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Zhao J, Zheng Y, Xue F, Chang Y, Yang H, Zhang J. Molecular basis of reactive oxygen species-induced inactivation of α4β2 nicotinic acetylcholine receptors. Free Radic Biol Med 2016; 97:520-530. [PMID: 27445102 DOI: 10.1016/j.freeradbiomed.2016.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 07/03/2016] [Accepted: 07/16/2016] [Indexed: 01/11/2023]
Abstract
The α4β2 neuronal nicotinic acetylcholine receptors (nAChRs) are the most widespread heteromeric nAChR subtype in the brain, mediating fast synaptic transmission. Previous studies showed that α4β2 nAChRs could be inactivated by reactive oxygen species (ROS), but the underlying mechanism is still obscure. We found that H2O2 induced the rundown of ACh-evoked currents in human α4β2 nAChRs and the replacement of the conserved cysteine in the M1-M2 linker of either α4 Cys245 or β2 Cys237 with an alanine residue could prevent the current rundown. Structurally, α4 Cys245 and β2 Cys237 are hypothesized to be in close proximity when the receptor is activated. Western blotting results showed that α4 and β2 subunits were cross-linked when the agonist-bound receptor encountered H2O2, which could be prevented by the substitution of the conserved cysteine in the M1-M2 linker to an alanine. Thus, when agonist bound to the receptor, α4 Cys245 and β2 Cys237 came close to each other and ROS oxidized these conserved cysteines, leading subunits to be cross-linked and trapping α4β2 nAChRs into the inactivation state. In addition, we mimicked an experimental Parkinson's disease (PD) model in PC12 cells and found that ROS, generated by 6-hydroxydopamine (6-OHDA), could cause the current rundown in α4β2 nAChRs, which may play a role in PD.
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Affiliation(s)
- Junjun Zhao
- Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Center of Neural Regeneration and Repair, Beijing Key Laboratory of Brain Major Disorders-State Key Lab Incubation Base, Beijing Neuroscience Disciplines, Beijing 100069, China
| | - Yan Zheng
- Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Center of Neural Regeneration and Repair, Beijing Key Laboratory of Brain Major Disorders-State Key Lab Incubation Base, Beijing Neuroscience Disciplines, Beijing 100069, China
| | - Fenqin Xue
- Medical Experiment and Test Center, Capital Medical University, Beijing 100069, China
| | - Yongchang Chang
- Division of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, USA
| | - Hui Yang
- Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Center of Neural Regeneration and Repair, Beijing Key Laboratory of Brain Major Disorders-State Key Lab Incubation Base, Beijing Neuroscience Disciplines, Beijing 100069, China.
| | - Jianliang Zhang
- Department of Neurobiology, Beijing Institute of Brain Disorders, Capital Medical University, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Center of Neural Regeneration and Repair, Beijing Key Laboratory of Brain Major Disorders-State Key Lab Incubation Base, Beijing Neuroscience Disciplines, Beijing 100069, China.
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2
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Wang XY, Yang HW. Upregulation of CBS/H2S system contributes to asymmetric dimethylarginine-triggered protection against the neurotoxicity of glutamate to PC12 cells by inhibiting NOS/NO pathway. Exp Cell Res 2016; 346:111-8. [PMID: 27321959 DOI: 10.1016/j.yexcr.2016.06.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/02/2016] [Accepted: 06/14/2016] [Indexed: 11/27/2022]
Abstract
Glutamate-induced neurotoxicity involves in overproduction of nitric oxide (NO) and oxidative stress. Our previous data demonstrated that asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, has a protective effect against glutamate-induced neurotoxicity. Hydrogen sulfide (H2S), the third endogenous gaseous mediator, has potential therapeutic value for oxidative stress-induced neural damage. Therefore, we hypothesized that ADMA provides protection against the neurotoxicity of glutamate by regulating endogenous H2S generation. In the present study, we found that ADMA prevented glutamate-triggered decrease in endogenous H2S generation in PC12 cells and reversed glutamate-induced suppression in the expression and activity of cystathionine-β-synthetase (CBS), the predominant enzymatic source of H2S in PC12 cells. Furthermore, AOAA, a potent inhibitor of CBS, significantly abolished the protective action of ADMA against glutamate-induced neurotoxicity to PC12 cells. We also showed that ADMA suppressed glutamate-elicited NOS excessive activation and NO overproduction in PC12 cells. These data indicate that the protection of ADMA against glutamate-induced neurotoxicity is by promoting endogenous H2S generation, resulting from suppression in NOS excessive activation and NO overproduction. These findings provide a novel mechanism underlying the protection of ADMA against glutamate-induced neurotoxicity.
