Universitą degli studi di Pavia
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Battaglia Simone research activity
New antitubercular drugs: study of cellular targets, mechanism of action and of resistance
Tuberculosis (TB) is getting seriously problematic since the emergence of HIV and the appearance of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains, which are MDR also resistant to at least three second-line drugs. Therefore, new drugs are needed.
A new compound, BM212, shows a potent activity against M. tuberculosis, non-tuberculosis mycobacteria, MDR clinical isolates and intracellular bacilli. On the basis of these results, BM212 is considered a lead compound among 1,5-diarylpyrrole derivatives and a promising antimycobacterial drug.
In the last years, the research work in the General Microbiology Laboratory, directed by Prof.ssa E. De Rossi, is focused on the identification and characterization of BM212 target in M. smegmatis. To this aim, resistant mutants were isolated and characterized, allowing the identification of three proteins as possible BM212 targets. All the mutations identified map in the mmpL3 gene, coding for a membrane protein with unknown function. Since mutations in the target gene are responsible for drug resistance, the MmpL3 protein seems to be the cellular target of BM212.
MmpL proteins show similarity with RND family of efflux pumps, able to extrude structurally and functionally unrelated compounds out of the cell. Uptake/efflux experiments demonstrated that MmpL3 does not extrude BM212, suggesting that this protein is not an efflux pump. To validate this target, the inactivation of mmpL3 in M. smegmatis and M. bovis BCG was planned. Until now, the inactivation attempts were unsuccessful, indicating the possible essentiality of this gene for the cellular growth of mycobacteria.
The aim of my research project is to demonstrate the essentiality of mmpL3 and to try the expression and purification of the MmpL3 protein in heterologous hosts in order to understand the cellular function and to determine the structure of this new target. This would allow us to demonstrate not only if the MmpL3 protein is the target of BM212, but also if it is an essential target, as well as to determine its function.
Tuberculosis (TB) is getting seriously problematic since the emergence of HIV and the appearance of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains, which are MDR also resistant to at least three second-line drugs. Therefore, new drugs are needed.
A new compound, BM212, shows a potent activity against M. tuberculosis, non-tuberculosis mycobacteria, MDR clinical isolates and intracellular bacilli. On the basis of these results, BM212 is considered a lead compound among 1,5-diarylpyrrole derivatives and a promising antimycobacterial drug.
In the last years, the research work in the General Microbiology Laboratory, directed by Prof.ssa E. De Rossi, is focused on the identification and characterization of BM212 target in M. smegmatis. To this aim, resistant mutants were isolated and characterized, allowing the identification of three proteins as possible BM212 targets. All the mutations identified map in the mmpL3 gene, coding for a membrane protein with unknown function. Since mutations in the target gene are responsible for drug resistance, the MmpL3 protein seems to be the cellular target of BM212.
MmpL proteins show similarity with RND family of efflux pumps, able to extrude structurally and functionally unrelated compounds out of the cell. Uptake/efflux experiments demonstrated that MmpL3 does not extrude BM212, suggesting that this protein is not an efflux pump. To validate this target, the inactivation of mmpL3 in M. smegmatis and M. bovis BCG was planned. Until now, the inactivation attempts were unsuccessful, indicating the possible essentiality of this gene for the cellular growth of mycobacteria.
The aim of my research project is to demonstrate the essentiality of mmpL3 and to try the expression and purification of the MmpL3 protein in heterologous hosts in order to understand the cellular function and to determine the structure of this new target. This would allow us to demonstrate not only if the MmpL3 protein is the target of BM212, but also if it is an essential target, as well as to determine its function.
