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Wang J, Guo Y, He Y, Qin Y, Li X, Yang L, Liu K, Xiao L. Hepatic regulator of G protein signaling 14 ameliorates NAFLD through activating cAMP-AMPK signaling by targeting Giα1/3. Mol Metab 2024; 80:101882. [PMID: 38237897 PMCID: PMC10844864 DOI: 10.1016/j.molmet.2024.101882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 01/28/2024] Open
Abstract
OBJECTIVE Nonalcoholic fatty liver disease (NAFLD) is an emerging public health threat as the most common chronic liver disease worldwide. However, there remains no effective medication to improve NAFLD. G protein-coupled receptors (GPCRs) are the most frequently investigated drug targets family. The Regulator of G protein signaling 14 (RGS14), as an essential negative modulator of GPCR signaling, plays important regulatory roles in liver damage and inflammatory responses. However, the role of RGS14 in NAFLD remains largely unclear. METHODS AND RESULTS In this study, we found that RGS14 was decreased in hepatocytes in NAFLD individuals in a public database. We employed genetic engineering technique to explore the function of RGS14 in NAFLD. We demonstrated that RGS14 overexpression ameliorated lipid accumulation, inflammatory response and liver fibrosis in hepatocytes in vivo and in vitro. Whereas, hepatocyte specific Rgs14-knockout (Rgs14-HKO) exacerbated high fat high cholesterol diet (HFHC) induced NASH. Further molecular experiments demonstrated that RGS14 depended on GDI activity to attenuate HFHC-feeding NASH. More importantly, RGS14 interacted with Guanine nucleotide-binding protein (Gi) alpha 1 and 3 (Giα1/3, gene named GNAI1/3), promoting the generation of cAMP and then activating the subsequent AMPK pathways. GNAI1/3 knockdown abolished the protective role of RGS14, indicating that RGS14 binding to Giα1/3 was required for prevention against hepatic steatosis. CONCLUSIONS RGS14 plays a protective role in the progression of NAFLD. RGS14-Giα1/3 interaction accelerated the production of cAMP and then activated cAMP-AMPK signaling. Targeting RGS14 or modulating the RGS14-Giα1/3 interaction may be a potential strategy for the treatment of NAFLD in the future.
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Affiliation(s)
- Junyong Wang
- Center for Basic Medical Research, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Yaping Guo
- Department of Pathophysiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Yunduan He
- The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou, Henan 450008, China
| | - Yifan Qin
- Center for Basic Medical Research, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Xiuling Li
- Department of Gastroenterology, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, Henan 450004, China
| | - Ling Yang
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Kangdong Liu
- Center for Basic Medical Research, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450052, China.
| | - Li Xiao
- Department of Gastroenterology, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, Henan 450004, China.
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Samadi M, Hales CA, Lustberg DJ, Farris S, Ross MR, Zhao M, Hepler JR, Harbin NH, Robinson ESJ, Banks PJ, Bashir ZI, Dudek SM. Mechanisms of mGluR-dependent plasticity in hippocampal area CA2. Hippocampus 2023; 33:730-744. [PMID: 36971428 PMCID: PMC10213158 DOI: 10.1002/hipo.23529] [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: 02/18/2023] [Revised: 03/04/2023] [Accepted: 03/08/2023] [Indexed: 03/29/2023]
Abstract
Pyramidal cells in hippocampal area CA2 have synaptic properties that are distinct from the other CA subregions. Notably, this includes a lack of typical long-term potentiation of stratum radiatum synapses. CA2 neurons express high levels of several known and potential regulators of metabotropic glutamate receptor (mGluR)-dependent signaling including Striatal-Enriched Tyrosine Phosphatase (STEP) and several Regulator of G-protein Signaling (RGS) proteins, yet the functions of these proteins in regulating mGluR-dependent synaptic plasticity in CA2 are completely unknown. Thus, the aim of this study was to examine mGluR-dependent synaptic depression and to determine whether STEP and the RGS proteins RGS4 and RGS14 are involved. Using whole cell voltage-clamp recordings from mouse pyramidal cells, we found that mGluR agonist-induced long-term depression (mGluR-LTD) is more pronounced in CA2 compared with that observed in CA1. This mGluR-LTD in CA2 was found to be protein synthesis and STEP dependent, suggesting that CA2 mGluR-LTD shares mechanistic processes with those seen in CA1, but in addition, RGS14, but not RGS4, was essential for mGluR-LTD in CA2. In addition, we found that exogenous application of STEP could rescue mGluR-LTD in RGS14 KO slices. Supporting a role for CA2 synaptic plasticity in social cognition, we found that RGS14 KO mice had impaired social recognition memory as assessed in a social discrimination task. These results highlight possible roles for mGluRs, RGS14, and STEP in CA2-dependent behaviors, perhaps by biasing the dominant form of synaptic plasticity away from LTP and toward LTD in CA2.
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Affiliation(s)
- Mahsa Samadi
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
- Present address:
Faculty Education Office, Faculty of Medicine, Imperial College London, Hammersmith Campus, Wolfson Education CentreLondonUKW12 0NN
| | - Claire A. Hales
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
- Present address:
Department of Psychology, Djavad Mowafaghian Centre for Brain HealthUniversity of British Columbia2215, Wesbrook MallVancouverBritish ColumbiaV6T 1Z3Canada
| | - Daniel J. Lustberg
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
- Present address:
Mouse Pharmacology GroupPsychogenics Inc215 College RoadParamusNew Jersey07652USA
| | - Shannon Farris
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
- Present address:
Fralin Biomedical Research Institute at Virginia TechRoanokeVirginia24014USA
| | - Madeleine R. Ross
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
| | - Meilan Zhao
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
| | - John R. Hepler
- Department of Pharmacology and Chemical BiologyEmory University School of Medicine100 Woodruff CircleAtlantaGeorgia30322USA
| | - Nicholas H. Harbin
- Department of Pharmacology and Chemical BiologyEmory University School of Medicine100 Woodruff CircleAtlantaGeorgia30322USA
| | - Emma S. J. Robinson
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
| | - Paul J. Banks
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
| | - Zafar I. Bashir
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
| | - Serena M. Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
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3
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Montañez-Miranda C, Perszyk RE, Harbin NH, Okalova J, Ramineni S, Traynelis SF, Hepler JR. Functional Assessment of Cancer-Linked Mutations in Sensitive Regions of Regulators of G Protein Signaling Predicted by Three-Dimensional Missense Tolerance Ratio Analysis. Mol Pharmacol 2023; 103:21-37. [PMID: 36384958 PMCID: PMC10955721 DOI: 10.1124/molpharm.122.000614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/04/2022] [Accepted: 10/18/2022] [Indexed: 11/18/2022] Open
Abstract
Regulators of G protein signaling (RGS) proteins modulate G protein-coupled receptor (GPCR) signaling by acting as negative regulators of G proteins. Genetic variants in RGS proteins are associated with many diseases, including cancers, although the impact of these mutations on protein function is uncertain. Here we analyze the RGS domains of 15 RGS protein family members using a novel bioinformatic tool that measures the missense tolerance ratio (MTR) using a three-dimensional (3D) structure (3DMTR). Subsequent permutation analysis can define the protein regions that are most significantly intolerant (P < 0.05) in each dataset. We further focused on RGS14, RGS10, and RGS4. RGS14 exhibited seven significantly tolerant and seven significantly intolerant residues, RGS10 had six intolerant residues, and RGS4 had eight tolerant and six intolerant residues. Intolerant and tolerant-control residues that overlap with pathogenic cancer mutations reported in the COSMIC cancer database were selected to define the functional phenotype. Using complimentary cellular and biochemical approaches, proteins were tested for effects on GPCR-Gα activation, Gα binding properties, and downstream cAMP levels. Identified intolerant residues with reported cancer-linked mutations RGS14-R173C/H and RGS4-K125Q/E126K, and tolerant RGS14-S127P and RGS10-S64T resulted in a loss-of-function phenotype in GPCR-G protein signaling activity. In downstream cAMP measurement, tolerant RGS14-D137Y and RGS10-S64T and intolerant RGS10-K89M resulted in change of function phenotypes. These findings show that 3DMTR identified intolerant residues that overlap with cancer-linked mutations cause phenotypic changes that negatively impact GPCR-G protein signaling and suggests that 3DMTR is a potentially useful bioinformatics tool for predicting functionally important protein residues. SIGNIFICANCE STATEMENT: Human genetic variant/mutation information has expanded rapidly in recent years, including cancer-linked mutations in regulator of G protein signaling (RGS) proteins. However, experimental testing of the impact of this vast catalogue of mutations on protein function is not feasible. We used the novel bioinformatics tool three-dimensional missense tolerance ratio (3DMTR) to define regions of genetic intolerance in RGS proteins and prioritize which cancer-linked mutants to test. We found that 3DMTR more accurately classifies loss-of-function mutations in RGS proteins than other databases thereby offering a valuable new research tool.
