1
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Shahin NN, Shaker OG, Mahmoud MO. GOAT rs10096097 and CREB1 rs6740584 single nucleotide polymorphisms are associated with type 2 diabetes mellitus in Egyptians. Arch Pharm (Weinheim) 2024; 357:e2400011. [PMID: 38713912 DOI: 10.1002/ardp.202400011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 04/14/2024] [Accepted: 04/17/2024] [Indexed: 05/09/2024]
Abstract
Diabetes mellitus (DM) is a chronic disorder that affects nearly half a billion people around the world and causes millions of deaths annually. Treatment of diabetes or related complications represents an economic burden not only for developing countries but also for the developed ones. Hence, new efficient therapeutic and preventive strategies and screening tools are necessary. The current work aimed to assess the potential association of single nucleotide polymorphisms (SNPs) in ghrelin O-acyltransferase (GOAT) rs10096097, cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) rs6740584, and v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA) rs62521874 genes with type 2 DM susceptibility in Egyptians. A total of 96 patients with type 2 DM along with 72 healthy individuals participated in this study. Genotyping was executed via real-time polymerase chain reaction (PCR), and the serum protein levels of GOAT, CREB, and MafA were measured by enzyme-linked immunosorbent assay (ELISA). Genotyping revealed a significant association of GOAT rs10096097 and CREB1 rs6740584 SNPs with type 2 diabetes risk, with significantly higher GOAT rs10096097 G allele and CREB1 rs6740584 T allele frequencies in diabetic patients than in controls. However, insignificant association was identified between the MafA rs62521874 SNP and diabetes in the examined sample of the Egyptian residents. Serum GOAT, CREB1, and MafA protein levels did not vary significantly between diabetic and control individuals. Yet, significant variation in serum GOAT and CREB1 levels was detected between CREB1 rs6740584 genotypes within the diabetic group, with CT and TT genotype carriers showing higher levels than AA genotype patients. GOAT rs10096097 and CREB1 rs6740584, but not MafA rs62521874, SNPs are associated with type 2 diabetes risk in the studied Egyptians.
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Affiliation(s)
- Nancy N Shahin
- Biochemistry Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Olfat G Shaker
- Medical Biochemistry and Molecular Biology Department, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Mohamed O Mahmoud
- Biochemistry Department, Faculty of Pharmacy, Beni-Suef University, Beni-Suef, Egypt
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2
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Narayan G, Ronima K R, Agrawal A, Thummer RP. An Insight into Vital Genes Responsible for β-cell Formation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1450:1-27. [PMID: 37432546 DOI: 10.1007/5584_2023_778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
The regulation of glucose homeostasis and insulin secretion by pancreatic β-cells, when disturbed, will result in diabetes mellitus. Replacement of dysfunctional or lost β-cells with fully functional ones can tackle the problem of β-cell generation in diabetes mellitus. Various pancreatic-specific genes are expressed during different stages of development, which have essential roles in pancreatogenesis and β-cell formation. These factors play a critical role in cellular-based studies like transdifferentiation or de-differentiation of somatic cells to multipotent or pluripotent stem cells and their differentiation into functional β-cells. This work gives an overview of crucial transcription factors expressed during various stages of pancreas development and their role in β-cell specification. In addition, it also provides a perspective on the underlying molecular mechanisms.
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Affiliation(s)
- Gloria Narayan
- Laboratory for Stem Cell Engineering and Regenerative Medicine, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Ronima K R
- Laboratory for Stem Cell Engineering and Regenerative Medicine, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Akriti Agrawal
- Laboratory for Stem Cell Engineering and Regenerative Medicine, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Rajkumar P Thummer
- Laboratory for Stem Cell Engineering and Regenerative Medicine, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India.
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3
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Bele S, Wokasch AS, Gannon M. Epigenetic modulation of cell fate during pancreas development. TRENDS IN DEVELOPMENTAL BIOLOGY 2023; 16:1-27. [PMID: 38873037 PMCID: PMC11173269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
Epigenetic modifications to DNA and its associated proteins affect cell plasticity and cell fate restrictions throughout embryonic development. Development of the vertebrate pancreas is characterized by initial is an over-lapping expression of a set of transcriptional regulators in a defined region of the posterior foregut endoderm that collectively promote pancreas progenitor specification and proliferation. As development progresses, these transcription factors segregate into distinct pancreatic lineages, with some being maintained in specific subsets of terminally differentiated pancreas cell types throughout adulthood. Here we describe the progressive stages and cell fate restrictions that occur during pancreas development and the relevant known epigenetic regulatory events that drive the dynamic expression patterns of transcription factors that regulate pancreas development. In addition, we highlight how changes in epigenetic marks can affect susceptibility to pancreas diseases (such as diabetes), adult pancreas cell plasticity, and the ability to derive replacement insulin-producing β cells for the treatment of diabetes.
