Sulforaphane inhibits the activation of hepatic stellate cell by miRNA-423-5p targeting suppressor of fused

Abnormal metabolism in hepatic stellate cells: Pandora's box of MAFLD related hepatocellular carcinoma

Metabolic associated fatty liver disease (MAFLD) is a significant risk factor for the development of hepatocellular carcinoma (HCC). Hepatic stellate cells (HSCs), as key mediators in liver injury response, are believed to play a crucial role in the repair process of liver injury. However, in MAFLD patients, the normal metabolic and immunoregulatory mechanisms of HSCs become disrupted, leading to disturbances in the local microenvironment. Abnormally activated HSCs are heavily involved in the initiation and progression of HCC. The metabolic disorders and abnormal activation of HSCs not only initiate liver fibrosis but also contribute to carcinogenesis. In this review, we provide an overview of recent research progress on the relationship between the abnormal metabolism of HSCs and the local immune system in the liver, elucidating the mechanisms of immune imbalance caused by abnormally activated HSCs in MAFLD patients. Based on this understanding, we discuss the potential and challenges of metabolic-based and immunology-based mechanisms in the treatment of MAFLD-related HCC, with a specific focus on the role of HSCs in HCC progression and their potential as targets for anti-cancer therapy. This review aims to enhance researchers' understanding of the importance of HSCs in maintaining normal liver function and highlights the significance of HSCs in the progression of MAFLD-related HCC.

Autophagy affects hepatic fibrosis progression by regulating macrophage polarization and exosome secretion

BACKGROUND

In this study, the role of autophagy in hepatic fibrosis and its effects on macrophage polarization and exosomes (EVs) were verified by establishing hepatic fibrosis model and co-culture model, providing evidence for treatment.

METHODS

In this study, CCL₄ was used to establish hepatic fibrosis model. The morphology and purity of exosomes (EVs) were verified by transmission electron microscopy, western blotting (WB), and nanoparticle tracing analysis (NTA). Real-time quantitative PCR (qRT-PCR), WB and enzyme-linked immunoadsorption (ELISA) were used to detect hepatic fibrosis markers, macrophage polarization markers and liver injury markers. Histopathological assays were used to verify the liver injury morphology in different groups. The cell co-culture model and hepatic fibrosis model were constructed to verify the expression of miR-423-5p.

RESULTS

Hepatic fibrosis model showed that CCL₄ promoted early autophagy increase but inhibited autophagy flux in liver. mRFP-GFP-LC3 detection showed that both LPS group and Baf group inhibited autophagy flux. This inhibitory effect was reversed by Rap combination therapy. The M1/M2 markers of macrophage polarization were further tested, and it was found that LPS and Baf could promote M1 polarization and inhibit M2 polarization. Rap processing reverses this phenomenon. These data suggest that autophagy can regulate the polarization process of liver macrophages. WB and NTA showed that LPS induced EVs generation. In addition, LPS-induced EVs could promote HSC proliferation, cell cycle, migration, and the expression of fibrosis markers. Macrophage-EVs could affect the fibrosis process of stellate cells through the secretion of miR-423a-5p expression. The hepatic fibrosis model was further established to verify the regulation of autophagy and EVs on the fibrosis process.

CONCLUSION

This study was showed that autophagy could regulate fibrosis by promoting HSC activation by regulating macrophage polarization and exosome secretion.

Huangqi Decoction, a compound Chinese herbal medicine, inhibits the proliferation and activation of hepatic stellate cells by regulating the long noncoding RNA-C18orf26-1/microRNA-663a/transforming growth factor-β axis

OBJECTIVE

Huangqi Decoction (HQD), a classical traditional Chinese medicine formula, has been used as a valid treatment for alleviating liver fibrosis; however, the underlying molecular mechanism is still unknown. Although our previous studies showed that microRNA-663a (miR-663a) suppresses the proliferation and activation of hepatic stellate cells (HSCs) and the transforming growth factor-β/small mothers against decapentaplegic (TGF-β/Smad) pathway, whether long noncoding RNAs (lncRNAs) are involved in HSC activation via the miR-663a/TGF-β/Smad signaling pathway has not yet reported. The present study aimed to investigate the roles of lncRNA lnc-C18orf26-1 in the activation of HSCs and the mechanism by which HQD inhibits hepatic fibrosis.

