Polydatin protects against carbon tetrachloride-induced liver fibrosis in mice

Mitochondrial quality control in liver fibrosis: Epigenetic hallmarks and therapeutic strategies

BACKGROUND AND AIM

Mitochondrial quality control (MQC) plays a significant role in the progression of liver fibrosis, with key processes such as mitochondrial fission, fusion, mitophagy and biogenesis maintaining mitochondrial homeostasis. To understand the molecular mechanisms underlying epigenetic regulation of mitochondrial quality control in liver fibrosis, with the aim of uncovering novel therapeutic targets for treating, mitigating, and potentially reversing liver fibrosis, in light of the most recent advances in this field.

METHODS

We searched PubMed, Web of Science, and Scopus for published manuscripts using terms "mitochondrial quality control" "mitochondrial fission" "mitochondrial fusion" "mitochondrial biogenesis" "mitophagy" "liver fibrosis" "epigenetic regulation" "DNA methylation" "RNA methylation" "histone modification" and "non-coding RNA". Manuscripts were collated, studied and carried forward for discussion where appropriate.

RESULTS

Mitochondrial fission, fusion, biogenesis, and mitophagy regulate the homeostasis of mitochondria, and the imbalance of mitochondrial homeostasis can induce liver fibrosis. Epigenetic regulation, including DNA methylation, RNA methylation, histone modifications, and non-coding RNAs, plays a significant role in regulating the processes of mitochondrial homeostasis.

CONCLUSION

Mitochondrial quality control and epigenetic mechanisms are intricately linked to the pathogenesis of liver fibrosis. Understanding these molecular interactions provides insight into potential therapeutic strategies. Further research is necessary to translate these findings into clinical applications, with a focus on developing epigenetic drugs to ameliorate liver fibrosis by modulating MQC and epigenetic pathways.

Aflatoxin-B1-Exposure-Induced Hepatic Injury Could Be Alleviated by Polydatin through Reducing Oxidative Stress, Inhibiting Inflammation and Improving Mitophagy

Aflatoxin B1 (AFB1) is a toxic food/feed pollutant, exerting extensive deleterious impacts on the liver. Oxidative stress and inflammation are considered to be vital contributors to AFB1 hepatotoxicity. Polydatin (PD), a naturally occurring polyphenol, has been demonstrated to protect and/or treat liver disorders caused by various factors through its antioxidant and anti-inflammatory properties. However, the role of PD in AFB1-induced liver injury is still elusive. Therefore, this study was designed to investigate the protective effect of PD on hepatic injury in mice subjected to AFB1. Male mice were randomly divided into three groups: control, AFB1 and AFB1-PD groups. The results showed that PD protected against AFB1-induced hepatic injury demonstrated by the reduced serum transaminase activity, the restored hepatic histology and ultrastructure, which could be attributed to the enhanced glutathione level, the reduced interleukin 1 beta and tumor necrosis factor alpha concentrations, the increased interleukin 10 expression at transcriptional level and the up-regulated mRNA expression related to mitophagy. In conclusion, PD could alleviate AFB1-induced hepatic injury by reducing oxidative stress, inhibiting inflammation and improving mitophagy.

Nootkatone Supplementation Attenuates Carbon Tetrachloride Exposure-Induced Nephrotoxicity in Mice

Nootkatone (NKT), a major ingredient of Alpinia oxyphylla, exhibited potential nephroprotective effects; however, the precise molecular mechanisms remain poorly understood. This study aimed to study the nephroprotective effects of NKT and the underlying mechanisms in a mouse model. Our results showed that NKT pretreatment at the doses of 5, 10, and 20 mg/kg per day for 7 days significantly attenuates carbon tetrachloride (CCl₄)-induced increases of serum BUN and CRE and kidney pathology injury. NKT pretreatment also markedly inhibited oxidative stress, inflammatory response, and the activation of caspases-9 and -3 in kidneys of mice exposed to CCl₄. Meanwhile, NKT pretreatment downregulated the expression of NOX4, IL-1β, IL-6, and TNF-α proteins and NO levels in the kidney tissues. Moreover, NKT pretreatment upregulated the expression of Nrf2 and HO-1 mRNAs, and downregulated the expression of NF-κB, IL-1β, IL-6, TNF-α, and iNOS mRNAs in the kidneys of mice, compared to those in the CCl₄ alone treatment group. In conclusion, our results reveal that NKT supplementation could protect against CCl₄ exposure-induced oxidative stress and inflammatory response in the kidneys by inhibiting NOX4 and NF-κB pathways and activating the Nrf2/HO-1 pathway. Our current study highlights the therapeutic application of NKT for kidney diseases.

Microbiota Dysbiosis and Gut Barrier Dysfunction Associated with Non-Alcoholic Fatty Liver Disease Are Modulated by a Specific Metabolic Cofactors' Combination

The gut is a selective barrier that not only allows the translocation of nutrients from food, but also microbe-derived metabolites to the systemic circulation that flows through the liver. Microbiota dysbiosis occurs when energy imbalances appear due to an unhealthy diet and a sedentary lifestyle. Dysbiosis has a critical impact on increasing intestinal permeability and epithelial barrier deterioration, contributing to bacterial and antigen translocation to the liver, triggering non-alcoholic fatty liver disease (NAFLD) progression. In this study, the potential therapeutic/beneficial effects of a combination of metabolic cofactors (a multi-ingredient; MI) (betaine, N-acetylcysteine, L-carnitine, and nicotinamide riboside) against NAFLD were evaluated. In addition, we investigated the effects of this metabolic cofactors' combination as a modulator of other players of the gut-liver axis during the disease, including gut barrier dysfunction and microbiota dysbiosis. Diet-induced NAFLD mice were distributed into two groups, treated with the vehicle (NAFLD group) or with a combination of metabolic cofactors (NAFLD-MI group), and small intestines were harvested from all animals for histological, molecular, and omics analysis. The MI treatment ameliorated gut morphological changes, decreased gut barrier permeability, and reduced gene expression of some proinflammatory cytokines. Moreover, epithelial cell proliferation and the number of goblet cells were increased after MI supplementation. In addition, supplementation with the MI combination promoted changes in the intestinal microbiota composition and diversity, as well as modulating short-chain fatty acids (SCFAs) concentrations in feces. Taken together, this specific combination of metabolic cofactors can reverse gut barrier disruption and microbiota dysbiosis contributing to the amelioration of NAFLD progression by modulating key players of the gut-liver axis.

