Epigenetic investigation into circulating microRNA 197-3p in sera from patients affected by malignant pleural mesothelioma and workers ex-exposed to asbestos.

The epigenetic role of microRNAs is established at both physiological and pathological levels. Dysregulated miRNAs and their targets appear to be a promising approach for innovative anticancer therapies. In our previous study, circulating miR-197-3p tested dysregulated in workers ex-exposed to asbestos (WEA). Herein, an epigenetic investigation on this circulating miRNA was carried out in sera from malignant pleural mesothelioma (MPM) patients. MiR-197-3p was quantified in MPM (n = 75) sera and comparatively analyzed to WEA (n = 75) and healthy subject (n = 75) sera, using ddPCR and RT-qPCR techniques. Clinicopathological characteristics, occupational, non-occupational information and overall survival (OS) were evaluated in correlation studies. MiR-197-3p levels, analyzed by ddPCR, were significantly higher in MPM than in WEA cohort, with a mean copies/µl of 981.7 and 525.01, respectively. Consistently, RT-qPCR showed higher miR-197-3p levels in sera from MPM with a mean copies/µl of 603.7, compared to WEA with 336.1 copies/µl. OS data were significantly associated with histologic subtype and pleurectomy. Circulating miR-197-3p is proposed as a new potential biomarker for an early diagnosis of the MPM onset. Indeed, miR-197-3p epigenetic investigations along with chest X-ray, computed tomography scan and spirometry could provide relevant information useful to reach an early and effective diagnosis for MPM.

Circulating microRNA-197-3p as a potential biomarker for asbestos exposure.

Asbestos is considered the main cause of diseases in workers exposed to this mineral in the workplace as well as an environmental pollutant. The association between asbestos and the onset of different diseases has been reported, but asbestos exposure specific biomarkers are not known. MicroRNAs (miRNAs) are small, single-strand, non-coding RNAs, with potential value as diagnostic, prognostic, and predictive markers in liquid biopsies. Sera collected from workers ex-exposed to asbestos (WEA) fibers were compared with sera from healthy subjects (HS) of similar age, as liquid biopsies. The expression of the circulating miRNA 197-3p was investigated employing two different highly analytical PCR methods, i.e. RT-qPCR and ddPCR. MiR-197-3p levels were tested in sera from WEA compared to HS. MiR-197-3p tested dysregulated in sera from WEA (n = 75) compared to HS (n = 62). Indeed, miR-197-3p was found to be 2.6 times down-regulated in WEA vs. HS (p = 0.0001***). In addition, an inverse correlation was detected between miR-197-3p expression level and cumulative asbestos exposure, being this miRNA down-regulated 2.1 times in WEA, with high cumulative asbestos exposure, compared to WEA with low exposure (p = 0.0303*). Circulating miR-197-3p, found to be down regulated in sera from WEA, is proposed as a new potential biomarker of asbestos exposure.

The role of microRNAs in the osteogenic and chondrogenic differentiation of mesenchymal stem cells and bone pathologies.

Mesenchymal stem cells (MSCs) have been identified in many adult tissues. MSCs can regenerate through cell division or differentiate into adipocytes, osteoblasts and chondrocytes. As a result, MSCs have become an important source of cells in tissue engineering and regenerative medicine for bone tissue and cartilage. Several epigenetic factors are believed to play a role in MSCs differentiation. Among these, microRNA (miRNA) regulation is involved in the fine modulation of gene expression during osteogenic/chondrogenic differentiation. It has been reported that miRNAs are involved in bone homeostasis by modulating osteoblast gene expression. In addition, countless evidence has demonstrated that miRNAs dysregulation is involved in the development of osteoporosis and bone fractures. The deregulation of miRNAs expression has also been associated with several malignancies including bone cancer. In this context, bone-associated circulating miRNAs may be useful biomarkers for determining the predisposition, onset and development of osteoporosis, as well as in clinical applications to improve the diagnosis, follow-up and treatment of cancer and metastases. Overall, this review will provide an overview of how miRNAs activities participate in osteogenic/chondrogenic differentiation, while addressing the role of miRNA regulatory effects on target genes. Finally, the role of miRNAs in pathologies and therapies will be presented.

