Liraglutide, lixisenatide, semaglutide, exendin-4 or NLY01 [a pegylated and rather poorly BBB-penetrant version of Exendin-4 (Yun et al., 2018; Lv et al., 2021; Park et al., 2021)] reduced IBA-1 or Mac-1 immunoreactivity, indicative of microgliosis, in the hippocampus (Cai et al., 2018; Holubova et al., 2019; Salles et al., 2020; Paladugu et al., 2021; Park et al., 2021), cortex (McClean et al., 2011, 2015; Long-Smith et al., 2013; Paladugu et al., 2021) and global brain tissue (McClean and Holscher, 2014a) of aged WT, APP/PS1, 5xFAD, 3 × Tg-AD or sporadic STZ AD mice. The gene discussed is PSEN1; the disease is Alzheimer disease.