Impact of circulating miR-122 for histological features and hepatocellular carcinoma of nonalcoholic fatty liver disease in Japan. Hepatol Int. 2016;10:647-656. [PMID: 27074850 DOI: 10.1007/s12072-016-9729-2]

A review on cell-free RNA profiling: Insights into metabolic diseases and predictive value for bariatric surgery outcomes

BACKGROUND

The advent of liquid biopsies presents a novel, minimally invasive methodology for the detection of disease biomarkers, offering a significant advantage over traditional biopsy techniques. Particularly, the analysis of cell-free RNA (cfRNA) has garnered interest due to its dynamic expression profiles and the capability to study various RNA species, including messenger RNA (mRNA) and long non-coding RNA (lncRNA). These attributes position cfRNA as a versatile biomarker with broad potential applications in clinical research and diagnostics.

SCOPE OF REVIEW

This review delves into the utility of cfRNA biomarkers as prognostic tools for obesity-related comorbidities, such as diabetes, dyslipidemia, and non-alcoholic fatty liver disease.

MAJOR CONCLUSIONS

We evaluate the efficacy of cfRNA in forecasting metabolic outcomes associated with obesity and in identifying patients likely to experience favorable clinical outcomes following bariatric surgery. Additionally, this review synthesizes evidence from studies examining circulating cfRNA across different physiological and pathological states, with a focus on its role in diabetes, including disease progression monitoring and treatment efficacy assessment. Through this exploration, we underscore the emerging relevance of cfRNA signatures in the context of obesity and its comorbidities, setting the stage for future investigative efforts in this rapidly advancing domain.

Non-invasive biomarkers prognostic of decompensation events in NASH cirrhosis: a systematic literature review

Liver cirrhosis due to nonalcoholic steatohepatitis (NASH) is a life-threatening condition with increasing incidence world-wide. Although its symptoms are unspecific, it can lead to decompensation events such as ascites, hepatic encephalopathy, variceal hemorrhage, and hepatocellular carcinoma (HCC). In addition, an increased risk for cardiovascular events has been demonstrated in patients with NASH. Pharmacological treatments for NASH cirrhosis are not yet available, one of the reasons being the lack in surrogate endpoints available in clinical trials of NASH cirrhosis. The feasibility of non-invasive prognostic biomarkers makes them interesting candidates as possible surrogate endpoints if their change following treatment would result in better outcomes for patients in future clinical trials of NASH cirrhosis. In this systematic literature review, a summary of the available literature on the prognostic performance of non-invasive biomarkers in terms of cardiovascular events, liver-related events, and mortality is outlined. Due to the scarcity of data specific for NASH cirrhosis, this review includes studies on NAFLD whose evaluation focuses on cirrhosis. Our search strategy identified the following non-invasive biomarkers with prognostic value in studies of NASH patients: NAFLD fibrosis score (NFS), Fibrosis-4 (FIB-4), aspartate aminotransferase (AST) to platelet ratio index (APRI), enhanced liver fibrosis (ELF™), BARD (BMI, AST/ALT (alanine aminotransferase) ratio, diabetes), Hepamet Fibrosis Score (HFS), liver enzymes (AST + ALT), alpha-fetoprotein, platelet count, neutrophil to lymphocyte ratio (NLR), Lysyl oxidase-like (LOXL) 2, miR-122, liver stiffness, MEFIB (liver stiffness measured with magnetic resonance elastography (MRE) + FIB-4), and PNPLA3 GG genotype. The aim of the present systematic literature review is to provide the reader with a summary of the non-invasive biomarkers with prognostic value in NASH cirrhosis and give an evaluation of their utility as treatment monitoring biomarkers in future clinical trials.

Effect of fish oil supplementation on the concentration of miRNA-122, FGF-21 and liver fibrosis in patients with NAFLD: Study protocol for a randomized, double-blind and placebo-controlled clinical trial

BACKGROUND & AIMS

To date, no specific drugs are available for non-alcoholic fatty liver disease (NAFLD), though the effect of fish oil supplementation on improving fibrosis in patients with NAFLD has been evaluated. N-3 polyunsaturated fatty acids (n-3 PUFA) may modulate the concentration of microRNAs (miRNAs) and fibroblast growth factor (FGF)-21, which have been identified as non-invasive markers of liver fibrosis. The present study aims to evaluate whether n-3 PUFA supplementation can modulate miRNA-122 and FGF-21 and improve liver fibrosis and steatosis, measured by transient hepatic elastography (THE), in individuals with NAFLD.

