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Deng Z, Chen X, Zhang R, Kong L, Fang Y, Guo J, Shen B, Zhang L. Delta opioid peptide [D-ala2, D-leu5]-Enkephalin's ability to enhance mitophagy via TRPV4 to relieve ischemia/reperfusion injury in brain microvascular endothelial cells. Stroke Vasc Neurol 2024:svn-2023-003080. [PMID: 38697767 DOI: 10.1136/svn-2023-003080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 04/20/2024] [Indexed: 05/05/2024] Open
Abstract
BACKGROUND Local brain tissue can suffer from ischaemia/reperfusion (I/R) injury, which lead to vascular endothelial damage. The peptide δ opioid receptor (δOR) agonist [D-ala2, D-leu5]-Enkephalin (DADLE) can reduce apoptosis caused by acute I/R injury in brain microvascular endothelial cells (BMECs). OBJECTIVE This study aims to explore the mechanism by which DADLE enhances the level of mitophagy in BMECs by upregulating the expression of transient receptor potential vanilloid subtype 4 (TRPV4). METHODS BMECs were extracted and made to undergo oxygen-glucose deprivation/reoxygenation (OGD/R) accompanied by DADLE. RNA-seq analysis revealed that DADLE induced increased TRPV4 expression. The CCK-8 method was used to assess the cellular viability; quantitative PCR (qPCR) was used to determine the mRNA expression of Drp1; western blot was used to determine the expression of TRPV4 and autophagy-related proteins; and calcium imaging was used to detect the calcium influx. Autophagosomes in in the cells' mitochondria were observed by using transmission electron microscopy. ELISA was used to measure ATP content, and a JC-1 fluorescent probe was used to detect mitochondrial membrane potential. RESULTS When compared with the OGD/R group, OGD/R+DADLE group showed significantly enhanced cellular viability; increased expression of TRPV4, Beclin-1, LC3-II/I, PINK1 and Parkin; decreased p62 expression; a marked rise in calcium influx; further increases in mitophagy, an increase in ATP synthesis and an elevation of mitochondrial membrane potential. These protective effects of DADLE can be blocked by a TRPV4 inhibitor HC067047 or RNAi of TRPV4. CONCLUSION DADLE can promote mitophagy in BMECs through TRPV4, improving mitochondrial function and relieving I/R injury.
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Affiliation(s)
- Zhongfang Deng
- Department of Physiology, Anhui Medical University, Hefei, Anhui, China
| | - Xiaoyu Chen
- Department of Physiology, Anhui Medical University, Hefei, Anhui, China
| | - Ran Zhang
- Department of Physiology, Anhui Medical University, Hefei, Anhui, China
| | - Lingchao Kong
- Department of Orthopedics, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Yang Fang
- Department of Physiology, Anhui Medical University, Hefei, Anhui, China
| | - Jizheng Guo
- Department of Pathophysiology, Anhui Medical University, Hefei, Anhui, China
| | - Bing Shen
- Dr. Neher's Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao
| | - Lesha Zhang
- Department of Physiology, Anhui Medical University, Hefei, Anhui, China
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Alam MR, Singh S. Neuromodulation in Parkinson's disease targeting opioid and cannabinoid receptors, understanding the role of NLRP3 pathway: a novel therapeutic approach. Inflammopharmacology 2023:10.1007/s10787-023-01259-0. [PMID: 37318694 DOI: 10.1007/s10787-023-01259-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 05/26/2023] [Indexed: 06/16/2023]
Abstract
Parkinson's disease (PD) is a prevalent neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta, resulting in motor and non-motor symptoms. Although levodopa is the primary medication for PD, its long-term use is associated with complications such as dyskinesia and drug resistance, necessitating novel therapeutic approaches. Recent research has highlighted the potential of targeting opioid and cannabinoid receptors as innovative strategies for PD treatment. Modulating opioid transmission, particularly through activating µ (MOR) and δ (DOR) receptors while inhibiting κ (KOR) receptors, shows promise in preventing motor complications and reducing L-DOPA-induced dyskinesia. Opioids also possess neuroprotective properties and play a role in neuroprotection and seizure control. Similar to this, endocannabinoid signalling via CB1 and CB2 receptors influences the basal ganglia and may contribute to PD pathophysiology, making it a potential therapeutic target. In addition to opioid and cannabinoid receptor targeting, the NLRP3 pathway, implicated in neuroinflammation and neurodegeneration, emerges as another potential therapeutic avenue for PD. Recent studies suggest that targeting this pathway holds promise as a therapeutic strategy for PD management. This comprehensive review focuses on neuromodulation and novel therapeutic approaches for PD, specifically highlighting the targeting of opioid and cannabinoid receptors and the NLRP3 pathway. A better understanding of these mechanisms has the potential to enhance the quality of life for PD patients.
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Affiliation(s)
- Md Reyaz Alam
- Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, 142001, India
| | - Shamsher Singh
- Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, 142001, India.
