51
|
Zhang X, Chen S, Chen H, Pan H, Zhao Y. Inhibition of β-ARK1 Ameliorates Morphine-induced Tolerance and Hyperalgesia Via Modulating the Activity of Spinal NMDA Receptors. Mol Neurobiol 2017; 55:5393-5407. [DOI: 10.1007/s12035-017-0780-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 09/19/2017] [Indexed: 02/02/2023]
|
52
|
Chiu YT, Chen C, Yu D, Schulz S, Liu-Chen LY. Agonist-Dependent and -Independent κ Opioid Receptor Phosphorylation: Distinct Phosphorylation Patterns and Different Cellular Outcomes. Mol Pharmacol 2017; 92:588-600. [PMID: 28893975 DOI: 10.1124/mol.117.108555] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 08/10/2017] [Indexed: 01/21/2023] Open
Abstract
We reported previously that the selective agonist U50,488H promoted phosphorylation of the mouse κ opioid receptor (KOPR) at residues S356, T357, T363, and S369. Here, we found that agonist (U50,488H)-dependent KOPR phosphorylation at all the residues was mediated by Gi/o α proteins and multiple protein kinases [GRK2, GRK3, GRK5, GRK6 and protein kinase C (PKC)]. In addition, PKC activation by phorbol ester induced agonist-independent KOPR phosphorylation. Compared with U50,488H, PKC activation promoted much higher S356/T357 phosphorylation, much lower T363 phosphorylation, and similar levels of S369 phosphorylation. After U50,488H treatment, GRKs, but not PKC, were involved in agonist-induced KOPR internalization. In contrast, PKC activation caused a lower level of agonist-independent KOPR internalization, compared with U50,488H. U50,488H-induced activation of extracellular signal-regulated kinase 1/2 (ERK1/2) was G protein-, but not β-arrestin-, dependent. After U50,488H treatment, GRK-mediated, but not PKC-mediated, KOPR phosphorylation followed by β-arrestin recruitment desensitized U50,488H-induced ERK1/2 response. Therefore, agonist-dependent (GRK- and PKC-mediated) and agonist-independent (PKC-promoted) KOPR phosphorylations show distinct phosphorylation patterns, leading to diverse cellular outcomes.
Collapse
Affiliation(s)
- Yi-Ting Chiu
- Center for Substance Abuse Research and Department of Pharmacology (Y.-T.C., C.C., L.-Y.L.-C.) and Department of Clinical Sciences (D.Y.), Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania; and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (S.S.)
| | - Chongguang Chen
- Center for Substance Abuse Research and Department of Pharmacology (Y.-T.C., C.C., L.-Y.L.-C.) and Department of Clinical Sciences (D.Y.), Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania; and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (S.S.)
| | - Daohai Yu
- Center for Substance Abuse Research and Department of Pharmacology (Y.-T.C., C.C., L.-Y.L.-C.) and Department of Clinical Sciences (D.Y.), Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania; and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (S.S.)
| | - Stefan Schulz
- Center for Substance Abuse Research and Department of Pharmacology (Y.-T.C., C.C., L.-Y.L.-C.) and Department of Clinical Sciences (D.Y.), Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania; and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (S.S.)
| | - Lee-Yuan Liu-Chen
- Center for Substance Abuse Research and Department of Pharmacology (Y.-T.C., C.C., L.-Y.L.-C.) and Department of Clinical Sciences (D.Y.), Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania; and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany (S.S.)
| |
Collapse
|
53
|
Impact of paroxetine on proximal β-adrenergic receptor signaling. Cell Signal 2017; 38:127-133. [PMID: 28711716 DOI: 10.1016/j.cellsig.2017.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 07/10/2017] [Indexed: 11/21/2022]
Abstract
β-adrenergic receptors (βAR) regulate numerous functions throughout the body, however G protein-coupled receptor kinase (GRK)-dependent desensitization of βAR has long been recognized as a maladaptive process in the progression of various disease states. Thus, the development of small molecule inhibitors of GRKs for the study of these processes and as potential therapeutics has been at the forefront of recent research efforts. Via structural and biochemical analyses, the selective serotonin reuptake inhibitor (SSRI) paroxetine was identified as a GRK2 inhibitor that enhances βAR-dependent cardiomyocyte and cardiac contractility and reverses cardiac dysfunction and myocardial βAR expression in mouse models of heart failure. Despite these functional outcomes, consistent with diminished βAR desensitization, the proximal βAR signaling mechanisms sensitive to paroxetine have not been reported. In this study, we aimed to determine whether paroxetine prevents classic βAR desensitization-related signaling mechanisms at a molecular level. Therefore, via immunoblotting, radioligand binding, fluorescence resonance energy transfer (FRET) and microscopy assays, we have performed an assessment of the effect of paroxetine on proximal βAR signaling responses. Indeed, paroxetine treatment inhibited ligand-induced β2AR phosphorylation in a concentration-dependent manner. Additionally, for both β1AR and β2AR, paroxetine decreased ligand-induced βarrestin2 recruitment and subsequent receptor internalization. Thus, paroxetine inhibits βAR desensitization mechanisms consistent with GRK2 inhibition and provides a useful pharmacological tool for studying these proximal GPCR signaling responses.
Collapse
|
54
|
Jin Y, Liang ZY, Zhou WX, Zhou L. Expression and Significances of G-Protein-Coupled Receptor Kinase 3 in Hepatocellular Carcinoma. J Cancer 2017; 8:1972-1978. [PMID: 28819396 PMCID: PMC5559957 DOI: 10.7150/jca.19201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 04/30/2017] [Indexed: 12/15/2022] Open
Abstract
Objective: To investigate expression, clinical, pathologic and prognostic significances of G-protein-coupled receptor kinase 3 (GRK3) in hepatocellular carcinoma (HCC). Materials and Methods: Expression of GRK3 was detected using Western blotting and tissue microarray-based immunohistochemical staining in 8 and 395 patients (training set: n=164; validation set: n=231) with HCC underwent hepatectomy, respectively. GRK3 expression and its associations with cliniopathologic variables and tumor-specific survival were evaluated. Results: Expression of GRK3 was lower in tumor than in non-tumor tissues from 4 out of 8 patients. In the training set, the H-score of tumoral GRK3 staining was much lower than that in adjacent non-tumor liver tissues. In addition, GRK3 was associated with tumor-node-metastasis (TNM) stage and serum α-fetoprotein (AFP) level. Patients with high GRK3 tumors were found to carry significantly better tumor-specific survival, compared with those with low GRK3 ones. Furthermore, GRK3 was identified as one of independent predictors of favorable prognosis, adjusted for clinicopathologic parameters. Importantly, these results were further validated in the independent validation set. In all patients and 7 out of 10 subgroups, GRK3 was also revealed to be prognostic. Conclusions: GRK3 is down-regulated and predicts good prognosis in HCC. Therefore, GRK3 might function as a tumor suppressor gene in HCC.
Collapse
Affiliation(s)
- Ye Jin
- Clinical Research Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences/Peking Union Medical College, Beijing 100730, China
| | - Zhi-Yong Liang
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences/Peking Union Medical College, Beijing 100730, China
| | - Wei-Xun Zhou
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences/Peking Union Medical College, Beijing 100730, China
| | - Li Zhou
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences/Peking Union Medical College, Beijing 100730, China
| |
Collapse
|
55
|
Park JJ, Seong HK, Kim JS, Munkhzaya B, Kang MH, Min KS. Internalization of Rat FSH and LH/CG Receptors by rec-eCG in CHO-K1 Cells. Dev Reprod 2017; 21:111-120. [PMID: 28791335 PMCID: PMC5532303 DOI: 10.12717/dr.2017.21.2.111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 03/23/2017] [Accepted: 03/25/2017] [Indexed: 11/17/2022]
Abstract
Equine chorionic gonadotropin (eCG) is a unique molecule that elicits the response characteristics of both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in other species. Previous studies from this laboratory had demonstrated that recombinant eCG (rec-eCG) from Chinese hamster ovary (CHO-K1) cells exhibited both FSH- and LH-like activity in rat granulosa and Leydig cells. In this study, we analyzed receptor internalization through rec-eCGs, wild type eCG (eCGβ/α) and mutant eCG (eCGβ/αΔ56) with an N-linked oligosaccharide at Asn56 of the α-subunit. Both the rec-eCGs were obtained from CHO-K1 cells. The agonist activation of receptors was analyzed by measuring stimulation time and concentrations of rec-eCGs. Internalization values in the stably selected rat follicle-stimulating hormone receptor (rFSHR) and rat luteinizing/chorionic gonadotropin receptor (rLH/CGR) were highest at 50 min after stimulation with 10 ng of rec-eCGβ/α. The dose-dependent response was highest when 10 ng of rec-eCGβ/α was used. The deglycosylated eCGβ/αΔ56 mutant did not enhance the agonist-stimulated internalization. We concluded that the state of activation of rFSHR and rLH/CGR could be modulated through agonist-stimulated internalization. Our results suggested that the eLH/CGRs are mostly internalized within 60 min by agonist-stimulation by rec-eCG. We also suggested that the lack of responsiveness of the deglycosylated eCGβ/ αΔ56 was likely because the site of glycosylation played a pivotal role in agonist-stimulated internalization in cells expressing rFSHR and rLH/CGR.
