可降低高糖诱导的足细胞凋亡率;蛋白印迹结果显示,与高糖组相比,通络益肾方中、低剂量组自噬标志蛋白SIRT1表达升高,自噬标志蛋白P62及促凋亡蛋白BNIP3、Bax蛋白表达下降(P0.05或P0.01),高剂量组SIRT1、BNIP3、P62、Bax蛋白表达未见明显改变(P0.05)。[结论]中剂量、低剂量通络益肾方能够启动细胞自噬减少高糖刺激下体外培养足细胞凋亡,降低细胞凋亡率及凋亡蛋白的表达。     

Glomerulocystic kidney disease in a Belgian Malinois dog: an ultrastructural, immunohistochemical, and lectin-binding study

Renal cysts in the cortex of a juvenile Belgian Malinois dog with acute renal failure were studied by means of light, scanning and transmission electron microscopy, immunohistochemistry for intermediate filaments, and binding for wheat germ agglutinin (WGA), peanut agglutinin (PNA), and Maclura pomifera agglutinin (MPA) lectins to determine the morphological and histochemical features of the epithelial cells of these cysts. The cysts were renal corpuscles with expanded urinary space. Glomerular tufts were small with poorly developed capillary loops and increased mesangial matrix. Continuity with the proximal tubule was evident in some cystic glomeruli. Two cell types lined Bowman's capsule. One was squamous with a central cilium and microvilli. The other had morphological and histochemical features of immature podocytes (parietal podocytes). These cells were round and protruded into the urinary space; they had thick cytoplasmic projections that resembled foot processes of podocytes, microvilli, and filtration slits. The parietal podocytes expressed vimentin and cytokeratins and had affinity for WGA as do normal immature podocytes. These features suggest that the parietal podocytes are derived by metaplasia of the parietal cells. The basement membrane of Bowman's capsule was irregularly thickened and showed multifocal glycosylation changes with lectin histochemistry (WGA, PNA, MPA) in areas adjacent to the parietal podocytes. Histologic and ultrastructural findings in this dog are consistent with glomerulocystic kidney disease. This is the second report of canine glomerulocystic kidney disease. Features are similar to those of the human counterpart, but it is unclear whether genetic defects cause the disease in the dog. The presence of parietal podocytes in all cysts suggests that abnormal differentiation may play an important role in the pathogenesis of this type of polycystic kidney disease.     

二甲双胍对2型糖尿病模型大鼠尿nephrin排泄的影响

目的:观察二甲双胍对2型糖尿病模型大鼠尿nephrin(UNE)排泄的动态影响,探讨二甲双胍对糖尿病肾小球足细胞的保护作用?方法:将高脂膳食联合小剂量链脲佐菌素(streptozotocin,STZ)诱导的2型糖尿病大鼠随机分为3组:糖尿病模型组?二甲双胍干预组?优降糖干预组,并设正常对照组?干预前后监测血糖(BG)以及尿白蛋白(UALB)和尿nephrin排泄?8周末糖化血红蛋白(HbA1c)的变化?结果:①3组糖尿病大鼠BG及HbA1c均明显高于正常组(P < 0.05);经二甲双胍和优降糖干预后,4?8周末2组BG和HbA1c均明显低于2型糖尿病模型组(P < 0.05),但差异无统计学意义(P > 0.05);②4?8周末各糖尿病大鼠尿白蛋白/肌酐比(UACR)明显高于正常组(P < 0.05);与2型糖尿病模型组比较,二甲双胍和优降糖组UACR值明显降低(P < 0.05),4周末,两干预组间无显著性差异(P > 0.05),8周末,两组间差异有统计学意义(P < 0.05);③0?2周末,4组大鼠尿nephrin/肌酐比(UNER)差异无统计学意义,4?8周末,各糖尿病大鼠UNER均明显高于正常组(P < 0.05),二甲双胍和优降糖干预组UNER明显低于糖尿病模型组(P < 0.05),且二甲双胍组低于优降糖组(P < 0.05);④Pearson相关分析显示UNER与UACR存在正相关(r=0.846,P < 0.05)?结论:二甲双胍可以降低糖尿病肾病大鼠尿nephrin的排泄,提示对肾小球足细胞可能存在保护作用,该作用不完全依赖于血糖的降低?     

