MicroRNA-10A* and MicroRNA-21 modulate endothelial progenitor cell senescence via suppressing high-mobility group A2

MicroRNA-29c-3p and -126a Contribute to the Decreased Angiogenic Potential of Aging Endothelial Progenitor Cells

EPCs play important roles in the maintenance of vascular repair and health. Aging is associated with both reduced numbers and functional impairment of EPCs, leading to diminished angiogenic capacity, impaired cardiac repair, and increased risk for cardiovascular disease (CVD). The molecular mechanisms that govern EPC function in cardiovascular health are not fully understood, but there is increasing evidence that microRNAs (miRNAs) play key roles in modulating EPC functionality, endothelial homeostasis, and vascular repair. We aimed to determine how aging alters endothelial progenitor (EPC) health and functionality by altering key miRNA-mRNA pathways. To identify key miRNA-mRNA pathways contributing to diminished EPC functionality associated with aging, microRNA and mRNA profiling were conducted in EPCs from young and aged C57BL/6 mice. We identified a complex aging-associated regulatory network involving two miRNAs-miR-29c-3p and -126a-that acted in tandem to impair vascular endothelial growth factor signaling through targeting Klf2 and Spred1, respectively. The modulation of components of the miR-29c-3p-Klf2-miR-126a-Spred-1-Vegf signaling pathway altered EPC self-renewal capacity, vascular tube formation, and migration in vitro, as well as cardiac repair in vivo. The miR-29c-3p-Klf2-miR-126a-Spred1-Vegf signaling axis plays a critical role in regulating the aging-associated deficits in EPC-mediated vascular repair and CVD risk.

Cellular Phenotypic Transformation During Atherosclerosis: The Potential Role of miRNAs as Biomarkers

Cellular phenotypic transformation is a key process that occurs during the development and progression of atherosclerosis. Within the arterial wall, endothelial cells, vascular smooth muscle cells, and macrophages undergo phenotypic changes that contribute to the pathogenesis of atherosclerosis. miRNAs have emerged as potential biomarkers for cellular phenotypic changes during atherosclerosis. Monitoring miR-155-5p, miR-210-3p, and miR-126-3p or 5p levels could provide valuable insights into disease progression, risk of complications, and response to therapeutic interventions. Moreover, miR-92a-3p's elevated levels in atherosclerotic plaques present opportunities for predicting disease progression and related complications. Baseline levels of miR-33a/b hold the potential for predicting responses to cholesterol-lowering therapies, such as statins, and the likelihood of dyslipidemia-related complications. Additionally, the assessment of miR-122-5p levels may offer insights into the efficacy of low-density-lipoprotein-lowering therapies. Understanding the specific miRNA-mediated regulatory mechanisms involved in cellular phenotypic transformations can provide valuable insights into the pathogenesis of atherosclerosis and potentially identify novel therapeutic targets.

The interplay of p16INK4a and non-coding RNAs: bridging cellular senescence, aging, and cancer

p16INK4a is a crucial tumor suppressor and regulator of cellular senescence, forming a molecular bridge between aging and cancer. Dysregulated p16INK4a expression is linked to both premature aging and cancer progression, where non-coding RNAs (ncRNAs) such as long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and small interfering RNAs (siRNAs) play key roles in modulating its function. These ncRNAs interact with p16INK4a through complex post-transcriptional and epigenetic mechanisms, influencing pathways critical to senescence and tumor suppression. In this review, we explore ncRNAs, including ANRIL, MIR31HG, UCA1, MALAT1, miR-24, miR-30, and miR-141, which collectively regulate p16INK4a expression, promoting or inhibiting pathways associated with cancer and aging. ANRIL and MIR31HG modulate p16INK4a silencing via interactions with polycomb repressive complexes (PRC), while miRNAs such as miR-24 and miR-30 target p16INK4a to influence cellular proliferation and senescence. This regulatory interplay underscores the therapeutic potential of ncRNA-targeted strategies to restore p16INK4a function. We summarize recent studies supporting that ncRNAs that control p16INK4a may be diagnostic biomarkers and therapeutic targets for age-related diseases and cancer.

Genomic variation responding to artificial selection on different lines of Pekin duck

Understanding the genomic variation in Pekin duck under artificial selection is important for improving the utilization of duck genetic resources. Here, the genomic changes in Pekin duck were analyzed by using the genome resequencing data from 96 individual samples, including 2 conservation populations and 4 breeding populations with different breeding backgrounds. The population structure, runs of homozygosity (ROH), effective population number (Ne), and other genetic parameters were analyzed. The breeding populations showed lower genetic diversity compared to the conservation populations. Maple Leaf duck and Cherry Valley duck retained low genetic diversity compared to other breeding populations, with Cherry Valley duck showing the lowest diversity and the highest inbreeding coefficient. This suggested that Cherry Valley and Maple Leaf ducks have undergone intensive selection compared to other breeding populations. By the analysis of runs of homozygosity (ROHs), some genes (e.g., IGF1R) associated with growth traits were identified. By the analysis of the selection signal, strong selection characteristics in certain genomic regions during the breeding of Peking duck across different selected lines were observed. In addition, copy number variations (CNVs) in Pekin duck populations were analyzed. Six regions of interest were identified, containing RPA1, DOT1L, SLC25A42, RALYL, TRPA1, and IGFBP2. Furthermore, the allele frequency distribution of these genes showed significant differences between breeding populations and conservation populations, indicating that these candidate genes could have undergone strong selection pressure during long-term selection for improved production. These findings contribute to a deeper understanding of the distinct evolutionary processes in Pekin ducks under artificial selection and provide valuable insights for future breeding strategies.

Anti-inflammatory Prowess of endothelial progenitor cells in the realm of biology and medicine

Endothelial inflammation plays a crucial role in vascular-related diseases, a leading cause of global mortality. Among various cellular players, endothelial progenitor cells (EPCs) emerge as non-differentiated endothelial cells circulating in the bloodstream. Recent evidence highlights the transformative role of EPCs in shifting from an inflammatory/immunosuppressive crisis to an anti-inflammatory/immunomodulatory response. Despite the importance of these functions, the regulatory mechanisms governing EPC activities and their physiological significance in vascular regenerative medicine remain elusive. Surprisingly, the current literature lacks a comprehensive review of EPCs' effects on inflammatory processes. This narrative review aims to fill this gap by exploring the cutting-edge role of EPCs against inflammation, from molecular intricacies to broader medical perspectives. By examining how EPCs modulate inflammatory responses, we aim to unravel their anti-inflammatory significance in vascular regenerative medicine, deepening insights into EPCs' molecular mechanisms and guiding future therapeutic strategies targeting vascular-related diseases.

Hsa-miR-134-5p predicts cardiovascular risk in circulating mononuclear cells and improves angiogenic action of senescent endothelial progenitor cells

This research explores the role of microRNA in senescence of human endothelial progenitor cells (EPCs) induced by replication. Hsa-miR-134-5p was found up-regulated in senescent EPCs where overexpression improved angiogenic activity. Hsa-miR-134-5p, which targeted transforming growth factor β-activated kinase 1-binding protein 1 (TAB1) gene, down-regulated TAB1 protein, and inhibited phosphorylation of p38 mitogen-activated protein kinase (p38) in hsa-miR-134-5p-overexpressed senescent EPCs. Treatment with siRNA specific to TAB1 (TAB1si) down-regulated TAB1 protein and subsequently inhibited p38 activation in senescent EPCs. Treatment with TAB1si and p38 inhibitor, respectively, showed angiogenic improvement. In parallel, transforming growth factor Beta 1 (TGF-β1) was down-regulated in hsa-miR-134-5p-overexpressed senescent EPCs and addition of TGF-β1 suppressed the angiogenic improvement. Analysis of peripheral blood mononuclear cells (PBMCs) disclosed expression levels of hsa-miR-134-5p altered in adult life, reaching a peak before 65 years, and then falling in advanced age. Calculation of the Framingham risk score showed the score inversely correlates with the hsa-miR-134-5p expression level. In summary, hsa-miR-134-5p is involved in the regulation of senescence-related change of angiogenic activity via TAB1-p38 signalling and via TGF-β1 reduction. Hsa-miR-134-5p has a potential cellular rejuvenation effect in human senescent EPCs. Detection of human PBMC-derived hsa-miR-134-5p predicts cardiovascular risk.

Macrophages and tumor-associated macrophages in the senescent microenvironment: From immunosuppressive TME to targeted tumor therapy

In-depth studies of the tumor microenvironment (TME) have helped to elucidate its cancer-promoting mechanisms and inherent characteristics. Cellular senescence, which acts as a response to injury and can the release of senescence-associated secretory phenotypes (SASPs). These SASPs release various cytokines, chemokines, and growth factors, remodeling the TME. This continual development of a senescent environment could be associated with chronic inflammation and immunosuppressive TME. Additionally, SASPs could influence the phenotype and function of macrophages, leading to the recruitment of tumor-associated macrophages (TAMs). This contributes to tumor proliferation and metastasis in the senescent microenvironment, working in tandem with immune regulation, angiogenesis, and therapeutic resistance. This comprehensive review covers the evolving nature of the senescent microenvironment, macrophages, and TAMs in tumor development. We also explored the links between chronic inflammation, immunosuppressive TME, cellular senescence, and macrophages. Moreover, we compiled various tumor-specific treatment strategies centered on cellular senescence and the current challenges in cellular senescence research. This study aimed to clarify the mechanism of macrophages and the senescent microenvironment in tumor progression and advance the development of targeted tumor therapies.

AMPK-upregulated microRNA-708 plays as a suppressor of cellular senescence and aging via downregulating disabled-2 and mTORC1 activation

Senescence-associated microRNAs (SA-miRNAs) are important molecules for aging regulation. While many aging-promoting SA-miRNAs have been identified, confirmed aging-suppressive SA-miRNAs are rare, that impeded our full understanding on aging regulation. In this study, we verified that miR-708 expression is decreased in senescent cells and aged tissues and revealed that miR-708 overexpression can alleviate cellular senescence and aging performance. About the molecular cascade carrying the aging suppressive action of miR-708, we unraveled that miR-708 directly targets the 3'UTR of the disabled 2 (Dab2) gene and inhibits the expression of DAB2. Interestingly, miR-708-caused DAB2 downregulation blocks the aberrant mammalian target of rapamycin complex 1 (mTORC1) activation, a driving metabolic event for senescence progression, and restores the impaired autophagy, a downstream event of aberrant mTORC1 activation. We also found that AMP-activated protein kinase (AMPK) activation can upregulate miR-708 via the elevation of DICER expression, and miR-708 inhibitor is able to blunt the antiaging effect of AMPK. In summary, this study characterized miR-708 as an aging-suppressive SA-miRNA for the first time and uncovered a new signaling cascade, in which miR-708 links the DAB2/mTOR axis and AMPK/DICER axis together. These findings not only demonstrate the potential role of miR-708 in aging regulation, but also expand the signaling network connecting AMPK and mTORC1.

