1
|
Shen S, Wu C, Lin G, Yang X, Zhou Y, Zhao C, Miao Z, Tian X, Wang K, Yang Z, Liu Z, Guo N, Li Y, Xia A, Zhou P, Liu J, Yan W, Ke B, Yang S, Shao Z. Structure-based identification of a G protein-biased allosteric modulator of cannabinoid receptor CB1. Proc Natl Acad Sci U S A 2024; 121:e2321532121. [PMID: 38830102 DOI: 10.1073/pnas.2321532121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 04/01/2024] [Indexed: 06/05/2024] Open
Abstract
Cannabis sativa is known for its therapeutic benefit in various diseases including pain relief by targeting cannabinoid receptors. The primary component of cannabis, Δ9-tetrahydrocannabinol (THC), and other agonists engage the orthosteric site of CB1, activating both Gi and β-arrestin signaling pathways. The activation of diverse pathways could result in on-target side effects and cannabis addiction, which may hinder therapeutic potential. A significant challenge in pharmacology is the design of a ligand that can modulate specific signaling of CB1. By leveraging insights from the structure-function selectivity relationship (SFSR), we have identified Gi signaling-biased agonist-allosteric modulators (ago-BAMs). Further, two cryoelectron microscopy (cryo-EM) structures reveal the binding mode of ago-BAM at the extrahelical allosteric site of CB1. Combining mutagenesis and pharmacological studies, we elucidated the detailed mechanism of ago-BAM-mediated biased signaling. Notably, ago-BAM CB-05 demonstrated analgesic efficacy with fewer side effects, minimal drug toxicity and no cannabis addiction in mouse pain models. In summary, our finding not only suggests that ago-BAMs of CB1 provide a potential nonopioid strategy for pain management but also sheds light on BAM identification for GPCRs.
Collapse
Affiliation(s)
- Siyuan Shen
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
- Frontiers Medical Center, Tianfu Jincheng Laboratory, Chengdu 610212, Sichuan, China
| | - Chao Wu
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Guifeng Lin
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Xin Yang
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Yangli Zhou
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Chang Zhao
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Zhuang Miao
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Xiaowen Tian
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Kexin Wang
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Zhiqian Yang
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Zhiyu Liu
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Nihong Guo
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Yueshan Li
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Anjie Xia
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Pei Zhou
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Jingming Liu
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Wei Yan
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Bowen Ke
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Shengyong Yang
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
- Frontiers Medical Center, Tianfu Jincheng Laboratory, Chengdu 610212, Sichuan, China
| | - Zhenhua Shao
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
- Frontiers Medical Center, Tianfu Jincheng Laboratory, Chengdu 610212, Sichuan, China
| |
Collapse
|
2
|
Bernhard SM, Han J, Che T. GPCR-G protein selectivity revealed by structural pharmacology. FEBS J 2023. [PMID: 38151714 DOI: 10.1111/febs.17049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/28/2023] [Accepted: 12/27/2023] [Indexed: 12/29/2023]
Abstract
Receptor-G protein promiscuity is frequently observed in class A G protein-coupled receptors (GPCRs). In particular, GPCRs can couple with G proteins from different families (Gαs, Gαq/11, Gαi/o, and Gα12/13) or the same family subtypes. The molecular basis underlying the selectivity/promiscuity is not fully revealed. We recently reported the structures of kappa opioid receptor (KOR) in complex with the Gi/o family subtypes [Gαi1, GαoA, Gαz, and Gustducin (Gαg)] determined by cryo-electron microscopy (cryo-EM). The structural analysis, in combination with pharmacological studies, provides insights into Gi/o subtype selectivity. Given the conserved sequence identity and activation mechanism between different G protein families, the findings within Gi/o subtypes could be likely extended to other families. Understanding the KOR-Gi/o or GPCR-G protein selectivity will facilitate the development of more precise therapeutics targeting a specific G protein subtype.
Collapse
Affiliation(s)
- Sarah M Bernhard
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, St. Louis, MO, USA
| | - Jianming Han
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, St. Louis, MO, USA
| | - Tao Che
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, St. Louis, MO, USA
| |
Collapse
|
3
|
Ramos-Gonzalez N, Paul B, Majumdar S. IUPHAR themed review: Opioid efficacy, bias, and selectivity. Pharmacol Res 2023; 197:106961. [PMID: 37844653 DOI: 10.1016/j.phrs.2023.106961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/18/2023]
Abstract
Drugs acting at the opioid receptor family are clinically used to treat chronic and acute pain, though they represent the second line of treatment behind GABA analogs, antidepressants and SSRI's. Within the opioid family mu and kappa opioid receptor are commonly targeted. However, activation of the mu opioid receptor has side effects of constipation, tolerance, dependence, euphoria, and respiratory depression; activation of the kappa opioid receptor leads to dysphoria and sedation. The side effects of mu opioid receptor activation have led to mu receptor drugs being widely abused with great overdose risk. For these reasons, newer safer opioid analgesics are in high demand. For many years a focus within the opioid field was finding drugs that activated the G protein pathway at mu opioid receptor, without activating the β-arrestin pathway, known as biased agonism. Recent advances have shown that this may not be the way forward to develop safer analgesics at mu opioid receptor, though there is still some promise at the kappa opioid receptor. Here we discuss recent novel approaches to develop safer opioid drugs including efficacy vs bias and fine-tuning receptor activation by targeting sub-pockets in the orthosteric site, we explore recent works on the structural basis of bias, and we put forward the suggestion that Gα subtype selectivity may be an exciting new area of interest.
Collapse
Affiliation(s)
- Nokomis Ramos-Gonzalez
- Department of Anesthesiology and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St. Louis and Washington University School of Medicine, St. Louis, MO, USA
| | - Barnali Paul
- Department of Anesthesiology and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St. Louis and Washington University School of Medicine, St. Louis, MO, USA
| | - Susruta Majumdar
- Department of Anesthesiology and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St. Louis and Washington University School of Medicine, St. Louis, MO, USA.
| |
Collapse
|
4
|
Chan YJ, Hsiao G, Wan WN, Yang TM, Tsai CH, Kang JJ, Lee YC, Fang TC, Cheng YW, Li CH. Blue light exposure collapses the inner blood-retinal barrier by accelerating endothelial CLDN5 degradation through the disturbance of GNAZ and the activation of ADAM17. Fluids Barriers CNS 2023; 20:31. [PMID: 37095509 PMCID: PMC10124034 DOI: 10.1186/s12987-023-00430-7] [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: 12/08/2022] [Accepted: 04/07/2023] [Indexed: 04/26/2023] Open
Abstract
Blue light is part of the natural light spectrum that emits high energy. Currently, people are frequently exposed to blue light from 3C devices, resulting in a growing incidence of retinopathy. The retinal vasculature is complex, and retinal vessels not only serve the metabolic needs of the retinal sublayers, but also maintain electrolyte homeostasis by forming the inner blood-retinal barrier (iBRB). The iBRB, which is primarily composed of endothelial cells, has well-developed tight junctions. However, with exposure to blue light, the risks of targeting retinal endothelial cells are currently unknown. We found that endothelial claudin-5 (CLDN5) was rapidly degraded under blue light, coinciding with the activation of a disintegrin and metalloprotease 17 (ADAM17), even at non-cytotoxic lighting. An apparently broken tight junction and a permeable paracellular cleft were observed. Mice exposed to blue light displayed iBRB leakage, conferring attenuation of the electroretinogram b-wave and oscillatory potentials. Both pharmacological and genetic inhibition of ADAM17 remarkably alleviated CLDN5 degradation induced by blue light. Under untreated condition, ADAM17 is sequestered by GNAZ (a circadian-responsive, retina-enriched inhibitory G protein), whereas ADAM17 escapes from GNAZ by blue light illuminance. GNAZ knockdown led to ADAM17 hyperactivation, CLDN5 downregulation, and paracellular permeability in vitro, and retinal damage mimicked blue light exposure in vivo. These data demonstrate that blue light exposure might impair the iBRB by accelerating CLDN5 degradation through the disturbance of the GNAZ-ADAM17 axis.
Collapse
Affiliation(s)
- Yen-Ju Chan
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan
- School of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan
| | - George Hsiao
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
- TMU Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan
| | - Wang-Nok Wan
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan
| | - Tsung-Min Yang
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan
- School of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan
| | - Chi-Hao Tsai
- Department of Ophthalmology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jaw-Jou Kang
- Institute of Food Safety and Health Risk Assessment, School of Pharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan
| | - Yu-Cheng Lee
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Te-Chao Fang
- TMU Research Center of Urology and Kidney, Taipei Medical University, Taipei, Taiwan
- Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yu-Wen Cheng
- School of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan.
- TMU Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan.
| | - Ching-Hao Li
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei, 110, Taiwan.
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.
- TMU Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan.
| |
Collapse
|
5
|
Sakloth F, Sanchez-Reyes OB, Ruiz A, Nicolais A, Serafini RA, Pryce KD, Bertherat F, Torres-Berrío A, Gomes I, Devi LA, Wacker D, Zachariou V. A Regional and Projection-Specific Role of RGSz1 in the Ventrolateral Periaqueductal Grey in the Modulation of Morphine Reward. Mol Pharmacol 2023; 103:1-8. [PMID: 36310031 PMCID: PMC11033942 DOI: 10.1124/molpharm.122.000528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 09/12/2022] [Accepted: 10/11/2022] [Indexed: 02/03/2023] Open
Abstract
Opioid analgesics exert their therapeutic and adverse effects by activating μ opioid receptors (MOPR); however, functional responses to MOPR activation are modulated by distinct signal transduction complexes within the brain. The ventrolateral periaqueductal gray (vlPAG) plays a critical role in modulation of nociception and analgesia, but the exact intracellular pathways associated with opioid responses in this region are not fully understood. We previously showed that knockout of the signal transduction modulator Regulator of G protein Signaling z1 (RGSz1) enhanced analgesic responses to opioids, whereas it decreased the rewarding efficacy of morphine. Here, we applied viral mediated gene transfer methodology and delivered adeno-associated virus (AAV) expressing Cre recombinase to the vlPAG of RGSz1fl\fl mice to demonstrate that downregulation of RGSz1 in this region decreases sensitivity to morphine in the place preference paradigm, under pain-free as well as neuropathic pain states. We also used retrograde viral vectors along with flippase-dependent Cre vectors to conditionally downregulate RGSz1 in vlPAG projections to the ventral tegmental area (VTA) and show that downregulation of RGSz1 prevents the development of place conditioning to low morphine doses. Consistent with the role for RGSz1 as a negative modulator of MOPR activity, RGSz1KO enhances opioid-induced cAMP inhibition in periaqueductal gray (PAG) membranes. Furthermore, using a new generation of bioluminescence resonance energy transfer (BRET) sensors, we demonstrate that RGSz1 modulates Gαz but not other Gαi family subunits and selectively impedes MOPR-mediated Gαz signaling events invoked by morphine and other opioids. Our work highlights a regional and circuit-specific role of the G protein-signaling modulator RGSz1 in morphine reward, providing insights on midbrain intracellular pathways that control addiction-related behaviors. SIGNIFICANCE STATEMENT: This study used advanced genetic mouse models to highlight the role of the signal transduction modulator named RGSz1 in responses to clinically used opioid analgesics. We show that RGSz1 controls the rewarding efficacy of opioids by actions in ventrolateral periaqueductal gray projections to the ventral tegmental area, a key component of the midbrain dopamine pathway. These studies highlight novel mechanisms by which pain-modulating structures control the rewarding efficacy of opioids.
