Effect of microRNA-145 to prevent vein graft disease in rabbits by regulation of smooth muscle cell phenotype

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.

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.

miR-16-5p Is a Novel Mediator of Venous Smooth Muscle Phenotypic Switching

Vein graft failure after coronary artery bypass grafting (CABG) is primarily caused by intimal hyperplasia, which results from the phenotypic switching of venous smooth muscle cells (SMCs). This study investigates the role and underlying mechanism of miR-16-5p in the phenotypic switching of venous SMCs. In rats, neointimal thickness and area increased over time within 28 days after CABG, as did the time-dependent miR-16-5p downregulation and SMC phenotypic switching. Platelet-derived growth factor-BB-induced miR-16-5p downregulation in HSVSMCs was accompanied by and substantially linked with alterations in phenotypic switching indicators. Furthermore, miR-16-5p overexpression increased SMCs differentiation marker expression while suppressing HSVSMCs proliferation and migration and drastically inhibiting neointimal development in vein grafts. The miR-16-5p inhibited zyxin expression, which was necessary for HSVSMCs phenotypic switching. The miR-16-5p/zyxin axis is a novel, potentially therapeutic target for preventing and treating venous graft intimal hyperplasia.

Therapeutic MK2 inhibition blocks pathological vascular smooth muscle cell phenotype switch

Vascular procedures, such as stenting, angioplasty, and bypass grafting, often fail due to intimal hyperplasia (IH), wherein contractile vascular smooth muscle cells (VSMCs) dedifferentiate to synthetic VSMCs, which are highly proliferative, migratory, and fibrotic. Previous studies suggest MAPK-activated protein kinase 2 (MK2) inhibition may limit VSMC proliferation and IH, although the molecular mechanism underlying the observation remains unclear. We demonstrated here that MK2 inhibition blocked the molecular program of contractile to synthetic dedifferentiation and mitigated IH development. Molecular markers of the VSMC contractile phenotype were sustained over time in culture in rat primary VSMCs treated with potent, long-lasting MK2 inhibitory peptide nanopolyplexes (MK2i-NPs), a result supported in human saphenous vein specimens cultured ex vivo. RNA-Seq of MK2i-NP-treated primary human VSMCs revealed programmatic switching toward a contractile VSMC gene expression profile, increasing expression of antiinflammatory and contractile-associated genes while lowering expression of proinflammatory, promigratory, and synthetic phenotype-associated genes. Finally, these results were confirmed using an in vivo rabbit vein graft model where brief, intraoperative treatment with MK2i-NPs decreased IH and synthetic phenotype markers while preserving contractile proteins. These results support further development of MK2i-NPs as a therapy for blocking VSMC phenotype switch and IH associated with cardiovascular procedures.

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.

Diverse roles of microRNA-145 in regulating smooth muscle (dys)function in health and disease

MicroRNAs are short, non-coding RNAs that target messenger RNAs for degradation. miR-145 is a vascular-enriched microRNA that is important for smooth muscle cell (SMC) differentiation. Under healthy circumstances, SMC exist in a contractile, differentiated phenotype promoted by miR-145. In cases of disease or injury, SMC can undergo reversible dedifferentiation into a synthetic phenotype, accompanied by inhibition of miR-145 expression. Vascular disorders such as atherosclerosis and neointimal hyperplasia are characterised by aberrant phenotypic switching in SMC. This review will summarise the physiological roles of miR-145 in vascular SMC, including the molecular regulation of differentiation, proliferation and migration. Furthermore, it will discuss the different ways in which miR-145 can be dysregulated and the downstream impact this has on the progression of vascular pathologies. Finally, it will discuss whether miR-145 may be suitable for use as a biomarker of vascular disease.

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.

MicroRNA-92a -mediated endothelial to mesenchymal transition controls vein graft neointimal lesion formation

PURPOSE

Long-term failure of vein grafts due to neointimal hyperplasia remains an important problem in coronary artery bypass graft surgery. Endothelial to mesenchymal transition (EndMT) contributes to vein graft vascular remodeling. However, there is little study on microRNA-mediated EndMT contributions to neointimal formation in vein graft. We hypothesized that microRNA-92a (miR-92a) might play an important role in determining EndMT contributions to neointimal formation.

METHODS

miR-92a and EndMT-related proteins detected by qRT-PCR and Western blot in vitro and in vivo. Adeno-associated virus 6 (AAV6) delivery gene therapy was used to inhibit neointimal formation in vivo. The intimal hyperplasia of vein grafts was measured by HE staining, the expression of EndMT-related protein in vein grafts was measured by immunofluorescence. Immunohistochemistry and luciferase assay were used to detect potential targets of miR-92a.

RESULTS

The expression of miR-92a was found to be upregulated in neointimal hyperplasic lesions after vein grafting. Using cultured human umbilical vein endothelial cells (HUVECs), we show that TGF-β1 treatment of HUVECs significantly increased miR-92a expression and induced EndMT, characterized by suppression of endothelial-specific markers (CD31 and VE-cadherin) and an increase in mesenchymal-specific markers (a-SMA and vimentin), while inhibition of miR-92a expression blunted EndMT in cultured HUVECs. Furthermore, AAV6 mediated miR-92a suppression gene therapy effectively resulted in decreased EndMT and less neointimal formation in vein grafts in vivo. We further identified that integrin alpha 5 (ITGA5) is a potential target gene involved in the development of neointima formation in these vein grafts.

CONCLUSION

This data suggests that neointimal formation does not solely rely on vascular smooth muscle cell phenotypic switching but is also related to EndMT, and miR-92a-mediated EndMT is an important mechanism underlying neointimal formation in vein grafts.

miR-145 inhibits the proliferation and migration of vascular smooth muscle cells by regulating autophagy

miR-145, the most abundant miRNA in the vascular smooth muscle cells (VSMCs), regulates VSMC function in intimal hyperplasia. It has been reported that autophagy participates in the regulation of proliferation and migration of VSMCs. However, the effect of miR-145 on autophagy and related mechanism in the proliferation and migration of VSMCs remains unclear. Therefore, we aimed to determine the effect of miR-145 on autophagy and the mechanism in VSMCs. Cell autophagy was determined by transmission electron microscope, mRFP-GFP-LC3 assay and Western blotting. A recombinant lentivirus containing miR-145 was used to construct VSMCs with miR-145 overexpression. We found that miR-145 expression was decreased, and autophagy was increased in the carotid arteries of C57BL/6J mice with intimal hyperplasia and TGF-β1-stimulated VSMCs. Furthermore, miR-145 overexpression inhibited cell autophagy, whereas miR-145 inhibition promoted autophagy in TGF-β1-stimulated VSMCs. Meanwhile, miR-145 inhibited the proliferation and migration of VSMCs. More importantly, our study showed that autophagy inhibition augmented the inhibitory effect of miR-145 on the proliferation and migration of VSMCs. In addition, we found that the sirtuins are not direct targets of miR-145 in the proliferation and migration of VSMCs. These results suggest that miR-145 inhibits the proliferation and migration of VSMCs by suppressing the activation of autophagy.

Transcriptional regulation of microRNA-126a by farnesoid X receptor in vitro and in vivo

OBJECTIVES

Recent research has indicated the microRNA-126a (miR-126a) is an endothelial cell-specific and highly conserved endogenous small non-coding RNA molecule. It contributes to the vascular integrity and angiogenesis, but the molecular regulation mechanism of miR-126a remains unknown.

RESULTS

Herein, quantitative real-time polymerase chain reaction (qRT-PCR) results showed that Farnesoid X Receptor (FXR) activation promoted miR-126a expression in HepG2, LO2, and Hep1-6 cells. Furthermore, FXR was found to transcriptionally regulate the miR-126a by binding to its DR8 site. The binding site of FXR was confirmed on intron 6 or 7 of miR-126a host gene epidermal growth factor-like domain 7 (EGFL7) by luciferase reporter assays, electrophoretic mobility shift assays (EMSAs) and chromatin immunoprecipitation (ChIP) assays.

