title: NPR3 protects cardiomyocytes from apoptosis through inhibition of cytosolic BRCA1 and TNF-α.
abstract: Natriuretic peptide receptor 3 (NPR3) is a clearance receptor by binding and internalizing natriuretic peptides (NPs) for ultimate degradation. Patients with cardiac failure show elevated NPs. NPs are linked to poor long-term survival because of their apoptotic effects. However, the underling mechanisms have not been identified yet. Here we report the role of NPR3 in anti-apoptosis via the breast cancer type 1 susceptibility protein (BRCA1) and tumor necrosis factor α (TNF-α ). To demonstrate a role for NPR3 in apoptosis, stable H9C2 cardiomyocyte cell lines using shRNA to knockdown NPR3 were generated. The activities of caspase-3, 8, and 9 were significantly increased in NPR3 knockdown H9C2 cardiomyocytes. Knockdown of NPR3 increased the expression of BRCA1. Also NPR3 knockdown remarkably increased the activity of cAMP response element-binding protein (CREB), a positive regulatory element for BRCA1 expression. BRCA1 showed dispersed nuclear localization in non-cardiomyocytes while predominantly cytoplasmic localization in H9C2 cells. Meanwhile, NPR3 knockdown significantly increased TNF-α gene expression. These data show that NPR3 knockdown in H9C2 cells triggered both extrinsic and intrinsic apoptotic pathways. NPR3 protects cardiomyocytes from apoptosis through inhibition of cytosolic BRCA1 and TNF-α, which are regulators of apoptosis. Our studies demonstrate anti-apoptosis role of NPR3 in protecting cardiomyocytes and establish the first molecular link between NP system and programmed cell death.
authors: a Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic , Rochester , MN , USA.
authors: Dong
authors: D
authors: Lin
authors: b Division of Clinical Pharmacology, Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic , Rochester , MN , USA.
authors: Yubo
authors: Y
authors: Chai
authors: c School of Medicine Heart and Vascular Institute, Tulane University , New Orleans , LA , USA.
authors: Reza
authors: R
authors: Izadpanah
authors: d Division of Regenerative Medicine, Tulane National Primate Research Center, Tulane University , Covington , LA , USA.
authors: Stephen E
authors: SE
authors: Braun
authors: e School of Medicine, Heart and Vascular Institute, Tulane University , New Orleans , LA , USA.
authors: Eckhard
authors: E
authors: Alt
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D009320:Atrial Natriuretic Factor / Q000494:pharmacology; D019313:BRCA1 Protein / Q000378:metabolism*; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D019610:Cytoprotection / Q000187:drug effects*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D061986:MCF-7 Cells; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D019313:BRCA1 Protein; D010446:Peptide Fragments; D014409:Tumor Necrosis Factor-alpha; C065367:atrial natriuretic factor (4-23)NH2, de-Gln(18)-de-Ser(19)-de-Gly(20,22)-de-Leu(21)-; D009320:Atrial Natriuretic Factor; D006861:Hydrogen Peroxide; D020169:Caspases; D017461:Receptors, Atrial Natriuretic Factor; C073616:atrial natriuretic factor receptor C
keywords: (TNF-α); apoptosis; breast cancer type 1 susceptibility protein (BRCA1); cardiomyocyte; natriuretic peptide receptor-3 (NPR3); shRNA knockdown; tumor necrosis factor α