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Updated: Mar 13, 2026
Purification of Platelets from Mouse Blood
Published on: May 7, 2019
Deletion of mPGES-1 affects platelet functions in mice
Joan Raouf1, Fariborz Mobarrez1, Karin Larsson1
1Unit of Rheumatology, Department of Medicine, Solna, Karolinska Institutet, and Unit of Rheumatology, Karolinska University Hospital, SE-171 76 Stockholm, Sweden.
Abstract:
Microsomal prostaglandin E2 synthase-1 (mPGES-1) constitutes an essential player in inflammation and is involved in the pathogenesis of rheumatoid arthritis. Platelets participate in the regulation of inflammatory processes by the release of proinflammatory mediators and platelet-derived microparticles (PMPs). However, the role of the inducible mPGES-1/PGE2 pathway in platelet functions has not been investigated. In the present study we report a significant impact of mPGES-1 on platelet functions during inflammation. Wild-type (WT) and mPGES-1-/- knockout (KO) mice were stimulated with lipopolysaccharide (LPS) for 24 h. Platelet counts and activation were assessed by flow cytometry analysing CD62P-CD154 expression, PMP numbers, platelet-leukocyte aggregates and platelet aggregation. The accumulation of platelets and fibrinogen in the liver was analysed by immunofluorescent staining. In native platelets from WT and mPGES-1 KO mice, there were no differences among the investigated functions. After LPS treatment, the number of platelets was significantly decreased in WT, but not in KO mice. Platelet activation, platelet-leukocyte aggregates and PMP numbers were all significantly lower in KO mice compared with WT mice after LPS treatment. In addition, KO mice displayed a significant reduction in platelet aggregation ex vivo In the liver of LPS-stimulated WT and KO mice, there were no differences in platelet accumulation, although the percentage of total vessel area in the KO liver was significantly lower compared with the WT one. Our results demonstrate that systemic inhibition of mPGES-1 prevents platelet activation, which should have important implications with regard to the cardiovascular safety of mPGES-1 inhibitors.
Insights
Microsomal prostaglandin E2 synthase-1 (mPGES-1) inhibition prevents platelet activation during inflammation. Mice lacking mPGES-1 showed reduced platelet aggregation and fewer inflammatory platelet markers after LPS stimulation.
Area of Science:
- Biomedical research
- Inflammation and immunology
- Cardiovascular research
Background:
- Microsomal prostaglandin E2 synthase-1 (mPGES-1) is crucial in inflammation and rheumatoid arthritis pathogenesis.
- Platelets regulate inflammation via mediators and microparticles, but their mPGES-1/PGE2 pathway role is unknown.
Purpose of the Study:
- To investigate the role of the mPGES-1/PGE2 pathway in platelet function during inflammation.
- To assess the impact of mPGES-1 deficiency on platelet activation and aggregation.
Main Methods:
- Comparison of wild-type (WT) and mPGES-1 knockout (KO) mice stimulated with lipopolysaccharide (LPS).
- Assessment of platelet counts, activation (CD62P-CD154), microparticle numbers, platelet-leukocyte aggregates, and aggregation via flow cytometry and ex vivo assays.
- Immunofluorescent staining for platelet and fibrinogen accumulation in the liver.
Main Results:
- LPS treatment decreased platelet counts in WT but not KO mice.
- KO mice exhibited significantly lower platelet activation, platelet-leukocyte aggregates, and PMP numbers post-LPS.
- KO mice showed reduced ex vivo platelet aggregation.
- No difference in liver platelet accumulation between WT and KO mice, but reduced vessel area in KO liver.
Conclusions:
- Systemic mPGES-1 inhibition effectively prevents platelet activation during inflammation.
- These findings have significant implications for the cardiovascular safety of mPGES-1 inhibitors.
