title: Significant accumulation of polymyxin in single renal tubular cells: a medicinal chemistry and triple correlative microscopy approach.
abstract: Polymyxin is the last-line therapy against Gram-negative 'superbugs'; however, dose-limiting nephrotoxicity can occur in up to 60% of patients after intravenous administration. Understanding the accumulation and concentration of polymyxin within renal tubular cells is essential for the development of novel strategies to ameliorate its nephrotoxicity and to develop safer, new polymyxins. We designed and synthesized a novel dual-modality iodine-labeled fluorescent probe for quantitative mapping of polymyxin in kidney proximal tubular cells. Measured by synchrotron X-ray fluorescence microscopy, polymyxin concentrations in single rat (NRK-52E) and human (HK-2) kidney tubular cells were approximately 1930- to 4760-fold higher than extracellular concentrations. Our study is the first to quantitatively measure the significant uptake of polymyxin in renal tubular cells and provides crucial information for the understanding of polymyxin-induced nephrotoxicity. Importantly, our approach represents a significant methodological advancement in determination of drug uptake for single-cell pharmacology.
authors.affiliation: Drug Delivery, Disposition and Dynamics, and ‡Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.
authors.forename: Mohammad A K
authors.initials: MA
authors.lastname: Azad
authors.forename: Kade D
authors.initials: KD
authors.lastname: Roberts
authors.forename: Heidi H
authors.initials: HH
authors.lastname: Yu
authors.forename: Boyin
authors.initials: B
authors.lastname: Liu
authors.forename: Alice V
authors.initials: AV
authors.lastname: Schofield
authors.forename: Simon A
authors.initials: SA
authors.lastname: James
authors.forename: Daryl L
authors.initials: DL
authors.lastname: Howard
authors.forename: Roger L
authors.initials: RL
authors.lastname: Nation
authors.forename: Kelly
authors.initials: K
authors.lastname: Rogers
authors.forename: Martin D
authors.initials: MD
authors.lastname: de Jonge
authors.forename: Philip E
authors.initials: PE
authors.lastname: Thompson
authors.forename: Jing
authors.initials: J
authors.lastname: Fu
authors.forename: Tony
authors.initials: T
authors.lastname: Velkov
authors.forename: Jian
authors.initials: J
authors.lastname: Li
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000378:metabolism*; D002478:Cells, Cultured; D002626:Chemistry, Pharmaceutical; D005456:Fluorescent Dyes; D006801:Humans; D007457:Iodine Radioisotopes; D007684:Kidney Tubules / Q000166:cytology / Q000378:metabolism*; D008856:Microscopy, Fluorescence / Q000379:methods*; D008958:Models, Molecular; D018384:Oxidative Stress; D011113:Polymyxins / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D059010:Single-Cell Analysis / Q000379:methods*; D017356:Synchrotrons; D014965:X-Rays
chemical_list: D000900:Anti-Bacterial Agents; D005456:Fluorescent Dyes; D007457:Iodine Radioisotopes; D011113:Polymyxins