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Chen Y, Zhang H, Jiang L, Cai W, Kuang J, Geng Y, Xu H, Li Y, Yang L, Cai Y, Wang X, Xiao J, Ni W, Zhou K. DADLE promotes motor function recovery by inhibiting cytosolic phospholipase A 2 mediated lysosomal membrane permeabilization after spinal cord injury. Br J Pharmacol 2024; 181:712-734. [PMID: 37766498 DOI: 10.1111/bph.16255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 09/15/2023] [Accepted: 09/21/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND AND PURPOSE Autophagy is a protective factor for controlling neuronal damage, while necroptosis promotes neuroinflammation after spinal cord injury (SCI). DADLE (D-Ala2 , D-Leu5 ]-enkephalin) is a selective agonist for delta (δ) opioid receptor and has been identified as a promising drug for neuroprotection. The aim of this study was to investigate the mechanism/s by which DADLE causes locomotor recovery following SCI. EXPERIMENTAL APPROACH Spinal cord contusion model was used and DADLE was given by i.p. (16 mg·kg-1 ) in mice for following experiments. Motor function was assessed by footprint and Basso mouse scale (BMS) score analysis. Western blotting used to evaluate related protein expression. Immunofluorescence showed the protein expression in each cell and its distribution. Network pharmacology analysis was used to find the related signalling pathways. KEY RESULTS DADLE promoted functional recovery after SCI. In SCI model of mice, DADLE significantly increased autophagic flux and inhibited necroptosis. Concurrently, DADLE restored autophagic flux by decreasing lysosomal membrane permeabilization (LMP). Additionally, chloroquine administration reversed the protective effect of DADLE to inhibit necroptosis. Further analysis showed that DADLE decreased phosphorylated cPLA2 , overexpression of cPLA2 partially reversed DADLE inhibitory effect on LMP and necroptosis, as well as the promotion autophagy. Finally, AMPK/SIRT1/p38 pathway regulating cPLA2 is involved in the action DADLE on SCI and naltrindole inhibited DADLE action on δ receptor and on AMPK signalling pathway. CONCLUSION AND IMPLICATION DADLE causes its neuroprotective effects on SCI by promoting autophagic flux and inhibiting necroptosis by decreasing LMP via activating δ receptor/AMPK/SIRT1/p38/cPLA2 pathway.
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Affiliation(s)
- Yituo Chen
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, China
- The Second Clinical Medical College of Wenzhou Medical University, Wenzhou, China
| | - Haojie Zhang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, China
- The Second Clinical Medical College of Wenzhou Medical University, Wenzhou, China
| | - Liting Jiang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, China
- The Second Clinical Medical College of Wenzhou Medical University, Wenzhou, China
| | - Wanta Cai
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, China
- The Second Clinical Medical College of Wenzhou Medical University, Wenzhou, China
| | - Jiaxuan Kuang
- Cixi Biomedical Research Institute, Wenzhou Medical University, Ningbo, China
| | - Yibo Geng
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, China
- The Second Clinical Medical College of Wenzhou Medical University, Wenzhou, China
| | - Hui Xu
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, China
- The Second Clinical Medical College of Wenzhou Medical University, Wenzhou, China
| | - Yao Li
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, China
- The Second Clinical Medical College of Wenzhou Medical University, Wenzhou, China
| | - Liangliang Yang
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Yuepiao Cai
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Xiangyang Wang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, China
- The Second Clinical Medical College of Wenzhou Medical University, Wenzhou, China
| | - Jian Xiao
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Wenfei Ni
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, China
- The Second Clinical Medical College of Wenzhou Medical University, Wenzhou, China
| | - Kailiang Zhou
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
- Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, China
- The Second Clinical Medical College of Wenzhou Medical University, Wenzhou, China
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Sudakov S, Bogdanova N. Involvement of Peripheral Opioid Receptors in the Realization of Food Motivation Into Eating Behavior. Front Behav Neurosci 2021; 14:600920. [PMID: 33510624 PMCID: PMC7835398 DOI: 10.3389/fnbeh.2020.600920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/09/2020] [Indexed: 11/21/2022] Open
Abstract
The involvement of peripheral opioid receptors in the mechanisms of eating behavior is still unclear. The aim of this work was to study the role of peripheral, predominantly gastric mu and delta opioid receptors in the realization of food motivation in conditions of different energy costs for eating behavior. Experiments were performed under a between-sessions progressive ratio schedule of reinforcement in food-deprived rats. The level of food motivation was calculated using a self-developed method. Food intake, motor activity, and metabolic rate were recorded in fed and hungry animals. Results showed that intragastric administration of the mu opioid receptor agonist DAMGO led to an increase in the level of food motivation in the light variant of operant feeding behaviors. Food consumption did not change. At high costs for feeding behavior, the administration of DAMGO did not alter food motivation; however, food consumption and motor activity were reduced. Intragastric administration of the delta opioid receptor agonist DADLE did not lead to changes in the level of food motivation and physical activity, but inhibition of feeding behavior was observed in all reinforcement schedules. Three regulatory pathways of eating behavior in difficult food conditions by peripheral, predominantly gastric opioid receptors are hypothesized: environmental-inhibitory afferentations and suppression of the realization of food motivation into behavior; homeostatic-inhibitory action on food motivation; and rewarding-suppression of the anticipatory reinforcement.
