Complement and platelets : prothrombotic cell activation requires membrane attack complex-induced release of danger signals

© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved..

Complement activation in the diseases paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS) results in cytolysis and fatal thrombotic events, which are largely refractory to anticoagulation and/or antiplatelet therapy. Anticomplement therapy, however, efficiently prevents thrombotic events in PNH and aHUS, but the underlying mechanisms remain unresolved. We show that complement-mediated hemolysis in whole blood induces platelet activation similarly to activation by adenosine 5'-diphosphate (ADP). Blockage of C3 or C5 abolished platelet activation. We found that human platelets failed to respond functionally to the anaphylatoxins C3a and C5a. Instead, complement activation did lead to prothrombotic cell activation in the whole blood when membrane attack complex (MAC)-mediated cytolysis occurred. Consequently, we demonstrate that ADP receptor antagonists efficiently inhibited platelet activation, although full complement activation, which causes hemolysis, occurred. By using an established model of mismatched erythrocyte transfusions in rats, we crossvalidated these findings in vivo using the complement inhibitor OmCI and cobra venom factor. Consumptive complement activation in this animal model only led to a thrombotic phenotype when MAC-mediated cytolysis occurred. In conclusion, complement activation only induces substantial prothrombotic cell activation if terminal pathway activation culminates in MAC-mediated release of intracellular ADP. These results explain why anticomplement therapy efficiently prevents thromboembolisms without interfering negatively with hemostasis.

Errataetall:

CommentIn: Blood Adv. 2023 Oct 24;7(20):6364-6366. - PMID 37874560

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:7

Enthalten in:

Blood advances - 7(2023), 20 vom: 24. Okt., Seite 6367-6380

Sprache:

Englisch

Beteiligte Personen:

Mannes, Marco [VerfasserIn]
Pechtl, Veronika [VerfasserIn]
Hafner, Susanne [VerfasserIn]
Dopler, Arthur [VerfasserIn]
Eriksson, Oskar [VerfasserIn]
Manivel, Vivek Anand [VerfasserIn]
Wohlgemuth, Lisa [VerfasserIn]
Messerer, David Alexander Christian [VerfasserIn]
Schrezenmeier, Hubert [VerfasserIn]
Ekdahl, Kristina N [VerfasserIn]
Nilsson, Bo [VerfasserIn]
Jacobsen, Eva-Maria [VerfasserIn]
Hoenig, Manfred [VerfasserIn]
Huber-Lang, Markus [VerfasserIn]
Braun, Christian K [VerfasserIn]
Schmidt, Christoph Q [VerfasserIn]

Links:

Volltext

Themen:

Complement Membrane Attack Complex
Journal Article
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 13.11.2023

Date Revised 10.01.2024

published: Print

CommentIn: Blood Adv. 2023 Oct 24;7(20):6364-6366. - PMID 37874560

Citation Status MEDLINE

doi:

10.1182/bloodadvances.2023010817

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM359298745