Digoxin Induces Human Astrocyte Reaction In Vitro.

Area of Science:

• Neuroscience
• Toxicology
• Cellular Metabolism

Background:

• Astrocyte reaction is a key indicator of central nervous system (CNS) injury and neurotoxicity, extensively studied in rodents but less so in humans.
• Astrocytes are crucial for cerebral energy metabolism and neuroinflammation, with age-related changes suggesting a link between metabolism and inflammation.
• The interplay between astrocyte energy metabolism and reactivity in the context of neurotoxicity remains largely unexplored.

Purpose of the Study:

• To investigate the hypothesis that astrocyte energy metabolism changes are coupled to their activation by xenobiotics.
• To explore the relationship between energy metabolism and astrocyte reactivity in human cells exposed to a xenobiotic and a pro-inflammatory cytokine.

Main Methods:

• Human ReN-derived astrocytes were exposed to digoxin (a xenobiotic) or TNFα (a cytokine).
• Assessed astrocyte reaction and energy metabolic changes using immunostaining, gene expression, proteomics, metabolomics, and extracellular flux analysis.
• Analyzed changes after 24 hours of exposure.

Main Results:

• Significant astrocyte reaction was observed in response to both digoxin and TNFα.
• Increased glycolysis was noted at low digoxin concentrations (0.1 and 0.5 µM) and following TNFα exposure.
• This suggests that heightened glycolysis is a common feature of reactive astrocytes, irrespective of the stimulus.

Conclusions:

• Astrocyte activation, whether by cytokines or xenobiotics, is intrinsically linked to energy metabolism in human astrocytes.
• Elevated glycolysis can serve as a valuable endpoint for identifying astrocyte activation by potential neurotoxic compounds in vitro.
• ReN-derived astrocytes offer a model system to elucidate neurotoxicity mechanisms and assess the direct impact of chemicals on astrocytes.