Project description:Epithelial-mesenchymal interactions play a crucial role in branching morphogenesis, but very little is known about how endothelial cells contribute to this process. Here, we examined how anti-angiogenic miR-221 and pro-angiogenic miR-130a affect airway and vascular development in the fetal lungs. Lung-specific effects of miR-130a and miR-221 were studied in mouse E14 whole lungs cultured for 48 hours with anti-miRs or mimics to miR-130a and miR-221. Anti-miR 221 treated lungs had more distal branch generations with increased Hoxb5 and VEGFR2 around airways. Conversely, mimic 221 treated lungs had reduced airway branching, dilated airway tips and decreased Hoxb5 and VEGFR2 in mesenchyme. Anti-miR 130a treatment led to reduced airway branching with increased Hoxa5 and decreased VEGFR2 in the mesenchyme. Conversely, mimic 130a treated lungs had numerous finely arborized branches extending into central lung regions with diffusely localized Hoxa5 and increased VEGFR2 in the mesenchyme. Vascular morphology was analyzed by GSL-B4 (endothelial cell-specific lectin) immunofluorescence. Observed changes in airway morphology following miR-221 inhibition and miR-130a enhancement were mirrored by changes in vascular plexus formation around the terminal airways. Mouse fetal lung endothelial cells (MFLM-91U) were used to study microvascular cell behavior. Mimic 221 treatment resulted in reduced tube formation and cell migration, where as the reverse was observed with mimic 130a treatment. From these data, we conclude that miR-221 and miR-130a have opposing effects on airway and vascular morphogenesis of the developing lung.
Project description:Endothelial cells play essential roles in maintenance of vascular integrity, angiogenesis, and wound repair. We show that an endothelial cell-restricted microRNA (miR-126) mediates developmental angiogenesis in vivo. Targeted deletion of miR-126 in mice causes leaky vessels, hemorrhaging, and partial embryonic lethality, due to a loss of vascular integrity and defects in endothelial cell proliferation, migration, and angiogenesis. The subset of mutant animals that survives displays defective cardiac neovascularization following myocardial infarction. The vascular abnormalities of miR-126 mutant mice resemble the consequences of diminished signaling by angiogenic growth factors, such as VEGF and FGF. Accordingly, miR-126 enhances the proangiogenic actions of VEGF and FGF and promotes blood vessel formation by repressing the expression of Spred-1, an intracellular inhibitor of angiogenic signaling. These findings have important therapeutic implications for a variety of disorders involving abnormal angiogenesis and vascular leakage.
Project description:It is known that chronic stress modulates multiple processes in a complex microenvironment, such as angiogenesis and immune function. However, the role of chronic stress inducing tumor angiogenesis and how it contributes to tumor progression are not quite clear. The following study assess psychological state from numerous ambulatory cancer cases (n=332), and chronic stress-related hormone levels were further measured. Here, we show that chronic stress not only causes behavioral changes in human, most importantly attributed to an elevated level of stress-related hormones. To address this, isoprenaline, the agonist of β2-adrenergic receptor (β2-AR), was utilized for simulating chronic stress and demonstrating the mechanism of stress in tumor angiogenesis at molecular level both in vivo and in vitro. As suggested by this study, isoprenaline promote VEGF autocrine of HUVECs, which can induce plexinA1 and VEGFR2 expression. Moreover, we show that isoprenaline promoted the expression of p-JAK2 and p-STAT3 in vitro. The results reveal that, isoprenaline enhances the autocrine of VEGF in HUVECs and up-regulating plexinA1 and VEGFR2 levels, thus activating the phosphorylation of JAK2-STAT3 pathway, the two essential parts during angiogenesis. The present work indicates that, the mechanism of chronic stress in enhancing angiogenesis is probably achieved through activating the plexinA1/VEGFR2-JAK2-STAT3 signal transduction pathway within HUVECs, and this is probably a candidate target for developing a strategy against angiogenesis in cancer.
