Blocking Ca2+ Channel ß3 Subunit Reverses Diabetes.

ABSTRACT

Voltage-gated Ca2+ channels (Cav) are essential for pancreatic beta cell function as they mediate Ca2+ influx, which leads to insulin exocytosis. The ß3 subunit of Cav (Cavß3) has been suggested to regulate cytosolic Ca2+ ([Ca2+]i) oscillation frequency and insulin secretion under physiological conditions, but its role in diabetes is unclear. Here, we report that islets from diabetic mice show Cavß3 overexpression, altered [Ca2+]i dynamics, and impaired insulin secretion upon glucose stimulation. Consequently, in high-fat diet (HFD)-induced diabetes, Cavß3-deficient (Cavß3-/-) mice showed improved islet function and enhanced glucose tolerance. Normalization of Cavß3 expression in ob/ob islets by an antisense oligonucleotide rescued the altered [Ca2+]i dynamics and impaired insulin secretion. Importantly, transplantation of Cavß3-/- islets into the anterior chamber of the eye improved glucose tolerance in HFD-fed mice. Cavß3 overexpression in human islets also impaired insulin secretion. We thus suggest that Cavß3 may serve as a druggable target for diabetes treatment.