1
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Wang W, Liu X. Mechanism of human α3β GlyR modulation in inflammatory pain and 2, 6-DTBP interaction. RESEARCH SQUARE 2024:rs.3.rs-4402878. [PMID: 39149480 PMCID: PMC11326354 DOI: 10.21203/rs.3.rs-4402878/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
α3β glycine receptor (GlyR) is a subtype of the GlyRs that belongs to the Cys-loop receptor superfamily. It is a target for non-psychoactive pain control drug development due to its high expression in the spinal dorsal horn and indispensable roles in pain sensation. α3β GlyR activity is inhibited by a phosphorylation in the large internal M3/M4 loop of α3 through the prostaglandin E2 (PGE2) pathway, which can be reverted by a small molecule analgesic, 2, 6-DTBP. However, the mechanism of regulation by phosphorylation or 2, 6-DTBP is unknown. Here we show M3/M4 loop compaction through phosphorylation and 2, 6-DTBP binding, which in turn changes the local environment and rearranges ion conduction pore conformation to modulate α3β GlyR activity. We resolved glycine-bound structures of α3β GlyR with and without phosphorylation, as well as in the presence of 2, 6-DTBP and found no change in functional states upon phosphorylation, but transition to an asymmetric super open pore by 2, 6-DTBP binding. Single-molecule Forster resonance energy transfer (smFRET) experiment shows compaction of M3/M4 loop towards the pore upon phosphorylation, and further compaction by 2, 6-DTBP. Our results reveal a localized interaction model where M3/M4 loop modulate GlyR function through physical proximation. This regulation mechanism should inform on pain medication development targeting GlyRs. Our strategy allowed investigation of how post-translational modification of an unstructured loop modulate channel conduction, which we anticipate will be applicable to intrinsically disordered loops ubiquitously found in ion channels.
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Affiliation(s)
- Weiwei Wang
- University of Texas Southwestern Medical Center
| | - Xiaofen Liu
- University of Texas Southwestern Medical Center
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2
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Fan P, Liu R, Li Y, Wang S, Li T. Study on the Mechanisms of Glrα3 in Pain Sensitization of Endometriosis. Int J Mol Sci 2024; 25:8143. [PMID: 39125713 PMCID: PMC11312134 DOI: 10.3390/ijms25158143] [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: 06/21/2024] [Revised: 07/21/2024] [Accepted: 07/23/2024] [Indexed: 08/12/2024] Open
Abstract
Endometriosis, often associated with chronic pelvic pain, can lead to anxiety and depression. This study investigates the role and mechanism of Glycine receptor alpha 3 (Glrα3) in the central sensitization of pain in endometriosis, aiming to identify new therapeutic targets. Using a Glrα3 knockout mouse model of endometriosis, we employed behavioral tests, qPCR, immunofluorescence, Nissl staining, MRI, and Western blot to assess the involvement of Glrα3 in central pain sensitization. Our results indicate that endometriosis-induced hyperalgesia and anxiety-depressive-like behaviors are linked to increased Glrα3 expression. Chronic pain in endometriosis leads to gray matter changes in the sensory and insular cortices, with Glrα3 playing a significant role. The inhibition of Glrα3 alleviates pain, reduces neuronal abnormalities, and decreases glial cell activation. The absence of Glrα3 effectively regulates the central sensitization of pain in endometriosis by inhibiting glial cell activation and maintaining neuronal stability. This study offers new therapeutic avenues for the clinical treatment of endometriosis-related pain.
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Affiliation(s)
- Peiya Fan
- Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; (P.F.); (R.L.); (Y.L.); (S.W.)
- Key Laboratory of Cancer Invasion and Metastasis (Ministry of Education), Hubei Key Laboratory of Tumor Invasion and Metastasis, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Rong Liu
- Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; (P.F.); (R.L.); (Y.L.); (S.W.)
- Key Laboratory of Cancer Invasion and Metastasis (Ministry of Education), Hubei Key Laboratory of Tumor Invasion and Metastasis, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Yan Li
- Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; (P.F.); (R.L.); (Y.L.); (S.W.)
- Key Laboratory of Cancer Invasion and Metastasis (Ministry of Education), Hubei Key Laboratory of Tumor Invasion and Metastasis, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Shixuan Wang
- Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; (P.F.); (R.L.); (Y.L.); (S.W.)
