Comparison of Mature Megakaryocytes Differentiated by TPO or Small Molecule TPO Mimetics

TPO mimetics have been shown to activate TPO receptor, the downstream JAK-STAT pathway, and induce differentiation of hematopoietic stem cells into megakaryocytes. However, the action of these TPO mimetics is initiated by binding to the transmembrane domain of the TPO receptor, which is distinct from the binding site of the native ligand, TPO. To determine whether TPO mimetics can differentiate hematopoietic stem cells into the same megakaryocytes as native TPO does, we performed a microarray experiment to compare the globe gene expression in purified CD61+ cells derived from TPO or TPO mimetic treated CD34+ bone marrow cells. Keywords: Drug Treatment Purified human bone marrow hematopoietic CD34+ cells were cultured with rhSCF at 100 ng/mL, and either 100 ng/mL rhTPO, 3 µM eltrombopag, or 1 µM LGD-4665 for 10 days. The mature megakaryocytes were enriched using anti-CD61 Miltenyi beads, and RNA was purified from these CD61+ cells. Each RNA sample was used to create a probe which was hybridized to a single microarray. In sum, there were four biological replicates for TPO treatment group, and three replicates for LGD-4665 and eltrombopag (each group had a missing sample due to low quantity or quality of RNA), with no technical replicates.