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Caster DJ, Powell DW. One antigen closer to understanding membranous nephropathy. Kidney Int 2023; 104:242-244. [PMID: 37479386 DOI: 10.1016/j.kint.2023.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 05/08/2023] [Indexed: 07/23/2023]
Abstract
Membranous nephropathy is an immune-mediated kidney disease characterized by subepithelial immune deposits. Through the utilization of advanced proteomic techniques, multiple target antigens have been identified, including those associated with primary and secondary etiologies. Nonsteroidal anti-inflammatory drugs represent an important secondary cause of membranous nephropathy. In this study by Sethi et al., advanced proteomic techniques identify proprotein convertase subtilisin/kexin type 6 as a target antigen in nonsteroidal anti-inflammatory drug-associated membranous nephropathy.
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Affiliation(s)
- Dawn J Caster
- Division of Nephrology and Hypertension, University of Louisville School of Medicine, Louisville, Kentucky, USA.
| | - David W Powell
- Division of Nephrology and Hypertension, University of Louisville School of Medicine, Louisville, Kentucky, USA; Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, Kentucky, USA
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Cummins TD, Powell DW, Wilkey DW, Brady MP, Benz FW, Barati MT, Caster DJ, Klein JB, Merchant ML. Quantitative Mass Spectrometry Normalization in Urine Biomarker Analysis in Nephrotic Syndrome. Glomerular Dis 2022; 2:121-131. [PMID: 36199623 PMCID: PMC9529004 DOI: 10.1159/000522217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Chronic kidney disease (CKD) affects 30 million adults, costs ~$79 billion dollars (2016) in Medicare expenditures, and is the ninth leading cause of death in the United States. The disease is silent or undiagnosed in almost half of people with severely reduced kidney function. Urine provides an ideal biofluid that is accessible to high-sensitivity mass spectrometry-based proteomic interrogation and is an indicator of renal homeostasis. While the accurate and precise diagnosis and better disease management of CKD can be aided using urine biomarkers, their discovery in excessive protein or nephrotic urine samples can present challenges. In this work we present a mass spectrometry-based method utilizing multiplex tandem mass tag (TMT) quantification and improved protein quantification using reporter ion normalization to urinary creatinine to analyze urinary proteins from patients with a form of nephrotic syndrome (FSGS). A comparative analysis was performed for urine from patients in remission versus active disease flare. Two-dimensional LC-MS/MS TMT quantitative analysis identified over 1058 urine proteins, 580 proteins with 2 peptides or greater and quantifiable. Normalization of TMT abundance values to creatinine per ml of urine concentrated reduced variability in 2D-TMT-LC-MS/MS experiments. Univariate and multivariate analyses showed that 27 proteins were significantly increased in proteinuric disease flare. Hierarchical heatmap clustering showed that SERPINA1 and ORM1 were >1.5 fold increased in active disease versus remission urine samples. ELISA validation of SERPINA1 and ORM1 abundance agreed with our quantitative TMT proteomics analysis. These findings provide support for the utility of this method for identification of novel diagnostic markers of CKD and identify SERPINA1 and ORM1 as promising candidate diagnostic markers for FSGS.
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Affiliation(s)
- Timothy D. Cummins
- Kidney Disease Program and Clinical Proteomics Center, University of Louisville School of Medicine, Louisville, Kentucky, USA,Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, Kentucky, USA,*Timothy D. Cummins,
| | - David W. Powell
- Kidney Disease Program and Clinical Proteomics Center, University of Louisville School of Medicine, Louisville, Kentucky, USA,Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Daniel W. Wilkey
- Kidney Disease Program and Clinical Proteomics Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Makayla P. Brady
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Fredrick W. Benz
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Michelle T. Barati
- Kidney Disease Program and Clinical Proteomics Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Dawn J. Caster
- Kidney Disease Program and Clinical Proteomics Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Jon B. Klein
- Kidney Disease Program and Clinical Proteomics Center, University of Louisville School of Medicine, Louisville, Kentucky, USA,Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, Kentucky, USA,Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Michael L. Merchant
- Kidney Disease Program and Clinical Proteomics Center, University of Louisville School of Medicine, Louisville, Kentucky, USA,Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
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Caster DJ, Korte EA, Merchant ML, Klein JB, Barati MT, Joglekar A, Wilkey DW, Coventry S, Hata J, Rovin BH, Harley JB, Namjou-Khales B, McLeish KR, Powell DW. Patients with Proliferative Lupus Nephritis Have Autoantibodies That React to Moesin and Demonstrate Increased Glomerular Moesin Expression. J Clin Med 2021; 10:jcm10040793. [PMID: 33669337 PMCID: PMC7920286 DOI: 10.3390/jcm10040793] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/28/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
Kidney involvement in systemic lupus erythematosus (SLE)—termed lupus nephritis (LN)—is a severe manifestation of SLE that can lead to end-stage kidney disease (ESKD). LN is characterized by immune complex deposition and inflammation in the glomerulus. We tested the hypothesis that autoantibodies targeting podocyte and glomerular cell proteins contribute to the development of immune complex formation in LN. We used Western blotting with SLE sera from patients with and without LN to identify target antigens in human glomerular and cultured human-derived podocyte membrane proteins. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), we identified the proteins in the gel regions corresponding to reactive bands observed with sera from LN patients. We identified 102 proteins that were present in both the podocyte and glomerular samples. We identified 10 high-probability candidates, including moesin, using bioinformatic analysis. Confirmation of moesin as a target antigen was conducted using immunohistochemical analysis (IHC) of kidney biopsy tissue and enzyme-linked immunosorbent assay (ELISA) to detect circulating antibodies. By IHC, biopsies from patients with proliferative lupus nephritis (PLN, class III/IV) demonstrated significantly increased glomerular expression of moesin (p < 0.01). By ELISA, patients with proliferative LN demonstrated significantly increased antibodies against moesin (p < 0.01). This suggests that moesin is a target glomerular antigen in lupus nephritis.
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Affiliation(s)
- Dawn J. Caster
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA; (E.A.K.); (M.L.M.); (J.B.K.); (M.T.B.); (A.J.); (D.W.W.); (K.R.M.); (D.W.P.)
- Correspondence: ; Tel.: +1-502-852-5757
| | - Erik A. Korte
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA; (E.A.K.); (M.L.M.); (J.B.K.); (M.T.B.); (A.J.); (D.W.W.); (K.R.M.); (D.W.P.)
| | - Michael L. Merchant
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA; (E.A.K.); (M.L.M.); (J.B.K.); (M.T.B.); (A.J.); (D.W.W.); (K.R.M.); (D.W.P.)
| | - Jon B. Klein
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA; (E.A.K.); (M.L.M.); (J.B.K.); (M.T.B.); (A.J.); (D.W.W.); (K.R.M.); (D.W.P.)
- Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206, USA
| | - Michelle T. Barati
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA; (E.A.K.); (M.L.M.); (J.B.K.); (M.T.B.); (A.J.); (D.W.W.); (K.R.M.); (D.W.P.)
| | - Ami Joglekar
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA; (E.A.K.); (M.L.M.); (J.B.K.); (M.T.B.); (A.J.); (D.W.W.); (K.R.M.); (D.W.P.)
| | - Daniel W. Wilkey
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA; (E.A.K.); (M.L.M.); (J.B.K.); (M.T.B.); (A.J.); (D.W.W.); (K.R.M.); (D.W.P.)
| | - Susan Coventry
- Pathology Department, Norton Children’s Hospital, Louisville, KY 40202, USA; (S.C.); (J.H.)
| | - Jessica Hata
- Pathology Department, Norton Children’s Hospital, Louisville, KY 40202, USA; (S.C.); (J.H.)
| | - Brad H. Rovin
- Department of Medicine, The Ohio State University, Columbus, OH 43210, USA;
| | - John B. Harley
- Center for Autoimmune Genomics and Etiology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA; (J.B.H.); (B.N.-K.)
- US Department of Veterans Affairs Medical Center, Cincinnati, OH 45220, USA
| | - Bahram Namjou-Khales
- Center for Autoimmune Genomics and Etiology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA; (J.B.H.); (B.N.-K.)
| | - Kenneth R. McLeish
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA; (E.A.K.); (M.L.M.); (J.B.K.); (M.T.B.); (A.J.); (D.W.W.); (K.R.M.); (D.W.P.)
| | - David W. Powell
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA; (E.A.K.); (M.L.M.); (J.B.K.); (M.T.B.); (A.J.); (D.W.W.); (K.R.M.); (D.W.P.)
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Abstract
SLE is a complex autoimmune disease with genetic, epigenetic, immune-regulatory, environmental and hormonal factors. Kidney inflammation and injury, termed lupus nephritis (LN), occurs in over half of patients with SLE and is a leading cause of disability and death. There is a high degree of short-term and long-term side effects associated with current LN therapies and they are not effective for many patients. Thus, novel therapies with reduced toxicity and improved efficacy are drastically needed. Many of the known LN susceptibility genes have functions that mediate inflammation via cytokine/chemokine production and activation of myeloid and B cells. Understanding the cellular and molecular mechanisms mediated by these variant gene products provides valuable insight for the development of improved and personalised diagnostics and therapeutics. This review describes variants in the TNIP1 (tumour necrosis factor α-induced protein 3-interacting protein 1) gene associated with risks for SLE and LN and potential roles for loss of function of its protein product ABIN1 in the activation of myeloid and B-cell-mediated injury in LN.
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Affiliation(s)
- Makayla P Brady
- Department of Medicine, University of Louisville, Louisville, Kentucky, USA
| | - Erik A Korte
- Bluewater Diagnostics Laboratory, Mt. Washington, Kentucky, USA
| | - Dawn J Caster
- Department of Medicine, University of Louisville, Louisville, Kentucky, USA
| | - David W Powell
- Department of Medicine, University of Louisville, Louisville, Kentucky, USA
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Powell DW, Brady MP, Barati MT, Caster DJ. TNIP1/ABIN1 mutation contributes to lupus nephritis via chemokine IP-10 induction. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.224.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Abstract
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease. Kidney inflammation or lupus nephritis (LN) is the most common and severe complication of SLE and mechanisms of pathogenesis are not clearly defined and current therapies are toxic and ineffective. We previously reported TNIP1 gene variants as risks for LN. TNIP1 encodes the protein ABIN1, which is a polyubiquitin binding protein that negatively regulates the prominent immune regulatory transcription factor NF-κB. We reported that transgenic mice with impaired ABIN1 ubiquitin binding function (ABIN1[D485N]) spontaneously develop SLE-like autoimmunity and LN and that ABIN1 determines the severity of LN via activation of kidney and immune cell inflammation. Interferon gamma-inducible protein -10 (IP-10) is a pro-inflammatory chemokine and NF-κB target that has been implicated in the pathogenesis and as a diagnostic marker of LN. The current project tested a hypothesis that LN development is mediated by induction of P-10 expression due to loss of cellular ABIN1 ubiquitin binding activity. We found that serum, urine, and kidney cell IP-10 expression is enhanced in ABIN1[D485N] mice. We also found that urinary IP-10 levels are higher in LN patients with TINIP1/ABIN1 variant rs4958881 when compare to LN patients without the TNIP1 variant and healthy controls. Our findings indicate that TNIIP/ABIN1 mutation contributes to the pathogenesis of LN via kidney and immune cell induction of IP-10 secretion and that serum and urinary IP-10 are promising diagnostic markers for LN especially in patients with TNIP1 variants. Further, successful Phase 2 clinical trials with IP-10 mAb for ulcerative colitis indicate its potential for effective LN treatment.
