Exosomes from nicotine-stimulated macrophages accelerate atherosclerosis through miR-21-3p/PTEN-mediated VSMC migration and proliferation

Extracellular Vesicles: Versatile Nanomediators, Potential Biomarkers and Therapeutic Agents in Atherosclerosis and COVID-19-Related Thrombosis

Cells convey information among one another. One instrument employed to transmit data and constituents to specific (target) cells is extracellular vesicles (EVs). They originate from a variety of cells (endothelial, immune cells, platelets, mesenchymal stromal cells, etc.), and consequently, their surface characteristics and cargo vary according to the paternal cell. The cargo could be DNA, mRNA, microRNA, receptors, metabolites, cytoplasmic proteins, or pathological molecules, as a function of which EVs exert different effects upon endocytosis in recipient cells. Recently, EVs have become important participants in a variety of pathologies, including atherogenesis and coronavirus disease 2019 (COVID-19)-associated thrombosis. Herein, we summarize recent advances and some of our own results on the role of EVs in atherosclerotic cardiovascular diseases, and discuss their potential to function as signaling mediators, biomarkers and therapeutic agents. Since COVID-19 patients have a high rate of thrombotic events, a special section of the review is dedicated to the mechanism of thrombosis and the possible therapeutic potential of EVs in COVID-19-related thrombosis. Yet, EV mechanisms and their role in the transfer of information between cells in normal and pathological conditions remain to be explored.

Therapeutic Exosomes in Prognosis and Developments of Coronary Artery Disease

Exosomes, with an diameter of 30~150 nm, could be released from almost all types of cells, which contain diverse effective constituent, such as RNAs, proteins, lipids, and so on. In recent years, exosomes have been verified to play an important role in mechanism, diagnosis, treatment, and prognosis of cardiovascular disease, especially coronary artery disease (CAD). Moreover, it has also been shown that exosomes derived from different cell types have various biological functions based on the cell stimulation and microenvironment. However, therapeutic exosomes are currently far away from clinical translation, despite it is full of hope. In this review, we summarize an update of the recent studies and systematic knowledge of therapeutic exosomes in atherosclerosis, myocardial infarction, and in-stent restenosis, which might provide a novel insight into the treatment of CAD and promote the potential clinical application of therapeutic exosomes.

LncRNA Landscape of Coronary Atherosclerosis Reveals Differentially Expressed LncRNAs in Proliferation and Migration of Coronary Artery Smooth Muscle Cells

We aimed to investigate differentially expressed long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) in atherosclerosis and validate the expression of lncRNAs and co-expressed target genes in proliferation and migration models of human coronary artery smooth muscle cells (HCASMCs). Ten coronary artery specimens from a subject who died from a heart attack were employed. The pathological analysis was analyzed by hematoxylin and eosin (H&E) staining, and the lncRNAs and mRNAs were identified by RNA sequencing. Bioinformatic analyses were performed to predict possible mechanisms. The proliferation and migration of HCASMCs were induced with oxidized low-density lipoprotein (ox-LDL). Differentially expressed lncRNAs and mRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR). In this study, 68 lncRNAs and 222 mRNAs were identified differentially expressed in atherosclerosis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that the Fanconi anemia pathway may be involved in atherosclerosis. GON4L was found to be the co-localized target gene of LNC_000439, and 14 genes had high correlations with the expression of seven lncRNAs. In addition, nine lncRNA–miRNA–mRNA networks were constructed, and 53 co-expressed gene modules were detected with weighted gene co-expression network analysis (WGCNA). LNC_000684, LNC_001046, LNC_001333, LNC_001538, and LNC_002115 were downregulated, while LNC_002936 was upregulated in proliferation and migration models of HCASMCs. In total, six co-expressed mRNAs were upregulated in HCASMCs. This study suggests that the differentially expressed lncRNAs identified by RNA sequencing and validated in smooth muscle cells may be a target for regulating HCASMC proliferation and migration in atherosclerosis, which will provide a new diagnostic basis and therapeutic target for the treatment of cardiovascular diseases.

miR-141-3p Reduces Cell Migration and Proliferation in an In Vitro Modelof Atherosclerosis by Targeting Wnt5a

BACKGROUND

Atherosclerosis (AS) is a type of chronic vascular disease that is also a leading cause of numerous cardiovascular diseases in humans. The biomolecules responsible for the roles of microRNA (miR)-141-3p during AS development are less understood.

METHODS

The relation between Wnt5a and miR-141-3p was predicted using bioinformatics software TargetScan 7.1, and confirmed via dual luciferase reporter assay. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunoblotting were conducted for examining miR-141-3p and Wingless and Int-1 (Wnt)5a expression levels. Additionally, transwell migration and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were conducted for analyzing cell migration and proliferation, respectively.

RESULTS

miR-141-3p was decreased in oxidized low-density lipoprotein (ox-LDL)-treated human vascular smooth muscle cells (VSMCs). Pretreatment with miR-141-3p mimic inhibited cell migration and proliferation in ox-LDL-induced VSMCs. Wnt5a was verified to act as the target of miR-141-3p in VSMCs. pcDNA3-Wnt5a partially reversed the effects of miR-141-3p mimic in ox-LDL-stimulated VSMCs.

CONCLUSION

miR-141-3p mimic decreased the damage in an AS model by targeting Wnt5a, thereby presenting a novel potential therapeutic target for treating AS.

