Interactions between the kallikrein-kinin system, the complement system and extracellular vesicles in vascular inflammation
(2025) In Lund University, Faculty of Medicine Doctoral Dissertation Series- Abstract
- The aim of this thesis was to investigate the interactions between the kallikrein-kinin system (KKS) and the complement system during vascular inflammation and the contribution of extracellular vesicles (EVs). Vasculitis, in patients and in experimental models, was studied as a prototype inflammatory disease of the vasculature.
Papers I and II addressed the impact KKS signalling has on complement activation. In Paper I vasculitis patient plasma was shown to have increased levels of endothelial-derived EVs bearing deposits of complement C3 and C9. Patient plasma induced complement deposition on endothelial EVs in a perfusion system. Kinin B1 and B2 receptor antagonists or C1 inhibitor reduced complement deposition. Similar effects were... (More) - The aim of this thesis was to investigate the interactions between the kallikrein-kinin system (KKS) and the complement system during vascular inflammation and the contribution of extracellular vesicles (EVs). Vasculitis, in patients and in experimental models, was studied as a prototype inflammatory disease of the vasculature.
Papers I and II addressed the impact KKS signalling has on complement activation. In Paper I vasculitis patient plasma was shown to have increased levels of endothelial-derived EVs bearing deposits of complement C3 and C9. Patient plasma induced complement deposition on endothelial EVs in a perfusion system. Kinin B1 and B2 receptor antagonists or C1 inhibitor reduced complement deposition. Similar effects were found using C1 inhibitor-depleted plasma in which the KKS is activated. In Paper II the effect of KKS activation, by kaolin or factor XIIa, was studied directly on ADP-preactivated glomerular endothelial cells showing that complement factors C3a, Ba, C5b-9 were released from or deposited on cell lysates. These effects were inhibited by a B1 receptor antagonist. The B1 receptor is a G protein coupled receptor, and we could show that the effects were mediated via the intracellular inositol triphosphate receptor. Furthermore, in Papers I and II mice were treated with a B1 receptor antagonist, or lacked the B1 and B2 receptor, and both papers showed that complement deposition in glomeruli was reduced under these conditions suggesting that signaling via these kinin receptors contributes to complement activation.
In Paper III we found that vasculitis patients have high levels of leukocyte-derived EVs bearing the B1 receptor. The receptor was shown to be transferred between cells by EVs. This was demonstrated using transfected cells but also native leukocyte-derived EVs. Importantly, the transferred B1 receptor was functional. In patient biopsies we identified leukocyte-derived B1 receptor-positive EVs docking onto glomerular endothelial cells, suggesting that the transfer of the B1 receptor to glomerular endothelial cells by EVs may occur in vivo and thereby induce kidney inflammation.
In Paper IV we show that kallikrein cleaves all components of C5b-9 in pure form, in the absence of plasma. In plasma, particularly C1 inhibitor-depleted plasma, kallikrein cleaved C5b, C6 and C7. The physiological significance of kallikrein activity was reduced formation of the membrane attack complex on rabbit red blood cells, and thus less hemolysis, and decreased deposition of C5b-9 on glomerular endothelial cells. Specificity of the enzymatic effect was demonstrated by using a monoclonal antibody against kallikrein, lanadelumab.
We demonstrate both activating and inhibitory interactions between the KKS and the complement system. In addition, circulating EVs are increased in patients with vasculitis, and they bear both complement components and the B1 receptor. These may be critical features during inflammation. The interactions between the KKS and complement could be of importance for treatment of inflammatory disorders.
(Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/fbbff4c8-b44b-49f1-899f-a9d4df1af616
- author
- Lopatko Fagerström, Ingrid LU
- supervisor
-
- Diana Karpman LU
- Zivile Bekassy LU
- opponent
-
- Professor Zipfel, Peter, Infection biology, Friedrich-Schiller-University, Jena
- organization
- publishing date
- 2025
- type
- Thesis
- publication status
- published
- subject
- keywords
- inflammation, kallikrein-kinin system, complement, kallikrein, extracellular vesicles
- in
- Lund University, Faculty of Medicine Doctoral Dissertation Series
- issue
- 2025:31
- pages
- 96 pages
- publisher
- Lund University, Faculty of Medicine
- defense location
- Belfragesalen, BMC D15, Klinikgatan 32 i Lund
- defense date
- 2025-04-04 13:00:00
- ISSN
- 1652-8220
- ISBN
- 978-91-8021-684-5
- language
- English
- LU publication?