CONCLUSIONS

All these data collectively suggest that FXR regulates transcripts of miR-126a by binding to DR8 in miR-126a gene promoter. This study may provide a molecular therapeutic target for angiogenic disorders, aging, and liver failure.

Reconstruction of a lncRNA-Associated ceRNA Network in Endothelial Cells under Circumferential Stress

Background

Numerous studies have highlighted that long noncoding RNA (lncRNA) can indirectly regulate the expression of mRNAs by binding to microRNA (miRNA). LncRNA-associated ceRNA networks play a vital role in the initiation and progression of several pathological mechanisms. However, the lncRNA-miRNA-mRNA ceRNA network in endothelial cells under cyclic stretch is seldom studied.

Methods

The miRNA, mRNA, and lncRNA expression profiles of 6 human umbilical vein endothelial cells (HUVECs) under circumferential stress were obtained by next-generation sequencing (NGS). We identified the differential expression of miRNAs, mRNAs, and lncRNAs using the R software package GDCRNATools. Cytoscape was adopted to construct a lncRNA-miRNA-mRNA ceRNA network. In addition, through GO and KEGG pathway annotations, we analyzed gene functions and their related pathways. We also adopted ELISA and TUNEL to investigate the effect of si-NEAT1 on endothelial inflammation and apoptosis.

Results

We recognized a total of 32978 lncRNAs, 1046 miRNAs, and 31958 mRNAs in 6 samples; among them, 155 different expressed lncRNAs, 74 different expressed miRNAs, and 960 different mRNAs were adopted. Based on the established theory, the ceRNA network was composed of 13 lncRNAs, 44 miRNAs, and 115 mRNAs. We constructed and visualized a lncRNA-miRNA-mRNA network, and the top 20 nodes are identified after calculating their degrees. The nodes with most degrees in three kinds of RNAs are hsa-miR-4739, NEAT1, and MAP3K2. Functional analysis showed that different biological processes enriched in biological regulation, response to stimulus and cell communication. Pathway analysis was mainly enriched in longevity regulating, cell cycle, mTOR, and FoxO signaling pathway. Circumferential stress can significantly downregulate NEAT1, and after transducing si-NEAT1 for 24 h, inflammatory cytokine IL-6 and MCP-1 were significantly increased; furthermore, fewer TUNEL-positive cells were found in the si-NEAT1 treated group.

Conclusions

The establishing of a ceRNA network can help further understand the mechanism of vein graft failure. Our data demonstrated that NEAT1 may be a core factor among the mechanical stress factors and that cyclic stress can significantly reduce expression of NEAT1, give rise to inflammation in the early stage of endothelial dysfunction, and promote EC apoptosis, which may play an essential role in vein graft failure.

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.

Review of risk factors, treatment, and prevention of saphenous vein graft disease after coronary artery bypass grafting

Saphenous vein graft disease (SVGD) is a type of vascular disease that may develop after coronary artery bypass grafting (CABG). SVGD seriously affects the short-term and long-term effects of CABG and increases the incidence of major adverse cardiovascular events. It is very important to identify patients at greatest risk and carry out prevention and treatment measures to determine the risk factors for SVGD. Many factors contribute to SVGD when the vein is grafted into an arterial environment, such as surgery-related factors, smoking, diabetes mellitus, hyperlipidemia, and others. In this review, we discuss the risk factors for SVGD, current surgical and pharmacologic therapies with which to manage SVGD, and the prevention of SVGD.

Noncoding RNAs as therapeutic targets in atherosclerosis with diabetes mellitus

Atherosclerosis is one of the major macrovascular complications of diabetes mellitus (DM), and it is the main cause of death from clinical observation. Among various cell types involved in this disorder, endothelial cells, vascular smooth muscle cells (VSMCs), and macrophages play a crucial role in the occurrence and development of this disease. The regulation and stabilization of these cells are a key therapeutic strategy for DM-associated atherosclerosis. An increasing number of evidences implicate that various types of noncoding RNAs (ncRNAs) play a vital role in many cellular responses as well as in physiological and pathological processes of atherosclerosis and DM that drive atherogenic/antiatherogenic processes in those cells. Encouragingly, many ncRNAs have already been tested in animal experiments or clinical trials showing good performance. In this review, we summarize recent progresses in research on functional regulatory role of ncRNAs in atherosclerosis with DM. More importantly, we illustrate new thoughts and findings relevant to ncRNAs as potential therapeutic targets or biomarkers for atherosclerosis with DM.

