Abstract
Platelet deficiency, known as thrombocytopenia, can cause haemorrhage and is treated with
platelet transfusions. We developed a system for the production of platelet precursor cells,
megakaryocytes, from pluripotent stem cells. These cultures can be maintained for >100 days,
implying culture renewal by megakaryocyte progenitors (MKPs). However, it is unclear
whether the MKP state in vitro mirrors the state in vivo, and MKPs cannot be purified using
conventional surface markers. We performed single cell RNA sequencing throughout in vitro
differentiation and mapped each state to its equivalent in vivo. This enabled the identification
of 5 surface markers which reproducibly purify MKPs, allowing us an insight into their
transcriptional and epigenetic profiles. Finally, we performed culture optimisation, increasing
MKP production. Altogether, this study has mapped parallels between the MKP states in vivo
and in vitro and allowed the purification of MKPs, accelerating the progress of in vitro-derived
transfusion products towards the clinic.