1
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Gao M, Wang K, Zhao H. GABAergic neurons maturation is regulated by a delicate network. Int J Dev Neurosci 2023; 83:3-15. [PMID: 36401305 DOI: 10.1002/jdn.10242] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 10/25/2022] [Accepted: 11/13/2022] [Indexed: 11/21/2022] Open
Abstract
Gamma-aminobutyric acid-expressing (GABAergic) neurons are implicated in a variety of neuropsychiatric disorders, such as epilepsy, anxiety, autism, and other pathological processes, including cerebral ischemia injury and drug addiction. Therefore, GABAergic neuronal processes warrant further research. The development of GABAergic neurons is a tightly controlled process involving the activity of multiple transcription and growth factors. Here, we focus on the gene expression pathways and the molecular modulatory networks that are engaged during the development of GABAergic neurons with the goal of exploring regulatory mechanisms that influence GABAergic neuron fate (i.e., maturation). Overall, we hope to provide a basis for clarifying the pathogenesis of neurodegenerative disorders.
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Affiliation(s)
- Mingxing Gao
- Department of Histology and Embryology, School of Basic Medical Science, Jilin University, Changchun, Jilin, China
| | - Kaizhong Wang
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Hui Zhao
- Department of Histology and Embryology, School of Basic Medical Science, Jilin University, Changchun, Jilin, China
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2
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Edwards-Faret G, de Vin F, Slezak M, Gollenbeck L, Karaman R, Shinmyo Y, Batiuk MY, Pando CM, Urschitz J, Rincon MY, Moisyadi S, Schnütgen F, Kawasaki H, Schmucker D, Holt MG. A New Technical Approach for Cross-species Examination of Neuronal Wiring and Adult Neuron-glia Functions. Neuroscience 2023; 508:40-51. [PMID: 36464177 DOI: 10.1016/j.neuroscience.2022.11.029] [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: 03/21/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 12/03/2022]
Abstract
Advances in single cell sequencing have enabled the identification of a large number of genes, expressed in many different cell types, and across a variety of model organisms. In particular, the nervous system harbors an immense number of interacting cell types, which are poorly characterized. Future loss- and gain-of-function experiments will be essential in determining how novel genes play critical roles in diverse cellular, as well as evolutionarily adapted, contexts. However, functional analysis across species is often hampered by technical limitations, in non-genetic animal systems. Here, we describe a new single plasmid system, misPiggy. The system is based around the hyperactive piggyBac transposon system, which combines stable genomic integration of transgenes (for long-term expression) with large cargo capacity. Taking full advantage of these characteristics, we engineered novel expression modules into misPiggy that allow for cell-type specific loss- and gain-of-gene function. These modules work widely across species from frog to ferret. As a proof of principle, we present a loss-of-function analysis of the neuronal receptor Deleted in Colorectal Cancer (DCC) in retinal ganglion cells (RGCs) of Xenopus tropicalis tadpoles. Single axon tracings of mosaic knock-out cells reveal a specific cell-intrinsic requirement of DCC, specifically in axonal arborization within the frog tectum, rather than retina-to-brain axon guidance. Furthermore, we report additional technical advances that enable temporal control of knock-down or gain-of-function analysis. We applied this to visualize and manipulate labeled neurons, astrocytes and other glial cells in the central nervous system (CNS) of mouse, rat and ferret. We propose that misPiggy will be a valuable tool for rapid, flexible and cost-effective screening of gene function across a variety of animal models.
