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

NES2Y is a proliferating human insulin-secreting cell line that we have der ived from a patient with persistent hyperinsulinemic hypoglycemia of infanc y. This disease is characterized by unregulated insulin release despite pro found hypoglycemia, NES2Y cells, like beta-cells isolated from the patient of origin, lack functional ATP-sensitive potassium channels (K-ATP) and als o carry a defect in the insulin gene-regulatory transcription factor PDX1. Here, we report that the NES2Y beta-cells that are transfected with the gen es encoding the components of K-ATP channels in beta-cells, sulfonylurea re ceptor (SUR) 1 and Kir6.2, have operational K-ATP channels and show normal intracellular Ca2+ and secretory responses to glucose. However, these cells , designated NESK beta-cells, have impaired insulin gene transcription resp onses to glucose. NES2Y beta-cells that are transfected with either Kir6.2 or SUR1 alone do not express functional K-ATP channels and have impaired in tracellular free Ca2+ concentration-signaling responses to depolarization-d ependent beta-cell agonists. These findings document that in NES2Y beta-cel ls, coexpression of both subunits is critically required for fully operatio nal K-ATP channels and K-ATP channel-dependent signaling events. This artic le further characterizes the properties of the novel human beta-cell line, NES2Y and documents the usefulness of these cells in diabetes-related resea rch.