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Affiliation(s)
- Xiang-Yu Wang
- Department of Neurology, Third Clinical Hospital, China Three Gorges University, 60 Qiaohu 1st Road, 443002 Yichang, PR China; Department of Neurology, Gezhouba Central Hospital, 443002 Yichang, PR China.
| | - Hong-Wei Yang
- Department of Physiology, college of medical sciences, China Three Gorges University, 443002 Yichang, PR China
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3
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Hou XL, Chen Y, Yin H, Duan WG. Combination of fasudil and celecoxib promotes the recovery of injured spinal cord in rats better than celecoxib or fasudil alone. Neural Regen Res 2016; 10:1836-40. [PMID: 26807121 PMCID: PMC4705798 DOI: 10.4103/1673-5374.170314] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Resistance mechanisms of rho-associated kinase (ROCK) inhibitors are associated with the enhanced expression of cyclooxygenase-2 (COX-2). The therapeutic effects of ROCK on nervous system diseases might be enhanced by COX-2 inhibitors. This study investigated the synergistic effect of the combined use of the ROCK inhibitor fasudil and a COX-2 inhibitor celecoxib on spinal cord injury in a rat model established by transecting the right half of the spinal cord at T11. Rat models were orally administrated with celecoxib (20 mg/kg) and/or intramuscularly with fasudil (10 mg/kg) for 2 weeks. Results demonstrated that the combined use of celecoxib and fasudil significantly decreased COX-2 and Rho kinase II expression surrounding the lesion site in rats with spinal cord injury, improved the pathomorphology of the injured spinal cord, and promoted the recovery of motor function. Moreover, the effects of the drug combination were better than celecoxib or fasudil alone. This study demonstrated that the combined use of fasudil and celecoxib synergistically enhanced the functional recovery of injured spinal cord in rats.
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Affiliation(s)
- Xiao-Lin Hou
- Key Laboratory of Molecular Biology for Sinomedicine, Yunnan Key Laboratory for Enthnomedicine, Kunming, Yunnan Province, China
| | - Yan Chen
- Key Laboratory of Molecular Biology for Sinomedicine, Yunnan Key Laboratory for Enthnomedicine, Kunming, Yunnan Province, China
| | - Hua Yin
- Key Laboratory of Molecular Biology for Sinomedicine, Yunnan Key Laboratory for Enthnomedicine, Kunming, Yunnan Province, China
| | - Wei-Gang Duan
- Key Laboratory of Molecular Biology for Sinomedicine, Yunnan Key Laboratory for Enthnomedicine, Kunming, Yunnan Province, China; Initiative Team of Microenvironment, Yunnan University of Traditional Chinese Medicine, Kunming, Yunnan Province, China
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4
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Effects of various pharmacological agents on the function of norepinephrine transporter. J UOEH 2015; 37:33-42. [PMID: 25787100 DOI: 10.7888/juoeh.37.33] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The norepinephrine transporter is selectively expressed in noradrenergic nerve terminals, where it can exert spatial and temporal control over the action of norepinephrine. The norepinephrine transporter mediates the termination of neurotransmission via the reuptake of norepinephrine released into the extracellular milieu. In the present brief review, we report our recent studies about the effects of various pharmacological agents such as fasudil, nicotine, pentazocine, ketamine and genistein on norepinephrine transporter function.
