Death receptor-mediated apoptosis and the liver

Cell Death: Mechanisms and Potential Targets in Breast Cancer Therapy

Breast cancer (BC) has become the most life-threatening cancer to women worldwide, with multiple subtypes, poor prognosis, and rising mortality. The molecular heterogeneity of BC limits the efficacy and represents challenges for existing therapies, mainly due to the unpredictable clinical response, the reason for which probably lies in the interactions and alterations of diverse cell death pathways. However, most studies and drugs have focused on a single type of cell death, while the therapeutic opportunities related to other cell death pathways are often neglected. Therefore, it is critical to identify the predominant type of cell death, the transition to different cell death patterns during treatment, and the underlying regulatory mechanisms in BC. In this review, we summarize the characteristics of various forms of cell death, including PANoptosis (pyroptosis, apoptosis, necroptosis), autophagy, ferroptosis, and cuproptosis, and discuss their triggers and signaling cascades in BC, which may provide a reference for future pathogenesis research and allow for the development of novel targeted therapeutics in BC.

ASK1/ p38 axis inhibition blocks the release of mitochondrial "danger signals" from hepatocytes and suppresses progression to cirrhosis and liver cancer

BACKGROUND AND AIMS

Apoptosis Signal-regulating Kinase 1 (ASK1) is activated by various pathological stimuli and induces cell apoptosis through downstream p38 activation. We studied the effect of pharmacological ASK1 inhibition on cirrhosis and its sequelae using comprehensive preclinical in vivo and in vitro systems.

APPROACH AND RESULTS

Short-term (4-6 wk) and long-term (24-44 wk) ASK1 inhibition using small molecule GS-444217 was tested in thioacetamide-induced and BALB/c. Mdr2-/- murine models of cirrhosis and HCC, and in vitro using primary hepatocyte cell death assays. Short-term GS-444217 therapy in both models strongly reduced phosphorylated p38, hepatocyte death, and fibrosis by up to 50%. Profibrogenic release of mitochondrial DAMP mitochondrial deoxyribonucleic acid from dying hepatocytes was blocked by ASK1 or p38 inhibition. Long-term (24 wk) therapy in BALBc.Mdr2 - / - model resulted in a moderate 25% reduction in bridging fibrosis, but not in net collagen deposition. Despite this, the development of cirrhosis was effectively prevented, with strongly reduced p21 + hepatocyte staining (by 72%), serum ammonia levels (by 46%), and portal pressure (average 6.07 vs. 8.53 mm Hg in controls). Extended ASK1 inhibition for 44 wk in aged BALB/c. Mdr2-/- mice resulted in markedly reduced tumor number and size by ~50% compared to the control group.

CONCLUSIONS

ASK1 inhibition suppresses the profibrogenic release of mitochondrial deoxyribonucleic acid from dying hepatocytes in a p38-dependent manner and protects from liver fibrosis. Long-term ASK1 targeting resulted in diminished net antifibrotic effect, but the progression to liver cirrhosis and cancer in BALBc/ Mdr2- / - mice was effectively inhibited. These data support the clinical evaluation of ASK1 inhibitors in fibrotic liver diseases.

Deoxyribonuclease I Alleviates Septic Liver Injury in a Rat Model Supported by Venoarterial Extracorporeal Membrane Oxygenation

Sepsis is an unusual systemic reaction with high mortality and secondary septic liver injury is proposed to be the major cause of mortality. Extracorporeal membrane oxygenation (ECMO) can enhance terminal organ perfusion by elevating circulatory support which is used in severe sepsis patients. However, the interaction of blood components with the biomaterials of the extracorporeal membrane elicits a systemic inflammatory response. Besides, inflammation and apoptosis are the main mediators in the pathophysiology of septic liver injury. Therefore, we investigated the protective effect of Deoxyribonuclease I (DNase I) against septic liver injury supported by ECMO in rats. Sepsis was induced by lipopolysaccharide (LPS) and 24 hours after the administration, the rats were treated with ECMO. Then blood samples and liver tissues were collected. DNase I significantly attenuated the level of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and significantly decreased hepatic levels of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome, myeloperoxidase (MPO), downstream inflammatory factor interleukin-1β (IL-1β) and interleukin-18 (IL-18), and improved neutrophil infiltration. Additionally, DNase I significantly reduced the expression of apoptosis key protein and terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL)-labeled apoptotic hepatocytes. In summary, our findings demonstrated that DNase I alleviates liver injury in ECMO-supported septic rats by reducing the inflammatory and apoptotic responses.

Mechanistic Understanding of D-Glucaric Acid to Support Liver Detoxification Essential to Muscle Health Using a Computational Systems Biology Approach

Liver and muscle health are intimately connected. Nutritional strategies that support liver detoxification are beneficial to muscle recovery. Computational-in silico-molecular systems' biology analysis of supplementation of calcium and potassium glucarate salts and their metabolite D-glucaric acid (GA) reveals their positive effect on mitigation of liver detoxification via four specific molecular pathways: (1) ROS production, (2) deconjugation, (3) apoptosis of hepatocytes, and (4) β-glucuronidase synthesis. GA improves liver detoxification by downregulating hepatocyte apoptosis, reducing glucuronide deconjugates levels, reducing ROS production, and inhibiting β-Glucuronidase enzyme that reduces re-absorption of toxins in hepatocytes. Results from this in silico study provide an integrative molecular mechanistic systems explanation for the mitigation of liver toxicity by GA.

The TNF-α rs361525 and IFN-γ rs2430561 polymorphisms are associated with liver cirrhosis risk: a comprehensive meta-analysis

Background

Inflammation serves as an essential driver of liver cirrhosis (LC) incidence. Accordingly, a meta-analysis was carried out to explore the association between specific polymorphisms in the interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) genes and the incidence of LC based on comparisons of genotype and allele frequencies.

Objectives

To study the relationship between TNF-α rs361525 and IFN-γ rs2430561 polymorphisms and the risk of LC.

Methods

A database search was performed for all studies published as of September 10, 2022. The strength of risk relationships was assessed based on odds ratios (ORs) with 95% confidence intervals (CIs).

Results

Pooled analyses were conducted for one common TNF-α polymorphism (rs361525) as well as one common IFN-γ polymorphism (rs2430561). Both of these SNPs were identified as LC-related risk factors. Specifically, rs361525 was related to LC incidence in both alcoholic liver cirrhosis (OR: 1.86, 95%CI: 1.03-3.34) and hepatitis B virus (HBV)-related cirrhosis cases (OR: 1.44, 95%CI: 1.00-2.06) when using an allelic contrast model. Moreover, rs2430561 was significantly related to LC in an Asian population (OR: 1.45, 95%CI: 1.13-1.86) and in the context of HBV-related cirrhosis (OR: 1.48, 95%CI: 1.13-1.93) when using an allelic contrast model.

Conclusion

These findings indicate that rs361525 and rs2430561 represent LC-related risk factors, although additional large-scale clinical and case-control studies will be vital to confirm these results.

Anticarcinogenic Effects of Isothiocyanates on Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, accounting for about 90% of cases. Sorafenib, lenvatinib, and the combination of atezolizumab and bevacizumab are considered first-line treatments for advanced HCC. However, clinical application of these drugs has also caused some adverse reactions such as hypertension, elevated aspartate aminotransferases, and proteinuria. At present, natural products and their derivatives have drawn more and more attention due to less side effects as cancer treatments. Isothiocyanates (ITCs) are one type of hydrolysis products from glucosinolates (GLSs), secondary plant metabolites found exclusively in cruciferous vegetables. Accumulating evidence from encouraging in vitro and in vivo animal models has demonstrated that ITCs have multiple biological activities, especially their potentially health-promoting activities (antibacterial, antioxidant, and anticarcinogenic effects). In this review, we aim to comprehensively summarize the chemopreventive, anticancer, and chemosensitizative effects of ITCs on HCC, and explain the underlying molecular mechanisms.

Investigation of Lonicera japonica Flos against Nonalcoholic Fatty Liver Disease Using Network Integration and Experimental Validation

Background and objective: Lonicera japonica Flos (LJF) is a well-known traditional herbal medicine that has been used as an anti-inflammatory, antibacterial, antiviral, and antipyretic agent. The potent anti-inflammatory and other ethnopharmacological uses of LJF make it a potential medicine for the treatment of nonalcoholic fatty liver disease (NAFLD). This research is to explore the mechanisms involved in the activity of LJF against NAFLD using network integration and experimental pharmacology. Materials and methods: The possible targets of LJF involved in its activity against NAFLD were predicted by matching the targets of the active components in LJF with those targets involved in NAFLD. The analysis of the enrichment of GO functional annotations and KEGG pathways using Metascape, followed by constructing the network of active components–targets–pathways using Cytoscape, were carried out to predict the targets. Molecular docking studies were performed to further support the involvement of these targets in the activity of LJF against NAFLD. The shortlisted targets were confirmed via in vitro studies in an NAFLD cell model. Results: A total of 17 active components in LJF and 29 targets related to NAFLD were predicted by network pharmacology. Molecular docking studies of the main components and the key targets showed that isochlorogenic acid B can stably bind to TNF-α and CASP3. In vitro studies have shown that LJF down-regulated the TNF-α and CASP3 expression in an NAFLD cell model. Conclusions: These results provide scientific evidence for further investigations into the role of LJF in the treatment of NAFLD.

Protective effects of menthol against sepsis-induced hepatic injury: Role of mediators of hepatic inflammation, apoptosis, and regeneration

Liver dysfunction in sepsis is a major complication that amplifies multiple organ failure and increases the risk of death. Inflammation and oxidative stress are the main mediators in the pathophysiology of sepsis. Therefore, we investigated the role of menthol, a natural antioxidant, against sepsis-induced liver injury in female Wistar rats. Sepsis was induced by cecal ligation and puncture (CLP). Menthol (100 mg/kg) was given intragastric 2 h after CLP. Blood samples and liver tissues were collected 24 h after surgery. Menthol significantly (p < 0.05) attenuated the sepsis-induced elevation in serum liver enzymes and improved the hepatic histopathological changes. Menthol treatment significantly (p < 0.05) decreased hepatic levels of tumor necrosis factor-alpha, malondialdehyde, total nitrite, and cleaved caspase-3. It restored the hepatic levels of superoxide dismutase and reduced glutathione. Additionally, menthol significantly (p < 0.05) increased hepatic levels of B-cell lymphoma 2 (Bcl-2); an anti-apoptotic factor, and proliferating cell nuclear antigen (PCNA), a biomarker of regeneration and survival. Our results showed the therapeutic potential of menthol against liver injury induced by sepsis.

Hepatoprotective Activity of Nelumbo nucifera Gaertn. Seedpod Extract Attenuated Acetaminophen-Induced Hepatotoxicity

The aim is to investigate the effect of lotus (Nelumbo nucifera Gaertn.) seedpod extract (LSE) on acetaminophen (APAP)-induced hepatotoxicity. LSE is rich in polyphenols and has potent antioxidant capacity. APAP is a commonly used analgesic, while APAP overdose is the main reason for drug toxicity in the liver. Until now, there has been no in vitro test of LSE in drug-induced hepatotoxicity responses. LSEs were used to evaluate the effect on APAP-induced cytotoxicity, ROS level, apoptotic rate, and molecule mechanisms. The co-treatment of APAP and LSEs elevated the survival rate and decreased intracellular ROS levels on HepG2 cells. LSEs treatment could significantly reduce APAP-induced HepG2 apoptosis assessed by DAPI and Annexin V/PI. The further molecule mechanisms indicated that LSEs decreased Fas/FasL binding and reduced Bax and tBid to restore mitochondrial structure and subsequently suppress downstream apoptosis cascade activation. These declines in COX-2, NF-κB, and iNOS levels were observed in co-treatment APAP and LSEs, which indicated that LSEs could ameliorate APAP-induced inflammation. LSE protected APAP-induced apoptosis by preventing extrinsic, intrinsic, and JNK-mediated pathways. In addition, the restoration of mitochondria and inflammatory suppression in LSEs treatments indicated that LSEs could decrease oxidative stress induced by toxic APAP. Therefore, LSE could be a novel therapeutic option for an antidote against overdose of APAP.

Toxicological effects of acute prothioconazole and prothioconazole-desthio administration on liver in male Chinese lizards (Eremias argus)

Prothioconazole (PTC) is a high effective systemic fungicide, and one of its major metabolites is prothioconazole-desthio (PTC-d). Because of its wildly use in the farmland of China, the local eco-toxicological effects of PTC as well as PTC-d are needed to be concerned. This study investigated hepatoxicity of Chinese lizards (Eremias argus), a local non-target organism, after single dose oral treated (100 mg kg^-1 BW) through pathological, enzyme activity and gene expression analysis. PTC treatment caused ballooning and PTC-d treatment led to macrovesicular steatosis of hepatocyte. The elevation of serum indexes, including the activities of aspartate aminotransferase (AST), alkaline phosphatase (ALP) and alanine aminotransferase (ALT), further confirmed the hepatic injury. PTC and PTC-d treatments altered oxidative status reflected by the inhibition of superoxide dismutase (SOD) activity , meanwhile, the stimulation of catalase (CAT) activity, glutathione peroxidase (GPx) activity and malondialdehyde (MDA) content. The mRNA expression changes of apoptosis-related factors and cytokines genes, including Bax, Bcl-2, TNF-α, NF-κB, Caspase-3 and Nrf2, deeply uncovered the potential mechanism of hepatotoxicity caused by PTC and PTC-d. In brief, the results indicated that both of these two compounds altered oxidative status, then were likely to trigger caspase-3 by affecting the ratio of pro- and anti-apoptotic factors which belong to intrinsic apoptosis pathway. Specifically, more serious impacts were induced by PTC-d than its parent compound. This study is the first to provide specific insight into potential hepatotoxicity resulted from PTC and PTC-d in male Chinese lizards.

Excessive manganese alters serum biochemical indices, induces histopathological alterations, and activates apoptosis in liver and cerebrum of Jianzhou Da'er goat (Capra hircus)

The present study aimed to explore the toxic effects of excessive dietary Mn in livers and cerebrums of Jianzhou Da'er goat (Capra hircus). Three-month old goats were assigned into three groups: control group, fed on basal diet; Mn I group, fed on the basal diet mixed with MnCl₂ (2.5 g/kg); Mn II group, fed on the basal diet mixed with MnCl₂ (5 g/kg). Compared with the control group, the activities of serum alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and the concentrations of interferon-γ (IFN-γ) in Mn I and Mn II groups were significantly increased, but the concentrations of IgG in Mn I and Mn II groups were significantly decreased (p < 0.05). The activities of superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and the concentrations of glutathione (GSH) in Mn I and Mn II groups were significantly decreased, whereas the concentrations of malondialdehyde (MDA) in Mn I and Mn II groups were significantly increased in livers and cerebrums (p < 0.05). Moreover, the hepatocytes necrosed, inflammatory cells infiltrated, chromatin concentrated, mitochondrial cristae reduced in Mn I and Mn II groups. The nerve cells necrosed, blood vessels congested, inflammatory cells infiltrated, mitochondrial electron density and mitochondrial cristae decreased, and vacuolization increased in Mn I and Mn II groups. Furthermore, the mRNA expressions of tumor necrosis factor alpha (TNF-α), tumor necrosis factor receptor type 1 (TNFR1), fas-associated protein via a death domain (FADD), Bcl2-associated X (Bax), cysteinyl aspartate specific proteinase 3, 8, 9 (Caspase-3, 8, 9) in Mn I and Mn II groups were significantly increased (p < 0.05), but the mRNA expressions of B-cell lymphoma-2 (Bcl-2) in Mn I and Mn II groups were significantly decreased (p < 0.05) in livers. The mRNA expressions of Bcl-2, Bax, Caspase-3, 9, 7, 12 in Mn I and Mn II groups were significantly increased (p < 0.05), however, the ratio of Bcl-2/Bax in Mn I and Mn II groups was significantly decreased (p < 0.05) in cerebrums. In summary, our results provided new insights for better understanding the mechanisms of Mn toxicity in Capra hircus.

Bcl-3 promotes TNF-induced hepatocyte apoptosis by regulating the deubiquitination of RIP1

Tumor necrosis factor-α (TNF) is described as a main regulator of cell survival and apoptosis in multiple types of cells, including hepatocytes. Dysregulation in TNF-induced apoptosis is associated with many autoimmune diseases and various liver diseases. Here, we demonstrated a crucial role of Bcl-3, an IκB family member, in regulating TNF-induced hepatic cell death. Specifically, we found that the presence of Bcl-3 promoted TNF-induced cell death in the liver, while Bcl-3 deficiency protected mice against TNF/D-GalN induced hepatoxicity and lethality. Consistently, Bcl-3-depleted hepatic cells exhibited decreased sensitivity to TNF-induced apoptosis when stimulated with TNF/CHX. Mechanistically, the in vitro results showed that Bcl-3 interacted with the deubiquitinase CYLD to synergistically switch the ubiquitination status of RIP1 and facilitate the formation of death-inducing Complex II. This complex further resulted in activation of the caspase cascade to induce apoptosis. By revealing this novel role of Bcl-3 in regulating TNF-induced hepatic cell death, this study provides a potential therapeutic target for liver diseases caused by TNF-related apoptosis.

An anti-DR5 antibody-curcumin conjugate for the enhanced clearance of activated hepatic stellate cells

Anti-death receptor 5 (DR5) antibody is a potential therapeutic agent for liver fibrosis because it exhibits anti-fibrotic effects by inducing the apoptosis of activated hepatic stellate cells (HSCs), which are responsible for hepatic fibrogenesis. However, the clinical applications of anti-DR5 antibodies have been limited by their low agonistic activity against DR5. In this study, an anti-DR5 antibody-curcumin conjugate (DCC) was prepared to investigate its effect on the clearance of activated HSCs. The DCC was synthesized through a coupling reaction between a maleimide-functionalized curcumin derivative and a thiolated anti-DR5 antibody. No significant differences were observed in the uptake behaviors of activated HSCs between the bare anti-DR5 antibodies and DCC. Owing to the antioxidant and anti-inflammatory effects of curcumin, DCC-treated HSCs produced much lower levels of reactive oxygen species and inducible nitric oxide synthase than the bare anti-DR5 antibody-treated HSCs. Additionally, the anti-fibrotic effects of DCC on activated HSCs were more prominent than those of the bare anti-DR5 antibodies, as demonstrated by the immunocytochemical analysis of α-smooth muscle actin. DCC preferentially accumulated in the liver after its systemic administration to mice with liver fibrosis. Thus, DCC may serve as a potential therapeutic agent for treating liver fibrosis.

Inflammatory and Non-Inflammatory Mechanisms Controlling Cirrhosis Development

Simple Summary

The liver is continuously exposed to several harmful factors, subsequently activating sophisticated mechanisms set-up in order to repair and regenerate the damaged liver and hence to prevent its failure. When the injury becomes chronic, the regenerative response becomes perpetual and goes awry, leading to cirrhosis with a fatal liver dysfunction. Cirrhosis is a well-known risk factor for hepatocellular carcinoma (HCC), the most common, usually lethal, human primary liver neoplasm with very limited therapeutic options. Considering the pivotal role of immune factors in the development of cirrhosis, here we review and discuss the inflammatory pathways and components implicated in the development of cirrhosis. A better understanding of these circuits would help the design of novel strategies to prevent and treat cirrhosis and HCC, two lethal diseases.

Abstract

Because the liver is considered to be one of the most important metabolic organs in the body, it is continuously exposed to damaging environmental agents. Upon damage, several complex cellular and molecular mechanisms in charge of liver recovery and regeneration are activated to prevent the failure of the organ. When liver injury becomes chronic, the regenerative response goes awry and impairs the liver function, consequently leading to cirrhosis, a liver disorder that can cause patient death. Cirrhosis has a disrupted liver architecture and zonation, along with the presence of fibrosis and parenchymal nodules, known as regenerative nodules (RNs). Inflammatory cues contribute to the cirrhotic process in response to chronic damaging agents. Cirrhosis can progress to HCC, the most common and one of the most lethal liver cancers with unmet medical needs. Considering the essential role of inflammatory pathways in the development of cirrhosis, further understanding of the relationship between immune cells and the activation of RNs and fibrosis would guide the design of innovative therapeutic strategies to ameliorate the survival of cirrhotic and HCC patients. In this review, we will summarize the inflammatory mechanisms implicated in the development of cirrhosis.

Psiadin and plectranthone selectively inhibit colorectal carcinoma cells proliferation via modulating cyclins signaling and apoptotic pathways

Three scarce terpenes, psiadin, plectranthone and saudinolide, were obtained after chromatographic isolation and purification from the aerial parts of the respective plants. Their identities were established based on their spectral data. Their anticancer effects against two human colorectal carcinoma cell lines, CCL233 and CCL235, along with the potential molecular mechanisms of action, were explored. Psiadin and plectranthone exhibited marked growth inhibition on both cell lines in a time- and dose-dependent manner with minimal cytotoxicity against normal breast cells (HB2). The terpenes even showed superior activities to the tested standards. Flow cytometry showed apoptosis induction and alteration in the cell cycle in colorectal cancer cells treated with both compounds. Nevertheless, it was also found that both compounds inhibited NF-κB transcriptional activity, induced mitochondrial membrane potential depolarization and increased the percentage of reactive oxygen species in the treated cancer cells in a dose-dependent manner as well. Since the anticancer effect of psiadin on cancer cells was higher than that produced by plectranthone, only psiadin was tested to determine its possible targets. The results suggested a high degree of specificity of action affecting particular cellular processes in both cancer cells. In conclusion, both terpenes, in particular psiadin, showed significant discriminative therapeutic potential between cancer and normal cells, a value that is missing in current chemotherapies.

Lipid based nanocarriers for effective drug delivery and treatment of diabetes associated liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) is a cluster of several liver diseases like hepatic steatosis, non-alcoholic steatohepatitis (NASH), non-alcoholic fatty liver (NAFL), liver fibrosis, and cirrhosis which may eventually progress to liver carcinoma. One of the primary key factors associated with the development and pathogenesis of NAFLD is diabetes mellitus. The present review emphasizes on diabetes-associated development of liver fibrosis and its treatment using different lipid nanoparticles such as stable nucleic acid lipid nanoparticles, liposomes, solid lipid nanoparticles, nanostructured lipid carriers, self-nanoemulsifying drug delivery systems, and conjugates including phospholipid, fatty acid and steroid-based. We have comprehensively described the various pathological and molecular events linking effects of elevated free fatty acid levels, insulin resistance, and diabetes with the pathogenesis of liver fibrosis. Various passive and active targeting strategies explored for targeting hepatic stellate cells, a key target in liver fibrosis, have also been discussed in detail in this review.

Application of mesenchymal stem cell exosomes and their drug-loading systems in acute liver failure

Stem cell exosomes are nanoscale membrane vesicles released from stem cells of various origins that can regulate signal transduction pathways between liver cells, and their functions in intercellular communication have been recognized. Due to their natural substance transport properties and excellent biocompatibility, exosomes can also be used as drug carriers to release a variety of substances, which has great prospects in the treatment of critical and incurable diseases. Different types of stem cell exosomes have been used to study liver diseases. Due to current difficulties in the treatment of acute liver failure (ALF), this review will outline the potential of stem cell exosomes for ALF treatment. Specifically, we reviewed the pathogenesis of acute liver failure and the latest progress in the use of stem cell exosomes in the treatment of ALF, including the role of exosomes in inhibiting the ALF inflammatory response and regulating signal transduction pathways, the advantages of stem cell exosomes and their use as a drug‐loading system, and their pre‐clinical application in the treatment of ALF. Finally, the clinical research status of stem cell therapy for ALF and the current challenges of exosome clinical transformation are summarized.

FGF21: An Emerging Therapeutic Target for Non-Alcoholic Steatohepatitis and Related Metabolic Diseases

The rising global prevalence of obesity, metabolic syndrome, and type 2 diabetes has driven a sharp increase in non-alcoholic fatty liver disease (NAFLD), characterized by excessive fat accumulation in the liver. Approximately one-sixth of the NAFLD population progresses to non-alcoholic steatohepatitis (NASH) with liver inflammation, hepatocyte injury and cell death, liver fibrosis and cirrhosis. NASH is one of the leading causes of liver transplant, and an increasingly common cause of hepatocellular carcinoma (HCC), underscoring the need for intervention. The complex pathophysiology of NASH, and a predicted prevalence of 3-5% of the adult population worldwide, has prompted drug development programs aimed at multiple targets across all stages of the disease. Currently, there are no approved therapeutics. Liver-related morbidity and mortality are highest in more advanced fibrotic NASH, which has led to an early focus on anti-fibrotic approaches to prevent progression to cirrhosis and HCC. Due to limited clinical efficacy, anti-fibrotic approaches have been superseded by mechanisms that target the underlying driver of NASH pathogenesis, namely steatosis, which drives hepatocyte injury and downstream inflammation and fibrosis. Among this wave of therapeutic mechanisms targeting the underlying pathogenesis of NASH, the hormone fibroblast growth factor 21 (FGF21) holds considerable promise; it decreases liver fat and hepatocyte injury while suppressing inflammation and fibrosis across multiple preclinical studies. In this review, we summarize preclinical and clinical data from studies with FGF21 and FGF21 analogs, in the context of the pathophysiology of NASH and underlying metabolic diseases.

Expression profiling of key pathways in rat liver after a one-year feeding trial with transgenic maize MON810

In a recent one-year feeding study, we observed no adverse effects on tissue level in organs of rats fed with the genetically-modified maize MON810. Here, we assessed RNA expression levels of 86 key genes of the apoptosis-, NF-кB-, DNA-damage response (DDR)-, and unfolded-protein response (UPR) pathways by RT-qPCR in the rat liver. Male and female rats were fed either with 33% MON810 (GMO), isogenic- (ISO), or conventional maize (CONV) and RNAs were quantified from eight rats from each of the six feeding groups. Only Birc2 transcript showed a significant (p ≤ 0.05) consistent difference of ≥1.5-fold between the GMO and ISO groups in both sexes. Unsupervised cluster analysis showed a strong separation of male and female rats, but no clustering of the feeding groups. Individual analysis of the pathways did not show any clustering of the male or female feeding groups either, though transcript levels of UPR pathway-associated genes caused some clustering of the male GMO and CONV feeding group samples. These differences were not seen between the GMO and ISO control or within the female cohort. Our data therefore does not support an adverse effect on rat liver RNA expression through the long-term feeding of MON810 compared to isogenic control maize.

