College of Animal Science and Technology, Northeast Agricultural University, Harbin, PR China; Key Laboratory of Animal Genetics, Breeding and Reproduction, Education Department of Heilongjiang Province, Harbin, PR China.
Beijing Key Laboratory of Animal Genetic Improvement, China Agricultural University, Beijing, PR China.
Theriogenology. 2017 Jul 1;96:103-110. doi: 10.1016/j.theriogenology.2017.04.006. Epub 2017 Apr 5.
Genetic modification provides a means to enhancing disease resistance in animals. Toll-like receptor 4 (TLR4), a member of the TLR family, is critical for the recognition of lipopolysaccharide (LPS)/endotoxin from Gram-negative bacteria by host immune cells, which initiates cell activation and subsequently triggers a proinflammatory response to the invading pathogens. In this study, the first generation of genetically modified (GM) sheep overexpressing TLR4 was produced by microinjection for better disease resistance. Compared with wild-type (WT) rams, the GM rams have similar growth performance, basic semen quality and spermatozoon ultrastructure. The offspring birth rates after cervical artificial insemination were also similar between GM (90.32%) and WT (92.38%) rams. Overall, the presence and expression of the TLR4 transgene in the genome did not appear to interfere with normal semen production, reproductive traits and the ability of transgene transmission to offspring. The expression levels of TLR4, tumor necrosis factor and interferon gamma genes in monocyte/macrophages from GM sheep were significantly higher than that from WT sheep at early stages after LPS stimulation. The GM offspring born from the founder transgenic ram inseminated ewes had similar survival rate with WT offspring (88.89% vs 84.86%) at weaning. The TLR4 transgene showed no deleterious effects on growth performance, reproductive traits and offspring survivability of GM rams. Therefore, the GM sheep overexpressing TLR4 provide a powerful experimental model for analyzing function of TLR4 in vivo during infection and inflammation.
遗传修饰为增强动物的抗病能力提供了一种手段。Toll 样受体 4（TLR4）是 TLR 家族的成员，对于宿主免疫细胞识别革兰氏阴性细菌的脂多糖（LPS）/内毒素至关重要，它启动细胞激活，随后引发对入侵病原体的促炎反应。在这项研究中，通过显微注射产生了第一代过表达 TLR4 的转基因（GM）绵羊，以提高抗病能力。与野生型（WT）公羊相比，GM 公羊具有相似的生长性能、基本精液质量和精子超微结构。GM（90.32%）和 WT（92.38%）公羊经颈人工授精后的后代出生率也相似。总体而言，TLR4 转基因在基因组中的存在和表达似乎并未干扰正常的精液产生、繁殖性状和转基因向后代的传递能力。在 LPS 刺激后早期，GM 绵羊单核细胞/巨噬细胞中 TLR4、肿瘤坏死因子和干扰素 γ 基因的表达水平明显高于 WT 绵羊。从转基因公羊授精母羊出生的 GM 后代在断奶时与 WT 后代的存活率相似（88.89%比 84.86%）。TLR4 转基因对 GM 公羊的生长性能、繁殖性状和后代存活率没有不良影响。因此，过表达 TLR4 的 GM 绵羊为分析 TLR4 在感染和炎症期间体内功能提供了一个强大的实验模型。
