Formation and remodeling of the vasculature during development and disease involve a highly conserved and precisely regulated network of attractants and repellants. Various signaling pathways control the behavior of endothelial cells, but their posttranscriptional dose titration by microRNAs is poorly understood.
To identify microRNAs that regulate angiogenesis.
Methods and results:
We show that the highly conserved microRNA family encoding miR-10 regulates the behavior of endothelial cells during angiogenesis by positively titrating proangiogenic signaling. Knockdown of miR-10 led to premature truncation of intersegmental vessel growth in the trunk of zebrafish larvae, whereas overexpression of miR-10 promoted angiogenic behavior in zebrafish and cultured human umbilical venous endothelial cells. We found that miR-10 functions, in part, by directly regulating the level of fms-related tyrosine kinase 1 (FLT1), a cell-surface protein that sequesters vascular endothelial growth factor, and its soluble splice variant sFLT1. The increase in FLT1/sFLT1 protein levels upon miR-10 knockdown in zebrafish and in human umbilical venous endothelial cells inhibited the angiogenic behavior of endothelial cells largely by antagonizing vascular endothelial growth factor receptor 2 signaling.
Our study provides insights into how FLT1 and vascular endothelial growth factor receptor 2 signaling is titrated in a microRNA-mediated manner and establishes miR-10 as a potential new target for the selective modulation of angiogenesis.
"MiR-145 indirectly down-regulates VEGF in cancer cells to inhibit tumor growth and angiogenesis by targeting p70S6K1, an upstream molecule of VEGF . MiR-10 indirectly down-regulates VEGF-mediated angiogenesis in HUVECs by targeting fms-related tyrosine kinase 1 (FLT1), a cell-surface protein that sequesters VEGF . However, miR-15b, miR-16, miR-20a, miR-20b , , miR-205  and miR-195  down-regulate angiogenesis by directly targeting VEGF. "
[Show abstract][Hide abstract] ABSTRACT: MicroRNAs have been appreciated in various cellular functions, including the regulation of angiogenesis. Mesenchymal-stem-cells (MSCs) transplanted to the MI heart improve cardiac function through paracrine-mediated angiogenesis. However, whether microRNAs regulate MSC induced angiogenesis remains to be clarified. Using microRNA microarray analysis, we identified a microRNA expression profile in hypoxia-treated MSCs and observed that among all dysregulated microRNAs, microRNA-377 was decreased the most significantly. We also validated that vascular endothelial growth factor (VEGF) is a target of microRNA-377 using dual-luciferase reporter assay and Western-blotting. Knockdown of endogenous microRNA-377 promoted tube formation in human umbilical vein endothelial cells. We then engineered rat MSCs with lentiviral vectors to either overexpress microRNA-377 (MSCmiR-377) or knockdown microRNA-377 (MSCAnti-377) to investigate whether microRNA-377 regulated MSC-induced myocardial angiogenesis, using MSCs infected with lentiviral empty vector to serve as controls (MSCNull). Four weeks after implantation of the microRNA-engineered MSCs into the infarcted rat hearts, the vessel density was significantly increased in MSCAnti-377-hearts, and this was accompanied by reduced fibrosis and improved myocardial function as compared to controls. Adverse effects were observed in MSCmiR-377-treated hearts, including reduced vessel density, impaired myocardial function, and increased fibrosis in comparison with MSCNull-group. These findings indicate that hypoxia-responsive microRNA-377 directly targets VEGF in MSCs, and knockdown of endogenous microRNA-377 promotes MSC-induced angiogenesis in the infarcted myocardium. Thus, microRNA-377 may serve as a novel therapeutic target for stem cell-based treatment of ischemic heart disease.
PLoS ONE 09/2014; 9(9):e104666. DOI:10.1371/journal.pone.0104666 · 3.23 Impact Factor
"miR-10 acts by directly regulating FLT1 (a cell-surface receptor that binds VEGF) and its soluble splice variant SFLT1. Its downregulation in zebrafish and HUVECs increases FLT1/SFLT1 protein levels, which binds VEGF with higher affinity than VEGFR-2 and therefore negatively regulates VEGFR-2 signalling pathway . Moreover, miR-10b and miR-196b have been related to angiogenesis and cancer metastasis [125–129] and are both upregulated in murine ECs treated with tumour-conditioned medium, although only miR-10 responded to increased VEGF levels. "
[Show abstract][Hide abstract] ABSTRACT: MicroRNAs are one class of small, endogenous, non-coding RNAs that are approximately 22 nucleotides in length; they are very numerous, have been phylogenetically conserved, and involved in biological processes such as development, differentiation, cell proliferation, and apoptosis. MicroRNAs contribute to modulating the expression levels of specific proteins based on sequence complementarity with their target mRNA molecules and so they play a key role in both health and disease. Angiogenesis is the process of new blood vessel formation from preexisting ones, which is particularly relevant to cancer and its progression. Over the last few years, microRNAs have emerged as critical regulators of signalling pathways in multiple cell types including endothelial and perivascular cells. This review summarises the role of miRNAs in tumour angiogenesis and their potential implications as therapeutic targets in cancer.
BioMed Research International 08/2014; 2014:878450. DOI:10.1155/2014/878450 · 3.17 Impact Factor
"On the one hand, some miRNAs, such as miR-205 and miR-492, were shown to directly inhibit VEGF expression in human endothelial cells and cancer cells  . On the other hand, VEGF signaling can be modulated indirectly via miRNAmediated repression of the expression of VEGF receptor 1 (VEGFR1, FLT1), nuclear factor kappa B (NFí µí¼ B), and Spred-1    . However, little is known about the role of miRNAs in regulation of VEGF-mediated vascular tone control. "
[Show abstract][Hide abstract] ABSTRACT: Posttranscriptional control of gene expression is crucial for regulating plurality of proteins and functional plasticity of the proteome under (patho)physiologic conditions. Alternative splicing as well as micro (mi)RNA-mediated mechanisms play an important role for the regulation of protein expression on posttranscriptional level. Both alternative splicing and miRNAs were shown to influence cardiovascular functions, such as endothelial thrombogenicity and the vascular tone, by regulating the expression of several vascular proteins and their isoforms, such as Tissue Factor (TF) or the endothelial nitric oxide synthase (eNOS). This review will summarize and discuss the latest findings on the (patho)physiologic role of alternative splicing processes as well as of miRNAs on modulation of vascular functions, such as coagulation, thrombosis, and regulation of the vascular tone.
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