CCL2 and Alzheimer disease: Notably, IL‐3 significantly increased Ccl2 levels in AAV‐hα‐Syn mice and hα‐Syn fibril‐treated primary microglia (Figure 4I,J), which was consistent with IL‐3′s effects in an AD mouse model.[8] Moreover, we found that IL‐3 increased the signal of CCR2 in microglia in the SNpc of AAV‐hα‐Syn mice (Figure 4K), suggesting that CCR2 is critical for IL‐3 activation of microglial IL‐3Rα.