C3AR1 and Alzheimer disease: AD-tau-injected Trem2−/− mice showed a lower expression of genes related to microglial function (Tbc1d4, Nrm, Ltc4s, CD86, C3ar1, Slamf9, Mmp12), the adaptative immune response (Egfr, Ptprc, Ago4, CD19, Was, Fcrlb), inflammatory signaling (lkbke), and cytokine signaling (Osgin1, Egfr, CD70) than AD-tau-injected WT mice (Figure 5A, pink dots).