This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Marquez, B.
Right arrow Articles by Van Bambeke, F.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Marquez, B.
Right arrow Articles by Van Bambeke, F.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, June 2009, p. 2410-2416, Vol. 53, No. 6
0066-4804/09/$08.00+0     doi:10.1128/AAC.01428-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Identification of the Efflux Transporter of the Fluoroquinolone Antibiotic Ciprofloxacin in Murine Macrophages: Studies with Ciprofloxacin-Resistant Cells{triangledown}

Béatrice Marquez, Nancy E. Caceres,{dagger} Marie-Paule Mingeot-Leclercq, Paul M. Tulkens, and Françoise Van Bambeke*

Unité de Pharmacologie Cellulaire et Moléculaire, Louvain Drug Research Institute, Université Catholique de Louvain, B-1200 Brussels, Belgium

Received 23 October 2008/ Returned for modification 3 March 2009/ Accepted 16 March 2009

Ciprofloxacin, the most widely used totally synthetic antibiotic, is subject to active efflux mediated by a MRP-like transporter in wild-type murine J774 macrophages. To identify the transporter among the seven potential Mrps, we used cells made resistant to ciprofloxacin obtained by long-term exposure to increasing drug concentrations (these cells show less ciprofloxacin accumulation and provide a protected niche for ciprofloxacin-sensitive intracellular Listeria monocytogenes). In the present paper, we first show that ciprofloxacin-resistant cells display a faster efflux of ciprofloxacin which is inhibited by gemfibrozil (an unspecific MRP inhibitor). Elacridar, at a concentration known to inhibit P-glycoprotein and breast cancer resistance protein (BCRP), only slightly increased ciprofloxacin accumulation, with no difference between resistant and wild-type cells. Analysis at the mRNA (real-time PCR) and protein (Western blotting) levels revealed an overexpression of Mrp2 and Mrp4. Mrp4 transcripts, however, were overwhelmingly predominant (45% [wild-type cells] to 95% [ciprofloxacin-resistant cells] of all Mrp transcripts tested [Mrp1 to Mrp7]). Silencing of Mrp2 and Mrp4 with specific small interfering RNAs showed that only Mrp4 is involved in ciprofloxacin transport in both ciprofloxacin-resistant and wild-type cells. The study therefore identifies Mrp4 as the most likely transporter of ciprofloxacin in murine macrophages but leaves open a possible common upregulation mechanism for both Mrp4 and Mrp2 upon chronic exposure of eukaryotic cells to this widely used antibiotic.

* Corresponding author. Mailing address: Unité de Pharmacologie Cellulaire et Moléculaire, UCL 7370 Avenue Mounier 73, B-1200 Brussels, Belgium. Phone: 32-2-764-73-78. Fax: 32-2-764-73-73. E-mail: francoise.vanbambeke{at}uclouvain.be

{triangledown} Published ahead of print on 23 March 2009.

{dagger} Present address: Ludwig Institute for Cancer Research, Signal Transduction Unit, B-1200 Brussels, Belgium.

Antimicrobial Agents and Chemotherapy, June 2009, p. 2410-2416, Vol. 53, No. 6
0066-4804/09/$08.00+0     doi:10.1128/AAC.01428-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»