MiR-181b Antagonizes Atherosclerotic Plaque Vulnerability Through Modulating Macrophage Polarization by Directly Targeting Notch1

Multiomics unveils extracellular vesicle-driven mechanisms of endothelial communication in human carotid atherosclerosis

Background: Carotid atherosclerosis is orchestrated by cell-cell communication that drives progression along a clinical continuum (asymptomatic to symptomatic). Extracellular vesicles (EVs) are cell-derived nanoparticles representing a new paradigm in cellular communication. Little is known about their biological cargo, cellular origin/destination, and functional roles in human atherosclerotic plaque. Methods: EVs were enriched via size exclusion chromatography from human carotid endarterectomy samples dissected into paired plaque and marginal zones (symptomatic n=16, asymptomatic n=13). EV cargos were assessed via whole transcriptome miRNA sequencing and mass spectrometry-based proteomics. EV multi-omics were integrated with bulk and single cell RNA-sequencing (scRNA-seq) datasets to predict EV cellular origin and ligand-receptor interactions, and multi-modal biological network integration of EV-cargo was completed. EV functional impact was assessed with endothelial angiogenesis assays. Results: Carotid plaques contained more EVs than adjacent marginal zones, with differential enrichment for EV-miRNAs and EV-proteins in key atherogenic pathways. EV cellular origin analysis suggested that tissue EV signatures originated from endothelial cells (EC), smooth muscle cells (SMC), and immune cells. Integrated tissue vesiculomics and scRNA-seq indicated complex EV-vascular cell communication that changed with disease progression and plaque vulnerability (i.e., symptomatic disease). Plaques from symptomatic patients, but not asymptomatic patients, were characterized by increased involvement of endothelial pathways and more complex ligand-receptor interactions, relative to their marginal zones. Plaque-EVs were predicted to mediate communication with ECs. Pathway enrichment analysis delineated an endothelial signature with roles in angiogenesis and neovascularization - well-known indices of plaque instability. This was validated functionally, wherein human carotid symptomatic plaque EVs induced sprouting angiogenesis in comparison to their matched marginal zones. Conclusion: Our findings indicate that EVs may drive dynamic changes in plaques through EV- vascular cell communication and effector functions that typify vulnerability to rupture, precipitating symptomatic disease. The discovery of endothelial-directed angiogenic processes mediated by EVs creates new therapeutic avenues for atherosclerosis.

MicroRNA-181 in cardiovascular disease: Emerging biomarkers and therapeutic targets

Cardiovascular disease (CVD) is the leading cause of death worldwide. MicroRNAs (MiRNAs) have attracted considerable attention for their roles in several cardiovascular disease states, including both the physiological and pathological processes. In this review, we will briefly describe microRNA-181 (miR-181) transcription and regulation and summarize recent findings on the roles of miR-181 family members as biomarkers or therapeutic targets in different cardiovascular-related conditions, including atherosclerosis, myocardial infarction, hypertension, and heart failure. Lessons learned from these studies may provide new theoretical foundations for CVD.

Macrophage-based therapeutic approaches for cardiovascular diseases

Despite the advances in treatment options, cardiovascular disease (CVDs) remains the leading cause of death over the world. Chronic inflammatory response and irreversible fibrosis are the main underlying pathophysiological causes of progression of CVDs. In recent decades, cardiac macrophages have been recognized as main regulatory players in the development of these complex pathophysiological conditions. Numerous approaches aimed at macrophages have been devised, leading to novel prospects for therapeutic interventions. Our review covers the advancements in macrophage-centric treatment plans for various pathologic conditions and examines the potential consequences and obstacles of employing macrophage-targeted techniques in cardiac diseases.

The potential role of miRNA in regulating macrophage polarization

Macrophage polarization is a dynamic process determining the outcome of various physiological and pathological situations through inducing pro-inflammatory responses or resolving inflammation via exerting anti-inflammatory effects. The miRNAs are epigenetic regulators of different biologic pathways that target transcription factors and signaling molecules to promote macrophage phenotype transition and regulate immune responses. Modulating the macrophage activation, differentiation, and polarization by miRNAs is crucial for immune responses in response to microenvironmental signals and under various physiological and pathological conditions. In term of clinical significance, regulating macrophage polarization via miRNAs could be utilized for inflammation control. Also, understanding the role of miRNAs in macrophage polarization can provide insights into diagnostic strategies associated with dysregulated miRNAs and for developing macrophage-centered therapeutic methods. In this case, targeting miRNAs to further regulate of macrophage polarization may become an efficient strategy for treating immune-associated disorders. The current review investigated and categorized various miRNAs directly or indirectly involved in macrophage polarization by targeting different transcription factors and signaling pathways. In addition, prospects for regulating macrophage polarization via miRNA as a therapeutic choice that could be implicated in various pathological conditions, including cancer or inflammation-mediated injuries, were discussed.

The role of miRNAs in Behçet's disease

The symptoms of Behçet's disease (BD), a multisystemic condition with autoimmune and inflammation as hallmarks, include arthritis, recurring oral and vaginal ulcers, skin rashes and lesions, and involvement of the nervous, gastrointestinal, and vascular systems. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), may be important regulators of inflammation and autoimmune disease. These ncRNAs are essential to the physiological and pathophysiological disease course, and miRNA in particular has received significant attention for its role and function in BD and its potential use as a diagnostic biomarker in recent years. Although promising as therapeutic targets, miRNAs must be studied further to fully comprehend how miRNAs in BD act biologically.

sFgl2-Treg Positive Feedback Pathway Protects against Atherosclerosis

Soluble fibrinogen-like protein 2 (sFgl2), a novel effector of regulatory T cells (Tregs), has been demonstrated to have potent immunosuppressive functions. Multiple studies indicate that Tregs could exert important atheroprotective effects, but their numbers gradually decrease during atherogenesis. The receptor of sFgl2 can be expressed on Treg precursor cells, while the role of sFgl2 on Treg differentiation and atherosclerosis progression remains unclear. Firstly, we detected that the sFgl2 was decreased in humans and mice with atherosclerotic diseases and was especially lower in their vulnerable plaques. Then, we used both Adeno-associated virus-sFgl2 (AAV-sFgl2)-injected ApoE^-/- mice, which is systemic overexpression of sFgl2, and sFgl2^TgApoE^-/- bone marrow cells (BMC)-transplanted ApoE^-/- mice, which is almost immune-system-specific overexpression of sFgl2, to explore the role of sFgl2 in atherosclerosis. Our experiment data showed that AAV-sFgl2 and BMT-sFgl2 could reduce atherosclerotic area and enhance plaque stability. Mechanistically, sFgl2 increases the abundance and immunosuppressive function of Tregs, which is partly mediated by binding to FcγRIIB receptors and phosphorylating Smad2/3. Collectively, sFgl2 has an atheroprotective effect that is mainly achieved by forming a positive feedback pathway with Treg. sFgl2 and Treg could synergistically protect against atherosclerosis.

Perfluorooctane sulfonate promotes atherosclerosis by modulating M1 polarization of macrophages through the NF-κB pathway

Perfluorooctane sulfonate (PFOS) is a widely used and distributed perfluorinated compounds and is reported to be harmful to cardiovascular health; however, the direct association between PFOS exposure and atherosclerosis and the underlying mechanisms remain unknown. Therefore, this study aimed to investigate the effects of PFOS exposure on the atherosclerosis progression and the underlying mechanisms. PFOS was administered through oral gavage to apolipoprotein E-deficient (ApoE^-/-) mice for 12 weeks. PFOS exposure significantly increased pulse wave velocity (PWV) and intima-media thickness (IMT), increased aortic plaque burden and vulnerability, and elevated serum lipid and inflammatory cytokine levels. PFOS promoted aortic and RAW264.7 M1 macrophage polarization, which increased the secretion of nitric oxide synthase (iNOS) and pro-inflammatory factors (tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6], and interleukin-1β [IL-1β]), and suppressed M2 macrophage polarization, which decreased the expression of CD206, arginine I (Arg-1), and interleukin-10 (IL-10). Moreover, PFOS activated nuclear factor-kappa B (NF-κB) in the aorta and macrophages. BAY11-7082 was used to inhibit NF-κB-alleviated M1 macrophage polarization and the inflammatory response induced by PFOS in RAW264.7 macrophages. Our results are the first to reveal the acceleratory effect of PFOS on the atherosclerosis progression in ApoE^-/- mice, which is associated with the NF-κB activation of macrophages to M1 polarization to induce inflammation.

Circular RNA circ_0002984 Promotes Cell Proliferation and Migration by Regulating miR-181b-5p/Vascular Endothelial Growth Factor Axis and PI3K-AKT Signaling Pathway in Oxidized Low-Density Lipoprotein-Treated Vascular Smooth Muscle Cells

ABSTRACT

RNAs (circRNAs) play critical roles in many diseases, including atherosclerosis (AS). However, the role and underlying mechanism of circ_0002984 in AS remain unclear. Vascular smooth muscle cells (VSMCs) treated with oxidized low-density lipoprotein (ox-LDL) were used as a AS cell model. Quantitative real-time polymerase chain reaction was conducted to detect the expression of circ_0002984, miR-181b-5p and vascular endothelial growth factor A (VEGFA). Cell proliferation was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide assay and 5-ethynyl-2'-deoxyuridine assays. Cell migration was assessed using wound healing assay and transwell assay. All protein levels were analyzed by western blot assay. The interaction between miR-181b-5p and circ_0002984 or VEGFA was confirmed by dual-luciferase reporter, RNA Immunoprecipitation, and RNA pull-down assays. Circ_0002984 and VEGFA were overexpressed, and miR-181b-5p was downregulated in serum of AS patients and ox-LDL-stimulated VSMCs. Circ_0002984 silencing inhibited ox-LDL-induced proliferation and migration in VSMCs. MiR-181b-5p was a target of circ_0002984, and miR-181b-5p inhibition counteracted the suppressing effects of circ_0002984 downregulation on proliferation and migration in ox-LDL-stimulated VSMCs. Additionally, VEGFA was a downstream target of miR-181b-5p and VEGFA upregulation abolished the suppressive influence of miR-181b-5p on proliferation and migration in ox-LDL-exposed VSMCs. Furthermore, circ_0002984 depletion blocked phosphatidylinositol 3 kinase-AKT signaling pathway by regulating miR-181b-5p and VEGFA. Circ_0002984 downregulation suppressed cell proliferation and migration by regulating miR-181b-5p/VEGFA axis and phosphatidylinositol 3 kinase-AKT pathway in ox-LDL-stimulated VEGFA, providing a new mechanism for AS pathogenesis.

Role of miR-181b/Notch1 Axis in circ_TNPO1 Promotion of Proliferation and Migration of Atherosclerotic Vascular Smooth Muscle Cells

Background

The role and expression level change in circ_TNPO1 (hsa_circ_0072951) in atherosclerosis (AS) and VSMC dysfunction remain unknown. In this study, we try to explore the effects of circ_TNPO1 on oxidized low-density lipoprotein (ox-LDL)-induced human vascular smooth muscle cell (VSMC) excessive proliferation and migration, and the potential molecular mechanism.

Methods

Quantitative real-time polymerase chain reaction (RT-qPCR) and western blot experiment were used to detect the serum samples from AS patients and healthy controls. CCK-8, Transwell, and the dual-luciferase reporter gene assay were used to detect the cell biology.

Results

In human AS serum and ox-LDL-induced VSMCs, circ_TNPO1 was increased, whereas miR-181b was decreased. Silencing circ_TNPO1 inhibited proliferation and migration activity and reduced protein expression of PCNA, Ki-67, MMP2, and E-cadherin and promoted N-cadherin protein expression in ox-LDL induced VSMCs. Remarkably, miR-181b knockdown or Notch1 overexpression could efficiently offset the proliferation and migration inhibiting effect of circ_TNPO1 knockdown in ox-LDL-induced VSMCs. Furthermore, a molecular mechanism study pointed out that circ_TNPO1 and Notch1 are direct-acting targets of miR-181b.

Conclusions

In conclusion, our study indicated that circ_TNPO1 promotes the proliferation and migration progression of VSMCs in atherosclerosis through the miR-181b/Notch1 axis.

MicroRNA-136-5p protects cardiomyocytes from coronary microembolization through the inhibition of pyroptosis

This study investigated how miR-136-5p partially affected cardiomyocyte pyroptosis in rats with coronary microembolization (CME). The cardiac function and structure of rats with CME were evaluated using echocardiography, hematoxylin and eosin staining, Masson staining, and troponin I level. Pyroptosis was induced by lipopolysaccharide (LPS) in isolated rat cardiomyocytes and evaluated by the expression of caspase-1, NOD-like receptor family pyrin domain-containing 3, interleukin-1β, and gasdermin D-N. After cell transfection, the expression of Ataxin-1 like (ATXN1L), pyrin domain-containing 1 (PYDC1), and pyroptosis-related proteins was assessed. Dual-luciferase reporter and immunoprecipitation assays were used to verify the relationships among miR-136-5p, ATXN1L, and capicua (CIC). MiR-136-5p was under-expressed, whereas ATXN1L was overexpressed in rats with CME and in LPS-treated primary cardiomyocytes. MiR-136-5p targeted ATXN1L, and ATXN1L bound to CIC to suppress PYDC1 expression. MiR-136-5p overexpression suppressed pyroptosis by inhibiting the binding of ATXN1L with CIC and promoting PYDC1 expression, which was reversed by simultaneous elevation of ATXN1L. In conclusion, miR-136-5p suppressed pyroptosis by upregulating PYDC1 via ATXN1L/CIC axis, thereby attenuating cardiac damage caused by CME.

A novel delivery nanobiotechnology: engineered miR-181b exosomes improved osteointegration by regulating macrophage polarization

Background

Many patients suffer from implant loosening after the implantation of titanium alloy caused by immune response to the foreign bodies and this could inhibit the following osteogenesis, which could possibly give rise to aseptic loosening and poor osteointegration while there is currently no appropriate solution in clinical practice. Exosome (Exo) carrying miRNA has been proven to be a suitable nanocarrier for solving this problem. In this study, we explored whether exosomes overexpressing miR-181b (Exo-181b) could exert beneficial effect on promoting M2 macrophage polarization, thus inhibiting inflammation as well as promoting osteogenesis and elaborated the underlying mechanism in vitro. Furthermore, we aimed to find whether Exo-181b could enhance osteointegration.

Results

In vitro, we firstly verified that Exo-181b significantly enhanced M2 polarization and inhibited inflammation by suppressing PRKCD and activating p-AKT. Then, in vivo, we verified that Exo-181b enhanced M2 polarization, reduced the inflammatory response and enhanced osteointegration. Also, we verified that the enhanced M2 polarization could indirectly promote the migration and osteogenic differentiation by secreting VEGF and BMP-2 in vitro.

Conclusions

Exo-181b could suppress inflammatory response by promoting M2 polarization via activating PRKCD/AKT signaling pathway, which further promoting osteogenesis in vitro and promote osteointegration in vivo.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01015-y.

