Molecular mechanisms of liver injury: apoptosis or necrosis. ACTA ACUST UNITED AC. 2014;66:351-356. [PMID: 24867271 DOI: 10.1016/j.etp.2014.04.004]

Exposure to acifluorfen induces developmental toxicity in the early life stage of zebrafish

Acifluorfen, a selective herbicide from the diphenyl ether family, targets broad leaf weeds. Diphenyl ether inhibits chlorophyll production in green plants by inhibiting protoporphyrinogen oxidase (PPO), causing cellular damage. Despite its known impacts on plants, the influence of acifluorfen on zebrafish embryo development remains unclear. In this study, we explored the LC50 of acifluorfen in early-stage wild-type zebrafish, determining it to be 54.99 mg/L. Subsequent examinations revealed morphological changes in zebrafish, including reduced body length. Using the cmlc2:dsRED transgenic model, we observed heart dysfunction in acifluorfen-exposed zebrafish, marked by an enlarged heart area, edema, and decreased heart rate. In response to dose-dependent acifluorfen exposure, the inhibition of angiogenesis in the brain was observed in transgenic zebrafish models (fli1a:eGFP). Organ malformations, specifically in the liver and pancreas, were noted, in lfabp:dsRED;elastase:eGFP transgenic models, indicating reduced organ size in acifluorfen-exposed zebrafish. Furthermore, acifluorfen heightened the expression of apoptosis-related genes (casp8, casp9, and tp53) in zebrafish embryos. We then determined whether acifluorfen affected the viability of zebrafish liver (ZFL) cells based on its effects on liver development in vivo. The results indicated that the proliferation of ZFL cells decreased significantly in a dose-dependent manner. Additionally, acifluorfen-treated ZFL cells exhibited a slight increase in apoptotic cells stained with annexin V and propidium iodide. In summary, these findings establish a baseline concentration for acifluorfen's effects on aquatic ecosystems and non-target organisms.

Hybrid non-animal modeling: A mechanistic approach to predict chemical hepatotoxicity

Developing mechanistic non-animal testing methods based on the adverse outcome pathway (AOP) framework must incorporate molecular and cellular key events associated with target toxicity. Using data from an in vitro assay and chemical structures, we aimed to create a hybrid model to predict hepatotoxicants. We first curated a reference dataset of 869 compounds for hepatotoxicity modeling. Then, we profiled them against PubChem for existing in vitro toxicity data. Of the 2560 resulting assays, we selected the mitochondrial membrane potential (MMP) assay, a high-throughput screening (HTS) tool that can test chemical disruptors for mitochondrial function. Machine learning was applied to develop quantitative structure-activity relationship (QSAR) models with 2536 compounds tested in the MMP assay for screening new compounds. The MMP assay results, including QSAR model outputs, yielded hepatotoxicity predictions for reference set compounds with a Correct Classification Ratio (CCR) of 0.59. The predictivity improved by including 37 structural alerts (CCR = 0.8). We validated our model by testing 37 reference set compounds in human HepG2 hepatoma cells, and reliably predicting them for hepatotoxicity (CCR = 0.79). This study introduces a novel AOP modeling strategy that combines public HTS data, computational modeling, and experimental testing to predict chemical hepatotoxicity.

Research progress on rodent models and its mechanisms of liver injury

The liver is the most important organ for biological transformation in the body and is crucial for maintaining the body's vital activities. Liver injury is a serious pathological condition that is commonly found in many liver diseases. It has a high incidence rate, is difficult to cure, and is prone to recurrence. Liver injury can cause serious harm to the body, ranging from mild to severe fatty liver disease. If the condition continues to worsen, it can lead to liver fibrosis and cirrhosis, ultimately resulting in liver failure or liver cancer, which can seriously endanger human life and health. Therefore, establishing an rodent model that mimics the pathogenesis and severity of clinical liver injury is of great significance for better understanding the pathogenesis of liver injury patients and developing more effective clinical treatment methods. The author of this article summarizes common chemical liver injury models, immune liver injury models, alcoholic liver injury models, drug-induced liver injury models, and systematically elaborates on the modeling methods, mechanisms of action, pathways of action, and advantages or disadvantages of each type of model. The aim of this study is to establish reliable rodent models for researchers to use in exploring anti-liver injury and hepatoprotective drugs. By creating more accurate theoretical frameworks, we hope to provide new insights into the treatment of clinical liver injury diseases.

Herpetin Promotes Bone Marrow Mesenchymal Stem Cells to Alleviate Carbon Tetrachloride-Induced Acute Liver Injury in Mice

Herpetin, an active compound derived from the seeds of Herpetospermum caudigerum Wall., is a traditional Tibetan herbal medicine that is used for the treatment of hepatobiliary diseases. The aim of this study was to evaluate the stimulant effect of herpetin on bone marrow mesenchymal stem cells (BMSCs) to improve acute liver injury (ALI). In vitro results showed that herpetin treatment enhanced expression of the liver-specific proteins alpha-fetoprotein, albumin, and cytokeratin 18; increased cytochrome P450 family 3 subfamily a member 4 activity; and increased the glycogen-storage capacity of BMSCs. Mice with ALI induced by carbon tetrachloride (CCl₄) were treated with a combination of BMSCs by tail-vein injection and herpetin by intraperitoneal injection. Hematoxylin and eosin staining and serum biochemical index detection showed that the liver function of ALI mice improved after administration of herpetin combined with BMSCs. Western blotting results suggested that the stromal cell-derived factor-1/C-X-C motif chemokine receptor 4 axis and the Wnt/β-catenin pathway in the liver tissue were activated after treatment with herpetin and BMSCs. Therefore, herpetin is a promising BMSC induction agent, and coadministration of herpetin and BMSCs may affect the treatment of ALI.

Mesenchymal Stem Cell-Derived Exosomes: A Promising Therapeutic Agent for the Treatment of Liver Diseases

Liver disease has become a major global health and economic burden due to its broad spectrum of diseases, multiple causes and difficult treatment. Most liver diseases progress to end-stage liver disease, which has a large amount of matrix deposition that makes it difficult for the liver and hepatocytes to regenerate. Liver transplantation is the only treatment for end-stage liver disease, but the shortage of suitable organs, expensive treatment costs and surgical complications greatly reduce patient survival rates. Therefore, there is an urgent need for an effective treatment modality. Cell-free therapy has become a research hotspot in the field of regenerative medicine. Mesenchymal stem cell (MSC)-derived exosomes have regulatory properties and transport functional "cargo" through physiological barriers to target cells to exert communication and regulatory activities. These exosomes also have little tumorigenic risk. MSC-derived exosomes promote hepatocyte proliferation and repair damaged liver tissue by participating in intercellular communication and regulating signal transduction, which supports their promise as a new strategy for the treatment of liver diseases. This paper reviews the physiological functions of exosomes and highlights the physiological changes and alterations in signaling pathways related to MSC-derived exosomes for the treatment of liver diseases in some relevant clinical studies. We also summarize the advantages of exosomes as drug delivery vehicles and discuss the challenges of exosome treatment of liver diseases in the future.

Weighted Gene Coexpression Network Analysis in Mouse Livers following Ischemia-Reperfusion and Extensive Hepatectomy

In mouse models, the recovery of liver volume is mainly mediated by the proliferation of hepatocytes after partial hepatectomy that is commonly accompanied with ischemia-reperfusion. The identification of differently expressed genes in liver following partial hepatectomy benefits the better understanding of the molecular mechanisms during liver regeneration (LR) with appliable clinical significance. Briefly, studying different gene expression patterns in liver tissues collected from the mice group that survived through extensive hepatectomy will be of huge critical importance in LR than those collected from the mice group that survived through appropriate hepatectomy. In this study, we performed the weighted gene coexpression network analysis (WGCNA) to address the central candidate genes and to construct the free-scale gene coexpression networks using the identified dynamic different expressive genes in liver specimens from the mice with 85% hepatectomy (20% for seven-day survial rate) and 50% hepatectomy (100% for seven-day survial rate under ischemia-reperfusion condition compared with the sham group control mice). The WGCNA combined with Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses pinpointed out the apparent distinguished importance of three gene expression modules: the blue module for apoptotic process, the turquoise module for lipid metabolism, and the green module for fatty acid metabolic process in LR following extensive hepatectomy. WGCNA analysis and protein-protein interaction (PPI) network construction highlighted FAM175B, OGT, and PDE3B were the potential three hub genes in the previously mentioned three modules. This work may help to provide new clues to the future fundamental study and treatment strategy for LR following liver injury and hepatectomy.