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Baker Rogers J, Higa GM. Spoken and Unspoken Matters Regarding the Use of Opioids in Cancer. J Pain Res 2022; 15:909-924. [PMID: 35411188 PMCID: PMC8994621 DOI: 10.2147/jpr.s349107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 03/24/2022] [Indexed: 11/23/2022] Open
Affiliation(s)
- Janna Baker Rogers
- Sections of Geriatrics, Palliative Medicine and Hospice, Department of Medicine, School of Medicine, West Virginia University, Morgantown, WV, USA
| | - Gerald M Higa
- Departments of Clinical Pharmacy and Medicine, Schools of Pharmacy and Medicine, West Virginia University, Morgantown, WV, USA
- Correspondence: Gerald M Higa, Departments of Clinical Pharmacy and Medicine, Schools of Pharmacy and Medicine, West Virginia University, Morgantown, WV, USA, 26506, Email
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Xu Y, Chen R, Zhi F, Sheng S, Khiati L, Yang Y, Peng Y, Xia Y. δ-opioid Receptor, Microglia and Neuroinflammation. Aging Dis 2022; 14:778-793. [PMID: 37191426 DOI: 10.14336/ad.2022.0912] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 09/12/2022] [Indexed: 11/18/2022] Open
Abstract
Neuroinflammation underlies the pathophysiology of multiple age-related neurological disorders. Microglia, the resident immune cells of the central nervous system, are critically involved in neuroinflammatory regulation and neural survival. Modulating microglial activation is thus a promising approach to alleviate neuronal injury. Our serial studies have revealed a neuroprotective role of the δ-opioid receptor (DOR) in several acute and chronic cerebral injuries by regulating neuroinflammation and cellular oxidative stress. More recently, we found an endogenous mechanism for the inhibition of neuroinflammation is closely related to DOR's modulation of microglia. Our recent studies showed that DOR activation could strongly protect neurons from hypoxia- and lipopolysaccharide (LPS)-induced injury by inhibiting microglial pro-inflammatory transformation, while knocking-down DOR or restraining DOR activity promoted microglia activation and the relevant inflammatory events with an aggravation of cell injury. This novel finding highlights a therapeutic potential of DOR in numerous age-related neurological disorders through the modulation of neuroinflammation by targeting microglia. This review summarized the current data regarding the role of microglia in neuroinflammation, oxidative stress, and age-related neurological diseases focusing on the pharmacological effects and signaling transduction of DOR in microglia.
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Zhang G, Lai Z, Gu L, Xu K, Wang Z, Duan Y, Chen H, Zhang M, Zhang J, Zhao Z, Wang S. Delta Opioid Receptor Activation with Delta Opioid Peptide [d-Ala2, d-Leu5] Enkephalin Contributes to Synaptic Improvement in Rat Hippocampus against Global Ischemia. Cell Transplant 2021; 30:9636897211041585. [PMID: 34470528 PMCID: PMC8419564 DOI: 10.1177/09636897211041585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Global cerebral ischemia induced by cardiac arrest usually leads to poor neurological outcomes. Numerous studies have focused on ways to prevent ischemic damage in the brain, however clinical therapies are still limited. Our previous studies revealed that delta opioid receptor (DOR) activation with [d-Ala2, d-Leu5] enkephalin (DADLE), a DOR agonist, not only significantly promotes neuronal survival on day 3, but also improves spatial memory deficits on days 5-9 after ischemia. However, the neurological mechanism underlying DADLE-induced cognitive recovery remains unclear. This study first examined the changes in neuronal survival in the CA1 region at the advanced time point (day 7) after ischemia/reperfusion (I/R) injury and found a significant amelioration of damaged CA1 neurons in the rats treated with DADLE (2.5 nmol) when administered at the onset of reperfusion. The structure and function of CA1 neurons on days 3 and 7 post-ischemia showed significant improvements in both the density of the injured dendritic spines and the basic transmission of the impaired CA3-CA1 synapses following DADLE treatment. The molecular changes involved in DADLE-mediated synaptic modulation on days 3 and 7 post-ischemia implied the time-related differential regulation of PKCα-MARCKS on the dendritic spine structure and of BDNF- ERK1/2-synapsin I on synaptic function, in response to ischemic/reperfusion injury as well as to DADLE treatment. Importantly, all the beneficial effects of DADLE on ischemia-induced cellular, synaptic, and molecular deficits were eliminated by the DOR inhibitor naltrindole (2.5 nmol). Taken together, this study suggested that DOR activation-induced protective signaling pathways of PKCα-MARCKS involved in the synaptic morphology and BDNF-ERK-synapsin I in synaptic transmission may be engaged in the cognitive recovery in rats suffering from advanced cerebral ischemia.
