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Erreger K, Cao S, Pan Y, Jiang M, Zhang MZ, Harris RC, Hamm HE. Role of protease-activated receptor 4 in mouse models of acute and chronic kidney injury. Am J Physiol Renal Physiol 2024; 326:F219-F226. [PMID: 38031732 PMCID: PMC11198992 DOI: 10.1152/ajprenal.00162.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 11/22/2023] [Accepted: 11/22/2023] [Indexed: 12/01/2023] Open
Abstract
Protease-activated receptor 4 (PAR4) is a G protein-coupled receptor activated by thrombin. In the platelet, response to thrombin PAR4 contributes to the predominant procoagulant microparticle formation, increased fibrin deposition, and initiation of platelet-stimulated inflammation. In addition, PAR4 is expressed in other cell types, including endothelial cells. Under inflammatory conditions, PAR4 is overexpressed via epigenetic demethylation of the PAR4 gene, F2RL3. PAR4 knockout (KO) studies have determined a role for PAR4 in ischemia-reperfusion injury in the brain, and PAR4 KO mice display normal cardiac function but present less myocyte death and cardiac dysfunction in response to acute myocardial infarction. Although PAR4 has been reported to be expressed within the kidney, the contribution of PAR4 to acute kidney injury (AKI) and chronic kidney disease (CKD) is not well understood. Here we report that PAR4 KO mice are protected against kidney injury in two mouse models. First, PAR4 KO mice are protected against induction of markers of both fibrosis and inflammation in two different models of kidney injury: 1) 7 days following unilateral ureter obstruction (UUO) and 2) an AKI-CKD model of ischemia-reperfusion followed by 8 days of contralateral nephrectomy. We further show that PAR4 expression in the kidney is low in the control mouse kidney but induced over time following UUO. PAR4 KO mice are protected against blood urea nitrogen (BUN) and glomerular filtration rate (GFR) kidney function pathologies in the AKI-CKD model. Following the AKI-CKD model, PAR4 is expressed in the collecting duct colocalizing with Dolichos biflorus agglutinin (DBA), but not in the proximal tubule with Lotus tetragonolobus lectin (LTL). Collectively, the results reported in this study implicate PAR4 as contributing to the pathology in mouse models of acute and chronic kidney injury.NEW & NOTEWORTHY The contribution of the thrombin receptor protease-activated receptor 4 (PAR4) to acute kidney injury (AKI) and chronic kidney disease (CKD) is not well understood. Here we report that PAR4 expression is upregulated after kidney injury and PAR4 knockout (KO) mice are protected against fibrosis following kidney injury in two mouse models. First, PAR4 KO mice are protected against unilateral ureter obstruction. Second, PAR4 KO mice are protected against an AKI-CKD model of ischemia-reperfusion followed by contralateral nephrectomy.
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Affiliation(s)
- Kevin Erreger
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Shirong Cao
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Yu Pan
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Mengdi Jiang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Ming-Zhi Zhang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Raymond C Harris
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Heidi E Hamm
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
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Alejandra WP, Miriam Irene JP, Fabio Antonio GS, Patricia RGR, Elizabeth TA, Juan Pablo AA, Rebeca GV. Production of monoclonal antibodies for therapeutic purposes: A review. Int Immunopharmacol 2023; 120:110376. [PMID: 37244118 DOI: 10.1016/j.intimp.2023.110376] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/02/2023] [Accepted: 05/19/2023] [Indexed: 05/29/2023]
Abstract
Monoclonal antibodies (mAbs) have been used in the development of immunotherapies that target a variety of diseases, such as cancer, autoimmune diseases, and even viral infections; they play a key role in immunization and are expected after vaccination. However, some conditions do not promote the development of neutralizing antibodies. Production and use of mAbs, generated in biofactories, represent vast potential as aids in immunological responses when the organism cannot produce them on their own, these convey unique specificity by recognizing and targeting specific antigen. Antibodies can be defined as heterotetrametric glycoproteins of symmetric nature, and they participate as effector proteins in humoral responses. Additionally, there are different types of mAbs (murine, chimeric, humanized, human, mAbs as Antibody-drug conjugates and bispecific mAbs) discussed in the present work. When these molecules are produced in vitro as mAbs, several common techniques, such as hybridomas or phage display are used. There are several preferred cell lines that function as biofactories, for the production of mAbs, the selection of which rely on the variation of adaptability, productivity and both phenotypic and genotypic shifts. After the cell expression systems and culture techniques are used, there are diverse specialized downstream processes to achieve desired yield and isolation as well as product quality and characterization. Novel perspectives regarding these protocols represent a potential improvement for mAbs high-scale production.
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Affiliation(s)
- Waller-Pulido Alejandra
- Tecnologico de Monterrey, School of Engineering and Science, Ave. General Ramon Corona 2514, 45138 Zapopan, Jalisco, Mexico
| | - Jiménez-Pérez Miriam Irene
- Tecnologico de Monterrey, School of Medicine and Health Science, Ave. General Ramon Corona 2514, 45138 Zapopan, Jalisco, Mexico
| | - Gonzalez-Sanchez Fabio Antonio
- Tecnologico de Monterrey, School of Engineering and Science, Ave. General Ramon Corona 2514, 45138 Zapopan, Jalisco, Mexico
| | | | | | - Aleman-Aguilar Juan Pablo
- Tecnologico de Monterrey, School of Medicine and Health Science, Ave. General Ramon Corona 2514, 45138 Zapopan, Jalisco, Mexico.
| | - Garcia-Varela Rebeca
- Tecnologico de Monterrey, School of Engineering and Science, Ave. General Ramon Corona 2514, 45138 Zapopan, Jalisco, Mexico.
