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Abraham Neelankal John, Ramesh Ram, Fang-Xu Jiang
Type 2 diabetes (T2D) is a global health issue and dedifferentiation plays underlying causes in the pathophysiology of T2D; however, there is a lack of understanding in the mechanism. Dedifferentiation results from the loss of function of pancreatic β-cells alongside a reduction in essential transcription factors under various physiological stressors. Our study aimed to establish db/db as an animal model for dedifferentiation by using RNA sequencing to compare the gene expression profile in islets isolated from wild-type, db/+ and db/db mice, and qPCR was performed to validate those significant genes...
March 14, 2018: Endocrine Pathology
Ning Wang, Yanan Zhu, Min Xie, Lintao Wang, Feiyan Jin, Yihui Li, Qingxin Yuan, Wei De
BACKGROUND/AIMS: The main pathogenic mechanism of diabetes is a decrease in the number of islet beta cells or a decline in their function. Recent studies have shown that pancreatic long noncoding RNAs (lncRNAs) have a high degree of tissue specificity and may be involved in the maintenance of islet cells function and the development of diabetes. The aim of this study was to investigate the molecular regulatory mechanism of mouse maternal expressed gene 3 (Meg3) in insulin biosynthesis in pancreatic islets...
March 6, 2018: Cellular Physiology and Biochemistry
Mahmoud Hashemi Tabar, Mohammad Reza Tabandeh, Eskandar Moghimipour, Dian Dayer, Ata A Ghadiri, Elham Allah Bakhshi, Mahmoud Orazizadeh, Mohammad Ali Ghafari
Pancreatic and duodenal homeobox 1 (Pdx1) and Sonic hedgehog (Shh) are the key regulators of beta-cell function. In vitro experiments have shown that there is significant cooperation between Pdx1 and Shh with regard to the production and maintenance of insulin-producing cells (IPCs). In this study, the combined effect of Pdx1 overexpression and Shh manipulation on the function of adipose tissue-derived IPCs was determined. A eukaryotic expression vector ( Pdx1- pCDNA3.1(+)) was constructed and transfected into a Chinese hamster ovary (CHO) cell line...
March 2018: FEBS Open Bio
Thomas Robert, Ines De Mesmaeker, Geert M Stangé, Krista G Suenens, Zhidong Ling, Evert J Kroon, Daniel G Pipeleers
Human stem cells represent a potential source for implants that replace the depleted functional beta cell mass (FBM) in diabetes patients. Human embryonic stem cell-derived pancreatic endoderm (hES-PE) can generate implants with glucose-responsive beta cells capable of reducing hyperglycemia in mice. This study with device-encapsulated hES-PE (4 × 106 cells/mouse) determines the biologic characteristics at which implants establish metabolic control during a 50-week follow-up. A metabolically adequate FBM was achieved by (1) formation of a sufficient beta cell number (>0...
February 22, 2018: Stem Cell Reports
Eiji Yamato
OBJECTIVE: Histone deacytylase inhibitors (HDACis) inhibit the deacetylation of the lysine residue of proteins, including histones, and regulate the transcription of a variety of genes. Recently, HDACis have been used clinically as anti-cancer drugs and possible anti-diabetic drugs. Even though HDACis have been proven to protect the cytokine-induced damage of pancreatic beta cells, evidence also shows that high doses of HDACis are cytotoxic. In the present study, we, therefore, investigated the eff ect of HDACis on insulin secretion in a pancreatic beta cell line...
January 1, 2018: Endocrine Regulations
Jose M Mellado-Gil, Esther Fuente-Martín, Petra I Lorenzo, Nadia Cobo-Vuilleumier, Livia López-Noriega, Alejandro Martín-Montalvo, Irene de Gracia Herrera Gómez, Maria Ceballos-Chávez, Laura Gómez-Jaramillo, Antonio Campos-Caro, Silvana Y Romero-Zerbo, Júlia Rodríguez-Comas, Joan-Marc Servitja, Gemma Rojo-Martinez, Abdelkrim Hmadcha, Bernat Soria, Marco Bugliani, Piero Marchetti, Francisco J Bérmudez-Silva, Jose C Reyes, Manuel Aguilar-Diosdado, Benoit R Gauthier
HMG20A (also known as iBRAF) is a chromatin factor involved in neuronal differentiation and maturation. Recently small nucleotide polymorphisms (SNPs) in the HMG20A gene have been linked to type 2 diabetes mellitus (T2DM) yet neither expression nor function of this T2DM candidate gene in islets is known. Herein we demonstrate that HMG20A is expressed in both human and mouse islets and that levels are decreased in islets of T2DM donors as compared to islets from non-diabetic donors. In vitro studies in mouse and human islets demonstrated that glucose transiently increased HMG20A transcript levels, a result also observed in islets of gestating mice...
