Modulation of Nitrated Lipid Signaling by Multidrug Resistance Protein 1 (MRP1): Glutathione Conjugation and MRP1-Mediated Efflux Inhibit Nitrolinoleic Acid-Induced, PPAR
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- 作者：Richard L. Alexander ; Darcy J. P. Bates ; Marcus W. Wright ; S. Bruce King ; and Charles S. Morrow
- 刊名：Biochemistry
- 出版年：2006
- 出版时间：June 27, 2006
- 年：2006
- 卷：45
- 期：25
- 页码：7889 - 7896
- 全文大小：139K
- 年卷期：v.45,no.25(June 27, 2006)
- ISSN：1520-4995
文摘
Recent data has shown that nitrolinoleic acid (LNO2), an electrophilic derivative of linoleicacid, has several important bioactivities including antiinflammatory, antiplatelet, vasorelaxation, and-asa novel potent ligand of PPAR
-transcription regulating activities. Moreover, LNO2 is formed in abundancein vivo at levels sufficient to mediate these bioactivities. In order to investigate the role of glutathioneconjugation and MRP1-mediated efflux in the regulation of PPAR-dependent LNO2 signaling, regioisomersof LNO2 were synthesized and characterized. Analysis by 1D and 2D 1H and 13C NMR revealed that theLNO2 preparation consisted of four, rather than two, nitrated regioisomers in approximately equalabundance. At physiologic pH and intracellular glutathione levels, LNO2 was rapidly and quantitativelyconverted to glutathione conjugates (LNO2-SG) via Michael addition. MRP1 mediated efficient ATP-dependent transport of LNO2-SG. Using a PPRE-containing reporter gene transiently transfected intoMRP-poor MCF7/WT cells, we verified that the LNO2 mixture was a potent activator of PPAR-dependenttranscription. However, expression of MRP1 in the stably transduced MCF7 derivative, MCF7/MRP1-10, resulted in strong inhibition of LNO2-induced transcription activation. Taken together, these resultssuggest that glutathione conjugation and MRP1-mediated conjugate transport can attenuate LNO2 bioactivityand thereby play important roles in the regulation of cellular signaling by LNO2.
-transcription regulating activities. Moreover, LNO2 is formed in abundancein vivo at levels sufficient to mediate these bioactivities. In order to investigate the role of glutathioneconjugation and MRP1-mediated efflux in the regulation of PPAR-dependent LNO2 signaling, regioisomersof LNO2 were synthesized and characterized. Analysis by 1D and 2D 1H and 13C NMR revealed that theLNO2 preparation consisted of four, rather than two, nitrated regioisomers in approximately equalabundance. At physiologic pH and intracellular glutathione levels, LNO2 was rapidly and quantitativelyconverted to glutathione conjugates (LNO2-SG) via Michael addition. MRP1 mediated efficient ATP-dependent transport of LNO2-SG. Using a PPRE-containing reporter gene transiently transfected intoMRP-poor MCF7/WT cells, we verified that the LNO2 mixture was a potent activator of PPAR-dependenttranscription. However, expression of MRP1 in the stably transduced MCF7 derivative, MCF7/MRP1-10, resulted in strong inhibition of LNO2-induced transcription activation. Taken together, these resultssuggest that glutathione conjugation and MRP1-mediated conjugate transport can attenuate LNO2 bioactivityand thereby play important roles in the regulation of cellular signaling by LNO2.