TREM-1介导真菌性角膜炎免疫学发病机制及信号调控研究

Fungal infections of the cornea are an important cause of blindness and visual impairment worldwide. Excessive and unregulated inflammation after fungal infection can lead to tissue damage and corneal perforation. The Triggering Receptor Expressed on Myeloid cells 1 (TREM-1) is a cell surface receptor of the immunoglobulin superfamily, which is involved in immune response to bacterial and fungal infections, particularly by amplifying the production of pro-inflammatory cytokines by the host. The precise mechanism of TREM-1 is still remaining unclear, let alone its function in fungal keratitis. The present research using a fungal keratitis murine model has provided substantial information about the ocular immune response to fungal infection. Our study provide evidence that TREM-1 not only synergizes with TLRs in the inflammatory response to fungal infection, but also interact with other PRRs such as dectin-1. Our further investigation will focuse on the TREM-1 pathway and the interaction between TREM-1 pathway and other inflammation relating pathways, which help better understand the mechanisms by which TREM-1 activation occurs. Furthermore our findings also show FK506 has a suppress effect in both the expression of TREM-1 and in the secretion of inflammatory cytokines such as IL-1β and TNFα induced by zymosan, which indicate that FK506 can possibly be a new medication for fungal keratitis.

真菌性角膜炎是常见的致盲性眼病，过度炎症反应是造成角膜损伤的病理基础，近年研究证实TREM-1是放大炎症反应的重要启动因子。我们的前期研究证实病变角膜中TREM-1表达水平与角膜损害程度具有高度相关性，但其介导免疫炎症反应的发病机制和调控环节尚不明确。本研究建立真菌性角膜炎动物模型，在TREM-1参与及缺失背景下，观察免疫效应细胞，趋化和迁移的的时空规律，分析TREM-1与TLRs及Dectin-1表达水平的变化趋势及关联性，检测下游炎性细胞因子表达谱的改变规律，阐明TREM-1介导真菌性角膜炎免疫学发病机制。通过蛋白质芯片技术筛选TREM-1信号通路，分析差异蛋白的作用，明确TREM-1的信号传递通路和调控环节。评价免疫抑制剂FK506对TREM-1信号通路的拮抗作用及起效机制，建立分别针对TREM-1受体和信号通路的二级联动免疫治疗新模式。

真菌性角膜炎是常见的致盲性眼病，过度炎症反应是造成角膜损伤的病理基础，近年研究证实TREM-1是放大炎症反应的重要启动因子。本项目研究了TREM-1参与及缺失背景下，免疫效应细胞，趋化和迁移的的时空规律，分析TREM-1与Dectin-1表达水平的变化趋势及关联性，及二者共同调控病程发展的机制，检测下游炎性细胞因子表达谱的改变规。此外评价了免疫抑制剂FK506对TREM-1信号通路的拮抗作用及起效机制，并评价伏立康唑纳米银复合膜治疗烟曲霉菌性角膜炎的疗效分析。.实验结果表明，1.TREM-1在真菌性角膜炎病变角膜中高表达，与真菌性角膜炎的发病密切相关。 2.TREM-1可放大真菌性角膜炎中的炎症反应，阻断TREM-1的激活能减轻真菌性角膜炎的病情。3. 真菌性角膜炎病变角膜中TREM-1/Dectin-1随病程延长呈现上升趋势，发病早期TREM-1的表达是正常角膜的12倍，晚期则上升为40倍；Dectin-1相同时间段的病变角膜内表达是正常角膜的8倍，晚期为30倍。真菌性角膜炎动物模型中TREM-1/Dectin-1的mRNA变化规律与病变严重程度有相关性。4. 靶向拮抗TREM-1/Dectin-1在角膜的表达，可通过调节Th1型/Th2型炎性因子的表达平衡，从而抑制其介导的过度炎症反应；同时也通过增强NO 和iNOS的对真菌的清除，从而改善真菌性角膜炎的预后，为真菌性角膜炎的免疫干预治疗提供了实验依据和理论基础。5.FK506可抑制真菌性角膜炎中TREM-1的激活，从而通过减轻炎症反应治疗真菌性角膜炎。6. 伏立康唑纳米银生物膜材料性质稳定，局部贴附未见眼表明显病理损害及炎症反应，具有良好的生物相容性；伏立康唑纳米银生物膜通过伏立康唑缓释给药破坏真菌结构，联合纳米银抑制真菌的作用，可获得显著的真菌清除效能，改善真菌性角膜炎的预后。.上述研究结果已经在ACS Nano(IF13),plos one，中华实验眼科杂志等期刊发表论著4篇，本研究成功丰富了真菌性角膜炎免疫学发病机制理论，建立了新的抗炎抗感染治疗策略，并发展了全新的抗真菌感染治疗模式。