February 15, 2018: Cell Death & Disease
Abhay Srivastava, Nidheesh Dadheech, Mitul Vakani, Sarita Gupta
In the present study, Swertisin's role in triggering resident pancreatic progenitors for islet neogenesis in Streptozotocin (STZ) diabetic mice was explored. STZ diabetic mice when treated with Swertisin demonstrated reversion to normoglycemia and significant elevation of fasting serum insulin levels. On screening the pancreatic tissue post Swertisin treatment in the STZ diabetic mice, we observed significant up-regulation of key transcription factors viz. Pdx1, Neurog3, MafA and Nkx6.1 required for islet neogenesis and beta cell homeostasis...
February 8, 2018: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Abraham Neelankal John, Fang-Xu Jiang
One significant health issue that plagues contemporary society is that of Type 2 diabetes (T2D). This disease is characterised by higher-than-average blood glucose levels as a result of a combination of insulin resistance and insufficient insulin secretions from the β-cells of pancreatic islets of Langerhans. Previous developmental research into the pancreas has identified how early precursor genes of pancreatic β-cells, such as Cpal, Ngn3, NeuroD, Ptf1a, and cMyc, play an essential role in the differentiation of these cells...
December 14, 2017: Journal of Diabetes and its Complications
Peter A Kropp, Jennifer C Dunn, Bethany A Carboneau, Doris A Stoffers, Maureen Gannon
The transcription factors Pdx1 and Oc1 are co-expressed in multipotent pancreatic progenitors (MPCs), but their expression patterns diverge in hormone-expressing cells, with Oc1 expression being extinguished in the endocrine lineage and Pdx1 being maintained at high levels in β cells. We previously demonstrated that cooperative function of these two factors in MPCs is necessary for proper specification and differentiation of pancreatic endocrine cells. In those studies, we observed a persistent decrease in expression of the β-cell maturity factor MafA...
December 12, 2017: American Journal of Physiology. Endocrinology and Metabolism
Ryo Iwaoka, Kohsuke Kataoka
Insulin mRNA expression in pancreatic islet β-cells is upregulated by extracellular glucose concentration, but the underlying mechanism remains incompletely understood. MafA is a transcriptional activator specifically enriched in β-cells that binds to the insulin gene promoter. Its expression is transcriptionally and post-transcriptionally regulated by glucose. Moreover, AMP-activated protein kinase (AMPK), a regulator of cellular energy homeostasis, is inhibited by high glucose, and this inhibition is essential for the up-regulation of insulin gene expression and glucose-stimulated insulin secretion (GSIS)...
January 18, 2018: Journal of Biological Chemistry
Donato Iacovazzo, Sarah E Flanagan, Emily Walker, Rosana Quezado, Fernando Antonio de Sousa Barros, Richard Caswell, Matthew B Johnson, Matthew Wakeling, Michael Brändle, Min Guo, Mary N Dang, Plamena Gabrovska, Bruno Niederle, Emanuel Christ, Stefan Jenni, Bence Sipos, Maike Nieser, Andrea Frilling, Ketan Dhatariya, Philippe Chanson, Wouter W de Herder, Björn Konukiewitz, Günter Klöppel, Roland Stein, Márta Korbonits, Sian Ellard
The β-cell-enriched MAFA transcription factor plays a central role in regulating glucose-stimulated insulin secretion while also demonstrating oncogenic transformation potential in vitro. No disease-causing MAFA variants have been previously described. We investigated a large pedigree with autosomal dominant inheritance of diabetes mellitus or insulinomatosis, an adult-onset condition of recurrent hyperinsulinemic hypoglycemia caused by multiple insulin-secreting neuroendocrine tumors of the pancreas. Using exome sequencing, we identified a missense MAFA mutation (p...
January 30, 2018: Proceedings of the National Academy of Sciences of the United States of America
Hossam H Shawki, Hisashi Oishi, Toshiaki Usui, Yu Kitadate, Walaa A Basha, Ahmed M Abdellatif, Kazunori Hasegawa, Risa Okada, Keiji Mochida, Hany A El-Shemy, Masafumi Muratani, Atsuo Ogura, Shosei Yoshida, Satoru Takahashi
The transcription factor MAFB is an important regulator of the development and differentiation of various organs and tissues. Previous studies have shown that MAFB is expressed in embryonic and adult mouse testes and is expected to act as the downstream target of retinoic acid (RA) to initiate spermatogenesis. However, its exact localization and function remain unclear. Here, we localized MAFB expression in embryonic and adult testes and analyzed its gene function using Mafb-deficient mice. We found that MAFB and c-MAF are the only large MAF transcription factors expressed in testes, while MAFA and NRL are not...
2018: PloS One
Xiangwei Xiao, Ping Guo, Chiyo Shiota, Ting Zhang, Gina M Coudriet, Shane Fischbach, Krishna Prasadan, Joseph Fusco, Sabarinathan Ramachandran, Piotr Witkowski, Jon D Piganelli, George K Gittes
Successful strategies for treating type 1 diabetes need to restore the function of pancreatic beta cells that are destroyed by the immune system and overcome further destruction of insulin-producing cells. Here, we infused adeno-associated virus carrying Pdx1 and MafA expression cassettes through the pancreatic duct to reprogram alpha cells into functional beta cells and normalized blood glucose in both beta cell-toxin-induced diabetic mice and in autoimmune non-obese diabetic (NOD) mice. The euglycemia in toxin-induced diabetic mice and new insulin+ cells persisted in the autoimmune NOD mice for 4 months prior to reestablishment of autoimmune diabetes...
