iNOS regulates activation of the NLRP3 inflammasome through the sGC/cGMP/PKG/TACE/TNF-α axis in response to cigarette smoke resulting in aortic endothelial pyroptosis and vascular dysfunction

• Published in: International immunopharmacology Vol. 101; no. Pt B; p. 108334
• Main Authors: Liao, Ke, Lv, Ding-Yi, Yu, Hui-Lin, Chen, Hong, Luo, Su-Xin
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2021; Elsevier BV
• Subjects: ADAM17 Protein - metabolism; Animals; Aorta; Aorta - pathology; Caspase; Cell Line; Cell viability; Cigarette smoke; Cigarette Smoking - adverse effects; Cigarettes; Coronary vessels; Cyclic GMP; Cyclic GMP - metabolism; Cyclic GMP-Dependent Protein Kinases; Endothelial cells; Endothelial Cells - physiology; Exposure; Gene expression; Human aortic endothelial cells; Humans; IL-1β; Inflammasomes; Inflammasomes - metabolism; Inhibitors; iNOS; L-Lactate dehydrogenase; Lactate dehydrogenase; Lactic acid; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitric oxide; Nitric Oxide Synthase Type II - metabolism; Nitric-oxide synthase; NLR Family, Pyrin Domain-Containing 3 Protein - genetics; NLR Family, Pyrin Domain-Containing 3 Protein - metabolism; NLRP3; Pathogenesis; Pyroptosis; Scanning electron microscopy; Signal Transduction; Smoke; Soluble Guanylyl Cyclase - metabolism; Tumor Necrosis Factor-alpha - metabolism; Tumor necrosis factor-α; Vascular Diseases - immunology; Vascular injury; Western blotting; iNOS; NLRP3; Human aortic endothelial cells; Pyroptosis; Vascular injury; Cigarette smoke
• ISSN: 1567-5769; 1878-1705; 1878-1705
• DOI: 10.1016/j.intimp.2021.108334

•Cigarette smoke exposure induced aortic endothelial injured and aorta relaxation impaired.•iNOS knock out reversed cigarette smoke-induced aortic endothelial injured and aorta relaxation impaired .•NLRP3  knock out reversed the cigarette smoke-induced aortic endothelial injuredand aorta relaxation impaired.•Cigarette smoke extract induced the HAECs pyroptosis, which could be blocked by iNOS or NLRP3 inhibitor.•iNOS regulated the activity of the NLRP3 inflammasome in cigarette smoke-exposed mouse and HAECs.•TACE/TNF-a axis was involved in regulation of NLRP3 by iNOS may depend on the sGC/cGMP/PKG pathway. Cigarette smoke (CS) is associated with vascular injury and dysfunction, which may be mediated by iNOS and NLRP3. However, the exact mechanism is unknown. iNOS-knockout and NLRP3-knockout C57BL/6 mice were exposed to air or CS. The vascular structure was examined by hematoxylin-eosin staining. The vascular tension was measured by a vascular reactivity assay. The expression of iNOS, NLRP3, caspase-1p20, IL-1β and eNOS were measured by western blotting. Human aortic endothelial cells (HAECs) were exposed to L-NIL (iNOS inhibitor), MCC950 (NLRP3 inhibitor), ODQ (sGC inhibitor), KT5823 (PKG inhibitor) or TAPI-1 (TACE/ADAM17 inhibitor) for 1 h prior to cigarette smoke extract (CSE) treatment. The cell viability and lactate dehydrogenase activity were assessed and pyroptosis was determined by scanning electron microscopy. The mRNA expression of TNF-α, and protein expression of iNOS, active-TACE, NLRP3, caspase-1p20, IL-1β, and eNOS were measured. CS resulted in shrinkage of endothelial cells, impaired aorta relaxation, reduced eNOS expression, and induced expression of iNOS, NLRP3, caspase-1p20 and IL-1β, which could be prevented by knockdown of iNOS and NLRP3. CSE reduced cell viability, induced LDH release and pyroptosis, and promoted iNOS, NLRP3, caspase-1p20, and IL-1β expression and reduced eNOS reduction, which could be reversed by inhibition of iNOS or NLRP3 in HAECs. Altogether, activation of the NLRP3 inflammasome by iNOS in CS-exposed HAECs may be mediated by the sGC/cGMP/PKG/TACE/TNF- α pathway. These results link iNOS to NLRP3 in CSE-stimulated HAECs through the sGC/cGMP/PKG/TACE/TNF-α pathway. The findings identify a mechanism through which iNOS and NLRP3 contribute to the pathogenesis of CS-induced pyroptosis and impaired aorta relaxation in HAECs.