Hesperetin derivative-7 inhibits PDGF-BB-induced hepatic stellate cell activation and proliferation by targeting Wnt/β-catenin pathway

Targeting Hepatic Stellate Cells for the Prevention and Treatment of Liver Cirrhosis and Hepatocellular Carcinoma: Strategies and Clinical Translation

Hepatic stellate cells (HSC) are the major source of myofibroblasts (MFB) in fibrosis and cancer- associated fibroblasts (CAF) in both primary and metastatic liver cancer. Over the past few decades, there has been significant progress in understanding the cellular and molecular mechanisms by which liver fibrosis and HCC occur, as well as the key roles of HSC in their pathogenesis. HSC-targeted approaches using specific surface markers and receptors may enable the selective delivery of drugs, oligonucleotides, and therapeutic peptides that exert optimized anti-fibrotic and anti-HCC effects. Recent advances in omics, particularly single-cell sequencing and spatial transcriptomics, hold promise for identifying new HSC targets for diagnosing and treating liver fibrosis/cirrhosis and liver cancer.

Advancements in Plant-Based Therapeutics for Hepatic Fibrosis: Molecular Mechanisms and Nanoparticulate Drug Delivery Systems

Chronic liver injuries often lead to hepatic fibrosis, a condition characterized by excessive extracellular matrix accumulation and abnormal connective tissue hyperplasia. Without effective treatment, hepatic fibrosis can progress to cirrhosis or hepatocellular carcinoma. Current treatments, including liver transplantation, are limited by donor shortages and high costs. As such, there is an urgent need for effective therapeutic strategies. This review focuses on the potential of plant-based therapeutics, particularly polyphenols, phenolic acids, and flavonoids, in treating hepatic fibrosis. These compounds have demonstrated anti-fibrotic activities through various signaling pathways, including TGF-β/Smad, AMPK/mTOR, Wnt/β-catenin, NF-κB, PI3K/AKT/mTOR, and hedgehog pathways. Additionally, this review highlights the advancements in nanoparticulate drug delivery systems that enhance the pharmacokinetics, bioavailability, and therapeutic efficacy of these bioactive compounds. Methodologically, this review synthesizes findings from recent studies, providing a comprehensive analysis of the mechanisms and benefits of these plant-based treatments. The integration of novel drug delivery systems with plant-based therapeutics holds significant promise for developing effective treatments for hepatic fibrosis.

Chinese herbal medicines: The modulator of nonalcoholic fatty liver disease targeting oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Plants are a natural treasure trove; their secondary metabolites participate in several pharmacological processes, making them a crucial component in the synthesis of novel pharmaceuticals and serving as a reserve resource foundation in this process. Nonalcoholic fatty liver disease (NAFLD) is associated with the risk of progression to hepatitis and liver cancer. The "Treatise on Febrile Diseases," "Compendium of Materia Medica," and "Thousand Golden Prescriptions" have listed herbal remedies to treat liver diseases.

AIM OF THE REVIEW

Chinese herbal medicines have been widely used for the prevention and treatment of NAFLD owing to their efficacy and low side effects. The production of reactive oxygen species (ROS) during NAFLD, and the impact and potential mechanism of ROS on the pathogenesis of NAFLD are discussed in this review. Furthermore, common foods and herbs that can be used to prevent NAFLD, as well as the structure-activity relationships and potential mechanisms, are discussed.

METHODS

Web of Science, PubMed, CNKI database, Google Scholar, and WanFang database were searched for natural products that have been used to treat or prevent NAFLD in the past five years. The primary search was performed using the following keywords in different combinations in full articles: NAFLD, herb, natural products, medicine, and ROS. More than 400 research papers and review articles were found and analyzed in this review.

RESULTS

By classifying and discussing the literature, we obtained 86 herbaceous plants, 28 of which were derived from food and 58 from Chinese herbal medicines. The mechanism of NAFLD was proposed through experimental studies on thirteen natural compounds (quercetin, hesperidin, rutin, curcumin, resveratrol, epigallocatechin-3-gallate, salvianolic acid B, paeoniflorin, ginsenoside Rg1, ursolic acid, berberine, honokiol, emodin). The occurrence and progression of NAFLD could be prevented by natural antioxidants through several pathways to prevent ROS accumulation and reduce hepatic cell injuries caused by excessive ROS.

CONCLUSION

This review summarizes the natural products and routinely used herbs (prescription) in the prevention and treatment of NAFLD. Firstly, the mechanisms by which natural products improve NAFLD through antioxidant pathways are elucidated. Secondly, the potential of traditional Chinese medicine theory in improving NAFLD is discussed, highlighting the safety of food-medicine homology and the broader clinical potential of multi-component formulations in improving NAFLD. Aiming to provide theoretical basis for the prevention and treatment of NAFLD.

