Role of microRNA-122 in hepatic lipid metabolism of the weanling female rat offspring exposed to prenatal and postnatal caloric restriction

We examined the role of hepatocyte micro-RNA-122 and hypothalamic neuropeptides, in weanling (21d) female rats exposed to calorie restriction induced growth restriction either prenatally (IUGR), postnatally (PNGR) or both (IPGR) vs. ad lib fed controls (CON). IUGR were hyperinsulinemic, hyperleptinemic and dyslipidemic with high circulating miR-122. In contrast, PNGR and IPGR displayed insufficient glucose, insulin and leptin amidst high ketones with a dichotomy in circulating miR-122 of PNGR Collapse

Key Words

• Circadian rhythm
• Energy balance
• Fatty acid oxidation
• Hepatic fatty acid synthesis
• Hypothalamic genes
• Intra-uterine growth restriction
• microRNA-122

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MESH Headings

• Animals
• Body Weight
• Caloric Restriction/adverse effects
• Circadian Rhythm
• Energy Metabolism
• Fatty Acids/genetics
• Fatty Acids/metabolism
• Female
• Fetal Growth Retardation/etiology
• Gene Expression
• Growth Disorders/etiology
• Hypothalamus/chemistry
• Lipid Metabolism/genetics
• Lipid Metabolism/physiology
• Liver/chemistry
• Liver/metabolism
• MicroRNAs/genetics
• MicroRNAs/physiology
• Organ Size
• Pregnancy
• RNA, Messenger/analysis
• Rats
• Rats, Sprague-Dawley
• Weaning

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Grants

• R01 HD041230 NICHD NIH HHS
• R01 HD081206 NICHD NIH HHS

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Exosomal microRNA-122 mediates obesity-related cardiomyopathy through suppressing mitochondrial ADP-ribosylation factor-like 2

Emerging studies have demonstrated that microRNAs (miRs) participate in the development of multiple metabolic complications including cardiovascular diseases. Among them, circulating level of liver-secreted miR-122 was closely correlated with several consequence of heart diseases in clinical studies, and overexpression of miR-122 impaired cardiomyocyte function. However, it was unknown whether miR-122 could regulate cardiac biology in obesity. Therefore, present study was to disclose the role of miR-122 in cardiac metabolic disorders and potential molecular mechanisms. Through utilizing clinical samples and high fat diet-fed mice, we investigated the physiological roles of miR-122 in obesity-related cardiomyopathy. Besides, present study explored the mitochondrial function under exosomal miR-122 stimulation in mouse primary cardiomyocytes. In clinical samples and obese mice, the circulating level of exosomal miR-122 was positively correlated with cardiac dysfunctional parameters, including reduction in ejection fraction (EF) and increased levels of NT-proBNP. Human plasma exosomes transported miR-122 into mouse primary cardiomyocytes, and impaired mitochondrial ATP production and oxygen consumption, whereas miR-122 sponge improved these inhibitory effects. In dietary-induced mice, increased hepatic and circulating exosomal miR-122 deteriorated cardiac structure and functional index, and inhibited mitochondrial function. Liver-specific blockage of miR-122 attenuated abnormal cardiac remodeling. Mechanistically, miR-122 directly bound and suppressed mitochondrial protein ADP-ribosylation factor-like 2 (Arl-2) in vitro and in vivo Knockdown of Arl-2 abolished the mitochondrial benefits of miR-122 sponge in exosome-treated mouse primary cardiomyocytes.In conclusions, our present study firstly showed that liver-secreted exosomal miR-122 played a critical role in the development of metabolic cardiomyopathy, and miR-122/mitochondrial Arl-2 signaling affected cardiac energy homeostasis.

MicroRNA-122 in patients with hepatitis B and hepatitis B virus-associated hepatocellular carcinoma

Hepatitis B virus (HBV) infection is known as a serious problem in the domain of public health and approximately 350 million people across the world are affected with this infectious disease. As well, microRNAs are recognized as a type of small non-coding RNAs that can be widely used as a diagnostic biomarker and prognosis method of special diseases. In this respect, microRNA-122 or miR-122 can play a significant role in the pathogenesis of several hepatic diseases. Given the importance of microRNA-122 in the liver as well as its pathology, this study focused on the potential functions of microRNA-122 in pathogenesis, diagnosis, and treatment of HBV infection. In this regard, the findings of previous studies had indicated that expression of microRNA-122 in patients with HBV infection could be significantly deregulated. The results of this study were consistent with the idea that diagnosis and treatment of this infectious disease using microRNA-122 could be an efficient method.

