Prediction of Age-Related MicroRNA Signature in Mesenchymal Stem Cells by using Computational Methods.

BACKGROUND: Aging is a phenomenon which occurs over time and leads to the decay of living organisms. During the progression of aging, some age-associated diseases including cardiovascular disease, cancers, and neurological, mental, and physical disorders could develop. Genetic and epigenetic factors like microRNAs, as one of the post-transcriptional regulators of genes, play important roles in senescence. The self-renewal and differentiation capacity of mesenchymal stem cells makes them good candidates for regenerative medicine. OBJECTIVE: The objective of this study is to evaluate senescence-related miRNAs in human MSCs using bioinformatics analysis. METHODS: In this study, the Gene Expression Omnibus (GEO) database was used to investigate the senescence-related genome profile. Then, down-regulated genes were selected for further bioinformatics analysis with the assumption that their decreased expression is associated with an increased aging process. Considering that miRNAs can interfere in gene expression, miRNAs complementary to these genes were identified using bioinformatics software. RESULTS: Through bioinformatics analysis, we predicted hsa-miR-590-3p, hsa-miR-10b-3p, hsamiR- 548 family, hsa-miR-144-3p, and hsa-miR-30b-5p which involve in cellular senescence and the aging of human MSCs. CONCLUSION: miRNA mimics or anti-miRNA agents have the potential to be used as anti-aging tools for MSCs.

In vitro naive CD4+ T cell differentiation upon treatment with miR-29b-loaded exosomes from mesenchymal stem cells.

BACKGROUND: Gene regulation by microRNA (miRNA) is central in T lymphocytes differentiation processes. Here, we investigate miRNA-29b (miR-29b) roles in the reprogramming of T cell differentiation, which can be a promising therapeutic avenue for various types of inflammatory disorders such as rheumatoid arthritis and multiple sclerosis. METHODS AND RESULTS: Adipose Mesenchymal Stem Cell-derived exosomes (AMSC-Exo) enriched with miR-29b were delivered into naive CD4+ T (nCD4+) cells. The expression level of important transcription factors including RAR-related orphan receptor gamma (RORγt), GATA3 binding protein (GATA3), T-box transcription factor 21, and Forkhead box P3 was determined by quantitative Real-Time PCR. Moreover, flow cytometry and Enzyme-linked Immunosorbent Assay were respectively used to measure the frequency of T regulatory cells and the levels of cytokines production (Interleukin 17, Interleukin 4, Interferon-gamma, and transforming growth factor beta. This study indicates that the transfection of miR-29b mimics into T lymphocytes through AMSC-Exo can alter the CD4+ T cells' differentiation into other types of T cells. CONCLUSIONS: In conclusion, AMSC-Exo-based delivery of miR-29b can be considered as a new fascinating avenue for T cell differentiation inhibition and the future treatment of several inflammatory disorders.

Dysregulation of miRNA expression in patients with chronic myelogenous leukemia at diagnosis: a systematic review.

Aim: The present systematic review aimed to explore miRNAs as a potential biomarker for early diagnosis of chronic myeloid leukemia (CML). Materials & methods: A systematic search was conducted in three electronic databases, including Web of Science, Scopus and PubMed, to obtain relevant articles investigating the alteration of miRNA expression in patients with CML. Results: The authors found miRNAs whose expression changes are effective in the induction of CML disease. Among them, miR-21 and miR-155 were identified as the most common miRNAs with increased expression and miR-150 and miR-146 as the most common miRNAs with decreased expression. Conclusion: miRNAs can be used as an indicator for the early detection and treatment of CML phase.

Transient induction of Cdk9 in the early stage of differentiation is critical for myogenesis.

Cdk9 is a serine-threonine protein kinase that has been recognized as a regulator of cardiac differentiation. Recently, we have reported that transient induction of Cdk9 using noncoding RNA targeting Cdk9 sequences results in efficient cardiac differentiation. Concerning Cdk9 regulatory roles, here, we proposed whether constant overexpression of Cdk9 might influence the differentiation of myoblast C2C12 cells into myotubes. We overexpressed Cdk9 in mouse myoblast C2C12 cells to investigate its regulatory roles on myogenic differentiation. Upon Cdk9 overexpression, the expression level of myogenic regulatory factors was determined. Moreover, the expression profile of three important myomiRs consist of miR 1, 133 and 206 was examined during the differentiation process. Although Cdk9 expression is necessary for inducing differentiation in the early stage of myogenesis, continuous Cdk9 expression inhibits differentiation by modulating myomiRs and myogenic gene expression. Our results indicate that the transient induction of Cdk9 in the early stage of differentiation is critical for myogenesis.

Rn7SK small nuclear RNA is involved in cellular senescence.

Rn7SK is a conserved small nuclear noncoding RNA which its function in aging has not been studied. Recently, we have demonstrated that Rn7SK overexpression reduces cell viability and is significantly downregulated in stem cells, human tumor tissues, and cell lines. In this study, we analyzed the role of Rn7SK on senescence in adipose tissue-derived mesenchymal stem cells (AD-MSCs). For this purpose, Rn7SK expression was downregulated and upregulated via transfection and transduction, respectively, in AD-MSCs and subsequently, various distinct characteristics of senescence including cell viability, proliferation, colony formation, senescence-associated ß galactosidase activity, and differentiation potency was analyzed. Our results demonstrated the transient knockdown of Rn7SK in MSCs leads to delayed senescence, while its overexpressions shows opposite effects. When osteogenic differentiation was started, however, they exhibited a greater differentiation potential than the original MSCs, suggesting a potential tool for stem cell-based regenerative medicine.