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Wang Z, Dong J, Zhang M, Wang S, Wu J, Wang S, Luo Y, Wang Y, Yin Y. Sevoflurane-induced overexpression of extrasynaptic α5-GABA AR via the RhoA/ROCK2 pathway impairs cognitive function in aged mice. Aging Cell 2024:e14209. [PMID: 38825816 DOI: 10.1111/acel.14209] [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: 01/16/2024] [Revised: 04/24/2024] [Accepted: 05/08/2024] [Indexed: 06/04/2024] Open
Abstract
Perioperative neurocognitive disorder (PND) is a serious neurologic complication in aged patients and might be associated with sevoflurane exposure. However, the specific pathogenesis is still unclear. The distribution of α5-GABAAR, a γ-aminobutyric acid type A receptor (GABAAR) subtype, at extrasynaptic sites is influenced by the anchor protein radixin, whose phosphorylation is regulated via the RhoA/ROCK2 signaling pathway and plays a crucial role in cognition. However, whether sevoflurane affects the ability of radixin phosphorylation to alter extrasynaptic receptor expression is unknown. Aged mice were exposed to sevoflurane to induce cognitive impairment. Both total proteins and membrane proteins were extracted for analysis. Cognitive function was evaluated using the Morris water maze and fear conditioning test. Western blotting was used to determine the expression of ROCK2 and the phosphorylation of radixin. Furthermore, the colocalization of p-radixin and α5-GABAAR was observed. To inhibit ROCK2 activity, either an adeno-associated virus (AAV) or fasudil hydrochloride was administered. Aged mice treated with sevoflurane exhibited significant cognitive impairment accompanied by increased membrane expression of α5-GABAAR. Moreover, the colocalization of α5-GABAAR and p-radixin increased after treatment with sevoflurane, and this change was accompanied by an increase in ROCK2 expression and radixin phosphorylation. Notably, inhibiting the RhoA/ROCK2 pathway significantly decreased the distribution of extrasynaptic α5-GABAAR and improved cognitive function. Sevoflurane activates the RhoA/ROCK2 pathway and increases the phosphorylation of radixin. Excess α5-GABAAR is anchored to extrasynaptic sites and impairs cognitive ability in aged mice. Fasudil hydrochloride administration improves cognitive function.
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Affiliation(s)
- Zhun Wang
- Department of Anesthesiology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin, China
- Key Laboratory of Cancer Prevention and Therapy, Tianjin, China
- Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Jinpeng Dong
- Department of Anesthesiology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin, China
- Key Laboratory of Cancer Prevention and Therapy, Tianjin, China
- Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Mengxue Zhang
- Department of Anesthesiology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin, China
- Key Laboratory of Cancer Prevention and Therapy, Tianjin, China
- Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Sixuan Wang
- Department of Anesthesiology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin, China
- Key Laboratory of Cancer Prevention and Therapy, Tianjin, China
- Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Jiangnan Wu
- Department of Anesthesiology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Shengran Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Academy of Military Medical Sciences, Beijing, China
| | - Yuan Luo
- State Key Laboratory of Toxicology and Medical Countermeasures, Academy of Military Medical Sciences, Beijing, China
| | - Yongan Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Academy of Military Medical Sciences, Beijing, China
| | - Yiqing Yin
- Department of Anesthesiology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin, China
- Key Laboratory of Cancer Prevention and Therapy, Tianjin, China
- Tianjin's Clinical Research Center for Cancer, Tianjin, China
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Orser BA. Discovering the Intriguing Properties of Extrasynaptic γ-Aminobutyric Acid Type A Receptors. Anesthesiology 2024; 140:1192-1200. [PMID: 38624275 DOI: 10.1097/aln.0000000000004949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Tonic inhibition in mouse hippocampal CA1 pyramidal neurons is mediated by α5 subunit-containing γ-aminobutyric acid type A receptors. By Caraiscos VB, Elliott EM, You-Ten KE, Cheng VY, Belelli D, Newell JG, Jackson MF, Lambert JJ, Rosahl TW, Wafford KA, MacDonald JF, Orser BA. Proc Natl Acad Sci U S A 2004; 101:3662-7. Reprinted with permission. In this Classic Paper Revisited, the author recounts the scientific journey leading to a report published in the Proceedings of the National Academy of Sciences (PNAS) and shares several personal stories from her formative years and "research truths" that she has learned along the way. Briefly, the principal inhibitory neurotransmitter in the brain, γ-aminobutyric acid (GABA), was conventionally thought to regulate cognitive processes by activating synaptic GABA type A (GABAA) receptors and generating transient inhibitory synaptic currents. However, the author's laboratory team discovered a novel nonsynaptic form of tonic inhibition in hippocampal pyramidal neurons, mediated by extrasynaptic GABAA receptors that are pharmacologically distinct from synaptic GABAA receptors. This tonic current is highly sensitive to most general anesthetics, including sevoflurane and propofol, and likely contributes to the memory-blocking properties of these drugs. Before the publication in PNAS, the subunit composition of GABAA receptors that generate the tonic current was unknown. The team's research showed that GABAA receptors containing the α5 subunit (α5GABAARs) generated the tonic inhibitory current in hippocampal neurons. α5GABAARs are highly sensitive to GABA, desensitize slowly, and are thus well suited for detecting low, persistent, ambient concentrations of GABA in the extracellular space. Interest in α5GABAARs has surged since the PNAS report, driven by their pivotal roles in cognitive processes and their potential as therapeutic targets for treating various neurologic disorders.
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Affiliation(s)
- Beverley A Orser
- Department of Anesthesiology and Pain Medicine, and Department of Physiology, University of Toronto, Toronto, Canada
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Topchiy I, Mohbat J, Folorunso OO, Wang ZZ, Lazcano-Etchebarne C, Engin E. GABA system as the cause and effect in early development. Neurosci Biobehav Rev 2024; 161:105651. [PMID: 38579901 PMCID: PMC11081854 DOI: 10.1016/j.neubiorev.2024.105651] [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: 01/03/2024] [Revised: 03/05/2024] [Accepted: 04/01/2024] [Indexed: 04/07/2024]
Abstract
GABA is the primary inhibitory neurotransmitter in the adult brain and through its actions on GABAARs, it protects against excitotoxicity and seizure activity, ensures temporal fidelity of neurotransmission, and regulates concerted rhythmic activity of neuronal populations. In the developing brain, the development of GABAergic neurons precedes that of glutamatergic neurons and the GABA system serves as a guide and framework for the development of other brain systems. Despite this early start, the maturation of the GABA system also continues well into the early postnatal period. In this review, we organize evidence around two scenarios based on the essential and protracted nature of GABA system development: 1) disruptions in the development of the GABA system can lead to large scale disruptions in other developmental processes (i.e., GABA as the cause), 2) protracted maturation of this system makes it vulnerable to the effects of developmental insults (i.e., GABA as the effect). While ample evidence supports the importance of GABA/GABAAR system in both scenarios, large gaps in existing knowledge prevent strong mechanistic conclusions.
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Affiliation(s)
- Irina Topchiy
- Division of Basic Neuroscience, McLean Hospital, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA
| | - Julie Mohbat
- Division of Basic Neuroscience, McLean Hospital, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA; School of Life Sciences, Ecole Polytechnique Federale de Lausanne, Lausanne CH-1015, Switzerland
| | - Oluwarotimi O Folorunso
- Division of Basic Neuroscience, McLean Hospital, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA
| | - Ziyi Zephyr Wang
- Division of Basic Neuroscience, McLean Hospital, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA
| | | | - Elif Engin
- Division of Basic Neuroscience, McLean Hospital, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA.
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Wang S, Wang S, Wang Z, Dong J, Zhang M, Wang Y, Wang J, Jia B, Luo Y, Yin Y. The changing of α5-GABAA receptors expression and distribution participate in sevoflurane-induced learning and memory impairment in young mice. CNS Neurosci Ther 2024; 30:e14716. [PMID: 38698533 PMCID: PMC11066188 DOI: 10.1111/cns.14716] [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: 12/14/2023] [Revised: 03/04/2024] [Accepted: 03/29/2024] [Indexed: 05/05/2024] Open
Abstract
BACKGROUND Sevoflurane is a superior agent for maintaining anesthesia during surgical procedures. However, the neurotoxic mechanisms of clinical concentration remain poorly understood. Sevoflurane can interfere with the normal function of neurons and synapses and impair cognitive function by acting on α5-GABAAR. METHODS Using MWM test, we evaluated cognitive abilities in mice following 1 h of anesthesia with 2.7%-3% sevoflurane. Based on hippocampal transcriptome analysis, we analyzed the differential genes and IL-6 24 h post-anesthesia. Western blot and RT-PCR were performed to measure the levels of α5-GABAAR, Radixin, P-ERM, P-Radixin, Gephyrin, IL-6, and ROCK. The spatial distribution and expression of α5-GABAAR on neuronal somata were analyzed using histological and three-dimensional imaging techniques. RESULTS MWM test indicated that partial long-term learning and memory impairment. Combining molecular biology and histological analysis, our studies have demonstrated that sevoflurane induces immunosuppression, characterized by reduced IL-6 expression levels, and that enhanced Radixin dephosphorylation undermines the microstructural stability of α5-GABAAR, leading to its dissociation from synaptic exterior and resulting in a disordered distribution in α5-GABAAR expression within neuronal cell bodies. On the synaptic cleft, the expression level of α5-GABAAR remained unchanged, the spatial distribution became more compact, with an increased fluorescence intensity per voxel. On the extra-synaptic space, the expression level of α5-GABAAR decreased within unchanged spatial distribution, accompanied by an increased fluorescence intensity per voxel. CONCLUSION Dysregulated α5-GABAAR expression and distribution contributes to sevoflurane-induced partial long-term learning and memory impairment, which lays the foundation for elucidating the underlying mechanisms in future studies.
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Affiliation(s)
- Shengran Wang
- National Clinical Research Center for CancerTianjin Medical University Cancer Institute and HospitalTianjinChina
- Key Laboratory of Cancer Prevention and TherapyTianjinChina
- Tianjin's Clinical Research Center for CancerTianjinChina
- State Key Laboratory of Toxicology and Medical CountermeasuresBeijing Institute of Pharmacology and ToxicologyBeijingChina
| | - Sixuan Wang
- National Clinical Research Center for CancerTianjin Medical University Cancer Institute and HospitalTianjinChina
- Key Laboratory of Cancer Prevention and TherapyTianjinChina
- Tianjin's Clinical Research Center for CancerTianjinChina
| | - Zhun Wang
- National Clinical Research Center for CancerTianjin Medical University Cancer Institute and HospitalTianjinChina
- Key Laboratory of Cancer Prevention and TherapyTianjinChina
- Tianjin's Clinical Research Center for CancerTianjinChina
| | - Jinpeng Dong
- National Clinical Research Center for CancerTianjin Medical University Cancer Institute and HospitalTianjinChina
- Key Laboratory of Cancer Prevention and TherapyTianjinChina
- Tianjin's Clinical Research Center for CancerTianjinChina
| | - Mengxue Zhang
- National Clinical Research Center for CancerTianjin Medical University Cancer Institute and HospitalTianjinChina
- Key Laboratory of Cancer Prevention and TherapyTianjinChina
- Tianjin's Clinical Research Center for CancerTianjinChina
| | - Yongan Wang
- State Key Laboratory of Toxicology and Medical CountermeasuresBeijing Institute of Pharmacology and ToxicologyBeijingChina
| | - Jianyu Wang
- Department of Pharmaceutics, School of PharmacyShenyang Pharmaceutical UniversityBenxiChina
| | - Beichen Jia
- State Key Laboratory of Toxicology and Medical CountermeasuresBeijing Institute of Pharmacology and ToxicologyBeijingChina
| | - Yuan Luo
- State Key Laboratory of Toxicology and Medical CountermeasuresBeijing Institute of Pharmacology and ToxicologyBeijingChina
| | - Yiqing Yin
- National Clinical Research Center for CancerTianjin Medical University Cancer Institute and HospitalTianjinChina
- Key Laboratory of Cancer Prevention and TherapyTianjinChina
- Tianjin's Clinical Research Center for CancerTianjinChina
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Phillips S, Chatham JC, McMahon LL. Forskolin reverses the O-GlcNAcylation dependent decrease in GABAAR current amplitude at hippocampal synapses possibly at a neurosteroid site on GABAARs. RESEARCH SQUARE 2024:rs.3.rs-4140038. [PMID: 38659738 PMCID: PMC11042418 DOI: 10.21203/rs.3.rs-4140038/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
GABAergic transmission is influenced by post-translational modifications, like phosphorylation, impacting channel conductance, allosteric modulator sensitivity, and membrane trafficking. O-GlcNAcylation is a post-translational modification involving the O-linked attachment of β-N-acetylglucosamine on serine/threonine residues. Previously we reported an acute increase in O-GlcNAcylation elicits a long-term depression of evoked GABAAR inhibitory post synaptic currents (eIPSCs) onto hippocampal principal cells. Importantly, O-GlcNAcylation and phosphorylation can co-occur or compete for the same residue; whether they interact in modulating GABAergic IPSCs is unknown. We tested this by recording IPSCs from hippocampal principal cells and pharmacologically increased O-GlcNAcylation, before or after increasing serine phosphorylation using the adenylate cyclase activator, forskolin. Although forskolin had no significant effect on baseline eIPSC amplitude, we found that a prior increase in O-GlcNAcylation unmasks a forskolin-dependent increase in eIPSC amplitude, reversing the O-GlcNAc-induced eIPSC depression. Inhibition of adenylate cyclase or protein kinase A did not prevent the potentiating effect of forskolin, indicating serine phosphorylation is not the mechanism. Surprisingly, increasing O-GlcNAcylation also unmasked a potentiating effect of the neurosteroids 5α-pregnane-3α,21-diol-20-one (THDOC) and progesterone on eIPSC amplitude, mimicking forskolin. Our findings show under conditions of heightened O-GlcNAcylation, the neurosteroid site on synaptic GABAARs is accessible to agonists, permitting strengthening of synaptic inhibition.