Chemoresistance in gastric cancer is attributed to the overexpression of excision repair cross-complementing 1 (ERCC1) caused by microRNA-122 dysregulation

MicroRNAs are deemed as key regulators of gene expression. In particular, the elevated expression of excision repair cross-complementing 1 (ERCC1) significantly reduced the effectiveness of gastric cancer treatment by cisplatin (CDDP)-based therapies. In this paper, qRT-PCR and western blot were adopted to measure miR-122 and ERCC1 messenger RNA (mRNA) expression in all samples. Luciferase assay was carried out to verify the role of ERCC1 as a target of miR-122. The CCK-8 assay was carried out to study the effect of ERCC1 and miR-122 on cell survival and apoptosis. The results demonstrated that miR-122 expression was reduced in cisplatin-resistant gastric cancer. Using bioinformatic analysis, miR-122 was shown to target the 3'-UTR of human ERCC1. A dual-luciferase assay demonstrated that miR-122 downregulated ERCC1 expression, while the mutations in ERCC1 3'-UTR abolished its interaction with miR-122. Transfection of miR-122 mimics decreased the levels of ERCC1 mRNA and protein expression, while the transfection of miR-122 inhibitors increased the levels of both ERCC1 mRNA and protein expression. Furthermore, we found that overexpressed miR-122 promoted the proliferation of MKN74 cells and reduced their apoptotic by targeting ERCC1. In addition, the levels of miR-122 and ERCC1 were negatively correlated in gastric cancer samples. In summary, the reduced miR-122 expression may play an essential role in the induction of cisplatin-resistance by increasing ERCC1 expression.

Impact of sodium glucose cotransporter 2 inhibitor on histological features and glucose metabolism of non-alcoholic fatty liver disease complicated by diabetes mellitus

AIM

The aim of this study was to investigate the therapeutic potential of sodium glucose cotransporter 2 inhibitor (SGLT2I) as an effective therapeutic option for non-alcoholic fatty liver disease (NAFLD).

METHODS

In this prospective study, nine patients with NAFLD complicated by type 2 diabetes mellitus (DM), were introduced to the regimen of canagliflozin 100 mg once daily for 24 weeks and were evaluated by liver histology at pretreatment and at 24 weeks after the start of treatment. The primary outcome was histological improvement, defined as a decrease in NAFLD activity score of one point or more without worsening in fibrosis stage. Glucose metabolism was evaluated based on the meal tolerance test. The usefulness of extracellular and exosome microRNA-122 (miR-122) as early predictors of histological improvement was investigated.

RESULTS

All of the nine patients achieved histological improvement. Scores of steatosis, lobular inflammation, ballooning, and fibrosis stage decreased by 78%, 33%, 22%, and 33% at 24 weeks compared to the pretreatment, respectively. Six patients showed improvement in insulin resistance, and the other three patients showed partial improvement of insulin secretion function. Six patients, who showed a decrease in both extracellular and exosome miR-122 ratios (the ratio of miR-122 levels at 1 day after treatment to that at baseline), showed histological improvement. Furthermore, one patient, who showed a decrease in exosome miR-122 ratios regardless of the increase in extracellular miR-122 ratios, also showed decreases in NAFLD activity score and fibrosis stage.

CONCLUSION

A prospective study showed that SGLT2I for NAFLD complicated by DM improved histological features in connection with glucose metabolism. This trial was registered as clinical trial UMIN000018166.

Circulating miR-122 Is a Predictor for Virological Response in CHB Patients With High Viral Load Treated With Nucleos(t)ide Analogs

Chronic hepatitis B (CHB) infection remains worldwide health problem. Antiviral treatment options for CHB patients include nucleos(t)ide analogs (NAs) and interferon. Most of the current biomarkers for predicting treatment response are virus-dependent. MicroRNA-122 is the most abundant liver-specific miRNA and has been identified involved in multiple liver physiology and pathology including hepatotropic virus infection. To identify the role of miR-122 in NA therapy, 80 CHB patients with high viral load (HVL) were enrolled and serum miR-122 levels at baseline, week 12 and week 24 were measured. Serum miR-122 levels were significantly lower in patients who developed virological response (VR), compared with non-VR group. Levels of miR-122 at week 12 and week 24 were determined to be independent prognostic indicators for a VR with satisfactory AUROC values at 0.812 and 0.800, respectively. During NA therapy, serum miR-122 level deceased steadily and an earlier reduction was observed in VR group, indicating early reduction of miR-122 level might increase the possibility of developing virological response. In conclusion, we identified the dynamic change of serum miR-122 level and miR-122 levels at week 12 and week 24 as independent predictors for VR in CHB patients with HVL treated with NAs.

