Dissection of the multiple mechanisms of TNF-alpha-induced apoptosis in liver injury

Subdiaphragmatic vagotomy promotes tumor growth and reduces survival via TNFα in a murine pancreatic cancer model

This study analyses the effects of vagotomy on tumor growth and survival in a murine, pancreatic cancer model in wild-type and TNFα-knockout (−/−) mice.

Throughout many operative procedures in the upper gastrointestinal tract the partial or complete transection of the vagus nerve or its local nerve fibers is unavoidable. Thereby its anti-inflammatory effects in residual tumor tissue may get lost. This effect may be mediated by tumor-associated macrophages (TAM) secreting TNFα.

In an orthotopic murine pancreatic cancer model subdiaphragmatic vagotomy versus sham surgery was performed. The impact on tumor growth was monitored in wild type and TNFα −/− mice using MRI. TAMs as well as expression levels of TNFα were analyzed using immunohistochemistry. The role of TNFα on tumor growth and migration was examined in vitro. Vagotomised mice showed increased tumor growth with macroscopic features of invasive growth and had a shorter survival time. The loss of vagal modulation led to significantly increased TNFα levels in tumors and considerably elevated numbers of TAMs. In vitro TNFα significantly stimulated growth (p < 0.05) and migration (p < 0.05) of pancreatic cancer cells. TNFα −/− mice survived significantly longer after tumor implantation (p < 0.05), with vagotomy not affecting the prognosis of these animals (p > 0.05).

Vagotomy can increase tumor growth and worsen survival in a murine pancreatic cancer model mediated through TAMs and TNFα. Hence, the suppression of TAMs and the modulation of TNFα dependent pathways could offer new perspectives in immunotherapies of pancreatic cancer patients especially with remaining vital tumor cells and lost vagal modulation.

Anti-Inflammatory, Antiapoptotic and Proproliferative Effects of Vitis vinifera Seed Ethanolic Extract in the Liver of Streptozotocin-Nicotinamide-Induced Type 2 Diabetes in Male Rats

OBJECTIVES

Consumption of Vitis vinifera seed has been reported to ameliorate liver pathology in diabetes mellitus; however, the mechanisms underlying its effects remain unknown. In this study, the anti-inflammatory, anti-apoptotic and pro-proliferative effects of the ethanolic seed extract of V. vinifera (VVSEE) in the liver in cases of diabetes were identified.

METHODS

Adult male rats with streptozotocin-nicotinamide-induced diabetes were given 50, 100 or 200 mg/kg body weight VVSEE orally for 28 days. At the end of the treatment, body weights were determined, and the blood was collected for analyses of fasting blood glucose, insulin and liver enzyme levels. Following sacrifice, livers were harvested and their wet weights and glycogen contents were measured. Histologic appearances of the livers were observed under light microscopy, and the expression and distribution of inflammatory, apoptosis and proliferative markers in the livers were identified by molecular biologic techniques.

RESULTS

Treatment of rats with diabetes by VVSEE attenuates decreased body weight, liver weight and liver glycogen content. Additionally, increases in fasting blood glucose levels and liver enzyme levels and decreases in serum insulin levels were ameliorated. Lesser histopathologic changes were also observed: decreased inflammation and apoptosis, as indicated by decreased levels of inflammatory markers (TNF-α, NF-Kβ, IKK-β, IL-6, IL-1β) and apoptosis markers (caspase-3, caspase-9 and Bax). VVSEE treatment induces increase in hepatocyte regeneration, as indicated by increased PCNA and Ki-67 distribution in the livers of rats with diabetes. Several molecules identified in VVSEE via gas chromatography mass spectrometry might contribute to these effects.

CONCLUSIONS

The anti-inflammatory, anti-apoptotic and pro-proliferative effects of VVSEE could account for its hepatoprotective actions in diabetes.

Curcumin attenuates lipopolysaccharide/d-galactosamine-induced acute liver injury by activating Nrf2 nuclear translocation and inhibiting NF-kB activation

Curcumin, a polyphenol in curry spice isolated from the rhizome of turmeric, has been reported to possess versatile biological properties including anti-inflammatory, anti-oxidant, antifibrotic, and anticancer activities. In this study, the hepatoprotective effect of curcumin was investigated in lipopolysaccharide (LPS)/d-galactosamine (d-GalN)-induced acute liver injury (ALI) in rats. Experimental ALI was induced with an intraperitoneal (ip) injection of sterile 0.9% sodium chloride (NaCl) solution containing 8μg LPS and 800mg/kg d-GalN. Curcumin was administered once daily starting three days prior to LPS/d-GalN treatment. Results indicated that curcumin could attenuate hepatic pathological damage, decrease serum ALT and AST levels, and reduce malondialdehyde (MDA) content in experimental ALI rats. Moreover, higher dosages of curcumin pretreatment inhibited NF-κB activation and reduced serum TNF-α and liver TNF-α levels induced by LPS/d-GalN ip injection. Furthermore, we found that curcumin up-regulated the expression of nuclear Nrf2 and Nrf2-dependent antioxidant defense genes including heme oxygenase-1 (HO-1), glutamate-cysteine ligase (GCLC), NAD(P)H dehydrogenase, and quinone (NQO-1) in a dose-dependent manner. Our results showed that curcumin protected experimental animals against LPS/d-GalN-induced ALI through activation of Nrf2 nuclear translocation and inhibition of NF-κB activation.

Endogenous AMPK acts as a detrimental factor in fulminant hepatitis via potentiating JNK-dependent hepatocyte apoptosis

The energy sensor AMP-activated protein kinase (AMPK) is crucial for energy homeostasis. Recent studies have revealed that AMPK is involved in various energy-intensive pathological processes such as inflammation and apoptosis. The physiological functions of hepatic AMPK have been well studied, but the pathological significance of AMPK in liver disorders remains largely unknown. In the present study, the phosphorylation status and the roles of AMPK were investigated in mice with lipopolysaccharide (LPS)/d-galactosamine (D-Gal)-induced fulminant hepatitis. The experimental data indicated that the phosphorylation of hepatic AMPK increased in mice with LPS/D-Gal-induced fulminant hepatitis. Pretreatment with the AMPK inhibitor compound C enhanced the early production of pro-inflammatory cytokines but suppressed the late activation of the caspase cascade, reduced the number of TUNEL-positive cells, decreased the elevation of aminotransferases, alleviated the histological abnormalities and improved the survival rate of LPS/D-Gal-insulted mice. Pretreatment with compound C suppressed LPS/D-Gal-induced phosphorylation of JNK. Inhibition of JNK alleviated LPS/D-Gal-induced liver injury, but the level of p53 remained unchanged in mice exposed to LPS/D-Gal. Post-insult treatment with the AMPK activator A-769662 further increased the phosphorylation levels of AMPK and JNK, enhanced hepatocyte apoptosis and deteriorated liver injury, all of these effects could be reversed by co-administration of the AMPK inhibitor or JNK inhibitor. Interestingly, post-insult treatment with the AMPK inhibitor also resulted in beneficial outcomes. These data suggested that AMPK might be a late detrimental factor in LPS/D-Gal-induced hepatitis via potentiating JNK-dependent hepatocyte apoptosis and AMPK might become a pharmacological target for the intervention of fulminant hepatitis.

Protective effects of morin on lipopolysaccharide/d-galactosamine-induced acute liver injury by inhibiting TLR4/NF-κB and activating Nrf2/HO-1 signaling pathways

Morin, a bioactive flavonoid extracted from the bark of Moraceae plants and many medicinal herbs, has anti-inflammatory and antioxidative effects. In this research, we explored the protective effects of morin against lipopolysaccharide (LPS) and d-galactosamine (D-GalN) induced acute liver injury in mice. Mice were given an intraperitoneal injection of morin before LPS and D-GalN treatment and the HepG2 cells were only given morin to investigate its effects. The results showed that morin markedly inhibited the production of serum alanine transaminase (ALT), aspartate aminotransferase (AST), interleukin-6 (IL-6), tumor necrosis factor (TNF-α) and hepatic TNF-α, IL-6, and myeloperoxidase (MPO) induced by LPS/D-GalN. In order to evaluate morin effect in the future, we investigated the expression of nuclear factor E2 related factor 2 (Nrf2), nuclear factor-kappaB (NF-κB), toll like receptor 4 (TLR4) on liver injury. Taken together, these results suggested that morin could exert the anti-inflammatory and anti-oxidative effects against LPS/D-GalN-induced acute liver injury by activating Nrf2 signal pathways and inhibiting NF-κB activation.

