Micro-RNAs in abdominal aortic aneurysms: insights from animal models and relevance to human disease

A bibliometric and visualization analysis of global trends and frontiers on macrophages in abdominal aortic aneurysms research

BACKGROUND

Macrophages are key regulators of the inflammatory and innate immune responses. Researchers have shown that aberrant expression of macrophages contributes to the development of abdominal aortic aneurysms (AAA). However, a comprehensive bibliometric analysis exploring the research status and knowledge mapping of this area is lacking. This study aimed to explore the research status, knowledge mapping and hotspots of macrophages in AAA research from a bibliometric perspective.

METHODS

In this study, we retrieved articles published between 2000 and 2022 on macrophages associated with AAA research from the Web of Science Core Collection (WoSCC) database. The retrieved literature data were further analyzed using Citespace and VOSviewer software.

RESULTS

A total of 918 qualified publications related to AAA-associated macrophages were retrieved. The number of publications in this field has been increasing annually. China and the United States were the 2 main drivers in this field, contributing to more than 64% of the publications. In addition, the US had the most publications, top institutions, and expert researchers, dominating in research on macrophages in AAA. The Harvard University was the most productive institution, with 60 publications. The journal with the most publications was Arteriosclerosis, Thrombosis, and Vascular Biology (86). Daugherty Alan was the most prolific author (28 publications) and he was also the most cited co- author. Furthermore, the exploration of established animal models, macrophage-related inflammatory-microenvironment, macrophage-related immune mechanism, clinical translation and molecular imaging research remained future research directions in this field.

CONCLUSIONS

Our findings offered new insights for scholars in this field. They will help researchers explore new directions for their work.

Deciphering disease signatures and molecular targets in vascular Ehlers-Danlos syndrome through transcriptome and miRNome sequencing of dermal fibroblasts

Vascular Ehlers-Danlos syndrome (vEDS) is a severe connective tissue disorder caused by dominant mutations in the COL3A1 gene encoding type III collagen (COLLIII). COLLIII is primarily found in blood vessels and hollow organs, and its deficiency leads to soft connective tissues fragility, resulting in life-threatening arterial and organ ruptures. There are no current targeted therapies available. Although the disease usually results from COLLIII misfolding due to triple helix structure disruption, the underlying pathomechanisms are largely unknown. To address this knowledge gap, we performed a comprehensive transcriptome analysis using RNA- and miRNA-seq on a large cohort of dermal fibroblasts from vEDS patients and healthy donors. Our investigation revealed an intricate interplay between proteostasis abnormalities, inefficient endoplasmic reticulum stress response, and compromised autophagy, which may significantly impact the molecular pathology. We also present the first detailed miRNAs expression profile in patient cells, demonstrating that several aberrantly expressed miRNAs can disrupt critical cellular functions involved in vEDS pathophysiology, such as autophagy, proteostasis, and mTOR signaling. Target prediction and regulatory networks analyses suggested potential interactions among miRNAs, lncRNAs, and candidate target genes linked to extracellular matrix organization and autophagy-lysosome pathway. Our results highlight the importance of understanding the functional role of ncRNAs in vEDS pathogenesis, shedding light on possible miRNAs and lncRNAs signatures and their functional implications for dysregulated pathways related to disease. Deciphering this complex molecular network of RNA interactions may yield additional evidence for potential disease biomolecules and targets, assisting in the design of effective patient treatment strategies.

Clearance of Stress-Induced Premature Senescent Cells Alleviates the Formation of Abdominal Aortic Aneurysms

Abdominal aortic aneurysm (AAA) is a multifactorial disease characterized by various pathophysiological processes, including chronic inflammation, oxidative stress, and proteolytic activity in the aortic wall. Stress-induced premature senescence (SIPS) has been implicated in regulating these pathophysiological processes, but whether SIPS contributes to AAA formation remains unknown. Here, we detected SIPS in AAA from patients and young mice. The senolytic agent ABT263 prevented AAA development by inhibiting SIPS. Additionally, SIPS promoted the transformation of vascular smooth muscle cells (VSMCs) from a contractile phenotype to a synthetic phenotype, whereas inhibition of SIPS by the senolytic drug ABT263 suppressed VSMC phenotypic switching. RNA sequencing and single-cell RNA sequencing analysis revealed that fibroblast growth factor 9 (FGF9), secreted by stress-induced premature senescent VSMCs, was a key regulator of VSMC phenotypic switching and that FGF9 knockdown abolished this effect. We further showed that the FGF9 level was critical for the activation of PDGFRβ/ERK1/2 signaling, facilitating VSMC phenotypic change. Taken together, our findings demonstrated that SIPS is critical for VSMC phenotypic switching through the activation of FGF9/PDGFRβ/ERK1/2 signaling, promoting AAA development and progression. Thus, targeting SIPS with the senolytic agent ABT263 may be a valuable therapeutic strategy for the prevention or treatment of AAA.

A systematic review and meta-analysis of the diagnostic value of circulating microRNA-17-5p in patients with non-small cell lung cancer

BACKGROUND

nonSmall Cell Lung Cancer (NSCLC) is the most common type of lung cancer with high morbidity and mortality rates. Studies have shown that miR-17-5p levels are significantly increased in the circulating blood of NSCLC patients. This meta-analysis aimed to investigate the diagnostic value of miR-17-5p in NSCLC in China.

METHODS

A literature search was conducted for studies on the correlation between miR-25 and the diagnosis of NSCLC until October 2022 using English and Chinese databases. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was adopted to evaluate the quality of studies in the literature. Numerical values for sensitivity and specificity were obtained from false negative (FN), false positive (FP), true negative (TN), and true positive (TP) rates, presented alongside graphical representations with boxes marking the values and horizontal lines showing the confidence intervals. Summary Receiver Operating Characteristic (SROC) curves were applied to assess the performance of the diagnostic tests. The data were processed using RevMan 5.3.

RESULTS

Three studies (208 cases of NSCLC patients and 198 healthy controls) met our evaluation criteria. The sensitivity was 0.70 to 0.75, and the specificity value was 0.82 to 0.83. The Area Under the Curve (AUC) from the SROC curves was > 80%; therefore, it was classified as a good category.

CONCLUSION

Our meta-analysis shows that miR-17-5p can be used for the diagnosis of NSCLC and may serve as a biomarker for the detection of early NSCLC in the Chinese population.