Adding a "Notch" to Cardiovascular Disease Therapeutics: A MicroRNA-Based Approach

Dysregulation of the Notch pathway is implicated in the pathophysiology of cardiovascular diseases (CVDs), but, as of today, therapies based on the re-establishing the physiological levels of Notch in the heart and vessels are not available. A possible reason is the context-dependent role of Notch in the cardiovascular system, which would require a finely tuned, cell-specific approach. MicroRNAs (miRNAs) are short functional endogenous, non-coding RNA sequences able to regulate gene expression at post-transcriptional levels influencing most, if not all, biological processes. Dysregulation of miRNAs expression is implicated in the molecular mechanisms underlying many CVDs. Notch is regulated and regulates a large number of miRNAs expressed in the cardiovascular system and, thus, targeting these miRNAs could represent an avenue to be explored to target Notch for CVDs. In this Review, we provide an overview of both established and potential, based on evidence in other pathologies, crosstalks between miRNAs and Notch in cellular processes underlying atherosclerosis, myocardial ischemia, heart failure, calcification of aortic valve, and arrhythmias. We also discuss the potential advantages, as well as the challenges, of using miRNAs for a Notch-based approach for the diagnosis and treatment of the most common CVDs.

Therapies Targeted at Non-Coding RNAs in Prevention and Limitation of Myocardial Infarction and Subsequent Cardiac Remodeling-Current Experience and Perspectives

Myocardial infarction is one of the major causes of mortality worldwide and is a main cause of heart failure. This disease appears as a final point of atherosclerotic plaque progression, destabilization, and rupture. As a consequence of cardiomyocytes death during the infarction, the heart undergoes unfavorable cardiac remodeling, which results in its failure. Therefore, therapies aimed to limit the processes of atherosclerotic plaque progression, cardiac damage during the infarction, and subsequent remodeling are urgently warranted. A hopeful therapeutic option for the future medicine is targeting and regulating non-coding RNA (ncRNA), like microRNA, circular RNA (circRNA), or long non-coding RNA (lncRNA). In this review, the approaches targeted at ncRNAs participating in the aforementioned pathophysiological processes involved in myocardial infarction and their outcomes in preclinical studies have been concisely presented.

Different Approaches in Therapy Aiming to Stabilize an Unstable Atherosclerotic Plaque

Atherosclerotic plaque vulnerability is a vital clinical problem as vulnerable plaques tend to rupture, which results in atherosclerosis complications—myocardial infarctions and subsequent cardiovascular deaths. Therefore, methods aiming to stabilize such plaques are in great demand. In this brief review, the idea of atherosclerotic plaque stabilization and five main approaches—towards the regulation of metabolism, macrophages and cellular death, inflammation, reactive oxygen species, and extracellular matrix remodeling have been presented. Moreover, apart from classical approaches (targeted at the general mechanisms of plaque destabilization), there are also alternative approaches targeted either at certain plaques which have just become vulnerable or targeted at the minimization of the consequences of atherosclerotic plaque erosion or rupture. These alternative approaches have also been briefly mentioned in this review.

MicroRNA-125a-5p modulates macrophage polarization by targeting E26 transformation-specific variant 6 gene during orthodontic tooth movement

OBJECTIVE

The aim of this study was to investigate the role of microRNA-125a-5p (miR-125a-5p) in macrophages during orthodontic tooth movement (OTM).

DESIGN

Periodontal ligament tissues were collected from patients underwent OTM. Periodontal ligament cells were isolated from periodontal ligament tissues. Periodontal ligament stem cells were isolated from normal human impacted third molars. The miR-125-5p levels were measured by real-time quantitative polymerase chain reaction. The impact of miR-125-5p on macrophage polarization was tested by alizarin red staining assay. The effects of miR-125-5p and E26 transformation-specific variant 6 gene (ETV6) on M1/M2 macrophages phenotype markers were determined by real-time quantitative polymerase chain reaction, western blot, and flow cytometry analyses. The interaction between miR-125-5p and ETV6 was verified using luciferase reporter and RNA immunoprecipitation assays.

RESULTS

Periodontal miR-125a-5p was upregulated under the force. Macrophage polarization facilitated osteogenesis by cocultured system. Moreover, miR-125a-5p was upregulated in macrophages polarized with M2 conditions. MiR-125a-5p downregulation promoted the expression of M1 phenotype markers, while suppressed the expression of M2 markers. Mechanistically, ETV6 was confirmed to be a target of miR-125a-5p. ETV6 overexpression increased the expression of M1 polarized markers, while decreased the expression of M2 polarized markers. Furthermore, ETV6 knockdown reversed the effects of miR-125a-5p inhibitor on both M1 macrophages and M2 macrophages.

CONCLUSIONS

Overall, miR-125a-5p facilitates bone healing by targeting ETV6 to promote macrophage M2 polarization.

Search for Reliable Circulating Biomarkers to Predict Carotid Plaque Vulnerability

Atherosclerosis is responsible for 20% of ischemic strokes, and the plaques from the internal carotid artery the most frequently involved. Lipoproteins play a key role in carotid atherosclerosis since lipid accumulation contributes to plaque progression and chronic inflammation, both factors leading to plaque vulnerability. Carotid revascularization to prevent future vascular events is reasonable in some patients with high-grade carotid stenosis. However, the degree of stenosis alone is not sufficient to decide upon the best clinical management in some situations. In this context, it is essential to further characterize plaque vulnerability, according to specific characteristics (lipid-rich core, fibrous cap thinning, intraplaque hemorrhage). Although these features can be partly detected by imaging techniques, identifying carotid plaque vulnerability is still challenging. Therefore, the study of circulating biomarkers could provide adjunctive criteria to predict the risk of atherothrombotic stroke. In this regard, several molecules have been found altered, but reliable biomarkers have not been clearly established yet. The current review discusses the concept of vulnerable carotid plaque, and collects existing information about putative circulating biomarkers, being particularly focused on lipid-related and inflammatory molecules.

Long non-coding RNA HCG18 promotes M1 macrophage polarization through regulating the miR-146a/TRAF6 axis, facilitating the progression of diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is one of the most important complications in diabetes mellitus (DM), which has been reported to be modulated by long non-coding RNAs (lncRNAs). The purpose of the current study is to explore the regulatory mechanism of lncRNA HCG18 on DPN in vitro. The expression of lncRNA HCG18, miR-146a, TRAF6, CD11c, and iNOS was detected by qRT-PCR. Through Enzyme-linked immunosorbent assay, the levels of inflammatory factors (TNF-α, IL-1β, and IL-6) were determined. M1 macrophage polarization was measured by flow cytometry analysis. The interactions between miR-146a and HCG18/TRAF6 were predicted by Starbase/Targetscan software and verified by the dual luciferase reporter assay. Western blot assay was performed to determine the protein expression of TRAF6. LncRNA HCG18 was highly expressed in DPN model and HG-induced macrophages. The levels of inflammatory factors (TNF-α, IL-1β, and IL-6) were elevated in DPN model. The expression of M1 markers (CD11c and iNOS) was visibly up-regulated in DPN model and was positively correlated with HCG18 expression. LncRNA HCG18 facilitated M1 macrophage polarization. In addition, miR-146a was identified as a target of lncRNA HCG18. Overexpression of miR-146a reversed the promoting effect of HCG18 on M1 macrophage polarization. Simultaneously, TRAF6 was a target gene of miR-146a TRAF6 expression was positively modulated by HCG18 and was negatively modulated by miR-146a. Down-regulation of TRAF6 reversed the promoting effect of HCG18 on M1 macrophage polarization. LncRNA HCG18 promotes M1 macrophage polarization via regulating the miR-146a/TRAF6 axis, facilitating the progression of DPN. This study provides a possible therapeutic strategy for DPN.

The carotid plaque as paradigmatic case of site-specific acceleration of aging process: The microRNAs and the inflammaging contribution

Atherosclerosis is considered a chronic inflammatory disease of arteries associated with the aging process. Many risk factors have been identified and they are mainly related to life-styles, gene-environment interactions and socioeconomic status. Carotid and coronary artery diseases are the two major atherosclerotic conditions, being the primary cause of stroke and heart attack, respectively. Nevertheless, carotid plaque assumes particular aspects not only for the specific molecular mechanisms, but also for the types of atheroma which may be associated with a better or a worst prognosis. The identification of circulating blood biomarkers able to distinguish carotid plaque types (stable or vulnerable) is a crucial step for the improvement of adequate therapeutic approaches avoiding or delaying endarterectomy in the oldest old individuals (> 80 years), a population predicted to growth in the next years. The review highlights the most recent knowledge on carotid plaque molecular mechanisms, focusing on microRNAs (miRs), as a site-specific accelerated aging within the conceptual framework of Geroscience for new affordable therapies.

MicroRNAs as sentinels and protagonists of carotid artery thromboembolism

Stroke is the leading cause of serious disability in the world and a large number of ischemic strokes are due to thromboembolism from unstable carotid artery atherosclerotic plaque. As it is difficult to predict plaque rupture and surgical treatment of asymptomatic disease carries a risk of stroke, carotid disease continues to present major challenges with regard to clinical decision-making and revascularization. There is therefore an imminent need to better understand the molecular mechanisms governing plaque instability and rupture, as this would allow for the development of biomarkers to identify at-risk asymptomatic carotid plaque prior to disease progression and stroke. Further, it would aid in creation of therapeutics to stabilize carotid plaque. MicroRNAs (miRNAs) have been implicated as key protagonists in various stages of atherosclerotic plaque initiation, development and rupture. Notably, they appear to play a crucial role in carotid artery thromboembolism. As the molecular pathways governing the role of miRNAs are being uncovered, we are learning that their involvement is complex, tissue- and stage-specific, and highly selective. Notably, miRNAs can be packaged and secreted in extracellular vesicles (EVs), where they participate in cell-cell communication. The measurement of EV-encapsulated miRNAs in the circulation may inform disease mechanisms occurring in the plaque itself, and therefore may serve as sentinels of unstable plaque as well as therapeutic targets.

Non-coding RNAs in cardiovascular cell biology and atherosclerosis

Atherosclerosis underlies the predominant number of cardiovascular diseases and remains a leading cause of morbidity and mortality worldwide. The development, progression and formation of clinically relevant atherosclerotic plaques involves the interaction of distinct and over-lapping mechanisms which dictate the roles and actions of multiple resident and recruited cell types including endothelial cells, vascular smooth muscle cells, and monocyte/macrophages. The discovery of non-coding RNAs (ncRNAs) including microRNAs, long non-coding RNAs, and circular RNAs, and their identification as key mechanistic regulators of mRNA and protein expression has piqued interest in their potential contribution to atherosclerosis. Accruing evidence has revealed ncRNAs regulate pivotal cellular and molecular processes during all stages of atherosclerosis including cell invasion, growth, and survival; cellular uptake and efflux of lipids, expression and release of pro- and anti-inflammatory intermediaries, and proteolytic balance. The expression profile of ncRNAs within atherosclerotic lesions and the circulation have been determined with the aim of identifying individual or clusters of ncRNAs which may be viable therapeutic targets alongside deployment as biomarkers of atherosclerotic plaque progression. Consequently, numerous in vivo studies have been convened to determine the effects of moderating the function or expression of select ncRNAs in well-characterized animal models of atherosclerosis. Together, clinicopathological findings and studies in animal models have elucidated the multifaceted and frequently divergent effects ncRNAs impose both directly and indirectly on the formation and progression of atherosclerosis. From these findings' potential novel therapeutic targets and strategies have been discovered which may pave the way for further translational studies and possibly taken forward for clinical application.

