Ghrelin reduces liver impairment in a model of concanavalin A-induced acute hepatitis in mice

Nuezhenoside G13 from Osmanthus fragrans fruit ameliorates Concanavalin A-induced autoimmune hepatitis by regulating the NF-κB/MAPK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Osmanthus fragrans fruit (OFF) exhibits hepatoprotective function, and it is consumed as food and used in traditional medicine in China. Nuezhenoside G13 (G13) is present in the highest levels in OFF. Autoimmune hepatitis (AIH) is a manifestation of liver disease and seriously endangers health. However, it remains unclear whether G13 affects AIH.

AIM OF THE STUDY

To clarify the effect of G13 on AIH and its exact underlying mechanism from a new perspective.

MATERIALS AND METHODS

We used a Concanavalin A-induced AIH mouse model and lipopolysaccharide-treated Raw264.7 cells to quantify serum biochemical indicators and confirm whether G13 exhibited protective effects in the AIH mice. Furthermore, we evaluated the effect of G13 via hematoxylin and eosin and immunohistochemical staining. We used enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction to quantify the inflammatory factors. We confirmed that G13 inhibited apoptosis via terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Molecular docking, immunofluorescence, and western blotting experiments of G13 and key proteins of the NF-κB/MAPK pathway revealed that G13 alleviated inflammation. In addition, Cell Counting Kit-8, ELISA, NO detection, and western blotting assays were performed. Finally, we used an inhibitor of the p38 MAPK to verify that G13 reduced inflammation through the NF-κB/MAPK pathway in Raw264.7 cells.

RESULTS

The in vivo experiments revealed that G13 improved oxidative stress and apoptosis. In addition, G13 decreased the expression levels of CD4+, CD8+, F4/80+, and Ly6G and the secretion of inflammatory factors. Interestingly, G13 reduced the phosphorylation levels of IκBα, NF-κB, JNK, ERK1/2, and p38. Additionally, the in vitro experiments revealed that G13 alleviated inflammation through the NF-κB/MAPK pathway in lipopolysaccharide-treated Raw264.7 cells. Furthermore, molecular docking demonstrated that the binding fraction of G13 with these proteins was high.

CONCLUSION

G13 suppressed oxidative stress, apoptosis, and inflammation in a Concanavalin A-induced AIH mouse model. Furthermore, G13 exerted its effect through the NF-κB/MAPK pathway.

Interleukin-22 alleviates alcohol-associated hepatic fibrosis, inhibits autophagy, and suppresses the PI3K/AKT/mTOR pathway in mice

BACKGROUND

Alcohol-associated hepatic fibrosis is a widespread liver disease with no effective treatment. Recent studies have indicated that interleukin-22 (IL-22) can ameliorate alcohol-associated liver disease. However, the mechanism underlying the role of IL-22 in alcohol-associated hepatic fibrosis remains unclear. Therefore, we investigated the effect of IL-22 in a mouse model of alcohol-associated hepatic fibrosis and its underlying mechanisms.

METHODS

Alcohol-associated hepatic fibrosis was induced by feeding male C57BL/6J mice with a Lieber-DeCarli liquid diet containing 4% ethyl alcohol for 8 weeks and injecting them with 5% tetrachloromethane (CCl₄ ) intraperitoneally for the last 4 weeks. During the last 4 weeks, IL-22 was also administered. We investigated the role of IL-22 in autophagy and the PI3K/AKT/mTOR signaling pathway using a 3-methyladenine intraperitoneal injection in the mice treated with IL-22. The effects of IL-22 on alcohol-associated hepatic fibrosis, autophagy-related gene expression, and PI3K/AKT/mTOR activity were assessed using histopathology, biochemical analysis, transmission electron microscopy, quantitative real-time PCR, immunohistochemistry, and western blotting.

RESULTS

Mice treated with ethanol and CCl₄ displayed distinct liver injuries, including hepatocyte necrosis, inflammatory cell infiltration, and hepatic fibrosis, which were substantially attenuated by IL-22 treatment. In addition, we found that IL-22 regulated the expression of autophagy-related genes and inhibited the PI3K/AKT/mTOR pathway, as evidenced by the reduction in p-PI3K, p-AKT, and p-mTOR expression after IL-22 treatment.

CONCLUSIONS

IL-22 exerts a marked protective effect against alcohol-associated hepatic fibrosis. Its effect may be partly related to the alteration of autophagy-related gene expression and inhibition of the PI3K/AKT/mTOR pathway in the liver.

Garcinone E Mitigates Oxidative Inflammatory Response and Protects against Experimental Autoimmune Hepatitis via Modulation of Nrf2/HO-1, NF-κB and TNF-α/JNK Axis

Garcinia mangostana L. (Clusiaceae), a popular tropical fruit for its juiciness and sweetness, is an opulent fountain of prenylated and oxygenated xanthones with a vast array of bio-activities. Garcinone E (GE), a xanthone derivative reported from G. mangostana, possesses cytotoxic and aromatase inhibitory activities. The present research endeavors to investigate the hepato-protection efficaciousness of GE on concanavalin-A (Con-A)-instigated hepatitis. Results showed that GE pretreating noticeably diminishes both the serum indices (transaminases, ALP, LDH, and γ-GT) and histopathological lesions of the liver. It counteracted neutrophil and CD4+ infiltration into the liver. GE furthered the Nrf2 genetic expression and its antioxidants' cascade, which resulted in amelioration of Con-A-caused oxidative stress (OS), lipid per-oxidative markers (4-HNE, MDA, PC) reduction, and intensified antioxidants (TAC, SOD, GSH) in the hepatic tissue. Additionally, GE prohibited NF-ĸB (nuclear factor kappa-B) activation and lessened the genetics and levels of downstream cytokines (IL1β and IL6). Moreover, the TNF-α/JNK axis was repressed in GE-treated mice, which was accompanied by attenuation of Con-A-induced apoptosis. These findings demonstrated the protective potential of GE in Con-A-induced hepatitis which may be associated with Nrf2/HO-1 signaling activation and OS suppression, as well as modulation of the NF-κB and TNF-α/JNK/apoptosis signaling pathway. These results suggest the potential use of GE as a novel hepato-protective agent against autoimmune hepatitis.

Salidroside in the Treatment of NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) is the commonest reason for chronic liver diseases in the world and is commonly related to the hepatic manifestation of the metabolic syndrome. Non-alcoholic steatohepatitis (NASH) is a deteriorating form of NAFLD, which can eventually develop into fibrosis, cirrhosis, and liver cancer. The reason for NAFLD/NASH development is complicated, such as liver lipid metabolism, oxidative stress, inflammatory response, apoptosis and autophagy, liver fibrosis and gut microbiota. Apart from bariatric surgery and lifestyle changes, officially approved drug therapy for NAFLD/NASH treatment is lacking. Salidroside (SDS) is a phenolic compound extensively distributed in the tubers of Rhodiola plants, which possesses many significant biological activities. This review summarized the related targets regulated by SDS in treating NAFLD/NASH. It is indicated that SDS could improve the status of NAFLD/NASH by ameliorating abnormal lipid metabolism, inhibiting oxidative stress, regulating apoptosis and autophagy, reducing inflammatory response, alleviating fibrosis and regulating gut microbiota. In conclusion, although the multiple bioactivities of SDS have been confirmed, the clinical data are inadequate and need to become the focus of attention in the later study.

Role of the Ghrelin System in Colitis and Hepatitis as Risk Factors for Inflammatory-Related Cancers

It is not known exactly what leads to the development of colorectal cancer (CRC) and hepatocellular carcinoma (HCC), but there are specific risk factors that increase the probability of their occurrence. The unclear pathogenesis, too-late diagnosis, poor prognosis as a result of high recurrence and metastasis rates, and repeatedly ineffective therapy of both cancers continue to challenge both basic science and practical medicine. The ghrelin system, which is comprised of ghrelin and alternative peptides (e.g., obestatin), growth hormone secretagogue receptors (GHS-Rs), and ghrelin-O-acyl-transferase (GOAT), plays an important role in the physiology and pathology of the gastrointestinal (GI) tract. It promotes various physiological effects, including energy metabolism and amelioration of inflammation. The ghrelin system plays a role in the pathogenesis of inflammatory bowel diseases (IBDs), which are well known risk factors for the development of CRC, as well as inflammatory liver diseases which can trigger the development of HCC. Colitis-associated cancer serves as a prototype of inflammation-associated cancers. Little is known about the role of the ghrelin system in the mechanisms of transformation of chronic inflammation to low- and high-grade dysplasia, and, finally, to CRC. HCC is also associated with chronic inflammation and fibrosis arising from different etiologies, including alcoholic and nonalcoholic fatty liver diseases (NAFLD), and/or hepatitis B (HBV) and hepatitis C virus (HCV) infections. However, the exact role of ghrelin in the progression of the chronic inflammatory lesions into HCC is still unknown. The aim of this review is to summarize findings on the role of the ghrelin system in inflammatory bowel and liver diseases in order to better understand the impact of this system on the development of inflammatory-related cancers, namely CRC and HCC.

Potential role of ghrelin in the regulation of inflammation

Several diseases are caused or progress due to inflammation. In the past few years, accumulating evidence suggests that ghrelin, a gastric hormone of 28-amino acid residue length, exerts protective effects against inflammation by modulating the related pathways. This review focuses on ghrelin's anti-inflammatory and potential therapeutic effects in neurological, cardiovascular, respiratory, hepatic, gastrointestinal, and kidney disorders. Ghrelin significantly alleviates excessive inflammation and reduces damage to different target organs mainly by reducing the secretion of inflammatory cytokines, including interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α), and inhibiting the nuclear factor kappa-B (NF-κB) and NLRP3 inflammasome signaling pathways. Ghrelin also regulates inflammation and apoptosis through the p38 MAPK/c-Jun N-terminal kinase (JNK) signaling pathway; restores cerebral microvascular integrity, and attenuates vascular leakage. Ghrelin activates the phosphoInositide-3 kinase (PI3K)/protein kinase B (Akt) pathway and inhibits inflammatory responses in cardiovascular diseases and acute kidney injury. Some studies show that ghrelin exacerbates colonic and intestinal manifestations of colitis. Interestingly, some inflammatory states, such as non-alcoholic steatohepatitis, inflammatory bowel diseases, and chronic kidney disease, are often associated with high ghrelin levels. Thus, ghrelin may be a potential new therapeutic target for inflammation-related diseases.

Cucurbitacin E glucoside alleviates concanavalin A-induced hepatitis through enhancing SIRT1/Nrf2/HO-1 and inhibiting NF-ĸB/NLRP3 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Cucurbitacins are highly oxygenated tetracyclic triterpenoids, that represent the major metabolites reported from C. colocynthis (L.) Schrad.. Cucurbitacin E glucoside (CuE) is a tetracyclic triterpene glycoside separated from Cucurbitaceae plants. CuE has potent anti-inflammatory, immunomodulatory, and anti-tumor properties.

AIM OF THE STUDY

The current study aimed at examining the hepatoprotective effect of CuE against concanavalin A (Con A)-produced hepatitis.

MATERIALS AND METHODS

Mice were intravenously administered Con A (15 mg/kg) to induce AIH. CuE was orally administered at two different doses for five days preceding Con A injection.

RESULTS

The results revealed that CuE pretreatment markedly attenuated the serum indices of hepatotoxicity and the severity of hepatic lesions. CuE depressed Con A-provoked increment in CD4⁺ T-cells in hepatic tissue. The antioxidant activity of CuE was evident through its ability to decrease markers of Con A-induced oxidative stress (malondialdehyde, 4-hydroxyenonanal, and protein carbonyl) and intensified the antioxidants in the hepatic tissue (SOD, GSH, and TAC). CuE increased mRNA expression of SIRT1 and Nrf2 as well as its binding capacity. Subsequently, CuE augmented mRNA expression of Nrf2 targeted genes as NQO1, GCL, and HO-1 and recovered its normal level. CuE inhibited the activation of NF-κB/downstream pro-inflammatory mediators signaling. Furthermore, CuE attenuated the mRNA expression of NLRP3 and its associated genes.

CONCLUSION

Collectively, these results demonstrated the remarkable hepatoprotective potential of CuE towards Con A-induced AIH which was mediated via suppression of oxidative stress, enhancing SIRT1/Nrf2/HO-1, and prohibition of the NF-κB/NLRP3 signaling. CuE could be a candidate for hepatitis patients.

Concanavalin A-induced autoimmune hepatitis model in mice: Mechanisms and future outlook

The concanavalin A (Con A)-induced liver injury mouse model is a typical animal model focusing on T cell-dependent hepatic damage in the field of autoimmune hepatitis (AIH). However, the underlying mechanism of hepatic dysfunction due to cell activation or signaling pathways triggered by Con A has not been fully clarified. Therefore, the controversy on this model remains in the academic community. In this article, we first summarized the merit and demerit of this contentious model from the perspectives of cell dysfunction, microcirculation disturbance, involved signaling pathways, as well as the properties of Con A. Then, we summed up the scientific implications of the model in elucidating the pathogenesis of AIH, and the shortcomings of this model were also summarized to elucidate the pathogenesis and application prospect of this classical liver injury mouse model in the study of AIH.

Daidzein ameliorated concanavalin A-induced liver injury through the Akt/GSK-3β/Nrf2 pathway in mice

Background

Daidzein is a soybean isoflavone that has been shown in previous studies to have anti-inflammatory and antioxidant effects. However, it remains unknown whether daidzein plays a protective role against concanavalin A (Con A)-induced autoimmune hepatitis (AIH).

Methods

In this study, an animal model of AIH was constructed by intravenous injection of Con A (15 mg/kg). Daidzein (200 mg/kg/d) was intraperitoneally administered to mice for 3 days before the Con A injection. Alpha mouse liver 12 (AML-12) cells were incubated in the absence or presence of daidzein to determine whether daidzein can alleviate Con A-induced hepatotoxicity.

Results

The findings showed that pretreatment with daidzein significantly reduced Con A-induced oxidative stress and hepatocyte apoptosis in Con A-induced liver injury. Pretreatment with daidzein significantly prevented the decrease of intrahepatic protein levels of phosphorylated Akt (p-Akt), phosphorylated GSK3β (p-GSK3β), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NOQ1 (NAD(P)H quinone dehydrogenase 1) in response to Con A administration. Meanwhile, malondialdehyde (MDA) production was reduced, and glutathione peroxidase (GPX), superoxide dismutase (SOD) activity, and SOD2 mRNA expression were elevated in daidzein-pretreated livers. In in vitro experiments, daidzein pretreatment prevented Con A-induced murine hepatocyte death. This effect was partly diminished by an inhibitor of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway.

Conclusions

These results indicate that daidzein pretreatment attenuates Con A-induced liver injury through the Akt/GSK3β/Nrf2 pathway. Our findings provide new insights into the use of plant-derived products for AIH treatment beyond immunosuppression.

Ghrelin and its role in gastrointestinal tract tumors (Review)

Ghrelin, an orexigenic hormone, is a peptide that binds to the growth hormone secretagogue receptor; it is secreted mainly by enteroendocrine cells in the oxyntic glands of the stomach. Ghrelin serves a role in both local and systemic physiological processes, and is implicated in various pathologies, including neoplasia, with tissue expression in several types of malignancies in both in vitro and in vivo studies. However, the precise implications of the ghrelin axis in metastasis, invasion and cancer progression regulation has yet to be established. In the case of gastrointestinal (GI) tract malignancies, ghrelin has shown potential to become a prognostic factor or even a therapeutic target, although data in the literature are inconsistent and unsystematic, with reports untailored to a specific histological subtype of cancer or a particular localization. The evaluation of immunohistochemical expression shows a limited outlook owing to the low number of cases analyzed, and in vivo analyses have conflicting data regarding differences in ghrelin serum levels in patients with cancer. The aim of this review was to examine the relationship between ghrelin and GI tract malignancies to demonstrate the inconsistencies in current results and to highlight its clinical significance in the outcome of these patients.

Ghrelin Regulates Cyclooxygenase-2 Expression and Promotes Gastric Cancer Cell Progression

Aim

To research the molecular mechanism of ghrelin in apoptosis, migratory, and invasion of gastric cancer (GC) cells.

Methods

After GC AGS cells were handled with ghrelin (10^–8 M), cyclooxygenase-2 inhibitor NS398 (100 μM), and Akt inhibitor perifosine (10uM), the rates of apoptosis were detected by TUNEL assay and flow cytometry assay. We assessed the expressions of PI3K, p-Akt, and COX-2 proteins by making use of Western blot analysis. The cell migratory and invasion were detected by using wound-healing and transwell analysis.

Results

The migratory and invasion were increased in ghrelin-treated cells, while the rates of apoptosis were decreased. GC AGS cells treated with ghrelin showed an increase in protein expression of p-Akt, PI3K, and COX-2. After cells were treated with Akt inhibitor perifosine, the protein expression of p-Akt, PI3K, and COX-2 and the cell migratory, invasion, and apoptosis were partly recovered. After cells were treated with cyclooxygenase-2 inhibitor NS398, the protein expression of COX-2 and the cell migratory and invasion were decreased, while the rates of apoptosis were increased.

Conclusion

Ghrelin regulates cell migration, invasion, and apoptosis in GC cells through targeting PI3K/Akt/COX-2. Ghrelin increases the expression of COX-2 in GC cells by targeting PI3K/Akt. Ghrelin is suggested to be one of the molecular targets in GC.

Regulatory effects of ghrelin on endoplasmic reticulum stress, oxidative stress, and autophagy: Therapeutic potential

Ghrelin is a regulatory peptide that is the endogenous ligand of the growth hormone secretagogue 1a (GHS-R1a) which belongs to the G protein-coupled receptor family. Ghrelin and GHS-R1a are widely expressed in the central and peripheral tissues and play therapeutic potential roles in the cytoprotection of many internal organs. Endoplasmic reticulum stress (ERS), oxidative stress, and autophagy dysfunction, which are involved in various diseases. In recent years, accumulating evidence has suggested that ghrelin exerts protective effects by regulating ERS, oxidative stress, and autophagy in diverse diseases. This review article summarizes information about the roles of the ghrelin system on ERS, oxidative stress, and autophagy in multiple diseases. It is suggested that ghrelin positively affects the treatment of diseases and may be considered as a therapeutic drug in many illnesses.

Summary of Natural Products Ameliorate Concanavalin A-Induced Liver Injury: Structures, Sources, Pharmacological Effects, and Mechanisms of Action

Liver diseases represent a threat to human health and are a significant cause of mortality and morbidity worldwide. Autoimmune hepatitis (AIH) is a progressive and chronic hepatic inflammatory disease, which may lead to severe complications. Concanavalin A (Con A)-induced hepatic injury is regarded as an appropriate experimental model for investigating the pathology and mechanisms involved in liver injury mediated by immune cells as well as T cell-related liver disease. Despite the advances in modern medicine, the only available strategies to treat AIH, include the use of steroids either solely or with immunosuppressant drugs. Unfortunately, this currently available treatment is associated with significant side-effects. Therefore, there is an urgent need for safe and effective drugs to replace and/or supplement those in current use. Natural products have been utilized for treating liver disorders and have become a promising therapy for various liver disorders. In this review, the natural compounds and herbal formulations as well as extracts and/or fractions with protection against liver injury caused by Con A and the underlying possible mechanism(s) of action are reviewed. A total of 53 compounds from different structural classes are discussed and over 97 references are cited. The goal of this review is to attract the interest of pharmacologists, natural product researchers, and synthetic chemists for discovering novel drug candidates for treating immune-mediated liver injury.

Stem cells from human exfoliated deciduous teeth ameliorate concanavalin A-induced autoimmune hepatitis by protecting hepatocytes from apoptosis

BACKGROUND

Autoimmune hepatitis is a serious autoimmune liver disease that threatens human health worldwide, which emphasizes the urgent need to identify novel treatments. Stem cells from human exfoliated deciduous teeth (SHED), which are easy to obtain in a non-invasive manner, show pronounced proliferative and immunomodulatory capacities.

AIM

To investigate the protective effects of SHED on concanavalin A (ConA)-induced hepatitis in mice, and to elucidate the associated regulatory mechanisms.

METHODS

We used a ConA-induced acute hepatitis mouse model and an in vitro co-culture system to study the protective effects of SHED on ConA-induced autoimmune hepatitis, as well as the associated underlying mechanisms.

RESULTS

SHED infusion could prevent aberrant histopathological liver architecture caused by ConA-induced infiltration of CD3⁺, CD4⁺, tumor necrosis-alpha⁺, and interferon-gamma⁺ inflammatory cells. Alanine aminotransferase and aspartate aminotransferase were significantly elevated in hepatitis mice. SHED infusion could therefore block ConA-induced alanine aminotransferase and aspartate aminotransferase elevations. Mechanistically, ConA upregulated tumor necrosis-alpha and interferon-gamma expression, which was activated by the nuclear factor-kappa B pathway to induce hepatocyte apoptosis, resulting in acute liver injury. SHED administration protected hepatocytes from ConA-induced apoptosis.

CONCLUSION

SHED alleviates ConA-induced acute liver injury via inhibition of hepatocyte apoptosis mediated by the nuclear factor-kappa B pathway. Our findings could provide a potential treatment strategy for hepatitis.

The new mechanism of Ghrelin/GHSR-1a on autophagy regulation

Autophagy is associated with several diseases. In recent years, accumulating evidence has suggested that ghrelin pathway exerts a protective effect by regulating autophagy. This review aims to assess the potential role and use of ghrelin as a new treatment for obesity, cardiovascular diseases, nonalcoholic fatty liver disease (NFALD), neurodegenerative diseases, and tissue damage associated with autophagy. Ghrelin reduces the basal expression of autophagy-related genes in obesity-associated type 2 diabetes and ghrelin level changes in obesity, heart failure, and NFALD as well as altered autophagy. Ghrelin and its receptor GHSR-1 activation induce the phosphorylation of ERK1/2 and the induction of PI-3 kinase (PI3 K) and phosphorylation of Akt. In the myocardium and hypothalamic NPY/AgRP neurons, ghrelin increases levels of the intracellular energy sensor AMPK and enhances autophagy, protecting cardiac ischemia and inducing neural stem cells. Nonetheless, ghrelin activates the PI3 K/Akt/Bcl-2 pathway and inhibits the activation of autophagy, such as tissues injured by sepsis or doxorubicin. In conclusion, endogenous ghrelin system could be considered as a new target or treatment for metabolism disorders, cardiac diseases, neurodegenerative diseases, and tissue injuries.

Mycophenolate mofetil attenuates concanavalin A-induced acute liver injury through modulation of TLR4/NF-κB and Nrf2/HO-1 pathways

BACKGROUND

Acute liver injury (ALI) is a serious health condition associated with rising morbidity and sudden progression. This study was designed to investigate the possible hepatocurative potential of two dose levels (30 and 60 mg/kg) of Mycophenolate mofetil (MMF), an immune-suppressant agent, against Concanavalin A (Con A)-induced ALI in mice.

METHOD

A single dose of Con A (20 mg/kg, IV) was used to induce ALI in mice. MMF (30 mg/kg and 60 mg/kg) was administered orally for 4 days post Con A injection.

RESULTS

MMF (30 mg/kg) failed to cause significant amelioration in Con A-induced ALI while MMF (60 mg/kg) significantly alleviated Con A-induced ALI. Administration of MMF (60 mg/kg) significantly decreased Con A-induced increase in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Additionally, MMF significantly restored the disrupted oxidant/antioxidants status induced by Con A. MMF caused marked increase in hepatic nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) levels. Moreover, MMF significantly reduced Con A-induced increase in the expression of hepatic toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), interferon-γ (INF-γ) and interleukin-1β (Il-1β). Also, MMF administration significantly decreased Con A-induced increase in the immune-expression of pro-apoptotic Bcl-2-associated X protein (Bax) and markedly increased Con A-induced decrease in the anti-apoptotic B-cell lymphoma 2 protein (Bcl2).

CONCLUSION

The observed ameliorative effect of MMF against Con A-induce ALI may be contributed to its anti-inflammatory, anti-oxidant and anti-apoptotic potentials taking into consideration that TLR4/NF-κB and Nrf2/HO-1 are the main implicated pathways. Schematic diagram summarizing the possible mechanisms underlying the ameliorative potential of Mycophenolate Mofetil against Con A-induced acute liver injury. Bax Bcl-2-associated X protein, Bcl2 B-cell lymphoma 2, MMF Mycophenolate mofetil, Con A Concanavalin A, GSH reduced glutathione, HO-1 Heme oxygenase-1, IL-1β Interleukin-1β, IFN-γ Interferon-γ, MDA Malondialdehyde, NF-κB Nuclear Factor Kappa B, Nrf2 Nuclear factor erythroid 2-related factor 2, NO Nitric Oxide, SOD Superoxide Dismutase, TLR4 Toll-like receptor 4, TNF-α tumor necrosis factor-α.

Ghrelin induces autophagy and CXCR4 expression via the SIRT1/AMPK axis in lymphoblastic leukemia cell lines

T cell acute lymphoblastic leukemia (T-ALL) is one of the most frequent malignancies in children, and the CXCR4 receptor plays an important role in the metastasis of this malignancy. Ghrelin is a hormone with various functions including stimulation of the release of growth hormone and autophagy in cancer cells. Moreover, SIRT1 and AMPK (AMP-activated protein kinase) stimulate expression of proteins involved in autophagy. On the other hand, autophagic cell death can be an alternative target for cancer therapy, in the absence of apoptosis. The relationship between ghrelin and the SIRT1/AMPK axis and the resulting effects on autophagy, apoptosis, proliferation, and expression of CXCR4 and the ghrelin receptor (GHS-R1a), in Jurkat and Molt-4 human lymphoblastic cell lines was not previously clear. Here we demonstrate that SIRT1 expression is upregulated during the induction of autophagy by ghrelin, an effect that is inhibited by inactivation of SIRT1/AMPK axis. In addition, ghrelin can affect CXCR4 and GHS-R1a expression. In conclusion, this work reveals that ghrelin induces autophagy, invasion, and downregulation of ghrelin receptor expression via the SIRT1/AMPK axis in lymphoblastic cell lines. However, in these cell lines ghrelin-induced autophagy does not lead to cell death due to weak induction of apoptosis.

A C21-Steroidal Glycoside from Cynanchum atratum Attenuates Concanavalin A-Induced Liver Injury in Mice

Cynatratoside A (CyA) is a C₂₁ Steroidal glycoside with pregnane skeleton isolated from the root of Cynanchum atratum Bunge (Asclepiadaceae). This study aimed to investigate the effects of CyA on concanavalin A (Con A)-induced autoimmune hepatitis (AIH) and the underlying mechanism. CyA was orally administered to mice at 10 and 40 mg/kg 8 h before and 1 h after Con A treatment. The effects of CyA on Con A-induced spleen and liver in mice were assessed via histopathological changes, T lymphocyte amounts and the expressions of IL-1β and ICAM-1. Con A-induced L-02 hepatocytes were used to evaluate whether CyA (0.1–10 μM) can directly protect hepatocytes from cytotoxicity and the possible mechanism. The results revealed that CyA treatment could significantly improve the histopathological changes of spleen and liver, reduce the proliferation of splenic T lymphocytes, and decrease the expressions of IL-1β and ICAM-1 in liver. The experiment in vitro showed that CyA inhibited Con A-induced hepatotoxicity in a concentration-dependent manner. CyA (10 μM) significantly increased/decreased the expression of Bcl-2/Bax and reduced the levels of cleaved caspases-9 and -3. Our study demonstrated for the first time that CyA has a significant protective effect on Con A-induced AIH by inhibiting the activation and adhesion of T lymphocytes and blocking hepatocyte apoptosis.

The Protective Effect of Sheep Placental Extract on Concanavalin A-induced Liver Injury in Mice

Though the biological effects of human placental extract have been widely studied, it has limited availability and its use poses ethical problems. Thus, domestic animal placental extracts are suggested as alternatives. In this study, the protective effect of sheep placental extract (SPE) on concanavalin A (Con A)-induced liver injury was investigated. BALB/c mice were randomly divided into six groups, including one normal group and five experimental groups, which received different oral doses of SPE (0, 5, 10 and 50 mg/kg) or a mixture of amino acids for 3 days before Con A injection. Compared with Con A-induced model group, the SPE administration significantly decreased serum aminotransaminase activity, alleviated pathological changes, recovered liver antioxidant capacity and prevented the increase of nitric oxide. Secretion of pro-inflammatory cytokines in serum decreased and mRNA expression of hepatic intercellular adhesion molecule-1, interferon-inducible chemokine 10 and inducible nitric oxide synthase were downregulated, while B-cell lymphoma-2 expression increased. The administration of amino acids mixture had no significant effect in most measurements compared with the model group, which indicated proteins and peptides, rather than individual amino acid, were largely responsible for the bioactivity of SPE. The results indicate SPE has potential therapeutic effects against immune-mediated hepatitis.

Effects of Ghrelin on the Apoptosis of Rheumatoid Arthritis Fibroblast-Like Synoviocyte MH7A Cells

Ghrelin is a circulating peptide hormone, which involved in promoting feeding and regulating energy metabolism in human and rodents. Abnormal synovial hyperplasia is the most important pathologic hallmark of rheumatoid arthritis (RA), which is characterised by tumor-like expansion. Existing studies indicated that there may exist some relation between the decreased ghrelin and the abnormally proliferating synovial cells in RA. Therefore, the aim of this study is to explore the apoptotic effects of ghrelin on MH7A synovial cells in vitro. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate the effects of ghrelin on the viability of MH7A cells. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) and flow cytometry were used to test the apoptotic effects of ghrelin. At last, Western blot and real-time PCR were performed to explore the expression of caspases-8, -9, and -3 after the treatment of ghrelin. MTT experiments showed that ghrelin could inhibit viability of MH7A cells. The results of flow cytometry and TUNEL showed that ghrelin could induce apoptosis of MH7A synovial cells. Western blot showed that expression of cleaved-caspases-8, -9, and -3 were increased in ghrelin stimulation group compared with the control group, while expression of pro-caspases-8, -9, and -3 had no significant difference. In mRNA levels, ghrelin can decrease pro-caspases-8, -9, and -3 mRNA expression, which confirmed the results of protein levels. Then these apoptotic effects were significantly reversed by [D-Lys₃] GHRP-6 (ghrelin receptor antagonist). This study found that ghrelin can induce apoptosis of MH7A cells through caspase signaling pathways.

Fucosterol Protects against Concanavalin A-Induced Acute Liver Injury: Focus on P38 MAPK/NF-κB Pathway Activity

Objective

Fucosterol is derived from the brown alga Eisenia bicyclis and has various biological activities, including antioxidant, anticancer, and antidiabetic properties. The aim of this study was to investigate the protective effects of fucosterol pretreatment on Concanavalin A- (ConA-) induced acute liver injury in mice, and to understand its molecular mechanisms.

Materials and Methods

Acute liver injury was induced in BALB/c mice by ConA (25 mg/kg), and fucosterol (dissolved in 2% DMSO) was orally administered daily at doses of 25, 50, and 100 mg/kg. The levels of hepatic necrosis, apoptosis, and autophagy associated with inflammatory cytokines were measured at 2, 8, and 24 h.

Results

Fucosterol attenuated serum liver enzyme levels and hepatic necrosis and apoptosis induced by TNF-α, IL-6, and IL-1β. Fucosterol also inhibited apoptosis and autophagy by upregulating Bcl-2, which decreased levels of functional Bax and Beclin-1. Furthermore, reduced P38 MAPK and NF-κB signaling were accompanied by PPARγ activation.

Conclusion

This study showed that fucosterol could alleviate acute liver injury induced by ConA by inhibiting P38 MAPK/PPARγ/NF-κB signaling. These findings highlight that fucosterol is a promising potential therapeutic agent for acute liver injury.

Salidroside mediates apoptosis and autophagy inhibition in concanavalin A-induced liver injury

Salidroside (Sal) is a glycoside extract from Rhodiola rosea L. with anti-inflammatory, antioxidant, anticancer and cardioprotective properties. The present study explored the protective effects and the possible mechanisms of Sal on concanavalin A (ConA)-induced liver injury in mice. Balb/C mice were divided into five groups: Normal control (injected with normal saline), ConA (25 mg/kg), Sal (10 mg/kg) +ConA, Sal (20 mg/kg) + ConA (Sal injected 2 h prior to ConA injection) and Sal (20 mg/kg) only. The serum levels of liver enzymes, pro-inflammatory cytokines, and apoptosis- and autophagy-associated marker proteins were determined at 2, 8 and 24 h after ConA injection. LY294002 was further used to verify whether the phosphoinositide 3-kinase (PI3K)/Akt pathway was activated. Primary hepatocytes were isolated to verify the effect of Sal in vitro. The results indicated that Sal was a safe agent to reduce pathological damage and serum liver enzymes in ConA-induced liver injury. Sal suppressed inflammatory reactions in serum and liver tissues, and activated the PI3K/Akt signaling pathway to inhibit apoptosis and autophagy in vivo and in vitro, which could be reversed by LY294002. In conclusion, Sal attenuated ConA-induced liver injury by modulating PI3K/Akt pathway-mediated apoptosis and autophagy in mice.

Pristimerin as a Novel Hepatoprotective Agent Against Experimental Autoimmune Hepatitis

