MicroRNA-15b/16 Attenuates Vascular Neointima Formation by Promoting the Contractile Phenotype of Vascular Smooth Muscle Through Targeting YAP

MicroRNA-15b promotes cardiac ischemia injury by the inhibition of Mitofusin 2/PERK pathway

MicroRNA and mitofusin-2 (Mfn2) play an important role in the myocardial apoptosis induced by acute myocardial infarction (AMI). However, the target relationship and underlying mechanism associated with interorganelle interaction between endoplasmic reticulum (ER) and mitochondria under ischemic condition is not completely clear. MI-induced injury, Mfn2 expression, Mfn2-mediated mitochondrial function and ER stress, and target regulation by miRNA-15b (miR-15b) were evaluated by animal MI and cellular hypoxic models with advanced molecular techniques. The results confirmed that Mfn2 was down-regulated and miR-15b was up-regulated upon the target binding profile under ischemic/hypoxic condition. Our data showed that miR-15b caused cardiac apoptotic injury that was reversed by rAAV9-anti-miR-15b or AMO-15b. The damage effect of miR-15b on Mfn2 expression and mitochondrial function was observed and rescued by rAAV9-anti-miR-15b or AMO-15b. The targeted regulation of miR-15b on Mfn2 was verified by luciferase reporter and microRNA-masking. Importantly, miR-15b-mediated Mfn2 suppression activated PERK/CHOP pathway, by which leads to ER stress and mitochondrial dysfunction, and cardiac apoptosis eventually. In conclusion, our research, for the first time, revealed the missing molecular link in Mfn2 and apoptosis and elucidated that pro-apoptotic miR-15b plays crucial roles during the pathogenesis of AMI through down-regulation of Mfn2 and activation of PERK-mediated ER stress. These findings may provide an opportunity to develop new therapies for prophylaxis and treatment of ischemic heart disease.

PCSK9 expression in fibrous cap possesses a marker for rupture in advanced plaque

BACKGROUND

To date, PCSK9 inhibitors are well known for eliminating cardiac and cerebral artery ischemia events by lowering the serum lipid level. However, the pathophysiological value of in-plaque PCSK9 expression is still unclear.

METHODS

Advanced plaques removed by carotid endarterectomy were sectioned and stained to identify the PCSK9 expression pattern and its co-expression with rupture-relevant markers. To investigate the correlation of PCSK9 expression with regional blood shear flow, hemodynamic characteristics were analyzed using computational fluid dynamics, and representative parameters were compared between PCSK9 positive and negative staining plaques. To explore this phenomenon in vitro, human aortic vascular smooth muscle cells were used to overexpress and knock down PCSK9. The impacts of PCSK9 modulations on mechanical sensor activity were testified by western blot and immunofluorescence. Real-time polymerase chain reaction was used to evaluate the transcription levels of downstream rupture-prone effectors.

RESULTS

PCSK9 distribution in plaque preferred cap and shoulder regions, residing predominantly in smooth muscle actin-positive cells. Cap PCSK9 expression correlated with fibrous cap thickness negatively and co-expressed with MMP-9, both pointing to the direction of plaque rupture. A hemodynamic profile indicated a rupture-prone feature of cap PCSK9 expression. In vitro, overexpression and knockdown of PCSK9 in human aortic vascular smooth muscle cells has positive modulation on mechanical sensor Yes-associated protein 1 (YAP) activity and transcription levels of its downstream rupture-prone effectors. Serial section staining verified in situ colocalization among PCSK9, YAP, and downstream effectors.

CONCLUSIONS

Cap PCSK9 possesses a biomarker for rupture risk, and its modulation may lead to a novel biomechanical angle for plaque interventions.

Non-coding RNAs to treat vascular smooth muscle cell dysfunction

Vascular smooth muscle cell (vSMC) dysfunction is a critical contributor to cardiovascular diseases, including atherosclerosis, restenosis and vein graft failure. Recent advances have unveiled a fascinating range of non-coding RNAs (ncRNAs) that play a pivotal role in regulating vSMC function. This review aims to provide an in-depth analysis of the mechanisms underlying vSMC dysfunction and the therapeutic potential of various ncRNAs in mitigating this dysfunction, either preventing or reversing it. We explore the intricate interplay of microRNAs, long-non-coding RNAs and circular RNAs, shedding light on their roles in regulating key signalling pathways associated with vSMC dysfunction. We also discuss the prospects and challenges associated with developing ncRNA-based therapies for this prevalent type of cardiovascular pathology.

SMYD2 regulates vascular smooth muscle cell phenotypic switching and intimal hyperplasia via interaction with myocardin

The SET and MYND domain-containing protein 2 (SMYD2) is a histone lysine methyltransferase that has been reported to regulate carcinogenesis and inflammation. However, its role in vascular smooth muscle cell (VSMC) homeostasis and vascular diseases has not been determined. Here, we investigated the role of SMYD2 in VSMC phenotypic modulation and vascular intimal hyperplasia and elucidated the underlying mechanism. We observed that SMYD2 expression was downregulated in injured carotid arteries in mice and phenotypically modulated VSMCs in vitro. Using an SMC-specific SMYD2 knockout mouse model, we found that SMYD2 ablation in VSMCs exacerbated neointima formation after vascular injury in vivo. Conversely, SMYD2 overexpression inhibited VSMC proliferation and migration in vitro and attenuated arterial narrowing in injured vessels in mice. SMYD2 downregulation promoted VSMC phenotypic switching accompanied with enhanced proliferation and migration. Mechanistically, genome-wide transcriptome analysis and loss/gain-of-function studies revealed that SMYD2 up-regulated VSMC contractile gene expression and suppressed VSMC proliferation and migration, in part, by promoting expression and transactivation of the master transcription cofactor myocardin. In addition, myocardin directly interacted with SMYD2, thereby facilitating SMYD2 recruitment to the CArG regions of SMC contractile gene promoters and leading to an open chromatin status around SMC contractile gene promoters via SMYD2-mediated H3K4 methylation. Hence, we conclude that SMYD2 is a novel regulator of VSMC contractile phenotype and intimal hyperplasia via a myocardin-dependent epigenetic regulatory mechanism.

MicroRNA regulation of phenotypic transformations in vascular smooth muscle: relevance to vascular remodeling

Alterations in the vascular smooth muscle cells (VSMC) phenotype play a critical role in the pathogenesis of several cardiovascular diseases, including hypertension, atherosclerosis, and restenosis after angioplasty. MicroRNAs (miRNAs) are a class of endogenous noncoding RNAs (approximately 19-25 nucleotides in length) that function as regulators in various physiological and pathophysiological events. Recent studies have suggested that aberrant miRNAs' expression might underlie VSMC phenotypic transformation, appearing to regulate the phenotypic transformations of VSMCs by targeting specific genes that either participate in the maintenance of the contractile phenotype or contribute to the transformation to alternate phenotypes, and affecting atherosclerosis, hypertension, and coronary artery disease by altering VSMC proliferation, migration, differentiation, inflammation, calcification, oxidative stress, and apoptosis, suggesting an important regulatory role in vascular remodeling for maintaining vascular homeostasis. This review outlines recent progress in the discovery of miRNAs and elucidation of their mechanisms of action and functions in VSMC phenotypic regulation. Importantly, as the literature supports roles for miRNAs in modulating vascular remodeling and for maintaining vascular homeostasis, this area of research will likely provide new insights into clinical diagnosis and prognosis and ultimately facilitate the identification of novel therapeutic targets.

Sema3G activates YAP and promotes VSMCs proliferation and migration via Nrp2/PlexinA1

BACKGROUND

Diabetes exacerbates neointima formation after vascular procedures, manifested by accelerated proliferation and migration of vascular smooth muscle cells (VSMCs). Semaphorin 3G (Sema3G), secreted mainly from endothelial cells (ECs), regulates various cellular functions and vascular pathologies. However, the function and potential mechanism of ECs-derived Sema3G in VSMCs under diabetic condition remain unclear.

OBJECTIVE

To investigate the role and the mechanism of ECs-derived Sema3G in the regulation of VSMCs proliferation and migration.

RESULTS

ECs-derived Sema3G promoted human aortic SMCs (HASMCs) cell cycle progression and proliferation. Sema3G upregulated the expression of MMP2 and MMP9, which might explain the increased HASMCs migration by Sema3G. Inhibition of Nrp2/PlexinA1 mitigated the effect of Sema3G on promoting HASMCs proliferation and migration. Mechanistically, Sema3G inhibited LATS1 and activated YAP via Nrp2/PlexinA1. Verteporfin, an FDA-approved YAP pathway inhibitor, counteracted Sema3G-induced cyclin E and cyclin D1 expression. Besides, Sema3G expression was upregulated in ECs of diabetic mouse aortas. Serum Sema3G level was increased in type 2 diabetic patients and mice. Moreover, compared to chow diet-fed mice, high-fat diet (HFD)-fed obese mice showed thicker neointima and higher Sema3G expression in vasculature after femoral injury.

CONCLUSIONS

Our results indicated that ECs-derived Sema3G under diabetic condition activated YAP and promoted HASMCs proliferation and migration via Nrp2/PlexinA1. Thus, inhibition of Sema3G may hold therapeutic potential against diabetes-associated intimal hyperplasia.

SMYD2 Regulates Vascular Smooth Muscle Cell Phenotypic Switching and Intimal Hyperplasia via Interaction with Myocardin

The SET and MYND domain-containing protein 2 (SMYD2) is a histone lysine methyltransferase that has been reported to regulate carcinogenesis and inflammation. However, its role in vascular smooth muscle cell (VSMC) homeostasis and vascular diseases has not been determined. Here, we investigated the role of SMYD2 in VSMC phenotypic modulation and vascular intimal hyperplasia and elucidated the underlying mechanism. We observed that SMYD2 expression was downregulated in injured carotid arteries in mice and phenotypically modulated VSMCs in vitro. Using a SMC-specific Smyd2 knockout mouse model, we found that Smyd2 ablation in VSMCs exacerbates neointima formation after vascular injury in vivo. Conversely, Smyd2 overexpression inhibits VSMC proliferation and migration in vitro and attenuates arterial narrowing in injured vessels in mice. Smyd2 downregulation promotes VSMC phenotypic switching accompanied with enhanced proliferation and migration. Mechanistically, genome-wide transcriptome analysis and loss/gain-of-function studies revealed that SMYD2 up-regulates VSMC contractile gene expression and suppresses VSMC proliferation and migration, in part, by promoting expression and transactivation of the master transcription cofactor myocardin. In addition, myocardin directly interacts with SMYD2, thereby facilitating SMYD2 recruitment to the CArG regions of SMC contractile gene promoters and leading to an open chromatin status around SMC contractile gene promoters via SMYD2-mediated H3K4 methylation. Hence, we conclude that SMYD2 is a novel regulator of VSMC contractile phenotype and intimal hyperplasia via a myocardin-dependent epigenetic regulatory mechanism and may be a potential therapeutic target for occlusive vascular diseases.

miR579-3p is an inhibitory modulator of neointimal hyperplasia and transcription factors c-MYB and KLF4

Neointimal hyperplasia (IH) is a common vascular pathology that typically manifests in in-stent restenosis and bypass vein graft failure. Smooth muscle cell (SMC) phenotypic switching is central to IH, both regulated by some microRNAs, yet the role of miR579-3p, a scarcely studied microRNA, is not known. Unbiased bioinformatic analysis suggested that miR579-3p was repressed in human primary SMCs treated with different pro-IH cytokines. Moreover, miR579-3p was software-predicted to target both c-MYB and KLF4 - two master transcription factors known to promote SMC phenotypic switching. Interestingly, treating injured rat carotid arteries via local infusion of miR579-3p-expressing lentivirus reduced IH 14 days after injury. In cultured human SMCs, transfection with miR579-3p inhibited SMC phenotypic switching, as indicated by decreased proliferation/migration and increased SMC contractile proteins. miR579-3p transfection downregulated c-MYB and KLF4, and luciferase assays indicated miR579-3p's targeting of the 3'UTRs of the c-MYB and KLF4 mRNAs. In vivo, immunohistochemistry showed that treatment of injured rat arteries with the miR579-3p lentivirus reduced c-MYB and KLF4 and increased SMC contractile proteins. Thus, this study identifies miR579-3p as a previously unrecognized small-RNA inhibitor of IH and SMC phenotypic switch involving its targeting of c-MYB and KLF4. Further studies on miR579-3p may provide an opportunity for translation to develop IH-mitigating new therapeutics.

The role of miRNAs in the diagnosis of stable atherosclerosis of different arterial territories: A critical review

Atherosclerotic disease is a major cause of morbidity and mortality worldwide. Atherosclerosis may be present in different arterial territories and as a single- or multi-territorial disease. The different phenotypes of atherosclerosis are attributable only in part to acquired cardiovascular risk factors and genetic Mendelian inheritance. miRNAs, which regulate the gene expression at the post-transcriptional level, may also contribute to such heterogeneity. Numerous miRNAs participate in the pathophysiology of atherosclerosis by modulating endothelial function, smooth vascular cell function, vascular inflammation, and cholesterol homeostasis in the vessel, among other biological processes. Moreover, miRNAs are present in peripheral blood with high stability and have the potential to be used as non-invasive biomarkers for the diagnosis of atherosclerosis. However, the circulating miRNA profile may vary according to the involved arterial territory, considering that atherosclerosis expression, including the associated molecular phenotype, varies according to the affected arterial territory. In this review, we discuss the specific circulating miRNA profiles associated with atherosclerosis of different arterial territories, the common circulating miRNA profile of stable atherosclerosis irrespective of the involved arterial territory, and the circulating miRNA signature of multi-territorial atherosclerosis. miRNAs may consist of a simple non-invasive method for discriminating atherosclerosis of different arterial sites. The limitations of miRNA profiling for such clinical application are also discussed.

The Etiology and Molecular Mechanism Underlying Smooth Muscle Phenotype Switching in Intimal Hyperplasia of Vein Graft and the Regulatory Role of microRNAs

Mounting evidence suggests that the phenotypic transformation of venous smooth muscle cells (SMCs) from differentiated (contractile) to dedifferentiated (proliferative and migratory) phenotypes causes excessive proliferation and further migration to the intima leading to intimal hyperplasia, which represents one of the key pathophysiological mechanisms of vein graft restenosis. In recent years, numerous miRNAs have been identified as specific phenotypic regulators of vascular SMCs (VSMCs), which play a vital role in intimal hyperplasia in vein grafts. The review sought to provide a comprehensive overview of the etiology of intimal hyperplasia, factors affecting the phenotypic transformation of VSMCs in vein graft, and molecular mechanisms of miRNAs involved in SMCs phenotypic modulation in intimal hyperplasia of vein graft reported in recent years.

Pathophysiology of Atherosclerosis

Atherosclerosis is the main risk factor for cardiovascular disease (CVD), which is the leading cause of mortality worldwide. Atherosclerosis is initiated by endothelium activation and, followed by a cascade of events (accumulation of lipids, fibrous elements, and calcification), triggers the vessel narrowing and activation of inflammatory pathways. The resultant atheroma plaque, along with these processes, results in cardiovascular complications. This review focuses on the different stages of atherosclerosis development, ranging from endothelial dysfunction to plaque rupture. In addition, the post-transcriptional regulation and modulation of atheroma plaque by microRNAs and lncRNAs, the role of microbiota, and the importance of sex as a crucial risk factor in atherosclerosis are covered here in order to provide a global view of the disease.

CARMN Is an Evolutionarily Conserved Smooth Muscle Cell-Specific LncRNA That Maintains Contractile Phenotype by Binding Myocardin

BACKGROUND

Vascular homeostasis is maintained by the differentiated phenotype of vascular smooth muscle cells (VSMCs). The landscape of protein coding genes comprising the transcriptome of differentiated VSMCs has been intensively investigated but many gaps remain including the emerging roles of noncoding genes.

METHODS

We reanalyzed large-scale, publicly available bulk and single-cell RNA sequencing datasets from multiple tissues and cell types to identify VSMC-enriched long noncoding RNAs. The in vivo expression pattern of a novel smooth muscle cell (SMC)-expressed long noncoding RNA, Carmn (cardiac mesoderm enhancer-associated noncoding RNA), was investigated using a novel Carmn green fluorescent protein knock-in reporter mouse model. Bioinformatics and quantitative real-time polymerase chain reaction analysis were used to assess CARMN expression changes during VSMC phenotypic modulation in human and murine vascular disease models. In vitro, functional assays were performed by knocking down CARMN with antisense oligonucleotides and overexpressing Carmn by adenovirus in human coronary artery SMCs. Carotid artery injury was performed in SMC-specific Carmn knockout mice to assess neointima formation and the therapeutic potential of reversing CARMN loss was tested in a rat carotid artery balloon injury model. The molecular mechanisms underlying CARMN function were investigated using RNA pull-down, RNA immunoprecipitation, and luciferase reporter assays.

RESULTS

We identified CARMN, which was initially annotated as the host gene of the MIR143/145 cluster and recently reported to play a role in cardiac differentiation, as a highly abundant and conserved, SMC-specific long noncoding RNA. Analysis of the Carmn GFP knock-in mouse model confirmed that Carmn is transiently expressed in embryonic cardiomyocytes and thereafter becomes restricted to SMCs. We also found that Carmn is transcribed independently of Mir143/145. CARMN expression is dramatically decreased by vascular disease in humans and murine models and regulates the contractile phenotype of VSMCs in vitro. In vivo, SMC-specific deletion of Carmn significantly exacerbated, whereas overexpression of Carmn markedly attenuated, injury-induced neointima formation in mouse and rat, respectively. Mechanistically, we found that Carmn physically binds to the key transcriptional cofactor myocardin, facilitating its activity and thereby maintaining the contractile phenotype of VSMCs.

CONCLUSIONS

CARMN is an evolutionarily conserved SMC-specific long noncoding RNA with a previously unappreciated role in maintaining the contractile phenotype of VSMCs and is the first noncoding RNA discovered to interact with myocardin.

Targeting smooth muscle cell phenotypic switching in vascular disease

Objective

The phenotypic plasticity of vascular smooth muscle cells (VSMCs) is central to vessel growth and remodeling, but also contributes to cardiovascular pathologies. New technologies including fate mapping, single cell transcriptomics, and genetic and pharmacologic inhibitors have provided fundamental new insights into the biology of VSMC. The goal of this review is to summarize the mechanisms underlying VSMC phenotypic modulation and how these might be targeted for therapeutic benefit.

Methods

We summarize findings from extensive literature searches to highlight recent discoveries in the mechanisms underlying VSMC phenotypic switching with particular relevance to intimal hyperplasia. PubMed was searched for publications between January 2001 and December 2020. Search terms included VSMCs, restenosis, intimal hyperplasia, phenotypic switching or modulation, and drug-eluting stents. We sought to highlight druggable pathways as well as recent landmark studies in phenotypic modulation.

Results

Lineage tracing methods have determined that a small number of mature VSMCs dedifferentiate to give rise to oligoclonal lesions in intimal hyperplasia and atherosclerosis. In atherosclerosis and aneurysm, single cell transcriptomics reveal a striking diversity of phenotypes that can arise from these VSMCs. Mechanistic studies continue to identify new pathways that influence VSMC phenotypic plasticity. We review the mechanisms by which the current drug-eluting stent agents prevent restenosis and note remaining challenges in peripheral and diabetic revascularization for which new approaches would be beneficial. We summarize findings on new epigenetic (DNA methylation/TET methylcytosine dioxygenase 2, histone deacetylation, bromodomain proteins), transcriptional (Hippo/Yes-associated protein, peroxisome proliferator-activity receptor-gamma, Notch), and β3-integrin-mediated mechanisms that influence VSMC phenotypic modulation. Pharmacologic and genetic targeting of these pathways with agents including ascorbic acid, histone deacetylase or bromodomain inhibitors, thiazolidinediones, and integrin inhibitors suggests potential therapeutic value in the setting of intimal hyperplasia.

Conclusions

Understanding the molecular mechanisms that underlie the remarkable plasticity of VSMCs may lead to novel approaches to treat and prevent cardiovascular disease and restenosis.

A microRNA‑17‑5p/homeobox B13 axis participates in the phenotypic modulation of vascular smooth muscle cells

Vascular smooth muscle cells (VSMCs) serve a decisive role in intimal hyperplasia, a common pathophysiological process that leads to numerous vascular disorders. The present study aimed to investigate the unknown mechanisms underlying VSMC phenotypic modulation and identified a novel microRNA (miRNA/miR)‑17‑5p/homeobox B13 (HOXB13) axis involved in the phenotypic switching, proliferation and migration of VSMCs. VSMCs were isolated from the thoracic aorta of Sprague‑Dawley rats, cell proliferation was determined by Cell Counting Kit‑8 (CCK‑8) assay, cell migration was examined by Transwell migration assay and gene expression was detected using reverse transcription‑quantitative PCR and western blot analyses. It was firstly found that incubation with platelet‑derived growth factor‑BB (PDGF‑BB) recombinant protein resulted in a significant increase in HOXB13 expression in VSMCs. Using multiple miRNA prediction tools, miR‑17‑5p was identified as a potential regulator for HOXB13, since it had a 7‑base perfect binding site and a 5‑base imperfect binding site with the 3'‑untranslated region of HOXB13 mRNA, and these sequences were highly conserved across species. The regulatory effect of miR‑17‑5p on HOXB13 was validated using luciferase reporter assays. The expression level of miR‑17‑5p was increased in VSMCs under PDGF‑BB stimulation, and was negatively correlated with HOXB13 mRNA and protein expression. Moreover, the miR‑17‑5p mimics significantly inhibited the proliferation and migration of VSMCs, while antagomiR‑17‑5p showed the opposite effects, which could be abolished by HOXB13 knockdown. The miR‑17‑5p/HOXB13 axis also regulated the expression levels of the markers of differentiated VSMCs (α‑smooth muscle actin, transgelin and smoothelin), proliferating cell nuclear antigen and cell migration proteins, including MMP‑2 and ‑9. In conclusion, the present study demonstrated that miR‑17‑5p inhibited the phenotypic modulation VSMCs stimulated by PDGF‑BB by downregulating HOXB13, indicating that these factors may be potential therapeutic targets for intimal hyperplasia.

Immunomodulation of IL-33 and IL-37 with Vitamin D in the Neointima of Coronary Artery: A Comparative Study between Balloon Angioplasty and Stent in Hyperlipidemic Microswine

Inflammation is a major contributor to the development and progression of atherosclerosis. Interleukin (IL)-33 and IL-37, members of the IL-1 family, modulate inflammation, with IL-33 having a pro-inflammatory effect and IL-37 having anti-inflammatory properties. IL-37 is constitutively expressed at low levels but upregulated in inflammatory contexts. The aim of this study was to evaluate the effect of vitamin D on the expression of IL-33, IL-37, macrophages, and caspase-1 in the neointimal tissue of coronary artery in Yucatan microswine with vitamin D deficient, sufficient, and supplemented status. The intimal injury was induced by balloon angioplasty and stenting in the coronary artery, and tissues were harvested after 6 months. The expression of various proteins of interest was evaluated by immunostaining. Increased expression of IL-33 and IL-37 in the neointimal tissue of the vitamin D deficient, as compared to the sufficient and supplemented microswine, as revealed by histological evaluation and semi-quantitative analysis, suggested the immunomodulatory effect of vitamin D on the expression of IL-33 and IL-37. The minimal expression or absence of IL-33 and IL-37 expression in stented arteries is suggestive of an attenuated inflammatory response in stented arteries, compared to balloon angioplasty. The decreased IL-33 expression in the sufficient and supplemented microswine could be a potential mechanism for controlling the inflammatory process and neointima formation leading to attenuated luminal narrowing of the coronary artery. Overall, these results support supplementation of vitamin D to attenuate inflammation, neointima formation, and restenosis.

