PTGS1 and Alzheimer disease: Employing rat primary microglia morphology assay, we identified two COX-1/2 metabolites 12-HHTrE and PGE2 from the serum or brain of Abx-treated mice inoculated with AD-FMT (Supplementary Fig. 9), which exhibit robust microglia activation in the brain (Fig. 3C, D).