Role of vitamin D-induced autophagy in macrophages against Mycobacter-ium tuberculosis / 中国免疫学杂志

ABSTRACT

Objective:To investigate the role of vitamin D-induced autophagy in macrophages against Mycobacterium tuberculosis(Mtb).Methods:Induce U937 cells to differentiate into macrophages with phagocytic capacity by phorbol 12-myristate 13-acetate(PMA).The cells were randomly divided into negative control group,vitamin D group,autophagy inhibitor(3-MA)+vitamin D group,positive control(rapamycin)group.Infect all groups with Mtb for 6 hours.In the 4th day after infection,the mRNA expressions of autophagy-related genes ATG5, Beclin-1 and LL-37, LC3B were determined by semi-quantitative RT-PCR.LC3B-Ⅱ+and/or Mycobacterium tuberculosis antigen 85A+( Ag85A+)-cells were counted by flow cytometry.Results:Compared with the control groups, the mRNA expressions of ATG5,Beclin-1,LL-37 and LC3B were enhanced(P<0.01),the numbers of LC3B-Ⅱ+-cells increased,the numbers of Ag85A+-cells decreased, and the numbers of LC3B-Ⅱ+-Ag85A--cells increased ( vitamin D group 38.0% vs negative control group1.08%).Compared with the vitamin D group,the mRNA expressions of ATG5,Beclin-1 and LC3B were suppressed in the autophagy inhibitor(3-MA)+Vitamin D group,the mRNA expressions of LL-37 were reduced,and 3-MA inhibited the expression of LC3B-Ⅱ in cells with inhibition of LC3B-Ⅱ+-Ag85A--cells increase as well.Conclusion: Vitamin D can induce macrophage autophagy and further contribute to scavenging Mycobacterium tuberculosis.