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Affiliation(s)
- Guangming Zhang
- Department of Anesthesiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200336, China
| | - Zelin Lai
- Shanghai Key Laboratory of Brain Functional Genomics, Ministry of Education, School of Life Sciences, East China Normal University, Shanghai 200062, China
| | - Lingling Gu
- Shanghai Key Laboratory of Brain Functional Genomics, Ministry of Education, School of Life Sciences, East China Normal University, Shanghai 200062, China
| | - Kejia Xu
- Department of Anesthesiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200336, China
| | - Zhenlu Wang
- Shanghai Key Laboratory of Brain Functional Genomics, Ministry of Education, School of Life Sciences, East China Normal University, Shanghai 200062, China
| | - Yale Duan
- Shanghai Key Laboratory of Brain Functional Genomics, Ministry of Education, School of Life Sciences, East China Normal University, Shanghai 200062, China
| | - Huifen Chen
- Department of Clinical Laboratory, Shanghai First Maternity and Infant Hospital
| | - Min Zhang
- Tongji University School of Medicine, Shanghai 201204, China
| | - Jun Zhang
- Department of Clinical Laboratory, Shanghai First Maternity and Infant Hospital.,Tongji University School of Medicine, Shanghai 201204, China
| | - Zheng Zhao
- Shanghai Key Laboratory of Brain Functional Genomics, Ministry of Education, School of Life Sciences, East China Normal University, Shanghai 200062, China
| | - Shuyan Wang
- Department of Anesthesiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200336, China
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Altered mRNA Levels of Stress-Related Peptides in Mouse Hippocampus and Caudate-Putamen in Withdrawal after Long-Term Intermittent Exposure to Tobacco Smoke or Electronic Cigarette Vapour. Int J Mol Sci 2021; 22:ijms22020599. [PMID: 33435320 PMCID: PMC7827390 DOI: 10.3390/ijms22020599] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/02/2021] [Accepted: 01/06/2021] [Indexed: 02/06/2023] Open
Abstract
Nicotine addiction is a severe public health problem. The aim of this study was to investigate the alterations in key neurotransmissions after 60 days of withdrawal from seven weeks of intermittent cigarette smoke, e-cigarette vapours, or an e-cigarette vehicle. In the nicotine withdrawal groups, increased depressive and anxiety/obsessive–compulsive-like behaviours were demonstrated in the tail suspension, sucrose preference and marble burying tests. Cognitive impairments were detected in the spatial object recognition test. A significant increase in Corticotropin-releasing factor (Crf) and Crf1 mRNA levels was observed, specifically after cigarette withdrawal in the caudate-putamen nucleus (CPu). The nociceptin precursor levels were reduced by cigarette (80%) and e-cigarette (50%) withdrawal in the CPu. The delta opioid receptor showed a significant reduction in the hippocampus driven by the exposure to an e-cigarette solubilisation vehicle, while the mRNA levels doubled in the CPu of mice that had been exposed to e-cigarettes. Withdrawal after exposure to e-cigarette vapour induced a 35% Bdnf mRNA decrease in the hippocampus, whereas Bdnf was augmented by 118% by cigarette withdrawal in the CPu. This study shows that long-term withdrawal-induced affective and cognitive symptoms associated to lasting molecular alterations in peptidergic signalling may determine the impaired neuroplasticity in the hippocampal and striatal circuitry.
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A Rationale for Hypoxic and Chemical Conditioning in Huntington's Disease. Int J Mol Sci 2021; 22:ijms22020582. [PMID: 33430140 PMCID: PMC7826574 DOI: 10.3390/ijms22020582] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/23/2020] [Accepted: 01/05/2021] [Indexed: 12/17/2022] Open
Abstract
Neurodegenerative diseases are characterized by adverse cellular environments and pathological alterations causing neurodegeneration in distinct brain regions. This development is triggered or facilitated by conditions such as hypoxia, ischemia or inflammation and is associated with disruptions of fundamental cellular functions, including metabolic and ion homeostasis. Targeting intracellular downstream consequences to specifically reverse these pathological changes proved difficult to translate to clinical settings. Here, we discuss the potential of more holistic approaches with the purpose to re-establish a healthy cellular environment and to promote cellular resilience. We review the involvement of important molecular pathways (e.g., the sphingosine, δ-opioid receptor or N-Methyl-D-aspartate (NMDA) receptor pathways) in neuroprotective hypoxic conditioning effects and how these pathways can be targeted for chemical conditioning. Despite the present scarcity of knowledge on the efficacy of such approaches in neurodegeneration, the specific characteristics of Huntington’s disease may make it particularly amenable for such conditioning techniques. Not only do classical features of neurodegenerative diseases like mitochondrial dysfunction, oxidative stress and inflammation support this assumption, but also specific Huntington’s disease characteristics: a relatively young age of neurodegeneration, molecular overlap of related pathologies with hypoxic adaptations and sensitivity to brain hypoxia. The aim of this review is to discuss several molecular pathways in relation to hypoxic adaptations that have potential as drug targets in neurodegenerative diseases. We will extract the relevance for Huntington’s disease from this knowledge base.