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Affiliation(s)
- Sergey Sudakov
- Laboratory of Physiology of Reinforcement, P.K. Anokhin Research Institute of Normal Physiology, Moscow, Russia
| | - Natalia Bogdanova
- Laboratory of Physiology of Reinforcement, P.K. Anokhin Research Institute of Normal Physiology, Moscow, Russia
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Cassell RJ, Sharma KK, Su H, Cummins BR, Cui H, Mores KL, Blaine AT, Altman RA, van Rijn RM. The Meta-Position of Phe 4 in Leu-Enkephalin Regulates Potency, Selectivity, Functional Activity, and Signaling Bias at the Delta and Mu Opioid Receptors. Molecules 2019; 24:molecules24244542. [PMID: 31842282 PMCID: PMC6943441 DOI: 10.3390/molecules24244542] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 12/08/2019] [Accepted: 12/10/2019] [Indexed: 01/10/2023] Open
Abstract
As tool compounds to study cardiac ischemia, the endogenous δ-opioid receptors (δOR) agonist Leu5-enkephalin and the more metabolically stable synthetic peptide (d-Ala2, d-Leu5)-enkephalin are frequently employed. However, both peptides have similar pharmacological profiles that restrict detailed investigation of the cellular mechanism of the δOR’s protective role during ischemic events. Thus, a need remains for δOR peptides with improved selectivity and unique signaling properties for investigating the specific roles for δOR signaling in cardiac ischemia. To this end, we explored substitution at the Phe4 position of Leu5-enkephalin for its ability to modulate receptor function and selectivity. Peptides were assessed for their affinity to bind to δORs and µ-opioid receptors (µORs) and potency to inhibit cAMP signaling and to recruit β-arrestin 2. Additionally, peptide stability was measured in rat plasma. Substitution of the meta-position of Phe4 of Leu5-enkephalin provided high-affinity ligands with varying levels of selectivity and bias at both the δOR and µOR and improved peptide stability, while substitution with picoline derivatives produced lower-affinity ligands with G protein biases at both receptors. Overall, these favorable substitutions at the meta-position of Phe4 may be combined with other modifications to Leu5-enkephalin to deliver improved agonists with finely tuned potency, selectivity, bias and drug-like properties.
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MESH Headings
- Animals
- CHO Cells
- Cricetulus
- Enkephalin, Leucine/genetics
- Enkephalin, Leucine/pharmacology
- Humans
- Phenylalanine
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Signal Transduction/drug effects
- Signal Transduction/genetics
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Affiliation(s)
- Robert J. Cassell
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (R.J.C.); (H.S.); (K.L.M.); (A.T.B.)
| | - Krishna K. Sharma
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, KS 66045, USA;
| | - Hongyu Su
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (R.J.C.); (H.S.); (K.L.M.); (A.T.B.)
| | | | - Haoyue Cui
- College of Wuya, Shenyang Pharmaceutical University, Shenyang 110016, China;
| | - Kendall L. Mores
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (R.J.C.); (H.S.); (K.L.M.); (A.T.B.)
| | - Arryn T. Blaine
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (R.J.C.); (H.S.); (K.L.M.); (A.T.B.)
| | - Ryan A. Altman
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, KS 66045, USA;
- Correspondence: (R.A.A.); (R.M.v.R.)
| | - Richard M. van Rijn
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (R.J.C.); (H.S.); (K.L.M.); (A.T.B.)
- Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
- Correspondence: (R.A.A.); (R.M.v.R.)
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Wang S, Cao X, Duan Y, Zhang G. Delta Opioid Peptide [d-Ala2, d-Leu5] Enkephalin ( DADLE) Exerts a Cytoprotective Effect in Astrocytes Exposed to Oxygen-Glucose Deprivation by Inducing Autophagy. Cell Transplant 2019; 28:775-782. [PMID: 30666890 PMCID: PMC6686437 DOI: 10.1177/0963689719825619] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Astrocytes protection and functional regulation are important strategies to protect against neuronal damage caused by ischemia. Activation of the delta opioid receptor (DOR) could reduce astrocytes damage, although the mechanism remains unclear. The present study aimed to test the effect of DOR activation on autophagy in astrocytes exposed to oxygen-glucose deprivation (OGD), and to further investigate whether this effect has a protective effect on astrocytes. Primary cultured rat cortical astrocytes were treated with various doses of [d-Ala2, d-Leu5]-Enkephalin (DADLE, a selective DOR agonist) followed by 6 h OGD. Cell viability was evaluated by CCK-8 assay and lactate dehydrogenase release. Autophagic vacuole was analyzed with LC3 immunofluorescent staining. The levels of autophagy and apoptosis-related proteins were analyzed by western blot. Results demonstrated that treatment with 10 nM DADLE was sufficient to increase cell viability and induced autophagy in astrocytes. The DADLE-induced autophagy displayed a cytoprotective effect on astrocytes. Inhibition of autophagy by 3-methyladenine (3-MA, an autophagy inhibitor) reversed the protective effect of DADLE. Naltrindole (a DOR antagonist) only partially antagonized the role of DADLE, which indicated that DADLE might have a cytoprotective mechanism independent of DOR. Further results showed that DADLE significantly enhanced the level of Bcl-2 protein and reduced the level of Bax protein in astrocytes exposed to OGD. Our results suggest a novel mechanism in which DADLE induces autophagy in astrocytes and exerts cytoprotective effects by inhibiting apoptosis.
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Affiliation(s)
- Shuyan Wang
- 1 Department of Anesthesiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, China
| | - Xiaoqiong Cao
- 1 Department of Anesthesiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, China
| | - Yale Duan
- 2 Key Laboratory of Brain Functional Genomics, Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics, East China Normal University, China
| | - Guangming Zhang
- 1 Department of Anesthesiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, China
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Zhu M, Liu M, Guo QL, Zhu CQ, Guo JC. 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; 39:1582-9. [PMID: 29795362 DOI: 10.1038/aps.2018.7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Fu D, Liu H, Li S, Chen L, Yao J. Antioxidative and Antiapoptotic Effects of Delta-Opioid Peptide [D-Ala 2, D-Leu 5] Enkephalin on Spinal Cord Ischemia-Reperfusion Injury in Rabbits. Front Neurosci 2017; 11:603. [PMID: 29163008 PMCID: PMC5671641 DOI: 10.3389/fnins.2017.00603] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 10/16/2017] [Indexed: 01/09/2023] Open
Abstract
Background: In our previous study, we found that regional administration of delta-opioid peptide [D-Ala2, D-Leu5] enkephalin (DADLE) could provide dose-dependent protection on spinal cord ischemia-reperfusion (I/R) injury in rabbits. However, the relative protective molecular mechanisms underlying this neuroprotection remain unclear. The purpose of this study was to investigate whether DADLE provided the protection in spinal cord I/R injury through its antioxidant property by decreasing malondialdehyde (MDA) and nitric oxide (NO) levels and increasing glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels and through its antiapoptotic capacity by inhibiting caspase-3 and p53 expression. Methods: The rabbits were divided into three groups. The animals in Group NS and Group DADLE were administered with normal saline (NS) or DADLE via aorta during 30 min of ischemia respectively, while the one in Group Sham received no intervention. During the period of reperfusion, the rabbit's blood samples were collected for enzyme-linked immunoabsorbent assay (ELISA) examinations of MDA, NO, GSH-Px and SOD. At 48 h after reperfusion, the lumbar spinal cords were harvested for immunohistochemical, real-time polymerase chain reaction (PCR) and western blot studies to detect the caspase-3 and p53 expressions. Results: The activities of serum MDA and NO showed significant reductions in the DADLE group as compared with the control group. By contrast, the levels of serum GSH-Px and SOD were significantly higher in the DADLE group than those in the NS group. In addition, caspase-3 and p53 expression were significantly increased in the NS group, while DADLE mitigated these changes. Conclusions: The protective effects of DADLE at the dosage of 0.05 mg/kg may be related to its antioxidant and antiapoptosis properties in the rabbit model of spinal cord I/R injury.
