Hepatic Induction Research Articles

8-Hydroxy-2'-Deoxyguanosin in Peripheral Leukocyte Associated With HBsAg in Patients with Chronic Hepatitis B

Background: Chronic hepatitis B (CHB), with accumulation of Hepatitis B surface Antigen (HBsAg) in hepatocytes, linked to the immune-mediated hepatic inflammation and induction of oxidative stress. 8-Hydroxyl-2'-deoxyguanosine (8-OHdG) is a useful biomarker for measuring the adverse effects of exogenous infectious agents in oxidative damage to DNA. Objectives: The current study aimed at investigating the possible oxidative adverse effects of HBsAg and systemic DNA damage in patients with CHB, and supporting the host-viral interaction in immune-mediated inflammatory. Methods: Thirty patients with CHB who had undergone liver biopsies for therapeutic purposes and 30 matched controls from a healthy population were randomly selected in the present study for assessment of 8-OHdG levels in peripheral blood leukocytes DNA by 32P-postlabeling analysis. Expression of HBsAg in hepatocytes was evaluated immunohistochemically in liver biopsies of patients with CHB. The effect of 8-OHdG and 95% confidence interval (CI), adjusted by relevant confounders, were assessed on hepatitis B virus (HBV) infection. Results: Experimental investigation showed increased levels of DNA adduct 8-OHdG compared with healthy individuals (mean ± standard deviation, 1456 ± 1275 vs. 402 ± 271; P < 0.001). The logistic regression with continuous and dichotomous models revealed the strong impact of 8-OHdG on CHB infection (OR = 1.20; 95%CI: 1.01 - 1.44, P = 0.043) and (OR = 7.18; 95%CI: 1.32 - 39.02, P = 0.022). HBV DNA and hepatic expression of HBsAg had a borderline association with DNA adduct 8-OHdG (r = 0.35, P = 0.054 and r = 0.36, P = 0.05). Conclusions: The current study showed that the adduct of 8-OHdG in peripheral blood cells DNA increased in patients with CHB compared with healthy carriers and the pathophysiologic role of HBsAg in oxidative stress in patients with CHB. Nonetheless, the lack of efficient DNA repair enzymes activity as well as a proper diet with antioxidant agents in CHB need to be clarified in future studies.

Paracrine signals regulate human liver organoid maturation from induced pluripotent stem cells.

A self-organizing organoid model provides a new approach to study the mechanism of human liver organogenesis. Previous animal models documented that simultaneous paracrine signaling and cell-to-cell surface contact regulate hepatocyte differentiation. To dissect the relative contributions of the paracrine effects, we first established a liver organoid using human induced pluripotent stem cells (iPSCs), mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) as previously reported. Time-lapse imaging showed that hepatic-specified endoderm iPSCs (HE-iPSCs) self-assembled into three-dimensional organoids, resulting in hepatic gene induction. Progressive differentiation was demonstrated by hepatic protein production after in vivo organoid transplantation. To assess the paracrine contributions, we employed a Transwell system in which HE-iPSCs were separately co-cultured with MSCs and/or HUVECs. Although the three-dimensional structure did not form, their soluble factors induced a hepatocyte-like phenotype in HE-iPSCs, resulting in the expression of bile salt export pump. In conclusion, the mesoderm-derived paracrine signals promote hepatocyte maturation in liver organoids, but organoid self-organization requires cell-to-cell surface contact. Our in vitro model demonstrates a novel approach to identify developmental paracrine signals regulating the differentiation of human hepatocytes.

MiR-200c Accelerates Hepatic Stellate Cell-Induced Liver Fibrosis via Targeting the FOG2/PI3K Pathway.

Background Although expression of miR-200s is aberrant in liver fibrosis, its role in liver fibrogenesis still remains unknown. Here, we investigated the role of miR-200c in the activation of human hepatic stellate cells (HSCs) and induction of liver fibrosis. Methods We engineered human HSCs (LX2 cell line) to stably express miR-200c (LX2-200c) or empty vector control (LX2-nc). Results miR-200c expression upregulated α-smooth muscle actin (SMA) and vimentin, enhanced HSCs growth and migration, increased expression of collagen type I (a main component of ECM) gene and secretion of epidermal growth factor (EGF), and upregulated the phosphorylation of Akt, a downstream effector of the PI3K pathway. As a target of miR-200s and inhibitor of PI3K pathway, FOG2 protein expression was significantly suppressed in LX2-200c cells. Moreover, LY294002, a highly selective inhibitor of PI3K, blocked phosphorylation of Akt and the effects of miR-200c. Conclusions These data suggest that miR-200c activates HSCs in liver fibrosis possibly by downregulating FOG2 protein expression and upregulating PI3K/Akt signaling. Autocrine activation of EGF signaling may also be a mechanism of miR-200c-mediated HSCs activation. So miR-200c can be a potential marker for HSCs activation and liver fibrosis progression, as well as a potential target to attenuate liver fibrosis.

Extreme liver resections with preservation of segment 4 only.

AIMTo evaluate safety and outcomes of a new technique for extreme hepatic resections with preservation of segment 4 only.METHODSThe new method of extreme liver resection consists of a two-stage hepatectomy. The first stage involves a right hepatectomy with middle hepatic vein preservation and induction of left lobe congestion; the second stage involves a left lobectomy. Thus, the remnant liver is represented by the segment 4 only (with or without segment 1, ± S1). Five patients underwent the new two-stage hepatectomy (congestion group). Data from volumetric assessment made before the second stage was compared with that of 10 matched patients (comparison group) that underwent a single-stage right hepatectomy with middle hepatic vein preservation.RESULTSThe two stages of the procedure were successfully carried out on all 5 patients. For the congestion group, the overall volume of the left hemiliver had increased 103% (mean increase from 438 mL to 890 mL) at 4 wk after the first stage of the procedure. Hypertrophy of the future liver remnant (i.e., segment 4 ± S1) was higher than that of segments 2 and 3 (144% vs 54%, respectively, P < 0.05). The median remnant liver volume-to-body weight ratio was 0.3 (range, 0.28-0.40) before the first stage and 0.8 (range, 0.45-0.97) before the second stage. For the comparison group, the rate of hypertrophy of the left liver after right hepatectomy with middle hepatic vein preservation was 116% ± 34%. Hypertrophy rates of segments 2 and 3 (123% ± 47%) and of segment 4 (108% ± 60%, P > 0.05) were proportional. The mean preoperative volume of segments 2 and 3 was 256 ± 64 cc and increased to 572 ± 257 cc after right hepatectomy. Mean preoperative volume of segment 4 increased from 211 ± 75 cc to 439 ± 180 cc after surgery.CONCLUSIONThe proposed method for extreme hepatectomy with preservation of segment 4 only represents a technique that could allow complete resection of multiple bilateral liver metastases.

Lymphocytes contribute to biliary injury and fibrosis in experimental xenobiotic-induced cholestasis

The etiology of chronic bile duct injury and fibrosis in patients with autoimmune cholestatic liver diseases is complex, and likely involves immune cells such as lymphocytes. However, most models of biliary fibrosis are not autoimmune in nature. Biliary fibrosis can be induced experimentally by prolonged exposure of mice to the bile duct toxicant alpha-naphthylisothiocyanate (ANIT). We determined whether lymphocytes contributed to ANIT-mediated biliary hyperplasia and fibrosis in mice. Hepatic accumulation of T-lymphocytes and increased serum levels of anti-nuclear-autoantibodies were evident in wild-type mice exposed to ANIT (0.05% ANIT in chow). This occurred alongside bile duct hyperplasia and biliary fibrosis. To assess the role of lymphocytes in ANIT-induced biliary fibrosis, we utilized RAG1-/- mice, which lack T- and B-lymphocytes. ANIT-induced bile duct injury, indicated by increased serum alkaline phosphatase activity, was reduced in ANIT-exposed RAG1-/- mice compared to ANIT-exposed wild-type mice. Despite this reduction in biliary injury, ANIT-induced bile duct hyperplasia was similar in wild-type and RAG1-/- mice. However, hepatic induction of profibrogenic genes including COL1A1, ITGβ6 and TGFβ2 was markedly attenuated in ANIT-exposed RAG1-/- mice compared to ANIT-exposed wild-type mice. Peribiliary collagen deposition was also reduced in ANIT-exposed RAG1-/- mice. The results indicate that lymphocytes exacerbate bile duct injury and fibrosis in ANIT-exposed mice without impacting bile duct hyperplasia.

Impaired Hepatic Adaptation to Chronic Cholestasis induced by Primary Sclerosing Cholangitis.

Pathogenesis of primary sclerosing cholangitis (PSC) may involve impaired bile acid (BA) homeostasis. We analyzed expressions of factors mediating enterohepatic circulation of BA using ileal and colonic (ascending and sigmoid) biopsies obtained from patients with PSC with and without ulcerative colitis (UC) and explanted PSC livers. Two-fold increase of BA-activated farnesoid X receptor (FXR) protein levels were seen in ascending and sigmoid colon of PSC patients with correspondingly decreased apical sodium-dependent BA transporter (ASBT) gene expression. This was associated with increased OSTβ protein levels in each part of analyzed gut. An intestinal fibroblast growth factor (FGF19) protein expression was significantly enhanced in ascending colon. Despite increased hepatic nuclear receptors (FXR, CAR, SHP), and FGF19, neither CYP7A1 suppression nor CYP3A4 induction were observed. The lack of negative regulation of BA synthesis may be accountable for lower levels of cholesterol observed in PSC in comparison to primary biliary cholangitis (PBC). In conclusion, chronic cholestasis in PSC induces adaptive changes in expression of BA transporters and FXR in the intestine. However hepatic impairment of expected in chronic cholestasis downregulation of CYP7A1 and upregulation of CYP3A4 may promote BA-induced liver injury in PSC.

Nutrigenomic effects of glucosinolates on liver, muscle and distal kidney in parasite-free and salmon louse infected Atlantic salmon.

BackgroundReduction of Lepeophtheirus salmonis infection in Atlantic salmon achieved by glucosinolates (GLs) from Brassica plants was recently reported. However, wider application of functional feeds based on GLs requires better knowledge of their positive and adverse effects.MethodsLiver, distal kidney and muscle transcriptomes of salmon exposed to the extreme dose of GLs were profiled by microarray, while qPCR analysis followed up selected hepatic and renal responses under the extreme and moderate GLs dose during the L. salmonis challenge. Transcriptional analysis were complemented with measurements of organ indices, liver steatosis and plasma profiling, including indicators of cytolysis and bilirubin. Finally, the third trial was performed to quantify the effect of lower GLs doses on growth.ResultsThe extreme GLs dose caused a decrease in hepatic fat deposition and growth, in line with microarray findings, which suggested tissue remodeling and reduction of cellular proliferation in the skeletal muscle and liver. Lower GLs inclusion levels in a follow-up trial did not show negative effects on growth. Microarray analysis of the distal kidney pointed to activation of anti-fibrotic responses under the overexposure. However, analyses of ALT, CK and AST enzymes in plasma provided no evidence of increased cytolysis and organ damage. Prevalent activation of phase-2 detoxification genes that occurred in all three tissues could be considered part of beneficial effects caused by the extreme dose of GLs. In addition, transcriptomic evidence suggested GLs-mediated iron and heme withdrawal response, including increased heme degradation in muscle (upregulation of heme oxygenase-1), decrease of its synthesis in liver (downregulation of porphobilinogen deaminase) and increased iron sequestration from blood (hepatic induction of hepcidin-1 and renal induction of intracellular storage protein ferritin). This response could be advantageous for salmon upon encountering lice, which depend on the host for the provision of iron carrying heme. Most of the hepatic genes studied by qPCR showed similar expression levels in fish exposed to GLs, lice and their combination, while renal induction of leptin suggested heightened stress by the combination of extreme dose of GLs and lice. High expression of interferon γ (cytokine considered organ-protective in mammalian kidney) was detected at the moderate GLs level. This fish also showed highest plasma bilirubin levels (degradation product of heme), and had lowest number of attached lice, further supporting hypothesis that making heme unavailable to lice could be part of an effective anti-parasitic strategy.ConclusionsModulation of detoxification and iron metabolism in Atlantic salmon tissues could be beneficial prior and during lice infestations. Investigation of anti-lice functional feeds based on low and moderate GLs inclusion levels thus deserves further attention.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1921-7) contains supplementary material, which is available to authorized users.

