Rat Liver Protein Research Articles

Unified Synthesis of 1,2-Oxy-aminoarenes via a Bio-inspired Phenol-Amine Coupling

Summary 1,2-Aminophenols and their related nitrogen-containing heterocycles are ubiquitous in medicine, agriculture, and materials science. Here, we describe a bio-inspired and unified approach for their synthesis through a direct, catalytic aerobic coupling of phenols and amines. Key to the formation of the aromatic C–N bond is a facile condensation between the amine and an ortho -quinone, which triggers redox isomerization to an ortho -iminophenol before a series of downstream events. We discuss the factors that govern regioselectivity during aerobic ortho -oxygenation of the phenol and condensation of the amine, and we demonstrate synthetic utility by preparing a structurally diverse family of immunosuppressive heterocycles and the indole alkaloid cephalandole A. Our conditions involve a wide range of simple, un-activated substrates, occur at room temperature with an earth-abundant copper-catalyst and a commercially available diamine ligand, and produce water as the only stoichiometric by-product.

Insulin and diet-induced changes in the ubiquitin-modified proteome of rat liver.

Ubiquitin is a crucial post-translational modification regulating numerous cellular processes, but its role in metabolic disease is not well characterized. In this study, we identified the in vivo ubiquitin-modified proteome in rat liver and determined changes in this ubiquitome under acute insulin stimulation and high-fat and sucrose diet-induced insulin resistance. We identified 1267 ubiquitinated proteins in rat liver across diet and insulin-stimulated conditions, with 882 proteins common to all conditions. KEGG pathway analysis of these proteins identified enrichment of metabolic pathways, TCA cycle, glycolysis/gluconeogenesis, fatty acid metabolism, and carbon metabolism, with similar pathways altered by diet and insulin resistance. Thus, the rat liver ubiquitome is sensitive to diet and insulin stimulation and this is perturbed in insulin resistance.

Accounting for Protein Subcellular Localization: A Compartmental Map of the Rat Liver Proteome

Accurate knowledge of the intracellular location of proteins is important for numerous areas of biomedical research including assessing fidelity of putative protein-protein interactions, modeling cellular processes at a system-wide level and investigating metabolic and disease pathways. Many proteins have not been localized, or have been incompletely localized, partly because most studies do not account for entire subcellular distribution. Thus, proteins are frequently assigned to one organelle whereas a significant fraction may reside elsewhere. As a step toward a comprehensive cellular map, we used subcellular fractionation with classic balance sheet analysis and isobaric labeling/quantitative mass spectrometry to assign locations to >6000 rat liver proteins. We provide quantitative data and error estimates describing the distribution of each protein among the eight major cellular compartments: nucleus, mitochondria, lysosomes, peroxisomes, endoplasmic reticulum, Golgi, plasma membrane and cytosol. Accounting for total intracellular distribution improves quality of organelle assignments and assigns proteins with multiple locations. Protein assignments and supporting data are available online through the Prolocate website (http://prolocate.cabm.rutgers.edu). As an example of the utility of this data set, we have used organelle assignments to help analyze whole exome sequencing data from an infant dying at 6 months of age from a suspected neurodegenerative lysosomal storage disorder of unknown etiology. Sequencing data was prioritized using lists of lysosomal proteins comprising well-established residents of this organelle as well as novel candidates identified in this study. The latter included copper transporter 1, encoded by SLC31A1, which we localized to both the plasma membrane and lysosome. The patient harbors two predicted loss of function mutations in SLC31A1, suggesting that this may represent a heretofore undescribed recessive lysosomal storage disease gene.

