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Wang P, Miller KK, He E, Dhawan SS, Cunningham CL, Grillet N. LOXHD1 is indispensable for maintaining TMC1 auditory mechanosensitive channels at the site of force transmission. Nat Commun 2024; 15:7865. [PMID: 39256406 PMCID: PMC11387651 DOI: 10.1038/s41467-024-51850-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 08/20/2024] [Indexed: 09/12/2024] Open
Abstract
Hair cell bundles consist of stereocilia arranged in rows of increasing heights, connected by tip links that transmit sound-induced forces to shorter stereocilia tips. Auditory mechanotransduction channel complexes, composed of proteins TMC1/2, TMIE, CIB2, and LHFPL5, are located at the tips of shorter stereocilia. While most components can interact with the tip link in vitro, their ability to maintain the channel complexes at the tip link in vivo is uncertain. Return, using mouse models, we show that an additional component, LOXHD1, is essential for keeping TMC1-pore forming subunits at the tip link but is dispensable for TMC2. Using SUB-immunogold-SEM, we showed that TMC1 localizes near the tip link but mislocalizes without LOXHD1. LOXHD1 selectively interacts with TMC1, CIB2, LHFPL5, and tip-link protein PCDH15. Our results demonstrate that TMC1-driven mature auditory channels require LOXHD1 to stay connected to the tip link and remain functional, while TMC2-driven developmental channels do not.
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Affiliation(s)
- Pei Wang
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Katharine K Miller
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Enqi He
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Siddhant S Dhawan
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Christopher L Cunningham
- Pittsburgh Hearing Research Center, Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Nicolas Grillet
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA.
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Wang P, Miller KK, He E, Dhawan SS, Cunningham CL, Grillet N. LOXHD1 is indispensable for coupling auditory mechanosensitive channels to the site of force transmission. RESEARCH SQUARE 2024:rs.3.rs-3752492. [PMID: 38260480 PMCID: PMC10802736 DOI: 10.21203/rs.3.rs-3752492/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Hearing is initiated in hair cells by the mechanical activation of ion channels in the hair bundle. The hair bundle is formed by stereocilia organized into rows of increasing heights interconnected by tip links, which convey sound-induced forces to stereocilia tips. The auditory mechanosensitive channels are complexes containing at least four protein-subunits - TMC1/2, TMIE, CIB2, and LHFPL51-16 - and are located at the tips of shorter stereocilia at a yet-undetermined distance from the lower tip link insertion point17. While multiple auditory channel subunits appear to interact with the tip link, it remains unknown whether their combined interaction alone can resist the high-frequency mechanical stimulations owing to sound. Here we show that an unanticipated additional element, LOXHD1, is indispensable for maintaining the TMC1 pore-forming channel subunits coupled to the tip link. We demonstrate that LOXHD1 is a unique element of the auditory mechanotransduction complex that selectively affects the localization of TMC1, but not its close developmental paralogue TMC2. Taking advantage of our novel immunogold scanning electron microscopy method for submembranous epitopes (SUB-immunogold-SEM), we demonstrate that TMC1 normally concentrates within 100-nm of the tip link insertion point. In LOXHD1's absence, TMC1 is instead mislocalized away from this force transmission site. Supporting this finding, we found that LOXHD1 interacts selectively in vitro with TMC1 but not with TMC2 while also binding to channel subunits CIB2 and LHFPL5 and tip-link protein PCDH15. SUB-immunogold-SEM additionally demonstrates that LOXHD1 and TMC1 are physically connected to the lower tip-link complex in situ. Our results show that the TMC1-driven mature channels require LOXHD1 to stay coupled to the tip link and remain functional, but the TMC2-driven developmental channels do not. As both tip links and TMC1 remain present in hair bundles lacking LOXHD1, it opens the possibility to reconnect them and restore hearing for this form of genetic deafness.
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Affiliation(s)
- Pei Wang
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Katharine K. Miller
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Enqi He
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Siddhant S. Dhawan
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Christopher L. Cunningham
- Pittsburgh Hearing Research Center, Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Nicolas Grillet
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
- Lead contact
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RGS4 RNA Secondary Structure Mediates Staufen2 RNP Assembly in Neurons. Int J Mol Sci 2021; 22:ijms222313021. [PMID: 34884825 PMCID: PMC8657808 DOI: 10.3390/ijms222313021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 11/26/2022] Open
Abstract
RNA-binding proteins (RBPs) act as posttranscriptional regulators controlling the fate of target mRNAs. Unraveling how RNAs are recognized by RBPs and in turn are assembled into neuronal RNA granules is therefore key to understanding the underlying mechanism. While RNA sequence elements have been extensively characterized, the functional impact of RNA secondary structures is only recently being explored. Here, we show that Staufen2 binds complex, long-ranged RNA hairpins in the 3′-untranslated region (UTR) of its targets. These structures are involved in the assembly of Staufen2 into RNA granules. Furthermore, we provide direct evidence that a defined Rgs4 RNA duplex regulates Staufen2-dependent RNA localization to distal dendrites. Importantly, disrupting the RNA hairpin impairs the observed effects. Finally, we show that these secondary structures differently affect protein expression in neurons. In conclusion, our data reveal the importance of RNA secondary structure in regulating RNA granule assembly, localization and eventually translation. It is therefore tempting to speculate that secondary structures represent an important code for cells to control the intracellular fate of their mRNAs.
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Rgs4 is a regulator of mTOR activity required for motoneuron axon outgrowth and neuronal development in zebrafish. Sci Rep 2021; 11:13338. [PMID: 34172795 PMCID: PMC8233358 DOI: 10.1038/s41598-021-92758-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 06/15/2021] [Indexed: 12/21/2022] Open
Abstract
The Regulator of G protein signaling 4 (Rgs4) is a member of the RGS proteins superfamily that modulates the activity of G-protein coupled receptors. It is mainly expressed in the nervous system and is linked to several neuronal signaling pathways; however, its role in neural development in vivo remains inconclusive. Here, we generated and characterized a rgs4 loss of function model (MZrgs4) in zebrafish. MZrgs4 embryos showed motility defects and presented reduced head and eye sizes, reflecting defective motoneurons axon outgrowth and a significant decrease in the number of neurons in the central and peripheral nervous system. Forcing the expression of Rgs4 specifically within motoneurons rescued their early defective outgrowth in MZrgs4 embryos, indicating an autonomous role for Rgs4 in motoneurons. We also analyzed the role of Akt, Erk and mechanistic target of rapamycin (mTOR) signaling cascades and showed a requirement for these pathways in motoneurons axon outgrowth and neuronal development. Drawing on pharmacological and rescue experiments in MZrgs4, we provide evidence that Rgs4 facilitates signaling mediated by Akt, Erk and mTOR in order to drive axon outgrowth in motoneurons and regulate neuronal numbers.
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5
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Bouchet CA, McPherson KB, Li MH, Traynor JR, Ingram SL. Mice Expressing Regulators of G protein Signaling-insensitive Gαo Define Roles of μ Opioid Receptor G αo and G αi Subunit Coupling in Inhibition of Presynaptic GABA Release. Mol Pharmacol 2021; 100:217-223. [PMID: 34135098 DOI: 10.1124/molpharm.121.000249] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 06/04/2021] [Indexed: 11/22/2022] Open
Abstract
Regulators of G protein signaling (RGS) proteins modulate signaling by G protein-coupled receptors. Using a knock-in transgenic mouse model with a mutation in Gαo that does not bind RGS proteins (RGS-insensitive), we determined the effect of RGS proteins on presynaptic μ opioid receptor (MOR)-mediated inhibition of GABA release in the ventrolateral periaqueductal gray (vlPAG). The MOR agonists [d-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO) and met-enkephalin (ME) inhibited evoked inhibitory postsynaptic currents (eIPSCs) in the RGS-insensitive mice compared with wild-type (WT) littermates, respectively. Fentanyl inhibited eIPSCs similarly in both WT and RGS-insensitive mice. There were no differences in opioid agonist inhibition of spontaneous GABA release between the genotypes. To further probe the mechanism underlying these differences between opioid inhibition of evoked and spontaneous GABA release, specific myristoylated Gα peptide inhibitors for Gαo1 and Gαi1-3 that block receptor-G protein interactions were used to test the preference of agonists for MOR-Gα complexes. The Gαo1 inhibitor reduced DAMGO inhibition of eIPSCs, but Gαi1-3 inhibitors had no effect. Both Gαo1 and Gαi1-3 inhibitors separately reduced fentanyl inhibition of eIPSCs but had no effects on ME inhibition. Gαi1-3 inhibitors blocked the inhibitory effects of ME and fentanyl on miniature postsynaptic current (mIPSC) frequency, but both Gαo1 and Gαi1-3 inhibitors were needed to block the effects of DAMGO. Finally, baclofen-mediated inhibition of GABA release is unaffected in the RGS-insensitive mice and in the presence of Gαo1 and Gαi1-3 inhibitor peptides, suggesting that GABAB receptor coupling to G proteins in vlPAG presynaptic terminals is different than MOR coupling. SIGNIFICANCE STATEMENT: Presynaptic μ opioid receptors (MORs) in the ventrolateral periaqueductal gray are critical for opioid analgesia and are negatively regulated by RGS proteins. These data in RGS-insensitive mice provide evidence that MOR agonists differ in preference for Gαo versus Gαi and regulation by RGS proteins in presynaptic terminals, providing a mechanism for functional selectivity between agonists. The results further define important differences in MOR and GABAB receptor coupling to G proteins that could be exploited for new pain therapies.
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Affiliation(s)
- Courtney A Bouchet
- Department of Neurologic Surgery, Oregon Health & Science University, Portland, Oregon (C.A.B., K.B.M., M.L., S.L.I.); and Department of Pharmacology and Edward F. Domino Research Center, Medical School, Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.R.T.)
| | - Kylie B McPherson
- Department of Neurologic Surgery, Oregon Health & Science University, Portland, Oregon (C.A.B., K.B.M., M.L., S.L.I.); and Department of Pharmacology and Edward F. Domino Research Center, Medical School, Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.R.T.)
| | - Ming-Hua Li
- Department of Neurologic Surgery, Oregon Health & Science University, Portland, Oregon (C.A.B., K.B.M., M.L., S.L.I.); and Department of Pharmacology and Edward F. Domino Research Center, Medical School, Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.R.T.)
| | - John R Traynor
- Department of Neurologic Surgery, Oregon Health & Science University, Portland, Oregon (C.A.B., K.B.M., M.L., S.L.I.); and Department of Pharmacology and Edward F. Domino Research Center, Medical School, Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.R.T.)
| | - Susan L Ingram
- Department of Neurologic Surgery, Oregon Health & Science University, Portland, Oregon (C.A.B., K.B.M., M.L., S.L.I.); and Department of Pharmacology and Edward F. Domino Research Center, Medical School, Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.R.T.)
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Senese NB, Kandasamy R, Kochan KE, Traynor JR. Regulator of G-Protein Signaling (RGS) Protein Modulation of Opioid Receptor Signaling as a Potential Target for Pain Management. Front Mol Neurosci 2020; 13:5. [PMID: 32038168 PMCID: PMC6992652 DOI: 10.3389/fnmol.2020.00005] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/09/2020] [Indexed: 12/23/2022] Open
Abstract
Opioid drugs are the gold standard for the management of pain, but their use is severely limited by dangerous and unpleasant side effects. All clinically available opioid analgesics bind to and activate the mu-opioid receptor (MOR), a heterotrimeric G-protein-coupled receptor, to produce analgesia. The activity of these receptors is modulated by a family of intracellular RGS proteins or regulators of G-protein signaling proteins, characterized by the presence of a conserved RGS Homology (RH) domain. These proteins act as negative regulators of G-protein signaling by serving as GTPase accelerating proteins or GAPS to switch off signaling by both the Gα and βγ subunits of heterotrimeric G-proteins. Consequently, knockdown or knockout of RGS protein activity enhances signaling downstream of MOR. In this review we discuss current knowledge of how this activity, across the different families of RGS proteins, modulates MOR activity, as well as activity of other members of the opioid receptor family, and so pain and analgesia in animal models, with particular emphasis on RGS4 and RGS9 families. We discuss inhibition of RGS proteins with small molecule inhibitors that bind to sensitive cysteine moieties in the RH domain and the potential for targeting this family of intracellular proteins as adjuncts to provide an opioid sparing effect or as standalone analgesics by promoting the activity of endogenous opioid peptides. Overall, we conclude that RGS proteins may be a novel drug target to provide analgesia with reduced opioid-like side effects, but that much basic work is needed to define the roles for specific RGS proteins, particularly in chronic pain, as well as a need to develop newer inhibitors.
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Affiliation(s)
- Nicolas B Senese
- Department of Pharmacology, Edward F. Domino Research Center, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Psychiatry, Chicago, IL, United States
| | - Ram Kandasamy
- Department of Pharmacology, Edward F. Domino Research Center, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Psychology, California State University, East Bay, Hayward, CA, United States
| | - Kelsey E Kochan
- Department of Pharmacology, Edward F. Domino Research Center, University of Michigan Medical School, Ann Arbor, MI, United States
| | - John R Traynor
- Department of Pharmacology, Edward F. Domino Research Center, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, United States
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7
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O'Brien JB, Wilkinson JC, Roman DL. Regulator of G-protein signaling (RGS) proteins as drug targets: Progress and future potentials. J Biol Chem 2019; 294:18571-18585. [PMID: 31636120 DOI: 10.1074/jbc.rev119.007060] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) play critical roles in regulating processes such as cellular homeostasis, responses to stimuli, and cell signaling. Accordingly, GPCRs have long served as extraordinarily successful drug targets. It is therefore not surprising that the discovery in the mid-1990s of a family of proteins that regulate processes downstream of GPCRs generated great excitement in the field. This finding enhanced the understanding of these critical signaling pathways and provided potentially new targets for pharmacological intervention. These regulators of G-protein signaling (RGS) proteins were viewed by many as nodes downstream of GPCRs that could be targeted with small molecules to tune signaling processes. In this review, we provide a brief overview of the discovery of RGS proteins and of the gradual and continuing discovery of their roles in disease states, focusing particularly on cancer and neurological disorders. We also discuss high-throughput screening efforts that have led to the discovery first of peptide-based and then of small-molecule inhibitors targeting a subset of the RGS proteins. We explore the unique mechanisms of RGS inhibition these chemical tools have revealed and highlight the most up-to-date studies using these tools in animal experiments. Finally, we discuss the future opportunities in the field, as there are clearly more avenues left to be explored and potentials to be realized.
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Affiliation(s)
- Joseph B O'Brien
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242
| | - Joshua C Wilkinson
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242
| | - David L Roman
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242; Iowa Neuroscience Institute, Iowa City, Iowa 52242; Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242.
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8
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Gawel K, Banono NS, Michalak A, Esguerra CV. A critical review of zebrafish schizophrenia models: Time for validation? Neurosci Biobehav Rev 2019; 107:6-22. [PMID: 31381931 DOI: 10.1016/j.neubiorev.2019.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 07/02/2019] [Accepted: 08/01/2019] [Indexed: 12/14/2022]
Abstract
Schizophrenia is a mental disorder that affects 1% of the population worldwide and is manifested as a broad spectrum of symptoms, from hallucinations to memory impairment. It is believed that genetic and/or environmental factors may contribute to the occurrence of this disease. Recently, the zebrafish has emerged as a valuable and attractive model for various neurological disorders including schizophrenia. In this review, we describe current pharmacological models of schizophrenia with special emphasis on providing insights into the pros and cons of using zebrafish as a behavioural model of this disease. Moreover, we highlight the advantages and utility of using zebrafish for elucidating the genetic mechanisms underlying this psychiatric disorder. We believe that the zebrafish has high potential also in the area of precision medicine and may complement the development of therapeutics, especially for pharmacoresistant patients.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalléen 21, 0349, Oslo, Norway; Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland.
| | - Nancy Saana Banono
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalléen 21, 0349, Oslo, Norway
| | - Agnieszka Michalak
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki St. 4A, 20-093, Lublin, Poland
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalléen 21, 0349, Oslo, Norway; Department of Pharmacy, University of Oslo, Oslo, Norway.
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Huang MW, Lin YJ, Chang CW, Lei FJ, Ho EP, Liu RS, Shyu WC, Hsieh CH. RGS4 deficit in prefrontal cortex contributes to the behaviors related to schizophrenia via system x c--mediated glutamatergic dysfunction in mice. Am J Cancer Res 2018; 8:4781-4794. [PMID: 30279737 PMCID: PMC6160762 DOI: 10.7150/thno.25189] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 04/09/2018] [Indexed: 01/08/2023] Open
Abstract
Rationale: Although molecular investigations of regulator of G-protein signaling 4 (RGS4) alterations in schizophrenia patients yielded partially inconsistent findings, the previous studies suggested that RGS4 is both a positional and functional candidate gene for schizophrenia and is significantly decreased in the prefrontal cortex. However, the exact role of RGS4 in the pathophysiology of schizophrenia is unclear. Moreover, a whole genome transcription profile study showed the possibility of RGS4-regulated expression of SLC7A11(xCT), a component of cysteine/glutamate transporter or system xc-. We hypothesized that system xc- is a therapeutic target of RGS4 deficit-mediated schizophrenia. Methods: Pharmacological and genetic manipulation of RGS4 in organotypic brain slice cultures were used as an ex vivo model to investigate its role in system xc- and glutamatergic function. Lentiviral-based mouse models with RGS4 deficit in the prefrontal cortex and treatment with system xc- activator, N-acetyl cysteine (NAC), were utilized to observe their impacts on glutamatergic function and schizophrenic behaviors. Results: Genetic and pharmacological inhibition of RGS4 resulted in a significant decrease in SLC7A11 (xCT) expression and hypofunction of system xc- and reduced glutamatergic function in organotypic brain slice cultures. However, NAC restored the dysregulation of RGS4-mediated functional deficits of glutamate. Moreover, knockdown of RGS4 specifically in the prefrontal cortex caused mice to exhibit behaviors related to schizophrenia such as increased stereotypy, impaired prepulse inhibition, deficits in social interactions, working memory, and nesting behavior, while enhancing sensitivity to the locomotor stimulatory effect of MK-801. These mice displayed glutamatergic dysfunction in the prefrontal cortex, which may have contributed to the behavioral deficits. RGS4 knockdown mice that received NAC treatment had improved glutamatergic dysfunction and schizophrenia behaviors. Conclusion: Our results suggest that RGS4 deficit induces dysregulation and dysfunction of system xc-, which further results in functional deficits of the glutamatergic system and subsequently to schizophrenia-related behavioral phenotypes. Activation of system xc- offers a promising strategy to treat RGS4 deficit-mediated schizophrenia.
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10
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Petyuk VA, Chang R, Ramirez-Restrepo M, Beckmann ND, Henrion MYR, Piehowski PD, Zhu K, Wang S, Clarke J, Huentelman MJ, Xie F, Andreev V, Engel A, Guettoche T, Navarro L, De Jager P, Schneider JA, Morris CM, McKeith IG, Perry RH, Lovestone S, Woltjer RL, Beach TG, Sue LI, Serrano GE, Lieberman AP, Albin RL, Ferrer I, Mash DC, Hulette CM, Ervin JF, Reiman EM, Hardy JA, Bennett DA, Schadt E, Smith RD, Myers AJ. The human brainome: network analysis identifies HSPA2 as a novel Alzheimer’s disease target. Brain 2018; 141:2721-2739. [PMID: 30137212 PMCID: PMC6136080 DOI: 10.1093/brain/awy215] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/20/2018] [Accepted: 06/22/2018] [Indexed: 11/24/2022] Open
Abstract
Our hypothesis is that changes in gene and protein expression are crucial to the development of late-onset Alzheimer’s disease. Previously we examined how DNA alleles control downstream expression of RNA transcripts and how those relationships are changed in late-onset Alzheimer’s disease. We have now examined how proteins are incorporated into networks in two separate series and evaluated our outputs in two different cell lines. Our pipeline included the following steps: (i) predicting expression quantitative trait loci; (ii) determining differential expression; (iii) analysing networks of transcript and peptide relationships; and (iv) validating effects in two separate cell lines. We performed all our analysis in two separate brain series to validate effects. Our two series included 345 samples in the first set (177 controls, 168 cases; age range 65–105; 58% female; KRONOSII cohort) and 409 samples in the replicate set (153 controls, 141 cases, 115 mild cognitive impairment; age range 66–107; 63% female; RUSH cohort). Our top target is heat shock protein family A member 2 (HSPA2), which was identified as a key driver in our two datasets. HSPA2 was validated in two cell lines, with overexpression driving further elevation of amyloid-β40 and amyloid-β42 levels in APP mutant cells, as well as significant elevation of microtubule associated protein tau and phosphorylated-tau in a modified neuroglioma line. This work further demonstrates that studying changes in gene and protein expression is crucial to understanding late onset disease and further nominates HSPA2 as a specific key regulator of late-onset Alzheimer’s disease processes.10.1093/brain/awy215_video1awy215media15824729224001.
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Affiliation(s)
- Vladislav A Petyuk
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Rui Chang
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Manuel Ramirez-Restrepo
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Noam D Beckmann
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Marc Y R Henrion
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Paul D Piehowski
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Kuixi Zhu
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sven Wang
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jennifer Clarke
- Food Science and Technology Department, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Matthew J Huentelman
- Neurogenomics Division, The Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Fang Xie
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Victor Andreev
- Arbor Research Collaborative for Health, 340 E Huron St # 300, Ann Arbor, MI, USA
| | - Anzhelika Engel
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - Loida Navarro
- Roche Sequencing, 4300 Hacienda Drive, Pleasanton, CA, USA
| | - Philip De Jager
- Center for Translational and Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, New York, NY, USA
- New York Genome Center, New York NY, USA
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - Julie A Schneider
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Christopher M Morris
- Newcastle Brain Tissue Resource, Institute of Neuroscience, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK
| | - Ian G McKeith
- NIHR Biomedical Research Centre, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, UK
| | - Robert H Perry
- Neuropathology and Cellular Pathology, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, UK
| | - Simon Lovestone
- University of Oxford, Medical Sciences Division, Department of Psychiatry, Warneford Hospital, Oxford, UK
| | - Randall L Woltjer
- Neuropathology Core of the Layton Aging and Alzheimer’s Disease Center, Oregon Health and Science University, Portland, OR, USA
| | | | - Lucia I Sue
- Banner Sun Health Research Institute, Sun City, AZ, USA
| | | | | | - Roger L Albin
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Geriatrics Research, Education, and Clinical Center, VAAAHS, Ann Arbor, MI, USA
| | - Isidre Ferrer
- Department of Pathology and Experimental Therapeutics, University of Barcelona; CIBERNED; Hospitalet de Llobregat, Spain
| | - Deborah C Mash
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Christine M Hulette
- Department of Pathology, Division of Neuropathology, Duke University Medical Center, Durham, NC, USA
| | - John F Ervin
- Kathleen Price Bryan Brain Bank, Department of Medicine, Division of Neurology, Duke University, Durham, NC, USA
| | - Eric M Reiman
- The Arizona Alzheimer’s Consortium, Phoenix, Arizona, USA
- Banner Alzheimer’s Institute, Phoenix, Arizona, USA
| | - John A Hardy
- Department of Molecular Neuroscience and Reta Lila Research Laboratories, University College London Institute of Neurology, London, UK
| | - David A Bennett
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Eric Schadt
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Richard D Smith
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Amanda J Myers
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, USA
- Interdepartmental Program in Neuroscience, University of Miami Miller School of Medicine, Miami, FL, USA
- Interdepartmental Program in Human Genetics and Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
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11
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Rorabaugh BR, Rose MJ, Stoops TS, Stevens AA, Seeley SL, D'Souza MS. Regulators of G-protein signaling 2 and 4 differentially regulate cocaine-induced rewarding effects. Physiol Behav 2018; 195:9-19. [PMID: 30036561 DOI: 10.1016/j.physbeh.2018.07.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/16/2018] [Accepted: 07/19/2018] [Indexed: 01/11/2023]
Abstract
There is a need to identify new therapeutic targets for the treatment of cocaine addiction due to the rise in cocaine abuse and deaths due to cocaine overdose. Regulator of G protein signaling (RGS) proteins such as RGS2 and RGS4 are widely distributed in brain regions that play a role in drug reward. Importantly, RGS2 and RGS4 negatively regulate G-protein coupled receptor signaling pathways of monoaminergic neurotransmitters that play a role in the rewarding effects of cocaine by enhancing the rate of hydrolysis of Gα-bound guanine nucleotide triphosphate. Thus, the objective of this study was to investigate the effects of cocaine on conditioned place preference (CPP) and locomotor activity in mice that lacked either RGS2 or RGS4 (i.e. knockout (KO) mice) and their wildtype (WT) littermates. Moreover recent studies have reported influence of sex on RGS functioning and hence studies were conducted in both male and female mice. Cocaine-induced CPP was attenuated in male, but not female RGS4 KO mice compared to respective RGS4 WT mice. Cocaine-induced CPP was not influenced by deletion of RGS2 in either male or female mice. Similarly, cocaine-induced locomotor activity was not influenced by deletion of either RGS2 or RGS4 irrespective of sex. Together, the data indicate that the rewarding effects of cocaine were attenuated in the absence of RGS4 expression, but not in the absence of RGS2 expression in a sex-dependent manner. Importantly, these data suggest that RGS4 can serve as a potential target for medications that can be used to treat cocaine addiction.
