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Wu Y, Jensen N, Rossner MJ, Wehr MC. Exploiting Cell-Based Assays to Accelerate Drug Development for G Protein-Coupled Receptors. Int J Mol Sci 2024; 25:5474. [PMID: 38791511 PMCID: PMC11121687 DOI: 10.3390/ijms25105474] [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: 04/22/2024] [Revised: 05/10/2024] [Accepted: 05/13/2024] [Indexed: 05/26/2024] Open
Abstract
G protein-coupled receptors (GPCRs) are relevant targets for health and disease as they regulate various aspects of metabolism, proliferation, differentiation, and immune pathways. They are implicated in several disease areas, including cancer, diabetes, cardiovascular diseases, and mental disorders. It is worth noting that about a third of all marketed drugs target GPCRs, making them prime pharmacological targets for drug discovery. Numerous functional assays have been developed to assess GPCR activity and GPCR signaling in living cells. Here, we review the current literature of genetically encoded cell-based assays to measure GPCR activation and downstream signaling at different hierarchical levels of signaling, from the receptor to transcription, via transducers, effectors, and second messengers. Singleplex assay formats provide one data point per experimental condition. Typical examples are bioluminescence resonance energy transfer (BRET) assays and protease cleavage assays (e.g., Tango or split TEV). By contrast, multiplex assay formats allow for the parallel measurement of multiple receptors and pathways and typically use molecular barcodes as transcriptional reporters in barcoded assays. This enables the efficient identification of desired on-target and on-pathway effects as well as detrimental off-target and off-pathway effects. Multiplex assays are anticipated to accelerate drug discovery for GPCRs as they provide a comprehensive and broad identification of compound effects.
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Affiliation(s)
- Yuxin Wu
- Research Group Cell Signalling, Department of Psychiatry and Psychotherapy, LMU University Hospital, LMU Munich, Nussbaumstr. 7, 80336 Munich, Germany
- Systasy Bioscience GmbH, Balanstr. 6, 81669 Munich, Germany
| | - Niels Jensen
- Systasy Bioscience GmbH, Balanstr. 6, 81669 Munich, Germany
- Section of Molecular Neurobiology, Department of Psychiatry and Psychotherapy, LMU University Hospital, LMU Munich, Nussbaumstr. 7, 80336 Munich, Germany
| | - Moritz J. Rossner
- Systasy Bioscience GmbH, Balanstr. 6, 81669 Munich, Germany
- Section of Molecular Neurobiology, Department of Psychiatry and Psychotherapy, LMU University Hospital, LMU Munich, Nussbaumstr. 7, 80336 Munich, Germany
| | - Michael C. Wehr
- Research Group Cell Signalling, Department of Psychiatry and Psychotherapy, LMU University Hospital, LMU Munich, Nussbaumstr. 7, 80336 Munich, Germany
- Systasy Bioscience GmbH, Balanstr. 6, 81669 Munich, Germany
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2
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Maggio R, Fasciani I, Petragnano F, Coppolino MF, Scarselli M, Rossi M. Unraveling the Functional Significance of Unstructured Regions in G Protein-Coupled Receptors. Biomolecules 2023; 13:1431. [PMID: 37892113 PMCID: PMC10604838 DOI: 10.3390/biom13101431] [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: 08/30/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/29/2023] Open
Abstract
Unstructured regions in functional proteins have gained attention in recent years due to advancements in informatics tools and biophysical methods. G protein-coupled receptors (GPCRs), a large family of cell surface receptors, contain unstructured regions in the form of the i3 loop and C-terminus. This review provides an overview of the functional significance of these regions in GPCRs. GPCRs transmit signals from the extracellular environment to the cell interior, regulating various physiological processes. The i3 loop, located between the fifth and sixth transmembrane helices, and the C-terminus, connected to the seventh transmembrane helix, are determinant of interactions with G proteins and with other intracellular partners such as arrestins. Recent studies demonstrate that the i3 loop and C-terminus play critical roles in allosterically regulating GPCR activation. They can act as autoregulators, adopting conformations that, by restricting G protein access, modulate receptor coupling specificity. The length and unstructured nature of the i3 loop and C-terminus provide unique advantages in GPCR interactions with intracellular protein partners. They act as "fishing lines", expanding the radius of interaction and enabling GPCRs to tether scaffolding proteins, thus facilitating receptor stability during cell membrane movements. Additionally, the i3 loop may be involved in domain swapping between GPCRs, generating novel receptor dimers with distinct binding and coupling characteristics. Overall, the i3 loop and C-terminus are now widely recognized as crucial elements in GPCR function and regulation. Understanding their functional roles enhances our comprehension of GPCR structure and signaling complexity and holds promise for advancements in receptor pharmacology and drug development.