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Affiliation(s)
- Danyun Fu
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haitong Liu
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shitong Li
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lianhua Chen
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Junyan Yao
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Zhao P, Kuai J, Gao J, Sun L, Wang Y, Yao L. Delta opioid receptor agonist attenuates lipopolysaccharide-induced myocardial injury by regulating autophagy. Biochem Biophys Res Commun 2017; 492:140-6. [PMID: 28647372 DOI: 10.1016/j.bbrc.2017.06.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Previous studies have described the protective effects of DADLE on myocardial injury in sepsis. Recently, autophagy has been shown to be an innate defense mechanism in sepsis-related myocardial injury. However, whether DADLE has an pro-autophagic effect is yet to be elucidated. The present study aimed to investigate the effect of DADLE on the regulation of autophagy during sepsis. METHODS Male mice were subjected to LPS or vehicle intraperitoneal injection. After LPS injection, mice received either DADLE, Naltrindole or vehicle. ELISA and JC-1 were used to evaluate the level cTnI and Mitochondrial membrane potential. Cardiac ultrastructural and autophagosomes were visualized by transmission electron microscopy. The relative protein levels were analyzed by Western blot. RESULTS The results showed that treatment with DADLE both immediately or 4 h after LPS intraperitoneal injection could improve the survival rate of mice with endotoxemic. DADLE could ease myocardium ultrastructure injury induced by LPS, this cardioprotective effect was also seen in increased MMP levels, and decreased cTnI levels. Through observation of transmission electron microscopy and Western blot we have discovered that the amount of autophagosome and the expression of autophagy related protein LC3II, Beclin1 were significantly increased with DADLE treatment. DADLE promoted LPS-induced autophagosome maturation as indicated by the increased LAMP-1 protein level and decreased SQSTM1/p62 protein level. The selective δ-opioid receptor antagonist Naltrindole play an opposite effects. CONCLUSIONS DADLE could improve the survival and protect myocardial dysfunction in mice with LPS-induced endotoxemia. This effect was related to the increase of autophagy.
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Grant Liska M, Crowley MG, Lippert T, Corey S, Borlongan CV. Delta Opioid Receptor and Peptide: A Dynamic Therapy for Stroke and Other Neurological Disorders. Handb Exp Pharmacol 2017; 247:277-299. [PMID: 28315071 DOI: 10.1007/164_2017_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Research of the opioid system and its composite receptors and ligands has revealed its promise as a potential therapy for neurodegenerative diseases such as stroke and Parkinson's Disease. In particular, delta opioid receptors (DORs) have been elucidated as a therapeutically distinguished subset of opioid receptors and a compelling target for novel intervention techniques. Research is progressively shedding light on the underlying mechanism of DORs and has revealed two mechanisms of DOR neuroprotection; DORs function to maintain ionic homeostasis and also to trigger endogenous neuroprotective pathways. Delta opioid agonists such as (D-Ala2, D-Leu5) enkephalin (DADLE) have been shown to promote neuronal survival and decrease apoptosis, resulting in a substantial amount of research for its application as a neurological therapeutic. Most notably, DADLE has demonstrated significant potential to reduce cell death following ischemic events. Current research is working to reveal the complex mechanisms of DADLE's neuroprotective properties. Ultimately, our knowledge of the DOR receptors and agonists has made the opioid system a promising target for therapeutic intervention in many neurological disorders.