Extracellular Vesicles as Delivery Systems in Disease Therapy

Extracellular vesicles (EVs)/exosomes are nanosized membrane-bound structures that are released by virtually all cells. EVs have attracted great attention in the scientific community since the discovery of their roles in cell-to-cell communication. EVs' enclosed structure protects bioactive molecules from degradation in the extracellular space and targets specific tissues according to the topography of membrane proteins. Upon absorption by recipient cells, EV cargo can modify the transcription machinery and alter the cellular functions of these cells, playing a role in disease pathogenesis. EVs have been tested as the delivery system for the mRNA COVID-19 vaccine. Recently, different therapeutic strategies have been designed to use EVs as a delivery system for microRNAs and mRNA. In this review, we will focus on the exciting and various platforms related to using EVs as delivery vehicles, mainly in gene editing using CRISPR/Cas9, cancer therapy, drug delivery, and vaccines. We will also touch upon their roles in disease pathogenesis.

Single-cell transcriptomics implicates the FEZ1-DKK1 axis in the regulation of corneal epithelial cell proliferation and senescence

Limbal stem/progenitor cells (LSC) represent the source of corneal epithelium renewal. LSC proliferation and differentiation are essential for corneal homeostasis, however, the regulatory mechanism remains largely unexplored. Here, we performed single-cell RNA sequencing and discovered proliferation heterogeneity as well as spontaneously differentiated and senescent cell subgroups in multiply passaged primary LSC. Fasciculation and elongation protein zeta 1 (FEZ1) and Dickkopf-1 (DKK1) were identified as two significant regulators of LSC proliferation and senescence. These two factors were mainly expressed in undifferentiated corneal epithelial cells (CECs). Knocking down the expression of either FEZ1 or DKK1 reduced cell division and caused cell cycle arrest. We observed that DKK1 acted as a downstream target of FEZ1 in LSC and that exogenous DKK1 protein partially prevented growth arrest and senescence upon FEZ1 suppression in vitro. In a mouse model of corneal injury, DKK1 also rescued the corneal epithelium after recovery was inhibited by FEZ1 suppression. Hence, the FEZ1-DKK1 axis was required for CEC proliferation and the juvenile state and can potentially be targeted as a therapeutic strategy for promoting recovery after corneal injury.

HIV Promotes Atherosclerosis via Circulating Extracellular Vesicle MicroRNAs

People living with HIV (PLHIV) are at a higher risk of having cerebrocardiovascular diseases (CVD) compared to HIV negative (HIVneg) individuals. The mechanisms underlying this elevated risk remains elusive. We hypothesize that HIV infection results in modified microRNA (miR) content in plasma extracellular vesicles (EVs), which modulates the functionality of vascular repairing cells, i.e., endothelial colony-forming cells (ECFCs) in humans or lineage negative bone marrow cells (lin- BMCs) in mice, and vascular wall cells. PLHIV (N = 74) have increased atherosclerosis and fewer ECFCs than HIVneg individuals (N = 23). Plasma from PLHIV was fractionated into EVs (HIVposEVs) and plasma depleted of EVs (HIV PLdepEVs). HIVposEVs, but not HIV PLdepEVs or HIVnegEVs (EVs from HIVneg individuals), increased atherosclerosis in apoE-/- mice, which was accompanied by elevated senescence and impaired functionality of arterial cells and lin- BMCs. Small RNA-seq identified EV-miRs overrepresented in HIVposEVs, including let-7b-5p. MSC (mesenchymal stromal cell)-derived tailored EVs (TEVs) loaded with the antagomir for let-7b-5p (miRZip-let-7b) counteracted, while TEVs loaded with let-7b-5p recapitulated the effects of HIVposEVs in vivo. Lin- BMCs overexpressing Hmga2 (a let-7b-5p target gene) lacking the 3'UTR and as such is resistant to miR-mediated regulation showed protection against HIVposEVs-induced changes in lin- BMCs in vitro. Our data provide a mechanism to explain, at least in part, the increased CVD risk seen in PLHIV.

Role of noncoding RNAs in cardiac ageing

The global population is estimated to reach 9.8 billion by 2050, of which 2.1 billion will comprise individuals above 60 years of age. As the number of elderly is estimated to double from 2017, it is a victory of the modern healthcare system but also worrisome as ageing, and the onset of chronic disease are correlated. Among other chronic conditions, cardiovascular diseases (CVDs) are the leading cause of death in the aged population. While the underlying cause of the age-associated development of CVDs is not fully understood, studies indicate the role of non-coding RNAs such as microRNAs (miRNAs) and long noncoding RNAs (lnc-RNAs) in the development of age-associated CVDs. miRNAs and lnc-RNAs are non-coding RNAs which control gene expression at the post-transcriptional level. The expression of specific miRNAs and lnc-RNAs are reportedly dysregulated with age, leading to cardiovascular system changes and ultimately causing CVDs. Since miRNAs and lnc-RNAs play several vital roles in maintaining the normal functioning of the cardiovascular system, they are also being explored for their therapeutic potential as a treatment for CVDs. This review will first explore the pathophysiological changes associated with ageing. Next, we will review the known mechanisms underlying the development of CVD in ageing with a specific focus on miRNA and lnc-RNAs. Finally, we will discuss the therapeutic options and future challenges towards healthy cardiac ageing. With the global ageing population on the rise, this review will provide a fundamental understanding of some of the underlying molecular mechanisms of cardiac ageing.

Aging microenvironment and antitumor immunity for geriatric oncology: the landscape and future implications

The tumor microenvironment (TME) has been extensively investigated; however, it is complex and remains unclear, especially in elderly patients. Senescence is a cellular response to a variety of stress signals, which is characterized by stable arrest of the cell cycle and major changes in cell morphology and physiology. To the best of our knowledge, senescence leads to consistent arrest of tumor cells and remodeling of the tumor-immune microenvironment (TIME) by activating a set of pleiotropic cytokines, chemokines, growth factors, and proteinases, which constitute the senescence-associated secretory phenotype (SASP). On the one hand, the SASP promotes antitumor immunity, which enhances treatment efficacy; on the other hand, the SASP increases immunosuppressive cell infiltration, including myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), M2 macrophages, and N2 neutrophils, contributing to TIME suppression. Therefore, a deeper understanding of the regulation of the SASP and components contributing to robust antitumor immunity in elderly individuals with different cancer types and the available therapies is necessary to control tumor cell senescence and provide greater clinical benefits to patients. In this review, we summarize the key biological functions mediated by cytokines and intercellular interactions and significant components of the TME landscape, which influence the immunotherapy response in geriatric oncology. Furthermore, we summarize recent advances in clinical practices targeting TME components and discuss potential senescent TME targets.

Hsa-miR-409-3p regulates endothelial progenitor senescence via PP2A-P38 and is a potential ageing marker in humans

We explored the roles of hsa-microRNA (miR)-409-3p in senescence and signalling mechanism of human endothelial progenitor cells (EPCs). Hsa-miR-409-3p was found upregulated in senescent EPCs. Overexpression of miRNA mimics in young EPCs inhibited angiogenesis. In senescent EPCs, compared to young EPCs, protein phosphatase 2A (PP2A) was downregulated, with activation of p38/JNK by phosphorylation. Young EPCs treated with siPP2A caused inhibited angiogenesis with activation of p38/JNK, similar to findings in senescent EPCs. Time series analysis showed, in young EPCs treated with hsa-miR-409-3p mimics, PP2A was steadily downregulated for 72 h, while p38/JNK was activated with a peak at 48 hours. The inhibited angiogenesis of young EPCs after miRNA-409-3p mimics treatment was reversed by the p38 inhibitor. The effect of hsa-miR-409-3p on PP2A signalling was attenuated by exogenous VEGF. Analysis of human peripheral blood mononuclear cells (PBMCs) obtained from healthy people revealed hsa-miR-409-3p expression was higher in those older than 65 years, compared to those younger than 30 years, regardless of gender. In summary, hsa-miR-409-3p was upregulated in senescent EPCs and acted as a negative modulator of angiogenesis via targeting protein phosphatase 2 catalytic subunit alpha (PPP2CA) gene and regulating PP2A/p38 signalling. Data from human PBMCs suggested hsa-miR-409-3p a potential biomarker for human ageing.

The Role of miRNA in the Regulation of Angiogenesis in Ischemic Heart Disease

Despite continued improvements in primary prevention and treatment, ischemic heart disease (IHD) is the most common cause of mortality in both developing and developed countries. Promoting angiogenesis and reconstructing vascular network in ischemic myocardium are critical process of postischemic tissue repair. Effective strategies to promote survival and avoid apoptosis of endothelial cells in the ischemic myocardium can help to achieve long-term cardiac angiogenesis. Therefore, it is of great importance to investigate the molecular pathophysiology of angiogenesis in-depth and to find the key targets that promote angiogenesis. Recently years, many studies have found that microRNAs play important regulatory roles in almost all process of angiogenesis, including vascular sprouting, proliferation, survival and migration of vascular endothelial cells, recruitment of vascular progenitor cells, and control of angiopoietin expression. This review presents detailed information about the regulatory role of miRNAs in the angiogenesis of IHD in recent years, and provides new therapeutic ideas for the treatment of IHD.

Endothelial miR-196b-5p regulates angiogenesis via the hypoxia/miR-196b-5p/HMGA2/HIF1α loop

Angiogenesis is involved in development, reproduction, wound healing, homeostasis, and other pathophysiological events. Imbalanced angiogenesis predisposes patients to various pathological processes, such as angiocardiopathy, inflammation, and tumorigenesis. MicroRNAs (miRNAs) have been found to be important in regulating cellular processing and physiological events including angiogenesis. However, the role of miRNAs that regulate angiogenesis (angiomiRs) is not fully understood. Here, we observed a downregulation of the miR-196 family in endothelial cells upon hypoxia. Functionally, miR-196b-5p inhibited the angiogenic functions of endothelial cells in vitro and suppressed angiogenesis in Matrigel plugs and skin wound healing in vivo. Mechanistically, miR-196b-5p bound onto the 3' untranslated region (UTR) of high-mobility group AT-hook 2 (HMGA2) mRNA and repressed the translation of HMGA2, which in turn represses HIF1α accumulation in endothelial cells upon hypoxia. Together, our results establish the role of endothelial miR-196b-5p as an angiomiR that negatively regulates endothelial growth in angiogenesis via the hypoxia/miR-196b-5p/HMGA2/HIF1α loop. miR-196b-5p and its regulatory loop could be an important addition to the molecular mechanisms underlying angiogenesis and may serve as potential targets for antiangiogenic therapy.

VascuFit: vascular effects of non-linear periodized exercise training in sedentary adults with elevated cardiovascular risk - protocol for a randomized controlled trial

Background

Early vascular aging (EVA) is increasingly prevalent in the general population. Exercise is important for primary cardiovascular prevention, but often insufficient due to ineffective training methods and a lack of biomarkers suitable to monitor its vascular effects. VascuFit will assess the effectiveness of non-linear periodized aerobic exercise (NLPE) in a non-athletic sedentary population to improve both established and promising biomarkers of EVA.

Methods

Forty-three sedentary adults, aged 40–60 years, with elevated cardiovascular risk will either engage in 8 weeks of ergometer-based NLPE (n = 28) or receive standard exercise recommendations (n = 15). The primary outcome will be the change of brachial-arterial flow-mediated dilation (baFMD) after versus before the intervention. Secondary outcomes will be the change in static vessel analysis (SVA; clinical biomarker of microvascular endothelial function), endomiRs (microRNAs regulating key molecular pathways of endothelial cell homeostasis) and circulating cellular markers of endothelial function (mature endothelial cells, endothelial progenitor cells). Tertiary outcomes will be the change in sphingolipidome, maximum oxygen capacity, and traditional cardiovascular risk factors (blood pressure, triglycerides, cholesterol, fasting glucose, high-sensitivity C-reactive protein).

