Endosomal structure and APP biology are not altered in preclinical cellular models of Down syndrome

Abstract

Individuals who have Down syndrome (trisomy 21) are at greatly increased risk of developing Alzheimers disease - dementia. Alzheimers disease is characterised by the accumulation in the brain of amyloid-{beta} plaques that are a product of amyloid precursor protein, encoded by the APP gene on chromosome 21. In Down syndrome the first site of amyloid-{beta} accumulation is within endosomes and changes to endosome biology occur early in disease. Here we determine if primary mouse embryonic fibroblasts isolated from two mouse models of Down syndrome can be used to study endosome and APP cell biology. We report that in these cellular models of Down syndrome endosome number, size and APP processing are not altered, likely because APP is not dosage sensitive in these models, despite three copies of App.