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

Molecular Biological Mechanisms of Action of Chrysophanol in Hepatic Stellate Cells Activated by Hepatic B Virus X Based on Network Pharmacology

INTRODUCTION

Chrysophanol (Cho) is a natural anthraquinone with biological effects such as inducing ferroptosis and anticancer activity. The hepatitis B virus X protein (HBx) is essential for HBV replication. We aimed to identify the key pathways in HBx-induced hepatic stellate cell (HSC) activation and to characterize the potential mechanisms of action of Cho against liver fibrosis.

METHODS

HSC-T6 cells were transfected with FLAG (control group) or FLAG-HBx (HBx group), and RNA sequencing and Western blotting analysis were conducted to assess the effects of HBx and Cho on specific molecular targets and signaling pathways.

RESULTS

Gene ontology and pathway analyses indicated that the genes targeted by HBx participate in immunological responses, chemokine and cytokine activity, cell-substrate adhesion, extracellular matrix organization, growth factor binding, defense responses, and antigen processing and presentation. RNA-seq and Western blotting data revealed that HBx-activated HSC-T6 cells exhibited upregulated expression of mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR), S6, phosphorylated S6 (p-S6), peroxisome proliferator-activated receptor (PPAR-α), phosphorylated-PPAR-α (p-PPAR-α), CYP27, α-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF), and Integrin-β1, which was reversed after treatment with Cho. These results were also verified in a HBx-activated HSC-T6 and LX-2 cell model and thioacetamide-induced liver fibrosis mouse model.

CONCLUSIONS

Thus, our findings indicate that Cho ameliorates HBx-induced HSC activation and liver fibrosis via inhibition of the mTOR and PPARs signaling pathways, suggesting that Cho is a potential therapeutic for chronic liver inflammation-mediated diseases.

Elevated mir-141 in obesity: Insights into the interplay with sirtuin 1 and non-alcoholic fatty liver disease

Background

Changes in gene expression related to obesity are linked to microRNAs, such as miR-141, which play a crucial role in metabolic homeostasis. Sirtuin 1 (SIRT1), an enzyme that plays a crucial role in regulating various cellular functions and metabolism, is implicated in obesity and the ensuing non-alcoholic fatty liver disease (NAFLD). The aim of this research was to evaluate the levels of miR-141 and its relationship with SIRT1 and NAFLD.

Methods

A group of 100 adults (50 with obesity and 50 with normal-weight) were selected and underwent complete clinical evaluation and anthropometric measurements. Biochemical parameters were assessed in blood serum, and the levels of miR-141 in plasma were measured by real-time PCR. The expression of the SIRT1 gene was also evaluated in the peripheral blood mononuclear cells using Real-time PCR. The ELISA technique was used to determine insulin levels. Liver steatosis was assessed by ultrasound.

Results

The results showed that levels of miR-141 were significantly increased in participants with obesity compared with the control group. Conversely, the expression of the SIRT1 gene in individuals with obesity was lower than that in control participants. A strong negative correlation was observed between miR-141 and SIRT1 and a strong positive association was observed between miR-141 and metabolic parameters. Furthermore, participants with fatty liver had significantly elevated levels of miR-141 gene expression and lower expression of SIRT1 gene, compared to those without fatty liver.

Conclusion

elevated levels of miR-141 in individuals with obesity might be a contributing factor in the repression of SIRT1 in obesity and its consequences, including NAFLD. Therefore, miR-141 might serve as a suitable diagnostic and therapeutic target in obesity and NAFLD.

Mesenchymal stem cell-originated exosomal circDIDO1 suppresses hepatic stellate cell activation by miR-141-3p/PTEN/AKT pathway in human liver fibrosis

Liver fibrosis is a common pathologic stage of the development of liver failure. It has showed that exosomes loaded with therapeutic circRNAs can be manufactured in bulk by exosome secreted cells in vitro, thus enabling personalized treatment. This study aimed to investigate the role of exosome-based delivery of circDIDO1 in liver fibrosis. Levels of genes and proteins were examined by qRT-PCR and Western blot. Cell proliferation, apoptosis, and cell cycle were analyzed by using cell counting kit-8 (CCK-8) assay, EdU assay, and flow cytometry, respectively. The binding between circDIDO1 and miR-141-3p was confirmed by dual-luciferase reporter, RNA pull-down and RIP assays. Exosomes were isolated by ultracentrifugation, and qualified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and Western blot. CircDIDO1 overexpression or miR-141-3p inhibition suppressed the proliferation, reduced pro-fibrotic markers, and induced apoptosis as well as cell cycle arrest in hepatic stellate cells (HSCs) by blocking PTEN/AKT pathway. Mechanistically, circDIDO1 acted as an endogenous sponge for miR-141-3p, further rescue experiments showed that circDIDO1 suppressed HSC activation by targeting miR-141-3p. Extracellular circDIDO1 could be incorporated into exosomes isolated from mesenchymal stem cells (MSCs), and transmitted to HSCs to restrain HSC activation. Clinically, low levels of serum circDIDO1 in exosome were correlated with liver failure, and serum exosomal circDIDO1 had a well diagnostic value for liver fibrosis in liver failure patients. Transfer of circDIDO1 mediated by MSC-isolated exosomes suppressed HSC activation through the miR-141-3p/PTEN/AKT pathway, gaining a new insight into the prevention of liver fibrosis in liver failure patients.

Noncoding RNAs Interactions in Hepatic Stellate Cells during Hepatic Fibrosis

Hepatic fibrosis is a reversible wound healing process following liver injury. Although this process is necessary for maintaining liver integrity, severe excessive extracellular matrix accumulation (ECM) could lead to permanent scar formation and destroy the liver structure. The activation of hepatic stellate cells (HSCs) is a key event in hepatic fibrosis. Previous studies show that most antifibrotic therapies focus on the apoptosis of HSCs and the prevention of HSC activation. Noncoding RNAs (ncRNAs) play a substantial role in HSC activation and are likely to be biomarkers or therapeutic targets for the treatment of hepatic fibrosis. This review summarizes and discusses the previously reported ncRNAs, including the microRNAs, long noncoding RNAs, and circular RNAs, highlighting their regulatory roles and interactions in the signaling pathways that regulate HSC activation in hepatic fibrosis.

Phosphatase and Tensin Homolog in Non-neoplastic Digestive Disease: More Than Just Tumor Suppressor

The Phosphatase and tensin homolog (PTEN) gene is one of the most important tumor suppressor genes, which acts through its unique protein phosphatase and lipid phosphatase activity. PTEN protein is widely distributed and exhibits complex biological functions and regulatory modes. It is involved in the regulation of cell morphology, proliferation, differentiation, adhesion, and migration through a variety of signaling pathways. The role of PTEN in malignant tumors of the digestive system is well documented. Recent studies have indicated that PTEN may be closely related to many other benign processes in digestive organs. Emerging evidence suggests that PTEN is a potential therapeutic target in the context of several non-neoplastic diseases of the digestive tract. The recent discovery of PTEN isoforms is expected to help unravel more biological effects of PTEN in non-neoplastic digestive diseases.

Xanthohumol Inhibits TGF-β1-Induced Cardiac Fibroblasts Activation via Mediating PTEN/Akt/mTOR Signaling Pathway

Background

Xanthohumol (Xn) is the most abundant prenylated flavonoid in Hops (Humulus lupulus L.), and exhibits a range of pharmacological activities. This study aimed to investigate the effect of Xn on TGF-β1-induced cardiac fibroblasts activation and elucidate the underlying mechanism.

Materials and Methods

The cellTiter 96^® AQueous one solution cell proliferation assay kit was adopted to determine the cell viability of cardiac fibroblasts, and the proliferation was detected through 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay. The α-SMA protein expression was measured by using immunofluorescence and Western blotting. Western blotting was conducted to test the protein expressions of collagen I and III, PTEN, p-Akt, Akt, p-mTOR, mTOR, p-Smad3, Smad3 and GAPDH. The mRNA levels of α-SMA, collagen I and III were determined by quantitative real-time polymerase chain reaction (PCR).

Results

Xn inhibited the TGF-β1-induced proliferation, differentiation and collagen overproduction of cardiac fibroblasts. TGF-β1 induced the down-regulated PTEN expression, Akt and mTOR phosphorylation. These effects of TGF-β1 were suppressed by Xn, while blocking of PTEN reduced Xn-mediated inhibitory effect on cardiac fibroblasts activation induced by TGF-β1.

Conclusion

Xn inhibits TGF-β1-induced cardiac fibroblasts activation via mediating PTEN/Akt/mTOR signaling pathway.

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.