MicroRNA control of vascular endothelial growth factor signaling output during vascular development

Acute Effects of Serial and Integrated Concurrent Exercise on Circulating microRNAs -126 and -222 in Sedentary Adults

The purpose of this study was to compare changes in circulating microRNAs -126 (c-miR-126) and -222 (c-miR-222) following acute serial concurrent exercise (SCE) and integrated concurrent exercise (ICE) sessions among young, sedentary adults. Ten males and 9 females completed the study procedures. For SCE, participants performed resistance exercise (RE) followed by aerobic exercise (AE), without mixing the two. For ICE, participants performed a brief bout of AE before each set of RE. Blood was collected before, immediately after (IP), and 1 h (1HR) after each exercise session. Expression of c-miR-126 significantly increased from baseline at IP (1.6-fold SCE, 2.1-fold ICE; p = .037) and 1HR (1.8-fold SCE, 1.7-fold ICE; p = .034) following both sessions, with no difference between the two sessions. Expression of c-miR-222 significantly increased from baseline at IP (1.7-fold SCE, 1.9-fold ICE; p = .024) and 1HR (2.0-fold SCE, 1.6-fold ICE; p = .038) following both sessions, with no difference between the two sessions. There were no differences in peak heart rate or average heart rate between the two workout sessions. Both SCE and ICE patterns appear equally effective at acutely increasing c-miR-126 and -222.

Cold water immersion in recovery following a single bout resistance exercise suppresses mechanisms of miRNA nuclear export and maturation

Cold water immersion (CWI) following intense exercise is a common athletic recovery practice. However, CWI impacts muscle adaptations to exercise training, with attenuated muscle hypertrophy and increased angiogenesis. Tissue temperature modulates the abundance of specific miRNA species and thus CWI may affect muscle adaptations via modulating miRNA expression following a bout of exercise. The current study focused on the regulatory mechanisms involved in cleavage and nuclear export of mature miRNA, including DROSHA, EXPORTIN-5, and DICER. Muscle biopsies were obtained from the vastus lateralis of young males (n = 9) at rest and at 2, 4, and 48 h of recovery from an acute bout of resistance exercise, followed by either 10 min of active recovery (ACT) at ambient temperature or CWI at 10°C. The abundance of key miRNA species in the regulation of intracellular anabolic signaling (miR-1 and miR-133a) and angiogenesis (miR-15a and miR-126) were measured, along with several gene targets implicated in satellite cell dynamics (NCAM and PAX7) and angiogenesis (VEGF and SPRED-1). When compared to ACT, CWI suppressed mRNA expression of DROSHA (24 h p = 0.025 and 48 h p = 0.017), EXPORTIN-5 (24 h p = 0.008), and DICER (24 h p = 0.0034). Of the analyzed miRNA species, miR-133a (24 h p < 0.001 and 48 h p = 0.007) and miR-126 (24 h p < 0.001 and 48 h p < 0.001) remained elevated at 24 h post-exercise in the CWI trial only. Potential gene targets of these miRNA, however, did not differ between trials. CWI may therefore impact miRNA abundance in skeletal muscle, although the precise physiological relevance needs further investigation.

VEGFR3 suppression through miR-1236 inhibits proliferation and induces apoptosis in ovarian cancer via ERK1/2 and AKT signaling pathways

Vascular endothelial growth factor receptor 3 (VEGFR3) is expressed in cancer cell lines and exerts a critical role in cancer progression. However, the signaling pathways of VEGFR3 in ovarian cancer cell proliferation remain unclear. This study aimed to demonstrate the signaling pathways of VEGFR3 through the upregulated expression of miR-1236 in ovarian cancer cells. We found that the messenger RNA and protein of VEGFR3 were expressed in the ovarian cancer cell lines, but downregulated after microRNA-1236 (miR-1236) transfection. The inhibition of VEGFR3, using miR-1236, significantly reduced cell proliferation, clonogenic survival, migration, and invasion ability in SKOV3 and OVCAR3 cells (p < 0.01). The flow cytometry results indicated that the rate of apoptotic cells in SKOV3 (38.65%) and OVCAR3 (41.95%) cells increased following VEGFR3 inhibition. Moreover, VEGFR3 stimulation (using a specific ligand, VEGF-CS) significantly increased extracellular signal-regulated kinase 1/2 (ERK1/2) and protein kinase B (AKT) phosphorylation (p < 0.01), whereas VEGFR3 suppression reduced p-ERK1/2 (67.94% in SKOV3 and 93.52% in OVCAR3) and p-AKT (59.56% in SKOV3 and 78.73% in OVCAR3) compared to the VEGF-CS treated group. This finding demonstrated that miR-1236 may act as an endogenous regulator of ERK1/2 and AKT signaling by blocking the upstream regulator of VEGFR3. Overall, we demonstrated the important role of the miR-1236/VEGFR3 axis in ovarian cancer cell proliferation by regulating the ERK1/2 and AKT signaling that might be an effective strategy against ovarian cancer.

Molecular and genetic mechanisms in brain arteriovenous malformations: new insights and future perspectives

Brain arteriovenous malformations (bAVMs) are rare vascular lesions made of shunts between cerebral arteries and veins without the interposition of a capillary bed. The majority of bAVMs are asymptomatic, but some may be revealed by seizures and potentially life-threatening brain hemorrhage. The management of unruptured bAVMs remains a matter of debate. Significant progress in the understanding of their pathogenesis has been made during the last decade, particularly using genome sequencing and biomolecular analysis. Herein, we comprehensively review the recent molecular and genetic advances in the study of bAVMs that not only allow a better understanding of the genesis and growth of bAVMs, but also open new insights in medical treatment perspectives.

Dissecting miRNA–Gene Networks to Map Clinical Utility Roads of Pharmacogenomics-Guided Therapeutic Decisions in Cardiovascular Precision Medicine

MicroRNAs (miRNAs) create systems networks and gene-expression circuits through molecular signaling and cell interactions that contribute to health imbalance and the emergence of cardiovascular disorders (CVDs). Because the clinical phenotypes of CVD patients present a diversity in their pathophysiology and heterogeneity at the molecular level, it is essential to establish genomic signatures to delineate multifactorial correlations, and to unveil the variability seen in therapeutic intervention outcomes. The clinically validated miRNA biomarkers, along with the relevant SNPs identified, have to be suitably implemented in the clinical setting in order to enhance patient stratification capacity, to contribute to a better understanding of the underlying pathophysiological mechanisms, to guide the selection of innovative therapeutic schemes, and to identify innovative drugs and delivery systems. In this article, the miRNA–gene networks and the genomic signatures resulting from the SNPs will be analyzed as a method of highlighting specific gene-signaling circuits as sources of molecular knowledge which is relevant to CVDs. In concordance with this concept, and as a case study, the design of the clinical trial GESS (NCT03150680) is referenced. The latter is presented in a manner to provide a direction for the improvement of the implementation of pharmacogenomics and precision cardiovascular medicine trials.

Decreased Levels of miR-126 and miR-132 in Plasma and Vitreous Humor of Non-Proliferative Diabetic Retinopathy Among Subjects with Type-2 Diabetes Mellitus

PURPOSE

Diabetic retinopathy (DR), the leading cause of blindness among working adults, is an urgent public health problem as diabetes mellitus (DM) is increasing at an alarming rate. Hyperglycemia-induced endothelial dysfunction is the principal contributing factor leading to the development of microangiopathy. Altered levels of microRNA (miR), the negative regulator of protein-coding genes, have been observed and considered to be markers for DR. Present study aimed to find out whether miR levels in plasma could be effective biomarkers to differentiate between type 2 diabetes mellitus (T2DM) with non-proliferative retinopathy (NPDR) from T2DM with no-DR (DNR).

