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Fullerton EF, Karom MC, Streicher JM, Young LJ, Murphy AZ. Age-Induced Changes in µ-Opioid Receptor Signaling in the Midbrain Periaqueductal Gray of Male and Female Rats. J Neurosci 2022; 42:6232-6242. [PMID: 35790399 PMCID: PMC9374133 DOI: 10.1523/jneurosci.0355-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 04/08/2022] [Accepted: 04/16/2022] [Indexed: 11/21/2022] Open
Abstract
Opioids have decreased analgesic potency (but not efficacy) in aged rodents compared with adults; however, the neural mechanisms underlying this attenuated response are not yet known. The present study investigated the impact of advanced age and biological sex on opioid signaling in the ventrolateral periaqueductal gray (vlPAG) in the presence of chronic inflammatory pain. Assays measuring µ-opioid receptor (MOR) radioligand binding, GTPγS binding, receptor phosphorylation, cAMP inhibition, and regulator of G-protein signaling (RGS) protein expression were performed on vlPAG tissue from adult (2-3 months) and aged (16-18 months) male and female rats. Persistent inflammatory pain was induced by intraplantar injection of complete Freund's adjuvant (CFA). Adult males exhibited the highest MOR binding potential (BP) and highest G-protein activation (activation efficiency ratio) in comparison to aged males and females (adult and aged). No impact of advanced age or sex on MOR phosphorylation state was observed. DAMGO-induced cAMP inhibition was highest in the vlPAG of adult males compared with aged males and females (adult and aged). vlPAG levels of RGS4 and RGS9-2, critical for terminating G-protein signaling, were assessed using RNAscope. Adult rats (both males and females) exhibited lower levels of vlPAG RGS4 and RGS9-2 mRNA expression compared with aged males and females. The observed age-related reductions in vlPAG MOR BP, G-protein activation efficiency, and cAMP inhibition, along with the observed age-related increases in RGS4 and RGS9-2 vlPAG expression, provide potential mechanisms whereby the potency of opioids is decreased in the aged population.SIGNIFICANCE STATEMENT Opioids have decreased analgesic potency (but not efficacy) in aged rodents compared with adults; however, the neural mechanisms underlying this attenuated response are not yet known. In the present study, we observed age-related reductions in ventrolateral periaqueductal gray (vlPAG) µ-opioid receptor (MOR) binding potential (BP), G-protein activation efficiency, and cAMP inhibition, along with the observed age-related increases in regulator of G-protein signaling (RGS)4 and RGS9-2 vlPAG expression, providing potential mechanisms whereby the potency of opioids is decreased in the aged population. These coordinated decreases in opioid receptor signaling may explain the previously reported reduced potency of opioids to produce pain relief in females and aged rats.
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Affiliation(s)
- Evan F Fullerton
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
| | - Mary C Karom
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
| | - John M Streicher
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724
| | - Larry J Young
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Anne Z Murphy
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
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Chinn IK, Xie Z, Chan EC, Nagata BM, Koval A, Chen WS, Zhang F, Ganesan S, Hong DN, Suzuki M, Nardone G, Moore IN, Katanaev VL, Balazs AE, Liu C, Lupski JR, Orange JS, Druey KM. Short stature and combined immunodeficiency associated with mutations in RGS10. Sci Signal 2021; 14:14/693/eabc1940. [PMID: 34315806 DOI: 10.1126/scisignal.abc1940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We report the clinical and molecular phenotype of three siblings from one family, who presented with short stature and immunodeficiency and carried uncharacterized variants in RGS10 (c.489_491del:p.E163del and c.G511T:p.A171S). This gene encodes regulator of G protein signaling 10 (RGS10), a member of a large family of GTPase-activating proteins (GAPs) that targets heterotrimeric G proteins to constrain the activity of G protein-coupled receptors, including receptors for chemoattractants. The affected individuals exhibited systemic abnormalities directly related to the RGS10 mutations, including recurrent infections, hypergammaglobulinemia, profoundly reduced lymphocyte chemotaxis, abnormal lymph node architecture, and short stature due to growth hormone deficiency. Although the GAP activity of each RGS10 variant was intact, each protein exhibited aberrant patterns of PKA-mediated phosphorylation and increased cytosolic and cell membrane localization and activity compared to the wild-type protein. We propose that the RGS10 p.E163del and p.A171S mutations lead to mislocalization of the RGS10 protein in the cytosol, thereby resulting in attenuated chemokine signaling. This study suggests that RGS10 is critical for both immune competence and normal hormonal metabolism in humans and that rare RGS10 variants may contribute to distinct systemic genetic disorders.
