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Chen X, Xie X, Li J, Sun L, Lv Z, Yao X, Li L, Jin H, Cui S, Liu J. BCAS2 Participates in Insulin Synthesis and Secretion via mRNA Alternative Splicing in Mice. Endocrinology 2023; 165:bqad152. [PMID: 37820033 DOI: 10.1210/endocr/bqad152] [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: 07/02/2023] [Revised: 09/22/2023] [Accepted: 10/09/2023] [Indexed: 10/13/2023]
Abstract
Insulin secreted by pancreatic β cells is essential for maintaining blood glucose levels. Diabetes is caused primarily by a loss of β cells or impairment of β-cell function. A previous whole-transcriptome analysis of islets from a type 2 diabetes group and a control group showed that a splicing disorder occurred in approximately 25% of splicing events. Breast carcinoma amplified sequence 2 (BCAS2) is a spliceosome component whose function in islet β cells is unclear. Here, we report that knockdown of Bcas2 decreased glucose- and KCl-stimulated insulin secretion in the NIT-1 cell line. Pancreas weight, glucose tolerance, and insulin sensitivity were measured in normal chow-fed Bcas2 f/f-βKO mice, and β-cell mass and islet size were analyzed by immunohistochemistry. Glucose intolerance developed in Bcas2 f/f-βKO mice, but there were no significant differences in pancreas weight, insulin sensitivity, β-cell mass, or islet size. Furthermore, observation of glucose-stimulated insulin secretion and insulin secretion granules in normal chow-fed mice revealed that the insulin level in serum and the number of insulin secretion granules were decreased in Bcas2 f/f-βKO mice. These differences were related to abnormal splicing of Syt7 and Tcf7l2 pre-mRNA. Taken together, these results demonstrate that BCAS2 is involved in alternative splicing during insulin synthesis and secretion.
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Affiliation(s)
- Xuexue Chen
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xiaomei Xie
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jianhua Li
- Reproductive Medical Center, Department of Obstetrics and Gynecology, the Seventh Medical Center of PLA General Hospital, Beijing 100007, China
| | - Longjie Sun
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zheng Lv
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xiaohong Yao
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Lei Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hua Jin
- Department of Pathology, the Seventh Medical Center of PLA General Hospital, Beijing 100007, China
| | - Sheng Cui
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Jiali Liu
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing 100193, China
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Li J, Peng H, Ji W, Lu D, Wang N, Peng C, Zhang W, Li M, Li Y. Advances in surface-modified nanometal-organic frameworks for drug delivery. Int J Pharm 2023:123119. [PMID: 37302666 DOI: 10.1016/j.ijpharm.2023.123119] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/13/2023]
Abstract
Nanometal-organic frameworks (NMOFs) are porous network structures composed of metal ions or metal clusters through self-assembly. NMOFs have been considered as a promising nano-drug delivery system due to their unique properties such as pore and flexible structures, large specific surface areas, surface modifiability, non-toxic and degradable properties. However, NMOFs face a series complex environment during in vivo delivery. Therefore, surface functionalization of NMOFs is vital to ensure that the structure of NMOFs remain stable during delivery, and can overcome physiological barriers to deliver drugs more accurately to specific sites, and achieve controllable release. In this review, the first part summarizes the physiological barriers that NMOFs faced during drug delivery after intravenous injection and oral administration. The second part summarizes the current main ways to load drugs into NMOFs, mainly including pore adsorption, surface attachment, formation of covalent/coordination bonds between drug molecules and NMOFs, and in situ encapsulation. The third part is the main review part of this paper, which summarizes the surface modification methods of NMOFs used in recent years to overcome the physiological barriers and achieve effective drug delivery and disease therapy, which are mainly divided into physical modifications and chemical modifications. Finally, the full text is summarized and prospected, with the hope to provide ideas for the future development of NMOFs as drug delivery.
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Affiliation(s)
- Jiaxin Li
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Huan Peng
- Protein Science Key Laboratory of the Ministry of Education, School of Pharmaceutical Sciences, Tsinghua University, Beijing, 100084, China
| | - Weihong Ji
- Institute of Biomaterials and Tissue Engineering, Fujian Provincial Key Laboratory of Biochemical Technology, Huaqiao University, Xiamen, 361021, China
| | - Dengyang Lu
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Nan Wang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Chen Peng
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Wen Zhang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Muzi Li
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yan Li
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
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Zhang R, Zhang Y, Liu T, Jiang B, Li Z, Qu Y, Chen Y, Li Z. Utilizing Variants Identified with Multiple Genome-Wide Association Study Methods Optimizes Genomic Selection for Growth Traits in Pigs. Animals (Basel) 2023; 13:ani13040722. [PMID: 36830509 PMCID: PMC9952664 DOI: 10.3390/ani13040722] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 02/09/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
Improving the prediction accuracies of economically important traits in genomic selection (GS) is a main objective for researchers and breeders in the livestock industry. This study aims at utilizing potentially functional SNPs and QTLs identified with various genome-wide association study (GWAS) models in GS of pig growth traits. We used three well-established GWAS methods, including the mixed linear model, Bayesian model and meta-analysis, as well as 60K SNP-chip and whole genome sequence (WGS) data from 1734 Yorkshire and 1123 Landrace pigs to detect SNPs related to four growth traits: average daily gain, backfat thickness, body weight and birth weight. A total of 1485 significant loci and 24 candidate genes which are involved in skeletal muscle development, fatty deposition, lipid metabolism and insulin resistance were identified. Compared with using all SNP-chip data, GS with the pre-selected functional SNPs in the standard genomic best linear unbiased prediction (GBLUP), and a two-kernel based GBLUP model yielded average gains in accuracy by 4 to 46% (from 0.19 ± 0.07 to 0.56 ± 0.07) and 5 to 27% (from 0.16 ± 0.06 to 0.57 ± 0.05) for the four traits, respectively, suggesting that the prioritization of preselected functional markers in GS models had the potential to improve prediction accuracies for certain traits in livestock breeding.
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Affiliation(s)
- Ruifeng Zhang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Yi Zhang
- Institute of Neuroscience, Panzhihua University, Panzhihua 617000, China
| | - Tongni Liu
- Genetic Data Center, Faculty of Forestry, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Bo Jiang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Zhenyang Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Youping Qu
- Guangdong IPIG Technology Co., Ltd., Guangzhou 510006, China
| | - Yaosheng Chen
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Zhengcao Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China
- Correspondence:
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Yip L, Alkhataybeh R, Taylor C, Fuhlbrigge R, Fathman CG. Identification of Novel Disease-Relevant Genes and Pathways in the Pathogenesis of Type 1 Diabetes: A Potential Defect in Pancreatic Iron Homeostasis. Diabetes 2022; 71:1490-1507. [PMID: 35499603 PMCID: PMC9233262 DOI: 10.2337/db21-0948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 04/06/2022] [Indexed: 11/13/2022]
Abstract
Multiple pathways contribute to the pathophysiological development of type 1 diabetes (T1D); however, the exact mechanisms involved are unclear. We performed differential gene expression analysis in pancreatic islets of NOD mice versus age-matched congenic NOD.B10 controls to identify genes that may contribute to disease pathogenesis. Novel genes related to extracellular matrix development and glucagon and insulin signaling/secretion were changed in NOD mice during early inflammation. During "respective" insulitis, the expression of genes encoding multiple chemosensory olfactory receptors were upregulated, and during "destructive" insulitis, the expression of genes involved in antimicrobial defense and iron homeostasis were downregulated. Islet inflammation reduced the expression of Hamp that encodes hepcidin. Hepcidin is expressed in β-cells and serves as the key regulator of iron homeostasis. We showed that Hamp and hepcidin levels were lower, while iron levels were higher in the pancreas of 12-week-old NOD versus NOD.B10 mice, suggesting that a loss of iron homeostasis may occur in the islets during the onset of "destructive" insulitis. Interestingly, we showed that the severity of NOD disease correlates with dietary iron intake. NOD mice maintained on low-iron diets had a lower incidence of hyperglycemia, while those maintained on high-iron diets had an earlier onset and higher incidence of disease, suggesting that high iron exposure combined with a loss of pancreatic iron homeostasis may exacerbate NOD disease. This mechanism may explain the link seen between high iron exposure and the increased risk for T1D in humans.
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Batista TM, Garcia-Martin R, Cai W, Konishi M, O'Neill BT, Sakaguchi M, Kim JH, Jung DY, Kim JK, Kahn CR. Multi-dimensional Transcriptional Remodeling by Physiological Insulin In Vivo. Cell Rep 2020; 26:3429-3443.e3. [PMID: 30893613 DOI: 10.1016/j.celrep.2019.02.081] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 01/11/2019] [Accepted: 02/21/2019] [Indexed: 12/12/2022] Open
Abstract
Regulation of gene expression is an important aspect of insulin action but in vivo is intertwined with changing levels of glucose and counter-regulatory hormones. Here we demonstrate that under euglycemic clamp conditions, physiological levels of insulin regulate interrelated networks of more than 1,000 transcripts in muscle and liver. These include expected pathways related to glucose and lipid utilization, mitochondrial function, and autophagy, as well as unexpected pathways, such as chromatin remodeling, mRNA splicing, and Notch signaling. These acutely regulated pathways extend beyond those dysregulated in mice with chronic insulin deficiency or insulin resistance and involve a broad network of transcription factors. More than 150 non-coding RNAs were regulated by insulin, many of which also responded to fasting and refeeding. Pathway analysis and RNAi knockdown revealed a role for lncRNA Gm15441 in regulating fatty acid oxidation in hepatocytes. Altogether, these changes in coding and non-coding RNAs provide an integrated transcriptional network underlying the complexity of insulin action.
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Affiliation(s)
- Thiago M Batista
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Ruben Garcia-Martin
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Weikang Cai
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Masahiro Konishi
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Brian T O'Neill
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA; Division of Endocrinology and Metabolism, Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Masaji Sakaguchi
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA; Department of Metabolic Medicine, Kumamoto University, 1-1-1 Honjo, Chuoku, Kumamoto 860-8556, Japan
| | - Jong Hun Kim
- Program in Molecular Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Food Science and Biotechnology, Sungshin University, Seoul 01133, Republic of Korea
| | - Dae Young Jung
- Program in Molecular Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jason K Kim
- Program in Molecular Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA; Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - C Ronald Kahn
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA.
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Yip L, Fuhlbrigge R, Alkhataybeh R, Fathman CG. Gene Expression Analysis of the Pre-Diabetic Pancreas to Identify Pathogenic Mechanisms and Biomarkers of Type 1 Diabetes. Front Endocrinol (Lausanne) 2020; 11:609271. [PMID: 33424774 PMCID: PMC7793767 DOI: 10.3389/fendo.2020.609271] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 11/16/2020] [Indexed: 12/28/2022] Open
Abstract
Type 1 Diabetes (T1D) occurs as a result of the autoimmune destruction of pancreatic β-cells by self-reactive T cells. The etiology of this disease is complex and difficult to study due to a lack of disease-relevant tissues from pre-diabetic individuals. In this study, we performed gene expression analysis on human pancreas tissues obtained from the Network of Pancreatic Organ Donors with Diabetes (nPOD), and showed that 155 genes were differentially expressed by ≥2-fold in the pancreata of autoantibody-positive (AA+) at-risk individuals compared to healthy controls. Only 48 of these genes remained changed by ≥2-fold in the pancreata of established T1D patients. Pathway analysis of these genes showed a significant association with various immune pathways. We were able to validate the differential expression of eight disease-relevant genes by QPCR analysis: A significant upregulation of CADM2, and downregulation of TRPM5, CRH, PDK4, ANGPL4, CLEC4D, RSG16, and FCGR2B was confirmed in the pancreata of AA+ individuals versus controls. Studies have already implicated FCGR2B in the pathogenesis of disease in non-obese diabetic (NOD) mice. Here we showed that CADM2, TRPM5, PDK4, and ANGPL4 were similarly changed in the pancreata of pre-diabetic 12-week-old NOD mice compared to NOD.B10 controls, suggesting a possible role for these genes in the pathogenesis of both T1D and NOD disease. The loss of the leukocyte-specific gene, FCGR2B, in the pancreata of AA+ individuals, is particularly interesting, as it may serve as a potential whole blood biomarker of disease progression. To test this, we quantified FCGR2B expression in peripheral blood samples of T1D patients, and AA+ and AA- first-degree relatives of T1D patients enrolled in the TrialNet Pathway to Prevention study. We showed that FCGR2B was significantly reduced in the peripheral blood of AA+ individuals compared to AA- controls. Together, these findings demonstrate that gene expression analysis of pancreatic tissue and peripheral blood samples can be used to identify disease-relevant genes and pathways and potential biomarkers of disease progression in T1D.
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Dotta F, Ventriglia G, Snowhite IV, Pugliese A. MicroRNAs: markers of β-cell stress and autoimmunity. Curr Opin Endocrinol Diabetes Obes 2018; 25:237-245. [PMID: 29846238 DOI: 10.1097/med.0000000000000420] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW We discuss current knowledge about microRNAs (miRNAs) in type 1 diabetes (T1D), an autoimmune disease leading to severe loss of pancreatic β-cells. We describe: the role of cellular miRNAs in regulating immune functions and pathways impacting insulin secretion and β-cell survival; circulating miRNAs as disease biomarkers. RECENT FINDINGS Studies examined miRNAs in experimental models and patients, including analysis of tissues from organ donors, peripheral blood cells, and circulating miRNAs in serum, plasma, and exosomes. Studies employed diverse designs and methodologies to detect miRNAs and measure their levels. Selected miRNAs have been linked to the regulation of key biological pathways and disease pathogenesis; several circulating miRNAs are associated with having T1D, islet autoimmunity, disease progression, and immune and metabolic functions, for example, C-peptide secretion, in multiple studies. SUMMARY A growing literature reveals multiple roles of miRNAs in T1D, provide new clues into the regulation of disease mechanisms, and identify reproducible associations. Yet challenges remain, and the field will benefit from joint efforts to analyze results, compare methodologies, formally test the robustness of miRNA associations, and ultimately move towards validating robust miRNA biomarkers.
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Affiliation(s)
- Francesco Dotta
- Diabetes Unit, Department of Medicine, Surgery and Neuroscience, University of Siena
- Fondazione Umberto di Mario, Toscana Life Sciences, Siena, Italy
| | - Giuliana Ventriglia
- Diabetes Unit, Department of Medicine, Surgery and Neuroscience, University of Siena
- Fondazione Umberto di Mario, Toscana Life Sciences, Siena, Italy
| | | | - Alberto Pugliese
- Diabetes Research Institute
- Department of Medicine, Division of Endocrinology and Metabolism
- Department of Microbiology and Immunology, Leonard Miller School of Medicine, University of Miami, Miami, Florida, USA
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Varani K, Vincenzi F, Merighi S, Gessi S, Borea PA. Biochemical and Pharmacological Role of A1 Adenosine Receptors and Their Modulation as Novel Therapeutic Strategy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1051:193-232. [DOI: 10.1007/5584_2017_61] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Abstract
In 1974, the discovery of a mouse and a rat that spontaneously developed hyperglycemia led to the development of 2 autoimmune diabetes models: nonobese diabetic (NOD) mouse and Bio-Breeding rat. These models have contributed to our understanding of autoimmune diabetes, provided tools to dissect autoimmune islet damage, and facilitated development of early detection, prevention, and treatment of type 1 diabetes. The genetic characterization, monoclonal antibodies, and congenic strains have made NOD mice especially useful.Although the establishment of the inbred NOD mouse strain was documented by Makino et al (Jikken Dobutsu. 1980;29:1-13), this review will focus on the not-as-well-known history leading to the discovery of a glycosuric female mouse by Yoshihiro Tochino. This discovery was spearheaded by years of effort by Japanese scientists from different disciplines and dedicated animal care personnel and by the support of the Shionogi Pharmaceutical Company, Osaka, Japan. The history is based on the early literature, mostly written in Japanese, and personal communications especially with Dr Tochino, who was involved in diabetes animal model development and who contributed to the release of NOD mice to the international scientific community. This article also reviews the scientific contributions made by the Bio-Breeding rat to autoimmune diabetes.
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Briet C, Bourdenet G, Rogner UC, Becourt C, Tardivel I, Drouot L, Arnoult C, do Rego JC, Prevot N, Massaad C, Boyer O, Boitard C. The Spontaneous Autoimmune Neuromyopathy in ICOSL -/- NOD Mice Is CD4 + T-Cell and Interferon-γ Dependent. Front Immunol 2017; 8:287. [PMID: 28424681 PMCID: PMC5371727 DOI: 10.3389/fimmu.2017.00287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/28/2017] [Indexed: 01/07/2023] Open
Abstract
Abrogation of ICOS/ICOS ligand (ICOSL) costimulation prevents the onset of diabetes in the non-obese diabetic (NOD) mouse but, remarkably, yields to the development of a spontaneous autoimmune neuromyopathy. At the pathological level, ICOSL−/− NOD mice show stronger protection from insulitis than their ICOS−/− counterparts. Also, the ICOSL−/− NOD model carries a limited C57BL/6 region containing the Icosl nul mutation, but, in contrast to ICOS−/− NOD mice, no gene variant previously reported as associated to NOD diabetes. Therefore, we aimed at providing a detailed characterization of the ICOSL−/− NOD model. The phenotype observed in ICOSL−/− NOD mice is globally similar to that observed in ICOS−/− and ICOS−/−ICOSL−/− double-knockout NOD mice, manifested by a progressive locomotor disability first affecting the front paws as observed by catwalk analysis and a decrease in grip test performance. The pathology remains limited to peripheral nerve and striated muscle. The muscle disease is characterized by myofiber necrosis/regeneration and an inflammatory infiltrate composed of CD4+ T-cells, CD8+ T-cells, and myeloid cells, resembling human myositis. Autoimmune neuromyopathy can be transferred to NOD.scid recipients by CD4+ but not by CD8+ T-cells isolated from 40-week-old female ICOSL−/− NOD mice. The predominant role of CD4+ T-cells is further demonstrated by the observation that neuromyopathy does not develop in CIITA−/−ICOSL−/− NOD in contrast to β2microglobulin−/−ICOSL−/− NOD mice. Also, the cytokine profile of CD4+ T-cells infiltrating muscle and nerve of ICOSL−/− NOD mice is biased toward a Th1 pattern. Finally, adoptive transfer experiments show that diabetes development requires expression of ICOSL, in contrast to neuromyopathy. Altogether, the deviation of autoimmunity from the pancreas to skeletal muscles in the absence of ICOS/ICOSL signaling in NOD mice is strictly dependent on CD4+ T-cells, leads to myofiber necrosis and regeneration. It provides the first mouse model of spontaneous autoimmune myopathy akin to human myositis.
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Affiliation(s)
- Claire Briet
- INSERM U1016, Cochin Institute, Paris Descartes University, Sorbonne Paris Cité, Paris, France
| | - Gwladys Bourdenet
- Normandie Université, UNIROUEN, INSERM, U1234, Rouen University Hospital, Department of Immunology, Rouen, France
| | | | | | | | - Laurent Drouot
- Normandie Université, UNIROUEN, INSERM, U1234, Rouen University Hospital, Department of Immunology, Rouen, France
| | | | | | - Nicolas Prevot
- Developmental Immunology, Department of Paediatrics, and the Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | | | - Olivier Boyer
- Normandie Université, UNIROUEN, INSERM, U1234, Rouen University Hospital, Department of Immunology, Rouen, France
| | - Christian Boitard
- INSERM U1016, Cochin Institute, Paris Descartes University, Sorbonne Paris Cité, Paris, France
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Thayer TC, Pearson JA, De Leenheer E, Hanna SJ, Boldison J, Davies J, Tsui A, Ahmed S, Easton P, Siew LK, Wen L, Wong FS. Peripheral Proinsulin Expression Controls Low-Avidity Proinsulin-Reactive CD8 T Cells in Type 1 Diabetes. Diabetes 2016; 65:3429-3439. [PMID: 27495224 DOI: 10.2337/db15-1649] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 07/26/2016] [Indexed: 11/13/2022]
Abstract
Low-avidity autoreactive CD8 T cells (CTLs) escape from thymic negative selection, and peripheral tolerance mechanisms are essential for their regulation. We report the role of proinsulin (PI) expression on the development and activation of insulin-specific CTLs in the NOD mouse model of type 1 diabetes. We studied insulin B-chain-specific CTL from different T-cell receptor transgenic mice (G9Cα-/-) expressing normal PI1 and PI2 or altered PI expression levels. In the absence of PI2 (Ins2-/-), CTL in pancreatic lymph nodes (PLNs) were more activated, and male G9Cα-/- mice developed T1D. Furthermore, when the insulin-specific CTLs developed in transgenic mice lacking their specific PI epitope, the CTLs demonstrated increased cytotoxicity and proliferation in vitro and in vivo in the PLNs after adoptive transfer into NOD recipients. Dendritic cell-stimulated proliferation of insulin-specific T cells was reduced in the presence of lymph node stromal cells (LNSCs) from NOD mice but not from mice lacking the PI epitope. Our study shows that LNSCs regulate CTL activation and suggests that exposure to PI in the periphery is very important in maintenance of tolerance of autoreactive T cells. This is relevant for human type 1 diabetes and has implications for the use of antigen-specific therapy in tolerance induction.
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Affiliation(s)
- Terri C Thayer
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K
| | - James A Pearson
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K
| | - Evy De Leenheer
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K
| | - Stephanie J Hanna
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K
| | - Joanne Boldison
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K
| | - Joanne Davies
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K
| | - Adrian Tsui
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K
| | - Sartaj Ahmed
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K
| | - Peter Easton
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K
| | - Lai Khai Siew
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K
| | - Li Wen
- Section of Endocrinology, Yale School of Medicine, New Haven, CT
| | - F Susan Wong
- Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
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Juan-Mateu J, Villate O, Eizirik DL. MECHANISMS IN ENDOCRINOLOGY: Alternative splicing: the new frontier in diabetes research. Eur J Endocrinol 2016; 174:R225-38. [PMID: 26628584 PMCID: PMC5331159 DOI: 10.1530/eje-15-0916] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/01/2015] [Indexed: 12/30/2022]
Abstract
Type 1 diabetes (T1D) is a chronic autoimmune disease in which pancreatic β cells are killed by infiltrating immune cells and by cytokines released by these cells. This takes place in the context of a dysregulated dialogue between invading immune cells and target β cells, but the intracellular signals that decide β cell fate remain to be clarified. Alternative splicing (AS) is a complex post-transcriptional regulatory mechanism affecting gene expression. It regulates the inclusion/exclusion of exons into mature mRNAs, allowing individual genes to produce multiple protein isoforms that expand the proteome diversity. Functionally related transcript populations are co-ordinately spliced by master splicing factors, defining regulatory networks that allow cells to rapidly adapt their transcriptome in response to intra and extracellular cues. There is a growing interest in the role of AS in autoimmune diseases, but little is known regarding its role in T1D. In this review, we discuss recent findings suggesting that splicing events occurring in both immune and pancreatic β cells contribute to the pathogenesis of T1D. Splicing switches in T cells and in lymph node stromal cells are involved in the modulation of the immune response against β cells, while β cells exposed to pro-inflammatory cytokines activate complex splicing networks that modulate β cell viability, expression of neoantigens and susceptibility to immune-induced stress. Unveiling the role of AS in β cell functional loss and death will increase our understanding of T1D pathogenesis and may open new avenues for disease prevention and therapy.
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Affiliation(s)
- Jonàs Juan-Mateu
- Medical FacultyULB Center for Diabetes Research and Welbio, Université Libre de Bruxelles (ULB), Route de Lennik, 808 - CP618, B-1070 Brussels, Belgium
| | - Olatz Villate
- Medical FacultyULB Center for Diabetes Research and Welbio, Université Libre de Bruxelles (ULB), Route de Lennik, 808 - CP618, B-1070 Brussels, Belgium
| | - Décio L Eizirik
- Medical FacultyULB Center for Diabetes Research and Welbio, Université Libre de Bruxelles (ULB), Route de Lennik, 808 - CP618, B-1070 Brussels, Belgium
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Kodama K, Zhao Z, Toda K, Yip L, Fuhlbrigge R, Miao D, Fathman CG, Yamada S, Butte AJ, Yu L. Expression-Based Genome-Wide Association Study Links Vitamin D-Binding Protein With Autoantigenicity in Type 1 Diabetes. Diabetes 2016; 65:1341-9. [PMID: 26983959 PMCID: PMC4839207 DOI: 10.2337/db15-1308] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 02/22/2016] [Indexed: 12/18/2022]
Abstract
Type 1 diabetes (T1D) is caused by autoreactive T cells that recognize pancreatic islet antigens and destroy insulin-producing β-cells. This attack results from a breakdown in tolerance for self-antigens, which is controlled by ectopic antigen expression in the thymus and pancreatic lymph nodes (PLNs). The autoantigens known to be involved include a set of islet proteins, such as insulin, GAD65, IA-2, and ZnT8. In an attempt to identify additional antigenic proteins, we performed an expression-based genome-wide association study using microarray data from 118 arrays of the thymus and PLNs of T1D mice. We ranked all 16,089 protein-coding genes by the likelihood of finding repeated differential expression and the degree of tissue specificity for pancreatic islets. The top autoantigen candidate was vitamin D-binding protein (VDBP). T-cell proliferation assays showed stronger T-cell reactivity to VDBP compared with control stimulations. Higher levels and frequencies of serum anti-VDBP autoantibodies (VDBP-Abs) were identified in patients with T1D (n = 331) than in healthy control subjects (n = 77). Serum vitamin D levels were negatively correlated with VDBP-Ab levels in patients in whom T1D developed during the winter. Immunohistochemical localization revealed that VDBP was specifically expressed in α-cells of pancreatic islets. We propose that VDBP could be an autoantigen in T1D.
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Affiliation(s)
- Keiichi Kodama
- Institute for Computational Health Sciences, Department of Pediatrics, University of California, San Francisco, San Francisco, CA
| | - Zhiyuan Zhao
- Barbara Davis Center for Childhood Diabetes, University of Colorado Denver, Aurora, CO
| | - Kyoko Toda
- Biomedical Research Center, Kitasato Institute Hospital, Kitasato University, Tokyo, Japan
| | - Linda Yip
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA
| | - Rebecca Fuhlbrigge
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA
| | - Dongmei Miao
- Barbara Davis Center for Childhood Diabetes, University of Colorado Denver, Aurora, CO
| | - C Garrison Fathman
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA
| | - Satoru Yamada
- Diabetes Center, Kitasato Institute Hospital, Kitasato University, Tokyo, Japan
| | - Atul J Butte
- Institute for Computational Health Sciences, Department of Pediatrics, University of California, San Francisco, San Francisco, CA
| | - Liping Yu
- Barbara Davis Center for Childhood Diabetes, University of Colorado Denver, Aurora, CO
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Dajani R, Li J, Wei Z, Glessner JT, Chang X, Cardinale CJ, Pellegrino R, Wang T, Hakooz N, Khader Y, Sheshani A, Zandaki D, Hakonarson H. CNV Analysis Associates AKNAD1 with Type-2 Diabetes in Jordan Subpopulations. Sci Rep 2015; 5:13391. [PMID: 26292654 PMCID: PMC4543987 DOI: 10.1038/srep13391] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 06/15/2015] [Indexed: 12/27/2022] Open
Abstract
Previous studies have identified a number of single nucleotide polymorphisms (SNPs) associated with type-2 diabetes (T2D), but copy number variation (CNV) association has rarely been addressed, especially in populations from Jordan. To investigate CNV associations for T2D in populations in Jordan, we conducted a CNV analysis based on intensity data from genome-wide SNP array, including 34 T2D cases and 110 healthy controls of Chechen ethnicity, as well as 34 T2D cases and 106 healthy controls of Circassian ethnicity. We found a CNV region in protein tyrosine phosphatase receptor type D (PTPRD) with significant association with T2D. PTPRD has been reported to be associated with T2D in genome-wide association studies (GWAS). We additionally identified 16 CNV regions associated with T2D which overlapped with gene exons. Of particular interest, a CNV region in the gene AKNA Domain Containing 1 (AKNAD1) surpassed the experiment-wide significance threshold. Endoplasmic reticulum (ER)-related pathways were significantly enriched among genes which are predicted to be functionally associated with human or mouse homologues of AKNAD1. This is the first CNV analysis of a complex disease in populations of Jordan. We identified and experimentally validated a significant CNVR in gene AKNAD1 associated with T2D.