METHODS

We recruited 50 T2DM subjects comprising 31 NPDR and 19 DNR individuals. Surrogate markers of systemic oxidative stress and vascular endothelial growth factor (VEGF) were measured in plasma. Levels of miR-126 and miR-132 were determined in plasma and vitreous fluid using real-time PCR.

RESULTS

We observed that levels of miR-126 and miR-132 were decreased in NPDR subjects in comparison to DNR. Plasma levels of miRs were inversely correlated with secreted levels of VEGF and oxidative stress marker. The levels of these miRs showed discriminating ability between NPDR and DNR.

CONCLUSION

Circulating miRs 126 and 132 in plasma or vitreous may serve as biomarkers for early diabetic retinopathy risk prediction, provided validated in a larger cohort and other forms of retinal vasculopathy or retinopathy in the future.

Extracellular vesicles synchronize cellular phenotypes of differentiating cells

During embryonic development, cells differentiate in a coordinated manner, aligning their fate decisions and differentiation stages with those of surrounding cells. However, little is known about the mechanisms that regulate this synchrony. Here we show that cells in close proximity synchronize their differentiation stages and cellular phenotypes with each other via extracellular vesicle (EV)-mediated cellular communication. We previously established a mouse embryonic stem cell (ESC) line harbouring an inducible constitutively active protein kinase A (CA-PKA) gene and found that the ESCs rapidly differentiated into mesoderm after PKA activation. In the present study, we performed a co-culture of Control-ESCs and PKA-ESCs, finding that both ESC types rapidly differentiated in synchrony even when PKA was activated only in PKA-ESCs, a phenomenon we named 'Phenotypic Synchrony of Cells (PSyC)'. We further demonstrated PSyC was mediated by EVs containing miR-132. PKA-ESC-derived EVs and miR-132-containing artificial nano-vesicles similarly enhanced mesoderm and cardiomyocyte differentiation in ESCs and ex vivo embryos, respectively. PSyC is a new form of cell-cell communication mediated by the EV regulation of neighbouring cells and could be broadly involved in tissue development and homeostasis.

TFEB Signalling-Related MicroRNAs and Autophagy

The oncogenic Transcription Factor EB (TFEB), a member of MITF-TFE family, is known to be the most important regulator of the transcription of genes responsible for the control of lysosomal biogenesis and functions, autophagy, and vesicles flux. TFEB activation occurs in response to stress factors such as nutrient and growth factor deficiency, hypoxia, lysosomal stress, and mitochondrial damage. To reach the final functional status, TFEB is regulated in multimodal ways, including transcriptional rate, post-transcriptional regulation, and post-translational modifications. Post-transcriptional regulation is in part mediated by miRNAs. miRNAs have been linked to many cellular processes involved both in physiology and pathology, such as cell migration, proliferation, differentiation, and apoptosis. miRNAs also play a significant role in autophagy, which exerts a crucial role in cell behaviour during stress or survival responses. In particular, several miRNAs directly recognise TFEB transcript or indirectly regulate its function by targeting accessory molecules or enzymes involved in its post-translational modifications. Moreover, the transcriptional programs triggered by TFEB may be influenced by the miRNA-mediated regulation of TFEB targets. Finally, recent important studies indicate that the transcription of many miRNAs is regulated by TFEB itself. In this review, we describe the interplay between miRNAs with TFEB and focus on how these types of crosstalk affect TFEB activation and cellular functions.

A Feedback Loop Involving MicroRNA-150 and MYB Regulates VEGF Expression in Brain Microvascular Endothelial Cells After Oxygen Glucose Deprivation

Vascular endothelial growth factor (VEGF) plays a pivotal role in regulating cerebral angiogenesis after stroke. Meanwhile, excessive VEGF expression induces increased microvascular permeability in brain, probably leading to neurological deterioration. Therefore, the appropriate level of VEGF expression is significant to the recovery of brain exposed to stroke. In this work, we demonstrate that microRNA-150 (miR-150) and its predicted target MYB form a negative feedback loop to control the level of post-stroke VEGF expression. Repression of MYB leads to decreased expression of miR-150 in brain microvascular endothelial cells (BMVECs) exposed to oxygen glucose deprivation (OGD), thus miR-150 was predicted to be down-regulated by MYB. Moreover, MYB was confirmed to be a direct target of miR-150 by using dual luciferase reporter assay. In our previous work, we have validated VEGF as another direct target of miR-150. Therefore, MYB participates in regulation of VEGF via miR-150 under OGD, forming a feedback loop with miR-150. We also find that high levels of miR-150 inhibitors combined with MYB silence contribute to further enhancement of VEGF expression in BMVECs in response to OGD. These observations suggest that the feedback loop comprised of miR-150 and MYB, which is a pivotal endogenous epigenetic regulation to control the expression levels of VEGF in BMVECs subjected to OGD.

Human amniotic mesenchymal stem cells to promote/suppress cancer: two sides of the same coin

Cancer is a leading cause of death in both developed and developing countries, and because of population growth and aging, it is a growing medical burden worldwide. With robust development in medicine, the use of stem cells has opened new treatment modalities in cancer therapy. In adult stem cells, mesenchymal stem cells (MSCs) are showing rising promise in cancer treatment due to their unique properties. Among different sources of MSCs, human amniotic fluid/membrane is an attractive and suitable reservoir. There are conflicting opinions about the role of human amniotic membrane/fluid mesenchymal stem cells (hAMSCS/hAFMSCs) in cancer, as some studies demonstrating the anticancer effects of these cells and others suggesting their progressive effects on cancer. This review focuses on recent findings about the role of hAMSCs/hAFMSCs in cancer treatment and summarizes the suppressing as well as promoting effects of these cells on cancer progression and underling mechanisms.

The Role of MicroRNAs in Regulating Cytokines and Growth Factors in Coronary Artery Disease: The Ins and Outs

Coronary artery diseases (CAD), as a leading cause of mortality around the world, has attracted the researchers' attention for years to find out its underlying mechanisms and causes. Among the various key players in the pathogenesis of CAD cytokines, microRNAs (miRNAs) are crucial. In this study, besides providing a comprehensive overview of the involvement of cytokines, growth factors, and miRNAs in CAD, the interplay between miRNA with cytokine or growth factors during the development of CAD is discussed.

Cellular Based Strategies for Microvascular Engineering

Vascularization is a major hurdle in complex tissue and organ engineering. Tissues greater than 200 μm in diameter cannot rely on simple diffusion to obtain nutrients and remove waste. Therefore, an integrated vascular network is required for clinical translation of engineered tissues. Microvessels have been described as <150 μm in diameter, but clinically they are defined as <1 mm. With new advances in super microsurgery, vessels less than 1 mm can be anastomosed to the recipient circulation. However, this technical advancement still relies on the creation of a stable engineered microcirculation that is amenable to surgical manipulation and is readily perfusable. Microvascular engineering lays on the crossroads of microfabrication, microfluidics, and tissue engineering strategies that utilize various cellular constituents. Early research focused on vascularization by co-culture and cellular interactions, with the addition of angiogenic growth factors to promote vascular growth. Since then, multiple strategies have been utilized taking advantage of innovations in additive manufacturing, biomaterials, and cell biology. However, the anatomy and dynamics of native blood vessels has not been consistently replicated. Inconsistent results can be partially attributed to cell sourcing which remains an enigma for microvascular engineering. Variations of endothelial cells, endothelial progenitor cells, and stem cells have all been used for microvascular network fabrication along with various mural cells. As each source offers advantages and disadvantages, there continues to be a lack of consensus. Furthermore, discord may be attributed to incomplete understanding about cell isolation and characterization without considering the microvascular architecture of the desired tissue/organ.

