Untargeted liquid chromatography-mass spectrometry metabolomics to assess drug-induced cholestatic features in HepaRG® cells

Cholestasis is a liver disease associated with retention of bile in the liver, which leads to local hepatic inflammation and severe liver damage. In order to investigate the mode of action of drug-induced cholestasis, in vitro models have shown to be able to recapitulate important elements of this disease. In this study, we applied untargeted metabolomics to investigate the metabolic perturbances in HepaRG® cells exposed for 24 h and 72 h to bosentan, a cholestatic reference toxicant. Intracellular profiles were extracted and analysed with liquid chromatography and accurate-mass spectrometry. Metabolites of interest were selected using partial least-squares discriminant analysis and random forest classifier models. The observed metabolic patterns associated with cholestasis in vitro were complex. Acute (24 h) exposure revealed metabolites related to apoptosis, such as ceramide and triglyceride accumulation, in combination with phosphatidylethanolamine, choline and carnitine depletion. Metabolomic alterations during exposure to lower dosages and a prolonged exposure (72 h) included carnitine upregulation and changes in the polyamine metabolism. These metabolites were linked to changes in phospholipid metabolism, mitochondrial pathways and energy homeostasis. The metabolic changes confirmed the mitotoxic effects of bosentan and revealed the potential involvement of phospholipid metabolism as part of the mode of action of drug-induced cholestasis.

Chemoprevention of Diethylnitrosamine-Initiated and Phenobarbital-Promoted Hepatocarcinogenesis in Rats by Sulfated Polysaccharides and Aqueous Extract of Ulva lactuca

Hepatocellular carcinoma (HCC) is one of the common cancers and lethal diseases worldwide. Both oxidative stress and chronic inflammation contribute to the pathogenesis of HCC. Because of limited treatment options and a grave prognosis of HCC, preventive management has been emphasized. The marine macroalgae Ulva lactuca (Ulvaceae) is consumed by humans and livestock because of its nutritional value. Recent studies showed that various extracts of U. lactuca possess antiviral, antiplasmodial, antinephrotoxic, antioxidant, and anti-inflammatory properties. However, very limited information is available on anticancer potential of U. lactuca with no reports on liver cancer chemopreventive efficacy of this marine algae. Accordingly, the present study was initiated to evaluate the possible antihepatocarcinogenic effects and antioxidant mechanisms of action of various U. lactuca extracts against a clinically relevant rodent model of HCC. Initiation of hepatocarcinogenesis was performed in Sprague-Dawley rats by a single injection of dietary carcinogen diethylnitrosamine (DENA, 200 mg/kg, intraperitoneally), followed by promotion with phenobarbital (0.05%) in drinking water. The rats were fed with daily oral dose (50 mg/kg) of polysaccharide sulfate or aqueous extract of U. lactuca for 2, 12, and 24 weeks. At these timepoints, blood samples were taken to measure hepatic injury markers, including alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transferase, and bilirubin. The liver tissue was harvested for measurement of hepatic oxidative indices, including lipid peroxidation, reduced glutathione, nitric oxide, catalase, superoxide dismutase, glutathione reductase, and glutathione S-transferase. Hepatic histopathology, immunohistochemical analysis of cell proliferation and apoptosis by DNA fragmentation assay were performed. Our results clearly indicate that sulfated polysaccharides of U. lactuca exert a marked chemoprevention of DENA-initiated hepatocarcinogenesis through inhibition of abnormal cell proliferation and induction of apoptosis. A modest inhibition rat liver carcinogenesis was observed with the aqueous extract. The sulfated polysaccharides altered serum parameters of hepatic damage and modulated various components of the hepatic enzymatic and nonenzymatic antioxidant defense systems. The sulfated polysaccharides from U. lactuca may have unique properties of providing protection against DENA-induced oxidative stress which could contribute to chemoprevention of experimental hepatocarcinogenesis. U. lactuca sulfated polysaccharides could be developed as chemopreventive and therapeutic drug against human HCC.