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Gnanenthiran SR, Pennings GJ, Reddel CJ, Campbell H, Kockx M, Hamilton JR, Chen V, Kritharides L. Identification of a Distinct Platelet Phenotype in the Elderly: ADP Hypersensitivity Coexists With Platelet PAR (Protease-Activated Receptor)-1 and PAR-4-Mediated Thrombin Resistance. Arterioscler Thromb Vasc Biol 2022; 42:960-972. [PMID: 35708029 DOI: 10.1161/atvbaha.120.316772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Thrombin (via PAR [protease-activated receptor]-1 and PAR-4) and ADP (via P2Y12 receptors) are potent endogenous platelet activators implicated in the development of cardiovascular disease. We aimed to assess whether platelet pathways alter with aging. METHODS We characterized platelet activity in community-dwelling volunteers (n=174) in the following age groups: (1) 20 to 30 (young); (2) 40 to 55 (middle-aged); (3) ≥70 years (elderly). Platelet activity was assessed by aggregometry; flow cytometry (surface markers [P-selectin: alpha granule release, CD63: dense granule release, PAC-1 (measure of conformationally active GPIIb/IIIa at the fibrinogen binding site): GPIIb/IIIa conformational activation] measured under basal conditions and after agonist stimulation [ADP, thrombin, PAR-1 agonist or PAR-4 agonist]); receptor cleavage and quantification; fluorometry; calcium flux; ELISA. RESULTS The elderly had higher basal platelet activation than the young, evidenced by increased expression of P-selectin, CD63, and PAC-1, which correlated with increasing inflammation (IL [interleukin]-1β/IL-6). The elderly demonstrated higher P2Y12 receptor density, with greater ADP-induced platelet aggregation (P<0.05). However, elderly subjects were resistant to thrombin, achieving less activation in response to thrombin (higher EC50) and to selective stimulation of both PAR-1 and PAR-4, with higher basal PAR-1/PAR-4 cleavage and less inducible PAR-1/PAR-4 cleavage (all P<0.05). Thrombin resistance was attributable to a combination of reduced thrombin orienting receptor GPIbα, reduced secondary ADP contribution to thrombin-mediated activation, and blunted calcium flux. D-Dimer, a marker of in situ thrombin generation, correlated with platelet activation in the circulation, ex vivo thrombin resistance, and circulating inflammatory mediators (TNF [tumor necrosis factor]-α/IL-6). CONCLUSIONS Aging is associated with a distinctive platelet phenotype of increased basal activation, ADP hyperreactivity, and thrombin resistance. In situ thrombin generation associated with systemic inflammation may be novel target to prevent cardiovascular disease in the elderly.
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Affiliation(s)
- Sonali R Gnanenthiran
- Cardiology Department, Concord Repatriation General Hospital, NSW, Australia (S.R.G., M.K., L.K.).,ANZAC Research Institute, Concord Repatriation General Hospital, and University of Sydney, Sydney, NSW, Australia (S.R.G., G.J.P., C.J.R., H.C., M.K., V.C., L.K.)
| | - Gabrielle J Pennings
- ANZAC Research Institute, Concord Repatriation General Hospital, and University of Sydney, Sydney, NSW, Australia (S.R.G., G.J.P., C.J.R., H.C., M.K., V.C., L.K.)
| | - Caroline J Reddel
- ANZAC Research Institute, Concord Repatriation General Hospital, and University of Sydney, Sydney, NSW, Australia (S.R.G., G.J.P., C.J.R., H.C., M.K., V.C., L.K.)
| | - Heather Campbell
- ANZAC Research Institute, Concord Repatriation General Hospital, and University of Sydney, Sydney, NSW, Australia (S.R.G., G.J.P., C.J.R., H.C., M.K., V.C., L.K.)
| | - Maaike Kockx
- Cardiology Department, Concord Repatriation General Hospital, NSW, Australia (S.R.G., M.K., L.K.).,ANZAC Research Institute, Concord Repatriation General Hospital, and University of Sydney, Sydney, NSW, Australia (S.R.G., G.J.P., C.J.R., H.C., M.K., V.C., L.K.)
| | - Justin R Hamilton
- Australian Centre of Blood Diseases, Monash University, Victoria, Australia (J.R.H.)
| | - Vivien Chen
- ANZAC Research Institute, Concord Repatriation General Hospital, and University of Sydney, Sydney, NSW, Australia (S.R.G., G.J.P., C.J.R., H.C., M.K., V.C., L.K.).,Haematology Department, Concord Repatriation General Hospital, NSW, Australia (V.C.)
| | - Leonard Kritharides
- Cardiology Department, Concord Repatriation General Hospital, NSW, Australia (S.R.G., M.K., L.K.).,ANZAC Research Institute, Concord Repatriation General Hospital, and University of Sydney, Sydney, NSW, Australia (S.R.G., G.J.P., C.J.R., H.C., M.K., V.C., L.K.)
