Abstract: Pattern formation is one of the most important processes during embryogenesis. It is commonly accepted that pattern formation is mainly driven by morphogen gradient. However, heterogeneous pattern still exists in 2D monolayer culture system that does not have obvious growth factor gradient. In this project, we use 2D monolayer human pluripotent stem cell (hESC) culture to study pattern formation in hPSC colonies. We observe that cell fate pattern is determined by the location of individual cells in a colony, and the spatial distribution can be associated with the pattern of metabolic activities in a colony. We show that endogenous protease influences metabolic pattern through the activation of protease-activated receptor (PAR). PAR pathway can further interact with Calcium and metabolism related signaling pathway that is important for fate pattern. Although under 2D monolayer culture condition, metabolic changes caused by PAR itself are not enough to affect or change cell fate, it can still activate a series of signaling and regulate gene expression. This study highlights novel autocrine feedback important for pattern formation and cell fate determination.
