Several TLR ligands of bacterial origin induce innate immune responses. Although FimH, the adhesin portion of type 1 fimbria, plays an important role in the pathogenicity of some gram-negative bacteria, its ability to stimulate the innate immune system via TLR signaling remains unclear. In this study we report that FimH induces potent innate responses in a MyD88-dependent fashion. The FimH-induced innate activity was restricted to cells expressing TLR4. In addition, FimH was able to bind directly to TLR4. More importantly, cells unresponsive to LPS were responsive to FimH and the presence or absence of MD-2 and CD14 had no effect on FimH activity. Our data suggest that TLR4 is a functional receptor for the adhesin portion of bacterial type 1 fimbria.
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http://dx.doi.org/10.4049/jimmunol.181.10.6702 | DOI Listing |
PLoS One
January 2025
Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America.
Urinary tract infections (UTIs) are among the most common bacterial infections of both dogs and humans, with most caused by uropathogenic Escherichia coli (UPEC). Recurrent UPEC infections are a major concern in the treatment and management of UTIs in both species. In humans, the ability of UPECs to form intracellular bacterial communities (IBCs) within urothelial cells has been implicated in recurrent UTIs.
View Article and Find Full Text PDFbioRxiv
December 2024
Department of Biochemistry, University of Washington, Seattle, WA.
A critical step in infections is the attachment of many microorganisms to host cells using lectins that bind surface glycans, making lectins promising antimicrobial targets. Upon binding mannosylated glycans, FimH, the most studied lectin adhesin of type 1 fimbriae in , undergoes an allosteric transition from an inactive to an active conformation that can act as a catch-bond. Monoclonal antibodies that alter FimH glycan binding in various ways are available, but the mechanisms of these antibodies remain unclear.
View Article and Find Full Text PDFbioRxiv
December 2024
Department of Molecular Microbiology, Washington University in St Louis, St Louis, MO, U.S.A.
As antimicrobial resistance increases, urinary tract infections (UTIs) are expected to pose an increased burden in morbidity and expense on the healthcare system, increasing the need for alternative antibiotic-sparing treatments. Most UTIs are caused by uropathogenic (UPEC), while causes a significant portion of non-UPEC UTIs. Both bacteria express type 1 pili tipped with the mannose-binding FimH adhesin critical for UTI pathogenesis.
View Article and Find Full Text PDFBMC Microbiol
November 2024
Department of Microbiology and Immunology, Faculty of Pharmacy, Tanta University, Tanta, Egypt.
Background And Aim: Pathogenic Escherichia coli is a known harmful microorganism that takes advantage of favorable conditions to cause various infections in healthcare settings, such as bloodstream infections related to catheters, as well as infections in the urinary and respiratory tracts. E. coli utilizes biofilm development as a means to enhance its virulence and pathogenicity.
View Article and Find Full Text PDFVarious bacteria are suggested to contribute to colorectal cancer (CRC) development, including pks Escherichia coli, which produces the genotoxin colibactin that induces characteristic mutational signatures in host epithelial cells. However, it remains unclear how the highly unstable colibactin molecule is able to access host epithelial cells to cause harm. Here, using the microbiota-dependent ZEB2-transgenic mouse model of invasive CRC, we demonstrate that the oncogenic potential of pks E.
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