92 - Decreased Hepatic Polyunsaturated Fatty Acids and Inflammatory Response in a Rat Model of Endoplasmic Reticulum Stress

In this study, we sought to evaluate the effect of endoplasmic reticulum (ER) stress on hepatic polyunsaturated fatty acids (PUFAs) and inflammatory response through cyclooxygenase (COX)-mediated pathway. Male Wistar rats which were allowed free access to standard rat chow were randomly divided into control, tunicamycin (TM) treated and TM + tauroursodeoxycholic acid (TUDCA) treated groups. Hepatic ER stress was induced by intraperitoneal injection of tunicamycin and the ER stress inhibitor TUDCA was injected 30 minutes before hepatic induction of ER stress. The presence of ER stress was confirmed by increased intracellular levels of C/EBP-homologous protein (CHOP) and 78-kDa glucose-regulated protein (GRP78). Necroinflammation was evaluated in liver sections stained with hematoxylin-eosin using the Ishak-modified hepatic activity index. Levels of arachidonic acid (AA, C20:4n-6), dihomo-gamma-linolenic acid (DGLA, C20:3n-6), eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3) in liver tissue were determined by an optimized multiple reaction monitoring method using ultra fast-liquid chromatography coupled with tandem mass spectrometry. Phospholipase A2 (PLA2), COX and prostaglandin E2 (PGE2) were measured in tissue samples to evaluate changes in the inflammatory pathways. Tunicamycin treatment significantly decreased all measured PUFAs and increased AA/EPA ratio in liver tissue compared to controls. Tissue activity of PLA2, COX and PGE2 levels were significantly increased in liver tissue of TM treated rats compared to controls. Tauroursodeoxycholic acid lead to a partial restoration of liver PUFA levels and significantly decreased PLA2, COX and PGE2 levels compared to TM treated rats. The results of this study reveal the presence of a proinflammatory state in hepatic ER stress as shown by significantly increased AA/EPA ratio. To our best knowledge, this is the first study reporting altered PUFA levels in ER stress and supports the use of omega-3 fatty acids as adjuvant treatment in liver diseases demonstrating ER stress. Acknowledgement This study was supported by a grant from TUBITAK; # 214S223.

Mechanisms for Hepatobiliary Toxicity in Rats Treated with an Antagonist of Melanin Concentrating Hormone Receptor 1 (MCHR1).

The objective of this work was to investigate the mechanisms of hepatobiliary toxicity caused by thienopyrimidone MCHR1 antagonists using BMS-773174 as a tool molecule. Co-administration of the pan CYP inhibitor 1-aminobenzotriazole with BMS-773174 prevented hepatobiliary damage, and direct delivery of the diol metabolite BMS-769750 caused hepatobiliary toxicity, identifying the diol and possibly its downstream hydroxyacid (BMS-800754) metabolite as the toxic species. Rat liver gene expression revealed treatment-related changes in hepatic transporters and induction of oval cell-specific genes including deleted malignant tumor 1 (Dmbt1). The metabolites did not alter hepatic transporter activities, suggesting that transporter-mediated cholestasis was not involved. Because injury to biliary epithelium can result in adaptive hyperplasia, rat biliary epithelial cells (BECs) were isolated and exposed to the oxidative metabolites. BMS-769750 was cytotoxic to BECs, but not rat hepatocytes, suggesting a role of the diol in biliary epithelial injury. BMS-800754 was cytotoxic to rat hepatocytes therefore its contribution to hepatocyte injury in rats is a possibility. Induction of Dmbt1 in rat BECs was investigated because of its role in hepatic progenitor cell differentiation/proliferation during injury. Dmbt1 mRNA was induced by BMS-769750, but not BMS-800754 in BECs; this induction and cellular injury was confirmed with diol metabolites formed by other compounds with the same hepatobiliary liability. In conclusion, hepatobiliary injury by thienopyrimidinone MCHR1 antagonists was driven through a CYP-mediated bioactivation pathway. Induction of Dmbt1 mRNA coupled with cellular injury suggests that injury of biliary epithelium may be the first step toward an adaptive proliferative response causing BDH by these compounds.

Glycine prevents metabolic steatohepatitis in diabetic KK-Ay mice through modulation of hepatic innate immunity.

Strategies for prevention and treatment of nonalcoholic steatohepatitis remain to be established. We evaluated the effect of glycine on metabolic steatohepatitis in genetically obese, diabetic KK-Ay mice. Male KK-Ay mice were fed a diet containing 5% glycine for 4 wk, and liver pathology was evaluated. Hepatic mRNA levels for lipid-regulating molecules, cytokines/chemokines, and macrophage M1/M2 markers were determined by real-time RT-PCR. Hepatic expression of natural killer (NK) T cells was analyzed by flow cytometry. Body weight gain was significantly blunted and development of hepatic steatosis and inflammatory infiltration were remarkably prevented in mice fed the glycine-containing diet compared with controls. Indeed, hepatic induction levels of molecules related to lipogenesis were largely blunted in the glycine diet-fed mice. Elevations of hepatic mRNA levels for TNFα and chemokine (C-C motif) ligand 2 were also remarkably blunted in the glycine diet-fed mice. Furthermore, suppression of hepatic NK T cells was reversed in glycine diet-fed KK-Ay mice, and basal hepatic expression levels of NK T cell-derived cytokines, such as IL-4 and IL-13, were increased. Moreover, hepatic mRNA levels of arginase-1, a marker of macrophage M2 transformation, were significantly increased in glycine diet-fed mice. In addition, dietary glycine improved glucose tolerance and hyperinsulinemia in KK-Ay mice. These observations clearly indicate that glycine prevents maturity-onset obesity and metabolic steatohepatitis in genetically diabetic KK-Ay mice. The underlying mechanisms most likely include normalization of hepatic innate immune responses involving NK T cells and M2 transformation of Kupffer cells. It is proposed that glycine is a promising immunonutrient for prevention and treatment of metabolic syndrome-related nonalcoholic steatohepatitis.

Efficient generation of hepatic cells from mesenchymal stromal cells by an innovative bio-microfluidic cell culture device.

BackgroundMesenchymal stromal cells (MSCs) are multipotent and have great potential in cell therapy. Previously we reported the differentiation potential of human MSCs into hepatocytes in vitro and that these cells can rescue fulminant hepatic failure. However, the conventional static culture method neither maintains growth factors at an optimal level constantly nor removes cellular waste efficiently. In addition, not only is the duration of differentiating hepatocyte lineage cells from MSCs required to improve, but also the need for a large number of hepatocytes for cell therapy has not to date been addressed fully. The purpose of this study is to design and develop an innovative microfluidic device to overcome these shortcomings.MethodsWe designed and fabricated a microfluidic device and a culture system for hepatic differentiation of MSCs using our protocol reported previously. The microfluidic device contains a large culture chamber with a stable uniform flow to allow homogeneous distribution and expansion as well as efficient induction of hepatic differentiation for MSCs.ResultsThe device enables real-time observation under light microscopy and exhibits a better differentiation efficiency for MSCs compared with conventional static culture. MSCs grown in the microfluidic device showed a higher level of hepatocyte marker gene expression under hepatic induction. Functional analysis of hepatic differentiation demonstrated significantly higher urea production in the microfluidic device after 21 days of hepatic differentiation.ConclusionsThe microfluidic device allows the generation of a large number of MSCs and induces hepatic differentiation of MSCs efficiently. The device can be adapted for scale-up production of hepatic cells from MSCs for cellular therapy.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-016-0371-7) contains supplementary material, which is available to authorized users.

Autophagy confers resistance to lipopolysaccharide-induced mouse hepatocyte injury.

During sepsis, bacterial products, particularly LPS, trigger injury in organs such as the liver. This common condition remains largely untreatable, in part due to a lack of understanding of how high concentrations of LPS cause cellular injury. In the liver, the lysosomal degradative pathway of autophagy performs essential hepatoprotective functions and is induced by LPS. We, therefore, examined whether hepatocyte autophagy protects against liver injury from septic levels of LPS. Mice with an inducible hepatocyte-specific knockout of the critical autophagy gene Atg7 were examined for their sensitivity to high-dose LPS. Increased liver injury occurred in knockout mice, as determined by significantly increased serum alanine aminotransferase levels, histological evidence of liver injury, terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick end-labeling, and effector caspase-3 and -7 activation. Hepatic inflammation and proinflammatory cytokine induction were unaffected by the decrease in hepatocyte autophagy. Although knockout mice had normal NF-κB signaling, hepatic levels of Akt1 and Akt2 phosphorylation in response to LPS were decreased. Cultured hepatocytes from knockout mice displayed a generalized defect in Akt signaling in response to multiple stimuli, including LPS, TNF, and IL-1β. Akt activation mediates hepatocyte resistance to TNF cytotoxicity, and anti-TNF antibodies significantly decreased LPS-induced liver injury in knockout mice, indicating that the loss of autophagy sensitized to TNF-dependent liver damage. Hepatocyte autophagy, therefore, protects against LPS-induced liver injury. Conditions such as aging and steatosis that impair hepatic autophagy may predispose to poor outcomes from sepsis through this mechanism.

