Expression and function of multidrug resistance protein 1 and multidrug resistance-associated protein 1 in lung dendritic cells from aging mice.

Multidrug resistance protein 1 and multidrug resistance-associated protein 1 are transporters that efflux diverse xenobiotics from cells. We investigated changes in the expression and activity of multidrug resistance protein 1 and multidrug resistance-associated protein 1 in highly purified lung dendritic cells (LDCs) during aging using magnetic and flow cytometric cell sorting. Multidrug resistance protein 1 blockade by the specific inhibitor reduced the percentage of rhodamine 123(low) cells in LDCs from aged mice (54.8% ± 2.6% to 13.2% ± 2.5%, p < .01). The difference in the proportions of rhodamine 123(low) cells in aged LDCs was more apparent than that in LDCs from young mice (p < .05). The multidrug resistance-associated protein 1-specific inhibitor reduced the percentage of Fluo-3(low) cells in aged LDCs (60.8% ± 5.3% to 25.8% ± 7.5%, p < .01). The difference in the proportions of Fluo-3(low) cells in aged LDCs was smaller than that in young LDCs (p < .05). These data showed that LDCs from aged mice exhibited multidrug resistance protein 1- and multidrug resistance-associated protein 1-mediated efflux and that the age-associated changes differed according to transporters.