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Zhang Q, Sjögren B. Palmitoylation of RGS20 affects Gα o-mediated signaling independent of its GAP activity. Cell Signal 2023; 107:110682. [PMID: 37075876 DOI: 10.1016/j.cellsig.2023.110682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 04/07/2023] [Accepted: 04/15/2023] [Indexed: 04/21/2023]
Abstract
Regulator of protein signaling (RGS20) is a member of the RGS protein superfamily, which serve as key negative regulators of G protein-mediated signal transduction. Through their GTPase accelerating protein (GAP) activity, RGS proteins deactivate α-subunits of heterotrimeric G proteins. In addition, the majority of RGS proteins also have the ability to act through other, non-GAP related, functions. RGS20 is one of three members of the RZ subfamily, which all show selective GAP activity towards Gαz, however emerging data suggest that RGS20 can also regulate Gi/o-mediated signaling. While increased RGS20 expression is associated with the progression of multiple cancers, a large gap still exists relating to the mechanisms of RGS20 regulation and function. RGS20 contains a poly-cysteine string motif and a conserved cysteine in RGS domain, which are assumed to be palmitoylated. Palmitoylation, an important post-translational modification, plays an important role in cells by changing cellular functions of proteins. Consequently, the aim of this study was to confirm that RGS20 is palmitoylated and determine how palmitoylation affects its inhibition of Gαo-mediated signaling. We found a significant positive correlation between RGS20 palmitoylation and its association with active Gαo. We also showed that a conserved cysteine residue in the RGS domain is a critical site for its palmitoylation, with large impact on its association with Gαo. Palmitoylation on this site did not affect its GAP activity, however, it increased the inhibition of Gαo-mediated cAMP signaling. Altogether these data suggest that palmitoylation is a regulatory mechanism controlling RGS20 function, and that RGS20 can inhibit Gαo signaling through both GAP activity and non-GAP mechanisms.
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Affiliation(s)
- Qian Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, United States of America
| | - Benita Sjögren
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, United States of America.
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2
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Williams AV, Peña CJ, Ramos-Maciel S, Laman-Maharg A, Ordoñez-Sanchez E, Britton M, Durbin-Johnson B, Settles M, Hao R, Yokoyama S, Xu C, Luo PX, Dwyer T, Bhela S, Black AM, Labonté B, Serafini RA, Ruiz A, Neve RL, Zachariou V, Nestler EJ, Trainor BC. Comparative Transcriptional Analyses in the Nucleus Accumbens Identifies RGS2 as a Key Mediator of Depression-Related Behavior. Biol Psychiatry 2022; 92:942-951. [PMID: 36075764 PMCID: PMC9794384 DOI: 10.1016/j.biopsych.2022.06.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/21/2022] [Accepted: 06/22/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND Major depressive disorder is one of the most commonly diagnosed mental illnesses worldwide, with a higher prevalence in women than in men. Although currently available pharmacological therapeutics help many individuals, they are not effective for most. Animal models have been important for the discovery of molecular alterations in stress and depression, but difficulties in adapting animal models of depression for females has impeded progress in developing novel therapeutic treatments that may be more efficacious for women. METHODS Using the California mouse social defeat model, we took a multidisciplinary approach to identify stress-sensitive molecular targets that have translational relevance for women. We determined the impact of stress on transcriptional profiles in male and female California mouse nucleus accumbens (NAc) and compared these results with data from postmortem samples of the NAc from men and women diagnosed with major depressive disorder. RESULTS Our cross-species computational analyses identified Rgs2 (regulator of G protein signaling 2) as a transcript downregulated by social defeat stress in female California mice and in women with major depressive disorder. RGS2 plays a key role in signal regulation of neuropeptide and neurotransmitter receptors. Viral vector-mediated overexpression of Rgs2 in the NAc restored social approach and sucrose preference in stressed female California mice. CONCLUSIONS These studies show that Rgs2 acting in the NAc has functional properties that translate to changes in anxiety- and depression-related behavior. Future studies should investigate whether targeting Rgs2 represents a novel target for treatment-resistant depression in women.
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Affiliation(s)
- Alexia V Williams
- Department of Psychology, University of California, Davis, Davis, California
| | - Catherine J Peña
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York; Princeton Neuroscience Institute, Princeton, New Jersey
| | | | | | - Evelyn Ordoñez-Sanchez
- Department of Psychology, University of California, Davis, Davis, California; Department of Psychology, Temple University, Philadelphia, Pennsylvania
| | - Monica Britton
- Bioinformatics Core Facility, UC Davis Genome Center, University of California, Davis, Davis, California
| | | | - Matt Settles
- Bioinformatics Core Facility, UC Davis Genome Center, University of California, Davis, Davis, California
| | - Rebecca Hao
- Department of Psychology, University of California, Davis, Davis, California
| | - Sae Yokoyama
- Department of Psychology, University of California, Davis, Davis, California
| | - Christine Xu
- Department of Psychology, University of California, Davis, Davis, California
| | - Pei X Luo
- Department of Psychology, University of California, Davis, Davis, California
| | - Tjien Dwyer
- Department of Psychology, University of California, Davis, Davis, California
| | - Shanu Bhela
- Department of Psychology, University of California, Davis, Davis, California
| | - Alexis M Black
- Department of Psychology, University of California, Davis, Davis, California
| | - Benoit Labonté
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Psychiatry and Neuroscience, Laval University, Québec, Quebec, Canada
| | - Randal Alex Serafini
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Anne Ruiz
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Rachael L Neve
- Gene Delivery Technology Core, Massachusetts General Hospital, Boston, Massachusetts
| | - Venetia Zachariou
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Eric J Nestler
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Brian C Trainor
- Department of Psychology, University of California, Davis, Davis, California.
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3
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Regulator of G protein signaling 2 inhibits Gα q-dependent uveal melanoma cell growth. J Biol Chem 2022; 298:101955. [PMID: 35452684 PMCID: PMC9120238 DOI: 10.1016/j.jbc.2022.101955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 04/06/2022] [Accepted: 04/07/2022] [Indexed: 12/23/2022] Open
Abstract
Activating mutations in Gαq/11 are a major driver of uveal melanoma (UM), the most common intraocular cancer in adults. While progress has recently been made in targeting Gαq/11 for UM therapy, the crucial role for these proteins in normal physiology and their high structural similarity with many other important GTPase proteins renders this approach challenging. The aim of the current study was to validate whether a key regulator of Gq signaling, regulator of G protein signaling 2 (RGS2), can inhibit Gαq-mediated UM cell growth. We used two UM cell lines, 92.1 and Mel-202, which both contain the most common activating mutation GαqQ209L and developed stable cell lines with doxycycline-inducible RGS2 protein expression. Using cell viability assays, we showed that RGS2 could inhibit cell growth in both of these UM cell lines. We also found that this effect was independent of the canonical GTPase-activating protein activity of RGS2 but was dependent on the association between RGS2 and Gαq. Furthermore, RGS2 induction resulted in only partial reduction in cell growth as compared to siRNA-mediated Gαq knockdown, perhaps because RGS2 was only able to reduce mitogen-activated protein kinase signaling downstream of phospholipase Cβ, while leaving activation of the Hippo signaling mediators yes-associated protein 1/TAZ, the other major pathway downstream of Gαq, unaffected. Taken together, our data indicate that RGS2 can inhibit UM cancer cell growth by associating with GαqQ209L as a partial effector antagonist.
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Roles of Cullin-RING Ubiquitin Ligases in Cardiovascular Diseases. Biomolecules 2022; 12:biom12030416. [PMID: 35327608 PMCID: PMC8946067 DOI: 10.3390/biom12030416] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 12/18/2022] Open
Abstract
Maintenance of protein homeostasis is crucial for virtually every aspect of eukaryotic biology. The ubiquitin-proteasome system (UPS) represents a highly regulated quality control machinery that protects cells from a variety of stress conditions as well as toxic proteins. A large body of evidence has shown that UPS dysfunction contributes to the pathogenesis of cardiovascular diseases. This review highlights the latest findings regarding the physiological and pathological roles of cullin-RING ubiquitin ligases (CRLs), an essential player in the UPS, in the cardiovascular system. To inspire potential therapeutic invention, factors regulating CRL activities are also discussed.
