Mishra Paras K, Tyagi Neetu, Kundu Soumi, Tyagi Suresh C
Department of Physiology & Biophysics, University of Louisville, School of Medicine, A-1215, 500 South Preston Street, Louisville, KY, 40202, USA.
Cell Biochem Biophys. 2009;55(3):153-62. doi: 10.1007/s12013-009-9063-6. Epub 2009 Aug 11.
Elevated level of homocysteine (Hcy) called hyperhomocysteinemia (HHcy) is one of the major risk factors for chronic heart failure. Although the role of Hcy in cardiac remodeling is documented, the regulatory mechanism involved therein is still nebulous. MicroRNAs (miRNAs) and dicer have been implicated in regulation of cardiovascular diseases. Dicer is the only known enzyme involved in miRNA maturation. We investigated the involvement of dicer and miRNA in Hcy-induced cardiac remodeling. HL-1 cardiomyocytes were cultured in different doses of Hcy. Total RNA was isolated and RT-PCR and real-time PCR was performed for dicer, MMP-2,-9, TIMP-1,-3, and NOX-4. MiRNA microarray was used for analyzing the differential expression of miRNAs. Individual miRNA assay was also done. Western blotting was used to assess the MMP-9 expression in HHcy cardiomyocytes. The RT-PCR results suggest that dicer expression is enhanced in HHcy cardiomyocytes suggesting its involvement in cardiac remodeling caused due to high dose of Hcy. On the other hand, high dose of Hcy increased NOX-4 expression, a marker for oxidative stress. Additionally, HHcy cardiomyocytes showed elevated levels of MMP-2,-9 and TIMP-1,-3, and reduced expression of TIMP-4, suggesting cardiac remodeling due to oxidative stress. The miRNA microarray assay revealed differential expression of 11 miRNAs and among them miR-188 show dramatic downregulation. These findings suggest that dicer and miRNAs especially miR-188 are involved in Hcy-induced cardiac remodeling.
同型半胱氨酸(Hcy)水平升高即高同型半胱氨酸血症(HHcy),是慢性心力衰竭的主要危险因素之一。尽管Hcy在心脏重塑中的作用已有文献记载,但其涉及的调控机制仍不明确。微小RNA(miRNA)和Dicer酶与心血管疾病的调控有关。Dicer是唯一已知参与miRNA成熟的酶。我们研究了Dicer和miRNA在Hcy诱导的心脏重塑中的作用。将HL-1心肌细胞培养于不同剂量的Hcy中。提取总RNA,进行Dicer、基质金属蛋白酶-2、-9、组织金属蛋白酶抑制因子-1、-3和NADPH氧化酶4的逆转录聚合酶链反应(RT-PCR)和实时定量PCR。使用miRNA微阵列分析miRNA的差异表达。也进行了单个miRNA检测。采用蛋白质免疫印迹法评估HHcy心肌细胞中基质金属蛋白酶-9的表达。RT-PCR结果表明,HHcy心肌细胞中Dicer表达增强,提示其参与高剂量Hcy所致的心脏重塑。另一方面,高剂量Hcy增加了氧化应激标志物NADPH氧化酶4的表达。此外,HHcy心肌细胞中基质金属蛋白酶-2、-9和组织金属蛋白酶抑制因子-1、-3水平升高,组织金属蛋白酶抑制因子-4表达降低,提示存在氧化应激导致的心脏重塑。miRNA微阵列检测显示11种miRNA存在差异表达,其中miR-188显著下调。这些发现表明,Dicer和miRNA尤其是miR-188参与了Hcy诱导的心脏重塑。