Collapse
Affiliation(s)
- Farhana Sakloth
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Omar B Sanchez-Reyes
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Anne Ruiz
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Andrew Nicolais
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Randal A Serafini
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Kerri D Pryce
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Feodora Bertherat
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Angélica Torres-Berrío
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Ivone Gomes
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Lakshmi A Devi
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Daniel Wacker
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| | - Venetia Zachariou
- Nash Family Department of Neuroscience, Friedman Brain Institute (F.S., A.R., A.N., R.A.S., K.D.P., F.B., A.T.-B., L.A.D., D.W., V.Z.) and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (O.B.S.R., I.G., L.A.D., D.W., V.Z.)
| |
Collapse
|
6
|
Faouzi A, Wang H, Zaidi SA, DiBerto JF, Che T, Qu Q, Robertson MJ, Madasu MK, El Daibani A, Varga BR, Zhang T, Ruiz C, Liu S, Xu J, Appourchaux K, Slocum ST, Eans SO, Cameron MD, Al-Hasani R, Pan YX, Roth BL, McLaughlin JP, Skiniotis G, Katritch V, Kobilka BK, Majumdar S. Structure-based design of bitopic ligands for the µ-opioid receptor. Nature 2023; 613:767-774. [PMID: 36450356 PMCID: PMC10328120 DOI: 10.1038/s41586-022-05588-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 11/22/2022] [Indexed: 12/05/2022]
Abstract
Mu-opioid receptor (µOR) agonists such as fentanyl have long been used for pain management, but are considered a major public health concern owing to their adverse side effects, including lethal overdose1. Here, in an effort to design safer therapeutic agents, we report an approach targeting a conserved sodium ion-binding site2 found in µOR3 and many other class A G-protein-coupled receptors with bitopic fentanyl derivatives that are functionalized via a linker with a positively charged guanidino group. Cryo-electron microscopy structures of the most potent bitopic ligands in complex with µOR highlight the key interactions between the guanidine of the ligands and the key Asp2.50 residue in the Na+ site. Two bitopics (C5 and C6 guano) maintain nanomolar potency and high efficacy at Gi subtypes and show strongly reduced arrestin recruitment-one (C6 guano) also shows the lowest Gz efficacy among the panel of µOR agonists, including partial and biased morphinan and fentanyl analogues. In mice, C6 guano displayed µOR-dependent antinociception with attenuated adverse effects, supporting the µOR sodium ion-binding site as a potential target for the design of safer analgesics. In general, our study suggests that bitopic ligands that engage the sodium ion-binding pocket in class A G-protein-coupled receptors can be designed to control their efficacy and functional selectivity profiles for Gi, Go and Gz subtypes and arrestins, thus modulating their in vivo pharmacology.
Collapse
MESH Headings
- Animals
- Mice
- Analgesics, Opioid/chemistry
- Analgesics, Opioid/metabolism
- Arrestins/metabolism
- Cryoelectron Microscopy
- Fentanyl/analogs & derivatives
- Fentanyl/chemistry
- Fentanyl/metabolism
- Ligands
- Morphinans/chemistry
- Morphinans/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/chemistry
- Receptors, Opioid, mu/metabolism
- Receptors, Opioid, mu/ultrastructure
- Binding Sites
- Nociception
- Drug Design
Collapse
Affiliation(s)
- Abdelfattah Faouzi
- Center for Clinical Pharmacology, University of Health Sciences and Pharmacy and Washington University School of Medicine, St Louis, MO, USA
| | - Haoqing Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Saheem A Zaidi
- Department of Quantitative and Computational Biology, Department of Chemistry, Bridge Institute and Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA, USA
| | - Jeffrey F DiBerto
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Tao Che
- Center for Clinical Pharmacology, University of Health Sciences and Pharmacy and Washington University School of Medicine, St Louis, MO, USA
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Qianhui Qu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Michael J Robertson
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Manish K Madasu
- Center for Clinical Pharmacology, University of Health Sciences and Pharmacy and Washington University School of Medicine, St Louis, MO, USA
| | - Amal El Daibani
- Center for Clinical Pharmacology, University of Health Sciences and Pharmacy and Washington University School of Medicine, St Louis, MO, USA
| | - Balazs R Varga
- Center for Clinical Pharmacology, University of Health Sciences and Pharmacy and Washington University School of Medicine, St Louis, MO, USA
| | - Tiffany Zhang
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Claudia Ruiz
- Department of Chemistry, Scripps Research, Jupiter, FL, USA
| | - Shan Liu
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Jin Xu
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Kevin Appourchaux
- Center for Clinical Pharmacology, University of Health Sciences and Pharmacy and Washington University School of Medicine, St Louis, MO, USA
| | - Samuel T Slocum
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Shainnel O Eans
- Department of Pharmacodynamics, University of Florida, Gainesville, FL, USA
| | | | - Ream Al-Hasani
- Center for Clinical Pharmacology, University of Health Sciences and Pharmacy and Washington University School of Medicine, St Louis, MO, USA
| | - Ying Xian Pan
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Jay P McLaughlin
- Department of Pharmacodynamics, University of Florida, Gainesville, FL, USA
| | - Georgios Skiniotis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.
| | - Vsevolod Katritch
- Department of Quantitative and Computational Biology, Department of Chemistry, Bridge Institute and Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA, USA.
| | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.
| | - Susruta Majumdar
- Center for Clinical Pharmacology, University of Health Sciences and Pharmacy and Washington University School of Medicine, St Louis, MO, USA.
| |
Collapse
|
7
|
Paul B, Sribhashyam S, Majumdar S. Opioid signaling and design of analgesics. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 195:153-176. [PMID: 36707153 PMCID: PMC10325139 DOI: 10.1016/bs.pmbts.2022.06.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Clinical treatment of acute to severe pain relies on the use of opioids. While their potency is significant, there are considerable side effects that can negatively affect patients. Their rise in usage has correlated with the current opioid epidemic in the United States, which has led to more than 70,000 deaths per year (Volkow and Blanco, 2021). Opioid-related drug development aims to make target compounds that show strong potency but with diminished side effects. Research into pharmaceuticals that could act as potential alternatives to current pains medications has relied on mechanistic insights of opioid receptors, a class of G-protein coupled receptors (GPCRs), and biased agonism, a common phenomenon among pharmaceutical compounds where downstream effects can be altered at the same receptor via different agonists. Opioids function typically by binding to an active site on the extracellular portion of opioid receptors. Once activated, the opioid receptor initiates a G-protein signaling pathway and/or the β-arrestin2 pathway. The proposed concept for the development of safe analgesics around mu and kappa opioid receptor subtypes has focused on not recruiting β-arrestin2 (biased agonism) and/or having low efficacy at the receptor (partial agonism). By altering chemical motifs on a common scaffold, chemists can take advantage of biased agonism as well as create compounds with low intrinsic efficacy for the desired treatments. This review will focus on ligands with bias profile, signaling aspects of the receptor and probe into the structural basis of receptor that leads to bias and/or partial agonism.
Collapse
Affiliation(s)
- Barnali Paul
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St Louis and Washington University School of Medicine, St Louis, MO, United States
| | - Sashrik Sribhashyam
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St Louis and Washington University School of Medicine, St Louis, MO, United States
| | - Susruta Majumdar
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St Louis and Washington University School of Medicine, St Louis, MO, United States.
| |
Collapse
|
8
|
GRK2 regulates ADP signaling in platelets via P2Y1 and P2Y12. Blood Adv 2022; 6:4524-4536. [PMID: 35793439 DOI: 10.1182/bloodadvances.2022007007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 06/10/2022] [Indexed: 11/20/2022] Open
Abstract
The critical role of GRK2 in regulating cardiac function has been well documented for over three decades. Therefore, targeting GRK2 has been extensively studied as a novel approach to treat cardiovascular disease. However, little is known about its role in hemostasis and thrombosis. Here we provide the first evidence that GRK2 limits platelet activation and regulates the hemostatic response to injury. Deletion of GRK2 in mouse platelets causes increased platelet accumulation following laser-induced injury in cremaster muscle arterioles, shortens tail bleeding time, and enhances thrombosis in ADP-induced pulmonary thromboembolism and in FeCl3-induced carotid injury. GRK2-/- platelets have increased integrin activation, P-selectin exposure, and platelet aggregation in response to ADP stimulation. Furthermore, GRK2-/- platelets retain the ability to aggregate in response to ADP re-stimulation, indicating that GRK2 contributes to ADP receptor desensitization. Underlying these changes in GRK2-/- platelets is an increase in Ca2+ mobilization, RAP1 activation, and Akt phosphorylation stimulated by ADP, and an attenuated rise of cAMP levels in response to ADP in the presence of prostaglandin I2. P2Y12 antagonist treatment eliminates the phenotypic difference in platelet accumulation between WT and GRK2-/- mice at the site of injury. Pharmacologic inhibition of GRK2 activity in human platelets increases platelet activation in response to ADP. Finally, we show that GRK2 binds to endogenous Gβγ subunits during platelet activation. Collectively, these results show that GRK2 regulates ADP signaling via P2Y1 and P2Y12, interacts with Gβγ, and functions as a signaling hub in platelets for modulating the hemostatic response to injury.
Collapse
|
9
|
Hanson J. [G proteins: privileged transducers of 7-transmembrane spanning receptors]. Biol Aujourdhui 2022; 215:95-106. [PMID: 35275054 DOI: 10.1051/jbio/2021011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Indexed: 06/14/2023]
Abstract
G protein-coupled receptors or GPCR are the most abundant membrane receptors in our genome with around 800 members. They play an essential role in most physiological and pathophysiological phenomena. In addition, they constitute 30% of the targets of currently marketed drugs and remain an important reservoir for new innovative therapies. Their main effectors are heterotrimeric G proteins. These are composed of 3 subunits, α, β and γ, which, upon coupling with a GPCR, dissociate into Gα and Gβγ to activate numerous signaling pathways. This article describes some of the recent advances in understanding the function and role of heterotrimeric G proteins. After a short introduction to GPCRs, the history of the discovery of G proteins is briefly described. Then, the fundamental mechanisms of activation, signaling and regulation of G proteins are reviewed. New paradigms concerning intracellular signaling, specific recognition of G proteins by GPCRs as well as biased signaling are also discussed.
Collapse
Affiliation(s)
- Julien Hanson
- Laboratoire de Pharmacologie Moléculaire, GIGA-Molecular Biology of Diseases, Université de Liège, CHU, B34, Tour GIGA (+4), Avenue de l'Hôpital 11, B-4000 Liège, Belgique
| |
Collapse
|
10
|
G protein-coupled receptor kinase 5 regulates thrombin signaling in platelets via PAR-1. Blood Adv 2021; 6:2319-2330. [PMID: 34581777 PMCID: PMC9006276 DOI: 10.1182/bloodadvances.2021005453] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/12/2021] [Indexed: 11/22/2022] Open
Abstract
Platelet reactivity via the PAR-1 thrombin receptor is mediated by GRK5. Platelet GRK5 is associated with thrombus formation in humans and mice.
The interindividual variation in the functional response of platelets to activation by agonists is heritable. Genome-wide association studies (GWASs) of quantitative measures of platelet function have identified fewer than 20 distinctly associated variants, some with unknown mechanisms. Here, we report GWASs of pathway-specific functional responses to agonism by adenosine 5′-diphosphate, a glycoprotein VI–specific collagen mimetic, and thrombin receptor-agonist peptides, each specific to 1 of the G protein–coupled receptors PAR-1 and PAR-4, in subsets of 1562 individuals. We identified an association (P = 2.75 × 10−40) between a common intronic variant, rs10886430, in the G protein–coupled receptor kinase 5 gene (GRK5) and the sensitivity of platelets to activate through PAR-1. The variant resides in a megakaryocyte-specific enhancer that is bound by the transcription factors GATA1 and MEIS1. The minor allele (G) is associated with fewer GRK5 transcripts in platelets and the greater sensitivity of platelets to activate through PAR-1. We show that thrombin-mediated activation of human platelets causes binding of GRK5 to PAR-1 and that deletion of the mouse homolog Grk5 enhances thrombin-induced platelet activation sensitivity and increases platelet accumulation at the site of vascular injury. This corroborates evidence that the human G allele of rs10886430 is associated with a greater risk for cardiovascular disease. In summary, by combining the results of pathway-specific GWASs and expression quantitative trait locus studies in humans with the results from platelet function studies in Grk5−/− mice, we obtain evidence that GRK5 regulates the human platelet response to thrombin via the PAR-1 pathway.
