Effect And Underlying Mechanism Of Q-U50,488H On NLRP3 Inflammasome Of Macrophage

Background:Hypoxic pulmonary hypertension caused by long-term exposure to the hypoxic environments at high altitude is a common type of pulmonary hypertension.Hypoxic pulmonary hypertension is a chronic progressive disease,which is mainly manifested in the increase of pulmonary artery pressure and right ventricular hypertrophy.Severe cases may lead to right heart failure and be life-threatening.It’s well known that pulmonary vascular remodelling and vasoconstriction are two important pathophysiological links in HPH.Although the mechanism of HPH has not been fully clarified,pulmonary inflammation has been proved to be an important cause of pulmonary vasoconstriction and remodeling.Therefore,how to effectively suppress the pulmonary inflammation during HPH may provide a direction for the prevention and treatment of HPH.As one of the most important immune cells,macrophages play an important role in pulmonary inflammation by releasing a variety of pro-inflammatory and anti-inflammatory cytokines to affect immune homeostasis and inflammation.Studies have shown that NLRP3 inflammasomes that promote inflammation are mainly expressed in macrophages.When activated,they promote macrophages to synthesize and secrete IL-1β,mediate the inflammatory response of macrophages.It is well known that glycolysis is one of the ways in which cells produce energy.It’s also an important metabolic pathway for macrophages.When glycolysis is inhibited,many functions of macrophages,including phagocytosis of pathogens,infected cells or apoptotic cells,and secretion of pro-inflammatory cytokines are affected.Therefore,any regulatory measures that affect the glycolytic metabolism of macrophages may affect the occurrence of inflammatory responses in macrophages.κ-opioid receptor(κ-OR)is the main opioid receptor distributed in cardiopulmonary vessels.Previous studies of my research group have shown that activation of κ-OR mediates significant cardiovascular protection,and one of its mechanisms may be related to the inhibition of the inflammatory response caused by myocardial ischemia,however,the role of κ-OR in pulmonary inflammation in pulmonary hypertension is unclear.In this experiment,the role and mechanism of κ-OR in HPH pulmonary inflammatory and macrophage inflammatory response were investigated by constructing HPH animal model and macrophage inflammatory response model.Objectives:1.To explore whether Q-U50,488 H,a new κ-OR receptor agonist,activates κ-OR to improve pulmonary inflammation in HPH.2.To clarify the mechanism of activation of κ-OR by Q-U50,488 H improves pulmonary inflammation in HPH.Results:1.In vivo,Chronic hypoxia induced pulmonary hypertension in mice for 4 weeks,resulting in increased right ventricular pressure and right ventricular hypertrophy;fluorescence co-labeling showed macrophage infiltration around pulmonary vessels,synthesis and release of IL-1β,with pulmonary vascular remodeling and smooth muscle thickening;increased expression of NLRP3 inflammasome activation-related molecular proteins in lung tissue.However,the above effects were inhibited by Q-U50,488 H,a κ-OR agonist,and the effect of Q-U50,488 H was blocked by nor-BNI,a κ-OR antagonist.2.In vitro,LPS stimulation activated macrophage inflammation and activated NLRP3 inflammasome,and the expression levels of related molecular proteins and RNA increased;after LPS treatment,the content of lactic acid in the culture medium increased,the level of glycolysis of macrophages increased,and the expression of glycolysis rate-limiting enzyme PFKFB3 protein increased;Q-U50,488 H treatment inhibits the above effects,but the effect of Q-U50,488 H was blocked by nor-BNI.3.In vitro,down-regulation of PFKFB3 inhibited NLRP3 inflammasome activation,while overexpression of PFKFB3 blocked the effect of Q-U50,488 H.Conclusions:1.Activation of κ-OR by Q-U50,488 H improves pulmonary inflammation and inhibits the activation of NLRP3 inflammasome in hypoxic pulmonary hypertension.2.After activation of κ-OR,the glycolysis level of macrophages is suppressed by inhibiting the expression of glycolysis rate-limiting enzyme PFKFB3,which further inhibits the activation of macrophage NLRP3 inflammasome.