Investigating the Role of Podocalyxin in Hematoendothelial Progenitor Development in the Chick Embryo

Parveen, Fabbiha (2025) Investigating the Role of Podocalyxin in Hematoendothelial Progenitor Development in the Chick Embryo. Masters thesis, University of East Anglia.

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Abstract

The extracellular matrix (ECM) plays a critical role in regulating cell fate decisions during early embryonic development. Hematoendothelial progenitors (HEPs) arise from the lateral plate mesoderm and give rise to both endothelial and hematopoietic lineages. Podocalyxin (PODXL) is an ECM-associated transmembrane protein implicated in cell adhesion, polarity, and migration; however, its role during early hematoendothelial development remains poorly understood.

In this study, we focus on characterizing the spatial and temporal expression of Podxl, during chick embryogenesis and to investigate its functional role during early hematoendothelial development. We also focused on its relationship with Tal1, a well- known hematopoietic transcription factor.

Through hybridization chain reaction (HCR) experiments, the spatial expression of Podxl and Tal1 was analysed across key Hamburger- Hamilton (HH) stages. emerging from the LPM, where HEP cells reside. Splice-blocking morpholino’s were used to knock down PODXL to perform functional analyses. PODXL expression was detected in the lateral plate mesoderm and developing cardiac regions during early embryogenesis, partially overlapping with Tal1 expression. Following Podxl knockdown, 46% of embryos exhibited heart looping defects and 15.3% displayed cardia bifida, indicating a requirement for Podxl in normal cardiac morphogenesis.

To elucidate regulatory mechanisms, enhancers of PODXL were cloned and injected into chick embryos. Selected based on single-cell data, several enhancers displayed strong tissue-specific activity in the lateral plate mesoderm, dorsal aorta, endothelium, and cardiac regions, indicating their role in driving PODXL expression during hematoendothelial and cardiovascular development.

These findings suggest that PODXL may influence hematoendothelial development indirectly by modulating the cellular microenvironment rather than acting as a direct regulator of Tal1 expression.

Overall, this study identifies Podocalyxin as an important ECM-associated factor during early chick development and provides a foundation for future studies investigating its mechanistic role in hematoendothelial lineage specification and cardiovascular development.

Item Type:	Thesis (Masters)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Chris White
Date Deposited:	21 May 2026 10:09
Last Modified:	21 May 2026 10:09
URI:	https://ueaeprints.uea.ac.uk/id/eprint/103124
DOI:

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