Timing is everything: Reiterative Wnt, BMP and RA signaling regulate developmental competence during endoderm...

Area of Science:

• Developmental Biology
• Stem Cell Biology
• Molecular Embryology

Background:

• Organogenesis relies on conserved signaling pathways with stage-dependent effects.
• Understanding how cellular competence changes during development is crucial but poorly understood.

Purpose of the Study:

• Investigate the temporal regulation of endoderm developmental competence and organ induction, specifically respiratory fate.
• Examine the roles of Wnt, BMP, and retinoic acid (RA) signaling sequences in regulating these processes.

Main Methods:

• Utilized Xenopus, mouse, and human pluripotent stem cells.
• Analyzed the temporal sequence of Wnt, BMP, and RA signaling.
• Mapped the modulation of Wnt and BMP responses by RA across developmental stages.

Main Results:

• Lung developmental competence is established by the gastrula stage, influenced by Wnt/BMP anterior-posterior patterning.
• Early Wnt/BMP signaling renders posterior endoderm unresponsive to later lung induction cues.
• Retinoic acid (RA) exhibits temporal specificity, influencing posterior identity in gastrula and refining respiratory/gut fates in later stages.

Conclusions:

• Vertebrate endoderm exhibits a dynamic and conserved response to reiterative signaling during organogenesis.
• Early signaling events (Wnt/BMP/RA) critically dictate cellular responses to subsequent signals, regulating both competence and fate specification.