title: Improved efficacy of fosmidomycin against Plasmodium and Mycobacterium species by combination with the cell-penetrating peptide octaarginine.
abstract: Cellular drug delivery can improve efficacy and render intracellular pathogens susceptible to compounds that cannot permeate cells. The transport of physiologically active compounds across membranes into target cells can be facilitated by cell-penetrating peptides (CPPs), such as oligoarginines. Here, we investigated whether intracellular delivery of the drug fosmidomycin can be improved by combination with the CPP octaarginine. Fosmidomycin is an antibiotic that inhibits the second reaction in the nonmevalonate pathway of isoprenoid biosynthesis, an essential pathway for many obligate intracellular pathogens, including mycobacteria and apicomplexan parasites. We observed a strict correlation between octaarginine host cell permeability and its ability to improve the efficacy of fosmidomycin. Plasmodium berghei liver-stage parasites were only partially susceptible to an octaarginine-fosmidomycin complex. Similarly, Toxoplasma gondii was only susceptible during the brief extracellular stages. In marked contrast, a salt complex of octaarginine and fosmidomycin greatly enhanced efficacy against blood-stage Plasmodium falciparum. This complex and a covalently linked conjugate of octaarginine and fosmidomycin also reverted resistance of Mycobacteria to fosmidomycin. These findings provide chemical genetic evidence for vital roles of the nonmevalonate pathway of isoprenoid biosynthesis in a number of medically relevant pathogens. Our results warrant further investigation of octaarginine as a delivery vehicle and alternative fosmidomycin formulations for malaria and tuberculosis drug development.
authors.affiliation: ETH-Zürich, Laboratorium für Organische Chemie, Departement für Chemie und Angewandte Biowissenschaften, Hönggerberg HCI, Zürich, Switzerland.
authors.forename: Christof
authors.initials: C
authors.lastname: Sparr
authors.forename: Nirupam
authors.initials: N
authors.lastname: Purkayastha
authors.forename: Beata
authors.initials: B
authors.lastname: Kolesinska
authors.forename: Martin
authors.initials: M
authors.lastname: Gengenbacher
authors.forename: Borko
authors.initials: B
authors.lastname: Amulic
authors.forename: Kai
authors.initials: K
authors.lastname: Matuschewski
authors.forename: Dieter
authors.initials: D
authors.lastname: Seebach
authors.forename: Faustin
authors.initials: F
authors.lastname: Kamena
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000962:Antimalarials / Q000494:pharmacology*; D057846:Cell-Penetrating Peptides / Q000737:chemistry / Q000494:pharmacology*; D004357:Drug Synergism; D005578:Fosfomycin / Q000031:analogs & derivatives* / Q000494:pharmacology; D009161:Mycobacterium / Q000187:drug effects; D009842:Oligopeptides / Q000494:pharmacology*; D010961:Plasmodium / Q000187:drug effects*; D014122:Toxoplasma / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000962:Antimalarials; D057846:Cell-Penetrating Peptides; D009842:Oligopeptides; C448619:octaarginine; D005578:Fosfomycin; C024640:fosmidomycin