miR-193a/b-3p relieves hepatic fibrosis and restrains proliferation and activation of hepatic stellate cells

MicroRNA-30a depresses hepatic stellate cell activation against liver fibrosis through blockade of the TGF-β1/Smad2/3 pathway

This study explored the mechanism of microRNA (miR)-30a in the activation of hepatic stellate cells (HSCs) to deepen the understanding of the pathogenesis of liver fibrosis. Subsequent to knockdown and ectopic experiments, HSCs were induced with 10 ng/mL transforming growth factor (TGF)-β1 to inspect the role of the miR-30a/TGF-β receptor 1 (TGFBR1) axis in HSC proliferation and activation. qRT-PCR was utilized to examine TGFBR1 mRNA and miR-30a expression and western blot to test TGFBR1, alpha smooth muscle actin (α-SMA), Collagen I and mothers against DPP homolog 2/3 (Smad2/3) protein expression. The fluorescence intensity of α-SMA was measured with immunofluorescence staining. The interaction of TGFBR1 with miR-30a was tested with a dual-luciferase reporter assay. TGF-β1 treated HSCs had upregulated expressions of α-SMA and Collagen I. In addition, downregulated miR-30a, upregulated TGFBR1 and activated TGF-β1/Smad2/3 pathway were found in activated HSCs. Upregulation of miR-30a or downregulation of TGFBR1 suppressed the activation and growth of HSCs. miR-30a repression activated the TGF-β1/Smad2/3 pathway and promoted HSC proliferation and activation, while suppression of TGFBR1 revered these effects. miR-30a was an upstream regulatory factor of TGFBR1. miR-30a blocks the TGF-β1/Smad2/3 pathway to inhibit HSC activation against liver fibrosis by targeting TGFBR1.

Dendritic cells originating exosomal miR-193b-3p induces regulatory T cells to alleviate liver transplant rejection

BACKGROUND

Exosomes exert considerable influence in mediating regulatory T (Treg) cells differentiation, which attach great importance to attenuating acute cellular rejection after liver transplantation (LT). And, miRNAs are known to play essential roles in cell-cell communication delivered by exosomes. However, the function of exosomal miRNAs in regulating Treg cells after LT remains unknown. Here, we performed an expression profiling analysis of exosome-miRNAs from human plasma after LT and investigated their immunoregulatory effects on Treg cells.

METHODS

Fifty-eight LT patients and nine donors were included in this report. miRNA profiles in plasma exosomes were analyzed using next-generation sequencing. Flow cytometry, HE and multiplex immunofluorescent staining were used to identify Treg cells in the liver and peripheral blood. A lentiviral vector system was used to overexpress miR-193b-3p in dendritic cells (DCs), and exosomes isolated from these transfected cells were co-cultured with spleen lymphocytesin vitro. A quantitative Real-time PCR and enzyme-linked immunosorbent assay were used to detect the expression of cytokines.

RESULTS

Treg cell infiltration was increased in the liver along with Th17 and CD8+ T cell, and it was down-regulated in peripheral blood in the acute rejection group. High-throughput sequencing revealed that miR-193b-3p was markedly up-regulated in plasma exosomes of non-rejection LT patients. The NLRP3 inflammasome was screened as a target for miR-193b-3p based on target prediction and functional enrichment analyses. Exosomal miR-193b-3p derived from DCs increased Treg cells as demonstrated in vitro. miR-193b-3p overexpression down-regulated NLRP3 as well as the inflammatory cytokines IL-1β and IL-17A while increasing levels of the cytokines IL-10 and TGF-β.

CONCLUSION

DC derived exosomal miR-193b-3p promoted Treg cells by inhibiting NLRP3 expression. These findings not only provide a new perspective on the mechanisms, but also hold great promise for the treatment or prevention of liver allograft rejection.

Mesenchymal stem cell-derived exosomes and non-coding RNAs: Regulatory and therapeutic role in liver diseases

Liver disease has become a major health problem worldwide due to its high morbidity and mortality. In recent years, a large body of literature has shown that mesenchymal stem cell-derived exosomes (MSC-Exo) are able to play similar physiological roles as mesenchymal stem cells (MSCs). More importantly, there is no immune rejection caused by transplanted cells and the risk of tumor formation, which has become a new strategy for the treatment of various liver diseases. Moreover, accumulating evidence suggests that non-coding RNAs (ncRNAs) are the main effectors by which they exert hepatoprotective effects. Therefore, by searching the databases of Web of Science, PubMed, ScienceDirect, Google Scholar and CNKI, this review comprehensively reviewed the therapeutic effects of MSC-Exo and ncRNAs in liver diseases, including liver injury, liver fibrosis, and hepatocellular carcinoma. According to the data, the therapeutic effects of MSC-Exo and ncRNAs on liver diseases are closely related to a variety of molecular mechanisms, including inhibition of inflammatory response, alleviation of liver oxidative stress, inhibition of apoptosis of hepatocytes and endothelial cells, promotion of angiogenesis, blocking the cell cycle of hepatocellular carcinoma, and inhibition of activation and proliferation of hepatic stellate cells. These important findings will provide a direction and basis for us to explore the potential of MSC-Exo and ncRNAs in the clinical treatment of liver diseases in the future.

MicroRNA Profiling in the Aqueous Humor of Keratoconus Eyes

Purpose

To identify differentially expressed (DE) microRNAs (miRNAs) in the aqueous humor (AH) of keratoconus (KC) eyes using next-generation sequencing and to explore whether DE miRNAs might play roles in KC pathophysiology.

Methods

The small RNAs in the AH of 15 KC eyes and 15 myopia eyes (the control group) were sequenced on an Illumina NovaSeq 6000 platform. Gene Oncology and Kyoto Encyclopedia of Genes and Genome enrichment analyses were performed. Receiver operating characteristic curves were used to identify potential KC biomarkers.

Results

We identified 204 miRNAs in the AH of the KC group and 200 in the AH of the control group. Fourteen miRNAs were differentially expressed between the two groups; four miRNAs were upregulated and 10 downregulated in KC AH. The possible pathways regulated by the DE miRNAs included antigen processing and presentation, endocytosis, mismatch repair, and Hippo signaling. The AH concentrations of miR-222-3p, miR-363-3p, and miR-423-5p exhibited areas under the curves of 1.

Conclusions

We profiled the DE miRNAs of the AH of KC eyes. These miRNAs may be associated with KC pathogenesis and could serve as KC biomarkers.

Translational Relevance

Data on aberrantly expressed miRNAs in KC combined with bioinformatics analyses suggest possible roles for specific miRNAs. The DE miRNAs may serve as diagnostic KC biomarkers.

Long Non-Coding RNA MIR31HG Promotes the Transforming Growth Factor β-Induced Epithelial-Mesenchymal Transition in Pancreatic Ductal Adenocarcinoma Cells

The epithelial-to-mesenchymal transition (EMT) describes a biological process in which polarized epithelial cells are converted into highly motile mesenchymal cells. It promotes cancer cell dissemination, allowing them to form distal metastases, and also involves drug resistance in metastatic cancers. Transforming growth factor β (TGFβ) is a multifunctional cytokine that plays essential roles in development and carcinogenesis. It is a major inducer of the EMT. The MIR31 host gene (MIR31HG) is a newly identified long non-coding (lnc)RNA that exhibits ambiguous roles in cancer. In this study, a cancer genomics analysis predicted that MIR31HG overexpression was positively correlated with poorer disease-free survival of pancreatic ductal adenocarcinoma (PDAC) patients, which was associated with upregulation of genes related to TGFβ signaling and the EMT. In vitro evidence demonstrated that TGFβ induced MIR31HG expression in PDAC cells, and knockdown of MIR31HG expression reversed TGFβ-induced EMT phenotypes and cancer cell migration. Therefore, MIR31HG has an oncogenic role in PDAC by promoting the EMT.

MicroRNA-193b impairs muscle growth in mouse models of type 2 diabetes by targeting the PDK1/Akt signalling pathway

AIMS/HYPOTHESIS

Type 2 diabetes is associated with a reduction in skeletal muscle mass; however, how the progression of sarcopenia is induced and regulated remains largely unknown. We aimed to find out whether a specific microRNA (miR) may contribute to skeletal muscle atrophy in type 2 diabetes.

