1
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Bernhard SM, Han J, Che T. GPCR-G protein selectivity revealed by structural pharmacology. FEBS J 2023. [PMID: 38151714 DOI: 10.1111/febs.17049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/28/2023] [Accepted: 12/27/2023] [Indexed: 12/29/2023]
Abstract
Receptor-G protein promiscuity is frequently observed in class A G protein-coupled receptors (GPCRs). In particular, GPCRs can couple with G proteins from different families (Gαs, Gαq/11, Gαi/o, and Gα12/13) or the same family subtypes. The molecular basis underlying the selectivity/promiscuity is not fully revealed. We recently reported the structures of kappa opioid receptor (KOR) in complex with the Gi/o family subtypes [Gαi1, GαoA, Gαz, and Gustducin (Gαg)] determined by cryo-electron microscopy (cryo-EM). The structural analysis, in combination with pharmacological studies, provides insights into Gi/o subtype selectivity. Given the conserved sequence identity and activation mechanism between different G protein families, the findings within Gi/o subtypes could be likely extended to other families. Understanding the KOR-Gi/o or GPCR-G protein selectivity will facilitate the development of more precise therapeutics targeting a specific G protein subtype.
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Affiliation(s)
- Sarah M Bernhard
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, St. Louis, MO, USA
| | - Jianming Han
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, St. Louis, MO, USA
| | - Tao Che
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, St. Louis, MO, USA
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2
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Alabdali R, Franchini L, Orlandi C. G α Protein Signaling Bias at Serotonin 1A Receptor. Mol Pharmacol 2023; 104:230-238. [PMID: 37567783 PMCID: PMC10586511 DOI: 10.1124/molpharm.123.000722] [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: 05/18/2023] [Revised: 07/11/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
Serotonin 1A receptor (5-HT1AR) is a clinically relevant target because of its involvement in several central and peripheral functions, including sleep, temperature homeostasis, processing of emotions, and response to stress. As a G protein coupled receptor (GPCR) activating numerous Gα i/o/z family members, 5-HT1AR can potentially modulate multiple intracellular signaling pathways in response to different therapeutics. Here, we applied a cell-based bioluminescence resonance energy transfer assay to quantify how ten structurally diverse 5-HT1AR agonists exert biased signaling by differentially stimulating Gα i/o/z family members. Our concentration-response analysis of the activation of each Gα i/o/z protein revealed unique potency and efficacy profiles of selected agonists when compared with the reference 5-hydroxytryptamine, serotonin. Overall, our analysis of signaling bias identified groups of ligands sharing comparable G protein activation selectivity and also drugs with unique selectivity profiles. We observed, for example, a strong bias of F-15599 toward the activation of Gα i3 that was unique among the agonists tested: we found a biased factor of +2.19 when comparing the activation of Gα i3 versus Gα i2 by F-15599, while it was -0.29 for 8-hydroxy-2-(di-n-propylamino) tetralin. Similarly, vortioxetine showed a biased factor of +1.06 for Gα z versus Gα oA, while it was -1.38 for vilazodone. Considering that alternative signaling pathways are regulated downstream of each Gα protein, our data suggest that the unique pharmacological properties of the tested agonists could result in multiple unrelated cellular outcomes. Further investigation is needed to reveal how this type of ligand bias could affect cellular responses and to illuminate the molecular mechanisms underlying therapeutic profile and side effects of each drug. SIGNIFICANCE STATEMENT: Serotonin 1a receptor (5-HT1AR) activates several members of the Gi/o/z protein family. Here, we examined ten structurally diverse and clinically relevant agonists acting on 5-HT1AR and identified distinctive bias patterns among G proteins. Considering the diversity of their intracellular effectors and signaling properties, this data reveal novel mechanisms underlying both therapeutic and undesirable effects.
