Human monocytes and macrophages differ in their mechanisms of adaptation to hypoxia
Human monocytes and macrophages differ in their mechanisms of adaptation to hypoxia
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DOI：
10.1186/ar4011
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发表时间：
2012-01-01
影响因子：
4.9
通讯作者：
Buttgereit, Frank
中科院分区：
文献类型：
--
作者：
Fangradt, Monique;Hahne, Martin;Buttgereit, Frank
前言：炎性关节炎是以关节慢性炎症为主要特征的进行性疾病，以免疫细胞浸润和滑膜过度增殖为主要特征。单核细胞向炎症区域迁移并分化为巨噬细胞。在发炎的组织中，与外周血液相比，氧气水平(缺氧)要低得多。因此，必须进行代谢适应过程。其他研究表明，缺氧诱导因子1-α(HIF-1α)可能调节这一过程，但涉及到人类单核细胞的机制尚不清楚。为了解决这个问题，我们分析了HIF-1α在单核细胞和巨噬细胞中的表达和功能，同时也考虑了B细胞中kappa轻多肽基因增强子核因子(NF Kappa B)的替代途径。方法：分离的人CD14(+)单核细胞分别在常氧和低氧条件下孵育，并分别在佛波酯(PMA)刺激或不加佛波醇(PMA)刺激下进行培养。制备胞核和胞浆部分，免疫印迹法检测HIF-1α和NF-kappaB。在巨噬细胞实验中，利用人巨噬细胞集落刺激因子(HM-CSF)将原代人单核细胞分化为人单核细胞来源的巨噬细胞(HMDM)。结果：利用原代人单核细胞和HMDM，我们证明了转录因子HIF-1α在分化过程中的定位从胞浆(单核细胞)转移到核(巨噬细胞)，显然是对低氧环境的适应。在这种定位变化中，蛋白激酶Cα/β1(PKC-α/β(1))起着重要的作用。在单核细胞中，对低氧调节基因表达起核心作用的是核因子kappaB1，而不是HIF-1α。结论：这些数据表明，在单核细胞向巨噬细胞分化过程中，关键的细胞适应机制发生了决定性的变化。
Introduction: Inflammatory arthritis is a progressive disease with chronic inflammation of joints, which is mainly characterized by the infiltration of immune cells and synovial hyperproliferation. Monocytes migrate towards inflamed areas and differentiate into macrophages. In inflamed tissues, much lower oxygen levels (hypoxia) are present in comparison to the peripheral blood. Hence, a metabolic adaptation process must take place. Other studies suggest that Hypoxia Inducible Factor 1-alpha (HIF-1 alpha) may regulate this process, but the mechanism involved for human monocytes is not yet clear. To address this issue, we analyzed the expression and function of HIF-1 alpha in monocytes and macrophages, but also considered alternative pathways involving nuclear factor of kappa light polypeptide gene enhancer in B-cells (NF kappa B).Methods: Isolated human CD14(+) monocytes were incubated under normoxia and hypoxia conditions with or without phorbol 12-myristate 13-acetate (PMA) stimulation, respectively. Nuclear and cytosolic fractions were prepared in order to detect HIF-1 alpha and NF kappa B by immunoblot. For the experiments with macrophages, primary human monocytes were differentiated into human monocyte derived macrophages (hMDM) using human macrophage colony-stimulating factor (hM-CSF). The effects of normoxia and hypoxia on gene expression were compared between monocytes and hMDMs using quantitative PCR (quantitative polymerase chain reaction).Results: We demonstrate, using primary human monocytes and hMDM, that the localization of transcription factor HIF-1 alpha during the differentiation process is shifted from the cytosol (in monocytes) into the nucleus (in macrophages), apparently as an adaptation to a low oxygen environment. For this localization change, protein kinase C alpha/beta 1 (PKC-alpha/beta(1)) plays an important role. In monocytes, it is NF kappa B1, and not HIF-1 alpha, which is of central importance for the expression of hypoxia-adjusted genes.Conclusions: These data demonstrate that during differentiation of monocytes into macrophages, crucial cellular adaptation mechanisms are decisively changed.