Polydatin Ameliorates High Fructose-Induced Podocyte Oxidative Stress via Suppressing HIF-1α/NOX4 Pathway

Long-term high fructose intake drives oxidative stress, causing glomerular podocyte injury. Polydatin, isolated from Chinese herbal medicine Polygonum cuspidatum, is used as an antioxidant agent that protects kidney function. However, it remains unclear how polydatin prevents oxidative stress-driven podocyte damage. In this study, polydatin attenuated high fructose-induced high expression of HIF-1α, inhibited NOX4-mediated stromal cell-derived factor-1α/C-X-C chemokine receptor type 4 (SDF-1α/CXCR4) axis activation, reduced reactive oxygen species (ROS) production in rat glomeruli and cultured podocytes. As a result, polydatin up-regulated nephrin and podocin, down-regulated transient receptor potential cation channel 6 (TRPC6) in these animal and cell models. Moreover, the data from HIF-1α siRNA transfection showed that high fructose increased NOX4 expression and aggravated SDF-1α/CXCR4 axis activation in an HIF-1α-dependent manner, whereas polydatin down-regulated HIF-1α to inhibit NOX4 and suppressed SDF-1α/CXCR4 axis activation, ameliorating high fructose-induced podocyte oxidative stress and injury. These findings demonstrated that high fructose-driven HIF-1α/NOX4 pathway controlled podocyte oxidative stress damage. Intervention of this disturbance by polydatin could help the development of the therapeutic strategy to combat podocyte damage associated with high fructose diet.

Polydatin attenuates tubulointerstitial fibrosis in diabetic kidney disease by inhibiting YAP expression and nuclear translocation

The activation of Yes-associated protein (YAP) pathway is mutually causal with the increase of extracellular matrix (ECM) stiffness. Polydatin (PD) has been proved to have anti-fibrosis effect in diabetic kidney disease (DKD), but it is still a mystery whether PD participates in YAP-related mechano-transduction. Therefore, this study intends to solve the following two problems: 1) To construct an in vitro system of polyacrylamide hydrogels (PA gels) based on the true stiffness of kidneys in healthy and DKD rats, and observe the effect of PD on pathological matrix stiffness-induced YAP expression in renal fibroblasts; 2) Compared with verteporfin (VP), a pharmacological inhibitor of YAP, to explore whether the therapeutic effect of PD on DKD in vivo model is related to the regulation of YAP. In this study, the in vitro system of PA gels with 3 kPa, 12 kPa and 30 kPa stiffness was constructed and determined for the first time to simulate the kidney stiffness of healthy rats, rats with DKD for 8 weeks and 16 weeks, respectively. Compared with the PA gels with 3 kPa stiffness, the PA gels with 12 kPa and 30 kPa stiffness significantly increased the expression of YAP, α-smooth muscle actin (α-SMA) and collagen I, and the production of reactive oxygen species (ROS) in renal fibroblasts, and the PA gels with 30 kPa stiffness were the highest. PD significantly inhibited the above-mentioned changes of fibroblasts induced by pathological matrix stiffness, suggesting that the inhibition of PD on fibroblast-to-myofibroblast transformation and ECM production was at least partially associated with regulating YAP-related mechano-transduction pathway. Importantly, the inhibitory effect of PD on YAP expression and nuclear translocation in kidneys of DKD rats is similar to that of VP, but PD is superior to VP in reducing urinary protein, blood glucose, blood urea nitrogen and serum creatinine, as well as decreasing the expression of α-SMA and collagen I, ROS overproduction and renal fibrosis. Our results prove for the first time from the biomechanical point of view that PD is a potential therapeutic strategy for delaying the progression of renal fibrosis by inhibiting YAP expression and nuclear translocation.

Polydatin: Pharmacological Mechanisms, Therapeutic Targets, Biological Activities, and Health Benefits

Polydatin is a natural potent stilbenoid polyphenol and a resveratrol derivative with improved bioavailability. Polydatin possesses potential biological activities predominantly through the modulation of pivotal signaling pathways involved in inflammation, oxidative stress, and apoptosis. Various imperative biological activities have been suggested for polydatin towards promising therapeutic effects, including anticancer, cardioprotective, anti-diabetic, gastroprotective, hepatoprotective, neuroprotective, anti-microbial, as well as health-promoting roles on the renal system, the respiratory system, rheumatoid diseases, the skeletal system, and women's health. In the present study, the therapeutic targets, biological activities, pharmacological mechanisms, and health benefits of polydatin are reviewed to provide new insights to researchers. The need to develop further clinical trials and novel delivery systems of polydatin is also considered to reveal new insights to researchers.

Limonin relieves TGF-β-induced hepatocyte EMT and hepatic stellate cell activation in vitro and CCl4-induced liver fibrosis in mice via upregulating Smad7 and subsequent suppression of TGF-β/Smad cascade

Liver fibrosis is a pathological process as a result of intrahepatic deposition of excessive extracellular matrix. Epithelial-mesenchymal transition (EMT) of hepatocytes and activation of hepatic stellate cells (HSCs) both play important roles in the etiology of liver fibrosis. Here, we found that limonin repressed transforming growth factor-β1 (TGF-β)-induced EMT in AML-12 hepatocytes and activation of LX-2 HSCs. In both kinds of cells, limonin suppressed TGF-β-provoked Smad2/3 C-terminal phosphorylation and subsequent nuclear translocation. Transcription of Smad2/3-downstream genes was in turn reduced. However, limonin exerted few effects on Smad2/3 phosphorylation at linker region. Mechanistically, limonin increased Smad7 at mRNA level in both AML-12 and LX-2 cells. Knockdown of Smad7 abrogated inhibitory effects of limonin on TGF-β-induced EMT in AML-12 cells and activation of LX-2 cells. Further studies revealed that limonin alleviated mouse liver fibrosis induced by CCl₄. In livers of model mice, limonin upregulated Smad7 and declined C-terminal phosphorylation and nuclear translocation of Smad2/3. Transcription of Smad2/3-responsive genes was also attenuated. Our findings indicated that limonin inhibits TGF-β-induced EMT of hepatocytes and activation of HSCs in vitro and CCl₄-induced liver fibrosis in mice. Upregulated Smad7 which suppresses Smad2/3-dependent gene transcription is implicated in the hepatoprotective activity of limonin.