Focal and segmental glomerulosclerosis in murine models: a histological and ultrastructural characterization with immunohistochemistry correlation of glomerular CD44 and WT1 expression

Aim: Focal segmental glomerulosclerosis (FSGS) is a common progressive chronic renal disease. Podocyte injury and loss are the postulated pivotal events that trigger FSGS. In this study, the authors aim to examine the evolution of FSGS in murine models histologically, ultrastructurally and immunohistochemically with special emphasis on podocytes and parietal epithelial cells (PECs). Material and methods: FSGS resembling primary FSGS in humans was initiated in Wistar rats using intravenous Adriamycin injections. Blood and urine analysis were performed at 0, 8, and 12 weeks. Both the control kidneys and the test kidneys were harvested at 8 and 12 weeks, examined histologically and ultrastructurally and the findings correlated with the glomerular expression of immunostains specific for podocytes (WT-1) and for activated PECs (CD44). Results: FSGS developed in both 8 and 12 weeks test groups showing progressive proteinuria, podocytopathy and segmental glomerular scarring. There was a decrease in the glomerular expression of WT-1 with a concurrent increase in the glomerular expression of CD44, indicating podocyte loss with synchronous increase in activated PECs. The evolving FSGS correlated negatively with podocytes and positively with activated PECs. Conclusion: Our study shows that with podocyte injury there is podocyte effacement and loss, proteinuria, glomerular segmental adhesion and scarring, all culminating in FSGS. In addition, there is activation, hyperplasia and hypertrophy of PECs. This demonstrates that both podocyte loss and PEC activation promote FSGS. Our findings are consistent with recent investigations. More studies are required to further understand the role of these cells in the evolution of FSGS and subsequently introduce new targeted treatment modalities.     

Bedside to bench Alport syndrome research: are human urine‐derived podocytes the answer?†

In a recent issue of The Journal of Pathology, Iampietro et al isolated and characterized several clones of urine‐derived podocytes from three patients with Alport syndrome (AS) and proteinuria and one age‐matched non‐proteinuric control. They reported differential expression of genes involved in cell motility, adhesion, survival, and angiogenesis. The authors found AS podocytes to be less motile and to have significantly higher permeability to albumin compared to control podocytes, highlighting that AS podocytes may retain their phenotype even when losing contact with the glomerular basement membrane. The establishment of urine‐derived podocyte cell lines from patients with different genetic forms of AS may represent a valuable and minimally invasive tool to investigate the cellular mechanisms contributing to kidney disease progression in AS and may allow for the establishment of patient‐specific drug screening opportunities. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

APPL1 acts as a protective factor against podocytes injury in high glucose environment

APPL1, an intracellular adaptor protein, takes part in numerous metabolic reactions. Although APPL1 plays a key role in glucose metabolism via adiponectin pathway and has been proved associated with type 2 diabetes, little is known about its role in diabetic nephropathy. To explore the role of APPL1 in diabetic nephropathy, we upregulated the expression of APPL1 in cultured mouse podocytes by adenovirus infection and tested the effects of APPL1 overexpression in podocytes treated with high glucose. Here, a mouse podocyte cell line (generated from H-2Kb-tsA58 immortmouse) was cultured and divided into four groups: Group 1 (normal glucose, NG), Group 2 (high glucose, HG), Group 3 (HG and infected with control adenovirus) and Group 4 (HG and infected with Ad-APPL1). Cell vitality of Group 4 is significantly higher than Group 2, but notably lower than Group 1 (P<0.01). The apoptosis rate of Group 4 was much lower (P<0.01) than Group 2 and Group 3. A decrease in phase G0/G1 and an increase in phase S was observed in Group 4 compared with Group 2 (P<0.01). These data suggested the protective role of APPL1 overexpression in high glucose condition. Moreover, the levels of Nephrin, AMPK and p-AMPK were decreased by high-glucose treatment, but increased by APPL1 overexpression. In conclusion, in the experimental high glucose condition, APPL1 acts as a protective factor against podocytes injury through regulating AMPK signaling, and may be a new therapy target for diabetic nephropathy.     