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Phan HTN, Kim NH, Wei W, Tall GG, Smrcka AV. Uveal melanoma-associated mutations in PLCβ4 are constitutively activating and promote melanocyte proliferation and tumorigenesis. Sci Signal 2021; 14:eabj4243. [PMID: 34905385 DOI: 10.1126/scisignal.abj4243] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Hoa T N Phan
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nam Hoon Kim
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Wenhui Wei
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gregory G Tall
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alan V Smrcka
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
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McNabb HJ, Gonzalez S, Muli CS, Sjögren B. N-Terminal Targeting of Regulator of G Protein Signaling Protein 2 for F-Box Only Protein 44-Mediated Proteasomal Degradation. Mol Pharmacol 2020; 98:677-685. [PMID: 33008920 DOI: 10.1124/molpharm.120.000061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 09/17/2020] [Indexed: 12/28/2022] Open
Abstract
Regulator of G protein signaling (RGS) proteins are negative modulators of G protein signaling that have emerged as promising drug targets to improve specificity and reduce side effects of G protein-coupled receptor-related therapies. Several small molecule RGS protein inhibitors have been identified; however, enhancing RGS protein function is often more clinically desirable but presents a challenge. Low protein levels of RGS2 are associated with various pathologies, including hypertension and heart failure. For this reason, RGS2 is a prominent example wherein enhancing its function would be beneficial. RGS2 is rapidly ubiquitinated and proteasomally degraded, providing a point of intervention for small molecule RGS2-stabilizing compounds. We previously identified a novel cullin-RING E3 ligase utilizing F-box only protein 44 (FBXO44) as the substrate recognition component. Here, we demonstrate that RGS2 associates with FBXO44 through a stretch of residues in its N terminus. RGS2 contains four methionine residues close to the N terminus that can act as alternative translation initiation sites. The shorter translation initiation variants display reduced ubiquitination and proteasomal degradation as a result of lost association with FBXO44. In addition, we show that phosphorylation of Ser3 may be an additional mechanism to protect RGS2 from FBXO44-mediated proteasomal degradation. These findings contribute to elucidating mechanisms regulating steady state levels of RGS2 protein and will inform future studies to develop small molecule RGS2 stabilizers. These would serve as novel leads in pathologies associated with low RGS2 protein levels, such as hypertension, heart failure, and anxiety. SIGNIFICANCE STATEMENT: E3 ligases provide a novel point of intervention for therapeutic development, but progress is hindered by the lack of available information about specific E3-substrate pairs. Here, we provide molecular detail on the recognition of regulator of G protein signaling protein 2 (RGS2) by its E3 ligase, increasing the potential for rational design of small molecule RGS2 protein stabilizers. These would be clinically useful in pathologies associated with low RGS2 protein levels, such as hypertension, heart failure, and anxiety.
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Affiliation(s)
- Harrison J McNabb
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Stephanie Gonzalez
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Christine S Muli
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Benita Sjögren
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
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McNabb HJ, Zhang Q, Sjögren B. Emerging Roles for Regulator of G Protein Signaling 2 in (Patho)physiology. Mol Pharmacol 2020; 98:751-760. [PMID: 32973086 DOI: 10.1124/molpharm.120.000111] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 09/08/2020] [Indexed: 12/11/2022] Open
Abstract
Since their discovery in the mid-1990s, regulator of G protein signaling (RGS) proteins have emerged as key regulators of signaling through G protein-coupled receptors. Among the over 20 known RGS proteins, RGS2 has received increasing interest as a potential therapeutic drug target with broad clinical implications. RGS2 is a member of the R4 subfamily of RGS proteins and is unique in that it is selective for Gα q Despite only having an RGS domain, responsible for the canonical GTPase activating protein activity, RGS2 can regulate additional processes, such as protein synthesis and adenylate cyclase activity, through protein-protein interactions. Here we provide an update of the current knowledge of RGS2 function as it relates to molecular mechanisms of regulation as well as its potential role in regulating a number of physiologic systems and pathologies, including cardiovascular disease and central nervous system disorders, as well as various forms of cancer. SIGNIFICANCE STATEMENT: Regulator of G protein signaling (RGS) proteins represent an exciting class of novel drug targets. RGS2, in particular, could have broad clinical importance. As more details are emerging on the regulation of RGS2 in various physiological systems, the potential utility of this small protein in therapeutic development is increasing.
