Dataset Information

Heterogeneous expression of CFTR in insulin-secreting ?-cells of the normal human islet.

ABSTRACT: Cystic fibrosis (CF) is due to mutations in the CF-transmembrane conductance regulator (CFTR) and CF-related diabetes (CFRD) is its most common co-morbidity, affecting ~50% of all CF patients, significantly influencing pulmonary function and longevity. Yet, the complex pathogenesis of CFRD remains unclear. Two non-mutually exclusive underlying mechanisms have been proposed in CFRD: i) damage of the endocrine cells secondary to the severe exocrine pancreatic pathology and ii) intrinsic ?-cell impairment of the secretory response in combination with other factors. The later has proven difficult to determine due to low expression of CFTR in ?-cells, which results in the general perception that this Cl-channel does not participate in the modulation of insulin secretion or the development of CFRD. The objective of the present work is to demonstrate CFTR expression at the molecular and functional levels in insulin-secreting ?-cells in normal human islets, where it seems to play a role. Towards this end, we have used immunofluorescence confocal and immunofluorescence microscopy, immunohistochemistry, RT-qPCR, Western blotting, pharmacology, electrophysiology and insulin secretory studies in normal human, rat and mouse islets. Our results demonstrate heterogeneous CFTR expression in human, mouse and rat ?-cells and provide evidence that pharmacological inhibition of CFTR influences basal and stimulated insulin secretion in normal mouse islets but not in islets lacking this channel, despite being detected by electrophysiological means in ~30% of ?-cells. Therefore, our results demonstrate a potential role for CFTR in the pancreatic ?-cell secretory response suggesting that intrinsic ?-cell dysfunction may also participate in the pathogenesis of CFRD.

SUBMITTER: Di Fulvio M

PROVIDER: S-EPMC7710116 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Heterogeneous expression of CFTR in insulin-secreting β-cells of the normal human islet.

Di Fulvio Mauricio M Bogdani Marika M Velasco Myrian M McMillen Timothy S TS Ridaura Cecilia C Kelly Lisa L Almutairi Mohammed M MM Kursan Shams S Sajib Abu A AA Hiriart Marcia M Aguilar-Bryan Lydia L

PloS one 20201202 12

Cystic fibrosis (CF) is due to mutations in the CF-transmembrane conductance regulator (CFTR) and CF-related diabetes (CFRD) is its most common co-morbidity, affecting ~50% of all CF patients, significantly influencing pulmonary function and longevity. Yet, the complex pathogenesis of CFRD remains unclear. Two non-mutually exclusive underlying mechanisms have been proposed in CFRD: i) damage of the endocrine cells secondary to the severe exocrine pancreatic pathology and ii) intrinsic β-cell imp ...[more]

PMID: 33264332

Similar Datasets

Project description:The physiological role of the beta-cell insulin receptor is unknown. To evaluate a candidate function, the insulin regulation of fluid-phase pinocytosis was investigated in a clonal insulinoma cell line (beta TC6-F7) and, for comparison, also in Chinese hamster ovary cells transfected with the human insulin receptor (CHO-T cells). In CHO-T cells, the net rate of fluid-phase pinocytosis was rapidly increased 3-4-fold over the basal rate by 100 nM insulin, with half-maximal stimulation at 2 nM insulin, as assayed by cellular uptake of horseradish peroxidase from the medium. Wortmannin, an inhibitor of phosphatidylinositol (PI)-3-kinase, blocked insulin-stimulated pinocytosis with an IC50 of 7.5 nM without affecting the basal rate of pinocytosis. In insulin-secreting beta TC6-F7 cells, the secretagogues glucose and carbachol (at maximally effective concentrations of 15 mM and 0.5 mM respectively) augmented fluid-phase pinocytosis 1.65-fold over the basal rate. Wortmannin also inhibited secretagogue-stimulated pinocytosis in these beta-cells with an IC50 of 7 nM but did not affect the basal rate of pinocytosis measured in the absence of secretagogues. Wortmannin did not influence either basal or secretagogue-induced insulin secretion. Although these beta TC6-F7 cells have cell-surface insulin receptors, adding exogenous insulin or insulin-like growth factor 1 did not affect their rate of fluid-phase pinocytosis, either in the absence or presence of secretagogues. From these observations, we conclude that: (1) in both insulin-secreting beta-cells and in conventional, insulin-responsive CHO-T cells, a common, wortmannin-sensitive reaction, which probably involves PI-3-kinase, regulates fluid-phase pinocytosis; (2) the insulin-receptor signal transduction pathway is dissociated from the regulation of fluid-phase pinocytosis in the insulin-secreting beta-cell line we studied; and (3) the enhancement of fluid-phase pinocytosis associated with secretagogue-induced insulin release in beta TC6-F7 cells is not attributable to autocrine activation of beta-cell surface insulin receptors.

Dataset Information

Heterogeneous expression of CFTR in insulin-secreting ?-cells of the normal human islet.

Publications

Heterogeneous expression of CFTR in insulin-secreting β-cells of the normal human islet.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets