VDR/Mcoln-1/TFEB信号通路对创伤性颅脑损伤后自噬流障碍的调控机制研究

Traumatic brain injury (TBI) is a significant public health problem in China. Our previous studies have confirmed that the activation of vitamin D receptor (VDR) could restore neuronal autophagy flux dysfunction induced following TBI, but its underlying mechanism remains to be further explore. Recent studies have shown that Mcoln-1/TFEB pathway is closely related to the fusion of autophagy and lysosome, and might play an essential role in restoring neuronal autophagy flux dysfunction under stress conditions. Moreover, our preliminary experiments showed that the activation of VDR could induce the expression of lysosomal calcium channel protein Mcoln-1 and enhance the number and activity of lysosomes. Thus, we hypothesize that VDR/Mcoln-1/TFEB pathway can promote the fusion of autophagy and lysosomes, thereby restoring neuronal autophagy flux dysfunction after TBI. In order to verify this hypothesis, through in vitro and in vivo studies, we sought to detect related indicators via various experimental methods, such as immunofluorescence and mRFP-GFP-LC3 lentiviral transduction. We further attend to verify the hypothesis through the intervention of important targets. The purpose of this project is to further elucidate the potential mechanism of autophagy in acute brain injury. It also provides new strategies and drug targets for treatment of TBI.

创伤性脑损伤（TBI）是我国严重的公共卫生问题。申请人前期研究证实维生素D受体（VDR）的激活可以修复TBI后的自噬流障碍，但其潜在机制仍亟待进一步探索。最新研究表明Mcoln-1/TFEB通路与自噬-溶酶体的融合密切相关，是应激条件下修复自噬流障碍的关键。预实验发现VDR激活后可以诱导溶酶体钙通道蛋白Mcoln-1的表达，增强溶酶体的数量和活性。由此推测，VDR/Mcoln-1/TFEB信号转导通路能够促进自噬-溶酶体的融合，进而修复TBI后的自噬流障碍。本项目拟通过细胞和动物两个层面的研究，结合免疫荧光、mRFP-GFP-LC3腺病毒转染等多种技术手段，全面考察VDR的激活对Mcoln-1/TFEB通路及自噬流的影响，并通过进一步对重要靶点的干预，确证该信号通路对自噬流障碍的修复作用。本项目旨在进一步阐明自噬在急性神经损伤与保护中的潜在机制，也为TBI的治疗提供新的干预措施和作用靶点。

创伤性脑损伤（TBI）是我国严重的公共卫生问题。流行病学证据显示 TBI 患者神经损伤程度和预后与其体内 VD 水平有关。课题组前期研究证实 维生素D受体（VDR）的激活不仅可以诱导自噬体的形成，还能加快自噬体降解，修复 TBI 后的自噬流障碍，但其潜在机制仍亟待进一步探索。最新研究表明Mcoln-1/TFEB通路与自噬-溶酶体的融合密切相关，是应激条件下修复自噬流障碍的关键。本项目自立项以来，课题组发现 TBI后外源性活性 VD（Calcitriol） 干预能诱导神经元自噬，缓解自噬流障碍，同时可以拮抗 NOX2 过表达导致的氧化应激反应，发挥神经保护作用。接着，我们对VD在 TBI 损伤后对自噬流、氧化应激及细胞凋亡的调控作用进行全面考查，进一步阐明VD的神经活性。在此基础上，本项目从细胞和动物两个层面，阐明VD通过VDR/Mcoln-1/TFEB通路修复TBI后自噬流障碍，清除自由基，对抗氧化应激反应，从而发挥保护作用。这一系列的研究从基础研究角度进一步丰富VD的神经活性，为其在其它中枢神经系统疾病中的作用及相关研究提供理论支持，将有利于进一步阐明自噬在TBI后神经损伤和保护中的潜在机制，为临床治疗TBI提供新策略，亦为研发TBI治疗药物提供新靶点。