Conditional control of the differentiation competence of pancreatic endocrine and ductal cells by Fgf10

Area of Science:

• Developmental Biology
• Endocrinology
• Cell Signaling

Background:

• Fibroblast growth factor 10 (Fgf10) is crucial for mesenchymal-to-epithelial signaling in endodermal development.
• Fgf10 deficiency impairs pancreatic progenitor expansion, while ectopic expression causes progenitor arrest and hyperplasia.

Purpose of the Study:

• To investigate the impact of conditional Fgf10 gain-of-function on pancreatic progenitor cell competence.
• To determine the reversibility of Fgf10-induced progenitor arrest and its effect on terminal differentiation.
• To identify critical developmental windows for pancreatic cell lineage specification.

Main Methods:

• Utilized a conditional Fgf10 gain-of-function mouse model.
• Analyzed pancreatic progenitor cell behavior and differentiation potential at specific gestational time points.
• Examined gene expression markers including Ngn3, Ptf1a, and Bhlhb8.

Main Results:

• Fgf10-arrested pancreatic progenitors can resume terminal differentiation upon Fgf10 cessation, but competence is time-dependent.
• A critical window for endocrine and ductal cell fate competence exists between E13.5 and E15.5, coinciding with the secondary transition.
• Sustained Fgf10 expression during this window leads to irreversible loss of endocrine and ductal competence, possibly due to Ngn3 downregulation, while exocrine competence is maintained (Ptf1a dependent).

Conclusions:

• The timing of Fgf10 signaling dictates the competence of pancreatic progenitors for specific cell lineages.
• A defined developmental window exists for endocrine and ductal cell differentiation, closing during the secondary transition.
• Fgf10 signaling plays a critical role in establishing and maintaining these lineage-specific competence windows during pancreatic development.