Nicotine: Regulatory roles and mechanisms in atherosclerosis progression

Smoking is an independent risk factor for atherosclerosis. The smoke produced by tobacco burning contains more than 7000 chemicals, among which nicotine is closely related to the occurrence and development of atherosclerosis. Nicotine, a selective cholinergic agonist, accelerates the formation of atherosclerosis by stimulating nicotinic acetylcholine receptors (nAChRs) located in neuronal and non-neuronal tissues. This review introduces the pathogenesis of atherosclerosis and the mechanisms involving nicotine and its receptors. Herein, we focus on the various roles of nicotine in atherosclerosis, such as upregulation of growth factors, inflammation, and the dysfunction of endothelial cells, vascular smooth muscle cells (VSMC) as well as macrophages. In addition, nicotine can stimulate the generation of reactive oxygen species, cause abnormal lipid metabolism, and activate immune cells leading to the onset and progression of atherosclerosis. Exosomes, are currently a research hotspot, due to their important connections with macrophages and the VSMC, and may represent a novel application into future preventive treatment to promote the prevention of smoking-related atherosclerosis. In this review, we will elaborate on the regulatory mechanism of nicotine on atherosclerosis, as well as the effects of interference with nicotine receptors and the use of exosomes to prevent atherosclerosis development.

Exosomes in atherosclerosis: performers, bystanders, biomarkers, and therapeutic targets

Exosomes are nanosized lipid vesicles originating from the endosomal system that carry many macromolecules from their parental cells and play important roles in intercellular communication. The functions and underlying mechanisms of exosomes in atherosclerosis have recently been intensively studied. In this review, we briefly introduce exosome biology and then focus on advances in the roles of exosomes in atherosclerosis, specifically exosomal changes associated with atherosclerosis, their cellular origins and potential functional cargos, and their detailed impacts on recipient cells. We also discuss the potential of exosomes as biomarkers and drug carriers for managing atherosclerosis.

The Potential of Exosomal RNAs in Atherosclerosis Diagnosis and Therapy

Atherosclerosis is an inflammatory disease that can lead to cardiovascular disorders and stroke. In the atherosclerosis microenvironment, exosomes secreted from various cells, especially macrophage-derived exosomes, play an important role in cell–cell communication and cellular biological functions. In this article, we review previous studies on exosomal RNAs and discuss their potential value in atherosclerosis diagnosis and therapy. Based on our research, we concluded that macrophage exosomes have potential value in atherosclerosis diagnosis and therapy. However, there is a need for future studies to further investigate methods of exosome isolation and targeting.

Exosomes and Exosomal MicroRNAs in Age-Associated Stroke

Aging has been considered to be the most important non-modifiable risk factor for stroke and death. Changes in circulation factors in the systemic environment, cellular senescence and artery hypertension during human ageing have been investigated. Exosomes are nanosize membrane vesicles that can regulate target cell functions via delivering their carried bioactive molecules (e.g. protein, mRNA, and microRNAs). In the central nervous system, exosomes and exosomal microRNAs play a critical role in regulating neurovascular function, and are implicated in the initiation and progression of stroke. MicroRNAs are small non-coding RNAs that have been reported to play critical roles in various biological processes. Recently, evidence has shown that microRNAs are packaged into exosomes and can be secreted into the systemic and tissue environment. Circulating microRNAs participate in cellular senescence and contribute to age-associated stroke. Here, we provide an overview of current knowledge on exosomes and their carried microRNAs in the regulation of cellular and organismal ageing processes, demonstrating the potential role of exosomes and their carried microRNAs in age-associated stroke.

Recent Advances in Epigenetics of Macrovascular Complications in Diabetes Mellitus

Diabetes mellitus is a metabolic and endocrine disorder characterised by hyperglycaemia. Type 2 diabetes mellitus accounts for >90% of people with diabetes. Disorders of blood glucose metabolism and a series of adverse reactions triggered by hyperglycaemia-such as oxidative stress and inflammation-are conducive to the occurrence of diabetic macrovascular complications, which pose severe challenges to the quality of life and life expectancy of people with diabetes. In recent years, epigenetics has attracted more and more researchers' attention as they explore the causes and treatment of diabetes. Epigenetics refers to the regulation of gene expression without changes in gene content. Research focusses on DNA methylation, histone post-translational modification and non-coding RNA. A series of studies have shown that epigenetic regulation accelerates the development of atherosclerosis by interfering with the physiological activities of macrophages, endothelial cells and smooth muscle cells, such as inflammation, lipid deposition and apoptosis. Therefore, it is particularly important to explore new epigenetic discoveries to reduce the severity and harmfulness of diabetes. This study reviewed recent advances in epigenetics in the pathogenesis of diabetes mellitus and its macrovascular complications.

The Role of Exosomes and Exosomal MicroRNA in Cardiovascular Disease

Exosomes are small vesicles (30–150 nm in diameter) enclosed by a lipid membrane bilayer, secreted by most cells in the body. They carry various molecules, including proteins, lipids, mRNA, and other RNA species, such as long non-coding RNA, circular RNA, and microRNA (miRNA). miRNAs are the most numerous cargo molecules in the exosome. They are endogenous non-coding RNA molecules, approximately 19–22-nt-long, and important regulators of protein biosynthesis. Exosomes can be taken up by neighboring or distant cells, where they play a role in post-transcriptional regulation of gene expression by targeting mRNA. Exosomal miRNAs have diverse functions, such as participation in inflammatory reactions, cell migration, proliferation, apoptosis, autophagy, and epithelial–mesenchymal transition. There is increasing evidence that exosomal miRNAs play an important role in cardiovascular health. Exosomal miRNAs are widely involved in the occurrence and development of cardiovascular diseases, such as atherosclerosis, acute coronary syndrome, heart failure (HF), myocardial ischemia reperfusion injury, and pulmonary hypertension. In this review, we present a systematic overview of the research progress into the role of exosomal miRNAs in cardiovascular diseases, and present new ideas for the diagnosis and treatment of cardiovascular diseases.

