Identification of 8-miRNAs as biomarkers for nonalcoholic fatty liver disease

Significance of MiRNA-34a and MiRNA-192 as a risk factor for nonalcoholic fatty liver disease

BACKGROUND AND AIMS

NAFLD is one of the fast-growing health problems that affects up to 25% of people worldwide. Numerous miRNAs have been clarified as important regulators of liver pathophysiology, including NAFLD. Thus, we investigated the expression of the MiRNA-34a and MiRNA-192 as diagnostic markers for NAFLD.

PATIENTS AND METHODS

Blood samples were collected from NAFLD cases and healthy controls. The expression profile of both studied miRNAs was detected via real-time PCR analysis.

RESULTS

The present study showed that both studied miRNAs were upregulated in NAFLD patients compared to controls. Interestingly, miRNA-34a and MiRNA-192 are upregulated in NAFLD patients with early fibrosis compared to controls [with a fold change of 4.02 ± 11.49 (P = 0.05) and 18.43 ± 47.8 (P = 0.017), respectively]. However, miRNA-34a is downregulated in NAFLD patients with advanced fibrosis compared to controls, with fold expression of 0.65 ± 1.17 (P = 0.831). The area under the receiver operating characteristics (AUROC) for miRNA-34a and miRNA-192 were 0.790 and 0.643, respectively; furthermore, the sensitivities and specificities were 76.7%, 100% for miRNA-34a and 63.3%, and 93.3% for miRNA-192 (P < 0.05). Additionally, MiRNA34a was positively correlated with hypertension and fasting blood sugar, and it also was negatively correlated with hemoglobin level and total leucocyte count (P < 0.05).

CONCLUSION

The results obtained indicated that both studied miRNAs could potentially be used as diagnostic biomarkers for the early stage of liver fibrosis in NAFLD cases. Also, miRNA-34a was positively correlated with metabolic disorders associated with NAFLD such as hypertension and diabetes. However, their expression showed no association with advanced fibrosis. Thus, larger cohorts are necessitated to certify the utility of serum MiRNA-34a and MiRNA-192 in monitoring the deterioration of NAFLD.

Exploring the Regulatory Role of ncRNA in NAFLD: A Particular Focus on PPARs

Liver diseases are responsible for global mortality and morbidity and are a significant cause of death worldwide. Consequently, the advancement of new liver disease targets is of great interest. Non-coding RNA (ncRNA), such as microRNA (miRNA) and long ncRNA (lncRNA), has been proven to play a significant role in the pathogenesis of virtually all acute and chronic liver disorders. Recent studies demonstrated the medical applications of miRNA in various phases of hepatic pathology. PPARs play a major role in regulating many signaling pathways involved in various metabolic disorders. Non-alcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease in the world, encompassing a spectrum spanning from mild steatosis to severe non-alcoholic steatohepatitis (NASH). PPARs were found to be one of the major regulators in the progression of NAFLD. There is no recognized treatment for NAFLD, even though numerous clinical trials are now underway. NAFLD is a major risk factor for developing hepatocellular carcinoma (HCC), and its frequency increases as obesity and diabetes become more prevalent. Reprogramming anti-diabetic and anti-obesity drugs is an effective therapy option for NAFLD and NASH. Several studies have also focused on the role of ncRNAs in the pathophysiology of NAFLD. The regulatory effects of these ncRNAs make them a primary target for treatments and as early biomarkers. In this study, the main focus will be to understand the regulation of PPARs through ncRNAs and their role in NAFLD.

Activation of PGC-1α via isoliquiritigenin-induced downregulation of miR-138-5p alleviates nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), a metabolic disease, has received wide attention worldwide. However, there is no approved effective drug for NAFLD treatment. In the study, H&E and Oil Red O staining were employed to detect liver histopathological changes and the accumulation of lipid droplets. Quantitative real-time PCR, Western blot, bioinformatics, luciferase assay, immunofluorescence staining, reactive oxygen species (ROS), and siRNA were used to further elucidate the mechanism of isoliquiritigenin (ISL) against NAFLD. The results showed that ISL significantly reduced the liver-to-body weight ratios and biochemical index. And the staining results showed that ISL remarkedly ameliorated liver histopathological changes of NAFLD. Furthermore, ISL significantly increased the levels of PPARα, CPT1α, and ACADS, which were involved in lipid metabolism, and inhibited the ROS, TNF-α, IL-1β, and IL-6 expression by activating PGC-1α. Bioinformatics and luciferase assay analysis confirmed that miR-138-5p might bind to PGC-1α mRNA in NAFLD. Importantly, the expression of miR-138-5p was increased in the NAFLD, which was significantly decreased by ISL. In addition, the miR-138-5p inhibitor also promoted lipid metabolism and inhibited inflammatory response in NAFLD via PGC-1α activation. The above results demonstrate that ISL alleviates NAFLD through modulating miR-138-5p/PGC-1α-mediated lipid metabolism and inflammatory reaction in vivo and in vitro.

Efficacy of serum miRNA test as a non-invasive method to diagnose nonalcoholic steatohepatitis: a systematic review and meta-analysis

Background

Nonalcoholic steatohepatitis (NASH) is a key turning point during the progression of nonalcoholic fatty liver disease (NAFLD). Recent studies have shown that serum miRNA tests may be effective in the diagnosis of NAFLD. We conducted a meta-analysis to assess the evidence for the diagnostic efficacy of serum miRNAs in patients with NAFLD and its subtype, NASH, in particular.

Methods

After a systematic review, sensitivity, specificity, and area under the receiver operating characteristics curve (AUROC) were pooled to determine the efficacy of serum miRNA test for the diagnosis of NAFLD and NASH. Clinical utility was evaluated by Fagan’s nomogram and likelihood ratio scattergram. Heterogeneity was evaluated by subgroup analysis and meta-regression. Publication bias was detected by Deeks’ funnel plot.

Results

We included 27 trials containing 1775 NAFLD patients (including simple steatosis and NASH) and 586 NASH patients. For NAFLD vs NASH, the pooled sensitivity, specificity, and AUROC were (0.71 vs. 0.74), (0.76 vs. 0.85) and (0.80 vs. 0.86), respectively. Serum miRNA had high accuracy for distinguishing NASH from simple steatosis, with an AUROC of 0.91. Among the most commonly studied serum miRNAs, miRNA-34a showed moderate diagnostic accuracy for NAFLD and the lowest heterogeneity (sensitivity I² = 5.73%, specificity I² = 33.16%, AUROC = 0.85). According to subgroup analysis and meta-regression, a lower BMI (< 30 kg/m²) might be a crucial source of heterogeneity.

Conclusions

As a novel non-invasive method, serum miRNA test exhibited robust diagnostic efficacy for NASH. Among these well-studied miRNAs, miRNA-34a was more available for diagnosis. Diagnosis of NAFLD by serum miRNA is more likely to be accurate in patients with BMI ≥ 30 kg/m².

miRNA Dysregulation in the Development of Non-Alcoholic Fatty Liver Disease and the Related Disorders Type 2 Diabetes Mellitus and Cardiovascular Disease

According to the World Health Organization, the continuing surge in obesity pandemic creates a substantial increase in incidences of metabolic disorders, such as non-alcoholic fatty liver disease (NAFLD), type 2 diabetes mellitus, and cardiovascular disease. MicroRNAs (miRNAs) belong to an evolutionarily conserved class of short (20-22 nucleotides in length) and single-stranded non-coding RNAs. In mammals, miRNAs function as critical post-transcriptional negative regulators involved not only in many biological processes but also in the development of many diseases such as NAFLD and comorbidities. More recently, it has been described that cells can secrete miRNAs in extracellular vesicles, transported by body fluids, and uptaken by other tissues regulating gene expression. Therefore, this could be a mechanism of signaling involved not only in physiological pathways but also in the development of diseases. The association of some miRNA expression profiles with certain disorders has made them very interesting molecules for diagnosis, prognosis, and disease management. The finding of specific miRNA signatures to diagnose NAFLD and related diseases could anticipate the risk of development of related complications and, actually, it is the driving force of present health strategies worldwide. In this review, we have included latest advances in knowledge about the miRNAs involved in the development of NAFLD and related diseases and examined how this knowledge could be used to identify new non-invasive biomarkers and new pharmacological interventions.