Suppressed Hepatocyte Apoptosis Research Articles

Protective Effect of Ginsenoside CK against Autoimmune Hepatitis Induced by Concanavalin A.

Ginsenoside CK, a kind of rare ginsenoside transformed from protopanaxadiol saponins extracted from the genus Panax, has been proven to possess favorable bioactivities such as anti-inflammatory, anti-cancer, anti-diabetes, and hepatoprotective effects. The current study is targeted to determine the effect of ginsenoside CK on hepatitis induced by concanavalin A (Con A). Mice were treated with different dosages of ginsenoside CK for 7 days, and Con A (15 mg/kg) was intravenously injected to induce autoimmune hepatitis (AIH) after the last administration. The results demonstrated that pretreatment with ginsenoside CK (40 mg/kg) could obviously ameliorate the increase in serum indicators related to liver function such as AST, ALT, and ALP, and hepatic lesions induced by Con A. Meanwhile, ginsenoside CK suppressed hepatocyte apoptosis, which was observed in pathological data, and immunoblotting results showed that the expression of Bax, Bcl-2, and other proteins was regulated by CK. Furthermore, the release of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and IL-6 in mice with AIH were lowered by the administration of 40 mg/kg of ginsenoside CK. Furthermore, ginsenoside CK elevated the gene expression of Nrf2 and Sirt1 and augmented downstream target genes such as HO-1. In addition, a significant inhibition effect of the TLR4/NF-κB signal was observed in 40 mg/kg CK-pretreated mice compared with the model group. To sum up, the results indicated that ginsenoside CK has a notable hepatoprotective effect against AIH by activating Sirt1/Nrf2 and suppressing the TLR4/NF-κB signaling pathway.

Silencing of GDF11 suppresses hepatocyte apoptosis to relieve LPS/D-GalN acute liver failure.

In this paper, we generated a short hairpin RNA growth differentiation factor-11 (sh-GDF11) and evaluated the effects of sh-GDF11 on the pathogenesis of acute liver failure (ALF) in vitro and in vivo. Through bioinformatics study, the key gene related to ALF was assayed. Lipopolysaccharide (LPS) and D-galactoamine (D-GalN) were applied to establish the mouse model of LPS/D-GalN-induced liver injury, and TNF-α and D-Gal were used to construct an in vitro cell model, followed by treatment of sh-GDF11 for analysis of liver cell proliferation. Bioinformatics analysis showed that the protective effect of sh-GDF11 on ALF may be mediated by phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway. The results of in vitro study found that sh-GDF11 could promote cell proliferation and inhibit death by blocking the PI3K/Akt/mTOR signaling pathway. In vivo animal experiments further confirmed that sh-GDF11 could suppress hepatocyte apoptosis by inhibiting the PI3K/Akt/mTOR signaling pathway. sh-GDF11 relieved LPS/D-GalN-induced ALF by blocking the PI3K/Akt/mTOR signaling pathway, emphasizing its critical role in LPS/D-GalN-induced ALF treatment.

Extract of Triticum aestivum Sprouts Suppresses Acetaminophen-Induced Hepatotoxicity in Mice by Inhibiting Oxidative Stress.

Wheat (Triticum aestivum L.) is the oldest known food crop, and many studies have reported that wheat shoots (i.e., wheatgrass) possess anti-cancer, anti-inflammatory, and antioxidant activities. However, the potentially ameliorative effect of wheat shoots on hepatotoxicity caused by high doses of N-acetyl-para-aminophenol (acetaminophen, APAP) has yet to be reported. C57BL/6 mice received daily oral TAE (100 or 200 mg/kg), positive control (silymarin 100 mg/kg), or negative control (saline vehicle) treatments for 7 days prior to intraperitoneal APAP injection. Histological, serum (ELISA), Western blotting, and quantitative PCR analyses of excised liver tissues were then performed. Pre-treatment with TAE (100 or 200 mg/kg) ameliorated APAP-induced pathological damage (i.e., hepatotoxic lesions), reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and also ameliorated APAP-induced increases in oxidative stress, thereby inhibiting oxidative liver damage and reducing the expression of inflammatory cytokines. In addition, TAE pre-treatment inhibited the expression of Cytochrome P4502E1 (CYP2E1), which is a key enzyme in the onset of APAP-induced hepatotoxicity, suppressed the expression of the target proteins regulated by the antioxidant enzyme Nrf2, and suppressed hepatocyte apoptosis. These findings suggest that TAE is an attractive therapeutic candidate that exhibits potential hepatoprotective activity by inhibiting oxidative stress, inflammation, apoptosis, and liver damage.

