title: Heparin-binding Hemagglutinin ofMycobacterium tuberculosisIs an Inhibitor of Autophagy.
abstract: Airway epithelial cell is often the initial site of attack by pathogens, and cell death is commonly caused by internalization ofMycobacterium tuberculosis(Mtb). However, the mechanism of interaction between epithelial cells andMtbis not well understood. In this study, we investigated the role of the heparin-binding hemagglutinin (HBHA) protein ofMtbin the function of epithelial cells. In particular, the autophagy of A549 cells was determined based on microtubule-associated protein 1 light chain 3 alpha (LC3) activity. Autophagosome formation was detected by Monodansylcadaverine (MDC) staining and immune fluorescence staining of LC3. Autophagy could be significantly suppressed by HBHA protein. In addition, the LDH assay results showed that HBHA treatment could induce death on A549 cells. To explore the form of cell death, we detected the activity of caspase-3 and LDH release of A549 cells in the presence or absence of caspase inhibitor Z-VAD-FMK. Results demonstrated that HBHA treatment could induce apoptosis of A549 cells. To further confirm these results, we constructed the recombinantMycobacterium smegmatis(MS) expressing HBHA (rMS-HBHA) and explored the influence ofrMS-HBHAon the function of A549 cells.rMS-HBHAinfection significantly inhibited LC3 expression and the maturation of autophagosomes in A549 cells. Subsequently, we infected A549 cells withMSand detected the viability of intracellularMSby CFU counts.rMS-HBHAshowed higher survival and replication capacity in A549 cells than those of the wild-typeMS. Finally, infection of A549 cells withrMS-HBHAcaused further apoptosis. These findings suggested thatrMS-HBHAcould inhibit autophagy, promote its survival and replication within A549 cells, and subsequently induce apoptosis on infected cells to facilitate infection.
authors.affiliation: Department of Clinical Laboratory, Xijing Hospital, Fourth Military Medical University Xi'an, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: Department of Pharmacology, School of Pharmacy, Fourth Military Medical University Xi'an, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Clinical Laboratory, Xijing Hospital, Fourth Military Medical University Xi'an, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Department of Clinical Laboratory, Xijing Hospital, Fourth Military Medical University Xi'an, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, Xijing Hospital, Fourth Military Medical University Xi'an, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Clinical Laboratory, Xijing Hospital, Fourth Military Medical University Xi'an, China.
authors.forename: Xiaorui
authors.initials: X
authors.lastname: Fu
authors.affiliation: Department of Clinical Laboratory, Xijing Hospital, Fourth Military Medical University Xi'an, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Clinical Laboratory, Xijing Hospital, Fourth Military Medical University Xi'an, China.
authors.forename: Yueyun
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Clinical Laboratory, Xijing Hospital, Fourth Military Medical University Xi'an, China.
authors.forename: Xiaoke
authors.initials: X
authors.lastname: Hao
mesh_terms: D000072283:A549 Cells; D000590:Amino Acid Chloromethyl Ketones / Q000037:antagonists & inhibitors; D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D002103:Cadaverine / Q000031:analogs & derivatives; D053148:Caspase 3 / Q000187:drug effects / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D015169:Colony Count, Microbial; D004847:Epithelial Cells / Q000382:microbiology; D004926:Escherichia coli / Q000235:genetics; D054884:Host-Pathogen Interactions / Q000502:physiology; D006801:Humans; D037102:Lectins / Q000037:antagonists & inhibitors*; D008565:Membrane Proteins / Q000494:pharmacology; D050296:Microbial Viability; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D020102:Mycobacterium smegmatis / Q000235:genetics / Q000276:immunology; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D011994:Recombinant Proteins; D037521:Virulence Factors
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D001426:Bacterial Proteins; C440647:HbhA protein, Mycobacterium tuberculosis; D037102:Lectins; C477012:MAP1LC3A protein, human; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D011994:Recombinant Proteins; D037521:Virulence Factors; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C104578:heparin-binding hemagglutinin; C505407:CASP3 protein, human; D053148:Caspase 3; C008542:monodansylcadaverine; D002103:Cadaverine
keywords: A549; HBHA; Mycobacterium smegmatis; Mycobacterium tuberculosis; apoptosis; autophagy