Ampelopsin attenuates carbon tetrachloride-induced mouse liver fibrosis and hepatic stellate cell activation associated with the SIRT1/TGF-β1/Smad3 and autophagy pathway

Advances in Research on the Effectiveness and Mechanism of Active Ingredients from Traditional Chinese Medicine in Regulating Hepatic Stellate Cells Autophagy Against Hepatic Fibrosis

Hepatic fibrosis (HF) is a pathological process of structural and functional impairment of the liver and is a key component in the progression of chronic liver disease. There are no specific anti-hepatic fibrosis (anti-HF) drugs, and HF can only be improved or prevented by alleviating the cause. Autophagy of hepatic stellate cells (HSCs) is closely related to the development of HF. In recent years, traditional Chinese medicine (TCM) has achieved good therapeutic effects in the prevention and treatment of HF. Several active ingredients from TCM (AITCM) can regulate autophagy in HSCs to exert anti-HF effects through different pathways, but relevant reviews are lacking. This paper reviewed the research progress of AITCM regulating HSCs autophagy against HF, and also discussed the relationship between HSCs autophagy and HF, pointing out the problems and limitations of the current study, in order to provide references for the development of anti-HF drugs targeting HSCs autophagy in TCM. By reviewing the literature in PubMed, Web of Science, Embase, CNKI and other databases, we found that the relationship between autophagy of HSCs and HF is currently controversial. HSCs autophagy may promote HF by consuming lipid droplets (LDs) to provide energy for their activation. However, in contrast, inducing autophagy in HSCs can exert the anti-HF effect by stimulating their apoptosis or senescence, reducing type I collagen accumulation, inhibiting the extracellular vesicles release, degrading pro-fibrotic factors and other mechanisms. Some AITCM inhibit HSCs autophagy to resist HF, with the most promising direction being to target LDs. While, others induce HSCs autophagy to resist HF, with the most promising direction being to target HSCs apoptosis. Future research needs to focus on cell targeting research, autophagy targeting research and in vivo verification research, and to explore the reasons for the contradictory effects of HSCs autophagy on HF.

Plant-derived flavonoids are a potential source of drugs for the treatment of liver fibrosis

Liver fibrosis is a dynamic pathological process that can be triggered by any chronic liver injury. If left unaddressed, it will inevitably progress to the severe outcomes of liver cirrhosis or even hepatocellular carcinoma. In the past few years, the prevalence and fatality of hepatic fibrosis have been steadily rising on a global scale. As a result of its intricate pathogenesis, the quest for pharmacological interventions targeting liver fibrosis has remained a formidable challenge. Currently, no pharmaceuticals are exhibiting substantial clinical efficacy in the management of hepatic fibrosis. Hence, it is of utmost importance to expedite the development of novel therapeutics for the treatment of this condition. Various research studies have revealed the ability of different natural flavonoid compounds to alleviate or reverse hepatic fibrosis through a range of mechanisms, which are related to the regulation of liver inflammation, oxidative stress, synthesis and secretion of fibrosis-related factors, hepatic stellate cells activation, and proliferation, and extracellular matrix synthesis and degradation by these compounds. This review summarizes the progress of research on different sources of natural flavonoids with inhibitory effects on liver fibrosis over the last decades. The anti-fibrotic effects of natural flavonoids have been increasingly studied, making them a potential source of drugs for the treatment of liver fibrosis due to their good efficacy and biosafety.

Therapeutic potential of natural products in schistosomiasis-associated liver fibrosis

Schistosomiasis is a parasitic disease that endangers human health and social development. The granulomatous reaction of Schistosoma eggs in the liver is the main cause of hepatosplenomegaly and fibrotic lesions. Anti liver fibrosis therapy is crucial for patients with chronic schistosomiasis. Although Praziquantel is the only clinical drug used, it is limited in insecticide treatment and has a long-term large-scale use, which is forcing the search for cost-effective alternatives. Previous research has demonstrated that plant metabolites and extracts have effective therapeutic effects on liver fibrosis associated with schistosomiasis. This paper summarizes the mechanisms of action of metabolites and some plant extracts in alleviating schistosomiasis-associated liver fibrosis. The analysis was conducted using databases such as PubMed, Google Scholar, and China National Knowledge Infrastructure (CNKI) databases. Some plant metabolites and extracts ameliorate liver fibrosis by targeting multiple signaling pathways, including reducing inflammatory infiltration, oxidative stress, inhibiting alternate macrophage activation, suppressing hepatic stellate cell activation, and reducing worm egg load. Natural products improve liver fibrosis associated with schistosomiasis, but further research is needed to elucidate the effectiveness of natural products in treating liver fibrosis caused by schistosomiasis, as there is no reported data from clinical trials in the literature.

The role of sirtuin1 in liver injury: molecular mechanisms and novel therapeutic target

Liver disease is a common and serious threat to human health. The progression of liver diseases is influenced by many physiologic processes, including oxidative stress, inflammation, bile acid metabolism, and autophagy. Various factors lead to the dysfunction of these processes and basing on the different pathogeny, pathology, clinical manifestation, and pathogenesis, liver diseases are grouped into different categories. Specifically, Sirtuin1 (SIRT1), a member of the sirtuin protein family, has been extensively studied in the context of liver injury in recent years and are confirmed the significant role in liver disease. SIRT1 has been found to play a critical role in regulating key processes in liver injury. Further, SIRT1 seems to cause divers outcomes in different types of liver diseases. Recent studies have showed some therapeutic strategies involving modulating SIRT1, which may bring a novel therapeutic target. To elucidate the mechanisms underlying the role of sirtuin1 in liver injury and its potentiality as a therapeutic target, this review outlines the key signaling pathways associated with sirtuin1 and liver injury, and discusses recent advances in therapeutic strategies targeting sirtuin1 in liver diseases.

Mechanisms of the TGF-β1/Smad3-signaling pathway in gender differences in alcoholic liver fibrosis

The TGF-β1/Smad3-signaling pathway and gender differences were investigated in alcoholic liver fibrosis. Mice were divided into female normal, female model, male normal, and male model groups. Liver injury and fibrosis were assessed using histopathology and serology. Western blotting was performed to analyze the expression of relevant factors. HSC-T6 cells were divided into estradiol + saline, estradiol + ethanol, testosterone + saline, and testosterone + ethanol groups, and similar assessments were conducted in vitro. Compared with the female model group, the male model group exhibited significantly increased GPT, GOT, TNF-α, IL-6, and testosterone levels, fibrosis rate, and TGF-β1, Smad3, and PCNA expression, and significantly decreased estradiol levels and Caspase-3 expression. The apoptosis rate was higher in the estradiol + ethanol group than in the testosterone + ethanol group, although the testosterone + ethanol group exhibited significantly increased TNF-α, IL-6, Collagen-I, α-SMA, TGF-β1, Smad3, and PCNA expression, and significantly decreased Caspase-3 expression. Alcoholic liver fibrosis showed significant gender differences associated with the TGF-β1/Smad3-signaling pathway.

