The Menadione-Mediated WST1 Reduction by Cultured Astrocytes Depends on NQO1 Activity and Cytosolic Glucose Metabolism.

The Menadione-Mediated WST1 Reduction by Cultured Astrocytes Depends on NQO1 Activity and Cytosolic Glucose Metabolism. Neurochem Res. 2020 Jan 04;: Authors: Ehrke E, Steinmeier J, Stapelfeldt K, Dringen R Abstract The reduction of water-soluble tetrazolium salts (WSTs) is frequently used to determine the metabolic integrity and the viability of cultured cells. Recently, we have reported that the electron cycler menadione can efficiently connect intracellular oxidation reactions in cultured astrocytes with the extracellular reduction of WST1 and that this menadione cycling reaction involves an enzyme. The enzymatic reaction involved in the menadione-dependent WST1 reduction was found strongly enriched in the cytosolic fraction of cultured astrocytes and is able to efficiently use both NADH and NADPH as electron donors. In addition, the reaction was highly sensitive towards dicoumarol with Kic values in the low nanomolar range, suggesting that the NAD(P)H:quinone oxidoreductase 1 (NQO1) catalyzes the menadione-dependent WST1 reduction in astrocytes. Also, in intact astrocytes, dicoumarol inhibited the menadione-dependent WST1 reduction in a concentration-dependent manner with half-maximal inhibition observed at around 50 nM. Moreover, the menadione-dependent WST1 reduction by viable astrocytes was strongly affected by the availability of glucose. In the absence of glucose only residual WST1 reduction was observed, while a concentratio...
Source: Neurochemical Research - Category: Neuroscience Authors: Tags: Neurochem Res Source Type: research