MicroRNA-30 mediates anti-inflammatory effects of shear stress and KLF2 via repression of angiopoietin 2

MicroRNAs regulate the vicious cycle of vascular calcification-osteoporosis in postmenopausal women

Menopause is a normal physiological process accompanied by changes in various physiological states. The incidence of vascular calcification (VC) increases each year after menopause and is closely related to osteoporosis (OP). Although many studies have investigated the links between VC and OP, the interaction mechanism of the two under conditions of estrogen loss remains unclear. MicroRNAs (miRNAs), which are involved in epigenetic modification, play a critical role in estrogen-mediated mineralization. In the past several decades, miRNAs have been identified as biomarkers or therapeutic targets in diseases. Thus, we hypothesize that these small molecules can provide new diagnostic and therapeutic approaches. In this review, we summarize the close interactions between VC and OP and the role of miRNAs in their interplay.

MicroRNAs and Cardiovascular Disease Risk

PURPOSE OF REVIEW

MicroRNAs (miRNAs)-short, non-coding RNAs-play important roles in almost all aspects of cardiovascular biology, and changes in intracellular miRNA expression are indicative of cardiovascular disease development and progression. Extracellular miRNAs, which are easily measured in blood and can be reflective of changes in intracellular miRNA levels, have emerged as potential non-invasive biomarkers for disease. This review summarizes current knowledge regarding miRNAs as biomarkers for assessing cardiovascular disease risk and prognosis.

RECENT FINDINGS

Numerous studies over the last 10-15 years have identified associations between extracellular miRNA profiles and cardiovascular disease, supporting the potential use of extracellular miRNAs as biomarkers for risk stratification. However, clinical application of extracellular miRNA profiles has been hampered by poor reproducibility and inter-study variability that is due largely to methodological differences between studies. While recent studies indicate that circulating extracellular miRNAs are promising biomarkers for cardiovascular disease, evidence for clinical implementation is lacking. This highlights the need for larger, well-designed studies that use standardized methods for sample preparation, miRNA isolation, quantification, and normalization.

Differentiation-inducing factor-1 reduces lipopolysaccharide-induced vascular cell adhesion molecule-1 by suppressing mTORC1-S6K signaling in vascular endothelial cells

AIMS

Differentiation-inducing factor-1 (DIF-1), a compound in Dictyostelium discoideum, exhibits anti-cancer effects by inhibiting cell proliferation and motility of various mammalian cancer cells in vitro and in vivo. In addition, DIF-1 suppresses lung colony formation in a mouse model, thus impeding cancer metastasis. However, the precise mechanism underlying its anti-metastatic effect remains unclear. In the present study, we aim to elucidate this mechanism by investigating the adhesion of circulating tumor cells to blood vessels using in vitro and in vivo systems.

MAIN METHODS

Melanoma cells (1.0 × 105 cells) were injected into the tail vein of 8-week-old male C57BL/6 mice after administration of DIF-1 (300 mg/kg per day) and/or lipopolysaccharide (LPS: 2.5 mg/kg per day). To investigate cell adhesion and molecular mechanisms, cell adhesion assay, western blotting, immunofluorescence staining, and flow cytometry were performed.

KEY FINDINGS

Intragastric administration of DIF-1 suppressed lung colony formation. DIF-1 also substantially inhibited the adhesion of cancer cells to human umbilical vein endothelial cells. Notably, DIF-1 did not affect the expression level of adhesion-related proteins in cancer cells, but it did decrease the expression of vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells by suppressing its mRNA-to-protein translation through inhibition of mTORC1-p70 S6 kinase signaling.

SIGNIFICANCE

DIF-1 reduced tumor cell adhesion to blood vessels by inhibiting mTORC1-S6K signaling and decreasing the expression of adhesion molecule VCAM-1 on vascular endothelial cells. These findings highlight the potential of DIF-1 as a promising compound for the development of anti-cancer drugs with anti-metastatic properties.

Higher gestational weight gain delays wound healing and reduces expression of long non-coding RNA KLRK1-AS1 in neonatal endothelial progenitor cells

High gestational weight gain (GWG) is a cardiovascular risk factor and may disturb neonatal endothelial function. Long non-coding RNAs (lncRNAs) regulate gene expression epigenetically and can modulate endothelial function. Endothelial colony forming cells (ECFCs), circulating endothelial precursors, are a recruitable source of endothelial cells and sustain endothelial function, vascular growth and repair. We here investigated whether higher GWG affects neonatal ECFC function and elucidated the role of lncRNAs herein. Wound healing of umbilical cord blood-derived ECFCs after pregnancies with GWG <13 kg versus >13 kg was determined in a scratch assay and based on monolayer impedance after electric wounding (electric cell-substrate impedance sensing, ECIS). LncRNA expression was analysed by RNA sequencing. The function of killer cell lectin-like receptor K1 antisense RNA (KLRK1-AS1) was investigated after siRNA-based knockdown. Closure of the scratch was delayed by 25% (P = 0.041) in the higher GWG group and correlated inversely with GWG (R = -0.538, P = 0.012) in all subjects (n = 22). Similarly, recovery of the monolayer barrier after electric wounding was delayed (-11% after 20 h; P = 0.014; n = 15). Several lncRNAs correlated with maternal GWG, the most significant one being KLRK1-AS1 (log2 fold change = -0.135, P < 0.001, n = 35). KLRK1-AS1 knockdown (n = 4) reduced barrier recovery after electric wounding by 21% (P = 0.029) and KLRK1-AS1 expression correlated with the time required for wound healing for both scratch (R = 0.447, P = 0.033) and impedance-based assay (R = 0.629, P = 0.014). Higher GWG reduces wound healing of neonatal ECFCs, and lower levels of the lncRNA KLRK1-AS1 may underlie this. KEY POINTS: Maternal cardiovascular risk factors such as diabetes, obesity and smoking in pregnancy disturb fetal endothelial function, and we here investigated whether also high gestational weight gain (GWG) has an impact on fetal endothelial cells. Circulating endothelial progenitor cells (endothelial colony forming cells, ECFCs) are highly abundant in the neonatal blood stream and serve as a circulating pool for vascular growth and repair. We revealed that higher GWG delays wound healing capacity of ECFCs in vitro. We identified the regulatory RNA lncRNA KLRK1-AS1 as a link between GWG and delayed ECFC wound healing. Our data show that high GWG, independent of pre-pregnancy BMI, affects neonatal ECFC function.

Human centenarian-associated SIRT6 mutants modulate hepatocyte metabolism and collagen deposition in multilineage hepatic 3D spheroids

Non-alcoholic fatty liver disease (NAFLD), encompassing fatty liver and its progression into nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC), is one of the rapidly rising health concerns worldwide. SIRT6 is an essential nuclear sirtuin that regulates numerous pathological processes including insulin resistance and inflammation, and recently it has been implicated in the amelioration of NAFLD progression. SIRT6 overexpression protects from formation of fibrotic lesions. However, the underlying molecular mechanisms are not fully delineated. Moreover, new allelic variants of SIRT6 (N308K/A313S) were recently associated with the longevity in Ashkenazi Jews by improving genome maintenance and DNA repair, suppressing transposons and killing cancer cells. Whether these new SIRT6 variants play different or enhanced roles in liver diseases is currently unknown. In this study, we aimed to clarify how these new centenarian-associated SIRT6 genetic variants affect liver metabolism and associated diseases. We present evidence that overexpression of centenarian-associated SIRT6 variants dramatically altered the metabolomic and secretomic profiles of unchallenged immortalized human hepatocytes (IHH). Most amino acids were increased in the SIRT6 N308K/A313S overexpressing IHH when compared to IHH transfected with the SIRT6 wild-type sequence. Several unsaturated fatty acids and glycerophospholipids were increased, and ceramide tended to be decreased upon SIRT6 N308K/A313S overexpression. Furthermore, we found that overexpression of SIRT6 N308K/A313S in a 3D hepatic spheroid model formed by the co-culture of human immortalized hepatocytes (IHH) and hepatic stellate cells (LX2) inhibited collagen deposition and fibrotic gene expression in absence of metabolic or dietary challenges. Hence, our findings suggest that novel longevity associated SIRT6 N308K/A313S variants could favor the prevention of NASH by altering hepatocyte proteome and lipidome.

Role of microRNA in Endocrine Disruptor-Induced Immunomodulation of Metabolic Health

The prevalence of poor metabolic health is growing exponentially worldwide. This condition is associated with complex comorbidities that lead to a compromised quality of life. One of the contributing factors recently gaining attention is exposure to environmental chemicals, such as endocrine-disrupting chemicals (EDCs). Considerable evidence suggests that EDCs can alter the endocrine system through immunomodulation. More concerning, EDC exposure during the fetal development stage has prominent adverse effects later in life, which may pass on to subsequent generations. Although the mechanism of action for this phenomenon is mostly unexplored, recent reports implicate that non-coding RNAs, such as microRNAs (miRs), may play a vital role in this scenario. MiRs are significant contributors in post-transcriptional regulation of gene expression. Studies demonstrating the immunomodulation of EDCs via miRs in metabolic health or towards the Developmental Origins of Health and Disease (DOHaD) Hypothesis are still deficient. The aim of the current review was to focus on studies that demonstrate the impact of EDCs primarily on innate immunity and the potential role of miRs in metabolic health.

Heart failure and cancer: From active exposure to passive adaption

The human body seems like a "balance integrator." On the one hand, the body constantly actively receives various outside stimuli and signals to induce changes. On the other hand, several internal regulations would be initiated to adapt to these changes. In most cases, the body could keep the balance in vitro and in vivo to reach a healthy body. However, in some cases, the body can only get to a pathological balance. Actively exposed to unhealthy lifestyles and passively adapting to individual primary diseases lead to a similarly inner environment for both heart failure and cancer. To cope with these stimuli, the body must activate the system regulation mechanism and face the mutual interference. This review summarized the association between heart failure and cancer from active exposure to passive adaption. Moreover, we hope to inspire researchers to contemplate these two diseases from the angle of overall body consideration.

Laminar shear stress alleviates monocyte adhesion and atherosclerosis development via miR-29b-3p/CX3CL1 axis regulation

Laminar shear stress (Lss) is an important anti-atherosclerosis (anti-AS) factor, but its mechanism network is not clear. Therefore, this study aimed to identify how Lss acts against AS formation from a new perspective. In this study, we analyzed high-throughput sequencing data from static and Lss-treated human aortic and human umbilical vein endothelial cells (HAECs and HUVECs, respectively) and found that the expression of CX3CL1, which is a target gene closely related to AS development, was lower in the Lss group. Lss alleviated the inflammatory response in TNF-α (also known as TNF)-activated HAECs by regulating the miR-29b-3p/CX3CL1 axis, and this was achieved by blocking nuclear factor (NF)-κB signaling. In complementary in vivo experiments, a high-fat diet (HFD) induced inflammatory infiltration and plaque formation in the aorta, both of which were significantly reduced after injection of agomir-miRNA-29b-3p via the tail vein into HFD-fed ApoE^−/− mice. In conclusion, this study reveals that the Lss-sensitive miR-29b-3p/CX3CL1 axis is an important regulatory target that affects vascular endothelial inflammation and AS development. Our study provides new insights into the prevention and treatment of AS.

Summary: The laminar shear stress-sensitive miR-29b-3p/CX3CL1 axis significantly inhibits monocyte adhesion to activated human aortic endothelial cells, and alleviates local inflammation and plaque formation in ApoE^−/− mice fed a high-fat diet.

Cardiovascular signatures of COVID-19 predict mortality and identify barrier stabilizing therapies

Background

Endothelial cell (EC) activation, endotheliitis, vascular permeability, and thrombosis have been observed in patients with severe coronavirus disease 2019 (COVID-19), indicating that the vasculature is affected during the acute stages of SARS-CoV-2 infection. It remains unknown whether circulating vascular markers are sufficient to predict clinical outcomes, are unique to COVID-19, and if vascular permeability can be therapeutically targeted.

Methods

Prospectively evaluating the prevalence of circulating inflammatory, cardiac, and EC activation markers as well as developing a microRNA atlas in 241 unvaccinated patients with suspected SARS-CoV-2 infection allowed for prognostic value assessment using a Random Forest model machine learning approach. Subsequent ex vivo experiments assessed EC permeability responses to patient plasma and were used to uncover modulated gene regulatory networks from which rational therapeutic design was inferred.

Findings

Multiple inflammatory and EC activation biomarkers were associated with mortality in COVID-19 patients and in severity-matched SARS-CoV-2-negative patients, while dysregulation of specific microRNAs at presentation was specific for poor COVID-19-related outcomes and revealed disease-relevant pathways. Integrating the datasets using a machine learning approach further enhanced clinical risk prediction for in-hospital mortality. Exposure of ECs to COVID-19 patient plasma resulted in severity-specific gene expression responses and EC barrier dysfunction, which was ameliorated using angiopoietin-1 mimetic or recombinant Slit2-N.

Interpretation

Integration of multi-omics data identified microRNA and vascular biomarkers prognostic of in-hospital mortality in COVID-19 patients and revealed that vascular stabilizing therapies should be explored as a treatment for endothelial dysfunction in COVID-19, and other severe diseases where endothelial dysfunction has a central role in pathogenesis.

Funding Information

This work was directly supported by grant funding from the Ted Rogers Center for Heart Research, Toronto, Ontario, Canada and the Peter Munk Cardiac Center, Toronto, Ontario, Canada.

Post-Transcriptional Regulation of Molecular Determinants during Cardiogenesis

Cardiovascular development is initiated soon after gastrulation as bilateral precardiac mesoderm is progressively symmetrically determined at both sides of the developing embryo. The precardiac mesoderm subsequently fused at the embryonic midline constituting an embryonic linear heart tube. As development progress, the embryonic heart displays the first sign of left-right asymmetric morphology by the invariably rightward looping of the initial heart tube and prospective embryonic ventricular and atrial chambers emerged. As cardiac development progresses, the atrial and ventricular chambers enlarged and distinct left and right compartments emerge as consequence of the formation of the interatrial and interventricular septa, respectively. The last steps of cardiac morphogenesis are represented by the completion of atrial and ventricular septation, resulting in the configuration of a double circuitry with distinct systemic and pulmonary chambers, each of them with distinct inlets and outlets connections. Over the last decade, our understanding of the contribution of multiple growth factor signaling cascades such as Tgf-beta, Bmp and Wnt signaling as well as of transcriptional regulators to cardiac morphogenesis have greatly enlarged. Recently, a novel layer of complexity has emerged with the discovery of non-coding RNAs, particularly microRNAs and lncRNAs. Herein, we provide a state-of-the-art review of the contribution of non-coding RNAs during cardiac development. microRNAs and lncRNAs have been reported to functional modulate all stages of cardiac morphogenesis, spanning from lateral plate mesoderm formation to outflow tract septation, by modulating major growth factor signaling pathways as well as those transcriptional regulators involved in cardiac development.

