Analysis of the In Vivo Functions of Mrp3

Belinsky, Martin G.; Dawson, Paul A.; Shchaveleva, Irina; Bain, Lisa J.; Wang, Renxue; Ling, Victor; Chen, Zhe‐Sheng; Grinberg, Alex; Westphal, Heiner; Klein‐Szanto, Andres J.; Lerro, Anthony; Kruh, Gary D.

doi:10.1124/mol.104.010587

Cited by 151 publications

(133 citation statements)

References 43 publications

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“…However, our finding that there is more advanced cholestatic injury in Mrp4Ϫ/Ϫ mice after CBDL emphasizes that neither Mrp3 nor Ost␣-Ost␤ can fully compensate for the absence of Mrp4, even though both are fully capable of transporting bile acid conjugates. 3,36,37,44,45 Mrp2 mRNA levels in wild-type mice were not significantly different from sham-operated controls, which is consistent with earlier reports at 5 and 7-but not 14 -days after CBDL in the mouse. 11,27 However, Mrp2 protein was significantly greater in the Mrp4Ϫ/Ϫ CBDL mice compared with the Mrp4Ϫ/Ϫ sham-operated mice, possibly reflecting an attempt to extrude bile acid conjugates into bile.…”

Section: Discussionsupporting

confidence: 81%

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Mrp4−/− mice have an impaired cytoprotective response in obstructive cholestasis

et al. 2006

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Mrp4 is a member of the multidrug resistance-associated gene family that is expressed on the basolateral membrane of hepatocytes and undergoes adaptive upregulation in response to cholestatic injury or bile acid feeding. However, the relative importance of Mrp4 in a protective adaptive response to cholestatic injury is not known. To address this issue, common bile duct ligation (CBDL) was performed in wild-type and Mrp4؊/؊ mice and animals followed for 7 days. Histological analysis and serum aminotransferase levels revealed more severe liver injury in the absence of Mrp4 expression. Western analyses revealed that Mrp4, but not Mrp3, was significantly increased after CBDL in wild-type mice. Serum bile acid levels were significantly lower in Mrp4؊/؊ mice than in wild-type CBDL mice, whereas serum bilirubin levels were the same, suggesting that Mrp4 was required to effectively extrude bile acids from the cholestatic liver. Mrp3 and Ost␣-Ost␤ were upregulated in Mrp4؊/؊ mice but were unable to compensate for the loss of Mrp4. High-performance liquid chromatography analysis on liver extracts revealed that taurine tetrahydroxy bile acid/beta-muricholic acid ratios were increased twofold in Mrp4؊/؊ mice. In conclusion, hepatic Mrp4 plays a unique and essential protective role in the adaptive response to obstructive cholestatic liver injury. ( M ultidrug resistance-associated protein 4 (MRP4) (ABCC4) is an ATP-dependent organic anion transporter with broad substrate specificity. [1][2][3] It is a member of the ABC transporter superfamily 4 and is expressed in a variety of epithelia, including the basolateral and apical plasma membranes of the liver and kidneys, respectively. 5-7 However, this array of substrates and specific tissue localization have not provided insight into Mrp4 function in vivo.Mrp4 was first suggested to play a role in the adaptive response to the hepatic overload of bile acids following the genetic deletion of farnesoid X receptor (FXR), a bile acid sensor. 8,9 A subsequent study suggested that Mrp4 was not elevated upon feeding the hydrophobic bile acid, lithocholic acid. 10 Despite this finding, other studies have demonstrated that hepatic Mrp4 is upregulated in both rats and mice after bile duct ligation 6,11 and in pediatric patients with progressive familial intrahepatic cholestasis. 12 Recent studies demonstrate that MRP4 functions as an efflux pump for bile acids together with glutathione. 13 Further support for a role for MRP4 in hepatic bile acid overload is the recent demonstration that Mrp4 is upregulated by the constitutive androstane receptor. 14 Constitutive androstane receptor is a member of the nuclear hormone receptor superfamily that is required to elevate serum bile acids during cholestatic injury. 15 Cholestatic injury in mice, rats, and humans can also result in adaptive responses in other basolateral transporters. Examples include Mrp3, which is primarily a bilirubin conjugate transporter and also a constitutive androstane receptor target, 15 and the recently described heterodi...

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Section: Discussionsupporting

confidence: 81%

“…This is exactly opposite to two recent reports where similar studies were performed in CBDL Mrp3Ϫ/Ϫ mice. 36,37 These studies resulted in lower serum levels of bilirubin in the Mrp3Ϫ/Ϫ mice, whereas serum bile acid levels and liver histology were not significantly different from the wild-type CBDL control group.…”

Section: Discussionmentioning

confidence: 99%

Mrp4−/− mice have an impaired cytoprotective response in obstructive cholestasis

et al. 2006

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“…Bile acid conjugates are actively excreted from the hepatocytes at the basolateral surface by multidrug-resistance-associated proteins (e.g., Mrp3, ABCC3) 26,27 and at canalicular membranes by Mrp2 (ABCC2). 28 Immunohistochemistry revealed persistently increased Mrp3 expression in all PEX2 mutants, regardless of age or BA treatment (Fig.…”

