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Epigenetic modification of TLRs in leukocytes is associated with increased susceptibility to Salmonella enteritidis in chickens.

Gou Z, Liu R, Zhao G, Zheng M, Li P, Wang H, Zhu Y, Chen J, Wen J - PLoS ONE (2012)

Bottom Line: Contrasting with the reduced expression of TLR genes, those of the zinc finger protein 493 (ZNF493) gene and Toll-interacting protein (TOLLIP) gene were enhanced in the susceptible chickens.Finally, the expression of TLR4 in peripheral blood mononuclear cells (PBMCs) infected in vitro with S. enteritidis increased significantly as a result of treatment with 5-Aza-2-deoxycytidine (5-Aza-dc) while either 5-Aza-dc or trichostatin A was effective in up-regulating the expression of TLR21 and TLR2-1.DNA methylation, in the predicted promoter region of TLR4 and TLR21 genes, and an exonic CpG island of the TLR2-1 gene was significantly higher in the susceptible chickens than in resistant chickens.

View Article: PubMed Central - PubMed

Affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Haidian, Beijing, China.

ABSTRACT
Toll-like receptors (TLRs) signaling pathways are the first lines in defense against Salmonella enteritidis (S. enteritidis) infection but the molecular mechanism underlying susceptibility to S. enteritidis infection in chicken remains unclear. SPF chickens injected with S. enteritidis were partitioned into two groups, one consisted of those from Salmonella-susceptible chickens (died within 5 d after injection, n = 6), the other consisted of six Salmonella-resistant chickens that survived for 15 d after injection. The present study shows that the bacterial load in susceptible chickens was significantly higher than that in resistant chickens and TLR4, TLR2-1 and TLR21 expression was strongly diminished in the leukocytes of susceptible chickens compared with those of resistant chickens. The induction of expression of pro-inflammatory cytokine genes, IL-6 and IFN-β, was greatly enhanced in the resistant but not in susceptible chickens. Contrasting with the reduced expression of TLR genes, those of the zinc finger protein 493 (ZNF493) gene and Toll-interacting protein (TOLLIP) gene were enhanced in the susceptible chickens. Finally, the expression of TLR4 in peripheral blood mononuclear cells (PBMCs) infected in vitro with S. enteritidis increased significantly as a result of treatment with 5-Aza-2-deoxycytidine (5-Aza-dc) while either 5-Aza-dc or trichostatin A was effective in up-regulating the expression of TLR21 and TLR2-1. DNA methylation, in the predicted promoter region of TLR4 and TLR21 genes, and an exonic CpG island of the TLR2-1 gene was significantly higher in the susceptible chickens than in resistant chickens. Taken together, the results demonstrate that ZNF493-related epigenetic modification in leukocytes probably accounts for increased susceptibility to S. enteritidis in chickens by diminishing the expression and response of TLR4, TLR21 and TLR2-1.

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DNA methyltransferase inhibitor 5-Aza-dc and/or the histone deacetylase inhibitor TSA increased TLR4, TLR21 and TLR2-1 expression.Peripheral blood mononuclear cells were inoculated with S. enteritidis without additions (controls) or in the presence of 5-Aza-dc, TSA or TSA plus 5-Aza-dc. Relative abundances of TLR4, TLR21 and TLR2-1 mRNA were analyzed by qPCR and normalized to β-actin mRNA. Data are means (n = 3) and comparisons were made to expression in the controls (-,-). The vertical bar is the SD from the error mean square of the ANOVA, * indicates P<0.05.
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pone-0033627-g004: DNA methyltransferase inhibitor 5-Aza-dc and/or the histone deacetylase inhibitor TSA increased TLR4, TLR21 and TLR2-1 expression.Peripheral blood mononuclear cells were inoculated with S. enteritidis without additions (controls) or in the presence of 5-Aza-dc, TSA or TSA plus 5-Aza-dc. Relative abundances of TLR4, TLR21 and TLR2-1 mRNA were analyzed by qPCR and normalized to β-actin mRNA. Data are means (n = 3) and comparisons were made to expression in the controls (-,-). The vertical bar is the SD from the error mean square of the ANOVA, * indicates P<0.05.

Mentions: The possibility that TLR4, TLR21 and TLR2-1 gene expression was regulated by epigenetic modification (histone acetylation and/or DNA methylation) in leukocytes infected with S. enteritidis was examined. Isolated PBMCs from SFP chickens were infected with S. enteritidis in the absence and presence of combinations of 5-Aza and TSA in the culture media. As shown in Fig. 4, 5-Aza-dc provoked a significant increase in TLR4 expression. Either 5-Aza-dc or TSA was effective in up-regulating the expression of TLR21 and TLR2-1; the effect of 5-Aza-dc was greater in the case of TLR21 and that of TSA was greater for TLR2-1. No cooperative effects of 5-Aza-dc and TSA on the expression of the genes were observed. These results indicate that histone acetylation and DNA methylation are involved in the repression of TLR4, TLR21 and TLR2-1 expression in PBMCs of chickens during S. enteritidis infection.


