1
|
Iezhitsa I, Agarwal R, Agarwal P. Unveiling enigmatic essence of Sphingolipids: A promising avenue for glaucoma treatment. Vision Res 2024; 221:108434. [PMID: 38805893 DOI: 10.1016/j.visres.2024.108434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 05/05/2024] [Accepted: 05/06/2024] [Indexed: 05/30/2024]
Abstract
Treatment of glaucoma, the leading cause of irreversible blindness, remains challenging. The apoptotic loss of retinal ganglion cells (RGCs) in glaucoma is the pathological hallmark. Current treatments often remain suboptimal as they aim to halt RGC loss secondary to reduction of intraocular pressure. The pathophysiological targets for exploring direct neuroprotective approaches, therefore are highly relevant. Sphingolipids have emerged as significant target molecules as they are not only the structural components of various cell constituents, but they also serve as signaling molecules that regulate molecular pathways involved in cell survival and death. Investigations have shown that a critical balance among various sphingolipid species, particularly the ceramide and sphingosine-1-phosphate play a role in deciding the fate of the cell. In this review we briefly discuss the metabolic interconversion of sphingolipid species to get an insight into "sphingolipid rheostat", the dynamic balance among metabolites. Further we highlight the role of sphingolipids in the key pathophysiological mechanisms that lead to glaucomatous loss of RGCs. Lastly, we summarize the potential drug candidates that have been investigated for their neuroprotective effects in glaucoma via their effects on sphingolipid axis.
Collapse
|
2
|
Rahmati-Dehkordi F, Khanifar H, Najari N, Tamtaji Z, Talebi Taheri A, Aschner M, Shafiee Ardestani M, Mirzaei H, Dadgostar E, Nabavizadeh F, Tamtaji OR. Therapeutic Potential of Fingolimod on Psychological Symptoms and Cognitive Function in Neuropsychiatric and Neurological Disorders. Neurochem Res 2024:10.1007/s11064-024-04199-5. [PMID: 38918332 DOI: 10.1007/s11064-024-04199-5] [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: 05/08/2024] [Revised: 06/04/2024] [Accepted: 06/19/2024] [Indexed: 06/27/2024]
Abstract
Neuropsychiatric and neurological disorders pose a significant global health burden, highlighting the need for innovative therapeutic approaches. Fingolimod (FTY720), a common drug to treat multiple sclerosis, has shown promising efficacy against various neuropsychiatric and neurological disorders. Fingolimod exerts its neuroprotective effects by targeting multiple cellular and molecular processes, such as apoptosis, oxidative stress, neuroinflammation, and autophagy. By modulating Sphingosine-1-Phosphate Receptor activity, a key regulator of immune cell trafficking and neuronal function, it also affects synaptic activity and strengthens memory formation. In the hippocampus, fingolimod decreases glutamate levels and increases GABA levels, suggesting a potential role in modulating synaptic transmission and neuronal excitability. Taken together, fingolimod has emerged as a promising neuroprotective agent for neuropsychiatric and neurological disorders. Its broad spectrum of cellular and molecular effects, including the modulation of apoptosis, oxidative stress, neuroinflammation, autophagy, and synaptic plasticity, provides a comprehensive therapeutic approach for these debilitating conditions. Further research is warranted to fully elucidate the mechanisms of action of fingolimod and optimize its use in the treatment of neuropsychiatric and neurological disorders.
Collapse
Affiliation(s)
- Fatemeh Rahmati-Dehkordi
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Hadi Khanifar
- Department of Internal Medicine, Shahre-kord University of Medical Sciences, Shahre-kord, Iran
| | - Nazanin Najari
- Behavioral Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
- Student Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Zeinab Tamtaji
- Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Abdolkarim Talebi Taheri
- Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Mehdi Shafiee Ardestani
- Department of Radio Pharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamed Mirzaei
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran
| | - Ehsan Dadgostar
- Behavioral Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
- Student Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Fatemeh Nabavizadeh
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran.