MiR-551b-5p Contributes to Pathogenesis of Vein Graft Failure via Upregulating Early Growth Response-1 Expression

Background:

Vein graft failure (VGF) is a serious complication of coronary artery bypass graft, although the mechanism remains unclear. The study aimed to investigate the effects of microRNAs (miRNAs) on the endothelial dysfunction involved in VGF.

Methods:

Human umbilical vein endothelial cells (HUVECs) were subjected to mechanical stretch stimulation to induce endothelial dysfunction. Genome-wide transcriptome profiling was performed using the Human miRNA OneArray^® V4 (PhalanxBio Inc., San Diego, USA). The miRNA-messenger RNA (mRNA) network was investigated using gene ontology and Kyoto Encyclopedia of Genes and Genomes. The miR-551b-5p mimic and inhibitor were applied to regulate miR-551b-5p expression in the HUVECs. The 5-ethynyl-2’-deoxyuridine assay, polymerase chain reaction (PCR), and Western blotting (WB) were used to assess HUVECs proliferation, mRNA expression, and protein expression, respectively. The vein graft model was established in early growth response (Egr)-1 knockout (KO) mice and wide-type (WT) C57BL/6J mice for pathological and immunohistochemical analysis. Endothelial cells isolated from the veins of WT and Egr-1 KO mice were subjected to mechanical stretch stimulation; PCR and WB were conducted to confirm the regulatory effect of Egr-1 on Intercellular adhesion molecule (Icam-1). One-way analysis of variance and independent t-test were performed for data analysis.

Results:

Thirty-eight miRNAs were differentially expressed in HUVECs after mechanical stretch stimulation. The bioinformatics analysis revealed that Egr-1 might be involved in VGF and was a potential target gene of miR-551b-5p. The mechanical stretch stimulation increased miR-551b-5p expression by 2.93 ± 0.08 fold (t = 3.07, P < 0.05), compared with the normal HUVECs. Transfection with the miR-551b-5p mimic or inhibitor increased expression of miR-551b-5p by 793.1 ± 171.6 fold (t = 13.84, P < 0.001) or decreased by 26.3% ± 2.4% (t = 26.39, P < 0.05) in the HUVECs, respectively. HUVECs proliferation and EGR-1 mRNA expression were significantly suppressed by inhibiting miR-551b-5p expression (P < 0.05). The lumens of the vein grafts in the Egr-1 KO mice were wider than that in the WT mice. Icam-1 expression was suppressed significantly in the Egr-1 KO vein grafts (P < 0.05).

Conclusions:

Increased miR-551b-5p expression leads to endothelial dysfunction by upregulating Egr-1 expression. EGR-1 KO can improve the function of a grafted vein through suppressing Icam-1.

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

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

MicroRNA-145 regulates the differentiation of human adipose-derived stem cells to smooth muscle cells via targeting Krüppel-like factor 4

Understanding the molecular mechanisms underlying human adipose-derived stem cell (hASC) differentiation to smooth muscle may contribute to the development of effective therapies for relevant muscle defects, such as bladder wall and urethral defects. A previous study described the differentiation of hASCs to smooth muscle cells (SMCs) by transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein‑4 (BMP4) treatment. The present study investigated whether microRNA-145 (miR‑145) may be involved in the process of hASC differentiation. The expression of miR‑145 was significantly increased during differentiation of ASCs to SMCs. SMC‑specific genes and proteins, including a‑smooth muscle actin (α‑SMA), smooth muscle protein‑22α(SM22α), calponin and myosin heavy chain (SM‑MHC) were upregulated by transfection of a miR‑145 mimic. By contrast, these factors were downregulated following introduction of antisense oligonucleotides. In addition, Krüppel‑like factor 4 (KLF4) levels, which decreased during the differentiation of hASCs, were downregulated when the cells were transfected miR‑145 mimics. Futhermore, inhibition of KLF4 by treatment with short‑interfering‑RNA against KLF4, resulted in increased expression of SMC‑specific genes and proteins. In conclusion, the results of the present study demonstrated that by regulating KLF4, miR‑145 may be involved in regulating smooth muscle differentiation of ASCs induced by TGF‑β1 and BMP4.