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Yu X, Li S, Zhu X, Kong Y. Inhibitors of protease activated receptor 4 (PAR4): a review of recent patents (2013-2021). Expert Opin Ther Pat 2022; 32:153-170. [PMID: 35081321 DOI: 10.1080/13543776.2022.2034786] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Protease-activated receptor 4 (PAR4), belonging to a subfamily of G-protein-coupled receptors (GPCR), is expressed on the surface of Human platelets, and the activation of it can lead to platelets aggregation. Studies demonstrated that PAR4 inhibition protect mice from arterial/arteriolar thrombosis, pulmonary embolism and cerebral infarct, while do not affect the haemostatic responses integrity. Therefore, PAR4 has been a promising target for the development of anti-thrombotic agents. AREAS COVERED This review covers recent patents and literature on PAR4 and their application published between 2013 and 2021. EXPERT OPINION PAR4 is a promising anti-thrombotic target and PAR4 inhibitors are important biologically active compounds for the treatment of thrombosis. Most the recent patents and literature focus on PAR4 selective inhibitors, and BMS-986120 and BMS-986141, which were developed by BMS, have entered clinical trials. With the deep understanding of the crystal structures and biological functions of PAR4, we believe that many other novel types of molecules targeting PAR4 would enter the clinical studies or the market.
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Affiliation(s)
- Xiangying Yu
- School of Life & Technology, China Pharmaceutical University, Nanjing, 210009, PR China
| | - Shanshan Li
- Institute of Medicinal & Chemistry, China Pharmaceutical University, Nanjing, 210009, PR China
| | - Xiong Zhu
- Institute of Medicinal & Chemistry, China Pharmaceutical University, Nanjing, 210009, PR China
| | - Yi Kong
- School of Life & Technology, China Pharmaceutical University, Nanjing, 210009, PR China
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Scott MJ, Jowett A, Orecchia M, Ertl P, Ouro-Gnao L, Ticehurst J, Gower D, Yates J, Poulton K, Harris C, Mullin MJ, Smith KJ, Lewis AP, Barton N, Washburn ML, de Wildt R. Rapid identification of highly potent human anti-GPCR antagonist monoclonal antibodies. MAbs 2021; 12:1755069. [PMID: 32343620 PMCID: PMC7188403 DOI: 10.1080/19420862.2020.1755069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Complex cellular targets such as G protein-coupled receptors (GPCRs), ion channels, and other multi-transmembrane proteins represent a significant challenge for therapeutic antibody discovery, primarily because of poor stability of the target protein upon extraction from cell membranes. To assess whether a limited set of membrane-bound antigen formats could be exploited to identify functional antibodies directed against such targets, we selected a GPCR of therapeutic relevance (CCR1) and identified target binders using an in vitro yeast-based antibody discovery platform (AdimabTM) to expedite hit identification. Initially, we compared two different biotinylated antigen formats overexpressing human CCR1 in a ‘scouting’ approach using a subset of the antibody library. Binders were isolated using streptavidin-coated beads, expressed as yeast supernatants, and screened using a high-throughput binding assay and flow cytometry on appropriate cell lines. The most suitable antigen was then selected to isolate target binders using the full library diversity. This approach identified a combined total of 183 mAbs with diverse heavy chain sequences. A subset of clones exhibited high potencies in primary cell chemotaxis assays, with IC50 values in the low nM/high pM range. To assess the feasibility of any further affinity enhancement, full-length hCCR1 protein was purified, complementary-determining region diversified libraries were constructed from a high and lower affinity mAb, and improved binders were isolated by fluorescence-activated cell sorting selections. A significant affinity enhancement was observed for the lower affinity parental mAb, but not the high affinity mAb. These data exemplify a methodology to generate potent human mAbs for challenging targets rapidly using whole cells as antigen and define a route to the identification of affinity-matured variants if required.
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Affiliation(s)
- Martin J Scott
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Amanda Jowett
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Martin Orecchia
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Peter Ertl
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Larissa Ouro-Gnao
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Julia Ticehurst
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - David Gower
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - John Yates
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Katie Poulton
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Carol Harris
- Department of Protein & Cellular Sciences, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Michael J Mullin
- Department of Protein & Cellular Sciences, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Kathrine J Smith
- Department of Protein & Cellular Sciences, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Alan P Lewis
- Department of Data & Computational Sciences, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Nick Barton
- Department of Data & Computational Sciences, Glaxo Smith Kline Research & Development, Hertfordshire, UK
| | - Michael L Washburn
- Experimental Medicine Unit, Glaxo Smith Kline Research & Development, Collegeville, PA, USA
| | - Ruud de Wildt
- Department of Biopharm Discovery, Glaxo Smith Kline Research & Development, Hertfordshire, UK
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6
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de la Fuente M, Han X, Miyagi M, Nieman MT. Expression and Purification of Protease-Activated Receptor 4 (PAR4) and Analysis with Histidine Hydrogen-Deuterium Exchange. Biochemistry 2020; 59:671-681. [PMID: 31957446 DOI: 10.1021/acs.biochem.9b00987] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Protease-activated receptors (PARs) are G-protein-coupled receptors that are activated by proteolysis of the N-terminus, which exposes a tethered ligand that interacts with the receptor. Numerous studies have focused on the signaling pathways mediated by PARs. However, the structural basis for initiation of these pathways is unknown. Here, we describe a strategy for the expression and purification of PAR4. This is the first PAR family member to be isolated without stabilizing modifications for biophysical studies. We monitored PAR4 activation with histidine hydrogen-deuterium exchange. PAR4 has nine histidines that are spaced throughout the protein, allowing a global view of solvent accessible and nonaccessible regions. Peptides containing each of the nine His residues were used to determine the t1/2 for each His residue in apo or thrombin-activated PAR4. The thrombin-cleaved PAR4 exhibited a 2-fold increase (p > 0.01) in t1/2 values observed for four histidine residues (His180, His229, His240, and His380), demonstrating that these regions have decreased solvent accessibility upon thrombin treatment. In agreement, thrombin-cleaved PAR4 also was resistant to thermolysin digestion. In contrast, the rate of thermolysin proteolysis following stimulation with the PAR4 activation peptide was the same as that of unstimulated PAR4. Further analysis showed the C-terminus is protected in thrombin-activated PAR4 compared to uncleaved or agonist peptide-treated PAR4. The studies described here are the first to examine the tethered ligand activation mechanism for a PAR family member biophysically and shed light on the overall conformational changes that follow activation of PARs by a protease.