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Yin H, Hou X, Tao T, Lv X, Zhang L, Duan W. Neurite outgrowth resistance to rho kinase inhibitors in PC12 Adh cell. Cell Biol Int 2015; 39:563-76. [PMID: 25571866 DOI: 10.1002/cbin.10423] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 12/26/2014] [Indexed: 01/21/2023]
Abstract
Rho kinase (ROCK) inhibitor is a promising agent for neural injury disorders, which mechanism is associated with neurite outgrowth. However, neurite outgrowth resistance occurred when PC12 Adh cell was treated with ROCK inhibitors for a longer time. PC12 Adh cells were treated with ROCK inhibitor Y27632 or NGF for different durations. Neurite outgrowth resistance occurred when PC12 Adh cell exposed to Y27632 (33 µM) for 3 or more days, but not happen when exposed to nerve growth factor (NGF, 100 ng/mL). The gene expression in the PC12 Adh cells treated with Y27632 (33 µM) or NGF (100 ng/mL) for 2 or 4 days was assayed by gene microarray, and the reliability of the results were confirmed by real-time RT-PCR. Cluster analysis proved that the gene expression profile of PC12 Adh cell treated with Y27632 for 4 days was different from that treated with Y27632 for 2 days and those treated with NGF for 2 and 4 days, respectively. Pathway analysis hinted that the neurite outgrowth resistance could be associated with up-regulation of inflammatory pathways, especially rno04610 (complement and coagulation cascades), and down-regulation of cell cycle pathways, especially rno04110.
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Affiliation(s)
- Hua Yin
- Key Laboratory of Molecular Biology for Sinomedicine, Yunnan University of Traditional Chinese Medicine, 1076, Yuhua Road, University City of Chenggong, Kunming, 650500, China
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Duan W, Que L, Lv X, Li Q, Yin H, Zhang L. Tolerance of neurite outgrowth to Rho kinase inhibitors decreased by cyclooxygenase-2 inhibitor. Neural Regen Res 2014; 7:2705-12. [PMID: 25337117 PMCID: PMC4200739 DOI: 10.3969/j.issn.1673-5374.2012.34.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 07/24/2012] [Indexed: 11/21/2022] Open
Abstract
In this study, PC12 Adh cells and Neuro-2a cells were treated with Rho-associated kinase inhibitors (Y27632 and Fasudil), a cyclooxygenase-1 selective inhibitor (SC560), and a cyclooxygenase-2 inhibitor (NS398). We found that these cells became tolerant to Rho-associated kinase inhibitors, as neurite outgrowth induced by these inhibitors diminished following more than 3 days of exposure in either cell line. The proteins cyclooxygenase-2 and cytosolic prostaglandin E synthetase were upregulated at day 3. NS398 decreased the tolerance to neurite outgrowth induction in both cell lines, whereas SC560 had almost no effect. These findings indicate that cells become tolerant to neurite outgrowth induced by Rho-associated kinase inhibitors, this is at least partly associated with upregulation of proteins involved in the cyclooxygenase-2 pathway, and cyclooxygenases-2 inhibition prevents this tolerance.
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Affiliation(s)
- Weigang Duan
- Key Laboratory of Molecular Biology for Sinomedicine, Yunnan University of Traditional Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Ling Que
- Key Laboratory of Molecular Biology for Sinomedicine, Yunnan University of Traditional Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Xiaoman Lv
- Key Laboratory of Molecular Biology for Sinomedicine, Yunnan University of Traditional Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Qifeng Li
- Key Laboratory of Molecular Biology for Sinomedicine, Yunnan University of Traditional Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Hua Yin
- Key Laboratory of Molecular Biology for Sinomedicine, Yunnan University of Traditional Chinese Medicine, Kunming 650500, Yunnan Province, China
| | - Luyong Zhang
- New Drug Screening Center, China Pharmaceutical University, Nanjing 210009, Jiangsu Province, China
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Li X, Zhang KY, Zhang P, Chen LX, Wang L, Xie M, Wang CY, Tang XQ. Hydrogen sulfide inhibits formaldehyde-induced endoplasmic reticulum stress in PC12 cells by upregulation of SIRT-1. PLoS One 2014; 9:e89856. [PMID: 24587076 PMCID: PMC3938548 DOI: 10.1371/journal.pone.0089856] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 01/23/2014] [Indexed: 12/29/2022] Open
Abstract
