Megakaryocytes regulate the quiescence of hematopoietic stem cells through PF4: 2013 ASH meeting highlights.

Hematopoietic stem cells (HSCs) can take one of the three different pathways: quiescence, self-renewal and differentiation. Mechanisms that control the tight balance to maintain lifelong hematopoietic homeostasis have been a major interest of research. Platelet factor-4 (PF4), a weak chemokine, is synthesized exclusively by megakaryocytes and sequestered in platelets. This meeting report highlights a novel study presented at 2013 ASH annual meeting. This study found that megakaryocyte, a progeny of HSC, was involved in maintaining quiescence of HSCs via PF4 in a feedback loop.