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Affiliation(s)
- Roberto Maggio
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy; (I.F.); (F.P.); (M.R.)
| | - Irene Fasciani
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy; (I.F.); (F.P.); (M.R.)
| | - Francesco Petragnano
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy; (I.F.); (F.P.); (M.R.)
| | - Maria Francesca Coppolino
- Department of Life, Health and Environmental Sciences, University of L’Aquila, 67100 L’Aquila, Italy;
| | - Marco Scarselli
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy;
| | - Mario Rossi
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy; (I.F.); (F.P.); (M.R.)
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3
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Chandrabalan A, Firth A, Litchfield RB, Appleton CT, Getgood A, Ramachandran R. Human osteoarthritis knee joint synovial fluids cleave and activate Proteinase-Activated Receptor (PAR) mediated signaling. Sci Rep 2023; 13:1124. [PMID: 36670151 PMCID: PMC9859807 DOI: 10.1038/s41598-023-28068-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 01/12/2023] [Indexed: 01/22/2023] Open
Abstract
Osteoarthritis (OA) is the most prevalent joint disorder with increasing worldwide incidence. Mechanistic insights into OA pathophysiology are evolving and there are currently no disease-modifying OA drugs. An increase in protease activity is linked to progressive degradation of the cartilage in OA. Proteases also trigger inflammation through a family of G protein-coupled receptors (GPCRs) called the Proteinase-Activated Receptors (PARs). PAR signaling can trigger pro-inflammatory responses and targeting PARs is proposed as a therapeutic approach in OA. Several enzymes can cleave the PAR N-terminus, but the endogenous protease activators of PARs in OA remain unclear. Here we characterized PAR activating enzymes in knee joint synovial fluids from OA patients and healthy donors using genetically encoded PAR biosensor expressing cells. Calcium signaling assays were performed to examine receptor activation. The class and type of enzymes cleaving the PARs was further characterized using protease inhibitors and fluorogenic substrates. We find that PAR1, PAR2 and PAR4 activating enzymes are present in knee joint synovial fluids from healthy controls and OA patients. Compared to healthy controls, PAR1 activating enzymes are elevated in OA synovial fluids while PAR4 activating enzyme levels are decreased. Using enzyme class and type selective inhibitors and fluorogenic substrates we find that multiple PAR activating enzymes are present in OA joint fluids and identify serine proteinases (thrombin and trypsin-like) and matrix metalloproteinases as the major classes of PAR activating enzymes in the OA synovial fluids. Synovial fluid driven increase in calcium signaling was significantly reduced in cells treated with PAR1 and PAR2 antagonists, but not in PAR4 antagonist treated cells. OA associated elevation of PAR1 cleavage suggests that targeting this receptor may be beneficial in the treatment of OA.
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Affiliation(s)
- Arundhasa Chandrabalan
- Department of Physiology and Pharmacology, Bone and Joint Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - Andrew Firth
- Division of Orthopedic Surgery, Bone and Joint Institute, Fowler Kennedy Sport Medicine Clinic, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Robert B Litchfield
- Division of Orthopedic Surgery, Bone and Joint Institute, Fowler Kennedy Sport Medicine Clinic, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - C Thomas Appleton
- Department of Physiology and Pharmacology, Bone and Joint Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5C1, Canada.,Department of Medicine, Bone and Joint Institute, Schulich School of Medicine and Dentistry, The Dr. Sandy Kirkley Centre for Musculoskeletal Research, London, ON, Canada
| | - Alan Getgood
- Division of Orthopedic Surgery, Bone and Joint Institute, Fowler Kennedy Sport Medicine Clinic, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Rithwik Ramachandran
- Department of Physiology and Pharmacology, Bone and Joint Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5C1, Canada.
