Fyn-T Kinase Regulates DHA-Induced Pyroptosis in Immortalized Normal Human Astrocytes

Dysregulation of astroglia-mediated neuroinflammation is known to be involved in neurodegenerative diseases. Amongst multiple inflammatory pathways, pyroptosis is characterized by inflammatory cell death following inflammasome activation. Recently, the omega-3 poly-unsaturated fatty acid, DHA, has been identified as a pyroptosis inducer, although the underlying mechanisms remain unclear. In this study, we investigated the role of the alternatively spliced T-isoform of Fyn kinase (FynT) in DHA-induced astroglial pyroptosis. Immortalized normal human astrocytes (iNHA) expressing wild-type FynT (FynT-WT), kinase-dead mutant FynT (FynT-KD), or empty vector (EV) controls were treated with DHA and assessed for pyroptotic activation. We found that DHA-treated FynT-WT cells exhibited significantly reduced cytosolic lactate dehydrogenase release, pyroptotic morphology and markers (cleaved caspase-1 and its substrates, cleaved caspase-3 and gasdermin-D N fragments) compared to either EV or FynT-KD cells. No significant differences in pyroptotic activation were observed between EV and FynT-KD cells. In addition, no differences in immunoreactivities of pro- or anti-apoptotic markers (Bax or Bcl-2) were observed across the DHA-treated cells. In summary, our study postulates a negative regulatory role of FynT kinase in DHA-induced pyroptosis in astrocytes, with implications for further understanding neuroinflammatory mechanisms in neurodegenerative diseases and identification of potential therapeutic targets.