Proteome studies on liver tissue in a phenobarbital-induced rat model

Wu, Qian; Zhang, Yonghe; Zhao, Xin; Shi, Wan-Lu; Pu, Xiaoping

doi:10.1016/j.ejphar.2011.09.161

Cited by 6 publications

(5 citation statements)

References 48 publications

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“…QA causes CNS damage by activating NMDA receptors (Stone and Perkins, 1981), partly by producing mitochondrial dysfunction (Bordelon et al, 1997) and partly by increasing free-radical generation (Behan et al, 1999). Additionally, a role for P450-mediated metabolic induction of KA and QA has been reported (DiNatale et al, 2010; Wu et al, 2011). P450 enzymes are found to be specifically upregulated in the BBB of multiple drug resistant epileptics (Ghosh et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

A pro-convulsive carbamazepine metabolite: Quinolinic acid in drug resistant epileptic human brain

Ghosh¹,

Marchi²,

Hossain³

et al. 2012

Neurobiology of Disease

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Drugs and their metabolites often produce undesirable effects. These may be due to a number of mechanisms, including biotransformation by P450 enzymes which are not exclusively expressed by hepatocytes but also by endothelial cells in brain from epileptics. The possibility thus exists that the potency of systemically administered central nervous system therapeutics can be modulated by a metabolic blood–brain barrier (BBB). Surgical brain specimens and blood samples (ex vivo) were obtained from drug-resistant epileptic subjects receiving the antiepileptic drug carbamazepine prior to temporal lobectomies. An in vitro blood–brain barrier model was then established using primary cell culture derived from the same brain specimens. The pattern of carbamazepine (CBZ) metabolism was evaluated in vitro and ex vivo using high performance liquid chromatography–mass spectroscopy. Accelerated mass spectroscopy was used to identify 14C metabolites deriving from the parent 14C-carbamazepine. Under our experimental conditions carbamazepine levels could not be detected in drug resistant epileptic brain ex situ; low levels of carbamazepine were detected in the brain side of the in vitro BBB established with endothelial cells derived from the same patients. Four carbamazepine-derived fractions were detected in brain samples in vitro and ex vivo. HPLC-accelerated mass spectroscopy confirmed that these signals derived from 14C-carbamazepine administered as parental drug. Carbamazepine 10, 11 epoxide (CBZ-EPO) and 10, 11-dihydro-10, 11-dihydrooxy-carbamazepine (DiOH-CBZ) were also detected in the fractions analyzed. 14C-enriched fractions were subsequently analyzed by mass spectrometry to reveal micromolar concentrations of quinolinic acid (QA). Remarkably, the disappearance of carbamazepine-epoxide (at a rate of 5% per hour) was comparable to the rate of quinolinic acid production (3% per hour). This suggested that quinolinic acid may be a result of carbamazepine metabolism. Quinolinic acid was not detected in the brain of patients who received antiepileptic drugs other than carbamazepine prior to surgery or in brain endothelial cultures obtained from a control patient. Our data suggest that a drug resistant BBB not only impedes drug access to the brain but may also allow the formation of neurotoxic metabolites.

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Section: Discussionmentioning

confidence: 99%

A pro-convulsive carbamazepine metabolite: Quinolinic acid in drug resistant epileptic human brain

Ghosh¹,

Marchi²,

Hossain³

et al. 2012

Neurobiology of Disease

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“…Previous studies have examined the proteomes of liver microsomes from control and PB-treated rats (Galeva and Altermann, 2002) (Wu et al, 2011) (Klepeisz et al, 2013). Similarly, other studies have used bioinformatics to ascertain related cellular pathways in the liver (Peng et al, 2012) and the effects of PB on cellular pathways (Klepeisz et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

“…Initially, it was proposed that PB induced a stress response based on the induction of 78 kDa glucose regulated protein and protein disulfide isomerases A 3 and A 6 (Galeva and Altermann, 2002). Subsequently, mixed changes in glycolysis and increased oxidative stress and proteasomal-mediated protein degradation were proposed based on the observed, PB-related, changes in protein expression (Wu et al, 2011).…”

Section: Effects Of Pb-induction On Cellular Pathways By Ipamentioning

confidence: 99%

Proteomic and Bioinformatics Analysis of Membrane Lipid Domains after Brij 98 Solubilization of Uninduced and Phenobarbital-Induced Rat Liver Microsomes: Defining the Membrane Localization of the P450 Enzyme System