Background Formaldehyde (FA), a well-known environmental pollutant, has been classified as a neurotoxic molecule. Our recent data demonstrate that hydrogen sulfide (H2S), the third gaseous transmitter, has a protective effect on the neurotoxicity of FA. However, the exact mechanisms underlying this protection remain largely unknown. Endoplasmic reticulum (ER) stress has been implicated in the neurotoxicity of FA. Silent mating type information regulator 2 homolog 1 (SIRT-1), a histone deacetylases, has various biological activities, including the extension of lifespan, the modulation of ER stress, and the neuroprotective action. Objective We hypothesize that the protection of H2S against FA-induced neurotoxicity involves in inhibiting ER stress by upregulation of SIRT-1. The present study attempted to investigate the protective effect of H2S on FA-induced ER stress in PC12 cells and the contribution of SIRT-1 to the protection of H2S against FA-induced injuries, including ER stress, cytotoxicity and apoptosis. Principal Findings We found that exogenous application of sodium hydrosulfide (NaHS; an H2S donor) significantly attenuated FA-induced ER stress responses, including the upregulated levels of glucose-regulated protein 78, C/EBP homologous protein, and cleaved caspase-12 expression. We showed that NaHS upregulates the expression of SIRT-1 in PC12 cells. Moreover, the protective effects of H2S on FA-elicited ER stress, cytotoxicity and apoptosis were reversed by Sirtinol, a specific inhibitor of SIRT-1. Conclusion/Significance These data indicate that H2S exerts its protection against the neurotoxicity of FA through overcoming ER stress via upregulation of SIRT-1. Our findings provide novel insights into the protective mechanisms of H2S against FA-induced neurotoxicity.
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Affiliation(s)
- Xiang Li
- Department of Anesthesiology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- Department of Neurology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
| | - Kai-Yan Zhang
- Department of Neurology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- Institute of Neuroscience, Medical College, University of South China, Hengyang, Hunan, P. R. China
| | - Ping Zhang
- Department of Neurology, Nanhua Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
| | - Li-Xun Chen
- Department of Neurology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
| | - Li Wang
- Department of Anthropotomy, Medical College, University of South China, Hengyang, Hunan, P.R. China
| | - Ming Xie
- Department of Anesthesiology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- Department of Neurology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- * E-mail: (X-QT); (MX)
| | - Chun-Yan Wang
- Department of Pathophysiology, Medical College, University of South China, Hengyang, Hunan, P.R. China
| | - Xiao-Qing Tang
- Department of Anesthesiology, the First Affiliated Hospital, University of South China, Hengyang, Hunan, P. R. China
- Institute of Neuroscience, Medical College, University of South China, Hengyang, Hunan, P. R. China
- * E-mail: (X-QT); (MX)
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8
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Han X, Zhu S, Wang B, Chen L, Li R, Yao W, Qu Z. Antioxidant action of 7,8-dihydroxyflavone protects PC12 cells against 6-hydroxydopamine-induced cytotoxicity. Neurochem Int 2014; 64:18-23. [DOI: 10.1016/j.neuint.2013.10.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 10/09/2013] [Accepted: 10/31/2013] [Indexed: 01/10/2023]
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9
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Wang XY, Zhao J, Yang HW. Asymmetrical dimethylarginine antagonizes glutamate-induced apoptosis in PC12 cells. J Mol Neurosci 2012; 49:89-95. [PMID: 23054590 DOI: 10.1007/s12031-012-9897-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 09/25/2012] [Indexed: 12/21/2022]
Abstract
Overproduction of nitric oxide (NO) plays an important role in glutamate-induced excitotoxicity. Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide synthase (NOS) inhibitor. The aim of this study is to explore whether ADMA antagonizes the excitotoxicity of glutamate to neuronal cells and the underlying molecular mechanisms. In this work, we investigated the effects of ADMA on glutamate-induced toxicity in neuronal cells by studying PC12 cells, a clonal rat pheochromocytoma cell line. We show that ADMA obviously protects PC12 cells against glutamate-induced cytotoxicity and apoptosis. We also found that ADMA treatment results in prevention of glutamate-induced mitochondrial membrane potential loss and caspase-3 activation. Moreover, ADMA prevents glutamate-caused down-regulation of bcl-2 protein expression. These results indicate that ADMA protects against glutamate-induced apoptosis and excitotoxicity and the underlying mechanism may be involved in preservation of mitochondrial function by up-regulating the expression of bcl-2. Our study suggests a promising future of ADMA-based therapies for neuropathologies associated with an excess of NO.