Collapse
|
11
|
Golaszewska A, Misztal T, Marcinczyk N, Chabielska E, Rusak T. Adrenaline May Contribute to Prothrombotic Condition via Augmentation of Platelet Procoagulant Response, Enhancement of Fibrin Formation, and Attenuation of Fibrinolysis. Front Physiol 2021; 12:657881. [PMID: 34025450 PMCID: PMC8134743 DOI: 10.3389/fphys.2021.657881] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 04/13/2021] [Indexed: 01/08/2023] Open
Abstract
Background: Adrenaline is believed to play a role in thrombosis and hemostasis. The complex effect of its clinically relevant concentrations on thrombus formation, coagulation and fibrinolysis in human blood has never been specifically studied. Methods: Confocal microscopy was used to study thrombus formation under flow, exposure of phosphatidylserine (PS) in adhered platelets, to evaluate clots density, and to measure kinetics of fibrin formation and external fibrinolysis under flow. Flow cytometry was utilized to assess PS exposure in non-adhered platelets. Kinetics of clot formation and internal fibrinolysis was evaluated by thromboelastometry. Platelet aggregation was measured by optical aggremometry. Kinetics of clot retraction was assessed by using digital camera. Results: We found that adrenaline (1-10 nM) is able to enhance platelet activation evoked by subthreshold collagen (150 ng/ml), resulting in augmentation of platelet aggregation, thrombus formation under arterial flow conditions, platelet PS exposure, and formation of platelet-fibrin clots. The development of platelet procoagulant response evoked by adrenaline + low collagen was associated with the formation of denser platelet-fibrin clots and the decrease in rate of fibrinolysis despite whether lysis was initiated inside (internal fibrinolysis) or outside the clot (external fibrinolysis). The above phenomena were abolished by the α2-adrenergic receptor antagonist, rauwolscine. Adrenaline-collagen synergism, expressed as PS exposure, was significantly reduced by cyclooxygenase inhibitor (acetylsalicic acid), GPIIb/IIIa receptor blocker (tirofiban), and P2Y12 receptor antagonist (PSB 0739). Conclusion: Clinically relevant concentrations of adrenaline may significantly augment responses of human platelets in the presence of subthreshold concentrations of collagen, which should be considered during therapies involving adrenaline infusion. Routinely used antiplatelet drugs may reduce the prothrombotic state evoked by adrenaline-collagen synergism.
Collapse
Affiliation(s)
- Agata Golaszewska
- Department of Physical Chemistry, Medical University of Bialystok, Bialystok, Poland
| | - Tomasz Misztal
- Department of Physical Chemistry, Medical University of Bialystok, Bialystok, Poland
| | - Natalia Marcinczyk
- Department of Biopharmacy, Medical University of Bialystok, Bialystok, Poland
| | - Ewa Chabielska
- Department of Biopharmacy, Medical University of Bialystok, Bialystok, Poland
| | - Tomasz Rusak
- Department of Physical Chemistry, Medical University of Bialystok, Bialystok, Poland
| |
Collapse
|
12
|
Angelis I, Moussis V, Tsoukatos DC, Tsikaris V. Multidrug Resistance Protein 4 (MRP4/ABCC4): A Suspected Efflux Transporter for Human's Platelet Activation. Protein Pept Lett 2021; 28:983-995. [PMID: 33964863 DOI: 10.2174/0929866528666210505120659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/10/2021] [Accepted: 03/16/2021] [Indexed: 11/22/2022]
Abstract
The main role of platelets is to contribute to hemostasis. However, under pathophysiological conditions, platelet activation may lead to thrombotic events of cardiovascular diseases. Thus, anti-thrombotic treatment is important in patients with cardiovascular disease. This review focuses on a platelet receptor, a transmembrane protein, the Multidrug Resistance Protein 4, MRP4, which contributes to platelet activation by extruding endogenous molecules responsible for their activation and accumulation. The regulation of the intracellular concentration levels of these molecules by MRP4 turned to make the protein suspicious and, at the same time, an interesting regulatory factor of normal platelet function. Especially, the possible role of MRP4 in the excretion of xenobiotic and antiplatelet drugs such as aspirin is discussed, thus imparting platelet aspirin tolerance and correlating the protein with the ineffectiveness of aspirin antiplatelet therapy. Based on the above, this review finally underlines that the development of a highly selective and targeted strategy for platelet MRP4 inhibition will also lead to inhibition of platelet activation and accumulation.
Collapse
Affiliation(s)
- Ioannis Angelis
- Department of Chemistry, Organic Chemistry & Biochemistry, University of Ioannina, Ioannina. Greece
| | - Vassilios Moussis
- Department of Chemistry, Organic Chemistry & Biochemistry, University of Ioannina, Ioannina. Greece
| | - Demokritos C Tsoukatos
- Department of Chemistry, Organic Chemistry & Biochemistry, University of Ioannina, Ioannina. Greece
| | - Vassilios Tsikaris
- Department of Chemistry, Organic Chemistry & Biochemistry, University of Ioannina, Ioannina. Greece
| |
Collapse
|
13
|
Che T, Dwivedi-Agnihotri H, Shukla AK, Roth BL. Biased ligands at opioid receptors: Current status and future directions. Sci Signal 2021; 14:14/677/eaav0320. [PMID: 33824179 DOI: 10.1126/scisignal.aav0320] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The opioid crisis represents a major worldwide public health crisis that has accelerated the search for safer and more effective opioids. Over the past few years, the identification of biased opioid ligands capable of eliciting selective functional responses has provided an alternative avenue to develop novel therapeutics without the side effects of current opioid medications. However, whether biased agonism or other pharmacological properties, such as partial agonism (or low efficacy), account for the therapeutic benefits remains questionable. Here, we provide a summary of the current status of biased opioid ligands that target the μ- and κ-opioid receptors and highlight advances in preclinical and clinical trials of some of these ligands. We also discuss an example of structure-based biased ligand discovery at the μ-opioid receptor, an approach that could revolutionize drug discovery at opioid and other receptors. Last, we briefly discuss caveats and future directions for this important area of research.
Collapse
Affiliation(s)
- Tao Che
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA.
| | - Hemlata Dwivedi-Agnihotri
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Arun K Shukla
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA. .,National Institute of Mental Health Psychoactive Drug Screening Program, School of Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA.,Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| |
Collapse
|
14
|
Braune S, Küpper JH, Jung F. Effect of Prostanoids on Human Platelet Function: An Overview. Int J Mol Sci 2020; 21:ijms21239020. [PMID: 33260972 PMCID: PMC7730041 DOI: 10.3390/ijms21239020] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 12/11/2022] Open
Abstract
Prostanoids are bioactive lipid mediators and take part in many physiological and pathophysiological processes in practically every organ, tissue and cell, including the vascular, renal, gastrointestinal and reproductive systems. In this review, we focus on their influence on platelets, which are key elements in thrombosis and hemostasis. The function of platelets is influenced by mediators in the blood and the vascular wall. Activated platelets aggregate and release bioactive substances, thereby activating further neighbored platelets, which finally can lead to the formation of thrombi. Prostanoids regulate the function of blood platelets by both activating or inhibiting and so are involved in hemostasis. Each prostanoid has a unique activity profile and, thus, a specific profile of action. This article reviews the effects of the following prostanoids: prostaglandin-D2 (PGD2), prostaglandin-E1, -E2 and E3 (PGE1, PGE2, PGE3), prostaglandin F2α (PGF2α), prostacyclin (PGI2) and thromboxane-A2 (TXA2) on platelet activation and aggregation via their respective receptors.
Collapse
|
15
|
DeHelian D, Gupta S, Wu J, Thorsheim C, Estevez B, Cooper M, Litts K, Lee-Sundlov MM, Hoffmeister KM, Poncz M, Ma P, Brass LF. RGS10 and RGS18 differentially limit platelet activation, promote platelet production, and prolong platelet survival. Blood 2020; 136:1773-1782. [PMID: 32542378 PMCID: PMC7544544 DOI: 10.1182/blood.2019003251] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 05/22/2020] [Indexed: 12/23/2022] Open
Abstract
G protein-coupled receptors are critical mediators of platelet activation whose signaling can be modulated by members of the regulator of G protein signaling (RGS) family. The 2 most abundant RGS proteins in human and mouse platelets are RGS10 and RGS18. While each has been studied individually, critical questions remain about the overall impact of this mode of regulation in platelets. Here, we report that mice missing both proteins show reduced platelet survival and a 40% decrease in platelet count that can be partially reversed with aspirin and a P2Y12 antagonist. Their platelets have increased basal (TREM)-like transcript-1 expression, a leftward shift in the dose/response for a thrombin receptor-activating peptide, an increased maximum response to adenosine 5'-diphosphate and TxA2, and a greatly exaggerated response to penetrating injuries in vivo. Neither of the individual knockouts displays this constellation of findings. RGS10-/- platelets have an enhanced response to agonists in vitro, but platelet count and survival are normal. RGS18-/- mice have a 15% reduction in platelet count that is not affected by antiplatelet agents, nearly normal responses to platelet agonists, and normal platelet survival. Megakaryocyte number and ploidy are normal in all 3 mouse lines, but platelet recovery from severe acute thrombocytopenia is slower in RGS18-/- and RGS10-/-18-/- mice. Collectively, these results show that RGS10 and RGS18 have complementary roles in platelets. Removing both at the same time discloses the extent to which this regulatory mechanism normally controls platelet reactivity in vivo, modulates the hemostatic response to injury, promotes platelet production, and prolongs platelet survival.
