Project description:RNAseq was carried out to compare the gene expression profiles of the worms grown with individual bacteria to understand the bacterial effect
Project description:Bacteria-based cancer immunotherapy, dated back to Coley’s toxins (inactivated bacteria) in 1893, has recently regained substantial attentions, usually by using attenuated bacteria to transform immune-silent “cold” tumors into immune-inflamed “hot” ones. However, while inactivated bacteria showed limited antitumor efficacy, attenuated live bacteria often possessed significant safety risks. Herein, by biomineralizing growth of manganese dioxide on the surface of paraformaldehyde-fixed gram-negative Salmonella typhimurium (S. typhimurium), we obtained MnO2-coated fixed S. typhimurium (M@F.S), which showed potent immune-stimulating effects via activating multiple pathways including Toll-like receptors (TLRs), cyclic GMP-AMP Synthase (cGAS)-stimulator of interferon genes (STING) and nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs). Single intratumoral administration of M@F.S at safe doses resulted in surprisingly strong efficacies in suppressing various types of mouse tumor models and a rabbit cancer model, and the cured mice and rabbits gained immune memory to reject re-challenged tumors. An abscopal antitumor effect was also observed, suggesting systemic antitumor immunity triggered by local injection of M@F.S. The antitumor mechanisms of M@F.S were preliminarily demonstrated to be innate immune activation initiated by multiple signaling pathways, followed by subsequent activation of tumor-specific immune responses, together with the modulation of immunosuppressive tumor microenvironment. We further demonstrated the efficacy of biomineralized bacteria in inhibiting an orthotopic breast tumor model established on tree shrews, an alternative animal model to primates with better clinical relevance. Such oncolytic biomineralized bacteria could be a potent yet safe immunotherapeutic agent for treatment of various solid tumors.
Project description:The aim of this experiment was to determine if the development of resistance to antibiotics can be driven by the concentration and speciation of Cu. Experimental setup was designed to investigate two hypotheses for which two strains of Gram- bacteria have been selected: - Do TE enhance AR in resistant bacteria? Resistant strain: Bioluminescent Pseudomonas aeruginosa PAO1 (Xen41, Tetracycline resistant) - Do TE induce AR in sensitive bacteria? Sensitive strain: Pseudomonas aeruginosa PAO1 (Wild Type)
Project description:Our microbiota affects numerous processes involved in development, health, and the response to chemotherapeutic drugs. Tamoxifen is a selective estrogen receptor (ER) modulator that is used to treat ER positive breast cancer, but that at high doses kills both ER positive and ER-negative breast cancer cells. We recapitulate this off-target effect in Caenorhabditis elegans, which does not have an ER ortholog. We find that different bacteria dramatically modulate tamoxifen toxicity in C. elegans, with a three-order of magnitude difference between animals fed Escherichia coli, Comamonas aquatica, and Bacillus subtilis. Remarkably, host fatty acid (FA) biosynthesis mitigates tamoxifen toxicity, and different bacteria provide the animal with different FAs, resulting in distinct FA profiles. Surprisingly these bacteria modulate tamoxifen toxicity by different death mechanisms, some of which are modulated by FA supplementation and others by antioxidants. Together, this work reveals a complex interplay between bacteria, FA metabolism and tamoxifen toxicity that may provide a blueprint for similar studies in more complex mammals.
Project description:Type 1 diabetes (T1D) is a chronic autoimmune disease that results from destruction of pancreatic β-cells. T1D subjects were recently shown to harbor distinct intestinal microbiome profiles. Based on these findings, the role of gut bacteria in T1D is being intensively investigated. The mechanism connecting intestinal microbial homeostasis with the development of T1D is unknown. Specific gut bacteria such as Bacteroides dorei (BD) and Ruminococcus gnavus (RG) show markedly increased abundance prior to the development of autoimmunity. One hypothesis is that these bacteria might traverse the damaged gut barrier, and their constituents elicit a response from human islets that causes metabolic abnormalities and inflammation. We have tested this hypothesis by exposing human islets to BD and RG in vitro, after which RNA-Seq analysis was performed. The bacteria altered expression of many islet genes. The commonly upregulated genes by these bacteria were cytokines, chemokines and enzymes, suggesting a significant effect of gut bacteria on islet antimicrobial and biosynthetic pathways. Additionally, each bacteria displayed a unique set of differentially expressed genes (DEGs). Ingenuity pathway analysis of DEGs revealed that top activated pathways and diseases included TREM1 Signaling and Inflammatory Response, illustrating the ability of bacteria to induce islet inflammation. The increased levels of selected factors were confirmed using immunoblotting and ELISA methods. Our data demonstrate that islets produce a complex anti-bacterial response. The response includes both symbiotic and pathogenic aspects. Both oxidative damage and leukocyte recruitment factors were prominent, which could induce beta cell damage and subsequent autoimmunity.
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.