C3 and early-onset autosomal dominant Alzheimer disease: Consistent with the previously reported destructive effect of the astrocytic nuclear factor κB (NF-κB)-activated C3 secretion on dendritic morphology and neuronal function [23,24], the upregulation of C3 played a pivotal role in driving synapse loss in the aging model [25] and several Alzheimer’s disease models [19,26].