TPO and Thrombocytopenia: Inagaki et al. (2004) reported that a novel small molecule (JTZ-132) induces the growth and differentiation of megakaryocytic progenitor cells and improves thrombocytopenia in myelosuppressed mice via tyrosine phosphorylation of c-Mpl, JAK2, and STAT5. A study by Kirito et al. (2002) revealed that STAT3 plays an important role in megakaryopoiesis through the expansion of megakaryocyte progenitor cells. Similarly, Grozovsky et al. (2015) demonstrated that Ashwell-Morell receptor regulates hepatic TPO production via JAK2-STAT3 signaling.