scholarly journals Pancreatic β-Cell Senescence: Mechanisms and Association with Diabetes

2021 ◽  
pp. 59-72
Author(s):  
Sara M Ahmed ◽  
Shimaa E Elshenawy ◽  
Sara Sedky ◽  
Ahmed O Elmehrath ◽  
Nagwa El-Badri
Keyword(s):  
Cell Cycle ◽  
Cellular Response ◽  
Cell Mass ◽  
Cell Senescence ◽  
Continuous Exposure ◽  
Cell Cycle Regulators ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Repair Mechanisms ◽  
Cell Cycle Inhibitors

Senescence occurs as a part of the cellular response to different stressors. With increasing age, continuous exposure to stressors leads to age-induced senescence. Pancreatic β-cell proliferation and glucose homeostasis also decrease with age, which results in a decrease in β cell mass and, eventually, the possible development of diabetes. This process is mediated through impaired cell cycle regulators, along with specific increases in cell cycle inhibitors, telomere shortening, and defective DNA repair mechanisms. Diabetes contributes to β-cell senescence through hyperglycaemia, dyslipidaemia, oxidative stress, and inflammation. β cells isolated from patients with Type 2 diabetes mellitus have been shown to have senescence markers, such as senescence-associated secretory phenotype genes and β-galactosidase. In this paper, the authors discuss the mechanisms of cellular senescence, how senescence is impacted by the diabetic microenvironment, and the possible mechanisms and factors contributing to β-cell senescence.

scholarly journals Role of AKT/mTORC1 pathway in pancreatic β-cell proliferation

2012 ◽  
pp. 235-243 ◽  
Author(s):  
Norman Balcazar Morales ◽  
Cecilia Aguilar de Plata
Keyword(s):  
Cell Cycle ◽  
Growth Factors ◽  
Cell Cycle Progression ◽  
Cell Mass ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Cycle Progression ◽  
Mtorc1 Signaling

Growth factors, insulin signaling and nutrients are important regulators of β-cell mass and function. The events linking these signals to regulation of β-cell mass are not completely understood. Recent findings indicate that mTOR pathway integrates signals from growth factors and nutrients with transcription, translation, cell size, cytoskeleton remodeling and mitochondrial metabolism. mTOR is a part of two distinct complexes; mTORC1 and mTORC2. The mammalian TORC1 is sensitive to rapamycin and contains Raptor, deptor, PRAS40 and the G protein β-subunit-like protein (GβL). mTORC1 activates key regulators of protein translation; ribosomal S6 kinase (S6K) and eukaryote initiation factor 4E-binding protein 1. This review summarizes current findings about the role of AKT/mTORC1 signaling in regulation of pancreatic β cell mass and proliferation. mTORC1 is a major regulator of β-cell cycle progression by modulation of cyclins D2, D3 and cdk4/cyclin D activity. These studies uncovered key novel pathways controlling cell cycle progression in β-cells in vivo. This information can be used to develop alternative approaches to expand β-cell mass in vivo and in vitro without the risk of oncogenic transformation. The acquisition of such knowledge is critical for the design of improved therapeutic strategies for the treatment and cure of diabetes as well as to understand the effects of mTOR inhibitors in β-cell function.

Ileal Transposition Increases Pancreatic β Cell Mass and Decreases β Cell Senescence in Diet-Induced Obese Rats

2020 ◽  
Vol 30 (5) ◽  
pp. 1849-1858 ◽  
Author(s):  
Chang Ho Ahn ◽  
Eun Hye Choi ◽  
Tae Jung Oh ◽  
Young Min Cho
Keyword(s):  
Cell Mass ◽  
Cell Senescence ◽  
Pancreatic Β Cell ◽  
Ileal Transposition ◽  
Β Cell ◽  
Obese Rats

scholarly journals Ontology of the apelinergic system in mouse pancreas during pregnancy and relationship with β-cell mass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brenda Strutt ◽  
Sandra Szlapinski ◽  
Thineesha Gnaneswaran ◽  
Sarah Donegan ◽  
Jessica Hill ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Insulin Secretion ◽  
Glucose Transporter ◽  
Cell Mass ◽  
Elevated Serum ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Glucose Transporter 2 ◽  
Glucose Stimulated Insulin Secretion

AbstractThe apelin receptor (Aplnr) and its ligands, Apelin and Apela, contribute to metabolic control. The insulin resistance associated with pregnancy is accommodated by an expansion of pancreatic β-cell mass (BCM) and increased insulin secretion, involving the proliferation of insulin-expressing, glucose transporter 2-low (Ins+Glut2LO) progenitor cells. We examined changes in the apelinergic system during normal mouse pregnancy and in pregnancies complicated by glucose intolerance with reduced BCM. Expression of Aplnr, Apelin and Apela was quantified in Ins+Glut2LO cells isolated from mouse pancreata and found to be significantly higher than in mature β-cells by DNA microarray and qPCR. Apelin was localized to most β-cells by immunohistochemistry although Aplnr was predominantly associated with Ins+Glut2LO cells. Aplnr-staining cells increased three- to four-fold during pregnancy being maximal at gestational days (GD) 9–12 but were significantly reduced in glucose intolerant mice. Apelin-13 increased β-cell proliferation in isolated mouse islets and INS1E cells, but not glucose-stimulated insulin secretion. Glucose intolerant pregnant mice had significantly elevated serum Apelin levels at GD 9 associated with an increased presence of placental IL-6. Placental expression of the apelinergic axis remained unaltered, however. Results show that the apelinergic system is highly expressed in pancreatic β-cell progenitors and may contribute to β-cell proliferation in pregnancy.

