QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: dmd.108.022632v1 36/10/2145    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Mishra, J. Articles by Neudeck, B. L. Search for Related Content PubMed PubMed Citation Articles by Mishra, J. Articles by Neudeck, B. L.

Lipopolysaccharide Increases Cell Surface P-glycoprotein That Exhibits Diminished Activity in Intestinal Epithelial Cells

Department of Clinical Pharmacy (J.M., J.L.R., B.L.N.) and Department of Pharmaceutical Sciences (Q.Z., B.L.N.), The University of Tennessee College of Pharmacy, The University of Tennessee, Memphis, Tennessee; and Division of Pharmacy Practice, University of Wisconsin School of Pharmacy, University of Wisconsin, Madison, Wisconsin (J.M., J.M.D.)

Increasingly, it is recognized that commensal microflora regulate epithelial cell processes through the dynamic interaction of pathogen-associated molecular patterns and host pattern recognition receptors such as Toll-like receptor 4 (TLR4). We therefore investigated the effects of bacterial lipopolysaccharide (LPS) on intestinal P-glycoprotein (P-gp) expression and function. Human SW480 (P-gp+/TLR4+) and Caco-2 (P-gp+/TLR4–) cells were treated with medium control or LPS (100 ng/ml) for 24 h prior to study. P-gp function was assessed by measuring the intracellular concentration of rhodamine 123 (Rh123). To confirm P-gp-specific effects, breast cancer resistance protein (BCRP/ABCG2) and multidrug resistance-associated protein 2 (MRP-2/ABCC2) were also analyzed. Treatment of SW480 cells with LPS led to diminished P-gp activity, which could be prevented with polymyxin B (control: 207 ± 16 versus LPS: 402 ± 22 versus LPS + polymyxin B: 238 ± 26 pmoles Rh123/mg protein, p < 0.05 control versus LPS). These effects could be blocked by using polymyxin B and were not seen in the P-gp+/TLR4– Caco-2 cell line (control: 771 ± 28 versus LPS: 775 ± 59 pmoles Rh123/mg protein). Total cellular levels of P-gp did not change in LPS-treated SW480 cells; however, a significant increase in cell surface P-gp was detected. No change in activity, total protein, or apically located MRP-2 was detected following LPS treatment. Sequence analysis confirmed wild-type status of SW480 cells. These data suggest that activation of TLR4 in intestinal epithelial cells leads to an increase in plasma membrane P-gp that demonstrates a diminished capacity to transport substrate.