Cyst growth in ADPKD is prevented by pharmacological and genetic inhibition of TMEM16A in vivo

Ines Cabrita,Björn Buchholz,Karl Kunzelmann,Kathrin Skoczynski,Andre Kraus,Julia Katharina Scholz,Rainer Schreiber

doi:10.1038/s41467-020-18104-5

Abstract

In autosomal dominant polycystic kidney disease (ADPKD) multiple bilateral renal cysts gradually enlarge, leading to a decline in renal function. Transepithelial chloride secretion through cystic fibrosis transmembrane conductance regulator (CFTR) and TMEM16A (anoctamin 1) are known to drive cyst enlargement. Here we demonstrate that loss of Pkd1 increased expression of TMEM16A and CFTR and Cl− secretion in murine kidneys, with TMEM16A essentially contributing to cyst growth. Upregulated TMEM16A enhanced intracellular Ca2+ signaling and proliferation of Pkd1-deficient renal epithelial cells. In contrast, increase in Ca2+ signaling, cell proliferation and CFTR expression was not observed in Pkd1/Tmem16a double knockout mice. Knockout of Tmem16a or inhibition of TMEM16A in vivo by the FDA-approved drugs niclosamide and benzbromarone, as well as the TMEM16A-specific inhibitor Ani9 largely reduced cyst enlargement and abnormal cyst cell proliferation. The present data establish a therapeutic concept for the treatment of ADPKD.

Highlights

In autosomal dominant polycystic kidney disease (ADPKD) multiple bilateral renal cysts gradually enlarge, leading to a decline in renal function
We previously demonstrated that blocking of TMEM16A inhibits plMDCK cyst growth in a collagen matrix[8,11]
Intracellular cAMP levels are enhanced in Pkd1−/− cells under control condition and are further enhanced after stimulation with a

Summary

Introduction

In autosomal dominant polycystic kidney disease (ADPKD) multiple bilateral renal cysts gradually enlarge, leading to a decline in renal function. Transepithelial chloride secretion through cystic fibrosis transmembrane conductance regulator (CFTR) and TMEM16A (anoctamin 1) are known to drive cyst enlargement. We demonstrate that loss of Pkd[1] increased expression of TMEM16A and CFTR and Cl− secretion in murine kidneys, with TMEM16A essentially contributing to cyst growth. Upregulated TMEM16A enhanced intracellular Ca2+ signaling and proliferation of Pkd1-deficient renal epithelial cells. Cell proliferation and fluid secretion are two essential characteristics of cyst development and enlargement. The Ca2+ activated Cl− channel TMEM16A is known to be essential for fluid secretion into renal cysts in vitro[7,8,9]. We use in vivo and in vitro models for ADPKD and unmask upregulation of expression of TMEM16A and CFTR in kidneys of Pkd1-knockout mice and Pkd1-knockout MDCK cells. The results demonstrate TMEM16A as a central pharmacological target to suppress cyst growth in ADPKD

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