Clinical value of miRNA-122 in the diagnosis and prognosis of various types of cancer

The present study aimed to systematically analyze the value of microRNA-122 (miRNA-122) in the diagnosis and prognosis of hepatocellular carcinoma (HCC) and other types of cancer. First, the reverse transcription-quantitative polymerase chain reaction method was used to detect the expression levels of miRNA-122 in the serum samples of patients with HCC, benign lesions and healthy volunteers. Next, miRNA-seq data of miRNA-122 from The Cancer Genome Atlas database were used to analyze the differential expression and overall survival rate associated with a variety of types of cancer. Meanwhile, the target gene prediction of miRNA-122 was performed using four different software programs. Finally, 353 significant target genes were identified for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis. Finally, it was demonstrated that the expression levels of miRNA-122 in the HCC group were increased compared with the healthy group (P<0.001), but decreased with respect to the benign group (P<0.001). In addition, the combination of the miRNA-122 and a fetoprotein may further improve the diagnostic accuracy between the HCC and healthy groups (area under the curve, 0.980; 95% confidence interval, 0.958–1.000). It was also demonstrated that miRNA-122 exhibited significantly differential expression and the overall survival rate was predicted for various other types of cancer, including colorectal cancer, renal carcinoma, cholangiocarcinoma, prostate cancer and thyroid carcinoma. Functional enrichment analysis demonstrated that the target genes of miRNA-122 may contribute to the composition of the nucleus and cytoplasm, and regulate a variety of biological processes, including cardiac muscle cell differentiation and glucose metabolic processes via protein biosynthesis, estrogen and glucagon associated signaling pathways. These results revealed that miRNA-122 may be an indispensable biomarker for the diagnosis, prognostic evaluation and targeted therapy in pan-cancer.

Tanshinol relieves lipopolysaccharide-induced inflammatory injury of HaCaT cells via down-regulation of microRNA-122

This study investigated the effects of tanshinol (TAN) on lipopolysaccharide (LPS)-induced human keratinocytes inflammatory injury and underlying potential molecular mechanisms. Viability and apoptosis of HaCaT cells were assessed using MTT assay and Annexin V-FITC/PI staining, respectively. Quantitative reverse transcription-polymerase chain reaction was performed to measure the expression of microRNA-122 (miR-122) in HaCaT cells. Cell transfection was conducted to up-regulate the expression of miR-122. Western blotting was used to detect the protein expression levels of key factors involved in cell apoptosis, inflammatory response, c-Jun N-terminal kinase (JNK), and nuclear factor kappa B (NF-κB) pathways. We found that LPS treatment induced HaCaT cell inflammatory injury by inhibiting cell viability, promoting cell apoptosis, and enhancing the protein expression levels of cyclooxygenase 2 and inducible nitric oxide synthase. TAN treatment relieved LPS-induced HaCaT cell inflammatory injury. Moreover, TAN treatment attenuated LPS-induced activation of JNK and NF-κB pathways in HaCaT cells. Furthermore, TAN treatment alleviated LPS-induced up-regulation of miR-122. Overexpression of miR-122 reversed the effects of TAN on LPS-induced HaCaT cell inflammatory injury and activation of JNK and NF-κB pathways. In conclusion, TAN exerted anti-inflammatory and protective effects on keratinocytes injury. TAN relieved LPS-induced inflammatory injury of human HaCaT cells via down-regulating miR-122 and then inactivating JNK and NF-κB pathways.

MicroRNA-122 inhibits epithelial-mesenchymal transition of hepatic stellate cells induced by the TGF-β1/Smad signaling pathway

Transforming growth factor (TGF)-β1 may stimulate the activation of hepatic stellate cells (HSCs), resulting in the development of liver fibrosis. As micro RNA (miRNA)-122 is known to be associated with liver inflammation, its effects on the epithelial-mesenchymal transition (EMT) of HSCs through the inhibition of the TGF-β1/drosophila mothers against decapentaplegic protein 4 (Smad4) signaling pathway were investigated. The MTT assay was performed to explore the optimum TGF-β1 concentration suitable for HSC stimulation. Fluorescence microscopy was used to observe the transfection efficiency and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis were used to observe gene and protein expression levels of α-smooth muscle actin (α-SMA), E-cadherin, N-cadherin and Smad4, respectively, in HSCs treated with TGF-β1 or TGF-β1 and miRNA-122. MTT assay results indicated that the concentration of 10 µg/l TGF-β1 was suitable for maximum growth and survival of HSCs. Notably, the mRNA expression levels of N-cadherin and α-SMA were significantly increased (each, P<0.05), but the expression levels of E-cadherin were decreased following 10 µg/l TGF-β1 treatment. Similar results were observed regarding the protein expression levels of N-cadherin, α-SMA and E-cadherin. Furthermore, the expression of F-actin was increased in the 10 µg/l TGF-β1 treated group compared with the 0 µg/l TGF-β1 treaded group and stretching of the muscle fiber filament was observed. miRNA-122 lentiviral vector transfection significantly decreased the mRNA expression of N-cadherin and increased the mRNA expression of E-cadherin in HSCs stimulated with TGF-β1, as evident from RT-qPCR results. Similar results were also observed regarding the protein expression levels of N-cadherin and E-cadherin. The expression levels of Smad4, the primary component of the TGF-β1 signaling pathway, were significantly lower in cells treated with TGF-β1 and miRNA-122 (P<0.01) compared those treated with TGF-β1. Thus, miRNA-122 may inhibit the activation and EMT of HSCs stimulated by TGF-β1.

LncRNA HOTAIR epigenetically suppresses miR-122 expression in hepatocellular carcinoma via DNA methylation

Background

MicroRNA-122 (miR-122), a pivotal liver-specific miRNA, is frequently repressed in hepatocellular carcinoma (HCC) and associated with poor prognosis. Long non-coding RNA (lncRNA) HOTAIR has been proved to function as an oncogene in multiple cancers including HCC. However, the relationship between HOTAIR and miR-122 in HCC remains largely unknown.

Methods

We investigated the function of HOTAIR and miR-122 in HCC cell models and a xenograft mouse model. The regulatory network between HOTAIR and miR-122 was further detected following overexpression or knockdown of HOTAIR. DNA methylation status of miR-122 promoter region, as well as expression levels of DNMTs, EZH2 and Cyclin G1 were analyzed.

Findings

In this study, we found that HOTAIR was highly expressed whereas miR-122 was suppressed in HCC, and HOTAIR negatively regulated miR-122 expression in HCC cells. Furthermore, knockdown of HOTAIR dramatically inhibited HCC cell proliferation and induced cell cycle arrest in vitro and suppressed tumorigenicity in vivo by upregulating miR-122 expression. Mechanistically, a CpG island was located in the miR-122 promoter region. HOTAIR epigenetically suppressed miR-122 expression via DNMTs-mediated DNA methylation. Moreover, HOTAIR upregulated DNMTs expression via EZH2. In addition, suppression of miR-122 induced by HOTAIR directly reactivated oncogene Cyclin G1 expression. Collectively, our results suggest that HOTAIR epigenetically suppresses miR-122 expression via DNA methylation, leading to activation of Cyclin G1 and promotion of tumorigenicity in HCC, which provide new insight into the mechanism of HOTAIR-mediated hepatocarcinogenesis via suppressing miR-122.

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HOTAIR is highly expressed in HCC, and negatively regulates miR-122 expression in HCC cells.

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HOTAIR increased HCC cell proliferation and tumor growth through downregulating miR-122 expression.

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HOTAIR epigenetically suppressed miR-122 expression via DNMTs-mediated DNA methylation.

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HOTAIR upregulated DNMTs expression via EZH2.

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HOTAIR increased cyclin G1 expression through repressing miR-122.

Characterization of Triptolide-Induced Hepatotoxicity by Imaging and Transcriptomics in a Novel Zebrafish Model

Triptolide is a vine extract used in traditional Chinese medicines and associated with hepatotoxicity. In vitro data suggest that inhibition of RNA synthesis may be the mechanism of toxicity. For studying drug-induced liver injury the zebrafish has experimental, practical and financial advantages compared with rodents. The aim of this study was to explore the mechanism of triptolide toxicity using zebrafish as the model system. The effect of triptolide exposure on zebrafish larvae was determined with regard to mortality, histology, expression of liver specific microRNA-122 and liver volume. Fluorescent microscopy was used to track toxicity in the Tg(-2.8lfabp:GFP)^as3 zebrafish line. Informed by microscopy, RNA-sequencing was used to explore the mechanism of toxicity. Triptolide exposure resulted in dose-dependent mortality, a reduction in the number of copies of microRNA-122 per larva, hepatocyte vacuolation, disarray and oncotic necrosis, and a reduction in liver volume. These findings were consistent across replicate experiments. Time-lapse imaging indicated the onset of injury was 6 h after the start of exposure, at which point, RNA-sequencing revealed that 88% of genes were down-regulated. Immune response associated genes were up-regulated in the triptolide-treated larvae including nitric oxide synthase. Inhibition of nitric oxide synthase increased mortality. Triptolide induces hepatotoxicity in zebrafish larvae. This represents a new model of drug-induced liver injury that complements rodents. RNA sequencing, guided by time-lapse microscopy, revealed early down-regulation of genes consistent with previous invitro studies, and facilitated the discovery of mechanistic inflammatory pathways.