Research Progress Regarding the Effect and Mechanism of Dietary Polyphenols in Liver Fibrosis

The development of liver fibrosis is a result of chronic liver injuries may progress to liver cirrhosis and liver cancer. In recent years, liver fibrosis has become a major global problem, and the incidence rate and mortality are increasing year by year. However, there are currently no approved treatments. Research on anti-liver-fibrosis drugs is a top priority. Dietary polyphenols, such as plant secondary metabolites, have remarkable abilities to reduce lipid metabolism, insulin resistance and inflammation, and are attracting more and more attention as potential drugs for the treatment of liver diseases. Gradually, dietary polyphenols are becoming the focus for providing an improvement in the treatment of liver fibrosis. The impact of dietary polyphenols on the composition of intestinal microbiota and the subsequent production of intestinal microbial metabolites has been observed to indirectly modulate signaling pathways in the liver, thereby exerting regulatory effects on liver disease. In conclusion, there is evidence that dietary polyphenols can be therapeutically useful in preventing and treating liver fibrosis, and we highlight new perspectives and key questions for future drug development.

Hesperetin derivative decreases CCl4 -induced hepatic fibrosis by Ptch1-dependent mechanisms

Hepatic fibrosis (HF), a continuous wound-healing response of the liver to repeated injuries, is characterized by abnormal extracellular matrix (ECM) accumulation. Hepatic stellate cells (HSCs) are considered a major cell type for ECM production. However, recent evidence indicates the lack of effective treatments for HF. Hesperetin, a Traditional Chinese Medicine monomer, has been isolated from the fruit peel of Citrusaurantium L. (Rutaceae). Growing evidence suggests the partial function of hesperetin in HF treatment. A hesperetin derivative (HD) was synthesized in our laboratory to increase the bioavailability and the water solubility of hesperetin. In this study, we detected the functions of HD in a mouse model of CCl₄ -induced HF and transforming growth factor-β1-stimulated HSC-T6 cells, in vivo and in vitro. HD reduced histological damage and CCl₄ -induced HF. Moreover, HD interference was associated with the activation of indicators in HSC-T6 cells, showing that HD is involved in HSCs activation in HF. Mechanistically, the Hedgehog pathway is involved in the HD treatment of HF, and HD may attenuate the aberrant expression of patched1. In conclusion, the studies indicate that HD may function as a potential antifibrotic Traditional Chinese Medicine monomer in HF therapy.

O-alkyl and o-benzyl hesperetin derivative-1L attenuates inflammation and protects against alcoholic liver injury via inhibition of BRD2-NF-κB signaling pathway

Alcoholic liver injury (ALI) is a major risk factor for alcoholic liver disease, characterized by excessive inflammatory response and abnormal liver dysfunction. Previous studies have indicated that O-alkyl and o-benzyl hesperetin derivative-1 L (HD-1 L) has anti-inflammatory and hepato-protective effects in CCl₄-induced liver injury. However, its effect on ALI and underlying mechanism has not been elucidated. This study was designed to evaluate the protective effects of HD-1 L on alcoholic liver injury and reveal the underlying mechanisms. ALI model was established in male C57BL/6 J mice (aged 6-8 weeks) by Gao-Binge protocol. The mice were received different doses of HD-1 L (25 mg/kg, 50 mg/kg, 100 mg/kg) by daily intragastric administration, respectively. Liver function and inflammation were measured. Mechanism underlying the anti-inflammatory and hepato-protective effect of HD-1 L were studied in RAW264.7 cells. In alcoholic liver injury mice, HD-1 L effectively improved the liver pathology, and remarkably reduced the levels of alanine transaminase (ALT), aspartate transaminase (AST), triglyceride (TG) and total cholesterol (T-CHO) in serum. Moreover, HD-1 L markedly suppressed inflammation in vivo and inhibited the secretion of inflammatory factors in vitro. Our results showed that HD-1 L decreased the activity of Bromodomain-containing Protein 2 (BRD2) and inhibited expression of BRD2 in vivo and in vitro. Furthermore, HD-1 L further alleviated alcohol-induced inflammation after blocking BRD2 with inhibitor (JQ1) or BRD2 small interfering (si)-RNA in RAW264.7 cells. Besides, HD-1 L failed to effectively exert its anti-inflammatory effects after over expression of BRD2. In addition, HD-1 L significantly inhibited the phosphorylation and activation of NF-κB-P65 mediated by BRD2. In conclusion, HD-1 L alleviated liver injury and inflammation mainly by inhibiting BRD2-NF-κB signaling pathway, and HD-1 L may be a potential anti-inflammatory compound in treatment of alcoholic liver disease.

MicroRNAs in the Pathogenesis of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), or, more accurately, metabolic associated fatty liver disease, accounts for a large proportion of chronic liver disorders worldwide and is closely associated with other conditions such as cardiovascular disease, obesity, and type 2 diabetes mellitus. NAFLD ranges from simple steatosis to nonalcoholic steatohepatitis (NASH) and can progress to cirrhosis and, eventually, also hepatocellular carcinoma. The morbidity and mortality associated with NAFLD are increasing rapidly year on year. Consequently, there is an urgent need to understand the etiology and pathogenesis of NAFLD and identify effective therapeutic targets. MicroRNAs (miRNAs), important epigenetic factors, have recently been proposed to participate in NAFLD pathogenesis. Here, we review the roles of miRNAs in lipid metabolism, inflammation, apoptosis, fibrosis, hepatic stellate cell activation, insulin resistance, and oxidative stress, key factors that contribute to the occurrence and progression of NAFLD. Additionally, we summarize the role of miRNA-enriched extracellular vesicles in NAFLD. These miRNAs may comprise suitable therapeutic targets for the treatment of this condition.

Effect of Flavonoid Supplementation on Alveolar Bone Healing-A Randomized Pilot Trial

We investigated the effects of two common dietary supplements on bone healing in dental extraction sockets in humans. In this randomized pilot trial, male subjects took Grape Seed Extract [GSE] or Grapefruit Extract [GFE] starting two weeks prior to dental extraction and maintained this regimen for sixty days after surgery. Extraction sockets were filled with a collagen plug. After 24 h, a socket sample was collected and processed for quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and an 84-gene wound healing assay. Sixty days after tooth extraction, a core of newly formed bone was obtained prior to dental implant placement and processed for histology. qRT-PCR revealed that GFE led to a significant decrease in platelet-derived growth factor and interleukin (IL)1-β compared to GSE, and a significant decrease in IL-6 and CXCL2 compared to control. GSE led to a significant increase in coagulation factor Von Willebrand and inflammatory marker IL1-β compared to GFE. WISP1 and CXCL5 were upregulated in both groups. Overall, GFE showed a downregulation of inflammation and GSE led to a decrease in collagen density and increased osteoclasts. This pilot trial highlights the need for further investigation on the mechanism of action of such supplements on bone healing and oral health.

LEFTY2 alleviates hepatic stellate cell activation and liver fibrosis by regulating the TGF-β1/Smad3 pathway

Activated hepatic stellate cells (HSCs) are the major cell type involved in the deposition of extracellular matrix (ECM) during the development of hepatic fibrosis. In this study, we revealed that left-right determination factor 2 (LEFTY2), one of the proteins belonging to the transforming growth factor-β (TGF-β) protein superfamily, was remarkedly decreased in human hepatic fibrosis tissues and in a carbon tetrachloride (CCl₄)-induced liver fibrosis mouse model. In addition, TGF-β1 treatment markedly reduced the level of LEFTY2 in HSCs. Importantly, overexpression of LEFTY2 suppressed the activation and proliferation of HSCs. LEFTY2 inhibited the expression of TGF-β1-induced fibrosis-associated genes (α-SMA and COL1a1) in human (LX-2) and rat (HSC-T6) HSC cell lines in vitro. Mechanistically, we demonstrated, for the first time, the role of LEFTY2 in inhibiting TGF-β1/Smad3 signaling, suggesting that there is a mutual antagonism between LEFTY2 and TGF-β1/Smad3 signaling during liver fibrosis. Similarly, we observed that LEFTY2 has a negative effect on its downstream genes, including c-MYC, CDK4, and cyclin D1, in liver fibrosis. Collectively, our data strongly indicated that LEFTY2 plays an important role in controlling the proliferation and activation of HSCs in the progression of liver fibrosis and this could be a potential therapeutic target for its treatment.

Wnt signaling pathway in aging-related tissue fibrosis and therapies

Fibrosis is the final hallmark of pathological remodeling, which is a major contributor to the pathogenesis of various chronic diseases and aging-related organ failure to fully control chronic wound-healing and restoring tissue function. The process of fibrosis is involved in the pathogenesis of the kidney, lung, liver, heart and other tissue disorders. Wnt is a highly conserved signaling in the aberrant wound repair and fibrogenesis, and sustained Wnt activation is correlated with the pathogenesis of fibrosis. In particular, mounting evidence has revealed that Wnt signaling played important roles in cell fate determination, proliferation and cell polarity establishment. The expression and distribution of Wnt signaling in different tissues vary with age, and these changes have key effects on maintaining tissue homeostasis. In this review, we first describe the major constituents of the Wnt signaling and their regulation functions. Subsequently, we summarize the dysregulation of Wnt signaling in aging-related fibrotic tissues such as kidney, liver, lung and cardiac fibrosis, followed by a detailed discussion of its involvement in organ fibrosis. In addition, the crosstalk between Wnt signaling and other pathways has the potential to profoundly add to the complexity of organ fibrosis. Increasing studies have demonstrated that a number of Wnt inhibitors had the potential role against tissue fibrosis, specifically in kidney fibrosis and the implications of Wnt signaling in aging-related diseases. Therefore, targeting Wnt signaling might be a novel and promising therapeutic strategy against aging-related tissue fibrosis.