METHODS

Adeno-associated virus (AAV)-mediated skeletal muscle miR-193b overexpression in C57BLKS/J mice, and skeletal muscle miR-193b deficiency in db/db mice were used to explore the function of miR-193b in muscle loss. In C57BL/6 J mice, tibialis anterior-specific deletion of 3-phosphoinositide-dependent protein kinase-1 (PDK1), mediated by in situ AAV injection, was used to confirm whether miR-193b regulates muscle growth through PDK1. Serum miR-193b levels were also analysed in healthy individuals (n = 20) and those with type 2 diabetes (n = 20), and correlations of miR-193b levels with HbA_1c, fasting blood glucose (FBG), body composition, triacylglycerols and C-peptide were assessed.

RESULTS

In this study, we found that serum miR-193b levels increased in individuals with type 2 diabetes and negatively correlated with muscle mass in these participants. Functional studies further showed that AAV-mediated overexpression of miR-193b induced muscle loss and dysfunction in healthy mice. In contrast, suppression of miR-193b attenuated muscle loss and dysfunction in db/db mice. Mechanistic analysis revealed that miR-193b could target Pdk1 expression to inactivate the Akt/mammalian target of rapamycin (mTOR)/p70S6 kinase (S6K) pathway, thereby inhibiting protein synthesis. Therefore, knockdown of PDK1 in healthy mice blocked miR-193b-induced inactivation of the Akt/mTOR/S6K pathway and impairment of muscle growth.

CONCLUSIONS/INTERPRETATION

Our results identified a previously unrecognised role of miR-193b in muscle function and mass that could be a potential therapeutic target for treating sarcopenia.

Over-expression of miR-193a-3p regulates the apoptosis of colorectal cancer cells by targeting PAK3

Although dysregulated expression of microRNAs (miRNA) has been investigated in colorectal cancer (CRC), MiR-193a-3p, as a tumor inhibitor, is less studied. To investigate the function and mechanism of miR-193a-3p in CRC, the potential function of miR-193a-3p in regulating PAK3 in CRC with a series of experimental assays including western blotting, qRT-PCR, bioinformatics analysis, a luciferase reporter assay, flow cytometry, Transwell assay, CCK8 assay and immunofluorescence were performed in this study. The results showed that miR-193a-3p was down-regulated in CRC tissues and cell lines, which was also correlated with tumor progression. PAK3 was predicted as a target gene of miR-193a-3p in CRC cells by TargetScan database, which was confirmed by luciferase assays. Moreover, overexpression of miR-193a-3p suppressed the viability, cell cycle progression, migration, and invasion, and induced apoptosis of CRC cells in vitro by regulating the PAK3 signaling pathway. Therefore, miR-193a-3p may serve as a tumor suppressor and potential target for CRC treatment.

Mig-6 Inhibits Autophagy in HCC Cell Lines by Modulating miR-193a-3p

Mitogen-inducible gene 6 (Mig-6) is a tumor suppressor gene that plays an important role in many types of cancers by interacting with EGFR. However, its molecular mechanism in hepatocellular carcinoma (HCC) and its relationship with miRNAs need to be elucidated. Therefore, this study aimed to explore whether Mig-6 could promote apoptosis and the inhibition of autophagy via its downstream miRNA in HCC cell lines. We used two cell lines, HepG2 and HLE, to establish Mig-6 overexpression and knockdown experiments, as well as miR-193a mimic and inhibitor experiments. The miRNA microarray profiling was also used to verify Mig-6-regulated miRNA. We found that Mig-6 induced apoptosis and reduced autophagy of HCC cell lines. miR-193a-3p is a Mig-6-regulated miRNA in the Mig-6-overexpression model. It affected the apoptosis and autophagy of HCC cells, at least partly by regulating the expression of TGF-β2. Additionally, the relationship between Mig-6 and transforming growth factor TGF-β2 was explored in depth for the first time. These findings revealed an important role of Mig-6 in the apoptosis and autophagy of HCC cells by regulating miR-193a-3p, providing a novel insight into the therapeutic target in HCC.

MicroRNA-494-3p prevents liver fibrosis and attenuates hepatic stellate cell activation by inhibiting proliferation and inducing apoptosis through targeting TRAF3

INTRODUCTION AND OBJECTIVES

Alcoholic hepatitis (AH) is characterized by high morbidity and mortality. MicroRNA-494-3p is possibly involved in the regulation of cancers, but its role in AH has been rarely studied.

