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Pal I, Bhattacharyya A, V-Ghaffari B, Williams ED, Xiao M, Rutherford MA, Rubio ME. Female GluA3-KO mice show early onset hearing loss and afferent swellings in ambient sound levels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.21.581467. [PMID: 38659964 PMCID: PMC11042237 DOI: 10.1101/2024.02.21.581467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
AMPA-type glutamate receptors (AMPAR) mediate excitatory cochlear transmission. However, the unique roles of AMPAR subunits are unresolved. Lack of subunit GluA3 (Gria3KO) in male mice reduced cochlear output by 8-weeks of age. Since Gria3 is X-linked and considering sex differences in hearing vulnerability, we hypothesized accelerated presbycusis in Gria3KO females. Here, auditory brainstem responses (ABR) were similar in 3-week-old female Gria3WT and Gria3KO mice. However, when raised in ambient sound, ABR thresholds were elevated and wave-1 amplitudes were diminished at 5-weeks and older in Gria3KO. In contrast, these metrics were similar between genotypes when raised in quiet. Paired synapses were similar in number, but lone ribbons and ribbonless synapses were increased in female Gria3KO mice in ambient sound compared to Gria3WT or to either genotype raised in quiet. Synaptic GluA4:GluA2 ratios increased relative to Gria3WT, particularly in ambient sound, suggesting an activity-dependent increase in calcium-permeable AMPARs in Gria3KO. Swollen afferent terminals were observed by 5-weeks only in Gria3KO females reared in ambient sound. We propose that lack of GluA3 induces sex-dependent vulnerability to AMPAR-mediated excitotoxicity.
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Affiliation(s)
- Indra Pal
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Atri Bhattacharyya
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110
| | - Babak V-Ghaffari
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110
| | - Essence D. Williams
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Maolei Xiao
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110
| | - Mark A. Rutherford
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110
| | - María Eulalia Rubio
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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Huang L, Hardyman F, Edwards M, Galliano E. Deprivation-Induced Plasticity in the Early Central Circuits of the Rodent Visual, Auditory, and Olfactory Systems. eNeuro 2024; 11:ENEURO.0435-23.2023. [PMID: 38195533 PMCID: PMC11059429 DOI: 10.1523/eneuro.0435-23.2023] [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: 10/24/2023] [Revised: 12/07/2023] [Accepted: 12/12/2023] [Indexed: 01/11/2024] Open
Abstract
Activity-dependent neuronal plasticity is crucial for animals to adapt to dynamic sensory environments. Traditionally, it has been investigated using deprivation approaches in animal models primarily in sensory cortices. Nevertheless, emerging evidence emphasizes its significance in sensory organs and in subcortical regions where cranial nerves relay information to the brain. Additionally, critical questions started to arise. Do different sensory modalities share common cellular mechanisms for deprivation-induced plasticity at these central entry points? Does the deprivation duration correlate with specific plasticity mechanisms? This study systematically reviews and meta-analyzes research papers that investigated visual, auditory, or olfactory deprivation in rodents of both sexes. It examines the consequences of sensory deprivation in homologous regions at the first central synapse following cranial nerve transmission (vision - lateral geniculate nucleus and superior colliculus; audition - ventral and dorsal cochlear nucleus; olfaction - olfactory bulb). The systematic search yielded 91 papers (39 vision, 22 audition, 30 olfaction), revealing substantial heterogeneity in publication trends, experimental methods, measures of plasticity, and reporting across the sensory modalities. Despite these differences, commonalities emerged when correlating plasticity mechanisms with the duration of sensory deprivation. Short-term deprivation (up to 1 d) reduced activity and increased disinhibition, medium-term deprivation (1 d to a week) involved glial changes and synaptic remodeling, and long-term deprivation (over a week) primarily led to structural alterations. These findings underscore the importance of standardizing methodologies and reporting practices. Additionally, they highlight the value of cross-modal synthesis for understanding how the nervous system, including peripheral, precortical, and cortical areas, respond to and compensate for sensory inputs loss.