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Lopes de Faria JM, Duarte DA, Simó R, García-Ramirez M, Dátilo MN, Pasqualetto FC, Lopes de Faria JB. δ Opioid Receptor Agonism Preserves the Retinal Pigmented Epithelial Cell Tight Junctions and Ameliorates the Retinopathy in Experimental Diabetes. Invest Ophthalmol Vis Sci 2020; 60:3842-3853. [PMID: 31529081 DOI: 10.1167/iovs.19-26761] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Outer blood retinal barrier breakdown is a neglected feature of diabetic retinopathy (DR). We demonstrated that the agonism of the δ opioid receptor (DOR) by epicatechin preserves the tight junction proteins in ARPE-19 cells under diabetic conditions. Presently, we aimed to evaluate the possible role of the DOR on the maintenance of tight junction of RPE layer and on the early markers of experimental DR. Methods DR markers and external retinal tight junction proteins were evaluated in CL57B diabetic mice submitted to intravitreous injection of short hairpin RNA (shRNA)-DOR (108 transducing units [TU]/mL) treated or not with DOR agonist (0.05 g/animal/d of epicatechin in drinking water) for 16 weeks. The presence of DOR in human retina from postmortem eyes from diabetic and nondiabetic donors were also performed. Results DOR is present in RPE layer and in neuro retina. The treatment with DOR agonist prevented the upregulation of the early markers of retinopathy (glial fibrillary acidic protein, VEGF) and the downregulation of pigment epithelium-derived factor, occludin, claudin-1, and zonula occludens-1 tight junction expressions. The silencing of DOR in retina of diabetic mice partially abolished the protective effects of epicatechin. In human retina specimens, DOR is present throughout the retina, similarly in nondiabetic and diabetic donors. Conclusions This set of experiments strongly indicates that the DOR agonism preserves RPE tight junctions and reduces the early markers of retinopathy in model of diabetes. These novel findings designate DOR as a potential therapeutic tool to treat DR with preservation of the RPE tight junction proteins.
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Affiliation(s)
- Jacqueline M Lopes de Faria
- Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil
| | - Diego A Duarte
- Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil
| | - Rafael Simó
- Vall d'Hebron Research Institute (VHIR) and CIBERDEM, Barcelona, Spain
| | | | - Marcella N Dátilo
- Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil
| | - Francieli C Pasqualetto
- Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil
| | - José B Lopes de Faria
- Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil
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Prolonged DADLE exposure epigenetically promotes Bcl-2 expression and elicits neuroprotection in primary rat cortical neurons via the PI3K/Akt/NF-κB pathway. Acta Pharmacol Sin 2018; 39:1582-1589. [PMID: 29795362 DOI: 10.1038/aps.2018.7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/02/2018] [Indexed: 01/09/2023] Open
Abstract
Both in vivo and in vitro studies have shown the beneficial effects of the delta-opioid receptor (DOR) on neurodegeneration in hypoxia/ischemia. We previously reported that DOR stimulation with [(D-Ala2, D-Leu5) enkephalin] (DADLE), a potent DOR agonist, for both a short (minutes) and long (days) time has notable protective effects against sodium azide (NaN3)-induced cell injury in primary cultured rat cortical neurons. We further demonstrated that short-term DADLE stimulation increased neuronal survival through the PKC-mitochondrial ERK pathway. However, the mechanisms underlying long-term neuroprotection by DADLE remain unclear. Here, we showed that DOR stimulation with DADLE (0.1 μmol/L) for 2 d selectively activates the PI3K/Akt/NF-κB pathway in NaN3-treated neurons; this activation increased Bcl-2 expression, attenuated Cyto c release and promoted neuronal survival. Further investigation revealed that sustained DADLE stimulation increased Bcl-2 expression by enhancing NF-κB binding to the Bcl-2 promoter and upregulating the histone acetylation levels of the Bcl-2 promoter. Our results demonstrate that prolonged DADLE exposure epigenetically promotes Bcl-2 expression and elicits neuroprotective effects in the NaN3 model via the PI3K/Akt/NF-κB pathway.
