Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
Am J Physiol Renal Physiol. 2010 Mar;298(3):F568-78. doi: 10.1152/ajprenal.00399.2009. Epub 2009 Dec 9.
Prevention of ischemia-reperfusion injury (IRI) is a challenge in clinical care of the patients with kidney transplants or acute kidney injury, and understanding of the intrinsic mechanisms of resistance to injury in the kidney will lead to a novel therapy. Clusterin, a secreted glycoprotein, is an antiapoptotic protein in cancer cells. Our study is to investigate the role of clusterin in renal IRI. Renal IRI in mice was induced by clamping renal vein and artery for 45 or 50 min at 32 degrees C. Apoptosis of renal tubular epithelial cells (TECs) was determined by FACS analysis. Clusterin expression was examined by Western blot or immunohistochemistry. Here, we showed that clusterin protein was induced in TECs following IRI, and more tubules expressed clusterin in the kidneys following ischemia at higher temperatures. In human proximal TEC HKC-8 cultures, clusterin was upregulated by removal of serum and growth factors in medium and was downregulated by TNF-alpha-IFN-gamma mixture. The levels of clusterin were positively correlated with cell survival in these conditions. Knockdown or knockout of clusterin expression enhanced the sensitivity of TECs to apoptosis. In experimental models of renal IRI, deficiency in clusterin expression worsened the injury, as indicated by a significant increase in renal tissue damage with higher levels of serum creatinine and blood urea nitrogen and by a poorer recovery from the injury in clusterin-deficient mice compared with wild-type mice. Our data indicate that the reduction of inducible expression of clusterin results in an increase in TEC apoptosis in the cultures and renders mice susceptibility to IRI, implying a protective role of clusterin in kidney injury.
预防缺血再灌注损伤（IRI）是肾移植或急性肾损伤患者临床治疗的一个挑战，而对肾脏损伤抵抗内在机制的理解将导致新的治疗方法。 簇集蛋白是一种分泌型糖蛋白，是癌细胞中的一种抗凋亡蛋白。我们的研究旨在探讨簇集蛋白在肾 IRI 中的作用。通过在 32°C 下夹闭肾静脉和动脉 45 或 50 分钟来诱导小鼠肾 IRI。通过 FACS 分析测定肾小管上皮细胞（TEC）的凋亡。通过 Western blot 或免疫组织化学检查簇集蛋白的表达。在这里，我们表明，IRI 后 TEC 中簇集蛋白诱导，在更高温度下缺血后肾脏中更多的小管表达簇集蛋白。在人近端 TEC HKC-8 培养物中，血清和生长因子去除培养基中簇集蛋白上调，并由 TNF-α-IFN-γ混合物下调。在这些条件下，簇集蛋白的水平与细胞存活率呈正相关。簇集蛋白表达的敲低或敲除增强了 TEC 对凋亡的敏感性。在肾 IRI 的实验模型中，簇集蛋白表达缺失导致损伤加重，表现为血清肌酐和血尿素氮水平升高，簇集蛋白缺陷型小鼠的损伤恢复较野生型小鼠差。我们的数据表明，诱导性簇集蛋白表达的减少导致培养物中 TEC 凋亡增加，并使小鼠易发生 IRI，表明簇集蛋白在肾损伤中起保护作用。
