CTSB and Alzheimer disease: Hence, to determine potential specific differentially expressed genes (DEGs) that are responsible for microglial inflammation between AD and depression, we first analyzed the overlap of common DEGs between disease-associated microglia (DAM) genes (Keren-Shaul et al., 2017) and depression-associated (DA) genes (Gao et al., 2018) using the Venn function, and found the common gene, CST7, which is an endogenous inhibitor of cysteine proteases.