Power and promise of exosomes as clinical biomarkers and therapeutic vectors for liquid biopsy and cancer control

Exosomes, microvesicles derived from the nuclear endosome and plasma membrane, can be released into the extracellular environment to act as mediators between the cell membrane and cytoplasmic proteins, lipids, or RNA. Exosomes are considered effective carriers of intercellular signals in prokaryotes and eukaryotes, because of their ability to efficiently transfer proteins, lipids, and nucleic acids between cellular compartments. Since the 2007 discovery that exosomes carry bioactive substances, exosomes have been intensively researched. In various physiological and pathological processes, exosomes play important biological roles by specifically combining with receptor cells and transmitting information. Their stable biological characteristics, diversity of contents, non-invasiveness path for introducing signaling molecules, and ability for rapid detection make exosomes a promising clinical diagnostic marker for potentially many pathological conditions, including cancers. Exosomes are not only considered biomarkers and prognostic disease factors, but also have potential as gene carriers and drug delivery vectors, and have important clinical significance and application potential in the fields of cancer diagnosis, prognosis, and treatment.

The Role of Exosomal Non-Coding RNAs in Coronary Artery Disease

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide. Atherosclerosis (AS) is a major cause of CVD. Oxidative stress, endothelial dysfunction, and inflammation are key factors involved in the development and progression of AS. Exosomes are nano-sized vesicles secreted into the extracellular space by most types of cells, and are ideal substances for the transmission and integration of signals between cells. Cells can selectively encapsulate biologically active substances, such as lipids, proteins and RNA in exosomes and act through paracrine mechanisms. Non-coding RNAs (ncRNAs) are important for communication between cells. They can reach the recipient cells through exosomes, causing phenotypic changes and playing a molecular regulatory role in cell function. Elucidating their molecular mechanisms can help identify therapeutic targets or strategies for CVD. Coronary artery disease (CAD) is the most important disease in CVD. Here, we review the role and the regulatory mechanism of exosomal ncRNAs in the pathophysiology of CAD, as well as the potential contribution of exosomal ncRNA to diagnosis and treatment of CAD.

The role of extracellular vesicles in neointima formation post vascular injury

Pathological neointimal growth can develop in patients as a result of vascular injury following percutaneous coronary intervention and coronary artery bypass grafting using autologous saphenous vein, leading to arterial or vein graft occlusion. Neointima formation driven by intimal hyperplasia occurs as a result of a complex interplay between molecular and cellular processes involving different cell types including endothelial cells, vascular smooth muscle cells and various inflammatory cells. Therefore, understanding the intercellular communication mechanisms underlying this process remains of fundamental importance in order to develop therapeutic strategies to preserve endothelial integrity and vascular health post coronary interventions. Extracellular vesicles (EVs), including microvesicles and exosomes, are membrane-bound particles secreted by cells which mediate intercellular signalling in physiological and pathophysiological states, however their role in neointima formation is not fully understood. The purification and characterization techniques currently used in the field are associated with many limitations which significantly hinder the ability to comprehensively study the role of specific EV types and make direct functional comparisons between EV subpopulations. In this review, the current knowledge focusing on EV signalling in neointima formation post vascular injury is discussed.

Targeting HDAC6 attenuates nicotine-induced macrophage pyroptosis via NF-κB/NLRP3 pathway

BACKGROUND AND AIMS

During the development of atherosclerosis, nicotine activates macrophage inflammation. However, whether nicotine induces macrophage pyroptosis and the underlying mechanisms remain unclear. This study aimed to investigate the role of histone deacetylase 6 (HDAC6) in nicotine-induced macrophage pyroptosis.

METHODS

For the in vivo study, nicotine was administered to 8-week-old ApoE^-/- mice fed a high-fat diet (HFD) for 12 weeks. TUNEL/CD68 and Caspase-1/CD68 staining was used to assess macrophage pyroptosis in plaque. For the in vitro study, Western blotting, lactic dehydrogenase activity (LDH), coimmunoprecipitation, chromatin immunoprecipitation and immunofluorescence were used to evaluate pyroptosis and related signaling pathway in RAW264.7 cells.

RESULTS

A high-fat diet and nicotine upregulated macrophage pyroptosis in atherosclerotic lesions. Nicotine promoted pyroptosis in RAW264.7 cells, as evidenced by increased expression of cleaved Caspase1, NLRP3, IL-1β, IL-18, and elevated LDH release. Inhibition of HDAC6 suppressed nicotine-induced pyroptosis, which is partly mediated by p65 acetylation and NLRP3 transcription. Silencing p65 or NLRP3 resulted in decreased pyroptosis in RAW264.7 cells.

CONCLUSIONS

Nicotine induces macrophage pyroptosis in atherosclerosis through HDAC6/NF-κB/NLRP3 signaling pathway.

Stem cell-derived exosomes: Role in the pathogenesis and treatment of atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory vascular disease characterized by the accumulation of lipids and inflammatory debris in large arteries, high morbidity, and AS-related disease mortality. AS is a complex process, involving endothelial cell dysfunction and inflammation, smooth muscle cell proliferation, and macrophage activation. However, the currently available therapies for AS are not ideal, thus requiring development of novel treatment strategies. Exosomes are bi-lipid membranous extracellular containing multifarious cargo, such as proteins, lipids, micro ribonucleic acid (miRNAs), messenger RNAs, and long non-coding RNAs. Moreover, exosomes reportedly participate in various AS processes. Specifically, stem cell-derived exosomes can regulate the occurrence and development of AS, exhibiting the ability to overcome the limitations associated with AS treatment and stem cell therapy. In this paper, we review the pathological mechanism of AS and discuss the role of exosomes and stem cell-derived exosomes in AS progression. We conclude by suggesting new therapeutic strategies for treating AS with stem cell-derived exosomes in the hope of improving the clinical treatment of AS.

