ATP/P2X7-NLRP3 axis of dendritic cells participates in the regulation of airway inflammation and hyper-responsiveness in asthma by mediating HMGB1 expression and secretion

The ATP/P2X7 axis of dendritic cells (DCs) mediates the activation of NLRP3 inflammasome and promotes secretion of interleukin (IL)-1β and IL-18 to induce T helper (Th) 2, Th17 differentiation in the pathogenesis of asthma. NLRP3 inflammasome also regulates high mobility protein 1 (HMGB1) release in DCs. Recent studies demonstrated the correlation between HMGB1 expression and airway inflammation and hyper-responsiveness (AHR) in asthma. However, the relationship between the ATP/P2X7-NLRP3 axis and HMGB1 in DCs in asthma is still unclear. ATP, apyrase, Brilliant Blue G, BzATP, glibenclamide, and Z-YVAD-FMK were administered to ovalbumin (OVA)-induced murine asthmatic model. For in vitro studies, bone marrow-derived mononuclear cells (BMDCs) were primed with LPS and stimulated with the same reagents. Activation of the ATP/P2X7 axis aggravated airway inflammation and AHR in the lung and induced Th2, Th17 polarization in asthmatic mice. Inhibition of NLRP3 inflammasome weakened cardinal features of asthma and blocked Th2, Th17 polarization. In vitro and vivo, ATP/P2X7 axis activated NLRP3 inflammasome and induced HMGB1 expression and release from DCs. Inhibition of NLRP3 inflammasome reduced HMGB1 expression and release. The ATP/P2X7-NLRP3 axis of DCs participates in mediating airway inflammation, AHR, and promoting Th2, Th17 inflammatory responses in asthmatic mice by inducing HMGB1 expression and secretion.