Abstract
Background Platelets are an abundant source of micro-ribonucleic acids (miRNAs) that may play
a role in the regulation of platelet function. Some miRNAs, such as miR-126-3p, have
been noted as potential biomarkers of platelet reactivity and the recurrence of cardiovascular
events. However, the biological relevance of these associations remains uncertain,
and the functional validation of candidate miRNAs on human-derived cells is lacking.
Objective This article functionally validates miR-126-3p as a regulator of platelet reactivity
in platelet-like structures (PLS) derived from human haematopoietic stem cells.
Materials and Methods CD34+-derived megakaryocytes were transfected with miR-126-3p and differentiated in PLS.
PLS reactivity was assessed using perfusion in a fibrinogen-coated flow chamber. miR-126-3p's
selected gene targets were validated using quantitative polymerase chain reaction,
protein quantification and a reporter gene assay.
Results CD34+-derived megakaryocytes transfected with miR-126-3p generated PLS exhibiting 156%
more reactivity than the control. These functional data were in line with those obtained
analysing CD62P expression. Moreover, miR-126-3p transfection was associated with
the down-regulation of a disintegrin and metalloproteinase-9 (ADAM9) messenger RNA
(mRNA), a validated target of miR-126-3p, and of Plexin B2 (PLXNB2) mRNA and protein,
an actin dynamics regulator. Silencing PLXNB2 led to similar functional results to
miR-126-3p transfection. Finally, using a reporter gene assay, we validated PLXNB2
as a direct target of miR-126-3p.
Conclusion We functionally validated miR-126-3p as a regulator of platelet reactivity in PLS
derived from human haematopoietic stem cells. Moreover, PLXNB2 was validated as a
new gene target of miR-126-3p in human cells, suggesting that miR-126-3p mediates
its effect on platelets, at least in part, through actin dynamics regulation.
Keywords
microRNA - platelet - platelet function tests - flow-based assay - PLXNB2