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Affiliation(s)
- Boyd R Rorabaugh
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States
| | - Madison J Rose
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States
| | - Thorne S Stoops
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States
| | - Allison A Stevens
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States
| | - Sarah L Seeley
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States
| | - Manoranjan S D'Souza
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, 525 S Main Street, Ada, OH 45810, United States.
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12
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Kim J, Lee S, Kang S, Jeon TI, Kang MJ, Lee TH, Kim YS, Kim KS, Im HI, Moon C. Regulator of G-Protein Signaling 4 (RGS4) Controls Morphine Reward by Glutamate Receptor Activation in the Nucleus Accumbens of Mouse Brain. Mol Cells 2018; 41:454-464. [PMID: 29754475 PMCID: PMC5974622 DOI: 10.14348/molcells.2018.0023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/02/2018] [Accepted: 03/08/2018] [Indexed: 11/27/2022] Open
Abstract
Crosstalk between G-protein signaling and glutamatergic transmission within the brain reward circuits is critical for long-term emotional effects (depression and anxiety), cravings, and negative withdrawal symptoms associated with opioid addiction. A previous study showed that Regulator of G-protein signaling 4 (RGS4) may be implicated in opiate action in the nucleus accumbens (NAc). However, the mechanism of the NAc-specific RGS4 actions that induce the behavioral responses to opiates remains largely unknown. The present study used a short hairpin RNA (shRNA)-mediated knock-down of RGS4 in the NAc of the mouse brain to investigate the relationship between the activation of ionotropic glutamate receptors and RGS4 in the NAc during morphine reward. Additionally, the shRNA-mediated RGS4 knock-down was implemented in NAc/striatal primary-cultured neurons to investigate the role that striatal neurons have in the morphine-induced activation of ionotropic glutamate receptors. The results of this study show that the NAc-specific knockdown of RGS4 significantly increased the behaviors associated with morphine and did so by phosphorylation of the GluR1 (Ser831) and NR2A (Tyr1325) glutamate receptors in the NAc. Furthermore, the knock-down of RGS4 enhanced the phosphorylation of the GluR1 and NR2A glutamate receptors in the primary NAc/striatal neurons during spontaneous morphine withdrawal. These findings show a novel molecular mechanism of RGS4 in glutamatergic transmission that underlies the negative symptoms associated with morphine administration.
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Affiliation(s)
- Juhwan Kim
- Department of Veterinary Anatomy, College of Veterinary Medicine and BK21 Plus Project Team, Chonnam National University, Gwangju 61186,
Korea
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology (KIST), Seoul 02792,
Korea
- Department of Molecular Medicine (BK21plus), Chonnam National University Graduate School, Gwangju 61186,
Korea
| | - Sueun Lee
- Department of Veterinary Anatomy, College of Veterinary Medicine and BK21 Plus Project Team, Chonnam National University, Gwangju 61186,
Korea
| | - Sohi Kang
- Department of Veterinary Anatomy, College of Veterinary Medicine and BK21 Plus Project Team, Chonnam National University, Gwangju 61186,
Korea
| | - Tae-Il Jeon
- Department of Animal Science, College of Agriculture and Life Science, Chonnam National University, Gwangju 61186,
Korea
| | - Man-Jong Kang
- Department of Animal Science, College of Agriculture and Life Science, Chonnam National University, Gwangju 61186,
Korea
| | - Tae-Hoon Lee
- Department of Oral Biochemistry, Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju 61186,
Korea
- Department of Molecular Medicine (BK21plus), Chonnam National University Graduate School, Gwangju 61186,
Korea
| | - Yong Sik Kim
- Department of Pharmacology, Seoul National University College of Medicine, Seoul 08826,
Korea
| | - Key-Sun Kim
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology (KIST), Seoul 02792,
Korea
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792,
Korea
| | - Heh-In Im
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology (KIST), Seoul 02792,
Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792,
Korea
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792,
Korea
| | - Changjong Moon
- Department of Veterinary Anatomy, College of Veterinary Medicine and BK21 Plus Project Team, Chonnam National University, Gwangju 61186,
Korea
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13
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Schwarz E. A gene-based review of RGS4 as a putative risk gene for psychiatric illness. Am J Med Genet B Neuropsychiatr Genet 2018; 177:267-273. [PMID: 28544755 DOI: 10.1002/ajmg.b.32547] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/10/2017] [Indexed: 12/15/2022]
Abstract
Considerable efforts have been made to characterize RGS4 as a potential candidate gene for schizophrenia. Investigations span across numerous modalities and include explorations of genetic risk associations, mRNA and protein levels in the brain, and functionally relevant interactions with other candidate genes as well as links to schizophrenia relevant neural phenotypes. While these lines of investigations have yielded partially inconsistent findings, they provide a perspective on RGS4 as an important part of a larger biological system contributing to schizophrenia risk. This gene-based review aims to provide a comprehensive overview of published data from different experimental modalities and discusses the current knowledge of RGS4's systems-biological impact on the schizophrenia pathology.
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Affiliation(s)
- Emanuel Schwarz
- Medical Faculty Mannheim, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Heidelberg University, Mannheim, Germany
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14
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Madrigal A, Tan L, Zhao Y. Expression regulation and functional analysis of RGS2 and RGS4 in adipogenic and osteogenic differentiation of human mesenchymal stem cells. Biol Res 2017; 50:43. [PMID: 29279050 PMCID: PMC5742872 DOI: 10.1186/s40659-017-0148-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 12/14/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Understanding the molecular basis underlying the formation of bone-forming osteocytes and lipid-storing adipocytes will help provide insights into the cause of disorders originating in stem/progenitor cells and develop therapeutic treatments for bone- or adipose-related diseases. In this study, the role of RGS2 and RGS4, two members of the regulators of G protein signaling (RGS) family, was investigated during adipogenenic and osteogenenic differentiation of human mesenchymal stem cells (hMSCs). RESULTS Expression of RGS2 and RGS4 were found to be inversely regulated during adipogenesis induced by dexamethasone (DEX) and 3-isobutyl-methylxanthine, regardless if insulin was present, with RGS2 up-regulated and RGS4 down-regulated in response to adipogenic induction. RGS2 expression was also up-regulated during osteogenesis at a level similar to that induced by treatment of DEX alone, a shared component of adipogenic and osteogenic differentiation inducing media, but significantly lower than the level induced by adipogenic inducing media. RGS4 expression was down-regulated during the first 48 h of osteogenesis but up-regulated afterwards, in both cases at levels similar to that induced by DEX alone. Expression knock-down using small interfering RNA against RGS2 resulted in decreased differentiation efficiency during both adipogenesis and osteogenesis. On the other hand, expression knock-down of RGS4 also resulted in decreased adipogenic differentiation but increased osteogenic differentiation. CONCLUSIONS RGS2 and RGS4 are differentially regulated during adipogenic and osteogenic differentiation of hMSCs. In addition, both RGS2 and RGS4 play positive roles during adipogenesis but opposing roles during osteogenesis, with RGS2 as a positive regulator and RGS4 as a negative regulator. These results imply that members of RGS proteins may play multifaceted roles during human adipogenesis and osteogenesis to balance or counterbalance each other's function during those processes.
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Affiliation(s)
- Alma Madrigal
- Biological Sciences Department, California State Polytechnic University at Pomona, 3801 W. Temple Ave., Pomona, CA, 91768, USA.,Center for Biomedicine and Genetics, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA, 91010, USA
| | - Lun Tan
- Biological Sciences Department, California State Polytechnic University at Pomona, 3801 W. Temple Ave., Pomona, CA, 91768, USA
| | - Yuanxiang Zhao
- Biological Sciences Department, California State Polytechnic University at Pomona, 3801 W. Temple Ave., Pomona, CA, 91768, USA.
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15
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Pallotta MM, Ronca R, Carotenuto R, Porreca I, Turano M, Ambrosino C, Capriglione T. Specific Effects of Chronic Dietary Exposure to Chlorpyrifos on Brain Gene Expression-A Mouse Study. Int J Mol Sci 2017; 18:ijms18112467. [PMID: 29156651 PMCID: PMC5713433 DOI: 10.3390/ijms18112467] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/04/2017] [Accepted: 11/07/2017] [Indexed: 01/14/2023] Open
Abstract
Chlorpyrifos (CPF) is an organophosphate insecticide used to control pests on a variety of food and feed crops. In mammals, maternal exposure to CPF has been reported to induce cerebral cortex thinning, alteration of long-term brain cognitive function, and Parkinson-like symptoms, but the mechanisms of these processes are not fully understood. In this study, we aimed to gain a deeper understanding of the alterations induced in the brains of mice chronically exposed to CPF by dietary intake. For our purpose, we analysed F1 offspring (sacrificed at 3 and 8 months) of Mus musculus, treated in utero and postnatally with 3 different doses of CPF (0.1-1-10 mg/kg/day). Using RT2 Profiler PCR Arrays, we evaluated the alterations in the expression of 84 genes associated with neurodegenerative diseases. In the brains of exposed mice, we evidenced a clear dose–response relationship for AChE inhibition and alterations of gene expression. Some of the genes that were steadily down-regulated, such as Pink1, Park 2, Sv2b, Gabbr2, Sept5 and Atxn2, were directly related to Parkinson’s onset. Our experimental results shed light on the possibility that long-term CPF exposure may exert membrane signalling alterations which make brain cells more susceptible to develop neurodegenerative diseases.
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Affiliation(s)
- Maria Michela Pallotta
- Dipartimento di Biologia, Università di Napoli Federico II, Via Cinthia 21, 80126 Napoli, Italy.
| | - Raffaele Ronca
- Dipartimento di Biologia, Università di Napoli Federico II, Via Cinthia 21, 80126 Napoli, Italy.
| | - Rosa Carotenuto
- Dipartimento di Biologia, Università di Napoli Federico II, Via Cinthia 21, 80126 Napoli, Italy.
| | | | - Mimmo Turano
- Dipartimento di Biologia, Università di Napoli Federico II, Via Cinthia 21, 80126 Napoli, Italy.
| | - Concetta Ambrosino
- IRGS, Biogem, Via Camporeale, Ariano Irpino, 83031 Avellino, Italy.
- Dipartimento di Scienze e Tecnologie, Università del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy.
| | - Teresa Capriglione
- Dipartimento di Biologia, Università di Napoli Federico II, Via Cinthia 21, 80126 Napoli, Italy.
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16
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Ashrafi A, Garcia P, Kollmus H, Schughart K, Del Sol A, Buttini M, Glaab E. Absence of regulator of G-protein signaling 4 does not protect against dopamine neuron dysfunction and injury in the mouse 6-hydroxydopamine lesion model of Parkinson's disease. Neurobiol Aging 2017; 58:30-33. [PMID: 28697377 DOI: 10.1016/j.neurobiolaging.2017.06.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 06/11/2017] [Accepted: 06/12/2017] [Indexed: 10/19/2022]
Abstract
Regulator of G-protein signaling 4 (RGS4), a member of the RGS family of proteins that inactivate G-proteins, has gained interest as a potential drug target for neurological disorders, such as epilepsy and Parkinson's disease (PD). In the case of PD, the main current options for alleviating motor symptoms are dopamine replacement therapies, which have limitations because of side effects and reduced effectiveness over the long term. Research on new nondopaminergic PD drug targets has indicated that inhibition of RGS4 could be an effective adjuvant treatment option. The effectiveness of RGS4 inhibition for an array of PD-linked functional and structural neuroprotection end points has not yet been demonstrated. Here, we use the 6-hydroxydopamine (6-OHDA) lesioning model of the nigrostriatal pathway in mice to address this question. We observe, using a battery of behavioral and pathological measures, that mice deficient for RGS4 are not protected from 6-OHDA-induced injury and show enhanced susceptibility in some measures of motor function. Our results suggest that inhibition of RGS4 as a nondopaminergic target for PD should be approached with caution.
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Affiliation(s)
- Amer Ashrafi
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Pierre Garcia
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Heike Kollmus
- Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Klaus Schughart
- Helmholtz Centre for Infection Research, Braunschweig, Germany; Department of Infection Genetics, University of Veterinary Medicine Hannover, Hannover, Germany; Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, USA
| | - Antonio Del Sol
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Manuel Buttini
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Enrico Glaab
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg.
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17
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Bosier B, Doyen PJ, Brolet A, Muccioli GG, Ahmed E, Desmet N, Hermans E, Deumens R. Inhibition of the regulator of G protein signalling RGS4 in the spinal cord decreases neuropathic hyperalgesia and restores cannabinoid CB1 receptor signalling. Br J Pharmacol 2015; 172:5333-46. [PMID: 26478461 PMCID: PMC5341217 DOI: 10.1111/bph.13324] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 07/24/2015] [Accepted: 09/04/2015] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE Regulators of G protein signalling (RGS) are major determinants of metabotropic receptor activity, reducing the lifespan of the GTP-bound state of G proteins. Because the reduced potency of analgesic agents in neuropathic pain may reflect alterations in RGS, we assessed the effects of CCG 63802, a specific RGS4 inhibitor, on pain hypersensitivity and signalling through cannabinoid receptors, in a model of neuropathic pain. EXPERIMENTAL APPROACH The partial sciatic nerve ligation (PSNL) model in male Sprague Dawley rats was used to measure paw withdrawal thresholds to mechanical (von Frey hairs) or thermal (Hargreaves method) stimuli, during and after intrathecal injection of CCG 63802. HEK293 cells expressing CB1 receptors and conditional expression of RGS4 were used to correlate cAMP production and ERK phosphorylation with receptor activation and RGS4 action. KEY RESULTS Treatment of PSNL rats with CCG 63802, twice daily for 7 days after nerve injury, attenuated thermal hyperalgesia during treatment. Spinal levels of anandamide were higher in PSNL animals, irrespective of the treatment. Although expression of CB1 receptors was unaffected, HU210-induced CB1 receptor signalling was inhibited in PSNL rats and restored after intrathecal CCG 63802. In transfected HEK cells expressing CB1 receptors and RGS4, inhibition of cAMP production, a downstream effect of CB1 receptor signalling, was blunted after RGS4 overexpression. RGS4 expression also attenuated the CB1 receptor-controlled activation of ERK1/2. CONCLUSIONS AND IMPLICATIONS Inhibition of spinal RGS4 restored endogenous analgesic signalling pathways and mitigated neuropathic pain. Signalling through CB1 receptors may be involved in this beneficial effect.
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Affiliation(s)
- Barbara Bosier
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| | - Pierre J. Doyen
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| | - Amandine Brolet
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| | - Giulio G. Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research InstituteUniversité catholique de LouvainBrusselsBelgium
| | - Eman Ahmed
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
- Department of Clinical PharmacologyFaculty of Medicine, Suez Canal UniversityIsmailiaEgypt
| | - Nathalie Desmet
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| | - Emmanuel Hermans
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| | - Ronald Deumens
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
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18
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Santhappan R, Crowder AT, Gouty S, Cox BM, Côté TE. Mu opioid receptor activation enhances regulator of G protein signaling 4 association with the mu opioid receptor/G protein complex in a GTP-dependent manner. J Neurochem 2015; 135:76-87. [PMID: 26119705 PMCID: PMC5034817 DOI: 10.1111/jnc.13222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 06/19/2015] [Accepted: 06/25/2015] [Indexed: 11/26/2022]
Abstract
The interaction of Regulator of G protein Signaling 4 (RGS4) with the rat mu opioid receptor (MOR)/G protein complex was investigated. Solubilized MOR from rat brain membranes was immunoprecipitated in the presence of RGS4 with antibodies against the N-terminus of MOR (anti-MOR10-70 ). Activation of MOR with [D-Ala(2) , N-Me-Phe(4) , Gly(5) -ol] enkephalin (DAMGO) during immunoprecipitation caused a 150% increase in Goα and a 50% increase in RGS4 in the pellet. When 10 μM GTP was included with DAMGO, there was an additional 72% increase in RGS4 co-immunoprecipitating with MOR (p = 0.003). Guanosine 5'-O-(3-thiotriphosphate) (GTPγS) increased the amount of co-precipitating RGS4 by 93% (compared to DAMGO alone, p = 0.008), and the inclusion of GTPγS caused the ratio of MOR to RGS4 to be 1 : 1 (31 fmoles : 28 fmoles, respectively). GTPγS also increased the association of endogenous RGS4 with MOR. In His6 RGS4/Ni(2+) -NTA agarose pull down experiments, 0.3 μM GTPγS tripled the binding of Goα to His6 RGS4, whereas the addition of 100 μM GDP blocked this effect. Importantly, activation of solubilized MOR with DAMGO in the presence of 100 μM GDP and 0.3 μM GTPγS increased Goα binding to His6 RGS4/Ni(2+) -NTA agarose (p = 0.001). Regulators of G protein Signaling (RGS) shorten the time that G proteins are active. Activation of the mu opioid receptor (MOR) causes GTP to bind to and to activate Go (αoβγ). RGS4 then binds to the activated αo-GTP/MOR complex and accelerates the intrinsic GTPase of αo. After αo dissociates from MOR, RGS4 remains bound to the C-terminal region of MOR.
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Affiliation(s)
- Rema Santhappan
- Department of Pharmacology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Alicia Tamara Crowder
- Department of Pharmacology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Neuroscience Program, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Shawn Gouty
- Department of Pharmacology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Brian M Cox
- Department of Pharmacology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Neuroscience Program, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Thomas E Côté
- Department of Pharmacology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Neuroscience Program, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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19
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Osei-Owusu P, Blumer KJ. Regulator of G Protein Signaling 2: A Versatile Regulator of Vascular Function. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 133:77-92. [PMID: 26123303 DOI: 10.1016/bs.pmbts.2015.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Regulators of G protein signaling (RGS) proteins of the B/R4 family are widely expressed in the cardiovascular system where their role in fine-tuning G protein signaling is critical to maintaining homeostasis. Among members of this family, RGS2 and RGS5 have been shown to play key roles in cardiac and smooth muscle function by tightly regulating signaling pathways that are activated through Gq/11 and Gi/o classes of heterotrimeric G proteins. This chapter reviews accumulating evidence supporting a key role for RGS2 in vascular function and the implication of changes in RGS2 function and/or expression in the pathogenesis of blood pressure disorders, particularly hypertension. With such understanding, RGS2 and the signaling pathways it controls may emerge as novel targets for developing next-generation antihypertensive drugs/agents.
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Affiliation(s)
- Patrick Osei-Owusu
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA.
| | - Kendall J Blumer
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
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20
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Woodard GE, Jardín I, Berna-Erro A, Salido GM, Rosado JA. Regulators of G-protein-signaling proteins: negative modulators of G-protein-coupled receptor signaling. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 317:97-183. [PMID: 26008785 DOI: 10.1016/bs.ircmb.2015.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Regulators of G-protein-signaling (RGS) proteins are a category of intracellular proteins that have an inhibitory effect on the intracellular signaling produced by G-protein-coupled receptors (GPCRs). RGS along with RGS-like proteins switch on through direct contact G-alpha subunits providing a variety of intracellular functions through intracellular signaling. RGS proteins have a common RGS domain that binds to G alpha. RGS proteins accelerate GTPase and thus enhance guanosine triphosphate hydrolysis through the alpha subunit of heterotrimeric G proteins. As a result, they inactivate the G protein and quickly turn off GPCR signaling thus terminating the resulting downstream signals. Activity and subcellular localization of RGS proteins can be changed through covalent molecular changes to the enzyme, differential gene splicing, and processing of the protein. Other roles of RGS proteins have shown them to not be solely committed to being inhibitors but behave more as modulators and integrators of signaling. RGS proteins modulate the duration and kinetics of slow calcium oscillations and rapid phototransduction and ion signaling events. In other cases, RGS proteins integrate G proteins with signaling pathways linked to such diverse cellular responses as cell growth and differentiation, cell motility, and intracellular trafficking. Human and animal studies have revealed that RGS proteins play a vital role in physiology and can be ideal targets for diseases such as those related to addiction where receptor signaling seems continuously switched on.