Serum cytokeratin-18 and its relation to liver fibrosis and steatosis diagnosed by FibroScan and controlled attenuation parameter in nonalcoholic fatty liver disease and hepatitis C virus patients

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most common cause of chronic liver disease worldwide. Multiple diagnostic noninvasive methods for NAFLD were studied (both serological and imaging), either single or combined. Attention has been focused on cytokeratin-18 (CK18) as a novel serological marker for the diagnosis of steatosis/fibrosis in NAFLD and hepatitis C virus (HCV) patients.

AIM

The aim of this study was to evaluate serum CK18 in NAFLD and HCV fibrosis/steatosis and also to correlate its performance with the diagnostic accuracy of transient elastography (TE) and controlled attenuation parameter (CAP) in the diagnosis of fibrosis/steatosis in these patients.

PATIENTS AND METHODS

Three equal groups of participants were enrolled (n=135): group I included patients with chronic HCV, group II included NAFLD patients, and group III included control participants. For all groups, TE/CAP and labs including serum CK18 were performed. Liver biopsy was performed for the NAFLD group.

RESULTS

Serum CK18 was significantly higher in the NAFLD group (19.01±3.49 ng/ml) versus the HCV group (8.95±1.06 ng/ml) and the control group (4.83±1.6 ng/ml) (P<0.001). The CK18 levels in biopsy stages (steatosis, ballooning, inflammation, and fibrosis) and FibroScan/CAP degrees showed that CK18 increased significantly with steatosis and fibrosis stages (biopsy or FibroScan/CAP), but did not reach significance with ballooning or inflammation grades. CK18 was significantly different in nonalcoholic steatohepatitis versus non-nonalcoholic steatohepatitis patients (P=0.041). The best CK18 cutoff to detect steatosis (S≥2) in NAFLD and HCV was 11.65 and 6.84 ng/ml, respectively with an overall sensitivity and specificity over 97%. The CK18 cutoff for significant fibrosis (F≥2) by FibroScan in the NAFLD/HCV groups was 9.115 ng/ml, with 62.5%/69.2% sensitivity/specificity (P=0.031). However, inflammation had a cutoff with a marginal P value (P=0.080), and a reliable cutoff for ballooning was not attained (P=0.386). There was a positive correlation between CK18 and fibrosis (by FibroScan) in the NAFLD and HCV groups (P<0.05). The correlation between CK18 and steatosis in CAP and the nonalcoholic fatty liver disease activity score was very good (P<0.001).

CONCLUSION

Serum CK18 is related strongly to the development/progression of NAFLD and HCV-related fibrosis/steatosis. TE was correlated highly with liver biopsy results. The combination of CK18 with other noninvasive modalities increases the diagnostic yield of these tests.

Modulations of Histone Deacetylase 2 Offer a Protective Effect through the Mitochondrial Apoptosis Pathway in Acute Liver Failure

The purpose of this study was to investigate the modulation of histone deacetylase 2 (HDAC2) on mitochondrial apoptosis in acute liver failure (ALF). The cellular model was established with LO2 cells stimulated by tumor necrosis factor alpha (TNF-α)/D-galactosamine (D-gal). Rats were administrated by lipopolysaccharide (LPS)/D-gal as animal model. The cell and animal models were then treated by HDAC2 inhibitor CAY10683. HDAC2 was regulated up or down by lentiviral vector transfection in LO2 cells. The mRNA levels of bcl2 and bax were detected by real-time PCR. The protein levels of HDAC2, bcl2, bax, cytochrome c (cyt c) in mitochondrion and cytosol, apoptosis protease activating factor 1 (apaf1), caspase 3, cleaved-caspase 3, caspase 9, cleaved-caspase 9, acetylated histone H3 (AH3), and histone H3 (H3) were assayed by western blot. Apoptosis was detected by flow cytometry. The serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBIL) levels were also assayed. The openness degree of the mitochondrial permeability transition pore (MPTP) was detected by ultraviolet spectrophotometry. The apoptosis of hepatocytes in liver tissues was determined by tunnel staining. The liver tissue pathology was detected by hematoxylin eosin (HE) staining. The ultrastructure of liver tissue was observed by electron microscopy. Compared with cell and rat model groups, the bax mRNA level was decreased, and bcl2 mRNA was increased in the CAY10683 treatment group. The protein levels of HDAC2, bax, cyt c in cytosol, apaf1, cleaved-caspase 3, and cleaved-caspase 9 were decreased, and the apoptosis rate was decreased (P < 0.05), whereas the protein level of bcl2 and cyt c in the mitochondrion was elevated (P < 0.05) in the CAY10683 treatment group. In the HDAC2 down- or upregulated LO2 cells, the mitochondrial apoptosis pathway was inhibited or activated, respectively. After being treated with TNF-α/D-gal in HDAC2 down- or upregulated LO2 cells, the mitochondrial apoptosis pathway was further suppressed or activated, respectively. The MPTP value was elevated in CAY10683-treated groups compared with the rat model group (P < 0.05). Liver tissue pathological damage and apoptotic index in the CAY10683-treated group were significantly reduced. In addition, AH3 was elevated in both cell and animal model groups (P < 0.05). Downregulated or overexpressed HDAC2 could accordingly increase or decrease the AH3 level, and TNF-α/D-gal could enhance the acetylation effect. These results suggested that modulations of histone deacetylase 2 offer a protective effect through the mitochondrial apoptosis pathway in acute liver failure.

Chemically modified liposomes carrying TRAIL target activated hepatic stellate cells and ameliorate hepatic fibrosis in vitro and in vivo

At present, no satisfactory anti-liver fibrosis drugs have been used clinically due to the poor targeting ability and short half-life period. This study aimed to explore the effects of a new TRAIL (TNF-related apoptosis-inducing ligand) preparation that can target aHSCs (activated hepatic stellate cells) on liver fibrosis and explain the possible underlying mechanism. Using our self-made drug carrier pPB-SSL that specifically targets aHSCs, recombinant human TRAIL (rhTRAIL) protein was embedded in (named as pPB-SSL-TRAIL) and applied to treat liver fibrotic mice as well as 3T3 fibroblast cells and aHSCs. Through in vitro and in vivo experiments, we found that, compared with the groups treated with TRAIL (free rhTRAIL) and SSL-TRAIL (rhTRAIL capsulated within unmodified liposome), the group treated with pPB-SSL-TRAIL nanoparticles showed significantly lower cell viability and higher cell apoptosis in vitro. The targeting delivering system pPB-SSL also significantly enhanced the anti-fibrotic effect, apoptosis induction and long circulation of rhTRAIL. After the treatment with pPB-SSL-TRAIL, apoptosis of aHSCs was notably increased and hepatic fibrosis in mice was remarkably alleviated. In vitro, pPB-SSL-TRAIL nanoparticles were mainly transported and located on membrane or into cytoplasm, but the particles were distributed mainly in mouse fibrotic liver and most on the cell membrane of aHSCs. In conclusion, rhTRAIL carried by pPB-SSL delivering system has prolonged circulation in blood, be able to target aHSCs specifically, and alleviate fibrosis both in vitro and in vivo. It presents promising prospect in the therapy of liver fibrosis, and it is worthwhile for us to develop it for clinical use.

Randomised clinical trial: emricasan versus placebo significantly decreases ALT and caspase 3/7 activation in subjects with non-alcoholic fatty liver disease

BACKGROUND

Lipotoxicity leading to excessive caspase-mediated apoptosis and inflammation is believed to drive liver damage in NAFLD. Emricasan is a pan-caspase inhibitor that decreased serum ALT and apoptotic and inflammatory markers in subjects with chronic hepatitis.

AIMS

To assess whether 28 days of emricasan would reduce elevated levels of serum ALT, AST, cleaved cytokeratin-18, full-length cytokeratin-18, and caspase 3/7 in subjects with NAFLD and raised aminotransferases.

METHODS

Double-blind, placebo-controlled, office-practice study assessed the efficacy, safety, and tolerability of emricasan in subjects with NAFLD and ALT levels ≥1.5 x ULN during screening. Subjects were randomised to emricasan 25 mg twice daily or matching placebo. Subjects with cirrhosis and other causes for raised aminotransferases were excluded. The primary endpoint was the change in ALT at day 28 in the emricasan group vs placebo.

RESULTS

38 subjects were randomised, 19 each to emricasan or placebo. Baseline disease factors were well balanced except for lower median ALT values in emricasan subjects. Three subjects randomised to placebo discontinued prior to day 28. ALT values decreased significantly in emricasan-treated subjects vs placebo at days 7 (P < 0.0001) and 28 (P = 0.02). cCK18 (day 7), flCK18 (days 7 and 28), and caspase 3/7 (day 7) were also significantly decreased in emricasan-treated subjects vs placebo. Emricasan treatment was generally safe and well tolerated.

CONCLUSIONS

Emricasan decreased ALT and biomarkers in subjects with NAFLD and raised aminotransferases after 28 days. These results support the further development of emricasan in patients with NAFLD.

TRIAL REGISTRATION

ClinicalTrials.gov, Identifier: NCT02077374.

