Yi Xu
Texas A&M University-College Station, TX·Microbiology & Immunology
Some bacteria that normally live quietly in the gut can slip into the bloodstream and cause life-threatening infections, and in some cases they also appear to encourage tumors to grow. Streptococcus gallolyticus subsp.
- Fields
Microbiology & Immunology
Biology
Medicine & Clinical Research
- Topics
Streptococcus gallolyticus
Sgg
type VII secretion system
- Grants
- 1 known grant, through Oct 2028
What they work on
- Determine how important the secreted protein EsxA is to Streptococcus gallolyticus virulence, using bacterial mutants together with the cell culture and animal infection models established in the lab.
- Test the hypothesis that EsxA acts as a new ligand for a host cell surface growth factor receptor, and map the signaling events this binding sets off in colonic epithelial cells.
- Define the biological outcomes of EsxA activity on the colon lining, including effects on epithelial homeostasis, cell proliferation, and bacterial movement between cells across the barrier.
- Assess how broadly the proposed type VII secretion-based virulence mechanism applies by comparing EsxA-dependent activities across a panel of Streptococcus gallolyticus strains.
More about the research
gallolyticus (Sgg) is one of these organisms: it is linked to bloodstream infection, infective endocarditis (an infection of the heart's inner lining), and colorectal cancer. Strikingly, about 60% of patients with Sgg bloodstream infection or endocarditis also have colorectal cancer, which suggests that what Sgg does in the intestine is tightly connected to what it does once it reaches the circulation. Despite this clinical importance, the molecular tools Sgg uses to cause disease are largely unknown.
Why it matters
Sgg infections cause serious bloodstream and heart-valve disease and travel together with colorectal cancer in most patients, yet clinicians have little mechanistic understanding of how the bacterium harms people. Pinpointing EsxA and the host receptor it may act on could reveal why this organism promotes tumors and barrier damage, and could eventually point to bacterial targets for preventing or treating these infections.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Wendy S. Garrett
Harvard University, MA·Microbiology & Immunology
Test whether hydrogen sulfide made by Fusobacterium nucleatum, a gas-phase bacterial metabolite, alters colon lining cells and immune cells in the developing tumor environment, using preclinical mouse models of colorectal cancer.
Patricia A Champion
University of Notre Dame, IN·Microbiology & Immunology
Identify how Mycobacterium marinum senses the detergent tyloxapol, combining unbiased genetic screens with hemolysis assays, and test whether tyloxapol suppresses ESX-1 membrane-breaking activity during macrophage infection.
Sabine Ehrt
Weill Medical College of Cornell University, NY·Microbiology & Immunology
Test whether mutations found repeatedly in patient strains in the metabolic enzymes PPGK, PEPCK and LDH change M. tuberculosis disease progression and antibiotic susceptibility, and identify the clinical pressures and interacting mutations that select them.
The school
Texas A&M University-College Station: 23 labs on PI Pages, $1.4B a year on research, 768 research doctorates a year.
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