title: Role of TLR2- and TLR4-mediated signaling in Mycobacterium tuberculosis-induced macrophage death.
abstract: Infection of macrophages with Mycobacterium tuberculosis (Mtb) induces cell death by apoptosis or necrosis. TLRs 2 and 4 recognition of mycobacterial ligands has been independently associated to apoptosis induction. To try to understand the particular contribution of these receptors to apoptotic or necrotic signaling upon infection with live Mtb H37Rv, we used macrophage lines derived from wild-type or TLR2-, TLR4-, and MyD88-deficient mouse strains. Mtb-infection triggered apoptosis depending on a TLR2/TLR4/MyD88/p38/ERK/PI-3K/NF-kB pathway; however, necrosis was favored in absence of TLR4 signaling independently of p38, ERK1/2, PI-3K or NF-kappaB activity. In conclusion, our results indicate that cooperation between TLR2- and TLR4-dependent mediated signals play a critical role in macrophage apoptosis induced by Mtb and the TLR4-mediated signaling has important role in the maintenance of the balance between apoptotic vs. necrotic cell death induced by macrophage infection with Mtb.
authors.affiliation: Grupo de Inmunología Celular e Inmunogenética, Instituto de Investigaciones Médicas, Universidad de Antioquia, Medellín, Colombia; Centro Colombiano de Investigación en Tuberculosis (CCITB), Medellín, Colombia.
authors.forename: Dulfary
authors.initials: D
authors.lastname: Sánchez
authors.forename: Mauricio
authors.initials: M
authors.lastname: Rojas
authors.forename: Israel
authors.initials: I
authors.lastname: Hernández
authors.forename: Danuta
authors.initials: D
authors.lastname: Radzioch
authors.forename: Luis F
authors.initials: LF
authors.lastname: García
authors.forename: Luis F
authors.initials: LF
authors.lastname: Barrera
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002460:Cell Line; D005260:Female; D005434:Flow Cytometry; D054884:Host-Pathogen Interactions; D008264:Macrophages / Q000166:cytology / Q000378:metabolism / Q000382:microbiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000502:physiology*; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009336:Necrosis; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D019869:Phosphatidylinositol 3-Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases