To evaluate the role of nlrp3 inflammasome in acid aspiration mediated acute lung injury in mice

Abstract

Acute lung injury (ALI) is a pulmonary inflammatory disorder, manifested by recruitment of neutrophils and edema formation. NLRP3 inflammasome has been implicated during ALI but its role in acid aspiration mediated ALI remains largely unknown. Hence, the present study was designed to elucidate the role of NLRP3 inflammasome in acid aspiration (HCl) based mouse model of ALI and the involvement of oxidative stress in the process. In addition, the implication of NLRP3 inflammasome pathway was examined under conditions mimicking ALI exaggeration utilizing two-hit (HCl+LPS) induced mouse model of the disease. HCl-mediated ALI resulted in lung inflammation, as depicted by neutrophil in BALF, pulmonary edema and inflammasome activation (NLRP3/ASC/Caspase-1). Furthermore, acid instillation resulted in increased expression of NADPH oxidase subunits (gp91phox/gp22phox /gp67phox) as well as mitochondrial oxidative stress (mtROS/aconitase/succinate dehydrogenase). Interestingly, NADPH oxidase inhibitor, apocynin could not modulate HCl induced lung inflammation by much, while mito-tempo (mitochondrial-targeted antioxidant) significantly reduced lung inflammation, mitochondrial oxidative stress, phosphorylation of p65-NF-and#954;B (Ser 536) and NLRP3 inflammasome activation triggered by HCl. Next our data showed that MCC950 suppressed the lung inflammation and mitochondrial dysfunction along with attenuation of NLRP3 inflammasome activation upon two-hit mediated ALI. Furthermore, mito-tempo halted HCl+LPS mediated amplified NLRP3 release followed by amelioration of lungand#61538;inflammasome activation and IL-1 inflammation. Restoration of mitochondrial redox-balance by mito-tempo was B expression andand#61547;associated with blunted phosphorylation status of p65-NF- /IL-6). In light of our data, targetingand#61537;/TNF-and#61538;expression of its dependent genes (IL-1 mitochondrial oxidative stress-NLRP3 inflammasome axis might offer new treatment/preventive strategies against ALI. newline