Title:Protective Role of Cytochrome C Oxidase 5A (COX5A) against Mitochondrial
Disorder and Oxidative Stress in VSMC Phenotypic Modulation and
Neointima Formation
Volume: 21
Issue: 2
Author(s): Haijing Guan, Jingwen Sun, Xiuying Liang and Wenjuan Yao*
Affiliation:
- School of Pharmacy, Nantong University, 19 QiXiu Road, Nantong, 226001, China
Keywords:
COX5A, mitochondrial respiratory chain, VSMC phenotypic modulation, intimal hyperplasia, oxidative stress, cytochrome c.
Abstract:
Background: The pathological role of cytochrome c oxidase 5A (COX5A) in vascular neointima
formation remains unknown.
Aim: This study aims to investigate the role of COX5A on platelet-derived growth factor BB (PDGFBB)-
mediated smooth muscle phenotypic modulation and neointima formation and clarify the molecular
mechanisms behind this effect.
Methods: For in vitro assays, human aortic vascular smooth muscle cells (HA-VSMCs) were transfected
with pcDNA3.1-COX5A and COX5A siRNA to overexpress and knockdown COX5A, respectively.
Mitochondrial complex IV activity, oxygen consumption rate (OCR), H2O2 and ATP production, reactive
oxygen species (ROS) generation, cell proliferation, and migration were measured. For in vivo assays,
rats after balloon injury (BI) were injected with recombinant lentivirus carrying the COX5A gene.
Mitochondrial COX5A expression, carotid arterial morphology, mitochondrial ultrastructure, and ROS
were measured.
Results: The results showed that PDGF-BB reduced the level and altered the distribution of COX5A in
mitochondria, as well as reduced complex IV activity, ATP synthesis, and OCR while increasing H2O2
synthesis, ROS production, and cell proliferation and migration. These effects were reversed by overexpression
of COX5A and aggravated by COX5A knockdown. In addition, COX5A overexpression attenuated
BI-induced neointima formation, muscle fiber area ratio, VSMC migration to the intima, mitochondrial
ultrastructural damage, and vascular ROS generation.
Conclusion: The present study demonstrated that COX5A protects VSMCs against phenotypic modulation
by improving mitochondrial respiratory function and attenuating mitochondrial damage, as well as
reducing oxidative stress, thereby preventing neointima formation.