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Affiliation(s)
- Li Huang
- Department of Physiology, Development and Neuroscience, University of Cambridge, CB23EL Cambridge, United Kingdom
| | - Francesca Hardyman
- Department of Physiology, Development and Neuroscience, University of Cambridge, CB23EL Cambridge, United Kingdom
| | - Megan Edwards
- Department of Physiology, Development and Neuroscience, University of Cambridge, CB23EL Cambridge, United Kingdom
| | - Elisa Galliano
- Department of Physiology, Development and Neuroscience, University of Cambridge, CB23EL Cambridge, United Kingdom
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Eltokhi A, Bertocchi I, Rozov A, Jensen V, Borchardt T, Taylor A, Proenca CC, Rawlins JNP, Bannerman DM, Sprengel R. Distinct effects of AMPAR subunit depletion on spatial memory. iScience 2023; 26:108116. [PMID: 37876813 PMCID: PMC10590979 DOI: 10.1016/j.isci.2023.108116] [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: 10/25/2022] [Revised: 07/01/2023] [Accepted: 09/29/2023] [Indexed: 10/26/2023] Open
Abstract
Pharmacological studies established a role for AMPARs in the mammalian forebrain in spatial memory performance. Here we generated global GluA1/3 double knockout mice (Gria1/3-/-) and conditional knockouts lacking GluA1 and GluA3 AMPAR subunits specifically from principal cells across the forebrain (Gria1/3ΔFb). In both models, loss of GluA1 and GluA3 resulted in reduced hippocampal GluA2 and increased levels of the NMDAR subunit GluN2A. Electrically-evoked AMPAR-mediated EPSPs were greatly diminished, and there was an absence of tetanus-induced LTP. Gria1/3-/- mice showed premature mortality. Gria1/3ΔFb mice were viable, and their memory performance could be analyzed. In the Morris water maze (MWM), Gria1/3ΔFb mice showed profound long-term memory deficits, in marked contrast to the normal MWM learning previously seen in single Gria1-/- and Gria3-/- knockout mice. Our results suggest a redundancy of function within the pool of available ionotropic glutamate receptors for long-term spatial memory performance.
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Affiliation(s)
- Ahmed Eltokhi
- Departments of Molecular Neurobiology and Physiology, Max Planck Institute for Medical Research, Heidelberg, Germany
- Department of Pharmacolog, University of Washington, Seattle, WA, USA
| | - Ilaria Bertocchi
- Departments of Molecular Neurobiology and Physiology, Max Planck Institute for Medical Research, Heidelberg, Germany
- Department of Neuroscience Rita Levi Montalcini, University of Turin, 10126 Turin, Italy
- Neuroscience Institute - Cavalieri-Ottolenghi Foundation (NICO), Laboratory of Neuropsychopharmacology, Regione Gonzole 10, Orbassano, 10043 Torino, Italy
| | - Andrei Rozov
- Departments of Molecular Neurobiology and Physiology, Max Planck Institute for Medical Research, Heidelberg, Germany
- Institute of Neuroscience, Lobachevsky State University of Nizhniy, 603022 Novgorod, Russia
- Federal Center of Brain Research and Neurotechnology, 117997 Moscow, Russia
| | - Vidar Jensen
- Department of Molecular Medicine, Division of Physiology, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway
| | - Thilo Borchardt
- Departments of Molecular Neurobiology and Physiology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Amy Taylor
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Catia C. Proenca
- Departments of Molecular Neurobiology and Physiology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | | | | | - Rolf Sprengel
- Departments of Molecular Neurobiology and Physiology, Max Planck Institute for Medical Research, Heidelberg, Germany
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Rutherford MA, Bhattacharyya A, Xiao M, Cai HM, Pal I, Rubio ME. GluA3 subunits are required for appropriate assembly of AMPAR GluA2 and GluA4 subunits on cochlear afferent synapses and for presynaptic ribbon modiolar-pillar morphology. eLife 2023; 12:e80950. [PMID: 36648432 PMCID: PMC9891727 DOI: 10.7554/elife.80950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 01/16/2023] [Indexed: 01/18/2023] Open
Abstract
Cochlear sound encoding depends on α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs), but reliance on specific pore-forming subunits is unknown. With 5-week-old male C57BL/6J Gria3-knockout mice (i.e., subunit GluA3KO) we determined cochlear function, synapse ultrastructure, and AMPAR molecular anatomy at ribbon synapses between inner hair cells (IHCs) and spiral ganglion neurons. GluA3KO and wild-type (GluA3WT) mice reared in ambient sound pressure level (SPL) of 55-75 dB had similar auditory brainstem response (ABR) thresholds, wave-1 amplitudes, and latencies. Postsynaptic densities (PSDs), presynaptic ribbons, and synaptic vesicle sizes were all larger on the modiolar side of the IHCs from GluA3WT, but not GluA3KO, demonstrating GluA3 is required for modiolar-pillar synapse differentiation. Presynaptic ribbons juxtaposed with postsynaptic GluA2/4 subunits were similar in quantity, however, lone ribbons were more frequent in GluA3KO and GluA2-lacking synapses were observed only in GluA3KO. GluA2 and GluA4 immunofluorescence volumes were smaller on the pillar side than the modiolar side in GluA3KO, despite increased pillar-side PSD size. Overall, the fluorescent puncta volumes of GluA2 and GluA4 were smaller in GluA3KO than GluA3WT. However, GluA3KO contained less GluA2 and greater GluA4 immunofluorescence intensity relative to GluA3WT (threefold greater mean GluA4:GluA2 ratio). Thus, GluA3 is essential in development, as germline disruption of Gria3 caused anatomical synapse pathology before cochlear output became symptomatic by ABR. We propose the hearing loss in older male GluA3KO mice results from progressive synaptopathy evident in 5-week-old mice as decreased abundance of GluA2 subunits and an increase in GluA2-lacking, GluA4-monomeric Ca2+-permeable AMPARs.
