Jaffredo, M. | bioRxiv Science

bioRxiv2026

Pancreatic α-cells are required for nutrient homeostasis by regulating dynamic β-cell networks in islets

Pancreatic islets contain -, {beta}-, {gamma}- and {delta}-cells as sensors and actuators regulating glucose homeostasis. Despite the known importance of -cells, they are seemingly required for glucose tolerance only under metabolic stress. In an inducible model of -cell ablation in mice (GluDTR), glucose tolerance was considerably decreased by physiological addition of amino-acids mimicking meals. Analysis of islet {beta}-cell secretion and electrical activities using microelectrode arrays (MEA) detected only minor differences in GluDTR mice for glucose but revealed a major reduction upon addition of amino acids. Analysis of functional islet {beta}-cell networks by high density MEA revealed leading regions in different locations, a high degree of synchrony and the activation of large cell clusters. The characteristics of leading regions were preserved in GluDTR islets, but synchrony, cluster size and signal propagation speed were largely reduced. Thus, even without metabolic stress, -cells are required for nutrient homeostasis by regulating the dynamics of {beta}-cell networks. TeaserIslet -cells are required for meal tolerance by adjusting synchrony, cluster size and signal propagation of {beta}-cell networks.

physiology↗

bioRxiv2023

Electrophysiological characterisation of iPSC-derived human β-like cells and an SLC30A8 disease model.

iPSC-derived human {beta}-like cells (BLC) hold promise for both therapy and disease modelling, but their generation remains challenging and their functional analyses beyond transcriptomic and morphological assessments remain limited. Here, we validate an approach using multicellular and single cell electrophysiological tools to evaluate BLCs functions. The Multi-Electrode Arrays (MEAs) measuring the extracellular electrical activity revealed that BLCs are electrically coupled, produce slow potential (SP) signals like primary {beta}-cells that are closely linked to insulin secretion. We also used high-resolution single-cell patch-clamp measurements to capture the exocytotic properties, and characterize voltage-gated sodium and calcium currents. These were comparable to those in primary {beta} and EndoC-{beta}H1 cells. The KATP channel conductance is greater than in human primary {beta} cells which may account for the limited glucose responsiveness observed with MEA. We used MEAs to study the impact of the type 2 diabetes protective SLC30A8 allele (p.Lys34Serfs*50) and found that BLCs with this allele have stronger electrical coupling. Our data suggest that with an adapted approach BLCs from pioneer protocol can be used to evaluate the functional impact of genetic variants on {beta}-cell function and coupling. Article highlightsO_ST_ABSWhy did we undertake this study?C_ST_ABSiPSC-derived beta like cells (BLCs) from pioneering protocols are known for variable {beta}-cell functionality and mixed cell populations which greatly limits downstream functional assessment. To overcome this challenge, we used electrophysiological tools to provide a detailed functional assessment of BLCs. We then wanted to apply this approach to identify additional functional differences from BLCs carrying a protective Type 2 Diabetes SLC30A8 allele. What is the specific question(s) we wanted to answer?Can an electrophysiological approach provide detailed functional characterisation of iPSC-derived BLCs? Is this approach sensitive enough to capture functional differences resulting from SLC30A8 loss of function (lof)? What did we find?We found that BLCs generated from pioneer protocol shared electrophysiological features with human pancreatic {beta}-cells, and that a T2D-protective SLC30A8 lof allele improves the electrical coupling activity of human {beta}-cells. What are the implications of our findings?Our findings validate the use of intra- and extra-cellular electrophysiology to assess and monitor the functions of BLCs. Our approach opens the perspective of using MEAs to live-monitor the differentiation quality of iPSC-derived BLCs and to determine the functional consequences of diabetes-associated variants.

cell biology↗