ABSTRACT

Macroautophagy/autophagy (hereafter autophagy), the process of mass degradation of unnecessary elements within the cell, is often dysregulated in many diseases such as cancer, atherosclerosis, and neurodegenerative diseases. Hence, autophagy modulating agents have a great potential to be therapeutic agents for the autophagy-related diseases. Here we report that an anti-depressant drug sertraline (Sert) is an autophagy-inducing agent. Mechanistically, Sert potentially binds to and antagonizes the mitochondrial VDAC1 (voltage dependent anion channel 1), resulting in reduced cellular ATP (adenosine triphosphate) level, activation of AMP-activated protein kinase (AMPK) and inhibition of its downstream, MTOR (mechanistic target of rapamycin kinase)-RPS6KB1 (ribosomal protein S6 kinase B1) signaling pathway. Cells lacking VDAC1 expression completely abrogate the modulatory effect of Sert on AMPK-MTOR pathway and autophagy-inducing activity. We further show that Sert suppresses tauopathy by promoting the autophagic degradation of MAPT (microtubule associated protein tau) protein via inducing autophagy. Our study demonstrates the potential of Sert as a novel small molecule autophagy-inducing agent and provides a new drug candidate to treat autophagy related diseases by targeting VDAC1.

Abbreviations: AMP: adenosine monophosphate; AMPK: AMP-activated protein kinase; ATP: adenosine triphosphate; Baf: bafilomycin A₁; BiFC: biomolecular fluorescence complementation; CAMKK2/CAMKKB: calcium/calmodulin dependent protein kinase kinase 2; CC: compound C; DARTS: drug affinity responsive target stability; HUVECs: human umbilical vein endothelial cells; Inda: indatraline; STK11/LKB1: serine/threonine kinase 11; MAPT: microtubule associated protein tau; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; 3-MA: 3-methyladenine; MEFs: mouse embryonic fibroblasts; MTOR: mechanistic target of rapamycin kinase; PI3K: phosphoinositide 3-kinase; Rapa: rapamycin; Sert: sertraline; RPS6KB1: ribosomal protein S6 kinase B1; SQSTM1/p62: sequestosome 1; SLC6A4/SERT1: solute carrier family 6 member 4; TFEB: transcription factor EB; VDAC1: voltage dependent anion channel 1; WT: wild-type; WM: wortmannin.

摘要

巨自噬/自噬（以下简称自噬）是细胞内不必要元素大量降解的过程，在癌症、动脉粥样硬化和神经退行性疾病等许多疾病中经常失调。因此，自噬调节剂具有成为自噬相关疾病治疗剂的巨大潜力。在这里，我们报告抗抑郁药舍曲林 (Sert) 是一种自噬诱导剂。从机制上讲，Sert 可能与线粒体 VDAC1（电压依赖性阴离子通道 1）结合并拮抗，导致细胞 ATP（三磷酸腺苷）水平降低，激活 AMP 活化蛋白激酶 (AMPK) 并抑制其下游 MTOR（机械靶点）雷帕霉素激酶）-RPS6KB1（核糖体蛋白 S6 激酶 B1）信号通路。缺乏 VDAC1 表达的细胞完全消除了 Sert 对 AMPK-MTOR 通路和自噬诱导活性的调节作用。我们进一步表明，Sert 通过诱导自噬促进 MAPT（微管相关蛋白 tau）蛋白的自噬降解，从而抑制 tauopathy。我们的研究证明了 Sert 作为一种新型小分子自噬诱导剂的潜力，并为通过靶向 VDAC1 治疗自噬相关疾病提供了一种新的候选药物。

缩写： AMP：一磷酸腺苷；AMPK：AMP激活的蛋白激酶；ATP：三磷酸腺苷；Baf：巴弗洛霉素A ₁; BiFC：生物分子荧光互补；CAMKK2/CAMKKB：钙/钙调蛋白依赖性蛋白激酶激酶 2；CC：化合物C；DARTS：药物亲和力反应靶点稳定性；HUVECs：人脐静脉内皮细胞；Inda：吲达曲林；STK11/LKB1：丝氨酸/苏氨酸激酶 11；MAPT：微管相关蛋白 tau；MAP1LC3/LC3：微管相关蛋白1轻链3；3-MA：3-甲基腺嘌呤；MEFs：小鼠胚胎成纤维细胞；MTOR：雷帕霉素激酶的机制靶点；PI3K：磷酸肌醇 3-激酶；拉帕：雷帕霉素；Sert：舍曲林；RPS6KB1：核糖体蛋白 S6 激酶 B1；SQSTM1/p62：隔离体 1；SLC6A4/SERT1：溶质载体家族 6 成员 4；TFEB：转录因子EB；VDAC1：电压依赖性阴离子通道 1；WT：野生型；WM：渥曼青霉素。