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Affiliation(s)
- Ivan K Chinn
- Department of Pediatrics, Texas Children's Hospital and Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhihui Xie
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, NIAID/NIH Bethesda, MD 20892, USA
| | - Eunice C Chan
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, NIAID/NIH Bethesda, MD 20892, USA
| | - Bianca M Nagata
- Infectious Disease Pathogenesis Section, NIAID/NIH, Bethesda, MD 20892, USA
| | - Alexey Koval
- Department of Cell Physiology and Metabolism, Translational Research Centre in Oncohaematology, Faculty of Medicine, University of Geneva, Rue Michel-Servet 1, Geneva CH-1211, Switzerland.,School of Biomedicine, Far Eastern Federal University, 8 ul. Sukhanova, Vladivostok 690950, Russia
| | - Wei-Sheng Chen
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, NIAID/NIH Bethesda, MD 20892, USA
| | - Fan Zhang
- Transgenic Core, NHLBI/NIH, Bethesda, MD 20892 USA
| | - Sundar Ganesan
- Biological Imaging Section, NIAID/NIH Bethesda, MD 20892, USA
| | - Diana N Hong
- Department of Pediatrics, Texas Children's Hospital and Baylor College of Medicine, Houston, TX 77030, USA
| | - Motoshi Suzuki
- Protein Chemistry Section, NIAID/NIH, Bethesda, MD 20892, USA
| | - Glenn Nardone
- Protein Chemistry Section, NIAID/NIH, Bethesda, MD 20892, USA
| | - Ian N Moore
- Infectious Disease Pathogenesis Section, NIAID/NIH, Bethesda, MD 20892, USA
| | - Vladimir L Katanaev
- Department of Cell Physiology and Metabolism, Translational Research Centre in Oncohaematology, Faculty of Medicine, University of Geneva, Rue Michel-Servet 1, Geneva CH-1211, Switzerland.,School of Biomedicine, Far Eastern Federal University, 8 ul. Sukhanova, Vladivostok 690950, Russia
| | - Andrea E Balazs
- Department of Pediatrics, Texas Children's Hospital and Baylor College of Medicine, Houston, TX 77030, USA
| | - Chengyu Liu
- Transgenic Core, NHLBI/NIH, Bethesda, MD 20892 USA
| | - James R Lupski
- Department of Molecular and Human Genetics and Baylor-Hopkins Center for Mendelian Genomics, Baylor College of Medicine, Houston, TX 77030, USA.,Texas Children’s Hospital, Houston, TX 77030, USA
| | - Jordan S Orange
- Columbia University Vagelos College of Physicians and Surgeons and New York-Presbyterian Hospital
| | - Kirk M Druey
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, NIAID/NIH Bethesda, MD 20892, USA.
