Kresge Eye Institute, Wayne State University, Detroit, MI 48201, United States.
Kresge Eye Institute, Wayne State University, Detroit, MI 48201, United States.
Biochim Biophys Acta Mol Basis Dis. 2017 Jul;1863(7):1761-1769. doi: 10.1016/j.bbadis.2017.04.024. Epub 2017 May 3.
In diabetes, matrix metalloproteinase-9 (MMP-9) is activated, which damages mitochondria, resulting in accelerated capillary cell apoptosis. Regulation of MMP-9 is controlled by multiple transcription factors including nuclear factor-kB (NF-kB) and activator protein-1 (AP-1). Binding of these transcription factors, however, can be regulated by poly(ADP-ribose) polymerase-1 (PARP-1), which forms a strong initiation complex at the promoter region and facilitates multiple rounds of gene transcription. This complex formation with the transcription factors is regulated by posttranslational acetylation of PARP-1, and in diabetes, the deacetylating enzyme, Sirt1, is inhibited. Our aim was to understand the role of PARP-1 in transcriptional regulation of MMP-9 in the development of diabetic retinopathy. Using human retinal endothelial cells, the effect of PARP-1 inhibition (pharmacologically by PJ34, 1μM; or genetically by its siRNA) on MMP-9 expression was investigated. The effect of PARP-1 acetylation on its binding at the MMP-9 promoter, and with NF-kB/AP-1, was investigated in the cells transfected with Sirt1. In vitro results were validated in the retinal microvessels from diabetic mice either administered PJ34, or overexpressing Sirt1. Inhibition of PARP-1 ameliorated hyperglycemia-induced increase in the binding of NF-kB/AP-1 at the MMP-9 promoter, decreased MMP-9 expression and ameliorated mitochondrial damage. Overexpression of Sirt1 attenuated diabetes-induced increase in PARP-1 binding at MMP-9 promoter or with NF-kB/AP-1. Thus, PARP-1, via manipulating the binding of NF-kB/AP-1 at the MMP-9 promoter, regulates MMP-9 expression, which helps maintain mitochondrial homeostasis.
在糖尿病中，基质金属蛋白酶-9（MMP-9）被激活，导致线粒体损伤，加速毛细血管细胞凋亡。MMP-9 的调节受多种转录因子控制，包括核因子-κB（NF-κB）和激活蛋白-1（AP-1）。然而，这些转录因子的结合可以通过多聚（ADP-核糖）聚合酶-1（PARP-1）来调节，PARP-1 在启动子区域形成一个强大的起始复合物，促进多个基因的转录。该转录因子的复合物形成受 PARP-1 的翻译后乙酰化调节，在糖尿病中，去乙酰化酶 Sirt1 被抑制。我们的目的是了解 PARP-1 在糖尿病性视网膜病变中 MMP-9 转录调节中的作用。使用人视网膜内皮细胞，研究了 PARP-1 抑制（药理学上通过 PJ34，1μM；或遗传学上通过其 siRNA）对 MMP-9 表达的影响。研究了 Sirt1 转染细胞中 PARP-1 乙酰化对其在 MMP-9 启动子上的结合及其与 NF-κB/AP-1 的结合的影响。在给予 PJ34 或过表达 Sirt1 的糖尿病小鼠视网膜微血管中验证了体外结果。PARP-1 的抑制改善了高血糖诱导的 NF-κB/AP-1 在 MMP-9 启动子上的结合增加，降低了 MMP-9 的表达并改善了线粒体损伤。Sirt1 的过表达减轻了糖尿病诱导的 PARP-1 在 MMP-9 启动子上或与 NF-κB/AP-1 的结合增加。因此，PARP-1 通过调节 NF-κB/AP-1 在 MMP-9 启动子上的结合来调节 MMP-9 的表达，有助于维持线粒体的动态平衡。