Collapse
Affiliation(s)
- Jong-Ju Park
- Animal Biotechnology, Graduate School of Future Convergence Technology, Department of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| | - Hun-Ki Seong
- Animal Biotechnology, Graduate School of Future Convergence Technology, Department of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| | - Jeong-Soo Kim
- Animal Biotechnology, Graduate School of Future Convergence Technology, Department of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| | - Byambaragchaa Munkhzaya
- Animal Biotechnology, Graduate School of Future Convergence Technology, Department of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| | - Myung-Hwa Kang
- Department of Food Science and Nutrition, Hoseo University, Asan 31499, Korea
| | - Kwan-Sik Min
- Animal Biotechnology, Graduate School of Future Convergence Technology, Department of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| |
Collapse
|
56
|
Shimizu Y, Koyama R, Kawamoto T. Rho kinase-dependent desensitization of GPR39; a unique mechanism of GPCR downregulation. Biochem Pharmacol 2017; 140:105-114. [PMID: 28619258 DOI: 10.1016/j.bcp.2017.06.115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 06/09/2017] [Indexed: 12/14/2022]
Abstract
GPR39, a G-protein-coupled receptor activated by zinc, reportedly activates multiple intracellular signaling pathways via Gs, Gq, G12/13, and β-arrestin, but little is known about downregulation of the receptor upon its activation. To our knowledge, this is the first report on the mechanism of feedback regulation of GPR39 function determined in GPR39-expressing HEK293 cells (HEK293-GPR39) as a model cell system. In HEK293-GPR39 cells, GPR39-C3, which is a positive allosteric modulator, activated cAMP production (downstream of Gs), IP1 accumulation (downstream of Gq), SRF-RE-dependent transcription (downstream of G12/13), and β-arrestin recruitment. GPR39-C3 induced dose- and time-dependent loss of response in cAMP production by second challenge of the compound. This functional desensitization was blocked by the Rho kinase (ROCK) inhibitor, Y-27632, but not by Gq or Gs-pathway inhibitors or inhibition of β-arrestin recruitment. In the receptor localization assay, GPR39-C3 induced internalization of GFP-tagged GPR39. This internalization was also inhibited by Y-27632, which suggested that ROCK activation is critical for internalization and desensitization of GPR39. A novel biased GPR39 positive allosteric modulator, 5-[2-[(2,4-dichlorophenyl)methoxy]phenyl]-2,2-dimethyl-1,3,5,6-tetrahydrobenzo[a]phenanthridin-4-one (GSB-118), which activated cAMP responses and β-arrestin recruitment but showed no effect on SRF-RE-dependent transcription, did not induce desensitization. These results revealed a unique mechanism of desensitization of GPR39.
Collapse
Affiliation(s)
- Yuji Shimizu
- Biomolecular Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan.
| | - Ryokichi Koyama
- Biomolecular Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Tomohiro Kawamoto
- Biomolecular Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| |
Collapse
|
57
|
Mohammad Ahmadi Soleimani S, Azizi H, Pachenari N, Mirnajafi-Zadeh J, Semnanian S. Enhancement of μ-opioid receptor desensitization by orexin-A in rat locus coeruleus neurons. Neuropeptides 2017; 63:28-36. [PMID: 28385341 DOI: 10.1016/j.npep.2017.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 03/05/2017] [Accepted: 03/22/2017] [Indexed: 11/16/2022]
Abstract
Opioids have always been used in clinical practice for pain management. However, development of tolerance to their effects following long term administration, seriously restricts further clinical use of these drugs. In this regard, μ-opioid receptor (MOR) desensitization, as an initial step in development of opioid tolerance, is of particular significance. Previous studies support the involvement of orexinergic system in development of opioid tolerance. Locus coeruleus (LC) nucleus has been shown to modulate pain and development of tolerance. Opioid receptors (particularly μ) are densely expressed within the LC. Moreover, it receives widespread orexinergic inputs and orexin type 1 receptors (OX1Rs) are also highly expressed in this brain region. In the present study, the effect of orexin-A (OXA) on met-enkephalin (ME)-induced MOR desensitization was investigated in locus coeruleus neurons of male Wistar rats (2-3weeks of age). ME (30μM), as a potent MOR agonist, was applied for 10min and the outward K+ current was recorded using whole cell patch clamp recording. The percentage of decrease in ME-induced K+ current was considered as the degree of MOR desensitization. Results indicated that OXA (100nM) enhances ME-induced MOR desensitization via affecting OX1Rs in rat locus coeruleus neurons and this effect is mediated by a protein kinase C dependent mechanism within the LC. The activity of orexinergic system might potentiate the signaling pathways underlying opioid-induced receptor desensitization.
Collapse
Affiliation(s)
| | - Hossein Azizi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
| | - Narges Pachenari
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Saeed Semnanian
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran.
| |
Collapse
|
58
|
Shimizu Y, Nakayama M. Discovery of Novel Gq-Biased LPA1 Negative Allosteric Modulators. SLAS DISCOVERY 2017; 22:859-866. [PMID: 28346103 DOI: 10.1177/2472555217691719] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Lysophosphatidic acid (LPA) activates the G-protein-coupled receptor LPA1, which regulates various cellular processes, including cell proliferation and migration. Although LPA1 transduces cellular responses via Gq, Gi, and G12/13, associations between these signaling molecules and cellular phenotypes remain poorly characterized due to the lack of signal-specific pharmacological tools. Here, we characterized novel signal-biased modulators using multiple assays, including label-free impedance assays. LPA caused dramatic changes in cellular impedance in LPA1-expressing recombinant cells, which were susceptible to G-protein and protein kinase inhibitors. Subsequently, Gq-biased LPA1 negative allosteric modulators (NAMs) were identified using high-throughput screening, and a nonbiased antagonist differently affected the LPA-induced cellular impedance. These NAMs provide pharmacological tools for further investigations of the biology of LPA1.
Collapse
Affiliation(s)
- Yuji Shimizu
- 1 Biomolecular Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Japan
| | - Masaharu Nakayama
- 1 Biomolecular Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Japan
| |
Collapse
|
59
|
Yang Z, Yang F, Zhang D, Liu Z, Lin A, Liu C, Xiao P, Yu X, Sun JP. Phosphorylation of G Protein-Coupled Receptors: From the Barcode Hypothesis to the Flute Model. Mol Pharmacol 2017; 92:201-210. [DOI: 10.1124/mol.116.107839] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Accepted: 02/23/2017] [Indexed: 12/21/2022] Open
|
60
|
Abstract
This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.
