Abstract Number: LPB0087
Meeting: ISTH 2021 Congress
Background: In sepsis, platelets become activated and shed increased amount of microvesicles containing several bioactive proteins and microRNAs (miRNAs). The latter molecules can be taken up by distinct recipient cells of circulation, thus utilize potent effects to regulate cellular function in different diseases.
Aims: We investigated the release of miR-223 from activated human platelets and transfer via microparticles (PMPs) into endothelial cells to downregulate enhanced intercellular adhesion molecule-1 (ICAM-1) expression among septic conditions in vitro.
Methods: To observe whether platelet-derived miR-223 carried by PMPs could enter endothelial cells, human coronary artery endothelial cells (HCAECs) were co-cultured with isolated PMPs from sepsis and normal plasma. Flow cytometry was used for quantification of CD41a/Annexin-V positive PMPs, and immunofluorescence microscopy was performed to detect the internalization of PMPs into endothelial cells. Expression of miR-223-3p and its direct target ICAM1 were quantified by RT-qPCR and ELISA in HCAECs after treatment with TNF-a with or without PMPs.
Results: Leukocyte-depleted platelets (LDPs) isolated from sepsis patients showed decreased expression of intracellular miR-223, while their plasma samples as well as PMPs contained elevated miRNA level compared to healthy samples. Similarly, thrombin-receptor activated LDPs showed reduced miR-223 intracellularly with high level in the supernatants and PMP isolates in vitro. In addition, we found higher PMP count in sepsis plasma compared to controls and increased PMP uptake by HCAECs. TNF-a stimulated HCAECs showed decreased miR-223 with elevated ICAM1, while PMPs caused higher miRNA level that attenuated ICAM1 expression at mRNA and protein levels. Importantly, miR-223 was not transcribed in response to PMPs as pre-miR-223 was not altered by PMPs, while mature miR-223 was still induced in PMP-treated vs. untreated HCAECs after transfection with Dicer1 siRNA.
Conclusions: miR-223 delivery by PMPs from septic platelets can modulate ICAM1 expression in endothelial cells that may be a protective role against sepsis-induced vascular inflammation.
To cite this abstract in AMA style:Szilágyi B, Fejes Z, Rusznyák Á, Fenyvesi F, Pócsi M, Halmi S, Griger Z, Kunapuli SP, Kappelmayer J, BN. Activated Platelets Transfer miR-223 into Endothelial Cells via Microparticles to Downregulate ICAM-1 Expression among Septic Conditions [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/activated-platelets-transfer-mir-223-into-endothelial-cells-via-microparticles-to-downregulate-icam-1-expression-among-septic-conditions/. Accessed May 16, 2022.
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