Mutational Analysis of the Bovine Hepacivirus Internal Ribosome Entry Site

In recent years, hepatitis C virus (HCV)-related viruses were identified in several species, including dogs, horses, bats, and rodents. In addition, a novel virus of the genus Hepacivirus has been discovered in bovine samples and was termed bovine hepacivirus (BovHepV). Prediction of the BovHepV internal ribosome entry site (IRES) structure revealed strong similarities to the HCV IRES structure comprising domains II, IIIabcde, pseudoknot IIIf, and IV with the initiation codon AUG. Unlike HCV, only one microRNA-122 (miR-122) binding site could be identified in the BovHepV 5' nontranslated region. In this study, we analyzed the necessity of BovHepV IRES domains to initiate translation and investigated possible interactions between the IRES and core coding sequences by using a dual luciferase reporter assay. Our results suggest that such long-range interactions within the viral genome can affect IRES-driven translation. Moreover, the significance of a possible miR-122 binding to the BovHepV IRES was investigated. When analyzing translation in human Huh-7 cells with large amounts of endogenous miR-122, introduction of point mutations to the miR-122 binding site resulted in reduced translation efficiency. Similar results were observed in HeLa cells after substitution of miR-122. Nevertheless, the absence of pronounced effects in a bovine hepatocyte cell line expressing hardly any miR-122 as well suggests additional functions of this host factor in virus replication.IMPORTANCE Several members of the family Flaviviridae, including HCV, have adapted cap-independent translation strategies to overcome canonical eukaryotic translation pathways and use cis-acting RNA-elements, designated viral internal ribosome entry sites (IRES), to initiate translation. Although novel hepaciviruses have been identified in different animal species, only limited information is available on their biology on molecular level. Therefore, our aim was a fundamental analysis of BovHepV IRES functions. The findings which show that functional IRES elements are also crucial for BovHepV translation expand our knowledge on molecular mechanism of hepacivirus propagation. We also studied the possible effects of one major host factor implicated in HCV pathogenesis, miR-122. The results of mutational analyses suggested that miR-122 enhances virus translation mediated by BovHepV IRES.

Circulating microRNA-122 levels are important predictor of hepatitis B virus surface antigen seroclearance

It is currently unclear what impact serum microRNA-122 (miR-122) levels have on clearance of hepatitis B virus (HBV) surface antigen (HBsAg) in HBV-infected patients who had not received antiviral therapy. The current study evaluated the impact of serum miR-122 levels on HBsAg seroclearance in 367 consecutive HBV-infected patients who had not received antiviral therapy between their initial and last visit, and investigated the predictive factors of HBsAg seroclearance. Cumulative HBsAg seroclearance rates were 13.5%, 32.0%, and 37.4% after 10, 20, and 30 years, respectively. The yearly incidence of HBsAg seroclearance over the investigated 30-year period was 1.25%. A significant and strong correlation was observed between serum miR-122 and HBsAg levels. Moreover, there was a significant correlation between serum miR-122 levels and the levels of HBV DNA, hepatitis B e-antigen, and HBV core-related antigen. The HBsAg seroclearance rate in patients with a <1.0-fold change of serum miR-122 levels was significantly higher than in those with a ≥1.0-fold change. Multivariate analysis identified age (≥30 years), HBV DNA levels (<2.2 log U/mL), HBV genotype (non-C), and serum miR-122 levels (<1.0-fold change) as significant predictors of HBsAg seroclearance. Our results indicated that serum miR-122 level is an important predictor of HBsAg seroclearance in Japanese patients who do not receive antiviral therapy. Understanding the complexity of the interactions among various virus-related and host-related factors could potentially help in the design of new therapies that enhance HBsAg seroclearance.

Association of circulating microRNA-122 with presence and severity of atherosclerotic lesions

Objective

MicroRNA (miR)-122 is highly expressed in the liver, where it has been implicated as a regulator of fatty-acid metabolism. A recent study reported that miR-122 plays a role in pathogenesis of atherosclerosis; however, whether it connects with severity of atherosclerotic lesion is still controversial. We therefore investigated the association between miR-122 expression and presence and severity of coronary atherosclerotic plaque.

Methods

During January–November 2017, we included 300 patients with coronary heart disease (CHD) and 100 subjects as the control group. MiR-122 content was detected by quantitative real-time polymerase chain reaction. MiR-122 level was identified in all subjects, and the Spearman correlation between miR-122 and severity of atherosclerosis was analyzed.

Results

Patients with CHD had higher miR-122 expression than in control group (2.61, 0.91–8.86 vs. 1.62, 0.71–3.45, p < 0.001). Gensini score was significantly associated with miR-122 expression (r = 0.7964, p < 0.001). The odds ratio of miR-122 solely was 0.12 (95% CI [0.05–0.43]) and factors such as cholesterol, triglyceride together with miR-122 level were closely associated with atherosclerosis (all p < 0.001).

Conclusions

The serum level of miR-122 may be used to differentiate between mild and severe coronary atherosclerotic lesion. Use of this marker might allow non-invasive diagnosis the degree of coronary atherosclerosis.

Prenatal Exposure to a Maternal High Fat Diet Increases Hepatic Cholesterol Accumulation in Intrauterine Growth Restricted Rats in Part Through MicroRNA-122 Inhibition of Cyp7a1

Intrauterine growth restriction (IUGR) and consumption of a high saturated fat diet (HFD) increase the risk of hypercholesterolemia, a leading cause of morbidity and mortality. The mechanism through which the cumulative impact of IUGR and in utero exposure to a maternal HFD increase cholesterol levels remains unknown. Cholesterol 7α hydroxylase (Cyp7a1) initiates catabolism of cholesterol to bile acids for elimination from the body, and is regulated by microRNA-122 (miR-122). We hypothesized that IUGR rats exposed to a maternal HFD would have increased cholesterol and decreased Cyp7a1 protein levels in juvenile rats, findings which would be normalized by administration of a miR-122 inhibitor. To test our hypothesis we used a rat model of surgically induced IUGR and fed the dams a regular diet or a HFD from prior to conception through lactation. At the time of weaning, IUGR female rats exposed to a maternal HFD had increased hepatic cholesterol, decreased hepatic Cyp7a1 protein and hepatic bile acids, and increased hepatic miR-122 compared to non-IUGR rats exposed to the same HFD. In vivo inhibition of miR-122 increased hepatic Cyp7a1 protein and decreased hepatic cholesterol. Our findings suggest that IUGR combined with a maternal HFD decreased cholesterol catabolism to bile acids, in part, via miR-122 inhibition of Cyp7a1.

