Background: The global population of older individuals is growing, and ageing is a key risk factor for atherosclerotic cardiovascular diseases. Abnormal accumulation of senescent cells can cause potentially deleterious effects on the organism with age. As a vital marker of cellular senescence, the senescence-associated secretory phenotype (SASP) is a novel mechanism to link cellular senescence with atherosclerosis. Main body: In this review, we concretely describe the characteristics of the SASP and its regulation mechanisms. Importantly, we provide novel perspectives on how the SASP can promote atherosclerosis. The SASP from different types of senescent cells have vital roles in atherosclerosis progression. As a significant mediator of the harmful effects of senescent cells, it can play a pro-atherogenic role by producing inflammation and immune dysfunction. Furthermore, the SASP can deliver senescence signals to the surrounding vascular cells, gradually contributing to the development of atherosclerosis. Finally, we focus on a variety of novel therapeutic strategies aimed to reduce the burden of atherosclerosis in elderly individuals by targeting senescent cells and inhibiting the regulatory mechanisms of the SASP. Conclusion: This review systematically summarizes the multiple roles of the SASP in atherosclerosis and can contribute to the exploration of new therapeutic opportunities.

NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation contributes to the progression of atherosclerosis, and autophagy inhibits inflammasome activation by targeting macrophages. We investigated whether fucoidan, a marine sulfated polysaccharide derived from brown seaweeds, could reduce NLRP3 inflammasome activation by enhancing sequestosome 1 (p62/SQSTM1)-dependent selective autophagy to alleviate atherosclerosis in high-fat-fed ApoE-/- mice with partial carotid ligation and differentiated THP-1 cells incubated with oxidized low-density lipoprotein (oxLDL). Fucoidan significantly ameliorated lipid accumulation, attenuated progression of carotid atherosclerotic plaques, deregulated the expression of NLRP3 inflammasome, autophagy receptor p62, and upregulated microtubule-associated protein light chain 3 (LC3)-II/I levels. Transmission electron microscopy and GFP-RFP-LC3 lentivirus transfection further demonstrated that fucoidan could activate autophagy. Mechanistically, fucoidan remarkably inhibited NLRP3 inflammasome activation, which was mostly dependent on autophagy. The inhibitory effects of fucoidan on NLRP3 inflammasome were enhanced by autophagy activator rapamycin (Rapa) and alleviated by autophagy inhibitor 3-methyladenine (3-MA). Fucoidan promoted the colocalization of NLRP3 and p62. Knockdown of p62 and ATG5 by small interfering RNA significantly reduced the inhibitory effects of fucoidan treatment on NLRP3 inflammasome. The data suggest that fucoidan can inhibit NLRP3 inflammasome activation by enhancing p62/SQSTM1-dependent selective autophagy to alleviate atherosclerosis.

Background: Nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome activation can induce the secretion of IL-1β and IL-18 and after promoting the development of atherosclerosis. MiR-155 is an important microRNA that modulates inflammation in atherosclerosis, but the role of miR-155 in the regulation of the NLRP3 inflammasome is still unknown. Methods: The atherosclerosis model was set up using ApoE^−/− mice, and the lentiviral vector (LV) was used to interfere the expression of miR-155. HE stains was used for plaque morphology, immunohistochemistry (IHC) and western blot were used for protein expression quantification. We used oxidized low-density lipoprotein (ox-LDL) to incubate PMA-preprocessed THP-1 macrophages and detected NLRP3 inflammasome activation and ERK1/2 phosphorylation by western blot and Enzyme-linked immunosorbent assay. Results: HE stains showed that the intravascular plaques in the miR-155-up group were remarkably increased, compared with negative control (NC) group. Results of IHC showed that the expression of caspase-1 and IL-1β in the miR-155-up group was the highest of four groups, consist with the Western blot analysis. The results of in vitro experiment show that ox-LDL promoted NLRP3 inflammasome activation and ERK1/2 phosphorylation. Blocking the ERK1/2 pathway could inhibit ox-LDL-induced NLRP3 inflammasome activation. Moreover, we found that the overexpression of miR-155 promoted the activation of the ox-LDL-induced NLRP3 inflammasome, which could also be blocked by the ERK inhibitor U0126. Conclusions: MiR-155 aggravates the carotid AS lesion in ApoE^−/− mice and exerts a regulatory effect on NLRP3 inflammasome activation in ox-LDL-induced macrophages via the ERK1/2 pathway.

Inflammation, especially involving the NLRP3 inflammasome, is critical to atherosclerotic plaque formation. Enhanced autophagy can inhibit the development of atherosclerosis, and recent studies have revealed that NLRP3 inflammasome can be degraded by autophagy in atherosclerosis. In the present study, we established a foam-cell model to investigate the impact of oxidized low density lipoproteins (ox-LDLs) on autophagy and the inflammasome in atherosclerosis-related inflammation. We observed that ox-LDLs activated NLRP3 inflammasomes in macrophages and restricted autophagy in a time-and dose-dependent manner. We further observed through immunoprecipitation and siRNA knockdown that autophagic degradation of the NLRP3 inflammasome is dependent on K63 polyubiquitation of its NLRP3 subunit and subsequent binding by the adaptor protein p62. Our findings uncover a mechanism by which autophagy inhibits inflammation in atherosclerosis and the role of K63 in that process.