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Burtscher J, Bean C, Zangrandi L, Kmiec I, Agostinho A, Scorrano L, Gnaiger E, Schwarzer C. Proenkephalin Derived Peptides Are Involved in the Modulation of Mitochondrial Respiratory Control During Epileptogenesis. Front Mol Neurosci 2018; 11:351. [PMID: 30319356 PMCID: PMC6167428 DOI: 10.3389/fnmol.2018.00351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 09/07/2018] [Indexed: 12/12/2022] Open
Abstract
Epilepsies are a group of common neurological diseases exerting a strong burden on patients and society, often lacking clear etiology and effective therapeutical strategies. Early intervention during the development of epilepsy (epileptogenesis) is of great medical interest, though hampered by poorly characterized epileptogenetic processes. Using the intrahippocampal kainic acid mouse model of temporal lobe epilepsy, we investigated the functional role of the endogenous opioid enkephalin during epileptogenesis. We addressed three sequential questions: (1) How does enkephalin affect seizure threshold and how is it regulated during epileptogenesis? (2) Does enkephalin influence detrimental effects during epileptogenesis? (3) How is enkephalin linked to mitochondrial function during epileptogenesis?. In contrast to other neuropeptides, the expression of enkephalin is not regulated in a seizure dependent manner. The pattern of regulation, and enkephalin's proconvulsive effects suggested it as a potential driving force in epileptogenesis. Surprisingly, enkephalin deficiency aggravated progressive granule cell dispersion in kainic acid induced epileptogenesis. Based on reported beneficial effects of enkephalin on mitochondrial function in hypoxic/ischemic states, we hypothesized that enkephalin may be involved in the adaptation of mitochondrial respiration during epileptogenesis. Using high-resolution respirometry, we observed dynamic improvement of hippocampal mitochondrial respiration after kainic acid-injections in wild-type, but not in enkephalin-deficient mice. Thus, wild-type mice displayed higher efficiency in the use of mitochondrial capacity as compared to enkephalin-deficient mice. Our data demonstrate a Janus-headed role of enkephalin in epileptogenesis. In naive mice, enkephalin facilitates seizures, but in subsequent stages it contributes to neuronal survival through improved mitochondrial respiration.
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Affiliation(s)
- Johannes Burtscher
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Camilla Bean
- Department of Biology, University of Padua, Padua, Italy.,Venetian Institute of Molecular Medicine, Padua, Italy
| | - Luca Zangrandi
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Iwona Kmiec
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Alexandra Agostinho
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Luca Scorrano
- Department of Biology, University of Padua, Padua, Italy.,Venetian Institute of Molecular Medicine, Padua, Italy
| | - Erich Gnaiger
- D. Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Medical University of Innsbruck, Innsbruck, Austria.,Oroboros Instruments, Innsbruck, Austria
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
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Burtscher J, Schwarzer C. The Opioid System in Temporal Lobe Epilepsy: Functional Role and Therapeutic Potential. Front Mol Neurosci 2017; 10:245. [PMID: 28824375 PMCID: PMC5545604 DOI: 10.3389/fnmol.2017.00245] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/24/2017] [Indexed: 12/13/2022] Open
Abstract
Temporal lobe epilepsy is considered to be one of the most common and severe forms of focal epilepsies. Patients often develop cognitive deficits and emotional blunting along the progression of the disease. The high incidence of resistance to antiepileptic drugs and a frequent lack of admissibility to surgery poses an unmet medical challenge. In the urgent quest of novel treatment strategies, neuropeptides are interesting candidates, however, their therapeutic potential has not yet been exploited. This review focuses on the functional role of the endogenous opioid system with respect to temporal lobe epilepsy, specifically in the hippocampus. The role of dynorphins and kappa opioid receptors (KOPr) as modulators of neuronal excitability is well understood: both the reduced release of glutamate as well of postsynaptic hyperpolarization were shown in glutamatergic neurons. In line with this, low levels of dynorphin in humans and mice increase the risk of epilepsy development. The role of enkephalins is not understood so well. On one hand, some agonists of the delta opioid receptors (DOPr) display pro-convulsant properties probably through inhibition of GABAergic interneurons. On the other hand, enkephalins play a neuro-protective role under hypoxic or anoxic conditions, most probably through positive effects on mitochondrial function. Despite the supposed absence of endorphins in the hippocampus, exogenous activation of the mu opioid receptors (MOPr) induces pro-convulsant effects. Recently-expanded knowledge of the complex ways opioid receptors ligands elicit their effects (including biased agonism, mixed binding, and opioid receptor heteromers), opens up exciting new therapeutic potentials with regards to seizures and epilepsy. Potential adverse side effects of KOPr agonists may be minimized through functional selectivity. Preclinical data suggest a high potential of such compounds to control seizures, with a strong predictive validity toward human patients. The discovery of DOPr-agonists without proconvulsant potential stimulates the research on the therapeutic use of neuroprotective potential of the enkephalin/DOPr system.