Patients with abdominal aortic aneurysms have reduced levels of microRNA 122-5p in circulating exosomes

OBJECTIVE

There are currently no specific biomarkers to identify patients with abdominal aortic aneurysms (AAAs). Circulating exosomes contain microRNAs (miRNA) that are potential biomarkers for the presence of disease. This study aimed to characterize the exosomal miRNA expression profile of patients with AAAs in order to identify novel biomarkers of disease.

METHODS

Patients undergoing duplex ultrasound (US) or computed tomography (CT) for screening or surveillance of an AAA were screened to participate in the study. Cases with AAA were defined as having a max aortic diameter >3 cm. Circulating plasma exosomes were isolated using Cushioned-Density Gradient Ultracentrifugation and total RNA was extracted. Next Generation Sequencing was performed on the Illumina HiSeq4000 SE50. Differential miRNA expression analysis was performed using DESeq2 software with a Benjamini-Hochberg correction. MicroRNA expression profiles were validated by Quantitative Real-Time PCR.

RESULTS

A total of 109 patients were screened to participate in the study. Eleven patients with AAA and 15 non-aneurysmal controls met study criteria and were enrolled. Ultrasound measured aortic diameter was significantly larger in the AAA group (mean maximum diameter 4.3 vs 2.0 cm, P = 6.45x10-6). More AAA patients had coronary artery disease (5/11 vs 1/15, P = 0.05) as compared to controls, but the groups did not differ significantly in the rates of peripheral arterial disease and chronic obstructive pulmonary disease. A total of 40 miRNAs were differentially expressed (P<0.05). Of these, 18 miRNAs were downregulated and 22 were upregulated in the AAA group compared to controls. After false discovery rate (FDR) adjustment, only miR-122-5p was expressed at significantly different levels in the AAA group compared to controls (fold change = 5.03 controls vs AAA; raw P = 1.8x10-5; FDR P = 0.02).

CONCLUSION

Plasma exosomes from AAA patients have significantly reduced levels of miRNA-122-5p compared to controls. This is a novel exosome-associated miRNA that warrants further investigation to determine its use as a diagnostic biomarker and potential implications in AAA pathogenesis.

MicroRNA-181a regulates Treg functions via TGF-β1/Smad axis in the spleen of mice with acute gouty arthritis induced by MSU crystals

Regulatory T cells (Tregs) play critical roles in restricting inflammatory pathogenesis and limiting undesirable Th2 response to environmental allergens. However, the role of miR-181a in regulating acute gouty arthritis (AGA) and Treg function remains unclear. This study aimed to investigate the potential roles of miR-181a in Treg immunity and the associated signaling pathway in the AGA mouse model. A solution with monosodium urate (MSU) crystals was injected into the joint tissue of mice to induce AGA. ELISA was used to examine inflammatory factors in blood samples, and flow cytometry was used to analyze Treg profile in mice with MSU-induced AGA. Cell proliferation and viability were assessed by CCK-8 assay. TGF-β1/Smad signaling activation was detected by western blot. We found that miR-181a expression showed a positive correlation with the changes of splenic Tregs percentage in AGA mice. miR-181a regulated the TGF-β1/Smad axis, since the transfection of miR-181a mimic increased the level of TGF-β1 and the phosphorylation of Smad2/3 in Tregs in AGA mice. Additionally, miR-181a mimic also promoted responses of Tregs via TGF-β1 in vitro and in vivo. Our work uncovered a vital role of miR-181a in the immune function of Treg cells by mediating the activity of the TGF-β1/Smad pathway in the AGA mouse model induced by MSU.

Identification of a miRSNP Regulatory Axis in Abdominal Aortic Aneurysm by a Network and Pathway-Based Integrative Analysis

Abdominal aortic aneurysm (AAA) refers to local abnormal expansion of the abdominal aorta and mostly occurs in elderly men. MicroRNA (miRNA) is single-stranded RNA consisting of 18-25 nucleotides. It plays a key role in posttranscriptional gene expression and in the regulation of human functions and disease development. miRNA exerts its function mainly through the binding of complementary base pairs to the 3' regulatory region of mRNA transcripts. Therefore, miRNA-related single-nucleotide polymorphisms (miRSNPs) can affect miRNA expression and processing kinetics. miRSNPs can be classified based on their location: miRSNPs within miRNA-producing genes and miRSNPs within miRNA target genes. Increasing evidence indicates that miRSNPs play an important role in the pathogenic kinetics of cardiovascular diseases. The aim of this study was to identify potential miRNAs and integrate them into a miRSNP-based disease-related pathway network, the results of which are of great significance to the interpretation of the potential mechanisms and functions of miRSNPs in the pathogenesis of diseases.

circPTN Promotes the Progression of Non-Small Cell Lung Cancer through Upregulation of E2F2 by Sponging miR-432-5p

Background

Non-small cell lung cancer (NSCLC) is one of the most prevalent cancers, accounting for around 80% of total lung cancer cases worldwide. Exploring the function and mechanism of circRNAs could provide insights into the diagnosis and treatment for NSCLC.

Methods

In this study, we collected tumor tissues and adjacent normal tissues from NSCLC patients to detect the expression level of circPTN and analyzed the association of its expression level with the clinicopathological parameter of NSCLC patients. Moreover, the functional engagement of circPTN in NSCLC cells was examined by cell counting kit-8 (CCK-8) cell proliferation assay, transwell migration and invasion assays, and tube formation assay. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB) analysis were used to detect gene and protein expression, respectively. The molecular targets of cicrPTN were predicted using starBase online resources, which was validated by RNA immunoprecipitation (RIP) and dual-luciferase reporter assay.

Results

Compared with adjacent normal tissues, there was a remarkable increase of the circPTN levels in NSCLC tissues. A high level of circPTN expression was associated with more lymph node metastasis (LNM) and advanced TNM stages. Functionally, circPTN knockdown inhibited the proliferation, migration, and invasion and tube formation ability of NSCLC cells. We further demonstrated that circPTN regulated the malignant phenotype of NSCLC cells through targeting the miR-432-5p/E2F2 axis.

Conclusion

Together, our results suggest that circPTN, which is upregulated in NSCLC tissues, could serve as a prognostic marker for NSCLC patients. circPTN regulates the malignant progression of NSCLC cells through targeting the miR-432-5p/E2F2 axis, which may be employed as a potential strategy for the management of NSCLC.

