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Lofrumento DD, Miraglia A, La Pesa V, Treglia AS, Chieppa M, De Nuccio F, Nicolardi G, Miele C, Beguinot F, Garbi C, Di Jeso B. Increased hexosamine biosynthetic pathway flux alters cell-cell adhesion in INS-1E cells and murine islets. Endocrine 2023; 81:492-502. [PMID: 37306934 PMCID: PMC10403402 DOI: 10.1007/s12020-023-03412-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 05/28/2023] [Indexed: 06/13/2023]
Abstract
PURPOSE In type 2 Diabetes, β-cell failure is caused by loss of cell mass, mostly by apoptosis, but also by simple dysfunction (dedifferentiation, decline of glucose-stimulated insulin secretion). Apoptosis and dysfunction are caused, at least in part, by glucotoxicity, in which increased flux of glucose in the hexosamine biosynthetic pathway plays a role. In this study, we sought to clarify whether increased hexosamine biosynthetic pathway flux affects another important aspect of β-cell physiology, that is β-cell-β-cell homotypic interactions. METHODS We used INS-1E cells and murine islets. The expression and cellular distribution of E-cadherin and β-catenin was evaluated by immunofluorescence, immunohistochemistry and western blot. Cell-cell adhesion was examined by the hanging-drop aggregation assay, islet architecture by isolation and microscopic observation. RESULTS E-cadherin expression was not changed by increased hexosamine biosynthetic pathway flux, however, there was a decrease of cell surface, and an increase in intracellular E-cadherin. Moreover, intracellular E-cadherin delocalized, at least in part, from the Golgi complex to the endoplasmic reticulum. Beta-catenin was found to parallel the E-cadherin redistribution, showing a dislocation from the plasmamembrane to the cytosol. These changes had as a phenotypic consequence a decreased ability of INS-1E to aggregate. Finally, in ex vivo experiments, glucosamine was able to alter islet structure and to decrease surface abundandance of E-cadherin and β-catenin. CONCLUSION Increased hexosamine biosynthetic pathway flux alters E-cadherin cellular localization both in INS-1E cells and murine islets and affects cell-cell adhesion and islet morphology. These changes are likely caused by alterations of E-cadherin function, highlighting a new potential target to counteract the consequences of glucotoxicity on β-cells.
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Affiliation(s)
| | - Alessandro Miraglia
- DiSTeBA, Centro Ecotekne, Strada Monteroni, University of Salento, 73100, Lecce, Italy
| | - Velia La Pesa
- Institute of Experimental Neurology and Division of Neuroscience, Neuropathology Unit, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy
| | | | - Marcello Chieppa
- DiSTeBA, Centro Ecotekne, Strada Monteroni, University of Salento, 73100, Lecce, Italy
| | - Francesco De Nuccio
- DiSTeBA, Centro Ecotekne, Strada Monteroni, University of Salento, 73100, Lecce, Italy
| | - Giuseppe Nicolardi
- DiSTeBA, Centro Ecotekne, Strada Monteroni, University of Salento, 73100, Lecce, Italy
| | - Claudia Miele
- CNR, IEOS and DiSMeT, Via S. Pansini 5, University "Federico II", Naples, Italy
| | - Francesco Beguinot
- CNR, IEOS and DiSMeT, Via S. Pansini 5, University "Federico II", Naples, Italy
| | - Corrado Garbi
- Dip. Medicina Molecolare e Biotecnologie Mediche, Via S. Pansini 5, University "Federico II", Naples, Italy
| | - Bruno Di Jeso
- DiSTeBA, Centro Ecotekne, Strada Monteroni, University of Salento, 73100, Lecce, Italy.
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Ramamoorthy S, Garg S, Mishra B, Radotra BD, Saikia UN. Coxsackievirus and Adenovirus Receptor (CAR) Expression in Autopsy Tissues: Organ-Specific Patterns and Clinical Significance. Cureus 2023; 15:e37138. [PMID: 37153286 PMCID: PMC10159945 DOI: 10.7759/cureus.37138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2023] [Indexed: 05/09/2023] Open
Abstract
Coxsackievirus and adenovirus receptor (CAR) homologs have been identified in many species, and their proteins appeared to be highly conserved in evolution. While most of the human studies are about pathological conditions, the animal studies were more about the physiological and developmental functions of receptors. The expression of CAR is developmentally regulated, and its tissue localization is complex. Hence, we planned to study CAR expression in five different human organs at autopsy in different age groups. CAR expression was analyzed in the pituitary, heart, liver, pancreas, and kidney by immunohistochemistry, and CAR mRNA expression in the heart and pituitary by real-time PCR. In the current study, CAR expression was strong in cells of the anterior pituitary, hepatocytes, and bile ducts in the liver, acini, and pancreas and distal convoluted tubule/collecting duct in the kidney, with uniform expression in all age groups. We have noted high CAR expression in fetuses and infantile hearts, which get reduced drastically in adults due to its presumed developmental role in intrauterine life studied in animal models. In addition, the receptor was expressed in glomerular podocytes around the period of fetus viability (37 weeks) but not in early fetuses and adults. We have hypothesized that this intermittent expression could be responsible for the intercellular contact normally formed between the podocytes during the developmental phase. Pancreatic islets also showed increased expression after the emergence of the viability period but not in early fetuses and adults, which might be related to an increase in fetal insulin secretion at that particular age group.
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Affiliation(s)
| | - Sumit Garg
- Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, IND
| | - Baijayantimala Mishra
- Department of Microbiology, All India Institute of Medical Sciences, Bhubaneswar, Bhubaneswar, IND
| | - Bishan Dass Radotra
- Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, IND
| | - Uma Nahar Saikia
- Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, IND
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Martinez C, Maschio DA, de Fontes CC, Vanzela EC, Benfato ID, Gazarini ML, Carneiro EM, de Oliveira CA, Collares-Buzato CB, de F. Carvalho CP. EARLY DECREASE IN CX36 IS ASSOCIATED WITH INCREASED CELL ADHESION MOLECULES (CAMs) JUNCTIONAL CONTENT IN MOUSE PANCREATIC ISLETS AFTER SHORT-TERM HIGH-FAT DIET FEEDING. Ann Anat 2022; 241:151891. [DOI: 10.1016/j.aanat.2022.151891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 11/29/2022]
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Ng XW, Chung YH, Piston DW. Intercellular Communication in the Islet of Langerhans in Health and Disease. Compr Physiol 2021; 11:2191-2225. [PMID: 34190340 PMCID: PMC8985231 DOI: 10.1002/cphy.c200026] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Blood glucose homeostasis requires proper function of pancreatic islets, which secrete insulin, glucagon, and somatostatin from the β-, α-, and δ-cells, respectively. Each islet cell type is equipped with intrinsic mechanisms for glucose sensing and secretory actions, but these intrinsic mechanisms alone cannot explain the observed secretory profiles from intact islets. Regulation of secretion involves interconnected mechanisms among and between islet cell types. Islet cells lose their normal functional signatures and secretory behaviors upon dispersal as compared to intact islets and in vivo. In dispersed islet cells, the glucose response of insulin secretion is attenuated from that seen from whole islets, coordinated oscillations in membrane potential and intracellular Ca2+ activity, as well as the two-phase insulin secretion profile, are missing, and glucagon secretion displays higher basal secretion profile and a reverse glucose-dependent response from that of intact islets. These observations highlight the critical roles of intercellular communication within the pancreatic islet, and how these communication pathways are crucial for proper hormonal and nonhormonal secretion and glucose homeostasis. Further, misregulated secretions of islet secretory products that arise from defective intercellular islet communication are implicated in diabetes. Intercellular communication within the islet environment comprises multiple mechanisms, including electrical synapses from gap junctional coupling, paracrine interactions among neighboring cells, and direct cell-to-cell contacts in the form of juxtacrine signaling. In this article, we describe the various mechanisms that contribute to proper islet function for each islet cell type and how intercellular islet communications are coordinated among the same and different islet cell types. © 2021 American Physiological Society. Compr Physiol 11:2191-2225, 2021.
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Affiliation(s)
- Xue W Ng
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - Yong H Chung
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - David W Piston
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
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Lien YC, Won KJ, Simmons RA. Transcriptomic and Quantitative Proteomic Profiling Reveals Signaling Pathways Critical for Pancreatic Islet Maturation. Endocrinology 2020; 161:5923720. [PMID: 33053583 PMCID: PMC7668240 DOI: 10.1210/endocr/bqaa187] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Indexed: 02/07/2023]
Abstract
Pancreatic β-cell dysfunction and reduced insulin secretion play a key role in the pathogenesis of diabetes. Fetal and neonatal islets are functionally immature and have blunted glucose responsiveness and decreased insulin secretion in response to stimuli and are far more proliferative. However, the mechanisms underlying functional immaturity are not well understood. Pancreatic islets are composed of a mixture of different cell types, and the microenvironment of islets and interactions between these cell types are critical for β-cell development and maturation. RNA sequencing and quantitative proteomic data from intact islets isolated from fetal (embryonic day 19) and 2-week-old Sprague-Dawley rats were integrated to compare their gene and protein expression profiles. Ingenuity Pathway Analysis (IPA) was also applied to elucidate pathways and upstream regulators modulating functional maturation of islets. By integrating transcriptome and proteomic data, 917 differentially expressed genes/proteins were identified with a false discovery rate of less than 0.05. A total of 411 and 506 of them were upregulated and downregulated in the 2-week-old islets, respectively. IPA revealed novel critical pathways associated with functional maturation of islets, such as AMPK (adenosine monophosphate-activated protein kinase) and aryl hydrocarbon receptor signaling, as well as the importance of lipid homeostasis/signaling and neuronal function. Furthermore, we also identified many proteins enriched either in fetal or 2-week-old islets related to extracellular matrix and cell communication, suggesting that these pathways play critical roles in islet maturation. Our present study identified novel pathways for mature islet function in addition to confirming previously reported mechanisms, and provided new mechanistic insights for future research on diabetes prevention and treatment.
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Affiliation(s)
- Yu-Chin Lien
- Center for Research on Reproduction and Women’s Health, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Neonatology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Kyoung-Jae Won
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rebecca A Simmons
- Center for Research on Reproduction and Women’s Health, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Neonatology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Correspondence: Rebecca A. Simmons, MD, Center for Research on Reproduction and Women’s Health, Perelman School of Medicine, the University of Pennsylvania, BRB II/III, 13th Fl, Rm 1308, 421 Curie Blvd, Philadelphia, PA 19104, USA. E-mail:
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Altered Transcription Factor Binding and Gene Bivalency in Islets of Intrauterine Growth Retarded Rats. Cells 2020; 9:cells9061435. [PMID: 32527043 PMCID: PMC7348746 DOI: 10.3390/cells9061435] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/30/2020] [Accepted: 06/04/2020] [Indexed: 12/16/2022] Open
Abstract
Intrauterine growth retardation (IUGR), which induces epigenetic modifications and permanent changes in gene expression, has been associated with the development of type 2 diabetes. Using a rat model of IUGR, we performed ChIP-Seq to identify and map genome-wide histone modifications and gene dysregulation in islets from 2- and 10-week rats. IUGR induced significant changes in the enrichment of H3K4me3, H3K27me3, and H3K27Ac marks in both 2-wk and 10-wk islets, which were correlated with expression changes of multiple genes critical for islet function in IUGR islets. ChIP-Seq analysis showed that IUGR-induced histone mark changes were enriched at critical transcription factor binding motifs, such as C/EBPs, Ets1, Bcl6, Thrb, Ebf1, Sox9, and Mitf. These transcription factors were also identified as top upstream regulators in our previously published transcriptome study. In addition, our ChIP-seq data revealed more than 1000 potential bivalent genes as identified by enrichment of both H3K4me3 and H3K27me3. The poised state of many potential bivalent genes was altered by IUGR, particularly Acod1, Fgf21, Serpina11, Cdh16, Lrrc27, and Lrrc66, key islet genes. Collectively, our findings suggest alterations of histone modification in key transcription factors and genes that may contribute to long-term gene dysregulation and an abnormal islet phenotype in IUGR rats.
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de Oliveira RB, Matheus VA, Canuto LP, De Sant'ana A, Collares-Buzato CB. Time-dependent alteration to the tight junction structure of distal intestinal epithelia in type 2 prediabetic mice. Life Sci 2019; 238:116971. [PMID: 31634462 DOI: 10.1016/j.lfs.2019.116971] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 10/13/2019] [Accepted: 10/14/2019] [Indexed: 01/18/2023]
Abstract
AIM High-fat diet (HFD) intake has been associated with changes in intestinal microbiota composition, increased intestinal permeability, and onset of type 2 diabetes mellitus (T2DM). The aim of this work was twofold: 1) to investigate the structural and functional alterations of the tight junction (TJ)-mediated intestinal epithelial barrier of ileum and colon, that concentrate most of the microbiota, after exposure to a HFD for 15, 30 and 60 days, and 2) to assess the effect of in vitro exposure to free fatty acids (FFAs), one of the components of HFD, on paracellular barrier of colon-derived Caco-2 cells. METHODS/KEY FINDINGS HFD exposure induced progressive metabolic changes in male mice that culminated in prediabetes after 60d. Morphological analysis of ileum and colon mucosa showed no signs of epithelial rupture or local inflammation but changes in the junctional content/distribution and/or cellular content of TJ-associated proteins (claudins-1, -2, -3, and occludin) in intestinal epithelia were seen mainly after a prediabetes state has been established. This impairment in TJ structure was not associated with significant changes in intestinal permeability to FITC-dextran. Exposure of Caco-2 monolayers to palmitic or linoleic acids seems to induce a reinforcement of TJ structure while treatment with oleic acid had a more diverse effect on TJ protein distribution. SIGNIFICANCE TJ structure in distal intestinal epithelia can be specifically impaired by HFD intake at early stage of T2DM, but not by FFAs in vitro. Since the TJ change in ileum/colon was marginal, probably it does not contribute to the disease onset.
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Affiliation(s)
- Ricardo Beltrame de Oliveira
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Valquiria Aparecida Matheus
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Leandro Pereira Canuto
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Ariane De Sant'ana
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Carla Beatriz Collares-Buzato
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil.
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Wang Z, Peng L, Song YL, Xu S, Hua Z, Fang N, Zhai M, Liu H, Fang Q, Deng T, Zhang W, Chen YJ, Lou J. Pseudo-hemorrhagic region formation in pancreatic neuroendocrine tumors is a result of blood vessel dilation followed by endothelial cell detachment. Oncol Lett 2018. [PMID: 29541192 PMCID: PMC5835859 DOI: 10.3892/ol.2018.7840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Aberrant blood vessel formation and hemorrhage may contribute to tumor progression and are potential targets in the treatment of several types of cancer. Pancreatic neuroendocrine tumors (PNETs) are highly vascularized, particularly when they are well-differentiated. However, the process of vascularization and endothelial cell detachment in PNETs is poorly understood. In the present study, 132 PNET clinical samples were examined and a special type of hemorrhagic region was observed in ~30% of the samples regardless of tumor subtype. These hemorrhagic regions were presented as blood-filled caverns with a smooth boundary and were unlined by endothelial cells. Based on the extensive endothelial cell detachment observed in the clinical samples, the formation process of these blood-filled caverns was hypothesized. Blood vessel dilation followed by detachment of endothelial cells from the surrounding tumor tissue was speculated. This was further supported using an INS-1 xenograft insulinoma model. As the formation process was distinct from the typical diffusive hemorrhage, it was named ‘pseudo-hemorrhage’. Furthermore, it was demonstrated that epithelial (E-) cadherin and β-catenin were overexpressed in tumor cells surrounding these pseudo-hemorrhagic regions. Therefore, even though no statistically significant association of pseudo-hemorrhage with clinical features (metastasis or disease recurrence) was identified, the high levels of E-cadherin and β-catenin expression may suggest that a number of features of normal islet cells are retained.
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Affiliation(s)
- Zai Wang
- Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Chaoyang, Beijing 100029, P.R. China
| | - Liang Peng
- Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Chaoyang, Beijing 100029, P.R. China
| | - Yu-Li Song
- Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, P.R. China
| | - Shiqing Xu
- Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Chaoyang, Beijing 100029, P.R. China
| | - Zhan Hua
- Department of General Surgery, China-Japan Friendship Hospital, Chaoyang, Beijing 100029, P.R. China
| | - Ni Fang
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing 100102, P.R. China
| | - Min Zhai
- Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Chaoyang, Beijing 100029, P.R. China
| | - Honglin Liu
- Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Chaoyang, Beijing 100029, P.R. China
| | - Qing Fang
- Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Chaoyang, Beijing 100029, P.R. China
| | - Tingting Deng
- Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Chaoyang, Beijing 100029, P.R. China
| | - Wenjian Zhang
- Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Chaoyang, Beijing 100029, P.R. China
| | - Yuan-Jia Chen
- Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, P.R. China
| | - Jinning Lou
- Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Chaoyang, Beijing 100029, P.R. China
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Fazio EN, Young CC, Toma J, Levy M, Berger KR, Johnson CL, Mehmood R, Swan P, Chu A, Cregan SP, Dilworth FJ, Howlett CJ, Pin CL. Activating transcription factor 3 promotes loss of the acinar cell phenotype in response to cerulein-induced pancreatitis in mice. Mol Biol Cell 2017; 28:2347-2359. [PMID: 28701342 PMCID: PMC5576899 DOI: 10.1091/mbc.e17-04-0254] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/22/2017] [Accepted: 06/27/2017] [Indexed: 12/20/2022] Open
Abstract
Pancreatitis is a debilitating disease of the exocrine pancreas that, under chronic conditions, is a major susceptibility factor for pancreatic ductal adenocarcinoma (PDAC). Although down-regulation of genes that promote the mature acinar cell fate is required to reduce injury associated with pancreatitis, the factors that promote this repression are unknown. Activating transcription factor 3 (ATF3) is a key mediator of the unfolded protein response, a pathway rapidly activated during pancreatic insult. Using chromatin immunoprecipitation followed by next-generation sequencing, we show that ATF3 is bound to the transcriptional regulatory regions of >30% of differentially expressed genes during the initiation of pancreatitis. Of importance, ATF3-dependent regulation of these genes was observed only upon induction of pancreatitis, with pathways involved in inflammation, acinar cell differentiation, and cell junctions being specifically targeted. Characterizing expression of transcription factors that affect acinar cell differentiation suggested that acinar cells lacking ATF3 maintain a mature cell phenotype during pancreatitis, a finding supported by maintenance of junctional proteins and polarity markers. As a result, Atf3-/- pancreatic tissue displayed increased tissue damage and inflammatory cell infiltration at early time points during injury but, at later time points, showed reduced acinar-to-duct cell metaplasia. Thus our results reveal a critical role for ATF3 as a key regulator of the acinar cell transcriptional response during injury and may provide a link between chronic pancreatitis and PDAC.
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Affiliation(s)
- Elena N Fazio
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Oncology, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Claire C Young
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Jelena Toma
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Michael Levy
- Children's Health Research Institute, London, ON N6C 2V5, Canada
| | - Kurt R Berger
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Charis L Johnson
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Rashid Mehmood
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Patrick Swan
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
- Robarts Research Institute, University of Western Ontario, London, ON N6A 5B7, Canada
| | - Alphonse Chu
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Sean P Cregan
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
- Robarts Research Institute, University of Western Ontario, London, ON N6A 5B7, Canada
| | - F Jeffrey Dilworth
- Department of Pathology and Laboratory Medicine, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Christopher J Howlett
- Department of Pathology and Laboratory Medicine, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Christopher L Pin
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Oncology, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
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Reduced insulin secretion function is associated with pancreatic islet redistribution of cell adhesion molecules (CAMS) in diabetic mice after prolonged high-fat diet. Histochem Cell Biol 2016; 146:13-31. [PMID: 27020567 DOI: 10.1007/s00418-016-1428-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2016] [Indexed: 01/09/2023]
Abstract
Intercellular junctions play a role in regulating islet cytoarchitecture, insulin biosynthesis and secretion. In this study, we investigated the animal metabolic state as well as islet histology and cellular distribution/expression of CAMs and F-actin in the endocrine pancreas of C57BL/6/JUnib mice fed a high-fat diet (HFd) for a prolonged time period (8 months). Mice fed a HFd became obese and type 2 diabetic, displaying significant peripheral insulin resistance, hyperglycemia and moderate hyperinsulinemia. Isolated islets of HFd-fed mice displayed a significant impairment of glucose-induced insulin secretion associated with a diminished frequency of intracellular calcium oscillations compared with control islets. No marked change in islet morphology and cytoarchitecture was observed; however, HFd-fed mice showed higher beta cell relative area in comparison with controls. As shown by immunohistochemistry, ZO-1, E-, N-cadherins, α- and β-catenins were expressed at the intercellular contact site of endocrine cells, while VE-cadherin, as well as ZO-1, was found at islet vascular compartment. Redistribution of N-, E-cadherins and α-catenin (from the contact region to the cytoplasm in endocrine cells) associated with increased submembranous F-actin cell level as well as increased VE-cadherin islet immunolabeling was observed in diabetic mice. Increased gene expression of VE-cadherin and ZO-1, but no change for the other proteins, was observed in islets of diabetic mice. Only in the case of VE-cadherin, a significant increase in islet content of this CAM was detected by immunoblotting in diabetic mice. In conclusion, CAMs are expressed by endocrine and endothelial cells of pancreatic islets. The distribution/expression of N-, E- and VE-cadherins as well as α-catenin and F-actin is significantly altered in islet cells of obese and diabetic mice.
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Marçal-Pessoa AF, Bassi-Branco CL, Salvatierra CDSB, Stoppiglia LF, Ignacio-Souza LM, de Lima Reis SR, Veloso RV, de Barros Reis MA, Carneiro EM, Boschero AC, Arantes VC, Latorraca MQ. A low-protein diet during pregnancy prevents modifications in intercellular communication proteins in rat islets. Biol Res 2015; 48:3. [PMID: 25654754 PMCID: PMC4362834 DOI: 10.1186/0717-6287-48-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 01/07/2015] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Gap junctions between β-cells participate in the precise regulation of insulin secretion. Adherens junctions and their associated proteins are required for the formation, function and structural maintenance of gap junctions. Increases in the number of the gap junctions between β-cells and enhanced glucose-stimulated insulin secretion are observed during pregnancy. In contrast, protein restriction produces structural and functional alterations that result in poor insulin secretion in response to glucose. We investigated whether protein restriction during pregnancy affects the expression of mRNA and proteins involved in gap and adherens junctions in pancreatic islets. An isoenergetic low-protein diet (6% protein) was fed to non-pregnant or pregnant rats from day 1-15 of pregnancy, and rats fed an isocaloric normal-protein diet (17% protein) were used as controls. RESULTS The low-protein diet reduced the levels of connexin 36 and β-catenin protein in pancreatic islets. In rats fed the control diet, pregnancy increased the levels of phospho-[Ser(279/282)]-connexin 43, and it decreased the levels of connexin 36, β-catenin and beta-actin mRNA as well as the levels of connexin 36 and β-catenin protein in islets. The low-protein diet during pregnancy did not alter these mRNA and protein levels, but avoided the increase of levels of phospho-[Ser(279/282)]-connexin 43 in islets. Insulin secretion in response to 8.3 mmol/L glucose was higher in pregnant rats than in non-pregnant rats, independently of the nutritional status. CONCLUSION Short-term protein restriction during pregnancy prevented the Cx43 phosphorylation, but this event did not interfer in the insulin secretion.
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Affiliation(s)
- Ana Flávia Marçal-Pessoa
- Mestrado em Ciências da Saúde, Faculdade de Ciências Médicas, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil.
| | - Carmen Lucia Bassi-Branco
- Departamento de Ciências Básicas em Saúde, Faculdade de Ciências Médicas, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil.
| | | | - Luiz Fabrizio Stoppiglia
- Departamento de Psicologia, Instituto de Educação, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil.
| | - Letícia Martins Ignacio-Souza
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil.
| | - Sílvia Regina de Lima Reis
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil.
| | - Roberto Vilela Veloso
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil.
| | | | - Everardo Magalhães Carneiro
- Departamento de Anatomia, Biologia Celular e Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.
| | - Antonio Carlos Boschero
- Departamento de Anatomia, Biologia Celular e Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.
| | - Vanessa Cristina Arantes
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil.
| | - Márcia Queiroz Latorraca
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil.
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12
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Squires PE, Jones PM, Younis MYG, Hills CE. The calcium-sensing receptor and β-cell function. VITAMINS AND HORMONES 2014; 95:249-67. [PMID: 24559921 DOI: 10.1016/b978-0-12-800174-5.00010-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
In addition to its central role controlling systemic calcium homeostasis, the extracellular calcium-sensing receptor (CaSR) can be found on multiple cell types not associated with controlling plasma calcium. The endocrine pancreas is one such tissue, and it is apparent that the receptor plays an important role in regulating β-cell function. During exocytosis, divalent cations are coreleased with insulin and their concentration within the restricted intercellular compartments of the pancreatic islet increases sufficiently to activate the CaSR on neighboring cells. Acute and chronic activation of the receptor has multiple effects on the β-cell, from increasing cadherin-based cell-cell adhesion to directly altering the expression and function of various potassium and voltage-dependent calcium channels. The promiscuous activation of multiple binding partners improves cell adhesion, cell coupling, and cell-to-cell communication within the islet and is the basis for the effect of the CaSR on β-cell function and improved glucose responsiveness.
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Affiliation(s)
- Paul E Squires
- School of Life Sciences, University of Warwick, Coventry, United Kingdom.
| | - Peter M Jones
- Diabetes & Nutritional Sciences Division, School of Medicine, King's College London, London, United Kingdom
| | - Mustafa Y G Younis
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Claire E Hills
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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13
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Wolden-Kirk H, Overbergh L, Gysemans C, Brusgaard K, Naamane N, Van Lommel L, Schuit F, Eizirik DL, Christesen H, Mathieu C. Unraveling the effects of 1,25OH2D3 on global gene expression in pancreatic islets. J Steroid Biochem Mol Biol 2013; 136:68-79. [PMID: 23137852 DOI: 10.1016/j.jsbmb.2012.10.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 10/19/2012] [Accepted: 10/20/2012] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Vitamin D deficiency has been linked to type 1 and 2 diabetes, whereas supplementation may prevent both diseases. However, the extent of the effects of vitamin D or its metabolites directly on pancreatic islets is still largely unknown. The aim of the present study was to investigate how active vitamin D, 1,25(OH)2D3, affects beta cells directly by establishing its effects on global gene expression in healthy murine islets. MATERIALS AND METHODS Pancreatic islets were isolated from 2 to 3 week old C57BL/6 mice and cultured in vitro with 1,25(OH)2D3 or vehicle for 6 and 24h. Total RNA was extracted from the islets and the effects on global gene expression were analyzed using Affymetrix microarrays. RESULTS AND DISCUSSION Exposure to 1,25(OH)2D3 compared to vehicle resulted in 306 and 151 differentially expressed genes after 6 and 24h, respectively (n=4, >1.3-fold, p<0.02). Of these 220 were up-regulated, whereas 86 displayed a decreased expression after 6h. Furthermore, expression levels were increased for 124 and decreased for 27 genes following 24h of exposure. Formation of intercellular junctions, cytoskeletal organization, and intracellular trafficking as well as lipid metabolism and ion transport were among the most affected gene classes. Effects on several genes already identified as being part of vitamin D signaling in other cell types were observed along with genes known to affect insulin release, although with our assay we were not able to detect any effects of 1,25(OH)2D3 on glucose-stimulated insulin release from healthy pancreatic islets. CONCLUSION The effects of 1,25(OH)2D3 on the expression of cytoskeletal and intracellular trafficking genes along with genes involved in ion transport may influence insulin exocytosis. However, an effect of 1,25(OH)2D3 on insulin release could not be detected for healthy islets in contrast to islets subjected to pathological conditions such as cytokine exposure and vitamin D deficiency as suggested by other studies. Thus, in addition to previously identified tolerogenic effects on the immune system, 1,25(OH)2D3 may affect basic functions of pancreatic beta cells, with the potential to render them more resistant to the detrimental conditions encountered during type 1 and 2 diabetes. This article is part of a Special Issue entitled 'Vitamin D Workshop'.
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Affiliation(s)
- H Wolden-Kirk
- Clinical and Experimental Endocrinology, University Hospital Gasthuisberg, Catholic University of Leuven, Herestraat 49, Box 902, B-3000 Leuven, Belgium.
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14
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Santos-Silva JC, Carvalho CPDF, de Oliveira RB, Boschero AC, Collares-Buzato CB. Cell-to-cell contact dependence and junctional protein content are correlated with in vivo maturation of pancreatic beta cells. Can J Physiol Pharmacol 2012; 90:837-50. [DOI: 10.1139/y2012-064] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In this study, we investigated the cellular distribution of junctional proteins and the dependence on cell–cell contacts of pancreatic beta cells during animal development. Fetus and newborn rat islets, which display a relatively poor insulin secretory response to glucose, present an immature morphology and cytoarchitecture when compared with young and adult islets that are responsive to glucose. At the perinatal stage, beta cells display a low junctional content of neural cell adhesion molecule (N-CAM), α- and β-catenins, ZO-1, and F-actin, while a differential distribution of N-CAM and Pan-cadherin was seen in beta cells and nonbeta cells only from young and adult islets. In the absence of intercellular contacts, the glucose-stimulated insulin secretion was completely blocked in adult beta cells, but after reaggregation they partially reestablished the secretory response to glucose. By contrast, neonatal beta cells were poorly responsive to sugar, regardless of whether they were arranged as intact islets or as isolated cells. Interestingly, after 10 days of culturing, neonatal beta cells, known to display increased junctional protein content in vitro, became responsive to glucose and concomitantly dependent on cell–cell contacts. Therefore, our data suggest that the developmental acquisition of an adult-like insulin secretory pattern is paralleled by a dependence on direct cell–cell interactions.
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Affiliation(s)
- Junia Carolina Santos-Silva
- Department of Histology and Embryology, Institute of Biology, University of Campinas (UNICAMP), Campinas CEP 13083-970, São Paulo, Brazil
| | - Carolina Prado de França Carvalho
- Department of Histology and Embryology, Institute of Biology, University of Campinas (UNICAMP), Campinas CEP 13083-970, São Paulo, Brazil
| | - Ricardo Beltrame de Oliveira
- Department of Histology and Embryology, Institute of Biology, University of Campinas (UNICAMP), Campinas CEP 13083-970, São Paulo, Brazil
| | - Antonio Carlos Boschero
- Department of Anatomy, Cell Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Carla Beatriz Collares-Buzato
- Department of Histology and Embryology, Institute of Biology, University of Campinas (UNICAMP), Campinas CEP 13083-970, São Paulo, Brazil
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15
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Vargas N, Álvarez-Cubela S, Giraldo JA, Nieto M, Fort NM, Cechin S, García E, Espino-Grosso P, Fraker CA, Ricordi C, Inverardi L, Pastori RL, Domínguez-Bendala J. TAT-mediated transduction of MafA protein in utero results in enhanced pancreatic insulin expression and changes in islet morphology. PLoS One 2011; 6:e22364. [PMID: 21857924 PMCID: PMC3150355 DOI: 10.1371/journal.pone.0022364] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 06/24/2011] [Indexed: 01/01/2023] Open
Abstract
Alongside Pdx1 and Beta2/NeuroD, the transcription factor MafA has been shown to be instrumental in the maintenance of the beta cell phenotype. Indeed, a combination of MafA, Pdx1 and Ngn3 (an upstream regulator of Beta2/NeuroD) was recently reported to lead to the effective reprogramming of acinar cells into insulin-producing beta cells. These experiments set the stage for the development of new strategies to address the impairment of glycemic control in diabetic patients. However, the clinical applicability of reprogramming in this context is deemed to be poor due to the need to use viral vehicles for the delivery of the above factors. Here we describe a recombinant transducible version of the MafA protein (TAT-MafA) that penetrates across cell membranes with an efficiency of 100% and binds to the insulin promoter in vitro. When injected in utero into living mouse embryos, TAT-MafA significantly up-regulates target genes and induces enhanced insulin production as well as cytoarchitectural changes consistent with faster islet maturation. As the latest addition to our armamentarium of transducible proteins (which already includes Pdx1 and Ngn3), the purification and characterization of a functional TAT-MafA protein opens the door to prospective therapeutic uses that circumvent the use of viral delivery. To our knowledge, this is also the first report on the use of protein transduction in utero.
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MESH Headings
- Animals
- Animals, Newborn
- Blotting, Western
- Cell Line, Tumor
- Cells, Cultured
- Female
- Gene Expression
- Gene Products, tat/genetics
- Gene Products, tat/metabolism
- Insulin/genetics
- Insulin/metabolism
- Islets of Langerhans/cytology
- Islets of Langerhans/metabolism
- Maf Transcription Factors, Large/genetics
- Maf Transcription Factors, Large/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Pancreas/embryology
- Pancreas/metabolism
- Pregnancy
- Promoter Regions, Genetic/genetics
- Protein Binding
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Transfection
- Uterus/metabolism
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Affiliation(s)
- Nancy Vargas
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Silvia Álvarez-Cubela
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Jaime A. Giraldo
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Department of Biomedical Engineering, University of Miami, Miami, Florida, United States of America
| | - Margarita Nieto
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Nicholas M. Fort
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Sirlene Cechin
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Enrique García
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Pedro Espino-Grosso
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Christopher A. Fraker
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Department of Biomedical Engineering, University of Miami, Miami, Florida, United States of America
| | - Camillo Ricordi
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Department of Surgery, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Luca Inverardi
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Ricardo L. Pastori
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Juan Domínguez-Bendala
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Department of Surgery, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
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16
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Epithelial cell–cell junctions and plasma membrane domains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:820-31. [DOI: 10.1016/j.bbamem.2008.07.015] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 07/10/2008] [Accepted: 07/21/2008] [Indexed: 12/16/2022]
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17
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Bhoj EJ, Romeo S, Baroni MG, Bartov G, Schultz RA, Zinn AR. MODY-like diabetes associated with an apparently balanced translocation: possible involvement of MPP7 gene and cell polarity in the pathogenesis of diabetes. Mol Cytogenet 2009; 2:5. [PMID: 19216786 PMCID: PMC2646739 DOI: 10.1186/1755-8166-2-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Accepted: 02/13/2009] [Indexed: 11/10/2022] Open
Abstract
Background Characterization of disease-associated balanced translocations has led to the discovery of genes responsible for many disorders, including syndromes that include various forms of diabetes mellitus. We studied a man with unexplained maturity onset diabetes of the young (MODY)-like diabetes and an apparently balanced translocation [46,XY,t(7;10)(q22;p12)] and sought to identify a novel diabetes locus by characterizing the translocation breakpoints. Results Mutations in coding exons and splice sites of known MODY genes were first ruled out by PCR amplification and DNA sequencing. Fluorescent in situ hybridization (FISH) studies demonstrated that the translocation did not disrupt two known diabetes-related genes on 10p12. The translocation breakpoints were further mapped to high resolution using FISH and somatic cell hybrids and the junctions PCR-amplified and sequenced. The translocation did not disrupt any annotated transcription unit. However, the chromosome 10 breakpoint was 220 kilobases 5' to the Membrane Protein, Palmitoylated 7 (MPP7) gene, which encodes a protein required for proper cell polarity. This biological function is shared by HNF4A, a known MODY gene. Databases show MPP7 is highly expressed in mouse pancreas and is expressed in human islets. The translocation did not appear to alter lymphoblastoid expression of MPP7 or other genes near the breakpoints. Conclusion The balanced translocation and MODY-like diabetes in the proband could be coincidental. Alternatively, the translocation may cause islet cell dysfunction by altering MPP7 expression in a subtle or tissue-specific fashion. The potential roles of MPP7 mutations in diabetes and perturbed islet cell polarity in insulin secretion warrant further study.
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Affiliation(s)
- Elizabeth J Bhoj
- McDermott Center for Human Growth and Development, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
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18
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Rogers GJ, Hodgkin MN, Squires PE. E-cadherin and cell adhesion: a role in architecture and function in the pancreatic islet. Cell Physiol Biochem 2007; 20:987-94. [PMID: 17982281 DOI: 10.1159/000110459] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The efficient secretion of insulin from beta-cells requires extensive intra-islet communication. The cell surface adhesion protein epithelial (E)-cadherin (ECAD) establishes and maintains epithelial tissues such as the islets of Langerhans. In this study, the role of ECAD in regulating insulin secretion from pseudoislets was investigated. METHODS The effect of an immuno-neutralising ECAD on gross morphology, cytosolic calcium signalling, direct cell-to-cell communication and insulin secretion was assessed by fura-2 microfluorimetry, Lucifer Yellow dye injection and insulin ELISA in an insulin-secreting model system. RESULTS Antibody blockade of ECAD reduces glucose-evoked changes in [Ca(2+)](i) and insulin secretion. Neutralisation of ECAD causes a breakdown in the glucose-stimulated synchronicity of calcium oscillations between discrete regions within the pseudoislet, and the transfer of dye from an individual cell within a cell cluster is attenuated in the absence of ECAD ligation, demonstrating that gap junction communication is disrupted. The functional consequence of neutralising ECAD is a significant reduction in insulin secretion. CONCLUSION Cell adhesion via ECAD has distinct roles in the regulation of intercellular communication between beta-cells within islets, with potential repercussions for insulin secretion.
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Affiliation(s)
- Gareth J Rogers
- Molecular Physiology Group, Biomedical Research Institute, Department of Biological Sciences, University of Warwick Coventry, UK
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19
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Borka K, Kaliszky P, Szabó E, Lotz G, Kupcsulik P, Schaff Z, Kiss A. Claudin expression in pancreatic endocrine tumors as compared with ductal adenocarcinomas. Virchows Arch 2007; 450:549-57. [PMID: 17429687 DOI: 10.1007/s00428-007-0406-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Revised: 03/12/2007] [Accepted: 03/13/2007] [Indexed: 12/17/2022]
Abstract
Altered expression of recently described claudins (CLDNs) as members of tight junction (TJ) transmembrane proteins was noted in several malignancies. We aimed to analyze protein and messenger RNA (mRNA) expressions of different CLDNs in human pancreatic endocrine tumors (PET) and ductal adenocarcinomas. A total of 45 formalin-fixed, paraffin-embedded samples were studied. Immunohistochemistry and real-time reverse transcriptase polymerase chain reaction analysis were carried out for quantification of CLDN 1, -2, -3, -4, and -7 expressions. Normal acini and ducts showed strong CLDNs 1, -3, -4, and -7 and scattered CLDN 2 protein expressions, while Langerhans islands revealed only CLDN 3 and -7 expressions. CLDN 2 expression was found in the half of ductal adenocarcinomas, while the vast majority of endocrine tumors were negative. CLDN 1, -4, and -7 immunohistochemistry was positive in all adenocarcinomas, whereas endocrine tumors were completely negative for CLDNs 1 and -4. CLDN 3 and -7 proteins were detected in all endocrine tumors, while CLDN 3 in ductal adenocarcinomas was negative. The mRNA expression of CLDNs showed differences between endocrine tumors and ductal adenocarcinomas, similar as found for protein expression. Our findings support that PET and ductal carcinomas are specifically characterized by different expression pattern of CLDNs. High expressions of CLDN 3 in endocrine tumors and CLDN 4 in ductal carcinomas might attract them as targets for adjuvant therapy.
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MESH Headings
- Adenoma, Islet Cell/genetics
- Adenoma, Islet Cell/metabolism
- Adenoma, Islet Cell/pathology
- Adult
- Aged
- Aged, 80 and over
- Biomarkers, Tumor
- Carcinoma, Islet Cell/genetics
- Carcinoma, Islet Cell/metabolism
- Carcinoma, Islet Cell/pathology
- Carcinoma, Pancreatic Ductal/genetics
- Carcinoma, Pancreatic Ductal/metabolism
- Carcinoma, Pancreatic Ductal/secondary
- Female
- Gene Expression
- Humans
- Immunoenzyme Techniques
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Middle Aged
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/metabolism
- Pancreatic Neoplasms/pathology
- RNA, Messenger/metabolism
- Retrospective Studies
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Katalin Borka
- 2nd Department of Pathology, Semmelweis University, Ulloi út 93, 1091, Budapest, Hungary
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20
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Hodgkin MN, Rogers GJ, Squires PE. Colocalization between beta-catenin and insulin suggests a novel role for the adherens junction in beta-cell function. Pancreas 2007; 34:170-1. [PMID: 17198206 DOI: 10.1097/01.mpa.0000240616.28098.55] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
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21
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Rinta-Valkama J, Palmén T, Lassila M, Holthöfer H. Podocyte-associated proteins FAT, alpha-actinin-4 and filtrin are expressed in Langerhans islets of the pancreas. Mol Cell Biochem 2006; 294:117-25. [PMID: 16841182 DOI: 10.1007/s11010-006-9251-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Accepted: 06/01/2006] [Indexed: 02/02/2023]
Abstract
Nephrin is a crucial podocyte molecule in the kidney glomerular filtration barrier and it is also expressed in Langerhans islet beta cells of the pancreas. Recently, genetic mapping of proteinuric kidney disease genes and animal models have revealed further important molecules for the kidney filtration function including alpha-actinin-4, podocin, FAT, and NEPH1. This study was addressed to explore the pancreatic expression of the podocyte molecules podocin, FAT, alpha-actinin-4, NEPH1, NEPH2, filtrin/NEPH3, synaptopodin and CD2 associated protein (CD2AP). The mRNA and protein expressions were studied by RT-PCR and immunoblotting, and localization in the pancreas was investigated by immunofluorescence. Of the nephrin-associated podocyte proteins, filtrin/NEPH3, FAT, and alpha-actinin-4 were found to be expressed in the pancreas at the gene and protein level and localized to Langerhans islets. Immunoreactivity with the podocin antibody was detected mostly in the exocrine pancreas. NEPH1 and synaptopodin expression was detected only at the mRNA level. Further studies are needed to unravel the functional role of these podocyte-associated molecules in the pancreatic Langerhans islets.
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Affiliation(s)
- Johanna Rinta-Valkama
- Research Program in Molecular Medicine, Biomedicum Helsinki, Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, PB 63, 00014, Helsinki, Finland
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22
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Leite AR, Carvalho CPF, Furtado AG, Barbosa HCL, Boschero AC, Collares-Buzato CB. Co-expression and regulation of connexins 36 and 43 in cultured neonatal rat pancreatic islets. Can J Physiol Pharmacol 2005; 83:142-51. [PMID: 15791287 DOI: 10.1139/y04-133] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fetal and neonatal pancreatic islets present a lower insulin secretory response as compared with adult islets. Prolonged culturing leads to an improvement of the glucose-induced insulin secretion response in neonatal pancreatic islets that may involve regulation of gap junction mediated cell communication. In this study, we investigated the effect of culturing neonatal islet cells for varying periods of time and with different glucose medium concentrations on the cellular expression of the endocrine pancreatic gap junction associated connexin (Cx) 36 and Cx43. We report here that the 7-d culture induced upregulation of the expression of these junctional proteins in neonatal islets in a time-dependent manner. A correlation was observed between the increased mRNA and protein expression of Cx36 and Cx43 and the increased insulin secretion following islet culturing. In addition, increasing glucose concentration within the culture medium induced a concentration-dependent enhancement of Cx36 islet expression, but not of Cx43 expression in cultured neonatal islets. In conclusion, we suggest that the regulation of gap junctional proteins by culture medium containing factors and glucose may be an important event for the maturation process of beta cells observed at in vitro conditions.
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Affiliation(s)
- A R Leite
- Department of Physiology and Biophysics, Universidade Estadual de Campinas, Brasil
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