January 4, 2018: Cell Stem Cell
Anna B Osipovich, Mark A Magnuson
Beta cell replacement strategies hold promise for permanently treating type 1 diabetes. In Cell Stem Cell, Xiao et al. (2018) restore pancreatic beta cell mass and normalize blood glucose in diabetic mice by reprogramming pancreatic alpha to beta cells using Pdx1- and Mafa-expressing adeno-associated virus infused into the pancreatic duct.
January 4, 2018: Cell Stem Cell
Feiyan Jin, Ning Wang, Yanan Zhu, Lianghui You, Lintao Wang, Wei De, Wei Tang
BACKGROUND: Evidence shows that long non-coding RNAs (lncRNAs) are involved in individual development, cell differentiation, cell cycle processes and other important life processes and are closely related to major human diseases, including diabetes. Recent studies have reported that lncRNAs are involved in β cell functions and that lncRNA Gas5 levels decreased in T2DM patients' serum. The purpose of this study was to clarify the role of lncRNA Gas5 in mouse β cell functions in vitro and in vivo...
October 23, 2017: Cellular Physiology and Biochemistry
Yunshin Jung, Ruyi Zhou, Toshiki Kato, Jeffrey K Usui, Masafumi Muratani, Hisashi Oishi, Margarete M S Heck, Satoru Takahashi
Adenoviral gene transfer of key β cell developmental regulators including Pdx1, Neurod1, and Mafa (PDA) has been reported to generate insulin-producing cells in the liver. However, PDA insulin secretion is transient and glucose unresponsive. Here, we report that an additional β cell developmental regulator, insulin gene enhancer binding protein splicing variant (Isl1β), improved insulin production and glucose-responsive secretion in PDA mice. Microarray gene expression analysis suggested that adenoviral PDA transfer required an additional element for mature β cell generation, such as Isl1 and Elf3 in the liver...
February 1, 2018: Endocrinology
Aleksandra Hecel, Joanna Wątły, Magdalena Rowińska-Żyrek, Jolanta Świątek-Kozłowska, Henryk Kozłowski
Consecutive histidine repeats are chosen both by nature and by molecular biologists due to their high affinity towards metal ions. Screening of the human genome showed that transcription factors are extremely rich in His tracts. In this work, we examine two of such His-rich regions from forkhead box and MAFA proteins-MB3 (contains 18 His) and MB6 (with 21 His residues), focusing on the affinity and binding modes of Cu2+ and Zn2+ towards the two His-rich regions. In the case of Zn2+ species, the availability of imidazole nitrogen donors enhances metal complex stability...
January 2018: Journal of Biological Inorganic Chemistry: JBIC
Diana Ribeiro, Eva-Marie Andersson, Nikki Heath, Anette Persson-Kry, Richard Collins, Ryan Hicks, Niek Dekker, Anna Forslöw
It has been suggested that extracellular vesicles (EVs) can mediate crosstalk between hormones and metabolites within pancreatic tissue. However, the possible effect of pancreatic EVs on stem cell differentiation into pancreatic lineages remains unknown. Herein, human islet-derived EVs (h-Islet-EVs) were isolated, characterized and subsequently added to human induced pluripotent stem cell (iPSC) clusters during pancreatic differentiation. The h-islet-EVs had a mean size of 117±7 nm and showed positive expression of CD63 and CD81 EV markers as measured by ELISA...
2017: PloS One
Yaxi Zhu, Qian Liu, Zhiguang Zhou, Yasuhiro Ikeda
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...
November 2, 2017: Stem Cell Research & Therapy
Ilaria Marzinotto, Silvia Pellegrini, Cristina Brigatti, Rita Nano, Raffaella Melzi, Alessia Mercalli, Daniela Liberati, Valeria Sordi, Maurizio Ferrari, Massimo Falconi, Claudio Doglioni, Philippe Ravassard, Lorenzo Piemonti, Vito Lampasona
miR-204 has been proposed to modulate insulin expression in human pancreatic islets by regulating the expression of the MAFA transcript, and in turn insulin transcription. We investigated miR-204 expression in pancreatic endocrine tumors (PET), a panel of human tissues, tissues derived from pancreatic islet purification, and in induced pluripotent stem cells (iPSCs) differentiated towards a pancreatic endocrine phenotype by quantitative real time RT-PCR or droplet digital PCR (ddPCR). In addition, we evaluated the effect of miR-204 up- or down-regulation in purified human islets and in the EndoC-βH1 cell line, as an experimental model of human pancreatic β cells...
October 25, 2017: Scientific Reports
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