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Pancreatic islet

Xin-Xin Yu, Wei-Lin Qiu, Liu Yang, Lin-Chen Li, Yu-Wei Zhang, Cheng-Ran Xu
Pancreatic endocrine lineages are derived from pancreatic progenitors that undergo a cell fate transition requiring a switch from low to high Ngn3 expression. However, the underlying chromatin regulatory mechanisms are unclear. Here, we performed epigenomic analysis of gene regulatory loci featuring histone marks in cells with low or high level of Ngn3 expression. In combination with transcriptomic analysis, we discovered that in Ngn3-high cells, the removal of H3K27me3 was associated with the activation of key transcription factors and the establishment of primed and active enhancers...
March 20, 2018: Development
Mariana Carla Mendes, Maria Lúcia Bonfleur, Rosane Aparecida Ribeiro, Camila Lubaczeuski, Ana Flavia Justino Fêo, Rodrigo Vargas, Everardo Magalhães Carneiro, Antonio Carlos Boschero, Allan Cezar Faria Araujo, Sandra Lucinei Balbo
PURPOSE: Duodeno-jejunal bypass (DJB) operation improves glucose homeostasis in morbid obesity, independently of weight loss or reductions in adiposity, through mechanisms not yet fully elucidated. Herein, we evaluated the effects of DJB upon glucose homeostasis, endocrine pancreatic morphology, and β-cell responsiveness to potentiating agents of cholinergic and cAMP pathways, in western diet (WD) obese rats, at 2 months after operation. METHODS: From 8 to 18 weeks of age male Wistar rats fed on a WD...
March 19, 2018: Endocrine
Patricia Cristine Borck, Jean Franciesco Vettorazzi, Renato Chaves Souto Branco, Thiago Martins Batista, Junia Carolina Santos-Silva, Vanessa Yumi Nakanishi, Antonio Carlos Boschero, Rosane Aparecida Ribeiro, Everardo Magalhães Carneiro
The sulfur-containing amino acid, taurine (Tau), regulates glucose and lipid homeostasis under normal, pre- and diabetic conditions. Here, we aimed to verify whether Tau supplementation exerts its beneficial effects against obesity, hyperglycemia and alterations in islet functions, in leptin-deficient obese (ob/ob), over a long period of treatment. From weaning until 12 months of age, female ob/ob mice received, or not, 5% Tau in drinking water (obTau group). After this period, a reduction in hypertriglyceridemia and an improvement in glucose tolerance and insulin sensitivity were observed in obTau mice...
March 19, 2018: Amino Acids
Dandan Zhao, Shaoqian Zhao, Xiao Wang, Mingbo Su, Wen Liu, Qinyun Ma, Jie Hong, Weiqiong Gu, Jingya Li, Ruixin Liu, Guang Ning, Jiqiu Wang, Yifei Zhang
The clinical application of dipeptidyl peptidase IV inhibitors (DPP4i) increasing active glucagon-like peptide-1 (AGLP-1) levels has been linked to pancreatitis, pancreatic tumors, and cardiovascular events. However, DPP4 mutations in humans or the long-term outcomes of high glucagon-like peptide-1 (GLP-1) level exposure have not been reported. A trio family with a proband showing an extremely high AGLP-1 level [defined here as hyperglipemia (hyper-glucagon-like peptide-1-emia)] were conducted whole-exome sequencing for potential pathogenic genetic defects...
2018: Frontiers in Endocrinology
Monia Cito, Silvia Pellegrini, Lorenzo Piemonti, Valeria Sordi
The experience in the field of islet transplantation shows that it is possible to replace β cells in a patient with type 1 diabetes (T1D), but this cell therapy is limited by the scarcity of organ donors and by the danger associated to the immunosuppressive drugs. Stem cell therapy is becoming a concrete opportunity to treat various diseases. In particular, for a disease like T1D, caused by the loss of a single specific cell type that does not need to be transplanted back in its originating site to perform its function, a stem cell-based cell replacement therapy seems to be the ideal cure...
March 2018: Endocrine Connections
Michele F M Sciacca, Rosa Chillemi, Sebastiano Sciuto, Valentina Greco, Concetta Messineo, Samuel A Kotler, Dong-Kuk Lee, Jeffrey R Brender, Ayyalusamy Ramamoorthy, Carmelo La Rosa, Danilo Milardi
Type II diabetes mellitus (T2DM) is characterized by the presence of amyloid deposits of the human islet amyloid polypeptide (hIAPP) in pancreatic β-cells. A wealth of data supports the hypothesis that hIAPP's toxicity is related to an abnormal interaction of amyloids with islet cell membranes. Thus, many studies aimed at finding effective therapies for T2DM focus on the design of molecules that are able to inhibit hIAPP's amyloid growth and the related membrane damage as well. Based on this view and inspired by its known anti-amyloid properties, we have functionalized resveratrol with a phosphoryl moiety (4'-O-PR) that improves its solubility and pharmacological properties...
March 16, 2018: Biochimica et Biophysica Acta
Jacqueline H Parilla, Rebecca L Hull, Sakeneh Zraika
Neprilysin (NEP) is an endopeptidase known to modulate nervous, cardiovascular, and immune systems via inactivation of regulatory peptides. In addition, it may also contribute to impaired glucose homeostasis as observed in type 2 diabetes (T2D). Specifically, we and others have shown that NEP is upregulated under conditions associated with T2D, whereas NEP deficiency and/or inhibition improves glucose homeostasis via enhanced glucose tolerance, insulin sensitivity, and pancreatic β-cell function. Whether increased β-cell mass also occurs with lack of NEP activity is unknown...
March 1, 2018: Journal of Histochemistry and Cytochemistry: Official Journal of the Histochemistry Society
M Sassek, E Pruszynska-Oszmalek, K W Nowak
The physiology of porcine pancreatic islets is poorly understood. Orexin A is one of important agents regulating the physiology of porcine pancreatic islets. This study aimed to determine the potential effect of orexin A on the functioning of porcine pancreatic islets. Orexin receptor localization was done by PCR (polymerase chain reaction) and Western Blot, both in pancreatic isolated islets and whole pancreas. Secretion of insulin and glucagon from islets after orexin-A treatment was assayed. The viability of pig pancreatic islet cells and level of cleaved/total caspase 3 protein were measured by MTT test (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and Western blotting, respectively...
December 2017: Journal of Physiology and Pharmacology: An Official Journal of the Polish Physiological Society
Vishal Musale, Yasser H A Abdel-Wahab, Peter R Flatt, J Michael Conlon, Maria Luisa Mangoni
Long-standing Type 2 diabetes is associated with loss of both β-cell function and β-cell mass. Peptides derived from the frog-skin host-defense peptide esculentin-1 have been shown to exhibit potent, broad-spectrum antimicrobial activity. The aim of the present study is to determine whether such peptides also show insulinotropic and β-cell protective activities. Esculentin-1a(1-21).NH2 , esculentin-1b(1-18).NH2 , and esculentin-1a(1-14).NH2 produced concentration-dependent stimulations of insulin release from BRIN-BD11 rat clonal β-cells, 1...
March 17, 2018: Amino Acids
Dafna Greitzer-Antes, Li Xie, Tairan Qin, Huanli Xie, Dan Zhu, Subhankar Dolai, Tao Liang, Fei Kang, Alexandre B Hardy, Yan He, Youhou Kang, Herbert Y Gaisano
The voltage-dependent K+ (Kv) channel Kv2.1 is a major delayed rectifier in many secretory cells, including pancreatic β-cells. In addition, Kv2.1 has a direct role in exocytosis at an undefined step, involving SNARE proteins and independent of its ion-conducting pore function. Here, we elucidated the precise step in exocytosis. We previously reported that syntaxin 3 (Syn-3) is the key syntaxin that mediates exocytosis of newcomer secretory granules that spend minimal residence time on the plasma membrane before fusion...
March 16, 2018: Journal of Biological Chemistry
Jitka Rybová, Ladislav Kuchar, Helena Hulková, Befekadu Asfaw, Robert Dobrovolný, Jakub Sikora, Vladimír Havlícek, Ludovít Škultéty, Jana Ledvinová
Blood group B glycosphingolipids (B-GSLs) are substrates of the lysosomal alpha-galactosidase A (AGAL). Similar to its major substrate - globotriaosylceramide (Gb3Cer) - B-GSLs are not degraded and accumulate in the cells of patients affected by an inherited defect of AGAL activity (Fabry disease - FD).The pancreas is a secretory organ known to have high biosynthesis of blood group GSLs. Herein, we provide a comprehensive overview of the biochemical and structural abnormalities in pancreatic tissue from two male FD patients with blood group B...
March 14, 2018: Glycobiology
Katarzyna Skrzypek, Yazmin Brito Barrera, Thomas Groth, Dimitrios Stamatialis
INTRODUCTION: Encapsulation of pancreatic islets or beta cells is a promising strategy for treatment of type 1 diabetes by providing an immune isolated environment and allowing for transplantation in a different location than the liver. However, islets used for encapsulation often show lower functionality due to the damaging of islet endothelial cells during the isolation procedure. Factors produced by endothelial cells have great impact on beta cell insulin secretion. Therefore, mutual signaling between endothelial cells and beta cells should be considered for the development of encapsulation systems to achieve high insulin secretion and maintain beta cell viability...
March 2018: International Journal of Artificial Organs
Lianbin Xu, Xueyan Lin, Robin R White, Mark D Hanigan, Zhiyong Hu, Qiuling Hou, Yun Wang, Zhonghua Wang
Background: Circulating amino acid (AA) and nitric oxide (NO) concentrations and hepatic gluconeogenesis are affected by previous protein intake. However, information about their relations and islet hormone responses is limited. Objective: This study investigated the associations between islet hormone concentrations with circulating AA and NO concentrations as well as with hepatic gluconeogenesis in lactating rats. Methods: At delivery, 18 Wistar rats aged 14 wk were assigned either to low-protein (LP; 9% protein), standard-protein (SP; 21% protein), or high-protein (HP; 35% protein) diets for 15 d in groups of 6 pups/dam...