Circ_0001897 regulates high glucose-induced angiogenesis and inflammation in retinal microvascular endothelial cells through miR-29c-3p/transforming growth factor beta 2 axis

Diabetic retinopathy (DR) has become the leading cause of blindness among adults at working age. Previous studies have implicated circ_0001897 in the development of DR. In this study, we investigated the functional roles and mechanisms of circ_0001897 in high glucose-induced angiogenesis and inflammation. Peripheral blood samples from DR patients and healthy controls were collected to examine circ_0001897 expression, which demonstrated a significant upregulation of circ_0001897 in DR patients. To investigate the functional role and mechanisms of circ_0001897, human retinal microvascular endothelial cells (HRECs) were treated with high glucose (HG) to establish an in vitro DR model of endothelial cells. HG treatment induced the upregulation of circ_0001897 in HRECs, and enhanced cell proliferation, inflammatory responses, as well as in vitro angiogenesis. Circ_0001897 knockdown significantly attenuated the cell proliferation, inflammatory responses, and angiogenesis induced by HG treatment. Mechanistically, circ_0001897 sponged and inhibited the activity of mir-29c-3p, which in turn regulates the downstream target transforming growth factor beta 2 (TGFB2). The effects of circ_0001897 knockdown could be rescued by mir-29c-3p inhibitor or TGFB2 overexpression. Collectively, our data demonstrated the novel role of circ_0001897/mir-29c-3p/TGFB2 axis in regulating HG-induced inflammation and angiogenesis of HRECs. These findings suggest that targeting circ_0001897 could serve as an intervention strategy to ameliorate DR.

Identification of the Key Genes and Potential Therapeutic Compounds for Abdominal Aortic Aneurysm Based on a Weighted Correlation Network Analysis

Background: There is still an unmet need for therapeutic drugs for patients with an abdominal aortic aneurysm (AAA), especially for candidates unsuitable for surgical or interventional repair. Therefore, the purpose of this in silico study is to identify significant genes and regulatory mechanisms in AAA patients to predicate the potential therapeutic compounds for significant genes. Methods: The GSE57691 dataset was obtained from Gene Expression Omnibus (GEO) and used to identify the differentially expressed genes (DEGs) and weighted correlation network analysis (WGCNA). The biological function of DEGs was determined using gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). AAA-related genes were obtained from the Comparative Toxicogenomics Database (CTD) using the keywords: aortic aneurysm and abdominal. The hub genes in AAA were obtained by overlapping DEGs, WGCNA-based hub genes, and CTD-based genes. The diagnostic values of hub genes were determined using ROC curve analysis. Hereby, a TF-miRNA-hub gene network was constructed based on the miRnet database. Using these data, potential therapeutic compounds for the therapy of AAA were predicted based on the Drug Gene Interaction Database (DGIdb). Results: A total of 218 DEGs (17 upregulated and 201 downregulated) and their biological function were explored; 4093 AAA-related genes were derived by text mining. Three hub modules and 144 hub genes were identified by WGCNA. asparagine synthetase (ASNS), axin-related protein 2 (AXIN2), melanoma cell adhesion molecule (MCAM), and the testis-specific Y-encoded-like protein 1 (TSPYL1) were obtained as intersecting hub genes and the diagnostic values were confirmed with ROC curves. As potential compounds targeting the hub genes, asparaginase was identified as the target compound for ASNS. Prednisolone and abiraterone were identified as compounds targeting TSPYL1. For MCAM and TSPYL1, no potential therapeutic compound could be predicted. Conclusion: Using WGCNA analysis and text mining, pre-existing gene expression data were used to provide novel insight into potential AAA-related protein targets. For two of these targets, compounds could be predicted.

Biomarkers in EndoVascular Aneurysm Repair (EVAR) and Abdominal Aortic Aneurysm: Pathophysiology and Clinical Implications

Circulating biomarkers have been recently investigated among patients undergoing endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). Considering the plethora of small descriptive studies reporting potential associations between biomarkers and clinical outcomes, this review aims to summarize the current literature considering both the treated disease (post EVAR) and the untreated disease (AAA before EVAR). All studies describing outcomes of tissue biomarkers in patients undergoing EVAR and in patients with AAA were included, and references were checked for additional sources. In the EVAR scenario, circulating interleukin-6 (IL-6) is a marker of inflammatory reaction which might predict postoperative morbidity; cystatin C is a promising early marker of post-procedural acute kidney injury; plasma matrix metalloproteinase-9 (MMP-9) concentration after 3 months from EVAR might help in detecting post-procedural endoleak. This review also summarizes the current gaps in knowledge and future direction of this field of research. Among markers used in patients with AAA, galectin and granzyme appear to be promising and should be carefully investigated even in the EVAR setting. Larger prospective trials are required to establish and evaluate prognostic models with highest values with these markers.

Maternal High-Fat Diet Promotes Abdominal Aortic Aneurysm Expansion in Adult Offspring by Epigenetic Regulation of IRF8-Mediated Osteoclast-like Macrophage Differentiation

Maternal high-fat diet (HFD) modulates vascular remodeling in adult offspring. Here, we investigated the impact of maternal HFD on abdominal aortic aneurysm (AAA) development. Female wild-type mice were fed an HFD or normal diet (ND). AAA was induced in eight-week-old pups using calcium chloride. Male offspring of HFD-fed dams (O-HFD) showed a significant enlargement in AAA compared with the offspring of ND-fed dams (O-ND). Positive-staining cells for tartrate-resistant acid phosphate (TRAP) and matrix metalloproteinase (MMP) activity were significantly increased in O-HFD. The pharmacological inhibition of osteoclastogenesis abolished the exaggerated AAA development in O-HFD. The in vitro tumor necrosis factor-α-induced osteoclast-like differentiation of bone marrow-derived macrophages showed a higher number of TRAP-positive cells and osteoclast-specific gene expressions in O-HFD. Consistent with an increased expression of nuclear factor of activated T cells 1 (NFATc1) in O-HFD, the nuclear protein expression of interferon regulatory factor 8 (IRF8), a transcriptional repressor, were much lower, with significantly increased H3K27me3 marks at the promoter region. The enhancer of zeste homolog 2 inhibitor treatment restored IRF8 expression, resulting in no difference in NFATc1 and TRAP expressions between the two groups. Our findings demonstrate that maternal HFD augments AAA expansion, accompanied by exaggerated osteoclast-like macrophage accumulation, suggesting the possibility of macrophage skewing via epigenetic reprogramming.

Role of microRNA-25 in high glucose cultured Müller glia

AIM

To investigate the role of microRNA-25 (miR-25) in proliferation and apoptosis of retinal Müller glia (MG) under high glucose condition.

