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Ismail A, Hayek SS. Role of Soluble Urokinase-Type Plasminogen Activator Receptor in Cardiovascular Disease. Curr Cardiol Rep 2023; 25:1797-1810. [PMID: 37948017 DOI: 10.1007/s11886-023-01991-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/01/2023] [Indexed: 11/12/2023]
Abstract
PURPOSE OF REVIEW Chronic inflammation is a major contributor to cardiovascular disease (CVD) risk. Soluble urokinase plasminogen activator receptor (suPAR) is an immune-derived glycoprotein that is strongly associated with atherosclerotic disease. This review summarizes evidence on suPAR's role in CVD pathogenesis and its potential as a prognostic indicator and therapeutic target. RECENT FINDINGS Clinical, genetic, and experimental evidence supports suPAR's role as a pathogenic factor in atherosclerosis. suPAR promotes atherosclerosis through modulation of monocyte activation and function. Clinically, elevated suPAR levels are linked to increased cardiovascular risk across diverse populations. Ongoing clinical trials are evaluating therapies targeting suPAR signaling. Current evidence positions suPAR as a regulator of myeloid cell function that contributes to vascular inflammation and subsequent cardiovascular events. Additional research is needed to determine whether suPAR measurement can improve CVD risk prediction and enable personalized management. Overall, suPAR is a promising immune-derived biomarker and target for reducing inflammation and cardiovascular risk.
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Affiliation(s)
- Anis Ismail
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, 1500 E Medical Center Dr, CVC #2709, Ann Arbor, 48109, MI, USA
| | - Salim S Hayek
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, 1500 E Medical Center Dr, CVC #2709, Ann Arbor, 48109, MI, USA.
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Bollain-y-Goytia JJ, Torres-Del-muro FDJ, Hernández-Martínez SP, Avalos-Díaz E, Herrera-Esparza R. suPAR and WT1 modify the adhesion of podocytes and are related to proteinuria in class IV lupus nephritis. J Transl Autoimmun 2023; 7:100216. [PMID: 37868110 PMCID: PMC10587709 DOI: 10.1016/j.jtauto.2023.100216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/02/2023] [Accepted: 10/06/2023] [Indexed: 10/24/2023] Open
Abstract
Introduction Lupus nephritis (LN) affects up to 60 % of the patients with Systemic Lupus Erythematosus (SLE) and renal damage progression is associated with proteinuria, caused in part by the integrity of the glomerular basement membrane (GBM) and by podocyte injury. The soluble urokinase plasminogen activator receptor (suPAR) and Wilms Tumor 1 (WT1) have been related to podocyte effacement and consequently with proteinuria which raises questions about its pathogenic role in LN. Objective Define whether suPAR levels and WT1 expression influence in podocyte anchorage destabilization in LN class IV. Materials and methods This is a cross-sectional study of cases and controls. We studied patients with SLE without renal involvement (n = 12), SLE and LN class IV with proteinuria ≤0.5 g/24 h (n = 12), LN class IV with proteinuria ≥0.5 g/24 h (n = 12) and compared them with renal tissue control (CR) (n = 12) and control sera (CS) (n = 12). The CR was integrated by cadaveric samples without SLE or renal involvement and the CS was integrated by healthy participants. The expression and cellular localization of WT1, urokinase-type plasminogen activator receptor (uPAR), ac-α-tubulin, vimentin, and β3-integrin was assessed by immunohistochemistry (IHC). The concentration of suPAR in serum was analyzed by enzyme-linked immunosorbent assay (ELISA). Results In patients with LN, the activation of anchoring proteins was increased, such as podocyte β3-integrin, as well as the acetylation of alpha-acetyl-tubulin and uPAR, in contrast to the decrease in vimentin; interestingly, the cellular localization of WT1 was cytoplasmic and the number of podocytes per glomerulus decreased. The concentrations of suPAR was increased in patients with LN. Conclusion The destabilization of podocyte anchorage modulated by β3-integrin activation, and tubulin acetylation, associated with decreased WT1 cytoplasmic expression, and increased suPAR levels could be involved in kidney damage in patients with LN class IV.
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Affiliation(s)
| | | | | | - Esperanza Avalos-Díaz
- Universidad Autónoma de Zacatecas, Department of Immunology, UACB. Guadalupe, Zacatecas, 98615, Mexico
| | - Rafael Herrera-Esparza
- Universidad Autónoma de Zacatecas, Department of Immunology, UACB. Guadalupe, Zacatecas, 98615, Mexico
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Zhu K, Mukherjee K, Wei C, Hayek SS, Collins A, Gu C, Corapi K, Altintas MM, Wang Y, Waikar SS, Bianco AC, Koch A, Tacke F, Reiser J, Sever S. The D2D3 form of uPAR acts as an immunotoxin and may cause diabetes and kidney disease. Sci Transl Med 2023; 15:eabq6492. [PMID: 37729431 DOI: 10.1126/scitranslmed.abq6492] [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: 04/21/2022] [Accepted: 08/31/2023] [Indexed: 09/22/2023]
Abstract
Soluble urokinase plasminogen activator receptor (suPAR) is a risk factor for kidney diseases. In addition to suPAR, proteolysis of membrane-bound uPAR results in circulating D1 and D2D3 proteins. We showed that when exposed to a high-fat diet, transgenic mice expressing D2D3 protein developed progressive kidney disease marked by microalbuminuria, elevated serum creatinine, and glomerular hypertrophy. D2D3 transgenic mice also exhibited insulin-dependent diabetes mellitus evidenced by decreased levels of insulin and C-peptide, impaired glucose-stimulated insulin secretion, decreased pancreatic β cell mass, and high fasting blood glucose. Injection of anti-uPAR antibody restored β cell mass and function in D2D3 transgenic mice. At the cellular level, the D2D3 protein impaired β cell proliferation and inhibited the bioenergetics of β cells, leading to dysregulated cytoskeletal dynamics and subsequent impairment in the maturation and trafficking of insulin granules. D2D3 protein was predominantly detected in the sera of patients with nephropathy and insulin-dependent diabetes mellitus. These sera inhibited glucose-stimulated insulin release from human islets in a D2D3-dependent manner. Our study showed that D2D3 injures the kidney and pancreas and suggests that targeting this protein could provide a therapy for kidney diseases and insulin-dependent diabetes mellitus.
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Affiliation(s)
- Ke Zhu
- Department of Medicine, Rush University Medical Center, Chicago, IL 60612, USA
| | - Kamalika Mukherjee
- Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Changli Wei
- Department of Medicine, Rush University Medical Center, Chicago, IL 60612, USA
| | - Salim S Hayek
- Division of Cardiology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Agnieszka Collins
- Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Changkyu Gu
- Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Kristin Corapi
- Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Mehmet M Altintas
- Department of Medicine, Rush University Medical Center, Chicago, IL 60612, USA
| | - Yong Wang
- Department of Surgery, University of Virginia, Charlottesville, VA 22903, USA
| | - Sushrut S Waikar
- Section of Nephrology, Boston University Chobanian & Avedisian School of Medicine and Boston Medical Center, Boston, MA 02129, USA
| | - Antonio C Bianco
- Division of Endocrinology, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Alexander Koch
- Department of Gastroenterology, Metabolic Diseases and Internal Intensive Care Medicine, University Hospital Aachen, 52072 Aachen, Germany
| | - Frank Tacke
- Department of Hepatology and Gastroenterology, Charité - Universitätsmedizin Berlin, 13353 Berlin, Germany
| | - Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, IL 60612, USA
| | - Sanja Sever
- Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Charlestown, MA 02129, USA
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Severity Biomarkers in Puumala Hantavirus Infection. Viruses 2021; 14:v14010045. [PMID: 35062248 PMCID: PMC8778356 DOI: 10.3390/v14010045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/16/2021] [Accepted: 12/23/2021] [Indexed: 12/12/2022] Open
Abstract
Annually, over 10,000 cases of hemorrhagic fever with renal syndrome (HFRS) are diagnosed in Europe. Puumala hantavirus (PUUV) causes most of the European HFRS cases. PUUV causes usually a relatively mild disease, which is rarely fatal. However, the severity of the infection varies greatly, and factors affecting the severity are mostly unrevealed. Host genes are known to have an effect. The typical clinical features in PUUV infection include acute kidney injury, thrombocytopenia, and increased vascular permeability. The primary target of hantavirus is the endothelium of the vessels of different organs. Although PUUV does not cause direct cytopathology of the endothelial cells, remarkable changes in both the barrier function of the endothelium and the function of the infected endothelial cells occur. Host immune or inflammatory mechanisms are probably important in the development of the capillary leakage. Several immunoinflammatory biomarkers have been studied in the context of assessing the severity of HFRS caused by PUUV. Most of them are not used in clinical practice, but the increasing knowledge about the biomarkers has elucidated the pathogenesis of PUUV infection.
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Rasmussen LJH, Petersen JEV, Eugen-Olsen J. Soluble Urokinase Plasminogen Activator Receptor (suPAR) as a Biomarker of Systemic Chronic Inflammation. Front Immunol 2021; 12:780641. [PMID: 34925360 PMCID: PMC8674945 DOI: 10.3389/fimmu.2021.780641] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 11/09/2021] [Indexed: 01/08/2023] Open
Abstract
Systemic chronic inflammation (SCI) is persistent, health-damaging, low-grade inflammation that plays a major role in immunosenescence and in development and progression of many diseases. But currently, there are no recognized standard biomarkers to assess SCI levels alone, and SCI is typically measured by combining biomarkers of acute inflammation and infection, e.g., CRP, IL-6, and TNFα. In this review, we highlight 10 properties and characteristics that are shared by the blood protein soluble urokinase plasminogen activator receptor (suPAR) and SCI, supporting the argument that suPAR is a biomarker of SCI: (1) Expression and release of suPAR is upregulated by immune activation; (2) uPAR and suPAR exert pro-inflammatory functions; (3) suPAR is associated with the amount of circulating immune cells; (4) Blood suPAR levels correlate with the levels of established inflammatory biomarkers; (5) suPAR is minimally affected by acute changes and short-term influences, in contrast to many currently used markers of systemic inflammation; (6) Like SCI, suPAR is non-specifically associated with multiple diseases; (7) suPAR and SCI both predict morbidity and mortality; (8) suPAR and SCI share the same risk factors; (9) suPAR is associated with risk factors and outcomes of inflammation above and beyond other inflammatory biomarkers; (10) The suPAR level can be reduced by anti-inflammatory interventions and treatment of disease. Assessing SCI has the potential to inform risk for morbidity and mortality. Blood suPAR is a newer biomarker which may, in fact, be a biomarker of SCI since it is stably associated with inflammation and immune activation; shares the same risk factors as many age-related diseases; is both elevated by and predicts age-related diseases. There is strong evidence that suPAR is a prognostic marker of adverse events, morbidity, and mortality. It is associated with immune activity and prognosis across diverse conditions, including kidney disease, cardiovascular disease, cancer, diabetes, and inflammatory disorders. Thus, we think it likely represents a common underlying disease-process shared by many diseases; that is, SCI. We review the supporting literature and propose a research agenda that can help test the hypothesis that suPAR indexes SCI, with the potential of becoming the new gold standard for measuring SCI.
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Affiliation(s)
- Line Jee Hartmann Rasmussen
- Department of Clinical Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark
- Department of Psychology and Neuroscience, Duke University, Durham, NC, United States
| | - Jens Emil Vang Petersen
- Division of Infectious Diseases, Duke University School of Medicine, Durham, NC, United States
| | - Jesper Eugen-Olsen
- Department of Clinical Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark
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Li X, Qi D, Wang MY, Ji K, Xie QL, Wang Y, Du SH, Fan HY. Salvianolic acid A attenuates steroid resistant nephrotic syndrome through suPAR/uPAR-αvβ3 signaling Inhibition. JOURNAL OF ETHNOPHARMACOLOGY 2021; 279:114351. [PMID: 34157324 DOI: 10.1016/j.jep.2021.114351] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 06/06/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Salvianolic acid A (SAA) is extracted from traditional Chinese medicine Salvia miltiorrhiza and is the main water-soluble and the biologically active ingredient. SAA possesses a variety of pharmacological activities and has an excellent protective effect on kidney disease, especially steroid resistant nephrotic syndrome (SRNS), and has advantages in improving the efficacy of glucocorticoids, but its mechanism needs to be further explored. PURPOSE The study was designed to explore the effect of suPAR and uPAR in SRNS patients and evaluate the potential effect of SAA in improving podocyte steroid resistance and explore its mechanism. METHODS AND MATERIALS The ELISA kits were used to detect the levels of suPAR in the blood and urine of subjects. The levels of uPAR, GRα, and GRβ expression in renal tissues of SRNS patients was detected by immunohistochemistry and analyzed using the Pearson method. In vitro studies, steroid resistance model was induced by the TNF-α and IFN-γ. The protein and mRNA expression of Nephrin, GR, GRα and GRβ were analyzed using western blot and qRT-PCR. The activity of GR-DNA binding was detected by using TransAM™ GR kits. Adriamycin further induced steroid resistance podocyte. Flow cytometry was used to detect the effect of SAA on podocyte apoptosis. ELISA assay was used to detect the suPAR expression in the podocyte supernatant. Western blot and qRT-PCR were used to detect the protein and mRNA expression of uPAR and Nephrin in podocytes. RESULTS The serum and urine levels of suPAR were conspicuously higher in SRNS patients than healthy volunteers and SSNS patients, and the expression of uPAR in renal tissue of SRNS patients is negatively correlated with GRα, but positively correlated with GRβ. The combination of TNF-α and IFN-γ could conspicuously increase the GRβ expression and reduce GRα/GRβ, and induce steroid resistance in podocytes. Moreover, we found that SAA could reduce the apoptosis of podocytes and suppress the expression of suPAR/uPAR, and increase the expression of Nephrin. CONCLUSION The level of suPAR and uPAR expression may have important value in predicting glucocorticoids resistance in patients with idiopathic nephrotic syndrome (INS). The combination of TNF-α and IFN-γ induce podocytes can establish steroid resistance model in vitro. SAA could improve glucocorticoids resistance of podocyte which can be attributed in part to regulate the suPAR/uPAR-αvβ3 signaling pathway.
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Affiliation(s)
- Xin Li
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Dong Qi
- Department of Nephrology, Yu-Huang-Ding Hospital/Qingdao University, 264000, Yantai, Shandong, PR China.
| | - Meng-Ying Wang
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Kai Ji
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Qun-Ling Xie
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Yu Wang
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Shi-Hao Du
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Hua-Ying Fan
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China.
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Wei C, Spear R, Hahm E, Reiser J. suPAR, a Circulating Kidney Disease Factor. Front Med (Lausanne) 2021; 8:745838. [PMID: 34692736 PMCID: PMC8526732 DOI: 10.3389/fmed.2021.745838] [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] [Received: 07/22/2021] [Accepted: 09/06/2021] [Indexed: 01/08/2023] Open
Abstract
Urokinase plasminogen activator receptor (uPAR) is a multifaceted, GPI-anchored three-domain protein. Release of the receptor results in variable levels of soluble uPAR (suPAR) in the blood circulation. suPAR levels have been linked to many disease states. In this mini-review, we discuss suPAR as a key circulating molecule mediating kidney disease with a particular focus on differently spliced isoforms.
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Affiliation(s)
- Changli Wei
- Department of Medicine, Rush University Medical Center, Chicago, IL, United States
| | - Ryan Spear
- Department of Medicine, Rush University Medical Center, Chicago, IL, United States
| | - Eunsil Hahm
- Department of Medicine, Rush University Medical Center, Chicago, IL, United States
| | - Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, IL, United States
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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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Thy PAL, Tran KH, Thi TYH, Thi MPP, Nguyen HS. The value of urinary soluble urokinase plasminogen activator receptor (suPAR) in children with nephrotic syndrome. AIMS MEDICAL SCIENCE 2021. [DOI: 10.3934/medsci.2021015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Nusshag C, Stütz A, Hägele S, Speer C, Kälble F, Eckert C, Brenner T, Weigand MA, Morath C, Reiser J, Zeier M, Krautkrämer E. Glomerular filtration barrier dysfunction in a self-limiting, RNA virus-induced glomerulopathy resembles findings in idiopathic nephrotic syndromes. Sci Rep 2020; 10:19117. [PMID: 33154421 PMCID: PMC7644703 DOI: 10.1038/s41598-020-76050-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 10/20/2020] [Indexed: 02/02/2023] Open
Abstract
Podocyte injury has recently been described as unifying feature in idiopathic nephrotic syndromes (INS). Puumala hantavirus (PUUV) infection represents a unique RNA virus-induced renal disease with significant proteinuria. The underlying pathomechanism is unclear. We hypothesized that PUUV infection results in podocyte injury, similar to findings in INS. We therefore analyzed standard markers of glomerular proteinuria (e.g. immunoglobulin G [IgG]), urinary nephrin excretion (podocyte injury) and serum levels of the soluble urokinase plasminogen activator receptor (suPAR), a proposed pathomechanically involved molecule in INS, in PUUV-infected patients. Hantavirus patients showed significantly increased urinary nephrin, IgG and serum suPAR concentrations compared to healthy controls. Nephrin and IgG levels were significantly higher in patients with severe proteinuria than with mild proteinuria, and nephrin correlated strongly with biomarkers of glomerular proteinuria over time. Congruently, electron microcopy analyses showed a focal podocyte foot process effacement. suPAR correlated significantly with urinary nephrin, IgG and albumin levels, suggesting suPAR as a pathophysiological mediator in podocyte dysfunction. In contrast to INS, proteinuria recovered autonomously in hantavirus patients. This study reveals podocyte injury as main cause of proteinuria in hantavirus patients. A better understanding of the regenerative nature of hantavirus-induced glomerulopathy may generate new therapeutic approaches for INS.
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Affiliation(s)
- Christian Nusshag
- Department of Nephrology, Heidelberg University Hospital, Im Neuenheimer Feld 162, 69120, Heidelberg, Germany. .,Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA.
| | - Alisa Stütz
- Department of Nephrology, Heidelberg University Hospital, Im Neuenheimer Feld 162, 69120, Heidelberg, Germany
| | - Stefan Hägele
- Department of Nephrology, Heidelberg University Hospital, Im Neuenheimer Feld 162, 69120, Heidelberg, Germany
| | - Claudius Speer
- Department of Nephrology, Heidelberg University Hospital, Im Neuenheimer Feld 162, 69120, Heidelberg, Germany
| | - Florian Kälble
- Department of Nephrology, Heidelberg University Hospital, Im Neuenheimer Feld 162, 69120, Heidelberg, Germany
| | - Christoph Eckert
- Department of Pathology, Heidelberg University Hospital, Heidelberg, Germany
| | - Thorsten Brenner
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, Essen, Germany
| | - Markus A Weigand
- Department of Anesthesiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Christian Morath
- Department of Nephrology, Heidelberg University Hospital, Im Neuenheimer Feld 162, 69120, Heidelberg, Germany
| | - Jochen Reiser
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Martin Zeier
- Department of Nephrology, Heidelberg University Hospital, Im Neuenheimer Feld 162, 69120, Heidelberg, Germany
| | - Ellen Krautkrämer
- Department of Nephrology, Heidelberg University Hospital, Im Neuenheimer Feld 162, 69120, Heidelberg, Germany
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Nusshag C, Reuß CJ, Dietrich M, Hecker A, Jungk C, Michalski D, Fiedler MO, Bernhard M, Beynon C, Weigand MA, Brenner T. [Focus nephrology : Intensive medical care studies from 2019/2020]. Anaesthesist 2020; 70:250-256. [PMID: 33103208 DOI: 10.1007/s00101-020-00856-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- C Nusshag
- Klinik für Nephrologie, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - C J Reuß
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - M Dietrich
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - A Hecker
- Klinik für Allgemein‑, Viszeral‑, Thorax‑, Transplantations- und Kinderchirurgie, Universitätsklinikum Gießen und Marburg, Standort Gießen, Gießen, Deutschland
| | - C Jungk
- Neurochirurgische Klinik, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - D Michalski
- Neurologische Intensivstation und Stroke Unit, Klinik und Poliklinik für Neurologie, Universitätsklinikum Leipzig AöR, Leipzig, Deutschland
| | - M O Fiedler
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - M Bernhard
- Zentrale Notaufnahme, Universitätsklinikum Düsseldorf, Düsseldorf, Deutschland
| | - C Beynon
- Neurochirurgische Klinik, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - M A Weigand
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Heidelberg, Deutschland.
| | - T Brenner
- Klinik für Anästhesiologie und Intensivmedizin, Universitätsklinikum Essen, Essen, Deutschland
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Further Evidence That the Soluble Urokinase Plasminogen Activator Receptor Does Not Directly Injure Mice or Human Podocytes. Transplantation 2020; 104:54-60. [PMID: 31449183 DOI: 10.1097/tp.0000000000002930] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND The role of the soluble urokinase plasminogen activator receptor (suPAR) in focal segmental glomerulosclerosis (FSGS) as the circulating factor or as a predictor of recurrence after transplantation remains controversial. Previously published studies in mice and isolated podocytes produced conflicting results on the effect of suPAR on podocyte injury, effacement of foot processes, and proteinuria. These discordant results were in part due to diverse experimental designs and different strains of mice. The aim of our study was to determine the reasons for the inconsistencies of the previous studies results with suPAR by using uniform methods and studies in different strains of mice. METHODS We utilized a primary culture of human podocytes and 2 mouse models, the wild type (WT) and the urokinase plasminogen activator receptor (uPAR) KO (uPAR), in an attempt to resolve the reported conflicting results. RESULTS In both WT and uPAR mouse models, injection of recombinant uPAR, even at a high dose (100 μg), did not induce proteinuria, effacement of podocytes, or disruption of the cytoskeleton. Injection of suPAR resulted in its deposition exclusively in the glomerular endothelial cells and not in the podocytes of WT mice and was not detected at the uPAR KO mice. Kidneys from patients with recurrent FSGS had negative immunostaining for uPAR. We also evaluated the effect of recombinant uPAR on primary culture of human podocytes. uPAR did not result in podocytes damage. CONCLUSIONS suPAR by itself is not the cause for direct podocyte injury, in vitro or in vivo. These findings suggest a more complex and still poorly understood role of suPAR in FSGS.
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Increased Serum Soluble Urokinase-Type Plasminogen Activator Receptor (suPAR) Levels in FSGS: A Meta-Analysis. J Immunol Res 2019; 2019:5679518. [PMID: 31089477 PMCID: PMC6476117 DOI: 10.1155/2019/5679518] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 12/01/2018] [Accepted: 01/20/2019] [Indexed: 12/12/2022] Open
Abstract
Introduction The soluble urokinase-type plasminogen activator receptor (suPAR) has been found to be elevated in primary focal segmental glomerulosclerosis (pFSGS). However, its usefulness as a biomarker for FSGS remains controversial. We conducted a meta-analysis aiming at investigating the significance of suPAR in diagnosing pFSGS. Methods Electronic databases (PubMed and EMBASE) were searched to identify studies comparing suPAR levels in FSGS patients and controls, from the earliest available date to May 1, 2018. A random-effects model with standardized mean difference (SMD) was used for meta-analyses. Risk of bias was assessed using the Newcastle-Ottawa quality assessment scale. Results A total of 187 articles were screened, and the final analysis included 13 articles. In comparison to healthy controls, serum suPAR levels were significantly increased in pFSGS patients (SMD, 1.07, 95% confidence interval (CI) 0.65 to 1.48; participants = 814; studies = 9, I 2 = 85%). Higher suPAR levels were also found in patients with pFSGS compared to those with minimal change disease (SMD 0.53, 95% CI 0.22 to 0.84). Of note, such a difference was not found in pediatric groups (SMD 0.42, 95% CI -0.13 to 0.96) while it was more evidently noted in adult patients (SMD 1.32, 95% CI 0.90 to 1.74). Serum suPAR levels did not differ between pFSGS patients in remission compared to those in active proteinuric state (SMD 0.29, 95% CI -0.30 to 0.88). Comparison with membranous nephropathy and IgA nephropathy showed no significant difference. Conclusions Our meta-analysis demonstrated that, in comparison to both healthy controls and controls with minimal change disease, suPAR levels were significantly higher in adult patients with pFSGS. suPAR levels did not differ between pFSGS patients during the initial period of diagnosis and those in remission.
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Mechanisms underlying modulation of podocyte TRPC6 channels by suPAR: Role of NADPH oxidases and Src family tyrosine kinases. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3527-3536. [PMID: 30293571 DOI: 10.1016/j.bbadis.2018.08.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/02/2018] [Accepted: 08/06/2018] [Indexed: 01/10/2023]
Abstract
The soluble urokinase receptor (suPAR) has been implicated in the pathogenesis of chronic kidney diseases (CKD) and may function as a circulating "permeability factor" driving primary focal and segmental glomerulosclerosis (FSGS). Here we examined the mechanisms whereby suPAR causes mobilization and increased activation of Ca2+-permeable TRPC6 channels, which are also implicated in FSGS. Treatment of immortalized mouse podocytes with recombinant suPAR for 24 h caused a marked increase in cytosolic reactive oxygen species (ROS) that required signaling through integrins. This effect was associated with increased assembly of active cell surface NADPH oxidase 2 (Nox2) complexes and was blocked by the Nox2 inhibitor apoycynin. Treatment with suPAR also evoked a functionally measurable increase in TRPC6 channels that was blocked by concurrent treatment with the ROS-quencher TEMPOL as well as by inhibition of Rac1, an essential component of active Nox2 complexes. Elevated ROS evoked by exposing cells to suPAR or H2O2 caused a marked increase in the abundance of tyrosine-phosphorylated proteins including Src, and suPAR-evoked Src activation was blocked by TEMPOL. Moreover, mobilization and increased activation of TRPC6 by suPAR or H2O2 was blocked by concurrent exposure to PP2, an inhibitor of Src family tyrosine kinases. These data suggest that suPAR induces oxidative stress in podocytes that in turn drives signaling through Src family kinases to upregulate TRPC6 channels. The combination of oxidative stress and altered Ca2+ signaling may contribute to loss of podocytes and progression of various forms of CKD.
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Campbell KN, Tumlin JA. Protecting Podocytes: A Key Target for Therapy of Focal Segmental Glomerulosclerosis. Am J Nephrol 2018; 47 Suppl 1:14-29. [PMID: 29852493 DOI: 10.1159/000481634] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Focal segmental glomerulosclerosis (FSGS) is a histologic pattern of injury demonstrated by renal biopsy that can arise from a diverse range of causes and mechanisms. It has an estimated incidence of 7 per 1 million and is the most common primary glomerular disorder leading to end-stage renal disease in the United States. This review focuses on damage to the podocyte and the consequences of this injury in patients with FSGS, the genetics of FSGS, and approaches to treatment with a focus on the effects on podocytes. SUMMARY The podocyte is central to the glomerular filtration barrier and is particularly vulnerable because of its highly differentiated post-mitotic phenotype. The progressive structural changes involved in the pathology of FSGS include podocyte foot process effacement, death of podocytes and exposure of the glomerular basement membrane, filtration of nonspecific plasma proteins, expansion of capillaries, misdirected filtration at points of synechiae, and mesangial matrix proliferation. Although damage to and death of podocytes can result from single-gene disorders, evidence also suggests a role for soluble factors, such as soluble urokinase-type plasminogen activator receptor, cardiotrophin-like cytokine-1, and anti-CD40 antibodies, that promote FSGS recurrence post transplant. Several classes of medications, including corticosteroids, calcineurin inhibitors, endothelin receptor antagonists, adrenocorticotropic hormone, and rituximab, have been shown to be effective for the treatment of FSGS and have been demonstrated to have significant protective effects on podocytes. Key Messages: Greater understanding of podocyte biology is essential to the identification of new treatment targets and medications for the management of patients with FSGS.
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Affiliation(s)
- Kirk N Campbell
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - James A Tumlin
- Department of Medicine, UT College of Medicine, University of Tennessee, Chattanooga, Tennessee, USA
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Staniszewska M, Dziedziejko V, Kwiatkowska E, Tkacz M, Puchałowicz K, Safranow K, Domanski L, Pawlik A. Plasma concentration of urokinase plasminogen activator receptor is a marker of kidney allograft function. Ir J Med Sci 2018; 187:1083-1087. [PMID: 29497975 DOI: 10.1007/s11845-018-1767-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 02/07/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Urokinase-type plasminogen activator receptor (uPAR) is found in a variety of cell types including monocytes, lymphocytes, macrophages, and endothelial cells and plays an important role in fibrinolysis and in the activation and chemotaxis of neutrophils and lymphocytes. In this study, we examined the correlation between uPAR plasma concentration and kidney allograft function. AIMS This study enrolled 78 Caucasian deceased-donor renal transplant recipients. METHODS Plasma concentrations of uPAR were measured using commercially available enzyme-linked immunosorbent assay (ELISA) kits. RESULTS We observed elevated with borderline significance (p = 0.095) uPAR plasma concentrations in patients with tubular atrophy. Plasma concentrations of uPAR showed strong statistically significant positive correlations with serum creatinine or urea and strong negative correlation with estimated glomerular filtration rate (eGFR). There was also a borderline positive correlation between uPAR plasma concentration and protein concentration in urine as well as the duration of hemodialysis. CONCLUSIONS The results of our study indicate that uPAR plasma concentrations in kidney allograft recipients are significantly negatively correlated with graft function and may be elevated in patients with tubular atrophy.
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Affiliation(s)
- Marzena Staniszewska
- Department of Physiology, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland
| | - Violetta Dziedziejko
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland
| | - Ewa Kwiatkowska
- Department of Nephrology, Transplantology and Internal Medicine, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland
| | - Marta Tkacz
- Department of Physiology, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland
| | - Kamila Puchałowicz
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland
| | - Krzysztof Safranow
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland
| | - Leszek Domanski
- Department of Nephrology, Transplantology and Internal Medicine, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland
| | - Andrzej Pawlik
- Department of Physiology, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland.
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17
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Schaefer F, Trachtman H, Wühl E, Kirchner M, Hayek SS, Anarat A, Duzova A, Mir S, Paripovic D, Yilmaz A, Lugani F, Arbeiter K, Litwin M, Oh J, Matteucci MC, Gellermann J, Wygoda S, Jankauskiene A, Klaus G, Dusek J, Testa S, Zurowska A, Caldas Afonso A, Tracy M, Wei C, Sever S, Smoyer W, Reiser J. Association of Serum Soluble Urokinase Receptor Levels With Progression of Kidney Disease in Children. JAMA Pediatr 2017; 171:e172914. [PMID: 28873129 PMCID: PMC6121753 DOI: 10.1001/jamapediatrics.2017.2914] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Importance Conventional methods to diagnose and monitor chronic kidney disease (CKD) in children, such as creatinine level and cystatin C-derived estimated glomerular filtration rate (eGFR) and assessment of proteinuria in spot or timed urine samples, are of limited value in identifying patients at risk of progressive kidney function loss. Serum soluble urokinase receptor (suPAR) levels strongly predict incident CKD stage 3 in adults. Objective To determine whether elevated suPAR levels are associated with renal disease progression in children with CKD. Design, Setting, and Participants Post hoc analysis of 2 prospectively followed up pediatric CKD cohorts, ie, the ESCAPE Trial (1999-2007) and the 4C Study (2010-2016), with serum suPAR level measured at enrollment and longitudinal eGFR measured prospectively. In the 2 trials, a total of 898 children were observed at 30 (ESCAPE Trial; n = 256) and 55 (4C Study; n = 642) tertiary care hospitals in 13 European countries. Renal diagnoses included congenital anomalies of the kidneys and urinary tract (n = 637 [70.9%]), tubulointerstitial nephropathies (n = 92 [10.2%]), glomerulopathies (n = 69 [7.7%]), postischemic CKD (n = 42 [4.7%]), and other CKD (n = 58 [6.5%]). Total follow-up duration was up to 7.9 years, and median follow-up was 3.1 years. Analyses were conducted from October 2016 to December 2016. Exposures Serum suPAR level was measured at enrollment, and eGFR was measured every 2 months in the ESCAPE Trial and every 6 months in the 4C Study. The primary end point of CKD progression was a composite of 50% eGFR loss, eGFR less than 10 mL/min/1.73 m2, or initiation of renal replacement therapy. Main Outcomes and Measures The primary end point in this study was renal survival, defined as a composite of 50% loss of GFR that persisted for at least 1 month, the start of renal replacement therapy, or an eGFR less than 10 mL/min/1.73 m2. Results Of the 898 included children, 560 (62.4%) were male, and the mean (SD) patient age at enrollment was 11.9 (3.5) years. The mean (SD) eGFR was 34 (16) mL/min/1.73 m2. The 5-year end point-free renal survival was 64.5% (95% CI, 57.4-71.7) in children with suPAR levels in the lowest quartile compared with 35.9% (95% CI, 28.7-43.0) in those in the highest quartile (P < .001). By multivariable analysis, the risk of attaining the end point was higher in children with glomerulopathies and increased with age, blood pressure, proteinuria, and lower eGFR at baseline. In patients with baseline eGFR greater than 40 mL/min/1.73 m2, higher log-transformed suPAR levels were associated with a higher risk of CKD progression after adjustment for traditional risk factors (hazard ratio, 5.12; 95% CI, 1.56-16.7; P = .007). Conclusions and Relevance Patients with high suPAR levels were more likely to have progression of their kidney disease. Further studies should determine whether suPAR levels can identify children at risk for future CKD.
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Affiliation(s)
- Franz Schaefer
- Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Howard Trachtman
- Department of Pediatrics, Division of Nephrology, New York University Langone Medical Center, New York
| | - Elke Wühl
- Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Marietta Kirchner
- Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany
| | - Salim S Hayek
- Emory Clinical Cardiovascular Research Institute, Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia
| | - Ali Anarat
- Department of Pediatric Nephrology, Faculty of Medicine, Cukurova University, Adana, Turkey
| | - Ali Duzova
- Pediatric Nephrology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Sevgi Mir
- Pediatric Nephrology, Ege University Faculty of Medicine, Izmir, Turkey
| | | | - Alev Yilmaz
- Department of Pediatric Nephrology, Istanbul Medical Faculty, Istanbul, Turkey
| | | | - Klaus Arbeiter
- Pediatric Nephrology, Vienna University Children's Hospital, Vienna, Austria
| | - Mieczyslaw Litwin
- Nephrology, Kidney Transplantation and Hypertension, Children's Memorial Health Institute, Warzaw, Poland
| | - Jun Oh
- Pediatric Nephrology, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maria Chiara Matteucci
- Division of Pediatric Nephrology, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy
| | - Jutta Gellermann
- Pediatric Nephrology, Charité Children's Hospital, Berlin, Germany
| | - Simone Wygoda
- Children's Dialysis Center, Hospital St Georg, Leipzig, Germany
| | | | - Günter Klaus
- KfH Kidney Center for Children, Marburg, Germany
| | - Jiri Dusek
- Pediatrics, University Hospital Motol, Prague, Czech Republic
| | - Sara Testa
- Pediatric Nephrology and Dialysis, Fondazione OSP Maggiore Policlinico, Milano, Italy
| | - Aleksandra Zurowska
- Department of Pediatric and Adolescent Nephrology, Medical University Gdańsk, Gdańsk, Poland
| | | | - Melissa Tracy
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
| | - Changli Wei
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
| | - Sanja Sever
- Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Charlestown
| | - William Smoyer
- The Research Institute at Nationwide Children's Hospital, The Ohio State University, Columbus
| | - Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
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18
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Czirok S, Fang L, Radovits T, Szabó G, Szénási G, Rosivall L, Merkely B, Kökény G. Cinaciguat ameliorates glomerular damage by reducing ERK1/2 activity and TGF-ß expression in type-1 diabetic rats. Sci Rep 2017; 7:11218. [PMID: 28894114 PMCID: PMC5593847 DOI: 10.1038/s41598-017-10125-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/03/2017] [Indexed: 01/07/2023] Open
Abstract
Decreased soluble guanylate cyclase activity and cGMP levels in diabetic kidneys were shown to influence the progression of nephropathy. The regulatory effects of soluble guanylate cyclase activators on renal signaling pathways are still unknown, we therefore investigated the renal molecular effects of the soluble guanylate cyclase activator cinaciguat in type-1 diabetic (T1DM) rats. Male adult Sprague-Dawley rats were divided into 2 groups after induction of T1DM with 60 mg/kg streptozotocin: DM, untreated (DM, n = 8) and 2) DM + cinaciguat (10 mg/kg per os daily, DM-Cin, n = 8). Non-diabetic untreated and cinaciguat treated rats served as controls (Co (n = 10) and Co-Cin (n = 10), respectively). Rats were treated for eight weeks, when renal functional and molecular analyses were performed. Cinaciguat attenuated the diabetes induced proteinuria, glomerulosclerosis and renal collagen-IV expression accompanied by 50% reduction of TIMP-1 expression. Cinaciguat treatment restored the glomerular cGMP content and soluble guanylate cyclase expression, and ameliorated the glomerular apoptosis (TUNEL positive cell number) and podocyte injury. These effects were accompanied by significantly reduced TGF-ß overexpression and ERK1/2 phosphorylation in cinaciguat treated diabetic kidneys. We conclude that the soluble guanylate cyclase activator cinaciguat ameliorated diabetes induced glomerular damage, apoptosis, podocyte injury and TIMP-1 overexpression by suppressing TGF-ß and ERK1/2 signaling.
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Affiliation(s)
- Szabina Czirok
- Institute of Pathophysiology, Semmelweis University, Budapest, Hungary
| | - Lilla Fang
- Institute of Pathophysiology, Semmelweis University, Budapest, Hungary
| | - Tamás Radovits
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Gábor Szabó
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Gábor Szénási
- Institute of Pathophysiology, Semmelweis University, Budapest, Hungary
| | - László Rosivall
- Institute of Pathophysiology, Semmelweis University, Budapest, Hungary
| | - Béla Merkely
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Gábor Kökény
- Institute of Pathophysiology, Semmelweis University, Budapest, Hungary.
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19
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Kim EY, Roshanravan H, Dryer SE. Changes in podocyte TRPC channels evoked by plasma and sera from patients with recurrent FSGS and by putative glomerular permeability factors. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2342-2354. [PMID: 28629718 PMCID: PMC5557291 DOI: 10.1016/j.bbadis.2017.06.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 06/13/2017] [Accepted: 06/15/2017] [Indexed: 12/13/2022]
Abstract
Primary forms of focal and segmental glomerulosclerosis (FSGS) are driven by circulating factors that cause dysfunction or loss podocytes. Rare genetic forms of FSGS can be caused by mutations in TRPC6, which encodes a Ca2+-permeable cationic channel expressed in mesangial cells and podocytes; and NPHS2, which encodes podocin, a TRPC6-binding protein expressed in podocyte slit diaphragm domains. Here we observed that exposing immortalized mouse podocytes to serum or plasma from recurrent FSGS patients for 24h increased the steady-state cell-surface abundance of TRPC6, accompanied by an increase in currents through endogenous TRPC6 channels evoked by a hypoosmotic stretch stimulus. These effects were mimicked by the soluble urokinase receptor (suPAR) and by tumor necrosis factor (TNF), circulating factors implicated in nephrotic syndromes. Most but not all of the recurrent FSGS plasma samples that we examined also caused a loss of podocin over a period of several hours. The loss of podocin was also seen following exposure to suPAR but not TNF. However, TNF increased the effects of suPAR on TRPC6 and podocin, and TNF and suPAR are required for the full effects of one of the recurrent FSGS plasma samples. The actions of FSGS plasma, suPAR and TNF on surface abundance of TRPC6 were blocked by cilengitide, an inhibitor of αvβ3-integrin signaling. These data suggest that primary FSGS is a heterogeneous condition mediated by multiple circulating factors, and support TRPC6 and αvβ3-integrin as potential therapeutic targets.
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Affiliation(s)
- Eun Young Kim
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - Hila Roshanravan
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - Stuart E Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA; Department of Medicine, Division of Nephrology, Baylor College of Medicine, Houston, TX, USA.
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20
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suPAR and chronic kidney disease-a podocyte story. Pflugers Arch 2017; 469:1017-1020. [PMID: 28689240 DOI: 10.1007/s00424-017-2026-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 06/23/2017] [Indexed: 10/19/2022]
Abstract
The soluble urokinase-type plasminogen activator receptor (suPAR) is a circulating signaling molecule derived from immature myeloid cells. Elevated levels of suPAR have been linked to the pathogenesis of the kidney disease focal and segmental glomerulosclerosis. Here, suPAR acts on podocytes by activating αvβ3 integrins. Large observational studies showed that suPAR also predicts chronic kidney disease incidence and progression by predating the disease by several years prior to any other known marker of renal dysfunction. suPAR is rapidly developing into a prime target for pharmacotherapy as its neutralization is forecasted to be feasible and safe.
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21
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Hahm E, Peev V, Reiser J. Extrarenal determinants of kidney filter function. Cell Tissue Res 2017; 369:211-216. [PMID: 28560690 DOI: 10.1007/s00441-017-2635-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 04/28/2017] [Indexed: 12/27/2022]
Abstract
The kidney is an organ involved in cross talk with many human organs. The link between the immune system and the kidney has been studied in some detail, although data precisely elucidating their interaction are sparse, in particular with regard to the function of the kidney filter apparatus. Current research suggests that an understanding of the impairment of this cross talk between the bone marrow, as a fundament of the immune system and the kidney will provide meaningful insights into the pathophysiological mechanisms of impaired kidney filter function. Circulating factors have long been implicated in the pathogenesis of idiopathic nephrotic syndrome, particularly focal segmental glomerulosclerosis (FSGS) and its recurrence. Soluble urokinase receptor (suPAR) has emerged as a circulating factor responsible for FSGS and also as an early predictive marker for the development of various renal diseases. The bone marrow has recently been revealed as a predominant source of suPAR with deleterious effects on the kidney filter. These new findings have led to bone marrow or hematopoietic stem cell transplants being considered as potential therapeutic options for preventing the post-transplantation recurrence of FSGS or even as a treatment for the original disease associated with high suPAR levels. Whereas bone marrow transplantation for patients with pre-existing chronic kidney disease is challenging, recent clinical trials have demonstrated the promising outcome of combined bone marrow and kidney transplantation in patients with kidney failure. In this review, with its brief update on suPAR, we describe the critical new role of the bone marrow in the pathogenesis of the kidney disease process and the functional connection between these two organs through the soluble mediator, suPAR. We also comment on the feasibility of bone marrow transplants for the treatment of patients with chronic renal failure arising from recurrent FSGS.
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Affiliation(s)
- Eunsil Hahm
- Department of Internal Medicine, Rush University Medical Center, Chicago, Ill., USA
| | - Vasil Peev
- Department of Internal Medicine, Rush University Medical Center, Chicago, Ill., USA. .,Rush University Transplant Program, 1725 W. Harrison Street, Suite 161, Chicago, IL, 60612, USA.
| | - Jochen Reiser
- Department of Internal Medicine, Rush University Medical Center, Chicago, Ill., USA
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22
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Abstract
Focal segmental glomerulosclerosis (FSGS) represents the most common primary glomerular disease responsible for the development of end-stage renal disease (ESRD) in the United States (US). The disease progresses from podocyte injury to chronic kidney disease (CKD), ultimately leading to total nephron degeneration. Extensive basic science research has been conducted to unwind the mechanisms of FSGS and, with those insights, understand major contributors of CKD in general. As a result, several putative molecules and pathways have been studied, all implicated in the disease; some serve, in addition, as early biomarkers. The ongoing research is currently focusing on understanding how these molecules and pathways can interplay and be utilized as potential diagnostic and therapeutic targets. Among these molecules, the soluble urokinase plasminogen activating receptor (suPAR) has been studied in detail, both clinically and from a basic science perspective. By now, it has emerged as the earliest and most robust marker of future CKD. Other circulating factors harming podocytes include anti-CD40 auto-antibody and possibly cardiotrophin-like cytokine factor-1. Understanding these factors will aid our efforts to ultimately cure FSGS and possibly treat a larger portion of CKD patients much more effectively.
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Affiliation(s)
- Vasil Peev
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Eunsil Hahm
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Jochen Reiser
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA
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23
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Bone marrow-derived immature myeloid cells are a main source of circulating suPAR contributing to proteinuric kidney disease. Nat Med 2016; 23:100-106. [PMID: 27941791 DOI: 10.1038/nm.4242] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 10/31/2016] [Indexed: 12/15/2022]
Abstract
Excess levels of protein in urine (proteinuria) is a hallmark of kidney disease that typically occurs in conjunction with diabetes, hypertension, gene mutations, toxins or infections but may also be of unknown cause (idiopathic). Systemic soluble urokinase plasminogen activator receptor (suPAR) is a circulating factor implicated in the onset and progression of chronic kidney disease (CKD), such as focal segmental glomerulosclerosis (FSGS). The cellular source(s) of elevated suPAR associated with future and progressing kidney disease is unclear, but is likely extra-renal, as the pathological uPAR is circulating and FSGS can recur even after a damaged kidney is replaced with a healthy donor organ. Here we report that bone marrow (BM) Gr-1lo immature myeloid cells are responsible for the elevated, pathological levels of suPAR, as evidenced by BM chimera and BM ablation and cell transfer studies. A marked increase of Gr-1lo myeloid cells was commonly found in the BM of proteinuric animals having high suPAR, and these cells efficiently transmit proteinuria when transferred to healthy mice. In accordance with the results seen in suPAR-associated proteinuric animal models, in which kidney damage is caused not by local podocyte-selective injury but more likely by systemic insults, a humanized xenograft model of FSGS resulted in an expansion of Gr-1lo cells in the BM, leading to high plasma suPAR and proteinuric kidney disease. Together, these results identify suPAR as a functional connection between the BM and the kidney, and they implicate BM immature myeloid cells as a key contributor to glomerular dysfunction.
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24
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Abstract
Genetic studies of hereditary forms of nephrotic syndrome have identified several proteins that are involved in regulating the permselective properties of the glomerular filtration system. Further extensive research has elucidated the complex molecular basis of the glomerular filtration barrier and clearly established the pivotal role of podocytes in the pathophysiology of glomerular diseases. Podocyte architecture is centred on focal adhesions and slit diaphragms - multiprotein signalling hubs that regulate cell morphology and function. A highly interconnected actin cytoskeleton enables podocytes to adapt in order to accommodate environmental changes and maintain an intact glomerular filtration barrier. Actin-based endocytosis has now emerged as a regulator of podocyte integrity, providing an impetus for understanding the precise mechanisms that underlie the steady-state control of focal adhesion and slit diaphragm components. This Review outlines the role of actin dynamics and endocytosis in podocyte biology, and discusses how molecular heterogeneity in glomerular disorders could be exploited to deliver more rational therapeutic interventions, paving the way for targeted medicine in nephrology.
