G-CSF-dependent de-/acetylation of myeloid-specific transcription factors LEF 1 and C/EBPalpha in myeloid differentiation and leukemogenesis

G-CSF是粒细胞生成的主要调节因子，诱导造血干细胞向粒细胞和单核细胞的增殖和分化。G-CSFR信号传导失败可导致两种血液学疾病：严重先天性中性粒细胞减少症（CN）和急性髓性白血病（AML）。在CN患者中，髓系祖细胞不能分化为粒细胞。在AML中，造血干细胞失去了分化能力并表现出不受控制的增殖。超过90%的CN患者对高药理学剂量的G-CSF（高达80微克/千克/天）有反应。CN是一种白血病前期综合征，约25%的患者发展为AML。假设G-CSFR信号参与白血病发生，80%的CN/AML患者获得G-CSFR突变。蛋白质翻译后的去乙酰化修饰对其功能很重要，但研究仍然很少。同样不清楚的是，g - csfr引发的髓细胞分化是否需要髓细胞特异性信号蛋白的去乙酰化。分析CN、CN/AML和新生AML患者中转录因子的去乙酰化，并与健康个体进行比较，可能有助于描述在髓细胞分化或白血病发生过程中运作的新信号系统。我们的目标是：(1)研究髓细胞特异性转录因子LEF-1及其靶基因C/EBPalpha的去乙酰化在髓细胞分化和白血病转化中的作用；(2)分析G-CSFR/NAMPT/NAD+/SIRT系统在LEF-1和C/EBPalpha脱乙酰化中的作用(3)分析LEF-1脱乙酰化与HCLS1蛋白相互作用对其核易位的影响。我们希望通过使用NAMPT/SIRT信号的药理调节剂调节LEF-1和C/EBPalpha蛋白的去乙酰化状态，我们将能够调节LEF-1/C/EBPalpha触发的髓细胞分化和白血病转化，这可以用于治疗中性粒细胞减少症或髓细胞白血病。

G-CSF is a major regulator of granulopoiesis, inducing proliferation and differentiation of hematopoietic stem cells toward granulocytes and monocytes. Failures in G-CSFR signaling are causative for two hematological disorders: severe congenital neutropenia (CN) and AML. In CN patients, myeloid progenitor cells failed to differentiate into granulocytes. In AML, hematopoietic stem cells loose the ability to differentiate and show uncontrolled proliferation. More than 90% of CN patients respond to high pharmacological doses of G-CSF (up to 80 mcg/kg/day). CN is a pre-leukemic syndrome, ca. 25% of patients develop AML. Eighty percent of CN/AML patients have acquired G-CSFR mutations, assuming the involvement of G-CSFR signaling in leukemogenesis. Post-translational modification of proteins by de-/acetylation is important for their functions, but is still poorly investigated. It is also unclear, whether G-CSFR-triggered myeloid differentiation requires de-/acetylation of myeloid-specific signaling proteins. The analysis of the de-/acetylation of transcription factors in CN, CN/AML and de novo AML patients in comparison to healthy individuals may help to delineate new signaling systems operating during myeloid differentiation or leukemogenesis. We aim: (1) to investigate the role of de-/acetylation of myeloid-specific transcription factors LEF-1 and its target C/EBPalpha in myeloid differentiation and leukemogenic transformation; (2) to analyse the role of G-CSFR/NAMPT/NAD+/SIRT system in the de-/acetylation of LEF-1 and C/EBPalpha (3) to analyse the effects of de-/acetylation of LEF-1 for its nuclear translocation by interaction with the HCLS1 protein. We hope that by modulation of de-/acetylation status of LEF-1 and C/EBPalpha proteins using pharmacological modulators of NAMPT/SIRT signalling, we will be able to regulate LEF-1/C/EBPalpha-triggered myeloid differentiation and leukemogenic transformation, which could be used for treatment of neutropenia or myeloid leukemia.