The Orphan Nuclear Receptor ERRγ Regulates Hepatic CB1 Receptor-Mediated Fibroblast Growth Factor 21 Gene Expression.

BackgroundFibroblast growth factor 21 (FGF21), a stress inducible hepatokine, is synthesized in the liver and plays important roles in glucose and lipid metabolism. However, the mechanism of hepatic cannabinoid type 1 (CB1) receptor-mediated induction of FGF21 gene expression is largely unknown.ResultsActivation of the hepatic CB1 receptor by arachidonyl-2’-chloroethylamide (ACEA), a CB1 receptor selective agonist, significantly increased FGF21 gene expression. Overexpression of estrogen-related receptor (ERR) γ increased FGF21 gene expression and secretion both in hepatocytes and mice, whereas knockdown of ERRγ decreased ACEA-mediated FGF21 gene expression and secretion. Moreover, ERRγ, but not ERRα and ERRβ, induced FGF21 gene promoter activity. In addition, deletion and mutation analysis of the FGF21 promoter identified a putative ERRγ-binding motif (AGGTGC, a near-consensus response element). A chromatin immunoprecipitation assay revealed direct binding of ERRγ to the FGF21 gene promoter. Finally, GSK5182, an ERRγ inverse agonist, significantly inhibited hepatic CB1 receptor-mediated FGF21 gene expression and secretion.ConclusionBased on our data, we conclude that ERRγ plays a key role in hepatic CB1 receptor-mediated induction of FGF21 gene expression and secretion.

Efficacy of levetiracetam in primary hemifacial spasm

Hemifacial spasm (HFS) is a peripherally-induced movement disorder characterized by the involuntary, unilateral, intermittent, irregular, tonic or clonic contractions of muscles innervated by the ipsilateral facial nerve. Kindling-like hyperactivity of the facial nucleus induced by constant stimulation of compressing artery is considered as the predominant mechanism underlying the pathogenesis of HFS. As a treatment for HFS, microsurgical decompression and botulinum toxin injection have been shown to be highly successful. Anticonvulsant drugs relieve HFS in some patients; however, the use of such drugs is limited owing to their side effects, predominantly in elderly patients. We experienced two elderly HFS patients who exhibited a marked response to levetiracetam (LEV) without side effects. Although the exact underlying pharmacological mechanism remains unknown, we assume anti-kindling effect as one of the important pharmacological mechanism underlying the effect of LEV against HFS. Moreover, LEV is considered to be suitable for use in elderly patients because of its good tolerability. In addition, the lack of hepatic induction or inhibition makes it an easy and safe drug when used in addition to other anticonvulsants. Although the long-term benefit remains unknown, LEV may represent an alternative treatment for elderly HFS patients who are unable to undergo or decline surgical intervention and/or botulinum toxin injections or are intolerant to other anticonvulsants.

Abstract 4068: Role of cytochrome P450 (CYP)1A2 in the molecular regulation of CYP1A1 by the carcinogen, 3-methylcholanthrene (MC) in mouse heptoma cells (hepa-1)