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Affiliation(s)
- Shilpak Bele
- Department of Medicine, Vanderbilt University Medical Center, 2213 Garland Avenue, Nashville, TN, 37232, USA
| | - Anthony S. Wokasch
- Department of Cell and Developmental Biology, Vanderbilt University, 2213 Garland Avenue, Nashville, TN, 37232, USA
| | - Maureen Gannon
- Department of Medicine, Vanderbilt University Medical Center, 2213 Garland Avenue, Nashville, TN, 37232, USA
- Department of Cell and Developmental Biology, Vanderbilt University, 2213 Garland Avenue, Nashville, TN, 37232, USA
- Department of Veterans Affairs Tennessee Valley Authority, Research Division, 1310 24 Avenue South, Nashville, TN, 37212, USA
- Department of Molecular Physiology and Biophysics, 2213 Garland Avenue, Nashville, TN, 37232, USA
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4
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Liot S, El Kholti N, Balas J, Genestier L, Verrier B, Valcourt U, Lambert E. Development of thymic tumor in [LSL:Kras G12D; Pdx1-CRE] mice, an adverse effect associated with accelerated pancreatic carcinogenesis. Sci Rep 2021; 11:15075. [PMID: 34302028 PMCID: PMC8302691 DOI: 10.1038/s41598-021-94566-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/08/2021] [Indexed: 12/18/2022] Open
Abstract
Pancreatic Ductal AdenoCarcinoma (PDAC) represents about 90% of pancreatic cancers. It is one of the most aggressive cancer, with a 5-year survival rate below 10% due to late diagnosis and poor therapeutic efficiency. This bad prognosis thus encourages intense research in order to better understand PDAC pathogenesis and molecular basis leading to the development of innovative therapeutic strategies. This research frequently involves the KC (LSL:KrasG12D;Pdx1-CRE) genetically engineered mouse model, which leads to pancreatic cancer predisposition. However, as frequently encountered in animal models, the KC mouse model also exhibits biases. Herein, we report a new adverse effect of KrasG12D mutation in KC mouse model. In our hands, 10% of KC mice developed clinical signs reaching pre-defined end-points between 100- and 150-days post-parturition, and associated with large thymic mass development. Histological and genetic analyses of this massive thymus enabled us (1) to characterize it as a highly proliferative thymic lymphoma and (2) to detect the unexpected recombination of the Lox-STOP-Lox cassette upstream KrasG12D allele and subsequent KRASG12D protein expression in all cells composing thymic masses. Finally, we highlighted that development of such thymic tumor was associated with accelerated pancreatic carcinogenesis, immune compartment disorganization, and in some cases, lung malignancies.
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Affiliation(s)
- Sophie Liot
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique (LBTI), UMR CNRS 5305, Université Claude Bernard Lyon 1, Institut de Biologie et Chimie Des Protéines, 7, passage du Vercors, 69367, Lyon Cedex 07, France
| | - Naïma El Kholti
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique (LBTI), UMR CNRS 5305, Université Claude Bernard Lyon 1, Institut de Biologie et Chimie Des Protéines, 7, passage du Vercors, 69367, Lyon Cedex 07, France
| | - Jonathan Balas
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique (LBTI), UMR CNRS 5305, Université Claude Bernard Lyon 1, Institut de Biologie et Chimie Des Protéines, 7, passage du Vercors, 69367, Lyon Cedex 07, France
| | - Laurent Genestier
- UR LIB « Lymphoma Immuno-Biology", Université Claude Bernard Lyon I, Lyon, France
| | - Bernard Verrier
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique (LBTI), UMR CNRS 5305, Université Claude Bernard Lyon 1, Institut de Biologie et Chimie Des Protéines, 7, passage du Vercors, 69367, Lyon Cedex 07, France
| | - Ulrich Valcourt
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique (LBTI), UMR CNRS 5305, Université Claude Bernard Lyon 1, Institut de Biologie et Chimie Des Protéines, 7, passage du Vercors, 69367, Lyon Cedex 07, France
| | - Elise Lambert
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique (LBTI), UMR CNRS 5305, Université Claude Bernard Lyon 1, Institut de Biologie et Chimie Des Protéines, 7, passage du Vercors, 69367, Lyon Cedex 07, France.
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5
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Liu M, Huang Y, Xu X, Li X, Alam M, Arunagiri A, Haataja L, Ding L, Wang S, Itkin-Ansari P, Kaufman RJ, Tsai B, Qi L, Arvan P. Normal and defective pathways in biogenesis and maintenance of the insulin storage pool. J Clin Invest 2021; 131:142240. [PMID: 33463547 PMCID: PMC7810482 DOI: 10.1172/jci142240] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Both basal and glucose-stimulated insulin release occur primarily by insulin secretory granule exocytosis from pancreatic β cells, and both are needed to maintain normoglycemia. Loss of insulin-secreting β cells, accompanied by abnormal glucose tolerance, may involve simple exhaustion of insulin reserves (which, by immunostaining, appears as a loss of β cell identity), or β cell dedifferentiation, or β cell death. While various sensing and signaling defects can result in diminished insulin secretion, somewhat less attention has been paid to diabetes risk caused by insufficiency in the biosynthetic generation and maintenance of the total insulin granule storage pool. This Review offers an overview of insulin biosynthesis, beginning with the preproinsulin mRNA (translation and translocation into the ER), proinsulin folding and export from the ER, and delivery via the Golgi complex to secretory granules for conversion to insulin and ultimate hormone storage. All of these steps are needed for generation and maintenance of the total insulin granule pool, and defects in any of these steps may, weakly or strongly, perturb glycemic control. The foregoing considerations have obvious potential relevance to the pathogenesis of type 2 diabetes and some forms of monogenic diabetes; conceivably, several of these concepts might also have implications for β cell failure in type 1 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Maroof Alam
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Li Ding
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Shusen Wang
- Organ Transplant Center, Tianjin First Central Hospital, Tianjin, China
| | | | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, and
| | - Ling Qi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
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6
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Abstract
The conventional perception asserts that immunology is the science of ‘discrimination’ between self and non-self. This concept is however no longer tenable as effector cells of the adaptive immune system are first conditioned to be tolerant to the body’s own antigens, collectively known as self until now. Only then attain these effectors the responsiveness to non-self. The acquisition of this essential state of tolerance to self occurs for T cells in the thymus, the last major organ of our body that revealed its intricate function in health and disease. The ‘thymus’ as an anatomical notion was first notably documented in Ancient Greece although our present understanding of the organ’s functions was only deciphered commencing in the 1960s. In the late 1980s, the thymus was identified as the site where clones of cells reactive to self, termed ‘forbidden’ thymocytes, are physically depleted as the result of a process now known as negative selection. The recognition of this mechanism further contributed to the belief that the central rationale of immunology as a science lies in the distinction between self and non-self. This review will discuss the evidence that the thymus serves as a unique lymphoid organ able to instruct T cells to recognize and be tolerant to harmless self before adopting the capacity to defend the body against potentially injurious non-self-antigens presented in the context of different challenges from infections to exposure to malignant cells. The emerging insight into the thymus’ cardinal functions now also provides an opportunity to exploit this knowledge to develop novel strategies that specifically prevent or even treat organ-specific autoimmune diseases.