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Omid Reza Tamtaji
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran.
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
3
|
Roggeri A, Olivero G, Usai C, Vanmierlo T, Pittaluga A. Presynaptic Release-Regulating Sphingosine 1-Phosphate 1/3 Receptors in Cortical Glutamatergic Terminals: Adaptations in EAE Mice and Impact of Therapeutic FTY720. Cells 2023; 12:2343. [PMID: 37830557 PMCID: PMC10571862 DOI: 10.3390/cells12192343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/13/2023] [Accepted: 09/20/2023] [Indexed: 10/14/2023] Open
Abstract
This study provides evidence of the existence of presynaptic inhibitory sphingosine-1-phosphate receptor 1 (S1P1R) and facilitatory S1P3R in cortical nerve endings (synaptosomes) of healthy mice. The conclusion relies on the findings that (i) the S1P1R agonist CS-2100 (0.1-30 nM) inhibits the 12 mM KCl-evoked glutamate exocytosis (quantified as the release of [3H]D-aspartate) while the S1P3R allosteric agonist CYM-5541 potentiates it and (ii) these effects are inhibited by the S1P1R antagonist Ex 26 (30-300 nM) and the S1P3R antagonist TY-52156 (100-1000 nM), respectively. Confocal microscopy and western blot analysis confirmed the presence of S1P1R and S1P3R proteins in cortical glutamatergic synaptosomes, which were scarcely accessible to biotin in a biotinylation study. Then, we demonstrated that S1P1R and S1P3R densities and their release activity are amplified in cortical synaptosomes of mice suffering from experimental autoimmune encephalomyelitis (EAE), despite receptors maintain their preferential internal distribution. Receptor changes recover following chronic oral therapeutic FTY720 (0.03 mg/Kg/day). These results improve our knowledge of the role of presynaptic release-regulating S1P1Rs and S1P3Rs controlling glutamate transmission in the CNS also unravelling functional adaptations during EAE that recover following chronic FTY720. In a whole, these findings provide new information on the central neuroprotectant activities of FTY720.
Collapse
Affiliation(s)
- Alessandra Roggeri
- Department of Pharmacy (DiFar), University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy; (A.R.); (G.O.)
| | - Guendalina Olivero
- Department of Pharmacy (DiFar), University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy; (A.R.); (G.O.)
| | - Cesare Usai
- Institute of Biophysics, National Research Council, Via De Marini 6, 16149 Genoa, Italy;
| | - Tim Vanmierlo
- Department of Neuroscience, Biomedical Research Institute, European Graduate School of Neuroscience, Hasselt University, B-3590 Hasselt, Belgium;
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neurosciences, Division Translational Neuroscience, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Anna Pittaluga
- Department of Pharmacy (DiFar), Center of Excellence for Biomedical Research, 3Rs Center, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy
- IRCCS Ospedale Policlinico San Martino, 16145 Genoa, Italy
| |
Collapse
|
4
|
Hsu SK, Lu CW, Chiu KM, Lee MY, Lin TY, Wang SJ. Mangiferin depresses vesicular glutamate release in synaptosomes from the rat cerebral cortex by decreasing synapsin I phosphorylation. Eur J Pharmacol 2023; 950:175772. [PMID: 37146708 DOI: 10.1016/j.ejphar.2023.175772] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/07/2023]
Abstract
Mangiferin is a glucosyl xanthone that has been shown to be a neuroprotective agent against brain disorders involving excess glutamate. However, the effect of mangiferin on the function of the glutamatergic system has not been investigated. In this study, we used synaptosomes from the rat cerebral cortex to investigate the effect of mangiferin on glutamate release and identify the possible underlying mechanism. We observed that mangiferin produced a concentration-dependent reduction in the release of glutamate elicited by 4-aminopyridine with an IC50 value of 25 μM. Inhibition of glutamate release was blocked by removing extracellular calcium and by treatment with the vacuolar-type H+-ATPase inhibitor bafilomycin A1, which prevents the uptake and storage of glutamate in vesicles. Moreover, we showed that mangiferin decreased the 4-aminopyridine-elicited FM1-43 release and synaptotagmin 1 luminal domain antibody (syt1-L ab) uptake from synaptosomes, which correlated with decreased synaptic vesicle exocytosis. Transmission electron microscopy in synaptosomes also showed that mangiferin attenuated the 4-aminopyridine-elicited decrease in the number of synaptic vesicles. In addition, antagonism of Ca2+/calmodulin-dependent kinase II (CaMKII) and protein kinase A (PKA) counteracted mangiferin's effect on glutamate release. Mangiferin also decreased the phosphorylation of CaMKII, PKA, and synapsin I elicited by 4-aminopyridine treatment. Our data suggest that mangiferin reduces PKA and CaMKII activation and synapsin I phosphorylation, which could decrease synaptic vesicle availability and lead to a subsequent reduction in vesicular glutamate release from synaptosomes.
