Kupffer细胞中Galectin-1调控Th免疫平衡偏移诱导大鼠肝移植免疫耐受形成

Kupffer cells（KCs），the special resident macrophages of the liver，and the induced tolerance of the liver are well accepted. Therefore，much attenion has focusd on the possible roles and mechanism of KCs from liver allograft in tolerance induction，although the researches has been continued for decades，the full picture is still foggy. Our group found that KCs is a "double-edged"sword during the proceeding of acute rejection（AcR），and its mechanism is closely associated with modulated Th1/Th2 and/or Th17/Treg homeostasis. previous NSFC project found that Tim-3/Galectin-9 could indirectly shewing Th1/Th2 and Th17/Treg paradigms via apoptosis Th1 and Th17 cells then postpone the preocess of acute rejection post-transplant.However，Galectin-1（Gal-1）,the same family member as Galectin-9's,could moudulate the all four actived CD4+ Th cell through its glycan binding property directly. We hypothesized that Gal-1 possess much more immune modulating potency compared with Tim-3/Gal-9 pathway,but there is only a few reports in solid organ transplantation， especially in liver. We hereby purpose a hypothesis that overexpress Gal-1 in KCs may induce liver transplant tolerance via cytokine related Th paradigms deviation and actived apoptosis of effector Th cell. To investgate the possible role of Ga-1 in the induction of posttransplant tolerance，we using Ad-Gal-1 and Gal-1-shRNAs plasmid to regulate the expression of Gal-1 in vitro and in vivo. once our hypothesis is corroborated，this may provide a novel target for study the AcR process.

移植肝脏具有诱导免疫耐受的重要原因是肝内存在Kupffer细胞（KCs）等特异性免疫细胞。项目组前期研究发现：(1)KCs在移植肝脏中既有促急性排斥反应又有诱导免疫耐受的双重作用，其原因与Th1/Th2及Th17/Treg免疫平衡有关；（2）Tim-3/Galectin（Gal）-9通路可通过诱导Th1/Th17细胞凋亡、间接诱导免疫平衡偏移。但这一通路对Th2/Treg细胞无任何调节作用，上调Gal-9表达仅能一定程度延缓急性排斥反应发生，不能诱导免疫耐受形成。据报道Gal-1直接参与调控Th细胞四种亚型平衡，较Gal-9可能具有更强的诱导免疫偏移能力。因此，探讨Gal-1在移植肝脏免疫耐受的形成机制具有重要意义。本项目选择KCs为靶细胞，以Gal-1为切入点，通过调控Gal-1在体内外的表达，探讨Kupffer细胞中Gal-1调控Th免疫平衡偏移、诱导大鼠肝移植免疫耐受中的确切机制。

Kupffer细胞（KCs）在术后诱导移植肝脏免疫耐受中起着双重效应，其原因与Th1/Th2与Th17/Treg有关，但其确切机制目前尚不清楚。本课题通过抑制或过表达KCs中Galectin-1活性，探讨Galectin-1诱导Th免疫偏移与诱导肝移植术后免疫耐受的分子机制。研究发现：(1)增强KCs中Galectin-1表达可以促进GATA-3、FoxP3表达，减少T-bet、RORγt的分泌，有利于Th1/Th17向Th2/Treg免疫偏移并抑制T淋巴细胞增殖及凋亡水平。降低KCs 中Galectin-1表达则使Th2/Treg向Th1/Th17偏移，同时调节促炎因子与抑炎因子的分泌从而影响KCs功能。(2) 通过转染携带过表达和抑制Galectin-1的明胶纳米粒，上调断受体肝脏KCs中Galectin-1表达，可以改善急性排斥模型受体的生存时间以及肝脏功能，并能减轻AcR对肝脏组织的破坏程度，而下调Galectin-1的表达会加重耐受模型的排斥反应，增强对对肝脏组织的破坏；以上结果提示：Galectin-1能够调控Th细胞增殖凋亡及其亚型分化倾向的生物学效应，诱导Th1/Th17向 Th2/Treg 免疫偏倚，有利于免疫耐受微环境的诱导。