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Affiliation(s)
- Xiang-Yu Wang
- Department of Neurology, Third Clinical Hospital, China Three Gorges University, 60 Qiaohu 1st Road, 443002 Yichang, China.
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Stimulation of norepinephrine transporter function by fasudil, a Rho kinase inhibitor, in cultured bovine adrenal medullary cells. Naunyn Schmiedebergs Arch Pharmacol 2012; 385:921-31. [PMID: 22752240 DOI: 10.1007/s00210-012-0773-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 06/14/2012] [Indexed: 12/13/2022]
Abstract
Norepinephrine transporter (NET) regulates noradrenergic synaptic transmission by controlling extracellular levels of norepinephrine (NE). The small GTPase, RhoA, and its downstream effector Rho kinase (ROCK) are involved in the regulation of actin cytoskeleton and focal adhesion/stress fiber formation, which may play an important role in various functions of the sympathetic nervous system. We report here the effect of fasudil, a ROCK inhibitor, on the functions of NET in cultured bovine adrenal medullary cells as a model of sympathetic neurons. Treatment of bovine adrenal medullary cells with fasudil caused an increase in [(3)H]NE uptake in time (8-120 h) and concentration (10-100 μM)-dependent manner. Another ROCK inhibitor, Y-27632 (10-100 μM, 1 day), also increased [(3)H]NE uptake by the cells. Kinetics analysis of the effect of fasudil on NE transport showed a significant increase in the V (max) of NE transport with little change in K (m). When both extracellular and intracellular Ca(2+) were removed by the deprivation of extracellular Ca(2+) and BAPTA-AM, a cell-permeable Ca(2+) chelator, [(3)H]NE uptake induced by fasudil was completely abolished. Nocodazole, an inhibitor of microtubule polymerization, but not cytochalasin D, an inhibitor of actin polymerization, suppressed the stimulatory effect of fasudil on [(3)H]NE uptake. The present findings suggest that the ROCK inhibitor fasudil up-regulates NET function in a Ca(2+)-dependent and/or nocodazole-sensitive pathway in adrenal medullary cells.
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Hydrogen sulfide prevents formaldehyde-induced neurotoxicity to PC12 cells by attenuation of mitochondrial dysfunction and pro-apoptotic potential. Neurochem Int 2012; 61:16-24. [PMID: 22542418 DOI: 10.1016/j.neuint.2012.04.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 04/08/2012] [Accepted: 04/11/2012] [Indexed: 11/23/2022]
Abstract
Hydrogen sulfide (H(2)S) has been shown to act as a neuroprotectant and antioxidant. Numerous studies have demonstrated that exposure to formaldehyde (FA) causes neuronal damage and that oxidative stress is one of the most critical effects of FA exposure. Accumulation of FA is involved in the pathogenesis of Alzheimer's disease (AD). The aim of present study is to explore the inhibitory effects of H(2)S on FA-induced cytotoxicity and apoptosis and the molecular mechanisms underlying in PC12 cells. We show that sodium hydrosulfide (NaHS), a H(2)S donor, protects PC12 cells against FA-mediated cytotoxicity and apoptosis and that NaHS preserves the function of mitochondria by preventing FA-induced loss of mitochondrial membrane potential and release of cytochrome c in PC12 cells. Furthermore, NaHS blocks FA-exerted accumulation of intracellular reactive oxygen species (ROS), down-regulation of Bcl-2 expression, and up-regulation of Bax expression. These results indicate that H(2)S protects neuronal cells against neurotoxicity of FA by preserving mitochondrial function through attenuation of ROS accumulation, up-regulation of Bcl-2 level, and down-regulation of Bax expression. Our study suggests a promising future of H(2)S-based preventions and therapies for neuronal damage after FA exposure.