METHODS

The expression levels of lnc-C18orf26-1, miR-663a and related genes were measured by quantitative reverse transcription-polymerase chain reaction. HSCs were transfected with the miR-663a mimic or inhibitor and lnc-C18orf26-1 small interfering RNAs. The water-soluble tetrazolium salt-1 assay was used to assess the proliferation rate of HSCs. Changes in lncRNA expression were evaluated in miR-663a-overexpressing HSCs by using microarray to identify miR-663a-regulated lncRNAs. RNA hybrid was used to predict the potential miR-663a binding sites on lncRNAs. Luciferase reporter assays further confirmed the interaction between miR-663a and the lncRNA. The expression levels of collagen α-2(I) chain (COL1A2), α-smooth muscle actin (α-SMA) and TGF-β/Smad signaling pathway-related proteins were determined using Western blotting.

RESULTS

Lnc-C18orf26-1 was upregulated in TGF-β1-activated HSCs and competitively bound to miR-663a. Knockdown of lnc-C18orf26-1 inhibited HSC proliferation and activation, downregulated TGF-β1-stimulated α-SMA and COL1A2 expression, and inhibited the TGF-β1/Smad signaling pathway. HQD suppressed the proliferation and activation of HSCs. HQD increased miR-663a expression and decreased lnc-C18orf26-1 expression in HSCs. Further studies showed that HQD inhibited the expression of COL1A2, α-SMA, TGF-β1, TGF-β type I receptor (TGF-βRI) and phosphorylated Smad2 (p-Smad2) in HSCs, and these effects were reversed by miR-663a inhibitor treatment.

CONCLUSION

Our study identified lnc-C18orf26-1 and miR-663a as promising therapeutic targets for hepatic fibrosis. HQD inhibits HSC proliferation and activation at least partially by regulating the lnc-C18orf26-1/miR-663a/TGF-β1/TGF-βRI/p-Smad2 axis.

Exosomes released by melanocytes modulate fibroblasts to promote keloid formation: a pilot study

Keloids are a common type of pathological scar as a result of skin healing, which are extremely difficult to prevent and treat without recurrence. The pathological mechanism of keloids is the excessive proliferation of fibroblasts, which synthesize more extracellular matrices (ECMs), including type I/III collagen (COL-1/3), mucopolysaccharides, connective tissue growth factor (CTGF, also known as cellular communication network factor 2 (CCN2)), and fibronectin (FN) in scar tissue, mostly through the abnormal activation of transforming growth factor-‍β (TGF-‍β)/Smads pathway (Finnson et al., 2013; Song et al., 2018). Genetic factors, including race and skin tone, are considered to contribute to keloid formation. The reported incidence of keloids in black people is as high as 16%, whereas white people are less affected. The prevalence ratio of colored people to white people is 5:1‍‍-‍‍15:1 (Rockwell et al., 1989; LaRanger et al., 2019). In addition, keloids have not been reported in albinism patients of any race, and those with darker skin in the same race are more likely to develop this disease (LaRanger et al., 2019). Skin melanocyte activity is significantly different among people with different skin tones. The more active the melanocyte function, the more melanin is produced and the darker the skin. Similarly, in the same individual, the incidence of keloids increases during periods when melanocytes are active, such as adolescence and pregnancy. Keloids rarely appear in areas where melanocytes synthesize less melanin, such as in the palms and soles. Thus, the formation of keloids seems to be closely related to melanocyte activity.

