Error bars represent the standard errors of the means. Bars labeled with an asterisk significantly differ from the control (p-values < 0.05). Figure 2 NF-κB activation and expression of cytokines in bladder cells after stimulation with L. rhamnosus GR-1. Viable (V) or heat-killed (HK) L. rhamnosus GR-1 at a concentration of 2 × 107 cfu/ml were used to challenge bladder cells for 24 h. (A) Relative NF-κB activation (n = 4) and (B) TNF, IL-6, and CXCL8 levels (n = 3) were measured using luciferase NCT-501 clinical trial assay and ELISA, respectively. Error bars represent the standard errors of the means. Bars labeled with
an asterisk significantly differ from the control (p-values < 0.05). Lactobacilli do not normally come into contact with bladder cells, therefore we determined the cytotoxicity caused by lactobacilli exposure. However, we did not observe
decreased epithelial cell viability compared to resting cells, as determined using Blasticidin S propidium iodide stained cells and flow cytometry (data not shown). Viable lactobacilli potentiated NF-κB activation and cytokine response in E. coli-stimulated cells Bladder cells were relatively indifferent mTOR inhibitor towards stimulation with both viable and heat-killed lactobacilli, whereas the cells responded appropriately towards stimulation with E. coli, leading to increased NF-κB activation and release of inflammatory mediators. Co-stimulation with viable lactobacilli and heat-killed E. coli did however result in increased NF-κB activation compared to cells challenged with E. coli alone
(Figure Lck 3A). This NF-κB induction was beyond an eventual additive effect, representing a synergistic action on NF-κB activation. On the protein level, co-stimulation influenced the release of all studied inflammatory mediators. The TNF release was increased by a factor of two to three, while IL-6 and CXCL8 levels were reduced compared to those found during E. coli challenge alone (Figure 3B). Figure 3 NF-κB activation and cytokine secretion after concomitant stimulation with E. coli and L. rhamnosus GR-1. Bladder cells were challenged for 24 h with heat-killed E. coli alone or together with viable (V) or heat-killed (HK) L. rhamnosus GR-1. (A) Relative NF-κB activation (n = 4). (B) TNF, IL-6 and CXCL8 levels (n = 3) were measured. Bars labeled “”a”" are significantly different from control and “”b”" significantly different from cells stimulated with E. coli (p-values < 0.05). NF-κB activation was significantly reduced when bladder cells were exposed to heat-stable cell wall components of lactobacilli (Figure 3A), indicating that potentiation was mediated by compound(s) released during the growth of L. rhamnosus GR-1. L. rhamnosus GR-1 and GG augmented NF-κB to different levels Lactobacillus rhamnosus GG, a well-studied immunomodulatory strain used for gastrointestinal disorders, was chosen to compare NF-κB augmenting abilities. Both L. rhamnosus GR-1 and GG had the ability to potentiate E. coli induced NF-κB activation (Figure 4). While L.