APP and Alzheimer disease: Additionally, differential expression profiles of circRNAs in some AD cellular or animal models, including Amyloid precursor protein (APP)/PS1, Tg2576, 5xFAD, SAMP8, or Aβ administration, were constructed (Zhang et al., 2017, 2021; Wang et al., 2018; Lee et al., 2019; Ma et al., 2019; Nam et al., 2019) (Table 1).