Role of fibroblast growth factor signaling during proepicardium formation in the chick embryo

Area of Science:

• Developmental biology
• Cardiovascular research
• Cell signaling

Background:

• The proepicardium is a transient structure at the embryonic heart's venous pole.
• It serves as a source for multiple mature heart cell types.
• The role of fibroblast growth factors (FGFs) in its development is not fully understood.

Purpose of the Study:

• To investigate the function of FGF signaling in proepicardium formation.
• To determine the impact of FGFs on proepicardium cell proliferation, survival, and gene expression.

Main Methods:

• Expression analysis of FGF ligands and receptors in the embryonic chick proepicardium.
• Experimental modulation of FGF signaling using explant cultures and in vivo studies.
• Assessment of cell proliferation, survival, and expression of specific marker genes (Tbx18, Wt1, Tbx5).

Main Results:

• FGF ligands and receptors are expressed in the proepicardium.
• FGF signaling inhibition reduced cell proliferation and survival in explant cultures.
• In vivo, FGF inhibition impaired proepicardium villous outgrowth but maintained Tbx18 expression.
• Expression of Tbx18, Wt1, and Tbx5 remained unaffected by FGF inhibition.

Conclusions:

• FGFs act as autocrine or paracrine factors essential for proepicardium cell proliferation, survival, and villous outgrowth.
• FGF signaling is not required for the induction or maintenance of proepicardium-specific gene expression.