Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan.
Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Japan.
J Leukoc Biol. 2020 May;107(5):819-831. doi: 10.1002/JLB.2A0320-110RR. Epub 2020 Apr 17.
High-level reactive oxygen species (ROS) production in neutrophils is tightly regulated, as it can damage host cells. Neutrophils also undergo low-level ROS production when stimulated by cytokines or chemoattractants, but its biologic significance remains largely unknown. Voltage-gated proton channels (Hv1/VSOP) activity reportedly supports ROS production in neutrophils; however, we show here that Hv1/VSOP balances ROS production to suppress neutrophil directional migration in the presence of low concentrations of N-formyl-Met-Leu-Phe (fMLF). Neutrophils derived from Hvcn1 gene knockout mice produced more ROS than neutrophils from wild-type mice in the stimulation with fMLF at concentration of 1 µM and nonstimulus condition. They also exhibited stronger chemotactic responses to low concentrations of fMLF than did wild-type neutrophils. Receptor sensitivity to fMLF and evoked Ca responses did not differ between Hv1/VSOP-deficient and wild-type neutrophils. Activation of ERK, but not p38, was enhanced and prolonged during the increased ROS production seen after fMLF stimulation in Hv1/VSOP-deficient neutrophils. Inhibiting ROS production suppressed the enhanced ERK activation in Hv1/VSOP-deficient neutrophils and their directional migration. These results indicate that Hv1/VSOP balances ROS production to reduce ERK signaling and suppress excessive neutrophil migration in response to fMLF. Our findings thus reveal a novel role for ROS in the directional migration of neutrophils.
中性粒细胞中高水平的活性氧（ROS）的产生受到严格调控，因为它会损害宿主细胞。当受到细胞因子或趋化因子刺激时，中性粒细胞也会产生低水平的 ROS，但它的生物学意义在很大程度上仍不清楚。据报道，电压门控质子通道（Hv1/VSOP）的活性支持中性粒细胞中 ROS 的产生；然而，我们在这里表明，Hv1/VSOP 平衡 ROS 的产生，以抑制低浓度 N-甲酰基-Met-Leu-Phe（fMLF）存在时中性粒细胞的定向迁移。与野生型小鼠的中性粒细胞相比，Hvcn1 基因敲除小鼠的中性粒细胞在 1µM fMLF 刺激和非刺激条件下产生更多的 ROS。它们对低浓度 fMLF 的趋化反应也比野生型中性粒细胞更强。Hv1/VSOP 缺陷型和野生型中性粒细胞对 fMLF 的受体敏感性和诱发的 Ca 反应没有差异。与野生型中性粒细胞相比，在 Hv1/VSOP 缺陷型中性粒细胞中，ERK 的激活增强且持续时间延长，而在 fMLF 刺激后 ROS 产生增加时。抑制 ROS 的产生抑制了 Hv1/VSOP 缺陷型中性粒细胞中增强的 ERK 激活及其定向迁移。这些结果表明，Hv1/VSOP 平衡 ROS 的产生以减少 ERK 信号传导并抑制对 fMLF 的过度中性粒细胞迁移。因此，我们的研究结果揭示了 ROS 在中性粒细胞定向迁移中的新作用。
