A key attribute of persistent or recurring bacterial infections is the ability of the pathogen to evade the host’s immune response. Many Enterobacteriaceae express type 1 pili, a pre-adapted virulence trait, to invade host epithelial cells and establish persistent infections. However, the molecular mechanisms and strategies by which bacteria actively circumvent the immune response of the host remain poorly understood. Here, we identified CD14, the major co-receptor for lipopolysaccharide detection, on mouse dendritic cells (DCs) as a binding partner of FimH, the protein located at the tip of the type 1 pilus of Escherichia coli. The FimH amino acids involved in CD14 binding are highly conserved across pathogenic and non-pathogenic strains. Binding of the pathogenic strain CFT073 to CD14 reduced DC migration by overactivation of integrins and blunted expression of co-stimulatory molecules by overactivating the NFAT (nuclear factor of activated T-cells) pathway, both rate-limiting factors of T cell activation. This response was binary at the single-cell level, but averaged in larger populations exposed to both piliated and non-piliated pathogens, presumably via the exchange of immunomodulatory cytokines. While defining an active molecular mechanism of immune evasion by pathogens, the interaction between FimH and CD14 represents a potential target to interfere with persistent and recurrent infections, such as urinary tract infections or Crohn’s disease.
We thank Ulrich Dobrindt for providing UPEC strains CFT073, UTI89, and 536, Frank Assen, Vlad Gavra, Maximilian Götz, Bor Kavčič, Jonna Alanko, and Eva Kiermaier for help with experiments and Robert Hauschild, Julian Stopp, and Saren Tasciyan for help with data analysis. We thank the IST Austria Scientific Service Units, especially the Bioimaging facility, the Preclinical facility and the Electron microscopy facility for technical support, Jakob Wallner and all members of the Guet and Sixt lab for fruitful discussions and Daria Siekhaus for critically reading the manuscript. This work was supported by grants from the Austrian Research Promotion Agency (FEMtech 868984) to IG, the European Research Council (CoG 724373), and the Austrian Science Fund (FWF P29911) to MS.
Tomasek K, Leithner AF, Glatzová I, Lukesch MS, Guet CC, Sixt MK. Type 1 piliated uropathogenic Escherichia coli hijack the host immune response by binding to CD14. eLife. 2022;11. doi:10.7554/eLife.78995
Tomasek, K., Leithner, A. F., Glatzová, I., Lukesch, M. S., Guet, C. C., & Sixt, M. K. (2022). Type 1 piliated uropathogenic Escherichia coli hijack the host immune response by binding to CD14. ELife. eLife Sciences Publications. https://doi.org/10.7554/eLife.78995
Tomasek, Kathrin, Alexander F Leithner, Ivana Glatzová, Michael S. Lukesch, Calin C Guet, and Michael K Sixt. “Type 1 Piliated Uropathogenic Escherichia Coli Hijack the Host Immune Response by Binding to CD14.” ELife. eLife Sciences Publications, 2022. https://doi.org/10.7554/eLife.78995.
K. Tomasek, A. F. Leithner, I. Glatzová, M. S. Lukesch, C. C. Guet, and M. K. Sixt, “Type 1 piliated uropathogenic Escherichia coli hijack the host immune response by binding to CD14,” eLife, vol. 11. eLife Sciences Publications, 2022.
Tomasek K, Leithner AF, Glatzová I, Lukesch MS, Guet CC, Sixt MK. 2022. Type 1 piliated uropathogenic Escherichia coli hijack the host immune response by binding to CD14. eLife. 11, e78995.
Tomasek, Kathrin, et al. “Type 1 Piliated Uropathogenic Escherichia Coli Hijack the Host Immune Response by Binding to CD14.” ELife, vol. 11, e78995, eLife Sciences Publications, 2022, doi:10.7554/eLife.78995.
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