Project description:Flagellins from commensal bacteria can be weak Toll-like receptor (TLR)5 agonists despite high affinity binding to TLR5, ligands we termed “silent flagellins”. To determine if silent flagellins are detectable in the human gut, endogenous flagellins produced by the microbiota were isolated from stool obtained from a healthy adult female donor. TLR5 was used as bait to enrich for silent flagellins and TLR5-bound flagellins were identified by searching peptides against a custom flagellin database built from metagenome sequences.
Project description:Background:
- Some bacteria found in the large and small intestines help keep people healthy and aid digestion. They may also affect a person s risk of developing cancer. Researchers want to study the relationship between intestinal bacteria and breast cancer risk factors. They can do this by looking at stool and urine samples from postmenopausal women.
Objectives:
- To study intestinal bacteria and its relationship to urine-based markers of breast cancer risk in women.
Eligibility:
- Women between 55 and 69 years of age with a recent mammogram that showed no signs of cancer.
Design:
* Participants will be screened with a medical history and basic health questionnaire.
* At home, participants will complete questionnaires about cancer risk factors and food consumption.
* Participants will also collect urine and stool samples. They will send the samples to the designated labs for study.
* No treatment will be provided as part of this protocol.
Project description:Purpose The role of intestinal flora in carcinogenesis and chemotherapy efficacy has been increasingly studied; however, comparisons between oral and intestinal flora remain limited. This study aimed to identify the microbial changes in urothelial carcinoma (UC) by analyzing oral saliva and stool samples from healthy individuals and patients. We also examined the association between microbial composition and immune checkpoint inhibitor (ICI) response. Methods A total of 20 healthy individuals and 38 patients with UC were analyzed. Among them, 27 patients with UC underwent ICI treatment. Oral saliva and stool samples were analyzed for 16S rRNA sequences to assess bacterial composition. Operational taxonomic units were generated, and phylogenetic analysis was performed using the 16S Metagenomics app whithin the Illumina BaseSpace Sequence Hub. Results Patients with UC showed higher Veillonellaceae and Prevotellaceae levels in saliva and stool, with lower levels of these bacteria associated with more prolonged overall survival and progression-free survival, particularly Veillonellaceae in stool. A higher neutrophil-to-lymphocyte ratio correlated with increased levels of these bacteria. Conclusion Veillonellaceae and Prevotellaceae are potential microbial biomarkers of survival outcomes and ICI efficacy in patients with UC. Non-invasive oral microbial sampling may facilitate personalized cancer treatment strategies.
Project description:Some commensal bacteria stimulate the immune system but do not present specific antigenicity. Such adjuvant effects have been reported for the bacterial species Lactobacillus plantarum. To study in vivo human responses to L. plantarum, a randomised double-blind placebo-controlled cross-over study was performed. Healthy adults were provided preparations of living and heat-killed L. plantarum bacteria, biopsies were taken from the intestinal mucosa and altered transcriptional profiles were analysed. Transcriptional profiles of human epithelia displayed striking differences upon exposure to living L. plantarum bacteria harvested at different growth phases. Modulation of NF-κB-dependent pathways was central among the major altered cellular responses. This unique in vivo study shows which cellular pathways are associated with the induction of immune tolerance in mucosal tissues towards common adjuvanticity possessing lactobacilli. Keywords: mucosal response of healthy adult humans to lactic acid bacteria
Project description:Probiotic bacteria, specific representatives of bacterial species that are a common part of the human microbiota, are proposed to deliver health benefits to the consumer by modulation of intestinal function via largely unknown molecular mechanisms. To explore in vivo mucosal responses of healthy adults to probiotics, we obtained transcriptomes in an intervention study following a double-blind placebo-controlled cross-over design. In the mucosa of the proximal small intestine of healthy volunteers, probiotic strains from the species Lactobacillus acidophilus, L. casei and L. rhamnosus each induced differential gene regulatory networks and pathways in the human mucosa. Comprehensive analyses revealed that these transcriptional networks regulate major basal mucosal processes, and uncovered remarkable similarity to response profiles obtained for specific bioactive molecules and drugs. This study elucidates how intestinal mucosa of healthy humans perceive different probiotics and provides avenues for rationally designed tests of clinical applications. Keywords: mucosal response of healthy adult humans to lactic acid bacteria