Abstract Cytochrome P4501A (CYP1A) enzymes play important roles in the activation of PAHs such as 3-methylcholanthrene (MC) to carcinogenic DNA-binding metabolites. We reported earlier that MC causes persistent induction of hepatic and pulmonary CYP1A1 in mice for several weeks after MC withdrawal, and that the phenomenon of sustained hepatic CYP1A1 induction is lost in Cyp1a2-null mice. In this study, we tested the hypothesis that MC elicits induction of persistent CYP1A1 induction in hepa-1 cells, and that CYP1A2 contributes mechanistically to this phenomenon. Hepa-1 cells were treated with the MC (2.5 μM), or dimethylsulfoxide (DMSO) as control, and at selected time points, CYP1A1 promoter activity, CYP1A1 enzyme activities, contents, and CYP1A1 mRNA levels were studied. A 24 h treatment induced the CYP1A1 promoter activity, CYP1A1 mRNA, and ethoxyresorufin O-deethylase (EROD) activity by 2-, 1000-, and 15-fold, respectively. The induction was sustained for 4-5 days. MC persistently induced CYP1A1 apoprotein level as well. Electrophoretic mobility shift assay indicated that MC induced a nuclear protein that bound to aryl hydrocarbon response elements in the CYP1A1 promoter region. Transfection of CYP1A2 siRNA resulted in knockdown of CYP1A2 mRNA by 70%, but a statistically significant increase of basal CYP1A1 mRNA by 35-40%. The induction of CYP1A1 promoter activity, CYP1A1 mRNA, CYP1A1 protein, and EROD activity by MC were not affected by CYP1A2 siRNA at the 24 h time point, but was significantly attenuated by CYP1A2 siRNA on day 5. These results suggest that CYP1A2, possibly via a metabolite, contributes to the sustained induction of CYP1A1 by MC in hepa-I cells. Further investigations into the mechanisms of persistent induction of CYP1A1 by MC could lead to novel preventative/therapeutic strategies against PAH-mediated carcinogenesis in humans. Citation Format: Sudha Kondraganti, Chun Chu, Bhagavatula Moorthy. Role of cytochrome P450 (CYP)1A2 in the molecular regulation of CYP1A1 by the carcinogen, 3-methylcholanthrene (MC) in mouse heptoma cells (hepa-1). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4068.

Hepatoprotective Effect of Captopril on Liver Toxicity Induced by High and Low Dose of Paracetamol in Rats:Histological Study

Many patients may administered medications like captopril (ACE inhibitor) for treatment of chronic diseases and may also take Paracetamol as an Over The Counter (OTC) drug which may interact with captopril. Therefore, the aim of this study is to evaluate of the hepatoprotective effect of captopril on liver toxicity induced by low and high dose of paracetamol in rats. This study was conducted in two phases: first study for low dose of paracetamol (300 mg/kg); animals were divided into 4 groups of 6 rats each (n = 6); all groups were treated orally either 0.9 % Normal Saline (NS), captopril 20 mg/kg, paracetamol 300 mg/kg or captopril 20 mg/kg plus paracetamol 300 mg/kg for 10 consecutive days. Second study for single high dose of paracetamol (3000 mg/kg); animals were divided into 4 groups of 6 rats each (n = 6); all groups were pretreated orally either 0.9 % Normal Saline (NS) or captopril 20 mg/kg for 7 consecutive days followed by single oral administration of Paracetamol 3000 mg/kg or normal saline. The administration of Paracetamol or normal saline was performed 24 hours after the last administration of captopril. After 48 hours of hepatic injury induction, the animals were then sacrificed and the liver was removed for histopathological studies. Low dose (300 mg/kg) for 10 days and high single dose (3000 mg/kg) of paracetamol produced hepatotoxic effects. While captopril 20 mg/kg showed marked protection against changes induced by low and high dose of paracetamol on the liver.

Hepatoprotective action of various partitions of methanol extract of Bauhinia purpurea leaves against paracetamol-induced liver toxicity: involvement of the antioxidant mechanisms.

BackgroundMethanol extract of Bauhinia purpurea L. (family Fabaceae) (MEBP) possesses high antioxidant and anti-inflammatory activities and recently reported to exert hepatoprotection against paracetamol (PCM)-induced liver injury in rats. In an attempt to identify the hepatoprotective bioactive compounds in MEBP, the extract was prepared in different partitions and subjected to the PCM-induced liver injury model in rats.MethodsDried MEBP was partitioned successively to obtain petroleum ether (PEBP), ethylacetate (EABP) and aqueous (AQBP) partitions, respectively. All partitions were subjected to in vitro antioxidant (i.e. total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH)- and superoxide-radicals scavenging assay, and oxygen radical absorbance capacity (ORAC) assay) and anti-inflammatory (i.e. lipooxygenase (LOX) and xanthine oxidase (XO) assay) analysis. The partitions, prepared in the dose range of 50, 250 and 500 mg/kg, together with a vehicle (10 % DMSO) and standard drug (200 mg/kg silymarin) were administered orally for 7 consecutive days prior to subjection to the 3 mg/kg PCM-induced liver injury model in rats. Following the hepatic injury induction, blood samples and liver were collected for the respective biochemical parameter and histopathological studies. Body weight changes and liver weight were also recorded. The partitions were also subjected to the phytochemical screening and HPLC analysis.ResultsOf all partitions, EABP possessed high TPC value and demonstrated remarkable antioxidant activity when assessed using the DPPH- and superoxide-radical scavenging assay, as well as ORAC assay, which was followed by AQBP and PEBP. All partitions also showed low anti-inflammatory activity via the LOX and XO pathways. In the hepatoprotective study, the effectiveness of the partitions is in the order of EABP>AQBP>PEBP, which is supported by the microscopic analysis and histopathological scoring. In the biochemical analysis, EABP also exerted the most effective effect by reducing the serum level of alanine transaminase (ALT) and aspartate transaminase (AST) at all doses tested in comparison to the other partitions. Phytochemical screening and HPLC analysis suggested the presence of: flavonoids, condensed tannins and triterpenes in EABP; flavonoids, condensed tannins and saponins in PEBP and; only saponins in AQBP.ConclusionEABP demonstrates the most effective hepatoprotection against PCM-induced liver injury in rats. This observation could be attributed to its remarkable antioxidant activity and the presence of flavonoids that might probably act synergistically with other biocompounds to cause the hepatoprotection.

