title: Mycobacterium bovisInduces Endoplasmic Reticulum Stress Mediated-Apoptosis by Activating IRF3 in a Murine Macrophage Cell Line.
abstract: Mycobacterium bovis (M. bovis) is highly adapted to macrophages and has developed multiple mechanisms to resist intracellular assaults. However, the host cells in turn deploy a multipronged defense mechanism to control bacterial infection. Endoplasmic reticulum (ER) stress-mediated apoptosis is one such primary defense mechanism. However, the role of interferon regulatory factor 3 (IRF3) between ER stress and apoptosis duringM. bovisinfection is unknown. Here, we demonstrate thatM. boviseffectively induced apoptosis in murine macrophages. Caspase-12, caspase-9, and caspase-3 were activated over a 48 h infection period. The splicing of XBP-1 mRNA and the level of phosphorylation of eIF2α, indicators of ER stress, significantly increased at early time points afterM. bovisinfection. The expansion of the ER compartment, a morphological hallmark of ER stress, was observed at 6 h. Pre-treatment of Raw 264.7 cells with 4-PBA (an ER stress-inhibitor) reduced the activation of the ER stress indicators, caspase activation and its downstream poly (ADP-ribose) polymerase (PARP) cleavage, phosphorylation of TBK1 and IRF3 and cytoplasmic co-localization of STING and TBK1.M. bovisinfection led to the interaction of activated IRF3 and cytoplasmic Bax leading to mitochondrial damage. Role of IRF3 in apoptosis was further confirmed by blocking this molecule with BX-795 that showed significant reduction expression of caspase-8 and caspase-3. Intracellular survival ofM. bovisincreased in response to 4-PBA and BX-795. These findings indicate that STING-TBK1-IRF3 pathway mediates a crosstalk between ER stress and apoptosis duringM. bovisinfection, which can effectively control intracellular bacteria.
authors.affiliation: State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University Beijing, China.
authors.forename: Yongyong
authors.initials: Y
authors.lastname: Cui
authors.affiliation: State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University Beijing, China.
authors.forename: Deming
authors.initials: D
authors.lastname: Zhao
authors.affiliation: Veterinary Population Medicine Department, College of Veterinary Medicine, University of Minnesota St. Paul, MN, USA.
authors.forename: Srinand
authors.initials: S
authors.lastname: Sreevatsan
authors.affiliation: State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University Beijing, China.
authors.forename: Chunfa
authors.initials: C
authors.lastname: Liu
authors.affiliation: State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.affiliation: State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University Beijing, China.
authors.forename: Zhiqi
authors.initials: Z
authors.lastname: Song
authors.affiliation: State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University Beijing, China.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Yang
authors.affiliation: School of Veterinary Medicine, University of Nottingham Sutton Bonington, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Barrow
authors.affiliation: State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University Beijing, China.
authors.forename: Xiangmei
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002082:Butylamines / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress / Q000502:physiology*; D050838:Interferon Regulatory Factor-3 / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism* / Q000382:microbiology; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D063306:Mitophagy / Q000187:drug effects; D009163:Mycobacterium bovis / Q000502:physiology*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology; D000067996:RAW 264.7 Cells; D013876:Thiophenes / Q000494:pharmacology; D014376:Tuberculosis / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D000071717:X-Box Binding Protein 1 / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D000099197:STING Protein
chemical_list: D002082:Butylamines; D020169:Caspases; D050838:Interferon Regulatory Factor-3; D008565:Membrane Proteins; D011065:Poly(ADP-ribose) Polymerases; D017346:Protein Serine-Threonine Kinases; D011743:Pyrimidines; D013876:Thiophenes; D000071717:X-Box Binding Protein 1; D051028:bcl-2-Associated X Protein; C121358:4-phenylbutylamine; C579675:BX795; C494827:Bax protein, mouse; C494233:Irf3 protein, mouse; C530855:Sting1 protein, mouse; D000099197:STING Protein; C000605544:Xbp1 protein, mouse; C498588:Tbk1 protein, mouse
keywords: ER stress; IRF3; M. bovis; apoptosis; mycobacterium