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Affiliation(s)
- Carolina Montañez-Miranda
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - Riley E Perszyk
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - Nicholas H Harbin
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - Jennifer Okalova
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - Suneela Ramineni
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - Stephen F Traynelis
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - John R Hepler
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
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4
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ECIROGLU H, ŞENER EF, ÖZTOP DB, ÖZMEN S, KAAN D, ÖZKUL Y. Otizm Spektrum Bozukluğu Olan Hastalarda Öğrenme ve Hafıza Bozukluklarının NEURL1 ve RGS14 Genleri ile İlişkisi. ACTA MEDICA ALANYA 2022. [DOI: 10.30565/medalanya.1136820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aim: We aimed to evaluate the relationship between learning-memory difficulties and NEURL1 and RGS14 genes in patients with autism spectrum disorders (ASD).
Method: Forty children with ASD (20 ASD, 20 high functioning autism (HFA)) and 20 healthy controls were enrolled in this study. NEURL1 and RGS14 gene expressions in the blood samples of volunteers were assessed by quantitative Real-Time PCR (qRT-PCR). The clinical and demographical findings in patients were determined and examined relation with the gene expressions.
Results: According to our findings, NEURL1 gene expression was decreased in both patient groups compared to the control (p0.05). A statistically significant correlation was found between learning and memory difficulties and RGS14 gene expression in HFA patients (p = 0.045). There was a positive correlation between between NEURL1 and RGS14 gene expressions of ASD patients (p=0.032, r=0,59).
Conclusion: According to this study, NEURL1 gene may be proposed as a candidate gene for ASD. Nonetheless, we recommend that both genes be studied with more patients and preferably with brain tissues. These genes were evaluated for the first time in a clinical study on autism, and we believe that they will contribute to the literature in this respect.
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Affiliation(s)
- Hamiyet ECIROGLU
- ALANYA ALAADDIN KEYKUBAT UNIVERSITY, HEALTH SERVICES VOCATIONAL SCHOOL
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5
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RGS14 Regulation of Post-Synaptic Signaling and Spine Plasticity in Brain. Int J Mol Sci 2021; 22:ijms22136823. [PMID: 34201943 PMCID: PMC8268017 DOI: 10.3390/ijms22136823] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/12/2021] [Accepted: 06/14/2021] [Indexed: 02/06/2023] Open
Abstract
The regulator of G-protein signaling 14 (RGS14) is a multifunctional signaling protein that regulates post synaptic plasticity in neurons. RGS14 is expressed in the brain regions essential for learning, memory, emotion, and stimulus-induced behaviors, including the basal ganglia, limbic system, and cortex. Behaviorally, RGS14 regulates spatial and object memory, female-specific responses to cued fear conditioning, and environmental- and psychostimulant-induced locomotion. At the cellular level, RGS14 acts as a scaffolding protein that integrates G protein, Ras/ERK, and calcium/calmodulin signaling pathways essential for spine plasticity and cell signaling, allowing RGS14 to naturally suppress long-term potentiation (LTP) and structural plasticity in hippocampal area CA2 pyramidal cells. Recent proteomics findings indicate that RGS14 also engages the actomyosin system in the brain, perhaps to impact spine morphogenesis. Of note, RGS14 is also a nucleocytoplasmic shuttling protein, where its role in the nucleus remains uncertain. Balanced nuclear import/export and dendritic spine localization are likely essential for RGS14 neuronal functions as a regulator of synaptic plasticity. Supporting this idea, human genetic variants disrupting RGS14 localization also disrupt RGS14’s effects on plasticity. This review will focus on the known and unexplored roles of RGS14 in cell signaling, physiology, disease and behavior.
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6
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Robert V, Therreau L, Davatolhagh MF, Bernardo-Garcia FJ, Clements KN, Chevaleyre V, Piskorowski RA. The mechanisms shaping CA2 pyramidal neuron action potential bursting induced by muscarinic acetylcholine receptor activation. J Gen Physiol 2021; 152:133812. [PMID: 32069351 PMCID: PMC7141590 DOI: 10.1085/jgp.201912462] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 12/18/2019] [Accepted: 01/13/2020] [Indexed: 01/04/2023] Open
Abstract
Recent studies have revealed that hippocampal area CA2 plays an important role in hippocampal network function. Disruption of this region has been implicated in neuropsychiatric disorders. It is well appreciated that cholinergic input to the hippocampus plays an important role in learning and memory. While the effect of elevated cholinergic tone has been well studied in areas CA1 and CA3, it remains unclear how changes in cholinergic tone impact synaptic transmission and the intrinsic properties of neurons in area CA2. In this study, we applied the cholinergic agonist carbachol and performed on-cell, whole-cell, and extracellular recordings in area CA2. We observed that under conditions of high cholinergic tone, CA2 pyramidal neurons depolarized and rhythmically fired bursts of action potentials. This depolarization depended on the activation of M1 and M3 cholinergic receptors. Furthermore, we examined how the intrinsic properties and action-potential firing were altered in CA2 pyramidal neurons treated with 10 µM carbachol. While this intrinsic burst firing persisted in the absence of synaptic transmission, bursts were shaped by synaptic inputs in the intact network. We found that both excitatory and inhibitory synaptic transmission were reduced upon carbachol treatment. Finally, we examined the contribution of different channels to the cholinergic-induced changes in neuronal properties. We found that a conductance from Kv7 channels partially contributed to carbachol-induced changes in resting membrane potential and membrane resistance. We also found that D-type potassium currents contributed to controlling several properties of the bursts, including firing rate and burst kinetics. Furthermore, we determined that T-type calcium channels and small conductance calcium-activated potassium channels play a role in regulating bursting activity.
