Regulation and Molecular Mechanism of TLR5 on Resistance to Escherichia coli F18 in Weaned Piglets
Regulation and Molecular Mechanism of TLR5 on Resistance to Escherichia coli F18 in Weaned Piglets
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TLR5对断奶仔猪抗大肠杆菌F18的调控及分子机制
DOI：
10.3390/ani9100735
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发表时间：
2019-10-01
期刊：
影响因子：
3
通讯作者：
Bao, Wenbin
中科院分区：
文献类型：
--
作者：
Dai, Chaohui;Yang, Li;Bao, Wenbin
仔猪腹泻是许多规模化养猪场最常见的疾病，造成严重的经济损失。滥用疫苗和兽药非常普遍，不仅导致耐药细菌的出现和流行，还导致畜产品质量和经济效益下降。因此，通过遗传手段提高仔猪对腹泻的抵抗力是现代育种科学家的共同目标。本研究旨在从表观遗传因素的角度揭示重要候选基因TLR5调控仔猪腹泻的分子机制。摘要Toll样受体5(TLR5)在免疫系统中起重要作用。在本研究中，我们对耐F18和敏感的苏台断奶仔猪的十二指肠进行了转录组学分析，并分析了TLR5的差异表达。以猪小肠上皮细胞系(IPEC-J2)为研究对象，研究了TLR5的细胞定位，以及TLR5的表达对IPEC-J2细胞侵袭的影响。结果表明，大肠杆菌F18敏感仔猪十二指肠和空肠组织中TLR5的表达水平显著高于耐药仔猪。TLR5蛋白主要表达于细胞质和细胞膜。与TLR5信号通路相关的基因在TLR5过表达细胞中的表达显著高于对照细胞。TLR5高表达细胞的细菌黏附率高于空白细胞，而TLR5干扰细胞的细菌黏附率低于空白细胞。TLR5的核心启动子区域包括两个CpG岛和16个作用元件。启动子区域第二个CpG岛上MC-6位点的甲基化对TLR5的表达有调节作用。因此，TLR5在大肠杆菌侵袭过程中起着重要的调节作用。TLR5的低表达抑制了免疫应答，减少了细胞损伤，有利于耐受大肠杆菌的刺激。综上所述，本研究初步揭示了TLR5基因调控仔猪对大肠杆菌抗性的分子机制，为筛选猪对大肠杆菌的抗性标记提供了新的候选基因。
Simple Summary Piglet diarrhea is the most common type of disease on many large-scale pig farms, where it causes serious economic losses. Abuses of vaccines and veterinary medicine are very common, which not only lead to the emergence and prevalence of drug-resistant bacteria, but also to a decline in the quality of livestock products and economic benefits. Therefore, improving the resistance of piglets to diarrhea by genetic means is a common goal of modern breeding scientists. This study aims to reveal the molecular mechanism of regulating piglet diarrhea via the important candidate gene TLR5 from the perspective of epigenetic factors. Abstract Toll-like receptor 5 (TLR5) plays an important role in immune system. In this study, we performed transcriptome analysis of the duodenum in E. coli F18-resistant and -sensitive Sutai weaned piglets and analyzed the differential expression of TLR5. The cellular localization of TLR5 was investigated, and the effect of TLR5 expression on E. coli invasion was evaluated after pig small intestinal epithelial cell lines (IPEC-J2) were stimulated by E. coli. The results showed that TLR5 expression level in duodenum and jejunum were significantly higher in E. coli F18-sensitive than in E. coli F18-resistant piglets. TLR5 protein was mainly expressed in the cytoplasm and cell membrane. The expression of genes associated with the TLR5 signaling pathway were significantly higher in TLR5-overexpressed cells than in control cells. Bacterial adhesion was higher in TLR5-overexpressed cells than in blank cells and lower in TLR5 interference than in blank cells. The core promoter region of TLR5 included two CpG islands and 16 acting elements. The methylation of the mC-6 site in the second CpG island of the promoter region had a regulatory effect on TLR5 expression. Therefore, TLR5 plays an important regulatory role on E. coli invasion. Low expression of TLR5 inhibited the immune response and decreased cell damage, which was conducive to the resistance to E. coli stimulation. In conclusion, this study preliminarily revealed the molecular mechanism of TLR5 gene regulating the resistance of piglets to Escherichia coli, and provided a new candidate gene for screening Escherichia coli resistance markers in pigs.