Hesperetin derivative attenuates CCl4-induced hepatic fibrosis and inflammation by Gli-1-dependent mechanisms

Hepatic fibrosis, a common pathological feature and leading cause of various chronic liver diseases, still lacks effective therapy. Hesperetin derivative (HD) is a derivative of Traditional Chinese Medicine monomer isolated from the fruit peel of Citrusaurantium L. (Rutaceae). In the present study, we revealed the anti-fibrotic effects of HD in CCl₄-induced mouse hepatic fibrosis model and in TGF-β1-activated LX-2 cells, in vivo and in vitro. Results showed that HD prevented CCl₄-induced liver injury and histological damage. Consistently, HD inhibited the up-regulation of liver fibrogenesis markers α-SMA, Col1α1, Col3α1 and TIMP-1 in primary hepatic stellate cells (HSCs) and suppressed inflammatory responses in primary liver macrophages from hepatic fibrosis mice. Furthermore, HD promoted the apoptosis of activated HSCs, a key step in the onset of fibrosis regression. Mechanistically, the Hedgehog pathway was involved in HD-treated hepatic fibrosis, and HD specifically contributed to attenuate the aberrant expression of Glioma associated oncogene-1 (Gli-1). Interestingly, blockade of Gli-1 removed the inhibitory effect of HD on activated HSCs, indicating that Gli-1 may play a pivotal role in mediating the anti-fibrotic effect of HD in hepatic fibrosis. Collectively, our results suggest that HD may be a potential anti-fibrotic Traditional Chinese Medicine monomer for the treatment of hepatic fibrosis.

Plantamajoside exerts antifibrosis effects in the liver by inhibiting hepatic stellate cell activation

The pathogenesis of liver fibrosis involves the activation of hepatic stellate cells (HSCs) into muscle fiber cells and fibroblasts. The aim of the current study was to investigate whether plantamajoside (PMS) exerted antifibrosis effects by affecting HSCs activation and survival during liver fibrosis, and to investigate the underlying mechanism. HSC-T6 cells were activated by exposure to platelet-derived growth factor BB (PDGF-BB), and were subsequently treated with increasing concentrations of PMS (0, 20, 40, 80 and 160 µg/ml). Cell viability, apoptosis, migration and invasion were determined using the Cell Counting Kit-8 (CCK-8) assay, flow cytometry and the Transwell assay, respectively. Results indicated that PDGF-BB significantly activated HSC-T6 cells, demonstrated by increased cell proliferation, enhanced cell migration and invasion as well as increased expression of α-smooth muscle actin (α-SMA) and collagen type 1 α 1 (Col1α1). PMS inhibited proliferation, induced cell apoptosis and prevented cell migration and invasion in PDGF-BB-treated HSC-T6 cells in what appeared to be a dose-dependent manner. PMS appeared to dose-dependently reduce the protein and mRNA levels of α-SMA and Col1α1 in PDGF-BB-treated HSC-T6 cells. Furthermore, the results of the present study suggested that PMS administration inhibited the protein expression of phosphorylated-protein kinase B in what appeared to be a dose-dependent manner. In conclusion, the data indicated that PMS exhibited an antifibrotic effect in the liver by inhibiting hepatic stellate cell activation and survival.

Research progress on the anti-hepatic fibrosis action and mechanism of natural products

Hepatic fibrosis is the most common pathological feature of most chronic liver diseases, and its continuous deterioration gradually develops into liver cirrhosis and eventually leads to liver cancer. At present, there are many kinds of drugs used to treat liver fibrosis. However, Western drugs tend to only target single genes/proteins and induce many adverse reactions. Most of the mechanisms and active ingredients of traditional Chinese medicine (TCM) are not clear, and there is a lack of unified diagnosis and treatment standards. Natural products, which are characterized by structural diversity, low toxicity, and origination from a wide range of sources, have unique advantages and great potential in anti-liver fibrosis. This article summarizes the work done over the previous decade, on the active ingredients in natural products that are reported to have anti-hepatic fibrosis effects. The effective anti-hepatic fibrosis ingredients identified can be generally divided into flavonoids, saponins, polysaccharides and alkaloids. Mechanisms of anti-liver fibrosis include inhibition of liver inflammation, anti-lipid peroxidation injury, inhibition of the activation and proliferation of hepatic stellate cells (HSCs), modulation of the synthesis and secretion of pro-fibrosis factors, and regulation of the synthesis and degradation of the extracellular matrix (ECM). This review provides suggestions for the development of anti-hepatic fibrosis drugs.

