C3 and C3aR are specifically expressed in astrocytes and microglia, respectively. A, C3 RNA in situ hybridization combined with anti-GFAP antibody staining in 12-month-old wild-type mice. Sense, Sense probe for C3; antisense, antisense probe for C3. B, Representative anti-C3 and anti-GFAP double immunostaining in 3-month-old WT and C3 KO mice. C, C3aR RNA in situ hybridization combined with anti-Iba1 antibody staining in 12-month-old wild-type mice. Sense, Sense probe for C3aR; antisense, antisense probe for C3aR. D, Representative anti-C3aR and anti-Iba1 coimmunostaining in 3-month-old WT and C3aR KO mice. Arrowheads mark representative colocalized cells. Scale bars: 50 μm.