MiRNA-494 enhances M1 macrophage polarization via Nrdp1 in ICH mice model

Background

Ubiquitination-mediated M1/M2 macrophage polarization plays important roles in the pathogenesis of immune disease. However, the regulatory mechanism of ubiquitination during M1/M2 macrophage polarization following intracerebral hemorrhage (ICH) has not been well studied.

Methods

In the experiment, macrophages were administered with erythrocyte lysates, and then miR-494-, Nrdp1-, and M1/M2-related markers were analyzed. Brain inflammatory response, brain edema, and neurological functions of ICH mice were also assessed.

Results

We found that miR-494 levels increased while Nrdp1 levels decreased in macrophages after ICH. We also demonstrated that miR-494 inhibited Nrdp1 expression by directly binding its 3′-untranslated region. MiR-494 attenuated C/EBP-β activation and downstream proinflammatory factor production. Upregulation of Nrdp1 in macrophages significantly promoted M2 macrophage polarization via ubiquitinating and activating C/EBP-β. Moreover, the results indicated that miR-494 could enhance M1 macrophage polarization, promote brain edema, and impair neurological functions in ICH mice.

Conclusions

Taken together, our results demonstrated that Nrdp1 contributed to M1/M2 macrophage polarization and neuroinflammation via ubiquitination and activation of C/EBP-β in ICH. miR-494 may provide a promising therapeutic clue for ICH.

Interleukin 37 Suppresses M1 Macrophage Polarization Through Inhibition of the Notch1 and Nuclear Factor Kappa B Pathways

Macrophage-orchestrated chronic inflammation plays an important role in cardiovascular disease, including accelerating the development of calcific aortic valve disease (CAVD). M1 and M2 macrophage polarization imbalances can alter intensity of inflammatory responses. Recombinant human interleukin 37 (IL-37) could be involved in regulating immune cell function to attenuate inflammation. This study aimed to identify IL-37 specifically modulates M1 polarization and investigate the underlying mechanism. Compared with normal valves, there are more M1 macrophages accumulation and less IL-37 expression in calcific aortic valves, which may indicate a negative relationship between IL-37 and M1 polarization. THP-1 cells could differentiate into resting macrophages with phorbol-12-myristate-13-acetate (PMA) and then polarize into M1 macrophages following treatment with lipopolysaccharide (LPS) and interferon gamma (IFN-γ). In vitro, recombinant human IL-37 attenuated the expression of inducible nitric oxide synthase (iNOS), CD11c, IL-6 and monocyte chemoattractant protein 1 (MCP-1) in M1 but augmented the expression of CD206 and IL-10 in M2. The suppression of M1 polarization was associated with the inhibition of the activation of the nuclear factor kappa B (NF-κB) and Notch1 signaling pathways. These results demonstrated that IL-37 inhibits the macrophages polarizing into M1 type via the inhibition of the Notch1 and nuclear factor kappa B pathways. In summary, IL-37 could be a potential therapeutic candidate for progressive CAVD by modulating M1 polarization and its orchestrated inflammation.

Oleoylethanolamide stabilizes atherosclerotic plaque through regulating macrophage polarization via AMPK-PPARα pathway

BACKGROUND

Atherosclerotic plaque rupture is the major trigger of acute cardiovascular risk events, and manipulation of M1/M2 macrophage homeostasis is an effective strategy for regulating atherosclerotic plaque stability. This study was aimed to illuminate the effects of oleoylethanolamide (OEA) on macrophage polarization and plaque stability.

METHODS

Macrophages derived from THP-1 were treated with OEA followed by LPS/IFN-γ, and the markers of M1, M2 macrophages were monitored by western blot, real-time PCR and immunofluorescence staining. The effect of OEA on macrophage polarization in the arch of aortic arteries was tested by immunofluorescence staining and western blot, and the plaque stability was completed by Masson's trichrome and hematoxylin and eosin (HE) in apolipoprotein E (ApoE)^-/- mice.

RESULTS

OEA treatment enhanced the expression of two classic M2 macrophage markers, macrophage mannose receptor (CD206) and transforming growth factor (TGF-β), while the expression of iNOS (M1 macrophages) was decreased in THP-1-derived macrophages. Blocking of PPARα using siRNA and inhibition of AMP-activated protein kinase (AMPK) by its inhibitor compound C attenuated the OEA-induced expression of M2 macrophage markers. In addition, OEA significantly suppressed M1, promoted M2 macrophage polarization, increased collagen content and decreased necrotic core size in atherosclerotic plaques in ApoE^-/- mice, which were linked with the expression of PPARα.

CONCLUSIONS

OEA improved atherosclerotic plaque stability through regulating macrophage polarization via AMPK-PPARα pathway.

The Role of miRNAs in Immune Cell Development, Immune Cell Activation, and Tumor Immunity: With a Focus on Macrophages and Natural Killer Cells

The tumor microenvironment (TME) is the primary arena where tumor cells and the host immune system interact. Bidirectional communication between tumor cells and the associated stromal cell types within the TME influences disease initiation and progression, as well as tumor immunity. Macrophages and natural killer (NK) cells are crucial components of the stromal compartment and display either pro- or anti-tumor properties, depending on the expression of key regulators. MicroRNAs (miRNAs) are emerging as such regulators. They affect several immune cell functions closely related to tumor evasion of the immune system. This review discusses the role of miRNAs in the differentiation, maturation, and activation of immune cells as well as tumor immunity, focusing particularly on macrophages and NK cells.

MicroRNA-582-5p suppresses non-small cell lung cancer cells growth and invasion via downregulating NOTCH1

Non-small cell lung cancer (NSCLC) is the most common cancer worldwide. MicroRNAs have been shown to be correlated with biological processes of various tumors. In this study, we observed that the expression of miR-582-5p was lower in NSCLC tissues than that in para-carcinoma tissues. Ectopic expression of miR-582-5p significantly inhibited NCI-H358 cell proliferation and invasion. Knockdown of miR-582-5p showed the opposite results, with cell growth rate and the invasive capacity of PC-9 cells enhanced. Furthermore, we elucidated that NOTCH1 is a target of miR-582-5p and there is an inverse correlation between miR-582-5p and NOTCH1 expression in NSCLC tissues. Overexpression of NOTCH1 in miR-582-5p-overexpressing NCI-H358 cells could partially reverse the inhibition of cell proliferation and invasion by miR-582-5p. Thus, our research demonstrated that miR-582-5p suppresses NSCLC cell lines’ growth and invasion via targeting oncoprotein NOTCH1 and restoration of miR-582-5p might be feasible therapeutic strategy for NSCLC.

Notch Signaling Regulates Immune Responses in Atherosclerosis

Atherosclerosis is a chronic autoimmune inflammatory disease that can cause coronary artery disease, stroke, peripheral artery disease, depending on which arteries are affected. At the beginning of atherosclerosis plasma lipoproteins accumulate in the sub-endothelial space. In response, monocytes migrate from the circulation through the endothelium into the intima where they differentiate into macrophages. These early events trigger a complex immune response that eventually involves many cellular subtypes of both innate and adaptive immunity. The Notch signaling pathway is an evolutionary conserved cell signaling system that mediates cell-to-cell communication. Recent studies have revealed that Notch modulate atherosclerosis by controlling macrophages polarization into M1 or M2 subtypes. Furthermore, it is known that Notch signaling controls differentiation and activity of T-helper and cytotoxic T-cells in inflammatory diseases. In this review, we will discuss the role of Notch in modulating immunity in the context of atherosclerosis and whether targeting Notch may represent a therapeutic strategy.

TET1 Knockdown Inhibits Porphyromonas gingivalis LPS/IFN-γ-Induced M1 Macrophage Polarization through the NF-κB Pathway in THP-1 Cells

Tet-eleven translocation 1 (TET1) is a dioxygenase that plays an important role in decreasing the abundance of DNA methylation and changing the expression levels of specific genes related to inflammation. Porphyromonas gingivalis (Pg.) lipopolysaccharide (LPS) can induce periodontal diseases that present with severe bone loss and collagen fiber destruction accompanied by a high number of M1 macrophages. M1-polarized macrophages are pivotal immune cells that promote the progression of the periodontal inflammatory response, but the function of TET1 during M1 macrophage activation is still unknown. Our results showed that the mRNA and protein expression levels of TET1 decreased in THP-1 cells during M1 macrophage differentiation. TET1 knockdown resulted in a significant decrease in the production of proinflammatory markers such as IL-6, TNF-α, CCL2, and HLA-DR in Pg. LPS/IFN-γ- and Escherichia coli (E. coli) LPS/IFN-γ-induced M1 macrophages. Mechanistically, TET1 knockdown downregulated the activity of the NF-κB signaling pathway. After treatment with the NF-κB inhibitor BAY 11-7082, M1 marker expression showed no significant difference between the TET1 knockdown group and the control group. Taken together, these results suggest that TET1 depletion inhibited Pg. LPS/IFN-γ-induced M1 macrophage polarization through the NF-κB pathway in THP-1 cells.

miR-181a/b therapy in lung cancer: reality or myth?

Despite substantial progress in oncology, lung cancer remains the number one malignancy in terms of both incidence and mortality rates, and there thus remains an urgent need for new therapeutic alternatives. MicroRNA (miRNA) have an important role in cancer initiation and progression due to their capacity to interfere with transcriptional signaling and regulate key cellular processes. miR-181a and miR-181b (miR-181a/b), which are located on chromosomes 1 and 9, are pathologically expressed in the tumor tissue and plasma of patients diagnosed with lung cancer. The miR-181a/b regulatory mechanisms are sophisticated and are directly related to different target genes. In recent years, an ever-increasing number of studies have focused on the biological relevance of miR-181a/b in key cellular processes. In this paper, we aim to discuss the challenging experimental data related to miR-181a/b and their potential use for the development of new therapeutic approaches in lung cancer. We will further present the ongoing issues regarding the regulation of their multiple target genes, and their potential use as biomarkers and therapeutic targets in this deadly malignancy.