Collapse
Affiliation(s)
- Daniel DeHelian
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA
| | - Shuchi Gupta
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA
| | - Jie Wu
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA
| | - Chelsea Thorsheim
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA
| | - Brian Estevez
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia PA
| | - Matthew Cooper
- Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Kelly Litts
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA
| | - Melissa M Lee-Sundlov
- Department of Biochemistry and
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI
- Versiti Blood Research Institute, Milwaukee, WI; and
| | - Karin M Hoffmeister
- Department of Biochemistry and
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI
- Versiti Blood Research Institute, Milwaukee, WI; and
| | - Mortimer Poncz
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia PA
| | - Peisong Ma
- Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Lawrence F Brass
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, PA
| |
Collapse
|
16
|
Chaudhary PK, Kim S, Jee Y, Lee SH, Park KM, Kim S. Role of GRK6 in the Regulation of Platelet Activation through Selective G Protein-Coupled Receptor (GPCR) Desensitization. Int J Mol Sci 2020; 21:ijms21113932. [PMID: 32486261 PMCID: PMC7312169 DOI: 10.3390/ijms21113932] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/25/2020] [Accepted: 05/28/2020] [Indexed: 12/27/2022] Open
Abstract
Platelet G protein-coupled receptors (GPCRs) regulate platelet function by mediating the response to various agonists, including adenosine diphosphate (ADP), thromboxane A2, and thrombin. Although GPCR kinases (GRKs) are considered to have the crucial roles in most GPCR functions, little is known regarding the regulation of GPCR signaling and mechanisms of GPCR desensitization by GRKs in platelets. In this study, we investigated the functional role of GRK6 and the molecular basis for regulation of specific GPCR desensitization by GRK6 in platelets. We used GRK6 knockout mice to evaluate the functional role of GRK6 in platelet activation. Platelet aggregation, dense- and α-granule secretion, and fibrinogen receptor activation induced by 2-MeSADP, U46619, thrombin, and AYPGKF were significantly potentiated in GRK6−/− platelets compared to the wild-type (WT) platelets. However, collagen-related peptide (CRP)-induced platelet aggregation and secretion were not affected in GRK6−/− platelets. Interestingly, platelet aggregation induced by co-stimulation of serotonin and epinephrine which activate Gq-coupled 5HT2A and Gz-coupled α2A adrenergic receptors, respectively, was not affected in GRK6−/− platelets, suggesting that GRK6 was involved in specific GPCR regulation. In addition, platelet aggregation in response to the second challenge of ADP and AYPGKF was restored in GRK6−/− platelets whereas re-stimulation of the agonist failed to induce aggregation in WT platelets, indicating that GRK6 contributed to P2Y1, P2Y12, and PAR4 receptor desensitization. Furthermore, 2-MeSADP-induced Akt phosphorylation and AYPGKF-induced Akt, extracellular signal-related kinase (ERK), and protein kinase Cδ (PKCδ) phosphorylation were significantly potentiated in GRK6−/− platelets. Finally, GRK6−/− mice exhibited an enhanced and stable thrombus formation after FeCl3 injury to the carotid artery and shorter tail bleeding times, indicating that GRK6−/− mice were more susceptible to thrombosis and hemostasis. We conclude that GRK6 plays an important role in regulating platelet functional responses and thrombus formation through selective GPCR desensitization.
Collapse
Affiliation(s)
- Preeti Kumari Chaudhary
- College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (P.K.C.); (S.K.); (S.-H.L.); (K.-M.P.)
| | - Sanggu Kim
- College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (P.K.C.); (S.K.); (S.-H.L.); (K.-M.P.)
| | - Youngheun Jee
- College of Veterinary Medicine and Veterinary Medical Research Institute, Jeju National University, Jeju 63243, Korea;
| | - Seung-Hun Lee
- College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (P.K.C.); (S.K.); (S.-H.L.); (K.-M.P.)
| | - Kyung-Mee Park
- College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (P.K.C.); (S.K.); (S.-H.L.); (K.-M.P.)
| | - Soochong Kim
- College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (P.K.C.); (S.K.); (S.-H.L.); (K.-M.P.)
- Correspondence: ; Tel.: +82-43-249-1846
| |
Collapse
|
17
|
Signal profiling of the β 1AR reveals coupling to novel signalling pathways and distinct phenotypic responses mediated by β 1AR and β 2AR. Sci Rep 2020; 10:8779. [PMID: 32471984 PMCID: PMC7260363 DOI: 10.1038/s41598-020-65636-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 05/07/2020] [Indexed: 12/22/2022] Open
Abstract
A comprehensive understanding of signalling downstream of GPCRs requires a broad approach to capture novel signalling modalities in addition to established pathways. Here, using an array of sixteen validated BRET-based biosensors, we analyzed the ability of seven different β-adrenergic ligands to engage five distinct signalling pathways downstream of the β1-adrenergic receptor (β1AR). In addition to generating signalling signatures and capturing functional selectivity for the different ligands toward these pathways, we also revealed coupling to signalling pathways that have not previously been ascribed to the βAR. These include coupling to Gz and G12 pathways. The signalling cascade linking the β1AR to calcium mobilization was also characterized using a combination of BRET-based biosensors and CRISPR-engineered HEK 293 cells lacking the Gαs subunit or with pharmacological or genetically engineered pathway inhibitors. We show that both Gs and G12 are required for the full calcium response. Our work highlights the power of combining signal profiling with genome editing approaches to capture the full complement of GPCR signalling activities in a given cell type and to probe their underlying mechanisms.
Collapse
|
18
|
Heuberger DM, Schuepbach RA. Protease-activated receptors (PARs): mechanisms of action and potential therapeutic modulators in PAR-driven inflammatory diseases. Thromb J 2019; 17:4. [PMID: 30976204 PMCID: PMC6440139 DOI: 10.1186/s12959-019-0194-8] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 03/08/2019] [Indexed: 12/29/2022] Open
Abstract
Inflammatory diseases have become increasingly prevalent with industrialization. To address this, numerous anti-inflammatory agents and molecular targets have been considered in clinical trials. Among molecular targets, protease-activated receptors (PARs) are abundantly recognized for their roles in the development of chronic inflammatory diseases. In particular, several inflammatory effects are directly mediated by the sensing of proteolytic activity by PARs. PARs belong to the seven transmembrane domain G protein-coupled receptor family, but are unique in their lack of physiologically soluble ligands. In contrast with classical receptors, PARs are activated by N-terminal proteolytic cleavage. Upon removal of specific N-terminal peptides, the resulting N-termini serve as tethered activation ligands that interact with the extracellular loop 2 domain and initiate receptor signaling. In the classical pathway, activated receptors mediate signaling by recruiting G proteins. However, activation of PARs alternatively lead to the transactivation of and signaling through receptors such as co-localized PARs, ion channels, and toll-like receptors. In this review we consider PARs and their modulators as potential therapeutic agents, and summarize the current understanding of PAR functions from clinical and in vitro studies of PAR-related inflammation.
Collapse
Affiliation(s)
- Dorothea M Heuberger
- Institute of Intensive Care Medicine, University Hospital Zurich, University of Zurich, Zurich, Switzerland.,Surgical Research Division, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Reto A Schuepbach
- Institute of Intensive Care Medicine, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| |
Collapse
|
19
|
Suppression of RGSz1 function optimizes the actions of opioid analgesics by mechanisms that involve the Wnt/β-catenin pathway. Proc Natl Acad Sci U S A 2018; 115:E2085-E2094. [PMID: 29440403 DOI: 10.1073/pnas.1707887115] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Regulator of G protein signaling z1 (RGSz1), a member of the RGS family of proteins, is present in several networks expressing mu opioid receptors (MOPRs). By using genetic mouse models for global or brain region-targeted manipulations of RGSz1 expression, we demonstrated that the suppression of RGSz1 function increases the analgesic efficacy of MOPR agonists in male and female mice and delays the development of morphine tolerance while decreasing the sensitivity to rewarding and locomotor activating effects. Using biochemical assays and next-generation RNA sequencing, we identified a key role of RGSz1 in the periaqueductal gray (PAG) in morphine tolerance. Chronic morphine administration promotes RGSz1 activity in the PAG, which in turn modulates transcription mediated by the Wnt/β-catenin signaling pathway to promote analgesic tolerance to morphine. Conversely, the suppression of RGSz1 function stabilizes Axin2-Gαz complexes near the membrane and promotes β-catenin activation, thereby delaying the development of analgesic tolerance. These data show that the regulation of RGS complexes, particularly those involving RGSz1-Gαz, represents a promising target for optimizing the analgesic actions of opioids without increasing the risk of dependence or addiction.
Collapse
|
20
|
Coordination of platelet agonist signaling during the hemostatic response in vivo. Blood Adv 2017; 1:2767-2775. [PMID: 29296928 DOI: 10.1182/bloodadvances.2017009498] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 11/23/2017] [Indexed: 11/20/2022] Open
Abstract
The local microenvironment within an evolving hemostatic plug shapes the distribution of soluble platelet agonists, resulting in a gradient of platelet activation. We previously showed that thrombin activity at a site of vascular injury is spatially restricted, resulting in robust activation of a subpopulation of platelets in the hemostatic plug core. In contrast, adenosine 5'-diphosphate (ADP)/P2Y12 signaling contributes to the accumulation of partially activated, loosely packed platelets in a shell overlying the core. The contribution of the additional platelet agonists thromboxane A2 (TxA2) and epinephrine to this hierarchical organization was not previously shown. Using a combination of genetic and pharmacologic approaches coupled with real-time intravital imaging, we show that TxA2 signaling is critical and nonredundant with ADP/P2Y12 for platelet accumulation in the shell region but not required for full platelet activation in the hemostatic plug core, where thrombin activity is highest. In contrast, epinephrine signaling is dispensable even in the presence of a P2Y12 antagonist. Finally, dual P2Y12 and thrombin inhibition does not substantially inhibit hemostatic plug core formation any more than thrombin inhibition alone, providing further evidence that thrombin is the primary driver of platelet activation in this region. Taken together, these studies show for the first time how thrombin, P2Y12, and TxA2 signaling are coordinated during development of a hierarchical organization of hemostatic plugs in vivo and provide novel insights into the impact of dual antiplatelet therapy on hemostasis and thrombosis.
Collapse
|
21
|
Schaid MD, Wisinski JA, Kimple ME. The EP3 Receptor/G z Signaling Axis as a Therapeutic Target for Diabetes and Cardiovascular Disease. AAPS J 2017; 19:1276-1283. [PMID: 28584908 PMCID: PMC7934137 DOI: 10.1208/s12248-017-0097-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 05/05/2017] [Indexed: 12/25/2022] Open
Abstract
Cardiovascular disease is a common co-morbidity found with obesity-linked type 2 diabetes. Current pharmaceuticals for these two diseases treat each of them separately. Yet, diabetes and cardiovascular disease share molecular signaling pathways that are increasingly being understood to contribute to disease pathophysiology, particularly in pre-clinical models. This review will focus on one such signaling pathway: that mediated by the G protein-coupled receptor, Prostaglandin E2 Receptor 3 (EP3), and its associated G protein in the insulin-secreting beta-cell and potentially the platelet, Gz. The EP3/Gz signaling axis may hold promise as a dual target for type 2 diabetes and cardiovascular disease.
Collapse
Affiliation(s)
- Michael D Schaid
- Interdisciplinary Graduate Program in Nutritional Sciences, College of Agriculture and Life Sciences, University of Wisconsin-Madison, 4148 UW Medical Foundation Centennial Building, 1685 Highland Ave, Madison, Wisconsin, 53705, USA
- Research Service, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin, USA
| | - Jaclyn A Wisinski
- Research Service, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin, USA
- Department of Medicine, Division of Endocrinology, School of Medicine and Public Health, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Michelle E Kimple
- Interdisciplinary Graduate Program in Nutritional Sciences, College of Agriculture and Life Sciences, University of Wisconsin-Madison, 4148 UW Medical Foundation Centennial Building, 1685 Highland Ave, Madison, Wisconsin, 53705, USA.
- Research Service, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin, USA.
- Department of Medicine, Division of Endocrinology, School of Medicine and Public Health, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA.
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA.
| |
Collapse
|
22
|
Comprehensive comparison of neonate and adult human platelet transcriptomes. PLoS One 2017; 12:e0183042. [PMID: 28813466 PMCID: PMC5559076 DOI: 10.1371/journal.pone.0183042] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 07/30/2017] [Indexed: 12/21/2022] Open
Abstract
Understanding the underlying mechanisms of the well-substantiated platelet hyporeactivity in neonates is of interest given their implications for the clinical management of newborns, a population at higher bleeding risk than adults (especially sick and preterm infants), as well as for gaining insight into the regulatory mechanisms of platelet biology. Transcriptome analysis is useful in identifying mRNA signatures affecting platelet function. However, human fetal/neonatal platelet transcriptome analysis has never before been reported. We have used mRNA expression array for the first time to compare platelet transcriptome changes during development. Microarray analysis was performed in pure platelet RNA obtained from adult and cord blood, using the same platform in two independent laboratories. A high correlation was obtained between array results for both adult and neonate platelet samples. There was also good agreement between results in our adult samples and outcomes previously reported in three different studies. Gene enrichment analysis showed that immunity- and platelet function-related genes are highly expressed at both developmental stages. Remarkably, 201 genes were found to be differentially expressed throughout development. In particular, neonatal platelets contain higher levels of mRNA that are associated with protein synthesis and processing, while carrying significantly lower levels of genes involved in calcium transport/metabolism and cell signaling (including GNAZ). Overall, our results point to variations in platelet transcriptome as possibly underlining the hypo-functional phenotype of neonatal platelets and provide further support for the role of platelets in cellular immune response. Better characterization of the platelet transcriptome throughout development can contribute to elucidate how transcriptome changes impact different pathological conditions.