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12
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Tang XQ, Chen RQ, Ren YK, Soldato PD, Sparatore A, Zhuang YY, Fang HR, Wang CY. ACS6, a Hydrogen sulfide-donating derivative of sildenafil, inhibits homocysteine-induced apoptosis by preservation of mitochondrial function. Med Gas Res 2011; 1:20. [PMID: 22146536 PMCID: PMC3231821 DOI: 10.1186/2045-9912-1-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 08/16/2011] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The hydrogen sulfide-releasing sildenafil, ACS6, has been demonstrated to inhibit superoxide formation through donating hydrogen sulfide (H2S). We have found that H2S antagonizes homocysteine-induced oxidative stress and neurotoxicity. The aim of the present study is to explore the protection of ACS6 against homocysteine-triggered cytotoxicity and apoptosis and the molecular mechanisms underlying in PC12 cells. METHODS Cell viability was determined by Cell Counting Kit-8 assay. Cell apoptosis was observed using the chromatin dye Hoechst 33258 and analyzed by Flow Cytometry after propidium iodide staining. Mitochondrial membrane potential was monitored using the fluorescent dye Rh123. Intracellular reactive oxygen species were determined by oxidative conversion of cell permeable 2',7'-dichlorfluorescein-diacetate to fluorescent 2',7'-dichlorfluorescein. The expression of cleaved caspase-3 and bcl-2 and the accumulation of cytosolic cytochrome c were analyzed by Western blot. RESULTS We show that ACS6 protects PC12 cells against cytotoxicity and apoptosis induced by homocysteine and blocks homocysteine-triggered cytochrome c release and caspase-3 activation. ACS6 treatment results in not only prevention of homocysteine-caused mitochondrial membrane potential (Δψ) loss and reactive oxygen species (ROS) overproduction but also reversal of Bcl-2 down-expression. CONCLUSIONS These results indicate that ACS6 protects PC12 cells against homocysteine-induced cytotoxicity and apoptosis by preservation of mitochondrial function though inhibiting both loss of Δψ and accumulation of ROS as well as modulating the expression of Bcl-2. Our study provides evidence both for a neuroprotective effect of ACS6 and for further evaluation of ACS6 as novel neuroprotectants for Alzheimer's disease associated with homocysteine.
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Affiliation(s)
- Xiao-Qing Tang
- Department of Physiology, Medical College, University of South China, Hengyang, 421001, Hunan, P.R. China
| | - Rong-Qian Chen
- Department of Physiology, Medical College, University of South China, Hengyang, 421001, Hunan, P.R. China
| | - Yan-Kai Ren
- Department of Physiology, Medical College, University of South China, Hengyang, 421001, Hunan, P.R. China
| | | | - Anna Sparatore
- Department of Pharmaceutical Sciences "Pietro Pratesi", Università degli Studi di Milano, Milan, Italy
| | - Yuan-Yuan Zhuang
- Department of Physiology, Medical College, University of South China, Hengyang, 421001, Hunan, P.R. China
| | - Hen-Rong Fang
- Department of Physiology, Medical College, University of South China, Hengyang, 421001, Hunan, P.R. China
| | - Chun-Yan Wang
- Department of Pathophysiology, Medical College,, University of south China, Hengyang, 421001, Hunan, P.R. China
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13
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Tang XQ, Ren YK, Chen RQ, Zhuang YY, Fang HR, Xu JH, Wang CY, Hu B. Formaldehyde induces neurotoxicity to PC12 cells involving inhibition of paraoxonase-1 expression and activity. Clin Exp Pharmacol Physiol 2011; 38:208-14. [PMID: 21261675 DOI: 10.1111/j.1440-1681.2011.05485.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
1. Formaldehyde (FA) has been found to cause toxicity to neurons. However, its neurotoxic mechanisms have not yet been clarified. Increasing evidence has shown that oxidative damage is one of the most critical effects of formaldehyde exposure. Paraoxonase-1 (PON-1) is a pivotal endogenous anti-oxidant. Thus, we hypothesized that FA-mediated downregulation of PON1 is associated with its neurotoxicity. 2. In the present work, we used PC12 cells to study the neurotoxicity of FA and explore whether PON-1 is implicated in FA-induced neurotoxicity. 3. We found that FA has potent cytotoxic and apoptotic effects on PC12 cells. FA induces an accumulation of intracellular reactive oxygen species along with downregulation of Bcl-2 expression, as well as increased cytochrome c release. FA significantly suppressed the expression and activity of PON-1 in PC12 cells. Furthermore, H(2)S, an endogenous anti-oxidant gas, antagonizes FA-induced cytotoxicity as well as 2-hydroxyquinoline, a specific inhibitor of PON-1, which also induces cytotoxicity to PC12 cells. 4. The results of the present study provide, for the first time, evidence that the inhibitory effect on PON-1 expression and activity is involved in the neurotoxicity of FA, and suggest a promising role of PON-1 as a novel therapeutic strategy for FA-mediated toxicity.