Beraprost sodium preconditioning prevents inflammation, apoptosis, and autophagy during hepatic ischemia-reperfusion injury in mice via the P38 and JNK pathways

OBJECTIVE

The goal of this study was to determine the effects of beraprost sodium (BPS) preconditioning on hepatic ischemia-reperfusion (IR) injury and its underlying mechanisms of action.

MATERIALS AND METHODS

Mice were randomly divided into sham, IR, IR+BPS (50 µg/kg), and IR+BPS (100 µg/kg) groups. Saline or BPS was given to the mice by daily gavage for 1 week before the hepatic IR model was established. Liver tissues and orbital blood were collected at 2, 8, and 24 hours after reperfusion for the determination of liver enzymes, inflammatory mediators, apoptosis- and autophagy-related proteins, key proteins in P38 and c-Jun N-terminal kinase (JNK) cascades, and evaluation of liver histopathology.

RESULTS

BPS preconditioning effectively reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, improved pathological damage, ameliorated production of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), and affected expressions of Bax, Bcl-2, Caspase-3, Caspase-8, and Caspase-9, microtubule-associated protein 1 light chain 3 (LC3), Beclin-1, and P62. The protective effects of BPS preconditioning were associated with reduced P38 and JNK phosphorylation.

CONCLUSION

BPS preconditioning ameliorated hepatic IR injury by suppressing inflammation, apoptosis, and autophagy, partially via inhibiting activation of the P38 and JNK cascades.

Future Pharmacotherapy for Non-alcoholic Steatohepatitis (NASH): Review of Phase 2 and 3 Trials

Non-alcoholic steatohepatitis (NASH) results from inflammation and hepatocyte injury in the setting of hepatic steatosis. Non-alcoholic steatohepatitis increases the risk of progression to liver fibrosis and cirrhosis, and is the most rapidly growing etiology for liver failure and indication for liver transplantation in the USA. Weight loss and lifestyle modification remain the standard first-line treatment, as no USA Food and Drug Administration-approved pharmacotherapy currently exists. The past decade has seen an explosion of interest in drug development targeting pathologic pathways in non-alcoholic steatohepatitis, with numerous phase 2 and 3 trials currently in progress. Here, we concisely review the major targets and mechanisms of action by class, summarize results from completed pivotal phase 2 studies, and provide a detailed outline of key active studies with trial data for drugs in development, including obeticholic acid, elafibranor, cenicriviroc and selonsertib.

Protective role of curcumin in ameliorating AFB1-induced apoptosis via mitochondrial pathway in liver cells

It is well documented that liver is the primary target organ of aflatoxin B₁ (AFB₁) and curcumin proved to be effective against AFB₁-induced liver injury. In the present study, we investigated the preventive effects of curcumin against AFB₁-induced apoptosis through the molecular regulation of p53, caspase-3, Bax, caspase-9, Bcl-2 and cytochrome-C associated with mitochondrial pathway. Liver antioxidant levels were measured. The hallmarks of apoptosis were analysed by methyl green-pyronin-Y staining, transmission electron microscopy, RT-PCR and western blot. Results revealed that dietary curcumin ameliorated AFB₁-induced oxidative stress in a dose-dependent manner. Methyl green-pyronin-Y staining and transmission electron microscopy showed that AFB₁ induced apoptosis and caused abnormal changes in liver cells morphology such as condensation of chromatin material, reduces cell volume and damaged mitochondria. Moreover, mRNA and protein expression results manifested that apoptosis associated genes showed up-regulation in AFB₁ fed group. However, the supplementation of dietary curcumin (dose-dependently) alleviated the increased expression of the apoptosis associated genes at mRNA and protein level, and restored the hepatocytes normal morphology. The study provides an insight and a better understanding of the preventive mechanism of curcumin against AFB₁-induced apoptosis in hepatocytes and provide scientific basis for the therapeutic uses of curcumin.

Aflatoxin B1 invokes apoptosis via death receptor pathway in hepatocytes

The fungal metabolites produced by Aspergillus flavus and Aspergillus parasiticus cause detrimental health effects on humans and animals. Particularly aflatoxin B1 (AFB1) is the most studied and a well-known global carcinogen, producing hepatotoxic, genotoxic and immunotoxic effects in multiple species. AFB1 is shown to provoke liver dysfunctioning by causing hepatocytes apoptosis and disturbing cellular enzymatic activities. In liver, AFB1 causes apoptosis via extrinsic mechanism because of high expression of death receptor pathway. The detailed mechanism of AFB1 induced hepatocytes apoptosis, via death receptor pathway still remains elusive. So the present study was conducted to explore apoptotic mechanism initiated by death receptors and associated genes in aflatoxin B1 induced liver apoptosis in chickens fed with AFB1 for 3 weeks. Results from the present study displayed histopathological and ultrastructural changes in liver such as hydropic degeneration, fatty vacuolar degeneration and proliferation of bile duct in hepatocytes in AFB1 group, along with imbalance between reactive oxygen species (ROS) and antioxidant defense system upon AFB1 ingestion. Moreover, AFB1 intoxicated chickens showed upregulation of death receptors FAS, TNFR1 and associated genes and downregulation of inhibitory apoptotic proteins XIAP and BCL-2. The results obtained from this novel and comprehensive study including histopathological, ultrastructural, flow cytometrical and death receptor pathway gene expression profiles, will facilitate better understanding of mechanisms and involvement of death receptor pathway in hepatocytes apoptosis induced by AFB1 and ultimately may be helpful in bringing down the toxigenic potential of AFB1.

The Receptor Interacting Protein Kinases in the Liver

The receptor interacting serine/threonine kinase1 and 3 (RIPK1, RIPK3) are regulators of cell death and survival. RIPK1 kinase activity is required for necroptosis and apoptosis, while its scaffolding function is necessary for survival. Although both proteins can mediate apoptosis, RIPK1 and RIPK3 are most well-known for their role in the execution of necroptosis via the mixed lineage domain like pseudokinase. Necroptosis is a caspase-independent regulated cell death program which was first described in cultured cells with unknown physiologic relevance in the liver. Many recent reports have suggested that RIPK1 and/or RIPK3 participate in liver disease pathogenesis and cell death. Notably, both proteins have been shown to mediate inflammation independent of cell death. Whether necroptosis occurs in hepatocytes, and how it is executed in the presence of an intact caspase machinery is controversial. In spite of this controversy, it is evident that RIPK1 and RIPK3 participate in many experimental liver disease models. Therefore, in addition to cell death signaling, their necroptosis-independent role warrants further examination.

Neutralization of CD95 ligand protects the liver against ischemia-reperfusion injury and prevents acute liver failure

Ischemia-reperfusion injury is a common pathological process in liver surgery and transplantation, and has considerable impact on the patient outcome and survival. Death receptors are important mediators of ischemia-reperfusion injury, notably the signaling pathways of the death receptor CD95 (Apo-1/Fas) and its corresponding ligand CD95L. This study investigates, for the first time, whether the inhibition of CD95L protects the liver against ischemia-reperfusion injury. Warm ischemia was induced in the median and left liver lobes of C57BL/6 mice for 45 min. CD95Fc, a specific inhibitor of CD95L, was applied prior to ischemia. Hepatic injury was assessed via consecutive measurements of liver serum enzymes, histopathological assessment of apoptosis and necrosis and caspase assays at 3, 6, 12, 18 and 24 h after reperfusion. Serum levels of liver enzymes, as well as characteristic histopathological changes and caspase assays indicated pronounced features of apoptotic and necrotic liver damage 12 and 24 h after ischemia-reperfusion injury. Animals treated with the CD95L-blocker CD95Fc, exhibited a significant reduction in the level of serum liver enzymes and showed both decreased histopathological signs of parenchymal damage and decreased caspase activation. This study demonstrates that inhibition of CD95L with the CD95L-blocker CD95Fc, is effective in protecting mice from liver failure due to ischemia-reperfusion injury of the liver. CD95Fc could therefore emerge as a new pharmacological therapy for liver resection, transplantation surgery and acute liver failure.

Pre-clinical study of a TNFR1-targeted 18F probe for PET imaging of breast cancer

Tumor necrosis factor receptor 1 (TNFR1) is overexpressed in several varieties of carcinoma, including breast cancer. WH701 (Ala-Thr-Ala-Gln-Ser-Ala-Tyr-Gly), which was identified by phage display, can specifically bind to TNFR1. In this study, we labeled WH701 with ¹⁸F and investigated its tumor diagnostic value. WH701 was synthesized by standard Fmoc-solid phase synthetic protocols and conjugated by NOTA-NHS. NOTA-WH701 was radiolabeled with ¹⁸F using NOTA-AlF chelation reaction. The tumor target properties were evaluated in vitro and in vivo using MCF-7 xenografts and inflammation models. [¹⁸F]AlF-NOTA-WH701 was labeled in 25 min with a decay-corrected yield of 38.1 ± 4.8% (n = 5) and a specific activity of 10.4-13.0 GBq/μmol. WH701 had relatively high affinity for MCF-7 cells in vitro and [¹⁸F]AlF-NOTA-WH701 displayed relatively high tumor uptake in vivo. The tumor to muscle ratio was 4.25 ± 0.56 at 30 min post-injection (p.i.); further, there was a significant difference between the tumor/muscle and inflammation/muscle (3.22 ± 0.56) ratio, which could differentiate the tumor and inflammation. The tumor uptake of [¹⁸F]AlF-NOTA-WH701 could be inhibited by 71.1% by unlabeled WH701 at 30 min p.i. We have developed a promising PET tracer [¹⁸F]AlF-NOTA-WH701 for the noninvasive detection of breast cancer in vivo.

