TRPV4 enhances the cellular uptake of aminoglycoside antibiotics

J Cell Sci. 2008 Sep 1;121(Pt 17):2871-9. doi: 10.1242/jcs.023705. Epub 2008 Aug 5.

Abstract

The cochlea and kidney are susceptible to aminoglycoside-induced toxicity. The non-selective cation channel TRPV4 is expressed in kidney distal tubule cells, and hair cells and the stria vascularis in the inner ear. To determine whether TRPV4 is involved in aminoglycoside trafficking, we generated a murine proximal-tubule cell line (KPT2) and a distal-tubule cell line (KDT3). TRPV4 expression was confirmed in KDT3 cells but not in KPT2 cells. Removal of extracellular Ca(2+) significantly enhanced gentamicin-Texas-Red (GTTR) uptake by KDT3, indicative of permeation through non-selective cation channels. To determine whether TRPV4 is permeable to GTTR, stable cell lines were generated that express TRPV4 in KPT2 (KPT2-TRPV4). KPT2-TRPV4 cells took up more GTTR than control cell lines (KPT2-pBabe) in the absence of extracellular Ca(2+). TRPV4-dependent GTTR uptake was abolished by a point mutation within the crucial pore region of the channel, suggesting that GTTR permeates the TRPV4 channel. In an endolymph-like extracellular environment, clearance of GTTR was attenuated from KPT2-TRPV4 cells in a TRPV4-dependent fashion. We propose that TRPV4 has a role in aminoglycoside uptake and retention in the cochlea.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminoglycosides / metabolism*
  • Animals
  • Anti-Bacterial Agents / metabolism*
  • Calcium / pharmacology
  • Cell Line
  • Dogs
  • Ear, Inner / cytology
  • Ear, Inner / metabolism
  • Endolymph / drug effects
  • Endolymph / metabolism
  • Extracellular Space / drug effects
  • Extracellular Space / metabolism
  • Gentamicins / metabolism
  • Kidney / cytology
  • Kidney / metabolism
  • Methionine / metabolism
  • Mice
  • Rats
  • TRPV Cation Channels / metabolism*
  • Xanthenes / metabolism

Substances

  • Aminoglycosides
  • Anti-Bacterial Agents
  • Gentamicins
  • TRPV Cation Channels
  • Trpv4 protein, rat
  • Xanthenes
  • Texas red
  • Methionine
  • Calcium