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Caster DJ, Powell DW. Precision Targeting of NF-κB Signaling in Lupus Nephritis. Lupus (Los Angel) 2020; 6:160. [PMID: 35784620 PMCID: PMC9245607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Lupus Nephritis (LN) is the leading cause of morbidity and mortality from Systemic Lupus Erythematosus (SLE) and enhanced activation of the transcription regulator nuclear factor kappa B (NF-κB) is implicated as a central player in the development and progression of LN. SLE and LN are proposed to develop through a "two-hit" process of genetic mutation or variants providing susceptibility to disease provoking molecular events in response to environmental triggers (viral infection, medication, etc.). Many of the susceptibility genes identified in association with LN are involved in NF-κB regulation and loss of function of some of the protein products in animal's results in protection from or development of SLE and LN phenotypes. This short commentary will discuss these factors and implications in precision treatment of LN.
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Caster DJ, Powell DW. Utilization of Biomarkers in Lupus Nephritis. Adv Chronic Kidney Dis 2019; 26:351-359. [PMID: 31733719 DOI: 10.1053/j.ackd.2019.09.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 08/22/2019] [Accepted: 09/06/2019] [Indexed: 12/20/2022]
Abstract
Lupus nephritis (LN) occurs in up to 60% of SLE patients, and is a leading cause of disability and death. Current treatment of LN consists of a combination of high dose corticosteroids that non-specifically decrease inflammation and cytotoxic medications that reduce auto-antibody production. That combination of therapy is associated with significant side effects while remission rates remain inadequate. Since the introduction of biologics into the pharmacological armamentarium, there has been hope for less toxic and more effective therapies for LN. Unfortunately, after multiple clinical trials, no biologic has improved efficacy over standard of care therapies for LN. This is likely, in part, due to disease heterogeneity. The utilization of biomarkers in LN may provide a way to stratify patients and guide therapeutic options. In this review, we summarize traditional and novel LN biomarkers and discuss how they may be used to diagnose, stratify, and guide therapy in patients with LN, bringing precision medicine to the forefront of LN therapy.
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Caster DJ, Merchant ML, Klein JB, Powell DW. Precision medicine in lupus nephritis: can biomarkers get us there? Transl Res 2018; 201:26-39. [PMID: 30179587 PMCID: PMC6415919 DOI: 10.1016/j.trsl.2018.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 08/04/2018] [Accepted: 08/07/2018] [Indexed: 01/08/2023]
Abstract
Patients with systemic lupus erythematosus frequently develop lupus nephritis (LN), a condition that can lead to end-stage kidney disease. Multiple serum and urine biomarkers for LN have been proposed in recent years, yet none have become incorporated into clinical use. The majority of studies have been single center with significant variability in cohorts, assays, and sample storage, leading to inconclusive results. It has become clear that no single biomarker is likely to be sufficient to diagnose LN, identify flares, and define the response to therapy and prognosis. A more likely scenario is a panel of urine, serum, tissue, and genetic biomarkers. In this review, we summarize traditional and novel biomarkers and discuss how they may be utilized in order to bring precision medicine to clinical practice in LN.
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Affiliation(s)
- Dawn J Caster
- Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; Robley Rex Veterans Affairs Medical Center, Louisville, Kentucky.
| | - Michael L Merchant
- Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Jon B Klein
- Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; Robley Rex Veterans Affairs Medical Center, Louisville, Kentucky
| | - David W Powell
- Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
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Caster DJ, Korte EA, Tan M, Barati MT, Tandon S, Creed TM, Salant DJ, Hata JL, Epstein PN, Huang H, Powell DW, McLeish KR. Neutrophil exocytosis induces podocyte cytoskeletal reorganization and proteinuria in experimental glomerulonephritis. Am J Physiol Renal Physiol 2018; 315:F595-F606. [PMID: 29790391 DOI: 10.1152/ajprenal.00039.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Acute glomerulonephritis is characterized by rapid glomerular neutrophil recruitment, proteinuria, and glomerular hypercellularity. The current study tested the hypothesis that the release of neutrophil granule contents plays a role in both the loss of filtration barrier leading to proteinuria and the increase in glomerular cells. Inhibition of neutrophil exocytosis with a peptide inhibitor prevented proteinuria and attenuated podocyte and endothelial cell injury but had no effect on glomerular hypercellularity in an experimental acute glomerulonephritis model in mice. Cultivation of podocytes with neutrophil granule contents disrupted cytoskeletal organization, an in vitro model for podocyte effacement and loss of filtration barrier. Activated, cultured podocytes released cytokines that stimulated neutrophil chemotaxis, primed respiratory burst activity, and stimulated neutrophil exocytosis. We conclude that crosstalk between podocytes and neutrophils contributes to disruption of the glomerular filtration barrier in acute glomerulonephritis. Neutrophil granule products induce podocyte injury but do not participate in the proliferative response of intrinsic glomerular cells.
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Affiliation(s)
- Dawn J Caster
- Department of Medicine, University of Louisville , Louisville, Kentucky.,Robley Rex Veterans Affairs Medical Center , Louisville, Kentucky
| | - Erik A Korte
- Department of Biochemistry and Molecular Genetics, University of Louisville , Louisville, Kentucky
| | - Min Tan
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - Michelle T Barati
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - Shweta Tandon
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - T Michael Creed
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - David J Salant
- Department of Medicine, Boston University School of Medicine , Boston, Massachusetts
| | - Jessica L Hata
- Pathology Department, Norton Children's Hospital , Louisville, Kentucky
| | - Paul N Epstein
- Pediatric Research Institute in the Department of Pediatrics, University of Louisville , Louisville, Kentucky
| | - Hui Huang
- Pediatric Research Institute in the Department of Pediatrics, University of Louisville , Louisville, Kentucky.,Department of Endocrinology, Metabolism, and Genetics, Jiangxi Provincial Children's Hospital , Nanchang , China
| | - David W Powell
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - Kenneth R McLeish
- Department of Medicine, University of Louisville , Louisville, Kentucky.,Robley Rex Veterans Affairs Medical Center , Louisville, Kentucky
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Taylor EB, Barati MT, Powell DW, Turbeville HR, Ryan MJ. Plasma Cell Depletion Attenuates Hypertension in an Experimental Model of Autoimmune Disease. Hypertension 2018; 71:719-728. [PMID: 29378858 DOI: 10.1161/hypertensionaha.117.10473] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 10/26/2017] [Accepted: 01/06/2018] [Indexed: 12/24/2022]
Abstract
Numerous studies show a direct relation between circulating autoantibodies, characteristic of systemic autoimmune disorders, and primary hypertension in humans. Whether these autoantibodies mechanistically contribute to the development of hypertension remains unclear. Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by aberrant immunoglobulin production, notably pathogenic autoantibodies, and is associated with prevalent hypertension, renal injury, and cardiovascular disease. Because plasma cells produce the majority of serum immunoglobulins and are the primary source of autoantibodies in SLE, we hypothesized that plasma cell depletion using the proteasome inhibitor bortezomib would lower autoantibody production and attenuate hypertension. Thirty-week-old female SLE (NZBWF1) and control (NZW [New Zealand White]) mice were injected IV with vehicle (0.9% saline) or bortezomib (0.75 mg/kg) twice weekly for 4 weeks. Bortezomib treatment significantly lowered the percentage of bone marrow plasma cells in SLE mice. Total plasma IgG and anti-dsDNA IgG levels were higher in SLE mice compared with control mice but were lowered by bortezomib treatment. Mean arterial pressure (mm Hg) measured in conscious mice by carotid artery catheter was higher in SLE mice than in control mice, but mean arterial pressure was significantly lower in bortezomib-treated SLE mice. Bortezomib also attenuated renal injury, as assessed by albuminuria and glomerulosclerosis, and reduced glomerular immunoglobulin deposition and B and T lymphocytes infiltration into the kidneys. Taken together, these data show that the production of autoantibodies by plasma cells mechanistically contributes to autoimmune-associated hypertension and suggests a potential role for patients with primary hypertension who have increased circulating immunoglobulins.
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Affiliation(s)
- Erin B Taylor
- From the Department of Physiology and Biophysics (E.B.T., M.J.R.) and Department of Pharmacology & Toxicology (H.R.T.), University of Mississippi Medical Center, Jackson; Department of Medicine, University of Louisville School of Medicine, KY (M.T.B., D.W.P.); and G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, MS (M.J.R.)
| | - Michelle T Barati
- From the Department of Physiology and Biophysics (E.B.T., M.J.R.) and Department of Pharmacology & Toxicology (H.R.T.), University of Mississippi Medical Center, Jackson; Department of Medicine, University of Louisville School of Medicine, KY (M.T.B., D.W.P.); and G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, MS (M.J.R.)
| | - David W Powell
- From the Department of Physiology and Biophysics (E.B.T., M.J.R.) and Department of Pharmacology & Toxicology (H.R.T.), University of Mississippi Medical Center, Jackson; Department of Medicine, University of Louisville School of Medicine, KY (M.T.B., D.W.P.); and G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, MS (M.J.R.)
| | - Hannah R Turbeville
- From the Department of Physiology and Biophysics (E.B.T., M.J.R.) and Department of Pharmacology & Toxicology (H.R.T.), University of Mississippi Medical Center, Jackson; Department of Medicine, University of Louisville School of Medicine, KY (M.T.B., D.W.P.); and G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, MS (M.J.R.)
| | - Michael J Ryan
- From the Department of Physiology and Biophysics (E.B.T., M.J.R.) and Department of Pharmacology & Toxicology (H.R.T.), University of Mississippi Medical Center, Jackson; Department of Medicine, University of Louisville School of Medicine, KY (M.T.B., D.W.P.); and G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, MS (M.J.R.).
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Korte EA, Caster DJ, Barati MT, Tan M, Zheng S, Berthier CC, Brosius FC, Vieyra MB, Sheehan RM, Kosiewicz M, Wysoczynski M, Gaffney PM, Salant DJ, McLeish KR, Powell DW. ABIN1 Determines Severity of Glomerulonephritis via Activation of Intrinsic Glomerular Inflammation. Am J Pathol 2017; 187:2799-2810. [PMID: 28935578 PMCID: PMC5718094 DOI: 10.1016/j.ajpath.2017.08.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 07/15/2017] [Accepted: 08/17/2017] [Indexed: 10/24/2022]
Abstract
Transcription factor NF-κB regulates expression of numerous genes that control inflammation and is activated in glomerular cells in glomerulonephritis (GN). We previously identified genetic variants for a NF-κB regulatory, ubiquitin-binding protein ABIN1 as risk factors for GN in systemic autoimmunity. The goal was to define glomerular inflammatory events controlled by ABIN1 function in GN. Nephrotoxic serum nephritis was induced in wild-type (WT) and ubiquitin-binding deficient ABIN1[D485N] mice, and renal pathophysiology and glomerular inflammatory phenotypes were assessed. Proteinuria was also measured in ABIN1[D485N] mice transplanted with WT mouse bone marrow. Inflammatory activation of ABIN1[D472N] (D485N homolog) cultured human-derived podocytes, and interaction with primary human neutrophils were also assessed. Disruption of ABIN1 function exacerbated proteinuria, podocyte injury, glomerular NF-κB activity, glomerular expression of inflammatory mediators, and glomerular recruitment and retention of neutrophils in antibody-mediated nephritis. Transplantation of WT bone marrow did not prevent the increased proteinuria in ABIN1[D845N] mice. Tumor necrosis factor-stimulated enhanced expression and secretion of NF-κB-targeted proinflammatory mediators in ABIN1[D472N] cultured podocytes compared with WT cells. Supernatants from ABIN1[D472N] podocytes accelerated chemotaxis of human neutrophils, and ABIN1[D472N] podocytes displayed a greater susceptibility to injurious morphologic findings induced by neutrophil granule contents. These studies define a novel role for ABIN1 dysfunction and NF-κB in mediating GN through proinflammatory activation of podocytes.
