title: Common and specific downstream signaling targets controlled by Tlr2 and Tlr5 innate immune signaling in zebrafish.
abstract: BACKGROUND
  Although the responses to many pathogen associated molecular patterns (PAMPs) in cell cultures and extracted organs are well characterized, there is little known of transcriptome responses to PAMPs in whole organisms. To characterize this in detail, we have performed RNAseq analysis of responses of zebrafish embryos to injection of PAMPs in the caudal vein at one hour after exposure. We have compared two ligands that in mammals have been shown to specifically activate the TLR2 and TLR5 receptors: Pam3CSK4 and flagellin, respectively.
  
  
  RESULTS
  We identified a group of 80 common genes that respond with high stringency selection to stimulations with both PAMPs, which included several well-known immune marker genes such as il1b and tnfa. Surprisingly, we also identified sets of 48 and 42 genes that specifically respond to either Pam3CSK4 or flagellin, respectively, after a comparative filtering approach. Remarkably, in the Pam3CSK4 specific set, there was a set of transcription factors with more than 2 fold-change, as confirmed by qPCR analyses, including cebpb, fosb, nr4a1 and egr3. We also showed that the regulation of the Pam3CSK4 and flagellin specifically responding sets is inhibited by knockdown of tlr2 or tlr5, respectively.
  
  
  CONCLUSIONS
  Our studies show that Pam3CSK4 and flagellin can stimulate the Tlr2 and Tlr5 signaling pathways leading to common and specific responses in the zebrafish embryo system.
authors.affiliation: Institute of Biology, Leiden University, PO Box 9502, 2300 RA, Leiden, The Netherlands.
authors.forename: Shuxin
authors.initials: S
authors.lastname: Yang
authors.affiliation: ZF-screens BV, J. H. Oortweg 19, 2333 CH, Leiden, The Netherlands.|Present address: Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, 61231, Bad Nauheim, Germany.
authors.forename: Rubén
authors.initials: R
authors.lastname: Marín-Juez
authors.affiliation: Institute of Biology, Leiden University, PO Box 9502, 2300 RA, Leiden, The Netherlands.
authors.forename: Annemarie H
authors.initials: AH
authors.lastname: Meijer
authors.affiliation: Institute of Biology, Leiden University, PO Box 9502, 2300 RA, Leiden, The Netherlands. h.p.spaink@biology.leidenuniv.nl.
authors.forename: Herman P
authors.initials: HP
authors.lastname: Spaink
mesh_terms: D000818:Animals; D005408:Flagellin / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D007113:Immunity, Innate / Q000235:genetics*; D008024:Ligands; D055666:Lipopeptides / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D000069452:Pathogen-Associated Molecular Pattern Molecules / Q000008:administration & dosage*; D015398:Signal Transduction; D051195:Toll-Like Receptor 2 / Q000096:biosynthesis* / Q000235:genetics; D051198:Toll-Like Receptor 5 / Q000096:biosynthesis* / Q000235:genetics; D059467:Transcriptome / Q000235:genetics / Q000276:immunology; D015027:Zebrafish / Q000196:embryology / Q000235:genetics
chemical_list: D008024:Ligands; D055666:Lipopeptides; D016328:NF-kappa B; C508075:Pam(3)CSK(4) peptide; D000069452:Pathogen-Associated Molecular Pattern Molecules; D051195:Toll-Like Receptor 2; D051198:Toll-Like Receptor 5; D005408:Flagellin