APP and Alzheimer disease: Moreover, Morello et al. (2018) showed that calcitriol can cause neuronal proliferation in primary cultures of murine neural progenitor cells and improve neurogenesis in transgenic Alzheimer’s disease (AD)-like mice [5XFAD model, which expresses human amyloid precursor protein (APP) and presenilin 1 (PSEN1) transgenes with a total of five AD-linked mutations: the Swedish (K670N/M671L), Florida (I716V), and London (V717I) mutations in APP, and the M146L and L286V mutations in PSEN1).