March 1, 2018: Journal of Nutrition
Meng-Lin Liu, Meng-Long Wang, Jing-Jun Lv, Jie Wei, Jun Wan
Adriamycin (ADR) is a chemotherapeutic drug used to treat tumors in a clinical setting. However, its use is limited by a side effect of cardiotoxicity. Glibenclamide (Gli), an inhibitor of mitochondrial ATP-dependent potassium (K-ATP) channels, blocks the cardioprotective effects of mitochondrial K-ATP channel openers and induces apoptosis in rodent pancreatic islet β-cell lines. However, little is known about the role of Gli in ADR-induced cardiotoxicity. The present study was designed to investigate the impact of Gli on ADR-induced cardiotoxicity in rats...
April 2018: Experimental and Therapeutic Medicine
Anthony J Kee, Jayshan Chagan, Jeng Yie Chan, Nicole S Bryce, Christine A Lucas, Jun Zeng, Jeff Hook, Herbert Treutlein, D Ross Laybutt, Justine R Stehn, Peter W Gunning, Edna C Hardeman
The development of novel small molecule inhibitors of the cancer-associated tropomyosin 3.1 (Tpm3.1) provides the ability to examine the metabolic function of specific actin filament populations. We have determined the ability of these anti-Tpm (ATM) compounds to regulate glucose metabolism in mice. Acute treatment (1 h) of wild-type (WT) mice with the compounds (TR100 and ATM1001) led to a decrease in glucose clearance due mainly to suppression of glucose-stimulated insulin secretion (GSIS) from the pancreatic islets...
March 15, 2018: Scientific Reports
Naoyuki Kitao, Akinobu Nakamura, Hideaki Miyoshi, Hiroshi Nomoto, Kiyohiko Takahashi, Kazuno Omori, Kohei Yamamoto, Kyu Yong Cho, Yasuo Terauchi, Tatsuya Atsumi
OBJECTIVE: We investigated whether glucokinase and insulin receptor substrate-2 were required for beta cell proliferation induced by short-term high-fat (HF) diet feeding, as has been shown for long-term HF diet. METHODS: Eight-week-old C57BL/6 J mice were exposed to either a standard chow (SC) or HF diet. After 1 week on the diet, histopathological beta cell proliferation and gene expression in isolated islets were examined. Additionally, 8-week-old beta cell-specific glucokinase haploinsufficient (Gck+/- ) and Irs2 knockout (Irs2-/- ) mice were exposed to either an SC or HF diet...
March 12, 2018: Metabolism: Clinical and Experimental
Aurore Quinault, Corinne Leloup, Geoffrey Denwood, Coralie Spiegelhalter, Marianne Rodriguez, Philippe Lefebvre, Nadia Messaddeq, Quan Zhang, Catherine Dacquet, Luc Pénicaud, Stephan C Collins
The rhythmic nature of insulin secretion over the 24h cycle in pancreatic islets has been mostly investigated using transcriptomics studies showing that modulation of insulin secretion over this cycle is achieved via distal stages of insulin secretion. We set out to measure β-cell exocytosis using in depth cell physiology techniques at several time points. In agreement with the activity and feeding pattern of nocturnal rodents, we find that C57/Bl6J islets in culture for 24h exhibit higher insulin secretion during the corresponding dark phase than in the light phase (Zeitgeber Time ZT20 and ZT8, respectively, in vivo)...
2018: PloS One
Kapo Saukkonen, Jaana Hagström, Harri Mustonen, Laura Lehtinen, Olli Carpen, Leif C Andersson, Hanna Seppänen, Caj Haglund
Expression of regenerating islet-derived protein 4 (REG4), a secretory protein involved in cell differentiation and proliferation, is upregulated in inflammatory bowel diseases and in many gastrointestinal malignancies. The prognostic significance of its expression in pancreatic ductal adenocarcinoma is unknown. Our aim was to investigate tumor tissue and serum REG4 expression in pancreatic ductal adenocarcinoma patients. We also evaluated as a control the diagnostic value of serum REG4 level in patients with chronic pancreatitis...
March 2018: Tumour Biology: the Journal of the International Society for Oncodevelopmental Biology and Medicine
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
Zai Wang, Liang Peng, Yu-Li Song, Shiqing Xu, Zhan Hua, Ni Fang, Min Zhai, Honglin Liu, Qing Fang, Tingting Deng, Wenjian Zhang, Yuan-Jia Chen, Jinning Lou
Aberrant blood vessel formation and hemorrhage may contribute to tumor progression and are potential targets in the treatment of several types of cancer. Pancreatic neuroendocrine tumors (PNETs) are highly vascularized, particularly when they are well-differentiated. However, the process of vascularization and endothelial cell detachment in PNETs is poorly understood. In the present study, 132 PNET clinical samples were examined and a special type of hemorrhagic region was observed in ~30% of the samples regardless of tumor subtype...
April 2018: Oncology Letters
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