Common and specific downstream signaling targets controlled by Tlr2 and Tlr5 innate immune signaling in zebrafish

Abstract

BackgroundAlthough 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.ResultsWe 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.ConclusionsOur 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1740-9) contains supplementary material, which is available to authorized users.

Two highly adhesive lactic acid bacteria strains are protective in zebrafish infected with Aeromonas hydrophila by evocation of gut mucosal immunity

“…Therefore, studies on this topic using a wide range of potential probiotic micro-organisms in an appropriate model should be further encouraged. As an alternative model for understanding immune system function, zebrafish has been adopted to study the relationship between immunity and diseases/infection (Fehr et al 2015;Shan et al 2015;Yang et al 2015;Yoon et al 2015). Thus, in the present work, we demonstrated the protective role played by probiotic LAB strains against Aer.…”

Differential analyses for RNA-seq: transcript-level estimates improve gene-level inferences

“…Throughout this manuscript, we utilize two simulated data sets and four experimental data sets (Bottomly 14 [ Data set 3], GSE64570 15 [ Data set 4], GSE69244 16 [ Data set 5], GSE72165 17 [ Data set 6], see Supplementary File 1 for further details) for illustration. Details on the data generation and full records of the analyses are provided in the data sets and Supplementary File 1.…”

Pattern recognition receptors in zebrafish provide functional and evolutionary insight into innate immune signaling pathways

“…For example, TLR2 can form heterodimers that are responsible for the recognition of bacterial lipoproteins/lipopeptides or Pam3CSk4. 20, 33 TLR3, -5 and -9 recognize dsRNA, flagellin and unmethylated CpG DNA, respectively. 11, 13, 16, 34, 35 However, zebrafish TLR4 is not responsive to LPS stimulation, despite the fact that MD1 and Rp105, which mediate ligand delivery and/or recognition, have been identified.…”