MATERIALS AND METHODS

AH mice model and primarily cultured mice hepatic stellate cells (HSCs) model were constructed. Levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were analyzed by ELISA. Expressions of miRNAs, HSC activation-related proteins and fibrosis-related protein were analyzed by qRT-PCR and Western blot. Cell counting kit, colony formation and flow cytometry assays were used to detect cell viability, proliferation and apoptosis, respectively. The relationship between TNF receptor-associated factor 3 (TRAF3) and miR-494-3p was predicted and verified by TargetScan and dual-luciferase assay, respectively. Results of the above experiments were verified by rescue experiments using TRAF3.

RESULTS

Liver damage and miRNA expression were observed in AH mice, and AST and ALT levels were increased in serum of AH mice. MiR-494-3p was reduced in AH liver tissues, and it decreased the levels of α-SMA and fibrosis-related proteins. HSCs were isolated, and activating HSCs or upregulating miR-494-3p had a regulatory effect on the levels of miR-494-3p, HSC activation-related proteins and fibrosis-related proteins as well as cell viability, proliferation and apoptosis. In addition, miR-494-3p targeted TRAF3 and inhibited TRAF3 expression, while overexpressed TRAF3 promoted TRAF3 expression and rescued the regulatory effect of miR-494-3p on the levels of related proteins as well as cell viability, proliferation and apoptosis.

CONCLUSIONS

This study provided a novel mechanistic comprehension of the anti-fibrotic effect of miR-494-3p.

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.

MicroRNAs in Transforming Growth Factor-Beta Signaling Pathway Associated With Fibrosis Involving Different Systems of the Human Body

Fibrosis, a major cause of morbidity and mortality, is a histopathological manifestation of many chronic inflammatory diseases affecting different systems of the human body. Two types of transforming growth factor beta (TGF-β) signaling pathways regulate fibrosis: the canonical TGF-β signaling pathway, represented by SMAD-2 and SMAD-3, and the noncanonical pathway, which functions without SMAD-2/3 participation and currently includes TGF-β/mitogen-activated protein kinases, TGF-β/SMAD-1/5, TGF-β/phosphatidylinositol-3-kinase/Akt, TGF-β/Janus kinase/signal transducer and activator of transcription protein-3, and TGF-β/rho-associated coiled-coil containing kinase signaling pathways. MicroRNA (miRNA), a type of non-coding single-stranded small RNA, comprises approximately 22 nucleotides encoded by endogenous genes, which can regulate physiological and pathological processes in fibrotic diseases, particularly affecting organs such as the liver, the kidney, the lungs, and the heart. The aim of this review is to introduce the characteristics of the canonical and non-canonical TGF-β signaling pathways and to classify miRNAs with regulatory effects on these two pathways based on the influenced organ. Further, we aim to summarize the limitations of the current research of the mechanisms of fibrosis, provide insights into possible future research directions, and propose therapeutic options for fibrosis.

Integrated Analysis of Hepatic miRNA and mRNA Expression Profiles in the Spontaneous Reversal Process of Liver Fibrosis

Liver fibrosis results from the imbalance between extracellular matrix (ECM) production and degradation, which is a common pathological consequence of various chronic liver diseases. Although many miRNAs have been reported in liver fibrosis progression, miRNA-mRNA interactions in its reversal process remain to be elucidated. In the current study, we performed an integrated analysis of miRNA and mRNA expression profiles in the mouse model with the spontaneous reversal potency of liver fibrosis. A total of 102 miRNA and 2,845 mRNAs showed significant differential expression in reversal mice compared to fibrotic mice. Moreover, 3,769 putative negatively correlated miRNA-mRNA pairs were revealed to be potentially implicated in the biological function regulation of small molecule metabolism and ECM organization. By integrating miRNA-mRNA regulatory networks, mmu-miR-1843a-5p, mmu-miR-193a-5p, mmu-miR-194-2-3p, and mmu-miR-30c-2-3p were identified as lysyl oxidases-specific miRNAs that were correlated with fibrosis reversal. Our results provided potential candidate targets for the treatment of liver fibrosis.

Mitochondrial transplantation therapy inhibit carbon tetrachloride-induced liver injury through scavenging free radicals and protecting hepatocytes

Carbon tetrachloride (CCl4)-induced liver injury is predominantly caused by free radicals, in which mitochondrial function of hepatocytes is impaired, accompanying with the production of ROS and decreased ATP energy supply in animals intoxicated with CCl4. Here we explored a novel therapeutic approach, mitochondrial transplantation therapy, for treating the liver injury. The results showed that mitochondria entered hepatocytes through macropinocytosis pathway, and thereby cell viability was recovered in a concentration-dependent manner. Mitochondrial therapy could increase ATP supply and reduce free radical damage. In liver injury model of mice, mitochondrial therapy significantly improved liver function and prevented tissue fibrogenesis. Transcriptomic data revealed that mitochondrial unfold protein response (UPRmt), a protective transcriptional response of mitochondria-to-nuclear retrograde signaling, would be triggered after mitochondrial administration. Then the anti-oxidant genes were up-regulated to scavenge free radicals. The mitochondrial function was rehabilitated through the transcriptional activation of respiratory chain enzyme and mitophage-associated genes. The protective response re-balanced the cellular homeostasis, and eventually enhanced stress resistance that is linked to cell survival. The efficacy of mitochondrial transplantation therapy in the animals would suggest a novel approach for treating liver injury caused by toxins.

Inhibition of miR-188-5p alleviates hepatic fibrosis by significantly reducing the activation and proliferation of HSCs through PTEN/PI3K/AKT pathway

Persistent hepatic damage and chronic inflammation in liver activate the quiescent hepatic stellate cells (HSCs) and cause hepatic fibrosis (HF). Several microRNAs regulate the activation and proliferation of HSCs, thereby playing a critical role in HF progression. Previous studies have reported that miR‐188‐5p is dysregulated during the process of HF. However, the role of miR‐188‐5p in HF remains unclear. This study investigated the potential role of miR‐188‐5p in HSCs and HF. Firstly, we validated the miR‐188‐5p expression in primary cells isolated from liver of carbon tetrachloride (CCl₄)‐induced mice, TGF‐β1‐induced LX‐2 cells, livers from 6‐month high‐fat diet (HFD)‐induced rat and 4‐month HFD‐induced mice NASH models, and human non‐alcoholic fatty liver disease (NAFLD) patients. Furthermore, we used miR‐188‐5p inhibitors to investigate the therapeutic effects of miR‐188‐5p inhibition in the HFD + CCl₄ induced in vivo model and the potential role of miR‐188‐5p in the activation and proliferation of HSCs. This present study reported that miR‐188‐5p expression is significantly increased in the human NAFLD, HSCs isolated from liver of CCl₄ induced mice, and in vitro and in vivo models of HF. Mimicking the miR‐188‐5p resulted in the up‐regulation of HSC activation and proliferation by directly targeting the phosphatase and tensin homolog (PTEN). Moreover, inhibition of miR‐188‐5p reduced the activation and proliferation markers of HSCs through PTEN/AKT pathway. Additionally, in vivo inhibition of miR‐188‐5p suppressed the HF parameters, pro‐fibrotic and pro‐inflammatory genes, and fibrosis. Collectively, our results uncover the pro‐fibrotic role of miR‐188‐5p. Furthermore, we demonstrated that miR‐188‐5p inhibition decreases the severity of HF by reducing the activation and proliferation of HSCs through PTEN/AKT pathway.

Circulatory microRNAs as potential biomarkers for fatty liver disease: the Rotterdam study

BACKGROUND

Fatty liver disease (FLD) is the most common cause of liver dysfunction in developed countries. There is great interest in developing clinically valid and minimally invasive biomarkers to enhance early diagnosis of FLD.

AIM

To investigate the potential of circulatory microRNAs (miRNAs) as biomarkers of FLD at the population level.

METHODS

Plasma levels of 2083 miRNAs were measured by RNA sequencing in 1999 participants from the prospective population-based Rotterdam Study cohort. The Hounsfield Unit (HU) attenuation of liver was measured using non-enhanced computed tomography (CT) scan. Logistic and linear regression models adjusting for potential confounders were used to examine the association of circulatory miRNAs with liver enzymes (n = 1991) and CT-based FLD (n = 954). Moreover, the association of miRNAs with hepatic steatosis and liver fibrosis was assessed longitudinally in individuals who underwent abdominal ultrasound (n = 1211) and transient elastography (n = 777) after a median follow-up of >6 years.