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Affiliation(s)
- Mark A Rutherford
- Department of Otolaryngology, Washington University School of MedicineSt LouisUnited States
| | - Atri Bhattacharyya
- Department of Otolaryngology, Washington University School of MedicineSt LouisUnited States
| | - Maolei Xiao
- Department of Otolaryngology, Washington University School of MedicineSt LouisUnited States
| | - Hou-Ming Cai
- Department of Neurobiology, University of Pittsburgh School of MedicinePittsburghUnited States
| | - Indra Pal
- Department of Neurobiology, University of Pittsburgh School of MedicinePittsburghUnited States
| | - Maria Eulalia Rubio
- Department of Neurobiology, University of Pittsburgh School of MedicinePittsburghUnited States
- Department of Otolaryngology, University of Pittsburgh School of MedicinePittsburghUnited States
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Lozier NR, Muscio S, Pal I, Cai HM, Rubio ME. Sex differences in glutamate AMPA receptor subunits mRNA with fast gating kinetics in the mouse cochlea. Front Syst Neurosci 2023; 17:1100505. [PMID: 36936507 PMCID: PMC10017478 DOI: 10.3389/fnsys.2023.1100505] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 01/30/2023] [Indexed: 03/06/2023] Open
Abstract
Evidence shows that females have increased supra-threshold peripheral auditory processing compared to males. This is indicated by larger auditory brainstem responses (ABR) wave I amplitude, which measures afferent spiral ganglion neuron (SGN)-auditory nerve synchrony. However, the underlying molecular mechanisms of this sex difference are mostly unknown. We sought to elucidate sex differences in ABR wave I amplitude by examining molecular markers known to affect synaptic transmission kinetics. Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) mediate fast excitatory transmission in mature SGN afferent synapses. Each AMPAR channel is a tetramer composed of GluA2, 3, and 4 subunits (Gria2, 3, and 4 genes), and those lacking GluA2 subunits have larger currents, are calcium-permeable, and have faster gating kinetics. Moreover, alternatively spliced flip and flop isoforms of each AMPAR subunit affect channel kinetics, having faster kinetics those AMPARs containing Gria3 and Gria4 flop isoforms. We hypothesized that SGNs of females have more fast-gating AMPAR subunit mRNA than males, which could contribute to more temporally precise synaptic transmission and increased SGN synchrony. Our data show that the index of Gria3 relative to Gria2 transcripts on SGN was higher in females than males (females: 48%; males: 43%), suggesting that females have more SGNs with higher Gria3 mRNA relative to Gria2. Analysis of the relative abundance of the flip and flop alternatively spliced isoforms showed that females have a 2-fold increase in fast-gating Gria3 flop mRNA, while males have more slow-gating (2.5-fold) of the flip. We propose that Gria3 may in part mediate greater SGN synchrony in females. Significance Statement: Females of multiple vertebrate species, including fish and mammals, have been reported to have enhanced sound-evoked synchrony of afferents in the auditory nerve. However, the underlying molecular mediators of this physiologic sex difference are unknown. Elucidating potential molecular mechanisms related to sex differences in auditory processing is important for maintaining healthy ears and developing potential treatments for hearing loss in both sexes. This study found that females have a 2-fold increase in Gria3 flop mRNA, a fast-gating AMPA-type glutamate receptor subunit. This difference may contribute to greater neural synchrony in the auditory nerve of female mice compared to males, and this sex difference may be conserved in all vertebrates.