Discussion

We expect an improvement of baFMD of at least 2.6% and significant pre-post intervention differences of SVA and endomiRs as well as of the tertiary outcomes in the intervention group. VascuFit may demonstrate the effectiveness of NLPE to improve endothelial function, thus vascular health, in the general sedentary population. Furthermore, this project might demonstrate the potential of selected molecular and cellular biomarkers to monitor endothelial adaptations to aerobic exercise.

Trial registration

The trial was registered on www.clinicaltrials.gov (NCT05235958) in February 11^th 2022.

Identification of Four Biomarkers of Human Skin Aging by Comprehensive Single Cell Transcriptome, Transcriptome, and Proteomics

Background: Aging is characterized by the gradual loss of physiological integrity, resulting in impaired function and easier death. This deterioration is a major risk factor for major human pathological diseases, including cancer, diabetes, cardiovascular disease and neurodegenerative diseases. It is very important to find biomarkers that can prevent aging.

Methods: Q-Exactive-MS was used for proteomic detection of young and senescence fibroblast. The key senescence-related molecules (SRMs) were identified by integrating transcriptome and proteomics from aging tissue/cells, and the correlation between these differentially expressed genes and well-known aging-related pathways. Next, we validated the expression of these molecules using qPCR, and explored the correlation between them and immune infiltrating cells. Finally, the enriched pathways of the genes significantly related to the four differential genes were identified using the single cell transcriptome.

Results: we first combined proteomics and transcriptome to identified four SRMs. Data sets including GSE63577, GSE64553, GSE18876, GSE85358, and qPCR confirmed that ETF1, PLBD2, ASAH1, and MOXD1 were identified as SRMs. Then the correlation between SRMs and aging-related pathways was excavated and verified. Next, we verified the expression of SRMs at the tissue level and qPCR, and explored the correlation between them and immune infiltrating cells. Finally, at the single-cell transcriptome level, we verified their expression and explored the possible pathway by which they lead to aging. Briefly, ETF1 may affect the changes of inflammatory factors such as IL-17, IL-6, and NFKB1 by indirectly regulating the enrichment and differentiation of immune cells. MOXD1 may regulate senescence by affecting the WNT pathway and changing the cell cycle. ASAH1 may affect development and regulate the phenotype of aging by affecting cell cycle-related genes.

Conclusion: In general, based on the analysis of proteomics and transcriptome, we identified four SRMs that may affect aging and speculated their possible mechanisms, which provides a new target for preventing aging, especially skin aging.

Theories and Molecular Basis of Vascular Aging: A Review of the Literature from VascAgeNet Group on Pathophysiological Mechanisms of Vascular Aging

Vascular aging, characterized by structural and functional alterations of the vascular wall, is a hallmark of aging and is tightly related to the development of cardiovascular mortality and age-associated vascular pathologies. Over the last years, extensive and ongoing research has highlighted several sophisticated molecular mechanisms that are involved in the pathophysiology of vascular aging. A more thorough understanding of these mechanisms could help to provide a new insight into the complex biology of this non-reversible vascular process and direct future interventions to improve longevity. In this review, we discuss the role of the most important molecular pathways involved in vascular ageing including oxidative stress, vascular inflammation, extracellular matrix metalloproteinases activity, epigenetic regulation, telomere shortening, senescence and autophagy.

Role of MicroRNAs in acceleration of vascular endothelial senescence

Backgrounds

Many factors are involved in cellular aging, and senescence induction requires complex regulation of various signaling networks and processes. Specifically, in the area of aging-related vascular cognitive impairment, laboratory-based findings have not yet yielded agents of practical use for clinical settings. One possible reason is that the physiologic elements of aging have been insufficiently considered. We sought to establish techniques to better model cellular aging using modulation of microRNAs, aiming to identify key microRNAs capable of fine-tuning aging-associated genes, and thereby regulating the senescence of vascular endothelial cells.

Methods

We utilized expression microRNA arrays to evaluate control and senescent vascular endothelial cells in order to identify testable candidates. Bioinformatic analysis was used to select key microRNAs. These candidates were then modulated in vitro using microRNA mimics and inhibitors in endothelial cells, and senescence-associated gene expression patterns were evaluated by qPCR.

Results

Seventeen microRNAs were found to be significantly increased more than 2-fold in senescent cells. Of those, bioinformatic analysis concluded that miR-181a-5p, miR-30a-5p, miR-30a-3p, miR-100-5p, miR-21-5p, and miR-382-5p were likely associated with regulation of cellular senescence. We evaluated the potential targets of these six microRNAs by comparing them with cell-cycling and apoptosis-related genes from published mRNA transcriptional array data from aged tissues, and found that miR-181a-5p, miR-30a-5p and miR-30a-3p were enriched in overlapping targets compared with the other candidates. Modulation of these microRNAs in vascular endothelial cells revealed that over-expression of miR-30a-5p, and inhibition of both miR-30a-3p and miR-181a-5p, induced senescence.

Conclusion:

miR-181a-5p, miR-30a-5p and miR-30a-3p likely contribute to aging-associated vascular endothelial cell senescence.

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We aimed to identify key microRNAs regulating the senescence of vascular ECs.

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Bioinformatic analysis indicated miR-181a-5p, miR-30a-5p & 30a-3p as candidates.

