Research experience
-
Jan 2004–
Dec 2012Research: Università degli studi di Pavia
Università degli studi di Pavia · Department of Biology and Biotechnology "Lazzaro Spallanzani"Italy · Pavia
Publications (29) View all
-
Article: Improved BM212 MmpL3 Inhibitor Analogue Shows Efficacy in Acute Murine Model of Tuberculosis Infection.
[show abstract] [hide abstract]
ABSTRACT: 1,5-Diphenyl pyrroles were previously identified as a class of compounds endowed with high in vitro efficacy against M. tuberculosis. To improve the physical chemical properties and drug-like parameters of this class of compounds, a medicinal chemistry effort was undertaken. By selecting the optimal substitution patterns for the phenyl rings at N1 and C5 and by replacing the thiomorpholine moiety with a morpholine one, a new series of compounds was produced. The replacement of the sulfur with oxygen gave compounds with lower lipophilicity and improved invitro microsomal stability. Moreover, since the parent compound of this family has been shown to target MmpL3, mycobacterial mutants resistant to two compounds have been isolated and characterized by sequencing the mmpL3 gene; all the mutants showed point mutations in this gene. The best compound identified to date was progressed to dose-response studies in an acute murine TB infection model. The resulting ED(99) of 49 mg/Kg is within the range of commonly employed tuberculosis drugs, demonstrating the potential of this chemical series. The in vitro and in vivo target validation evidence presented here adds further weight to MmpL3 as a druggable target of interest for anti-tubercular drug discovery.PLoS ONE 01/2013; 8(2):e56980. · 4.09 Impact Factor -
Article: Phenotypic and Genotypic Characterisation of Burkholderia cenocepacia J2315 Mutants Affected in Homoserine Lactone and Diffusible Signal Factor-Based Quorum Sensing Systems Suggests Interplay between Both Types of Systems.
[show abstract] [hide abstract]
ABSTRACT: Many putative virulence factors of Burkholderia cenocepacia are controlled by various quorum sensing (QS) circuits. These QS systems either use N-acyl homoserine lactones (AHL) or cis-2-dodecenoic acid ("Burkholderia diffusible signal factor", BDSF) as signalling molecules. Previous work suggested that there is little cross-talk between both types of systems. We constructed mutants in B. cenocepacia strain J2315, in which genes encoding CepI (BCAM1870), CciI (BCAM0239a) and the BDSF synthase (BCAM0581) were inactivated, and also constructed double (ΔcepIΔBCAM0581, ΔcciIΔBCAM0581 and ΔcepIΔcciI) mutants and a triple (ΔcepIΔcciIΔBCAM0581) mutant. Subsequently we investigated phenotypic properties (antibiotic susceptibility, biofilm formation, production of AHL and BDSF, protease activity and virulence in Caenorhabditis elegans) and measured gene expression in these mutants, and this in the presence and absence of added BDSF, AHL or both. The triple mutant was significantly more affected in biofilm formation, antimicrobial susceptibility, virulence in C. elegans, and protease production than either the single or double mutants. The ΔBCAM0581 mutant and the ΔcepIΔBCAM0581 and ΔcciIΔBCAM0581 double mutants produced significantly less AHL compared to the WT strain and the ΔcepI and ΔcciI single mutant, respectively. The expression of cepI and cciI in ΔBCAM0581, was approximately 3-fold and 7-fold (p<0.05) lower than in the WT, respectively. The observed differences in AHL production, expression of cepI and cciI and QS-controlled phenotypes in the ΔBCAM0581 mutant could (at least partially) be restored by addition of BDSF. Our data suggest that, in B. cenocepacia J2315, AHL and BDSF-based QS systems co-regulate the same set of genes, regulate different sets of genes that are involved in the same phenotypes and/or that the BDSF system controls the AHL-based QS system. As the expression of the gene encoding the C6-HSL synthase CciI (and to a lesser extent the C8-HSL synthase CepI) is partially controlled by BDSF, it seems likely that the BDSF QS systems controls AHL production through this system.PLoS ONE 01/2013; 8(1):e55112. · 4.09 Impact Factor -
Article: Structural Basis for Benzothiazinone-Mediated Killing of Mycobacterium tuberculosis.
[show abstract] [hide abstract]
ABSTRACT: The benzothiazinone BTZ043 is a tuberculosis drug candidate with nanomolar whole-cell activity. BTZ043 targets the DprE1 catalytic component of the essential enzyme decaprenylphosphoryl-β-d-ribofuranose-2'-epimerase, thus blocking biosynthesis of arabinans, vital components of mycobacterial cell walls. Crystal structures of DprE1, in its native form and in a complex with BTZ043, reveal formation of a semimercaptal adduct between the drug and an active-site cysteine, as well as contacts to a neighboring catalytic lysine residue. Kinetic studies confirm that BTZ043 is a mechanism-based, covalent inhibitor. This explains the exquisite potency of BTZ043, which, when fluorescently labeled, localizes DprE1 at the poles of growing bacteria. Menaquinone can reoxidize the flavin adenine dinucleotide cofactor in DprE1 and may be the natural electron acceptor for this reaction in the mycobacterium. Our structural and kinetic analysis provides both insight into a critical epimerization reaction and a platform for structure-based design of improved inhibitors.Science translational medicine 09/2012; 4(150):150ra121. · 7.80 Impact Factor -
Article: Chemical synthesis and biological evaluation of triazole derivatives as inhibitors of InhA and antituberculosis agents.
[show abstract] [hide abstract]
ABSTRACT: A series of triazoles have been prepared and evaluated as inhibitors of InhA as well as inhibitors of Mycobacterium tuberculosis H(37)R(v). Several of these new compounds possess a good activity against InhA, particularly compounds 17 and 18 for which molecular docking has been performed. Concerning their activities against M. tuberculosis H(37)R(V) strain, two of them, 3 and 12, were found to be good inhibitors with MIC values of 0.50 and 0.25 μg/mL, respectively. Particularly, compound 12 presenting the best MIC value of all compounds tested (0.6 μM) is totally inactive against InhA.European journal of medicinal chemistry 03/2012; 52:275-83. · 3.27 Impact Factor -
Chapter: Fighting Against Resistant Strains: The Case of Benzothiazinones and Dinitrobenzamides
02/2012; , ISBN: 978-953-307-948-6
