Pretreatment with propylene glycol alginate sodium sulfate ameliorated concanavalin A-induced liver injury by regulating the PI3K/Akt pathway in mice

Sulfated Alginate for Biomedical Applications

Alginate (Alg) polymers have received much attention due to the mild conditions required for gel formation and their good bio-acceptability. However, due to limited interactions with cells, many drugs, and biomolecules, chemically modified alginates are of great interest. Sulfated alginate (S-Alg) is a promising heparin-mimetic that continues to be investigated both as a drug molecule and as a component of biomaterials. Herein, the S-Alg literature of the past five years (2017-2023) is reviewed. Several methods used to synthesize S-Alg are described, with a focus on new advances in characterization and stereoselectivity. Material fabrication is another focus and spans bulk materials, particles, scaffolds, coatings, and part of multicomponent biomaterials. The new application of S-Alg as an antitumor agent is highlighted together with studies evaluating safety and biodistribution. The high binding affinity of S-Alg for various drugs and heparin-binding proteins is exploited extensively in biomaterial design to tune the encapsulation and release of these agents and this aspect is covered in detail. Recommondations include publishing key material properties to allow reproducibility, careful selection of appropriate sulfation strategies, the use of cross-linking strategies other than ionic cross-linking for material fabrication, and more detailed toxicity and biodistribution studies to inform future work.

Therapeutic potential of oleanolic acid in liver diseases

Liver-associated diseases affect millions of individuals worldwide. In developed countries, the incidence of viral hepatitis is reducing due to advancements in disease prevention, diagnosis, and treatment. However, with improvements in living standards, the prevalence of metabolic liver diseases, such as non-alcoholic fatty liver disease and alcohol-related liver disease, is expected to increase; notably, this rise in the prevalence of metabolic liver disease can lead to the development of more severe liver diseases, including liver failure, cirrhosis, and liver cancer. The growing demand for natural alternative therapies for chronic diseases has highlighted the importance of studying the pharmacology of bioactive compounds in plants. One such compound is oleanolic acid (OA), a pentacyclic triterpenoid known for its antioxidant, anti-inflammatory, anti-ulcer, antibacterial, antiviral, antihypertensive, anti-obesity, anticancer, anti-diabetic, cardioprotective, hepatoprotective, and anti-neurodegenerative properties. Recent studies have demonstrated that OA treatment can reduce the risk of pathological liver damage, ultimately alleviating liver dysregulation and restoring overall liver function. This review aims to explore the latest research on the biological effects of OA and its derivatives. Notably, it explores the mechanisms of action of these compounds in both in vitro and in vivo research models and, ultimately, highlights OA as a promising candidate for alternative therapies in the treatment and management of chronic liver disease.

Itaconate attenuates autoimmune hepatitis via PI3K/AKT/mTOR pathway-mediated inhibition of dendritic cell maturation and autophagy

Autoimmune hepatitis (AIH) results from an autoimmune-mediated chronic inflammatory response against liver cells. Defective self-tolerance and dysfunctional dendritic cells (DCs) play a regulatory role in AIH. Itaconate has recently attracted attention in the field of immunometabolism because of its crucial role as an anti-inflammatory metabolite that negatively regulates the inflammatory response. However, the underlying mechanism of itaconate mediation of DCs in AIH remains unclear. In this study, we found that itaconate acts as an anti-inflammatory factor in the liver. Endogenous itaconate levels were significantly increased in mice with S100-induced AIH model and correlated with upregulation of the immune-responsive gene 1 expression. However, the anti-inflammatory response from endogenously itaconate may not represent the effects exogenously-produced itaconate. We investigated the anti-inflammatory response from exogenous itaconate in S100-induced AIH, and our results showed that itaconate treatment attenuated liver histopathological damage, hepatocyte apoptosis, aminotransferase elevation, and IL-6 production in the S100-induced AIH model. In addition, Itaconate decreased glycolysis to suppress the maturation of DCs in the liver and spleen of AIH models, thereby directly regulating differentiation of Th17 and Tregs in vivo. The percentage of Th17 cells among the CD4⁺ population were decreased and Tregs were increased (P < 0.05). Furthermore, Itaconate-induced bone marrow-derived monocytes suppressed CD4⁺cells proliferation. In vitro and in vivo, we found that itaconate suppressed autophagy via activating the PI3K/AKT/mTOR signalling pathway in bone marrow-derived DCs and liver tissues. We further investigated the function of Itaconate on DC-specific mTOR-deficient mice. mTOR-deficient DCs augmented inflammatory reactions in mTOR^DC-/- AIH mice and induced autophagy. MHY1485 (an agonist of mTOR) and itaconate significantly alleviated the inflammatory reaction and autophagy signalling. In conclusion, itaconate ameliorate liver inflammation in S100-induced AIH mice by regulating the PI3K/AKT/mTOR pathway to decrease DCs autophagy and maturation. These results provide insight useful for treating AIH.

