title: Cellular Uptake and Localization of Polymyxins in Renal Tubular Cells Using Rationally Designed Fluorescent Probes.
abstract: Polymyxins are cyclic lipopeptide antibiotics that serve as a last line of defense against Gram-negative bacterial superbugs. However, the extensive accumulation of polymyxins in renal tubular cells can lead to nephrotoxicity, which is the major dose-limiting factor in clinical use. In order to gain further insights into the mechanism of polymyxin-induced nephrotoxicity, we have rationally designed novel fluorescent polymyxin probes to examine the localization of polymyxins in rat renal tubular (NRK-52E) cells. Our design strategy focused on incorporating a dansyl fluorophore at the hydrophobic centers of the polymyxin core structure. To this end, four novel regioselectively labeled monodansylated polymyxin B probes (MIPS-9541, MIPS-9542, MIPS-9543, and MIPS-9544) were designed, synthesized, and screened for their antimicrobial activities and apoptotic effects against rat kidney proximal tubular cells. On the basis of the assessment of antimicrobial activities, cellular uptake, and apoptotic effects on renal tubular cells, incorporation of a dansyl fluorophore at either position 6 or 7 (MIPS-9543 and MIPS-9544, respectively) of the polymyxin core structure appears to be an appropriate strategy for generating representative fluorescent polymyxin probes to be utilized in intracellular imaging and mechanistic studies. Furthermore, confocal imaging experiments utilizing these probes showed evidence of partial colocalization of the polymyxins with both the endoplasmic reticulum and mitochondria in rat renal tubular cells. Our results highlight the value of these new fluorescent polymyxin probes and provide further insights into the mechanism of polymyxin-induced nephrotoxicity.
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Bo
authors.initials: B
authors.lastname: Yun
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Mohammad A K
authors.initials: MA
authors.lastname: Azad
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Cameron J
authors.initials: CJ
authors.lastname: Nowell
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Roger L
authors.initials: RL
authors.lastname: Nation
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Philip E
authors.initials: PE
authors.lastname: Thompson
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Kade D
authors.initials: KD
authors.lastname: Roberts
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia Velkov@monash.edu colistin.polymyxin@gmail.com.
authors.forename: Tony
authors.initials: T
authors.lastname: Velkov
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia Velkov@monash.edu colistin.polymyxin@gmail.com.
authors.forename: Jian
authors.initials: J
authors.lastname: Li
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects / Q000254:growth & development; D000818:Animals; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001692:Biological Transport; D002460:Cell Line; D003619:Dansyl Compounds / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D015195:Drug Design; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D057927:Hydrophobic and Hydrophilic Interactions; D007684:Kidney Tubules / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D057054:Molecular Imaging / Q000379:methods; D011112:Polymyxin B / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development; D051381:Rats
chemical_list: D000900:Anti-Bacterial Agents; D003619:Dansyl Compounds; D005456:Fluorescent Dyes; D011112:Polymyxin B