Abstract
Abstract: :
Purpose: We have previously shown that BMP signaling regulate the neural potential of adult corneal stem cells/progenitors (Zhao et al., Dev Biol, 2002). Since Wnt signaling is known to regulate the maintenance of ectodermal stem cells in general, we are interested in knowing if Wnt and BMP signaling interact during the acquisition of neural potential by corneal stem cells/progenitors in vitro. Methods: The expression of components of Wnt canonical pathway (i.e., Wnt proteins, Frizzled receptors, Lef1) and the regulators (i.e., sFRPs and DKKs ) were examined by RT–PCR analysis of limbal corneal epithelial cell dissociates in the presence or absence of mitogens/BMP4/Noggin. Cell proliferation and acquisition of neural properties were analyzed by immunocytochemistry and RT–PCR analysis carried out on cells exposed to Wnt3a / Fzd8CRD (negative regulator of Wnt–Frizzled interactions). Results: Transcripts corresponding to different components of Wnt canonical pathway such as Wnt proteins, Frizzled receptors, Lef1 and modulators such as sFRPs and DKKs were detected in corneal stem cells/progenitors in vitro. Levels of several of these component transcripts were observed to be increased in the presence of BMP4 in comparison to those in the presence of BMP4+Noggin. We are currently investigating the effect of Wnt signaling on neural potential of corneal stem cells/progenitors by accentuating and inhibiting the Wnt canonical pathway. Conclusions: Our results suggest that both Wnt and BMP signaling regulate neural potential of corneal stem cells/progenitors in vitro.
Keywords: retinal development • proliferation • cell–cell communication