Collapse
|
23
|
de Queiroz MR, de Sousa BB, da Cunha Pereira DF, Mamede CCN, Matias MS, de Morais NCG, de Oliveira Costa J, de Oliveira F. The role of platelets in hemostasis and the effects of snake venom toxins on platelet function. Toxicon 2017; 133:33-47. [PMID: 28435120 DOI: 10.1016/j.toxicon.2017.04.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/12/2017] [Accepted: 04/19/2017] [Indexed: 12/09/2022]
Abstract
The human body has a set of physiological processes, known as hemostasis, which keeps the blood fluid and free of clots in normal vessels; in the case of vascular injury, this process induces the local formation of a hemostatic plug, preventing hemorrhage. The hemostatic system in humans presents complex physiological interactions that involve platelets, plasma proteins, endothelial and subendothelial structures. Disequilibrium in the regulatory mechanisms that control the growth and the size of the thrombus is one of the factors that favors the development of diseases related to vascular disorders such as myocardial infarction and stroke, which are among the leading causes of death in the western world. Interfering with platelet function is a strategy for the treatment of thrombotic diseases. Antiplatelet drugs are used mainly in cases related to arterial thrombosis and interfere in the formation of the platelet plug by different mechanisms. Aspirin (acetylsalicylic acid) is the oldest and most widely used antithrombotic drug. Although highly effective in most cases, aspirin has limitations compared to other drugs used in the treatment of homeostatic disorders. For this reason, research related to molecules that interfere with platelet aggregation are of great relevance. In this regard, snake venoms are known to contain a number of molecules that interfere with hemostasis, including platelet function. The mechanisms by which snake venom components inhibit or activate platelet aggregation are varied and can be used as tools for the diagnosis and the treatment of several hemostatic disorders. The aim of this review is to present the role of platelets in hemostasis and the mechanisms by which snake venom toxins interfere with platelet function.
Collapse
Affiliation(s)
- Mayara Ribeiro de Queiroz
- Instituto de Genética e Bioquímica, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil; Instituto Nacional de Ciência e Tecnologia em Nano-Biofarmacêutica (N-Biofar), Belo Horizonte, MG, Brazil
| | - Bruna Barbosa de Sousa
- Instituto de Genética e Bioquímica, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil; Instituto Nacional de Ciência e Tecnologia em Nano-Biofarmacêutica (N-Biofar), Belo Horizonte, MG, Brazil
| | | | - Carla Cristine Neves Mamede
- Instituto de Ciências Agrárias, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil; Instituto Nacional de Ciência e Tecnologia em Nano-Biofarmacêutica (N-Biofar), Belo Horizonte, MG, Brazil
| | - Mariana Santos Matias
- Instituto de Genética e Bioquímica, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil
| | | | - Júnia de Oliveira Costa
- Instituto Federal de Educação, Ciência e Tecnologia do Triângulo Mineiro, Ituiutaba, MG, Brazil
| | - Fábio de Oliveira
- Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil; Instituto Nacional de Ciência e Tecnologia em Nano-Biofarmacêutica (N-Biofar), Belo Horizonte, MG, Brazil.
| |
Collapse
|
24
|
Belleville-Rolland T, Sassi Y, Decouture B, Dreano E, Hulot JS, Gaussem P, Bachelot-Loza C. MRP4 (ABCC4) as a potential pharmacologic target for cardiovascular disease. Pharmacol Res 2016; 107:381-389. [PMID: 27063943 DOI: 10.1016/j.phrs.2016.04.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 04/02/2016] [Indexed: 01/13/2023]
Abstract
This review focuses on multidrug resistance protein 4 (MRP4 or ABCC4) that has recently been shown to play a role in cAMP homeostasis, a key-pathway in vascular biology and in platelet functions. In vascular system, recent data provide evidence that inhibition of MRP4 prevents human coronary artery smooth muscle cell proliferation in vitro and in vivo, as well as human pulmonary artery smooth muscle cell proliferation in vitro and pulmonary hypertension in mice in vivo. In the heart, MRP4 silencing in adult rat ventricular myocytes results in an increase in intracellular cAMP levels leading to enhanced cardiomyocyte contractility. However, a prolonged inhibition of MRP4 can promote cardiac hypertrophy. In addition, secreted cAMP, through its metabolite adenosine, prevents adrenergically induced cardiac hypertrophy and fibrosis. Finally, MRP4 inhibition in platelets induces a moderate thrombopathy. The localization of MRP4 underlines the emerging concept of cAMP compartmentalization in platelets, which is a major regulatory mechanism in other cells. cAMP storage in platelet dense granules might limit the cAMP cytosolic concentration upon adenylate cyclase activation, a necessary step to induce platelet activation. In this review, we discuss the therapeutic potential of direct pharmacological inhibition of MRP4 in atherothrombotic disease, via its vasodilating and antiplatelet effects.
Collapse
Affiliation(s)
- Tiphaine Belleville-Rolland
- Inserm UMR-S1140, Faculté de Pharmacie, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; AP-HP, Hôpital Européen Georges Pompidou, Service dhématologie biologique, Paris, France
| | - Yassine Sassi
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Benoit Decouture
- Inserm UMR-S1140, Faculté de Pharmacie, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Elise Dreano
- Inserm UMR-S1140, Faculté de Pharmacie, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jean-Sébastien Hulot
- AP-HP, Institute of Cardiometabolism and Nutrition (ICAN), Pitié-Salpêtrière Hospital, F-75013 Paris, France; Sorbonne Universités, UPMC Univ. Paris 06, France
| | - Pascale Gaussem
- Inserm UMR-S1140, Faculté de Pharmacie, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; AP-HP, Hôpital Européen Georges Pompidou, Service dhématologie biologique, Paris, France
| | - Christilla Bachelot-Loza
- Inserm UMR-S1140, Faculté de Pharmacie, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
| |
Collapse
|
25
|
Budnik I, Shenkman B, Savion N. Role of G protein signaling in the formation of the fibrin(ogen)–integrin αIIbβ3–actin cytoskeleton complex in platelets. Platelets 2016; 27:563-75. [DOI: 10.3109/09537104.2016.1147544] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Ivan Budnik
- Goldschleger Eye Research Institute and the Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Pathophysiology, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Boris Shenkman
- National Hemophilia Center, Sheba Medical Center, Tel-Hashomer, Israel
| | - Naphtali Savion
- Goldschleger Eye Research Institute and the Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
26
|
Gpr176 is a Gz-linked orphan G-protein-coupled receptor that sets the pace of circadian behaviour. Nat Commun 2016; 7:10583. [PMID: 26882873 PMCID: PMC4757782 DOI: 10.1038/ncomms10583] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 12/30/2015] [Indexed: 01/26/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) participate in a broad range of physiological functions. A priority for fundamental and clinical research, therefore, is to decipher the function of over 140 remaining orphan GPCRs. The suprachiasmatic nucleus (SCN), the brain's circadian pacemaker, governs daily rhythms in behaviour and physiology. Here we launch the SCN orphan GPCR project to (i) search for murine orphan GPCRs with enriched expression in the SCN, (ii) generate mutant animals deficient in candidate GPCRs, and (iii) analyse the impact on circadian rhythms. We thereby identify Gpr176 as an SCN-enriched orphan GPCR that sets the pace of circadian behaviour. Gpr176 is expressed in a circadian manner by SCN neurons, and molecular characterization reveals that it represses cAMP signalling in an agonist-independent manner. Gpr176 acts independently of, and in parallel to, the Vipr2 GPCR, not through the canonical Gi, but via the unique G-protein subclass Gz. The suprachiasmatic nucleus (SCN) is the central regulator of circadian rhythms. Here the authors identify mouse Gpr176 as a pace modulator of this circadian clock and characterize its mode of action as coupling to Gz rather than Gi subunits.
Collapse
|
27
|
Friedman EA, Ogletree ML, Haddad EV, Boutaud O. Understanding the role of prostaglandin E2 in regulating human platelet activity in health and disease. Thromb Res 2015; 136:493-503. [PMID: 26077962 DOI: 10.1016/j.thromres.2015.05.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 05/05/2015] [Accepted: 05/25/2015] [Indexed: 01/14/2023]
Abstract
The platelet thrombus is the major pathologic entity in acute coronary syndromes, and antiplatelet agents are a mainstay of therapy. However, individual patient responsiveness to current antiplatelet drugs is variable, and all drugs carry a risk of bleeding. An understanding of the complex role of Prostaglandin E2 (PGE2) in regulating thrombosis offers opportunities for the development of novel individualized antiplatelet treatment. However, deciphering the platelet regulatory function of PGE2 has long been confounded by non-standardized experimental conditions, extrapolation of murine data to humans, and phenotypic differences in PGE2 response. This review synthesizes past and current knowledge about PGE2 effects on platelet biology, presents a rationale for standardization of experimental protocols, and provides insight into a molecular mechanism by which PGE2-activated pathways could be targeted for new personalized antiplatelet therapy to inhibit pathologic thrombosis without affecting hemostasis.
Collapse
Affiliation(s)
- Eitan A Friedman
- Department of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Martin L Ogletree
- PO Box 559, Bala Cynwyd, PA 19004; Department of Pharmacology, Vanderbilt University, Nashville, TN 37232
| | - Elias V Haddad
- Department of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Olivier Boutaud
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232.
| |
Collapse
|
28
|
Vemana HP, Karim ZA, Conlon C, Khasawneh FT. A critical role for the transient receptor potential channel type 6 in human platelet activation. PLoS One 2015; 10:e0125764. [PMID: 25928636 PMCID: PMC4416038 DOI: 10.1371/journal.pone.0125764] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/25/2015] [Indexed: 12/31/2022] Open
Abstract
While calcium signaling is known to play vital roles in platelet function, the mechanisms underlying its receptor-operated calcium entry component (ROCE) remain poorly understood. It has been proposed, but never proven in platelets, that the canonical transient receptor potential channel-6 (TRPC6) mediates ROCE. Nonetheless, we have previously shown that the mouse TRPC6 regulates hemostasis, thrombogenesis by regulating platelet aggregation. In the present studies, we used a pharmacological approach to characterize the role of TRPC6 in human platelet biology. Thus, interestingly, we observed that a TRPC6 inhibitor exerted significant inhibitory effects on human platelet aggregation in a thromboxane receptor (TPR)-selective manner; no additional inhibition was observed in the presence of the calcium chelator BAPTA. This inhibitor also significantly inhibited human platelet secretion (dense and alpha granules), integrin IIb-IIIa, Akt and ERK phosphorylation, again, in a TPR-selective manner; no effects were observed in response to ADP receptor stimulation. Furthermore, there was a causal relationship between these inhibitory effects, and the capacity of the TRPC6 inhibitor to abrogate elevation in intracellular calcium, that was again found to be TPR-specific. This effect was not found to be due to antagonism of TPR, as the TRPC6 inhibitor did not displace the radiolabeled antagonist [3H]SQ29,548 from its binding sites. Finally, our studies also revealed that TRPC6 regulates human clot retraction, as well as physiological hemostasis and thrombus formation, in mice. Taken together, our findings demonstrate, for the first time, that TRPC6 directly regulates TPR-dependent ROCE and platelet function. Moreover, these data highlight TRPC6 as a novel promising therapeutic strategy for managing thrombotic disorders.
