Evaluation of the plasma microRNA levels in stage 3 premature retinopathy with plus disease: preliminary study

PurposeIn the present study, we aimed to investigate the changes in plasma microRNA (miRNA) levels in premature infants diagnosed with premature retinopathy (ROP).Patients and methodsIn order to investigate the relationship of miRNAs with ROP, 13 premature infants admitted to Mersin University, Medical School, Department of Ophthalmology and diagnosed with ROP stage 3 with plus disease between January 2014-January 2015 were included in the study. Control group consisted of 15 premature infants with no ROP. The plasma miRNA levels were evaluated using high-throughput quantitative real-time PCR.ResultsThe results of study demonstrated that the expression level of miR-23a and miR-200b-3p was significantly upregulated in patients with ROP when compared with the control group (P<0.05). The expression level of miR-27b-3p and miR-214-3p was significantly downregulated in patients (P<0.05). In addition, expression of 17 miRNA (miR-410-3p, miR-17-5p, miR-451a, miR-31-5p, miR-132-3p, miR-183-5p, miR-184, miR-222-3p, miR-296-5p, miR-200a-3p, miR-328-3p,miR-96-5p, miR-199a-5p, miR-99a-5p, miR-106a-5p, miR-125b-5p, miR-155-5p) had upregulated or downregulated, but not statistically significantly different when compared with the control group.ConclusionsOur results suggest that plasma miRNA levels may alter in ROP and, some miRNAs might have an effect in the physiopathology of this disease. These molecules may have an important therapeutic role in patients who are unresponsive to anti-vascular endothelial growth factor therapy. However, further studies must be conducted for possible effects of miRNAs in vascular disorders of eye such as ROP. Moreover to define the relationship of these molecules with the disease more clearly, a multicenter study including more patients is necessary.

MicroRNA-214 regulates smooth muscle cell differentiation from stem cells by targeting RNA-binding protein QKI

MicroRNA-214(miR-214) has been recently reported to regulate angiogenesis and embryonic stem cells (ESCs) differentiation. However, very little is known about its functional role in vascular smooth muscle cells (VSMCs) differentiation from ESCs. In the present study, we assessed the hypothesis that miR-214 and its target genes play an important role in VSMCs differentiation. Murine ESCs were seeded on collagen-coated flasks and cultured in differentiation medium for 2 to 8 days to allow VSMCs differentiation. miR-214 was significantly upregulated during VSMCs differentiation. miR-214 overexpression and knockdown in differentiating ESCs significantly promoted and inhibited VSMCs -specific genes expression, respectively. Importantly, miR-214 overexpression in ESCs promoted VSMCs differentiation in vivo. Quaking (QKI) was predicted as one of the major targets of miR-214, which was negatively regulated by miR-214. Luciferase assay showed miR-214 substantially inhibited wild type, but not the mutant version of QKI-3-UTR-luciferase activity in differentiating ESCs, further confirming a negative regulation role of miR-214 in QKI gene expression. Mechanistically, our data showed that miR-214 regulated VSMCs gene expression during VSMCs differentiation from ESCs through suppression of QKI. We further demonstrated that QKI down-regulated the expression of SRF, MEF2C and Myocd through transcriptional repression and direct binding to promoters of the SRF, MEF2c and Myocd genes. Taken together, we have uncovered a central role of miR-214 in ESC-VSMC differentiation, and successfully identified QKI as a functional modulating target in miR-214 mediated VSMCs differentiation.

The role of miR-214 in cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of death throughout the world. The increase in new patients every year leads to a demand for the identification of valid and novel prognostic and diagnostic biomarkers for the prevention and treatment of cardiovascular diseases. MicroRNAs (miRNAs) are critical endogenous small noncoding RNAs that negatively modulate gene expression by regulating its translation. miRNAs are implicated in most physiological processes of the heart and in the pathological progression of cardiovascular diseases. miR-214 is a deregulated miRNA in many pathological conditions, and it contributes to the pathogenesis of multiple human disorders, including cancer and cardiovascular diseases. miR-214 has dual functions in different cardiac pathological circumstances. However, it is considered as a promising marker in the prognosis, diagnosis and treatment of cardiovascular diseases. In this review, we discuss the role of miR-214 in various cardiac disease conditions, including ischaemic heart diseases, cardiac hypertrophy, pulmonary arterial hypertension (PAH), angiogenesis following vascular injury and heart failure.

MicroRNA-214 modulates neural progenitor cell differentiation by targeting Quaking during cerebral cortex development

The accurate generation of an appropriate number of different neuronal and glial subtypes is fundamental to normal brain functions and requires tightly orchestrated spatial and temporal developmental programmes to maintain the balance between the proliferation and the differentiation of neural progenitor cells. However, the molecular mechanism governing this process has not been fully elucidated. Here, we found that miR-214-3p was highly expressed in neural progenitor cells and dynamically regulated during neocortical development. Moreover, our in vivo and in vitro studies showed that miR-214 inhibited self-renewal of neural progenitor cells and promoted neurogenesis. In addition, after target screening, we identified miR-214 targets including Quaking (Qki) by binding the 3'- untranslated region (3'-UTR) of the Qki mRNA, which was specifically expressed in the progenitor cells of the proliferative ventricular zone as 3 Qki isoforms. Furthermore, overexpression and knockdown of Qki showed that the different isoforms of Qki had different functions in the regulation of neural progenitor cells differentiation. Moreover, overexpression of Qki could counteract the function of miR-214 in neurogenesis. Our results revealed that miR-214 maintains the balance between neural progenitor/stem cell proliferation and differentiation together with Quaking, its target gene.

SCA1+ Cells from the Heart Possess a Molecular Circadian Clock and Display Circadian Oscillations in Cellular Functions

Stem cell antigen 1-positive (SCA1⁺) cells (SPCs) have been investigated in cell-based cardiac repair and pharmacological research, although improved cardiac function after injection has been variable and the mode of action remains unclear. Circadian (24-hr) rhythms are biorhythms regulated by molecular clocks that play an important role in (patho)physiology. Here, we describe (1) the presence of a molecular circadian clock in SPCs and (2) circadian rhythmicity in SPC function. We isolated SPCs from human fetal heart and found that these cells possess a molecular clock based on typical oscillations in core clock components BMAL1 and CRY1. Functional analyses revealed that circadian rhythmicity also governs SPC proliferation, stress tolerance, and growth factor release, with large differences between peaks and troughs. We conclude that SPCs contain a circadian molecular clock that controls crucial cellular functions. Taking circadian rhythms into account may improve reproducibility and outcome of research and therapies using SPCs.

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SCA1⁺ cells are a cell source used in pharmacology studies and cardiac repair

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SCA1⁺ cells possess a molecular circadian (24-hr) clock

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Proliferation, stress tolerance, and paracrine secretion follow a circadian pattern

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Taking rhythmicity into account may improve studies using SCA1⁺ cells

Expression of miR-126 and its potential function in coronary artery disease

OBJECTIVE

This study aimed to explore the role of miR-126 in coronary artery disease (CAD) patients and the potential gene targets of miR-126 in atherosclerosis.

METHODOLOGY

A total of 60 CAD patients and 25 healthy control subjects were recruited in this study. Among the 60 CAD patients, 18 cases were diagnosed of stable angina pectoris (SAP), 20 were diagnosed of unstable angina pectoris (UAP) and 22 were diagnosed of acute myocardial infarction (AMI). Plasma miR-126 levels from both groups of participants were analyzed by real-time quantitative PCR. ELISA was used to measure plasma level of placenta growth factor (PLGF).

RESULTS

The results showed that the miR-126 expression was significantly down-regulated in the circulation of CAD patients compared with control subjects (P<0.01). Plasma PLGF level was significantly upregulated in patients with unstable angina pectoris and acute myocardial infarction (AMI) compared with controls (both P<0.01) the miR-126 expression in AMI was significantly associated with PLGF.