Flow-Responsive Noncoding RNAs in the Vascular System: Basic Mechanisms for the Clinician

The vascular system is largely exposed to the effect of changing flow conditions. Vascular cells can sense flow and its changes. Flow sensing is of pivotal importance for vascular remodeling. In fact, it influences the development and progression of atherosclerosis, controls its location and has a major influx on the development of local complications. Despite its importance, the research community has traditionally paid scarce attention to studying the association between different flow conditions and vascular biology. More recently, a growing body of evidence has been accumulating, revealing that ncRNAs play a key role in the modulation of several biological processes linking flow-sensing to vascular pathophysiology. This review summarizes the most relevant evidence on ncRNAs that are directly or indirectly responsive to flow conditions to the benefit of the clinician, with a focus on the underpinning mechanisms and their potential application as disease biomarkers.

Mechanism of cell death of endothelial cells regulated by mechanical forces

Cell death of endothelial cells (ECs) is a common devastating consequence of various vascular-related diseases. Atherosclerosis, hypertension, sepsis, diabetes, cerebral ischemia and cardiac ischemia/reperfusion injury, and chronic kidney disease remain major causes of morbidity and mortality worldwide, in which ECs are constantly subjected to a great amount of dynamic changed mechanical forces including shear stress, extracellular matrix stiffness, mechanical stretch and microgravity. A thorough understanding of the regulatory mechanisms by which the mechanical forces controlled the cell deaths including apoptosis, autophagy, and pyroptosis is crucial for the development of new therapeutic strategies. In the present review, experimental and clinical data highlight that nutrient depletion, oxidative stress, tumor necrosis factor-α, high glucose, lipopolysaccharide, and homocysteine possess cytotoxic effects in many tissues and induce apoptosis of ECs, and that sphingosine-1-phosphate protects ECs. Nevertheless, EC apoptosis in the context of those artificial microenvironments could be enhanced, reduced or even reversed along with the alteration of patterns of shear stress. An appropriate level of autophagy diminishes EC apoptosis to some extent, in addition to supporting cell survival upon microenvironment challenges. The intervention of pyroptosis showed a profound effect on atherosclerosis. Further cell and animal studies are required to ascertain whether the alterations in the levels of cell deaths and their associated regulatory mechanisms happen at local lesion sites with considerable mechanical force changes, for preventing senescence and cell deaths in the vascular-related diseases.

Mesenchymal Stem Cells Alter MicroRNA Expression and Attenuate Thoracic Aortic Aneurysm Formation

BACKGROUND

Thoracic aortic aneurysms (TAA) are a progressive disease characterized by inflammation, smooth muscle cell activation and matrix degradation. We hypothesized that mesenchymal stem cells (MSCs) can immunomodulate vascular inflammation and remodeling via altered microRNA (miRNAs) expression profile to attenuate TAA formation.

MATERIALS AND METHODS

C57BL/6 mice underwent topical elastase application to form descending TAAs. Mice were also treated with MSCs on days 1 and 5 and aortas were analyzed on day 14 for aortic diameter. Cytokine array was performed in aortic tissue and total RNA was tagged and hybridized for miRNAs microarray analysis. Immunohistochemistry was performed for elastin degradation and leukocyte infiltration.

RESULTS

Treatment with MSCs significantly attenuated aortic diameter and TAA formation compared to untreated mice. MSC administration also attenuated T-cell, neutrophil and macrophage infiltration and prevented elastic degradation to mitigate vascular remodeling. MSC treatment also attenuated aortic inflammation by decreasing proinflammatory cytokines (CXCL13, IL-27, CXCL12 and RANTES) and upregulating anti-inflammatory interleukin-10 expression in aortic tissue of elastase-treated mice. TAA formation demonstrated activation of specific miRNAs that are associated with aortic inflammation and vascular remodeling. Our results also demonstrated that MSCs modulate a different set of miRNAs that are associated with decrease leukocyte infiltration and vascular inflammation to attenuate the aortic diameter and TAA formation.

CONCLUSIONS

These results indicate that MSCs immunomodulate specific miRNAs that are associated with modulating hallmarks of aortic inflammation and vascular remodeling of aortic aneurysms. Targeted therapies designed using MSCs and miRNAs have the potential to regulate the growth and development of TAAs.

Mechanisms underlying unidirectional laminar shear stress-mediated Nrf2 activation in endothelial cells: Amplification of low shear stress signaling by primary cilia

Endothelial cells are sensitive to mechanical stress and respond differently to oscillatory flow versus unidirectional flow. This review highlights the mechanisms by which a wide range of unidirectional laminar shear stress induces activation of the redox sensitive antioxidant transcription factor nuclear factor-E2-related factor 2 (Nrf2) in cultured endothelial cells. We propose that fibroblast growth factor-2 (FGF-2), brain-derived neurotrophic factor (BDNF) and 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) are potential Nrf2 activators induced by laminar shear stress. Shear stress-dependent secretion of FGF-2 and its receptor-mediated signaling is tightly controlled, requiring neutrophil elastase released by shear stress, αvβ3 integrin and the cell surface glycocalyx. We speculate that primary cilia respond to low laminar shear stress (<10 dyn/cm2), resulting in secretion of insulin-like growth factor 1 (IGF-1), which facilitates αvβ3 integrin-dependent FGF-2 secretion. Shear stress induces generation of heparan-binding epidermal growth factor-like growth factor (HB-EGF), which contributes to FGF-2 secretion and gene expression. Furthermore, HB-EGF signaling modulates FGF-2-mediated NADPH oxidase 1 activation that favors casein kinase 2 (CK2)-mediated phosphorylation/activation of Nrf2 associated with caveolin 1 in caveolae. Higher shear stress (>15 dyn/cm2) induces vesicular exocytosis of BDNF from endothelial cells, and we propose that BDNF via the p75NTR receptor could induce CK2-mediated Nrf2 activation. Unidirectional laminar shear stress upregulates gene expression of FGF-2 and BDNF and generation of 15d-PGJ2, which cooperate in sustaining Nrf2 activation to protect endothelial cells against oxidative damage.

Tie2 activation protects against prothrombotic endothelial dysfunction in COVID-19

Profound endothelial dysfunction accompanies the microvascular thrombosis commonly observed in severe COVID-19. In the quiescent state, the endothelial surface is anticoagulant, a property maintained at least in part via constitutive signaling through the Tie2 receptor. During inflammation, the Tie2 antagonist angiopoietin-2 (Angpt-2) is released from activated endothelial cells and inhibits Tie2, promoting a prothrombotic phenotypic shift. We sought to assess whether severe COVID-19 is associated with procoagulant dysfunction of the endothelium and alterations in the Tie2-angiopoietin axis. Primary human endothelial cells treated with plasma from patients with severe COVID-19 upregulated the expression of thromboinflammatory genes, inhibited expression of antithrombotic genes, and promoted coagulation on the endothelial surface. Pharmacologic activation of Tie2 with the small molecule AKB-9778 reversed the prothrombotic state induced by COVID-19 plasma in primary endothelial cells. On lung autopsy specimens from COVID-19 patients, we found a prothrombotic endothelial signature as evidenced by increased von Willebrand Factor and loss of anticoagulant proteins. Assessment of circulating endothelial markers in a cohort of 98 patients with mild, moderate, or severe COVID-19 revealed profound endothelial dysfunction indicative of a prothrombotic state. Angpt-2 concentrations rose with increasing disease severity and highest levels were associated with worse survival. These data highlight the disruption of Tie2-angiopoietin signaling and procoagulant changes in endothelial cells in severe COVID-19. Moreover, our findings provide novel rationale for current trials of Tie2 activating therapy with AKB-9778 in severe COVID-19 disease.

MiR-137 regulates low-intensity shear stress-induced human aortic endothelial cell apoptosis via JNK/AP-1 signaling

The objective of this study is to evaluate the role of miR-137 in low-intensity shear stress-induced endoplasmic reticulum (ER) stress and cell apoptosis in human aortic endothelial cells (HAECs). HAECs were transfected with miR-137 mimic, miR-137 inhibitor, or the corresponding negative control and then exposed to pulsatile shear stress in a parallel-plate flow chamber at 1, 2, 5, 10, and 15 dyn/cm² for 3 h. Real-time polymerase chain reaction was used to detect mRNA expression of miR-137 and SDS22. A dual-luciferase reporter assay was employed to verify the direct interaction between miR-137 and SDS22. The internal morphology of cells and cell apoptosis was assessed by TUNEL staining observed under a transmission electron microscope. Meanwhile, the protein expression of oxidative stress-related, apoptosis-related, and activated c-Jun N-terminal kinase (JNK)/activator protein-1 (AP-1) signaling-related genes were analyzed by western blotting. Low strength shear stress (0-5 dyn/cm²) caused a negative change of HAEC surface and internal morphology in an intensity-dependent manner, and these changes were gradually weakened when shear stress was increased more than 5 dyn/cm². Furthermore, low-intensity shear stress promoted oxidative stress response, accelerated cell apoptosis, and upregulated miR-137 expression and JNK/AP-1 signaling in HAECs. MiR-137 directly targets SDS22. Knockdown of miR-137 noticeably reduced activation of JNK/AP-1 signaling, oxidative stress response, and cell apoptosis induced by shear stress. MiR-137 regulated low-intensity shear stress-induced human aortic endothelial cell ER stress and cell apoptosis via JNK/AP-1 signaling.

Mechanoresponsive Smad5 Enhances MiR-487a Processing to Promote Vascular Endothelial Proliferation in Response to Disturbed Flow

MicroRNAs (miRs) and bone morphogenetic protein receptor-specific Smads are mechano-responsive molecules that play vital roles in modulating endothelial cell (EC) functions in response to blood flow. However, the roles of interplay between these molecules in modulating EC functions under flows remain unclear. We elucidated the regulatory roles of the interplay between miR-487a and Smad5 in EC proliferation in response to different flow patterns. Microarray and quantitative RT-PCR showed that disturbed flow with low and oscillatory shear stress (OS, 0.5 ± 4 dynes/cm²) upregulates EC miR-487a in comparison to static controls and pulsatile shear stress (12 ± 4 dynes/cm²). MiR-487a expression was higher in ECs in the inner curvature (OS region) than the outer curvature of the rat aortic arch and thoracic aorta and also elevated in diseased human coronary arteries. MiR-487a expression was promoted by nuclear phospho-Smad5, which bound to primary-miR-487a to facilitate miR-487a processing. Algorithm prediction and luciferase reporter and argonaute 2-immunoprecipitation assays demonstrated that miR-487a binds to 3'UTR of CREB binding protein (CBP) and p53. Knockdown and overexpression of miR-487a decreased and increased, respectively, phospho-Rb and cyclin A expressions through CBP and p53. A BrdU incorporation assay showed that miR-487a enhanced EC proliferation under OS in vitro and in disturbed flow regions of experimentally stenosed rat abdominal aorta in vivo. These results demonstrate that disturbed flow with OS induces EC expression of miR-487a through its enhanced processing by activated-Smad5. MiR-487 inhibits its direct targets CBP and p53 to induce EC cycle progression and proliferation. Our findings suggest that EC miR-487 may serve as an important molecular target for intervention against disturbed flow-associated vascular disorders resulting from atherosclerosis.

Activation of GPR30 with G1 inhibits oscillatory shear stress-induced adhesion of THP-1 monocytes to HAECs by increasing KLF2

Atherosclerosis is a chronic inflammatory disease known to be mediated by numerous factors, among which endothelial dysfunction plays a critical role. Oscillatory shear stress induces endothelial cells to lose their anti-atherosclerotic properties and downregulates the expression of the innate protective transcription factor, Krüppel-like factor 2 (KLF2), which is typically upregulated in vascular endothelial cells in response to harmful stimuli. Oxidative stress and inflammation impair endothelial function and damage their survival. Oscillatory shear stress also promotes generation of reactive oxygen species and production of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), thereby further promoting endothelial dysfunction and formation of atherosclerotic plaque. A major event in the development of atherosclerotic plaque is rolling and adhesion of monocytes to endothelial cells, which is mediated by adhesion molecules including vascular cellular adhesion molecule 1 and endothelial-selectin. Expression of these molecules is also upregulated by oscillatory shear stress. Estrogen has long been recognized as a protective agent against atherosclerosis, but the mechanisms through which estrogen receptors prevent atherogenesis remain unclear. In the present study, we investigated the role of the G-coupled protein estrogen receptor (GPR30) in oscillatory shear stress- induced endothelial dysfunction. We show that agonism of GPR30 by its specific agonist G1 prevented oscillatory shear stress -induced oxidative stress markers and production of inflammatory cytokines and adhesion molecules. As a result, GPR30 activation suppresses monocytes adhesion to endothelial cells. Furthermore, we demonstrate that GPR30 prevents oscillatory shear stress- induced downregulation of KLF2 via ERK5 pathway. These findings suggest that endothelial GPR30 is potential target to suppress oscillatory shear stress mediated atherogenesis.

A Comprehensive miRNome Analysis of Macrophages Isolated from db/db Mice and Selected miRNAs Involved in Metabolic Syndrome-Associated Cardiac Remodeling

Cardiac macrophages are known from various activities, therefore we presume that microRNAs (miRNAs) produced or released by macrophages in cardiac tissue have impact on myocardial remodeling in individuals with metabolic syndrome (MetS). We aim to assess the cardiac macrophage miRNA profile by selecting those miRNA molecules that potentially exhibit regulatory functions in MetS-related cardiac remodeling. Cardiac tissue macrophages from control and db/db mice (an animal model of MetS) were counted and sorted with flow cytometry, which yielded two populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Total RNA was then isolated, and miRNA expression profiles were evaluated with Next Generation Sequencing. We successfully sequenced 1400 miRNAs in both macrophage populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Among the 1400 miRNAs, about 150 showed different expression levels in control and db/db mice and between these two subpopulations. At least 15 miRNAs are possibly associated with MetS pathology in cardiac tissue due to direct or indirect regulation of the expression of miRNAs for proteins involved in angiogenesis, fibrosis, or inflammation. In this paper, for the first time we describe the miRNA transcription profile in two distinct macrophage populations in MetS-affected cardiac tissue. Although the results are preliminary, the presented data provide a foundation for further studies on intercellular cross-talk/molecular mechanism(s) involved in the regulation of MetS-related cardiac remodeling.

miRNAs: Critical mediators of breast cancer metastatic programming

MicroRNA mediated aberrant gene regulation has been implicated in several diseases including cancer. Recent research has highlighted the role of epigenetic modulation of the complex process of breast cancer metastasis by miRNAs. miRNAs play a crucial role in the process of metastatic evolution by facilitating alterations in the phenotype of tumor cells and the tumor microenvironment that promote this process. They act as critical determinants of the multi-step progression starting from carcinogenesis all the way to organotropism. In this review, we focus on the current understanding of the compelling role of miRNAs in breast cancer metastasis.

Juglanin suppresses oscillatory shear stress-induced endothelial dysfunction: An implication in atherosclerosis

INTRODUCTION

Atherosclerosis is characterized by endothelial cell dysfunction followed by lesion formation, arterial stenosis, potentially arterial occlusion, and severe outcomes. Novel treatments to slow or prevent the progression of the disease are of considerable clinical value. In the present study, we investigated the potential anti-atherosclerotic effects of the natural product juglanin in oscillatory shear stress (OSS) exposed endothelial cells.

METHODS

Human aortic endothelial cells (HAECs) were exposed to OSS generated by a micro fluidal Teflon cone at 1 Hz frequency cycles (±5 dyn/cm²) in the presence or absence of 2.5 and 5 μM juglanin for 24 h. The expression levels of inflammatory factors and vascular adhesion molecules were evaluated using qRT-PCR, Western Blot, and ELISA. DHE assay was used to detect the production of ROS. The monocytic THP-1 cells were labeled with calcein-AM and incubated with HAECs for adhesion assay.

RESULTS

Juglanin reduces OSS-induced oxidative stress by reducing the production of ROS through downregulation of NOX-2 and rescuing OSS-induced reduced expression of eNOS. Juglanin also inhibits the inflammatory response by suppressing OSS-induced expressions of IL-1β, MCP-1, and HMGB1. Using THP-1 monocytes, we show that juglanin reduces the attachment of monocytes to endothelial cells by inhibiting the expression of VCAM-1 and E-selectin. Moreover, Juglanin rescues OSS-reduced expression of atheroprotective transcriptional factor KLF2.

CONCLUSIONS

Our findings indicate that juglanin protects against various atheroprone OSS-induced endothelial dysfunction. Juglanin has potential implication as a candidate for vascular intervention of atherosclerosis.

Overview of Crosstalk Between Multiple Factor of Transcytosis in Blood Brain Barrier

Blood brain barrier (BBB) conserves unique regulatory system to maintain barrier tightness while allowing adequate transport between neurovascular units. This mechanism possess a challenge for drug delivery, while abnormality may result in pathogenesis. Communication between vascular and neural system is mediated through paracellular and transcellular (transcytosis) pathway. Transcytosis itself showed dependency with various components, focusing on caveolae-mediated. Among several factors, intense communication between endothelial cells, pericytes, and astrocytes is the key for a normal development. Regulatory signaling pathway such as VEGF, Notch, S1P, PDGFβ, Ang/Tie, and TGF-β showed interaction with the transcytosis steps. Recent discoveries showed exploration of various factors which has been proven to interact with one of the process of transcytosis, either endocytosis, endosomal rearrangement, or exocytosis. As well as providing a hypothetical regulatory pathway between each factors, specifically miRNA, mechanical stress, various cytokines, physicochemical, basement membrane and junctions remodeling, and crosstalk between developmental regulatory pathways. Finally, various hypotheses and probable crosstalk between each factors will be expressed, to point out relevant research application (Drug therapy design and BBB-on-a-chip) and unexplored terrain.

Environmental Influencers, MicroRNA, and Multiple Sclerosis

Multiple sclerosis (MS) is a complex neurological disorder characterized by an aberrant immune system that affects patients' quality of life. Several environmental factors have previously been proposed to associate with MS pathophysiology, including vitamin D deficiency, Epstein-Barr virus (EBV) infection, and cigarette smoking. These factors may influence cellular molecularity, interfering with cellular proliferation, differentiation, and apoptosis. This review argues that small noncoding RNA named microRNA (miRNA) influences these factors' mode of action. Dysregulation in the miRNAs network may deeply impact cellular hemostasis, thereby possibly resulting in MS pathogenicity. This article represents a literature review and an author's theory of how environmental factors may induce dysregulations in the miRNAs network, which could ultimately affect MS pathogenicity.

Metformin shows anti-inflammatory effects in murine macrophages through Dicer/microribonucleic acid-34a-5p and microribonucleic acid-125b-5p

AIMS/INTRODUCTION

Metformin, a widely prescribed antidiabetic agent, has been shown to exhibit anti-inflammatory effects in obese and type 2 diabetes patients, but the mechanism is not well elucidated. Microribonucleic acids (miRNAs) are a group of small non-coding ribonucleic acids that participate in many biological and pathological processes. The aim of the present study was to investigate whether Dicer, a key miRNA biogenesis enzyme, and miRNAs in macrophages are implicated in the anti-inflammatory effects of metformin.

MATERIALS AND METHODS

Enzyme-linked immunosorbent assay and reverse transcription quantitative polymerase chain reaction were carried out to verify the anti-inflammatory effects of metformin. miRNA microarray was applied to detect the expression profile of miRNA. Western-blotting, enzyme-linked immunosorbent assay and reverse transcription quantitative polymerase chain reaction were used to examine the role Dicer and miRNAs play in the anti-inflammatory effects of metformin.

RESULTS

In parallel with the suppression of interleukin-6 and tumor necrosis factor-α production in resting and lipopolysaccharide-stimulated macrophages, metformin could induce an increase in Dicer and most miRNAs. When Dicer was knocked down, the anti-inflammatory effects of metformin were significantly attenuated. Additionally, the upregulation of miRNA (miR)-34a-5p and miR-125b-5p by metformin were also blunted in Dicer knockdown macrophages. Furthermore, inhibition of miR-34a-5p and miR-125b-5p could impair the suppressive action of metformin on pro-inflammatory factors production, whereas overexpression of the two miRNAs mimicked the anti-inflammatory effects of metformin.

CONCLUSIONS

Metformin might show anti-inflammatory effects in macrophages through the induction of Dicer and the subsequent upregulation of miR-34a-5p and miR-125b-5p.

The microRNA in ventricular remodeling: the miR-30 family

Ventricular remodeling (VR) is a complex pathological process of cardiomyocyte apoptosis, cardiac hypertrophy, and myocardial fibrosis, which is often caused by various cardiovascular diseases (CVDs) such as hypertension, acute myocardial infarction, heart failure (HF), etc. It is also an independent risk factor for a variety of CVDs, which will eventually to damage the heart function, promote cardiovascular events, and lead to an increase in mortality. MicroRNAs (miRNAs) can participate in a variety of CVDs through post-transcriptional regulation of target gene proteins. Among them, microRNA-30 (miR-30) is one of the most abundant miRNAs in the heart. In recent years, the study found that the miR-30 family can participate in VR through a variety of mechanisms, including autophagy, apoptosis, oxidative stress, and inflammation. VR is commonly found in ischemic heart disease (IHD), hypertensive heart disease (HHD), diabetic cardiomyopathy (DCM), antineoplastic drug cardiotoxicity (CTX), and other CVDs. Therefore, we will review the relevant mechanisms of the miR-30 in VR induced by various diseases.

MicroRNA-30-3p Suppresses Inflammatory Factor-Induced Endothelial Cell Injury by Targeting TCF21

Atherosclerosis is one of the leading causes of mortality worldwide. Growing evidence suggested that miRNAs contributed to the progression of atherosclerosis. miR-30-5p was found involved in various diseases. However, the role of miR-30-5p in regulation of atherosclerosis is not known. Here, we aim to investigate the effects of miR-30-5p on regulating the progression of atherosclerosis. The expression levels of miR-30-5p in serum collected from atherosclerosis patients and normal healthy people were analyzed by qRT-PCR. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway bioinformatics were carried out to reveal the possible signaling pathways involved in the mode of action of miR-30-5p. A potential target gene of miRNA-30-5p was searched and examined by a luciferase reporter assay. ELISA, Western blot, proliferation, and flow cytometry assays were performed to assess the biological functional role of miR-30-5p in vitro. Also, an in vitro monocyte-endothelial cell coculture model was used to study the functional role of miR-30-5p in atherosclerosis. We found that miR-30-5p was significantly decreased in serum samples from atherosclerosis patients compared with control subjects. GO and KEGG analysis results showed that miR-30-5p is highly associated with genetic profile of cardiovascular disease. TCF21 was verified as a target gene of miR-30-5p. Overexpression of miR-30-5p in THP-1 not only protected endothelial cell viability but also inhibited endothelial cell apoptosis, and similar results were observed in cells with that of TCF21 knocked down. Moreover, miR-30-5p decreased the expression levels of lactate dehydrogenase (LDH) and tumor necrosis factor-α (TNF-α) and reduced reactive oxygen species (ROS) accumulation. NF-κB and MAPK/p38 pathways played an indispensable role in the protection ability of miR-30-5p against atherosclerosis. Our results reveal that miR-30-5p suppresses the progression of atherosclerosis through targeting TCF21 in vitro. Therefore, the miR-30-5p-TCF21-MAPK/p38 signaling pathway may be a potential biomarker or therapeutic target in atherosclerosis.

