Hb E/β-地贫的蛋白质量控制系统的研究

halassemia is a serious hereditary blood disease that threatens human's health, with regional pathogenetic characters. Southeast Asia is a highly prevalent area worldwide, featured with Hb E/β-thalassemia which is only emerged in Yunan of China. The direct cause of β-thalassemia is the accumulation of exceed free α-globin precipitates. This project focus on Hb E/β-thalassemia. Firstly, erythroid cell models whose genetypes are βN/βN、βE/βE、βE/β0、βE/β+ , will be built by collecting the human hematopoietic stem cell. In order to make clear when the accumulation of abnormal protein happened, the changes in the content of insoluble α-globin and SQSTM1/P62 are detected during the process of prorubricyte to mature erythrocyte; Then, which pathway free α-globin hydrolyzed in is planned to determined by Immunoprecipitation-Western blot analysis, detecting the expression of LC3Ⅱwhich is a key marker of autophagy and the level of insoluble α-globin after treatment with autophagy and proteasome inhibitors; finally, whether activating protein quality-control(PQC) is effectual in detoxify free α-globin will be measured by pretreatment with autophagy and proteasome inducers. In this project, β-thalassemia is defined as a protein-aggregation disorder, which indicates a novel view for thalassemia treatment.

地中海贫血是严重威胁人类健康的遗传性血液病，存在地区性发病特点，东南亚为重流行 区，以Hb E/β-地贫为主，此类型地贫在我国仅见于云南。过剩的游离α-肽链沉积是其发病的直接原因。本项目以Hb E/β-地贫为研究对象，采集人骨髓造血干细胞，建立基因型为βN/βN、βE/βE、βE/β0、βE/β+的红系细胞模型，在红细胞发育过程中，实时检测不溶性α-珠蛋白肽链沉淀物及SQSTM1/P62含量变化，明确异常蛋白沉积发生的时期；利用免疫沉淀-western blot分析、自噬-溶酶体通路标记分子LC3Ⅱ的检测，以及蛋白酶体抑制剂和自噬抑制剂预处理模型细胞后不溶性α-珠蛋白肽链含量的变化，阐明α-珠蛋白肽链的降解途径；通过泛素化-蛋白酶体通路激动剂和自噬-溶酶体诱导剂探索激活蛋白质量控制系统干预Hb E/β-地贫治疗的可行性。本项目将地贫定义为异常蛋白质沉积类疾病，为其治疗策略的探索指出新方向。

HbE/β-地中海贫血是一类β-珠蛋白生成障碍性贫血,多见于我国的西南。过剩的游离α-肽链沉积是其发病的直接原因，但其中的相关机制目前还不清楚。本课题建立了基于CD34+造血干细胞和外周血单个核细胞的两种HbE/β-地中海贫血细胞模型，在早幼红细胞发育至成熟红细胞过程中，存在不溶性α-珠蛋白肽链沉积。在HbE/β-地中海贫血中，泛素化-蛋白酶体通路和自噬通路与不溶性α-珠蛋白肽链沉积相关。使用雷帕霉素激活自噬通路，可以减轻Hb E/β-地贫患者成红血细胞中游离α-珠蛋白的积累，并可以改善Hb E/β-地贫小鼠模型的病状。这些研究结果：HbE/β-地中海贫血可能是一种异常蛋白质沉积类疾病；激活细胞的自噬途径可作为一种减轻β-地中海贫血的药物调节通路。