The p38 pathway is activated in Pick disease and progressive supranuclear palsy: a mechanistic link between mitogenic pathways, oxidative stress, and tau

In Pick disease and progressive supranuclear palsy (PSP), accumulations of phosphorylated τ are associated with oxidative stress, although the mechanism linking these features remains unknown. However, we suspected that the oxidative stress-induced activation of mitogen-activated protein kinases might lead to τ phosphorylation and accumulation as characteristic inclusion bodies. To test this notion, we investigated whether the activation of mitogen-activated protein kinases is involved in the pathogenesis of Pick disease and PSP. Our results show that the lesions of both Pick disease and PSP are associated with the activation of the p38 pathway (phospho-MKK6 and phospho-p38), one of the best characterized of the mitogen-activated protein kinase pathways. Based on these findings, we propose that the phosphorylation of τ is a direct consequence of the oxidative stress-induced activation of mitogen-activated protein kinases, including p38.