Chemical Constituents and α-Glucosidase Inhibitory, Antioxidant and Hepatoprotective Activities of Ampelopsis grossedentata

Ampelopsis grossedentata is a valuable medicinal and edible plant, which is often used as a traditional tea by the Tujia people in China. A. grossedentata has numerous biological activities and is now widely used in the pharmaceutical and food industries. In this study, two new flavonoids (1-2) and seventeen known compounds (3-19) were isolated and identified from the dried stems and leaves of A. grossedentata. These isolated compounds were characterized by various spectroscopic data including mass spectrometry and nuclear magnetic resonance spectroscopy. All isolates were assessed for their α-glucosidase inhibitory, antioxidant, and hepatoprotective activities, and their structure-activity relationships were further discussed. The results indicated that compound 1 exhibited effective inhibitory activity against α-glucosidase, with an IC50 value of 0.21 μM. In addition, compounds 1-2 demonstrated not only potent antioxidant activities but also superior hepatoprotective properties. The findings of this study could serve as a reference for the development of A. grossedentata-derived products or drugs aimed at realizing their antidiabetic, antioxidant, and hepatoprotective functions.

A comprehensive review of vine tea: Origin, research on Materia Medica, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Vine tea is a popular folk tea that has been consumed in China for more than 1200 years. It is often used in ethnic medicine by ethnic groups in southwest China with at least 35 aliases in 10 provinces. In coastal areas, vine tea is mostly used to treat heatstroke, aphtha, aphonia, toothache, etc. In contrast, in the southwest inland regions, vine tea is mostly used to clear away heat and toxic materials, antiphlogosis and relieving sore-throat, lowering blood pressure and lipid levels, and alleviating fatigue. Three main species have been used as the source of vine tea, Nekemias grossedentata, Nekemias cantonensis and Nekemias megalophylla. Among them, the leaves of Nekemias grossedentata were considered as new food resource in complicance with regulations, according to the Food Safety Standards published by the Monitoring and Evaluation Department of the National Health and Family Planning Commission in China.

AIM OF THE STUDY

At present, the comprehensively summary of Materia Medica on the history and source of vine tea is currently unavailable. The current article summed up the Materia Medica, species origin and pharmacological effects of all 3 major species used in vine tea to fill the knowledge gaps. We also aim to provide a reference for future research on historical textual, resource development and medicinal utilization of vine tea.

MATERIALS AND METHODS

Adhering to the literature screening methodology outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), this review encompasses 148 scholarly research papers from three database, paper ancient books, local chronicles and folklore through field investigations. We then comprehensively summarized and discussed research progresses in scientific and application studies of vine tea.

RESULTS

The historical records indicated that vine tea could have been used as early as Southern and Northern Dynasties (AC 420-589). Nekemias grossedentata, Nekemias cantonensis and Nekemias megalophylla, were used to considered as vine tea in the ethnic medicine. The main phytochemicals found in three plants are flavonoids, polyphenols and terpenoids, among which dihydromyricetin (DHM) is the most important and most studied active substance. The key words "Ampelopsis grossedentata" (Synonym of Nekemias grossedentata) and "dihydromyricetin/DHM" showed the highest frequency over the last 27 year based on the research trend analysis. And the ethnopharmacology studies drawn the main activities of vine tea are antioxidant, antibacterial, hepatoprotective, neuroprotective and anti-atherosclerosis activities.

CONCLUSIONS

This review systematically summarized and discussed vine tea from the following five aspects, history, genetic relationship, phytochemistry, research trend and ethnopharmacology. Vine tea has a long historical usage in Chinese ethnic medicine. Its outstanding therapeutic efficacies have attracted extensive attention in other places in the world at present. Nekemias cantonensis and Nekemias megalophylla are quite similar to Nekemias grossedentata in terms of many aspects. However, the current research has a narrow focus on mainly Nekemias grossedentata and DHM. We propose that future studies could be carried out to determine the synergistic effect of multi-components and multi-targets of vine tea including all 3 species to provide valuable knowledge.

HSC-derived exosomal miR-199a-5p promotes HSC activation and hepatocyte EMT via targeting SIRT1 in hepatic fibrosis

Exosomes have been implicated in inflammation-related diseases, such as hepatic fibrosis (HF) and renal fibrosis, via transferring bioactive cargoes to recipient cells. This study aimed to investigate the possible effect of hepatic stellate cell (HSC)-derived exosomes on the initiation and development of HF by delivering microRNA (miR)-199a-5p. In HF rats with cholestasis induced by ligating the common bile duct, miR-199a-5p was upregulated while SIRT1 was downregulated in liver tissues from bile duct ligation (BDL) rats compared with that of sham rats. Furthermore, miR-199a-5p expression was upregulated, but the mRNA and protein expression levels of SIRT1 were downregulated in TGF-β1-activated LX-2. miR-199a-5p promoted the proliferation and further activation of LX-2 and enhanced the expression levels of the HF markers COL1A1 and α-SMA. Subsequently, the binding of miR-199a-5p to the 3'UTR of SIRT1 mRNA was predicted by bioinformatics websites and evidenced by fluorescent reporter assay. Knocking down SIRT1 enhanced the abilities of LX-2 cell proliferation, migration, and colony formation and increased the expression levels of the HF markers α-SMA and COL1A1. LX-2-derived exosomal miR-199a-5p transferred to LX-2 and THLE-2, inhibited the proliferation of THLE-2, and promoted the epithelial mesenchymal transition (EMT) and senescence of THLE-2. Furthermore, in vivo results suggested that miR-199a-5p overexpression aggravated HF in BDL rats; increased miR-199a-5p, α-SMA, and COL1A1 expression levels; and significantly upregulated the serum ALT, AST, TBA, and TBIL levels. However, reverse results were obtained with inhibited miR-199a-5p expression. In conclusion, HSC-derived exosomal miR-199a-5p may promote HF by accelerating HSC activation and hepatocyte EMT by targeting SIRT1, suggesting that miR-199a-5p and SIRT1 may serve as potential therapeutic targets for HF.

Ferulic acid exerts a protective effect against cyclosporine-induced liver injury in rats via activation of the Nrf2/HO-1 signaling, suppression of oxidative stress, inflammatory response, and halting the apoptotic cell death

Drug-induced liver injury is one of the main challenges that leads to the withdrawal of several drugs in the clinical setting. Cyclosporine is one of the drugs that its long-term administration exerts devastating effects on the hepatocytes. In the present study, we aimed to evaluate the effect of ferulic acid, a natural compound found in plants, on cyclosporine-mediated hepatotoxicity. Forty-eight male Wistar rats were treated with cyclosporine and/or ferulic acid to evaluate the function as well as the morphology of liver cells. We found that ferulic acid dose-dependently recovered the functional as well as histopathological parameters of liver cells, as revealed by the improvement of hepatocellular vacuolation, portal fibroplasia, and necrosis. Moreover, this phenolic compound was able to restore the balance of the redox system in cyclosporine-treated rats by activating the nuclear factor (NF) erythroid 2-related factor 2 (Nrf2)/hemeoxygenase-1 (HO-1) signaling axis. Of note, the protective effects of ferulic acid against cyclosporine-mediated liver toxicity were not restricted only to induction of the potential antioxidant property, as in the presence of this agent, the expression of pro-inflammatory cytokines such as NF-κB, tumor necrosis factor (TNF)-α, and interleukin-1β was also diminished. Ferulic acid also shifted the equilibrium between the expression levels of proapoptotic to antiapoptotic proteins and thereby prevented the development of cyclosporine-induced liver injury. Overall, these findings highlighted that ferulic acid can reduce cyclosporine-induced liver injury due to its antioxidant properties.

