Sodium-glucose transporter-2 (SGLT2; SLC5A2) enhances cellular uptake of aminoglycosides

• Published in: PloS one 2014-09, Vol.9 (9), p.e108941
• Main Authors: Jiang, Meiyan, Wang, Qi, Karasawa, Takatoshi, Koo, Ja-Won, Li, Hongzhe, Steyger, Peter S
• Format: Article
• Language: English
• Subjects: 4-Chloro-7-nitrobenzofurazan - analogs & derivatives; Aminoglycoside antibiotics; Aminoglycosides; Animals; Antagonism; Anti-Bacterial Agents - metabolism; Anti-Bacterial Agents - toxicity; Antibacterial agents; Antibiotics; Apoptosis; Auditory system; Bacteria; Bacterial diseases; Bacterial infections; Biocompatibility; Biological Transport; Biology and Life Sciences; Cell Line; Clonal deletion; Cochlea; Cochlea - drug effects; Cochlea - physiology; Complications; Cytotoxicity; Deoxyglucose; Deoxyglucose - analogs & derivatives; Drugs; Female; Fluorescence; Fluorescent Dyes; Gene deletion; Gene Expression; Gene therapy; Gentamicin; Gentamicins - metabolism; Gentamicins - toxicity; Glucose; Glucose transporter; Health aspects; Hearing Tests; Kanamycin; Kanamycin - metabolism; Kanamycin - toxicity; Kidney Tubules, Distal - cytology; Kidney Tubules, Distal - drug effects; Kidney Tubules, Distal - metabolism; Kidney Tubules, Proximal - cytology; Kidney Tubules, Proximal - drug effects; Kidney Tubules, Proximal - metabolism; Kidneys; Kinetics; Localization; Male; Medicine and Health Sciences; Mice; Mice, Transgenic; Organ Specificity; Otolaryngology; Ototoxicity; Oxalic acid; Phlorhizin - pharmacology; Physiology; Proximal tubules; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; Rodents; Science; Side effects; siRNA; Sodium; Sodium - metabolism; Sodium-glucose cotransporter; Sodium-Glucose Transporter 2 - genetics; Sodium-Glucose Transporter 2 - metabolism; Sodium-Glucose Transporter 2 Inhibitors; Toxicity
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0108941

Aminoglycoside antibiotics, like gentamicin, continue to be clinically essential worldwide to treat life-threatening bacterial infections. Yet, the ototoxic and nephrotoxic side-effects of these drugs remain serious complications. A major site of gentamicin uptake and toxicity resides within kidney proximal tubules that also heavily express electrogenic sodium-glucose transporter-2 (SGLT2; SLC5A2) in vivo. We hypothesized that SGLT2 traffics gentamicin, and promotes cellular toxicity. We confirmed in vitro expression of SGLT2 in proximal tubule-derived KPT2 cells, and absence in distal tubule-derived KDT3 cells. D-glucose competitively decreased the uptake of 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), a fluorescent analog of glucose, and fluorescently-tagged gentamicin (GTTR) by KPT2 cells. Phlorizin, an SGLT2 antagonist, strongly inhibited uptake of 2-NBDG and GTTR by KPT2 cells in a dose- and time-dependent manner. GTTR uptake was elevated in KDT3 cells transfected with SGLT2 (compared to controls); and this enhanced uptake was attenuated by phlorizin. Knock-down of SGLT2 expression by siRNA reduced gentamicin-induced cytotoxicity. In vivo, SGLT2 was robustly expressed in kidney proximal tubule cells of heterozygous, but not null, mice. Phlorizin decreased GTTR uptake by kidney proximal tubule cells in Sglt2+/- mice, but not in Sglt2-/- mice. However, serum GTTR levels were elevated in Sglt2-/- mice compared to Sglt2+/- mice, and in phlorizin-treated Sglt2+/- mice compared to vehicle-treated Sglt2+/- mice. Loss of SGLT2 function by antagonism or by gene deletion did not affect gentamicin cochlear loading or auditory function. Phlorizin did not protect wild-type mice from kanamycin-induced ototoxicity. We conclude that SGLT2 can traffic gentamicin and contribute to gentamicin-induced cytotoxicity.