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Affiliation(s)
- Gabriela Edwards-Faret
- VIB Center for Brain and Disease Research, Herestraat 49, Leuven 3000, Belgium; KU Leuven Department of Neuroscience, Herestraat 49, Leuven 3000, Belgium; Neuronal Wiring Group, Life & Medical Sciences Institute, University of Bonn, Carl-Troll-Straße 31, Bonn D53115, Germany
| | - Filip de Vin
- VIB Center for Brain and Disease Research, Herestraat 49, Leuven 3000, Belgium; KU Leuven Department of Neuroscience, Herestraat 49, Leuven 3000, Belgium
| | - Michal Slezak
- VIB Center for Brain and Disease Research, Herestraat 49, Leuven 3000, Belgium; KU Leuven Department of Neuroscience, Herestraat 49, Leuven 3000, Belgium
| | - Lennart Gollenbeck
- Neuronal Wiring Group, Life & Medical Sciences Institute, University of Bonn, Carl-Troll-Straße 31, Bonn D53115, Germany
| | - Ruçhan Karaman
- VIB Center for Cancer Biology, Herestraat 49, Leuven 3000, Belgium; KU Leuven Department of Oncology, Herestraat 49, Leuven 3000, Belgium
| | - Yohei Shinmyo
- Department of Medical Neuroscience, Graduate School of Medicine, Kanazawa University, Ishikawa 920-1192, Japan
| | - Mykhailo Y Batiuk
- VIB Center for Brain and Disease Research, Herestraat 49, Leuven 3000, Belgium; KU Leuven Department of Neuroscience, Herestraat 49, Leuven 3000, Belgium
| | - Carmen Menacho Pando
- VIB Center for Brain and Disease Research, Herestraat 49, Leuven 3000, Belgium; KU Leuven Department of Neuroscience, Herestraat 49, Leuven 3000, Belgium
| | - Johann Urschitz
- Institute for Biogenesis Research, University of Hawaii, 1960 East-West Rd. E-124, Honolulu, HI 96822, USA
| | - Melvin Y Rincon
- VIB Center for Brain and Disease Research, Herestraat 49, Leuven 3000, Belgium; KU Leuven Department of Neuroscience, Herestraat 49, Leuven 3000, Belgium
| | - Stefan Moisyadi
- Institute for Biogenesis Research, University of Hawaii, 1960 East-West Rd. E-124, Honolulu, HI 96822, USA
| | - Frank Schnütgen
- Department of Medicine 2, University Hospital Frankfurt, Goethe University, Theodor Stern Kai 7, Frankfurt am Main D60590, Germany; LOEWE Center for Cell and Gene Therapy, University Hospital Frankfurt, Goethe University, Theodor Stern Kai 7, Frankfurt am Main D60590, Germany; FCI, Frankfurt Cancer Institute, University Hospital Frankfurt, Goethe University, Theodor Stern Kai 7, Frankfurt am Main D60590, Germany
| | - Hiroshi Kawasaki
- Department of Medical Neuroscience, Graduate School of Medicine, Kanazawa University, Ishikawa 920-1192, Japan
| | - Dietmar Schmucker
- VIB Center for Brain and Disease Research, Herestraat 49, Leuven 3000, Belgium; KU Leuven Department of Neuroscience, Herestraat 49, Leuven 3000, Belgium; Neuronal Wiring Group, Life & Medical Sciences Institute, University of Bonn, Carl-Troll-Straße 31, Bonn D53115, Germany; Leuven Brain Institute, Herestraat 49, Leuven 3000, Belgium.
| | - Matthew G Holt
- VIB Center for Brain and Disease Research, Herestraat 49, Leuven 3000, Belgium; KU Leuven Department of Neuroscience, Herestraat 49, Leuven 3000, Belgium; Leuven Brain Institute, Herestraat 49, Leuven 3000, Belgium; University of Porto, Instituto de Investigaçāo e Inovaçāo em Saúde (i3S), Rua Alfredo Allen 208, 4200-135 Porto, Portugal.
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3
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Bhimani RV, Yates R, Bass CE, Park J. Distinct limbic dopamine regulation across olfactory-tubercle subregions through integration of in vivo fast-scan cyclic voltammetry and optogenetics. J Neurochem 2022; 161:53-68. [PMID: 35061915 PMCID: PMC8930533 DOI: 10.1111/jnc.15577] [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: 10/28/2021] [Revised: 12/20/2021] [Accepted: 01/17/2022] [Indexed: 11/29/2022]
Abstract
The olfactory tubercle (OT), an important component of the ventral striatum and limbic system, is involved in multi-sensory integration of reward-related information in the brain. However, its functional roles are often overshadowed by the neighboring nucleus accumbens. Increasing evidence has highlighted that dense dopamine (DA) innervation of the OT from the ventral tegmental area (VTA) is implicated in encoding reward, natural reinforcers, and motivated behaviors. Recent studies have further suggested that OT subregions may have distinct roles in these processes due to their heterogeneous DA transmission. Currently, very little is known about regulation (release and clearance) of extracellular DA across OT subregions due to its limited anatomical accessibility and proximity to other DA-rich brain regions, making it difficult to isolate VTA-DA signaling in the OT with conventional methods. Herein, we characterized heterogeneous VTA-DA regulation in the medial (m) and lateral (l) OT in "wild-type," urethane-anesthetized rats by integrating in vivo fast-scan cyclic voltammetry with cell-type specific optogenetics to stimulate VTA-DA neurons. Channelrhodopsin-2 was selectively expressed in the VTA-DA neurons of wild-type rats and optical stimulating parameters were optimized to determine VTA-DA transmission across the OT. Our anatomical, neurochemical, and pharmacological results show that VTA-DA regulation in the mOT is less dependent on DA transporters and has greater DA transmission than the lOT. These findings establish the OT as a unique, compartmentalized structure and will aid in future behavioral characterization of the roles of VTA-DA signaling in the OT subregions in reward, drug addiction, and encoding behavioral outputs necessary for survival.