Epigenetic modification of TLRs in leukocytes is associated with increased susceptibility to Salmonella enteritidis in chickens.

Gou Z, Liu R, Zhao G, Zheng M, Li P, Wang H, Zhu Y, Chen J, Wen J - PLoS ONE (2012)

DNA methyltransferase inhibitor 5-Aza-dc and/or the histone deacetylase inhibitor TSA increased TLR4, TLR21 and TLR2-1 expression.Peripheral blood mononuclear cells were inoculated with S. enteritidis without additions (controls) or in the presence of 5-Aza-dc, TSA or TSA plus 5-Aza-dc. Relative abundances of TLR4, TLR21 and TLR2-1 mRNA were analyzed by qPCR and normalized to β-actin mRNA. Data are means (n = 3) and comparisons were made to expression in the controls (-,-). The vertical bar is the SD from the error mean square of the ANOVA, * indicates P<0.05.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3306431&req=5

pone-0033627-g004: DNA methyltransferase inhibitor 5-Aza-dc and/or the histone deacetylase inhibitor TSA increased TLR4, TLR21 and TLR2-1 expression.Peripheral blood mononuclear cells were inoculated with S. enteritidis without additions (controls) or in the presence of 5-Aza-dc, TSA or TSA plus 5-Aza-dc. Relative abundances of TLR4, TLR21 and TLR2-1 mRNA were analyzed by qPCR and normalized to β-actin mRNA. Data are means (n = 3) and comparisons were made to expression in the controls (-,-). The vertical bar is the SD from the error mean square of the ANOVA, * indicates P<0.05.
Mentions: The possibility that TLR4, TLR21 and TLR2-1 gene expression was regulated by epigenetic modification (histone acetylation and/or DNA methylation) in leukocytes infected with S. enteritidis was examined. Isolated PBMCs from SFP chickens were infected with S. enteritidis in the absence and presence of combinations of 5-Aza and TSA in the culture media. As shown in Fig. 4, 5-Aza-dc provoked a significant increase in TLR4 expression. Either 5-Aza-dc or TSA was effective in up-regulating the expression of TLR21 and TLR2-1; the effect of 5-Aza-dc was greater in the case of TLR21 and that of TSA was greater for TLR2-1. No cooperative effects of 5-Aza-dc and TSA on the expression of the genes were observed. These results indicate that histone acetylation and DNA methylation are involved in the repression of TLR4, TLR21 and TLR2-1 expression in PBMCs of chickens during S. enteritidis infection.

Bottom Line: Contrasting with the reduced expression of TLR genes, those of the zinc finger protein 493 (ZNF493) gene and Toll-interacting protein (TOLLIP) gene were enhanced in the susceptible chickens.Finally, the expression of TLR4 in peripheral blood mononuclear cells (PBMCs) infected in vitro with S. enteritidis increased significantly as a result of treatment with 5-Aza-2-deoxycytidine (5-Aza-dc) while either 5-Aza-dc or trichostatin A was effective in up-regulating the expression of TLR21 and TLR2-1.DNA methylation, in the predicted promoter region of TLR4 and TLR21 genes, and an exonic CpG island of the TLR2-1 gene was significantly higher in the susceptible chickens than in resistant chickens.

View Article: PubMed Central - PubMed

Affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Haidian, Beijing, China.

ABSTRACT
Toll-like receptors (TLRs) signaling pathways are the first lines in defense against Salmonella enteritidis (S. enteritidis) infection but the molecular mechanism underlying susceptibility to S. enteritidis infection in chicken remains unclear. SPF chickens injected with S. enteritidis were partitioned into two groups, one consisted of those from Salmonella-susceptible chickens (died within 5 d after injection, n = 6), the other consisted of six Salmonella-resistant chickens that survived for 15 d after injection. The present study shows that the bacterial load in susceptible chickens was significantly higher than that in resistant chickens and TLR4, TLR2-1 and TLR21 expression was strongly diminished in the leukocytes of susceptible chickens compared with those of resistant chickens. The induction of expression of pro-inflammatory cytokine genes, IL-6 and IFN-β, was greatly enhanced in the resistant but not in susceptible chickens. Contrasting with the reduced expression of TLR genes, those of the zinc finger protein 493 (ZNF493) gene and Toll-interacting protein (TOLLIP) gene were enhanced in the susceptible chickens. Finally, the expression of TLR4 in peripheral blood mononuclear cells (PBMCs) infected in vitro with S. enteritidis increased significantly as a result of treatment with 5-Aza-2-deoxycytidine (5-Aza-dc) while either 5-Aza-dc or trichostatin A was effective in up-regulating the expression of TLR21 and TLR2-1. DNA methylation, in the predicted promoter region of TLR4 and TLR21 genes, and an exonic CpG island of the TLR2-1 gene was significantly higher in the susceptible chickens than in resistant chickens. Taken together, the results demonstrate that ZNF493-related epigenetic modification in leukocytes probably accounts for increased susceptibility to S. enteritidis in chickens by diminishing the expression and response of TLR4, TLR21 and TLR2-1.

Show MeSH
Related in: MedlinePlus