The Cell Type-Specific Functions of miR-21 in Cardiovascular Diseases

Cardiovascular diseases are one of the prime reasons for disability and death worldwide. Diseases and conditions, such as hypoxia, pressure overload, infection, and hyperglycemia, might initiate cardiac remodeling and dysfunction by inducing hypertrophy or apoptosis in cardiomyocytes and by promoting proliferation in cardiac fibroblasts. In the vascular system, injuries decrease the endothelial nitric oxide levels and affect the phenotype of vascular smooth muscle cells. Understanding the underlying mechanisms will be helpful for the development of a precise therapeutic approach. Various microRNAs are involved in mediating multiple pathological and physiological processes in the heart. A cardiac enriched microRNA, miR-21, which is essential for cardiac homeostasis, has been demonstrated to act as a cell–cell messenger with diverse functions. This review describes the cell type–specific functions of miR-21 in different cardiovascular diseases and its prospects in clinical therapy.

Exosomes in Cardiovascular Diseases

Exosomes are nano-sized biovesicles of endocytic origin physiologically released by nearly all cell types into surrounding body fluids. They carry cell-specific cargos of protein, lipids, and genetic materials and can be selectively taken up by neighboring or distant cells. Since the intrinsic properties of exosomes are strictly influenced by the state of the parental cell and by the cellular microenvironment, the analysis of exosome origin and content, and their cell-targeting specificity, make them attractive as possible diagnostic and prognostic biomarkers. While the possible role of exosomes as messengers and a regenerative tool in cardiovascular diseases (CVDs) is actively investigated, the evidence about their usefulness as biomarkers is still limited and incomplete. Further complications are due to the lack of consensus regarding the most appropriate approach for exosome isolation and characterization, both important issues for their effective clinical translation. As a consequence, in this review, we will discuss the few information currently accessible about the diagnostic/prognostic potential of exosomes in CVDs and on the methodologies available for exosome isolation, analysis, and characterization.

Roles of exosomal miRNA in vascular aging

Aging is a major risk factor for human diseases. As global average life expectancy has lengthened, delaying or reducing aging and age-related diseases has become an urgent issue for improving the quality of life. The vascular aging process represents an important link between aging and age-related diseases. Exosomes are small extracellular vesicles (EV) that can be secreted by almost all eukaryotic cells, and they deliver characteristic biological information about donor cells to regulate the cellular microenvironment, mediate signal transmission between neighboring or distant cells, and affect the expression of target genes in recipient cells. Many recent studies have shown that exosomal microribonucleic acids (miRNA) are involved in the regulation of vascular aging by participating in the physiological functions of vascular cells and the destruction and remodeling of the extracellular matrix (ECM). This review summarizes the regulatory functions of exosomal miRNA in vascular aging because they interact with the ECM, and participate in vascular cell senescence, and the regulation of senescence-related functions such as proliferation, migration, apoptosis, inflammation, and differentiation.

Macrophage-derived extracellular vesicles: diverse mediators of pathology and therapeutics in multiple diseases

Macrophages (Mφ) are primary innate immune cells that exhibit diverse functions in response to different pathogens or stimuli, and they are extensively involved in the pathology of various diseases. Extracellular vesicles (EVs) are small vesicles released by live cells. As vital messengers, macrophage-derived EVs (Mφ-EVs) can transfer multiple types of bioactive molecules from macrophages to recipient cells, modulating the biological function of recipient cells. In recent years, Mφ-EVs have emerged as vital mediators not only in the pathology of multiple diseases such as inflammatory diseases, fibrosis and cancers, but also as mediators of beneficial effects in immunoregulation, cancer therapy, infectious defense, and tissue repair. Although many investigations have been performed to explore the diverse functions of Mφ-EVs in disease pathology and intervention, few studies have comprehensively summarized their detailed biological roles as currently understood. In this review, we briefly introduced an overview of macrophage and EV biology, and primarily focusing on current findings and future perspectives with respect to the pathological and therapeutic effects of Mφ-EVs in various diseases.

Long noncoding RNA ZNF800 suppresses proliferation and migration of vascular smooth muscle cells by upregulating PTEN and inhibiting AKT/mTOR/HIF-1α signaling

BACKGROUND AND AIMS

Long noncoding RNAs (lncRNAs) have recently been implicated in many biological and disease processes, but the exact mechanism of their involvement in atherosclerosis is unclear. The aberrant proliferation and migration of vascular smooth muscle cells (VSMCs) is a major contributor to the development of atherosclerotic lesions. This study aimed to investigate the potential effects of lncRNA ZNF800, a previously uncharacterized lncRNA, on VSMC proliferation and migration.

METHODS

The expression of lncRNA ZNF800 in atherosclerotic plaque tissues was detected using reverse transcription-quantitative PCR (RT-qPCR), while the role and mechanism of lncRNA ZNF800 in proliferation and migration of VSMCs were investigated by CCK8 assay, transwell assay, scratch wound assay, RT-qPCR and Western blot.

RESULTS

We found that lncRNA ZNF800 was significantly more abundant in atherosclerotic plaque tissues, and substantially suppressed the proliferation and migration of VSMCs. LncRNA ZNF800 had no effect on phosphatase and tensin homolog deleted on chromosome 10 (PTEN) mRNA expression but dramatically increased the levels of PTEN protein. Enhanced lncRNA ZNF800 expression inhibited the activity of the AKT/mTOR/HIF-1α signaling pathway, downregulated the expression of vascular endothelial growth factor α (VEGF-α) and matrix metalloproteinase 1 (MMP1), and suppressed VSMC proliferation and migration. These inhibitory effects of lncRNA ZNF800 were abolished by knockdown of PTEN. The inhibitory effects of lncRNA ZNF800 on cell proliferation and migration and the expression of VEGF-α and MMP1 were exacerbated by HIF-1α knockdown in VSMCs.

CONCLUSIONS

These findings demonstrated that lncRNA ZNF800 suppressed VSMC proliferation and migration by interacting with PTEN through a mechanism involving AKT/mTOR/HIF-1α signaling. Therefore, it may play a key atheroprotective role and represent a potential therapeutic target for atherosclerosis-related diseases.