Coptisine from Rhizoma coptidis exerts an anti-cancer effect on hepatocellular carcinoma by up-regulating miR-122

With increasing incidence and mortality, hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. In this study, microRNA-122 (miR-122) mimics and relevant control oligonucleotides were transfected into HepG2 cells in vitro, followed by coptisine (COP) and sorafenib treatments. Cell proliferation, migration, and apoptosis were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and colony formation assay, wound-healing assay, Hoechst 33258 staining and flow cytometry, respectively. Histopathology and miR-122 were analyzed by haemotoxylin and eosin (H&E) staining and real-time RT-PCR, respectively; whereas, the relevant protein expressions were detected by western blot. In vivo, COP enhanced the expression of miR-122 by 160% compared to control in male BALB/c nude mice; COP not only protected the liver morphology but also showed a significant anti-cancer effect. Further, there was no remarkable difference between the tumor weights in the COP and sorafenib groups, but there was a striking difference to the tumor control group (p < 0.05). Hence, COP inhibited the proliferation, migration and promoted apoptosis of HCC cells; moreover, it inhibited the tumor growth in nude mice by up-regulating the expression of miR-122.

Signals Involved in Regulation of Hepatitis C Virus RNA Genome Translation and Replication

Hepatitis C virus (HCV) preferentially replicates in the human liver and frequently causes chronic infection, often leading to cirrhosis and liver cancer. HCV is an enveloped virus classified in the genus Hepacivirus in the family Flaviviridae and has a single-stranded RNA genome of positive orientation. The HCV RNA genome is translated and replicated in the cytoplasm. Translation is controlled by the Internal Ribosome Entry Site (IRES) in the 5' untranslated region (5' UTR), while also downstream elements like the cis-replication element (CRE) in the coding region and the 3' UTR are involved in translation regulation. The cis-elements controlling replication of the viral RNA genome are located mainly in the 5'- and 3'-UTRs at the genome ends but also in the protein coding region, and in part these signals overlap with the signals controlling RNA translation. Many long-range RNA-RNA interactions (LRIs) are predicted between different regions of the HCV RNA genome, and several such LRIs are actually involved in HCV translation and replication regulation. A number of RNA cis-elements recruit cellular RNA-binding proteins that are involved in the regulation of HCV translation and replication. In addition, the liver-specific microRNA-122 (miR-122) binds to two target sites at the 5' end of the viral RNA genome as well as to at least three additional target sites in the coding region and the 3' UTR. It is involved in the regulation of HCV RNA stability, translation and replication, thereby largely contributing to the hepatotropism of HCV. However, we are still far from completely understanding all interactions that regulate HCV RNA genome translation, stability, replication and encapsidation. In particular, many conclusions on the function of cis-elements in HCV replication have been obtained using full-length HCV genomes or near-full-length replicon systems. These include both genome ends, making it difficult to decide if a cis-element in question acts on HCV replication when physically present in the plus strand genome or in the minus strand antigenome. Therefore, it may be required to use reduced systems that selectively focus on the analysis of HCV minus strand initiation and/or plus strand initiation.

Functional sequestration of microRNA-122 from Hepatitis C Virus by circular RNA sponges

Circular RNAs (circRNAs) were recently described as a novel class of cellular RNAs. Two circRNAs were reported to function as molecular sponges, sequestering specific microRNAs, thereby de-repressing target mRNAs. Due to their elevated stability in comparison to linear RNA, circRNAs may be an interesting tool in molecular medicine and biology. In this study, we provide a proof-of-principle that circRNAs can be engineered as microRNA sponges. As a model system, we used the Hepatitis C Virus (HCV), which requires cellular microRNA-122 for its life cycle. We produced artificial circRNA sponges in vitro that efficiently sequester microRNA-122, thereby inhibiting viral protein production in an HCV cell culture system. These circRNAs are more stable than their linear counterparts, and localize both to the cytoplasm and to the nucleus, opening up a wide range of potential applications.

