Plasma lipid profiling of different types of hepatic fibrosis induced by carbon tetrachloride and lomustine in rats

Hepatocyte-Specific Yap1 Knockout Maintained the Liver Homeostasis of Lipid Metabolism in Mice

Introduction

Yes-associated protein 1 (YAP1) is a crucial molecule in the Hippo pathway. The impact of hepatocyte-specific Yap1 knockout (Yap1 LKO) on hepatic lipid droplets (LD) and pePLIN2 in metabolic fatty liver has not been reported. This study aims to explore whether Yap1 LKO could offer a protective effect in a liver injury model.

Methods

Three-week-old Yap1 LKO and Yap1 Flox mice were given aristolochic acid I (AAI) combined carbon tetrachloride (CCL4) establish liver injury model. Eight-week-old Yap1 LKO and Yap1 Flox mice were fed with a high-fat diet for 18 weeks to establish obesity-related liver injury model. Further biochemical, histomorphological, immunohistochemical, and lipidomic analyses were performed on serum and liver tissues of these mice to elucidate the effects of hepatocyte-specific Yap1 knockout on hepatic lipid metabolism.

Results

Yap1 LKO reduced triglyceride (TG) content and PLIN2 expression level in the liver during the intervention of AAI combined CCl4. Moreover, Yap1 LKO improved lipid metabolism homeostasis in the liver by increasing the beneficial lipid molecules and reducing the harmful lipid molecules through lipidomics. Finally, Yap1 LKO reduced TG content in the serum and liver, hepatic vacuolar degeneration, and hepatic PLIN2 expression level in mice fed with a high-fat diet (HFD).

Conclusion

Yap1 LKO is protective in regulating liver and blood TG when induced with toxic substances AAI combined CCl4 and a high-fat diet.

Phosphatidylcholine (18:0/20:4), a potential biomarker to predict ethionamide-induced hepatic steatosis in rats

Ethionamide (ETH), a second-line drug for multi-drug resistant tuberculosis, is known to cause hepatic steatosis in rats and humans. To investigate predictive biomarkers for ETH-induced steatosis, we performed lipidomics analysis using plasma and liver samples collected from rats treated orally with ETH at 30 and 100 mg/kg for 14 days. The ETH-treated rats developed hepatic steatosis with Oil Red O staining-positive vacuolation in the centrilobular hepatocytes accompanied by increased hepatic contents of triglycerides (TG) and decreased plasma TG and total cholesterol levels. A multivariate analysis for lipid profiles revealed differences in each of the 35 lipid species in the plasma and liver between the control and the ETH-treated rats. Of those lipids, phosphatidylcholine (PC) (18:0/20:4) decreased dose-dependently in both the plasma and liver. Moreover, serum TG-rich very low-density lipoprotein (VLDL) levels, especially the large particle fraction of VLDL composed of PC containing arachidonic acid (20:4) involved in hepatic secretion of TG, were decreased dose-dependently. In conclusion, the decreased PC (18:0/20:4) in the liver, possibly leading to suppression of hepatic TG secretion, was considered to be involved in the pathogenesis of the ETH-induced hepatic steatosis. Therefore, plasma PC (18:0/20:4) levels are proposed as mechanism-related biomarkers for ETH-induced hepatic steatosis.

Chemical profile of Swertia mussotii Franch and its potential targets against liver fibrosis revealed by cross-platform metabolomics

ETHNOPHARMACOLOGICAL RELEVANCE

Swertia mussotii Franch (SMF) is a well-known Tibetan medicine for the treatment of liver disease in China. However, the chemical profile and molecular mechanism of SMF against hepatic fibrosis are not yet well explored.

AIM OF THE STUDY

This work aimed to elucidate the chemical profile of SMF and investigate the action mechanisms of SMF against carbon tetrachloride (CCl4)-induced hepatic fibrosis.

MATERIALS AND METHODS

Ultra performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOFMS) and UNIFI platform was firstly employed to reveal the chemical profile of SMF. Cross-platform serum metabolomics based on gas chromatography/liquid chromatography-mass spectrometry were performed to characterize the metabolic fluctuations associated with CCl4-induced hepatic fibrosis in mice and elucidate the underlying mechanisms of SMF. Western blotting was further applied to validate the key metabolic pathways.