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Overexpression of miR-30a-5p & inhibition of miR-30a-3p/181a-5p induce EC senescence.

miR-548j-5p regulates angiogenesis in peripheral artery disease

Peripheral artery disease (PAD) is a vascular disease involving diffuse atherosclerosis, and is associated with increased cardiovascular mortality and morbidity. Critical limb ischemia (CLI) is the most severe complication of PAD. In addition to medical and interventional treatment, therapeutic angiogenesis is a novel therapy for PAD. Circulating microRNAs (miRNAs) are considered key regulators of gene expression, but their role in ischemic-induced angiogenesis is poorly-characterized. There is currently a limited understanding of the specific miRNAs associated with PAD. To determine the regulation of miRNAs, we obtained miRNA profiles using RNA isolated from patients with PAD and a control group. The effects of specific miRNAs on angiogenesis were evaluated by assessing the in vitro angiogenic function of endothelial progenitor cells (EPCs), performing an in vivo angiogenesis assay, and employing a mouse hindlimb ischemic model. Our results demonstrated that circulating miR-548j-5p was significantly reduced in patients with PAD as compared with the controls. miR-548j-5p promoted EPC angiogenesis by enhancing migration and tube formation. The endothelial nitric oxide synthase (NOS) and stromal cell-derived factor (SDF)-1 signaling pathways appeared to be potential targets of miR-548j-5p. Furthermore, the results of a directed in vivo angiogenesis assay of EPCs and a hindlimb ischemia mouse model demonstrated that miR-548j-5p enhanced the capillary density and blood flow recovery in hindlimb ischemia. In conclusion, our data indicated that up-regulation of miR-548j-5p promotes angiogenesis in ischemic tissue and may represent a novel therapeutic approach for PAD.

HMGA2 contributes to vascular development and sprouting angiogenesis by promoting IGFBP2 production

Angiogenesis is the process by which new blood vessels form from preexisting vessels and regulates the processes of embryonic development, wound healing and tumorigenesis. HMGA2 is involved in the occurrence of several cancers, but its biological role and the exact downstream genes involved in vascular development and sprouting angiogenesis remain largely unknown. Here, we first found that HMGA2 knockdown in zebrafish embryos resulted in defects of central artery formation. RNA sequencing revealed that IGFBP2 was significantly downregulated by interference with HMGA2, and IGFBP2 overexpression reversed the inhibition of brain vascular development caused by HMGA2 deficiency. In vitro, we further found that HMGA2 knockdown blocked the migration, tube formation and branching of HUVECs. Similarly, IGFBP2 protein overexpression attenuated the impairments induced by HMGA2 deficiency. Moreover, the promotion of angiogenesis by HMGA2 overexpression was verified in a Matrigel plug assay. We next found that HMGA2 bound directly to a region in the IGFBP2 promoter and positively regulated IGFBP2 expression. Interestingly, the mRNA expression levels of HMGA2 and IGFBP2 were increased significantly in the peripheral blood of hemangioma patients, indicating that overexpression of HMGA2 and IGFBP2 results in vessel formation, consistent with the results of the in vivo and in vitro experiments. In summary, our findings demonstrate that HMGA2 promotes central artery formation by modulating angiogenesis via IGFBP2 induction.

Involvement of miR-199a-3p/DDR1 in vascular endothelial cell senescence in diabetes

Endothelial cell dysfunction is a prominent feature of diabetic cardiovascular complications, and endothelial cell senescence is considered to be an important contributor to endothelial dysfunction. Discoidin domain receptor 1 (DDR1) has been reported to be involved in atherogenesis and cerebral ischemia/reperfusion injury. In this study, we aimed to explore the role of DDR1 in endothelial cell senescence under diabetic conditions and elucidate the underlying mechanisms. A diabetic rat model was established by a single intraperitoneal injection of streptozocin (STZ) (60 mg/kg), which showed an increase in senescence-associated β-galactosidase (SA-β-gal) staining signal of thoracic aortic endothelium, impaired vascular structure and function, accompanied by an up-regulation of DDR1. Next, we verified the role of DDR1 in endothelial senescence and the underlying mechanisms in high glucose-treated human umbilical vein endothelial cells (HUVECs). Consistent with the in vivo findings, high glucose induced endothelial senescence, impaired endothelial function and elevated DDR1 expression, accompanied by the elevation of senescence-related genes p53 and p21 expression, and these effects were reversed by DDR1 siRNA. DDR1 has been documented to be a potential target of miR-199a-3p. Here, we found that miR-199a-3p was down-regulated by high glucose in the aorta tissue and HUVECs, while miR-199a-3p mimic significantly suppressed increased endothelial senescence and elevated DDR1 induced by high glucose. In conclusion, our data demonstrated that miR-199a-3p/DDR1/p53/p21 signaling pathway was involved in endothelial senescence under diabetic conditions, and therapeutic targeting DDR1 would be exploited to inhibit endothelial senescence owing to high glucose exposure.

Single-cell transcriptomic profiling and characterization of endothelial progenitor cells: new approach for finding novel markers

Background

Endothelial progenitor cells (EPCs) are promising candidates for the cellular therapy of peripheral arterial and cardiovascular diseases. However, hitherto there is no specific marker(s) defining precisely EPCs. Herein, we are proposing a new in silico approach for finding novel EPC markers.

Methods

We assembled five groups of chosen EPC-related genes/factors using PubMed literature and Gene Ontology databases. This shortened database of EPC factors was fed into publically published transcriptome matrix to compare their expression between endothelial colony-forming cells (ECFCs), HUVECs, and two adult endothelial cell types (ECs) from the skin and adipose tissue. Further, the database was used for functional enrichment on Mouse Phenotype database and protein-protein interaction network analyses. Moreover, we built a digital matrix of healthy donors’ PBMCs (33 thousand single-cell transcriptomes) and analyzed the expression of these EPC factors.

