Short and long TNF-alpha exposure recapitulates canonical astrogliosis events in human induced pluripotent stem cells-derived astrocytes

Astrogliosis comprises a variety of changes in astrocytes that occur in a context-specific manner, triggered by temporally diverse signaling events that vary with the nature and severity of brain insults. However, most mechanisms underlying astrogliosis were described using animal models, which fail to reproduce some aspects of human astroglial signaling. Here, we report an in vitro model to study astrogliosis using human induced pluripotent stem cells (iPSC)-derived astrocytes which replicates aspects temporally intertwined of reactive astrocytes in vivo. We analyzed the time course of astrogliosis by measuring nuclear translocation of NF-kB, secretion of cytokines and changes in morphological phenotypes of human iPSC-derived astrocytes exposed to TNF-α. It was observed the NF-kB nuclear translocation, increases either in the inflammation-related cytokines secretion and gene expression for IL-1β, IL-6 and TNF-α following 24 h TNF-α stimulation. After 5 days, human iPSC-derived astrocytes exposed to TNF-α exhibited increases in vimentin and GFAP immunolabeling, elongated shape and shrinkage of nuclei, which is typical phenotypes of astrogliosis. Moreover, about a 50% decrease in D-[3H] aspartate uptake was observed over the astrogliosis course with no evident cell damage, which suggests astrocytic dysfunction. Taken together, our results indicate that cultured human iPSC-derived astrocytes reproduce canonical events associated to astrogliosis in a time dependent fashion. Our findings may contribute to a better understanding of mechanisms governing human astrogliosis. Furthermore, the approach described here presents a potential applicability as a platform to uncover novel biomarkers and new drug targets to refrain astrogliosis associated to human brain disorders.