NF-κB/ABCA1 pathway aggravates ox-LDL-induced cell pyroptosis by activation of NLRP3 inflammasomes in THP-1-derived macrophages

Objective: NF-κB (nuclear transcription factor-kappa B) plays a well-known function in the regulation of immune responses and inflammation, but growing evidences support a major role of it in atherosclerosis. Currently, the regulatory mechanism of NF-κB pathway involved in atherosclerosis remains unclear.

Methods: To investigate the role of ox-LDL (oxidized low-density lipoprotein) in NF-κB regulation, the protein expression of phosphorylated NF-κB, a marker of NF-κB pathway activation was measured. The pyroptosis of macrophage was evaluated by western blot and fluorescence microscope. Cholesterol efflux capacity was determined by fluorescence assay and oil red O staining. The inhibitor of activation of NF-κB signal was used to assess the effect of NF-κB signal on macrophage pyroptosis and cholesterol efflux in macrophage. Small interfering RNA of ABCA1 (cholesterol transporters ATP binding boxes A1) was used to assess the effect of ABCA1 on macrophage pyroptosis.

Results: In this study, we reported THP-1 derived macrophage can be stimulated to increase pyroptosis by ox-LDL in a concentration-dependent manner. Macrophage pyroptosis was correlated with enhanced activation of NF-κB signal. After using inhibitor of NF-κB phosphorylation to attenuate activation of NF-κB signal, we identified and confirmed the decrease of macrophage pyroptosis and the occurrence of ox-LDL-induced cholesterol efflux disorder. Furthermore, we found that the downregulation of ABCA1 led to increased cell inflammation death. But pyroptosis was blocked, may led to cholesterol efflux dysfunction.

Conclusion: Taken together, the present results indicate that the mechanism of NF-κB involved in the development of atherosclerosis depends on mediating cell pyroptosis and cholesterol efflux and provide significant light on macrophage NF-κB signal in atherosclerosis.