MicroRNAs Modulate Signaling Pathways in Osteogenic Differentiation of Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) have been identified in many adult tissues and they have been closely studied in recent years, especially in view of their potential use for treating diseases and damaged tissues and organs. MSCs are capable of self-replication and differentiation into osteoblasts and are considered an important source of cells in tissue engineering for bone regeneration. Several epigenetic factors are believed to play a role in the osteogenic differentiation of MSCs, including microRNAs (miRNAs). MiRNAs are small, single-stranded, non-coding RNAs of approximately 22 nucleotides that are able to regulate cell proliferation, differentiation and apoptosis by binding the 3' untranslated region (3'-UTR) of target mRNAs, which can be subsequently degraded or translationally silenced. MiRNAs control gene expression in osteogenic differentiation by regulating two crucial signaling cascades in osteogenesis: the transforming growth factor-beta (TGF-ß)/bone morphogenic protein (BMP) and the Wingless/Int-1(Wnt)/ß-catenin signaling pathways. This review provides an overview of the miRNAs involved in osteogenic differentiation and how these miRNAs could regulate the expression of target genes.

Endogenous retrovirus expression activates type-I interferon signaling in an experimental mouse model of mesothelioma development.

Early events in an experimental model of mesothelioma development include increased levels of editing in double-stranded RNA (dsRNA). We hypothesised that expression of endogenous retroviruses (ERV) contributes to dsRNA formation and type-I interferon signaling. ERV and interferon stimulated genes (ISGs) expression were significantly higher in tumor compared to non-tumor samples. 12 tumor specific ERV ("MesoERV1-12") were identified and verified by qPCR in mouse tissues. "MesoERV1-12" expression was lower in mouse embryonic fibroblasts (MEF) compared to mesothelioma cells. "MesoERV1-12" levels were significantly increased by demethylating agent 5-Aza-2'-deoxycytidine treatment and were accompanied by increased levels of dsRNA and ISGs. Basal ISGs expression was higher in mesothelioma cells compared to MEF and was significantly decreased by JAK inhibitor Ruxolitinib, by blocking Ifnar1 and by silencing Mavs. "MesoERV7" promoter was demethylated in asbestos-exposed compared to sham mice tissue as well as in mesothelioma cells and MEF upon 5-Aza-CdR treatment. These observations uncover novel aspects of asbestos-induced mesothelioma whereby ERV expression increases due to promoter demethylation and is paralleled by increased levels of dsRNA and activation of type-I IFN signaling. These features are important for early diagnosis and therapy.

Antibodies reacting to mimotopes of Simian virus 40 large T antigen, the viral oncoprotein, in sera from children.

Recent data indicate that the Simian virus 40 (SV40) infection appears to be transmitted in humans independently from early SV40-contaminated antipolio vaccines. Serum antibodies against SV40 large T antigen (Tag) were analyzed in children/adolescents and young adults. To investigate antibodies reacting to SV40 Tag antigens, serum samples ( n = 812) from children and young adults were analyzed by indirect ELISAs using specific SV40 Tag mimotopes. Mimotopes were synthetic peptides corresponding to SV40 Tag epitopes. In sera ( n = 412) from healthy children up to 17 years old, IgG antibodies against SV40 Tag mimotopes reached an overall prevalence of 15%. IgM antibodies against SV40 Tag were detected in sera of children 6-8 months old confirming and extending the knowledge that SV40 seroconversion occurs early in life. In children/adolescents affected by different diseases ( n = 180) SV40 Tag had a prevalence of 18%, being the difference no significant compared to healthy subjects ( n = 220; 16%) of the same age. Our immunological data indicate that SV40 circulates in children and young adults, both in healthy conditions and affected by distinct diseases. The IgM detection in sera from healthy children suggests that the SV40 infection/seroconversion occurs early in life (>6 months). Our immunological data support the hypothesis that SV40, or a closely related still unknown polyomavirus, infects humans. The SV40 seroprevalence is lower than common polyomaviruses, such as BKPyV and JCPyV, and other new human polyomaviruses. In addition, our immunological surveillance indicates a lack of association between different diseases, considered herein, and SV40.