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7
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Singh T, Colberg JK, Sarmiento L, Chaves P, Hansen L, Bsharat S, Cataldo LR, Dudenhöffer-Pfeifer M, Fex M, Bryder D, Holmberg D, Sitnicka E, Cilio C, Prasad RB, Artner I. Loss of MafA and MafB expression promotes islet inflammation. Sci Rep 2019; 9:9074. [PMID: 31235823 PMCID: PMC6591483 DOI: 10.1038/s41598-019-45528-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 06/06/2019] [Indexed: 12/15/2022] Open
Abstract
Maf transcription factors are critical regulators of beta-cell function. We have previously shown that reduced MafA expression in human and mouse islets is associated with a pro-inflammatory gene signature. Here, we investigate if the loss of Maf transcription factors induced autoimmune processes in the pancreas. Transcriptomics analysis showed expression of pro-inflammatory as well as immune cell marker genes. However, clusters of CD4+ T and B220+ B cells were associated primarily with adult MafA−/−MafB+/−, but not MafA−/− islets. MafA expression was detected in the thymus, lymph nodes and bone marrow suggesting a novel role of MafA in regulating immune-cell function. Analysis of pancreatic lymph node cells showed activation of CD4+ T cells, but lack of CD8+ T cell activation which also coincided with an enrichment of naïve CD8+ T cells. Further analysis of T cell marker genes revealed a reduction of T cell receptor signaling gene expression in CD8, but not in CD4+ T cells, which was accompanied with a defect in early T cell receptor signaling in mutant CD8+ T cells. These results suggest that loss of MafA impairs both beta- and T cell function affecting the balance of peripheral immune responses against islet autoantigens, resulting in local inflammation in pancreatic islets.
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Affiliation(s)
- Tania Singh
- Stem Cell Center, Lund University, Klinikgatan 26, Lund, 22184, Sweden.,Lund University Diabetes Center, Jan Waldenströms gata 35, Malmö, 21428, Sweden
| | - Jesper K Colberg
- Stem Cell Center, Lund University, Klinikgatan 26, Lund, 22184, Sweden
| | - Luis Sarmiento
- Lund University Diabetes Center, Jan Waldenströms gata 35, Malmö, 21428, Sweden
| | - Patricia Chaves
- Stem Cell Center, Lund University, Klinikgatan 26, Lund, 22184, Sweden
| | - Lisbeth Hansen
- Lund University Diabetes Center, Jan Waldenströms gata 35, Malmö, 21428, Sweden
| | - Sara Bsharat
- Stem Cell Center, Lund University, Klinikgatan 26, Lund, 22184, Sweden.,Lund University Diabetes Center, Jan Waldenströms gata 35, Malmö, 21428, Sweden
| | - Luis R Cataldo
- Stem Cell Center, Lund University, Klinikgatan 26, Lund, 22184, Sweden.,Lund University Diabetes Center, Jan Waldenströms gata 35, Malmö, 21428, Sweden
| | | | - Malin Fex
- Lund University Diabetes Center, Jan Waldenströms gata 35, Malmö, 21428, Sweden
| | - David Bryder
- Stem Cell Center, Lund University, Klinikgatan 26, Lund, 22184, Sweden
| | - Dan Holmberg
- Lund University Diabetes Center, Jan Waldenströms gata 35, Malmö, 21428, Sweden
| | - Ewa Sitnicka
- Stem Cell Center, Lund University, Klinikgatan 26, Lund, 22184, Sweden
| | - Corrado Cilio
- Lund University Diabetes Center, Jan Waldenströms gata 35, Malmö, 21428, Sweden
| | - Rashmi B Prasad
- Lund University Diabetes Center, Jan Waldenströms gata 35, Malmö, 21428, Sweden
| | - Isabella Artner
- Stem Cell Center, Lund University, Klinikgatan 26, Lund, 22184, Sweden. .,Lund University Diabetes Center, Jan Waldenströms gata 35, Malmö, 21428, Sweden.
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8
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Geenen V, Trussart C, Michaux H, Halouani A, Jaïdane H, Collée C, Renard C, Daukandt M, Ledent P, Martens H. The presentation of neuroendocrine self-peptides in the thymus: an essential event for individual life and vertebrate survival. Ann N Y Acad Sci 2019; 1455:113-125. [PMID: 31008523 PMCID: PMC6899491 DOI: 10.1111/nyas.14089] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/27/2019] [Accepted: 03/10/2019] [Indexed: 12/12/2022]
Abstract
Confirming Burnet's early hypothesis, elimination of self‐reactive T cells in the thymus was demonstrated in the late 1980s, and an important question immediately arose about the nature of the self‐peptides expressed in the thymus. Many genes encoding neuroendocrine‐related and tissue‐restricted antigens (TRAs) are transcribed in thymic epithelial cells (TECs). They are then processed for presentation by proteins of the major histocompatibility complex (MHC) expressed by TECs and thymic dendritic cells. MHC presentation of self‐peptides in the thymus programs self‐tolerance by two complementary mechanisms: (1) negative selection of self‐reactive “forbidden” T cell clones starting already in fetal life, and (2) generation of self‐specific thymic regulatory T lymphocytes (tTreg cells), mainly after birth. Many studies, including the discovery of the transcription factors autoimmune regulator (AIRE) and fasciculation and elongation protein zeta family zinc finger (FEZF2), have shown that a defect in thymus central self‐tolerance is the earliest event promoting autoimmunity. AIRE and FEZF2 control the level of transcription of many neuroendocrine self‐peptides and TRAs in the thymic epithelium. Furthermore, AIRE and FEZF2 mutations are associated with the development of autoimmunity in peripheral organs. The discovery of the intrathymic presentation of self‐peptides has revolutionized our knowledge of immunology and is opening novel avenues for prevention/treatment of autoimmunity.
