Zi-Qiang Shao1,2,3, Xiong Zhang1, Hui-Hui Fan2, Xiao-Shuang Wang2, Hong-Mei Wu2, Li Zhang4,5, Wen-Hsing Cheng4, Jian-Hong Zhu1,2. 1. Department of Geriatrics and Neurology, the Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China. 2. Department of Preventive Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, China. 3. Department of Critical Care Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, China. 4. Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Mississippi State, MS, USA. 5. Department of Poultry Science, Mississippi State University, Mississippi State, MS, USA.
Abstract
BACKGROUND: Selenium is prioritized to the brain mainly for selenoprotein expression. Selenoprotein T (SELENOT) protects dopaminergic, postmitotic neurons in a mouse model of Parkinson's disease (PD). OBJECTIVE: We hypothesized a proliferative role of SELENOT in neural cells. METHODS: To assess SELENOT status in PD, sedated male C57BL/6 mice at 10-12 wk of age were injected with 6-hydroxydopamine in neurons, and human peripheral blood mononuclear cells were isolated from 9 healthy subjects (56% men, 68-y-old) and 11 subjects with PD (64% men, 63-y-old). Dopaminergic neural progenitor-like SK-N-SH cells with transient SELENOT overexpression or knockdown were maintained in the presence or absence of the antioxidant N-acetyl-l-cysteine and the calcium channel blocker nimodipine. Cell cycle, proliferation, and signaling parameters were determined by immunoblotting, qPCR, and flow cytometry. RESULTS: SELENOT mRNA abundance was increased (P < 0.05) in SK-N-SH cells treated with 1-methyl-4-phenylpyridinium iodide (3.5-fold) and peripheral blood mononuclear cells from PD patients (1.6-fold). Likewise, SELENOT was expressed in tyrosine hydroxylase-positive dopaminergic neurons of 6-hydroxydopamine-injected mice. Knockdown of SELENOT in SK-N-SH cells suppressed (54%; P < 0.05) 5-ethynyl-2'-deoxyuridine incorporation but induced (17-47%; P < 0.05) annexin V-positive cells, CASPASE-3 cleavage, and G1/S cell cycle arrest. SELENOT knockdown and overexpression increased (88-120%; P < 0.05) and reduced (37-42%; P < 0.05) both forkhead box O3 and p27, but reduced (51%; P < 0.05) and increased (1.2-fold; P < 0.05) cyclin-dependent kinase 4 protein abundance, respectively. These protein changes were diminished by nimodipine or N-acetyl-l-cysteine treatment (24 h) at steady-state levels. While the N-acetyl-l-cysteine treatment did not influence the reduction in the amount of calcium (13%; P < 0.05) by SELENOT knockdown, the nimodipine treatment reversed the decreased amount of reactive oxygen species (33%; P < 0.05) by SELENOT overexpression. CONCLUSIONS: These cellular and mouse data link SELENOT to neural proliferation, expanding our understanding of selenium protection in PD.
BACKGROUND:Selenium is prioritized to the brain mainly for selenoprotein expression. Selenoprotein T (SELENOT) protects dopaminergic, postmitotic neurons in a mouse model of Parkinson's disease (PD). OBJECTIVE: We hypothesized a proliferative role of SELENOT in neural cells. METHODS: To assess SELENOT status in PD, sedated male C57BL/6 mice at 10-12 wk of age were injected with 6-hydroxydopamine in neurons, and human peripheral blood mononuclear cells were isolated from 9 healthy subjects (56% men, 68-y-old) and 11 subjects with PD (64% men, 63-y-old). Dopaminergic neural progenitor-like SK-N-SH cells with transient SELENOT overexpression or knockdown were maintained in the presence or absence of the antioxidant N-acetyl-l-cysteine and the calcium channel blocker nimodipine. Cell cycle, proliferation, and signaling parameters were determined by immunoblotting, qPCR, and flow cytometry. RESULTS:SELENOT mRNA abundance was increased (P < 0.05) in SK-N-SH cells treated with 1-methyl-4-phenylpyridinium iodide (3.5-fold) and peripheral blood mononuclear cells from PDpatients (1.6-fold). Likewise, SELENOT was expressed in tyrosine hydroxylase-positive dopaminergic neurons of 6-hydroxydopamine-injected mice. Knockdown of SELENOT in SK-N-SH cells suppressed (54%; P < 0.05) 5-ethynyl-2'-deoxyuridine incorporation but induced (17-47%; P < 0.05) annexin V-positive cells, CASPASE-3 cleavage, and G1/S cell cycle arrest. SELENOT knockdown and overexpression increased (88-120%; P < 0.05) and reduced (37-42%; P < 0.05) both forkhead box O3 and p27, but reduced (51%; P < 0.05) and increased (1.2-fold; P < 0.05) cyclin-dependent kinase 4 protein abundance, respectively. These protein changes were diminished by nimodipine or N-acetyl-l-cysteine treatment (24 h) at steady-state levels. While the N-acetyl-l-cysteine treatment did not influence the reduction in the amount of calcium (13%; P < 0.05) by SELENOT knockdown, the nimodipine treatment reversed the decreased amount of reactive oxygen species (33%; P < 0.05) by SELENOT overexpression. CONCLUSIONS: These cellular and mouse data link SELENOT to neural proliferation, expanding our understanding of selenium protection in PD.
Authors: Francis P Grenn; Jonggeol J Kim; Mary B Makarious; Hirotaka Iwaki; Anastasia Illarionova; Kajsa Brolin; Jillian H Kluss; Artur F Schumacher-Schuh; Hampton Leonard; Faraz Faghri; Kimberley Billingsley; Lynne Krohn; Ashley Hall; Monica Diez-Fairen; Maria Teresa Periñán; Jia Nee Foo; Cynthia Sandor; Caleb Webber; Brian K Fiske; J Raphael Gibbs; Mike A Nalls; Andrew B Singleton; Sara Bandres-Ciga; Xylena Reed; Cornelis Blauwendraat Journal: Mov Disord Date: 2020-08-31 Impact factor: 9.698