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Michaelides M, Miller ML, Egervari G, Primeaux SD, Gomez JL, Ellis RJ, Landry JA, Szutorisz H, Hoffman AF, Lupica CR, Loos RJF, Thanos PK, Bray GA, Neumaier JF, Zachariou V, Wang GJ, Volkow ND, Hurd YL. Striatal Rgs4 regulates feeding and susceptibility to diet-induced obesity. Mol Psychiatry 2020; 25:2058-2069. [PMID: 29955167 PMCID: PMC6310669 DOI: 10.1038/s41380-018-0120-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 05/10/2018] [Accepted: 05/14/2018] [Indexed: 12/16/2022]
Abstract
Consumption of high fat, high sugar (western) diets is a major contributor to the current high levels of obesity. Here, we used a multidisciplinary approach to gain insight into the molecular mechanisms underlying susceptibility to diet-induced obesity (DIO). Using positron emission tomography (PET), we identified the dorsal striatum as the brain area most altered in DIO-susceptible rats and molecular studies within this region highlighted regulator of G-protein signaling 4 (Rgs4) within laser-capture micro-dissected striatonigral (SN) and striatopallidal (SP) medium spiny neurons (MSNs) as playing a key role. Rgs4 is a GTPase accelerating enzyme implicated in plasticity mechanisms of SP MSNs, which are known to regulate feeding and disturbances of which are associated with obesity. Compared to DIO-resistant rats, DIO-susceptible rats exhibited increased striatal Rgs4 with mRNA expression levels enriched in SP MSNs. siRNA-mediated knockdown of striatal Rgs4 in DIO-susceptible rats decreased food intake to levels comparable to DIO-resistant animals. Finally, we demonstrated that the human Rgs4 gene locus is associated with increased body weight and obesity susceptibility phenotypes, and that overweight humans exhibit increased striatal Rgs4 protein. Our findings highlight a novel role for involvement of Rgs4 in SP MSNs in feeding and DIO-susceptibility.
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Affiliation(s)
- Michael Michaelides
- Departments of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Biobehavioral Imaging & Molecular Neuropsychopharmacology Unit, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, 21224, USA
- Department of Psychiatry, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Biobehavioral Imaging & Molecular Neuropsychopharmacology Unit, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, 21224, USA
| | - Michael L Miller
- Departments of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Gabor Egervari
- Departments of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Stefany D Primeaux
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
- Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
| | - Juan L Gomez
- Biobehavioral Imaging & Molecular Neuropsychopharmacology Unit, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, 21224, USA
| | - Randall J Ellis
- Biobehavioral Imaging & Molecular Neuropsychopharmacology Unit, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, 21224, USA
| | - Joseph A Landry
- Departments of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Henrietta Szutorisz
- Departments of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Alexander F Hoffman
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, 21224, USA
| | - Carl R Lupica
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, 21224, USA
| | - Ruth J F Loos
- The Charles Bronfman Institute for Personalized Medicine, The Mindich Child Health and Development Institute, The Genetics of Obesity and Related Metabolic Traits Program, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Panayotis K Thanos
- Research Institute on Addictions, University at Buffalo, Buffalo, NY, 14203, USA
| | - George A Bray
- Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
| | - John F Neumaier
- Departments of Psychiatry and Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | - Venetia Zachariou
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Gene-Jack Wang
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Nora D Volkow
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yasmin L Hurd
- Departments of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
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Squires KE, Montañez-Miranda C, Pandya RR, Torres MP, Hepler JR. Genetic Analysis of Rare Human Variants of Regulators of G Protein Signaling Proteins and Their Role in Human Physiology and Disease. Pharmacol Rev 2018; 70:446-474. [PMID: 29871944 DOI: 10.1124/pr.117.015354] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Regulators of G protein signaling (RGS) proteins modulate the physiologic actions of many neurotransmitters, hormones, and other signaling molecules. Human RGS proteins comprise a family of 20 canonical proteins that bind directly to G protein-coupled receptors/G protein complexes to limit the lifetime of their signaling events, which regulate all aspects of cell and organ physiology. Genetic variations account for diverse human traits and individual predispositions to disease. RGS proteins contribute to many complex polygenic human traits and pathologies such as hypertension, atherosclerosis, schizophrenia, depression, addiction, cancers, and many others. Recent analysis indicates that most human diseases are due to extremely rare genetic variants. In this study, we summarize physiologic roles for RGS proteins and links to human diseases/traits and report rare variants found within each human RGS protein exome sequence derived from global population studies. Each RGS sequence is analyzed using recently described bioinformatics and proteomic tools for measures of missense tolerance ratio paired with combined annotation-dependent depletion scores, and protein post-translational modification (PTM) alignment cluster analysis. We highlight selected variants within the well-studied RGS domain that likely disrupt RGS protein functions and provide comprehensive variant and PTM data for each RGS protein for future study. We propose that rare variants in functionally sensitive regions of RGS proteins confer profound change-of-function phenotypes that may contribute, in newly appreciated ways, to complex human diseases and/or traits. This information provides investigators with a valuable database to explore variation in RGS protein function, and for targeting RGS proteins as future therapeutic targets.