Project description:Recent evidence has suggested an important role of miRNAs in liver biology and diseases, although the implication of miRNAs in cholangiocarcinoma remains to be defined further. This study was designed to examine the biological function and molecular mechanism of miR-101 in cholangiocarcinogenesis and tumor progression. In situ hybridization and quantitative RT-PCR were performed to determine the expression of miR-101 in human cholangiocarcinoma tissues and cell lines. Compared with noncancerous biliary epithelial cells, the expression of miR-101 is decreased in 43.5% of human cholangiocarcinoma specimens and in all three cholangiocarcinoma cell lines used in this study. Forced overexpression of miR-101 significantly inhibited cholangiocarcinoma growth in severe combined immunodeficiency mice. miR-101-overexpressed xenograft tumor tissues showed decreased capillary densities and decreased levels of vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2). The VEGF and COX-2 mRNAs were identified as the bona fide targets of miR-101 in cholangiocarcinoma cells by both computational analysis and experimental assays. miR-101 inhibits cholangiocarcinoma angiogenesis by direct targeting of VEGF mRNA 3'untranslated region and by repression of VEGF gene transcription through inhibition of COX-2. This study established a novel tumor-suppressor role of miR-101 in cholangiocarcinoma and it suggests the possibility of targeting miR-101 and related signaling pathways for future therapy.
Project description:Remodeling of the primitive vasculature is necessary for the formation of a complex branched vascular architecture. However, the factors that modulate these processes are incompletely defined. Previously, we defined the role of microRNAs (miRNAs) in endothelial specification. In the present study, we further examined the Etv2-Cre mediated ablation of DicerL/L and characterized the perturbed vascular patterning in the embryo proper and yolk-sac. We mechanistically defined an important role for miR-130a, an Etv2 downstream target, in the mediation of vascular patterning and angiogenesis in vitro and in vivo. Inducible overexpression of miR-130a resulted in robust induction of vascular sprouts and angiogenesis with increased uptake of acetylated-LDL. Mechanistically, miR-130a directly regulated Jarid2 expression by binding to its 3'-UTR region. Over-expression of Jarid2 in HUVEC cells led to defective tube formation indicating its inhibitory role in angiogenesis. The knockout of miR-130a showed increased levels of Jarid2 in the ES/EB system. In addition, the levels of Jarid2 transcripts were increased in the Etv2-null embryos at E8.5. In the in vivo settings, injection of miR-130a specific morpholinos in zebrafish embryos resulted in perturbed vascular patterning with reduced levels of endothelial transcripts in the miR-130a morphants. Further, co-injection of miR-130a mimics in the miR-130a morphants rescued the vascular defects during embryogenesis. qPCR and in situ hybridization techniques demonstrated increased expression of jarid2a in the miR-130a morphants in vivo. These findings demonstrate a critical role for Etv2-miR-130a-Jarid2 in vascular patterning both in vitro and in vivo.
Project description:Hypoxia modulates reparative angiogenesis, which is a tightly regulated pathophysiological process. MicroRNAs (miRNAs) are important regulators of gene expression in hypoxia and angiogenesis. However, we do not yet have a clear understanding of how hypoxia-induced miRNAs fine-tune vasoreparative processes. Here, we identify miR-130a as a mediator of the hypoxic response in human primary endothelial colony-forming cells (ECFCs), a well-characterized subtype of endothelial progenitors. Under hypoxic conditions of 1% O2, miR-130a gain-of-function enhances ECFC pro-angiogenic capacity in vitro and potentiates their vasoreparative properties in vivo. Mechanistically, miR-130a orchestrates upregulation of VEGFR2, activation of STAT3, and accumulation of HIF1α via translational inhibition of Ddx6. These findings unveil a new role for miR-130a in hypoxia, whereby it activates the VEGFR2/STAT3/HIF1α axis to enhance the vasoregenerative capacity of ECFCs.