CONCLUSION

miR-126 may serve as a novel biomarker for CAD.

Quaking Is a Key Regulator of Endothelial Cell Differentiation, Neovascularization, and Angiogenesis

The capability to derive endothelial cell (ECs) from induced pluripotent stem cells (iPSCs) holds huge therapeutic potential for cardiovascular disease. This study elucidates the precise role of the RNA‐binding protein Quaking isoform 5 (QKI‐5) during EC differentiation from both mouse and human iPSCs (hiPSCs) and dissects how RNA‐binding proteins can improve differentiation efficiency toward cell therapy for important vascular diseases. iPSCs represent an attractive cellular approach for regenerative medicine today as they can be used to generate patient‐specific therapeutic cells toward autologous cell therapy. In this study, using the model of iPSCs differentiation toward ECs, the QKI‐5 was found to be an important regulator of STAT3 stabilization and vascular endothelial growth factor receptor 2 (VEGFR2) activation during the EC differentiation process. QKI‐5 was induced during EC differentiation, resulting in stabilization of STAT3 expression and modulation of VEGFR2 transcriptional activation as well as VEGF secretion through direct binding to the 3′ UTR of STAT3. Importantly, mouse iPS‐ECs overexpressing QKI‐5 significantly improved angiogenesis and neovascularization and blood flow recovery in experimental hind limb ischemia. Notably, hiPSCs overexpressing QKI‐5, induced angiogenesis on Matrigel plug assays in vivo only 7 days after subcutaneous injection in SCID mice. These results highlight a clear functional benefit of QKI‐5 in neovascularization, blood flow recovery, and angiogenesis. Thus, they provide support to the growing consensus that elucidation of the molecular mechanisms underlying EC differentiation will ultimately advance stem cell regenerative therapy and eventually make the treatment of cardiovascular disease a reality. The RNA binding protein QKI‐5 is induced during EC differentiation from iPSCs. RNA binding protein QKI‐5 was induced during EC differentiation in parallel with the EC marker CD144. Immunofluorescence staining showing that QKI‐5 is localized in the nucleus and stained in parallel with CD144 in differentiated ECs (scale bar = 50 µm). stemcells2017 Stem Cells2017;35:952–966

Regulation of microvascularization in heart failure - an endothelial cell, non-coding RNAs and exosome liaison

Heart failure is a complex syndrome involving various pathophysiological processes. An increasing body of evidence shows that the myocardial microvasculature is essential for the homeostasis state and that a decompensated heart is associated with microvascular dysfunction as a result of impaired endothelial angiogenic capacity. The intercellular communication between endothelial cells and cardiomyocytes through various signaling molecules, such as vascular endothelial growth factor, nitric oxide, and non-coding RNAs is an important determinant of cardiac microvascular function. Non-coding RNAs are transported from endothelial cells to cardiomyocytes, and vice versa, regulating microvascular properties and angiogenic processes in the heart. Small-exocytosed vesicles, called exosomes, which are secreted by both cell types, can mediate this intercellular communication. The purpose of this review is to highlight the contribution of the microvasculature to proper heart function maintenance by focusing on the interaction between cardiac endothelial cells and myocytes with a specific emphasis on non-coding RNAs (ncRNAs) in this form of cell-to-cell communication. Finally, the potential of ncRNAs as targets for angiogenesis therapy will also be discussed.

NCK Associated Protein 1 Modulated by miRNA-214 Determines Vascular Smooth Muscle Cell Migration, Proliferation, and Neointima Hyperplasia

BACKGROUND

MicroRNA miR-214 has been implicated in many biological cellular functions, but the impact of miR-214 and its target genes on vascular smooth muscle cell (VSMC) proliferation, migration, and neointima smooth muscle cell hyperplasia is unknown.

METHODS AND RESULTS

Expression of miR-214 was closely regulated by different pathogenic stimuli in VSMCs through a transcriptional mechanism and decreased in response to vascular injury. Overexpression of miR-214 in serum-starved VSMCs significantly decreased VSMC proliferation and migration, whereas knockdown of miR-214 dramatically increased VSMC proliferation and migration. Gene and protein biochemical assays, including proteomic analyses, showed that NCK associated protein 1 (NCKAP1)-a major component of the WAVE complex that regulates lamellipodia formation and cell motility-was negatively regulated by miR-214 in VSMCs. Luciferase assays showed that miR-214 substantially repressed wild-type but not the miR-214 binding site mutated version of NCKAP1 3' untranslated region luciferase activity in VSMCs. This result confirmed that NCKAP1 is the functional target of miR-214 in VSMCs. NCKAP1 knockdown in VSMCs recapitulates the inhibitory effects of miR-214 overexpression on actin polymerization, cell migration, and proliferation. Data from cotransfection experiments also revealed that inhibition of NCKAP1 is required for miR-214-mediated lamellipodia formation, cell motility, and growth. Importantly, locally enforced expression of miR-214 in the injured vessels significantly reduced NCKAP1 expression levels, inhibited VSMC proliferation, and prevented neointima smooth muscle cell hyperplasia after injury.

CONCLUSIONS

We uncovered an important role of miR-214 and its target gene NCKAP1 in modulating VSMC functions and neointima hyperplasia. Our findings suggest that miR-214 represents a potential therapeutic target for vascular diseases.

Exosomes from Cardiomyocyte Progenitor Cells and Mesenchymal Stem Cells Stimulate Angiogenesis Via EMMPRIN

To date, cellular transplantation therapy has not yet fulfilled its high expectations for cardiac repair. A major limiting factor is lack of long-term engraftment of the transplanted cells. Interestingly, transplanted cells can positively affect their environment via secreted paracrine factors, among which are extracellular vesicles, including exosomes: small bi-lipid-layered vesicles containing proteins, mRNAs, and miRNAs. An exosome-based therapy will therefore relay a plethora of effects, without some of the limiting factors of cell therapy. Since cardiomyocyte progenitor cells (CMPC) and mesenchymal stem cells (MSC) induce vessel formation and are frequently investigated for cardiac-related therapies, the pro-angiogenic properties of CMPC and MSC-derived exosome-like vesicles are investigated. Both cell types secrete exosome-like vesicles, which are efficiently taken up by endothelial cells. Endothelial cell migration and vessel formation are stimulated by these exosomes in in vitro models, mediated via ERK/Akt-signaling. Additionally, these exosomes stimulated blood vessel formation into matrigel plugs. Analysis of pro-angiogenic factors revealed high levels of extracellular matrix metalloproteinase inducer (EMMPRIN). Knockdown of EMMPRIN on CMPCs leads to a diminished pro-angiogenic effect, both in vitro and in vivo. Therefore, CMPC and MSC exosomes have powerful pro-angiogenic effects, and this effect is largely mediated via the presence of EMMPRIN on exosomes.

Lanthanide Hydroxide Nanoparticles Induce Angiogenesis via ROS-Sensitive Signaling

Recent studies suggest that the nanorods consisting of europium hydroxide could promote angiogenesis. In this study, it is sought to determine if additional types of nanoparticles are capable of enhancing angiogenesis and in addition, understand the underlying mechanisms. For this reason, a method is employed that combines a high throughput in vitro cell based screen coupled with an in vivo validation using vascular specific green fluorescent protein reporter transgenic zebrafish for examining proangiogenesis activity. After screening multiple types of nanoparticles, it is discovered that four of them, Eu(III) (OH)3 rods (Eu rods), Eu(III) (OH)3 spheres (Eu spheres), Tb(III) (OH)3 rods (Tb rods), and Tb(III) (OH)3 spheres (Tb spheres), are the most effective in promoting angiogenesis. It is also showed that ionic forms of europium nitrate [Eu(NO3 )3 ] (Eu) and terbium nitrate [Tb(NO3 )3 ] (Tb), the two lanthanide elements for these four nanoparticles, are also capable of enhancing angiogenesis. However, this effect is further enhanced by nanoparticle synthesis. Finally, it is demonstrated that reactive oxygen species H2 O2 is a key factor in the process of proangiogenesis by lanthanide elemental nanoparticles.