METHODS

A randomized, double-blind, placebo-controlled clinical trial will be conducted to evaluate the effect of 4 g/day supplementation of fish oil (2100 mg EPA and 924 mg DHA) in patients with NAFLD over a 6-month period. Fifty-two patients aged >19 years will be randomly assigned to either a placebo (olive oil) or treatment (fish oil) group. Anthropometric data, food intake, physical activity, body composition, resting energy expenditure (evaluated using indirect calorimetry), liver enzymes, platelets, lipids and glucose profile, inflammatory markers (such as C-reactive protein, neutrophil/lymphocyte, platelet/lymphocyte, and monocyte/lymphocyte ratios), miRNA-122 and FGF-21 concentration, and incorporation of fatty acids into the erythrocyte membrane (analyzed using gas chromatography) as well as the degree of liver fibrosis and steatosis assessed using THE (Fibroscan® Touch 502, Paris, France) and liver biomarkers Steato-Brazilian Longitudinal Study of Adult Health, Fatty Liver Index, NAFLD Fibrosis Score, Fibrosis-4 score, and FibroScan-AST score will be evaluated at the beginning and end of the treatment. Continuous variables with normal distribution will be compared between placebo and intervention groups using Student's T test for independent samples; continuous non-parametric variables will be compared using Dunn or Mann-Whitney test. Associations between categorical variables will be analyzed using the chi-square test, and within-group differences will be evaluated using the Wilcoxon signed-ranks test. The criterion for determining significance will be set at 5%.

CONCLUSION

The present study protocol will investigate the supplementation of EPA-rich fish oil as an alternative treatment for NAFLD and its feasibility in affecting the concentration of miRNA-122 and FGF-21 markers. Its findings will offer valuable contributions to the literature.

REGISTRATION

ReBEC number RBR-8dp876.

Circulating miR-122-5p, miR-92a-3p, and miR-18a-5p as Potential Biomarkers in Human Liver Transplantation Follow-Up

The requirement of blood-circulating sensitive biomarkers for monitoring liver transplant (LT) is currently a necessary step aiming at the reduction of standard invasive protocols, such as liver biopsy. In this respect, the main objective of this study is to assess circulating microRNA (c-miR) changes in recipients' blood before and after LT and to correlate their blood levels with gold standard biomarkers and with outcomes such as rejection or complications after graft. An miR profile was initially performed; then, the most deregulated miRs were validated by RT-qPCR in 14 recipients pre- and post-LT and compared to a control group of 24 nontransplanted healthy subjects. MiR-122-5p, miR-92a-3p, miR-18a-5p, and miR-30c-5p, identified in the validation phase, were also analyzed considering an additional 19 serum samples collected from LT recipients and focusing on different follow-up (FU) times. The results showed significant, FU-related changes in c-miRs. In particular, miR-122-5p, miR-92a-3p, and miR-18a-5p revealed the same trend after transplantation and an increase in their level was found in patients with complications, independently from FU times. Conversely, the variations in the standard haemato-biochemical parameters for liver function assessment were not significant in the same FU period, confirming the importance of c-miRs as potential noninvasive biomarkers for monitoring patients' outcomes.

The Implications of Noncoding RNAs in the Evolution and Progression of Nonalcoholic Fatty Liver Disease (NAFLD)-Related HCC

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver pathology worldwide. Meanwhile, liver cancer represents the sixth most common malignancy, with hepatocellular carcinoma (HCC) as the primary, most prevalent subtype. Due to the rising incidence of metabolic disorders, NAFLD has become one of the main contributing factors to HCC development. However, although NAFLD might account for about a fourth of HCC cases, there is currently a significant gap in HCC surveillance protocols regarding noncirrhotic NAFLD patients, so the majority of NAFLD-related HCC cases were diagnosed in late stages when survival chances are minimal. However, in the past decade, the focus in cancer genomics has shifted towards the noncoding part of the genome, especially on the microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), which have proved to be involved in the regulation of several malignant processes. This review aims to summarize the current knowledge regarding some of the main dysregulated, noncoding RNAs (ncRNAs) and their implications for NAFLD and HCC development. A central focus of the review is on miRNA and lncRNAs that can influence the progression of NAFLD towards HCC and how they can be used as potential screening tools and future therapeutic targets.

