CHOP mediates XBP1S-induced renal mesangial cell necrosis following high glucose treatment.
CHOP mediates XBP1S-induced renal mesangial cell necrosis following high glucose treatment.
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DOI：
10.1016/j.ejphar.2015.03.069
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发表时间：
2015-07
影响因子：
5
通讯作者：
De-cui Shao;Jun Ni;Yang Shen;Jia Liu;Li Zhou;H. Xue;Yu Huang;Wei Zhang-;Li-min Lu
中科院分区：
文献类型：
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作者：
De-cui Shao;Jun Ni;Yang Shen;Jia Liu;Li Zhou;H. Xue;Yu Huang;Wei Zhang-;Li-min Lu
高糖（HG）诱导的系膜细胞（MC）凋亡是糖尿病肾病发病过程中的关键决定因素。 HG 诱导 MC 凋亡的信号级联涉及活性氧的过量产生。我们之前的研究表明，HG 诱导的氧化应激是通过抑制剪接/活性 X-box 结合蛋白 1 (XBP1S) 介导的，这表明 XBP1S 在 HG 诱导的 MC 凋亡中的重要性。 CHOP 是一种内质网应激相关的促凋亡信号，参与 XBP1S 的下游。在本研究中，我们探讨了 XBP1S 在调节 HG 诱导的肾 MC 细胞凋亡中的作用，然后确定了 CHOP 在这些过程中的作用。通过流式细胞术对细胞凋亡和坏死进行定量；通过蛋白质印迹分析 XBP1S、caspase3、Bax、Bcl2、BNIP3 和 CHOP 的蛋白水平。 XBP1S 的细胞定位通过免疫荧光组织化学测定。 XBP1 与 CHOP 启动子的结合通过染色质免疫沉淀测定来确定。此外，携带XBP1S基因的腺病毒（Ad-XBP1S）被用来过表达XBP1S，而CHOP的敲低是通过小干扰RNA实现的。 HG 抑制 XBP1S 的核分布并诱导 MC 凋亡和坏死。 Ad-XBP1S感染增强了XBP1S的核转位并减少了MCs的凋亡和坏死。 XBP1S 与 CHOP 的启动子区域结合并上调 CHOP 表达。相反，HG 暴露后 CHOP 表达减少，CHOP 敲除增加 MC 坏死，但不增加细胞凋亡。这些结果表明，XBP1S 保护 MC 免受 HG 诱导的细胞凋亡和坏死，而 CHOP 参与 XBP1S 调节的坏死，但不参与细胞凋亡。
High glucose (HG)-induced apoptosis in mesangial cells (MCs) is a critical determinant during the pathogenesis of diabetic nephropathy. The signaling cascade inducing MCs apoptosis by HG involves overproduction of reactive oxygen species. Our previous studies have demonstrated that HG-induced oxidative stress is mediated by suppression of spliced/active X-box binding protein 1 (XBP1S), suggesting the importance of XBP1S in HG-induced MCs apoptosis. CHOP, an endoplasmic reticulum stress-associated proapoptotic signal, is involved in downstream of XBP1S. In the present study, we explored the effect of XBP1S in modulating HG-induced apoptosis in renal MCs and then identified the role of CHOP in these processes. Apoptosis and necrosis were quantified by flow cytometry; protein levels of XBP1S, caspase3, Bax, Bcl2, BNIP3, and CHOP were analyzed by Western blotting. The cellular localization of XBP1S was determined by immunofluorescence histochemistry. The binding of XBP1 toCHOPpromoter was determined by chromatin immunoprecipitation assays. In addition, adenoviruses harboringXBP1Sgene (Ad-XBP1S) were used to overexpress XBP1S, whereas the knockdown of CHOP was achieved by small interference RNA. HG suppressed nuclear distribution of XBP1S and induced apoptosis and necrosis in MCs. Ad-XBP1S infection enhanced the nuclear translocation of XBP1S and reduced MCs apoptosis and necrosis. XBP1S bound to the promoter region ofCHOPand upregulated CHOP expression. Conversely, CHOP expression was reduced upon HG exposure and knockdown of CHOP increased necrosis but not apoptosis in MCs. These results suggest that XBP1S protected MCs from HG-induced apoptosis and necrosis, and CHOP participates in XBP1S-regulated necrosis but not apoptosis.