The in vitro effects on NF-κB augmentation has been reported to be dependent on lactobacilli viability, since after heat-killing they only had a marginal effect on NF-κB activation in co-stimulation experiments with E. coli. This supports modulation of NF-κB as a potential probiotic mechanism. The ability of probiotic lactobacilli to interfere with UPEC colonization in the vagina, and thereby the pathogens’ ascension into the bladder, could therefore involve immunomodulatory activity,

specifically via NF-κB activation. Conclusions The main cause of UTI is ascending E. coli that colonizes the vagina, urethra then bladder. To remove unwanted pathogens, the urothelial cells of the mucosa carry Galunisertib molecular weight specific receptors, such as TLR4 that can recognize the most common Gram-negative species. Once these receptors bind the cognate bacterial ligand, the epithelial cells respond by producing a range of compounds including cytokines that are strongly regulated by the NF-κB transcription factor. The present in vitro study showed that this immune activation could be amplified by probiotic L. rhamnosus GR-1. Moreover, augmentation of NF-κB was accompanied by an increase in inflammatory TNF expression. The important recognition molecule TLR4 was found to be up-regulated by L. rhamnosus GR-1 on both mRNA and protein level in cells concomitantly challenged with E. coli.

Moreover, the blocking agonist binding to TLR4 completely inhibited the augmentation of NF-κB by L. rhamnosus GR-1. Due to the importance IKBKE of TLR4 in the process of pathogen clearance we suggest that this represents selleck a pathway in which probiotic immunomodulatory lactobacilli work to increase immunity and prevent infections. Methods Cell culture The T24 human bladder carcinoma cell line (ATCC HTB-4) was cultured in RPMI 1640 (Hyclone) supplemented with 2.05 mM of L-glutamine and 10%

fetal bovine serum (FBS; Hyclone) at 37°C with 5% CO2 in a humidified environment. Bacterial strains and growth conditions L. rhamnosus GR-1 (urethral isolate) and GG (intestinal isolate) were cultured on de Man Rogosa Sharp (MRS) agar (Difco) anaerobically using anaerobic packs (BD) at 37°C for 24 h under static condition. For cell culture challenge, lactobacilli were grown from a 1% inoculum in MRS broth for 24 h followed by washing and resuspending in the original volume with phosphate buffered saline (PBS; pH 7.4). Uropathogenic E. coli GR12 was grown in Luria-Bertani (LB) medium (Difco) at 37°C and constant shaking. Heat-killed bacteria were prepared by washing cultures in PBS and heating at 70°C for 1 h followed by plating 100 μl on the respective growth medium (MRS or LB) to confirm loss of viability. Heat-killed L. rhamnosus GR-1 and E. coli were stored at -20°C until used for cell challenge.