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Affiliation(s)
- Rana Dajani
- Department of Biology and Biotechnology, Hashemite University, Zarqa, Jordan.,Cell Therapy Center, University of Jordan, Amman, Jordan
| | - Jin Li
- Center for Applied Genomics, Abramson Research Center, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Zhi Wei
- Department of Computer Science, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Joseph T Glessner
- Center for Applied Genomics, Abramson Research Center, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Xiao Chang
- Center for Applied Genomics, Abramson Research Center, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Christopher J Cardinale
- Center for Applied Genomics, Abramson Research Center, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Renata Pellegrino
- Center for Applied Genomics, Abramson Research Center, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Tiancheng Wang
- Center for Applied Genomics, Abramson Research Center, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nancy Hakooz
- Department of Biopharmaceutics and Clinical Pharmacy Faculty of Pharmacy-University of Jordan, Amman, Jordan.,Faculty of pharmacy, Zarqa University, Zarqa, Jordan
| | - Yousef Khader
- Department of Community Medicine, Public Health and Family Medicine, Faculty of Medicine, Jordan University for Science and Technology, Irbid, Jordan
| | - Amina Sheshani
- Department of Biology and Biotechnology, Hashemite University, Zarqa, Jordan
| | - Duaa Zandaki
- Department of Biology and Biotechnology, Hashemite University, Zarqa, Jordan
| | - Hakon Hakonarson
- Center for Applied Genomics, Abramson Research Center, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.,Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.,Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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15
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Mahmoud MH, Badr G, Badr BM, Kassem AU, Mohamed MS. Elevated IFN-alpha/beta levels in a streptozotocin-induced type I diabetic mouse model promote oxidative stress and mediate depletion of spleen-homing CD8+ T cells by apoptosis through impaired CCL21/CCR7 axis and IL-7/CD127 signaling. Cell Signal 2015; 27:2110-9. [PMID: 26192098 DOI: 10.1016/j.cellsig.2015.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 06/27/2015] [Accepted: 07/01/2015] [Indexed: 12/15/2022]
Abstract
Type 1 diabetes mellitus (T1D) is associated with increased type 1 interferon (IFN) levels and subsequent severe defects in lymphocyte function, which increase susceptibility to infections. The blockade of type 1 IFN receptor 1 (IFNAR1) in non-obese diabetic mice has been shown to delay T1D onset and decrease T1D incidence by enhancing spleen CD4+ T cells and restoring B cell function. However, the effect of type 1 IFN blockade during T1D on splenic CD8+ T cells has not previously been studied. Therefore, we investigated, for the first time, the effect of IFNAR1 blockade on the survival and architecture of spleen-homing CD8+ T cells in a streptozotocin-induced T1D mouse model. Three groups of mice were examined: a non-diabetic control group; a diabetic group; and a diabetic group treated with an anti-IFNAR1 blocking antibody. We observed that T1D induction was accompanied by a marked destruction of β cells followed by a marked reduction in insulin levels and increased IFN-α and IFN-β levels in the diabetic group. The diabetic mice also exhibited many abnormal changes including an elevation in blood and spleen free radical (reactive oxygen species and nitric oxide) and pro-inflammatory cytokine (IL-6 and TNF-α) levels, a significant decrease in IL-7 levels, and subsequently, a significant decrease in the numbers of spleen-homing CD8+ T cells. This decrease in spleen-homing CD8+ T cells resulted from a marked reduction in the CCL21-mediated entry of CD8+ T cells into the spleen and from increased apoptosis due to a marked reduction in IL-7-mediated STAT5 and AKT phosphorylation. Interestingly, type 1 IFN signaling blockade in diabetic mice significantly restored the numbers of splenic CD8+ T cells by restoring free radical, pro-inflammatory cytokine and IL-7 levels. These effects subsequently rescued splenic CD8+ T cells from apoptosis through a mechanism that was dependent upon CCL21- and IL-7-mediated signaling. Our data suggest that type 1 IFN is an essential mediator of pathogenesis in T1D and that this role results from the negative effect of IFN signaling on the survival of splenic CD8+ T cells.
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Affiliation(s)
- Mohamed H Mahmoud
- Deanship of Scientific Research, King Saud University, Riyadh, Saudi Arabia; Food Science and Nutrition Department, National Research Center, Dokki, Cairo, Egypt
| | - Gamal Badr
- Laboratory of Immunology & Molecular Physiology, Zoology Department, Faculty of Science, Assiut University, 71516 Assiut, Egypt. http://www.aun.edu.eg/
| | - Badr Mohamed Badr
- Radiation Biology Department, National Centre for Radiation Research and Technology (NCRRT), Cairo, Egypt
| | - Ahmad Usama Kassem
- Laboratory of Immunology & Molecular Physiology, Zoology Department, Faculty of Science, Assiut University, 71516 Assiut, Egypt
| | - Mahmoud Shaaban Mohamed
- Laboratory of Immunology & Molecular Physiology, Zoology Department, Faculty of Science, Assiut University, 71516 Assiut, Egypt
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16
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Yip L, Fuhlbrigge R, Taylor C, Creusot RJ, Nishikawa-Matsumura T, Whiting CC, Schartner JM, Akter R, von Herrath M, Fathman CG. Inflammation and hyperglycemia mediate Deaf1 splicing in the pancreatic lymph nodes via distinct pathways during type 1 diabetes. Diabetes 2015; 64:604-17. [PMID: 25187368 PMCID: PMC4303971 DOI: 10.2337/db14-0803] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Peripheral tolerance is partially controlled by the expression of peripheral tissue antigens (PTAs) in lymph node stromal cells (LNSCs). We previously identified a transcriptional regulator, deformed epidermal autoregulatory factor 1 (Deaf1), that can regulate PTA expression in LNSCs of the pancreatic lymph nodes (PLNs). During the pathogenesis of type 1 diabetes (T1D), Deaf1 is spliced to form the dominant-negative isoform Deaf1-Var1. Here we show that Deaf1-Var1 expression correlates with the severity of disease in NOD mice and is reduced in the PLNs of mice that do not develop hyperglycemia. Inflammation and hyperglycemia independently drive Deaf1 splicing through activation of the splicing factors Srsf10 and Ptbp2, respectively. Inflammation induced by injection of activated splenocytes increased Deaf1-Var1 and Srsf10, but not Ptbp2, in the PLNs of NOD.SCID mice. Hyperglycemia induced by treatment with the insulin receptor agonist S961 increased Deaf1-Var1 and Ptbp2, but not Srsf10, in the PLNs of NOD.B10 and NOD mice. Overexpression of PTBP2 and/or SRSF10 also increased human DEAF1-VAR1 and reduced PTA expression in HEK293T cells. These data suggest that during the progression of T1D, inflammation and hyperglycemia mediate the splicing of DEAF1 and loss of PTA expression in LNSCs by regulating the expression of SRSF10 and PTBP2.
