Profiling of COX-dependent Eicosanoids Produced by Blood Cells and the Vasculature

M. Crescente¹, P.C. Armstrong¹, N.S. Kirkby², M.L. Edin³, M.V. Chan¹, F.B. Lih³, J. Jiao⁴, T. Maffucci¹, H.E. Allan¹, C.A. Mein¹, C. Gaston-Massuet⁵, G.S. Cottrell⁶, J.A. Mitchell², D.C. Zeldin³, H.H. Herschman⁴, T.D. Warner¹

¹Queen Mary University London, Blizard Institute, London, United Kingdom, ²Imperial College London, London, United Kingdom, ³National Institute of Environmental Health Sciences, Durham, United States, ⁴UCLA, Los Angeles, United Kingdom, ⁵Queen Mary University London, William Harvey Institute, London, United Kingdom, ⁶University of Reading, Reading, United Kingdom

Abstract Number: PB1704

Meeting: ISTH 2020 Congress

Theme: Platelets and Megakaryocytes » Platelet Function and Interactions

Background: Cyclooxygenase (COX) metabolism of arachidonic acid (AA) leads to the production of eicosanoids such as thromboxane (Tx)A₂, prostaglandin (PG)I₂and PGE₂, important for thrombosis, inflammation and cancer. However, platelets, endothelial cells and leukocytes synthesize other metabolites not comprehensively profiled.

Aims: Here, we used platelet-COX-1 knockout (KO), global-COX-1 KO and aspirin-treated control mice to determine by mass spectrometry the eicosanoid profile associated with the activity of COX-1 in platelets and of COX-1 and COX-2 in other blood cells and vasculature.

Methods: In vitro stimulation of whole blood with A23187 (50 µM) or in vivo injection of AA (2.8 mg/Kg) were used to elicit eicosanoid release. The levels of metabolites were determined by mass-spectrometry.

Results: Hierarchical analysis identified 3 different clusters of AA-derived eicosanoids produced in vitro: 1) TxA_2,PGF_2α, 11- hydroxyeicosatraenoic acid (HETE) and 15-HETE, that were absent in platelet-COX-1 and global-COX-1 KO mice; 2) PGD₂ and PGE₂, that were absent in global-COX-1 KO mice and partially reduced in platelet-COX-1 KO mice; 3) 5-HETE, 12-HETE and leukotriene B₄ that were unchanged. Eicosanoids produced in vivo clustered differently in platelet-COX-1 ko mice than in global-COX-1 KO and aspirin-treated control mice. All demonstrated absence of TxA₂but, unlike global-COX-1 KO and aspirin (10 mg/Kg)-treated control mice, platelet COX-1 KO mice still produced PGI₂, PGE₂, PGF_2α, 11-HETE and 15-HETE. From these data, Ingenuity Pathway Analysis (IPA) predicted enhanced cardiovascular protection for platelet-COX-1 KO mice, but increased thrombosis in global COX-1 KO and aspirin-treated mice. Lessened inflammation was predicted in global COX-1 KO and aspirin-treated mice, while cancer was predicted as decreased in platelet COX-1 KO mice, global COX-1 KO and aspirin-treated mice.

Conclusions: The activity of COX-1 in platelets and of COX-1 and COX-2 in other blood cells and the vasculature associate to distinct eicosanoid profiles underpinning important and different roles in cardiovascular, inflammation and cancer protection.

To cite this abstract in AMA style:

Crescente M, Armstrong PC, Kirkby NS, Edin ML, Chan MV, Lih FB, Jiao J, Maffucci T, Allan HE, Mein CA, Gaston-Massuet C, Cottrell GS, Mitchell JA, Zeldin DC, Herschman HH, Warner TD. Profiling of COX-dependent Eicosanoids Produced by Blood Cells and the Vasculature [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/profiling-of-cox-dependent-eicosanoids-produced-by-blood-cells-and-the-vasculature/. Accessed October 1, 2023.

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