Pristimerin (Pris) is bioactive natural quinonoid triterpene that has anti-inflammatory and anti-cancer activities. Meanwhile, its effect against hepatitis needs to be elucidated. This investigation aimed to evaluate the ability of Pris to protect against autoimmune hepatitis (AIH). A mouse model of AIH was established using single concanavalin A (Con A) intravenous injection. Mice were treated with Pris at two different doses (0.4 and 0.8 mg/kg) for 5 days prior to Con A challenge. Markers of hepatic injury, oxidative, inflammatory, and apoptotic damage were estimated. Results have revealed that Pris pretreatment ameliorated Con A-induced hepatic damage. There was decrease in the elevated serum indices of hepatic damage (ALT, AST, ALP, and LDH) and improvement of the histopathological picture of the liver. Pris effectively decreased Con A-induced neutrophil infiltration into the hepatic tissue as presented by amelioration of the level and immuno-expression of myeloperoxidase (MPO). Additionally, Pris attenuated Con A-induced increase in CD4+ T-cells in hepatic tissue. Lipid peroxidation was significantly depressed simultaneously with enhancement of the antioxidant capacity in Pris pretreated animals. Pris also enhanced nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA expression and its binding capacity. In addition, Pris increased mRNA expression of heme-oxygenase-1 (HO-1) and restored its normal level. Furthermore, Pris decreased the level and immuno-expression of nuclear factor kappa-B (NF-κB) as well as the downstream inflammatory cascade (TNF-α, IL-6, and IL-1β). Finally, Pris showed inhibitory effect on Con A-induced apoptotic alteration in liver as it decreased the mRNA expression and levels the apoptotic markers (Bax and caspase-3) and increased mRNA expression and level of the anti-apoptotic protein (Bcl2). In conclusion, this study demonstrates the potent hepatoprotective efficacy of Pris against Con A-induced hepatitis which may be related to anti-oxidative, anti-inflammatory, and anti-apoptotic pathways. Pris could serve as a new candidate for the management of hepatitis.

Quercetin prevents hepatic fibrosis by inhibiting hepatic stellate cell activation and reducing autophagy via the TGF-β1/Smads and PI3K/Akt pathways

The aim of this study was to investigate the effect of quercetin on hepatic fibrosis, a characteristic response to acute or chronic liver injury. Mice were randomized to bile duct ligation (BDL) or carbon tetrachloride (CCl₄) cirrhosis models. Quercetin (100 mg/kg or 200 mg/kg daily) was administered by gavage for 2 or 4 weeks. Liver tissue and blood samples were collected for histological and molecular analysis. The results of our experiments showed that quercetin reduced BDL or CCl₄ liver fibrosis, inhibited extracellular matrix formation, and regulated matrix metallopeptidase (MMP)-9 and tissue inhibitor of metalloproteinase (TIMP)-1. Quercetin attenuated liver damage by suppressing the TGF-β1/Smads signaling pathway and activating the PI3K/Akt signaling pathway to inhibit autophagy in BDL- or CCl₄- induced liver fibrosis. Quercetin prevented hepatic fibrosis by attenuating hepatic stellate cell activation and reducing autophagy through regulating crosstalk between the TGF-β1/Smads and PI3K/Akt pathways.

The protective effects of shikonin on hepatic ischemia/reperfusion injury are mediated by the activation of the PI3K/Akt pathway

Hepatic ischemia/reperfusion (I/R) injury, which can result in severe liver injury and dysfunction, occurs in a variety of conditions such as liver transplantation, shock, and trauma. Cell death in hepatic I/R injury has been linked to apoptosis and autophagy. Shikonin plays a significant protective role in ischemia/reperfusion injury. The purpose of the present study was to investigate the protective effect of shikonin on hepatic I/R injury and explore the underlying mechanism. Mice were subjected to segmental (70%) hepatic warm ischemia to induce hepatic I/R injury. Two doses of shikonin (7.5 and 12.5 mg/kg) were administered 2 h before surgery. Balb/c mice were randomly divided into four groups: normal control, I/R, and shikonin preconditioning at two doses (7.5 and 12.5 mg/kg). The serum and liver tissues were collected at three time points (3, 6, and 24 h). Shikonin significantly reduced serum AST and ALT levels and improved pathological features. Shikonin affected the expression of Bcl-2, Bax, caspase 3, caspase 9, Beclin-1, and LC3, and upregulated PI3K and p-Akt compared with the levels in the I/R group. Shikonin attenuated hepatic I/R injury by inhibiting apoptosis and autophagy through a mechanism involving the activation of PI3K/Akt signaling.

Effects of kinsenoside, a potential immunosuppressive drug for autoimmune hepatitis, on dendritic cells/CD8+ T cells communication in mice

The central purpose of this study was to investigate therapeutic effects of the botanical derivative, kinsenoside (KD), in experimental autoimmune hepatitis (AIH). Treatment with KD substantially reduced hepatic histopathological damage, induced by lymphocyte infiltration and proinflammatory cytokines, in concanavalin A-induced T-cell-mediated hepatitis, and in dendritic cells (DCs) loaded with hepatocellular carcinoma cells (DC/Hepa1-6) induced murine AIH. Interactions between immune cells after KD treatment in AIH were detected by anti-CD8 antibody blocking, CD8⁺ T cell sorting, and vaccinated mice with KD-pretreated DCs in a DC/Hepa1-6 model. These results showed that KD inhibited the elevated expressions of CD86 and major histocompatibility complex II, densities of chemokine receptor C-C chemokine receptor type 7, and extensive migration to lymph nodes, and increased the programmed death ligand 1 level of DCs, followed by suppressing CD8⁺ T cells, characterized as low differentiation and cytotoxicity, and eliciting cytokines balance. Furthermore, biochemical analysis, two-dimensional fingerprint screen and three-dimensional molecular docking results showed that KD bound to the vascular endothelial growth factor receptor 2 (VEGFR2) kinase domain, which inhibited the metabolism-related phosphatidylinositol 3 kinase/protein kinase B (PI3K-AKT) pathway in DCs and DC-modulated CD8⁺ T cells to lower the mitochondrial membrane potential and glucose/lipid utilization ratio in both cells. KD reversed activation of the PI3K-AKT pathway by 740 Y-P (PI3K agonist), thereby impeding the translocation and dimerization of signal transducer and activators of transcription (STAT) 3 and synergistically blocking the inflammation-related Janus kinase (JAK) 2/STAT3 pathway in DCs and DC-modulated T cells.

CONCLUSION

KD treatment elicits immunosuppression against autoimmune liver injury by targeting VEGFR2, followed by diminishing the cross-talk of metabolism-related PI3K-AKT and inflammation-related JAK2-STAT3 pathways, and thereby disrupts DC-induced cross-priming of CD8⁺ T cell responses. (Hepatology 2016;64:2135-2150).

Anti-inflammatory properties of the vagus nerve: potential therapeutic implications of vagus nerve stimulation

Brain and viscera interplay within the autonomic nervous system where the vagus nerve (VN), containing approximately 80% afferent and 20% efferent fibres, plays multiple key roles in the homeostatic regulations of visceral functions. Recent data have suggested the anti-inflammatory role of the VN. This vagal function is mediated through several pathways, some of them still debated. The first one is the anti-inflammatory hypothalamic-pituitary-adrenal axis which is stimulated by vagal afferent fibres and leads to the release of cortisol by the adrenal glands. The second one, called the cholinergic anti-inflammatory pathway, is mediated through vagal efferent fibres that synapse onto enteric neurons which release acetylcholine (ACh) at the synaptic junction with macrophages. ACh binds to α-7-nicotinic ACh receptors of those macrophages to inhibit the release of tumour necrosis (TNF)α, a pro-inflammatory cytokine. The last pathway is the splenic sympathetic anti-inflammatory pathway, where the VN stimulates the splenic sympathetic nerve. Norepinephrine (noradrenaline) released at the distal end of the splenic nerve links to the β2 adrenergic receptor of splenic lymphocytes that release ACh. Finally, ACh inhibits the release of TNFα by spleen macrophages through α-7-nicotinic ACh receptors. Understanding of these pathways is interesting from a therapeutic point of view, since they could be targeted in various ways to stimulate anti-inflammatory regulation in TNFα-related diseases such as inflammatory bowel disease and rheumatoid arthritis. Among others, VN stimulation, either as an invasive or non-invasive procedure, is becoming increasingly frequent and several clinical trials are ongoing to evaluate the potential effectiveness of this therapy to alleviate chronic inflammation.

15d-PGJ2 alleviates ConA-induced acute liver injury in mice by up-regulating HO-1 and reducing hepatic cell autophagy

OBJECTIVE

In this study, we confirmed a protective effect of 15d-PGJ2 in concanavalin A (ConA)-induced fulminant hepatitis in mice and investigated the potential mechanism.

MATERIALS AND METHODS

Balb/C mice were injected with ConA (25mg/kg) to induce acute fulminant hepatitis, and 15d-PGJ2 (2.5-10μg) was administered 30min after the ConA injection. The histological grade, pro-inflammatory cytokine and ROS levels, apoptosis and autophagy activity, the expression of HO-1, Nrf2, JNK and Bcl-2 activity were determined 2, 4, and 8h after the ConA injection.

RESULTS

Following ConA challenge, the expression of cytokines tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) was up-regulated. Treatment with 15d-PGJ2 reduced the pathological effects of ConA-induced fulminant hepatitis and significantly reduced the levels of TNF-α, IL-1β and ROS after injection. 15d-PGJ2 inhibited apoptosis and autophagic cell death, facilitated Nrf2 nuclear translocation, increased HO-1 expression and suppressed the JNK activation.

CONCLUSION

15d-PGJ2 alleviates ConA-induced acute liver injury in mice by up-regulating the anti-oxidative stress factor HO-1 and reducing the production of cytokines and ROS, thereby inhibiting hepatic cell autophagy probably induced by ROS.

Epigallocatechin-3-gallate attenuates apoptosis and autophagy in concanavalin A-induced hepatitis by inhibiting BNIP3

Background

Epigallocatechin-3-gallate (EGCG) is the most effective compound in green tea, and possesses a wide range of beneficial effects, including anti-inflammatory, antioxidant, antiobesity, and anticancer effects. In this study, we investigated the protective effects of EGCG in concanavalin A (ConA)-induced hepatitis in mice and explored the possible mechanisms involved in these effects.

Methods

Balb/C mice were injected with ConA (25 mg/kg) to induce acute autoimmune hepatitis, and EGCG (10 or 30 mg/kg) was administered orally twice daily for 10 days before ConA injection. Serum liver enzymes, proinflammatory cytokines, and other marker proteins were determined 2, 8, and 24 hours after the ConA administration.

Results

BNIP3 mediated cell apoptosis and autophagy in ConA-induced hepatitis. EGCG decreased the immunoreaction and pathological damage by reducing inflammatory factors, such as TNF-α, IL-6, IFN-γ, and IL-1β. EGCG also exhibited an antiapoptotic and antiautophagic effect by inhibiting BNIP3 via the IL-6/JAKs/STAT3 pathway.

Conclusion

EGCG attenuated liver injury in ConA-induced hepatitis by downregulating IL-6/JAKs/STAT3/BNIP3-mediated apoptosis and autophagy.

Protective effect of fucoidan from Fucus vesiculosus on liver fibrosis via the TGF-β1/Smad pathway-mediated inhibition of extracellular matrix and autophagy

Liver fibrosis is a dynamic reversible pathological process in the development of chronic liver disease to cirrhosis. However, the current treatments are not administered for a long term due to their various side effects. Autophagy is initiated to decompose damaged or excess organelles, which had been found to alter the progression of liver fibrosis. In this article, we hypothesized that fucoidan from Fucus vesiculosus may attenuate liver fibrosis in mice by inhibition of the extracellular matrix and autophagy in carbon tetrachloride- and bile duct ligation-induced animal models of liver fibrosis. The results were determined using enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemical staining. Fucoidan from F. vesiculosus could inhibit the activation of hepatic stellate cells and the formation of extracellular matrix and autophagosomes, and its effect may be associated with the downregulation of transforming growth factor beta 1/Smads pathways. Fucoidan, as an autophagy and transforming growth factor beta 1 inhibitor, could be a promising potential therapeutic agent for liver fibrosis.