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Nascimento AA, Pereira-Figueiredo D, Borges-Martins VP, Kubrusly RC, Calaza KC. GABAergic system and chloride cotransporters as potential therapeutic targets to mitigate cell death in ischemia. J Neurosci Res 2024; 102:e25355. [PMID: 38808645 DOI: 10.1002/jnr.25355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 04/17/2024] [Accepted: 05/06/2024] [Indexed: 05/30/2024]
Abstract
Gamma aminobutyric acid (GABA) is a critical inhibitory neurotransmitter in the central nervous system that plays a vital role in modulating neuronal excitability. Dysregulation of GABAergic signaling, particularly involving the cotransporters NKCC1 and KCC2, has been implicated in various pathologies, including epilepsy, schizophrenia, autism spectrum disorder, Down syndrome, and ischemia. NKCC1 facilitates chloride influx, whereas KCC2 mediates chloride efflux via potassium gradient. Altered expression and function of these cotransporters have been associated with excitotoxicity, inflammation, and cellular death in ischemic events characterized by reduced cerebral blood flow, leading to compromised tissue metabolism and subsequent cell death. NKCC1 inhibition has emerged as a potential therapeutic approach to attenuate intracellular chloride accumulation and mitigate neuronal damage during ischemic events. Similarly, targeting KCC2, which regulates chloride efflux, holds promise for improving outcomes and reducing neuronal damage under ischemic conditions. This review emphasizes the critical roles of GABA, NKCC1, and KCC2 in ischemic pathologies and their potential as therapeutic targets. Inhibiting or modulating the activity of these cotransporters represents a promising strategy for reducing neuronal damage, preventing excitotoxicity, and improving neurological outcomes following ischemic events. Furthermore, exploring the interactions between natural compounds and NKCC1/KCC2 provides additional avenues for potential therapeutic interventions for ischemic injury.
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Affiliation(s)
- A A Nascimento
- Neurobiology of the Retina Laboratory, Department of Neurobiology and Graduate Program of Neurosciences, Institute of Biology, Fluminense Federal University, Niterói, Brazil
| | - D Pereira-Figueiredo
- Graduate Program in Biomedical Sciences (Physiology and Pharmacology), Fluminense Federal University, Niterói, Brazil
| | - V P Borges-Martins
- Laboratory of Neuropharmacology, Department of Physiology and Pharmacology, Biomedical Institute, Fluminense Federal University, Niterói, Brazil
| | - R C Kubrusly
- Laboratory of Neuropharmacology, Department of Physiology and Pharmacology, Biomedical Institute, Fluminense Federal University, Niterói, Brazil
| | - K C Calaza
- Neurobiology of the Retina Laboratory, Department of Neurobiology and Graduate Program of Neurosciences, Institute of Biology, Fluminense Federal University, Niterói, Brazil
- Graduate Program in Biomedical Sciences (Physiology and Pharmacology), Fluminense Federal University, Niterói, Brazil
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2
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Hosseinzadeh Sahafi O, Sardari M, Alijanpour S, Rezayof A. Shared Mechanisms of GABAergic and Opioidergic Transmission Regulate Corticolimbic Reward Systems and Cognitive Aspects of Motivational Behaviors. Brain Sci 2023; 13:brainsci13050815. [PMID: 37239287 DOI: 10.3390/brainsci13050815] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/12/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
The functional interplay between the corticolimbic GABAergic and opioidergic systems plays a crucial role in regulating the reward system and cognitive aspects of motivational behaviors leading to the development of addictive behaviors and disorders. This review provides a summary of the shared mechanisms of GABAergic and opioidergic transmission, which modulate the activity of dopaminergic neurons located in the ventral tegmental area (VTA), the central hub of the reward mechanisms. This review comprehensively covers the neuroanatomical and neurobiological aspects of corticolimbic inhibitory neurons that express opioid receptors, which act as modulators of corticolimbic GABAergic transmission. The presence of opioid and GABA receptors on the same neurons allows for the modulation of the activity of dopaminergic neurons in the ventral tegmental area, which plays a key role in the reward mechanisms of the brain. This colocalization of receptors and their immunochemical markers can provide a comprehensive understanding for clinicians and researchers, revealing the neuronal circuits that contribute to the reward system. Moreover, this review highlights the importance of GABAergic transmission-induced neuroplasticity under the modulation of opioid receptors. It discusses their interactive role in reinforcement learning, network oscillation, aversive behaviors, and local feedback or feedforward inhibitions in reward mechanisms. Understanding the shared mechanisms of these systems may lead to the development of new therapeutic approaches for addiction, reward-related disorders, and drug-induced cognitive impairment.
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Affiliation(s)
- Oveis Hosseinzadeh Sahafi
- Department of Animal Biology, School of Biology, College of Science, University of Tehran, Tehran 14155-6465, Iran
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Maryam Sardari
- Department of Animal Biology, School of Biology, College of Science, University of Tehran, Tehran 14155-6465, Iran
| | - Sakineh Alijanpour
- Department of Biology, Faculty of Science, Gonbad Kavous University, Gonbad Kavous 4971799151, Iran
| | - Ameneh Rezayof
- Department of Animal Biology, School of Biology, College of Science, University of Tehran, Tehran 14155-6465, Iran
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Hwang Y, Park JH, Kim HC, Shin EJ. GABA B receptor activation alters astrocyte phenotype changes induced by trimethyltin via ERK signaling in the dentate gyrus of mice. Life Sci 2023; 319:121529. [PMID: 36841471 DOI: 10.1016/j.lfs.2023.121529] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/11/2023] [Accepted: 02/20/2023] [Indexed: 02/25/2023]
Abstract
AIMS We examined the effect of γ-aminobutyric acid (GABA)B receptor activation on astrocyte phenotype changes induced by trimethyltin (TMT) in the dentate gyrus of mice. MAIN METHODS Male C57BL/6N mice received TMT (2.6 mg/kg, i.p.), and the expression of GABAB receptors was evaluated in the hippocampus. The GABAB receptor agonist baclofen (2.5, 5, or 10 mg/kg, i.p. × 5 at 12-h intervals) was administered 3-5 days after TMT treatment, and the expression of Iba-1, GFAP, and astrocyte phenotype markers was evaluated 6 days after TMT. SL327 (30 mg/kg, i.p.), an extracellular signal-related kinase (ERK) inhibitor, was administered 1 h after each baclofen treatment. KEY FINDINGS TMT insult significantly induced the astroglial expression of GABAB receptors in the dentate molecular layer. Baclofen significantly promoted the expression of S100A10, EMP1, and CD109, but not that of C3, GGTA1, and MX1 induced by TMT. In addition, baclofen significantly increased the TMT-induced expression of p-ERK in the dentate molecular layer. Interestingly, p-ERK was more colocalized with S100A10 than with C3 after TMT insult, and a significant positive correlation was found between the expression of p-ERK and S100A10. Consistently, SL327 reversed the effect of baclofen on astrocyte phenotype changes. Baclofen also enhanced the TMT-induced astroglial expression of glial cell-derived neurotrophic factor (GDNF), an anti-inflammatory astrocytes-to-microglia mediator, and consequently attenuated Iba-1 expression and delayed apoptotic neuronal death. SIGNIFICANCE Our results suggest that GABAB receptor activation increases S100A10-positive anti-inflammatory astrocytes and astroglial GDNF expression via ERK signaling after TMT excitotoxicity in the dentate molecular layer of mice.
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Affiliation(s)
- Yeonggwang Hwang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Jung Hoon Park
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea.
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea.
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Ramezani M, Meymand AZ, Khodagholi F, Kamsorkh HM, Asadi E, Noori M, Rahimian K, Shahrbabaki AS, Talebi A, Parsaiyan H, Shiravand S, Darbandi N. A role for flavonoids in the prevention and/or treatment of cognitive dysfunction, learning, and memory deficits: a review of preclinical and clinical studies. Nutr Neurosci 2023; 26:156-172. [PMID: 35152858 DOI: 10.1080/1028415x.2022.2028058] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Natural food substances, due to high rates of antioxidants, antiviral and anti-inflammatory properties, have been proposed to have the potential for the prevention or treatment of cognitive deficits, learning and memory deficits and neuro inflammation. In particular, medicinal plants with rich amounts of beneficial components such as flavonoids are one of the most promising therapeutic candidates for the cognitive deficit and memory loss. Herein, we aimed to review the impact of medicinal plants with focus on flavonoids on cognitive dysfunction, learning and memory loss by considering their signaling pathways. METHODS We extracted 93 preclinical and clinical studies related to the effects of flavonoids on learning and memory and cognition from published papers between 2000 and 2021 in the MEDLINE/PubMed, Cochrane Library, SCOPUS, and Airiti Library databases. RESULTS In the preclinical studies, at least there seem to be two main neurological and biological processes in which flavonoids contribute to the improvement and/or prevention of learning, memory deficit and cognitive dysfunction: (1) Regulation of neurotransmission system and (2) Enhancement of neurogenesis, synaptic plasticity and neuronal survival. CONCLUSION Although useful effects of flavonoids on learning and memory in preclinical investigations have been approved, more clinical trials are required to find out whether flavonoids and/or other ingredients of plants have the potent to prevent or treat neurodegenerative disorders.
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Affiliation(s)
- Matin Ramezani
- Department of Biology, Faculty of Science, Arak University, Arak, Iran
| | | | - Fariba Khodagholi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Ehsan Asadi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mitra Noori
- Department of Biology, Faculty of Science, Arak University, Arak, Iran
| | - Kimia Rahimian
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Aisa Talebi
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hanieh Parsaiyan
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sepideh Shiravand
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Niloufar Darbandi
- Department of Biology, Faculty of Science, Arak University, Arak, Iran
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5
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Balakrishnan K, Hleihil M, Bhat MA, Ganley RP, Vaas M, Klohs J, Zeilhofer HU, Benke D. Targeting the interaction of GABA B receptors with CaMKII with an interfering peptide restores receptor expression after cerebral ischemia and inhibits progressive neuronal death in mouse brain cells and slices. Brain Pathol 2022; 33:e13099. [PMID: 35698024 PMCID: PMC9836377 DOI: 10.1111/bpa.13099] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/29/2022] [Indexed: 01/21/2023] Open
Abstract
Cerebral ischemia is the leading cause for long-term disability and mortality in adults due to massive neuronal death. Currently, there is no pharmacological treatment available to limit progressive neuronal death after stroke. A major mechanism causing ischemia-induced neuronal death is the excessive release of glutamate and the associated overexcitation of neurons (excitotoxicity). Normally, GABAB receptors control neuronal excitability in the brain via prolonged inhibition. However, excitotoxic conditions rapidly downregulate GABAB receptors via a CaMKII-mediated mechanism and thereby diminish adequate inhibition that could counteract neuronal overexcitation and neuronal death. To prevent the deleterious downregulation of GABAB receptors, we developed a cell-penetrating synthetic peptide (R1-Pep) that inhibits the interaction of GABAB receptors with CaMKII. Administration of this peptide to cultured cortical neurons exposed to excitotoxic conditions restored cell surface expression and function of GABAB receptors. R1-Pep did not affect CaMKII expression or activity but prevented its T286 autophosphorylation that renders it autonomously and persistently active. Moreover, R1-Pep counteracted the aberrant downregulation of G protein-coupled inwardly rectifying K+ channels and the upregulation of N-type voltage-gated Ca2+ channels, the main effectors of GABAB receptors. The restoration of GABAB receptors activated the Akt survival pathway and inhibited excitotoxic neuronal death with a wide time window in cultured neurons. Restoration of GABAB receptors and neuroprotective activity of R1-Pep was verified by using brain slices prepared from mice after middle cerebral artery occlusion (MCAO). Treatment with R1-Pep restored normal GABAB receptor expression and GABA receptor-mediated K+ channel currents. This reduced MCAO-induced neuronal excitability and inhibited neuronal death. These results support the hypothesis that restoration of GABAB receptor expression under excitatory conditions provides neuroprotection and might be the basis for the development of a selective intervention to inhibit progressive neuronal death after ischemic stroke.