Two way network construction and analysis of mRNA, miRNA and lncRNA reveals critical regulators and regulatory modules in cardiovascular diseases

BACKGROUND

Cardiovascular diseases contribute to the leading cause of deaths (31%) in the world population.

OBJECTIVE

The objective of this study is to compile non-coding RNA-gene interaction into a core regulatory network whose dysregulation might play an important role in disease progression.

METHOD

We applied a structured approach to reconstruct the interaction network of lncRNAs, miRNAs and genes involved in cardiovascular diseases. For network construction, we used 'diseasome to interactome' and 'interactome to diseasome' approaches and developed two regulatory networks in heart disorders. In diseasome to interactome approach, starting from a disease-centric network we, expanded the data into an interaction network. However in interactome to diseasome, we used a set of guide genes, miRNAs and lncRNAs to arrive at the common diseases. The disease-centric network in combination with the interaction network will shed light on the interconnected components in a huge diseasome network implicated in heart disorders and manifested through small sub-networks while progressing. Using the above networks we created a sub-networks consisting only of hub genes, miRNAs and lncRNAs on both approaches. The dysregulation of any one of the hubs can lead to a disease condition.

RESULTS

The top ranking hubs common in both the sub-networks were found to be VEGFA, MALAT1, HOTAIR, H19 and hsa-miR-15a. Our network based study reveals an entanglement of regulatory sub-network of miRNAs, lncRNAs and genes in multiple conditions.

CONCLUSION

The identification of hubs in the core triple node network of elements in disease development and progression demonstrates a promising role for network based approaches in targeting critical molecules for drug development.

MiR-4674 regulates angiogenesis in tissue injury by targeting p38K signaling in endothelial cells

Neoangiogenesis is critical for tissue repair in response to injury such as myocardial ischemia or dermal wound healing. MicroRNAs are small noncoding RNAs and important regulators of angiogenesis under physiological and pathological disease states. Therefore, identification of microRNAs that may restore impaired angiogenesis in response to tissue injury may provide new targets for therapy. Using a microRNA microarray profiling approach, we identified a human-specific microRNA, miR-4674, that was significantly decreased in patients after myocardial tissue injury and had an endothelial cell (EC)-enriched expression pattern. Functionally, overexpression of miR-4674 markedly attenuated EC proliferation, migration, network tube formation, and spheroid sprouting, whereas blockade of miR-4674 had the opposite effects. Transcriptomic profiling, gene set enrichment analyses, bioinformatics, 3'-untranslated region (3'-UTR) reporter and microribonucleoprotein immunoprecipitation (miRNP-IP) assays, and small interfering RNA dependency studies revealed that miR-4674 regulates VEGF stimulated-p38 mitogen-activated protein kinase (MAPK) signaling and targets interleukin 1 receptor-associated kinase 1 (Irak1) and BICD cargo adaptor 2 (Bicd2) in ECs. Furthermore, Irak1 and Bicd2 were necessary for miR-4674-driven EC proliferation and migration. Finally, neutralization of miR-4674 increased angiogenesis, Irak1 and Bicd2 expression, and p38 phosphorylation in human skin organoids as a model of tissue injury. Collectively, targeting miR-4674 may provide a novel therapeutic target for tissue repair in pathological disease states associated with impaired angiogenesis.

A regulatory microRNA network controls endothelial cell phenotypic switch during sprouting angiogenesis

Angiogenesis requires the temporal coordination of the proliferation and the migration of endothelial cells. Here, we investigated the regulatory role of microRNAs (miRNAs) in harmonizing angiogenesis processes in a three-dimensional in vitro model. We described a microRNA network which contributes to the observed down- and upregulation of proliferative and migratory genes, respectively. Global analysis of miRNA-target gene interactions identified two sub-network modules, the first organized in upregulated miRNAs connected with downregulated target genes and the second with opposite features. miR-424-5p and miR-29a-3p were selected for the network validation. Gain- and loss-of-function approaches targeting these microRNAs impaired angiogenesis, suggesting that these modules are instrumental to the temporal coordination of endothelial migration and proliferation. Interestingly, miR-29a-3p and its targets belong to a selective biomarker that is able to identify colorectal cancer patients who are responding to anti-angiogenic treatments. Our results provide a view of higher-order interactions in angiogenesis that has potential to provide diagnostic and therapeutic insights.

Antiangiogenic Effect of Alkaloids

Alkaloids are among the natural phytochemicals contained in functional foods and nutraceuticals and have been suggested for the prevention and/or management of oxidative stress and inflammation-mediated diseases. In this review, we aimed to describe the effects of alkaloids in angiogenesis, the process playing a crucial role in tumor growth and invasion, whereby new vessels form. Antiangiogenic compounds including herbal ingredients, nonherbal alkaloids, and microRNAs can be used for the control and treatment of cancers. Several lines of evidence indicate that alkaloid-rich plants have several interesting features that effectively inhibit angiogenesis. In this review, we present valuable data on commonly used alkaloid substances as potential angiogenic inhibitors. Different herbal and nonherbal ingredients, introduced as antiangiogenesis agents, and their role in angiogenesis-dependent diseases are reviewed. Studies indicate that angiogenesis suppression is exerted through several mechanisms; however, further investigations are required to elucidate their precise molecular and cellular mechanisms, as well as potential side effects.

TFEB controls vascular development by regulating the proliferation of endothelial cells

Transcription factor TFEB is thought to control cellular functions—including in the vascular bed—primarily via regulation of lysosomal biogenesis and autophagic flux. Here, we report that TFEB also orchestrates a non‐canonical program that controls the cell cycle/VEGFR2 pathway in the developing vasculature. In endothelial cells, TFEB depletion halts proliferation at the G1‐S transition by inhibiting the CDK4/Rb pathway. TFEB‐deficient cells attempt to compensate for this limitation by increasing VEGFR2 levels at the plasma membrane via microRNA‐mediated mechanisms and controlled membrane trafficking. TFEB stimulates expression of the miR‐15a/16‐1 cluster, which limits VEGFR2 transcript stability and negatively modulates expression of MYO1C, a regulator of VEGFR2 trafficking to the cell surface. Altered levels of miR‐15a/16‐1 and MYO1C in TFEB‐depleted cells cause increased expression of plasma membrane VEGFR2, but in a manner associated with low signaling strength. An endothelium‐specific Tfeb‐knockout mouse model displays defects in fetal and newborn mouse vasculature caused by reduced endothelial proliferation and by anomalous function of the VEGFR2 pathway. These previously unrecognized functions of TFEB expand its role beyond regulation of the autophagic pathway in the vascular system.

Effects of miR-503-5p on apoptosis of human pulmonary microvascular endothelial cells in simulated microgravity

Recent studies have shown that microRNA (miRNAs) can play important roles in the regulation of endothelial cell (EC) function. However, the expression profile of miRNAs and their effects on the apoptosis of ECs under microgravity conditions remains unclear. In this study, the apoptosis of human pulmonary microvascular endothelial cells (HPMECs) under simulated microgravity was identified by Annexin V and propidium iodide double staining and transmission electron microscopy. miRNA microarray assay was used to screen the differentially expressed miRNAs in HPMECs under simulated microgravity, and eight differentially expressed miRNAs were identified. Specifically, miR-503-5p, which was found to be most significantly upregulated in both microarray and quantitative reverse-transcription polymerase chain reaction assays, was selected for further functional investigation. Overexpression of miR-503-5p induced apoptosis of HPMECs under normal gravity and aggravated the negative effects of simulated microgravity on HPMECs. Furthermore, silencing of miR-503-5p expression effectively attenuated the negative effects of simulated microgravity on HPMECs. Further experiments showed that the mRNA and protein expression of anti-apoptotic factor B-cell lymphoma-2 (Bcl-2), which has been confirmed as a direct target of miR-503-5p, was inhibited by the upregulation of miR-503-5p and increased by the downregulation of miR-503-5p. Taken together, our findings demonstrate, for the first time, that miR-503-5p can induce apoptosis of HPMECs under simulated microgravity through, at least in part, inhibiting the expression of Bcl-2.

Development of the renal vasculature

The kidney vasculature has a unique and complex architecture that is central for the kidney to exert its multiple and essential physiological functions with the ultimate goal of maintaining homeostasis. An appropriate development and coordinated assembly of the different vascular cell types and their association with the corresponding nephrons is crucial for the generation of a functioning kidney. In this review we provide an overview of the renal vascular anatomy, histology, and current knowledge of the embryological origin and molecular pathways involved in its development. Understanding the cellular and molecular mechanisms involved in renal vascular development is the first step to advance the field of regenerative medicine.

The relationship of plasma miR-503 and coronary collateral circulation in patients with coronary artery disease

OBJECTIVE

Although angiogenesis plays an important role in coronary collateral circulation (CCC) formation and there are many determinants of coronary angiogenesis, they cannot fully explain the mechanism of CCC formation or as potent biomarker for CCC status. Therefore, there is of great clinical significance to identify the novel molecules associated with CCC. Previously, miR-503 exerts anti-angiogenesis effect via inhibition of VEGF-A and its expression is associated with many angiogenesis-related factors. Thus, we aimed to investigate the relationship of plasma miR-503 with CCC formation as well as its predictive power for CCC status in patients with coronary artery disease.

METHODS

Among patients who underwent coronary angiography with coronary artery disease and a stenosis of ≥90% were included in our study. Collateral degree was graded according to Rentrop Cohen classification. The patients were divided to good CCC group (grade 2 or 3) and poor CCC group (grade 0 or 1) according to Rentrop grade. We investigated the plasma levels of miR-503 and VEGF-A by ELISA or q RT-PCR, respectively. In addition, we assayed the correlations of plasma miR-503 with VEGF-A or Rentrop grade using the spearman correlation test and its predictive power by receiver operating characteristic (ROC) and binary logistical regression analysis.

RESULTS

Our data showed that plasma VEGF-A was significantly higher in good CCC group than that in poor group. Plasma miR-503 was lower in CAD patients with good CCC or poor CCC compared with control subjects and lowest in good CCC group. In addition, miR-503 negatively correlated with VEGF-A and Rentrop grade, respectively. Moreover, miR-503 displayed more potent predictive power for CCC status than VEGF-A, but its sensitivity and specificity for CCC status were only 72.4 or 60.9%, respectively.

CONCLUSIONS

Lower plasma miR-503 level was related to better CCC formation, accompanied by up-regulation of VEGF-A. In addition, miR-503 displayed potent predictive power for CCC status, but its sensitivity and specificity were not high enough, indicating that miR-503 might be as an additional prognosis biomarker for CCC.

MicroRNAs and the response to injury in atherosclerosis

Endothelial cells (ECs) at arterial branching points are physiologically subjected to chronic damage by disturbed blood flow, which triggers a vascular wound healing response. Additional damage by hyperlipid -aemia perturbs this delicate balance of en-dothelial injury and regeneration, and the progressive accumulation of noxious modified lipoproteins leads to macrophage death. Several miRNAs such as miR-92a and miR-712, which modulate EC proliferation and inflammation, are up-regulated by disturbed flow in ECs, and contribute to atherosclerosis. In addition, reduced endothelial levels of miR-126–5p limit the regenerative capacity of ECs, which becomes apparent by insufficient endothelial repair under hyperlipidemic stress. In macrophages, miR-342–5p induces the expression of miR-155 during the progression of atherosclerosis, which promotes inflammatory gene expression and inhibits efferocytosis by targeting Bcl6, thus contributing to necrotic core formation. Deciphering the complex cell- and context-specific effects of miRNAs during vascular wound healing appears essential for the development of miRNA-based therapies of atherosclerosis.

Cilostazol attenuates intimal hyperplasia in a mouse model of chronic kidney disease

Intimal hyperplasia (IH) is a common cause of vasculopathy due to direct endothelial damage (such as post-coronary revascularization) or indirect injury (such as chronic kidney disease, or CKD). Although the attenuation of coronary revascularization-induced IH (direct-vascular-injury-induced IH) by cilostazol, a phosphodiesterase III inhibitor, has been demonstrated, our understanding of the effect on CKD-induced IH (indirect-vascular-injury-induced IH) is limited. Herein, we tested if cilostazol attenuated CKD-induced IH in a mouse model of ischemic-reperfusion injury with unilateral nephrectomy (Chr I/R), a normotensive non-proteinuria CKD model. Cilostazol (50 mg/kg/day) or placebo was orally administered once daily from 1-week post-nephrectomy. At 20 weeks, cilostazol significantly attenuated aortic IH as demonstrated by a 34% reduction in the total intima area with 50% and 47% decreases in the ratios of tunica intima area/tunica media area and tunica intima area/(tunica intima + tunica media area), respectively. The diameters of aorta and renal function were unchanged by cilostazol. Interestingly, cilostazol decreased miR-221, but enhanced miR-143 and miR-145 in either in vitro or aortic tissue, as well as attenuated several pro-inflammatory mediators, including asymmetrical dimethylarginine, high-sensitivity C-reactive protein, vascular endothelial growth factor in aorta and serum pro-inflammatory cytokines (IL-6 and TNF-α). We demonstrated a proof of concept of the effectiveness of cilostazol in attenuating IH in a Chr I/R mouse model, a CKD model with predominantly indirect-vascular-injury-induced IH. These considerations warrant further investigation to develop a new primary prevention strategy for CKD-related IH.