A review of surface-enhanced Raman spectroscopy in pathological processes

With the continuous growth of the human population and new challenges in the quality of life, it is more important than ever to diagnose diseases and pathologies with high accuracy, sensitivity and in different scenarios from medical implants to the operation room. Although conventional methods of diagnosis revolutionized healthcare, alternative analytical methods are making their way out of academic labs into clinics. In this regard, surface-enhanced Raman spectroscopy (SERS) developed immensely with its capability to achieve single-molecule sensitivity and high-specificity in the last two decades, and now it is well on its way to join the arsenal of physicians. This review discusses how SERS is becoming an essential tool for the clinical investigation of pathologies including inflammation, infections, necrosis/apoptosis, hypoxia, and tumors. We critically discuss the strategies reported so far in nanoparticle assembly, functionalization, non-metallic substrates, colloidal solutions and how these techniques improve SERS characteristics during pathology diagnoses like sensitivity, selectivity, and detection limit. Moreover, it is crucial to introduce the most recent developments and future perspectives of SERS as a biomedical analytical method. We finally discuss the challenges that remain as bottlenecks for a routine SERS implementation in the medical room from in vitro to in vivo applications. The review showcases the adaptability and versatility of SERS to resolve pathological processes by covering various experimental and analytical methods and the specific spectral features and analysis results achieved by these methods.

Poly(ADP-ribose) Polymerase (PARP) is Critically Involved in Liver Ischemia/reperfusion-injury

BACKGROUND

Poly(ADP-ribose) polymerase (PARP) is a DNA-repairing enzyme activated by extreme genomic stress, and therefore is potently activated in the remnant liver suffering from ischemia after surgical resection. However, the impact of PARP on post-ischemic liver injury has not been elucidated yet.

MATERIALS AND METHODS

We investigated the impact of PARP on murine hepatocyte/liver injury induced by hypoxia/ischemia, respectively.

RESULTS

PJ34, a specific inhibitor of PARP, markedly protected against hypoxia/reoxygenation (H/R)-induced cell death, though z-VAD-fmk, a pan-caspase inhibitor similarly showed the protective effect. PJ34 did not affect H/R-induced caspase activity or caspase-mediated cell death. z-VAD-fmk also did not affect the production of PAR (i.e., PARP activity). Therefore, PARP- and caspase-mediated cell death occurred in a mechanism independent of each other in H/R. H/R immediately induced activation of PARP and cell death afterwards, both of which were suppressed by PJ34 or Trolox, an antioxidant. This suggests that H/R-induced cell death occurred redox-dependently through PARP activation. H/R and OS induced nuclear translocation of apoptosis inducing factor (AIF, a marker of parthanatos) and RIP1-RIP3 interaction (a marker of necroptosis), both of which were suppressed by PJ34. H/R induced PARP-mediated parthanatos and necroptosis redox-dependently. In mouse experiments, PJ34 significantly reduced serum levels of AST, ALT & LDH and areas of hepatic necrosis after liver ischemia/reperfusion, similar to z-VAD-fmk or Trolox.

CONCLUSION

PARP, activated by ischemic damage and/or oxidative stress, may play a critical role in post-ischemic liver injury by inducing programmed necrosis (parthanatos and necroptosis). PARP inhibition may be one of the promising strategies against post-ischemic liver injury.

Plasma Kallikrein as a Modulator of Liver Injury/Remodeling

The occurrence and persistence of hepatic injury which arises from cell death and inflammation result in liver disease. The processes that lead to liver injury progression and resolution are still not fully delineated. The plasma kallikrein-kinin system (PKKS) has been shown to play diverse functions in coagulation, tissue injury, and inflammation, but its role in liver injury has not been defined yet. In this study, we have characterized the role of the PKKS at various stages of liver injury in mice, as well as the direct effects of plasma kallikrein on human hepatocellular carcinoma cell line (HepG2). Histological, immunohistochemical, and gene expression analyses were utilized to assess cell injury on inflammatory and fibrotic factors. Acute liver injury triggered by carbon tetrachloride (CCl₄) injection resulted in significant upregulation of the plasma kallikrein gene (Klkb1) and was highly associated with the high mobility group box 1 gene, the marker of cell death (r = 0.75, p < 0.0005, n = 7). In addition, increased protein expression of plasma kallikrein was observed as clusters around necrotic areas. Plasma kallikrein treatment significantly increased the proliferation of CCl₄-induced HepG2 cells and induced a significant increase in the gene expression of the thrombin receptor (protease activated receptor-1), interleukin 1 beta, and lectin–galactose binding soluble 3 (galectin-3) (p < 0.05, n = 4). Temporal variations in the stages of liver fibrosis were associated with an increase in the mRNA levels of bradykinin receptors: beta 1 and 2 genes (p < 0.05; n = 3–10). In conclusion, these findings indicate that plasma kallikrein may play diverse roles in liver injury, inflammation, and fibrosis, and suggest that plasma kallikrein may be a target for intervention in the states of liver injury.

The Effect of NeuroAid (MLC901) on Cholestasis-Induced Spatial Memory Impairment with Respect to the Expression of BAX, BCL-2, BAD, PGC-1α and TFAM Genes in the Hippocampus of Male Wistar Rats

Cholestasis is a bile flow reduction that is induced following Bile Duct Ligation (BDL). Cholestasis impairs memory and induces apoptosis. Apoptosis consists of two pathways: intrinsic and extrinsic. The intrinsic pathway is modulated by BCL-2 (B cell lymphoma-2) family proteins. BCL-2 (a pro-survival BCL-2 protein) has anti-apoptotic effect, while BAD (BCL-2-associated death) and BAX (BCL-2-associated X), the other members of BCL-2 family have pro-apoptotic effect. Furthermore, TFAM (mitochondrial transcriptional factor A) is involved in transcription and maintenance of mitochondrial DNA and PGC-1α (peroxisome proliferator-activated receptor γ coactivator-1α) is a master regulator of mitochondrial biogenesis. On the other hand, NeuroAid is a Traditional Chinese Medicine with neuroprotective and anti-apoptosis effects. In this study, we evaluated the effect of cholestasis on spatial memory and expression of BCL-2, BAD, BAX, TFAM, and PGC-1α in the hippocampus of rats. Additionally, we assessed the effect of NeuroAid on cholestasis-induced cognitive and genetic alterations. Cholestasis was induced by BDL surgery and NeuroAid was injected intraperitoneal at the dose of 0.4 mg/kg. Furthermore, spatial memory was evaluated using Morris Water Maze (MWM) apparatus. The results showed cholestasis impaired spatial memory, increased the expression of BAD and BAX, decreased the expression of TFAM and PGC-1α, and did not alter the expression of BCL-2. Also, NeuroAid decreased the expression of BAD and BAX and increased the expression of TFAM, PGC-1α, and BCL-2. In conclusion, cholestasis impaired spatial memory and increased the expression of pro-apoptotic genes. Also, cholestasis decreased the expression of TFAM and PGC-1α. Interestingly, NeuroAid restored the effects of cholestasis.

Pyrazolo[3,4-d]pyrimidine Tyrosine Kinase Inhibitors Induce Oxidative Stress in Patient-Derived Glioblastoma Cells

Background: Glioblastoma (GBM) highly expresses Src tyrosine kinase involved in survival, proliferation, angiogenesis and invasiveness of tumor cells. Src activation also reduces reactive oxygen species (ROS) generation, whereas Src inhibitors are able to increase cellular ROS levels. Methods: Pro-oxidative effects of two pyrazolo[3,4-d]pyrimidine derivatives—Src tyrosine kinase inhibitors, Si306 and its prodrug pro-Si306—were investigated in human GBM cells U87 and patient-derived GBM-6. ROS production and changes in mitochondrial membrane potential were assessed by flow cytometry. The expression levels of superoxide dismutase 1 (SOD1) and 2 (SOD2) were studied by Western blot. DNA damage, cell death induction and senescence were also examined in GBM-6 cells. Results: Si306 and pro-Si306 more prominently triggered ROS production and expression of antioxidant enzymes in primary GBM cells. These effects were followed by mitochondrial membrane potential disruption, double-strand DNA breaks and senescence that eventually led to necrosis. Conclusion: Src kinase inhibitors, Si306 and pro-Si306, showed significant pro-oxidative potential in patient-derived GBM cells. This feature contributes to the already demonstrated anti-glioblastoma properties of these compounds in vitro and in vivo and encourages clinical investigations.

Feasibility of using tissue autolysis to estimate the postmortem interval in horses

Estimation of the postmortem interval (PMI) is a poorly studied field in veterinary pathology. The development of field-applicable methods is needed given that animal cruelty investigations are increasing continually. We evaluated various histologic criteria in equine brain, liver, and muscle tissue to aid the estimation of PMI in horses, which is central to forensic investigations of suspicious death. After death, autolysis proceeds predictably, depending on environmental conditions. Currently, no field-applied methods exist that accurately estimate the PMI using histology in animals or humans through quantification of autolysis. Brain, liver, and skeletal muscle from 12 freshly euthanized horses were held at 22°C and 8°C for 72 h. Tissues were sampled at T0h, T1h, T2h, T4h, T6h, T12h, T24h, T36h, T48h, T60h, and T72h. For each tissue, we quantified 5 to 7 criteria associated with autolysis, based on the percentage of microscopic field involved. Each criterion was modeled, with temperature and time as independent variables. Changes were most predictable in liver and muscle over the first 72 h postmortem. The criteria for autolysis that were present most extensively at both temperatures were hepatocyte individualization and the separation of bile duct epithelium from the basement membrane. The changes that were present next most extensively were disruption of myofiber continuity, hypereosinophilia, and loss of striation. Brain changes were highly variable. The high statistical correlation between the parameter "autolysis" and the variables "time/temperature", indicates that autolysis is progressive and predictable. Further investigation of these criteria is needed to establish histologic algorithms for PMI.

