Toll-like receptors (TLRs) are key components of the innate immune system that trigger antimicrobial host defense responses. The aim of the present study was to analyze the effects of probiotic Escherichia coli Nissle strain 1917 in experimental colitis induced in TLR-2 and TLR-4 knockout mice. Colitis was induced in wild-type (wt), TLR-2 knockout, and TLR-4 knockout mice via administration of 5% dextran sodium sulfate (DSS). Mice were treated with either 0.9% NaCl or 10 7 E. coli Nissle 1917 twice daily, followed by the determination of disease activity, mucosal damage, and cytokine secretion. wt and TLR-2 knockout mice exposed to DSS developed acute colitis, whereas TLR-4 knockout mice developed significantly less inflammation. In wt mice, but not TLR-2 or TLR-4 knockout mice, E. coli Nissle 1917 ameliorated colitis and decreased proinflammatory cytokine secretion. In TLR-2 knockout mice a selective reduction of gamma interferon secretion was observed after E. coli Nissle 1917 treatment. In TLR-4 knockout mice, cytokine secretion was almost undetectable and not modulated by E. coli Nissle 1917, indicating that TLR-4 knockout mice do not develop colitis similar to the wt mice. Coculture of E. coli Nissle 1917 and human T cells increased TLR-2 and TLR-4 protein expression in T cells and increased NF-B activity via TLR-2 and TLR-4. In conclusion, our data provide evidence that E. coli Nissle 1917 ameliorates experimental induced colitis in mice via TLR-2-and TLR-4-dependent pathways.

Galectins have recently emerged as central regulators of the immune system. We have previously demonstrated that carbohydrate-dependent binding of galectin-2 induces apoptosis in activated T cells. Here, we investigate the potential therapeutic effect of galectin-2 in experimental colitis. Galectin-2 expression and its binding profile were determined by immunohistochemistry. Acute and chronic colitis was induced by dextran sodium sulfate administration and in a T-cell transfer colitis model. Apoptosis was assessed by TdT-mediated dUTP-biotin nick-end labeling, and cytokine secretion was determined by cytometric bead array. We show that galectin-2 was constitutively expressed mainly in the epithelial compartment of the mouse intestine and bind to lamina propria mononuclear cells. During colitis, galectin-2 expression was reduced, but could be restored to normal levels by immunosuppressive treatment. Galectin-2 treatment induced apoptosis of mucosal T cells and thus ameliorated acute and chronic dextran-sodium-sulfate-induced colitis and in a T-helper-cell 1-driven model of antigen-specific transfer colitis. Furthermore, the pro-inflammatory cytokine release was inhibited by galectin-2 treatment. In preliminary toxicity studies, galectin-2 was well tolerated. Our study provides evidence that galectin-2 induces apoptosis in vivo and ameliorates acute and chronic murine colitis. Furthermore, galectin-2 has no significant toxicity over a broad dose range, suggesting that it may serve as a new therapeutic agent in the treatment of inflammatory bowel disease.

Human gammadelta T cells play a vital role in the innate and adaptive immune response to microbial antigens by acting as antigen-presenting cells while at the same time being capable of directly activating CD4(+) T cells. Pathogenic microbes or loss of tolerance toward the host's own microflora trigger many diseases including inflammatory bowel diseases. We previously demonstrated that Escherichia coli Nissle 1917 directly interacts with the adaptive immune system by regulating central T cell functions. Here we aimed to investigate whether E. coli Nissle regulates gammadelta T cell function, thereby linking the innate and adaptive immune system. In our study, we demonstrate that, in contrast to the other probiotic strains tested, E. coli Nissle increased activation, cell cycling and expansion of gammadelta, but not alphabeta T cells. In gammadelta T cells, E. coli Nissle reduced tumor necrosis factor-alpha secretion but increased IL-6 and CXCL8 release. However, after activation, only E. coli Nissle induced gammadelta T cell apoptosis, mediated via Toll-like receptor-2 by caspase- and FasLigand-dependent pathways. gammadelta T cells play an important role in the recognition of microbial antigens and the perpetuation of inflammatory processes. The demonstration that E. coli Nissle, but not the other bacteria tested, profoundly regulate gammadelta T cell function contributes to explaining the biological function of this probiotic strain in inflammatory diseases and provides us with a better understanding of the role of gammadelta T cells.

BackgroundProspective, observational studies that enroll large numbers of patients with few exclusion criteria may better reflect actual ongoing clinical experience than randomized clinical trials. Our purpose was to obtain efficacy and safety information from a cohort of subjects exposed to latanoprost/timolol fixed combination (FC) for ≥18 months using a prospective, observational design.MethodsIn all, 577 office-based ophthalmologists in Germany switched 2339 patients with glaucoma or ocular hypertension to latanoprost/timolol FC for medical reasons. Follow-up visits were scheduled for every 6 months over 24 months; physicians followed usual care routines. Intraocular pressure (IOP), visual field status, optic nerve head findings, and adverse events were recorded. Efficacy parameters were evaluated for the per protocol (PP) population; the safety population included subjects receiving ≥1 drop of FC. Physicians rated efficacy, tolerability, and subject compliance at month 24.ResultsOf the 2339 subjects switched to latanoprost/timolol FC (safety population), the primary reasons for switching were inadequate IOP reduction (78.2%) and desire to simplify treatment with once-daily dosing (29.4%; multiple reasons possible). In all, 1317 (56.3%) subjects completed the study, and 1028 (44.0%) were included in the PP population. Most discontinuations were due to loss to follow-up. Change in mean IOP from baseline to month 6 was -4.0 ± 4.31 mmHg, a reduction that was maintained throughout (P < 0.05 for change at all time points). By investigator assessments, optic disc parameters and visual field were stable over 24 months, and there was no relationship between IOP reduction over 24 months and development of a visual field defect. More than 90% of physicians rated latanoprost/timolol FC as "very good" or "good" for efficacy (PP population), tolerability, and compliance. The FC was safe and well tolerated. No change in iris color was reported by most subjects (83.1%) at month 24.ConclusionsOver 24 months, latanoprost/timolol FC effectively lowers IOP levels and is well tolerated in patients with glaucoma or ocular hypertension who change from their previous ocular hypotensive therapy for medical reasons. Investigator assessments found optic disc parameters and visual field to be stable throughout 24 months of follow-up.

Our study provides evidence that by promoting wound healing and regulating T cell function, EN, AM, and PN potently interact with the intestinal barrier and immune system, thus justifying its use in diseases accompanied by impaired mucosal barrier function.