Collapse
Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
| |
Collapse
|
61
|
Withey SL, Hill R, Lyndon A, Dewey WL, Kelly E, Henderson G. Effect of Tamoxifen and Brain-Penetrant Protein Kinase C and c-Jun N-Terminal Kinase Inhibitors on Tolerance to Opioid-Induced Respiratory Depression in Mice. J Pharmacol Exp Ther 2017; 361:51-59. [PMID: 28130265 DOI: 10.1124/jpet.116.238329] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/25/2017] [Indexed: 01/20/2023] Open
Abstract
Respiratory depression is the major cause of death in opioid overdose. We have previously shown that prolonged treatment of mice with morphine induces profound tolerance to the respiratory-depressant effects of the drug (Hill et al., 2016). The aim of the present study was to investigate whether tolerance to opioid-induced respiratory depression is mediated by protein kinase C (PKC) and/or c-Jun N-terminal kinase (JNK). We found that although mice treated for up to 6 days with morphine developed tolerance, as measured by the reduced responsiveness to an acute challenge dose of morphine, administration of the brain-penetrant PKC inhibitors tamoxifen and calphostin C restored the ability of acute morphine to produce respiratory depression in morphine-treated mice. Importantly, reversal of opioid tolerance was dependent on the nature of the opioid ligand used to induce tolerance, as these PKC inhibitors did not reverse tolerance induced by prolonged treatment of mice with methadone nor did they reverse the protection to acute morphine-induced respiratory depression afforded by prolonged treatment with buprenorphine. We found no evidence for the involvement of JNK in morphine-induced tolerance to respiratory depression. These results indicate that PKC represents a major mechanism underlying morphine tolerance, that the mechanism of opioid tolerance to respiratory depression is ligand-dependent, and that coadministration of drugs with PKC-inhibitory activity and morphine (as well as heroin, largely metabolized to morphine in the body) may render individuals more susceptible to overdose death by reversing tolerance to the effects of morphine.
Collapse
Affiliation(s)
- Sarah L Withey
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom (S.L.W., R.H., A.L., E.K., G.H.); and Virginia Commonwealth University, Richmond, Virginia (W.L.D.)
| | - Rob Hill
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom (S.L.W., R.H., A.L., E.K., G.H.); and Virginia Commonwealth University, Richmond, Virginia (W.L.D.)
| | - Abigail Lyndon
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom (S.L.W., R.H., A.L., E.K., G.H.); and Virginia Commonwealth University, Richmond, Virginia (W.L.D.)
| | - William L Dewey
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom (S.L.W., R.H., A.L., E.K., G.H.); and Virginia Commonwealth University, Richmond, Virginia (W.L.D.)
| | - Eamonn Kelly
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom (S.L.W., R.H., A.L., E.K., G.H.); and Virginia Commonwealth University, Richmond, Virginia (W.L.D.)
| | - Graeme Henderson
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom (S.L.W., R.H., A.L., E.K., G.H.); and Virginia Commonwealth University, Richmond, Virginia (W.L.D.)
| |
Collapse
|
62
|
Jung SR, Seo JB, Deng Y, Asbury CL, Hille B, Koh DS. Contributions of protein kinases and β-arrestin to termination of protease-activated receptor 2 signaling. ACTA ACUST UNITED AC 2016; 147:255-71. [PMID: 26927499 PMCID: PMC4772372 DOI: 10.1085/jgp.201511477] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Systematic imaging studies and modeling reveal new details of the regulation of the Gq-coupled GPCR, protease-activated receptor 2, by phosphorylation and β-arrestin. Activated Gq protein–coupled receptors (GqPCRs) can be desensitized by phosphorylation and β-arrestin binding. The kinetics and individual contributions of these two mechanisms to receptor desensitization have not been fully distinguished. Here, we describe the shut off of protease-activated receptor 2 (PAR2). PAR2 activates Gq and phospholipase C (PLC) to hydrolyze phosphatidylinositol 4,5-bisphosphate (PIP2) into diacylglycerol and inositol trisphosphate (IP3). We used fluorescent protein–tagged optical probes to monitor several consequences of PAR2 signaling, including PIP2 depletion and β-arrestin translocation in real time. During continuous activation of PAR2, PIP2 was depleted transiently and then restored within a few minutes, indicating fast receptor activation followed by desensitization. Knockdown of β-arrestin 1 and 2 using siRNA diminished the desensitization, slowing PIP2 restoration significantly and even adding a delayed secondary phase of further PIP2 depletion. These effects of β-arrestin knockdown on PIP2 recovery were prevented when serine/threonine phosphatases that dephosphorylate GPCRs were inhibited. Thus, PAR2 may continuously regain its activity via dephosphorylation when there is insufficient β-arrestin to trap phosphorylated receptors. Similarly, blockers of protein kinase C (PKC) and G protein–coupled receptor kinase potentiated the PIP2 depletion. In contrast, an activator of PKC inhibited receptor activation, presumably by augmenting phosphorylation of PAR2. Our interpretations were strengthened by modeling. Simulations supported the conclusions that phosphorylation of PAR2 by protein kinases initiates receptor desensitization and that recruited β-arrestin traps the phosphorylated state of the receptor, protecting it from phosphatases. Speculative thinking suggested a sequestration of phosphatidylinositol 4-phosphate 5 kinase (PIP5K) to the plasma membrane by β-arrestin to explain why knockdown of β-arrestin led to secondary depletion of PIP2. Indeed, artificial recruitment of PIP5K removed the secondary loss of PIP2 completely. Altogether, our experimental and theoretical approaches demonstrate roles and dynamics of the protein kinases, β-arrestin, and PIP5K in the desensitization of PAR2.
Collapse
Affiliation(s)
- Seung-Ryoung Jung
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Jong Bae Seo
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Yi Deng
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Charles L Asbury
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Bertil Hille
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Duk-Su Koh
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195 Department of Physics, Pohang University of Science and Technology, Pohang, Kyungbuk, 790-784, Republic of Korea
| |
Collapse
|
63
|
Distinct cortical and striatal actions of a β-arrestin-biased dopamine D2 receptor ligand reveal unique antipsychotic-like properties. Proc Natl Acad Sci U S A 2016; 113:E8178-E8186. [PMID: 27911814 DOI: 10.1073/pnas.1614347113] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The current dopamine (DA) hypothesis of schizophrenia postulates striatal hyperdopaminergia and cortical hypodopaminergia. Although partial agonists at DA D2 receptors (D2Rs), like aripiprazole, were developed to simultaneously target both phenomena, they do not effectively improve cortical dysfunction. In this study, we investigate the potential for newly developed β-arrestin2 (βarr2)-biased D2R partial agonists to simultaneously target hyper- and hypodopaminergia. Using neuron-specific βarr2-KO mice, we show that the antipsychotic-like effects of a βarr2-biased D2R ligand are driven through both striatal antagonism and cortical agonism of D2R-βarr2 signaling. Furthermore, βarr2-biased D2R agonism enhances firing of cortical fast-spiking interneurons. This enhanced cortical agonism of the biased ligand can be attributed to a lack of G-protein signaling and elevated expression of βarr2 and G protein-coupled receptor (GPCR) kinase 2 in the cortex versus the striatum. Therefore, we propose that βarr2-biased D2R ligands that exert region-selective actions could provide a path to develop more effective antipsychotic therapies.
Collapse
|
64
|
Guccione M, Ettari R, Taliani S, Da Settimo F, Zappalà M, Grasso S. G-Protein-Coupled Receptor Kinase 2 (GRK2) Inhibitors: Current Trends and Future Perspectives. J Med Chem 2016; 59:9277-9294. [PMID: 27362616 DOI: 10.1021/acs.jmedchem.5b01939] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
G-protein-coupled receptor kinase 2 (GRK2) is a G-protein-coupled receptor kinase that is ubiquitously expressed in many tissues and regulates various intracellular mechanisms. The up- or down-regulation of GRK2 correlates with several pathological disorders. GRK2 plays an important role in the maintenance of heart structure and function; thus, this kinase is involved in many cardiovascular diseases. GRK2 up-regulation can worsen cardiac ischemia; furthermore, increased kinase levels occur during the early stages of heart failure and in hypertensive subjects. GRK2 up-regulation can lead to changes in the insulin signaling cascade, which can translate to insulin resistance. Increased GRK2 levels also correlate with the degree of cognitive impairment that is typically observed in Alzheimer's disease. This article reviews the most potent and selective GRK2 inhibitors that have been developed. We focus on their mechanism of action, inhibition profile, and structure-activity relationships to provide insight into the further development of GRK2 inhibitors as drug candidates.