Current status and future perspectives of hepatic induction and maturation of iPS cells for drug developments

Current status and future perspectives of hepatic induction and maturation of iPS cells for drug developments

Effects of duration of phenytoin administration on mRNA expression of cytochrome P450 and P-glycoprotein in the liver and small intestine of rats

Phenytoin (5,5-diphenylhydantoin; DPH) induces expression of cytochromes P450 (CYPs). Interactions between DPH and tacrolimus suggested that the persistence of CYP induction after discontinuation of DPH is dependent on the history of administration and dosing period of DPH. However, the relationship between the duration of DPH administration and expression of CYPs in the liver and small intestine of rats is not known. Alterations in levels of P-glycoprotein (P-gp; MDR1; ABCB1) as well as CYPs cause drug interactions in the small intestine. We examined the effects of the duration of DPH administration on expression of CYPs and P-gp in the liver and small intestine of rats. Rats were treated with DPH (100 mg/kg, peroral (p.o.) twice a day (b.d.)) for 2, 4, 8, and 16 d. mRNA levels of CYPs and P-gp were examined using the total RNA extracted from the liver and duodenum 2 h and 24 h after the final administration of DPH. CYP3A activities were determined using microsomes. DPH administration for 2 d and 4 d markedly increased mRNA levels of CYPs such as CYP3A1, CYP3A2, CYP2B1, and CYP2B2 in the liver. A relatively long duration of DPH administration (8 d and 16 d) resulted in abolition of the induction of hepatic CYP but increased CYP3A activities were maintained. These results suggest that the duration of DPH administration could be an important determinant of hepatic CYP induction.

Assessment of the Mitigative Capacity of Dietary Zinc on PCB126 Hepatotoxicity and the Contribution of Zinc to Toxicity.

Hepatic levels of the essential micronutrient, zinc, are diminished by several hepatotoxicants, and the dietary supplementation of zinc has proven protective in those cases. 3,3',4,4',5-Pentachlorobiphenyl (PCB126), a liver toxicant, alters hepatic nutrient homeostasis and lowers hepatic zinc levels. The current study was designed to determine the mitigative potential of dietary zinc in the toxicity associated with PCB126 and the role of zinc in that toxicity. Male Sprague-Dawley rats were divided into three dietary groups and fed diets deficient in zinc (7 ppm Zn), adequate in zinc (30 ppm Zn), and supplemented in zinc (300 ppm). The animals were maintained for 3 weeks on these diets, then given a single IP injection of vehicle or 1 or 5 μmol/kg PCB126. After 2 weeks, the animals were euthanized. Dietary zinc increased the level of ROS, the activity of CuZnSOD, and the expression of metallothionein but decreased the levels of hepatic manganese. PCB126 exposed rats exhibited classic signs of exposure, including hepatomegaly, increased hepatic lipids, increased ROS and CYP induction. Liver histology suggests some mild ameliorative properties of both zinc deficiency and zinc supplementation. Other metrics of toxicity (relative liver and thymus weights, hepatic lipids, and hepatic ROS) did not support this trend. Interestingly, the zinc supplemented high dose PCB126 group had mildly improved histology and less efficacious induction of investigated genes than did the low dose PCB126 group. Overall, decreases in zinc caused by PCB126 likely contribute little to the ongoing toxicity, and the mitigative/preventive capacity of zinc against PCB126 exposure seems limited.