PDF(Pubmed)
Abstract：
BACKGROUND: Hematopoiesis in mammal is a complex and highly regulated process in which hematopoietic stem cells (HSCs) give rise to all types of differentiated blood cells. Previous studies have shown that hairy and enhancer of split (HES) repressors are essential regulators of adult HSC development downstream of Notch signaling.
METHODS: In this study, we investigated the role of HES1, a member of HES family, in fetal hematopoiesis using an embryonic hematopoietic specific Hes1 conditional knockout mouse model by using phenotypic flow cytometry, histopathology analysis, and functional in vitro colony forming unit (CFU) assay and in vivo bone marrow transplant (BMT) assay.
RESULTS: We found that loss of Hes1 in early embryonic stage leads to smaller embryos and fetal livers, decreases hematopoietic stem progenitor cell (HSPC) pool, results in defective multi-lineage differentiation. Functionally, fetal hematopoietic cells deficient for Hes1 exhibit reduced in vitro progenitor activity and compromised in vivo repopulation capacity in the transplanted recipients. Further analysis shows that fetal hematopoiesis defects in Hes1fl/flFlt3Cre embryos are resulted from decreased proliferation and elevated apoptosis, associated with de-repressed HES1 targets, p27 and PTEN in Hes1-KO fetal HSPCs. Finally, pharmacological inhibition of p27 or PTEN improves fetal HSPCs function both in vitro and in vivo.
CONCLUSIONS: Together, our findings reveal a previously unappreciated role for HES1 in regulating fetal hematopoiesis, and provide new insight into the differences between fetal and adult HSC maintenance.
METHODS: In this study, we investigated the role of HES1, a member of HES family, in fetal hematopoiesis using an embryonic hematopoietic specific Hes1 conditional knockout mouse model by using phenotypic flow cytometry, histopathology analysis, and functional in vitro colony forming unit (CFU) assay and in vivo bone marrow transplant (BMT) assay.
RESULTS: We found that loss of Hes1 in early embryonic stage leads to smaller embryos and fetal livers, decreases hematopoietic stem progenitor cell (HSPC) pool, results in defective multi-lineage differentiation. Functionally, fetal hematopoietic cells deficient for Hes1 exhibit reduced in vitro progenitor activity and compromised in vivo repopulation capacity in the transplanted recipients. Further analysis shows that fetal hematopoiesis defects in Hes1fl/flFlt3Cre embryos are resulted from decreased proliferation and elevated apoptosis, associated with de-repressed HES1 targets, p27 and PTEN in Hes1-KO fetal HSPCs. Finally, pharmacological inhibition of p27 or PTEN improves fetal HSPCs function both in vitro and in vivo.
CONCLUSIONS: Together, our findings reveal a previously unappreciated role for HES1 in regulating fetal hematopoiesis, and provide new insight into the differences between fetal and adult HSC maintenance.
摘要：
背景：哺乳动物中的造血是一个复杂且高度调节的过程，其中造血干细胞（HSC）产生所有类型的分化血细胞。先前的研究表明，毛状和分裂增强子（HES）抑制因子是Notch信号传导下游成年HSC发育的重要调节因子。
方法：在本研究中，我们研究了HES家族成员HES1的作用，在胎儿造血中，使用表型流式细胞术使用胚胎造血特异性Hes1条件敲除小鼠模型，组织病理学分析,和功能性体外集落形成单位（CFU）测定和体内骨髓移植（BMT）测定。
结果：我们发现胚胎早期阶段Hes1的缺失导致胚胎和胎儿肝脏变小，减少造血干祖细胞（HSPC）池，导致多谱系分化缺陷。功能上,缺乏Hes1的胎儿造血细胞在移植受体中表现出体外祖细胞活性降低和体内再增殖能力受损。进一步分析表明,Hes1fl/flFlt3Cre胚胎中的胎儿造血缺陷是由于增殖减少和细胞凋亡升高所致,与去抑制的HES1目标相关，P27和PTEN在Hes1-KO胎儿HSPCs中的表达。最后,p27或PTEN的药理学抑制可改善胎儿HSPCs的体外和体内功能.
结论：一起，我们的发现揭示了HES1在调节胎儿造血中以前未被重视的作用，并为胎儿和成人HSC维持之间的差异提供新的见解。
方法：在本研究中，我们研究了HES家族成员HES1的作用，在胎儿造血中，使用表型流式细胞术使用胚胎造血特异性Hes1条件敲除小鼠模型，组织病理学分析,和功能性体外集落形成单位（CFU）测定和体内骨髓移植（BMT）测定。
结果：我们发现胚胎早期阶段Hes1的缺失导致胚胎和胎儿肝脏变小，减少造血干祖细胞（HSPC）池，导致多谱系分化缺陷。功能上,缺乏Hes1的胎儿造血细胞在移植受体中表现出体外祖细胞活性降低和体内再增殖能力受损。进一步分析表明,Hes1fl/flFlt3Cre胚胎中的胎儿造血缺陷是由于增殖减少和细胞凋亡升高所致,与去抑制的HES1目标相关，P27和PTEN在Hes1-KO胎儿HSPCs中的表达。最后,p27或PTEN的药理学抑制可改善胎儿HSPCs的体外和体内功能.
结论：一起，我们的发现揭示了HES1在调节胎儿造血中以前未被重视的作用，并为胎儿和成人HSC维持之间的差异提供新的见解。
