The arrangement of β cells within islets of Langerhans is critical for insulin release through the generation of rhythmic activity. A privileged role for individual β cells in orchestrating these responses has long been suspected, but not directly demonstrated. We show here that the β cell population in situ is operationally heterogeneous. Mapping of islet functional architecture revealed the presence of hub cells with pacemaker properties, which remain stable over recording periods of 2 to 3 hr. Using a dual optogenetic/photopharmacological strategy, silencing of hubs abolished coordinated islet responses to glucose, whereas specific stimulation restored communication patterns. Hubs were metabolically adapted and targeted by both pro-inflammatory and glucolipotoxic insults to induce widespread β cell dysfunction. Thus, the islet is wired by hubs, whose failure may contribute to type 2 diabetes mellitus.
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http://dx.doi.org/10.1016/j.cmet.2016.06.020 | DOI Listing |
World J Diabetes
January 2025
Department of Gastroenterology, The First People's Hospital of Foshan, Foshan 528000, Guangdong Province, China.
In this article, we review the study by Jin , which examined the role of intestinal glucagon-like peptide-1 (GLP-1) in counterregulatory responses to hypoglycemia in patients with type 1 diabetes mellitus (T1DM). With the global rise of T1DM, there is an increased burden on society and healthcare systems. Due to insulin therapy and islet dysfunction, T1DM patients are highly vulnerable to severe hypoglycemia, a leading cause of mortality.
View Article and Find Full Text PDFBrain Behav Immun Health
February 2025
Laboratory of Immuno-Endocrinology, Diabetes and Metabolism, Instituto de Investigaciones en Medicina Traslacional (IIMT), CONICET-Universidad Austral, Pilar, Argentina.
Pancreatic β-cells are specialized in secreting insulin in response to circulating nutrients, mainly glucose. Diabetes is one of the most prevalent endocrine-metabolic diseases characterized by an imbalance in glucose homeostasis, which result mainly from lack of insulin production (type 1 diabetes) or insufficient insulin and peripheral insulin resistance (type 2 diabetes), both influenced by genetic and environmental components. Pancreatic β-cell dysfunction and islet inflammation are common characteristics of both types of the disease.
View Article and Find Full Text PDFActa Physiol (Oxf)
February 2025
Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.
Aim: Somatostatin from pancreatic δ-cells is a paracrine regulator of insulin and glucagon secretion, but the release kinetics and whether secretion is altered in diabetes is unclear. This study aimed to improve understanding of somatostatin secretion by developing a tool for real-time detection of somatostatin release from individual pancreatic islets.
Methods: Reporter cells responding to somatostatin with cytoplasmic Ca concentration ([Ca]) changes were generated by co-expressing somatostatin receptor SSTR2, the G-protein Gα15 and a fluorescent Ca sensor in HeLa cells.
Diabetol Metab Syndr
January 2025
Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Tehran University of Medical Sciences, Tehran, Iran.
Background And Aims: Type 2 diabetes mellitus (T2DM) is usually complicated by cardiovascular diseases, hyperglycemia, and obesity, which worsen the outcome for the patient. Since recent evidence underlines the epigenetic role of glucagon-like peptide-1 receptor agonists (GLP-1RAs) in the management of these comorbidities, this study compared the effects of these agents, namely liraglutide, semaglutide, dulaglutide, and exenatide, on miRNA regulation in the management of T2DM.
Results: GLP-1RAs modify the expression of miRNAs involved in endothelial function, sugar metabolism, and adipogenesis, including but not limited to miR-27b, miR-130a, and miR-210.
Cells
January 2025
Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 3K7, Canada.
Bi-hormonal islet endocrine cells have been proposed to represent an intermediate state of cellular transdifferentiation, enabling an increase in beta-cell mass in response to severe metabolic stress. Beta-cell plasticity and regenerative capacity are thought to decrease with age. We investigated the ontogeny of bi-hormonal islet endocrine cell populations throughout the human lifespan.
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