Geiser Petra, Di Martino Maria Letizia, Lopes Ana C C, Bergholtz Alexandra, Sundbom Magnus, Skogar Martin, Graf Wilhelm, Björner Kajsa, Vessby Johan, Webb Dominic-Luc, Hellström Per M, Eriksson Jens, Sellin Mikael E
Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Uppsala County, Sweden.
Department of Surgical Sciences, Uppsala University, Uppsala, Uppsala County, Sweden.
mBio. 2025 Jul 9;16(7):e0091125. doi: 10.1128/mbio.00911-25. Epub 2025 May 30.
Despite their relatedness, and enteropathogens differ in infectious dose, pathogenesis, and disease kinetics. The prototype strains serovar Typhimurium () and () use Type-3-secretion-systems (T3SSs) to colonize intestinal epithelial cells (IECs). However, they have evolved unique sets of T3SS effectors and accessory virulence factors. A synthesis of how these differences impact the temporal progression of infection in non-transformed human epithelia is missing. Here, we followed and infections of human enteroids and colonoids by time-lapse imaging to pinpoint virulence factor modules that shape the divergent epithelial colonization strategies. By an apical targeting module that integrates flagella and the SPI-4-encoded adhesin system with T3SS-1, accomplishes appreciable numbers of apical IEC invasion events. These are promptly counteracted by IEC death, thus fostering a polyclonal iterative epithelial colonization strategy. The lack of a corresponding apical targeting module in makes this pathogen reliant on external factors, for example, preexisting damage, for rare apical access to the intraepithelial environment. However, compensates for this ineptness by an intraepithelial expansion module reliant on the tight coupling of OspC3-dependent temporal delay of cell death and IcsA-mediated mobility. This module enables intraepithelial to evade the IEC death response just long enough to expand laterally, thus fostering an essentially monoclonal colonization strategy. Taken together, the study reveals how a small set of virulence factors shapes divergent epithelial colonization strategies by related enterobacteria.IMPORTANCEPathogenic bacteria employ partially overlapping sets of virulence factor functions to colonize host epithelia but can differ markedly in their pathogenesis and disease kinetics. This work combines bacterial genetics and real-time microscopy in enteroids and colonoids to decipher the divergent colonization strategies of Typhimurium and -two major enteropathogens-in non-transformed human intestinal epithelia. The results reveal how virulence factor modules enabling efficiency at either the invasion step () or the intraepithelial expansion stage () drive the radically different infection cycles of these related enterobacteria. Moreover, our work emphasizes how real-time studies in infection models that retain primary host cell features are critical to understanding infectious disease progression.
尽管它们具有相关性，但肠道病原体在感染剂量、发病机制和疾病动力学方面存在差异。鼠伤寒沙门氏菌血清型鼠伤寒（）和（）的原型菌株利用III型分泌系统（T3SS）定殖于肠道上皮细胞（IEC）。然而，它们已经进化出独特的T3SS效应子和辅助毒力因子组合。目前尚缺乏关于这些差异如何影响未转化人上皮细胞感染时间进程的综合研究。在这里，我们通过延时成像追踪了鼠伤寒沙门氏菌和对人肠类器官和结肠类器官的感染，以确定塑造不同上皮定殖策略的毒力因子模块。通过一个将鞭毛和SPI-4编码的粘附素系统与T3SS-1整合的顶端靶向模块，鼠伤寒沙门氏菌完成了相当数量的顶端IEC侵袭事件。这些侵袭事件会迅速被IEC死亡所抵消，从而促进多克隆迭代上皮定殖策略。在中缺乏相应的顶端靶向模块，使得这种病原体依赖外部因素，例如预先存在的损伤，才能罕见地顶端进入上皮内环境。然而，通过一个依赖于OspC3依赖性细胞死亡时间延迟和IcsA介导的移动性紧密耦合的上皮内扩展模块来弥补这种不足。该模块使上皮内的能够逃避IEC死亡反应足够长的时间以进行横向扩展，从而促进一种基本上是单克隆的定殖策略。综上所述，该研究揭示了一小套毒力因子如何塑造相关肠道细菌不同的上皮定殖策略。重要性致病细菌利用部分重叠的毒力因子功能组合来定殖宿主上皮，但它们的发病机制和疾病动力学可能有显著差异。这项工作将细菌遗传学与肠类器官和结肠类器官中的实时显微镜相结合，以破译鼠伤寒沙门氏菌和这两种主要肠道病原体在未转化人肠道上皮中的不同定殖策略。结果揭示了在侵袭步骤（）或上皮内扩展阶段（）实现高效性的毒力因子模块如何驱动这些相关肠道细菌截然不同的感染周期。此外，我们的工作强调了在保留原代宿主细胞特征的感染模型中进行实时研究对于理解传染病进展的关键作用。
