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Routine Screening Method for Microparticles in Platelet Transfusions
Published on: January 31, 2018
Suppression of NK cell function by platelet-derived microparticles: implications for transfusion-related
Huixin Chen1, Bicheng Hu2, Nian Si3
1Department of Transfusion Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Transfusion Medicine, Traditional Chinese and Western Medicine Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Abstract:
The immunomodulatory effects of platelet-derived microparticles (PMPs) on host innate immunity remain incompletely understood. In this study, we established a clinically relevant in vitro model using PMPs from stored platelets to investigate their effects on NK cell function. PMPs were isolated from platelets of 3 healthy donors, and co-cultured with PBMCs or primary NK cells from 18 healthy donors. Their effects on NK cell activation, cytotoxic function, and IFN-γ secretion were assessed by flow cytometry. qRT-PCR was performed to detect the mRNA expression of four key NK functional genes (IFNG, GZMB, PRF1 and FOXO1). High-throughput small RNA sequencing coupled with bioinformatic analysis was applied to screen PMP-derived miRNAs, and miR-223-3p was identified as a candidate functional mediator. We further conducted ex vivo validation of this effect using PBMCs from 12 sepsis patients. PMPs accumulating to estimated transfusion-relevant concentrations in stored platelets modulate NK cell activation, IFN-γ production, cytotoxic molecule expression and K562 cell killing in a concentration-dependent manner. Transcriptional detection results suggest that the downregulation of cytotoxic effector proteins induced by PMPs may be predominantly regulated by post-transcriptional pathways, which are possibly mediated by miR-223-3p. Our findings identify a potential pathway by which PMPs accumulating during platelet storage may contribute to transfusion-related immunomodulation, offering a preliminary mechanistic framework. Notably, the results of our ex vivo validation using samples from sepsis patients provide a foundation for the hypothesis that PMP-mediated NK cell modulation may contribute to immune dysregulation in clinical scenarios, such as sepsis, where platelet transfusions are common.
Insights
Platelet-derived microparticles (PMPs) from stored platelets can suppress natural killer (NK) cell function, impacting immune responses. This suggests PMPs may contribute to transfusion-related immunomodulation and immune dysregulation in sepsis.
Area of Science:
- Immunology
- Cell Biology
- Transfusion Medicine
Background:
- Platelet-derived microparticles (PMPs) are released from platelets and can influence immune cell function.
- The immunomodulatory effects of PMPs, particularly those from stored platelets, on innate immunity are not fully understood.
- NK cells are crucial components of the innate immune system, mediating anti-viral and anti-tumor responses.
Purpose of the Study:
- To investigate the effects of PMPs from stored platelets on natural killer (NK) cell function in vitro.
- To identify potential molecular mechanisms, including microRNAs (miRNAs), involved in PMP-mediated NK cell modulation.
- To validate findings in a clinical context using samples from sepsis patients.
Main Methods:
- PMPs were isolated from stored platelets and co-cultured with peripheral blood mononuclear cells (PBMCs) or primary NK cells.
- NK cell activation, cytotoxicity, and interferon-gamma (IFN-γ) secretion were assessed by flow cytometry.
- Gene expression (qRT-PCR) and small RNA sequencing were used to identify functional mediators, with miR-223-3p identified as a candidate.
Main Results:
- PMPs from stored platelets modulated NK cell activation, IFN-γ production, and cytotoxic molecule expression in a concentration-dependent manner.
- PMP treatment reduced NK cell-mediated killing of K562 target cells.
- Results suggest post-transcriptional regulation, potentially mediated by miR-223-3p, contributes to PMP-induced NK cell dysfunction.
- Ex vivo validation in sepsis patients supported PMP-mediated NK cell modulation in clinical settings.
Conclusions:
- PMPs accumulating in stored platelets can suppress NK cell function, contributing to transfusion-related immunomodulation.
- MiR-223-3p is identified as a potential mediator of PMP-induced NK cell modulation.
- PMP-mediated NK cell dysfunction may play a role in immune dysregulation observed in clinical conditions like sepsis, where platelet transfusions are common.
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