Delivering therapeutics in peripheral artery disease: challenges and future perspectives

Targeted and sustained delivery of biologicals to improve neovascularization has been focused on stimulation angiogenesis. The formation of collaterals however is hemodynamically much more efficient, but as a target of therapy has been under-utilized. Although there is good understanding of the molecular processes involving collateral formation and there are interesting drugable candidates, the need for targeting and sustained delivery is still an obstacle towards safe and effective treatment. Molecular targeting with nanoparticles of liposomes is promising and so are peri-vascularly delivered polymer-based protein reservoirs. These developments will lead to future arteriogenesis strategies that are adjunct to current revascularization.

Regulation and function of miR-214 in pulmonary arterial hypertension

Dysregulation of microRNAs (miRNAs) can contribute to the etiology of diseases, including pulmonary arterial hypertension (PAH). Here we investigated a potential role for the miR-214 stem loop miRNA and the closely linked miR-199a miRNAs in PAH. All 4 miRNAs were upregulated in the lung and right ventricle (RV) in mice and rats exposed to the Sugen (SU) 5416 hypoxia model of PAH. Further, expression of the miRNAs was increased in pulmonary artery smooth muscle cells exposed to transforming growth factor β1 but not BMP4. We then examined miR-214(-/-) mice exposed to the SU 5416 hypoxia model of PAH or normoxic conditions and littermate controls. There were no changes in RV systolic pressure or remodeling observed between the miR-214(-/-) and wild-type hypoxic groups. However, we observed a significant increase in RV hypertrophy (RVH) in hypoxic miR-214(-/-) male mice compared with controls. Further, we identified that the validated miR-214 target phosphatase and tensin homolog was upregulated in miR-214(-/-) mice. Thus, miR-214 stem loop loss leads to elevated RVH and may contribute to the heart failure associated with PAH.

MEF2C-MYOCD and Leiomodin1 Suppression by miRNA-214 Promotes Smooth Muscle Cell Phenotype Switching in Pulmonary Arterial Hypertension

BACKGROUND

Vascular hyperproliferative disorders are characterized by excessive smooth muscle cell (SMC) proliferation leading to vessel remodeling and occlusion. In pulmonary arterial hypertension (PAH), SMC phenotype switching from a terminally differentiated contractile to synthetic state is gaining traction as our understanding of the disease progression improves. While maintenance of SMC contractile phenotype is reportedly orchestrated by a MEF2C-myocardin (MYOCD) interplay, little is known regarding molecular control at this nexus. Moreover, the burgeoning interest in microRNAs (miRs) provides the basis for exploring their modulation of MEF2C-MYOCD signaling, and in turn, a pro-proliferative, synthetic SMC phenotype. We hypothesized that suppression of SMC contractile phenotype in pulmonary hypertension is mediated by miR-214 via repression of the MEF2C-MYOCD-leiomodin1 (LMOD1) signaling axis.

METHODS AND RESULTS

In SMCs isolated from a PAH patient cohort and commercially obtained hPASMCs exposed to hypoxia, miR-214 expression was monitored by qRT-PCR. miR-214 was upregulated in PAH- vs. control subject hPASMCs as well as in commercially obtained hPASMCs exposed to hypoxia. These increases in miR-214 were paralleled by MEF2C, MYOCD and SMC contractile protein downregulation. Of these, LMOD1 and MEF2C were directly targeted by the miR. Mir-214 overexpression mimicked the PAH profile, downregulating MEF2C and LMOD1. AntagomiR-214 abrogated hypoxia-induced suppression of the contractile phenotype and its attendant proliferation. Anti-miR-214 also restored PAH-PASMCs to a contractile phenotype seen during vascular homeostasis.

CONCLUSIONS

Our findings illustrate a key role for miR-214 in modulation of MEF2C-MYOCD-LMOD1 signaling and suggest that an antagonist of miR-214 could mitigate SMC phenotype changes and proliferation in vascular hyperproliferative disorders including PAH.

MicroRNAs as novel therapeutic targets to treat kidney injury and fibrosis

MicroRNAs (miRs), a class of small noncoding RNAs that act as post-transcriptional regulators of gene expression, have attracted increasing attention as critical regulators of organogenesis, cancer, and disease. Interest has been spurred by development of a novel class of synthetic RNA oligonucleotides with excellent drug-like properties that hybridize to a specific miR, preventing its action. In kidney disease, a small number of miRs are dysregulated. These overlap with regulated miRs in nephrogenesis and kidney cancers. Several dysregulated miRs have been identified in fibrotic diseases of other organs, representing a "fibrotic signature," and some of these fibrotic miRs contribute remarkably to the pathogenesis of kidney disease. Chronic kidney disease, affecting ∼10% of the population, leads to kidney failure, with few treatment options. Here, we will explore the pathological mechanism of miR-21, whose pre-eminent role in amplifying kidney disease and fibrosis by suppressing mitochondrial biogenesis and function is established. Evolving roles for miR-214, -199, -200, -155, -29, -223, and -126 in kidney disease will be discussed, and we will demonstrate how studying functions of distinct miRs has led to new mechanistic insights for kidney disease progression. Finally, the utility of anti-miR oligonucleotides as potential novel therapeutics to treat chronic disease will be highlighted.

The RNA-binding protein quaking maintains endothelial barrier function and affects VE-cadherin and β-catenin protein expression

Proper regulation of endothelial cell-cell contacts is essential for physiological functioning of the endothelium. Interendothelial junctions are actively involved in the control of vascular leakage, leukocyte diapedesis, and the initiation and progression of angiogenesis. We found that the RNA-binding protein quaking is highly expressed by endothelial cells, and that its expression was augmented by prolonged culture under laminar flow and the transcription factor KLF2 binding to the promoter. Moreover, we demonstrated that quaking directly binds to the mRNA of VE-cadherin and β-catenin and can induce mRNA translation mediated by the 3′UTR of these genes. Reduced quaking levels attenuated VE-cadherin and β-catenin expression and endothelial barrier function in vitro and resulted in increased bradykinin-induced vascular leakage in vivo. Taken together, we report that quaking is essential in maintaining endothelial barrier function. Our results provide novel insight into the importance of post-transcriptional regulation in controlling vascular integrity.

A possible role of microRNAs as predictive markers for the recurrence of hepatocellular carcinoma after liver transplantation

With favourable 5-year survival rates up to 75%, liver transplantation (LT) is the treatment of choice for hepatocellular carcinoma (HCC). Nonetheless, tumour recurrence after LT remains a challenge. The aim of this retrospective study was to develop a predictive score for tumour recurrence after LT by combining clinical parameters with HCC biomarkers (microRNA). A microRNA (miRNA) microarray analysis was used to compare miRNA expression patterns in tissue samples of 40 patients with and without HCC recurrence after LT. In a screening cohort (n = 18), the miRNA analysis identified significant differences in the expression of 13 miRNAs in patients with tumour recurrence. Using the most significant miRNAs in this screening cohort, we could develop a predictive score, which combined the expression levels of miR-214, miR-3187 and the Milan criteria, and we could define low- and high-risk groups for tumour recurrence and death. The above score was evaluated in a second and independent cohort (n = 22). In contrast to the Milan criteria alone, this score was significantly associated with tumour recurrence. Our analysis indicated that the use of a specific miRNA expression pattern in combination with a limited tumour burden as defined by the Milan criteria may lead to a more accurate prediction of tumour recurrence.

