title: EBP50 induces apoptosis in macrophages by upregulating nitric oxide production to eliminate intracellular Mycobacterium tuberculosis.
abstract: Mycobacterium bovis BCG is known to have the capacity to inhibit the positioning of iNOS on BCG-containing phagosomes by interfering with EBP50, a scaffolding protein that controls the recruitment of inducible nitric oxide synthase (iNOS) at the vicinity of phagosomes in macrophages. However, knockdown of the expression of EBP50 still facilitates the intracellular survival of BCG, which suggested that EBP50 may have some other unknown antimycobacterial properties. In this study we show that overexpression of EBP50 by a recombinant lentivirus had no effect on the iNOS recruitment to M.tuberculosis-containing phagosomes, but significantly promoted the elimination of intracellular M.tuberculosis. We revealed in the present study that the enhancement of intracellular killing to M. tuberculosis upon EBP50 overexpression was due to the increased level of apoptosis in macrophages. We showed that EBP50 overexpression significantly increased the expression of iNOS and generation of nitric oxide (NO), and EBP50-induced apoptosis was NO-dependent and mediated by Bax and caspase-3. We found that M. tuberculosis decreases while Mycobacterium smegmatis increases the expression of EBP50 in RAW264.7 cells, which suggested that virulent mycobacteria are capable of modulating the antimycobacterial properties of macrophages by inhibiting the expression and interfering with the function of EBP50.
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
authors.forename: Yating
authors.initials: Y
authors.lastname: Deng
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
authors.forename: Zikun
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Luo
authors.affiliation: Department of Tuberculosis, Jiangxi Chest Hospital, Nanchang, 330006, China.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
authors.forename: Jianqing
authors.initials: J
authors.lastname: Ye
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
authors.forename: Junming
authors.initials: J
authors.lastname: Li
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D006801:Humans; D008264:Macrophages / Q000382:microbiology* / Q000502:physiology*; D051379:Mice; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D009569:Nitric Oxide / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010587:Phagocytosis / Q000276:immunology; D010588:Phagosomes / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics / Q000378:metabolism*; D014376:Tuberculosis / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D010750:Phosphoproteins; D017923:Sodium-Hydrogen Exchangers; D051028:bcl-2-Associated X Protein; C093376:sodium-hydrogen exchanger regulatory factor; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D053148:Caspase 3