In the present study, we investigated the role of reactive oxygen species（ROS） elevation induced by an anti-diabetic vanadium compound, vanadyl acetylacetonate（VO（acac）2）, in the regulation of lipolysis and glucose metabolism using differentiated 3T3L1 adipocytes as a model system. By confocal laser scanning microscopy, we found that VO（acac）2 induced ROS generation under high glucose stimulation, and the pretreatment of NADPH oxidase inhibitors could significantly reduce the elevated ROS level. Meanwhile, the decreased phosphorylated levels of AKT and the two key modulators of lipolysis（HSL and perilipin） were observed by western blot analysis. We also found that the contents of glycerol release were further reduced as well. In addition, the levels of key regulatory proteins, AS160 and GSK3β, in glucose metabolism pathway were correspondingly reduced. These findings demonstrated that ROS induced by vanadium compounds could act as a metabolic signal to activate AKT pathway to inhibit lipolysis and promote glucose transport and glycogen synthesis rather than by direct action by themselves. Our study contributed to elucidate the anti-diabetic effects of vanadium compounds and provided a theoretical basis for the further development of new vanadium complexes in the prevention and therapeutics of diabetes.
In the present study, we investigated the activation of protein kinase C （PKC） family in mouse embryonic fibroblast NIH3T3 cells using gadolinium chloride as a representative lanthanide ion. With live cell imaging system and confocal laser scanning microscopy, we found that the treatment of 50 μM GdCI3 promoted cell survival under the condition of serum-starvation. Moreover, better cell attachment and cytoskeleton reorganization were also observed. Additionally, GdC13 treatment resulted in the phosphorylation of PKC family at different time points. Furthermore, bisindolylmaleimide （a PKCpan inhibitor） could efficiently reduce the level of phosphorylated PKCpan （βIISer660）, alleviating ERK activation induced by GdC13. This finding indicated that the PKC activation was involved in GdC13-induced MAPK/ERK signaling and thus might contribute to GdClβ-indueed cell cycle progression and cell survival.