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Affiliation(s)
- Rana Alabdali
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY
| | - Luca Franchini
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY
| | - Cesare Orlandi
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY
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3
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Moore SJ, Murphy GG, Cazares VA. Turning strains into strengths for understanding psychiatric disorders. Mol Psychiatry 2020; 25:3164-3177. [PMID: 32404949 PMCID: PMC7666068 DOI: 10.1038/s41380-020-0772-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/23/2020] [Accepted: 04/29/2020] [Indexed: 12/12/2022]
Abstract
There is a paucity in the development of new mechanistic insights and therapeutic approaches for treating psychiatric disease. One of the major challenges is reflected in the growing consensus that risk for these diseases is not determined by a single gene, but rather is polygenic, arising from the action and interaction of multiple genes. Canonically, experimental models in mice have been designed to ascertain the relative contribution of a single gene to a disease by systematic manipulation (e.g., mutation or deletion) of a known candidate gene. Because these studies have been largely carried out using inbred isogenic mouse strains, in which there is no (or very little) genetic diversity among subjects, it is difficult to identify unique allelic variants, gene modifiers, and epigenetic factors that strongly affect the nature and severity of these diseases. Here, we review various methods that take advantage of existing genetic diversity or that increase genetic variance in mouse models to (1) strengthen conclusions of single-gene function; (2) model diversity among human populations; and (3) dissect complex phenotypes that arise from the actions of multiple genes.
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Affiliation(s)
- Shannon J Moore
- Michigan Neuroscience Institute & Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Geoffrey G Murphy
- Michigan Neuroscience Institute & Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
| | - Victor A Cazares
- Michigan Neuroscience Institute & Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
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4
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van den Buuse M, Halley P, Hoyne GF. Behavioural phenotyping of thunder mice with a hypomorphic mutation of heterogeneous nuclear ribonuclear protein L-like (hnRNPLL) and reduced T cell function. Neurosci Lett 2020; 740:135469. [PMID: 33152455 DOI: 10.1016/j.neulet.2020.135469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 09/23/2020] [Accepted: 10/27/2020] [Indexed: 02/01/2023]
Abstract
Heterogeneous nuclear ribonuclear protein l-like (hnRNPLL) is an RNA binding protein that regulates alternative splicing of mRNA and is abundantly expressed in memory T lymphocytes of the immune system and in the brain. A hypomorphic allele of the gene encoding hnRNPLL (Hnrpllthunder) selectively reduces T cell accumulation in lymphoid tissues, but little is known about its effects in the brain. Therefore, we exposed Hnrpllthunder mice to a test battery with relevance for a range of psychiatric illnesses. Thunder mice showed enhanced immobility in the tail-suspension test for depression-related behaviours, impaired short-term spatial memory in the Y-maze and reduced avoidance learning in the active avoidance test. Thus, in addition to its reported effects on immune function, the hnRNPLL mutation in thunder mice selectively affected aspects of behaviour.
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Affiliation(s)
- Maarten van den Buuse
- Mental Health Research Institute of Victoria, Parkville, VIC, Australia; School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia.
| | - Paul Halley
- Mental Health Research Institute of Victoria, Parkville, VIC, Australia
| | - Gerard F Hoyne
- Immunology Program, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia; School of Health Sciences, University of Notre Dame Australia, Fremantle, WA, Australia
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5
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Giraldo G, Janus C. Phenotypic evaluation of a childhood-onset parkinsonism-dystonia mouse model with inherent postural abnormalities. Brain Res Bull 2020; 166:54-63. [PMID: 33147520 DOI: 10.1016/j.brainresbull.2020.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 09/25/2020] [Accepted: 10/25/2020] [Indexed: 12/19/2022]
Abstract
Mouse models that replicate facets of human neurological diseases are often used at the pre-clinical stage to better understand the underlying mechanisms of a disease and test the target engagement of potential therapeutic interventions. We recently characterized a mouse model of childhood-onset parkinsonism-dystonia, a disease caused by a homozygous loss-of-function mutation in the SLC39A14 gene. The disease manifests itself phenotypically by impairments in locomotor behaviour and postural abnormalities. Our initial characterization of the model revealed that the Slc39a14-/- mice showed altered Mn homeostasis and compromised locomotor performance in vertical pole-descending, horizontal beam-traversing, and rotarod tests (Jenkitkasemwong et al., 2018). However, some of the mice also displayed torticollis and Straub tail. In this study, we investigated whether these postural abnormalities affected the performance in the above motility tests and consequently, biased and compromised the external validity of reported abnormal locomotor profiles. Our analyses showed that the Slc39a14-/- mice displaying torticollis and/or Straub tail had tests scores comparable to scores of their counterparts that never displayed these postural abnormalities. The z-score general index of performance revealed that the Slc39a14-/- model presents a complex pathological motor phenotype relevant to the complexity of phenotypes identified in childhood-onset parkinsonism-dystonia.