The effects of triptolide on the pharmacokinetics of sorafenib in rats and its potential mechanism

Context: Combining sorafenib with triptolide could inhibit tumour growth with greater efficacy than single-agent treatment. However, their herb–drug interaction remains unknown.Objective: This study investigates the herb–drug interaction between triptolide and sorafenib.Materials and methods: The effects of triptolide (10 mg/kg) on the pharmacokinetics of different doses of sorafenib (20, 50 and 100 mg/kg) in rats, and blood samples were collected within 48 h and evaluated using LC-MS/MS. The effects of triptolide on the absorption and metabolism of sorafenib were also investigated using Caco-2 cell monolayer model and rat liver microsome incubation systems.Results: The results showed that the Cmax (low dose: 72.38 ± 8.76 versus 49.15 ± 5.46 ng/mL; medium dose: 178.65 ± 21.05 versus 109.31 ± 14.17 ng/mL; high dose: 332.81 ± 29.38 versus 230.86 ± 9.68 ng/mL) of sorafenib at different doses increased significantly with the pretreatment of triptolide, and while the oral clearance rate of sorafenib decreased. The t1/2 of sorafenib increased significant (p < 0.05) from 9.02 ± 1.16 to 12.17 ± 2.95 h at low dose with the pretreatment of triptolide. Triptolide has little effect on the absorption of sorafenib in Caco-2 cell transwell model. However, triptolide could significantly decrease the intrinsic clearance rate of sorafenib from 51.7 ± 6.37 to 32.4 ± 4.43 μL/min/mg protein in rat liver microsomes.Discussion and conclusions: These results indicated that triptolide could change the pharmacokinetic profiles of sorafenib in rats; these effects might be exerted via decreasing the intrinsic clearance rate of sorafenib in rat liver.

Autoantibodies against CYP-2C19: A Novel Serum Marker in Pediatric De Novo Autoimmune Hepatitis?

Diagnosis of de novo autoimmune hepatitis (AIH) after orthotopic liver transplantation (OLT) is challenging especially in the absence of hyper-γ-globulinemia. Circulating autoantibodies are not sensitive nor specific in de novo AIH but when positive increase the diagnostic probability. We report the discovery of novel liver microsomal (LM) autoantibodies against CYP-2C19 in a 9-year-old boy with “de novo” AIH developed 7 years after OLT. Graft dysfunction presented with hypertransaminasemia (up to 400 IU/L), while serum γ-globulins remained within the normal range for age. Liver histology and response to high dose prednisone (2 mg/kg/day) with the addition of azathioprine therapy further supported the diagnosis of de novo AIH. Autoantibodies investigation by indirect immunofluorescence (IF) on rodent tissues showed a novel staining pattern involving the pericentral liver zone and sparing the renal tissue. Human but not rat liver proteins immunoblotting allowed us to characterize the novel LM antibodies and to identify CYP-2C19 as human antigen. The finding offers insights into the controversial discussion about autoimmunity versus alloreactivity with regard to the pathogenesis of de novo AIH. Correct information on human versus rat tissue antigens tested by methods other than IF for antibodies detection may have significant implications for the correct diagnosis and management of patients followed up after OLT.

Changes in liver proteins of rats fed standard and high-fat and sucrose diets induced by fish omega-3 PUFAs and their combination with grape polyphenols according to quantitative proteomics

This study considered the physiological modulation of liver proteins due to the supplementation with fish oils under two dietary backgrounds: standard or high in fat and sucrose (HFHS), and their combination with grape polyphenols. By using a quantitative proteomics approach, we showed that the capacity of the supplements for regulating proteins depended on the diet; namely, 10 different proteins changed into standard diets, while 45 changed into the HFHS diets and only scarcely proteins were found altered in common. However, in both contexts, fish oils were the main regulatory force, although the addition of polyphenols was able to modulate some fish oils' effects. Moreover, we demonstrated the ability of fish oils and their combination with grape polyphenols in improving biochemical parameters and reducing lipogenesis and glycolysis enzymes, enhancing fatty acid beta-oxidation and insulin signaling and ameliorating endoplasmic reticulum stress and protein oxidation when they are included in an unhealthy diet.

Preparation and application of immobilized enzymatic reactors for consecutive digestion with two enzymes

The bottom up strategy has drawn much attention due to the high accuracy, reliability, and reproducibility in protein identification in which proteins are digested into peptides. However, conventional solution-based digestion and enzymatic reactor with one protease immobilized cannot satisfy high throughput proteolysis of complex samples. Application of consecutive hydrolysis by enzymatic reactor can be a new strategy for high throughput proteolysis of complex samples by adjusting immobilization amount of the enzymes, enzyme ratio, as well as hydrolysis order of two enzymes. In this work, we propose immobilized enzymatic reactor for consecutive digestion with two enzymes by combining two enzyme reactors with trypsin and chymotrypsin immobilized, respectively. Each reactor was prepared individually by immobilizing only one protease (trypsin or chymotrypsin) to hybrid monolith with SBA-15 particles embedded. Proteolysis conditions including hydrolysis order and trypsin to chymotrypsin ratio etc. were studied using standard proteins. Best digestion performance was obtained when the proteins were digested by trypsin first with trypsin to chymotrypsin ratio of 1:1. When applying them to digestion of rat liver proteins, total 1651 proteins and 11011 peptides were identified by combining four enzymolysis strategies with two enzymes including proteolytic digestion in two consecutive enzymatic reactors, synergy enzymolysis with two enzymes in one immobilized enzymatic reactor and consecutive hydrolysis with two enzymes in-solution digestion respectively, in which consecutive enzymolysis in enzymatic reactors gave the best results with 1091 proteins and 5071 peptides identified. The reactors showed good digestion capability for proteins with different hydrophobicity and molecular weights, and will play an important role in high efficient and high throughput proteomics research.

Ultrastructural localization of the ROMK potassium channel in rat liver and heart

The intracellular localization and distribution of the ROMK protein in rat liver and heart was studied by the electron microscopy of ultrathin sections using the antibodies against the ROMK channel protein, one of the contenders for the role of mitochondrial ATP-dependent potassium channel. In rat heart and liver tissues, the ROMK protein is localized on the membranes of mitochondrial cristae but differently distributed in hepatocytes and cardiomyocytes. In hepatocytes, colloidal gold particles were rather evenly distributed on the membranes of mitochondrial cristae. In cardiomyocytes, the number of granules was considerably lower than in hepatocytes, and they were also localized on the membranes of mitochondrial cristae and confined only by the center of these organelles.

Changing the content of histone proteins and heat-shock proteins in the blood and liver of rats after the single and repeated administration of nanocluster iron-molybdenum polyoxometalates

The effect of nanocluster iron-molybdenum polyoxometallates (POMs) on the content of histone proteins and heat shock proteins in rat blood and liver after single and repeated administration had been investigated. It is found that the introduction of POMs was not accompanied by a decrease in the number of histone proteins in blood lymphocytes, which may indicate a lack of gene expression of proinflammatory factors. An increase in the content of the heat shock protein Hsp60 and Hsp70 in the liver is revealed, and the degree of increase depended on the nanoparticles exposition. The assumptions about the absence of a lymphocytes proinflammatory phenotype and the heat shock proteins protective effect are confirmed with the continuation of normal functional-state liver parameters during all periods of polyoxometalates exposure.

Proteomics approach to analyze protein profiling related with ADME/Tox in rat treated with Scutellariae radix and Coptidis rhizoma as well as their compatibility

