Early Insulin Signaling Defects and Oxidative Stress Kinase Activation Precede Tau Pathology in PS19 Tau Transgenic Mice

Pathological tau accumulation is a hallmark of Alzheimers disease (AD), yet its relationship with impaired insulin signaling remains unclear. Previously, we reported altered IRS1 phosphorylation reduced p IR beta, and GLUT3 expression in young AD transgenic mice prior to overt pathology. Here, we investigated insulin signaling and oxidative stress pathways in the Tau P301S (PS19) mouse model. We found that alterations in phospho IRS1, phospho IR beta, and the glucose transporters GLUT3 and GLUT4 occur before pathogenic tau deposition. In stable tau expressing human neuronal cell lines, tau expression was similarly associated with impaired insulin signaling. Concurrent dysregulation of insulin signaling and activation of oxidative stress responsive kinases, accompanied by increased microglial abundance, were evident in 2 month old PS19 mice and persisted into adulthood. Together, these findings demonstrate that insulin signaling abnormalities and oxidative stress kinase activation are early and sustained features of PS19 tauopathy, preceding the onset of overt neuropathology.