Fluorofenidone alleviates liver fibrosis by inhibiting hepatic stellate cell autophagy via the TGF-β1/Smad pathway: implications for liver cancer

Objectives

Liver fibrosis is a key stage in the progression of various chronic liver diseases to cirrhosis and liver cancer, but at present, there is no effective treatment. This study investigated the therapeutic effect of the new antifibrotic drug fluorofenidone (AKF-PD) on liver fibrosis and its related mechanism, providing implications for liver cancer.

Materials and Methods

The effects of AKF-PD on hepatic stellate cell (HSC) autophagy and extracellular matrix (ECM) expression were assessed in a carbon tetrachloride (CCl4)-induced rat liver fibrosis model. In vitro, HSC-T6 cells were transfected with Smad2 and Smad3 overexpression plasmids and treated with AKF-PD. The viability and number of autophagosomes in HSC-T6 cells were examined. The protein expression levels of Beclin-1, LC3 and P62 were examined by Western blotting. The Cancer Genome Atlas (TCGA) database was used for comprehensively analyzing the prognostic values of SMAD2 and SMAD3 in liver cancer. The correlation between SMAD2, SMAD3, and autophagy-related scores in liver cancer was explored. The drug prediction of autophagy-related scores in liver cancer was explored.

Results

AKF-PD attenuated liver injury and ECM deposition in the CCl4-induced liver fibrosis model. In vitro, the viability and number of autophagosomes in HSCs were reduced significantly by AKF-PD treatment. Meanwhile, the protein expression of FN, α-SMA, collagen III, Beclin-1 and LC3 was increased, and P62 was reduced by the overexpression of Smad2 and Smad3; however, AKF-PD reversed these effects. SMAD2 and SMAD3 were hazardous factors in liver cancer. SMAD2 and SMAD3 correlated with autophagy-related scores in liver cancer. Autophagy-related scores could predict drug response in liver cancer.

Conclusions

AKF-PD alleviates liver fibrosis by inhibiting HSC autophagy via the transforming growth factor (TGF)-β1/Smadpathway. Our study provided some implications about how liver fibrosis was connected with liver cancer by SMAD2/SMAD3 and autophagy.

Targeting extracellular matrix through phytochemicals: a promising approach of multi-step actions on the treatment and prevention of cancer

Extracellular matrix (ECM) plays a pivotal and dynamic role in the construction of tumor microenvironment (TME), becoming the focus in cancer research and treatment. Multiple cell signaling in ECM remodeling contribute to uncontrolled proliferation, metastasis, immune evasion and drug resistance of cancer. Targeting trilogy of ECM remodeling could be a new strategy during the early-, middle-, advanced-stages of cancer and overcoming drug resistance. Currently nearly 60% of the alternative anticancer drugs are derived from natural products or active ingredients or structural analogs isolated from plants. According to the characteristics of ECM, this manuscript proposes three phases of whole-process management of cancer, including prevention of cancer development in the early stage of cancer (Phase I); prevent the metastasis of tumor in the middle stage of cancer (Phase II); provide a novel method in the use of immunotherapy for advanced cancer (Phase III), and present novel insights on the contribution of natural products use as innovative strategies to exert anticancer effects by targeting components in ECM. Herein, we focus on trilogy of ECM remodeling and the interaction among ECM, cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs), and sort out the intervention effects of natural products on the ECM and related targets in the tumor progression, provide a reference for the development of new drugs against tumor metastasis and recurrence.

Sirt1 Overexpression Inhibits Fibrous Scar Formation and Improves Functional Recovery After Cerebral Ischemic Injury Through the Deacetylation of 14-3-3ζ

Cerebral ischemic stroke is one of the leading causes of human death. The fibrous scar is one of major factors influencing repair in central nervous system (CNS) injury. Silencing information regulator 2-related enzyme 1 (Sirt1) can regulate peripheral tissue and organ fibrosis. However, it is unclear how the fibrous scar forms and is regulated and it is unknown whether and how Sirt1 regulates the formation of the fibrous scar after cerebral ischemic stroke. Therefore, in the present study, we examined the effects of Sirt1 on the formation of the fibrotic scar after middle cerebral artery occlusion/reperfusion (MCAO/R) injury in vivo and on the transforming growth factor β1 (TGF-β1)-induced meningeal fibroblast fibrotic response in vitro, and we explored the molecular mechanisms underlying the Sirt1-regulated fibrosis process in vitro. We found that MCAO/R injury induced fibrotic scar formation in the ischemic area, which was accompanied by the downregulation of Sirt1 expression. The overexpression of Sirt1 reduced the infarct volume, improved Nissl body structure and reduced neurons injury, attenuated formation of fibrotic scar, upregulated growth associated protein43 (GAP43) and synaptophysin (SYP) expression, and promoted neurological function recovery. Similarly, Sirt1 expression was also downregulated in the TGF-β1-induced fibrosis model. Sirt1 overexpression inhibited fibroblast migration, proliferation, transdifferentiation into myofibroblasts, and secretion of extracellular matrix(ECM) by regulating the deacetylation of lysine at K49 and K120 sites of 14-3-3ζ in vitro. Therefore, we believe that Sirt1 could regulate fibrous scar formation and improve neurological function after cerebral ischemic stroke through regulating deacetylation of 14-3-3ζ.

Regulation of SIRT1-TLR2/TLR4 pathway in cell communication from macrophages to hepatic stellate cells contribute to alleviates hepatic fibrosis by Luteoloside

Regulating macrophage-hepatic stellate cells (HSCs) crosstalk through SIRT1-TLR2/TLR4 has contributed to the essence of new pharmacologic strategies to improve hepatic fibrosis. We investigated how Luteoloside (LUT), one of the flavonoid monomers isolated from Eclipta prostrata (L.) L., modulates macrophage-HSCs crosstalk during hepatic fibrosis. HSC-T6 or rat peritoneal macrophages were activated by TGF-β or LPS/ATP, and then treated with LUT or Sirtinol (SIRT1 inhibitor) for 6 h. Further, HSCs were cultured with the conditioned medium from the LPS/ATP activated peritoneal macrophages. In HSC-T6 or peritoneal macrophages, LUT could decrease the expressions of α-SMA, Collagen-I, the ratio of TIMP-1/MMP-13. LUT also significantly increased the expressions of SIRT1 and ERRα. And LUT significantly suppressed the releases of pro-inflammatory cytokines, including NLRP3, ASC, caspase-1, IL-1β, and regulated signaling TLR2/TLR4-MyD88 activation. The expressions of TLR2, TLR4, NLRP3, caspase-1, IL-1β, α-SMA were increased and the expression of ERRα was decreased by Sirtinol, indicated that LUT might mediate SIRT1 to regulate TLR4 expression and further alleviate inflammation and fibrosis. LUT could regulate SIRT1-mediated TLR4 and ECM in HSCs was reduced, when HSCs were cultured with conditioned medium. Hence, LUT could decrease the expressions of fibrosis markers, reduce the releases of inflammatory cytokines in activated HSCs or macrophages. In conclusion, LUT might be a promising candidate that regulating SIRT1-TLR2/TLR4 signaling in macrophages interacting with HSCs during hepatic fibrosis.