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Affiliation(s)
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of InnsbruckInnsbruck, Austria
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Shrivastava P, Cabrera MA, Chastain LG, Boyadjieva NI, Jabbar S, Franklin T, Sarkar DK. Mu-opioid receptor and delta-opioid receptor differentially regulate microglial inflammatory response to control proopiomelanocortin neuronal apoptosis in the hypothalamus: effects of neonatal alcohol. J Neuroinflammation 2017; 14:83. [PMID: 28407740 PMCID: PMC5391607 DOI: 10.1186/s12974-017-0844-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 03/19/2017] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Opioid receptors are known to control neurotransmission of various peptidergic neurons, but their potential role in regulation of microglia and neuronal cell communications is unknown. We investigated the role of mu-opioid receptors (MOR) and delta-opioid receptors (DOR) on microglia in the regulation of apoptosis in proopiomelanocortin (POMC) neurons induced by neonatal ethanol in the hypothalamus. METHODS Neonatal rat pups were fed a milk formula containing ethanol or control diets between postnatal days 2-6. Some of the alcohol-fed rats additionally received pretreatment of a microglia activation blocker minocycline. Two hours after the last feeding, some of the pups were sacrificed and processed for histochemical detection of microglial cell functions or confocal microscopy for detection of cellular physical interaction or used for gene and protein expression analysis. The rest of the pups were dissected for microglia separation by differential gradient centrifugation and characterization by measuring production of various activation markers and cytokines. In addition, primary cultures of microglial cells were prepared using hypothalamic tissues of neonatal rats and used for determination of cytokine production/secretion and apoptotic activity of neurons. RESULTS In the hypothalamus, neonatal alcohol feeding elevated cytokine receptor levels, increased the number of microglial cells with amoeboid-type circularity, enhanced POMC and microglial cell physical interaction, and decreased POMC cell numbers. Minocycline reversed these cellular effects of alcohol. Alcohol feeding also increased levels of microglia MOR protein and pro-inflammatory signaling molecules in the hypothalamus, and MOR receptor antagonist naltrexone prevented these effects of alcohol. In primary cultures of hypothalamic microglia, both MOR agonist [D-Ala 2, N-MePhe 4, Gly-ol]-enkephalin (DAMGO) and ethanol increased microglial cellular levels and secretion of pro-inflammatory cell signaling proteins. However, a DOR agonist [D-Pen2,5]enkephalin (DPDPE) increased microglial secretion of anti-inflammatory cytokines and suppressed ethanol's ability to increase microglial production of inflammatory signaling proteins and secretion of pro-inflammatory cytokines. In addition, MOR-activated inflammation promoted while DOR-suppressed inflammation inhibited the apoptotic effect of ethanol on POMC neurons. CONCLUSIONS These results suggest that ethanol's neurotoxic action on POMC neurons results from MOR-activated neuroinflammatory signaling. Additionally, these results identify a protective effect of a DOR agonist against the pro-inflammatory and neurotoxic action of ethanol.
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Affiliation(s)
- Pallavi Shrivastava
- The Endocrine Program, Department of Animal Sciences, Rutgers, The State University of New Jersey, 67 Poultry Lane, New Brunswick, NJ, 08901, USA
| | - Miguel A Cabrera
- The Endocrine Program, Department of Animal Sciences, Rutgers, The State University of New Jersey, 67 Poultry Lane, New Brunswick, NJ, 08901, USA
| | - Lucy G Chastain
- The Endocrine Program, Department of Animal Sciences, Rutgers, The State University of New Jersey, 67 Poultry Lane, New Brunswick, NJ, 08901, USA
| | - Nadka I Boyadjieva
- The Endocrine Program, Department of Animal Sciences, Rutgers, The State University of New Jersey, 67 Poultry Lane, New Brunswick, NJ, 08901, USA
| | - Shaima Jabbar
- The Endocrine Program, Department of Animal Sciences, Rutgers, The State University of New Jersey, 67 Poultry Lane, New Brunswick, NJ, 08901, USA
| | - Tina Franklin
- The Endocrine Program, Department of Animal Sciences, Rutgers, The State University of New Jersey, 67 Poultry Lane, New Brunswick, NJ, 08901, USA
| | - Dipak K Sarkar
- The Endocrine Program, Department of Animal Sciences, Rutgers, The State University of New Jersey, 67 Poultry Lane, New Brunswick, NJ, 08901, USA.
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Wei YC, Zhang B, Li X, Liu XM, Zhang J, Lei B, Li B, Zhai R, Chen Q, Li Y. Upregulation and activation of δ‑opioid receptors promotes the progression of human breast cancer. Oncol Rep 2016; 36:2579-2586. [PMID: 27665747 DOI: 10.3892/or.2016.5109] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 03/26/2016] [Indexed: 11/05/2022] Open
Abstract
δ‑opioid receptor (DOR) belongs to the family of G protein‑coupled receptors (GPCRs). Numerous studies have shown that DOR is widely distributed in human peripheral tissues and is closely related to the development and progression of certain malignant tumours. However, there is controversy in the literature regarding whether DOR has an impact on the development and progression of human breast cancer. The present study comprehensively elaborates on the biological functions of DOR by determining the distribution of DOR expression in breast cancer tissues and cells and by further verifying the effects of DOR on breast cancer progression. DOR was found to be highly expressed in human breast cancer tissues and cells. In addition, the high expression level of DOR positively correlated with tumour grade and clinical stage and negatively correlated with breast cancer metastasis and prognosis. Upregulating and activating DOR promoted the proliferation of human breast cancer cells in a concentration‑dependent manner within a specific concentration range, whereas downregulating or inhibiting DOR activation significantly suppressed cell proliferation. The majority of tumour cells were arrested in G1 phase, and some cells exhibited apoptosis. DOR upregulation and activation induced protein kinase C (PKC) activation, resulting in increased phosphorylation levels of extracellular signal‑regulated kinases (ERKs). After inhibition of the PKC/ERK signalling pathway, the effects of DOR on breast cancer were significantly attenuated in vivo and in vitro. In summary, DOR is highly expressed in breast cancer and is closely related to its progression. These results suggest that DOR may serve as a potential biomarker for the early diagnosis of breast cancer and may be a viable molecular target for therapeutic intervention.