NAFLD and Vitamin D: Evidence for Intersection of MicroRNA Regulated Pathways

Non-alcoholic fatty liver disease (NAFLD) is now the most common cause of chronic liver disease, worldwide. The molecular pathogenesis of NAFLD is complex, involving numerous signalling molecules including microRNAs (miRNAs). Dysregulation of miRNA expression is associated with hepatic inflammation, fibrosis and hepatocellular carcinoma. Although miRNAs are also critical to the cellular response to vitamin D, mediating regulation of the vitamin D receptor (VDR) and vitamin D’s anticancer effects, a role for vitamin D regulated miRNAs in NAFLD pathogenesis has been relatively unexplored. Therefore, this review aimed to critically assess the evidence for a potential subset of miRNAs that are both dysregulated in NAFLD and modulated by vitamin D. Comprehensive review of 89 human studies identified 25 miRNAs found dysregulated in more than one NAFLD study. In contrast, only 17 studies, including a protocol for a trial in NAFLD, had examined miRNAs in relation to vitamin D status, response to supplementation, or vitamin D in the context of the liver. This paper summarises these data and reviews the biological roles of six miRNAs (miR-21, miR-30, miR-34, miR-122, miR-146, miR-200) found dysregulated in multiple independent NAFLD studies. While modulation of miRNAs by vitamin D has been understudied, integrating the data suggests seven vitamin D modulated miRNAs (miR-27, miR-125, miR-155, miR-192, miR-223, miR-375, miR-378) potentially relevant to NAFLD pathogenesis. Our summary tables provide a significant resource to underpin future hypothesis-driven research, and we conclude that the measurement of serum and hepatic miRNAs in response to vitamin D supplementation in larger trials is warranted.

Dynamics of Circulating miR-122 Predict Liver Cancer and Mortality in Japanese Patients with Histopathologically Confirmed NAFLD and Severe Fibrosis Stage

INTRODUCTION

It is unclear whether the relationships between changes in fibrosis and circulating microRNA-122 (miR-122) dynamics might influence the prognosis of nonalcoholic fatty liver disease (NAFLD).

METHODS

This study investigates the impact of serum miR-122 dynamics and histological changes on the incidence of liver cancer and mortality in 81 Japanese NAFLD patients who underwent serial liver biopsies. The median interval between the first and second liver biopsies was 2.9 years.

RESULTS

The fibrosis stage scores indicated progression, no change, and improvement (a decrease of one point or more) in 21.0%, 56.8%, and 22.2% of the patients, respectively. There were 64 patients in the high-risk group who had no improvement in stage scores. Among these, the miR-122 levels were significantly lower in 7 patients with liver cancer than those of the 54 patients who had no liver cancer at the second liver biopsy. The cumulative rates of liver cancer were significantly higher in cases with miR-122 ratios <0.5 (serum miR-122 level at second biopsy to that at first biopsy) than those with ratios ≥0.5. The cumulative survival rates in cases with miR-122 ratios <0.5 tended to be lower than those with ratios ≥0.5. Of the 64 high-risk patients, 39 indicated stage 2 or greater (severe fibrosis stage) at the first liver biopsy and also showed similar results of cumulative liver cancer and survival rates.

CONCLUSIONS

Longitudinal examination of serial liver biopsies indicated that the circulating miR-122 dynamics might be useful in predicting the prognosis for NAFLD patients with severe fibrosis stage and no improvement of the stage scores.

Bioinformatic Analysis of Crosstalk Between circRNA, miRNA, and Target Gene Network in NAFLD

Background: The majority of chronic liver disease is caused by non-alcoholic fatty liver disease (NAFLD), which is one of the highly prevalent diseases worldwide. The current studies have found that non-coding RNA (ncRNA) plays an important role in the NAFLD, but few studies on circRNA. In this study, genes, microRNA (miRNA), and circular RNA (circRNA) associated with NAFLD were found by bioinformatic methods, bringing a novel perspective for the prevention and treatment of NAFLD.

Methods: Expression data of GSE63067 was acquired from Gene Expression Omnibus (GEO) database. The liver samples were collected from the people diagnosed with NAFLD or not. Differentially expressed genes (DEGs) were obtained from the steatosis vs. the control group and non-alcoholic steatohepatitis (NASH) vs. the control group using the GEO2R online tool. The overlapping genes remained for further functional enrichment analysis and protein-protein interaction network analysis. MiRNAs and circRNAs targeting these overlapping DEGs were predicted from the databases. Finally, the GSE134146 dataset was used to verify the expression of circRNA.

Results: In summary, 228 upregulated and 63 downregulated differential genes were selected. The top 10 biological processes and relative signaling pathways of the upregulated differential genes were obtained. Also, ten hub genes were performed in the Protein-protein interaction (PPI) network. One hundred thirty-nine miRNAs and 902 circRNAs were forecast for the differential genes by the database. Ultimately, the crosstalk between hsa_circ_0000313, miR-6512-3p, and PEG10 was constructed.

Conclusion: The crosstalk of hsa_circ_0000313-hsa-miR-6512-3p-PEG10 and some related non-coding RNAs may take part in NAFLD’s pathogenesis, which could be the potential biomarkers of NAFLD in the future.

Anti-cancer activity of two novel heterocyclic compounds through modulation of VEGFR and miR-122 in mice bearing Ehrlich ascites carcinoma

Metastasis in breast cancer is a leading cause of mortality among women in many countries. This study investigated the anti-cancer role of benzoimidazoquinazoline and benzimidazotriazin; two novel compounds that were designed, synthesized, structurally elucidated, and biologically evaluated as potent anti-angiogenic agents that act through inhibition of vascular endothelial growth factor receptor-2 (VEGFR2). Breast cancer was induced by inoculation of Ehrlich Ascites Carcinoma (EAC) cells. Seventy swiss albino mice were randomly divided into 7 groups, 10 animals each: (1) normal, (2) control EAC group, (3) cisplatin treated group, (4&5) benzoimidazoquinazoline treated (5 mg/kg and 10 mg/kg), (6&7) benzimidazotriazin treated (5 mg/kg and 10 mg/kg). The expression of miR-122 was assessed in the tumor tissue by quantitative PCR, and the VEGF level was determined in serum by ELISA. VEGFR2 and cluster of differentiation (CD)34 were assessed by immunohistochemistry. Serum ALT, AST, creatinine, and urea were measured. Treatment with benzoimidazoquinazoline and benzimidazotriazin decreased tumor weight and serum levels of VEGF, and down-regulated expression of VEGFR2 and CD34 in the tumor tissue. miR-122 was upregulated, particularly in the benzimidazotriazin (10 mg/kg) group. Relative to cisplatin, the novel compounds were less toxic to kidneys. Benzoimidazoquinazoline and benzimidazotriazin are promising anti-cancer agents that act through inhibition of angiogenesis and thus provide a new strategy for advancement of chemotherapy.

High-intensity interval training (HIIT) alleviated NAFLD feature via miR-122 induction in liver of high-fat high-fructose diet induced diabetic rats

Background: Exercise intervention is strongly recommended to manage metabolic diseases. In this study, we investigate, whether HIIT and CET can induce hepatic miR-122 expression, NAFLD rats with diabetes.Methods: 40 Wistar rats divided into 2 groups, non-diabetic (NDC) and diabetic .Type 2 diabetes was induced by high-fat high-fructose diet (HFHFD). Then diabetic rats were subdivided into three groups: diabetic control (HFHFD + DC), CET (HFHFD + CET), and HIIT (HFHFD + HIIT). After eight weeks of exercise on a rodent treadmill, we measured miR-122 and its target genes expression in the liver of rats.Results: HIIT decreased the expression of FAS, ACC, SREBP-1c compared with HFHFD + DC (p = .004, p = .032, p = .043, respectively), and could partially increase miR-122 expression as compared with HFHFD + DC (26.8%, p = .68).Conclusions: Exercise training could be a non-pharmacological intervention for improvement of NAFLD of diabetic rats by induction of miR-122. HIIT had a greater effect on NAFLD amelioration than CET.