YAP1/TEAD1 upregulate platelet-derived growth factor receptor beta to promote vascular smooth muscle cell proliferation and neointima formation

We have previously demonstrated that the transcription co-factor yes-associated protein 1 (YAP1) promotes vascular smooth muscle cell (VSMC) de-differentiation. Yet, the role and underlying mechanisms of YAP1 in neointima formation in vivo remain unclear. The goal of this study was to investigate the role of VSMC-expressed YAP1 in vascular injury-induced VSMC proliferation and delineate the mechanisms underlying its action. Experiments employing gain- or loss-of-function of YAP1 demonstrated that YAP1 promotes human VSMC proliferation. Mechanistically, we identified platelet-derived growth factor receptor beta (PDGFRB) as a novel YAP1 target gene that confers the YAP1-dependent hyper-proliferative effects in VSMCs. Furthermore, we identified TEA domain transcription factor 1 (TEAD1) as a key transcription factor that mediates YAP1-dependent PDGFRβ expression. ChIP assays demonstrated that TEAD1 is enriched at a PDGFRB gene enhancer. Luciferase reporter assays further demonstrated that YAP1 and TEAD1 co-operatively activate the PDGFRB enhancer. Consistent with these observations, we found that YAP1 expression is upregulated after arterial injury and correlates with PDGFRβ expression and VSMC proliferation in vivo. Using a novel inducible SM-specific Yap1 knockout mouse model, we found that the specific deletion of Yap1 in adult VSMCs is sufficient to attenuate arterial injury-induced neointima formation, largely due to inhibited PDGFRβ expression and VSMC proliferation. Our study unravels a novel mechanism by which YAP1/TEAD1 promote VSMC proliferation via transcriptional induction of PDGFRβ, thereby enhancing PDGF-BB downstream signaling and promoting neointima formation.

Circulating level of microRNA-142-5p is a potential biomarker for predicting in-stent restenosis: a case-control study

Background

Patients who receive percutaneous coronary intervention (PCI) have different chances of developing in-stent restenosis (ISR). To date, no predictable biomarker can be applied in the clinic. MicroRNAs (miRNAs or miRs) play critical roles in transcription regulation, and their circulating levels were reported to have potential as clinical biomarkers.

Methods

In total, 93 coronary stent-implanted patients without pregnancy, liver or renal dysfunction, malignancy, hemophilia, or autoimmune diseases were recruited in this clinical study. All recruited participants were divided into an ISR group (n = 45) and a non-ISR group (n = 48) based on their restenotic status as confirmed by cardiologists at the first follow-up visit (6 months after surgery). Blood samples of all participants were harvested to measure circulating levels of miRNA candidates (miR-132, miR-142-5p, miR-15b, miR-24-2, and miR-424) to evaluate whether these circulating miRNAs can be applied as predictive biomarkers of ISR.

Results

Our data indicated that circulating levels of miR-142-5p were significantly higher in the ISR population, and results from the receiver operating characteristic (ROC) curve analysis also demonstrated superior discriminatory ability of miR-142-5p in predicting patients’ restenotic status. In addition, circulating levels of miR-15b, miR-24-2, and miR-424 had differential expressions in participants with diabetes, hyperlipidemia, and hypertension, respectively.

Conclusions

The current study revealed that the circulating level of miR-142-5p has potential application as a clinical biomarker for predicting the development of ISR in stent-implanted patients.

A novel mechanism of inhibiting in-stent restenosis with arsenic trioxide drug-eluting stent: Enhancing contractile phenotype of vascular smooth muscle cells via YAP pathway

OBJECTIVE

Arsenic trioxide (ATO or As2O3) has beneficial effects on suppressing neointimal hyperplasia and restenosis, but the mechanism is still unclear. The goal of this study is to further understand the mechanism of ATO's inhibitory effect on vascular smooth muscle cells (VSMCs).

METHODS AND RESULTS

Through in vitro cell culture and in vivo stent implanting into the carotid arteries of rabbit, a synthetic-to-contractile phenotypic transition was induced and the proliferation of VSMCs was inhibited by ATO. F-actin filaments were clustered and the elasticity modulus was increased within the phenotypic modulation of VSMCs induced by ATO in vitro. Meanwhile, Yes-associated protein (YAP) nuclear translocation was inhibited by ATO both in vivo and in vitro. It was found that ROCK inhibitor or YAP inactivator could partially mask the phenotype modulation of ATO on VSMCs.

CONCLUSIONS

The interaction of YAP with the ROCK pathway through ATO seems to mediate the contractile phenotype of VSMCs. This provides an indication of the clinical therapeutic mechanism for the beneficial bioactive effect of ATO-drug eluting stent (AES) on in-stent restenosis (ISR).

MiR-17 Knockdown Promotes Vascular Smooth Muscle Cell Phenotypic Modulation Through Upregulated Interferon Regulator Factor 9 Expression

BACKGROUND

MiR-17 is a small noncoding RNA that plays an important role in the development of tumorgenesis, which recently has emerged to be involved in regulation of inflammatory responses and angiogenesis. However, the effect and underlying mechanism of miR-17 on vascular smooth muscle cell (VSMC) phenotypic modulation have not been investigated.

METHODS AND RESULTS

In the current study, we observed that miR-17 expression tested by real-time polymerase chain reaction (RT-PCR) was downregulated in VSMCs administrated with platelet-derived growth factor-BB stimulation and carotid arteries subjected to wire injury, which were accompanied with decreased VSMC differentiation markers. Loss-of-function strategy demonstrated that miR-17 knockdown promoted VSMC phenotypic modulation characterized as decreased VSMC differentiation marker genes, increased proliferated and migrated capability of VSMC examined by RT-PCR and western blot analysis. Mechanistically, the bioinformatics analysis and luciferase assay demonstrated that miR-17 directly targeted Interferon Regulator Factor 9 (IRF9) and the upregulated IRF9 expression was responsible for the promoted effect miR-17 knockdown on VSMC phenotypic modulation.

CONCLUSIONS

Taken together, our results demonstrated that miR-17 knockdown accelerated VSMC phenotypic modulation partially through directly targeting to IRF9, which suggested that miR-17 may act as a novel therapeutic target for intimal hyperplasia management.

CircSFMBT2 facilitates vascular smooth muscle cell proliferation by targeting miR-331-3p/HDAC5

OBJECTIVE

To investigate the functional role of circSFMBT2 in vascular smooth muscle cell (VSMC) proliferation and migration and the underlying molecular mechanism.

METHODS

The circSFMBT2 levels in neointimal tissue and platelet derived growth factor-BB (PDGF-BB)-treated VSMCs were detected by qRT-PCR. The role of circSFMBT2 in VSMC proliferation, migration and cell cycle distribution was assessed by MTT assay, transwell assay, wound healing assay and flow cytometry. The protein expression of contractile markers was evaluated by western blot. In vitro luciferase reporter assay, RNA pull-down assay, ChIP and coimmunoprecipitation (CoIP) were performed to explore the effects of circSFMBT2 on the downstream signaling pathway.

RESULTS

We found that circSFMBT2 was markedly increased in neointimal tissue relative to normal tissue and PDGF-BB-treated VSMCs relative to control VSMCs. The knockdown of circSFMBT2 by siRNA significantly inhibited the proliferation and migration of VSMCs. Interestingly, circSFMBT2 knockdown enhanced the expression of contractile marker proteins including SM22α, SM myosin heavy chain (SMMHC) and calponin. Further data demonstrated that circSFMBT2 interacted with miR-331-3p as a competing endogenous RNA and up-regulated the expression of histone deacetylase 5 (HDAC5), thereby regulating the level of angiogenic factor with G patch and FHA domains (Aggf1).

CONCLUSION

These results revealed that circSFMBT2 plays a vital role in VSMC proliferation and migration through the miR-331/HDAC5/Aggf1 axis, and suggest a novel target for treating proliferative vascular diseases.

