Poster Presentation 6th Australian Health and Medical Research Congress 2012

Ectopic Expression of Wnt-1 in Mouse Embryonic Stem Cells Leads to Dose-dependent Divergent Phenotypes (#383)

Joseph Y Chen 1 , Tiziano Barberi 1
  1. Monash University, Clayton, VIC, Australia

Many in vivo and in vitro studies have been performed to determine the role of Wnt-signaling during development. Discordant in vitro studies, using mouse embryonic stem cells (mESCs), reported that inhibition or activation of the canonical Wnt-signaling pathway could promote or inhibit the differentiation of these cells into neural lineages. Therefore, in the present study we aimed at investigating the role of Wnt-signaling during neural differentiation of mESCs. We first established transgenic mESCs expressing Wnt-1 from two different mESC lines (B6 and R1) and selected clones displaying different levels of Wnt-1 expression. When induced to differentiate towards a neural fate, low Wnt-1-expressing clones generally exhibited an accelerated or unperturbed neural differentiation potential compared to a mock-transfected control. Notably, a preliminary analysis performed on one low Wnt-1-expressing clone from the B6 cell line showed an increase in the expression of mid/hindbrain boundary specific markers followed by the increase in expression of midbrain dopaminergic (mDA) neuronal markers compared to a mock control.   In contrast, high Wnt-1-expressing clones displayed different degrees of impaired neural differentiation. A detailed analysis revealed that those clones retained high expression levels of the pluripotent marker Oct3/4 when compared to low Wnt-.-expressing clones and control mESCs. Thus suggesting that persistent expression of pluripotent markers led to the lack of an efficient neural development. Additionally, high Wnt-1-expressing clones showed an increase in proliferation in an undifferentiated state. Taken together our findings imply that different levels of Wnt-1 expression can differently affect the neural potential of mESC. In conclusion, manipulation of Wnt-1 expression could be useful to set up strategies for the maintenance of undifferentiated ESC or to optimize protocols for the generation of mDA neurons from ESCs.