Endothelial NLRP3 Inflammasome Activation and Enhanced Neointima Formation in Mice by Adipokine Visfatin

Abstract

Inflammasomes serve as an intracellular machinery to initiate inflammatory response to various danger signals. The present study tested whether an inflammasome centered on nucleotide oligomerization domain-like receptor protein 3 (NLRP3) triggers endothelial inflammatory response to adipokine visfatin, a major injurious adipokine during obesity. NLRP3 inflammasome components were abundantly expressed in cultured mouse microvascular endothelial cells, including NLRP3, apoptosis-associated speck-like protein, and caspase-1. These NLRP3 inflammasome molecules could be aggregated to form an inflammasome complex on stimulation of visfatin, as shown by fluorescence confocal microscopy and size exclusion chromatography. Correspondingly, visfatin significantly increased caspase-1 activity and IL-1β release in microvascular endothelial cells, indicating an activation of NLRP3 inflammasomes. In animal experiments, direct infusion of visfatin in mice with partially ligated left carotid artery were found to have significantly increased neointimal formation, which was correlated with increased NLRP3 inflammasome formation and IL-1β production in the intima. Further, visfatin-induced neointimal formation, endothelial inflammasome formation, and IL-1β production in mouse partially ligated left carotid artery were abolished by caspase-1 inhibition, local delivery of apoptosis-associated speck-like protein shRNA or deletion of the ASC gene. In conclusion, the formation and activation of NLRP3 inflammasomes by adipokine visfatin may be an important initiating mechanism to turn on the endothelial inflammatory response leading to arterial inflammation and endothelial dysfunction in mice during early stage obesity.

Coronary Endothelial Dysfunction Induced by Nucleotide Oligomerization Domain-Like Receptor Protein with Pyrin Domain Containing 3 Inflammasome Activation During Hypercholesterolemia: Beyond Inflammation

“…However, Nlrp3 gene deletion significantly reversed the cholesterol crystal-induced inhibition of NO production. This inhibitory action of cholesterol crystals is similar to that of visfatin, a known adipokine that produces ROS-dependent impairment on endothelial function and Nlrp3 inflammasome activation (44,46). Together, these data suggest that Nlrp3-dependent downregulation of eNOS activity is another contributing mechanism that is responsible for cholesterol crystal-induced decreases in NO bioavailability and subsequent endothelial dysfunction.…”

“…NADPH oxidase-derived ROS associated with ceramide-enriched membrane raft clustering (21,47,52) were found to primarily contribute to the death factor or adipokine visfatin-mediated endothelial dysfunction (13,17,46,48,52,53). We recently demonstrated that ROS is able to activate Nlrp3 inflammasomes in ECs (44). In this study, cholesterol crystals markedly increased endothelial O 2 -production; however, such O 2 -production was not affected by Nlrp3 gene silencing.…”

“…Caspase-1 was also demonstrated to promotes atherosclerosis in apolipoprotein E-null [Apoe( -/ -)] mice by enhancing the inflammatory status of the lesion through a mechanism likely involving activation of lesion-associated immune cells and expression of cytokines, including interferon-c and IL-1b (4,44). In addition to Nlrp3, Nlrp1 has also been implicated in the regulation of immune-inflammatory processes in arterial ECs, contributing to endothelial activation and vessel remodeling (3).…”

Xenobiotic Pregnane X Receptor (PXR) Regulates Innate Immunity via Activation of NLRP3 Inflammasome in Vascular Endothelial Cells

“…Both protective and adverse effects of NLRP3 have been shown in age-related macular degeneration, an eye condition with choroidal neovascularization (20,21). Excessive activation of NLRP3 in ECs by dyslipidemia, disturbed flow, and visfatin may contribute to the development of atherosclerosis and restenosis (22,23). In addition to NLRP3, other PPRs, including TLR-2, TLR-3, TLR-4, TLR-9, NOD1, and NLRP1, are also induced by PXR.…”

Caspase-1, but Not Caspase-3, Promotes Diabetic Nephropathy

“…8,9 For in vivo caspase-1 inhibition we used Z-WEHD-FMK (R&D Systems, 1 mg/kg body wt, ip, daily for 6 weeks) and for caspase-4/5 inhibition we used Ac-LEVD-CHO (Enzo Life Sciences, 1 mg/kg body wt, ip, daily for 6 weeks). 33 Caspase-1 and Caspase-3/7 Activity Assay…”