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Affiliation(s)
- Genesys Giraldo
- Department of Neuroscience, and CTRND, McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
| | - Christopher Janus
- Department of Neuroscience, and CTRND, McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
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Holgate JY, Tarren JR, Bartlett SE. Sex Specific Alterations in α4*Nicotinic Receptor Expression in the Nucleus Accumbens. Brain Sci 2018; 8:brainsci8040070. [PMID: 29671814 PMCID: PMC5924406 DOI: 10.3390/brainsci8040070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/12/2018] [Accepted: 04/16/2018] [Indexed: 12/11/2022] Open
Abstract
Background: The mechanisms leading from traumatic stress to social, emotional and cognitive impairment and the development of mental illnesses are still undetermined and consequently there remains a critical need to develop therapies for preventing the adverse consequences of traumatic stress. Research indicates nicotinic acetylcholine receptors containing α4 subunits (α4*nAChRs) are both impacted by stress and capable of modulating the stress response. In this study, we investigated whether varenicline, a partial α4β2*nAChR agonist which reduces nicotine, alcohol and sucrose consumption, can reduce stress, a driving factor in substance use disorders. We also examined the effect of stress on nucleus accumbens (NAc) α4*nAChR expression. Methods: Transgenic mice with fluorescent tags attached to α4*nAChRs were administered varenicline and/or yohimbine (a pharmacological stressor) and plasma corticosterone and NAc α4*nAChR expression were measured. A separated group of mice were exposed to maternal separation (MS) during post-natal day (P) 2–14, then restraint stressed (30 min) at six weeks of age. Body weight, anxiety-like behaviours (elevated plus maze), plasma corticosterone and NAc α4*nAChR levels were measured. Results: Varenicline attenuated yohimbine-induced plasma corticosterone increases with no effect on NAc α4*nAChR expression. MS reduced unrestrained plasma corticosterone levels in both sexes. In females, MS increased body weight and NAc α4*nAChR expression, whereas, in males, MS and restraint caused a greater change in anxiety-like behaviours and plasma corticosterone levels. Restraint altered NAc α4*nAChR expression in both male and female MS mice. Conclusions: The effects of stress on NAc α4*nAChR are sex-dependent. While varenicline attenuated acute stress-induced rises in corticosterone levels, future studies are required to determine whether varenicline is effective for relieving the effects of stress.
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Affiliation(s)
- Joan Y Holgate
- Institute of Health and Medical Innovation, Queensland University of Technology, Translational Research Institute, 37 Kent St, Woolloongabba, QLD 4102, Australia.
| | - Josephine R Tarren
- Institute of Health and Medical Innovation, Queensland University of Technology, Translational Research Institute, 37 Kent St, Woolloongabba, QLD 4102, Australia.
| | - Selena E Bartlett
- Institute of Health and Medical Innovation, Queensland University of Technology, Translational Research Institute, 37 Kent St, Woolloongabba, QLD 4102, Australia.
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Lim JWC, Donahoo ALS, Bunt J, Edwards TJ, Fenlon LR, Liu Y, Zhou J, Moldrich RX, Piper M, Gobius I, Bailey TL, Wray NR, Kessaris N, Poo MM, Rubenstein JLR, Richards LJ. EMX1 regulates NRP1-mediated wiring of the mouse anterior cingulate cortex. Development 2016; 142:3746-57. [PMID: 26534986 DOI: 10.1242/dev.119909] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Transcription factors act during cortical development as master regulatory genes that specify cortical arealization and cellular identities. Although numerous transcription factors have been identified as being crucial for cortical development, little is known about their downstream targets and how they mediate the emergence of specific neuronal connections via selective axon guidance. The EMX transcription factors are essential for early patterning of the cerebral cortex, but whether EMX1 mediates interhemispheric connectivity by controlling corpus callosum formation remains unclear. Here, we demonstrate that in mice on the C57Bl/6 background EMX1 plays an essential role in the midline crossing of an axonal subpopulation of the corpus callosum derived from the anterior cingulate cortex. In the absence of EMX1, cingulate axons display reduced expression of the axon guidance receptor NRP1 and form aberrant axonal bundles within the rostral corpus callosum. EMX1 also functions as a transcriptional activator of Nrp1 expression in vitro, and overexpression of this protein in Emx1 knockout mice rescues the midline-crossing phenotype. These findings reveal a novel role for the EMX1 transcription factor in establishing cortical connectivity by regulating the interhemispheric wiring of a subpopulation of neurons within the mouse anterior cingulate cortex.
