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Yao C, Zhuang H, Cheng W, Lin Y, Du P, Yang B, Huang X, Chen S, Hu Q, Hua ZC. FADD phosphorylation impaired islet morphology and function. J Cell Physiol 2015; 230:1448-56. [PMID: 25641109 DOI: 10.1002/jcp.24885] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 11/26/2014] [Indexed: 11/06/2022]
Abstract
Previous studies have indicated that Fas-FasL pathway and its downstream caspase-8 can regulate islet mass and insulin secretion. As a classical adaptor in Fas-FasL signaling, Fas-associated death domain-containing protein (FADD) takes part in many non-apoptosis processes regulated by its phosphorylation. However, its role in islets has not been evaluated to date. Here, through comparative proteomics and bioinformatic analysis on FADD phosphorylated (FADD-D) and wild-type (WT) MEFs, we found three proteins involved in islet differentiation and function were dysregulated due to FADD phosphorylation. The mouse model of FADD-D, which mimics constitutive phosphorylated FADD expression in mice, was further analyzed to address this issue. We confirmed the proteomic results by immunohistological analyses on pancreatic islets. In addition, we found that FADD-D mice displayed decreased islet area, and the glucose stimulated insulin secretion (GSIS) of FADD-D islets was impaired. These data suggest a novel role of FADD in islet development and insulin secretion.
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Affiliation(s)
- Chun Yao
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Stomatology and Affiliated Stomatological Hospital, Nanjing University, Nanjing, 210093, P. R. China
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Morphological changes of post-isolation of caprine pancreatic islet. In Vitro Cell Dev Biol Anim 2014; 51:113-20. [DOI: 10.1007/s11626-014-9821-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 09/10/2014] [Indexed: 01/04/2023]
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Abstract
OBJECTIVES The canine model has been used extensively to improve the human pancreatic islet isolation technique. At the functional level, dog islets show high similarity to human islets and thus can be a helpful tool for islet research. We describe and compare 2 manual isolation methods, M1 (initial) and M2 (modified), and analyze the variables associated with the outcomes, including islet yield, purity, and glucose-stimulated insulin secretion (GSIS). METHODS Male mongrel dogs were used in the study. M2 (n = 7) included higher collagenase concentration, shorter digestion time, faster shaking speed, colder purification temperature, and higher differential density gradient than M1 (n = 7). RESULTS Islet yield was similar between methods (3111.0 ± 309.1 and 3155.8 ± 644.5 islets/g, M1 and M2, respectively; P = 0.951). Pancreas weight and purity together were directly associated with the yield (adjusted R(2) = 0.61; P = 0.002). Purity was considerably improved with M2 (96.7% ± 1.2% vs 75.0% ± 6.3%; P = 0.006). M2 improved GSIS (P = 0.021). Independently, digestion time was inversely associated with GSIS. CONCLUSIONS We describe an isolation method (M2) to obtain a highly pure yield of dog islets with adequate β-cell glucose responsiveness. The isolation variables associated with the outcomes in our canine model confirm previous reports in other species, including humans.
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Carter JD, Dula SB, Corbin KL, Wu R, Nunemaker CS. A practical guide to rodent islet isolation and assessment. Biol Proced Online 2009; 11:3-31. [PMID: 19957062 PMCID: PMC3056052 DOI: 10.1007/s12575-009-9021-0] [Citation(s) in RCA: 202] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Accepted: 10/22/2009] [Indexed: 11/25/2022] Open
Abstract
Pancreatic islets of Langerhans secrete hormones that are vital to the regulation of blood glucose and are, therefore, a key focus of diabetes research. Purifying viable and functional islets from the pancreas for study is an intricate process. This review highlights the key elements involved with mouse and rat islet isolation, including choices of collagenase, the collagenase digestion process, purification of islets using a density gradient, and islet culture conditions. In addition, this paper reviews commonly used techniques for assessing islet viability and function, including visual assessment, fluorescent markers of cell death, glucose-stimulated insulin secretion, and intracellular calcium measurements. A detailed protocol is also included that describes a common method for rodent islet isolation that our laboratory uses to obtain viable and functional mouse islets for in vitro study of islet function, beta-cell physiology, and in vivo rodent islet transplantation. The purpose of this review is to serve as a resource and foundation for successfully procuring and purifying high-quality islets for research purposes.
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Affiliation(s)
- Jeffrey D Carter
- Department of Medicine, Division of Endocrinology, University of Virginia, P.O. Box 801413, Charlottesville, VA, 22908, USA
- DERC Cell and Islet Isolation Core Facility, University of Virginia, Charlottesville, VA, USA
| | - Stacey B Dula
- Department of Medicine, Division of Endocrinology, University of Virginia, P.O. Box 801413, Charlottesville, VA, 22908, USA
| | - Kathryn L Corbin
- Department of Medicine, Division of Endocrinology, University of Virginia, P.O. Box 801413, Charlottesville, VA, 22908, USA
- DERC Cell and Islet Isolation Core Facility, University of Virginia, Charlottesville, VA, USA
| | - Runpei Wu
- Department of Medicine, Division of Endocrinology, University of Virginia, P.O. Box 801413, Charlottesville, VA, 22908, USA
| | - Craig S Nunemaker
- Department of Medicine, Division of Endocrinology, University of Virginia, P.O. Box 801413, Charlottesville, VA, 22908, USA
- DERC Cell and Islet Isolation Core Facility, University of Virginia, Charlottesville, VA, USA
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Morini S, Brown ML, Cicalese L, Elias G, Carotti S, Gaudio E, Rastellini C. Revascularization and remodelling of pancreatic islets grafted under the kidney capsule. J Anat 2007; 210:565-77. [PMID: 17394557 PMCID: PMC2375740 DOI: 10.1111/j.1469-7580.2007.00717.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The revascularization and the structural changes resulting from interactions between the graft and the host were investigated in transplanted pancreatic islets under the kidney capsule. Islets were isolated from mice pancreata and transplanted in syngeneic diabetic animals. Graft-bearing kidneys were collected on different days post-transplant and processed for light microscopy, immunohistochemistry and transmission electron microscopy. A numerical analysis was performed in order to compare the percentage number of the different types of cells in native islets and at different time points after the transplant. Recipient animals reversed diabetes within 4 days. An intraperitoneal glucose tolerance test was performed to determine islet functionality under stressful conditions. During the initial few days post-transplant, the islets showed peculiar shapes and the graft tended to aggregate along the vessels. Starting at days 4-7 post-transplant, islets were revascularized from vessels connected to both the cortical and the capsular vascular network of the kidney. From day 7-14 post-transplant, the vessels progressively appeared more similar in features and size to those of in situ pancreatic islets. Both the percentage number of the different cell types and the distribution of Alpha, Beta and Delta cells inside the graft were significantly different as compared with intact islets, demonstrating quantitative and structural changes after the engraftment. No concomitant proliferation of Beta cells was detected using a bromodeoxyuridin staining method. Despite the fact that quick revascularization preserved a large mass of tissue, the remodelling process of the graft and the newly formed vascularization led to a different organization of the endocrine tissue as compared with intact in situ islets. This constitutes the morphological basis for alterations of the normal intercellular interactions and may explain the altered secretory cell function often observed in transplant.
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Affiliation(s)
- Sergio Morini
- Department of Biomedical Research (CIR), University Campus Bio-MedicoRome, Italy
| | - Melissa L Brown
- Department of Surgery, Division of Transplantation, University of MassachusettsWorchester, MA, USA
| | - Luca Cicalese
- Department of Surgery, Division of Transplantation, University of MassachusettsWorchester, MA, USA
| | - George Elias
- Department of Surgery, Division of Transplantation, University of MassachusettsWorchester, MA, USA
| | - Simone Carotti
- Department of Biomedical Research (CIR), University Campus Bio-MedicoRome, Italy
| | - Eugenio Gaudio
- Department of Biomedical Research (CIR), University Campus Bio-MedicoRome, Italy
- Department of Human Anatomy, University of Rome‘La Sapienza’, Italy
| | - Cristiana Rastellini
- Department of Surgery, Division of Transplantation, University of MassachusettsWorchester, MA, USA
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Affiliation(s)
- Federico Bertuzzi
- The Meditterranean Institute for Transplantation and Advanced Specialized Therapies, via Tricomi 1, Palermo, Italy.
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Morini S, Braun M, Onori P, Cicalese L, Elias G, Gaudio E, Rastellini C. Morphological changes of isolated rat pancreatic islets: a structural, ultrastructural and morphometric study. J Anat 2007; 209:381-92. [PMID: 16928206 PMCID: PMC2100330 DOI: 10.1111/j.1469-7580.2006.00620.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Improved techniques for pancreatic islet extraction can yield a reasonable number of transplantable cells. However, the isolation and purification process may damage the islets and impair their physiological functions. The aim of this study was to determine the effect of the isolation procedure on the structure of isolated islets and to correlate this with their functionality. Islets were isolated from rat pancreata and purified by Eurocollins-Ficoll discontinuous density gradient processing, and then processed for light microscopy, and scanning and transmission electron microscopy. Morphometric analysis was also performed. Islet functionality was determined by reversal of streptozotocin-induced diabetes and the intraperitoneal glucose tolerance test in a syngeneic rat model of pancreatic islet transplantation. Fragments of variable size and shape comprised a relatively large proportion (26%) of the isolated endocrine tissue. Isolated islets showed slight alterations of cell ultrastructure. Major damage (including breakage of the plasma membrane) and loss of cells were observed in the peripheral cells of the isolated islets. An equal mass of islet equivalent (IEq, islets with an average diameter of 150 microm), but with a different islet equivalent/islet number ratio, was transplanted in diabetic animals. When larger and more complete islets were transplanted (higher ratio), better function of the graft was observed by reversal of hyperglycaemia and response to the glucose tolerance test as compared with the functionality and response of smaller (fragmented) islets transplanted (lower ratio). Digestion, trauma and hypoxia during isolation are responsible for qualitative and quantitative changes of isolated islets. Alterations in normal secretory function after the transplant were related to lower islet equivalent/islet number ratio. The incomplete integrity of the islets may explain the failure of the fine glycaemic metabolic regulation.
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Affiliation(s)
- Sergio Morini
- Department of Biomedical Researches (CIR), University Campus Bio-MedicoRome, Italy
| | - Mark Braun
- Department of Surgery, University of IllinoisChicago, IL, USA
| | - Paolo Onori
- Department of Experimental Medicine, University of L'AquilaItaly
| | - Luca Cicalese
- Department of Surgery, Division of Transplantation, University of MassachusettsWorchester, MA, USA
| | - George Elias
- Department of Surgery, Division of Transplantation, University of MassachusettsWorchester, MA, USA
| | - Eugenio Gaudio
- Department of Biomedical Researches (CIR), University Campus Bio-MedicoRome, Italy
- Department of Human Anatomy, University of Rome‘La Sapienza’, Italy
| | - Cristiana Rastellini
- Department of Surgery, Division of Transplantation, University of MassachusettsWorchester, MA, USA
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Anello M, Lupi R, Spampinato D, Piro S, Masini M, Boggi U, Del Prato S, Rabuazzo AM, Purrello F, Marchetti P. Functional and morphological alterations of mitochondria in pancreatic beta cells from type 2 diabetic patients. Diabetologia 2005; 48:282-9. [PMID: 15654602 DOI: 10.1007/s00125-004-1627-9] [Citation(s) in RCA: 280] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Accepted: 09/04/2004] [Indexed: 12/20/2022]
Abstract
AIMS/HYPOTHESIS Little information is available on the insulin release properties of pancreatic islets isolated from type 2 diabetic subjects. Since mitochondria represent the site where important metabolites that regulate insulin secretion are generated, we studied insulin release as well as mitochondrial function and morphology directly in pancreatic islets isolated from type 2 diabetic patients. METHODS Islets were prepared by collagenase digestion and density gradient purification, and insulin secretion in response to glucose and arginine was assessed by the batch incubation method. Adenine nucleotides, mitochondrial membrane potential, the expression of UCP-2, complex I and complex V of the respiratory chain, and nitrotyrosine levels were evaluated and correlated with insulin secretion. RESULTS Compared to control islets, diabetic islets showed reduced insulin secretion in response to glucose, and this defect was associated with lower ATP levels, a lower ATP/ADP ratio and impaired hyperpolarization of the mitochondrial membrane. Increased protein expression of UCP-2, complex I and complex V of the respiratory chain, and a higher level of nitrotyrosine were also found in type 2 diabetic islets. Morphology studies showed that control and diabetic beta cells had a similar number of mitochondria; however, mitochondrial density volume was significantly higher in type 2 diabetic beta cells. CONCLUSIONS/INTERPRETATION In pancreatic beta cells from type 2 diabetic subjects, the impaired secretory response to glucose is associated with a marked alteration of mitochondrial function and morphology. In particular, UCP-2 expression is increased (probably due to a condition of fuel overload), which leads to lower ATP, decreased ATP/ADP ratio, with consequent reduction of insulin release.
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Affiliation(s)
- M Anello
- Internal Medicine, Department of Internal and Specialistic Medicine, University of Catania, Ospedale Cannizzaro, Catania, Italy
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Song MK, Levin SR. Metabolism of glucose by rat pancreatic islets and kidney: comparison of membrane preparations with intact tissue. Pancreas 2002; 24:205-9. [PMID: 11854627 DOI: 10.1097/00006676-200203000-00013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
INTRODUCTION Insulin secretion in the pancreatic islet of Langerhans is closely related to glucose oxidation. Our previous membrane preparations from the islet of Langerhans and kidney contained Na+/K+ ATPase. Although ATP is a modulator of insulin release, we have not demonstrated that membranes contain glycolytic enzymes. AIMS To compare glucose oxidation in intact islets of Langerhans with that seen in islet membranes, and to examine renal tissue because of easy access to this tissue and because our previous work contrasted islets and kidney Na+/K+ ATPase activity. METHODOLOGY To examine whether membrane preparations of both islets and kidney contain glycolytic activity, we designed an apparatus that determines tissue glucose oxidation rates by measuring 14CO2 production from 14C-1-D-glucose. In contrast to previous methods, O2 was supplied and pH was maintained in physiologic ranges throughout the incubations. RESULTS At 5.5 mM glucose, oxidation was linear over 2 hours in intact islets and kidney. Islets produced approximately twice the 14CO2 as kidney, or 1000 nmol CO2/mg protein/hour. Membranes oxidized glucose at less than 10% of the rates observed with intact tissue. Concentration dependency was linear from 0-11.0 mM glucose; however, at 16.5 mM, oxidation decreased to less than half of that seen at 11.0 mM. CONCLUSION Our "membrane" preparations contain some glycolytic activity but are unlikely to contribute significant amounts of ATP in most studies of ATP hydrolysis, such as that seen in experiments that measure ATPase activity.
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Affiliation(s)
- Moon K Song
- Diabetes Research Laboratory, Medical and Research Services, West LA VA Medical Center, 11301 Wilshire Boulevard, Los Angeles, CA 90073, U.S.A
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