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Affiliation(s)
- Harrison J McNabb
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Qian Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Benita Sjögren
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
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Hüttl M, Markova I, Miklankova D, Makovicky P, Pelikanova T, Šeda O, Šedová L, Malinska H. Adverse Effects of Methylglyoxal on Transcriptome and Metabolic Changes in Visceral Adipose Tissue in a Prediabetic Rat Model. Antioxidants (Basel) 2020; 9:antiox9090803. [PMID: 32878255 PMCID: PMC7555565 DOI: 10.3390/antiox9090803] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 12/12/2022] Open
Abstract
Excessive methylglyoxal (MG) production contributes to metabolic and vascular changes by increasing inflammatory processes, disturbing regulatory mechanisms and exacerbating tissue dysfunction. MG accumulation in adipocytes leads to structural and functional changes. We used transcriptome analysis to investigate the effect of MG on metabolic changes in the visceral adipose tissue of hereditary hypetriglyceridaemic rats, a non-obese model of metabolic syndrome. Compared to controls, 4-week intragastric MG administration impaired glucose tolerance (p < 0.05) and increased glycaemia (p < 0.01) and serum levels of MCP-1 and TNFα (p < 0.05), but had no effect on serum adiponectin or leptin. Adipose tissue insulin sensitivity and lipolysis were impaired (p < 0.05) in MG-treated rats. In addition, MG reduced the expression of transcription factor Nrf2 (p < 0.01), which controls antioxidant and lipogenic genes. Increased expression of Mcp-1 and TNFα (p < 0.05) together with activation of the SAPK/JNK signaling pathway can promote chronic inflammation in adipose tissue. Transcriptome network analysis revealed the over-representation of genes involved in insulin signaling (Irs1, Igf2, Ide), lipid metabolism (Nr1d1, Lpin1, Lrpap1) and angiogenesis (Dusp10, Tp53inp1).
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Affiliation(s)
- Martina Hüttl
- Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, 140 21 Prague, Czech Republic; (M.H.); (I.M.); (D.M.)
| | - Irena Markova
- Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, 140 21 Prague, Czech Republic; (M.H.); (I.M.); (D.M.)
| | - Denisa Miklankova
- Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, 140 21 Prague, Czech Republic; (M.H.); (I.M.); (D.M.)
| | - Pavol Makovicky
- Faculty of Education, Department of Biology, J. Selye University, 94501 Komarno, Slovakia;
| | - Terezie Pelikanova
- Diabetes Centre, Institute for Clinical and Experimental Medicine, 140 21 Prague, Czech Republic;
| | - Ondrej Šeda
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, 121 08 Prague, Czech Republic; (O.Š.); (L.Š.)
| | - Lucie Šedová
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, 121 08 Prague, Czech Republic; (O.Š.); (L.Š.)
| | - Hana Malinska
- Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, 140 21 Prague, Czech Republic; (M.H.); (I.M.); (D.M.)
