CDX2 dose-dependently influences the gene regulatory network underlying human extraembryonic mesoderm development

Area of Science:

• Developmental Biology
• Stem Cell Biology
• Genomics

Background:

• The transcription factor CDX2 is essential for early embryonic development, with its loss causing allantois defects.
• Understanding CDX2's role in gene regulation is crucial for deciphering extraembryonic mesoderm development.

Purpose of the Study:

• To investigate the dose-dependent effects of CDX2 on the gene regulatory network governing extraembryonic mesoderm development.
• To identify specific pathways regulated by CDX2 levels during early embryogenesis.

Main Methods:

• Engineered human induced pluripotent stem cells (hiPSCs) with varying CDX2 genotypes (wild-type, heterozygous, homozygous null).
• Differentiated hiPSCs in a 2D gastruloid model and performed single-nucleus RNA and ATAC sequencing (snRNA-seq and snATAC-seq).
• Compared gene expression profiles with TBXT-knockout hiPSCs to identify communally misregulated genes.

Main Results:

• CDX2 dose-dependently regulates key developmental pathways, including VEGF and non-canonical WNT signaling.
• Chromatin accessibility in heterozygous CDX2 cells resembles wild-type, indicating gene expression variability is not solely due to accessibility.
• Identified shared misregulated genes between CDX2 and TBXT loss-of-function, critical for cytoskeletal integrity and tissue permeability.

Conclusions:

• CDX2 dosage precisely controls gene expression in the extraembryonic mesoderm.
• The findings elucidate CDX2's role in vascular development and allantoic elongation, offering insights into developmental defects.