Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States.
Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO, United States.
Front Immunol. 2022 Oct 20;13:1038349. doi: 10.3389/fimmu.2022.1038349. eCollection 2022.
is a major human pathogen that colonizes the gastric mucosa and plays a causative role in development of peptic ulcers and gastric cancer. Neutrophils are heavily infected with this organism and play a prominent role in tissue destruction and disease. Recently, we demonstrated that exploits neutrophil plasticity as part of its virulence strategy eliciting N1-like subtype differentiation that is notable for profound nuclear hypersegmentation. We undertook this study to test the hypothesis that hypersegmentation may enhance neutrophil migratory capacity. However, EZ-TAXIScan™ video imaging revealed a previously unappreciated and progressive chemotaxis defect that was apparent prior to hypersegmentation onset. Cell speed and directionality were significantly impaired to fMLF as well as C5a and IL-8. Infected cells oriented normally in chemotactic gradients, but speed and direction were impaired because of a uropod retraction defect that led to cell elongation, nuclear lobe trapping in the contracted rear and progressive narrowing of the leading edge. In contrast, chemotactic receptor abundance, adhesion, phagocytosis and other aspects of cell function were unchanged. At the molecular level, phenocopied the effects of Blebbistatin as indicated by aberrant accumulation of F-actin and actin spikes at the uropod together with enhanced ROCKII-mediated phosphorylation of myosin IIA regulatory light chains at S19. At the same time, RhoA and ROCKII disappeared from the cell rear and accumulated at the leading edge whereas myosin IIA was enriched at both cell poles. These data suggest that inhibits the dynamic changes in myosin IIA contractility and front-to-back polarity that are essential for chemotaxis. Taken together, our data advance understanding of PMN plasticity and pathogenesis.
幽门螺杆菌是一种主要的人类病原体,定植于胃黏膜,在消化性溃疡和胃癌的发展中起致病作用。中性粒细胞被这种病原体大量感染,并在组织破坏和疾病中起重要作用。最近,我们证明幽门螺杆菌利用中性粒细胞的可塑性作为其毒力策略的一部分,引发 N1 样亚型分化,其特征是核极度分段。我们进行这项研究是为了检验假说,即极度分段可能增强中性粒细胞的迁移能力。然而,EZ-TAXIScan™视频成像揭示了一种以前未被认识到的进行性趋化缺陷,这种缺陷在极度分段出现之前就已经明显存在。细胞的速度和方向性对 fMLF 以及 C5a 和 IL-8 的影响明显受损。受感染的细胞在趋化梯度中正常定向,但由于尾足回缩缺陷导致速度和方向受损,从而导致细胞伸长、细胞核叶被困在收缩的后部,并导致前缘逐渐变窄。相比之下,趋化受体丰度、黏附、吞噬作用和细胞功能的其他方面没有变化。在分子水平上,幽门螺杆菌表现出与 Blebbistatin 相似的作用,表现为尾足处 F-肌动蛋白和肌动蛋白刺的异常积累,以及 ROCKII 介导的肌球蛋白 IIA 调节轻链 S19 磷酸化增强。同时,RhoA 和 ROCKII 从细胞后部消失并聚集在前缘,而肌球蛋白 IIA 在细胞两极都富集。这些数据表明,幽门螺杆菌抑制了肌球蛋白 IIA 收缩性和前后极性的动态变化,这对趋化作用至关重要。总之,我们的数据增进了对 PMN 可塑性和发病机制的理解。