APP and Alzheimer disease: For example, OL-1, an ASO targeting the APP mRNA region corresponding to the 17–30 amino acid fragment of Aβ, lowered APP expression in AD mouse models Tg2576 (APPswe) and SAMP8 mice.26,27 Another important study utilised a splice-switching ASO that causes skipping of the APP exon that encodes proteolytic cleavage sites required for Aβ peptide production.28 This study successfully demonstrated that ASO treatment in this context can lead to a reduction in Aβ42 levels in the hippocampus of wild-type C57BL/6J mice.