The Myco3V TBRU scientists endeavor to provide the first descriptions of cell envelope variation among Mycobacterium tuberculosis (Mtb) isolates from patients with tuberculosis and identify key determinants of its virulence and barrier to drug action that could inform the development of better diagnostics and therapeutics.

The TBRU Myco3V team has created new genetic and metabolomic tools to comprehensively dissect and analyze the metabolite and lipid components of the entire Mtb envelope of a large number of clinical Mtb isolates. We will accomplish this goal through three projects supported by five cores.

Rachel Meade & Clare Smith

Project 1: Study of M. tuberculosis under human host selection to identify virulence and barrier lipids

From a biological perspective, Mtb’s lipid envelope forms the primary interface with the host and is, therefore, a direct and ongoing biochemical target of evolutionary selection. Through this project, first we aim to reveal the previously undescribed chemical diversity and lipid products that have arisen as a consequence of host- and drug-driven selection pressure. Then, armed with this knowledge we will use CRISPRi interference strategies to establish causal linkages between newly discovered lipids and genes of unknown function, and test them in mice to reveal specific roles in Mtb virulence.

This project emerges from collaborative work involving expertise in lipid profiling (Moody lab, Brigham and Women's Hospital and Rhee lab, Cornell Medicine), CRISPRi technology (Rock lab, Rockefeller University), collaborative cross mice (Smith lab, Duke University), and chemical syntheses (Minnaard lab, Groningen University).

Project 2: Metabolic determinants of barrier function in rifampin-sensitive and -resistant Mtb

The overarching goal of this project is to elucidate specific cell envelope structure-activity relationships mediating barrier function. A key and quite literal barrier to safer and simpler drugs and treatments for TB is its highly unusual cell envelope. Improved knowledge of the barrier function of the Mtb envelope thus represents a potential blueprint to developing better safer drugs. Unlike most bacteria, the Mycobacterium tuberculosis (Mtb) envelope consists in a unique multilayered structure whose physico-chemical properties are widely believed to mediate an intrinsic mechanism of antibiotic resistance. This project specifically focuses on Mtb barrier function through the therapeutic lens of the frontline TB drug rifampicin.

This project is a collaboration among Kyu Rhee (Weill Cornell Medicine) Valerie Mizrahi (University of Cape Town), Jeremy Rock (Rockefeller University) and D. Branch Moody (Brigham and Women's Hospital.

A Black Color Graph With Moldings
A Group of People Testing on a Machine

Project 3: Metabolic biomarkers of TB disease, treatment response and infectiousness

Sputum-based tests are a mainstay of modern tuberculosis (TB) diagnostics that have historically proven invaluable. However, their utility has proven variable across clinical settings and patient populations where disease prevalence and mortality are high, including diagnosing TB in children and HIV co-infected patients. Existing diagnostics have further focused chiefly on disease detection. Yet, control of the TB pandemic ultimately also requires the ability to monitor treatment efficacy and disease transmissibility. Project 3 seeks to address these unmet diagnostic needs by developing a new panel of metabolite-based biomarkers present in human serum and urine, which are readily obtained from nearly all subjects.

Project 3 emerges from the collaboration among Professor Robin Wood (Desmond Tutu Health Foundation), Digby Warner (University of Cape Town), Kyu Rhee and D. Branch Moody.