MAPT and Alzheimer disease: To generate p-tau, we adopted a sequential kinase phosphorylation strategy using PKA and SAPK3/MAPK12 developed by Meng et al.18 This novel method yields AD-specific epitopes (AT8, AT100, and PHF-1) without relying on artificial aggregation agents like heparin,37 which allows us to capture early astrocytic responses to pathogenic tau under sub-cytotoxic, disease-relevant conditions.38