Collapse
Affiliation(s)
- Hari Priya Vemana
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California, United States of America
| | - Zubair A. Karim
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California, United States of America
| | - Christine Conlon
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California, United States of America
| | - Fadi T. Khasawneh
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California, United States of America
- * E-mail:
| |
Collapse
|
29
|
Inamdar V, Patel A, Manne BK, Dangelmaier C, Kunapuli SP. Characterization of UBO-QIC as a Gαq inhibitor in platelets. Platelets 2015; 26:771-8. [PMID: 25734215 DOI: 10.3109/09537104.2014.998993] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Gαq plays an important role in platelet activation by agonists such as thrombin, adenosine diphosphate (ADP) and thromboxane. The significance of Gαq signaling in platelets was established using YM254890, a Gαq/11-specific inhibitor and Gαq knockout murine platelets. However, YM-254890 is no longer available for investigators and there is a need to characterize other Gαq inhibitors. The aim of this study is to characterize the specificity of a compound, {L-threonine,(3R)-N-acetyl-3-hydroxy-L-leucyl-(aR)-a-hydroxybenzenepropanoyl-2,3-idehydro-N-methylalanyl-L-alanyl-N-methyl-L-alanyl-(3R)-3-[[(2S,3R)-3-hydroxy-4-methyl-1-oxo-2-[(1-oxopropyl)amino]pentyl]oxy]-L-leucyl-N,O-dimethyl-,(7 → 1)-lactone (9CI)} (UBO-QIC), as a Gαq inhibitor in platelets. Human platelets treated with UBO-QIC showed a concentration-dependent inhibition of platelet aggregation and secretion by protease-activated receptors (PAR) agonists, U46619 and ADP. UBO-QIC also abolished Gαq pathway signaling events such as calcium mobilization and pleckstrin phosphorylation. UBO-QIC had no nonspecific effects on the Gα12/13 pathway since platelet shape change was intact in Gαq knockout murine platelets stimulated with PAR agonists in the presence of the inhibitor. In addition, UBO-QIC-treated platelets did not affect collagen-related peptide-induced platelet activation suggesting that this inhibitor had no non-specific effects on the GPVI pathway. Furthermore, Akt phosphorylation downstream of the Gαi and Gαz pathways, and vasodilator-stimulated phosphoprotein phosphorylation downstream of the Gαs pathway were not inhibited in UBO-QIC-treated platelets. UBO-QIC is a specific inhibitor for Gαq, which can be a useful tool for investigating Gαq-coupled receptor signaling pathways in platelets.
Collapse
Affiliation(s)
- Vaishali Inamdar
- a Sol Sherry Thrombosis Research Center and Department of Physiology , Temple University School of Medicine , Philadelphia , PA , USA
| | - Akruti Patel
- a Sol Sherry Thrombosis Research Center and Department of Physiology , Temple University School of Medicine , Philadelphia , PA , USA
| | - Bhanu Kanth Manne
- a Sol Sherry Thrombosis Research Center and Department of Physiology , Temple University School of Medicine , Philadelphia , PA , USA
| | - Carol Dangelmaier
- a Sol Sherry Thrombosis Research Center and Department of Physiology , Temple University School of Medicine , Philadelphia , PA , USA
| | - Satya P Kunapuli
- a Sol Sherry Thrombosis Research Center and Department of Physiology , Temple University School of Medicine , Philadelphia , PA , USA
| |
Collapse
|
30
|
Abstract
The myenteric plexus of the enteric nervous system controls the movement of smooth muscles in the gastrointestinal system. They extend their axons between two peripheral smooth muscle layers to form a tubular meshwork arborizing the gut wall. How a tubular axonal meshwork becomes established without invading centrally toward the gut epithelium has not been addressed. We provide evidence here that sonic hedgehog (Shh) secreted from the gut epithelium prevents central projections of enteric axons, thereby forcing their peripheral tubular distribution. Exclusion of enteric central projections by Shh requires its binding partner growth arrest specific gene 1 (Gas1) and its signaling component smoothened (Smo) in enteric neurons. Using enteric neurons differentiated from neurospheres in vitro, we show that enteric axon growth is not inhibited by Shh. Rather, when Shh is presented as a point source, enteric axons turn away from it in a Gas1-dependent manner. Of the Gαi proteins that can couple with Smo, G protein α Z (Gnaz) is found in enteric axons. Knockdown and dominant negative inhibition of Gnaz dampen the axon-repulsive response to Shh, and Gnaz mutant intestines contain centrally projected enteric axons. Together, our data uncover a previously unsuspected mechanism underlying development of centrifugal tubular organization and identify a previously unidentified effector of Shh in axon guidance.
Collapse
|
31
|
Doyle GA, Schwebel CL, Ruiz SE, Chou AD, Lai AT, Wang MJ, Smith GG, Buono RJ, Berrettini WH, Ferraro TN. Analysis of candidate genes for morphine preference quantitative trait locus Mop2. Neuroscience 2014; 277:403-16. [PMID: 25058503 DOI: 10.1016/j.neuroscience.2014.07.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 07/14/2014] [Accepted: 07/14/2014] [Indexed: 11/26/2022]
Abstract
Compared to DBA/2J (D2), C57BL/6J (B6) inbred mice exhibit strong morphine preference when tested using a two-bottle choice drinking paradigm. A morphine preference quantitative trait locus (QTL), Mop2, was originally mapped to proximal chromosome (Chr) 10 using a B6xD2 F2 intercross population, confirmed with reciprocal congenic strains and fine mapped with recombinant congenic strains. These efforts identified a ∼ 10-Million base pair (Mbp) interval, underlying Mop2, containing 35 genes. To further reduce the interval, mice from the D2.B6-Mop2-P1 congenic strain were backcrossed to parental D2 mice and two new recombinant strains of interest were generated: D2.B6-Mop2-P1.pD.dB and D2.B6-Mop2-P1.pD.dD. Results obtained from testing these strains in the two-bottle choice drinking paradigm suggest that the gene(s) responsible for the Mop2 QTL is one or more of 22 remaining within the newly defined interval (∼ 7.6 Mbp) which includes Oprm1 and several other genes related to opioid pharmacology. Real-time qRT-PCR analysis of Oprm1 and opioid-related genes Rgs17, Ppp1r14c, Vip, and Iyd revealed both between-strain and within-strain expression differences in comparisons of saline- and morphine-treated B6 and D2 mice. Analysis of Rgs17 protein levels also revealed both between-strain and within-strain differences in comparisons of saline- and morphine-treated B6 and D2 mice. Results suggest that the Mop2 QTL represents the combined influence of multiple genetic variants on morphine preference in these two strains. Relative contributions of each variant remain to be determined.
Collapse
Affiliation(s)
- G A Doyle
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
| | - C L Schwebel
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - S E Ruiz
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - A D Chou
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - A T Lai
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - M-J Wang
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - G G Smith
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA; Research Services, Department of Veterans Affairs Medical Center, Coatesville, PA, USA
| | - R J Buono
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ, USA
| | - W H Berrettini
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - T N Ferraro
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA; Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ, USA
| |
Collapse
|
32
|
Moore SF, Hunter RW, Hers I. Protein kinase C and P2Y12 take center stage in thrombin-mediated activation of mammalian target of rapamycin complex 1 in human platelets. J Thromb Haemost 2014; 12:748-60. [PMID: 24612393 PMCID: PMC4238809 DOI: 10.1111/jth.12552] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 02/25/2014] [Indexed: 01/24/2023]
Abstract
BACKGROUND Rapamycin, an inhibitor of mammalian target of rapamycin complex-1 (mTORC1), reduces platelet spreading, thrombus stability, and clot retraction. Despite an important role of mTORC1 in platelet function, little is known about how it is regulated. The objective of this study was to determine the signaling pathways that regulate mTORC1 in human platelets. METHODS Mammalian target of rapamycin complex-1 activation was assessed by measuring the phosphorylation of its downstream substrate ribosomal S6 kinase 1 (p70S6K). RESULTS Thrombin or the protein kinase C (PKC) activator phorbal 12-myristate 13-acetate stimulated activation of mTORC1 in a PKC-dependent, Akt-independent manner that correlated with phosphorylation of tuberin/tuberous sclerosis 2 (TSC2) (Ser939 and Thr1462). In contrast, insulin-like growth factor 1 (IGF-1)-stimulated TSC2 phosphorylation was completely dependent on phosphoinositide 3 kinase (PI3 kinase)/Akt but did not result in any detectable mTORC1 activation. Early (Ser939 and Thr1462) and late (Thr1462) TSC2 phosphorylation in response to thrombin were directly PKC dependent, whereas later TSC2 (Ser939) and p70S6K phosphorylation were largely dependent on paracrine signaling through P2Y(12). PKC-mediated adenosine diphosphate (ADP) secretion was essential for thrombin-stimulated mTORC1 activation, as (i) ADP rescued p70S6K phosphorylation in the presence of a PKC inhibitor and (ii) P2Y(12) antagonism prevented thrombin-mediated mTORC1 activation. Rescue of mTORC1 activation with exogenous ADP was completely dependent on the Src family kinases but independent of PI3 kinase/Akt. Interestingly, although inhibition of Src blocked the ADP rescue, it had little effect on thrombin-stimulated p70S6K phosphorylation under conditions where PKC was not inhibited. CONCLUSION These results demonstrate that thrombin activates the mTORC1 pathway in human platelets through PKC-mediated ADP secretion and subsequent activation of P2Y(12), in a manner largely independent of the canonical PI3 kinase/Akt pathway.
Collapse
Affiliation(s)
- S F Moore
- School of Physiology and Pharmacology, Medical Sciences Building, University of Bristol, Bristol, UK
| | | | | |
Collapse
|
33
|
Ultrastructure of Intervertebral Disc and Vertebra-Disc Junctions Zones as a Link in Etiopathogenesis of Idiopathic Scoliosis. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/850594] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Background Context. There is no general accepted theory on the etiology of idiopathic scoliosis (IS). An important role of the vertebrae endplate physes (VEPh) and intervertebral discs (IVD) in spinal curve progression is acknowledged, but ultrastructural mechanisms are not well understood. Purpose. To analyze the current literature on ultrastructural characteristics of VEPh and IVD in the context of IS etiology. Study Design/Setting. A literature review. Results. There is strong evidence for multifactorial etiology of IS. Early wedging of vertebra bodies is likely due to laterally directed appositional bone growth at the concave side, caused by a combination of increased cell proliferation at the vertebrae endplate and altered mechanical properties of the outer annulus fibrosus of the adjacent IVD. Genetic defects in bending proteins necessary for IVD lamellar organization underlie altered mechanical properties. Asymmetrical ligaments, muscular stretch, and spine instability may also play roles in curve formation. Conclusions. Development of a reliable, cost effective method for identifying patients at high risk for curve progression is needed and could lead to a paradigm shift in treatment options. Unnecessary anxiety, bracing, and radiation could potentially be minimized and high risk patient could receive surgery earlier, rendering better outcomes with fewer fused segments needed to mitigate curve progression.
