Role of Wnt/Beta-catenin path way in differentiation of mouse es cells to cortical progenitors

The Wnt/β-catenin was reported to promote both pluripotency maintenance and differentiation. Treatment with Wnt and Nodal antagonists-Dkk1 and Lefty-1 or Wnt antagonist-IWP2 in serumfree floating culture of embryoid body-like aggregates (SFEBq) promoted ES differentiation to neural lineages with high efficiency. Surprisingly treatment with Wnt pathway agonist-Wnt3a down-regulated stem cells surface markers (GCTM2, CD9) in hES cells and evoked morphology characteristic of differentiation. We used Wnt inhibitors (iCRT3 and IWP2) and Nodal inhibitor (SB431542) alone or in combination to investigate the differentiation of mouse ES cells to cortical progenitors. SFEBq aggregates were differentiated and analyzed for the expression of the markers of cortical progenitors. The expression of Pax6, Sox1 and Foxg1 in SFEBq without inhibitors peaked on day 7 of differentiation while IWP2 and iCRT/SB431542 aggregates exhibited a delayed expression of cortical markers with highest expression on day 11 of differentiation. Moreover, the addition of Wnt3a on day 7 to 11 increased cell proliferation and sustained the expression of cortical progenitors markers. Taken together we observed an influence of Wnt regulation on neuronal differentiation and on proliferation of cells at later stage of differentiation.