Morphology-based mammalian stem cell tests reveal potential developmental toxicity of donepezil.

Various compounds, including therapeutic drugs, can adversely impact the survival and development of embryos in the uterus. Identification of such development-interfering agents is a challenging task, although multi-angle approaches--including the use of in vitro toxicology studies involving embryonic stem cells--should alleviate some of the current difficulties. In the present study, we utilized the in vitro elongation of embryoid bodies (EBs) derived from mouse embryonal carcinoma stem cell line P19C5 as a model of early embryological events, specifically that of gastrulation and axial patterning. From our study, we identified donepezil, a medication indicated for the management of Alzheimer's disease, as a potential developmental toxicant. The extent of P19C5 EB axial elongation was diminished by donepezil in a dose-dependent manner. Although donepezil is a known inhibitor of acetylcholinesterase, interference of elongation was not mediated through this enzyme. Quantitative reverse-transcriptase PCR revealed that donepezil altered the expression pattern of a specific set of developmental regulator genes involved in patterning along the anterior-posterior body axis. When tested in mouse whole embryo culture, donepezil caused morphological abnormalities including impaired somitogenesis. Donepezil also diminished elongation morphogenesis of EBs generated from human embryonic stem cells. These results suggest that donepezil interferes with axial elongation morphogenesis of early embryos by altering the expression pattern of regulators of axial development.