PDIM as a Drug Target in Mycobacterium tuberculosis Treatment Investigations and Study of GroEL1 Impact on PDIM.

Confidential, not available.Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie)info:eu-repo/semantics/nonPublishe

The Mycobacterium bovis BCG GroEL1 Contributes to Isoniazid Tolerance in a Dormant-Like State Model

Due to the Mycobacterium tuberculosis complex, including M. tuberculosis and M. bovis, tuberculosis still causes 1.6 million deaths per year. Therefore, efforts to improve tuberculosis treatment are necessary. We previously showed that the GroEL1 protein is involved in antibiotic intrinsic resistance. Indeed, the M. bovis BCG cpn60.1 gene (encoding GroEL1)-disrupted strain (Δcpn60.1) exhibits higher rifampicin and vancomycin susceptibility due to defective cell wall integrity. Here, we show that during hypoxia-triggered growth stasis, in the Wayne dormancy model, the mutant exhibited comparable rifampicin and ethionamide susceptibility but higher isoniazid susceptibility compared to the wild-type strain. Although the Δcpn60.1 strain showed compromised induction of the DosR regulon, growth stasis was achieved, but an ATP burst and a higher reactive oxygen species (ROS) production were observed in the isoniazid-treated Δcpn60.1 strain. GroEL1 could contribute to INH tolerance by reducing ROS

The <i>Mycobacterium bovis</i> BCG GroEL1 Contributes to Isoniazid Tolerance in a Dormant-Like State Model

Due to the Mycobacterium tuberculosis complex, including M. tuberculosis and M. bovis, tuberculosis still causes 1.6 million deaths per year. Therefore, efforts to improve tuberculosis treatment are necessary. We previously showed that the GroEL1 protein is involved in antibiotic intrinsic resistance. Indeed, the M. bovis BCG cpn60.1 gene (encoding GroEL1)-disrupted strain (Δcpn60.1) exhibits higher rifampicin and vancomycin susceptibility due to defective cell wall integrity. Here, we show that during hypoxia-triggered growth stasis, in the Wayne dormancy model, the mutant exhibited comparable rifampicin and ethionamide susceptibility but higher isoniazid susceptibility compared to the wild-type strain. Although the Δcpn60.1 strain showed compromised induction of the DosR regulon, growth stasis was achieved, but an ATP burst and a higher reactive oxygen species (ROS) production were observed in the isoniazid-treated Δcpn60.1 strain. GroEL1 could contribute to INH tolerance by reducing ROS

The Mycobacterium bovis BCG GroEL1 Contributes to Isoniazid Tolerance in a Dormant-Like State Model

info:eu-repo/semantics/publishe

I3-Ag85 effect on phthiodiolone dimycocerosate synthesis

The multiplicity of drug resistant Mycobacterium tuberculosis (Mtb) strains is a growing health issue. New therapies are needed, acting on new targets. The I3-Ag85 was already reported to reduce the amount of trehalose dimycolate lipid of the mycobacterial cell wall. This inhibitor of Ag85C increased the mycobacterial wall permeability. We previously showed that M. tuberculosis strains, even multi-drug resistant and extensively-drug resistant strains, can be susceptible to vancomycin when concomitantly treated with a drug altering the cell envelope integrity. We investigated the effect of the I3-Ag85 on vancomycin susceptibility of M. tuberculosis. Although no synergy was observed, a new target of this drug was discovered: the production of phthiodiolone dimycocerosate (PDIM B).SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Effects of Lipid-Lowering Drugs on Vancomycin Susceptibility of Mycobacteria.