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Peach CJ, Edgington-Mitchell LE, Bunnett NW, Schmidt BL. Protease-activated receptors in health and disease. Physiol Rev 2023; 103:717-785. [PMID: 35901239 PMCID: PMC9662810 DOI: 10.1152/physrev.00044.2021] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 07/08/2022] [Accepted: 07/10/2022] [Indexed: 11/22/2022] Open
Abstract
Proteases are signaling molecules that specifically control cellular functions by cleaving protease-activated receptors (PARs). The four known PARs are members of the large family of G protein-coupled receptors. These transmembrane receptors control most physiological and pathological processes and are the target of a large proportion of therapeutic drugs. Signaling proteases include enzymes from the circulation; from immune, inflammatory epithelial, and cancer cells; as well as from commensal and pathogenic bacteria. Advances in our understanding of the structure and function of PARs provide insights into how diverse proteases activate these receptors to regulate physiological and pathological processes in most tissues and organ systems. The realization that proteases and PARs are key mediators of disease, coupled with advances in understanding the atomic level structure of PARs and their mechanisms of signaling in subcellular microdomains, has spurred the development of antagonists, some of which have advanced to the clinic. Herein we review the discovery, structure, and function of this receptor system, highlight the contribution of PARs to homeostatic control, and discuss the potential of PAR antagonists for the treatment of major diseases.
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Affiliation(s)
- Chloe J Peach
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, New York
- Department of Neuroscience and Physiology and Neuroscience Institute, Grossman School of Medicine, New York University, New York, New York
| | - Laura E Edgington-Mitchell
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
- Bluestone Center for Clinical Research, Department of Oral and Maxillofacial Surgery, New York University College of Dentistry, New York, New York
| | - Nigel W Bunnett
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, New York
- Department of Neuroscience and Physiology and Neuroscience Institute, Grossman School of Medicine, New York University, New York, New York
| | - Brian L Schmidt
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, New York
- Bluestone Center for Clinical Research, Department of Oral and Maxillofacial Surgery, New York University College of Dentistry, New York, New York
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Renna SA, Michael JV, Kong X, Ma L, Ma P, Nieman MT, Edelstein LC, McKenzie SE. Human and mouse PAR4 are functionally distinct receptors: Studies in novel humanized mice. J Thromb Haemost 2022; 20:1236-1247. [PMID: 35152546 DOI: 10.1111/jth.15669] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 08/31/2023]
Abstract
BACKGROUND Human and mouse platelets both express protease-activated receptor (PAR) 4 but sequence alignment reveals differences in several functional domains. These differences may result in functional disparities between the receptors which make it difficult to translate PAR4 studies using mice to human platelet physiology. OBJECTIVES To generate transgenic mice that express human, but not mouse, PAR4 and directly compare human and mouse PAR4 function in the same platelet environment. METHODS Transgenic mice were made using a genomic clone of the F2RL3 gene (encoding PAR4) and backcrossed with Par4 KO mice. For certain experiments, mice were bred with GRK6 KO mice. Tail bleeding time and platelet function in response to PAR4-activating peptide were assessed. RESULTS Human F2RL3 was successfully integrated into the mouse genome, transgenic mice were crossed to the mPar4 KO background (PAR4 tg/KO), and PAR4 was functionally expressed on platelets. Compared to WT, PAR4 tg/KO mice exhibited shortened tail bleeding time and their platelets were more responsive to PAR4-AP as assessed by α-granule release and integrin activation. The opposite was observed with thrombin. Knocking out GRK6 had no effect on human PAR4-expressing platelets, unlike mouse Par4-expressing platelets. PAR4 tg/KO platelets exhibited greater Ca2+ area under the curve and more robust extracellular vesicle release than WT stimulated with PAR4-AP. CONCLUSION These data suggest that (1) human PAR4- and mouse Par4-mediated signaling are different and (2) the feedback regulation mechanisms of human and mouse PAR4 are different. These functional differences are important to consider when interpreting PAR4 studies done with mice.
