Circulating MicroRNAs in Gastrointestinal Cancer

Differential expression of serum miR-486 and miR-25 in ulcerative colitis and Crohn's disease: Correlations with disease activity, extent, and location

Novel reliable biomarkers of inflammatory bowel disease (IBD) are clinically imperative due to potential limitations of endoscopic techniques. MicroRNAs (miRNAs) have emerged as non-invasive biomarkers of IBD; however, the full disease-specific miRNAs signature for IBD subtypes remains elusive. We evaluated the diagnostic role of circulating miR-486 and miR-25 in IBD patients and their potential ability to discriminate IBD subtypes; ulcerative colitis (UC) and Crohn's disease (CD). Sixty UC patients, 60 CD patients, and 60 healthy controls were recruited. Serum miRNA expression was determined using RT-qPCR. Bioinformatics was employed for target gene and protein-protein interaction (PPI) network analyses. Serum miR-486 was upregulated in CD patients, but didn't change in UC patients compared to controls. Conversely, serum miR-25 was decreased in both CD and UC patients compared to controls. Only miR-486 was differentially expressed between UC and CD patients. Receiver-operating characteristic analysis revealed that serum miR-486 was superior in CD diagnosis (AUC=0.945) and significantly distinguished CD and UC patients, whereas miR-25 showed discriminative potential for both UC and CD from controls. In the multivariate logistic analysis only miR-486 was associated with the risk of CD diagnosis. Serum miR-486 was correlated with CD activity index and location of disease in CD patients, whereas miR-25 was correlated with the type/extent of UC. PPI network analysis revealed common target genes and signaling pathways for both miRNAs. Conclusively, serum miR-486 and miR-25 might serve as new biomarkers of IBD, with serum miR-486 could be employed in risk stratification of IBD subtypes and has the ground for clinical utility in CD diagnosis, whereas miR-25 has potential for UC and CD diagnosis.

The Role of microRNAs in Epigenetic Regulation of Signaling Pathways in Neurological Pathologies

In recent times, there has been a significant increase in researchers' interest in the functions of microRNAs and the role of these molecules in the pathogenesis of many multifactorial diseases. This is related to the diagnostic and prognostic potential of microRNA expression levels as well as the prospects of using it in personalized targeted therapy. This review of the literature analyzes existing scientific data on the involvement of microRNAs in the molecular and cellular mechanisms underlying the development of pathologies such as Alzheimer's disease, cerebral ischemia and reperfusion injury, and dysfunction of the blood-brain barrier.

Epigenetic regulation in colorectal cancer: The susceptibility of microRNAs 145, 143 and 133b to DNA demethylation and histone deacetylase inhibitors

Globally, colorectal cancer (CRC) is a major health concern. Despite improvements in CRC treatment, mortality rates remain high. Genetic instability and epigenetic dysregulation of gene expression are instigators of CRC development that result in genotypic differences, leading to often variable and unpredictable treatment responses. Three miRNAs, miR-143, -145 and -133b, are most commonly downregulated in CRC and are proposed here as potential tumour suppressors. Although the downregulation of these miRNAs in CRC is largely unexplained, epigenetic silencing has been postulated to be a causative regulatory mechanism. Potential epigenetic modulation of miRNA expression, by means of histone acetylation and DNA methylation, was assessed in this study by treating early (SW1116) and late stage (DLD1) CRC cells with the DNA demethylating agent 5-aza-2'-deoxycytidine (5-Aza-2'C) and the histone deacetylase (HDAC) inhibitor Trichostatin A (TSA), respectively. Subsequent quantification of miRNA expression revealed that while all the selected miRNAs were susceptible to DNA demethylation in early- and late-stage CRC cells, susceptibility to DNA demethylation was significantly pronounced in late-stage DLD1 cells. Conversely, although histone acetylation moderately affected miRNA expression in early-stage CRC, it had a marginal effect on the expression of miRNAs in late-stage CRC cells. Overall, this study provides further understanding of the contribution of epigenetics to the regulation of putative tumour suppressor miRNAs in CRC.

Role of salivary miRNAs in the diagnosis of gastrointestinal disorders: a mini-review of available evidence

MiRNAs are short, non-coding RNA molecules, which are involved in the regulation of gene expression and which play an important role in various biological processes, including inflammation and cell cycle regulation. The possibility of detecting their extracellular expression, within body fluids, represented the main background for their potential use as non-invasive biomarkers of various diseases. Salivary miRNAs particularly gained interest recently due to the facile collection of stimulated/unstimulated saliva and their stability among healthy subjects. Furthermore, miRNAs seem to represent biomarker candidates of gastrointestinal disorders, with miRNA-based therapeutics showing great potential in those conditions. This review aimed to highlight available evidence on the role of salivary miRNAs in different gastrointestinal conditions. Most salivary-based miRNA studies available in the literature that focused on pathologies of the gastrointestinal tract have so far been conducted on pancreatic cancer patients and delivered reliable results. A few studies also showed the diagnostic utility of salivary miRNAs in conditions such as esophagitis, esophageal cancer, colorectal cancer, or inflammatory bowel disease. Moreover, several authors showed that salivary miRNAs may confidently be used as biomarkers of gastric cancer, but the use of salivary miRNA candidates in gastric inflammation and pre-malignant lesions, essential stages of Correa's cascade, is still put into question. On the other hand, besides miRNAs, other salivary omics have shown biomarker potential in gastro-intestinal conditions. The limited available data suggest that salivary miRNAs may represent reliable biomarker candidates for gastrointestinal conditions. However, their diagnostic potential requires validation through future research, performed on larger cohorts.

Circulating microRNAs as diagnostic biomarkers for melanoma: a systematic review and meta-analysis

BACKGROUND

Recent studies have shown that circulating microRNAs (miRNAs) can be used as diagnostic biomarkers for melanoma. This study aimed to evaluate the diagnostic value of circulating miRNAs for melanoma.

METHODS

A comprehensive literature search was conducted and the quality of the included literature was evaluated using QUADAS-2 (Quality Assessment for diagnostic accuracy studies), and the diagnostic accuracy was assessed by pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC). We used Deeks' funnel plot to evaluate publication bias.

RESULTS

The meta-analysis included 10 articles covering 16 studies, and the results showed that circulating miRNAs provide high diagnostic accuracy for melanoma. The overall pooled sensitivity was 0.87 (95% CI: 0.82-0.91), specificity was 0.81 (95% CI: 0.77-0.85), PLR was 4.6 (95% CI: 3.7-5.8), NLR was 0.16 (95% CI: 0.11-0.23), DOR was 29 (95% CI: 18-49), and AUC was 0.90 (95% CI: 0.87-0.92), respectively. Subgroup analysis showed better diagnostic value in miRNA clusters, European population, plasma miRNAs, and upregulated miRNAs compared to other subgroups.

CONCLUSIONS

The results indicated that circulating microRNAs can be used as a non-invasive biomarker for the diagnosis of melanoma.

Milk exosomes-mediated miR-31-5p delivery accelerates diabetic wound healing through promoting angiogenesis

The refractory diabetic wound has remained a worldwide challenge as one of the major health problems. The impaired angiogenesis phase during diabetic wound healing partly contributes to the pathological process. MicroRNA (miRNA) is an essential regulator of gene expression in crucial biological processes and is a promising nucleic acid drug in therapeutic fields of the diabetic wound. However, miRNA therapies have limitations due to lacking an effective delivery system. In the present study, we found a significant reduction of miR-31-5p expression in the full-thickness wounds of diabetic mice compared to normal mice. Further, miR-31-5p has been proven to promote the proliferation, migration, and angiogenesis of endothelial cells. Thus, we conceived the idea of exogenously supplementing miR-31-5p mimics to treat the diabetic wound. We used milk-derived exosomes as a novel system for miR-31-5p delivery and successfully encapsulated miR-31-5p mimics into milk exosomes through electroporation. Then, we proved that the miR-31-5p loaded in exosomes achieved higher cell uptake and was able to resist degradation. Moreover, our miRNA-exosomal formulation demonstrated dramatically improved endothelial cell functions in vitro, together with the promotion of angiogenesis and enhanced diabetic wound healing in vivo. Collectively, our data showed the feasibility of milk exosomes as a scalable, biocompatible, and cost-effective delivery system to enhance the bioavailability and efficacy of miRNAs.