Increased local delivery of antagomir therapeutics to the rodent myocardium using ultrasound and microbubbles

Recent developments in microRNA (miRNA) research have identified these as important mediators in the pathophysiological response upon myocardial infarction (MI). Specific miRNAs can inhibit the translation of entire groups of mRNAs, which are involved in specific processes in the pathophysiology after MI, e.g. the fibrotic, apoptotic or angiogenic response. By modulating miRNAs in the heart, these processes can be tuned to improve cardiac function. Antagomirs are effective miRNA-inhibitors, but have a low myocardial specificity and cardiac antagomir treatment therefore requires high doses, which causes side effects. In the present study, ultrasound-triggered microbubble destruction (UTMD) was studied to increase specific delivery of antagomir to the myocardium. Healthy control mice were treated with UTMD and sacrificed at 30min, 24h and 48h, after which antagomir delivery in the heart was analyzed, both qualitatively and quantitatively. Additionally, potential harmful effects of treatment were analyzed by monitoring ECG, analyzing neutrophil invasion and cell death in the heart, and measuring troponin I after treatment. Finally, UTMD was tested for delivery of antagomir in a model of ischemia-reperfusion (I/R) injury. We found that UTMD can significantly increase local antagomir delivery to the non-ischemic heart with modest side-effects like neutrophil invasion without causing apoptosis. Delivered antagomirs enter cardiomyocytes within 30min after treatment and remains there for at least 48h. Interestingly, after I/R injury antagomir already readily enters the infarcted zone and we observed no additional benefit of UTMD for antagomir delivery. This study is the first to explore cardiac antagomir delivery using UTMD. In addition, it is the first to study tissue distribution of short RNA based therapeutics (~22 base pairs) at both the cellular and organ levels after UTMD to the heart in general. In summary, UTMD provides a myocardial delivery strategy for non-vascular permeable cardiac conditions later in the I/R response or chronic conditions like cardiac hypertrophy.

MicroRNA-214 and MicroRNA-126 Are Potential Biomarkers for Malignant Endothelial Proliferative Diseases

Malignant endothelial proliferative diseases including human angiosarcoma (AS) and canine hemangiosarcoma (HSA) are serious diseases with a grave prognosis. Establishing liquid biopsy-based biomarkers for screening has definite clinical utility; however, plasma miRNAs up- or down-regulated in these sarcomas have been unclear. For identifying possible diagnostic plasma miRNAs for these sarcomas, we investigated whether plasma miR-214 and miR-126, which miRNAs play important roles in angiogenesis and tumorigenesis, were elevated in malignant endothelial proliferative diseases. For this investigation, human angiosarcoma and canine hemangiosarcoma cell lines and clinical plasma samples of canine hemangiosarcoma were examined by performing miRNA qRT-PCR. We report here that human angiosarcoma and canine hemangiosarcoma cell lines over-secreted miR-214 and miR-126 via microvesicles; in addition, their levels in the plasma samples from canines with hemangiosarcoma were increased. Moreover, the surgical resection of primary tumors decreased the levels of plasma miR-214 and miR-126. Our findings suggest that these malignant endothelial proliferative diseases over-secreted miR-214 and miR-126, thus suggesting that these miRNAs have potential as diagnostic biomarkers for malignant endothelial proliferative diseases in canine and possible in human angiosarcoma.

MicroRNAs; easy and potent targets in optimizing therapeutic methods in reparative angiogenesis

The age‐related senescence of adult tissues is associated with the decreased level of angiogenic capability and with the development of a degenerative disease such as atherosclerosis which thereafter result in the deteriorating function of multiple systems. Findings indicate that tissue senescence not only diminishes repair processes but also promotes atherogenesis, serving as a double‐edged sword in the development and prognosis of ischaemia‐associated diseases. Evidence evokes microRNAs (miRNAs) as molecular switchers that underlie cellular events in different tissues. Here, miRNAs would promote new potential targets for optimizing therapeutic methods in blood flow recovery to the ischaemic area. Effectively beginning an ischaemia therapy, a more characteristic of miRNA changes in adult tissues is prerequisite and in the forefront. It may also be a preliminary phase in treatment strategies by stem cell‐based therapy.

MicroRNA-214 Promotes Apoptosis in Canine Hemangiosarcoma by Targeting the COP1-p53 Axis

MicroRNA-214 regulates both angiogenic function in endothelial cells and apoptosis in various cancers. However, the regulation and function of miR-214 is unclear in canine hemangiosarcoma, which is a spontaneous model of human angiosarcoma. The expression and functional roles of miR-214 in canine hemangiosarcoma were presently explored by performing miRNA TaqMan qRT-PCR and transfecting cells with synthetic microRNA. Here, we report that miR-214 was significantly down-regulated in the cell lines used and in clinical samples of canine hemangiosarcoma. Restoration of miR-214 expression reduced cell growth and induced apoptosis in canine hemangiosarcoma cell lines through transcriptional activation of p53-regulated genes although miR-214 had a slight effect of growth inhibition on normal endothelial cells. We identified COP1, which is a critical negative regulator of p53, as a novel direct target of miR-214. COP1 was overexpressed and the specific COP1 knockdown induced apoptosis through transcriptional activation of p53-regulated genes as well as did miR-214-transfection in HSA cell lines. Furthermore, p53 knockdown abolished the miR-214-COP1-mediated apoptosis; thus, miR-214 and COP1 regulated apoptosis through controlling p53 in HSA. In conclusion, miR-214 functioned as a tumor suppressor in canine hemangiosarcoma by inducing apoptosis through recovering the function of p53. miR-214 down-regulation and COP1 overexpression is likely to contribute to tumorigenesis of HSA. Therefore, targeting miR-214-COP1-p53 axis would possibly be a novel effective strategy for treatment of canine hemangiosarcoma and capable of being applied to the development of novel therapeutics for human angiosarcoma.

MicroRNA-214 Is Upregulated in Heart Failure Patients and Suppresses XBP1-Mediated Endothelial Cells Angiogenesis

More and more miRNAs have been shown to regulate gene expression in the heart and dysregulation of their expression has been linked to cardiovascular diseases including the miR‐199a/214 cluster. However, the signature of circulating miR‐214 expression and its possible roles during the development of heart failure has been less well studied. In this study, we elucidated the biological and clinical significance of miR‐214 dysregulation in heart failure. Firstly, circulating miR‐214 was measured by quantitative PCR, and we found that miR‐214 was upregulated in the serum of chronic heart failure patients, as well as in hypertrophic and failing hearts of humans and mice. Adeno‐associated virus serotype 9 (AAV9)‐mediated miR‐214 silencing attenuates isoproterenol (ISO) infusion‐induced cardiac dysfunction and impairment of cardiac angiogenesis in mice. Mechanistically, miR‐214 overexpression reduces angiogenesis of HUVECs by targeting XBP1, an important transcription factor of unfolded protein response, and XBP1 silencing decreases HUVECs proliferation and angiogenesis similar to miR‐214 overexpression. Furthermore, ectopic expression of XBP1 enhances endothelial cells proliferation and tube formation, and reverses anti‐angiogenic effect of miR‐214 over expression. All these findings suggest that miR‐214 is an important regulator of angiogenesis in heart in vitro and in vivo, likely via regulating the expression of XBP1, and demonstrate that miR‐214 plays an essential role in the control/inhibition of cardiac angiogenesis. J. Cell. Physiol. 230: 1964–1973, 2015. © 2015 The Authors. Journal of Cellular Physiology published by Wiley Periodicals, Inc.

microRNA-340-5p Functions Downstream of Cardiotrophin-1 to Regulate Cardiac Eccentric Hypertrophy and Heart Failure via Target Gene Dystrophin

