Mrp1 Localization and Function in Cardiac Mitochondria after Doxorubicin

Abstract

Multidrug resistance-associated protein 1 (Mrp1; Abcc1) is expressed in sarcolemma of murine heart, where it probably protects the cardiomyocyte by mediating efflux of endo-and xenobiotics. We used doxorubicin (DOX), a chemotherapeutic drug known to induce oxidative stress and thereby cardiac injury, as a model cardiotoxic compound and observed changes in the Mrp1 expression pattern in cardiac tissue of DOX-versus saline-treated mice. Confocal immunofluorescent and immunogold electron microscopy, together with subcellular fractionation followed by immunoblot analyses and transport measurements, localized functional Mrp1 to mitochondria after DOX. Expressions of Mrp1 in heart homogenate, sarcolemma, and submitochondrial particles (SMP) were increased 1.6-, 2-, and 3-fold, respectively, at 24 h after DOX. Mitochondrial Mrp1 expression was markedly increased 72 h after DOX, whereas transport of Mrp1 substrates in SMP was maximal at 24 h. ATP-dependent transport in SMP occurred into an osmotically sensitive space and was inhibited by the anti-MRP1 antibody QCRL3. Adduction of a 190-kDa protein with the reactive lipid peroxidation product 4-hydroxy-2-nonenal (HNE) was detected in SMP and was maximal at 72 h after DOX; immunoprecipitation confirmed Mrp1-HNE adduction. In vitro, HNE (10 M) inhibited mitochondrial respiration and transport activity in SMP, suggesting that Mrp1 is adversely affected by oxidative stress. These data demonstrate that after DOX, functional Mrp1 is detected in mitochondria in addition to that in sarcolemma; however, adduction with HNE inhibits Mrp1 activity. Mrp1 may serve to protect the heart by mediating the efflux of toxic products of oxidative stress from mitochondria and cardiomyocytes.

Sulforaphane protects the heart from doxorubicin-induced toxicity

“…DOX treatment enhances production of the highly reactive lipid peroxidation product HNE in cardiac tissue [65, 66] and forms 4-HNE-protein adducts after interaction with lysine, histidine, and cysteine residues of proteins and peptides. 4-HNE-protein adducts modify protein functions and keep accumulating at high levels in tissues under oxidative/electrophilic stress [3].…”

Differential Activation of Cultured Neonatal Cardiomyocytes by Plasmalemmal Versus Intracellular G Protein-coupled Receptor 55

“…Rather, after its intracellular synthesis by the phospholipase A2, LPI is pumped out of the cell via the multidrug resistance-associated protein 1 (Mrp1/ABCC1) (7). Mrp1 is also expressed in the sarcolemma of rodent heart (66,67).…”

Xenobiotic, Bile Acid, and Cholesterol Transporters: Function and Regulation

“…Mrp1 is expressed in sarcolemmal membranes and the mitochondria of the mouse heart (Jungsuwadee et al, 2006(Jungsuwadee et al, , 2009. Early work by Ishikawa et al (1986Ishikawa et al ( , 1989 demonstrated the ATP-dependent transport of leukotriene C 4 and the glutathione conjugate of 4-hydroxynonenal in the heart via a glutathione S-conjugate transporter later identified as Mrp1.…”

“…A critical role for Mrp1 in angiotensin II-induced hypertension may be via regulation of intracellular thiol concentrations . More recently, it has been suggested that Mrp1 protects the murine heart from doxorubicin-induced cardiotoxicity (Jungsuwadee et al, 2006(Jungsuwadee et al, , 2009.…”