Apelin-13 increases expression of ATP-binding cassette transporter A1 via activating protein kinase C α signaling in THP-1 macrophage-derived foam cells
Authors: Shi-Lin Tang
Qian Lu
Yan-Yan Tang
Chao-Ke Tang
Yun-Cheng Lv
Ping-Ping He
Da-Wei Zhang
Yuchang Fu
Xin-Ping Ouyang
Guo-Jun Zhao
Xiao-Yan Liu
Hai-Jun Kuang
Journal: Atherosclerosis (2013)
Discipline: CLINICAL MEDICINE
Keywords: Apelin; PKC; ABCA1; cholesterol efflux; foam cells
Affiliations: Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Life Science Research Center, University of South China, Hengyang, Hunan 421001, China.

Abstract:  Apelin has an antiatherogenic function through activating protein kinase C (PKC) to initiate a series of cellular signaling pathways. PKC phosphorylates and stabilizes ATP-binding cassette transporter A1 (ABCA1) through inhibiting its degradation mediated by calpain. Thus, in the present study, we investigated whether apelin-13 affects expression of ABCA1 through PKC signaling. The results showed that apelin-13 dramatically increased cholesterol efflux from THP-1 macrophage-derived foam cells and reduced cellular cholesterol levels. ABCA1 protein but not mRNA levels were dramatically increased by apelin-13, and calpain-induced degradation of ABCA1 and calpain activity were suppressed with treatment of apelin-13. However, the effects of apelin-13 on ABCA1 protein expression, cellular cholesterol efflux and calpain activity were abolished by depletion of PKCα, suggesting the potential important role of PKCα. In addition, apelin-13 was shown to phosphorylate serine residues in ABCA1 through the PKCα pathway. Thus, apelin-13 appears to activate PKCα, phosphorylate ABCA1 and inhibit calpain-mediated proteolysis, thereby promoting cholesterol efflux and reducing foam cell formation. Our study herein described a possible mechanism for understanding the antiatherogenic effects of apelin on attenuating the progression of atherosclerosis. 

Retracted: No

PubPeer comments:
 Figures 4 and 5. This paper is part of a growing number of papers by the same senior author on topics related to lipid metabolism and atherosclerosis that contain questionable data and images. ![file] ![file] , 
 Copy pasted from https: doi.org 10.1016 j.atherosclerosis.2021.06.918 :  Editorial expression of concern: u201cApelin-13 increases expression of ATP-binding cassette transporter A1 via activating protein kinase C u03b1 signaling in THP-1 macrophage-derived foam cellsu201d [Atherosclerosis Volume 226, issue 2, February 2013, Pages 398u2013407]. Published:June 25, 2021. The Editors of Atherosclerosis are issuing an expression of concern to alert readers that credible concerns have been raised regarding the quality of some data in the article above. See also https: retractionwatch.com 2021 07 09 they-seem-to-mean-business-cardiology-journal-flags-papers-cited-hundreds-of-times , 
 Entry 6 from this report from the Natural Science Foundation of China (NSFC), [ Decisions on handling misconduct cases investigated and handled in 2019 ](http: www.nsfc.gov.cn publish portal0 jd 04 info80773.htm), seems to be describing the research reported here. Thanks Google Translate! ------------------------------ **Decision on handling misconduct such as Tang Chaoke s fraudulent use of the name of others to declare fund projects and other misconduct** Guoke Financial Supervision Office (2019) No. 6 The Supervisory Committee of the National Natural Science Foundation of China (hereinafter referred to as the u201cSupervisory Committeeu201d) received a report, reflecting that Tang Yanyanu2019s identity information was stolen from the Cancer Hospital Affiliated to Xiangya Medical College of Central South University, making it impossible to apply for the Youth Science Fund project. After investigation and verification, Tang Chaoke of Nanhua University was the co-mentor of Liu Xiaoyan and Tang Yanyan. Liu Xiaoyan returned to her original work unit after graduating with a master s degree in December 2012. Tang Chaoke falsely used Liu Xiaoyan s name and signed Liu Xiaoyan s name to apply for the 2013 Youth Science Fund project. During the application process, Tang Yanyan s ID card number was incorrectly filled in and relevant false information was provided. Liu Xiaoyan was unaware of the project declaration made in her name. ,