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Affiliation(s)
- Vincent Robert
- Université Paris Descartes, Inserm UMR1266, Institute of Psychiatry and Neuroscience of Paris, Team Synaptic Plasticity and Neural Networks, Paris, France
| | - Ludivine Therreau
- Université Paris Descartes, Inserm UMR1266, Institute of Psychiatry and Neuroscience of Paris, Team Synaptic Plasticity and Neural Networks, Paris, France
| | - M Felicia Davatolhagh
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - F Javier Bernardo-Garcia
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA
| | | | - Vivien Chevaleyre
- Université Paris Descartes, Inserm UMR1266, Institute of Psychiatry and Neuroscience of Paris, Team Synaptic Plasticity and Neural Networks, Paris, France
| | - Rebecca A Piskorowski
- Université Paris Descartes, Inserm UMR1266, Institute of Psychiatry and Neuroscience of Paris, Team Synaptic Plasticity and Neural Networks, Paris, France
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7
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Squires KE, Gerber KJ, Tillman MC, Lustberg DJ, Montañez-Miranda C, Zhao M, Ramineni S, Scharer CD, Saha RN, Shu FJ, Schroeder JP, Ortlund EA, Weinshenker D, Dudek SM, Hepler JR. Human genetic variants disrupt RGS14 nuclear shuttling and regulation of LTP in hippocampal neurons. J Biol Chem 2021; 296:100024. [PMID: 33410399 PMCID: PMC7949046 DOI: 10.1074/jbc.ra120.016009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/26/2020] [Accepted: 11/04/2020] [Indexed: 12/13/2022] Open
Abstract
The human genome contains vast genetic diversity as naturally occurring coding variants, yet the impact of these variants on protein function and physiology is poorly understood. RGS14 is a multifunctional signaling protein that suppresses synaptic plasticity in dendritic spines of hippocampal neurons. RGS14 also is a nucleocytoplasmic shuttling protein, suggesting that balanced nuclear import/export and dendritic spine localization are essential for RGS14 functions. We identified genetic variants L505R (LR) and R507Q (RQ) located within the nuclear export sequence (NES) of human RGS14. Here we report that RGS14 encoding LR or RQ profoundly impacts protein functions in hippocampal neurons. RGS14 membrane localization is regulated by binding Gαi-GDP, whereas RGS14 nuclear export is regulated by Exportin 1 (XPO1). Remarkably, LR and RQ variants disrupt RGS14 binding to Gαi1-GDP and XPO1, nucleocytoplasmic equilibrium, and capacity to inhibit long-term potentiation (LTP). Variant LR accumulates irreversibly in the nucleus, preventing RGS14 binding to Gαi1, localization to dendritic spines, and inhibitory actions on LTP induction, while variant RQ exhibits a mixed phenotype. When introduced into mice by CRISPR/Cas9, RGS14-LR protein expression was detected predominantly in the nuclei of neurons within hippocampus, central amygdala, piriform cortex, and striatum, brain regions associated with learning and synaptic plasticity. Whereas mice completely lacking RGS14 exhibit enhanced spatial learning, mice carrying variant LR exhibit normal spatial learning, suggesting that RGS14 may have distinct functions in the nucleus independent from those in dendrites and spines. These findings show that naturally occurring genetic variants can profoundly alter normal protein function, impacting physiology in unexpected ways.
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Affiliation(s)
- Katherine E Squires
- Department of Pharmacology and Chemical Biology, Emory University, Atlanta Georgia, USA
| | - Kyle J Gerber
- Department of Pharmacology and Chemical Biology, Emory University, Atlanta Georgia, USA
| | | | - Daniel J Lustberg
- Department of Human Genetics, Emory University, Atlanta Georgia, USA
| | | | - Meilan Zhao
- National Institute of Environmental Health Sciences, Research Triangle Park, Raleigh North Carolina, USA
| | - Suneela Ramineni
- Department of Pharmacology and Chemical Biology, Emory University, Atlanta Georgia, USA
| | | | - Ramendra N Saha
- Department of Molecular & Cell Biology, University of California-Merced, Merced California, USA
| | - Feng-Jue Shu
- Department of Pharmacology and Chemical Biology, Emory University, Atlanta Georgia, USA
| | - Jason P Schroeder
- Department of Human Genetics, Emory University, Atlanta Georgia, USA
| | - Eric A Ortlund
- Department of Biochemistry, Emory University, Atlanta Georgia, USA
| | - David Weinshenker
- Department of Human Genetics, Emory University, Atlanta Georgia, USA
| | - Serena M Dudek
- National Institute of Environmental Health Sciences, Research Triangle Park, Raleigh North Carolina, USA
| | - John R Hepler
- Department of Pharmacology and Chemical Biology, Emory University, Atlanta Georgia, USA.
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8
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Evans PR, Gerber KJ, Dammer EB, Duong DM, Goswami D, Lustberg DJ, Zou J, Yang JJ, Dudek SM, Griffin PR, Seyfried NT, Hepler JR. Interactome Analysis Reveals Regulator of G Protein Signaling 14 (RGS14) is a Novel Calcium/Calmodulin (Ca 2+/CaM) and CaM Kinase II (CaMKII) Binding Partner. J Proteome Res 2018. [PMID: 29518331 DOI: 10.1021/acs.jproteome.8b00027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Regulator of G Protein Signaling 14 (RGS14) is a complex scaffolding protein that integrates G protein and MAPK signaling pathways. In the adult mouse brain, RGS14 is predominantly expressed in hippocampal CA2 neurons where it naturally inhibits synaptic plasticity and hippocampus-dependent learning and memory. However, the signaling proteins that RGS14 natively engages to regulate plasticity are unknown. Here, we show that RGS14 exists in a high-molecular-weight protein complex in brain. To identify RGS14 neuronal interacting partners, endogenous RGS14 immunoprecipitated from mouse brain was subjected to mass spectrometry and proteomic analysis. We find that RGS14 interacts with key postsynaptic proteins that regulate plasticity. Gene ontology analysis reveals the most enriched RGS14 interactors have functional roles in actin-binding, calmodulin(CaM)-binding, and CaM-dependent protein kinase (CaMK) activity. We validate these findings using biochemical assays that identify interactions with two previously unknown binding partners. We report that RGS14 directly interacts with Ca2+/CaM and is phosphorylated by CaMKII in vitro. Lastly, we detect that RGS14 associates with CaMKII and CaM in hippocampal CA2 neurons. Taken together, these findings demonstrate that RGS14 is a novel CaM effector and CaMKII phosphorylation substrate thereby providing new insight into mechanisms by which RGS14 controls plasticity in CA2 neurons.
