摘要
Many G protein-coupled receptors （GPCRs） are reported to be involved in the pathogenesis of multiple sclerosis （MS）, and -40% of all identified GPCRs rely on the Gaq/11 G protein family to stimulate inositol lipid signaling. However, the function of Ga subunits in MS pathogenesis is still unknown. In this study, we attempted to determine the role of Gaq in the pathogenesis of experimental autoimmune encephalomyelitis （EAE）, a well-known mouse model of MS. We discovered that compared with wild-type mice, Gaq-knockout mice exhibited less severe EAE symptoms, with lower clinical scores, reduced leukocyte infiltration and less extensive demyelination. Moreover, a significantly lower percentage of Th17 cells, one of the key players in MS pathogenesis, was observed in Gaq-knockout EAE mice. Studies in vitro demonstrated that deficiency of Gaq in CD4＋ T cells directly impaired Th17 differentiation. In addition, deficiency of Gaq significantly impaired DC-derived IL-6 production, thus inhibiting Th17 differentiation and the Gaq-PLCβ-PKC and Gaq-MAPKs signaling pathways involved in the reduced IL-6 production by DCs. In summary, our data highlighted the critical role of Gaq in regulating Th17 differentiation and MS oathogenesis.
Many G protein-coupled receptors （GPCRs） are reported to be involved in the pathogenesis of multiple sclerosis （MS）, and -40% of all identified GPCRs rely on the Gaq/11 G protein family to stimulate inositol lipid signaling. However, the function of Ga subunits in MS pathogenesis is still unknown. In this study, we attempted to determine the role of Gaq in the pathogenesis of experimental autoimmune encephalomyelitis （EAE）, a well-known mouse model of MS. We discovered that compared with wild-type mice, Gaq-knockout mice exhibited less severe EAE symptoms, with lower clinical scores, reduced leukocyte infiltration and less extensive demyelination. Moreover, a significantly lower percentage of Th17 cells, one of the key players in MS pathogenesis, was observed in Gaq-knockout EAE mice. Studies in vitro demonstrated that deficiency of Gaq in CD4＋ T cells directly impaired Th17 differentiation. In addition, deficiency of Gaq significantly impaired DC-derived IL-6 production, thus inhibiting Th17 differentiation and the Gaq-PLCβ-PKC and Gaq-MAPKs signaling pathways involved in the reduced IL-6 production by DCs. In summary, our data highlighted the critical role of Gaq in regulating Th17 differentiation and MS oathogenesis.
基金
This work was supported by grants from the Ministry of Science and Technology of China （2014CB541903, 2012CB910404）, the National Natural Science Foundation of China （31171348, 31371414）, the Shanghai Municipal Education Commission （14zz042）, the State Key Laboratory of Drug Research （SIMM1302KF-09） and the Fundamental Research Funds for the Central Universities.