MiR-135a Suppresses Calcification in Senescent VSMCs by Regulating KLF4/STAT3 Pathway

Cellular function phenotype is regulated by various microRNAs (miRs), including miR-135a. However, how miR-135a is involved in the calcification in senescent vascular smooth muscle cells (VSMCs) is not clear yet. In the present study, we first identified the significantly altered miRNAs in VSMCs, then performed consecutive passage culture of VSMCs and analyzed the expression of miR-135a and calcification genes in the senescent phase. Next, the effects of the miR-135a inhibition on calcification and calcification genes were analyzed. The luciferase assay was used to validate the target protein of miR-135a. The western blotting was used to determine the effects of miR-135a on Krüppel-like factor 4 (KLF4) and signal transducer and activator of transcription 3 protein (STAT3) expression, as well as the relationship between KLF4 and STAT3. Finally, the quantified cellular calcification was measured to examine the involvement of miR-135a, KLF4 and STAT3 in VSMCs calcification. Our results showed that miR-135a was significantly altered in VSMCs. Cell calcification and calcification genes were greatly altered by miR-135a inhibition. KLF4 was validated as the target RNA of miR-135a. Expression of KLF4 and STAT3 were both significantly decreased by over expressed miR-135a, while the inhibition of miR-135a and KLF4 siRNA both decreased the STAT3 protein levels. Moreover, the inhibition of miR-135a dramatically increased the calcium concentration, but co-treatment with KLF4 or STAT3 siRNA both decreased the calcium concentration. The present study identified miR-135a as a potential osteogenic differentiation suppressor in senescent VSMCs and revealed that KLF4/STAT3 pathway, at least partially, was involved in the mechanism.

Role of noncoding RNA in vascular remodelling

PURPOSE OF REVIEW

Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are becoming fundamentally important in the pathophysiology relating to injury-induced vascular remodelling. We highlight recent studies that demonstrate the involvement of ncRNAs in vein graft disease, in in-stent restenosis and in pulmonary arterial hypertension, with a particular focus on endothelial cell and vascular smooth muscle cell function. We also briefly discuss the emerging role of exosomal-derived ncRNAs and how this mechanism impacts on vascular function.

RECENT FINDINGS

ncRNAs have been described as novel regulators in the pathophysiology of vascular injury, inflammation, and vessel wall remodelling. In particular, several studies have demonstrated that manipulation of miRNAs can reduce the burden of pathological vascular remodelling. Such studies have also shown that exosomal miRNA-mediated, cell-to-cell communication between endothelial cells and vascular smooth muscle cells is critical in the disease process. In addition to miRNAs, lncRNAs are emerging as regulators of vascular function in health and disease. Although lncRNAs are complex in both their sheer numbers and mechanisms of action, identifying their contribution to vascular disease is essential.

SUMMARY

Given the important roles of ncRNAs in vascular injury and remodelling together will their capacity for cell-to-cell communication, manipulating ncRNA might provide novel therapeutic interventions.

