TopoClub 2025 6ème journée de rencontre

Validation of Corynebacterium glutamicum as a surrogate for the discovery of new anti-mycobacterial compounds through the study of a well-established antibacterial target: DNA gyrase

Non programmé

20m

salle Dussane (ENS Paris)

Orateur

Yaelle WORMSER (Unité des Mécanismes du Cycle Cellulaire Bactérien, Département de Biologie Structurale & Chimie, Département de Microbiologie, Institut Pasteur, CNRS UMR 3528, Université Paris Cité, Paris, France)

Description

Despite global efforts to combat tuberculosis (TB), the latest WHO report shows a total of 1.3 million people who died from TB, including 167 000 people with HIV. TB is the leading cause of death among HIV-infected patients, and the first leading infectious killer. Worldwide, multridrug-resistant TB (MDR- TB) is a major a public health problem and security threat. In order to eradicate TB, the main challenges include the understanding of the biology of Mycobacterium tuberculosis (Mtb), the discovery and validation of new targets, the identification of new inhibitors with novel mechanisms of action (MOA) to treat multi- and extensively drug-resistant TB, as well as the development of new biochemical screens representative of the in vivo microenvironment.

In the lab, our goal is to develop a unified framework for the identification of new anti-tuberculosis drugs, relying on a non-pathogenic model organism, Corynebacterium glutamicum. The latter shares core characteristics with Mtb, such as its complex cell wall, that constitutes an important permeability barrier for antibiotics. We are setting up an in vivo cell-screening approach to test and indentify new actives drugs directly on the bacteria/our model organism. We will use the DNA gyrase, a validated target for anti-TB treatment, as a proof of principle for this assay (Petrella. S. 2019). The DNA gyrase is a type IIA topoisomerase capable of modulating DNA topology, essential for Mtb survival, thus making it a particularly interesting target for antibiotics. Our preliminary work shows that anti-gyrase inhibitors against Mtb are also active on the C. glutamicum gyrase. Indeed, these molecules confer a highly distinctive morphology on C. glutamicum that can be analysed using our cell-based assay. We are characterizing the mode of action of these inhibitors at the atomic level using cryo-electron microscopy in order to relate the detailed interactions between the DNA gyrase and the drugs to the morphologies identified. In parallel, we are also using C. glutamicum to identify the target(s) of compounds that have a confirmed activity against Mtb and that lead to a strong morphological readout in C. glutamicum.
I will present our work in progress and outline the detailed workflow of the project.