Expression of the avian-specific toll-like receptor 15 in chicken heterophils is mediated by Gram-negative and Gram-positive bacteria, but not TLR agonists

Nerren, Jessica R.; He, Haiqi; Genovese, Kenneth J.; Kogut, Michael H.

doi:10.1016/j.vetimm.2010.02.017

Cited by 57 publications

(37 citation statements)

References 31 publications

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“…It is interesting that MDV, presumably recognized through its CpG motifs in its doublestranded DNA genome by TLR21 (which recognizes CpG in the chicken [5,25], rather than TLR9, which is absent), upregulates the expression of TLRs that recognize doublestranded RNA (TLR3) and bacterial cell surface components (TLR1B and TLR4). TLR15 is an avian-specific receptor and is of unknown function, although it is upregulated in response to Salmonella infection (20) and has been predicted to recognize a pathogen-surface PAMP (37).…”

Section: Discussionmentioning

confidence: 99%

Systems Analysis of Immune Responses in Marek's Disease Virus-Infected Chickens Identifies a Gene Involved in Susceptibility and Highlights a Possible Novel Pathogenicity Mechanism

Smith

Sadeyen

Paton

et al. 2011

J Virol

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Marek's disease virus (MDV) is a highly contagious oncogenic alphaherpesvirus that causes disease that is both a cancer model and a continuing threat to the world's poultry industry. This comprehensive gene expression study analyzes the host response to infection in both resistant and susceptible lines of chickens and inherent expression differences between the two lines following the infection of the host. A novel pathogenicity mechanism, involving the downregulation of genes containing HIC1 transcription factor binding sites as early as 4 days postinfection, was suggested from this analysis. HIC1 drives antitumor mechanisms, suggesting that MDV infection switches off genes involved in antitumor regulation several days before the expression of the MDV oncogene meq. The comparison of the gene expression data to previous QTL data identified several genes as candidates for involvement in resistance to MD. One of these genes, IRG1, was confirmed by single nucleotide polymorphism analysis to be involved in susceptibility. Its precise mechanism remains to be elucidated, although the analysis of gene expression data suggests it has a role in apoptosis. Understanding which genes are involved in susceptibility/resistance to MD and defining the pathological mechanisms of the disease gives us a much greater ability to try to reduce the incidence of this virus, which is costly to the poultry industry in terms of both animal welfare and economics.

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Section: Discussionmentioning

confidence: 99%

Systems Analysis of Immune Responses in Marek's Disease Virus-Infected Chickens Identifies a Gene Involved in Susceptibility and Highlights a Possible Novel Pathogenicity Mechanism

Smith

Sadeyen

Paton

et al. 2011

J Virol

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“…In addition, chTLR15 was up-regulated in embryonic chicken fibroblasts after incubation with heatkilled Salmonella. Another study (Nerren et al 2010) reported chTLR15 to be up-regulated in heterophils by heatkilled Gram-negative or Gram-positive bacteria, but not by any of the known TLR agonists. Interestingly, heterophils isolated from broiler chickens with relative resistance to infection by Salmonella, Enterococcus, and Campylobacter demonstrated significantly more up-regulation of chTLR15 after stimulation with live Salmonella, when compared with heterophils isolated from a susceptible line of chickens (Nerren et al 2009), suggesting chTLR15 may play an important role in protection against bacterial infection.…”

