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Updated: Jul 18, 2025
Isolation of Mouse Megakaryocyte Progenitors
Published on: May 20, 2021
Megakaryocyte NLRP3 hyperactivation induces mild anemia and potentiates inflammatory response in mice
Joshua H Bourne1,2, Joana Campos1, Sophie J Hopkin1
1Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.
Background:
The NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome has been described in both immune cells and platelets, but its role in the megakaryocyte (MK) lineage remains elusive.
Objective:
The aim of this study was to explore the role of NLRP3 inflammasome in megakaryocytes and platelets.
Methods:
We generated Nlrp3 A350V/+/Gp1ba-CreKI/+ mice carrying a mutation genetically similar to the one observed in human Muckle-Wells syndrome, which leads to hyperactivity of NLRP3 specifically in MK and platelets.
Results:
Platelets from the mutant mice expressed elevated levels of both precursor and active form of caspase-1, suggesting hyperactivity of NLRP3 inflammasome. Nlrp3 A350V/+/Gp1ba-CreKI/+ mice developed normally and had normal platelet counts. Expression of major platelet receptors, platelet aggregation, platelet deposition on collagen under shear, and deep vein thrombosis were unchanged. Nlrp3 A350V/+/Gp1ba-CreKI/+ mice had mild anemia, reduced Ter119+ cells in the bone marrow, and splenomegaly. A mild increase in MK TGF-β1 might be involved in the anemic phenotype. Intraperitoneal injection of zymosan in Nlrp3 A350V/+/Gp1ba-CreKI/+ mice induced increased neutrophil egression and elevated levels of a set of proinflammatory cytokines, alongside IL-10 and G-CSF, in the peritoneal fluid as compared with control animals.
Conclusion:
MK/platelet NLRP3 inflammasome promotes the acute inflammatory response and its hyperactivation in mice leads to mild anemia and increased extramedullary erythropoiesis.
Insights
Hyperactivation of the NLRP3 inflammasome in megakaryocytes and platelets promotes acute inflammation. This hyperactivation in mice causes mild anemia and increased extramedullary erythropoiesis, impacting the immune response.
Area of Science:
- Immunology
- Hematology
Background:
- The NLRP3 inflammasome is present in immune cells and platelets, but its function in megakaryocytes (MKs) is not well understood.
- Understanding NLRP3 inflammasome activity in the MK lineage is crucial for comprehending its role in platelet biology and hematopoiesis.
Purpose of the Study:
- To investigate the role of the NLRP3 inflammasome specifically within the megakaryocyte and platelet lineage.
- To determine the consequences of NLRP3 inflammasome hyperactivation in MKs and platelets.
Main Methods:
- Generated Nlrp3 A350V/+/Gp1ba-CreKI/+ mice with NLRP3 hyperactivation specifically in MKs and platelets, mimicking human Muckle-Wells syndrome.
- Assessed platelet function, hematological parameters, bone marrow cellularity, spleen size, and inflammatory responses to zymosan challenge.
Main Results:
- Mutant mice showed NLRP3 inflammasome hyperactivity in platelets, indicated by elevated caspase-1 levels.
- Despite normal platelet counts and function, mutant mice exhibited mild anemia, reduced bone marrow erythroid precursors, and splenomegaly.
- Zymosan injection in mutant mice led to increased neutrophil egress and elevated pro-inflammatory cytokines in peritoneal fluid.
Conclusions:
- The NLRP3 inflammasome in megakaryocytes and platelets plays a role in promoting acute inflammatory responses.
- Hyperactivation of this inflammasome results in mild anemia and enhanced extramedullary erythropoiesis in mice.
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