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Essigke, D.* ; Ilyaskin, A.V.* ; Wörn, M.* ; Bohnert, B.N. ; Xiao, M.* ; Daniel, C.* ; Amann, K.* ; Birkenfeld, A.L. ; Szabo, R.* ; Bugge, T.H.* ; Korbmacher, C.* ; Artunc, F.

Zymogen-locked mutant prostasin (Prss8) leads to incomplete proteolytic activation of the epithelial sodium channel (ENaC) and severely compromises triamterene tolerance in mice.

Acta Physiol., DOI: 10.1111/apha.13640 (2021)
Verlagsversion Forschungsdaten DOI
Open Access Gold (Paid Option)
Creative Commons Lizenzvertrag
AIM: The serine protease prostasin (Prss8) is expressed in the distal tubule and stimulates proteolytic activation of the epithelial sodium channel (ENaC) in co-expression experiments in vitro. The aim of this study was to explore the role of prostasin in proteolytic ENaC activation in the kidney in vivo. METHODS: We used genetically modified knockin mice carrying a Prss8 mutation abolishing proteolytic activity (Prss8-S238A) or a mutation leading to a zymogen-locked state (Prss8-R44Q). Mice were challenged with low sodium diet and diuretics. Regulation of ENaC activity by Prss8-S238A and Prss8-R44Q was studied in vitro using the Xenopus laevis oocyte expression system. RESULTS: Co-expression of murine ENaC with Prss8-wt or Prss8-S238A in oocytes caused maximal proteolytic ENaC activation, whereas ENaC was activated only partially in oocytes co-expressing Prss8-R44Q. This was paralleled by a reduced proteolytic activity at the cell surface of Prss8-R44Q expressing oocytes. Sodium conservation under low sodium diet was preserved in Prss8-S238A and Prss8-R44Q mice but with higher plasma aldosterone concentrations in Prss8-R44Q mice. Treatment with the ENaC inhibitor triamterene over four days was tolerated in Prss8-wt and Prss8-S238A mice, whereas Prss8-R44Q mice developed salt wasting and severe weight loss associated with hyperkalemia and acidosis consistent with impaired ENaC function and renal failure. CONCLUSION: Unlike proteolytically inactive Prss8-S238A, zymogen-locked Prss8-R44Q produces incomplete proteolytic ENaC activation in vitro and causes a severe renal phenotype in mice treated with the ENaC inhibitor triamterene. This indicates that Prss8 plays a role in proteolytic ENaC activation and renal function independent of its proteolytic activity.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Schlagwörter Enac ; Prostasin ; Prss8 ; Prss8-r44q ; Prss8-s238a ; Epithelial Sodium Channel; Gamma-subunit; Na+ Channel; Aldosterone; Cleavage; Localization; Proteases; Urine; Excretion; Abundance; Plasmin
ISSN (print) / ISBN 1748-1708
e-ISSN 1748-1716
Zeitschrift Acta Physiologica
Verlag Wiley
Verlagsort Hoboken
Begutachtungsstatus Peer reviewed
Förderungen National Institute of Dental and Craniofacial Research
Deutsche Forschungsgemeinschaft