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Affiliation(s)
- Stephanie A Renna
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - James V Michael
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Xianguo Kong
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Lin Ma
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Peisong Ma
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Marvin T Nieman
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Leonard C Edelstein
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Steven E McKenzie
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
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Chandrabalan A, Ramachandran R. Molecular mechanisms regulating Proteinase‐Activated Receptors (PARs). FEBS J 2021; 288:2697-2726. [DOI: 10.1111/febs.15829] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/10/2021] [Accepted: 03/18/2021] [Indexed: 12/13/2022]
Affiliation(s)
- Arundhasa Chandrabalan
- Department of Physiology and Pharmacology Schulich School of Medicine and Dentistry University of Western Ontario London Canada
| | - Rithwik Ramachandran
- Department of Physiology and Pharmacology Schulich School of Medicine and Dentistry University of Western Ontario London Canada
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Avet C, Sturino C, Grastilleur S, Gouill CL, Semache M, Gross F, Gendron L, Bennani Y, Mancini JA, Sayegh CE, Bouvier M. The PAR2 inhibitor I-287 selectively targets Gα q and Gα 12/13 signaling and has anti-inflammatory effects. Commun Biol 2020; 3:719. [PMID: 33247181 PMCID: PMC7695697 DOI: 10.1038/s42003-020-01453-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/29/2020] [Indexed: 01/01/2023] Open
Abstract
Protease-activated receptor-2 (PAR2) is involved in inflammatory responses and pain, therefore representing a promising therapeutic target for the treatment of immune-mediated inflammatory diseases. However, as for other GPCRs, PAR2 can activate multiple signaling pathways and those involved in inflammatory responses remain poorly defined. Here, we describe a new selective and potent PAR2 inhibitor (I-287) that shows functional selectivity by acting as a negative allosteric regulator on Gαq and Gα12/13 activity and their downstream effectors, while having no effect on Gi/o signaling and βarrestin2 engagement. Such selective inhibition of only a subset of the pathways engaged by PAR2 was found to be sufficient to block inflammation in vivo. In addition to unraveling the PAR2 signaling pathways involved in the pro-inflammatory response, our study opens the path toward the development of new functionally selective drugs with reduced liabilities that could arise from blocking all the signaling activities controlled by the receptor. Avet et al. characterize I-287, an inhibitor to protease-activated receptor 2 using BRET-assays. They find that I-287 selectively inhibits Gαq and Gα12/13 without affecting the activation of Gi/o or the recruitment of βarrestin2 and that it blocks inflammation in vitro and in vivo.
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Affiliation(s)
- Charlotte Avet
- Institute for Research in Immunology and Cancer, and Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada, H3C 1J4
| | - Claudio Sturino
- Vertex Pharmaceuticals (Canada), Inc., Laval, QC, Canada, H7V 4A7.,Paraza Pharma, Inc., Saint-Laurent, QC, Canada, H4S 2E1
| | - Sébastien Grastilleur
- Département de Pharmacologie-Physiologie, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'Excellence en Neurosciences de l'Université de Sherbrooke, Institut de Pharmacologie de Sherbrooke, Sherbrooke, QC, Canada, J1H 5N4
| | - Christian Le Gouill
- Institute for Research in Immunology and Cancer, and Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada, H3C 1J4
| | - Meriem Semache
- Institute for Research in Immunology and Cancer, and Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada, H3C 1J4.,Domain Therapeutics North America, Saint-Laurent, QC, Canada, H4S 1Z9
| | - Florence Gross
- Institute for Research in Immunology and Cancer, and Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada, H3C 1J4.,Domain Therapeutics North America, Saint-Laurent, QC, Canada, H4S 1Z9
| | - Louis Gendron
- Département de Pharmacologie-Physiologie, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'Excellence en Neurosciences de l'Université de Sherbrooke, Institut de Pharmacologie de Sherbrooke, Sherbrooke, QC, Canada, J1H 5N4
| | - Youssef Bennani
- Vertex Pharmaceuticals (Canada), Inc., Laval, QC, Canada, H7V 4A7.,AdMare BioInnovations, Saint-Laurent, QC, Canada, H4S 1Z9
| | - Joseph A Mancini
- Vertex Pharmaceuticals (Canada), Inc., Laval, QC, Canada, H7V 4A7.,Vertex Pharmaceuticals Inc., Boston, MA, 02210, USA
| | - Camil E Sayegh
- Vertex Pharmaceuticals (Canada), Inc., Laval, QC, Canada, H7V 4A7.,Ra Pharmaceuticals, Inc., Cambridge, MA, 02140, USA
| | - Michel Bouvier
- Institute for Research in Immunology and Cancer, and Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada, H3C 1J4.
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