Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Angiotensinogen and C3 compete for renin-induced complement activation

Kristoffersson, Ann-Charlotte LU ; Sköld, Albin LU ; Welinder, Charlotte LU ; Wendler, Markus LU orcid ; Kalliokoski, Gabriella LU ; Bekassy, Zivile LU and Karpman, Diana LU orcid (2025) In Frontiers in Immunology 16.
Abstract

Renin from plasma, kidney, and recombinant sources was previously demonstrated to cleave C3 to C3a and C3b. C3a was generated at a similar rate to that by C3 convertase, and C3 cleavage was inhibited by the renin inhibitor aliskiren. Renin endogenously produced by Calu6 cells also led to C3 deposition on cells. These results have been challenged by another group suggesting that recombinant renin does not cleave C3 or that renin was contaminated by trypsin, which also cleaves C3. Here, we investigated C3 cleavage by recombinant renin and competitive inhibition in the presence of angiotensinogen. Recombinant renin was analyzed by mass spectrometry using endopeptidase LysC digestion and did not contain trypsin. C3 cleavage, using our... (More)

Renin from plasma, kidney, and recombinant sources was previously demonstrated to cleave C3 to C3a and C3b. C3a was generated at a similar rate to that by C3 convertase, and C3 cleavage was inhibited by the renin inhibitor aliskiren. Renin endogenously produced by Calu6 cells also led to C3 deposition on cells. These results have been challenged by another group suggesting that recombinant renin does not cleave C3 or that renin was contaminated by trypsin, which also cleaves C3. Here, we investigated C3 cleavage by recombinant renin and competitive inhibition in the presence of angiotensinogen. Recombinant renin was analyzed by mass spectrometry using endopeptidase LysC digestion and did not contain trypsin. C3 cleavage, using our protocol and that of the other group, showed cleavage to C3b by immunoblotting. Cleavage was inhibited by aliskiren, which inhibits renin but not trypsin. Cleavage to C3a occurred within 1 min as detected by enzyme-linked immunosorbent assay (ELISA). Angiotensinogen competed for renin-mediated C3 cleavage and inhibited C3a generation, but C3 did not inhibit cleavage of angiotensinogen to angiotensin I (detected by ELISA). The results suggest that renin cleaves C3 but angiotensinogen is its preferred substrate. The interaction between renin and C3 may gain importance in the kidney where renin concentrations are considerably higher than in the circulation and when the primary substrate, angiotensinogen, is cleaved and thereby depleted.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Angiotensinogen/metabolism, Renin/metabolism, Humans, Complement Activation/immunology, Complement C3/metabolism, Amides/pharmacology, Recombinant Proteins/metabolism, Complement C3a/metabolism, Fumarates/pharmacology
in
Frontiers in Immunology
volume
16
article number
1563868
publisher
Frontiers Media S. A.
external identifiers
  • scopus:105003204821
  • pmid:40242769
ISSN
1664-3224
DOI
10.3389/fimmu.2025.1563868
language
English
LU publication?
yes
additional info
Copyright © 2025 Kristoffersson, Sköld, Welinder, Wendler, Kalliokoski, Bekassy and Karpman.
id
f4843e17-2771-4f8c-9c89-62539a9427c8
date added to LUP
2025-04-29 12:48:31
date last changed
2025-07-09 10:43:13
@article{f4843e17-2771-4f8c-9c89-62539a9427c8,
  abstract     = {{<p>Renin from plasma, kidney, and recombinant sources was previously demonstrated to cleave C3 to C3a and C3b. C3a was generated at a similar rate to that by C3 convertase, and C3 cleavage was inhibited by the renin inhibitor aliskiren. Renin endogenously produced by Calu6 cells also led to C3 deposition on cells. These results have been challenged by another group suggesting that recombinant renin does not cleave C3 or that renin was contaminated by trypsin, which also cleaves C3. Here, we investigated C3 cleavage by recombinant renin and competitive inhibition in the presence of angiotensinogen. Recombinant renin was analyzed by mass spectrometry using endopeptidase LysC digestion and did not contain trypsin. C3 cleavage, using our protocol and that of the other group, showed cleavage to C3b by immunoblotting. Cleavage was inhibited by aliskiren, which inhibits renin but not trypsin. Cleavage to C3a occurred within 1 min as detected by enzyme-linked immunosorbent assay (ELISA). Angiotensinogen competed for renin-mediated C3 cleavage and inhibited C3a generation, but C3 did not inhibit cleavage of angiotensinogen to angiotensin I (detected by ELISA). The results suggest that renin cleaves C3 but angiotensinogen is its preferred substrate. The interaction between renin and C3 may gain importance in the kidney where renin concentrations are considerably higher than in the circulation and when the primary substrate, angiotensinogen, is cleaved and thereby depleted.</p>}},
  author       = {{Kristoffersson, Ann-Charlotte and Sköld, Albin and Welinder, Charlotte and Wendler, Markus and Kalliokoski, Gabriella and Bekassy, Zivile and Karpman, Diana}},
  issn         = {{1664-3224}},
  keywords     = {{Angiotensinogen/metabolism; Renin/metabolism; Humans; Complement Activation/immunology; Complement C3/metabolism; Amides/pharmacology; Recombinant Proteins/metabolism; Complement C3a/metabolism; Fumarates/pharmacology}},
  language     = {{eng}},
  month        = {{04}},
  publisher    = {{Frontiers Media S. A.}},
  series       = {{Frontiers in Immunology}},
  title        = {{Angiotensinogen and C3 compete for renin-induced complement activation}},
  url          = {{http://dx.doi.org/10.3389/fimmu.2025.1563868}},
  doi          = {{10.3389/fimmu.2025.1563868}},
  volume       = {{16}},
  year         = {{2025}},
}