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Affiliation(s)
| | | | | | | | - Devrishi Goswami
- Department of Molecular Medicine , The Scripps Research Institute , Jupiter , Florida 33458 , United States
| | - Daniel J Lustberg
- Neurobiology Laboratory , National Institute of Environmental Health Sciences, National Institutes of Health , Research Triangle Park , North Carolina 27709 , United States
| | - Juan Zou
- Department of Chemistry, Center for Diagnostics and Therapeutics , Georgia State University , Atlanta , Georgia 30303 , United States
| | - Jenny J Yang
- Department of Chemistry, Center for Diagnostics and Therapeutics , Georgia State University , Atlanta , Georgia 30303 , United States
| | - Serena M Dudek
- Neurobiology Laboratory , National Institute of Environmental Health Sciences, National Institutes of Health , Research Triangle Park , North Carolina 27709 , United States
| | - Patrick R Griffin
- Department of Molecular Medicine , The Scripps Research Institute , Jupiter , Florida 33458 , United States
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9
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Hippocampal area CA2: properties and contribution to hippocampal function. Cell Tissue Res 2018; 373:525-540. [PMID: 29335778 DOI: 10.1007/s00441-017-2769-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/07/2017] [Indexed: 12/30/2022]
Abstract
This review focuses on area CA2 of the hippocampus, as recent results have revealed the unique properties and surprising role of this region in encoding social, temporal and contextual aspects of memory. Originally identified and described by Lorente de No, in 1934, this region of the hippocampus has unique intra-and extra-hippocampal connectivity, sending and receiving input to septal and hypothalamic regions. Recent in vivo studies have indicated that CA2 pyramidal neurons encode spatial information during immobility and play an important role in the generation of sharp-wave ripples. Furthermore, CA2 neurons act to control overall excitability in the hippocampal network and have been found to be consistently altered in psychiatric diseases, indicating that normal function of this region is necessary for normal cognition. With its unique role, area CA2 has a unique molecular profile, interneuron density and composition. Furthermore, this region has an unusual manifestation of synaptic plasticity that does not occur post-synaptically at pyramidal neuron dendrities but through the local network of inhibitory neurons. While much progress has recently been made in understanding the large contribution of area CA2 to social memory formation, much still needs to be learned.
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10
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An epigenome-wide methylation study of healthy individuals with or without depressive symptoms. J Hum Genet 2018; 63:319-326. [PMID: 29305581 DOI: 10.1038/s10038-017-0382-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 09/29/2017] [Accepted: 10/11/2017] [Indexed: 12/23/2022]
Abstract
Major depressive disorder is a common psychiatric disorder that is thought to be triggered by both genetic and environmental factors. Depressive symptoms are an important public health problem and contribute to vulnerability to major depression. Although a substantial number of genetic and epigenetic studies have been performed to date, the detailed etiology of depression remains unclear and there are no validated biomarkers. DNA methylation is one of the major epigenetic modifications that play diverse roles in the etiology of complex diseases. In this study, we performed an epigenome-wide association study (EWAS) of DNA methylation on subjects with (N = 20) or without (N = 27) depressive symptoms in order to examine whether different levels of DNA methylation were associated with depressive tendencies. Employing methylation-array technology, a total of 363,887 methylation sites across the genomes were investigated and several candidate CpG sites associated with depressive symptoms were identified, especially annotated to genes linked to a G-protein coupled receptor protein signaling pathway. These data provide a strong impetus for validation studies using a larger cohort and support the possibility that G-protein coupled receptor protein signaling pathways are involved in the pathogenesis of depression.
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11
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Regulator of G protein signaling 14 (RGS14) is expressed pre- and postsynaptically in neurons of hippocampus, basal ganglia, and amygdala of monkey and human brain. Brain Struct Funct 2017; 223:233-253. [PMID: 28776200 DOI: 10.1007/s00429-017-1487-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 07/26/2017] [Indexed: 12/18/2022]
Abstract
Regulator of G protein signaling 14 (RGS14) is a multifunctional signaling protein primarily expressed in mouse pyramidal neurons of hippocampal area CA2 where it regulates synaptic plasticity important for learning and memory. However, very little is known about RGS14 protein expression in the primate brain. Here, we validate the specificity of a new polyclonal RGS14 antibody that recognizes not only full-length RGS14 protein in primate, but also lower molecular weight forms of RGS14 protein matching previously predicted human splice variants. These putative RGS14 variants along with full-length RGS14 are expressed in the primate striatum. By contrast, only full-length RGS14 is expressed in hippocampus, and shorter variants are completely absent in rodent brain. We report that RGS14 protein immunoreactivity is found both pre- and postsynaptically in multiple neuron populations throughout hippocampal area CA1 and CA2, caudate nucleus, putamen, globus pallidus, substantia nigra, and amygdala in adult rhesus monkeys. A similar cellular expression pattern of RGS14 in the monkey striatum and hippocampus was further confirmed in humans. Our electron microscopy data show for the first time that RGS14 immunostaining localizes within nuclei of striatal neurons in monkeys. Taken together, these findings suggest new pre- and postsynaptic regulatory functions of RGS14 and RGS14 variants, specific to the primate brain, and provide evidence for unconventional roles of RGS14 in the nuclei of striatal neurons potentially important for human neurophysiology and disease.
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Alqinyah M, Maganti N, Ali MW, Yadav R, Gao M, Cacan E, Weng HR, Greer SF, Hooks SB. Regulator of G Protein Signaling 10 (Rgs10) Expression Is Transcriptionally Silenced in Activated Microglia by Histone Deacetylase Activity. Mol Pharmacol 2016; 91:197-207. [PMID: 28031332 DOI: 10.1124/mol.116.106963] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 12/12/2016] [Indexed: 02/06/2023] Open
Abstract
RGS10 has emerged as a key regulator of proinflammatory cytokine production in microglia, functioning as an important neuroprotective factor. Although RGS10 is normally expressed in microglia at high levels, expression is silenced in vitro following activation of TLR4 receptor. Given the ability of RGS10 to regulate inflammatory signaling, dynamic regulation of RGS10 levels in microglia may be an important mechanism to tune inflammatory responses. The goals of the current study were to confirm that RGS10 is suppressed in an in vivo inflammatory model of microglial activation and to determine the mechanism for activation-dependent silencing of Rgs10 expression in microglia. We demonstrate that endogenous RGS10 is present in spinal cord microglia, and RGS10 protein levels are suppressed in the spinal cord in a nerve injury-induced neuropathic pain mouse model. We show that the histone deacetylase (HDAC) enzyme inhibitor trichostatin A blocks the ability of lipopolysaccharide (LPS) to suppress Rgs10 transcription in BV-2 and primary microglia, demonstrating that HDAC enzymes are required for LPS silencing of Rgs10 Furthermore, we used chromatin immunoprecipitation to demonstrate that H3 histones at the Rgs10 proximal promoter are deacetylated in BV-2 microglia following LPS activation, and HDAC1 association at the Rgs10 promoter is enhanced following LPS stimulation. Finally, we have shown that sphingosine 1-phosphate, an endogenous microglial signaling mediator that inhibits HDAC activity, enhances basal Rgs10 expression in BV-2 microglia, suggesting that Rgs10 expression is dynamically regulated in microglia in response to multiple signals.
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Affiliation(s)
- Mohammed Alqinyah
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia (M.A., M.W.A., R.Y., M.G., H.-R.W., S.B.H.); and Department of Biology, Georgia State University, Atlanta, Georgia (N.M., E.C., S.F.G.)
| | - Nagini Maganti
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia (M.A., M.W.A., R.Y., M.G., H.-R.W., S.B.H.); and Department of Biology, Georgia State University, Atlanta, Georgia (N.M., E.C., S.F.G.)
| | - Mourad W Ali
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia (M.A., M.W.A., R.Y., M.G., H.-R.W., S.B.H.); and Department of Biology, Georgia State University, Atlanta, Georgia (N.M., E.C., S.F.G.)
| | - Ruchi Yadav
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia (M.A., M.W.A., R.Y., M.G., H.-R.W., S.B.H.); and Department of Biology, Georgia State University, Atlanta, Georgia (N.M., E.C., S.F.G.)
| | - Mei Gao
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia (M.A., M.W.A., R.Y., M.G., H.-R.W., S.B.H.); and Department of Biology, Georgia State University, Atlanta, Georgia (N.M., E.C., S.F.G.)
| | - Ercan Cacan
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia (M.A., M.W.A., R.Y., M.G., H.-R.W., S.B.H.); and Department of Biology, Georgia State University, Atlanta, Georgia (N.M., E.C., S.F.G.)
| | - Han-Rong Weng
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia (M.A., M.W.A., R.Y., M.G., H.-R.W., S.B.H.); and Department of Biology, Georgia State University, Atlanta, Georgia (N.M., E.C., S.F.G.)
| | - Susanna F Greer
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia (M.A., M.W.A., R.Y., M.G., H.-R.W., S.B.H.); and Department of Biology, Georgia State University, Atlanta, Georgia (N.M., E.C., S.F.G.)
| | - Shelley B Hooks
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia (M.A., M.W.A., R.Y., M.G., H.-R.W., S.B.H.); and Department of Biology, Georgia State University, Atlanta, Georgia (N.M., E.C., S.F.G.)