RESULTS

Cross-sectional analysis showed 61 miRNAs significantly associated with serum gamma-glutamyl transferase and/or alkaline phosphatase levels (Bonferroni-corrected P < 8.46 × 10^-5 ). Moreover, 17 miRNAs were significantly associated with CT-based FLD (P < 8.46 × 10^-5 ); 14 were among miRNAs associated with liver enzymes. Longitudinal analysis showed that 4 of these 14 miRNAs (miR-193a-5p, miR-122-5p, miR-378d and miR-187-3p) were significantly associated with hepatic steatosis (P < 3.57 × 10^-3 ) and three (miR-193a-5p, miR-122-5p and miR-193b-3p) were nominally associated with liver fibrosis (P < 0.05). Nine of the 14 identified miRNAs were involved in pathways underlying liver diseases.

CONCLUSIONS

Plasma levels of several miRNAs can be used as biomarkers of FLD, laying the groundwork for future clinical applications.

Depletion of serotonin relieves concanavalin A-induced liver fibrosis in mice by inhibiting inflammation, oxidative stress, and TGF-β1/Smads signaling pathway

Serotonin exerts important functions in several liver pathophysiological processes. In this study, we investigated the role of serotonin in concanavalin A (Con A)-induced liver fibrosis (LF) in mice and the underlying mechanisms. To establish the mouse model of LF, mice of wild-type (WT) and tryptophan hydroxylase 1 (Tph1) knockout (serotonin depletion) received Con A for 8 successive weeks. Degree of fibrosis was assessed by Sirius red staining, as well as the measurements of alpha smooth muscle actin (α- SMA), hydroxyproline (Hyp) and type I collagen in liver tissues. To elucidate the potential mechanisms, we assessed the effect of serotonin depletion on inflammatory, oxidative stress as well as TGF-β1/Smads signaling pathway. We found that serotonin depletion significantly inhibited collagen deposition as evaluated by less collagenous fiber in Sirus Red staining and reduced contents of Hyp and type I collagen. In addition, the absence of serotonin significantly inhibited the release of several inflammatory cytokines, including interleukin-6 (IL-6), interferon-gamma (IFN-γ), tumor necrosis-alpha (TNF-α), and transforming growth factor β1 (TGF-β1). Oxidative stress was also largely mitigated in LF mice with serotonin deficiency as manifested by the decreases of oxidative stress markers (malonaldehyde (MDA) and myeloperoxidase (MPO)), as well as the increases of antioxidant stress indicators (glutathione (GSH), and GSH-px, catalase (CAT), superoxide dismutase (SOD)) in liver tissues. Moreover, the lack of serotonin may provide an antifibrotic role by inhibiting the intrahepatic expressions of TGF-β1, phosphorylated-smad2 (p-smad2), and phosphorylated-smad3 (p-smad3). These results indicated that, serotonin depletion attenuates Con A-induced LF through the regulation of inflammatory response, oxidative stress injury, and TGF-β1/Smads signaling pathway.

MiR-34c promotes hepatic stellate cell activation and Liver Fibrogenesis by suppressing ACSL1 expression

Normally, there are multiple microRNAs involved in the pathogenesis of liver fibrosis. In our work, we aimed at identifying the role of miR-34c in the hepatic stellate cell (HSC) activation and liver fibrosis and its potential mechanism. Our results have shown that during natural activation of HSC, the level of miR-34c was increased significantly whereas acyl-CoA synthetase long-chain family member-1(ACSL1), which is a key enzyme can affect fatty acid(FA) synthesis, was decreased. A double fluorescence reporter assay further confirmed that ACSL1 is a direct target gene of miR-34c. Moreover, the inhibition of miR-34C can attenuate the synthesis of collagen in HSC-T6. In our rescue assay, ACSL1 expression was 1.49-fold higher compared to normal control cells which were transfected with the miR-34c inhibitor in a stable low expression ACSL1 cell line. While at the same time, α-SMA and Col1α expression decreased by 18.22% and 2.58%, respectively. Moreover, we performed an in vivo model using dimethylnitrosamine (DMN) in conjunction with the miR-34c agomir, combined with the treatment of DMN and the miR-34c agomir can increase liver fibrosis. Meanwhile, the degree of hepatic fibrosis was increased and lipid droplets reduced dramatically in rats and HSC-T6 cell treated with miR-34c mimics alone compared to untreated groups. Our results indicate that miR-34c plays an essential role in liver fibrosis by targeting ACSL1 closely associated with lipid droplets, and it might be used as a potential therapeutic target.

Circular RNAs associated with a mouse model of concanavalin A-induced autoimmune hepatitis: preliminary screening and comprehensive functional analysis

Without treatment, autoimmune hepatitis (AIH) often leads to cirrhosis, liver failure and, in some cases, death. However, the pathogenesis of AIH remains incompletely understood. Here, we explored the relationship between differentially expressed circular RNAs (DECs) and development of AIH by obtaining an expression profile of DECs in a concanavalin A‐induced AIH mouse model by microarray. In total, we identified 27 DECs; the host genes of these DECs were annotated with 140 Gene Ontology terms and 19 pathways, revealing potential roles in the metabolism of cellular ions and regulation of protein expression, as well as possible involvement in endocytosis and apoptosis. We constructed a circular RNA–microRNA network that was used to infer that a mmu_circ_0001520/mmu‐miR‐193b‐3p/MAPK10 network may be associated with the occurrence of AIH. These findings may help lay the foundation for validation of the potential roles of circular RNAs in AIH.

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

Background

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

Methods

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

Results

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

Conclusion

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

MicroRNA interplay between hepatic stellate cell quiescence and activation

Hepatic stellate cells (HSCs) activation play a significant role in the progression of hepatic fibrosis. During chronic liver diseases, hepatocytes are damaged severely and secrete several pro-inflammatory markers and profibrogenic cytokines via modulation of a variety of signaling pathways that are responsible for the activation of HSCs. The microRNAs (miRNA or miR) have the potential to modulate fibrogenic signaling pathways in HSCs. A variety of miRNAs are identified as profibrogenic and are capable of activating HSCs by modulating fibrosis-associated signaling pathways such as transforming growth factor-β/Smad, Wnt/β-catenin, Hedgehog, Snail and Notch in the injured liver. On the other hand, HSCs also have certain antifibrotic miRNAs and these include miR-16, miR-19b, miR-29, miR-30, miR-101, miR-122, miR-133a, miR-144, miR-146a, miR-150-5p, miR-155, miR-195, miR-200a, miR-214, miR-335, miR-370, miR-454, miR-483, etc. are responsible for maintenance of the quiescent phenotype of normal HSCs, apoptosis induction and phenotypic reversion of activated HSCs, inhibition of HSCs proliferation, suppression of the extracellular matrix-associated gene expressions, etc. Thus, understanding of HSCs specific miRNAs regulation may provide new ideas for the targeted therapy of hepatic fibrosis at molecular level in the near future. Therefore, this review focusses on the modulation of miRNAs profile during the HSCs activation in the fibrotic liver.

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.

Characterization and functional prediction of the microRNAs differentially expressed in a mouse model of concanavalin A-induced autoimmune hepatitis

In order to investigate the altered expression of microRNAs (miRNAs) in the development of autoimmune hepatitis (AIH), the aberrantly expressed miRNAs in the concanavalin A (Con A)-induced AIH mouse model were identified for the first time with microarray in this study. A total of 49 miRNAs (31 up- and 18 down-regulated) were screened out, and the qRT-PCR validation results of 12 chosen miRNAs were consistent with the microarray data. Combined with the profiling of differently expressed mRNAs in the same model (data not shown), 959 predicted target genes (601 for up- and 358 for down-regulated miRNAs) were obtained according to the intersection of databases miRWalk and miRDB, and several hub genes were obtained from the regulatory networks, including Cadm1 and Mier3. These target genes were significantly enriched in the Gene ontology (GO) terms of "transcription, DNA-templated", and were annotated in 47 signaling pathways, comprising "Wnt signaling pathway", "Hippo signaling pathway", "Ferroptosis" and "mitogen-activated protein kinase (MAPK) signaling pathway", according to the GO and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. In the miRNA-GO-network, mmu-miR-193b-3p were exhibited in 33 GO terms of biological processes (BP), and the most significantly regulated GO term in BP categories was "regulation of transcription, DNA-templated". While in the miRNA-pathway-network, mmu-miR-7005-5p were enriched in 37 pathways, which was more than the other specifically expressed miRNAs, and the most significantly enriched pathways were "Endocytosis" and "MAPK signaling pathway". In conclusion, these differently expressed miRNAs seemed to be associated with the onset of AIH, and have the potential to serve as the new targets on the treatment of this disease.