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Affiliation(s)
- Yang-Chao Wei
- Department of Medical Oncology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541001, P.R. China
| | - Bin Zhang
- Department of Breast and Thyroid Surgery, The First Hospital of Jining, Jining, Shandong 272011, P.R. China
| | - Xuan Li
- Department of Hepatobiliary Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541001, P.R. China
| | - Xiao-Meng Liu
- Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong University, Jinan, Shandong 250017, P.R. China
| | - Jing Zhang
- Department of Hepatobiliary Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541001, P.R. China
| | - Biao Lei
- Department of Hepatobiliary Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541001, P.R. China
| | - Bo Li
- Department of Hepatobiliary Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541001, P.R. China
| | - Run Zhai
- Department of Hepatobiliary Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541001, P.R. China
| | - Qian Chen
- Department of Hepatobiliary Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541001, P.R. China
| | - Yang Li
- Department of Medical Oncology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541001, P.R. China
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Yang DJ, Lee KS, Ko CM, Moh SH, Song J, Hur LC, Cheon YW, Yang SH, Choi YH, Kim KW. Leucine-enkephalin promotes wound repair through the regulation of hemidesmosome dynamics and matrix metalloprotease. Peptides 2016; 76:57-64. [PMID: 26763532 DOI: 10.1016/j.peptides.2015.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 12/03/2015] [Accepted: 12/29/2015] [Indexed: 11/17/2022]
Abstract
The skin responds to environmental stressors by coordinated actions of neuropeptides and their receptors. An endogenous peptide for δ-opioid receptor (DOPr), Leu-enkephalin (L-ENK), is expressed in the skin and its expression is altered in pathological conditions. Although the importance of DOPr is rapidly gaining recognition, the molecular mechanisms underlying its effects on wound healing are largely undefined. We show here that L-ENK induced activation of Erk, P90(RSK), and Elk-1 and promoted the disruption of hemidesmosomes and the expression of matrix metalloprotease (MMP)-2 and MMP-9, important processes for wound healing. Treatment with Erk inhibitor blocked activation of P90(RSK) and Elk-1 and significantly blunted wound repair. Therefore, our results suggest that activation of Erk and its downstream effectors, P90(RSK) and Elk-1, are critical for DOPr-mediated skin homeostasis.
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Affiliation(s)
- Dong Joo Yang
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea; Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea
| | - Kyung Suk Lee
- Department of Plastic and Reconstructive Surgery, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju 52828, Republic of Korea
| | - Chang Mann Ko
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea
| | - Sang Hyun Moh
- Anti-aging Research Institute of BIO-FD&C Co. Ltd., Incheon 21990, Republic of Korea
| | - Jihyeok Song
- Anti-aging Research Institute of BIO-FD&C Co. Ltd., Incheon 21990, Republic of Korea
| | - Lucia C Hur
- Derma-Lucia Skinceuticals LLC, 7500 Escala Drive, Austin, TX 78735, USA
| | - Young Woo Cheon
- Department of Plastic and Reconstructive Surgery, Gachon University Gil Medical Center, Gachon University, School of Medicine, 1198 Guwol-Dong, Namdong-Gu, Incheon 21565, Republic of Korea
| | - Seung Ho Yang
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea
| | - Yun-Hee Choi
- Anti-aging Research Institute of BIO-FD&C Co. Ltd., Incheon 21990, Republic of Korea.
| | - Ki Woo Kim
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea; Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea.
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15
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He X, Sandhu HK, Yang Y, Hua F, Belser N, Kim DH, Xia Y. Neuroprotection against hypoxia/ischemia: δ-opioid receptor-mediated cellular/molecular events. Cell Mol Life Sci 2013; 70:2291-303. [PMID: 23014992 PMCID: PMC11113157 DOI: 10.1007/s00018-012-1167-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 09/08/2012] [Accepted: 09/10/2012] [Indexed: 12/24/2022]
Abstract
Hypoxic/ischemic injury remains the most dreaded cause of neurological disability and mortality. Despite the humbling experiences due to lack of promising therapy, our understanding of the complex cascades underlying the neuronal insult has led to advances in basic science research. One of the most noteworthy has been the effect of opioid receptors, especially the delta-opioid receptor (DOR), on hypoxic/ischemic neurons. Our recent studies, and those of others worldwide, present strong evidence that sheds light on DOR-mediated neuroprotection in the brain, especially in the cortex. The mechanisms of DOR neuroprotection are broadly categorized as: (1) stabilization of the ionic homeostasis, (2) inhibition of excitatory transmitter release, (3) attenuation of disrupted neuronal transmission, (4) increase in antioxidant capacity, (5) regulation of intracellular pathways-inhibition of apoptotic signals and activation of pro-survival signaling, (6) regulation of specific gene and protein expression, and (7) up-regulation of endogenous opioid release and/or DOR expression. Depending upon the severity and duration of hypoxic/ischemic insult, the release of endogenous opioids and DOR expression are regulated in response to the stress, and DOR signaling acts at multiple levels to confer neuronal tolerance to harmful insult. The phenomenon of DOR neuroprotection offers a potential clue for a promising target that may have significant clinical implications in our quest for neurotherapeutics.