PORIMIN: The key to (+)-Usnic acid-induced liver toxicity and oncotic cell death in normal human L02 liver cells

ETHNOPHARMACOLOGICAL RELEVANCE

Usnic acid (UA) is one of the well-known lichen metabolites that induces liver injury. It is mainly extracted from Usnea longissima and U. diffracta in China or from other lichens in other countries. U. longissima has been used as traditional Chinese medicine for treatment of cough, pain, indigestion, wound healing and infection. More than 20 incidences with hepatitis and liver failure have been reported by the US Food and Drug Administration since 2000. UA is an uncoupler of oxidative phosphorylation causing glutathione and ATP depletion. Previous histological studies observed extensive cell and organelle swellings accompanied with hydrotropic vacuolization of hepatocytes.

AIM OF THE STUDY

This study was to investigate the mechanism of UA-induced liver toxicity in normal human L02 liver cells and ICR mice using various techniques, such as immunoblotting and siRNA transfection.

MATERIALS AND METHODS

Assays were performed to evaluate the oxidative stress and levels of GSH, MDA and SOD. Double flouresencence staining was used for the detection of apoptotic cell death. The protein expressions, such as glutathione S transferase, glutathione reductase, glutathione peroxidase 4, catalase, c-Jun N-terminal protein kinase, caspases, gastamin-D and porimin were detected by Western blotting. Comparisons between transfected and non-transfected cells were applied for the elucidation of the role of porimin in UA-induced hepatotoxicity. Histopathological examination of mice liver tissue, serum total bilirubin and hepatic enzymes of alanine aminotransferase and aspatate aminotransferase were also studied.

RESULTS

The protein expressions of glutathione reductase, glutathione S transferase and glutathione peroxidase-4 were increased significantly in normal human L02 liver cells. Catalase expression was diminished in dose-dependent manner. Moreover, (+)-UA did not induce the activation of caspase-3, caspase-1 or gasdermin-D. No evidence showed the occurrence of pyroptosis. However, the porimin expressions were increased significantly. In addition, (+)-UA caused no cytotoxicity in the porimin silencing L02 cells.

CONCLUSIONS

In conclusion, (+)-UA induces oncotic L02 cell death via increasing protein porimin and the formation of irreversible membrane pores. This may be the potential research area for future investigation in different aspects especially bioactivity and toxicology.

Integrating non-targeted metabolomics and toxicology networks to study the mechanism of Esculentoside A-induced hepatotoxicity in rats

Esculentoside A (EsA) is a kind of triterpenoid saponins from the root tuber of Phytolacca acinosa Roxb. It has extensive medicinal activity, such as antibacterial, anti-inflammatory, immune regulation, and cell proliferation inhibition. However, some researches suggested that EsA can cause hepatotoxicity, whose mechanism is not precise. To ensure the safety and reliability in the clinical use of Phytolacca acinosa Roxb., it is necessary to establish a rapid and accurate method to evaluate the toxicity, analyze and verify the toxicity mechanism of EsA. Therefore, this research explored the mechanism of hepatotoxicity induced by EsA in rats and analyzed endogenous metabolites' changes in rat plasma by combining network toxicology with non-targeted metabolomics. We obtained 58 critical targets of EsA induced hepatotoxicity in rats based on the strategy of network toxicology, including albumin, mitogen-activated protein kinase 1, Caspase-3, etc. Many important pathways were obtained by Kyoto Encyclopedia of Genes and Genomes enrichment analysis, such as HIF-1 signaling pathway, TNF signaling pathway, IL-17 signaling pathway, and other concerning pathways. Sixteen biomarkers, including 5-hydroxykynurenamine, N-acetylserotonin, palmitic acid, etc., were screened from rat plasma using Ultra-performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS), mainly involve Glycerophospholipid metabolism, Tryptophan metabolism, and other metabolic pathways. Further analysis showed that EsA may induce liver injury by activating oxidative stress and energy metabolism disorders, triggering inflammation and apoptosis.

Concentration- and Time-Dependent Effects of Benzalkonium Chloride in Human Lung Epithelial Cells: Necrosis, Apoptosis, or Epithelial Mesenchymal Transition

Benzalkonium chloride (BAC), an antimicrobial agent in inhalable medications and household sprays, has been reported to be toxic to pulmonary organs. Although cell membrane damage has been considered as the main cytotoxic mechanism of BAC, its concentration- and time-dependent cellular effects on lung epithelium have not been fully understood. In the present study, human lung epithelial (H358) cells were exposed to 0.2–40 μg/mL of BAC for 30 min or 21 days. Cell membranes were rapidly disrupted by 30 min exposure, but 24 h incubation of BAC (4–40 μg/mL) predominantly caused apoptosis rather than necrosis. BAC (2–4 μg/mL) induced mitochondrial depolarization, which may be associated with increased expression of pro-apoptotic proteins (caspase-3, PARP, Bax, p53, and p21), and decreased levels of the anti-apoptotic protein Bcl-2. The protein expression levels of IRE1α, BiP, CHOP, and p-JNK were also elevated by BAC (2–4 μg/mL) suggesting the possible involvement of endoplasmic reticulum stress in inducing apoptosis. Long-term (7–21 days) incubation with BAC (0.2–0.6 μg/mL) did not affect cell viability but led to epithelial-mesenchymal transition (EMT) as shown by the decrease of E-cadherin and the increase of N-cadherin, fibronectin, and vimentin, caused by the upregulation of EMT transcription factors, such as Snail, Slug, Twist1, Zeb1, and Zeb2. Therefore, we conclude that apoptosis could be an important mechanism of acute BAC cytotoxicity in lung epithelial cells, and chronic exposure to BAC even at sub-lethal doses can promote pulmonary EMT.

Yinchenhao decoction attenuates obstructive jaundice-induced liver injury and hepatocyte apoptosis by suppressing protein kinase RNA-like endoplasmic reticulum kinase-induced pathway

BACKGROUND

Chronic biliary obstruction results in ischemia and hypoxia of hepatocytes, and leads to apoptosis. Apoptosis is very important in regulating the homeostasis of the hepatobiliary system. Endoplasmic reticulum (ER) stress is one of the signaling pathways that induce apoptosis. Moreover, the protein kinase RNA-like endoplasmic reticulum kinase (PERK)-induced apoptotic pathway is the main way; but its role in liver injury remains unclear. Yinchenhao decoction (YCHD) is a traditional Chinese medicine formula that alleviates liver injury and apoptosis, yet its mechanism is unknown. We undertook this study to investigate the effects of YCHD on the expression of ER stress proteins and hepatocyte apoptosis in rats with obstructive jaundice (OJ).

AIM

To investigate whether YCHD can attenuate OJ-induced liver injury and hepatocyte apoptosis by inhibiting the PERK-CCAAT/enhancer-binding protein homologous protein (CHOP)-growth arrest and DNA damage-inducible protein 34 (GADD34) pathway and B cell lymphoma/leukemia-2 related X protein (Bax)/B cell lymphoma/leukemia-2 (Bcl-2) ratio.

METHODS

For in vivo experiments, 30 rats were divided into three groups: control group, OJ model group, and YCHD-treated group. Blood was collected to detect the indicators of liver function, and liver tissues were used for histological analysis. For in vitro experiments, 30 rats were divided into three groups: G1, G2, and G3. The rats in group G1 had their bile duct exposed without ligation, the rats in group G2 underwent total bile duct ligation, and the rats in group G3 were given a gavage of YCHD. According to the serum pharmacology, serum was extracted and centrifuged from the rat blood to cultivate the BRL-3A cells. Terminal deoxynucleotidyl transferase mediated dUTP nick end-labelling (TUNEL) assay was used to detect BRL-3A hepatocyte apoptosis. Alanine aminotransferase (ALT) and aspartate transaminase (AST) levels in the medium were detected. Western blot and quantitative real-time polymerase chain reaction (qRT-PCR) analyses were used to detect protein and gene expression levels of PERK, CHOP, GADD34, Bax, and Bcl-2 in the liver tissues and BRL-3A cells.

RESULTS

Biochemical assays and haematoxylin and eosin staining suggested severe liver function injury and liver tissue structure damage in the OJ model group. The TUNEL assay showed that massive BRL-3A rat hepatocyte apoptosis was induced by OJ. Elevated ALT and AST levels in the medium also demonstrated that hepatocytes could be destroyed by OJ. Western blot or qRT-PCR analyses showed that the protein and mRNA expression levels of PERK, CHOP, and GADD34 were significantly increased both in the rat liver tissue and BRL-3A rat hepatocytes by OJ. The Bax and Bcl-2 levels were increased, and the Bax/Bcl-2 ratio was also increased. When YCHD was used, the PERK, CHOP, GADD34, and Bax levels quickly decreased, while the Bcl-2 levels increased, and the Bax/Bcl-2 ratio decreased.

CONCLUSION

OJ-induced liver injury and hepatocyte apoptosis are associated with the activation of the PERK-CHOP-GADD34 pathway and increased Bax/Bcl-2 ratio. YCHD can attenuate these changes.

Pelargonidin ameliorates acetaminophen-induced hepatotoxicity in mice by inhibiting the ROS-induced inflammatory apoptotic response

The common analgesic acetaminophen (N-acetyl-p-aminophenol, APAP) is non-toxic to the liver at therapeutic doses. However, an overdose of APAP can lead to APAP-induced liver failure, which has emerged as a serious issue in the US and Europe. Pelargonidin is an anthocyanidin found in pomegranates, plums, and various berries. Pelargonidin has strong antioxidant effects, directly scavenging superoxide radicals and inhibiting H₂O₂-induced lipid peroxidation. Focusing on these effects, we studied the preventative effect of pelargonidin on APAP-induced hepatotoxicity and its underlying mechanisms in vivo. We observed that pelargonidin mitigates serum alanine aminotransferase and aspartate aminotransferase activity, which are strongly associated with APAP-induced hepatotoxicity. We also found that pelargonidin reduced APAP-induced hepatic necrosis by removing excessive ROS. Hepatic necrosis stimulates the release of molecular pathogens that induce inflammation, which increases cell stress and can lead to apoptosis. Therefore, pelargonidin was able to reduce levels of necrosis, inflammation, and hepatocyte apoptosis. These results indicate that the administration of pelargonidin protects against APAP-induced hepatotoxicity and that it could be a novel protective strategy against APAP-induced liver failure.

Ascorbic acid and retinol palmitate modulatory effect on omeprazole-induced oxidative damage, and the cytogenetic changes in S. cerevisiae and S180 cells

Omeprazole (OM), a prototype proton pump inhibitor, oxidizes thiol groups and induces DNA damage. The aim of this study was to evaluate the oxidative effects of omeprazole and its interactions with ascorbic acid (AA, 50 μM) and retinol palmitate (RP) in proficient and deficient Saccharomyces cerevisiae strains, as well as levels of cytogenetic damage in Sarcoma 180 (S180) cells. Omeprazole was tested at concentrations of 10, 20 and 40 μg/mL, whereas H₂O₂ (10 mM), cyclophosphamide (20 mg/mL), and saline (0.9% NaCl solution) were employed as stressor, positive control, and negative control, respectively. Results revealed that omeprazole concentration-dependently induces oxidative effects in S. cerevisiae strains. However, omeprazole co-treated with ascorbic acid (50 μM) and retinol palmitate (100 IU) significantly modulated the oxidative damage inflected on the S. cerevisiae strains. Furthermore, omeprazole did not produce micronucleus formation and chromosomal bridges in S180 cells, but induced shoots. Significant increase in karyolysis and karyorrhexis were also observed with the omeprazole treated groups, which was modulated by co-treatment with ascorbic acid and retinol palmitate. Taken all together, it is suggested that ascorbic acid and retinol palmitate can substantially modulate the oxidative damage caused by omeprazole on the S. cerevisiae strains, however, much precaution is recommended with omeprazole and antioxidant co-treatment.

Triclosan-induced liver injury in zebrafish (Danio rerio) via regulating MAPK/p53 signaling pathway

Long-term exposure of triclosan (TCS), an important antimicrobial agent, can lead to deleterious effects on liver growth and development. However, the related mechanisms on TCS-induced hepatocyte injury remain unclear. Herein, we found that after long-time TCS exposure to adult zebrafish (Danio rerio) from 6 hpf (hours post-fertilization) to 90 dpf (days post-fertilization), the body weight and hepatic weight were significantly increased in concomitant with a large amount of lipid droplet accumulation in liver. Also, TCS exposure resulted in occurrence of oxidative stress by increasing the concentrations of malondialdehyde and reducing the activity of superoxide dismutase both in zebrafish larvae (120 hpf) and adult liver. By H&E staining, we observed a series of abnormal phenomena such as severely hepatocellular atrophy and necrosis, as well as prominently increased hepatic plate gap in TCS-exposure treatment groups. Through AO staining, TCS induced obvious apoptosis in larval heart and liver; through TUNEL assay, a concentration-dependent apoptosis was found to mainly occur in adult liver and its surrounding tissues. The mRNA and protein expression of anti-apoptotic protein Bcl-2 decreased, while that of pro-apoptosis protein Bax significantly increased, identifying that liver injury was closely related to hepatocyte apoptosis. The significant up-regulation of MAPK and p53 at both mRNA and protein levels proved that TCS-induced hepatocyte apoptosis was closely related to activating the MAPK/p53 signaling pathway. These results strongly suggest that long-term TCS-exposure may pose a great injury to zebrafish liver development by means of activating MAPK/p53 apoptotic signaling pathway, also lay theoretical foundation for further assessing TCS-induced ecological healthy risk.

Regulation of TBBPA-induced oxidative stress on mitochondrial apoptosis in L02 cells through the Nrf2 signaling pathway

Tetrabromobisphenol A (TBBPA) is a commonly used brominated flame retardant, which has a wide range of toxic effects on organisms. This study investigated the cytotoxic effects on human hepatocytes (L02 cells) after treated with 0, 5, 10, 20, and 40 μM of TBBPA. Results showed that TBBPA significantly increased intracellular reactive oxygen species (ROS), malondialdehyde (MDA) and the ratio of oxidized/reduced glutathione (GSSG/GSH) dose-dependently. TBBPA also decreased the cell mitochondrial membrane potential (MMP), caused the release of cytochrome C (Cyt C) to cytoplasm and promoted the expression of caspase-9 and caspase-3, and finally increased the level of apoptosis. The ROS inhibitor N-acetyl-L-cysteine (NAC) relieved the oxidative stress responses, and prevented the decrease of MMP and increase of apoptosis. In addition, TBBPA promoted the expression of antioxidant genes related to Nrf2, such as quinone oxidoreductase 1 (NQO1), catalase (CAT), and heme oxygenase 1 (HO-1). Oxidative stress initiated by TBBPA, activated mitochondrial apoptosis and Nrf2 pathway, and increased the degree of apoptosis in L02 cells.

Protective Effects of Costunolide Against D-Galactosamine and Lipopolysaccharide-Induced Acute Liver Injury in Mice

Costunolide, a sesquiterpene isolated from Vladimiria souliei (Franch.) Ling, is known to exhibit anti-inflammatory, anti-viral, and anti-tumor activities. However, the effects of costunolide on liver injury are poorly understood. The current study aimed to investigate the hepatoprotective effects of costunolide against lipopolysaccharide (LPS) and D-galactosamine-induced acute liver injury (ALI) in mice. The results indicated that costunolide (40 mg/kg) could significantly improve the pathological changes of hepatic tissue, and reduced the LPS and D-galactosamine-induced increases of alanine aminotransferase (from 887.24 ± 21.72 to 121.67 ± 6.56 IU/L) and aspartate aminotransferase (from 891.01 ± 45.24 to 199.94 ± 11.53 IU/L) activities in serum. Further research indicated that costunolide significantly reduced malondialdehyde content (from 24.56 ± 1.39 to 9.17 ± 0.25 nmol/ml) and reactive oxygen species (from 203.34 ± 7.68 to 144.23 ± 7.12%), increased the activity of anti-oxidant enzymes superoxide dismutase (from 153.74 ± 10.33 to 262.27 ± 8.39 U/ml), catalase (from 6.12 ± 0.30 to 12.44 ± 0.57 U/ml), and total anti-oxidant capacity (from 0.64 ± 0.06 to 6.29 ± 0.11 U/ml) in hepatic tissues. Western blot results revealed that costunolide may trigger the anti-oxidative defense system by inhibiting kelch-like ECH-associated protein 1 and nuclear factor-related factor 2 (cytosol), increasing nuclear factor-related factor 2 (nucleus), heme oxygenase-1 and NAD (P) H quinone oxidoreductase 1 activity. Moreover, costunolide significantly decreased the protein expression of proinflammatory cytokines including interleukin 1β, interleukin 6, and tumor necrosis factor. Pretreatment with costunolide could reduce the expression of toll-like receptor 4, myeloid differentiation factor 88, p65 (Nucleus), phosphorylated IκB kinase α/β, inhibitor of nuclear factor kappa-B kinase, inhibitor kappa Bα and prevent the expression of phosphorylated inhibitor kappa B kinase which repressed translocation of p65 from cytoplasm to nucleus. In addition, pretreatment with costunolide also inhibited hepatocyte apoptosis by reducing the expression of B-cell lymphoma 2 associated X, cytochrome C, cysteinyl aspartate specific proteinase 3, cysteinyl aspartate specific proteinase 8 and cysteinyl aspartate specific proteinase 9, and by increasing B-cell lymphoma 2. From the above analysis, the protective effects of costunolide against LPS and D-galactosamine-induced ALI in mice may be attributed to its anti-oxidative activity in nuclear factor-related factor 2 signaling pathways, anti-inflammatory suppression in nuclear factor-kappa B signaling pathways, and inhibition of hepatocyte apoptosis. Thus, costunolide may be a potential therapeutic agent in attenuating LPS and D-galactosamine -induced ALI in the future.

