Impairment of liver regeneration by the histone deacetylase inhibitor valproic acid in mice
Impairment of liver regeneration by the histone deacetylase inhibitor valproic acid in mice
复制标题
组蛋白脱乙酰酶抑制剂丙戊酸对小鼠肝再生的损害
DOI：
10.1631/jzus.b1100362
复制
发表时间：
2012-09-01
影响因子：
5.1
通讯作者：
Bu, Hong
中科院分区：
文献类型：
--
作者：
Ke, Qi;Yang, Rui-na;Bu, Hong
背景与目的：肝脏再生是一个受一组遗传和表观遗传因素调控的复杂过程。已报道了多种遗传因素，但很少有研究关注肝再生过程中的表观遗传调控。在本研究中，使用组蛋白脱乙酰酶（HDAC）抑制剂丙戊酸（VPA）来研究HDAC对肝再生的影响。方法：对2/3部分肝切除小鼠腹腔注射VPA，检测肝再生过程中肝细胞的增殖情况。处死小鼠，并在治疗后0至168小时的连续时间点收获其肝组织。通过 BrdU 测定检测 DNA 合成，并使用 Ki-67 测试细胞增殖。 Western blot分析检测细胞周期蛋白D1、细胞周期蛋白E、细胞周期蛋白依赖性激酶2（CDK2）和CDK4的表达。采用染色质免疫沉淀 (ChIP) 检测 HDAC 向靶启动子区域的募集情况，并通过 Western blot 检测靶基因的表达。结果：免疫组化分析显示，给予VPA的小鼠中BrdU和Ki-67阳性细胞减少，且BrdU峰值延迟。一致的是，细胞周期蛋白 D1 的表达也被延迟。我们通过互补DNA (cDNA) 微阵列将B-myc 鉴定为HDAC 的靶基因。肝切除（PH）后给予 VPA 的小鼠中 B-myc 的表达增加。 ChIP 测定证实 B-myc 启动子处存在 HDAC。结论：HDAC 活性对于肝再生至关重要。抑制HDAC活性可延迟肝再生并诱导肝细胞周期停滞，从而对肝再生产生抗增殖作用。
Background and objective: Liver regeneration is a complex process regulated by a group of genetic and epigenetic factors. A variety of genetic factors have been reported, whereas few investigations have focused on epigenetic regulation during liver regeneration. In the present study, valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, was used to investigate the effect of HDAC on liver regeneration. Methods: VPA was administered via intraperitoneal injection to 2/3 partially hepatectomized mice to detect hepatocyte proliferation during liver regeneration. The mice were sacrificed, and their liver tissues were harvested at sequential time points from 0 to 168 h after treatment. DNA synthesis was detected via a BrdU assay, and cell proliferation was tested using Ki-67. The expressions of cyclin D1, cyclin E, cyclin dependent kinase 2 (CDK2), and CDK4 were detected by Western blot analysis. Chromatin immunoprecipitation (ChIP) assay was used to examine the recruitment of HDACs to the target promoter regions and the expression of the target gene was detected by Western blot. Results: Immunohistochemical analysis showed that cells positive for BrdU and Ki-67 decreased, and the peak of BrdU was delayed in the VPA-administered mice. Consistently, cyclin D1 expression was also delayed. We identified B-myc as a target gene of HDACs by complementary DNA (cDNA) microarray. The expression of B-myc increased in the VPA-administered mice after hepatectomy (PH). The ChIP assay confirmed the presence of HDACs at the B-myc promoter. Conclusions: HDAC activities are essential for liver regeneration. Inhibiting HDAC activities delays liver regeneration and induces liver cell cycle arrest, thereby causing an anti-proliferative effect on liver regeneration.