Generation of disease-relevant neurons from human pluripotent stem cells

Abstract

This thesis describes investigations into exogenous factors that influence fate-choices during human pluripotent stem cell (PSC) differentiation in vitro. I describe novel growth factor environments and small molecule regimes that provide patterning signals enabling directed differentiation of human PSCs towards biomedically relevant neurons. I provide evidence that the TGFβ growth factor Activin can promote ventral telencephalic differentiation. Small adjustments in Activin administration can produce an over-representation of forebrain derived medium spiny neurons and cortical interneurons, with significance in Huntington’s disease and epilepsy respectively. Additionally, I manipulate the earliest growth factor environments of PSC differentiation to lead to broad changes in rostro-caudal patterning. Inhibiting FGF signalling leads to a midbrain-like phenotype that can be further differentiated towards a ventral midbrain dopaminergic fate, a cell type that degenerates in Parkinson’s disease. Our novel manipulations and differentiation protocols provide insights into early events in human development, which would otherwise be impossible to study. This logic can also be applied to investigate diseased states during human development and ageing via use of disease-specific cell lines. The mature neurons produced may provide a tool that can be applied to large-scale drug screening assays and toxicology testing as well as having the potential for cell based therapies in future years.