METHODS

The purity of the cultured cells was verified by immunocytochemistry and flow cytometry using antibodies that specifically recognized MG. The expression level of miR-25 under normal and high glucose conditions were validated by quantitative reverse transcription polymerase chain reaction (RT-qPCR). miR-25 mimics and negative control were transfected into MG and multiple functional experiments including cell counting kit-8 assay, EDU assay, and flow cytometry were conducted to explore the effects of miR-25 on the proliferation and apoptosis of high glucose cultured MG (HGMG).

RESULTS

Immunocytochemistry and flow cytometry confirmed the high purity of primary cultured MG. RT-PCR results showed that the expression level of miR-25 was significantly repressed in HGMG, while over-expression of miR-25 by miR-25 mimic markedly inhibited the high glucose induced cell apoptosis and promoted the proliferation of MG.

CONCLUSION

The expression level of miR-25 is significantly downregulated in HGMG and its overexpression could attenuate the high glucose damages on MG by promoting proliferation and reducing apoptosis.

miR-200-3p suppresses cell proliferation and reduces apoptosis in diabetic retinopathy via blocking the TGF-β2/Smad pathway

Increasing evidence has shown that microRNAs (miRNAs) play an important role in the pathogenesis of diabetic retinopathy (DR). However, the role and mechanism of miRNA in regulating high glucose (HG)-induced ARPE-19 cell injury are still not well understood. The present study aimed to investigate the effects of miR-200a-3p on DR progression and reveal the underlying mechanisms of their effects. In the present study, we observed that miR-200a-3p was significantly decreased, while transforming growth factor-β2 (TGF-β2) expression was up-regulated in ARPE-19 cells treated with HG and retina tissues of DR rats. Subsequently, overexpression of miR-200a-3p significantly promoted cell proliferation, reduced apoptosis, as well as inhibited the levels of inflammatory cytokines secreted, matrix metalloprotease 2/9 (MMP2/9), and vascular endothelial growth factor (VEGF) in HG-injured ARPE-19 cells. Moreover, miR-200a-3p was proved to target TGF-β2 mRNA by binding to its 3′ untranslated region (3′UTR) using a luciferase reporter assay. Mechanistically, overexpression of miR-200a-3p reduced HG-induced ARPE-19 cell injury and reduced inflammatory cytokines secreted, as well as down-regulated the expression of VEGF via inactivation of the TGF-β2/Smad pathway in vitro. In vivo experiments, up-regulation of miR-200a-3p ameliorated retinal neovascularization and inflammation of DR rats. In conclusion, our findings demonstrated that miR-200a-3p-elevated prevented DR progression by blocking the TGF-β2/Smad pathway, providing a new therapeutic biomarker for DR treatment in the clinic.

MicroRNA-194 acts as a suppressor during abdominal aortic aneurysm via inhibition of KDM3A-mediated BNIP3

AIMS

Abdominal aortic aneurysm (AAA) is a serious disorder with a high disability rates and mortality rates. Accumulating evidence has identified the vital functions of microRNAs (miRNAs) in the treatment of AAA. Hence, this study is aimed at exploring the modulatory role of miR-194 in the development of AAA.

MAIN METHODS

After the establishment of mouse AAA models, the expression of miR-194 was determined by quantitative reverse transcription polymerase chain reaction (RT-qPCR), while lysine demethylase 3A (KDM3A) was determined by Western blot analysis in vascular smooth muscle cells (VSMCs) from the abdominal aorta. Cell apoptosis, levels of inflammatory factors as well as expressions of matrix metallopeptidase 2 (MMP2) and matrix metallopeptidase 9 (MMP9) were measured after altering the expression of miR-194 and KDM3A in VSMCs. Moreover, the interactions among miR-194, KDM3A, and BCL2 interacting protein 3 (BNIP3) were investigated by chromatin immunoprecipitation (ChIP) assay and dual-luciferase reporter gene assay.

KEY FINDINGS

miR-194 was poorly expressed while the expression of KDM3A was up-regulated in mice with AAA. miR-194 inhibited the expression of KDM3A while BNIP3 was positively mediated by KDM3A. More importantly, the number of macrophages was significantly reduced whereas the rate of apoptosis in VSMCs was enhanced. miR-194 reduced the inflammatory response and oxidative stress by repressing KDM3A-mediated BNIP3 expression.

SIGNIFICANCES

miR-194 played a suppressive role in the progression of AAA by inhibiting the expression of BNIP3 via KDM3A, representing a promising target for AAA management.

Identification of a Plasma Microrna Signature as Biomarker of Subaneurysmal Aortic Dilation in Patients with High Cardiovascular Risk

Patients with subaneurysmal aortic dilation (SAD; 25–29 mm diameter) are likely to progress to true abdominal aortic aneurysm (AAA). Despite these patients having a higher risk of all-cause mortality than subjects with aortic size <24 mm, early diagnostic biomarkers are lacking. MicroRNAs (miRs) are well-recognized potential biomarkers due to their differential expression in different tissues and their stability in blood. We have investigated whether a plasma miRs profile could identify the presence of SAD in high cardiovascular risk patients. Using qRT-PCR arrays in plasma samples, we determined miRs differentially expressed between SAD patients and patients with normal aortic diameter. We then selected 12 miRs to be investigated as biomarkers by construction of ROC curves. A total of 82 significantly differentially expressed miRs were found by qPCR array, and 12 were validated by qRT-PCR. ROC curve analyses showed that seven selected miRs (miR-28-3p, miR-29a-3p, miR-93-3p, miR-150-5p, miR-338-3p, miR-339-3p, and miR-378a-3p) could be valuable biomarkers for distinguishing SAD patients. MiR-339-3p showed the best sensitivity and specificity, even after combination with other miRs. Decreased miR-339-3p expression was associated with increased aortic abdominal diameter. MiR-339-3p, alone or in combination with other miRs, could be used for SAD screening in high cardiovascular risk patients, helping to the early diagnosis of asymptomatic AAA.