Association between MEG3/miR-181b polymorphisms and risk of ischemic stroke

BACKGROUND

Recent evidence suggests that long non-coding RNAs (lncRNAs) are key regulators in the pathological process of ischemic stroke (IS). Maternally expressed gene 3 (MEG3) was observed to be up-regulated in IS, acting as a competing endogenous RNA for miR-181b to regulate ischemic brain injury. The purpose of this study was to evaluate the association of tagSNPs in MEG3 (i.e., rs7158663 and rs4081134) and miR-181b rs322931 with IS risk.

METHODS

Genomic DNA was extracted from blood samples of 509 patients with IS and 668 healthy controls. Genotyping of MEG3 rs7158663, rs4081134, and miR-181b rs322931 was performed by TaqMan assay. The transcriptional activity was measured using the Dual-Luciferase Reporter Assay kit.

RESULTS

Single-site analysis revealed a significantly higher risk of IS being associated with miR-181b rs322931 CT and CT/TT genotypes (CT vs. CC: adjusted OR = 1.48, 95% CI: 1.13-1.95, P = 0.005; CT/TT vs. CC: adjusted OR = 1.52, 95% CI: 1.17-1.97, P = 0.002). Combined analyses revealed that combined genotypes (rs7158663 GG + rs322931 CT/TT and rs7158663 AG/AA + rs322931 CT/TT) increased IS risk compared to genotypes of rs7158663 GG + rs322931 CC. Stratification analyses showed that patients carrying miR-181b rs322931 CT/TT genotypes had higher levels of low-density lipoprotein cholesterol (LDL_C) (P = 0.01). Moreover, results from logistic regression analysis showed that rs322931 CT/TT genotypes were risk factors besides hypertension, total cholesterol, triglyceride, and LDL_C. Further dual-luciferase reporter assay showed that the rs322931 T allele had lower levels of luciferase activity than the rs322931 C allele.

CONCLUSION

These findings indicate that miR-181b rs322931 may singly or jointly contribute to the risk of IS.

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.

MicroRNA-23a-5p promotes atherosclerotic plaque progression and vulnerability by repressing ATP-binding cassette transporter A1/G1 in macrophages

Disruption of carotid vulnerable atherosclerotic plaque is responsible for acute ischemic stroke (AIS) and the early detection and intervention approach are greatly limited. Undertaking a microarray of microRNAs (miRNAs) in the plasma of AIS patients with carotid vulnerable plaques, miR-23a-5p was markedly elevated and was positively correlated with the plaque progression and vulnerability. Correspondingly, we found that miR-23a-5p expression was significantly increased in both plasma and macrophages from atherosclerosis mice. Bioinformatics analysis and in vitro knockdown experiments identified that ATP-binding cassette transporter A1/G1 as a novel target of miR-23a-5p. Luciferase reporter assays showed that miR-23a-5p repressed the 3' untranslated regions (UTR) activity of ABCA1/G1. Moreover, functional analyses demonstrated that transfection of miR-23a-5p inhibitor enhanced cholesterol efflux and decreased foam cell formation through upregulating ABCA1/G1 expression levels. Furthermore, long term in vivo systemically delivered miR-23a-5p antagomir significantly increased ABCA1/G1 expression in the aorta of ApoE^-/- mice. Importantly, the miR-23a-5p antagomir therapy significantly reduced atherosclerosis progression and promoted plaque stability. Our observations indicate that miR-23a-5p promotes macrophage-derived foam cell formation and might be a key regulator contributing to atherosclerotic plaque progression and vulnerability.

miR-181b inhibits chemoresistance in cisplatin-resistant H446 small cell lung cancer cells by targeting Bcl-2

INTRODUCTION

MicroRNAs (miRNAs) are a group of small non-coding RNAs that affect multiple aspects of tumor biology including chemo resistance. miR-181b has been reported to modulate multidrug resistance in non-small cell lung cancer cells. This study was undertaken to determine the role of miR-181b in chemo resistance of small cell lung cancer cells.

MATERIAL AND METHODS

This study was undertaken to determine the role of miR-181b in chemoresistance of small cell lung cancer cells with use of qRt-PCR, WB, bioinformatics analysis, and double luciferase reporter system.

RESULTS

Our data showed that miR-181b was significantly downregulated in cisplatin-resistant H446 small cell lung cancer cells, compared to parental cells, compared to parental cells. Ectopic expression of miR-181b inhibited cell proliferation and invasion in cisplatin-resistant H446 cells (p = 0.023). Moreover, overexpression of miR-181b increased the susceptibility of cisplatin-resistant H446 cells to cisplatin. Mechanistic investigations demonstrated that miR-181b inhibited B-cell lymphoma-2 (Bcl-2) expression by binding to the 3'-untranslated region. Overexpression of Bcl-2 reversed miR-181b-mediated chemo sensitization, which is accompanied by a reduced apoptotic response.

CONCLUSIONS

Taken together, this work demonstrated that miR-181b might have the ability to overcome chemo resistance of small cell lung cancer cells, and restoration of this miRNA may represent a potential therapeutic strategy for improving chemo sensitivity in small cell lung cancer.