Pathological cardiac hypertrophy inevitably leads to the unfavorable outcomes of heart failure (HF) or even sudden death. microRNAs are key regulation factors participating in many pathophysiological processes. Recently, we observed upregulation of microRNA-340-5p (miR-340) in failing human hearts because of dilated cardiomyopathy, but the functional consequence of miR-340 remains to be clarified.We transfected neonatal cardiomyocytes with miR-340 and found fetal gene expression including Nppa, Nppb and Myh7. We also observed eccentric hypertrophy development upon treatment which was analogous to the phenotype after cardiotrophin-1 (CT-1) stimulation. As a potent inducer of cardiac eccentric hypertrophy, treatment by IL-6 family members CT-1 and leukemia inhibitory factor (LIF) led to the elevation of miR-340. Knockdown of miR-340 using antagomir attenuated fetal gene expression and hypertrophy formation, which means miR-340 could convey the hypertrophic signal of CT-1. To demonstrate the initial factor of miR-340 activation, we constructed a volume overloaded abdominal aorta-inferior vena cava fistula rat HF model. miR-340 and CT-1 were found to be up-regulated in the left ventricle. Dystrophin (DMD), a putative target gene of miR-340 which is eccentric hypertrophy-susceptible, was decreased in this HF model upon Western blotting and immunohistochemistry tests. Luciferase assay constructed in two seed sequence of DMD gene 3'UTR showed decreased luciferase activities, and miR-340 transfected cells resulted in the degradation of DMD.miR-340 is a pro-eccentric hypertrophy miRNA, and its expression is dependent on volume overload and cytokine CT-1 activation. Cardiomyocyte structure protein DMD is a target of miR-340.

Systemic miRNA-7 delivery inhibits tumor angiogenesis and growth in murine xenograft glioblastoma

Tumor-angiogenesis is the multi-factorial process of sprouting of endothelial cells (EC) into micro-vessels to provide tumor cells with nutrients and oxygen. To explore miRNAs as therapeutic angiogenesis-inhibitors, we performed a functional screen to identify miRNAs that are able to decrease EC viability. We identified miRNA-7 (miR-7) as a potent negative regulator of angiogenesis. Introduction of miR-7 in EC resulted in strongly reduced cell viability, tube formation, sprouting and migration. Application of miR-7 in the chick chorioallantoic membrane assay led to a profound reduction of vascularization, similar to anti-angiogenic drug sunitinib. Local administration of miR-7 in an in vivo murine neuroblastoma tumor model significantly inhibited angiogenesis and tumor growth. Finally, systemic administration of miR-7 using a novel integrin-targeted biodegradable polymeric nanoparticles that targets both EC and tumor cells, strongly reduced angiogenesis and tumor proliferation in mice with human glioblastoma xenografts. Transcriptome analysis of miR-7 transfected EC in combination with in silico target prediction resulted in the identification of OGT as novel target gene of miR-7. Our study provides a comprehensive validation of miR-7 as novel anti-angiogenic therapeutic miRNA that can be systemically delivered to both EC and tumor cells and offers promise for miR-7 as novel anti-tumor therapeutic.

The short and long of noncoding sequences in the control of vascular cell phenotypes

The two principal cell types of importance for normal vessel wall physiology are smooth muscle cells and endothelial cells. Much progress has been made over the past 20 years in the discovery and function of transcription factors that coordinate proper differentiation of these cells and the maintenance of vascular homeostasis. More recently, the converging fields of bioinformatics, genomics, and next generation sequencing have accelerated discoveries in a number of classes of noncoding sequences, including transcription factor binding sites (TFBS), microRNA genes, and long noncoding RNA genes, each of which mediates vascular cell differentiation through a variety of mechanisms. Alterations in the nucleotide sequence of key TFBS or deviations in transcription of noncoding RNA genes likely have adverse effects on normal vascular cell phenotype and function. Here, the subject of noncoding sequences that influence smooth muscle cell or endothelial cell phenotype will be summarized as will future directions to further advance our understanding of the increasingly complex molecular circuitry governing normal vascular cell differentiation and how such information might be harnessed to combat vascular diseases.

MicroRNA-132/212 family enhances arteriogenesis after hindlimb ischaemia through modulation of the Ras-MAPK pathway

Arteriogenesis is a complicated process induced by increased local shear-and radial wall-stress, leading to an increase in arterial diameter. This process is enhanced by growth factors secreted by both inflammatory and endothelial cells in response to physical stress. Although therapeutic promotion of arteriogenesis is of great interest for ischaemic diseases, little is known about the modulation of the signalling cascades via microRNAs. We observed that miR-132/212 expression was significantly upregulated after occlusion of the femoral artery. miR-132/212 knockout (KO) mice display a slower perfusion recovery after hind-limb ischaemia compared to wildtype (WT) mice. Immunohistochemical analysis demonstrates a clear trend towards smaller collateral arteries in KO mice. Although Ex vivo aortic ring assays score similar number of branches in miR-132/212 KO mice compared to WT, it can be stimulated with exogenous miR-132, a dominant member of the miR-132/212 family. Moreover, in in vitro pericyte-endothelial co-culture cell assays, overexpression of miR-132 and mir-212 in endothelial cells results in enhanced vascularization, as shown by an increase in tubular structures and junctions. Our results suggested that miR-132/212 may exert their effects by enhancing the Ras-Mitogen-activated protein kinases MAPK signalling pathway through direct inhibition of Rasa1, and Spred1. The miR-132/212 cluster promotes arteriogenesis by modulating Ras-MAPK signalling via direct targeting of its inhibitors Rasa1 and Spred1.

MicroRNA-155 Exerts Cell-Specific Antiangiogenic but Proarteriogenic Effects During Adaptive Neovascularization

BACKGROUND

Adaptive neovascularization after arterial occlusion is an important compensatory mechanism in cardiovascular disease and includes both the remodeling of pre-existing vessels to collateral arteries (arteriogenesis) and angiogenic capillary growth. We now aimed to identify regulatory microRNAs involved in the modulation of neovascularization after femoral artery occlusion in mice.

METHODS AND RESULTS

Using microRNA-transcriptome analysis, we identified miR-155 as a downregulated microRNA during hindlimb ischemia. Correspondingly, inhibition of miR-155 in endothelial cells had a stimulatory effect on proliferation and angiogenic tube formation via derepression of its direct target gene angiotensin II type 1 receptor. Surprisingly, miR-155-deficient mice showed an unexpected phenotype in vivo, with a strong reduction of blood flow recovery after femoral artery ligation (arteriogenesis) dependent on the attenuation of leukocyte-endothelial interaction and a reduction of proarteriogenic cytokine expression. Consistently, miR-155-deficient macrophages exhibit a specific alteration of the proarteriogenic cytokine expression profile, which is partly mediated by the direct miR-155 target gene SOCS-1.

CONCLUSIONS

Our data demonstrate that miR-155 exerts an antiangiogenic but proarteriogenic function in the regulation of neovascularization via the suppression of divergent cell-specific target genes and that its expression in both endothelial and bone marrow-derived cells is essential for arteriogenesis in response to hindlimb ischemia in mice.

Angiogenesis-regulating microRNAs and Ischemic Stroke

Stroke is a leading cause of death and disability worldwide. Ischemic stroke is the dominant subtype of stroke and results from focal cerebral ischemia due to occlusion of major cerebral arteries. Thus, the restoration or improvement of reduced regional cerebral blood supply in a timely manner is very critical for improving stroke outcomes and poststroke functional recovery. The recovery from ischemic stroke largely relies on appropriate restoration of blood flow via angiogenesis. Newly formed vessels would allow increased cerebral blood flow, thus increasing the amount of oxygen and nutrients delivered to affected brain tissue. Angiogenesis is strictly controlled by many key angiogenic factors in the central nervous system, and these molecules have been well-documented to play an important role in the development of angiogenesis in response to various pathological conditions. Promoting angiogenesis via various approaches that target angiogenic factors appears to be a useful treatment for experimental ischemic stroke. Most recently, microRNAs (miRs) have been identified as negative regulators of gene expression in a post-transcriptional manner. Accumulating studies have demonstrated that miRs are essential determinants of vascular endothelial cell biology/angiogenesis as well as contributors to stroke pathogenesis. In this review, we summarize the knowledge of stroke-associated angiogenic modulators, as well as the role and molecular mechanisms of stroke-associated miRs with a focus on angiogenesis-regulating miRs. Moreover, we further discuss their potential impact on miR-based therapeutics in stroke through targeting and enhancing post-ischemic angiogenesis.

