UKRI FLF renewal: Energy Metabolism and Antibiotic Action in the Tuberculosis Pathogen

Scientific background

Bioenergetic systems give living organisms the energy they need to live and grow. For organisms that grow with air, bioenergetic systems are composed of electron transport chains that take electrons from food molecules and pass them to oxygen, using the released energy to pump protons across a membrane. A different system, ATP synthase, uses these protons to power the addition of phosphate to ADP to make ATP.

ATP then powers the cell. Humans have these systems, but so do bacterial pathogens such as tuberculosis. A number of new drugs against tuberculosis have been recently released that target bioenergetics. A notable example is bedaquiline that inhibits ATP synthase.

A major achievement in the first phase of this fellowship, which is still active, was to set up biophysical methods to measure bioenergetics in living tuberculosis cells and use these methods to understand the mechanism of bedaquiline. In this extension, we will be building on these foundations to make further fundamental discoveries in how tuberculosis energises itself, use these discoveries to understand combinations of antibiotics that target bioenergetics, and just as importantly for this scheme, use the time and space provided by the FLF to keep developing the team members.

Overarching UKRI FLF Renewal aim:

To use our biophysical methods established in the first phase of the FLF project to understand fundamental principles underlying mycobacterial bioenergetics and how those principles apply to bioenergetic-targeting antibiotics used alone and in combination.

Theme 1: Using the biophysical tools developed in the first phase of the FLF to understand more about the fundamental biology of mycobacteria

We have teamed up with Dr Roger Springett to develop and apply methods to measure the state of the mycobacterial electron transport chain in vivo. With this system we discovered that mycobacteria possess an ability to rapidly reroute electrons through their electron transport chain in response to antibiotics. In the renewal, we will explore the underlying molecular mechanism of this rerouting, specifically how 'CydAB' is activated.

We will also build on our findings around the biochemistry of mycobacterial bioenergetics by exploring how mycobacteria generate their complement of oxidative phosphorylation enzymes.

Theme 2 Apply our fundamental findings within mycobacterial bioenergetics to understand the action of approved antimycobacterial compounds

Probably the most important output from the first phase of the FLF project was our proposal for the mechanism of the antitubercular compound bedaquiline, which is currently being written up for publication. In this second phase, we will continue to explore the interactions of compounds that are in active use in the clinic or in late stage clinical trials.

A key part of antituberculosis regimes is the design of effective combinations of antibiotics. The combination of drugs used affects how well they clear an infection: they can work very well together (synergy) or poorly (antagonism). Using what we have found out on the activity of the drugs such as bedaquiline and Q203 acting alone, we will start exploring what happens when compounds are used in combination to explain their synergistic or antagonistic effects. This knowledge should help scientists develop better compounds and regimes in the future.

Theme 3: Develop as responsible researchers

Beyond generating results in the lab, a critical part of the FLF project is that both the appointed FLF (Dr Jamie Blaza) and the scientist recruited on the project (Dr Morwan Osman) use it as an opportunity to develop into responsible and effective scientist-leaders. They will continue to take advantage of mentorship networks and development opportunities to actively address weaknesses and opportunities beyond the scientific research that makes the core of the proposal. This development will set them up for their later careers