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Affiliation(s)
- Karthik Balakrishnan
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland,Neuroscience Center ZurichUniversity of Zurich and ETH ZurichZurichSwitzerland,Present address:
Dewpoint Therapeutics GMBHDresdenGermany
| | - Mohammad Hleihil
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland,Neuroscience Center ZurichUniversity of Zurich and ETH ZurichZurichSwitzerland
| | - Musadiq A. Bhat
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland
| | - Robert P. Ganley
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland
| | - Markus Vaas
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland,Present address:
Clinical Trial Center ZurichUniversity Hospital of ZurichZurichSwitzerland
| | - Jan Klohs
- Neuroscience Center ZurichUniversity of Zurich and ETH ZurichZurichSwitzerland,Institute for Biomedical Engineering, University of Zurich and ETH ZurichZurichSwitzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland,Neuroscience Center ZurichUniversity of Zurich and ETH ZurichZurichSwitzerland,Drug Discovery Network ZurichZurichSwitzerland,Institute of Pharmaceutical Sciences, ETH ZurichZurichSwitzerland
| | - Dietmar Benke
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland,Neuroscience Center ZurichUniversity of Zurich and ETH ZurichZurichSwitzerland,Drug Discovery Network ZurichZurichSwitzerland
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6
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Chen C, Bu L, Liu H, Rang Y, Huang H, Xiao X, Ou G, Liu C. Learning and memory impairment induced by 1,4-butanediol is regulated by ERK1/2-CREB-BDNF signaling pathways in PC12 cells. Metab Brain Dis 2022; 37:1451-1463. [PMID: 35348994 DOI: 10.1007/s11011-022-00963-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 03/14/2022] [Indexed: 01/03/2023]
Abstract
1,4-butanediol (1,4-BD) is a known γ-hydroxybutyric acid (GHB) precursor which affects the nervous system after ingestion, leading to uncontrolled behavioral consequences. In the present study, we investigated whether 1,4-BD induces oxidative stress and inflammation in PC12 cells and evaluated the toxic effects of 1,4-BD associates with learning and memory. CCK-8 results revealed a dose-effect relationship between the cell viability of PC12 cells and 1,4-BD when the duration of action was 2 h or 4 h. Assay kits results showed that 1,4-BD decreased the levels of Glutathione (GSH), Glutathione peroxidase (GSH-px), Superoxide dismutase (SOD), Acetylcholine (Ach) and increased the levels of Malondialdehyde (MDA), Nitric oxide (NO) and Acetylcholinesterase (AchE). Elisa kits results indicated that 1,4-BD decreased the levels of synaptophysin I (SYN-1), Postsynaptic density protein-95 (PSD-95), Growth associated protein-43 (GAP-43) and increased the levels of Tumor necrosis factor alpha (TNF-α) and Interleukin- 6 (IL-6). RT-PCR results showed that the mRNA levels of PSD-95, SYN-1 and GAP-43 were significantly decreased. The expression of phosphorylation extracellular signal-regulated protein kinase 1/2 (p-ERK1/2), phosphorylation cAMP response element binding protein (p-CREB) and brain-derived neurotrophic factor (BDNF) proteins were significantly decreased in PC12 cells by protein blotting. Overall, these results suggest that 1,4-BD may affect synaptic plasticity via the ERK1/2-CREB-BDNF pathway, leading to Ach release reduction and ultimately to learning and memory impairment. Furthermore, oxidative stress and inflammation induced by 1,4-BD may also result in learning and memory deficits. These findings will enrich the toxicity data of 1.4-BD associated with learning and memory impairment.
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Affiliation(s)
- Congying Chen
- College of Food Science, South China Agricultural University, Guang zhou, 510642, China
| | - Lingling Bu
- College of Food Science, South China Agricultural University, Guang zhou, 510642, China
| | - Huan Liu
- College of Food Science, South China Agricultural University, Guang zhou, 510642, China
| | - Yifeng Rang
- College of Food Science, South China Agricultural University, Guang zhou, 510642, China
| | - Huiying Huang
- College of Food Science, South China Agricultural University, Guang zhou, 510642, China
| | - Xueman Xiao
- College of Food Science, South China Agricultural University, Guang zhou, 510642, China
| | - Genghua Ou
- College of Food Science, South China Agricultural University, Guang zhou, 510642, China
| | - Chunhong Liu
- College of Food Science, South China Agricultural University, Guang zhou, 510642, China.
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7
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Wang Y, Gai S, Zhang W, Huang X, Ma S, Huo Y, Wu Y, Tu H, Pin JP, Rondard P, Xu C, Liu J. The GABA B receptor mediates neuroprotection by coupling to G 13. Sci Signal 2021; 14:eaaz4112. [PMID: 34665640 DOI: 10.1126/scisignal.aaz4112] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Yunyun Wang
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Siyu Gai
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Wenhua Zhang
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Xuetao Huang
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Shumin Ma
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Yujia Huo
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Yichen Wu
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Haijun Tu
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Chanjuan Xu
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Jianfeng Liu
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China.,Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510005 Guangzhou, China
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8
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GABA B Receptor Chemistry and Pharmacology: Agonists, Antagonists, and Allosteric Modulators. Curr Top Behav Neurosci 2021; 52:81-118. [PMID: 34036555 DOI: 10.1007/7854_2021_232] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The GABAB receptors are metabotropic G protein-coupled receptors (GPCRs) that mediate the actions of the primary inhibitory neurotransmitter, γ-aminobutyric acid (GABA). In the CNS, GABA plays an important role in behavior, learning and memory, cognition, and stress. GABA is also located throughout the gastrointestinal (GI) tract and is involved in the autonomic control of the intestine and esophageal reflex. Consequently, dysregulated GABAB receptor signaling is associated with neurological, mental health, and gastrointestinal disorders; hence, these receptors have been identified as key therapeutic targets and are the focus of multiple drug discovery efforts for indications such as muscle spasticity disorders, schizophrenia, pain, addiction, and gastroesophageal reflex disease (GERD). Numerous agonists, antagonists, and allosteric modulators of the GABAB receptor have been described; however, Lioresal® (Baclofen; β-(4-chlorophenyl)-γ-aminobutyric acid) is the only FDA-approved drug that selectively targets GABAB receptors in clinical use; undesirable side effects, such as sedation, muscle weakness, fatigue, cognitive deficits, seizures, tolerance and potential for abuse, limit their therapeutic use. Here, we review GABAB receptor chemistry and pharmacology, presenting orthosteric agonists, antagonists, and positive and negative allosteric modulators, and highlight the therapeutic potential of targeting GABAB receptor modulation for the treatment of various CNS and peripheral disorders.
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Porcu A, Mostallino R, Serra V, Melis M, Sogos V, Beggiato S, Ferraro L, Manetti F, Gianibbi B, Bettler B, Corelli F, Mugnaini C, Castelli MP. COR758, a negative allosteric modulator of GABA B receptors. Neuropharmacology 2021; 189:108537. [PMID: 33798546 DOI: 10.1016/j.neuropharm.2021.108537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/20/2021] [Accepted: 03/22/2021] [Indexed: 10/21/2022]
Abstract
Allosteric modulators of G protein coupled receptors (GPCRs), including GABABRs (GABABRs), are promising therapeutic candidates. While several positive allosteric modulators (PAM) of GABABRs have been characterized, only recently the first negative allosteric modulator (NAM) has been described. In the present study, we report the characterization of COR758, which acts as GABABR NAM in rat cortical membranes and CHO cells stably expressing GABABRs (CHO-GABAB). COR758 failed to displace the antagonist [3H]CGP54626 from the orthosteric binding site of GABABRs showing that it acts through an allosteric binding site. Docking studies revealed a possible new allosteric binding site for COR758 in the intrahelical pocket of the GABAB1 monomer. COR758 inhibited basal and GABABR-stimulated O-(3-[35Sthio)-triphosphate ([35S]GTPγS) binding in brain membranes and blocked the enhancement of GABABR-stimulated [35S]GTPγS binding by the PAM GS39783. Bioluminescent resonance energy transfer (BRET) measurements in CHO-GABAB cells showed that COR758 inhibited G protein activation by GABA and altered GABABR subunit rearrangements. Additionally, the compound altered GABABR-mediated signaling such as baclofen-induced inhibition of cAMP production in transfected HEK293 cells, agonist-induced Ca2+ mobilization as well as baclofen and the ago-PAM CGP7930 induced phosphorylation of extracellular signal-regulated kinases (ERK1/2) in CHO-GABAB cells. COR758 also prevented baclofen-induced outward currents recorded from rat dopamine neurons, substantiating its property as a NAM for GABABRs. Altogether, these data indicate that COR758 inhibits G protein signaling by GABABRs, likely by interacting with an allosteric binding-site. Therefore, COR758 might serve as a scaffold to develop additional NAMs for therapeutic intervention.
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Affiliation(s)
- Alessandra Porcu
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy; Department of Biomedicine, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland
| | - Rafaela Mostallino
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy
| | - Valeria Serra
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy
| | - Miriam Melis
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy
| | - Valeria Sogos
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy
| | - Sarah Beggiato
- Department of Life Sciences and Biotechnology, Section of Medicinal and Health Products, and LTTA Center, University of Ferrara, Ferrara, Italy; Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, 66100, Chieti, Italy
| | - Luca Ferraro
- Department of Life Sciences and Biotechnology, Section of Medicinal and Health Products, and LTTA Center, University of Ferrara, Ferrara, Italy
| | - Fabrizio Manetti
- Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, I-53100, Siena, SI, Italy
| | - Beatrice Gianibbi
- Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, I-53100, Siena, SI, Italy
| | - Bernhard Bettler
- Department of Biomedicine, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland
| | - Federico Corelli
- Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, I-53100, Siena, SI, Italy
| | - Claudia Mugnaini
- Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, I-53100, Siena, SI, Italy
| | - M Paola Castelli
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy; Guy Everett Laboratory, University of Cagliari, 09042, Monserrato, Italy; Center of Excellence "Neurobiology of Addiction", University of Cagliari, 09042, Monserrato, Italy.
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10
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Evenseth LSM, Gabrielsen M, Sylte I. The GABA B Receptor-Structure, Ligand Binding and Drug Development. Molecules 2020; 25:molecules25133093. [PMID: 32646032 PMCID: PMC7411975 DOI: 10.3390/molecules25133093] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 11/17/2022] Open
Abstract
The γ-aminobutyric acid (GABA) type B receptor (GABAB-R) belongs to class C of the G-protein coupled receptors (GPCRs). Together with the GABAA receptor, the receptor mediates the neurotransmission of GABA, the main inhibitory neurotransmitter in the central nervous system (CNS). In recent decades, the receptor has been extensively studied with the intention being to understand pathophysiological roles, structural mechanisms and develop drugs. The dysfunction of the receptor is linked to a broad variety of disorders, including anxiety, depression, alcohol addiction, memory and cancer. Despite extensive efforts, few compounds are known to target the receptor, and only the agonist baclofen is approved for clinical use. The receptor is a mandatory heterodimer of the GABAB1 and GABAB2 subunits, and each subunit is composed of an extracellular Venus Flytrap domain (VFT) and a transmembrane domain of seven α-helices (7TM domain). In this review, we briefly present the existing knowledge about the receptor structure, activation and compounds targeting the receptor, emphasizing the role of the receptor in previous and future drug design and discovery efforts.
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Affiliation(s)
- Linn Samira Mari Evenseth
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Mari Gabrielsen
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Ingebrigt Sylte
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
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11
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Albert-Gascó H, Ros-Bernal F, Castillo-Gómez E, Olucha-Bordonau FE. MAP/ERK Signaling in Developing Cognitive and Emotional Function and Its Effect on Pathological and Neurodegenerative Processes. Int J Mol Sci 2020; 21:E4471. [PMID: 32586047 PMCID: PMC7352860 DOI: 10.3390/ijms21124471] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/14/2020] [Accepted: 06/17/2020] [Indexed: 12/13/2022] Open
Abstract
The signaling pathway of the microtubule-associated protein kinase or extracellular regulated kinase (MAPK/ERK) is a common mechanism of extracellular information transduction from extracellular stimuli to the intracellular space. The transduction of information leads to changes in the ongoing metabolic pathways and the modification of gene expression patterns. In the central nervous system, ERK is expressed ubiquitously, both temporally and spatially. As for the temporal ubiquity, this signaling system participates in three key moments: (i) Embryonic development; (ii) the early postnatal period; and iii) adulthood. During embryonic development, the system is partly responsible for the patterning of segmentation in the encephalic vesicle through the FGF8-ERK pathway. In addition, during this period, ERK directs neurogenesis migration and the final fate of neural progenitors. During the early postnatal period, ERK participates in the maturation process of dendritic trees and synaptogenesis. During adulthood, ERK participates in social and emotional behavior and memory processes, including long-term potentiation. Alterations in mechanisms related to ERK are associated with different pathological outcomes. Genetic alterations in any component of the ERK pathway result in pathologies associated with neural crest derivatives and mental dysfunctions associated with autism spectrum disorders. The MAP-ERK pathway is a key element of the neuroinflammatory pathway triggered by glial cells during the development of neurodegenerative diseases, such as Parkinson's and Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis, as well as prionic diseases. The process triggered by MAPK/ERK activation depends on the stage of development (mature or senescence), the type of cellular element in which the pathway is activated, and the anatomic neural structure. However, extensive gaps exist with regards to the targets of the phosphorylated ERK in many of these processes.
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Affiliation(s)
- Héctor Albert-Gascó
- UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Hills Road, Cambridge CB2 0AH, UK;
| | - Francisco Ros-Bernal
- U.P Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Avda. de Vicent Sos Baynat s/n, 12071 Castelló de la Plana, Spain; (F.R.-B.); (E.C.-G.)
| | - Esther Castillo-Gómez
- U.P Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Avda. de Vicent Sos Baynat s/n, 12071 Castelló de la Plana, Spain; (F.R.-B.); (E.C.-G.)
- Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Planta 0, 28029 Madrid, Spain
| | - Francisco E. Olucha-Bordonau
- U.P Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Avda. de Vicent Sos Baynat s/n, 12071 Castelló de la Plana, Spain; (F.R.-B.); (E.C.-G.)
- Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Planta 0, 28029 Madrid, Spain
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12
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Extracellular Signal-Regulated Kinases Mediate an Autoregulation of GABA B-Receptor-Activated Whole-Cell Current in Locus Coeruleus Neurons. Sci Rep 2020; 10:7869. [PMID: 32398643 PMCID: PMC7217949 DOI: 10.1038/s41598-020-64292-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 04/09/2020] [Indexed: 11/09/2022] Open
Abstract
The norepinephrine-releasing neurons in the locus coeruleus (LC) are well known to regulate wakefulness/arousal. They display active firing during wakefulness and a decreased discharge rate during sleep. We have previously reported that LC neurons express large numbers of GABAB receptors (GABABRs) located at peri-/extrasynaptic sites and are subject to tonic inhibition due to the continuous activation of GABABRs by ambient GABA, which is significantly higher during sleep than during wakefulness. In this study, we further showed using western blot analysis that the activation of GABABRs with baclofen could increase the level of phosphorylated extracellular signal-regulated kinase 1 (ERK1) in LC tissue. Recordings from LC neurons in brain slices showed that the inhibition of ERK1/2 with U0126 and FR180204 accelerated the decay of whole-cell membrane current induced by prolonged baclofen application. In addition, the inhibition of ERK1/2 also increased spontaneous firing and reduced tonic inhibition of LC neurons after prolonged exposure to baclofen. These results suggest a new role of GABABRs in mediating ERK1-dependent autoregulation of the stability of GABABR-activated whole-cell current, in addition to its well-known effect on gated potassium channels, to cause a tonic current in LC neurons.
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13
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Liu F, Zhang YY, Song N, Lin J, Liu MK, Huang CL, Zhou C, Wang H, Wang M, Shen JF. GABA B receptor activation attenuates inflammatory orofacial pain by modulating interleukin-1β in satellite glial cells: Role of NF-κB and MAPK signaling pathways. Brain Res Bull 2019; 149:240-250. [PMID: 31034945 DOI: 10.1016/j.brainresbull.2019.04.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 03/26/2019] [Accepted: 04/22/2019] [Indexed: 02/05/2023]
Abstract
Orofacial inflammation could activate satellite glial cells (SGCs) in the trigeminal ganglion (TG) to produce interleukin 1β (IL-1β) which plays crucial roles in the development of inflammatory pain. Recent studies have shown that gamma-amino butyric acid-B (GABAB) receptor could modulate the expression of inflammatory cytokines in microglia and astrocytes in the spinal cord. The objective of this study was to investigate whether GABAB receptors in TG SGCs attenuate inflammatory facial pain via mediating IL-1β following inflammation and its mechanisms. Complete Freund's adjuvant (CFA) was injected into the whisker pad of rats to induce inflammation in vivo. Lipopolysaccharide (LPS) was added to culture medium to activate SGCs in vitro. Behavioral measures showed that microinjection of baclofen (a selective GABAB receptor agonist) into the TG ameliorated the mechanical allodynia of CFA-treated rats. Interestingly, baclofen pretreatment inhibited SGC activation and IL-1β production, however, preserved the decreased expression of GABAB receptors in SGCs activated by CFA in vivo and LPS in vitro. In addition, baclofen suppressed the increased expression of p-NF- κ B p65, p-I κ Bα, and p-p38 MAPK, while reversed the decreased production of I κ Bα, and further enhanced the increased expression of p-ERK(1/2) in LPS-treated SGCs in vitro. Finally, those effects of baclofen were abolished by saclofen (a specific GABAB receptor antagonist) co-administration. Altogether, these results demonstrated for the first time that activation of GABAB receptor might inhibit IL-1β production by suppressing NF- κ B and p38 MAPK signaling pathway activation and restore GABAB receptor expression in SGCs to attenuate inflammatory facial pain.
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Affiliation(s)
- Fei Liu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Yan-Yan Zhang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Ning Song
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Jiu Lin
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Meng-Ke Liu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Chao-Lan Huang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Cheng Zhou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Hang Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Min Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Jie-Fei Shen
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province, 610041, China.
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14
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Specific activation of mGlu2 induced IGF-1R transactivation in vitro through FAK phosphorylation. Acta Pharmacol Sin 2019; 40:460-467. [PMID: 29946167 DOI: 10.1038/s41401-018-0033-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/20/2018] [Indexed: 01/17/2023] Open
Abstract
Metabotropic glutamate receptor 2 (mGlu2) belongs to the group-II metabotropic glutamate (mGlu) receptors and is a neurotransmitter G protein-coupled receptor. The group-II mGlu receptors are promising antipsychotic targets, but the specific role of mGlu2 signaling remains unclear. Receptor tyrosine kinases (RTKs) are also believed to participate in brain pathogenesis. To investigate whether there is any communication between mGlu2 and RTKs, we generated a CHO-mGlu2 cell line that stably expresses mGlu2 and showed that activation of mGlu2 by LY379268, a group II mGlu agonist, was able to transactivate insulin-like growth factor 1 receptor (IGF-1R). We further determined that the Gi/o protein, Gβγ subunits, phospholipase C, and focal adhesion kinase (FAK) were involved in the IGF-1R transactivation signaling axis, which further induced the phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2) and cAMP response element-binding protein. In primary mouse cortical neurons, similar signaling pathways were observed when mGlu2 were stimulated by LY487379, an mGlu2 positive allosteric modulator. Transactivation of IGF-1R through FAK in response to mGlu2 should provide a better understanding of the association of mGlu2 with brain disease.
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15
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Niu X, Liu F, Zhou Y, Zhou Z, Zhou D, Wang T, Li Z, Ye X, Yu Y, Weng X, Zhang H, Ye J, Liao M, Liu Y, Chen Z, Lu S. Genome-wide DNA Methylation Analysis Reveals GABBR2 as a Novel Epigenetic Target for EGFR 19 Deletion Lung Adenocarcinoma with Induction Erlotinib Treatment. Clin Cancer Res 2017; 23:5003-5014. [PMID: 28490462 DOI: 10.1158/1078-0432.ccr-16-2688] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/05/2017] [Accepted: 05/02/2017] [Indexed: 11/16/2022]
Abstract
Purpose: The past decade has witnessed the rapid development of personalized targeted therapies in lung cancer. It is still unclear whether epigenetic changes are involved in the response to tyrosine kinase inhibitor (TKI) treatment in epidermal growth factor receptor (EGFR)-mutated lung cancer.Experimental Design: Methyl-sensitive cut counting sequencing (MSCC) was applied to investigate the methylation changes in paired tissues before and after erlotinib treatment for 42 days with partial response (PR) from stage IIIa (N2) lung adenocarcinoma patients (N = 2) with EGFR 19 deletion. The Sequenom EpiTYPER assay was used to validate the changed methylated candidate genes. Up- or downregulation of the candidate gene was performed to elucidate the potential mechanism in the regulation of erlotinib treatment response.Results: Sixty aberrant methylated genes were screened using MSCC sequencing. Two aberrant methylated genes, CBFA2T3 and GABBR2, were clearly validated. A same differential methylated region (DMR) between exon 2 and exon 3 of GABBR2 gene was confirmed consistently in both patients. GABBR2 was significantly downregulated in EGFR 19 deletion cells, HCC4006 and HCC827, but remained conserved in EGFR wild-type A549 cells after erlotinib treatment. Upregulation of GABBR2 expression significantly rescued erlotinib-induced apoptosis in HCC827 cells. GABBR2 was significantly downregulated, along with the reduction of S6, p-p70 S6, and p-ERK1/2, demonstrating that GABBR2 may play an important role in EGFR signaling through the ERK1/2 pathway.Conclusions: We demonstrated that GABBR2 gene might be a novel potential epigenetic treatment target with induction erlotinib treatment for stage IIIa (N2) EGFR 19 deletion lung adenocarcinoma. Clin Cancer Res; 23(17); 5003-14. ©2017 AACR.
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Affiliation(s)
- Xiaomin Niu
- Department of Shanghai Lung Cancer Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Fatao Liu
- Department of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Institute of Biliary Tract Disease, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
| | - Yi Zhou
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, P.R. China
| | - Zhen Zhou
- Department of Shanghai Lung Cancer Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Daizhan Zhou
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Ting Wang
- Department of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Institute of Biliary Tract Disease, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
| | - Ziming Li
- Department of Shanghai Lung Cancer Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Xiangyun Ye
- Department of Shanghai Lung Cancer Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Yongfeng Yu
- Department of Shanghai Lung Cancer Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Xiaoling Weng
- Institutes of Biomedical Sciences, Fudan University, Shanghai, P.R. China.,Key Laboratory of Molecular Medicine, The Ministry of Education, Department of Biochemistry and Molecular Biology, Fudan University Shanghai Medical College, Shanghai, P.R. China
| | - Hong Zhang
- Institutes of Biomedical Sciences, Fudan University, Shanghai, P.R. China.,Key Laboratory of Molecular Medicine, The Ministry of Education, Department of Biochemistry and Molecular Biology, Fudan University Shanghai Medical College, Shanghai, P.R. China
| | - Junyi Ye
- Institutes of Biomedical Sciences, Fudan University, Shanghai, P.R. China.,Key Laboratory of Molecular Medicine, The Ministry of Education, Department of Biochemistry and Molecular Biology, Fudan University Shanghai Medical College, Shanghai, P.R. China
| | - Meilin Liao
- Department of Shanghai Lung Cancer Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Yun Liu
- Institutes of Biomedical Sciences, Fudan University, Shanghai, P.R. China
| | - Zhiwei Chen
- Department of Shanghai Lung Cancer Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Shun Lu
- Department of Shanghai Lung Cancer Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China.
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16
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KK-92A, a novel GABA B receptor positive allosteric modulator, attenuates nicotine self-administration and cue-induced nicotine seeking in rats. Psychopharmacology (Berl) 2017; 234:1633-1644. [PMID: 28382542 DOI: 10.1007/s00213-017-4594-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 03/11/2017] [Indexed: 01/03/2023]
Abstract
RATIONALE GABAB receptors (GABABR) play a critical role in GABAergic neurotransmission in the brain and are thought to be one of the most promising targets for the treatment of drug addiction. GABABR positive allosteric modulators (PAMs) have shown promise as potential anti-addictive therapies, as they lack the sedative and muscle relaxant properties of full GABAB receptor agonists such as baclofen. OBJECTIVES The present study was aimed at developing novel, selective, and potent GABABR PAMs with efficacy on abuse-related effects of nicotine. RESULTS We synthetized ~100 analogs of BHF177, a GABABR PAM that has been shown to inhibit nicotine taking and seeking, and tested their activity in multiple cell-based functional assays. Among these compounds, KK-92A displayed superior PAM properties at the GABABR. Interestingly, our results revealed the existence of pathway-selective differential modulation of GABABR signaling by the structurally related GABABR allosteric modulators BHF177 and KK-92A. In vivo, similarly to BHF177, KK-92A inhibited intravenous nicotine self-administration under both fixed- and progressive-ratio schedules of reinforcement in rats. In contrast to BHF177, KK-92A had no effect on food self-administration. Furthermore, KK-92A decreased cue-induced nicotine-seeking behavior without affecting food seeking. CONCLUSIONS These results indicate that KK-92A is a selective GABABR PAM with efficacy in inhibition of the primary reinforcing and incentive motivational effects of nicotine, and attenuation of nicotine seeking, further confirming that GABABR PAMs may be useful antismoking medications.
