title: Angiotensin II promotes poly(ADP-ribosyl)ation of c-Jun/c-Fos in cardiac fibroblasts.
abstract: Although c-Jun/c-Fos (activator protein 1, AP1) contributes importantly to Ang II-induced cardiac fibrosis through induction of extracellular matrix protein over-expression in cardiac fibroblasts, the mechanism by which Ang II promotes c-Jun/c-Fos transactivation remains unclear. In this study, we demonstrated that c-Fos and c-Jun were poly(ADP-ribosyl)ated in cultured cardiac fibroblasts. Southwestern blot and EMSA assays showed that incubation of nuclear extracts with NAD(+) and active DNA increased the basal DNA binding activities of c-Jun (31.0+/-1.0%, P<0.01) and AP1 (14.2+/-3.1%, P<0.01); incubation of recombinant c-Fos or/and c-Jun with PARP-1, NAD(+) and active DNA increased the basal DNA binding activities of c-Jun (48.3+/-4.2%, P<0.01) and AP1 (21.2+/-1.5%, P<0.01). Treatment with Ang II promoted PARP-1 activation and enhanced poly(ADP-ribosyl)ation of c-Fos (14.1+1.1%, P<0.01) and c-Jun (15.5+/-5.6%, P<0.01). Ang II also increased the basal DNA binding activities of c-Jun (13.5+/-2.4%, P<0.01) and AP1 (18.7+/-3.5%, P<0.01) in cultured cells. Inhibition of PARP-1 by PJ34 or siRNA effectively prevented Ang II-induced increases in the DNA binding of c-Jun and AP1, and decreased AP1-driven transcription (including collagen Ialpha1 and IIIalpha1, MMP-9 and TIMP-1). This study illustrated that c-Jun and c-Fos were poly(ADP-ribosyl)ated by PARP-1, and poly(ADP-ribosyl)ation enhanced the DNA binding of AP1. Ang II promoted poly(ADP-ribosyl)ation of c-Jun and c-Fos through activation of PARP-1 and, subsequently, enhanced AP1-driven transcription in cardiac fibroblasts.
authors.affiliation: Department of Cardiology, Institute of Cardiovascular Disease, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Huang
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Chongzhe
authors.initials: C
authors.lastname: Yang
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Liao
authors.forename: Kai
authors.initials: K
authors.lastname: Huang
mesh_terms: D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D019281:Dimerization; D005347:Fibroblasts / Q000378:metabolism*; D008954:Models, Biological; D009206:Myocardium / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014158:Transcription, Genetic
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D034741:RNA, Small Interfering; D000804:Angiotensin II; D011065:Poly(ADP-ribose) Polymerases