Preconditioning methods in the management of hepatic ischemia reperfusion- induced injury: Update on molecular and future perspectives

Hepatic IR (ischemia reperfusion) injury is a commonly encountered obstacle in the post-operative management of hepatic surgery. Hepatic IR occurs during 'Pringle maneuver' for reduction of blood loss or during a brief period of cold storage followed by reperfusion of liver grafts. The stress induced during hepatic IR, triggers a spectrum of cellular responses leading to the varying degrees of hepatic complications which in turn affect the post operative care. Different preconditioning methods either activate or subdue different sets of molecular signals, resulting in varied levels of protection against hepatic IR injury. Yet, there is a serious lacuna in the knowledge regarding the choice of preconditioning methods and the resulting molecular changes in order to assess the efficiency and choice of these methods correctly. This review provides an update on the various preconditioning approaches such as surgical/ischemic, antioxidant, pharmaceutical and genetic preconditioning strategies published during last six years (2009-2015). Further, we discuss the attenuation or inhibition of specific inflammatory, apoptotic and necrotic markers in the various experimental models of liver IR subjected to different preconditioning strategies. While enlisting the controversies in the ischemic preconditioning strategy, we bring out the uncertainties in the existing molecular targets and their reliability in the attenuation of hepatic IR injury. Future research studies would include the novel preconditioning strategies employ i) the targeted gene silencing of key molecular targets inducing IR, ii) hyper expression of beneficial molecular signals against IR via gene transfer techniques. The above studies would see the combination of these latest techniques with the established preconditioning strategies for better post-operative hepatic management.

The protective effects of Shikonin on lipopolysaccharide/d-galactosamine-induced acute liver injury via inhibiting MAPK and NF-κB and activating Nrf2/HO-1 signaling pathways

Shikonin (SHK) has various biological and pharmacological activities, including anticancer, antibacterial and anti-inflammation activities.

Peripheral Organs of Dengue Fatal Cases Present Strong Pro-Inflammatory Response with Participation of IFN-Gamma-, TNF-Alpha- and RANTES-Producing Cells

Dengue disease is an acute viral illness caused by dengue virus (DENV) that can progress to hemorrhagic stages leading to about 20000 deaths every year worldwide. Despite many clinical investigations regarding dengue, the immunopathogenic process by which infected patients evolve to the severe forms is not fully understood. Apart from differences in virulence and the antibody cross reactivity that can potentially augment virus replication, imbalanced cellular immunity is also seen as a major concern in the establishment of severe dengue. In this context, the investigation of cellular immunity and its products in dengue fatal cases may provide valuable data to help revealing dengue immunopathogenesis. Here, based in four dengue fatal cases infected by the serotype 3 in Brazil, different peripheral organs (livers, lungs and kidneys) were studied to evaluate the presence of cell infiltrates and the patterns of local cytokine response. The overall scenario of the studied cases revealed a considerable systemic involvement of infection with mononuclear cells targeted to all of the evaluated organs, as measured by immunohistochemistry (IHC). Quantification of cytokine-expressing cells in peripheral tissues was also performed to characterize the ongoing inflammatory process by the severe stage of the disease. Increased levels of IFN-γ- and TNF-α-expressing cells in liver, lung and kidney samples of post-mortem subjects evidenced a strong pro-inflammatory induction in these tissues. The presence of increased RANTES-producing cell numbers in all analyzed organs suggested a possible link between the clinical status and altered vascular permeability. Co-staining of DENV RNA and IFN-γ or TNF-α using in situ hibridization and IHC confirmed the virus-specific trigger of the pro-inflammatory response. Taken together, this work provided additional evidences that corroborated with the traditional theories regarding the “cytokine storm” and the occurrence of uneven cellular immunity in response to DENV as major reasons for progress to severe disease.

Questions and controversies: the role of necroptosis in liver disease

Acute and chronic liver injury results in hepatocyte death and turnover. If injury becomes chronic, the continuous cell death and turnover leads to chronic inflammation, fibrosis and ultimately cirrhosis and hepatocellular carcinoma. Controlling liver cell death both in acute injury, to rescue the liver from acute liver failure, and in chronic injury, to curb secondary inflammation and fibrosis, is of paramount importance as a therapeutic strategy. Both apoptosis and necrosis occur in the liver, but the occurrence of necroptosis in the liver and its contribution to liver disease is controversial. Necroptosis is a form of regulated necrosis which occurs in certain cell types when caspases (+/-cIAPs) are inhibited through the RIPK1-RIPK3 activation of MLKL. The occurrence of necroptosis in the liver has recently been examined in multiple liver injury models with conflicting results. The aim of this review is to summarize the published data with an emphasis on the controversies and remaining questions in the field.

Brown seaweeds protect against azoxymethane-induced hepatic repercussions through up-regulation of peroxisome proliferator-activated receptor gamma and attenuation of oxidative stress

CONTEXT

Seaweeds of the genera Turbinaria and Padina have long been used as food and in traditional medicine for treating several diseases.

OBJECTIVE

The current study determines the protective efficacy of the brown seaweeds Turbinaria ornata (Turner) J. Agardh (Sargassaceae) and Padina pavonia (Linnaeus) J.V. Lamouroux (Dictyotaceae) against liver injury induced by azoxymethane (AOM).

MATERIALS AND METHODS

Male Swiss mice received 10 mg/kg AOM once a week for two consecutive weeks and then 100 mg/kg daily dose of either T. ornata or P. pavonia ethanolic extract. Thirteen weeks after the first AOM administration and 24 h after the last treatment, overnight fasted mice were sacrificed and samples collected.

RESULTS

Compared with the AOM group, both T. ornata and P. pavonia significantly decreased the activity of aminotransferases and the concentration of bilirubin while increased albumin levels in the serum. The antioxidative effect of both extracts was observed from the increased activity of superoxide dismutase and glutathione peroxidase activities in the liver, both of which were decreased by AOM. Moreover, the levels of malondialdehyde and nitric oxide were reduced, and histological findings also confirmed the antihepatotoxic activity. In addition, treatment with T. ornata and P. pavonia significantly increased PPARγ and decreased NF-κB expression in the liver of AOM-administered mice.

DISCUSSION AND CONCLUSION

Our findings indicate that the protective function of T. ornata and P. pavonia on AOM-induced liver injury may be possibly exerted by multiple pathways including abolishment of inflammation and oxidative damage, and activation of PPARγ.