Identification of Novel microRNA Profiles Dysregulated in Plasma and Tissue of Abdominal Aortic Aneurysm Patients

microRNAs (miRNAs) are small RNAs that regulate different biological processes. Our objective was to identify miRNAs dysregulated in plasma and tissue of patients with abdominal aortic aneurysm (AAA) and explore new potential targets involved in AAA. Fifty-seven subjects were recruited for a plasma study (30 AAA patients, 16 healthy volunteers and 11 patients with atherosclerosis). The expression level of 179 miRNAs was screened in plasma from a subset of samples, and dysregulated miRNAs were validated in the entire study population. Dysregulated miRNAs were also quantified in aortic tissue of 21 AAA patients and 8 organ donors. Applying a gene set enrichment analysis, an interaction map of dysregulated miRNAs and their targets was built, and selected targets were quantified in tissue samples. miR-27b-3p and miR-221-3p were overexpressed in plasma of AAA patients compared with healthy controls, 1.6 times and 1.9 times, respectively. In AAA tissue, six miRNAs (miR-1, miR-27b-3p, miR-29b-3p, miR-133a-3p, miR-133b, and miR-195-5p) were underexpressed from 1.6 to 4.8 times and four miRNAs (miR-146a-5p, miR-21-5p, miR-144-3p, and miR-103a-3p) were overexpressed from 1.3 to 7.2 times. Thrombospondin-2, a target of miR-195-5p, was increased in AAA tissue and negatively correlated with the expression of miR-195-5p, suggesting their involvement in a common regulatory mechanism.

Dysregulation of microRNA Modulatory Network in Abdominal Aortic Aneurysm

Abdominal artery aneurysm (AAA) refers to abdominal aortic dilatation of 3 cm or greater. AAA is frequently underdiagnosed due to often asymptomatic character of the disease, leading to elevated mortality due to aneurysm rupture. MiRNA constitute a pool of small RNAs controlling gene expression and is involved in many pathologic conditions in human. Targeted panel detecting altered expression of miRNA and genes involved in AAA would improve early diagnosis of this disease. In the presented study, we selected and analyzed miRNA and gene expression signatures in AAA patients. Next, generation sequencing was applied to obtain miRNA and gene-wide expression profiles from peripheral blood mononuclear cells in individuals with AAA and healthy controls. Differential expression analysis was performed using DESeq2 and uninformative variable elimination by partial least squares (UVE-PLS) methods. A total of 31 miRNAs and 51 genes were selected as the most promising biomarkers of AAA. Receiver operating characteristics (ROC) analysis showed good diagnostic ability of proposed biomarkers. Genes regulated by selected miRNAs were determined in silico and associated with functional terms closely related to cardiovascular and neurological diseases. Proposed biomarkers may be used for new diagnostic and therapeutic approaches in management of AAA. The findings will also contribute to the pool of knowledge about miRNA-dependent regulatory mechanisms involved in pathology of that disease.

miR-146a regulates inflammation and development in patients with abdominal aortic aneurysms by targeting CARD10

BACKGROUND

We present the expression of miR-146a in abdominal aortic aneurysms (AAA) patients, and its mechanism for regulating inflammation and development in AAA patients.

METHODS

The expression of miR-146a in serum, PBMC, and abdominal aorta tissues was measured in AAA patients.

RESULTS

We found that level of miR-146a in the serum and its expression in AAA tissues were significantly higher than that in healthy people or normal abdominal aorta tissues. Pearson's method analysis showed that miRNA-146a in the serum of AAA patients was negatively correlated with serum TNF-α, IFN-γ and CRP, and was positively correlated with serum IL-10. The luciferase reporter gene system confirmed that miR-146a targeted inhibition of CARD10 expression in THP-1 and human umbilical vein endothelial cells (HUVECs), and miR-146a was negatively correlated with the expression of CARD10 in the tissues/PBMC of AAA patients. In PBMC of healthy people, over-expression of miR-146a by transferring miR-146a-mimic could increase the expression of SIRT1 but decreased the expression of p65 and the level of TNF-α secretion. Moreover, HUVECs cellular activity change by TNF-α in a dose-dependent manner.

CONCLUSIONS

These results suggested that miR-146a suppressed the inflammation of peripheral blood in AAA patients by targeting CARD10, and miR-146a blocked the progression of AAA through CARD10/SIRT1/p65 pathway.

Identification of key microRNAs and genes associated with abdominal aortic aneurysm based on the gene expression profile

NEW FINDINGS

What is the central question of this study? The aim was to identify abdominal aortic aneurysm (AAA)-associated microRNAs and their target genes in AAA using microarray analysis. What is the main finding and its importance? The main finding was that miR-145 and miR-30c-2* were found to be downregulated microRNAs in AAA, which could exert suppressive effects on AAA progression, and that miR-145 might target RAC2, whereas miR-30c-2* might target PIK3CD, IL1B and RAC2. The findings obtained from the study provide an enhanced understanding of microRNA as a therapeutic target to limit AAA.

ABSTRACT

The aim of the study was to identify abdominal aortic aneurysm (AAA)-associated microRNAs (miRNAs) and genes potentially contributing to AAA. Differential analysis was performed to screen out differentially expressed genes (DEGs) and miRNAs in expression datasets of AAA-related miRNAs [GSE51226 (mouse)] and genes [GSE51227 (mouse) and GSE7084 (human)]. Then, gene ontology (GO) enrichment analysis of DEGs was compared with aneurysm-related GO to screen out DEGs related to the disease. The target genes of differential miRNAs were predicted and used to construct a miRNA-DEG regulatory network, followed by Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of target genes. Moreover, the protein-protein interaction network of target genes of miRNAs in the core position (hub-miRNA) with AAA-related genes was constructed to screen out hub genes. Finally, the target relationship between hub-miRNAs and their target genes was verified. There were 20 upregulated miRNAs and 20 downregulated miRNAs in AAA screened from the GSE51226 dataset (mouse). In addition, there were 1154 upregulated genes and 821 downregulated genes in the GSE51227 dataset (mouse), of which 246 DEGs were enriched in aneurysm-related GO entries in AAA. miR-145 and miR-30c-2* were the key miRNAs of AAA, both of which were downregulated in AAA and influenced pathways so as to affect AAA by regulating their respective target genes. The disease-related gene ACTA2 was downregulated, whereas DEGs including PIK3CD, IL1B, RAC2 and SELL were upregulated in AAA. Finally, it was proved that miR-145 targeted RAC2 and SELL, whereas miR-30c-2* targeted PIK3CD, IL1B and RAC2. Taken together, miR-145 and miR-30c-2*, downregulated in AAA, could potentially affect AAA, and miR-145 might target RAC2, whereas miR-30c-2* might target PIK3CD, IL1B and RAC2.

