SENP3 Deficiency Inhibits Atherosclerosis by Regulating TLR4/NF-κB and SOAT2

SUMOylation plays critical roles in both initiation and development of atherosclerosis. SUMO-specific protease 3 (SENP3), a SUMO-specific protease that targets SUMO2/3 for deSUMOylation, is involved in vascular remodeling and the modulation of macrophage functions. Here, we probed for the role of SENP3 in macrophages in the development of atherosclerosis. Stable and unstable plaques were collected from patients with atherosclerosis. A macrophage-specific SENP3 knockout mouse (Senp3^Mac-KO) was generated and performed for a murine atherosclerosis model. Transcriptional sequencing was performed to identify potential mechanisms. SENP3 expression in macrophages was increased in unstable plaques, compared to stable plaques. The mean fluorescence intensity of SENP3 in macrophages infiltrating carotid plaques was positively correlated with circulating pro-inflammatory cytokines, low density lipoprotein (LDL-C), and triglycerides in atherosclerosis patients. Senp3^Mac-KO mice exhibited a markedly reduced atherosclerotic plaque area in the aorta, compared to wild-type mice. Knockdown of SENP3 in macrophages resulted in decreased secretion of pro-inflammatory cytokines, increased secretion of anti-inflammatory factors, and reduced foam cell formation. Transcriptional analysis identified significant enrichment in Toll-like receptor (TLR4) signaling pathway modulated by SENP3. Genetic deletion of either TLR4 (Tlr4^-/-) or Sterol O-Acyltransferase 2 (SOAT2) (Soat2^-/-) attenuated the exacerbation of atherosclerosis development induced by SENP3 overexpression. Furthermore, SENP3 regulated TLR4 and SOAT2 expression indirectly via the transcription factor MYC rather than through direct deSUMOylation of TLR4 or SOAT2 themselves. Downregulation of SENP3 in macrophages suppresses pro-inflammatory cytokine release by inhibiting TLR4 signaling and reduces foam cell formation by impeding SOAT2 expression, both mediated by the transcription factor MYC, thereby attenuating the development of atherosclerosis. Hence, SENP3 may represent a potential therapeutic target in atherosclerosis.