The cellular form of the prion protein guides the differentiation of human embryonic stem cells into neuron-, oligodendrocyte-, and astrocyte-committed lineages

Abstract

Prion protein, PrPC, is a glycoprotein that is expressed on the cell surface beginning with the early stages of embryonic stem cell differentiation. Previously, we showed that ectopic expression of PrPC in human embryonic stem cells (hESCs) triggered differentiation toward endodermal, mesodermal, and ectodermal lineages, whereas silencing of PrPC suppressed differentiation toward ectodermal but not endodermal or mesodermal lineages. Considering that PrPC might be involved in controlling the balance between cells of different lineages, the current study was designed to test whether PrPC controls differentiation of hESCs into cells of neuron-, oligodendrocyte-, and astrocyte-committed lineages. PrPC was silenced in hESCs cultured under three sets of conditions that were previously shown to induce hESCs differentiation into predominantly neuron-, oligodendrocyte-, and astrocyte-committed lineages. We found that silencing of PrPC suppressed differentiation toward all three lineages. Similar results were observed in all three protocols, arguing that the effect of PrPC was independent of differentiation conditions employed. Moreover, switching PrPC expression during a differentiation time course revealed that silencing PrPC expression during the very initial stage that corresponds to embryonic bodies has a more significant impact than silencing at later stages of differentiation. The current work illustrates that PrPC controls differentiation of hESCs toward neuron-, oligodendrocyte-, and astrocyte-committed lineages and is likely involved at the stage of uncommitted neural progenitor cells rather than lineage-committed neural progenitors.