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Affiliation(s)
- M Grant Liska
- Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, Tampa, FL, 33612, USA
| | - Marci G Crowley
- Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, Tampa, FL, 33612, USA
| | - Trenton Lippert
- Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, Tampa, FL, 33612, USA
| | - Sydney Corey
- Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, Tampa, FL, 33612, USA
| | - Cesar V Borlongan
- Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, Tampa, FL, 33612, USA.
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Tian J, Gu Y, Sun K, Wang B, Chen J, Wang X, Su D. [D-Ala2, D-Leu5] encephalin ( DADLE) reversibly inhibits cellular transcription in neurons without causing cell injury. Brain Res 2014; 1565:1-7. [PMID: 24735650 DOI: 10.1016/j.brainres.2014.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 04/05/2014] [Accepted: 04/07/2014] [Indexed: 01/01/2023]
Abstract
[d-Ala(2)-d-Leu(5)]-Enkephalin (DADLE) has shown promising results in protecting neurons from damages. However, the mechanism for this protection is still under investigation. The current study was carried out to test the hypothesis that DADLE may regulate cellular transcription in neurons. SH-SY5Y cells and primary cortical neurons were treated with various doses of DADLE for 24-72h. Results demonstrated that DADLE, at all doses and time points examined, significantly inhibited cellular transcription in both cells without causing cell injury. Following recovery for 72h without DADLE in primary neurons, the transcriptional activity fully resumed. Delta opioid receptor (DOR) is not involved in this process, as Naltrindole could not abolish DADLE׳s transcriptional inhibitory effects. Further studies in primary cortical neurons show that DADLE significantly inhibited phosphorylation of Ser2 and Ser5 of the C-terminal domain (CTD) of RNA polymerase II. These data indicate that DADLE is able to decrease cellular transcription through inhibiting phosphorylation of RNA polymerase II in neurons, which may provide mechanistic insight into its reported neuroprotective effects, and suggests that it warrants further exploration as a potential therapeutic strategy for neuroprotection.
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Affiliation(s)
- Jie Tian
- Department of Anesthesiology, Ren Ji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian road, Shanghai 200127, China
| | - Yang Gu
- Department of Anesthesiology, Ren Ji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian road, Shanghai 200127, China
| | - Ke Sun
- Department of Anesthesiology, Ren Ji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian road, Shanghai 200127, China
| | - Beilei Wang
- Department of Anesthesiology, Ren Ji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian road, Shanghai 200127, China
| | - Jie Chen
- Department of Anesthesiology, Ren Ji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian road, Shanghai 200127, China
| | - Xiangrui Wang
- Department of Anesthesiology, Ren Ji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian road, Shanghai 200127, China.
| | - Diansan Su
- Department of Anesthesiology, Ren Ji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian road, Shanghai 200127, China.
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Prokai-Tatrai K, Kim HS, Prokai L. The utility of oligopeptidase in brain-targeting delivery of an enkephalin analogue by prodrug design. Open Med Chem J 2008; 2:97-100. [PMID: 19662149 PMCID: PMC2709471 DOI: 10.2174/1874104500802010097] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 09/19/2008] [Accepted: 09/19/2008] [Indexed: 11/22/2022]
Abstract
In a brain-targeting prodrug approach for a metabolically stable enkephalin analogue DADLE, specific enzymes are utilized for in vivo prodrug activation. Prolyl oligopeptidase (POP) may be especially useful in this regard. In vitro metabolic stability of the putative metabolites of prodrugs having various “spacers” has shown that POP provides significantly faster release of DADLE from conjugates having dipeptidyl spacer (specifically Xaa-Pro or Xaa-Ala) than alternative peptidases utilized when single amino acids are used as spacers. In vitro half-lives measured in rat brain homogenate showed excellent correlation with CNS-mediated analgesia using the tail-flick model in rats providing, thus, an in vivo substantiation of the prodrug approach relying on POP as the peptidase to release DADLE.
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Affiliation(s)
- K Prokai-Tatrai
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
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