Collapse
|
34
|
Hultman R, Kumari U, Michel N, Casey PJ. Gαz regulates BDNF-induction of axon growth in cortical neurons. Mol Cell Neurosci 2013; 58:53-61. [PMID: 24321455 DOI: 10.1016/j.mcn.2013.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 11/27/2013] [Accepted: 12/03/2013] [Indexed: 01/26/2023] Open
Abstract
The disruption of neurotransmitter and neurotrophic factor signaling in the central nervous system (CNS) is implicated as the root cause of neuropsychiatric disorders, including schizophrenia, epilepsy, chronic pain, and depression. Therefore, identifying the underlying molecular mechanisms by which neurotransmitter and neurotrophic factor signaling regulates neuronal survival or growth may facilitate identification of more effective therapies for these disorders. Previously, our lab found that the heterotrimeric G protein, Gz, mediates crosstalk between G protein-coupled receptors and neurotrophin signaling in the neural cell line PC12. These data, combined with Gαz expression profiles--predominantly in neuronal cells with higher expression levels corresponding to developmental times of target tissue innervation--suggested that Gαz may play an important role in neurotrophin signaling and neuronal development. Here, we provide evidence in cortical neurons, both manipulated ex vivo and those cultured from Gz knockout mice, that Gαz is localized to axonal growth cones and plays a significant role in the development of axons of cortical neurons in the CNS. Our findings indicate that Gαz inhibits BDNF-stimulated axon growth in cortical neurons, establishing an endogenous role for Gαz in regulating neurotrophin signaling in the CNS.
Collapse
Affiliation(s)
- Rainbo Hultman
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA; Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Republic of Singapore
| | - Udhaya Kumari
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Republic of Singapore
| | - Nadine Michel
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Patrick J Casey
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Republic of Singapore.
| |
Collapse
|
35
|
Activation of Hedgehog signaling by loss of GNAS causes heterotopic ossification. Nat Med 2013; 19:1505-12. [PMID: 24076664 PMCID: PMC3917515 DOI: 10.1038/nm.3314] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 07/19/2013] [Indexed: 12/17/2022]
Abstract
Bone formation is exquisitely controlled in space and time. Heterotopic ossification (HO), the pathologic formation of extra-skeletal bone, occurs as a common complication of trauma or in genetic disorders and can be disabling and lethal. However, the underlying molecular mechanisms are largely unknown. Here we demonstrate that Gαs restricts bone formation to the skeleton by inhibiting Hedgehog (Hh) signaling in mesenchymal progenitor cells. In progressive osseous heteroplasia (POH), a human disease caused by null mutations in GNAS that encodes Gαs, HH signaling is upregulated in ectopic osteoblasts and progenitor cells. Ectopic Hh signaling is sufficient to induce HO, while Hh signaling inhibition blocks HO in animal models. As our previous work has shown that GNAS gain of function mutations upregulate WNT/β-Catenin signaling in fibrous dysplasia (FD), our findings identify Gαs as a critical regulator of osteoblast differentiation by maintaining a balance between two key signaling pathways: Wnt/β-catenin and Hh. HH signaling inhibitors developed for cancer therapy may be repurposed to treat HO and other diseases caused by GNAS inactivation.
Collapse
|
36
|
Brass LF, Tomaiuolo M, Stalker TJ. Harnessing the platelet signaling network to produce an optimal hemostatic response. Hematol Oncol Clin North Am 2013; 27:381-409. [PMID: 23714305 DOI: 10.1016/j.hoc.2013.02.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Once released into the circulation by megakaryocytes, circulating platelets can undergo rapid activation at sites of vascular injury and resist unwarranted activation, which can lead to heart attacks and strokes. Historically, the signaling mechanisms underlying the regulation of platelet activation have been approached as a collection of individual pathways unique to agonist. This review takes a different approach, casting platelet activation as the product of a signaling network, in which activating and restraining mechanisms interact in a flexible network that regulates platelet adhesiveness, cohesion between platelets, granule secretion, and the formation of a stable hemostatic thrombus.
Collapse
Affiliation(s)
- Lawrence F Brass
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
| | | | | |
Collapse
|
37
|
Moheimani F, Jackson DE. P2Y12 receptor: platelet thrombus formation and medical interventions. Int J Hematol 2012; 96:572-87. [PMID: 23054651 DOI: 10.1007/s12185-012-1188-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 09/20/2012] [Accepted: 09/20/2012] [Indexed: 12/14/2022]
Abstract
Platelets express a wide range of receptors and proteins that play essential roles in thrombus formation. Among these, the P2Y(12) receptor, a member of the G protein-coupled receptor family, has attracted a significant amount of attention. Stimulation of the P2Y(12) receptor by ADP results in activation of various signaling pathways involved in amplification of platelet activation and aggregation. There have been extensive attempts to design an ideal antithrombotic agent to block P2Y(12), which shows selective expression, as an intervention for cardiovascular disease. Current inhibitors of the P2Y(12) receptor include indirect inhibitor members of the thienopyridine family (ticlopidine, clopidogrel, and prasugrel), and direct P2Y(12) inhibitors (ticagrelor, cangrelor and elinogrel). Of these, clopidogrel is the most commonly prescribed P2Y(12) blocker; however, this product does not fulfill the ideal therapeutic requirements. The main limitations of clopidogrel administration include slow onset, prevention of recovery of platelet functions, and interindividual variability. Hence, advanced studies have been carried out to achieve more efficient and safer P2Y(12) blockade. In this review, we provide a brief but comprehensive report on P2Y(12), its role on platelet thrombus formation, and the targeting of this receptor as an intervention for cardiovascular disease, for the benefit of basic science and clinical researchers.
Collapse
Affiliation(s)
- Fatemeh Moheimani
- Thrombosis and Vascular Diseases Laboratory, Health Innovations Research Institute, School of Medical Sciences, RMIT University, PO Box 71, Bundoora, Melbourne, VIC 3083, Australia.
| | | |
Collapse
|
38
|
Kimple ME, Moss JB, Brar HK, Rosa TC, Truchan NA, Pasker RL, Newgard CB, Casey PJ. Deletion of GαZ protein protects against diet-induced glucose intolerance via expansion of β-cell mass. J Biol Chem 2012; 287:20344-55. [PMID: 22457354 DOI: 10.1074/jbc.m112.359745] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Insufficient plasma insulin levels caused by deficits in both pancreatic β-cell function and mass contribute to the pathogenesis of type 2 diabetes. This loss of insulin-producing capacity is termed β-cell decompensation. Our work is focused on defining the role(s) of guanine nucleotide-binding protein (G protein) signaling pathways in regulating β-cell decompensation. We have previously demonstrated that the α-subunit of the heterotrimeric G(z) protein, Gα(z), impairs insulin secretion by suppressing production of cAMP. Pancreatic islets from Gα(z)-null mice also exhibit constitutively increased cAMP production and augmented glucose-stimulated insulin secretion, suggesting that Gα(z) is a tonic inhibitor of adenylate cyclase, the enzyme responsible for the conversion of ATP to cAMP. In the present study, we show that mice genetically deficient for Gα(z) are protected from developing glucose intolerance when fed a high fat (45 kcal%) diet. In these mice, a robust increase in β-cell proliferation is correlated with significantly increased β-cell mass. Further, an endogenous Gα(z) signaling pathway, through circulating prostaglandin E activating the EP3 isoform of the E prostanoid receptor, appears to be up-regulated in insulin-resistant, glucose-intolerant mice. These results, along with those of our previous work, link signaling through Gα(z) to both major aspects of β-cell decompensation: insufficient β-cell function and mass.
Collapse
Affiliation(s)
- Michelle E Kimple
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705, USA.
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Abstract
This chapter summarizes current ideas about the intracellular signaling that drives platelet responses to vascular injury. After a brief overview of platelet activation intended to place the signaling pathways into context, the first section considers the early events of platelet activation leading up to integrin activation and platelet aggregation. The focus is on the G protein-mediated events utilized by agonists such as thrombin and ADP, and the tyrosine kinase-based signaling triggered by collagen. The second section considers the events that occur after integrin engagement, some of which are dependent on close physical contact between platelets. A third section addresses the regulatory events that help to avoid unprovoked or excessive platelet activation, after which the final section briefly considers individual variations in platelet reactivity and the role of platelet signaling in the innate immune response and embryonic development.
Collapse
Affiliation(s)
- Timothy J Stalker
- Departments of Medicine and Pharmacology, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | | | | |
Collapse
|
40
|
Valdizán EM, Díaz A, Pilar-Cuéllar F, Lantero A, Mostany R, Villar AV, Laorden ML, Hurlé MA. Chronic treatment with the opioid antagonist naltrexone favours the coupling of spinal cord μ-opioid receptors to Gαz protein subunits. Neuropharmacology 2011; 62:757-64. [PMID: 21903117 DOI: 10.1016/j.neuropharm.2011.08.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 08/03/2011] [Accepted: 08/19/2011] [Indexed: 11/30/2022]
Abstract
Sustained administration of opioid antagonists to rodents results in an enhanced antinociceptive response to agonists. We investigated the changes in spinal μ-opioid receptor signalling underlying this phenomenon. Rats received naltrexone (120 μg/h; 7 days) via osmotic minipumps. The antinociceptive response to the μ-agonist sufentanil was tested 24 h after naltrexone withdrawal. In spinal cord samples, we determined the interaction of μ-receptors with Gα proteins (agonist-stimulated [(35)S]GTPγS binding and immunoprecipitation of [(35)S]GTPγS-labelled Gα subunits) as well as μ-opioid receptor-dependent inhibition of the adenylyl cyclase (AC) activity. Chronic naltrexone treatment augmented DAMGO-stimulated [(35)S]GTPγS binding, potentiated the inhibitory effect of DAMGO on the AC/cAMP pathway, and increased the inverse agonist effect of naltrexone on cAMP accumulation. In control rats, the inhibitory effect of DAMGO on cAMP production was antagonized by pertussis toxin (PTX) whereas, after chronic naltrexone, the effect became resistant to the toxin, suggesting a coupling of μ-receptors to PTX-insensitive Gα(z) subunits. Immunoprecipitation assays confirmed the transduction switch from Gα(i/o) to Gα(z) proteins. The consequence was an enhancement of the antinociceptive response to sufentanil that, in consonance with the neurochemical data, was prevented by Gα(z)-antisense oligodeoxyribonucleotides but not by PTX. Such changes in opioid receptor signalling can be a double-edged sword. On the one hand, they may have potential applicability to the optimisation of the analgesic effects of opioid drugs for the control of pain. On the other hand, they represent an important homeostatic dysregulation of the endogenous opioid system that might account for undesirable effects in patients chronically treated with opioid antagonists. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.
Collapse
Affiliation(s)
- Elsa M Valdizán
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad de Cantabria, 39011 Santander, Cantabria, Spain
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Brass LF, Wannemacher KM, Ma P, Stalker TJ. Regulating thrombus growth and stability to achieve an optimal response to injury. J Thromb Haemost 2011; 9 Suppl 1:66-75. [PMID: 21781243 PMCID: PMC3422128 DOI: 10.1111/j.1538-7836.2011.04364.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
An optimal platelet response to injury can be defined as one in which blood loss is restrained and haemostasis is achieved without the penalty of further tissue damage caused by unwarranted vascular occlusion. This brief review considers some of the ways in which thrombus growth and stability can be regulated so that an optimal platelet response can be achieved in vivo. Three related topics are considered. The first focuses on intracellular mechanisms that regulate the early events of platelet activation downstream of G protein coupled receptors for agonists such as thrombin, thromboxane A(2) and ADP. The second considers the ways in which signalling events that are dependent on stable contacts between platelets can influence the state of platelet activation and thus affect thrombus growth and stability. The third focuses on the changes that are experienced by platelets as they move from their normal environment in freely-flowing plasma to a very different environment within the growing haemostatic plug, an environment in which the narrowing gaps and junctions between platelets not only facilitate communication, but also increasingly limit both the penetration of plasma and the exodus of platelet-derived bioactive molecules.
