Li Ming, Wang Zhenglei, Fu Shaodong, Sun Naiyan, Li Weizhen, Xu Yuanyuan, Han Xiangan, Zhang Jinqiu, Miao Jinfeng
MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; College of Veterinary Medicine, Yunnan Agricultural University, Kunming 650201, China.
MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Int Immunopharmacol. 2023 Nov;124(Pt B):111028. doi: 10.1016/j.intimp.2023.111028. Epub 2023 Oct 17.
Mastitis is a common disease of dairy cows characterized by infiltration of leukocytes, especially neutrophils, resulting in increased permeability of the blood-milk barrier (BMB). Taurine, a functional nutrient, has been shown to have anti-inflammatory and antioxidant effects. Here, we investigated the regulatory effects and mechanisms of taurine on the complex immune network of the mammary gland in Streptococcus uberis (S. uberis) infection. We found that taurine had no direct effect on CXCL2-mediated neutrophil chemotaxis. However, it inhibited MAPK and NF-κB signalings by modulating the activity of TAK1 downstream of TLR2, thereby reducing CXCL2 expression in macrophages to reduce neutrophil recruitment in S. uberis infection. Further, the AMPK/Nrf2 signaling pathway was activated by taurine to help mitigate oxidative damage, apoptosis and disruption of tight junctions in mammary epithelial cells caused by hypochlorous acid, a strong oxidant produced by neutrophils, thus protecting the integrity of the mammary epithelial barrier. Taurine protects the BMB from damage caused by neutrophils via blocking the macrophage-CXCL2-neutrophil signaling axis and increasing the antioxidant capacity of mammary epithelial cells.
乳腺炎是奶牛的一种常见疾病，其特征是白细胞尤其是中性粒细胞浸润，导致血乳屏障（BMB）通透性增加。牛磺酸作为一种功能性营养素，已被证明具有抗炎和抗氧化作用。在此，我们研究了牛磺酸对乳房链球菌（乳房链球菌）感染中乳腺复杂免疫网络的调节作用及其机制。我们发现牛磺酸对CXCL2介导的中性粒细胞趋化性没有直接影响。然而，它通过调节TLR2下游TAK1的活性来抑制MAPK和NF-κB信号通路，从而降低巨噬细胞中CXCL2的表达，以减少乳房链球菌感染中的中性粒细胞募集。此外，牛磺酸激活了AMPK/Nrf2信号通路，以帮助减轻由中性粒细胞产生的强氧化剂次氯酸引起的乳腺上皮细胞氧化损伤、凋亡和紧密连接破坏，从而保护乳腺上皮屏障的完整性。牛磺酸通过阻断巨噬细胞-CXCL2-中性粒细胞信号轴并提高乳腺上皮细胞的抗氧化能力，保护血乳屏障免受中性粒细胞造成的损伤。