Resveratrol ameliorates liver fibrosis induced by nonpathogenic Staphylococcus in BALB/c mice through inhibiting its growth

Background

The altered gut microbiota is implicated in the pathogenesis of liver fibrosis. Resveratrol is a candidate for the treatment of liver fibrosis, which could ameliorate the dysregulation of gut microbiota in mice. This study aimed to clarify the role and mechanism of resveratrol in gut microbiota during liver fibrosis.

Methods

A mouse model of liver fibrosis induced by CCl₄ was conducted to assess the effect of resveratrol on liver fibrosis. The changes of gut microbiota in liver fibrotic mice after resveratrol intervention were assessed using 16S ribosomal RNA sequencing. The mechanism of the gut microbiota dysregulation in liver fibrosis was investigated by Sirius red staining, immunohistochemical assay, bacterial translocation (BT), EUB338 fluorescence in situ hybridization, immunofluorescence, trans-epithelial electrical resistance analysis and paracellular permeability analysis.

Results

Resveratrol relieved CCl₄-induced liver fibrosis. Besides, resveratrol restrained the gut microbiota Staphylococcus_lentus and Staphylococcus_xylosus in the liver fibrotic mice, and the Staphylococcus_xylosus and Staphylococcus_lentus facilitated the occurrence of BT and the cultures of them enhanced the permeability of intestine. The in vivo assay corroborated that the excessive Staphylococcus_xylosus and Staphylococcus_lentus canceled the protecting effect of resveratrol on liver fibrosis, and Staphylococcus_xylosus or Staphylococcus_lentus alone had a limited impact on the liver injury of normal mice.

Conclusion

Resveratrol ameliorated liver fibrosis by restraining the growth of Staphylococcus_xylosus and Staphylococcus_lentus.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00463-y.

Polydatin: A Critical Promising Natural Agent for Liver Protection via Antioxidative Stress

Polydatin, one of the natural active small molecules, was commonly applied in protecting and treating liver disorders in preclinical studies. Oxidative stress plays vital roles in liver injury caused by various factors, such as alcohol, viral infections, dietary components, drugs, and other chemical reagents. It is reported that oxidative stress might be one of the main reasons in the progressive development of alcohol liver diseases (ALDs), nonalcoholic liver diseases (NAFLDs), liver injury, fibrosis, hepatic failure (HF), and hepatocellular carcinoma (HCC). In this paper, we comprehensively summarized the pharmacological effects and potential molecular mechanisms of polydatin for protecting and treating liver disorders via regulation of oxidative stress. According to the previous studies, polydatin is a versatile natural compound and exerts significantly protective and curative effects on oxidative stress-associated liver diseases via various molecular mechanisms, including amelioration of liver function and insulin resistance, inhibition of proinflammatory cytokines, lipid accumulation, endoplasmic reticulum stress and autophagy, regulation of PI3K/Akt/mTOR, and activation of hepatic stellate cells (HSCs), as well as increase of antioxidant enzymes (such as catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH), superoxide dismutase (SOD), glutathione reductase (GR), and heme oxygenase-1 (HO-1)). In addition, polydatin acts as a free radical scavenger against reactive oxygen species (ROS) by its phenolic and ethylenic bond structure. However, further clinical investigations are still needed to explore the comprehensive molecular mechanisms and confirm the clinical treatment effect of polydatin in liver diseases related to regulation of oxidative stress.

Old dog, new tricks: Polydatin as a multitarget agent for current diseases

Polydatin (PD) is a natural single-crystal product that is primarily extracted from the traditional plant Polygonum cuspidatum Sieb. et Zucc. Early research showed that PD exhibited a variety of biological activities. PD has attracted increasing research interest since 2014, but no review comprehensively summarized the new findings. A great gap between its biological activities and drug development remains. It is necessary to summarize new findings on the pharmacological effects of PD on current diseases. We propose that PD will most likely be used in cardiac and cerebral ischaemia/reperfusion-related diseases and atherosclerosis in the future. The present work classified these new findings according to diseases and summarized the main effects of PD via specific mechanisms of action. In summary, we found that PD played a therapeutic role in a variety of diseases, primarily via five mechanisms: antioxidative effects, antiinflammatory effects, regulation of autophagy and apoptosis, maintenance of mitochondrial function, and lipid regulation.

Supplementation with a Specific Combination of Metabolic Cofactors Ameliorates Non-Alcoholic Fatty Liver Disease, Hepatic Fibrosis, and Insulin Resistance in Mice

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) have emerged as the leading causes of chronic liver disease in the world. Obesity, insulin resistance, and dyslipidemia are multifactorial risk factors strongly associated with NAFLD/NASH. Here, a specific combination of metabolic cofactors (a multi-ingredient; MI) containing precursors of glutathione (GSH) and nicotinamide adenine dinucleotide (NAD+) (betaine, N-acetyl-cysteine, L-carnitine and nicotinamide riboside) was evaluated as effective treatment for the NAFLD/NASH pathophysiology. Six-week-old male mice were randomly divided into control diet animals and animals exposed to a high fat and high fructose/sucrose diet to induce NAFLD. After 16 weeks, diet-induced NAFLD mice were distributed into two groups, treated with the vehicle (HFHFr group) or with a combination of metabolic cofactors (MI group) for 4 additional weeks, and blood and liver were obtained from all animals for biochemical, histological, and molecular analysis. The MI treatment reduced liver steatosis, decreasing liver weight and hepatic lipid content, and liver injury, as evidenced by a pronounced decrease in serum levels of liver transaminases. Moreover, animals supplemented with the MI cocktail showed a reduction in the gene expression of some proinflammatory cytokines when compared with their HFHFr counterparts. In addition, MI supplementation was effective in decreasing hepatic fibrosis and improving insulin sensitivity, as observed by histological analysis, as well as a reduction in fibrotic gene expression (Col1α1) and improved Akt activation, respectively. Taken together, supplementation with this specific combination of metabolic cofactors ameliorates several features of NAFLD, highlighting this treatment as a potential efficient therapy against this disease in humans.

