Reduction of Shp‐2 Expression by Small Interfering RNA Reduces Murine Embryonic Stem Cell‐Derived In Vitro Hematopoietic Differentiation

Shp‐2 is a member of a small family of cytoplasmic Src homology 2 (SH2) domain‐containing protein tyrosine phosphatases. Although Shp‐2 has been shown to be necessary for hematopoiesis using a mouse model expressing a mutant residual protein (Shp‐2Δ/Δ), we used small interfering RNA (siRNA) to reduce Shp‐2 expression and examined the consequences on embryonic stem cell (ESC)‐derived hemangioblast, primitive, and definitive hematopoietic development. We found that at a concentration of 50 nM, Shp‐2 siRNA effectively diminished Shp‐2 expression in differentiating embryoid bodies. Hemangioblast, primitive, and definitive hematopoietic progenitor formation was decreased significantly after transfection with Shp‐2 siRNA but not with scrambled siRNA. Because Shp‐2 is involved in signals emanating from the basic fibroblast growth factor (bFGF) receptor, we asked whether Shp‐2 functions in bFGF‐mediated hemangioblast development. Reduction of Shp‐2 expression using siRNA, but not scrambled siRNA, blocked the bFGF‐induced increase in hemangioblast development. Using siRNA as an independent method of reducing Shp‐2 function, in contrast to the mutant mouse model (Shp‐2Δ/Δ) previously used, we demonstrate that Shp‐2 is required in hemangioblast, primitive, and definitive progenitor hematopoietic development and that Shp‐2 is integrally necessary for bFGF‐mediated hemangioblast production.