Results

Transcriptome analyses showed that BMP2, 4, and ephrinB2 were exclusively highly expressed in EPCs; the expression of neuropilin-1 and VEGF-C were significantly higher in EPCs and HUVECs compared with other ECs; Notch 1 was highly expressed in EPCs and skin-ECs; MIR21 was highly expressed in skin-ECs; PECAM-1 was significantly higher in EPCs and adipose ECs. Moreover, functional enrichment of EPC-related genes on Mouse Phenotype and STRING protein database has revealed significant relations between chosen EPC factors and endothelial and vascular functions, development, and morphogenesis, where ephrinB2, BMP2, and BMP4 were highly expressed in EPCs and were connected to abnormal vascular functions. Single-cell RNA-sequencing analyses have revealed that among the EPC-regulated markers in transcriptome analyses, (i) ICAM1 and Endoglin were weekly expressed in the monocyte compartment of the peripheral blood; (ii) CD163 and CD36 were highly expressed in the CD14+ monocyte compartment whereas CSF1R was highly expressed in the CD16+ monocyte compartment, (iii) L-selectin and IL6R were globally expressed in the lymphoid/myeloid compartments, and (iv) interestingly, PLAUR/UPAR and NOTCH2 were highly expressed in both CD14+ and CD16+ monocytic compartments.

Conclusions

The current study has identified novel EPC markers that could be used for better characterization of EPC subpopulation in adult peripheral blood and subsequent usage of EPCs for various cell therapy and regenerative medicine applications.

HMGA2 as a Critical Regulator in Cancer Development

The high mobility group protein 2 (HMGA2) regulates gene expression by binding to AT-rich regions of DNA. Akin to other DNA architectural proteins, HMGA2 is highly expressed in embryonic stem cells during embryogenesis, while its expression is more limited at later stages of development and in adulthood. Importantly, HMGA2 is re-expressed in nearly all human malignancies, where it promotes tumorigenesis by multiple mechanisms. HMGA2 increases cancer cell proliferation by promoting cell cycle entry and inhibition of apoptosis. In addition, HMGA2 influences different DNA repair mechanisms and promotes epithelial-to-mesenchymal transition by activating signaling via the MAPK/ERK, TGFβ/Smad, PI3K/AKT/mTOR, NFkB, and STAT3 pathways. Moreover, HMGA2 supports a cancer stem cell phenotype and renders cancer cells resistant to chemotherapeutic agents. In this review, we discuss these oncogenic roles of HMGA2 in different types of cancers and propose that HMGA2 may be used for cancer diagnostic, prognostic, and therapeutic purposes.

MicroRNA-205 mediates endothelial progenitor functions in distraction osteogenesis by targeting the transcription regulator NOTCH2

Background

Distraction osteogenesis (DO) is a highly efficacious form of reconstructive bone regeneration, but its clinical utility is limited by the prolonged period required for bone consolidation to occur. Understanding the mechanistic basis for DO and shortening this consolidation phase thus represent promising approaches to improving the clinical utility of this procedure.

Methods

A mandibular DO (MDO) canine model was established, after which small RNA sequencing was performed to identify relevant molecular targets genes. Putative miRNA target genes were identified through bioinformatics and confirmed through qPCR, Western blotting, and dual-luciferase reporter assays. Peripheral blood samples were collected to isolate serum and endothelial colony-forming cells (ECFCs) in order to measure miR-205, NOTCH2, and angiogenic cytokines expression levels. Lentiviral constructs were then used to inhibit or overexpress miR-205 and NOTCH2 in isolated ECFCs, after which the angiogenic activity of these cells was evaluated in migration, wound healing, proliferation, tube formation, and chick chorioallantoic membrane (CAM) assay. Autologous ECFCs transfected to knockdown miR-205 and were injected directly into the distraction callus. On days 14, 28, 35 and 42 after surgery, bone density was evaluated via CBCT, and callus samples were collected and evaluated via histological staining to analyze bone regeneration and remodeling.

Results

MiR-205 was identified as being one of the miRNAs that was most significantly downregulated in MDO callus samples. Downregulation of miR-205 was also observed in DO-ECFCs and serum of animals undergoing MDO. Inhibiting miR-205 markedly enhanced angiogenesis, whereas overexpressing miR-205 had the opposite effect in vitro. Importantly, NOTCH2, which is a unique regulator in bone angiogenesis, was identified as a miR-205 target gene. Consistent with this regulatory relationship, knocking down NOTCH2 suppressed angiogenesis, and transduction with a miR-205 inhibitor lentivirus was sufficient to rescue angiogenic activity. When ECFCs in which miR-205 had been inhibited were transplanted into the MDO callus, this significantly bolstered osteogenesis, and remodeling in vivo.

Conclusions

MiR-205 is a significant regulator of the MDO process, and inhibiting this miRNA can accelerate MDO-related mineralization. Overall, these results offer new insights into the mechanistic basis for this procedure, highlighting potential targets for therapeutic clinical intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02150-x.

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.

Effects of Exercise Training on the Paracrine Function of Circulating Angiogenic Cells

Exercise training has various benefits on cardiovascular health, and circulating angiogenic cells have been proposed as executing these changes. Work from the late 1990s supported an important role of these circulating post-natal cells in contributing to the maintenance and repair of the endothelium and vasculature. It was later found that circulating angiogenic cells were a heterogenous population of cells and primarily functioned in a paracrine manner by adhering to damaged endothelium and releasing growth factors. Many studies have discovered novel circulating angiogenic cell secreted proteins, microRNA and extracellular vesicles that mediate their angiogenic potential, and some studies have shown that both acute and chronic aerobic exercise training have distinct benefits. This review highlights work establishing an essential role of secreted factors from circulating angiogenic cells and summarizes studies regarding the effects of exercise training on these factors. Finally, we highlight the various gaps in the literature in hopes of guiding future work.