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Phillips S, Chatham JC, McMahon L. Forskolin reverses the O-GlcNAcylation dependent decrease in GABAAR current amplitude at hippocampal synapses possibly through a neurosteroid site on GABAARs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.06.583612. [PMID: 38496430 PMCID: PMC10942432 DOI: 10.1101/2024.03.06.583612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
GABAergic transmission is influenced by post-translational modifications, like phosphorylation, impacting channel conductance, allosteric modulator sensitivity, and membrane trafficking. O-GlcNAcylation is a post-translational modification involving the O-linked attachment of β-N-acetylglucosamine on serine/threonine residues. Previously we reported an acute increase in O-GlcNAcylation elicits a long-term depression of evoked GABAAR inhibitory post synaptic currents (eIPSCs) onto hippocampal principal cells. Importantly O-GlcNAcylation and phosphorylation can co-occur or compete for the same residue; whether they interact in modulating GABAergic IPSCs is unknown. We tested this by recording IPSCs from hippocampal principal cells and pharmacologically increased O-GlcNAcylation, before or after increasing serine phosphorylation using the adenylate cyclase activator, forskolin. Although forskolin had no significant effect on baseline eIPSC amplitude, we found that a prior increase in O-GlcNAcylation unmasks a forskolin-dependent increase in eIPSC amplitude, reversing the O-GlcNAc-induced eIPSC depression. Inhibition of adenylate cyclase or protein kinase A did not prevent the potentiating effect of forskolin, indicating serine phosphorylation is not the mechanism. Surprisingly, increasing O-GlcNAcylation also unmasked a potentiating effect of the neurosteroids 5α-pregnane-3α,21-diol-20-one (THDOC) and progesterone on eIPSC amplitude, mimicking forskolin. Our findings show under conditions of heightened O-GlcNAcylation, the neurosteroid site on synaptic GABAARs is accessible to agonists, permitting strengthening of synaptic inhibition.
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McCoy AM, Prevot TD, Mian MY, Sharmin D, Ahmad AN, Cook JM, Sibille EL, Lodge DJ. Extrasynaptic localization is essential for α5GABA A receptor modulation of dopamine system function. eNeuro 2024; 11:ENEURO.0344-23.2023. [PMID: 38413199 PMCID: PMC10972738 DOI: 10.1523/eneuro.0344-23.2023] [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: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 02/29/2024] Open
Abstract
Dopamine system dysfunction, observed in animal models with psychosis-like symptomatology, can be restored by targeting Gamma-Aminobutyric Acid type A receptors (GABAAR) containing the α5, but not α1, subunit in the ventral hippocampus (vHipp). The reason for this discrepancy in efficacy remains elusive; however, one key difference is that α1GABAARs are primarily located in the synapse, whereas α5GABAARs are mostly extrasynaptic. To test whether receptor location is responsible for this difference in efficacy, we injected a small interfering ribonucleic acid (siRNA) into the vHipp to knock down radixin, a scaffolding protein that holds α5GABAARs in the extrasynaptic space. We then administered GL-II-73, a positive allosteric modulator of α5GABAARs (α5-PAM) known to reverse shock-induced deficits in dopamine system function, to determine if shifting α5GABAARs from the extrasynaptic space to the synapse would prevent the effects of α5-PAM on dopamine system function. As expected, knockdown of radixin significantly decreased radixin-associated α5GABAARs and increased the proportion of synaptic α5GABAARs, without changing the overall expression of α5GABAARs. Importantly, GL-II-73 was no longer able to modulate dopamine neuron activity in radixin-knockdown rats, indicating that the extrasynaptic localization of α5GABAARs is critical for hippocampal modulation of the dopamine system. These results may have important implications for clinical use of GL-II-73, as periods of high hippocampal activity appear to favor synaptic α5GABAARs, thus efficacy may be diminished in conditions where aberrant hippocampal activity is present.Significance Statement Currently available treatments for psychosis, a debilitating symptom linked with several brain disorders, are inadequate. While they can help manage symptoms in some patients, they do so imperfectly. They are also associated with severe side effects that can cause discontinuation of medication. This study provides preclinical evidence that the drug, GL-II-73, possesses the ability to modulate dopamine activity, a key player in psychosis symptoms, and further provides some mechanistic details regarding these effects. Overall, this work contributes to the growing body of literature suggesting that GL-II-73 and similar compounds may possess antipsychotic efficacy.
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Affiliation(s)
- Alexandra M. McCoy
- Department of Pharmacology and Center for Biomedical Neuroscience, UT Health San Antonio, San Antonio, Texas 78229
- South Texas Veterans Health Care System, Audie L. Murphy Division, San Antonio, Texas 78229
| | - Thomas D. Prevot
- Campbell Family Mental Health Research Institute of CAMH, Toronto, Ontario M5G 2C1, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario M5S 1A1, Canada
| | - Md Yeunus Mian
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211
| | - Dishary Sharmin
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211
| | - Adeeba N. Ahmad
- University of Texas, Rio Grande Valley, Edinburg, Texas 78539
| | - James M. Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211
| | - Etienne L. Sibille
- Campbell Family Mental Health Research Institute of CAMH, Toronto, Ontario M5G 2C1, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario M5S 1A1, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S 1A1, Canada
| | - Daniel J. Lodge
- Department of Pharmacology and Center for Biomedical Neuroscience, UT Health San Antonio, San Antonio, Texas 78229
- South Texas Veterans Health Care System, Audie L. Murphy Division, San Antonio, Texas 78229
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Wan C, Song X, Zhang Z, Hu W, Chen Y, Sun W, Liu Z, Wang S, Meng W. Voluntary exercise during puberty promotes spatial memory and hippocampal DG/CA3 synaptic transmission in mice. Cereb Cortex 2024; 34:bhad497. [PMID: 38124544 DOI: 10.1093/cercor/bhad497] [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: 10/08/2023] [Revised: 12/01/2023] [Accepted: 12/03/2023] [Indexed: 12/23/2023] Open
Abstract
Physical exercise has been shown to have an impact on memory and hippocampal function across different age groups. Nevertheless, the influence and mechanisms underlying how voluntary exercise during puberty affects memory are still inadequately comprehended. This research aims to examine the impacts of self-initiated physical activity throughout adolescence on spatial memory. Developing mice were exposed to a 4-wk voluntary wheel running exercise protocol, commencing at the age of 30 d. After engaging in voluntary wheel running exercise during development, there was an enhancement in spatial memory. Moreover, hippocampal dentate gyrus and CA3 neurons rather than CA1 neurons exhibited an increase in the miniature excitatory postsynaptic currents and miniature inhibitory postsynaptic currents. In addition, there was an increase in the expression of NR2A/NR2B subunits of N-methyl-D-aspartate receptors and α1GABAA subunit of gamma-aminobutyric acid type A receptors, as well as dendritic spine density, specifically within dentate gyrus and CA3 regions rather than CA1 region. The findings suggest that voluntary exercise during development can enhance spatial memory in mice by increasing synapse numbers and improving synaptic transmission in hippocampal dentate gyrus and CA3 regions, but not in CA1 region. This study sheds light on the neural mechanisms underlying how early-life exercise improves cognitive function.
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Affiliation(s)
- Changjian Wan
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Xueqing Song
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Zhuyu Zhang
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Wenxiang Hu
- School of Life Sciences, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 33001, China
| | - Yanhua Chen
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Wei Sun
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Zhibin Liu
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Songhua Wang
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Wei Meng
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
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Nuwer JL, Povysheva N, Jacob TC. Long-term α5 GABA A receptor negative allosteric modulator treatment reduces NMDAR-mediated neuronal excitation and maintains basal neuronal inhibition. Neuropharmacology 2023; 237:109587. [PMID: 37270156 PMCID: PMC10527172 DOI: 10.1016/j.neuropharm.2023.109587] [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: 03/27/2023] [Revised: 04/27/2023] [Accepted: 05/09/2023] [Indexed: 06/05/2023]
Abstract
α5 subunit-containing GABA type-A receptors (α5 GABAARs) are enriched in the hippocampus and play critical roles in neurodevelopment, synaptic plasticity, and cognition. α5 GABAAR preferring negative allosteric modulators (α5 NAMs) show promise mitigating cognitive impairment in preclinical studies of conditions characterized by excess GABAergic inhibition, including Down syndrome and memory deficits post-anesthesia. However, previous studies have primarily focused on acute application or single-dose α5 NAM treatment. Here, we measured the effects of chronic (7-day) in vitro treatment with L-655,708 (L6), a highly selective α5 NAM, on glutamatergic and GABAergic synapses in rat hippocampal neurons. We previously showed that 2-day in vitro treatment with L6 enhanced synaptic levels of the glutamate NMDA receptor (NMDAR) GluN2A subunit without modifying surface α5 GABAAR expression, inhibitory synapse function, or L6 sensitivity. We hypothesized that chronic L6 treatment would further increase synaptic GluN2A subunit levels while maintaining GABAergic inhibition and L6 efficacy, thus increasing neuronal excitation and glutamate-evoked intracellular calcium responses. Immunofluorescence experiments revealed that 7-day L6 treatment slightly increased the synaptic levels of gephyrin and surface α5 GABAARs. Functional studies showed that chronic α5 NAM treatment did not alter inhibition or α5 NAM sensitivity. Surprisingly, chronic L6 exposure decreased surface levels of GluN2A and GluN2B subunits, concurrent with reduced NMDAR-mediated neuronal excitation as seen by faster synaptic decay rates and reduced glutamate-evoked calcium responses. Together, these results show that chronic in vitro treatment with an α5 NAM leads to subtle homeostatic changes in inhibitory and excitatory synapses that suggest an overall dampening of excitability.
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Affiliation(s)
- Jessica L Nuwer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nadya Povysheva
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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Ariza A, Naeini SM, Khodaei S, Ba J, Wang DS, Orser BA. Cell-surface biotinylation of GABA A receptors in mouse hippocampal slices after sevoflurane anesthesia. STAR Protoc 2023; 4:102450. [PMID: 37480561 PMCID: PMC10382930 DOI: 10.1016/j.xpro.2023.102450] [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: 02/06/2023] [Revised: 05/12/2023] [Accepted: 06/19/2023] [Indexed: 07/24/2023] Open
Abstract
Here, we present a protocol for studying the cell-surface proteins in hippocampal slices after in vivo administration of sevoflurane, an inhaled general anesthetic drug, to mice. We describe steps for anesthetic delivery, hippocampal slice preparation, and cell-surface biotinylation. We then detail the isolation of surface proteins and their quantification through Western blotting. This protocol can be adapted to study changes in other surface proteins following exposure to various general anesthetic drugs. For complete details on the use and execution of this protocol, please refer to Wang et al. (2012),1 Zurek et al. (2014),2 and Yu et al. (2019).3.
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Affiliation(s)
- Anthony Ariza
- Department of Physiology, University of Toronto, Toronto, ON, Canada.
| | | | - Shahin Khodaei
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Joycelyn Ba
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Dian-Shi Wang
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Beverley Anne Orser
- Department of Physiology, University of Toronto, Toronto, ON, Canada; Department of Anesthesiology & Pain Medicine, University of Toronto, Toronto, ON, Canada; Department of Anesthesia, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
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Kaplan K, Hunsberger HC. Benzodiazepine-induced anterograde amnesia: detrimental side effect to novel study tool. Front Pharmacol 2023; 14:1257030. [PMID: 37781704 PMCID: PMC10536168 DOI: 10.3389/fphar.2023.1257030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 09/04/2023] [Indexed: 10/03/2023] Open
Abstract
Benzodiazepines (BZDs) are anxiolytic drugs that act on GABAa receptors and are used to treat anxiety disorders. However, these drugs come with the detrimental side effect of anterograde amnesia, or the inability to form new memories. In this review we discuss, behavioral paradigms, sex differences and hormonal influences affecting BZD-induced amnesia, molecular manipulations, including the knockout of GABAa receptor subunits, and regional studies utilizing lesion and microinjection techniques targeted to the hippocampus and amygdala. Additionally, the relationship between BZD use and cognitive decline related to Alzheimer's disease is addressed, as there is a lack of consensus on whether these drugs are involved in inducing or accelerating pathological cognitive deficits. This review aims to inspire new research directions, as there is a gap in knowledge in understanding the cellular and molecular mechanisms behind BZD-induced amnesia. Understanding these mechanisms will allow for the development of alternative treatments and potentially allow BZDs to be used as a novel tool to study Alzheimer's disease.
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Affiliation(s)
- Kameron Kaplan
- Center for Neurodegenerative Diseases and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, The Chicago Medical School, North Chicago, IL, United States
| | - Holly Christian Hunsberger
- Center for Neurodegenerative Diseases and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, The Chicago Medical School, North Chicago, IL, United States
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12
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Patt L, Tascio D, Domingos C, Timmermann A, Jabs R, Henneberger C, Steinhäuser C, Seifert G. Impact of Developmental Changes of GABA A Receptors on Interneuron-NG2 Glia Transmission in the Hippocampus. Int J Mol Sci 2023; 24:13490. [PMID: 37686294 PMCID: PMC10488269 DOI: 10.3390/ijms241713490] [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: 06/22/2023] [Revised: 08/11/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
NG2 glia receive synaptic input from neurons, but the functional impact of this glial innervation is not well understood. In the developing cerebellum and somatosensory cortex the GABAergic input might regulate NG2 glia differentiation and myelination, and a switch from synaptic to extrasynaptic neuron-glia signaling was reported in the latter region. Myelination in the hippocampus is sparse, and most NG2 glia retain their phenotype throughout adulthood, raising the question of the properties and function of neuron-NG2 glia synapses in that brain region. Here, we compared spontaneous and evoked GABAA receptor-mediated currents of NG2 glia in juvenile and adult hippocampi of mice of either sex and assessed the mode of interneuron-glial signaling changes during development. With patch-clamp and pharmacological analyses, we found a decrease in innervation of hippocampal NG2 glia between postnatal days 10 and 60. At the adult stage, enhanced activation of extrasynaptic receptors occurred, indicating a spillover of GABA. This switch from synaptic to extrasynaptic receptor activation was accompanied by downregulation of γ2 and upregulation of the α5 subunit. Molecular analyses and high-resolution expansion microscopy revealed mechanisms of glial GABAA receptor trafficking and clustering. We found that gephyrin and radixin are organized in separate clusters along glial processes. Surprisingly, the developmental loss of γ2 and postsynaptic receptors were not accompanied by altered glial expression of scaffolding proteins, auxiliary receptor subunits or postsynaptic interaction proteins. The GABAergic input to NG2 glia might contribute to the release of neurotrophic factors from these cells and influence neuronal synaptic plasticity.
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Affiliation(s)
- Linda Patt
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Dario Tascio
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Catia Domingos
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Aline Timmermann
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Ronald Jabs
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Christian Henneberger
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Gerald Seifert
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
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13
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McCoy AM, Prevot TD, Mian MY, Sharmin D, Ahmad AN, Cook JM, Sibille EL, Lodge DJ. Extrasynaptic localization is essential for α5GABA A receptor modulation of dopamine system function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548744. [PMID: 37502875 PMCID: PMC10370028 DOI: 10.1101/2023.07.12.548744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Dopamine system dysfunction, observed in animal models with psychosis-like symptomatology, can be restored by targeting Gamma-Aminobutyric Acid type A receptors (GABA A R) containing the α5, but not α1, subunit in the ventral hippocampus (vHipp). The reason for this discrepancy in efficacy remains elusive; however, one key difference is that α1GABA A Rs are primarily located in the synapse, whereas α5GABA A Rs are mostly extrasynaptic. To test whether receptor location is responsible for this difference in efficacy, we injected a small interfering ribonucleic acid (siRNA) into the vHipp to knock down radixin, a scaffolding protein that holds α5GABA A Rs in the extrasynaptic space. We then administered GL-II-73, a positive allosteric modulator of α5GABA A Rs (α5-PAM) known to reverse shock-induced deficits in dopamine system function, to determine if shifting α5GABA A Rs from the extrasynaptic space to the synapse would prevent the effects of α5-PAM on dopamine system function. As expected, knockdown of radixin significantly decreased radixin-associated α5GABA A Rs and increased the proportion of synaptic α5GABA A Rs, without changing the overall expression of α5GABA A Rs. Importantly, GL-II-73 was no longer able to modulate dopamine neuron activity in radixin-knockdown rats, indicating that the extrasynaptic localization of α5GABA A Rs is critical for hippocampal modulation of the dopamine system. These results may have important implications for clinical use of GL-II-73, as periods of high hippocampal activity appear to favor synaptic α5GABA A Rs, thus efficacy may be diminished in conditions where aberrant hippocampal activity is present. Significance Statement Dopamine activity is known to be altered in both psychosis patients and in animal models, with promising new antipsychotics restoring normal dopamine system function. One such drug is GL-II-73, a positive allosteric modulator of α5GABA A Rs (α5-PAM). Interestingly, previous research has shown that a positive allosteric modulator of α1GABA A Rs (α1-PAM) does not share this ability, even when directly given to the ventral hippocampus, a region known to modulate dopamine activity. One potential explanation for this difference we examined in this study is that α1GABA A Rs are primarily located in the synapse, whereas α5GABA A Rs are mostly extrasynaptic. Determining the mechanism of this differential efficacy could lead to the refinement of antipsychotic treatment and improve patient outcomes overall.
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14
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Yu X, Gao Z, Gao M, Qiao M. Bibliometric Analysis on GABA-A Receptors Research Based on CiteSpace and VOSviewer. J Pain Res 2023; 16:2101-2114. [PMID: 37361426 PMCID: PMC10289248 DOI: 10.2147/jpr.s409380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/11/2023] [Indexed: 06/28/2023] Open
Abstract
Background GABA-A receptors are the primary mediators of brain inhibitory neurotransmission. In the past years, many studies focused on this channel to decipher the pathogenesis of related diseases but lacked bibliometric analysis research. This study aims to explore the research status and identify the research trends of GABA-A receptor channels. Methods Publications related to GABA-A receptor channels were retrieved from the Web of Science Core Collection from 2012 to 2022. After screening, the VOSviewer 1.6.18 and Citespace 5.8 R3 were used for bibliometric analysis from journals, countries, institutions, authors, co-cited references and keywords. Results We included 12,124 publications in the field of GABA-A receptor channels for analysis. The data shows that although there was a slight decrease in annual publications from 2012 to 2021, it remained at a relatively high level. Most publications were in the domain of neuroscience. Additionally, the United States was the most prolific country, followed by China. Univ Toronto was the most productive institution, and James M Cook led essential findings in this field. Furthermore, brain activation, GABAAR subunits expression, modulation mechanism in pain and anxiety behaviors and GABA and dopamine were paid attention to by researchers. And top research frontiers were molecular docking, autoimmune encephalitic series, obesity, sex difference, diagnosis and management, EEG and KCC2. Conclusion Taken together, academic attention on GABA-A receptor channels was never neglected since 2012. Our analysis identified key information, such as core countries, institutions and authors in this field. Molecular docking, autoimmune encephalitic series, obesity, sex difference, diagnosis and management, EEG and KCC2 will be the future research direction.
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Affiliation(s)
- Xufeng Yu
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong Province, People’s Republic of China
| | - Zhan Gao
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong Province, People’s Republic of China
| | - Mingzhou Gao
- Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong Province, People’s Republic of China
| | - Mingqi Qiao
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong Province, People’s Republic of China
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15
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Ebstein F, Küry S, Most V, Rosenfelt C, Scott-Boyer MP, van Woerden GM, Besnard T, Papendorf JJ, Studencka-Turski M, Wang T, Hsieh TC, Golnik R, Baldridge D, Forster C, de Konink C, Teurlings SM, Vignard V, van Jaarsveld RH, Ades L, Cogné B, Mignot C, Deb W, Jongmans MC, Sessions Cole F, van den Boogaard MJH, Wambach JA, Wegner DJ, Yang S, Hannig V, Brault JA, Zadeh N, Bennetts B, Keren B, Gélineau AC, Powis Z, Towne M, Bachman K, Seeley A, Beck AE, Morrison J, Westman R, Averill K, Brunet T, Haasters J, Carter MT, Osmond M, Wheeler PG, Forzano F, Mohammed S, Trakadis Y, Accogli A, Harrison R, Guo Y, Hakonarson H, Rondeau S, Baujat G, Barcia G, Feichtinger RG, Mayr JA, Preisel M, Laumonnier F, Kallinich T, Knaus A, Isidor B, Krawitz P, Völker U, Hammer E, Droit A, Eichler EE, Elgersma Y, Hildebrand PW, Bolduc F, Krüger E, Bézieau S. PSMC3 proteasome subunit variants are associated with neurodevelopmental delay and type I interferon production. Sci Transl Med 2023; 15:eabo3189. [PMID: 37256937 PMCID: PMC10506367 DOI: 10.1126/scitranslmed.abo3189] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 05/10/2023] [Indexed: 06/02/2023]
Abstract
A critical step in preserving protein homeostasis is the recognition, binding, unfolding, and translocation of protein substrates by six AAA-ATPase proteasome subunits (ATPase-associated with various cellular activities) termed PSMC1-6, which are required for degradation of proteins by 26S proteasomes. Here, we identified 15 de novo missense variants in the PSMC3 gene encoding the AAA-ATPase proteasome subunit PSMC3/Rpt5 in 23 unrelated heterozygous patients with an autosomal dominant form of neurodevelopmental delay and intellectual disability. Expression of PSMC3 variants in mouse neuronal cultures led to altered dendrite development, and deletion of the PSMC3 fly ortholog Rpt5 impaired reversal learning capabilities in fruit flies. Structural modeling as well as proteomic and transcriptomic analyses of T cells derived from patients with PSMC3 variants implicated the PSMC3 variants in proteasome dysfunction through disruption of substrate translocation, induction of proteotoxic stress, and alterations in proteins controlling developmental and innate immune programs. The proteostatic perturbations in T cells from patients with PSMC3 variants correlated with a dysregulation in type I interferon (IFN) signaling in these T cells, which could be blocked by inhibition of the intracellular stress sensor protein kinase R (PKR). These results suggest that proteotoxic stress activated PKR in patient-derived T cells, resulting in a type I IFN response. The potential relationship among proteosome dysfunction, type I IFN production, and neurodevelopment suggests new directions in our understanding of pathogenesis in some neurodevelopmental disorders.
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Affiliation(s)
- Frédéric Ebstein
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
| | - Sébastien Küry
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France
- Nantes Université, CHU Nantes, CNRS, INSERM, l’institut du thorax, 44000 Nantes, France
| | - Victoria Most
- Institut für Medizinische Physik und Biophysik, Universität Leipzig, Medizinische Fakultät, Härtelstr. 16-18, 04107 Leipzig, Germany
| | - Cory Rosenfelt
- Department of Pediatrics, University of Alberta, Edmonton, AB CT6G 1C9, Canada
| | | | - Geeske M. van Woerden
- Department of Neuroscience, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
- ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
| | - Thomas Besnard
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France
- Nantes Université, CHU Nantes, CNRS, INSERM, l’institut du thorax, 44000 Nantes, France
| | - Jonas Johannes Papendorf
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
| | - Maja Studencka-Turski
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
| | - Tianyun Wang
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA
- Department of Medical Genetics, Center for Medical Genetics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
- Neuroscience Research Institute, Peking University; Key Laboratory for Neuroscience, Ministry of Education of China & National Health Commission of China, Beijing 100191, China
| | - Tzung-Chien Hsieh
- Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, Germany
| | - Richard Golnik
- Klinik für Pädiatrie I, Universitätsklinikum Halle (Saale), 06120 Halle (Saale)
| | - Dustin Baldridge
- The Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63130-4899, USA
| | - Cara Forster
- GeneDx, 207 Perry Parkway, Gaithersburg, MD 20877, USA
| | - Charlotte de Konink
- Department of Neuroscience, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
- ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
| | - Selina M.W. Teurlings
- Department of Neuroscience, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
- ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
| | - Virginie Vignard
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France
- Nantes Université, CHU Nantes, CNRS, INSERM, l’institut du thorax, 44000 Nantes, France
| | | | - Lesley Ades
- Department of Clinical Genetics, The Children’s Hospital at Westmead, Locked Bag 4001, Westmead, NSW, 2145, Australia
- Disciplines of Genomic Medicine & Child and Adolescent Health, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, 2145, Australia
| | - Benjamin Cogné
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France
- Nantes Université, CHU Nantes, CNRS, INSERM, l’institut du thorax, 44000 Nantes, France
| | - Cyril Mignot
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», 75013 Paris, France
- Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Inserm U1127, CNRS UMR 7225, 75013, Paris, France
| | - Wallid Deb
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France
- Nantes Université, CHU Nantes, CNRS, INSERM, l’institut du thorax, 44000 Nantes, France
| | - Marjolijn C.J. Jongmans
- Department of Genetics, University Medical Center Utrecht, 3508 AB, Utrecht, The Netherlands
- Princess Máxima Center for Pediatric Oncology, 3584 CS, Utrecht, The Netherlands
| | - F. Sessions Cole
- The Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63130-4899, USA
| | | | - Jennifer A. Wambach
- The Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63130-4899, USA
| | - Daniel J. Wegner
- The Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63130-4899, USA
| | - Sandra Yang
- GeneDx, 207 Perry Parkway, Gaithersburg, MD 20877, USA
| | - Vickie Hannig
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jennifer Ann Brault
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Neda Zadeh
- Genetics Center, Orange, CA 92868, USA; Division of Medical Genetics, Children’s Hospital of Orange County, Orange, CA 92868, USA
| | - Bruce Bennetts
- Disciplines of Genomic Medicine & Child and Adolescent Health, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, 2145, Australia
- Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW, 2145, Australia
| | - Boris Keren
- Département de Génétique, Centre de Référence des Déficiences Intellectuelles de Causes Rares, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, 75013 Paris
| | - Anne-Claire Gélineau
- Département de Génétique, Centre de Référence des Déficiences Intellectuelles de Causes Rares, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, 75013 Paris
| | - Zöe Powis
- Department of Clinical Research, Ambry Genetics, Aliso Viejo, CA 92656, USA
| | - Meghan Towne
- Department of Clinical Research, Ambry Genetics, Aliso Viejo, CA 92656, USA
| | | | - Andrea Seeley
- Genomic Medicine Institute, Geisinger, Danville, PA 17822, USA
| | - Anita E. Beck
- Department of Pediatrics, Division of Genetic Medicine, University of Washington & Seattle Children’s Hospital, Seattle, WA 98195-6320, USA
| | - Jennifer Morrison
- Division of Genetics, Arnold Palmer Hospital for Children, Orlando Health, Orlando, FL 32806, USA
| | - Rachel Westman
- Division of Genetics, St. Luke’s Clinic, Boise, ID 83712, USA
| | - Kelly Averill
- Department of Pediatrics, Division of Pediatric Neurology, UT Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Theresa Brunet
- Institute of Human Genetics, Technical University of Munich, School of Medicine, 81675 Munich, Germany
- Institute of Neurogenomics (ING), Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Judith Haasters
- Klinikum der Universität München, Integriertes Sozial- pädiatrisches Zentrum, 80337 Munich, Germany
| | - Melissa T. Carter
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, ON K1H 8L1, Canada
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, ON K1H 8L1, Canada
| | - Matthew Osmond
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, ON K1H 8L1, Canada
| | - Patricia G. Wheeler
- Division of Genetics, Arnold Palmer Hospital for Children, Orlando Health, Orlando, FL 32806, USA
| | - Francesca Forzano
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Clinical Genetics Department, Guy’s & St Thomas’ NHS Foundation Trust, London SE1 9RT, UK
| | - Shehla Mohammed
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Clinical Genetics Department, Guy’s & St Thomas’ NHS Foundation Trust, London SE1 9RT, UK
| | - Yannis Trakadis
- Division of Medical Genetics, McGill University Health Centre, Montreal, QC H4A 3J1, Canada
| | - Andrea Accogli
- Division of Medical Genetics, McGill University Health Centre, Montreal, QC H4A 3J1, Canada
| | - Rachel Harrison
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Department of Clinical Genetics, Nottingham University Hospitals NHS Trust, City Hospital Campus, The Gables, Gate 3, Hucknall Road, Nottingham NG5 1PB, UK
| | - Yiran Guo
- Center for Applied Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Center for Data Driven Discovery in Biomedicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19146, USA
| | - Hakon Hakonarson
- Center for Applied Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sophie Rondeau
