Major Facilitator Superfamily transporters as targets for combatting wide-range antibiotic resistance

Multi-resistant tuberculosis is a rising global threat, with approximately 490,000 new cases every year, and with few solutions. Non-tuberculous mycobacterial infections are also on the rise and some of these bacteria are highly drug resistant and difficult to treat. One of the mechanisms of resistance is drug efflux, where the bacteria transport antibiotics out of the cells. The ultimate goal of this project is to fight antimicrobial resistance by the development of a new type of drug, targeting these drug-efflux transporters. One of the transporters have previously been reported to transport tetracycline out of the cells. This causes mycobacteria to be highly resistant against tetracycline. There is also evidence that the same transporter may cause rifampicin resistance, but this needs to be studied further. Through a collaboration with the University of Bergen, three compounds have been identified as potential drug efflux inhibitors, reversing the effect of the tetracycline transporter. The compounds are already approved drugs against other diseases and can therefore be fast tracked through the drug development process if further tests are positive. One of the major goals of this project was solving the 3D structure of a drug-efflux transporter. We have not quite reached this goal, but there are more tactics to explore. We have identified and produced an inactive variant of the transporter. This is more likely to crystallize, as has been observed previously for other transporters, and might be the solution to the challenge. The main results from this project will be published shortly, while other aspects will be carried on by collaborators.

Prosjektet har ført til utveksling av kompetanse mellom utlandet og Norge, og medført nye samarbeid mellom forskningsinstitusjoner, noe som kan føre til nye resultater i fremtiden. Den første publiserte vitenskapelige artikkelen vil demonstrere en effektiv måte å produsere og studere antibiotikatransportører. Dette vil være av stor nytte for forskere i hele verden som jobber med disse utfordrende proteinene. Virkningene av prosjektet i et samfunnsperspektiv er økt kunnskap om antibiotikaresistens og viktigheten av korrekt antibiotikabruk, via populærvitenskapelige produksjoner. Dette kan bremse utvikling av antibiotikaresistens, og føre til mindre risiko for antibiotikaresistente infeksjoner ved sykehusinnleggelser. Langsiktige virkninger av fremtidige publikasjoner inkluderer mer effektiv behandling av antibiotikaresistente infeksjoner. Dette inkluderer både kortere sykehusopphold og høyere kureringsrate.

Multi-resistant tuberculosis is a rising global threat, with approximately 480,000 new cases each year, and with few solutions. One of the mechanisms of resistance is drug efflux, where the bacteria transport antibiotics out of the cells. The ultimate goal of this project is to fight multi-resistant tuberculosis by the development of a new type of drug, targeting these drug-efflux transporters. To achieve this, I will determine the 3D structures and substrates of Major Facilitator Superfamily (MFS) transporters involved in multi-resistant tuberculosis. Structural information is vital for the rational design of inhibitors that will follow from this project. The inhibitors can be developed into drugs to be administered together with traditional antibiotics. This combinatory treatment could increase the efficacy and longevity of existing tuberculosis drugs. Key milestones: 1. Produce protein for structure determination 2. Solve the 3D structures using X-ray crystallography and/or cryo-electron microscopy 3. Identify substrates of the transporters using microbiology Structural determination of membrane proteins is challenging, but manageable with the employment of two strategies: including enough targets and homologs from related mycobacterial species, and the use of two methods for structural characterisation. The project findings will be of interest for pharmaceutical companies, but also for non-governmental organisations spreading awareness of tuberculosis as a global health emergency. There are hundreds of MFS transporters in pathogenic bacteria. The successful development of one MFS drug provides the toolkit to develop more, against other multi-resistant diseases.