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Affiliation(s)
- Xiaozhou He
- The Third Clinical College of Suzhou University, Changzhou, Jiangsu China
| | - Harleen K. Sandhu
- The Vivian L Smith Department of Neurosurgery, The University of Texas Medical School at Houston, Houston, 77030 TX USA
| | - Yilin Yang
- The Third Clinical College of Suzhou University, Changzhou, Jiangsu China
| | - Fei Hua
- The Third Clinical College of Suzhou University, Changzhou, Jiangsu China
| | - Nathalee Belser
- The Vivian L Smith Department of Neurosurgery, The University of Texas Medical School at Houston, Houston, 77030 TX USA
| | - Dong H. Kim
- The Vivian L Smith Department of Neurosurgery, The University of Texas Medical School at Houston, Houston, 77030 TX USA
| | - Ying Xia
- The Vivian L Smith Department of Neurosurgery, The University of Texas Medical School at Houston, Houston, 77030 TX USA
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Chu Sin Chung P, Kieffer BL. Delta opioid receptors in brain function and diseases. Pharmacol Ther 2013; 140:112-20. [PMID: 23764370 DOI: 10.1016/j.pharmthera.2013.06.003] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 05/15/2013] [Indexed: 01/02/2023]
Abstract
Evidence that the delta opioid receptor (DOR) is an attractive target for the treatment of brain disorders has strengthened in recent years. This receptor is broadly expressed in the brain, binds endogenous opioid peptides, and shows as functional profile highly distinct from those of mu and kappa opioid receptors. Our knowledge of DOR function has enormously progressed from in vivo studies using pharmacological tools and genetic approaches. The important role of this receptor in reducing chronic pain has been extensively overviewed; therefore this review focuses on facets of delta receptor activity relevant to psychiatric and other neurological disorders. Beneficial effects of DOR agonists are now well established in the context of emotional responses and mood disorders. DOR activation also regulates drug reward, inhibitory controls and learning processes, but whether delta compounds may represent useful drugs in the treatment of drug abuse remains open. Epileptogenic and locomotor-stimulating effects of delta agonists appear drug-dependent, and the possibility of biased agonism at DOR for these effects is worthwhile further investigations to increase benefit/risk ratio of delta therapies. Neuroprotective effects of DOR activity represent a forthcoming research area. Future developments in DOR research will benefit from in-depth investigations of DOR function at cellular and circuit levels.
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Affiliation(s)
- Paul Chu Sin Chung
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR7104 CNRS/Université de Strasbourg, U964 INSERM, Illkirch, France
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Abstract
This paper is the thirty-fourth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2011 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
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18
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Pang W, Lu H, Hu YD, Yang HP, Leng X, Jiang YG. Depletion of intracellular zinc induced apoptosis in cultured hippocampal neurons through Raf/MEK/ERK pathways. Nutr Neurosci 2012; 15:18-24. [PMID: 22305649 DOI: 10.1179/1476830511y.0000000031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
An experiment was performed to observe the changes in Raf-1 kinase/mitogen-activated protein kinase ERK (MEK)/extracellular signal-regulated kinase (ERK) signaling pathways in cultured hippocampal neurons and its correlation with neurons apoptosis induced by intracellular zinc depletion. Cultured hippocampal neurons were exposed to a cell membrane-permeant zinc chelator TPEN (2 µM), and to TPEN plus zinc sulfate (5 µM) for 24 h. Cultures were then processed to detect neuronal viability by the methyl thiazolyl tetrazolium assay, while apoptosis rate was simultaneously observed by the flow cytometric analysis. Caspase-3, Raf-1, pMEK, pERK1/2, and pCREB protein levels were examined by Western blot assays. The viability in TPEN-incubated neurons was notably decreased, apoptosis rate and expression of caspase-3 significantly increased compared to untreated controls. The significant down-regulation of Raf/MEK/ERK signaling pathway and expression of pCREB were decreased in TPEN-treated neurons. Co-addition of zinc almost completely reversed TPEN-induced alterations described. The results demonstrated zinc-modulated apoptosis and the expression of Raf/MEK/ERK at the protein level in hippocampal neurons. It is possible that zinc depletion-induced apoptosis in cultured hippocampal neurons may be relevant to the changes of Raf/MEK/ERK signaling pathway.
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Affiliation(s)
- Wei Pang
- Department of Nutrition, Institute of Hygiene & Environmental Medicine, Academy of Military Medical Science, Tianjin, China
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