CircBRWD1 Drives Atherosclerotic Plaque Progression by Modulating Macrophage Inflammatory Responses Through miR-141-5p/HMGB1/NF-κB Signaling.

Atherosclerosis is a chronic inflammatory vascular disease. Circular RNAs (circRNAs) have emerged as important regulators of inflammatory processes, but their roles and regulatory mechanisms in atherosclerosis remain incompletely understood. This study aimed to investigate the role of circBRWD1 in atherosclerosis and its involvement in macrophage inflammatory responses. The expression and cellular localization of circBRWD1 were examined in high fat diet (HFD)-fed Apolipoprotein E knockout (ApoE-/-) mice using qRT-PCR, fluorescence in situ hybridization (FISH) and immunofluorescence. The effects of AAV-mediated circBRWD1 knockdown on atherosclerotic lesions and plaque-associated inflammatory responses were evaluated in ApoE-/- mice. The regulatory effects of circBRWD1 on macrophage inflammatory responses were further investigated in RAW264.7 macrophages using qRT-PCR, western blotting, ELISA and flow cytometry. The interaction between circBRWD1 and miR-141-5p and the regulation of HMGB1 by miR-141-5p were investigated using bioinformatic prediction, RNA pull-down, RNA immunoprecipitation, FISH, dual-luciferase reporter assays and functional rescue experiments. CircBRWD1 expression increased during atherosclerotic plaque development and was predominantly detected in macrophage-rich regions of advanced lesions. AAV-mediated circBRWD1 knockdown reduced aortic lesion size, plaque lipid accumulation, necrotic core area, TUNEL-positive signals and plaque-associated inflammatory markers in ApoE-/- mice. In RAW264.7 macrophages, circBRWD1 preferentially modulated pro-inflammatory responses, including iNOS, CD86, and pro-inflammatory cytokine expression. Mechanistically, circBRWD1 interacted with miR-141-5p and modulated miR-141-5p-mediated regulation of HMGB1 and downstream NF-κB-associated inflammatory signaling. These findings identify circBRWD1 as a potential regulator of atherosclerotic plaque progression and macrophage inflammatory responses, and support the involvement of the miR-141-5p/HMGB1/NF-κB regulatory relationship in these effects. circBRWD1 may therefore represent a potential target for modulating plaque-associated inflammation in atherosclerosis.