- Correspondence: ; Tel.: +420-261-365-369; Fax: +420-261-363-027
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9
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Phan HTN, Jackson WF, Shaw VS, Watts SW, Neubig RR. Loss-of-Function Mutations in Human Regulator of G Protein Signaling RGS2 Differentially Regulate Pharmacological Reactivity of Resistance Vasculature. Mol Pharmacol 2019; 96:826-834. [PMID: 31645376 DOI: 10.1124/mol.119.116822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 10/03/2019] [Indexed: 12/21/2022] Open
Abstract
Regulator of G protein signaling 2 (RGS2) plays a role in reducing vascular contraction and promoting relaxation due to its GTPase accelerating protein activity toward Gαq. Previously, we identified four human loss-of-function (LOF) mutations in RGS2 (Q2L, D40Y, R44H, and R188H). This study aimed to investigate whether those RGS2 LOF mutations disrupt the ability of RGS2 to regulate vascular reactivity. Isolated mesenteric arteries (MAs) from RGS2-/- mice showed an elevated contractile response to 5 nM angiotensin II and a loss of acetylcholine (ACh)-mediated vasodilation. Reintroduction of a wild-type (WT) RGS2-GFP plasmid into RGS2-/- MAs suppressed the vasoconstrictor response to angiotensin II. RGS2 LOF mutants failed to suppress the angiotensin II constriction response compared with RGS2 WT. In contrast, ACh-mediated vasoconstriction was restored by expression of RGS2 WT, D40Y, and R44H but not by RGS2 Q2L or R188H. Phosphorylation of RGS2 D40Y and R44H by protein kinase G (PKG) may explain their maintained function to support relaxation in MAs. This is supported by phosphomimetic mutants and suppression of vasorelaxation mediated by RGS2 D40Y by a PKG inhibitor. These results demonstrate that RGS2 attenuates vasoconstriction in MAs and that RGS2 LOF mutations cannot carry out this effect. Among them, the Q2L and R188H mutants supported less relaxation to ACh, whereas relaxation mediated by the D40Y and R44H mutant proteins was equal to that with WT protein. Phosphorylation of RGS2 by PKG appears to contribute to this vasorelaxation. These results provide insights for precision medicine targeting the rare individuals carrying these RGS2 mutations. SIGNIFICANCE STATEMENT: Regulator of G protein signaling 2 (RGS2) has been implicated in the control of blood pressure; rare mutations in the RGS2 gene have been identified in large-scale human gene sequencing studies. Four human mutations in RGS2 that cause loss of function (LOF) in cell-based assays were examined in isolated mouse arteries for effects on both vasoconstriction and vasodilation. All mutants showed the expected LOF effects in suppressing vasoconstriction. Surprisingly, the D40Y and R44H mutant RGS2 showed normal control of vasodilation. We propose that this is due to rescue of the mislocalization phenotype of these two mutants by nitric oxide-mediated/protein kinase G-dependent phosphorylation. These mechanisms may guide drug discovery or drug repurposing efforts for hypertension by enhancing RGS2 function.
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Affiliation(s)
- Hoa T N Phan
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (H.T.N.P., W.F.J., V.S.S., S.W.W., R.R.N.)
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (H.T.N.P., W.F.J., V.S.S., S.W.W., R.R.N.)
| | - Vincent S Shaw
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (H.T.N.P., W.F.J., V.S.S., S.W.W., R.R.N.)
| | - Stephanie W Watts
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (H.T.N.P., W.F.J., V.S.S., S.W.W., R.R.N.)
| | - Richard R Neubig
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (H.T.N.P., W.F.J., V.S.S., S.W.W., R.R.N.)