4-Methylcoumarin-[5,6-g]-hesperetin attenuates inflammatory responses in alcoholic hepatitis through PPAR-γ activation

4-Methylcoumarin-[5,6-g]-hesperetin (4-MCH) is a hesperidin derivative produced by the structural modification of hesperetin. Alcoholic hepatitis (AH) is the origin of many serious liver diseases that are accompanied by hepatic inflammation. In this study, we detected the anti-inflammatory activity of 4-MCH in EtOH fed mice and examined the potential molecular mechanism of this activity. We found that 4-MCH suppressed the release of inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in primary liver macrophages isolated from mice and in EtOH-treated RAW264.7 cells. In addition, we showed that the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) was down-regulated in vivo and in vitro in AH. Furthermore, 4-MCH acted as an activator of PPAR-γ, which could therefore ameliorate the inhibitory effects of EtOH on the expression of PPAR-γ. The impairment of PPAR-γ function (T0070907 or PPAR-γ siRNA treatment) resulted in greater inflammation than that in the control group. Conversely, over-expression of PPAR-γ further reduced the release of inflammatory cytokines from EtOH-stimulated RAW264.7 cells. Additional investigations showed that 4-MCH significantly inhibited the phosphorylation of p65. Collectively, these results indicate that 4-MCH alleviated the inflammatory reaction through PPAR-γ activation via the NF-κB-p65 signaling pathway, which regulates the expression of IL-6 and TNF-α in AH.

Endostatin inhibits fibrosis by modulating the PDGFR/ERK signal pathway: an in vitro study

Accumulating evidence indicates that endostatin inhibits fibrosis. However, the mechanism is yet to be clarified. The aim of this study is to evaluate the effect of endostatin on platelet-derived growth factor-BB (PDGF-BB)- or transforming growth factor β1 (TGF-β1)-induced fibrosis in cultured human skin fibroblasts, and to further examine the molecular mechanisms involved. Human dermal fibroblasts were cultured in Dulbecco's modified Eagle's medium (DMEM) and serum-starved for 48 h before treatment. Cells were grouped as follows: "PDGF-BB", "PDGF-BB+ endostatin", "TGF-β1", "TGF-β1+endostatin", "endostatin", and "blank control". The fibroblasts were stimulated with either TGF-β1 or PDGF-BB for 72 h in order to set up the fibrosis model in vitro. The cells were co-cultured with either TGF-β1 or PDGF-BB and endostatin and were used to check the inhibiting effect of endostatin. A blank control group and an endostatin group were used as negative control groups. The biomarkers of fibrosis, including the expression of collagen I, hydroxyproline, and α-smooth muscle actin (α-SMA), were evaluated using an enzyme-linked immunosorbent assay (ELISA) and Western blot. The expression of phosphorylated PDGF receptor β (p-PDGFRβ), PDGFRβ, phosphorylated extracellular signal-regulated kinase (p-ERK), and ERK was detected using Western blot and immunofluorescent staining was used to explore the mechanisms. Both PDGF-BB and TGF-β1 significantly up-regulated the expression of collagen I, hydroxyproline, and α-SMA. Endostatin significantly attenuated both the PDGF-BB- and TGF-β1-induced over-expression of collagen I, hydroxyproline, and α-SMA. PDGF-BB and TGF-β1 both promoted the expression of PDGFR, ERK, and p-ERK. Endostatin inhibited the expression of PDGFR and p-ERK but did not affect the expression of total ERK. Endostatin inhibited hypertrophic scar by modulating the PDGFRβ/ERK pathway. Endostatin could be a promising multi-target drug in future fibrosis therapy.

Overexpression of C‑sis inhibits H2O2‑induced Buffalo rat liver cell apoptosis in vitro and alleviates liver injury in a rat model of fulminant hepatic failure

The present study aimed to investigate the role of the C‑sis gene in the apoptosis of hepatocytes in vitro and in the liver function of a rat model of fulminant hepatic failure (FHF). Buffalo rat liver (BRL) cells were treated with hydrogen peroxide (H2O2) to induce apoptosis and then transfected with a C‑sis overexpression vector. A rat model of FHF was established, and C‑sis was overexpressed. The mRNA and protein expression of C‑sis were examined using reverse transcription‑polymerase chain reaction and western blot analyses, respectively. Cell viability was assessed by CCK8, and a TUNEL assay was used to examine cell apoptosis. Flow cytometry was used for cell cycle detection. Hematoxylin and eosin staining was used for histological examination. The levels of alanine transaminase (ALT) and aspartate transaminase (AST) were also examined in the rats. The results showed that C‑sis was successfully overexpressed in the cells and rat model. Compared with H2O2‑treated BRL cells, the overexpression of C‑sis significantly inhibited cell apoptosis, promoted cell viability, and decreased the expression of cleaved caspase-3. Similar results were observed in the FHF rats treated with the C‑sis overexpression plasmid, compared with those treated with empty plasmids. In addition, in the FHF rats overexpressing C‑sis, histological examination showed that liver injury was alleviated, the levels of ALT and AST were significantly decreased, and mortality rate was significantly decreased, compared with those observed in the rats treated with empty plasmids. In conclusion, the overexpression of C‑sis inhibited the H2O2‑induced apoptosis of BRL cells in vitro, and alleviated liver injury, improved liver function, and decreased mortality rates in rat models of FHF.

