Deng Shoulong, Yu Kun, Jiang Wuqi, Li Yan, Wang Shuotian, Deng Zhuo, Yao Yuchang, Zhang Baolu, Liu Guoshi, Liu Yixun, Lian Zhengxing
State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China.
Laboratory of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 People's Republic of China.
J Anim Sci Biotechnol. 2017 Jan 9;8:3. doi: 10.1186/s40104-016-0136-2. eCollection 2017.
Mastitis, an infection caused by Gram-positive bacteria, produces udder inflammation and oxidative injury in milk-producing mammals. Toll-like receptor 2 (TLR2) is important for host recognition of invading Gram-positive microbes. Over-expression of in transgenic dairy goats is a useful model for studying various aspects of infection with Gram-positive bacteria, in vivo.
We over-expressed in transgenic dairy goats. Pam3CSK4, a component of Gram-positive bacteria, triggered the TLR2 signal pathway by stimulating the monocytes-macrophages from the -positive transgenic goats, and induced over-expression of activator protein-1 (AP-1) phosphatidylinositol 3-kinase (PI3K) and transcription factor nuclear factor kappa B (NF-κB) and inflammation factors downstream of the signal pathway.
Compared with wild-type controls, measurements of various oxidative stress-related molecules showed that , when over-expressed in transgenic goat monocytes-macrophages, resulted in weak lipid damage, high level expression of anti-oxidative stress proteins, and significantly increased mRNA levels of transcription factor NF-E2-related factor-2 (Nrf2) and the downstream gene, heme oxygenase-1 (HO-1). When Pam3CSK4 was used to stimulate ear tissue in vivo the HO-1 protein of the transgenic goats had a relatively high expression level.
The results indicate that the oxidative injury in goats over-expressing was reduced following Pam3CSK4 stimulation. The underlying mechanism for this reduction was increased expression of the anti-oxidation gene by activation of the Nrf2 signal pathway.
乳腺炎是由革兰氏阳性菌引起的感染，可导致产奶哺乳动物的乳房炎症和氧化损伤。Toll样受体2（TLR2）对于宿主识别入侵的革兰氏阳性微生物很重要。在转基因奶山羊中过表达TLR2是研究革兰氏阳性菌感染各个方面的有用体内模型。
我们在转基因奶山羊中过表达了TLR2。革兰氏阳性菌的成分Pam3CSK4通过刺激来自TLR2阳性转基因山羊的单核细胞-巨噬细胞来触发TLR2信号通路，并诱导信号通路下游的激活蛋白-1（AP-1）、磷脂酰肌醇3激酶（PI3K）、转录因子核因子κB（NF-κB）和炎症因子的过表达。
与野生型对照相比，各种氧化应激相关分子的测量结果表明，当在转基因山羊单核细胞-巨噬细胞中过表达时，TLR2导致脂质损伤较弱、抗氧化应激蛋白的高水平表达，以及转录因子NF-E2相关因子2（Nrf2）及其下游基因血红素加氧酶-1（HO-1）的mRNA水平显著增加。当使用Pam3CSK4在体内刺激耳部组织时，转基因山羊的HO-1蛋白具有相对较高的表达水平。
结果表明，Pam3CSK4刺激后，过表达TLR2的山羊的氧化损伤减少。这种减少的潜在机制是通过激活Nrf2信号通路增加抗氧化基因HO-1的表达。
