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Kulasekararaj AG, Lehtinen AE, Forsyth C, Gandhi S, Griffin M, Körper S, Mikala G, Muus P, Overgaard U, Patriquin CJ, Pullon H, Shen YM, Spearing R, Szer J, De la Borderie G, Duda PW, Farzaneh-Far R, Ragunathan S, Sayegh CE, Vadysirisack DD, Schrezenmeier H. Phase II trials of zilucoplan in paroxysmal nocturnal hemoglobinuria. Haematologica 2024; 109:929-935. [PMID: 37534517 PMCID: PMC10905099 DOI: 10.3324/haematol.2022.281780] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 07/27/2023] [Indexed: 08/04/2023] Open
Affiliation(s)
- Austin G Kulasekararaj
- King's College Hospital-NHS Foundation Trust, NIHR/Wellcome King's Clinical Research Facility, London, UK and King's College London, London
| | - Anna-Elina Lehtinen
- Helsinki University Hospital Comprehensive Cancer Center and University of Helsinki, Helsinki
| | | | - Shreyans Gandhi
- King's College Hospital-NHS Foundation Trust, NIHR/Wellcome King's Clinical Research Facility, London, UK and King's College London, London
| | | | - Sixten Körper
- University of Ulm, Institute of Transfusion Medicine, and Institute of Transfusion Medicine and Immunogenetics Ulm, Red Cross Blood Transfusion Service Baden-Württemberg-Hessen and University Hospital Ulm, Ulm
| | - Gabor Mikala
- Central Hospital of Southern Pest National Institute of Hematology and Infectious Diseases, Budapest
| | - Petra Muus
- King's College Hospital-NHS Foundation Trust, NIHR/Wellcome King's Clinical Research Facility, London, UK and King's College London, London, UK; St. James's University Hospital, Leeds
| | | | | | | | | | | | - Jeff Szer
- Peter MacCallum Cancer Centre and The Royal Melbourne Hospital, Melbourne, VIC
| | | | | | | | | | | | | | - Hubert Schrezenmeier
- University of Ulm, Institute of Transfusion Medicine, and Institute of Transfusion Medicine and Immunogenetics Ulm, Red Cross Blood Transfusion Service Baden-Württemberg-Hessen and University Hospital Ulm, Ulm.
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Tang GQ, Tang Y, Dhamnaskar K, Hoarty MD, Vyasamneni R, Vadysirisack DD, Ma Z, Zhu N, Wang JG, Bu C, Cong B, Palmer E, Duda PW, Sayegh C, Ricardo A. Corrigendum: Zilucoplan, a macrocyclic peptide inhibitor of human complement component 5, uses a dual mode of action to prevent terminal complement pathway activation. Front Immunol 2023; 14:1282155. [PMID: 37818356 PMCID: PMC10561601 DOI: 10.3389/fimmu.2023.1282155] [Citation(s) in RCA: 1] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 09/08/2023] [Indexed: 10/12/2023] Open
Abstract
[This corrects the article DOI: 10.3389/fimmu.2023.1213920.].
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Affiliation(s)
| | - Yalan Tang
- UCB Pharma, Cambridge, MA, United States
| | | | | | | | | | - Zhong Ma
- UCB Pharma/Ra Pharmaceuticals, Cambridge, MA, United States
| | - Nanqun Zhu
- UCB Pharma/Ra Pharmaceuticals, Cambridge, MA, United States
| | | | - Charlie Bu
- UCB Pharma, Cambridge, MA, United States
| | | | | | | | - Camil Sayegh
- UCB Pharma/Ra Pharmaceuticals, Cambridge, MA, United States
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Tang GQ, Tang Y, Dhamnaskar K, Hoarty MD, Vyasamneni R, Vadysirisack DD, Ma Z, Zhu N, Wang JG, Bu C, Cong B, Palmer E, Duda PW, Sayegh C, Ricardo A. Zilucoplan, a macrocyclic peptide inhibitor of human complement component 5, uses a dual mode of action to prevent terminal complement pathway activation. Front Immunol 2023; 14:1213920. [PMID: 37622108 PMCID: PMC10446491 DOI: 10.3389/fimmu.2023.1213920] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 07/17/2023] [Indexed: 08/26/2023] Open
Abstract
Introduction The complement system is a key component of the innate immune system, and its aberrant activation underlies the pathophysiology of various diseases. Zilucoplan is a macrocyclic peptide that binds and inhibits the cleavage/activation of human complement component 5 (C5). We present in vitro and ex vivo data on the mechanism of action of zilucoplan for the inhibition of C5 activation, including two clinically relevant C5 polymorphisms at R885. Methods The interaction of zilucoplan with C5, including for clinical C5 R885 variants, was investigated using surface plasmon resonance (SPR), hemolysis assays, and ELISA. The interference of C5b6 formation by zilucoplan was investigated by native gel analysis and hemolysis assay. The permeability of zilucoplan in a reconstituted basement membrane was assessed by the partition of zilucoplan on Matrigel-coated transwell chambers. Results Zilucoplan specifically bound human complement C5 with high affinity, competitively inhibited the binding of C5 to C3b, and blocked C5 cleavage by C5 convertases and the assembly of the cytolytic membrane attack complex (MAC, or C5b9). Zilucoplan fully prevented the in vitro activation of C5 clinical variants at R885 that have been previously reported to respond poorly to eculizumab treatment. Zilucoplan was further demonstrated to interfere with the formation of C5b6 and inhibit red blood cell (RBC) hemolysis induced by plasmin-mediated non-canonical C5 activation. Zilucoplan demonstrated greater permeability than a monoclonal C5 antibody in a reconstituted basement membrane model, providing a rationale for the rapid onset of action of zilucoplan observed in clinical studies. Conclusion Our findings demonstrate that zilucoplan uses a dual mode of action to potently inhibit the activation of C5 and terminal complement pathway including wild-type and clinical R885 variants that do not respond to eculizumab treatment. These data may be relevant to the clinically demonstrated benefits of zilucoplan.
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Affiliation(s)
| | - Yalan Tang
- UCB Pharma, Cambridge, MA, United States
| | | | | | | | | | - Zhong Ma
- UCB Pharma/Ra Pharmaceuticals, Cambridge, MA, United States
| | - Nanqun Zhu
- UCB Pharma/Ra Pharmaceuticals, Cambridge, MA, United States
| | | | - Charlie Bu
- UCB Pharma, Cambridge, MA, United States
| | | | | | | | - Camil Sayegh
- UCB Pharma/Ra Pharmaceuticals, Cambridge, MA, United States
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Obaid AH, Zografou C, Vadysirisack DD, Munro-Sheldon B, Fichtner ML, Roy B, Philbrick WM, Bennett JL, Nowak RJ, O'Connor KC. Heterogeneity of Acetylcholine Receptor Autoantibody-Mediated Complement Activity in Patients With Myasthenia Gravis. Neurol Neuroimmunol Neuroinflamm 2022; 9:9/4/e1169. [PMID: 35473886 PMCID: PMC9128035 DOI: 10.1212/nxi.0000000000001169] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 03/08/2022] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND OBJECTIVES Autoantibodies targeting the acetylcholine receptor (AChR), found in patients with myasthenia gravis (MG), mediate pathology through 3 mechanisms: complement-directed tissue damage, blocking of the acetylcholine binding site, and internalization of the AChR. Clinical assays, used to diagnose and monitor patients, measure only autoantibody binding. Consequently, they are limited in providing association with disease burden, understanding of mechanistic heterogeneity, and monitoring therapeutic response. The objective of this study was to develop a cell-based assay that measures AChR autoantibody-mediated complement membrane attack complex (MAC) formation. METHODS An HEK293T cell line-modified using CRISPR/Cas9 genome editing to disrupt expression of the complement regulator genes (CD46, CD55, and CD59)-was used to measure AChR autoantibody-mediated MAC formation through flow cytometry. RESULTS Serum samples (n = 155) from 96 clinically confirmed AChR MG patients, representing a wide range of disease burden and autoantibody titer, were tested along with 32 healthy donor (HD) samples. AChR autoantibodies were detected in 139 of the 155 (89.7%) MG samples through a cell-based assay. Of the 139 AChR-positive samples, autoantibody-mediated MAC formation was detected in 83 (59.7%), whereas MAC formation was undetectable in the HD group or AChR-positive samples with low autoantibody levels. MAC formation was positively associated with autoantibody binding in most patient samples; ratios (mean fluorescence intensity) of MAC formation to AChR autoantibody binding ranged between 0.27 and 48, with a median of 0.79 and an interquartile range of 0.43 (0.58-1.1). However, the distribution of ratios was asymmetric and included extreme values; 16 samples were beyond the 10-90 percentile, with high MAC to low AChR autoantibody binding ratio or the reverse. Correlation between MAC formation and clinical disease scores suggested a modest positive association (rho = 0.34, p = 0.0023), which included a subset of outliers that did not follow this pattern. MAC formation did not associate with exposure to immunotherapy, thymectomy, or MG subtypes defined by age-of-onset. DISCUSSION A novel assay for evaluating AChR autoantibody-mediated complement activity was developed. A subset of patients that lacks association between MAC formation and autoantibody binding or disease burden was identified. The assay may provide a better understanding of the heterogeneous autoantibody molecular pathology and identify patients expected to benefit from complement inhibitor therapy.
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Fichtner ML, Hoarty MD, Vadysirisack DD, Munro-Sheldon B, Nowak RJ, O’Connor KC. Myasthenia gravis complement activity is independent of autoantibody titer and disease severity. PLoS One 2022; 17:e0264489. [PMID: 35290370 PMCID: PMC8923450 DOI: 10.1371/journal.pone.0264489] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 02/12/2022] [Indexed: 11/18/2022] Open
Abstract
Acetylcholine receptor (AChR) autoantibodies, found in patients with autoimmune myasthenia gravis (MG), can directly contribute to disease pathology through activation of the classical complement pathway. Activation of the complement pathway in autoimmune diseases can lead to a secondary complement deficiency resulting in reduced complement activity, due to consumption, during episodes of disease activity. It is not clear whether complement activity in MG patients associates with measurements of disease activity or the titer of circulating pathogenic AChR autoantibodies. To explore such associations, as a means to identify a candidate biomarker, we measured complement activity in AChR MG samples (N = 51) using a CH50 hemolysis assay, then tested associations between these values and both clinical status and AChR autoantibody titer. The majority of the study subjects (88.2%) had complement activity within the range defined by healthy controls, while six patients (11.8%) showed reduced activity. No significant association between complement activity and disease status or AChR autoantibody titer was observed.
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Affiliation(s)
- Miriam L. Fichtner
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, United States of America
- Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut, United States of America
| | | | | | - Bailey Munro-Sheldon
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Richard J. Nowak
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Kevin C. O’Connor
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, United States of America
- Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut, United States of America
- * E-mail:
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Muldur S, Vadysirisack DD, Ragunathan S, Tang Y, Ricardo A, Sayegh CE, Irimia D. Human Neutrophils Respond to Complement Activation and Inhibition in Microfluidic Devices. Front Immunol 2021; 12:777932. [PMID: 34899737 PMCID: PMC8653703 DOI: 10.3389/fimmu.2021.777932] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [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: 09/16/2021] [Accepted: 10/29/2021] [Indexed: 12/30/2022] Open
Abstract
Complement activation is key to anti-microbial defenses by directly acting on microbes and indirectly by triggering cellular immune responses. Complement activation may also contribute to the pathogenesis of numerous inflammatory and immunological diseases. Consequently, intense research focuses on developing therapeutics that block pathology-causing complement activation while preserving anti-microbial complement activities. However, the pace of research is slowed down significantly by the limitations of current tools for evaluating complement-targeting therapeutics. Moreover, the effects of potential therapeutic agents on innate immune cells, like neutrophils, are not fully understood. Here, we employ microfluidic assays and measure chemotaxis, phagocytosis, and swarming changes in human neutrophils ex vivo in response to various complement-targeting agents. We show that whereas complement factor 5 (C5) cleavage inhibitor eculizumab blocks all neutrophil anti-microbial functions, newer compounds like the C5 cleavage inhibitor RA101295 and C5a receptor antagonist avacopan inhibit chemotaxis and swarming while preserving neutrophil phagocytosis. These results highlight the utility of microfluidic neutrophil assays in evaluating potential complement-targeting therapeutics.
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Affiliation(s)
- Sinan Muldur
- BioMEMS Resource Center, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.,Shriners Burns Hospital, Boston, MA, United States
| | | | | | - Yalan Tang
- Ra Pharmaceuticals, Inc., Cambridge, MA, United States
| | | | | | - Daniel Irimia
- BioMEMS Resource Center, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.,Shriners Burns Hospital, Boston, MA, United States
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Qiao S, Dennis M, Song X, Vadysirisack DD, Salunke D, Nash Z, Yang Z, Liesa M, Yoshioka J, Matsuzawa SI, Shirihai OS, Lee RT, Reed JC, Ellisen LW. A REDD1/TXNIP pro-oxidant complex regulates ATG4B activity to control stress-induced autophagy and sustain exercise capacity. Nat Commun 2015; 6:7014. [PMID: 25916556 PMCID: PMC4421852 DOI: 10.1038/ncomms8014] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 03/23/2015] [Indexed: 12/12/2022] Open
Abstract
Macroautophagy (autophagy) is a critical cellular stress response; however, the signal transduction pathways controlling autophagy induction in response to stress are poorly understood. Here we reveal a new mechanism of autophagy control whose deregulation disrupts mitochondrial integrity and energy homeostasis in vivo. Stress conditions including hypoxia and exercise induce reactive oxygen species (ROS) through upregulation of a protein complex involving REDD1, an mTORC1 inhibitor and the pro-oxidant protein TXNIP. Decreased ROS in cells and tissues lacking either REDD1 or TXNIP increases catalytic activity of the redox-sensitive ATG4B cysteine endopeptidase, leading to enhanced LC3B delipidation and failed autophagy. Conversely, REDD1/TXNIP complex expression is sufficient to induce ROS, suppress ATG4B activity and activate autophagy. In Redd1−/− mice, deregulated ATG4B activity and disabled autophagic flux cause accumulation of defective mitochondria, leading to impaired oxidative phosphorylation, muscle ATP depletion and poor exercise capacity. Thus, ROS regulation through REDD1/TXNIP is physiological rheostat controlling stress-induced autophagy. Stress-induced macroautophagy is initiated by the induction of reactive oxygen species (ROS). Here Qiao et al. show that the mTOR inhibitor REDD1 in a complex with pro-oxidant protein TXNIP induces ROS formation, leading to ATG4B suppression and autophagy activation in a largely mTOR-independent manner.
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Affiliation(s)
- Shuxi Qiao
- 1] Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA [2] Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Michael Dennis
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA
| | - Xiufeng Song
- 1] Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA [2] Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Douangsone D Vadysirisack
- 1] Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA [2] Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Devika Salunke
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA
| | - Zachary Nash
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA
| | - Zhifen Yang
- Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA
| | - Marc Liesa
- Department of Medicine, Evans Center, Mitochondria ARC, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Jun Yoshioka
- 1] Harvard Medical School, Boston, Massachusetts 02115, USA [2] Regenerative Medicine Center, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
| | - Shu-Ichi Matsuzawa
- Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA
| | - Orian S Shirihai
- 1] Department of Medicine, Evans Center, Mitochondria ARC, Boston University School of Medicine, Boston, Massachusetts 02118, USA [2] Department of Clinical Biochemistry, Faculty of Medicine, Ben Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Richard T Lee
- 1] Harvard Medical School, Boston, Massachusetts 02115, USA [2] Regenerative Medicine Center, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
| | - John C Reed
- 1] Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA [2] Roche Pharmaceutical Research and Early Development, Basel 4070, Switzerland
| | - Leif W Ellisen
- 1] Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA [2] Harvard Medical School, Boston, Massachusetts 02115, USA
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Ory B, Ramsey MR, Wilson C, Vadysirisack DD, Forster N, Rocco JW, Rothenberg SM, Ellisen LW. A microRNA-dependent program controls p53-independent survival and chemosensitivity in human and murine squamous cell carcinoma. J Clin Invest 2014. [DOI: 10.1172/jci75406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Abstract
The adaptive response to hypoxia, low oxygen tension, involves inhibition of energy-intensive cellular processes including protein translation. This effect is mediated in part through a decrease in the kinase activity of mammalian target of rapamycin complex 1 (mTORC1), a master regulator of protein translation. The principle mechanism for hypoxia-induced mTORC1 inhibition, however, was not elucidated until recently. Our work has demonstrated that the stress-induced protein REDD1 is essential for hypoxia regulation of mTORC1 activity and has further defined the molecular mechanism whereby REDD1 represses mTORC1 activity under hypoxic stress. Using our studies with REDD1 as an example, we describe in detail biochemical approaches to assess mTORC1 activity in the hypoxic response. Here, we provide methodologies to monitor signaling components both downstream and upstream of the hypoxia-induced mTORC1 inhibitory pathway. These methodologies will serve as valuable tools for researchers seeking to understand mTORC1 dysregulation in the context of hypoxic stress.
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Ory B, Ramsey MR, Wilson C, Vadysirisack DD, Forster N, Rocco JW, Rothenberg SM, Ellisen LW. A microRNA-dependent program controls p53-independent survival and chemosensitivity in human and murine squamous cell carcinoma. J Clin Invest 2011; 121:809-20. [PMID: 21293058 DOI: 10.1172/jci43897] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 11/10/2010] [Indexed: 12/19/2022] Open
Abstract
The p53 tumor suppressor, a central mediator of chemosensitivity in normal cells, is functionally inactivated in many human cancers. Therefore, a central challenge in human cancer therapy is the identification of pathways that control tumor cell survival and chemosensitivity in the absence of functional p53. The p53-related transcription factors p63 and p73 exhibit distinct functions—p73 mediates chemosensitivity while p63 promotes proliferation and cell survival—and are both overexpressed in squamous cell carcinomas (SCCs). However, how p63 and p73 interact functionally and govern the balance between prosurvival and proapoptotic programs in SCC remains elusive. Here, we identify a microRNA-dependent mechanism of p63/p73 crosstalk that regulates p53-independent survival of both human and murine SCC. We first discovered that a subset of p63-regulated microRNAs target p73 for inhibition. One of these, miR-193a-5p, expression of which was repressed by p63, was activated by proapoptotic p73 isoforms in both normal cells and tumor cells in vivo. Chemotherapy caused p63/p73-dependent induction of this microRNA, thereby limiting chemosensitivity due to microRNA-mediated feedback inhibition of p73. Importantly, inhibiting miR-193a interrupted this feedback and thereby suppressed tumor cell viability and induced dramatic chemosensitivity both in vitro and in vivo. Thus, we have identified a direct, microRNA-dependent regulatory circuit mediating inducible chemoresistance, whose inhibition may provide a new therapeutic opportunity in p53-deficient tumors.
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Affiliation(s)
- Benjamin Ory
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02114, USA
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Zhong L, D'Urso A, Toiber D, Sebastian C, Henry RE, Vadysirisack DD, Guimaraes A, Marinelli B, Wikstrom JD, Nir T, Clish CB, Vaitheesvaran B, Iliopoulos O, Kurland I, Dor Y, Weissleder R, Shirihai OS, Ellisen LW, Espinosa JM, Mostoslavsky R. The histone deacetylase Sirt6 regulates glucose homeostasis via Hif1alpha. Cell 2010; 140:280-93. [PMID: 20141841 DOI: 10.1016/j.cell.2009.12.041] [Citation(s) in RCA: 760] [Impact Index Per Article: 54.3] [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: 07/28/2009] [Revised: 10/27/2009] [Accepted: 12/21/2009] [Indexed: 12/15/2022]
Abstract
SIRT6 is a member of a highly conserved family of NAD(+)-dependent deacetylases with various roles in metabolism, stress resistance, and life span. SIRT6-deficient mice develop normally but succumb to a lethal hypoglycemia early in life; however, the mechanism underlying this hypoglycemia remained unclear. Here, we demonstrate that SIRT6 functions as a histone H3K9 deacetylase to control the expression of multiple glycolytic genes. Specifically, SIRT6 appears to function as a corepressor of the transcription factor Hif1alpha, a critical regulator of nutrient stress responses. Consistent with this notion, SIRT6-deficient cells exhibit increased Hif1alpha activity and show increased glucose uptake with upregulation of glycolysis and diminished mitochondrial respiration. Our studies uncover a role for the chromatin factor SIRT6 as a master regulator of glucose homeostasis and may provide the basis for novel therapeutic approaches against metabolic diseases, such as diabetes and obesity.
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Affiliation(s)
- Lei Zhong
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
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12
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Vadysirisack DD, Chen ESW, Zhang Z, Tsai MD, Chang GD, Jhiang SM. Identification of in vivo phosphorylation sites and their functional significance in the sodium iodide symporter. J Biol Chem 2007; 282:36820-8. [PMID: 17913707 DOI: 10.1074/jbc.m706817200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [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] [Indexed: 11/06/2022] Open
Abstract
The Na+/I- symporter (NIS)-mediated iodide uptake activity is the basis for targeted radioiodide ablation of thyroid cancers. Although it has been shown that NIS protein is phosphorylated, neither the in vivo phosphorylation sites nor their functional significance has been reported. In this study, Ser-43, Thr-49, Ser-227, Thr-577, and Ser-581 were identified as in vivo NIS phosphorylation sites by mass spectrometry. Kinetic analysis of NIS mutants of the corresponding phosphorylated amino acid residue indicated that the velocity of iodide transport of NIS is modulated by the phosphorylation status of Ser-43 and Ser-581. We also found that the phosphorylation status of Thr-577 may be important for NIS protein stability and that the phosphorylation status of Ser-227 is functionally silent. Thr-49 appears to be critical for proper local structure/conformation of NIS because mutation of Thr-49 to alanine, aspartic acid, or serine results in reduced NIS activity without alterations in total or cell surface NIS protein levels. Taken together, we showed that NIS protein levels and functional activity could be modulated by phosphorylation through distinct mechanisms.
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Affiliation(s)
- Douangsone D Vadysirisack
- Integrated Biomedical Science Graduate Program, Department of Physiology and Cell Biology, Ohio State University, Columbus 43210, USA
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Abstract
The Na(+)/I(-) symporter (NIS)-mediated iodide uptake is the basis for targeted radioiodine ablation of thyroid cancers. However, NIS-mediated radioiodide uptake (RAIU) activity is often reduced in thyroid cancers. As mitogen activated protein kinase (MAPK) signaling pathway is activated in about 70% of papillary thyroid carcinoma, we investigated whether MEK (MAPK kinase) inhibition will restore NIS protein levels and NIS-mediated RAIU activity in RET/PTC oncogene-transformed thyroid cells. We found that MEK inhibitor PD98059 increased NIS protein levels within 30 min of treatment. However, the increase of NIS protein level was not accompanied with an increase in NIS-mediated RAIU activity, particularly at early time points of PD98059 treatment. PD98059 also decreased RAIU activity mediated by exogenous NIS in non-thyroid cells. The transient decrease of RAIU activity by PD98059 in thyroid cells was not due to decreased NIS cell surface level, decreased NIS binding affinity for I(-) , or increased iodide efflux. While PD98059 moderately decreased Na(+)/K(+)-ATPase activity, ouabain titration indicates that the extent of decrease in Na(+)/K(+)-ATPase activity is much greater than the extent of decrease in RAIU activity. Additionally, a decrease of Na(+)/K(+)-ATPase activity was not accompanied with a decrease of biotin uptake activity mediated by Na(+)-dependent multivitamin transporter. Since PD98059 reduced V(max)- I(-) without decreasing NIS cell surface levels, it is most likely that PD98059 decreases the turnover rate of iodide transport with an yet to be identified mechanism.
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Affiliation(s)
- Douangsone D Vadysirisack
- Integrated Biomedical Science Graduate Program, The Ohio State University, Columbus, Ohio 43210, USA
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Vadysirisack DD, Shen DH, Jhiang SM. Correlation of Na+/I- symporter expression and activity: implications of Na+/I- symporter as an imaging reporter gene. J Nucl Med 2006; 47:182-90. [PMID: 16391203] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
UNLABELLED The Na(+)/I(-) symporter (NIS) has been proposed as an imaging reporter gene to ascertain the expression of therapeutic genes in targeted tissues. In this study, we investigated whether posttranslational processing and cell-surface trafficking of NIS affect NIS-mediated radioiodide uptake in cells expressing exogenous NIS. METHODS We established FTC133, HeLa, and PC12 cell lines with doxycycline-inducible NIS expression to investigate the correlation among total NIS protein levels, cell-surface NIS protein levels, and NIS-mediated radioiodide uptake in cells induced with various levels of NIS. RESULTS We found that most exogenous NIS proteins were efficiently trafficked to the cell surface; thus, a possible deficiency in NIS cell-surface trafficking is not a concern for clinical applications of NIS gene transfer. The extent of radioiodide uptake correlated with cell-surface NIS protein level within a certain range, suggesting that the imaging signals can quantify levels of NIS expression only within a certain range in vivo. Finally, a moderate increase in NIS protein level significantly increased radioiodide uptake, indicating that a low level of NIS expression is sufficient to facilitate radionuclide imaging in vivo. CONCLUSION Our study suggests that NIS will be useful as an imaging reporter gene to ascertain that the therapeutic gene is localized to the correct tissue and to monitor the expression levels and duration of the therapeutic gene.
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Marsee DK, Vadysirisack DD, Morrison CD, Prasad ML, Eng C, Duh QY, Rauen KA, Kloos RT, Jhiang SM. Variable expression of coxsackie-adenovirus receptor in thyroid tumors: implications for adenoviral gene therapy. Thyroid 2005; 15:977-87. [PMID: 16187905 DOI: 10.1089/thy.2005.15.977] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [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: 11/13/2022]
Abstract
Adenoviral gene therapy represents a novel approach for the treatment of aggressive thyroid carcinomas. Both coxsackie-adenovirus receptor (CAR) and integrins have been shown to be the major determinants for adenoviral infectivity in many types of cancer cells, yet conflicting results have been reported. In this report we examine these factors mediating adenoviral infection in thyroid cells and to evaluate CAR expression in various types of thyroid cancer. We found that neither expression levels of CAR nor integrins are solely predictive of adenoviral infectivity in thyroid cells. However, the absence of CAR was associated with poor adenoviral infectivity in immortalized rat FRTL-5 cells. Moreover, preincubation with alpha-CAR antibody decreased infectivity in FTC 238 cells, a human thyroid tumor line. These results indicate that CAR does play a role in adenoviral infection of thyroid cells. Immunohistochemical analysis revealed that CAR is expressed at the cell surface in the majority of malignant thyroid tumors. We further show that adenoviral infectivity in some thyroid cancer cells can be improved by poly-L-lysine. Our study warrants a functional method to evaluate adenoviral infectivity should be developed and instituted prior to clinical trials of adenoviral gene therapy in patients with advanced thyroid cancer.
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Affiliation(s)
- Derek K Marsee
- Medical Scientist Program, The Ohio State University, Columbus, Ohio, USA
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Morgenstern KE, Vadysirisack DD, Zhang Z, Cahill KV, Foster JA, Burns JA, Kloos RT, Jhiang SM. Expression of Sodium Iodide Symporter in the Lacrimal Drainage System: Implication for the Mechanism Underlying Nasolacrimal Duct Obstruction in I131-Treated Patients. Ophthalmic Plast Reconstr Surg 2005; 21:337-44. [PMID: 16234694 DOI: 10.1097/01.iop.0000179369.75569.a8] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [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] [Indexed: 11/25/2022]
Abstract
PURPOSE Nasolacrimal outflow obstruction has been associated with high-dose (>150 mCi) radioactive iodine (I(131)) treatment. Commonly used for thyroid cancer treatment, I(131) is effectively transported in the targeted tissue by the Na(+)/I symporter (NIS). We hypothesized that NIS is expressed in the lacrimal sac and nasolacrimal duct and that active accumulation of I(131) is responsible for the clinical observations seen in these patients. METHODS Reverse transcriptase-polymerase chain reaction and immunohistochemical analyses were used to evaluate NIS expression in both archived and fresh human tissues RESULTS Reverse transcriptase-polymerase chain reaction analysis showed that NIS mRNA is present in the lacrimal sac. Immunohistochemical analysis indicated that NIS protein is expressed in the stratified columnar epithelial cells of the lacrimal sac and nasolacrimal duct. NIS protein was undetectable in the lacrimal gland, Wolfring and Krause glands, conjunctiva, canaliculus, and nasal mucosa. NIS-expressing columnar epithelial cells were absent and fibrosis was evident in the lacrimal sacs from I(131)-treated patients undergoing dacryocystorhinostomy. CONCLUSIONS NIS is present in the lacrimal sac and nasolacrimal duct of humans, correlating to the anatomic areas of clinical obstruction that develop in patients treated with greater than 150 mCi of I(131). This suggests that NIS may be the vector of radiation-induced injury to the lacrimal system. To our knowledge, this is the first report of any ion transporter in the nasolacrimal outflow system and raises new questions as to the role the lacrimal sac plays in the modification of tears and in lacrimal outflow pathology.
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Affiliation(s)
- Kenneth E Morgenstern
- Department of Ophthalmology, Division of Oculoplastic Surgery, The Ohio State University, Columbus, OH, USA.
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Marsee DK, Shen DHY, MacDonald LR, Vadysirisack DD, Lin X, Hinkle G, Kloos RT, Jhiang SM. Imaging of metastatic pulmonary tumors following NIS gene transfer using single photon emission computed tomography. Cancer Gene Ther 2004; 11:121-7. [PMID: 14730332 DOI: 10.1038/sj.cgt.7700661] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [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] [Indexed: 11/09/2022]
Abstract
The Na+/I- symporter (NIS) is a membrane glycoprotein that facilitates the uptake of iodine into thyroid follicular cells. Recently, we and others have demonstrated the feasibility of imaging subcutaneous xenografts expressing exogenous NIS, suggesting that NIS may serve as an imaging reporter gene to monitor vector delivery and therapeutic gene expression. In this study, we established NIS-expressing pulmonary tumors in nude mice to investigate the minimal tumor size required for in vivo detection of pulmonary tumors by single photon emission computed tomography (SPECT) with pinhole collimation. In order to define the anatomic location of NIS-expressing tumor nodules detectable by SPECT, we performed simultaneous, dual-isotope imaging. We injected 1 mCi 99mTc-MAA via tail vein to image pulmonary perfusion and injected 1 mCi Na125I intraperitoneally to image NIS-expressing tumors. Fused images showed that 99mTc-MAA perfusion defects correlated with NIS-mediated 125I uptake. Post-mortem analysis revealed that tumors 3 mm in diameter could be detected by SPECT with pinhole collimation. These studies demonstrate the feasibility of SPECT to detect pulmonary tumors expressing exogenous NIS in mice.
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Affiliation(s)
- Derek K Marsee
- Medical Scientist Program, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio 43210, USA
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