Tissue-Specific miRNAs Regulate the Development of Thoracic Aortic Aneurysm: The Emerging Role of KLF4 Network

MicroRNAs (miRNAs) are critical regulators of the functional pathways involved in the pathogenesis of cardiovascular diseases. Understanding of the disease-associated alterations in tissue and plasma will elucidate the roles of miRNA in modulation of gene expression throughout development of sporadic non-syndromic ascending thoracic aortic aneurysm (TAA). This will allow one to propose relevant biomarkers for diagnosis or new therapeutic targets for the treatment. The high-throughput sequencing revealed 20 and 17 TAA-specific miRNAs in tissue and plasma samples, respectively. qRT-PCR analysis in extended cohort revealed sex-related differences in miR-10a-5p, miR-126-3p, miR-155-5p and miR-148a-3p expression, which were the most significantly dysregulated in TAA tissues of male patients. Unexpectedly, the set of aneurysm-related miRNAs in TAA plasma did not resemble the tissue signature suggesting more complex organism response to the disease. Three of TAA-specific plasma miRNAs were found to be restored to normal level after aortic surgery, further signifying their relationship to the pathology. The panel of two plasma miRNAs, miR-122-3p, and miR-483-3p, could serve as a potential biomarker set (AUC = 0.84) for the ascending TAA. The miRNA-target enrichment analysis exposed TGF-β signaling pathway as sturdily affected by abnormally expressed miRNAs in the TAA tissue. Nearly half of TAA-specific miRNAs potentially regulate a key component in TGF-β signaling: TGF-β receptors, SMADs and KLF4. Indeed, using immunohistochemistry analysis we detected increased KLF4 expression in 27% of TAA cells compared to 10% of non-TAA cells. In addition, qRT-PCR demonstrated a significant upregulation of ALK1 mRNA expression in TAA tissues. Overall, these observations indicate that the alterations in miRNA expression are sex-dependent and play an essential role in TAA via TGF-β signaling.

Copper Transporter ATP7A (Copper-Transporting P-Type ATPase/Menkes ATPase) Limits Vascular Inflammation and Aortic Aneurysm Development: Role of MicroRNA-125b

OBJECTIVE

Copper (Cu) is essential micronutrient, and its dysregulation is implicated in aortic aneurysm (AA) development. The Cu exporter ATP7A (copper-transporting P-type ATPase/Menkes ATPase) delivers Cu via the Cu chaperone Atox1 (antioxidant 1) to secretory Cu enzymes, such as lysyl oxidase, and excludes excess Cu. Lysyl oxidase is shown to protect against AA formation. However, the role and mechanism of ATP7A in AA pathogenesis remain unknown. Approach and Results: Here, we show that Cu chelator markedly inhibited Ang II (angiotensin II)-induced abdominal AA (AAA) in which ATP7A expression was markedly downregulated. Transgenic ATP7A overexpression prevented Ang II-induced AAA formation. Conversely, Cu transport dysfunctional ATP7A^mut/+/ApoE^-/- mice exhibited robust AAA formation and dissection, excess aortic Cu accumulation as assessed by X-ray fluorescence microscopy, and reduced lysyl oxidase activity. In contrast, AAA formation was not observed in Atox1^-/-/ApoE^-/- mice, suggesting that decreased lysyl oxidase activity, which depends on both ATP7A and Atox1, was not sufficient to develop AAA. Bone marrow transplantation suggested importance of ATP7A in vascular cells, not bone marrow cells, in AAA development. MicroRNA (miR) array identified miR-125b as a highly upregulated miR in AAA from ATP7A^mut/+/ApoE^-/- mice. Furthermore, miR-125b target genes (histone methyltransferase Suv39h1 and the NF-κB negative regulator TNFAIP3 [tumor necrosis factor alpha induced protein 3]) were downregulated, which resulted in increased proinflammatory cytokine expression, aortic macrophage recruitment, MMP (matrix metalloproteinase)-2/9 activity, elastin fragmentation, and vascular smooth muscle cell loss in ATP7A^mut/+/ApoE^-/- mice and reversed by locked nucleic acid-anti-miR-125b infusion.

CONCLUSIONS

ATP7A downregulation/dysfunction promotes AAA formation via upregulating miR-125b, which augments proinflammatory signaling in a Cu-dependent manner. Thus, ATP7A is a potential therapeutic target for inflammatory vascular disease.

Dysregulation of microRNAs and target genes networks in human abdominal aortic aneurysm tissues

BACKGROUND

Abdominal aortic aneurysm (AAA) is a pathological enlargement of infrarenal aorta close to the aortic bifurcation, and it is an important cause of mortality in the elderly. Therefore, the biomarker identification for early diagnosis is of great interest for clinical benefit. It is known that microRNAs (miRNAs) have important roles via target genes regulation in many diseases. This study aimed to identify miRNAs and their target genes involved in the pathogenesis of AAA.

METHODS

Tissue samples were obtained from patients who underwent AAA surgery and from organ donors (control group). Quantitative PCR Array was applied to assess 84 genes and 384 miRNAs aiming to identify differentially expressed targets (AAA n = 6, control n = 6), followed by validation in a new cohort (AAA n = 18, control n = 6) by regular qPCR. The functional interaction between validated miRNAs and target genes was performed by the Ingenuity Pathway Analysis (IPA) software.

RESULTS

The screening cohort assessed by PCR array identified 10 genes and 59 miRNAs differentially expressed (≥2-fold change, p<0.05). Among these, IPA identified 5 genes and 9 miRNAs with paired interaction. ALOX5, PTGIS, CX3CL1 genes, and miR-193a-3p, 125b-5p, 150-5p maintained a statistical significance in the validation cohort. IPA analysis based on the validated genes and miRNAs revealed that eicosanoid and metalloproteinase/TIMP synthesis are potentially involved in AAA.

CONCLUSION

Paired interactions of differentially expressed ALOX5, PTGIS, CX3CL1 genes, and miR-193b-3p, 125b-5p, 150-5p revealed a potentially significant role of the eicosanoid synthesis and metalloproteinase/TIMP pathways in the AAA pathogenesis.

