title: Cellular pharmacokinetics and intracellular activity of the novel peptide deformylase inhibitor GSK1322322 against Staphylococcus aureus laboratory and clinical strains with various resistance phenotypes: studies with human THP-1 monocytes and J774 murine macrophages.
abstract: GSK1322322 is a peptide deformylase inhibitor active against Staphylococcus aureus strains resistant to currently marketed antibiotics. Our aim was to assess the activity of GSK1322322 against intracellular S. aureus using an in vitro pharmacodynamic model and, in parallel, to examine its cellular pharmacokinetics and intracellular disposition. For intracellular activity analysis, we used an established model of human THP-1 monocytes and tested one fully susceptible S. aureus strain (ATCC 25923) and 8 clinical strains with resistance to oxacillin, vancomycin, daptomycin, macrolides, clindamycin, linezolid, or moxifloxacin. Uptake, accumulation, release, and subcellular distribution (cell fractionation) of [(14)C]GSK1322322 were examined in uninfected murine J774 macrophages and uninfected and infected THP-1 monocytes. GSK1322322 demonstrated a uniform activity against the intracellular forms of all S. aureus strains tested, disregarding their resistance phenotypes, with a maximal relative efficacy (E max) of a 0.5 to 1 log10 CFU decrease compared to the original inoculum within 24 h and a static concentration (C s) close to its MIC in broth. Influx and efflux were very fast (<5 min to equilibrium), and accumulation was about 4-fold, with no or a minimal effect of the broad-spectrum eukaryotic efflux transporter inhibitors gemfibrozil and verapamil. GSK1322322 was recovered in the cell-soluble fraction and was dissociated from the main subcellular organelles and from bacteria (in infected cells). The results of this study show that GSK1322322, as a typical novel deformylase inhibitor, may act against intracellular forms of S. aureus. They also suggest that GSK1322322 has the ability to freely diffuse into and out of eukaryotic cells as well as within subcellular compartments.
authors.affiliation: Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Peyrusson
authors.affiliation: GlaxoSmithKline, Collegeville, Pennsylvania, USA.
authors.forename: Deborah
authors.initials: D
authors.lastname: Butler
authors.affiliation: Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium.
authors.forename: Paul M
authors.identifier: http://orcid.org/0000-0002-7121-3623
authors.initials: PM
authors.lastname: Tulkens
authors.affiliation: Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium francoise.vanbambeke@uclouvain.be.
authors.forename: Françoise
authors.identifier: http://orcid.org/0000-0002-0052-7991
authors.initials: F
authors.lastname: Van Bambeke
mesh_terms: D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000493:pharmacokinetics*; D002460:Cell Line; D006801:Humans; D006877:Hydroxamic Acids / Q000493:pharmacokinetics*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D009000:Monocytes / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000472:pathogenicity*
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; C583947:GSK1322322; D006877:Hydroxamic Acids