Ultrasound and microbubble-induced local delivery of MicroRNA-based therapeutics

MicroRNAs are involved in many pathologic processes and are a promising target for therapeutic intervention. However, successful, localized delivery of microRNA-based therapeutics is lacking. In this study, cationic ultrasound-responsive microbubbles (MBs) were used to deliver microRNA blockers and mimics in vitro and in vivo. Cationic MBs successfully delivered microRNA blockers to human endothelial cells on ultrasound (US) exposure in vitro. This in vitro US protocol did not successfully deliver microRNA mimics to skeletal muscle of mice, whereas an US protocol that is routinely used for contrast imaging did. Additionally, we used cationic MBs and US to locally deliver antimiR and antagomiR molecules with US causing inertial cavitation. Delivery of antimiR to the extracellular compartments of the muscle was only slightly increased, whereas delivery of antagomiR to the capillaries, myocytes and extracellular space was significantly increased. AntagomiR seems to be a more suitable microRNA blocker than antimiR for use in combination with MBs and US for local delivery.

MicroRNAs in colorectal cancer: small molecules with big functions

Colorectal cancer (CRC) is the third most lethal malignancy, with pathogenesis intricately dependent upon microRNAs (miRNAs). miRNAs are short, non-protein coding RNAs, targeting the 3'-untranslated regions (3'-UTR) of certain mRNAs. They usually serve as tumor suppressors or oncogenes, and participate in tumor phenotype maintenance. Therefore, miRNAs consequently regulate CRC carcinogenesis and other biological functions, including apoptosis, development, angiogenesis, migration, and proliferation. Due to its differential expression and distinct stability, miRNAs are regarded as molecular biomarkers (for diagnosis/prognosis) and therapeutic targets for CRC. Recently, a remarkable number of miRNAs have been discovered with implications via incompletely understood mechanisms in CRC. As further study of relevant miRNAs continues, it is hopeful that novel miRNA-based therapeutic strategies may be available for CRC patients in the future.

miR-214 as a key hub that controls cancer networks: small player, multiple functions

MicroRNAs are short regulatory RNAs that are able to post-transcriptionally modulate gene expression and that have crucial roles in the control of physiological and pathological processes including cancer onset, growth, and progression. miR-214, located inside the sequence of the long noncoding Dmn3os transcript, contributes to the regulation of normal and cancer cell biology, even if it operates in a context-dependent and sometimes contradictory manner. miR-214 is deregulated in several human tumors including melanoma, breast, ovarian, gastric, and hepatocellular carcinomas. miR-214's pleiotropic and tumor-specific contribution to various cancer formation and progression hallmarks is achieved via its several target genes. In fact, miR-214 behaves as a key hub by coordinating fundamental signaling networks such as PTEN/AKT, β-catenin, and tyrosine kinase receptor pathways. Interestingly, miR-214 also regulates the levels of crucial gene expression modulators: the epigenetic repressor Ezh2, "genome guardian" p53, transcription factors TFAP2, and another microRNA, miR-148b. Thus, miR-214 seems to have essential roles in coordinating tumor proliferation, stemness, angiogenesis, invasiveness, extravasation, metastasis, resistance to chemotherapy, and microenvironment. The sum of current literature reports suggests that miR-214 is a molecular hub involved in the control of cancer networks and, as such, could be a potential diagnostic/prognostic biomarker and target for therapeutic intervention.

miR-125a-5p impairs endothelial cell angiogenesis in aging mice via RTEF-1 downregulation

Increasing evidence suggests that microRNAs (miRNAs) play important roles in impaired endothelial cell (EC) angiogenesis during aging. However, their exact roles in the aging process remain unclear. We aimed to determine whether miRNAs cause angiogenesis defects in ECs during aging and to uncover the underlying mechanisms. To study the miRNA-induced changes in ECs during aging, we performed microarray analyses on arterial ECs collected from young and aging mice. Using qRT–PCR, we showed that microRNA-125a-5p (mir-125a-5p) expression was approximately 2.9 times higher in old endothelial cells (OECs) compared with samples collected from young animals. Western blot assays showed a lower expression level of an mir-125a-5p target known as related transcriptional enhancer factor-1 (RTEF-1) in OECs compared with its expression levels in young cells. Overexpression of mir-125a-5p in young endothelial cells (YECs) using pre-mir-125a-5p caused the downregulation of RTEF-1, endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) and resulted in impaired angiogenesis, as evidenced by spheroid sprouting and tube formation assays in vitro. Conversely, repression of mir-125a-5p in OECs using anti-mir-125a-5p increased RTEF-1, eNOS and VEGF expression and improved EC angiogenesis. Importantly, impaired angiogenesis caused by knock-down of RTEF-1 was not efficiently rescued by anti-mir-125a-5p. Dual-luciferase reporter gene analysis showed that RTEF-1 is a direct target of mir-125a-5p, which regulates angiogenesis by repressing RTEF-1 expression and modulating eNOS and VEGF expression. These findings indicate that mir-125a-5p and RTEF-1 are potential therapeutic targets for improving EC-mediated angiogenesis in elderly individuals.

Transglutaminase II/microRNA-218/-181a loop regulates positive feedback relationship between allergic inflammation and tumor metastasis

The molecular mechanism of transglutaminase II (TGaseII)-mediated allergic inflammation remains largely unknown. TGaseII, induced by antigen stimulation, showed an interaction and co-localization with FcϵRI. TGaseII was necessary for in vivo allergic inflammation, such as triphasic cutaneous reaction, passive cutaneous anaphylaxis, and passive systemic anaphylaxis. TGaseII was necessary for the enhanced metastatic potential of B16F1 melanoma cells by passive systemic anaphylaxis. TGaseII was shown to be a secreted protein. Recombinant TGaseII protein increased the histamine release and β-hexosaminidase activity, and enhanced the metastatic potential of B16F1 mouse melanoma cells. Recombinant TGaseII protein induced the activation of EGF receptor and an interaction between EGF receptor and FcϵRI. Recombinant TGaseII protein displayed angiogenic potential accompanied by allergic inflammation. R2 peptide, an inhibitor of TGaseII, exerted negative effects on in vitro and in vivo allergic inflammation by regulating the expression of TGaseII and FcϵRI signaling. MicroRNA (miR)-218 and miR-181a, decreased during allergic inflammation, were predicted as negative regulators of TGaseII by microRNA array and TargetScan analysis. miR-218 and miR-181a formed a negative feedback loop with TGaseII and regulated the in vitro and in vivo allergic inflammation. TGaseII was necessary for the interaction between mast cells and macrophages during allergic inflammation. Mast cells and macrophages, activated during allergic inflammation, were responsible for the enhanced metastatic potential of tumor cells that are accompanied by allergic inflammation. In conclusion, the TGaseII/miR-218/-181a feedback loop can be employed for the development of anti-allergy therapeutics.

MicroRNAs: promising new antiangiogenic targets in cancer

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.

Targeted delivery of miRNA therapeutics for cardiovascular diseases: opportunities and challenges

Dysregulation of miRNA expression has been associated with many cardiovascular diseases in animal models, as well as in patients. In the present review, we summarize recent findings on the role of miRNAs in cardiovascular diseases and discuss the opportunities, possibilities and challenges of using miRNAs as future therapeutic targets. Furthermore, we focus on the different approaches that can be used to deliver these newly developed miRNA therapeutics to their sites of action. Since siRNAs are structurally homologous with the miRNA therapeutics, important lessons learned from siRNA delivery strategies are discussed that might be applicable to targeted delivery of miRNA therapeutics, thereby reducing costs and potential side effects, and improving efficacy.

MicroRNAs in myocardial ischemia: identifying new targets and tools for treating heart disease. New frontiers for miR-medicine

MicroRNAs (miRNAs) are natural, single-stranded, small RNA molecules which subtly control gene expression. Several studies indicate that specific miRNAs can regulate heart function both in development and disease. Despite prevention programs and new therapeutic agents, cardiovascular disease remains the main cause of death in developed countries. The elevated number of heart failure episodes is mostly due to myocardial infarction (MI). An increasing number of studies have been carried out reporting changes in miRNAs gene expression and exploring their role in MI and heart failure. In this review, we furnish a critical analysis of where the frontier of knowledge has arrived in the fields of basic and translational research on miRNAs in cardiac ischemia. We first summarize the basal information on miRNA biology and regulation, especially concentrating on the feedback loops which control cardiac-enriched miRNAs. A focus on the role of miRNAs in the pathogenesis of myocardial ischemia and in the attenuation of injury is presented. Particular attention is given to cardiomyocyte death (apoptosis and necrosis), fibrosis, neovascularization, and heart failure. Then, we address the potential of miR-diagnosis (miRNAs as disease biomarkers) and miR-drugs (miRNAs as therapeutic targets) for cardiac ischemia and heart failure. Finally, we evaluate the use of miRNAs in the emerging field of regenerative medicine.

CS5931, a novel polypeptide in Ciona savignyi, represses angiogenesis via inhibiting vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs)

CS5931 is a novel polypeptide from Cionasavignyi with anticancer activities. Previous study in our laboratory has shown that CS5931 can induce cell death via mitochondrial apoptotic pathway. In the present study, we found that the polypeptide could inhibit angiogenesis both in vitro and in vivo. CS5931 inhibited the proliferation, migration and formation of capillary-like structures of HUVECs (Human Umbilical Vein Endothelial Cell) in a dose-dependent manner. Additionally, CS5931 repressed spontaneous angiogenesis of the zebrafish vessels. Further studies showed that CS5931 also blocked vascular endothelial growth factor (VEGF) production but without any effect on its mRNA expression. Moreover, CS5931 reduced the expression of matrix metalloproteinases (MMP-2 and MMP-9) both on protein and mRNA levels in HUVEC cells. We demonstrated that CS5931 possessed strong anti-angiogenic activity both in vitro and in vivo, possible via VEGF and MMPs. This study indicates that CS5931 has the potential to be developed as a novel therapeutic agent as an inhibitor of angiogenesis for the treatment of cancer.

MicroRNA signature and function in retinal neovascularization

Ischemic retinopathies are clinically well-defined chronic microvascular complications characterized by gradually progressive alterations in the retinal microvasculature and a compensatory aberrant neovascularization of the eye. The subsequent metabolic deficiencies result in structural and functional alterations in the retina which is highly susceptible to injurious stimuli such as diabetes, trauma, hyperoxia, inflammation, aging and dysplipidemia. Emerging evidence indicates that an effective therapy may require targeting multiple components of the angiogenic pathway. Conceptually, mircoRNA (miRNA)-based therapy provides the rationale basis for an effective antiangiogenic treatment. miRNAs are an evolutionarily conserved family of short RNAs, each regulating the expression of multiple protein-coding genes. The activity of specific miRNAs is important for vascular cell signaling and blood vessel formation and function. Recently, important progress has been made in mapping the miRNA-gene target network and miRNA-mediated gene expression control. Here we highlight the latest findings on angiogenic and antiangiogenic miRNAs and their targets as well as potential implications in ocular neovascular diseases. Emphasis is placed on how specific vascular-enriched miRNAs regulate cell responses to various cues by targeting several factors, receptors and/or signaling molecules in order to maintain either vascular function or dysfunction. Further improvement of our knowledge in not only miRNA specificity, turnover, and transport but also how miRNA sequences and functions can be altered will enhance the therapeutic utility of such molecules.

Prediction value of miR-483 and miR-214 in prognosis and multidrug resistance of esophageal squamous cell carcinoma

BACKGROUND AND AIMS

Here, we have investigated the role of miR-483 and miR-214 in the prognosis and multidrug resistance (MDR) of esophageal squamous cell carcinoma.

METHODS

The expression of miR-483 and miR-214 was detected in 104 cases of esophageal cancer tissues and matched adjacent benign esophageal tissues by quantitative real-time PCR. The relation of microRNA expression with survival was statistically analyzed. The roles of miR-483 and miR-214 in MDR of esophageal squamous cell cancer cells were further evaluated.

RESULTS

The expression of miR-483 and miR-214 was found significantly upregulated in esophageal squamous cell cancer tissues. The expression levels of miR-483 and miR-214 showed an inverse correlation with overall survival. High expression of miR-483 and miR-214 might predict less chemotherapy effect. Downregulation of miR-483 and miR-214 could confer sensitivity of both P-glycoprotein-related and P-glycoprotein-nonrelated drugs to esophageal cancer cells, and it might induce increased accumulation of adriamycin (ADR) and decreased amount of ADR released.

CONCLUSIONS

miR-483 and miR-214 might play important roles in the pathogenesis of esophageal cancer and should be considered as potential targets for intervention in this malignancy.

Post-transcriptional regulation of α-1-antichymotrypsin by microRNA-137 in chronic heart failure and mechanical support

BACKGROUND

Better understanding of the molecular mechanisms of remodeling has become a major objective of heart failure (HF) research to stop or reverse its progression. Left ventricular assist devices (LVADs) are being used in patients with HF, leading to partial reverse remodeling. In the present study, proteomics identified significant changes in α-1-antichymotrypsin (ACT) levels during LVAD support. Moreover, the potential role of ACT in reverse remodeling was studied in detail.

METHODS AND RESULTS

Expression of ACT mRNA (quantitative-polymerase chain reaction) decreased significantly in post-LVAD myocardial tissue compared with pre-LVAD tissue (n=15; P<0.01). Immunohistochemistry revealed that ACT expression and localization changed during LVAD support. Circulating ACT levels were elevated in HF patients (n=18) as compared with healthy controls (n=6; P=0.001) and normalized by 6 months of LVAD support. Because increasing evidence implicates that microRNAs (miRs) are involved in myocardial disease processes, we also investigated whether ACT is post-transcriptionally regulated by miRs. Bioinformatics analysis pointed miR-137 as a potential regulator of ACT. The miR-137 expression is inversely correlated with ACT mRNA in myocardial tissue. Luciferase activity assays confirmed ACT as a direct target for miR-137, and in situ hybridization indicated that ACT and miR-137 were mainly localized in cardiomyocytes and stromal cells.

CONCLUSIONS

High ACT plasma levels in HF normalized during LVAD support, which coincides with decreased ACT mRNA in heart tissue, whereas miR-137 levels increased. MiR-137 directly targeted ACT, thereby indicating that ACT and miR-137 play a role in the pathophysiology of HF and reverse remodeling during mechanical support.

Quaking and PTB control overlapping splicing regulatory networks during muscle cell differentiation

Alternative splicing contributes to muscle development, but a complete set of muscle-splicing factors and their combinatorial interactions are unknown. Previous work identified ACUAA ("STAR" motif) as an enriched intron sequence near muscle-specific alternative exons such as Capzb exon 9. Mass spectrometry of myoblast proteins selected by the Capzb exon 9 intron via RNA affinity chromatography identifies Quaking (QK), a protein known to regulate mRNA function through ACUAA motifs in 3' UTRs. We find that QK promotes inclusion of Capzb exon 9 in opposition to repression by polypyrimidine tract-binding protein (PTB). QK depletion alters inclusion of 406 cassette exons whose adjacent intron sequences are also enriched in ACUAA motifs. During differentiation of myoblasts to myotubes, QK levels increase two- to threefold, suggesting a mechanism for QK-responsive exon regulation. Combined analysis of the PTB- and QK-splicing regulatory networks during myogenesis suggests that 39% of regulated exons are under the control of one or both of these splicing factors. This work provides the first evidence that QK is a global regulator of splicing during muscle development in vertebrates and shows how overlapping splicing regulatory networks contribute to gene expression programs during differentiation.

miR-574-5p negatively regulates Qki6/7 to impact β-catenin/Wnt signalling and the development of colorectal cancer

OBJECTIVE

Deficiency or reduced expression of signal transduction and activation of RNA family protein Quaking (Qki) is associated with developmental defects in neural and vascular tissues and the development of debilitating human diseases including colorectal cancer (CRC). However, the mechanisms underlying the aberrant downregulation or deficiency of Qki were uncertain.

