Thrombopoietin maintains cell numbers of hematopoietic stem and progenitor cells with megakaryopoietic potential.

Thrombopoietin (THPO) has long been known to influence megakaryopoiesis and hematopoietic stem and progenitor cells (HSPCs), though the exact mechanisms through which it acts are unknown. Here we show that MPL expression correlates with megakaryopoietic potential of HSPCs and identify a population of quiescent progenitor cells that show limited dependence on THPO signalling. We show that THPO is primarily responsible for maintenance of hematopoietic cells with megakaryocytic (Mk) differentiation potential and their subsequent Mk differentiation and maturation.

Thrombopoietin Metabolically Primes Hematopoietic Stem Cells to Megakaryocyte-Lineage Differentiation.

During acute myelosuppression or thrombocytopenia, bone marrow (BM) hematopoietic cells respond rapidly to replenish peripheral blood platelets. While the cytokine thrombopoietin (Thpo) both regulates platelet production and maintains HSC potential, whether Thpo controls megakaryocyte (Mk)-lineage differentiation of HSCs is unclear. Here, we show that Thpo rapidly upregulates mitochondrial activity in HSCs, an activity accompanied by differentiation to an Mk lineage.