title: Short-term exposure of renal proximal tubules to gentamicin increases long-term multidrug resistance protein 2 (Abcc2) transport function and reduces nephrotoxicant sensitivity.
abstract: We previously showed that the function of renal multidrug resistance protein (Mrp) 2 (Abcc2) is reduced by endothelin (ET)-1 signaling through an ET(B) receptor, nitric-oxide synthase (NOS), cGMP, and protein kinase C and that this pathway was activated by several nephrotoxicants (Masereeuw et al., 2000; Terlouw et al., 2001; Notenboom et al., 2002, 2004). Here, we determined the long-term effects on Mrp2-mediated transport (luminal fluorescein methotrexate accumulation) of short-term (30 min) exposure to ET-1 and the aminoglycoside antibiotic, gentamicin. Our data show that over the 3 h following exposure, proximal tubules recovered fully from the initial decrease in Mrp2-mediated transport and that transport activity was not changed 9 h later. However, 24 h after exposure, luminal accumulation of an Mrp2 substrate had increased by 50%. Increased transport at 24 h was accompanied by an increased transporter protein content of the luminal plasma membrane as measured by immunostaining. Blocking ET-1 signaling at the ET(B) receptor or downstream at NOS or guanylyl cyclase abolished both stimulation of transport and increased transporter expression. Thus, regardless of whether signaling was initiated by a short exposure to ET-1 or to a nephrotoxicant, the time course of Mrp2 response to ET(B) signaling was the same and was multiphasic. Finally, when tubules were exposed to gentamicin for 30 min and removed to gentamicin-free medium for 24 h, they were less sensitive to acute gentamicin toxicity than paired controls not initially exposed to the drug. Thus, short-term exposure to ET-1 or gentamicin resulted in long-term protection against a second insult.
authors.affiliation: Department of Pharmacology and Toxicology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, The Netherlands.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Notenboom
authors.forename: David S
authors.initials: DS
authors.lastname: Miller
authors.forename: Leon H
authors.initials: LH
authors.lastname: Kuik
authors.forename: Paul
authors.initials: P
authors.lastname: Smits
authors.forename: Frans G M
authors.initials: FG
authors.lastname: Russel
authors.forename: Rosalinde
authors.initials: R
authors.lastname: Masereeuw
mesh_terms: D000818:Animals; D006152:Cyclic GMP / Q000378:metabolism; D004351:Drug Resistance; D004791:Enzyme Inhibitors / Q000494:pharmacology; D023781:Fundulidae; D005839:Gentamicins / Q000494:pharmacology*; D007150:Immunohistochemistry; D007674:Kidney Diseases / Q000139:chemically induced* / Q000473:pathology; D007687:Kidney Tubules, Proximal / Q000187:drug effects* / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D017466:Receptors, Endothelin / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D006152:Cyclic GMP; D004791:Enzyme Inhibitors; D005839:Gentamicins; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D011500:Protein Synthesis Inhibitors; D017466:Receptors, Endothelin