Section: Resultsmentioning

confidence: 99%

Bile acid treatment alters hepatic disease and bile acid transport in peroxisome-deficientPEX2Zellweger mice

et al. 2007

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The marked deficiency of peroxisomal organelle assembly in the PEX2 ؊/؊ mouse model for Zellweger syndrome provides a unique opportunity to developmentally and biochemically characterize hepatic disease progression and bile acid products. The postnatal survival of homozygous mutants enabled us to evaluate the response to bile acid replenishment in this disease state. PEX2 mutant liver has severe but transient intrahepatic cholestasis that abates in the early postnatal period and progresses to steatohepatitis by postnatal day 36. We confirmed the expected reduction of mature C24 bile acids, accumulation of C27-bile acid intermediates, and low total bile acid level in liver and bile from these mutant mice. Treating the PEX2 ؊/؊ mice with bile acids prolonged postnatal survival, alleviated intrahepatic cholestasis and intestinal malabsorption, reduced C27-bile acid intermediate production, and prevented older mutants from developing severe steatohepatitis. However, this therapy exacerbated the degree of hepatic steatosis and worsened the already severe mitochondrial and cellular damage in peroxisome-deficient liver. Both untreated and bile acid-fed PEX2 ؊/؊ mice accumulated high levels of predominantly unconjugated bile acids in plasma because of altered expression of hepatocyte bile acid transporters. Significant amounts of unconjugated bile acids were also found in the liver and bile of PEX2 mutants, indicating a generalized defect in bile acid conjugation. Conclusion: Peroxisome deficiency widely disturbs bile acid homeostasis and hepatic functioning in mice, and the high sensitivity of the peroxisome-deficient liver to bile acid toxicity limits the effectiveness of bile acid therapy for preventing hepatic disease. (HEPATOLOGY 2007;45:982-997.)

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“…It was proposed to have a role in the enterohepatic circulation of bile salts in the rat as the transporter for bile salts from the enterocytes into blood (Hirohashi et al, 2000). However, Abcc3-deficient mice showed no problem in vectorial transport of bile salts from the intestine to blood (Belinsky et al, 2005;Zelcer et al, 2006). In contrast, Abcc3 could play a direct role in basolateral transport of drugs and their conjugates and, as a consequence, an indirect role in the enterohepatic circulation of these drugs.…”

Section: Discussionmentioning

confidence: 84%

“…In contrast, Abcc3 could play a direct role in basolateral transport of drugs and their conjugates and, as a consequence, an indirect role in the enterohepatic circulation of these drugs. ABCC3/Abcc3 is able to transport glucuronate conjugates of compounds such as bilirubin, acetaminophen, and taurohyodeoxycholate (Belinsky et al, 2005;Manautou et al, 2005;Zelcer et al, 2006). In this respect ezetimibe is an attractive model drug for Abcc3 function because it is conjugated in the intestine with glucuronic acid, and it undergoes extensive enterohepatic circulation.…”

Section: Discussionmentioning

confidence: 99%

Complex Pharmacokinetic Behavior of Ezetimibe Depends on Abcc2, Abcc3, and Abcg2

Waart¹,

Vlaming²,

Kunne³

et al. 2009

Drug Metab Dispos

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ABSTRACT:Ezetimibe lowers plasma cholesterol levels by inhibiting the uptake of cholesterol in the intestine. Because of the extensive enterohepatic circulation of ezetimibe, relatively low doses are required to be effective. In blood and bile the majority of ezetimibe is present as a glucuronide conjugate, which is formed in the enterocyte. Presently, it is not clear which mechanisms are responsible for this efficient enterohepatic circulation. Abcc2, Abcc3, and Abcg2 are ATP-binding cassette (ABC) transporters that are expressed in both liver and intestine and are capable of transporting glucuronidated compounds. The aim of this study was to investigate the contribution of these transporters in the enterohepatic cycling of ezetimibe glucuronide (Ez-gluc). Transport studies were performed in plasma membrane vesicles from ABCC2-, ABCC3-, and ABCG2-expressing Sf21 insect cells. Furthermore, intestinal explants from wild-type and Abcc3(؊/؊) mice were used to study vectorial transport in a Ussing chamber setup. Finally, biliary excretion of Ez-gluc was measured in vivo after duodenal delivery of ezetimibe in wild-type, Abcc3(؊/؊), Abcc2(؊/؊), Abcg2(؊/؊), and Abcg2(؊/؊)/Abcc2(؊/؊) mice. ABCC3-, ABCC2-, and ABCG2-mediated transport was dose dependently inhibited by Ez-gluc. In the Ussing chamber Ez-gluc recovered from the basolateral side was significantly reduced in duodenal (2.2%), in jejunal (23%), and in ileal (23%) tissue of Abcc3(؊/؊) mice compared with that in tissues of wild-type mice. Biliary excretion of Ez-gluc was significantly reduced in Abcc3(؊/؊) (34%), Abcc2(؊/؊) (56%), and Abcg2(؊/؊)/ Abcc2(؊/؊) (2.5%) compared with that in wild-type mice. These data demonstrate that the enterohepatic circulation of Ez-gluc strongly depends on the joint function of Abcc3, Abcc2, and Abcg2.

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Analysis of the In Vivo Functions of Mrp3

Cited by 151 publications

References 43 publications

Mrp4−/− mice have an impaired cytoprotective response in obstructive cholestasis

Mrp4−/− mice have an impaired cytoprotective response in obstructive cholestasis

Bile acid treatment alters hepatic disease and bile acid transport in peroxisome-deficientPEX2Zellweger mice

Complex Pharmacokinetic Behavior of Ezetimibe Depends on Abcc2, Abcc3, and Abcg2

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