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Affiliation(s)
- Rohan V. Bhimani
- Neuroscience Program, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
- Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
| | - Ryan Yates
- Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
| | - Caroline E. Bass
- Neuroscience Program, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
- Department of Pharmacology and Toxicology, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
| | - Jinwoo Park
- Neuroscience Program, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
- Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
- Department of Pharmacology and Toxicology, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
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Selective Overexpression of Collybistin in Mouse Hippocampal Pyramidal Cells Enhances GABAergic Neurotransmission and Protects against PTZ-Induced Seizures. eNeuro 2021; 8:ENEURO.0561-20.2021. [PMID: 34083383 PMCID: PMC8281261 DOI: 10.1523/eneuro.0561-20.2021] [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: 12/27/2020] [Revised: 04/02/2021] [Accepted: 05/23/2021] [Indexed: 11/21/2022] Open
Abstract
Collybistin (CB) is a rho guanine exchange factor found at GABAergic and glycinergic postsynapses that interacts with the inhibitory scaffold protein, gephyrin, and induces accumulation of gephyrin and GABA type-A receptors (GABAARs) to the postsynapse. We have previously reported that the isoform without the src homology 3 (SH3) domain, CBSH3-, is particularly active in enhancing the GABAergic postsynapse in both cultured hippocampal neurons as well as in cortical pyramidal neurons after chronic in vivo expression in in utero electroporated (IUE) rats. Deficiency of CB in knock-out (KO) mice results in absence of gephyrin and gephyrin-dependent GABAARs at postsynaptic sites in several brain regions, including hippocampus. In the present study, we have generated an adeno-associated virus (AAV) that expresses CBSH3- in a cre-dependent manner. Using male and female VGLUT1-IRES-cre or VGAT-IRES-cre mice, we explore the effect of overexpression of CBSH3- in hippocampal pyramidal cells or hippocampal interneurons. The results show that: (1) the accumulation of gephyrin and GABAARs at inhibitory postsynapses in hippocampal pyramidal neurons or interneurons can be enhanced by CBSH3- overexpression; (2) overexpression of CBSH3- in hippocampal pyramidal cells can enhance the strength of inhibitory neurotransmission; and (3) these enhanced inhibitory synapses provide protection against pentylenetetrazole (PTZ)-induced seizures. The results indicate that this AAV vector carrying CBSH3- can be used for in vivo enhancement of GABAergic synaptic transmission in selected target neurons in the brain.
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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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6
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George S, Bear J, Taylor MJ, Kanamalla K, Fekete CD, Chiou TT, Miralles CP, Papadopoulos T, De Blas AL. Collybistin SH3-protein isoforms are expressed in the rat brain promoting gephyrin and GABA-A receptor clustering at GABAergic synapses. J Neurochem 2021; 157:1032-1051. [PMID: 33316079 DOI: 10.1111/jnc.15270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/18/2020] [Accepted: 12/08/2020] [Indexed: 01/21/2023]
Abstract
Collybistin (CB) is a guanine nucleotide exchange factor (GEF) selectively localized at GABAergic and glycinergic postsynapses. Analysis of mRNA shows that several isoforms of collybistin are expressed in the brain. Some of the isoforms have a SH3 domain (CBSH3+) and some have no SH3 domain (CBSH3-). The CBSH3+ mRNAs are predominantly expressed over CBSH3-. However, in an immunoblot study of mouse brain homogenates, only CBSH3+ protein isoforms were detected, proposing that CBSH3- protein might not be expressed in the brain. The expression or lack of expression of CBSH3- protein is an important issue because CBSH3- has a strong effect in promoting the postsynaptic clustering of gephyrin and GABA-A receptors (GABAA Rs). Moreover CBSH3- is constitutively active; therefore lower expression of CBSH3- protein might play a relatively stronger functional role than the more abundant but self-inhibited CBSH3+ isoforms, which need to be activated. We are now showing that: (a) CBSH3- protein is expressed in the brain; (b) parvalbumin positive (PV+) interneurons show higher expression of CBSH3- protein than other neurons; (c) CBSH3- is associated with GABAergic synapses in various regions of the brain and (d) knocking down CBSH3- in hippocampal neurons decreases the synaptic clustering of gephyrin and GABAA Rs. The results show that CBSH3- protein is expressed in the brain and that it plays a significant role in the size regulation of the GABAergic postsynapse.
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Affiliation(s)
- Shanu George
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - John Bear
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Michael J Taylor
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Karthik Kanamalla
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Christopher D Fekete
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Celia P Miralles
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | | | - Angel L De Blas
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
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7
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Chang GQ, Karatayev O, Boorgu DSSK, Leibowitz SF. Third Ventricular Injection of CCL2 in Rat Embryo Stimulates CCL2/CCR2 Neuroimmune System in Neuroepithelial Radial Glia Progenitor Cells: Relation to Sexually Dimorphic, Stimulatory Effects on Peptide Neurons in Lateral Hypothalamus. Neuroscience 2020; 443:188-205. [PMID: 31982472 PMCID: PMC7681774 DOI: 10.1016/j.neuroscience.2020.01.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 02/06/2023]
Abstract
Clinical and animal studies show maternal alcohol consumption during pregnancy causes in offspring persistent alterations in neuroimmune and neurochemical systems known to increase alcohol drinking and related behaviors. Studies in lateral hypothalamus (LH) demonstrate in adolescent offspring that maternal oral administration of ethanol stimulates the neuropeptide, melanin-concentrating hormone (MCH), together with the inflammatory chemokine C-C motif ligand 2 (CCL2) and its receptor CCR2 which are increased in most MCH neurons. These effects, consistently stronger in females than males, are detected in embryos, not only in LH but hypothalamic neuroepithelium (NEP) along the third ventricle where neurons are born and CCL2 is stimulated within radial glia progenitor cells and their laterally projecting processes that facilitate MCH neuronal migration toward LH. With ethanol's effects similarly produced by maternal peripheral CCL2 administration and blocked by CCR2 antagonist, we tested here using in utero intracerebroventricular (ICV) injections whether CCL2 acts locally within the embryonic NEP. After ICV injection of CCL2 (0.1 µg/µl) on embryonic day 14 (E14) when neurogenesis peaks, we observed in embryos just before birth (E19) a significant increase in endogenous CCL2 within radial glia cells and their processes in NEP. These auto-regulatory effects, evident only in female embryos, were accompanied by increased density of CCL2 and MCH neurons in LH, more strongly in females than males. These results support involvement of embryonic CCL2/CCR2 neuroimmune system in radial glia progenitor cells in mediating sexually dimorphic effects of maternal challenges such as ethanol on LH MCH neurons that colocalize CCL2 and CCR2.
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Miralles CP, Taylor MJ, Bear J, Fekete CD, George S, Li Y, Bonhomme B, Chiou TT, De Blas AL. Expression of protocadherin-γC4 protein in the rat brain. J Comp Neurol 2019; 528:840-864. [PMID: 31609469 DOI: 10.1002/cne.24783] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/24/2019] [Accepted: 09/30/2019] [Indexed: 12/26/2022]
Abstract
It has been proposed that the combinatorial expression of γ-protocadherins (Pcdh-γs) and other clustered protocadherins (Pcdhs) provides a code of molecular identity and individuality to neurons, which plays a major role in the establishment of specific synaptic connectivity and formation of neuronal circuits. Particular attention has been directed to the Pcdh-γ family, for which experimental evidence derived from Pcdh-γ-deficient mice shows that they are involved in dendrite self-avoidance, synapse development, dendritic arborization, spine maturation, and prevention of apoptosis of some neurons. Moreover, a triple-mutant mouse deficient in the three C-type members of the Pcdh-γ family (Pcdh-γC3, Pcdh-γC4, and Pcdh-γC5) shows a phenotype similar to the mouse deficient in whole Pcdh-γ family, indicating that the latter is largely due to the absence of C-type Pcdh-γs. The role of each individual C-type Pcdh-γ is not known. We have developed a specific antibody to Pcdh-γC4 to reveal the expression of this protein in the rat brain. The results show that although Pcdh-γC4 is expressed at higher levels in the embryo and earlier postnatal weeks, it is also expressed in the adult rat brain. Pcdh-γC4 is expressed in both neurons and astrocytes. In the adult brain, the regional distribution of Pcdh-γC4 immunoreactivity is similar to that of Pcdh-γC4 mRNA, being highest in the olfactory bulb, dentate gyrus, and cerebellum. Pcdh-γC4 forms puncta that are frequently apposed to glutamatergic and GABAergic synapses. They are also frequently associated with neuron-astrocyte contacts. The results provide new insights into the cell recognition function of Pcdh-γC4 in neurons and astrocytes.