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Affiliation(s)
- Geoffrey E Woodard
- Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Isaac Jardín
- Department of Physiology, University of Extremadura, Caceres, Spain
| | - A Berna-Erro
- Department of Physiology, University of Extremadura, Caceres, Spain
| | - Gines M Salido
- Department of Physiology, University of Extremadura, Caceres, Spain
| | - Juan A Rosado
- Department of Physiology, University of Extremadura, Caceres, Spain
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21
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The power of automated behavioural homecage technologies in characterizing disease progression in laboratory mice: A review. Appl Anim Behav Sci 2015. [DOI: 10.1016/j.applanim.2014.11.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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22
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Ganss R. Keeping the Balance Right. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 133:93-121. [DOI: 10.1016/bs.pmbts.2015.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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23
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Delesque-Touchard N, Pendaries C, Volle-Challier C, Millet L, Salel V, Hervé C, Pflieger AM, Berthou-Soulie L, Prades C, Sorg T, Herbert JM, Savi P, Bono F. Regulator of G-protein signaling 18 controls both platelet generation and function. PLoS One 2014; 9:e113215. [PMID: 25405900 PMCID: PMC4236145 DOI: 10.1371/journal.pone.0113215] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 10/24/2014] [Indexed: 01/10/2023] Open
Abstract
RGS18 is a myeloerythroid lineage-specific regulator of G-protein signaling, highly expressed in megakaryocytes (MKs) and platelets. In the present study, we describe the first generation of a RGS18 knockout mouse model (RGS18-/-). Interesting phenotypic differences between RGS18-/- and wild-type (WT) mice were identified, and show that RGS18 plays a significant role in both platelet generation and function. RGS18 deficiency produced a gain of function phenotype in platelets. In resting platelets, the level of CD62P expression was increased in RGS18-/- mice. This increase correlated with a higher level of plasmatic serotonin concentration. RGS18-/- platelets displayed a higher sensitivity to activation in vitro. RGS18 deficiency markedly increased thrombus formation in vivo. In addition, RGS18-/- mice presented a mild thrombocytopenia, accompanied with a marked deficit in MK number in the bone marrow. Analysis of MK maturation in vitro and in vivo revealed a defective megakaryopoiesis in RGS18-/- mice, with a lower bone marrow content of only the most committed MK precursors. Finally, RGS18 deficiency was correlated to a defect of platelet recovery in vivo under acute conditions of thrombocytopenia. Thus, we highlight a role for RGS18 in platelet generation and function, and provide additional insights into the physiology of RGS18.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Tania Sorg
- Department of Scientific Operations PhenoPro, Mouse Clinical Institute (MCI), Strasbourg, France
| | | | - Pierre Savi
- Early to Candidate (E2C), Sanofi, Toulouse, France
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24
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RGS4 is involved in the generation of abnormal involuntary movements in the unilateral 6-OHDA-lesioned rat model of Parkinson's disease. Neurobiol Dis 2014; 70:138-48. [PMID: 24969021 DOI: 10.1016/j.nbd.2014.06.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 06/15/2014] [Accepted: 06/17/2014] [Indexed: 12/31/2022] Open
Abstract
Regulators of G-protein signalling (RGS) proteins are implicated in striatal G-protein coupled receptor (GPCR) sensitisation in the pathophysiology of l-DOPA-induced abnormal involuntary movements (AIMs), also known as dyskinesia (LID), in Parkinson's disease (PD). In this study, we investigated RGS protein subtype 4 in the expression of AIMs in the unilateral 6-hydroxydopamine (6-OHDA)-lesioned rat model of LID. The effects of RGS4 antisense brain infusion on the behavioural and molecular correlates of l-DOPA priming in 6-OHDA-lesioned rats were assessed. In situ hybridisation revealed that repeated l-DOPA/benserazide treatment caused an elevation of RGS4 mRNA levels in the striatum, predominantly in the lateral regions. The increased expression of RGS4 mRNA in the rostral striatum was found to positively correlate with the behavioural (AIM scores) and molecular (pre-proenkephalin B, PPE-B expression) markers of LID. We found that suppressing the elevation of RGS4 mRNA in the striatum by continuous infusion of RGS4 antisense oligonucleotides, via implanted osmotic mini-pumps, during l-DOPA priming, reduced the induction of AIMs. Moreover, ex vivo analyses of the rostral dorsolateral striatum showed that RGS4 antisense infusion attenuated l-DOPA-induced elevations of PPE-B mRNA and dopamine-stimulated [(35)S]GTPγS binding, a marker used for measuring dopamine receptor super-sensitivity. Taken together, these data suggest that (i) RGS4 proteins play an important pathophysiological role in the development and expression of LID and (ii) suppressing the elevation of RGS4 mRNA levels in l-DOPA priming attenuates the associated pathological changes in LID, dampening its physiological expression. Thus, modulating RGS4 proteins could prove beneficial in the treatment of dyskinesia in PD.
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25
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Kim HJ, Ryu J, Woo HM, Cho SS, Sung MK, Kim SC, Park MH, Park T, Koo SK. Patterns of gene expression associated with Pten deficiency in the developing inner ear. PLoS One 2014; 9:e97544. [PMID: 24893171 PMCID: PMC4043736 DOI: 10.1371/journal.pone.0097544] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 04/19/2014] [Indexed: 12/26/2022] Open
Abstract
In inner ear development, phosphatase and tensin homolog (PTEN) is necessary for neuronal maintenance, such as neuronal survival and accurate nerve innervations of hair cells. We previously reported that Pten conditional knockout (cKO) mice exhibited disorganized fasciculus with neuronal apoptosis in spiral ganglion neurons (SGNs). To better understand the genes and signaling networks related to auditory neuron maintenance, we compared the profiles of differentially expressed genes (DEGs) using microarray analysis of the inner ear in E14.5 Pten cKO and wild-type mice. We identified 46 statistically significant transcripts using significance analysis of microarrays, with the false-discovery rate set at 0%. Among the DEGs, expression levels of candidate genes and expression domains were validated by quantitative real-time RT-PCR and in situ hybridization, respectively. Ingenuity pathway analysis using DEGs identified significant signaling networks associated with apoptosis, cellular movement, and axon guidance (i.e., secreted phosphoprotein 1 (Spp1)-mediated cellular movement and regulator of G-protein signaling 4 (Rgs4)-mediated axon guidance). This result was consistent with the phenotypic defects of SGNs in Pten cKO mice (e.g., neuronal apoptosis, abnormal migration, and irregular nerve fiber patterns of SGNs). From this study, we suggest two key regulatory signaling networks mediated by Spp1 and Rgs4, which may play potential roles in neuronal differentiation of developing auditory neurons.
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Affiliation(s)
- Hyung Jin Kim
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, South Korea
| | - Jihee Ryu
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, South Korea
| | - Hae-Mi Woo
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, South Korea
| | - Samuel Sunghwan Cho
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, South Korea
| | - Min Kyung Sung
- Korean BioInformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Sang Cheol Kim
- Korean BioInformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Mi-Hyun Park
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, South Korea
| | - Taesung Park
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, South Korea
- Department of Statistics, Seoul National University, Seoul, South Korea
| | - Soo Kyung Koo
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, South Korea
- * E-mail:
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26
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Manganese-enhanced magnetic resonance imaging reveals increased DOI-induced brain activity in a mouse model of schizophrenia. Proc Natl Acad Sci U S A 2014; 111:E2492-500. [PMID: 24889602 DOI: 10.1073/pnas.1323287111] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Maternal infection during pregnancy increases the risk for schizophrenia in offspring. In rodent models, maternal immune activation (MIA) yields offspring with schizophrenia-like behaviors. None of these behaviors are, however, specific to schizophrenia. The presence of hallucinations is a key diagnostic symptom of schizophrenia. In mice, this symptom can be defined as brain activation in the absence of external stimuli, which can be mimicked by administration of hallucinogens. We find that, compared with controls, adult MIA offspring display an increased stereotypical behavioral response to the hallucinogen 2,5-dimethoxy-4-iodoamphetamine (DOI), an agonist for serotonin receptor 2A (5-HT2AR). This may be explained by increased levels of 5-HT2AR and downstream signaling molecules in unstimulated MIA prefrontal cortex (PFC). Using manganese-enhanced magnetic resonance imaging to identify neuronal activation elicited by DOI administration, we find that, compared with controls, MIA offspring exhibit a greater manganese (Mn(2+)) accumulation in several brain areas, including the PFC, thalamus, and striatum. The parafascicular thalamic nucleus, which plays the role in the pathogenesis of hallucinations, is activated by DOI in MIA offspring only. Additionally, compared with controls, MIA offspring demonstrate higher DOI-induced expression of early growth response protein 1, cyclooxygenase-2, and brain-derived neurotrophic factor in the PFC. Chronic treatment with the 5-HT2AR antagonist ketanserin reduces DOI-induced head twitching in MIA offspring. Thus, the MIA mouse model can be successfully used to investigate activity induced by DOI in awake, behaving mice. Moreover, manganese-enhanced magnetic resonance imaging is a useful, noninvasive method for accurately measuring this type of activity.
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27
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Ha S, Stottmann RW, Furley AJ, Beier DR. A forward genetic screen in mice identifies mutants with abnormal cortical patterning. ACTA ACUST UNITED AC 2013; 25:167-79. [PMID: 23968836 DOI: 10.1093/cercor/bht209] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Formation of a 6-layered cortical plate and axon tract patterning are key features of cerebral cortex development. Abnormalities of these processes may be the underlying cause for a range of functional disabilities seen in human neurodevelopmental disorders. To identify mouse mutants with defects in cortical lamination or corticofugal axon guidance, N-ethyl-N-nitrosourea (ENU) mutagenesis was performed using mice expressing LacZ reporter genes in layers II/III and V of the cortex (Rgs4-lacZ) or in corticofugal axons (TAG1-tau-lacZ). Four lines with abnormal cortical lamination have been identified. One of these was a splice site mutation in reelin (Reln) that results in a premature stop codon and the truncation of the C-terminal region (CTR) domain of reelin. Interestingly, this novel allele of Reln did not display cerebellar malformation or ataxia, and this is the first report of a Reln mutant without a cerebellar defect. Four lines with abnormal cortical axon development were also identified, one of which was found by whole-genome resequencing to carry a mutation in Lrp2. These findings demonstrated that the application of ENU mutagenesis to mice carrying transgenic reporters marking cortical anatomy is a sensitive and specific method to identify mutations that disrupt patterning of the developing brain.
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Affiliation(s)
- Seungshin Ha
- Genetics Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA 98101, USA
| | - Rolf W Stottmann
- Genetics Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA Divisions of Human Genetics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA and
| | - Andrew J Furley
- Department of Biomedical Science, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - David R Beier
- Genetics Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA 98101, USA
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28
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Differential control of opioid antinociception to thermal stimuli in a knock-in mouse expressing regulator of G-protein signaling-insensitive Gαo protein. J Neurosci 2013; 33:4369-77. [PMID: 23467353 DOI: 10.1523/jneurosci.5470-12.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Regulator of G-protein signaling (RGS) proteins classically function as negative modulators of G-protein-coupled receptor signaling. In vitro, RGS proteins have been shown to inhibit signaling by agonists at the μ-opioid receptor, including morphine. The goal of the present study was to evaluate the contribution of endogenous RGS proteins to the antinociceptive effects of morphine and other opioid agonists. To do this, a knock-in mouse that expresses an RGS-insensitive (RGSi) mutant Gαo protein, Gαo(G184S) (Gαo RGSi), was evaluated for morphine or methadone antinociception in response to noxious thermal stimuli. Mice expressing Gαo RGSi subunits exhibited a naltrexone-sensitive enhancement of baseline latency in both the hot-plate and warm-water tail-withdrawal tests. In the hot-plate test, a measure of supraspinal nociception, morphine antinociception was increased, and this was associated with an increased ability of opioids to inhibit presynaptic GABA neurotransmission in the periaqueductal gray. In contrast, antinociception produced by either morphine or methadone was reduced in the tail-withdrawal test, a measure of spinal nociception. In whole-brain and spinal cord homogenates from mice expressing Gαo RGSi subunits, there was a small loss of Gαo expression and an accompanying decrease in basal G-protein activity. Our results strongly support a role for RGS proteins as negative regulators of opioid supraspinal antinociception and also reveal a potential novel function of RGS proteins as positive regulators of opioid spinal antinociceptive pathways.
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29
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Cheng YC, Scotting PJ, Hsu LS, Lin SJ, Shih HY, Hsieh FY, Wu HL, Tsao CL, Shen CJ. Zebrafish rgs4 is essential for motility and axonogenesis mediated by Akt signaling. Cell Mol Life Sci 2013; 70:935-50. [PMID: 23052218 PMCID: PMC11113239 DOI: 10.1007/s00018-012-1178-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Revised: 09/19/2012] [Accepted: 09/24/2012] [Indexed: 12/21/2022]
Abstract
The schizophrenia susceptibility gene, Rgs4, is one of the most intensively studied regulators of G-protein signaling members, well known to be fundamental in regulating neurotransmission. However, little is known about its role in the developing nervous system. We have isolated zebrafish rgs4 and shown that it is transcribed in the developing nervous system. Rgs4 knockdown did not affect neuron number and patterning but resulted in locomotion defects and aberrant development of axons. This was confirmed using a selective Rgs4 inhibitor, CCG-4986. Rgs4 knockdown also attenuated the level of phosphorylated-Akt1, and injection of constitutively-activated AKT1 rescued the motility defects and axonal phenotypes in the spinal cord but not in the hindbrain and trigeminal neurons. Our in vivo analysis reveals a novel role for Rgs4 in regulating axonogenesis during embryogenesis, which is mediated by another schizophrenia-associated gene, Akt1, in a region-specific manner.
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Affiliation(s)
- Yi-Chuan Cheng
- Graduate Institute of Biomedical Sciences, School of Medicine, Chang Gung University, Taoyuan, 33383, Taiwan.