Upregulation of Orai1 and increased calcium entry contribute to angiotensin II-induced human coronary smooth muscle cell proliferation: Running Title: Angiotensin II-induced human coronary smooth muscle cells proliferation

Angiotensin II (Ang II) is an oligopeptide of the renin-angiotensin system, and Ang II-induced vascular smooth muscle cell (VSMC) proliferation is an important pathophysiological process involved in atherosclerosis; however, the underlying mechanism remains unclear. Orai1 and Stim1 are the main components of store-operated Ca²⁺ entry (SOCE), which has an important effect on VSMC proliferation. In the present study, we showed that Ang II-induced human coronary smooth muscle cell (HCSMC) proliferation was associated with increased calcium entry. The expression of Orai1, but not that of Stim1, was significantly upregulated in Ang II-treated HCSMCs. However, knockdown of Orai1 or Stim1 decreased HCSMC proliferation and SOCE activity in Ang II-treated HCSMCs. Orai1 was significantly downregulated in HCSMCs transfected with short interfering RNA (siRNA) against NOX2 or NF-κB. Transfection with siRNA against NOX2 or p65 also decreased Ang II-induced HCSMCs SOCE activation and proliferation. These findings suggested that Ang II upregulated Orai1 via the NF-κB and NOX2 pathways, leading to increased SOCE and HCSMC proliferation. The molecular factors mediating Ang II-induced SOCE upregulation are potential therapeutic targets for the prevention of Ang II-sensitive or Ang II-dependent HCSMC proliferation.

Cold-induced Yes-associated-protein expression through miR-429 mediates the browning of white adipose tissue

Targeting the white-to-brown fat conversion is important for developing potential strategies to counteract metabolic diseases; yet the mechanisms are not fully understood. Yes-associated-protein (YAP), a transcription co-activator, was demonstrated to regulate adipose tissue functions; however, its effects on browning of subcutaneous white adipose tissue (sWAT) are unclear. We demonstrated that YAP was highly expressed in cold-induced beige fat. Mechanistically, YAP was found as a target gene of miR-429, which downregulated YAP expression _{in vivo} and _{in vitro.} In addition, miR-429 level was decreased in cold-induced beige fat. Additionally, pharmacological inhibition of the interaction between YAP and transcriptional enhanced associate domains by verteporfin dampened the browning of sWAT. Although adipose tissue-specific YAP overexpression increased energy expenditure with increased basal uncoupling protein 1 expression, it had no additional effects on the browning of sWAT in young mice. However, we found age-related impairment of sWAT browning along with decreased YAP expression. Under these circumstances, YAP overexpression significantly improved the impaired WAT browning in middle-aged mice. In conclusion, YAP as a regulator of sWAT browning, was upregulated by lowering miR-429 level in cold-induced beige fat. Targeting the miR-429-YAP pathway could be exploited for therapeutic strategies for age-related impairment of sWAT browning.

Biomechanical signal communication in vascular smooth muscle cells

Biomechanical stresses are closely associated with cardiovascular development and diseases. In vivo, vascular smooth muscle cells are constantly stimulated by biomechanical factors caused by increased blood pressure leading to the non-specific activation of cell transmembrane proteins. Thus, various intracellular signal molecules are simultaneously activated via signaling cascades, which are closely related to alterations in the differentiation, phenotype, inflammation, migration, pyroptosis, calcification, proliferation, and apoptosis of vascular smooth muscle cells. Meanwhile, mechanical stress-induced miRNAs and epigenetics modification on vascular smooth muscle cells play critical roles as well. Eventually, the overall pathophysiology of the cells is altered, resulting in the development of many major clinical diseases, including hypertension, atherosclerosis, grafted venous atherosclerosis, and aneurysm, among others. In this paper, important advances in mechanical signal communication in vascular smooth muscle cells are reviewed.

The anti-inflammatory effect of miR-16 through targeting C- reactive protein is regulated by HuR in vascular smooth muscle cells

Atherosclerosis (AS) is the main pathological basis of coronary heart disease (CHD). Vascular smooth muscle cells (VMSCs) proliferation, migration and inflammatory response are the cytopathologic basis of AS. MiR-16 has been suggested to be closely associated with cell proliferation and inflammation. The regulatory role of the RNA binding protein HuR on miR-16 has been reported in colon cancer. However, the underlying roles of miR-16 on VMSCs and the regulatory function of HuR on miR-16 in VMSCs remain unknown. In this study, we found that the expression of miR-16 reduced and the expression of C-reactive protein and HuR increased when contractile VSMCs transformed into synthetic VMSCs. Furthermore, miR-16 impeded cell proliferation and inflammation via targeting CRP in VMSCs. HuR down-regulated miR-16 expression and impeded its influence on VMSCs. This study might provide an opportunity to develop a new effective target for the treatment of CHD.

Cathelicidin Modulates Vascular Smooth Muscle Cell Phenotypic Switching through ROS/IL-6 Pathway

Vascular smooth muscle cells (VSMC) are stromal cells of the blood vessels and their differentiation is thought to be essential during atherosclerosis. Cathelicidin-related antimicrobial peptides (CRAMP) are suggested to play a role in the development of atherosclerosis. Even so, the relationship of CRAMP and VSMC remains unclear. The present study was to determine whether CRAMP regulates VSMC phenotypic transformation and underlying mechanisms. We demonstrated that CRAMP could reverse platelet-derived growth factor-BB (PDGF-BB)-induced VSMC phenotypic transformation, evidencing by increasing α-smooth muscle actin (α-SMA), smooth muscle 22α (SM22α) and decreasing of proliferation and migration. Further studies showed that CRAMP inhibited nuclear factor κB (NF-κB)-induced autocrine of interleukin-6 (IL-6), which further activated of janus kinase 2 (JAK2)/signal transducer and activator 3 (STAT3). Meanwhile, our data showed that CRAMP can significantly inhibit PDGF-BB enhanced intracellular reactive oxygen species (ROS) level which further affected the NF-κB signaling pathway, indicating that CRAMP can regulate the phenotypic transformation of VSMC by regulating oxidative stress. These results indicated that CRAMP regulated the differentiation of VSMC by inhibiting ROS-mediated IL-6 autocrine, suggesting that targeting CRAMP is a potential avenue for regulating the differentiation of VSMC and treatment of atherosclerosis.

Osteoprotegerin promotes intimal hyperplasia and contributes to in-stent restenosis: Role of an αVβ3/FAK dependent YAP pathway

OBJECTIVE

Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) are related to in-stent-restenosis (ISR) following percutaneous coronary intervention (PCI). Osteoprotegerin (OPG) has been implicated in various vascular diseases. However, the effects of OPG on ISR and the underlying mechanism remained elusive. We here investigated the association between OPG and ISR, and to demonstrate the role and potential mechanisms of OPG in neointimal hyperplasia.

APPROACH AND RESULTS

From 2962 patients who received coronary angiography and follow-up coronary angiography at approximately one year, 291 patients were diagnosed with ISR, and another 291 gender- and age- matched patients without ISR were selected as controls. Serum OPG levels were significantly increased in patients with ISR. Multivariable logistic regression analysis indicated that OPG level was independently associated with the increased risk of ISR. In a mouse femoral artery wire injury model, upregulated OPG was evidenced in vascular tissue after injury. OPG deletion attenuated the vascular injury-induced neointimal hyperplasia and related gene expression in mice. OPG promoted neointimal hyperplasia and human aortic smooth muscle cell (hASMC) proliferation and migration through activation of yes-associated protein (YAP), a major downstream effector of the Hippo signaling pathway, whereas knockdown or inhibition of YAP in hASMCs blunted OPG-induced above effects. Moreover, we found that OPG, as a ligand for integrin αVβ3, mediated phosphorylation of focal adhesion kinase (FAK) and actin cytoskeleton reorganization, resulting in YAP dephosphorylation in hASMCs. OPG-dependent YAP and VSMC activation was prevented by treatment with αVβ3-blocking antibodies and inhibitors of FAK and actin stress fibers.

CONCLUSIONS

Increased serum OPG levels are associated with increased risk of ISR following PCI and OPG could promote neointimal hyperplasia in response to injury through integrin αVβ3 mediated FAK and YAP activation, indicating OPG/YAP inhibition might serve as an attractive novel target for the prevention of ISR after PCI.

Diagnostic and theranostic microRNAs in the pathogenesis of atherosclerosis

MicroRNAs (miRNAs) are a group of small single strand and noncoding RNAs that regulate several physiological and molecular signalling pathways. Alterations of miRNA expression profiles may be involved with pathophysiological processes underlying the development of atherosclerosis and cardiovascular diseases, including changes in the functions of the endothelial cells and vascular smooth muscle cells, such as cell proliferation, migration and inflammation, which are involved in angiogenesis, macrophage function and foam cell formation. Thus, miRNAs can be considered to have a crucial role in the progression, modulation and regulation of every stage of atherosclerosis. Such potential biomarkers will enable us to predict therapeutic response and prognosis of cardiovascular diseases and adopt effective preclinical and clinical treatment strategies. In the present review article, the current data regarding the role of miRNAs in atherosclerosis were summarized and the potential miRNAs as prognostic, diagnostic and theranostic biomarkers in preclinical and clinical studies were further discussed. The highlights of this review are expected to present opportunities for future research of clinical therapeutic approaches in vascular diseases resulting from atherosclerosis with an emphasis on miRNAs.

Involvement of Yes-associated protein 1 (YAP1) in doxorubicin-induced cytotoxicity in H9c2 cardiac cells

Cardiac cell death is one of the major events implicated in doxorubicin-induced cardiotoxicity, which leads to heart failure. We recently reported that Yes-associated protein 1 (YAP1) regulates cell survival and apoptosis. However, it is unclear whether YAP1 regulates doxorubicin-induced cell death in cardiomyocytes. We investigated whether YAP1 is involved in doxorubicin-induced cell death using H9c2 cardiac cells and mouse heart. In an in vivo study, YAP1 protein expression was significantly decreased in hearts of doxorubicin-treated mice with increased caspase-3 activation. Doxorubicin also caused cell death by increasing caspase-3 activation in H9c2 cells. Doxorubicin reduced YAP1 protein expression and messenger RNA expression accompanied by increased phosphorylation of YAP1 at Ser127. Doxorubicin further increased cell death with increased caspase-3/7 activation in the absence of YAP1 when compared with doxorubicin or siYAP1 treatment alone. Overexpression of constitutively active YAP1 (YAP1-5SA) using an adenovirus gene transfer technique significantly reversed doxorubicin-induced cell death by decreasing caspase-3/7 activation in H9c2 cells. Akt, a potential prosurvival factor, decreased in doxorubicin- and YAP1 short interfering RNA (siRNA)-treated cells. Doxorubicin further significantly decreased Akt protein expression when YAP1 was silenced. Overexpression of YAP1 canceled decreased Akt protein expression induced by doxorubicin treatment in H9c2 cells. In conclusion, these results suggest that doxorubicin-induced cardiac cell death is mediated in part by down-regulation of YAP1 and YAP1-targeted gene, Akt. Modulating YAP1 and its related Hippo pathway on local cardiomyocytes may be a promising therapeutic approach for doxorubicin-induced cardiotoxicity.

Drug-eluting stent specifically designed to target vascular smooth muscle cell phenotypic modulation attenuated restenosis through the YAP pathway

Vascular smooth muscle cell (SMC) phenotypic modulation contributes to the development of restenosis. A sorafenib-eluting stent was specifically designed to target SMC phenotypic modulation to inhibit in-stent restenosis in the present study. SMC contractile protein from the freshly isolated rat aorta was expressed at a high level, but its expression was dramatically reduced after SMCs were cultured in 10% FBS for 1 wk. After sorafenib treatment, SMC contractile protein expression was markedly upregulated. We further observed that Yes-associated protein (YAP) expression was attenuated after sorafenib treatment in a dose-dependent manner. Overexpression of YAP by lentivirus reversed the expression of sorafenib-induced SMC contractile protein and increased the expression of cyclin D. Mechanistically, sorafenib regulated the serum response factor-myocardin (SRF-Myocd) complex through competitive binding of YAP to Myocd and increased SRF binding to CArG-containing regions of SMC-specific contractile genes within intact chromatin, thereby controlling the activity of smooth muscle-specific gene transcription. In a rabbit carotid model, the sorafenib-eluting stent (SFES) dramatically inhibited in-stent restenosis and upregulated SMC contractile protein expression. Overexpression of YAP blocked the antirestenosis effect of SFES and repressed contractile smooth muscle-specific genes in vivo, indicating that SFES attenuated in-stent restenosis through YAP-mediated SMC phenotypic modulation. We demonstrated that SFES attenuated in-stent restenosis through YAP-mediated SMC phenotypic modulation. Targeting SMC phenotypic modulation by drug-eluting stent represents an attractive therapeutic approach for the treatment of occlusive vascular diseases.NEW & NOTEWORTHY In the present study, we demonstrated that sorafenib regulates smooth muscle cell (SMC) phenotypic modulation from a proliferative to a contractile state. Sorafenib induced a myocardin-serum response factor interaction and increased SMC contractile gene transcription through the Yes-associated protein pathway. Moreover, local delivery of sorafenib regulating SMC phenotypic modulation represents a promising strategy in the design of drug-eluting stents.

Transcription factor TEAD1 is essential for vascular development by promoting vascular smooth muscle differentiation

TEAD1 (TEA domain transcription factor 1), a transcription factor known for the functional output of Hippo signaling, is important for tumorigenesis. However, the role of TEAD1 in the development of vascular smooth muscle cell (VSMC) is unknown. To investigate cell-specific role of Tead1, we generated cardiomyocyte (CMC) and VSMC-specific Tead1 knockout mice. We found CMC/VSMC-specific deletion of Tead1 led to embryonic lethality by E14.5 in mice due to hypoplastic cardiac and vascular walls, as a result of impaired CMC and VSMC proliferation. Whole transcriptome analysis revealed that deletion of Tead1 in CMCs/VSMCs downregulated expression of muscle contractile genes and key transcription factors including Pitx2c and myocardin. In vitro studies demonstrated that PITX2c and myocardin rescued TEAD1-dependent defects in VSMC differentiation. We further identified Pitx2c as a novel transcriptional target of TEAD1, and PITX2c exhibited functional synergy with myocardin by directly interacting with myocardin, leading to augment the differentiation of VSMC. In summary, our study reveals a critical role of Tead1 in cardiovascular development in mice, but also identifies a novel regulatory mechanism, whereby Tead1 functions upstream of the genetic regulatory hierarchy for establishing smooth muscle contractile phenotype.

Rab7‑mediated autophagy regulates phenotypic transformation and behavior of smooth muscle cells via the Ras/Raf/MEK/ERK signaling pathway in human aortic dissection

Autophagy regulates the metabolism, survival and function of numerous types of cell, including cells that comprise the cardiovascular system. The dysfunction of autophagy has been demonstrated in atherosclerosis, restenotic lesions and hypertensive vessels. As a member of the Ras GTPase superfamily, Rab7 serves a significant role in the regulation of autophagy. The present study evaluated how Rab7 affects the proliferation and invasion, and phenotypic transformations of aortic dissection (AD) smooth muscle cells (SMCs) via autophagy. Rab7 was overexpressed in AD tissues and the percentage of synthetic human aortic SMCs (HASMCs) was higher in AD tissues compared with NAD tissues. Downregulation of Rab7 decreased cell growth, reduced the number of invasive cells and decreased the percentage cells in the G1 phase. Autophagy of HASMCs was inhibited following Rab7 knockdown. Inhibition of autophagy with 3‑methyladenine or Rab7 knockdown suppressed the phenotypic conversion of contractile to synthetic HASMCs. The action of Rab7 may be mediated by inhibiting the Ras/Raf/mitogen‑activated protein kinase (MAPK) kinase (MEK)/extracellular signal related kinase (ERK) signaling pathway. In conclusion, the results revealed that Rab7‑mediated autophagy regulated the behavior of SMCs and the phenotypic transformations in AD via activation of the Ras/Raf/MEK/ERK signaling pathway. The findings of the present study may improve understanding of the role Rab7 in the molecular etiology of AD and suggests the application of Rab7 as a novel therapeutic target in the treatment of human AD.

MicroRNA-365 promotes the contractile phenotype of venous smooth muscle cells and inhibits neointimal formation in rat vein grafts

The high rate of autologous vein graft failure caused by neointimal hyperplasia remains an unresolved issue in the field of cardiovascular surgery; therefore, it is important to explore new methods for protecting against neointimal hyperplasia. MicroRNA-365 has been reported to inhibit the proliferation of vascular smooth muscle cells (SMCs). This study aimed to test whether adenovirus-mediated miR-365 was able to attenuate neointimal formation in rat vein grafts. We found that miR-365 expression was substantially reduced in vein grafts following engraftment. In vitro, overexpression of miR-365 promoted smooth muscle-specific gene expression and inhibited venous SMC proliferation and migration. Consistent with this, overexpression of miR-365 in a rat vein graft model significantly reduced grafting-induced neointimal formation and effectively improved the hemodynamics of the vein grafts. Mechanistically, we identified that cyclin D1 as a potential downstream target of miR-365 in vein grafts. Specially, to increase the efficiency of miR-365 gene transfection, a 30% poloxamer F-127 gel containing 0.25% trypsin was mixed with adenovirus and spread around the vein grafts to increase the adenovirus contact time and penetration. We showed that adenovirus-mediated miR-365 attenuated venous SMC proliferation and migration in vitro and effectively inhibited neointimal formation in rat vein grafts. Restoring expression of miR-365 is a potential therapeutic approach for the treatment of vein graft failure. © 2019 IUBMB Life, 2019.

The microRNAs Regulating Vascular Smooth Muscle Cell Proliferation: A Minireview

Vascular smooth muscle cell (VSMC) proliferation plays a critical role in atherosclerosis. At the beginning of the pathologic process of atherosclerosis, irregular VSMC proliferation promotes plaque formation, but in advanced plaques VSMCs are beneficial, promoting the stability and preventing rupture of the fibrous cap. Recent studies have demonstrated that microRNAs (miRNAs) expressed in the vascular system are involved in the control of VSMC proliferation. This review summarizes recent findings on the miRNAs in the regulation of VSMC proliferation, including miRNAs that exhibit the inhibition or promotion of VSMC proliferation, and their targets mediating the regulation of VSMC proliferation. Up to now, most of the studies were performed only in cultured VSMC. While the modulation of miRNAs is emerging as a promising strategy for the regulation of VSMC proliferation, most of the effects of miRNAs and their targets in vivo require further investigation.

Platelet-endothelial cell interactions modulate smooth muscle cell phenotype in an in vitro model of type 2 diabetes mellitus

Platelet (PLT)-endothelial cell (EC) interaction appears to contribute to phenotypic transition of vascular smooth muscle cells (VSMCs), which play an important role in the physiological and pathological process of vascular complications in type 2 diabetes mellitus (DM2). However, the precise mechanisms by which interactions between PLTs and ECs affect VSMC phenotype have largely remained unclear. We determined the effect of diabetic PLT-EC interaction to influence VSMC migration, proliferation, and phenotypic transformation in triple-cell coculture models using the quantitative real-time PCR, Western blot, fluorescence microscopy, wound scratch assays, CCK-8 assays, and gelatin zymography assays. Our results revealed DM2 PLT-EC interaction to be associated with a significant downregulation of VSMC-specific contractile phenotypic genes and proteins, including SM22α, smooth muscle actin, Smoothelin-B, and smooth muscle-myosin heavy chain. Inversely, VSMC-specific proliferative phenotype gene and protein levels, including cyclin D1 and 2, nonmuscle myosin heavy chain B, and PCNA were in upregulation. Furthermore, the DM2-originated PLT-EC interaction promoted the expression level of transforming growth factor-β1, and the PI3K/Akt and matrix metalloproteinase 9 signaling pathway was activated subsequently. Finally, these reactions contributed to a synthetic phenotype of VSMCs, including the proliferation, migration, and gelatinolytic activities. These findings suggest that PLT-EC interaction modulates the phenotypic transition of VSMCs between a contractile and proliferative/synthetic phenotype under diabetic conditions, conceivably providing important implications regarding the mechanisms controlling the VSMC phenotypic transition and the development of cardiovascular complications.

Elucidating the contributory role of microRNA to cardiovascular diseases (a review)

Cardiovascular diseases encompassing atherosclerosis, aortic aneurysms, restenosis, and pulmonary arterial hypertension, remain the leading cause of morbidity and mortality worldwide. In response to a range of stimuli, the dynamic interplay between biochemical and biomechanical mechanisms affect the behaviour and function of multiple cell types, driving the development and progression of cardiovascular diseases. Accumulating evidence has highlighted microRNAs (miRs) as significant regulators and micro-managers of key cellular and molecular pathophysiological processes involved in predominant cardiovascular diseases, including cell mitosis, motility and viability, lipid metabolism, generation of inflammatory mediators, and dysregulated proteolysis. Human pathological and clinical studies have aimed to identify select microRNA which may serve as biomarkers of disease and their progression, which are discussed within this review. In addition, I provide comprehensive coverage of in vivo investigations elucidating the modulation of distinct microRNA on the pathophysiology of atherosclerosis, abdominal aortic aneurysms, restenosis, and pulmonary arterial hypertension. Collectively, clinical and animal studies have begun to unravel the complex and often diverse effects microRNAs and their targets impart during the development of cardiovascular diseases and revealed promising therapeutic strategies through which modulation of microRNA function may be applied clinically.

Non-coding RNAs in vascular remodeling and restenosis

Vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) are crucial in vascular remodeling. They exert pivotal roles in the development and progression of atherosclerosis, vascular response to injury, and restenosis after transcatheter angioplasty. As a witness of their importance in the cardiovascular system, a large body of evidence has accumulated about the role played by micro RNAs (miRNA) in modulating both VSMCs and ECs. More recently, a growing number of long noncoding RNA (lncRNAs) came beneath the spotlights in this research field. Several mechanisms have been revealed by which lncRNAs are able to exert a relevant biological impact on vascular remodeling. The aim of this review is to provide an integrated summary of ncRNAs that exert a relevant biological function in VSMCs and ECs of the vascular wall, with emphasis on the available clinical evidence of the potential usefulness of these molecules as circulating biomarkers of in-stent restenosis.

Transcoronary gradients of HDL-associated MicroRNAs in unstable coronary artery disease

AIMS

MicroRNAs (miRNAs) are transported on high-density lipoproteins (HDLs) and HDL-associated miRNAs are involved in intercellular communication. We explored HDL-associated miRNAs concentration gradients across the coronary circulation in stable and unstable coronary artery disease patients and whether changes in the transcoronary gradient were associated with changes in HDL composition and size.

METHODS

Acute coronary syndrome (ACS, n=17) patients, those with stable coronary artery disease (stable CAD, n=19) and control subjects without CAD (n=6) were studied. HDLs were isolated from plasma obtained from the coronary sinus (CS), aortic root (arterial blood) and right atrium (venous blood). HDL-associated miRNAs (miR-16, miR-20a, miR-92a, miR-126, miR-222 and miR-223) were quantified by TaqMan miRNA assays. HDL particle sizes were determined by non-denaturing polyacrylamide gradient gel electrophoresis. HDL composition was measured immunoturbidometrically or enzymatically.

RESULTS

A concentration gradient across the coronary circulation was observed for all the HDL-associated miRNAs. In ACS patients, there was a significant inverse transcoronary gradient for HDL-associated miR-16, miR-92a and miR-223 (p<0.05) compared to patients with stable CAD. Changes in HDL-miRNA transcoronary gradients were not associated with changes in HDL composition or size.

CONCLUSION

HDLs are depleted of miR-16, miR-92a and miR-223 during the transcoronary passage in patients with ACS compared to patients with stable CAD.

Long noncoding RNA NEAT1 (nuclear paraspeckle assembly transcript 1) is critical for phenotypic switching of vascular smooth muscle cells

In response to vascular injury, vascular smooth muscle cells (VSMCs) may switch from a contractile to a proliferative phenotype thereby contributing to neointima formation. Previous studies showed that the long noncoding RNA (lncRNA) NEAT1 is critical for paraspeckle formation and tumorigenesis by promoting cell proliferation and migration. However, the role of NEAT1 in VSMC phenotypic modulation is unknown. Herein we showed that NEAT1 expression was induced in VSMCs during phenotypic switching in vivo and in vitro. Silencing NEAT1 in VSMCs resulted in enhanced expression of SM-specific genes while attenuating VSMC proliferation and migration. Conversely, overexpression of NEAT1 in VSMCs had opposite effects. These in vitro findings were further supported by in vivo studies in which NEAT1 knockout mice exhibited significantly decreased neointima formation following vascular injury, due to attenuated VSMC proliferation. Mechanistic studies demonstrated that NEAT1 sequesters the key chromatin modifier WDR5 (WD Repeat Domain 5) from SM-specific gene loci, thereby initiating an epigenetic "off" state, resulting in down-regulation of SM-specific gene expression. Taken together, we demonstrated an unexpected role of the lncRNA NEAT1 in regulating phenotypic switching by repressing SM-contractile gene expression through an epigenetic regulatory mechanism. Our data suggest that NEAT1 is a therapeutic target for treating occlusive vascular diseases.

MiRNA-16 inhibited oral squamous carcinoma tumor growth in vitro and in vivo via suppressing Wnt/β-catenin signaling pathway

Background

Oral carcinoma, one of the most commonly diagnosed cancers, has a poor prognosis and low survival rate with treatment. In recent years, some studies reported the upregulation of miRNA-16 (miR-16) in the oral carcinoma, whereas some other studies confirmed the downregulation of miR-16. In the current study, we aimed to investigate the function of miR-16 in oral carcinoma.

Materials and methods

Cell proliferation assay was measured by MTT assay, quantitative real time polymerase chain reaction (qRT-PCR) was used to evaluate the expression of miR-16, and apoptosis was analyzed by flow cytometry. In addition, the expression of proteins was detected by Western blot. Moreover, xenograft tumor model was established to detect the effect of miR-16 in vivo.

Results

The results suggested that miR-16 was downregulated in the oral carcinoma tissues. Overexpression of miR-16 inhibited the growth and proliferation of oral squamous carcinoma cells (OSCCs) and induced apoptosis both in vitro and in vivo, which is due to the suppression of Wnt/β-catenin signaling pathway.

Conclusion

This study provides evidence that overexpression of miR-16 inhibits OSCC growth by regulating Wnt/β-catenin signaling. Our findings suggest that overexpression of miR-16 could be a potential approach for gene therapy of OSCC in future.

Characterization of mice carrying a conditional TEAD1 allele

The Hippo- yes-associated protein (YAP) pathway is essential for controlling organ size and tumorigenesis. Previous studies have demonstrated that the primary outcome of YAP signaling in the nucleus is achieved by interaction with the transcription factor TEA domain transcription factor (TEAD1). The YAP/TEAD1 complex binds to DNA element and regulates the expression of genes involved in cell growth. However, constitutive knockout of TEAD1 leads to early embryonic lethality in mice. Thus, generation of a floxed TEAD1 mouse becomes crucial for further understanding mid- to late-gestation and post-natal role of TEAD1. Herein, we created and characterized a mouse model that allows for conditional disruption of TEAD1. Embryonic fibroblasts derived from the floxed TEAD1 mice enabled the Cre-mediated deletion of TEAD1 in vitro using virally delivered Cre recombinase. Furthermore, crossing the floxed TEAD1 mouse with a ubiquitously expressing Cre mouse resulted in efficient ablation of the floxed allele in vivo, and the animals recapitulated early embryonic lethality defects. In conclusion, our data demonstrate an important role of TEAD1 in early development in mice, and the floxed TEAD1 mouse model will be a valuable genetic tool to determine the temporal and tissue-specific functions of TEAD1.

Mechanobiological Feedback in Pulmonary Vascular Disease

Vascular stiffening in the pulmonary arterial bed is increasingly recognized as an early disease marker and contributor to right ventricular workload in pulmonary hypertension. Changes in pulmonary artery stiffness throughout the pulmonary vascular tree lead to physiologic alterations in pressure and flow characteristics that may contribute to disease progression. These findings have led to a greater focus on the potential contributions of extracellular matrix remodeling and mechanical signaling to pulmonary hypertension pathogenesis. Several recent studies have demonstrated that the cellular response to vascular stiffness includes upregulation of signaling pathways that precipitate further vascular remodeling, a process known as mechanobiological feedback. The extracellular matrix modifiers, mechanosensors, and mechanotransducers responsible for this process have become increasingly well-recognized. In this review, we discuss the impact of vascular stiffening on pulmonary hypertension morbidity and mortality, evidence in favor of mechanobiological feedback in pulmonary hypertension pathogenesis, and the major contributors to mechanical signaling in the pulmonary vasculature.

MicroRNA‑29a contributes to intracranial aneurysm by regulating the mitochondrial apoptotic pathway

Intracranial aneurysm (IA) is an abnormal expansion in the intracranial arteries that weakens the arterial wall by consistently pushing the vascular wall outwards, which leads to a higher risk of aneurysm rupture. A number of reports have demonstrated that apoptosis is associated with the growth and rupture of IA. MicroRNAs (miRNAs/miRs) perform vital roles in the regulation of the mitochondrial apoptotic pathway and signaling proteins. Increasing evidence has already revealed the role of miR‑29a in injury, including liver injury, cardiovascular injury and ischaemia‑reperfusion injury. However, the role of miR‑29a in IA remains unclear at present. The present study investigated the role of miR‑29a in IA pathogenesis and the underlying mechanisms. By using reverse transcription‑quantitative polymerase chain reaction and western blot analysis, the present study demonstrated that genes, including caspase‑3, ‑8 and ‑9, and proteins, including cytochrome c and myeloid cell leukemia 1 (Mcl‑1), involved in mitochondrial apoptosis pathways were upregulated in IA groups compared with controls. In addition, microarray analysis demonstrated that miR‑29a, one of the most altered miRs in IA mice, was overexpressed in IA mice compared with controls. In vitro experiments revealed that miR‑29a downregulation attenuated human brain vascular smooth muscle cell (HBVSMC) apoptosis, while miR‑29a overexpression increased the apoptosis of HBVSMCs. Furthermore, luciferase reporter analysis revealed that Mcl‑1 is a direct target gene of miR‑29a. An in vivo IA model confirmed that miR‑29a overexpression may promote apoptosis through mitochondrial pathways. It was therefore concluded that miR‑29a may contribute to the progression of IA by regulating mitochondrial apoptotic pathways. Thus, miR‑29a is a potential therapeutic target for IA.

Macrophage-stimulated microRNA expression in mural cells promotes transplantation-induced neointima formation

In this study, we tested the possibility that macrophages might contribute to neointima formation by stimulating microRNA expressions in mural cells. Thoracic aortas from F344 rats were transplanted into recipient Lewis rats. Clodronate liposome was used for in vivo macrophage depletion. Using miR-21 as a prototypic example of vascular enriched microRNA, we showed that macrophage depletion reduced the expression level of miR-21, which was upregulated in the allograft. This effect of macrophage depletion was accompanied by attenuations in neointimal hyperplasia and transplantation-induced vascular inflammation. Using in vitro assays, we identified that macrophages might stimulate miR-21 expression in smooth muscle cells and adventitial fibroblasts via the release of tumor necrosis factor-α. We also showed that silencing of miR-21 suppressed tumor necrosis factor-induced proliferation, migration, and inflammatory responses in mural cells. Our results suggest that macrophage may promote transplantation-induced neointima formation by stimulating miR-21 expression in vascular mural cells, which promotes mural cell proliferation, migration and/or inflammation. Moreover, we have established that tumor necrosis factor-α has a major role in mediating this paracrine process.