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Affiliation(s)
- Jonathan W C Lim
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia
| | - Amber-Lee S Donahoo
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia
| | - Jens Bunt
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia
| | - Timothy J Edwards
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia
| | - Laura R Fenlon
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia
| | - Ying Liu
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia
| | - Jing Zhou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Randal X Moldrich
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia
| | - Michael Piper
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia The University of Queensland, The School of Biomedical Sciences, Brisbane 4072, Australia
| | - Ilan Gobius
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia
| | - Timothy L Bailey
- The University of Queensland, Institute for Molecular Bioscience, Brisbane 4072, Australia
| | - Naomi R Wray
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia
| | - Nicoletta Kessaris
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Mu-Ming Poo
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - John L R Rubenstein
- Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, CA 94143, USA Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Linda J Richards
- The University of Queensland, Queensland Brain Institute, Brisbane 4072, Australia The University of Queensland, The School of Biomedical Sciences, Brisbane 4072, Australia
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8
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Stevens HE, Vaccarino FM. How animal models inform child and adolescent psychiatry. J Am Acad Child Adolesc Psychiatry 2015; 54:352-9. [PMID: 25901771 PMCID: PMC4407022 DOI: 10.1016/j.jaac.2015.01.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 01/29/2015] [Accepted: 02/09/2015] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Every available approach should be used to advance the field of child and adolescent psychiatry. Biological systems are important for the behavioral problems of children. Close examination of nonhuman animals and the biology and behavior that they share with humans is an approach that must be used to advance the clinical work of child psychiatry. METHOD We review here how model systems are used to contribute to significant insights into childhood psychiatric disorders. Model systems have not only demonstrated causality of risk factors for psychiatric pathophysiology, but have also allowed child psychiatrists to think in different ways about risks for psychiatric disorders and multiple levels that might be the basis of recovery and prevention. RESULTS We present examples of how animal systems are used to benefit child psychiatry, including through environmental, genetic, and acute biological manipulations. Animal model work has been essential in our current thinking about childhood disorders, including the importance of dose and timing of risk factors, specific features of risk factors that are significant, neurochemistry involved in brain functioning, molecular components of brain development, and the importance of cellular processes previously neglected in psychiatric theories. CONCLUSION Animal models have clear advantages and disadvantages that must be considered for these systems to be useful. Coupled with increasingly sophisticated methods for investigating human behavior and biology, animal model systems will continue to make essential contributions to our field.
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Affiliation(s)
- Hanna E. Stevens
- University of Iowa Carver College of Medicine, Iowa City and the Child Study Center, Yale School of Medicine, New Haven, CT
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9
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Nichols JL, Gladwell W, Verhein KC, Cho HY, Wess J, Suzuki O, Wiltshire T, Kleeberger SR. Genome-wide association mapping of acute lung injury in neonatal inbred mice. FASEB J 2014; 28:2538-50. [PMID: 24571919 DOI: 10.1096/fj.13-247221] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Reactive oxygen species (ROS) contribute to the pathogenesis of many acute and chronic pulmonary disorders, including bronchopulmonary dysplasia (BPD), a respiratory condition that affects preterm infants. However, the mechanisms of susceptibility to oxidant stress in neonatal lungs are not completely understood. We evaluated the role of genetic background in response to oxidant stress in the neonatal lung by exposing mice from 36 inbred strains to hyperoxia (95% O2) for 72 h after birth. Hyperoxia-induced lung injury was evaluated by using bronchoalveolar lavage fluid (BALF) analysis and pathology. Statistically significant interstrain variation was found for BALF inflammatory cells and protein (heritability estimates range: 33.6-55.7%). Genome-wide association mapping using injury phenotypes identified quantitative trait loci (QTLs) on chromosomes 1, 2, 4, 6, and 7. Comparative mapping of the chromosome 6 QTLs identified Chrm2 (cholinergic receptor, muscarinic 2, cardiac) as a candidate susceptibility gene, and mouse strains with a nonsynonymous coding single-nucleotide polymorphism (SNP) in Chrm2 that causes an amino acid substitution (P265L) had significantly reduced hyperoxia-induced inflammation compared to strains without the SNP. Further, hyperoxia-induced lung injury was significantly reduced in neonatal mice with targeted deletion of Chrm2, relative to wild-type controls. This study has important implications for understanding the mechanisms of oxidative lung injury in neonates.
