CD147 Sparks Atherosclerosis by Driving M1 Phenotype and Impairing Efferocytosis.

BACKGROUND: Atherosclerosis is a globally prevalent chronic inflammatory disease with high morbidity and mortality. The development of atherosclerotic lesions is determined by macrophages. This study aimed to investigate the specific role of myeloid-derived CD147 (cluster of differentiation 147) in atherosclerosis and its translational significance. METHODS AND RESULTS: We generated mice with a myeloid-specific knockout of CD147 and mice with restricted CD147 overexpression, both in an apoE-deficient (ApoE-/-) background. Here, the myeloid-specific deletion of CD147 ameliorated atherosclerosis and inflammation. Consistent with our in vivo data, macrophages isolated from myeloid-specific CD147 knockout mice exhibited a phenotype shift from proinflammatory to anti-inflammatory macrophage polarization in response to lipopolysaccharide/IFN (interferon)-γ. These macrophages demonstrated a weakened proinflammatory macrophage phenotype, characterized by reduced production of NO and reactive nitrogen species derived from iNOS (inducible NO synthase). Mechanistically, the TRAF6 (tumor necrosis factor receptor-associated factor 6)-IKK (inhibitor of κB kinase)-IRF5 (IFN regulatory factor 5) signaling pathway was essential for the effect of CD147 on proinflammatory responses. Consistent with the reduced size of the necrotic core, myeloid-specific CD147 deficiency diminished the susceptibility of iNOS-mediated late apoptosis, accompanied by enhanced efferocytotic capacity mediated by increased secretion of GAS6 (growth arrest-specific 6) in proinflammatory macrophages. These findings were consistent in a mouse model with myeloid-restricted overexpression of CD147. Furthermore, we developed a new atherosclerosis model in ApoE-/- mice with humanized CD147 transgenic expression and demonstrated that the administration of an anti-human CD147 antibody effectively suppressed atherosclerosis by targeting inflammation and efferocytosis. CONCLUSIONS: Myeloid CD147 plays a crucial role in the growth of plaques by promoting inflammation in a TRAF6-IKK-IRF5-dependent manner and inhibiting efferocytosis by suppressing GAS6 during proinflammatory conditions. Consequently, the use of anti-human CD147 antibodies presents a complementary therapeutic approach to the existing lipid-lowering strategies for treating atherosclerotic diseases.

UBE2S promotes glycolysis in hepatocellular carcinoma by enhancing E3 enzyme-independent polyubiquitination of VHL.

Background/Aims: Ubiquitination is widely involved in the progression of hepatocellular carcinoma (HCC) by regulating various cellular processes. However, systematic strategies for screening core ubiquitin-related genes, clarifying their functions and mechanisms, and ultimately developing potential therapeutics for patients with HCC are still lacking. Methods: Cox and LASSO regression analyses were performed to construct a ubiquitin-related gene prediction model for HCC. Loss- and gain-of-function studies, transcriptomic and metabolomics analysis were used to explore the function and mechanism of UBE2S on HCC cell glycolysis and growth. Results: Based on 1423 ubiquitin-related genes, a four-gene signature was successfully constructed to evaluate the prognosis of patients with HCC. UBE2S was identified in this signature with the potential to predict the survival of patients with HCC. E2F2 transcriptionally upregulated UBE2S expression by directly binding to its promoter. UBE2S positively regulated glycolysis in a HIF-1α-dependent manner, thus promoting the proliferation of HCC cells. Mechanistically, UBE2S enhanced K11-linkage polyubiquitination at lysine residues 171 and 196 of VHL independent of E3 ligase, thereby indirectly stabilizing HIF-1α protein levels by mediating the degradation of VHL by the proteasome. In particular, the combination of cephalomannine, a small molecule compound that inhibits the expression of UBE2S, and PX-478, an inhibitor of HIF-1α, significantly improved the anti-tumor efficacy. Conclusions: UBE2S is identified as a key biomarker in HCC among the thousands of ubiquitin-related genes and promotes glycolysis by E3 enzyme-independent ubiquitination, thus serving as a therapeutic target for the treatment of HCC.