Emerging role and therapeutic implication of Wnt signaling pathways in liver fibrosis

Activation of hepatic stellate cells (HSCs) is a pivotal cellular event in liver fibrosis. Therefore, improving our understanding of the molecular pathways that are involved in these processes is essential to generate new therapies for liver fibrosis. Greater knowledge of the role of the Wnt signaling pathway in liver fibrosis could improve understanding of the liver fibrosis pathogenesis. The aim of this review is to describe the present knowledge about the Wnt signaling pathway, which significantly participates in liver fibrosis and HSC activation, and look ahead on new perspectives of Wnt signaling pathway research. Moreover, we will discuss the different interactions with Wnt signaling pathway-regulated liver fibrosis. The Wnt signaling pathway modulates several important aspects of function, including cell proliferation, activation and differentiation. Targeting the Wnt signaling pathway can be a promising direction in liver fibrosis treatment. We discuss new perspectives of Wnt signaling pathway activation in liver fibrosis. For example, antagonist to Wnt and Wnt ligands could inhibit liver fibrosis by regulating Wnt/β-catenin signaling pathway. These findings identify the Wnt signaling pathway as a potentially important for therapeutic targets in liver fibrosis. Future studies are needed in order to find safer and more effective Wnt-based drugs.

Baicalin inhibits PDGF-BB-induced hepatic stellate cell proliferation, apoptosis, invasion, migration and activation via the miR-3595/ACSL4 axis

Hepatic fibrosis is a physiological response to liver injury that includes a range of cell types. The pathogenesis of hepatic fibrosis currently focuses on hepatic stellate cell (HSC) activation into muscle fiber cells and fibroblasts. Baicalin is a flavone glycoside. It is the glucuronide of baicalein, which is extracted from the dried roots of Scutellaria baicalensis Georgi. Previous work focused on the anti-viral, -inflammatory and -tumor properties of baicalin. However, the potential anti-fibrotic effects and mechanisms of baicalin are not known. The present study demonstrated that baicalin influenced the activation, proliferation, apoptosis, invasion and migration of platelet-derived growth factor-BB-induced activated HSC-T6 cells in a dose-dependent manner. To investigate the anti-fibrotic effect of baicalin, a one-color micro (mi)RNA array and reverse transcription-quantitative polymerase chain reaction analyses were used. Results demonstrated that baicalin increased the expression of the miRNA, miR-3595. In addition, the inhibition of miR-3595 substantially reversed the anti-fibrotic effect of baicalin. The present data also suggested that miR-3595 negatively regulates the long-chain-fatty-acid-CoA ligase 4 (ACSL4). Furthermore, ACSL4 acted in a baicalin-dependent manner to exhibit anti-fibrotic effects. Taken together, it was concluded that baicalin induces miR-3595 expression that modulates the expression levels of ACSL4. To the best of our knowledge, the present study is the first to demonstrate that baicalin induces overexpression of human miR-3595, and subsequently decreases the expression of ACSL4, resulting in an anti-fibrotic effect.

Hesperetin alleviates renal interstitial fibrosis by inhibiting tubular epithelial-mesenchymal transition in vivo and in vitro

Hesperetin (HES) is a flavonoid that has been reported to exert protective effects against cardiac remodeling, lung fibrosis and hepatic fibrosis. However, reports on the effects and potential mechanisms of HES in renal fibrosis are limited. In the present study, a unilateral ureteric obstruction (UUO) mouse model and a transforming growth factor (TGF)-β1-activated normal rat kidney (NRK)-52E cell model were established. HES was subsequently administered to these models to evaluate its anti-fibrotic effects and potential underlying mechanisms of action. The results demonstrated that HES reduced obstruction-induced renal injury and deposition of the extracellular matrix components collagen-I and fibronectin in UUO mouse kidneys (P<0.05). Furthermore, HES treatment significantly suppressed EMT, as evidenced by decreased expression of α-smooth muscle actin and E-cadherin, (P<0.05). Additionally, HES inhibited the hedgehog signaling pathway in UUO mice and TGF-β1-treated NRK-52E cells. The present findings indicate that HES treatment may inhibit EMT and renal fibrosis in vivo and in vitro by antagonizing the hedgehog signaling pathway.

Design, synthesis and biological evaluation of hesperetin derivatives as potent anti-inflammatory agent

A flavonoid hesperetin is reported to have a variety of biological activities, including anticancer, antiviral, antioxidant, neuroprotective and anti-inflammatory properties. Thirty-one novel hesperetin derivatives were designed, synthesized and evaluated for anti-inflammatory activity using RAW264.7 cells and CCl4-induced acute liver injury model. Among these compounds, 5b displayed the excellent anti-inflammatory activity on decreasing NO, IL-6 and TNF-α both in vitro and vivo. In addition, 5b could also reduce the release of NO, IL-6 and TNF-α production by LPS stimulated RAW 264.7 cell through MAPK and NF-κB signaling pathway in a concentration dependent manner. From in vivo study, it was also observed that 5b attenuated liver histopathologic changes in mouse models.

