Differential Effects of Itaconate and its Esters on the Glutathione and Glucose Metabolism of Cultured Primary Rat Astrocytes.

Itaconate is produced as endogenous metabolite by decarboxylation of the citric acid cycle intermediate cis-aconitate. As itaconate has anti-microbial and anti-inflammatory properties, this substance is considered as potential therapeutic drug for the treatment of inflammation in various diseases including traumatic brain injury and stroke. To test for potential adverse effects of itaconate on the viability and metabolism of brain cells, we investigated whether itaconate or its membrane permeable derivatives dimethyl itaconate (DI) and 4-octyl itaconate (OI) may affect the basal glucose and glutathione (GSH) metabolism of cultured primary astrocytes.

ATP Restoration by ATP-Deprived Cultured Primary Astrocytes.

A high cellular concentration of adenosine triphosphate (ATP) is essential to fuel many important functions of brain astrocytes. Although cellular ATP depletion has frequently been reported for astrocytes, little is known on the metabolic pathways that contribute to ATP restoration by ATP-depleted astrocytes. Incubation of cultured primary rat astrocytes in glucose-free buffer for 60 min with the mitochondrial uncoupler BAM15 lowered the cellular ATP content by around 70%, the total amount of adenosine phosphates by around 50% and the adenylate energy charge (AEC) from 0.

Consequences of a 2-Deoxyglucose Exposure on the ATP Content and the Cytosolic Glucose Metabolism of Cultured Primary Rat Astrocytes.

The glucose analogue 2-deoxyglucose (2DG) has frequently been used as a tool to study cellular glucose uptake and to inhibit glycolysis. Exposure of primary cultured astrocytes to 2DG caused a time- and concentration-dependent cellular accumulation of 2-deoxyglucose-6-phosphate (2DG6P) that was accompanied by a rapid initial decline in cellular ATP content. Inhibitors of mitochondrial respiration as well as inhibitors of mitochondrial uptake of pyruvate and activated fatty acids accelerated the ATP loss, demonstrating that mitochondrial ATP regeneration contributes to the partial maintenance of the ATP content in 2DG-treated astrocytes.

G6PDi-1 is a Potent Inhibitor of G6PDH and of Pentose Phosphate pathway-dependent Metabolic Processes in Cultured Primary Astrocytes.

Glucose-6-phosphate dehydrogenase (G6PDH) catalyses the rate limiting first step of the oxidative part of the pentose phosphate pathway (PPP), which has a crucial function in providing NADPH for antioxidative defence and reductive biosyntheses. To explore the potential of the new G6PDH inhibitor G6PDi-1 to affect astrocytic metabolism, we investigated the consequences of an application of G6PDi-1 to cultured primary rat astrocytes. G6PDi-1 efficiently inhibited G6PDH activity in lysates of astrocyte cultures.

β-lapachone-mediated WST1 Reduction as Indicator for the Cytosolic Redox Metabolism of Cultured Primary Astrocytes.

Electron cycler-mediated extracellular reduction of the water-soluble tetrazolium salt 1 (WST1) is frequently used as tool for the determination of cell viability. We have adapted this method to monitor by determining the extracellular WST1 formazan accumulation the cellular redox metabolism of cultured primary astrocytes via the NAD(P)H-dependent reduction of the electron cycler β-lapachone by cytosolic NAD(P)H:quinone oxidoreductase 1 (NQO1). Cultured astrocytes that had been exposed to β-lapachone in concentrations of up to 3 µM remained viable and showed an almost linear extracellular accumulation of WST1 formazan for the first 60 min, while higher concentrations of β-lapachone caused oxidative stress and impaired cell metabolism.

Sila-Ibuprofen.

The synthesis, characterization, biological activity, and toxicology of sila-ibuprofen, a silicon derivative of the most common nonsteroidal anti-inflammatory drug, is reported. The key improvements compared with ibuprofen are a four times higher solubility in physiological media and a lower melting enthalpy, which are attributed to the carbon-silicon switch. The improved solubility is of interest for postsurgical intravenous administration.