Stromal-epithelial crosstalk regulates kidney progenitor cell differentiation

Area of Science:

• Developmental biology
• Renal physiology
• Cell signaling

Background:

• Kidney epithelial progenitor fate was thought to be solely regulated by ureteric bud signals.
• Wnt9b, a ureteric bud factor, was known to drive both progenitor renewal and differentiation.
• The mechanism by which Wnt9b induces opposing cellular processes remained unclear.

Purpose of the Study:

• To investigate the cooperative signaling between ureteric bud and stromal cells in kidney progenitor regulation.
• To identify the stromal factors involved in modulating Wnt9b's effect on nephron progenitor differentiation.
• To elucidate the signaling balance regulating kidney size and function.

Main Methods:

• Investigated signaling interactions between ureteric bud and stromal fibroblasts in kidney development.
• Utilized genetic and molecular approaches to analyze the role of Wnt9b and Fat4.
• Examined the impact of stromal signals on nephron progenitor renewal and differentiation.

Main Results:

• Stromal fibroblast signals cooperate with Wnt9b to promote nephron progenitor differentiation.
• The atypical cadherin Fat4 encodes a key stromal signal involved in this process.
• A balance of opposing signals from ureteric bud and stroma is crucial for regulating progenitor fate.

Conclusions:

• Kidney progenitor fate is regulated by a balance of signals from both the ureteric bud and stromal compartments.
• Wnt9b and stromal signals, including Fat4, orchestrate the opposing processes of progenitor renewal and differentiation.
• This balanced signaling is essential for establishing proper kidney size and function.