ΔNP63 regulates epithelial stratification and differentiation in the murine ureter

Area of Science:

• Urothelial biology
• Developmental biology
• Epithelial cell differentiation

Background:

• The urothelium, a specialized stratified epithelium, lines the urinary tract.
• Its layered cytoarchitecture (basal, intermediate, superficial cells) develops from precursor cells.
• The precise mechanisms governing this development are not fully understood.

Purpose of the Study:

• To investigate the role of the transcription factor delta N p63 (ΔNP63) in murine ureter urothelial development.
• To elucidate the cellular and molecular functions of ΔNP63 in establishing urothelial cytoarchitecture.

Main Methods:

• Analysis of ΔNP63 expression patterns in murine ureter epithelial progenitors during embryonic development (starting E14.5).
• Conditional knockout mouse models to study the effects of ΔNp63 loss on ureteric urothelium.
• Gene expression analysis to identify molecular pathways affected by ΔNP63 deficiency.

Main Results:

• ΔNP63 is expressed in basal and intermediate urothelial cells from late fetal stages.
• Conditional loss of ΔNp63 results in a monolayer of partially differentiated superficial cells around birth.
• Genes for cell adhesion, stratification, and B/I cell differentiation were downregulated; Ihh expression and lamina propria formation were premature.
• Urothelial cytoarchitecture was gradually restored postnatally by remaining ΔNP63+ progenitors.

Conclusions:

• A conserved ΔNP63 gene regulatory module is essential for urothelial stratification and differentiation of basal/intermediate cells.
• ΔNP63 controls timely lamina propria development in the fetal ureter.
• Residual ΔNP63-expressing progenitors can drive urothelial reconstitution after birth.