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Wang Z, Li W, Jiang Y, Park J, Gonzalez KM, Wu X, Zhang QY, Lu J. Cholesterol-modified sphingomyelin chimeric lipid bilayer for improved therapeutic delivery. Nat Commun 2024; 15:2073. [PMID: 38453918 PMCID: PMC10920917 DOI: 10.1038/s41467-024-46331-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/22/2024] [Indexed: 03/09/2024] Open
Abstract
Cholesterol (Chol) fortifies packing and reduces fluidity and permeability of the lipid bilayer in vesicles (liposomes)-mediated drug delivery. However, under the physiological environment, Chol is rapidly extracted from the lipid bilayer by biomembranes, which jeopardizes membrane stability and results in premature leakage for delivered payloads, yielding suboptimal clinic efficacy. Herein, we report a Chol-modified sphingomyelin (SM) lipid bilayer via covalently conjugating Chol to SM (SM-Chol), which retains membrane condensing ability of Chol. Systemic structure activity relationship screening demonstrates that SM-Chol with a disulfide bond and longer linker outperforms other counterparts and conventional phospholipids/Chol mixture systems on blocking Chol transfer and payload leakage, increases maximum tolerated dose of vincristine while reducing systemic toxicities, improves pharmacokinetics and tumor delivery efficiency, and enhances antitumor efficacy in SU-DHL-4 diffuse large B-cell lymphoma xenograft model in female mice. Furthermore, SM-Chol improves therapeutic delivery of structurally diversified therapeutic agents (irinotecan, doxorubicin, dexamethasone) or siRNA targeting multi-drug resistant gene (p-glycoprotein) in late-stage metastatic orthotopic KPC-Luc pancreas cancer, 4T1-Luc2 triple negative breast cancer, lung inflammation, and CT26 colorectal cancer animal models in female mice compared to respective FDA-approved nanotherapeutics or lipid compositions. Thus, SM-Chol represents a promising platform for universal and improved drug delivery.
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Affiliation(s)
- Zhiren Wang
- Skaggs Pharmaceutical Sciences Center, Department of Pharmacology & Toxicology, R. Ken Coit College of Pharmacy, The University of Arizona, Tucson, AZ, 85721, USA
| | - Wenpan Li
- Skaggs Pharmaceutical Sciences Center, Department of Pharmacology & Toxicology, R. Ken Coit College of Pharmacy, The University of Arizona, Tucson, AZ, 85721, USA
| | - Yanhao Jiang
- Skaggs Pharmaceutical Sciences Center, Department of Pharmacology & Toxicology, R. Ken Coit College of Pharmacy, The University of Arizona, Tucson, AZ, 85721, USA
| | - Jonghan Park
- Skaggs Pharmaceutical Sciences Center, Department of Pharmacology & Toxicology, R. Ken Coit College of Pharmacy, The University of Arizona, Tucson, AZ, 85721, USA
| | - Karina Marie Gonzalez
- Skaggs Pharmaceutical Sciences Center, Department of Pharmacology & Toxicology, R. Ken Coit College of Pharmacy, The University of Arizona, Tucson, AZ, 85721, USA
| | - Xiangmeng Wu
- Skaggs Pharmaceutical Sciences Center, Department of Pharmacology & Toxicology, R. Ken Coit College of Pharmacy, The University of Arizona, Tucson, AZ, 85721, USA
| | - Qing-Yu Zhang
- Skaggs Pharmaceutical Sciences Center, Department of Pharmacology & Toxicology, R. Ken Coit College of Pharmacy, The University of Arizona, Tucson, AZ, 85721, USA
- Southwest Environmental Health Sciences Center, The University of Arizona, Tucson, 85721, USA
| | - Jianqin Lu
- Skaggs Pharmaceutical Sciences Center, Department of Pharmacology & Toxicology, R. Ken Coit College of Pharmacy, The University of Arizona, Tucson, AZ, 85721, USA.
- Southwest Environmental Health Sciences Center, The University of Arizona, Tucson, 85721, USA.
- Clinical and Translational Oncology Program (CTOP), The University of Arizona Cancer Center, Tucson, AZ, 85721, USA.
- BIO5 Institute, The University of Arizona, Tucson, AZ, 85721, USA.
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2
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Hammad SM, Lopes-Virella MF. Circulating Sphingolipids in Insulin Resistance, Diabetes and Associated Complications. Int J Mol Sci 2023; 24:14015. [PMID: 37762318 PMCID: PMC10531201 DOI: 10.3390/ijms241814015] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Sphingolipids play an important role in the development of diabetes, both type 1 and type 2 diabetes, as well as in the development of both micro- and macro-vascular complications. Several reviews have been published concerning the role of sphingolipids in diabetes but most of the emphasis has been on the possible mechanisms by which sphingolipids, mainly ceramides, contribute to the development of diabetes. Research on circulating levels of the different classes of sphingolipids in serum and in lipoproteins and their importance as biomarkers to predict not only the development of diabetes but also of its complications has only recently emerged and it is still in its infancy. This review summarizes the previously published literature concerning sphingolipid-mediated mechanisms involved in the development of diabetes and its complications, focusing on how circulating plasma sphingolipid levels and the relative content carried by the different lipoproteins may impact their role as possible biomarkers both in the development of diabetes and mainly in the development of diabetic complications. Further studies in this field may open new therapeutic avenues to prevent or arrest/reduce both the development of diabetes and progression of its complications.
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Affiliation(s)
- Samar M. Hammad
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Maria F. Lopes-Virella
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
- Ralph H. Johnson VA Medical Center, Charleston, SC 29425, USA
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3
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Guo Z, Kasinathan D, Merriman C, Nakayama M, Li H, Li H, Xu C, Wong GW, Yu L, Golson ML, Fu D. Cell-Surface Autoantibody Targets Zinc Transporter-8 (ZnT8) for In Vivo β-Cell Imaging and Islet-Specific Therapies. Diabetes 2023; 72:184-195. [PMID: 36448936 PMCID: PMC9876881 DOI: 10.2337/db22-0477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 11/07/2022] [Indexed: 12/02/2022]
Abstract
Type 1 diabetes (T1D) is a disease in which autoimmune attacks are directed at the insulin-producing β-cell in the pancreatic islet. Autoantigens on the β-cell surface membrane are specific markers for molecular recognition and targets for engagement by autoreactive B lymphocytes, which produce islet cell surface autoantibody (ICSA) upon activation. We report the cloning of an ICSA (mAb43) that recognizes a major T1D autoantigen, ZnT8, with a subnanomolar binding affinity and conformation specificity. We demonstrate that cell-surface binding of mAb43 protects the extracellular epitope of ZnT8 against immunolabeling by serum ICSA from a patient with T1D. Furthermore, mAb43 exhibits in vitro and ex vivo specificity for islet cells, mirroring the exquisite specificity of islet autoimmunity in T1D. Systemic administration of mAb43 yields a pancreas-specific biodistribution in mice and islet homing of an mAb43-linked imaging payload through the pancreatic vasculature, thereby validating the in vivo specificity of mAb43. Identifying ZnT8 as a major antigenic target of ICSA allows for research into the molecular recognition and engagement of autoreactive B cells in the chronic phase of T1D progression. The in vivo islet specificity of mAb43 could be further exploited to develop in vivo imaging and islet-specific immunotherapies.
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Affiliation(s)
- Zheng Guo
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, MD
| | - Devi Kasinathan
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, MD
| | - Chengfeng Merriman
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, MD
| | - Maki Nakayama
- Barbara Davis Center for Diabetes, University of Colorado, Aurora, CO
| | - Hua Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI
| | - Cheng Xu
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, MD
| | - G. William Wong
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, MD
| | - Liping Yu
- Barbara Davis Center for Diabetes, University of Colorado, Aurora, CO
| | - Maria L. Golson
- Division of Endocrinology, Diabetes, and Metabolism, Johns Hopkins School of Medicine, Baltimore, MD
| | - Dax Fu
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, MD
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4
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Kobayashi T, Tomishige N, Inaba T, Makino A, Murata M, Yamaji-Hasegawa A, Murate M. Impact of Intrinsic and Extrinsic Factors on Cellular Sphingomyelin Imaging with Specific Reporter Proteins. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2021; 4:25152564211042456. [PMID: 37366372 PMCID: PMC10259817 DOI: 10.1177/25152564211042456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
Sphingomyelin (SM) is a major sphingolipid in mammalian cells. Although SM is enriched in the outer leaflet of the cell plasma membrane, lipids are also observed in the inner leaflet of the plasma membrane and intracellular organelles such as endolysosomes, the Golgi apparatus and nuclei. SM is postulated to form clusters with glycosphingolipids (GSLs), cholesterol (Chol), and other SM molecules through hydrophobic interactions and hydrogen bonding. Thus, different clusters composed of SM, SM/Chol, SM/GSL and SM/GSL/Chol with different stoichiometries may exist in biomembranes. In addition, SM monomers may be located in the glycerophospholipid-rich areas of membranes. Recently developed SM-binding proteins (SBPs) distinguish these different SM assemblies. Here, we summarize the effects of intrinsic factors regulating the lipid-binding specificity of SBPs and extrinsic factors, such as the lipid phase and lipid density, on SM recognition by SBPs. The combination of different SBPs revealed the heterogeneity of SM domains in biomembranes.
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Affiliation(s)
- Toshihide Kobayashi
- Lipid Biology Laboratory, RIKEN, Wako, Saitama, Japan
- Cellular Informatics Laboratory, RIKEN
CPR, Wako, Saitama, Japan
- Laboratoire de Bioimagerie et
Pathologies, Faculté de Pharmacie, UMR 7021 CNRS, Université de Strasbourg,
Illkirch, France
| | - Nario Tomishige
- Lipid Biology Laboratory, RIKEN, Wako, Saitama, Japan
- Cellular Informatics Laboratory, RIKEN
CPR, Wako, Saitama, Japan
- Laboratoire de Bioimagerie et
Pathologies, Faculté de Pharmacie, UMR 7021 CNRS, Université de Strasbourg,
Illkirch, France
| | | | - Asami Makino
- Lipid Biology Laboratory, RIKEN, Wako, Saitama, Japan
| | - Michio Murata
- Department of Chemistry, Graduate
School of Science, Osaka University, Toyonaka, Osaka, Japan
- ERATO, Lipid Active Structure Project,
Japan Science and Technology Agency, Graduate School of Science, Osaka University,
Osaka, Japan
| | | | - Motohide Murate
- Lipid Biology Laboratory, RIKEN, Wako, Saitama, Japan
- Cellular Informatics Laboratory, RIKEN
CPR, Wako, Saitama, Japan
- Laboratoire de Bioimagerie et
Pathologies, Faculté de Pharmacie, UMR 7021 CNRS, Université de Strasbourg,
Illkirch, France
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5
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Sphingolipids in Type 1 Diabetes: Focus on Beta-Cells. Cells 2020; 9:cells9081835. [PMID: 32759843 PMCID: PMC7465050 DOI: 10.3390/cells9081835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/01/2020] [Accepted: 08/03/2020] [Indexed: 12/28/2022] Open
Abstract
Type 1 diabetes (T1DM) is a chronic autoimmune disease, with a strong genetic background, leading to a gradual loss of pancreatic beta-cells, which secrete insulin and control glucose homeostasis. Patients with T1DM require life-long substitution with insulin and are at high risk for development of severe secondary complications. The incidence of T1DM has been continuously growing in the last decades, indicating an important contribution of environmental factors. Accumulating data indicates that sphingolipids may be crucially involved in T1DM development. The serum lipidome of T1DM patients is characterized by significantly altered sphingolipid composition compared to nondiabetic, healthy probands. Recently, several polymorphisms in the genes encoding the enzymatic machinery for sphingolipid production have been identified in T1DM individuals. Evidence gained from studies in rodent islets and beta-cells exposed to cytokines indicates dysregulation of the sphingolipid biosynthetic pathway and impaired function of several sphingolipids. Moreover, a number of glycosphingolipids have been suggested to act as beta-cell autoantigens. Studies in animal models of autoimmune diabetes, such as the Non Obese Diabetic (NOD) mouse and the LEW.1AR1-iddm (IDDM) rat, indicate a crucial role of sphingolipids in immune cell trafficking, islet infiltration and diabetes development. In this review, the up-to-date status on the findings about sphingolipids in T1DM will be provided, the under-investigated research areas will be identified and perspectives for future studies will be given.
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6
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Neo CWY, Ciaramicoli LM, Soetedjo AAP, Teo AKK, Kang NY. A new perspective of probe development for imaging pancreatic beta cell in vivo. Semin Cell Dev Biol 2020; 103:3-13. [PMID: 32057664 DOI: 10.1016/j.semcdb.2020.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/20/2020] [Accepted: 01/28/2020] [Indexed: 12/23/2022]
Abstract
Beta cells assume a fundamental role in maintaining blood glucose homeostasis through the secretion of insulin, which is contingent on both beta cell mass and function, in response to elevated blood glucose levels or secretagogues. For this reason, evaluating beta cell mass and function, as well as scrutinizing how they change over time in a diabetic state, are essential prerequisites in elucidating diabetes pathophysiology. Current clinical methods to measure human beta cell mass and/or function are largely lacking, indirect and sub-optimal, highlighting the continued need for noninvasive in vivo beta cell imaging technologies such as optical imaging techniques. While numerous probes have been developed and evaluated for their specificity to beta cells, most of them are more suited to visualize beta cell mass rather than function. In this review, we highlight the distinction between beta cell mass and function, and the importance of developing more probes to measure beta cell function. Additionally, we also explore various existing probes that can be employed to measure beta cell mass and function in vivo, as well as the caveats in probe development for in vivo beta cell imaging.
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Affiliation(s)
- Claire Wen Ying Neo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), A*STAR, Singapore, 138673, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596, Singapore
| | - Larissa Miasiro Ciaramicoli
- Department of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Andreas Alvin Purnomo Soetedjo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), A*STAR, Singapore, 138673, Singapore
| | - Adrian Kee Keong Teo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), A*STAR, Singapore, 138673, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596, Singapore.
| | - Nam-Young Kang
- Department of Creative IT Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Namgu, C5 Building, Room 203, Pohang, Kyungbuk, 37673, Republic of Korea.
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7
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Jodal A, Schibli R, Béhé M. Targets and probes for non-invasive imaging of β-cells. Eur J Nucl Med Mol Imaging 2016; 44:712-727. [PMID: 28025655 PMCID: PMC5323463 DOI: 10.1007/s00259-016-3592-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 12/01/2016] [Indexed: 12/16/2022]
Abstract
β-cells, located in the islets of the pancreas, are responsible for production and secretion of insulin and play a crucial role in blood sugar regulation. Pathologic β-cells often cause serious medical conditions affecting blood glucose level, which severely impact life quality and are life-threatening if untreated. With 347 million patients, diabetes is one of the most prevalent diseases, and will continue to be one of the largest socioeconomic challenges in the future. The diagnosis still relies mainly on indirect methods like blood sugar measurements. A non-invasive diagnostic imaging modality would allow direct evaluation of β-cell mass and would be a huge step towards personalized medicine. Hyperinsulinism is another serious condition caused by β-cells that excessively secrete insulin, like for instance β-cell hyperplasia and insulinomas. Treatment options with drugs are normally not curative, whereas curative procedures usually consist of the resection of affected regions for which, however, an exact localization of the foci is necessary. In this review, we describe potential tracers under development for targeting β-cells with focus on radiotracers for PET and SPECT imaging, which allow the non-invasive visualization of β-cells. We discuss either the advantages or limitations for the various tracers and modalities. This article concludes with an outlook on future developments and discuss the potential of new imaging probes including dual probes that utilize functionalities for both a radioactive and optical moiety as well as for theranostic applications.
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Affiliation(s)
- Andreas Jodal
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Roger Schibli
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institut, 5232, Villigen, Switzerland.,Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Martin Béhé
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institut, 5232, Villigen, Switzerland.
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8
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Laurent D, Vinet L, Lamprianou S, Daval M, Filhoulaud G, Ktorza A, Wang H, Sewing S, Juretschke HP, Glombik H, Meda P, Boisgard R, Nguyen DL, Stasiuk GJ, Long NJ, Montet X, Hecht P, Kramer W, Rutter GA, Hecksher-Sørensen J. Pancreatic β-cell imaging in humans: fiction or option? Diabetes Obes Metab 2016; 18:6-15. [PMID: 26228188 DOI: 10.1111/dom.12544] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 07/02/2015] [Accepted: 07/28/2015] [Indexed: 01/02/2023]
Abstract
Diabetes mellitus is a growing worldwide epidemic disease, currently affecting 1 in 12 adults. Treatment of disease complications typically consumes ∼10% of healthcare budgets in developed societies. Whilst immune-mediated destruction of insulin-secreting pancreatic β cells is responsible for Type 1 diabetes, both the loss and dysfunction of these cells underly the more prevalent Type 2 diabetes. The establishment of robust drug development programmes aimed at β-cell restoration is still hampered by the absence of means to measure β-cell mass prospectively in vivo, an approach which would provide new opportunities for understanding disease mechanisms and ultimately assigning personalized treatments. In the present review, we describe the progress towards this goal achieved by the Innovative Medicines Initiative in Diabetes, a collaborative public-private consortium supported by the European Commission and by dedicated resources of pharmaceutical companies. We compare several of the available imaging methods and molecular targets and provide suggestions as to the likeliest to lead to tractable approaches. Furthermore, we discuss the simultaneous development of animal models that can be used to measure subtle changes in β-cell mass, a prerequisite for validating the clinical potential of the different imaging tracers.
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Affiliation(s)
- D Laurent
- Biomarker Department, Clinical Imaging, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - L Vinet
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland
| | - S Lamprianou
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland
| | - M Daval
- Metabolic Diseases Department, Servier Research Institute, Suresnes, France
| | - G Filhoulaud
- Metabolic Diseases Department, Servier Research Institute, Suresnes, France
| | - A Ktorza
- Metabolic Diseases Department, Servier Research Institute, Suresnes, France
| | - H Wang
- Roche Pharma Research and Early Development, Innovation Center Basel, Basel, Switzerland
| | - S Sewing
- Roche Pharma Research and Early Development, Innovation Center Basel, Basel, Switzerland
| | - H-P Juretschke
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - H Glombik
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - P Meda
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - R Boisgard
- Commissariat à l'Energie Atomique, Equipe d'Imagerie Moléculaire Expérimentale, Orsay, France
| | - D L Nguyen
- Commissariat à l'Energie Atomique, Equipe d'Imagerie Moléculaire Expérimentale, Orsay, France
| | - G J Stasiuk
- Department of Chemistry, Imperial College London, London, UK
| | - N J Long
- Department of Chemistry, Imperial College London, London, UK
| | - X Montet
- Department of Radiology, Geneva University Hospital, Geneva, Switzerland
| | - P Hecht
- IMIDIA Project Office, Graz, Austria
| | - W Kramer
- Scientific Consultant for Sanofi Deutschland GmbH, Frankfurt am Main, Germany
| | - G A Rutter
- Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial Centre for Translational and Experimental Medicine, Imperial College London, Hammersmith Hospital, London, UK
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9
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Wang P, Moore A. Theranostic MRI: the future for Type 1 diabetes management? ACTA ACUST UNITED AC 2014. [DOI: 10.2217/iim.13.67] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Sørensen JØ, Buschard K, Brogren CH. The preventive role of type 2 NKT cells in the development of type 1 diabetes. APMIS 2013; 122:167-82. [PMID: 23992281 DOI: 10.1111/apm.12140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 05/22/2013] [Indexed: 12/20/2022]
Abstract
In the last two decades, natural killer T (NKT) cells have emerged as an important factor in preventing type 1 diabetes (T1D) when investigated in the experimental non-obese diabetic (NOD) mouse model. So far, investigations have largely focused on type 1 NKT cells with invariant T-cell receptors, whereas the role of type 2 NKT cells with diverse T-cell receptors is less well understood. However, there have been several findings which indicate that in fact type 2 NKT cells may regulate the progression of type 1 diabetes in NOD mice, including a fraction of these cells which recognize β-cell-enriched sulfatide. Therefore, the focus for this review is to present the current evidence of the effect of type 2 NKT cells on the development of T1D. In general, there is still uncertainty surrounding the mechanism of activation and function of NKT cells. Here, we present two models of the effector mechanisms, respectively, Th1/Th2 polarization and the induction of tolerogenic dendritic cells (DC). In conclusion, this review points to the importance of immunoregulation by type 2 NKT cells in preventing the development of T1D and highlights the induction of tolerogenic DC as a likely mechanism. The possible therapeutic role of type 1 and type 2 NKT cells are evaluated and future experiments concerning type 2 NKT cells and T1D are proposed.
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Affiliation(s)
- Jakob Ørskov Sørensen
- The Bartholin Institute, Rigshospitalet, Copenhagen Biocenter, Ole Maaloesvej 5, Copenhagen, Denmark
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11
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Kavishwar A, Moore A. Sphingomyelin patches on pancreatic beta-cells are indicative of insulin secretory capacity. J Histochem Cytochem 2013; 61:910-9. [PMID: 23920110 DOI: 10.1369/0022155413502792] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The establishment and validation of specific markers on the surfaces of pancreatic beta-cells would have a significant impact on the development of agents that specifically target these cells for imaging and/or image-guided therapy in diabetes patient samples. We have recently described unique, cholesterol-stabilized sphingomyelin (SM) patches on the surfaces of beta-cells using the IC2 antibody. To further investigate the utility of SM patches as a unique beta-cell biomarker, we embarked on the current study to correlate the expression of this antigen with the insulin secretory capacity of beta-cells in tissue samples from patients and animals with type 1 and type 2 diabetes and compared this with samples from normal subjects. We found that the locations of SM patches were consistent with the insulin status of islets in all tissues studied. Using immunohistochemistry and staining with an IC2 antibody, we demonstrated a direct correlation between the reduced expression of SM patches and insulin production in diabetic individuals, indicating that the former could potentially serve as a functional biomarker of beta-cells. We believe that our results have significant implications for the further development of ligands with SM specificity for the non-invasive functional assessment of beta-cells and/or for targeted therapeutic delivery in diabetic patients.
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Affiliation(s)
- Amol Kavishwar
- Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Charlestown, MA (AK, AM)
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12
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Abstract
Recent technical advances have re-invigorated the study of sphingolipid metabolism in general, and helped to highlight the varied and important roles that sphingolipids play in pancreatic β-cells. Sphingolipid metabolites such as ceramide, glycosphingolipids, sphingosine 1-phosphate and gangliosides modulate many β-cell signaling pathways and processes implicated in β-cell diabetic disease such as apoptosis, β-cell cytokine secretion, ER-to-golgi vesicular trafficking, islet autoimmunity and insulin gene expression. They are particularly relevant to lipotoxicity. Moreover, the de novo synthesis of sphingolipids occurs on many subcellular membranes, in parallel to secretory vesicle formation, traffic and granule maturation events. Indeed, the composition of the plasma membrane, determined by the activity of neutral sphingomyelinases, affects β-cell excitability and potentially insulin exocytosis while another glycosphingolipid, sulfatide, determines the stability of insulin crystals in granules. Most importantly, sphingolipid metabolism on internal membranes is also strongly implicated in regulating β-cell apoptosis.
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Affiliation(s)
- Ebru Boslem
- Diabetes and Obesity Program; Garvan Institute of Medical Research; Darlinghurst, NSW Australia
- St Vincent’s Clinical School; Faculty of Medicine; University of New South Wales; Sydney, NSW Australia
| | - Peter J. Meikle
- Baker IDI Heart and Diabetes Institute; Melbourne, VIC Australia
| | - Trevor J. Biden
- Diabetes and Obesity Program; Garvan Institute of Medical Research; Darlinghurst, NSW Australia
- St Vincent’s Clinical School; Faculty of Medicine; University of New South Wales; Sydney, NSW Australia
- Correspondence to: Trevor J. Biden,
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