Strategic developments in the drug delivery of natural product dihydromyricetin: applications, prospects, and challenges

Dihydromyricetin (DHM) is an important natural flavonoid that has attracted much attention because of its various functions such as protecting the cardiovascular system and liver, treating cancer and neurodegenerative diseases, and anti-inflammation effect, etc. Despite its great development potential in pharmacy, DHM has some problems in pharmaceutical applications such as low solubility, permeability, and stability. To settle these issues, extensive research has been carried out on its physicochemical properties and dosage forms to produce all kinds of DHM preparations in the past ten years. In addition, the combined use of DHM with other drugs is a promising strategy to expand the application of DHM. However, although invention patents for DHM preparations have been issued in several countries, the current transformation of DHM research results into market products is insufficient. To date, there is still a lack of deep research into the pharmacokinetics, pharmacodynamics, toxicology, and action mechanism of DHM preparations. Besides, preparations for combined therapy of DHM with other drugs are scarcely reported, which necessitates the development of dosage forms for this application. Apart from medicine, the development of DHM in the food industry is also of great potential. Due to its multiple effects and excellent safety, DHM preparations can be developed for functional drinks and foods. Through this review, we hope to draw more attention to the development potential of DHM and the above challenges and provide valuable references for the research and development of other natural products with a similar structure-activity relationship to this drug.

A, Venkidasamy B, Cespedes-Acuna CL, Nile SH, Yan G, Zheng H. Pien-Tze-Huang alleviates CCl4-induced liver fibrosis through the inhibition of HSC autophagy and the TGF-β1/Smad2 pathway

Ethnopharmacological relevance: Pien-Tze-Huang (PZH)—a traditional Chinese medicine (TCM) compound—has been employed to treat various liver inflammation and tumors for over 10 decades. Interestingly, most of the pharmacological effects had been validated and explored toward liver ailment along with pro-inflammatory conditions and cancer at the cellular and molecular level to date.

Aim of the study: The present study aimed to investigate the therapeutic effect of PZH on autophagy and TGF-β1 signaling pathways in rats with liver fibrosis and hepatic stellate cell line (HSC).

Materials and methods: Male SD rats with carbon tetrachloride (CCl4)-induced liver fibrosis were used as the animal model. Next, PZH treatment was given for 8 weeks. Afterward, the therapeutic effects of PZH were analyzed through a hepatic tissue structure by hematoxylin-eosin (H&E), Van Gieson (VG) staining, and transmission electron microscopy (TEM), activity of ALT and AST by enzyme-associated immunosorbent assay as well. Subsequently, mRNA and protein expression were examined by quantitative polymerase chain reaction (qPCR), Western blotting, and immunohistochemistry (IHC). Then, the cell vitality of PZH-treated HSC and the expression of key molecules prevailing to autophagy were studied in vitro. Meanwhile, SM16 (a novel small molecular inhibitor which inhibits TGFβ-induced Smad2 phosphorylation) was employed to confirm PZH’s effects on the proliferation and autophagy of HSC.

Results: PZH pharmacologically exerted anti-hepatic fibrosis effects as demonstrated by protecting hepatocytes and improving hepatic function. The results revealed the reduced production of extracellular collagen by adjusting the balance of matrix metalloproteinase (MMP) 2, MMP9, and tissue inhibitor of matrix metalloproteinase 1 (TIMP1) in PZH-treated CCl4-induced liver fibrosis. Interestingly, PZH inhibited the activation of HSC by down-regulating TGF-β1 and phosphorylating Smad2. Furthermore, PZH down-regulated yeast Atg6 (Beclin-1) and microtubule-associated protein light chain 3 (LC3) toward suppressing HSC autophagy, and PZH exhibited similar effects to that of SM16.

Conclusion: To conclude, PZH alleviated CCl4-induced liver fibrosis to reduce the production of extracellular collagen and inhibiting the activation of HSC. In addition, their pharmacological mechanisms related to autophagy and TGF-β1/Smad2 signaling pathways were revealed for the first time.

Implication of autophagy in the antifibrogenic effect of Rilpivirine: when more is less

As the main extracellular matrix-producing cells, activated hepatic stellate cells (HSC) are fundamental mediators of liver fibrosis (LF), and understanding their activation/inactivation mechanisms is paramount to the search for novel therapeutics. The antiretroviral drug Rilpivirine (RPV) has demonstrated a hepatoprotective effect in several animal models of chronic liver injury that is related to its antifibrogenic and apoptotic action in HSC. In the present study, we evaluated whether autophagy is implicated in the hepatoprotective action of RPV, as autophagy plays an important role in HSC transdifferentiation. We employed two standard mouse models of chronic liver injury - fatty liver disease and carbon tetrachloride (CCl₄)-induced hepatotoxicity -and cultured HSC activated with the profibrotic cytokine TGF-β. RPV enhanced autophagy in the whole liver of both mouse models and in activated HSC, evident in the protein expression of autophagy markers, increased autophagosome content and lysosomal mass. Moreover, increased autophagic flux was observed in RPV-exposed HSC as revealed by tandem fluorescence-tagged LC3 and p62 and analysis of LC3-II accumulation in cells exposed to the lysosomal inhibitor chloroquine. Importantly, autophagy was involved in the cytotoxic effect of RPV on HSC, though in a differential manner. Pharmacological inhibition of autophagy by 3-methyladenine (3-MA) did not affect the diminishing effect of RPV on viability, while treatment with wortmannin or depletion of specific autophagy proteins (ATG5, Beclin-1 and SQSTM1/p62) rescued the detrimental effect of high concentrations of RPV on the viability of activated HSC. Finally, we also provide evidence that RPV compromises the viability of TGF-β-induced HSC independently of its antifibrogenic effect, observed as reduced collagen 1A1 synthesis, and that this effect does not include RPV´s modulation of autophagy. In summary, as a contributor to the mechanisms involved in the hepatoprotective action of RPV, autophagy may be a good candidate to explore when developing novel therapeutics for LF.

Ginsenoside Rg2 Ameliorating CDAHFD-Induced Hepatic Fibrosis by Regulating AKT/mTOR-Mediated Autophagy

Ginsenoside Rg2 (G-Rg2) in the rhizome of Panax ginseng can modify lipid accumulation, oxidative stress, and apoptosis in the liver induced by a high-fat diet. This research adds to this by assessing the potential antifibrosis effect of G-Rg2 (including possible mechanisms). G-Rg2 significantly improved pathological changes in liver tissue induced by a choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD), it inhibited serum transaminase, plasma lipopolysaccharide, and liver hydroxyproline levels; it inhibited TGF-β1, α-SMA, and COL1A1 expression, it activated the AKT/mTOR signal pathway, and it inhibited liver expression of autophagy-related proteins. The in vitro experiments showed that G-Rg2 also restored the autophagy flux impairment induced by oleic acid and inhibited TGF-β1 expression by promoting p62 degradation in hepatocytes. In hepatic stellate (HSC-T6) cells, G-Rg2 reversed lipopolysaccharide-induced activation through the AKT/mTOR signaling pathway, inhibiting autophagy. Thus, G-Rg2 ameliorates CDAHFD-induced liver fibrosis and lipopolysaccharide-induced HSC-T6 cell activation by inhibiting AKT/mTOR-mediated autophagy.