- Key Laboratory of Cancer Invasion and Metastasis (Ministry of Education), Hubei Key Laboratory of Tumor Invasion and Metastasis, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Tian Li
- Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; (P.F.); (R.L.); (Y.L.); (S.W.)
- Key Laboratory of Cancer Invasion and Metastasis (Ministry of Education), Hubei Key Laboratory of Tumor Invasion and Metastasis, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China
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3
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Weman HM, Ceder MM, Ahemaiti A, Magnusson KA, Henriksson K, Andréasson L, Lagerström MC. Spinal Glycine Receptor Alpha 3 Cells Communicate Sensations of Chemical Itch in Hairy Skin. J Neurosci 2024; 44:e1585232024. [PMID: 38553047 PMCID: PMC11079978 DOI: 10.1523/jneurosci.1585-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 01/31/2024] [Accepted: 02/15/2024] [Indexed: 05/12/2024] Open
Abstract
Glycinergic neurons regulate nociceptive and pruriceptive signaling in the spinal cord, but the identity and role of the glycine-regulated neurons are not fully known. Herein, we have characterized spinal glycine receptor alpha 3 (Glra3) subunit-expressing neurons in Glra3-Cre female and male mice. Glra3-Cre(+) neurons express Glra3, are located mainly in laminae III-VI, and respond to glycine. Chemogenetic activation of spinal Glra3-Cre(+) neurons induced biting/licking, stomping, and guarding behaviors, indicative of both a nociceptive and pruriceptive role for this population. Chemogenetic inhibition did not affect mechanical or thermal responses but reduced behaviors evoked by compound 48/80 and chloroquine, revealing a pruriceptive role for these neurons. Spinal cells activated by compound 48/80 or chloroquine express Glra3, further supporting the phenotype. Retrograde tracing revealed that spinal Glra3-Cre(+) neurons receive input from afferents associated with pain and itch, and dorsal root stimulation validated the monosynaptic input. In conclusion, these results show that spinal Glra3(+) neurons contribute to acute communication of compound 48/80- and chloroquine-induced itch in hairy skin.
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Affiliation(s)
- Hannah M Weman
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala 75108, Sweden
| | - Mikaela M Ceder
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala 75108, Sweden
| | - Aikeremu Ahemaiti
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala 75108, Sweden
| | - Kajsa A Magnusson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala 75108, Sweden
| | - Katharina Henriksson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala 75108, Sweden
| | - Linn Andréasson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala 75108, Sweden
| | - Malin C Lagerström
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala 75108, Sweden
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4
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Werynska K, Neumann E, Cramer T, Ganley RP, Gingras J, Zeilhofer HU. A phospho-deficient α3 glycine receptor mutation alters synaptic glycine and GABA release in mouse spinal dorsal horn neurons. J Physiol 2023; 601:4121-4133. [PMID: 37598301 DOI: 10.1113/jp284589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 08/03/2023] [Indexed: 08/21/2023] Open
Abstract
Glycine receptors (GlyRs), together with GABAA receptors, mediate postsynaptic inhibition in most spinal cord and hindbrain neurons. In several CNS regions, GlyRs are also expressed in presynaptic terminals. Here, we analysed the effects of a phospho-deficient mutation (S346A) in GlyR α3 subunits on inhibitory synaptic transmission in superficial spinal dorsal horn neurons, where this subunit is abundantly expressed. Unexpectedly, we found that not only were the amplitudes of evoked glycinergic inhibitory postsynaptic currents (IPSCs) significantly larger in GlyRα3(S346A) mice than in mice expressing wild-type α3GlyRs (GlyRα3(WT) mice), but so were those of GABAergic IPSCs. Decreased frequencies of spontaneously occurring glycinergic and GABAergic miniature IPSCs (mIPSCs) with no accompanying change in mIPSC amplitudes suggested a change in presynaptic transmitter release. Paired-pulse experiments on glycinergic IPSCs revealed an increased paired-pulse ratio and a smaller coefficient of variation in GlyRα3(S346A) mice, which together indicate a reduction in transmitter release probability and an increase in the number of releasable vesicles. Paired-pulse ratios of GABAergic IPSCs recorded in the presence of strychnine were not different between genotypes, while the coefficient of variation was smaller in GlyRα3(S346A) mice, demonstrating that the decrease in release probability was readily reversible by GlyR blockade, while the difference in the size of the pool of releasable vesicles remained. Taken together, our results suggest that presynaptic α3 GlyRs regulate synaptic glycine and GABA release in superficial dorsal horn neurons, and that this effect is potentially regulated by their phosphorylation status. KEY POINTS: A serine-to-alanine point mutation was introduced into the glycine receptor α3 subunit of mice. This point mutation renders α3 glycine receptors resistant to protein kinase A mediated phosphorylation but has otherwise only small effects on receptor function. Patch-clamp recordings from neurons in mouse spinal cord slices revealed an unexpected increase in the amplitudes of both glycinergic and GABAergic evoked inhibitory postsynaptic currents (IPSCs). Miniature IPSCs, paired-pulse ratios and synaptic variation analyses indicate a change in synaptic glycine and GABA release. The results strongly suggest that α3 subunit-containing glycine receptors are expressed on presynaptic terminals of inhibitory dorsal horn neurons where they regulate transmitter release.