Collapse
Affiliation(s)
- Szu-Kai Hsu
- School of Medicine, Fu Jen Catholic University, New Taipei City, 24205, Taiwan; Department of Neurosurgery, Cathay General Hospital, Taipei, 106438, Taiwan
| | - Cheng-Wei Lu
- Department of Anesthesiology, Far-Eastern Memorial Hospital, New Taipei City, 22060, Taiwan; Department of Mechanical Engineering, Yuan Ze University, Taoyuan, 32003, Taiwan
| | - Kuan-Ming Chiu
- Division of Cardiovascular Surgery, Cardiovascular Center, Far-Eastern Memorial Hospital, New Taipei City, 22060, Taiwan; Department of Electrical Engineering, Yuan Ze University, Taoyuan, 32003, Taiwan
| | - Ming-Yi Lee
- Department of Medical Research, Far-Eastern Memorial Hospital, New Taipei City, 22060, Taiwan
| | - Tzu-Yu Lin
- Department of Anesthesiology, Far-Eastern Memorial Hospital, New Taipei City, 22060, Taiwan; Department of Mechanical Engineering, Yuan Ze University, Taoyuan, 32003, Taiwan.
| | - Su-Jane Wang
- School of Medicine, Fu Jen Catholic University, New Taipei City, 24205, Taiwan; Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan City, 33303, Taiwan.
| |
Collapse
|
5
|
Leßmann V, Kartalou GI, Endres T, Pawlitzki M, Gottmann K. Repurposing drugs against Alzheimer's disease: can the anti-multiple sclerosis drug fingolimod (FTY720) effectively tackle inflammation processes in AD? J Neural Transm (Vienna) 2023:10.1007/s00702-023-02618-5. [PMID: 37014414 PMCID: PMC10374694 DOI: 10.1007/s00702-023-02618-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 03/02/2023] [Indexed: 04/05/2023]
Abstract
Therapeutic approaches providing effective medication for Alzheimer's disease (AD) patients after disease onset are urgently needed. Previous studies in AD mouse models and in humans suggested that physical exercise or changed lifestyle can delay AD-related synaptic and memory dysfunctions when treatment started in juvenile animals or in elderly humans before onset of disease symptoms. However, a pharmacological treatment that can reverse memory deficits in AD patients was thus far not identified. Importantly, AD disease-related dysfunctions have increasingly been associated with neuro-inflammatory mechanisms and searching for anti-inflammatory medication to treat AD seems promising. Like for other diseases, repurposing of FDA-approved drugs for treatment of AD is an ideally suited strategy to reduce the time to bring such medication into clinical practice. Of note, the sphingosine-1-phosphate analogue fingolimod (FTY720) was FDA-approved in 2010 for treatment of multiple sclerosis patients. It binds to the five different isoforms of Sphingosine-1-phosphate receptors (S1PRs) that are widely distributed across human organs. Interestingly, recent studies in five different mouse models of AD suggest that FTY720 treatment, even when starting after onset of AD symptoms, can reverse synaptic deficits and memory dysfunction in these AD mouse models. Furthermore, a very recent multi-omics study identified mutations in the sphingosine/ceramide pathway as a risk factor for sporadic AD, suggesting S1PRs as promising drug target in AD patients. Therefore, progressing with FDA-approved S1PR modulators into human clinical trials might pave the way for these potential disease modifying anti-AD drugs.
