小分子化合物Niclosamide调控JAK/STAT信号通路影响衰老造血干细胞功能及其机制研究

Owing to the bias of myeloid development and defects in hematopoietic reconstitution function, hematopoietic stem cell (HSC) aging is a hot topic in stem cell research. In present study, the transcriptome maps of lineage-Scal+c-Kit+ HSC from bone marrow of young (8-week-old) and old (18-month-old) mice were drawn by single cell sequencing technique. It was found that there were differences in cell proliferation, cycle, lymphocyte lineage, autophagy and JAK/STAT3 signaling pathways between young and aging HSCs. A small molecule compound Niclosamide, which approved by FDA for clinical application, was found to induce specific markers expression of young HSC in aging HSC and enhance aging HSC proliferation activity through a high throughput small molecule screening platform. Niclosamide acts as an inhibitor of JAK/STAT signaling pathway and an activator of autophagy, and also has effects on cell proliferation, cycle and other cellular activities. Therefore, we hypothesize that Niclosamide affects autophagy and cell cycle through JAK/STAT pathway, and improve the functional deficiency of aging HSC. Based on the differences between young and aging HSC, we found Niclosamide can improve the functional deficiency of aging HSC and explored its mechanism, which will lay a foundation for the wider application of aging HSC in clinical practice.

造血干细胞（Hematopoietic stem cell, HSC）衰老引起的偏向髓系发育和造血重建功能缺陷是干细胞研究的热点问题。本研究利用单细胞测序绘制了年轻（8周龄）和衰老（18月龄）小鼠骨髓来源Lineage-Scal+c-Kit+的HSC转录组图谱，发现年轻和衰老的HSC在细胞周期、自噬和JAK/STAT通路等方面存在显著差异，并进一步通过小分子筛选平台发现经Niclosamide处理后的衰老HSC可表达年轻HSC特异性标记，并且其增殖活性增强。由于Niclosamide是JAK/STAT抑制剂和自噬激活剂，并对细胞周期有影响，因此我们假设Niclosamide通过JAK/STAT通路影响细胞的自噬和周期进而改善衰老HSC的功能缺陷。本项目以年轻和衰老HSC的差异为切入点，发现Niclosamide可改善衰老HSC功能缺陷并探索其机制，这将为衰老HSC更广泛应用于临床奠定基础。

造血干细胞（Hematopoietic stem cell, HSC）衰老引起的偏向髓系分化和造血重建功能缺陷是干细胞研究的热点问题。为了探索和改善HSC衰老问题, 我们系统总结和分析了小鼠和人HSC衰老过程中自身表型及分子特征、信号通路及HSC骨髓微环境的变化和缓解HSC衰老的方法。发现在小鼠和人衰老HSC中特异性显著高表达的基因都富集到了肿瘤坏死因子(Tumor necrosis factor, TNF)等炎症通路，且TNFα和IL-1α/β等小分子抑制剂恢复了衰老HSC的部分功能，如增加了衰老HSC向淋系B细胞的分化。相关工作以第一作者身份发表在2020年的《Journal of Hematology & Oncology》、2021年的《Frontiers in Genetics》和《Signal Transduction and Targeted Therapy》上。为了进一步探索氯硝柳胺（Niclosamide）的作用和逆转衰老HSC的功能，我们首先系统总结了Niclosamide在肿瘤、炎症疾病和病毒感染3类疾病中的研究进展，并从核因子κB、信号转导和转录激活因子3（STAT3）和哺乳动物雷帕霉素靶蛋白复合物1等通路分析其诱导肿瘤细胞凋亡和降低炎症分子机制，相关工作已被《中国药理学与毒理学杂志》接收。在此基础上，通过细胞共培养和细胞因子检测我们发现Niclosamide在体外可以降低老年小鼠骨髓微环境中IL-1β、IL-6和TNFα等炎症因子的表达水平，且下调CXCL2，CXCLL4和IL1R2等炎症基因的表达。另一方面，通过灌胃老年小鼠发现Niclosamide在体内可抑制衰老HSC的髓系（单核和粒细胞等）偏向分化，促进衰老HSC向淋系，尤其是B系分化。体内外Niclosamide相关样本已经收集完整，正在准备进行单细胞测序解析Niclosamide改善衰老HSC的机制。由于Niclosamide作为一种临床上治疗肠道绦虫的药物，我们还尝试了肠道菌群改善衰老HSC功能的研究，相关工作以共同第一作者身份发表在《Blood》杂志上。同时，结合嵌合抗原受体思路，尝试了靶向清除衰老细胞等前瞻性工作，并获得2022年国际基因工程机器大赛银牌。综上所述，本项目将为Niclosamide改善HSC功能及衰老HSC更广泛应用于临床奠定夯实基础。