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Analysis of the polarized expression of Wnt/ß-catenin pathway and Coup-tf2 in embryoid bodies derived from embryonic stem cells

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Aline Mika Matsuguma
Total Authors: 1
Document type: Master's Dissertation
Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
Defense date:
Examining board members:
Katlin Brauer Massirer; Hozana Andrade Castillo
Advisor: Henrique Marques Barbosa de Souza

Gastrulation is an important event during embryonic development, in which the embryo originates three germ layers: ectoderm, mesoderm and endoderm. This process is organized by several signaling pathways that are differentially expressed, culminating in the patterning of the embryo. The Wnt/ß-catenin signaling pathway is important for the proper gastrulation. This pathway is patterned as a gradient resulting in a polarized embryo. During gastrulation, Wnt/ß-catenin signaling pathway segregates the ectoderm from the mesendoderm, then it regulates the mesoderm and endoderm formation. The Wnt/ß-catenin pathway is known to be polarized both in mice embryos and embryoid bodies (EB). Previous studies from our group showed that COUP-TF2, a transcription factor known to regulate cell fate decisions, is polarized in mice EB, resembling the Wnt/-ßcatenin pathway polarized pattern. Thus, we were interested in investigating the role of COUP-TF2 in germ layer differentiation in EB in the context of gastrulation. Our results showed that mice embryonic stem cells treated with 4MNol, a molecule that inactivates COUP-TF2, led to reduced expression of mesodermal (Bra(T)) and endodermal (Foxa2) markers. However, gene expression analysis of Axin2, a Wnt/ß-catenin pathway target gene, showed no regulation of this pathway, suggesting that COUP-TF2 does not regulate Wnt/ß-catenin signaling. Additionally, we showed that Wnt/-ß-catenin signaling modulation does not regulate Coup-tf2 expression in human EB. however, exploratory analysis of Wnt-segregated cell populations from human EB, suggested that Coup-tf2 is more expressed in Wnt-positive cells when compared to Wnt-negative cells, indicating that Coup-tf2 might have a role in mesoderm-endoderm segregation. Gene expression analysis in Coup-tf2 knockout mice EB showed that Coup-tf2 does not regulate mesoderm and endoderm formation, indicating that the regulation observed in the 4MNol treatment might be a consequence of non-specific action of 4MNol that could lead to impaired mesoderm and endoderm formation. This study showed that Coup-tf2 does not regulate germ layer formation during gastrulation in mice EB. However, Coup-tf2 might have a role in the following step, during mesendodermal differentiation in mesoderm and endoderm (AU)

FAPESP's process: 16/13095-8 - Characterization of the relationship between the polarized expression of COUP-TFII and the Wnt/²-catenin pathway in embryoid bodies from murine embryonic stem cells
Grantee:Aline Mika Matsuguma
Support Opportunities: Scholarships in Brazil - Master