Ethnopharmacological relevanceScutellariae radix (Scutellaria baicalensis Georgi) and Coptidis rhizoma (Coptis chinensis Franch), known as traditional Chinese medicine (TCM), have been widely used with the effects of suppressing fever, dispelling dampness, purging fire and removing toxicosis. Owing to their unimaginable complexity, it is difficult to understand their pharmacokinetic properties in detail. The aim of this study was to develop an optimal proteomics approach to analyze the protein profiling related with ADME/Tox in rat liver treated with S. radix and C. rhizoma as well as their compatibility. Materials and methodsMale rats were respectively administered the extracts of S. radix, C. rhizoma and their mixture for 7 days, and their liver tissue samples were prepared for the comparative proteomic analysis. The significantly differentially expressed proteins between the experimental groups and the control group were found and identified by 2-DE and MALDI-TOF-MS analyses. To validate the proteomic analysis results, glutathion peroxidase, catalase and betaine homocysteine methyl transferase were selected and confirmed by western blotting. ResultsSeventy eight significantly differentially expressed proteins between the experimental groups and the control group were found and identified. By querying the relational databases, the identified differentially expressed proteins were summarized and classified into three groups, phase I drug metabolic enzymes, phase II drug metabolic enzymes and the rest proteins which mainly involve in energy metabolism, signal transduction and cytoskeleton. These proteins involved in ADME/Tox may be the targets for metabolic studies or markers for toxicity. ConclusionsOur findings indicated S. radix and C. rhizoma as well as their compatibility can assuredly influence the expression of the proteins in rat liver. After administration, the majority of these expressions presented a downward trend, which may be closely related to the pharmacological properties of the medicine. The method in this study may open up a new road for the complementary tests for ADME/Tox properties of S. radix and C. rhizoma as well as their compatibility.

Investigation of bi-enzymatic reactor based on hybrid monolith with nanoparticles embedded and its proteolytic characteristics

The bottom-up strategy of proteomic profiling study based on mass spectrometer (MS) has drawn high attention. However, conventional solution-based digestion could not satisfy the demands of highly efficient and complete high throughput proteolysis of complex samples. We proposed a novel bi-enzymatic reactor by immobilizing two different enzymes (trypsin/chymotrypsin) onto a mixed support of hybrid organic–inorganic monolith with SBA-15 nanoparticles embedded. Typsin and chymotrypsin were crossly immobilized onto the mixed support by covalent bonding onto the monolith with glutaraldehyde as bridge reagent and chelation via copper ion onto the nanoparticles, respectively. Compared with single enzymatic reactors, the bi-enzymatic reactor improved the overall functional analysis of membrane proteins of rat liver by doubling the number of identified peptides (from 1184/1010 with trypsin/chymotrypsin enzymatic reactors to 2891 with bi-enzymatic reactor), which led to more proteins identified with deep coverage (from 452/336 to 620); the efficiency of the bi-enzymatic reactor is also better than that of solution-based tandem digestion, greatly shorting the digestion time from 24h to 50s. Moreover, more transmembrane proteins were identified by bi-enzymatic reactor (106) compared with solution-based tandem digestion (95) with the same two enzymes and enzymatic reactors with single enzyme immobilized (75 with trypsin and 66 with chymotrypsin). The proteolytic characteristics of the bi-enzymatic reactors were evaluated by applying them to digestion of rat liver proteins. The reactors showed good digestion capability for proteins with different hydrophobicity and molecular weight.

Cellular localization of β-carotene 15,15′ oxygenase-1 (BCO1) and β-carotene 9′,10′ oxygenase-2 (BCO2) in rat liver and intestine

The intestine and liver are crucial organs for vitamin A uptake and storage. Liver accounts for 70% of total body retinoid stores. Vitamin A deficiency (VAD) is a major micronutrient deficiency around the world. The provitamin A carotenoid, β-carotene, is a significant source of vitamin A in the diet. β-Carotene 15,15′ oxygenase-1 (BCO1) and β-carotene 9′,10′ oxygenase-2 (BCO2) are the two known carotenoid cleavage enzymes in humans. BCO1 and BCO2 are highly expressed in liver and intestine. Hepatocytes and hepatic stellate cells are two main cell types involved in the hepatic metabolism of retinoids. Stellate-like cells in the intestine also show ability to store vitamin A. Liver is also known to accumulate carotenoids, however, their uptake, retention and metabolism in specific liver and intestinal cell types is still unknown. Hence, we studied the cellular and subcellular expression and localization of BCO1 and BCO2 proteins in rat liver and intestine. We demonstrate that both BCO1 and BCO2 proteins are localized in hepatocytes and mucosal epithelium. We also show that BCO1 is also highly expressed in hepatic stellate cells (HSC) and portal endothelial cells in liver. At the subcellular level in liver, BCO1 is found in cytosol, while BCO2 is found in mitochondria. In intestine, immunohistochemistry showed strong BCO1 immunoreactivity in the duodenum, particularly in Brunner’s glands. Both BCO1 and BCO2 showed diffuse presence along epithelia with strong immunoreactivity in endothelial cells and in certain epithelial cells which warrant further investigation as possible intestinal retinoid storage cells.

