炎症过程中UBQLN2调控P-选凝素细胞内转运分子机制研究

Cell adhesion molecule P-selectin plays an important role in inflammation and tumor formation. The function of P-selectin is strictly regulated by its trafficking within cells. However, the molecular mechanism of P-selectin trafficking is unknown. Our previous findings indicate that UBQLN2 (Ubiquilin-2), an ubiquitin-like protein, is critically involved in the trafficking of P-selectin between cytoplasm and membrane. Our preliminary data show that Ubiquilin-2 could directly bind to P-selectin, and up-regulate the expression of P-selectin on cell mambrane. Our further study show that blocking the binding of Ubiquilin-2 to P-selectin could dramatically inhibit the important function of P-selectin in vivo. In this project, we will try to further explore the molecular mechanism of Ubiquilin-2 regulated cellular trafficking of P-selectin. Especially, we will set up high throughput and high content screening system to search for active small chemicals which could inhibit the interaction of Ubiquilin-2 and P-selectin, and search for new critical molecules involved in this regulating pathway by performing genome-wide siRNA screening. With this new chemical probes and molecular clues, we will try to further our investigation in primary cells and animal models. Meanwhile, identification of small chemical inhibitor will not only be beneficial for our basic research but also may throw lights to new therapy tool for anti-inflammation. Overall, our studies will elucidate the novel interaction and regulation mechanism of Ubiquilin-2 and P-selectin in inflammation, which will be valuable for discovering new therapy for inflammatory diseases.

细胞粘附分子P-选凝素在炎症性疾病以及肿瘤的发生发展过程中发挥关键作用，其活性的发挥受细胞内转运调控的精细调节，但对于P-选凝素在细胞内的转运调控机制的揭示仍缺乏研究。我们的前期工作提示类泛素蛋白UBQLN2很可能是调控P-选凝素细胞内转运的重要调控分子。我们已发现UBQLN2可直接结合P-选凝素且可促进其在细胞膜上的表达, 并对P-选凝素生物学功能发挥具有重要影响。进一步，我们将用常规分子、细胞生物学手段，深入研究UBQLN2调控P-选凝素细胞内转运分子机制。特别是我们还将建立高通量高内涵筛选体系，筛选调控UBQLN2与P-选凝素相互结合的小分子化合物和活性基因，利用小分子抑制剂等深入揭示UBQLN2对P-选凝素的转运调控机理，及研发相关抗炎药物。我们的工作首次把Ubiquilins蛋白功能引入炎症系统，有望在阐明新的细胞内分子转运调控机理的同时，为炎症性疾病的治疗提供有价值的理论依据。

细胞粘附分子P-选凝素在炎症性疾病以及肿瘤的发生发展过程中发挥关键作用，其活性的发挥受细胞内转运调控的精细调节，但对于P-选凝素在细胞内的转运调控机制的揭示仍缺乏研究。 我们的前期工作提示类泛素蛋白UBQLN2很可能是调控P-选凝素细胞内转运的重要调控分子。我们已发现UBQLN2可直接结合P-选凝素且可促进其在细胞膜上的表达, 并对P-选凝素生物学功能发挥具有重要影响。在研究UBQLN2与P-选凝素相互结合的小分子化合物和活性基因，利用小分子抑制剂等深入揭示UBQLN2对P-选凝素的转运调控机理，及研发相关抗炎药物的过程中，我们建立和优化了各种生化水平以及细胞水平的高通量、高内涵筛选系统，为了验证我们系统的优越性，我们成功地将这些筛选系统应用于一个更趋成熟的研究体系即阻断肝癌细胞中高表达的关键蛋白Survivin与其结合蛋白Borealin的相互结合来抑制肝癌细胞的增殖。在研究中，我们筛选获得了几种可明显抑制活细胞内Survivin与Borealin相互结合的活性小分子，确认了小分子的作用靶点，同时发现活性小分子可以特异地抑制Survivin高表达的肝癌细胞增殖。这些结果显示我们建立的筛选体系的稳定性和优越性。我们的筛选技术可为类似的研究提供稳定可靠的研究工具。我们现有的研究成果为相关肝癌疾病的治疗提供了有价值的新线索。