- Service de Médecine Génomique des Maladies Rares, Hôpital Universitaire Necker-Enfants Malades, 75743 Paris, France
| | - Geneviève Baujat
- Service de Médecine Génomique des Maladies Rares, Hôpital Universitaire Necker-Enfants Malades, 75743 Paris, France
| | - Giulia Barcia
- Service de Médecine Génomique des Maladies Rares, Hôpital Universitaire Necker-Enfants Malades, 75743 Paris, France
| | - René Günther Feichtinger
- University Children’s Hospital, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Johannes Adalbert Mayr
- University Children’s Hospital, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Martin Preisel
- University Children’s Hospital, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Frédéric Laumonnier
- UMR 1253, iBrain, Université de Tours, Inserm, 37032 Tours, France
- Service de Génétique, Centre Hospitalier Régional Universitaire, 37032 Tours, France
| | - Tilmann Kallinich
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité Universitätsmedizin Berlin; 13353 Berlin, Germany
- Deutsches Rheumaforschungszentrum, An Institute of the Leibniz Association, Berlin and Berlin Institute of Health, 10117 Berlin, Germany
| | - Alexej Knaus
- Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, Germany
| | - Bertrand Isidor
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France
- Nantes Université, CHU Nantes, CNRS, INSERM, l’institut du thorax, 44000 Nantes, France
| | - Peter Krawitz
- Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, Germany
| | - Uwe Völker
- Universitätsmedizin Greifswald, Interfakultäres Institut für Genetik und Funktionelle Genomforschung, Abteilung für Funktionelle Genomforschung, 17487 Greifswald, Germany
| | - Elke Hammer
- Universitätsmedizin Greifswald, Interfakultäres Institut für Genetik und Funktionelle Genomforschung, Abteilung für Funktionelle Genomforschung, 17487 Greifswald, Germany
| | - Arnaud Droit
- Research Center of Quebec CHU-Université Laval, Québec, QC PQ G1E6W2, Canada
| | - Evan E. Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98195, USA
| | - Ype Elgersma
- ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
| | - Peter W. Hildebrand
- Institut für Medizinische Physik und Biophysik, Universität Leipzig, Medizinische Fakultät, Härtelstr. 16-18, 04107 Leipzig, Germany
- Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
- Berlin Institute of Health, 10178 Berlin, Germany
| | - François Bolduc
- Department of Pediatrics, University of Alberta, Edmonton, AB CT6G 1C9, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Elke Krüger
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
| | - Stéphane Bézieau
- Nantes Université, CHU Nantes, Service de Génétique Médicale, 44000 Nantes, France
- Nantes Université, CHU Nantes, CNRS, INSERM, l’institut du thorax, 44000 Nantes, France
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16
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Mao R, Xu S, Sun G, Yu Y, Zuo Z, Wang Y, Yang K, Zhang Z, Yang W. Triptolide injection reduces Alzheimer's disease-like pathology in mice. Synapse 2023; 77:e22261. [PMID: 36633502 DOI: 10.1002/syn.22261] [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: 03/24/2022] [Revised: 12/21/2022] [Accepted: 01/08/2023] [Indexed: 01/13/2023]
Abstract
Triptolide is an epoxidized diterpene lactone isolated from Tripterygium wilfordii. Studies have shown that triptolide exerts organ-protective effects. However, it remains unknown whether triptolide improves Alzheimer's disease (AD)-like presentations. Thirty healthy 8-week-old male C57BL/6J mice were randomly divided into control (n = 10), model (n = 10), and triptolide (n = 10) groups. Amyloid-β (Aβ)42 was injected bilaterally into the ventricles of mice in the model group. Triptolide was injected intraperitoneally daily after injecting Aβ42 (a total of 30 days) in the triptolide group. Learning and memory were tested using the Morris water maze test. The deposition of Aβ42 in the hippocampus was detected using immunohistochemical staining. In the hippocampus, three synaptic-associated proteins-gephyrin, collybistin, and GABRA1 -were detected by western blotting. Furthermore, we used ELISA to detect proinflammatory cytokines, including TNF-α and IL-1β, in the blood and hippocampus. Moreover, superoxide dismutase (SOD), malondialdehyde (MDA), and GSH levels were measured using the corresponding kits. We found that triptolide improved spatial learning and memory in AD-like mice. Additionally, triptolide maintained the expression of gephyrin, collybistin, and GABRA1 and reduced Aβ in these mice. Additionally, triptolide reduced the expression of inflammatory cytokines and decreased oxidative damage in AD-like mice. Our study suggests that triptolide attenuates AD-like changes in the mouse brain.
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Affiliation(s)
- Rui Mao
- Department of Neurology, Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Shiyan, Hubei, China
| | - Shihao Xu
- Department of Neurology, Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Shiyan, Hubei, China
| | - Guangwen Sun
- Department of Neurology, Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Shiyan, Hubei, China
- Department of Neurology, Sinopharm Dongfeng General Hospital, Jinzhou Medical University Union Training Base, Jinzhou, China
| | - Yingying Yu
- Department of Neurology, Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Shiyan, Hubei, China
- Department of Neurology, Sinopharm Dongfeng General Hospital, Jinzhou Medical University Union Training Base, Jinzhou, China
| | - Zhiyi Zuo
- Department of Anesthesiology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Yuanyuan Wang
- Department of Neurology, Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Shiyan, Hubei, China
| | - Kun Yang
- Department of Anesthesiology, Sinopharm Dongfeng General Hospital, Jinzhou Medical University Union Training Base, Jinzhou, China
| | - Zhen Zhang
- Department of Orthopedics, Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Shiyan, Hubei, China
| | - Wenqiong Yang
- Department of Neurology, Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Shiyan, Hubei, China
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17
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Pharmacological Signature and Target Specificity of Inhibitory Circuits Formed by Martinotti Cells in the Mouse Barrel Cortex. J Neurosci 2023; 43:14-27. [PMID: 36384682 PMCID: PMC9838699 DOI: 10.1523/jneurosci.1661-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/13/2022] [Accepted: 10/26/2022] [Indexed: 11/18/2022] Open
Abstract
In the neocortex, fast synaptic inhibition orchestrates both spontaneous and sensory-evoked activity. GABAergic interneurons (INs) inhibit pyramidal neurons (PNs) directly, modulating their output activity and thus contributing to balance cortical networks. Moreover, several IN subtypes also inhibit other INs, forming specific disinhibitory circuits, which play crucial roles in several cognitive functions. Here, we studied a subpopulation of somatostatin-positive INs, the Martinotti cells (MCs) in layer 2/3 of the mouse barrel cortex (both sexes). MCs inhibit the distal portion of PN apical dendrites, thus controlling dendrite electrogenesis and synaptic integration. Yet, it is poorly understood whether MCs inhibit other elements of the cortical circuits, and the connectivity properties with non-PN targets are unknown. We found that MCs have a strong preference for PN dendrites, but they also considerably connect with parvalbumin-positive, vasoactive intestinal peptide-expressing, and layer 1 (L1) INs. Remarkably, GABAergic synapses from MCs exhibited clear cell type-specific short-term plasticity. Moreover, whereas the biophysical properties of MC-PN synapses were consistent with distal dendritic inhibition, MC-IN synapses exhibited characteristics of fast perisomatic inhibition. Finally, MC-PN connections used α5-containing GABAA receptors (GABAARs), but this subunit was not expressed by the other INs targeted by MCs. We reveal a specialized connectivity blueprint of MCs within different elements of superficial cortical layers. In addition, our results identify α5-GABAARs as the molecular fingerprint of MC-PN dendritic inhibition. This is of critical importance, given the role of α5-GABAARs in cognitive performance and their involvement in several brain diseases.SIGNIFICANCE STATEMENT Martinotti cells (MCs) are a prominent, broad subclass of somatostatin-expressing GABAergic interneurons, specialized in controlling distal dendrites of pyramidal neurons (PNs) and taking part in several cognitive functions. Here we characterize the connectivity pattern of MCs with other interneurons in the superficial layers (L1 and L2/3) of the mouse barrel cortex. We found that the connectivity pattern of MCs with PNs as well as parvalbumin, vasoactive intestinal peptide, and L1 interneurons exhibit target-specific plasticity and biophysical properties. The specificity of α5-GABAARs at MC-PN synapses and the lack or functional expression of this subunit by other cell types define the molecular identity of MC-PN connections and the exclusive involvement of this inhibitory circuits in α5-dependent cognitive tasks.
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18
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Quantifying postsynaptic receptor dynamics: insights into synaptic function. Nat Rev Neurosci 2023; 24:4-22. [PMID: 36352031 DOI: 10.1038/s41583-022-00647-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2022] [Indexed: 11/11/2022]
Abstract
The molecular composition of presynaptic and postsynaptic neuronal terminals is dynamic, and yet long-term stabilizations in postsynaptic responses are necessary for synaptic development and long-term plasticity. The need to reconcile these concepts is further complicated by learning- and memory-related plastic changes in the molecular make-up of synapses. Advances in single-particle tracking mean that we can now quantify the number and diffusive properties of specific synaptic molecules, while statistical thermodynamics provides a framework to analyse these molecular fluctuations. In this Review, we discuss the use of these approaches to gain quantitative descriptions of the processes underlying the turnover, long-term stability and plasticity of postsynaptic receptors and show how these can help us to understand the balance between local molecular turnover and synaptic structural identity and integrity.
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19
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Zegarra-Valdivia J, Fernandez AM, Martinez-Rachadell L, Herrero-Labrador R, Fernandes J, Torres Aleman I. Insulin and insulin-like growth factor-I receptors in astrocytes exert different effects on behavior and Alzheimer´s-like pathology. F1000Res 2022; 11:663. [PMID: 36636477 PMCID: PMC9823242 DOI: 10.12688/f1000research.121901.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
Background: Pleiotropic actions of insulin and insulin-like growth factor I (IGF-I) in the brain are context- and cell-dependent, but whether this holds for their receptors (insulin receptor (IR) and IGF-I receptor (IGF-IR), respectively), is less clear. Methods: We compared mice lacking IR or IGF-IR in glial fibrillary astrocytic protein (GFAP)-expressing astrocytes in a tamoxifen-regulated manner, to clarify their role in this type of glial cells, as the majority of data of their actions in brain have been obtained in neurons. Results: We observed that mice lacking IR in GFAP astrocytes (GFAP IR KO mice) develop mood disturbances and maintained intact cognition, while at the same time show greater pathology when cross-bred with APP/PS1 mice, a model of familial Alzheimer´s disease (AD). Conversely, mice lacking IGF-IR in GFAP astrocytes (GFAP-IGF-IR KO mice) show cognitive disturbances, maintained mood tone, and show control-dependent changes in AD-like pathology. Conclusions: These observations confirm that the role of IR and IGF-IR in the brain is cell-specific and context-dependent.
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Affiliation(s)
- Jonathan Zegarra-Valdivia
- Achucarro Basque Center for Neuroscience, Leioa, Bizkaia, 48940, Spain,Cajal Institute, Madrid, 28002, Spain,CIBERNED, Madrid, Spain,Universidad Señor de Sipán, Chiclayo, Peru
| | | | | | | | - Jansen Fernandes
- Cajal Institute, Madrid, 28002, Spain,Universidade Federal São Paulo, São Paulo, Brazil
| | - Ignacio Torres Aleman
- Achucarro Basque Center for Neuroscience, Leioa, Bizkaia, 48940, Spain,CIBERNED, Madrid, Spain,Ikerbasque Foundation for Science, Bilbao, Spain,
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20
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Hausrat TJ, Vogl C, Neef J, Schweizer M, Yee BK, Strenzke N, Kneussel M. Monoallelic loss of the F-actin-binding protein radixin facilitates startle reactivity and pre-pulse inhibition in mice. Front Cell Dev Biol 2022; 10:987691. [DOI: 10.3389/fcell.2022.987691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/11/2022] [Indexed: 11/29/2022] Open
Abstract
Hearing impairment is one of the most common disorders with a global burden and increasing prevalence in an ever-aging population. Previous research has largely focused on peripheral sensory perception, while the brain circuits of auditory processing and integration remain poorly understood. Mutations in the rdx gene, encoding the F-actin binding protein radixin (Rdx), can induce hearing loss in human patients and homozygous depletion of Rdx causes deafness in mice. However, the precise physiological function of Rdx in hearing and auditory information processing is still ill-defined. Here, we investigated consequences of rdx monoallelic loss in the mouse. Unlike the homozygous (−/−) rdx knockout, which is characterized by the degeneration of actin-based stereocilia and subsequent hearing loss, our analysis of heterozygous (+/−) mutants has revealed a different phenotype. Specifically, monoallelic loss of rdx potentiated the startle reflex in response to acoustic stimulation of increasing intensities, suggesting a gain of function relative to wildtype littermates. The monoallelic loss of the rdx gene also facilitated pre-pulse inhibition of the acoustic startle reflex induced by weak auditory pre-pulse stimuli, indicating a modification to the circuit underlying sensorimotor gating of auditory input. However, the auditory brainstem response (ABR)-based hearing thresholds revealed a mild impairment in peripheral sound perception in rdx (+/-) mice, suggesting minor aberration of stereocilia structural integrity. Taken together, our data suggest a critical role of Rdx in the top-down processing and/or integration of auditory signals, and therefore a novel perspective to uncover further Rdx-mediated mechanisms in central auditory information processing.
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21
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Sleep and wake cycles dynamically modulate hippocampal inhibitory synaptic plasticity. PLoS Biol 2022; 20:e3001812. [PMID: 36318572 PMCID: PMC9624398 DOI: 10.1371/journal.pbio.3001812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/30/2022] [Indexed: 01/01/2023] Open
Abstract
Sleep is an essential process that consolidates memories by modulating synapses through poorly understood mechanisms. Here, we report that GABAergic synapses in hippocampal CA1 pyramidal neurons undergo daily rhythmic alterations. Specifically, wake inhibits phasic inhibition, whereas it promotes tonic inhibition compared to sleep. We further utilize a model of chemically induced inhibitory long-term potentiation (iLTP) to examine inhibitory plasticity. Intriguingly, while CA1 pyramidal neurons in both wake and sleep mice undergo iLTP, wake mice have a much higher magnitude. We also employ optogenetics and observe that inhibitory inputs from parvalbumin-, but not somatostatin-, expressing interneurons contribute to dynamic iLTP during sleep and wake. Finally, we demonstrate that synaptic insertion of α5-GABAA receptors underlies the wake-specific enhancement of iLTP at parvalbumin-synapses, which is independent of time of the day. These data reveal a previously unappreciated daily oscillation of inhibitory LTP in hippocampal neurons and uncover a dynamic contribution of inhibitory synapses in memory mechanisms across sleep and wake.