Structural characterization and amelioration of sulfated polysaccharides from Ganoderma applanatum residue against CCl4-induced hepatotoxicity

Natural polysaccharides and their derivatives have attracted academic attention due to their extensive physiological activities. However, the hepatoprotective effects against carbon tetrachloride (CCl₄) toxicity have not been well elucidated. The objectives of this study were to characterize the structural properties of sulfated Ganoderma applanatum residue polysaccharides (SGRP) and to evaluate their inhibitory effects on liver fibrosis caused by oxidative stress and inflammation. Our in vivo study showed that SGRP was hepatoprotective in CCl₄-induced chronic liver injury mice. It reduced the histopathological damages, down-regulated CYP2E1 (cytochrome P450 2E1) expression, reduced serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, improved the anti-oxidative and anti-inflammatory properties, inhibited TLR4/NF-κB signaling pathway, and reduced the release of inflammatory cytokines. The structural studies indicated that SGRP is a heteropolysaccharide with 7.8% sulfur content and α-linked residue. Our study projects SGRP as a potential candidate in anti-fibrosis treatment by using it as a food supplement or in medicines produced by pharmaceutical industries.

The Space of Disse: The Liver Hub in Health and Disease

Since it was first described by the German anatomist and histologist, Joseph Hugo Vincenz Disse, the structure and functions of the space of Disse, a thin perisinusoidal area between the endothelial cells and hepatocytes filled with blood plasma, have acquired great importance in liver disease. The space of Disse is home for the hepatic stellate cells (HSCs), the major fibrogenic players in the liver. Quiescent HSCs (qHSCs) store vitamin A, and upon activation they lose their retinol reservoir and become activated. Activated HSCs (aHSCs) are responsible for secretion of extracellular matrix (ECM) into the space of Disse. This early event in hepatic injury is accompanied by loss of the pores—known as fenestrations—of the endothelial cells, triggering loss of balance between the blood flow and the hepatocyte, and underlies the link between fibrosis and organ dysfunction. If the imbalance persists, the expansion of the fibrotic scar followed by the vascularized septae leads to cirrhosis and/or end-stage hepatocellular carcinoma (HCC). Thus, researchers have been focused on finding therapeutic targets that reduce fibrosis. The space of Disse provides the perfect microenvironment for the stem cells niche in the liver and the interchange of nutrients between cells. In the present review article, we focused on the space of Disse, its components and its leading role in liver disease development.

Hepatic stellate cells specific liposomes with the Toll-like receptor 4 shRNA attenuates liver fibrosis

The hepatic stellate cells (HSCs) play a significant role in the onset of liver fibrosis, which can be treated by the inhibition and reversal of HSC activation. The RNA interference-mediated TLR4 gene silencing might be a potential therapeutic approach for liver fibrosis. The crucial challenge in this method is the absence of an efficient delivery system for the RNAi introduction in the target cells. HSCs have an enhanced capacity of vitamin A intake as they contain retinoic acid receptors (RARs). In the current study, we developed cationic liposomes modified with vitamin A to improve the specificity of delivery vehicles for HSCs. The outcome of this study revealed that the VitA-coupled cationic liposomes delivered the TLR4 shRNA to aHSCs more efficiently, as compared to the uncoupled cationic liposomes, both in the in vitro and in vivo conditions. Besides, as evident from the outcome of this study, the TLR4 gene silencing inhibited the HSCs activation and attenuated the liver fibrosis via the NF-κB transcriptional inactivation, pro-inflammatory cytokines secretion and reactive oxygen species (ROS) synthesis. Thus, the VitA-coupled liposomes encapsulated with the TLR4-shRNA might prove as an efficient therapeutic agent for liver fibrosis.

Resveratrol contributes to the inhibition of liver fibrosis by inducing autophagy via the microRNA‑20a‑mediated activation of the PTEN/PI3K/AKT signaling pathway

Liver fibrosis (LF) is a healing response to wounds resulting in liver injury that can cause liver failure or even cancer without functional prevention. Resveratrol (RSV) has been suggested to exert biological effects against various human diseases. MicroRNA-20a (miRNA/miR-20a) has been shown to promote disease progression. The present study aimed to assess the mechanisms through which RSV induces autophagy and activates the miR-20a-mediated phosphatase and tensin homolog (PTEN)/PI3K/AKT signaling pathway in LF. First, a rat model of carbon tetrachlo-ride (CCL₄)-induced LF and a cell model of platelet-derived growth factor (PDGF)-BB-stimulated HSC-T6 cells were established for use in subsequent experiments. Subsequently, RSV at a range of concentrations was injected into the model rats with LF. Indicators related to liver injury, oxidative stress and fibrosis were determined in the rats with LF. The RSV-treated HSC-T6 cells were subjected to transfection with miR-20a mimic and PTEN overexpression plasmid to assess the levels of liver injury and LF. A dual-luciferase reporter gene assay was performed to verify the binding sites between PTEN and miR-20a. RSV was found to alleviate LF in rats, and autophagy was enhanced in the rats with LF following RSV treatment. Furthermore, the activation of the PTEN/PI3K/AKT axis attenuated LF, which was reversed by transfection with miR-20a mimic. RSV reversed the inhibitory effects of miR-20a on PTEN expression, reducing miR-20a expression and promoting PTEN, PI3K and p-AKT protein expression, thus attenuating LF. On the whole, the present study demonstrates that RSV induces autophagy and activates the miR-20a-mediated PTEN/PI3K/AKT signaling pathway to attenuate LF. These findings may lead to the development of potential therapeutic strategies for LF.

A comprehensive review of natural products to fight liver fibrosis: Alkaloids, terpenoids, glycosides, coumarins and other compounds

The discovery of drugs to treat liver fibrosis has long been a challenge over the past decades due to its complicated pathogenesis. As a primary approach for drug development, natural products account for 30% of clinical drugs used for disease treatment. Therefore, natural products are increasingly important for their medicinal value in liver fibrosis therapy. In this part of the review, special focus is placed on the effect and mechanism of natural compounds, including alkaloids, terpenoids, glycosides, coumarins and others. A total of 36 kinds of natural compounds demonstrate significant antifibrotic effects in various liver fibrosis models in vivo and in hepatic stellate cells (HSCs) in vitro. Revealing the mechanism will provide further basis for clinical conversion, as well as accelerate drug discovery. The mechanism was further summarized with the finding of network regulation by several natural products, such as oxymatrine, paeoniflorin, ginsenoside Rg1 and taurine. Moreover, there are still improvements needed in investigating clinical efficacy, determining mechanisms, and combining applications, as well as semisynthesis and modification. Therefore, natural products area promising resource for agents that protect against liver fibrosis.

NADPH Oxidase Inhibition in Fibrotic Pathologies

Significance: Fibrosis is a stereotypic, multicellular tissue response to diverse types of injuries that fundamentally result from a failure of cell/tissue regeneration. This complex tissue remodeling response disrupts cellular/matrix composition and homeostatic cell-cell interactions, leading to loss of normal tissue architecture and progressive loss of organ structure/function. Fibrosis is a common feature of chronic diseases that may affect the lung, kidney, liver, and heart. Recent Advances: There is emerging evidence to support a combination of genetic, environmental, and age-related risk factors contributing to susceptibility and/or progression of fibrosis in different organ systems. A core pathway in fibrogenesis involving these organs is the induction and activation of nicotinamide adenine dinucleotide phosphate oxidase (NOX) family enzymes. Critical Issues: We explore current pharmaceutical approaches to targeting NOX enzymes, including repurposing of currently U.S. Food and Drug Administration (FDA)-approved drugs. Specific inhibitors of various NOX homologs will aid establishing roles of NOXs in the various organ fibroses and potential efficacy to impede/halt disease progression. Future Directions: The discovery of novel and highly specific NOX inhibitors will provide opportunities to develop NOX inhibitors for treatment of fibrotic pathologies.

Polydatin attenuates hepatic stellate cell proliferation and liver fibrosis by suppressing sphingosine kinase 1

Sphingosine kinase 1 (SphK1) plays critical roles in the activation of hepatic stellate cells (HSCs) and liver fibrosis. Our previous study found that polydatin ameliorates chronic liver injury and fibrosis by inhibiting oxidative stress. However, whether polydatin exerts an anti-fibrotic effect on liver fibrosis dependent on SphK1 signaling is unknown. We aimed to investigate the role of polydatin in SphK1, which mediates HSC activation and liver fibrosis. C57BL/6 mice were induced using CCl₄ 5 μL g^-1 i.p. twice a week for 6 weeks and treated with or without polydatin. Human immortalized HSC line (LX-2) was induced using platelet-derived growth factor-BB (PDGF-BB) or adenovirus-SphK1 and treated with polydatin. Hepatic macrophage filtration, collagen deposition, expression of α-smooth muscle, active caspase-3, and terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells were markedly increased in mice induced by CCl₄ for 6 weeks. In contrast, polydatin attenuated collagen synthesis and hepatocyte apoptosis. Furthermore, polydatin exhibited significant anti-proliferative activity against PDGF-BB-induced activated hepatic stellate cells (HSCs). SphK1 was strongly induced in mice exposed to CCl₄, whereas its expression and activity were inhibited by polydatin treatment. Finally, SphK1 overexpression in LX-2 cells promoted proliferation of activated HSCs, which could not be reversed by polydatin treatment. These results demonstrate that polydatin attenuates HSC proliferation and activation through inhibition of SphK1 signaling, contributing to the suppression of liver fibrosis.

Oridonin ameliorates carbon tetrachloride-induced liver fibrosis in mice through inhibition of the NLRP3 inflammasome

Liver fibrosis is characterized by the activation of hepatic stellate cells (HSCs) and accumulation of the extracellular matrix. There are limitations in the current therapies for liver fibrosis. Recently, oridonin was shown to induce apoptosis in HSCs. Thus, we aimed to determine the roles of oridonin in chronic liver injury and fibrosis. Liver fibrosis was induced by CCl4 in mice injected intraperitoneally with oridonin for 6 weeks. The administration of oridonin significantly attenuated liver injury and reduced ALT levels. In addition, Sirius Red staining and the expression of α-smooth muscle actin (α-SMA) were significantly reduced by oridonin in murine livers with fibrosis. The expression of NLRP3, caspase-1, and IL-1β was downregulated with the oridonin treatment. Furthermore, the expression of F4/80 in liver tissues was also decreased by oridonin treatment. These results demonstrate that oridonin ameliorates chronic liver injury and fibrosis. Mechanically, oridonin may inhibit the activity of the NLRP3 inflammasome and inflammation in the liver. These results highlight the potential of oridonin as a therapeutic agent for liver fibrosis.

Polydatin relieves paraquat-induced human MRC-5 fibroblast injury through inhibiting the activation of the NLRP3 inflammasome

Background

Paraquat (PQ) is a herbicide that is highly toxic to the lungs and kidneys. When it enters the body, it will disrupt the balance of the microenvironment in the body, induce a large number of inflammatory factors and cause cell damage. Polydatin (PD), resveratrol glycoside, has multiple pharmacological effects. However, the protective effect of PD on human embryo lung fibroblast damage caused by PQ poisoning has not been reported. The purpose of this study was to investigate the regulatory effect of PD on human embryo lung fibroblast damage caused by PQ poisoning.

Method

The optimal experimental concentration of PQ for human embryonic lung fibroblast MRC-5 was 100 µmol/L, and then the cells of 100 µmol/L PQ group were treated with different concentrations of PD for 24 h. MTT assay to detect MRC-5 cell viability and flow cytometry to detect apoptosis. The corresponding kit was used to detect the contents of glutathione peroxidase (GSH-PX), malondialdehyde (MDA) and superoxide dismutase (SOD). Enzyme-linked immunosorbent assay (ELISA) to detect the levels of related inflammatory factors tumor necrosis factor alpha (TNF-α), transforming growth factor beta (TGF-β), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6). Western blot detection of NLRP3 inflammatory body activation-related protein expression.