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Affiliation(s)
- Xiao-Qing Tang
- Department of Physiology, Medical College, University of South China, Hengyang, Hunan, China.
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14
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Endogenous Hydrogen Sulfide is Involved in Asymmetric Dimethylarginine-induced Protection Against Neurotoxicity of 1-Methyl-4-phenyl-pyridinium Ion. Neurochem Res 2011; 36:2176-85. [DOI: 10.1007/s11064-011-0542-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2011] [Indexed: 01/21/2023]
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15
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Tang XQ, Shen XT, Huang YE, Chen RQ, Ren YK, Fang HR, Zhuang YY, Wang CY. Inhibition of endogenous hydrogen sulfide generation is associated with homocysteine-induced neurotoxicity: role of ERK1/2 activation. J Mol Neurosci 2010; 45:60-7. [PMID: 21104457 DOI: 10.1007/s12031-010-9477-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 11/07/2010] [Indexed: 12/01/2022]
Abstract
Both elevated homocysteine and decreased hydrogen sulfide (H(2)S) are observed in the brains of Alzheimer's disease (AD) patients. Reactive oxygen species (ROS) overproduction contributes to the neurotoxicity of homocysteine; however, H(2)S is an endogenous antioxidant gas. Therefore, the aim of this study was to investigate whether the imbalance of proportion to this endogenous protective antioxidant gas is involved in homocysteine-caused neurotoxicity. We show that homocysteine inhibits the generation of endogenous H(2)S and the expression and activity of cystathionine-β-synthetase (CBS), the main enzyme responsible for the generation of H(2)S in PC12 cells. S-Adenosylmethionine, an activator of CBS, not only prevents homocysteine-induced inhibition of endogenous H(2)S production but also attenuates homocysteine-triggered cytotoxicity and accumulation of ROS. We find that activation of ERK1/2 occurs in homocysteine-treated PC12 cells and blockade of ERK1/2 with U0126 abolished the homocysteine-induced cytotoxicity and inhibitory effect on endogenous H(2)S generation. These results indicate that homocysteine neurotoxicity involves reduction of H(2)S production, which is caused by inhibition of CBS and mediated by activation of ERK1/2. Our study suggests a promising future of H(2)S-based therapies for neurodegenerative diseases such as AD.
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Affiliation(s)
- Xiao-Qing Tang
- Department of Physiology, Medical College, University of South China, 28 W Changsheng Road, Hengyang, 421001, Hunan, People's Republic of China,
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Hydrogen sulfide antagonizes homocysteine-induced neurotoxicity in PC12 cells. Neurosci Res 2010; 68:241-9. [DOI: 10.1016/j.neures.2010.07.2039] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 06/02/2010] [Accepted: 07/21/2010] [Indexed: 01/15/2023]
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Kaizaki A, Tanaka S, Tsujikawa K, Numazawa S, Yoshida T. Recreational drugs, 3,4-Methylenedioxymethamphetamine(MDMA), 3,4-methylenedioxyamphetamine (MDA) and diphenylprolinol, inhibit neurite outgrowth in PC12 cells. J Toxicol Sci 2010; 35:375-81. [DOI: 10.2131/jts.35.375] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Asuka Kaizaki
- Department of Biochemical Toxicology, School of Pharmacy, Showa University
| | - Sachiko Tanaka
- Department of Biochemical Toxicology, School of Pharmacy, Showa University
| | | | - Satoshi Numazawa
- Department of Biochemical Toxicology, School of Pharmacy, Showa University
| | - Takemi Yoshida
- Department of Biochemical Toxicology, School of Pharmacy, Showa University
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