Construction and function analysis of the LncRNA-miRNA-mRNA competing endogenous RNA network in autoimmune hepatitis

AIMS

To construct the lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network based on our microarray chip data for providing new insights into the pathogenesis of autoimmune hepatitis.

METHODS

The ceRNA pairs were obtained by calculating the co-expression relationships among the differentially expressed lncRNAs (DELs), differentially expressed microRNAs (DEMis), and differentially expressed mRNAs (DEMs) with Pearson correlation analysis and hypergeometric distribution. The data of the differentially expressed genes were obtained from our previous studies in the concanavalin A-induced AIH mouse model. The biological functions of the ceRNA network were revealed by carrying out the GO and KEGG enrichment analysis. The expression of some differentially expressed genes constructed in the ceRNA pair was validated, and the correlation to liver injury was analyzed.

RESULTS

The mRNAs constructed in the ceRNA network were most significantly annotated in the GO terms of "inflammatory response" and enriched in "Cytokine-cytokine receptor interaction" and "MAPK signaling pathway". The differences in the expression of Gm38975, mmu-miR-125a-3p, and Map3k13 between the model group and control group were significant, and the expression of these genes at a transcriptional level was positively or negatively correlated to the activity of ALT and AST as well as the amount of MDA and NO.

CONCLUSION

Our work is the first in its kind to predict and illustrate the comprehensive lncRNA-miRNA-mRNA ceRNA network associated with the etiopathogenesis of AIH. This study indicates to lay the foundation for revealing the potential roles of ceRNAs in the occurrence of AIH and provide novel treatment targets for this disease.

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.

Pathogenesis of Concanavalin A induced autoimmune hepatitis in mice

Autoimmune hepatitis (AIH) is an autoimmune disease characterized by liver parenchymal destruction and chronic fibrosis. Its exact etiology and pathogenesis are not yet fully understood.(Please connect with the following, do not leave a line) Concanavalin A (Con A)-induced mice hepatitis model is a liver injury mediated by T cell and macrophage activation, and its pathogenesis and pathological changes are similar to human AIH. The establishment of this model has greatly promoted the research progress of AIH pathogenesis. However, the exact mechanism of Con A induced liver injury in mice, and its possible defects or deficiencies, has not yet been described in a clear and detailed manner. Therefore, the model has some limitations when applied to the study of the pathogenesis and treatment mechanism of AIH. This article reveals the pathogenesis of Con A induced liver injury in mice from the aspects of immune disorder and coagulation mechanism, expounds the significance of non-coding RNA in this model, summarizes the signal transduction pathways involved in this model, and summarizes the advantages and disadvantages of the model, which provides a theoretical basis and research target for the application of Con A induced liver injury model in AIH in the future.

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.

Application of marine natural products in drug research

New diseases are emerging as the environment changes, so drug manufacturers are always on the lookout for new resources to develop effective and safe drugs. In recent years, many bioactive substances have been produced in the marine environment, which represents an alternative resource for new drugs used to combat major diseases such as cancer or inflammation. Many marine-derived medicinal substances are in preclinical or early stage of clinical development, and some marine drugs have been put on the market, such as ET743 (Yondelis®). This review presents the sources, activities, mechanisms of action and syntheses of bioactive substances based on marine natural products in clinical trials and on the market, which is helpful to understand the progress of drug research by application of marine natural products.

Effect of Propylene Glycol Alginate Sodium Sulfate Nanoparticles on Myocardial Injury in Diabetic Rats via Silent Information Regulator 1/ Hypoxia-Inducible Factor-1 Alpha Pathway

The main purpose of this paper is to study the effect of propylene glycol alginate sodium sulfite nanoparticles on myocardial injury in diabetic rats through Sirt1/HIF-1 α signal pathway. The effects of different doses of propylene glycol alginate sodium sulfite nanoparticles on the content of malondialdehyde, creatine kinase, nitric oxide, the activity of superoxide dismutase, lactate dehydrogenase and nitric oxide synthetase in the myocardial tissue of diabetic rats observed. The function indexes of HIF-1 α mitochondria and measured the expression of Sirt1/HIF-1 α pathway. The results show that compare with the diabetic model group, the blood glucose level of the rats in the propylene glycol alginate sodium sulfite nanoparticles treatment group was slightly low. The serum LDH, CK and MDA contents were significantly low, and the activity of SOD in the myocardium in the propylene glycol alginate sodium sulfite nanoparticles treatment group was significantly higher than that in the diabetic model group in the treatment group. The activity of NOS and the content of MDA and no were lower than that in the diabetic rats, the expression of Sirt1 and HIF-1α in myocardial tissue was increased. It suggested that propylene glycol alginate sodium sulfite nanoparticles alleviate myocardial damage in diabetic rats by regulating Sirt1/HIF-1α signal pathway, improving mitochondrial function and inhibiting oxidative stress.

PPARγ/NF-κB and TGF-β1/Smad pathway are involved in the anti-fibrotic effects of levo-tetrahydropalmatine on liver fibrosis

Liver fibrosis is a necessary stage in the development of chronic liver diseases to liver cirrhosis. This study aims to investigate the anti‐fibrotic effects of levo‐tetrahydropalmatine (L‐THP) on hepatic fibrosis in mice and cell models and its underlying mechanisms. Two mouse hepatic fibrosis models were generated in male C57 mice by intraperitoneal injection of carbon tetrachloride (CCl4) for 2 months and bile duct ligation (BDL) for 14 days. Levo‐tetrahydropalmatine was administered orally at doses of 20 and 40 mg/kg. An activated LX2 cell model induced by TGF‐β1 was also generated. The results showed that levo‐tetrahydropalmatine alleviated liver fibrosis by inhibiting the formation of extracellular matrix (ECM) and regulating the balance between TIMP1 and MMP2 in the two mice liver fibrosis models and cell model. Levo‐tetrahydropalmatine inhibited activation and autophagy of hepatic stellate cells (HSCs) by modulating PPARγ/NF‐κB and TGF‐β1/Smad pathway in vivo and in vitro. In conclusion, levo‐tetrahydropalmatine attenuated liver fibrosis by inhibiting ECM deposition and HSCs autophagy via modulation of PPARγ/NF‐κB and TGF‐β1/Smad pathway.

Neuregulin-1β Protects the Rat Diaphragm during Sepsis against Oxidative Stress and Inflammation by Activating the PI3K/Akt Pathway

