https://orcid.org/0000-0003-4240-5498
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Abstract
Platelets are anucleate cells that have a role in several innate immune functions, including the secretion of proteins with antimicrobial activity. Several studies have demonstrated the ability of platelets to secrete thrombin-induced platelet microbicidal proteins and antimicrobial peptides, like hBD-1. However, the expression and secretion of defensins of the alpha family by platelets have not been fully elucidated. The aim of this study was to characterize the expression of defensin alpha 1 (DEFA1) in human platelets and megakaryocytes. Our data indicate that DEFA1 mRNA and protein are present in peripheral blood platelets and in the megakaryoblastic leukemia cell line (MEG-01). DEFA1 co-localize with α-granules of platelets and MEG-01 cells, and was also detected in cytoplasm of MEG-01 cells. The assay of our in vitro model of platelet-like particles (PLPs) revealed that MEG-01 cells could transfer DEFA1 mRNA to their differentiated PLPs. Furthermore, platelets secreted DEFA1 into the culture medium when activated with thrombin, adenosine diphosphate, and lipopolysaccharide; meanwhile, MEG-01 cells secreted DEFA1 when activated with thrombopoietin. Platelet’s secreted DEFA1 can rebind to platelet’s surface and have antibacterial activity against the gram-negative bacteria Escherichia coli. In summary, our data indicate that both, human platelets and megakaryocytes, can express and secrete DEFA1. These results suggest a new role of platelets and megakaryocytes in the innate immune response.
Acknowledgements
The authors acknowledge laboratory students at the Department of Experimental Biomedicine in the Faculty of Medicine and Surgery at Benito Juárez University in Oaxaca for their help.
In addition, the authors extend their appreciation to the National Laboratory of Cytometry (LabNalCit) for their support in completing this project.
Declaration of Interest statement
The authors have no conflicts of interest to report.
The National Council for Science and Technology (CONACyT) financed this work through the open call for Basic Science from Young Researchers 2013-2014. Project number: 223607.
Statement of Contribution
All persons who meet authorship criteria are listed as authors, and all authors certify that they have participated sufficiently in the work to take public responsibility for the content, including participation in at least one of the categories below.
Conception or design of the work: X.R. Valle; J. Serafin; S.R. Aguilar.
Data collection: X.R. Valle; A. Ramírez; A.S. Aquino; F. Sánchez.
Data analysis and interpretation: X.R. Valle; M.D.L.A. Romero; H. Torres.
Drafting the article: X.R. Valle; J. Bustos.
Critical revision of the article: J. Serafin; S.R. Aguilar.
Final approval of the version to be published: X.R. Valle; A. Ramírez; A.S. Aquino; F. Sánchez; H. Torres; J. Bustos; M.D.L.A. Romero; J. Serafin; and S.R. Aguilar.
Furthermore, each author certifies that this material or similar material has not been and will not be submitted to or published in any other publication before its appearance in Platelets.
Supplementary Material
Supplemental data for this article can be accessed here.