Journal article

Cathepsin B increases ENaC activity leading to hypertension early in nephrotic syndrome

  • Larionov, Alexey Institute of Anatomy, Department of Medicine, University of Fribourg, Switzerland
  • Dahlke, Eileen Institute of Anatomy, Christian Albrechts‐University Kiel, Kiel, Germany
  • Kunke, Madlen Institute of Anatomy, Christian Albrechts‐University Kiel, Kiel, Germany
  • Rodriguez, Luis Zanon Institute of Anatomy, Christian Albrechts‐University Kiel, Kiel, Germany
  • Schiessl, Ina M. Institute of Physiology, University of Regensburg, Regensburg, Germany
  • Magnin, Jean‐Luc Service LaboratoireHôpital Fribourg, Switzerland
  • Kern, Ursula Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Germany
  • Alli, Abdel A. Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
  • Mollet, Geraldine Laboratory of Hereditary Kidney Diseases, INSERM UMR 1163, Université Paris Descartes, France
  • Schilling, Oliver Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Germany - BIOSS Center for Biological Signaling Studies, University of Freiburg, Germany
  • Castrop, Hayo Institute of Physiology, University of Regensburg, Regensburg, Germany
  • Theilig, Franziska Institute of Anatomy, Department of Medicine, University of Fribourg, Switzerland - Institute of Anatomy, Christian Albrechts‐University Kiel, Kiel, Germany
Show more…
    2019
Published in:
  • Journal of Cellular and Molecular Medicine. - 2019, vol. 23, no. 10, p. 6543–6553
English The NPHS2 gene, encoding the slit diaphragm protein podocin, accounts for genetic and sporadic forms of nephrotic syndrome (NS). Patients with NS often present symptoms of volume retention, such as oedema formation or hypertension. The primary dysregulation in sodium handling involves an inappropriate activation of the epithelial sodium channel, ENaC. Plasma proteases in a proteinuria‐dependent fashion have been made responsible; however, referring to the timeline of symptoms occurring and underlying mechanisms, contradictory results have been published. Characterizing the mouse model of podocyte inactivation of NPHS2 (Nphs2∆pod) with respect to volume handling and proteinuria revealed that sodium retention, hypertension and gross proteinuria appeared sequentially in a chronological order. Detailed analysis of Nphs2∆pod during early sodium retention, revealed increased expression of full‐length ENaC subunits and αENaC cleavage product with concomitant increase in ENaC activity as tested by amiloride application, and augmented collecting duct Na+/K+‐ATPase expression. Urinary proteolytic activity was increased and several proteases were identified by mass spectrometry including cathepsin B, which was found to process αENaC. Renal expression levels of precursor and active cathepsin B were increased and could be localized to glomeruli and intercalated cells. Inhibition of cathepsin B prevented hypertension. With the appearance of gross proteinuria, plasmin occurs in the urine and additional cleavage of γENaC is encountered. In conclusion, characterizing the volume handling of Nphs2∆pod revealed early sodium retention occurring independent to aberrantly filtered plasma proteases. As an underlying mechanism cathepsin B induced αENaC processing leading to augmented channel activity and hypertension was identified.
Faculty
Faculté des sciences et de médecine
Department
Département de Médecine
Language
  • English
Classification
Biology
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/308242
Statistics

Document views: 6 File downloads:
  • lar_cbi.pdf: 1