Principal Investigator (PI)
The Foundation is providing £207,100 in support.
Lauren Butler, Yuming Cai
GSK´s Global Health team focuses on infectious diseases which disproportionately impact the world’s most vulnerable populations.
In this project GSKGH will contribute their world-leading global health R&D expertise, the intramacrophage screening platform and hit compounds with observed intramacrophage antibacterial activity from the GSK diversity set.
Once the TraDIS-Xpress library has been created in Salmonella Typhimurium ST313, the library will be shipped to Tres Cantos and be exposed to GSKGH’s intracellular screening platform with selected compounds identified from the initial efficacy screen.
GSKGH’s expertise in macrophage cell culture and intracellular Salmonella research will be essential to replicate the culture conditions necessary to test drug activity.
Once experiments are completed, DNA from the mutant libraries will be extracted and sent back to QI for sequencing and data analysis.
Drug targets will be identified by high throughput parallel analysis software developed at QI, and these targets will be discussed with experts at GSKGH to determine the best follow-up action.
Salmonella spp and particularly fluoroquinolone resistant strains have been identified by the WHO as a high priority pathogen (1) causing a serious threat to public health. Infection caused by non-typhoidal Salmonella in sub-Saharan Africa is already a major problem with no available vaccine. Infections in this context are mainly caused by an epidemic clone of Salmonella Typhimurium, ‘ST313’. Treatment is complicated by development of antibiotic resistance and the intramacrophage Salmonella life cycle limiting efficacy of traditional antibiotics.
There is a pressing need for novel therapies to treat Salmonella infections. This project addresses this challenge using; (i) a high-throughput imaging-based screening platform for intramacrophage antibacterial activity available at GSK Global Health (GSKGH) and (ii) a new massively parallel transposon mutagenesis screen ‘TraDIS-Xpress’ by the Quadram Institute (QI). We will combine these platforms to study hits with specific activity against intracellular bacteria and determine their mechanisms of action and resistance potential.
TraDIS-Xpress is a rapid and high throughput approach to identify bacterial genes involved in response to a stress. The fitness of massive pools of random transposon mutants are compared between stress and control conditions to identify genes under selective pressure. QI has pioneered the inclusion of outward facing promoters in the transposons allowing us to measure impacts of both gene inactivation and altered expression in a single experiment.
In this project we will:
a) access tool compounds and antibacterial molecules with anti-Salmonella activity within macrophages from a unique screen developed by GSKGH.
b) build a new TraDIS-Xpress library in ST313 and use this to identify the essential genes for intra macrophage survival and identify genes mediating susceptibility to a selection of ~10 hit compounds from a).
c) validate predicted mechanisms of action and resistance of promising compounds by creating defined mutants and testing phenotypic outcomes.
The project will deliver biological information to help development of intracellular antibacterials, a series of validated hits to be prioritised for future progression and a new paradigm for intracellular antibacterial screening.