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Affiliation(s)
- Nicholas R. Lozier
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Steven Muscio
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Indra Pal
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Hou-Ming Cai
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
| | - María E. Rubio
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA, United States
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States
- *Correspondence: María E. Rubio
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Impaired Subcortical Processing of Amplitude-Modulated Tones in Mice Deficient for Cacna2d3, a Risk Gene for Autism Spectrum Disorders in Humans. eNeuro 2022; 9:ENEURO.0118-22.2022. [PMID: 35410870 PMCID: PMC9034753 DOI: 10.1523/eneuro.0118-22.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 03/21/2022] [Indexed: 12/18/2022] Open
Abstract
Temporal processing of complex sounds is a fundamental and complex task in hearing and a prerequisite for processing and understanding vocalization, speech, and prosody. Here, we studied response properties of neurons in the inferior colliculus (IC) in mice lacking Cacna2d3, a risk gene for autism spectrum disorders (ASDs). The α2δ3 auxiliary Ca2+ channel subunit encoded by Cacna2d3 is essential for proper function of glutamatergic synapses in the auditory brainstem. Recent evidence has shown that much of auditory feature extraction is performed in the auditory brainstem and IC, including processing of amplitude modulation (AM). We determined both spectral and temporal properties of single- and multi-unit responses in the IC of anesthetized mice. IC units of α2δ3−/− mice showed normal tuning properties yet increased spontaneous rates compared with α2δ3+/+. When stimulated with AM tones, α2δ3−/− units exhibited less precise temporal coding and reduced evoked rates to higher modulation frequencies (fm). Whereas first spike latencies (FSLs) were increased for only few modulation frequencies, population peak latencies were increased for fm ranging from 20 to 100 Hz in α2δ3−/− IC units. The loss of precision of temporal coding with increasing fm from 70 to 160 Hz was characterized using a normalized offset-corrected (Pearson-like) correlation coefficient, which appeared more appropriate than the metrics of vector strength. The processing deficits of AM sounds analyzed at the level of the IC indicate that α2δ3−/− mice exhibit a subcortical auditory processing disorder (APD). Similar deficits may be present in other mouse models for ASDs.
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García-Hernández S, Rubio ME. Role of GluA4 in the acoustic and tactile startle responses. Hear Res 2022; 414:108410. [PMID: 34915397 PMCID: PMC8776314 DOI: 10.1016/j.heares.2021.108410] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 08/26/2021] [Accepted: 12/06/2021] [Indexed: 02/03/2023]
Abstract
The primary startle response (SR) is an innate reaction evoked by sudden and intense acoustic, tactile or visual stimuli. In rodents and humans the SR involves reflexive contractions of the face, neck and limb muscles. The acoustic startle response (ASR) pathway consists of auditory nerve fibers (AN), cochlear root neurons (CRNs) and giant neurons of the caudal pontine reticular nucleus (PnC), which synapse on cranial and spinal motor neurons. The tactile startle response (TSR) is transmitted by primary sensory neurons to the principal sensory (Pr5) and spinal (Sp5) trigeminal nuclei. The ventral part of Pr5 projects directly to the PnC neurons. The SR requires rapid transmission of sensory information to initiate a fast motor response. Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) are necessary to transmit auditory information to the PnC neurons and elicit the SR. AMPARs containing the glutamate AMPAR subunit 4 (GluA4) have fast kinetics, which makes them ideal candidates to transmit the SR signal. This study examined the role of GluA4 within the primary SR pathway by using GluA4 knockout (GluA4-KO) mice. Deletion of GluA4 considerably decreased the amplitude and probability of successful ASR and TSR, indicating that the presence of this subunit is critical at a common station within the startle pathway. We conclude that deletion of GluA4 affects the transmission of sensory signals from acoustic and tactile pathways to the motor component of the startle reflex. Therefore, GluA4 is required for the full response and for reliable elicitation of the startle response.
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Affiliation(s)
- Sofía García-Hernández
- Corresponding authors. Sofía García-Hernández, María E. Rubio, Departments of Neurobiology and Otolaryngology, University of Pittsburgh Medical School, BST3 Building, 3501 Fifth Avenue #10016, Pittsburgh, PA 15261, ,
| | - María E. Rubio
- Corresponding authors. Sofía García-Hernández, María E. Rubio, Departments of Neurobiology and Otolaryngology, University of Pittsburgh Medical School, BST3 Building, 3501 Fifth Avenue #10016, Pittsburgh, PA 15261, ,
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Martinez-Esteve Melnikova A, Pijuan J, Aparicio J, Ramírez A, Altisent-Huguet A, Vilanova-Adell A, Arzimanoglou A, Armstrong J, Palau F, Hoenicka J, San Antonio-Arce V. The p.Glu787Lys variant in the GRIA3 gene causes developmental and epileptic encephalopathy mimicking structural epilepsy in a female patient. Eur J Med Genet 2022; 65:104442. [DOI: 10.1016/j.ejmg.2022.104442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/28/2021] [Accepted: 01/22/2022] [Indexed: 11/03/2022]
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Italia M, Ferrari E, Di Luca M, Gardoni F. GluA3-containing AMPA receptors: From physiology to synaptic dysfunction in brain disorders. Neurobiol Dis 2021; 161:105539. [PMID: 34743951 DOI: 10.1016/j.nbd.2021.105539] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/01/2021] [Accepted: 10/27/2021] [Indexed: 01/03/2023] Open
Abstract
In the mammalian brain, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors (AMPARs) play a fundamental role in the activation of excitatory synaptic transmission and the induction of different forms of synaptic plasticity. The modulation of the AMPAR tetramer subunit composition at synapses defines the functional properties of the receptor. During the last twenty years, several studies have evaluated the roles played by each subunit, from GluA1 to GluA4, in both physiological and pathological conditions. Here, we have focused our attention on GluA3-containing AMPARs, addressing their functional role in synaptic transmission and synaptic plasticity and their involvement in a variety of brain disorders. Although several aspects remain to be fully understood, GluA3 is a widely expressed and functionally relevant subunit in AMPARs involved in several brain circuits, and its pharmacological modulation could represent a novel approach for the rescue of altered glutamatergic synapses associated with neurodegenerative and neurodevelopmental disorders.
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Affiliation(s)
- Maria Italia
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), University of Milan, 20133 Milan, Italy
| | - Elena Ferrari
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), University of Milan, 20133 Milan, Italy
| | - Monica Di Luca
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), University of Milan, 20133 Milan, Italy
| | - Fabrizio Gardoni
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), University of Milan, 20133 Milan, Italy.
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Enache D, Pereira JB, Jelic V, Winblad B, Nilsson P, Aarsland D, Bereczki E. Increased Cerebrospinal Fluid Concentration of ZnT3 Is Associated with Cognitive Impairment in Alzheimer's Disease. J Alzheimers Dis 2021; 77:1143-1155. [PMID: 32925049 DOI: 10.3233/jad-200498] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Cognitive deficits arising in the course of Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and Parkinson's disease with dementia (PDD) are directly linked to synaptic loss. Postmortem studies suggest that zinc transporter protein 3 (ZnT3), AMPA glutamate receptor 3 (GluA3), and Dynamin1 are associated with cognitive decline in AD and Lewy body dementia patients. OBJECTIVE We aimed to evaluate the diagnostic value of ZnT3, GluA3, and Dynamin 1 in the cerebrospinal fluid (CSF) of patients with dementia due to AD, DLB, and PDD compared to cognitively normal subjective cognitive decline (SCD) patients in a retrospective study. In addition, we assessed the relationship between synaptic markers and age, sex, cognitive impairment, and depressive symptoms as well as CSF amyloid, phosphorylated tau (p-tau), and total tau (T-tau). METHODS Commercially available ELISA immunoassay was used to measure the levels of proteins in a total of 97 CSF samples from AD (N = 24), PDD (N = 18), DLB (N = 27), and SCD (N = 28) patients. Cognitive impairment was assessed using the Mini-Mental State Examination (MMSE). RESULTS We found a significant increase in the concentrations of ZnT3, GluA3, and Dynamin1 in AD (p = 0.002) and of ZnT3 and Dynamin 1 in DLB (p = 0.001, p = 0.002) when compared to SCD patients. Changes in ZnT3 concentrations correlated with MMSE scores in AD (p = 0.011), and with depressive symptoms in SCD (p = 0.041). CONCLUSION We found alteration of CSF levels of synaptic proteins in AD, PDD, and DLB. Our results reveal distinct changes in CSF concentrations of ZnT3 that could reflect cognitive impairment in AD with implications for future prognostic and diagnostic marker development.