Proteomic profile of carbonylated proteins in rat liver: Discovering possible mechanisms for tetracycline‐induced steatosis

To investigate biochemical mechanisms for the tetracycline-induced steatosis in rats, targeted proteins of oxidative modification were profiled. The results showed that tetracycline induced lipid accumulation, oxidative stress, and cell viability decline in HepG2 cells only under the circumstances of palmitic acid overload. Tetracycline administration in rats led to significant decrement in blood lipids, while resulted in more than four times increment in intrahepatic triacylglycerol and typical microvesicular steatosis in the livers. The triacylglycerol levels were positively correlated with oxidative stress. Proteomic profiles of carbonylated proteins revealed 26 targeted proteins susceptible to oxidative modification and most of them located in mitochondria. Among them, the long-chain specific acyl-CoA dehydrogenase was one of the key enzymes regulating fatty acid β-oxidation. Oxidative modification of the enzyme in the tetracycline group depressed its enzymatic activity. In conclusion, the increased influx of lipid into the livers is the first hit of tetracycline-induced microvesicular steatosis. Oxidative stress is an essential part of the second hit, which may arise from the lipid overload and attack a series of functional proteins, aggravating the development of steatosis. The 26 targeted proteins revealed here provide a potential direct link between oxidative stress and tetracycline-induced steatosis.

Glucose and fructose have sugar-specific effects in both liver and skeletal muscle in vivo: a role for liver fructokinase.

We examined glucose and fructose effects on serine phosphorylation levels of a range of proteins in rat liver and muscle cells. For this, healthy adult rats were subjected to either oral glucose or fructose loads. A mini-array system was utilized to determine serine phosphorylation levels of liver and skeletal muscle proteins. A glucose oral load of 125 mg/100 g body weight (G 1/2) did not induce changes in phosphorylated serines of the proteins studied. Loading with 250 mg/100 g body weight of fructose (Fr), which induced similar glycemia levels as G 1/2, significantly increased serine phosphorylation of liver cyclin D3, PI3 kinase/p85, ERK-2, PTP2 and clusterin. The G 1/2 increased serine levels of the skeletal muscle proteins cyclin H, Cdk2, IRAK, total PKC, PTP1B, c-Raf 1, Ras and the β-subunit of the insulin receptor. The Fr induced a significant increase only in muscle serine phosphorylation of PI3 kinase/p85. The incubation of isolated rat hepatocytes with 10 mM glucose for 5 min significantly increased serine phosphorylation of 31 proteins. In contrast, incubation with 10 mM fructose produced less intense effects. Incubation with 10 mM glucose plus 75 µM fructose counteracted the effects of the incubation with glucose alone, except those on Raf-1 and Ras. Less marked effects were detected in cultured muscle cells incubated with 10 mM glucose or 10 mM glucose plus 75 µM fructose. Our results suggest that glucose and fructose act as specific functional modulators through a general mechanism that involves liver-generated signals, like micromolar fructosemia, which would inform peripheral tissues of the presence of either glucose- or fructose-derived metabolites.