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Affiliation(s)
- Maria de la Fuente
- Department of Pharmacology , Case Western Reserve University , Cleveland , Ohio 44106-4965 , United States
| | - Xu Han
- Department of Pharmacology , Case Western Reserve University , Cleveland , Ohio 44106-4965 , United States
| | - Masaru Miyagi
- Department of Pharmacology , Case Western Reserve University , Cleveland , Ohio 44106-4965 , United States
| | - Marvin T Nieman
- Department of Pharmacology , Case Western Reserve University , Cleveland , Ohio 44106-4965 , United States
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7
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Ma Y, Ding Y, Song X, Ma X, Li X, Zhang N, Song Y, Sun Y, Shen Y, Zhong W, Hu LA, Ma Y, Zhang MY. Structure-guided discovery of a single-domain antibody agonist against human apelin receptor. SCIENCE ADVANCES 2020; 6:eaax7379. [PMID: 31998837 PMCID: PMC6962038 DOI: 10.1126/sciadv.aax7379] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 10/29/2019] [Indexed: 06/01/2023]
Abstract
Developing antibody agonists targeting the human apelin receptor (APJ) is a promising therapeutic approach for the treatment of chronic heart failure. Here, we report the structure-guided discovery of a single-domain antibody (sdAb) agonist JN241-9, based on the cocrystal structure of APJ with an sdAb antagonist JN241, the first cocrystal structure of a class A G protein-coupled receptor (GPCR) with a functional antibody. As revealed by the structure, JN241 binds to the extracellular side of APJ, makes critical contacts with the second extracellular loop, and inserts the CDR3 into the ligand-binding pocket. We converted JN241 into a full agonist JN241-9 by inserting a tyrosine into the CDR3. Modeling and molecular dynamics simulation shed light on JN241-9-stimulated receptor activation, providing structural insights for finding agonistic antibodies against class A GPCRs.
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Affiliation(s)
- Yanbin Ma
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Yao Ding
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Xianqiang Song
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Xiaochuan Ma
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Xun Li
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Ning Zhang
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Yunpeng Song
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Yaping Sun
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Yuqing Shen
- Therapeutic Discovery, Amgen Inc., One Amgen Center Dr., Thousand Oaks, CA 91320, USA
| | - Wenge Zhong
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Liaoyuan A. Hu
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Yingli Ma
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
| | - Mei-Yun Zhang
- Amgen Discovery Research, Amgen Asia R&D Center, Amgen Biopharmaceutical R&D (Shanghai) Co. Ltd., 13th Floor, Building No. 2, 4560 Jinke Road, Zhangjiang, Shanghai 201210, China
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8
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Therapeutic Monoclonal Antibodies to Complex Membrane Protein Targets: Antigen Generation and Antibody Discovery Strategies. BioDrugs 2019; 32:339-355. [PMID: 29934752 DOI: 10.1007/s40259-018-0289-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cell surface membrane proteins comprise a wide array of structurally and functionally diverse proteins involved in a variety of important physiological and homeostatic processes. Complex integral membrane proteins, which are embedded in the lipid bilayer by multiple transmembrane-spanning helices, are represented by families of proteins that are important target classes for drug discovery. Such protein families include G-protein-coupled receptors, ion channels and transporters. Although these targets have typically been the domain of small-molecule drugs, the exquisite specificity of monoclonal antibodies offers a significant opportunity to selectively modulate these target proteins. Nevertheless, the isolation of antibodies with desired pharmacological functions has proved difficult because of technical challenges in preparing membrane protein antigens for antibody drug discovery. In this review, we describe recent progress in defining strategies for the generation of membrane protein antigens. We also describe antibody-isolation strategies that identify antibodies that bind the membrane protein and modulate protein function.