DESIGN

Expression of miR-574-5p, Qki5/6/7/7b splicing variants, β-catenin and p27(Kip1) was determined in mouse and human CRC cells and tissues to investigate the post-transcriptional regulation of Qki isoforms by miR-574-5p and its impact on β-catenin/p27(Kip1) signalling, cell cycle progression, proliferation, migration, invasion and tumour growth.

RESULTS

In the CRC tissues of C57BL/6-Apc(min/+) mice, miR-574-5p was found to be significantly upregulated and negatively correlated with the expression of Qki but positively correlated with the expression of β-catenin. In mouse and human CRC cells, miR-574-5p was shown to regulate Qki isoforms (Qki6/7 in particular) post-transcriptionally and caused altered expression in β-catenin and p27(Kip1) , increased proliferation, migration and invasion and decreased differentiation and cell cycle exit. Furthermore, in clinical CRC tissues, miR-574-5p was shown to be greatly upregulated and inversely correlated with the expression of Qkis. Finally, inhibition of miR-574-5p was shown to suppress the growth of tumours in the nude mice.

CONCLUSIONS

Together, these novel findings suggest that miR-574-5p is a potent ribo-regulator for Qkis and that aberrant miR-574-5p upregulation can be oncogenic.

Increasing short-term cardiomyocyte progenitor cell (CMPC) survival by necrostatin-1 did not further preserve cardiac function

AIMS

One of the main limitations for an effective cell therapy for the heart is the poor cell engraftment after implantation, which is partly due to a large percentage of cell death in the hostile myocardium. In the present study, we investigated the utilization of necrostatin-1 (Nec-1) as a possible attenuator of cell death in cardiomyocyte progenitor cells (CMPCs).

METHODS AND RESULTS

In a mouse model of myocardial infarction, survival of CMPCs 3 days after intra-myocardial injection was 39 ± 9% higher in cells pretreated with the Nec-1 compound. However, the increase in cell number was not sustained over 28 days, and did not translate into improved cardiac function (ejection fraction %, 20.6 ± 2.1 vs. 21.4 ± 2.5 for vehicle and Nec-1-treated CMPC, respectively). Nonetheless, Nec-1 rescued CMPCs remained functionally competent.

CONCLUSION

A pharmacological pretreatment approach to solely enhance cell survival on the short term does not seem to be effective strategy to improve cardiac cell therapy with CMPCs.

Endothelial cells require miR-214 to secrete exosomes that suppress senescence and induce angiogenesis in human and mouse endothelial cells

Signaling between endothelial cells, endothelial progenitor cells, and stromal cells is crucial for the establishment and maintenance of vascular integrity and involves exosomes, among other signaling pathways. Exosomes are important mediators of intercellular communication in immune signaling, tumor survival, stress responses, and angiogenesis. The ability of exosomes to incorporate and transfer messenger RNAs (mRNAs) encoding for "acquired" proteins or micro RNAs (miRNAs) repressing "resident" mRNA translation suggests that they can influence the physiological behavior of recipient cells. We demonstrate that miR-214, an miRNA that controls endothelial cell function and angiogenesis, plays a dominant role in exosome-mediated signaling between endothelial cells. Endothelial cell-derived exosomes stimulated migration and angiogenesis in recipient cells, whereas exosomes from miR-214-depleted endothelial cells failed to stimulate these processes. Exosomes containing miR-214 repressed the expression of ataxia telangiectasia mutated in recipient cells, thereby preventing senescence and allowing blood vessel formation. Concordantly, specific reduction of miR-214 content in exosome-producing endothelial cells abolishes the angiogenesis stimulatory function of the resulting exosomes. Collectively, our data indicate that endothelial cells release miR-214-containing exosomes to stimulate angiogenesis through the silencing of ataxia telangiectasia mutated in neighboring target cells.

Preparation and characterizations of polyclonal antibodies against STAR protein QKI7b

Quaking (QKI) proteins are important regulators of RNA metabolism and cellular signal transduction. Recent studies have shown that isoforms of QKI proteins, which include QKI5/6/7/7b in human cells, play important roles in the development of neurological diseases and human cancers. In comparison with QKI5/6/7, however, there are little data on QKI7b due to lack of specific antibodies. Here, we reported the preparation and initial characterizations of polyclonal antibodies against human QKI7b. Utilizing a chemically synthesized C-terminal peptide fragment of human QKI7b, we raised two preparations of rabbit antiserum. We found that these antibodies were able to recognize human QKI7b, but not QKI5/6/7. Our immunofluorescence staining showed that in LO2 hepatocytes, QKI7b localizes predominantly in the perinuclear cytoplasm and less abundantly in the nucleus. In clinical samples, we showed that like QKI5/6/7 proteins, QKI7b protein was also significantly downregulated in most human colorectal cancer tissues. These antibodies, therefore, might be useful in future functional studies of QKI7b.

Transforming growth factor β-regulated microRNA-29a promotes angiogenesis through targeting the phosphatase and tensin homolog in endothelium

The TGF-β pathway plays an important role in physiological and pathological angiogenesis. MicroRNAs (miRNAs) are a class of 18- to 25-nucleotide, small, noncoding RNAs that function by regulating gene expression. A number of miRNAs have been found to be regulated by the TGF-β pathway. However, the role of endothelial miRNAs in the TGF-β-mediated control of angiogenesis is still largely unknown. Here we investigated the regulation of endothelial microRNA-29a (miR-29a) by TGF-β signaling and the potential role of miR-29a in angiogenesis. MiR-29a was directly up-regulated by TGF-β/Smad4 signaling in human and mice endothelial cells. In a chick chorioallantoic membrane assay, miR-29a overexpression promoted the formation of new blood vessels, and miR-29a suppression completely blocked TGF-β1-stimulated angiogenesis. Consistently, miR-29a overexpression increased tube formation and migration in endothelial cultures. Mechanistically, miR-29a directly targeted the phosphatase and tensin homolog (PTEN) in endothelial cells, leading to activation of the AKT pathway. PTEN knockdown recapitulated the role of miR-29a in endothelial migration, whereas AKT inhibition completely attenuated the stimulating role of miR-29a in angiogenesis. Taken together, these results reveal a crucial role of a TGF-β-regulated miRNA in promoting angiogenesis by targeting PTEN to stimulate AKT activity.

MicroRNAs in Myocardial Infarction

The complexity of posttranscriptional regulation by noncoding microRNAs (miRNAs, miRs) is still not completely understood. A large fraction of the genome is under the control of miRs via (partial) complementary base pairing within the corresponding mRNA region. Myocardial infarction is characterized by strongly altered gene expression, deregulation of underlying signaling pathways, and crucial participation of several miRs in this context. Mechanistically, miR induction or repression after myocardial infarction triggers downstream events in a cell-type–specific manner, and interference with endogenous miR expression might regulate overall cardiac function. In this brief review, we (1) summarize the current knowledge about the importance of several miRs after myocardial infarction, (2) report about novel miR-based therapeutic approaches to counteract maladaptive remodeling upon cardiac ischemia, and (3) discuss briefly the use of miRs as biomarkers for cardiac ischemia.