Molecular Pharmacological Approaches for Treating Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is considered to be a potent life-threatening disorder in elderly individuals. Although many patients with a small AAA are detected during routine abdominal screening, there is no effective therapeutic option to prevent the progression or regression of AAA in the clinical setting. Recent advances in molecular biology have led to the identification of several important molecules, including microRNA and transcription factor, in the process of AAA formation. Regulation of these factors using nucleic acid drugs is expected to be a novel therapeutic option for AAA. Nucleic acid drugs can bind to target factors, mRNA, microRNA, and transcription factors in a sequence-specific fashion, resulting in a loss of function of the target molecule at the transcriptional or posttranscriptional level. Of note, inhibition of a transcription factor using a decoy strategy effectively suppresses experimental AAA formation, by regulating the expression of several genes associated with the disease progression. This review focuses on recent advances in molecular therapy of using nucleic acid drugs to treat AAA.

miR-33-5p knockdown attenuates abdominal aortic aneurysm progression via promoting target adenosine triphosphate-binding cassette transporter A1 expression and activating the PI3K/Akt signaling pathway

PURPOSE

The aim of this study was to investigate the role of miR-33-5p in abdominal aortic aneurysm progression, which regulated adenosine triphosphate-binding cassette transporter A1 (ABCA1)-mediated cholesterol efflux and lipid accumulation in THP-1 macrophage-derived foam cells through the PI3K/Akt pathway.

METHODS

Quantitative reverse transcription polymerase chain reaction was used to evaluate the expression level of miR-33-5p and ABCA1 mRNA in abdominal aortic aneurysm patient and normal person tissues. The relationship between miR-33-5p and ABCA1 was examined by dual luciferase report assay. High-performance liquid chromatography was used to evaluate the levels of cholesterol contents. Cholesterol efflux detection was performed by liquid scintillator. The expression of inflammatory cytokines was detected by quantitative reverse transcription polymerase chain reaction. Western blot was applied to determine the expression levels of ABCA1, PI3K (p-PI3K), and Akt (p-Akt).

RESULTS

The quantitative reverse transcription polymerase chain reaction analysis results revealed miR-33-5p overexpression in abdominal aortic aneurysm tissues, but the expression level of ABCA1 was lower in abdominal aortic aneurysm tissues than non-abdominal aortic aneurysm tissues. Subsequently, the dual luciferase report gene assay confirmed that ABCA1 was a target of miR-33-5p, and miR-33-5p-negative regulated ABCA1 expression. Moreover, the expression levels of p-PI3K, p-Akt, and ABCA1 were decreased in THP-1 cell transferred with ABCA1 siRNA, but knockdown of miR-33-5p had an opposite effect. Furthermore, knockdown of miR-33-5p decreased the expression of MMP-2, MMP-9, TNF-α, total cellular cholesterol, and promoted cholesterol efflux in THP-1-derived foam cells. Importantly, LY294002 (PI3K inhibitor) or si-ABCA1 completely inhibited the stimulatory effects of miR-33-5p inhibitor.

CONCLUSION

This study has found that knockdown of miR-33-5p induced ABCA1 expression and promoted inflammatory cytokines and cholesterol efflux likely via activating the PI3K/Akt signaling pathway.

Regulatory Mechanism of MicroRNA-145 in the Pathogenesis of Acute Aortic Dissection

PURPOSE

Previous studies have confirmed that microRNAs play important roles in the pathogenesis of acute aortic dissection (AAD). Here, we aimed to explore the role of miR-145 and its regulatory mechanism in the pathogenesis of AAD.

MATERIALS AND METHODS

AAD tissue samples were harvested from patients with aortic dissection and normal donors. Rat aortic vascular smooth muscle cells (VSMCs) were transfected with miR-145 mimic/inhibitor or negative control mimic/inhibitor. Gene and protein expression was measured in human aortic dissection tissue specimens and VSMCs by qRT-PCR and Western blot. Luciferase reporter assay was applied to verify whether connective tissue growth factor (CTGF) was a direct target of miR-145 in VSMCs. Methyl thiazolyl tetrazolium assay was used to detect VSMC viability.

RESULTS

miR-145 expression was downregulated in aortic dissection tissues and was associated with the survival of patients with AAD. Overexpression of miR-145 promoted VSMC proliferation and inhibited cell apoptosis. Moreover, CTGF, which was increased in aortic dissection tissues, was decreased by miR-145 mimic and increased by miR-145 inhibitor. Furthermore, CTGF was confirmed as a target of miR-145 and could reverse the promotion effect of miR-145 on the progression of AAD.

CONCLUSION

miR-145 suppressed the progression of AAD by targeting CTGF, suggesting that a miR-145/CTGF axis may provide a potential therapeutic target for AAD.

Pathophisiology of abdominal aortic aneurysm: biomarkers and novel therapeutic targets

Abdominal aortic aneurysm (AAA) is a vascular pathology with a high rate of morbidity and mortality and a prevalence that, in men over 65 years, can reach around 8%. In this disease, usually asymptomatic, there is a progressive dilatation of the vascular wall that can lead to its rupture, a fatal phenomenon in more than 80% of cases. The treatment of patients with asymptomatic aneurysms is limited to periodic monitoring with imaging tests, control of cardiovascular risk factors and treatment with statins and antiplatelet therapy. There is no effective pharmacological treatment capable of limiting AAA progression or avoiding their rupture. At present, the aortic diameter is the only marker of risk of rupture and determines the need for surgical repair when it reaches values greater than 5.5cm. This review addresses the main aspects related to epidemiology, risk factors, diagnosis and clinical management of AAA, exposes the difficulties to have good biomarkers of this pathology and describes the strategies for the identification of new therapeutic targets and biomarkers in AAA.

Endothelial Progenitor Cells: New Targets for Therapeutics for Inflammatory Conditions With High Cardiovascular Risk

Over the past decade, we have witnessed an exponential growth of interest into the role of endothelial progenitor cells (EPCs) in cardiovascular disease. While the major thinking revolves around EPC angiogenic repair properties, we have used a hypothesis-driven approach to discover disease-related defects in their characteristics and based on these findings, have identified opportunities for functional enhancement, which offer an exciting avenue for translation into clinical intervention. In this review, we focus on two groups; circulating myeloid angiogenic cells (MACs) and late outgrowth endothelial colony forming cells (ECFCs), and will discuss the unique properties and defects of each population, as new insights have been gained into the potential function of each sub-type using current techniques and multiomic technology. We will discuss their role in inflammatory disorders and alterations in mitochondrial function. In addition, we share key insights into the glycocalyx, and propose this network of membrane-bound proteoglycans and glycoproteins, covering the endothelium warrants further investigation in order to clarify its significance in ECFC regulation of vascularization and angiogenesis and ultimately for potential translational therapeutic aspects.

