Identifying and enriching platelet-producing human stem cell-derived megakaryocytes using factor V uptake

Area of Science:

• Hematology
• Cell Biology
• Biotechnology

Background:

• Stem cell-derived platelets offer a promising alternative to donor platelets for transfusion.
• Optimizing in vitro platelet generation requires a deeper understanding of megakaryocyte (MK) maturation and function.

Purpose of the Study:

• To identify and characterize distinct human megakaryocyte (MK) populations during in vitro maturation.
• To define a specific MK subpopulation primed for functional platelet release.

Main Methods:

• Utilized two human stem cell models of megakaryopoiesis.
• Employed flow cytometry to define MK populations based on granularity and CD42b expression.
• Investigated the uptake and release of coagulation factor V (FV) by MKs and platelet-like particles.

Main Results:

• Identified immature (LG) and mature (HG) MK pools, with HG MKs undergoing apoptosis and CD42b shedding.
• Defined an undamaged HG/CD42b+ MK subpopulation that releases functional FV+CD42b+ platelet-like particles.
• Demonstrated that inhibiting apoptosis enriches functional MKs, increasing platelet yield in vivo.

Conclusions:

• Characterized a novel transition between distinct MK populations, identifying a subset primed for platelet release.
• Highlighting the importance of selecting or protecting these specific MKs for efficient functional platelet generation.
• Suggests that technologies optimizing platelet-ready MKs are key for advancing stem cell-derived platelet therapies.