CK2 modulates adipocyte insulin-signaling and is up-regulated in human obesity
SCIENTIFIC REPORTS
Authors: Borgo, Christian; Milan, Gabriella; Favaretto, Francesca; Stasi, Fabio; Fabris, Roberto; Salizzato, Valentina; Cesaro, Luca; Belligoli, Anna; Sanna, Marta; Foletto, Mirto; Prevedello, Luca; Vindigni, Vincenzo; Bardini, Romeo; Donella-Deana, Arianna; Vettor, Roberto
Abstract
Insulin plays a major role in glucose metabolism and insulin-signaling defects are present in obesity and diabetes. CK2 is a pleiotropic protein kinase implicated in fundamental cellular pathways and abnormally elevated in tumors. Here we report that in human and murine adipocytes CK2-inhibition decreases the insulin-induced glucose-uptake by counteracting Akt-signaling and GLUT4-translocation to the plasma membrane. In mice CK2 acts on insulin-signaling in adipose tissue, liver and skeletal muscle and its acute inhibition impairs glucose tolerance. Notably, CK2 protein-level and activity are greatly up-regulated in white adipose tissue from ob/ob and db/db mice as well as from obese patients, regardless the severity of their insulin-resistance and the presence of pre-diabetes or overt type 2 diabetes. Weight loss obtained by both bariatric surgery or hypocaloric diet reverts CK2 hyper-activation to normal level. Our data suggest a central role of CK2 in insulin-sensitivity, glucose homeostasis and adipose tissue remodeling. CK2 up-regulation is identified as a hallmark of adipose tissue pathological expansion, suggesting a new potential therapeutic target for human obesity.
Factor XII - What's important but not commonly thought about
RESEARCH AND PRACTICE IN THROMBOSIS AND HAEMOSTASIS
Authors: Schmaier, Alvin H.; Stavrou, Evi X.
Abstract
Factor XII (FXII) becomes a serine protease when blood is exposed to artificial medical surfaces or when pathologic surfaces arise in disease states leading to its autoactivation. Initiation of the blood coagulation cascade was the first recognized activity of FXIIa. Blocking FXIIa activity formed on artificial medical surfaces should reduce induced blood coagulation leading to thrombosis. In contrast to FXII enzymatic activities, less is known about zymogen FXII functions. Studies show that zymogen FXII has biologic activity in various cells in vivo. In endothelium, FXII stimulates cell growth and proliferation and, in vivo, neoangiogenesis after injury. In fibroblasts, transforming growth factor-beta increases FXII expression, which in turn stimulates fibroblast proliferation, contributing to tissue fibrosis. In neutrophils, FXII stimulates Akt2 to initiate neutrophil adhesion, migration, and chemotaxis, priming events leading to NETosis. Factor FXII deficiency leads to decreased neutrophil recruitment and improved wound healing. In dendritic cells, FXII contributes to neuroinflammation, and its deficiency or pharmacologic inhibition renders mice less susceptible to autoimmune encephalomyelitis. These combined studies indicate that FXII also contributes to multiple components of the inflammatory response. In sum, targeting FXII's biologic activities may provide novel approaches to reduce thrombosis and the inflammatory response in various disease states.