Prussian Blue Nanozymes Prevent Anthracycline-Induced Liver Injury by Attenuating Oxidative Stress and Regulating Inflammation.

Anthracycline-induced liver injury (AILI) is becoming an increasingly serious and potential clinical complication and is linked to reactive oxygen species (ROS) production and subsequent inflammatory response. Herein, we demonstrated that artificial Prussian blue nanozymes (PBZs) prevented daunorubicin-induced liver injury, a prototype of AILI, by attenuating ROS production and regulating inflammation. PBZs exhibited multienzyme activity and could scavenge ROS and free radicals. At the cellular level, PBZs could effectively eliminate ROS, suppress hepatocyte apoptosis, reduce deoxyribonucleic acid damage, and decrease the levels of inflammatory cytokines and chemokines. According to the results of the in vivo study, pretreatment with PBZs also resulted in a desirable protective effect against AILI, as indicated by both a decrease in biochemical indicator levels and hepatocyte necrosis. PBZs upregulated antioxidative genes by activating the Nrf2 pathway to reduce oxidative stress. Meanwhile, PBZs counteracted the inflammatory response based on the decreased expression levels of myeloperoxidase and F4/80 in the liver. Collectively, our findings indicate that PBZ-based nanotherapy is a novel strategy for protecting against AILI.

Oleoylethanolamide Protects Against Acute Liver Injury by Regulating Nrf-2/HO-1 and NLRP3 Pathways in Mice.

Acute liver injury is a rapidly deteriorating clinical condition with markedly high morbidity and mortality. Oleoylethanolamide (OEA) is an endogenous lipid messenger with multiple bioactivities, and has therapeutic effects on various liver diseases. However, effects of OEA on acute liver injury remains unknown. In this study, effects and mechanisms of OEA in lipopolysaccharide (LPS)/d-galactosamine (D-Gal)-induced acute liver injury in mice were investigated. We found that OEA treatment significantly attenuated LPS/D-Gal-induced hepatocytes damage, reduced liver index (liver weight/body weight), decreased plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels. Moreover, mechanism study suggested that OEA pretreatment significantly reduced hepatic MDA levels, increased Superoxide dismutase (SOD) and Glutathione peroxidase (GSH-PX) activities via up-regulate Nrf-2 and HO-1 expression to exert anti-oxidation activity. Additionally, OEA markedly reduced the expression levels of Bax, Bcl-2 and cleaved caspase-3 to suppress hepatocyte apoptosis. Meanwhile, OEA remarkedly reduced the number of activated intrahepatic macrophages, and alleviated the mRNA expression of pro-inflammatory factors, including TNF-α, IL-6, MCP1 and RANTES. Furthermore, OEA obviously reduced the expression of IL-1β in liver and plasma through inhibit protein levels of NLRP3 and caspase-1, which indicated that OEA could suppress NLRP3 inflammasome pathway. We further determined the protein expression of PPAR-α in liver and found that OEA significantly increase hepatic PPAR-α expression. In addition, HO-1 inhibitor ZnPP blocked the therapeutic effects of OEA on LPS/D-Gal-induced liver damage and oxidative stress, suggesting crucial role of Nrf-2/HO-1 pathway in the protective effects of OEA in acute liver injury. Together, these findings demonstrated that OEA protect against the LPS/D-Gal-induced acute liver injury in mice through the inhibition of apoptosis, oxidative stress and inflammation, and its mechanisms might be associated with the Nrf-2/HO-1 and NLRP3 inflammasome signaling pathways.

REV-ERBα Agonist GSK4112 attenuates Fas-induced Acute Hepatic Damage in Mice.

