Principal Investigator (PI)
The Foundation is providing £178,222 in support.
Kyla Johnson
We are performing a large-scale, multi-phase compound screen in drug tolerant Mtb in close collaboration with the Tres Cantos Open Lab Foundation (TCOLF) and GSK.
To date, we have screened GSK’s library of 75,000 chemically diverse compounds and they have generously provided us with additional synthesis of promising preliminary drug candidates for further characterization and mechanistic studies.
Compound screens were optimized and conducted on site at Tres Cantos using GSK’s facilities, equipment, and high-throughput assay platforms.
We are also in close collaboration with personnel at Tres Cantos whose scientific and technical expertise have been instrumental in making these innovative but technically challenging large-scale experiments feasible.
Tuberculosis (TB), a leading cause of death due to infectious disease is notoriously difficult to treat, at least partially due to the emergence of drug-tolerant populations of Mycobacterium tuberculosis (Mtb), the causative agent of TB.
Drug tolerance is a transient, phenotypic state induced by stressors such as antibiotic treatment. The transient nature of drug tolerant populations provides a major barrier to identifying effective drugs against this state. Our lab identified phase-variation in the glycerol kinase gene (glpK) as a major determinant of drug tolerance in Mtb, acting through reversible mutations in a homopolymeric region.
Homopolymeric glpK mutants are found in clinical samples, accumulate in drug-treated mice, and are associated with poor clinical outcomes. Identifying novel drugs and vulnerable drug targets against these clinically significant glpK mutants could transform TB treatment by providing a pathway to effectively kill drug tolerant Mtb.
We generated an H37Rv DglpK strain which has a permanent drug tolerant phenotype, constitutively express lux, and mimics classic phenotypes of drug tolerant Mtb.
We discovered unique genetic liabilities in the DglpK strain using RNA-seq and Tn-seq showing that Mtb glpK mutants have unique drug targets compared to WT strains and will be differentially susceptible to a novel set of antimycobacterial drugs.
Aim 1 will identify preliminary drug candidates differentially active against DglpK strain by performing a focused, multi-phased whole-cell compound screen of 75,000 chemically diverse compounds from GlaxoSmithKline in collaboration with the Tres Cantos Open Lab Foundation, utilizing both lux-expressing DglpK strains and a TET-inducible glpK expression system.
Aim 2 will investigate genes and pathways targeted by promising preliminary drug candidates by raising resistant mutants in the DglpK strain and using CRISPRi to validate target-specific activity. Identifying potentially new classes of drug candidates targeting drug tolerant Mtb could lead to more effective and rapid TB treatments.