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Affiliation(s)
- Celia P Miralles
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Michael J Taylor
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - John Bear
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Christopher D Fekete
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Shanu George
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Yanfang Li
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Bevan Bonhomme
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Angel L De Blas
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
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Chiou TT, Long P, Schumann-Gillett A, Kanamarlapudi V, Haas SA, Harvey K, O'Mara ML, De Blas AL, Kalscheuer VM, Harvey RJ. Mutation p.R356Q in the Collybistin Phosphoinositide Binding Site Is Associated With Mild Intellectual Disability. Front Mol Neurosci 2019; 12:60. [PMID: 30914922 PMCID: PMC6422930 DOI: 10.3389/fnmol.2019.00060] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/19/2019] [Indexed: 11/13/2022] Open
Abstract
The recruitment of inhibitory GABAA receptors to neuronal synapses requires a complex interplay between receptors, neuroligins, the scaffolding protein gephyrin and the GDP-GTP exchange factor collybistin (CB). Collybistin is regulated by protein-protein interactions at the N-terminal SH3 domain, which can bind neuroligins 2/4 and the GABAAR α2 subunit. Collybistin also harbors a RhoGEF domain which mediates interactions with gephyrin and catalyzes GDP-GTP exchange on Cdc42. Lastly, collybistin has a pleckstrin homology (PH) domain, which binds phosphoinositides, such as phosphatidylinositol 3-phosphate (PI3P/PtdIns3P) and phosphatidylinositol 4-monophosphate (PI4P/PtdIns4P). PI3P located in early/sorting endosomes has recently been shown to regulate the postsynaptic clustering of gephyrin and GABAA receptors and consequently the strength of inhibitory synapses in cultured hippocampal neurons. This process is disrupted by mutations in the collybistin gene (ARHGEF9), which cause X-linked intellectual disability (XLID) by a variety of mechanisms converging on disrupted gephyrin and GABAA receptor clustering at central synapses. Here we report a novel missense mutation (chrX:62875607C>T, p.R356Q) in ARHGEF9 that affects one of the two paired arginine residues in the PH domain that were predicted to be vital for binding phosphoinositides. Functional assays revealed that recombinant collybistin CB3SH3- R356Q was deficient in PI3P binding and was not able to translocate EGFP-gephyrin to submembrane microaggregates in an in vitro clustering assay. Expression of the PI3P-binding mutants CB3SH3- R356Q and CB3SH3- R356N/R357N in cultured hippocampal neurones revealed that the mutant proteins did not accumulate at inhibitory synapses, but instead resulted in a clear decrease in the overall number of synaptic gephyrin clusters compared to controls. Molecular dynamics simulations suggest that the p.R356Q substitution influences PI3P binding by altering the range of structural conformations adopted by collybistin. Taken together, these results suggest that the p.R356Q mutation in ARHGEF9 is the underlying cause of XLID in the probands, disrupting gephyrin clustering at inhibitory GABAergic synapses via loss of collybistin PH domain phosphoinositide binding.
