Renal Ischemia-Induced Cholesterol Loading Transcription Factor Recruitment and Chromatin Remodeling along the HMG CoA Reductase Gene
Renal Ischemia-Induced Cholesterol Loading Transcription Factor Recruitment and Chromatin Remodeling along the HMG CoA Reductase Gene
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DOI：
10.2353/ajpath.2009.080602
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发表时间：
2009-01-01
影响因子：
6
通讯作者：
Zager, Richard A.
中科院分区：
文献类型：
--
作者：
Naito, Masayo;Bomsztyk, Karol;Zager, Richard A.
急性肾损伤引起肾小管胆固醇合成。然而，急性肾损伤期间调节 HMG CoA 还原酶 (HMGCR) 活性（胆固醇合成的限速步骤）的因素尚未明确。为了研究这些因素，in-ice 接受了 30 分钟的单侧肾缺血或假手术。 3天后，进行双侧肾切除术并制备皮质组织提取物。通过基质 ChIP 测定评估 RNA 聚合酶 II (Pol II)、转录因子（SREBP-1、SREBP-2、NF-kappa B、c-Fos 和 c-Jun）和热休克蛋白（HSP-70 和血红素加氧酶-1）向 HMGCR 启动子和转录区域（起始/终止外显子）的募集情况。测定了 HMGCR mRNA、蛋白质和胆固醇水平。最后，评估了 HMGCR 处的组蛋白修饰。缺血/再灌注 (I/R) 诱导显着的胆固醇负荷，这与 HMGCR 中 Pol H 募集的增加以及 HMGCR 蛋白和 mRNA 表达水平的增加相对应。 I/R 还诱导多种转录因子（SREBP-1、SREBP-2、c-Fos、c-Jun、NF-kappa B）和热休克蛋白与 HMGCR 启动子和转录区域结合。在这些位点也观察到显着的组蛋白修饰（H3K4m3、H3K19Ac 和 H2A.Z 变体增加），但在 5' 和 3' HMGCR 侧翼区域（+/- 5000 bps）或阴性对照基因（β-肌动蛋白和 β-珠蛋白）均未发现。总之，I/R 通过多种应激激活转录和表观遗传途径激活 HMGCR 基因，导致肾脏胆固醇负荷。 (Am J Pathol 2009, 174:54-62; DOI.10.2353/ajpath.2009.080602)
Acute kidney injury evokes renal tubular cholesterol synthesis. However, the factors during acute kidney injury that regulate HMG CoA reductase (HMGCR) activity, the rate-limiting step in cholesterol synthesis, have not been defined. To investigate these factors, in-ice were subjected to 30 minutes of either unilateral renal ischemia or sham surgery. After 3 days, bilateral nephrectomy was performed and cortical tissue extracts were prepared. The recruitment of RNA polymerase II (Pol II), transcription factors (SREBP-1, SREBP-2, NF-kappa B, c-Fos, and c-Jun), and heat shock proteins (HSP-70 and heme oxygenase-1) to the HMGCR promoter and transcription region (start/end exons) were assessed by Matrix ChIP assay. HMGCR mRNA, protein, and cholesterol levels were determined. Finally, histone modifications at HMGCR were assessed. Ischemia/reperfusion (I/R) induced marked cholesterol loading, which corresponded with elevated Pol H recruitment to HMGCR and increased expression levels of both HMGCR protein and mRNA. I/R also induced the binding of multiple transcription factors (SREBP-1, SREBP-2, c-Fos, c-Jun, NF-kappa B) and heat shock proteins to the HMGCR promoter and transcription regions. Significant histone modifications (increased H3K4m3, H3K19Ac, and H2A.Z variant) at these loci were also observed but were not identified at either the 5' and 3' HMGCR flanking regions (+/- 5000 bps) or at negative control genes (beta-actin and beta-globin). In conclusion, I/R activates the HMGCR gene via multiple stress-activated transcriptional and epigenctic pathways, contributing to renal cholesterol loading. (Am J Pathol 2009, 174:54-62; DOI. 10.2353/ajpath.2009.080602)