Project description:Polysialic acid (polySia) is a linear polymer of α2,8-linked sialic acid residues that is of fundamental biological interest due to its pivotal roles in the regulation of the nervous, immune, and reproductive systems in healthy human adults. PolySia is also dysregulated in several chronic diseases, including cancers and mental health disorders. However, the mechanisms underpinning polySia biology in health and disease remain largely unknown, in part due to the lack of tools with which to study the glycan. The polySia-specific hydrolase, endoneuraminidase NF (EndoN), and the catalytically inactive polySia lectin EndoNDM, have been extensively used for studying polySia. However, EndoN is heat stable and remains associated with cells after washing. When studying polySia in systems with multiple polysialylated species, the residual EndoN that cannot be removed confounds data interpretation. We developed a strategy for site-specific immobilization of EndoN and EndoNDM on streptavidin-coated magnetic or agarose beads. We showed that immobilizing EndoN improves enzyme usefulness by allowing for effective removal of the enzyme from samples, while retaining hydrolase activity. Additionally, immobilization of EndoNDM allowed for the enrichment of polysialylated proteins from complex mixtures for their identification via mass spectrometry. We identified QSOX2 as a novel polysialylated protein secreted from MCF-7 cells. This method of site-specific immobilization can be utilized for other enzymes and lectins to yield insight into glycobiology.
Project description:Sulforaphane is a naturally occurring, potent antioxidant and anti-inflammatory compound, found in cruciferous plants such as broccoli. Recently there have been a large number of clinical trials assessing broccoli sprout extracts as sulforaphane-based therapies for conditions including fibrosis, cancer and preeclampsia. As sulforaphane is orally administered, there is also the potential for impact on the gut microbiome. Here, we have determined the effect of sulforaphane on the growth of 43 common human gastrointestinal bacterial commensals and pathogens, which represented the four main phyla found in the human gastrointestinal microbiome. The pathogenic Escherichia coli strain ECE2348/69 showed the most significant increases in growth in the presence of sulforaphane compared to control conditions. Proteomic analysis of this isolate showed that sulforaphane increased anaerobic respiration, whilst metabolomic profiling identified differentially produced metabolites involved in amino acid biosynthesis and known to decrease inflammation in human cells. Therefore, sulforaphane can increase growth of specific gastrointestinal bacterial isolates, correlating with increased production of anti-inflammatory metabolites, that may provide a novel mechanism for modulating inflammatory states in patients.
Project description:Coxiella burnetii is a Gram-negative intracellular pathogen that causes the debilitating disease Q fever, which affects both animals and humans. The only available vaccine, Q-Vax, is effective but has a high risk of severe adverse reactions, limiting its use as a countermeasure to contain outbreaks. Therefore, it is essential to identify new drug targets to treat this infection. Macrophage infectivity potentiator (Mip) proteins catalyze the folding of proline-containing proteins through their peptidyl prolyl cis-trans isomerase (PPIase) activity and have been shown to play an important role in the virulence of several pathogenic bacteria but to date its role in C. burnetii pathogenesis has not been investigated. This study demonstrates that CbMip is likely to be an essential protein in C. burnetii. Pipecolic acid derived compounds, SF235 and AN296 demonstrate inhibitory activities against CbMip and these compounds were found to significantly inhibit intracellular replication of C. burnetii in both HeLa and THP-1 cells. Furthermore, SF235 and AN296 were also found to exhibit antibiotic properties against both the virulent (Phase I) and avirulent (Phase II) forms of C. burnetii Nine Mile Strain RSA439 in axenic culture with comparative proteomic demonstrating selective alterations in response to these agents. This study also showed that exposure of C. burnetii to Mip inhibitors resulted in increased sensitivity to oxidative stress. Furthermore, compounds SF235 and AN296 demonstrated protective activity in vivo and significantly improved the survival of Galleria mellonella infected with C. burnetii. These results suggest that unlike in other bacteria, Mip in C. burnetii is required for growth and replication and that inhibitors against CbMip offer potential as novel therapeutics against C. burnetii.