Collapse
Affiliation(s)
- Volkmar Leßmann
- Institute for Physiology, Medical Faculty, Otto-Von-Guericke-University, Leipziger Str. 44, 39120, Magdeburg, Germany.
- Center for Behavioral Brain Sciences, Magdeburg, Germany.
| | - Georgia-Ioanna Kartalou
- Institute for Physiology, Medical Faculty, Otto-Von-Guericke-University, Leipziger Str. 44, 39120, Magdeburg, Germany
- Institute of Neuro- and Sensory Physiology, Medical Faculty, Heinrich Heine University, Duesseldorf, Germany
| | - Thomas Endres
- Institute for Physiology, Medical Faculty, Otto-Von-Guericke-University, Leipziger Str. 44, 39120, Magdeburg, Germany
- Institute of Neuro- and Sensory Physiology, Medical Faculty, Heinrich Heine University, Duesseldorf, Germany
| | - Marc Pawlitzki
- Department of Neurology, Medical Faculty and University Hospital Düsseldorf, Duesseldorf, Germany
| | - Kurt Gottmann
- Institute of Neuro- and Sensory Physiology, Medical Faculty, Heinrich Heine University, Duesseldorf, Germany.
| |
Collapse
|
6
|
Hajipour S, Khombi Shooshtari M, Farbood Y, Ali Mard S, Sarkaki A, Moradi Chameh H, Sistani Karampour N, Ghafouri S. Fingolimod administration following hypoxia induced neonatal seizure can restore impaired long-term potentiation and memory performance in adult rats. Neuroscience 2023; 519:107-119. [PMID: 36990271 DOI: 10.1016/j.neuroscience.2023.03.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 02/18/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023]
Abstract
Neonatal seizures commonly caused by hypoxia can lead to long-term neurological outcomes. Early inflammation plays an important role in the pathology of these outcomes. Therefore, in the current study, we explored the long-term effects of Fingolimod (FTY720), an analog of sphingosine and potentsphingosine 1-phosphate(S1P) receptors modulator, as an anti-inflammatory and neuroprotective agent in attenuating anxiety, memory impairment, and possible alterations in gene expression of hippocampal inhibitory and excitatory receptors following hypoxia-induced neonatal seizure (HINS). Seizure was induced in 24 male and female pups (6 in each experimental group) at postnatal day 10 (P10) by premixed gas (5% oxygen/ 95% nitrogen) in a hypoxic chamber for 15 minutes. Sixty minutes after the onset of hypoxia, FTY720 (0.3 mg/kg) or saline (100 µl) was administered for 12 days (from P10 up to P21). Anxiety-like behavior and hippocampal memory function were assessed at P90 by elevated plus maze (EPM) and novel object recognition (NOR), respectively. Long-term potentiation (LTP) was recorded from hippocampal dentate gyrus region (DG) following stimulation of perforant pathway (PP). In addition, the hippocampal concentration of superoxide dismutase activity (SOD), malondialdehyde (MDA), and thiol as indices of oxidative stress were evaluated. Finally, the gene expression of NR2A subunit of N-Methyl-D-aspartic acid (NMDA) receptor, GluR2 subunit of (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) AMPA receptor and γ2 subunit of γ-Aminobutyric acid (GABAA) receptor were assessed at P90 by the quantitative real-time PCR. FTY720 significantly reduced later-life anxiety-like behavior, ameliorated object recognition memory and increased the amplitude and slope of the field excitatory postsynaptic potential (fEPSP) in the rats following HINS. These effects were associated with restoration of the hippocampal thiol content to the normal values and the regulatory role of FTY720 in the expression of hippocampal GABA and glutamate receptors subunits. In conclusion, FTY720 could restore the dysregulated gene expression of excitatory and inhibitory receptors. It also increased the reduced hippocampal thiol content, which was accompanied with attenuation of HINS-induced anxiety, reduced the impaired hippocampal related memory, and prevented hippocampal LTP deficits in later life following HINS.