Exosomes: An emerging factor in atherosclerosis

Atherosclerosis is the main reason for morbidity and death caused by cardiovascular disease which leads to approximately 20% of total death around the world. Exosomes secreted by the cells is a kind of extracellular vesicles with lipid bilayer structure, containing a variety of cell specific lipid, nucleic acid and protein, involved in intercellular communication, plays an important role in different physiological and pathological process. In recent years, with the deepening of research, the role of exosomes in cardiovascular diseases has received extensive attention. This review summarizes the roles of exosomes and exosome-derived from microRNAs, proteins and DNA as biomarkers in the development of atherosclerosis, and explores the mechanism of exosome-mediated intercellular crosstalk in atherosclerosis, providing potential roles for diagnosis and treatment.

Non-genomic Effects of Estrogen on Cell Homeostasis and Remodeling With Special Focus on Cardiac Ischemia/Reperfusion Injury

This review takes into consideration the main mechanisms involved in cellular remodeling following an ischemic injury, with special focus on the possible role played by non-genomic estrogen effects. Sex differences have also been considered. In fact, cardiac ischemic events induce damage to different cellular components of the heart, such as cardiomyocytes, vascular cells, endothelial cells, and cardiac fibroblasts. The ability of the cardiovascular system to counteract an ischemic insult is orchestrated by these cell types and is carried out thanks to a number of complex molecular pathways, including genomic (slow) or non-genomic (fast) effects of estrogen. These pathways are probably responsible for differences observed between the two sexes. Literature suggests that male and female hearts, and, more in general, cardiovascular system cells, show significant differences in many parameters under both physiological and pathological conditions. In particular, many experimental studies dealing with sex differences in the cardiovascular system suggest a higher ability of females to respond to environmental insults in comparison with males. For instance, as cells from females are more effective in counteracting the ischemia/reperfusion injury if compared with males, a role for estrogen in this sex disparity has been hypothesized. However, the possible involvement of estrogen-dependent non-genomic effects on the cardiovascular system is still under debate. Further experimental studies, including sex-specific studies, are needed in order to shed further light on this matter.

MicroRNA-30a as a candidate underlying sex-specific differences in neonatal hyperoxic lung injury: implications for BPD

Premature male neonates are at a greater risk of developing bronchopulmonary dysplasia (BPD). The reasons underlying sexually dimorphic outcomes in premature neonates are not known. The role of miRNAs in mediating sex biases in BPD is understudied. Analysis of the pulmonary transcriptome revealed that a large percentage of angiogenesis-related differentially expressed genes are miR-30a targets. We tested the hypothesis that there is differential expression of miR-30a in vivo and in vitro in neonatal human pulmonary microvascular endothelial cells (HPMECs) upon exposure to hyperoxia. Neonatal male and female mice (C57BL/6) were exposed to hyperoxia [95% fraction of inspired oxygen (FiO2), postnatal day ( PND) 1-5] and euthanized on PND 7 and 21. HPMECs (18-24-wk gestation donors) were subjected to hyperoxia (95% O2 and 5% CO2) or normoxia (air and 5% CO2) up to 72 h. miR-30a expression was increased in both males and females in the acute phase ( PND 7) after hyperoxia exposure. However, at PND 21 (recovery phase), female mice showed significantly higher miR-30a expression in the lungs compared with male mice. Female HPMECs showed greater expression of miR-30a in vitro upon exposure to hyperoxia. Delta-like ligand 4 (Dll4) was an miR-30a target in HPMECs and showed sex-specific differential expression. miR-30a increased angiogenic sprouting in vitro in female HPMECs. Lastly, we show decreased expression of miR-30a and increased expression of DLL4 in human BPD lung samples compared with controls. These results support the hypothesis that miR-30a could, in part, contribute to the sex-specific molecular mechanisms in play that lead to the sexual dimorphism in BPD.

Role of miRNA in the Regulatory Mechanisms of Estrogens in Cardiovascular Ageing

Cardiovascular diseases are a worldwide health problem and are the leading cause of mortality in developed countries. Together with experimental data, the lower incidence of cardiovascular diseases in women than in men of reproductive age points to the influence of sex hormones at the cardiovascular level and suggests that estrogens play a protective role against cardiovascular disease and that this role is also modified by ageing. Estrogens affect cardiovascular function via their specific estrogen receptors to trigger gene expression changes at the transcriptional level. In addition, emerging studies have proposed a role for microRNAs in the vascular effects mediated by estrogens. miRNAs regulate gene expression by repressing translational processes and have been estimated to be involved in the regulation of approximately 30% of all protein-coding genes in mammals. In this review, we highlight the current knowledge of the role of estrogen-sensitive miRNAs, and their influence in regulating vascular ageing.

Endothelial Activation: The Ang/Tie Axis in Sepsis

Sepsis, a dysregulated host response to infection that causes life-threatening organ dysfunction, is a highly heterogeneous syndrome with no specific treatment. Although sepsis can be caused by a wide variety of pathogenic organisms, endothelial dysfunction leading to vascular leak is a common mechanism of injury that contributes to the morbidity and mortality associated with the syndrome. Perturbations to the angiopoietin (Ang)/Tie2 axis cause endothelial cell activation and contribute to the pathogenesis of sepsis. In this review, we summarize how the Ang/Tie2 pathway is implicated in sepsis and describe its prognostic as well as therapeutic utility in life-threatening infections.

Endothelial microRNAs regulating the NF-κB pathway and cell adhesion molecules during inflammation

The surface of endothelial cells is covered with cell adhesion molecules, including E-selectin, intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM- 1) , that mediate the adhesion and extravasation of leukocytes and play pivotal roles in inflammatory response. microRNAs (miRNAs) regulate the expression of these important cell adhesion molecules through two distinct major mechanisms, namely via modulating the proinflammatory NF-κB pathway, which controls their transcription, and via directly targeting them. The present review highlights the role of various miRNAs in controlling the expression of E-selectin, ICAM-1, and VCAM-1: a type of regulation that can be harnessed for therapeutic prevention of inflammation-associated diseases such as atherosclerosis and sepsis. The roles of secreted miRNAs as paracrine regulators, and cell adhesion molecule-based miRNA delivery are also addressed.-Zhong, L., Simard, M. J., Huot, J. Endothelial microRNAs regulating the NF-κB pathway and cell adhesion molecules during inflammation.

p38 activation induces production of miR-146a and miR-31 to repress E-selectin expression and inhibit transendothelial migration of colon cancer cells

Extravasation of circulating cancer cells determines their metastatic potential. This process is initiated by the adhesion of cancer cells to vascular endothelial cells through specific interactions between endothelial adhesion receptors such as E-selectin and their ligands on cancer cells. In the present study, we show that miR-146a and miR-181b impede the expression of E-selectin by repressing the activity of its transcription factor NF-κB, thereby impairing the metastatic potentials of colon cancer cells by decreasing their adhesion to, and migration through, the endothelium. Among the two microRNAs, only miR-146a is activated by IL-1β, through the activation of p38, ERK and JNK MAP kinases, as well as their downstream transcription factors GATA2, c-Fos and c-Jun. Inhibiting p38 MAP kinase increases NF-κB activity, at least partially via miR-146a. Inhibiting p38 also increases the expression of E-selectin at the post-transcriptional level via decreasing miR-31, which targets E-selectin mRNA and also depends on p38 for its expression. In response to IL-1β, p38 MAP kinase hence represses the expression of E-selectin at the transcriptional and the post-transcriptional levels, via miR-146a and miR-31, respectively. These results highlight novel mechanisms by which p38 downregulates the expression of E-selectin through different microRNAs following inflammatory stimuli associated to cancer progression.

Mechanobiology in vascular remodeling

Vascular remodeling is a common pathological process in cardiovascular diseases and includes changes in cell proliferation, apoptosis and differentiation as well as vascular homeostasis. Mechanical stresses, such as shear stress and cyclic stretch, play an important role in vascular remodeling. Vascular cells can sense the mechanical factors through cell membrane proteins, cytoskeletons and nuclear envelope proteins to initiate mechanotransduction, which involves intercellular signaling, gene expression, and protein expression to result in functional regulations. Non-coding RNAs, including microRNAs and long non-coding RNAs, are involved in the regulation of vascular remodeling processes. Mechanotransduction triggers a cascade reaction process through a complicated signaling network in cells. High-throughput technologies in combination with functional studies targeting some key hubs and bridging nodes of the network can enable the prioritization of potential targets for subsequent investigations of clinical translation. Vascular mechanobiology, as a new frontier field of biomechanics, searches for principles of stress-growth in vasculature to elucidate how mechanical factors induce biological effects that lead to vascular remodeling, with the goal of understanding the mechanical basis of the pathological mechanism of cardiovascular diseases at the cellular and molecular levels. Vascular mechanobiology will play a unique role in solving the key scientific problems of human physiology and disease, as well as generating important theoretical and clinical results.

Interleukin 1β polymorphism and serum level are associated with pediatric asthma

BACKGROUND AND AIM

Interleukin-1 is a pro-inflammatory cytokine found in two forms (α and β). The α form is mainly cell-bound, whereas IL-1β is primarily secreted by macrophages in response to immune system stimulation. We hypothesized that polymorphic variants of interleukin 1 genes may play a role in childhood asthma risk. The aim of this study was to investigate if IL-1α and β polymorphism is associated with asthma in a pediatric population and if the genotype affects its serum level.

METHODS

The studied population included 310 children aged 6-18 years old (152 with asthma and 158 healthy children). Genotypes were determined with real-time PCR method using TaqMan Genotyping Assays. Serum level was measured with ELISA Set. Statistical analysis was done in Statistica v.12.0. Linkage disequilibrium and haplotype analysis was done in Haploview v. 4.2.

RESULTS

We found that three IL-1β polymorphisms rs1143634, rs1143633, and rs1143643 were associated with allergic asthma risk (P = 0.034; OR = 1.523; P = 0.024, OR = 1.477; 0.044, OR = 1.420, respectively). We also found a strong linkage disequilibrium between these polymorphisms and CAC haplotype was associated significantly with asthma risk (P = 0.023). For IL1α, we did not observe association with asthma. We then analyzed if IL-1β expression was altered in serum and we found that asthmatic children showed significantly higher IL-1β levels than healthy controls (P = 0.047). No association with asthma was observed for IL-1 α variants.

CONCLUSIONS

This study indicates that IL-1β gene polymorphism may affect allergic asthma risk in children.

Inflammatory Markers for Arterial Stiffness in Cardiovascular Diseases

Arterial stiffness predicts an increased risk of cardiovascular events. Inflammation plays a major role in large arteries stiffening, related to atherosclerosis, arteriosclerosis, endothelial dysfunction, smooth muscle cell migration, vascular calcification, increased activity of metalloproteinases, extracellular matrix degradation, oxidative stress, elastolysis, and degradation of collagen. The present paper reviews main mechanisms explaining the crosstalk between inflammation and arterial stiffness and the most common inflammatory markers associated with increased arterial stiffness, considering the most recent clinical and experimental studies. Diverse studies revealed significant correlations between the severity of arterial stiffness and inflammatory markers, such as white blood cell count, neutrophil/lymphocyte ratio, adhesion molecules, fibrinogen, C-reactive protein, cytokines, microRNAs, and cyclooxygenase-2, in patients with a broad variety of diseases, such as metabolic syndrome, diabetes, coronary heart disease, peripheral arterial disease, malignant and rheumatic disorders, polycystic kidney disease, renal transplant, familial Mediterranean fever, and oral infections, and in women with preeclampsia or after menopause. There is strong evidence that inflammation plays an important and, at least, partly reversible role in the development of arterial stiffness, and inflammatory markers may be useful additional tools in the assessment of the cardiovascular risk in clinical practice. Combined assessment of arterial stiffness and inflammatory markers may improve non-invasive assessment of cardiovascular risk, enabling selection of high-risk patients for prophylactic treatment or more regular medical examination. Development of future destiffening therapies may target pro-inflammatory mechanisms.

Immune regulation of miR-30 on the Mycobacterium tuberculosis-induced TLR/MyD88 signaling pathway in THP-1 cells

The present study aimed to examine the expression of microRNA (miR)-30 family members in THP-1 human monocytes cells during Mycobacterium tuberculosis (MTB) H37Rv infection, and to investigate the role of miR-30 in the regulation of MTB-induced Toll-like receptor (TLR)/myeloid differentiation factor 88 (MyD88) activation and cytokine expression. The THP-1 cells were infected with MTB H37Rv and the expression of miR-30 family members was determined by reverse transcription-quantitative polymerase chain reaction analysis. In addition, miR-30a and miR-30e mimics were transfected into THP-1 cells to overexpress miR-30a and miR-30e. The expression of TLR2, TLR4 and MyD88 was determined by western blot analysis, and the expression of the cytokines tumor necrosis factor-α, interleukin (IL)-6, and IL-8 was determined using ELISA assays. A luciferase reporter assay was used to identify the target gene of miR-30a. MTB infection was demonstrated to significantly induce miR-30a and miR-30e expression in THP-1 cells in a time-dependent manner. Forced overexpression of miR-30a, but not miR-30e, exhibited an inhibitory effect on TLR/MyD88 activation and cytokine expression in the uninfected and MTB-infected THP-1 cells. The luciferase reporter assay demonstrated that miR-30a directly regulates the transcriptional activity of the MyD88 3'-untranslated region. In conclusion, the present study, to the best of our knowledge, is the first to demonstrate that miR-30a suppresses TLR/MyD88 activation and cytokine expression in THP-1 cells during MTB H37Rv infection, and that MyD88 is a direct target of miR-30a. The current study may aid in the development of novel therapeutic approaches for treating MTB.