Sagittaria sagittifolia polysaccharide protects against isoniazid- and rifampicin-induced hepatic injury via activation of nuclear factor E2-related factor 2 signaling in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The Sagittaria sagittifolia L. polysaccharide (SSP) is a purified form of a homogeneous polysaccharide isolated from the root tubers of S. sagittifolia, which has been used as a protectant against hepatotoxicity induced by coadministration of isoniazid and rifampicin. However, the protective effect of SSP against isoniazid- and rifampicin-induced liver injury has never been studied.

AIM OF THE STUDY

In this study, the hepatoprotective effect of SSP and its underlying mechanism were investigated in mice with isoniazid- and rifampicin-induced liver injury.

MATERIALS AND METHODS

Liver injury was induced in mice by intragastric administration of isoniazid and rifampicin, and the mice were divided into the following six groups: standard control (administration of saline by gavage), model (intragastric administration of isoniazid and rifampicin at 100 mg/kg/day each), positive control (100 mg/kg/day silymarin by gavage 4 h after isoniazid and rifampicin administration), and SSP-treated (200, 400, or 800 mg/kg/day SSP by gavage after isoniazid and rifampicin administration). Subsequently, blood and liver samples were collected from all the animals and were assessed.

RESULTS

SSP significantly alleviated the liver injury, as evidenced by decreased activities of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase in the serum and a decreased level of malondialdehyde in the liver, as well as by an increased level of glutathione and increased activities of superoxide dismutase and catalase in the liver. SSP also effectively reduced the pathological tissue damage. The gene and protein expression of cytochrome P450 (CYP) 2E1 and CYP3A4 was inhibited by SSP. The gene and protein expression of nuclear factor erythroid 2-related factor 2 (NRF2), glutamate-cysteine ligase, and heme oxygenase-1 were induced by SSP, whereas that of Kelch-like ECH-associated protein 1 was inhibited.

CONCLUSIONS

SSP exerts a protective effect against isoniazid- and rifampicin-induced liver injury in mice. The underlying mechanisms may involve activation of NRF2 and its target antioxidant enzymes and inhibition of the expression of CYPs.

Apoptosis and necroptosis in the liver: a matter of life and death

Cell death represents a basic biological paradigm that governs outcomes and long-term sequelae in almost every hepatic disease condition. Acute liver failure is characterized by massive loss of parenchymal cells but is usually followed by restitution ad integrum. By contrast, cell death in chronic liver diseases often occurs at a lesser extent but leads to long-term alterations in organ architecture and function, contributing to chronic hepatocyte turnover, the recruitment of immune cells and activation of hepatic stellate cells. These chronic cell death responses contribute to the development of liver fibrosis, cirrhosis and cancer. It has become evident that, besides apoptosis, necroptosis is a highly relevant form of programmed cell death in the liver. Differential activation of specific forms of programmed cell death might not only affect outcomes in liver diseases but also offer novel opportunities for therapeutic intervention. Here, we summarize the underlying molecular mechanisms and open questions about disease-specific activation and roles of programmed cell death forms, their contribution to response signatures and their detection. We focus on the role of apoptosis and necroptosis in acute liver injury, nonalcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH) and liver cancer, and possible translations into clinical applications.

Chemical induction of hepatic apoptosis in rodents

The urge of identifying new pharmacological interventions to prevent or attenuate liver injury is of critical importance and needs an expanded experimental toolbox. Hepatocyte injury and cellular death is a prominent feature behind the pathology of liver diseases. Several research activities focused on identifying chemicals and hepatotoxicants that induce cell death by apoptosis, in addition to presenting its corresponding signaling pathway. Although such efforts provided further understanding of the mechanisms of cell death, it has also raised confusion concerning identifying the involvement of several modes of cell death including apoptosis, necrosis and fibrosis. The current review highlights the ability of several chemicals and potential hepatotoxicants to induce liver damage in rodents by means of apoptosis while the probable involvement of other modes of cell death is also exposed. Thus, several chemical substances including hepatotoxins, mycotoxins, hyperglycemia inducers, metallic nanoparticles and immunosuppressant drugs are reviewed to explore the hepatic cytotoxic spectrum they could exert on hepatocytes of rodents. In addition, the current review address the mechanism by which hepatotoxicity is initiated in hepatocytes in different rodents aiding the researcher in choosing the right animal model for a better research outcome.

T Cells and Regulated Cell Death: Kill or Be Killed

Cell death plays two major complementary roles in T cell biology: mediating the removal of cells that are targeted by T cells and the removal of T cells themselves. T cells serve as major actors in the adaptive immune response and function by selectively killing cells which are infected or dysfunctional. This feature is highly involved during homeostatic maintenance, and is relied upon and modulated in the context of cancer immunotherapy. The vital recognition and elimination of both autoreactive T cells and cells which are unable to recognize threats is a highly selective and regulated process. Moreover, detection of potential threats will result in the activation and expansion of T cells, which on resolution of the immune response will need to be eliminated. The culling of these T cells can be executed via a multitude of cell death pathways which are used in context-specific manners. Failure of these processes may result in an accumulation of misdirected or dysfunctional T cells, leading to complications such as autoimmunity or cancer. This review will focus on the role of cell death regulation in the maintenance of T cell homeostasis, as well as T cell-mediated elimination of infected or dysfunctional cells, and will summarize and discuss the current knowledge of the cellular mechanisms which are implicated in these processes.

Cellular crosstalk mediated by platelet-derived growth factor BB and transforming growth factor β during hepatic injury activates hepatic stellate cells

Apoptotic hepatocytes release factors that activate hepatic stellate cells (HSCs), thereby inducing hepatic fibrosis. In the present study, in vivo and in vitro injury models were established using acetaminophen, ethanol, carbon tetrachloride, or thioacetamide. Histology of hepatotoxicant-induced diseased hepatic tissue correlated with differential expression of fibrosis-related genes. A marked increase in co-staining of transforming growth factor β receptor type II (TGFRIIβ) – desmin or α-smooth muscle actin – platelet-derived growth factor receptor β (PDGFRβ), markers of activated HSCs, in liver sections of these hepatotoxicant-treated mice also depicted an increase in Annexin V – cytokeratin expressing hepatocytes. To understand the molecular mechanisms of disease pathology, in vitro experiments were designed using the conditioned medium (CM) of hepatotoxicant-treated HepG2 cells supplemented to HSCs. A significant increase in HSC proliferation, migration, and expression of fibrosis-related genes and protein was observed, thereby suggesting the characteristics of an activated phenotype. Treating HepG2 cells with hepatotoxicants resulted in a significant increase in mRNA expression of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor β (TGFβ). CM supplemented to HSCs resulted in increased phosphorylation of PDGFRβ and TGFRIIβ along with its downstream effectors, extracellular signal-related kinase 1/2 and focal adhesion kinase. Neutralizing antibodies against PDGF-BB and TGFβ effectively perturbed the hepatotoxicant-treated HepG2 cell CM-induced activation of HSCs. This study suggests PDGF-BB and TGFβ as potential molecular targets for developing anti-fibrotic therapeutics.

Cytotoxicity of Air Pollutant 9,10-Phenanthrenequinone: Role of Reactive Oxygen Species and Redox Signaling

Atmospheric pollution has been a principal topic recently in the scientific and political community due to its role and impact on human and ecological health. 9,10-phenanthrenequinone (9,10-PQ) is a quinone molecule found in air pollution abundantly in the diesel exhaust particles (DEP). This compound has studied extensively and has been shown to develop cytotoxic effects both in vitro and in vivo. 9, 10-PQ has been proposed to play a critical role in the development of cytotoxicity via generation of reactive oxygen species (ROS) through redox cycling. This compound also reduces expression of glutathione (GSH), which is critical in Phase II detoxification reactions. Understanding the underlying cellular mechanisms involved in cytotoxicity can allow for the development of therapeutics designed to target specific molecules significantly involved in the 9,10-PQ-induced ROS toxicity. This review highlights the developments in the understanding of the cytotoxic effects of 9, 10-PQ with special emphasis on the possible mechanisms involved.

CXCL16 deficiency attenuates acetaminophen-induced hepatotoxicity through decreasing hepatic oxidative stress and inflammation in mice

Chemokine C-X-C ligand 16 (CXCL16), a single-pass Type I membrane protein belonging to the CXC chemokine family, is related to the inflammatory response in liver injury. In present study, we investigated the pathophysiological role of CXCL16, a unique membrane-bound chemokine, in acetaminophen (APAP)-induced hepatotoxicity in mice. Mice were injected with APAP, and blood and tissue samples were harvested at different time points. The serum high-mobility group box 1 and CXCL16 levels were quantified by sandwich immunoassays. The liver tissue sections were stained with hematoxylin-eosin or with dihydroethidium staining. The expressions of CXCL16 and other cytokines were examined by real-time polymerase chain reaction. Ly6-B, p-jun N-terminal kinase (p-JNK), and JNK expressions were measured by western blot analysis. Intracellular glutathione, reactive oxygen species, and malondialdehyde levels were also measured. APAP overdose increased hepatic CXCL16 mRNA and serum CXCL16 protein levels. CXCL16-deficient mice exhibited significantly less liver injury and hepatic necrosis, as well as a lower mortality than wild-type (WT) mice in response to APAP-overdose treatment. APAP elevated the production of oxidative stress and decreased mitochondrial respiratory chain activation in WT mice, which was strongly reversed in CXCL16-knockout mice. In addition, CXCL16 deficiency inhibited the neutrophil infiltration and the production of proinflammatory cytokines triggered by APAP-overdose treatment. Our study revealed that CXCL16 is a critical regulator of liver immune response to APAP-induced hepatotoxicity, thus providing a potential strategy for the treatment of drug-induced acute liver failure by targeting CXCL16.

