Inhibition of the TRPC5 ion channel protects the kidney filter
Thomas Schaldecker, … , Astrid Weins, Anna Greka
Thomas Schaldecker, … , Astrid Weins, Anna Greka
Published November 15, 2013
Citation Information: J Clin Invest. 2013;123(12):5298-5309. https://doi.org/10.1172/JCI71165.
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Research Article Nephrology

Inhibition of the TRPC5 ion channel protects the kidney filter

Abstract

An intact kidney filter is vital to retention of essential proteins in the blood and removal of waste from the body. Damage to the filtration barrier results in albumin loss in the urine, a hallmark of cardiovascular disease and kidney failure. Here we found that the ion channel TRPC5 mediates filtration barrier injury. Using Trpc5-KO mice, a small-molecule inhibitor of TRPC5, Ca2+ imaging in isolated kidney glomeruli, and live imagining of podocyte actin dynamics, we determined that loss of TRPC5 or its inhibition abrogates podocyte cytoskeletal remodeling. Inhibition or loss of TRPC5 prevented activation of the small GTP-binding protein Rac1 and stabilized synaptopodin. Importantly, genetic deletion or pharmacologic inhibition of TRPC5 protected mice from albuminuria. These data reveal that the Ca2+-permeable channel TRPC5 is an important determinant of albuminuria and identify TRPC5 inhibition as a therapeutic strategy for the prevention or treatment of proteinuric kidney disease.

Authors

Thomas Schaldecker, Sookyung Kim, Constantine Tarabanis, Dequan Tian, Samy Hakroush, Philip Castonguay, Wooin Ahn, Hanna Wallentin, Hans Heid, Corey R. Hopkins, Craig W. Lindsley, Antonio Riccio, Lisa Buvall, Astrid Weins, Anna Greka

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Figure 5

Real-time imaging revealed the dynamics of TRPC5 inhibition on PS-induced actin remodeling.

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Real-time imaging revealed the dynamics of TRPC5 inhibition on PS-induce...
LifeAct technology and confocal microscopy were used to assay the timing and severity of cytoskeletal remodeling in the presence of PS. PS induced increased ruffling activity and lamellipodia formation within 13 minutes of its initial application. By 28 minutes, actin stress fibers were disrupted and no longer extended across the span of the cell’s cytoplasm, as they did before PS application. This cytoskeletal remodeling resulted in the involution of the cell onto itself after 34 minutes, with the appearance of an intensely fluorescent structure at the center of a previously healthy podocyte. This PS-mediated actin remodeling was blocked by 10 μM ML204, resulting in the preservation of stress fibers and the cell’s cytoskeleton throughout the same time frame. Representative images are shown (see Supplemental Video 1). Original magnification, ×400.