Angiopoietin-Tie signalling in the cardiovascular and lymphatic systems

Endothelial cells that form the inner layer of blood and lymphatic vessels are important regulators of vascular functions and centrally involved in the pathogenesis of vascular diseases. In addition to the vascular endothelial growth factor (VEGF) receptor pathway, the angiopoietin (Ang)-Tie system is a second endothelial cell specific ligand-receptor signalling system necessary for embryonic cardiovascular and lymphatic development. The Ang-Tie system also regulates postnatal angiogenesis, vessel remodelling, vascular permeability and inflammation to maintain vascular homoeostasis in adult physiology. This system is implicated in numerous diseases where the vasculature has an important contribution, such as cancer, sepsis, diabetes, atherosclerosis and ocular diseases. Furthermore, mutations in the TIE2 signalling pathway cause defects in vascular morphogenesis, resulting in venous malformations and primary congenital glaucoma. Here, we review recent advances in the understanding of the Ang-Tie signalling system, including cross-talk with the vascular endothelial protein tyrosine phosphatase (VE-PTP) and the integrin cell adhesion receptors, focusing on the Ang-Tie system in vascular development and pathogenesis of vascular diseases.

Exosome-Mediated miR-155 Transfer from Smooth Muscle Cells to Endothelial Cells Induces Endothelial Injury and Promotes Atherosclerosis

The vascular response to pro-atherosclerotic factors is a multifactorial process involving endothelial cells (ECs), macrophages (MACs), and smooth muscle cells (SMCs), although the mechanism by which these cell types communicate with each other in response to environmental cues is yet to be understood. Here, we show that miR-155, which is significantly expressed and secreted in Krüppel-like factor 5 (KLF5)-overexpressing vascular smooth muscle cells (VSMCs), is a potent regulator of endothelium barrier function through regulating endothelial targeting tight junction protein expression. VSMCs-derived exosomes mediate the transfer of KLF5-induced miR-155 from SMCs to ECs, which, in turn, destroys tight junctions and the integrity of endothelial barriers, leading to an increased endothelial permeability and enhanced atherosclerotic progression. Moreover, overexpression of miR-155 in ECs inhibits endothelial cell proliferation/migration and re-endothelialization in vitro and in vivo and thus increases vascular endothelial permeability. Blockage of the exosome-mediated transfer of miR-155 between these two cells may serve as a therapeutic target for atherosclerosis.

Therapeutic targeting of the angiopoietin-TIE pathway

The endothelial angiopoietin (ANG)-TIE growth factor receptor pathway regulates vascular permeability and pathological vascular remodelling during inflammation, tumour angiogenesis and metastasis. Drugs that target the ANG-TIE pathway are in clinical development for oncological and ophthalmological applications. The aim is to complement current vascular endothelial growth factor (VEGF)-based anti-angiogenic therapies in cancer, wet age-related macular degeneration and macular oedema. The unique function of the ANG-TIE pathway in vascular stabilization also renders this pathway an attractive target in sepsis, organ transplantation, atherosclerosis and vascular complications of diabetes. This Review covers key aspects of the function of the ANG-TIE pathway in vascular disease and describes the recent development of novel therapeutics that target this pathway.

Shear stress-regulated miR-27b controls pericyte recruitment by repressing SEMA6A and SEMA6D

AIMS

Vessel maturation involves the recruitment of mural cells such as pericytes and smooth muscle cells. Laminar shear stress is a major trigger for vessel maturation, but the molecular mechanisms by which shear stress affects recruitment of pericytes are unclear. MicroRNAs (miRs) are small non-coding RNAs, which post-transcriptionally control gene expression. The aim of the present study was to unveil the mechanism by which shear stress-regulated microRNAs contribute to vessel maturation.

METHODS AND RESULTS

Here, we show that laminar shear stress increased miR-27a and miR-27b expression in vitro and in ex vivo in mouse femoral artery explants. Overexpression of miR-27b in endothelial cells increased pericyte adhesion and pericyte recruitment in vitro. In vitro barrier function of endothelial-pericyte co-cultures was augmented by miR-27b overexpression, whereas inhibition of miR-27a/b reduced adhesion and pericyte coverage and decreased barrier functions. In vivo, pharmacological inhibition of miR-27a/b by locked nucleic acid antisense oligonucleotides significantly reduced pericyte coverage and increased water content in the murine uterus. MiR-27b overexpression repressed semaphorins (SEMA), which mediate repulsive signals, and the vessel destabilizing human but not mouse Angiopoietin-2 (Ang-2). Silencing of SEMA6A and SEMA6D rescued the reduced pericyte adhesion by miR-27 inhibition. Furthermore, inhibition of SEMA6D increased barrier function of an endothelial-pericyte co-culture in vitro.

CONCLUSION

The present study demonstrates for the first time that shear stress-regulated miR-27b promotes the interaction of endothelial cells with pericytes, partly by repressing SEMA6A and SEMA6D.

Function, Role, and Clinical Application of MicroRNAs in Vascular Aging

Vascular aging, a specific type of organic aging, is related to age-dependent changes in the vasculature, including atherosclerotic plaques, arterial stiffness, fibrosis, and increased intimal thickening. Vascular aging could influence the threshold, process, and severity of various cardiovascular diseases, thus making it one of the most important risk factors in the high mortality of cardiovascular diseases. As endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are the main cell biological basis of these pathology changes of the vasculature, the structure and function of ECs and VSMCs play a key role in vascular aging. MicroRNAs (miRNAs), small noncoding RNAs, have been shown to regulate the expression of multiple messenger RNAs (mRNAs) posttranscriptionally, contributing to many crucial aspects of cell biology. Recently, miRNAs with functions associated with aging or aging-related diseases have been studied. In this review, we will summarize the reported role of miRNAs in the process of vascular aging with special emphasis on EC and VSMC functions. In addition, the potential application of miRNAs to clinical practice for the diagnosis and treatment of cardiovascular diseases will also be discussed.

MicroRNAs as regulators of endothelial cell functions in cardiometabolic diseases

Endothelial cells (ECs) provide nutrients and oxygen essential for tissue homeostasis. Metabolic imbalances and other environmental stimuli, like cytokines or low shear stress, trigger endothelial inflammation, increase permeability, compromise vascular tone, promote cell proliferation, and ultimately cause cell death. These factors contribute to EC dysfunction, which is crucial in the development of cardiometabolic diseases. microRNAs (miRNAs) are small non-coding RNAs that have important functions in the regulation of ECs. In the present review, we discuss the role of miRNAs in various aspects of EC pathology in cardiometabolic diseases like atherosclerosis, type 2 diabetes, obesity, and the metabolic syndrome, and in complication of those pathologies, like ischemia. We also discuss the potential therapeutic applications of miRNAs in promoting angiogenesis and neovascularization in tissues where the endothelium is damaged in different cardiometabolic diseases. This article is part of a Special Issue entitled: MicroRNAs and lipid/energy metabolism and related diseases edited by Carlos Fernández-Hernando and Yajaira Suárez.

MicroRNA Regulation of Atherosclerosis

Atherosclerosis and its attendant clinical complications, such as myocardial infarction, stroke, and peripheral artery disease, are the leading cause of morbidity and mortality in Western societies. In response to biochemical and biomechanical stimuli, atherosclerotic lesion formation occurs from the participation of a range of cell types, inflammatory mediators, and shear stress. Over the past decade, microRNAs (miRNAs) have emerged as evolutionarily conserved, noncoding small RNAs that serve as important regulators and fine-tuners of a range of pathophysiological cellular effects and molecular signaling pathways involved in atherosclerosis. Accumulating studies reveal the importance of miRNAs in regulating key signaling and lipid homeostasis pathways that alter the balance of atherosclerotic plaque progression and regression. In this review, we highlight current paradigms of miRNA-mediated effects in atherosclerosis progression and regression. We provide an update on the potential use of miRNAs diagnostically for detecting increasing severity of coronary disease and clinical events. Finally, we provide a perspective on therapeutic opportunities and challenges for miRNA delivery in the field.