血小板减少导致的出血长期困扰临床，加速巨核细胞增殖与分化是促血小板生成的关键环节。TPO/c-Mpl通路被认为是调控血小板生成的经典途径，但其激动剂促巨核细胞分化作用不明显且疗效欠佳。课题组前期从临床止血中药地榆中发现三甲基逆没食子酸（TMEA）能显著促进巨核细胞增殖与分化，提高血小板产量；但对TPO受体（c-Mpl）无明显作用，却可上调c-kit表达，促进Akt磷酸化，增强GATA-1转录；提示：TMEA通过c-kit/PI3K/Akt通路而非TPO/c-Mpl途径促巨核细胞分化。为此，本项目拟采用HEL c-Mpl-/-巨核细胞及c-Mpl-/-基因敲除小鼠为模型，应用流式细胞术、分子生物及药理学方法研究地榆单体TMEA促巨核细胞分化的体内、外活性及治疗作用，探讨对巨核细胞的形态、功能及信号通路的调控机制。从新的视角阐释地榆止血功效的科学内涵，也为发现新型促血小板生成药物提供新的思路。

Bleeding caused by thrombocytopenia is a great challenge in clinic for a long time, in which the proliferation and differentiation of megakaryocytes plays a key role in the treatment of thrombocytopenia. Recently, it is reported that the TPO/c-Mpl classic pathway improves the proliferation of megakaryocytes, but have little effect on the differentiation of megakaryocytes and thrombocytopenia. Therefore, the TPO/c-Mpl classic pathway can not explain the regulatory mechanism so far. Our previous studies showed that the TMEA from Sanguisorba officinalis L., an important hemostatic traditional Chinese medicine (TCM), have the significant stimulative effect on the proliferation and differentiation of megakaryocytes. Moreover, TMEA can up-regulate the mRNA expression of c-kit, phosphorylation-level of Akt protein and transcription of GATA-1, rather than the influence of c-Mpl expression. Therefore, we hypothesis that trimethyl ellagic acid promotes the differentiation of megakaryocytes via c-kit/PI3K/Akt pathway instead of TPO/c-Mpl classic pathway. The purpose of this study is aim to investigate the effect of TMEA on the differentiation of megakaryocytes and the associated mechanisms, using the models of c-Mpl-/- (c-Mpl knocked out) HEL cells and c-Mpl-/- mice by multiple techniques including gene knockout, flow cytometry, cellular and molecular biologic methods. This study may help to illuminate the modern medical support for TCM hemostasis theory of Sanguisorba officinalis L. from a new viewpoint, also provide new strategy for the treatment of thrombocytopenia and development of novel original thrombopoietic agents through c-kit/PI3K/Akt pathway.