Silencing of α-complex protein-2 reverses alcohol- and cytokine-induced fibrogenesis in hepatic stellate cells

BACKGROUND AND AIM

α-complex protein-2 (αCP2) encoded by the poly (rC) binding protein 2(PCBP2) gene is responsible for the accumulation of type I collagen in fibrotic livers. In this study, we silenced the PCBP2 gene using a small interfering RNA (siRNA) to reverse alcohol-and cytokine-induced profibrogenic effects on hepatic stellate cells (HSCs).

METHODS

Primary rat HSCs and the HSC-T6 cell line were used as fibrogenic models to mimic the initiation and perpetuation stages of fibrogenesis, respectively. We previously found that a PCBP2 siRNA, which efficiently silences expression of αCP2, reduces the stability of type I collagen mRNA. We investigated the effects of the PCBP2 siRNA on cell proliferation and migration. Expression of type I collagen in HSCs was analyzed by quantitative real-time PCR and western blotting. In addition, we evaluated the effects of the PCBP2 siRNA on apoptosis and the cell cycle.

RESULTS

PCBP2 siRNA reversed multiple alcohol- and cytokine-induced profibrogenic effects on primary rat HSCs and HSC-T6 cells. The PCBP2 siRNA also reversed alcohol- and cytokine-induced accumulation of type I collagen as well as cell proliferation and migration. Moreover, the combination of LY2109761, a transforming growth factor-β1 inhibitor, and the PCBP2 siRNA exerted a synergistic inhibitive effect on the accumulation of type I collagen in HSCs.

CONCLUSIONS

Silencing of PCBP2 using siRNA could be a potential therapeutic strategy for alcoholic liver fibrosis.

EZH2-mediated repression of Dkk1 promotes hepatic stellate cell activation and hepatic fibrosis

EZH2, a histone H3 lysine‐27‐specific methyltransferase, is involved in diverse physiological and pathological processes including cell proliferation and differentiation. However, the role of EZH2 in liver fibrosis is largely unknown. In this study, it was identified that EZH2 promoted Wnt pathway‐stimulated fibroblasts in vitro and in vivo by repressing Dkk‐1, which is a Wnt pathway antagonist. The expression of EZH2 was increased in CCl₄‐induced rat liver and primary HSCs as well as TGF‐β1‐treated HSC‐T6, whereas the expression of Dkk1 was reduced. Silencing of EZH2 prevented TGF‐β1‐induced proliferation of HSC‐T6 cells and the expression of α‐SMA. In addition, knockdown of Dkk1 promoted TGF‐β1‐induced activation of HSCs. Moreover, silencing of EZH2 could restore the repression of Dkk‐1 through trimethylation of H3K27me3 in TGF‐β1‐treated HSC‐T6 cells. Interestingly, inhibition of EZH2 had almost no effect on the activation of HSC when Dkk1 was silenced. Collectively, EZH2‐mediated repression of Dkk1 promotes the activation of Wnt/β‐catenin pathway, which is an essential event for HSC activation.

Mechanisms and treatment of liver fibrosis

Hepatic fibrosis is a characteristic consequence of multiple chronic liver injuries. However, there are currently no specific drugs that can effectively reverse or prevent liver fibrosis progression. Liver fibrosis is a complex pathological process attributable to a variety of cytokines and molecular pathways. Therefore, further exploring the cellular and molecular mechanisms of liver fibrosis, unearthing specific anti-fibrosis targeted therapies and translation of the potential findings into clinical treatment are of great significance.

Intestinal transport of HDND-7, a novel hesperetin derivative, in in vitro MDCK cell and in situ single-pass intestinal perfusion models

1. Hesperetin (HDND) possesses extensive bioactivities, however, its poor solubility and low bioavailability limit its application. HDND-7, a derivative of HDND, has better solubility and high bioavailability. In this study, we investigated the intestinal absorption mechanisms of HDND-7. 2. MDCK cells were used to examine the transport mechanisms of HDND-7 in vitro, and a rat in situ intestinal perfusion model was used to characterize the absorption of HDND-7. The concentration of HDND-7 was determined by HPLC. 3. In MDCK cells, HDND-7 was effectively absorbed in a concentration-dependent manner in both directions. Moreover, HDND-7 showed pH-dependent and TEER-independent transport in both directions. The transport of HDND-7 was significantly reduced at 4 °C or in the presence of NaN3. Furthermore, the efflux of HDND-7 was apparently reduced in the presence of MRP2 inhibitors MK-571 or probenecid. However, P-gp inhibitor verapamil had no effect on the transport of HDND-7. The in situ intestinal perfusion study indicated HDND-7 was well-absorbed in four intestinal segments. Furthermore, MRP2 inhibitors may slightly increase the absorption of HDND-7 in jejunum. 4. In summary, all results indicated that HDND-7 might be absorbed mainly by passive diffusion via transcellular pathway, MRP2 but P-gp may participate in the efflux of HDND-7.