Metabolomics coupled with pattern recognition and pathway analysis on potential biomarkers in liver injury and hepatoprotective effects of yinchenhao

Metabolomics can provide an opportunity to develop the systematic analysis of the metabolites in biological samples and has been increasingly applied to discovering and identifying biomarkers and perturbed pathways. It enables us to better understand the metabolic pathways which can clarify the mechanism of traditional Chinese medicines (TCM). Yinchenhao (YCH, Artemisia annua L), a famous TCM plant, has been used clinically for more than a thousand years to relieve liver diseases in Asia, and its mechanisms are not still completely clear. Here, metabolomic techniques may provide additional insight, and our investigation was designed to assess the effects and possible mechanisms of YCH on α-naphthylisothiocyanate (ANIT)-induced liver injury. Metabolite profiling was performed by ultra-performance liquid chromatography/electrospray ionization quadruple time-of-flight mass spectrometry (UPLC/ESI-Q-TOF/MS) combined with pathway analysis and pattern recognition approaches including independent component analysis (ICA) and partial least squares-discriminant analysis (PLS-DA). Biochemistry test was also performed for the liver tissue and plasma samples. The changes in metabolic profiling were restored to their baseline values after YCH treatment according to the ICA score plots. Of note, YCH has a potential pharmacological effect through regulating multiple perturbed pathways to normal state, correlating well to the assessment of biochemistry test. Five different potential biomarkers in the positive mode contributing to the treatment of YCH were discovered. Pathway analysis showed that these metabolites were associated with perturbations in pyrimidine metabolism, primary bile acid biosynthesis, and propanoate metabolism, which may be helpful to further understand the action mechanisms of YCH. It showed that changed biomarkers and pathways may provide evidence to insight into drug action mechanisms and drug discovery.

Alternations of phospholipid profile in placenta of streptozotocin-induced diabetic rat

Phospholipids have important roles in many biological processes, but their role in fetal malformation in pregnancy in diabetes is unclear. Metabolic fingerprinting of placental phospholipids in pregnant streptozotocin-induced type 1 diabetic rats was performed using Fourier transform-ion cyclotron resonance mass spectrometry. Some of the fetuses from the pregnant diabetic rats exhibited ventricular septal defects. Alterations of phospholipid compositions in the diabetic rat placenta were detected. We suggest that these changes in phospholipids in the diabetic placenta might be involved in development of fetal malformation in a type 1 diabetic pregnancy.

Protective effects of Moutan Cortex Radicis against acute hepatotoxicity

This study evaluated the potential beneficial effect of Moutan Cortex Radicis (MCR) in a murine model of carbon tetrachloride (CCl(4))-, D-galactosamine (GalN)- and α-naphthylisothiocyanate (ANIT)-induced liver injury. Acute hepatotoxicity was induced by intraperitoneal injection of CCl(4) (10 µL/kg), GalN (700 mg/kg), and ANIT (40 mg/kg). Animals received MCR (30, 100, and 300 mg/kg ) orally at 48, 24, and 2 h before and 6 h after administration of CCl(4), GalN, and ANIT. Serum activities of aminotransferase were significantly higher at 24 h after CCl(4) or GalN treatment. These changes were attenuated by MCR. Histopathological analysis revealed multiple and extensive areas of portal inflammation, hepatocellular necrosis, and an increase in inflammatory cell infiltration. These changes were inhibited by MCR. Serum total bilirubin concentration increased and bile flow decreased significantly 48 h after ANIT treatment, which was attenuated by MCR. Our results suggest that MCR has a protective effect on acute liver injury.

Metabolic Fingerprinting in Toxicological Assessment Using FT-ICR MS

Detection of the toxicity of a candidate compound at an early stage of drug development is an emerging area of interest. It is difficult to determine all of the effects of metabolism of a compound using traditional approaches such as histopathology and serum biochemistry. The goal of a metabolomics approach is to determine all metabolites in a living system, with the potential to detect and identify biomarkers involved in toxicity onset. Here, we summarize the metabolic fingerprints for detection and identification of metabolic changes and biomarkers related to drug-induced toxicity using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS).