title: Molecular Mechanism of Transcriptional Regulation of Matrix Metalloproteinase-9 in Diabetic Retinopathy.
abstract: Increase in matrix metalloproteinase-9 (MMP-9) is implicated in retinal capillary cell apoptosis, a phenomenon which precedes the development of diabetic retinopathy. MMP-9 promoter has multiple sites for binding the transcriptional factors, including two for activator protein 1 (AP-1). The binding of AP-1, a heterodimer of c-Jun and c-Fos, is regulated by posttranslational modifications, and in diabetes, deacetylating enzyme, Sirt1, is inhibited. Our aim, is to investigate the molecular mechanism of MMP-9 transcriptional regulation in diabetes. Binding of AP-1 (c-Jun, c-Fos) at the MMP-9 promoter, and AP-1 acetylation were analyzed in retinal endothelial cells incubated in normal or high glucose by chromatin-immunoprecipitation and co-immunoprecipitation respectively. Role of AP-1 in MMP-9 regulation was confirmed by c-Jun or c-Fos siRNAs, and that of its acetylation, by Sirt1 overexpression. In vitro results were validated in the retina from diabetic mice overexpressing Sirt1, and in the retinal microvessels from human donors with diabetic retinopathy. In experimental models, AP-1 binding was increased at the proximal and distal sites of the MMP-9 promoter, and similar phenomenon was confirmed in the retinal microvessels from human donors with diabetic retinopathy. Silencing of AP-1, or overexpression of Sirt1 ameliorated glucose-induced increase in MMP-9 expression and cell apoptosis. Thus, in diabetes, due to Sirt1 inhibition, AP-1 is hyperacetylated, which increases its binding at MMP-9 promoter, and hence, activation of Sirt1 could inhibit the development of diabetic retinopathy by impeding MMP-9-mediated mitochondrial damage. J. Cell. Physiol. 231: 1709-1718, 2016. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Department of Ophthalmology, Kresge Eye Institute, Wayne State University, Detroit, Michigan.
authors.forename: Manish
authors.initials: M
authors.lastname: Mishra
authors.affiliation: Department of Ophthalmology, Kresge Eye Institute, Wayne State University, Detroit, Michigan.
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Flaga
authors.affiliation: Department of Ophthalmology, Kresge Eye Institute, Wayne State University, Detroit, Michigan.
authors.forename: Renu A
authors.initials: RA
authors.lastname: Kowluru
mesh_terms: D000107:Acetylation; D000368:Aged; D000818:Animals; D017209:Apoptosis; D001665:Binding Sites; D001786:Blood Glucose / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000150:complications; D003930:Diabetic Retinopathy / Q000097:blood / Q000201:enzymology* / Q000209:etiology / Q000235:genetics / Q000473:pathology; D042783:Endothelial Cells / Q000201:enzymology* / Q000473:pathology; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D012171:Retinal Vessels / Q000201:enzymology* / Q000473:pathology; D056564:Sirtuin 1 / Q000235:genetics / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D001786:Blood Glucose; D018808:Transcription Factor AP-1; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9; C501830:Mmp9 protein, mouse; D056564:Sirtuin 1