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

Meiyan Jiang,Takatoshi Karasawa,Hongzhe Li,Qi Wang,Peter S Steyger,Ja-Won Koo,Ines Armando

doi:10.1371/journal.pone.0108941

Meiyan Jiang, Takatoshi Karasawa + Show 5 more

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https://doi.org/10.1371/journal.pone.0108941

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Journal: PloS one	Publication Date: Sep 30, 2014
Citations: 41	License type: CC BY 4.0

Affiliation: Oregon Health & Science University

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.

Highlights

Aminoglycoside antibiotics, like gentamicin, are essential important clinically for treating critical gram-negative bacterial infections, and are frequently used worldwide [1,2]
sodium-glucose transporter-2 (SGLT2) was immunolocalized at the periphery of KPT2 cells, but not KDT3 cells (Fig. 1A, B, respectively), presumptively at the cell membrane
In KPT2 cells, 2-NBDG fluorescence was primarily localized at the cell periphery (Fig. 1C)

Summary

Introduction

Aminoglycoside antibiotics, like gentamicin, are essential important clinically for treating critical gram-negative bacterial infections, and are frequently used worldwide [1,2]. Both infants and adults receive gentamicin for bacterial meningitis, endocarditis, septicemia and for prophylaxis in premature births and surgical cases. Distal tubule cells are more resistant to gentamicin, most likely because they do not readily take up or retain gentamicin in the cytoplasm [14,16] Another distinguishing feature is the abundant expression of sodium-glucose transporter-2 (SGLT2; a.k.a. SLC5A2) in proximal, but not distal, tubule cells [17,18]

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