Natural antioxidants for non-alcoholic fatty liver disease: molecular targets and clinical perspectives

Non-alcoholic steatohepatitis (NASH), the progressive form of non-alcoholic fatty liver disease (NAFLD), is emerging as a main health problem in industrialized countries. Lifestyle modifications are effective in the treatment of NAFLD; however, the long-term compliance is low. Therefore, several pharmacological treatments have been proposed but none has shown significant efficacy or long-term safety. Natural polyphenols are a heterogeneous class of polyphenolic compounds contained in vegetables, which are being proposed for the treatment of different metabolic disorders. Although the beneficial effect of these compounds has traditionally related to their antioxidant properties, they also exert several beneficial effects on hepatic and extra-hepatic glucose and lipid homeostasis. Furthermore, natural polyphenols exert antifibrogenic and antitumoural effects in animal models, which appear relevant from a clinical point of view because of the association of NASH with cirrhosis and hepatocellular carcinoma. Several polyphenols, such anthocyanins, curcumin and resveratrol and those present in coffee, tea, soy are available in the diet and their consumption can be proposed as part of a healthy diet for the treatment of NAFLD. Other phenolic compounds, such as silymarin, are commonly consumed worldwide as nutraceuticals or food supplements. Natural antioxidants are reported to have beneficial effects in preclinical models of NAFLD and in pilot clinical trials, and thus need clinical evaluation. In this review, we summarize the existing evidence regarding the potential role of natural antioxidants in the treatment of NAFLD and examine possible future clinical applications.

Targeting pancreatic cancer using a combination of gemcitabine with the omega-3 polyunsaturated fatty acid emulsion, Lipidem™

SCOPE

Pancreatic cancer remains a disease of poor prognosis, with alternate strategies being sought to improve therapeutic efficacy. Omega-3 fatty acids have shown clinical benefit, and mechanisms of action are under investigation.

METHODS AND RESULTS

Proliferation assays, flow cytometry, invasion assays, ELISA and western blotting were used to investigate efficacy of omega-3 fatty acids alone and in combination with gemcitabine. The docosahexanoic acid (DHA)/eicosapentanoic acid (EPA) combination, Lipidem™, in combination with gemcitabine inhibited growth in pancreatic cancer and pancreatic stellate cell (PSC) lines, with PSCs exhibiting greatest sensitivity to this combination. Invasion of pancreatic cancer cells and PSCs in a 3D spheroid model, was inhibited by combination of gemcitabine with Lipidem™. PSCs were required for cancer cell invasion in an organotypic co-culture model, with invasive capacity reduced by Lipidem™ alone. Platelet-derived growth factor (PDGF) is a key cytokine in pro-proliferative and invasion signalling, and thus a critical regulator of interactions between pancreatic cancer cells and adjacent stroma. Platelet-derived growth factor (PDGF-BB) secretion was completely inhibited by the combination of Lipidem™ with gemcitabine in cancer cells and PSCs.

CONCLUSION

Lipidem™ in combination with gemcitabine, has anti-proliferative and anti-invasive efficacy in vitro, with pancreatic stellate cells exhibiting the greatest sensitivity to this combination.

Non-coding RNA-mediated epigenetic regulation of liver fibrosis

Hepatic stellate cells (HSC) activation plays a key role in liver fibrosis. Numerous studies have indicated that non-coding RNAs (ncRNAs) control liver fibrosis and fibroblasts proliferation. Greater knowledge of the role of the ncRNAs-mediated epigenetic mechanism in liver fibrosis could improve understanding of the liver fibrosis pathogenesis. The aim of this review is to describe the present knowledge about the ncRNAs significantly participating in liver fibrosis and HSC activation, and look ahead on new perspectives of ncRNAs-mediated epigenetic mechanism research. Moreover, we will discuss examples of non-coding RNAs that interact with histone modification or DNA methylation to regulate gene expression in liver fibrosis. Diverse classes of ncRNAs, ranging from microRNAs (miRs) to long non-coding RNAs (LncRNAs), have emerged as key regulators of several important aspects of function, including cell proliferation, activation, etc. In addition, recent advances suggest the important role of ncRNAs transcripts in epigenetic gene regulation. Targeting the miRs and LncRNAs can be a promising direction in liver fibrosis treatment. We discuss new perspectives of miRs and LncRNAs in liver fibrosis and HSC activation, mainly including interaction with histone modification or DNA methylation to regulate gene expression. These epigenetic mechanisms form powerful ncRNAs surveillance systems that may represent new targets for liver fibrosis therapeutic intervention.