Division of Neuro-Oncology, Experimental Infectious Diseases and Cancer Research, Oncology Department, University Children's Hospital Zürich, Zürich, Switzerland.
PLoS One. 2013 Sep 24;8(9):e75577. doi: 10.1371/journal.pone.0075577. eCollection 2013.
Recent technical advances have broadened our understanding of processes that govern mammalian cell migration in health and disease but many of the molecular and morphological alterations that precede and accompany movement of cells - in particular in three-dimensional (3D) environments - are still incompletely understood. In this manuscript, using high-resolution and time-lapse microscopy imaging approaches, we describe morphodynamic processes during rounded/amoeboid cell invasion and molecules associated with the cellular invasion structures. We used macrophages infected with the intracellular protozoan parasite Theileria annulata, which causes Tropical Theileriosis in susceptible ruminants such as domestic cattle. T. annulata transforms its host cell that, as a result, acquires many characteristics of human cancer cells including a markedly increased potential to migrate, disseminate and expand in the body of the host animal. Hence, virulence of the disease is associated with the capability of infected cells to disseminate inside the host. Using T. annulata-transformed macrophages as a model system, we described a novel mode of rounded/amoeboid macrophage migration. We show that filopodia-like membrane extensions at the leading edge lead the way and further evolve in blebbing membrane protrusions to promote progressive expansion of the matrix. Associated with focal invasion structures we detected ezrin, radixin, moesin-family proteins and their regulatory kinase MAP4K4. Furthermore, we linked Rho-kinase activity to contractile force generation, which is essential for infected cell motility. Thus, the motility mode of these parasite-transformed macrophages contrasts with those described so far in human macrophages such as the tunneling or mesenchymal modes, which require engulfment, compaction and ingestion of matrix or proteolytic matrix degradation, respectively. Together, our data reveal protrusion dynamics at the leading edge of invading cells in 3D at unprecedented temporal and spatial resolution and suggest a novel mode of rounded/amoeboid invasive cell motility that exploits actin-driven filopodia formation in combination with pressure-driven membrane blebs.
最近的技术进步拓宽了我们对健康和疾病中控制哺乳动物细胞迁移的过程的理解，但许多在细胞运动之前和伴随运动的分子和形态改变 - 特别是在三维（3D）环境中 - 仍然不完全理解。在本手稿中，我们使用高分辨率和延时显微镜成像方法，描述了圆形/阿米巴样细胞入侵期间的形态动力学过程以及与细胞入侵结构相关的分子。我们使用感染了细胞内原生动物寄生虫泰勒虫的巨噬细胞，这种寄生虫会导致热带泰勒病，易感反刍动物如家养牛会感染这种疾病。泰勒虫会改变其宿主细胞，因此宿主细胞获得了许多人类癌细胞的特征，包括显著增加的迁移、扩散和在宿主动物体内扩张的潜力。因此，疾病的毒力与感染细胞在宿主体内扩散的能力有关。我们使用泰勒虫转化的巨噬细胞作为模型系统，描述了一种新型的圆形/阿米巴样巨噬细胞迁移模式。我们表明，在前沿的类丝状伪足样膜延伸物引导并进一步演变成泡状膜突起，以促进基质的渐进性扩张。与局灶性入侵结构相关，我们检测到 ezrin、radixin、moesin 家族蛋白及其调节激酶 MAP4K4。此外，我们将 Rho-kinase 活性与收缩力产生联系起来，这对于感染细胞的运动是必不可少的。因此，这些寄生虫转化的巨噬细胞的运动模式与迄今为止在人类巨噬细胞中描述的模式（如隧道或间充质模式）形成对比，后两者分别需要吞噬、压实和摄取基质或蛋白水解基质降解。总之，我们的数据以前所未有的时空分辨率揭示了 3D 中入侵细胞前沿的突起动力学，并提出了一种新的圆形/阿米巴样入侵细胞运动模式，该模式利用肌动蛋白驱动的丝状伪足形成与压力驱动的膜泡相结合。