Elevation of Alanine Aminotransferase Activity Occurs after Activation of the Cell-Death Signaling Initiated by Pattern-Recognition Receptors ‎but before Activation of Cytolytic Effectors in NK or CD8+ T Cells in the Liver During Acute HCV Infection

Pattern-recognition receptors (PRRs) promote host defenses against HCV infection by binding to their corresponding adapter molecules leading to the initiation of innate immune responses including cell death. We investigated the expression of PRR genes, biomarkers of liver cell-death, and T cell and NK cell activation/inhibition-related genes in liver and serum obtained from three experimentally infected chimpanzees with acute HCV infection, and analyzed the correlation between gene expression levels and clinical profiles. Our results showed that expression of hepatic RIG-I, TLR3, TLR7, 2OAS1, and CXCL10 mRNAs was upregulated as early as 7 days post-inoculation and peaked 12 to 83 days post-inoculation. All of the three HCV infected chimpanzees exhibited significant elevations of serum alanine aminotransferase (ALT) activity between 70 and 95 days after inoculation. Elevated levels of serum cytokeratin 18 (CK-18) and caspases 3 and 7 activity coincided closely with the rise of ALT activity, and were preceded by significant increases in levels of caspase 3 and caspase 7 mRNAs in the liver. Particularly we found that significant positive auto-correlations were observed between RIG-I, TLR3, CXCL10, 2OAS1, and PD-L1 mRNA and ALT activity at 3 to 12 days before the peak of ALT activity. However, we observed substantial negative auto-correlations between T cell and NK cell activation/inhibition-related genes and ALT activity at 5 to 32 days after the peak of ALT activity. Our results indicated cell death signaling is preceded by early induction of RIG-I, TLR3, 2OAS1, and CXCL10 mRNAs which leads to elevation of ALT activity and this signaling pathway occurs before the activation of NK and T cells during acute HCV infection. Our study suggests that PRRs and type I IFN response may play a critical role in development of liver cell injury related to viral clearance during acute HCV infection.

Pediatric Hodgkin lymphoma: biomarkers, drugs, and clinical trials for translational science and medicine

Hodgkin lymphoma (HL) is a lymphoid malignancy that is typically derived from germinal-center B cells. EBV infection, mutations in NF-κB pathway genes, and genetic susceptibility are known risk factors for developing HL. CD30 and NF-κB have been identified as potential biomarkers in pediatric HL patients, and these molecules may represent therapeutic targets. Although current risk adapted and response based treatment approaches yield overall survival rates of >95%, treatment of relapse or refractory patients remains challenging. Targeted HL therapy with the antibody-drug conjugate Brentuximab vedotin (Bv) has proven to be superior to conventional salvage chemotherapy and clinical trials are being conducted to incorporate Bv into frontline therapy that substitutes Bv for alkylating agents to minimize secondary malignancies. The appearance of secondary malignancies has been a concern in pediatric HL, as these patients are at highest risk among all childhood cancer survivors. The risk of developing secondary leukemia following childhood HL treatment is 10.4 to 174.8 times greater than the risk in the general pediatric population and the prognosis is significantly poorer than the other hematological malignancies with a mortality rate of nearly 100%. Therefore, identifying clinically valuable biomarkers is of utmost importance to stratify and select patients who may or may not need intensive regimens to maintain optimal balance between maximal survival rates and averting late effects. Here we discuss epidemiology, risk factors, staging, molecular and genetic prognostic biomarkers, treatment for low and high-risk patients, and the late occurrence of secondary malignancies in pediatric HL.

Caspase Inhibition Prevents Tumor Necrosis Factor-α-Induced Apoptosis and Promotes Necrotic Cell Death in Mouse Hepatocytes in Vivo and in Vitro

How different cell death modes and cell survival pathways cross talk remains elusive. We determined the interrelation of apoptosis, necrosis, and autophagy in tumor necrosis factor (TNF)-α/actinomycin D (ActD) and lipopolysaccharide/D-galactosamine (GalN)-induced hepatotoxicity in vitro and in vivo. We found that TNF-α/ActD-induced apoptosis was completely blocked by a general caspase inhibitor ZVAD-fmk at 24 hours but hepatocytes still died by necrosis at 48 hours. Inhibition of caspases also protected mice against lipopolysaccharide/GalN-induced apoptosis and liver injury at the early time point, but this protection was diminished after prolonged treatment by switching apoptosis to necrosis. Inhibition of receptor-interacting protein kinase (RIP)1 by necrostatin 1 partially inhibited TNF-α/ZVAD-induced necrosis in primary hepatocytes. Pharmacologic inhibition of autophagy or genetic deletion of Atg5 in hepatocytes did not protect against TNF-α/ActD/ZVAD-induced necrosis. Moreover, pharmacologic inhibition of RIP1 or genetic deletion of RIP3 failed to protect and even exacerbated liver injury after mice were treated with lipopolysaccharide/GalN and a pan-caspase inhibitor. In conclusion, our results suggest that different cell death mode and cell survival pathways are closely integrated during TNF-α-induced liver injury when both caspases and NF-κB are blocked. Moreover, results from our study also raised concerns about the safety of currently ongoing clinical trials that use caspase inhibitors.

Characterization of transcription factor response kinetics in parallel

BACKGROUND

Transcription factors (TFs) are effectors of cell signaling pathways that regulate gene expression. TF networks are highly interconnected; one signal can lead to changes in many TF levels, and one TF level can be changed by many different signals. TF regulation is central to normal cell function, with altered TF function being implicated in many disease conditions. Thus, measuring TF levels in parallel, and over time, is crucial for understanding the impact of stimuli on regulatory networks and on diseases.

RESULTS

Here, we report the parallel analysis of temporal TF level changes due to multiple stimuli in distinct cell types. We have analyzed short-term dynamic changes in the levels of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), signal transducer and activator of transcription 3 (Stat3), cAMP response element-binding protein (CREB), glucocorticoid receptor (GR), and TATA binding protein (TBP), in breast and liver cancer cells after tumor necrosis factor-alpha (TNF-α) and palmitic acid (PA) exposure. In response to both stimuli, NF-kB and CREB levels were increased, Stat3 decreased, and TBP was constant. GR levels were unchanged in response to TNF-α stimulation and increased in response to PA treatment.

CONCLUSIONS

Our results show significant overlap in signaling initiated by TNF-α and by PA, with the exception that the events leading to PA-mediated cytotoxicity likely also include induction of GR signaling. These results further illuminate the dynamics of TF responses to cytokine and fatty acid exposure, while concomitantly demonstrating the utility of parallel TF measurement approaches in the analysis of biological phenomena.

Hepatoprotective effects of AdipoRon against d-galactosamine-induced liver injury in mice

Adiponectin is an antidiabetic and antiatherogenic adipokine, which plays distinct roles in the balance of energy homoeostasis. As an insulin sensitizing hormone, adiponectin exerts multiple biological effects by the specific receptors (AdipoR1 and AdipoR2), through activation of AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor (PPAR)α pathways. AdipoRon, an orally active synthetic small-molecule AdipoR agonist, shows very similar effects to adiponectin in vitro and in vivo, which could be a promising therapeutic approach for obesity-related disorders. In view of the regulatory effects of adiponectin or AdipoRon on inflammatory response and energy metabolism, they might be endowed a curative potential for tissue damage. Hence, its effects and possible mechanism were investigated. In vitro studies on hepatocytes (L02) and macrophages (RAW264.7) suggested a protective and anti-inflammatory potential of AdipoRon. The effects were verified in acute hepatic injury mice induced by d-galactosamine (D-GalN): hepatic lesions were restored by AdipoRon or bicyclol (positive reference drug) pretreatment, which were characterized by a significant increase in serological and hepatic biomarkers (AST, ALT, MDA and NOSs). Besides, AdipoRon attenuated the inflammation in the liver, characterized by the dwindling proinflammatory macrophage infiltration, as well as the shrinkage of tumor necrosis factor-α (TNF-α), transforming growth factor beta 1 (TGF-β1), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6); meanwhile conversely promoted AMPK activation by phosphorylation. Combined with liver histopathology, these results demonstrated the hepatoprotective effects of AdipoRon against D-GalN-induced damage, which might be ascribed to the attenuation of inflammation, inhibition of free radical reactions, as well as enhancement of liver energy metabolism.

Protective effects of Ginsenoside Rg1 against carbon tetrachloride-induced liver injury in mice through suppression of inflammation

BACKGROUND

AMP-activated protein kinase (AMPK) is one of the principal cellular energy sensors participating in maintenance of energy balance but recent evidences also suggested that AMPK might be involved in the regulation of inflammation.

STUDY DESIGN/METHODS

Ginsenoside Rg1 (Rg1) was used to investigate the potential roles of AMPK in carbon tetrachloride (CCl4)-induced hepato-toxicity. The experimental data indicated that treatment with Rg1 significantly decreased the elevation of plasma aminotransferases and alleviated hepatic histological abnormalities in CCl4-exposed mice. Treatment with Rg1 also inhibited the increase of myeloperoxidase (MPO) and malondialdehyde (MDA), the induction of TNF-α, IL-6, inducible nitric oxide synthase (iNOS), nitric oxide and the upregulation of matrix metalloproteinase 2 (MMP-2), MMP-3 and MMP-9 in mice exposed to CCl4. These effects were associated with suppressed nuclear accumulation of NF-κB p65.

CONCLUSION

These results indicated that Rg1 effectively suppressed the inflammatory responses and alleviated liver damage induced by CCl4, implying that AMPK activation might be beneficial for ameliorating inflammation-based liver damage.

Excess sphingomyelin disturbs ATG9A trafficking and autophagosome closure

Sphingomyelin is an essential cellular lipid that traffics between plasma membrane and intracellular organelles until directed to lysosomes for SMPD1 (sphingomyelin phosphodiesterase 1)-mediated degradation. Inactivating mutations in the SMPD1 gene result in Niemann-Pick diseases type A and B characterized by sphingomyelin accumulation and severely disturbed tissue homeostasis. Here, we report that sphingomyelin overload disturbs the maturation and closure of autophagic membranes. Niemann-Pick type A patient fibroblasts and SMPD1-depleted cancer cells accumulate elongated and unclosed autophagic membranes as well as abnormally swollen autophagosomes in the absence of normal autophagosomes and autolysosomes. The immature autophagic membranes are rich in WIPI2, ATG16L1 and MAP1LC3B but display reduced association with ATG9A. Contrary to its normal trafficking between plasma membrane, intracellular organelles and autophagic membranes, ATG9A concentrates in transferrin receptor-positive juxtanuclear recycling endosomes in SMPD1-deficient cells. Supporting a causative role for ATG9A mistrafficking in the autophagy defect observed in SMPD1-deficient cells, ectopic ATG9A effectively reverts this phenotype. Exogenous C12-sphingomyelin induces a similar juxtanuclear accumulation of ATG9A and subsequent defect in the maturation of autophagic membranes in healthy cells while the main sphingomyelin metabolite, ceramide, fails to revert the autophagy defective phenotype in SMPD1-deficient cells. Juxtanuclear accumulation of ATG9A and defective autophagy are also evident in tissues of smpd1-deficient mice with a subsequent inability to cope with kidney ischemia-reperfusion stress. These data reveal sphingomyelin as an important regulator of ATG9A trafficking and maturation of early autophagic membranes.

A Mechanistic Review of Cell Death in Alcohol-Induced Liver Injury

Alcoholic liver disease (ALD) is a major health problem in the United States and worldwide without successful treatments. Chronic alcohol consumption can lead to ALD, which is characterized by steatosis, inflammation, fibrosis, cirrhosis, and even liver cancer. Recent studies suggest that alcohol induces both cell death and adaptive cell survival pathways in the liver, and the balance of cell death and cell survival ultimately decides the pathogenesis of ALD. This review summarizes the recent progress on the role and mechanisms of apoptosis, necroptosis, and autophagy in the pathogenesis of ALD. Understanding the complex regulation of apoptosis, necrosis, and autophagy may help to develop novel therapeutic strategies by targeting all 3 pathways simultaneously.

Does Citrulline Have Protective Effects on Liver Injury in Septic Rats?

Citrulline (Cit) supplementation was proposed to serve as a therapeutic intervention to restore arginine (Arg) concentrations and improve related functions in sepsis. This study explored whether citrulline had positive effects on liver injury and cytokine release in the early stages of sepsis. The cecal ligation and puncture (CLP) model was utilized in our study. Rats were divided into four groups: normal, Cit, CLP, and CLP+Cit. The CLP group and CLP+Cit group were separated into 6-, 12-, and 24-hour groups, according to the time points of sacrifice after surgery. Intragastric administration of L-citrulline was applied to rats in Cit and CLP+Cit groups before surgery. Serum AST and ALT levels and levels of MDA, SOD, NO, and iNOS in the liver tissues were evaluated. Plasma concentrations of Cit and Arg were assessed using HPLC-MS/MS. Serum concentrations of cytokines and chemokines were calculated by Luminex. Results showed SOD activities of CLP+Cit groups were significantly higher than that of CLP groups, contrasting with the MDA and NO levels which were significantly lower in CLP+Cit groups than in CLP groups. In addition, plasma concentrations of TNF-α, IL-6, and IL-1β were significantly lower in the CLP+Cit 6-hour group than in the CLP 6-hour group.

Tangeretin Alleviates Cisplatin-Induced Acute Hepatic Injury in Rats: Targeting MAPKs and Apoptosis

Despite its broad applications, cisplatin affords considerable nephro- and hepatotoxicity through triggering inflammatory and oxidative stress cascades. The aim of the current investigation was to study the possible protective effects of tangeretin on cisplatin-induced hepatotoxicity. The impact of tangeretin on cisplatin-evoked hepatic dysfunction and histopathologic changes along with oxidative stress, inflammatory and apoptotic biomarkers were investigated compared to silymarin. Tangeretin pre-treatment significantly improved liver function tests (ALT and AST), inhibited cisplatin-induced lipid profile aberrations (total cholesterol and triglycerides) and diminished histopathologic structural damage in liver tissues. Tangeretin also attenuated cisplatin-induced hepatic inflammatory events as indicated by suppression of tumor necrosis factor-α (TNF-α) and enhancement of interleukin-10 (IL-10). Meanwhile, it lowered malondialdehyde (MDA), nitric oxide (NO) and nuclear factor erythroid 2-related factor 2 (NRF-2) levels with restoration of glutathione (GSH), and glutathione peroxidase (GPx). Regarding mitogen-activated protein kinase (MAPK) pathway, tangeretin attenuated cisplatin-induced increase in phospho-p38, phospho-c-Jun N-terminal kinase (p-JNK) and phospho-extracellular signal-regulated kinase (p-ERK1/2) in liver tissues. In addition, tangeretin downregulated Bax expression with augmentation of Bcl-2 promoting liver cell survival. Our results highlight the protective effects of tangeretin against cisplatin-induced acute hepatic injury via the concerted modulation of inflammation, oxidative stress, MAPKs and apoptotic pathways.

Protective mechanisms of wogonoside against Lipopolysaccharide/D-galactosamine-induced acute liver injury in mice

Wogonoside, a bioactive flavonoid extracted from the root of Scutellaria baicalensis Georgi, has been reported to have anti-inflammatory and antioxidant effects. In this study, we examined the protective effects of wogonoside against lipopolysaccharide (LPS) and D-galactosamine (D-GalN)-induced liver injury in mice. Mice were given an intraperitoneal injection of wogonoside 1h before LPS and d-GalN treatment. The results showed that wogonoside inhibited the production of serum Alanine transaminase (ALT), Aspartate aminotransferase (AST), IL-1β, TNF-α, and hepatic malondialdehyde (MDA) content induced by LPS/GalN. In addition, wogonoside promoted the expression of Nrf2, NQO-1, GCLC, and HO-1. Wogonoside inhibited the expression of hepatic NLRP3, ASC, caspase-1, and IL-1β induced by LPS/GalN. In conclusion, these results suggest that wogonoside protects against LPS/GalN-induced acute liver injury by activating Nrf2 and inhibiting NLRP3 inflammasome activation.

Ischemic preconditioning and remote ischemic preconditioning provide combined protective effect against ischemia/reperfusion injury

AIMS

Our objective was to compare the protective efficacy of ischemic preconditioning (IPC) and remote ischemic preconditioning (RIPC) against liver ischemia/reperfusion injury (IRI) and to evaluate their combined protective effect in mouse liver transplantation (MLT).

MATERIALS AND METHODS

Mice were randomly allocated to sham, IPC, RIPC, or IPC+RIPC groups. The animals were sacrificed at 2h, 24h, and 3 days after reperfusion. Blood samples were collected to evaluate alanine aminotransferase, TNF-α, and innate immune response. Liver tissue samples were obtained for histological evaluation, terminal deoxynucleotidyltransferased UTP nick end labeling, malondialdehyde (MDA) assay.

KEY FINDINGS

Mice given preconditioning measures had significantly lower increase in transaminase, TNF-α expression, MDA formation, liver injury scores, and apoptosis index at 2h, 24h and 3 days after liver transplantation. The percentages of CD11b(+), CD11b(+)CD16/32(+) and CD11b(+) CD16/32(high) in white blood cells at 3 days after MLT were significantly lower than in the sham group. The results of factorial analysis demonstrated no synergistic effect for IPC and RIPC, except for MDA formation 2h after reperfusion (p=0.038).

SIGNIFICANCE

Based on the synergistic and addictive effect on liver IRI induced by MLT between IPC and RIPC, the study suggested ways in which combined preconditionings could be elicited in patients undergoing planned procedures complicated by IRI to support better outcomes.

Ifit1 Protects Against Lipopolysaccharide and D-galactosamine-Induced Fatal Hepatitis by Inhibiting Activation of the JNK Pathway

Treatment of mice with lipopolysaccharide (LPS) and the liver-specific transcriptional inhibitor D-(+)-galactosamine (GalN) induces fatal hepatitis, which is mediated by tumor necrosis factor α (TNF-α) and characterized by massive hepatic apoptosis. Previous studies suggest that GalN increases the sensitivity to LPS/TNF-α, probably by blocking the transcription of protective factors, but the identity of most of these factors is still unclear. Here, we report that Ifit1 protects against LPS/GalN-induced fatal hepatitis. Forced expression of Ifit1 in hepatocytes significantly diminished TNF-α-mediated apoptosis. Moreover, targeted expression of Ifit1 in the liver by recombinant adeno-associated virus serotype 8 protected mice from LPS/GalN-induced lethal hepatitis, which was associated with the inhibition of TNF-α-mediated activation of the c-Jun N-terminal kinase (JNK)-Bim cascade. Furthermore, Ifit1 bound to a scaffolding protein Axin and inhibited its function to mediate JNK activation. Together, our data demonstrate that Ifit1 is a novel protective factor that inhibits LPS/GalN-induced (TNF-α-mediated) fatal hepatitis, suggesting that Ifit1 is a potential therapeutic target for treatment of inflammatory liver diseases.

Endotoxin-stimulated Rat Hepatic Stellate Cells Induce Autophagy in Hepatocytes as a Survival Mechanism

Bacterial lipopolysaccharide (LPS)-stimulated hepatic stellate cells (HSCs) produce many cytokines including IFNβ, TNFα, and IL6, strongly inhibit DNA synthesis, but induce apoptosis of a small number of hepatocytes. In vivo administration of LPS (up to 10 mg/mL) causes modest inflammation and weight loss in rats but not mortality. We determined whether LPS-stimulated HSCs instigate mechanisms of hepatocyte survival. Rats received 10 mg/kg LPS (i.p.) and determinations were made at 6 h. In vitro, HSCs were treated with 100 ng/mL LPS till 24 h. The medium was transferred to hepatocytes, and determinations were made at 0-12 h. Controls were HSC-conditioned medium or medium-containing LPS. LPS treatment of rats caused autophagy in hepatocytes, a physiological process for clearance of undesirable material including injured or damaged organelles. This was accompanied by activation of c-Jun NH2 terminal kinase (JNK) and apoptosis of ~4-5% of hepatocytes. In vitro, LPS-conditioned HSC medium (LPS/HSC) induced autophagy in hepatocytes but apoptosis of only ~10% of hepatocytes. While LPS/HSC stimulated activation of JNK (associated with cell death), it also activated NFkB and ERK1/2 (associated with cell survival). LPS-stimulated HSCs produced IFNβ, and LPS/HSC-induced autophagy in hepatocytes and their apoptosis were significantly inhibited by anti-IFNβ antibody. Blockade of autophagy, on the other hand, strongly augmented hepatocyte apoptosis. While LPS-stimulated HSCs cause apoptosis of a subpopulation of hepatocytes by producing IFNβ, they also induce cell survival mechanisms, which may be of critical importance in resistance to liver injury during endotoxemia.

Inflammatory regulation of steroid sulfatase: A novel mechanism to control estrogen homeostasis and inflammation in chronic liver disease

BACKGROUND & AIMS

Chronic inflammatory liver diseases are associated with estrogen excess and feminization in men, which is thought to be due to compromised liver function to break down estrogens. The goal of this study is to determine whether the inflammatory induction of steroid sulfatase (STS), which converts inactive estrogen sulfates to active estrogens, may have contributed to the estrogen excess in chronic liver disease.

METHODS

We performed bioinformatic analysis, real-time PCR, immunohistochemistry, and UPLC/MS-MS to analyze hepatic STS expression and serum estrogen levels in patients with chronic liver diseases. The crosstalk between NF-κB pathway and STS-regulated estrogen signaling was investigated by electrophoretic mobility shift assay, chromatin immunoprecipitation, luciferase assay and gene knockdown experiments in human hepatocytes.

RESULTS

Hepatic STS was induced in patients with chronic inflammatory liver diseases, which was accompanied by increased circulating estrogen levels. The human STS gene, but not the mouse Sts gene, was induced by inflammatory stimuli in hepatic cells. Mechanistically, STS was established as a novel NF-κB target gene, whose induction facilitated the conversion of inactive estrogen sulfates to active estrogens, and consequently attenuated the inflammatory response. In contrast, genetic or pharmacological inhibition of STS or a direct blockade of estrogen signaling sensitized liver cells to the transcriptional activation of NF-κB and inflammatory response, possibly through the inhibition of IκB kinase activation.

CONCLUSIONS

Our results suggest a negative feedback loop in chronic inflammatory liver diseases, in which the inflammatory activation of NF-κB induces STS gene expression. The induced STS facilitates the conversion of inactive estrogen sulfates to active estrogens, which in return attenuates the NF-κB-mediated inflammation.

Effects of Persian leek (Allium ampeloprasum) on hepatic lipids and the expression of proinflammatory gene in hamsters fed a high-fat/ high-cholesterol diet

OBJECTIVE

Persian leek is one of the most widely used herbal foods among Iranians. In this study, effects of oral administration of Persian leek on plasma and liver lipids were examined in hamster.

MATERIALS AND METHODS

Male Syrian hamsters were randomly divided into three groups: control (standard diet), high fat control (high-fat/high-cholesterol diet), Persian leek (high-fat/high-cholesterol diet + 1% per weight of diet from dried powdered Persian leek) for 14 weeks.

RESULTS

High fat diet increased plasma and liver lipids as compared to standard diet. Adding Persian leek to the high-fat/high-cholesterol diet resulted in no significant changes in the concentration of the plasma lipids or liver cholesterol. However, liver triglycerides (TG), plasma Alanine aminotransferase and gene expression of tumor necrosis factor- α were decreased in hamsters fed high-fat diet containing Persian leek as compared to high-fat diet only.

CONCLUSION

Persian leek might be considered as a herbal food that can reduce liver TG accumulation induced by high fat diets.

Mangiferin alleviates lipopolysaccharide and D-galactosamine-induced acute liver injury by activating the Nrf2 pathway and inhibiting NLRP3 inflammasome activation

Mangiferin, a glucosylxanthone from Mangifera indica, has been reported to have anti-inflammatory effects. However, the protective effects and mechanisms of mangiferin on liver injury remain unclear. This study aimed to determine the protective effects and mechanisms of mangiferin on lipopolysaccharide (LPS) and D-galactosamine (D-GalN)-induced acute liver injury. Mangiferin was given 1h after LPS and D-GalN treatment. The results showed that mangiferin inhibited the levels of serum ALT, AST, IL-1β, TNF-α, MCP-1, and RANTES, as well as hepatic malondialdehyde (MDA) and ROS levels. Moreover, mangiferin significantly inhibited IL-1β and TNF-α production in LPS-stimulated primary hepatocytes. Mangiferin was found to up-regulate the expression of Nrf2 and HO-1 in a dose-dependent manner. Furthermore, mangiferin inhibited LPS/d-GalN-induced hepatic NLRP3, ASC, caspase-1, IL-1β and TNF-α expression. In conclusion, mangiferin protected against LPS/GalN-induced liver injury by activating the Nrf2 pathway and inhibiting NLRP3 inflammasome activation.

