MLN4924 inhibits macrophage foam cell formation by enhancing autophagy and regulating metabolic phenotype

MLN4924 is a novel small molecule inhibitor of neddylation. During clinical trials, it has demonstrated promising therapeutic efficacy in hematological malignancies, lung cancer, and colon cancer. MLN4924 possesses anti-inflammatory properties and promotes cardiomyocyte autophagy. Given that atherosclerosis is an inflammatory disease in which autophagy and cellular senescence are key factors, we hypothesize that MLN4924 may exert a regulatory effect on the progression of atherosclerosis, warranting further investigation. The formation of foam cells plays a critical role in the development of atherosclerosis. We evaluated the effects of MLN4924 on the mRNA and protein expressions of scavenger receptor genes in macrophages and genes associated with the senescence-associated secretory phenotype (SASP). Oil Red O staining, Dil-ox-LDL uptake staining and cellular β-galactosidase staining were employed to assess the impacts of MLN4924 on the transformation of macrophages into foam cells and the senescence of macrophages. LC3 immunofluorescence staining, RT-qPCR and western blot were utilized to detect the regulatory effects of MLN4924 on macrophage autophagy. RNA sequencing (RNA-seq) and untargeted metabolomics analysis was carried out to evaluate the regulatory effects of MLN4924 on the transcriptome of macrophages and key metabolites. Our findings indicate that MLN4924 significantly downregulates the expressions of scavenger receptors such as CD36, SR-A1, SR-B1, and LOX-1, while upregulating genes associated with cholesterol efflux, including ABCA1 and ABCG1. Additionally, MLN4924 inhibits macrophage senescence and suppresses the expressions of SASP factors. The mechanism by which MLN4924 exerts these effects likely involves enhancing autophagy, thereby mitigating atherosclerotic progression. Furthermore, we conducted transcriptomic and metabolomic analyses to explore the effects of MLN4924 on macrophage transcriptome and metabolic phenotypes. Pathway enrichment analyses reveal significant enrichment of differentially expressed genes in the PI3K-AKT signaling pathway. We confirmed that MLN4924 inhibits AKT phosphorylation, thereby suppressing its activation and further inhibits GSK-3β phosphorylation. Moreover, MLN4924 regulates the mRNA levels of multiple genes and modulates metabolite production. These findings demonstrate that MLN4924 could inhibit the formation of foam cells, justifying further in-depth research.