Abstract 2055: Pyruvic Carboxylase In Macrophages Aggravates Atherosclerosis By Regulating Metabolism Reprogramming To Promote Inflammatory Responses Through Hif-1 Signal Pathway

Background: Atherosclerotic patients exhibit abnormal glucose metabolism. Pyruvic carboxylase (PC) is a key enzyme in glucose metabolism which converts pyruvate into oxaloacetate, an intermediate reactant in both gluconeogenesis and tricarboxylic acid cycle. However, the role of PC in atherosclerosis remains unclear. Aims: We aimed to explore a potential target in macrophage metabolism for atherosclerosis treatment. Methods: We generated macrophage-specific PC knockout mice ( PC M KO ) by crossbreeding the PC fl/fl mice with L yz 2 -cre mice expressing Cre-recombinase in macrophages. Bone marrow transplantation was conducted to generate PC fl/fl / Apoe -/- and PC M KO / Apoe -/- chimaera. Mice were administered with AAV- PCSK9 DY followed by a 12-week high-fat diet (HFD) to induce atherosclerosis. Results: PC was upregulated in macrophages of human and mice with atherosclerosis. Macrophage-specific PC deficiency mitigated HFD-induced atherosclerotic lesions in both Apoe -/- mice and mice injected with AAV- PCSK9 DY . PC deletion reduced reactive oxygen species overproduction and mitochondrial damage in macrophages. Transcriptomics revealed that PC activated the HIF-1 signal pathway by initiating metabolic reprogramming in macrophages. By preventing HIF-1α from proteasome degradation, PC induced nuclear translocation of HIF-1α in atherosclerotic aortic roots. HIF-1α stabilizer, dimethyloxalylglycine, reversed the anti-inflammatory effect of PC in macrophages exposed to hypoxia, whereas the inhibition of HIF-1α impeded the transformation of pro-inflammatory macrophages to anti-inflammatory macrophages induced by PC overexpression. Dimethyloxalylglycine reversed the beneficial effects of macrophage PC deficiency on atherosclerosis. Conclusion: Macrophage PC aggravates atherosclerosis by regulating metabolic reprogramming, thereby promoting inflammatory responses in macrophages through HIF-1 signal pathway.