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Affiliation(s)
- Jennifer L Nichols
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, U.S. National Institutes of Health, Research Triangle Park, North Carolina, USA; Curriculum in Toxicology, Center for Environmental Medicine, Asthma, and Lung Biology, and
| | - Wesley Gladwell
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, U.S. National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Kirsten C Verhein
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, U.S. National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Hye-Youn Cho
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, U.S. National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Jürgen Wess
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, U.S. National Institutes of Health, Bethesda, Maryland, USA
| | - Oscar Suzuki
- Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA; and
| | - Tim Wiltshire
- Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA; and
| | - Steven R Kleeberger
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, U.S. National Institutes of Health, Research Triangle Park, North Carolina, USA;
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Hultman R, Kumari U, Michel N, Casey PJ. Gαz regulates BDNF-induction of axon growth in cortical neurons. Mol Cell Neurosci 2013; 58:53-61. [PMID: 24321455 DOI: 10.1016/j.mcn.2013.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 11/27/2013] [Accepted: 12/03/2013] [Indexed: 01/26/2023] Open
Abstract
The disruption of neurotransmitter and neurotrophic factor signaling in the central nervous system (CNS) is implicated as the root cause of neuropsychiatric disorders, including schizophrenia, epilepsy, chronic pain, and depression. Therefore, identifying the underlying molecular mechanisms by which neurotransmitter and neurotrophic factor signaling regulates neuronal survival or growth may facilitate identification of more effective therapies for these disorders. Previously, our lab found that the heterotrimeric G protein, Gz, mediates crosstalk between G protein-coupled receptors and neurotrophin signaling in the neural cell line PC12. These data, combined with Gαz expression profiles--predominantly in neuronal cells with higher expression levels corresponding to developmental times of target tissue innervation--suggested that Gαz may play an important role in neurotrophin signaling and neuronal development. Here, we provide evidence in cortical neurons, both manipulated ex vivo and those cultured from Gz knockout mice, that Gαz is localized to axonal growth cones and plays a significant role in the development of axons of cortical neurons in the CNS. Our findings indicate that Gαz inhibits BDNF-stimulated axon growth in cortical neurons, establishing an endogenous role for Gαz in regulating neurotrophin signaling in the CNS.
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Affiliation(s)
- Rainbo Hultman
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA; Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Republic of Singapore
| | - Udhaya Kumari
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Republic of Singapore
| | - Nadine Michel
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Patrick J Casey
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Republic of Singapore.
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11
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van den Buuse M. Exploring the role of 5-HT1A receptors in the regulation of prepulse inhibition in mice: implications for cross-species comparisons. ACS Chem Neurosci 2013; 4:149-60. [PMID: 23336054 DOI: 10.1021/cn300118t] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 12/18/2012] [Indexed: 12/20/2022] Open
Abstract
Prepulse inhibition (PPI) is a model of sensorimotor gating, a sensory filtering mechanism which is disrupted in schizophrenia. Here, investigation of the role of the serotonin-1A (5-HT(1A)) receptor in the regulation of PPI in two mouse strains, C57Bl/6 and Balb/c, was used to address findings in the PPI literature on species and mouse strain differences that question the usefulness of PPI as a cross-species preclinical test. Although the full 5-HT(1A) receptor agonist, 8-OH-DPAT, induced markedly different strain-specific responses in PPI, other selective 5-HT(1A) receptor ligands with partial agonist or antagonist activity elicited similar effects across strains. Pretreatment with the serotonin precursor, 5-HTP, to increase serotonergic activity in the brain, unmasked a decrease in PPI caused by 8-OH-DPAT in C57Bl/6 mice. Pretreatment with the serotonin synthesis inhibitor, PCPA, to decrease serotonergic activity in the brain, unmasked an 8-OH-DPAT-induced increase in PPI in this strain. These studies show that the strain-dependent involvement of 5-HT(1A) receptors in PPI can be modulated by the type of 5-HT(1A) ligand used, or increasing or decreasing serotonin levels in the brain. These results help to clarify some of the mouse strain and species differences in PPI regulation and strengthen its usefulness as a cross-species measure of sensorimotor gating.
