Human Umbilical Cord Mesenchymal Stem Cells-Derived Small Extracellular Vesicles Can Be Considered as Cell-Free Therapeutics for Angiogenesis Promotion.

OBJECTIVE: Angiogenesis has critical roles in several physiological processes. Restoring angiogenesis in some pathological conditions such as a few vascular diseases can be a therapeutic approach to controlling this issue. Mesenchymal stem cells (MSCs) secrete specific intracellular products known as extracellular vesicles (EVs) with high therapeutic potential which compared to their source cells, do not have the limitations of cell therapy. The angiogenic effect of the human umbilical cord MSCs (hUCMSCs)-derived small EVs are evaluated in the present work. Aim of this research is to show that hUCMSCs-derived small EVs cause differentiation of genes involved in angiogenesis like FGFR-1, FGF, VEGF, and VEGFR-2. MATERIALS AND METHODS: In this experimental study, MSCs were isolated from the human umbilical cord, and after confirming their identities, their secreted EVs (including exosomes) were extracted by ultracentrifugation. The isolated small EVs were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), bicinchoninic acid assay (BCA), and Western Blotting. Then, the human umbilical vein endothelial cells (HUVECs) were treated with derived small EVs for 72 hours, and the expression of the angiogenic factors including FGFR-1, FGF, VEGF, and VEGFR-2 was evaluated by quantitative real-time-polymerase chain reaction (qPCR). Angiogenesis was also evaluated via a tube formation assay. RESULTS: The results demonstrated that FGFR-1, FGF, VEGF, and VEGFR-2 could be elevated 2, 2, 3.5, and 2 times, respectively, in EVs treated HUVECs, and derivative EVs can encourage tube formation in HUVECs. CONCLUSION: These findings imply that hUCMSCs-derived small EVs are valuable resources in promoting angiogenesis and are very promising in cell-free therapy.

A critical role for miR-184 in the fate determination of oligodendrocytes.

BACKGROUND: New insights on cellular and molecular aspects of both oligodendrocyte (OL) differentiation and myelin synthesis pathways are potential avenues for developing a cell-based therapy for demyelinating disorders comprising multiple sclerosis. MicroRNAs (miRNA) have broad implications in all aspects of cell biology including OL differentiation. MiR-184 has been identified as one of the most highly enriched miRNAs in oligodendrocyte progenitor cells (OPCs). However, the exact molecular mechanism of miR-184 in OL differentiation is yet to be elucidated. METHODS AND RESULTS: Based on immunochemistry assays, qRT-PCR, and western blotting findings, we hypothesized that overexpression of miR-184 in either neural progenitor cells (NPCs) or embryonic mouse cortex stimulated the differentiation of OL lineage efficiently through regulating crucial developmental genes. Luciferase assays demonstrated that miR-184 directly represses positive regulators of neural and astrocyte differentiation, i.e., SOX1 and BCL2L1, respectively, including the negative regulator of myelination, LINGO1. Moreover, blocking the function of miR-184 reduced the number of committed cells to an OL lineage. CONCLUSIONS: Our data highlighted that miR-184 could promote OL differentiation even in the absence of exogenous growth factors and propose a novel strategy to improve the efficacy of OL differentiation, with potential applications in cell therapy for neurodegenerative diseases.

miR-455-5p downregulation promotes inflammation pathways in the relapse phase of relapsing-remitting multiple sclerosis disease.

MicroRNA-455-5p (miR-455-5p) seems to have an anti-inflammatory role in the immune system since its expression is induced by IL-10 cytokine. Multiple sclerosis (MS) is a chronic demyelinating neurodegenerative disease of the central nervous system that is caused by an autoimmune inflammatory attack against the myelin insulation of neurons. The expression level of miR-455-5p and its role in MS pathogenesis has yet to be elucidated. We found that miR-455-5p expression was highly correlated with disease severity in MS patients. miR-455-5p expression inversely correlates with its inflammatory-predicted targets (MyD88 and REL) in relapse- and remitting-phase patients. Luciferase assays confirm that MyD88 and REL are direct targets of miR-455-5p. This study represents the first report of the miR-455-5p acts as an anti-inflammatory role in MS, at least partially through targeting MyD88 and REL. This study may provide important information for the use of miR-455-5p as a novel strategy to improve the severity of disease and control inflammation and attack in MS patients.

Overexpression of miR-133 decrease primary endothelial cells proliferation and migration via FGFR1 targeting.

Angiogenesis is one of the essential hallmarks of cancer that is controlled by the balance between positive and negative regulators. FGFR1 signaling is crucial for the execution of bFGF-induced proliferation, migration, and tube formation of endothelial cells (ECs) and onset of angiogenesis on tumors. The purpose of this study is to identify whether or not miR-133 regulates FGFR1 expression and accordingly hypothesize if it plays a crucial role in modulating bFGF/FGFR1 activity in ECs and blocking tumor angiogenesis through targeting FGFR1. The influences of miR-133 overexpression on bFGF stimulated endothelial cells were assessed by cell growth curve, MTT assaying, tube formation, and migration assays. Forced expression of miR-133 caused significant reductions in bFGF-induced proliferation and migratory ability of ECs. MiR-133 Expression was negatively correlated with both mRNA and protein levels of FGFR1 in the transfected ECs isolated from peripheral blood. Moreover, overexpression of miR-133 drastically reduced the rate of cell division and disturbed capillary network formation of transfected ECs. These findings suggest that miR-133 plays an important function in bFGF-induced angiogenesis processes in ECs and provides a rationale for new therapeutic approaches to suppress tumor angiogenesis and cancer.

Functional SNP in microRNA-491-5p binding site of MMP9 3'-UTR affects cancer susceptibility.

MicroRNAs (miRNA) are small RNA molecules that negatively regulate gene expression through base pairing interactions between 3'-UTR of the target mRNAs and seed sequence of miRNA. Any changes in the recognition site could destroy binding sites or modify binding affinity, resulting in evasion from miRNA regulation. A putative binding site for miR-491-5p resides in 3'-UTR of MMP9, and a genetic variant (rs1056628 A → C) is present in this region. The role of MMP9 over expression well marked in various cancers. However, whether rs1056628 SNP in miR-491-5p binding site of MMP9 3'-UTR could abrogate its post-transcriptional regulation and affect cancer susceptibility remains largely unknown. To test this, the rs1056628 SNP was genotyped in 300 cases of lung, gastric and breast cancers and 200 age- and sex-matched healthy controls. The results showed that compared with the AA genotype, C was a risk genotype for all three cancers development and was also associated with gastric and breast cancers metastasis and invasion. Based on the base pairing analysis and secondary structure evaluation of MMP9 mRNA and miR-491-5p, we found that miR-491-5p had a higher binding affinity for A genotype than the C genotype. The Luciferase activity of MMP9 3'-UTR indicates differential regulation of two genetic variations of MMP9. Overexpression of miR-491-5p decreased MMP9 mRNA level in cell lines of gastric, breast and lung cancers and thus leads to decreasing of the invasion ability. Therefore, for the first time we imply that the C variant of MMP9 contributes to the likelihood of gastric, breast and lung cancers susceptibility via a novel mechanism of subtle gene regulation through miRNA binding capacity.

Survival Improvement in Human Retinal Pigment Epithelial Cells via Fas Receptor Targeting by miR-374a.

Oxidative conditions of the eye could contribute to retinal cells loss through activating the Fas-L/Fas pathway. This phenomenon is one of the leading causes of some ocular diseases like age-related macular degeneration (AMD). By targeting proteins at their mRNA level, microRNAs (miRNAs) can regulate gene expression and cell function. The aim of the present study is to investigate Fas targeting by miR-374a and find whether it can inhibit Fas-mediated apoptosis in primary human retinal pigment epithelial (RPE) cells under oxidative stress. So, the primary human RPE cells were transfected with pre-miR-374a pLEX construct using polymeric carrier and were exposed to H2 O2 (200 µM) as an oxidant agent for induction of Fas expression. Fas expression at mRNA and protein level was evaluated by quantitative real-time PCR and Western blot analysis, respectively. These results revealed that miR-374a could prevent Fas upregulation under oxidative conditions. Moreover, Luciferase activity assay confirmed that Fas could be a direct target of miR-374a. The cell viability studies demonstrated that caspase-3 activity was negligible in miR-374a treated cells compared to the controls. Our data suggest miR-374a is a negative regulator of Fas death receptor which is able to enhance the cell survival and protect RPE cells against oxidative conditions. J. Cell. Biochem. 118: 4854-4861, 2017. © 2017 Wiley Periodicals, Inc.

Efficient gene delivery to primary human retinal pigment epithelial cells: The innate and acquired properties of vectors.

The purpose of this study is designing non-viral gene delivery vectors for transfection of the primary human retinal pigment epithelial cells (RPE). In the design process of gene delivery vectors, considering physicochemical properties of vectors alone does not seem to be enough since they interact with constituents of the surrounding environment and hence gain new characteristics. Moreover, due to these interactions, their cargo can be released untimely or undergo degradation before reaching to the target cells. Further, the characteristics of cells itself can also influence the transfection efficacy. For example, the non-dividing property of RPE cells can impede the transfection efficiency which in most studies was ignored by using immortal cell lines. In this study, vectors with different characteristics differing in mixing orders of pDNA, PEI polymer, and PLGA/PEI or PLGA nanoparticles were prepared and characterized. Then, their characteristics and efficacy in gene delivery to RPE cells in the presence of vitreous or fetal bovine serum (FBS) were evaluated. All formulations showed no cytotoxicity and were able to protect pDNA from premature release and degradation in extracellular media. Also, the adsorption of vitreous or serum proteins onto the surface of vectors changed their properties and hence cellular uptake and transfection efficacy.

Overexpression of microRNA-16 declines cellular growth, proliferation and induces apoptosis in human breast cancer cells.

MicroRNAs (miRNA) are a large family of small single-stranded RNA molecules found in all multicellular organisms. Early studies have been shown that miRNA are involved in cancer development and progression, and this role can be done by working as an oncogenes and tumor suppressor genes, so manipulation of this molecules can be a promising approach in cancer therapy, and experimental results represented that the modification in breast cancer phenotype is possible by miRNA expression alteration. miR-16, which is located in 13q14 chromosome, plays critical roles as a tumor suppressor by targeting several oncogenes which regulate cell cycle and apoptosis. Hence, in the present study, we investigated whether miR-16 could decline growth and survival of MCF-7 cell line as model of human breast cancer. MCF-7 cell line was infected with lentiviruses containing miR-16 precursor sequence. The effects of ectopic expression of miR-16 on breast cancer phenotype were examined by cell cycle analysis and apoptosis assays. miR-16 cytotoxicity effect was measured by the MTT assay. We showed that the miR-16 overexpression reduces Cyclin D1 and BCL2 at messenger RNA (mRNA) and protein levels in MCF-7 cell line. In addition, this is found that enforced expression of miR-16 decreases cell growth and proliferation and induces apoptosis in MCF-7 cells. In conclusion, our results revealed that upregulation of miR-16 would be a potential approach for breast cancer therapy.