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Affiliation(s)
- Vincent Geenen
- GIGA Institute, University of Liège, Liège-Sart Tilman, Belgium
| | | | - Hélène Michaux
- GIGA Institute, University of Liège, Liège-Sart Tilman, Belgium
| | - Aymen Halouani
- GIGA Institute, University of Liège, Liège-Sart Tilman, Belgium.,Faculty of Sciences and Faculty of Pharmacy, University of Tunis El Manar, Monastir, Tunisia
| | - Hela Jaïdane
- Faculty of Sciences and Faculty of Pharmacy, University of Tunis El Manar, Monastir, Tunisia
| | - Caroline Collée
- GIGA Institute, University of Liège, Liège-Sart Tilman, Belgium
| | - Chantal Renard
- GIGA Institute, University of Liège, Liège-Sart Tilman, Belgium
| | - Marc Daukandt
- X-Press Biologics, Industrial Park of Milmort, Liège, Belgium
| | - Philippe Ledent
- X-Press Biologics, Industrial Park of Milmort, Liège, Belgium
| | - Henri Martens
- GIGA Institute, University of Liège, Liège-Sart Tilman, Belgium
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9
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Zhu Y, Liu Q, Zhou Z, Ikeda Y. PDX1, Neurogenin-3, and MAFA: critical transcription regulators for beta cell development and regeneration. Stem Cell Res Ther 2017; 8:240. [PMID: 29096722 PMCID: PMC5667467 DOI: 10.1186/s13287-017-0694-z] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Transcription factors regulate gene expression through binding to specific enhancer sequences. Pancreas/duodenum homeobox protein 1 (PDX1), Neurogenin-3 (NEUROG3), and V-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MAFA) are transcription factors critical for beta cell development and maturation. NEUROG3 is expressed in endocrine progenitor cells and controls islet differentiation and regeneration. PDX1 is essential for the development of pancreatic exocrine and endocrine cells including beta cells. PDX1 also binds to the regulatory elements and increases insulin gene transcription. Likewise, MAFA binds to the enhancer/promoter region of the insulin gene and drives insulin expression in response to glucose. In addition to those natural roles in beta cell development and maturation, ectopic expression of PDX1, NEUROG3, and/or MAFA has been successfully used to reprogram various cell types into insulin-producing cells in vitro and in vivo, such as pancreatic exocrine cells, hepatocytes, and pluripotent stem cells. Here, we review biological properties of PDX1, NEUROG3, and MAFA, and their applications and limitations for beta cell regenerative approaches. The primary source literature for this review was acquired using a PubMed search for articles published between 1990 and 2017. Search terms include diabetes, insulin, trans-differentiation, stem cells, and regenerative medicine.
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Affiliation(s)
- Yaxi Zhu
- Department of Molecular Medicine, Mayo Clinic, College of Medicine, 200 First St. SW, Rochester, MN, 55905, USA.,Institute of Metabolism and Endocrinology, The Second Xiangya Hospital, Key Laboratory of Diabetes Immunology, Ministry of Education, Central South University, National Clinical Research Center for Metabolic Diseases, 139 Middle Renmin Road, Changsha, Hunan Province, 410013, China
| | - Qian Liu
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, 139 Middle Renmin Road, Changsha, Hunan Province, 410013, China
| | - Zhiguang Zhou
- Institute of Metabolism and Endocrinology, The Second Xiangya Hospital, Key Laboratory of Diabetes Immunology, Ministry of Education, Central South University, National Clinical Research Center for Metabolic Diseases, 139 Middle Renmin Road, Changsha, Hunan Province, 410013, China
| | - Yasuhiro Ikeda
- Department of Molecular Medicine, Mayo Clinic, College of Medicine, 200 First St. SW, Rochester, MN, 55905, USA. .,Center for Regenerative Medicine, Mayo Clinic, College of Medicine, 200 First St. SW, Rochester, MN, 55905, USA.
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10
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Michaux H, Martens H, Jaïdane H, Halouani A, Hober D, Geenen V. How Does Thymus Infection by Coxsackievirus Contribute to the Pathogenesis of Type 1 Diabetes? Front Immunol 2015; 6:338. [PMID: 26175734 PMCID: PMC4485212 DOI: 10.3389/fimmu.2015.00338] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/17/2015] [Indexed: 12/16/2022] Open
Abstract
Through synthesis and presentation of neuroendocrine self-antigens by major histocompatibility complex proteins, thymic epithelial cells (TECs) play a crucial role in programing central immune self-tolerance to neuroendocrine functions. Insulin-like growth factor-2 (IGF-2) is the dominant gene/polypeptide of the insulin family that is expressed in TECs from different animal species and humans. Igf2 transcription is defective in the thymus of diabetes-prone bio-breeding rats, and tolerance to insulin is severely decreased in Igf2 (-/-) mice. For more than 15 years now, our group is investigating the hypothesis that, besides a pancreotropic action, infection by coxsackievirus B4 (CV-B4) could implicate the thymus as well, and interfere with the intrathymic programing of central tolerance to the insulin family and secondarily to insulin-secreting islet β cells. In this perspective, we have demonstrated that a productive infection of the thymus occurs after oral CV-B4 inoculation of mice. Moreover, our most recent data have demonstrated that CV-B4 infection of a murine medullary (m) TEC line induces a significant decrease in Igf2 expression and IGF-2 production. In these conditions, Igf1 expression was much less affected by CV-B4 infection, while Ins2 transcription was not detected in this cell line. Through the inhibition of Igf2 expression in TECs, CV-B4 infection could lead to a breakdown of central immune tolerance to the insulin family and promote an autoimmune response against insulin-secreting islet β cells. Our major research objective now is to understand the molecular mechanisms by which CV-B4 infection of TECs leads to a major decrease in Igf2 expression in these cells.
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Affiliation(s)
- Hélène Michaux
- Department of Biomedical and Preclinical Sciences, GIGA-I 3 Center of Immunoendocrinology, GIGA Research Institute, University of Liege , Liege , Belgium
| | - Henri Martens
- Department of Biomedical and Preclinical Sciences, GIGA-I 3 Center of Immunoendocrinology, GIGA Research Institute, University of Liege , Liege , Belgium
| | - Hela Jaïdane
- Laboratory of Virology LR99ES27, School of Pharmacy, University of Monastir , Monastir , Tunisia ; Faculty of Sciences of Tunis, University of Tunis El Manar , Tunis , Tunisia
| | - Aymen Halouani
- Laboratory of Virology LR99ES27, School of Pharmacy, University of Monastir , Monastir , Tunisia ; Faculty of Sciences of Tunis, University of Tunis El Manar , Tunis , Tunisia
| | - Didier Hober
- Laboratory of Virology EA3610, Centre Hospitalier Régional Universitaire de Lille, University of Lille 2 , Lille , France
| | - Vincent Geenen
- Department of Biomedical and Preclinical Sciences, GIGA-I 3 Center of Immunoendocrinology, GIGA Research Institute, University of Liege , Liege , Belgium
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11
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Ikegami H, Noso S, Babaya N, Kawabata Y. Genetics and pathogenesis of type 1 diabetes: prospects for prevention and intervention. J Diabetes Investig 2014; 2:415-20. [PMID: 24843523 PMCID: PMC4014898 DOI: 10.1111/j.2040-1124.2011.00176.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Type 1 diabetes is etiologically a multifactorial disease caused by a complex interaction of genetic and environmental factors, with the former consisting of multiple susceptibility genes. Identification of genes conferring susceptibility to type 1 diabetes would clarify etiological pathways in the development and progression of type 1 diabetes, leading to the establishment of effective methods for prevention and intervention of the disease. Among multiple susceptibility genes, HLA and INS are particularly important because of their contribution to tissue specificity in the autoimmune process. DRB1*04:05-DQB1*04:01 is associated with autoimmune type 1 diabetes, idiopathic fulminant type 1 diabetes and anti-islet autoimmunity in autoimmune thyroid diseases, suggesting that this haplotype is associated with beta-cell specificity in autoimmune diseases. Genes involved in the expression of insulin in the thymus contribute to beta-cell-specific autoimmune mechanisms in type 1 diabetes. These genes and pathways are important targets for tissue-specific prevention and intervention of type 1 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00176.x, 2011).
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Affiliation(s)
- Hiroshi Ikegami
- Department of Endocrinology, Metabolism and Diabetes, Kinki University School of Medicine, Osaka, Japan
| | - Shinsuke Noso
- Department of Endocrinology, Metabolism and Diabetes, Kinki University School of Medicine, Osaka, Japan
| | - Naru Babaya
- Department of Endocrinology, Metabolism and Diabetes, Kinki University School of Medicine, Osaka, Japan
| | - Yumiko Kawabata
- Department of Endocrinology, Metabolism and Diabetes, Kinki University School of Medicine, Osaka, Japan
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12
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Geenen V, Bodart G, Henry S, Michaux H, Dardenne O, Charlet-Renard C, Martens H, Hober D. Programming of neuroendocrine self in the thymus and its defect in the development of neuroendocrine autoimmunity. Front Neurosci 2013; 7:187. [PMID: 24137108 PMCID: PMC3797387 DOI: 10.3389/fnins.2013.00187] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 09/27/2013] [Indexed: 12/20/2022] Open
Abstract
For centuries after its first description by Galen, the thymus was considered as only a vestigial endocrine organ until the discovery in 1961 by Jacques FAP Miller of its essential role in the development of T (thymo-dependent) lymphocytes. A unique thymus first appeared in cartilaginous fishes some 500 million years ago, at the same time or shortly after the emergence of the adaptive (acquired) immune system. The thymus may be compared to a small brain or a computer highly specialized in the orchestration of central immunological self-tolerance. This was a necessity for the survival of species, given the potent evolutionary pressure imposed by the high risk of autotoxicity inherent in the stochastic generation of the diversity of immune cell receptors that characterize the adaptive immune response. A new paradigm of “neuroendocrine self-peptides” has been proposed, together with the definition of “neuroendocrine self.” Neuroendocrine self-peptides are secreted by thymic epithelial cells (TECs) not according to the classic model of neuroendocrine signaling, but are processed for presentation by, or in association with, the thymic major histocompatibility complex (MHC) proteins. The autoimmune regulator (AIRE) gene/protein controls the transcription of neuroendocrine genes in TECs. The presentation of self-peptides in the thymus is responsible for the clonal deletion of self-reactive T cells, which emerge during the random recombination of gene segments that encode variable parts of the T cell receptor for the antigen (TCR). At the same time, self-antigen presentation in the thymus generates regulatory T (Treg) cells that can inhibit, in the periphery, those self-reactive T cells that escaped negative selection in the thymus. Several arguments indicate that the origin of autoimmunity directed against neuroendocrine glands results primarily from a defect in the intrathymic programming of self-tolerance to neuroendocrine functions. This defect may be genetic or acquired, for example during an enteroviral infection. This novel knowledge of normal and pathologic functions of the thymus constitutes a solid basis for the development of a novel type of tolerogenic/negative self-vaccination against type 1 diabetes (T1D).
