Objectives: This study aimed to identify proteins important for the primitive gut tube differentiation from human embryonic stem cells (hESCs) by derivation method for pancreatic cells.
Methods: Proteins with altered expression levels in the process of differentiating to primitive gut tube from definitive endoderm of hESCs were investigated by comparative proteomic analysis using 2-dimensional gel electrophoresis and mass spectrometric analyses.
Results: Differentiation to primitive gut tube from hESCs was analyzed using differentiation marker genes and proteins. Twenty-seven protein spots with significant changes in intensity were found by 2-dimensional gel electrophoresis, and 24 proteins were further identified. These proteins were functionally annotated based on gene ontology. The expression levels of 3 proteins, RREB1, PDE6B, and CD209, involved in signal transduction, were validated using quantitative reverse transcription-polymerase chain reaction and Western blot. Their mRNA and protein expression levels increased in primitive gut tube but not in definitive endoderm or embryonic body.
Conclusions: The increase in expression of RREB1, PDE6B, and CD209 suggests that these proteins might play important roles in the differentiation of primitive gut tube cells from hESCs and in human primitive gut tube development into pancreas. Therefore, they could be developed as differentiation markers for identifying primitive gut tube cells.