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Affiliation(s)
- Maarten van den Buuse
- Behavioural Neuroscience Laboratory,
Mental Health Research Institute, Florey Institute for Neuroscience
and Mental Health, Kenneth Myer Building, and Department of Pharmacology, University of Melbourne, Melbourne, Australia
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12
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Modafinil disrupts prepulse inhibition in mice: Strain differences and involvement of dopaminergic and serotonergic activation. Eur J Pharmacol 2013; 699:132-40. [DOI: 10.1016/j.ejphar.2012.11.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 11/15/2012] [Accepted: 11/23/2012] [Indexed: 11/21/2022]
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13
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Long-term behavioral and NMDA receptor effects of young-adult corticosterone treatment in BDNF heterozygous mice. Neurobiol Dis 2012; 46:722-31. [PMID: 22426399 DOI: 10.1016/j.nbd.2012.03.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 02/07/2012] [Accepted: 03/01/2012] [Indexed: 12/27/2022] Open
Abstract
Psychiatric illnesses, such as schizophrenia, are most likely caused by an interaction between genetic predisposition and environmental factors, including stress during development. The neurotrophin, brain-derived neurotrophic factor (BDNF) has been implicated in this illness as BDNF levels are decreased in the brain of patients with schizophrenia. The aim of the present study was to assess the combined effect of reduced BDNF levels and postnatal stress, simulated by chronic young-adult treatment with the stress hormone, corticosterone. From 6 weeks of age, female and male BDNF heterozygous mice and their wild-type controls were chronically treated with corticosterone in their drinking water for 3 weeks. At 11 weeks of age, male, but not female BDNF heterozygous mice treated with corticosterone exhibited a profound memory deficit in the Y-maze. There were no differences between the groups in baseline prepulse inhibition (PPI), a measure of sensorimotor gating, or its disruption by treatment with MK-801. However, an increase in startle caused by MK-801 treatment was absent in male, but not female BDNF heterozygous mice, irrespective of corticosterone treatment. Analysis of protein levels of the NMDA receptor subunits NR1, NR2A, NR2B and NR2C, showed a marked increase of NR2B levels in the dorsal hippocampus of male BDNF heterozygous mice treated with corticosterone. In the ventral hippocampus, significantly reduced levels of NR2A, NR2B and NR2C were observed in male BDNF heterozygous mice. The NMDA receptor effects in hippocampal sub-regions could be related to the spatial memory deficits and the loss of the effect of MK-801 on startle in these mice, respectively. No significant changes in NMDA receptor subunit levels were observed in any of the female groups. Similarly, no significant changes in levels of BDNF or its receptor, TrkB, were found other than the expected reduced levels of BDNF in heterozygous mice. In conclusion, the data show differential interactive effects of reduced levels of BDNF expression and corticosterone treatment on spatial memory and startle in male and female mice, accompanied by significant, but region-specific changes in NMDA receptor subunit levels in the dorsal and ventral hippocampus. These results could be important for our understanding of the interaction of neurodevelopmental stress and BDNF deficiency in cognitive and anxiety-related symptoms of psychiatric illnesses, such as schizophrenia.
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Zhang LL, Wang JJ, Liu Y, Lu XB, Kuang Y, Wan YH, Chen Y, Yan HM, Fei J, Wang ZG. GPR26-deficient mice display increased anxiety- and depression-like behaviors accompanied by reduced phosphorylated cyclic AMP responsive element-binding protein level in central amygdala. Neuroscience 2011; 196:203-14. [DOI: 10.1016/j.neuroscience.2011.08.069] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 08/21/2011] [Accepted: 08/31/2011] [Indexed: 01/27/2023]
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15
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Expression of Gαz in C2C12 cells restrains myogenic differentiation. Cell Signal 2011; 23:389-97. [DOI: 10.1016/j.cellsig.2010.10.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 09/16/2010] [Accepted: 10/01/2010] [Indexed: 10/19/2022]
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van den Buuse M. Modeling the positive symptoms of schizophrenia in genetically modified mice: pharmacology and methodology aspects. Schizophr Bull 2010; 36:246-70. [PMID: 19900963 PMCID: PMC2833124 DOI: 10.1093/schbul/sbp132] [Citation(s) in RCA: 268] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In recent years, there have been huge advances in the use of genetically modified mice to study pathophysiological mechanisms involved in schizophrenia. This has allowed rapid progress in our understanding of the role of several proposed gene mechanisms in schizophrenia, and yet this research has also revealed how much still remains unresolved. Behavioral studies in genetically modified mice are reviewed with special emphasis on modeling psychotic-like behavior. I will particularly focus on observations on locomotor hyperactivity and disruptions of prepulse inhibition (PPI). Recommendations are included to address pharmacological and methodological aspects in future studies. Mouse models of dopaminergic and glutamatergic dysfunction are then discussed, reflecting the most important and widely studied neurotransmitter systems in schizophrenia. Subsequently, psychosis-like behavior in mice with modifications in the most widely studied schizophrenia susceptibility genes is reviewed. Taken together, the available studies reveal a wealth of available data which have already provided crucial new insight and mechanistic clues which could lead to new treatments or even prevention strategies for schizophrenia.
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Affiliation(s)
- Maarten van den Buuse
- Mental Health Research Institute of Victoria, Parkville, Melbourne, Victoria 3052, Australia.
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Hill RA, Murray SS, Halley PG, Binder MD, Martin SJ, van den Buuse M. Brain-derived neurotrophic factor expression is increased in the hippocampus of 5-HT2C receptor knockout mice. Hippocampus 2010; 21:434-45. [DOI: 10.1002/hipo.20759] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Boon WC, van den Buuse M, Wegener N, Martin S, Chua HK, Bush AI, Masters CL, Adlard PA, Li QX. Behavioural phenotype of APPC100.V717F transgenic mice over-expressing a mutant Abeta-bearing fragment is associated with reduced NMDA receptor density. Behav Brain Res 2010; 209:27-35. [PMID: 20085783 DOI: 10.1016/j.bbr.2010.01.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 01/07/2010] [Accepted: 01/09/2010] [Indexed: 11/25/2022]
Abstract
The aim of this study was to characterize APPC100.V717F transgenic (TgC100.V717F) mice which over-express a mutant C100 fragment of the amyloid precursor protein. The mice were compared to TgC100 wild type mice (TgC100.WT) and non-transgenic controls at 4-9 and 16-22 months of age. TgC100.V717F mice showed behavioural hyperactivity, particularly at a younger age, as shown by increased numbers of elevated plus maze arm entries and Y-maze arm entries, enhanced baseline locomotor activity in the open field, and enhanced amphetamine-induced hyperlocomotion. This hyperactivity was less pronounced in TgC100.WT which only displayed significant differences to non-transgenic controls at a younger age for the number of Y-maze arm entries and baseline locomotor activity in the open field. In addition, TgC100.V717F mice, but not TgC100.WT, demonstrated cognitive deficits, as shown by reduced spontaneous alternation in the Y-maze and markedly reduced retention in a passive avoidance test. At an older age, TgC100.V717F mice showed enhanced startle and increased immobility time in the forced swim test. In the TgC100.V717F mice, but not TgC100.WT, the behavioural changes were paralleled by a significant reduction in the expression of hippocampal NMDA receptor subunits types 1 and 2A. Concomitantly, we detected axonal disruption and apoptosis in the hippocampus of TgC100.V717F mice. In conclusion, these data demonstrate that the mutant C100 fragment is an effector of biochemical and both cognitive and non-cognitive behaviours. These transgenic mice may be a model for the psychotic features associated with early Alzheimer's disease.
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Role of serotonin-1A receptors in the action of antipsychotic drugs: comparison of prepulse inhibition studies in mice and rats and relevance for human pharmacology. Behav Pharmacol 2008; 19:548-61. [PMID: 18690109 DOI: 10.1097/fbp.0b013e32830cd822] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study aimed to explore strain and species differences in the involvement of 5-HT1A receptors in the action of antipsychotic drugs, using prepulse inhibition (PPI), a model of sensory processing which is deficient in schizophrenia patients. We used automated startle boxes to compare the effect of the 5-HT1A receptor agonist, (+/-)-8-hydroxy-dipropyl-amino-tetralin (8-OH-DPAT), on PPI in three mouse strains. Balb/c mice were then pretreated with antipsychotics, treated with 8-OH-DPAT or saline, and tested for PPI. 8-OH-DPAT treatment dose dependently increased PPI in Balb/c mice, but had less effect in 129Sv and C57Bl/6 mice. In Balb/c mice, the effect of 8-OH-DPAT was blocked by the typical antipsychotic and dopamine D2 receptor antagonist, haloperidol and the third generation antipsychotic, aripiprazole, which has activity at both 5-HT1A and dopamine D2 receptors. The atypical antipsychotics, clozapine, olanzapine and risperidone, had lesser effects. Similar to our earlier studies in rats, the present PPI results suggest that 5-HT1A receptors are involved in the action of some antipsychotic drugs in mice. Despite strain and species differences in the magnitude and direction of the effect of 8-OH-DPAT, downstream dopamine D2 receptor activation seems to be an important mediator. These comparative results allow a theoretical framework of receptor interactions, which may guide further studies on the involvement of 5-HT1A receptors in schizophrenia.