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Affiliation(s)
- Vincent Geenen
- Department of Biomedical and Preclinical Sciences, Center of Immunoendocrinology, GIGA Research Institute, Fund of Scientific Research, University of Liege Liege-Sart Tilman, Belgium
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13
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Kanatsuna N, Taneera J, Vaziri-Sani F, Wierup N, Larsson HE, Delli A, Skärstrand H, Balhuizen A, Bennet H, Steiner DF, Törn C, Fex M, Lernmark Å. Autoimmunity against INS-IGF2 protein expressed in human pancreatic islets. J Biol Chem 2013; 288:29013-23. [PMID: 23935095 DOI: 10.1074/jbc.m113.478222] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Insulin is a major autoantigen in islet autoimmunity and progression to type 1 diabetes. It has been suggested that the insulin B-chain may be critical to insulin autoimmunity in type 1 diabetes. INS-IGF2 consists of the preproinsulin signal peptide, the insulin B-chain, and eight amino acids of the C-peptide in addition to 138 amino acids from the IGF2 gene. We aimed to determine the expression of INS-IGF2 in human pancreatic islets and autoantibodies in newly diagnosed children with type 1 diabetes and controls. INS-IGF2, expressed primarily in beta cells, showed higher levels of expression in islets from normal compared with donors with either type 2 diabetes (p = 0.006) or high HbA1c levels (p < 0.001). INS-IGF2 autoantibody levels were increased in newly diagnosed patients with type 1 diabetes (n = 304) compared with healthy controls (n = 355; p < 0.001). Displacement with cold insulin and INS-IGF2 revealed that more patients than controls had doubly reactive insulin-INS-IGF2 autoantibodies. These data suggest that INS-IGF2, which contains the preproinsulin signal peptide, the B-chain, and eight amino acids of the C-peptide may be an autoantigen in type 1 diabetes. INS-IGF2 and insulin may share autoantibody-binding sites, thus complicating the notion that insulin is the primary autoantigen in type 1 diabetes.
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Affiliation(s)
- Norio Kanatsuna
- From the Department of Clinical Sciences, Lund University Diabetes Center, Lund University, Skåne University Hospital SUS, SE-205 02 Malmö, Sweden and
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14
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St-Jean JR, Ounissi-Benkalha H, Polychronakos C. Yeast one-hybrid screen of a thymus epithelial library identifies ZBTB7A as a regulator of thymic insulin expression. Mol Immunol 2013; 56:637-42. [PMID: 23911422 DOI: 10.1016/j.molimm.2013.05.238] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/28/2013] [Accepted: 05/28/2013] [Indexed: 12/20/2022]
Abstract
Insulin self-tolerance is, to a large extent, assured by the expression of small quantities of insulin by medullary thymic epithelial cells (mTECs). Regulation of thymic insulin expression differs from that in pancreas and its therapeutic manipulation could play an important role in the prevention of type 1 diabetes (T1D). Knowledge of the transcriptional regulators involved in the mTEC nuclear environment is essential for the development of such therapeutics. The yeast one-hybrid (Y1H) approach was used in order to identify such mTEC-specific nuclear proteins. We used a target composed of the human insulin gene promoter joined to the upstream class III VNTR allele, which is associated with both protection from T1D and higher thymic insulin expression, and a cDNA library from our insulin-producing mouse mTEC line. The Y1H screening allowed the identification of eleven proteins. An in vitro assay was used to confirm and quantify protein-DNA binding to the human insulin gene promoter alone or joined to a class I or class III VNTR allele, and identified the transcription factors ZBTB7A, JUN and EWSR1 as strong interacting partners. All three proteins could induce insulin expression in transfected HEK-293 cells, but ZBTB7A provided the most robust results especially in the presence of AIRE, with an additional 11-fold increase of the insulin mRNA levels from a co-transfected reporter driven by the class III VNTR allele. Thus, ZBTB7A is identified as a strong candidate for regulation of thymic insulin expression.
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Affiliation(s)
- Julien R St-Jean
- Laboratory of Endocrine Genetics, Department of Pediatrics, The McGill University Health Center, 4060 Ste-Catherine West, Montreal, Quebec, Canada H3Z 2Z3
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15
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Abstract
It is widely accepted that Type 1 diabetes is a complex disease. Genetic predisposition and environmental factors favour the triggering of autoimmune responses against pancreatic β-cells, eventually leading to β-cell destruction. Over 40 susceptibility loci have been identified, many now mapped to known genes, largely supporting a dominant role for an immune-mediated pathogenesis. This role is also supported by the identification of several islet autoantigens and antigen-specific responses in patients with recent onset diabetes and subjects with pre-diabetes. Increasing evidence suggests certain viruses as a common environmental factor, together with diet and the gut microbiome. Inflammation and insulin resistance are emerging as additional cofactors, which might be interrelated with environmental factors. The heterogeneity of disease progression and clinical manifestations is likely a reflection of this multifactorial pathogenesis. So far, clinical trials have been mostly ineffective in delaying progression to overt diabetes in relatives at increased risk, or in reducing further loss of insulin secretion in patients with new-onset diabetes. This limited success may reflect, in part, our incomplete understanding of key pathogenic mechanisms, the lack of truly robust biomarkers of both disease activity and β-cell destruction, and the inability to assess the relative contributions of various pathogenic mechanisms at various time points during the course of the natural history of Type 1 diabetes. Emerging data and a re-evaluation of histopathological, immunological and metabolic findings suggest the hypothesis that unknown mechanisms of β-cell dysfunction may be present at diagnosis, and may contribute to the development of hyperglycaemia and clinical symptoms.
