Surprisingly, the presence of astrocytes induces upregulation of disease-associated microglia (DAM) genes, including TREM2, SPP1, APOE, and GPNMB in microglia. Additionally, while familial Alzheimer’s disease neurons induce a prototypical inflammatory response in microglia, the DAM signature is significantly dampened. This evidence concerns the gene GPNMB and familial Alzheimer disease.