Investigating the CYP2E1 Potential Role in the Mechanisms Behind INH/LPS-Induced Hepatotoxicity

Tuberculosis (TB) is one of the oldest infectious diseases that affected humankind and remains one of the world's deadliest communicable diseases that could be considered as global emergency, but the discovery and development of isoniazid (INH) in the 1950s paved the way to an effective single and/or combined first-line anti-TB therapy. However, administration of INH induces severe hepatic toxicity in some patients. Previously, we establish a rat model of INH hepatotoxicity utilizing the inflammatory stress theory, in which bacterial lipopolysaccharide (LPS) potentially enhanced INH toxicity. These enhancing activities ranged between augmenting the inflammatory stress, oxidative stress, alteration of bile acid homeostasis, and CYP2E1 over-expression. Although pre-treatment with dexamethasone (DEX) helped overcome both inflammatory and oxidative stress which ended-up in alleviation of LPS augmenting effects, but still minor toxicities were being detected, alongside with CYP2E1 over expression. This finding positively indicated the corner-stone role played by CYP2E1 in the pathogenesis of INH/LPS-induced liver damage. Therefore, we examined whether INH/LPS co-treatment with CYP2E1 inhibitor diallyl sulfide (DAS) and DEX can protect against the INH/LPS-induced hepatotoxicity. Our results showed that pre-administration of both DAS and DEX caused significant reduction in serum TBA, TBil, and gamma-glutamyl transferase levels. Furthermore, the histopathological analysis showed that DAS and DEX could effectively reverse the liver lesions seen following INH/LPS treatment and protect against hepatic steatosis as indicated by absence of lipid accumulation. Pre-treatment with DAS alone could not completely block the CYP2E1 protein expression following INH/LPS treatment, as appeared in the immunoblotting and immunohistochemistry results. This is probably due to the fact that the combined enhancement activities of both INH and LPS on CYP2E1 protein expression levels might resist the blocking probabilities of DAS. In the meantime, addition of DEX to the DAS/INH/LPS combination caused a significant reduction in CYP2E1 protein expression as revealed by the immunoblotting and fading coloration in immunohistochemistry results. Thus, addition of DEX and DAS together caused strong protection against INH/LPS-induced hepatic damage. These findings reveal the potential therapeutic value of combining DAS and DEX with INH in TB management for reducing the potential risk and incidences of hepatotoxicity.

Aging of the Liver: What This Means for Patients with HIV

As the HIV population continues to live longer as a result of antiretroviral therapy, liver-related mortality has become one of the leading causes of non-AIDS related death in this patient population. The liver possesses a remarkable regenerative capacity but undergoes complex biological changes in response to aging and inflammation that result in decreased cellular regeneration and a tipping of the scales towards fibrogenesis. Patients with HIV infection have serological evidence of ongoing inflammation, with elevations in some biomarkers persisting despite adequate virologic control. In addition, HIV-co-infected patients have markers of advanced age on liver biopsy and increased prevalence of fibrosis as compared to an age-matched HCV mono-infected cohort. In this review, we will discuss the biology of aging, age-related changes in the liver, and the relevant mechanisms by which HIV causes inflammation in the context of accelerated aging, fibrosis of the liver, and other viral co-infection.

SHYCD induces APE1/Ref-1 subcellular localization to regulate the p53-apoptosis signaling pathway in the prevention and treatment of acute on chronic liver failure

Background & Aims: San huang yin chi decoction(SHYCD) is derived from the yin chen hao decoction, a well-known and canonical Chinese medicine formula from the “Treatise on Febrile Diseases”. Over the past decade, SHYCD has been used to treat and prevent the liver cirrhosis and liver failure. In the present study, we investigated the effects of SHYCD for acute on chronic liver failure(ACLF) and explored its potential mechanism. an ACLF rat model, which induced by carbon tetrachloride (CCl4) combined with D-galactosamine (D-GalN) and lipopolysaccharide(LPS), was used and confirmed by B-ultrasound analysis. Rats were randomly divided into control group, model group, SHYCD-H group, SHYCD-M group, SHYCD-L group, AGNHW group. Compared with the ACLF model group, High, medium, and low doses of SHYCD reduced ALT, AST, TBIL, NH3, IL-1β, IL-6, and TNFα expression levels in the serum, Shorten PT and INR time,and increased Fbg content in the whole blood, increased survival rate of the rats, improved liver pathological changes. APE1 / Ref-1 was mainly expressed in the nucleus, but the nucleus and cytoplasm were co-expressed after hepatocyte injury. SHYCD significantly downregulated APE1/Ref-1 expression in the cytoplasm. Increased APE1/Ref-1, Bcl-2, reduced p53, caspase-3, Bax, and Cyt-c in the total protein. Base on the results, we conclused that High, medium, and low doses of SHYCD could be applied in prevention and treatment of ACLF, and dose-dependent. The possible mechanism is to promote the APE1 / Ref-1 from the cytoplasm to the nuclear transfer, regulation of p53 apoptosis signal pathway prevention and treatment of ACLF.

Detection of Necroptosis in Ligand-Mediated and Hypoxia-Induced Injury of Hepatocytes Using a Novel Optic Probe-Detecting Receptor-Interacting Protein (RIP)1/RIP3 Binding

Liver injury is often observed in various pathological conditions including posthepatectomy state and cancer chemotherapy. It occurs mainly as a consequence of the combined necrotic and apoptotic types of cell death. In order to study liver/hepatocyte injury by the necrotic type of cell death, we studied signal-regulated necrosis (necroptosis) by developing a new optic probe for detecting receptor-interacting protein kinase 1 (RIP)/RIP3 binding, an essential process for necroptosis induction. In the mouse hepatocyte cell line, TIB-73 cells, TNF-α/cycloheximide (T/C) induced RIP1/3 binding only when caspase activity was suppressed by the caspase-specific inhibitor z-VAD-fmk (zVAD). T/C/zVAD-induced RIP1/3 binding was inhibited by necrostatin-1 (Nec-1), an allosteric inhibitor of RIP1. The reduced cell survival by T/C/zVAD was improved by Nec-1. These facts indicate that T/C induces necroptosis of hepatocytes when the apoptotic pathway is inhibited/unavailable. FasL also induced cell death, which was only partially inhibited by zVAD, indicating the possible involvement of necroptosis rather than apoptosis. FasL activated caspase 3 and, similarly, induced RIP1/3 binding when the caspases were inactivated. Interestingly, FasL-induced RIP1/3 binding was significantly suppressed by the antioxidants Trolox and N-acetyl cysteine (NAC), suggesting the involvement of reactive oxygen species (ROS) in FasL-induced necroptotic cellular processes. H₂O₂, by itself, induced RIP1/3 binding that was suppressed by Nec-1, but not by zVAD. Hypoxia induced RIP1/3 binding after reoxygenation, which was suppressed by Nec-1 or by the antioxidants. Cell death induced by hypoxia/reoxygenation (H/R) was also improved by Nec-1. Similar to H₂O₂, H/R did not require caspase inhibition for RIP1/3 binding, suggesting the involvement of a caspase-independent mechanism for non-ligand-induced and/or redox-mediated necroptosis. These data indicate that ROS can induce necroptosis and mediate the FasL- and hypoxia-induced necroptosis via a molecular mechanism that differs from a conventional caspase-dependent pathway. In conclusion, necroptosis is potentially involved in liver/hepatocyte injury induced by oxidative stress and FasL in the absence of apoptosis.

Inhibitory effect of oxymatrine on hepatocyte apoptosis via TLR4/PI3K/Akt/GSK-3β signaling pathway

AIM

To evaluate the effect of oxymatrine (OMT) on hepatocyte apoptosis in rats with lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver failure (ALF).

METHODS

LPS/D-GalN was used to establish a model of ALF in rats. To evaluate the effect of OMT, we assessed apoptosis by transmission electron microscopy, and the pathological changes in the liver by light microscopy with hematoxylin and eosin staining. An automated biochemical analyzer was used to measure serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Enzyme-linked immunosorbent assay was used to determine the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β. Western blotting was used to detect protein levels in liver tissues. Streptavidin peroxidase immunohistochemistry was used to observe expression of Toll-like receptor (TLR)4, active caspase-3, Bax and Bcl-2.