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Affiliation(s)
- A Pugliese
- Diabetes Research Institute, Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Miami, Miller School of Medicine, Miami, FL, USA.
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16
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Abstract
Type 1 diabetes (T1D) is a chronic disease resulting from the selective autoimmune destruction of pancreatic islet β cells. The absence and/or breakdown of immune self-tolerance to islet β cells is now recognized as the essential cause for the development of the diabetogenic autoimmune response. For a long time, a failure in peripheral tolerogenic mechanisms was regarded as the main source of an inappropriate immune process directed against insulin-secreting β cells. While defective peripheral self-tolerance still deserves to be further investigated, the demonstration that all members of the insulin gene family are transcribed in thymic epithelial cells (TECs) of different species under the control of the AutoImmune REgulator (AIRE) gene/protein has highlighted the importance of central self-tolerance to insulin-secreting islet β cells. Moreover, there is now evidence that a primary or acquired failure in thymus-dependent central self-tolerance to β cells plays a primary role in T1D pathogenesis. This novel knowledge is currently translated into the development of innovative tolerogenic/regulatory approaches designed to reprogram the specific immune self-tolerance to islet β cells.
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Affiliation(s)
- Vincent Geenen
- University of Liege, GIGA-I3 Center of Immunology, CHU-B34, B-4000 Liege-Sart Tilman, Belgium.
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17
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Yang XY, Levi D, Ounissi-Benkalha H, Yu XY, Qu HQ, Polychronakos C, Du GH. Screening for novel lead compounds increasing insulin expression in medullary thymic epithelial cells. Eur J Pharmacol 2012; 688:84-9. [PMID: 22507222 DOI: 10.1016/j.ejphar.2012.03.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 03/16/2012] [Accepted: 03/23/2012] [Indexed: 12/17/2022]
Abstract
Insulin expression in the thymus has been implicated in regulating the negative selection of autoreactive T cells and in mediating the central immune tolerance to pancreatic beta-cells. Thymic insulin expression modulation might be an important drug target for preventing type 1 diabetes. We performed a high-throughput screening to identify compounds with such activity. A reporter plasmid was constructed with the human insulin promoter sequence including a short allele of the upstream variable number tandem repeat (VNTR) sequence (32 repeats), subcloned into the pGL4.17 vector. The plasmid was stably transfected into an insulin-transcribing medullary thymic epithelial cell (mTEC) line. Primary high-throughput screening assays were carried out by stimulating with candidate compounds for 24h, and the activity of luciferase was measured. Positive compounds were further validated by real-time PCR. Of 19,707 compounds, we identified one compound that could enhance mTEC insulin expression, as confirmed by real-time PCR. We also observed that transfection with the autoimmune regulator (AIRE) increased endogenous AIRE expression in mTECs. Our insulin-VNTRI-promoter reporter system is consistent with the insulin expression regulation in mTECs, and one compound that was identified could increase insulin expression in mTECs. A positive feedback effect of AIRE in mTECS was observed. Whether these efforts in murine thymus cells apply to humans remains to be determined.
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Affiliation(s)
- Xiu-Ying Yang
- Beijing Key Laboratory of Drug Targets Identification and Drug Screening, Institute of Materia Medica, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
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18
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Lin WY, Lee WC. Improving power of genome-wide association studies with weighted false discovery rate control and prioritized subset analysis. PLoS One 2012; 7:e33716. [PMID: 22496761 PMCID: PMC3322139 DOI: 10.1371/journal.pone.0033716] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 02/16/2012] [Indexed: 02/06/2023] Open
Abstract
The issue of large-scale testing has caught much attention with the advent of high-throughput technologies. In genomic studies, researchers are often confronted with a large number of tests. To make simultaneous inference for the many tests, the false discovery rate (FDR) control provides a practical balance between the number of true positives and the number of false positives. However, when few hypotheses are truly non-null, controlling the FDR may not provide additional advantages over controlling the family-wise error rate (e.g., the Bonferroni correction). To facilitate discoveries from a study, weighting tests according to prior information is a promising strategy. A 'weighted FDR control' (WEI) and a 'prioritized subset analysis' (PSA) have caught much attention. In this work, we compare the two weighting schemes with systematic simulation studies and demonstrate their use with a genome-wide association study (GWAS) on type 1 diabetes provided by the Wellcome Trust Case Control Consortium. The PSA and the WEI both can increase power when the prior is informative. With accurate and precise prioritization, the PSA can especially create substantial power improvements over the commonly-used whole-genome single-step FDR adjustment (i.e., the traditional un-weighted FDR control). When the prior is uninformative (true disease susceptibility regions are not prioritized), the power loss of the PSA and the WEI is almost negligible. However, a caution is that the overall FDR of the PSA can be slightly inflated if the prioritization is not accurate and precise. Our study highlights the merits of using information from mounting genetic studies, and provides insights to choose an appropriate weighting scheme to FDR control on GWAS.
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Affiliation(s)
- Wan-Yu Lin
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan.
