TREM2 and Alzheimer disease: Since the activation of triggering receptor expressed on myeloid cells 2 (TREM2), a cell surface receptor expressed in microglia and the major regulator of the transition from homeostatic microglia to disease‐associated microglia (Keren‐Shaul et al. 2017; Krasemann et al. 2017), has been linked to AD development (Jonsson et al. 2013; Guerreiro et al. 2013), we investigated whether repeated LPS stimulation of organotypic hippocampal slice cultures could change their expression.