Activation of phosphatidylinositol 3-kinase and c-Jun-N-terminal kinase cascades enhances NF-kappaB-dependent gene transcription in BCG-stimulated macrophages through promotion of p65/p300 binding.
The proinflammatory response of infected macrophages is an important early host defense mechanism against mycobacterial infection. Mycobacteria have been demonstrated to induce proinflammatory gene transcription through the Toll-like receptors, (TLR)2 and TLR 4, which initiate signaling cascades leading to nuclear factor (NF)-kappaB activation. The main transduction pathway responsible for NF-kappaB activation has been established and involves the MyD88, interleukin-1 receptor-associated kinase, tumor necrosis factor receptor-associated factor-6, NF-kappaB-inducing kinase, and inhibitor of kappaB kinase complex. The role of other kinase cascades triggered by mycobacteria in the NF-kappaB activation is less clear. We herein examine the role of the mitogen-activated protein kinases (MAPKs) and phosphatidylinositol 3-kinase (PI-3K) cascades in the expression of the bacillus Calmette-Guerin (BCG) mycobacteria-induced NF-kappaB-dependent genes, macrophage-inflammatory protein-2 (MIP-2) and inducible nitric oxide (NO) synthase. Specific pharmacological inhibition of the PI-3K, c-jun-N-terminal kinase (JNK), and to a smaller extent, p38 MAPK but not extracellular-regulated kinase (ERK), suppressed NF-kappaB-dependent reporter gene transcription and MIP-2 and NO secretion in BCG-induced RAW264.7 macrophages. A similar effect was obtained following molecular inhibition of JNK via JNK-interacting protein-1 overexpression. In addition, a kinase-dead mutant of MEK kinase-1, the up-stream regulator of JNK, also proved to be a potent inhibitor of NF-kappaB-reporter activity. The effect of inhibitors was mediated by the down-regulation of NF-kappaB transcription activity and without effecting its nuclear translocation. These data suggest an indirect mechanism of the NF-kappaB regulation by these kinases, probably through p65 phosphorylation and improved binding to the p300 transcription coactivator. The data obtained demonstrate that PI-3K, JNK, and p38 MAPK activation by mycobacteria enhance NF-kappaB-driven gene expression contributing to the proinflammatory macrophage response.
Darieva
Zoulfia
Z
Laboratóire de Biologia do Reconhecer, Universisade Estadual do Norte Fluminense, Campos, Rio de Janeiro, Brazil.
Lasunskaia
Elena B
EB
Campos
Mariana N N
MN
Kipnis
Thereza L
TL
Da Silva
Wilmar D
WD
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites / Q000187:drug effects / Q000502:physiology; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D054426:Chemokine CXCL2; D018925:Chemokines / Q000037:antagonists & inhibitors / Q000378:metabolism; D050881:E1A-Associated p300 Protein; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000235:genetics; D007249:Inflammation / Q000201:enzymology / Q000235:genetics; D048031:JNK Mitogen-Activated Protein Kinases; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D008264:Macrophages / Q000187:drug effects / Q000382:microbiology / Q000502:physiology*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009163:Mycobacterium bovis / Q000276:immunology*; D016328:NF-kappa B / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009687:Nuclear Proteins / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D015534:Trans-Activators / Q000378:metabolism*; D051996:Transcription Factor RelA; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D054426:Chemokine CXCL2; D018925:Chemokines; C404915:Cxcl2 protein, mouse; D004791:Enzyme Inhibitors; C490665:Mapk8ip protein, mouse; D016328:NF-kappa B; D009687:Nuclear Proteins; D015534:Trans-Activators; D051996:Transcription Factor RelA; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D050881:E1A-Associated p300 Protein; C494361:Ep300 protein, mouse; D019869:Phosphatidylinositol 3-Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases