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Deshmukh A, Chang K, Cuala J, Vanslembrouck B, Georgia S, Loconte V, White KL. Subcellular Feature-Based Classification of α and β Cells Using Soft X-ray Tomography. Cells 2024; 13:869. [PMID: 38786091 PMCID: PMC11119489 DOI: 10.3390/cells13100869] [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: 04/26/2024] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 05/25/2024] Open
Abstract
The dysfunction of α and β cells in pancreatic islets can lead to diabetes. Many questions remain on the subcellular organization of islet cells during the progression of disease. Existing three-dimensional cellular mapping approaches face challenges such as time-intensive sample sectioning and subjective cellular identification. To address these challenges, we have developed a subcellular feature-based classification approach, which allows us to identify α and β cells and quantify their subcellular structural characteristics using soft X-ray tomography (SXT). We observed significant differences in whole-cell morphological and organelle statistics between the two cell types. Additionally, we characterize subtle biophysical differences between individual insulin and glucagon vesicles by analyzing vesicle size and molecular density distributions, which were not previously possible using other methods. These sub-vesicular parameters enable us to predict cell types systematically using supervised machine learning. We also visualize distinct vesicle and cell subtypes using Uniform Manifold Approximation and Projection (UMAP) embeddings, which provides us with an innovative approach to explore structural heterogeneity in islet cells. This methodology presents an innovative approach for tracking biologically meaningful heterogeneity in cells that can be applied to any cellular system.
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Affiliation(s)
- Aneesh Deshmukh
- Department of Chemistry, Bridge Institute, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA; (A.D.); (K.C.)
| | - Kevin Chang
- Department of Chemistry, Bridge Institute, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA; (A.D.); (K.C.)
| | - Janielle Cuala
- Department of Chemistry, Bridge Institute, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA; (A.D.); (K.C.)
- Medical Biophysics Program, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Bieke Vanslembrouck
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Senta Georgia
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Valentina Loconte
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Kate L. White
- Department of Chemistry, Bridge Institute, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA; (A.D.); (K.C.)
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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2
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Mallik R, Saha M, Singh V, Mohan H, Kumaran SS, Mukherjee C. Mn(II) complex impregnated porous silica nanoparticles as Zn(II)-responsive "Smart" MRI contrast agent for pancreas imaging. J Mater Chem B 2023; 11:8251-8261. [PMID: 37575086 DOI: 10.1039/d3tb01289a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Type-1 and type-2 diabetes mellitus are metabolic disorders governed by the functional efficiency of pancreatic β-cells. The activities of the cells toward insulin production, storage, and secretion are accompanied by Zn(II) ions. Thus, for non-invasive pathology of the cell, developing Zn(II) ion-responsive MRI-contrast agents has earned considerable interest. In this report, we have synthesized a seven-coordinate, mono(aquated) Mn(II) complex (1), which is impregnated within a porous silica nanosphere of size 13.2 nm to engender the Mn(II)-based MRI contrast agent, complex 1@SiO2NP. The surface functionalization of the nanosphere by the Py2Pic organic moiety for the selective binding of Zn(II)-ions yields complex 1@SiO2-Py2PicNP, which exhibits r1 = 13.19 mM-1 s-1. The relaxivity value elevates to 20.38 mM-1 s-1 in the presence of 0.6 mM BSA protein at pH 7.4. Gratifyingly, r1 increases linearly with the increase of Zn(II) ion concentration and reaches 39.01 mM-1 s-1 in the presence of a 40 fold excess of the ions. Thus, Zn(II)-responsive contrast enhancement in vivo is envisaged by employing the nanoparticle. Indeed, a contrast enhancement in the pancreas is observed when complex 1@SiO2-Py2PicNP and a glucose stimulus are administered in fasted healthy C57BL/6 mice at 7 T.
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Affiliation(s)
- Riya Mallik
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039 Assam, India.
| | - Muktashree Saha
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Vandna Singh
- Department of Medical Biotechnology, Maharshi Dayanand University, Rohtak, 124001, Haryana, India
| | - Hari Mohan
- Department of Medical Biotechnology, Maharshi Dayanand University, Rohtak, 124001, Haryana, India
| | - S Senthil Kumaran
- Department of NMR, All India Institute of Medical Sciences, Ansari Nagar, 110029, New Delhi, India
| | - Chandan Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039 Assam, India.
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3
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Bealer E, Crumley K, Clough D, King J, Behrend M, Annulis C, Li F, Soleimanpour S, Shea LD. Extrahepatic transplantation of 3D cultured stem cell-derived islet organoids on microporous scaffolds. Biomater Sci 2023; 11:3645-3655. [PMID: 37017294 PMCID: PMC10192035 DOI: 10.1039/d3bm00217a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
Stem cell differentiation methods have been developed to produce cells capable of insulin secretion which are showing promise in clinical trials for treatment of type-1 diabetes. Nevertheless, opportunities remain to improve cell maturation and function. Three-dimensional (3D) culture has demonstrated improved differentiation and metabolic function in organoid systems, with biomaterial scaffolds employed to direct cell assembly and facilitate cell-cell contacts. Herein, we investigate 3D culture of human stem cell-derived islet organoids, with 3D culture initiated at the pancreatic progenitor, endocrine progenitor, or immature β-cell stage. Clusters formed by reaggregation of immature β-cells could be readily seeded into the microporous poly(lactide-co-glycolide) scaffold, with control over cell number. Culture of islet organoids on scaffolds at the early to mid-stage beta cell progenitors had improved in vitro glucose stimulated insulin secretion relative to organoids formed at the pancreatic progenitor stage. Reaggregated islet organoids were transplanted into the peritoneal fat of streptozotocin-induced diabetic mice, which resulted in reduced blood glucose levels and the presence of systemic human C-peptide. In conclusion, 3D cell culture supports development of islet organoids as indicated by insulin secretion in vitro and supports transplantation to extrahepatic sites that leads to a reduction of hyperglycemia in vivo.
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Affiliation(s)
- Elizabeth Bealer
- Department of Biomedical Engineering, University of Michigan, 1119 Carl A. Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA.
| | - Kelly Crumley
- Department of Biomedical Engineering, University of Michigan, 1119 Carl A. Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA.
| | - Daniel Clough
- Department of Biomedical Engineering, University of Michigan, 1119 Carl A. Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA.
| | - Jessica King
- Department of Biomedical Engineering, University of Michigan, 1119 Carl A. Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA.
| | - Maya Behrend
- Department of Biomedical Engineering, University of Michigan, 1119 Carl A. Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA.
| | - Connor Annulis
- Department of Biomedical Engineering, University of Michigan, 1119 Carl A. Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA.
| | - Feiran Li
- Department of Biomedical Engineering, University of Michigan, 1119 Carl A. Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA.
| | - Scott Soleimanpour
- Department of Internal Medicine and Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Medicine Service, Endocrinology and Metabolism Section, VA Ann Arbor Health Care System, Ann Arbor, MI, USA
| | - Lonnie D Shea
- Department of Biomedical Engineering, University of Michigan, 1119 Carl A. Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA.
- Department of Surgery, University of Michigan, USA
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4
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Stefanov BA, Mansouri M, Charpin-El Hamri G, Fussenegger M. Sunlight-Controllable Biopharmaceutical Production for Remote Emergency Supply of Directly Injectable Therapeutic Proteins. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2202566. [PMID: 36084222 DOI: 10.1002/smll.202202566] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/12/2022] [Indexed: 06/15/2023]
Abstract
Biopharmaceutical manufacturing requires specialized facilities and a long-range cold supply chain for the delivery of the therapeutics to patients. In order to produce biopharmaceuticals in locations lacking such infrastructure, a production process is designed that utilizes the trigger-inducible release of large quantities of a stored therapeutic protein from engineered endocrine cells within minutes to generate a directly injectable saline solution of the protein. To illustrate the versatility of this approach, it is shown that not only insulin, but also glucagon-like peptide 1 (GLP-1), nanoluciferase (NLuc), and the model biopharmaceutical erythropoietin (EPO) can be trigger-inducibly released, even when using biologically inactive insulin as a carrier. The facilitating beta cells are engineered with a controllable TRPV1-mediated Ca2+ influx that induces the fusion of cytoplasmic storage vesicles with the membrane, leading to the release of the stored protein. When required, the growth medium is exchanged for saline solution, and the system is stimulated with the small molecule capsaicin, with a hand-warming pack, or simply by using sunlight. Injection of insulin saline solution obtained in this way into a type-1 diabetes mouse model results in the regulation of blood glucose levels. It is believed that this system will be readily adaptable to deliver various biopharmaceutical proteins at remote locations.
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Affiliation(s)
- Bozhidar-Adrian Stefanov
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Maysam Mansouri
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Ghislaine Charpin-El Hamri
- Département Génie Biologique, Institut Universitaire de Technologie, Villeurbanne, Cedex F-69622, France
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
- Faculty of Life Science, University of Basel, Basel, 4058, Switzerland
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5
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Yau B, Hocking S, Andrikopoulos S, Kebede MA. Targeting the insulin granule for modulation of insulin exocytosis. Biochem Pharmacol 2021; 194:114821. [PMID: 34748819 DOI: 10.1016/j.bcp.2021.114821] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 02/08/2023]
Abstract
The pancreatic β-cells control insulin secretion in the body to regulate glucose homeostasis, and β-cell stress and dysfunction is characteristic of Type 2 Diabetes. Pharmacological targeting of the β-cell to increase insulin secretion is typically utilised, however, extended use of common drugs such as sulfonylureas are known to result in secondary failure. Moreover, there is evidence they may induce β-cell failure in the long term. Within β-cells, insulin secretory granules (ISG) serve as compartments to store, process and traffic insulin for exocytosis. There is now growing evidence that ISG exist in multiple populations, distinct in their protein composition, motility, age, and capacity for secretion. In this review, we discuss the implications of a heterogenous ISG population in β-cells and highlight the need for more understanding into how unique ISG populations may be targeted in anti-diabetic therapies.
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Affiliation(s)
- Belinda Yau
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia; Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia.
| | - Samantha Hocking
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia; Central Clinical School, Faculty of Medicine and Health and Department of Endocrinology Royal Prince Alfred Hospital, NSW, Australia
| | | | - Melkam A Kebede
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia; Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
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6
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Amendt T, Jumaa H. Memory IgM protects endogenous insulin from autoimmune destruction. EMBO J 2021; 40:e107621. [PMID: 34369608 PMCID: PMC8408592 DOI: 10.15252/embj.2020107621] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/21/2021] [Accepted: 05/28/2021] [Indexed: 12/19/2022] Open
Abstract
The enormous diversity of antibody specificities is generated by random rearrangement of immunoglobulin gene segments and is important for general protection against pathogens. Since random rearrangement harbors the risk of producing self-destructive antibodies, it is assumed that autoreactive antibody specificities are removed during early B-cell development leading to a peripheral compartment devoid of autoreactivity. Here, we immunized wild-type mice with insulin as a common self-antigen and monitored diabetes symptoms as a measure for autoimmune disease. Our results show that autoreactive anti-insulin IgM and IgG antibodies associated with autoimmune diabetes can readily be generated in wild-type animals. Surprisingly, recall immunizations induced increased titers of high-affinity insulin-specific IgM, which prevented autoimmune diabetes. We refer to this phenomenon as adaptive tolerance, in which high-affinity memory IgM prevents autoimmune destruction by competing with self-destructive antibodies. Together, this study suggests that B-cell tolerance is not defined by the absolute elimination of autoreactive specificities, as harmful autoantibody responses can be generated in wild-type animals. In contrast, inducible generation of autoantigen-specific affinity-matured IgM acts as a protective mechanism preventing self-destruction.
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Affiliation(s)
- Timm Amendt
- Institute of ImmunologyUniversity Hospital UlmUlmGermany
| | - Hassan Jumaa
- Institute of ImmunologyUniversity Hospital UlmUlmGermany
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7
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Kirilmaz OB, Salegaonkar AR, Shiau J, Uzun G, Ko HS, Lee HF, Park S, Kwon G. Study of blood glucose and insulin infusion rate in real-time in diabetic rats using an artificial pancreas system. PLoS One 2021; 16:e0254718. [PMID: 34270619 PMCID: PMC8284668 DOI: 10.1371/journal.pone.0254718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 07/01/2021] [Indexed: 11/19/2022] Open
Abstract
Artificial pancreas system (APS) is an emerging new treatment for type 1 diabetes mellitus. The aim of this study was to develop a rat APS as a research tool and demonstrate its application. We established a rat APS using Medtronic Minimed Pump 722, Medtronic Enlite sensor, and the open artificial pancreas system as a controller. We tested different dilutions of Humalog (100 units/ml) in saline ranged from 1:3 to 1:20 and determined that 1:7 dilution works well for rats with ~500g bodyweight. Blood glucose levels (BGL) of diabetic rats fed with chow diet (58% carbohydrate) whose BGL was managed by the closed-loop APS for the total duration of 207h were in euglycemic range (70-180 mg/dl) for 94.5% of the time with 2.1% and 3.4% for hyperglycemia (>180mg/dl) and hypoglycemia (<70 mg/dl), respectively. Diabetic rats fed with Sucrose pellets (94.8% carbohydrate) for the experimental duration of 175h were in euglycemic range for 61% of the time with 35% and 4% for hyperglycemia and hypoglycemia, respectively. Heathy rats fed with chow diet showed almost a straight line of BGL ~ 95 mg/dl (average 94.8 mg/dl) during the entire experimental period (281h), which was minimally altered by food intake. In the healthy rats, feeding sucrose pellets caused greater range of BGL in high and low levels but still within euglycemic range (99.9%). Next, to study how healthy and diabetic rats handle supra-physiological concentrations of glucose, we intraperitoneally injected various amounts of 50% dextrose (2, 3, 4g/kg) and monitored BGL. Duration of hyperglycemia after injection of 50% dextrose at all three different concentrations was significantly greater for healthy rats than diabetic rats, suggesting that insulin infusion by APS was superior in reducing BGL as compared to natural insulin released from pancreatic β-cells. Ex vivo studies showed that islets isolated from diabetic rats were almost completely devoid of pancreatic β-cells but with intact α-cells as expected. Lipid droplet deposition in the liver of diabetic rats was significantly lower with higher levels of triacylglyceride in the blood as compared to those of healthy rats, suggesting lipid metabolism was altered in diabetic rats. However, glycogen storage in the liver determined by Periodic acid-Schiff staining was not altered in diabetic rats as compared to healthy rats. A rat APS may be used as a powerful tool not only to study alterations of glucose and insulin homeostasis in real-time caused by diet, exercise, hormones, or antidiabetic agents, but also to test mathematical and engineering models of blood glucose prediction or new algorithms for closed-loop APS.
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MESH Headings
- Animals
- Blood Glucose/analysis
- Blood Glucose/drug effects
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/diagnosis
- Diabetes Mellitus, Experimental/therapy
- Diabetes Mellitus, Type 1/blood
- Diabetes Mellitus, Type 1/chemically induced
- Diabetes Mellitus, Type 1/diagnosis
- Diabetes Mellitus, Type 1/therapy
- Glycated Hemoglobin/analysis
- Humans
- Infusions, Intravenous/instrumentation
- Infusions, Intravenous/methods
- Insulin/administration & dosage
- Male
- Pancreas, Artificial
- Rats
- Streptozocin/administration & dosage
- Streptozocin/toxicity
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Affiliation(s)
- Omer Batuhan Kirilmaz
- School of Engineering, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| | | | - Justin Shiau
- School of Pharmacy, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| | - Guney Uzun
- School of Engineering, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| | - Hoo Sang Ko
- School of Engineering, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| | - H. Felix Lee
- School of Engineering, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| | - Sarah Park
- Research and Instructional Services, Duke University, Durham, North Carolina, United States of America
| | - Guim Kwon
- School of Pharmacy, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
- * E-mail:
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8
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Haataja L, Arunagiri A, Hassan A, Regan K, Tsai B, Dhayalan B, Weiss MA, Liu M, Arvan P. Distinct states of proinsulin misfolding in MIDY. Cell Mol Life Sci 2021; 78:6017-6031. [PMID: 34245311 PMCID: PMC8316239 DOI: 10.1007/s00018-021-03871-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/17/2021] [Accepted: 06/01/2021] [Indexed: 12/11/2022]
Abstract
A precondition for efficient proinsulin export from the endoplasmic reticulum (ER) is that proinsulin meets ER quality control folding requirements, including formation of the Cys(B19)–Cys(A20) “interchain” disulfide bond, facilitating formation of the Cys(B7)–Cys(A7) bridge. The third proinsulin disulfide, Cys(A6)–Cys(A11), is not required for anterograde trafficking, i.e., a “lose-A6/A11” mutant [Cys(A6), Cys(A11) both converted to Ser] is well secreted. Nevertheless, an unpaired Cys(A11) can participate in disulfide mispairings, causing ER retention of proinsulin. Among the many missense mutations causing the syndrome of Mutant INS gene-induced Diabetes of Youth (MIDY), all seem to exhibit perturbed proinsulin disulfide bond formation. Here, we have examined a series of seven MIDY mutants [including G(B8)V, Y(B26)C, L(A16)P, H(B5)D, V(B18)A, R(Cpep + 2)C, E(A4)K], six of which are essentially completely blocked in export from the ER in pancreatic β-cells. Three of these mutants, however, must disrupt the Cys(A6)–Cys(A11) pairing to expose a critical unpaired cysteine thiol perturbation of proinsulin folding and ER export, because when introduced into the proinsulin lose-A6/A11 background, these mutants exhibit native-like disulfide bonding and improved trafficking. This maneuver also ameliorates dominant-negative blockade of export of co-expressed wild-type proinsulin. A growing molecular understanding of proinsulin misfolding may permit allele-specific pharmacological targeting for some MIDY mutants.
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Affiliation(s)
- Leena Haataja
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Anoop Arunagiri
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Anis Hassan
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Kaitlin Regan
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University, Indianapolis, IN, 46202, USA
| | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University, Indianapolis, IN, 46202, USA
| | - Ming Liu
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA.,Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, 300052, China
| | - Peter Arvan
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA.
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de Boer P, Giepmans BN. State-of-the-art microscopy to understand islets of Langerhans: what to expect next? Immunol Cell Biol 2021; 99:509-520. [PMID: 33667022 PMCID: PMC8252556 DOI: 10.1111/imcb.12450] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/03/2021] [Accepted: 03/04/2021] [Indexed: 12/12/2022]
Abstract
The discovery of Langerhans and microscopic description of islets in the pancreas were crucial steps in the discovery of insulin. Over the past 150 years, many discoveries in islet biology and type 1 diabetes have been made using powerful microscopic techniques. In the past decade, combination of new probes, animal and tissue models, application of new biosensors and automation of light and electron microscopic methods and other (sub)cellular imaging modalities have proven their potential in understanding the beta cell under (patho)physiological conditions. The imaging evolution, from fluorescent jellyfish to real‐time intravital functional imaging, the revolution in automation and data handling and the increased resolving power of analytical imaging techniques are now converging. Here, we review innovative approaches that address islet biology from new angles by studying cells and molecules at high spatiotemporal resolution and in live models. Broad implementation of these cellular imaging techniques will shed new light on cause/consequence of (mal)function in islets of Langerhans in the years to come.
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Affiliation(s)
- Pascal de Boer
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ben Ng Giepmans
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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10
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Frikke-Schmidt H, Arvan P, Seeley RJ, Cras-Méneur C. Improved in vivo imaging method for individual islets across the mouse pancreas reveals a heterogeneous insulin secretion response to glucose. Sci Rep 2021; 11:603. [PMID: 33436691 PMCID: PMC7804140 DOI: 10.1038/s41598-020-79727-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 12/08/2020] [Indexed: 12/19/2022] Open
Abstract
While numerous techniques can be used to measure and analyze insulin secretion in isolated islets in culture, assessments of insulin secretion in vivo are typically indirect and only semiquantitative. The CpepSfGFP reporter mouse line allows the in vivo imaging of insulin secretion from individual islets after a glucose stimulation, in live, anesthetized mice. Imaging the whole pancreas at high resolution in live mice to track the response of each individual islet over time includes numerous technical challenges and previous reports were only limited in scope and non-quantitative. Elaborating on this previous model-through the development of an improved methodology addressing anesthesia, temperature control and motion blur-we were able to track and quantify longitudinally insulin content throughout a glucose challenge in up to two hundred individual islets simultaneously. Through this approach we demonstrate quantitatively for the first time that while isolated islets respond homogeneously to glucose in culture, their profiles differ significantly in vivo. Independent of size or location, some islets respond sharply to a glucose stimulation while others barely secrete at all. This platform therefore provides a powerful approach to study the impact of disease, diet, surgery or pharmacological treatments on insulin secretion in the intact pancreas in vivo.
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Affiliation(s)
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, 2800 Plymouth Rd, Ann Arbor, MI, 48109, USA
| | - Randy J Seeley
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, 2800 Plymouth Rd, Ann Arbor, MI, 48109, USA
| | - Corentin Cras-Méneur
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, 2800 Plymouth Rd, Ann Arbor, MI, 48109, USA.
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11
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Clavijo Jordan V, Hines CDG, Gantert LT, Wang S, Conarello S, Preihs C, Chirayil S, Klimas M, Evelhoch JL, Sherry AD. Imaging Beta-Cell Function in the Pancreas of Non-Human Primates Using a Zinc-Sensitive MRI Contrast Agent. Front Endocrinol (Lausanne) 2021; 12:641722. [PMID: 34122330 PMCID: PMC8187943 DOI: 10.3389/fendo.2021.641722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/26/2021] [Indexed: 12/03/2022] Open
Abstract
Non-invasive beta cell function measurements may provide valuable information for improving diabetes diagnostics and disease management as the integrity and function of pancreatic beta cells have been found to be compromised in Type-1 and Type-2 diabetes. Currently, available diabetes assays either lack functional information or spatial identification of beta cells. In this work, we introduce a method to assess the function of beta cells in the non-human primate pancreas non-invasively with MRI using a Gd-based zinc(II) sensor as a contrast agent, Gd-CP027. Additionally, we highlight the role of zinc(II) ions in the paracrine signaling of the endocrine pancreas via serological measurements of insulin and c-peptide. Non-human primates underwent MRI exams with simultaneous blood sampling during a Graded Glucose Infusion (GGI) with Gd-CP027 or with a non-zinc(II) sensitive contrast agent, gadofosveset. Contrast enhancement of the pancreas resulting from co-release of zinc(II) ion with insulin was observed focally when using the zinc(II)-specific agent, Gd-CP027, whereas little enhancement was detected when using gadofosveset. The contrast enhancement detected by Gd-CP027 increased in parallel with an increased dose of infused glucose. Serological measurements of C-peptide and insulin indicate that Gd-CP027, a high affinity zinc(II) contrast agent, potentiates their secretion only as a function of glucose stimulation. Taken in concert, this assay offers the possibility of detecting beta cell function in vivo non-invasively with MRI and underscores the role of zinc(II) in endocrine glucose metabolism.
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Affiliation(s)
- Veronica Clavijo Jordan
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | | | - Liza T. Gantert
- Translational Biomarkers, Merck & Co., Inc., Kenilworth, NJ, United States
| | - Shubing Wang
- Biometrics Research, Merck & Co., Inc., Kenilworth, NJ, United States
| | | | - Christian Preihs
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
- VitalQuan, LLC, Dallas, TX, United States
| | - Sara Chirayil
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Michael Klimas
- Translational Biomarkers, Merck & Co., Inc., Kenilworth, NJ, United States
| | | | - A. Dean Sherry
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
- VitalQuan, LLC, Dallas, TX, United States
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
- Department of Chemistry & Biochemistry, The University of Texas at Dallas, Richardson, TX, United States
- *Correspondence: A. Dean Sherry,
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12
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Thapa B, Suh EH, Parrott D, Khalighinejad P, Sharma G, Chirayil S, Sherry AD. Imaging β-Cell Function Using a Zinc-Responsive MRI Contrast Agent May Identify First Responder Islets. Front Endocrinol (Lausanne) 2021; 12:809867. [PMID: 35173681 PMCID: PMC8842654 DOI: 10.3389/fendo.2021.809867] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/16/2021] [Indexed: 01/05/2023] Open
Abstract
An imaging method for detecting β-cell function in real-time in the rodent pancreas could provide new insights into the biological mechanisms involving loss of β-cell function during development of type 2 diabetes and for testing of new drugs designed to modulate insulin secretion. In this study, we used a zinc-responsive MRI contrast agent and an optimized 2D MRI method to show that glucose stimulated insulin and zinc secretion can be detected as functionally active "hot spots" in the tail of the rat pancreas. A comparison of functional images with histological markers show that insulin and zinc secretion does not occur uniformly among all pancreatic islets but rather that some islets respond rapidly to an increase in glucose while others remain silent. Zinc and insulin secretion was shown to be altered in streptozotocin and exenatide treated rats thereby verifying that this simple MRI technique is responsive to changes in β-cell function.
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Affiliation(s)
- Bibek Thapa
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Eul Hyun Suh
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Daniel Parrott
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Pooyan Khalighinejad
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Gaurav Sharma
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Sara Chirayil
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - A. Dean Sherry
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, United States
- *Correspondence: A. Dean Sherry, ;
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13
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Khalighinejad P, Parrott D, Sherry AD. Imaging Tissue Physiology In Vivo by Use of Metal Ion-Responsive MRI Contrast Agents. Pharmaceuticals (Basel) 2020; 13:E268. [PMID: 32987721 PMCID: PMC7598704 DOI: 10.3390/ph13100268] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 12/18/2022] Open
Abstract
Paramagnetic metal ion complexes, mostly based on gadolinium (Gd3+), have been used for over 30 years as magnetic resonance imaging (MRI) contrast agents. Gd3+-based contrast agents have a strong influence on T1 relaxation times and are consequently the most commonly used agents in both the clinical and research environments. Zinc is an essential element involved with over 3000 different cellular proteins, and disturbances in tissue levels of zinc have been linked to a wide range of pathologies, including Alzheimer's disease, prostate cancer, and diabetes mellitus. MR contrast agents that respond to the presence of Zn2+ in vivo offer the possibility of imaging changes in Zn2+ levels in real-time with the superior spatial resolution offered by MRI. Such responsive agents, often referred to as smart agents, are typically composed of a paramagnetic metal ion with a ligand encapsulating it and one or more chelating units that selectively bind with the analyte of interest. Translation of these agents into clinical radiology is the next goal. In this review, we discuss Gd3+-based MR contrast agents that respond to a change in local Zn2+ concentration.
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Affiliation(s)
- Pooyan Khalighinejad
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA;
| | - Daniel Parrott
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA;
| | - A. Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA;
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA;
- Department of Chemistry & Biochemistry, University of Texas at Dallas, Richardson, TX 75080, USA
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14
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Milordini G, Zacco E, Percival M, Puglisi R, Dal Piaz F, Temussi P, Pastore A. The Role of Glycation on the Aggregation Properties of IAPP. Front Mol Biosci 2020; 7:104. [PMID: 32582762 PMCID: PMC7284065 DOI: 10.3389/fmolb.2020.00104] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 05/05/2020] [Indexed: 12/19/2022] Open
Abstract
Epidemiological evidence shows an increased risk for developing Alzheimer's disease in people affected by diabetes, a pathology associated with increased hyperglycemia. A potential factor that could explain this link could be the role that sugars may play in both diseases under the form of glycation. Contrary to glycosylation, glycation is an enzyme-free reaction that leads to formation of toxic advanced glycation end-products (AGEs). In diabetes, the islet amyloid polypeptide (IAPP or amylin) is found to be heavily glycated and to form toxic amyloid-like aggregates, similar to those observed for the Aβ peptides, often also heavily glycated, observed in Alzheimer patients. Here, we studied the effects of glycation on the structure and aggregation properties of IAPP with several biophysical techniques ranging from fluorescence to circular dichroism, mass spectrometry and atomic force microscopy. We demonstrate that glycation occurs exclusively on the N-terminal lysine leaving the only arginine (Arg11) unmodified. At variance with recent studies, we show that the dynamical interplay between glycation and aggregation affects the structure of the peptide, slows down the aggregation process and influences the aggregate morphology.
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Affiliation(s)
- Giulia Milordini
- UK Dementia Research Institute at the Maurice Wohl Institute of King's College London, London, United Kingdom
| | - Elsa Zacco
- UK Dementia Research Institute at the Maurice Wohl Institute of King's College London, London, United Kingdom
| | - Matthew Percival
- UK Dementia Research Institute at the Maurice Wohl Institute of King's College London, London, United Kingdom
| | - Rita Puglisi
- UK Dementia Research Institute at the Maurice Wohl Institute of King's College London, London, United Kingdom
| | - Fabrizio Dal Piaz
- Dipartimento di Medicina, Chirurgia e Odontoiatria "Scuola Medica Salernitana", University of Salerno, Salerno, Italy
| | - Pierandrea Temussi
- UK Dementia Research Institute at the Maurice Wohl Institute of King's College London, London, United Kingdom
| | - Annalisa Pastore
- UK Dementia Research Institute at the Maurice Wohl Institute of King's College London, London, United Kingdom
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15
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Shariati K, Pappalardo Z, Chopra DG, Yiv N, Sheen R, Ku G. Selective monitoring of insulin secretion after CRISPR interference in intact pancreatic islets despite submaximal infection. Islets 2020; 12:59-69. [PMID: 32579048 PMCID: PMC7527018 DOI: 10.1080/19382014.2020.1752072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Virus-mediated gene knockdown in intact pancreatic islets is technically challenging due to poor infection of the center of the islet. Because the cells that do not have knockdown have normal insulin secretion, measuring changes in insulin secretion after gene knockdown is challenging. We describe a method to monitor insulin secretion from only the beta cells with knockdown of a gene of interest in intact islets using a single lentivirus containing a guide RNA, a luciferase insulin secretion reporter and a dCas9-KRAB cassette. This method allows rapid and inexpensive monitoring of insulin secretion from only those beta cells with knockdown, circumventing the problem of incomplete islet infection.
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Affiliation(s)
| | | | | | | | - Robin Sheen
- Diabetes Center, UCSF, San Francisco, CA, USA
| | - Gregory Ku
- Diabetes Center, UCSF, San Francisco, CA, USA
- Division of Endocrinology and Metabolism, Department of Medicine, UCSF, San Francisco, CA, USA
- CONTACT Gregory Ku 513 Parnassus Ave., San Francisco, CA94143
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16
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Li WH. Functional analysis of islet cells in vitro, in situ, and in vivo. Semin Cell Dev Biol 2020; 103:14-19. [PMID: 32081627 DOI: 10.1016/j.semcdb.2020.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/05/2020] [Indexed: 12/20/2022]
Abstract
The islet of Langerhans contains at least five types of endocrine cells producing distinct hormones. In response to nutrient or neuronal stimulation, islet endocrine cells release biochemicals including peptide hormones to regulate metabolism and to control glucose homeostasis. It is now recognized that malfunction of islet cells, notably insufficient insulin release of β-cells and hypersecretion of glucagon from α-cells, represents a causal event leading to hyperglycemia and frank diabetes, a disease that is increasing at an alarming rate to reach an epidemic level worldwide. Understanding the mechanisms regulating stimulus-secretion coupling and investigating how islet β-cells maintain a robust secretory activity are important topics in islet biology and diabetes research. To facilitate such studies, a number of biological systems and assay platforms have been developed for the functional analysis of islet cells. These technologies have enabled detailed analyses of individual islets at the cellular level, either in vitro, in situ, or in vivo.
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Affiliation(s)
- Wen-Hong Li
- Departments of Cell Biology and of Biochemistry, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, 75390-9039, United States.
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17
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Taddeo EP, Alsabeeh N, Baghdasarian S, Wikstrom JD, Ritou E, Sereda S, Erion K, Li J, Stiles L, Abdulla M, Swanson Z, Wilhelm JJ, Bellin MD, Kibbey RG, Liesa M, Shirihai OS. Mitochondrial Proton Leak Regulated by Cyclophilin D Elevates Insulin Secretion in Islets at Nonstimulatory Glucose Levels. Diabetes 2020; 69:131-145. [PMID: 31740442 PMCID: PMC6971491 DOI: 10.2337/db19-0379] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 11/11/2019] [Indexed: 12/13/2022]
Abstract
Fasting hyperinsulinemia precedes the development of type 2 diabetes. However, it is unclear whether fasting insulin hypersecretion is a primary driver of insulin resistance or a consequence of the progressive increase in fasting glycemia induced by insulin resistance in the prediabetic state. Herein, we have discovered a mechanism that specifically regulates non-glucose-stimulated insulin secretion (NGSIS) in pancreatic islets that is activated by nonesterified free fatty acids, the major fuel used by β-cells during fasting. We show that the mitochondrial permeability transition pore regulator cyclophilin D (CypD) promotes NGSIS, but not glucose-stimulated insulin secretion, by increasing mitochondrial proton leak. Islets from prediabetic obese mice show significantly higher CypD-dependent proton leak and NGSIS compared with lean mice. Proton leak-mediated NGSIS is conserved in human islets and is stimulated by exposure to nonesterified free fatty acids at concentrations observed in obese subjects. Mechanistically, proton leak activates islet NGSIS independently of mitochondrial ATP synthesis but ultimately requires closure of the KATP channel. In summary, we have described a novel nonesterified free fatty acid-stimulated pathway that selectively drives pancreatic islet NGSIS, which may be therapeutically exploited as an alternative way to halt fasting hyperinsulinemia and the progression of type 2 diabetes.
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Affiliation(s)
- Evan P Taddeo
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Nour Alsabeeh
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Siyouneh Baghdasarian
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Jakob D Wikstrom
- Dermatology and Venereology Unit, Department of Medicine, Karolinska Institutet, and Department of Dermato-Venereology, Karolinska University Hospital, Stockholm, Sweden
| | - Eleni Ritou
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Samuel Sereda
- Endocrinology, Diabetes, Nutrition and Weight Management Section, Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Karel Erion
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Jin Li
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Linsey Stiles
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Muhamad Abdulla
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN
| | - Zachary Swanson
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN
| | - Joshua J Wilhelm
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN
| | - Melena D Bellin
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN
| | - Richard G Kibbey
- Departments of Internal Medicine (Endocrinology) and Cellular & Molecular Physiology, Yale University, New Haven, CT
| | - Marc Liesa
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA
| | - Orian S Shirihai
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
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18
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He J, Zhu NL, Kong J, Peng P, Li LF, Wei XL, Jiang YY, Zhang YL, Bian BL, She GM, Shi RB. A Newly Discovered Phenylethanoid Glycoside from Stevia rebaudiana Bertoni Affects Insulin Secretion in Rat INS-1 Islet β Cells. Molecules 2019; 24:molecules24224178. [PMID: 31752141 PMCID: PMC6891645 DOI: 10.3390/molecules24224178] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 11/08/2019] [Accepted: 11/10/2019] [Indexed: 11/17/2022] Open
Abstract
The tea-like beverage Stevia rebaudiana Bertoni (Stevia) is popular in China because it reduces blood glucose and has a sweet taste. In this work, a comprehensive quality assessment of Stevia led to the discovery of five phenylethanoid glycosides, namely steviophethanoside (1), cuchiloside (2), salidroside (3), icariside D (4), and tyrosol (5). Of them, compound 1 is a novel compound. Mass spectrometry and NMR spectroscopy were employed to confirm the absolute configuration. A hydrolytic step with 4 N TFA at 95 °C for 4 h was used to confirm the monosaccharides. In addition, Discovery Studio 4.0 was used to predict the ADME and toxicity activity of compound 1. The results suggested that compound 1 was biocompatible and had poor toxicity, which was verified by rat INS-1 islet β cells through an MTT assay. Meanwhile, a significant stimulatory effect on INS-1 cells was observed, which indicated a hypoglycemic effect of compound 1. This is the first report that describes a natural, novel, and hypoglycemic phenylethanoid glycoside in Stevia.
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Affiliation(s)
- Jing He
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, The Key Unit of Exploring Effective Substances of Classical and Famous Prescription of SATCM, Beijing 102488, China; (J.H.); (N.-L.Z.); (J.K.); (P.P.); (L.-F.L.); (Y.-Y.J.); (Y.-L.Z.)
| | - Nai-Liang Zhu
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, The Key Unit of Exploring Effective Substances of Classical and Famous Prescription of SATCM, Beijing 102488, China; (J.H.); (N.-L.Z.); (J.K.); (P.P.); (L.-F.L.); (Y.-Y.J.); (Y.-L.Z.)
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Beijing 200293, China
| | - Jing Kong
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, The Key Unit of Exploring Effective Substances of Classical and Famous Prescription of SATCM, Beijing 102488, China; (J.H.); (N.-L.Z.); (J.K.); (P.P.); (L.-F.L.); (Y.-Y.J.); (Y.-L.Z.)
| | - Ping Peng
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, The Key Unit of Exploring Effective Substances of Classical and Famous Prescription of SATCM, Beijing 102488, China; (J.H.); (N.-L.Z.); (J.K.); (P.P.); (L.-F.L.); (Y.-Y.J.); (Y.-L.Z.)
| | - Lin-Fu Li
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, The Key Unit of Exploring Effective Substances of Classical and Famous Prescription of SATCM, Beijing 102488, China; (J.H.); (N.-L.Z.); (J.K.); (P.P.); (L.-F.L.); (Y.-Y.J.); (Y.-L.Z.)
| | - Xiao-Lu Wei
- Quality Standards, Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China; (X.-L.W.); (B.-L.B.)
| | - Yan-Yan Jiang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, The Key Unit of Exploring Effective Substances of Classical and Famous Prescription of SATCM, Beijing 102488, China; (J.H.); (N.-L.Z.); (J.K.); (P.P.); (L.-F.L.); (Y.-Y.J.); (Y.-L.Z.)
| | - Yan-Ling Zhang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, The Key Unit of Exploring Effective Substances of Classical and Famous Prescription of SATCM, Beijing 102488, China; (J.H.); (N.-L.Z.); (J.K.); (P.P.); (L.-F.L.); (Y.-Y.J.); (Y.-L.Z.)
| | - Bao-Lin Bian
- Quality Standards, Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China; (X.-L.W.); (B.-L.B.)
| | - Gai-Mei She
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, The Key Unit of Exploring Effective Substances of Classical and Famous Prescription of SATCM, Beijing 102488, China; (J.H.); (N.-L.Z.); (J.K.); (P.P.); (L.-F.L.); (Y.-Y.J.); (Y.-L.Z.)
- Correspondence: (G.-M.S.); (R.-B.S.); Tel.: +86-10-5391-2129 (R.-B.S.)
| | - Ren-Bing Shi
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, The Key Unit of Exploring Effective Substances of Classical and Famous Prescription of SATCM, Beijing 102488, China; (J.H.); (N.-L.Z.); (J.K.); (P.P.); (L.-F.L.); (Y.-Y.J.); (Y.-L.Z.)
- Correspondence: (G.-M.S.); (R.-B.S.); Tel.: +86-10-5391-2129 (R.-B.S.)
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19
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The effect of C-peptide on diabetic nephropathy: A review of molecular mechanisms. Life Sci 2019; 237:116950. [PMID: 31605709 DOI: 10.1016/j.lfs.2019.116950] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 02/07/2023]
Abstract
C-peptide is a small peptide connecting two chains of proinsulin molecule and is dissociated before the release of insulin. It is secreted in an equimolar amount to insulin from the pancreatic beta-cells into the circulation. Recent evidence demonstrates that it has other physiologic activities beyond its structural function. C-peptide modulates intracellular signaling pathways in various pathophysiologic states and, could potentially be a new therapeutic target for different disorders including diabetic complications. There is growing evidence that c-peptide has modulatory effects on the molecular mechanisms involved in the development of diabetic nephropathy. Although we have little direct evidence, pharmacological properties of c-peptide suggest that it can provide potent renoprotective effects especially, in a c-peptide deficient milieu as in type 1 diabetes mellitus. In this review, we describe possible molecular mechanisms by which c-peptide may improve renal efficiency in a diabetic milieu.
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20
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Godin E, Nguyen PT, Zottig X, Bourgault S. Identification of a hinge residue controlling islet amyloid polypeptide self-assembly and cytotoxicity. J Biol Chem 2019; 294:8452-8463. [PMID: 30975901 DOI: 10.1074/jbc.ra118.006454] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 04/04/2019] [Indexed: 11/06/2022] Open
Abstract
The islet amyloid polypeptide (IAPP) is a 37-residue peptide hormone whose deposition as amyloid fibrils in the pancreatic islets is associated with type 2 diabetes. Previous studies have suggested that residue Asn-21 plays a critical role in the in vitro self-assembly of IAPP. Herein, we studied structure-self-assembly relationships focusing on position 21 to gain detailed insights into the molecular mechanisms of IAPP self-assembly and to probe the conformational nature of the toxic assemblies associated with β-cell death. Thioflavin T (ThT) fluorescence, CD spectroscopy, and transmission EM analysis revealed that the Asn-21 amide side chain is not required for IAPP nucleation and amyloid elongation, as N21A and N21G variants assembled into prototypical fibrils. In contrast, Asn-21 substitution with the conformationally constrained and turn-inducing residue Pro accelerated IAPP self-assembly. Successive substitutions with hydrophobic residues led to the formation of ThT-negative β-sheet-rich aggregates having high surface hydrophobicity. Cell-based assays revealed no direct correlation between the in vitro amyloidogenicity of these variants and their toxicity. In contrast, leakage of anionic lipid vesicles disclosed that membrane disruption is closely associated with cytotoxicity. We observed that the N21F variant self-assembles into worm-like aggregates, causing loss of lipid membrane structural integrity and inducing β-cell apoptosis. These results indicate that specific intra- and intermolecular interactions involving Asn-21 promote IAPP primary nucleation events by modulating the conformational conversion of the oligomeric intermediates into amyloid fibrils. Our study identifies position 21 as a hinge residue that modulates IAPP amyloidogenicity and cytotoxicity.
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Affiliation(s)
- Elizabeth Godin
- Department of Chemistry, Pharmaqam, Université du Québec à Montréal, Montreal, Quebec H3C 3P8, Canada; Quebec Network for Research on Protein Function, Engineering, and Applications, PROTEO, Quebec G1V 0A6, Canada
| | - Phuong Trang Nguyen
- Department of Chemistry, Pharmaqam, Université du Québec à Montréal, Montreal, Quebec H3C 3P8, Canada; Quebec Network for Research on Protein Function, Engineering, and Applications, PROTEO, Quebec G1V 0A6, Canada
| | - Ximena Zottig
- Department of Chemistry, Pharmaqam, Université du Québec à Montréal, Montreal, Quebec H3C 3P8, Canada; Quebec Network for Research on Protein Function, Engineering, and Applications, PROTEO, Quebec G1V 0A6, Canada
| | - Steve Bourgault
- Department of Chemistry, Pharmaqam, Université du Québec à Montréal, Montreal, Quebec H3C 3P8, Canada; Quebec Network for Research on Protein Function, Engineering, and Applications, PROTEO, Quebec G1V 0A6, Canada.
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21
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Wang Z, Gao L, Guo X, Feng C, Deng K, Lian W, Feng M, Bao X, Xing B. Preoperative Fasting C-Peptide Acts as a Promising Predictor of Improved Glucose Tolerance in Patients With Acromegaly After Transsphenoidal Surgery: A Retrospective Study of 64 Cases From a Large Pituitary Center in China. Front Endocrinol (Lausanne) 2019; 10:736. [PMID: 31736874 PMCID: PMC6838023 DOI: 10.3389/fendo.2019.00736] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 10/10/2019] [Indexed: 12/19/2022] Open
Abstract
Purpose: Abnormal glucose metabolism is one of the most frequent acromegaly complications. Improvement of glucose metabolism can be observed only in half of acromegaly patients after surgery. We aimed to investigate the risk factors for determining abnormal glucose metabolism before surgery in patients with acromegaly, and to explore the predictors of improved preoperative glucose intolerance after surgery. Methods: We retrospectively reviewed 64 patients who received transsphenoidal surgery for acromegaly. Growth hormone (GH), insulin-like growth factor-1 (IGF-1) and glucose metabolism were assessed before, immediately after, and 3 months after surgery. Glucose metabolic parameters included glycosylated hemoglobin (HbA1c), plasma glucose (PG), C-peptide (CP), insulin (INS), and the indices of β-cell function, insulin sensitivity, and insulin resistance (IR). Results: Preoperatively, 18 patients (28.1%) had diabetes (DM), 34 (53.1%) had prediabetes (PreDM), and 12 (18.8%) had normal glucose tolerance (NGT). All the indices of pancreatic β-cell function were significantly lower in patients with DM than those with PreDM and NGT (all P < 0.005). IGF-1 was significantly positively correlated with insulin sensitivity and IR (P < 0.05), while GH was not. Postoperatively, glucose tolerance was improved in 71.2% of patients (37/52) with preoperative glucose intolerance. Insulin sensitivity was increased, while β-cell function and IR were decreased in most patients after surgery, regardless of whether their acromegaly achieved remission. A multivariate logistic regression analysis revealed that preoperative fasting C-peptide (FCP, OR = 2.639, P = 0.022), disposition index (DI, OR = 1.397, P = 0.043) and Predictor-2 (OR = 0.578, P = 0.035) were determined to be the predictors for improved glucose tolerance status after surgery. Afterwards, through Receiver operating characteristic (ROC) analyses, FCP >2.445 ng/ml was the best independent predictor, with an 86.6% PPV (positive predictive value) and a 74.5% NPV (negative predictive value). Conclusions: Preoperative high FCP is a promising postsurgical predictor of improved glucose tolerance in patients with acromegaly. Oral glucose tolerance testing (OGTT) and HbA1c should be monitored regularly after surgery, and diabetes management should be adjusted based on the patient's latest glucose tolerance status.
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Affiliation(s)
- Zihao Wang
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Chinese Pituitary Adenoma Cooperative Group, China Pituitary Disease Registry Center, Beijing, China
| | - Lu Gao
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Chinese Pituitary Adenoma Cooperative Group, China Pituitary Disease Registry Center, Beijing, China
| | - Xiaopeng Guo
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Chinese Pituitary Adenoma Cooperative Group, China Pituitary Disease Registry Center, Beijing, China
| | - Chenzhe Feng
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Chinese Pituitary Adenoma Cooperative Group, China Pituitary Disease Registry Center, Beijing, China
| | - Kan Deng
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Chinese Pituitary Adenoma Cooperative Group, China Pituitary Disease Registry Center, Beijing, China
| | - Wei Lian
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Chinese Pituitary Adenoma Cooperative Group, China Pituitary Disease Registry Center, Beijing, China
| | - Ming Feng
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Chinese Pituitary Adenoma Cooperative Group, China Pituitary Disease Registry Center, Beijing, China
| | - Xinjie Bao
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Chinese Pituitary Adenoma Cooperative Group, China Pituitary Disease Registry Center, Beijing, China
| | - Bing Xing
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Chinese Pituitary Adenoma Cooperative Group, China Pituitary Disease Registry Center, Beijing, China
- *Correspondence: Bing Xing
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22
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Martins AF, Clavijo Jordan V, Bochner F, Chirayil S, Paranawithana N, Zhang S, Lo ST, Wen X, Zhao P, Neeman M, Sherry AD. Imaging Insulin Secretion from Mouse Pancreas by MRI Is Improved by Use of a Zinc-Responsive MRI Sensor with Lower Affinity for Zn 2+ Ions. J Am Chem Soc 2018; 140:17456-17464. [PMID: 30484648 DOI: 10.1021/jacs.8b07607] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
It has been demonstrated that divalent zinc ions packaged with insulin in β-cell granules can be detected by MRI during glucose-stimulated insulin secretion using a gadolinium-based Zn2+-sensitive agent. This study was designed to evaluate whether a simpler agent design having single Zn2+-sensing moieties but with variable Zn2+ binding affinities might also detect insulin secretion from the pancreas. Using an implanted MR-compatible window designed to hold the pancreas in a fixed position for imaging, we now demonstrate that focally intense "hot spots" can be detected in the tail of the pancreas using these agents after administration of glucose to stimulate insulin secretion. Histological staining of the same tissue verified that the hot spots identified by imaging correspond to clusters of islets, perhaps reflecting first-responder islets that are most responsive to a sudden increase in glucose. A comparison of images obtained when using a high-affinity Zn2+ sensor versus a lower-affinity sensor showed that the lower-affinity sensors produced the best image contrast. An equilibrium model that considers all possible complexes formed between Zn2+, the GdL sensor, and HSA predicts that a GdL sensor with lower affinity for Zn2+ generates a lower background signal from endogenous Zn2+ prior to glucose-stimulated insulin secretion (GSIS) and that the weaker binding affinity agent is more responsive to a further increase in Zn2+ concentration near β-cells after GSIS. These model predictions are consistent with the in vivo imaging observations.
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Affiliation(s)
- André F Martins
- Department of Chemistry and Biochemistry , University of Texas at Dallas , Richardson , Texas 75080 , United States.,Advanced Imaging Research Center , University of Texas Southwestern Medical Center , Dallas , Texas 75390-8568 , United States
| | - Veronica Clavijo Jordan
- Advanced Imaging Research Center , University of Texas Southwestern Medical Center , Dallas , Texas 75390-8568 , United States
| | - Filip Bochner
- Department of Biological Regulation , The Weizmann Institute of Science , 7610001 Rehovot , Israel
| | - Sara Chirayil
- Advanced Imaging Research Center , University of Texas Southwestern Medical Center , Dallas , Texas 75390-8568 , United States
| | - Namini Paranawithana
- Department of Chemistry and Biochemistry , University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Shanrong Zhang
- Advanced Imaging Research Center , University of Texas Southwestern Medical Center , Dallas , Texas 75390-8568 , United States
| | - Su-Tang Lo
- Advanced Imaging Research Center , University of Texas Southwestern Medical Center , Dallas , Texas 75390-8568 , United States
| | - Xiaodong Wen
- Advanced Imaging Research Center , University of Texas Southwestern Medical Center , Dallas , Texas 75390-8568 , United States
| | - Piyu Zhao
- Department of Chemistry and Biochemistry , University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Michal Neeman
- Department of Biological Regulation , The Weizmann Institute of Science , 7610001 Rehovot , Israel
| | - A Dean Sherry
- Department of Chemistry and Biochemistry , University of Texas at Dallas , Richardson , Texas 75080 , United States.,Advanced Imaging Research Center , University of Texas Southwestern Medical Center , Dallas , Texas 75390-8568 , United States
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23
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de Faudeur G, Brouwers B, Schuit F, Creemers JWM, Ramos-Molina B. Transgenic Artifacts Caused by Passenger Human Growth Hormone. Trends Endocrinol Metab 2018; 29:670-674. [PMID: 29921469 DOI: 10.1016/j.tem.2018.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 05/18/2018] [Accepted: 05/29/2018] [Indexed: 12/26/2022]
Abstract
The minigene encoding human growth hormone (hGH) has been incorporated into over 300 transgenic mouse lines to improve transgene expression. However, unexpected and functional hGH expression can drastically alter physiology. We list here the mouse lines in which ectopic hGH has been confirmed, and we provide a wiki for lines awaiting analysis.
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Affiliation(s)
- Geoffroy de Faudeur
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium; These authors contributed equally
| | - Bas Brouwers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium; Metabolic Research Laboratories, Wellcome Trust Medical Research Council (MRC) Institute of Metabolic Science, University of Cambridge, Cambridge, UK; These authors contributed equally
| | - Frans Schuit
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - John W M Creemers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium.
| | - Bruno Ramos-Molina
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium; Institute of Biomedical Research in Malaga (IBIMA), Virgen de la Victoria University Hospital, Malaga, Spain; Centro de Investigación Biomédica en Red (CIBER) Physiopathology of Obesity and Nutrition (CIBEROBN), Institute of Health Carlos III, Madrid, Spain
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24
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Taddeo EP, Stiles L, Sereda S, Ritou E, Wolf DM, Abdullah M, Swanson Z, Wilhelm J, Bellin M, McDonald P, Caradonna K, Neilson A, Liesa M, Shirihai OS. Individual islet respirometry reveals functional diversity within the islet population of mice and human donors. Mol Metab 2018; 16:150-159. [PMID: 30098928 PMCID: PMC6157638 DOI: 10.1016/j.molmet.2018.07.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/25/2018] [Accepted: 07/01/2018] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE Islets from the same pancreas show remarkable variability in glucose sensitivity. While mitochondrial respiration is essential for glucose-stimulated insulin secretion, little is known regarding heterogeneity in mitochondrial function at the individual islet level. This is due in part to a lack of high-throughput and non-invasive methods for detecting single islet function. METHODS We have developed a novel non-invasive, high-throughput methodology capable of assessing mitochondrial respiration in large-sized individual islets using the XF96 analyzer (Agilent Technologies). RESULTS By increasing measurement sensitivity, we have reduced the minimal size of mouse and human islets needed to assess mitochondrial respiration to single large islets of >35,000 μm2 area (∼210 μm diameter). In addition, we have measured heterogeneous glucose-stimulated mitochondrial respiration among individual human and mouse islets from the same pancreas, allowing population analyses of islet mitochondrial function for the first time. CONCLUSIONS We have developed a novel methodology capable of analyzing mitochondrial function in large-sized individual islets. By highlighting islet functional heterogeneity, we hope this methodology can significantly advance islet research.
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Affiliation(s)
- Evan P Taddeo
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA
| | - Linsey Stiles
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA
| | - Samuel Sereda
- Department of Medicine, Endocrinology, Diabetes, Nutrition and Weight Management Section, Boston University School of Medicine, 650 Albany St., Room 840, Boston, MA 02118, USA
| | - Eleni Ritou
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA
| | - Dane M Wolf
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA
| | - Muhamad Abdullah
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA
| | - Zachary Swanson
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA
| | - Josh Wilhelm
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA
| | - Melena Bellin
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA
| | - Patrick McDonald
- Center for Health Research Innovation, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | | | | | - Marc Liesa
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA.
| | - Orian S Shirihai
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA; Department of Medicine, Endocrinology, Diabetes, Nutrition and Weight Management Section, Boston University School of Medicine, 650 Albany St., Room 840, Boston, MA 02118, USA.
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25
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Blodgett DM, Redick SD, Harlan DM. Surprising Heterogeneity of Pancreatic Islet Cell Subsets. Cell Syst 2018; 3:330-332. [PMID: 27788358 DOI: 10.1016/j.cels.2016.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two studies clearly demonstrate that pancreatic islets and, more specifically, their cellular constituents, display a much greater complexity than previously appreciated.
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Affiliation(s)
- David M Blodgett
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655; Math and Science Division, Babson College, Wellesley, MA 01457, USA
| | - Sambra D Redick
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655
| | - David M Harlan
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655.
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26
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Nasteska D, Hodson DJ. The role of beta cell heterogeneity in islet function and insulin release. J Mol Endocrinol 2018; 61:R43-R60. [PMID: 29661799 PMCID: PMC5976077 DOI: 10.1530/jme-18-0011] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 04/16/2018] [Indexed: 12/15/2022]
Abstract
It is becoming increasingly apparent that not all insulin-secreting beta cells are equal. Subtle differences exist at the transcriptomic and protein expression levels, with repercussions for beta cell survival/proliferation, calcium signalling and insulin release. Notably, beta cell heterogeneity displays plasticity during development, metabolic stress and type 2 diabetes mellitus (T2DM). Thus, heterogeneity or lack thereof may be an important contributor to beta cell failure during T2DM in both rodents and humans. The present review will discuss the molecular and cellular features of beta cell heterogeneity at both the single-cell and islet level, explore how this influences islet function and insulin release and look into the alterations that may occur during obesity and T2DM.
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Affiliation(s)
- Daniela Nasteska
- Institute of Metabolism and Systems Research (IMSR)University of Birmingham, Edgbaston, UK
- Centre for EndocrinologyDiabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
- COMPARE University of Birmingham and University of Nottingham MidlandsBirmingham, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR)University of Birmingham, Edgbaston, UK
- Centre for EndocrinologyDiabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
- COMPARE University of Birmingham and University of Nottingham MidlandsBirmingham, UK
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27
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Guruswamy Damodaran R, Poussard A, Côté B, Andersen PL, Vermette P. Insulin secretion kinetics from single islets reveals distinct subpopulations. Biotechnol Prog 2018; 34:1059-1068. [PMID: 29603910 DOI: 10.1002/btpr.2632] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/14/2018] [Indexed: 12/12/2022]
Abstract
Type II diabetes progresses with inadequate insulin secretion and prolonged elevated circulating glucose levels. Also, pancreatic islets isolated for transplantation or tissue engineering can be exposed to glucose over extended timeframe. We hypothesized that isolated pancreatic islets can secrete insulin over a prolonged period of time when incubated in glucose solution and that not all islets release insulin in unison. Insulin secretion kinetics was examined and modeled from single mouse islets in response to chronic glucose exposure (2.8-20 mM). Results with single islets were compared to those from pools of islets. Kinetic analysis of 58 single islets over 72 h in response to elevated glucose revealed distinct insulin secretion profiles: slow-, fast-, and constant-rate secretors, with slow-secretors being most prominent (ca., 50%). Variations in the temporal response to glucose therefore exist. During short-term (<4 h) exposure to elevated glucose few islets are responding with sustained insulin release. The model allowed studying the influence of islet size, revealing no clear effect. At high-glucose concentrations, when secretion is normalized to islet volume, the tendency is that smaller islets secrete more insulin. At high-glucose concentrations, insulin secretion from single islets is representative of islet populations, while under low-glucose conditions pooled islets did not behave as single ones. The characterization of insulin secretion over prolonged periods complements studies on insulin secretion performed over short timeframe. Further investigation of these differences in secretion profiles may resolve open-ended questions on pre-diabetic conditions and transplanted islets performance. This study deliberates the importance of size of islets in insulin secretion. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1059-1068, 2018.
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Affiliation(s)
- Rajesh Guruswamy Damodaran
- Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke, Dept. of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500 boul. de l'Université, Sherbrooke, QC, J1K 2R1, Canada
- Pharmacology Institute of Sherbrooke, Faculté de médecine et des sciences de la santé, 3001 12ième Avenue Nord, Sherbrooke, QC, J1H 5N4, Canada
- Research Centre on Aging, Institut universitaire de gériatrie de Sherbrooke, 1036 rue Belvédère Sud, Sherbrooke, QC, J1H 4C4, Canada
| | - Alexandre Poussard
- Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke, Dept. of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500 boul. de l'Université, Sherbrooke, QC, J1K 2R1, Canada
- Pharmacology Institute of Sherbrooke, Faculté de médecine et des sciences de la santé, 3001 12ième Avenue Nord, Sherbrooke, QC, J1H 5N4, Canada
- Research Centre on Aging, Institut universitaire de gériatrie de Sherbrooke, 1036 rue Belvédère Sud, Sherbrooke, QC, J1H 4C4, Canada
| | - Benoît Côté
- Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke, Dept. of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500 boul. de l'Université, Sherbrooke, QC, J1K 2R1, Canada
| | - Parker L Andersen
- Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke, Dept. of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500 boul. de l'Université, Sherbrooke, QC, J1K 2R1, Canada
- Pharmacology Institute of Sherbrooke, Faculté de médecine et des sciences de la santé, 3001 12ième Avenue Nord, Sherbrooke, QC, J1H 5N4, Canada
- Research Centre on Aging, Institut universitaire de gériatrie de Sherbrooke, 1036 rue Belvédère Sud, Sherbrooke, QC, J1H 4C4, Canada
| | - Patrick Vermette
- Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke, Dept. of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500 boul. de l'Université, Sherbrooke, QC, J1K 2R1, Canada
- Pharmacology Institute of Sherbrooke, Faculté de médecine et des sciences de la santé, 3001 12ième Avenue Nord, Sherbrooke, QC, J1H 5N4, Canada
- Research Centre on Aging, Institut universitaire de gériatrie de Sherbrooke, 1036 rue Belvédère Sud, Sherbrooke, QC, J1H 4C4, Canada
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28
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Hussain SS, Harris MT, Kreutzberger AJB, Inouye CM, Doyle CA, Castle AM, Arvan P, Castle JD. Control of insulin granule formation and function by the ABC transporters ABCG1 and ABCA1 and by oxysterol binding protein OSBP. Mol Biol Cell 2018. [PMID: 29540530 PMCID: PMC5935073 DOI: 10.1091/mbc.e17-08-0519] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In pancreatic β-cells, insulin granule membranes are enriched in cholesterol and are both recycled and newly generated. Cholesterol’s role in supporting granule membrane formation and function is poorly understood. ATP binding cassette transporters ABCG1 and ABCA1 regulate intracellular cholesterol and are important for insulin secretion. RNAi interference–induced depletion in cultured pancreatic β-cells shows that ABCG1 is needed to stabilize newly made insulin granules against lysosomal degradation; ABCA1 is also involved but to a lesser extent. Both transporters are also required for optimum glucose-stimulated insulin secretion, likely via complementary roles. Exogenous cholesterol addition rescues knockdown-induced granule loss (ABCG1) and reduced secretion (both transporters). Another cholesterol transport protein, oxysterol binding protein (OSBP), appears to act proximally as a source of endogenous cholesterol for granule formation. Its knockdown caused similar defective stability of young granules and glucose-stimulated insulin secretion, neither of which were rescued with exogenous cholesterol. Dual knockdowns of OSBP and ABC transporters support their serial function in supplying and concentrating cholesterol for granule formation. OSBP knockdown also decreased proinsulin synthesis consistent with a proximal endoplasmic reticulum defect. Thus, membrane cholesterol distribution contributes to insulin homeostasis at production, packaging, and export levels through the actions of OSBP and ABCs G1 and A1.
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Affiliation(s)
- Syed Saad Hussain
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Megan T Harris
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Alex J B Kreutzberger
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22908.,Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Candice M Inouye
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Catherine A Doyle
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Anna M Castle
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Peter Arvan
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - J David Castle
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908.,Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA 22908
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29
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Arunagiri A, Haataja L, Cunningham CN, Shrestha N, Tsai B, Qi L, Liu M, Arvan P. Misfolded proinsulin in the endoplasmic reticulum during development of beta cell failure in diabetes. Ann N Y Acad Sci 2018; 1418:5-19. [PMID: 29377149 DOI: 10.1111/nyas.13531] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/14/2017] [Accepted: 09/25/2017] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is broadly distributed throughout the cytoplasm of pancreatic beta cells, and this is where all proinsulin is initially made. Healthy beta cells can synthesize 6000 proinsulin molecules per second. Ordinarily, nascent proinsulin entering the ER rapidly folds via the formation of three evolutionarily conserved disulfide bonds (B7-A7, B19-A20, and A6-A11). A modest amount of proinsulin misfolding, including both intramolecular disulfide mispairing and intermolecular disulfide-linked protein complexes, is a natural by-product of proinsulin biosynthesis, as is the case for many proteins. The steady-state level of misfolded proinsulin-a potential ER stressor-is linked to (1) production rate, (2) ER environment, (3) presence or absence of naturally occurring (mutational) defects in proinsulin, and (4) clearance of misfolded proinsulin molecules. Accumulation of misfolded proinsulin beyond a certain threshold begins to interfere with the normal intracellular transport of bystander proinsulin, leading to diminished insulin production and hyperglycemia, as well as exacerbating ER stress. This is most obvious in mutant INS gene-induced Diabetes of Youth (MIDY; an autosomal dominant disease) but also likely to occur in type 2 diabetes owing to dysregulation in proinsulin synthesis, ER folding environment, or clearance.
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Affiliation(s)
- Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Corey N Cunningham
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan
| | - Neha Shrestha
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - Ling Qi
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Ming Liu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan.,Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
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30
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Zhang H, Zhong X, Huang Z, Huang C, Liu T, Qiu Y. Sulfonylurea for the treatment of neonatal diabetes owing to K ATP-channel mutations: a systematic review and meta-analysis. Oncotarget 2017; 8:108274-108285. [PMID: 29296240 PMCID: PMC5746142 DOI: 10.18632/oncotarget.22548] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 10/12/2017] [Indexed: 01/24/2023] Open
Abstract
The effect of sulfonylurea for the treatment of neonatal diabetes (NDM) is remain uncertain. We conducted this systematic review and meta-analysis to investigate the effect of sulfonylurea for NDM and to provide the latest and most convincing evidence for developing clinical practice guidelines of NDM. A literature review was performed to identify all published studies reporting the sulfonylurea on the treatment of neonatal diabetes. The search included the following databases: PUBMED, EMBASE and the Cochrane Library. The primary outcome was the success rates of treatment, change of glycosylated hemoglobin (HbA1c) and C-peptide. Data results were pooled by using MetaAnalyst with a random-effects model. Ten studies (6 cohort studies and 4 cross-sectional studies) involving 285 participants were included in the analysis. The pooled estimated success rate by the random-effects model was 90.1%(95% CI: 85.1%-93.5%). HbA1c had a significantly lower compared with before treatment. The pooled estimate of MD was -2.289, and the 95% CI was -2.790 to -1.789 (P < 0.001). The subgroup analysis showed a similar result for cohort studies and in cross-sectional studies. The common mild side effect is gastrointestinal reaction. The present meta-analysis suggested that sulfonylurea had a positive effect for treatment NDM due to KATP channel mutations. In addition, sulfonylurea also displayed sound safety except the mild gastrointestinal reaction. However, the findings rely chiefly on data from observational studies. Further well-conducted trials are required to assess sulfonylurea for NDM.
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Affiliation(s)
- Hongliang Zhang
- Pharmacy Department, The First Affiliated Hospital of Guangxi Medical University, 530021, Nanning, China.,Guangxi Key Laboratory of Regenerative Medicine, The First Affiliated Hospital of Guangxi Medical University, 530021, Nanning, China
| | - Xiaobin Zhong
- Guangxi Key Laboratory of Regenerative Medicine, The First Affiliated Hospital of Guangxi Medical University, 530021, Nanning, China
| | - Zhenguang Huang
- Pharmacy Department, The First Affiliated Hospital of Guangxi Medical University, 530021, Nanning, China
| | - Chun Huang
- Pharmacy Department, The First Affiliated Hospital of Guangxi Medical University, 530021, Nanning, China
| | - Taotao Liu
- Pharmacy Department, The First Affiliated Hospital of Guangxi Medical University, 530021, Nanning, China
| | - Yue Qiu
- Pharmacy Department, The First Affiliated Hospital of Guangxi Medical University, 530021, Nanning, China
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Raleigh D, Zhang X, Hastoy B, Clark A. The β-cell assassin: IAPP cytotoxicity. J Mol Endocrinol 2017; 59:R121-R140. [PMID: 28811318 DOI: 10.1530/jme-17-0105] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 08/15/2017] [Indexed: 12/28/2022]
Abstract
Islet amyloid polypeptide (IAPP) forms cytotoxic oligomers and amyloid fibrils in islets in type 2 diabetes (T2DM). The causal factors for amyloid formation are largely unknown. Mechanisms of molecular folding and assembly of human IAPP (hIAPP) into β-sheets, oligomers and fibrils have been assessed by detailed biophysical studies of hIAPP and non-fibrillogenic, rodent IAPP (rIAPP); cytotoxicity is associated with the early phases (oligomers/multimers) of fibrillogenesis. Interaction with synthetic membranes promotes β-sheet assembly possibly via a transient α-helical molecular conformation. Cellular hIAPP cytotoxicity can be activated from intracellular or extracellular sites. In transgenic rodents overexpressing hIAPP, intracellular pro-apoptotic signals can be generated at different points in β-cell protein synthesis. Increased cellular trafficking of proIAPP, failure of the unfolded protein response (UPR) or excess trafficking of misfolded peptide via the degradation pathways can induce apoptosis; these data indicate that defects in intracellular handling of hIAPP can induce cytotoxicity. However, there is no evidence for IAPP overexpression in T2DM. Extracellular amyloidosis is directly related to the degree of β-cell apoptosis in islets in T2DM. IAPP fragments, fibrils and multimers interact with membranes causing disruption in vivo and in vitro These findings support a role for extracellular IAPP in β-sheet conformation in cytotoxicity. Inhibitors of fibrillogenesis are useful tools to determine the aberrant mechanisms that result in hIAPP molecular refolding and islet amyloidosis. However, currently, their role as therapeutic agents remains uncertain.
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Affiliation(s)
- Daniel Raleigh
- Department of ChemistryStony Brook University, Stony Brook, New York, USA
- Research Department of Structural and Molecule BiologyUniversity College London, London, UK
| | - Xiaoxue Zhang
- Department of ChemistryStony Brook University, Stony Brook, New York, USA
| | - Benoît Hastoy
- Oxford Centre for Diabetes Endocrinology and MetabolismUniversity of Oxford, Oxford, UK
| | - Anne Clark
- Oxford Centre for Diabetes Endocrinology and MetabolismUniversity of Oxford, Oxford, UK
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Cunningham CN, He K, Arunagiri A, Paton AW, Paton JC, Arvan P, Tsai B. Chaperone-Driven Degradation of a Misfolded Proinsulin Mutant in Parallel With Restoration of Wild-Type Insulin Secretion. Diabetes 2017; 66:741-753. [PMID: 28028074 PMCID: PMC5319713 DOI: 10.2337/db16-1338] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/20/2016] [Indexed: 02/06/2023]
Abstract
In heterozygous patients with a diabetic syndrome called mutant INS gene-induced diabetes of youth (MIDY), there is decreased insulin secretion when mutant proinsulin expression prevents wild-type (WT) proinsulin from exiting the endoplasmic reticulum (ER), which is essential for insulin production. Our previous results revealed that mutant Akita proinsulin is triaged by ER-associated degradation (ERAD). We now find that the ER chaperone Grp170 participates in the degradation process by shifting Akita proinsulin from high-molecular weight (MW) complexes toward smaller oligomeric species that are competent to undergo ERAD. Strikingly, overexpressing Grp170 also liberates WT proinsulin, which is no longer trapped in these high-MW complexes, enhancing ERAD of Akita proinsulin and restoring WT insulin secretion. Our data reveal that Grp170 participates in preparing mutant proinsulin for degradation while enabling WT proinsulin escape from the ER. In principle, selective destruction of mutant proinsulin offers a rational approach to rectify the insulin secretion problem in MIDY.
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Affiliation(s)
- Corey N Cunningham
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI
| | - Kaiyu He
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Anoop Arunagiri
- Division of Metabolism Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Adrienne W Paton
- Research Centre for Infectious Diseases, Department of Molecular and Cellular Biology, University of Adelaide, Adelaide, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Cellular Biology, University of Adelaide, Adelaide, Australia
| | - Peter Arvan
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI
- Division of Metabolism Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Billy Tsai
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI
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Li WH. Probes for monitoring regulated exocytosis. Cell Calcium 2017; 64:65-71. [PMID: 28089267 DOI: 10.1016/j.ceca.2017.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 01/07/2017] [Indexed: 12/12/2022]
Abstract
Regulated secretion is a fundamental cellular process that serves diverse functions in neurobiology, endocrinology, immunology, and numerous other aspects of animal physiology. In response to environmental or biological cues, cells release contents of secretory granules into an extracellular medium to communicate with or impact neighboring or distant cells through paracrine or endocrine signaling. To investigate mechanisms governing stimulus-secretion coupling, to better understand how cells maintain or regulate their secretory activity, and to characterize secretion defects in human diseases, probes for tracking various exocytotic events at the cellular or sub-cellular level have been developed over the years. This review summarizes different strategies and recent progress in developing optical probes for monitoring regulated secretion in mammalian cells.
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Affiliation(s)
- Wen-Hong Li
- Departments of Cell Biology and of Biochemistry, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 75390-9039, United States.
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Affiliation(s)
- Mark A Rizzo
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD
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Markwardt ML, Seckinger KM, Rizzo MA. Regulation of Glucokinase by Intracellular Calcium Levels in Pancreatic β Cells. J Biol Chem 2015; 291:3000-9. [PMID: 26698632 DOI: 10.1074/jbc.m115.692160] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Indexed: 01/01/2023] Open
Abstract
Glucokinase (GCK) controls the rate of glucose metabolism in pancreatic β cells, and its activity is rate-limiting for insulin secretion. Posttranslational GCK activation can be stimulated through either G protein-coupled receptors or receptor tyrosine kinase signaling pathways, suggesting a common mechanism. Here we show that inhibiting Ca(2+) release from the endoplasmic reticulum (ER) decouples GCK activation from receptor stimulation. Furthermore, pharmacological release of ER Ca(2+) stimulates activation of a GCK optical biosensor and potentiates glucose metabolism, implicating rises in cytoplasmic Ca(2+) as a critical regulatory mechanism. To explore the potential for glucose-stimulated GCK activation, the GCK biosensor was optimized using circularly permuted mCerulean3 proteins. This new sensor sensitively reports activation in response to insulin, glucagon-like peptide 1, and agents that raise cAMP levels. Transient, glucose-stimulated GCK activation was observed in βTC3 and MIN6 cells. An ER-localized channelrhodopsin was used to manipulate the cytoplasmic Ca(2+) concentration in cells expressing the optimized FRET-GCK sensor. This permitted quantification of the relationship between cytoplasmic Ca(2+) concentrations and GCK activation. Half-maximal activation of the FRET-GCK sensor was estimated to occur at ∼400 nm Ca(2+). When expressed in islets, fluctuations in GCK activation were observed in response to glucose, and we estimated that posttranslational activation of GCK enhances glucose metabolism by ∼35%. These results suggest a mechanism for integrative control over GCK activation and, therefore, glucose metabolism and insulin secretion through regulation of cytoplasmic Ca(2+) levels.
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Affiliation(s)
- Michele L Markwardt
- From the University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Kendra M Seckinger
- From the University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Mark A Rizzo
- From the University of Maryland School of Medicine, Baltimore, Maryland 21201
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