Results

Compared with the PQ group, cell activity, GSH-Px content, and SOD content in PD intervention group were significantly increased, while apoptosis, MDA content, inflammatory factor level, and activation-related proteins of the NLRP3 inflammasome were significantly reduced and were dose-dependent.

Conclusions

PD can relieve PQ-induced human MRC-5 fibroblasts injury by reducing the inflammatory response, improving the antioxidant stress capacity, and inhibiting the activation of the NLRP3 inflammasome.

Nanodrug with ROS and pH Dual-Sensitivity Ameliorates Liver Fibrosis via Multicellular Regulation

Liver fibrosis currently represents a global health problem without effective pharmacotherapeutic strategies. The clinical translation of polydatin, a promising natural anti-fibrotic drug candidate with broad anti-inflammatory and antioxidant capabilities, remains a major challenge due to its limited water solubility and tissue absorption. Herein, a polydatin-loaded micelle (PD-MC) based on reactive oxygen species (ROS) and pH dual-sensitive block polymer PEG-P(PBEM-co-DPA) is developed. The micelle exerts great potential in improving the biocompatibility of polydatin and shows highly efficient liver-targeted drug release in response to the fibrotic microenvironment. Both in vitro and in vivo studies demonstrate that PD-MC can significantly suppress inflammatory response and oxidative stress, reduce hepatocyte apoptosis, and avert activation of macrophages and hepatic stellate cells. More excitingly, the blank micelle itself promotes the hepatic ROS consumption at the pathologic site to provide anti-inflammatory benefits. These favorable therapeutic virtues of targeting multiple cell types endow PD-MC with remarkable efficacy with minimal side effects in liver fibrosis treatment. Thus, PD-MC holds great potential to push forward the clinical application of polydatin in pharmacotherapeutic approaches against liver fibrosis.

Improvement of Mitochondrial Activity and Fibrosis by Resveratrol Treatment in Mice with Schistosoma japonicum Infection

Schistosomiasis caused by Schistosoma japonicum is a major parasitic disease in the People's Republic of China. Liver fibrosis is the main pathological mechanism of schistosomiasis, and it is also the major lesion. The common drug used for its treatment, praziquantel (PZQ), does not have a marked effect on liver fibrosis. Resveratrol (RSV), which is an antioxidant, improves mitochondrial function and also attenuates liver fibrosis. The combination of PZQ and RSV has been found to have a synergistic antischistosomal effect on Schistosoma mansoni; additionally, the activity of PZQ is enhanced in the presence of RSV. Here, we examine the therapeutic effects of RSV on the S. japonicum infection in a mouse model, and we investigate RSV as a novel therapeutic agent for mitochondrial function and schistosomiasis-associated liver fibrosis (SSLF). Mitochondrial membrane potential was examined using flow cytometry analysis. The expression of the mitochondrial biogenesis genes PGC-α and fibrosis-associated genes collagen I, collagen III and α-SMA were examined using western blot analysis. Fibrosis-associated histological changes were examined using Masson trichrome staining. Additionally, the effects of RSV on S. japonicum adult worms were examined using scanning electron microscopy and transmission electron microscopy. RSV treatment improved mitochondrial function by increasing membrane potential and increasing PGC-α expression (mitochondrial biogenesis). Further, RSV attenuated liver injury, including liver scarring, by decreasing collagen deposition and the extent of fibrosis, based on the decrease in expression of the fibrosis-related genes. RSV also decreased the adult worm count and caused considerable physical damage to the worm. These results indicate that RSV upregulates mitochondrial biogenesis and inhibits fibrosis. RSV may have potential as a therapeutic target for the treatment of fibrosis in schistosomiasis.

Protective Effects of Propolis and Probiotic Lactobacillus acidophilus against Carbon Tetrachloride-Induced Hepatotoxicity in Rats

Background: Propolis (PRS) and probiotic bacteria Lactobacillus are natural products used as dietary supplement for their therapeutic benefits. This study was performed to examine the possible hepatoprotective effect of PRS and probiotics (PRCs) against carbon tetrachloride-induced liver injury. Methods: Experimentally, intoxicated rats received 0.5 ml/kg CCl4 (i.p.) daily for six days, pretreated rats received per os PRS 100 mg/kg or PRCs 109 CFU for six days followed by a single dose of 0.5 ml/kg CCl4. Control groups received either PRS, PRCs or olive oil for six days. Then, serum biochemistry (total protein, cholesterol, triglycerides and albumin) and oxidative stress parameters were measured. Results: We showed that CCl4 treatment was associated with an increase of the serum aspartate amino transferase (AST), alanine aminotransferase (ALT), cholesterol and triglycerides levels. In parallel, serum total protein, albumin and blood sugar levels were significantly decreased. Regarding the oxidative stress parameters, catalase and glutathione S-transferase (GST) levels were lower, conversely to the lipid peroxidation (MDA). Conclusion: Our results strongly support that administration of PRS and PRCs may significantly protect liver against CCl4-induced toxicity by enhancing antioxidative stress pathway and preventing lipid peroxidation.

