Studying the cellular and molecular evolution of familiar Alzheimer'sdisease using human Cerebral Organoids

Abstract

The leading cause of dementia in the elderly is Alzheimer's disease (AD), and its increase is expected in the coming years. The histopathological hallmarks of AD are associated with the presence in brain of neurofibrillary tangles, due to the increase in hyperphosphorylated Tau protein, as well as amyloid plaques, due to the increase in amyloid peptide. There is no cure for AD and the treatments effective in slowing neurodegeneration. This lack of cure/treatments may be due to the lack of good study models. Until now, in vivo or in vitro monolayer cellular models have been used that do not allow recapitulating the complexity of the human brain, as well as the histopathology of AD in early stages of its development. For all these reasons, in this work we consider using the technology of three-dimensional cultures: human cerebral organoids (hCOs). In this work, using the protocol developed in our laboratory, we present the generation and characterisation of hCOs with mutations associated with familial AD (fAD) as compared with control hCOs. For this purpose, we used human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) as controls. As fAD models, we used hiPSCs with mutations in PSEN1 and APP duplication. Using immunohistochemistry and RT-qPCR we have analysed these hCOs for markers of neural precursors, brain cell types and synaptic markers, as well as the progression of AD phenotype (amyloid plaques). We have also performed electron microscopy studies to observe differences in the ultrastructure of the hCOs. We present the differences found that show the hCOs generated from hiPSCs with AD variants are experimental in vitro models that will allow further study of pathology.