磷酸酶SHP2促进IL-23转录加剧银屑病发病的分子机制及潜在药靶研究

Psoriasis is a chronic skin autoimmune disease, and the detailed pathomechanism remains unclear. Our previous studies showed that phosphatase SHP2 aggravated psoriasis in mice through promoting the transcription of IL-23. This project is to investigate the critical role of SHP2 in the pathogenesis of psoriasis. To explore the dynamic relationship between SHP2 activation and skin inflammation, macrophages, dendritic cells and T cells from mice at different stages of imiquimod-induced psoriasis were separated and analyzed; Using macrophage, dendritic cell or T cell SHP2 conditional knockout mice, the effect and mechanism of SHP2 deficiency on imiquimod-induced murine psoriasis model was investigated; To explore the detailed mechanism of SHP2's up-regulating IL-23 transcription in imiquimod-induced murine psoriasis model, the new partners of SHP2 were identified using phosphoproteomics and Co-IP-MS; Using psoriasis patients' blood and skin pathological samples, the correlation between SHP2 and its downstream related signaling pathways and the occurrence and development of psoriasis was further clarified. Using various SHP2 small molecule inhibitors, the effect of SHP2 inhibition on imiquimod-induced murine psoriasis model was examined. The successful implementation of this project will provide an experimental basis for elucidating the pathological mechanism of psoriasis and the discovery of new potential drug targets.

银屑病是一种累及皮肤的慢性自身免疫性疾病，详细发病机制仍不清楚。前期研究发现，磷酸酶SHP2可促进银屑病发病过程中关键性细胞因子IL-23的转录，加剧小鼠银屑病发病。本项目拟进一步解析不同发病时期小鼠皮损组织巨噬细胞、树突状细胞及T细胞中SHP2的变化特征，探讨SHP2活化与皮肤炎性因子动态改变的内在关联；分别运用巨噬细胞、树突状细胞以及T细胞上SHP2条件性敲除鼠，考察不同细胞上敲除是否改善小鼠银屑病发病；进一步阐明SHP2调控IL-23转录的详细机制，结合磷酸化蛋白质组学手段寻找SHP2直接或间接影响的转录因子，挖掘SHP2新的调控模式；借助临床银屑病患者血液和皮损样本，明确SHP2与银屑病发生发展的相关性；利用SHP2小分子抑制剂进一步确证体内改善小鼠银屑病的疗效，为SHP2作为银屑病新型药物治疗靶标奠定基础。本项目的成功实施将为阐明银屑病的病理机制以及发现新的潜在药靶提供实验依据。

银屑病是一种由遗传、免疫及感染等多种因素诱发的慢性自身免疫性皮肤病，病程长、易复发，亟需发现新的疾病干预靶标。该项目通过临床样本单细胞测序结合实验验证，发现SHP2在银屑病患者皮损组织中的巨噬细胞上高表达，且酶活上调，使用SHP2抑制剂或巨噬细胞上条件性敲除SHP2均可显著改善小鼠银屑病样皮肤炎症。生理状态下，巨噬细胞中TLR7发生酪氨酸磷酸化，招募SHP2并脱去TLR7第1024位点的磷酸化，进而发生K63泛素化修饰，经非经典内吞体分选转运复合体（ESCRT）途径分拣，招募适配蛋白AP-4并被转运至内体，引起下游NF-κB通路的活化。这一SHP2介导的TLR7内体转运稳态机制在银屑病中被打破，因SHP2高表达显著增加TLR7在内体的定位，致内体转运稳态失衡，引起NF-κB通路过度活化，巨噬细胞分泌大量炎性因子，加剧了银屑病进展。TLR7去磷酸化修饰位点的点突变knock-in小鼠（模拟SHP2抑制剂效果）银屑病样症状显著减轻也进一步佐证了“SHP2-TLR7-内体转运稳态轴”在银屑病发病中的重要作用。该研究首次报道了巨噬细胞中TLR7的去磷酸化修饰可调控内体转运的稳态，阐明了SHP2通过脱TLR7磷酸化促进其内体转运加剧银屑病进展的分子机制，为银屑病的治疗提供了新干预靶标。鉴于该成果对于银屑病治疗领域的重要意义，中国青年网“百秒观科研”栏目进行了报道。申请人受邀2021国际药理学前沿交叉论坛做题为Targeting SHP2 as a promising strategy for inflammation-related diseases的大会报告。该项目共发表标注81872877资助的SCI论文15篇（其中影响因子大于10的11篇，封面文章3篇，高被引1篇）。该项目执行期间，共培养博士生11名，其中已毕业6名；培养硕士生15名，其中已毕业9名。参加国际学术会议4次，国内学术会议8次。申请国家发明专利5项，获授权2项。以第三完成人获2018年度教育部自然科学一等奖1项。