Imaging of pancreatic β-cell mass by PET

2012 ◽  
Vol 2 (2) ◽  
pp. 111-118
Author(s):  
Gary W Cline
Keyword(s):  
Cell Mass ◽  
Pancreatic Β Cell ◽  
Β Cell

scholarly journals Programming effects of metformin exposure during gestation on offspring pancreatic β‐cell mass and glucose homeostasis (910.5)

2014 ◽  
Vol 28 (S1) ◽  
Author(s):  
Brigid Gregg ◽  
Emilyn Alejandro ◽  
Michelle Smith ◽  
Lynda Elghazi ◽  
Deena El‐Gabri ◽  
...  
Keyword(s):  
Glucose Homeostasis ◽  
Cell Mass ◽  
Pancreatic Β Cell ◽  
Β Cell

scholarly journals Automated quantification of pancreatic β-cell mass

2014 ◽  
Vol 306 (12) ◽  
pp. E1460-E1467 ◽  
Author(s):  
Maria L. Golson ◽  
William S. Bush ◽  
Marcela Brissova
Keyword(s):  
High Resolution ◽  
Mass Measurement ◽  
Virtual Slide ◽  
Cell Mass ◽  
Automated Analysis ◽  
Systematic Sampling ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Cell Hyperplasia ◽  
Time Required

β-Cell mass is a parameter commonly measured in studies of islet biology and diabetes. However, the rigorous quantification of pancreatic β-cell mass using conventional histological methods is a time-consuming process. Rapidly evolving virtual slide technology with high-resolution slide scanners and newly developed image analysis tools has the potential to transform β-cell mass measurement. To test the effectiveness and accuracy of this new approach, we assessed pancreata from normal C57Bl/6J mice and from mouse models of β-cell ablation (streptozotocin-treated mice) and β-cell hyperplasia (leptin-deficient mice), using a standardized systematic sampling of pancreatic specimens. Our data indicate that automated analysis of virtual pancreatic slides is highly reliable and yields results consistent with those obtained by conventional morphometric analysis. This new methodology will allow investigators to dramatically reduce the time required for β-cell mass measurement by automating high-resolution image capture and analysis of entire pancreatic sections.

scholarly journals Islet Inflammation Impairs the Pancreatic β-Cell in Type 2 Diabetes

Physiology ◽  
2009 ◽  
Vol 24 (6) ◽  
pp. 325-331 ◽  
Author(s):  
Marc Y. Donath ◽  
Marianne Böni-Schnetzler ◽  
Helga Ellingsgaard ◽  
Jan A. Ehses
Keyword(s):  
Type 2 Diabetes ◽  
Cell Mass ◽  
Metabolic Stress ◽  
Innate Immune ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Amyloid Deposits ◽  
Impaired Insulin ◽  
Islet Inflammation

Onset of Type 2 diabetes occurs when the pancreatic β-cell fails to adapt to the increased insulin demand caused by insulin resistance. Morphological and therapeutic intervention studies have uncovered an inflammatory process in islets of patients with Type 2 diabetes characterized by the presence of cytokines, immune cells, β-cell apoptosis, amyloid deposits, and fibrosis. This insulitis is due to a pathological activation of the innate immune system by metabolic stress and governed by IL-1 signaling. We propose that this insulitis contributes to the decrease in β-cell mass and the impaired insulin secretion observed in patients with Type 2 diabetes.

HDAC1 overexpression enhances β-cell proliferation by down-regulating Cdkn1b/p27

2018 ◽  
Vol 475 (24) ◽  
pp. 3997-4010 ◽  
Author(s):  
Carrie Draney ◽  
Matthew C. Austin ◽  
Aaron H. Leifer ◽  
Courtney J. Smith ◽  
Kyle B. Kener ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Survival ◽  
Cell Mass ◽  
Cyclin B1 ◽  
Β Cell ◽  
Histone Deacetylase 1 ◽  
Cell Cycle Inhibitor ◽  
Homeobox Transcription Factor ◽  
Glucose Stimulated Insulin Secretion

The homeobox transcription factor Nkx6.1 is sufficient to increase functional β-cell mass, where functional β-cell mass refers to the combination of β-cell proliferation, glucose-stimulated insulin secretion (GSIS) and β-cell survival. Here, we demonstrate that the histone deacetylase 1 (HDAC1), which is an early target of Nkx6.1, is sufficient to increase functional β-cell mass. We show that HDAC activity is necessary for Nkx6.1-mediated proliferation, and that HDAC1 is sufficient to increase β-cell proliferation in primary rat islets and the INS-1 832/13 β-cell line. The increase in HDAC1-mediated proliferation occurs while maintaining GSIS and increasing β-cell survival in response to apoptotic stimuli. We demonstrate that HDAC1 overexpression results in decreased expression of the cell cycle inhibitor Cdkn1b/p27 which is essential for inhibiting the G1 to S phase transition of the cell cycle. This corresponds with increased expression of key cell cycle activators, such as Cyclin A2, Cyclin B1 and E2F1, which are activated by activation of the Cdk4/Cdk6/Cyclin D holoenzymes due to down-regulation of Cdkn1b/p27. Finally, we demonstrate that overexpression of Cdkn1b/p27 inhibits HDAC1-mediated β-cell proliferation. Our data suggest that HDAC1 is critical for the Nkx6.1-mediated pathway that enhances functional β-cell mass.

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