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Affiliation(s)
- Erik A Korte
- Department of Medicine University of Louisville, Louisville, Kentucky
| | - Dawn J Caster
- Department of Medicine University of Louisville, Louisville, Kentucky; Robley Rex VA Medical Center, Louisville, Kentucky
| | - Michelle T Barati
- Department of Medicine University of Louisville, Louisville, Kentucky
| | - Min Tan
- Department of Medicine University of Louisville, Louisville, Kentucky
| | - Shirong Zheng
- Department of Medicine University of Louisville, Louisville, Kentucky
| | - Celine C Berthier
- Department of Internal Medicine-Nephrology, University of Michigan, Ann Arbor, Michigan
| | - Frank C Brosius
- Department of Internal Medicine-Nephrology, University of Michigan, Ann Arbor, Michigan
| | - Mark B Vieyra
- Department of Medicine University of Louisville, Louisville, Kentucky
| | - Ryan M Sheehan
- Department of Medicine University of Louisville, Louisville, Kentucky
| | - Michele Kosiewicz
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky
| | | | - Patrick M Gaffney
- Arthritis and Clinical Immunology Program and Clinical Pharmacology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - David J Salant
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
| | - Kenneth R McLeish
- Department of Medicine University of Louisville, Louisville, Kentucky; Department of Internal Medicine-Nephrology, University of Michigan, Ann Arbor, Michigan
| | - David W Powell
- Department of Medicine University of Louisville, Louisville, Kentucky.
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Abstract
Significant advances in understanding the pathogenesis of GN have occurred in recent decades. Among those advances is the finding that both innate and adaptive immune cells contribute to the development of GN. Neutrophils were recognized as key contributors in early animal models of GN, at a time when the prevailing view considered neutrophils to function as nonspecific effector cells that die quickly after performing antimicrobial functions. However, advances over the past two decades have shown that neutrophil functions are more complex and sophisticated. Specifically, research has revealed that neutrophil survival is regulated by the inflammatory milieu and that neutrophils demonstrate plasticity, mediate microbial killing through previously unrecognized mechanisms, demonstrate transcriptional activity leading to the release of cytokines and chemokines, interact with and regulate cells of the innate and adaptive immune systems, and contribute to the resolution of inflammation. Therefore, neutrophil participation in glomerular diseases deserves re-evaluation. In this review, we describe advances in understanding classic neutrophil functions, review the expanded roles of neutrophils in innate and adaptive immune responses, and summarize current knowledge of neutrophil contributions to GN.
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Affiliation(s)
- Dawn J Caster
- Division of Nephrology and Hypertension, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky, .,Nephrology Section, Medicine Service, Robley Rex Veterans Affairs Medical Center, Louisville, Kentucky, and
| | - David W Powell
- Division of Nephrology and Hypertension, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Irina Miralda
- Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, Kentucky
| | - Richard A Ward
- Division of Nephrology and Hypertension, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Kenneth R McLeish
- Division of Nephrology and Hypertension, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky.,Nephrology Section, Medicine Service, Robley Rex Veterans Affairs Medical Center, Louisville, Kentucky, and
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13
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Shi XZ, Winston JH, Powell DW, Otterson M, Shaker R. Obituary. Neurogastroenterol Motil 2017; 29. [PMID: 28345806 DOI: 10.1111/nmo.13079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- X-Z Shi
- University of Texas Medical Branch, Galveston, TX, USA
| | - J H Winston
- University of Texas Medical Branch, Galveston, TX, USA
| | - D W Powell
- University of Texas Medical Branch, Galveston, TX, USA
| | - M Otterson
- Medical College of Wisconsin, Milwaukee, WI, USA
| | - R Shaker
- Medical College of Wisconsin, Milwaukee, WI, USA
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14
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Powell DW, McLeish KR, Tan M, Sheehan RM, Zheng S, Caster DJ, Korte EA. A novel mechanism for enhanced neutrophil recruitment, retention, and podocyte damage in immune complex-mediated glomerular disease. The Journal of Immunology 2016. [DOI: 10.4049/jimmunol.196.supp.124.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Glomerulonephritis (GN) is characterized by immune complex deposition and ensuing inflammation within the glomerulus of the kidney. Frank J. Dixon, a pioneer in immunologic kidney disease research, reported in 1965 that injection of nephrotoxic antibodies in rats and rabbits resulted in proteinuria and glomerular accumulation of neutrophils, and that depletion of circulating neutrophils reduced this immune-mediated glomerular damage and proteinuria. In the decades since, studies have confirmed a role for glomerular neutrophil accumulation in human GN, but the mechanisms for neutrophil recruitment and neutrophil-directed injury have not been resolved. We previously reported genetic variants for a NF-κB inhibitor ABIN1 as risks for GN. Others also report that glomerular ABIN1 gene expression is altered in GN in mice and humans. Here we present that transgenic disruption of ABIN1 function results in exacerbated podocyte injury, glomerular expression of inflammatory mediators, and glomerular recruitment and retention of neutrophils in a mouse model of acute antibody-mediated GN. Moreover, a novel inhibitor of neutrophil granule release (SNAP23 peptide) also attenuates podocyte injury in this model. These in vivo findings are supported by in vitro experiments showing that secretome from homologous ABIN1 mutant podocytes activates neutrophil chemotaxis and granule release and neutrophil granule contents specifically disrupts cytoskeletal organization of ABIN1 mutant podocytes. These studies unfold a role for ABIN1 dysfunction in a novel neutrophil-mediated mechanism of podocyte injury in GN and presents inhibition of neutrophil granule release as a promising novel therapeutic direction for kidney inflammation.
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15
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Zheng S, Powell DW, Zheng F, Kantharidis P, Gnudi L. Diabetic Nephropathy: Proteinuria, Inflammation, and Fibrosis. J Diabetes Res 2016; 2016:5241549. [PMID: 26881250 PMCID: PMC4736592 DOI: 10.1155/2016/5241549] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 12/17/2015] [Indexed: 11/25/2022] Open
Affiliation(s)
- Shirong Zheng
- Department of Cardiovascular and Thoracic Surgery, Cardiovascular Innovation Institute, University of Louisville, Louisville, KY 40202, USA
- *Shirong Zheng:
| | - David W. Powell
- Department of Medicine and Division of Nephrology and Hypertension, School of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Feng Zheng
- Department of Nephrology, The Second Hospital and Advanced Institute for Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Phillip Kantharidis
- JDRF Danielle Alberti Memorial Centre for Diabetes Complications, Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Luigi Gnudi
- Cardiovascular Division, School of Life Science & Medicine, King's College London, Department of Diabetes and Endocrinology, Guy's Hospital, London SE1 9RT, UK
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16
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Zheng S, Coventry S, Cai L, Powell DW, Jala VR, Haribabu B, Epstein PN. Renal Protection by Genetic Deletion of the Atypical Chemokine Receptor ACKR2 in Diabetic OVE Mice. J Diabetes Res 2016; 2016:5362506. [PMID: 26798651 PMCID: PMC4699014 DOI: 10.1155/2016/5362506] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 09/25/2015] [Accepted: 09/27/2015] [Indexed: 11/29/2022] Open
Abstract
In diabetic nephropathy (DN) proinflammatory chemokines and leukocyte infiltration correlate with tubulointerstitial injury and declining renal function. The atypical chemokine receptor ACKR2 is a chemokine scavenger receptor which binds and sequesters many inflammatory CC chemokines but does not transduce typical G-protein mediated signaling events. ACKR2 is known to regulate diverse inflammatory diseases but its role in DN has not been tested. In this study, we utilized ACKR2(-/-) mice to test whether ACKR2 elimination alters progression of diabetic kidney disease. Elimination of ACKR2 greatly reduced DN in OVE26 mice, an established DN model. Albuminuria was significantly lower at 2, 4, and 6 months of age. ACKR2 deletion did not affect diabetic blood glucose levels but significantly decreased parameters of renal inflammation including leukocyte infiltration and fibrosis. Activation of pathways that increase inflammatory gene expression was attenuated. Human biopsies stained with ACKR2 antibody revealed increased staining in diabetic kidney, especially in some tubule and interstitial cells. The results demonstrate a significant interaction between diabetes and ACKR2 protein in the kidney. Unexpectedly, ACKR2 deletion reduced renal inflammation in diabetes and the ultimate response was a high degree of protection from diabetic nephropathy.
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Affiliation(s)
- Shirong Zheng
- Department of Pediatrics, University of Louisville, Louisville, KY 40202, USA
- *Shirong Zheng:
| | - Susan Coventry
- Department of Pathology, University of Louisville, Louisville, KY 40202, USA
| | - Lu Cai
- Department of Pediatrics, University of Louisville, Louisville, KY 40202, USA
| | - David W. Powell
- Department of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Venkatakrishna R. Jala
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY 40202, USA
| | - Bodduluri Haribabu
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY 40202, USA
| | - Paul N. Epstein
- Department of Pediatrics, University of Louisville, Louisville, KY 40202, USA
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17
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Barati MT, Powell DW, Kechavarzi BD, Isaacs SM, Zheng S, Epstein PN, Cai L, Coventry S, Rane MJ, Klein JB. Differential expression of endoplasmic reticulum stress-response proteins in different renal tubule subtypes of OVE26 diabetic mice. Cell Stress Chaperones 2016; 21:155-166. [PMID: 26483256 PMCID: PMC4679738 DOI: 10.1007/s12192-015-0648-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 09/28/2015] [Accepted: 10/01/2015] [Indexed: 02/01/2023] Open
Abstract
Regulation of the endoplasmic reticulum (ER) stress-response pathway during the course of diabetes specifically in renal tubules is unclear. Since tubule cell dysfunction is critical to progression of diabetic nephropathy, this study analyzed markers of ER stress response and ER chaperones at different stages of diabetes and in different renal tubule subtypes of OVE26 type-1 diabetic mice. ER stress-responseinduced chaperones GRP78, GRP94, and protein disulfide isomerase (PDI) were increased in isolated cortical tubules of older diabetic mice, while PDI was decreased in tubules of young diabetic mice. Immunofluorescence staining of kidneys from older mice showed GRP78 and PDI upregulation in all cortical tubule segments, with substantial induction of PDI in distal tubules. Protein kinase RNA-like endoplasmic reticulum kinase (PERK) phosphorylation was increased in cortical tubules of young diabetic mice, with no differences between older diabetic and control mice. Expression of ER stress-induced PERK inhibitor p58IPK was decreased and then increased in all tubule subtypes of young and older mice, respectively. Knockdown of PERK by small interfering RNA (siRNA) increased fibronectin secretion in cultured proximal tubule cells. Tubules of older diabetic mice had significantly more apoptotic cells, and ER stress-induced proapoptotic transcription factor C/EBP homologous protein (CHOP) was increased in proximal and distal tubules of diabetic mice and diabetic humans. CHOP induction in OVE26 mice was not altered by severity of proteinuria. Overexpression of CHOP in cultured proximal tubule cells increased expression of fibronectin. These findings demonstrate differential ER stress-response signaling in tubule subtypes of diabetic mice and implicate a role for PERK and CHOP in tubule cell matrix protein production.
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Affiliation(s)
- Michelle T Barati
- Kidney Disease Program, Department of Medicine, University of Louisville, 570 S. Preston St., Room 102, Louisville, KY, 40202, USA.
| | - David W Powell
- Kidney Disease Program, Department of Medicine, University of Louisville, 570 S. Preston St., Room 102, Louisville, KY, 40202, USA
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY, USA
| | - Bobak D Kechavarzi
- Kidney Disease Program, Department of Medicine, University of Louisville, 570 S. Preston St., Room 102, Louisville, KY, 40202, USA
| | - Susan M Isaacs
- Kidney Disease Program, Department of Medicine, University of Louisville, 570 S. Preston St., Room 102, Louisville, KY, 40202, USA
| | - Shirong Zheng
- Department of Pediatrics, University of Louisville, Louisville, KY, USA
| | - Paul N Epstein
- Department of Pediatrics, University of Louisville, Louisville, KY, USA
| | - Lu Cai
- Department of Pediatrics, University of Louisville, Louisville, KY, USA
| | - Susan Coventry
- Department of Pediatric Pathology, University of Louisville, Louisville, KY, USA
| | - Madhavi J Rane
- Kidney Disease Program, Department of Medicine, University of Louisville, 570 S. Preston St., Room 102, Louisville, KY, 40202, USA
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY, USA
| | - Jon B Klein
- Kidney Disease Program, Department of Medicine, University of Louisville, 570 S. Preston St., Room 102, Louisville, KY, 40202, USA
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY, USA
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18
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G'Sell RT, Gaffney PM, Powell DW. A20-Binding Inhibitor of NF-κB Activation 1 is a Physiologic Inhibitor of NF-κB: A Molecular Switch for Inflammation and Autoimmunity. Arthritis Rheumatol 2015; 67:2292-302. [PMID: 26097105 DOI: 10.1002/art.39245] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 06/09/2015] [Indexed: 01/24/2023]
Affiliation(s)
- Rachel T G'Sell
- University of Louisville School of Medicine, Louisville, Kentucky
| | | | - David W Powell
- University of Louisville School of Medicine, Louisville, Kentucky
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19
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Caster DJ, Hobeika L, Klein JB, Powell DW, McLeish KR. Changing the concepts of immune-mediated glomerular diseases through proteomics. Proteomics Clin Appl 2015; 9:967-71. [PMID: 25907758 DOI: 10.1002/prca.201400159] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 02/01/2015] [Accepted: 04/21/2015] [Indexed: 01/27/2023]
Abstract
Standard classification of glomerular diseases is based on histopathologic abnormalities. The recent application of proteomic technologies has resulted in paradigm changes in the understanding and classification of idiopathic membranous nephropathy and membranoproliferative glomerulonephritis. Those examples provide evidence that proteomics will lead to advances in understanding of the molecular basis of other glomerular diseases, such as lupus nephritis. Proof of principle experiments show that proteomics can be applied to patient renal biopsy specimens. This viewpoint summarizes the advances in immune-mediated glomerular diseases that have relied on proteomics, and potential future applications are discussed.
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Affiliation(s)
- Dawn J Caster
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA.,Robley Rex VA Medical Center, Louisville, KY, USA
| | - Liliane Hobeika
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA
| | - Jon B Klein
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA.,Robley Rex VA Medical Center, Louisville, KY, USA
| | - David W Powell
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA
| | - Kenneth R McLeish
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA.,Robley Rex VA Medical Center, Louisville, KY, USA
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20
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Caster DJ, Korte EA, Merchant ML, Klein JB, Wilkey DW, Rovin BH, Birmingham DJ, Harley JB, Cobb BL, Namjou B, McLeish KR, Powell DW. Autoantibodies targeting glomerular annexin A2 identify patients with proliferative lupus nephritis. Proteomics Clin Appl 2015; 9:1012-20. [PMID: 25824007 DOI: 10.1002/prca.201400175] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 02/10/2015] [Accepted: 03/26/2015] [Indexed: 11/09/2022]
Abstract
PURPOSE Patients with systemic lupus erythematosus (SLE) frequently develop lupus nephritis (LN), a complication frequently leading to end stage kidney disease. Immune complex deposition in the glomerulus is central to the development of LN. Using a targeted proteomic approach, we tested the hypothesis that autoantibodies targeting glomerular antigens contribute to the development of LN. EXPERIMENTAL DESIGN Human podocyte and glomerular proteins were separated by SDS-PAGE and immunoblotted with sera from SLE patients with and without LN. The regions of those gels corresponding to reactive bands observed with sera from LN patients were analyzed using LC-MS/MS. RESULTS LN reactive bands were seen at approximately 50 kDa in podocyte extracts and between 36 and 50 kDa in glomerular extracts. Those bands were analyzed by LC-MS/MS and 102 overlapping proteins were identified. Bioinformatic analysis determined that 36 of those proteins were membrane associated, including a protein previously suggested to contribute to glomerulonephritis and LN, annexin A2. By ELISA, patients with proliferative LN demonstrated significantly increased antibodies against annexin A2. CONCLUSION AND CLINICAL RELEVANCE Proteomic approaches identified multiple candidate antigens for autoantibodies in patients with LN. Serum antibodies against annexin A2 were significantly elevated in subjects with proliferative LN, validating those antibodies as potential biomarkers.
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Affiliation(s)
- Dawn J Caster
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA.,Robley Rex Veterans Affairs Medical Center, Louisville, KY, USA
| | - Erik A Korte
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY, USA
| | - Michael L Merchant
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA
| | - Jon B Klein
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA.,Robley Rex Veterans Affairs Medical Center, Louisville, KY, USA
| | - Daniel W Wilkey
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA
| | - Brad H Rovin
- Department of Medicine, the Ohio State University, Columbus, OH, USA
| | - Dan J Birmingham
- Department of Medicine, the Ohio State University, Columbus, OH, USA
| | - John B Harley
- Center for Autoimmune Genomics and Etiology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center and the University of Cincinnati, Cincinnati, OH, USA.,US Department of Veterans Affairs Medical Center, Cincinnati, OH, USA
| | - Beth L Cobb
- Center for Autoimmune Genomics and Etiology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center and the University of Cincinnati, Cincinnati, OH, USA
| | - Bahram Namjou
- Center for Autoimmune Genomics and Etiology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center and the University of Cincinnati, Cincinnati, OH, USA
| | - Kenneth R McLeish
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA.,Robley Rex Veterans Affairs Medical Center, Louisville, KY, USA
| | - David W Powell
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA.,Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY, USA
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21
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Xu X, Powell DW, Lambring CJ, Puckett AH, Deschenes L, Prough RA, Poeschla EM, Samuelson DJ. Human MCS5A1 candidate breast cancer susceptibility gene FBXO10 is induced by cellular stress and correlated with lens epithelium-derived growth factor (LEDGF). Mol Carcinog 2014; 53:300-13. [PMID: 23138933 PMCID: PMC9737042 DOI: 10.1002/mc.21977] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 10/04/2012] [Accepted: 10/12/2012] [Indexed: 12/14/2022]
Abstract
Genetic variation and candidate genes associated with breast cancer susceptibility have been identified. Identifying molecular interactions between associated genetic variation and cellular proteins may help to better understand environmental risk. Human MCS5A1 breast cancer susceptibility associated SNP rs7042509 is located in F-box protein 10 (FBXO10). An orthologous Rattus norvegicus DNA-sequence that contains SNV ss262858675 is located in rat Mcs5a1, which is part of a mammary carcinoma susceptibility locus controlling tumor development in a non-mammary cell-autonomous manner via an immune cell-mediated mechanism. Higher Fbxo10 expression in T cells is associated with Mcs5a increased susceptibility alleles. A common DNA-protein complex bound human and rat sequences containing MCS5A1/Mcs5a1 rs7042509/ss262858675 in electrophoretic mobility shift assays (EMSAs). Lens epithelium-derived growth factor (LEDGF), a stress-response protein, was identified as a candidate to bind both human and rat sequences using DNA-pulldown and mass spectrometry. LEDGF binding was confirmed by LEDGF-antibody EMSA and chromatin immunoprecipitation (ChIP). Ectopic expression of LEDGF/p75 increased luciferase activities of co-transfected reporters containing both human and rat orthologs. Over-expressed LEDGF/p75 increased endogenous FBXO10 mRNA levels in Jurkat cells, a human T-cell line, implying LEDGF may be involved in increasing FBXO10 transcript levels. Oxidative and thermal stress of Jurkat cells increased FBXO10 and LEDGF expression, further supporting a hypothesis that LEDGF binds to a regulatory region of FBXO10 and increases expression during conditions favoring carcinogenesis. We conclude that FBXO10, a candidate breast cancer susceptibility associated gene, is induced by cellular stress and LEDGF may play a role in expression of this gene.
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Affiliation(s)
- Xin Xu
- Department of Biochemistry and Molecular Biology, University of Louisville Health Sciences Center, Louisville, Kentucky
| | - David W. Powell
- Department of Biochemistry and Molecular Biology, University of Louisville Health Sciences Center, Louisville, Kentucky,Department of Medicine/Nephrology, University of Louisville Health Sciences Center, Louisville, Kentucky
| | - Courtney J. Lambring
- Department of Biochemistry and Molecular Biology, University of Louisville Health Sciences Center, Louisville, Kentucky
| | - Aaron H. Puckett
- Department of Biochemistry and Molecular Biology, University of Louisville Health Sciences Center, Louisville, Kentucky
| | - Lucas Deschenes
- Department of Biochemistry and Molecular Biology, University of Louisville Health Sciences Center, Louisville, Kentucky
| | - Russell A. Prough
- Department of Biochemistry and Molecular Biology, University of Louisville Health Sciences Center, Louisville, Kentucky,Center for Environmental Genomics and Integrative Biology, University of Louisville, Louisville, Kentucky
| | - Eric M. Poeschla
- Department of Molecular Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - David J. Samuelson
- Department of Biochemistry and Molecular Biology, University of Louisville Health Sciences Center, Louisville, Kentucky,Center for Environmental Genomics and Integrative Biology, University of Louisville, Louisville, Kentucky,Correspondence to: Department of Biochemistry & Molecular Biology, Center for Genetics & Molecular Medicine, University of Louisville, School of Medicine, HSC-A Building, Room 708, 319 Abraham Flexner Way, Louisville, KY 40292
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22
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Caster DJ, Korte EA, Nanda SK, McLeish KR, Oliver RK, G'sell RT, Sheehan RM, Freeman DW, Coventry SC, Kelly JA, Guthridge JM, James JA, Sivils KL, Alarcon-Riquelme ME, Scofield RH, Adrianto I, Gaffney PM, Stevens AM, Freedman BI, Langefeld CD, Tsao BP, Pons-Estel BA, Jacob CO, Kamen DL, Gilkeson GS, Brown EE, Alarcon GS, Edberg JC, Kimberly RP, Martin J, Merrill JT, Harley JB, Kaufman KM, Reveille JD, Anaya JM, Criswell LA, Vila LM, Petri M, Ramsey-Goldman R, Bae SC, Boackle SA, Vyse TJ, Niewold TB, Cohen P, Powell DW. ABIN1 dysfunction as a genetic basis for lupus nephritis. J Am Soc Nephrol 2013; 24:1743-54. [PMID: 23970121 DOI: 10.1681/asn.2013020148] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The genetic factors underlying the pathogenesis of lupus nephritis associated with systemic lupus erythematosus are largely unknown, although animal studies indicate that nuclear factor (NF)-κB is involved. We reported previously that a knockin mouse expressing an inactive form of ABIN1 (ABIN1[D485N]) develops lupus-like autoimmune disease and demonstrates enhanced activation of NF-κB and mitogen-activated protein kinases in immune cells after toll-like receptor stimulation. In the current study, we show that ABIN1[D485N] mice develop progressive GN similar to class III and IV lupus nephritis in humans. To investigate the clinical relevance of ABIN1 dysfunction, we genotyped five single-nucleotide polymorphisms in the gene encoding ABIN1, TNIP1, in samples from European-American, African American, Asian, Gullah, and Hispanic participants in the Large Lupus Association Study 2. Comparing cases of systemic lupus erythematosus with nephritis and cases of systemic lupus erythematosus without nephritis revealed strong associations with lupus nephritis at rs7708392 in European Americans and rs4958881 in African Americans. Comparing cases of systemic lupus erythematosus with nephritis and healthy controls revealed a stronger association at rs7708392 in European Americans but not at rs4958881 in African Americans. Our data suggest that variants in the TNIP1 gene are associated with the risk for lupus nephritis and could be mechanistically involved in disease development via aberrant regulation of NF-κB and mitogen-activated protein kinase activity.
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23
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Kruer TL, Cummins TD, Powell DW, Wittliff JL. Characterization of estrogen response element binding proteins as biomarkers of breast cancer behavior. Clin Biochem 2013; 46:1739-46. [PMID: 23868020 DOI: 10.1016/j.clinbiochem.2013.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 06/27/2013] [Accepted: 07/01/2013] [Indexed: 12/30/2022]
Abstract
BACKGROUND While investigating estrogen response element (ERE) binding properties of human estrogen receptor-α (hERα) in breast cancer cytosols, other ERE-binding proteins (ERE-BP) were observed. DESIGN AND METHODS Recognition properties of ERE-BP were evaluated by electrophoretic mobility shift assays (EMSA) with ERE sequences of the 5'-flanking region of the estrogen responsive gene vitellogenin A2 (VitA2). Cytosols were incubated 16 h, 4 °C with [32P]ERE sequences and separated by EMSA. A method of estimating ERE-BP levels was developed by measuring band intensity from EMSA profiles, expressed in digital light units (DLU)/μg protein and normalized to total DLU. ERE-BP were purified by affinity chromatography and EMSA, and then identified by mass spectrometry. RESULTS ERE-BP in cytosols did not supershift in the presence of anti-hERα or anti-hERβ antibodies recognizing different ER epitopes suggesting that they are not fragments of either receptor isoform. ERE-BP competed with hERα for binding to VitA2-ERE. Increased levels of ERE-BP DNA-binding activities measured in 310 cytosols prepared from breast cancer biopsies correlated with decreased patient survival. Strikingly, breast cancer patients with ER negative status and high ERE-BP expression exhibited the poorest disease-free and overall survival. After purification, ERE-BP were identified as Ku70 (XRCC6) and Ku80 (XRCC5) using mass spectrometry. ERE-BP were confirmed to be Ku70/80 by supershift assay. CONCLUSION Presence of these novel ERE-binding proteins in a breast carcinoma is a strong predictor of poor prognosis. Our results suggest that ERE-BP, identified as Ku70/Ku80, in cytosols prepared from breast carcinoma biopsies are useful biomarkers for assessing risk of breast cancer recurrence.
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Affiliation(s)
- Traci L Kruer
- Hormone Receptor Laboratory, Department of Biochemistry & Molecular Biology, Brown Cancer Center, University of Louisville, Louisville, KY 40292, USA; Institute for Molecular Diversity & Drug Design, University of Louisville, Louisville, KY 40292, USA
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24
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Powell DW, Kenagy DN, Zheng S, Coventry SC, Xu J, Cai L, Carlson EC, Epstein PN. Associations between structural and functional changes to the kidney in diabetic humans and mice. Life Sci 2013; 93:257-64. [PMID: 23800643 DOI: 10.1016/j.lfs.2013.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/09/2013] [Accepted: 06/12/2013] [Indexed: 02/06/2023]
Abstract
Type 1 and Type 2 diabetic patients are at high risk of developing diabetic nephropathy (DN). Renal functional decline is gradual and there is high variability between patients, though the reason for the variability is unknown. Enough diabetic patients progress to end stage renal disease to make diabetes the leading cause of renal failure. The first symptoms of DN do not appear for years or decades after the onset of diabetes. During and after the asymptomatic period structural changes develop in the diabetic kidney. Typically, but not always, the first symptom of DN is albuminuria. Loss of renal filtration rate develops later. This review examines the structural abnormalities of diabetic kidneys that are associated with and possibly the basis for advancing albuminuria and declining GFR. Mouse models of diabetes and genetic manipulations of these models have become central to research into mechanisms underlying DN. This article also looks at the value of these mouse models to understanding human DN as well as potential pitfalls in translating the mouse results to humans.
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Affiliation(s)
- David W Powell
- Department of Medicine, University of Louisville, Louisville, KY, USA
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25
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Tezel G, Thornton IL, Tong MG, Luo C, Yang X, Cai J, Powell DW, Soltau JB, Liebmann JM, Ritch R. Immunoproteomic analysis of potential serum biomarker candidates in human glaucoma. Invest Ophthalmol Vis Sci 2012; 53:8222-31. [PMID: 23150628 DOI: 10.1167/iovs.12-10076] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Evidence supporting the immune system involvement in glaucoma includes increased titers of serum antibodies to retina and optic nerve proteins, although their pathogenic importance remains unclear. This study using an antibody-based proteomics approach aimed to identify disease-related antigens as candidate biomarkers of glaucoma. METHODS Serum samples were collected from 111 patients with primary open-angle glaucoma and an age-matched control group of 49 healthy subjects without glaucoma. For high-throughput characterization of antigens, serum IgG was eluted from five randomly selected glaucomatous samples and analyzed by linear ion trap mass spectrometry (LC-MS/MS). Serum titers of selected biomarker candidates were then measured by specific ELISAs in the whole sample pool (including an additional control group of diabetic retinopathy). RESULTS LC-MS/MS analysis of IgG elutes revealed a complex panel of proteins, including those detectable only in glaucomatous samples. Interestingly, many of these antigens corresponded to upregulated retinal proteins previously identified in glaucomatous donors (or that exhibited increased methionine oxidation). Moreover, additional analysis detected a greater immunoreactivity of the patient sera to glaucomatous retinal proteins (or to oxidatively stressed cell culture proteins), thereby suggesting the importance of disease-related protein modifications in autoantibody production/reactivity. As a narrowing-down strategy for selection of initial biomarker candidates, we determined the serum proteins overlapping with the retinal proteins known to be up-regulated in glaucoma. Four of the selected 10 candidates (AIF, cyclic AMP-responsive element binding protein, ephrin type-A receptor, and huntingtin) exhibited higher ELISA titers in the glaucomatous sera. CONCLUSIONS A number of serum proteins identified by this immunoproteomic study of human glaucoma may represent diseased tissue-related antigens and serve as candidate biomarkers of glaucoma.
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Affiliation(s)
- Gülgün Tezel
- Department of Ophthalmology & Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.
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Tezel G, Yang X, Luo C, Cai J, Powell DW. An astrocyte-specific proteomic approach to inflammatory responses in experimental rat glaucoma. Invest Ophthalmol Vis Sci 2012; 53:4220-33. [PMID: 22570341 DOI: 10.1167/iovs.11-9101] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To delineate astrocyte-mediated inflammatory processes in glaucoma, we analyzed proteomic responses of retinal astrocytes in an experimental rat model using a cell-specific approach. METHODS IOP elevation was induced in rats by hypertonic saline injections into episcleral veins. Enriched samples of astrocytes were isolated through the immunomagnetic cell selection process established originally for retinal ganglion cell (RGC) sampling. Ocular hypertensive and control samples were collected by pooling from rat eyes matched for the cumulative IOP exposure. Protein expression was analyzed complementarily by quantitative two-dimensional capillary liquid chromatography and linear ion trap mass spectrometry (LC-MS/MS) followed by quantitative Western blot analysis and retinal tissue immunolabeling using specific antibodies to selected proteins. RESULTS Following validation of enriched astrocyte samples, LC-MS/MS analysis resulted in the identification of over 2000 proteins with high confidence. Bioinformatic comparison analysis of the high-throughput MS/MS data along with the findings of immunoblotting and immunohistochemistry supported distinct responses of ocular hypertensive astrocytes during the experimental paradigm, which exhibited predominantly cellular activation and immune/inflammatory responses as opposed to activation of cell death signaling in ocular hypertensive RGCs. Inflammatory responses of astrocytes in experimental glaucoma included up-regulation of a number of immune mediators/regulators linked to TNF-α/TNFR signaling, nuclear factor kappa-B (NF-κB) activation, autophagy regulation, and inflammasome assembly. CONCLUSIONS These findings validate an astrocyte-specific approach to quantitatively identify proteomic alterations in experimental glaucoma, and highlight many immune mediators/regulators characteristic of the inflammatory responses of ocular hypertensive astrocytes. By dissecting the complexity of prior data obtained from whole tissue, this pioneering approach should enable astrocyte responses to be defined and new treatments targeting astrocytes to be developed.
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Affiliation(s)
- Gülgün Tezel
- Department of Ophthalmology & Visual Sciences, University of Louisville School of Medicine, Louisville, KY 40202, USA.
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Korte EA, Gaffney PM, Powell DW. Contributions of mass spectrometry-based proteomics to defining cellular mechanisms and diagnostic markers for systemic lupus erythematosus. Arthritis Res Ther 2012; 14:204. [PMID: 22364570 PMCID: PMC3392812 DOI: 10.1186/ar3701] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Systematic lupus erythematosus (SLE) is a complex disease for which molecular diagnostics are limited and pathogenesis is not clearly understood. Important information is provided in this regard by identification and characterization of more specific molecular and cellular targets in SLE immune cells and target tissue and markers of early-onset and effective response to treatment of SLE complications. In recent years, advances in proteomic technologies and applications have facilitated such discoveries. Here we provide a review of insights into SLE pathogenesis, diagnosis and treatment that have been provided by mass spectrometry-based proteomic approaches.
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Affiliation(s)
- Erik A Korte
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, 570 South Preston St, Baxter Research Building I, Room 204E, Louisville, KY 40202, USA
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Donninger H, Barnoud T, Nelson N, Kassler S, Clark J, Cummins TD, Powell DW, Nyante S, Millikan RC, Clark GJ. RASSF1A and the rs2073498 Cancer Associated SNP. Front Oncol 2011; 1:54. [PMID: 22649770 PMCID: PMC3355887 DOI: 10.3389/fonc.2011.00054] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 12/06/2011] [Indexed: 12/23/2022] Open
Abstract
RASSF1A is one of the most frequently inactivated tumor suppressors yet identified in human cancer. It is pro-apoptotic and appears to function as a scaffolding protein that interacts with a variety of other tumor suppressors to modulate their function. It can also complex with the Ras oncoprotein and may serve to integrate pro-growth and pro-death signaling pathways. A SNP has been identified that is present in approximately 29% of European populations [rs2073498, A(133)S]. Several studies have now presented evidence that this SNP is associated with an enhanced risk of developing breast cancer. We have used a proteomics based approach to identify multiple differences in the pattern of protein/protein interactions mediated by the wild type compared to the SNP variant protein. We have also identified a significant difference in biological activity between wild type and SNP variant protein. However, we have found only a very modest association of the SNP with breast cancer predisposition.
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Affiliation(s)
- Howard Donninger
- Molecular Targets Program, Department of Medicine, James Graham Brown Cancer Center, University of Louisville Louisville, KY, USA
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Yang X, Luo C, Cai J, Powell DW, Yu D, Kuehn MH, Tezel G. Neurodegenerative and inflammatory pathway components linked to TNF-α/TNFR1 signaling in the glaucomatous human retina. Invest Ophthalmol Vis Sci 2011; 52:8442-54. [PMID: 21917936 DOI: 10.1167/iovs.11-8152] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE This study aimed to determine retinal proteomic alterations in human glaucoma, with particular focus on links to TNF-α/TNFR1 signaling. METHODS Human retinal protein samples were obtained from 20 donors with (n = 10) or without (n = 10) glaucoma. Alterations in protein expression were individually analyzed by quantitative LC-MS/MS. Quantitative Western blot analysis with cleavage or phosphorylation site-specific antibodies was used for data validation, and cellular localization of selected proteins was determined by immunohistochemical analysis of the retina in an additional group of glaucomatous human donor eyes (n = 38) and nonglaucomatous controls (n = 30). RESULTS Upregulated retinal proteins in human glaucoma included a number of downstream adaptor/interacting proteins and protein kinases involved in TNF-α/TNFR1 signaling. Bioinformatic analysis of the high-throughput data established extended networks of diverse functional interactions with death-promoting and survival-promoting pathways and mediation of immune response. Upregulated pathways included death receptor-mediated caspase cascade, mitochondrial dysfunction, endoplasmic reticulum stress, calpains leading to apoptotic cell death, NF-κB and JAK/STAT pathways, and inflammasome-assembly mediating inflammation. Interestingly, retinal expression pattern of a regulator molecule, TNFAIP3, exhibited prominent variability between individual samples, and methylation of cytosine nucleotides in the TNFAIP3 promoter was found to be correlated with this variability among glaucomatous donors. CONCLUSIONS Findings of this study reveal a number of proteins upregulated in the glaucomatous human retina that exhibit many links to TNF-α/TNFR1 signaling. By highlighting various signaling molecules and regulators involved in cell death and immune response pathways and by correlating proteomic findings with epigenetic alterations, these findings provide a framework motivating further research.
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Affiliation(s)
- Xiangjun Yang
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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Cummins TD, Mendenhall MD, Lowry MN, Korte EA, Barati MT, Khundmiri SJ, Salyer SA, Klein JB, Powell DW. Elongin C is a mediator of Notch4 activity in human renal tubule cells. Biochim Biophys Acta 2011; 1814:1748-57. [PMID: 22001063 DOI: 10.1016/j.bbapap.2011.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 09/12/2011] [Accepted: 09/23/2011] [Indexed: 10/17/2022]
Abstract
Notch proteins (Notch 1-4) are a family of trans-membrane cell surface receptors that are converted into transcriptional regulators when activated by interactions with cell surface ligands on adjacent cells. Ligand-binding stimulates proteolytic cleavage of the trans-membrane domain, releasing an active intracellular domain (ICD) that translocates to the nucleus and impacts transcription. In transit, the ICD may interact with regulatory proteins that modulate the expression and transcriptional activity. We have found that Notch4(ICD) expression is enhanced in the tubule cells of fibrotic kidneys from diabetic mice and humans and identified Notch4(ICD) interacting proteins that could be pertinent to normal and pathological functions. Using proteomic techniques, several components of the Elongin C complex were identified as candidate Notch4(ICD) interactors. Elongin C complexes can function as ubiquitin ligases capable of regulating proteasomal degradation of specific protein substrates. Our studies indicate that ectopic Elongin C expression stimulates Notch4(ICD) degradation and inhibits its transcriptional activity in human kidney tubule HK11 cells. Blocking Elongin C mediated degradation by MG132 indicates the potential for ubiquitin-mediated Elongin C regulation of Notch4(ICD). Functional interaction of Notch4(ICD) and Elongin C provides novel insight into regulation of Notch signaling in epithelial cell biology and disease.
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Affiliation(s)
- Timothy D Cummins
- Departments of Biochemistry and Molecular Biology, University of Kentucky, KY, USA
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Stewart EV, Nwosu CC, Tong Z, Roguev A, Cummins TD, Kim DU, Hayles J, Park HO, Hoe KL, Powell DW, Krogan NJ, Espenshade PJ. Yeast SREBP cleavage activation requires the Golgi Dsc E3 ligase complex. Mol Cell 2011; 42:160-71. [PMID: 21504829 DOI: 10.1016/j.molcel.2011.02.035] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 12/29/2010] [Accepted: 02/22/2011] [Indexed: 12/25/2022]
Abstract
Mammalian lipid homeostasis requires proteolytic activation of membrane-bound sterol regulatory element binding protein (SREBP) transcription factors through sequential action of the Golgi Site-1 and Site-2 proteases. Here we report that while SREBP function is conserved in fungi, fission yeast employs a different mechanism for SREBP cleavage. Using genetics and biochemistry, we identified four genes defective for SREBP cleavage, dsc1-4, encoding components of a transmembrane Golgi E3 ligase complex with structural homology to the Hrd1 E3 ligase complex involved in endoplasmic reticulum-associated degradation. The Dsc complex binds SREBP and cleavage requires components of the ubiquitin-proteasome pathway: the E2-conjugating enzyme Ubc4, the Dsc1 RING E3 ligase, and the proteasome. dsc mutants display conserved aggravating genetic interactions with components of the multivesicular body pathway in fission yeast and budding yeast, which lacks SREBP. Together, these data suggest that the Golgi Dsc E3 ligase complex functions in a post-ER pathway for protein degradation.
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Affiliation(s)
- Emerson V Stewart
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Nanda SK, Venigalla RKC, Ordureau A, Patterson-Kane JC, Powell DW, Toth R, Arthur JSC, Cohen P. Polyubiquitin binding to ABIN1 is required to prevent autoimmunity. ACTA ACUST UNITED AC 2011; 208:1215-28. [PMID: 21606507 PMCID: PMC3173241 DOI: 10.1084/jem.20102177] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The polyubiquitin-binding domain of ABIN1 limits TLR-induced MyD88 signaling to prevent spontaneous autoimmunity in mice. The protein ABIN1 possesses a polyubiquitin-binding domain homologous to that present in nuclear factor κB (NF-κB) essential modulator (NEMO), a component of the inhibitor of NF-κB (IκB) kinase (IKK) complex. To address the physiological significance of polyubiquitin binding, we generated knockin mice expressing the ABIN1[D485N] mutant instead of the wild-type (WT) protein. These mice developed all the hallmarks of autoimmunity, including spontaneous formation of germinal centers, isotype switching, and production of autoreactive antibodies. Autoimmunity was suppressed by crossing to MyD88−/− mice, demonstrating that toll-like receptor (TLR)–MyD88 signaling pathways are needed for the phenotype to develop. The B cells and myeloid cells of the ABIN1[D485N] mice showed enhanced activation of the protein kinases TAK, IKK-α/β, c-Jun N-terminal kinases, and p38α mitogen-activated protein kinase and produced more IL-6 and IL-12 than WT. The mutant B cells also proliferated more rapidly in response to TLR ligands. Our results indicate that the interaction of ABIN1 with polyubiquitin is required to limit the activation of TLR–MyD88 pathways and prevent autoimmunity.
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Affiliation(s)
- Sambit K Nanda
- Medical Research Council Protein Phosphorylation Unit, Sir James Black Centre, University of Dundee, Dundee DD1 5EH, Scotland, UK.
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Farley AR, Powell DW, Weaver CM, Jennings JL, Link AJ. Assessing the components of the eIF3 complex and their phosphorylation status. J Proteome Res 2011; 10:1481-94. [PMID: 21280672 DOI: 10.1021/pr100877m] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The eukaryotic initiation factor 3 (eIF3) is an essential, highly conserved multiprotein complex that is a key component in the recruitment and assembly of the translation initiation machinery. To better understand the molecular function of eIF3, we examined its composition and phosphorylation status in Saccharomyces cerevisiae. The yeast eIF3 complex contains five core components: Rpg1, Nip1, Prt1, Tif34, and Tif35. 2-D LC-MS/MS analysis of affinity purified eIF3 complexes showed that several other initiation factors (Fun12, Tif5, Sui3, Pab1, Hcr1, and Sui1) and the casein kinase 2 complex (CK2) copurify. In Vivo metabolic labeling of proteins with (32)P revealed that Nip1 is phosphorylated. Using 2-D LC-MS/MS analysis of eIF3 complexes, we identified Prt1 phosphopeptides indicating phosphorylation at S22 and T707 and a Tif5 phosphopeptide with phosphorylation at T191. Additionally, we used immobilized metal affinity chromatography (IMAC) to enrich for eIF3 phosphopeptides and tandem mass spectrometry to identify phosphorylated residues. We found that three CK2 consensus sequences in Nip1 are phosphorylated: S98, S99, and S103. Using in vitro kinase assays, we showed that CK2 phophorylates Nip1 and that a synthetic Nip1 peptide containing S98, S99, and S103 competitively inhibits the reaction. Replacement of these three Nip1 serines with alanines causes a slow growth phenotype.
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Affiliation(s)
- Adam R Farley
- Department of Biochemisty, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2363, United States
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Abstract
The non-white blood cell mesenchymal elements of the intestinal lamina propria are the myofibroblasts, fibroblasts, pericytes, stromal stem cells, muscularis mucosae, and the smooth muscle of the villus core associated with the lymphatic lacteal. We review the functional anatomy of these mesenchymal cells, what is known about their origin in the embryo and their replacement in adults, their putative role in intestinal mucosal morphogenesis, and the intestinal stem cell niche, and we consider new information about myofibroblasts as nonprofessional immune cells. Although our knowledge of the function of mesenchymal cells in intestinal disease is rudimentary, we briefly consider here their roles in cancer and intestinal inflammation.
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Affiliation(s)
- I V Pinchuk
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555-0764, USA.
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Luerman GC, Powell DW, Uriarte SM, Cummins TD, Merchant ML, Ward RA, McLeish KR. Identification of phosphoproteins associated with human neutrophil granules following chemotactic peptide stimulation. Mol Cell Proteomics 2010; 10:M110.001552. [PMID: 21097543 DOI: 10.1074/mcp.m110.001552] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Regulated exocytosis of neutrophil intracellular storage granules is necessary for neutrophil participation in the inflammatory response. The signal transduction pathways that participate in neutrophil exocytosis are complex and poorly defined. Several protein kinases, including p38 MAPK and the nonreceptor tyrosine kinases, Hck and Fgr, participate in this response. However, the downstream targets of these kinases that regulate exocytosis are unknown. The present study combined a novel inhibitor of neutrophil exocytosis with proteomic techniques to identify phosphopeptides and phosphoproteins from a population of gelatinase and specific granules isolated from unstimulated and fMLF-stimulated neutrophils. To prevent loss of granule-associated phosphoproteins upon exocytosis, neutrophils were pretreated with a TAT-fusion protein containing a SNARE domain from SNAP-23 (TAT-SNAP-23), which inhibited fMLF-stimulated CD66b-containing granule exocytosis by 100±10%. Following TAT-SNAP-23 pretreatment, neutrophils were stimulated with the chemotactic peptide fMLF for 0 min, 1 min, and 2 min. Granules were isolated by gradient centrifugation and subjected to proteolytic digestion with trypsin or chymotrypsin to obtain peptides from the outer surface of the granule. Phosphopeptides were enriched by gallium or TiO2 affinity chromatography, and phosphopeptides and phosphorylation sites were identified by reversed phase high performance liquid chromatography-electrospray ionization-tandem MS. This resulted in the identification of 243 unique phosphopeptides corresponding to 235 proteins, including known regulators of vesicle trafficking. The analysis identified 79 phosphoproteins from resting neutrophils, 81 following 1 min of fMLF stimulation, and 118 following 2 min of stimulation. Bioinformatic analysis identified a potential Src tyrosine kinase motif from a phosphopeptide corresponding to G protein coupled receptor kinase 5 (GRK5). Phosphorylation of GRK5 by Src was confirmed by an in vitro kinase reaction and by precursor ion scanning for phospho-tyrosine specific immonium ions containing Tyr251 and Tyr253. Immunoprecipitation of phosphorylated GRK5 from intact cells was reduced by a Src inhibitor. In conclusion, targets of signal transduction pathways were identified that are candidates to regulate neutrophil granule exocytosis.
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Affiliation(s)
- Gregory C Luerman
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY 40202, USA
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Luo C, Yang X, Kain AD, Powell DW, Kuehn MH, Tezel G. Glaucomatous tissue stress and the regulation of immune response through glial Toll-like receptor signaling. Invest Ophthalmol Vis Sci 2010; 51:5697-707. [PMID: 20538986 DOI: 10.1167/iovs.10-5407] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the regulation of immune system activity associated with Toll-like receptor (TLR) signaling in glaucoma. METHODS Retinal protein samples obtained from human donor eyes with (n = 10) or without (n = 10) glaucoma were analyzed by a quantitative proteomic approach involving mass spectrometry. Cellular localization of TLR2, -3, and -4 was also determined by immunohistochemical analysis of an additional group of human donor eyes with glaucoma (n = 34) and control eyes (n = 20). In addition, in vitro experiments were performed in rat retinal microglia and astrocytes to determine glial TLR expression and immunoregulatory function after exposure to exogenous heat shock proteins (HSPs) and H(2)O(2)-induced oxidative stress. RESULTS Proteomic analyses of the human retina detected expression and differential regulation of different TLRs in glaucomatous samples. Parallel to the upregulation of TLR signaling, proteomic findings were also consistent with a prominent increase in the expression of HSPs in glaucoma. Immunohistochemical analysis supported upregulated expression of TLRs on both microglia and astrocytes in the glaucomatous retina. In vitro experiments provided additional evidence that HSPs and oxidative stress upregulate glial TLR and MHC class II expression and cytokine production through TLR signaling and stimulate proliferation and cytokine secretion of co-cultured T cells during antigen presentation. CONCLUSIONS The findings of this study support the upregulation of TLR signaling in human glaucoma, which may be associated with innate and adaptive immune responses. In vitro findings showed that components of glaucomatous tissue stress, including upregulated HSPs and oxidative stress, may initiate the immunostimulatory signaling through glial TLRs.
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Affiliation(s)
- Cheng Luo
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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Tezel G, Yang X, Luo C, Kain AD, Powell DW, Kuehn MH, Kaplan HJ. Oxidative stress and the regulation of complement activation in human glaucoma. Invest Ophthalmol Vis Sci 2010; 51:5071-82. [PMID: 20484586 DOI: 10.1167/iovs.10-5289] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE As part of ongoing studies on proteomic alterations during glaucomatous neurodegeneration, this study focused on the complement system. METHODS Human retinal protein samples obtained from donor eyes with (n = 10) or without (n = 10) glaucoma were analyzed by a quantitative proteomic approach using mass spectrometry. Cellular localization of protein expression for different complement components and regulators were also determined by immunohistochemical analysis of an additional group of human donor eyes with glaucoma (n = 34) compared with age-matched control eyes without glaucoma (n = 20). In addition, to determine the regulation of complement factor H (CFH) by oxidative stress, in vitro experiments were performed using rat retinal cell cultures incubated in the presence and absence of an oxidant treatment. RESULTS Proteomic analysis detected the expression and differential regulation of several complement components in glaucomatous samples, which included proteins involved in the classical and the lectin pathways of complement activation. In addition, several complement regulatory proteins were detected in the human retinal proteome, and glaucomatous samples exhibited a trend toward downregulation of CFH expression. In vitro experiments revealed that oxidative stress, which was also prominently detectable in the glaucomatous human retinas, downregulated CFH expression in retinal cells. CONCLUSIONS These findings expand the current knowledge of complement activation by presenting new evidence in human glaucoma and support that despite important roles in tissue cleaning and healing, a potential deficiency in intrinsic regulation of complement activation, as is evident in the presence of oxidative stress, may lead to uncontrolled complement attack with neurodestructive consequences.
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Affiliation(s)
- Gülgün Tezel
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, USA.
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Dean WL, Lee MJ, Cummins TD, Schultz DJ, Powell DW. Proteomic and functional characterisation of platelet microparticle size classes. Thromb Haemost 2010; 102:711-8. [PMID: 19806257 DOI: 10.1160/th09-04-243] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
UNLABELLED Activated platelets release large lipid-protein complexes termed microparticles. These platelet microparticles (PMP) are composed of vesicular fragments of the plasma membrane and alpha-granules. PMP facilitate coagulation, promote platelet and leukocyte adhesion to the subendothelial matrix, support angiogenesis and stimulate vascular smooth muscle proliferation. OBJECTIVES PMP were separated into 4 size classes to facilitate identification of active protein and lipid components. PMP were obtained from activated human platelets and separated into 4 size classes by gel filtration chromatography. Proteins were identified using 2-dimensional, liquid chromatography tandem mass spectrometry. Functional effects on platelets were determined using the PFA-100 and on endothelial cells by measuring transendothelial cell electrical resistance. PMP size classes differed significantly in their contents of plasma membrane receptors and adhesion molecules, chemokines, growth factors and protease inhibitors. The two smallest size classes (3 and 4) inhibited collagen/adenosine-diphosphate-mediated platelet thrombus formation, while fractions 2 and 4 stimulated barrier formation by endothelial cells. Heat denaturation blocked the effect of fraction 4 on endothelial cell function, but not fraction 2 implying that the active component in fraction 4 is a protein and in fraction 2 is a heat-stable protein or lipid but not sphingosine-1-phosphate. Proteomic and functional analysis of PMP size fractions has shown that PMP can be separated into different size classes that differ in protein components, protein/lipid ratio, and functional effects on platelets and endothelial cells. This analysis will facilitate identification of active components in the PMP and clarify their involvement in diseases such as atherosclerosis and cancer.
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Affiliation(s)
- William L Dean
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine Louisville, KY 40292, USA.
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Merchant ML, Powell DW, Wilkey DW, Cummins TD, Deegens JK, Rood IM, McAfee KJ, Fleischer C, Klein E, Klein JB. Microfiltration isolation of human urinary exosomes for characterization by MS. Proteomics Clin Appl 2009; 4:84-96. [PMID: 21137018 DOI: 10.1002/prca.200800093] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2008] [Revised: 09/14/2009] [Accepted: 09/28/2009] [Indexed: 12/12/2022]
Abstract
PURPOSE The purpose of this study was to address the hypothesis that small vesicular urinary particles known as exosomes could be selectively microfiltered using low protein-binding size exclusion filters, thereby simplifying their use in clinical biomarker discovery studies. EXPERIMENTAL DESIGN We characterized a microfiltration approach using a low protein binding, hydrophilized polyvinylidene difluoride membrane to easily and efficiently isolate urinary exosomes from fresh, room temperature or 4°C urine, with a simultaneous depletion of abundant urinary proteins. Using LC-MS, immunoblot analysis, and electron microscopy methods, we demonstrate this method to isolate intact exosomes and thereby enrich for a low abundant urinary proteome. RESULTS In comparison to other standard methods of exosome isolation including ultracentrifugation and nanofiltration, we demonstrate equivalent enrichment of the exosome proteome with reduced co-purification of abundant urinary proteins. CONCLUSION AND CLINICAL RELEVANCE In conclusion, we demonstrate a microfiltration isolation method that preserves the exosome structure, reduces contamination from higher abundant urinary proteins, and can be easily implemented into mass spectrometry analysis for biomarker discovery efforts or incorporation into routine clinical laboratory applications to yield higher sample throughput.
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Cummins TD, Barati MT, Coventry SC, Salyer SA, Klein JB, Powell DW. Quantitative mass spectrometry of diabetic kidney tubules identifies GRAP as a novel regulator of TGF-beta signaling. Biochim Biophys Acta 2009; 1804:653-61. [PMID: 19836472 DOI: 10.1016/j.bbapap.2009.09.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 09/22/2009] [Accepted: 09/29/2009] [Indexed: 01/13/2023]
Abstract
The aim of this study was to define novel mediators of tubule injury in diabetic kidney disease. For this, we used state-of-the-art proteomic methods combined with a label-free quantitative strategy to define protein expression differences in kidney tubules from transgenic OVE26 type 1 diabetic and control mice. The analysis was performed with diabetic samples that displayed a pro-fibrotic phenotype. We have identified 476 differentially expressed proteins. Bioinformatic analysis indicated several clusters of regulated proteins in relevant functional groups such as TGF-beta signaling, tight junction maintenance, oxidative stress, and glucose metabolism. Mass spectrometry detected expression changes of four physiologically relevant proteins were confirmed by immunoblot analysis. Of these, the Grb2-related adaptor protein (GRAP) was up-regulated in kidney tubules from diabetic mice and fibrotic kidneys from diabetic patients, and subsequently confirmed as a novel component of TGF-beta signaling in cultured human renal tubule cells. Thus, indicating a potential novel role for GRAP in TGF-beta-induced tubule injury in diabetic kidney disease. Although we targeted a specific disease, this approach offers a robust, high-sensitivity methodology that can be applied to the discovery of novel mediators for any experimental or disease condition.
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Affiliation(s)
- Timothy D Cummins
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY, USA
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Tezel G, Yang X, Luo C, Cai J, Kain AD, Powell DW, Kuehn MH, Pierce WM. Hemoglobin expression and regulation in glaucoma: insights into retinal ganglion cell oxygenation. Invest Ophthalmol Vis Sci 2009; 51:907-19. [PMID: 19741249 DOI: 10.1167/iovs.09-4014] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
PURPOSE To determine expression, cellular distribution, and regulation of hemoglobin (Hb) in normal and glaucomatous tissues. METHODS Proteomic analysis of Hb expression was conducted on protein samples from ocular hypertensive and control rat eyes and human donor eyes with or without glaucoma. Proteomic findings were validated by quantitative (q)RT-PCR, Western blot analysis, immunohistochemistry, and the analysis of new Hb synthesis in culture. Hypoxic regulation of Hb expression was also studied in primary cultures of rat RGCs and macroglia and after transfer of the glia-conditioned medium to RGCs. The role of erythropoietin (EPO) signaling in Hb induction and cell survival was determined by applying recombinant (r)EPO treatment and performing EPO neutralization experiments by using soluble EPO receptor treatment of hypoxic cultures. RESULTS In vivo findings revealed Hb expression in the retina and optic nerve head macroglia and RGCs, suggesting an approximately two-fold upregulation in ocular hypertensive rat eyes and glaucomatous human donor eyes relative to the control eyes. In vitro findings collectively supported that hypoxia boosts glial Hb expression through hypoxia-inducible EPO signaling in an autocrine manner. Based on passive transfer experiments, hypoxia-induced production of glial EPO was also found to upregulate Hb expression in RGCs in a paracrine manner, thereby increasing the hypoxic survival of these neurons. CONCLUSIONS Findings of this study provide new insights into tissue oxygen transport in the inner retina and optic nerve head through the regulated expression of Hb in macroglia and RGCs. Upregulation of Hb expression appears to be an intrinsic protective mechanism to facilitate cellular oxygenation and may also provide free radical scavenging.
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Affiliation(s)
- Gülgün Tezel
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.
