title: Mitochondrial superoxide production contributes to vancomycin-induced renal tubular cell apoptosis.
abstract: Vancomycin chloride (VCM), a glycopeptide antibiotic, is widely used for the therapy of infections caused by methicillin-resistant Staphylococcus aureus. However, nephrotoxicity is a major adverse effect in VCM therapy. In this study, we investigated the cellular mechanisms underlying VCM-induced renal tubular cell injury in cultured LLC-PK1 cells. VCM induced a concentration- and time-dependent cell injury in LLC-PK1 cells. VCM caused increases in the numbers of annexin V-positive/PI-negative cells and TUNEL-positive cells, indicating the involvement of apoptotic cell death in VCM-induced renal cell injury. The VCM-induced apoptosis was accompanied by the activation of caspase-9 and caspase-3/7 and reversed by inhibitors of these caspases. Moreover, VCM caused an increase in intracellular reactive oxygen species production and mitochondrial membrane depolarization, which were reversed by vitamin E. In addition, mitochondrial complex I activity was inhibited by VCM as well as by the complex I inhibitor rotenone, and rotenone mimicked the VCM-induced LLC-PK1 cell injury. These findings suggest that VCM causes apoptotic cell death in LLC-PK1 cells by enhancing mitochondrial superoxide production leading to mitochondrial membrane depolarization followed by the caspase activities. Moreover, mitochondrial complex I may play an important role in superoxide production and renal tubular cell apoptosis induced by VCM.
authors.affiliation: Department of Pharmacy, Kyushu University Hospital, Fukuoka 812-8582, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Arimura
authors.forename: Takahisa
authors.initials: T
authors.lastname: Yano
authors.forename: Megumi
authors.initials: M
authors.lastname: Hirano
authors.forename: Yuya
authors.initials: Y
authors.lastname: Sakamoto
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Egashira
authors.forename: Ryozo
authors.initials: R
authors.lastname: Oishi
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D005434:Flow Cytometry; D020287:In Situ Nick-End Labeling; D007684:Kidney Tubules / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D018374:LLC-PK1 Cells; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D013552:Swine; D014640:Vancomycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D013481:Superoxides; D014640:Vancomycin; D045304:Cytochromes c; D013482:Superoxide Dismutase; D020169:Caspases