title: The IRAK-ERK-p67phox-Nox-2 axis mediates TLR4, 2-induced ROS production for IL-1β transcription and processing in monocytes.
abstract: In monocytic cells, Toll-like receptor 4 (TLR4)- and TLR2-induced reactive oxygen species (ROS) cause oxidative stress and inflammatory response; however, the mechanism is not well understood. The present study investigated the role of interleukin-1 receptor-associated kinase (IRAK), extracellular signal-regulated kinase (ERK), p67phox and Nox-2 in TLR4- and TLR2-induced ROS generation during interleukin-1 beta (IL-1β) transcription, processing, and secretion. An IRAK1/4 inhibitor, U0126, PD98059, an NADPH oxidase inhibitor (diphenyleneiodonium (DPI)), and a free radical scavenger (N-acetyl cysteine (NAC))-attenuated TLR4 (lipopolysaccharide (LPS))- and TLR2 (Pam3csk4)-induced ROS generation and IL-1β production in THP-1 and primary human monocytes. An IRAK1/4 inhibitor and siRNA-attenuated LPS- and Pam3csk4-induced ERK-IRAK1 association and ERK phosphorylation and activity. LPS and Pam3csk4 also induced IRAK1/4-, ERK- and ROS-dependent activation of activator protein-1 (AP-1), IL-1β transcription, and IL-1β processing because significant inhibition in AP-1 activity, IL-1β transcription, Pro- and mature IL-β expression, and caspase-1 activity was observed with PD98059, U0126, DPI, NAC, an IRAK1/4 inhibitor, tanshinone IIa, and IRAK1 siRNA treatment. IRAK-dependent ERK-p67phox interaction, p67phox translocation, and p67phox-Nox-2 interaction were observed. Nox-2 siRNA significantly reduced secreted IL-1β, IL-1β transcript, pro- and mature IL-1β expression, and caspase-1 activity indicating a role for Nox-2 in LPS- and Pam3csk4-induced IL-1β production, transcription, and processing. In the present study, we demonstrate that the TLR4- and TLR2-induced IRAK-ERK pathway cross-talks with p67phox-Nox-2 for ROS generation, thus regulating IL-1β transcription and processing in monocytic cells.
authors: Pharmacology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Sitapur Road, Jankipuram Extension, Lucknow 226031, Uttar Pradesh, India.
authors: Ankita
authors: A
authors: Singh
authors: Pharmacology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Sitapur Road, Jankipuram Extension, Lucknow 226031, Uttar Pradesh, India.
authors: Vishal
authors: V
authors: Singh
authors: Pharmacology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Sitapur Road, Jankipuram Extension, Lucknow 226031, Uttar Pradesh, India.
authors: Rajiv L
authors: RL
authors: Tiwari
authors: Department of Transfusion Medicine and Blood Bank, King George's Medical University, Lucknow, Uttar Pradesh, India.
authors: Tulika
authors: T
authors: Chandra
authors: Department of Pathology, King George's Medical University, Lucknow, Uttar Pradesh, India.
authors: Ashutosh
authors: A
authors: Kumar
authors: Pharmacology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Sitapur Road, Jankipuram Extension, Lucknow 226031, Uttar Pradesh, India.
authors: Madhu
authors: M
authors: Dikshit
authors: Pharmacology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Sitapur Road, Jankipuram Extension, Lucknow 226031, Uttar Pradesh, India.
authors: Manoj K
authors: MK
authors: Barthwal
mesh_terms: D002460:Cell Line; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006801:Humans; D053592:Interleukin-1 Receptor-Associated Kinases / Q000378:metabolism*; D053583:Interleukin-1beta / Q000235:genetics* / Q000378:metabolism; D055666:Lipopeptides / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D053583:Interleukin-1beta; D055666:Lipopeptides; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; C508075:Pam(3)CSK(4) peptide; D010750:Phosphoproteins; D017382:Reactive Oxygen Species; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D018808:Transcription Factor AP-1; C079789:neutrophil cytosol factor 67K; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C507768:IRAK1 protein, human; D053592:Interleukin-1 Receptor-Associated Kinases; D048049:Extracellular Signal-Regulated MAP Kinases