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Hamada M, Varkoly KS, Riyadh O, Beladi R, Munuswamy-Ramanujam G, Rawls A, Wilson-Rawls J, Chen H, McFadden G, Lucas AR. Urokinase-Type Plasminogen Activator Receptor (uPAR) in Inflammation and Disease: A Unique Inflammatory Pathway Activator. Biomedicines 2024; 12:1167. [PMID: 38927374 PMCID: PMC11201033 DOI: 10.3390/biomedicines12061167] [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: 03/26/2024] [Revised: 04/24/2024] [Accepted: 05/10/2024] [Indexed: 06/28/2024] Open
Abstract
The urokinase-type plasminogen activator receptor (uPAR) is a unique protease binding receptor, now recognized as a key regulator of inflammation. Initially, uPA/uPAR was considered thrombolytic (clot-dissolving); however, recent studies have demonstrated its predominant immunomodulatory functions in inflammation and cancer. The uPA/uPAR complex has a multifaceted central role in both normal physiological and also pathological responses. uPAR is expressed as a glycophosphatidylinositol (GPI)-linked receptor interacting with vitronectin, integrins, G protein-coupled receptors, and growth factor receptors within a large lipid raft. Through protein-to-protein interactions, cell surface uPAR modulates intracellular signaling, altering cellular adhesion and migration. The uPA/uPAR also modifies extracellular activity, activating plasminogen to form plasmin, which breaks down fibrin, dissolving clots and activating matrix metalloproteinases that lyse connective tissue, allowing immune and cancer cell invasion and releasing growth factors. uPAR is now recognized as a biomarker for inflammatory diseases and cancer; uPAR and soluble uPAR fragments (suPAR) are increased in viral sepsis (COVID-19), inflammatory bowel disease, and metastasis. Here, we provide a comprehensive overview of the structure, function, and current studies examining uPAR and suPAR as diagnostic markers and therapeutic targets. Understanding uPAR is central to developing diagnostic markers and the ongoing development of antibody, small-molecule, nanogel, and virus-derived immune-modulating treatments that target uPAR.
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Affiliation(s)
- Mostafa Hamada
- College of Medicine, Kansas City University, 1750 Independence Ave, Kansas City, MO 64106, USA; (M.H.); (O.R.)
| | - Kyle Steven Varkoly
- Department of Internal Medicine, McLaren Macomb Hospital, Michigan State University College of Human Medicine, 1000 Harrington St., Mt Clemens, MI 48043, USA
| | - Omer Riyadh
- College of Medicine, Kansas City University, 1750 Independence Ave, Kansas City, MO 64106, USA; (M.H.); (O.R.)
| | - Roxana Beladi
- Department of Neurosurgery, Ascension Providence Hospital, Michigan State University College of Human Medicine, 16001 W Nine Mile Rd, Southfield, MI 48075, USA;
| | - Ganesh Munuswamy-Ramanujam
- Molecular Biology and Immunobiology Division, Interdisciplinary Institute of Indian System of Medicine, SRM Institute of Science and Technology, Kattankulathur 603203, India;
| | - Alan Rawls
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ 85281, USA; (A.R.); (J.W.-R.)
| | - Jeanne Wilson-Rawls
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ 85281, USA; (A.R.); (J.W.-R.)