Tuberculosis is still a cause of major concern, partly due to the emergence of multidrug-resistant strains. New drugs are therefore needed. Vancomycin can target mycobacteria with cell envelope deficiency. In this study, we used a vancomycin susceptibility assay to detect drugs hampering lipid synthesis in Mycobacterium bovis BCG and in Mycobacterium tuberculosis We tested three drugs already used to treat human obesity: tetrahydrolipstatin (THL), simvastatin, and fenofibrate. Only vancomycin and THL were able to synergize on M. bovis BCG and on M. tuberculosis, although mycobacteria could also be inhibited by simvastatin alone. Lipid analysis allowed us to identify several lipid modifications in M. tuberculosis H37Rv treated with those drugs. THL treatment mainly reduced the phthiocerol dimycocerosate (PDIM) content in the mycobacterial cell wall, providing an explanation for the synergy, since PDIM deficiency has been related to vancomycin susceptibility. Proteomic analysis suggested that bacteria treated with THL, in contrast to bacteria treated with simvastatin, tried to recover, inducing, among other reactions, lipid synthesis. The combination of THL and vancomycin should be considered a promising solution in developing new strategies to treat multidrug-resistant tuberculosis.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Increased vancomycin susceptibility in mycobacteria: a new approach to identify synergistic activity against multi-drug resistant mycobacteria.

Mycobacterium tuberculosis is wrapped in complex waxes, impermeable to most antibiotics. Comparing M. bovis BCG and M. tuberculosis mutants, lacking phthiocerol dimycocerosates (PDIM) and/or phenolic glycolipids, with wild-type strains, we observed that glycopeptides strongly inhibited PDIM deprived mycobacteria. Vancomycin together with a drug targeting lipids synthesis inhibited multidrug-resistant (MDR) and extensively-drug resistant (XDR) clinical isolates. Our study puts glycopeptides in the pipeline of potential anti-TB agents and might provide a new antimycobacterial drug-screening strategy.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Cpn60.1/GroEL-1/Hsp60-1, a New Potential Antimycobacterial Drug Target Involved in Antibiotics Resistance.

The phenolic glycolipids (PGL) and the related phthiocerol and phthiodolone dimycocerosates (PDIM) are known to be essential for Mycobacterium tuberculosis infection in human tuberculosis. By studying a mutant M. bovis BCG strain, Δcpn60.1, unable to express Hsp60-1/GroEL-1/Cpn60-1 mycobacterial chaperone, we discovered that not only this strain is PDIM and PGL negative, but is also very sensitive to glycopeptide antibiotics. Proteins and RNA analyses allowed identifying a defect in the PpsA-E proteins expression. Proteomic analysis further suggested that other proteins, namely FadD26 and DrrA, involved in PDIM biosynthesis and transport, respectively, could also be reduced. Furthermore, the association of drugs targeting the cell wall biosynthesis and glycopeptides can synergistically inhibit multi-drug-resistant and extremely resistant strains. Overall, our study firstly emphasized the potential of Cpn60-1, or PpsE targeting drugs and puts glycopeptides in a good position in the pipeline of potential antibiotics to fight against tuberculosis

Effects of Lipid-Lowering Drugs on Vancomycin Susceptibility of Mycobacteria

Tuberculosis is still a cause of major concern, partly due to the emergence of multidrug-resistant strains. New drugs are therefore needed. Vancomycin can target mycobacteria with cell envelope deficiency. In this study, we used a vancomycin susceptibility assay to detect drugs hampering lipid synthesis in Mycobacterium bovis BCG and in Mycobacterium tuberculosis We tested three drugs already used to treat human obesity: tetrahydrolipstatin (THL), simvastatin, and fenofibrate. Only vancomycin and THL were able to synergize on M. bovis BCG and on M. tuberculosis, although mycobacteria could also be inhibited by simvastatin alone. Lipid analysis allowed us to identify several lipid modifications in M. tuberculosis H37Rv treated with those drugs. THL treatment mainly reduced the phthiocerol dimycocerosate (PDIM) content in the mycobacterial cell wall, providing an explanation for the synergy, since PDIM deficiency has been related to vancomycin susceptibility. Proteomic analysis suggested that bacteria treated with THL, in contrast to bacteria treated with simvastatin, tried to recover, inducing, among other reactions, lipid synthesis. The combination of THL and vancomycin should be considered a promising solution in developing new strategies to treat multidrug-resistant tuberculosis.SCOPUS: ar.jinfo:eu-repo/semantics/publishe