雷帕霉素与他克莫司调控CD4+T细胞亚群GAL-9/CEACAM1/TIM-3/BAT3信号通路在参与肾移植受者慢性移植物失功中的机制研究

This study focuses on the regulatory effect of different immunosuppressants on Th1/Th2, Th17/Treg cell activation and tolerance via GAL-9/CEACAM1/TIM-3/BAT3 signaling pathway of CD4+T cell. Based on the results of our previous studies on regulatory effect of immunosuppressants on T cell subsets imbalance and negative molecules in transplant recipients as well as our pilot study, we speculate that the increased expression of BAT3 in renal transplant recipients with tacrolimus would inhibit the activity of negative molecules GAL-9/CEACAM1/TIM-3 pathway and induce the imbalance of Th1/Th2，Th17/Treg, including increased activity of Th1 and Th17 as well as inhibition of Treg, which would result in the chronic inflammation status of the recipients and contribute to chronic allograft dysfunction; Meanwhile, sirolimus could increase the expression of negative molecules GAL-9/CEACAM1/TIM-3 pathway and induce the detachment of BAT3, which would cause the inhibition of Th1, Th17 and stimulation of Treg so that the imbalance of CD4+T cell subsets of recipients with chronic allograft dysfunction could be reversed effectively. By figuring out such regulatory mechanism, we hope to prove that regulating GAL-9/CEACAM1/TIM-3/BAT3 signaling pathway by immunosuppressants is an important therapeutic target of renal transplant recipients with chronic allograft dysfunction.

本研究拟关注不同免疫抑制剂对肾移植受者CD4+T细胞GAL-9/CEACAM1/TIM-3/BAT3信号通路对Th1/Th2、Th17/Treg细胞活化和耐受的调节作用。基于免疫抑制剂对移植患者T细胞亚群平衡偏移及负性分子调控作用的前期研究及预实验结果，推测使用他克莫司的肾移植受者高表达的BAT3分子抑制了负性分子GAL-9/CEACAM1/TIM-3通路活性，致Th1/Th2，Th17/Treg平衡偏移，Th1及Th17活跃，Treg受抑，受者处于慢性炎症状态，是导致慢性移植物失功的重要因素；雷帕霉素可调节负性分子GAL-9/CEACAM1/TIM-3通路高表达，使BAT3分子解离，Th1及Th17功能受抑，Treg功能活跃，可有效逆转慢性移植物失功受者CD4+T细胞亚群平衡偏移，拟证实药物调控GAL-9/CEACAM1/TIM-3/BAT3信号通路是治疗肾移植慢性移植物失功的重要靶点。

分析不同免疫抑制药物的作用靶点，研究导致长期移植受者移植物慢性失功的关键原因，仍是目前国内外学者高度关注并希望解决的焦点。本研究通过他克莫司和雷帕霉素对肾移植受者体内CD4+T细胞上TIM-3、GAL-9、CEACAM-1表达影响，血清sTIM-3、sGAL-9、sCEACAM-1表达影响的横断面和队列研究，首次从临床角度证实了雷帕霉素通过上调sCEACAM-1表达，促进了GAL-9介导的免疫抑制信号通路，有助于肾移植受者免疫耐受状态的维持和长期移植物功能的维持。血清sTIM-3, sGAL-9高表达，可竞争性抑制细胞表面TIM-3/GAL-9信号通路，促进CD4+T细胞及其亚类免疫活化和炎性反应发生，负性调节TIM-3/GAL-9信号通路异常, 趋化因子CXCL9、CXCL13等介导炎性反应细胞向移植肾组织趋化，最终导致了移植物排斥反应发生。基于上述研究结果，本研究进一步利用实验室和临床数据，成功建立并验证了两个基于肾移植受者术后早期的常规实验室指标和临床资料的术后5年移植肾失功预测模型，该模型的建立有助于在早期提示肾移植受者术后5年内发生失功的风险，据此可提醒肾移植受者和临床医生调整医院随访方案和免疫抑制剂用药方案，从而阻止或延缓移植肾失功的发生。本研究通过胰岛移植动物模型，证实了cross-dressing在介导肾移植术后排斥反应中的重要作用，P2X7R抑制剂可有效抑制cross-dressing介导的排斥反应发生。. 血清sTIM-3、sGAL-9可作为预测肾移植术后不良结局的早期免疫学标志物，sCEACAM-1可作为雷帕霉素免疫效应学的免疫评价指标，针对相关信号通路的靶向药物，或可预防和延缓肾移植术后移植肾失功的发生。