TNF-α and IFN-γ induce neurotoxicity in human iPSC-derived astrocytes that is enhanced by aging

Abstract Astrocytes play a critical role in neuroinflammation and the pathogenesis of neurodegenerative diseases. Although inflammatory activation of astrocytes has been widely studied, the specific inflammatory conditions that elicit neurotoxic responses in human astrocytes, as opposed to rodent astrocytes, are not fully established. Here, we show that astrocytes derived from human induced pluripotent stem cells (iPSCs) respond to inflammatory triggers in a manner distinct from rodent astrocytes. Exposure to the pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) drove human astrocytes toward a pronounced neurotoxic state. This condition also induced neuronal hyperexcitability in astrocyte-neuron co-cultures, recapitulating key aspects of neuroinflammation-associated dysfunction. Compound screening identified Janus kinase inhibitors capable of preventing the acquisition of astrocyte neurotoxicity induced by TNF-α and IFN-γ, demonstrating the potential of neurotoxic astrocytes as a platform for drug screening. Furthermore, we demonstrated that lipopolysaccharide stimulation triggered TNF-α expression in a tri-culture of neurons, astrocytes, and microglia, leading to neurotoxicity in the presence of IFN-γ. Notably, astrocytes with senescent features showed enhanced neurotoxic responses to TNF-α and IFN-γ. These results provide insights into the interplay among cellular senescence, inflammation, and neurodegenerative diseases, highlighting astrocytes as potential targets in these diseases.