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Regulator of G protein signalling 14 attenuates cardiac remodelling through the MEK-ERK1/2 signalling pathway. Basic Res Cardiol 2016; 111:47. [PMID: 27298141 PMCID: PMC4906057 DOI: 10.1007/s00395-016-0566-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 06/01/2016] [Indexed: 12/02/2022]
Abstract
In the past 10 years, several publications have highlighted the role of the regulator of G protein signalling (RGS) family in multiple diseases, including cardiovascular diseases. As one of the multifunctional family members, RGS14 is involved in various biological processes, such as synaptic plasticity, cell division, and phagocytosis. However, the role of RGS14 in cardiovascular diseases remains unclear. In the present study, we used a genetic approach to examine the role of RGS14 in pathological cardiac remodelling in vivo and in vitro. We observed that RGS14 was down-regulated in human failing hearts, murine hypertrophic hearts, and isolated hypertrophic cardiomyocytes. Moreover, the extent of aortic banding-induced cardiac hypertrophy and fibrosis was exacerbated in RGS14 knockout mice, whereas RGS14 transgenic mice exhibited a significantly alleviated response to pressure overload. Furthermore, research of the underlying mechanism revealed that the RGS14-dependent rescue of cardiac remodelling was attributed to the abrogation of mitogen-activated protein kinase (MEK)–extracellular signal-regulated protein kinase (ERK) 1/2 signalling. The results showed that constitutive activation of MEK1 nullified the cardiac protection in RGS14 transgenic mice, and inhibition of MEK–ERK1/2 by U0126 reversed RGS14 deletion-related hypertrophic aggravation. These results demonstrated that RGS14 attenuated the development of cardiac remodelling through MEK–ERK1/2 signalling. RGS14 exhibited great potential as a target for the treatment of pathological cardiac remodelling.
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Abstract
Hippocampal area CA2 has several features that distinguish it from CA1 and CA3, including a unique gene expression profile, failure to display long-term potentiation and relative resistance to cell death. A recent increase in interest in the CA2 region, combined with the development of new methods to define and manipulate its neurons, has led to some exciting new discoveries on the properties of CA2 neurons and their role in behaviour. Here, we review these findings and call attention to the idea that the definition of area CA2 ought to be revised in light of gene expression data.
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He F, Jones JM, Figueroa-Romero C, Zhang D, Feldman EL, Goutman SA, Meisler MH, Callaghan BC, Todd PK. Screening for novel hexanucleotide repeat expansions at ALS- and FTD-associated loci. NEUROLOGY-GENETICS 2016; 2:e71. [PMID: 27274540 PMCID: PMC4865132 DOI: 10.1212/nxg.0000000000000071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/01/2016] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To determine whether GGGGCC (G4C2) repeat expansions at loci other than C9orf72 serve as common causes of amyotrophic lateral sclerosis (ALS). METHODS We assessed G4C2 repeat number in 28 genes near known ALS and frontotemporal dementia (FTD) loci by repeat-primed PCR coupled with fluorescent fragment analysis in 199 patients with ALS (17 familial, 182 sporadic) and 136 healthy controls. We also obtained blood from patients with ALS4 for evaluation of repeats surrounding the SETX gene locus. C9orf72 expansions were evaluated in parallel. RESULTS Expansions of G4C2 repeats in C9orf72 explained 8.8% of sporadic and 47% of familial ALS cases analyzed. Repeat variance was observed at one other locus, RGS14, but no large expansions were observed, and repeat sizes were not different between cases and controls. No G4C2 repeat expansions were identified at other ALS or FTD risk loci or in ALS4 cases. CONCLUSIONS G4C2 expansions near known ALS and FTD loci other than C9orf72 are not a common cause of ALS.
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Affiliation(s)
- Fang He
- Department of Neurology (F.H., C.F.-R., B.C.C., E.L.F., S.A.G., P.K.T.) and Department of Human Genetics (J.M.J., M.H.M.), University of Michigan, Ann Arbor; Veteran Association Health System (B.C.C., P.K.T.), Ann Arbor; and National Center for Biotechnology Information (D.Z.), National Institutes of Health, Bethesda, MD
| | - Julie M Jones
- Department of Neurology (F.H., C.F.-R., B.C.C., E.L.F., S.A.G., P.K.T.) and Department of Human Genetics (J.M.J., M.H.M.), University of Michigan, Ann Arbor; Veteran Association Health System (B.C.C., P.K.T.), Ann Arbor; and National Center for Biotechnology Information (D.Z.), National Institutes of Health, Bethesda, MD
| | - Claudia Figueroa-Romero
- Department of Neurology (F.H., C.F.-R., B.C.C., E.L.F., S.A.G., P.K.T.) and Department of Human Genetics (J.M.J., M.H.M.), University of Michigan, Ann Arbor; Veteran Association Health System (B.C.C., P.K.T.), Ann Arbor; and National Center for Biotechnology Information (D.Z.), National Institutes of Health, Bethesda, MD
| | - Dapeng Zhang
- Department of Neurology (F.H., C.F.-R., B.C.C., E.L.F., S.A.G., P.K.T.) and Department of Human Genetics (J.M.J., M.H.M.), University of Michigan, Ann Arbor; Veteran Association Health System (B.C.C., P.K.T.), Ann Arbor; and National Center for Biotechnology Information (D.Z.), National Institutes of Health, Bethesda, MD
| | - Eva L Feldman
- Department of Neurology (F.H., C.F.-R., B.C.C., E.L.F., S.A.G., P.K.T.) and Department of Human Genetics (J.M.J., M.H.M.), University of Michigan, Ann Arbor; Veteran Association Health System (B.C.C., P.K.T.), Ann Arbor; and National Center for Biotechnology Information (D.Z.), National Institutes of Health, Bethesda, MD
| | - Stephen A Goutman
- Department of Neurology (F.H., C.F.-R., B.C.C., E.L.F., S.A.G., P.K.T.) and Department of Human Genetics (J.M.J., M.H.M.), University of Michigan, Ann Arbor; Veteran Association Health System (B.C.C., P.K.T.), Ann Arbor; and National Center for Biotechnology Information (D.Z.), National Institutes of Health, Bethesda, MD
| | - Miriam H Meisler
- Department of Neurology (F.H., C.F.-R., B.C.C., E.L.F., S.A.G., P.K.T.) and Department of Human Genetics (J.M.J., M.H.M.), University of Michigan, Ann Arbor; Veteran Association Health System (B.C.C., P.K.T.), Ann Arbor; and National Center for Biotechnology Information (D.Z.), National Institutes of Health, Bethesda, MD
| | - Brian C Callaghan
- Department of Neurology (F.H., C.F.-R., B.C.C., E.L.F., S.A.G., P.K.T.) and Department of Human Genetics (J.M.J., M.H.M.), University of Michigan, Ann Arbor; Veteran Association Health System (B.C.C., P.K.T.), Ann Arbor; and National Center for Biotechnology Information (D.Z.), National Institutes of Health, Bethesda, MD
| | - Peter K Todd
- Department of Neurology (F.H., C.F.-R., B.C.C., E.L.F., S.A.G., P.K.T.) and Department of Human Genetics (J.M.J., M.H.M.), University of Michigan, Ann Arbor; Veteran Association Health System (B.C.C., P.K.T.), Ann Arbor; and National Center for Biotechnology Information (D.Z.), National Institutes of Health, Bethesda, MD
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Sosa M, Gillespie AK, Frank LM. Neural Activity Patterns Underlying Spatial Coding in the Hippocampus. Curr Top Behav Neurosci 2016; 37:43-100. [PMID: 27885550 DOI: 10.1007/7854_2016_462] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The hippocampus is well known as a central site for memory processing-critical for storing and later retrieving the experiences events of daily life so they can be used to shape future behavior. Much of what we know about the physiology underlying hippocampal function comes from spatial navigation studies in rodents, which have allowed great strides in understanding how the hippocampus represents experience at the cellular level. However, it remains a challenge to reconcile our knowledge of spatial encoding in the hippocampus with its demonstrated role in memory-dependent tasks in both humans and other animals. Moreover, our understanding of how networks of neurons coordinate their activity within and across hippocampal subregions to enable the encoding, consolidation, and retrieval of memories is incomplete. In this chapter, we explore how information may be represented at the cellular level and processed via coordinated patterns of activity throughout the subregions of the hippocampal network.
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Affiliation(s)
- Marielena Sosa
- Kavli Institute for Fundamental Neuroscience and Department of Physiology, University of California, San Francisco, USA
| | | | - Loren M Frank
- Kavli Institute for Fundamental Neuroscience and Department of Physiology, University of California, San Francisco, USA. .,Howard Hughes Medical Institute, Maryland, USA.
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17
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Gerber KJ, Squires KE, Hepler JR. Roles for Regulator of G Protein Signaling Proteins in Synaptic Signaling and Plasticity. Mol Pharmacol 2015; 89:273-86. [PMID: 26655302 DOI: 10.1124/mol.115.102210] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 12/10/2015] [Indexed: 11/22/2022] Open
Abstract
The regulator of G protein signaling (RGS) family of proteins serves critical roles in G protein-coupled receptor (GPCR) and heterotrimeric G protein signal transduction. RGS proteins are best understood as negative regulators of GPCR/G protein signaling. They achieve this by acting as GTPase activating proteins (GAPs) for Gα subunits and accelerating the turnoff of G protein signaling. Many RGS proteins also bind additional signaling partners that either regulate their functions or enable them to regulate other important signaling events. At neuronal synapses, GPCRs, G proteins, and RGS proteins work in coordination to regulate key aspects of neurotransmitter release, synaptic transmission, and synaptic plasticity, which are necessary for central nervous system physiology and behavior. Accumulating evidence has revealed key roles for specific RGS proteins in multiple signaling pathways at neuronal synapses, regulating both pre- and postsynaptic signaling events and synaptic plasticity. Here, we review and highlight the current knowledge of specific RGS proteins (RGS2, RGS4, RGS7, RGS9-2, and RGS14) that have been clearly demonstrated to serve critical roles in modulating synaptic signaling and plasticity throughout the brain, and we consider their potential as future therapeutic targets.
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Affiliation(s)
- Kyle J Gerber
- Programs in Molecular and Systems Pharmacology (K.J.G., K.E.S., J.R.H.) and Neuroscience (J.R.H.), Department of Pharmacology (K.J.G., K.E.S., J.R.H.), Emory University School of Medicine, Atlanta, Georgia
| | - Katherine E Squires
- Programs in Molecular and Systems Pharmacology (K.J.G., K.E.S., J.R.H.) and Neuroscience (J.R.H.), Department of Pharmacology (K.J.G., K.E.S., J.R.H.), Emory University School of Medicine, Atlanta, Georgia
| | - John R Hepler
- Programs in Molecular and Systems Pharmacology (K.J.G., K.E.S., J.R.H.) and Neuroscience (J.R.H.), Department of Pharmacology (K.J.G., K.E.S., J.R.H.), Emory University School of Medicine, Atlanta, Georgia
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18
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Evans PR, Dudek SM, Hepler JR. Regulator of G Protein Signaling 14: A Molecular Brake on Synaptic Plasticity Linked to Learning and Memory. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 133:169-206. [PMID: 26123307 DOI: 10.1016/bs.pmbts.2015.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The regulators of G protein signaling (RGS) proteins are a diverse family of proteins that function as central components of G protein and other signaling pathways. In the brain, regulator of G protein signaling 14 (RGS14) is enriched in neurons in the hippocampus where the mRNA and protein are highly expressed. This brain region plays a major role in processing learning and forming new memories. RGS14 is an unusual RGS protein that acts as a multifunctional scaffolding protein to integrate signaling events and pathways essential for synaptic plasticity, including conventional and unconventional G protein signaling, mitogen-activated protein kinase, and, possibly, calcium signaling pathways. Within the hippocampus of primates and rodents, RGS14 is predominantly found in the enigmatic CA2 subfield. Principal neurons within the CA2 subfield differ from neighboring hippocampal regions in that they lack a capacity for long-term potentiation (LTP) of synaptic transmission, which is widely viewed as the cellular substrate of learning and memory formation. RGS14 was recently identified as a natural suppressor of LTP in hippocampal CA2 neurons as well as forms of learning and memory that depend on the hippocampus. Although CA2 has only recently been studied, compelling recent evidence implicates area CA2 as a critical component of hippocampus circuitry with functional roles in mediating certain types of learning and memory. This review will highlight the known functions of RGS14 in cell signaling and hippocampus physiology, and discuss potential roles for RGS14 in human cognition and disease.
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Affiliation(s)
- Paul R Evans
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, Atlanta, Georgia, USA
| | - Serena M Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - John R Hepler
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, Atlanta, Georgia, USA.