Sec62 promotes gastric cancer metastasis through mediating UPR-induced autophagy activation

BACKGROUND AND AIMS

Sec62 is a membrane protein of the endoplasmic reticulum that facilitates protein transport. Its role in cancer is increasingly recognised, but remains largely unknown. We investigated the functional role of Sec62 in gastric cancer (GC) and its underlying mechanism.

METHODS

Bioinformatics, tissue microarray, immunohistochemistry (IHC), western blotting (WB), quantitative polymerase chain reaction (qPCR), and immunofluorescence were used to examine the expression of target genes. Transwell, scratch healing assays, and xenograft models were used to evaluate cell migration and invasion. Transmission electron microscopy and mRFP-GFP-LC3 double-labeled adenoviruses were used to monitor autophagy. Co-immunoprecipitation (CO-IP) was performed to evaluate the binding activity between the proteins.

RESULTS

Sec62 expression was upregulated in GC, and Sec62 upregulation was an independent predictor of poor prognosis. Sec62 overexpression promoted GC cell migration and invasion both in vitro and in vivo. Sec62 promoted migration and invasion by affecting TIMP-1 and MMP2/9 balance. Moreover, Sec62 could activate autophagy by upregulating PERK/ATF4 expression and binding to LC3II with concomitant FIP200/Beclin-1/Atg5 activation. Furthermore, autophagy blockage impaired the promotive effects of Sec62 on GC cell migration and invasion, whereas autophagy activation rescued the inhibitory effect of Sec62 knockdown on GC metastasis. Notably, Sec62 inhibition combined with autophagy blockage exerted a synergetic anti-metastatic effect in vitro and in vivo.

CONCLUSION

Sec62 promotes GC metastasis by activating autophagy and subsequently regulating TIMP-1 and MMP2/9 balance. The activation of autophagy by Sec62 may involve the unfolded protein response (UPR)-related PERK/ATF4 pathway and binding of LC3II during UPR recovery involving FIP200/Beclin-1/Atg5 upregulation. Specifically, the dual inhibition of Sec62 and autophagy may provide a promising therapeutic strategy for GC metastasis.

Total astragalosides decrease apoptosis and pyroptosis by inhibiting enterovirus 71 replication in gastric epithelial cells

Enterovirus 71 (EV71) is one of the primary pathogens involved in severe hand, foot and mouth disease in children. EV71 infection causes various types of programmed cell death. However, there are currently no clinically approved specific antiviral drugs for control of EV71 infection. Astragalus membranaceus (AM), a Traditional Chinese medicine, has been used in antiviral therapy in China. The aim of the present study was to determine whether total astragalosides (ASTs), bioactive components of AM, protect against EV. DAPI nuclear staining was used to observe morphological changes of the nucleus and the protective effect of ASTs, which revealed that the nucleus shrank following EV71 infection, while ASTs reversed it. Cell Counting Kit-8 assay found that human normal gastric epithelial cell (GES-1 cell) viability decreased following EV71 infection, while lactate dehydrogenase (LDH) assay showed that EV71 infection induced GES-1 cell damage. Western blotting was used to measure the expression levels of apoptosis and pyroptosis marker protein to determine whether EV71 infection induced apoptosis and pyroptosis in GES-1 cells. Reverse transcription-quantitative PCR was used to determine the anti-EV71 effect of ASTs. The results showed that ASTs protected GES-1 cells from EV71-induced cell apoptosis and pyroptosis. Furthermore, the present data demonstrated that the protective effect of ASTs was exerted by suppressing EV71 replication and release. These findings suggested that ASTs may represent a potential antiviral agent for the treatment of EV71 infection.

Sirtuins at the Service of Healthy Longevity

Sirtuins may counteract at least six hallmarks of organismal aging: neurodegeneration, chronic but ineffective inflammatory response, metabolic syndrome, DNA damage, genome instability, and cancer incidence. Moreover, caloric restriction is believed to slow down aging by boosting the activity of some sirtuins through activating adenosine monophosphate-activated protein kinase (AMPK), thus raising the level of intracellular nicotinamide adenine dinucleotide (NAD⁺) by stimulating NAD⁺ biosynthesis. Sirtuins and their downstream effectors induce intracellular signaling pathways related to a moderate caloric restriction within cells, mitigating reactive oxygen species (ROS) production, cell senescence phenotype (CSP) induction, and apoptosis as forms of the cellular stress response. Instead, it can promote DNA damage repair and survival of cells with normal, completely functional phenotypes. In this review, we discuss mechanisms of sirtuins action toward cell-conserving phenotype associated with intracellular signaling pathways related to moderate caloric restriction, as well as some tissue-specific functions of sirtuins, especially in the central nervous system, heart muscle, skeletal muscles, liver, kidneys, white adipose tissue, hematopoietic system, and immune system. In this context, we discuss the possibility of new therapeutic approaches.

Ubiquitin pathways regulate the pathogenesis of chronic liver disease

Chronic liver disease (CLD) is considered the leading cause of global mortality. In westernized countries, increased consumption of alcohol and overeating foods with high fat/ high glucose promote progression of CLD such as alcoholic liver disease (ALD) and non-alcoholic liver disease (NAFLD). Accumulating evidence and research suggest that ubiquitin, a 75 amino acid protein, plays crucial role in the pathogenesis of CLD through dynamic post-translational modifications (PTMs) exerting diverse cellular outcomes such as protein degradation through ubiquitin-proteasome system (UPS) and autophagy, and regulation of signal transduction. In this review, we present the function of ubiquitination and latest findings on diverse mechanism of PTMs, UPS and autophagy which significantly contribute to the pathogenesis of alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), cirrhosis, and HCC. Despite its high prevalence, morbidity, and mortality, there are only few FDA approved drugs that could be administered to CLD patients. The goal of this review is to present a variety of pathways and therapeutic targets involving ubiquitination in the pathogenesis of CLD. Further, this review summarizes collective views of pharmaceutical inhibition or activation of recent drugs targeting UPS and autophagy system to highlight potential targets and new approaches to treat CLD.

Puerarin Attenuates Complete Freund's Adjuvant-Induced Trigeminal Neuralgia and Inflammation in a Mouse Model via Sirt1-Mediated TGF-β1/Smad3 Inhibition

Background

Puerarin, an active compound of radix puerariae, is a major compound used in Chinese herbal medicines and it has been well known for its pharmacological effects, including antioxidant, anti‑inflammatory, neuroprotective and cardioprotective properties. The aim of the present study was to determine the role of puerarin (Pue) in complete Freund’s adjuvant (CFA)-induced trigeminal neuralgia (TN) and the effects of this compound on Sirt1 activity and on the progression of CFA-induced TN.

