AIM： To investigate the expression and activity of NAD（P）H quinone oxidoreductase 1 （NQO1） in human liver specimens obtained from patients with liver damage due to acetaminophen （APAP） overdose or primary bilia...AIM： To investigate the expression and activity of NAD（P）H quinone oxidoreductase 1 （NQO1） in human liver specimens obtained from patients with liver damage due to acetaminophen （APAP） overdose or primary biliary cirrhosis （PBC）. METHODS： NQOt activity was determined in cytosol from normal, APAP and PBC liver specimens. Western blot and immunohistochemical staining were used to determine patterns of NQO1 expression using a specific antibody against NQO1. RESULTS： NQO1 protein was very low in normal human livers. In both APAP and PBC livers, there was strong induction of NQO1 protein levels on Western blot. Correspondingly, significant up-regulation of enzyme activity （16- and 22-fold, P〈0.05） was also observed in APAP and PBC livers, respectively. Immunohistochemical analysis highlighted injury-specific patterns of NQO1 staining in both APAP and PBC livers. CONCLUSION： These data demonstrate that NQO1 protein and activity are markedly induced in human livers during both APAP overdose and PBC. Up-regulation of this cytoprotective enzyme may represent an adaptive stress response to limit further disease progression by detoxifying reactive species.展开更多
Bile acids(BAs) are amphipathic molecules important for metabolism of cholesterol,absorption of lipids and lipid soluble vitamins,bile flow,and regulation of gut microbiome.There are over 30 different BA species known...Bile acids(BAs) are amphipathic molecules important for metabolism of cholesterol,absorption of lipids and lipid soluble vitamins,bile flow,and regulation of gut microbiome.There are over 30 different BA species known to exist in humans and mice,which are endogenous modulators of at least 6 different membrane or nuclear receptors.This diversity of ligands and receptors play important roles in health and disease;however,the full functions of each individual BA in vivo remain unclear.We generated a mouse model lacking the initiating enzymes,CYP7 A1 and CYP27 A1,in the two main pathways of BA synthesis.Because females are more susceptible to BA related diseases,such as intrahepatic cholestasis of pregnancy,we expanded this model into female mice.The null mice of Cyp7 a1 and Cyp27 a1 were crossbred to create double knockout(DKO) mice.BA concentrations in female DKO mice had reductions in serum(63%),liver(83%),gallbladder(94%),and small intestine(85%),as compared to WT mice.Despite low BA levels,DKO mice had a similar expression pattern to that of WT mice for genes involved in BA regulation,synthesis,conjugation,and transport.Additionally,through treatment with a synthetic FXR agonist,GW4064,female DKO mice responded to FXR activation similarly to WT mice.展开更多
Disease-mediated alterations to drug disposition constitute a significant source of adverse drug reactions.Cisplatin(CDDP)elicits nephrotoxicity due to exposure in proximal tubule cells during renal secretion.Alterati...Disease-mediated alterations to drug disposition constitute a significant source of adverse drug reactions.Cisplatin(CDDP)elicits nephrotoxicity due to exposure in proximal tubule cells during renal secretion.Alterations to renal drug transporter expression have been discovered during nonalcoholic steatohepatitis(NASH),however,associated changes to substrate toxicity is unknown.To test this,a methionine-and choline-deficient diet-induced rat model was used to evaluate NASH-associated changes to CDDP pharmacokinetics,transporter expression,and toxicity.NASH rats administered CDDP(6 mg/kg,i.p.)displayed 20%less nephrotoxicity than healthy rats.Likewise,CDDP renal clearance decreased in NASH rats from 7.39 to 3.83 mL/min,renal secretion decreased from 6.23 to 2.80 mL/min,and renal CDDP accumulation decreased by 15%,relative to healthy rats.Renal copper transporter-1 expression decreased,and organic cation transporter-2 and ATPase copper transporting protein-7 b increased slightly,reducing CDDP secretion.Hepatic CDDP accumulation increased 250%in NASH rats relative to healthy rats.Hepatic organic cation transporter-1 induction and multidrug and toxin extrusion protein-1 and multidrug resistance-associated protein-4 reduction may contribute to hepatic CDDP sequestration in NASH rats,although no drug-related toxicity was observed.These data provide a link between NASH-induced hepatic and renal transporter expression changes and CDDP renal clearance,which may alter nephrotoxicity.展开更多
Hepatocyte hopping is the hepatocyte-to-sinusoid-to-hepatocyte shuttling that increases the efficiency of hepatic elimination of xenobiotics. This phenomenon is mediated via efflux of hepatic metabolites by Mrp3 and r...Hepatocyte hopping is the hepatocyte-to-sinusoid-to-hepatocyte shuttling that increases the efficiency of hepatic elimination of xenobiotics. This phenomenon is mediated via efflux of hepatic metabolites by Mrp3 and reuptake by Oatp transporters in sequential hepatocytes until eventual biliary efflux by Mrp2. Sorafenib-glucuronide (SFB-G), the major metabolite of sorafenib (SFB), undergoes hepatocyte hopping, leading to efficient biliary elimination. Nonalcoholic steatohepatitis (NASH) alters the functioning of transporters involved in hepatocyte hopping. The purpose of this study was to quantify the effect of NASH on the three drug disposition processes of hepatocyte hopping. Male FVB and C57BL/6 wild-type (WT), Oatp1a/1b cluster knockout (O^(−/−)), and Mrp2 knockout (Mrp2^(−/−)) mice were fed a methionine and choline deficient (MCD) diet to induce NASH. Mice were administered 10 mg/kg SFB via oral gavage and concentrations of SFB and SFB-G in plasma quantified using liquid-chromatography tandem mass spectrometry. Compared to WT, plasma area under the concentration-time curve (AUC) of SFB-G increased by 108-fold in the O^(-/--)C group and by 345-fold in the Mrp2^(-/--)C group. In the WT-NASH group, up-regulation of Mrp3 and decreased Mrp2 function, along with reduced Oatp uptake, elevated SFB-G AUC by 165-fold. SFB-G AUC in the O^(-/--)NASH group increased by 108-fold compared to WT-C (3.2-fold compared to O^(-/--)C). SFB-G AUC in the Mrp2^(-/--)NASH group increased by 450-fold (1.2-fold compared to Mrp2^(-/--)C). Taken together, the mislocalization of Mrp2 in NASH is a major contributor to the decrease in SFB-G biliary efflux, but decreased Oatp uptake and enhanced sinusoidal efflux also limit the contribution of downstream hepatocytes, resulting in plasma retention that recapitulates the altered pharmacokinetics observed in human NASH.展开更多
文摘AIM： To investigate the expression and activity of NAD（P）H quinone oxidoreductase 1 （NQO1） in human liver specimens obtained from patients with liver damage due to acetaminophen （APAP） overdose or primary biliary cirrhosis （PBC）. METHODS： NQOt activity was determined in cytosol from normal, APAP and PBC liver specimens. Western blot and immunohistochemical staining were used to determine patterns of NQO1 expression using a specific antibody against NQO1. RESULTS： NQO1 protein was very low in normal human livers. In both APAP and PBC livers, there was strong induction of NQO1 protein levels on Western blot. Correspondingly, significant up-regulation of enzyme activity （16- and 22-fold, P〈0.05） was also observed in APAP and PBC livers, respectively. Immunohistochemical analysis highlighted injury-specific patterns of NQO1 staining in both APAP and PBC livers. CONCLUSION： These data demonstrate that NQO1 protein and activity are markedly induced in human livers during both APAP overdose and PBC. Up-regulation of this cytoprotective enzyme may represent an adaptive stress response to limit further disease progression by detoxifying reactive species.
基金supported by the National Institutes of Health(NIHR01GM104037,NIH-R21ES029258,NIH-T32ES007148,VA-BX002741,NIH-F31DK122725,RCLR graduate student award fund,USA)。
文摘Bile acids(BAs) are amphipathic molecules important for metabolism of cholesterol,absorption of lipids and lipid soluble vitamins,bile flow,and regulation of gut microbiome.There are over 30 different BA species known to exist in humans and mice,which are endogenous modulators of at least 6 different membrane or nuclear receptors.This diversity of ligands and receptors play important roles in health and disease;however,the full functions of each individual BA in vivo remain unclear.We generated a mouse model lacking the initiating enzymes,CYP7 A1 and CYP27 A1,in the two main pathways of BA synthesis.Because females are more susceptible to BA related diseases,such as intrahepatic cholestasis of pregnancy,we expanded this model into female mice.The null mice of Cyp7 a1 and Cyp27 a1 were crossbred to create double knockout(DKO) mice.BA concentrations in female DKO mice had reductions in serum(63%),liver(83%),gallbladder(94%),and small intestine(85%),as compared to WT mice.Despite low BA levels,DKO mice had a similar expression pattern to that of WT mice for genes involved in BA regulation,synthesis,conjugation,and transport.Additionally,through treatment with a synthetic FXR agonist,GW4064,female DKO mice responded to FXR activation similarly to WT mice.