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Affiliation(s)
- Daniela Enache
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden
| | - Joana B Pereira
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Clinical Geriatrics, Karolinska Institutet, Stockholm, Sweden
| | - Vesna Jelic
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Clinical Geriatrics, Karolinska Institutet, Stockholm, Sweden
| | - Bengt Winblad
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden
| | - Per Nilsson
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden
| | - Dag Aarsland
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden.,Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Centre for Age-Related Medicine, Stavanger University Hospital, Stavanger, Norway
| | - Erika Bereczki
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden
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Gugustea R, Jia Z. Genetic manipulations of AMPA glutamate receptors in hippocampal synaptic plasticity. Neuropharmacology 2021; 194:108630. [PMID: 34089730 DOI: 10.1016/j.neuropharm.2021.108630] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 05/06/2021] [Accepted: 05/18/2021] [Indexed: 01/17/2023]
Abstract
Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are the principal mediators of fast excitatory synaptic transmission and they are required for various forms of synaptic plasticity, including long-term potentiation (LTP) and depression (LTD), which are key mechanisms of learning and memory. AMPARs are tetrameric complexes assembled from four subunits (GluA1-4), however, the lack of subunit-specific pharmacological tools has made the assessment of individual subunits difficult. The application of genetic techniques, particularly gene targeting, allows for precise manipulation and dissection of each subunit in the regulation of neuronal function and behaviour. In this review, we summarize studies using various mouse models with genetically altered AMPARs and focus on their roles in basal synaptic transmission, LTP, and LTD at the hippocampal CA1 synapse. These studies provide strong evidence that there are multiple forms of LTP and LTD at this synapse which can be induced by various induction protocols, and they are differentially regulated by different AMPAR subunits and domains. We conclude that it is necessary to delineate the mechanism of each of these forms of plasticity and their contribution to memory and brain disorders.
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Affiliation(s)
- Radu Gugustea
- The Hospital for Sick Children, Neurosciences and Mental Health Program, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada; Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Zhengping Jia
- The Hospital for Sick Children, Neurosciences and Mental Health Program, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada; Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
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Hintze A, Gültas M, Semmelhack EA, Wichmann C. Ultrastructural maturation of the endbulb of Held active zones comparing wild-type and otoferlin-deficient mice. iScience 2021; 24:102282. [PMID: 33851098 PMCID: PMC8022229 DOI: 10.1016/j.isci.2021.102282] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 01/18/2021] [Accepted: 03/03/2021] [Indexed: 11/13/2022] Open
Abstract
Endbulbs of Held are located in the anteroventral cochlear nucleus and present the first central synapses of the auditory pathway. During development, endbulbs mature functionally to enable rapid and powerful synaptic transmission with high temporal precision. This process is accompanied by morphological changes of endbulb terminals. Loss of the hair cell-specific protein otoferlin (Otof) abolishes neurotransmission in the cochlea and results in the smaller endbulb of Held terminals. Thus, peripheral hearing impairment likely also leads to alterations in the morphological synaptic vesicle (SV) pool size at individual endbulb of Held active zones (AZs). Here, we investigated endbulb AZs in pre-hearing, young, and adult wild-type and Otof−/− mice. During maturation, SV numbers at endbulb AZs increased in wild-type mice but were found to be reduced in Otof−/− mice. The SV population at a distance of 0–15 nm was most strongly affected. Finally, overall SV diameters decreased in Otof−/− animals during maturation. Maturation of wt endbulb of Held active zones leads to more synaptic vesicles At endbulbs of otoferlin knockout mice, synaptic vesicles decline with age Mainly two distinct synaptic vesicle populations are affected Synaptic vesicles sizes are reduced in six-month-old otoferlin knockout animals
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Affiliation(s)
- Anika Hintze
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience, InnerEarLab and Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany.,Collaborative Research Center 1286, University of Göttingen, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Mehmet Gültas
