CCAAT/enhancer-binding proteins are required for granulopoiesis independent of their induction of the granulocyte colony-stimulating factor receptor
CCAAT/enhancer-binding proteins are required for granulopoiesis independent of their induction of the granulocyte colony-stimulating factor receptor
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DOI：
10.1182/blood.v99.8.2776
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发表时间：
2002-04-15
期刊：
影响因子：
20.3
通讯作者：
Friedman, AD
中科院分区：
文献类型：
--
作者：
Wang, QF;Friedman, AD
骨髓细胞中 CCAAT/增强子结合蛋白 (C/EBP) 家族成员之间的潜在冗余通过 C/EBPbeta 在体内替代 C/EBPα 的能力、C/EBPα(-/-) 细胞系上粒细胞集落刺激因子受体 (G-CSFR) 的表达以及我们的发现与 C/EBPα-雌激素受体 (C/EBPα-ER) 一样，表明C/EBPbeta-ER 或 C/EBPdelta-ER 可诱导 32D c13 细胞的终末粒细胞生成。为了评估全局抑制 C/EBP 的后果，我们使用了 KaalphaER，它包含 Kruppel 相关盒 (KRAB) 反式阻抑结构域、C/EBPalpha DNA 结合结构域和 ER 配体结合结构域。 C/EBP 具有共同的 DNA 结合共识，KalphaER 的激活可将内源性 C-/EBP 的反式激活抑制 50 倍，并减少内源性 G-CSFR 的表达。在共表达外源 G-CSFR 的 32D c13 细胞中，KalphaER 的激活阻止甚至逆转 G-CSF 诱导的髓过氧化物酶、溶菌酶、乳铁蛋白和 C/EBPepsilon RNA。相反，PU.1 和 CD11b（受 PU.1 但不受 C/EBP 调控的基因）的诱导不受影响。由于亮氨酸拉链改变而无法结合 DNA 的 KalphaER 变体不会影响 32D c13 分化。将KalphaER转导至小鼠造血祖细胞中可抑制粒细胞集落形成单位的形成，甚至在使C/EBPα(-/-)祖细胞分化为中性粒细胞的细胞因子中也是如此。巨噬细胞和粒细胞-巨噬细胞集落形成单位的形成也受到抑制，但红细胞爆发形成单位正常生长。因此，在 32D c13 细胞和可能的正常祖细胞中，C/EBP 是粒细胞生成所必需的，超出了它们诱导 G-CSF 和其他细胞因子受体的能力。一种必需的活性可能是 C/EBPα 激活 C/EBPepsilon 基因，因为在放线菌酮存在但放线菌素 D 不存在的情况下，C/EBPα-ER 或 C/EBPbeta-ER 会快速升高 32D c13 细胞中的 C/EBPepsilon RNA。 (C) 2002，美国血液学会。
Potential redundancy among members of the CCAAT/enhancer-binding protein (C/EBP) family in myeloid cells is indicated by the ability of C/EBPbeta to replace C/EBPalpha in vivo, by the expression of granulocyte colony-stimulating factor receptor (G-CSFR) on C/EBPalpha(-/-) cell lines, and by our finding that as with C/EBPalpha-estrogen receptor (C/EBPalpha-ER), either C/EBPbeta-ER or C/EBPdelta-ER can induce terminal granulopoiesis in 32D c13 cells. To assess the consequences of globally inhibiting C/EBPs, we employed KalphaER, containing a Kruppel-associated box (KRAB) transrepression domain, the C/EBPalpha DNA-binding domain, and an ER ligand-binding domain. C/EBPs have a common DNA-binding consensus, and activation of KalphaER repressed transactivation by endogenous C-/EBPs 50-fold and reduced endogenous G-CSFR expression. In 32D c13 cells coexpressing exogenous G-CSFR, activation of KalphaER prevented and even reversed myeloperoxidase, lysozyme, lactoferrin, and C/EBPepsilon RNA induction by G-CSF. In contrast, induction of PU.1 and CD11b, a gene regulated by PU.1 but not by C/EBPs, was unaffected. A KalphaER variant incapable of binding DNA owing to an altered leucine zipper did not affect 32D c13 differentiation. Transduction of KalphaER into murine hematopoietic progenitor cells suppressed the formation of granulocyte colony-forming units, even in cytokines that enable C/EBPalpha(-/-) progenitors to differentiate into neutrophils. The formation of macrophage and of granulocyte-macrophage colony-forming units were also inhibited, but erythroid burst-forming units grew normally. Thus, In 32D c13 cells and perhaps normal progenitors, C/EBPs are required for granulopoiesis beyond their ability to induce receptors for G-CSF and other cytokines. One requisite activity may be activation of the C/EBPepsilon gene by C/EBPalpha, as either C/EBPalpha-ER or C/EBPbeta-ER rapidly elevated C/EBPepsilon RNA in 32D c13 cells in the presence of cycloheximide but not actinomycin D. (C) 2002 by The American Society of Hematology.