IFN-γ-STAT1-SOCS-1下调促血小板生成素受体c-MPL在重型再生障碍性贫血发病中的机制研究

重型再生障碍性贫血（SAA）患者促血小板生成素（TPO）水平持续升高，提示造血干祖细胞（HSPCs）表面c-MPL表达下降或缺失。TPO-MPL是维持成体HSPCs的关键通路，c-MPL缺失可导致骨髓衰竭的发生。已知JAK2在c-MPL转运和膜定位中发挥重要作用。我们前期研究发现，干扰素-γ（IFN-γ）上调细胞因子抑制蛋白-1（SOCS-1）后加速JAK2降解，过表达JAK2可增加高尔基复合体内和细胞表面的c-MPL表达，但对c-MPL总蛋白没有影响。因此，我们设想IFN-γ可能通过上调SOCS-1促进JAK2降解，从而抑制c-MPL从粗面内质网向高尔基复合体的转运。本课题拟在前期研究的基础上，通过CRISP-Cas9、点突变、GST Pull-Down等实验方法在细胞和分子水平探讨IFN-γ对c-MPL转运的影响及机制。本研究如获成功将有助于深化对SAA发病机制的认识。

The decreased expression of thrombopoietin (TPO) receptor c-Mpl on the surface of hematopoietic stem progenitor cells (HSPCs) is an important cause of SAA, but the mechanism is unclear. TPO is a key hematopoietic factor for maintaining adult stem/progenitor cells (HSPCs). TPO binding to its receptor c-MPL triggers activation and phosphorylation Janus kinase 2 (JAK2) and mediates receptor endocytosis. The proinflammatory cytokine interferon-γ (IFN-γ) induces the expression of cytokine suppressor protein-1 (SOCS-1) with enhanced degradation of JAK2. JAK2 is required for Golgi processing and cell surface expression of c-MPL. We hypothesized that IFN-γ might promote JAK2 degradation by up-regulating SOCS-1, thereby inhibiting the transport of c-MPL from ER to the Golgi complex, which reduces the amount of c-MPL on the cell membrane surface and eventually leading to persistent high level of TPO. Based on previous research, this project intends to explore the effects of IFN-γ on c-MPL transport through CRISP-Cas9, point mutation, GST Pull-Down, and flow cytometry (FACS). The success of this study will improve our understanding of the pathogenesis of SAA and provide new sights for the development of a new generation of TPO receptor agonists.