Sepsis-induced diaphragm dysfunction (SIDD) which is mainly characterized by decrease in diaphragmatic contractility has been identified to cause great harms to patients. Therefore, there is an important and pressing need to find effective treatments for improving SIDD. In addition, acetylcholinesterase (AChE) activity is a vital property of the diaphragm, so we evaluated both diaphragmatic contractility and AChE activity. Though neuregulin-1β (NRG-1β) is known to exert organ-protective effects in some inflammatory diseases, little is known about the potential of NRG-1β therapy in the diaphragm during sepsis. Our study was aimed at exploring the effects of NRG-1β application on diaphragmatic contractility and AChE activity during sepsis. Proinflammatory cytokines, muscle injury biomarkers in serum, contractile force, AChE activity, proinflammatory cytokines, oxidative parameters, histological condition, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, and expression of phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB/Akt) signaling proteins in the diaphragm were measured and compared between nonseptic and septic groups with or without NRG-1β treatment. In vitro, the effects of NRG-1β on reactive oxygen species (ROS) production in the lipopolysaccharide- (LPS-) stimulated L6 rat muscle skeletal cells with or without the Akt inhibitor MK-2206 were detected. NRG-1β inhibited proinflammatory cytokine release and muscle injury biomarkers soaring in serum and improved the sepsis-induced diaphragm dysfunction and AChE activity decrease significantly during sepsis. Meanwhile, the inflammatory response, oxidative stress, pathological impairment, and cell apoptosis in the diaphragm were mitigated by NRG-1β. And NRG-1β activated the PI3K/Akt signaling in the diaphragm of septic rats. Elevated ROS production in the LPS-stimulated L6 rat skeletal muscle cells was reduced after treatment with NRG-1β, while MK-2206 blocked these effects of NRG-1β. In conclusion, our findings underlined that NRG-1β could reduce circulating levels of proinflammatory cytokines in rats with sepsis, adjust diaphragmatic proinflammatory cytokine level, mitigate diaphragmatic oxidative injury, and lessen diaphragm cell apoptosis, thereby improving diaphragmatic function, and play a role in diaphragmatic protection by activating PI3K/Akt signaling.

Pyrazinamide enhances lipid peroxidation and antioxidant levels to induce liver injury in rat models through PI3k/Akt inhibition

Pyrazinamide (PZA) is an anti-tuberculosis drug known to causes liver injury. phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) signaling protects against liver injury by promoting cellular antioxidant defenses and reducing intracellular reactive oxygen species (ROS) and lipid peroxidation. The regulatory mechanisms and functions of PI3K/Akt signaling during the hepatotoxicity of PZA are however not fully understood. Rats were administered PZA or/and the PI3K activator (740Y-P) for 7 days. The levels of serum parameters were examined via standard enzymatic techniques and the pathological status of the liver was confirmed by H & E staining. The levels of lipid peroxidation and antioxidant production were determined using commercial kits. Liver apoptosis was assessed by TUNEL staining. The expression of apoptosis-related proteins and PI3K/Akt signaling were assessed by western blot analysis. PZA treatment significantly increased serum alanine transaminase, aspartate transaminase, gamma-glutamyl transpeptidase and tall bilirubin leading to liver damage in rats. PZA also facilitated lipid peroxidation and suppressed antioxidant defenses. PZA led to apoptotic induction in rat liver cells through the downregulation of Bcl-2 and the upregulation of Bax and caspase-3. PZA also dramatically inhibited PI3K/Akt signaling in rat liver cells. We further verified that PI3K/Akt signaling in response to 740Y-P could attenuate hepatic injury, lipid peroxidation and apoptosis in rat liver cells in response to PZA. We reveal that PZA-induced liver injury in rats occurs through PI3k/Akt signaling, the recovery of which prevents liver injury in rat models.

TGF-β/Smad and JAK/STAT pathways are involved in the anti-fibrotic effects of propylene glycol alginate sodium sulphate on hepatic fibrosis

Liver fibrosis, a consequence of unhealthy modern lifestyles, has a growing impact on human health, particularly in developed countries. Here, we have explored the anti‐fibrotic effects of propylene glycol alginate sodium sulphate (PSS), a natural extract from brown algae, in fibrotic mice and cell models. Thus, we established bile duct ligature and carbon tetrachloride mouse models and LX‐2 cell models with or without PSS treatment. Liver pathological sections and the relevant indicators in serum and liver tissues were examined. PSS prevented hepatic injury and fibrosis to a significant extent, and induced up‐regulation of matrix metalloproteinase‐2 and down‐regulation of tissue inhibitor of metalloproteinase‐1 through suppressing the transforming growth factor β1 (TGF‐β1)/Smad pathway. PSS additionally exerted an anti‐autophagy effect through suppressing the Janus kinase (JAK) 2/transducer and activator of transcription 3 (STAT3) pathway. In conclusion, PSS prevents hepatic fibrosis by suppressing inflammation, promoting extracellular matrix (ECM) decomposition and inactivating hepatic stellate cells through mechanisms involving the TGF‐β1/Smad2/3 and JAK2/STAT3 pathways in vivo and in vitro.