RESULTS

All rats in the normal control and OMT-pretreated groups survived. The mortality rate in the model group was 30%. OMT preconditioning down-regulated apoptosis of hepatocytes and ameliorated pathological changes in liver tissue. The levels of AST, ALT, TNF-α and IL-1β in the model group increased significantly, and were significantly reduced by OMT pretreatment. OMT pretreatment down-regulated expression of TLR4 and active caspase-3 and the Bax/Bcl-2 ratio, and up-regulated expression of P-Akt^Ser473 (Akt phosphorylated at serine 473) and P-GSK3β^Ser9 (glycogen synthase kinase 3β phosphorylated at serine 9) induced by LPS/D-GalN.

CONCLUSION

OMT inhibits hepatocyte apoptosis by suppressing the TLR4/PI3K/Akt/GSK-3β signaling pathway, which suggests that OMT is an effective candidate for ameliorating acute liver failure.

Combination of tauroursodeoxycholic acid and N-acetylcysteine exceeds standard treatment for acetaminophen intoxication

BACKGROUND & AIMS

Acetaminophen overdose in mice is characterized by hepatocyte endoplasmic reticulum stress, which activates the unfolded protein response, and centrilobular hepatocyte death. We aimed at investigating the therapeutic potential of tauroursodeoxycholic acid, a hydrophilic bile acid known to have anti-apoptotic and endoplasmic reticulum stress-reducing capacities, in experimental acute liver injury induced by acetaminophen overdose.

METHODS

Mice were injected with 300 mg/kg acetaminophen, 2 hours prior to receiving tauroursodeoxycholic acid, N-acetylcysteine or a combination therapy, and were euthanized 24 hours later. Liver damage was assessed by serum transaminases, liver histology, terminal deoxynucleotidyl transferase dUTP nick end labelling staining, expression profiling of inflammatory, oxidative stress, unfolded protein response, apoptotic and pyroptotic markers.

RESULTS

Acetaminophen overdose resulted in a significant increase in serum transaminases, hepatocyte cell death, unfolded protein response activation, oxidative stress, NLRP3 inflammasome activation, caspase 1 and pro-inflammatory cytokine expressions. Standard of care, N-acetylcysteine and, to a lesser extent, tauroursodeoxycholic treatment were associated with significantly lower transaminase levels, hepatocyte death, unfolded protein response activation, oxidative stress markers, caspase 1 expression and NLRP3 levels. Importantly, the combination of N-acetylcysteine and tauroursodeoxycholic acid improved serum transaminase levels, reduced histopathological liver damage, UPR-activated CHOP, oxidative stress, caspase 1 expression, NLRP3 levels, IL-1β levels and the expression of pro-inflammatory cytokines and this to a greater extend than N-acetylcysteine alone.

CONCLUSIONS

These findings indicate that a combination strategy of N-acetylcysteine and tauroursodeoxycholic acid surpasses the standard of care in acetaminophen-induced liver injury in mice and might represent an attractive therapeutic opportunity for acetaminophen-intoxicated patients.

Usefulness of in vitro combination assays of mitochondrial dysfunction and apoptosis for the estimation of potential risk of idiosyncratic drug induced liver injury

Drug-induced liver injury (DILI) is one of the serious and frequent drug-related adverse events. This adverse event is a main reason for regulatory action pertaining to drugs, including restrictions in clinical indications and withdrawal from clinical trials or the marketplace. Idiosyncratic DILI especially has become a major clinical concern because of its unpredictable nature, frequent hospitalization, need for liver transplantation and high mortality. The estimation of the potential for compounds to induce idiosyncratic DILI is very difficult in non-clinical studies because the precise mechanism of idiosyncratic DILI is still unknown. Recently, many in vitro assays which indicate a possibility of the prediction of the idiosyncratic DILI have been reported. Among these, some in vitro assays focus on the effects of compounds on mitochondrial function and the apoptotic effects of compounds on human hepatocytes. In this study, we measured oxygen consumption rate (OCR) and caspase-3/7 activity as an endpoint of mitochondrial dysfunction and apoptosis, respectively, with human hepatocytes after treatment with compounds causing idiosyncratic DILI (troglitazone, leflunomide, ranitidine and diclofenac). Troglitazone and leflunomide decreased the OCR but did not affect caspase-3/7 activity. Ranitidine increased caspase-3/7 activity but did not affect the OCR. Diclofenac decreased the OCR and increased caspase-3/7 activity. Acetaminophen and ethanol, which are also hepatotoxicants but do not induce idiosyncratic DILI, did not affect the OCR or caspase-3/7 activity. These results indicate that a combination assay of mitochondrial dysfunction and apoptosis is useful for the estimation of potential risk of compounds to induce idiosyncratic DILI.

Icariin-treated human umbilical cord mesenchymal stem cells decrease chronic liver injury in mice

Human umbilical cord mesenchymal stem cells (hUMSCs) have been shown to have multiple differentiation potentials. However, a key problem is that only a small number of hUMSCs can migrate to damaged tissue after transplantation. According to "The Theory of Kidney Essence" in Traditional Chinese Medicine, some traditional Chinese medicines used for tonifying the kidneys can be applied in promoting the differentiation and migration of stem cells in vivo. Our previous study demonstrated that icariin (ICA) could up-regulate the pluripotent genes of hUMSCs in vitro and induce cell migration in mice in an acute kidney injury model in vivo. The aim of this study was to investigate the effects of ICA-induced hUMSCs in chronic liver injury (CLI) caused by carbon tetrachloride (CCl4). CLI was induced by intraperitoneal injection of CCl4. ICA-treated hUMSCs were transplanted via intra-venous injection. The animals were followed for survival, biochemistry analysis and pathology. The results show that ICA-treated hUMSCs accelerate the recovery of liver function in mice with CLI. In addition, ICA-treated hUMSCs increase the anti-oxidant activities in liver and prevent the progression to hepatic fibrosis. Moreover, ICA induces the migration of hUMSCs to the injured liver tissue. In conclusion, these data demonstrate that ICA-treated hUMSCs exhibit recovery and protective properties in the mice model of CCl4-induced CLI.

Necroptosis in amyotrophic lateral sclerosis and other neurological disorders

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive degeneration of upper and lower motor neurons. Cell death in ALS and in general was previously believed to exist as a dichotomy between apoptosis and necrosis. Most research investigating cell death mechanisms in ALS was conducted before the discovery of programmed necrosis thus did not use selective cell death pathway-specific markers. Recently, a new form of programmed cell death, termed "necroptosis", has been characterized and has been recently implicated in ALS as a primary mechanism driving motor neuron cell death in different forms of ALS. The present review is aimed at summarizing cell death pathways that are currently implicated in ALS and highlighting the emerging evidence on necroptosis as a major driver of motor neuron cell death.

Infiltrating monocytes in liver injury and repair

Noninfectious liver injury causes many acute and chronic liver diseases around the globe, and particularly in developed nations. Bone marrow-derived monocytes infiltrate the damaged liver tissue and are a critical component of the innate immune response that may drive injury resolution or host death in the short term or chronic inflammation, fibrosis and hepatocellular carcinoma in the long term. Monocytes often play dual roles in liver injury—both perpetuating inflammation and promoting resolution of inflammation and fibrosis. Thus, we will address the role that monocytes play in different experimental forms of noninfectious liver injury; considering in particular the importance of the transition from inflammatory Ly6C^hi monocytes to pro-resolution Ly6C^lo monocyte-derived macrophages and the consequences of this transition for disease progression and resolution.

Proteomic analysis of acetaminophen-induced hepatotoxicity and identification of heme oxygenase 1 as a potential plasma biomarker of liver injury

PURPOSE

Overdose of acetaminophen (APAP) is a major cause of acute liver failure. This study was aimed to identify pathways related to hepatotoxicity and potential biomarkers of liver injury.

EXPERIMENTAL DESIGN

Rats were treated with low (100 mg/kg) and high (1250 mg/kg) doses of APAP, and liver tissues at 6 and 24 h post-treatment were analyzed using a proteomic approach of 16O/18O labeling and 2D-LC-MS/MS.

RESULTS

Molecular pathways evolved progressively from scattered and less significant perturbations to more focused and significant alterations in a dose- and time-dependent manner upon APAP treatment. Imbalanced expression of hemeoxygenase 1 (HMOX1) and biliverdin reductase A (BLVRA) was associated with hepatotoxicity. Protein abundance changes of a total of 31 proteins were uniquely correlated to liver damage, among which a dramatic increase of HMOX1 levels in plasma was observed. Liver injury-associated significant elevation of plasma HMOX1 was further validated in mice treated with APAP.

CONCLUSIONS AND CLINICAL RELEVANCE

This study unveiled molecular changes associated with APAP-induced liver toxicity at the pathway levels and identified HMOX1 as a potential plasma biomarker of liver injury.

