Air Force Medical University, Xi'an, China.
Xiamen Special Service Health Center of the Army, Xiamen, China.
Arch Biochem Biophys. 2021 May 30;703:108846. doi: 10.1016/j.abb.2021.108846. Epub 2021 Mar 17.
CCAAT/enhancer-binding protein β (C/EBPβ) is a transcription factor that is involved in adipocytic and monocytic differentiation. However, the physiological role of C/EBPβ in megakaryocytes (MKs) is not clear. In this study, we investigated the effects of C/EBPβ on the early-stage differentiation of MKs, and explored the potential mechanisms of action. We established a cytosine arabinoside-induced thrombocytopenia mouse model using C57BL/6 mice. In the thrombocytopenia mice, the platelet count was found to be decreased, and the mRNA and protein expression levels of C/EBPβ in MKs were also reduced. Furthermore, the maturation of Dami (MKs cell line) cells was induced by phorbol 12-myristate 13-acetate. When C/EBPβ was silenced in Dami cells by transfection using C/EBPβ-small interfering RNA, the expression of MKs-specific markers CD41 and CD62P, was dramatically decreased, resulting in morphological changes and differentiation retardation in low ploidy, which were evaluated using flow cytometry, real-time polymerase chain reaction, western blot, and confocal microscopy. The mitogen activated protein kinase-extracellular signal-regulated kinase signaling pathway was found to be required for the differentiation of MKs; knockdown of C/EBPβ in MEK/ERK1/2 pathway attenuated MKs differentiation. Overexpression of C/EBPβ in MEK/ERK1/2 pathway inhibited by U0126 did not promote MKs differentiation. To the best of our knowledge, C/EBPβ plays an important role in MKs differentiation and polyploidy cell cycle control. Taken together, C/EBPβ may have thrombopoietic effects in the differentiation of MKs, and may assist in the development of treatments for various disorders.
CCAAT/增强子结合蛋白 β（C/EBPβ）是一种参与脂肪细胞和单核细胞分化的转录因子。然而，C/EBPβ 在巨核细胞（MKs）中的生理作用尚不清楚。在这项研究中，我们研究了 C/EBPβ 对 MKs 早期分化的影响，并探讨了其潜在的作用机制。我们使用 C57BL/6 小鼠建立了阿糖胞苷诱导的血小板减少症小鼠模型。在血小板减少症小鼠中，血小板计数降低，MKs 中 C/EBPβ 的 mRNA 和蛋白表达水平也降低。此外，通过佛波醇 12-肉豆蔻酸 13-乙酸酯诱导 Dami（MKs 细胞系）细胞成熟。当通过 C/EBPβ 小干扰 RNA 转染沉默 Dami 细胞中的 C/EBPβ 时，MKs 特异性标志物 CD41 和 CD62P 的表达显著降低，导致低倍体的形态变化和分化延迟，通过流式细胞术、实时聚合酶链反应、western blot 和共聚焦显微镜进行评估。有丝分裂原激活蛋白激酶-细胞外信号调节激酶信号通路被发现是 MKs 分化所必需的；MEK/ERK1/2 通路中 C/EBPβ 的敲低减弱了 MKs 的分化。在 U0126 抑制的 MEK/ERK1/2 通路中过表达 C/EBPβ 并没有促进 MKs 的分化。据我们所知，C/EBPβ 在 MKs 分化和多倍体细胞周期控制中起重要作用。综上所述，C/EBPβ 在 MKs 的分化中具有促血小板生成作用，并可能有助于开发治疗各种疾病的方法。
