FcRn在奶山羊乳腺IgG转运中的作用及其调控机理研究

牛羊乳来源的IgG不仅能为初生反刍动物提供被动免疫，还可为人类提供免疫保护。提高乳中IgG含量，研究开发富含IgG的功能乳品是我国现代奶业发展的新方向。FcRn作为IgG的转运工具，是决定奶中IgG含量的关键因素。但目前FcRn在反刍动物乳腺IgG转运中的作用、特征及其调控机理尚不清楚。因此，本项目围绕奶山羊乳腺FcRn开展以下研究：1）从FcRn在乳腺表达定位及其与血/乳中IgG含量相关性入手，结合IgG转运方向和转运效率研究，阐明FcRn在山羊乳腺IgG转运中的作用；2）从激素应答性、酸碱度偏好特性和饱和动力学特性等方面，解析调控FcRn表达和IgG转运的主要因素；3）以GR调控通路为深入点，探明GR直接或通过NF-κB信号通路参与FCGRT基因表达和IgG转运过程中的分子机理。本项目的实施和研究成果，不仅为提高乳中IgG含量提供科学依据，还为我国奶业的升级转型奠定实践基础。

The immunoglobulin G (IgG) from milk of dairy cattle and goat provides passive immunity and protection for newborn ruminants and humans. Increase the concentration of IgG in the milk plays important role in the development of modern dairy industry in China. Neonatal Fc receptor (FcRn) plays key role in transportation of IgG from blood stream to milk. Therefore, in this study, we investigate the effects and regulatory mechanism of FcRn on IgG transport in mammary gland of dairy goats. Firstly, the function of FcRn was identified based on the expression/location of FcRn in the mammary gland and its relationship with IgG content in milk and serum, and the direction and efficiency of IgG transportation was also investigated. Secondly, the regulatory patterns and the major factors affecting FcRn expression and IgG transportation were investigated using lactogenic hormones, acid-based treatment, and substrates treatment. Thirdly, the possible mechanism of glucocorticoids receptor (GR) regulating FcRn expression directly or by affecting NF-κB signaling pathway was investigated. The results of this study will provide scientific basis for regulating the IgG concentration in milk, and facilitate the development of dairy industry in China.