Inhibition of microRNA-150-5p alleviates cardiac inflammation and fibrosis via targeting Smad7 in high glucose-treated cardiac fibroblasts

Hyperglycemia-induced cardiac fibrosis is a prominent characteristic of diabetic cardiomyopathy. Changes in proinflammatory cytokines have been shown to lead to cardiac fibrosis in patients with diabetes mellitus. This study aimed to investigate the role of miR-150-5p in mediating cardiac inflammation and fibrosis in cardiac fibroblasts (CFs). Herein, we found that high-glucose (HG) treatment significantly induced cardiac inflammation, as manifested by increased proinflammatory cytokine production (IL-1β) and NF-κB activity in CFs. Moreover, HG markedly aggravated cardiac fibrosis and increased levels of fibrotic markers (CTGF, FN, α-SMA) and extracellular matrix proteins (Col-I, Col-III) in CFs. At the same time, HG disturbed the TGF-β1/Smad signaling pathway, as evidenced by increases in TGF-β1 and p-Smad2/3 levels and decreases in Smad7 levels in CFs. Furthermore, we found that miR-150-5p was upregulated by HG, which negatively regulated Smad7 expression at the posttranscription level. Further study demonstrated that cardiac inflammation and fibrosis in CFs were corrected following miR-150-5p knockdown, but exacerbated by miR-150-5p overexpression. These data indicated that miR-150-5p inhibition could ameliorate NF-κB-related inflammation and TGF-β1/Smad-induced cardiac fibrosis through targeting Smad7. Thus, miR-150-5p may be a novel promising target for treating diabetic cardiomyopathy.

Crosstalk network among multiple inflammatory mediators in liver fibrosis

Liver fibrosis is the common pathological basis of all chronic liver diseases, and is the necessary stage for the progression of chronic liver disease to cirrhosis. As one of pathogenic factors, inflammation plays a predominant role in liver fibrosis via communication and interaction between inflammatory cells, cytokines, and the related signaling pathways. Damaged hepatocytes induce an increase in pro-inflammatory factors, thereby inducing the development of inflammation. In addition, it has been reported that inflammatory response related signaling pathway is the main signal transduction pathway for the development of liver fibrosis. The crosstalk regulatory network leads to hepatic stellate cell activation and proinflammatory cytokine production, which in turn initiate the fibrotic response. Compared with the past, the research on the pathogenesis of liver fibrosis has been greatly developed. However, the liver fibrosis mechanism is complex and many pathways involved need to be further studied. This review mainly focuses on the crosstalk regulatory network among inflammatory cells, cytokines, and the related signaling pathways in the pathogenesis of chronic inflammatory liver diseases. Moreover, we also summarize the recent studies on the mechanisms underlying liver fibrosis and clinical efforts on the targeted therapies against the fibrotic response.

miR-193a/b-3p relieves hepatic fibrosis and restrains proliferation and activation of hepatic stellate cells

MicroRNAs (miRNAs) have been confirmed to participate in liver fibrosis progression and activation of hepatic stellate cells (HSCs). In this study, the role of miR‐193a/b‐3p in concanavalin A (ConA)‐induced liver fibrosis in mice was evaluated. According to the results, the expression of miR‐193a/b‐3p was down‐regulated in liver tissues after exposure to ConA. Lentivirus‐mediated overexpression of miR‐193a/b‐3p reduced ConA‐induced liver injury as demonstrated by decreasing ALT and AST levels. Moreover, ConA‐induced liver fibrosis was restrained by the up‐regulation of miR‐193a/b‐3 through inhibiting collagen deposition, decreasing desmin and proliferating cell nuclear antigen (PCNA) expression and lessening the content of hydroxyproline, transforming growth factor‐β1 (TGF‐β1) and activin A in liver tissues. Furthermore, miR‐193a/b‐3p mimics suppressed the proliferation of human HSCs LX‐2 via inducing the apoptosis of LX‐2 cells and lowering the levels of cell cycle‐related proteins Cyclin D1, Cyclin E1, p‐Rb and CAPRIN1. Finally, TGF‐β1 and activin A‐mediated activation of LX‐2 cells was reversed by miR‐193a/b‐3p mimics via repressing COL1A1 and α‐SMA expression, and restraining the activation of TGF‐β/Smad2/3 signalling pathway. CAPRIN1 and TGF‐β2 were demonstrated to be the direct target genes of miR‐193a/b‐3p. We conclude that miR‐193a/b‐3p overexpression attenuates liver fibrosis through suppressing the proliferation and activation of HSCs. Our data suggest that miR‐193a‐3p and miR‐193b‐3p may be new therapeutic targets for liver fibrosis.