肾病综合征患者尿白蛋白诱导HK-2细胞上调内皮素1的表达

目的 探讨肾病综合征(NS)患者尿白蛋白对人近端肾小管上皮细胞(HK-2)合成内皮素1(ET-1)的调节作用。 方法 从NS患者尿中提取纯化白蛋白， 分析鉴定并用以刺激HK-2细胞。 通过逆转录多聚酶链反应(RT-PCR)法和间接免疫荧光法观察不同时间及不同浓度的白蛋白对HK-2细胞表达ET-1 mRNA及蛋白质的影响，并以正常人血清白蛋白(HSA)作对照。 结果 尿白蛋白及HSA均能上调HK-2细胞ET-1 mRNA及蛋白质表达，随着刺激时间延长表达逐渐增强，到达峰值后又逐渐下降至基线水平。随着尿白蛋白及HSA浓度的增加，HK-2细胞表达ET-1 mRNA也不断增强。 血清白蛋白需达2.5 mg/ml才具有显著上调HK-2细胞ET-1 mRNA表达效应，而0.5 mg/ml尿白蛋白即可明显上调(P < 0.05)。结论 NS患者尿白蛋白与正常人血清白蛋白均可上调HK-2细胞表达ET-1，而NS患者尿白蛋白的作用强于正常人血清白蛋白。

Urine albumin from nephrotic syndrome patients up-regulates endothelin-1 expression in HK-2 cells

Objective To investigate the role of urine albumin from nephrotic syndrome patients on expression of endothelin (ET)-1 in human proximal tubular epithelial cells (HK-2). Methods Proteins were precipitated with polyethylene glycol, and albumin were purified by Sephadex-75 column chromatography from urine taken from nephrotic syndrome patients. The HK-2 cells were divided into two groups: one group incubated with the urine albumin from nephrotic syndrome patients, another with HSA. The expression of ET-1 mRNA of HK-2 cells was assessed by RT-PCR, and the level of ET-1 protein was assessed by indirect immunofluorescence. Results The urine albumin and HSA up-regulated the expression of ET-1 mRNA and protein in HK-2 cells. The expression of ET-1 protein was associated with the stimulation time, and increased in dose-dependent manner. The expression of ET-1 mRNA in HK-2 cells increased significantly when cultured with unne albumin (0.5 mg/ml) from nephrotic syndrome (P < 0.05). However, only when the HK-2 cells were cultured with HSA at 2.5mg/ml, the ET-1 mRNA were markedly increased. Conclusion The urine albumin from nephrotic syndrome patients and normal serum albumin can up-regulate expression of ET-1 in HK-2 cells, and the urine albumin stimulates ET-1 synthesis by HK-2 cells to a higher extent as compare to that of normal serum albumin.