Drp1Promotes Macrophage Xenophagy Via The ROS/HIF-1α Pathway To Inhabite Mycobacterium Tuberculosis Infection

Background:TB is a contagious disease caused by infection with the human pathogen Mycobacterium tuberculosis(Mtb),which is transmitted by aerosol from the lungs of an infected person to other susceptible people,and Mtb infection causes granulomatous lesions and cavitary changes.The body fights pathogen infection through innate immunity and adaptive immune response,and the natural immune cells of the lungs,mainly macrophages,dendritic cells,monocytes and neutrophils,are prone to phagocytosis of Mtb.Macrophages inhibit Mtb growth through autophagy pathway,lysosomal defense,and release of antimicrobial effector molecules.Mitochondria in immune cells play a key role in immune defense and cellular metabolism,and mitochondrial dynamics(fusion and division)and mitochondrial phagocytosis and mitochondrial function are critical,in addition to mitochondrial dynamics affecting cellular immune regulation.Mitochondrial dynein Drp1 promotes mitochondrial division and plays an important role in mitochondrial dynamics and mitochondrial function,but the role of Drp1 in immunity against tuberculosis infection has not been reported.Therefore,in-depth study of the interaction between Drp1 and Mtb infection is of great significance for regulating the therapeutic mechanism of Mtb infection and TB.Methods:1.qRT-PCR and WB detect the expression of Drp1 in Mtb-infected mouse macrophage cells(BMDMs);2.WB and confocal detect mitochondrial protein and morphological changes after Mtb infection with macrophages;3.H37Rv CFU to detect the effect of Drp1 on the bactericidal effect of macrophages4.WB and confocal detect changes in LC3 protein expression and colocalization with Mtb after Mtb infection with macrophages;5.qRT-PCR,WB and Griess-Reagent-Sy stem to detect the effects of Drp1 on nitric oxide synthase expression and nitric oxide(NO)production in BMDMs infected with Mtb:ROS-Activity-Assay-Kit to detect ROS levels;6.WB,confocal and H37Rv CFU detected the effects of CCCP,3-MA.and Roxadustat on macrophage autophagy changes;7.WB,confocal,and H37Rv CFU detected the effect of Drp1 regulation of Parkin on macrophage autophagy changes.Results:1.1.MTB infection promotes mitochondrial division2.Drp1 inhibits Mtb survival in macrophages3.Drp1 promotes the formation of autophagy in macrophages4.CCCP promotes autophagy and restores autophagy flow5.3-MA restores autophagy6.Parkin is not involved in Drp1’s regulation of macrophage autophagy7.Drp1 promotes the production of ROS and NO8.Drp1 promotes macrophage autophagy via the ROS/HIF-1α pathwayConclusions:Mycobacterium tuberculosis promotes mitochondrial division protein expression and promotes mitochondrial division changes after infection with mouse macrophages,This project focuses on the promotion of the formation of macrophage autophagy by the mitochondrial division protein Drp1 through the HIF-1α pathway,as well as the production of ROS and NO,which inhibits the survival of Mycobacterium tuberculosis.In addition,the autophagy agonist CCCP can promote the formation of autophagy and autophagy flow in macrophages;The autophagy inhibitor 3-MA can restore macrophage autophagy.And Drp1 is not involved in Parkin’s regulation of macrophages.