Role of Extracellular Vesicles in the Pathophysiology, Diagnosis and Tracking of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, affecting approximately one-third of the global population. Most affected individuals experience only simple steatosis—an accumulation of fat in the liver—but a proportion of these patients will progress to the more severe form of the disease, non-alcoholic steatohepatitis (NASH), which enhances the risk of cirrhosis and hepatocellular carcinoma. Diagnostic approaches to NAFLD are currently limited in accuracy and efficiency; and liver biopsy remains the only reliable way to confirm NASH. This technique, however, is highly invasive and poses risks to patients. Hence, there is an increasing demand for improved minimally invasive diagnostic tools for screening at-risk individuals and identifying patients with more severe disease as well as those likely to progress to such stages. Recently, extracellular vesicles (EVs)—small membrane-bound particles released by virtually all cell types into circulation—have emerged as a rich potential source of biomarkers that can reflect liver function and pathological processes in NAFLD. Of particular interest to the diagnosis and tracking of NAFLD is the potential to extract microRNAs miR-122 and miR-192 from EVs circulating in blood, particularly when using an isolation technique that selectively captures hepatocyte-derived EVs.

Circulating MicroRNA-122 and Fibrosis Stage Predict Mortality of Japanese Patients With Histopathologically Confirmed NAFLD

The impact of circulating microRNA‐122 (miR‐122) on mortality in patients with histopathologically confirmed nonalcoholic fatty liver disease (NAFLD) remains unclear. We analyzed the overall survival rates in 441 Japanese patients with histopathologically confirmed NAFLD after a median follow‐up period of 4.7 years. We also determined the clinicopathologic, genetic, and epigenetic parameters, including serum miR‐122 levels, for prediction of mortality. Of the 441 study patients, 21 (4.8%) died during the follow‐up period. The cumulative survival rates were 95.4% and 90.6% at the end of 5 and 10 years, respectively. Multivariate analysis identified history of liver cancer (presence; hazard ratio [HR], 4.94; 95% confidence interval [CI], 1.84‐13.3), serum miR‐122 (<1.00 fold change; HR, 4.35; 95% CI, 0.06‐0.83), and fibrosis‐4 index (FIB‐4 index) (≥1.30; HR, 15.7; 95% CI, 2.01‐122) as significant risk factors of mortality. Cumulative survival rates varied significantly among patients with none/one risk factor, two risk factors, and three risk factors; particularly, the survival rate of patients with three risk factors was significantly lower than those with two risk factors and none/one risk factor. Two or more risk factors were identified in 17 of 21 (81.0%) death cases. Conclusion: The importance of serum miR‐122 and FIB‐4 index as risk factors for mortality in Japanese patients with histopathologically confirmed NAFLD is shown. Early diagnosis based on the presence of more than one risk factor and early treatment might improve the prognosis.

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.

DNA Methylation of miR-122 Aggravates Oxidative Stress in Colitis Targeting SELENBP1 Partially by p65NF-κB Signaling

Aberrant microRNA (miRNA) expressions contribute to the development and progression of various diseases, including Crohn's disease (CD). However, the accurate mechanisms of miRNAs in CD are definitely unclear. We employed colonic tissue samples from normal volunteers and CD patients, an acute mice colitis model induced by 2,4,6-trinitro-benzene-sulfonic acid (TNBS), and a cellular oxidative stress model induced by H₂O₂ in HT-29 cells to determine the effects of oxidative stress on expressions of miR-122, selenium-binding protein 1 (SELENBP1, SBP1), p65 nuclear factor κB (p65NF-κB) signaling, and DNA methylation. We found that SBP1 was mainly located on epithelial cells and was significantly increased in patients with active CD. SBP1 was the target gene of miR-122. miR-122 expression was downregulated while SBP1 expression was upregulated under TNBS-induced colitis or oxidative stress. Pre-miR-122 or siRNA SBP1 (si-SBP1) treatment ameliorated acute TNBS-induced colitis and H₂O₂-induced oxidative stress. Cotreatment of pre-miR-122 and si-SBP1 enhanced these effects. Besides, pre-miR-122 and si-SBP1 obviously activated the p65NF-κB signaling by phosphorylation of IκBα. Bisulfite sequencing of the CpG islands in the promoter region of miR-122 showed that CpG methylation was significantly increased under oxidative stress. Treating cells with 5′-AZA which was well known as a DNA-demethylating agent significantly increased miR-122 expression. Our results suggest that oxidative stress-induced DNA methylation of miR-122 aggravates colitis targeting SELENBP1 partially by p65NF-κB signaling and may promote the progression of CD.

