OxLDL-Stimulated Macrophages Transmit Exosomal MicroRNA-320b to Aggravate Viability, Invasion, and Phenotype Switching via Regulating PPARGC1A-Mediated MEK/ERK Pathway in Proatherogenic Vascular Smooth Muscle Cells

Lingyun Ren,^1,* Shanshan Chen^2,* and Wei Liu¹

¹Department of Anesthesiology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
²Key Laboratory for Molecular Diagnosis of Hubei Province, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China

Our previous study revealed oxidized-low density lipoprotein (oxLDL)-stimulated macrophages delivered exosomes to exacerbate vascular smooth muscle cell (VSMC) viability and invasion; and microRNA-320b was enriched in exosomes from oxLDL-stimulated macrophages. This study aimed to further explore molecular mechanisms of exosomal microRNA-320b from oxLDL-stimulated macrophages on cellular functions of VSMCs. Exosomes from oxLDL-stimulated macrophages with microRNA-320b mimic/inhibitor transfection were used to treat VSMCs. Next, microRNA-320b mimic/inhibitor, and microRNA-320b mimic with or without peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) overexpression vector were transfected into VSMCs. Viability, invasion, apoptosis, contractile/synthetic phenotype markers, and MEK/ERK pathway were detected in VSMCs. Exosomes from microRNA-320b mimic-treated macrophages promoted viability, invasion, and synthetic phenotype marker osteopontin, while suppressed apoptosis and contractile phenotype marker α-smooth muscle actin in VSMCs. Importantly, direct microRNA-320b mimic treatment aggravated viability, invasion, and synthetic phenotype transition in VSMCs. However, microRNA-320b inhibitor showed the opposite effects as microRNA-320b mimic. Next, luciferase reporter gene assay showed that microRNA-320b directly bound to PPARGC1A; microRNA-320b also inversely regulated PPARGC1A in VSMCs. Moreover, the effect of microRNA-320b mimic on cellular functions of VSMCs was hampered by PPARGC1A overexpression vector (all P < 0.05). Additionally, microRNA-320b activated MEK/ERKT pathway, which was also suppressed by PPARGC1A overexpression vector (all P < 0.05). OxLDL-stimulated macrophages deliver exosomal microRNA-320b to exacerbate viability, invasion, and synthetic phenotype transition in VSMCs via modulating PPARGC1A-mediated MEK/ERK pathway, thus participating in the progression of atherosclerosis.

Key words —— atherosclerosis; exosome; macrophage; microRNA-320b; vascular smooth muscle cell

Tohoku J. Exp. Med., 2024 January, 262(1), 13-22.

^*These two authors contributed equally to this work.

Correspondence: Wei Liu, Department of Anesthesiology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, No. 26, Shengli Street, Wuhan, Hubei 430013, China.

e-mail: liuwei8255@163.com

Lingyun Ren, Department of Anesthesiology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, No. 26, Shengli Street, Wuhan, Hubei 430013, China.

e-mail: renpizhi5@163.com