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22
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Zarrouki F, Goutal S, Vacca O, Garcia L, Tournier N, Goyenvalle A, Vaillend C. Abnormal Expression of Synaptic and Extrasynaptic GABAA Receptor Subunits in the Dystrophin-Deficient mdx Mouse. Int J Mol Sci 2022; 23:ijms232012617. [PMID: 36293496 PMCID: PMC9604073 DOI: 10.3390/ijms232012617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/21/2022] [Accepted: 10/11/2022] [Indexed: 11/17/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a neurodevelopmental disorder primarily caused by the loss of the full-length Dp427 dystrophin in both muscle and brain. The basis of the central comorbidities in DMD is unclear. Brain dystrophin plays a role in the clustering of central gamma-aminobutyric acid A receptors (GABAARs), and its loss in the mdx mouse alters the clustering of some synaptic subunits in central inhibitory synapses. However, the diversity of GABAergic alterations in this model is still fragmentary. In this study, the analysis of in vivo PET imaging of a benzodiazepine-binding site radioligand revealed that the global density of central GABAARs is unaffected in mdx compared with WT mice. In contrast, semi-quantitative immunoblots and immunofluorescence confocal imaging in tissue sections revealed complex and differential patterns of alterations of the expression levels and/or clustered distribution of a variety of synaptic and extrasynaptic GABAAR subunits in the hippocampus, cerebellum, cortex, and spinal cord. Hence, dystrophin loss not only affects the stabilization of synaptic GABAARs but also influences the subunit composition of GABAARs subtypes at both synaptic and extrasynaptic sites. This study provides new molecular outcome measures and new routes to evaluate the impact of treatments aimed at compensating alterations of the nervous system in DMD.
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Affiliation(s)
- Faouzi Zarrouki
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris Saclay, 91400 Saclay, France
- Université Paris-Saclay, UVSQ, Inserm, END-ICAP, 78000 Versailles, France
| | - Sébastien Goutal
- Université Paris-Saclay, INSERM, CNRS, CEA, Laboratoire d’Imagerie Biomédicale Multimodale (BioMaps), Service Hospitalier Frédéric Joliot, 91401 Orsay, France
| | - Ophélie Vacca
- Université Paris-Saclay, UVSQ, Inserm, END-ICAP, 78000 Versailles, France
| | - Luis Garcia
- Université Paris-Saclay, UVSQ, Inserm, END-ICAP, 78000 Versailles, France
| | - Nicolas Tournier
- Université Paris-Saclay, INSERM, CNRS, CEA, Laboratoire d’Imagerie Biomédicale Multimodale (BioMaps), Service Hospitalier Frédéric Joliot, 91401 Orsay, France
| | - Aurélie Goyenvalle
- Université Paris-Saclay, UVSQ, Inserm, END-ICAP, 78000 Versailles, France
| | - Cyrille Vaillend
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris Saclay, 91400 Saclay, France
- Correspondence:
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23
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Guzikowski NJ, Kavalali ET. Nano-organization of spontaneous GABAergic transmission directs its autonomous function in neuronal signaling. Cell Rep 2022; 40:111172. [PMID: 35947950 PMCID: PMC9392417 DOI: 10.1016/j.celrep.2022.111172] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 04/12/2022] [Accepted: 07/15/2022] [Indexed: 01/04/2023] Open
Abstract
Earlier studies delineated the precise arrangement of proteins that drive neurotransmitter release and postsynaptic signaling at excitatory synapses. However, spatial organization of neurotransmission at inhibitory synapses remains unclear. Here, we took advantage of the molecularly specific interaction of antimalarial artemisinins and the inhibitory synapse scaffold protein, gephyrin, to probe the functional organization of gamma-aminobutyric acid A receptor (GABAAR)-mediated neurotransmission in central synapses. Short-term application of artemisinins severely contracts the size and density of gephyrin and GABAaR γ2 subunit clusters. This size contraction elicits a neuronal activity-independent increase in Bdnf expression due to a specific reduction in GABAergic spontaneous, but not evoked, neurotransmission. The same functional effect could be mimicked by disruption of microtubules that link gephyrin to the neuronal cytoskeleton. These results suggest that the GABAergic postsynaptic apparatus possesses a concentric center-surround organization, where the periphery of gephyrin clusters selectively maintains spontaneous GABAergic neurotransmission facilitating its autonomous function regulating Bdnf expression.
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Affiliation(s)
- Natalie J. Guzikowski
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA
| | - Ege T. Kavalali
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA,Lead contact,Correspondence:
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24
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Distel JS, Flores RMO, Bienvenu A, Aguilera MO, Bonazzi M, Berón W. Ezrin and CD44 participate in the internalization process of
Coxiella burnetii
into non‐phagocytic cells. Biol Cell 2022; 114:237-253. [DOI: 10.1111/boc.202100096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 07/11/2022] [Accepted: 07/15/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Jesús S. Distel
- Instituto de Histología y Embriología Facultad de Ciencias Médicas Universidad Nacional de Cuyo ‐ CONICET Mendoza 5500 Argentina
| | - Rodolfo M. Ortiz Flores
- Instituto de Histología y Embriología Facultad de Ciencias Médicas Universidad Nacional de Cuyo ‐ CONICET Mendoza 5500 Argentina
- Cátedra de Microbiología Parasitología e Inmunología Facultad de Odontología Universidad Nacional de Cuyo Mendoza Argentina
| | - Arthur Bienvenu
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS Université de Montpellier Montpellier France
| | - Milton O. Aguilera
- Instituto de Histología y Embriología Facultad de Ciencias Médicas Universidad Nacional de Cuyo ‐ CONICET Mendoza 5500 Argentina
- Cátedra de Microbiología Parasitología e Inmunología Facultad de Odontología Universidad Nacional de Cuyo Mendoza Argentina
| | - Matteo Bonazzi
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS Université de Montpellier Montpellier France
| | - Walter Berón
- Instituto de Histología y Embriología Facultad de Ciencias Médicas Universidad Nacional de Cuyo ‐ CONICET Mendoza 5500 Argentina
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25
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Braga MFM, Juranek J, Eiden LE, Li Z, Figueiredo TH, de Araujo Furtado M, Marini AM. GABAergic circuits of the basolateral amygdala and generation of anxiety after traumatic brain injury. Amino Acids 2022; 54:1229-1249. [PMID: 35798984 DOI: 10.1007/s00726-022-03184-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/20/2022] [Indexed: 11/25/2022]
Abstract
Traumatic brain injury (TBI) has reached epidemic proportions around the world and is a major public health concern in the United States. Approximately 2.8 million individuals sustain a traumatic brain injury and are treated in an Emergency Department yearly in the U.S., and about 50,000 of them die. Persistent symptoms develop in 10-15% of the cases including neuropsychiatric disorders. Anxiety is the second most common neuropsychiatric disorder that develops in those with persistent neuropsychiatric symptoms after TBI. Abnormalities or atrophy in the temporal lobe has been shown in the overwhelming number of TBI cases. The basolateral amygdala (BLA), a temporal lobe structure that consolidates, stores and generates fear and anxiety-based behavioral outputs, is a critical brain region in the anxiety circuitry. In this review, we sought to capture studies that characterized the relationship between human post-traumatic anxiety and structural/functional alterations in the amygdala. We compared the human findings with results obtained with a reproducible mild TBI animal model that demonstrated a direct relationship between the alterations in the BLA and an anxiety-like phenotype. From this analysis, both preliminary insights, and gaps in knowledge, have emerged which may open new directions for the development of rational and more efficacious treatments.
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Affiliation(s)
- Maria F M Braga
- Department of Anatomy, Physiology and Genetics and Program in Neuroscience, Uniformed Services University of the Health Science School of Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Jenifer Juranek
- Department of Pediatric Surgery, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, TX, 77030, USA
| | - Lee E Eiden
- Section On Molecular Neuroscience, National Institute of Mental Health, Intramural Research Program, Bethesda, MD, 20814, USA
| | - Zheng Li
- Section On Synapse Development and Plasticity, National Institute of Mental Health, Intramural Research Program, Bethesda, MD, 20814, USA
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology and Genetics and Program in Neuroscience, Uniformed Services University of the Health Science School of Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Marcio de Araujo Furtado
- Department of Anatomy, Physiology and Genetics and Program in Neuroscience, Uniformed Services University of the Health Science School of Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Ann M Marini
- Department of Neurology and Program in Neuroscience, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
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26
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McCoy AM, Prevot TD, Mian MY, Cook JM, Frazer A, Sibille EL, Carreno FR, Lodge DJ. Positive Allosteric Modulation of α5-GABAA Receptors Reverses Stress-Induced Alterations in Dopamine System Function and Prepulse Inhibition of Startle. Int J Neuropsychopharmacol 2022; 25:688-698. [PMID: 35732272 PMCID: PMC9380714 DOI: 10.1093/ijnp/pyac035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/24/2022] [Accepted: 06/21/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Up to 64% of patients diagnosed with posttraumatic stress disorder (PTSD) experience psychosis, likely attributable to aberrant dopamine neuron activity. We have previously demonstrated that positive allosteric modulators of α5-GABAARs can selectively decrease hippocampal activity and reverse psychosis-like physiological and behavioral alterations in a rodent model used to study schizophrenia; however, whether this approach translates to a PTSD model remains to be elucidated. METHODS We utilized a 2-day inescapable foot shock (IS) procedure to induce stress-related pathophysiology in male Sprague-Dawley rats. We evaluated the effects of intra-ventral hippocampus (vHipp) administration GL-II-73, an α5-GABAAR, or viral overexpression of the α5 subunit, using in vivo electrophysiology and behavioral measures in control and IS-treated rats. RESULTS IS significantly increased ventral tegmental area dopamine neuron population activity, or the number of dopamine neurons firing spontaneously (n = 6; P = .016), consistent with observation in multiple rodent models used to study psychosis. IS also induced deficits in sensorimotor gating, as measured by reduced prepulse inhibition of startle (n = 12; P = .039). Interestingly, intra-vHipp administration of GL-II-73 completely reversed IS-induced increases in dopamine neuron population activity (n = 6; P = .024) and deficits in prepulse inhibition (n = 8; P = .025), whereas viral overexpression of the α5 subunit in the vHipp was not effective. CONCLUSIONS Our results demonstrate that pharmacological intervention augmenting α5-GABAAR function, but not α5 overexpression in itself, can reverse stress-induced deficits related to PTSD in a rodent model, providing a potential site of therapeutic intervention to treat comorbid psychosis in PTSD.
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Affiliation(s)
- Alexandra M McCoy
- Correspondence: Alexandra M. McCoy, BS, 7703 Floyd Curl Drive, MC 7764, San Antonio, TX, 78229, USA ()
| | - Thomas D Prevot
- Campbell Family Mental Health Research Institute of CAMH, Toronto, ON, Canada,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Md Yenus Mian
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - James M Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Alan Frazer
- Department of Pharmacology and Center for Biomedical Neuroscience, UT Health San Antonio, San Antonio, Texas, USA,South Texas Veterans Health Care System, Audie L. Murphy Division, San Antonio, Texas, USA
| | - Etienne L Sibille
- Campbell Family Mental Health Research Institute of CAMH, Toronto, ON, Canada,Department of Psychiatry, University of Toronto, Toronto, ON, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Flavia R Carreno
- Department of Pharmacology and Center for Biomedical Neuroscience, UT Health San Antonio, San Antonio, Texas, USA,South Texas Veterans Health Care System, Audie L. Murphy Division, San Antonio, Texas, USA
| | - Daniel J Lodge
- Department of Pharmacology and Center for Biomedical Neuroscience, UT Health San Antonio, San Antonio, Texas, USA,South Texas Veterans Health Care System, Audie L. Murphy Division, San Antonio, Texas, USA
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27
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Muhia M, YuanXiang P, Sedlacik J, Schwarz JR, Heisler FF, Gromova KV, Thies E, Breiden P, Pechmann Y, Kreutz MR, Kneussel M. Muskelin regulates actin-dependent synaptic changes and intrinsic brain activity relevant to behavioral and cognitive processes. Commun Biol 2022; 5:589. [PMID: 35705737 PMCID: PMC9200775 DOI: 10.1038/s42003-022-03446-1] [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: 11/25/2020] [Accepted: 05/04/2022] [Indexed: 12/02/2022] Open
Abstract
Muskelin (Mkln1) is implicated in neuronal function, regulating plasma membrane receptor trafficking. However, its influence on intrinsic brain activity and corresponding behavioral processes remains unclear. Here we show that murine Mkln1 knockout causes non-habituating locomotor activity, increased exploratory drive, and decreased locomotor response to amphetamine. Muskelin deficiency impairs social novelty detection while promoting the retention of spatial reference memory and fear extinction recall. This is strongly mirrored in either weaker or stronger resting-state functional connectivity between critical circuits mediating locomotor exploration and cognition. We show that Mkln1 deletion alters dendrite branching and spine structure, coinciding with enhanced AMPAR-mediated synaptic transmission but selective impairment in synaptic potentiation maintenance. We identify muskelin at excitatory synapses and highlight its role in regulating dendritic spine actin stability. Our findings point to aberrant spine actin modulation and changes in glutamatergic synaptic function as critical mechanisms that contribute to the neurobehavioral phenotype arising from Mkln1 ablation. A murine muskelin knockout induces increased exploratory drive and alters cognition and functional connectivity. These effects correlate with actin-dependent changes in dendritic branching, spine structure, and AMPAR-mediated synaptic transmission.
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Affiliation(s)
- Mary Muhia
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany. .,Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria.
| | - PingAn YuanXiang
- RG Neuroplasticity Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany
| | - Jan Sedlacik
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Biomedical Engineering Department, Centre for the Developing Brain, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Jürgen R Schwarz
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany
| | - Frank F Heisler
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany
| | - Kira V Gromova
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany
| | - Edda Thies
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany
| | - Petra Breiden
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany
| | - Yvonne Pechmann
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany
| | - Michael R Kreutz
- RG Neuroplasticity Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany.,Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Matthias Kneussel
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251, Hamburg, Germany.
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Kudryashova IV. Inhibitory Control of Short-Term Plasticity during Paired Pulse Stimulation Depends on Actin Polymerization. NEUROCHEM J+ 2022. [DOI: 10.1134/s1819712422020106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Chapman CA, Nuwer JL, Jacob TC. The Yin and Yang of GABAergic and Glutamatergic Synaptic Plasticity: Opposites in Balance by Crosstalking Mechanisms. Front Synaptic Neurosci 2022; 14:911020. [PMID: 35663370 PMCID: PMC9160301 DOI: 10.3389/fnsyn.2022.911020] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 04/26/2022] [Indexed: 01/12/2023] Open
Abstract
Synaptic plasticity is a critical process that regulates neuronal activity by allowing neurons to adjust their synaptic strength in response to changes in activity. Despite the high proximity of excitatory glutamatergic and inhibitory GABAergic postsynaptic zones and their functional integration within dendritic regions, concurrent plasticity has historically been underassessed. Growing evidence for pathological disruptions in the excitation and inhibition (E/I) balance in neurological and neurodevelopmental disorders indicates the need for an improved, more "holistic" understanding of synaptic interplay. There continues to be a long-standing focus on the persistent strengthening of excitation (excitatory long-term potentiation; eLTP) and its role in learning and memory, although the importance of inhibitory long-term potentiation (iLTP) and depression (iLTD) has become increasingly apparent. Emerging evidence further points to a dynamic dialogue between excitatory and inhibitory synapses, but much remains to be understood regarding the mechanisms and extent of this exchange. In this mini-review, we explore the role calcium signaling and synaptic crosstalk play in regulating postsynaptic plasticity and neuronal excitability. We examine current knowledge on GABAergic and glutamatergic synapse responses to perturbances in activity, with a focus on postsynaptic plasticity induced by short-term pharmacological treatments which act to either enhance or reduce neuronal excitability via ionotropic receptor regulation in neuronal culture. To delve deeper into potential mechanisms of synaptic crosstalk, we discuss the influence of synaptic activity on key regulatory proteins, including kinases, phosphatases, and synaptic structural/scaffolding proteins. Finally, we briefly suggest avenues for future research to better understand the crosstalk between glutamatergic and GABAergic synapses.
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Affiliation(s)
| | | | - Tija C. Jacob
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
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Kramer RH, Rajappa R. Interrogating the function of GABA A receptors in the brain with optogenetic pharmacology. Curr Opin Pharmacol 2022; 63:102198. [PMID: 35276498 DOI: 10.1016/j.coph.2022.102198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/21/2022] [Accepted: 01/25/2022] [Indexed: 11/26/2022]
Abstract
To better understand neural circuits and behavior, microbial opsins have been developed as optogenetic tools for stimulating or inhibiting action potentials with high temporal and spatial precision. However, if we seek a more reductionist understanding of how neuronal circuits operate, we also need high-resolution tools for perturbing the function of synapses. By combining photochemical tools and molecular biology, a wide variety of light-regulated neurotransmitter receptors have been developed, enabling photo-control of excitatory, inhibitory, and modulatory synaptic transmission. Here we focus on photo-control of GABAA receptors, ligand-gated Cl- channels that underlie almost all synaptic inhibition in the mammalian brain. By conjugating a photoswitchable tethered ligand onto a genetically-modified subunit of the GABAA receptor, light-sensitivity can be conferred onto specific isoforms of the receptor. Through gene editing, this attachment site can be knocked into the genome, enabling photocontrol of endogenous GABAA receptors. This strategy can be employed to explore the cell biology and neurophysiology of GABAA receptors. This includes investigating how specific isoforms contribute to synaptic and tonic inhibition and understanding the roles they play in brain development, long-term synaptic plasticity, and learning and memory.
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Affiliation(s)
- Richard H Kramer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, United States; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States.
| | - Rajit Rajappa
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, United States; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States
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31
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Belelli D, Phillips GD, Atack JR, Lambert JJ. Relating neurosteroid modulation of inhibitory neurotransmission to behaviour. J Neuroendocrinol 2022; 34:e13045. [PMID: 34644812 DOI: 10.1111/jne.13045] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/24/2021] [Accepted: 09/15/2021] [Indexed: 12/11/2022]
Abstract
Studies in the 1980s revealed endogenous metabolites of progesterone and deoxycorticosterone to be potent, efficacious, positive allosteric modulators (PAMs) of the GABAA receptor (GABAA R). The discovery that such steroids are locally synthesised in the central nervous system (CNS) promoted the thesis that neural inhibition in the CNS may be "fine-tuned" by these neurosteroids to influence behaviour. In preclinical studies, these neurosteroids exhibited anxiolytic, anticonvulsant, analgesic and sedative properties and, at relatively high doses, induced a state of general anaesthesia, a profile consistent with their interaction with GABAA Rs. However, realising the therapeutic potential of either endogenous neurosteroids or synthetic "neuroactive" steroids has proven challenging. Recent approval by the Food and Drug Administration of the use of allopregnanolone (brexanolone) to treat postpartum depression has rekindled enthusiasm for exploring their potential as new medicines. Although neurosteroids are selective for GABAA Rs, they exhibit little or no selectivity across the many GABAA R subtypes. Nevertheless, a relatively minor population of receptors incorporating the δ-subunit (δ-GABAA Rs) appears to be an important contributor to their behavioural effects. Here, we consider how neurosteroids acting upon GABAA Rs influence neuronal signalling, as well as how such effects may acutely and persistently influence behaviour, and explore the case for developing selective PAMs of δ-GABAA R subtypes for the treatment of psychiatric disorders.
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Affiliation(s)
- Delia Belelli
- Neuroscience, Division of Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Grant D Phillips
- Neuroscience, Division of Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - John R Atack
- Medicines Discovery Institute, Cardiff University, Cardiff, UK
| | - Jeremy J Lambert
- Neuroscience, Division of Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
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32
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Cai WT, Kim WY, Kwak MJ, Rim H, Lee SE, Riecken LB, Morrison H, Kim J. Disruption of amphetamine sensitization by alteration of dendritic thin spines in the nucleus accumbens core. J Neurochem 2022; 161:266-280. [DOI: 10.1111/jnc.15582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/17/2022] [Accepted: 01/20/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Wen Ting Cai
- Department of Physiology Yonsei University College of Medicine Seoul Republic of Korea
| | - Wha Young Kim
- Department of Physiology Yonsei University College of Medicine Seoul Republic of Korea
| | - Myung Ji Kwak
- Department of Medical Sciences Yonsei University College of Medicine Seoul Republic of Korea
| | - Haeun Rim
- Department of Medical Sciences Yonsei University College of Medicine Seoul Republic of Korea
| | - Seung Eun Lee
- Virus Facility, Research Animal Source Center Korea Institute of Science and Technology Seoul Republic of Korea
| | | | - Helen Morrison
- Leibniz Institute on Aging Fritz Lipmann Institute Jena Germany
| | - Jeong‐Hoon Kim
- Department of Physiology Yonsei University College of Medicine Seoul Republic of Korea
- Department of Medical Sciences Yonsei University College of Medicine Seoul Republic of Korea
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Perez SM, McCoy AM, Prevot TD, Mian MY, Carreno FR, Frazer A, Cook JM, Sibille E, Lodge DJ. Hippocampal α5-GABA A Receptors Modulate Dopamine Neuron Activity in the Rat Ventral Tegmental Area. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2022; 3:78-86. [PMID: 36712569 PMCID: PMC9874136 DOI: 10.1016/j.bpsgos.2021.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 11/22/2021] [Accepted: 12/16/2021] [Indexed: 02/01/2023] Open
Abstract
Background Aberrant dopamine neuron activity is attributable to hyperactivity in hippocampal subfields driving a pathological increase in dopamine neuron activity, which is positively correlated with psychosis in humans. Evidence indicates that hippocampal hyperactivity is due to loss of intrinsic GABAergic (gamma-aminobutyric acidergic) inhibition. We have previously demonstrated that hippocampal GABAergic neurotransmission can be modulated by targeting α5-GABAA receptors, which are preferentially expressed in hippocampal regions. Positive and negative allosteric modulators of α5-GABAA receptors (α5-PAMs and α5-NAMs) elicit effects on hippocampal-dependent behaviors. We posited that the selective manipulation of hippocampal inhibition, using α5-PAMs or α5-NAMs, would modulate dopamine activity in control rats. Further, α5-PAMs would reverse aberrant dopamine neuron activity in a rodent model with schizophrenia-related pathophysiologies (methylazoxymethanol acetate [MAM] model). Methods We performed in vivo extracellular recordings of ventral tegmental area dopamine neurons in anesthetized rats to compare the effects of two novel, selective α5-PAMs (GL-II-73, MP-III-022), a nonselective α-PAM (midazolam), and two selective α5-NAMs (L-655,708, TB 21007) in control and MAM-treated male Sprague Dawley rats (n = 5-9). Results Systemic or intracranial administration of selective α5-GABAA receptor modulators regulated dopamine activity. Specifically, both α5-NAMs increased dopamine neuron activity in control rats, whereas GL-II-73, MP-III-022, and L-655,708 attenuated aberrant dopamine neuron activity in MAM-treated rats, an effect mediated by the ventral hippocampus. Conclusions This study demonstrated that α5-GABAA receptor modulation can regulate dopamine neuron activity under control or abnormal activity, providing additional evidence that α5-PAMs and α5-NAMs may have therapeutic applications in psychosis and other psychiatric diseases where aberrant hippocampal activity is present.
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Affiliation(s)
- Stephanie M. Perez
- Department of Pharmacology and Center for Biomedical Neuroscience, UT Health San Antonio, San Antonio, Texas,Audie L. Murphy Memorial Veterans Hospital, South Texas Veterans Health Care System, San Antonio, Texas,Address correspondence to Stephanie M. Perez, Ph.D.
| | - Alexandra M. McCoy
- Department of Pharmacology and Center for Biomedical Neuroscience, UT Health San Antonio, San Antonio, Texas,Audie L. Murphy Memorial Veterans Hospital, South Texas Veterans Health Care System, San Antonio, Texas
| | - Thomas D. Prevot
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Md Yeunus Mian
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin
| | - Flavia R. Carreno
- Department of Pharmacology and Center for Biomedical Neuroscience, UT Health San Antonio, San Antonio, Texas
| | - Alan Frazer
- Department of Pharmacology and Center for Biomedical Neuroscience, UT Health San Antonio, San Antonio, Texas,Audie L. Murphy Memorial Veterans Hospital, South Texas Veterans Health Care System, San Antonio, Texas
| | - James M. Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin
| | - Etienne Sibille
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Daniel J. Lodge
- Department of Pharmacology and Center for Biomedical Neuroscience, UT Health San Antonio, San Antonio, Texas,Audie L. Murphy Memorial Veterans Hospital, South Texas Veterans Health Care System, San Antonio, Texas
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Al Awabdh S, Donneger F, Goutierre M, Séveno M, Vigy O, Weinzettl P, Russeau M, Moutkine I, Lévi S, Marin P, Poncer JC. Gephyrin Interacts with the K-Cl Cotransporter KCC2 to Regulate Its Surface Expression and Function in Cortical Neurons. J Neurosci 2022; 42:166-182. [PMID: 34810232 PMCID: PMC8802937 DOI: 10.1523/jneurosci.2926-20.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 08/31/2021] [Accepted: 10/17/2021] [Indexed: 11/21/2022] Open
Abstract
The K+-Cl- cotransporter KCC2, encoded by the Slc12a5 gene, is a neuron-specific chloride extruder that tunes the strength and polarity of GABAA receptor-mediated transmission. In addition to its canonical ion transport function, KCC2 also regulates spinogenesis and excitatory synaptic function through interaction with a variety of molecular partners. KCC2 is enriched in the vicinity of both glutamatergic and GABAergic synapses, the activity of which in turn regulates its membrane stability and function. KCC2 interaction with the submembrane actin cytoskeleton via 4.1N is known to control its anchoring near glutamatergic synapses on dendritic spines. However, the molecular determinants of KCC2 clustering near GABAergic synapses remain unknown. Here, we used proteomics to identify novel KCC2 interacting proteins in the adult rat neocortex. We identified both known and novel candidate KCC2 partners, including some involved in neuronal development and synaptic transmission. These include gephyrin, the main scaffolding molecule at GABAergic synapses. Gephyrin interaction with endogenous KCC2 was confirmed by immunoprecipitation from rat neocortical extracts. We showed that gephyrin stabilizes plasmalemmal KCC2 and promotes its clustering in hippocampal neurons, mostly but not exclusively near GABAergic synapses, thereby controlling KCC2-mediated chloride extrusion. This study identifies gephyrin as a novel KCC2 anchoring molecule that regulates its membrane expression and function in cortical neurons.SIGNIFICANCE STATEMENT Fast synaptic inhibition in the brain is mediated by chloride-permeable GABAA receptors (GABAARs) and therefore relies on transmembrane chloride gradients. In neurons, these gradients are primarily maintained by the K/Cl cotransporter KCC2. Therefore, understanding the mechanisms controlling KCC2 expression and function is crucial to understand its physiological regulation and rescue its function in the pathology. KCC2 function depends on its membrane expression and clustering, but the underlying mechanisms remain unknown. We describe the interaction between KCC2 and gephyrin, the main scaffolding protein at inhibitory synapses. We show that gephyrin controls plasmalemmal KCC2 clustering and that loss of gephyrin compromises KCC2 function. Our data suggest functional units comprising GABAARs, gephyrin, and KCC2 act to regulate synaptic GABA signaling.