Role of Extracellular Vesicles in Substance Abuse and HIV-Related Neurological Pathologies

Extracellular vesicles (EVs) are a broad, heterogeneous class of membranous lipid-bilayer vesicles that facilitate intercellular communication throughout the body. As important carriers of various types of cargo, including proteins, lipids, DNA fragments, and a variety of small noncoding RNAs, including miRNAs, mRNAs, and siRNAs, EVs may play an important role in the development of addiction and other neurological pathologies, particularly those related to HIV. In this review, we summarize the findings of EV studies in the context of methamphetamine (METH), cocaine, nicotine, opioid, and alcohol use disorders, highlighting important EV cargoes that may contribute to addiction. Additionally, as HIV and substance abuse are often comorbid, we discuss the potential role of EVs in the intersection of substance abuse and HIV. Taken together, the studies presented in this comprehensive review shed light on the potential role of EVs in the exacerbation of substance use and HIV. As a subject of growing interest, EVs may continue to provide information about mechanisms and pathogenesis in substance use disorders and CNS pathologies, perhaps allowing for exploration into potential therapeutic options.

Overexpression of miR-29a-3p Suppresses Proliferation, Migration, and Invasion of Vascular Smooth Muscle Cells in Atherosclerosis via Targeting TNFRSF1A

Objective

Increasing evidence highlights the significance of microRNAs (miRNAs) in the progression of atherosclerosis (AS). Our aim was to probe out the role and regulatory mechanism of miR-29a-3p in AS.

Methods

An in vivo model of AS was conducted by high-fat diet ApoE^-/- mice. Oxidized low-density lipoprotein- (ox-LDL-) exposed vascular smooth muscle cells (VSMCs) were utilized as an in vitro of AS. Serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were detected. Hematoxylin and eosin (H&E) and Masson's staining was presented to investigate the pathological changes. miR-29a-3p and TNFRSF1A expression was detected by RT-qPCR. Proliferative, migrated, and invaded abilities of VSMCs were determined via a series of assays. The interaction between miR-29a-3p and TNFRSF1A was verified through luciferase reporter assay.

Results

Upregulated miR-29a-3p and downregulated TNFRSF1A were found both in vitro and in vivo models of AS. miR-29a-3p mimic distinctly decreased the serum levels of TC, TG, and LDL-C and increased serum HDL-C levels. Moreover, its overexpression could ameliorate plaque formation of AS mice. In ox-LDL-induced VSMCs, miR-29a-3p overexpression notably decreased cell proliferation, migration, and invasion, which was reversed by TNFRSF1A overexpression. Also, miR-29a-3p could directly target the 3'UTR of TNFRSF1A.

Conclusion

miR-29a-3p overexpression ameliorated plaque formation of AS and suppressed proliferation, migration, and invasion of ox-LDL-induced VSMCs via TNFRSF1A, which offered novel insights into the progression of AS.

M2 macrophage-derived exosomes promote the c-KIT phenotype of vascular smooth muscle cells during vascular tissue repair after intravascular stent implantation

Rationale: For intravascular stent implantation to be successful, the processes of vascular tissue repair and therapy are considered to be critical. However, the mechanisms underlying the eventual fate of vascular smooth muscle cells (VSMCs) during vascular tissue repair remains elusive. In this study, we hypothesized that M2 macrophage-derived exosomes to mediate cell-to-cell crosstalk and induce dedifferentiation phenotypes in VSMCs. Methods: In vivo, 316L bare metal stents (BMS) were implanted from the left iliac artery into the abdominal aorta of 12-week-old male Sprague-Dawley (SD) rats for 7 and 28 days. Hematoxylin and eosin (HE) were used to stain the neointimal lesions. En-face immunofluorescence staining of smooth muscle 22 alpha (SM22α) and CD68 showed the rat aorta smooth muscle cells (RASMCs) and macrophages. Immunohistochemical staining of total galactose-specific lectin 3 (MAC-2) and total chitinase 3-like 3 (YM-1) showed the total macrophages and M2 macrophages. In vitro, exosomes derived from IL-4+IL-13-treated macrophages (M2Es) were isolated by ultracentrifugation and characterized based on their specific morphology. Ki-67 staining was conducted to assess the effects of the M2Es on the proliferation of RASMCs. An atomic force microscope (AFM) was used to detect the stiffness of the VSMCs. GW4869 was used to inhibit exosome release. RNA-seq was performed to determine the mRNA profiles of the RASMCs and M2Es-treated RASMCs. Quantitative real-time PCR (qRT-PCR) analysis was conducted to detect the expression levels of the mRNAs. Western blotting was used to detect the candidate protein expression levels. T-5224 was used to inhibit the DNA binding activity of AP-1 in RASMCs. Results: M2Es promote c-KIT expression and softening of nearby VSMCs, hence accelerating the vascular tissue repair process. VSMCs co-cultured in vitro with M2 macrophages presented an increased capacity for de-differentiation and softening, which was exosome dependent. In addition, the isolated M2Es helped to promote VSMC dedifferentiation and softening. Furthermore, the M2Es enhanced vascular tissue repair potency by upregulation of VSMCs c-KIT expression via activation of the c-Jun/activator protein 1 (AP-1) signaling pathway. Conclusions: The findings of this study emphasize the prominent role of M2Es during VSMC dedifferentiation and vascular tissue repair via activation of the c-Jun/AP-1 signaling pathway, which has a profound impact on the therapeutic strategies of coronary stenting techniques.