Fas-induced apoptosis is a central mechanism of hepatocyte damage during acute and chronic hepatic disorders. Increasing evidence suggests that circadian clock plays critical roles in the regulation of cell fates. In the present study, the potential significance of REV-ERBα, a core ingredient of circadian clock, in Fas-induced acute liver injury has been investigated. The anti-Fas antibody Jo2 was injected intraperitoneally in mice to induce acute liver injury and the REV-ERBα agonist GSK4112 was administered. The results indicated that treatment of GSK4112 decreased the level of plasma ALT and AST, attenuated the liver histological changes, and promoted the survival rate in Jo2-insulted mice. Treatment with GSK4112 also downregulated the activities of caspase-3 and caspase-8, suppressed hepatocyte apoptosis. In addition, treatment with GSK4112 decreased the level of Fas and enhanced the phosphorylation of Akt. In conclusion, treatment with GSK4112 alleviated Fas-induced apoptotic liver damage in mice, suggesting that REV-ERBα agonist might have potential value in pharmacological intervention of Fas-associated liver injury.

Mild Hypothermia Attenuates Hepatic Ischemia-Reperfusion Injury through Regulating the JAK2/STAT3-CPT1a-Dependent Fatty Acid β-Oxidation.

Hepatic ischemia–reperfusion (IR) injury is a clinical issue that can result in poor outcome and lacks effective therapies at present. Mild hypothermia (32–35°C) is a physiotherapy that has been reported to significantly alleviate IR injury, while its protective effects are attributed to multiple mechanisms, one of which may be the regulation of fatty acid β-oxidation (FAO). The aim of the present study was to investigate the role and underlying mechanisms of FAO in the protective effects of mild hypothermia. We used male mice to establish the experimental models as previously described. In brief, before exposure to in situ ischemia for 1 h and reperfusion for 6 h, mice received pretreatment with mild hypothermia for 2 h and etomoxir (inhibitor of FAO) or leptin (activator of FAO) for 1 h, respectively. Then, tissue and blood samples were collected to evaluate the liver injury, oxidative stress, and changes in hepatic FAO. We found that mild hypothermia significantly reduced the hepatic enzyme levels and the score of hepatic pathological injury, hepatocyte apoptosis, oxidative stress, and mitochondrial injury. In addition, the expression of the rate-limiting enzyme (CPT1a) of hepatic FAO was downregulated almost twofold by IR, while this inhibition could be significantly reversed by mild hypothermia. Experiments with leptin and etomoxir confirmed that activation of FAO could also reduce the hepatic enzyme levels and the score of hepatic pathological injury, hepatocyte apoptosis, oxidative stress, and mitochondrial injury induced by IR, which had the similar effects to mild hypothermia, while inhibition of FAO had negative effects. Furthermore, mild hypothermia and leptin could promote the phosphorylation of JAK2/STAT3 and upregulate the ratio of BCL-2/BAX to suppress hepatocyte apoptosis. Thus, we concluded that FAO played an important role in hepatic IR injury and mild hypothermia attenuated hepatic IR injury mainly via the regulation of JAK2/STAT3-CPT1a-dependent FAO.

Succinate dehydrogenase inhibitor dimethyl malonate alleviates LPS/d-galactosamine-induced acute hepatic damage in mice.

In addition to its energy-supplying function, increasing evidence suggests that mitochondria also play crucial roles in the regulation of inflammation. Succinate dehydrogenase is also known as mitochondrial complex II, and inhibition of succinate dehydrogenase by dimethyl malonate has been reported to suppress the production of pro-inflammatory cytokines. In the present study, the potential anti-inflammatory benefits of dimethyl malonate were investigated in a mouse model with LPS/d-galactosamine-induced acute hepatic damage. Male BALB/c mice were injected i.p. with LPS and d-galactosamine to cause liver injury. The degree of liver injury, inflammatory response and oxidative stress and the survival of the experimental animals were determined. The results indicated dimethyl malonate decreased the level of aminotransferases in plasma, alleviated histological abnormalities in liver, inhibited the induction of TNF-α and IL-6 in plasma, suppressed hepatocyte apoptosis and improved the survival of LPS/d-galactosamine-exposed mice. Therefore, inhibition of succinate dehydrogenase by dimethyl malonate significantly alleviated LPS/d-galactosamine-induced hepatic damage, which suggests that succinate dehydrogenase might become a novel target for the intervention of inflammation-based hepatic disorders.

FLT3/FLT3L-mediated CD103+ dendritic cells alleviates hepatic ischemia-reperfusion injury in mice via activation of treg cells

BackgroundThis study was conducted to investigate the protective effect of Fms-like tyrosine kinase 3 (FLT3)/FLT3 ligand (FLT3L)-dependent CD103+ dendritic cells (DCs) on hepatic ischemia-reperfusion injury (IRI). MethodsA mouse model of hepatic IRI and cellular model following hypoxia-reperfusion (H/R) treatment were established. Peripheral blood and liver tissues were obtained and analyzed by flow cytometer in terms of percentage of CD103+DCs and regulatory T (Treg) cells. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were determined to assess liver function. Moreover, pro-inflammatory cytokines levels including tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were measured using enzyme-linked immunosorbent assay (ELISA). The histological morphology of liver tissues was examined with hematoxylin and eosin (HE) staining. The apoptosis was detected by terminal deoxynucleotidyl transferase (TdT) dUTP Nick End Labeling (TUNEL) assay. Treg-associated cytokines transforming growth factor (TGF)-β and IL-10 expressions were measured using quantitative real time polymerase chain reaction (qRT-PCR). ResultsCD103+ DCs were significantly decreased in peripheral blood and liver tissues of mouse model of hepatic IRI. In vivo experiments indicated that CD103+ DCs infusion ameliorated IRI-induced liver damage and Treg inhibition. Further investigations demonstrated that FLT3/FLT3L-dependent CD103+ DCs suppressed hepatocyte apoptosis via activation of Treg cells in vitro. ConclusionFLT3/FLT3L-induced CD103+ DCs alleviated hepatic IRI through activating Treg cells.

LINC01093 Upregulation Protects against Alcoholic Hepatitis through Inhibition of NF-κB Signaling Pathway

The long noncoding RNAs (lncRNAs) have been proven to be involved in the development of alcoholic hepatitis (AH), which has been regarded as a severe form of acute liver injury with a high mortality rate. Through the GEO database, the differentially expressed LINC01093 and intercellular cell adhesion molecule-1 (ICAM-1) were identified in AH. Then, to clarify their specific role and underlying mechanism in AH, we constructed an AH mouse model by using Lieber-Decarli alcoholic feed. It was found that LINC01093 was poorly expressed and ICAM-1 was highly expressed in AH mice. After that, the interactions among LINC01093, ICAM-1, and NF-κB signaling pathway were explored, which verified that LINC01093 could target ICAM-1 and inhibit the NF-κB signaling pathway. Finally, after the hepatocytes were isolated from AH mice, the expression of LINC01093 was up- or downregulated or that of ICAM-1 was silenced to evaluate their effect on cell viability and apoptosis. The corresponding results demonstrated that after overexpression of LINC01093 or silencing of ICAM-1, cell viability was increased and cell apoptosis was reduced in the hepatocytes of AH mice. Moreover, the silencing of LINC01093 was observed to inhibit the viability and promote the apoptosis of hepatocytes of AH mice. Altogether, these results provide evidence that overexpression of LINC01093 could effectively suppress hepatocyte apoptosis and promote proliferation by inhibiting the ICAM-1-mediated NF-κB signaling pathway, thus playing a functional role in AH and hepatic fibrosis.

Phosphodiesterase III inhibitor attenuates rat sinusoidal obstruction syndrome through inhibition of platelet aggregation in Disse's space.

Sinusoidal obstruction syndrome (SOS) is a serious drug-induced liver injury. However, the pathophysiology of the disease remains unclear. This study investigated the effects of cilostazol (CZ), a phosphodiesterase III inhibitor, in a monocrotaline (MCT)-induced rat model of SOS. Male Wistar rats were administrated MCT to induce SOS. Rats were divided into control, MCT, and MCT+CZ groups. In the MCT+CZ group, CZ was administered at 48h, 24h, and 30min prior to and 8h and 24h after MCT administration. The MCT group was treated with water instead of CZ. At 48h after MCT administration, blood and liver samples were collected to assess biochemistry and liver histology. Expression of rat endothelial cell antigen, CD34, CD41, P-selectin, and caspase-3 in the liver were analyzed. Plasminogen activator inhibitor-1 (PAI-1) in hepatocytes was analyzed using western blotting and polymerase chain reaction. In the MCT group, macroscopic findings showed a dark-red liver surface. Histological findings showed sinusoidal dilatation, coagulative necrosis of hepatocytes, and endothelial damage of the central vein. These changes were attenuated in the MCT+CZ group. Elevated serum transaminase and decreased platelet counts were observed in the MCT+CZ group compared with those in the MCT group. Treatment with CZ reduced MCT-induced damage to the liver sinusoidal endothelial cells, inhibited extravasated platelet aggregation, and suppressed hepatocyte apoptosis around the central vein. CZ attenuated hepatic PAI-1 protein and mRNA levels. Cilostazol attenuated MCT-induced SOS by preventing damage to liver sinusoidal endothelial cells and extravasated platelet aggregation. Hepatic PAI-1 levels were suppressed with CZ treatment.

Secreted Ectodomain of SIGLEC-9 and MCP-1 Synergistically Improve Acute Liver Failure in Rats by Altering Macrophage Polarity

Effective treatments for acute liver failure (ALF) are still lacking. We recently reported that a single intravenous administration of serum-free conditioned medium from stem cells derived from human exfoliated deciduous teeth (SHED-CM) into the D-galactosamine (D-Gal)-induced rat ALF model improves the liver injury. However, the specific factors in SHED-CM that are responsible for resolving ALF remain unclear. Here we found that depleting SHED-CM of two anti-inflammatory M2 macrophage inducers—monocyte chemoattractant protein-1 (MCP-1) and the secreted ectodomain of sialic acid-binding Ig-like lectin-9 (sSiglec-9)—abolished its ability to resolve rat ALF. Furthermore, treatment with MCP-1/sSiglec-9 alone dramatically improved the survival of ALF rats. This treatment induced anti-inflammatory M2, suppressed hepatocyte apoptosis, and promoted hepatocyte proliferation. Treatment with an M2-depletion reagent (mannosylated clodronate liposomes) suppressed the recovery. In addition, MCP-1 and sSiglec-9 synergistically promoted the M2 differentiation of bone marrow-derived macrophages via CCR2, accompanied by the production of multiple liver-regenerating factors. The conditioned medium from MCP-1/sSiglec-9-activated M2 macrophages, but not from interleukin-4-induced ones, suppressed the D-Gal- and LPS-induced apoptosis of primary hepatocytes and promoted their proliferation in vitro. The unique combination of MCP-1/sSiglec-9 ameliorates rat ALF by inhibiting hepatocellular apoptosis and promoting liver regeneration through the induction of anti-inflammatory/tissue-repairing M2 macrophages.

The Protective Effect of Cordycepin on D-Galactosamine/Lipopolysaccharide-Induced Acute Liver Injury.

As the major active ingredient of Cordyceps militaris, cordycepin (3′-deoxyadenosine) has been well documented to alleviate inflammation and oxidative stress both in vitro and in vivo. To explore the potential protective effect of cordycepin in fulminant hepatic failure, mice were pretreated with cordycepin for 3 weeks followed by D-galactosamine (GalN)/lipopolysaccharide (LPS) injection. Then we found cordycepin (200 mg/kg) administration elevated survival rate, improved liver function, and suppressed hepatocyte apoptosis and necrosis in mice with severe hepatic damage by GalN/LPS treatment. Further, cordycepin inhibited hepatic neutrophil and macrophage infiltration and prevented proinflammatory cytokine production possibly through suppressing TLR4 and NF-κB signaling transduction. The blockade of reactive oxygen species (ROS) and lipid peroxidation production by cordycepin was associated with the decrease of NAD(P)H oxidase (NOX) activity. Besides, cordycepin significantly prevented excessive autophagy induced by GalN/LPS in the liver. These data suggested that cordycepin could be a promising therapeutic agent for GalN/LPS-induced hepatotoxicity.

Pretreatment Donors after Circulatory Death with Simvastatin Alleviates Liver Ischemia Reperfusion Injury through a KLF2-Dependent Mechanism in Rat.

Objective Severe hepatic ischemia reperfusion injury (IRI) can result in poor short- and long-term graft outcome after transplantation. The way to improve the viability of livers from donors after circulatory death (DCD) is currently limited. The aim of the present study was to explore the protective effect of simvastatin on DCD livers and investigate the underlying mechanism. Methods 24 male rats randomly received simvastatin or its vehicle. 30 min later, rat livers were exposed to warm ischemia in situ for 30 min. Livers were removed and cold-stored in UW solution for 24 h, subsequently reperfused for 60 min with an isolated perfused rat liver system. Liver injury was evaluated during and after warm reperfusion. Results Pretreatment of DCD donors with simvastatin significantly decreased IRI liver enzyme release, increased bile output and ATP, and ameliorated hepatic pathological changes. Simvastatin maintained the expression of KLF2 and its protective target genes (eNOS, TM, and HO-1), reduced oxidative stress, inhibited innate immune responses and inflammation, and increased the expression of Bcl-2/Bax to suppress hepatocyte apoptosis compared to DCD control group. Conclusion Pretreatment of DCD donors with simvastatin improves DCD livers' functional recovery probably through a KLF2-dependent mechanism. These data suggest that simvastatin may provide a potential benefit for clinical DCD liver transplantation.

Inhibition of Hepatocyte Apoptosis: An Important Mechanism of Corn Peptides Attenuating Liver Injury Induced by Ethanol.

In this study, the effects of mixed corn peptides and synthetic pentapeptide (QLLPF) on hepatocyte apoptosis induced by ethanol were investigated in vivo. QLLPF, was previously characterized from corn protein hydrolysis, which had been shown to exert good facilitating alcohol metabolism activity. Mice were pre-treated with the mixed corn peptides and the pentapeptide for 1 week and then treated with ethanol. After treatment of three weeks, the biochemical indices and the key ethanol metabolizing enzymes, the serum TNF-α, liver TGF-β1 concentrations and the protein expressions related to apoptosis were determined. We found that the Bcl-2, Bax and cytochrome c expressions in the intrinsic pathway and the Fas, FasL and NF-κB expressions in the extrinsic pathway together with higher TNF-α and TGF-β1 concentrations were reversed compared with the model group by both the mixed corn peptides and the pentapeptide. The activation of caspase3 was also suppressed. Additionally, apoptosis was further confirmed with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and the TUNEL assay demonstrated peptides suppressed hepatocyte apoptosis. Our results suggest that apoptosis induced by ethanol is alleviated in response to the treatment of corn peptides, potentially due to reversing the related protein expression.

Fuzheng Huayu recipe alleviates hepatic fibrosis via inhibiting TNF-α induced hepatocyte apoptosis.

BackgroundWhat was the relationship of Fuzheng Huayu recipe (FZHY) inhibiting hepatocyte apoptosis and HSC activation at different stage of liver fibrosis? In order to answer this question, the study was carried out to dynamically observe FZHY’s effect on hepatocyte apoptosis and HSC activation and further explored underling mechanism of FZHY against hepatocyte apoptosis.MethodsMice were randomly divided into four groups: normal, model, FZHY, and N-acetylcystein (NAC) groups. Acute hepatic injury and liver fibrosis in mice were induced by CCl4. Three days before the first CCl4 injection, treatment with FZHY powder or NAC respectively was started. In vitro, primary hepatocytes were pretreated with FZHY medicated serum or Z-VAD-FMK and then incubated with ActD and TNF-α. Primary HSCs were treated with DNA from apoptotic hepatocytes incubated by Act D/TNF-α or FZHY medicated. Liver sections were analyzed for HE staining and immunohistochemical evaluation of apoptosis. Serum ALT and AST, Alb content and TNF-α expression in liver tissue were detected. Hyp content was assayed and collagen deposition was visualized. Expressions of α-SMA and type I collagen were analyzed by immunofluorescence and immunoblotting. Flow cytometry, immunofluorescence, and DNA ladder for hepatocyte apoptosis and immunoblotting for TNF-R1, Bcl-2 and Bax were also analyzed.ResultsMice showed characteristic features of massive hepatocytes apoptosis in early stage of liver injury and developed severe hepatic fibrosis in later phase. FZHY treatment significantly alleviated acute liver injury and hepatocyte apoptosis, and inhibited liver fibrosis by decreasing α-SMA expression and hepatic Hyp content. In vitro, primary hepatocytes were induced by TNF-α and Act D. The anti-apoptotic effect of FZHY was generated by reducing TNFR1 expression and balancing the expressions of Bcl-2 and Bax. Meanwhile, the nuclear DNA from apoptotic hepatocytes stimulated HSC activation in a dose dependent manner, and the DNA from apoptotic hepatocytes treated with FZHY or Z-VAD-FMK reduced HSC activation and type I collagen expression.ConclusionThese findings suggested that FZHY suppressed hepatocyte apoptosis through regulating mediators in death receptor and mitochondrial pathways, and the effect of FZHY on hepatocyte apoptosis might play an important role in inhibiting liver fibrosis.

Hepatocyte growth factor improves survival after partial hepatectomy in cirrhotic rats suppressing apoptosis of hepatocytes

Liver failure after hepatic resection is still a critical issue in the treatment of hepatic tumors in patients with liver cirrhosis. In the current study, the effect of hepatocyte growth factor (HGF) gene transfer, which is a multipotent growth factor, was examined in rats with liver cirrhosis that underwent 2/3 partial hepatectomy (PH). Rats were treated with 1 mL of 1% dimethylnitrosoamine (DMN) 3 consecutive days per week for 4 weeks and then received a 2/3 PH. Three days before the PH, human HGF gene plasmid (20 microg) encapsulated in hemagglutinating virus of Japan (HVJ)-liposome was administered through a direct injection in the portal vein. Control cirrhotic rats received empty HVJ-liposome in the same manner. HGF gene transfer significantly improved survival after PH in the cirrhotic rats, and it stimulated BrdU uptake in hepatocytes. Although the HGF gene transfer did not change the liver regeneration rate after PH, it suppressed hepatocyte apoptosis and upregulated an antiapoptotic protein, Bcl-xl, but it did not affect the expression of Bax, which is a proapoptotic protein. HGF gene transfer to cirrhotic livers improves liver failure-associated death after PH upregulating expression of an antiapoptotic protein, Bcl-xl.

C‐Myc partially mediates IFNγ‐induced apoptosis in the primary hepatocyte

Interferon-gamma (IFNgamma) is a central component of the complex cytokine and inflammatory response that contributes to liver cell injury in hepatitis. We report that in the primary hepatocyte IFNgamma synergizes with the mechanistically distinct apoptotic stimuli CD95, tumour necrosis factor-alpha (TNFalpha) and UV-irradiation. For the first time in primary hepatocytes, we show that IFNgamma-mediated apoptotic signalling requires the cell surface interaction of CD95 and its ligand, and we demonstrate that IFNgamma induces soluble CD95 ligand release from hepatocyte monolayers. Utilizing c-myc phosphorothioate antisense fragments, we suppresses hepatocyte apoptosis induced by IFNgamma. In summary, we identify apoptotic pathways that contribute to IFNgamma-mediated cell death. The hepatocellular response to IFNgamma signalling can be modulated by cytokines and by the interruption of CD95 interaction with its ligand. We present evidence to suggest that c-myc contributes to IFNgamma signalling.

Adenoviral transfection of hepatocytes with the thioredoxin gene confers protection against apoptosis and necrosis

A recombinant adenovirus vector containing the human thioredoxin (TRX) gene was constructed using the Cre- loxP recombination system and used to transfect rat hepatocytes with very high efficiency. The TRX gene was expressed in a dose-dependent manner and significantly modulated rat cellular functions. The TRX gene conferred resistance to oxidative stress, such as hydrogen peroxide treatment, on the host hepatocytes. FACS analysis of DNA fragmentation showed that the TRX gene suppressed hepatocyte apoptosis. It also significantly extended the life span of hepatocytes cultured conventionally on polystyrene plates. Liver-specific functions were maintained in the viability-modulated hepatocytes. Moreover, TRX expression did not affect hepatocyte spheroid formation and it extensively suppressed necrosis in the internal cells. Thus, the transfection of hepatocytes with the TRX gene successfully confers global maintenance of liver functions. These findings provide important information for the development of bioartificial liver support systems and gene therapy for liver diseases.

Role of cytokines in non-genotoxic hepatocarcinogenesis: cause or effect?

Chemicals with the potential to cause cancer through damaging DNA can be readily identified in a range of in vitro screens that detect genotoxicity. However, many carcinogens are non-genotoxic yet cause rodent tumours, particularly in the liver. Some non-genotoxic carcinogens such as the peroxisome proliferators (PPs) act directly to cause liver growth and proliferation, whereas others such as carbon tetrachloride cause liver damage, followed by regenerative hyperplasia. Current data support a role for cytokines such as tumour necrosis factor α (TNFα) and interleukin 1 (IL1) in hepatocarcinogenesis. However, these data give rise to conflicting hypotheses; in some experimental models, TNFα appears to mediate damage, whereas in others it is postulated to play a role in tissue repair. Recently, we have shown that TNFα acting via TNFα receptor 1 and p38 MAP kinase suppresses hepatocyte apoptosis. However, when new protein synthesis is disabled, TNFα becomes a death signal. An understanding of the role of cytokines in rodent hepatocarcinogenesis will allow the development of markers that can be used to identify, at an early stage, those chemicals with the potential to induce rodent tumours.