ATP-citrate lyase is essential for high glucose-induced histone hyperacetylation and fibrogenic gene upregulation in mesangial cells
ATP-citrate lyase is essential for high glucose-induced histone hyperacetylation and fibrogenic gene upregulation in mesangial cells
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DOI：
10.1152/ajprenal.00029.2017
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发表时间：
2017-08-01
影响因子：
4.2
通讯作者：
Li, Yan Chun
中科院分区：
文献类型：
--
作者：
Deb, Dilip K.;Chen, Yinyin;Li, Yan Chun
本研究的目的是研究atp -柠檬酸裂解酶（ACL）在高糖（HG）诱导的组蛋白乙酰化和纤维化基因表达中的作用，ACL是一种将柠檬酸转化为乙酰辅酶a的酶。我们最近的ChIP-Seq研究表明，HG诱导系膜细胞（MCs）全基因组组蛋白超乙酰化。在这里，我们发现MCs暴露于HG显著增加H3K9/14和H3K18标记的组蛋白乙酰化，并诱导强效促纤维化因子tgf - β 1、tgf - β 3和结缔组织生长因子（CTGF）的表达。组蛋白去乙酰化酶抑制剂进一步增强了这些促纤维化因子的诱导，而组蛋白乙酰转移酶抑制剂则抑制了这些因子的诱导，证实了组蛋白乙酰化在这一调控中的重要性。有趣的是，HG不仅上调了ACL的表达，还促进了ACL核的易位，这可以通过核提取物中ACL浓度和活性的增加来证明。与此观察结果一致的是，在HG条件下培养时，用携带绿色荧光蛋白(GFP)-ACL融合蛋白的质粒转染MCs可导致GFP核积累。用sirna沉默ACL可减轻HG诱导的组蛋白超乙酰化，以及tgf - β 1、tgf - β 3、CTGF和细胞外基质（ECM）蛋白纤维连接蛋白和IV型胶原蛋白的上调，而ACL过表达可进一步增强HG诱导组蛋白乙酰化，以及这些促纤维化因子和ECM蛋白。总的来说，这些观察结果表明，HG促进ACL的表达和转运到细胞核中，其中ACL将柠檬酸转化为乙酰辅酶a，为组蛋白乙酰化提供底物，导致纤维基因的上调。因此，ACL在糖尿病肾纤维化的表观遗传调控中起关键作用。
The goal of this study was to address the role of ATP-citrate lyase (ACL), an enzyme that converts citrate to acetyl-CoA, in high glucose (HG)-induced histone acetylation and profibrotic gene expression. Our recent ChIP-Seq studies have demonstrated that HG induces genome-wide histone hyperacetylation in mesangial cells (MCs). Here, we showed that exposure of MCs to HG markedly increased histone acetylation at the H3K9/14 and H3K18 marks and induced the expression of potent profibrotic factors TGF-beta 1, TGF-beta 3, and connective tissue growth factor (CTGF). The induction of these profibrotic factors was further enhanced by histone deacetylase inhibitor but suppressed by histone acetyl-transferase inhibitor, confirming the importance of histone acetylation in this regulation. Interestingly, HG not only upregulated ACL expression but also promoted ACL nuclear translocation, evidenced by increased ACL concentration and activity in the nuclear extracts. Consistent with this observation, transfection of MCs with a plasmid-carrying green fluorescent protein (GFP)-ACL fusion protein led to GFP nuclear accumulation when cultured in HG condition. Silencing ACL with siRNAs alleviated HG-induced histone hyperacetylation, as well as upregulation of TGF-beta 1, TGF-beta 3, CTGF, and extracellular matrix (ECM) proteins fibronectin and collagen type IV, whereas ACL overexpression further enhanced HG induction of histone acetylation, as well as these profibrotic factors and ECM proteins. Collectively, these observations demonstrate that HG promotes ACL expression and translocation into the nucleus, where ACL converts citrate to acetyl-CoA to provide the substrate for histone acetylation, leading to upregulation of fibrogenic genes. Therefore, ACL plays a critical role in epigenetic regulation of diabetic renal fibrosis.