| | - Hao Chen
- Department of Tumor Center, Lanzhou University Second Hospital, Lanzhou 730030, China;
| | - Grant McFadden
- Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, 727 E Tyler St., Tempe, AZ 85287, USA;
| | - Alexandra R. Lucas
- Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, 727 E Tyler St., Tempe, AZ 85287, USA;
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2
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Chen YQ, Yang Y, Zhen EY, Beyer TP, Li H, Wen Y, Ehsani M, Jackson N, Xie K, Jung H, Scheithauer JL, Kumari A, Birrane G, Russell AM, Balasubramaniam D, Liao Z, Siegel RW, Qian Y, Ploug M, Young SG, Konrad RJ. Carboxyl-terminal sequences in APOA5 are important for suppressing ANGPTL3/8 activity. Proc Natl Acad Sci U S A 2024; 121:e2322332121. [PMID: 38625948 PMCID: PMC11046700 DOI: 10.1073/pnas.2322332121] [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: 12/24/2023] [Accepted: 03/16/2024] [Indexed: 04/18/2024] Open
Abstract
Apolipoprotein AV (APOA5) lowers plasma triglyceride (TG) levels by binding to the angiopoietin-like protein 3/8 complex (ANGPTL3/8) and suppressing its capacity to inhibit lipoprotein lipase (LPL) catalytic activity and its ability to detach LPL from binding sites within capillaries. However, the sequences in APOA5 that are required for suppressing ANGPTL3/8 activity have never been defined. A clue to the identity of those sequences was the presence of severe hypertriglyceridemia in two patients harboring an APOA5 mutation that truncates APOA5 by 35 residues ("APOA5Δ35"). We found that wild-type (WT) human APOA5, but not APOA5Δ35, suppressed ANGPTL3/8's ability to inhibit LPL catalytic activity. To pursue that finding, we prepared a mutant mouse APOA5 protein lacking 40 C-terminal amino acids ("APOA5Δ40"). Mouse WT-APOA5, but not APOA5Δ40, suppressed ANGPTL3/8's capacity to inhibit LPL catalytic activity and sharply reduced plasma TG levels in mice. WT-APOA5, but not APOA5Δ40, increased intracapillary LPL levels and reduced plasma TG levels in Apoa5-/- mice (where TG levels are high and intravascular LPL levels are low). Also, WT-APOA5, but not APOA5Δ40, blocked the ability of ANGPTL3/8 to detach LPL from cultured cells. Finally, an antibody against a synthetic peptide corresponding to the last 26 amino acids of mouse APOA5 reduced intracapillary LPL levels and increased plasma TG levels in WT mice. We conclude that C-terminal sequences in APOA5 are crucial for suppressing ANGPTL3/8 activity in vitro and for regulating intracapillary LPL levels and plasma TG levels in vivo.
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Affiliation(s)
- Yan Q. Chen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
| | - Ye Yang
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Eugene Y. Zhen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
| | - Thomas P. Beyer
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
| | - Hongxia Li
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
| | - Yi Wen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
| | - Mariam Ehsani
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
| | - Nicholas Jackson
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Katherine Xie
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Hyesoo Jung
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Julia L. Scheithauer
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Anni Kumari
- Finsen Laboratory, Centre for Cancer and Organ Diseases, Copenhagen University Hospital-Rigshospitalet, DK-2200Copenhagen N, Denmark
- Finsen Laboratory, Biotech Research and Innovation Centre, University of Copenhagen, DK-2200Copenhagen N, Denmark
| | - Gabriel Birrane
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Boston, MA02215
| | - Anna M. Russell
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
| | | | - Zhongping Liao
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
| | - Robert W. Siegel
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
| | - Yuewei Qian
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
| | - Michael Ploug
- Finsen Laboratory, Centre for Cancer and Organ Diseases, Copenhagen University Hospital-Rigshospitalet, DK-2200Copenhagen N, Denmark
- Finsen Laboratory, Biotech Research and Innovation Centre, University of Copenhagen, DK-2200Copenhagen N, Denmark
| | - Stephen G. Young
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Robert J. Konrad
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN462585
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3
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Sutta A, Leemans NN, Ploug M, Rosbjerg A, Del Agua Villa C, Pérez-Alós L, Cyranka L, Vincek AS, de Garay T, Rivera K, Bayarri-Olmos R. CL-11 circulates in serum as functionally distinct isoforms. FASEB J 2024; 38:e23543. [PMID: 38466278 DOI: 10.1096/fj.202301765r] [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: 08/31/2023] [Revised: 01/08/2024] [Accepted: 02/23/2024] [Indexed: 03/12/2024]
Abstract