Methods

Mice were injected with CFA on the unilateral face to induce TN. A cell model of inflammation-associated TN was established by interleukin-1β (IL-1β; 10 ng/mL) and tumor necrosis factor-α (TNF-α; 50 ng/mL) stimulation of neurons. Reverse transcription-quantitative PCR and Western blot analyses were performed to analyze mRNA and protein expression levels in trigeminal ganglion and nerve cells. Terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining was used to determine nerve cell apoptosis following IL-1β/TNF-α or Pue treatment.

Results

Pue is a conceivable Sirtuin1 (Sirt1) activator used for the prevention of trigeminal nerve injury that attenuates CFA-induced TN and inflammatory cytokine-evoked overactivation of neuronal inflammation and apoptosis. Treatment of mice with inflammatory cytokines induced upregulation of cleaved caspase-3 protein expression, which was neutralized by Pue supplementation. Both in vivo and in vitro experiments led to the conclusion that Pue modulated Sirt1 activation and repressed transforming growth factor-β1 (TGF-β1) protein expression and drosophila mothers against decapentaplegic homolog3 (Smad3) phosphorylation in order to exert neuroprotection.

Conclusion

The findings suggested that Pue functioned as a potential Sirt1 activator to improve neuroinflammation-induced TN and neuronal apoptosis via the suppression of TGF-β1/Smad3 activity. The pharmacological activity of Pue provides a new perspective for the effective prevention and treatment of TN.

Anti-oxidant, anti-inflammatory and anti-fibrosis effects of ganoderic acid A on carbon tetrachloride induced nephrotoxicity by regulating the Trx/TrxR and JAK/ROCK pathway

Ganoderic acid A (GAA), one of the major triterpenoid components extracted from Ganoderma mushroom has been shown to possess numerous important pharmacological activities. The present study was aimed to investigate the mechanisms of GAA on carbon tetrachloride (CCl4)-induced kidney inflammation, fibrosis and oxidative stress in mice. The male mice were treated with 25 and 50 mg/mg GAA after stimulated with CCl4. Our results showed that GAA improved renal damage by decreasing the serum levels of creatinine, urea, uric acid and alleviating kidney fibrosis. GAA ameliorated CCl4-induced indices of inflammation. GAA suppressed oxidative stress by regulating the glutathione antioxidant system and the thioredoxin antioxidant system. GAA increased the activations of thioredoxin reductase (TrxR), Trx, GSH, SOD, GPx. Furthermore, GAA supplementation inhibited the JAK and STAT3 pathway. GAA inhibited the activations of RhoA, ROCK, NF-κB, TGF-β and Smad3. Thus, this study demonstrated that GAA possesses immune-protective properties through regulating the Trx/TrxR, JAK2/STAT3 and RhoA/ROCK pathways.

Molecular mechanisms and therapeutic implications of dihydromyricetin in liver disease

Recent studies demonstrated that dihydromyricetin (DHM) has prominent therapeutic effects on liver injury and liver cancer. By summarizing the current preclinical in vitro and in vivo studies, the present review examines the preventive and therapeutic effects of DHM on liver disorders as well as its potential mechanisms. Briefly, in both chemical- and alcohol-induced liver injury models, DHM ameliorates hepatocyte necrosis and steatosis while promoting liver regeneration. In addition, DHM can alleviate nonalcoholic fatty liver disease (NAFLD) via regulating lipid/glucose metabolism, probably due to its anti-inflammatory or sirtuins-dependent mechanisms. Furthermore, DHM treatment inhibits cell proliferation, induces apoptosis and autophagy and regulates redox balance in liver cancer cells, thus exhibiting remarkable anti-cancer effects. The pharmacological mechanisms of DHM may be associated with its anti-inflammatory, anti-oxidative and apoptosis-regulatory benefits. With the accumulating interests in utilizing natural products to target common diseases, our work aims to improve the understanding of DHM acting as a novel drug candidate for liver diseases and to accelerate its translation from bench to bedside.

Understanding the implication of autophagy in the activation of hepatic stellate cells in liver fibrosis: are we there yet?

Liver fibrosis (LF) occurs as a result of persistent liver injury and can be defined as a pathologic, chronic, wound-healing process in which functional parenchyma is progressively replaced by fibrotic tissue. As a phenomenon involved in the majority of chronic liver diseases, and therefore prevalent, it exerts a significant impact on public health. This impact becomes even more patent given the lack of a specific pharmacological therapy, with LF only being ameliorated or prevented through the use of agents that alleviate the underlying causes. Hepatic stellate cells (HSCs) are fundamental mediators of LF, which, activated in response to pro-fibrotic stimuli, transdifferentiate from a quiescent phenotype into myofibroblasts that deposit large amounts of fibrotic tissue and mediate pro-inflammatory effects. In recent years, much effort has been devoted to understanding the mechanisms through which HSCs are activated or inactivated. Using cell culture and/or different animal models, numerous studies have shown that autophagy is enhanced during the fibrogenic process and have provided specific evidence to pinpoint the fundamental role of autophagy in HSC activation. This effect involves - though may not be limited to - the autophagic degradation of lipid droplets. Several hepatoprotective agents have been shown to reverse the autophagic alteration present in LF, but clinical confirmation of these effects is pending. On the other hand, there is evidence that implicates autophagy in several anti-fibrotic mechanisms in HSCs that stimulate HSC cell cycle arrest and cell death or prevent the generation of pro-fibrotic mediators, including excess collagen accumulation. The objective of this review is to offer a comprehensive analysis of published evidence of the role of autophagy in HSC activation and to provide hints for possible therapeutic targets for the treatment and/or prevention of LF related to autophagy. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

[Inhibitory effect of Xinhui citrus fermentation liquor on liver fibrosis in mice]

OBJECTIVE

To investigate the inhibitory effect of Xinhui citrus fermentation liquor on liver fibrosis in mice.

OBJECTIVE

Mouse models of liver fibrosis were established by intraperitoneal injection of CCl₄ in 105 male C57BL/6 mice, followed by gavage of 0.1 mL 40% CCl₄ olive oil 3 times a week (model group, n=49) or daily gavage of citrus liquor at the dose of 0.26 mL (citrus liquor group, n=56) for 8 weeks. Seven mice receiving only olive oil treatment (0.1 mL, 3 times a week) and another 7 treated with citrus liquor served as the control group. Liver tissues and serum samples were collected from 7 mice in the citrus liquor group and model group each week and from the mice in the two control groups at the 8th week for pathological examination of the liver tissues using HE staining and Sirius red staining and for determination of the biochemical indexes of liver function.

OBJECTIVE

The mice in the model group showed progressively worsened liver fibrosis with obvious hepatic steatosis, necrosis and inflammatory cell infiltration. These liver pathologies were much ameliorated in citrus liquor group, which showed significantly reduced vacuolation, inflammatory cell infiltration, collagen deposition and the Ishak score of the liver tissue (P < 0.05). Serum levels of cholyglycine, alanine aminotransferase, transglutaminase and alanine aminotransferase were all significantly lower in citrus liquor group than in the model group (P < 0.05).

OBJECTIVE

Xinhui citrus fermentation liquor has protective effect on the liver and can significantly ameliorate liver fibrosis in mice.

