title: AKAP150 mobilizes cPKC-dependent cardiac glucotoxicity.
abstract: Activation of conventional PKCs (cPKC) is a key signaling that directs the cardiac toxicity of hyperglycemia. AKAP150, a scaffold protein of the A-kinase anchoring proteins (AKAPs) family, is less defined regarding its capability to anchor and regulate cardiac cPKC signaling. This study was designed to investigate the role of AKAP150 in cPKC-mediated cardiac glucotoxicity. In cardiac tissues from streptozotocin-induced diabetic rats and high-glucose-treated neonatal rat cardiomyocytes, both mRNA and protein levels of AKAP150 increased significantly, and marked elevations were observed in cPKC activity and both expression and phosphorylation levels of p65 NF-κB and p47(phox). AKAP150 knockdown was established via intramyocardial injection in vivo and transfection in vitro of adenovirus carrying AKAP150-targeted shRNA. Downregulation of AKAP150 reversed diabetes-induced diastolic dysfunction as manifested by decreased left ventricular end-diastolic diameter and early/late mitral diastolic wave ratio. AKAP150 inhibition also abrogated high-glucose-induced cardiomyocyte apoptosis (TUNEL staining and annexin V/propidium iodide flow cytometry) and oxidative stress (ROS production, NADPH oxidase activity, and lipid peroxidation). More importantly, reduced AKAP150 expression significantly inhibited high-glucose-induced membrane translocation and activation of cPKC and suppressed the increases in the phosphorylation of p65 NF-κB and p47(phox). Immunofluorescent coexpression and immunoprecipitation indicated enhanced anchoring of AKAP150 with cPKC within the plasma membrane under hyperglycemia, and AKAP150 preferentially colocalized and functionally bound with PKCα and -β isoforms. These results suggest that cardiac AKAP150 positively responds to hyperglycemia and enhances the efficiency of glucotoxicity signaling through a cPKC/p47(phox)/ROS pathway that induces myocardial dysfunction, cardiomyocyte apoptosis, and oxidative stress.
authors.affiliation: Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and.
authors.forename: Chao
authors.initials: C
authors.lastname: Zeng
authors.affiliation: Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and.
authors.forename: Jinyi
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and Department of Cardiology, Hainan Branch of the PLA General Hospital, Sanya, China.
authors.forename: Mingzhi
authors.initials: M
authors.lastname: Shen
authors.affiliation: Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and.
authors.forename: Dongjuan
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and yuqiujun@gmail.com.
authors.forename: Qiujun
authors.initials: Q
authors.lastname: Yu
authors.affiliation: Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and.
authors.forename: Haichang
authors.initials: H
authors.lastname: Wang
mesh_terms: D054758:A Kinase Anchor Proteins / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000378:metabolism; D058065:Diabetic Cardiomyopathies / Q000378:metabolism* / Q000473:pathology; D005947:Glucose / Q000633:toxicity; D057809:HEK293 Cells; D006331:Heart Diseases / Q000209:etiology* / Q000378:metabolism; D006801:Humans; D006943:Hyperglycemia / Q000150:complications* / Q000378:metabolism; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000502:physiology; D018384:Oxidative Stress / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D054758:A Kinase Anchor Proteins; C415703:Akap5 protein, rat; D011493:Protein Kinase C; D005947:Glucose
keywords: AKAP150; cardiomyocyte; conventional PKC; glucotoxicity; oxidative stress