Krishnamurti Uma, Zhou Bing, Fan Wei-Wei, Tsilibary Effie, Wayner Elizabeth, Kim Youngki, Kashtan Clifford E, Michael Alfred
Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota.
Fred Hutchinson Cancer Research Center, Seattle, Washington.
J Am Soc Nephrol. 2001 Apr;12(4):758-766. doi: 10.1681/ASN.V124758.
Puromycin aminonucleoside (PAN)-induced nephrosis is a well-described model of human idiopathic nephrotic syndrome, but the mechanism of PAN's effect is not completely understood. Because PAN injection into rats results in retraction of glomerular epithelial cell foot processes and glomerular epithelial cell detachment, it was hypothesized that PAN might alter the contacts between these cells and the glomerular basement membrane. The major integrin expressed by glomerular epithelial cells is alpha3beta1, which mediates attachment of these cells to extracellular matrix proteins including type IV collagen. T-SV 40 immortalized human glomerular epithelial cells were used to study PAN's effects on alpha3beta1 expression, as well as that of podocalyxin and the slit diaphragm component ZO-1. Glomerular epithelial cells were seeded into plastic flasks and allowed to attach and proliferate for 48 h. The cells were then incubated for another 48 h in media containing 0, 0.5, or 5.0 microg/ml PAN. PAN exposure resulted in dose-dependent decreases in alpha3 and beta1 expression, both at the protein level and at the mRNA level. This was accompanied by a significant decrease in the adhesion of glomerular epithelial cells to type IV collagen. PAN did not affect ZO-1 protein expression. Treatment with PAN increased the expression of podocalyxin at the protein and mRNA levels. Reduced glomerular epithelial cell expression of alpha3beta1 integrins and impaired adhesion to type IV collagen may contribute to the glomerular epithelial cell detachment from glomerular basement membrane seen in the PAN nephrosis model.
嘌呤霉素氨基核苷（PAN）诱导的肾病是一种被充分描述的人类特发性肾病综合征模型，但PAN的作用机制尚未完全明确。由于向大鼠注射PAN会导致肾小球上皮细胞足突回缩和肾小球上皮细胞脱离，因此推测PAN可能会改变这些细胞与肾小球基底膜之间的接触。肾小球上皮细胞表达的主要整合素是α3β1，它介导这些细胞与包括IV型胶原在内的细胞外基质蛋白的附着。利用T-SV 40永生化人肾小球上皮细胞来研究PAN对α3β1表达以及足细胞标记蛋白和裂孔隔膜成分ZO-1表达的影响。将肾小球上皮细胞接种到塑料培养瓶中，使其附着并增殖48小时。然后将细胞在含有0、0.5或5.0微克/毫升PAN的培养基中再孵育48小时。暴露于PAN导致α3和β1表达在蛋白质水平和mRNA水平均呈剂量依赖性下降。这伴随着肾小球上皮细胞与IV型胶原的黏附显著降低。PAN不影响ZO-1蛋白表达。用PAN处理会使足细胞标记蛋白在蛋白质和mRNA水平的表达增加。肾小球上皮细胞α3β1整合素表达降低以及与IV型胶原的黏附受损可能导致在PAN肾病模型中所见的肾小球上皮细胞与肾小球基底膜的脱离。