Collapse
|
7
|
Skoug C, Martinsson I, Gouras GK, Meissner A, Duarte JMN. Sphingosine 1-Phoshpate Receptors are Located in Synapses and Control Spontaneous Activity of Mouse Neurons in Culture. Neurochem Res 2022; 47:3114-3125. [PMID: 35781853 PMCID: PMC9470655 DOI: 10.1007/s11064-022-03664-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/26/2022] [Accepted: 06/18/2022] [Indexed: 11/30/2022]
Abstract
Sphingosine-1-phosphate (S1P) is best known for its roles as vascular and immune regulator. Besides, it is also present in the central nervous system (CNS) where it can act as neuromodulator via five S1P receptors (S1PRs), and thus control neurotransmitter release. The distribution of S1PRs in the active zone and postsynaptic density of CNS synapses remains unknown. In the current study, we investigated the localization of S1PR1-5 in synapses of the mouse cortex. Cortical nerve terminals purified in a sucrose gradient were endowed with all five S1PRs. Further subcellular fractionation of cortical nerve terminals revealed S1PR2 and S1PR4 immunoreactivity in the active zone of presynaptic nerve terminals. Interestingly, only S1PR2 and S1PR3 immunoreactivity was found in the postsynaptic density. All receptors were present outside the active zone of nerve terminals. Neurons in the mouse cortex and primary neurons in culture showed immunoreactivity against all five S1PRs, and Ca2+ imaging revealed that S1P inhibits spontaneous neuronal activity in a dose-dependent fashion. When testing selective agonists for each of the receptors, we found that only S1PR1, S1PR2 and S1PR4 control spontaneous neuronal activity. We conclude that S1PR2 and S1PR4 are located in the active zone of nerve terminals and inhibit neuronal activity. Future studies need to test whether these receptors modulate stimulation-induced neurotransmitter release.
Collapse
Affiliation(s)
- Cecilia Skoug
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Isak Martinsson
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden
- Experimental Dementia Research Unit, Lund University, Lund, Sweden
| | - Gunnar K Gouras
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden
- Experimental Dementia Research Unit, Lund University, Lund, Sweden
| | - Anja Meissner
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
- Department of Physiology, University of Augsburg, Augsburg, Germany
| | - João M N Duarte
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden.
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden.
| |
Collapse
|
8
|
Lalkovicova M. Neuroprotective agents effective against radiation damage of central nervous system. Neural Regen Res 2022; 17:1885-1892. [PMID: 35142663 PMCID: PMC8848589 DOI: 10.4103/1673-5374.335137] [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: 11/04/2022] Open
Abstract
Ionizing radiation caused by medical treatments, nuclear events or even space flights can irreversibly damage structure and function of brain cells. That can result in serious brain damage, with memory and behavior disorders, or even fatal oncologic or neurodegenerative illnesses. Currently used treatments and drugs are mostly targeting biochemical processes of cell apoptosis, radiation toxicity, neuroinflammation, and conditions such as cognitive-behavioral disturbances or others that result from the radiation insult. With most drugs, the side effects and potential toxicity are also to be considered. Therefore, many agents have not been approved for clinical use yet. In this review, we focus on the latest and most effective agents that have been used in animal and also in the human research, and clinical treatments. They could have the potential therapeutical use in cases of radiation damage of central nervous system, and also in prevention considering their radioprotecting effect of nervous tissue.