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Affiliation(s)
- Katherine E Squires
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Carolina Montañez-Miranda
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Rushika R Pandya
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Matthew P Torres
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - John R Hepler
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
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Kimoto S, Glausier JR, Fish KN, Volk DW, Bazmi HH, Arion D, Datta D, Lewis DA. Reciprocal Alterations in Regulator of G Protein Signaling 4 and microRNA16 in Schizophrenia. Schizophr Bull 2016; 42:396-405. [PMID: 26424323 PMCID: PMC4753606 DOI: 10.1093/schbul/sbv139] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
N-methyl-d-aspartate receptor (NMDAR) hypofunction in the dorsolateral prefrontal cortex (DLPFC) has been implicated in the pathology of schizophrenia. NMDAR activity is negatively regulated by some G protein-coupled receptors (GPCRs). Signaling through these GPCRs is reduced by Regulator of G protein Signaling 4 (RGS4). Thus, lower levels of RGS4 would enhance GPCR-mediated reductions in NMDAR activity and could contribute to NMDAR hypofunction in schizophrenia. In this study, we quantified RGS4 mRNA and protein levels at several levels of resolution in the DLPFC from subjects with schizophrenia and matched healthy comparison subjects. To investigate molecular mechanisms that could contribute to altered RGS4 levels, we quantified levels of small noncoding RNAs, known as microRNAs (miRs), which regulate RGS4 mRNA integrity after transcription. RGS4 mRNA and protein levels were significantly lower in schizophrenia subjects and were positively correlated across all subjects. The RGS4 mRNA deficit was present in pyramidal neurons of DLPFC layers 3 and 5 of the schizophrenia subjects. In contrast, levels of miR16 were significantly higher in the DLPFC of schizophrenia subjects, and higher miR16 levels predicted lower RGS4 mRNA levels. These findings provide convergent evidence of lower RGS4 mRNA and protein levels in schizophrenia that may result from increased expression of miR16. Given the role of RGS4 in regulating GPCRs, and consequently the strength of NMDAR signaling, these findings could contribute to the molecular substrate for NMDAR hypofunction in DLPFC pyramidal cells in schizophrenia.
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Affiliation(s)
- Sohei Kimoto
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA; Department of Psychiatry, Nara Medical University, Nara, Japan
| | - Jill R Glausier
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Kenneth N Fish
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - David W Volk
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - H Holly Bazmi
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Dominique Arion
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Dibyadeep Datta
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - David A Lewis
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA; Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA
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Hou J, Archer KJ. Regularization method for predicting an ordinal response using longitudinal high-dimensional genomic data. Stat Appl Genet Mol Biol 2015; 14:93-111. [PMID: 25720102 PMCID: PMC4454613 DOI: 10.1515/sagmb-2014-0004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract An ordinal scale is commonly used to measure health status and disease related outcomes in hospital settings as well as in translational medical research. In addition, repeated measurements are common in clinical practice for tracking and monitoring the progression of complex diseases. Classical methodology based on statistical inference, in particular, ordinal modeling has contributed to the analysis of data in which the response categories are ordered and the number of covariates (p) remains smaller than the sample size (n). With the emergence of genomic technologies being increasingly applied for more accurate diagnosis and prognosis, high-dimensional data where the number of covariates (p) is much larger than the number of samples (n), are generated. To meet the emerging needs, we introduce our proposed model which is a two-stage algorithm: Extend the generalized monotone incremental forward stagewise (GMIFS) method to the cumulative logit ordinal model; and combine the GMIFS procedure with the classical mixed-effects model for classifying disease status in disease progression along with time. We demonstrate the efficiency and accuracy of the proposed models in classification using a time-course microarray dataset collected from the Inflammation and the Host Response to Injury study.
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Affiliation(s)
- Jiayi Hou
- Department of Biostatistics, Virginia Commonwealth University.
| | - Kellie J. Archer
- Department of Biostatistics, Virginia Commonwealth University, 830 East Main St., Room 718, Richmond, VA 23298-0032, United States.
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Physiology of RGS10 in Neurons and Immune Cells. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 133:153-67. [DOI: 10.1016/bs.pmbts.2015.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Brain RGS4 and RGS10 protein expression in schizophrenia and depression. Effect of drug treatment. Psychopharmacology (Berl) 2013; 226:177-88. [PMID: 23093381 DOI: 10.1007/s00213-012-2888-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 10/02/2012] [Indexed: 02/07/2023]
Abstract
RATIONALE Regulator of G-protein signaling (RGS) proteins, RGS4 and RGS10, may be involved in the pathophysiology of schizophrenia. RGS4 has attracted special interest since the reports of genetic association between SNPs in RGS4 and schizophrenia. However, there is no information about the subcellular distribution of RGS4 and RGS10 proteins in psychiatric disorders. OBJECTIVES Plasma membrane RGS4 and cytosolic RGS10 protein immunoreactivity in prefrontal cortex from schizophrenic subjects (n = 25), non-diagnosed suicides (n = 13), and control subjects (n = 35), matched by age, gender, and postmortem delay, was analyzed by western blot. A second group of depressed subjects (n = 25) and control subjects (n = 25) was evaluated. The effect of the antipsychotic or antidepressant treatments was also assessed. RESULTS No significant differences in plasma membrane RGS4 and cytosolic RGS10 protein expression were observed between schizophrenic subjects, non-diagnosed suicides, and control subjects. However, RGS4 immunoreactivity was significantly higher (Δ = 33 ± 10 %, p < 0.05) in the antipsychotic-treated subgroup (n = 12) than in the antipsychotic-free subgroup (n = 13). Immunodensities of plasma membrane RGS4 and cytosolic RGS10 proteins did not differ between depressed and matched control subjects. CONCLUSIONS Expression of RGS4 and RGS10 proteins at their predominant subcellular location was studied in the postmortem brain of subjects with psychiatric disorders. The results suggest unaltered membrane RGS4 and cytosolic RGS10 proteins levels in schizophrenia and major depression. Antipsychotic treatment seems to increase membrane RGS4 immunoreactivity. Further studies are needed to elucidate RGS4 and RGS10 functional status.
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Differential regulation of RGS proteins in the prefrontal cortex of short- and long-term human opiate abusers. Neuropharmacology 2011; 62:1044-51. [PMID: 22056472 DOI: 10.1016/j.neuropharm.2011.10.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 10/20/2011] [Accepted: 10/24/2011] [Indexed: 12/20/2022]
Abstract
Opiate addiction is characterized by drug tolerance and dependence which involve adaptive changes in μ-opioid receptors (MORs) signaling. Regulators of G-protein signaling RGS9, RGS4 and RGS10 proteins negatively regulate G(αi/o) protein activity modulating MOR function. An important role of RGS proteins in drug addiction has been described but the status of RGS proteins in human brain of opiate addicts remains unknown. The present study evaluated the immunoreactivity levels of RGS4, RGS9 and RGS10 proteins in prefrontal cortex of short- (n = 15) and long-term (n = 21) opiate abusers and in matched control subjects. RGS4 protein was not altered in short-term opiate abusers but, in long-term abusers it was significantly up-regulated (Δ = 29 ± 6%). RGS10 protein expression was significantly decreased in short-term (Δ = -42 ± 7%) but remained unaltered in long-term opiate abusers. RGS9 protein levels in opiate abusers did not differ from matched controls either in the short-term or in the long-term opiate abuser groups. RGS4, RGS9 and RGS10 levels were also studied in brains (frontal cortex) of rats submitted to acute and chronic morphine treatment and to spontaneous and naloxone-precipitated opiate withdrawal. Chronic morphine treatment in rats was associated with an increase in RGS4 protein immunoreactivity (Δ = 28 ± 7%), which persisted in spontaneous (Δ = 35 ± 8%) and naloxone-precipitated withdrawal (Δ = 30 ± 9%) without significant changes in RGS9 and RGS10 proteins. The specific modulation of RGS4 and RGS10 protein expression observed in the prefrontal cortex of opiate abusers might be relevant in the neurobiology of opiate tolerance, dependence and withdrawal. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.
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