Interleukin-1 induces tau phosphorylation and morphological changes in cultured human astrocytes

Tau phosphorylation is associated with neurite outgrowth and morphogenesis in neurons. Since inflammatory stimuli induce marked morphological changes in astrocytes, we examined the effect of interleukin 1alpha (IL-1alpha), an inflammatory cytokine, on the expression and phosphorylation of tau protein in cultured human astrocytes. Western blot analysis showed a rapid and transient increase (3-30 min) of tau phosphorylation at the AT8 epitope. The cells began to extend processes from 24 h after IL-1alpha stimulation. It is known that tau phosphorylation at the AT8 epitope reduces its ability to bind to, and stabilize, microtubules. The early tau phosphorylation induced by IL-1alpha might create a plastic environment for morphological changes in astrocytes.