Virus Infection and Death Receptor-Mediated Apoptosis

Virus infection can trigger extrinsic apoptosis. Cell-surface death receptors of the tumor necrosis factor family mediate this process. They either assist persistent viral infection or elicit the elimination of infected cells by the host. Death receptor-mediated apoptosis plays an important role in viral pathogenesis and the host antiviral response. Many viruses have acquired the capability to subvert death receptor-mediated apoptosis and evade the host immune response, mainly by virally encoded gene products that suppress death receptor-mediated apoptosis. In this review, we summarize the current information on virus infection and death receptor-mediated apoptosis, particularly focusing on the viral proteins that modulate death receptor-mediated apoptosis.

The Path to Cancer and Back: Immune Modulation During Hepatitis C Virus Infection, Progression to Fibrosis and Cancer, and Unexpected Roles of New Antivirals

Hepatitis C virus (HCV) infection affects over 130 million individuals worldwide, and it is the number 1 reason for liver transplantation in the United States. HCV infection progresses in a slow chronic fashion eliciting a strong but ineffective immune response, mainly characterized by NK cell dysfunction and T cell exhaustion. The chronic hepatic inflammation leads to liver fibrosis, cirrhosis, and cancer in a significant number of patients. In recent years, groundbreaking research has led to the discovery of new HCV-specific direct-acting antivirals (DAAs), which have an unprecedented efficacy to clear the virus, and establish a sustained virological response. Indeed, curing HCV infection with an oral medication is now reality. The effects of DAAs in mitigating the HCV-related complications of liver fibrosis and cancer are yet largely unknown. Nonetheless, recent controversial reports suggest a potential increase in liver cancer recurrence upon use of DAAs. In the current article, we review the most important immune-mediated mechanisms underlying HCV chronicity and the development of liver fibrosis and cancer. Furthermore, we discuss recent concern on use of the new agents.

Serum levels of caspase-cleaved cytokeratin 18 (CK18-Asp396) predict severity of liver disease in chronic hepatitis B

Background and aim

Caspase-cleaved cytokeratin 18 (CK18-Asp396) is a potential clinically useful biomarker in liver disease as it is released from hepatocytes during apoptosis. In this study, we investigated serum CK18-Asp396 levels in chronic hepatitis B (CHB).

Patients and methods

Overall, 163 patients with CHB were included. Serum CK18-Asp396 levels were determined by enzyme-linked immunosorbent assay (ELISA), and results were related to steatosis grade, histological activity index, inflammation score, and METAVIR fibrosis grade as well as to viral load, serum levels of liver enzymes, and albumin. Receiver operating characteristic analysis was used to evaluate the diagnostic performance of serum CK18-Asp396 levels for assessing disease activity.

Results

A higher level of serum CK 18 concentrations was found in patients with significant inflammation vs no significant inflammation (378.5 [interquartile range {IQR}: 173.2–629.6] vs 137.3 [87.5–197.7], P < 0.05; approximately threefold increase) and in patients with significant fibrosis vs no significant fibrosis (177.8 [IQR: 120.8–519.1] vs 142.7 [IQR: 88.8–214.4], P < 0.05; 1.25-fold increase). There was no differential CK 18 level by degree of steatosis. CK 18 was an independent predictor of significant inflammation with an 82% specificity and a 94% negative predictive value. We found the strongest correlation of CK 18 with alanine aminotransferase and aspartate aminotransferase (both r = 0.52; P < 0.001), but less with albumin (r = −0.24; P < 0.05) and viral load (log) (r = 0.19; P < 0.05).

Conclusion

CHB appears to be accompanied by continuous high levels of hepatocyte apoptosis as judged from serum CK 18, suggesting that elimination of the infected compartment constitutes a defensive strategy against disease. Accordingly, CK 18 works as an independent predictor of significant inflammation with a high specificity.

Hepatoprotective Effect of Gallotannin-enriched Extract Isolated from Gall on Hydrogen Peroxide-induced Cytotoxicity in HepG2 Cells

Background:

Gall (Galla Rhois [GR]) is known to have antibacterial, anti-inflammatory, antimetastatic, and anti-invasion activities and exert hepatoprotective effects. However, the hepatoprotective effects of gallotannin-enriched GR (GEGR) and their mechanisms have not yet been investigated.

Objective:

The potential protective effect of GEGR against hepatotoxicity induced by hydrogen peroxide (H₂O₂) was investigated.

Materials and Methods:

Changes in cell viability, apoptosis protein expression, and reactive oxygen species (ROS) generation were determined in HepG2 cells that were pretreated with four different concentrations of GEGR (6.25–50 μg/ml) for 24 h before H₂O₂ exposure.

Results:

GEGR consisted of gallotannin (69.2%), gallic acid (26.6%), and methyl gallate (4.2%) and showed remarkable 2,2-diphenyl-1-picrylhydrazyl scavenging activity (inhibitory concentration 50% = 0.212 μg/ml). The lethal dose 50% and effective dose 50% values for the response of HepG2 cells to GEGR were determined to be 178 and 6.85 μg/ml, respectively. Significant reductions in the immunofluorescence intensity indicating apoptosis were also detected in the nuclei of HepG2 cells stained with 4’,6-diamidino-2-phenylindole and Annexin V after GEGR treatment. The Bax/Bcl-2 ratio and active caspase-3 level were higher in H₂O₂ + vehicle-treated cells. However, these levels gradually decreased to those of the No-treated group in the GEGR pretreated group even though little or no decrease was observed in response to low GEGR concentrations. Furthermore, the GEGR pretreated group showed a reduced level of 2’,7’-dichlorofluorescein diacetate stained cells, indicating ROS generation relative to the H₂O₂ + vehicle-treated group.

Conclusion:

The results of this study provide strong evidence that GEGR can prevent cell death induced by H₂O₂ in HepG2 cells through the induction of antioxidant conditions.

SUMMARY

The gallotannin (69.2%), gallic acid (26.6%), and methyl gallate (4.2%) are the main constituents of water extracts of GR

GEGR was more potent in DPPH scavenging, and gallotannin contributes to this extract activity

GEGR significantly reduced the increase of apoptosis, Bax/Bcl-2 ratio, and active caspase-3 level after H2O2 treatment

GEGR pretreatment showed protection against H₂O₂-induced ROS production in DCFH-DA staining analysis.

Abbreviations used: COX: Cyclooxygenase; DAPI: 4’,6-diamidino-2-phenylindole; DMSO: Dimethyl sulfoxide; DPPH: 2,2-diphenyl-1-picrylhydrazyl; GEGR: Gallotannin-enriched Galla Rhois; GR: Galla Rhois; HPLC: High-performance liquid chromatography; H₂O₂: Hydrogen peroxide; MMP: Metallopeptidase; MTT: 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide; ROS: Reactive oxygen species; UV-Vis: Ultraviolet-visible.

Hypothermic Maintenance of Hepatocyte Spheroids

Primary hepatocytes form spheroids under some culture conditions. These spheroids exhibit many tissuelike ultrastructures and retain many liver-specific functions over a long period of time. They are attractive for many applications employing liver cells. The ability to maintain their viability and functions at a reduced temperature to allow for transportation to the site of their application will facilitate their use. Furthermore, with their structural and functional similarity, they could possibly be used as a model system for studying various liver ischemias. The effect of hypothermic treatment was assessed by oxygen consumption rate, ATP, H2O2, and caspase 8 content, as well as albumin and urea synthesis, during and posttreatment. No single outcome variable gives a superlative quantification of hypothermic damage. Taken together, the hypothermic treatment can be seen as increasingly damaging as the temperature decreases from 21°C to 15°C and 4°C. The addition of the chemical protectants glutathione, N-acetyl-L-cystein (NAC), and tauroursodeoxycholic acid (TUDCA) decreased the damaging effect of hypothermic treatment. This protection effect was even more profound when spheroids were preincubated with the protectant for 24 h, and was most prominent at 4°C. The viability of the hypothermically treated hepatocyte spheroids was confirmed by laser scanning confocal microscopy. The method reported provides a means of maintaining spheroids' viability and may allow for their distribution to application sites at a distance.

Caspase 3 role and immunohistochemical expression in assessment of apoptosis as a feature of H1N1 vaccine-caused Drug-Induced Liver Injury (DILI)

Background

Drug-Induced Liver Injury (DILI) changes, occur post exposure to natural or chemical compounds including apoptosis.

Aim

To assess the H1N1 vaccine-caused DILI by histochemical and immunohistochemical methods.

