Modulators of K⁺ Channels in Diabetology

There is one specific type of K⁺ channels profoundly involved in regulation of release of hormone insulin and inextricably connected to pathogenesis of diabetes mellitus. It is ATP-sensitive K⁺ channel (K_ATP). Recently, along with advances in genetic testing, a growing number of permanent neonatal diabetes (PND) has been diagnosed, which is a monogenic form of diabetes of even earlier onset than maturity onset diabetes of the young (MODY). Neonatal diabetes can result from mutations in Kir6.2 or sulfonylurea receptor (SUR1) subunits of the ATP-sensitive K⁺ channel. The pathogenesis is based on the mechanism of permanent activation and wide opening of the K_ATP potassium channel of the β-cells. An important and interesting feature of the disease clinical picture is sustained therapeutic response to sulfonylureas in the treatment of neonatal diabetes caused by mutation in the KCNJ11 and ABCC8 genes. Mechanism of action of this class of medicines involves interaction with the SUR1 subunit of the K_ATP channel in the β cell. However, there are some types of neonatal diabetes which fail to respond to the sulfonylurea therapy. An example of this is the most severe phenotype of neonatal diabetes accompanied with disorders of the nervous system, muscle weakness and psychomotor development delay, which is a so-called DEND syndrome. Analogs of GLP-1 and antagonist of GLP-1 receptor may provide a new way of treatment in K_ATP dependent disorders. These hormones may modulate the beta cells response by influencing K_ATP channels and cAMP independently.

Keywords: Diabetes mellitus, Permanent Neonatal Diabetes (PND), Maturity onset diabetes of the young (MODY), SUR 1, Kir6.2, Sulfonylureas, KCNJ11 gene, ABCC8 gene, DEND syndrome, GLP-1 analogs.