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Circulating Permeability Factors in Primary Focal Segmental Glomerulosclerosis: A Review of Proposed Candidates. BIOMED RESEARCH INTERNATIONAL 2016; 2016:3765608. [PMID: 27200372 PMCID: PMC4856884 DOI: 10.1155/2016/3765608] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 02/22/2016] [Indexed: 12/20/2022]
Abstract
Primary focal segmental glomerulosclerosis (FSGS) is a major cause of the nephrotic syndrome and often leads to end-stage renal disease. This review focuses on circulating permeability factors in primary FSGS that have been implicated in the pathogenesis for a long time, partly due to the potential recurrence in renal allografts within hours after transplantation. Recently, three molecules have been proposed as a potential permeability factor by different groups: the soluble urokinase plasminogen activator receptor (suPAR), cardiotrophin-like cytokine factor-1 (CLCF-1), and CD40 antibodies. Both CLCF-1 and CD40 antibodies have not been validated by independent research groups yet. Since the identification of suPAR, different studies have questioned the validity of suPAR as a biomarker to distinguish primary FSGS from other proteinuric kidney diseases as well as suPAR's pathogenic role in podocyte damage. Researchers have suggested that cleaved molecules of suPAR have a pathogenic role in FSGS but further studies are needed to determine this role. In future studies, proposed standards for the research of the permeability factor should be carefully followed. The identification of the permeability factor in primary FSGS would be of great clinical relevance as it could influence potential individual treatment regimen.
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Abstract
Minimal change disease (MCD) is an important cause of nephrotic syndrome and is characterized by massive proteinuria and hypoalbuminemia, resulting in edema and hypercholesterolemia. The podocyte plays a key role in filtration and its disruption results in a dramatic loss of function leading to proteinuria. Immunologic disturbance has been suggested in the pathogenesis of MCD. Because of its clinical features, such as recurrent relapse/remission course, steroid response in most patients, and rare familial cases, a genetic defect has been thought to be less likely in MCD. Recent progress in whole-exome sequencing reveals pathogenic mutations in familial cases in steroid-sensitive nephrotic syndrome (SSNS) and sheds light on possible mechanisms and key molecules in podocytes in MCD. On the other hand, in the majority of cases, the existence of circulating permeability factors has been implicated along with T lymphocyte dysfunction. Observations of benefit with rituximab added B cell involvement to the disease. Animal models are unsatisfactory, and the humanized mouse may be a good model that well reflects MCD pathophysiology to investigate suggested “T cell dysfunction” directly related to podocytes
in vivo. Several candidate circulating factors and their effects on podocytes have been proposed but are still not sufficient to explain whole mechanisms and clinical features in MCD. Another circulating factor disease is focal segmental glomerulosclerosis (FSGS), and it is not clear if this is a distinct entity, or on the same spectrum, implicating the same circulating factor(s). These patients are mostly steroid resistant and often have a rapid relapse after transplantation. In clinical practice, predicting relapse or disease activity and response to steroids is important and is an area where novel biomarkers can be developed based on our growing knowledge of podocyte signaling pathways. In this review, we discuss recent findings in genetics and podocyte biology in MCD.
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Affiliation(s)
- Moin A Saleem
- Paediatric Renal Medicine, University of Bristol, Bristol, UK; Children's Renal Unit, Bristol Royal Hospital for Children, Bristol, UK
| | - Yasuko Kobayashi
- Paediatric Renal Medicine, University of Bristol, Bristol, UK; Department of Pediatrics, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
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27
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Chen JS, Chang LC, Wu CZ, Tseng TL, Lin JA, Lin YF, Cheng CW. Significance of the urokinase-type plasminogen activator and its receptor in the progression of focal segmental glomerulosclerosis in clinical and mouse models. J Biomed Sci 2016; 23:24. [PMID: 26846181 PMCID: PMC4743092 DOI: 10.1186/s12929-016-0242-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 01/26/2016] [Indexed: 11/14/2022] Open
Abstract
Background suPAR biomarker generally considered a pathogenic factor in FSGS. However, studies have been published that dispute this conclusion. The current study was designed to investigate the roles of uPA and suPAR in FSGS in clinical and mouse models. Methods Clinical subjects including those with biopsy-proven FSGS and MCD were enrolled. To verify the role of uPA in FSGS, Adriamycin was used to induce FSGS in uPA knockout (uPA−/−) and BALB/c (WT) mice. Proteinuria and suPAR, the cleaved/intact forms of the circulating suPAR, and possible proteases involving cleavage of the suPAR were also studied. Results FSGS clinical cases presented significantly higher serum levels of suPAR and Cr and lower serum levels of uPA. In the mice model, the uPA−/− group exhibited faster disease progression and worsening proteinuria than the WT group. In addition, the uPA−/− group had higher plasma suPAR levels, glomerular cell apoptosis, and dysregulation of the Th1/Th2 balance. In an analysis of suPAR variants in FSGS, both the intact and cleaved forms of the suPAR were higher in clinical subjects and the mouse model. However, the process of suPAR cleavage was not mediated by enzymatic activities of the uPA, elastase, or cathepsin G. Conclusions A deficiency of uPA accelerated the progression of Adriamycin-induced mouse FSGS model. Decrease of serum uPA levels may be an indicator of the progression of FSGS in clinical subjects and animal models.
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Affiliation(s)
- Jin-Shuen Chen
- Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Chenggong Road, Neihu District, Taipei, 114, Taiwan
| | - Li-Chien Chang
- School of Pharmacy, National Defense Medical Center, Taipei, Taiwan
| | - Chung-Ze Wu
- Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Tzu-Ling Tseng
- Biomedical Technology & Device Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
| | - Jui-An Lin
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, No. 250, Wu-Xing Street, Taipei, 110, Taiwan
| | - Yuh-Feng Lin
- Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, No. 250, Wu-Xing Street, Taipei, 110, Taiwan
| | - Chao-Wen Cheng
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, No. 250, Wu-Xing Street, Taipei, 110, Taiwan. .,Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.
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Wei C, Sigdel TK, Sarwal MM, Reiser J. Circulating CD40 autoantibody and suPAR synergy drives glomerular injury. ANNALS OF TRANSLATIONAL MEDICINE 2015; 3:300. [PMID: 26697460 DOI: 10.3978/j.issn.2305-5839.2015.11.08] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Changli Wei
- 1 Department of Medicine, Rush University Medical Center, Chicago, IL 60612, USA ; 2 Department of Surgery, University of California San Francisco, San Francisco, CA 94017, USA
| | - Tara K Sigdel
- 1 Department of Medicine, Rush University Medical Center, Chicago, IL 60612, USA ; 2 Department of Surgery, University of California San Francisco, San Francisco, CA 94017, USA
| | - Minnie M Sarwal
- 1 Department of Medicine, Rush University Medical Center, Chicago, IL 60612, USA ; 2 Department of Surgery, University of California San Francisco, San Francisco, CA 94017, USA
| | - Jochen Reiser
- 1 Department of Medicine, Rush University Medical Center, Chicago, IL 60612, USA ; 2 Department of Surgery, University of California San Francisco, San Francisco, CA 94017, USA
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