Sulfonylurea receptor 1 and Kir6.2 expression in the novel human insulin-secreting cell line NES2Y.

Abstract

NES2Y is a proliferating human insulin-secreting cell line that we have derived from a patient with persistent hyperinsulinemic hypoglycemia of infancy. This disease is characterized by unregulated insulin release despite profound hypoglycemia. NES2Y cells, like beta-cells isolated from the patient of origin, lack functional ATP-sensitive potassium channels (KATP) and also carry a defect in the insulin gene-regulatory transcription factor PDX1. Here, we report that the NES2Y beta-cells that are transfected with the genes encoding the components of KATP channels in beta-cells, sulfonylurea receptor (SUR) 1 and Kir6.2, have operational KATP channels and show normal intracellular Ca2+ and secretory responses to glucose. However, these cells, designated NESK beta-cells, have impaired insulin gene transcription responses to glucose. NES2Y beta-cells that are transfected with either Kir6.2 or SUR1 alone do not express functional KATP channels and have impaired intracellular free Ca2+ concentration-signaling responses to depolarization-dependent beta-cell agonists. These findings document that in NES2Y beta-cells, coexpression of both subunits is critically required for fully operational KATP channels and KATP channel-dependent signaling events. This article further characterizes the properties of the novel human beta-cell line, NES2Y, and documents the usefulness of these cells in diabetes-related research.