- yes
- id
- fbbff4c8-b44b-49f1-899f-a9d4df1af616
- date added to LUP
- 2025-03-04 12:44:00
- date last changed
- 2025-04-04 13:53:46
@phdthesis{fbbff4c8-b44b-49f1-899f-a9d4df1af616,
abstract = {{The aim of this thesis was to investigate the interactions between the kallikrein-kinin system (KKS) and the complement system during vascular inflammation and the contribution of extracellular vesicles (EVs). Vasculitis, in patients and in experimental models, was studied as a prototype inflammatory disease of the vasculature.<br/>Papers I and II addressed the impact KKS signalling has on complement activation. In Paper I vasculitis patient plasma was shown to have increased levels of endothelial-derived EVs bearing deposits of complement C3 and C9. Patient plasma induced complement deposition on endothelial EVs in a perfusion system. Kinin B1 and B2 receptor antagonists or C1 inhibitor reduced complement deposition. Similar effects were found using C1 inhibitor-depleted plasma in which the KKS is activated. In Paper II the effect of KKS activation, by kaolin or factor XIIa, was studied directly on ADP-preactivated glomerular endothelial cells showing that complement factors C3a, Ba, C5b-9 were released from or deposited on cell lysates. These effects were inhibited by a B1 receptor antagonist. The B1 receptor is a G protein coupled receptor, and we could show that the effects were mediated via the intracellular inositol triphosphate receptor. Furthermore, in Papers I and II mice were treated with a B1 receptor antagonist, or lacked the B1 and B2 receptor, and both papers showed that complement deposition in glomeruli was reduced under these conditions suggesting that signaling via these kinin receptors contributes to complement activation.<br/>In Paper III we found that vasculitis patients have high levels of leukocyte-derived EVs bearing the B1 receptor. The receptor was shown to be transferred between cells by EVs. This was demonstrated using transfected cells but also native leukocyte-derived EVs. Importantly, the transferred B1 receptor was functional. In patient biopsies we identified leukocyte-derived B1 receptor-positive EVs docking onto glomerular endothelial cells, suggesting that the transfer of the B1 receptor to glomerular endothelial cells by EVs may occur in vivo and thereby induce kidney inflammation.<br/>In Paper IV we show that kallikrein cleaves all components of C5b-9 in pure form, in the absence of plasma. In plasma, particularly C1 inhibitor-depleted plasma, kallikrein cleaved C5b, C6 and C7. The physiological significance of kallikrein activity was reduced formation of the membrane attack complex on rabbit red blood cells, and thus less hemolysis, and decreased deposition of C5b-9 on glomerular endothelial cells. Specificity of the enzymatic effect was demonstrated by using a monoclonal antibody against kallikrein, lanadelumab.<br/>We demonstrate both activating and inhibitory interactions between the KKS and the complement system. In addition, circulating EVs are increased in patients with vasculitis, and they bear both complement components and the B1 receptor. These may be critical features during inflammation. The interactions between the KKS and complement could be of importance for treatment of inflammatory disorders.<br/>}},
author = {{Lopatko Fagerström, Ingrid}},
isbn = {{978-91-8021-684-5}},
issn = {{1652-8220}},
keywords = {{inflammation, kallikrein-kinin system, complement, kallikrein, extracellular vesicles}},
language = {{eng}},
number = {{2025:31}},
publisher = {{Lund University, Faculty of Medicine}},
school = {{Lund University}},
series = {{Lund University, Faculty of Medicine Doctoral Dissertation Series}},
title = {{Interactions between the kallikrein-kinin system, the complement system and extracellular vesicles in vascular inflammation}},
url = {{https://lup.lub.lu.se/search/files/209906711/Ingrid_Lopatko_Fagerstr_m_Thesis_upload.pdf}},
year = {{2025}},
}