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Affiliation(s)
- Sana Al Awabdh
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Florian Donneger
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Marie Goutierre
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Martial Séveno
- BCM, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Oana Vigy
- IGF, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Pauline Weinzettl
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
- Institute of Biotechnology, University of Applied Sciences, Krems, Austria
| | - Marion Russeau
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Imane Moutkine
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Sabine Lévi
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Philippe Marin
- IGF, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Jean Christophe Poncer
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
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Hu Y, Liu F, Peng W, Song S, Zhang C, Meng X. Overexpression of miR-99a in hippocampus leads to impairment of reversal learning in mice. Behav Brain Res 2022; 416:113542. [PMID: 34425183 DOI: 10.1016/j.bbr.2021.113542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 08/05/2021] [Accepted: 08/19/2021] [Indexed: 11/28/2022]
Abstract
As one of the most common human genetic disorders, Down syndrome (DS) is characterized by a mild-to-moderate cognitive disability, which mainly results from genes overexpression on chromosome 21. The expression of miR-99a, a gene harboring on chromosome 21, is increased by 50 folds in DS brain samples. This study aims to investigate the effect of miR-99a overexpression in the hippocampus on mouse behaviors and explore the underlying mechanisms. Lentivirus vectors were delivered into the hippocampus for focal miR-99a overexpression in mice. Then behaviors were observed by an open field, elevated plus maze, rotarod motor test, and Morris water maze. The genes affected by miR-99a were identified by RNA sequencing (RNA-seq) and confirmed by quantitative RT-PCR (qRT-PCR) in samples isolated from the hippocampus injected with lentivirus-GFP-miR-99a or lentivirus-GFP vectors. It was found that the expression of miR-99a with intrahippocampal delivery of lentivirus-GFP-miR-99a resulted in reversal learning impairment in mice although it had no influence on motor function and anxiety. Meanwhile, RNA-seq results showed that 92 genes including mRNAs and microRNAs were significantly regulated by miR-99a, consistent with qRT-PCR consequence. Moreover, dual-luciferase reporter assay showed that miR-99a could directly bind to the 3'-untranslated regions (3'UTR) of target genes (Clic6 and Kcnj13) with an inhibitory effect on their activity. Furthermore, we also found that miR-99a overexpression affected different biological processes by bioinformatic analyses. Our study showed that miR-99a overexpression in the hippocampus leads to cognitive impairment through regulating the expressions of various genes, which reveals a novel function of miR-99a and provides new insights into understanding the pathophysiologic process of DS.
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Affiliation(s)
- Yue Hu
- Department of Neurobiology, Institute of Brain Research, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Feng Liu
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Wenpeng Peng
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Shuxin Song
- Department of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, 250022, China
| | - Chun Zhang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Xianfang Meng
- Department of Neurobiology, Institute of Brain Research, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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Non-linear GABA A receptors promote synaptic inhibition in developing neurons : Commentary on Lodge et al. (2021) Sparsification of AP firing in adult-born hippocampal granule cells via voltage-dependent α5-GABA A receptors. Cell Rep 37:109768. Pflugers Arch 2021; 474:181-183. [PMID: 34907453 PMCID: PMC8766374 DOI: 10.1007/s00424-021-02652-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 11/25/2022]
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Abstract
In 1959, E. G. Gray described two different types of synapses in the brain for the first time: symmetric and asymmetric. Later on, symmetric synapses were associated with inhibitory terminals, and asymmetric synapses to excitatory signaling. The balance between these two systems is critical to maintain a correct brain function. Likewise, the modulation of both types of synapses is also important to maintain a healthy equilibrium. Cerebral circuitry responds differently depending on the type of damage and the timeline of the injury. For example, promoting symmetric signaling following ischemic damage is beneficial only during the acute phase; afterwards, it further increases the initial damage. Synapses can be also altered by players not directly related to them; the chronic and long-term neurodegeneration mediated by tau proteins primarily targets asymmetric synapses by decreasing neuronal plasticity and functionality. Dopamine represents the main modulating system within the central nervous system. Indeed, the death of midbrain dopaminergic neurons impairs locomotion, underlying the devastating Parkinson’s disease. Herein, we will review studies on symmetric and asymmetric synapses plasticity after three different stressors: symmetric signaling under acute damage—ischemic stroke; asymmetric signaling under chronic and long-term neurodegeneration—Alzheimer’s disease; symmetric and asymmetric synapses without modulation—Parkinson’s disease.
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Yuan C, Gao A, Xu Q, Zhang B, Xue R, Dou Y, Yu C. A multi-dosing regimen to enhance the spatial memory of normal rats with α5-containing GABA A receptor negative allosteric modulator L-655,708. Psychopharmacology (Berl) 2021; 238:3375-3389. [PMID: 34389882 DOI: 10.1007/s00213-021-05951-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 08/03/2021] [Indexed: 01/20/2023]
Abstract
RATIONALE AND OBJECTIVES The reported inconsistent effects of negative allosteric modulators of α5-containing GABAA receptors on learning and memory may be attributed to receptor selectivity, effective plasma concentration maintenance, and administration time. This study aimed to compare the effects of L-655,708 administered by single-dosing regimen versus multi-dosing regimen on spatial memory, signaling molecules, and brain functional connectivity. METHODS After comparing the maintenance time of the effective plasma concentration of L-655,708 between multi-dosing and single-dosing regimens, we further compared the effects of the administration of the two regimens at different phases (before-learning, during-learning, and before-probe) of the Morris water maze (MWM) test on the performance of learning and memory and the levels of signaling molecules related to learning and memory in hippocampal tissues. Functional connectivity analyses between hippocampal and cortical regions were performed to further clarify the effects of the multi-dosing regimen. RESULTS The multi-dosing regimen could maintain the effective plasma concentration of L-655,708 much longer than the single-dosing regimen. Only the multi-dosing regimen for L-655,708 administration during the learning period led to significant improvement in spatial memory in the MWM test and increases in levels of glutamate receptors and phosphorylated signaling molecules (p-PKAα, p-CaMKII, and p-CREB-1). Compared with the vehicle control, the multi-dosing regimen increased the functional connectivity of the left hippocampal CA1 with cingulate and motor cortices. CONCLUSIONS A multi-dosing regimen for L-655,708 administered during the learning period is an effective strategy to improve spatial memory, increase signaling molecule levels, and enhance the functional connectivity of the hippocampus.
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Affiliation(s)
- Congcong Yuan
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China
| | - An Gao
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China
| | - Qiang Xu
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China
| | - Beibei Zhang
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China
| | - Rui Xue
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China
| | - Yan Dou
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China.
| | - Chunshui Yu
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, 300052, People's Republic of China.
- School of Medical Imaging, Tianjin Medical University, Tianjin, 300052, People's Republic of China.
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Wu K, Castellano D, Tian Q, Lu W. Distinct regulation of tonic GABAergic inhibition by NMDA receptor subtypes. Cell Rep 2021; 37:109960. [PMID: 34758303 PMCID: PMC8630577 DOI: 10.1016/j.celrep.2021.109960] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 09/03/2021] [Accepted: 10/15/2021] [Indexed: 11/17/2022] Open
Abstract
Tonic inhibition mediated by extrasynaptic GABAARs regulates various brain functions. However, the mechanisms that regulate tonic inhibition remain largely unclear. Here, we report distinct actions of GluN2A- and GluN2B-NMDA receptors (NMDARs) on tonic inhibition in hippocampal neurons under basal and high activity conditions. Specifically, overexpression of GluN2B, but not GluN2A, reduces α5-GABAAR surface expression and tonic currents. Additionally, knockout of GluN2A and GluN2B decreases and increases tonic currents, respectively. Mechanistically, GluN2A-NMDARs inhibit and GluN2B-NMDARs promote α5-GABAAR internalization, resulting in increased and decreased surface α5-GABAAR expression, respectively. Furthermore, GluN2A-NMDARs, but not GluN2B-NMDARs, are required for homeostatic potentiation of tonic inhibition induced by prolonged increase of neuronal activity. Last, tonic inhibition decreases during acute seizures, whereas it increases 24 h later, involving GluN2-NMDAR-dependent signaling. Collectively, these data reveal an NMDAR subunit-specific regulation of tonic inhibition in physiological and pathological conditions and provide mechanistic insight into activity-dependent modulation of tonic inhibition.
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Affiliation(s)
- Kunwei Wu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - David Castellano
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Qingjun Tian
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wei Lu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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Sparsification of AP firing in adult-born hippocampal granule cells via voltage-dependent α5-GABA A receptors. Cell Rep 2021; 37:109768. [PMID: 34610304 DOI: 10.1016/j.celrep.2021.109768] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/07/2021] [Accepted: 09/08/2021] [Indexed: 11/21/2022] Open
Abstract
GABA can depolarize immature neurons close to the action potential (AP) threshold in development and adult neurogenesis. Nevertheless, GABAergic synapses effectively inhibit AP firing in newborn granule cells of the adult hippocampus as early as two weeks post-mitosis. The underlying mechanisms are largely unclear. Here, we analyze GABAergic inputs in newborn hippocampal granule cells mediated by soma-targeting parvalbumin and dendrite-targeting somatostatin interneurons. Surprisingly, both interneuron subtypes activate α5-subunit-containing GABAA receptors (α5-GABAARs) in young neurons, showing a nonlinear voltage dependence with increasing conductance around the AP threshold. By contrast, in mature cells, parvalbumin interneurons mediate linear GABAergic synaptic currents lacking α5-subunits, while somatostatin interneurons continue to target nonlinear α5-GABAARs. Computational modeling shows that the voltage-dependent amplification of α5-GABAAR opening in young neurons is crucial for inhibition of AP firing to generate balanced and sparse firing activity, even with depolarized GABA reversal potential.
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Figueroa AG, Benkwitz C, Surges G, Kunz N, Homanics GE, Pearce RA. Hippocampal β2-GABA A receptors mediate LTP suppression by etomidate and contribute to long-lasting feedback but not feedforward inhibition of pyramidal neurons. J Neurophysiol 2021; 126:1090-1100. [PMID: 34406874 PMCID: PMC8560413 DOI: 10.1152/jn.00303.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The general anesthetic etomidate, which acts through γ-aminobutyric acid type A (GABAA) receptors, impairs the formation of new memories under anesthesia. This study addresses the molecular and cellular mechanisms by which this occurs. Here, using a new line of genetically engineered mice carrying the GABAA receptor (GABAAR) β2-N265M mutation, we tested the roles of receptors that incorporate GABAA receptor β2 versus β3 subunits to suppression of long-term potentiation (LTP), a cellular model of learning and memory. We found that brain slices from β2-N265M mice resisted etomidate suppression of LTP, indicating that the β2-GABAARs are an essential target in this model. As these receptors are most heavily expressed by interneurons in the hippocampus, this finding supports a role for interneuron modulation in etomidate control of synaptic plasticity. Nevertheless, β2 subunits are also expressed by pyramidal neurons, so they might also contribute. Therefore, using a previously established line of β3-N265M mice, we also examined the contributions of β2- versus β3-GABAARs to GABAA,slow dendritic inhibition, because dendritic inhibition is particularly well suited to controlling synaptic plasticity. We also examined their roles in long-lasting suppression of population activity through feedforward and feedback inhibition. We found that both β2- and β3-GABAARs contribute to GABAA,slow inhibition and that both β2- and β3-GABAARs contribute to feedback inhibition, whereas only β3-GABAARs contribute to feedforward inhibition. We conclude that modulation of β2-GABAARs is essential to etomidate suppression of LTP. Furthermore, to the extent that this occurs through GABAARs on pyramidal neurons, it is through modulation of feedback inhibition.NEW & NOTEWORTHY Etomidate exerts its anesthetic actions through GABAA receptors. However, the mechanism remains unknown. Here, using a hippocampal brain slice model, we show that β2-GABAARs are essential to this effect. We also show that these receptors contribute to long-lasting dendritic inhibition in feedback but not feedforward inhibition of pyramidal neurons. These findings hold implications for understanding how anesthetics block memory formation and, more generally, how inhibitory circuits control learning and memory.
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Affiliation(s)
- Alexander G Figueroa
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Claudia Benkwitz
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin.,Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Gabe Surges
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Nicholas Kunz
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Gregg E Homanics
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Robert A Pearce
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin
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Extracellular Metalloproteinases in the Plasticity of Excitatory and Inhibitory Synapses. Cells 2021; 10:cells10082055. [PMID: 34440823 PMCID: PMC8391609 DOI: 10.3390/cells10082055] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/03/2021] [Accepted: 08/05/2021] [Indexed: 02/07/2023] Open
Abstract
Long-term synaptic plasticity is shaped by the controlled reorganization of the synaptic proteome. A key component of this process is local proteolysis performed by the family of extracellular matrix metalloproteinases (MMPs). In recent years, considerable progress was achieved in identifying extracellular proteases involved in neuroplasticity phenomena and their protein substrates. Perisynaptic metalloproteinases regulate plastic changes at synapses through the processing of extracellular and membrane proteins. MMP9 was found to play a crucial role in excitatory synapses by controlling the NMDA-dependent LTP component. In addition, MMP3 regulates the L-type calcium channel-dependent form of LTP as well as the plasticity of neuronal excitability. Both MMP9 and MMP3 were implicated in memory and learning. Moreover, altered expression or mutations of different MMPs are associated with learning deficits and psychiatric disorders, including schizophrenia, addiction, or stress response. Contrary to excitatory drive, the investigation into the role of extracellular proteolysis in inhibitory synapses is only just beginning. Herein, we review the principal mechanisms of MMP involvement in the plasticity of excitatory transmission and the recently discovered role of proteolysis in inhibitory synapses. We discuss how different matrix metalloproteinases shape dynamics and turnover of synaptic adhesome and signal transduction pathways in neurons. Finally, we discuss future challenges in exploring synapse- and plasticity-specific functions of different metalloproteinases.
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Anesthesiology: Resetting Our Sights on Long-term Outcomes: The 2020 John W. Severinghaus Lecture on Translational Science. Anesthesiology 2021; 135:18-30. [PMID: 33901279 DOI: 10.1097/aln.0000000000003798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Anesthesiologists have worked relentlessly to improve intraoperative anesthesia care. They are now well positioned to expand their horizons and address many of the longer-term adverse consequences of anesthesia and surgery. Perioperative neurocognitive disorders, chronic postoperative pain, and opioid misuse are not inevitable adverse outcomes; rather, they are preventable and treatable conditions that deserve attention. The author's research team has investigated why patients experience new cognitive deficits after anesthesia and surgery. Their animal studies have shown that anesthetic drugs trigger overactivity of "memory-blocking receptors" that persists after the drugs are eliminated, and they have discovered new strategies to preserve brain function by repurposing available drugs and developing novel therapeutics that inhibit these receptors. Clinical trials are in progress to examine the cognitive outcomes of such strategies. This work is just one example of how anesthesiologists are advancing science with the goal of improving the lives of patients.
