title: Effects of DDIT4 in Methamphetamine-Induced Autophagy and Apoptosis in Dopaminergic Neurons.
abstract: Methamphetamine (METH) is an illicit psychoactive drug that can cause a variety of detrimental effects to the nervous system, especially dopaminergic pathways. We hypothesized that DNA damage-inducible transcript 4 (DDIT4) is involved in METH-induced dopaminergic neuronal autophagy and apoptosis. To test the hypothesis, we determined changes of DDIT4 protein expression and the level of autophagy in rat catecholaminergic PC12 cells and human dopaminergic SH-SY5Y cells, and in the hippocampus, prefrontal cortex, and striatum of Sprague Dawley rats exposed to METH. We also examined the effects of silencing DDIT4 expression on METH-induced dopaminergic neuronal autophagy using fluorescence microscopy and electron microscopy. Flow cytometry and Western blot were used to determine apoptosis and the expression of apoptotic markers (cleaved caspase-3 and cleaved PARP) after blocking DDIT4 expression in PC12 cells and SH-SY5Y cells with synthetic siRNA, as well as in the striatum of rats by injecting LV-shDDIT4 lentivirus using a stereotaxic positioning system. Our results showed that METH exposure increased DDIT4 expression that was accompanied with increased autophagy and apoptosis in PC12 cells (3 mM) and SH-SY5Y cells (2 mM), and in the hippocampus, prefrontal cortex, and striatum of rats. Inhibition of DDIT4 expression reduced METH-induced autophagy and apoptosis in vitro and in vivo. However, DDIT4-related effects were not observed at a low concentration of METH (1 μM). These results suggest that DDIT4 plays an essential role in METH-induced dopaminergic neuronal autophagy and apoptosis at higher doses and may be a potential gene target for therapeutics in high-dose METH-induced neurotoxicity.
authors.affiliation: Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou, 510515, People's Republic of China.
authors.forename: Bing
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou, 510515, People's Republic of China.|Department of Forensic Medicine, Guangdong Medical University, Dongguan, 523808, People's Republic of China.
authors.forename: Rui
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou, 510515, People's Republic of China.
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou, 510515, People's Republic of China.
authors.forename: Pingming
authors.initials: P
authors.lastname: Qiu
authors.affiliation: Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou, 510515, People's Republic of China.
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Ai
authors.affiliation: Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou, 510515, People's Republic of China.
authors.forename: Enping
authors.initials: E
authors.lastname: Huang
authors.affiliation: Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou, 510515, People's Republic of China.
authors.forename: Weiye
authors.initials: W
authors.lastname: Huang
authors.affiliation: Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou, 510515, People's Republic of China.
authors.forename: Chuanxiang
authors.initials: C
authors.lastname: Chen
authors.affiliation: Guangzhou Forensic Science Institute, Guangzhou, 510030, People's Republic of China.
authors.forename: Chao
authors.initials: C
authors.lastname: Liu
authors.affiliation: Institute of Computational Comparative Medicine and Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA.
authors.forename: Zhoumeng
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou, 510515, People's Republic of China. xwb@smu.edu.cn.
authors.forename: Wei-Bing
authors.initials: WB
authors.lastname: Xie
authors.affiliation: Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou, 510515, People's Republic of China. hjwang711@yahoo.cn.
authors.forename: Huijun
authors.initials: H
authors.lastname: Wang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001343:Autophagy / Q000187:drug effects / Q000502:physiology*; D059290:Dopaminergic Neurons / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008297:Male; D008694:Methamphetamine / Q000633:toxicity*; D016716:PC12 Cells; D051381:Rats; D017207:Rats, Sprague-Dawley; D014157:Transcription Factors / Q000096:biosynthesis*
chemical_list: C469991:DDIT4 protein, human; D014157:Transcription Factors; D008694:Methamphetamine
keywords: Apoptosis; Autophagy; DNA damage-inducible transcript 4 (DDIT4); Dopamine; Methamphetamine; Neurotoxicity