title: Mycobacterium tuberculosis H37Rv induces monocytic release of interleukin-6 via activation of mitogen-activated protein kinases: inhibition by N-acetyl-L-cysteine.
abstract: The release of proinflammatory cytokines after mycobacterial infection is a host immune response that may be propitious or deleterious to the host. Elevated levels of interleukin (IL)-6 are present in plasma of patients with active tuberculosis infection. The aim of this study was to investigate the role of mitogen-activated protein kinases in the secretion of interleukin-6 in THP-1 cells and human primary monocytes that were infected with Mycobacterium tuberculosis H37Rv, and its regulation by N-acetyl-L-cysteine, a potential antimycobacterial agent. Exposure of THP-1 human monocytes to M. tuberculosis H37Rv induced rapidly, in a time-dependent manner, the phosphorylation of mitogen-activated protein kinase kinase 3/6 and p38 mitogen-activated protein kinase, accompanied by an upregulation of interleukin-6. Using highly specific inhibitors of mitogen-activated protein kinase kinase-1, p38 mitogen-activated protein kinase and nuclear factor-kappaB, we found that extracellular-signal regulated kinase 1/2, p38 mitogen-activated protein kinase and nuclear factor-kappaB were essential for M. tuberculosis H37Rv-induced interleukin-6 production in human primary monocytes. Pretreatment with N-acetyl-L-cysteine reduced, in a dose-dependent manner, M. tuberculosis H37Rv-induced activation of mitogen-activated protein kinase kinase 3/6 and interleukin-6 production in THP-1 cells.
authors.affiliation: Department of Immunology, Tuberculosis Research Centre, Chetput, Chennai, India.
authors.forename: Palaniappan
authors.initials: P
authors.lastname: Natarajan
authors.forename: Sujatha
authors.initials: S
authors.lastname: Narayanan
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D002478:Cells, Cultured; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009000:Monocytes / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology
chemical_list: D015850:Interleukin-6; D047428:Protein Kinase Inhibitors; D020928:Mitogen-Activated Protein Kinases; D000111:Acetylcysteine