Microglia play important roles in maintaining brain homeostasis and neurodegeneration. The discovery of genetic variants in genes predominately or exclusively expressed in myeloid cells, factors for Alzheimer’s disease (AD) highlights the importance of microglial biology in the brain. such as Apolipoprotein E (APOE) and triggering receptor expressed on myeloid cells 2 (TREM2), as the strongest risk factors for Alzheimer’s disease (AD) highlights the importance of microglial biology in the brain. The sequence, structure and function of several microglial proteins are poorly conserved across species, which has hampered the development of strategies aiming to modulate the expression of specific microglial genes. One way to target APOE and TREM2 is to modulate their expression using antisense oligonucleotides (ASOs). In this study, we identified selective and potent ASOs for human APOE and TREM2. We proved their efficacy in human iPSC microglia in vitro, as well as their pharmacological activity in vivo in a xenografted microglia model. We demonstrate ASOs targeting human microglia can modify their transcriptional profile and their response to amyloid-b plaques in vivo in a model of AD. This study is the first proof-of-concept that human microglial can be modulated using ASOs in a dose-dependent manner to manipulate microglia phenotypes in vivo. Since ASOs can have off-target effects, besides the expected decrease of APOE and TREM2 mRNA, this microarray was performed to determine the off-target profiles of the ASOs. iPSC derived microglia were treated with the ASOs with 1.25uM and 20uM dosages, and the compounds were incubated either 24hours or 48hours.
Overall design
Cell lysates were collected upon 24 and 48hours of treatment with the ASOs. RNA was extracted and hybridization was done on Affymetrix microarrays.
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