Maternal diabetes is associated with various risks during pregnancy, including structural birth defects. Gene dysregulation and reduced progenitor cell formation and differentiation are two major mechanisms that are implicated in diabetic embryopathy. Our lab has previously shown that E14 mouse embryonic stem cells (mESCs) grown in high glucose conditions have delayed differentiation to both neurons and cardiomyocytes. However, treatment of 4-PBA (4-phenylbutyrate), a chemical chaperone used as an endoplasmic reticulum (ER) stress inhibitor, rescued this delay of differentiation to neurons. On the other hand, high glucose increased mESC pluripotency and activated the unfolded protein response (UPR) in undifferentiated conditions, specifically the protein kinase RNA-like endoplasmic reticulum kinase (PERK) pathway. To determine the role of the UPR in enhanced mESC pluripotency by high glucose, E14 mESCs grown in high glucose were treated with or without 4-PBA for 8 days. Untreated E14 mESCs grew in dome-shaped colonies with defined edges, while 4-PBA-treated cells grew in flat colonies with cells emerging out of the colonies, indicative of a more differentiated state. Microarray analysis showed that 4-PBA-treated cells had upregulated expression of primed state markers and downregulated expression of pluripotency markers, compared to untreated cells. Our results suggest that inhibition of the UPR through ER stress inhibition abolishes the stimulatory effect of high glucose on mESC pluripotency, leading to a shift from native state to a more differentiated ESC stage.
W. Sun: None. P. Yang: None. F. Ye: None. P. Yang: None.
National Institutes of Health