Direct current electric field exposure changes the conformational dynamics of IL-1β in RAW 264.7 macrophages

Wearable devices have led to a growing interest in the effects of physical stimuli, such as electric fields (EF), on cells. However, the impact of EF on macrophages remains largely unexplored. To address this gap, we developed an electric-field chamber that applies direct current electric field (dcEF) to RAW 264.7 macrophages and analyzed the transcriptome changes and IL-1β protein conformation dynamics. Our results showed that exposure to dcEF did not affect cell morphology but significantly reduced cell viability. RNA-seq analysis revealed that dcEF altered the expression of 3518 upregulated and 2,531 downregulated genes. We also identified 6 hub genes using PPI network analysis and qPCR test. In addition, WB results suggested that dcEF increased the expression level of IL-1β. Next, we used molecular dynamics (MD) simulations to investigate the impact of dcEF on the conformation of the IL-1β protein. Our analysis results indicate that the dcEF’s intensity significantly impacts various aspects of protein behavior, including its structure, motion, hydrogen bonding, and dipole moment. The alpha-helix structure exhibited the earliest degradation when exposed to an electric field, destroying other natural structures. In addition, the results of interleukin-1 (IL-1) gene family analysis suggest that this gene family is evolutionarily highly conserved. Overall, our findings provide insights into the influence of dcEF on macrophages and suggest potential applications of dcEF in cell biology and medicine.

可穿戴设备的兴起，使得学界对电场（Electric Field, EF）等物理刺激对细胞的作用愈发关注。然而，电场对巨噬细胞的影响迄今仍未得到充分探索。为填补这一研究空白，我们研发了一款电场培养腔，可向RAW 264.7巨噬细胞施加直流电场（Direct Current Electric Field, dcEF），并对其转录组变化及IL-1β蛋白构象动力学展开分析。研究结果显示，直流电场暴露不会改变细胞形态，但会显著降低细胞存活率。RNA测序（RNA-seq）分析表明，直流电场调控了3518个上调基因与2531个下调基因的表达。我们还通过蛋白质相互作用（Protein-Protein Interaction, PPI）网络分析与实时定量聚合酶链反应（quantitative polymerase chain reaction, qPCR）实验，筛选出6个枢纽基因。此外，蛋白质印迹（Western Blot, WB）实验结果显示，直流电场可提升IL-1β的表达水平。随后，我们借助分子动力学（Molecular Dynamics, MD）模拟技术，探究了直流电场对IL-1β蛋白构象的影响。分析结果表明，直流电场的强度会显著影响蛋白行为的多个维度，包括其结构、运动状态、氢键作用与偶极矩。α螺旋结构在电场暴露下最早发生降解，进而破坏其他天然结构。此外，白细胞介素-1（IL-1）基因家族分析结果显示，该基因家族在进化层面具有高度保守性。综上，本研究结果为解析直流电场对巨噬细胞的影响提供了新视角，并提示直流电场在细胞生物学与医学领域具备潜在应用价值。