Plasma kallikrein activates the epithelial sodium channel in vitro but is not essential for volume retention in nephrotic mice.

Härteis S, Schork A, Doerffel T, Bohnert BN, Nacken R, Woern M, Xiao M, Essigke D, Janessa A, Schmaier AH, Feener EP, Haering HU, Bertog M, Korbmacher C, Artunc F (2018)

Publication Type: Journal article

Publication year: 2018

Journal

Book Volume: 224

Pages Range: e13060

Journal Issue: 1

DOI: 10.1111/apha.13060

Abstract

AIM: Recent work has demonstrated that activation of the epithelial sodium channel (ENaC) by aberrantly filtered serine proteases causes sodium retention in nephrotic syndrome. The aim of this study was to elucidate a potential role of plasma kallikrein (PKLK) as a candidate serine protease in this context. METHODS: We analysed PKLK in the urine of patients with chronic kidney disease (CKD, n = 171) and investigated its ability to activate human ENaC expressed in Xenopus laevis oocytes. Moreover, we studied sodium retention in PKLK-deficient mice (klkb1-/- ) with experimental nephrotic syndrome induced by doxorubicin injection. RESULTS: In patients with CKD, we found that PKLK is excreted in the urine up to a concentration of 2 μg mL-1 which was correlated with albuminuria (r = .71) and overhydration as assessed by bioimpedance spectroscopy (r = .44). PKLK increased ENaC-mediated whole-cell currents, which was associated with the appearance of a 67 kDa γ-ENaC cleavage product at the cell surface consistent with proteolytic activation. Mutating a putative prostasin cleavage site in γ-ENaC prevented channel stimulation by PKLK. In a mouse model for nephrotic syndrome, active PKLK was present in nephrotic urine of klkb1+/+ but not of klkb1-/- mice. However, klkb1-/- mice were not protected from ENaC activation and sodium retention compared to nephrotic klkb1+/+ mice. CONCLUSION: Plasma kallikrein is detected in the urine of proteinuric patients and mice and activates ENaC in vitro involving the putative prostasin cleavage site. However, PKLK is not essential for volume retention in nephrotic mice.

Authors with CRIS profile

Involved external institutions

University Hospitals of Cleveland / Case Western Reserve University Hospital United States (USA) (US) Veterans Affairs Healthcare System Boston and Harvard Medical School United States (USA) (US) Universitätsklinikum Tübingen Germany (DE)

How to cite

APA:

Härteis, S., Schork, A., Doerffel, T., Bohnert, B.N., Nacken, R., Woern, M.,... Artunc, F. (2018). Plasma kallikrein activates the epithelial sodium channel in vitro but is not essential for volume retention in nephrotic mice. Acta Physiologica, 224(1), e13060. https://doi.org/10.1111/apha.13060

MLA:

Härteis, Silke, et al. "Plasma kallikrein activates the epithelial sodium channel in vitro but is not essential for volume retention in nephrotic mice." Acta Physiologica 224.1 (2018): e13060.

BibTeX: Download