Nicotinamide adenine dinucleotide phosphate hydrogen oxidase 2 exacerbates abdominal aortic aneurysm formation by inducing oxidative stress through autophagy inhibition.

Abstract

Abdominal aortic aneurysm (AAA) has high mortality and enhanced oxidative stress; autophagy inhibition accelerates its formation. Nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase 2 (NOX2) is responsible for generating reactive oxygen species (ROS). The aim is to clarify the mechanism of NOX2-mediated autophagy in AAA. Subcutaneous angiotensin II (AngII) infusion in ApoE^-/- mice with a high-fat diet was performed to construct an AAA animal model. NOX2 inhibitor GSK2795039 was administered. Following detection of the aortic diameter, HE, Verhoeff's Van Gieson, and MASSON staining were performed to assess pathological damage, elastin, and collagen deposition of the aorta. Immunofluorescence for alpha smooth muscle actin (α-SMA) and light chain 3 (LC3), ELISA for oxidative stress-indicators, and western blot were conducted. In vitro, primary mouse vascular smooth muscle cells (VSMCs) were randomly divided into Control, AngII, AngII+GSK2795039, AngII+rapamycin (autophagy agonist, RA), and AngII+GSK2795039+RA groups. EDU assay, cell scratch assay, and mRFP-GFP-LC3 detection were conducted. ROS was measured by dihydroethidium staining. In AAA mice, aortic diameter, pathological damage, ROS, and NOX2 expression increased, and LC3 expression decreased, which were reversed by GSK2795039. Additionally, AAA mice showed enhanced collagen deposition, osteopontin, malondialdehyde, and p62 expression, and reduced elastin, α-SMA, glutathione peroxidase (GSH-PX), GSH, superoxide dismutase, LC3II/LC3I, and Beclin-1 expression. Notably, in AngII-treated VSMCs, both GSK2795039 and RA decreased cell proliferation, migration, and ROS, and increased the number of autophagosomes and autophagolysosomes. NOX2 inhibitor GSK2795039 decelerated AAA progression by mitigating oxidative stress via the activation of autophagy, providing new potential targets for therapeutic strategies in AAA.