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30
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Wang Q, Traynor JR. Modulation of μ-opioid receptor signaling by RGS19 in SH-SY5Y cells. Mol Pharmacol 2013; 83:512-20. [PMID: 23197645 PMCID: PMC3558815 DOI: 10.1124/mol.112.081992] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 11/29/2012] [Indexed: 02/03/2023] Open
Abstract
Regulator of G-protein signaling protein 19 (RGS19), also known as Gα-interacting protein (GAIP), acts as a GTPase accelerating protein for Gαz as well as Gαi/o subunits. Interactions with GAIP-interacting protein N-terminus and GAIP-interacting protein C-terminus (GIPC) link RGS19 to a variety of intracellular proteins. Here we show that RGS19 is abundantly expressed in human neuroblastoma SH-SY5Y cells that also express µ- and δ- opioid receptors (MORs and DORs, respectively) and nociceptin receptors (NOPRs). Lentiviral delivery of short hairpin RNA specifically targeted to RGS19 reduced RGS19 protein levels by 69%, with a similar reduction in GIPC. In RGS19-depleted cells, there was an increase in the ability of MOR (morphine) but not of DOR [(4-[(R)-[(2S,5R)-4-allyl-2,5-dimethylpiperazin-1-yl](3-methoxyphenyl)methyl]-N,N-diethylbenzamide (SNC80)] or NOPR (nociceptin) agonists to inhibit forskolin-stimulated adenylyl cyclase and increase mitogen-activated protein kinase (MAPK) activity. Overnight treatment with either MOR [D-Ala, N-Me-Phe, Gly-ol(5)-enkephalin (DAMGO) or morphine] or DOR (D-Pen(5)-enkephalin or SNC80) agonists increased RGS19 and GIPC protein levels in a time- and concentration-dependent manner. The MOR-induced increase in RGS19 protein was prevented by pretreatment with pertussis toxin or the opioid antagonist naloxone. Protein kinase C (PKC) activation alone increased the level of RGS19 and inhibitors of PKC 5,6,7,13-tetrahydro-13-methyl-5-oxo-12H-indolo[2,3-a]pyrrolo[3,4-c]carbazole-12-propanenitrile and mitogen-activated protein kinase kinase 1 2-(2-amino-3-methoxyphenyl)-4H-chromen-4-one, but not protein kinase A (H89), completely blocked DAMGO-induced RGS19 protein accumulation. The findings show that RGS19 and GIPC are jointly regulated, that RGS19 is a GTPase accelerating protein for MOR with selectivity over DOR and NOPR, and that chronic MOR or DOR agonist treatment increases RGS19 levels by a PKC and the MAPK pathway-dependent mechanism.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Adenylyl Cyclases/genetics
- Adenylyl Cyclases/metabolism
- Animals
- Benzamides/pharmacology
- Colforsin/pharmacology
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- HEK293 Cells
- Humans
- Mitogen-Activated Protein Kinases/genetics
- Mitogen-Activated Protein Kinases/metabolism
- Morphine/pharmacology
- Opioid Peptides/pharmacology
- PC12 Cells
- Piperazines/pharmacology
- Protein Kinase C/genetics
- Protein Kinase C/metabolism
- RGS Proteins/genetics
- RGS Proteins/metabolism
- Rats
- Receptors, Opioid/genetics
- Receptors, Opioid/metabolism
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Signal Transduction/drug effects
- Nociceptin Receptor
- Nociceptin
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Affiliation(s)
- Qin Wang
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109-5632, USA
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31
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Ullah N, Ul Islam N, Ali G, Subhan F, Faridoon, Khan I. Bioisosteric synthesis of nitrogen containing derivatives of salicyl alcohol, their in vivo pharmacological studies with molecular modeling. Med Chem Res 2013. [DOI: 10.1007/s00044-013-0473-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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32
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Aguilar B, Choi I, Choi D, Chung HK, Lee S, Yoo J, Lee YS, Maeng YS, Lee HN, Park E, Kim KE, Kim NY, Baik JM, Jung JU, Koh CJ, Hong YK. Lymphatic reprogramming by Kaposi sarcoma herpes virus promotes the oncogenic activity of the virus-encoded G-protein-coupled receptor. Cancer Res 2012; 72:5833-42. [PMID: 22942256 PMCID: PMC3500425 DOI: 10.1158/0008-5472.can-12-1229] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Kaposi sarcoma, the most common cancer in HIV-positive individuals, is caused by endothelial transformation mediated by the Kaposi sarcoma herpes virus (KSHV)-encoded G-protein-coupled receptor (vGPCR). Infection of blood vascular endothelial cells (BEC) by KSHV reactivates an otherwise silenced embryonic program of lymphatic differentiation. Thus, Kaposi sarcoma tumors express numerous lymphatic endothelial cell (LEC) signature genes. A key unanswered question is how lymphatic reprogramming by the virus promotes tumorigenesis leading to Kaposi sarcoma formation. In this study, we present evidence that this process creates an environment needed to license the oncogenic activity of vGPCR. We found that the G-protein regulator RGS4 is an inhibitor of vGPCR that is expressed in BECs, but not in LECs. RGS4 was downregulated by the master regulator of LEC differentiation PROX1, which is upregulated by KSHV and directs KSHV-induced lymphatic reprogramming. Moreover, we found that KSHV upregulates the nuclear receptor LRH1, which physically interacts with PROX1 and synergizes with it to mediate repression of RGS4 expression. Mechanistic investigations revealed that RGS4 reduced vGPCR-enhanced cell proliferation, migration, VEGF expression, and Akt activation and suppressed tumor formation induced by vGPCR. Our findings resolve long-standing questions about the pathologic impact of KSHV-induced reprogramming of host cell identity, and they offer biologic and mechanistic insights supporting the hypothesis that a lymphatic microenvironment is more favorable for Kaposi sarcoma tumorigenesis.
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MESH Headings
- Animals
- Cell Differentiation/physiology
- Cell Transformation, Viral
- Down-Regulation
- Endothelial Cells/metabolism
- Endothelial Cells/pathology
- Endothelial Cells/virology
- Female
- Herpesvirus 8, Human/genetics
- Herpesvirus 8, Human/metabolism
- Herpesvirus 8, Human/physiology
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Mice, Nude
- Mice, SCID
- Oncogene Protein v-akt/metabolism
- Promoter Regions, Genetic
- RGS Proteins/antagonists & inhibitors
- RGS Proteins/biosynthesis
- RGS Proteins/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/physiology
- Tumor Suppressor Proteins/genetics
- Tumor Suppressor Proteins/metabolism
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Affiliation(s)
- Berenice Aguilar
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Inho Choi
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Dongwon Choi
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Hee Kyoung Chung
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Sunju Lee
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Jaehyuk Yoo
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Yong Suk Lee
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Yong Sun Maeng
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Ha Neul Lee
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Eunkyung Park
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Kyu Eui Kim
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Nam Yoon Kim
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Jae Myung Baik
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Jae U. Jung
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Chester J. Koh
- Division of Pediatric Urology and Developmental Biology, Regenerative Medicine, and Surgery Program, Children’s Hospital Los Angeles and University of Southern California Keck School of Medicine, Los Angeles, California 90027
| | - Young-Kwon Hong
- Department of Surgery and Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
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33
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Hoekstra EJ, von Oerthel L, van der Linden AJA, Schellevis RD, Scheppink G, Holstege FCP, Groot-Koerkamp MJ, van der Heide LP, Smidt MP. Lmx1a is an activator of Rgs4 and Grb10 and is responsible for the correct specification of rostral and medial mdDA neurons. Eur J Neurosci 2012; 37:23-32. [PMID: 23106268 DOI: 10.1111/ejn.12022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 09/12/2012] [Accepted: 09/13/2012] [Indexed: 11/26/2022]
Abstract
The LIM homeodomain transcription factor Lmx1a is a very potent inducer of stem cells towards dopaminergic neurons. Despite several studies on the function of this gene, the exact in vivo role of Lmx1a in mesodiencephalic dopamine (mdDA) neuronal specification is still not understood. To analyse the genes functioning downstream of Lmx1a, we performed expression microarray analysis of LMX1A-overexpressing MN9D dopaminergic cells. Several interesting regulated genes were identified, based on their regulation in other previously generated expression arrays and on their expression pattern in the developing mdDA neuronal field. Post analysis through in vivo expression analysis in Lmx1a mouse mutant (dr/dr) embryos demonstrated a clear decrease in expression of the genes Grb10 and Rgs4, in and adjacent to the rostral and dorsal mdDA neuronal field and within the Lmx1a expression domain. Interestingly, the DA marker Vmat2 was significantly up-regulated as a consequence of increased LMX1A dose, and subsequent analysis on Lmx1a-mutant E14.5 and adult tissue revealed a significant decrease in Vmat2 expression in mdDA neurons. Taken together, microarray analysis of an LMX1A-overexpression cell system resulted in the identification of novel direct or indirect downstream targets of Lmx1a in mdDA neurons: Grb10, Rgs4 and Vmat2.
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Affiliation(s)
- Elisa J Hoekstra
- Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
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34
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Ayalew M, Le-Niculescu H, Levey DF, Jain N, Changala B, Patel SD, Winiger E, Breier A, Shekhar A, Amdur R, Koller D, Nurnberger JI, Corvin A, Geyer M, Tsuang MT, Salomon D, Schork NJ, Fanous AH, O'Donovan MC, Niculescu AB. Convergent functional genomics of schizophrenia: from comprehensive understanding to genetic risk prediction. Mol Psychiatry 2012; 17:887-905. [PMID: 22584867 PMCID: PMC3427857 DOI: 10.1038/mp.2012.37] [Citation(s) in RCA: 322] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 02/28/2012] [Accepted: 03/05/2012] [Indexed: 02/07/2023]
Abstract
We have used a translational convergent functional genomics (CFG) approach to identify and prioritize genes involved in schizophrenia, by gene-level integration of genome-wide association study data with other genetic and gene expression studies in humans and animal models. Using this polyevidence scoring and pathway analyses, we identify top genes (DISC1, TCF4, MBP, MOBP, NCAM1, NRCAM, NDUFV2, RAB18, as well as ADCYAP1, BDNF, CNR1, COMT, DRD2, DTNBP1, GAD1, GRIA1, GRIN2B, HTR2A, NRG1, RELN, SNAP-25, TNIK), brain development, myelination, cell adhesion, glutamate receptor signaling, G-protein-coupled receptor signaling and cAMP-mediated signaling as key to pathophysiology and as targets for therapeutic intervention. Overall, the data are consistent with a model of disrupted connectivity in schizophrenia, resulting from the effects of neurodevelopmental environmental stress on a background of genetic vulnerability. In addition, we show how the top candidate genes identified by CFG can be used to generate a genetic risk prediction score (GRPS) to aid schizophrenia diagnostics, with predictive ability in independent cohorts. The GRPS also differentiates classic age of onset schizophrenia from early onset and late-onset disease. We also show, in three independent cohorts, two European American and one African American, increasing overlap, reproducibility and consistency of findings from single-nucleotide polymorphisms to genes, then genes prioritized by CFG, and ultimately at the level of biological pathways and mechanisms. Finally, we compared our top candidate genes for schizophrenia from this analysis with top candidate genes for bipolar disorder and anxiety disorders from previous CFG analyses conducted by us, as well as findings from the fields of autism and Alzheimer. Overall, our work maps the genomic and biological landscape for schizophrenia, providing leads towards a better understanding of illness, diagnostics and therapeutics. It also reveals the significant genetic overlap with other major psychiatric disorder domains, suggesting the need for improved nosology.
