Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
PLoS Biol. 2023 Aug 1;21(8):e3002209. doi: 10.1371/journal.pbio.3002209. eCollection 2023 Aug.
The opportunistic pathogen Pseudomonas aeruginosa causes antibiotic-recalcitrant pneumonia by forming biofilms in the respiratory tract. Despite extensive in vitro experimentation, how P. aeruginosa forms biofilms at the airway mucosa is unresolved. To investigate the process of biofilm formation in realistic conditions, we developed AirGels: 3D, optically accessible tissue-engineered human lung models that emulate the airway mucosal environment. AirGels recapitulate important factors that mediate host-pathogen interactions including mucus secretion, flow and air-liquid interface (ALI), while accommodating high-resolution live microscopy. With AirGels, we investigated the contributions of mucus to P. aeruginosa biofilm biogenesis in in vivo-like conditions. We found that P. aeruginosa forms mucus-associated biofilms within hours by contracting luminal mucus early during colonization. Mucus contractions facilitate aggregation, thereby nucleating biofilms. We show that P. aeruginosa actively contracts mucus using retractile filaments called type IV pili. Our results therefore suggest that, while protecting epithelia, mucus constitutes a breeding ground for biofilms.
机会性病原体铜绿假单胞菌通过在呼吸道形成生物膜引起对抗生素有抗药性的肺炎。尽管进行了广泛的体外实验，但铜绿假单胞菌在气道黏膜上形成生物膜的过程仍未解决。为了在真实条件下研究生物膜形成的过程，我们开发了 AirGels：3D，光学上可访问的组织工程化的人类肺模型，模拟气道黏膜环境。AirGels 再现了介导宿主-病原体相互作用的重要因素，包括粘液分泌、流动和气液界面 (ALI)，同时适应高分辨率活显微镜检查。使用 AirGels，我们在类似于体内的条件下研究了粘液对铜绿假单胞菌生物膜生物发生的贡献。我们发现，铜绿假单胞菌在定植早期通过收缩管腔粘液，在数小时内形成粘液相关生物膜。粘液收缩有助于聚集，从而成核生物膜。我们表明，铜绿假单胞菌使用称为 IV 型菌毛的可回缩丝主动收缩粘液。因此，我们的研究结果表明，尽管粘液保护上皮细胞，但它构成了生物膜的滋生地。
