Diabetic kidney disease (DKD) is the most common cause of severe renal disease worldwide and the single strongest predictor of mortality in diabetes patients. Kidney steatosis has emerged as a critical trigger in the pathogenesis of DKD; however, the molecular mechanism of renal lipotoxicity remains largely unknown. Our recent studies in genetic mouse models, human cell lines, and well-characterized patient cohorts have identified serine/threonine protein kinase (STK)25 as a critical regulator of ectopic lipid storage in several metabolic organs prone to diabetic damage. Here, we demonstrate that overexpression of STK25 aggravates renal lipid accumulation and exacerbates structural and functional kidney injury in a mouse model of DKD. Reciprocally, inhibiting STK25 signaling in mice ameliorates diet-induced renal steatosis and alleviates the development of DKD-associated pathologies. Further, we find that STK25 silencing in human kidney cells protects against lipid deposition as well as oxidative and endoplasmic reticulum stress. Together, our results suggest that STK25 regulates a critical node governing susceptibility to renal lipotoxicity and that STK25 antagonism could mitigate DKD progression.
Emmelie Cansby, Mara Caputo, Lei Gao, Nagaraj M. Kulkarni, Annika Nerstedt, Marcus Ståhlman, Jan Boren, Rando Porosk, Ursel Soomets, Matteo Pedrelli, Paolo Parini, Hanns-Ulrich Marschall, Jenny Nyström, Brian W. Howell, Margit Mahlapuu