Essential oil from Fructus Alpinia zerumbet ameliorates atherosclerosis by activating PPARγ-LXRα-ABCA1/G1 signaling pathway

Background: Atherosclerosis (AS) is a progressive chronic disease. Currently, cardiovascular diseases (CVDs) caused by AS is responsible for the global increased mortality. Yanshanjiang as miao herb in Guizhou of China is the dried and ripe fruit of Fructus Alpinia zerumbet. Accumulated evidences have confirmed that Yanshanjiang could ameliorate CVDs, including AS. Nevertheless, its effect and mechanism on AS are still largely unknown. Purpose: To investigate the role of essential oil from Fructus Alpinia zerumbet (EOFAZ) on AS, and the potential mechanism. Methods: A high-fat diet (HFD) ApoE(-/-) mice model of AS and a oxLDL-induced model of macrophage-derived foam cells (MFCs) were reproduced to investigate the pharmacological properties of EOFAZ on AS in vivo and foam cell formation in vitro, respectively. The underlying mechanisms of EOFAZ were investigated using Network pharmacology and molecular docking. EOFAZ effect on PPAR gamma protein stability was measured using a cellular thermal shift assay (CETSA). Pharmacological agonists and inhibitors and gene interventions were employed for clarifying EOFAZ's potential mechanism. Results: EOFAZ attenuated AS progression in HFD ApoE(-/-) mice. This attenuation was manifested by the reduced aortic intima plaque development, increased collagen content in aortic plaques, notable improvement in lipid profiles, and decreased levels of inflammatory factors. Moreover, EOFAZ inhibited the formation of MFCs by enhancing cholesterol efflux through activiting the PPAR gamma-LXR alpha-ABCA1/G1 pathway. Interestingly, the pharmacological knockdown of PPAR gamma impaired the beneficial effects of EOFAZ on MFCs. Additionally, our results indicated that EOFAZ reduced the ubiquitination degradation of PPAR gamma, and the chemical composition of EOFAZ directly bound to the PPAR gamma protein, thereby increasing its stability. Finally, PPAR gamma knockdown mitigated the protective effects of EOFAZ on AS in HFD ApoE(-/-) mice. Conclusion: These findings represent the first confirmation of EOFAZ's in vivo anti-atherosclerotic effects in ApoE(-/-) mice. Mechanistically, its chemical constituents can directly bind to PPAR gamma protein, enhancing its stability, while reducing PPAR gamma ubiquitination degradation, thereby inhibiting foam cell formation via activation of the PPAR gamma-LXR alpha-ABCA1/G1 pathway. Simultaneously, EOFAZ could ameliorates blood lipid metabolism and inflammatory microenvironment, thus synergistically exerting its anti-atherosclerotic effects.