Simvastatin re-sensitizes hepatocellular carcinoma cells to sorafenib by inhibiting HIF-1α/PPAR-γ/PKM2-mediated glycolysis

BACKGROUND

Hepatocellular carcinoma (HCC) is a common primary malignant tumor which usually progresses to an advanced stage because of late diagnosis. Sorafenib (Sora) is a first line medicine for advanced stage HCC; however, it has been faced with enormous resistance. Simvastatin (Sim) is a cholesterol-lowering drug and has been reported to inhibit tumor growth. The present study aims to determine whether Sora and Sim co-treatment can improve Sora resistance in HCC.

METHODS

The HCC cell line LM3 and an established Sora-resistant LM3 cell line (LM3-SR) were used to study the relationship between Sora resistance and aerobic glycolysis. Cell proliferation, apoptosis and glycolysis levels were analyzed by western blotting, flow cytometry analysis and biomedical tests. A xenograft model was also used to examine the effect of Sim in vivo. Detailed mechanistic studies were also undertaken by the use of activators and inhibitors, and lentivirus transfections.

RESULTS

Our results demonstrated that the resistance to Sora was associated with enhanced aerobic glycolysis levels. Furthermore, LM3-SR cells were more sensitive to Sim than LM3 cells, suggesting that combined treatment with both Sora and Sim could enhance the sensitivity of LM3-SR cells to Sora. This finding may be due to the suppression of the HIF-1α/PPAR-γ/PKM2 axis.

CONCLUSIONS

Simvastatin can inhibit the HIF-1α/PPAR-γ/PKM2 axis, by suppressing PKM2-mediated glycolysis, resulting in decreased proliferation and increased apoptosis in HCC cells, and re-sensitizing HCC cells to Sora.

Role of Thymoquinone in Cardiac Damage Caused by Sepsis from BALB/c Mice

Sepsis is a major health complication causing patient mortality and increased healthcare costs. Cardiac dysfunction, an important consequence of sepsis, affects mortality. We previously reported that thymoquinone (TQ) protected against hyperlipidemia and doxorubicin-induced cardiac damage. This study investigated the possible protective effects of TQ against cardiac damage in septic BALB/c mice. Eight-week-old male BALB/c mice were divided into four groups: control, TQ, cecal ligation and puncture (CLP), and TQ + CLP. CLP was performed after 2-week TQ gavage. After 48 h, we measured the histopathological alterations of the cardiac tissue and the plasma levels of troponin-T (cTnT) and ATP. We evaluated autophagy (p62 and beclin 1), pyroptosis (NLRP3, caspase-1, interleukin [IL]-1β, and IL-18) at the gene and protein levels and IL-6 and tumor necrosis factor-α (TNF-α) at the gene level. Our results demonstrated that TQ administration significantly reduced intestinal histological alterations. TQ inhibited plasma cTnT levels; improved ATP; significantly inhibited p62, NLRP3, caspase-1, IL-1β, IL-18, IL-6, TNF-α, and MCP-1expressions; and increased beclin 1 and IL-10 level. The phosphatidylinositide 3-kinase level was significantly decreased in the TQ + CLP group versus the CLP group. These results suggest that TQ effectively modulates autophagy, pyroptosis, and pro-inflammatory, making it important in the treatment of sepsis-induced cardiac damage.

Protective effects of levo-tetrahydropalmatine on hepatic ischemia/reperfusion injury are mediated by inhibition of the ERK/NF-κB pathway

BACKGROUND

Hepatic ischemia/reperfusion (IR) injury is a common medical phenomenon that occurs during a number of clinical conditions, such as liver transplantation, severe injuries, and shock. In our study, we determined the protective functions of levo-tetrahydropalmatine (L-THP) on hepatic IR injury in mice by inhibiting the ERK/NF-κB signaling pathway.

METHOD

BALB/c mice were randomly divided into six groups as follows: normal control (NC); sham; L-THP (40 mg/kg); IR; L-THP (20 mg/kg) + IR; and L-THP (40 mg/kg) + IR. Liver tissues and sera were collected at three time points after reperfusion (2, 8, and 24 h). The liver enzyme, inflammatory factor, and other protein levels in the serum and liver tissues were detected.

RESULTS

L-THP pretreatment alleviated hepatocyte injury caused by IR and reduced the production of proinflammatory cytokines, such as IL-6 and TNF-α. Furthermore, L-THP could inhibit the ERK/NF-κB signaling pathway to attenuate hepatocyte apoptosis and autophagy. And the protective effect of L-THP is positively correlated with its dose.

CONCLUSION

L-THP protects the liver from IR injury by inhibiting the release of inflammatory factors and alleviating liver cell apoptosis and autophagy. The protective functions of L-THP may be partly based on the downregulation of the ERK/NF-κB pathway.

The Protective Effects of Levo-Tetrahydropalmatine on ConA-Induced Liver Injury Are via TRAF6/JNK Signaling

Aims

Levo-tetrahydropalmatine (L-THP) is an active ingredient of Corydalis yanhusuo W. T. Wang, which has many bioactive properties. Herein, we investigated the protective effects of L-THP on concanavalin A- (ConA-) induced hepatitis in mice and explored its possible mechanisms of these effects.

Main Methods

Balb/c mice were intravenously injected with 25 mg/kg ConA to generate a model of acute autoimmune hepatitis, and L-THP (20 or 40 mg/kg) was administered orally once daily for 5 d before the ConA injection. The liver enzyme levels, proinflammatory cytokine levels, and other marker protein levels were determined 2, 8, and 24 h after ConA injection.

Results

L-THP could decrease serum liver enzymes and pathological damage by reducing the release of inflammatory factors like IL-6 and TNF-α. The results of Western Blot and PCR indicated that L-THP could ameliorate liver cell apoptosis and autophagy. L-THP could suppress T lymphocyte proliferation and the production of TNF-α and IL-6 induced by ConA in a dose-dependent manner in vitro. Additionally, the protective functions of L-THP depended on downregulating TRAF6/JNK signaling. Conclusion. The present study indicated that L-THP attenuated acute liver injury in ConA-induced autoimmune hepatitis by inhibiting apoptosis and autophagy via the TRAF6/JNK pathway.

Isorhamnetin: A hepatoprotective flavonoid inhibits apoptosis and autophagy via P38/PPAR-α pathway in mice

Isorhamnetin, a flavonoid compound extracted from plants' fruit or leaves, like sea buckthorn (Hippophae rhamnoides L.), has many biological functions, including anti-tumor, anti-oxidant and anti-inflammatory effect. The present study is in order to explore the hepatoprotective effect of isorhamnetin on concanavalin A (ConA)-induced acute fulminant hepatitis and the underlying mechanism. Mice were injected with ConA (25 mg/kg) to induce acute fulminant hepatitis, three doses of isorhamnetin (10/30/90 mg/kg) was intraperitoneally administrated about 1 h previously. The serum and liver tissues were harvested at 2, 8, and 24 h after ConA injection. The levels of serum liver enzymes and proinflammatory cytokines were significantly reduced in isorhamnetin administration groups. Besides, isorhamnetin improved pathological damage. Furthermore, isorhamnetin affected P38/PPAR-α pathway, and subsequently regulated the expression of apoptosis and autophagy related proteins. The present study investigated that isorhamnetin inhibits apoptosis and autophagy via P38/PPAR-α pathway in mice.

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.

The Hepatoprotection by Oleanolic Acid Preconditioning: Focusing on PPARα Activation

Objective

Previous studies have characterized the hepatoprotective and anti-inflammatory properties of oleanolic acid (OA). This study aimed to investigate the molecular mechanisms of OA hepatoprotection in concanavalin A- (ConA-) induced acute liver injury.

Materials and Methods

ConA (20 mg/kg) was intravenously injected to induce acute liver injury in Balb/C mice. OA pretreatment (20, 40, and 80 mg/kg) was administered subcutaneously once daily for 3 consecutive days prior to treatment with ConA; 2, 8, and 24 h after ConA injection, the levels of serum liver enzymes and the histopathology of major factors and inflammatory cytokines were determined.

Results

OA reduced the release of serum liver enzymes and inflammatory factors and prevented ConA mediated damage to the liver. OA elevated the expression levels of peroxisome proliferator-activated receptor alpha (PPARα) and decreased the phosphorylation of c-Jun NH2-terminal kinase (JNK).

Conclusion

OA exhibits anti-inflammatory properties during ConA-induced acute liver injury by attenuating apoptosis and autophagy through activation of PPARα and downregulation of JNK signaling.

Polyguluronate sulfate (PGS) attenuates immunological liver injury in vitro and in vivo

Hepatocyte damage, especially immunological liver injury, is a key process in the pathogenesis of hepatitis virus-induced liver diseases. The aim of this study was to investigate the protective effects of polyguluronate sulfate (PGS) against immunological liver damage. The results showed that PGS significantly reduced the H₂O₂-induced oxidative stress and increased the cell viability in HepG2 hepatocytes. PGS also suppressed the production of malondialdehyde (MDA), lactate dehydrogenase (LDH), TNF-α, and IL-6, while up-regulating the activity of SOD in HepG2 cells. Further, PGS (150 and 300mg/kg/day) significantly attenuated the elevation of serum glutamate pyruvate transaminase (ALT), aspartate aminotransferase (AST), total bilirubin (TBiL), in addition to liver MDA and NO levels in Con A-induced immunological liver injury within mice (P<0.05). Significant improvements of organ indexes (liver, spleen, and thymus) were observed in PGS-treated mice. PGS also significantly reduced the disorganization of hepatocytes and decreased the inflammatory cell infiltration caused by Con A treatment, suggesting that PGS was able to attenuate Con A-induced liver injury. In conclusion, PGS possesses significant hepatoprotective effects on immunological liver injury in vitro and in vivo, and this may be related to its antioxidant activities.

Salidroside ameliorates autophagy and activation of hepatic stellate cells in mice via NF-κB and TGF-β1/Smad3 pathways

PURPOSE

Liver fibrosis is commonly seen and a necessary stage in chronic liver disease. The aim of this study was to explore the effect of salidroside on liver fibrosis in mice and its potential mechanisms.

MATERIALS AND METHODS

Two mouse liver fibrosis models were established by intraperitoneal injection of carbon tetrachloride (CCl₄) for 8 weeks and bile duct ligation for 14 days. Salidroside was injected intraperitoneally at doses of 10 and 20 mg/kg once a day. Gene and protein expression levels were determined by quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, Western blot, immunohistochemistry, and immunofluorescence.

RESULTS

Salidroside inhibited the production of extracellular matrix (ECM) and regulated the balance between MMP2 and TIMP1 and, therefore, alleviated liver fibrosis in the two fibrosis models. Salidroside reduced the production of transforming growth factor (TGF)-β1 in Kupffer cells and hepatic stellate cells (HSCs) via the nuclear factor-κB signaling pathway and, therefore, inhibited the activation of HSCs and autophagy by downregulation of the TGF-β1/Smad3 signaling pathway.

CONCLUSION

Salidroside can effectively attenuate liver fibrosis by inhibiting the activation of HSCs in mice.

The liver protection of propylene glycol alginate sodium sulfate preconditioning against ischemia reperfusion injury: focusing MAPK pathway activity

Hepatic ischemia reperfusion (IR) injury contributes to the morbidity and mortality associated with liver surgery. This study investigated the protective function and mechanism of propylene glycol alginate sodium sulfate (PSS), a sulfated polysaccharide, in a mouse hepatic IR injury model. PSS (25 or 50 mg/kg) or saline were injected intraperitoneally to male Balb/c mice 1 h before 45 min of 70% warm hepatic ischemia and 2, 8, and 24 h of reperfusion. Serum and liver tissue samples were collected for evaluation of hepatocellular damage, liver histology, and assay of inflammatory cytokines, apoptosis- and autophagy-related proteins, and proteins in the mitogen-activated protein kinase (MAPKs). Histological injury and release of transaminases, and inflammatory cytokine production were significantly reduced by PSS pretreatment. The expression of apoptosis- and autophagy-related proteins, and the activation of MAPK signal, including jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and P38 were all affected by PSS treatment compared with IR model controls. PSS protected the liver from IR injury by suppressing the MAPK signaling and down-regulating inflammation, apoptosis, and autophagy.