Flagella, Type I Fimbriae and Curli of Uropathogenic Promote the Release of Proinflammatory Cytokines in a Coculture System.

Background: Urinary tract infections (UTIs) are a public health problem in Mexico, and uropathogenic (UPEC) is one of the main etiological agents. Flagella, type I fimbriae, and curli promote the ability of these bacteria to successfully colonize its host.

Aim: This study aimed to determine whether flagella-, type I fimbriae-, and curli-expressing UPEC induces the release of proinflammatory cytokines in an established coculture system.

Methods: The , , and genes by UPEC strain were disrupted by allelic replacement. Flagella, type I fimbriae, and curli were visualized by transmission electron microscopy (TEM). HTB-5 (upper chamber) and HMC-1 (lower chamber) cells cocultured in Transwell plates were infected with these UPEC strains and purified proteins. There was adherence to HTB-5 cells treated with different UPEC strains and they were quantified as colony-forming units (CFU)/mL.

Results: High concentrations of IL-6 and IL-8 were induced by the FimH and FliC proteins; however, these cytokines were detected in low concentrations in presence of CsgA. Compared with UPEC CFT073, CFT073Δ, CFT073ΔΔ, and CFT073ΔΔ strains significantly reduced the adherence to HTB-5 cells.

Conclusion: The FimH and FliC proteins are involved in IL-6 and IL-8 release in a coculture model of HTB-5 and HMC-1 cells.