Nephroprotective effect of gastrodin against lead-induced oxidative stress and inflammation in mice by the GSH, Trx, Nrf2 antioxidant system, and the HMGB1 pathway

Gastrodin (GAS), the main phenolic glycoside derivative from Gastrodiaelata Blume, has several bio-activities. However, the molecular mechanisms of these protective actions currently remain unclear. This study aimed to investigate the mechanisms of GAS on lead (Pb)-induced oxidative stress and inflammation in the kidneys and primary kidney mesangial cells. Results indicated that GAS improved Pb-induced renal dysfunction and morphological changes in mice. GAS ameliorated Pb-induced inflammation in kidneys by reducing the TNF-α and IL-6 levels. GAS inhibited Pb-induced oxidative stress by regulating the glutathione, thioredoxin (Trx), and Nrf2 antioxidant systems. Furthermore, GAS supplementation increased the activation of SOD, GPx, HO-1, and NQO1 in the kidneys. GAS decreased the expression levels of HMGB1, TLR4, RAGE, MyD88, and NF-κB. These results were further confirmed in primary kidney mesangial cells. Collectively, this study demonstrated that GAS alleviated Pb-induced kidney oxidative stress and inflammation by regulating the antioxidant systems and the Nrf2 signaling pathway. Highlights Gastrodin ameliorated Pb-induced kidney injury in mice.Gastrodin inhibited oxidative stress and inflammation in kidneys.Gastrodin activated the GSH, Trx and Nrf2 antioxidant system in kidneys.Gastrodin inhibited the activities of HMGB1. RAGE, TLR4, and MyD88.

Dihydromyricetin improves mitochondrial outcomes in the liver of alcohol-fed mice via the AMPK/Sirt-1/PGC-1α signaling axis

Alcoholic liver disease (ALD), due to the multifactorial damage associated with alcohol (ethanol) consumption and metabolism, is one of the most prevalent liver diseases in the United States. The liver is the primary site of ethanol metabolism and is subsequently injured due to the production of reactive oxygen species (ROS), acetaldehyde, and metabolic stress. Building evidence suggests that dihydromyricetin (DHM), a bioactive flavonoid isolated from Hovenia dulcis, provides hepatoprotection by enhancing ethanol metabolism in the liver by maintaining hepatocellular bioenergetics, reductions of oxidative stress, and activating lipid oxidation pathways. The present study investigates the utility of DHM on hepatic mitochondrial biogenesis via activation of the AMP-activated protein kinase (AMPK)/Sirtuin (Sirt)-1/PPARG coactivator 1 (PGC)-1α signaling pathway. We utilized a forced drinking ad libitum study that chronically fed 30% ethanol to male C57BL/6J mice over 8 weeks and induced ALD pathology. We found that chronic ethanol feeding resulted in the suppression of AMPK activation and cytoplasmic Sirt-1 and mitochondrial Sirt-3 expression, effects that were reversed with daily DHM administration (5 mg/kg; intraperitoneally [i.p.]). Chronic ethanol feeding also resulted in hepatic hyperacetylation of PGC-1α, which was improved with DHM administration and its mediated increase of Sirt-1 activity. Furthermore, ethanol-fed mice were found to have increased expression of mitochondrial transcription factor A (TFAM), reduced mitochondrial content as assessed by mitochondrial DNA to nuclear DNA ratios, and significantly lower levels of hepatic ATP. In contrast, DHM administration significantly increased TFAM expression, hepatic ATP concentrations, and induced mitochondrial expression of respiratory complex III and V. In total, this work demonstrates a novel mechanism of DHM that improves hepatic bioenergetics, metabolic signaling, and mitochondrial viability, thus adding to the evidence supporting the use of DHM for treatment of ALD and other metabolic disorders.

Design and synthesis of 7-O-1,2,3-triazole hesperetin derivatives to relieve inflammation of acute liver injury in mice

Based on the previous research results of our research group, to further improve the anti-inflammatory activity of hesperetin, we substituted triazole at the 7-OH branch of hesperetin. We also evaluated the anti-inflammatory activity of 39 new hesperetin derivatives. All compounds showed inhibitory effects on nitric oxide (NO) and inflammatory factors in lipopolysaccharide-induced RAW264.7 cells. Compound d5 showed a strong inhibitory effect on NO (half maximal inhibitory concentration = 2.34 ± 0.7 μM) and tumor necrosis factor-α, interleukin (IL)-1β, and (IL-6). Structure-activity relationships indicate that 7-O-triazole is buried in a medium-sized hydrophobic cavity that binds to the receptor. Compound d5 can also reduce the reactive oxygen species production and significantly inhibit the expression of inducible NO synthase and cyclooxygenase-2 through the nuclear factor-κB signaling pathway. In vivo results indicate that d5 can reduce liver inflammation in mice with acute liver injury (ALI) induced by CCI₄. In conclusion, d5 may be a candidate drug for treating inflammation associated with ALI.

Bixin attenuates carbon tetrachloride induced oxidative stress, inflammation and fibrosis in kidney by regulating the Nrf2/TLR4/MyD88 and PPAR-γ/TGF-β1/Smad3 pathway

Bixin, an natural carotenoid extracted from the seeds of the Bixa orellana has been shown to possess numerous important pharmacological activities. The present study was aimed to investigate the mechanisms of Bixin on carbon tetrachloride (CCl4)-induced kidney inflammation, fibrosis and oxidative stress in mice. Our results showed that Bixin improved renal damage by decreasing the serum levels of creatinine, urea, uric acid and alleviating kidney fibrosis. Bixin ameliorated CCl4-induced inflammation in kidneys by reducing the levels of TNF-α and IL-1β. Bixin suppressed oxidative stress by decreasing the MDA level and increasing the activation of SOD, CAT and GPx. Furthermore, Bixin increased the levels of PPAR-γ, NQO1, HO-1 and the nuclear translocation of Nrf2 in the kidneys of mice. Bixin supplementation inhibited the activation of TLR4, MyD88, NF-κB, TGF-β and Smad3. Thus, this study demonstrated that Bixin possesses anti-oxidant, anti-inflammatory and anti-fibrosis properties through regulating the Nrf2/TLR4/MyD88 and PPAR-γ/TGF-β1/Smad3 pathways.

Exosomes derived from mmu_circ_0000623-modified ADSCs prevent liver fibrosis via activating autophagy

Prolonged parenchymal cell death leads to activation of fibrogenic cells, extracellular matrix accumulation, and eventually liver fibrosis. Increasing evidence shows that exosomes (Exos) secreted by adipose-derived mesenchymal stem cells (ADSCs) can be used to deliver circular RNAs (circRNAs) to treat liver fibrosis. To explore the uses of circRNA, circRNA expression profiles of hepatic tissue from normal and CCl4-induced mice were analyzed using high-throughput circRNA microarrays. The result showed that mmu_circ_0000623 expression was downregulated in CCl4-induced mice. Bioinformatics analysis and luciferin reporter experiments showed that mmu_circ_0000623 interacted with and regulated miR-125/ATG4D. In vitro and in vivo experiments showed that Exos from ADSCs, especially from mmu_circ_0000623-modified ADSCs, significantly suppressed CCl4-induced liver fibrosis by promoting autophagy activation. Autophagy inhibitor treatment significantly reversed the treatment effects of Exos. Proteins involved in autophagy and autophagy plaques positive for ATG4D expression were regulated by mmu_circ_0000623/miR-125. Our study found that Exos derived from mmu_circ_0000623-modified ADSCs prevented liver fibrosis via activating autophagy.

