title: TLR2 and TLR4 co-activation utilizes distinct signaling pathways for the production of Th1/Th2/Th17 cytokines in neonatal immune cells.
abstract: Co-activation of TLR2 and TLR4 by gram negative and gram positive bacterial ligands induces a robust pro-inflammatory response in inflammatory cells. In order to understand the signaling mechanism, we aimed to delineate the signaling molecules involved in TLR2 and TLR4 co-activation in neonatal immune cells for the production of Th1/Th2/Th17 inflammatory cytokines. For this, we pretreated cord blood and peripheral blood mononuclear and human mast cells with specific signaling molecule inhibitors such as BAY117082, PD98059 and LY294002 and then stimulated with LPS and PGN and assayed for cytokines IL-6, IL-12/IL-23p40 (Th1), IL-13 (Th2), IL-23 (Th17) and RANTES secretion. We found that upon co-stimulation the phosphorylation of NFκBp65, ERK1/2 and Akt was found to be higher than when stimulated with individual ligands in CBMCs. Also, when compared to adult cells, neonatal cells were more potent in the activation of ERK and Akt through TLR2 and TLR4 co-activation. In addition, neonatal cells possess similar capacity to activate NFκB as that of adult cells for IL-6 secretion. Furthermore, all three signaling molecules were found to be involved in the production of Th17 cytokines which is detrimental during inflammation induced by infection in neonates whereas NFκB is mainly involved in the induction of pro-inflammatory response and Th2 cytokines production. In conclusion, different signaling molecules were utilized for the production of different cytokines in immune cells.
authors.affiliation: Dept of Biotechnology, School of Bio-engineering, SRM University, Kattankulathur, Chennai 603203, India.
authors.forename: V
authors.initials: V
authors.lastname: Sugitharini
authors.affiliation: Dept of Biotechnology, School of Bio-engineering, SRM University, Kattankulathur, Chennai 603203, India.
authors.forename: P
authors.initials: P
authors.lastname: Shahana
authors.affiliation: Dept of Pediatrics, SRM Medical College Hospital and Research Centre, Kattankulathur, Chennai 603203, India.
authors.forename: A
authors.initials: A
authors.lastname: Prema
authors.affiliation: Dept of Biotechnology, School of Bio-engineering, SRM University, Kattankulathur, Chennai 603203, India. Electronic address: berlathagam.e@ktr.srmuniv.ac.in.
authors.forename: E
authors.initials: E
authors.lastname: Berla Thangam
mesh_terms: D002460:Cell Line; D016207:Cytokines / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D007249:Inflammation / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology; D016328:NF-kappa B / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D018417:Th1 Cells / Q000378:metabolism*; D058504:Th17 Cells / Q000378:metabolism*; D018418:Th2 Cells / Q000378:metabolism*; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D016328:NF-kappa B; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051057:Proto-Oncogene Proteins c-akt
keywords: Co-activation; Cytokines; Mast cells; Neonates; Signaling; TLR