The Circulating Micro-RNAs (-122, -34a and -99a) as Predictive Biomarkers for Non-Alcoholic Fatty Liver Diseases

BACKGROUND

It remains essential for patient safety to develop non-invasive diagnostic tools to diagnose non-alcoholic fatty liver rather than invasive techniques.

AIM

Our case-control study was to address the value of circulating miRNAs as a potential non-invasive biomarker for the diagnosis of non-alcoholic fatty acid diseases (NAFLD) and monitoring of disease progression.

METHODS

Routine clinical assessment, laboratory tests, anthropometric study, and liver biopsy results reported for 210 patients with NAFLD (124 patients of simple steatosis (SS) and 86 of non-alcoholic steatohepatitis (NASH)). Apparently matched for age and gender, healthy participants (n= 90) were enrolled as a control group. Serum samples were tested for micro-RNAs (-122, -34a and -99a) by quantitative-PCR.

RESULTS

By histopathology, 124 of the NAFLD group were of SS and 86 patients were of NASH. Compared with the control subjects, both mi-RNA-122 and -34a levels were increased in NAFLD (p< 001) and at a cut-off = 1.261, mi-RNA-122 had 92% sensitivity, 85% specificity to differentiate NAFLD from healthy controls, while mi-RNA-99a were significantly decreased in NAFLD patients with an observed decrease in disease severity, and at a cut-off = 0.46, miRNA-99a had 94% sensitivity and 96% specificity to discriminate SS from NASH.

CONCLUSION

The integration of a circulating mi-RNA panel to diagnose NAFLD cases and to discriminate between SS and NASH. Large-scale study is still needed to verify the other mi-RNA profiles and their role in NAFLD pathogenesis and targeting therapy.

Adipose may actively delay progression of NAFLD by releasing tumor-suppressing, anti-fibrotic miR-122 into circulation

Nonalcoholic fatty liver disease (NAFLD) is the most common liver pathology. Here we propose tissue-cooperative, homeostatic model of NAFLD. During early stages of NAFLD the intrahepatic production of miR-122 falls, while the secretion of miRNA-containing exosomes by adipose increases. Bloodstream carries exosome to the liver, where their miRNA cargo is released to regulate their intrahepatic targets. When the deterioration of adipose catches up with the failing hepatic parenchyma, the external supply of liver-supporting miRNAs gradually tapers off, leading to the fibrotic decompensation of the liver and an increase in hepatic carcinogenesis. This model may explain paradoxical observations of the disease-associated decrease in intrahepatic production of certain miRNAs with an increase in their levels in serum. Infusions of miR-122 and, possibly, some other miRNAs may be efficient for preventing NAFLD-associated hepatocellular carcinoma. The best candidates for exosome-wrapped miRNA producer are adipose tissue-derived mesenchymal stem cells (MSCs), known for their capacity to shed large amounts of exosomes into the media. Notably, MSC-derived exosomes with no specific loading are already tested in patients with liver fibrosis. Carrier exosomes may be co-manufactured along with their cargo. Exosome-delivered miRNA cocktails may augment functioning of human organs suffering from a variety of chronic diseases.

miR‑122 promotes proliferation and invasion of clear cell renal cell carcinoma by suppressing Forkhead box O3

MicroRNAs (miRNAs) serve an important role in renal cancer, but renal cancer miRNA expression data remains inconsistent. Therefore, there is a requirement for integrated analysis of these data. An increasing number of studies demonstrate that miR‑122 is dysregulated in numerous cancer types, including liver, lung and breast cancer, yet its role in clear cell renal cell carcinoma (ccRCC) remains unclear. In the present study, an integrated analysis of four ccRCC miRNAs expression datasets was performed and the expression of miR‑122 in the present cohort was validated. The effects of cell proliferation, colony formation, migration and invasion of ccRCC cells in vitro were assayed following transfection with miR‑122 mimics and inhibitor. The target gene of miR‑122 was confirmed using a luciferase reporter assay, and a xenograft mouse model was used to determine the effect of miR‑122 in ccRCC tumorigenicity in vivo. The present results demonstrated that patients with ccRCC with an increased miR‑122 level in tumor tissues had a shortened metastasis‑free survival time as indicated by The Cancer Genome Atlas‑Kidney Renal Clear Cell Carcinoma dataset and the present ccRCC cohort. Overexpression of miR‑122 in 786‑O cells improved cell proliferation, colony formation, migration and invasion, while knockdown of miR‑122 in SN12‑PM6 cells inhibited cell growth, colony formation, migration and invasion. Western blot analysis and luciferase reporter assays were used to identify FOXO3 as a direct target of miR‑122. The present results indicate that miR‑122 serves a tumor‑promoting role by direct targeting FOXO3 in ccRCC.

Role of microRNAs in alcohol-induced liver disorders and non-alcoholic fatty liver disease

MicroRNAs (miRNAs) are small non-coding RNAs that regulate multiple physiological and pathological functions through the modulation of gene expression at the post-transcriptional level. Accumulating evidence has established a role for miRNAs in the development and pathogenesis of liver disease. Specifically, a large number of studies have assessed the role of miRNAs in alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD), two diseases that share common underlying mechanisms and pathological characteristics. The purpose of the current review is to summarize and update the body of literature investigating the role of miRNAs in liver disease. In addition, the potential use of miRNAs as biomarkers and/or therapeutic targets is discussed. Among all miRNAs analyzed, miR-34a, miR-122 and miR-155 are most involved in the pathogenesis of NAFLD. Of note, these three miRNAs have also been implicated in ALD, reinforcing a common disease mechanism between these two entities and the pleiotropic effects of specific miRNAs. Currently, no single miRNA or panel of miRNAs has been identified for the detection of, or staging of ALD or NAFLD. While promising results have been shown in murine models, no therapeutic based-miRNA agents have been developed for use in humans with liver disease.

Non-invasive prediction of NAFLD severity: a comprehensive, independent validation of previously postulated serum microRNA biomarkers

Liver biopsy is currently the only reliable method to establish nonalcoholic fatty liver disease (NAFLD) severity. However, this technique is invasive and occasionally associated with severe complications. Thus, non-invasive diagnostic markers for NAFLD are needed. Former studies have postulated 18 different serum microRNA biomarkers with altered levels in NAFLD patients. In the present study, we have re-examined the predictive value of these serum microRNAs and found that 9 of them (miR-34a, -192, -27b, -122, -22, -21, -197, -30c and -16) associated to NAFLD severity in our independent cohort. Moreover, miR-192, -27b, -22, -197 and -30c appeared specific for NAFLD, when compared with patients with drug-induced liver injury. Preliminary serum RNAseq analysis allowed identifying novel potential miRNA biomarkers for nonalcoholic steatohepatitis (NASH). The classification performance of validated miRNAs (and their ratios) for NASH was better than that reached by AST, whereas for advanced fibrosis prediction miRNAs did not perform better than the FIB-4 algorithm. Cross-validated models combining both clinical and miRNA variables showed enhanced predictivity. In conclusion, the circulating microRNAs validated demonstrate a better diagnostic potential than conventional serum markers to identify NASH patients and could complement and improve current fibrosis prediction algorithms. The research in this field is still open.

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.

Critical Roles of microRNAs in the Pathogenesis of Fatty Liver: New Advances, Challenges, and Potential Directions

In this review, we summarize the current understanding of microRNA (miRNA)-mediated modulation of the gene expression in the fatty liver as well as related signaling pathways. Because of the breadth and diversity of miRNAs, miRNAs may have a very wide variety of biological functions, and much evidence has confirmed that miRNAs are involved in the pathogenesis of fatty liver. In the pathophysiological mechanism of fatty liver, miRNAs may be regulated by upstream regulators, and have their own regulatory targets. miRNAs display important roles in the pathological mechanisms of alcoholic liver disease and non-alcoholic fatty liver disease. At present, most of the miRNA studies are focused on cell and tissue levels, and in vivo studies will help us elucidate the regulation of miRNAs and help us evaluate the potential of miRNAs as diagnostic markers and therapeutic targets. Furthermore, there is evidence that miRNAs are involved in the mechanism of natural medicine treatment in fatty liver. Given the important roles of miRNAs in the pathogenesis of fatty liver, we predict that studies of miRNAs in the pathogenesis of fatty liver will contribute to the elucidation of fatty liver pathology and the treatment of fatty liver patients.

Circulating levels of miR-122 and nonalcoholic fatty liver disease in pre-pubertal obese children

OBJECTIVES

The liver-specific miR-122 was proposed as biomarker for NAFLD in adults. Here, we investigated the relationship between miR-122 levels, parameters of liver metabolism and NAFLD in pre-pubertal obese children.

METHODS

Parameters of liver metabolism (ALT, AST and GGT) of three European cohorts were included (German cohort [n = 71; age: 11.53 ± 1.29 years; BMI z-score: 2.96 ± 0.64], Italian cohort [n = 45; age: 9.60 ± 2.11 years; BMI z-score: 3.57 ± 1.16], Slovenian cohort [n = 31; age: 7.53 ± 1.47 years; BMI z-score: 3.66 ± 0.88]). MiR-122 levels and CK18 concentrations were measured in fasting blood samples. In the German and Italian cohort, the diagnosis of NAFLD and grading of NAFLD was assessed by ultrasound.

RESULTS

NAFLD was diagnosed in n = 50 patients of the German cohort (29.6%) and in n = 29 patients (72.5%) of the Italian cohort. In all three cohorts, miR-122 was positively correlated with ALT and AST as well as with CK18 concentrations. MiR-122 levels were higher in children with NAFLD compared with healthy controls.

CONCLUSIONS

MiR-122 levels in pre-pubertal obese children could be a potential biomarker for paediatric NAFLD.

Elevation of circulating microRNA levels in obese children compared to healthy controls

As childhood obesity increases, it is becoming important to understand the complications of obesity in children and develop novel biomarkers. Evidence indicates that microRNAs (miRNA) are dys-regulated in obesity and may serve as sensitive and specific circulating biomarkers. Non-alcoholic fatty liver disease (NAFLD) is a complication of obesity that ultimately requires a liver biopsy to determine disease severity. While studies have been conducted in adults, no study to date has examined circulating miRNAs in children with obesity and NAFLD. The goal of this study was to evaluate a panel of selected circulating miRNAs in obese children compared to healthy controls. We present here an analysis of a pre-selected panel of 20 candidate miRNAs in obese children compared to healthy controls. The miRNAs were chosen based on having been previously reported to be involved in NAFLD. We found that 16 out of 20 miRNAs tested were elevated at least twofold in children with obesity compared to controls. miR-122 and miR-199a showed the greatest increase in children with obesity versus controls. Both also had a high area under the curve when receiver-operator curves were plotted. Several circulating miRNAs correlated with body mass index (BMI) or serum transaminases. This study provides initial evidence that circulating miRNAs can be measured in the paediatric population and provides several diagnostic candidates increased in children with obesity that may be relevant to NAFLD.

Effects of a sodium-glucose cotransporter 2 inhibitor in nonalcoholic fatty liver disease complicated by diabetes mellitus: Preliminary prospective study based on serial liver biopsies

A prospective study based on serial liver biopsies was performed to investigate the efficacy of sodium‐glucose cotransporter 2 inhibitor for nonalcoholic fatty liver disease complicated with type 2 diabetes mellitus. Conclusion: Treatment for 24 weeks resulted in improvement in histopathologic features in all 5 patients. (Hepatology Communications 2017;1:46–52)

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.

MicroRNAs as biomarkers and regulators of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a complicated disease affected by the interaction of environmental and genetic factors; however, the precise pathogenesis of the disease has not been fully determined. There is a need to better understand the pathogenesis of NAFLD and to identify non-invasive diagnostic modalities. Recent advances in systematic biology and epigenetics have improved our understanding of the genotype-phenotype relationships in NAFLD. MicroRNAs (miRNAs) are important regulators of a wide range of biological processes. MiRNAs are extremely stable and protect from RNAase-mediated degradation in body fluids, making them attractive candidate biomarkers for the early detection of the disease and the monitoring of disease progression. In this review, we summarized the current knowledge on miRNAs as potential biomarkers of NAFLD at different stages and for the prognosis of advanced diseases. Furthermore, we discussed the implications of miRNAs that functioning in lipid metabolism and hepatic steatosis as well as in hepatic inflammation and fibrosis with regard to the pathogenesis of NAFLD.