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Affiliation(s)
- Linda Yip
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University, Stanford, CA
| | - Rebecca Fuhlbrigge
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University, Stanford, CA
| | - Cariel Taylor
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University, Stanford, CA
| | - Remi J Creusot
- Department of Medicine, Columbia Center for Translational Immunology and Naomi Berrie Diabetes Center, Columbia University Medical Center, New York, NY
| | | | - Chan C Whiting
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University, Stanford, CA
| | - Jill M Schartner
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University, Stanford, CA
| | - Rahima Akter
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University, Stanford, CA
| | - Matthias von Herrath
- Type 1 Diabetes Center, The La Jolla Institute for Allergy and Immunology, La Jolla, CA
| | - C Garrison Fathman
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University, Stanford, CA
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17
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Dolenšek J, Rupnik MS, Stožer A. Structural similarities and differences between the human and the mouse pancreas. Islets 2015; 7:e1024405. [PMID: 26030186 PMCID: PMC4589993 DOI: 10.1080/19382014.2015.1024405] [Citation(s) in RCA: 202] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/20/2015] [Accepted: 02/23/2015] [Indexed: 02/08/2023] Open
Abstract
Mice remain the most studied animal model in pancreas research. Since the findings of this research are typically extrapolated to humans, it is important to understand both similarities and differences between the 2 species. Beside the apparent difference in size and macroscopic organization of the organ in the 2 species, there are a number of less evident and only recently described differences in organization of the acinar and ductal exocrine tissue, as well as in the distribution, composition, and architecture of the endocrine islets of Langerhans. Furthermore, the differences in arterial, venous, and lymphatic vessels, as well as innervation are potentially important. In this article, the structure of the human and the mouse pancreas, together with the similarities and differences between them are reviewed in detail in the light of conceivable repercussions for basic research and clinical application.
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Affiliation(s)
- Jurij Dolenšek
- Institute of Physiology; Faculty of Medicine; University of Maribor; Maribor, Slovenia
| | - Marjan Slak Rupnik
- Institute of Physiology; Faculty of Medicine; University of Maribor; Maribor, Slovenia
- Centre for Open Innovations and Research Core@UM; University of Maribor; Maribor, Slovenia
- Institute of Physiology; Center for Physiology and Pharmacology; Medical University of Vienna; Vienna, Austria
| | - Andraž Stožer
- Institute of Physiology; Faculty of Medicine; University of Maribor; Maribor, Slovenia
- Centre for Open Innovations and Research Core@UM; University of Maribor; Maribor, Slovenia
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18
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Autoreactive T cells specific for insulin B:11-23 recognize a low-affinity peptide register in human subjects with autoimmune diabetes. Proc Natl Acad Sci U S A 2014; 111:14840-5. [PMID: 25267644 DOI: 10.1073/pnas.1416864111] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Previous studies in type 1 diabetes (T1D) in the nonobese diabetic mouse demonstrated that a crucial insulin epitope (B:9-23) is presented to diabetogenic CD4 T cells by IA(g7) in a weakly bound register. The importance of antigenic peptides with low-affinity HLA binding in human autoimmune disease remains less clear. The objective of this study was to investigate T-cell responses to a low-affinity self-epitope in subjects with T1D. HLA-DQ8 tetramers loaded with a modified insulin peptide designed to improve binding the low-affinity register were used to visualize T-cell responses following in vitro stimulation. Positive responses were only detectable in T1D patients. Because the immunogenic register of B:9-23 presented by DQ8 has not been conclusively demonstrated, T-cell assays using substituted peptides and DQ8 constructs engineered to express and present B:9-23 in fixed binding registers were used to determine the immunogenic register of this peptide. Tetramer-positive T-cell clones isolated from T1D subjects that responded to stimulation by B:11-23 peptide and denatured insulin protein were conclusively shown to recognize B:11-23 bound to HLA-DQ8 in the low-affinity register 3. These T cells also responded to homologous peptides derived from microbial antigens, suggesting that their initial priming could occur via molecular mimicry. These results are in accord with prior observations from the nonobese diabetic mouse model, suggesting a mechanism shared by mouse and man through which T cells that recognize a weakly bound peptide can circumvent tolerance mechanisms and play a role in the initiation of autoimmune diseases, such as T1D.
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