ABSTRACT In this study, we investigated the effects of specific low-frequency electromagnetic field sequences on U937 cells, an in vitro model of human monocyte/macrophage differentiation. U937 cells were exposed to electromagnetic stimulation by means of the SynthéXer system using two similar sequences, XR-BC31 and XR-BC31/F. Each sequence was a time series of 29 wave segments, equal to a total duration of 77 min. Here, we report that exposure (4 d, once a day) of U937 cells to the XR-BC31 setting, but not to the XR-BC31/F, resulted in increased expression of the histone demethylase KDM6B along with a global reduction in histone H3 lysine 27 tri-methylation (H3K27me3). Furthermore, exposure to the XR-BC31 sequence induced differentiation of U937 cells towards a macrophage-like phenotype displaying a KDM6B dependent increase in expression and secretion of the anti-inflammatory interleukins (ILs), IL-10 and IL-4. Importantly, all the observed changes were highly dependent on the nature of the sequence. Our results open a new way of interpretation for the effects of low-frequency electromagnetic fields observed in vivo. Indeed, it is conceivable that a specific low-frequency electromagnetic fields treatment may cause the reprogramming of H3K27me3 and cell differentiation.

中文翻译：

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特定的低频电磁场诱导与 U937 细胞功能变化相关的活性 KDM6B 的表达

摘要 在这项研究中，我们研究了特定低频电磁场序列对 U937 细胞的影响，U937 细胞是人类单核细胞/巨噬细胞分化的体外模型。U937 细胞通过 SynthéXer 系统使用两个相似的序列 XR-BC31 和 XR-BC31/F 暴露于电磁刺激。每个序列是 29 个波段的时间序列，等于 77 分钟的总持续时间。在这里，我们报告将 U937 细胞暴露于 XR-BC31 环境（4 天，每天一次），而不是 XR-BC31/F，导致组蛋白去甲基化酶 KDM6B 的表达增加以及组蛋白的整体减少H3 赖氨酸 27 三甲基化 (H3K27me3)。此外，暴露于 XR-BC31 序列诱导 U937 细胞向巨噬细胞样表型分化，显示抗炎性白细胞介素 (IL)、IL-10 和 IL-4 的表达和分泌的 KDM6B 依赖性增加。重要的是，所有观察到的变化都高度依赖于序列的性质。我们的结果为体内观察到的低频电磁场的影响开辟了一种新的解释方式。事实上，可以想象特定的低频电磁场治疗可能会导致 H3K27me3 的重编程和细胞分化。我们的结果为体内观察到的低频电磁场的影响开辟了一种新的解释方式。事实上，可以想象特定的低频电磁场治疗可能会导致 H3K27me3 的重编程和细胞分化。我们的结果为体内观察到的低频电磁场的影响开辟了一种新的解释方式。事实上，可以想象特定的低频电磁场治疗可能会导致 H3K27me3 的重编程和细胞分化。