PRDM16 Upregulation Induced by MicroRNA-448 Inhibition Alleviates Atherosclerosis via the TGF-β Signaling Pathway Inactivation

The dysregulated expression of microRNAs (miRs) has been associated with pathological and physiological processes of atherosclerosis (AS). In addition, PR domain-containing 16 (PRDM16), a transcriptional mediator of brown fat cell identity and smooth muscle cell activities, may be involved in the hypercholesterolemia during development of AS. The bioinformatic analysis identified a regulatory miR-448 of PRDM16. Hence, the current study aimed to explore whether miR-448 influenced the activities of aortic smooth muscle cell (ASMCs) in AS. We validated that miR-448 was highly expressed in peripheral blood of patients with AS and aortic smooth muscle of AS model mice. Whereas, PRDM16 was downregulated in the aortic smooth muscle of AS model mice. PRDM16 overexpression was observed to inhibit oxidative stress injury and cell proliferation, and promote apoptosis of ASMCs. Mechanistic studies revealed that miR-448 targeted PRDM16 and negatively regulated the PRDM16 expression, while PRDM16 blocked the TGF-β signaling pathway. Furthermore, Downregulated miR-448 alleviated oxidative stress injury, and attenuated ASMC cell proliferation, migration and enhanced cell apoptosis through upregulation of PRDM16. Taken together, silencing of miR-448 upregulates PRDM16 and inactivates the TGF-β signaling pathway, thereby impeding development of AS by repressing the proliferation, migration and invasion of ASMCs.

Exosomes: Multifaceted Messengers in Atherosclerosis

PURPOSE OF REVIEW

Atherosclerosis (AS) is a chronic inflammatory disease that contributes to the development of coronary artery disease, which has become a leading health burden worldwide. Though several strategies such as pharmacological treatment, exercise intervention, and surgery have been used in clinical practice, there is still no effective strategy to cure AS. Exosomes are extensively studied both as diagnostic markers as well as for therapeutic purposes due to their role in pathological processes related to AS. To elucidate the role of exosomes in AS and thus provide a new insight into AS therapy, we review recent advances concerning exosome targets and their function in mediating intercellular communication in AS, and expect to provide a reference for novel effective strategies to cure AS.

RECENT FINDINGS

Exosomes exert important roles in the diagnosis, development, and potential therapy of AS. For AS development, (1) activation of CD-137 in endothelial cells represses exosomal-TET2 production, causing a phenotypic switch of vascular smooth muscle cells (VSMC) and promoting plaque formation; (2) exosomal-MALTA1 derived from endothelial cells causes neutrophil extracellular traps (NETs) and M2 macrophage polarization, which aggravates AS; and (3) exosomal-miR-21-3p derived from macrophages inhibits PTEN expression and further promotes VSMC migration/proliferation, leading to AS development. For AS diagnosis, plasma exosomal-miR30e and miR-92a are considered to be potential diagnostic markers. For AS therapy, adipose mesenchymal stem cell-derived exosomes protect endothelial cells from AS aggravation, via inhibiting miR-342-5p. Exosome-mediated cross-talk between different cells within the vasculature exerts crucial roles in regulating endothelial function, proliferation and differentiation of vascular smooth muscle cells, and platelet activation as well as macrophage activation, collectively leading to the development and progression of AS. Exosomes can potentially be used as diagnostic biomarkers and constitute as a new therapeutic strategy for AS.

MicroRNA-374 is a potential diagnostic biomarker for atherosclerosis and regulates the proliferation and migration of vascular smooth muscle cells

Background

The occurrence and development of atherosclerosis (AS) are closely related to the abnormality of vascular smooth muscle cells (VSMCs), and multiple microRNAs (miRNAs) have been reported to participate in the pathogenesis of AS. This study explored the expression and clinical value of miR-374 in the serum of AS patients, and analyzed its effect on the proliferation and migration of VSMCs.

Methods

The expression levels of miR-374 in the serum of 102 asymptomatic patients with AS and 89 healthy patients were detected by fluorescence quantitative PCR. The diagnostic value of miR-374 was evaluated through the receiver operating characteristic (ROC) curve. What's more, CCK-8 and Transwell assays were used to analyze the effects of miR-374 on the proliferation and migration of VSMCs.

Results

The expression level of miR-374 in the serum of AS patients was significantly higher than that of the control group. At the same time, the expression of miR-374 in AS patients was positively correlated with carotid intima-media thickness (CIMT). The area under the ROC curve is 0.824. Furthermore, overexpression of miR-374 significantly promoted the proliferation and migration of VSMCs, whereas reducing miR-374 inhibited the proliferation and migration of VSMCs.

Conclusions

The high expression of miR-374 may be a potential diagnostic marker for AS, and overexpression of miR-374 may play a role in AS by promoting the proliferation and migration of VSMCs.

MicroRNA-21-Enriched Exosomes as Epigenetic Regulators in Melanomagenesis and Melanoma Progression: The Impact of Western Lifestyle Factors

DNA mutation-induced activation of RAS-BRAF-MEK-ERK signaling associated with intermittent or chronic ultraviolet (UV) irradiation cannot exclusively explain the excessive increase of malignant melanoma (MM) incidence since the 1950s. Malignant conversion of a melanocyte to an MM cell and metastatic MM is associated with a steady increase in microRNA-21 (miR-21). At the epigenetic level, miR-21 inhibits key tumor suppressors of the RAS-BRAF signaling pathway enhancing proliferation and MM progression. Increased MM cell levels of miR-21 either result from endogenous upregulation of melanocytic miR-21 expression or by uptake of miR-21-enriched exogenous exosomes. Based on epidemiological data and translational evidence, this review provides deeper insights into environmentally and metabolically induced exosomal miR-21 trafficking beyond UV-irradiation in melanomagenesis and MM progression. Sources of miR-21-enriched exosomes include UV-irradiated keratinocytes, adipocyte-derived exosomes in obesity, airway epithelium-derived exosomes generated by smoking and pollution, diet-related exosomes and inflammation-induced exosomes, which may synergistically increase the exosomal miR-21 burden of the melanocyte, the transformed MM cell and its tumor environment. Several therapeutic agents that suppress MM cell growth and proliferation attenuate miR-21 expression. These include miR-21 antagonists, metformin, kinase inhibitors, beta-blockers, vitamin D, and plant-derived bioactive compounds, which may represent new options for the prevention and treatment of MM.