过表达 C3aR人足细胞的构建及鉴定

目的：构建过表达C3a受体（C3aR）的肾小球足细胞株,为探讨C3aR在肾小球足细胞中的确切生理和病理意义提供细胞模型。方法设计合成人C3aR 表达单元,将其克隆到慢病毒表达载体pLenti6．3-MCS-IRES2-EGFP的多克隆位点,构建成C3aR表达载体pLenti6．3-C3aR-IRES2-EGFP;将pLenti6．3-C3aR-IRES2-EGFP和包装质粒共转染293 T细胞,包装成C3aR表达重组慢病毒LV-C3aR;以LV-C3aR感染人肾小球足细胞系HPC,根据LV-C3aR上带有杀稻瘟菌素抗性基因的特点,以杀稻瘟菌素筛选稳定转染细胞克隆;利用荧光定量PCR和细胞免疫化学分析方法对稳定转染细胞克隆的C3aR表达水平进行分析,从中鉴定出稳定过表达C3aR的人肾小球足细胞株。结果成功构建了C3aR表达载体pLenti6．3-C3aR-IRES2-EGFP;得到了高滴度的C3aR表达重组慢病毒LV-C3aR;成功构建了过表达C3aR的人肾小球足细胞株HPC-C3aR。结论成功构建C3 aR表达载体和过表达C3 aR的人肾小球足细胞株,为进一步研究C3 aR过表达在人肾小球足细胞中的病理意义提供了很好的细胞模型,也为进一步开展C3 aR在其他细胞中的生理、病理意义创造了条件。     

Requirement for TLR2 in the development of albuminuria,inflammation and fibrosis in experimental diabetic nephropathy

Inflammation and fibrosis are essential elements of diabetic nephropathy (DN). We tested the hypothesis that these elements are dependent upon Toll-like receptor 2 (TLR2) signalling by examining WT and TLR2^-/- mice in an experimental model of DN. Diabetes was induced in WT and TLR2^-/- mice by i.p. injection of streptozotocin. Kidney injury was assessed at 6, 12 and 24 weeks after induction of diabetes. Gene expression of TLR2, its endogenous ligands and downstream cytokines, chemokines and fibrogenic molecules were upregulated in kidneys from WT mice with streptozotocin diabetes. TLR2^-/- mice were protected against the development of DN, exhibiting less albuminuria, inflammation, glomerular hypertrophy and hypercellularity, podocyte and tubular injury as compared to diabetic WT controls. Marked reductions in interstitial collagen deposition, myofibroblast activation (α-SMA) and expression of fibrogenic genes (TGF-β and fibronectin) were also evident in TLR2 deficient mice. Consistent with our in vivo results, high glucose directly promoted TLR2 activation in podocytes and tubular epithelial cells (TECs) in vitro, resulting in NF-κB activation, inflammation and TGF-β production. We conclude that TLR2 was required for the full development of inflammation, kidney damage and fibrosis in this model of DN. As TLR2 is known to be expressed by intrinsic kidney cells and as high concentration glucose stimulated podocytes and TECs in vitro to express TLR2 and TLR2 ligands, pro-inflammatory and pro-fibrotic cytokines in a TLR2 dependent manner in the present study, it appears likely that TLR2 signalling in intrinsic kidney cells contributes to the pathogenesis of diabetic nephropathy.