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Dean WL, Lee MJ, Cummins TD, Schultz DJ, Powell DW. Proteomic and functional characterisation of platelet microparticle size classes. Thromb Haemost 2009. [DOI: 10.1160/th09-04-0243] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Beck LH, Bonegio RGB, Lambeau G, Beck DM, Powell DW, Cummins TD, Klein JB, Salant DJ. M-type phospholipase A2 receptor as target antigen in idiopathic membranous nephropathy. N Engl J Med 2009; 361:11-21. [PMID: 19571279 PMCID: PMC2762083 DOI: 10.1056/nejmoa0810457] [Citation(s) in RCA: 1474] [Impact Index Per Article: 98.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Idiopathic membranous nephropathy, a common form of the nephrotic syndrome, is an antibody-mediated autoimmune glomerular disease. Serologic diagnosis has been elusive because the target antigen is unknown. METHODS We performed Western blotting of protein extracts from normal human glomeruli with serum samples from patients with idiopathic or secondary membranous nephropathy or other proteinuric or autoimmune diseases and from normal controls. We used mass spectrometry to analyze the reactive protein bands and confirmed the identity and location of the target antigen with a monospecific antibody. RESULTS Serum samples from 26 of 37 patients (70%) with idiopathic but not secondary membranous nephropathy specifically identified a 185-kD glycoprotein in nonreduced glomerular extract. Mass spectrometry of the reactive protein band detected the M-type phospholipase A(2) receptor (PLA(2)R). Reactive serum specimens recognized recombinant PLA(2)R and bound the same 185-kD glomerular protein as did the monospecific anti-PLA(2)R antibody. Anti-PLA(2)R autoantibodies in serum samples from patients with membranous nephropathy were mainly IgG4, the predominant immunoglobulin subclass in glomerular deposits. PLA(2)R was expressed in podocytes in normal human glomeruli and colocalized with IgG4 in immune deposits in glomeruli of patients with membranous nephropathy. IgG eluted from such deposits in patients with idiopathic membranous nephropathy, but not in those with lupus membranous or IgA nephropathy, recognized PLA(2)R. CONCLUSIONS A majority of patients with idiopathic membranous nephropathy have antibodies against a conformation-dependent epitope in PLA(2)R. PLA(2)R is present in normal podocytes and in immune deposits in patients with idiopathic membranous nephropathy, indicating that PLA(2)R is a major antigen in this disease.
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Powell DW, Bertram CC, Cummins TD, Barati MT, Zheng S, Epstein PN, Klein JB. Renal tubulointerstitial fibrosis in OVE26 type 1 diabetic mice. Nephron Exp Nephrol 2009; 111:e11-9. [PMID: 19052473 DOI: 10.1159/000178763] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 09/30/2008] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Tubulointerstitial fibrosis (TIF) is a prominent feature of progressive diabetic nephropathy. The goal of this study was to determine if hallmarks of TIF occur in the transgenic OVE26 type 1 diabetic mouse and define signaling events associated with TIF. METHODS The expression patterns of several phenotypic markers of TIF were determined in kidneys of OVE26 diabetic and control mice by immunohistochemistry and immunoblot analysis. RESULTS Pathological signatures of TIF are an accumulation of myofibroblasts and excessive deposition of extracellular matrix in the tubulointerstitium. Kidneys from OVE26 diabetic animals exhibited an increase in tubulointerstitial myofibroblast marker (alpha-smooth muscle actin), fibronectin and collagen I staining. Abundance of the pro-fibrotic cytokine TGF-beta was also enhanced in diabetic tubules. As injury involving loss of epithelial cell-cell contact promotes tissue fibrosis, we examined expression of the adhesion protein, E-cadherin. The percent of E-cadherin-stained tubules was decreased in diabetic kidneys. Prominent regulators of TGF-beta signaling, glycogen synthase kinase-3 (GSK-3) alpha and beta, were also differentially expressed. CONCLUSIONS These results indicate that TGF-beta-induced TIF occurs in OVE26 diabetic mice, providing a practical in vivo model for defining novel regulatory events and treatment strategies for diabetes-induced TIF.
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Affiliation(s)
- David W Powell
- Department of Medicine, University of Louisville School of Medicine, Louisville, Ky., USA.
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Burg JS, Powell DW, Chai R, Hughes AL, Link AJ, Espenshade PJ. Insig regulates HMG-CoA reductase by controlling enzyme phosphorylation in fission yeast. Cell Metab 2008; 8:522-31. [PMID: 19041767 PMCID: PMC2646361 DOI: 10.1016/j.cmet.2008.09.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 07/21/2008] [Accepted: 09/10/2008] [Indexed: 01/27/2023]
Abstract
Insig functions as a central regulator of cellular cholesterol homeostasis by controlling activity of HMG-CoA reductase (HMGR) in cholesterol synthesis. Insig both accelerates the degradation of HMGR and suppresses HMGR transcription through the SREBP-Scap pathway. The fission yeast Schizosaccharomyces pombe encodes homologs of Insig, HMGR, SREBP, and Scap, called ins1(+), hmg1(+), sre1(+), and scp1(+). Here, we characterize fission yeast Insig and demonstrate that Ins1 is dedicated to regulation of Hmg1, but not the Sre1-Scp1 pathway. Using a sterol-sensing domain mutant of Hmg1, we demonstrate that Ins1 binding to Hmg1 inhibits enzyme activity by promoting phosphorylation of the Hmg1 active site, which increases the K(M) for NADPH. Ins1-dependent phosphorylation of Hmg1 requires the MAP kinase Sty1/Spc1, and Hmg1 phosphorylation is physiologically regulated by nutrient stress. Thus, in fission yeast, Insig regulates sterol synthesis by a different mechanism than in mammalian cells, controlling HMGR phosphorylation in response to nutrient supply.
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Affiliation(s)
- John S Burg
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Merchant ML, Cummins TD, Wilkey DW, Salyer SA, Powell DW, Klein JB, Lederer ED. Proteomic analysis of renal calculi indicates an important role for inflammatory processes in calcium stone formation. Am J Physiol Renal Physiol 2008; 295:F1254-8. [PMID: 18701630 DOI: 10.1152/ajprenal.00134.2008] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Even though renal stones/calculi occur in approximately 10% of individuals, they are an enormous economic burden to the entire US health system. While the relative metabolic composition of renal calculi is generally known, there is no clear understanding of the genetics of renal stone formation, nor are there clear prognostic indicators of renal stone formation. The application of proteomics to the analysis of renal calculi axiomatically holds that insight into renal stone pathobiology can be gained by a more comprehensive understanding of renal calculus protein composition. We analyzed isolated renal stone matrix proteins with mass spectrometric and immunohistochemical methods identifying 158 proteins with high confidence, including 28 common proteins. The abundant proteins included those identified previously in stones and proteins identified here for the first time, such as myeloid lineage-specific, integral membrane and lipid regulatory proteins. Pathway analyses of all proteins identified suggested that a significant fraction of the most abundant matrix proteins participate in inflammatory processes. These proteomic results support the hypothesis that stone formation induces a cellular inflammatory response and the protein components of this response contribute to the abundant stone matrix proteome.
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Affiliation(s)
- Michael L Merchant
- Department of Medicine, James Graham Brown Cancer Center, University of Louiville, Rm. 102S, Donald Baxter Research Bldg., 570 S. Preston St., Louisville, KY 40202, USA.
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Abstract
The direction of net fluid transport in the gut is determined by the algebraic sum of Na+ absorption and Cl- secretion. Na+ absorption by small intestinal villous cells and colonic surface cells is controlled primarily by electrically neutral (NaCl) and electrogenic (Na+-glucose, Na+-amino acid, amiloride-insensitive, and amiloride-sensitive Na+ conductance) entry processes in the apical membrane. Neutral NaCl entry appears to be the result of parallel Na+:H- and Cl-:HCO3- exchangers operating at equal stoichiometry. Uncoupled exchangers operating at different stoichiometry may result in net HCO3- absorption (jejunum), net HCO3- secretion (ileum and proximal colon) or HCO3-:Cl- exchange (distal colon). Increases in intracellular cyclic nucleotides and/or ionized Ca2+ inhibit NaCl entry and, in vivo, promote HCO3- and Cl- secretion. Cl- secretion by crypt cells is the result of cyclic nucleotide-mediated or Ca2+-mediated Cl- conductance channels in the apical membrane which allow Cl- to exit down an electrochemical gradient created by a basolateral NaKCl2 entry process. Cyclic nucleotides may act via specific A and G protein kinases. They also release Ca2+ from intracellular stores and thus could alter transport via Ca2+ (and calmodulin)-activated kinases. Ca2+-dependent secretory agents initiate phospholipid hydrolysis and stimulate secretion via the resulting hydrolytic products: arachidonic acid metabolites when bradykinin is the stimulus or diacylglycerol and/or inositol trisphosphate when acetylcholine is the stimulus. The arachidonic acid metabolites may then stimulate cyclic nucleotide production, while diacylglycerol activates a specific Ca2+/phospholipid-dependent protein kinase (C kinase), and inositol trisphosphate releases Ca2+ from the endoplasmic reticulum. The interrelationships between these intracellular messengers and their exact modes of action remain to be clarified.
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Uriarte SM, Powell DW, Luerman GC, Merchant ML, Cummins TD, Jog NR, Ward RA, McLeish KR. Comparison of Proteins Expressed on Secretory Vesicle Membranes and Plasma Membranes of Human Neutrophils. J Immunol 2008; 180:5575-81. [DOI: 10.4049/jimmunol.180.8.5575] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Di Mari JF, Saada JI, Mifflin RC, Valentich JD, Powell DW. HETEs enhance IL-1-mediated COX-2 expression via augmentation of message stability in human colonic myofibroblasts. Am J Physiol Gastrointest Liver Physiol 2007; 293:G719-28. [PMID: 17640979 DOI: 10.1152/ajpgi.00117.2007] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Proinflammatory cytokines and eicosanoids are central players in intestinal inflammation. IL-1, a key cytokine associated with intestinal mucosal inflammation, induces COX-2 expression in human colonic myofibroblasts (CMF) and increased prostaglandin E(2) secretion is associated with inflammatory bowel disease (IBD) and colorectal cancer (CRC). We have previously demonstrated that IL-1alpha-induced cyclooxygenase-2 (COX-2) expression is the result of NF-kappaB- and ERK-mediated transcription, as well as COX-2 message stabilization, which depends on p38, MAPKAPK-2 (MK-2) and human antigen R (HuR) RNA binding protein activation. Lipoxygenase (LOX)-derived hydroxyeicosatetraenoic acids (HETEs) are elevated in IBD and colonic adenomas and "cross talk" has been observed between the COX and LOX pathways. Since COX-2 expression is primarily in CMFs in colonic adenomas, we examined the impact of LOX metabolites, particularly HETEs, on IL-1alpha-induced COX-2 expression in human CMFs. Although 5(S)-, 12(R)-, and 15(S)-HETEs alone had little to no effect on COX-2 expression, they enhanced IL-1-mediated COX-2 expression 3.6 +/- 0.5-fold. Studies utilizing heterogeneous nuclear RNA amplification and 5,6-dichloro-beta-d-ribofuranosylbenzimidazole treatment were undertaken to measure COX-2 transcription and message stabilization, respectively. We found that HETEs enhanced IL-1-induced COX-2 mRNA levels in CMF as the result of increased p38, MK-2, and HuR activity, increasing message stability greater than that observed with IL-1 alone. Thus HETEs can act synergistically with IL-1alpha to induce COX-2 expression in human CMFs. HETEs may play a role in both colonic inflammation and in increasing the risk of CRC in IBD independently and via induction of COX-2-mediated prostaglandin secretion.
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Affiliation(s)
- J F Di Mari
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA.
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Burg JS, Bard M, Powell DW, Espenshade PJ. Insig Regulates HMG‐CoA Reductase by a Non‐Degradative Mechanism in Fission Yeast. FASEB J 2007. [DOI: 10.1096/fasebj.21.5.a609-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- John S. Burg
- Department of Cell BiologyJohns Hopkins University School of Medicine725 N. Wolfe St., Physiology 107BaltimoreMD21205
| | - Martin Bard
- Indiana University School of Science723 W. Michigan Street, Room 324AIndianapolisIN46202
| | - David W. Powell
- Department of Medicine/NephrologyUniversity of Louisville615 South Preston StreetLouisvilleKY40202
| | - Peter J. Espenshade
- Department of Cell BiologyJohns Hopkins University School of Medicine725 N. Wolfe St., Physiology 107BaltimoreMD21205
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