The Lung-Liver Axis: A Requirement for Maximal Innate Immunity and Hepatoprotection during Pneumonia

The hepatic acute-phase response (APR), stimulated by injury or inflammation, is characterized by significant changes in circulating acute-phase protein (APP) concentrations. Although individual functions of liver-derived APPs are known, the net consequence of APP changes is unclear. Pneumonia, which induces the APR, causes an inflammatory response within the airspaces that is coordinated largely by alveolar macrophages and is typified by cytokine production, leukocyte recruitment, and plasma extravasation, the latter of which may enable delivery of hepatocyte-derived APPs to the infection site. To determine the functional significance of the hepatic APR during pneumonia, we challenged APR-null mice lacking hepatocyte signal transducer and activator of transcription 3 (STAT3) and v-rel avian reticuloendotheliosis viral oncogene homolog A (RelA) with Escherichia coli in the airspaces. APR-null mice displayed ablated APP induction, significantly increased mortality, liver injury and apoptosis, and a trend toward increased bacterial burdens. TNF-α neutralization reversed hepatotoxicity, but not mortality, suggesting that APR-dependent survival is not solely due to hepatoprotection. After a milder (nonlethal) E. coli infection, hepatocyte-specific mutations decreased APP concentrations and pulmonary inflammation in bronchoalveolar lavage fluid. Cytokine expression in airspace macrophages, but not other airspace or circulating cells, was significantly dependent on APP extravasation into the alveoli. These data identify a novel signaling axis whereby the liver response enhances macrophage activation and pulmonary inflammation during pneumonia. Although hepatic acute-phase changes directly curb injury induced by TNF-α in the liver itself, APPs downstream of these same signals promote survival in association with innate immunity in the lungs, thus demonstrating a critical role for the lung-liver axis during pneumonia.

Metformin prevents ischemia reperfusion-induced oxidative stress in the fatty liver by attenuation of reactive oxygen species formation

Nonalcoholic fatty liver disease is associated with chronic oxidative stress. In our study, we explored the antioxidant effect of antidiabetic metformin on chronic [high-fat diet (HFD)-induced] and acute oxidative stress induced by short-term warm partial ischemia-reperfusion (I/R) or on a combination of both in the liver. Wistar rats were fed a standard diet (SD) or HFD for 10 wk, half of them being administered metformin (150 mg·kg body wt(-1)·day(-1)). Metformin treatment prevented acute stress-induced necroinflammatory reaction, reduced alanine aminotransferase and aspartate aminotransferase serum activity, and diminished lipoperoxidation. The effect was more pronounced in the HFD than in the SD group. The metformin-treated groups exhibited less severe mitochondrial damage (markers: cytochrome c release, citrate synthase activity, mtDNA copy number, mitochondrial respiration) and apoptosis (caspase 9 and caspase 3 activation). Metformin-treated HFD-fed rats subjected to I/R exhibited increased antioxidant enzyme activity as well as attenuated mitochondrial respiratory capacity and ATP resynthesis. The exposure to I/R significantly increased NADH- and succinate-related reactive oxygen species (ROS) mitochondrial production in vitro. The effect of I/R was significantly alleviated by previous metformin treatment. Metformin downregulated the I/R-induced expression of proinflammatory (TNF-α, TLR4, IL-1β, Ccr2) and infiltrating monocyte (Ly6c) and macrophage (CD11b) markers. Our data indicate that metformin reduces mitochondrial performance but concomitantly protects the liver from I/R-induced injury. We propose that the beneficial effect of metformin action is based on a combination of three contributory mechanisms: increased antioxidant enzyme activity, lower mitochondrial ROS production, and reduction of postischemic inflammation.

Stimulation of Wnt/β-catenin signaling pathway with Wnt agonist reduces organ injury after hemorrhagic shock

BACKGROUND

Hemorrhagic shock is a leading cause of morbidity and mortality in surgery and trauma patients. Despite a large number of preclinical trials conducted to develop therapeutic strategies against hemorrhagic shock, there is still an unmet need for effective therapy for hemorrhage patients. Wnt/β-catenin signaling controls developmental processes and cellular regeneration owing to its central role in cell survival and proliferation. We therefore hypothesized that the activation of Wnt signaling reduces systemic injury caused by hemorrhagic shock.

METHODS

Adult male Sprague-Dawley rats underwent hemorrhagic shock by controlled bleeding of the femoral artery to maintain a mean arterial pressure of 30 mm Hg for 90 minutes, followed by resuscitation with crystalloid equal to two times the shed blood volume. After resuscitation, animals were infused with Wnt agonist (5 mg/kg) or vehicle (20% dimethyl sulfoxide in saline). Blood and tissue samples were collected 6 hours after resuscitation for analysis.

RESULTS

Hemorrhagic shock increased serum levels of aspartate aminotransferase, lactate, and lactate dehydrogenase. Treatment with Wnt agonist significantly reduced these levels by 40%, 36%, and 77%, respectively. Wnt agonist also decreased blood urea nitrogen and creatinine by 34% and 56%, respectively. The treatment reduced lung myeloperoxidase activity and interleukin 6 messenger RNA by 55% and 68%, respectively, and significantly improved lung histology. Wnt agonist treatment increased Bcl-2 protein to sham values and decreased cleaved caspase 3 by 46%, indicating attenuation of hemorrhage-induced apoptosis in the lungs. Hemorrhage resulted in significant reductions of β-catenin protein levels in the lungs as well as down-regulation of a Wnt target gene, cyclin D1, while Wnt agonist treatment preserved these levels.

CONCLUSION

The administration of Wnt agonist attenuated hemorrhage-induced organ injury, inflammation, and apoptosis. This was correlated with the preservation of the Wnt signaling pathway. Thus, Wnt/β-catenin activation could be protective in hemorrhagic shock.

Valproate-induced liver injury: modulation by the omega-3 fatty acid DHA proposes a novel anticonvulsant regimen

Background

The polyunsaturated, ω-3 fatty acid, docosahexaenoic acid (DHA), claims diverse cytoprotective potentials, although via largely undefined triggers. Thus, we currently first tested the ability of DHA to ameliorate valproate (VPA)-evoked hepatotoxicity, to modulate its anticonvulsant effects, then sought the cellular and molecular basis of such actions. Lastly, we also verified whether DHA may kinetically alter plasma levels/clearance rate of VPA.

Methods and Results

VPA (500 mg/kg orally for 14 days in rats) evoked prominent hepatotoxicity that appeared as a marked rise (2- to 4-fold) in serum hepatic enzymes (γ-glutamyl transferase [γ-GT], alanine aminotransferase [ALT], and alkaline phosphatase [ALP]), increased hepatic lipid peroxide (LPO) and tumor necrosis factor-alpha (TNFα) levels, as well as myeloperoxidase (MPO) activity (3- to 5-fold), lowering of serum albumin (40 %), and depletion of liver reduced-glutathione (GSH, 35 %). Likewise, histopathologic examination revealed hepatocellular degeneration, replacement by inflammatory cells, focal pericentral necrosis, and micro/macrovesicular steatosis. Concurrent treatment with DHA (250 mg/kg) markedly blunted the elevated levels of liver enzymes, lipid peroxides, TNFα, and MPO activity, while raising serum albumin and hepatic GSH levels. DHA also alleviated most of the cytologic insults linked to VPA. Besides, in a pentylenetetrazole (PTZ) mouse convulsion model, DHA (250 mg/kg) markedly increased the latency in convulsion evoked by VPA, beyond their individual responses. Lastly, pharmacokinetic studies revealed that joint DHA administration did not alter serum VPA concentrations.

Conclusions

DHA substantially ameliorated liver injury induced by VPA, while also markedly boosted its pharmacologic effects. DHA manipulated definite cellular machinery to curb liver oxidative stress and inflammation, without affecting VPA plasma levels. Collectively, these protective and synergy profiles for DHA propose a superior VPA-drug combination regimen.

The relationship between visfatin, liver inflammation, and acute phase reactants in chronic viral hepatitis B

Chronic viral hepatitis B (CHB) is an important cause of morbidity and mortality. Adipokine stimulation might play an important role in the pathogenesis of chronic inflammation. The aim of this study was to evaluate serum visfatin concentrations and the relationship between visfatin, fibrosis, liver inflammation, and acute phase reactants in CHB patients.The sampling universe of the study consisted of 41 CHB patients and 25 healthy controls. All patients had positive hepatitis B surface antigen (Hepatitis e antigen (HBeAg) positive n: 7, n: 34 HBeAg negative) for at least 6 months and detectable serum HBV DNA. Serum visfatin concentrations were significantly higher in the CHB patients [18.0 ± 10.9 ng dL(-1)] than in the healthy controls [9.4 ± 1.6 ng dL(-1)] [P < 0.001]. On the other hand, fibrinogen and haptoglobin concentrations were significantly lower in CHB patients. A strong negative correlation was observed between serum visfatin concentration, haptoglobin, and fibrinogen levels; however, there was no significant correlation between visfatin, glucose, alanine aminotransferase, aspartate aminotransferase, BMI, Knodell score, fibrosis score, hepatitis B virus DNA, sedimentation, and C-reactive protein. Visfatin concentrations were elevated and visfatin was negatively correlated with haptoglobin and fibrinogen levels in CHB patients.

Caloric restriction mimetic 2-deoxyglucose alleviated lethal liver injury induced by lipopolysaccharide/D-galactosamine in mice

The glycolytic inhibitor 2-deoxyglucose (2-DG) is a calorie restriction (CR) mimetic produces CR-like beneficial effects in both acute and chronic pathological processes, but whether 2-DG is also helpful in critical and life-threatening situation is not known. In the present study, the potential benefits of 2-DG in lipopolysaccharide/D-galactosamine (LPS/D-Gal)-induced lethal liver injury were investigated. The results indicated that treatment with 2-DG suppressed the elevation of plasma aminotransferases, alleviated the histopathological abnormalities and improved the survival rate of LPS/D-Gal-exposed mice. Treatment with 2-DG also suppressed the production of pro-apoptotic cytokine TNF-α, the phosphorylation of JNK, the activation of caspase cascade and the count of TUNEL-positive apoptotic hepatocytes. These data suggested that the CR mimetic 2-DG could also provide beneficial effects in lethal pathological process such as LPS/D-Gal-induced fulminant liver injury.

5-Aminoimidazole-4-carboxamide-1-β-d-ribofuranoside alleviated carbon tetrachloride-induced acute hepatitis in mice

AMP-activated protein kinase (AMPK) is one of the principal cellular energy sensors participating in maintenance of energy balance but recent evidences also suggested that AMPK might be involved in the regulation of inflammation. In the present study, the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) was used to investigate the potential roles of AMPK in carbon tetrachloride (CCl4)-induced acute hepatitis. The experimental data indicated that treatment with AICAR significantly decreased the elevation of plasma aminotransferases and alleviated hepatic histological abnormalities in CCl4-exposed mice. Treatment with AICAR also inhibited the increase of myeloperoxidase (MPO), the induction of TNF-α, IL-6, inducible nitric oxide synthase (iNOS), nitric oxide and the upregulation of matrix metalloproteinase 2 (MMP-2), MMP-3 and MMP-9 in mice exposed to CCl4. These effects were associated with suppressed nuclear accumulation of NF-κB p65. These results indicated that the AMPK activator AICAR effectively suppressed the inflammatory responses and alleviated liver damage induced by CCl4, implying that AMPK activation might be beneficial for ameliorating inflammation-based liver damage.

Protective effect of oroxylin A against lipopolysaccharide and/or D-galactosamine-induced acute liver injury in mice

BACKGROUND

Oroxylin A, a natural flavonoid isolated from Scutellariae baicalensis, has been reported to possess a wide spectrum of pharmacologic activities. However, the effects of oroxylin A on liver injury are poor understood. The purpose of this study was to investigate the effects of oroxylin A on acute liver injury in mice induced by lipopolysaccharide and/or D-galactosamine (LPS and/or D-GalN).

METHODS

Mice acute liver injury model was induced by LPS (50 μg/kg) and/or GalN (800 mg/kg). Serum alanine aminotransferase, aspartate aminotransferase, and tumor necrosis factor-α levels, hepatic tissue histology, malondialdehyde content, and myeloperoxidase activity were analyzed. Meanwhile, nuclear factor kappa B (NF-κB), heme oxygenase-1 (HO-1), and nuclear factor erythroid2-related factor 2 (Nrf2) expression were detected by Western blotting.

RESULTS

The results showed that oroxylin A dose-dependently inhibited LPS and/or GalN-induced serum alanine aminotransferase, aspartate aminotransferase, and tumor necrosis factor-α levels. Hepatic malondialdehyde content and myeloperoxidase activity were also suppressed by oroxylin A. We also found that oroxylin A inhibited LPS and/or GalN-induced toll like receptor 4 (TLR4) expression and NF-κB activation. In addition, oroxylin A upregulated the expression of Nrf2 and HO-1 in a dose-dependent manner.

CONCLUSIONS

In conclusion, oroxylin A protected against LPS and/or GalN-induced liver injury through activating Nrf2 and inhibiting TLR4 signaling pathway.

Acute and chronic immunomodulatory changes in rat liver after fetal and perinatal asphyxia

Hypoxic-ischemic encephalopathy (HIE) caused by fetal and perinatal asphyxia is an important cause of mortality in the neonatal period. Not only will asphyxia affect the brain but also other organs such as the liver and kidneys. Interestingly, it has been shown that liver damage is proportional to the severity of the asphyctic insult, implying an association between liver impairment and HIE. Accordingly, we investigated in an established rat model the acute and chronic hepatic response to both fetal (FA) and perinatal asphyxia (PA). In addition, we assessed whether fetal asphyctic preconditioning (PC) would have any beneficial effect on the liver. Inflammation, ceramide signaling and hepatocellular damage were analyzed in the livers of newborn and adult rats at several short- and long-term time points after both FA and PA. We found that although FA induced an acute inflammatory response, apoptotic mRNA levels and oxidative DNA damage were decreased at 96 h post FA. Whereas increased IL-6 and IL-10 mRNA levels were observed after PA, the combination of FA and PA (PC) attenuated the inflammatory response. Moreover, 6 h after PA anti-apoptotic genes were downregulated and associated with less lipid peroxidation, while preconditioned animals were comparable to controls. In summary, asphyctic PC seems to have an acute protective effect on the liver by modulating the inflammatory, apoptotic and anti-oxidative response. More insight into the hepatic response to asphyxia is necessary, as disturbed hepatic function is associated with metabolic diseases in later life.

Electroacupuncture inhibits apoptosis of splenic lymphocytes in traumatized rats through modulation of the TNF-α/NF-κB signaling pathway

Surgical trauma leads to a severe deterioration of the immune system. Electroacupuncture (EA) may improve the immunodeficiency that occurs following surgery; however, the underlying signaling mechanisms require further study. In the present study, 40 rats were equally randomized into four groups: Control; Control + EA; Trauma; Trauma + EA. EA was applied at the 'Zusanli' (ST36) and 'Lanwei' (Extra37) acupoints, immediately following surgery. The splenic T cells were isolated from the rats 24 h after surgery. The apoptotic rate of the lymphocytes was measured by flow cytometric analysis, and western blotting was used to determine the protein expression levels of caspase-3, caspase-8, tumor necrosis factor (TNF)-α and TNF receptor 1 (TNFR1). The DNA binding activity of nuclear factor (NF)-κB was determined using Trans-AM® ELISA-based kits. The results of the present study showed that surgical trauma induced apoptosis of splenic lymphocytes, and significantly increased the protein expression levels of caspase-3 and caspase-8. This was accompanied by increased expression levels of TNF-α and TNFR1, and a marked reduction in the activity of NF-κB in splenic T cells. Administration of EA significantly decreased the expression levels of caspase-3, caspase-8, TNF-α and TNFR1, elevated the activity of NF-κB, and suppressed the apoptotic rate of the lymphocytes. The data suggests that EA may inhibit the apoptosis of splenic lymphocytes induced by surgical trauma, and ameliorate the postoperative immunosuppression. This may be mediated by the downregulation of TNF-α expression levels and upregulation of the activity of NF-κB.

Anticancer potential of Conium maculatum extract against cancer cells in vitro: Drug-DNA interaction and its ability to induce apoptosis through ROS generation

Objective:

Conium maculatum extract is used as a traditional medicine for cervix carcinoma including homeopathy. However, no systematic work has so far been carried out to test its anti-cancer potential against cervix cancer cells in vitro. Thus, in this study, we investigated whether ethanolic extract of conium is capable of inducing cytotoxicity in different normal and cancer cell lines including an elaborate study in HeLa cells.

Materials and Methods:

Conium's effects on cell cycle, reactive oxygen species (ROS) accumulation, mitochondrial membrane potential (MMP) and apoptosis, if any, were analyzed through flow cytometry. Whether Conium could damage DNA and induce morphological changes were also determined microscopically. Expression of different proteins related to cell death and survival was critically studied by western blotting and ELISA methods. If Conium could interact directly with DNA was also determined by circular dichroism (CD) spectroscopy.

Results:

Conium treatment reduced cell viability and colony formation at 48 h and inhibited cell proliferation, arresting cell cycle at sub-G stage. Conium treatment lead to increased generation of reactive oxygen species (ROS) at 24 h, increase in MMP depolarization, morphological changes and DNA damage in HeLa cells along with externalization of phosphatidyl serine at 48 hours. While cytochrome c release and caspase-3 activation led HeLa cells toward apoptosis, down-regulation of Akt and NFkB inhibited cellular proliferation, indicating the signaling pathway to be mediated via the mitochondria-mediated caspase-3-dependent pathway. CD-spectroscopy revealed that Conium interacted with DNA molecule.

Conclusion:

Overall results validate anti-cancer potential of Conium and provide support for its use in traditional systems of medicine.

New advances in molecular mechanisms and emerging therapeutic targets in alcoholic liver diseases

Alcoholic liver disease is a major health problem in the United States and worldwide. Chronic alcohol consumption can cause steatosis, inflammation, fibrosis, cirrhosis and even liver cancer. Significant progress has been made to understand key events and molecular players for the onset and progression of alcoholic liver disease from both experimental and clinical alcohol studies. No successful treatments are currently available for treating alcoholic liver disease; therefore, development of novel pathophysiological-targeted therapies is urgently needed. This review summarizes the recent progress on animal models used to study alcoholic liver disease and the detrimental factors that contribute to alcoholic liver disease pathogenesis including miRNAs, S-adenosylmethionine, Zinc deficiency, cytosolic lipin-1β, IRF3-mediated apoptosis, RIP3-mediated necrosis and hepcidin. In addition, we summarize emerging adaptive protective effects induced by alcohol to attenuate alcohol-induced liver pathogenesis including FoxO3, IL-22, autophagy and nuclear lipin-1α.

Protective effects of melittin on tumor necrosis factor-α induced hepatic damage through suppression of apoptotic pathway and nuclear factor-kappa B activation

Melittin, a major polypeptide in honeybee venom, have been used to treat inflammatory disease. Various studies have demonstrated the anti-bacterial, anti-viral, anti-inflammatory and anticancer effects of bee venom and melittin. However, the precise mechanism of melittin in liver disease is not yet known. Apoptosis contributes to liver inflammation and fibrosis. Knowledge of the apoptotic mechanisms is important to develop new and effective therapies for treatment of cirrhosis. In the present study, we investigated the anti-apoptotic effect of melittin on tumor necrosis factor (TNF)-α/actinomycin (Act) D-induced apoptosis in hepatocytes. Our results show significant protection from DNA damage by melittin treatment compared with corresponding TNF-α/Act D-treated hepatocytes without melittin. Melittin inhibited TNF-α/Act D-induced activation of the caspase, bcl-2 family of proteins and poly ADP-ribose polymerase (PARP)-1. Our results also indicate that melittin decreased nuclear factor-kappa B (NF-κB) by degradation of phosphorylation of IκB kinase (p-IKK) and NF-κB DNA binding activity in TNF-α/Act D-treated hepatocytes. These results suggest that melittin possesses a potent suppressive effect on apoptotic responses in TNF-α/Act D-treated hepatocytes via the NF-κB pathway.

Obesity and its metabolic complications: the role of adipokines and the relationship between obesity, inflammation, insulin resistance, dyslipidemia and nonalcoholic fatty liver disease

Accumulating evidence indicates that obesity is closely associated with an increased risk of metabolic diseases such as insulin resistance, type 2 diabetes, dyslipidemia and nonalcoholic fatty liver disease. Obesity results from an imbalance between food intake and energy expenditure, which leads to an excessive accumulation of adipose tissue. Adipose tissue is now recognized not only as a main site of storage of excess energy derived from food intake but also as an endocrine organ. The expansion of adipose tissue produces a number of bioactive substances, known as adipocytokines or adipokines, which trigger chronic low-grade inflammation and interact with a range of processes in many different organs. Although the precise mechanisms are still unclear, dysregulated production or secretion of these adipokines caused by excess adipose tissue and adipose tissue dysfunction can contribute to the development of obesity-related metabolic diseases. In this review, we focus on the role of several adipokines associated with obesity and the potential impact on obesity-related metabolic diseases. Multiple lines evidence provides valuable insights into the roles of adipokines in the development of obesity and its metabolic complications. Further research is still required to fully understand the mechanisms underlying the metabolic actions of a few newly identified adipokines.

Cordyceps sinensisPrevents Apoptosis in Mouse Liver with D-Galactosamine/Lipopolysaccharide-Induced Fulminant Hepatic Failure

Cordyceps sinensis (C. sinensis) has long been considered to be an herbal medicine and has been used in the treatment of various inflammatory diseases. The present study examined the cytoprotective properties of C. sinensis on D(+)-galactosamine (GalN)/lipopolysaccharide (LPS)-induced fulminant hepatic failure. Mice were randomly assigned into control, GalN/LPS, CS 20 mg and CS 40 mg groups (C. sinensis, oral gavage, five days/week, four weeks). After receiving saline or C. sinensis, mice were intraperitoneally given GalN (800 mg/kg)/LPS (10 μg/kg). The effects of C. sinensis on TNF-α, IL-10, AST, NO, SOD, and apoptoticrelated proteins after the onset of endotoxin intoxication were determined. Data demonstrated that GalN/LPS increased hepatocyte degeneration, circulating AST, TNF-α, IL-10, and hepatic apoptosis and caspase activity. C. sinensis pre-treatment reduced AST, TNF-α, and NO and increased IL-10 and SOD in GalN/LPS induced fulminant hepatic failure. C. sinensis attenuated the apoptosis of hepatocytes, as evidenced by the TUNEL and capase-3, 6 activity analyses. In summary, C. sinensis alleviates GalN/LPS-induced liver injury by modulating the cytokine response and inhibiting apoptosis. C. sinensis could be used as a potent antioxidant, anti-inflammatory and anti-apoptotic agent to reduce liver injury after the onset of sepsis.