miRNA Regulation of Human Embryonic Stem Cell Differentiation

Abstract

Elucidating the role that microRNAs (miRNAs) and signaling transduction play in the directed differentiation of human embryonic stem cells (hESCs) into glucose-responsive, insulin-producing endocrine cells is critical to our understanding of systems biology and the development of cell-based therapeutics. To accomplish this, a biochemical understanding the underpinnings of hESC differentiation bias – the propensity of hESCs to differentiate into cells of a specific lineage – must be described in molecular detail. An inherent aspect of hESC culture is stress, and we hypothesize that stress is largely responsible for differentiation bias. Our results indicate that manipulating stress increases apoptosis and disrupts differentiation. Cells subjected to stress fail to become endocrine precursor cells and retain many characteristics of pluripotent cells. Many stresses induce massive apoptosis and result in a loss of up to 80 % of the cells. A consequence of the reduction in cell density is elevated stress signaling, dramatic changes in cell proliferation, maintenance of pluripotency markers, and a complete absence of transcription factors associated with pancreatic endocrine cell production. Coincident with changes in stress, we observed dramatic changes in correlated miRNAexpression, suggesting that cell stress may modulate miRNA transcription and ultimately hESC differentiation.