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Kruit AS, Smits L, Pouwels A, Schreinemachers MCJM, Hummelink SLM, Ulrich DJO. Ex-vivo perfusion as a successful strategy for reduction of ischemia-reperfusion injury in prolonged muscle flap preservation - A gene expression study. Gene 2019; 701:89-97. [PMID: 30902788 DOI: 10.1016/j.gene.2019.03.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 03/10/2019] [Accepted: 03/12/2019] [Indexed: 11/18/2022]
Abstract
INTRODUCTION With the introduction of vascularized composite allotransplantation (VCA) as new surgical technique, the need arose for strategies that could safely prolong graft preservation. Ex-vivo machine perfusion is a promising technique and is currently applied in solid organ transplantation. There is still limited evidence in the field of VCA and free flap transplantation. This gene expression study aimed to assess the degree of ischemia-reperfusion (IR) injury after preservation and replantation of free muscle flaps in a porcine model. MATERIALS AND METHODS A microarray analysis was first conducted on muscle flaps preserved by ex-vivo perfusion versus cold storage, to select genes of interest for further investigation. The expression of these selected genes was then examined in a muscle flap replantation model after 18 hour ex-vivo perfusion (n = 14) using qRT-PCR. Two preservation solutions were compared to static cold storage: University of Wisconsin-mp (n = 5) and Histidine-Tryptophan-Ketoglutarate solution (n = 5). RESULTS A selection of 8 genes was made based on micro-array results: Tumor necrosis factor receptor superfamily member 10-A like, Regulator of G-protein signaling 2, Nuclear factor kappa beta inhibitor zeta, Interleukin-1 beta, Fibroblast growth factor 6 and DNA damage-inducible transcript 4, Hypoxia-inducible factor 1-alpha and Caspase-3. The muscle flap replantation experiment compared their expression patterns before and after preservation and replantation and showed overall comparable gene expression between the preservation groups. CONCLUSIONS The expression of genes related to ischemia, apoptosis and inflammation was comparable between the ex-vivo perfusion and static cold storage groups. These results suggest that ex-vivo perfusion might be a promising technique for 18 hour muscle preservation in terms of decreasing ischemia-reperfusion injury.
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Affiliation(s)
- Anne Sophie Kruit
- Department of Plastic, Reconstructive and Hand Surgery, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Laura Smits
- Medical Biology, Faculty of Science, Radboud University, Nijmegen, the Netherlands
| | - Angéle Pouwels
- HAN University of Applied Sciences, Nijmegen, the Netherlands
| | | | - Stefan L M Hummelink
- Department of Plastic, Reconstructive and Hand Surgery, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Dietmar J O Ulrich
- Department of Plastic, Reconstructive and Hand Surgery, Radboud University Medical Center, Nijmegen, the Netherlands
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Squires KE, Montañez-Miranda C, Pandya RR, Torres MP, Hepler JR. Genetic Analysis of Rare Human Variants of Regulators of G Protein Signaling Proteins and Their Role in Human Physiology and Disease. Pharmacol Rev 2018; 70:446-474. [PMID: 29871944 DOI: 10.1124/pr.117.015354] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Regulators of G protein signaling (RGS) proteins modulate the physiologic actions of many neurotransmitters, hormones, and other signaling molecules. Human RGS proteins comprise a family of 20 canonical proteins that bind directly to G protein-coupled receptors/G protein complexes to limit the lifetime of their signaling events, which regulate all aspects of cell and organ physiology. Genetic variations account for diverse human traits and individual predispositions to disease. RGS proteins contribute to many complex polygenic human traits and pathologies such as hypertension, atherosclerosis, schizophrenia, depression, addiction, cancers, and many others. Recent analysis indicates that most human diseases are due to extremely rare genetic variants. In this study, we summarize physiologic roles for RGS proteins and links to human diseases/traits and report rare variants found within each human RGS protein exome sequence derived from global population studies. Each RGS sequence is analyzed using recently described bioinformatics and proteomic tools for measures of missense tolerance ratio paired with combined annotation-dependent depletion scores, and protein post-translational modification (PTM) alignment cluster analysis. We highlight selected variants within the well-studied RGS domain that likely disrupt RGS protein functions and provide comprehensive variant and PTM data for each RGS protein for future study. We propose that rare variants in functionally sensitive regions of RGS proteins confer profound change-of-function phenotypes that may contribute, in newly appreciated ways, to complex human diseases and/or traits. This information provides investigators with a valuable database to explore variation in RGS protein function, and for targeting RGS proteins as future therapeutic targets.
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Affiliation(s)
- Katherine E Squires
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Carolina Montañez-Miranda
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Rushika R Pandya
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Matthew P Torres
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - John R Hepler
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
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