- Breeding Informatics Group, Department of Animal Sciences, Georg-August-University Göttingen, Göttingen, Germany
| | - Esther A Semmelhack
- Developmental, Neural, and Behavioral Biology MSc/PhD Program, University of Göttingen, Göttingen, Germany
| | - Carolin Wichmann
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience, InnerEarLab and Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany.,Collaborative Research Center 1286, University of Göttingen, Göttingen, Germany
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13
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Mechanisms and Functional Consequences of Presynaptic Homeostatic Plasticity at Auditory Nerve Synapses. J Neurosci 2020; 40:6896-6909. [PMID: 32747441 DOI: 10.1523/jneurosci.1175-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 07/24/2020] [Accepted: 07/28/2020] [Indexed: 01/21/2023] Open
Abstract
Multiple forms of homeostasis influence synaptic function under diverse activity conditions. Both presynaptic and postsynaptic forms of homeostasis are important, but their relative impact on fidelity is unknown. To address this issue, we studied auditory nerve synapses onto bushy cells in the cochlear nucleus of mice of both sexes. These synapses undergo bidirectional presynaptic and postsynaptic homeostatic changes with increased and decreased acoustic stimulation. We found that both young and mature synapses exhibit similar activity-dependent changes in short-term depression. Experiments using chelators and imaging both indicated that presynaptic Ca2+ influx decreased after noise exposure, and increased after ligating the ear canal. By contrast, Ca2+ cooperativity was unaffected. Experiments using specific antagonists suggest that occlusion leads to changes in the Ca2+ channel subtypes driving neurotransmitter release. Furthermore, dynamic-clamp experiments revealed that spike fidelity primarily depended on changes in presynaptic depression, with some contribution from changes in postsynaptic intrinsic properties. These experiments indicate that presynaptic Ca2+ influx is homeostatically regulated in vivo to enhance synaptic fidelity.SIGNIFICANCE STATEMENT Homeostatic mechanisms in synapses maintain stable function in the face of different levels of activity. Both juvenile and mature auditory nerve synapses onto bushy cells modify short-term depression in different acoustic environments, which raises the question of what the underlying presynaptic mechanisms are and the relative importance of presynaptic and postsynaptic contributions to the faithful transfer of information. Changes in short-term depression under different acoustic conditions were a result of changes in presynaptic Ca2+ influx. Spike fidelity was affected by both presynaptic and postsynaptic changes after ear occlusion and was only affected by presynaptic changes after noise-rearing. These findings are important for understanding regulation of auditory synapses under normal conditions and also in disorders following noise exposure or conductive hearing loss.
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14
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Transient Conductive Hearing Loss Regulates Cross-Modal VGLUT Expression in the Cochlear Nucleus of C57BL/6 Mice. Brain Sci 2020; 10:brainsci10050260. [PMID: 32365514 PMCID: PMC7287693 DOI: 10.3390/brainsci10050260] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 12/19/2022] Open
Abstract
Auditory nerve fibers synapse onto the cochlear nucleus (CN) and are labeled using the vesicular glutamate transporter-1 (VGLUT-1), whereas non-auditory inputs are labeled using the VGLUT-2. However, the underlying regulatory mechanism of VGLUT expression in the CN remains unknown. We examined whether a sound level decrease, without primary neural damage, induces cellular and VGLUT expression change in the CN, and examined the potential for neural plasticity of the CN using unilateral conductive hearing loss models. We inserted earplugs in 8-week-old mice unilaterally for 4 weeks and subsequently removed them for another 4 weeks. Although the threshold of an auditory brainstem response significantly increased across all tested frequencies following earplug insertion, it completely recovered after earplug removal. Auditory deprivation had no significant impact on spiral ganglion and ventral CN (VCN) neurons’ survival. Conversely, although the cell size and VGLUT-1 expression in the VCN significantly decreased after earplug insertion, VGLUT-2 expression in the granule cell lamina significantly increased. These cell sizes decreased and the alterations in VGLUT-1 and -2 expression almost completely recovered at 1 month after earplug removal. Our results suggested that the cell size and VGLUT expression in the CN have a neuroplasticity capacity, which is regulated by increases and decreases in sound levels. Restoration of the sound levels might partly prevent cell size decrease and maintain VGLUT expression in the CN.