Collectin-11 (CL-11) is a pattern recognition molecule of the lectin pathway capable of interacting with collectin-10 (CL-10) and the MASPs to activate the complement cascade. Alternative splicing of the COLEC11 gene gives rise to two different isoforms found in serum (A and D). These isoforms vary in the length of their collagen-like region, which is involved in the stabilization of the trimeric subunit and the interaction with the MASPs. Here we aim at elucidating the biological differences of naturally occurring CL-11 isoforms A and D. We produced recombinant CL-11 as independent isoforms (CL-11A and CL-11D) and together with CL-10 (CL-10/11A, CL-10/11D). Both CL-11 isoforms associated with CL-10, but CL-11D did so to a lesser extent. CL-10/11 heterocomplexes were composed of trimeric subunits of CL-10 and CL-11, as opposed to CL-10 and CL-11 homotrimers. Heterocomplexes were more stable and migrated with higher apparent molecular weights. Immunoprecipitation of serum CL-11 and subsequent mass spectrometry analysis confirmed that native CL-11 circulates in the form of CL-10/11 heterocomplexes that associate with MASP-1, and MASP-3, but not necessarily MASP-2. Despite a shorter collagen region, CL-11D was capable to bind to the MASPs, suggesting that the missing exon 4 is not required for MASP association CL-11D had a reduced ligand binding compared to full-length CL-11A. Based on its reduced ability to oligomerize, form CL-10/11 heterocomplexes, and bind to ligands, we hypothesize that CL-11D may have a limited complement activation potential compared to full-length CL-11A.
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Affiliation(s)
- Adrian Sutta
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
- Recombinant Protein and Antibody Unit, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
| | - Nelia Nina Leemans
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
| | - Michael Ploug
- Finsen Laboratory, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Anne Rosbjerg
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
- Recombinant Protein and Antibody Unit, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
| | - Christian Del Agua Villa
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
- Recombinant Protein and Antibody Unit, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
| | - Laura Pérez-Alós
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
| | - Leon Cyranka
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
| | - Adam S Vincek
- Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | - Keith Rivera
- Mass Spectrometry Shared Resource, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA
| | - Rafael Bayarri-Olmos
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
- Recombinant Protein and Antibody Unit, Copenhagen University Hospital: Rigshospital, Copenhagen, Denmark
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4
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Code C, Qiu D, Solov’yov IA, Lee JG, Shin HC, Roland C, Sagui C, Houde D, Rand KD, Jørgensen TJD. Conformationally Restricted Glycopeptide Backbone Inhibits Gas-Phase H/D Scrambling between Glycan and Peptide Moieties. J Am Chem Soc 2023; 145:23925-23938. [PMID: 37883679 PMCID: PMC10636759 DOI: 10.1021/jacs.3c04068] [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: 04/19/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/28/2023]
Abstract
Protein glycosylation is a common post-translational modification on extracellular proteins. The conformational dynamics of several glycoproteins have been characterized by hydrogen/deuterium exchange mass spectrometry (HDX-MS). However, it is, in most cases, not possible to extract information about glycan conformation and dynamics due to the general difficulty of separating the deuterium content of the glycan from that of the peptide (in particular, for O-linked glycans). Here, we investigate whether the fragmentation of protonated glycopeptides by collision-induced dissociation (CID) can be used to determine the solution-specific deuterium content of the glycan. Central to this concept is that glycopeptides can undergo a facile loss of glycans upon CID, thereby allowing for the determination of their masses. However, an essential prerequisite is that hydrogen and deuterium (H/D) scrambling can be kept in check. Therefore, we have measured the degree of scrambling upon glycosidic bond cleavage in glycopeptides that differ in the conformational flexibility of their backbone and glycosylation pattern. Our results show that complete scrambling precedes the glycosidic bond cleavage in normal glycopeptides derived from a glycoprotein; i.e., all labile hydrogens have undergone positional randomization prior to loss of the glycan. In contrast, the glycosidic bond cleavage occurs without any scrambling in the glycopeptide antibiotic vancomycin, reflecting that the glycan cannot interact with the peptide moiety due to a conformationally restricted backbone as revealed by molecular dynamics simulations. Scrambling is also inhibited, albeit to a lesser degree, in the conformationally restricted glycopeptides ristocetin and its pseudoaglycone, demonstrating that scrambling depends on an intricate interplay between the flexibility and proximity of the glycan and the peptide backbone.
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Affiliation(s)
- Christian Code
- Department
of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Danwen Qiu
- Department
of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Ilia A. Solov’yov
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
- Department
of Physics, Carl von Ossietzky University
Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Research
Centre for Neurosensory Science, Carl von
Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Center
for Nanoscale Dynamics (CENAD), Carl von
Ossietzky Universität Oldenburg Institut für Physik, Ammerländer Heerstr. 114-118, 26129 Oldenburg, Germany
| | - Jung-Goo Lee
- Center for
Molecular Intelligence, The State University
of New York (SUNY), Korea,
119 Songdo Munwha-ro, Yeonsu-gu, 21985 Incheon, Korea
| | - Hyeon-Cheol Shin
- Center for
Molecular Intelligence, The State University
of New York (SUNY), Korea,
119 Songdo Munwha-ro, Yeonsu-gu, 21985 Incheon, Korea
| | - Christopher Roland
- Department
of Physics, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Celeste Sagui
- Department
of Physics, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Damian Houde
- Department
of Protein Pharmaceutical Development, Biogen, Cambridge, Massachusetts 02142, United States
| | - Kasper D. Rand
- Department
of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Thomas J. D. Jørgensen
- Department
of Biochemistry and Molecular Biology, University
of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark
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5
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Yu S, Sui Y, Wang J, Li Y, Li H, Cao Y, Chen L, Jiang L, Yuan C, Huang M. Crystal structure and cellular functions of uPAR dimer. Nat Commun 2022; 13:1665. [PMID: 35351875 PMCID: PMC8964761 DOI: 10.1038/s41467-022-29344-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 01/25/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractReceptor dimerization of urokinase-type plasminogen activator receptor (uPAR) was previously identified at protein level and on cell surface. Recently, a dimeric form of mouse uPAR isoform 2 was proposed to induce kidney disease. Here, we report the crystal structure of human uPAR dimer at 2.96 Å. The structure reveals enormous conformational changes of the dimer compared to the monomeric structure: D1 of uPAR opens up into a large expanded ring that captures a β-hairpin loop of a neighboring uPAR to form an expanded β-sheet, leading to an elongated, highly intertwined dimeric uPAR. Based on the structure, we identify E49P as a mutation promoting dimer formation. The mutation increases receptor binding to the amino terminal fragment of its primary ligand uPA, induces the receptor to distribute to the basal membrane, promotes cell proliferation, and alters cell morphology via β1 integrin signaling. These results reveal the structural basis for uPAR dimerization, its effect on cellular functions, and provide a basis to further study this multifunctional receptor.
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6
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Metrangolo V, Ploug M, Engelholm LH. The Urokinase Receptor (uPAR) as a "Trojan Horse" in Targeted Cancer Therapy: Challenges and Opportunities. Cancers (Basel) 2021; 13:cancers13215376. [PMID: 34771541 PMCID: PMC8582577 DOI: 10.3390/cancers13215376] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 12/23/2022] Open
Abstract
Simple Summary Discovered more than three decades ago, the urokinase-type plasminogen activator receptor (uPAR) has now firmly established itself as a versatile molecular target holding promise for the treatment of aggressive malignancies. The copious abundance of uPAR in virtually all human cancerous tissues versus their healthy counterparts has fostered a gradual shift in the therapeutic landscape targeting this receptor from function inhibition to cytotoxic approaches to selectively eradicate the uPAR-expressing cells by delivering a targeted cytotoxic insult. Multiple avenues are being explored in a preclinical setting, including the more innovative immune- or stroma targeting therapies. This review discusses the current state of these strategies, their potentialities, and challenges, along with future directions in the field of uPAR targeting. Abstract One of the largest challenges to the implementation of precision oncology is identifying and validating selective tumor-driving targets to enhance the therapeutic efficacy while limiting off-target toxicity. In this context, the urokinase-type plasminogen activator receptor (uPAR) has progressively emerged as a promising therapeutic target in the management of aggressive malignancies. By focalizing the plasminogen activation cascade and subsequent extracellular proteolysis on the cell surface of migrating cells, uPAR endows malignant cells with a high proteolytic and migratory potential to dissolve the restraining extracellular matrix (ECM) barriers and metastasize to distant sites. uPAR is also assumed to choreograph multiple other neoplastic stages via a complex molecular interplay with distinct cancer-associated signaling pathways. Accordingly, high uPAR expression is observed in virtually all human cancers and is frequently associated with poor patient prognosis and survival. The promising therapeutic potential unveiled by the pleiotropic nature of this receptor has prompted the development of distinct targeted intervention strategies. The present review will focus on recently emerged cytotoxic approaches emphasizing the novel technologies and related limits hindering their application in the clinical setting. Finally, future research directions and emerging opportunities in the field of uPAR targeting are also discussed.