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Affiliation(s)
- Karolina Werynska
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Drug Discovery Network Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Elena Neumann
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Teresa Cramer
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Robert P Ganley
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | | | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Drug Discovery Network Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
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5
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Ceder MM, Weman HM, Johansson E, Henriksson K, Magnusson KA, Roman E, Lagerström MC. The glycine receptor alpha 3 subunit mRNA expression shows sex-dependent differences in the adult mouse brain. BMC Neurosci 2023; 24:32. [PMID: 37264306 DOI: 10.1186/s12868-023-00800-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/28/2023] [Indexed: 06/03/2023] Open
Abstract
BACKGROUND The glycinergic system plays an important inhibitory role in the mouse central nervous system, where glycine controls the excitability of spinal itch- and pain-mediating neurons. Impairments of the glycine receptors can cause motor and sensory deficits. Glycine exerts inhibition through interaction with ligand-gated ion channels composed of alpha and beta subunits. We have investigated the mRNA expression of the glycine receptor alpha 3 (Glra3) subunit in the nervous system as well as in several peripheral organs of female and male mice. RESULTS Single-cell RNA sequencing (scRNA-seq) data analysis on the Zeisel et al. (2018) dataset indicated widespread but low expression of Glra3 in vesicular glutamate transporter 2 (Vglut2, Slc17a6) positive and vesicular inhibitory amino acid transporter (Viaat, Slc32a1)positive neurons of the mouse central nervous system. Highest occurrence of Glra3 expression was identified in the cortex, amygdala, and striatal regions, as well as in the hypothalamus, brainstem and spinal cord. Bulk quantitative real-time-PCR (qRT-PCR) analysis demonstrated Glra3 expression in cortex, amygdala, striatum, hypothalamus, thalamus, pituitary gland, hippocampus, cerebellum, brainstem, and spinal cord. Additionally, male mice expressed higher levels of Glra3 in all investigated brain areas compared with female mice. Lastly, RNAscope spatially validated Glra3 expression in the areas indicated by the single-cell and bulk analyses. Moreover, RNAscope analysis confirmed co-localization of Glra3 with Slc17a6 or Slc32a1 in the central nervous system areas suggested from the single-cell data. CONCLUSIONS Glra3 expression is low but widespread in the mouse central nervous system. Clear sex-dependent differences have been identified, indicating higher levels of Glra3 in several telencephalic and diencephalic areas, as well as in cerebellum and brainstem, in male mice compared with female mice.
