Southern Plains Agricultural Research Center (SPARC), Agricultural Research Service (ARS), United States Department of Agriculture (USDA) , College Station, TX , USA.
Front Vet Sci. 2015 Sep 8;2:33. doi: 10.3389/fvets.2015.00033. eCollection 2015.
Non-typhoidal Salmonella enterica induce an early pro-inflammatory response in chickens. However, the response is short-lived, asymptomatic of disease, resulting in a persistent colonization of the ceca, and fecal shedding of bacteria. The underlying mechanisms that control this persistent infection of chickens by Salmonella are unknown. Recently, we found an expansion of the Treg population and subsequent increased in vitro immunosuppressive functions of the CD4(+)CD25(+) cells isolated from the ceca of the Salmonella-infected chickens by day 4 post-infection that increased steadily throughout the course of the 14 days of infection, whereas the number of CD4(+)CD25(+) cells in the non-infected controls remained steady throughout the study. CD4(+)CD25(+) cells from cecal tonsils of S. enteritidis-infected birds had greater expression of IL-10 mRNA content than the CD4(+)CD25(+) cells from the non-infected controls at all the time points studied. These results suggest the development of a tolerogenic immune response in the cecum of Salmonella-infected chickens may contribute to the persistance of Salmonella cecal colonization. Using a chicken-specific kinome peptide immune array, we have analyzed the signaling pathways altered during the establishment of this tolerogenic state. This analysis has revealed a role for the non-canonical Wnt signaling pathway in the cecum at 4 days post-infection. Infection induced the significant (p < 0.01) phosphorylation of the G-protein-coupled transmembrane protein, Frizzled 1 (FZD1), resulting in an influx of intracellular Ca(2+) and the phosphorylation of the Ca(2+)-dependent effector molecules calcium/calmodulin-dependent kinase II (CamKII), β-catenin, protein kinase C, and the activation of the transcription factor, NFAT. Nuclear translocation of NFAT resulted in a significant increase in the expression of the anti-inflammatory cytokines IL-10 and TGF-β. Increased expression of TGF-β4 mRNA activates the TGF-β signaling pathway that phosphorylates the receptor-activated Smads, Smad2 and Smad3. Combined with the results from our Treg studies, these studies describe kinome-based phenotypic changes in the cecum of chickens during Salmonella Enteritidis infection starting 4 days post-infection that leads to an anti-inflammatory, tolerogenic local environment, and results in the establishment of persistent intestinal colonization.
非伤寒沙门氏菌会引起鸡的早期促炎反应。然而，这种反应是短暂的，没有疾病症状，导致盲肠持续定植和细菌粪便排出。控制沙门氏菌持续感染鸡的潜在机制尚不清楚。最近，我们发现，在感染沙门氏菌后第 4 天，感染鸡盲肠中分离的 CD4+CD25+细胞的 Treg 群体扩张，体外免疫抑制功能随后增强，并且在感染的 14 天过程中持续稳定增加，而未感染对照组的 CD4+CD25+细胞数量在整个研究过程中保持稳定。在所有研究时间点，来自肠炎沙门氏菌感染鸟类的盲肠扁桃体的 CD4+CD25+细胞比非感染对照组的 CD4+CD25+细胞具有更高的 IL-10 mRNA 含量。这些结果表明，沙门氏菌感染鸡盲肠中耐受原性免疫反应的发展可能有助于沙门氏菌盲肠定植的持续存在。使用鸡特异性激酶组肽免疫阵列，我们分析了在建立这种耐受状态过程中改变的信号通路。这项分析表明，非经典 Wnt 信号通路在感染后 4 天的盲肠中起作用。感染诱导 G 蛋白偶联跨膜蛋白 Frizzled 1 (FZD1) 的显著（p < 0.01）磷酸化，导致细胞内 Ca2+内流和 Ca2+-依赖性效应分子钙/钙调蛋白依赖性激酶 II (CamKII)、β-连环蛋白、蛋白激酶 C 的磷酸化，以及转录因子 NFAT 的激活。NFAT 的核易位导致抗炎细胞因子 IL-10 和 TGF-β的表达显著增加。TGF-β4 mRNA 的表达增加激活 TGF-β 信号通路，磷酸化受体激活的 Smads，Smad2 和 Smad3。结合我们的 Treg 研究结果，这些研究描述了沙门氏菌感染后 4 天开始，沙门氏菌感染鸡盲肠中的激酶组表型变化，导致抗炎、耐受原性的局部环境，并导致持续的肠道定植。