Extracellular Vesicular Transmission of miR-423-5p from HepG2 Cells Inhibits the Differentiation of Hepatic Stellate Cells

Liver fibrosis (LF) is a major cause of morbidity and mortality worldwide. Hepatic stellate cells (HSCs) are the primary source of extracellular matrix in the liver and their activation is a central event in LF development. Extracellular vesicles (EVs) are intercellular communication agents, which play important roles in physiological processes in chronic liver diseases. The aim of this study was to examine the crosstalk between hepatocytes and HSCs mediated by hepatocyte-secreted EVs. EVs were purified from primary mouse hepatocytes, HepG2 cell lines, under normal or stressed conditions. The effect of EVs on primary HSCs (pHSCs) differentiation was evaluated by measuring of differentiation markers. In addition, their impact on the carbon tetrachloride (CCl4)-induced fibrosis mouse model was evaluated. The results demonstrated that HepG2-EVs regulate HSC differentiation and that under stress conditions, promoted pHSCs differentiation into the myofibroblast phenotype. The evaluation of miRNA sequences in the HepG2 secreted EVs demonstrated high levels of miR-423-5p. The examination of EV cargo following stress conditions identified a significant reduction of miR-423-5p in HepG2-EVs relative to HepG2-EVs under normal conditions. In addition, pHSCs transfected with miR-423-5p mimic and exhibit lower mRNA levels of alpha smooth muscle actin and Collagen type 1 alpha, and the mRNA expression level of genes targeted the family with sequence-similarity-3 (FAM3) and Monoacylglycerol lipase (Mgll). This study strengthened the hypothesis that EVs are involved in LF and that their cargo changes in stress conditions. In addition, miR-423-5p was shown to be involved in HSCs differentiation and hence, fibrosis development.

Influence of the Bioactive Diet Components on the Gene Expression Regulation

Diet bioactive components, in the concept of nutrigenetics and nutrigenomics, consist of food constituents, which can transfer information from the external environment and influence gene expression in the cell and thus the function of the whole organism. It is crucial to regard food not only as the source of energy and basic nutriments, crucial for living and organism development, but also as the factor influencing health/disease, biochemical mechanisms, and activation of biochemical pathways. Bioactive components of the diet regulate gene expression through changes in the chromatin structure (including DNA methylation and histone modification), non-coding RNA, activation of transcription factors by signalling cascades, or direct ligand binding to the nuclear receptors. Analysis of interactions between diet components and human genome structure and gene activity is a modern approach that will help to better understand these relations and will allow designing dietary guidances, which can help maintain good health.

Sulforaphane ameliorates ethanol plus carbon tetrachloride-induced liver fibrosis in mice through the Nrf2-mediated antioxidant response and acetaldehyde metabolization with inhibition of the LPS/TLR4 signaling pathway

Alcoholic liver disease (ALD)-related fibrosis results from a variety of mechanisms including the accumulation of acetaldehyde, reactive oxygen species, and hepatic overload of endogenous lipopolysaccharide (LPS). Alcohol cessation is the therapeutic mainstay for patients with all stages of ALD, whereas pharmacological strategies for liver fibrosis have not been established. Sulforaphane, a phytochemical found in cruciferous vegetables, activates nuclear factor erythroid 2-related factor 2 (Nrf2) and exerts anticancer, antidiabetic, and antimicrobial effects; however, few studies investigated its efficacy in the development of ALD-related fibrosis. Herein, we investigated the effect of sulforaphane on acetaldehyde metabolism and liver fibrosis in HepaRG and LX-2 cells, human hepatoma and hepatic stellate cell lines, respectively, as well as in a mouse model of alcoholic liver fibrosis induced by ethanol plus carbon tetrachloride (EtOH/CCl₄). Sulforaphane treatment induced the activity of acetaldehyde-metabolizing mitochondrial aldehyde dehydrogenase in HepaRG cells and suppressed the acetaldehyde-induced proliferation and profibrogenic activity in LX-2 cells with upregulation of Nrf2-regulated antioxidant genes, including HMOX1, NQO1, and GSTM3. Moreover, sulforaphane attenuated the LPS/toll-like receptor 4-mediated sensitization to transforming growth factor-β with downregulation of NADPH oxidase 1 (NOX1) and NOX4. In EtOH/CCl₄-treated mice, oral sulforaphane administration augmented hepatic acetaldehyde metabolism. Additionally, sulforaphane significantly inhibited Kupffer cell infiltration and fibrosis, decreased fat accumulation and lipid peroxidation, and induced Nrf2-regulated antioxidant response genes in EtOH/CCl₄-treated mice. Furthermore, sulforaphane treatment blunted hepatic exposure of gut-derived LPS and suppressed hepatic toll-like receptor 4 signaling pathway. Taken together, these results suggest sulforaphane as a novel therapeutic strategy in ALD-related liver fibrosis.

Downregulation of miR‑141 deactivates hepatic stellate cells by targeting the PTEN/AKT/mTOR pathway

The activation of hepatic stellate cells (HSCs) caused by stimulating factors or fibrogenic cytokines is the critical stage of liver fibrosis. Recent studies have demonstrated the influence of microRNAs (miRNAs or miRs) on HSC activation and transformation; however, the function and underlying mechanisms of miRNAs in HSC activation have not yet been completely clarified. In the present study, transforming growth factor β1 (TGF‑β1) was used to treat human HSC lines (HSC‑T6 and LX2 cells) to simulate the activation of HSCs in vivo and whether the expression of miRNAs in HSCs was affected by TGF‑β1 treatment was examined using a miRNA microarray. It was observed that miR‑141 was one of the most upregulated miRNAs during HSC activation. Functional analyses revealed that miR‑141 knockdown suppressed the viability of HSCs and inhibited the expression levels of pro‑fibrotic markers. In addition, phosphatase and tensin homolog (PTEN), a well‑known suppressor of the AKT/mammalian target of rapamycin (mTOR) pathway, was found to be directly targeted by miR‑141 in HSCs. More importantly, the knockdown of PTEN markedly reversed the suppressive effects of miR‑141 inhibition on the viability of and the expression levels of pro‑fibrotic markers during HSC activation. Finally, it was observed that the downregulation of miR‑141 blocked the TGF‑β1‑induced activation of the AKT/mTOR pathway in HSCs. On the whole, the findings of the present study indicate that miR‑141 inhibition suppresses HSC activation via the AKT/mTOR pathway by targeting PTEN, highlighting that miR‑141 may serve as a novel therapeutic target for liver fibrosis.

Natural Sulfur-Containing Compounds: An Alternative Therapeutic Strategy against Liver Fibrosis

Liver fibrosis is a pathophysiologic process involving the accumulation of extracellular matrix proteins as collagen deposition. Advanced liver fibrosis can evolve in cirrhosis, portal hypertension and often requires liver transplantation. At the cellular level, hepatic fibrosis involves the activation of hepatic stellate cells and their transdifferentiation into myofibroblasts. Numerous pro-fibrogenic mediators including the transforming growth factor-β1, the platelet-derived growth factor, endothelin-1, toll-like receptor 4, and reactive oxygen species are key players in this process. Knowledge of the cellular and molecular mechanisms underlying hepatic fibrosis development need to be extended to find novel therapeutic strategies. Antifibrotic therapies aim to inhibit the accumulation of fibrogenic cells and/or prevent the deposition of extracellular matrix proteins. Natural products from terrestrial and marine sources, including sulfur-containing compounds, exhibit promising activities for the treatment of fibrotic pathology. Although many therapeutic interventions are effective in experimental models of liver fibrosis, their efficacy and safety in humans are largely unknown. This review aims to provide a reference collection on experimentally tested natural anti-fibrotic compounds, with particular attention on sulfur-containing molecules. Their chemical structure, sources, mode of action, molecular targets, and pharmacological activity in the treatment of liver disease will be discussed.