Airway smooth muscle inflammation is regulated by microRNA-145 in COPD

Chronic obstructive pulmonary disease (COPD) is a common, highly debilitating disease of the airways, primarily caused by smoking. Chronic inflammation and structural remodelling are key pathological features of this disease, in part caused by the aberrant function of airway smooth muscle (ASM) cells under the regulation of transforming growth factor (TGF)-β. miRNA are short, noncoding gene transcripts involved in the negative regulation of specific target genes, through their interactions with mRNA. Previous studies have proposed that mRNA-145 (miR-145) may interact with SMAD3, an important downstream signalling molecule of the TGF-β pathway. TGF-β was used to stimulate primary human ASM cells isolated from healthy nonsmokers, healthy smokers and COPD patients. This resulted in a TGF-β-dependent increase in CXCL8 and IL-6 release, most notably in the cells from COPD patients. TGF-β stimulation increased SMAD3 expression, only in cells from COPD patients, with a concurrent increased miR-145 expression. Regulation of miR-145 was found to be negatively controlled by pathways involving the MAP kinases, MEK-1/2 and p38 MAPK. Subsequent, overexpression of miR-145 (using synthetic mimics) in ASM cells from patients with COPD suppressed IL-6 and CXCL8 release, to levels comparable to the nonsmoker controls. Therefore, this study suggests that miR-145 negatively regulates pro-inflammatory cytokine release from ASM cells in COPD by targeting SMAD3.

Cardiac Resynchronization Therapy Outcomes in Type 2 Diabetic Patients: Role of MicroRNA Changes

Heart failure (HF) and type 2 diabetes mellitus (T2DM) are two growing and related diseases in general population and particularly in elderly people. In selected patients affected by HF and severe dysfunction of left ventricle ejection fraction (LVEF), with left bundle brunch block, the cardiac resynchronization therapy with a defibrillator (CRT) is the treatment of choice to improve symptoms, NYHA class, and quality of life. CRT effects are related to alterations in genes and microRNAs (miRs) expression, which regulate cardiac processes involved in cardiac apoptosis, cardiac fibrosis, cardiac hypertrophy and angiogenesis, and membrane channel ionic currents. Different studies have shown a different prognosis in T2DM patients and T2DM elderly patients treated by CRT-D. We reviewed the literature data on CRT-D effect on adult and elderly patients with T2DM as compared with nondiabetic patients.

MicroRNA-143/-145 in Cardiovascular Diseases

MicroRNAs (miRNAs) play an essential role in the onset and development of many cardiovascular diseases. Increasing evidence shows that miRNAs can be used as potential diagnostic biomarkers for cardiovascular diseases, and miRNA-based therapy may be a promising therapy for the treatment of cardiovascular diseases. The microRNA-143/-145 (miR-143/-145) cluster is essential for differentiation of vascular smooth muscle cells (VSMCs) and determines VSMC phenotypic switching. In this review, we summarize the recent progress in knowledge concerning the function of miR-143/-145 in the cardiovascular system and their role in cardiovascular diseases. We discuss the potential role of miR-143/-145 as valuable biomarkers for cardiovascular diseases and explore the potential strategy of targeting miR-143 and miR-145.

Noncoding RNAs in diabetes vascular complications

Diabetes mellitus is the most common metabolic disorder and is recognised as a dominant health threat of our time. Diabetes induces a widespread damage of the macro- and microvasculature in different organs and tissues and disrupts the endogenous vascular repair mechanisms, thus causing diffuse and severe complications. Moreover, diabetic patients respond poorly to surgical interventions aiming to "revascularise" (i.e., to restore blood flow supply) the ischemic myocardium or lower limbs. The molecular causes underpinning diabetes vascular complications are still underappreciated and druggable molecular targets for therapeutic interventions have not yet clearly emerged. Moreover, diabetes itself and diabetes complications are often silent killers, requiring new prognostic, diagnostic and predictive biomarkers for use in the clinical practice. Noncoding RNA (ncRNAs) are emerging as new fundamental regulators of gene expression. The small microRNAs (miRNAs, miRs) have opened the field capturing the attention of basic and clinical scientists for their potential to become new therapeutic targets and clinical biomarkers. More recently, long ncRNAs (lncRNAs) have started to be actively investigated, leading to first exciting reports, which further suggest their important and yet largely unexplored contribution to vascular physiology and disease. This review introduces the different ncRNA types and focuses at the ncRNA roles in diabetes vascular complications. Furthermore, we discuss the potential value of ncRNAs as clinical biomarkers, and we examine the possibilities for therapeutic intervention targeting ncRNs in diabetes. This article is part of a Special Issue titled: Non-coding RNAs.