Epigenetics in Liver Fibrosis: Could HDACs be a Therapeutic Target?

Chronic liver diseases (CLD) represent a worldwide health problem. While CLDs may have diverse etiologies, a common pathogenic denominator is the presence of liver fibrosis. Cirrhosis, the end-stage of CLD, is characterized by extensive fibrosis and is markedly associated with the development of hepatocellular carcinoma. The most important event in hepatic fibrogenesis is the activation of hepatic stellate cells (HSC) following liver injury. Activated HSCs acquire a myofibroblast-like phenotype becoming proliferative, fibrogenic, and contractile cells. While transient activation of HSCs is part of the physiological mechanisms of tissue repair, protracted activation of a wound healing reaction leads to organ fibrosis. The phenotypic changes of activated HSCs involve epigenetic mechanisms mediated by non-coding RNAs (ncRNA) as well as by changes in DNA methylation and histone modifications. During CLD these epigenetic mechanisms become deregulated, with alterations in the expression and activity of epigenetic modulators. Here we provide an overview of the epigenetic alterations involved in fibrogenic HSCs transdifferentiation with particular focus on histones acetylation changes. We also discuss recent studies supporting the promising therapeutic potential of histone deacetylase inhibitors in liver fibrosis.

Endoplasmic reticulum stress and protein degradation in chronic liver disease

Endoplasmic reticulum (ER) stress is easily observed in chronic liver disease, which often causes accumulation of unfolded or misfolded proteins in the ER, leading to unfolded protein response (UPR). Regulating protein degradation is an integral part of UPR to relieve ER stress. The major protein degradation system includes the ubiquitin-proteasome system (UPS) and autophagy. All three arms of UPR triggered in response to ER stress can regulate UPS and autophagy. Accumulated misfolded proteins could activate these arms, and then generate various transcription factors to regulate the expression of UPS-related and autophagy-related genes. The protein degradation process regulated by UPR has great significance in many chronic liver diseases, including non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), viral hepatitis, liver fibrosis, and hepatocellular carcinoma(HCC). In most instances, the degradation of excessive proteins protects cells with ER stress survival from apoptosis. According to the specific functions of protein degradation in chronic liver disease, choosing to promote or inhibit this process is promising as a potential method for treating chronic liver disease.

Exosomal miR-223 derived from natural killer cells inhibits hepatic stellate cell activation by suppressing autophagy

Background

Activation of hepatic stellate cells (HSCs) is a prominent driver of liver fibrosis. We previously demonstrated that exosomes derived from natural killer (NK) cells (NK-Exo) attenuated TGF-β1-induced HSC activation. Herein, this study was designed to investigate the mechanism underlying the action of NK-Exo.

Methods

NK-Exo was isolated from NK-92MI cells and then administered into TGF-β1-treated LX-2 (human HSC line) cells. MiR-223 expression in NK-Exo was downregulated by transfecting NK-92MI cells with miR-223 inhibitor followed by exosome isolation. The HSC activation was evaluated by determining cell proliferation using CCK-8 assay and measuring the protein levels of α-SMA and CoL1A1 using western blot in LX-2 cells. The expression of miR-223 was detected by qRT-PCR. The interaction between miR-223 and ATG7 was analyzed by a dual-luciferase activity assay. The autophagy was evaluated by measuring the autophagy-related proteins using western blot.

Results

miR-223 was highly expressed in NK-Exo and inhibition of miR-223 expression in NK-Exo abrogated the inhibitory effect of NK-Exo on TGF-β-induced HSC activation. ATG7 was confirmed as a direct target of miR-223. Furthermore, treatment with the autophagy activator rapamycin and ATG7 overexpression in LX-2 cells abolished the HSC activation-suppressive effect of NK-Exo.

Conclusion

NK-Exo attenuated TGF-β-induced HSC activation by transferring miR-223 that inhibited autophagy via targeting ATG7.

Resveratrol Modulates Transforming Growth Factor-Beta (TGF-β) Signaling Pathway for Disease Therapy: A New Insight into Its Pharmacological Activities

Resveratrol (Res) is a well-known natural product that can exhibit important pharmacological activities such as antioxidant, anti-diabetes, anti-tumor, and anti-inflammatory. An evaluation of its therapeutic effects demonstrates that this naturally occurring bioactive compound can target different molecular pathways to exert its pharmacological actions. Transforming growth factor-beta (TGF-β) is an important molecular pathway that is capable of regulating different cellular mechanisms such as proliferation, migration, and angiogenesis. TGF-β has been reported to be involved in the development of disorders such as diabetes, cancer, inflammatory disorders, fibrosis, cardiovascular disorders, etc. In the present review, the relationship between Res and TGF-β has been investigated. It was noticed that Res can inhibit TGF-β to suppress the proliferation and migration of cancer cells. In addition, Res can improve fibrosis by reducing inflammation via promoting TGF-β down-regulation. Res has been reported to be also beneficial in the amelioration of diabetic complications via targeting the TGF-β signaling pathway. These topics are discussed in detail in this review to shed light on the protective effects of Res mediated via the modulation of TGF-β signaling.

Ampelopsin inhibits high glucose-induced extracellular matrix accumulation and oxidative stress in mesangial cells through activating the Nrf2/HO-1 pathway

Oxidative stress plays an important role in diabetic nephropathy (DN), which is a diabetic complication. Ampelopsin (AMP) is a natural flavonoid that has been found to possess antidiabetic and antioxidative activities. However, the effect of AMP on DN remains unclear. In this study, we aimed to evaluate the protective effect of AMP on glomerular mesangial cells (MCs) exposed to high glucose (HG). We found that AMP improved HG-caused cell viability reduction in MCs. AMP significantly suppressed the intracellular ROS production and expression levels of ROS producing enzymes NADPH oxidase 2 (NOX2) and NOX4. Increased of NOX activity in HG-stimulated MCs was suppressed by AMP. Pretreatment with AMP inhibited extracellular matrix (ECM) accumulation in HG-stimulated MCs with decreased expression levels of fibronectin (FN) and collagen type IV (Col IV). Furthermore, AMP elevated the expression levels of nuclear Nrf2 and heme oxygenase-1 (HO-1), as well as increased the mRNA levels of Nrf2-driven genes NAD(P)H dehydrogenase quinone-1 (NQO-1) and HO-1 in HG-treated MCs. Knockdown of Nrf2 reversed the protective effects of AMP against HG-induced oxidative stress and EMC accumulation in MCs. In conclusion, these findings indicated that AMP protected MCs from HG-induced oxidative damage and ECM accumulation, which might be mediated by Nrf2/HO-1 pathway.

Effects of gastrodin against carbon tetrachloride induced kidney inflammation and fibrosis in mice associated with the AMPK/Nrf2/HMGB1 pathway

Gastrodin (GAS), the main phenolic glycoside extracted from Gastrodia elata Blume, exhibits potential renoprotective properties.