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Affiliation(s)
- Mikaela M Ceder
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Hannah M Weman
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Ebba Johansson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Katharina Henriksson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Kajsa A Magnusson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Erika Roman
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
- Neuropharmacology and Addiction, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Malin C Lagerström
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
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6
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Frezel N, Ranucci M, Foster E, Wende H, Pelczar P, Mendes R, Ganley RP, Werynska K, d'Aquin S, Beccarini C, Birchmeier C, Zeilhofer HU, Wildner H. c-Maf-positive spinal cord neurons are critical elements of a dorsal horn circuit for mechanical hypersensitivity in neuropathy. Cell Rep 2023; 42:112295. [PMID: 36947543 PMCID: PMC10157139 DOI: 10.1016/j.celrep.2023.112295] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/02/2023] [Accepted: 03/06/2023] [Indexed: 03/23/2023] Open
Abstract
Corticospinal tract (CST) neurons innervate the deep spinal dorsal horn to sustain chronic neuropathic pain. The majority of neurons targeted by the CST are interneurons expressing the transcription factor c-Maf. Here, we used intersectional genetics to decipher the function of these neurons in dorsal horn sensory circuits. We find that excitatory c-Maf (c-MafEX) neurons receive sensory input mainly from myelinated fibers and target deep dorsal horn parabrachial projection neurons and superficial dorsal horn neurons, thereby connecting non-nociceptive input to nociceptive output structures. Silencing c-MafEX neurons has little effect in healthy mice but alleviates mechanical hypersensitivity in neuropathic mice. c-MafEX neurons also receive input from inhibitory c-Maf and parvalbumin neurons, and compromising inhibition by these neurons caused mechanical hypersensitivity and spontaneous aversive behaviors reminiscent of c-MafEX neuron activation. Our study identifies c-MafEX neurons as normally silent second-order nociceptors that become engaged in pathological pain signaling upon loss of inhibitory control.
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Affiliation(s)
- Noémie Frezel
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Matteo Ranucci
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Edmund Foster
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | | | - Pawel Pelczar
- Center for Transgenic Models (CTM), University of Basel, 4001 Basel, Switzerland
| | - Raquel Mendes
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Robert P Ganley
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Karolina Werynska
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Simon d'Aquin
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Camilla Beccarini
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | | | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland; Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, 8092 Zürich, Switzerland.
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland.
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7
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Simard JR, Michelsen K, Wang Y, Yang C, Youngblood B, Grubinska B, Taborn K, Gillie DJ, Cook K, Chung K, Long AM, Hall BE, Shaffer PL, Foti RS, Gingras J. Modulation of Ligand-Gated Glycine Receptors Via Functional Monoclonal Antibodies. J Pharmacol Exp Ther 2022; 383:56-69. [PMID: 35926871 DOI: 10.1124/jpet.121.001026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 07/15/2022] [Accepted: 07/19/2022] [Indexed: 12/15/2022] Open
Abstract
Ion channels are targets of considerable therapeutic interest to address a wide variety of neurologic indications, including pain perception. Current pharmacological strategies have focused mostly on small molecule approaches that can be limited by selectivity requirements within members of a channel family or superfamily. Therapeutic antibodies have been proposed, designed, and characterized to alleviate this selectivity limitation; however, there are no Food and Drug Administration-approved therapeutic antibody-based drugs targeting ion channels on the market to date. Here, in an effort to identify novel classes of engineered ion channel modulators for potential neurologic therapeutic applications, we report the generation and characterization of six (EC50 < 25nM) Cys-loop receptor family monoclonal antibodies with modulatory function against rat and human glycine receptor alpha 1 (GlyRα1) and/or GlyRα3. These antibodies have activating (i.e., positive modulator) or inhibiting (i.e., negative modulator) profiles. Moreover, GlyRα3 selectivity was successfully achieved for two of the three positive modulators identified. When dosed intravenously, the antibodies achieved sufficient brain exposure to cover their calculated in vitro EC50 values. When compared head-to-head at identical exposures, the GlyRα3-selective antibody showed a more desirable safety profile over the nonselective antibody, thus demonstrating, for the first time, an advantage for GlyRα3-selectivity. Our data show that ligand-gated ion channels of the glycine receptor family within the central nervous system can be functionally modulated by engineered biologics in a dose-dependent manner and that, despite high protein homology between the alpha subunits, selectivity can be achieved within this receptor family, resulting in future therapeutic candidates with more desirable drug safety profiles. SIGNIFICANCE STATEMENT: This study presents immunization and multiplatform screening approaches to generate a diverse library of functional antibodies (agonist, potentiator, or inhibitory) raised against human glycine receptors (GlyRs). This study also demonstrates the feasibility of acquiring alpha subunit selectivity, a desirable therapeutic profile. When tested in vivo, these tool molecules demonstrated an increased safety profile in favor of GlyRα3-selectivity. These are the first reported functional GlyR antibodies that may open new avenues to treating central nervous system diseases with subunit selective biologics.