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19
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Brezar V, Carel JC, Boitard C, Mallone R. Beyond the hormone: insulin as an autoimmune target in type 1 diabetes. Endocr Rev 2011; 32:623-69. [PMID: 21700723 DOI: 10.1210/er.2011-0010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Insulin is not only the hormone produced by pancreatic β-cells but also a key target antigen of the autoimmune islet destruction leading to type 1 diabetes. Despite cultural biases between the fields of endocrinology and immunology, these two facets should not be regarded separately, but rather harmonized in a unifying picture of diabetes pathogenesis. There is increasing evidence suggesting that metabolic factors (β-cell dysfunction, insulin resistance) and immunological components (inflammation and β-cell-directed adaptive immune responses) may synergize toward islet destruction, with insulin standing at the crossroad of these pathways. This concept further calls for a revision of the classical dichotomy between type 1 and type 2 diabetes because metabolic and immune mechanisms may both contribute to different extents to the development of different forms of diabetes. After providing a background on the mechanisms of β-cell autoimmunity, we will explain the role of insulin and its precursors as target antigens expressed not only by β-cells but also in the thymus. Available knowledge on the autoimmune antibody and T-cell responses against insulin will be summarized. A unifying scheme will be proposed to show how different aspects of insulin biology may lead to β-cell destruction and may be therapeutically exploited. We will argue about possible reasons why insulin remains the mainstay of metabolic control in type 1 diabetes but has so far failed to prevent or halt β-cell autoimmunity as an immune modulatory reagent.
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Affiliation(s)
- Vedran Brezar
- Institut National de la Santé et de la Recherche Médicale, Unité 986, DeAR Lab Avenir, Saint Vincent de Paul Hospital, and Paris Descartes University, 82 avenue Denfert Rochereau, 75674 Paris Cedex 14, France
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20
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Hang Y, Stein R. MafA and MafB activity in pancreatic β cells. Trends Endocrinol Metab 2011; 22:364-73. [PMID: 21719305 PMCID: PMC3189696 DOI: 10.1016/j.tem.2011.05.003] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 05/03/2011] [Accepted: 05/18/2011] [Indexed: 12/11/2022]
Abstract
Analyses in mouse models have revealed crucial roles for MafA (musculoaponeurotic fibrosarcoma oncogene family A) and MafB in islet β cells, with MafB being required during development and MafA in adults. These two closely related transcription factors regulate many genes essential for glucose sensing and insulin secretion in a cooperative and sequential manner. Significantly, the switch from MafB to MafA expression also appears to be vital for functional maturation of β cells produced by human embryonic stem (hES) cell differentiation. This review summarizes the discovery, distribution, and function of MafA and MafB in rodent pancreatic β cells, and describes some key questions regarding their importance to β cells.
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Affiliation(s)
| | - Roland Stein
- Correspondence: 723 Light Hall, 2215 Garland Ave Nashville, TN 37232 Phone: 615-322-7026 Facsimile: 615-322-7236
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Chen L, Wang Q, Zhang L, Tai J, Wang H, Li W, Li X, He W, Li X. A novel paradigm for potential drug-targets discovery: quantifying relationships of enzymes and cascade interactions of neighboring biological processes to identify drug-targets. MOLECULAR BIOSYSTEMS 2011; 7:1033-41. [PMID: 21270979 DOI: 10.1039/c0mb00249f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Target discovery is the most crucial step in a modern drug discovery development. Our objective in this study is to propose a novel paradigm for a better discrimination of drug-targets and non-drug-targets with minimum disruptive side-effects under a biological pathway context. We introduce a novel metric, namely, "pathway closeness centrality", for each gene that jointly considers the relationships of its neighboring enzymes and cross-talks of biological processes, to evaluate its probability of being a drug-target. This metric could distinguish drug-targets with non-drug-targets. Genes with lower pathway closeness centrality values are prone to play marginal roles in biological processes and have less lethality risk, but appear to have tissue-specific expressions. Compared with traditional metrics, our method outperforms degree, betweenness and bridging centrality under the human pathway context. Analysis of the existing top 20 drugs with the most disruptive side-effects indicates that pathway closeness centrality is an appropriate index to predict the probability of the occurrence of adverse pharmacological effects. Case studies in prostate cancer and type 2 diabetes mellitus indicate that the pathway closeness centrality metric could distinguish likely drug-targets well from human pathways. Thus, our method is a promising tool to aid target identification in drug discovery.
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Affiliation(s)
- Lina Chen
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Hei Longjiang Province, China.
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Kanai K, Aramata S, Katakami S, Yasuda K, Kataoka K. Proteasome activator PA28{gamma} stimulates degradation of GSK3-phosphorylated insulin transcription activator MAFA. J Mol Endocrinol 2011; 47:119-27. [PMID: 21646385 DOI: 10.1530/jme-11-0044] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
MAFA is a member of the MAF family of basic leucine zipper transcription factors and is a critical regulator of insulin gene expression and islet β-cell function. To be degraded by the proteasome, MAFA must be phosphorylated by GSK3 and MAP kinases at multiple serine and threonine residues (Ser49, Thr53, Thr57, Ser61, and Ser65) within its amino-terminal domain. In this study, we report that MAFA degradation is stimulated by PA28γ (REGγ and PSME3), a member of a family of proteasome activators that bind and activate the 20S proteasome. To date, only a few PA28γ-proteasome pathway substrates have been identified, including steroid receptor coactivator 3 (SRC3) and the cell cycle inhibitor p21 (CIP1). PA28γ binds to MAFA, induces its proteasomal degradation, and thereby attenuates MAFA-driven transcriptional activation of the insulin promoter. Co-expression of GSK3 enhanced the PA28γ-mediated degradation of MAFA, but mutants that contained alanine substitutions at the MAFA phosphorylation sites did not bind PA28γ and were resistant to degradation. We also found that a PA28γ mutant (N151Y) that did not stimulate p21 degradation enhanced MAFA degradation, and another mutant (K188D) that promoted greater p21 degradation did not enhance MAFA degradation. These results suggest that PA28γ stimulates MAFA degradation through a novel molecular mechanism that is distinct from that for the degradation of p21.
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Affiliation(s)
- Kenichi Kanai
- Laboratory of Molecular and Developmental Biology, Graduate School of Biological Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
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