Inducible microRNA-122 modulates RIG-I signaling pathway via targeting DAK in miiuy croaker after poly(I:C) stimulation

MicroRNA-122 (miR-122) was originally identified in mouse and then lots of researches on miR-122 had been performed in mammals. However, the functional study of miR-122 were restricted in fish. In miiuy croaker, miR-122 is sensitive to poly(I:C) stimulation. In this study, a combination of bioinformatics and experimental techniques were used to investigate the functions of miR-122. DAK is a putative target gene of miR-122 which was predicted by bioinformatics, and further the luciferase reporter assays were used to confirm the target sites in DAK 3'untranslated region. The inhibiting effect of miR-122 mimics or pre-miR-122 on DAK presented the dose and time dependent manners, and the pre-miR-122 showed stronger inhibiting effect on DAK than the miR-122 mimics. Therefore, the miR-122 participate in regulating RIG-I-like receptors signaling pathway via inhibiting DAK which is the inhibitors of MDA5. The expression of miR-122 and DAK showed negative relationship in both miiuy croaker spleen and macrophages, which imply that miR-122 may regulate DAK at the post-transcriptional level. These results will enhance our understanding about the regulation of miRNAs on immune response in fish.

Protective effect of Coptisine from Rhizoma Coptidis on LPS/D-GalN-induced acute liver failure in mice through up-regulating expression of miR-122

Coptisine (COP), one of the main active ingredients of Rhizoma Coptidis, reportedly has anti-inflammatory, anti-colon cancer properties, but it remains elusive whether COP owns hepatoprotective activity. Mice were pretreated with COP for 7d prior to lipopolysaccharide/d-galactosamine (LPS/D-GalN) administration to detect the hepatic protective effects of COP. The mechanism was explored in using HepG2 cells with low level of miR-122 and LO2 cells with high level of miR-122, combining with miR-122 agomir transfection by means of detecting the expression of miR-122 and proteins, clinical index and apoptosis. COP ameliorated the LPS/D-GalN-induced liver failure by lowering serum levels of ALT and AST, raising hepatic GSH and SOD levels, and maintaining the morphology of hepatocytes, along with an increase in miR-122 expression in mice. The results in vitro indicated that, after miR-122 mimic administration, the alone treatment of COP and the co-treatment of COP and LPS transfection obviously promoted the apoptosis of HepG2, which was increased by 152.67% and 113.97% compared with NC (P < 0.05 vs NC). LPS significantly induced the apoptosis of L02 cells, but COP treatment attenuated that of L02 cells. Further analysis showed that COP increased the miR-122 level and the expression of Bax, cleaved-casp3 and decreased Bcl-2, Bcl-xL in LPS-treated HepG2 cells. COP increased the miR-122 level but decreased the expression of TLR4, Bcl-2, Bcl-xL in LPS-treated L02 cells. COP attenuated LPS/D-GalN-induced ALF by up-regulating the level of miR-122, synergistically promoting apoptosis, and suggesting COP which showed a potential protective effect on ALF.

Decreased expression of microRNA-122 is associated with an unfavorable prognosis in childhood acute myeloid leukemia and function analysis indicates a therapeutic potential

MicroRNA (miR)-122 functions as a tumor suppressor in various human cancers. However, its involvement in childhood acute myeloid leukemia (AML) remains unknown. In this study, quantitative real-time PCR assay demonstrated that miR-122 expression in bone marrow specimens from AML children were significantly lower than that in non-malignant controls (P<0.001). Statistically, AML children with low miR-122 expression more frequently had large white blood cell count (P=0.022), French-American-British classification subtype M7 (P<0.001), unfavorable cytogenetics (P=0.002) and day 7 response to the treatment (P=0.036), short relapse-free (P=0.001) and overall (P=0.008) survivals than those with high expression. Multivariate analysis also determined that miR-122 expression was an independent prognostic factor for both relapse-free and overall survivals. Functionally, the enforced expression of miR-122 in AML cell lines efficiently suppressed cell proliferation and reduced the ratio of S-phase cells in vitro (all P<0.05). In conclusion, the abnormal expression of miR-122 may be a marker of the aggressive progression in childhood AML. Importantly, its downregulation may serve as a prognostic factor to predict poor outcome. Our study also reveal that miR-122 may function as a tumor suppressor in childhood AML, highlighting a new therapeutic strategy for this malignancy.

Plasma micoRNA-122 as a predictive marker for treatment response following transarterial chemoembolization in patients with hepatocellular carcinoma

BACKGROUND AND AIM

Circulating microRNA (miR)-122 has recently been investigated as a potential biomarker of various hepatic diseases, such as chronic hepatitis and hepatocellular carcinoma (HCC). We investigated the association between plasma miR-122 levels and the treatment outcomes following transarterial chemoembolization (TACE) in HCC patients.

METHODS

We included 177 HCC patients treated with TACE in the study; TACE refractoriness and liver transplantation-free survival were evaluated during follow up. Pretreatment plasma miR-122 levels were assessed using quantitative real-time polymerase chain reaction. Relative quantification of miR-122 expression (fold change) was determined using the 2^(-ΔΔCt) method. MiR-16 was used as an internal control for the normalization of miRNA data.

