The serum and glucocorticoid-regulated kinase 1 in hypoxic renal injury

The serum-and glucocorticoid-inducible kinase 1 (SGK1) is a serine threonine protein kinase activated through the phosphatidylinositol 3-kinase (PI3-kinase) pathway and counteracting apoptosis. Protein expression and activation of SGK1 are increased in various models of cell stress. The present study explored the role of SGK1 in renal hypoxia/ischemia induced apoptosis. HEK 293 cells were exposed in vitro to hypoxia/reoxygenation (H/R), which increased SGK1 transcript levels, SGK1 protein abundance and SGK1 phosphorylation. H/R injury further enhanced the percentage of apoptotic cells, an effect significantly blunted by prior SGK1 overexpression. In vivo renal ischemia/reperfusion (I/R) injury increased SGK1 transcript levels and SGK1 protein abundance. I/R enhanced apoptosis, an effect significantly more pronounced in gene targeted mice lacking SGK1. In conclusion, SGK1 is up-regulated and counteracts apoptosis following H/R in vitro and ischemia in vivo.