M1 Macrophage Derived Exosomes Aggravate Experimental Autoimmune Neuritis via Modulating Th1 Response

Guillain–Barré syndrome (GBS), an immune-mediated disorder affecting the peripheral nervous system, is the most common and severe acute paralytic neuropathy. GBS remains to be potentially life-threatening and disabling despite the increasing availability of current standard therapeutic regimens. Therefore, more targeted therapeutics are in urgent need. Macrophages have been implicated in both initiation and resolution of experimental autoimmune neuritis (EAN), the animal model of GBS, but the exact mechanisms remain to be elucidated. It has been increasingly appreciated that exosomes, a type of extracellular vesicles (EVs), are of importance for functions of macrophages. Nevertheless, the roles of macrophage derived exosomes in EAN/GBS remain unclear. Here we determined the effects of macrophage derived exosomes on the development of EAN in Lewis rats. M1 macrophage derived exosomes (M1 exosomes) were found to aggravate EAN via boosting Th1 and Th17 response, while M2 macrophage derived exosomes (M2 exosomes) showed potentials to mitigate disease severity via a mechanism bypassing Th1 and Th17 response. Besides, both M1 and M2 exosomes increased germinal center reactions in EAN. Further in vitro studies confirmed that M1 exosomes could directly promote IFN-γ production in T cells and M2 exosomes were not capable of inhibiting IFN-γ expression. Thus, our data identify a previously undescribed means that M1 macrophages amplify Th1 response via exosomes and provide novel insights into the crosstalk between macrophages and T cells as well.

MicroRNA-21-3p Engineered Umbilical Cord Stem Cell-Derived Exosomes Inhibit Tendon Adhesion

Purpose

As a common complication of tendon injury, tendon adhesion is an unresolved problem in clinical work. The aim of this study was to investigate whether human umbilical cord mesenchymal stem cell-derived exosomes (HUMSC-Exos), one of the most promising new-generation cell-free therapeutic agents, can improve tendon adhesion and explore potential-related mechanisms.

Methods

The rat Achilles tendon injury adhesion model was constructed in vivo, and the localization of HUMSC-Exos was used to evaluate the tendon adhesion. Rat fibroblast cell lines were treated with transforming growth factor β1 (TGF-β1) and/or HUMSC-Exos in vitro, and cell proliferation, apoptosis and gene expression were measured. MicroRNA (miRNA) sequencing and quantitative PCR (qPCR) analysis confirmed differential miRNAs. A specific miRNA antagonist (antagomir-21a-5p) was used to transform HUMSC-Exos and obtain modified exosomes to verify its efficacy and related mechanism of action.

Results

In this study, we found HUMSC-Exos reduced rat fibroblast proliferation and inhibited the expression of fibrosis genes: collagen III (COL III) and α-smooth muscle actin (α-SMA) in vitro. In the rat tendon adhesion model, topical application of HUMSC-Exos contributed to relief of tendon adhesion. Specifically, the fibrosis and inflammation-related genes were simultaneously inhibited by HUMSC-Exos. Further, miRNA sequencing of HUMSCs and HUMSC-Exos showed that miR-21a-3p was expressed at low abundance in HUMSC-Exos. The antagonist targeting miR-21a-3p was recruited for treatment of HUMSCs, and harvested HUMSC-Exos, which expressed low levels of miR-21a-3p, and expanded the inhibition of tendon adhesion in subsequent in vitro experiments.

Conclusion

Our results indicate that HUMSC-Exos may manipulate p65 activity by delivering low-abundance miR-21a-3p, ultimately inhibiting tendon adhesion. The findings may be promising for dealing with tendon adhesion.

The lncRNA GAS5 Inhibits the Osteogenic Differentiation and Calcification of Human Vascular Smooth Muscle Cells

Vascular calcification (VC), which is associated with high cardiovascular morbidity and mortality in patients with chronic kidney disease, is promoted by the osteoblastic differentiation of vascular smooth muscle cells (VSMCs). The present study explored the functional roles and molecular mechanisms of the long noncoding RNA growth arrest-specific transcript 5 (GAS5) in VC. Our results indicated that GAS5 was clearly downregulated in calcified human aortic vascular smooth muscle cells (HASMCs). Functionally, we found that overexpression of GAS5 significantly attenuated the osteogenic differentiation and calcification of HASMCs induced by high levels of phosphorus. Moreover, miR-26-5p was identified to potentially bind to GAS5, and phosphatase and tensin homolog (PTEN) was determined to be a direct target of miR-26b-5p in HASMCs. Mechanistically, enforced expression of miR-26-5p significantly attenuated PTEN protein expression in HASMCs. Rescue experiments demonstrated that cotransfection of HASMCs with miR-26-5p mimics reduced the inhibition of Lv-GAS5 on osteogenic differentiation and calcification. As a result, GAS5 was confirmed to be an miR-26b-5p sponge and to thereby increase the expression of PTEN in HASMCs. In ex vivo models, GAS5 was significantly downregulated and its expression inversely related to the expression of miR-26b-5 and positively associated with the expression of PTEN in calcified aortic rings induced by high levels of phosphorus. Together, these results suggest that the GAS5/miR-26-5p/PTEN axis could serve as a potential therapeutic target for VC in patients with chronic kidney disease.

Nicotine in Senescence and Atherosclerosis

Cigarette smoke is a known exacerbator of age-related pathologies, such as cardiovascular disease (CVD), atherosclerosis, and cellular aging (senescence). However, the role of nicotine and its major metabolite cotinine is yet to be elucidated. Considering the growing amount of nicotine-containing aerosol use in recent years, the role of nicotine is a relevant public health concern. A number of recent studies and health education sites have focused on nicotine aerosol-induced adverse lung function, and neglected cardiovascular (CV) impairments and diseases. A critical review of the present scientific literature leads to the hypothesis that nicotine mediates the effects of cigarette smoke in the CV system by increasing MAPK signaling, inflammation, and oxidative stress through NADPH oxidase 1 (Nox1), to induce vascular smooth muscle cell (VSMC) senescence. The accumulation of senescent VSMCs in the lesion cap is detrimental as it increases the pathogenesis of atherosclerosis by promoting an unstable plaque phenotype. Therefore, nicotine, and most likely its metabolite cotinine, adversely influence atherosclerosis.

