School of Medicine, Chongqing University, Chongqing, P.R. China.
Department of Pathology, Chongqing University Cancer Hospital, Chongqing, P.R. China.
J Alzheimers Dis. 2024;100(1):279-296. doi: 10.3233/JAD-231300.
Mitochondrial dysfunction exists in Alzheimer's disease (AD) brain, and damaged mitochondria need to be removed by mitophagy. Small GTPase Rab7 regulates the fusion of mitochondria and lysosome, while TBC1D5 inhibits Rab7 activation. However, it is not clear whether the regulation of Rab7 activity by TBC1D5 can improve mitophagy and inhibit AD progression.
To investigate the role of TBC1D5 in mitophagy and its regulatory mechanism for Rab7, and whether activation of mitophagy can inhibit the progression of AD.
Mitophagy was determined by western blot and immunofluorescence. The morphology and quantity of mitochondria were tracked by TEM. pCMV-Mito-AT1.03 was employed to detect the cellular ATP. Amyloid-β secreted by AD cells was detected by ELISA. Co-immunoprecipitation was used to investigate the binding partner of the target protein. Golgi-cox staining was applied to observe neuronal morphology of mice. The Morris water maze test and Y-maze were performed to assess spatial learning and memory, and the open field test was measured to evaluate motor function and anxiety-like phenotype of experimental animals.
Mitochondrial morphology was impaired in AD models, and TBC1D5 was highly expressed. Knocking down TBC1D5 increased the expression of active Rab7, promoted the fusion of lysosome and autophagosome, thus improving mitophagy, and improved the morphology of hippocampal neurons and the impaired behavior in AD mice.
Knocking down TBC1D5 increased Rab7 activity and promoted the fusion of autophagosome and lysosome. Our study provided insights into the mechanisms that bring new possibilities for AD therapy targeting mitophagy.
阿尔茨海默病（AD）大脑存在线粒体功能障碍，受损的线粒体需要通过自噬体清除。小 GTP 酶 Rab7 调节线粒体和溶酶体的融合，而 TBC1D5 抑制 Rab7 的激活。然而，TBC1D5 对 Rab7 活性的调节是否能改善自噬体并抑制 AD 的进展尚不清楚。
研究 TBC1D5 在自噬体中的作用及其对 Rab7 的调节机制，以及激活自噬体是否能抑制 AD 的进展。
通过 Western blot 和免疫荧光法检测自噬体。通过 TEM 跟踪线粒体的形态和数量。使用 pCMV-Mito-AT1.03 检测细胞内的 ATP。通过 ELISA 检测 AD 细胞分泌的淀粉样β。通过共免疫沉淀法研究靶蛋白的结合伴侣。高尔基 cox 染色用于观察小鼠神经元的形态。通过 Morris 水迷宫测试和 Y 迷宫评估空间学习和记忆，通过旷场测试测量实验动物的运动功能和焦虑样表型。
AD 模型中线粒体形态受损，TBC1D5 表达水平升高。敲低 TBC1D5 增加了活性 Rab7 的表达，促进了溶酶体和自噬体的融合，从而改善了自噬体，并改善了 AD 小鼠海马神经元的形态和受损的行为。
敲低 TBC1D5 增加了 Rab7 活性，促进了自噬体和溶酶体的融合。我们的研究为靶向自噬体治疗 AD 的机制提供了新的见解，为 AD 治疗带来了新的可能性。