Global molecular changes in rat livers treated with RXR agonists: a comparison using transcriptomics and proteomics

AbstractThe ability of the retinoid X receptors (RXRs) specific agonists (targretin [TRG] and UAB30) to alter rat liver gene and protein expression was determined using Affymetrix Exon arrays and high‐performance liquid chromatography – tandem mass spectrometry (LC‐MS/MS). TRG profoundly increases triglycerides levels while UAB30 does not. The expression patterns of transcripts or proteins from rat liver treated with TRG or UAB‐30 were different from controls and each other. There were six times more gene transcripts identified than proteins. Differentially expressed RNAs or proteins were mapped into known gene ontology (GO) categories and GeneGo Metacore (KEGG) pathway maps. The GO categories which were highly overrepresented with differentially expressed RNAs (P &lt; 10−16) were also overrepresented at the protein level. This high concordance of GO Terms was achieved despite the fact that typically ≤1/3 of the elements identified by gene expression were identified by proteomics. Within these GO categories, the magnitude of alterations induced by RXR agonists at the transcript and protein levels were correlated. When GO categories with moderate overrepresentation (10−5 &lt; P &lt; 10−9) were examined, there was greater discordance between the transcript and protein data. Examination of KEGG pathway maps with highly significant changes at both the protein and the RNA levels showed that the individual proteins/genes altered were often the same and changes were of similar magnitude; while KEGG pathways showed limited statistical significance and exhibited minimal overlap. Finally, metabolomics analysis of liver and serum identified altered expression of metabolites related to fatty acid oxidation and bile acid metabolism that were consistent with transcript/protein changes. We observed significant concordance between genomics and proteomics implying either can identify pathways modulated and can indirectly predict resulting physiologic effects.

Short‐term Type‐1 diabetes differentially modulates 14‐3‐3 proteins in rat brain and liver

The 14-3-3 proteins family consists of seven proteins that are highly conserved molecular chaperones with roles in the regulation of metabolism, signal transduction, cell cycle control, protein trafficking and apoptosis. Their role in several pathologies has been reported. In this study, we investigated the mRNA and protein expression of the 14-3-3s in rat brain and liver in the early stage of Type-1 diabetes (T1D). Diabetes was induced by a single intraperitoneal injection (70 mg/kg bw) of freshly prepared streptozotocin (STZ), and, after 3 weeks of treatment, brain and liver nuclei and cytosolic extracts were prepared. Quantitative real-time PCR and Western blotting analyses were performed to evaluate mRNA and protein expression for each of the seven 14-3-3s. In nondiabetic control rats, the expression profile of 14-3-3s revealed a tissue-specific distribution, and the expression level of each isoform was found higher in the brain than in the liver. In the diabetic brain, mRNA and protein levels of the 14-3-3β, ε, ζ, η and θ were lower; 14-3-3σ mRNA significantly increased while its protein level decreased. In the diabetic liver, the mRNA of 14-3-3γ, 14-3-3θ and 14-3-3σ significantly increased, but only the 14-3-3γ protein level increased. Overall, in diabetic animals, the changes in the expression levels of brain 14-3-3s were much more pronounced than in the liver. Our results indicate that during the early phase of STZ-induced T1D, the 14-3-3 proteins are affected in an isoform- and tissue-specific way.

Gender-dimorphic regulation of liver proteins in Streptozotocin-induced diabetic rats

To address the issue of gender importance in development of diabetes, in the present study, we performed two-dimensional gel electrophoresis (2-DE)-based proteomic study in Streptozotocin (STZ)-induced diabetic rats by investigating gender-dimorphic differential regulation patterns of liver proteins. Animal experiments revealed that females have greater susceptibility towards developing diabetes due to lower insulin secretion, greater severity of liver damage, more impaired regulation of sex hormones as well as lower glucose tolerance and higher blood glucose levels as compared to male diabetic rats when exposed to STZ. Proteomic analysis detected about 730 hepatic protein spots, ranging from 6 to 240 kDa mass between pH 3 ∼ 10, of which 45 identified proteins showed gender-dimorphic regulation. Most interesting is that our gender-specific proteome comparison showed that male and female rats displayed different regulations of hepatic proteins involved in lipid metabolism, methionine and citric acid cycles, as well as antioxidative and stress defense system. We for the first time identified chaperonin 10 and D-dopachrome tautomerase showing gender-dependent differential regulation between healthy control and diabetic rats, which have not been reported to date with respect to diabetes pathophysiology. In conclusion, current proteomic study revealed that more severely impaired hepatic protein regulation in female diabetic rats was influential on greater susceptibility of females to STZ-induced diabetes. We expect that the present proteomic data can provide valuable information for evidence-based gender-specific treatment of diabetes.