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Affiliation(s)
- Jeffrey R Simard
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Klaus Michelsen
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Yan Wang
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Chunhua Yang
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Beth Youngblood
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Barbara Grubinska
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Kristin Taborn
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Daniel J Gillie
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Kevin Cook
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Kyu Chung
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Alexander M Long
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Brian E Hall
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Paul L Shaffer
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Robert S Foti
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
| | - Jacinthe Gingras
- Departments of Neuroscience (J.R.S., C.Y., B.Y. B.G., K.T., D.J.G., J.G.), Molecular Engineering (K.M., A.M.L., P.L.S.), Protein Technologies (Y.W., B.E.H.), and Pharmacokinetics and Drug Metabolism (R.S.F.), Amgen Research, Cambridge, Massachusetts; and Department of Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Boulevard, South San Francisco, California (K.Co., K.Ch.)
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8
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Peiser-Oliver JM, Evans S, Adams DJ, Christie MJ, Vandenberg RJ, Mohammadi SA. Glycinergic Modulation of Pain in Behavioral Animal Models. Front Pharmacol 2022; 13:860903. [PMID: 35694265 PMCID: PMC9174897 DOI: 10.3389/fphar.2022.860903] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/19/2022] [Indexed: 11/16/2022] Open
Abstract
Animal models of human pain conditions allow for detailed interrogation of known and hypothesized mechanisms of pain physiology in awake, behaving organisms. The importance of the glycinergic system for pain modulation is well known; however, manipulation of this system to treat and alleviate pain has not yet reached the sophistication required for the clinic. Here, we review the current literature on what animal behavioral studies have allowed us to elucidate about glycinergic pain modulation, and the progress toward clinical treatments so far. First, we outline the animal pain models that have been used, such as nerve injury models for neuropathic pain, chemogenic pain models for acute and inflammatory pain, and other models that mimic painful human pathologies such as diabetic neuropathy. We then discuss the genetic approaches to animal models that have identified the crucial glycinergic machinery involved in neuropathic and inflammatory pain. Specifically, two glycine receptor (GlyR) subtypes, GlyRα1(β) and GlyRα3(β), and the two glycine transporters (GlyT), GlyT1 and GlyT2. Finally, we review the different pharmacological approaches to manipulating the glycinergic system for pain management in animal models, such as partial vs. full agonism, reversibility, and multi-target approaches. We discuss the benefits and pitfalls of using animal models in drug development broadly, as well as the progress of glycinergic treatments from preclinical to clinical trials.
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Affiliation(s)
| | - Sally Evans
- School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
| | - David J. Adams
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
| | | | | | - Sarasa A. Mohammadi
- School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
- *Correspondence: Sarasa A. Mohammadi,
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Chen X, Wilson KA, Schaefer N, De Hayr L, Windsor M, Scalais E, van Rijckevorsel G, Stouffs K, Villmann C, O’Mara ML, Lynch JW, Harvey RJ. Loss, Gain and Altered Function of GlyR α2 Subunit Mutations in Neurodevelopmental Disorders. Front Mol Neurosci 2022; 15:886729. [PMID: 35571374 PMCID: PMC9103196 DOI: 10.3389/fnmol.2022.886729] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/07/2022] [Indexed: 12/11/2022] Open
Abstract
Glycine receptors (GlyRs) containing the α2 subunit govern cell fate, neuronal migration and synaptogenesis in the developing cortex and spinal cord. Rare missense variants and microdeletions in the X-linked GlyR α2 subunit gene (GLRA2) have been associated with human autism spectrum disorder (ASD), where they typically cause a loss-of-function via protein truncation, reduced cell-surface trafficking and/or reduced glycine sensitivity (e.g., GLRA2Δex8-9 and extracellular domain variants p.N109S and p.R126Q). However, the GlyR α2 missense variant p.R323L in the intracellular M3-M4 domain results in a gain-of-function characterized by slower synaptic decay times, longer duration active periods and increases in channel conductance. This study reports the functional characterization of four missense variants in GLRA2 associated with ASD or developmental disorders (p.V-22L, p.N38K, p.K213E, p.T269M) using a combination of bioinformatics, molecular dynamics simulations, cellular models of GlyR trafficking and electrophysiology in artificial synapses. The GlyR α2V–22L variant resulted in altered predicted signal peptide cleavage and a reduction in cell-surface expression, suggestive of a partial loss-of-function. Similarly, GlyR α2N38K homomers showed reduced cell-surface expression, a reduced affinity for glycine and a reduced magnitude of IPSCs in artificial synapses. By contrast, GlyR α2K213E homomers showed a slight reduction in cell-surface expression, but IPSCs were larger, with faster rise/decay times, suggesting a gain-of-function. Lastly, GlyR α2T269M homomers exhibited a high glycine sensitivity accompanied by a substantial leak current, suggestive of an altered function that could dramatically enhance glycinergic signaling. These results may explain the heterogeneity of clinical phenotypes associated with GLRA2 mutations and reveal that missense variants can result in a loss, gain or alteration of GlyR α2 function. In turn, these GlyR α2 missense variants are likely to either negatively or positively deregulate cortical progenitor homeostasis and neuronal migration in the developing brain, leading to changes in cognition, learning, and memory.
