Poly (ADP-ribose) Polymerase-1 Modulates the Enzymatic Activities of Hsp70 Via PI3K/AKT Pathway in Cultured Cardiac Myocytes
|School||Huazhong University of Science and Technology|
|Keywords||poly (ADP-ribose) polymerase PI3K/Akt Hsp70 AngⅡ|
Objective To investigate the role of poly （ADP-ribose） polymerase1 in regulation of the enymatic activities of Hsp70 through PI3K/Akt pathway in cultured rat cardiac myocytes.Methods Primary cultured neonatal cardiomyocytes were divided into 5 groups, at random. Group 1 （control group） received no treatment. Group 2 （AngⅡgroup） received treatment with AngⅡ(10-7mol/l) alone for 24 hours. Group 3（3AB group） were pretreated with 20mmol/l PARP inhibitor 3-aminobenzamide（3AB） for 1 hour, followed by incubation with AngⅡ(10-7mol/l) for 24 hours. Group 4（LV group） were pretreated with 25mmol/l PI3K inhibitor LY294002（LY）for 1 hour, followed by incubation with AngⅡ(10-7mol/l) for 24 hours. Group 5 （VAL group） were pretreated with 10-7mol/l Valsartan（VAL）for 1 hour, followed by incubation with AngⅡ(10-7mol/l) for 24 hours. PARP activity of cultured cells was measured with TCA precipitation method. Expression of PARP-1, Akt1,Hsp70 was measured with Western Blot. The interaction between PARP-1 and Akt1 was measured with Co-Immunoprecipitation.Results In cardiomyocytes AngⅡcan increase the expression of PARP-1、Akt1、Hsp70。Inhibition of PARP-1 by 3AB effectively boosted AngⅡ-induced increases in the expression of Akt1 and Hsp70. Akt1 can physically be connected with PARP-1 and it can also be poly（ADP-ribosel）ated by PARP-1 activities, while PARP-1 can also be phosphorylated. Conclusions This study illustrated that activation and overexpression of PARP-1 could decrease the expression and activity of Akt1, which can further affect the expression of Hsp70. PARP-1 modulates PI3K/Akt1 pathway both by protein-protein interaction and by poly（ADP-ribosel）ation, meanwhile ,PARP-1 may also be modulated by ways of phosphorylation.