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Affiliation(s)
- Virginia Metrangolo
- The Finsen Laboratory, Rigshospitalet, DK-2200 Copenhagen, Denmark; (V.M.); (M.P.)
- Biotech Research & Innovation Centre (BRIC), Department of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Michael Ploug
- The Finsen Laboratory, Rigshospitalet, DK-2200 Copenhagen, Denmark; (V.M.); (M.P.)
- Biotech Research & Innovation Centre (BRIC), Department of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Lars H. Engelholm
- The Finsen Laboratory, Rigshospitalet, DK-2200 Copenhagen, Denmark; (V.M.); (M.P.)
- Biotech Research & Innovation Centre (BRIC), Department of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Correspondence: ; Tel.: +45-31-43-20-77
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7
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Leth JM, Ploug M. Targeting the Urokinase-Type Plasminogen Activator Receptor (uPAR) in Human Diseases With a View to Non-invasive Imaging and Therapeutic Intervention. Front Cell Dev Biol 2021; 9:732015. [PMID: 34490277 PMCID: PMC8417595 DOI: 10.3389/fcell.2021.732015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 07/26/2021] [Indexed: 12/31/2022] Open
Abstract
The interaction between the serine protease urokinase-type plasminogen activator (uPA) and its glycolipid-anchored receptor (uPAR) focalizes plasminogen activation to cell surfaces, thereby regulating extravascular fibrinolysis, cell adhesion, and migration. uPAR belongs to the Ly6/uPAR (LU) gene superfamily and the high-affinity binding site for uPA is assembled by a dynamic association of its three consecutive LU domains. In most human solid cancers, uPAR is expressed at the invasive areas of the tumor-stromal microenvironment. High levels of uPAR in resected tumors or shed to the plasma of cancer patients are robustly associated with poor prognosis and increased risk of relapse and metastasis. Over the years, a plethora of different strategies to inhibit uPA and uPAR function have been designed and investigated in vitro and in vivo in mouse models, but so far none have been implemented in the clinics. In recent years, uPAR-targeting with the intent of cytotoxic eradication of uPAR-expressing cells have nonetheless gained increasing momentum. Another avenue that is currently being explored is non-invasive imaging with specific uPAR-targeted reporter-molecules containing positron emitting radionuclides or near-infrared (NIR) florescence probes with the overarching aim of being able to: (i) localize disease dissemination using positron emission tomography (PET) and (ii) assist fluorescence guided surgery using optical imaging. In this review, we will discuss these advancements with special emphasis on applications using a small 9-mer peptide antagonist that targets uPAR with high affinity.