Amniotic fluid stem cell-derived vesicles protect from VEGF-induced endothelial damage

Injection of amniotic fluid stem cells (AFSC) delays the course of progression of renal fibrosis in animals with Alport Syndrome, enhancing kidney function and improving survival. The mechanisms responsible for these protective outcomes are still largely unknown. Here, we showed that vascular endothelial growth factor (VEGF) signaling within the glomeruli of Alport mice is strongly elevated early on in the disease, causing glomerular endothelial cell damage. Intraventricular injected AFSC that homed within the glomeruli showed strong modulation of the VEGF activity, particularly in glomerular endothelial cells. To investigate this phenomenon we hypothesized that extracellular vesicles (EVs) produced by the AFSC could be responsible for the observed renoprotection. AFSC derived EVs presented exosomal and stem cell markers on their surface membrane, including VEGFR1 and VEGFR2. EVs were able to modulate VEGF in glomerular endothelial cells by effectively trapping the excess VEGF through VEGFR1-binding preventing cellular damage. In contrast, VEGFR1/sVEGFR1 knockout EVs failed to show similar protection, thus indicating that VEGF trapping is a potentially viable mechanism for AFSC-EV mediated renoprotection. Taken together, our findings establish that EVs secreted by AFSC could target a specific signaling pathway within the glomerulus, thus representing a new potential glomerulus-specific targeted intervention.

MiR-34a regulates mitochondrial content and fat ectopic deposition induced by resistin through the AMPK/PPARα pathway in HepG2 cells

Resistin is an adipocyte-derived cytokine and was named for its role in the development of insulin resistance. Increased serum resistin levels are also associated with steatohepatitis and non-alcoholic fatty liver disease. In a previous study, resistin was observed to reduce mitochondrial content and upregulate miR-34a significantly in the liver. In this study, male C57BL/6 mice were injected with agomir-34a or control agomir, and HepG2 cells were transfected with miR-34a mimics or inhibitors to assess their role in resistin-induced fat deposition. The overexpression of miR-34a increased liver and HepG2 cell TAG content, decreased mitochondrial content, changed mitochondrial morphology and impaired mitochondrial function. In contrast, a miR-34a inhibitor significantly restored the TAG content and mitochondrial transmembrane potential. A study of transcriptional regulation revealed that C/EBPβ is essential for upregulating miR-34a by resistin. Furthermore, miR-34a inhibited the PPARα signaling pathway by binding to sites in the 3'UTR of AdipoR2 genes and the AMPK pathway. Consequently, this increased the fat content and decreased the mitochondrial content in HepG2 cells. This paper reveals a novel mechanism for mitochondrial regulation, which suggests that normal mitochondrial content and function is crucial for lipid metabolism in the liver.

Upregulation of miR-126-3p promotes human saphenous vein endothelial cell proliferation in vitro and prevents vein graft neointimal formation ex vivo and in vivo

Poor long-term patency of vein grafts remains an obstacle in coronary artery bypass grafting (CABG) surgery using an autologous saphenous vein graft. Recent studies have revealed that miR-126-3p promotes vascular integrity and angiogenesis. We aimed to identify the role of miR-126-3p in the setting of vein graft disease and investigate the value of miR-126-3p agomir as a future gene therapy in vein graft failure. Expression analysis of circulating miR-126-3p in plasma from CABG patients established the basic clues that miR-126-3p participates in CABG. The in vitro results indicated that elevated miR-126-3p expression significantly improved proliferation and migration in human saphenous vein endothelial cells (HSVECs) by targeting sprouty-related protein-1 (SPRED-1) and phosphatidylinositol-3-kinase regulatory subunit 2 (PIK3R2), but not in human saphenous vein smooth muscle cells (HSVSMCs). Moreover, the therapeutic potential of miR-126-3p agomir was demonstrated in cultured human saphenous vein (HSV) ex vivo. Finally, local delivery of miR-126-3p agomir was confirmed to enhance reendothelialization and attenuate neointimal formation in a rat vein arterialization model. In conclusion, we provide evidence that upregulation of miR-126-3p by agomir possesses potential clinical value in the prevention and treatment of autologous vein graft restenosis in CABG.

MiR-206 Suppresses the Progression of Coronary Artery Disease by Modulating Vascular Endothelial Growth Factor (VEGF) Expression

Background

We investigated whether microRNA-206 (miR-206) is abnormally expressed in patients with coronary artery disease (CAD). The potential mechanism by which miR-206 may regulate CAD progression was also studied.

Material/Methods

A total of 78 CAD patients in the case group and 65 subjects in the control group were enrolled in this study so that the correlation between miR-206 and CAD could be accurately determined. Serum total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides were detected using a biochemistry analyzer. MiR-206 and vascular endothelial growth factor (VEGF) expression levels were tested using either reverse transcription polymerase chain reaction or western blot. Associations between miR-206 expression and different clinicopathological features of CAD patients were also analyzed. CAD cells were transfected with miR-206 mimic (miR-206), its negative control (miR-NC), miR-206 inhibitor (anti-miR-206), and its negative control (anti-miR-NC), respectively. Flow cytometry was conducted to explore the function of miR-206 in CAD cell apoptosis after transfection. Moreover, transwell assay was carried out to study the migratory ability of endothelial progenitor cells (EPCs) in CAD patients.

Results

MiR-206 expression was enriched in both diseased EPCs and plasma of CAD patients. No significant correlation was found between decrease in miR-206 expression and different clinicopathological features. In addition, miR-206 significantly suppressed the viability and invasion of EPCs in CAD patients, and it promoted the apoptosis of their EPCs. Moreover, we found that miR-206 is able to inhibit VEGF expression.

Conclusions

As suggested by our study, MiR-206 can be a novel benign biomarker for CAD because it may regulate VEGF expression.

MicroRNA let-7g inhibited hypoxia-induced proliferation of PASMCs via G0/G1 cell cycle arrest by targeting c-myc

AIMS

Pulmonary hypertension (PH) is a proliferative disorder characterized by enhanced proliferation and suppressed apoptosis of intrapulmonary vascular smooth muscle cells. Recently, network-based bioinformatics have identified let-7 family, a tumor suppressive microRNA, regulate multiple interacting targets relevant to PH. However, the role of let-7 in vascular homeostasis in PH remains unknown. Thus, we wanted to investigate the role of let-7 in hypoxia-induced PASMCs proliferation and the underlying mechanism in hypoxic pulmonary hypertension (HPH).

MAIN METHODS

The male Sprague-Dawley (SD) rats were exposed to hypoxia (10% O₂) for 21days to induce HPH. The expression of let-7 was determined by quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization. Primary rat PASMCs were exposed to hypoxia (3% O₂). MTS and EDU were performed to evaluate PASMCs proliferation. The mRNA and protein expression of c-myc, Bmi-1 and p16 were determined by qRT-PCR and Western blotting, respectively. The functions of let-7g on PASMCs proliferation, c-myc, Bmi-1 and p16 expression were assessed by let-7g mimic and inhibitor transfection.

KEY FINDINGS

Among let-7 family members, only let-7b and let-7g were significantly down-regulated in remodeled pulmonary artery in HPH rats. Furthermore, only let-7g level was decreased in hypoxic PASMCs. Either hypoxia or let-7g inhibitor stimulated proliferation of PASMCs, let-7g mimic inhibited hypoxia-induced PASMCs proliferation. C-myc was the target of let-7g in PASMCs. Transfect of let-7g mimic inhibited hypoxia-induced c-myc, Bmi-1 up-regulation and p16 down-regulation, which ultimately controls cell cycle progression.

SIGNIFICANCE

Loss of inhibition on c-myc-Bmi-1-p16 signaling pathway by let-7g may lead to PASMCs proliferation and vascular remodeling in HPH.