Project description:Many diseases, including cancer, have been associated with impaired regulation of angiogenesis, of which vascular endothelial growth factor (VEGF)-A is a key regulator. Here, we test the contribution of N-myc downstream regulated gene 1 (NDRG1) to VEGF-A-induced angiogenesis in vascular endothelial cells (ECs). Ndrg1-/- mice exhibit impaired VEGF-A-induced angiogenesis in corneas. Tumor angiogenesis induced by cancer cells that express high levels of VEGF-A was also reduced in a mouse dorsal air sac assay. Furthermore, NDRG1 deficiency in ECs prevented angiogenic sprouting from the aorta and the activation of phospholipase Cγ1 (PLCγ1) and ERK1/2 by VEGF-A without affecting the expression and function of VEGFR2. Finally, we show that NDRG1 formed a complex with PLCγ1 through its phosphorylation sites, and the inhibition of PLCγ1 dramatically suppressed VEGF-A-induced angiogenesis in the mouse cornea, suggesting an essential role of NDRG1 in VEGF-A-induced angiogenesis through PLCγ1 signaling.
Project description:BackgroundVascular dementia (VaD) mainly results from cerebral vascular lesions and tissue changes, which contribute to neurodegenerative processes. Effective therapeutic approaches to targeting angiogenesis may reduce mortality of VaD. Endothelial progenitor cells (EPCs) play a key role in postnatal angiogenesis. Many exosomal microRNAs (exo-miRNAs) have been reported to involve in the development of dementia. The present study was designed to investigate whether the expression profile of the exo-miRNAs is significantly altered in patients with VaD and to reveal the function of differentially expressed miRNAs and the relevant mechanisms in EPC-mediated angiogenesis in VaD rat model.ResultsExosomes isolated from serum of patients with VaD (n = 7) and age-matched control subjects (n = 7), and miRNA sequencing and bioinformatics analysis found that circulating exosome miRNA-155-5p, miRNA-154-5p, miR-132-5p, and miR-1294 were upregulated in patients with VaD. The expression of miRNA-154-5p was further verified to be upregulated in clinical samples (n = 23) and 2-vessel occlusion-induced VaD rat model by reverse transcription quantitative PCR (RT-qPCR). Notably, miRNA-154-5p inhibition in bone marrow-EPCs (BM-EPCs) from VaD rats improved EPC functions, including tube formation, migration, and adhesion, and elevated concentrations of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1α (SDF-1α). The mRNA levels of ICAM-1, VCAM-1, and MCP-1 were reduced in miRNA-154-5p-inhibited EPCs. In addition, miRNA-154-5p inhibition increased the level of superoxide dismutase (SOD), and decreased reactive oxygen species (ROS) in EPCs. PRKAA2 was chosen as a promising target gene of miR-154-5p, and miRNA-154-5p inhibition upregulated the protein expression of AMPKα2. Furthermore, upregulation of miR-154-5p markedly diminished EPC functions and inhibited angiogenesis following EPC transplantation in VaD rats.ConclusionCirculating exo-miR-154-5p was upregulated in patients with VaD, and miR-154-5p upregulation was associated with impaired EPC functions and angiogenesis in VaD rat model. Therefore, miR-154-5p is a promising biomarker and therapeutic strategy for VaD.
Project description:Anosmin-1 is a secreted glycoprotein encoded by the ANOS1 gene, and its loss of function causes Kallmann syndrome (KS), which is characterized by anosmia and hypogonadism due to olfactory bulb (OB) dysfunction. However, the physiological function of anosmin-1 remains to be elucidated. In KS, disordered angiogenesis is observed in OB, resulting in its hypoplasia. In this study, we examined the involvement of anosmin-1 in angiogenic processes. Anosmin-1 was detected on the vessel-like structure in OB of chick embryos, and promoted the outgrowth of vascular sprouts as shown by assays of OB tissue culture. Cell migration, proliferation, and tube formation of endothelial cells were induced by treatment with anosmin-1 as well as vascular endothelial growth factor-A (VEGF-A), and further enhanced by treatment with both of them. We newly identified that anosmin-1 activated VEGF receptor-2 (VEGFR2) by binding directly to it, and its downstream signaling molecules, phospholipase C?1 (PLC?1) and protein kinase C (PKC). These results suggest that anosmin-1 plays a key role in the angiogenesis of developing OB through the VEGFR2-PLC?1-PKC axis by enhancing the VEGF function.