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Affiliation(s)
- M Ayalew
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
- Indianapolis VA Medical Center, Indianapolis, IN, USA
| | - H Le-Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - D F Levey
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - N Jain
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - B Changala
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - S D Patel
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - E Winiger
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Breier
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Shekhar
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - R Amdur
- Washington DC VA Medical Center, Washington, DC, USA
| | - D Koller
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - J I Nurnberger
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Corvin
- Department of Psychiatry, Trinity College, Dublin, Ireland
| | - M Geyer
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - M T Tsuang
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - D Salomon
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - N J Schork
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - A H Fanous
- Washington DC VA Medical Center, Washington, DC, USA
| | - M C O'Donovan
- Department of Psychological Medicine, School of Medicine, Cardiff University, Cardiff, UK
| | - A B Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
- Indianapolis VA Medical Center, Indianapolis, IN, USA
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Neurabin scaffolding of adenosine receptor and RGS4 regulates anti-seizure effect of endogenous adenosine. J Neurosci 2012; 32:2683-95. [PMID: 22357852 DOI: 10.1523/jneurosci.4125-11.2011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Endogenous adenosine is an essential protective agent against neural damage by various insults to the brain. However, the therapeutic potential of adenosine receptor-directed ligands for neuroprotection is offset by side effects in peripheral tissues and organs. An increase in adenosine receptor responsiveness to endogenous adenosine would enhance neuroprotection while avoiding the confounding effects of exogenous ligands. Here we report novel regulation of adenosine-evoked responses by a neural tissue-specific protein, neurabin. Neurabin attenuated adenosine A(1) receptor (A1R) signaling by assembling a complex between the A1R and the regulator of G-protein signaling 4 (RGS4), a protein known to turn off G-protein signaling. Inactivation of the neurabin gene enhanced A1R signaling and promoted the protective effect of adenosine against excitotoxic seizure and neuronal death in mice. Furthermore, administration of a small molecule inhibitor of RGS4 significantly attenuated seizure severity in mice. Notably, the dose of kainate capable of inducing an ∼50% rate of death in wild-type (WT) mice did not affect neurabin-null mice or WT mice cotreated with an RGS4 inhibitor. The enhanced anti-seizure and neuroprotective effect achieved by disruption of the A1R/neurabin/RGS4 complex is elicited by the on-site and on-demand release of endogenous adenosine, and does not require administration of A1R ligands. These data identify neurabin-RGS4 as a novel tissue-selective regulatory mechanism for fine-tuning adenosine receptor function in the nervous system. Moreover, these findings implicate the A1R/neurabin/RGS4 complex as a valid therapeutic target for specifically manipulating the neuroprotective effects of endogenous adenosine.
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Traynor J. μ-Opioid receptors and regulators of G protein signaling (RGS) proteins: from a symposium on new concepts in mu-opioid pharmacology. Drug Alcohol Depend 2012; 121:173-80. [PMID: 22129844 PMCID: PMC3288798 DOI: 10.1016/j.drugalcdep.2011.10.027] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 08/19/2011] [Accepted: 10/22/2011] [Indexed: 02/07/2023]
Abstract
Mu-opioid receptors (MOR) are the therapeutic target for opiate analgesic drugs and also mediate many of the side-effects and addiction liability of these compounds. MOR is a seven-transmembrane domain receptor that couples to intracellular signaling molecules by activating heterotrimeric G proteins. However, the receptor and G protein do not function in isolation but their activities are moderated by several accessory and scaffolding proteins. One important group of accessory proteins is the regulator of G protein signaling (RGS) protein family, a large family of more than thirty members which bind to the activated Gα subunit of the heterotrimeric G protein and serve to accelerate signal termination. This action negatively modulates receptor signaling and subsequent behavior. Several members of this family, in particular RGS4 and RGS9-2 have been demonstrated to influence MOR signaling and morphine-induced behaviors, including reward. Moreover, this interaction is not unidirectional since morphine has been demonstrated to modulate expression levels of RGS proteins, especially RGS4 and RGS9-2, in a tissue and time dependent manner. In this article, I will discuss our work on the regulation of MOR signaling by RGS protein activity in cultured cell systems in the context of other in vitro and behavioral studies. In addition I will consider implications of the bi-directional interaction between MOR receptor activation and RGS protein activity and whether RGS proteins might provide a suitable and novel target for medications to manage addictive behaviors.
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Affiliation(s)
- John Traynor
- Department of Pharmacology and Substance Abuse Research Center, University of Michigan, Ann Arbor, MI 48109-5632, United States.
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Roman DL, Traynor JR. Regulators of G protein signaling (RGS) proteins as drug targets: modulating G-protein-coupled receptor (GPCR) signal transduction. J Med Chem 2011; 54:7433-40. [PMID: 21916427 DOI: 10.1021/jm101572n] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David L Roman
- College of Pharmacy, The University of Iowa , Iowa City, IA 52242, USA
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Abstract
Signal transduction through G-protein-coupled receptors (GPCRs) is central for the regulation of virtually all cellular functions and has been widely implicated in human disease. Regulators of G-protein signaling (RGS proteins) belong to a diverse protein family that was originally discovered for their ability to accelerate signal termination in response to GPCR stimulation, thereby reducing the amplitude and duration of GPCR effects. All RGS proteins share a common RGS domain that interacts with G protein α subunits and mediates their biological regulation of GPCR signaling. However, RGS proteins differ widely in size and the organization of their sequences flanking the RGS domain, which contain several additional functional domains that facilitate protein-protein (or protein-lipid) interactions. RGS proteins are subject to posttranslational modifications, and, in addition, their expression, activity, and subcellular localization can be dynamically regulated. Thus, there exists a wide array of mechanisms that facilitate their proper function as modulators and integrators of G-protein signaling. Several RGS proteins have been implicated in the cardiac remodeling response and heart rate regulation, and changes in RGS protein expression and/or function are believed to participate in the pathophysiology of cardiac hypertrophy, failure and arrhythmias as well as hypertension. This review is based on recent advances in our understanding of the expression pattern, regulation, and functional role of canonical RGS proteins, with a special focus on the healthy heart and the diseased heart. In addition, we discuss their potential and promise as therapeutic targets as well as strategies to modulate their expression and function.
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Affiliation(s)
- Peng Zhang
- Cardiovascular Research Center, Rhode Island Hospital and Alpert Medical School of Brown University, 1 Hoppin St, Providence, RI 02903, USA
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Lin CY, Sawa A, Jaaro-Peled H. Better understanding of mechanisms of schizophrenia and bipolar disorder: from human gene expression profiles to mouse models. Neurobiol Dis 2011; 45:48-56. [PMID: 21914480 DOI: 10.1016/j.nbd.2011.08.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 08/22/2011] [Accepted: 08/26/2011] [Indexed: 01/01/2023] Open
Abstract
The molecular mechanisms of major mental illnesses, such as schizophrenia and bipolar disorder, are unclear. To address this fundamental question, many groups have studied molecular expression profiles in postmortem brains and other tissues from patients compared with those from normal controls. Development of unbiased high-throughput approaches, such as microarray, RNA-seq, and proteomics, have supported and facilitated this endeavor. In addition to genes directly involved in neuron/glia signaling, especially those encoding for synaptic proteins, genes for metabolic cascades are differentially expressed in the brains of patients with schizophrenia and bipolar disorder, compared with those from normal controls in DNA microarray studies. Here we propose the importance and usefulness of genetic mouse models in which such differentially expressed molecules are modulated. These animal models allow us to dissect the mechanisms of how such molecular changes in patient brains may play a role in neuronal circuitries and overall behavioral phenotypes. We also point out that models in which the metabolic genes are modified are obviously untested from mental illness viewpoints, suggesting the potential to re-address these models with behavioral assays and neurochemical assessments.
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Affiliation(s)
- Chi-Ying Lin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Kimple AJ, Bosch DE, Giguère PM, Siderovski DP. Regulators of G-protein signaling and their Gα substrates: promises and challenges in their use as drug discovery targets. Pharmacol Rev 2011; 63:728-49. [PMID: 21737532 DOI: 10.1124/pr.110.003038] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Because G-protein coupled receptors (GPCRs) continue to represent excellent targets for the discovery and development of small-molecule therapeutics, it is posited that additional protein components of the signal transduction pathways emanating from activated GPCRs themselves are attractive as drug discovery targets. This review considers the drug discovery potential of two such components: members of the "regulators of G-protein signaling" (RGS protein) superfamily, as well as their substrates, the heterotrimeric G-protein α subunits. Highlighted are recent advances, stemming from mouse knockout studies and the use of "RGS-insensitivity" and fast-hydrolysis mutations to Gα, in our understanding of how RGS proteins selectively act in (patho)physiologic conditions controlled by GPCR signaling and how they act on the nucleotide cycling of heterotrimeric G-proteins in shaping the kinetics and sensitivity of GPCR signaling. Progress is documented regarding recent activities along the path to devising screening assays and chemical probes for the RGS protein target, not only in pursuits of inhibitors of RGS domain-mediated acceleration of Gα GTP hydrolysis but also to embrace the potential of finding allosteric activators of this RGS protein action. The review concludes in considering the Gα subunit itself as a drug target, as brought to focus by recent reports of activating mutations to GNAQ and GNA11 in ocular (uveal) melanoma. We consider the likelihood of several strategies for antagonizing the function of these oncogene alleles and their gene products, including the use of RGS proteins with Gα(q) selectivity.
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Affiliation(s)
- Adam J Kimple
- Department of Pharmacology, UNC Neuroscience Center, UNC School of Medicine, University of North Carolina at Chapel Hill, 120 Mason Farm Road, Suite 4010, Chapel Hill, NC 27599-7365, USA
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Lazar NL, Neufeld RWJ, Cain DP. Contribution of nonprimate animal models in understanding the etiology of schizophrenia. J Psychiatry Neurosci 2011; 36:E5-29. [PMID: 21247514 PMCID: PMC3120891 DOI: 10.1503/jpn.100054] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Schizophrenia is a severe psychiatric disorder that is characterized by positive and negative symptoms and cognitive impairments. The etiology of the disorder is complex, and it is thought to follow a multifactorial threshold model of inheritance with genetic and neurodevelop mental contributions to risk. Human studies are particularly useful in capturing the richness of the phenotype, but they are often limited to the use of correlational approaches. By assessing behavioural abnormalities in both humans and rodents, nonprimate animal models of schizophrenia provide unique insight into the etiology and mechanisms of the disorder. This review discusses the phenomenology and etiology of schizophrenia and the contribution of current nonprimate animal models with an emphasis on how research with models of neuro transmitter dysregulation, environmental risk factors, neurodevelopmental disruption and genetic risk factors can complement the literature on schizophrenia in humans.
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Affiliation(s)
- Noah L Lazar
- Department of Psychology, University of Western Ontario, London, Ont.
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Nunn C, Zhao P, Zou MX, Summers K, Guglielmo CG, Chidiac P. Resistance to age-related, normal body weight gain in RGS2 deficient mice. Cell Signal 2011; 23:1375-86. [PMID: 21447383 DOI: 10.1016/j.cellsig.2011.03.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Revised: 03/01/2011] [Accepted: 03/21/2011] [Indexed: 01/09/2023]
Abstract
RGS2 (regulator of G protein signaling 2) is known to limit signals mediated via Gq- and Gs-coupled GPCRs (G protein coupled receptors), and it has been implicated in the differentiation of several cells types. The physiology of RGS2 knockout mice (rgs2(-/-)) has been studied in some detail, however, a metabolic phenotype has not previously been reported. We observed that old (21-24month) rgs2(-/-) mice weigh much less than wild-type C57BL/6 controls, and exhibit greatly reduced fat deposits, decreased serum lipids, and low leptin levels. Lower weight was evident as early as four weeks and continued throughout life. Younger adult male rgs2(-/-) mice (4-8months) were found to show similar strain-related differences as the aged animals, as well improved glucose clearance and insulin sensitivity, and enhanced beta-adrenergic and glucagon signaling in isolated hepatocytes. In addition, rgs2(-/-) pre-adipocytes had reduced levels of differentiation markers (Peroxisome proliferator-activated receptor γ (PPARγ); lipoprotein lipase (Lpl); CCAAT/enhancer binding protein α (CEBPα)) and also rgs2(-/-) white adipocytes were small relative to controls, suggesting altered adipogenesis. In wild-type animals, RGS2 mRNA was decreased in brown adipose tissue after cold exposure (7 h at 4 °C) but increased in white adipose tissue in response to a high fat diet, also suggesting a role in lipid storage. No differences between strains were detected with respect to food intake, energy expenditure, GPCR-stimulated lipolysis, or adaptive thermogenesis. In conclusion this study points to RGS2 as being an important regulatory factor in controlling body weight and adipose function.