Endothelial to mesenchymal transition contributes to nicotine-induced atherosclerosis

Rationale: Nicotine exposure via cigarette smoking is strongly associated with atherosclerosis. However, the underlying mechanisms remain poorly understood. The current study aimed to identify whether endothelial to mesenchymal transition (EndMT) contributes to nicotine-induced atherosclerosis. Methods: ApoE-/- mice were administered nicotine in their drinking water for 12 weeks. The effects of nicotine on EndMT were determined by immunostaining on aortic root and RNA analysis in aortic intima. In vitro nicotine-treated cell model was established on human aortic endothelial cells (HAECs). The effects of nicotine on the expression of EndMT-related markers, ERK1/2 and Snail were quantified by real-time PCR, western blot and immunofluorescent staining. Results: Nicotine treatment resulted in larger atherosclerotic plaques in ApoE-/- mice. The vascular endothelial cells from nicotine-treated mice showed mesenchymal phenotype, indicating EndMT. Moreover, nicotine-induced EndMT process was accompanied by cytoskeleton reorganization and impaired barrier function. The α7 nicotine acetylcholine receptor (α7nAChR) was highly expressed in HAECs and its antagonist could effectively relieve nicotine-induced EndMT and atherosclerotic lesions in mice. Further experiments revealed that ERK1/2 signaling was activated by nicotine, which led to the upregulation of Snail. Blocking ERK1/2 with inhibitor or silencing Snail by small interfering RNA efficiently preserved endothelial phenotype upon nicotine stimulation. Conclusion: Our study provides evidence that EndMT contributes to the pro-atherosclerotic property of nicotine. Nicotine induces EndMT through α7nAChR-ERK1/2-Snail signaling in endothelial cells. EndMT may be a therapeutic target for smoking-related endothelial dysfunction and cardiovascular disease.

Inside(sight) of tiny communicator: exosome biogenesis, secretion, and uptake

Discovered in the late 1980s as an extracellular vesicle of endosomal origin secreted from reticulocytes, exosomes recently gained scientific attention due to its role in intercellular communication. Exosomes have now been identified to carry cell-specific cargo of nucleic acids, proteins, lipids, and other biologically active molecules. Exosomes can be selectively taken up by neighboring or distant cells, which has shown to result in structural and functional responses in the recipient cells. Recent advances indicate the regulation of exosomes at various steps, including their biogenesis, selection of their cargo, as well as cell-specific uptake. This review will shed light on the differences between the type of extracellular vesicles. In this review, we discuss the recent progress in our understanding of the regulation of exosome biogenesis, secretion, and uptake.

Progress, opportunity, and perspective on exosome isolation - efforts for efficient exosome-based theranostics

Exosomes are small extracellular vesicles with diameters of 30-150 nm. In both physiological and pathological conditions, nearly all types of cells can release exosomes, which play important roles in cell communication and epigenetic regulation by transporting crucial protein and genetic materials such as miRNA, mRNA, and DNA. Consequently, exosome-based disease diagnosis and therapeutic methods have been intensively investigated. However, as in any natural science field, the in-depth investigation of exosomes relies heavily on technological advances. Historically, the two main technical hindrances that have restricted the basic and applied researches of exosomes include, first, how to simplify the extraction and improve the yield of exosomes and, second, how to effectively distinguish exosomes from other extracellular vesicles, especially functional microvesicles. Over the past few decades, although a standardized exosome isolation method has still not become available, a number of techniques have been established through exploration of the biochemical and physicochemical features of exosomes. In this work, by comprehensively analyzing the progresses in exosome separation strategies, we provide a panoramic view of current exosome isolation techniques, providing perspectives toward the development of novel approaches for high-efficient exosome isolation from various types of biological matrices. In addition, from the perspective of exosome-based diagnosis and therapeutics, we emphasize the issue of quantitative exosome and microvesicle separation.

The interaction between STAT3 and nAChRα1 interferes with nicotine-induced atherosclerosis via Akt/mTOR signaling cascade

During atherosclerosis development, nicotine and its α1 nicotinic acetylcholine receptors (nAChRα1) activate atherogenic inflammation. However, the effect of signal transducer and activator of transcription 3 (STAT3)-related inflammatory pathways in nicotine-induced atherosclerosis has been poorly studied. This study investigated the transcriptional mechanism of STAT3 in nicotine/nAChRα1-induced atherosclerosis. In vivo, ApoE-/- mice were used to establish an atherosclerotic model. Plaque area and composition were assessed by oil red O staining and immunohistochemistry. In vitro, vascular smooth muscle cells and macrophages were used to investigate cell migration, proliferation, inflammation and related signaling pathways by Transwell migration assay, EdU assay, immunofluorescence, western blotting, coimmunoprecipitation and chromatin immunoprecipitation. nAChRα1 knockdown significantly decreases the nicotine-induced upregulation of p-STAT3, p-Akt and p-mTOR in vitro, while nAChRα1 overexpression has the opposite effects. The inhibition of STAT3 attenuated nicotine-induced atherosclerosis, by reducing the proliferation and migration of vascular smooth muscle cells and inflammation in macrophages. Moreover, there is a direct interaction between STAT3 and nAChRα1 that modulates STAT3 nuclear translocation and its binding to the Akt promoter region upon nicotine exposure. Taken together, STAT3 and nAChRα1 blockade attenuates nicotine-induced atherosclerosis by reducing the migration and proliferation of vascular smooth muscle cells and inflammation in macrophages via the Akt/mTOR pathway.