Section: Tlr15mentioning

confidence: 97%

Avian toll-like receptors

2010

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Analysis of the genomes of two distantly related bird species, chicken and zebra finch (divergence of about 100 million years), indicate that there are ten avian toll-like receptors and that five of these, TLR2a, 2b, 3, 4, 5 and 7, are clear orthologs to TLRs found in mammals. Duplication of genes has led to TLR1La and 1Lb, TLR2a and 2b, and two TLR7s in the zebra finch. Avian TLR21 may be orthologous to TLR21 found in fish and amphibians, and avian TLR15, which is phylogenetically related to the TLR2 family, appears to be unique to avian species. While TLR2 is conserved between mammalian and avian species, the other TLR2 family members evolved independently. Dimerization between either of the two avian TLR2 species and TLR1La or 1Lb permits recognition of the same broad range of molecules as recognized by mammalian TLR2 dimerized with either TLR1, 6 and 10. Similarly, while TLR9 has been lost from the avian genome, DNA high in unmethylated CpG motifs is immunostimulatory through avian TLR21 which is absent in mammals. Thus, while some TLR members were commonly retained in both mammals and birds, others were separately lost or gained, or diverged independently; but broadly speaking the TLRs of the two classes of vertebrates evolved to recognize very similar spectra of microbial products. Components of downstream TLR signaling are also mostly conserved but with some losses in avian species; notably, TRAM is absent in avian genomes and, hence, the TRIF/TRAM-dependent signaling pathway utilized by mammals in LPS activation appears to be absent in birds.

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“…Chicken TLRs are important in the recognition of PAMPs to induce the production of pro-inflammatory cytokines and antimicrobial peptides and to upregulate the expression of co-stimulatory molecules that may initiate adaptive immunity responses (Werling and Jungi, 2003;Yoshimura, 2015). Among these TLRs, TLR4 recognizes lipopolysaccharides (LPS) from Gram-negative bacteria, whereas it requires CD14 to accept the complex of LPS and LPS binding protein (Nerren et al, 2010;de Zoete et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Effects of Probiotics on the Expression of Cathelicidins in Response to Stimulation by <i>Salmonella Minnesota </i>Lipopolysaccharides in the Proventriculus and Cecum of Broiler Chicks

2016

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The aim of this study was to determine whether probiotic-feeding affected the expression of cathelicidins (CATHs), a major family of antimicrobial peptides, in response to lipopolysaccharides (LPS) challenge in the proventriculus and cecum of broiler chicks. One-day-old male Chunky broiler chicks were fed with or without 0.4% probiotics for 7 days (P-group and non-P-group, respectively). Then, they were orally challenged with no LPS (0-LPS), 1 μg LPS (1-LPS), or 100 μg LPS (100-LPS) (n＝5 in all groups) in Experiment 1, and with no LPS or 1 μg LPS (n＝6 in all groups) in Experiment 2. Five hours after LPS challenge, the proventriculi and ceca were collected to analyze CATHs expression. Expression of CATHs was examined at first by reverse transcription-polymerase chain reaction (RT-PCR) using the 0-LPS chicks of non-P-group. The differences in CATHs expression upon probioticsfeeding and LPS were analyzed by real time-PCR. All four CATHs (CATH1, 2, 3 and 4) were expressed in the proventriculus and cecum of chicks. In the proventriculus, the expression of CATHs after LPS challenge did not show significant differences between non-P and P-groups in Experiment 1 and 2. In the cecum, the interactions of the effects of probiotics and LPS on the expression of CATH2 in Experiment 1 and CATH1 and 2 in Experiment 2 were significant, and their expression in 1-LPS chicks was higher in P-group than in non-P-group. However, CATH3 and 4 did not show any significant differences between non-P-and P-groups challenged with LPS. These results suggest that probiotics-feeding may stimulate the immunodefense system mediated by CATH2 and possibly CATH1 against infection by Gram-negative bacteria in the cecum.

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Expression of the avian-specific toll-like receptor 15 in chicken heterophils is mediated by Gram-negative and Gram-positive bacteria, but not TLR agonists

Cited by 57 publications

References 31 publications

Systems Analysis of Immune Responses in Marek's Disease Virus-Infected Chickens Identifies a Gene Involved in Susceptibility and Highlights a Possible Novel Pathogenicity Mechanism

Systems Analysis of Immune Responses in Marek's Disease Virus-Infected Chickens Identifies a Gene Involved in Susceptibility and Highlights a Possible Novel Pathogenicity Mechanism

Avian toll-like receptors

Effects of Probiotics on the Expression of Cathelicidins in Response to Stimulation by <i>Salmonella Minnesota </i>Lipopolysaccharides in the Proventriculus and Cecum of Broiler Chicks

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