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Affiliation(s)
- Julie Maja Leth
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Michael Ploug
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
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8
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Kristensen KK, Leth-Espensen KZ, Kumari A, Grønnemose AL, Lund-Winther AM, Young SG, Ploug M. GPIHBP1 and ANGPTL4 Utilize Protein Disorder to Orchestrate Order in Plasma Triglyceride Metabolism and Regulate Compartmentalization of LPL Activity. Front Cell Dev Biol 2021; 9:702508. [PMID: 34336854 PMCID: PMC8319833 DOI: 10.3389/fcell.2021.702508] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/23/2021] [Indexed: 12/12/2022] Open
Abstract
Intravascular processing of triglyceride-rich lipoproteins (TRLs) is crucial for delivery of dietary lipids fueling energy metabolism in heart and skeletal muscle and for storage in white adipose tissue. During the last decade, mechanisms underlying focal lipolytic processing of TRLs along the luminal surface of capillaries have been clarified by fresh insights into the functions of lipoprotein lipase (LPL); LPL's dedicated transporter protein, glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1); and its endogenous inhibitors, angiopoietin-like (ANGPTL) proteins 3, 4, and 8. Key discoveries in LPL biology include solving the crystal structure of LPL, showing LPL is catalytically active as a monomer rather than as a homodimer, and that the borderline stability of LPL's hydrolase domain is crucial for the regulation of LPL activity. Another key discovery was understanding how ANGPTL4 regulates LPL activity. The binding of ANGPTL4 to LPL sequences adjacent to the catalytic cavity triggers cooperative and sequential unfolding of LPL's hydrolase domain resulting in irreversible collapse of the catalytic cavity and loss of LPL activity. Recent studies have highlighted the importance of the ANGPTL3-ANGPTL8 complex for endocrine regulation of LPL activity in oxidative organs (e.g., heart, skeletal muscle, brown adipose tissue), but the molecular mechanisms have not been fully defined. New insights have also been gained into LPL-GPIHBP1 interactions and how GPIHBP1 moves LPL to its site of action in the capillary lumen. GPIHBP1 is an atypical member of the LU (Ly6/uPAR) domain protein superfamily, containing an intrinsically disordered and highly acidic N-terminal extension and a disulfide bond-rich three-fingered LU domain. Both the disordered acidic domain and the folded LU domain are crucial for the stability and transport of LPL, and for modulating its susceptibility to ANGPTL4-mediated unfolding. This review focuses on recent advances in the biology and biochemistry of crucial proteins for intravascular lipolysis.
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Affiliation(s)
- Kristian Kølby Kristensen
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Katrine Zinck Leth-Espensen
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Anni Kumari
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Anne Louise Grønnemose
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Anne-Marie Lund-Winther
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Stephen G Young
- Departments of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Michael Ploug
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
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9
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The intrinsic instability of the hydrolase domain of lipoprotein lipase facilitates its inactivation by ANGPTL4-catalyzed unfolding. Proc Natl Acad Sci U S A 2021; 118:2026650118. [PMID: 33723082 DOI: 10.1073/pnas.2026650118] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The complex between lipoprotein lipase (LPL) and its endothelial receptor (GPIHBP1) is responsible for the lipolytic processing of triglyceride-rich lipoproteins (TRLs) along the capillary lumen, a physiologic process that releases lipid nutrients for vital organs such as heart and skeletal muscle. LPL activity is regulated in a tissue-specific manner by endogenous inhibitors (angiopoietin-like [ANGPTL] proteins 3, 4, and 8), but the molecular mechanisms are incompletely understood. ANGPTL4 catalyzes the inactivation of LPL monomers by triggering the irreversible unfolding of LPL's α/β-hydrolase domain. Here, we show that this unfolding is initiated by the binding of ANGPTL4 to sequences near LPL's catalytic site, including β2, β3-α3, and the lid. Using pulse-labeling hydrogen‒deuterium exchange mass spectrometry, we found that ANGPTL4 binding initiates conformational changes that are nucleated on β3-α3 and progress to β5 and β4-α4, ultimately leading to the irreversible unfolding of regions that form LPL's catalytic pocket. LPL unfolding is context dependent and varies with the thermal stability of LPL's α/β-hydrolase domain (T m of 34.8 °C). GPIHBP1 binding dramatically increases LPL stability (T m of 57.6 °C), while ANGPTL4 lowers the onset of LPL unfolding by ∼20 °C, both for LPL and LPL•GPIHBP1 complexes. These observations explain why the binding of GPIHBP1 to LPL retards the kinetics of ANGPTL4-mediated LPL inactivation at 37 °C but does not fully suppress inactivation. The allosteric mechanism by which ANGPTL4 catalyzes the irreversible unfolding and inactivation of LPL is an unprecedented pathway for regulating intravascular lipid metabolism.
