The selective NLRP3 inhibitor MCC950 hinders atherosclerosis development by attenuating inflammation and pyroptosis in macrophages

Wenyun Zeng,Xijuan Jiang,Bin Yu,Yanrong Suo,Danbin Wu,Miao Zeng,Qun Yu,Yijing Wang,Yingxin Sun,Qing Gao

doi:10.1038/s41598-021-98437-3

Abstract

NLRP3 inflammasome is a vital player in macrophages pyroptosis, which is a type of proinflammatory cell-death and takes part in the pathogenesis of atherosclerosis. In this study, we used apoE−/− mice and ox-LDL induced THP-1 derived macrophages to explore the mechanisms of MCC950, a selective NLRP3 inhibitor in treating atherosclerosis. For the in vivo study, MCC950 was intraperitoneal injected to 8-week-old apoE−/− mice fed with high-fat diet for 12 weeks. For the in vitro study, THP-1 derived macrophages were treated with ox-LDL and MCC950 for 48 h. MCC950 administration reduced plaque areas and macrophages contents, but did not improve the serum lipid profiles in aortic root of apoE−/− mice. MCC950 inhibited the activation of NLRP3/ASC/Caspase-1/GSDMD-N axis, and alleviated macrophages pyroptosis and the production of IL-1β and IL-18 both in aorta and in cell lysates. However, MCC950 did not affect the expression of TLR4 or the mRNA levels of NLRP3 inflammasome and its downstream proteins, suggesting that MCC950 had no effects on the priming of NLRP3 inflammasome activation in macrophages. The anti-atherosclerotic mechanisms of MCC950 on attenuating macrophages inflammation and pyroptosis involved in inhibiting the assembly and activation of NLRP3 inflammasome, rather than interrupting its priming.

Highlights

Abbreviations AIM2 Absent in melanoma 2 AS Atherosclerosis ApoE−/− Apolipoprotein E knockout ASC Apoptosis-associated speck-like protein containing a CARD Caspases Cysteinyl aspartate specific proteinases fetal bovine serum (FBS) Fetal bovine serum GM-CSF Granulocyte–macrophage colony stimulating factor GSDMD Gasdermin D GSDMD-N Amino terminal GSDMD HDL-C High density lipoprotein-cholesterol HFD High fat diet IFN-γ Interferon-gamma IL-1β Interleukin-1β IL-6 Interleukin-6
The NLRP3 inflammasome consisted of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC) and Caspase‐1, which can be activated by either pattern-associated molecular patterns (PAMPs), such as lipopolysaccharide or damageassociated molecular patterns (DAMPs), such as ox-LDL, and cholesterol crystals e tc[3]
The subsequent activation step leads to NLRP3 inflammasome assembly that facilitates self-cleavage and activation of Caspase-1, which further accelerates the maturation of IL-1β and IL-18 precursors and cleaves Gasdermin D (GSDMD) into active form amino terminal GSDMD (GSDMD-N)[5]

Summary

Introduction

Abbreviations AIM2 Absent in melanoma 2 AS Atherosclerosis ApoE−/− Apolipoprotein E knockout ASC Apoptosis-associated speck-like protein containing a CARD Caspases Cysteinyl aspartate specific proteinases FBS Fetal bovine serum GM-CSF Granulocyte–macrophage colony stimulating factor GSDMD Gasdermin D GSDMD-N Amino terminal GSDMD HDL-C High density lipoprotein-cholesterol HFD High fat diet IFN-γ Interferon-gamma IL-1β Interleukin-1β IL-6 Interleukin-6. Macrophages largely accumulate in atherosclerotic lesions during inflammation, which is a major contributor to atherosclerosis development[12]. Accumulation of ox-LDL induces macrophages dysfunction which forms foam cells and production of pro-inflammatory c ytokines[13]. Ox-LDL can promote vascular inflammation via targeting TLR4 and induce the priming and activation of NLRP3 inflammasome in human m acrophages[14]. The aberrant activation of NLRP3 inflammasome and its consequent high circulating levels of IL-1β and IL-18 are associated with macrophages recruitment to aortic wall lesions, which in turn induce foam cells formation and plaque development[15]. What’s more, pyroptosis is involved in ox-LDL induced macrophage death through activating NLRP3 inflammasome which is important for the formation of necrotic core and plaque instability in advanced atherosclerotic lesions[16]. Inhibition of NLRP3 inflammasome in macrophages could exert potential therapeutic effect against atherosclerosis[18]

Methods

Results

Conclusion