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19
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Brown NE, Goswami D, Branch MR, Ramineni S, Ortlund EA, Griffin PR, Hepler JR. Integration of G protein α (Gα) signaling by the regulator of G protein signaling 14 (RGS14). J Biol Chem 2015; 290:9037-49. [PMID: 25666614 DOI: 10.1074/jbc.m114.634329] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Indexed: 11/06/2022] Open
Abstract
RGS14 contains distinct binding sites for both active (GTP-bound) and inactive (GDP-bound) forms of Gα subunits. The N-terminal regulator of G protein signaling (RGS) domain binds active Gαi/o-GTP, whereas the C-terminal G protein regulatory (GPR) motif binds inactive Gαi1/3-GDP. The molecular basis for how RGS14 binds different activation states of Gα proteins to integrate G protein signaling is unknown. Here we explored the intramolecular communication between the GPR motif and the RGS domain upon G protein binding and examined whether RGS14 can functionally interact with two distinct forms of Gα subunits simultaneously. Using complementary cellular and biochemical approaches, we demonstrate that RGS14 forms a stable complex with inactive Gαi1-GDP at the plasma membrane and that free cytosolic RGS14 is recruited to the plasma membrane by activated Gαo-AlF4(-). Bioluminescence resonance energy transfer studies showed that RGS14 adopts different conformations in live cells when bound to Gα in different activation states. Hydrogen/deuterium exchange mass spectrometry revealed that RGS14 is a very dynamic protein that undergoes allosteric conformational changes when inactive Gαi1-GDP binds the GPR motif. Pure RGS14 forms a ternary complex with Gαo-AlF4(-) and an AlF4(-)-insensitive mutant (G42R) of Gαi1-GDP, as observed by size exclusion chromatography and differential hydrogen/deuterium exchange. Finally, a preformed RGS14·Gαi1-GDP complex exhibits full capacity to stimulate the GTPase activity of Gαo-GTP, demonstrating that RGS14 can functionally engage two distinct forms of Gα subunits simultaneously. Based on these findings, we propose a working model for how RGS14 integrates multiple G protein signals in host CA2 hippocampal neurons to modulate synaptic plasticity.
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Affiliation(s)
| | - Devrishi Goswami
- the Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458
| | | | | | - Eric A Ortlund
- Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322 and
| | - Patrick R Griffin
- the Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458
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Ortiz-Matamoros A, Salcedo-Tello P, Avila-Muñoz E, Zepeda A, Arias C. Role of wnt signaling in the control of adult hippocampal functioning in health and disease: therapeutic implications. Curr Neuropharmacol 2014; 11:465-76. [PMID: 24403870 PMCID: PMC3763754 DOI: 10.2174/1570159x11311050001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/16/2013] [Accepted: 03/16/2013] [Indexed: 12/12/2022] Open
Abstract
It is well recognized the role of the Wnt pathway in many developmental processes such as neuronal maturation, migration, neuronal connectivity and synaptic formation. Growing evidence is also demonstrating its function in the mature brain where is associated with modulation of axonal remodeling, dendrite outgrowth, synaptic activity, neurogenesis and behavioral plasticity. Proteins involved in Wnt signaling have been found expressed in the adult hippocampus suggesting that Wnt pathway plays a role in the hippocampal function through life. Indeed, Wnt ligands act locally to regulate neurogenesis, neuronal cell shape and pre- and postsynaptic assembly, events that are thought to underlie changes in synaptic function associated with long-term potentiation and with cognitive tasks such as learning and memory. Recent data have demonstrated the increased expression of the Wnt antagonist Dickkopf-1 (DKK1) in brains of Alzheimer´s disease (AD) patients suggesting that dysfunction of Wnt signaling could also contribute to AD pathology. We review here evidence of Wnt-associated molecules expression linked to physiological and pathological hippocampal functioning in the adult brain. The basic aspects of Wnt related mechanisms underlying hippocampal plasticity as well as evidence of how hippocampal dysfunction may rely on Wnt dysregulation is analyzed. This information would provide some clues about the possible therapeutic targets for developing treatments for neurodegenerative diseases associated with aberrant brain plasticity.
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Affiliation(s)
- Abril Ortiz-Matamoros
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F
| | - Pamela Salcedo-Tello
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F
| | - Evangelina Avila-Muñoz
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F
| | - Angélica Zepeda
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F
| | - Clorinda Arias
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F
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21
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Evans PR, Lee SE, Smith Y, Hepler JR. Postnatal developmental expression of regulator of G protein signaling 14 (RGS14) in the mouse brain. J Comp Neurol 2014; 522:186-203. [PMID: 23817783 PMCID: PMC3883939 DOI: 10.1002/cne.23395] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 04/22/2013] [Accepted: 06/19/2013] [Indexed: 12/13/2022]
Abstract
Regulator of G protein signaling 14 (RGS14) is a multifunctional scaffolding protein that integrates G protein and mitogen-activated protein kinase (MAPK) signaling pathways. In the adult mouse brain, RGS14 mRNA and protein are found almost exclusively in hippocampal CA2 neurons. We have shown that RGS14 is a natural suppressor of CA2 synaptic plasticity and hippocampal-dependent learning and memory. However, the protein distribution and spatiotemporal expression patterns of RGS14 in mouse brain during postnatal development are unknown. Here, using a newly characterized monoclonal anti-RGS14 antibody, we demonstrate that RGS14 protein immunoreactivity is undetectable at birth (P0), with very low mRNA expression in the brain. However, RGS14 protein and mRNA are upregulated during early postnatal development, with protein first detected at P7, and both increasing over time until reaching highest sustained levels throughout adulthood. Our immunoperoxidase data demonstrate that RGS14 protein is expressed in regions outside of hippocampal CA2 during development including the primary olfactory areas, the anterior olfactory nucleus and piriform cortex, and the olfactory associated orbital and entorhinal cortices. RGS14 is also transiently expressed in neocortical layers II/III and V during postnatal development. Finally, we show that RGS14 protein is first detected in the hippocampus at P7, with strongest immunoreactivity in CA2 and fasciola cinerea and sporadic immunoreactivity in CA1; labeling intensity in hippocampus increases until adulthood. These results show that RGS14 mRNA and protein are upregulated throughout postnatal mouse development, and RGS14 protein exhibits a dynamic localization pattern that is enriched in hippocampus and primary olfactory cortex in the adult mouse brain.
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Affiliation(s)
- Paul R Evans
- Department of Pharmacology, Emory University, Atlanta, Georgia, 30322
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22
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Bando SY, Silva FN, Costa LDF, Silva AV, Pimentel-Silva LR, Castro LHM, Wen HT, Amaro E, Moreira-Filho CA. Complex network analysis of CA3 transcriptome reveals pathogenic and compensatory pathways in refractory temporal lobe epilepsy. PLoS One 2013; 8:e79913. [PMID: 24278214 PMCID: PMC3836787 DOI: 10.1371/journal.pone.0079913] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 09/25/2013] [Indexed: 12/21/2022] Open
Abstract
We previously described - studying transcriptional signatures of hippocampal CA3 explants - that febrile (FS) and afebrile (NFS) forms of refractory mesial temporal lobe epilepsy constitute two distinct genomic phenotypes. That network analysis was based on a limited number (hundreds) of differentially expressed genes (DE networks) among a large set of valid transcripts (close to two tens of thousands). Here we developed a methodology for complex network visualization (3D) and analysis that allows the categorization of network nodes according to distinct hierarchical levels of gene-gene connections (node degree) and of interconnection between node neighbors (concentric node degree). Hubs are highly connected nodes, VIPs have low node degree but connect only with hubs, and high-hubs have VIP status and high overall number of connections. Studying the whole set of CA3 valid transcripts we: i) obtained complete transcriptional networks (CO) for FS and NFS phenotypic groups; ii) examined how CO and DE networks are related; iii) characterized genomic and molecular mechanisms underlying FS and NFS phenotypes, identifying potential novel targets for therapeutic interventions. We found that: i) DE hubs and VIPs are evenly distributed inside the CO networks; ii) most DE hubs and VIPs are related to synaptic transmission and neuronal excitability whereas most CO hubs, VIPs and high hubs are related to neuronal differentiation, homeostasis and neuroprotection, indicating compensatory mechanisms. Complex network visualization and analysis is a useful tool for systems biology approaches to multifactorial diseases. Network centrality observed for hubs, VIPs and high hubs of CO networks, is consistent with the network disease model, where a group of nodes whose perturbation leads to a disease phenotype occupies a central position in the network. Conceivably, the chance for exerting therapeutic effects through the modulation of particular genes will be higher if these genes are highly interconnected in transcriptional networks.