RESULTS

A total of 31 compounds were identified or tentatively characterized from SMF. Twenty-seven differential metabolites were identified related with CCl4-induced liver fibrosis, and SMF could significantly reverse the abnormalities of seventeen metabolites. The SMF-reversed metabolites were involved in arachidonic acid metabolism, glycine, serine and threonine metabolism, tyrosine metabolism, arginine and proline metabolism, primary bile acid biosynthesis, glycerophospholipid metabolism and TCA cycle. The results of western blotting analysis showed that SMF could alleviate liver fibrosis by increasing the levels of CYP7A1, CYP27A1 and CYP8B1 and decreasing the level of LPCAT1 to regulate the metabolic disorders of primary bile acid biosynthesis and glycerophospholipid.

CONCLUSION

It could be concluded that primary bile acid biosynthesis and glycerophospholipid metabolism were the two important target pathways for SMF-against liver fibrosis, which provided the theoretical foundation for its clinical use.

Open-flow microperfusion combined with mass spectrometry for in vivo liver lipidomic analysis

At present, conventional microdialysis (MD) techniques cannot efficiently sample lipids in vivo, possibly due to the high mass transfer resistance and/or the serious adsorption of lipids onto the semi-permeable membrane of a MD probe. The in vivo monitoring of lipids could be of great significance for the study of disease development and mechanisms. In this work, an open-flow microperfusion (OFM) probe was fabricated, and the conditions for sampling lipids via OFM were optimized. Using OFM, the recovery of lipid standards was improved to more than 34.7%. OFM is used for the in vivo sampling of lipids in mouse liver tissue with fibrosis, and it is then combined with mass spectrometry (MS) to perform lipidomic analysis. 156 kinds of lipids were identified in the dialysate collected via OFM, and it was found that the phospholipid levels, including PC, PE, and SM, were significantly higher in a liver suffering from fibrosis. For the first time, OFM combined with MS to sample and analyze lipids has provided a promising platform for in vivo lipidomic studies.

Protective effect of picroside I against hepatic fibrosis in mice via sphingolipid metabolism, bile acid biosynthesis, and PPAR signaling pathway

Picroside I, a hepatoprotectant isolated from Picrorhiza kurroa Royle ex Benth and P. scrophulariiflora Pennell, can reduce liver injury in humans and animals. However, its anti-fibrosis effect remains elusive. This work aimed to explore the mechanism underlying the hepatoprotective effect of picroside I against hepatic fibrosis. Male mice (12 mice per group) were randomly divided into six groups: the control group; the model group, which received thioacetamide (TAA); the positive group, which received TAA + S-(5'-adenosyl)-l-methionine (SAMe, 10 mg/kg); the low-dose group, which received TAA + picroside I (25 mg/kg); the middle-dose group, which received TAA + picroside I (50 mg/kg); and the high-dose group, which received TAA + picroside I (75 mg/kg). Serum biochemical indicators were detected, and histological evaluation was performed. Metabolomics and proteomic analyses were conducted via liquid-chromatography coupled with tandem mass spectrometry (LC-MS/MS). Data showed that picroside I could decrease the serum levels of alanine transaminase (ALT), aspartate transaminase (AST), collagen type IV (CIV), N-terminal peptide of type III procollagen (PIIINP), laminin (LN), and hyaluronic acid (HA) and reduced fibrosis area. Picroside I altered metabolomic profiles, including energy, lipid, and glutathione (GSH) metabolism, in ice with fibrosis. Additionally, 25 differentially expressed proteins in the picroside I high-dose-treated group were reversed relative to in the model group. These proteins were involved in the sphingolipid signaling pathway, primary bile acid biosynthesis, and peroxisome proliferator-activated receptor (PPAR) signaling pathway. Moreover, this study revealed how picroside I could protect against TAA-induced liver fibrosis in mice. Results indicated that picroside I can serve as a candidate drug for hepatic fibrosis.

Anthraquinones in the aqueous extract of Cassiae semen cause liver injury in rats through lipid metabolism disorder

BACKGROUND

Cassiae semen has been used as the tea or medicine component to treat hyperlipidemia or for hepatoprotection. However, Cassiae semen was reported to be a potentially hepatotoxic herb, and the underlying hepatotoxicity mechanisms or specific hepatotoxic components of Cassiae semen are unknown.

PURPOSE

In this study, we aimed to explore the potential hepatotoxicity mechanisms and the hepatotoxic components of Cassiae semen.

METHODS

Both young adult male and female SD rats were orally administrated with the aqueous extract of the seeds of Senna obtusifolia (L.) H.S.Irwin & Barneby at doses of 4.73, 15.75, 47.30 g/kg for 28 days, and the body weight, liver coefficient, bile acids, histopathology, serum levels of TC, TG, LDL, HDL, ALP, ALT, AST, and LDH were examined. Lipidomic analysis of rat serum was performed by LC-MS to investigate the specifically changed lipids caused by the aqueous extract treatment. The components absorbed in plasma were detected by UHPLC-Q-Exactive-MS. MTT assay was used to evaluate the cytotoxicity of these components absorbed in plasma.

RESULTS

The serum levels of ALP, AST, ALT, LDH were increased on day 7 with some of which gradually dropped to normal level on day 28. In high dose of the aqueous extract treated group, the histopathological changes were observed based on the cytoplasmic vacuolation in the liver and the increase of bile acids, indicating the hepatotoxicity of the aqueous extract. The changes of TC, TG, LDL, HDL indicated the disorder of lipid metabolism. By comparing the difference in lipids between high dose group and control group, the results showed that the alterations were primarily focused on glycerophospholipid metabolism in both male and female rats. In addition, the glycerolipid metabolism in female rats also changed. Further analyses found that PC (18:2/20:4) and LysoPC 18:0 were significantly increased. Among these phytochemicals detected in plasma, nine components in the aqueous extract were considered to have the highest concentrations, particularly some types of anthraquinones (AQs) existing in Cassiae semen (AQs-in-CS), such as obtusifolin, aurantio-obtusin, and obtusin. The MTT assay showed that emodin, obtusifolin, rhein, aurantio-obtusin, and obtusin inhibited cell viability. Considering plasma concentrations and cytotoxicity of these components, our study indicates that the AQs-in-CS (obtusifolin, aurantio-obtusin and obtusin), emodin and rhein are the potential hepatotoxic phytochemicals in the aqueous extract.

Nutrient mixture from germinated legumes: Enhanced medicinal value with herbs-attenuated liver cirrhosis

Among various food processing strategies, germination and dehulling enhance the nutritional content of the food, and the addition of herbs to this could improve the medicinal value. The milled powders of germinated Macrotyloma uniflorum (horse gram) and Vigna radiata (green gram) were used to make the nutrient mixture. Further, Curcuma longa (turmeric) and Trigonella foenum graecum (fenugreek) were used to improve its medicinal value. The prepared nutrient mixture has high nutritional value, antioxidant potential, and reduced antinutrient factors. Supplementation of nutrient mixture reduced oxidative stress-mediated hepatocyte injury on the CCl₄ -induced liver cirrhosis model. Further, histological examination (H&E and Sirius red), matrix metalloproteinase gelatin zymography, and Western blot revealed the management of hepatic stellate cells in an inactive stage thereby reduced cirrhosis. These findings conclude that the supplementation of nutrient mixture formulation protected and effectively prevented liver cirrhosis. PRACTICAL APPLICATIONS: This study has a good impact on nutritional therapy for liver diseases. Many of the chronic liver diseases are associated with severe malnutrition and hypoalbuminemia, which further worsens the condition. This study would emphasize the nutritional therapy to treat such imbalance and enriching the medicinal value of nutrition mixture with herbs could target different pathophysiological changes and provide better defense in liver disease patients. Since this nutrient mixture is from common edible natural resources, it could reach the pharmaceutical industry's attention to the highest production and marketing.

Lipidomic Profiling Reveals Disruption of Lipid Metabolism in Valproic Acid-Induced Hepatotoxicity

Valproic acid (VPA) is one of the most widely prescribed antiepileptic drugs, as VPA-induced hepatotoxicity is one of the most severe adverse reaction that can lead to death. The objective of this study was to gain an understanding of dysregulated lipid metabolism in mechanism of hepatotoxicity. Nontargeted lipidomics analysis with liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF/MS) was performed to explore differential lipids from the patient serum and L02 cells. Lipidomics data interpretation was augmented by gene expression analyses for the key enzymes in lipid metabolism pathways. From patient serum lipidomics, pronouncedly changed lipid species between abnormal liver function (ALF) patients and normal liver function (NLF) patients were identified. Among these lipid species, LPCs, Cers, and SMs were markedly reduced in the ALF group and showed negative relationships with liver injury severity [alanine aminotransferase (ALT) levels], while significantly increased triacylglycerols (TAG) with higher summed carbon numbers demonstrated a positive relationship with ALT levels. Regarding lipidomics in hepatic L02 cells, TAG was markedly elevated after VPA exposure, especially in TAGs with more than 53 summed carbons. Besides, gene expression analysis revealed dysregulated lipid metabolism in VPA-treated L02 cells. Peroxime proliferators-activated receptor (PPARγ) pathway played an important role in VPA-induced lipid disruption through inducing long-chain fatty acid uptake and TAG synthesis, which was also regulated by Akt pathway. Our findings present that VPA-induced lipid metabolism disruption might lead to lipotoxicity in the liver. This approach is expected to be applicable for other drug-induced toxicity assessments.

Arsenic trioxide, a cancer chemo drug hampers fibrotic liver regeneration by interrupting oxidative stress rekindling and stellate cell rejuvenation

After withdrawal of liver toxic insult, the spontaneous regenerative potential of the liver is well reported in the literature. On the other hand, various molecules have been reported to promote as well as delay such natural regeneration. This current study investigates the involvement of arsenic trioxide (ATO) medication at chemotherapeutic dose on the spontaneous regeneration of the CCl₄ induced fibrotic liver. Liver injury markers, such as albumin and SGOT, SGPT, and ALP activities, in serum indicated that ATO supplementation during liver regeneration hampers the rejuvenation process. The hepatic architecture as well as the degree of fibrosis by hematoxylin and eosin and Sirius red staining confirms the above findings. The reduced hepatic antioxidant system and elevated oxidative stress markers, such as lipid peroxidation and 8-hydroxy deoxy-guanosine-positive hepatocytes in ATO supplied rats, display the persistence of oxidative stress when compared with healthy controls and the normal regeneration model. Immuno-histochemical localization of Ki-67 indicates that mitotically active hepatocytes were fewer in the ATO given rats when compared with normal regeneration rats. Further delay in hepatic fibrinolysis was monitored by matrix metalloproteinase zymography assay in the ATO-given animals. Poly(ADP-ribose) polymerase 1 expression demonstrates elevated hepatocyte apoptosis with ATO. Furthermore, increased α-smooth muscle actin indicates that the stellate cells are in an activated state in ATO supplemented fibrotic animals. In conclusion, it's observed that ATO supplementation to the fibrotic liver delays oxidative stress revitalization and maintains stellate cells in the active form, thereby delaying liver regeneration, and the health status of the liver must be taken into account before administering drugs like ATO.

A Metabolomics Signature Linked To Liver Fibrosis In The Serum Of Transplanted Hepatitis C Patients

Liver fibrosis must be evaluated in patients with hepatitis C virus (HCV) after liver transplantation because its severity affects their prognosis and the recurrence of HCV. Since invasive biopsy is still the gold standard to identify patients at risk of graft loss from rapid fibrosis progression, it becomes crucial the development of new accurate, non-invasive methods that allow repetitive examination of the patients. Therefore, we have developed a non-invasive, accurate model to distinguish those patients with different liver fibrosis stages. Two hundred and three patients with HCV were histologically classified (METAVIR) into five categories of fibrosis one year after liver transplantation. In this cross-sectional study, patients at fibrosis stages F0-F1 (n = 134) were categorised as “slow fibrosers” and F2-F4 (n = 69) as “rapid fibrosers”. Chloroform/methanol serum extracts were analysed by reverse ultra-high performance liquid chromatography coupled to mass spectrometry. A diagnostic model was built through linear discriminant analyses. An algorithm consisting of two sphingomyelins and two phosphatidylcholines accurately classifies rapid and slow fibrosers after transplantation. The proposed model yielded an AUROC of 0.92, 71% sensitivity, 85% specificity, and 84% accuracy. Moreover, specific bile acids and sphingomyelins increased notably along with liver fibrosis severity, differentiating between rapid and slow fibrosers.

Enrichment of resolving power improves ion-peak quantification on a lipidomics platform

In this study, we delineated the importance of MS resolving power on the ion-peak quantification of lipids using an Orbitrap Fusion instrument and established a liquid chromatography-based, high-performance lipidomics platform. The ion-peak recognition of several lipids in human plasma, such as LPC(15:0), LPE(22:5), and PC(35:0), was clearly improved by increasing the MS resolving power. In addition, we evaluated the impact of resolving power on the quantitative detection of lipids by automatic ion-peak recognition with calculation of the coefficient of variance (CV). The extracted ions obtained from human plasma were automatically annotated by Compound Discoverer software with manual confirmation of standards or MS²/MS³ fragments (class- and acyl side chain-specific ions and neutral losses). Quantitative evaluation of 499 lipids in human plasma in terms of their CV values clearly demonstrated an improvement in the quantitative performance by enriching the resolving power. Moreover, we evaluated our new lipidomics platform with enriched MS resolving power (setting of 240,000, full width at half maximum at m/z 200). Because automatic annotation by TraceFinder software overlooks several lipid ions, we further manually annotated additional lipid ions, which were confirmed by standards or MS²/MS³ fragments. Eventually, our platform detected 967 lipids encompassing 34 lipid classes, which were confirmed with standards or MS²/MS³ fragments. Of these lipids, 922 scored <20% of the CV values. Taken together, enriching the resolving power improved ion-peak quantification on our novel lipidomics platform, which enabled us to detect broad-spectrum lipids from human plasma.

Evaluation of the Potential Risk of Drugs to Induce Hepatotoxicity in Human-Relationships between Hepatic Steatosis Observed in Non-Clinical Toxicity Study and Hepatotoxicity in Humans

In the development of drugs, we sometimes encounter fatty change of the hepatocytes (steatosis) which is not accompanied by degenerative change in the liver in non-clinical toxicity studies. In this study, we investigated the relationships between fatty change of the hepatocytes noted in non-clinical toxicity studies of compound X, a candidate compound in drug development, and mitochondrial dysfunction in order to estimate the potential risk of the compound to induce drug-induced liver injury (DILI) in humans. We conducted in vivo and in vitro exploratory studies for this purpose. In vivo lipidomics analysis was conducted to investigate the relationships between alteration of the hepatic lipids and mitochondrial dysfunction. In the liver of rats treated with compound X, triglycerides containing long-chain fatty acids, which are the main energy source of the mitochondria, accumulated. Accumulation of these triglycerides was considered to be related to the inhibition of mitochondrial respiration based on the results of in vitro mitochondria toxicity studies. In conclusion, fatty change of the hepatocytes (steatosis) in non-clinical toxicity studies of drug candidates can be regarded as a critical finding for the estimation of their potential risk to induce DILI in humans when the fatty change is induced by mitochondrial dysfunction.

Arachidonic acid-containing phosphatidylcholine characterized by consolidated plasma and liver lipidomics as an early onset marker for tamoxifen-induced hepatic phospholipidosis

Lipid profiling has emerged as an effective approach to not only screen disease and drug toxicity biomarkers but also understand their underlying mechanisms of action. Tamoxifen, a widely used antiestrogenic agent for adjuvant therapy against estrogen-positive breast cancer, possesses side effects such as hepatic steatosis and phospholipidosis (PLD). In the present study, we administered tamoxifen to Sprague-Dawley rats and used lipidomics to reveal tamoxifen-induced alteration of the hepatic lipid profile and its association with the plasma lipid profile. Treatment with tamoxifen for 28 days caused hepatic PLD in rats. We compared the plasma and liver lipid profiles in treated vs. untreated rats using a multivariate analysis to determine differences between the two groups. In total, 25 plasma and 45 liver lipids were identified and altered in the tamoxifen-treated group. Of these lipids, arachidonic acid (AA)-containing phosphatidylcholines (PCs), such as PC (17:0/20:4) and PC (18:1/20:4), were commonly reduced in both plasma and liver. Conversely, tamoxifen increased other phosphoglycerolipids in the liver, such as phosphatidylethanolamine (18:1/18:1) and phosphatidylinositol (18:0/18:2). We also examined alteration of AA-containing PCs and some phosphoglycerolipids in the pre-PLD stage and found that these lipid alterations were initiated before pathological alteration in the liver. In addition, changes in plasma and liver levels of AA-containing PCs were linearly associated. Moreover, levels of free AA and mRNA levels of AA-synthesizing enzymes, such as fatty acid desaturase 1 and 2, were decreased by tamoxifen treatment. Therefore, our study demonstrated that AA-containing PCs might have potential utility as novel and predictive biomarkers for tamoxifen-induced PLD. Copyright © 2017 John Wiley & Sons, Ltd.