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9
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A function-blocking PAR4 antibody is markedly antithrombotic in the face of a hyperreactive PAR4 variant. Blood Adv 2019; 2:1283-1293. [PMID: 29884748 DOI: 10.1182/bloodadvances.2017015552] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 05/06/2018] [Indexed: 11/20/2022] Open
Abstract
Thrombin activates human platelets via 2 protease-activated receptors (PARs), PAR1 and PAR4, both of which are antithrombotic drug targets: a PAR1 inhibitor is approved for clinical use, and a PAR4 inhibitor is in trial. However, a common sequence variant in human PAR4 (rs773902, encoding Thr120 in place of Ala120) renders the receptor more sensitive to agonists and less sensitive to antagonists. Here, we develop the first human monoclonal function-blocking antibody to human PAR4 and show it provides equivalent efficacy against the Ala120 and Thr120 PAR4 variants. This candidate was generated from a panel of anti-PAR4 antibodies, was found to bind PAR4 with affinity (KD ≈ 0.4 nM) and selectivity (no detectable binding to any of PAR1, PAR2, or PAR3), and is capable of near-complete inhibition of thrombin cleavage of either the Ala120 or Thr120 PAR4 variant. Platelets from individuals expressing the Thr120 PAR4 variant exhibit increased thrombin-induced aggregation and phosphatidylserine exposure vs those with the Ala120 PAR4 variant, yet the PAR4 antibody inhibited these responses equivalently (50% inhibitory concentration, 4.3 vs 3.2 µg/mL against Ala120 and Thr120, respectively). Further, the antibody significantly impairs platelet procoagulant activity in an ex vivo thrombosis assay, with equivalent inhibition of fibrin formation and overall thrombus size in blood from individuals expressing the Ala120 or Thr120 PAR4 variant. These findings reveal antibody-mediated inhibition of PAR4 cleavage and activation provides robust antithrombotic activity independent of the rs773902 PAR4 sequence variant and provides rationale for such an approach for antithrombotic therapy targeting this receptor.
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10
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Ngo AT, Sheriff J, Rocheleau AD, Bucher M, Jones KR, Sepp ALI, Malone LE, Zigomalas A, Maloyan A, Bahou WF, Bluestein D, McCarty OJT, Haley KM. Assessment of neonatal, cord, and adult platelet granule trafficking and secretion. Platelets 2019; 31:68-78. [PMID: 30810440 PMCID: PMC6711836 DOI: 10.1080/09537104.2019.1573314] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 02/01/2019] [Accepted: 01/16/2019] [Indexed: 10/27/2022]
Abstract
Despite the transient hyporeactivity of neonatal platelets, full-term neonates do not display a bleeding tendency, suggesting potential compensatory mechanisms which allow for balanced and efficient neonatal hemostasis. This study aimed to utilize small-volume, whole blood platelet functional assays to assess the neonatal platelet response downstream of the hemostatic platelet agonists thrombin and adenosine diphosphate (ADP). Thrombin activates platelets via the protease-activated receptors (PARs) 1 and 4, whereas ADP signals via the receptors P2Y1 and P2Y12 as a positive feedback mediator of platelet activation. We observed that neonatal and cord blood-derived platelets exhibited diminished PAR1-mediated granule secretion and integrin activation relative to adult platelets, correlating to reduced PAR1 expression by neonatal platelets. PAR4-mediated granule secretion was blunted in neonatal platelets, correlating to lower PAR4 expression as compared to adult platelets, while PAR4 mediated GPIIb/IIIa activation was similar between neonatal and adult platelets. Under high shear stress, cord blood-derived platelets yielded similar thrombin generation rates but reduced phosphatidylserine expression as compared to adult platelets. Interestingly, we observed enhanced P2Y1/P2Y12-mediated dense granule trafficking in neonatal platelets relative to adults, although P2Y1/P2Y12 expression in neonatal, cord, and adult platelets were similar, suggesting that neonatal platelets may employ an ADP-mediated positive feedback loop as a potential compensatory mechanism for neonatal platelet hyporeactivity.
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Affiliation(s)
- Anh T.P. Ngo
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Jawaad Sheriff
- Department of Biomedical Engineering; Stony Brook
University, Stony Brook, NY, USA 11794
| | - Anne D. Rocheleau
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Matthew Bucher
- Knight Cardiovascular Institute, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
- Department of Obstetrics and Gynecology, Oregon Health
& Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Kendra R. Jones
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Anna-Liisa I. Sepp
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Lisa E. Malone
- Division of Hematology, Department of Medicine, Stony Brook
University, Stony Brook, NY, USA 11794
| | - Amanda Zigomalas
- Department of Biomedical Engineering; Stony Brook
University, Stony Brook, NY, USA 11794
| | - Alina Maloyan
- Knight Cardiovascular Institute, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
- Department of Obstetrics and Gynecology, Oregon Health
& Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Wadie F. Bahou
- Division of Hematology, Department of Medicine, Stony Brook
University, Stony Brook, NY, USA 11794
| | - Danny Bluestein
- Department of Biomedical Engineering; Stony Brook
University, Stony Brook, NY, USA 11794
| | - Owen J. T. McCarty
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Kristina M. Haley
- The Hemophilia Center, Oregon Health & Science
University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
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11
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Whitley MJ, Henke D, Ghazi A, Nieman M, Stoller M, Simon LM, Chen E, Vesci J, Holinstat M, McKenzie S, Shaw C, Edelstein L, Bray PF. The protease-activated receptor 4 Ala120Thr variant alters platelet responsiveness to low-dose thrombin and protease-activated receptor 4 desensitization, and is blocked by non-competitive P2Y 12 inhibition. J Thromb Haemost 2018; 16:2501-2514. [PMID: 30347494 PMCID: PMC6289679 DOI: 10.1111/jth.14318] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Indexed: 01/07/2023]
Abstract
Essentials The rs773902 SNP results in differences in platelet protease-activated receptor (PAR4) function. The functional consequences of rs773902 were analyzed in human platelets and stroke patients. rs773902 affects thrombin-induced platelet function, PAR4 desensitization, stroke association. Enhanced PAR4 Thr120 effects on platelet function are blocked by ticagrelor. SUMMARY: Background F2RL3 encodes protease-activated receptor (PAR) 4 and harbors an A/G single-nucleotide polymorphism (SNP) (rs773902) with racially dimorphic allelic frequencies. This SNP mediates an alanine to threonine substitution at residue 120 that alters platelet PAR4 activation by the artificial PAR4-activation peptide (PAR4-AP) AYPGKF. Objectives To determine the functional effects of rs773902 on stimulation by a physiological agonist, thrombin, and on antiplatelet antagonist activity. Methods Healthy human donors were screened and genotyped for rs773902. Platelet function in response to thrombin was assessed without and with antiplatelet antagonists. The association of rs773902 alleles with stroke was assessed in the Stroke Genetics Network study. Results As compared with rs773902 GG donors, platelets from rs773902 AA donors had increased aggregation in response to subnanomolar concentrations of thrombin, increased granule secretion, and decreased sensitivity to PAR4 desensitization. In the presence of PAR1 blockade, this genotype effect was abolished by higher concentrations of or longer exposure to thrombin. We were unable to detect a genotype effect on thrombin-induced PAR4 cleavage, dimerization, and lipid raft localization; however, rs773902 AA platelets required a three-fold higher level of PAR4-AP for receptor desensitization. Ticagrelor, but not vorapaxar, abolished the PAR4 variant effect on thrombin-induced platelet aggregation. A significant association of modest effect was detected between the rs773902 A allele and stroke. Conclusion The F2RL3 rs773902 SNP alters platelet reactivity to thrombin; the allelic effect requires P2Y12 , and is not affected by gender. Ticagrelor blocks the enhanced reactivity of rs773902 A platelets. PAR4 encoded by the rs773902 A allele is relatively resistant to desensitization and may contribute to stroke risk.
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Affiliation(s)
- M. J. Whitley
- The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA
| | - D.M. Henke
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX
| | - A. Ghazi
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX
| | - M. Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
| | - Michelle Stoller
- Program in Molecular Medicine and the Division of Hematology and Hematologic Malignancies, Department of Internal Medicine, University of Utah, Salt Lake City, UT
| | - L. M. Simon
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX
| | - E. Chen
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX
| | - J. Vesci
- The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA
| | - M. Holinstat
- Department of Pharmacology, University of Michigan, Ann Arbor, MI
| | - S.E. McKenzie
- The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA
| | - C.A. Shaw
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX
- Department of Statistics, Rice University, Houston, TX
| | - L.C. Edelstein
- The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA
| | - Paul F. Bray
- Program in Molecular Medicine and the Division of Hematology and Hematologic Malignancies, Department of Internal Medicine, University of Utah, Salt Lake City, UT
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13
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Tourdot BE, Stoveken H, Trumbo D, Yeung J, Kanthi Y, Edelstein LC, Bray PF, Tall GG, Holinstat M. Genetic Variant in Human PAR (Protease-Activated Receptor) 4 Enhances Thrombus Formation Resulting in Resistance to Antiplatelet Therapeutics. Arterioscler Thromb Vasc Biol 2018; 38:1632-1643. [PMID: 29748334 PMCID: PMC6023764 DOI: 10.1161/atvbaha.118.311112] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 04/24/2018] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Platelet activation after stimulation of PAR (protease-activated receptor) 4 is heightened in platelets from blacks compared with those from whites. The difference in PAR4 signaling by race is partially explained by a single-nucleotide variant in PAR4 encoding for either an alanine or threonine at amino acid 120 in the second transmembrane domain. The current study sought to determine whether the difference in PAR4 signaling by this PAR4 variant is because of biased Gq signaling and whether the difference in PAR4 activity results in resistance to traditional antiplatelet intervention. APPROACH AND RESULTS Membranes expressing human PAR4-120 variants were reconstituted with either Gq or G13 to determine the kinetics of G protein activation. The kinetics of Gq and G13 activation were both increased in membranes expressing PAR4-Thr120 compared with those expressing PAR4-Ala120. Further, inhibiting PAR4-mediated platelet activation by targeting COX (cyclooxygenase) and P2Y12 receptor was less effective in platelets from subjects expressing PAR4-Thr120 compared with PAR4-Ala120. Additionally, ex vivo thrombus formation in whole blood was evaluated at high shear to determine the relationship between PAR4 variant expression and response to antiplatelet drugs. Ex vivo thrombus formation was enhanced in blood from subjects expressing PAR4-Thr120 in the presence or absence of antiplatelet therapy. CONCLUSIONS Together, these data support that the signaling difference by the PAR4-120 variant results in the enhancement of both Gq and G13 activation and an increase in thrombus formation resulting in a potential resistance to traditional antiplatelet therapies targeting COX-1 and the P2Y12 receptor.
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Affiliation(s)
- Benjamin E Tourdot
- From the Department of Pharmacology (B.E.T., H.S., D.T., J.Y., G.G.T., M.H.)
| | - Hannah Stoveken
- From the Department of Pharmacology (B.E.T., H.S., D.T., J.Y., G.G.T., M.H.)
| | - Derek Trumbo
- From the Department of Pharmacology (B.E.T., H.S., D.T., J.Y., G.G.T., M.H.)
| | - Jennifer Yeung
- From the Department of Pharmacology (B.E.T., H.S., D.T., J.Y., G.G.T., M.H.)
| | - Yogendra Kanthi
- Division of Cardiovascular Medicine, Department of Internal Medicine (Y.K., M.H.), University of Michigan, Ann Arbor.,Ann Arbor Veterans Affairs Health System, MI (Y.K.)
| | - Leonard C Edelstein
- Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (L.C.E.)
| | - Paul F Bray
- Department of Internal Medicine, University of Utah, Salt Lake City (P.F.B.)
| | - Gregory G Tall
- From the Department of Pharmacology (B.E.T., H.S., D.T., J.Y., G.G.T., M.H.)
| | - Michael Holinstat
- From the Department of Pharmacology (B.E.T., H.S., D.T., J.Y., G.G.T., M.H.) .,Division of Cardiovascular Medicine, Department of Internal Medicine (Y.K., M.H.), University of Michigan, Ann Arbor
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14
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Rwibasira Rudinga G, Khan GJ, Kong Y. Protease-Activated Receptor 4 (PAR4): A Promising Target for Antiplatelet Therapy. Int J Mol Sci 2018; 19:E573. [PMID: 29443899 PMCID: PMC5855795 DOI: 10.3390/ijms19020573] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/09/2018] [Accepted: 02/09/2018] [Indexed: 12/29/2022] Open
Abstract
Cardiovascular diseases (CVDs) are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs), including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR). Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.
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Affiliation(s)
- Gamariel Rwibasira Rudinga
- School of Life Science & Technology, China Pharmaceutical University, 24 Tong Jia Street, Nanjing 210009, China.
| | - Ghulam Jilany Khan
- Jiangsu Center for Pharmacodynamics Research, Evaluation and Drug Screening, China Pharmaceutical University, Nanjing 210009, China.
| | - Yi Kong
- School of Life Science & Technology, China Pharmaceutical University, 24 Tong Jia Street, Nanjing 210009, China.
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15
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Opportunities for therapeutic antibodies directed at G-protein-coupled receptors. Nat Rev Drug Discov 2017; 16:787-810. [PMID: 28706220 DOI: 10.1038/nrd.2017.91] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
G-protein-coupled receptors (GPCRs) are activated by a diverse range of ligands, from large proteins and proteases to small peptides, metabolites, neurotransmitters and ions. They are expressed on all cells in the body and have key roles in physiology and homeostasis. As such, GPCRs are one of the most important target classes for therapeutic drug discovery. The development of drugs targeting GPCRs has therapeutic value across a wide range of diseases, including cancer, immune and inflammatory disorders as well as neurological and metabolic diseases. The progress made by targeting GPCRs with antibody-based therapeutics, as well as technical hurdles to overcome, are presented and discussed in this Review. Antibody therapeutics targeting C-C chemokine receptor type 4 (CCR4), CCR5 and calcitonin gene-related peptide (CGRP) are used as illustrative clinical case studies.
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16
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Discovery of functional monoclonal antibodies targeting G-protein-coupled receptors and ion channels. Biochem Soc Trans 2017; 44:831-7. [PMID: 27284048 DOI: 10.1042/bst20160028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Indexed: 11/17/2022]
Abstract
The development of recombinant antibody therapeutics is a significant area of growth in the pharmaceutical industry with almost 50 approved monoclonal antibodies on the market in the US and Europe. Despite this growth, however, certain classes of important molecular targets have remained intractable to therapeutic antibodies due to complexity of the target molecules. These complex target molecules include G-protein-coupled receptors and ion channels which represent a large potential target class for therapeutic intervention with monoclonal antibodies. Although these targets have typically been addressed by small molecule approaches, the exquisite specificity of antibodies provides a significant opportunity to provide selective modulation of these target proteins. Given this opportunity, substantial effort has been applied to address the technical challenges of targeting these complex membrane proteins with monoclonal antibodies. In this review recent progress made in the strategies for discovery of functional monoclonal antibodies for these challenging membrane protein targets is addressed.
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17
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Hamilton JR, Trejo J. Challenges and Opportunities in Protease-Activated Receptor Drug Development. Annu Rev Pharmacol Toxicol 2016; 57:349-373. [PMID: 27618736 DOI: 10.1146/annurev-pharmtox-011613-140016] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protease-activated receptors (PARs) are a unique class of G protein-coupled receptors (GPCRs) that transduce cellular responses to extracellular proteases. PARs have important functions in the vasculature, inflammation, and cancer and are important drug targets. A unique feature of PARs is their irreversible proteolytic mechanism of activation that results in the generation of a tethered ligand that cannot diffuse away. Despite the fact that GPCRs have proved to be the most successful class of druggable targets, the development of agents that target PARs specifically has been challenging. As a consequence, researchers have taken a remarkable diversity of approaches to develop pharmacological entities that modulate PAR function. Here, we present an overview of the diversity of therapeutic agents that have been developed against PARs. We further discuss PAR biased signaling and the influence of receptor compartmentalization, posttranslational modifications, and dimerization, which are important considerations for drug development.