Collapse
Affiliation(s)
- Manuela Guccione
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina , Viale Annunziata, 98168 Messina, Italy
| | - Roberta Ettari
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina , Viale Annunziata, 98168 Messina, Italy
| | - Sabrina Taliani
- Dipartimento di Farmacia, Università di Pisa , Via Bonanno Pisano 6, 56126 Pisa, Italy
| | - Federico Da Settimo
- Dipartimento di Farmacia, Università di Pisa , Via Bonanno Pisano 6, 56126 Pisa, Italy
| | - Maria Zappalà
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina , Viale Annunziata, 98168 Messina, Italy
| | - Silvana Grasso
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina , Viale Annunziata, 98168 Messina, Italy
| |
Collapse
|
65
|
Penela P. Chapter Three - Ubiquitination and Protein Turnover of G-Protein-Coupled Receptor Kinases in GPCR Signaling and Cellular Regulation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 141:85-140. [PMID: 27378756 DOI: 10.1016/bs.pmbts.2016.04.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
G-protein-coupled receptors (GPCRs) are responsible for regulating a wide variety of physiological processes, and distinct mechanisms for GPCR inactivation exist to guarantee correct receptor functionality. One of the widely used mechanisms is receptor phosphorylation by specific G-protein-coupled receptor kinases (GRKs), leading to uncoupling from G proteins (desensitization) and receptor internalization. GRKs and β-arrestins also participate in the assembly of receptor-associated multimolecular complexes, thus initiating alternative G-protein-independent signaling events. In addition, the abundant GRK2 kinase has diverse "effector" functions in cellular migration, proliferation, and metabolism homeostasis by means of the phosphorylation or interaction with non-GPCR partners. Altered expression of GRKs (particularly of GRK2 and GRK5) occurs during pathological conditions characterized by impaired GPCR signaling including inflammatory syndromes, cardiovascular disease, and tumor contexts. It is increasingly appreciated that different pathways governing GRK protein stability play a role in the modulation of kinase levels in normal and pathological conditions. Thus, enhanced GRK2 degradation by the proteasome pathway occurs upon GPCR stimulation, what allows cellular adaptation to chronic stimulation in a physiological setting. β-arrestins participate in this process by facilitating GRK2 phosphorylation by different kinases and by recruiting diverse E3 ubiquitin ligase to the receptor complex. Different proteolytic systems (ubiquitin-proteasome, calpains), chaperone activities and signaling pathways influence the stability of GRKs in different ways, thus endowing specificity to GPCR regulation as protein turnover of GRKs can be differentially affected. Therefore, modulation of protein stability of GRKs emerges as a versatile mechanism for feedback regulation of GPCR signaling and basic cellular processes.
Collapse
Affiliation(s)
- P Penela
- Department of Molecular Biology and Centre of Molecular Biology "Severo Ochoa" (CSIC-UAM), Madrid, Autonomous University of Madrid, Madrid, Spain; Spain Health Research Institute The Princesa, Madrid, Spain.
| |
Collapse
|
66
|
|
67
|
“Barcode” and Differential Effects of GPCR Phosphorylation by Different GRKs. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2016. [DOI: 10.1007/978-1-4939-3798-1_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
68
|
Abstract
G protein-coupled receptors (GPCRs) remain a major domain of pharmaceutical discovery. The identification of GPCR lead compounds and their optimization are now structure-based, thanks to advances in X-ray crystallography, molecular modeling, protein engineering and biophysical techniques. In silico screening provides useful hit molecules. New pharmacological approaches to tuning the pleotropic action of GPCRs include: allosteric modulators, biased ligands, GPCR heterodimer-targeted compounds, manipulation of polypharmacology, receptor antibodies and tailoring of drug molecules to fit GPCR pharmacogenomics. Measurements of kinetics and drug efficacy are factors influencing clinical success. With the exception of inhibitors of GPCR kinases, targeting of intracellular GPCR signaling or receptor cycling for therapeutic purposes remains a futuristic concept. New assay approaches are more efficient and multidimensional: cell-based, label-free, fluorescence-based assays, and biosensors. Tailoring GPCR drugs to a patient's genetic background is now being considered. Chemoinformatic tools can predict ADME-tox properties. New imaging technology visualizes drug action in vivo. Thus, there is reason to be optimistic that new technology for GPCR ligand discovery will help reverse the current narrowing of the pharmaceutical pipeline.
Collapse
Affiliation(s)
- Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bldg. 8A, Rm. B1A-19, Bethesda, Maryland 20892, USA.
| |
Collapse
|