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Affiliation(s)
- Silvia Yumi Bando
- Department of Pediatrics, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, São Paulo, Brazil
| | | | | | - Alexandre V. Silva
- Department of Biosciences, Universidade Federal de São Paulo, Santos, São Paulo, Brazil
| | | | - Luiz HM. Castro
- Clinical Neurology Division, Hospital das Clínicas da FMUSP, São Paulo, São Paulo, Brazil
| | - Hung-Tzu Wen
- Epilepsy Surgery Group, Hospital das Clínicas da FMUSP, São Paulo, São Paulo, Brazil
| | - Edson Amaro
- Department of Radiology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, São Paulo, Brazil
| | - Carlos Alberto Moreira-Filho
- Department of Pediatrics, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, São Paulo, Brazil
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Phosducin-like protein 1 is essential for G-protein assembly and signaling in retinal rod photoreceptors. J Neurosci 2013; 33:7941-51. [PMID: 23637185 DOI: 10.1523/jneurosci.5001-12.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
G-protein β subunits perform essential neuronal functions as part of G-protein βγ and Gβ5-regulators of G-protein signaling (RGS) complexes. Both Gβγ and Gβ5-RGS are obligate dimers that are thought to require the assistance of the cytosolic chaperonin CCT and a cochaperone, phosducin-like protein 1 (PhLP1) for dimer formation. To test this hypothesis in vivo, we deleted the Phlp1 gene in mouse (Mus musculus) retinal rod photoreceptor cells and measured the effects on G-protein biogenesis and visual signal transduction. In the PhLP1-depleted rods, Gβγ dimer formation was decreased 50-fold, resulting in a >10-fold decrease in light sensitivity. Moreover, a 20-fold reduction in Gβ5 and RGS9-1 expression was also observed, causing a 15-fold delay in the shutoff of light responses. These findings conclusively demonstrate in vivo that PhLP1 is required for the folding and assembly of both Gβγ and Gβ5-RGS9.
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Vellano CP, Brown NE, Blumer JB, Hepler JR. Assembly and function of the regulator of G protein signaling 14 (RGS14)·H-Ras signaling complex in live cells are regulated by Gαi1 and Gαi-linked G protein-coupled receptors. J Biol Chem 2012; 288:3620-31. [PMID: 23250758 DOI: 10.1074/jbc.m112.440057] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Regulator of G protein signaling 14 (RGS14) is a multifunctional scaffolding protein that integrates heterotrimeric G protein and H-Ras signaling pathways. RGS14 possesses an RGS domain that binds active Gα(i/o)-GTP subunits to promote GTP hydrolysis and a G protein regulatory (GPR) motif that selectively binds inactive Gα(i1/3)-GDP subunits to form a stable heterodimer at cellular membranes. RGS14 also contains two tandem Ras/Rap binding domains (RBDs) that bind H-Ras. Here we show that RGS14 preferentially binds activated H-Ras-GTP in live cells to enhance H-Ras cellular actions and that this interaction is regulated by inactive Gα(i1)-GDP and G protein-coupled receptors (GPCRs). Using bioluminescence resonance energy transfer (BRET) in live cells, we show that RGS14-Luciferase and active H-Ras(G/V)-Venus exhibit a robust BRET signal at the plasma membrane that is markedly enhanced in the presence of inactive Gα(i1)-GDP but not active Gα(i1)-GTP. Active H-Ras(G/V) interacts with a native RGS14·Gα(i1) complex in brain lysates, and co-expression of RGS14 and Gα(i1) in PC12 cells greatly enhances H-Ras(G/V) stimulatory effects on neurite outgrowth. Stimulation of the Gα(i)-linked α(2A)-adrenergic receptor induces a conformational change in the Gα(i1)·RGS14·H-Ras(G/V) complex that may allow subsequent regulation of the complex by other binding partners. Together, these findings indicate that inactive Gα(i1)-GDP enhances the affinity of RGS14 for H-Ras-GTP in live cells, resulting in a ternary signaling complex that is further regulated by GPCRs.
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Affiliation(s)
- Christopher P Vellano
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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25
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Caruana DA, Alexander GM, Dudek SM. New insights into the regulation of synaptic plasticity from an unexpected place: hippocampal area CA2. Learn Mem 2012; 19:391-400. [PMID: 22904370 DOI: 10.1101/lm.025304.111] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The search for molecules that restrict synaptic plasticity in the brain has focused primarily on sensory systems during early postnatal development, as critical periods for inducing plasticity in sensory regions are easily defined. The recent discovery that Schaffer collateral inputs to hippocampal area CA2 do not readily support canonical activity-dependent long-term potentiation (LTP) serves as a reminder that the capacity for synaptic modification is also regulated anatomically across different brain regions. Hippocampal CA2 shares features with other similarly "LTP-resistant" brain areas in that many of the genes linked to synaptic function and the associated proteins known to restrict synaptic plasticity are expressed there. Add to this a rich complement of receptors and signaling molecules permissive for induction of atypical forms of synaptic potentiation, and area CA2 becomes an ideal model system for studying specific modulators of brain plasticity. Additionally, recent evidence suggests that hippocampal CA2 is instrumental for certain forms of learning, memory, and social behavior, but the links between CA2-enriched molecules and putative CA2-dependent behaviors are only just beginning to be made. In this review, we offer a detailed look at what is currently known about the synaptic plasticity in this important, yet largely overlooked component of the hippocampus and consider how the study of CA2 may provide clues to understanding the molecular signals critical to the modulation of synaptic function in different brain regions and across different stages of development.
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Affiliation(s)
- Douglas A Caruana
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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Millan MJ, Agid Y, Brüne M, Bullmore ET, Carter CS, Clayton NS, Connor R, Davis S, Deakin B, DeRubeis RJ, Dubois B, Geyer MA, Goodwin GM, Gorwood P, Jay TM, Joëls M, Mansuy IM, Meyer-Lindenberg A, Murphy D, Rolls E, Saletu B, Spedding M, Sweeney J, Whittington M, Young LJ. Cognitive dysfunction in psychiatric disorders: characteristics, causes and the quest for improved therapy. Nat Rev Drug Discov 2012; 11:141-68. [PMID: 22293568 DOI: 10.1038/nrd3628] [Citation(s) in RCA: 784] [Impact Index Per Article: 65.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Studies of psychiatric disorders have traditionally focused on emotional symptoms such as depression, anxiety and hallucinations. However, poorly controlled cognitive deficits are equally prominent and severely compromise quality of life, including social and professional integration. Consequently, intensive efforts are being made to characterize the cellular and cerebral circuits underpinning cognitive function, define the nature and causes of cognitive impairment in psychiatric disorders and identify more effective treatments. Successful development will depend on rigorous validation in animal models as well as in patients, including measures of real-world cognitive functioning. This article critically discusses these issues, highlighting the challenges and opportunities for improving cognition in individuals suffering from psychiatric disorders.
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Affiliation(s)
- Mark J Millan
- Institut de Recherche Servier, 78290 Croissy/Seine, France.
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