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Pelletier OB, Brunori G, Wang Y, Robishaw JD. Post-transcriptional regulation and subcellular localization of G-protein γ7 subunit: implications for striatal function and behavioral responses to cocaine. Front Neuroanat 2024; 18:1394659. [PMID: 38764487 PMCID: PMC11100332 DOI: 10.3389/fnana.2024.1394659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 04/17/2024] [Indexed: 05/21/2024] Open
Abstract
The striatal D1 dopamine receptor (D1R) and A2a adenosine receptor (A2aR) signaling pathways play important roles in drug-related behaviors. These receptors activate the Golf protein comprised of a specific combination of αolfβ2γ7 subunits. During assembly, the γ7 subunit sets the cellular level of the Golf protein. In turn, the amount of Golf protein determines the collective output from both D1R and A2aR signaling pathways. This study shows the Gng7 gene encodes multiple γ7 transcripts differing only in their non-coding regions. In striatum, Transcript 1 is the predominant isoform. Preferentially expressed in the neuropil, Transcript 1 is localized in dendrites where it undergoes post-transcriptional regulation mediated by regulatory elements in its 3' untranslated region that contribute to translational suppression of the γ7 protein. Earlier studies on gene-targeted mice demonstrated loss of γ7 protein disrupts assembly of the Golf protein. In the current study, morphological analysis reveals the loss of the Golf protein is associated with altered dendritic morphology of medium spiny neurons. Finally, behavioral analysis of conditional knockout mice with cell-specific deletion of the γ7 protein in distinct populations of medium spiny neurons reveals differential roles of the Golf protein in mediating behavioral responses to cocaine. Altogether, these findings provide a better understanding of the regulation of γ7 protein expression, its impact on Golf function, and point to a new potential target and mechanisms for treating addiction and related disorders.
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Affiliation(s)
- Oliver B. Pelletier
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Gloria Brunori
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Yingcai Wang
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Janet D. Robishaw
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
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2
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Selective Manipulation of G-Protein γ 7 Subunit in Mice Provides New Insights into Striatal Control of Motor Behavior. J Neurosci 2021; 41:9065-9081. [PMID: 34544837 DOI: 10.1523/jneurosci.1211-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/26/2021] [Accepted: 09/11/2021] [Indexed: 01/15/2023] Open
Abstract
Stimulatory coupling of dopamine D1 (D1R) and adenosine A2A receptors (A2AR) to adenylyl cyclase within the striatum is mediated through a specific Gαolfβ2γ7 heterotrimer to ultimately modulate motor behaviors. To dissect the individual roles of the Gαolfβ2γ7 heterotrimer in different populations of medium spiny neurons (MSNs), we produced and characterized conditional mouse models, in which the Gng7 gene was deleted in either the D1R- or A2AR/D2R-expressing MSNs. We show that conditional loss of γ7 disrupts the cell type-specific assembly of the Gαolfβ2γ7 heterotrimer, thereby identifying its circumscribed roles acting downstream of either the D1Rs or A2ARs in coordinating motor behaviors, including in vivo responses to psychostimulants. We reveal that Gαolfβ2γ7/cAMP signal in D1R-MSNs does not impact spontaneous and amphetamine-induced locomotor behaviors in male and female mice, while its loss in A2AR/D2R-MSNs results in a hyperlocomotor phenotype and enhanced locomotor response to amphetamine. Additionally, Gαolfβ2γ7/cAMP signal in either D1R- or A2AR/D2R-expressing MSNs is not required for the activation of PKA signaling by amphetamine. Finally, we show that Gαolfβ2γ7 signaling acting downstream of D1Rs is selectively implicated in the acute locomotor-enhancing effects of morphine. Collectively, these results support the general notion that receptors use specific Gαβγ proteins to direct the fidelity of downstream signaling pathways and to elicit a diverse repertoire of cellular functions. Specifically, these findings highlight the critical role for the γ7 protein in determining the cellular level, and hence, the function of the Gαolfβ2γ7 heterotrimer in several disease states associated with dysfunctional striatal signaling.SIGNIFICANCE STATEMENT Dysfunction or imbalance of cAMP signaling in the striatum has been linked to several neurologic and neuropsychiatric disorders, including Parkinson's disease, dystonia, schizophrenia, and drug addiction. By genetically targeting the γ7 subunit in distinct striatal neuronal subpopulations in mice, we demonstrate that the formation and function of the Gαolfβ2γ7 heterotrimer, which represents the rate-limiting step for cAMP production in the striatum, is selectively disrupted. Furthermore, we reveal cell type-specific roles for Gαolfβ2γ7-mediated cAMP production in the control of spontaneous locomotion as well as behavioral and molecular responses to psychostimulants. Our findings identify the γ7 protein as a novel therapeutic target for disease states associated with dysfunctional striatal cAMP signaling.