Network Pharmacology-Based Prediction of the Active Compounds, Potential Targets, and Signaling Pathways Involved in Danshiliuhao Granule for Treatment of Liver Fibrosis

This study aims to predict the active ingredients, potential targets, signaling pathways and investigate the “ingredient-target-pathway” mechanisms involved in the pharmacological action of Danshiliuhao Granule (DSLHG) on liver fibrosis. Pharmacodynamics studies on rats with liver fibrosis showed that DSLHG generated an obvious anti-liver fibrosis action. On this basis, we explored the possible mechanisms underlying its antifibrosis effect using network pharmacology approach. Information about compounds of herbs in DSLHG was collected from TCMSP public database and literature. Furthermore, the oral bioavailability (OB) and drug-likeness (DL) were screened according to ADME features. Compounds with OB≥30% and DL≥0.18 were selected as active ingredients. Then, the potential targets of the active compounds were predicted by pharmacophore mapping approach and mapped with the target genes of the specific disease. The compound-target network and Protein-Protein Interaction (PPI) network were built by Cytoscape software. The core targets were selected by degree values. Furthermore, GO biological process analysis and KEGG pathway enrichment analysis were carried out to investigate the possible mechanisms involved in the anti-hepatic fibrosis effect of DSLHG. The predicted results showed that there were 108 main active components in the DSLHG formula. Moreover, there were 192 potential targets regulated by DSLHG, of which 86 were related to liver fibrosis, including AKT1, EGFR, and IGF1R. Mechanistically, the anti-liver fibrosis effect of DSLHG was exerted by interfering with 47 signaling pathways, such as PI3K-Akt, FoxO signaling pathway, and Ras signaling pathway. Network analysis showed that DSLHG could generate the antifibrosis action by affecting multiple targets and multiple pathways, which reflects the multicomponent, multitarget, and multichannel characteristics of traditional Chinese medicine and provides novel basis to clarify the mechanisms of anti-liver fibrosis of DSLHG.

Efficiency of Sophora flavescens-Fructus Ligustri Lucidi Drug Pairs in the Treatment of Liver Fibrosis Based on the Response Surface Method

The pairing of Sophora flavescens and Fructus Ligustri lucidi is taken from Shi Jinmo Medicine. The idea behind this pairing was inspired by the similarity in pharmacological effects of the two herbal drugs, both of which are known to be effective in the treatment and protection against liver fibrosis. To quantitatively study the extent of the interaction between these drugs and the effect of pairing on the treatment of liver fibrosis, an animal model of liver fibrosis mice was established by intraperitoneal injection of low-dose carbon tetrachloride. The drugs were then administered individually, or in predefined compatibility ratio pairs, by gavage, and the effects on indexes of liver fibrosis were observed. The multisynthetic index method was adopted using Matlab software in order to construct a three-dimensional response surface map of the integration effect and conduct interaction analysis of Sophora flavescens and Fructus Ligustri lucidi. The quadratic surface fitting pattern was designed by quadratic regression to determine the optimal range of each drug. The obtained results show that when the compatibility ratio of Sophora flavescens-Fructus Ligustri lucidi drug pairs is less than or equal to 1:1, their therapeutic effect is enhanced by synergy (interaction value ranging between -0.2 and -1). Overall, the synergy of the high-dose drug pairs is stronger than that of the low-dose drug pairs. The optimal dose ranges are 6~12 g and 8~17 g for Sophora flavescens and Fructus Ligustri lucidi, respectively.

The hepatoprotective effect of polysaccharides from Pleurotus ostreatus on carbon tetrachloride-induced acute liver injury rats

This study was conducted to evaluate the hepatoprotective effect of polysaccharides from Pleurotus ostreatus (POP) on carbon tetrachloride-induced acute liver injury (ALI) in rats. The hepatoprotective effect of POP against ALI was reflected by the decreased alanine transaminase and aspartate transaminase levels in blood, increased superoxide dismutase, catalase, and glutathione peroxidase levels, and decreased malondialdehyde levels in blood and liver. TUNEL and immunohistochemistry analyses showed that TUNEL apoptosis cell rate and Bax, cytochrome C, caspase-3, caspase-9, and apoptosis-inducing factor expression levels were obviously decreased, whereas Bcl-2 expression levels obviously increased after POP treatment. A total of 11 metabolites belonging to energy, amino acid, fatty acid, and gut bacteria metabolism were identified as biomarkers by using metabolite analysis of liver homogenate based on ultra-performance liquid chromatography-tandem mass spectrometry. POP exhibited hepatoprotective effects on CCl₄-induced ALI, and the underlying mechanism is correlated with antioxidants that regulate metabolic pathway disorders and alleviate liver mitochondria apoptosis.

Polydatin ameliorates dextran sulfate sodium-induced colitis by decreasing oxidative stress and apoptosis partially via Sonic hedgehog signaling pathway

BACKGROUND

Inflammation, oxidative stress and epithelial barrier dysfunction have been implicated in inflammatory bowel disease (IBD) pathology. The targeted inhibition of these features may represent a promising therapeutic strategy for IBD. Polydatin is an effective natural antioxidant that possesses strong antioxidant and anti-apoptotic properties. Thus, we studied the protective effects of polydatin treatments on a mouse model of experimental colitis.

METHODS

Acute colitis was experimentally induced by adding 3% dextran sulfate sodium (DSS) to the drinking water provided to mice for 7 days and by administering different doses of polydatin (15, 30, or 45 mg/kg) during the same period. Mice were also treated with the Sonic hedgehog (Shh) pathway inhibitor cyclopamine to estimate the efficacy of polydatin and Shh inhibitors on colitis. The disease activity index (DAI), colon length, histology, levels of oxidative and apoptotic mediators and levels of Shh pathway components were evaluated.

RESULTS

The polydatin treatment significantly attenuated the DAI, colon shortening and histological damage. In addition, polydatin administration effectively decreased malondialdehyde (MDA) levels and increased the activities of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Polydatin also inhibited apoptosis in mice with colitis by downregulating the expression of the pro-apoptotic proteins Bax, caspase 3 and cleaved caspase 3 and increasing the expression of the anti-apoptotic protein Bcl-2. Furthermore, polydatin modulated Shh signaling pathway activation. After polydatin treatment, the main components of the Shh pathway, including Shh, Patched (Ptc), Smoothened (Smo), and glioblastoma-1 (Gli1), were upregulated at the mRNA and protein levels. Blockade of the Shh pathway using cyclopamine abolished the effects of polydatin on mice with colitis.

CONCLUSION

Based on these observations, polydatin may suppress experimental colitis at least partially by regulating the Shh signaling pathway.

Polydatin attenuates reactive oxygen species-induced airway remodeling by promoting Nrf2-mediated antioxidant signaling in asthma mouse model

Reactive oxygen species (ROS) and epithelial-mesenchymal transition (EMT) play a critical role in transforming growth factor (TGF)-β1-mediated fibrotic airway remodeling in asthma. Polydatin (PD) is a small natural molecule in Chinese medicine; it is isolated from Polygonum cuspidatum and has antioxidative properties. In this study, we aimed to determine whether PD was protective against ROS-induced pulmonary fibrosis in asthma. Ovalbumin (OVA) was used to induce asthma in a mouse model that was treated with or without PD. We also created nuclear factor erythroid 2-related factor 2 (Nrf2) knockdown BEAS-2B cells and investigated whether PD reversed TGF-β1-induced pulmonary epithelial cell EMT by promotion of Nrf2-mediated antioxidation. Immunofluorescence showed that ROS and TGF-β1 expression was significantly increased in lung tissue from the OVA-induced asthma model. PD treatment inhibited activity of ROS and TGF-β1. Immunohistochemistry showed that PD treatment decreased OVA-induced lung ROS, TGF-β1 expression and fibroblasts. Western blotting showed that PD treatment reversed OVA-induced NADPH oxidase (NOX)1/4 expression by promoting Nrf2-mediated heme oxygenase-1 and NADPH dehydrogenase (quinone)-1 expression. PD treatment suppressed OVA-induced EMT and lung fibroblast protein expression in lung tissue. Nrf2 downregulation suppressed the protective effect of PD by promoting TGF-β1-induced ROS and EMT and accumulation of extracellular-matrix-related protein. All these data indicate that PD has potential therapeutic effects in asthma by promoting Nrf2-mediated antioxidation.

Polydatin attenuates diet-induced nonalcoholic steatohepatitis and fibrosis in mice

Scope: Non-alcoholic steatohepatitis (NASH) is characterized by lipid accumulation in hepatocytes and inflammatory cell infiltration. In view of the anti-oxidative and anti-inflammatory effects of polydatin, the current study aimed to investigate the pharmacological effects of polydatin on NASH and its related fibrosis. Methods: C57BL/6 mice were fed with methionine-choline deficient (MCD) diet to induce NASH and liver fibrosis, and treated with or without polydatin (5 mg/kg, every other day, i.p) for 4 weeks. HepG2 cells induced by palmitic acid (PA) were treated with polydatin. Results: The elevations of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), active caspase-3, TUNEL-positive cells, and triglyceride content were decreased by polydatin treatment. In addition, administration of polydatin to MCD-fed mice reduced oxidative stress by down-regulating NOX4 enzymes. Furthermore, the reduction in inflammation and CD68 macrophage activation correlated with inhibition of toll-like receptor (TLR)-4/NF-κB p65 signaling pathway by polydatin treatment. Polydatin also attenuated lipid accumulation, inflammation and apoptosis in HepG2 cells challenged by palmitic acid (PA) combined with or without lipopolysaccharide (LPS). Finally, the reduction of hepatic fibrosis by polydatin treatment corresponded to a reduction in hepatic gene expression of fibrosis markers. Conclusions: These results suggest that polydatin prevents NASH and fibrosis via inhibition of oxidative stress and inflammation, highlighting polydatin as a potential therapeutic agent for prevention and treatment of NASH.

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) and liver fibrosis: A review

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs) are key producer of reactive oxygen species in liver cells. Hepatic stellate cells (HSCs) and Kupffer cells (KCs) are the two key cells for expression of NOX in liver. KCs produce only NOX2, while HSCs produce NOX1, 2, and 4, all of which play essential roles in the process of fibrogenesis within liver. These NOX subtypes are contributed to induction of liver fibrosis by acting through multiple pathways including induction of HSC activation, proliferation, survival and migration, stimulation of hepatocyte apoptosis, enhancement of fibrogenic mediators, and mediation of an inflammatory cascade in both KCs and HSCs.

SIGNIFICANCE

KCs and HSCs are two key cells for production of NOX in liver in relation to the pathology of liver fibrosis. NOX subtypes 1, 2, and 4 are inducers of fibrogenesis in liver. NOX activation favors hepatocyte apoptosis, HSC activation, and KC-mediated inflammatory cascade in liver, all of which are responsible for generation of liver fibrosis.

Protective effects of polydatin and grape seed extract in rats exposed to cadmium

The current study aimed to investigate the protective role of polydatin (PD) and grape seed extracts (GSEs) against the effects of cadmium chlorine (CD) application in the rats. Forty-nine adult Wistar albino male rats were used in the study. Rats were assigned into control (saline), CD (5 mg/kg CdCI₂), PD (120 mg/kg PD), GSE (120 mg/kg GSE), CD + PD (5 mg/kg CdCI₂ + 120 mg/kg PD), CD + GSE (5 mg/kg CdCI₂ + 120 mg GSE), and CD + PD + GSE (5 mg/kg CdCI₂+120 mg/kg PD +120 mg/kg GSE) treatments (n = 7 per group). The treatments were administered orally for four weeks. CD accumulation was observed in all tissues studied except for the brain tissue. PD and GSE inhibited CD accumulation in erythrocytes and tissues at varying levels. The liver, kidney, brain, and testes showed extensive degenerative histopathological changes in CD group. Liver total oxidant status (TOS) in the CD group increased significantly compared to the control. TOS of kidney, brain, and testis suggested that PD and GSE did not show a strong antioxidant effect in these tissues. Malondialdehyde (MDA) levels in blood and liver raised significantly in CD-treated rats compared to controls. PD, GSE, and their combinations increased antioxidant potential in all tissues and decreased MDA levels in blood plasma and liver. Overall, the protective effects of PD were more effective than GSE. Results suggested that although the initiation of histopathological changes was present in all tissues, the initiating factor was not the oxidative stress in the tissues studied except for the liver and blood.

Polydatin protects against acetaminophen-induced hepatotoxicity in mice via anti-oxidative and anti-apoptotic activities

Polydatin protects against acetaminophen-induced hepatotoxicity in mice.

Therapeutic efficacy of polydatin for nonalcoholic fatty liver disease via regulating inflammatory response in obese mice

Polydatin (PD), a natural precursor of resveratrol, has been used to treat several diseases, such as cardiovascular diseases, hepatic diseases and various cancers.