Vacuolar ATPase regulates ureteric bud branching morphogenesis during kidney development

Area of Science:

• Developmental Biology
• Cell Physiology
• Renal Biology

Background:

• Ureteric bud (UB) branching is crucial for kidney development.
• The prorenin receptor (PRR/ATP6AP2), a subunit of vacuolar H+-ATPase (V-ATPase), is vital for normal UB branching.
• The role of V-ATPase activity, acidosis, and intracellular pH (pHi) in UB branching requires further investigation.

Purpose of the Study:

• To investigate the hypothesis that V-ATPase activity, acidosis, and UB cell intracellular pH regulate UB branching morphogenesis.
• To determine the effects of V-ATPase inhibition and acidosis on UB branching and cell migration.

Main Methods:

• Ex vivo culture of E12.5 mouse kidneys with time-lapse microscopy.
• In vitro transwell migration assays for UB cells.
• Intracellular pH (pHi) measurements using pH indicators.
• Induction of hypercapnic and metabolic acidosis.

Main Results:

• V-ATPase inhibition with Bafilomycin reduced UB cell migration in vitro.
• Bafilomycin treatment, hypercapnic acidosis, and metabolic acidosis significantly reduced UB branching in cultured kidneys.
• Acidosis conditions led to a marked reduction in the number of UB tips.

Conclusions:

• Intact V-ATPase activity is essential for normal ureteric bud branching during kidney development.
• V-ATPase-dependent reduction in UB cell intracellular pH likely impairs branching by inhibiting cell migration.
• Acidosis negatively impacts kidney development by disrupting UB branching morphogenesis.