Collapse
Affiliation(s)
- Mária Lalkovicova
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Russia; Slovak Academy of Sciences, Institute of Experimental Physics, Košice, Slovakia
| |
Collapse
|
9
|
Lin TY, Lu CW, Hsieh PW, Chiu KM, Lee MY, Wang SJ. Natural Product Isoliquiritigenin Activates GABA B Receptors to Decrease Voltage-Gate Ca 2+ Channels and Glutamate Release in Rat Cerebrocortical Nerve Terminals. Biomolecules 2021; 11:biom11101537. [PMID: 34680170 PMCID: PMC8534184 DOI: 10.3390/biom11101537] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 12/26/2022] Open
Abstract
Reduction in glutamate release is a key mechanism for neuroprotection and we investigated the effect of isoliquiritigenin (ISL), an active ingredient of Glycyrrhiza with neuroprotective activities, on glutamate release in rat cerebrocortical nerve terminals (synaptosomes). ISL produced a concentration-dependent inhibition of glutamate release and reduced the intraterminal [Ca2+] increase. The inhibition of glutamate release by ISL was prevented after removing extracellular Ca2+ or blocking P/Q-type Ca2+ channels. This inhibition was mediated through the γ-aminobutyric acid type B (GABAB) receptors because ISL was unable to inhibit glutamate release in the presence of baclofen (an GABAB agonist) or CGP3548 (an GABAB antagonist) and docking data revealed that ISL interacted with GABAB receptors. Furthermore, the ISL inhibition of glutamate release was abolished through the inhibition of Gi/o-mediated responses or Gβγ subunits, but not by 8-bromoadenosine 3′,5′-cyclic monophosphate or adenylate cyclase inhibition. The ISL inhibition of glutamate release was also abolished through the inhibition of protein kinase C (PKC), and ISL decreased the phosphorylation of PKC. Thus, we inferred that ISL, through GABAB receptor activation and Gβγ-coupled inhibition of P/Q-type Ca2+ channels, suppressed the PKC phosphorylation to cause a decrease in evoked glutamate release at rat cerebrocortical nerve terminals.
Collapse
Affiliation(s)
- Tzu-Yu Lin
- Department of Anesthesiology, Far-Eastern Memorial Hospital, Pan-Chiao District, New Taipei City 22060, Taiwan; (T.-Y.L.); (C.-W.L.)
- Department of Mechanical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan
| | - Cheng-Wei Lu
- Department of Anesthesiology, Far-Eastern Memorial Hospital, Pan-Chiao District, New Taipei City 22060, Taiwan; (T.-Y.L.); (C.-W.L.)
- Department of Mechanical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan
| | - Pei-Wen Hsieh
- Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 33303, Taiwan;
- Graduate Institute of Natural Products, School of Traditional Chinese Medicine, and Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33303, Taiwan
- Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
| | - Kuan-Ming Chiu
- Division of Cardiovascular Surgery, Cardiovascular Center, Far-Eastern Memorial Hospital, New Taipei 22060, Taiwan; (K.-M.C.); (M.-Y.L.)
- Department of Nursing, Asia Eastern University of Science and Technology, New Taipei City 22060, Taiwan
- Department of Photonics Engineering, Yuan Ze University, Taoyuan 32003, Taiwan
| | - Ming-Yi Lee
- Division of Cardiovascular Surgery, Cardiovascular Center, Far-Eastern Memorial Hospital, New Taipei 22060, Taiwan; (K.-M.C.); (M.-Y.L.)
| | - Su-Jane Wang
- Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 33303, Taiwan;
- School of Medicine, Fu Jen Catholic University, New Taipei City 24205, Taiwan
- Correspondence: ; Tel.: +88-62-2905-3465; Fax: +88-62-2905-2096
| |
Collapse
|