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Xu D, Bum-Erdene K, Leth JM, Ghozayel MK, Ploug M, Meroueh SO. Small-Molecule Inhibition of the uPAR ⋅ uPA Interaction by Conformational Selection. ChemMedChem 2020; 16:377-387. [PMID: 33107192 DOI: 10.1002/cmdc.202000558] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 09/25/2020] [Indexed: 12/12/2022]
Abstract
The urokinase receptor (uPAR) is a cell surface receptor that binds to the serine protease urokinase-type plasminogen activator (uPA) with high affinity. This interaction is beneficial for extravascular fibrin clearance, but it has also been associated with a broad range of pathological conditions including cancer, atherosclerosis, and kidney disease. Here, starting with a small molecule that we previously discovered by virtual screening and cheminformatics analysis, we design and synthesize several derivatives that were tested for binding and inhibition of the uPAR ⋅ uPA interaction. To confirm the binding site and establish a binding mode of the compounds, we carried out biophysical studies using uPAR mutants, among them uPARH47C-N259C , a mutant previously developed to mimic the structure of uPA-bound uPAR. Remarkably, a substantial increase in potency is observed for inhibition of uPARH47C-N259C binding to uPA compared to wild-type uPAR, consistent with our use of the structure of uPAR in its uPA-bound state to design small-molecule uPAR ⋅ uPA antagonists. Combined with the biophysical studies, molecular docking followed by extensive explicit-solvent molecular dynamics simulations and MM-GBSA free energy calculations yielded the most favorable binding pose of the compound. Collectively, these results suggest that potent inhibition of uPAR binding to uPA with small molecules will likely only be achieved by developing small molecules that exhibit high-affinity to solution apo structures of uPAR, rather than uPA-bound structures of the receptor.
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Affiliation(s)
- David Xu
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Khuchtumur Bum-Erdene
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Julie M Leth
- Finsen Laboratory, Rigshospitalet, 2200, Copenhagen N, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Mona K Ghozayel
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Michael Ploug
- Finsen Laboratory, Rigshospitalet, 2200, Copenhagen N, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Samy O Meroueh
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Unfolding of monomeric lipoprotein lipase by ANGPTL4: Insight into the regulation of plasma triglyceride metabolism. Proc Natl Acad Sci U S A 2020; 117:4337-4346. [PMID: 32034094 DOI: 10.1073/pnas.1920202117] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The binding of lipoprotein lipase (LPL) to GPIHBP1 focuses the intravascular hydrolysis of triglyceride-rich lipoproteins on the surface of capillary endothelial cells. This process provides essential lipid nutrients for vital tissues (e.g., heart, skeletal muscle, and adipose tissue). Deficiencies in either LPL or GPIHBP1 impair triglyceride hydrolysis, resulting in severe hypertriglyceridemia. The activity of LPL in tissues is regulated by angiopoietin-like proteins 3, 4, and 8 (ANGPTL). Dogma has held that these ANGPTLs inactivate LPL by converting LPL homodimers into monomers, rendering them highly susceptible to spontaneous unfolding and loss of enzymatic activity. Here, we show that binding of an LPL-specific monoclonal antibody (5D2) to the tryptophan-rich lipid-binding loop in the carboxyl terminus of LPL prevents homodimer formation and forces LPL into a monomeric state. Of note, 5D2-bound LPL monomers are as stable as LPL homodimers (i.e., they are not more prone to unfolding), but they remain highly susceptible to ANGPTL4-catalyzed unfolding and inactivation. Binding of GPIHBP1 to LPL alone or to 5D2-bound LPL counteracts ANGPTL4-mediated unfolding of LPL. In conclusion, ANGPTL4-mediated inactivation of LPL, accomplished by catalyzing the unfolding of LPL, does not require the conversion of LPL homodimers into monomers. Thus, our findings necessitate changes to long-standing dogma on mechanisms for LPL inactivation by ANGPTL proteins. At the same time, our findings align well with insights into LPL function from the recent crystal structure of the LPL•GPIHBP1 complex.