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Affiliation(s)
- Xiumin Chen
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Katie A. Wilson
- Research School of Chemistry, The Australian National University, Canberra, ACT, Australia
| | - Natascha Schaefer
- Institute of Clinical Neurobiology, University Hospital, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Lachlan De Hayr
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Maroochydore, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Mark Windsor
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Maroochydore, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Emmanuel Scalais
- Neurologie Pédiatrique, Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg
| | | | - Katrien Stouffs
- Center for Medical Genetics, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium
| | - Carmen Villmann
- Institute of Clinical Neurobiology, University Hospital, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Megan L. O’Mara
- Research School of Chemistry, The Australian National University, Canberra, ACT, Australia
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, Australia
| | - Joseph W. Lynch
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Robert J. Harvey
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Maroochydore, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, QLD, Australia
- *Correspondence: Robert J. Harvey,
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Groemer TW, Triller A, Zeilhofer HU, Becker K, Eulenburg V, Becker CM. Nociception in the Glycine Receptor Deficient Mutant Mouse Spastic. Front Mol Neurosci 2022; 15:832490. [PMID: 35548669 PMCID: PMC9082815 DOI: 10.3389/fnmol.2022.832490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 03/31/2022] [Indexed: 11/17/2022] Open
Abstract
Glycine receptors (GlyRs) are the primary mediators of fast inhibitory transmission in the mammalian spinal cord, where they modulate sensory and motor signaling. Mutations in GlyR genes as well as some other genes underlie the hereditary disorder hyperekplexia, characterized by episodic muscle stiffness and exaggerated startle responses. Here, we have investigated pain-related behavior and GlyR expression in the spinal cord of the GlyR deficient mutant mouse spastic (spa). In spastic mice, the GlyR number is reduced due to a β subunit gene (Glrb) mutation resulting in aberrant splicing of GlyRβ transcripts. Via direct physical interaction with the GlyR anchoring protein gephyrin, this subunit is crucially involved in the postsynaptic clustering of heteromeric GlyRs. We show that the mutation differentially affects aspects of the pain-related behavior of homozygous Glrbspa/Glrbspa mice. While response latencies to noxious heat were unchanged, chemically induced pain-related behavior revealed a reduction of the licking time and an increase in flinching in spastic homozygotes during both phases of the formalin test. Mechanically induced nocifensive behavior was reduced in spastic mice, although hind paw inflammation (by zymosan) resulted in allodynia comparable to wild-type mice. Immunohistochemical staining of the spinal cord revealed a massive reduction of dotted GlyRα subunit immunoreactivity in both ventral and dorsal horns, suggesting a reduction of clustered receptors at synaptic sites. Transcripts for all GlyRα subunit variants, however, were not reduced throughout the dorsal horn of spastic mice. These findings suggest that the loss of functional GlyRβ subunits and hence synaptically localized GlyRs compromises sensory processing differentially, depending on stimulus modality.