CCL3 promotes angiogenesis by dysregulation of miR-374b/ VEGF-A axis in human osteosarcoma cells

Osteosarcoma is the most frequent bone tumor, characterized by a high metastatic potential. However, the crosstalk between chemokine (C-C motif) ligand 3 (CCL3), which facilitates tumor progression and metastasis. Vascular endothelial growth factor-A (VEGF-A), an angiogenesis inducer and a highly specific mitogen for endothelial cells, has not been well explored in human osteosarcoma. Here we demonstrate the correlation of CCL3 and VEGF-A expressions, quantified by immunohistochemistry, with the tumor stage of human osteosarcoma tissues. Furthermore, CCL3 promotes VEGF-A expression in human osteosarcoma cells that subsequently induces human endothelial progenitor cell (EPC) migration and tube formation. Phosphorylation of JNK, ERK, and p38 was found after CCL3 stimulation. In addition, JNK, ERK, and p38 inhibitors also abolished CCL3-induced VEGF-A expression and angiogenesis. We noted that CCL3 reduces the expression of miR-374b and miR-374b mimic by reversing CCL3-promoted VEGF-A expression and angiogenesis in vitro and in vivo. This study shows that CCL3 promotes VEGF-A expression and angiogenesis in human osteosarcoma cells by down-regulating miR-374b expression via JNK, ERK, and p38 signaling pathways. Thus, CCL3 may be a new molecular therapeutic target in osteosarcoma angiogenesis and metastasis.

Limb ischemia and vessel regeneration: Is there a role for VEGF?

Vascular endothelial growth factor (VEGF), as an endothelial cell-specific mitogen, is crucial for new blood vessels formation. Atherosclerosis affecting the cardiovascular system causes ischemia and functio laesa in tissues supplied by the occluded vessels. When such a situation occurs in the lower extremities, it causes critical limb ischemia (CLI) often requiring leg amputation. Low oxygen tension leads to upregulation of hypoxia-regulated genes (i.e. VEGF), that should help to restore the impaired blood flow. In CLI these rescue mechanisms are, however, often inefficient. Moreover, there are many contradictory reports showing either induction, no changes or even down-regulation of VEGF in specimens taken from patients with CLI, as well as in samples collected from animals subjected to hindlimb ischemia. Additionally, taking into account numerous experimental and clinical data demonstrating rather insufficient therapeutic potential of VEGF, we called into question the role of this protein in limb ischemia and vessel regeneration. In this review we are also summarizing several aspects which can influence VEGF expression and its measurement in the ischemic tissues.

Differential expression of microRNAs in retinal vasculopathy caused by selective Müller cell disruption

Vascular changes and photoreceptor degeneration are features of age-related macular degeneration, diabetic retinopathy and macular telangiectasis. We have profiled the differential expression of microRNAs and analysed their target genes in transgenic mice in which induced Müller cell disruption results in photoreceptor degeneration, vascular leak and deep retinal neovascularisation. We identified 9 miRNAs which were differentially expressed during the development of retinal neovascularization and chose miR-200b and its target genes for further study. Using qRT-PCR and western blot analysis, we found that downregulation of miR-200b was negatively correlated with its target genes, including zinc finger E-box binding homeobox (ZEB) 1 and 2 and vascular endothelial growth factor receptor 1. Double immunofluorescence labelling revealed that the newly formed vessels in the outer retina were positive for ZEB2. Furthermore, intravitreal injections of a miR-200b-mimic and anti-miR-200b confirmed the negative correlation of miR-200b and its target gene expression. We also found that the miR-200b-mimic inhibited vascular leak in the established mild vascular lesions, whereas anti-miR-200b promoted it. Taken together, these data suggest that miR-200b may play a role in the development of intraretinal neovascularisation.

MicroRNA-223 Attenuates Hypoxia-induced Vascular Remodeling by Targeting RhoB/MLC2 in Pulmonary Arterial Smooth Muscle Cells

There is growing evidence that microRNAs are implicated in pulmonary arterial hypertension (PAH), but underlying mechanisms remain elusive. Here, we identified that miR-223 was significantly downregulated in chronically hypoxic mouse and rat lungs, as well as in pulmonary artery and pulmonary artery smooth muscle cells (PASMC) exposed to hypoxia. Knockdown of miR-223 increased PASMC proliferation. In contrast, miR-223 overexpression abrogated cell proliferation, migration and stress fiber formation. Administering miR-223 agomir in vivo antagonized hypoxia-induced increase in pulmonary artery pressure and distal arteriole muscularization. RhoB, which was increased by hypoxia, was identified as one of the targets of miR-223. Overexpressed miR-223 suppressed RhoB and inhibited the consequent phosphorylation of myosin phosphatase target subunit (MYPT1) and the expression of myosin light chain of myosin II (MLC2), which was identified as another target of miR-223. Furthermore, serum miR-223 levels were decreased in female patients with PAH associated with congenital heart disease. Our study provides the first evidence that miR-223 can regulate PASMC proliferation, migration, and actomyosin reorganization through its novel targets, RhoB and MLC2, resulting in vascular remodeling and the development of PAH. It also highlights miR-223 as a potential circulating biomarker and a small molecule drug for diagnosis and treatment of PAH.

Characteristics of resistin in rheumatoid arthritis angiogenesis

Adipokines have been reported to be involved in the regulation of various physiological processes, including the immune response. Rheumatoid arthritis (RA) is an example of a systemic immune disease that causes chronic inflammation of the synovium and bone destruction in the joint. Recent therapeutic strategies based on the understanding of the role of cytokines and cellular mechanisms in RA have improved our understanding of angiogenesis. On the other hand, endogenous endothelial progenitor cells, which are a population isolated from peripheral blood monocytes have recently been identified as a homing target for pro-angiogeneic factor and vessel formation. In this review, we summarize the effects of common adipokines, such as adiponectin, leptin and resistin in RA pathogenesis and discuss other potential mechanisms of relevance for the therapeutic treatment of RA.

Junb controls lymphatic vascular development in zebrafish via miR-182

JUNB, a subunit of the AP-1 transcription factor complex, mediates gene regulation in response to a plethora of extracellular stimuli. Previously, JUNB was shown to act as a critical positive regulator of blood vessel development and homeostasis as well as a negative regulator of proliferation, inflammation and tumour growth. Here, we demonstrate that the oncogenic miR-182 is a novel JUNB target. Loss-of-function studies by morpholino-mediated knockdown and the CRISPR/Cas9 technology identify a novel function for both JUNB and its target miR-182 in lymphatic vascular development in zebrafish. Furthermore, we show that miR-182 attenuates foxo1 expression indicating that strictly balanced Foxo1 levels are required for proper lymphatic vascular development in zebrafish. In conclusion, our findings uncover with the Junb/miR-182/Foxo1 regulatory axis a novel key player in governing lymphatic vascular morphogenesis in zebrafish.

MiR-34a is Involved in the Decrease of ATP Contents Induced by Resistin Through Target on ATP5S in HepG2 Cells

Resistin is associated with metabolic syndrome and deciphering its developmental and molecular mechanisms may help the development of new treatments. MiRNAs serve as negative regulators in many physiological and pathological processes. Here, miRNA microarrays were used to detect differences in expression between resistin-treated and control mice, and results showed miR-34a to be upregulated by resistin. The purpose of this study was to determine whether miR-34a played a role in resistin-induced decrease of ATP contents. Transient transfection of miR-34a mimics was used to overexpress miR-34a and quantitative RT-PCR was used to detect its expression. Western blot analysis was used to determine the rate of expression at the protein level. ATP content was measured using an ATP assay kit. The target gene of miR-34a was analyzed using bioinformatics and confirmed with dual-luciferase report system. MiR-34a was upregulated by resistin in HepG2 cells, and overexpression of miR-34a was found to diminish ATP levels significantly. This study is the first to show that ATP5S is one of the target genes of miR-34a. Resistin diminishes ATP content through the targeting of ATP5S mRNA 3'UTR by miR-34a.