Genetic Ablation of MicroRNA-33 Attenuates Inflammation and Abdominal Aortic Aneurysm Formation via Several Anti-Inflammatory Pathways

OBJECTIVE

Abdominal aortic aneurysm (AAA) is an increasingly prevalent and ultimately fatal disease with no effective pharmacological treatment. Because matrix degradation induced by vascular inflammation is the major pathophysiology of AAA, attenuation of this inflammation may improve its outcome. Previous studies suggested that miR-33 (microRNA-33) inhibition and genetic ablation of miR-33 increased serum high-density lipoprotein cholesterol and attenuated atherosclerosis.

APPROACH AND RESULTS

MiR-33a-5p expression in central zone of human AAA was higher than marginal zone. MiR-33 deletion attenuated AAA formation in both mouse models of angiotensin II- and calcium chloride-induced AAA. Reduced macrophage accumulation and monocyte chemotactic protein-1 expression were observed in calcium chloride-induced AAA walls in miR-33^-/- mice. In vitro experiments revealed that peritoneal macrophages from miR-33^-/- mice showed reduced matrix metalloproteinase 9 expression levels via c-Jun N-terminal kinase inactivation. Primary aortic vascular smooth muscle cells from miR-33^-/- mice showed reduced monocyte chemotactic protein-1 expression by p38 mitogen-activated protein kinase attenuation. Both of the inactivation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase were possibly because of the increase of ATP-binding cassette transporter A1 that is a well-known target of miR-33. Moreover, high-density lipoprotein cholesterol derived from miR-33^-/- mice reduced expression of matrix metalloproteinase 9 in macrophages and monocyte chemotactic protein-1 in vascular smooth muscle cells. Bone marrow transplantation experiments indicated that miR-33-deficient bone marrow cells ameliorated AAA formation in wild-type recipients. MiR-33 deficiency in recipient mice was also shown to contribute the inhibition of AAA formation.

CONCLUSIONS

These data strongly suggest that inhibition of miR-33 will be effective as a novel strategy for treating AAA.

Role of MicroRNA-103a Targeting ADAM10 in Abdominal Aortic Aneurysm

MicroRNAs (miRNAs) are deregulated in various vascular ailments including abdominal aortic aneurysm (AAA). MiR-103 is involved in vascular, metabolic, and malignant diseases, but whether it participates in the pathogenesis of AAA remains elusive. ADAM10 plays a vital role in the formation of aneurysm, but whether miRs modulate its activity during AAA formation is totally unknown. In this study, we detected the significantly increased protein expression of ADAM10 in angiotensin II induced murine AAA specimens, while the mRNA expression of ADAM10 was similar between AAA and control, suggesting the posttranscriptional regulation. The ADAM10 specific inhibitor GI254023X dramatically reduced the macrophage infiltration of murine abdominal aorta. Bioinformatic predictions suggest that ADAM10 is the target of miR-103a/107 but the binding site is exclusive. At the cellular level, miR-103a-1 suppressed the protein expression of ADAM10, while antisense miR-103a-1 increased its expression. Particularly, with the progression of murine AAA, the mRNA expression of miR-103a/107 substantially decreased and the protein expression of ADAM10 greatly increased. Together, our data afford the new insight that miR-103a inhibited AAA growth via targeting ADAM10, which might be a promising therapeutic strategy to alleviate AAA.

Screening of circulating microRNA biomarkers for prevalence of abdominal aortic aneurysm and aneurysm growth

BACKGROUND AND AIMS

MicroRNA (miR) are important regulators of gene expression and biological processes and have recently been suggested as possible biomarkers for abdominal aortic aneurysm (AAA) disease. The aim of the present study was to assess the role of miR as biomarkers for initiation and progression of AAA disease, through evaluation of a wide range of miRs in a large population-based cohort, with AAA patients with linked clinical data regarding risk factors, AAA size and growth, as well as controls.

METHODS

The expression of the 172 most commonly expressed miRs in plasma was analyzed by real-time PCR in samples from 169 screening-detected AAA patients and 48 age-matched controls.

RESULTS

For 103 miRs, there was a significant difference in expression between AAA and controls. Of these, 20 miRs were differently expressed between fast and slow growing aneurysms. These miRs target genes known to be involved in AAA disease as well as novel genes and pathways. By combining the top altered miRs together with clinical variables, strong predictive values, determining growth of AAA, were obtained (area under curve = 0.86, p < 0.001).

CONCLUSIONS

This large cohort study identified several novel miRs with altered expression in AAA patients when compared to controls. Assessment of miR expression may offer an opportunity to predict disease progression and aneurysm growth.

MicroRNA-181b Controls Atherosclerosis and Aneurysms Through Regulation of TIMP-3 and Elastin

Supplemental Digital Content is available in the text.

Rationale:

Atherosclerosis and aneurysms are leading causes of mortality worldwide. MicroRNAs (miRs) are key determinants of gene and protein expression, and atypical miR expression has been associated with many cardiovascular diseases; although their contributory role to atherosclerotic plaque and abdominal aortic aneurysm stability are poorly understood.

Objective:

To investigate whether miR-181b regulates tissue inhibitor of metalloproteinase-3 expression and affects atherosclerosis and aneurysms.

Methods and Results:

Here, we demonstrate that miR-181b was overexpressed in symptomatic human atherosclerotic plaques and abdominal aortic aneurysms and correlated with decreased expression of predicted miR-181b targets, tissue inhibitor of metalloproteinase-3, and elastin. Using the well-characterized mouse atherosclerosis models of Apoe^−/− and Ldlr^−/−, we observed that in vivo administration of locked nucleic acid anti-miR-181b retarded both the development and the progression of atherosclerotic plaques. Systemic delivery of anti-miR-181b in angiotensin II–infused Apoe^−/− and Ldlr^−/− mice attenuated aneurysm formation and progression within the ascending, thoracic, and abdominal aorta. Moreover, miR-181b inhibition greatly increased elastin and collagen expression, promoting a fibrotic response and subsequent stabilization of existing plaques and aneurysms. We determined that miR-181b negatively regulates macrophage tissue inhibitor of metalloproteinase-3 expression and vascular smooth muscle cell elastin production, both important factors in maintaining atherosclerotic plaque and aneurysm stability. Validation studies in Timp3^−/− mice confirmed that the beneficial effects afforded by miR-181b inhibition are largely tissue inhibitor of metalloproteinase-3 dependent, while also revealing an additional protective effect through elevating elastin synthesis.

Conclusions:

Our findings suggest that the management of miR-181b and its target genes provides therapeutic potential for limiting the progression of atherosclerosis and aneurysms and protecting them from rupture.