Loss of PKD1 and PKD2 share common effects on intracellular Ca²⁺ signaling

Area of Science:

• Nephrology
• Cell Biology
• Molecular Medicine

Background:

• Autosomal dominant polycystic kidney disease (ADPKD) involves renal cyst enlargement and function decline.
• Transepithelial chloride secretion via CFTR and TMEM16A drives cyst growth.
• Loss of PKD1 increases TMEM16A expression and function, promoting cyst enlargement via calcium signaling.

Purpose of the Study:

• To investigate the impact of PKD2 loss-of-function on calcium signaling in renal epithelial cells.
• To determine if TMEM16A inhibition is a viable therapeutic strategy for ADPKD caused by PKD2 mutations.

Main Methods:

• Knockdown of Pkd2 in mouse primary renal epithelial cells using viral shRNA transfection.
• Analysis of intracellular calcium (Ca2+) signaling, including basal Ca2+, store-operated Ca2+ entry, and purinergic Ca2+ store release.
• Comparison of cellular responses in Pkd2-knockdown cells versus Pkd1-/- cells.

Main Results:

• PKD2 knockdown reduced basal Ca2+ and increased store-operated Ca2+ entry, independent of TMEM16A.
• Disease-causing purinergic Ca2+ store release was enhanced in Pkd2-knockdown cells, similar to Pkd1-/- cells.
• These findings suggest TMEM16A's role in ADPKD pathogenesis extends to PKD2 mutations.

Conclusions:

• Pharmacological inhibition of TMEM16A is a potential therapeutic approach for ADPKD resulting from mutations in both PKD1 and PKD2.
• Understanding the distinct calcium signaling pathways affected by PKD1 and PKD2 loss is crucial for targeted ADPKD therapies.