Methods

This 2014’s experimental study was conducted on 70 albino rats. They were given Arepanrix^TM H1N1 vaccine and were divided into 7 groups; 10 mice each, as control (non-vaccinated), vac2 and vac4 injected with 1^st and 2^nd doses of vaccine (suspension only) and euthanized after 3 weeks each, vac5 euthanized 6 weeks after 2^nd dose, mix2 and mix4 injected with 1^st and 2^nd doses of vaccine (mixture of suspension and adjuvant) and euthanized after 3 weeks each, mix5 and euthanized 6 weeks after 2^nd dose. Histopathological evaluation and histochemical assessment of metabolic protein, glycogen and collagen changes using PAS, bromophenol blue, Mallory’s trichrome and immunohistochemistry for caspase 3 on liver tissue paraffin sections were done. Image analysis system Leica QIIN 500 was used. Data were analyzed by SPSS software, using descriptive statistics and ANOVA.

Results

Histopathological changes ranging from subtle up to necrosis were noticed, mainly in mix groups. Metabolic protein and glycogen changes were the maximum in mix5 group (p<0.01). Collagen deposition in sinusoids was higher in mix groups, and maximally in vac5 and mix5. Apoptotic hepatocytes expressing diffuse strong nuclear and cytoplasmic caspase 3 were the highest in mix5.

Conclusion

H1N1 vaccine can cause DILI by either direct toxic or idiosyncratic metabolic type reactions rather than immunologic hypersensitivity type. It ranges from subtle changes up to necrosis. Caspase 3 is pivotal in liver damage etiology, apoptosis induction and processing. Follow up for at least 2 months after the 2^nd dose of H1N1 vaccine is recommended to rule out H1N1-induced DILI.

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.

ATP11C targets basolateral bile salt transporter proteins in mouse central hepatocytes

ATP11C is a homolog of ATP8B1, both of which catalyze the transport of phospholipids in biological membranes. Mutations in ATP8B1 cause progressive familial intrahepatic cholestasis type1 in humans, which is characterized by a canalicular cholestasis. Mice deficient in ATP11C are characterized by a conjugated hyperbilirubinemia and an unconjugated hypercholanemia. Here, we have studied the hypothesis that ATP11C deficiency interferes with basolateral uptake of unconjugated bile salts, a process mediated by organic anion-transporting polypeptide (OATP) 1B2. ATP11C localized to the basolateral membrane of central hepatocytes in the liver lobule of control mice. In ATP11C-deficient mice, plasma total bilirubin levels were 6-fold increased, compared to control, of which ∼65% was conjugated and ∼35% unconjugated. Plasma total bile salts were 10-fold increased and were mostly present as unconjugated species. Functional studies in ATP11C-deficient mice indicated that hepatic uptake of unconjugated bile salts was strongly impaired whereas uptake of conjugated bile salts was unaffected. Western blotting and immunofluorescence analysis demonstrated near absence of basolateral bile salt uptake transporters OATP1B2, OATP1A1, OATP1A4, and Na(+) -taurocholate-cotransporting polypeptide only in central hepatocytes of ATP11C-deficient liver. In vivo application of the proteasome inhibitor, bortezomib, partially restored expression of these proteins, but not their localization. Furthermore, we observed post-translational down-regulation of ATP11C protein in livers from cholestatic mice, which coincided with reduced OATP1B2 levels.

CONCLUSIONS

ATP11C is essential for basolateral membrane localization of multiple bile salt transport proteins in central hepatocytes and may act as a gatekeeper to prevent hepatic bile salt overload. Conjugated hyperbilirubinemia and unconjugated hypercholanemia and loss of OATP expression in ATP11C-deficient liver strongly resemble the characteristics of Rotor syndrome, suggesting that mutations in ATP11C can predispose to Rotor syndrome. (Hepatology 2016;64:161-174).

Hydrogen-rich saline protects against mitochondrial dysfunction and apoptosis in mice with obstructive jaundice

Previous studies have demonstrated that hydrogen-rich saline (HS) protects against bile duct ligation (BDL)-induced liver injury by suppressing oxidative stress and inflammation. Mitochondria, which are targets of excessive reactive oxygen species and central mediators of apoptosis, have a pivotal role in hepatic injury during obstructive jaundice (OJ); however, the implications of HS in the hepatic mitochondria of BDL mice remain unknown. The present study investigated the hypothesis that HS could reduce OJ‑induced liver injury through the protection of mitochondrial structure and function, as well as inhibition of the mitochondrial apoptotic pathway. Male C57BL/6 mice were randomly divided into three experimental groups: Sham operation group, BDL injury with normal saline (NS) treatment group, and BDL‑injury with HS treatment group. Mitochondrial damage and apoptotic parameters were determined 3 days post‑BDL injury and treatment. The results demonstrated that mitochondria isolated from the livers of NS-treated BDL mice exhibited increased mitochondrial swelling, cytochrome c release, and oxidative damage. In addition, liver samples from NS‑treated BDL mice exhibited significant increases in B‑cell lymphoma 2 (Bcl‑2)‑associated X protein expression, caspase activities, and hepatocyte apoptosis compared with livers from sham‑operated controls. Notably, treatment with HS reduced the levels of these markers and alleviated morphological defects in the mitochondria following injury. In addition, HS markedly increased the antioxidant potential of mitochondria, as evidenced by elevated adenosine triphosphate levels, mitochondrial respiratory function, and increased levels of active Bcl‑2. In conclusion, HS attenuates mitochondrial oxidative stress and dysfunction, and inhibits mitochondrial-mediated apoptosis in the livers of BDL mice.

Cytokeratin 18-Aspartate396 apoptotic fragment for fibrosis detection in patients with non-alcoholic fatty liver disease and chronic viral hepatitis

BACKGROUND

The combination of non-invasive markers for the detection of fibrosis in patients with chronic liver diseases is still a matter of debate.

AIMS

To test the performance of cytokeratin18-Aspartate396 alone or in combination with transient elastography as a marker of fibrosis, compared to liver biopsy as gold standard.

METHODS

In 259 prospectively enrolled patients with chronic liver diseases, clinical, biochemical, and histological features were assessed. Serum cytokeratin18-Aspartate396 and Fibroscan were performed within 6 months prior to liver biopsy.

RESULTS

Cytokeratin18-Aspartate396 levels predicted both significant and advanced fibrosis in non-alcoholic fatty liver disease group, correctly identifying 83.7% and 80.8% of cases, respectively. Liver stiffness performed best in predicting severe fibrosis in patients with chronic viral infection, correctly identifying 78.7% of chronic hepatitis B and 88.6% of chronic hepatitis C subjects. The combination of cytokeratin18-Aspartate396 and liver stiffness improved their diagnostic performance for the detection of significant and advanced fibrosis in non-alcoholic fatty liver disease group, only (sensitivity=78.3%, specificity=90.7%; sensitivity=91.7%, specificity=71.6%, respectively).

CONCLUSION

Cytokeratin18-Aspartate396 and liver stiffness can improve the non-invasive prediction of significant and advanced fibrosis in patients with non-alcoholic fatty liver disease, while in hepatitis B and C virus infected patients their combined use had no advantage over the diagnostic accuracy of transient elastography alone.

Interferon-Mediated Cytokine Induction Determines Sustained Virus Control in Chronic Hepatitis C Virus Infection

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease and associated complications such as liver cirrhosis and hepatocellular carcinoma. Interferons (IFNs) are crucial for HCV clearance and a sustained virological response (SVR), but a significant proportion of patients do not respond to IFNα. The underlying mechanisms of an insufficient IFN response remain largely unknown. In this study, we found that patients responding to IFNα with viral clearance had significantly higher serum levels of TNF-related apoptosis inducing ligand (TRAIL), compared with patients who failed to control HCV. In addition, upon direct IFNα exposure, peripheral blood mononuclear cells (PBMCs) from patients with SVR upregulated TRAIL, as well as IFN-γ and the chemokines CXCL9 and CXCL10, much more strongly than cells from patients with antiviral treatment failure. As a possible mechanism of the stronger IFNα-induced cytokine response, we identified higher levels of expression and phosphorylation of the transcription factor STAT1 in PBMCs from patients with SVR. Increased TRAIL expression additionally involved the NF-κB and JNK signaling pathways. Thus, SVR in chronic HCV infection is associated with a strong IFNα-induced cytokine response, which might allow for the early prediction of treatment efficacy in HCV infection.

