氧化应激下TRPM2介导白癜风黑素细胞免疫损伤的机制研究

Oxidative stress promotes the secretion of chemokines from keratinocytes, which leads to the skin skin trafficking of CD8+T cells and subsequent melanocyte destruction in vitiligo. However, the upstream regulatory mechanism of chemokine secretion induced by oxidative stress is still unclear. Recently, it is reported that TRPM2-mediated calcium overload inhibits mitophagy, and the inhibition of mitophagy can cause chemokine secretion. In our previous studies, we found that oxidative stress increased the expression of TRPM2 in keratinocytes, which was necessary for the production of CXCL10 and CXCL16 as well as the inactivation of mitophagy. Based on these findings, we hypothesize that TRPM2-mediated calcium overload inhibits mitophagy and then promotes the secretion of CXCL10 and CXCL16, which contributes to immune-mediated destruction of melanocytes and the formation of vitiligo. We will first confirm the activation of TRPM2 in vitiligo lesions and keratinocyte models under oxidative stress, and then screen out the differently expressed molecules in the models and ultimately clarify the mechanism of TRPM2-mediated mitophagy inhibition and chemokines production through a series of functional experiments. The project will help to elucidate the mechanism of immune-mediated destruction of melanocytes under oxidative stress and provide new therapeutic targets for the treatment of vitiligo.

氧化应激下角质形成细胞释放趋化因子，诱导CD8+T细胞向表皮迁移是导致白癜风黑素细胞免疫损伤的关键环节，但其上游调控机制尚不清楚。最新研究表明，氧化应激下，TRPM2可介导钙超载抑制线粒体自噬，而线粒体自噬抑制可促进趋化因子分泌。我们发现，氧化应激下角质形成细胞TRPM2表达升高，且调控趋化因子CXCL10、CXCL16分泌，并参与氧化应激诱导的线粒体自噬抑制，由此提出科学假说：氧化应激下角质形成细胞TRPM2介导钙超载抑制线粒体自噬，促进CXCL10、CXCL16分泌，进一步诱导CD8+T细胞皮肤迁移，从而导致黑素细胞免疫损伤。本项目拟首先在临床样本及角质形成细胞氧化应激模型中验证现象，进一步通过筛选差异表达分子并结合功能实验，阐明TRPM2调控线粒体自噬及趋化因子分泌的作用及机制，预期结果将揭示氧化应激诱导白癜风黑素细胞免疫损伤的重要调控机制，为白癜风治疗策略提供理论依据和关键靶点。

氧化应激下角质形成细胞释放趋化因子是诱导CD8+T细胞向表皮迁移活化，导致黑素细胞损伤的关键因素，但其上游调控机制尚不清楚。自噬是细胞的保护机制，本项目旨在研究自噬在氧化应激诱导的角质形成细胞趋化因子分泌中的作用和机制。我们首先在临床样本中明确白癜风角质形成细胞存在自噬障碍，随后利用体外细胞实验证实氧化应激下角质形成细胞自噬水平障碍促进趋化因子CXCL10、CXCL16分泌，进一步对氧化应激诱导自噬障碍以及自噬障碍促进趋化因子分泌的机制进行探讨，发现氧化应激通过TRPM2介导的Ca2+内流，激活角质形成细胞Calpian1，促进Atg5剪切，抑制Atg5-Atg12复合体形成，从而抑制自噬。重要的是，Atg5表达降低通过激活TBK1及下游转录因子IRF3，促进CXCL10、CXCL16分泌。本项目首次揭示了自噬障碍在氧化应激诱导角质形成细胞趋化因子分泌中的作用，并阐明了氧化应激通过TRPM2介导的Ca2+内流抑制自噬，促进趋化因子CXCL10、CXCL16分泌的机制。研究结果丰富了白癜风发病机制研究，并为白癜风治疗策略提供了潜在靶点。