Blockade of CXCR4 promotes macrophage autophagy through the PI3K/AKT/mTOR pathway to alleviate coronary heart disease

Fangqin Li; Jin Peng; Yanlin Lu; Ming Zhou; Jingwei Liang; Cuiyun Le; Jiuyang Ding; Jiawen Wang; Jialin Dai; Changwu Wan; Jie Wang; Peng Luo; Bing Xia

doi:10.1016/j.ijcard.2023.131303

Blockade of CXCR4 promotes macrophage autophagy through the PI3K/AKT/mTOR pathway to alleviate coronary heart disease

Int J Cardiol. 2023 Dec 1:392:131303. doi: 10.1016/j.ijcard.2023.131303. Epub 2023 Aug 29.

Authors

Fangqin Li¹, Jin Peng¹, Yanlin Lu¹, Ming Zhou², Jingwei Liang¹, Cuiyun Le¹, Jiuyang Ding¹, Jiawen Wang¹, Jialin Dai¹, Changwu Wan¹, Jie Wang¹, Peng Luo³, Bing Xia⁴

Affiliations

¹ School of Forensic Medicine, Guizhou Medical University, 9 Beijing Road, Guiyang 550000, Guizhou, China.
² School of Forensic Medicine, Zunyi Medical University, Zunyi 563000, Guizhou, China.
³ School of Forensic Medicine, Guizhou Medical University, 9 Beijing Road, Guiyang 550000, Guizhou, China. Electronic address: 519484547@qq.com.
⁴ School of Forensic Medicine, Guizhou Medical University, 9 Beijing Road, Guiyang 550000, Guizhou, China. Electronic address: 372732293@qq.com.

PMID: 37652272
DOI: 10.1016/j.ijcard.2023.131303

Abstract

Objective: Autophagy is important in regulating inflammation and cholesterol efflux, suggesting that targeting autophagy may slow down atherosclerosis (AS). Since the pathological basis of coronary artery disease (CAD) is atherosclerosis, it is crucial to investigate the role of autophagy in atherosclerosis. This study aimed to investigate the role of the chemokine CXC chemokine receptor 4 (CXCR4) in promoting macrophage autophagy through the phosphoinositide-3 kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway to alleviate coronary artery disease.

Methods: The human left coronary artery and myocardium were collected to detect CXCR4, MAP1LC3(LC3) and SQSTM1(p62) expression. ApoE-/- mice were used to establish an atherosclerosis mice model, while human monocytes (THP-1) were used to establish a foam cell model and co-cultured with foam cells using siRNACXCR4. Western blotting was conducted to quantify CXCR4, PI3K/AKT/mTOR pathway protein, LC3, Beclin1 and p62 protein levels. The left coronary artery from humans and mouse aorta and myocardium were stained with Hematoxylin and Eosin (H&E), macrophages with Oil Red O staining and foam cells were assessed by Movat's staining. CXCR4 levels, PI3K/AKT/mTOR pathway protein, LC3 and p62 were detected by immunohistochemistry (IHC) and immunofluorescence assays. Detection of autophagosomes in macrophages using transmission electron microscopy. We further assessed whether the effect of CXCR4-mediated macrophage autophagy on the formation of atherosclerosis and structural changes in the myocardium was mediated via the PI3K/AKT/mTOR signaling pathway.

Results: CXCR4 and p62 proteins were upregulated in human coronary lesions, mouse aorta, myocardial tissue, and foam cells, while LC3II/LC3I was downregulated. p85 (P-PI3K), Ser473 (P-AKT), and Ser2448 (P-mTOR) phosphorylated proteins associated with the PI3K/AKT/mTOR pathway were detected in AS and foam cell models. Upregulated CXCR4 inhibited autophagy of macrophages and increased the severity of atherosclerotic lesions. After specific knockdown of CXCR4 by adeno-associated virus (AAV9-CXCR4-RNAi) and siRNACXCR4, the above indicators were reversed, macrophage autophagy was promoted, the severity of atherosclerotic lesions was reduced, and the disorganized arrangement of myocardial architecture was improved.

Conclusion: Knockdown of CXCR4 reduces the extent of coronary artery disease by promoting macrophage autophagy through the PI3K/AKT/mTOR pathway to attenuate atherosclerosis.

Keywords: Atherosclerosis; Autophagy; CXCR4; Coronary heart disease; Macrophages; PI3K/AKT/mTOR signaling pathway.