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17
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Xia S, He C, Zhu Y, Wang S, Li H, Zhang Z, Jiang X, Liu J. GABA BR-Induced EGFR Transactivation Promotes Migration of Human Prostate Cancer Cells. Mol Pharmacol 2017; 92:265-277. [PMID: 28424220 DOI: 10.1124/mol.116.107854] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 04/14/2017] [Indexed: 12/11/2022] Open
Abstract
G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs) act in concert to regulate cell growth, proliferation, survival, and migration. Metabotropic GABAB receptor (GABABR) is the GPCR for the main inhibitory neurotransmitter GABA in the central nervous system. Increased expression of GABABR has been detected in human cancer tissues and cancer cell lines, but the role of GABABR in these cells is controversial and the underlying mechanism remains poorly understood. Here, we investigated whether GABABR hijacks RTK signaling to modulate the fates of human prostate cancer cells. RTK array analysis revealed that the GABABR-specific agonist baclofen selectively induced the transactivation of EGFR in PC-3 cells. EGFR transactivation resulted in the activation of ERK1/2 by a mechanism that is dependent on Gi/o protein and that requires matrix metalloproteinase-mediated proligand shedding. Positive allosteric modulators (PAMs) of GABABR, such as CGP7930, rac-BHFF, and GS39783, can function as PAM agonists to induce EGFR transactivation and subsequent ERK1/2 activation. Moreover, both baclofen and CGP7930 promoted cell migration and invasion through EGFR signaling. In summary, our observations demonstrated that GABABR transactivated EGFR in a ligand-dependent mechanism to promote prostate cancer cell migration and invasion, thus providing new insights into developing a novel strategy for prostate cancer treatment by targeting neurotransmitter signaling.
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Affiliation(s)
- Shuai Xia
- Cell Signaling Laboratory, College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Cong He
- Cell Signaling Laboratory, College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Yini Zhu
- Cell Signaling Laboratory, College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Suyun Wang
- Cell Signaling Laboratory, College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Huiping Li
- Cell Signaling Laboratory, College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Zhongling Zhang
- Cell Signaling Laboratory, College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Xinnong Jiang
- Cell Signaling Laboratory, College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Jianfeng Liu
- Cell Signaling Laboratory, College of Life Science and Technology, Collaborative Innovation Center for Genetics and Development, and Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
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18
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Sturchler E, Li X, de Lourdes Ladino M, Kaczanowska K, Cameron M, Griffin PR, Finn MG, Markou A, McDonald P. GABA B receptor allosteric modulators exhibit pathway-dependent and species-selective activity. Pharmacol Res Perspect 2017; 5:e00288. [PMID: 28357120 PMCID: PMC5368958 DOI: 10.1002/prp2.288] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 11/02/2016] [Accepted: 11/30/2016] [Indexed: 01/22/2023] Open
Abstract
Positive modulation of the GABAB receptor (GABABR) represents a potentially useful therapeutic approach for the treatment of nicotine addiction. The positive allosteric modulators (PAMs) of GABABR GS39783 and BHF177 enhance GABA‐stimulated [35S]GTPγS‐binding, and have shown efficacy in a rodent nicotine self‐administration procedure reflecting aspects of nicotine dependence. Interestingly, the structural related analog, NVP998, had no effect on nicotine self‐administration in rats despite demonstrating similar pharmacokinetic properties. Extensive in vitro characterization of GS39783, BHF177, and NVP998 activity on GABABR‐regulated signaling events, including modulation of cAMP, intracellular calcium levels, and ERK activation, revealed that these structurally related molecules display distinct pathway‐specific signaling activities that correlate with the dissimilarities observed in rodent models and may be predictive of in vivo efficacy. Furthermore, these GABABR allosteric modulators exhibit species‐dependent activity. Collectively, these data will be useful in guiding the development of GABABR allosteric modulators that display optimal in vivo efficacy in a preclinical model of nicotine dependence, and will identify those that have the potential to lead to novel antismoking therapies.
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Affiliation(s)
- Emmanuel Sturchler
- Department of Molecular Therapeutics The Scripps Research Institute 130 Scripps way Jupiter Florida 33458
| | - Xia Li
- Department of Psychiatry University of California San Diego 9500 Gilman Drive La Jolla California 92093
| | - Maria de Lourdes Ladino
- Department of Molecular Therapeutics The Scripps Research Institute 130 Scripps way Jupiter Florida 33458; Present address: School of Medicine Vanderbilt University 2215 Garland Ave Nashville Tennessee 37232
| | - Kasia Kaczanowska
- Department of Chemistry The Scripps Research Institute 10550 North Torrey Pines Road La Jolla California 92037; Present address: Department of Chemistry University of California San Diego, 9500 Gilman Drive La Jolla California 92093
| | - Michael Cameron
- Department of Molecular Therapeutics The Scripps Research Institute 130 Scripps way Jupiter Florida 33458
| | - Patrick R Griffin
- Department of Molecular Therapeutics The Scripps Research Institute 130 Scripps way Jupiter Florida 33458
| | - M G Finn
- Department of Chemistry The Scripps Research Institute 10550 North Torrey Pines Road La Jolla California 92037; Present address: Georgia Institute of Technology School of Chemistry and Biochemistry 901 Atlantic Drive Atlanta Georgia 30332
| | - Athina Markou
- Department of Psychiatry University of California San Diego 9500 Gilman Drive La Jolla California 92093
| | - Patricia McDonald
- Department of Molecular Therapeutics The Scripps Research Institute 130 Scripps way Jupiter Florida 33458
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19
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Olianas MC, Dedoni S, Onali P. The GABA B positive allosteric modulators CGP7930 and GS39783 stimulate ERK1/2 signalling in cells lacking functional GABA B receptors. Eur J Pharmacol 2016; 794:135-146. [PMID: 27876620 DOI: 10.1016/j.ejphar.2016.11.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/04/2016] [Accepted: 11/18/2016] [Indexed: 02/03/2023]
Abstract
The present study shows that the GABAB positive allosteric modulators (PAMs) CGP7930 and GS39783 stimulate extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) signalling in cells that do not express functional GABAB receptors. In human SH-SY5Y neuroblastoma cells, CGP7930 and GS39783 induced a time- and concentration-dependent increase in ERK1/2 phosphorylation with potencies similar to those displayed as GABAB PAMs. Conversely, γ-aminobutyric acid and the GABAB receptor agonists (-)baclofen and SKF97541 were completely inactive. CGP7930 and GS39783 enhanced the nuclear localization of phospho-ERK1/2 and CGP7930 promoted the phosphorylation of the transcription factors Elk-1 and CREB. CGP7930-induced ERK1/2 stimulation was insensitive to pertussis toxin, the Gq/11 antagonist YM254890 and the phospholipase C-β inhibitor U-73122, but was completely blocked by the MEK1/2 inhibitor PD98059. Inhibition of insulin-like growth factor-1, platelet--derived growth factor, phosphoinositide 3-kinase and Akt activities potentiated CGP7930-induced ERK1/2 phosphorylation. CGP7930 enhanced the phosphorylation of myristoylated alanine-rich protein kinase C (PKC) substrate and inhibition of PKC attenuated the ERK1/2 stimulation. Over-expression of N17Ras, a dominant negative mutant of c-Ras, or inhibition of c-Raf by GW5074 partially antagonized CGP7930-induced ERK1/2 activation. CGP7930 enhanced the phosphorylation of transforming growth factor-β-activated kinase 1 (TAK-1) and TAK-1 inhibition by 5Z-7-oxozeaenol reduced CGP7930-induced ERK1/2 phosphorylation. CGP7930 activated ERK1/2 in CHO-K1 fibroblasts, which lack endogenous GABAB receptors, but not in HEK-293 cells, indicating that the response displayed cell type specificity. These data demonstrate that CGP7930 and GS39783 can trigger ERK1/2 signalling, a critical modulator of mood and drug addiction, independently of an action on GABAB receptors.
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Affiliation(s)
- Maria C Olianas
- Laboratory of Cellular and Molecular Pharmacology, Section of Neurosciences and Clinical Pharmacology, Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy.
| | - Simona Dedoni
- Laboratory of Cellular and Molecular Pharmacology, Section of Neurosciences and Clinical Pharmacology, Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Pierluigi Onali
- Laboratory of Cellular and Molecular Pharmacology, Section of Neurosciences and Clinical Pharmacology, Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
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20
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Zhang Z, Zhang W, Huang S, Sun Q, Wang Y, Hu Y, Sun N, Zhang Y, Jiang Z, Minato N, Pin JP, Su L, Liu J. GABAB receptor promotes its own surface expression by recruiting a Rap1-dependent signaling cascade. J Cell Sci 2015; 128:2302-13. [DOI: 10.1242/jcs.167056] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 05/05/2015] [Indexed: 12/11/2022] Open
Abstract
ABSTRACT
G-protein-coupled receptors (GPCRs) are key players in cell signaling, and their cell surface expression is tightly regulated. For many GPCRs such as β2-AR (β2-adrenergic receptor), receptor activation leads to downregulation of receptor surface expression, a phenomenon that has been extensively characterized. By contrast, some other GPCRs, such as GABAB receptor, remain relatively stable at the cell surface even after prolonged agonist treatment; however, the underlying mechanisms are unclear. Here, we identify the small GTPase Rap1 as a key regulator for promoting GABAB receptor surface expression. Agonist stimulation of GABAB receptor signals through Gαi/o to inhibit Rap1GAPII (also known as Rap1GAP1b, an isoform of Rap1GAP1), thereby activating Rap1 (which has two isoforms, Rap1a and Rap1b) in cultured cerebellar granule neurons (CGNs). The active form of Rap1 is then recruited to GABAB receptor through physical interactions in CGNs. This Rap1-dependent signaling cascade promotes GABAB receptor surface expression by stimulating receptor recycling. Our results uncover a new mechanism regulating GPCR surface expression and also provide a potential explanation for the slow, long-lasting inhibitory action of GABA neurotransmitter.
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Affiliation(s)
- Zongyong Zhang
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wenhua Zhang
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Siluo Huang
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qian Sun
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yunyun Wang
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yongjian Hu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ninghua Sun
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yilei Zhang
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhihua Jiang
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Nagahiro Minato
- Department of Immunology and Cell Biology, Kyoto University, Kyoto 606-8501, Japan
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, CNRS, UMR 5203, Université Montpellier 1 et 2, Montpellier cedex 5 34094, France
| | - Li Su
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jianfeng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
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21
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GABAB receptor upregulates fragile X mental retardation protein expression in neurons. Sci Rep 2015; 5:10468. [PMID: 26020477 PMCID: PMC4447080 DOI: 10.1038/srep10468] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/15/2015] [Indexed: 12/17/2022] Open
Abstract
Fragile X mental retardation protein (FMRP) is an RNA-binding protein important for the control of translation and synaptic function. The mutation or silencing of FMRP causes Fragile X syndrome (FXS), which leads to intellectual disability and social impairment. γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter of the mammalian central nervous system, and its metabotropic GABAB receptor has been implicated in various mental disorders. The GABAB receptor agonist baclofen has been shown to improve FXS symptoms in a mouse model and in human patients, but the signaling events linking the GABAB receptor and FMRP are unknown. In this study, we found that GABAB receptor activation upregulated cAMP response element binding protein-dependent Fmrp expression in cultured mouse cerebellar granule neurons via two distinct mechanisms: the transactivation of insulin-like growth factor-1 receptor and activation of protein kinase C. In addition, a positive allosteric modulator of the GABAB receptor, CGP7930, stimulated Fmrp expression in neurons. These results suggest a role for GABAB receptor in Fmrp regulation and a potential interest of GABAB receptor signaling in FXS improvement.
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Jin S, Merchant ML, Ritzenthaler JD, McLeish KR, Lederer ED, Torres-Gonzalez E, Fraig M, Barati MT, Lentsch AB, Roman J, Klein JB, Rane MJ. Baclofen, a GABABR agonist, ameliorates immune-complex mediated acute lung injury by modulating pro-inflammatory mediators. PLoS One 2015; 10:e0121637. [PMID: 25848767 PMCID: PMC4388838 DOI: 10.1371/journal.pone.0121637] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 02/12/2015] [Indexed: 11/22/2022] Open
Abstract
Immune-complexes play an important role in the inflammatory diseases of the lung. Neutrophil activation mediates immune-complex (IC) deposition-induced acute lung injury (ALI). Components of gamma amino butyric acid (GABA) signaling, including GABA B receptor 2 (GABABR2), GAD65/67 and the GABA transporter, are present in the lungs and in the neutrophils. However, the role of pulmonary GABABR activation in the context of neutrophil-mediated ALI has not been determined. Thus, the objective of the current study was to determine whether administration of a GABABR agonist, baclofen would ameliorate or exacerbate ALI. We hypothesized that baclofen would regulate IC-induced ALI by preserving pulmonary GABABR expression. Rats were subjected to sham injury or IC-induced ALI and two hours later rats were treated intratracheally with saline or 1 mg/kg baclofen for 2 additional hours and sacrificed. ALI was assessed by vascular leakage, histology, TUNEL, and lung caspase-3 cleavage. ALI increased total protein, tumor necrosis factor α (TNF-α and interleukin-1 receptor associated protein (IL-1R AcP), in the bronchoalveolar lavage fluid (BALF). Moreover, ALI decreased lung GABABR2 expression, increased phospho-p38 MAPK, promoted IκB degradation and increased neutrophil influx in the lung. Administration of baclofen, after initiation of ALI, restored GABABR expression, which was inhibited in the presence of a GABABR antagonist, CGP52432. Baclofen administration activated pulmonary phospho-ERK and inhibited p38 MAPK phosphorylation and IκB degradation. Additionally, baclofen significantly inhibited pro-inflammatory TNF-α and IL-1βAcP release and promoted BAL neutrophil apoptosis. Protective effects of baclofen treatment on ALI were possibly mediated by inhibition of TNF-α- and IL-1β-mediated inflammatory signaling. Interestingly, GABABR2 expression was regulated in the type II pneumocytes in lung tissue sections from lung injured patients, further suggesting a physiological role for GABABR2 in the repair process of lung damage. GABABR2 agonists may play a potential therapeutic role in ALI.
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Affiliation(s)
- Shunying Jin
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Michael L. Merchant
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Jeffrey D. Ritzenthaler
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Kenneth R. McLeish
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America
- Robley Rex VA Medical Center, Zorn Avenue, Louisville, Kentucky, United States of America
| | - Eleanor D. Lederer
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
- Robley Rex VA Medical Center, Zorn Avenue, Louisville, Kentucky, United States of America
- Department of Physiology, University of Louisville, Louisville, Kentucky, United States of America
| | - Edilson Torres-Gonzalez
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Mostafa Fraig
- Department of Pathology, University of Louisville, Louisville, Kentucky, United States of America
| | - Michelle T. Barati
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Alex B. Lentsch
- Department of Surgery, University of Cincinnati, Cincinnati, OH, United States of America
| | - Jesse Roman
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
- Robley Rex VA Medical Center, Zorn Avenue, Louisville, Kentucky, United States of America
| | - Jon B. Klein
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America
- Robley Rex VA Medical Center, Zorn Avenue, Louisville, Kentucky, United States of America
| | - Madhavi J. Rane
- Department of Medicine, University of Louisville, Louisville, Kentucky, United States of America
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America
- * E-mail:
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23
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Cytoskeletal rearrangement and Src and PI-3K-dependent Akt activation control GABA(B)R-mediated chemotaxis. Cell Signal 2015; 27:1178-1185. [PMID: 25725285 DOI: 10.1016/j.cellsig.2015.02.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 02/01/2015] [Accepted: 02/15/2015] [Indexed: 01/13/2023]
Abstract
The γ-amino butyric acid (GABA) type B receptors (GABA(B)R) function as chemoattractant receptors in response to GABA(B)R agonists in human neutrophils. The goal of this study was to define signaling mechanisms regulating GABA(B)R-mediated chemotaxis and cytoskeletal rearrangement. In a proteomic study we identified serine/threonine kinase Akt, tyrosine kinases Src and Pyk2, microtubule regulator kinesin and microtubule affinity-regulating kinase (MARK) co-immunoprecipitating with GABA(B)R. To define the contributions of these candidate signaling events in GABA(B)R-mediated chemotaxis, we used rat basophilic leukemic cells (RBL-2H3 cells) stably transfected with human GABA(B1b) and GABA(B2) receptors. The GABA(B)R agonist baclofen induced Akt phosphorylation and chemotaxis by binding to its specific GABA(B)R since pretreatment of cells with CGP52432, a GABA(B)R antagonist, blocked such effects. Moreover, baclofen induced Akt phosphorylation was shown to be dependent upon PI-3K and Src kinases. Baclofen failed to stimulate actin polymerization in suspended RBL cells unless exposed to a baclofen gradient. However, baclofen stimulated both actin and tubulin polymerization in adherent RBL-GABA(B)R cells. Blockade of actin and tubulin polymerization by treatment of cells with cytochalasin D or nocodazole respectively, abolished baclofen-mediated chemotaxis. Furthermore, baclofen stimulated Pyk2 and STAT3 phosphorylation, both known regulators of cell migration. In conclusion, GABA(B)R stimulation promotes chemotaxis in RBL cells which is dependent on signaling via PI3-K/Akt, Src kinases and on rearrangement of both microtubules and actin cytoskeleton. These data define mechanisms of GABA(B)R-mediated chemotaxis which may potentially be used to therapeutically regulate cellular response to injury and disease.
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Chen LH, Sun B, Zhang Y, Xu TJ, Xia ZX, Liu JF, Nan FJ. Discovery of a Negative Allosteric Modulator of GABAB Receptors. ACS Med Chem Lett 2014; 5:742-7. [PMID: 25050158 PMCID: PMC4094264 DOI: 10.1021/ml500162z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Accepted: 05/27/2014] [Indexed: 12/11/2022] Open
Abstract
Initialized from the scaffold of CGP7930, an allosteric agonist of GABAB receptors, a series of noncompetitive antagonists were discovered. Among these compounds, compounds 3, 6, and 14 decreased agonist GABA-induced maximal effect of IP3 production in HEK293 cells overexpressing GABAB receptors and Gqi9 proteins without changing the EC50. Compounds 3, 6, and 14 not only inhibited agonist baclofen-induced ERK1/2 phosphorylation but also blocked CGP7930-induced ERK1/2 phosphorylation in HEK293 cells overexpressing GABAB receptors. The results suggested that compounds 3, 6, and 14 are negative allosteric modulators of GABAB receptors. The representative compound 14 decreased GABA-induced IP3 production with IC50 of 37.9 μM and had no effect on other GPCR Class C members such as mGluR1, mGluR2, and mGluR5. Finally, we showed that compound 14 did not bind to the orthosteric binding sites of GABAB receptors, demonstrating that compound 14 negatively modulated GABAB receptors activity as a negative allosteric modulator.
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Affiliation(s)
- Lin-Hai Chen
- National
Center for Drug Screening, State Key Laboratory of Drug Research,
Shanghai Institute of Materia Medica, Chinese
Academy of Sciences, Shanghai, China
| | - Bing Sun
- Cellular
Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry
of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yang Zhang
- Cellular
Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry
of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Tong-Jie Xu
- Cellular
Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry
of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhi-Xiong Xia
- Cellular
Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry
of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jian-Feng Liu
- Cellular
Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry
of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Fa-Jun Nan
- National
Center for Drug Screening, State Key Laboratory of Drug Research,
Shanghai Institute of Materia Medica, Chinese
Academy of Sciences, Shanghai, China
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25
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Xu F, Zhao H, Feng X, Chen L, Chen D, Zhang Y, Nan F, Liu J, Liu BF. Single-cell chemical proteomics with an activity-based probe: identification of low-copy membrane proteins on primary neurons. Angew Chem Int Ed Engl 2014; 53:6730-3. [PMID: 24850238 DOI: 10.1002/anie.201402363] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/24/2014] [Indexed: 11/08/2022]
Abstract
We propose a novel single-cell chemical proteomics (SCCP) strategy to profile low-abundance membrane proteins in single cells. In this approach, the membrane protein GB1 and its splicing variants were targeted on cultured cell lines and primary neurons using a specifically designed activity-based probe. The functionally labeled single cells were encapsulated in individual buffer droplets on a PDMS microwell array, and were further picked up one at a time and loaded into a capillary electrophoresis system for cell lysis, separation, and laser-induced fluorescence detection of the targeted proteins. The results revealed the expression of GB1 splicing variants in HEK and MEF cells, which was previously only suggested at the transcriptional level. We further applied this method to investigate single primary cells and observed significant heterogeneity among individual mouse cerebellar granule neurons. Interference experiments with GB1 antagonist and agonist validated this observation.
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Affiliation(s)
- Fei Xu
- Wuhan National Laboratory for Optoelectronics-, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)
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26
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Xu F, Zhao H, Feng X, Chen L, Chen D, Zhang Y, Nan F, Liu J, Liu BF. Single-Cell Chemical Proteomics with an Activity-Based Probe: Identification of Low-Copy Membrane Proteins on Primary Neurons. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201402363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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27
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Maier PJ, Zemoura K, Acuña MA, Yévenes GE, Zeilhofer HU, Benke D. Ischemia-like oxygen and glucose deprivation mediates down-regulation of cell surface γ-aminobutyric acidB receptors via the endoplasmic reticulum (ER) stress-induced transcription factor CCAAT/enhancer-binding protein (C/EBP)-homologous protein (CHOP). J Biol Chem 2014; 289:12896-907. [PMID: 24668805 DOI: 10.1074/jbc.m114.550517] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cerebral ischemia frequently leads to long-term disability and death. Excitotoxicity is believed to be the main cause for ischemia-induced neuronal death. Although a role of glutamate receptors in this process has been firmly established, the contribution of metabotropic GABAB receptors, which control excitatory neurotransmission, is less clear. A prominent characteristic of ischemic insults is endoplasmic reticulum (ER) stress associated with the up-regulation of the transcription factor CCAAT/enhancer-binding protein-homologous protein (CHOP). After inducing ER stress in cultured cortical neurons by sustained Ca(2+) release from intracellular stores or by a brief episode of oxygen and glucose deprivation (in vitro model of cerebral ischemia), we observed an increased expression of CHOP accompanied by a strong reduction of cell surface GABAB receptors. Our results indicate that down-regulation of cell surface GABAB receptors is caused by the interaction of the receptors with CHOP in the ER. Binding of CHOP prevented heterodimerization of the receptor subunits GABAB1 and GABAB2 and subsequent forward trafficking of the receptors to the cell surface. The reduced level of cell surface receptors diminished GABAB receptor signaling and, thus, neuronal inhibition. These findings indicate that ischemia-mediated up-regulation of CHOP down-regulates cell surface GABAB receptors by preventing their trafficking from the ER to the plasma membrane. This mechanism leads to diminished neuronal inhibition and may contribute to excitotoxicity in cerebral ischemia.
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Affiliation(s)
- Patrick J Maier
- From the Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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28
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Zhang D, Li X, Yao Z, Wei C, Ning N, Li J. GABAergic signaling facilitates breast cancer metastasis by promoting ERK1/2-dependent phosphorylation. Cancer Lett 2014; 348:100-8. [PMID: 24657659 DOI: 10.1016/j.canlet.2014.03.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 01/23/2014] [Accepted: 03/07/2014] [Indexed: 12/31/2022]
Abstract
The present study aims to determine the role of γ-aminobutyric acid (GABA) signaling molecules in breast cancer metastasis. Our results reveal that GABAergic system exists in breast cancer cells. Both the GABA synthetic enzyme. (GAD65/67) and GABAB receptor are expressed in 4T1 mouse breast cancer cells, MCF-7 human breast cancer cells and human breast cancer tissue. Baclofen, a GABABR agonist, significantly promoted 4T1 cells invasion and migration in vitro and metastasis in vivo, an event that was attenuated by GABABR antagonist CGP55845. Baclofen-induced breast cancer metastasis was mediated by ERK1/2 pathway.
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Affiliation(s)
- Depu Zhang
- Department of Physiology, School of Medicine, Shandong University, Jinan 250012, China
| | - Xiaowei Li
- Department of Physiology, School of Medicine, Shandong University, Jinan 250012, China
| | - Ziming Yao
- Department of Physiology, School of Medicine, Shandong University, Jinan 250012, China
| | - Chuanfei Wei
- Department of Physiology, School of Medicine, Shandong University, Jinan 250012, China
| | - Nannan Ning
- Department of Physiology, School of Medicine, Shandong University, Jinan 250012, China
| | - Jingxin Li
- Department of Physiology, School of Medicine, Shandong University, Jinan 250012, China.
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29
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Xu C, Zhang W, Rondard P, Pin JP, Liu J. Complex GABAB receptor complexes: how to generate multiple functionally distinct units from a single receptor. Front Pharmacol 2014; 5:12. [PMID: 24575041 PMCID: PMC3920572 DOI: 10.3389/fphar.2014.00012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/22/2014] [Indexed: 01/05/2023] Open
Abstract
The main inhibitory neurotransmitter, GABA, acts on both ligand-gated and G protein-coupled receptors, the GABAA/C and GABAB receptors, respectively. The later play important roles in modulating many synapses, both at the pre- and post-synaptic levels, and are then still considered as interesting targets to treat a number of brain diseases, including addiction. For many years, several subtypes of GABAB receptors were expected, but cloning revealed only two genes that work in concert to generate a single type of GABAB receptor composed of two subunits. Here we will show that the signaling complexity of this unit receptor type can be largely increased through various ways, including receptor stoichiometry, subunit isoforms, cell-surface expression and localization, crosstalk with other receptors, or interacting proteins. These recent data revealed how complexity of a receptor unit can be increased, observation that certainly are not unique to the GABAB receptor.
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Affiliation(s)
- Chanjuan Xu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology Wuhan, China
| | - Wenhua Zhang
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology Wuhan, China
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Universités de Montpellier I & II Montpellier, France
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Universités de Montpellier I & II Montpellier, France
| | - Jianfeng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology Wuhan, China
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30
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Yun Y, Yao G, Yue H, Guo L, Qin G, Li G, Sang N. SO(2) inhalation causes synaptic injury in rat hippocampus via its derivatives in vivo. CHEMOSPHERE 2013; 93:2426-2432. [PMID: 24099899 DOI: 10.1016/j.chemosphere.2013.08.063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 08/14/2013] [Accepted: 08/16/2013] [Indexed: 06/02/2023]
Abstract
SO(2) remains a common air pollutant, almost half of the world's population uses coal and biomass fuels for domestic energy. Limited evidence suggests that exposure to SO(2) may be associated with neurotoxicity and increased risk of hospitalization and mortality of many brain disorders. However, our understanding of the mechanisms by which SO(2) causes harmful insults on neurons remains elusive. To explore the molecular mechanism of SO(2)-induced neurotoxic effects in hippocampal neurons, we evaluated the synaptic plasticity in rat hippocampus after exposure to SO(2)at various concentrations (3.5 and 7 mg m(-3), 6 h d(-1), for 90 d) in vivo, and in primary cultured hippocampal neurons (DIV7 and DIV14) after the treatment of SO2 derivatives in vitro. The results showed that SYP, PSD-95, NR-2B, p-ERK1/2 and p-CREB were consistently inhibited by SO(2)/SO(2) derivatives in more mature hippocampal neurons in vivo and in vitro, while the effects were opposite in young hippocampal neurons. Our results indicated that in young neurons, SO(2) exposure produced neuronal insult is similar to ischemic injury; while in more mature neurons, SO(2) exposure induced synaptic dysfunctions might participate in cognitive impairment. The results implied that SO(2) inhalation could cause different neuronal injury during brain development, and suggested that the molecular mechanisms might be involved in the changes of synaptic plasticity.
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Affiliation(s)
- Yang Yun
- College of Environment and Resource, Shanxi University, Taiyuan, Shanxi 030006, PR China
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31
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O'Malley MW, Datta S. REM Sleep Regulating Mechanisms in the Cholinergic Cell Compartment of the Brainstem. ACTA ACUST UNITED AC 2013; 8:58-66. [PMID: 25400382 DOI: 10.5958/j.0974-0155.8.2.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Rapid eye movement (REM) sleep is a highly evolved yet paradoxical behavioral state (highly activated brain in a paralyzed body) in mammalian species. Since the discovery of REM sleep and its physiological distinction from other sleep states1, a vast number of studies in neurosciences have been dedicated toward understanding the mechanisms and functions of this behavioral state. Collectively, studies have shown that each of the physiological events that characterize the behavioral state of REM sleep is executed by distinct cell groups located in the brainstem. These cell groups are discrete components of a widely distributed network, rather than a single REM sleep center. The final activity within each of these executive cell groups is controlled by the ratio of cholinergic neurotransmission emanating from the pedunculopontine tegmentum (PPT) to aminergic neurotransmission emanating from the locus coeruleus (LC) and raphe nucleus (RN). In this review, we summarize the most recent findings on the cellular and molecular mechanisms in the PPT cholinergic cell compartment that underlie the regulation of REM sleep. This up-to-date review should allow clinicians and researchers to better understand the effects of drugs and neurologic disease on REM sleep.
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Affiliation(s)
- Matthew W O'Malley
- Laboratory of Sleep and Cognitive Neuroscience, Boston University School of Medicine, 85 East Newton Street, Suite: M-902, Boston, Massachusetts 02118 ; Department of Psychiatry, Boston University School of Medicine, 85 East Newton Street, Suite: M-902, Boston, Massachusetts 02118
| | - Subimal Datta
- Laboratory of Sleep and Cognitive Neuroscience, Boston University School of Medicine, 85 East Newton Street, Suite: M-902, Boston, Massachusetts 02118 ; Department of Psychiatry, Boston University School of Medicine, 85 East Newton Street, Suite: M-902, Boston, Massachusetts 02118 ; Department of Neurology, Boston University School of Medicine, 85 East Newton Street, Suite: M-902, Boston, Massachusetts 02118
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Di Giorgio NP, Catalano PN, López PV, González B, Semaan SJ, López GC, Kauffman AS, Rulli SB, Somoza GM, Bettler B, Libertun C, Lux-Lantos VA. Lack of functional GABAB receptors alters Kiss1 , Gnrh1 and Gad1 mRNA expression in the medial basal hypothalamus at postnatal day 4. Neuroendocrinology 2013; 98:212-23. [PMID: 24080944 PMCID: PMC3915412 DOI: 10.1159/000355631] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 09/10/2013] [Indexed: 01/01/2023]
Abstract
BACKGROUND/AIMS Adult mice lacking functional GABAB receptors (GABAB1KO) show altered Gnrh1 and Gad1 expressions in the preoptic area-anterior hypothalamus (POA-AH) and females display disruption of cyclicity and fertility. Here we addressed whether sexual differentiation of the brain and the proper wiring of the GnRH and kisspeptin systems were already disturbed in postnatal day 4 (PND4) GABAB1KO mice. METHODS PND4 wild-type (WT) and GABAB1KO mice of both sexes were sacrificed; tissues were collected to determine mRNA expression (qPCR), amino acids (HPLC), and hormones (RIA and/or IHC). RESULTS GnRH neuron number (IHC) did not differ among groups in olfactory bulbs or OVLT-POA. Gnrh1 mRNA (qPCR) in POA-AH was similar among groups. Gnrh1 mRNA in medial basal hypothalamus (MBH) was similar in WTs but was increased in GABAB1KO females compared to GABAB1KO males. Hypothalamic GnRH (RIA) was sexually different in WTs (males > females), but this sex difference was lost in GABAB1KOs; the same pattern was observed when analyzing only the MBH, but not in the POA-AH. Arcuate nucleus Kiss1 mRNA (micropunch-qPCR) was higher in WT females than in WT males and GABAB1KO females. Gad1 mRNA in MBH was increased in GABAB1KO females compared to GABAB1KO males. Serum LH and gonadal estradiol content were also increased in GABAB1KOs. CONCLUSION We demonstrate that GABABRs participate in the sexual differentiation of the ARC/MBH, because sex differences in several reproductive genes, such as Gad1, Kiss1 and Gnrh1, are critically disturbed in GABAB1KO mice at PND4, probably altering the organization and development of neural circuits governing the reproductive axis.
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MESH Headings
- Animals
- Animals, Newborn
- Arcuate Nucleus of Hypothalamus/growth & development
- Arcuate Nucleus of Hypothalamus/metabolism
- Female
- Gene Expression Regulation, Developmental
- Glutamate Decarboxylase/deficiency
- Glutamate Decarboxylase/genetics
- Gonadotropin-Releasing Hormone/deficiency
- Gonadotropin-Releasing Hormone/genetics
- Hypothalamus, Middle/growth & development
- Hypothalamus, Middle/metabolism
- Kisspeptins/deficiency
- Kisspeptins/genetics
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- Protein Precursors/deficiency
- Protein Precursors/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, GABA-B/deficiency
- Receptors, GABA-B/genetics
- Sex Differentiation/genetics
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Affiliation(s)
- Noelia P Di Giorgio
- Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
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Baloucoune GA, Chun L, Zhang W, Xu C, Huang S, Sun Q, Wang Y, Tu H, Liu J. GABAB receptor subunit GB1 at the cell surface independently activates ERK1/2 through IGF-1R transactivation. PLoS One 2012; 7:e39698. [PMID: 22761875 PMCID: PMC3386256 DOI: 10.1371/journal.pone.0039698] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 05/29/2012] [Indexed: 12/24/2022] Open
Abstract
Background Functional GABAB receptor is believed to require hetero-dimerization between GABAB1 (GB1) and GABAB2 (GB2) subunits. The GB1 extracellular domain is required for ligand binding, and the GB2 trans-membrane domain is responsible for coupling to G proteins. Atypical GABAB receptor responses observed in GB2-deficient mice suggested that GB1 may have activity in the absence of GB2. However the underlying mechanisms remain poorly characterized. Methodology/Principal Findings Here, by using cells overexpressing a GB1 mutant (GB1asa) with the ability to translocate to the cell surface in the absence of GB2, we show that GABAB receptor agonists, such as GABA and Baclofen, can induce ERK1/2 phosphorylation in the absence of GB2. Furthermore, we demonstrate that GB1asa induces ERK1/2 phosphorylation through Gi/o proteins and PLC dependent IGF-1R transactivation. Conclusions/Significance Our data suggest that GB1 may form a functional receptor at the cell surface in the absence of GB2.
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Affiliation(s)
- Guillaume A. Baloucoune
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Lei Chun
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Wenhua Zhang
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chanjuan Xu
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Siluo Huang
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Qian Sun
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yunyun Wang
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Haijun Tu
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jianfeng Liu
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- * E-mail:
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An activity-based probe reveals dynamic protein-protein interactions mediating IGF-1R transactivation by the GABA(B) receptor. Biochem J 2012; 443:627-34. [PMID: 22394253 DOI: 10.1042/bj20120188] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Many GPCRs (G-protein-coupled receptors) can activate RTKs (receptor tyrosine kinases) in the absence of RTK ligands, a phenomenon called transactivation. However, the underlying molecular mechanisms remain undefined. In the present study we investigate the molecular basis of GABA(B) (γ-aminobutyric acid B) receptor-mediated transactivation of IGF-1R (insulin-like growth factor type I receptor) in primary neurons. We take a chemical biology approach by developing an activity-based probe targeting the GABA(B) receptor. This probe enables us first to lock the GABA(B) receptor in an inactive state and then activate it with a positive allosteric modulator, thereby permitting monitoring of the dynamic of the protein complex associated with IGF-1R transactivation. We find that activation of the GABA(B) receptor induces a dynamic assembly and disassembly of a protein complex, including both receptors and their downstream effectors. FAK (focal adhesion kinase), a non-RTK, plays a key role in co-ordinating this dynamic process. Importantly, this dynamic of the GABA(B) receptor-associated complex is critical for transactivation and transactivation-dependent neuronal survival. The present study has identified an important mechanism underlying GPCR transactivation of RTKs, which was enabled by a new chemical biology tool generally applicable for dissecting GPCR signalling.
