title: Sodium-glucose transporter-2 (SGLT2; SLC5A2) enhances cellular uptake of aminoglycosides.
abstract: 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.
authors.affiliation: Oregon Hearing Research Center, Oregon Health & Science University, Portland, Oregon, United States of America.
authors.forename: Meiyan
authors.initials: M
authors.lastname: Jiang
authors.affiliation: Oregon Hearing Research Center, Oregon Health & Science University, Portland, Oregon, United States of America.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Oregon Hearing Research Center, Oregon Health & Science University, Portland, Oregon, United States of America.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Karasawa
authors.affiliation: Oregon Hearing Research Center, Oregon Health & Science University, Portland, Oregon, United States of America; Department of Otorhinolaryngology, Seoul National University College of Medicine, Bundang Hospital, Seongnam, Gyeonggi, Republic of Korea.
authors.forename: Ja-Won
authors.initials: JW
authors.lastname: Koo
authors.affiliation: Oregon Hearing Research Center, Oregon Health & Science University, Portland, Oregon, United States of America.
authors.forename: Hongzhe
authors.initials: H
authors.lastname: Li
authors.affiliation: Oregon Hearing Research Center, Oregon Health & Science University, Portland, Oregon, United States of America.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Steyger
mesh_terms: D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives; D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000633:toxicity; D001692:Biological Transport; D002460:Cell Line; D003051:Cochlea / Q000187:drug effects / Q000502:physiology; D003847:Deoxyglucose / Q000031:analogs & derivatives; D005260:Female; D005456:Fluorescent Dyes; D015870:Gene Expression; D005839:Gentamicins / Q000378:metabolism* / Q000633:toxicity; D006320:Hearing Tests; D007612:Kanamycin / Q000378:metabolism* / Q000633:toxicity; D007686:Kidney Tubules, Distal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009928:Organ Specificity; D010695:Phlorhizin / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D051297:Sodium-Glucose Transporter 2 / Q000235:genetics / Q000378:metabolism*; D000077203:Sodium-Glucose Transporter 2 Inhibitors
chemical_list: D000900:Anti-Bacterial Agents; D005456:Fluorescent Dyes; D005839:Gentamicins; D034741:RNA, Small Interfering; C490299:Slc5a2 protein, mouse; D051297:Sodium-Glucose Transporter 2; D000077203:Sodium-Glucose Transporter 2 Inhibitors; D007612:Kanamycin; D003847:Deoxyglucose; D012964:Sodium; D010695:Phlorhizin; D009327:4-Chloro-7-nitrobenzofurazan; C098340:2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose