Exosomal and non-exosomal miRNA expression levels in patients with HCV-related cirrhosis and liver cancer

Exosomes, and the potential for exosome-based interventions against COVID-19

Since late 2019, the world has been devastated by the coronavirus disease 2019 (COVID-19) induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with more than 760 million people affected and ∼seven million deaths reported. Although effective treatments for COVID-19 are currently limited, there has been a strong focus on developing new therapeutic approaches to address the morbidity and mortality linked to this disease. An approach that is currently being investigated is the use of exosome-based therapies. Exosomes are small, extracellular vesicles that play a role in many clinical diseases, including viral infections, infected cells release exosomes that can transmit viral components, such as miRNAs and proteins, and can also include receptors for viruses that facilitate viral entry into recipient cells. SARS-CoV-2 has the ability to impact the formation, secretion, and release of exosomes, thereby potentially facilitating or intensifying the transmission of the virus among cells, tissues and individuals. Therefore, designing synthetic exosomes that carry immunomodulatory cargo and antiviral compounds are proposed to be a promising strategy for the treatment of COVID-19 and other viral diseases. Moreover, exosomes generated from mesenchymal stem cells (MSC) might be employed as cell-free therapeutic agents, as MSC-derived exosomes can diminish the cytokine storm and reverse the suppression of host anti-viral defences associated with COVID-19, and boost the repair of lung damage linked to mitochondrial activity. The present article discusses the significance and roles of exosomes in COVID-19, and explores potential future applications of exosomes in combating this disease. Despite the challenges posed by COVID-19, exosome-based therapies could represent a promising avenue for improving patient outcomes and reducing the impact of this disease.

Potential of miRNAs in Plasma Extracellular Vesicle for the Stratification of Prostate Cancer in a South African Population

Prostate cancer (PCa) is the most common cause of cancer death among African men. The analysis of microRNAs (miRNAs) in plasma extracellular vesicles (EVs) can be utilized as a non-invasive tool for the diagnosis of PCa. In this study, we used small RNA sequencing to profile miRNAs cargo in plasma EVs from South African PCa patients. We evaluated the differential expression of miRNAs between low and high Gleason scores in the plasma EVs of South African patients and in the prostatic tissue from data available in the Cancer Genome Atlas (TCGA) Data Portal. We identified 7 miRNAs differently expressed in both EVs and prostatic tissues. We evaluated their expression using qPCR in a larger cohort of 10 patients with benign prostatic hyperplasia (BPH) and 24 patients with PCa. Here, we reported that the ratio between two of these miRNAs (i.e., miR-194-5p/miR-16-5p) showed a higher concentration in PCa compared to BPH and in metastatic PCa compared to localized PCa. We explored for the first time the profiling of miRNAs cargo in plasma EVs as a tool for the identification of putative markers in the South African population. Our finding indicated the ratio miR-194-5p/miR-16-5p as a non-invasive marker for the evaluation of PCa aggressiveness in this population.

Circulating Biomarkers for Cancer Detection: Could Salivary microRNAs Be an Opportunity for Ovarian Cancer Diagnostics?

MicroRNAs (miRNAs) are small non-coding RNAs with the crucial regulatory functions of gene expression at post-transcriptional level, detectable in cell and tissue extracts, and body fluids. For their stability in body fluids and accessibility to sampling, circulating miRNAs and changes of their concentration may represent suitable disease biomarkers, with diagnostic and prognostic relevance. A solid literature now describes the profiling of circulating miRNA signatures for several tumor types. Among body fluids, saliva accurately reflects systemic pathophysiological conditions, representing a promising diagnostic resource for the future of low-cost screening procedures for systemic diseases, including cancer. Here, we provide a review of literature about miRNAs as potential disease biomarkers with regard to ovarian cancer (OC), with an excursus about liquid biopsies, and saliva in particular. We also report on salivary miRNAs as biomarkers in oncological conditions other than OC, as well as on OC biomarkers other than miRNAs. While the clinical need for an effective tool for OC screening remains unmet, it would be advisable to combine within a single diagnostic platform, the tools for detecting patterns of both protein and miRNA biomarkers to provide the screening robustness that single molecular species separately were not able to provide so far.

