Mannan-binding lectin serine protease-2 (MASP-2) in human kidney and its relevance for proteolytic activation of the epithelial sodium channel

Rikke Zachar*, Steffen Thiel, Søren Hansen, Maiken Lumby Henriksen, Mikkel Ole Skjoedt, Karsten Skjodt, Zohra Hamzaei, Kirsten Madsen, Lars Lund, Edith Hummler, Per Svenningsen, Boye Lagerbon Jensen

*Corresponding author for this work

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Proteolytic activation of the renal epithelial sodium channel (ENaC) is increased by aldosterone. The aldosterone-sensitive protease remains unidentified. In humans, elevated circulating aldosterone is associated with increased urinary extracellular vesicle (uEVs) excretion of mannan-binding lectin associated serine protease-2 (MASP-2). We hypothesized that MASP-2 is a physiologically relevant ENaC-activating protease. It was confirmed that MASP2 mRNA is abundantly present in liver but not in human and mouse kidneys. Aldosterone-stimulation of murine cortical colleting duct (mCCD) cells did not induce MASP-2 mRNA. In human kidney collecting duct, MASP-2 protein was detected in AQP2-negative/ATP6VB1-positive intercalated cells suggestive of MASP2 protein uptake. Plasma concentration of full-length MASP-2 and the short splice variant MAp19 were not changed in a cross-over intervention study in healthy humans with low (70 mmol/day) versus high (250 mmol/day) Na+ intake despite changes in aldosterone. The ratio of MAp19/MASP-2 in plasma was significantly increased with a high Na+ diet and the ratio correlated with changes in aldosterone and fractional Na+ excretion. MASP-2 was not detected in crude urine or in uEVs. MASP2 activated an amiloride-sensitive current when co-expressed with ENaC in Xenopus oocytes, but not when added to the bath solution. In monolayers of collecting duct M1 cells, MASP2 expression did not increase amiloride-sensitive current and in HEK293 cells, MASP-2 did not affect γENaC cleavage. MASP-2 is neither expressed nor co-localized and co-regulated with ENaC in the human kidney or in urine after low Na+ intake. MASP-2 does not mediate physiological ENaC cleavage in low salt/high aldosterone settings.

Original languageEnglish
Article number15955
JournalScientific Reports
Number of pages13
Publication statusPublished - 24. Sep 2022

Bibliographical note

Publisher Copyright:
© 2022, The Author(s).


  • Aldosterone/metabolism
  • Amiloride/pharmacology
  • Animals
  • Aquaporin 2/metabolism
  • Epithelial Sodium Channels/metabolism
  • HEK293 Cells
  • Humans
  • Kidney Tubules, Collecting/metabolism
  • Kidney/metabolism
  • Mannose-Binding Protein-Associated Serine Proteases/metabolism
  • Mice
  • RNA, Messenger/metabolism
  • Sodium/metabolism


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