Anna Gloyn, Postdoctoral Faculty Sponsor
The T-type calcium channel CaV3.2 regulates insulin secretion in the pancreatic beta-cell.
2022; 108: 102669
Voltage-gated Ca2+ (CaV) channel dysfunction leads to impaired glucose-stimulated insulin secretion in pancreatic beta-cells and contributes to the development of type-2 diabetes (T2D). The role of the low-voltage gated T-type CaV channels in beta-cells remains obscure. Here we have measured the global expression of T-type CaV3.2 channels in human islets and found that gene expression of CACNA1H, encoding CaV3.2, is negatively correlated with HbA1c in human donors, and positively correlated with islet insulin gene expression as well as secretion capacity in isolated human islets. Silencing or pharmacological blockade of CaV3.2 attenuates glucose-stimulated cytosolic Ca2+ signaling, membrane potential, and insulin release. Moreover, the endoplasmic reticulum (ER) Ca2+ store depletion is also impaired in CaV3.2-silenced beta-cells. The linkage between T-type (CaV3.2) and L-type CaV channels is further identified by the finding that the intracellular Ca2+ signaling conducted by CaV3.2 is highly dependent on the activation of L-type CaV channels. In addition, CACNA1H expression is significantly associated with the islet predominant L-type CACNA1C (CaV1.2) and CACNA1D (CaV1.3) genes in human pancreatic islets. In conclusion, our data suggest the essential functions of the T-type CaV3.2 subunit as a mediator of beta-cell Ca2+ signaling and membrane potential needed for insulin secretion, and in connection with L-type CaV channels.
View details for DOI 10.1016/j.ceca.2022.102669
View details for PubMedID 36347081