MicroRNAs: Small Molecules with Significant Functions, Particularly in the Context of Viral Hepatitis B and C Infection

A MicroRNA (miRNA) is defined as a small molecule of non-coding RNA (ncRNA). Its molecular size is about 20 nucleotides (nt), and it acts on gene expression's regulation at the post-transcription level through binding to the 3'untranslated regions (UTR), coding sequences, or 5'UTR of the target messenger RNAs (mRNAs), which leads to the suppression or degradation of the mRNA. In recent years, a huge evolution has identified the origin and function of miRNAs, focusing on their important effects in research and clinical applications. For example, microRNAs are key players in HCV infection and have important host cellular factors required for HCV replication and cell growth. Altered expression of miRNAs affects the pathogenicity associated with HCV infection through regulating different signaling pathways that control HCV/immunity interactions, proliferation, and cell death. On the other hand, circulating miRNAs can be used as novel biomarkers and diagnostic tools for HCV pathogenesis and early therapeutic response. Moreover, microRNAs (miRNA) have been involved in hepatitis B virus (HBV) gene expression and advanced antiviral discovery. They regulate HBV/HCV replication and pathogenesis with different pathways involving facilitation, inhibition, activation of the immune system (innate and adaptive), and epigenetic modifications. In this short review, we will discuss how microRNAs can be used as prognostic, diagnostic, and therapeutic tools, especially for chronic hepatitis viruses (HBV and HCV), as well as how they could be used as new biomarkers during infection and advanced treatment.

Dual roles and potential applications of exosomes in HCV infections

The hepatitis C virus (HCV) causes severe liver diseases, including hepatitis, liver cirrhosis, and hepatocellular carcinoma, which have high morbidity and mortality. Antibody targeting receptor-mediated HCV infections have limited therapeutic benefits, suggesting that the transmission of HCV infections is possibly mediated via receptor-independent mechanisms. Exosomes are membrane-enclosed vesicles with a diameter of 30-200 nm, which originate from the fusion of endosomal multivesicular bodies with the plasma membrane. Accumulating evidence suggests that exosomes have a pivotal role in HCV infections. Exosomes can transfer viral and cellular bioactive substances, including nucleic acids and proteins, to uninfected cells, thus spreading the infection by masking these materials from immunological recognition. In addition, exosomes originating from some cells can deliver antiviral molecules or prompt the immune response to inhibit HCV infection. Exosomes can be used for the diagnosis of HCV-related diseases, and are being presently evaluated as therapeutic tools for anti-HCV drug delivery. This review summarizes the current knowledge on the dual roles and potential clinical applications of exosomes in HCV infections.

Diagnostic value of exosomes in patients with liver cancer: a systematic review

BACKGROUND

Liver cancer is a disease with high morbidity and mortality. More and more studies have shown that exosomes can be used as biomarkers for the diagnosis of liver cancer, but their diagnostic accuracy is still unclear. Therefore, this meta-analysis summarizes various studies on the diagnostic value of exosomes for liver cancer.

METHODS

A comprehensive search was carried out based on the set search terms in PubMed, Web of Science and Wiley until April 1, 2022. All statistical analyses were performed by STATA 17 statistical software and Review Manager 5.4. Quality Assessment for Studies of Diagnostic Accuracy 2 tool was applied to evaluate the quality of included articles. Random effects model was used to calculate various diagnostic indicators.

RESULTS

A total of 47 studies were included in this meta-analysis. The number of participants was 3196. The combined sensitivity, specificity and the area under the curve with 95% confidence intervals (95% CI) were, respectively 0.80 (0.75-0.84), 0.83 (0.79-0.87), 0.89 (0.85-0.91).

CONCLUSIONS

This meta-analysis shows that exosomes have good diagnostic accuracy for liver cancer and can be used as an effective biomarker for the diagnosis of liver cancer.

Upregulated miRNAs on the TP53 and RB1 Binding Seedless Regions in High-Risk HPV-Associated Penile Cancer

Cancer development by the human papillomavirus (HPV) infection can occur through the canonical HPV/p53/RB1 pathway mediated by the E2/E6/E7 viral oncoproteins. During the transformation process, HPV inserts its genetic material into host Integration Sites (IS), affecting coding genes and miRNAs. In penile cancer (PeCa) there is limited data on the miRNAs that regulate mRNA targets associated with HPV, such as the TP53 and RB1 genes. Considering the high frequency of HPV infection in PeCa patients in Northeast Brazil, global miRNA expression profiling was performed in high-risk HPV-associated PeCa that presented with TP53 and RB1 mRNA downregulated expression. The miRNA expression profile of 22 PeCa tissue samples and five non-tumor penile tissues showed 507 differentially expressed miRNAs: 494 downregulated and 13 upregulated (let-7a-5p, miR-130a-3p, miR-142-3p, miR-15b-5p miR-16-5p, miR-200c-3p, miR-205-5p, miR-21-5p, miR-223-3p, miR-22-3p, miR-25-3p, miR-31-5p and miR-93-5p), of which 11 were identified to be in HPV16-IS and targeting TP53 and RB1 genes. One hundred and thirty-one and 490 miRNA binding sites were observed for TP53 and RB1, respectively, most of which were in seedless regions. These findings suggest that up-regulation of miRNA expression can directly repress TP53 and RB1 expression by their binding sites in the non-canonical seedless regions.