Collapse
Affiliation(s)
- L F Brass
- Department of Medicine and Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | | | | | | |
Collapse
|
42
|
Sagdilek E, Korkmaz A, Oter S, Avcu F, Topal T, Ozler M, Uysal B, Nevruz O, Beyan C, Ozluk K. The Similarity Between Aspirin Treatment and the Lack of Response to Epinephrine and the Frequency of Aspirin Resistance in Healthy Males. Clin Appl Thromb Hemost 2011; 17:202-7. [DOI: 10.1177/1076029609356425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objectives: The lack of response of platelets against epinephrine has been discovered with a frequency of 14% to 40% in previous studies. There are studies that have demonstrated the effect of aspirin on platelets may resemble the lack of response to epinephrine. In this study, the extent of the effects of aspirin treatment on aggregation and secretion in healthy males with a lack of response to epinephrine and the frequency of aspirin resistance were investigated. Methods: Blood samples were collected at the beginning and at the end of a 10-day aspirin usage in 52 healthy males. Epinephrine, adenosine diphosphate (ADP), collagen, arachidonic acid (AA) and thrombin aggregations, and adenosine triphosphate (ATP) secretion were studied. Participants were assigned to nonresponder (<20%), semiresponder (20%-60%), and responder (>60%) groups, depending on their maximum aggregation responses to epinephrine. Participants who displayed an aggregation to AA at the end of the aspirin treatment were accepted to be aspirin resistant. Results: Of the 52 participants, 4 were found to be nonresponders and 3 of 52 of the participants were found to be semiresponders. Although the lack of response to epinephrine and aspirin treatment displayed similarities in aggregations using epinephrine, ADP, collagen, and thrombin, they differed in aggregations using AA and for ATP secretion. The ratio of aspirin resistance was determined to be 4:52. Conclusions: The observation of AA aggregation in the participants with a lack of response to epinephrine demonstrates that epinephrine nonresponse cannot substitute aspirin treatment. The fact that aspirin resistance is observed in healthy males supports the view that aspirin resistance exists even before the first usage.
Collapse
Affiliation(s)
- Engin Sagdilek
- Department of Biophysics, Ege University, Faculty of Medicine, Izmir, Turkey, Department of Physiology, Gulhane Military Medical Academy, School of Medicine, Ankara, Turkey,
| | - Ahmet Korkmaz
- Department of Physiology, Gulhane Military Medical Academy, School of Medicine, Ankara, Turkey
| | - Sukru Oter
- Department of Physiology, Gulhane Military Medical Academy, School of Medicine, Ankara, Turkey
| | - Ferit Avcu
- Department of Haematology, Gulhane Military Medical Academy, School of Medicine, Ankara, Turkey
| | - Turgut Topal
- Department of Physiology, Gulhane Military Medical Academy, School of Medicine, Ankara, Turkey
| | - Mehmet Ozler
- Department of Physiology, Gulhane Military Medical Academy, School of Medicine, Ankara, Turkey
| | - Bulent Uysal
- Department of Physiology, Gulhane Military Medical Academy, School of Medicine, Ankara, Turkey
| | - Oral Nevruz
- Department of Haematology, Gulhane Military Medical Academy, School of Medicine, Ankara, Turkey
| | - Cengiz Beyan
- Department of Haematology, Gulhane Military Medical Academy, School of Medicine, Ankara, Turkey
| | - Kasim Ozluk
- Department of Physiology, Uludag University, Faculty of Medicine, Bursa, Turkey
| |
Collapse
|
43
|
Bellido-Martín L, Chen V, Jasuja R, Furie B, Furie BC. Imaging fibrin formation and platelet and endothelial cell activation in vivo. Thromb Haemost 2011; 105:776-82. [PMID: 21437353 DOI: 10.1160/th10-12-0771] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Accepted: 02/04/2011] [Indexed: 11/05/2022]
Abstract
Over the past six decades research employing in vitro assays has identified enzymes, cofactors, cell receptors and associated ligands important to the haemostatic process and its regulation. These studies have greatly advanced our understanding of the molecular and cellular bases of haemostasis and thrombosis. However, in vitro assays cannot simultaneously reproduce the interactions of all of the components of the haemostatic process that occur in vivo nor do they reflect the importance of haemodynamic factors resulting from blood flow. To overcome these limitations investigators have increasingly turned to animal models of haemostasis and thrombosis. In this article we describe some advances in the visualisation of platelet and endothelial cell activation and blood coagulation in vivo and review what we have learned from our intravital microscopy experiments using primarily the laser-induced injury model for thrombosis.
Collapse
Affiliation(s)
- L Bellido-Martín
- Division of Hemostasis and Thrombosis, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachussetts, USA
| | | | | | | | | |
Collapse
|
44
|
Mahaut-Smith MP, Jones S, Evans RJ. The P2X1 receptor and platelet function. Purinergic Signal 2011; 7:341-56. [PMID: 21484087 PMCID: PMC3166991 DOI: 10.1007/s11302-011-9224-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 02/22/2011] [Indexed: 12/17/2022] Open
Abstract
Extracellular nucleotides are ubiquitous signalling molecules, acting via the P2 class of surface receptors. Platelets express three P2 receptor subtypes, ADP-dependent P2Y1 and P2Y12 G-protein-coupled receptors and the ATP-gated P2X1 non-selective cation channel. Platelet P2X1 receptors can generate significant increases in intracellular Ca(2+), leading to shape change, movement of secretory granules and low levels of α(IIb)β(3) integrin activation. P2X1 can also synergise with several other receptors to amplify signalling and functional events in the platelet. In particular, activation of P2X1 receptors by ATP released from dense granules amplifies the aggregation responses to low levels of the major agonists, collagen and thrombin. In vivo studies using transgenic murine models show that P2X1 receptors amplify localised thrombosis following damage of small arteries and arterioles and also contribute to thromboembolism induced by intravenous co-injection of collagen and adrenaline. In vitro, under flow conditions, P2X1 receptors contribute more to aggregate formation on collagen-coated surfaces as the shear rate is increased, which may explain their greater contribution to localised thrombosis in arterioles compared to venules within in vivo models. Since shear increases substantially near sites of stenosis, anti-P2X1 therapy represents a potential means of reducing thrombotic events at atherosclerotic plaques.
Collapse
Affiliation(s)
- Martyn P Mahaut-Smith
- Department of Cell Physiology and Pharmacology, University of Leicester, Leicester, LE1 9HN, UK,
| | | | | |
Collapse
|
45
|
Abstract
MicroRNAs (miRNAs) regulate cell physiology by altering protein expression, but the biology of platelet miRNAs is largely unexplored. We tested whether platelet miRNA levels were associated with platelet reactivity by genome-wide profiling using platelet RNA from 19 healthy subjects. We found that human platelets express 284 miRNAs. Unsupervised hierarchical clustering of miRNA profiles resulted in 2 groups of subjects that appeared to cluster by platelet aggregation phenotypes. Seventy-four miRNAs were differentially expressed (DE) between subjects grouped according to platelet aggregation to epinephrine, a subset of which predicted the platelet reactivity response. Using whole genome mRNA expression data on these same subjects, we computationally generated a high-priority list of miRNA-mRNA pairs in which the DE platelet miRNAs had binding sites in 3'-untranslated regions of DE mRNAs, and the levels were negatively correlated. Three miRNA-mRNA pairs (miR-200b:PRKAR2B, miR-495:KLHL5, and miR-107:CLOCK) were selected from this list, and all 3 miRNAs knocked down protein expression from the target mRNA. Reduced activation from platelets lacking PRKAR2B supported these findings. In summary, (1) platelet miRNAs are able to repress expression of platelet proteins, (2) miRNA profiles are associated with and may predict platelet reactivity, and (3) bioinformatic approaches can successfully identify functional miRNAs in platelets.
Collapse
|
46
|
Expression of Gαz in C2C12 cells restrains myogenic differentiation. Cell Signal 2011; 23:389-97. [DOI: 10.1016/j.cellsig.2010.10.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 09/16/2010] [Accepted: 10/01/2010] [Indexed: 10/19/2022]
|
47
|
Abstract
Upon vascular injury, platelets are activated by adhesion to adhesive proteins, such as von Willebrand factor and collagen, or by soluble platelet agonists, such as ADP, thrombin, and thromboxane A(2). These adhesive proteins and soluble agonists induce signal transduction via their respective receptors. The various receptor-specific platelet activation signaling pathways converge into common signaling events that stimulate platelet shape change and granule secretion and ultimately induce the "inside-out" signaling process leading to activation of the ligand-binding function of integrin α(IIb)β(3). Ligand binding to integrin α(IIb)β(3) mediates platelet adhesion and aggregation and triggers "outside-in" signaling, resulting in platelet spreading, additional granule secretion, stabilization of platelet adhesion and aggregation, and clot retraction. It has become increasingly evident that agonist-induced platelet activation signals also cross talk with integrin outside-in signals to regulate platelet responses. Platelet activation involves a series of rapid positive feedback loops that greatly amplify initial activation signals and enable robust platelet recruitment and thrombus stabilization. Recent studies have provided novel insight into the molecular mechanisms of these processes.
Collapse
Affiliation(s)
- Zhenyu Li
- Department of Medicine, University of Kentucky
| | | | | | - Xiaoping Du
- Department of Pharmacology, University of Illinois at Chicago
| |
Collapse
|
48
|
Platelet receptor signaling in thrombus formation. J Mol Med (Berl) 2010; 89:109-21. [DOI: 10.1007/s00109-010-0691-5] [Citation(s) in RCA: 144] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 09/27/2010] [Accepted: 10/08/2010] [Indexed: 01/09/2023]
|
49
|
Nash CA, Séverin S, Dawood BB, Makris M, Mumford A, Wilde J, Senis YA, Watson SP. Src family kinases are essential for primary aggregation by G(i) -coupled receptors. J Thromb Haemost 2010; 8:2273-82. [PMID: 20738760 DOI: 10.1111/j.1538-7836.2010.03992.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
INTRODUCTION AND BACKGROUND Adrenaline stimulates biphasic aggregation in plasma through the G(i) -coupled α(2A) -adrenoreceptor. In the present study, we demonstrate that both primary and secondary wave aggregation induced by adrenaline in plasma is blocked by two structurally distinct inhibitors of Src family kinases, dasatinib and PD0173952. METHODS AND RESULTS In contrast, primary aggregation is partially inhibited or unaffected in the presence of inhibitors of cyclo-oxygenase, phosphoinositide (PI) 3-kinases, and P2Y(1) and P2Y(12) ADP receptors, although secondary aggregation is abolished. The ability of adrenaline to inhibit adenylyl cyclase and to synergize with platelet agonists in mediating platelet activation in plasma is retained in the presence of Src family kinase inhibition. Moreover, adrenaline does not activate Src family kinases, as determined by western blotting of their regulatory tyrosines, suggesting that constitutive signaling from Src family kinases may underlie their role in activation. Adrenaline is widely used in clinical laboratories for investigation of patients with suspected bleeding disorders. In a group of 90 unrelated patients with a clinically diagnosed platelet bleeding disorder, we identified four who did not exhibit primary wave aggregation in response to adrenaline, although the catecholamine potentiated the response to other agonists, and five who failed to undergo secondary wave aggregation. In contrast, adrenaline stimulated biphasic aggregation in 60 controls. All of the patients with a defective response to adrenaline had impaired ADP-induced platelet activation. CONCLUSIONS The present results indicate a previously unappreciated role for Src family kinases in mediating G(i) signaling in plasma, and demonstrate heterogeneity in response to adrenaline in patients with a clinically diagnosed platelet disorder.
Collapse
Affiliation(s)
- C A Nash
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, UK.
| | | | | | | | | | | | | | | |
Collapse
|
50
|
|