基金supported by the National Institutes of Health(R01ES028668,P30ES006694,and T32ES007091,USA)。
文摘Disease-mediated alterations to drug disposition constitute a significant source of adverse drug reactions.Cisplatin(CDDP)elicits nephrotoxicity due to exposure in proximal tubule cells during renal secretion.Alterations to renal drug transporter expression have been discovered during nonalcoholic steatohepatitis(NASH),however,associated changes to substrate toxicity is unknown.To test this,a methionine-and choline-deficient diet-induced rat model was used to evaluate NASH-associated changes to CDDP pharmacokinetics,transporter expression,and toxicity.NASH rats administered CDDP(6 mg/kg,i.p.)displayed 20%less nephrotoxicity than healthy rats.Likewise,CDDP renal clearance decreased in NASH rats from 7.39 to 3.83 mL/min,renal secretion decreased from 6.23 to 2.80 mL/min,and renal CDDP accumulation decreased by 15%,relative to healthy rats.Renal copper transporter-1 expression decreased,and organic cation transporter-2 and ATPase copper transporting protein-7 b increased slightly,reducing CDDP secretion.Hepatic CDDP accumulation increased 250%in NASH rats relative to healthy rats.Hepatic organic cation transporter-1 induction and multidrug and toxin extrusion protein-1 and multidrug resistance-associated protein-4 reduction may contribute to hepatic CDDP sequestration in NASH rats,although no drug-related toxicity was observed.These data provide a link between NASH-induced hepatic and renal transporter expression changes and CDDP renal clearance,which may alter nephrotoxicity.
基金by National Institute of General Medical Sciences grant(GM123643,USA)National Institute of Environmental Health Sciences grants(T32ES007148,ES028668,ES006694,and ES007091,USA).
文摘Hepatocyte hopping is the hepatocyte-to-sinusoid-to-hepatocyte shuttling that increases the efficiency of hepatic elimination of xenobiotics. This phenomenon is mediated via efflux of hepatic metabolites by Mrp3 and reuptake by Oatp transporters in sequential hepatocytes until eventual biliary efflux by Mrp2. Sorafenib-glucuronide (SFB-G), the major metabolite of sorafenib (SFB), undergoes hepatocyte hopping, leading to efficient biliary elimination. Nonalcoholic steatohepatitis (NASH) alters the functioning of transporters involved in hepatocyte hopping. The purpose of this study was to quantify the effect of NASH on the three drug disposition processes of hepatocyte hopping. Male FVB and C57BL/6 wild-type (WT), Oatp1a/1b cluster knockout (O^(−/−)), and Mrp2 knockout (Mrp2^(−/−)) mice were fed a methionine and choline deficient (MCD) diet to induce NASH. Mice were administered 10 mg/kg SFB via oral gavage and concentrations of SFB and SFB-G in plasma quantified using liquid-chromatography tandem mass spectrometry. Compared to WT, plasma area under the concentration-time curve (AUC) of SFB-G increased by 108-fold in the O^(-/--)C group and by 345-fold in the Mrp2^(-/--)C group. In the WT-NASH group, up-regulation of Mrp3 and decreased Mrp2 function, along with reduced Oatp uptake, elevated SFB-G AUC by 165-fold. SFB-G AUC in the O^(-/--)NASH group increased by 108-fold compared to WT-C (3.2-fold compared to O^(-/--)C). SFB-G AUC in the Mrp2^(-/--)NASH group increased by 450-fold (1.2-fold compared to Mrp2^(-/--)C). Taken together, the mislocalization of Mrp2 in NASH is a major contributor to the decrease in SFB-G biliary efflux, but decreased Oatp uptake and enhanced sinusoidal efflux also limit the contribution of downstream hepatocytes, resulting in plasma retention that recapitulates the altered pharmacokinetics observed in human NASH.