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Abstract
To form synaptic connections and store information, neurons continuously remodel their proteomes. The impressive length of dendrites and axons imposes logistical challenges to maintain synaptic proteins at locations remote from the transcription source (the nucleus). The discovery of thousands of messenger RNAs (mRNAs) near synapses suggested that neurons overcome distance and gain autonomy by producing proteins locally. It is not generally known, however, if, how, and when localized mRNAs are translated into protein. To investigate the translational landscape in neuronal subregions, we performed simultaneous RNA sequencing (RNA-seq) and ribosome sequencing (Ribo-seq) from microdissected rodent brain slices to identify and quantify the transcriptome and translatome in cell bodies (somata) as well as dendrites and axons (neuropil). Thousands of transcripts were differentially translated between somatic and synaptic regions, with many scaffold and signaling molecules displaying increased translation levels in the neuropil. Most translational changes between compartments could be accounted for by differences in RNA abundance. Pervasive translational regulation was observed in both somata and neuropil influenced by specific mRNA features (e.g., untranslated region [UTR] length, RNA-binding protein [RBP] motifs, and upstream open reading frames [uORFs]). For over 800 mRNAs, the dominant source of translation was the neuropil. We constructed a searchable and interactive database for exploring mRNA transcripts and their translation levels in the somata and neuropil [MPI Brain Research, The mRNA translation landscape in the synaptic neuropil. https://public.brain.mpg.de/dashapps/localseq/ Accessed 5 October 2021]. Overall, our findings emphasize the substantial contribution of local translation to maintaining synaptic protein levels and indicate that on-site translational control is an important mechanism to control synaptic strength.
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Crittenden JR, Gipson TA, Smith AC, Bowden HA, Yildirim F, Fischer KB, Yim M, Housman DE, Graybiel AM. Striatal transcriptome changes linked to drug-induced repetitive behaviors. Eur J Neurosci 2021; 53:2450-2468. [PMID: 33759265 DOI: 10.1111/ejn.15116] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/23/2020] [Accepted: 01/09/2021] [Indexed: 11/30/2022]
Abstract
Disruptive or excessive repetitive motor patterns (stereotypies) are cardinal symptoms in numerous neuropsychiatric disorders. Stereotypies are also evoked by psychomotor stimulants such as amphetamine. The acquisition of motor sequences is paralleled by changes in activity patterns in the striatum, and stereotypies have been linked to abnormal plasticity in these reinforcement-related circuits. Here, we designed experiments in mice to identify transcriptomic changes that underlie striatal plasticity occurring alongside the development of drug-induced stereotypic behavior. We identified three schedules of amphetamine treatment inducing different degrees of stereotypy and used bulk RNAseq to compare striatal gene expression changes among groups of mice treated with the different drug-dose schedules and vehicle-treated, cage-mate controls. Mice were identified as naïve, sensitized, or tolerant to drug-induced stereotypy. All drug-treated groups exhibited expression changes in genes that encode members of the extracellular signal-regulated kinase (ERK) cascades known to regulate psychomotor stimulant responses. In the sensitized group with the most prolonged stereotypy, we found dysregulation of 20 genes that were not changed in other groups. Gene set enrichment analysis indicated highly significant overlap with genes regulated by neuregulin 1 (Nrg1). Nrg1 is known to be a schizophrenia and autism susceptibility gene that encodes a ligand for Erb-B receptors, which are involved in neuronal migration, myelination, and cell survival, including that of dopamine-containing neurons. Stimulant abuse is a risk factor for schizophrenia onset, and these two disorders share behavioral stereotypy phenotypes. Our results raise the possibility that drug-induced sensitization of the Nrg1 signaling pathway might underlie these links.
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Affiliation(s)
- Jill R Crittenden
- McGovern Institute for Brain Research, The Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Brain and Cognitive Sciences, The Massachusetts Institute of Technology, Cambridge, MA, USA.,Institute for Integrative Cancer Research, The Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Theresa A Gipson
- Institute for Integrative Cancer Research, The Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Anne C Smith
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, USA
| | - Hilary A Bowden
- McGovern Institute for Brain Research, The Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Brain and Cognitive Sciences, The Massachusetts Institute of Technology, Cambridge, MA, USA.,Institute for Integrative Cancer Research, The Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ferah Yildirim
- Department of Neuropsychiatry, Department of Psychiatry and Psychotherapy, and NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Kyle B Fischer
- McGovern Institute for Brain Research, The Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Brain and Cognitive Sciences, The Massachusetts Institute of Technology, Cambridge, MA, USA.,Institute for Integrative Cancer Research, The Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Michael Yim
- McGovern Institute for Brain Research, The Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Brain and Cognitive Sciences, The Massachusetts Institute of Technology, Cambridge, MA, USA
| | - David E Housman
- Institute for Integrative Cancer Research, The Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ann M Graybiel
- McGovern Institute for Brain Research, The Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Brain and Cognitive Sciences, The Massachusetts Institute of Technology, Cambridge, MA, USA
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Abstract
Although historically research has focused on transcription as the central governor of protein expression, protein translation is now increasingly being recognized as a major factor for determining protein levels within cells. The central nervous system relies on efficient updating of the protein landscape. Thus, coordinated regulation of mRNA localization, initiation, or termination of translation is essential for proper brain function. In particular, dendritic protein synthesis plays a key role in synaptic plasticity underlying learning and memory as well as cognitive processes. Increasing evidence suggests that impaired mRNA translation is a common feature found in numerous psychiatric disorders. In this review, we describe how malfunction of translation contributes to development of psychiatric diseases, including schizophrenia, major depression, bipolar disorder, and addiction.
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Affiliation(s)
- Sophie Laguesse
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA.,GIGA-Neurosciences, GIGA-Stem Cells, University of Liège, Liège, Belgium
| | - Dorit Ron
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
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Goncalves TM, Southey BR, Rodriguez-Zas SL. Interplay Between Amphetamine and Activity Level in Gene Networks of the Mouse Striatum. Bioinform Biol Insights 2018; 12:1177932218815152. [PMID: 30559594 PMCID: PMC6291885 DOI: 10.1177/1177932218815152] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 10/18/2018] [Indexed: 01/09/2023] Open
Abstract
The psychostimulant amphetamine can be prescribed to ameliorate the symptoms of narcolepsy, attention-deficit hyperactivity disorder and to facilitate weight loss. This stimulant can also have negative effects including toxicity and addiction risk. The impact of amphetamine on gene networks is partially understood and this study addresses this gap in consideration of the physical activity. The striata of mice exposed to either amphetamine or saline treatment were compared in a mouse line selected for home cage physical overactivity, a phenotype that can be mitigated with amphetamine, and in a contemporary control line using RNA-seq. Genes presenting opposite expression patterns between treatments across lines included a pseudogene of coiled-coil-helix-coiled-coil-helix domain containing 2 gene (Chchd2), ribonuclease P RNA component H1 (Rpph1), short stature homeobox 2 (Shox2), transient receptor potential melastatin 6 (Trpm6), and tumor necrosis factor receptor superfamily, member 9 (Tnfrsf9). Genes presenting consistent treatment patterns across lines, albeit at different levels of significance included cholecystokinin (Cck), vasoactive intestinal polypeptide (Vip), arginine vasopressin (Avp), oxytocin/neurophysin (Oxt), thyrotropin releasing hormone (Trh), neurotensin (Nts), angiotensinogen (Agt), galanin (Gal), prolactin receptor (Prlr), and calcitonin receptor (Calcr). Potassium inwardly rectifying channel, subfamily J, member 6 (Kcnj6), and retinoic acid-related (RAR)-related orphan receptor alpha (Rora) were similarly differentially expressed between treatments across lines. Functional categories enriched among the genes presenting line-dependent amphetamine effect included genes coding for neuropeptides and associated with memory and neuroplasticity and synaptic signaling, energy, and redox processes. A line-dependent association between amphetamine exposure and the synaptic signaling genes neurogranin (Nrgn) and synaptic membrane exocytosis 1(Rims1) was highlighted in the gene networks. Our findings advance the understanding of molecular players and networks affected by amphetamine in support of the development of activity-targeted therapies that may capitalize on the benefits of this psychostimulant.
