TREM2 and cognition: Even though its protective and harmful roles during the pathogenesis of AD remain incompletely defined (Jay et al., 2015; Wang et al., 2015; Zhong et al., 2019), increasing evidence suggest that TREM2 is closely related to microgliosis, astrogliosis, neuroinflammation, neuronal loss and cognition impairment in AD (Jay et al., 2017).