Reed

Guidry

Backes

2022

Drug Metabolism and Disposition

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The proteomes of ordered and disordered lipid microdomains in rat liver microsomes from control and phenobarbital (PB)-treated rats were determined after solubilization with Brij 98 and analyzed by Tandem Mass Tag (TMT)-LC-MS. This allowed characterization of the liver microsomal proteome and the effects of phenobarbital-mediated induction, focusing on quantification of the relative levels of the drug metabolizing enzymes. The microsomal proteome from control rats was represented by 333 (23%) proteins from ordered lipid microdomains, 517 (36%) proteins from disordered lipid domains, and 587 (41%) proteins that uniformly distributed between lipid microdomains. Most enzymes related to drug metabolism were mainly localized in disordered lipid microdomains. However, CYP1A2, multiple forms of CYP2D, and several forms of UDP glucuronosyltransferases (UGT1A1 & UGT1A6) localized to ordered lipid microdomains. Other drug metabolizing enzymes, including several forms of cytochromes P450, were uniformly distributed between the ordered and disordered regions. The redox partners, NADPH-cytochrome P450 reductase and cytochrome b 5 , localized to disordered microdomains. PB induction resulted in only modest changes in protein localization. Less than five proteins were variably associated with the ordered and disordered membrane microdomains in PB and control microsomes. PB-induction was associated with fewer proteins localizing in the disordered membranes, and more being uniformly distributed or localized to ordered domains. Ingenuity Pathway Analysis (IPA) was used to ascertain the effect of PB on cellular pathways, resulting in attenuation of pathways related to energy storage/utilization and overall cellular signaling and an increase in those related to degradative pathways.

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“…For this, P14 male mice with WT or TrxR1-null livers were treated with 25 mg/kg DEN, and at P44, one-half of the mice were switched permanently onto drinking water containing 0.07% phenobarbital (PB) (47,48). Metabolism of PB by hepatocyte-specific cytochrome P450s results in chronic NADPH-dependent ROS generation (49)(50)(51). At harvest (P240), most livers exhibited only few and small tumors, with the exception of TrxR1-null livers that had been under chronic PB stress, which exhibited dramatic cancer ( Fig.…”

Section: Cancer Resistance In Trxr1-null Livers Correlates With Altermentioning

confidence: 99%

TrxR1, Gsr, and oxidative stress determine hepatocellular carcinoma malignancy

McLoughlin

Orlicky

Prigge

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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Thioredoxin reductase-1 (TrxR1)-, glutathione reductase (Gsr)-, and Nrf2 transcription factor-driven antioxidant systems form an integrated network that combats potentially carcinogenic oxidative damage yet also protects cancer cells from oxidative death. Here we show that although unchallenged wild-type (WT), TrxR1-null, or Gsr-null mouse livers exhibited similarly low DNA damage indices, these were 100-fold higher in unchallenged TrxR1/Gsr–double-null livers. Notwithstanding, spontaneous cancer rates remained surprisingly low in TrxR1/Gsr-null livers. All genotypes, including TrxR1/Gsr-null, were susceptible to N-diethylnitrosamine (DEN)-induced liver cancer, indicating that loss of these antioxidant systems did not prevent cancer cell survival. Interestingly, however, following DEN treatment, TrxR1-null livers developed threefold fewer tumors compared with WT livers. Disruption of TrxR1 in a marked subset of DEN-initiated cancer cells had no effect on their subsequent contributions to tumors, suggesting that TrxR1-disruption does not affect cancer progression under normal care, but does decrease the frequency of DEN-induced cancer initiation. Consistent with this idea, TrxR1-null livers showed altered basal and DEN-exposed metabolomic profiles compared with WT livers. To examine how oxidative stress influenced cancer progression, we compared DEN-induced cancer malignancy under chronically low oxidative stress (TrxR1-null, standard care) vs. elevated oxidative stress (TrxR1/Gsr-null livers, standard care or phenobarbital-exposed TrxR1-null livers). In both cases, elevated oxidative stress was correlated with significantly increased malignancy. Finally, although TrxR1-null and TrxR1/Gsr-null livers showed strong Nrf2 activity in noncancerous hepatocytes, there was no correlation between malignancy and Nrf2 expression within tumors across genotypes. We conclude that TrxR1, Gsr, Nrf2, and oxidative stress are major determinants of liver cancer but in a complex, context-dependent manner.

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Proteome studies on liver tissue in a phenobarbital-induced rat model

Cited by 6 publications

References 48 publications

A pro-convulsive carbamazepine metabolite: Quinolinic acid in drug resistant epileptic human brain

A pro-convulsive carbamazepine metabolite: Quinolinic acid in drug resistant epileptic human brain

Proteomic and Bioinformatics Analysis of Membrane Lipid Domains after Brij 98 Solubilization of Uninduced and Phenobarbital-Induced Rat Liver Microsomes: Defining the Membrane Localization of the P450 Enzyme System

TrxR1, Gsr, and oxidative stress determine hepatocellular carcinoma malignancy

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