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Abstract
The search for liability genes of the world's 2 major psychotic disorders, schizophrenia and bipolar disorder I (BP-I), has been extremely difficult even though evidence suggests that both are highly heritable. This difficulty is due to the complex and multifactorial nature of these disorders. They encompass several intermediate phenotypes, some overlapping across the 2 psychotic disorders that jointly and/or interactively produce the clinical manifestations. Research of the past few decades has identified several neurophysiological deficits in schizophrenia that frequently occur before the onset of psychosis. These include abnormalities in smooth pursuit eye movements, P50 sensory gating, prepulse inhibition, P300, mismatch negativity, and neural synchrony. Evidence suggests that many of these physiological deficits are distinct from each other. They are stable, mostly independent of symptom state and medications (with some exceptions) and are also observed in non-ill relatives. This suggests a familial and perhaps genetic nature. Some deficits are also observed in the BP-I probands and to a lesser extent their relatives. These deficits in physiological measures may represent the intermediate phenotypes that index small effects of genes (and/or environmental factors). The use of these measures in genetic studies may help the hunt for psychosis liability genes and clarify the extent to which the 2 major psychotic disorders share etio-pathophysiology. In spite of the rich body of work describing these neurophysiological measures in psychotic disorders, challenges remain: Many of the neurophysiological phenotypes are still relatively complex and are associated with low heritability estimates. Further refinement of these physiological phenotypes is needed that could identify specific underlying physiological deficits and thereby improve their heritability estimates. The extent to which these neurophysiological deficits are unique or overlap across BP-I and schizophrenia is unclear. And finally, the clinical and functional consequences of the neurophysiological deficits both in the probands and their relatives are not well described.
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Affiliation(s)
- Gunvant K. Thaker
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, PO Box 21247, Baltimore, MD 21228,To whom correspondence should be addressed; tel: 410-402-6821; fax: 410-402-6021; e-mail:
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Phencyclidine-induced locomotor hyperactivity is enhanced in mice after stereotaxic brain serotonin depletion. Behav Brain Res 2008; 191:289-93. [PMID: 18482774 DOI: 10.1016/j.bbr.2008.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 04/04/2008] [Accepted: 04/07/2008] [Indexed: 11/23/2022]
Abstract
The aim of this study was to investigate the role of forebrain serotonin projections in behavioural models with relevance to schizophrenia. Mice received stereotaxic micro-injections of the serotonin neurotoxin 5,7-dihydroxytryptamine into the median raphe nucleus (MRN). Two weeks later, MRN-lesioned mice were hyperactive at baseline and showed enhanced locomotor hyperactivity induced by phencyclidine. In contrast, no lesion effect was observed on the locomotor hyperactivity induced by amphetamine treatment or on prepulse inhibition. Lesioned mice showed a 68% depletion of serotonin in the hippocampus and 31% depletion in the striatum. These data confirm previous studies in rats that selective serotonin depletion in the brain enhances the effect of phencyclidine, but not amphetamine, on locomotor activity. This enhanced action of phencyclidine is likely to be mediated by the absence of serotonin-mediated behavioural inhibition in the hippocampus, leaving the psychostimulant effects of phencyclidine unopposed. Taken together with previous studies in rats, these studies in mice suggest that serotonin release in the dorsal hippocampus constitutes a behavioural inhibitory pathway normally involved in dampening excessive behavioural stimulation. Dysfunction of this pathway could be involved in psychosis and its stimulation could be a potential mechanism of action of antipsychotic drugs.
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George S, van den Buuse M, San Mok S, Masters CL, Li QX, Culvenor JG. α-Synuclein transgenic mice exhibit reduced anxiety-like behaviour. Exp Neurol 2008; 210:788-92. [DOI: 10.1016/j.expneurol.2007.12.017] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 12/07/2007] [Accepted: 12/15/2007] [Indexed: 12/30/2022]
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