Hepatoprotective effects of Flagellaria indica are mediated through the suppression of pro-inflammatory cytokines and oxidative stress markers in rats

Context The antioxidative properties of plants or plant derivative products are well known for their free radical scavenging effects. Flagellaria indica L. (Flagellariaceae) (FI) is a tropical medicinal plant used by the natives of Sabah as medication for semi-paralysis. Objective This study evaluates the hepatoprotective mechanism of FI against carbon tetrachloride (CCl4)-mediated liver damage. Materials and methods Aqueous extract of FI leaves was orally administered to adult Sprague-Dawley rats once daily for 14 consecutive days at 300, 400, and 500 mg/kg b.w. prior to CCl4 treatment (1.0 mL/kg b.w.) on the 13th and 14th days. Results Total phenolic content in the aqueous extract of FI leaves was 65.88 ± 1.84 mg gallic acid equivalent/g. IC50 value for free radical scavenging activity of FI aqueous extract was reached at the concentration of 400 μg/mL. Biochemical studies show that the aqueous extract of FI was able to prevent the increase in levels of serum transaminases, alanine aminotransferase, and aspartate aminotransferase (38-74% recovery), and malondialdehyde formation (25-87% recovery) in a dose-dependent manner. Immunohistochemical results evidenced the suppression of oxidative stress markers (4-hydroxynonenal and 8-hydroxydeoxyguanosine) and pro-inflammatory markers (tumour necrosis factor-α, interleukin-6, prostaglandin E2). Histopathological and hepatocyte ultrastructural alterations proved that there were protective effects in FI against CCl4-mediated liver injury. Signs of toxicity were not present in rats treated with FI alone (500 mg/kg b.w.). Discussion and conclusion It can be concluded that the presence of phenolic constituents and their antioxidative effects can be credited to the hepatoprotective activity of FI.

Activation of the JNK-c-Jun pathway in response to irradiation facilitates Fas ligand secretion in hepatoma cells and increases hepatocyte injury

Background

It is well established that some irradiated liver non-parenchymal cells secrete pro-inflammatory cytokines to facilitate the development of radiation-induced liver disease. However, little is known on whether the irradiated hepatoma cells-mediated non-irradiated hepatocyte injury occurs in HCC patients. Here, we elucidated the roles of the irradiated hepatoma cells in driving non-irradiated hepatocyte injury and its underlying mechanism.

Methods

SMMC7721 cells were cultured and divided into irradiated (4-Gy X-ray, R) and non-irradiated (NR) groups. At 24th hour after irradiation, conditioned medium (CM) from these cultures was mixed with normal culture medium in specific proportions, and termed as 7721-R-CM and 7721-NR-CM. Following incubation with these CM compound, the biological characteristics of L02 cells related to liver cell injury including viability, apoptosis and liver dysfunction indices were comparatively analyzed. Simultaneously, the levels of proliferation- and apoptosis-related cytokines in irradiated and non-irradiated SMMC7721 cells were also measured. FasL as a cytokine with significantly differential expression, was selected to clarify its effects on L02 apoptosis. Subsequently, FasL expression following irradiation was examined in SMMC7721 and other HCC cells with varying malignant potentials, as well as in HCC tissues, the related mechanism of higher expression of FasL in irradiated HCC cells was further investigated.

Results

Apoptosis and liver dysfunction indices were all significantly enhanced in L02 cells treated with 7721-R-CM, whereas viability was suppressed, compared to those with 7721-NR-CM stimulation. FasL was identified as a leading differential cytokine in the irradiated SMMC7721 cells. Higher proportion of apoptosis was also found in L02 cells following FasL incubation. A recombinant Fas-Fc protein, which blocks Fas-FasL interaction, ameliorated 7721-R-CM-induced apoptosis in L02 cells. FasL was highly expressed in a dose-dependent manner, and peaked at the 24th hour post-irradiation in different HCC cells and their culture supernatant. Meanwhile, phosphorylation levels of JNK, ERK, Akt, and p38 were all upregulated significantly in irradiated HCC cells. But, only JNK inhibition was validated to block radiation-induced FasL expression in HCC cells. c-Jun, the target transcription factor of JNK, was also activated.

Conclusion

In HCC cells, the JNK-c-Jun pathway plays an important role in mediating irradiation- induced FasL expression, which may be critical in determining non-irradiated hepatocyte injury.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0394-z) contains supplementary material, which is available to authorized users.

Roles of oxidative stress, apoptosis, and heme oxygenase-1 in ethylbenzene-induced renal toxicity in NRK-52E cells

Ethylbenzene is an important industrial chemical, but its potential toxicity is a recent concern. Our previous study investigated the renal toxicity of ethylbenzene in vivo. Rat renal epithelial cells (NRK-52E cells) were incubated with 0, 30, 60, and 90 µmol/L of ethylbenzene for 24 h in vitro to investigate ethylbenzene-induced oxidative stress, apoptosis, and the expression of heme oxygenase 1 (HO-1) and nuclear factor (erythroid 2)-related factor 2 (Nrf2). The cell survival rate in the ethylbenzene-treated groups was significantly lower than the control group. Ethylbenzene significantly increased intracellular reactive oxygen species and apoptosis. Malondialdehyde levels were significantly elevated compared with the control group, while glutathione levels and glutathione peroxidase activities were decreased in ethylbenzene-treated groups. The activities of catalase and superoxide dismutase were also markedly reduced. A significant dose-dependent increase in HO-1 and Nrf2 messenger RNA expression levels was observed in ethylbenzene-treated groups compared with the control group. Similarly, ethylbenzene treatment enhanced protein expression of HO-1 and Nrf2 in a dose-dependent manner. Our results indicated that ethylbenzene induced oxidative stress, apoptosis, and upregulation of HO-1 and Nrf2 in NRK-52E cells, which contributes to ethylbenzene-induced renal toxicity.

Effect of Yinchenhao decoction on expression of IRE1α protein in liver cells of rats with obstructive jaundice

AIM: To investigate the effect of medicated serum of Yinchenhao decoction on inositol-requiring enzyme-1-α (IRE1α) protein expression in hepatocytes of rats with obstructive jaundice.

METHODS: Common bile duct ligation was used to generate an SD rat model of obstructive jaundice. Primary hepatocytes were isolated from the rat models. Gavage administration with Yinchenhao decoction was applied to prepare serum containing the corresponding drug. Yinchenhao decoction serum was added into the medium for primary hepatocyte culture in the administrated group (Group B), while the medium containing no drug was used in the sham group (Group A). The expression of IRE1αprotein in cells as well as alanine transaminase (ALT) and aspartate transaminase (AST) in culture fluid was detected.

RESULTS: The levels of IRE1α expression, AST and ALT in group B were significantly lower than those in group A at all time points (expression of IRE1α: 6 h 1.85 ± 0.04 vs 1.58 ± 0.04, 24 h 1.95 ± 0.02 vs 1.60 ± 0.03, 48 h 2.22 ± 0.13 vs 1.99 ± 0.10, P < 0.05; AST: 6 h 17.23 U/L ± 3.01 U/L vs 13.13 U/L ± 2.41 U/L, 24 h 19.33 U/L ± 3.01 U/L vs 15.67 U/L ± 2.36 U/L, 48 h 24.40 U/L ± 3.93 U/L vs 19.18 U/L ± 1.65 U/L, P < 0.05; ALT: 6 h 17.23 U/L ± 3.01 U/L vs 13.13 U/L ± 2.41 U/L, 24 h 19.33 U/L ± 3.01 U/L vs 15.67 U/L ± 2.36 U/L, 48 h 24.40 U/L ± 3.93 U/L vs 19.18 U/L ± 1.65 U/L, P < 0.05).

CONCLUSION: Serum pharmacology test can be used for pharmacodynamic evaluation of Yinchenhao decoction. The endoplasmic reticulum stress mediated by IRE1α might be an important pathway by which Yinchenhao decoction exerts a protective effect on hepatocytes of rats with obstructive jaundice.

ER stress contributes to alpha-naphthyl isothiocyanate-induced liver injury with cholestasis in mice

Endoplasmic reticulum (ER) stress is involved in the development of several liver diseases and tumors. This study investigated the underlying mechanisms of α-naphthyl isothiocyanate (ANIT)-induced liver injury with cholestasis in mice and found ER stress contributes to the injury. All animals were randomly divided into three groups. In the ANIT-intoxicated group, mice were intragastrically given 100mg/kg ANIT (dissolved in corn oil), while the other groups received an equal volume of vehicle as control. After 24 and 48h of ANIT administration, blood samples and liver tissues of all animals were collected for serum biochemistry and hepatic histopathological examinations to evaluate liver injuries with cholestasis. Hepatocellular apoptosis was assessed by the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. The expression of hepatic ER stress-related markers was determined by real-time PCR, immunohistochemical assay and Western blot. ANIT was found to significantly induce liver injury with cholestasis compared with control mice as evidenced by the increase of serum transaminases and total bilirubin (TBil), and histopathological changes in mice. ANIT remarkably induced hepatocellular apoptosis, upregulated the expression of caspase-9 and cytochrome c, and inhibited the gene and protein expression of proliferating cell nuclear antigen (PCNA). The gene expression of ER stress-related markers, including glucose-regulated protein 78 (GRP78), protein kinase R-like ER kinase (PERK), eukaryotic initiation factor 2α (eIF2α), inositol requiring enzyme-1α (IRE-1α) and activating transcription factor 6 (ATF6) was upregulated by ANIT in mice. ANIT also upregulated the protein expression of GRP78 and activated the phosphorylation of IRE1. These results suggested that ANIT induced liver injury with cholestasis partly due to its ability to activate the ER stress pathway.