NFAT2 mediates high glucose-induced glomerular podocyte apoptosis through increased Bax expression
NFAT2 mediates high glucose-induced glomerular podocyte apoptosis through increased Bax expression
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NFAT2通过增加Bax表达介导高糖诱导的肾小球足细胞凋亡
DOI：
10.1016/j.yexcr.2013.01.007
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发表时间：
2013-04-15
影响因子：
3.7
通讯作者：
Wang, Wenjian
中科院分区：
文献类型：
--
作者：
Li, Ruizhao;Zhang, Li;Wang, Wenjian
背景：高血糖促进足细胞凋亡，在糖尿病肾病的发病机制中起关键作用。然而，介导高血糖诱导足细胞凋亡的机制仍远未完全了解。近年来有研究报道，高糖可激活血管平滑肌或胰腺β细胞中的活化T细胞核因子（NFAT）。在这里，我们试图确定高血糖是否激活培养足细胞中的NFAT2，以及这是否导致足细胞凋亡。同时，我们也进一步探讨了NFAT2激活的机制，以及NFAT2介导高糖诱导的足细胞凋亡。方法：在含正常葡萄糖（NG）、高糖（HG）或HG加环孢素A（一种钙化素药理抑制剂）或IR-VIVIT（一种特殊的NFAT2抑制剂）的培养基中培养永生化小鼠足细胞。western blotting和免疫荧光法检测足细胞中NFAT2的活化情况。通过流式细胞仪观察11R-VIVIT对NFAT2活化的抑制作用，进一步探讨NFAT2在高血糖诱导足细胞凋亡中的作用。使用Fluo-3/AM监测hg处理的足细胞内细胞内Ca2+。采用real - time-qPCR和western blotting检测凋亡基因Bax的mRNA和蛋白表达。结果：HG刺激在培养足细胞中激活NFAT2呈时间和剂量依赖性。环孢素A （500 nM）或11R-VIVIT （100 nM）预处理完全阻断NFAT2核积累。同时，与11R-VIVIT同时处理也可以消除HG诱导的足细胞凋亡效应。我们进一步发现HG还增加了[Ca2+]i，导致钙调磷酸酶的激活，随后增加了培养足细胞中NFAT2的核积累和Bax的表达。结论：我们的研究发现hg诱导足细胞凋亡是由钙调神经磷酸酶/NFAT2/Bax信号通路介导的，这可能是一个有希望的治疗干预靶点。(C) 2013爱思唯尔公司版权所有。
Background: Hyperglycemia promotes podocyte apoptosis and plays a key role in the pathogenesis of diabetic nephropathy. However, the mechanisms that mediate hyperglycemia-induced podocyte apoptosis is still far from being fully understood. Recent studies reported that high glucose activate nuclear factor of activated T cells (NFAT) in vascular smooth muscle or pancreatic beta-cells. Here, we sought to determine if hyperglycemia activates NFAT2 in cultured podocyte and whether this leads to podocyte apoptosis. Meanwhile, we also further explore the mechanisms of NFAT2 activation and NFAT2 mediates high glucose-induced podocyte apoptosis.Methods: Immortalized mouse podocytes were cultured in media containing normal glucose (NG), or high glucose (HG) or HG plus cyclosporine A (a pharmacological inhibitor of calcinerin) or I IR-VIVIT (a special inhibitor of NFAT2). The activation of NFAT2 in podocytes was detected by western blotting and immunofluorescence assay. The role of NFAT2 in hyperglycemia-induced podocyte apoptosis was further evaluated by observing the inhibition of NFAT2 activation by 11R-VIVIT using flow cytometer. Intracellular Ca2+ was monitored in HG-treated podcocytes using Fluo-3/AM. The mRNA and protein expression of apoptosis gene Bax were measured by real time-qPCR and western blotting.Results: HG stimulation activated NFAT2 in a time- and dose-dependent manner in cultured podocytes. Pretreatment with cyclosporine A (500 nM) or 11R-VIVIT (100 nM) completely blocked NFAT2 nuclear accumulation. Meanwhile, the apoptosis effects induced by HG were also abrogated by concomitant treatment with 11R-VIVIT in cultured podocytes. We further found that HG also increased [Ca2+]i, leading to activation of calcineurin, and subsequent increased nuclear accumulation of NFAT2 and Bax expression in cultured podocytes.Conclusion: Our results identify a new finding that HG-induced podocyte apoptosis is mediated by calcineurin/NFAT2/Bax signaling pathway, which may present a promising target for therapeutic intervention. (C) 2013 Elsevier Inc. All rights reserved.