Analysis of Rat Liver Proteins by Peptide Immobilized pH Gradient Isoelectric Focusing Combined with Liquid Chromatography-Tandem Mass Spectrometry

Abstract Due to the complexity of the biological sample, it is important to develop an effective pre-separation method for the liquid chromatography-mass spectrometer (LC-MS) analysis of biological samples. In this experiment, enzymatic hydrolysate of rat liver protein was pre-separated by peptide immobilized pH gradient isoelectric focusing (IPG-IEF) method, and the pre-separated components were further separated by reversed physe liquid chromatography (RPLC) and then identified by LTQ-Orbitrap MS. A total of 2039 kinds of proteins were identified, including 18 kinds of acetylated proteins, 4 kinds of proteins which were never reported before. Next, bioinformatic analysis was carried out for these proteins. The results showed that peptide IPG-IEF coupled with LC-MS/MS is an effective technique for proteomics analysis and this method is suitable for large-scale protein identification.

Quantitative and Qualitative Proteome Characteristics Extracted from In-Depth Integrated Genomics and Proteomics Analysis

Quantitative and qualitative protein characteristics are regulated at genomic, transcriptomic, and posttranscriptional levels. Here, we integrated in-depth transcriptome and proteome analyses of liver tissues from two rat strains to unravel the interactions within and between these layers. We obtained peptide evidence for 26,463 rat liver proteins. We validated 1,195 gene predictions, 83 splice events, 126 proteins with nonsynonymous variants, and 20 isoforms with nonsynonymous RNA editing. Quantitative RNA sequencing and proteomics data correlate highly between strains but poorly among each other, indicating extensive nongenetic regulation. Our multilevel analysis identified a genomic variant in the promoter of the most differentially expressed gene Cyp17a1, a previously reported top hit in genome-wide association studies for human hypertension, as a potential contributor to the hypertension phenotype in SHR rats. These results demonstrate the power of and need for integrative analysis for understanding genetic control of molecular dynamics and phenotypic diversity in a system-wide manner.

Beneficial effects of Chrysin against Methotrexate-induced hepatotoxicity via attenuation of oxidative stress and apoptosis

Methotrexate (MTX), a folic acid antagonist, an effective chemotherapeutic agent is used in the treatment of a wide range of tumors and autoimmune diseases. Moreover, hepatotoxicity limits its clinical use. Several studies have already confirmed that the oxidative stress plays a major role in the pathogenesis of MTX-induced damage in the various organs especially in liver. The aim of this study was to determine the protective effect of Chrysin against MTX-induced hepatic oxidative stress and apoptosis in rats. In the present study, efficacy of Chrysin was investigated against hepatotoxicity caused by MTX in terms of biochemical investigations of antioxidant enzymes, apoptosis, and histopathological alteration in rat liver. In the MTX-treated group there was a significant increase in alanine transaminase, aspartate aminotransferase, lactate dehydrogenase activity and malondialdehyde content as well as decreased glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase activities and reduced glutathione content were also observed compared to the control group as a marker of oxidative stress. Histopathological alterations and apoptosis through the immunopositive staining of p53, cleaved caspases-3 and Bcl-2-associated X protein in rat liver were observed. Pretreatment of Chrysin at both doses prevents the hepatotoxicity by ameliorating oxidative stress, histopathological alterations, and apoptosis and thus our results suggest that Chrysin has a protective effect against hepatotoxicity induced by MTX and it may, therefore, improve the therapeutic index of MTX if co-administration is done.