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Leth JM, Leth-Espensen KZ, Kristensen KK, Kumari A, Lund Winther AM, Young SG, Ploug M. Evolution and Medical Significance of LU Domain-Containing Proteins. Int J Mol Sci 2019; 20:ijms20112760. [PMID: 31195646 PMCID: PMC6600238 DOI: 10.3390/ijms20112760] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 12/13/2022] Open
Abstract
Proteins containing Ly6/uPAR (LU) domains exhibit very diverse biological functions and have broad taxonomic distributions in eukaryotes. In general, they adopt a characteristic three-fingered folding topology with three long loops projecting from a disulfide-rich globular core. The majority of the members of this protein domain family contain only a single LU domain, which can be secreted, glycolipid anchored, or constitute the extracellular ligand binding domain of type-I membrane proteins. Nonetheless, a few proteins contain multiple LU domains, for example, the urokinase receptor uPAR, C4.4A, and Haldisin. In the current review, we will discuss evolutionary aspects of this protein domain family with special emphasis on variations in their consensus disulfide bond patterns. Furthermore, we will present selected cases where missense mutations in LU domain-containing proteins leads to dysfunctional proteins that are causally linked to genesis of human disease.
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Affiliation(s)
- Julie Maja Leth
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Katrine Zinck Leth-Espensen
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Kristian Kølby Kristensen
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Anni Kumari
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Anne-Marie Lund Winther
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Michael Ploug
- Finsen Laboratory, Ole Maaloes Vej 5, Righospitalet, DK-2200 Copenhagen, Denmark.
- Biotechnology Research Innovation Centre (BRIC), Ole Maaloes Vej 5, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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Liu M, Lin L, Høyer-Hansen G, Ploug M, Li H, Jiang L, Yuan C, Li J, Huang M. Crystal structure of the unoccupied murine urokinase-type plasminogen activator receptor (uPAR) reveals a tightly packed DII-DIII unit. FEBS Lett 2019; 593:1236-1247. [PMID: 31044429 DOI: 10.1002/1873-3468.13397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/07/2019] [Accepted: 04/22/2019] [Indexed: 12/16/2022]
Abstract
The urokinase-type plasminogen activator receptor (uPAR) is a cell surface receptor that is capable of binding to a range of extracellular proteins and triggering a series of proteolytic and signaling events. Previous structural studies of uPAR with its ligands uPA and vitronectin revealed that its three domains (DI, DII, and DIII) form a large hydrophobic cavity to accommodate uPA. In the present study, the structure of unoccupied murine uPAR (muPAR) is determined. The structure of DII and DIII of muPAR is well defined and forms a compact globular unit, while DI could not be traced. Molecular dynamic simulations further confirm the rigid binding interface between DII and DIII. This study shows overall structural flexibility of uPAR in the absence of uPA.
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Affiliation(s)
- Min Liu
- College of Biological Science and Engineering, Fuzhou University, China.,College of Life Science, Fujian Normal University, Fuzhou, China
| | - Lin Lin
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Gunilla Høyer-Hansen
- Biotechnology Research Innovation Centre (BRIC), University of Copenhagen, Denmark.,Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark
| | - Michael Ploug
- Biotechnology Research Innovation Centre (BRIC), University of Copenhagen, Denmark.,Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark
| | - Hanlin Li
- College of Chemistry, Fuzhou University, China
| | | | - Cai Yuan
- College of Biological Science and Engineering, Fuzhou University, China
| | - Jinyu Li
- College of Chemistry, Fuzhou University, China
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