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Affiliation(s)
- Justin R Hamilton
- Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria 3004, Australia
| | - JoAnn Trejo
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093;
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18
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Abstract
Arterial thrombosis (blood clot) is a common complication of many systemic diseases associated with chronic inflammation, including atherosclerosis, diabetes, obesity, cancer and chronic autoimmune rheumatologic disorders. Thrombi are the cause of most heart attacks, strokes and extremity loss, making thrombosis an extremely important public health problem. Since these thrombi stem from inappropriate platelet activation and subsequent coagulation, targeting these systems therapeutically has important clinical significance for developing safer treatments. Due to the complexities of the hemostatic system, in vitro experiments cannot replicate the blood-to-vessel wall interactions; therefore, in vivo studies are critical to understand pathological mechanisms of thrombus formation. To this end, various thrombosis models have been developed in mice. Among them, ferric chloride (FeCl3) induced vascular injury is a widely used model of occlusive thrombosis that reports platelet activation and aggregation in the context of an aseptic closed vascular system. This model is based on redox-induced endothelial cell injury, which is simple and sensitive to both anticoagulant and anti-platelets drugs. The time required for the development of a thrombus that occludes blood flow gives a quantitative measure of vascular injury, platelet activation and aggregation that is relevant to thrombotic diseases. We have significantly refined this FeCl3-induced vascular thrombosis model, which makes the data highly reproducible with minimal variation. Here we describe the model and present representative data from several experimental set-ups that demonstrate the utility of this model in thrombosis research.
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Affiliation(s)
- Wei Li
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University;
| | - Marvin Nieman
- Department of Pharmacology, Case Western Reserve University
| | - Anirban Sen Gupta
- Department of Biomedical Engineering, Case Western Reserve University
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19
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Smith TH, Coronel LJ, Li JG, Dores MR, Nieman MT, Trejo J. Protease-activated Receptor-4 Signaling and Trafficking Is Regulated by the Clathrin Adaptor Protein Complex-2 Independent of β-Arrestins. J Biol Chem 2016; 291:18453-64. [PMID: 27402844 DOI: 10.1074/jbc.m116.729285] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Indexed: 11/06/2022] Open
Abstract
Protease-activated receptor-4 (PAR4) is a G protein-coupled receptor (GPCR) for thrombin and is proteolytically activated, similar to the prototypical PAR1. Due to the irreversible activation of PAR1, receptor trafficking is intimately linked to signal regulation. However, unlike PAR1, the mechanisms that control PAR4 trafficking are not known. Here, we sought to define the mechanisms that control PAR4 trafficking and signaling. In HeLa cells depleted of clathrin by siRNA, activated PAR4 failed to internalize. Consistent with clathrin-mediated endocytosis, expression of a dynamin dominant-negative K44A mutant also blocked activated PAR4 internalization. However, unlike most GPCRs, PAR4 internalization occurred independently of β-arrestins and the receptor's C-tail domain. Rather, we discovered a highly conserved tyrosine-based motif in the third intracellular loop of PAR4 and found that the clathrin adaptor protein complex-2 (AP-2) is important for internalization. Depletion of AP-2 inhibited PAR4 internalization induced by agonist. In addition, mutation of the critical residues of the tyrosine-based motif disrupted agonist-induced PAR4 internalization. Using Dami megakaryocytic cells, we confirmed that AP-2 is required for agonist-induced internalization of endogenous PAR4. Moreover, inhibition of activated PAR4 internalization enhanced ERK1/2 signaling, whereas Akt signaling was markedly diminished. These findings indicate that activated PAR4 internalization requires AP-2 and a tyrosine-based motif and occurs independent of β-arrestins, unlike most classical GPCRs. Moreover, these findings are the first to show that internalization of activated PAR4 is linked to proper ERK1/2 and Akt activation.
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Affiliation(s)
- Thomas H Smith
- From the Biomedical Sciences Graduate Program and Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Luisa J Coronel
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Julia G Li
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Michael R Dores
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093, Department of Biology, Hofstra University, Hempstead, New York 11549, and
| | - Marvin T Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44016
| | - JoAnn Trejo
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093,
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20
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French SL, Hamilton JR. Protease-activated receptor 4: from structure to function and back again. Br J Pharmacol 2016; 173:2952-65. [PMID: 26844674 DOI: 10.1111/bph.13455] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 01/22/2016] [Accepted: 01/29/2016] [Indexed: 12/21/2022] Open
Abstract
Protease-activated receptors are a family of four GPCRs (PAR1-PAR4) with a number of unique attributes. Nearly two and a half decades after the discovery of the first PAR, an antagonist targeting this receptor has been approved for human use. The first-in-class PAR1 antagonist, vorapaxar, was approved for use in the USA in 2014 for the prevention of thrombotic cardiovascular events in patients with a history of myocardial infarction or with peripheral arterial disease. These recent developments indicate the clinical potential of manipulating PAR function. While much work has been aimed at uncovering the function of PAR1 and, to a lesser extent, PAR2, comparatively little is known regarding the pharmacology and physiology of PAR3 and PAR4. Recent studies have begun to develop the pharmacological and genetic tools required to study PAR4 function in detail, and there is now emerging evidence for the function of PAR4 in disease settings. In this review, we detail the discovery, structure, pharmacology, physiological significance and therapeutic potential of PAR4. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein-Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc.
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Affiliation(s)
- Shauna L French
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
| | - Justin R Hamilton
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia.
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