Therapeutic Angiogenesis by Ultrasound-Mediated MicroRNA-126-3p Delivery

OBJECTIVE

MicroRNAs are involved in many critical functions, including angiogenesis. Ultrasound-targeted microbubble destruction (UTMD) is a noninvasive technique for targeted vascular transfection of plasmid DNA and may be well suited for proangiogenic microRNA delivery. We aimed to investigate UTMD of miR-126-3p for therapeutic angiogenesis in chronic ischemia.

APPROACH AND RESULTS

The angiogenic potential of miR-126-3p was tested in human umbilical vein endothelial cells in vitro. UTMD of miR-126-3p was tested in vivo in Fischer-344 rats before and after chronic left femoral artery ligation, evaluating target knockdown, miR-126-3p and miR-126-5p expression, phosphorylated Tie2 levels, microvascular perfusion, and vessel density. In vitro, miR-126-3p-transfected human umbilical vein endothelial cells showed repression of sprouty-related protein-1 and phosphatidylinositol-3-kinase regulatory subunit 2, negative regulators of vascular endothelial growth factor and angiopoietin-1 signaling, increased phosphorylated Tie2 mediated by knockdown of phosphatidylinositol-3-kinase regulatory subunit 2 and greater angiogenic potential mediated by both vascular endothelial growth factor/vascular endothelial growth factor R2 and angiopoietin-1 /Tie2 effects. UTMD of miR-126-3p resulted in targeted vascular transfection, peaking early after delivery and lasting for >3 days, and resulting in inhibition of sprouty-related protein-1 and phosphatidylinositol-3-kinase regulatory subunit 2, with minimal uptake in remote organs. Finally, UTMD of miR-126-3p to chronic ischemic hindlimb muscle resulted in improved perfusion, vessel density, enhanced arteriolar formation, pericyte coverage, and phosphorylated Tie2 levels, without affecting miR-126-5p or delta-like 1 homolog levels.

CONCLUSIONS

UTMD of miR-126 results in improved tissue perfusion and vascular density in the setting of chronic ischemia by repressing sprouty-related protein-1 and phosphatidylinositol-3-kinase regulatory subunit 2 and enhancing vascular endothelial growth factor and angiopoietin-1 signaling, with no effect on miR-126-5p. UTMD is a promising platform for microRNA delivery, with applications for therapeutic angiogenesis.

Biochemically engineered stromal cell-derived factor 1-alpha analog increases perfusion in the ischemic hind limb

BACKGROUND

Despite promising therapeutic innovation over the last decade, peripheral arterial disease remains a prevalent morbidity, as many patients are still challenged with peripheral ischemia. We hypothesized that delivery of engineered stromal cell-derived factor 1-alpha (ESA) in an ischemic hind limb will yield significant improvement in perfusion.

METHODS

Male rats underwent right femoral artery ligation, and animals were randomized to receive a 100 μL injection of saline (n = 9) or 6 μg/kg dosage of equal volume of ESA (n = 12) into the ipsilateral quadriceps muscle. Both groups of animals were also given an intraperitoneal injection of 40 μg/kg of granulocyte macrophage colony-stimulating factor (GMCSF). Perfusion was quantified using a laser Doppler imaging device preoperatively, and on postoperative days 0, 7, and 14. Immunohistochemistry was performed to quantify angiogenesis on day 14, and an mRNA profile was evaluated for angiogenic and inflammatory markers.

RESULTS

Compared with the saline/GMCSF group at day 14, the ESA/GMCSF-injected animals had greater reperfusion ratios (Saline/GMCSF, 0.600 ± 0.140 vs ESA/GMCSF, 0.900 ± 0.181; group effect P = .006; time effect P < .0001; group×time effect P < .0001), elevated capillary density (10×; Saline/GMCSF, 6.40 ± 2.01 vs ESA/GMCSF, 18.55 ± 5.30; P < .01), and increased mRNA levels of vascular endothelial growth factor-A (Saline/GMCSF [n = 6], 0.298 ± 0.205 vs ESA/GMCSF [n = 8], 0.456 ± 0.139; P = .03).

CONCLUSIONS

Delivery of ESA significantly improves perfusion in a rat model of peripheral arterial disease via improved neovasculogenesis, a finding which may prove beneficial in the treatment strategy for this debilitating disease.

High concentrations of uric acid inhibit angiogenesis via regulation of the Krüppel-like factor 2-vascular endothelial growth factor-A axis by miR-92a

BACKGROUND

Angiogenesis is a critical component of many pathological conditions, and microRNAs (miRNAs) are indispensable in angiogenesis. It is unclear whether miRNAs regulate angiogenesis in the presence of high concentrations of uric acid (HUA), and the underlying mechanisms remain unknown.

METHODS AND RESULTS

It was found that HUA inhibited the angiogenic ability of endothelial cells. miRNA expression profiling was conducted using microarray assays in HUA-stimulated endothelial cells. Eighteen differentially expressed miRNAs were subjected to bioinformatic analyses. The results indicated that miR-92a was negatively regulated and was closely related to angiogenesis. Furthermore, the effects of miR-92a on HUA-stimulated endothelial cell angiogenesis and the underlying mechanisms were investigated in dual-luciferase reporter assays, electrophoretic mobility shift assays, immunoblot assays, and tube formation assays. It was determined that Krüppel-like factor 2 (KLF2) is a target gene of miR-92a, and KLF2 binds the vascular endothelial growth factor-A (VEGFA) promoter to inhibit its expression. miR-92a and VEGFA overexpression or KLF2 downregulation alleviates the HUA-mediated inhibition of angiogenesis in endothelial cells in vitro.

CONCLUSIONS

This study reported that there is a novel pathway regulating angiogenesis under HUA conditions. In the presence of HUA, miR-92a downregulation increased KLF2 expression, subsequently inhibiting VEGFA, which resulted in decreased angiogenesis. Thus, this study reports a possible mechanism for cardiovascular injury caused by hyperuricemia and suggests that the miR-92a-KLF2-VEGFA axis may be a target for hyperuricemia treatment.

Resistin Promotes Angiogenesis in Endothelial Progenitor Cells Through Inhibition of MicroRNA206: Potential Implications for Rheumatoid Arthritis

Endothelial progenitor cells (EPCs) promote angiogenesis and are therefore key contributors to a wide variety of angiogenesis-related autoimmune diseases such as rheumatoid arthritis (RA). However, the signaling mechanisms through which these progenitor cells influence RA pathogenesis remain unknown. The aim of this study was to examine whether resistin plays a role in the pathogenesis of and angiogenesis associated with RA by circulating EPCs. We found that levels of resistin in synovial fluid and tissue from patients with RA and from mice with collagen-induced arthritis were overexpressed and promoted the homing of EPCs into the synovium, thereby inducing angiogenesis. EPCs isolated from healthy donors were used to investigate the signal transduction pathway underlying EPC migration and tube formation after treatment with resistin. We found that resistin directly induced a significant increase in expression of vascular endothelial growth factor (VEGF) in EPCs. We also found that the expression of microRNA-206 (miR-206) was negatively correlated with the expression of resistin during EPC-mediated angiogenesis. Notably, the increased expression of VEGF was associated with decreased binding of miR-206 to the VEGF-A 3' untranslated region through protein kinase C delta-dependent AMP-activated protein kinase signaling pathway. Moreover, blockade of resistin reduced EPC homing into synovial fluid and angiogenesis in vivo. Taken together, our study is the first to demonstrate that resistin promotes EPCs homing into the synovium during RA angiogenesis via a signal transduction pathway that involves VEGF expression in primary EPCs. These findings provide support for resistin as a therapeutic target for the patients with RA. Stem Cells 2015;33:2243-2255.