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Affiliation(s)
- Teja Wolfgang Groemer
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Antoine Triller
- École Normale Supérieure, INSERM U 497 Biologie Cellulaire de la Synapse Normale et Pathologique, Paris, France
| | - Hanns Ulrich Zeilhofer
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Emil-Fischer-Zentrum, Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Kristina Becker
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Volker Eulenburg
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- Department für Anästhesiologie und Intensivmedizin, Universität Leipzig, Leipzig, Germany
- *Correspondence: Volker Eulenburg
| | - Cord Michael Becker
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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San Martín VP, Sazo A, Utreras E, Moraga-Cid G, Yévenes GE. Glycine Receptor Subtypes and Their Roles in Nociception and Chronic Pain. Front Mol Neurosci 2022; 15:848642. [PMID: 35401105 PMCID: PMC8984470 DOI: 10.3389/fnmol.2022.848642] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 01/28/2022] [Indexed: 01/23/2023] Open
Abstract
Disruption of the inhibitory control provided by the glycinergic system is one of the major mechanisms underlying chronic pain. In line with this concept, recent studies have provided robust proof that pharmacological intervention of glycine receptors (GlyRs) restores the inhibitory function and exerts anti-nociceptive effects on preclinical models of chronic pain. A targeted regulation of the glycinergic system requires the identification of the GlyR subtypes involved in chronic pain states. Nevertheless, the roles of individual GlyR subunits in nociception and in chronic pain are yet not well defined. This review aims to provide a systematic outline on the contribution of GlyR subtypes in chronic pain mechanisms, with a particular focus on molecular pathways of spinal glycinergic dis-inhibition mediated by post-translational modifications at the receptor level. The current experimental evidence has shown that phosphorylation of synaptic α1β and α3β GlyRs are involved in processes of spinal glycinergic dis-inhibition triggered by chronic inflammatory pain. On the other hand, the participation of α2-containing GlyRs and of β subunits in pain signaling have been less studied and remain undefined. Although many questions in the field are still unresolved, future progress in GlyR research may soon open new exciting avenues into understanding and controlling chronic pain.
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Affiliation(s)
- Victoria P. San Martín
- Department of Physiology, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile
- Millennium Nucleus for the Study of Pain (MiNuSPain), Santiago, Chile
| | - Anggelo Sazo
- Department of Physiology, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile
- Millennium Nucleus for the Study of Pain (MiNuSPain), Santiago, Chile
| | - Elías Utreras
- Millennium Nucleus for the Study of Pain (MiNuSPain), Santiago, Chile
- Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile
| | - Gustavo Moraga-Cid
- Department of Physiology, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile
- Millennium Nucleus for the Study of Pain (MiNuSPain), Santiago, Chile
| | - Gonzalo E. Yévenes
- Department of Physiology, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile
- Millennium Nucleus for the Study of Pain (MiNuSPain), Santiago, Chile
- *Correspondence: Gonzalo E. Yévenes,
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Zeilhofer HU, Werynska K, Gingras J, Yévenes GE. Glycine Receptors in Spinal Nociceptive Control-An Update. Biomolecules 2021; 11:846. [PMID: 34204137 PMCID: PMC8228028 DOI: 10.3390/biom11060846] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/03/2021] [Accepted: 06/03/2021] [Indexed: 12/12/2022] Open
Abstract
Diminished inhibitory control of spinal nociception is one of the major culprits of chronic pain states. Restoring proper synaptic inhibition is a well-established rational therapeutic approach explored by several pharmaceutical companies. A particular challenge arises from the need for site-specific intervention to avoid deleterious side effects such as sedation, addiction, or impaired motor control, which would arise from wide-range facilitation of inhibition. Specific targeting of glycinergic inhibition, which dominates in the spinal cord and parts of the hindbrain, may help reduce these side effects. Selective targeting of the α3 subtype of glycine receptors (GlyRs), which is highly enriched in the superficial layers of the spinal dorsal horn, a key site of nociceptive processing, may help to further narrow down pharmacological intervention on the nociceptive system and increase tolerability. This review provides an update on the physiological properties and functions of α3 subtype GlyRs and on the present state of related drug discovery programs.
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Affiliation(s)
- Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland;
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Vladimir Prelog Weg, CH-8093 Zürich, Switzerland
- Drug Discovery Network Zurich, University of Zurich and ETH Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Karolina Werynska
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland;
| | - Jacinthe Gingras
- Homology Medicines Inc., 1 Patriots Park, Bedford, MA 01730, USA;
| | - Gonzalo E. Yévenes
- Department of Physiology, University of Concepción, Concepción 4070386, Chile;
- Millennium Nucleus for the Study of Pain (MiNuSPain), Santiago 8320000, Chile
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