[HTML][HTML] Intercellular communication in the islet of langerhans in health and disease

XW Ng, YH Chung, DW Piston - Comprehensive Physiology, 2021 - ncbi.nlm.nih.gov
XW Ng, YH Chung, DW Piston
Comprehensive Physiology, 2021ncbi.nlm.nih.gov
Blood glucose homeostasis requires proper function of pancreatic islets, which secrete
insulin, glucagon and somatostatin from the β-, α-and δ-cells respectively. Each islet cell
type is equipped with intrinsic mechanisms for glucose sensing and secretory actions, but
these intrinsic mechanisms alone cannot explain the observed secretory profiles from intact
islets. Regulation of secretion involves interconnected mechanisms among and between
islet cell types. Islet cells lose their normal functional signatures and secretory behaviors …
Abstract
Blood glucose homeostasis requires proper function of pancreatic islets, which secrete insulin, glucagon and somatostatin from the β-, α-and δ-cells respectively. Each islet cell type is equipped with intrinsic mechanisms for glucose sensing and secretory actions, but these intrinsic mechanisms alone cannot explain the observed secretory profiles from intact islets. Regulation of secretion involves interconnected mechanisms among and between islet cell types. Islet cells lose their normal functional signatures and secretory behaviors upon dispersal as compared to intact islets and in vivo. In dispersed islet cells, the glucose response of insulin secretion is attenuated from that seen from whole islets, coordinated oscillations in membrane potential and intracellular Ca 2+ activity, as well as the two-phase insulin secretion profile are missing, and glucagon secretion displays higher basal secretion profile and a reverse glucose-dependent response from that of intact islets. These observations highlight the critical roles of intercellular communication within the pancreatic islet, and how these communication pathways are crucial for proper hormonal and non-hormonal secretion and glucose homeostasis. Further, misregulated secretions of islet secretory products that arise from defective intercellular islet communication are implicated in diabetes. Intercellular communication within the islet environment comprises multiple mechanisms, including electrical synapses from gap junctional coupling, paracrine interactions among neighboring cells, and direct cell-to-cell contacts in the form of juxtacrine signaling. In this review, we describe the various mechanisms that contribute to proper islet function for each islet cell type and how intercellular islet communications are coordinated among the same and different islet cell types.
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