PT - JOURNAL ARTICLE AU - Jayshree Mishra AU - Qiuye Zhang AU - Jessica L. Rosson AU - John Moran AU - John M. Dopp AU - Brien L. Neudeck TI - Lipopolysaccharide Increases Cell Surface P-glycoprotein That Exhibits Diminished Activity in Intestinal Epithelial Cells AID - 10.1124/dmd.108.022632 DP - 2008 Oct 01 TA - Drug Metabolism and Disposition PG - 2145--2149 VI - 36 IP - 10 4099 - http://dmd.aspetjournals.org/content/36/10/2145.short 4100 - http://dmd.aspetjournals.org/content/36/10/2145.full SO - Drug Metab Dispos2008 Oct 01; 36 AB - 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. The American Society for Pharmacology and Experimental Therapeutics