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Affiliation(s)
- Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Philip Long
- Department of Pharmacology, UCL School of Pharmacy, London, United Kingdom
| | | | | | - Stefan A Haas
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Kirsten Harvey
- Department of Pharmacology, UCL School of Pharmacy, London, United Kingdom
| | - Megan L O'Mara
- Research School of Chemistry, The Australian National University, Canberra, ACT, Australia
| | - Angel L De Blas
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Vera M Kalscheuer
- Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Robert J Harvey
- School of Health and Sport Sciences, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,Sunshine Coast Health Institute, Birtinya, QLD, Australia
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10
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Groeneweg FL, Trattnig C, Kuhse J, Nawrotzki RA, Kirsch J. Gephyrin: a key regulatory protein of inhibitory synapses and beyond. Histochem Cell Biol 2018; 150:489-508. [DOI: 10.1007/s00418-018-1725-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2018] [Indexed: 12/26/2022]
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11
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Romine H, Rentschler KM, Smith K, Edwards A, Colvin C, Farizatto K, Pait MC, Butler D, Bahr BA. Potential Alzheimer's Disease Therapeutics Among Weak Cysteine Protease Inhibitors Exhibit Mechanistic Differences Regarding Extent of Cathepsin B Up-Regulation and Ability to Block Calpain. ACTA ACUST UNITED AC 2017; 13:38-59. [PMID: 29805718 DOI: 10.19044/esj.2017.c1p5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cysteine protease inhibitors have long been part of drug discovery programs for Alzheimer's disease (AD), traumatic brain injury (TBI), and other disorders. Select inhibitors reduce accumulating proteins and AD pathology in mouse models. One such compound, Z-Phe-Aladiazomethylketone (PADK), exhibits a very weak IC50 (9-11 μM) towards cathepsin B (CatB), but curiously PADK causes marked up-regulation of the Aβ-degrading CatB and improves spatial memory. Potential therapeutic and weak inhibitor E64d (14 μM IC50) also up-regulates CatB. PADK and E64d were compared regarding the blockage of calcium-induced cytoskeletal deterioration in brain samples, monitoring the 150-kDa spectrin breakdown product (SBDP) known to be produced by calpain. PADK had little to no effect on SBDP production at 10-100 μM. In contrast, E64d caused a dose-dependent decline in SBDP levels with an IC50 of 3-6 μM, closely matching its reported potency for inhibiting μ-calpain. Calpain also cleaves the cytoskeletal organizing protein gephyrin, producing 49-kDa (GnBDP49) and 18-kDa (GnBDP18) breakdown products. PADK had no apparent effect on calcium-induced gephyrin fragments whereas E64d blocked their production. E64d also protected the parent gephyrin in correspondence with reduced BDP levels. The findings of this study indicate that PADK's positive and selective effects on CatB are consistent with human studies showing exercise elevates CatB and such elevation correlates with improved memory. On the other hand, E64d exhibits both marginal CatB enhancement and potent calpain inhibition. This dual effect may be beneficial for treating AD. Alternatively, the potent action on calpain-related pathology may explain E64d's protection in AD and TBI models.
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Affiliation(s)
- Heather Romine
- University of North Carolina - Pembroke, Pembroke, North Carolina, USA
| | | | - Kaitlan Smith
- University of North Carolina - Pembroke, Pembroke, North Carolina, USA
| | - Ayanna Edwards
- University of North Carolina - Pembroke, Pembroke, North Carolina, USA
| | - Camille Colvin
- University of North Carolina - Pembroke, Pembroke, North Carolina, USA
| | - Karen Farizatto
- University of North Carolina - Pembroke, Pembroke, North Carolina, USA
| | - Morgan C Pait
- University of North Carolina - Pembroke, Pembroke, North Carolina, USA
| | - David Butler
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, USA
| | - Ben A Bahr
- William C. Friday Laboratory, University of North Carolina - Pembroke, North Carolina, USA
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Benign Effect of Extremely Low-Frequency Electromagnetic Field on Brain Plasticity Assessed by Nitric Oxide Metabolism during Poststroke Rehabilitation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:2181942. [PMID: 29138675 PMCID: PMC5613626 DOI: 10.1155/2017/2181942] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/02/2017] [Accepted: 08/14/2017] [Indexed: 12/17/2022]
Abstract
Nitric oxide (NO) is one of the most important signal molecules, involved in both physiological and pathological processes. As a neurotransmitter in the central nervous system, NO regulates cerebral blood flow, neurogenesis, and synaptic plasticity. The aim of our study was to investigate the effect of the extremely low-frequency electromagnetic field (ELF-EMF) on generation and metabolism of NO, as a neurotransmitter, in the rehabilitation of poststroke patients. Forty-eight patients were divided into two groups: ELF-EMF and non-ELF-EMF. Both groups underwent the same 4-week rehabilitation program. Additionally, the ELF-EMF group was exposed to an extremely low-frequency electromagnetic field of 40 Hz, 7 mT, for 15 min/day. Levels of 3-nitrotyrosine, nitrate/nitrite, and TNFα in plasma samples were measured, and NOS2 expression was determined in whole blood samples. Functional status was evaluated before and after a series of treatments, using the Activity Daily Living, Geriatric Depression Scale, and Mini-Mental State Examination. We observed that application of ELF-EMF significantly increased 3-nitrotyrosine and nitrate/nitrite levels, while expression of NOS2 was insignificantly decreased in both groups. The results also show that ELF-EMF treatments improved functional and mental status. We conclude that ELF-EMF therapy is capable of promoting recovery in poststroke patients.
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