The Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan.
Life Sci. 2011 Aug 15;89(7-8):282-7. doi: 10.1016/j.lfs.2011.06.023. Epub 2011 Jul 7.
Multidrug resistance protein 1 (MDR1) and multidrug resistance-associated protein 1 (MRP1) are ATP-binding cassette transporters that mediate the efflux of a broad spectrum of substances and xenobiotics from cells in barrier organs. Interestingly, they are expressed in immune cells including some kinds of dendritic cells (DCs). In the present study, the expressions and activities of MDR1 and MRP1 in mouse lung DCs (LDCs) were investigated.
We purified LDCs comprising ~98% MHC-Class II(+)/CD11c(+) cells using magnetic and flow cytometric cell sorting. The highly purified LDCs expressed MDR1 and MRP1 at both the mRNA and protein levels. The fluorescent probes rhodamine 123 and Fluo-3 were used as substrates in efflux assays to measure the transport activities of MDR1 and MRP1, respectively.
MDR1 blockade by the specific inhibitor verapamil reduced the percentage of rhodamine 123(low) cells in LDCs (from 31.8±6.3% to 11.8±2.8%, p<0.02). MRP1 blockade by the specific inhibitor MK-571 reduced the percentage of Fluo-3(low) cells in LDCs (from 53.8±1.7% to 26.8±6.4%, p<0.03).
These data showed that LDCs exhibited MDR1- and MRP1-mediated efflux activities. MDR1 and MRP1 in LDCs may be involved in protective functions through their efflux activities.
多药耐药蛋白 1（MDR1）和多药耐药相关蛋白 1（MRP1）是 ATP 结合盒转运蛋白，可将多种物质和外源性化合物从屏障器官的细胞中排出。有趣的是，它们在包括某些树突状细胞（DCs）在内的免疫细胞中表达。在本研究中，研究了小鼠肺 DC（LDCs）中 MDR1 和 MRP1 的表达和活性。
我们使用磁性和流式细胞术分选纯化了包含~98% MHC-Class II(+)/CD11c(+)细胞的 LDCs。高度纯化的 LDCs 在 mRNA 和蛋白水平上均表达 MDR1 和 MRP1。荧光探针罗丹明 123 和 Fluo-3 分别用作流出测定中的底物，以测量 MDR1 和 MRP1 的转运活性。
特异性抑制剂维拉帕米阻断 MDR1 可减少 LDC 中罗丹明 123（低）细胞的百分比（从 31.8±6.3%降至 11.8±2.8%，p<0.02）。特异性抑制剂 MK-571 阻断 MRP1 可减少 LDC 中 Fluo-3（低）细胞的百分比（从 53.8±1.7%降至 26.8±6.4%，p<0.03）。
这些数据表明 LDCs 表现出 MDR1 和 MRP1 介导的外排活性。LDCs 中的 MDR1 和 MRP1 可能通过其外排活性参与保护功能。
