Throughout the COVID-19 pandemic, the civilian medical sector encountered a critical blood shortage, particularly in platelet donations. Platelets, the smallest blood cells in the human body, are responsible for clotting blood, and play an important role in maintaining hemostasis. For major traumatic events and penetrating injuries, platelet transfusion units are often needed to assist in blood clot formation. However, the short shelf life of platelet transfusion units and critical shortage in the civilian sector prompted a desperate need to research and improve units to allow for a longer shelf life. However, platelet research requires donor platelets, resulting in even further stress on the already critical shortage. In this poster, a human megakaryoblast leukemia cell line, MEG-01, was developed and matured into platelet-like particles. It is the hope that these platelet-like particles can survive and perform similarly in functional assays to that of human platelets. Confirmation of their similar activation and behavioral patterns would allow for the study of platelets and platelet units without the need for human donors.

Before performing functional assays, MEG-01 cells were treated with either recombinant human thrombopoietin (TPO) or phorbol myristate acetate (PMA) for 72 hours. Induced PLPs were size-selected to obtain TPO-induced platelet-like particles (TPO-PLP) or PMA-induced PLP (PMA-PLP). TPO-PLP, PMA-PLP, and human donor platelets underwent the following functional assays: platelet aggregometry, calcium mobilization assay, and Oroboros mitochondrial respiration study. PLP derived from TPO treatment showed higher and more viable yields than those from PMA. TPO-PLP also showed a pattern of Ca2+ mobilization similar to that of healthy human platelets. In both, fluorescent levels increased in response to treatment with five different receptor agonists while the response in PMA-PLP was consistently lower. In platelet aggregometry, TPO-PLP aggregation was robust in response to the activator, collagen. However, PMA-derived PLPs did not show a response to collagen. In an early Oroboros study, TPO-PLPs appear to have viable mitochondria that behave similarly to freshly harvested healthy platelets.

Moving forward, more experiments are necessary to confirm these early findings. In summary, TPO-induced PLP are healthier and perform better on platelet functional assays than PLP derived from PMA treatment. Our data from multiple functional assays support our development of our MEG-01 PLP-generating system for modeling human platelets.