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Affiliation(s)
- Caroline Nunn
- Department of Physiology and Pharmacology, University of Western Ontario, London, Canada
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Kaur K, Kehrl JM, Charbeneau RA, Neubig RR. RGS-insensitive Gα subunits: probes of Gα subtype-selective signaling and physiological functions of RGS proteins. Methods Mol Biol 2011; 756:75-98. [PMID: 21870221 DOI: 10.1007/978-1-61779-160-4_4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The Regulator of G protein Signaling (RGS) proteins were identified as a family in 1996 and humans have more than 30 such proteins. Their best known function is to suppress G Protein-Coupled Receptors (GPCR) signaling by increasing the rate of Gα turnoff through stimulation of GTPase activity (i.e., GTPase acceleration protein or GAP activity). The GAP activity of RGS proteins on the Gαi and Gαq family of G proteins can terminate signals initiated by both α and βγ subunits. RGS proteins also serve as scaffolds, assembling signal-regulating modules. Understanding the physiological roles of RGS proteins is of great importance, as GPCRs are major targets for drug development. The traditional method of using RGS knockout mice has provided some information about the role of RGS proteins but in many cases effects are modest, perhaps because of redundancy in RGS protein function. As an alternative approach, we have utilized a glycine-to-serine mutation in the switch 1 region of Gα subunits that prevents RGS binding. The mutation has no known effects on Gα binding to receptor, Gβγ, or effectors. Alterations in function resulting from the G>S mutation imply a role for both the specific mutated Gα subunit and its regulation by RGS protein activity. Mutant rodents expressing these G>S mutant Gα subunits have strong phenotypes and provide important information about specific physiological functions of Gαi2 and Gαo and their control by RGS. The conceptual framework behind this approach and a summary of recent results is presented in this chapter.
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Affiliation(s)
- Kuljeet Kaur
- Department of Pharmacology, The University of Michigan Medical School, Ann Arbor, MI, USA
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44
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Tiwari AK, Zai CC, Müller DJ, Kennedy JL. Genetics in schizophrenia: where are we and what next? DIALOGUES IN CLINICAL NEUROSCIENCE 2010. [PMID: 20954426 PMCID: PMC3181975 DOI: 10.31887/dcns.2010.12.3/atiwari] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Understanding the genetic basis of schizophrenia continues to be major challenge. The research done during the last two decades has provided several candidate genes which unfortunately have not been consistently replicated across or within a population. The recent genome-wide association studies (GWAS) and copy number variation (CNV) studies have provided important evidence suggesting a role of both common and rare large CNVs in schizophrenia genesis. The burden of rare copy number variations appears to be increased in schizophrenia patients. A consistent observation among the GWAS studies is the association with schizophrenia of genetic markers in the major histocompatibility complex (6p22.1)-containing genes including NOTCH4 and histone protein loci. Molecular genetic studies are also demonstrating that there is more overlap between the susceptibility genes for schizophrenia and bipolar disorder than previously suspected. In this review we summarize the major findings of the past decade and suggest areas of future research.
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Affiliation(s)
- Arun K Tiwari
- Neurogenetics section, Neuroscience department, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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45
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Sjögren B, Neubig RR. Thinking outside of the "RGS box": new approaches to therapeutic targeting of regulators of G protein signaling. Mol Pharmacol 2010; 78:550-7. [PMID: 20664002 PMCID: PMC2981398 DOI: 10.1124/mol.110.065219] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 07/22/2010] [Indexed: 11/22/2022] Open
Abstract
Regulators of G protein signaling (RGS) proteins are emerging as potentially important drug targets. The mammalian RGS protein family has more than 20 members and they share a common ∼120-residue RGS homology domain or "RGS box." RGS proteins regulate signaling via G protein-coupled receptors by accelerating GTPase activity at active α subunits of G proteins of the G(q) and G(i/o) families. Most studies searching for modulators of RGS protein function have been focused on inhibiting the GTPase accelerating protein activity. However, many RGS proteins contain additional domains that serve other functions, such as interactions with proteins or subcellular targeting. Here, we discuss a rationale for therapeutic targeting of RGS proteins by regulation of expression or allosteric modulation to permit either increases or decreases in RGS function. Several RGS proteins have reduced expression or function in pathophysiological states, so strategies to increase RGS function would be useful. Because several RGS proteins are rapidly degraded by the N-end rule pathway, finding ways to stabilize them may prove to be an effective way to enhance RGS protein function.
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Affiliation(s)
- Benita Sjögren
- Department of Pharmacology, University of Michigan, 1150 W Medical Center Dr, MSRB III, Ann Arbor, MI 48109, USA
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46
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Brain region specific actions of regulator of G protein signaling 4 oppose morphine reward and dependence but promote analgesia. Biol Psychiatry 2010; 67:761-9. [PMID: 19914603 PMCID: PMC3077672 DOI: 10.1016/j.biopsych.2009.08.041] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Revised: 07/01/2009] [Accepted: 08/19/2009] [Indexed: 11/22/2022]
Abstract
BACKGROUND Regulator of G protein signaling 4 (RGS4) is one of the smaller members of the RGS family of proteins, which are known to control signaling amplitude and duration via interactions with G protein alpha subunits or other signaling molecules. Earlier evidence suggests dynamic regulation of RGS4 levels in neuronal networks mediating actions of opiates and other drugs of abuse, but the consequences of RGS4 actions in vivo are largely unknown. METHODS In this study, we use constitutive and nucleus accumbens-inducible RGS4 knockout mice as well as mice overexpressing RGS4 in the nucleus accumbens via viral mediated gene transfer, to examine the influence of RGS4 on behavioral responses to opiates. We also use electrophysiology and immunoprecipitation assays to further understand the mechanisms underlying the tissue-specific actions of RGS4. RESULTS Inducible knockout or selective overexpression of RGS4 in the nucleus accumbens reveals that, in this brain region, RGS4 acts as a negative regulator of morphine reward, whereas in the locus coeruleus RGS4 opposes morphine physical dependence. In contrast, we show that RGS4 does not affect morphine analgesia or tolerance but is a positive modulator of certain opiate analgesics, such as methadone and fentanyl. CONCLUSIONS These findings provide fundamentally novel information concerning the role of RGS4 in the cellular mechanisms underlying the diverse actions of opiate drugs in the nervous system.
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Abstract
Regulator of G protein-signaling (RGS) proteins are a family of more than 30 intracellular proteins that negatively modulate intracellular signaling of receptors in the G protein-coupled receptor family. This family includes receptors for opioids, cannabinoids, and dopamine that mediate the acute effects of addictive drugs or behaviors and chronic effects leading to the development of addictive disease. Members of the RGS protein family, by negatively modulating receptor signaling, influence the intracellular processes that lead to addiction. In turn, addictive drugs control the expression levels of several RGS proteins. This review will consider the distribution and mechanisms of action of RGS proteins, particularly the R4 and R7 families that have been implicated in the actions of addictive drugs, how knowledge of these proteins is contributing to an understanding of addictive processes, and whether specific RGS proteins could provide targets for the development of medications to manage and/or treat addiction.
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Affiliation(s)
- John Traynor
- Department of Pharmacology and Substance Abuse Research Center, University of Michigan, Ann Arbor, Michigan 48109-5632, USA.
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48
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Mazzoncini R, Zoli M, Tosato S, Lasalvia A, Ruggeri M. Can the role of genetic factors in schizophrenia be enlightened by studies of candidate gene mutant mice behaviour? World J Biol Psychiatry 2010; 10:778-97. [PMID: 19396727 DOI: 10.1080/15622970902875152] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Schizophrenia is one of the most severe psychiatric disorders. Despite the knowledge accumulated over years, aetiology and pathophysiology remain uncertain. Research on families and twins suggests that genetic factors are largely responsible for the disease and implies specific genes as risk factors. Genetic epidemiology indicates a complex transmission mode, compatible with a multi-locus model, with single genes accounting for specific traits rather than for the entire phenotype. To better understand every single gene contribution to schizophrenia, the use of intermediate endophenotypes has been proposed. A straight communication between preclinical and clinical researchers could facilitate research on the association between genes and endophenotypes. Many behavioural tasks are available for humans and animals to measure endophenotypes. Here, firstly, we reviewed the most promising mouse behavioural tests modelling human behavioural tasks altered in schizophrenia. Secondly, we systematically reviewed animal models availability for a selection of candidate genes, derived from linkage and association studies. Thirdly, we systematically reviewed the studies which tested mutant mice in the above behavioural tasks. Results indicate a large mutant mice availability for schizophrenia candidate genes but they have been insufficiently tested in behavioural tasks. On the other hand, multivariate and translational approach should be implemented in several behavioural domains.
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Affiliation(s)
- Rodolfo Mazzoncini
- Department of Medicine and Public Health, Section of Psychiatry and Clinical Psychology, University of Verona, Verona, Italy.
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Abstract
Cognitive deficits are core features of psychiatric disorders and contribute substantially to functional outcome. It is still unclear, however, how cognitive deficits are related to underlying genetic liability and overt clinical symptoms. Fortunately, animal models of susceptibility genes can illuminate how the products of disease-associated genetic variants affect brain function and ultimately alter behavior. Using as a reference findings from the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia program and the SchizophreniaGene database, we review cognitive data from mutant models of rare and common genetic variants associated with schizophrenia.
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Affiliation(s)
- P. Alexander Arguello
- Department of Neuroscience,To whom correspondence should be addressed; tel: 1-212-305-2020, fax: 1-212-342-1801, e-mail:
| | - Joseph A. Gogos
- Department of Neuroscience,Department of Physiology and Cellular Biophysics, Columbia University Medical Center, 630 W. 168th Street, New York, NY 10032
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50
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O'Tuathaigh CMP, Kirby BP, Moran PM, Waddington JL. Mutant mouse models: genotype-phenotype relationships to negative symptoms in schizophrenia. Schizophr Bull 2010; 36:271-88. [PMID: 19934211 PMCID: PMC2833123 DOI: 10.1093/schbul/sbp125] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Negative symptoms encompass diminution in emotional expression and motivation, some of which relate to human attributes that may not be accessible readily in animals. Additionally, their refractoriness to treatment precludes therapeutic validation of putative models. This review considers critically the application of mutant mouse models to the study of the pathobiology of negative symptoms. It focuses on 4 main approaches: genes related to the pathobiology of schizophrenia, genes associated with risk for schizophrenia, neurodevelopmental-synaptic genes, and variant approaches from other areas of neurobiology. Despite rapid advances over the past several years, it is clear that we continue to face substantive challenges in applying mutant models to better understand the pathobiology of negative symptoms: the majority of evidence relates to impairments in social behavior, with only limited data relating to anhedonia and negligible data concerning avolition and other features; even for the most widely examined feature, social behavior, studies have used diverse assessments thereof; modelling must proceed in cognizance of increasing evidence that genes and pathobiologies implicated in schizophrenia overlap with other psychotic disorders, particularly bipolar disorder. Despite the caveats and challenges, several mutant lines evidence a phenotype for at least one index of social behavior. Though this may suggest superficially some shared relationship to negative symptoms, it is not yet possible to specify either the scope or the pathobiology of that relationship for any given gene. The breadth and depth of ongoing studies in mutants hold the prospect of addressing these shortcomings.
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Affiliation(s)
- Colm M. P. O'Tuathaigh
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, St Stephen's Green, Dublin 2, Ireland,To whom correspondence should be addressed; tel: +353-1-402-2377, fax: +353-1-402-2453, e-mail:
| | - Brian P. Kirby
- School of Pharmacy, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Paula M. Moran
- School of Psychology, University of Nottingham, Nottingham, UK
| | - John L. Waddington
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, St Stephen's Green, Dublin 2, Ireland
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