Establishment and characterization of a novel VEGF-producing HHV-8-unrelated PEL-like lymphoma cell line, OGU1

Primary effusion lymphoma (PEL) is a rare B-cell lymphoma subtype that is characterized by lymphomatous effusion without the presence of masses, and it typically occurs in human immunodeficiency virus (HIV)-infected individuals. Lymphoma cells are universally positive for human herpesvirus 8 (HHV-8). Recently, a cavity-based effusion lymphoma that is similar to PEL without HHV-8 infection, called HHV-8-unrelated PEL-like lymphoma, has been reported in non-HIV-infected individuals. However, the pathophysiology of this lymphoma is largely undefined. We established a novel B-cell line OGU1 derived from a patient with HHV-8-unrelated PEL-like lymphoma. Notably, OGU1 cells produced vascular endothelial growth factor (VEGF) and expressed VEGF receptor 1, whose inhibitors retarded cell growth. Because VEGF acts as a vascular permeability and growth factor, it could play a role, at least in part, in the pathogenesis of this unique lymphoma. Thus, the OGU1 cell line is useful for the investigation of HHV-8-unrelated PEL-like lymphoma.

Discovery of prognostic factors for diagnosis and treatment of epithelial-derived ovarian cancer from laying hens

Ovarian cancer is a lethal gynecological cancer causing cancer-related deaths in women worldwide. It is difficult to diagnosis at an early stage when more than 90% patients can be cured because of lack of specific symptoms and early detection markers. Most of malignant ovarian tumors are originated from the germinal epithelium of the ovary. For investigation with animal models of epithelial-derived ovarian cancer (EOC), laying hens are the most relevant animal models because they spontaneously develop EOC as occurs in women through ovulating almost every day. As in women, EOC in the hen is age-related and grossly and histologically similar to that in women. However, domesticated animals are inappropriate for research human EOC due to multiple pregnancies and lactating or seasonally anestrous. In addition, the non-spontaneous nature of rodents EOC limits clinical relevance with human EOC. Recent studies have shown that ovarian cancer could arise from epithelium from the oviduct as oviduct-related genes are up-regulated in EOC of hens. Therefore, we showed in the review: 1) characterization and classification of EOC; 2) chicken models for EOC; 3) relationship estrogen with EOC; 4) candidate prognostic factors for EOC including serpin peptidase inhibior, clade B (ovalbumin), member 3 (SERPINB3), SERPINB11, gallicin 11 (GAL11), secreted phosphoprotein 1 (SPP1) and alpha 2 macroglobulin (A2M) in normal and cancerous ovaries of laying hens; 5) biological roles of microRNAs in development of EOC. Collectively, the present reviews indicate that expression of SERPINB3, SERPINB11, GAL11, SPP1 and A2M is clearly associated with the development of ovarian carcinogenesis. These results provide new insights into the prognostic biomarkers for EOC to diagnose and to evaluate responses to therapies for treating EOC of humans.

Role of microRNA-93 in regulation of angiogenesis

Angiogenesis is essential for a wide variety of physiological and pathological processes. To date, many angiogenic microRNAs (miRNAs) have been identified and several of them were further investigated to elucidate the mechanisms of specific miRNAs in regulating angiogenesis. In recent studies concerning tumor and ischemia, the miRNA-93 had been demonstrated to be able to modulate angiogenesis in different molecular pathways. The miRNA-93 can promote angiogenesis via enhancing endothelial cell proliferation, migration, and tube formation. Additionally, miRNA-93-over-expressing cells developed a relationship with the blood vessels allowing tumor cells to survive and to grow well. However, high expression of miRNA-93 can depress the vascular endothelial growth factor (VEGF) secretion and its downstream molecular targets in in vivo and vitro experiments. MiRNA-93's effects on angiogenesis are dependent on the interaction of other multiple genes and signal pathways, such as P21, E2F1, integrin-β8, LATS2, etc. Future investigation should involve mapping the network by which miRNA-93 exerts its functions.

MicroRNAs, immune cells and pregnancy

MicroRNAs (miRNAs) are a recently discovered class of non-coding RNAs that are expressed in many cell types, where they regulate the expression of complementary RNAs, thus modulating the stability and translation of mRNAs. miRNAs are predicted to regulate the expression of ∼50% of all protein coding genes in mammals. Therefore, they participate in virtually all cellular processes investigated so far. Altered miRNAs expressions are associated with both physiological (pregnancy) and pathological processes (cancer). As the dynamic maternal-fetal interface plays a critical role in the maintenance of successful pregnancy, it is not surprising that the miRNAs that are unique to reproductive tissues are abundantly expressed. Research in this field has demonstrated the presence and dysregulation of a distinct set of pregnancy-associated miRNAs; however, most studies have centered on localizing various miRNAs in reproductive microdomains associated with normal or complicated pregnancies. Although several independent miRNA regulatory mechanisms associated with endometrial receptivity, immune cells, angiogenesis and placental development have been studied, miRNA-mediated regulation of pregnancy remains poorly understood. This review provides a summary of the current data on miRNA regulation as well as functional profiles of miRNAs that are found in the uterus, in immune cells associated with maternal tolerance to the fetus, and those involved in angiogenesis and placental development.

Dysregulated miR-361-5p/VEGF axis in the plasma and endothelial progenitor cells of patients with coronary artery disease

Dysfunction and reduction of circulating endothelial progenitor cell (EPC) is correlated with the onset of cardiovascular disorders including coronary artery disease (CAD). VEGF is a known mitogen for EPC to migrate out of bone marrow to possess angiogenic activities, and the plasma levels of VEGF are inversely correlated to the progression of CAD. Circulating microRNAs (miRNAs) in patient body fluids have recently been considered to hold the potential of being novel disease biomarkers and drug targets. However, how miRNAs and VEGF cooperate to regulate CAD progression is still unclear. Through the small RNA sequencing (smRNA-seq), we deciphered the miRNome patterns of EPCs with different angiogenic activities, hypothesizing that miRNAs targeting VEGF must be more abundant in EPCs with lower angiogenic activities. Candidates of anti-VEGF miRNAs, including miR-361-5p and miR-484, were enriched in not only diseased EPCs but also the plasma of CAD patients. However, we found out only miR-361-5p, but not miR-484, was able to suppress VEGF expression and EPC activities. Reporter assays confirmed the direct binding and repression of miR-361-5p to the 3′-UTR of VEGF mRNA. Knock down of miR-361-5p not only restored VEGF levels and angiogenic activities of diseased EPCs in vitro, but further promoted blood flow recovery in ischemic limbs of mice. Collectively, we discovered a miR-361-5p/VEGF-dependent regulation that could help to develop new therapeutic modalities not only for ischemia-related diseases but also for tumor angiogenesis.