ITP患者巨核细胞中通过抑制JIP3表达调节c-Mpl在细胞膜表面的分布及其机制研究

巨核细胞成熟障碍是原发免疫性血小板减少症（ITP）发病机制之一。血小板生成素TPO及其受体c-Mpl在巨核细胞成熟中发挥重要作用。我们前期工作发现c-Mpl在ITP患者巨核细胞膜表面相对分布降低，JIP3可以调节c-Mpl在巨核细胞膜表面分布，并且ITP患者巨核细胞JIP3表达降低。据此，我们提出假说：ITP患者巨核细胞JIP3表达不足使其c-Mpl膜表面分布减少，这导致该细胞对TPO反应降低和成熟障碍。本研究拟运用可裂解生物素标记、流式细胞术、活细胞拍照及ITP小鼠等，在体内外研究ITP患者巨核细胞中c-Mpl的膜表面分布及其对TPO的反应能力，分析JIP3调节c-Mpl在巨核细胞中运输并分布到膜表面的方式，寻找巨核细胞中调控JIP3表达的分子机制，并验证挽救JIP3在ITP小鼠巨核细胞中的表达对其血小板减少的治疗作用。本研究有助于深入认识ITP的发病机制，并为ITP临床治疗提供新靶点。

One pathogenesis of primary immune thrombocytopenia (ITP) is megakaryocyte maturation deficiency. Thrombopoietin (TPO) and its receptor c-Mpl play an important role in megakaryocyte maturation. From previous work, we found that relative distribution of c-Mpl on the megakaryocyte membrane was reduced in ITP patient samples. C-Jun N-terminal kinase (JNK) interacting protein 3 (JIP3) regulated the distribution of c-Mpl on megakaryocyte membrane, and the expression of JIP3 in megakaryocytes from ITP patients was decreased. Therefore, we raise the hypothesis that insufficient JIP3 expression in megakaryocytes leads to the decreasing of c-Mpl cell membrane distribution, which results in the reduction of TPO response and deficiency of megakaryocytes maturation in ITP patient samples. In this study, cleavable biotin labeling, flow cytometry, live imaging, and ITP mice will be used. The c-Mpl cell membrane distribution and the ability to respond to TPO of ITP patient megakaryocytes will be addressed in vivo and in vitro. Furthermore, we will analyze how JIP3 regulates the trafficking of c-Mpl and investigate the underlying molecular mechanisms that control the expression of JIP3 in megakaryocytes. In the end, by rescuing JIP3 expression in ITP mouse megakaryocytes, we will study its therapeutic effect on the decreased platelet number. These findings will deepen our understanding of ITP pathogenesis and provide a novel potential target for the clinical treatment of ITP.