RESULTS

During the mean follow up of 22.4 (range, 1-79) months, 112 (69.5%) patients exhibited TACE refractoriness. Multivariate analyses showed that tumor number (hazard ratio [HR], 2.51; 95% confidence interval [CI], 1.43-4.41; P = 0.001) and tumor size (HR, 2.65; 95% CI, 1.62-4.32; P = 0.000) can independently predict overall TACE refractoriness. High miR-122 expression (> 100) was associated with early TACE refractoriness (within 1 year; HR, 2.77; 95% CI, 1.12-6.86; P = 0.028), together with tumor number (HR, 22.73; 95% CI, 2.74-188.66; P = 0.004) and tumor size (HR, 4.90; 95% CI, 1.99-12.06; P = 0.001). Univariate analyses showed that high miR-122 expression tends to be associated with poor liver transplantation-free survival (HR, 1.42; 95% CI, 0.95-2.11; P = 0.085). However, it was statistically insignificant in multivariate analysis.

CONCLUSION

High expression levels of plasma miR-122 are associated with early TACE refractoriness in HCC patients treated with TACE.

Analysis of association between circulating miR-122 and histopathological features of nonalcoholic fatty liver disease in patients free of hepatocellular carcinoma

Background

The association between circulating microRNA-122 (miR-122) and histopathological features of nonalcoholic fatty liver disease (NAFLD) remains unclear.

Methods

The association of serum miR-122 levels with histopathological features of NAFLD (steatosis, ballooning, lobular inflammation, and stage, as histological components of nonalcoholic steatohepatitis) was examined in serial liver biopsies from 36 hepatocellular carcinoma (HCC)-free Japanese patients with histopathologically-proven NAFLD. The median interval between first and second liver biopsies was 4.6 years.

Results

In patients who showed improvement of histopathological scores (steatosis, ballooning, and stage), serum miR-122 levels were significantly lower at second biopsy than first biopsy. In patients who showed no improvement, the changes at second biopsy were not different from those at first biopsy. There were significant and strong associations between serum miR-122 ratio (ratio of level at second biopsy to that at first biopsy) and changes in histopathological scores (of steatosis, lobular inflammation, and stage). There were also significant and strong associations between serum miR-122 ratio and changes in other clinical parameters, including aspartate aminotransferase and alanine aminotransferase.

Conclusions

Longitudinal examination of serial liver biopsies showed the association of serum miR-122 with histopathological features of HCC-free NAFLD patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-016-0557-6) contains supplementary material, which is available to authorized users.

Crosstalk between microRNA-122 and FOX family genes in HepG2 cells

MicroRNA-122 (miR-122) is liver specific and plays an important role in physiology as well as diseases including hepatocellular carcinoma (HCC). Downregulation of miR-122 in HCC modulates apoptosis. Similarly, the putative targets of miR-122, the forkhead box (FOX) family genes also play an important role in the regulation of apoptosis. Hence, an interplay between miR-122 and FOX family genes has been explored in this study. Initially, an augmentation of apoptosis was noticed in HepG2 cells after transfection with miR-122. Further, the predicted miR-122 targets, the FOX family genes ( FOXM1b, FOXP1, and FOXO4) were selected via in silico analysis based on their role in apoptosis. We checked the expression of all these genes at transcript level after the transfection of miR-122 and found that the relative expression of FOXP1 and FOXM1b was significantly downregulated (p < 0.005) and that of FOXO4 was upregulated (p < 0.005). Thus, the finding indicates deregulation of these FOX genes as a result of miR-122 augmentation might be involved in the modulation of apoptosis.

Elevating microRNA-122 in blood improves outcomes after temporary middle cerebral artery occlusion in rats

Because our recent studies have demonstrated that miR-122 decreased in whole blood of patients and in whole blood of rats following ischemic stroke, we tested whether elevating blood miR-122 would improve stroke outcomes in rats. Young adult rats were subjected to a temporary middle cerebral artery occlusion (MCAO) or sham operation. A polyethylene glycol-liposome-based transfection system was used to administer a miR-122 mimic after MCAO. Neurological deficits, brain infarction, brain vessel integrity, adhesion molecule expression and expression of miR-122 target and indirect-target genes were examined in blood at 24 h after MCAO with or without miR-122 treatment. miR-122 decreased in blood after MCAO, whereas miR-122 mimic elevated miR-122 in blood 24 h after MCAO. Intravenous but not intracerebroventricular injection of miR-122 mimic decreased neurological deficits and brain infarction, attenuated ICAM-1 expression, and maintained vessel integrity after MCAO. The miR-122 mimic also down-regulated direct target genes (e.g. Vcam1, Nos2, Pla2g2a) and indirect target genes (e.g. Alox5, Itga2b, Timp3, Il1b, Il2, Mmp8) in blood after MCAO which are predicted to affect cell adhesion, diapedesis, leukocyte extravasation, eicosanoid and atherosclerosis signaling. The data show that elevating miR-122 improves stroke outcomes and we postulate this occurs via downregulating miR-122 target genes in blood leukocytes.