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Abstract
The G-protein-coupled receptors (GPCRs) are one of the largest super families of cell-surface receptors and play crucial roles in virtually every organ system. One particular family of GPCRs, the class C GPCRs, is distinguished by a characteristically large extracellular domain and constitutive dimerization. The structure and activation mechanism of this family result in potentially unique ligand recognition sites, thereby offering a variety of possibilities by which receptor activity might be modulated using novel compounds. In the present article, we aim to provide an overview of the exact sites and structural features involved in ligand recognition of the class C GPCRs. Furthermore, we demonstrate the precise steps that occur during the receptor activation process, which underlie the possibilities by which receptor function may be altered by different approaches. Finally, we use four typical family members to illustrate orthosteric and allosteric sites with representative ligands and their corresponding therapeutic potential.
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Im BH, Rhim H. GABA(B) receptor-mediated ERK1/2 phosphorylation via a direct interaction with Ca(V)1.3 channels. Neurosci Lett 2012; 513:89-94. [PMID: 22366257 DOI: 10.1016/j.neulet.2012.02.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 02/06/2012] [Indexed: 01/02/2023]
Abstract
Neuronal L-type Ca(2+) channels play pivotal roles in regulating gene expression, cell survival, and synaptic plasticity. The Ca(V)1.2 and Ca(V)1.3 channels are 2 main subtypes of neuronal L-type Ca(2+) channels. However, the specific roles of Ca(V)1.2 and Ca(V)1.3 in L-type Ca(2+) channel-mediated neuronal responses and their cellular mechanisms are poorly elucidated. On the basis of our previous study demonstrating a physical interaction between the Ca(V)1.3 channel and GABA(B) receptor (GABA(B)R), we further examined the involvement of Ca(V)1.2 and Ca(V)1.3 in the GABA(B)R-mediated activation of ERK(1/2), a kinase involved in both CREB activation and synaptic plasticity. After confirming the involvement of L-type Ca(2+) channels in baclofen-induced ERK(1/2) phosphorylation, we examined a specific role of Ca(V)1.2 and Ca(V)1.3 channels in the baclofen effect. Using siRNA-mediated silencing of Ca(V)1.2 or Ca(V)1.3 messenger, we determined the relevance of each channel subtype to baclofen-induced ERK(1/2) phosphorylation in a mouse hippocampal cell line (HT-22) and primary cultured rat neurons. In the detailed characterization of each subtype using HEK293 cells transfected with Ca(V)1.2 or Ca(V)1.3, we found that GABA(B)R can increase ERK(1/2) phosphorylation and Ca(V)1.3 channel activity through direct interaction with Ca(V)1.3 channels. These results suggest a functional interaction between Ca(V)1.3 and GABA(B)R and important implications of Ca(V)1.3/GABA(B)R clusters for translating synaptic activity into gene expression alterations.
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Affiliation(s)
- Bo-Hye Im
- Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea
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Jiang X, Su L, Zhang Q, He C, Zhang Z, Yi P, Liu J. GABAB receptor complex as a potential target for tumor therapy. J Histochem Cytochem 2012; 60:269-79. [PMID: 22266766 DOI: 10.1369/0022155412438105] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the vertebrate central nervous system. Metabotropic GABA(B) receptors are heterodimeric G-protein-coupled receptors (GPCRs) consisting of GABA(B1) and GABA(B2) subunits. The intracellular C-terminal domains of GABA(B) receptors are involved in heterodimerization, oligomerization, and association with other proteins, which results in a large receptor complex. Multiple splice variants of the GABA(B1) subunit have been identified in which GABA(B1a) and GABA(B1b) are the most abundant isoforms in the nervous system. Isoforms GABA(B1c) through GABA(B1n) are minor isoforms and are detectable only at mRNA levels. Some of the minor isoforms have been detected in peripheral tissues and encode putative soluble proteins with C-terminal truncations. Interestingly, increased expression of GABA(B) receptors has been detected in several human cancer cells and tissues. Moreover, GABA(B) receptor agonist baclofen inhibited tumor growth in rat models. GABA(B) receptor activation not only induces suppressing the proliferation and migration of various human tumor cells but also results in inactivation of CREB (cAMP-responsive element binding protein) and ERK in tumor cells. Their structural complexity makes it possible to disrupt the functions of GABA(B) receptors in various ways, raising GABA(B) receptor diversity as a potential therapeutic target in some human cancers.
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Affiliation(s)
- Xinnong Jiang
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P. R. China.
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Hensler JG, Advani T, Burke TF, Cheng K, Rice KC, Koek W. GABAB receptor-positive modulators: brain region-dependent effects. J Pharmacol Exp Ther 2011; 340:19-26. [PMID: 21954301 DOI: 10.1124/jpet.111.186577] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
This study examined the positive modulatory properties of 2,6-di-tert-butyl-4-(3-hydroxy-2,2-dimethyl-propyl)-phenol (CGP7930) and (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF) at γ-aminobutyric acid B (GABA(B)) receptors in different brain regions. Using quantitative autoradiography, we measured GABA(B) receptor-stimulated binding of guanosine 5'-O-(3-[³⁵S]thiotriphosphate) ([³⁵S]GTPγS) to G proteins in medial prefrontal cortex (mPFC), hippocampus, and cerebellum. CGP7930 and rac-BHFF enhanced baclofen-stimulated [³⁵S]GTPγS binding similarly in mPFC and hippocampus, but were more effective in cerebellum. CGP7930 (100 μM) increased [³⁵S]GTPγS binding stimulated by baclofen (30 μM) from 29 to 241% above basal in mPFC and from 13 to 1530% above basal in cerebellum. Likewise, rac-BHFF (10 μM) increased baclofen-stimulated [³⁵S]GTPγS binding more in cerebellum (from 13 to 1778% above basal) than in mPFC (from 29 to 514% above basal). rac-BHFF (10 μM) in combination with γ-hydroxybutyrate (20 mM) increased [³⁵S]GTPγS binding in cerebellum but not in mPFC. rac-BHFF also enhanced the effects of 3-aminopropyl(diethoxymethyl)phosphinic acid (CGP35348). Consistent with its partial agonist properties, CGP35348 stimulated [³⁵S]GTPγS binding in mPFC when given alone (to 18% above basal), but less extensively than baclofen (140% above basal), and antagonized baclofen when given together. CGP35348 (1 mM) in combination with rac-BHFF (100 μM) produced an increase in [³⁵S]GTPγS binding that was larger in cerebellum (from 61 to 1260% above basal) than in mPFC (from 18 to 118% above basal). Taken together, the results show that GABA(B) receptor-positive modulators enhance [³⁵S]GTPγS binding stimulated by GABA(B) receptor agonists in a brain region-dependent manner. This regionally selective enhancement is further evidence of pharmacologically distinct GABA(B) receptor populations, possibly allowing for more selective therapeutic targeting of the GABA(B) system.
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Affiliation(s)
- Julie G Hensler
- Department of Pharmacology, MC 7764, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
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Contribution of metabotropic GABA(B) receptors to neuronal network construction. Pharmacol Ther 2011; 132:170-9. [PMID: 21718720 DOI: 10.1016/j.pharmthera.2011.06.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 06/08/2011] [Indexed: 01/05/2023]
Abstract
In the 1980s, Bowery and colleagues discovered the presence of a novel, bicuculline-resistant and baclofen-sensitive type of GABA receptor on peripheral nerve terminals, the GABA(B) receptor. Since this pioneering work, GABA(B) receptors have been identified in the Central Nervous System (CNS), where they provide an important inhibitory control of postsynaptic excitability and presynaptic transmitter release. GABA(B) receptors have been implicated in a number of important processes in the adult brain such as the regulation of synaptic plasticity and modulation of rhythmic activity. As a result of these studies, several potential therapeutic applications of GABA(B) receptor ligands have been identified. Recent advances have further shown that GABA(B) receptors play more than a classical inhibitory role in adult neurotransmission, and can in fact function as an important developmental signal early in life. Here we summarize current knowledge on the contribution of GABA(B) receptors to the construction and function of developing neuronal networks.
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Stern CM, Luoma JI, Meitzen J, Mermelstein PG. Corticotropin releasing factor-induced CREB activation in striatal neurons occurs via a novel Gβγ signaling pathway. PLoS One 2011; 6:e18114. [PMID: 21448293 PMCID: PMC3063246 DOI: 10.1371/journal.pone.0018114] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 02/25/2011] [Indexed: 02/06/2023] Open
Abstract
The peptide corticotropin-releasing factor (CRF) was initially identified as a critical component of the stress response. CRF exerts its cellular effects by binding to one of two cognate G-protein coupled receptors (GPCRs), CRF receptor 1 (CRFR1) or 2 (CRFR2). While these GPCRs were originally characterized as being coupled to Gα(s), leading to downstream activation of adenylyl cyclase (AC) and subsequent increases in cAMP, it has since become clear that CRFRs couple to and activate numerous other downstream signaling cascades. In addition, CRF signaling influences the activity of many diverse brain regions, affecting a variety of behaviors. One of these regions is the striatum, including the nucleus accumbens (NAc). CRF exerts profound effects on striatal-dependent behaviors such as drug addiction, pair-bonding, and natural reward. Recent data indicate that at least some of these behaviors regulated by CRF are mediated through CRF activation of the transcription factor CREB. Thus, we aimed to elucidate the signaling pathway by which CRF activates CREB in striatal neurons. Here we describe a novel neuronal signaling pathway whereby CRF leads to a rapid Gβγ- and MEK-dependent increase in CREB phosphorylation. These data are the first descriptions of CRF leading to activation of a Gβγ-dependent signaling pathway in neurons, as well as the first description of Gβγ activation leading to downstream CREB phosphorylation in any cellular system. Additionally, these data provide additional insight into the mechanisms by which CRF can regulate neuronal function.
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Affiliation(s)
- Christopher M. Stern
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Jessie I. Luoma
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - John Meitzen
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Paul G. Mermelstein
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States of America
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Desarnaud F, Macone BW, Datta S. Activation of extracellular signal-regulated kinase signaling in the pedunculopontine tegmental cells is involved in the maintenance of sleep in rats. J Neurochem 2011; 116:577-87. [PMID: 21166678 DOI: 10.1111/j.1471-4159.2010.07146.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Considerable evidence suggests that receptor-mediated excitation and inhibition of brainstem pedunculopontine tegmental (PPT) neurons are critically involved in the regulation of sleep-wake states. However, the molecular mechanisms operating within the PPT-controlling sleep-wake states remain relatively unknown. This study was designed to examine sleep-wake state-associated extracellular-signal-regulated kinase 1 and 2 (ERK1/2) transduction changes in the PPT of freely moving rats. The results of this study demonstrate that the levels of ERK1/2 expression, phosphorylation, and activity in the PPT increased with increased amount of time spent in sleep. The sleep-associated increases in ERK1/2 expression, phosphorylation, and activity were not observed in the cortex, or in the immediately adjacent medial pontine reticular formation. The results of regression analyses revealed significant positive relationships between the levels of ERK1/2 expression, phosphorylation, and activity in the PPT and amounts of time spent in slow-wave sleep, rapid eye movement sleep, and total sleep. Additionally, these regression analyses revealed significant negative relationships between the levels of ERK1/2 expression, phosphorylation, and activity in the PPT and amounts of time spent in wakefulness. Collectively, these results, for the first time, suggest that the increased ERK1/2 signaling in the PPT is associated with maintenance of sleep via suppression of wakefulness.
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Affiliation(s)
- Frank Desarnaud
- Department of Laboratory of Sleep and Cognitive Neuroscience, Boston University School of Medicine, Boston, Massachusetts, USA
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Urwyler S. Allosteric modulation of family C G-protein-coupled receptors: from molecular insights to therapeutic perspectives. Pharmacol Rev 2011; 63:59-126. [PMID: 21228259 DOI: 10.1124/pr.109.002501] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Allosteric receptor modulation is an attractive concept in drug targeting because it offers important potential advantages over conventional orthosteric agonism or antagonism. Allosteric ligands modulate receptor function by binding to a site distinct from the recognition site for the endogenous agonist. They often have no effect on their own and therefore act only in conjunction with physiological receptor activation. This article reviews the current status of allosteric modulation at family C G-protein coupled receptors in the light of their specific structural features on the one hand and current concepts in receptor theory on the other hand. Family C G-protein-coupled receptors are characterized by a large extracellular domain containing the orthosteric agonist binding site known as the "venus flytrap module" because of its bilobal structure and the dynamics of its activation mechanism. Mutational analysis and chimeric constructs have revealed that allosteric modulators of the calcium-sensing, metabotropic glutamate and GABA(B) receptors bind to the seven transmembrane domain, through which they modify signal transduction after receptor activation. This is in contrast to taste-enhancing molecules, which bind to different parts of sweet and umami receptors. The complexity of interactions between orthosteric and allosteric ligands is revealed by a number of adequate biochemical and electrophysiological assay systems. Many allosteric family C GPCR modulators show in vivo efficacy in behavioral models for a variety of clinical indications. The positive allosteric calcium sensing receptor modulator cinacalcet is the first drug of this type to enter the market and therefore provides proof of principle in humans.
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Affiliation(s)
- Stephan Urwyler
- Department of Chemistry and Biochemistry, University of Berne, P/A Weissensteinweg 3, CH-3303 Jegenstorf, Berne, Switzerland.
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Abstract
Circadian clocks control a variety of neuronal, behavioral and physiological responses, via transcriptional regulation of an appreciable portion of the genome. We describe the complex communication network between the brain-specific central clock and the tissue-specific peripheral clocks that serve to synchronize the organism to both external and internal demands. In addition, we discuss and speculate on how epigenetic processes are involved in creating transcriptional environments that are permissive to tissue-specific gene expression programs, which work in concert with the circadian machinery. Accumulating data show that chromatin remodeling events may be critical for providing specificity and plasticity in circadian regulation, and metabolic cues may be involved in directing such epigenetic events. A detailed understanding of the communication cues between the central and peripheral clocks is crucial for a more complete understanding of the circadian system and the several levels of control that are implicated in maintaining biological timekeeping.
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Padgett CL, Slesinger PA. GABAB receptor coupling to G-proteins and ion channels. ADVANCES IN PHARMACOLOGY 2010; 58:123-47. [PMID: 20655481 DOI: 10.1016/s1054-3589(10)58006-2] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
GABA(B) receptors have been found to play a key role in regulating membrane excitability and synaptic transmission in the brain. The GABA(B) receptor is a G-protein coupled receptor (GPCR) that associates with a subset of G-proteins (pertussis toxin sensitive Gi/o family), that in turn regulate specific ion channels and trigger cAMP cascades. In this review, we describe the relationships between the GABA(B) receptor, its effectors and associated proteins that mediate GABA(B) receptor function within the brain. We discuss a unique feature of the GABA(B) receptor, the requirement for heterodimerization to produce functional receptors, as well as an increasing body of evidence that suggests GABA(B) receptors comprise a macromolecular signaling heterocomplex, critical for efficient targeting and function of the receptors. Within this complex, GABA(B) receptors associate specifically with Gi/o G-proteins that regulate voltage-gated Ca(2+) (Ca(V)) channels, G-protein activated inwardly rectifying K(+) (GIRK) channels, and adenylyl cyclase. Numerous studies have revealed that lipid rafts, scaffold proteins, targeting motifs in the receptor, and regulators of G-protein signaling (RGS) proteins also contribute to the function of GABA(B) receptors and affect cellular processes such as receptor trafficking and activity-dependent desensitization. This complex regulation of GABA(B) receptors in the brain may provide opportunities for new ways to regulate GABA-dependent inhibition in normal and diseased states of the nervous system.
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Affiliation(s)
- Claire L Padgett
- Peptide Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
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Potential therapeutic interventions for fragile X syndrome. Trends Mol Med 2010; 16:516-27. [PMID: 20864408 DOI: 10.1016/j.molmed.2010.08.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 08/19/2010] [Accepted: 08/20/2010] [Indexed: 12/14/2022]
Abstract
Fragile X syndrome (FXS) is caused by a lack of the fragile X mental retardation protein (FMRP); FMRP deficiency in neurons of patients with FXS causes intellectual disability (IQ<70) and several behavioural problems, including hyperactivity and autistic-like features. In the brain, no gross morphological malformations have been found, although subtle spine abnormalities have been reported. FXS has been linked to altered group I metabotropic glutamate receptor (mGluR)-dependent and independent forms of synaptic plasticity. Here, we discuss potential targeted therapeutic strategies developed to specifically correct disturbances in the excitatory mGluR and the inhibitory gamma-aminobutyric (GABA) receptor pathways that have been tested in animal models and/or in clinical trials with patients with FXS.
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Gregory KJ, Dong EN, Meiler J, Conn PJ. Allosteric modulation of metabotropic glutamate receptors: structural insights and therapeutic potential. Neuropharmacology 2010; 60:66-81. [PMID: 20637216 DOI: 10.1016/j.neuropharm.2010.07.007] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 06/28/2010] [Accepted: 07/06/2010] [Indexed: 10/19/2022]
Abstract
Allosteric modulation of G protein-coupled receptors (GPCRs) represents a novel approach to the development of probes and therapeutics that is expected to enable subtype-specific regulation of central nervous system target receptors. The metabotropic glutamate receptors (mGlus) are class C GPCRs that play important neuromodulatory roles throughout the brain, as such they are attractive targets for therapeutic intervention for a number of psychiatric and neurological disorders including anxiety, depression, Fragile X Syndrome, Parkinson's disease and schizophrenia. Over the last fifteen years, selective allosteric modulators have been identified for many members of the mGlu family. The vast majority of these allosteric modulators are thought to bind within the transmembrane-spanning domains of the receptors to enhance or inhibit functional responses. A combination of mutagenesis-based studies and pharmacological approaches are beginning to provide a better understanding of mGlu allosteric sites. Collectively, when mapped onto a homology model of the different mGlu subtypes based on the β(2)-adrenergic receptor, the previous mutagenesis studies suggest commonalities in the location of allosteric sites across different members of the mGlu family. In addition, there is evidence for multiple allosteric binding pockets within the transmembrane region that can interact to modulate one another. In the absence of a class C GPCR crystal structure, this approach has shown promise with respect to the interpretation of mutagenesis data and understanding structure-activity relationships of allosteric modulator pharmacophores.
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Affiliation(s)
- Karen J Gregory
- Department of Pharmacology, Vanderbilt Program in Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232-0697, USA.
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Tu H, Xu C, Zhang W, Liu Q, Rondard P, Pin JP, Liu J. GABAB receptor activation protects neurons from apoptosis via IGF-1 receptor transactivation. J Neurosci 2010; 30:749-59. [PMID: 20071540 PMCID: PMC6633015 DOI: 10.1523/jneurosci.2343-09.2010] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 11/23/2009] [Accepted: 11/25/2009] [Indexed: 12/17/2022] Open
Abstract
The G-protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs) play key roles in cell-cell communication. Several studies revealed important synergisms between these two types of receptors, with some of the actions of either receptor being mediated through transactivation of the other. Among the large GPCR family, GABA(B) receptor is activated by the neurotransmitter GABA, and is expressed in most neurons where it mediates slow and prolonged inhibition of synaptic transmission. Here we show that this receptor is involved in the regulation of life and death decisions of cerebellar granule neurons (CGNs). We show that specific activation of GABA(B) receptor can protect neurons from apoptosis through a mechanism that involves transactivation of the IGF-1 receptor (IGF-1R). Further work demonstrated that this cross talk was dependent on G(i/o)-protein, PLC, cytosolic Ca(2+), and FAK1 but independent of PKC, while IGF-1R-induced signaling involved Src kinase, PI3 kinase, and Akt activation. These results reveal a new function for this important GPCR and further highlight the importance of functional cross-talk networks between GPCRs and RTKs. Our results reveal GABA(B) receptor as a potential drug target for the treatment of neurodegenerative disorders.
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Affiliation(s)
- Haijun Tu
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China, and
| | - Chanjuan Xu
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China, and
| | - Wenhua Zhang
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China, and
| | - Qiuyao Liu
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China, and
| | - Philippe Rondard
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique Fonctionnelle, Inserm, U661 and Université Montpellier 1, 2, Montpellier F-34000, France
| | - Jean-Philippe Pin
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique Fonctionnelle, Inserm, U661 and Université Montpellier 1, 2, Montpellier F-34000, France
| | - Jianfeng Liu
- Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China, and
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Froestl W. Chemistry and Pharmacology of GABAB Receptor Ligands. GABABRECEPTOR PHARMACOLOGY - A TRIBUTE TO NORMAN BOWERY 2010; 58:19-62. [DOI: 10.1016/s1054-3589(10)58002-5] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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49
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Richer M, David M, Villeneuve LR, Trieu P, Ethier N, Pétrin D, Mamarbachi AM, Hébert TE. GABA-B(1) receptors are coupled to the ERK1/2 MAP kinase pathway in the absence of GABA-B(2) subunits. J Mol Neurosci 2008; 38:67-79. [PMID: 19052921 DOI: 10.1007/s12031-008-9163-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Accepted: 11/06/2008] [Indexed: 01/22/2023]
Abstract
In the current model of gamma-aminobutyric acid (GABA) B receptor function, there is a requirement for GABA-B(1/2) heterodimerisation for targetting to the cell surface. However, different lines of evidence suggest that the GABA-B(1) subunit can form a functional receptor in the absence of GABA-B(2). We observed coupling of endogenous GABA-B(1) receptors in the DI-TNC1 glial cell line to the ERK pathway in response to baclofen even though these cells do not express GABA-B(2). GABA-B(1A) receptors were also able to mediate a rapid, transient, and dose-dependent activation of the ERK1/2 MAP kinase pathway when transfected alone into HEK 293 cells. The response was abolished by G(i/o) and MEK inhibition, potentiated by inhibitors of phospholipase C and protein kinase C and did not involve PI-3-kinase activity. Finally, using bioluminescence resonance energy transfer and co-immunoprecipitation, we show the existence of homodimeric GABA-B(1A) receptors in transfected HEK293 cells. Altogether, our observations show that GABA-B(1A) receptors are able to activate the ERK1/2 pathway despite the absence of surface targetting partner GABA-B(2) in both HEK 293 cells and the DI-TNC1 cell line.
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Affiliation(s)
- Maxime Richer
- Département de biochimie and Groupe de recherche universitaire sur le médicament (GRUM), Université de Montréal, Montréal, Québec, Canada
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Li X, Cao JH, Li Y, Rondard P, Zhang Y, Yi P, Liu JF, Nan FJ. Activity-Based Probe for Specific Photoaffinity Labeling γ-Aminobutyric Acid B (GABAB) Receptors on Living Cells: Design, Synthesis, and Biological Evaluation. J Med Chem 2008; 51:3057-60. [DOI: 10.1021/jm800140f] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Xin Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan, Hubei, China, National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China, and Institute of Functional Genomics, CNRS UMR5203, INSERM U661, University of
| | - Jian-Hua Cao
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan, Hubei, China, National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China, and Institute of Functional Genomics, CNRS UMR5203, INSERM U661, University of
| | - Ying Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan, Hubei, China, National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China, and Institute of Functional Genomics, CNRS UMR5203, INSERM U661, University of
| | - Philippe Rondard
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan, Hubei, China, National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China, and Institute of Functional Genomics, CNRS UMR5203, INSERM U661, University of
| | - Yang Zhang
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan, Hubei, China, National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China, and Institute of Functional Genomics, CNRS UMR5203, INSERM U661, University of
| | - Ping Yi
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan, Hubei, China, National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China, and Institute of Functional Genomics, CNRS UMR5203, INSERM U661, University of
| | - Jian-Feng Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan, Hubei, China, National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China, and Institute of Functional Genomics, CNRS UMR5203, INSERM U661, University of
| | - Fa-Jun Nan
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan, Hubei, China, National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China, and Institute of Functional Genomics, CNRS UMR5203, INSERM U661, University of
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