Xenobiotic and Endobiotic Mediated Interactions Between the Cytochrome P450 System and the Inflammatory Response in the Liver

The liver is a unique organ in the body as it has significant roles in both metabolism and innate immune clearance. Hepatocytes in the liver carry a nearly complete complement of drug metabolizing enzymes, including numerous cytochrome P450s. While a majority of these enzymes effectively detoxify xenobiotics, or metabolize endobiotics, a subportion of these reactions result in accumulation of metabolites that can cause either direct liver injury or indirect liver injury through activation of inflammation. The liver also contains multiple populations of innate immune cells including the resident macrophages (Kupffer cells), a relatively large number of natural killer cells, and blood-derived neutrophils. While these cells are primarily responsible for clearance of pathogens, activation of these immune cells can result in significant tissue injury during periods of inflammation. When activated chronically, these inflammatory bouts can lead to fibrosis, cirrhosis, cancer, or death. This chapter will focus on interactions between how the liver processes xenobiotic and endobiotic compounds through the cytochrome P450 system, and how these processes can result in a response from the innate immune cells of the liver. A number of different clinically relevant diseases, as well as experimental models, are currently available to study mechanisms related to the interplay of innate immunity and cytochrome P450-mediated metabolism. A major focus of the chapter will be to evaluate currently understood mechanisms in the context of these diseases, as a way of outlining mechanisms that dictate the interactions between the P450 system and innate immunity.

Growth inhibitory and chemo-sensitization effects of naringenin, a natural flavanone purified from Thymus vulgaris, on human breast and colorectal cancer

BACKGROUND

Natural products with diverse bioactivities are becoming an important source of novel agents with medicinal potential. Cancer is a devastating disease that causes the death of millions of people each year. Thus, intense research has been conducted on several natural products to develop novel anticancer drugs.

METHODS

Chromatographic and spectral techniques were used for the isolation and identification of naringenin (Nar). MTT, flow cytometry, western blotting, Real Time PCR were used to test anticancer and chemosensitizing effects of Nar, cell cycle, apoptosis, and expression of cell cycle, apoptosis, pro-survival and anti-survival-related genes.

RESULTS

In the present study, Thymus vulgaris ethanol extract was purified repeatedly to produce several compounds including the known flavanone, Nar which was identified using different spectral techniques. Nar was shown to inhibit both human colorectal and breast cancer cell growth in a dose- and time-dependent manner through cell cycle arrest at S- and G2/M-phases accompanied by an increase in apoptotic cell death. Additionally, Nar altered the expression of apoptosis and cell-cycle regulatory genes by down-regulating Cdk4, Cdk6, Cdk7, Bcl2, x-IAP and c-IAP-2 and up-regulating p18, p19, p21, caspases 3, 7, 8 and 9, Bak, AIF and Bax in both colorectal and breast cancer cells. Conversely, it diminished the expression levels of the cell survival factors PI3K, pAkt, pIκBα and NFκBp65. Moreover, Nar enhanced the sensitivity of colorectal and breast cancer cells to DNA-acting drugs.

DISCUSSION

These findings provide evidence that Nar's pro-apoptotic and chemo-sensitizing effects are mediated by perturbation of cell cycle, upregulation of pro-apoptotic genes and down-regulation of anti-apoptotic genes and inhibition of pro-survival signaling pathways.

CONCLUSION

In conclusion, Nar might be a promising candidate for chemoprevention and/or chemotherapy of human cancers. However, further studies exploring this therapeutic strategy are necessary.

Anti-apoptotic therapeutic approaches in liver diseases: do they really make sense?

A variety of data suggesting apoptotic cell death as a key feature of liver injury stimulated researchers to investigate the therapeutic potential of anti-apoptotic strategies in experimental models. However, the overestimated role of apoptotic cell death in liver injury has tempered the clinical translation of the protection afforded by anti-apoptotic regimes in experimental models. Thus, the hope for apoptosis modulation as potential treatment strategy for injured liver in humans could not be confirmed. Herein, we evaluated the degree of apoptosis in different hepatic stress models which are relevant for the human pathophysiology. Using morphological criteria of apoptosis, caspase-3 activation as well as TUNEL assay in combination with a positive control of apoptosis in liver injury, we quantified apoptotic cell death discriminating between parenchymal and non-parenchymal cells and confirmed these results by cleaved caspase-3 and PARP-1 protein expression. Discussing our findings and relating them to the existing literature on the potential role of apoptotic cell death, we strongly recommend reconsidering anti-apoptotic strategies to ameliorate liver injury efficiently.

Anti-proliferative effects of Siegesbeckia orientalis ethanol extract on human endometrial RL-95 cancer cells

Endometrial cancer is a common malignancy of the female genital tract. This study demonstrates that Siegesbeckia orientalis ethanol extract (SOE) significantly inhibited the proliferation of RL95-2 human endometrial cancer cells. Treating RL95-2 cells with SOE caused cell arrest in the G2/M phase and induced apoptosis of RL95-2 cells by up-regulating Bad, Bak and Bax protein expression and down-regulation of Bcl-2 and Bcl-xL protein expression. Treatment with SOE increased protein expression of caspase-3, -8 and -9 dose-dependently, indicating that apoptosis was through the intrinsic and extrinsic apoptotic pathways. Moreover, SOE was also effective against A549 (lung cancer), Hep G2 (hepatoma), FaDu (pharynx squamous cancer), MDA-MB-231 (breast cancer), and especially on LNCaP (prostate cancer) cell lines. In total, 10 constituents of SOE were identified by Gas chromatography-mass analysis. Caryophyllene oxide and caryophyllene are largely responsible for most cytotoxic activity of SOE against RL95-2 cells. Overall, this study suggests that SOE is a promising anticancer agent for treating endometrial cancer.

An algorithm that predicts the viability and the yield of human hepatocytes isolated from remnant liver pieces obtained from liver resections

Isolated human primary hepatocytes are an essential in vitro model for basic and clinical research. For successful application as a model, isolated hepatocytes need to have a good viability and be available in sufficient yield. Therefore, this study aims to identify donor characteristics, intra-operative factors, tissue processing and cell isolation parameters that affect the viability and yield of human hepatocytes. Remnant liver pieces from tissue designated as surgical waste were collected from 1034 donors with informed consent. Human hepatocytes were isolated by a two-step collagenase perfusion technique with modifications and hepatocyte yield and viability were subsequently determined. The accompanying patient data was collected and entered into a database. Univariate analyses found that the viability and the yield of hepatocytes were affected by many of the variables examined. Multivariate analyses were then carried out to confirm the factors that have a significant relationship with the viability and the yield. It was found that the viability of hepatocytes was significantly decreased by the presence of fibrosis, liver fat and with increasing gamma-glutamyltranspeptidase activity and bilirubin content. Yield was significantly decreased by the presence of liver fat, septal fibrosis, with increasing aspartate aminotransferase activity, cold ischemia times and weight of perfused liver. However, yield was significantly increased by chemotherapy treatment. In conclusion, this study determined the variables that have a significant effect on the viability and the yield of isolated human hepatocytes. These variables have been used to generate an algorithm that can calculate projected viability and yield of isolated human hepatocytes. In this way, projected viability can be determined even before isolation of hepatocytes, so that donors that result in high viability and yield can be identified. Further, if the viability and yield of the isolated hepatocytes is lower than expected, this will highlight a methodological problem that can be addressed.

Antiproliferative activity and induction of apoptotic by ethanolic extract of Alpinia galanga rhizhome in human breast carcinoma cell line

Background

We investigated the potential of galangal rhizomes to induce cytotoxic and apoptotic effects in the cultured human breast carcinoma cell line, (MCF-7) in compare with the non-malignant (MRC-5) cells.

Methods

Both cells were cultured in DMEM medium and treated with galangal rhizomes for three consecutive days. The percentage of apoptotic cells was determined by flow cytometry using Annexin-V fluorescein isothiocyanate.

Results

The results showed that the ethanolic extract of galangal rhizomes decreased cell viability in the malignant cells as a concentration- and time- dependent manner. The IC₅₀ values against MCF-7 were determined at 400.0 ± 11.7 and 170.0 ± 5.9 μg/ml after 48 and 72 h respectively. The morphology of MCF-7 cells treated with the ethanolic extract confirmed the cell proliferation assay results. Alpinia galanga induced apoptosis in MCF-7 cells, as determined by flow cytometry.

Conclusions

We concluded that the extract of Alpinia galanga exerts pro-apoptotic effects in a breast cancer-derived cell line and could be considered as a potential chemotherapeutic agent in breast cancer.

Molecular mechanisms of liver fibrosis in HIV/HCV coinfection

Chronic hepatitis C virus (HCV) infection is an important cause of morbidity and mortality in people coinfected with human immunodeficiency virus (HIV). Several studies have shown that HIV infection promotes accelerated HCV hepatic fibrosis progression, even with HIV replication under full antiretroviral control. The pathogenesis of accelerated hepatic fibrosis among HIV/HCV coinfected individuals is complex and multifactorial. The most relevant mechanisms involved include direct viral effects, immune/cytokine dysregulation, altered levels of matrix metalloproteinases and fibrosis biomarkers, increased oxidative stress and hepatocyte apoptosis, HIV-associated gut depletion of CD4 cells, and microbial translocation. In addition, metabolic alterations, heavy alcohol use, as well drug use, may have a potential role in liver disease progression. Understanding the pathophysiology and regulation of liver fibrosis in HIV/HCV co-infection may lead to the development of therapeutic strategies for the management of all patients with ongoing liver disease. In this review, we therefore discuss the evidence and potential molecular mechanisms involved in the accelerated liver fibrosis seen in patients coinfected with HIV and HCV.