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15
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Role of GluA3 AMPA Receptor Subunits in the Presynaptic and Postsynaptic Maturation of Synaptic Transmission and Plasticity of Endbulb-Bushy Cell Synapses in the Cochlear Nucleus. J Neurosci 2020; 40:2471-2484. [PMID: 32051325 DOI: 10.1523/jneurosci.2573-19.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/22/2020] [Accepted: 02/02/2020] [Indexed: 11/21/2022] Open
Abstract
The AMPA receptor (AMPAR) subunit GluA3 has been suggested to shape synaptic transmission and activity-dependent plasticity in endbulb-bushy cell synapses (endbulb synapses) in the anteroventral cochlear nucleus, yet the specific roles of GluA3 in the synaptic transmission at endbulb synapses remains unexplored. Here, we compared WT and GluA3 KO mice of both sexes and identified several important roles of GluA3 in the maturation of synaptic transmission and short-term plasticity in endbulb synapses. We show that GluA3 largely determines the ultrafast kinetics of endbulb synapses glutamatergic currents by promoting the insertion of postsynaptic AMPARs that contain fast desensitizing flop subunits. In addition, GluA3 is also required for the normal function, structure, and development of the presynaptic terminal which leads to altered short term-depression in GluA3 KO mice. The presence of GluA3 reduces and slows synaptic depression, which is achieved by lowering the probability of vesicle release, promoting efficient vesicle replenishment, and increasing the readily releasable pool of synaptic vesicles. Surprisingly, GluA3 also makes the speed of synaptic depression rate-invariant. We propose that the slower and rate-invariant speed of depression allows an initial response window that still contains presynaptic firing rate information before the synapse is depressed. Because this response window is rate-invariant, GluA3 extends the range of presynaptic firing rates over which rate information in bushy cells can be preserved. This novel role of GluA3 may be important to allowing the postsynaptic targets of spherical bushy cells in mice use rate information for encoding sound intensity and sound localization.SIGNIFICANCE STATEMENT We report novel roles of the glutamate receptor subunit GluA3 in synaptic transmission in synapses between auditory nerve fibers and spherical bushy cells (BCs) in the cochlear nucleus. We show that GluA3 contributes to the generation of ultrafast glutamatergic currents at these synapses, which is important to preserve temporal information about the sound. Furthermore, we demonstrate that GluA3 contributes to the normal function and development of the presynaptic terminal, whose properties shape short-term plasticity. GluA3 slows and attenuates synaptic depression, and makes it less dependent on the presynaptic firing rates. This may help BCs to transfer information about the high rates of activity that occur at the synapse in vivo to postsynaptic targets that use rate information for sound localization.
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16
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Renner MC, Albers EH, Gutierrez-Castellanos N, Reinders NR, van Huijstee AN, Xiong H, Lodder TR, Kessels HW. Synaptic plasticity through activation of GluA3-containing AMPA-receptors. eLife 2017; 6:25462. [PMID: 28762944 PMCID: PMC5578739 DOI: 10.7554/elife.25462] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 07/31/2017] [Indexed: 11/13/2022] Open
Abstract
Excitatory synaptic transmission is mediated by AMPA-type glutamate receptors (AMPARs). In CA1 pyramidal neurons of the hippocampus two types of AMPARs predominate: those that contain subunits GluA1 and GluA2 (GluA1/2), and those that contain GluA2 and GluA3 (GluA2/3). Whereas subunits GluA1 and GluA2 have been extensively studied, the contribution of GluA3 to synapse physiology has remained unclear. Here we show in mice that GluA2/3s are in a low-conductance state under basal conditions, and although present at synapses they contribute little to synaptic currents. When intracellular cyclic AMP (cAMP) levels rise, GluA2/3 channels shift to a high-conductance state, leading to synaptic potentiation. This cAMP-driven synaptic potentiation requires the activation of both protein kinase A (PKA) and the GTPase Ras, and is induced upon the activation of β-adrenergic receptors. Together, these experiments reveal a novel type of plasticity at CA1 hippocampal synapses that is expressed by the activation of GluA3-containing AMPARs.
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Affiliation(s)
- Maria C Renner
- Synaptic Plasticity and Behavior Group, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Eva Hh Albers
- Synaptic Plasticity and Behavior Group, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Nicolas Gutierrez-Castellanos
- Synaptic Plasticity and Behavior Group, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Niels R Reinders
- Synaptic Plasticity and Behavior Group, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Aile N van Huijstee
- Synaptic Plasticity and Behavior Group, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Hui Xiong
- Synaptic Plasticity and Behavior Group, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Tessa R Lodder
- Synaptic Plasticity and Behavior Group, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Helmut W Kessels
- Synaptic Plasticity and Behavior Group, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
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