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Nuwer JL, Brady ML, Povysheva NV, Coyne A, Jacob TC. Sustained treatment with an α5 GABA A receptor negative allosteric modulator delays excitatory circuit development while maintaining GABAergic neurotransmission. Neuropharmacology 2021; 197:108724. [PMID: 34284042 DOI: 10.1016/j.neuropharm.2021.108724] [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: 04/01/2021] [Revised: 07/01/2021] [Accepted: 07/14/2021] [Indexed: 01/02/2023]
Abstract
α5 subunit GABA type A receptor (GABAAR) preferring negative allosteric modulators (NAMs) are cognitive enhancers with antidepressant-like effects. α5-NAM success in treating mouse models of neurodevelopmental disorders with excessive inhibition have led to Phase 2 clinical trials for Down syndrome. Despite in vivo efficacy, no study has examined the effects of continued α5-NAM treatment on inhibitory and excitatory synapse plasticity to identify mechanisms of action. Here we used L-655,708, an imidazobenzodiazepine that acts as a highly selective but weak α5-NAM, to investigate the impact of sustained treatment on hippocampal neuron synapse and dendrite development. We show that 2-day pharmacological reduction of α5-GABAAR signaling from DIV12-14, when GABAARs contribute to depolarization, delays dendritic spine maturation and the NMDA receptor (NMDAR) GluN2B/GluN2A developmental shift. In contrast, α5-NAM treatment from DIV19-21, when hyperpolarizing GABAAR signaling predominates, enhances surface synaptic GluN2A while decreasing GluN2B. Despite changes in NMDAR subtype surface levels and localization, total levels of key excitatory synapse proteins were largely unchanged, and mEPSCs were unaltered. Importantly, 2-day α5-NAM treatment does not alter the total surface levels or distribution of α5-GABAARs, reduce the gephyrin inhibitory synaptic scaffold, or impair phasic or tonic inhibition. Furthermore, α5-NAM inhibition of the GABAAR tonic current in mature neurons is maintained after 2-day α5-NAM treatment, suggesting reduced tolerance liability, in contrast to other clinically relevant GABAAR-targeting drugs such as benzodiazepines. Together, these results show that α5-GABAARs contribute to dendritic spine maturation and excitatory synapse development via a NMDAR dependent mechanism without perturbing overall neuronal excitability.
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Affiliation(s)
- Jessica L Nuwer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Megan L Brady
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nadya V Povysheva
- Department of Neuroscience and Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Amanda Coyne
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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Wyroślak M, Lebida K, Mozrzymas JW. Induction of Inhibitory Synaptic Plasticity Enhances Tonic Current by Increasing the Content of α5-Subunit Containing GABA A Receptors in Hippocampal Pyramidal Neurons. Neuroscience 2021; 467:39-46. [PMID: 34033868 DOI: 10.1016/j.neuroscience.2021.05.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 11/16/2022]
Abstract
It is known that besides synaptic inhibition, there is a persistent component of inhibitory drive mediated by tonic currents which is believed to mediate majority of the total inhibitory charge in hippocampal neurons. Tonic currents, depending on cell types, can be mediated by a variety of GABAA receptor (GABAAR) subtypes but in pyramidal neurons, α5-subunit containing receptors were found to be predominant. Importantly, α5-GABAARs were implicated in both inhibitory and excitatory synaptic plasticity as well as in a variety of cognitive tasks. In the present study, we asked whether the protocol that evokes NMDAR-dependent GABAergic inhibitory long-term potentiation (iLTP) also induces the plasticity of tonic inhibition in hippocampal pyramidal neurons. Our whole-cell patch-clamp recordings revealed that the induction of this type of iLTP is associated with a marked increase in tonic current. By using the specific inverse agonist of α5-containing GABAARs (L-655,709) we provide evidence that this plastic change in tonic current is correlated with an increased proportion of this type of GABAARs. On the contrary, the iLTP induction did not affect the tonic current potentiated by THIP, indicating that the pool of δ subunit-containing GABAARs receptors remains unaffected. We conclude that the α5-GABAARs-dependent plasticity of tonic inhibition is a novel dimension of the neuroplasticity of the inhibitory drive in the hippocampal principal neurons. Overall, α5-containing GABAARs emerge as key players in a variety of plasticity mechanisms operating over a large span of time and spatial scales.
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Affiliation(s)
- Marcin Wyroślak
- Department of Biophysics and Neuroscience, Wroclaw Medical University, 50-367 Wroclaw, Poland.
| | - Katarzyna Lebida
- Department of Biophysics and Neuroscience, Wroclaw Medical University, 50-367 Wroclaw, Poland
| | - Jerzy W Mozrzymas
- Department of Biophysics and Neuroscience, Wroclaw Medical University, 50-367 Wroclaw, Poland
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Maingret F, Groc L. Characterization of the Functional Cross-Talk between Surface GABA A and Dopamine D5 Receptors. Int J Mol Sci 2021; 22:ijms22094867. [PMID: 34064454 PMCID: PMC8125140 DOI: 10.3390/ijms22094867] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/27/2021] [Accepted: 04/30/2021] [Indexed: 01/17/2023] Open
Abstract
The γ-aminobutyric acid type A receptor (GABAAR) plays a major role in fast inhibitory synaptic transmission and is highly regulated by the neuromodulator dopamine. In this aspect, most of the attention has been focused on the classical intracellular signaling cascades following dopamine G-protein-coupled receptor activation. Interestingly, the GABAAR and dopamine D5 receptor (D5R) have been shown to physically interact in the hippocampus, but whether a functional cross-talk occurs is still debated. In the present study, we use a combination of imaging and single nanoparticle tracking in live hippocampal neurons to provide evidence that GABAARs and D5Rs form dynamic surface clusters. Disrupting the GABAAR–D5R interaction with a competing peptide leads to an increase in the diffusion coefficient and the explored area of both receptors, and a drop in immobile synaptic GABAARs. By means of patch-clamp recordings, we show that this fast lateral redistribution of surface GABAARs correlates with a robust depression in the evoked GABAergic currents. Strikingly, it also shifts in time the expression of long-term potentiation at glutamatergic synapses. Together, our data both set the plasma membrane as the primary stage of a functional interplay between GABAAR and D5R, and uncover a non-canonical role in regulating synaptic transmission.
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Affiliation(s)
- François Maingret
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, UMR 5297, 33076 Bordeaux, France;
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, 33076 Bordeaux, France
- Correspondence:
| | - Laurent Groc
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, UMR 5297, 33076 Bordeaux, France;
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, 33076 Bordeaux, France
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47
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Astrocytic IGF-IRs Induce Adenosine-Mediated Inhibitory Downregulation and Improve Sensory Discrimination. J Neurosci 2021; 41:4768-4781. [PMID: 33911021 DOI: 10.1523/jneurosci.0005-21.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/20/2021] [Accepted: 03/28/2021] [Indexed: 12/13/2022] Open
Abstract
Insulin-like growth factor-I (IGF-I) signaling plays a key role in learning and memory processes. While the effects of IGF-I on neurons have been studied extensively, the involvement of astrocytes in IGF-I signaling and the consequences on synaptic plasticity and animal behavior remain unknown. We have found that IGF-I induces long-term potentiation (LTPIGFI) of the postsynaptic potentials that is caused by a long-term depression of inhibitory synaptic transmission in mice. We have demonstrated that this long-lasting decrease in the inhibitory synaptic transmission is evoked by astrocytic activation through its IGF-I receptors (IGF-IRs). We show that LTPIGFI not only increases the output of pyramidal neurons, but also favors the NMDAR-dependent LTP, resulting in the crucial information processing at the barrel cortex since specific deletion of IGF-IR in cortical astrocytes impairs the whisker discrimination task. Our work reveals a novel mechanism and functional consequences of IGF-I signaling on cortical inhibitory synaptic plasticity and animal behavior, revealing that astrocytes are key elements in these processes.SIGNIFICANCE STATEMENT Insulin-like growth factor-I (IGF-I) signaling plays key regulatory roles in multiple processes of brain physiology, such as learning and memory. Yet, the underlying mechanisms remain largely undefined. Here we demonstrate that astrocytes respond to IGF-I signaling, elevating their intracellular Ca2+ and stimulating the release of ATP/adenosine, which triggers the LTD of cortical inhibitory synapses, thus regulating the behavioral task performance related to cortical sensory information processing. Therefore, the present work represents a major conceptual advance in our knowledge of the cellular basis of IGF-I signaling in brain function, by including for the first time astrocytes as key mediators of IGF-I actions on synaptic plasticity, cortical sensory information discrimination and animal behavior.
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48
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Wu K, Han W, Tian Q, Li Y, Lu W. Activity- and sleep-dependent regulation of tonic inhibition by Shisa7. Cell Rep 2021; 34:108899. [PMID: 33761345 PMCID: PMC8025742 DOI: 10.1016/j.celrep.2021.108899] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 12/22/2020] [Accepted: 03/03/2021] [Indexed: 02/08/2023] Open
Abstract
Tonic inhibition mediated by extrasynaptic γ-aminobutyric acid type A receptors (GABAARs) critically regulates neuronal excitability and brain function. However, the mechanisms regulating tonic inhibition remain poorly understood. Here, we report that Shisa7 is critical for tonic inhibition regulation in hippocampal neurons. In juvenile Shisa7 knockout (KO) mice, α5-GABAAR-mediated tonic currents are significantly reduced. Mechanistically, Shisa7 is crucial for α5-GABAAR exocytosis. Additionally, Shisa7 regulation of tonic inhibition requires protein kinase A (PKA) that phosphorylates Shisa7 serine 405 (S405). Importantly, tonic inhibition undergoes activity-dependent regulation, and Shisa7 is required for homeostatic potentiation of tonic inhibition. Interestingly, in young adult Shisa7 KOs, basal tonic inhibition in hippocampal neurons is unaltered, largely due to the diminished α5-GABAAR component of tonic inhibition. However, at this stage, tonic inhibition oscillates during the daily sleep/wake cycle, a process requiring Shisa7. Together, these data demonstrate that intricate signaling mechanisms regulate tonic inhibition at different developmental stages and reveal a molecular link between sleep and tonic inhibition.
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Affiliation(s)
- Kunwei Wu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wenyan Han
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Qingjun Tian
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yan Li
- Proteomics Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wei Lu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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Schulte C, Maric HM. Expanding GABA AR pharmacology via receptor-associated proteins. Curr Opin Pharmacol 2021; 57:98-106. [PMID: 33684670 DOI: 10.1016/j.coph.2021.01.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 01/18/2021] [Accepted: 01/26/2021] [Indexed: 02/06/2023]
Abstract
Drugs directly targeting γ-aminobutyric acid type A receptors (GABAARs), the major mediators of fast synaptic inhibition, contribute significantly to today's neuropharmacology. Emerging evidence establishes intracellularly GABAAR-associated proteins as the central players in determining cellular and subcellular GABAergic input sites, thereby providing pharmacological opportunities to affect distinct receptor populations and address discrete neuronal dysfunctions. Here, we report on recently studied GABAAR-associated proteins and highlight challenges and newly available methods for their functional and physical mapping. We anticipate these efforts to contribute to decipher the complexity of GABAergic signalling in the brain and eventually enable therapeutic avenues for, so far, untreatable neuronal disorders and diseases.
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Affiliation(s)
- Clemens Schulte
- Department of Biotechnology and Biophysics and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Josef-Schneider-Str. 2, D15, 97080, Würzburg, Germany
| | - Hans Michael Maric
- Department of Biotechnology and Biophysics and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Josef-Schneider-Str. 2, D15, 97080, Würzburg, Germany.
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50
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George S, Chiou TT, Kanamalla K, De Blas AL. Recruitment of Plasma Membrane GABA-A Receptors by Submembranous Gephyrin/Collybistin Clusters. Cell Mol Neurobiol 2021; 42:1585-1604. [PMID: 33547626 DOI: 10.1007/s10571-021-01050-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/23/2021] [Indexed: 11/29/2022]
Abstract
It has been shown that subunit composition is the main determinant of the synaptic or extrasynaptic localization of GABAA receptors (GABAARs). Synaptic and extrasynaptic GABAARs are involved in phasic and tonic inhibition, respectively. It has been proposed that synaptic GABAARs bind to the postsynaptic gephyrin/collybistin (Geph/CB) lattice, but not the typically extrasynaptic GABAARs. Nevertheless, there are no studies of the direct binding of various types of GABAARs with the submembranous Geph/CB lattice in the absence of other synaptic proteins, some of which are known to interact with GABAARs. We have reconstituted GABAARs of various subunit compositions, together with the Geph/CB scaffold, in HEK293 cells, and have investigated the recruitment of surface GABAARs by submembranous Geph/CB clusters. Results show that the typically synaptic α1β3γ2 GABAARs were trapped by submembranous Geph/CB clusters. The α5β3γ2 GABAARs, which are both synaptic and extrasynaptic, were also trapped by Geph/CB clusters. Extrasynaptic α4β3δ GABAARs consistently showed little or no trapping by the Geph/CB clusters. However, the extrasynaptic α6β3δ, α1β3, α6β3 (and less α4β3) GABAARs were highly trapped by the Geph/CB clusters. AMPA and NMDA glutamate receptors were not trapped. The results suggest: (I) in the absence of other synaptic molecules, the Geph/CB lattice has the capacity to trap not only synaptic but also several typically extrasynaptic GABAARs; (II) the Geph/CB lattice is important but does not play a decisive role in the synaptic localization of GABAARs; and (III) in neurons there must be mechanisms preventing the trapping of several typically extrasynaptic GABAARs by the postsynaptic Geph/CB lattice.
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Affiliation(s)
- Shanu George
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, U-3156, Storrs, CT, 06269-3156, USA
| | - Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, U-3156, Storrs, CT, 06269-3156, USA
| | - Karthik Kanamalla
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, U-3156, Storrs, CT, 06269-3156, USA
| | - Angel L De Blas
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, U-3156, Storrs, CT, 06269-3156, USA.
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