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Affiliation(s)
- Tassia M Goncalves
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Bruce R Southey
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Sandra L Rodriguez-Zas
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Statistics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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Kinases of eIF2a Switch Translation of mRNA Subset during Neuronal Plasticity. Int J Mol Sci 2017; 18:ijms18102213. [PMID: 29065505 PMCID: PMC5666893 DOI: 10.3390/ijms18102213] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/18/2017] [Accepted: 10/19/2017] [Indexed: 12/31/2022] Open
Abstract
Compared to other types of cells, neurons express the largest number of diverse mRNAs, including neuron-specific ones. This mRNA diversity is required for neuronal function, memory storage, maintenance and retrieval. Regulation of translation in neurons is very complicated and involves various proteins. Some proteins, implementing translational control in other cell types, are used by neurons for synaptic plasticity. In this review, we discuss the neuron-specific activity of four kinases: protein kinase R (PKR), PKR-like endoplasmic reticulum kinase (PERK), general control nonderepressible 2 kinase (GCN2), and heme-reguated eIF2α kinase (HRI), the substrate for which is α-subunit of eukaryotic initiation factor 2 (eIF2α). Phosphorylation of eIF2α is necessary for the cell during stress conditions, such as lack of amino acids, energy stress or viral infection. We propose that, during memory formation, neurons use some mechanisms similar to those involved in the cellular stress. The four eIF2α kinases regulate translation of certain mRNAs containing upstream open reading frames (uORFs). These mRNAs encode proteins involved in the processes of long-term potentiation (LTP) or long-term depression (LTD). The review examines some neuronal proteins for which translation regulation by eIF2 was suggested and checked experimentally. Of such proteins, we pay close attention to protein kinase Mζ, which is involved in memory storage and regulated at the translational level.
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Managò F, Papaleo F. Schizophrenia: What's Arc Got to Do with It? Front Behav Neurosci 2017; 11:181. [PMID: 28979198 PMCID: PMC5611489 DOI: 10.3389/fnbeh.2017.00181] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 09/11/2017] [Indexed: 01/08/2023] Open
Abstract
Human studies of schizophrenia are now reporting a previously unidentified genetic convergence on postsynaptic signaling complexes such as the activity-regulated cytoskeletal-associated (Arc) gene. However, because this evidence is still very recent, the neurobiological implication of Arc in schizophrenia is still scattered and unrecognized. Here, we first review current and developing findings connecting Arc in schizophrenia. We then highlight recent and previous findings from preclinical mouse models that elucidate how Arc genetic modifications might recapitulate schizophrenia-relevant behavioral phenotypes following the novel Research Domain Criteria (RDoC) framework. Building on this, we finally compare and evaluate several lines of evidence demonstrating that Arc genetics can alter both glutamatergic and dopaminergic systems in a very selective way, again consistent with molecular alterations characteristic of schizophrenia. Despite being only initial, accumulating and compelling data are showing that Arc might be one of the primary biological players in schizophrenia. Synaptic plasticity alterations in the genetic architecture of psychiatric disorders might be a rule, not an exception. Thus, we anticipate that additional evidence will soon emerge to clarify the Arc-dependent mechanisms involved in the psychiatric-related dysfunctional behavior.
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Affiliation(s)
- Francesca Managò
- Department of Neuroscience and Brain Technologies, Istituto Italiano di TecnologiaGenova, Italy
| | - Francesco Papaleo
- Department of Neuroscience and Brain Technologies, Istituto Italiano di TecnologiaGenova, Italy
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Glutamate-Dependent Translational Control of Glutamine Synthetase in Bergmann Glia Cells. Mol Neurobiol 2017; 55:5202-5209. [PMID: 28875233 DOI: 10.1007/s12035-017-0756-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/24/2017] [Indexed: 12/12/2022]
Abstract
Glutamate is the major excitatory transmitter of the vertebrate brain. It exerts its actions through the activation of specific plasma membrane receptors expressed both in neurons and in glial cells. Recent evidence has shown that glutamate uptake systems, particularly enriched in glia cells, trigger biochemical cascades in a similar fashion as receptors. A tight regulation of glutamate extracellular levels prevents neuronal overstimulation and cell death, and it is critically involved in glutamate turnover. Glial glutamate transporters are responsible of the majority of the brain glutamate uptake activity. Once internalized, this excitatory amino acid is rapidly metabolized to glutamine via the astrocyte-enriched enzyme glutamine synthetase. A coupling between glutamate uptake and glutamine synthesis and release has been commonly known as the glutamate/glutamine shuttle. Taking advantage of the established model of cultured Bergmann glia cells, in this contribution, we explored the gene expression regulation of glutamine synthetase. A time- and dose-dependent regulation of glutamine synthetase protein and activity levels was found. Moreover, glutamate exposure resulted in the transient shift of glutamine synthetase mRNA from the monosomal to the polysomal fraction. These results demonstrate a novel mode of glutamate-dependent glutamine synthetase regulation and strengthen the notion of an exquisite glia neuronal interaction in glutamatergic synapses.
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