Rejuvenation of Senescent Endothelial Progenitor Cells by Extracellular Vesicles Derived From Mesenchymal Stromal Cells

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EVs derived from young, but not aged, MSCs rejuvenate senescent EPCs in vitro, recapitulating the effect of MSC transplantation.

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Aged MSCs can be genetically modified to produce tailored EVs with increased EPC rejuvenation capacity in vitro and increased angiogenesis capacity following ischemic event in vivo.

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EVs represent a promising platform to develop an acellular therapeutic approach in regenerative medicine for cardiovascular diseases.

Mesenchymal stromal cell (MSC) transplantation is a form of the stem-cell therapy that has shown beneficial effects for many diseases. The use of stem-cell therapy, including MSC transplantation, however, has limitations such as the tumorigenic potential of stem cells and the lack of efficacy of aged autologous cells. An ideal therapeutic approach would keep the beneficial effects of MSC transplantation while circumventing the limitations associated with the use of intact stem cells. This study provides proof-of-concept evidence that MSC-derived extracellular vesicles represent a promising platform to develop an acellular therapeutic approach that would just do that. Extracellular vesicles are membranous vesicles secreted by MSCs and contain bioactive molecules to mediate communication between different cells. Extracellular vesicles can be taken up by recipient cells, and once inside the recipient cells, the bioactive molecules are released to exert the beneficial effects on the recipient cells. This study, for the first time to our knowledge, shows that extracellular vesicles secreted by MSCs recapitulate the beneficial effects of MSCs on vascular repair and promote blood vessel regeneration after ischemic events. Furthermore, MSCs from aged donors can be engineered to produce extracellular vesicles with improved regenerative potential, comparable to MSCs from young donors, thus eliminating the need for allogenic young donors for elderly patients.

HMGA2-mediated tumorigenesis through angiogenesis in leiomyoma

OBJECTIVE

To study the role of HMGA2 in promoting angiogenesis in uterine leiomyoma (LM).

DESIGN

This study involved evaluation of vessel density and angiogenic factors in leiomyomas with HMGA2 overexpression; examining angiogenic factor expression and AKT signaling in myometrial (MM) and leiomyoma cells by introducing HMGA2 overexpression in vitro; and exploring vessel formation induced by HMGA2 overexpression both in vitro and in vivo.

SETTING

University research laboratory.

PATIENTS

None.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

The main outcome measures include vessel density in leiomyomas with HMGA2 (HMGA2-LM) or MED12 (MED12-LM) alteration; angiogenic factor expression in primary leiomyoma and in vitro cell line model; and vessel formation in leiomyoma cells with HMGA2 overexpression in vitro and in vivo.

RESULTS

Angiogenic factors and receptors were significantly upregulated at mRNA and protein levels in HMGA2-LM. Specifically, HMGA2-LM exhibited increased expression of VEGFA, EGF, bFGF, TGFα, VEGFR1, and VEGFR2 compared to MED12-LM and myometrium. Overexpression of HMGA2 in MM and LM cell lines resulted in increased secretion of angiogenesis-associated factors. Secreted factors promoted human umbilical vein endothelial cell (HUVEC) migration, tube formation, and wound healing. HMGA2 overexpression upregulated IGF2BP2 and pAKT, and silencing the IGF2BP2 gene reduced pAKT levels and reduced HUVEC migration. Myometrial cells with stable HMGA2 overexpression exhibited increased colony formation and cell growth in vitro and formed xenografts with increased blood vessels.

CONCLUSIONS

HMGA2-LM have a high vasculature density, which likely contributes to tumor growth and disease burden of this leiomyoma subtype. HMGA2 plays an important role in angiogenesis and the involvement of IGF2BP2-mediated pAKT activity in angiogenesis, which provides a potential novel target for therapy for this subtype of LM.

Vascular ageing in hypertension: Focus on mitochondria

Hypertension is a common age-related disease, along with vascular and neurodegenerative diseases. Vascular ageing increases during hypertension, but hypertension itself accelerates vascular ageing, thus creating a vicious circle. Vascular stiffening, endothelial dysfunction, impaired contractility and vasorelaxation are the main alterations related to vascular ageing, as a consequence of vascular smooth muscle and endothelial cells senescence. Several molecular mechanisms have been involved into the functional and morphological changes of the aged vessels. Among them, oxidative stress, inflammation, extracellular matrix deregulation and mitochondrial dysfunction are the best characterized. In the present review, we discuss relevant literature about the biology of vascular and cerebrovascular ageing with a particular focus on mitochondria signalling. We underline the therapeutic strategies, able to improve mitochondrial health, which may represent a promising tool to decrease vascular dysfunction associated with ageing and hypertension-related complications.

Meta-Analysis of the Potential Role of miRNA-21 in Cardiovascular System Function Monitoring

MicroRNAs (miRNAs) are short and noncoding RNA fragments that bind to the messenger RNA. They have different roles in many physiological or pathological processes. MicroRNA-21, one of the first miRNAs discovered, is encoded by the MIR21 gene and is located on the chromosomal positive strand 17q23.2. MicroRNA-21 is transcribed by polymerase II and has its own promoter sequence, although it is in an intron. It is intra- and extracellular and can be found in many body fluids, alone or combined with another molecule. It regulates many signalling pathways and therefore plays an important role in the cardiovascular system. Indeed, it is involved in the differentiation and migration of endothelial cells and angiogenesis. It contributes to the reconstruction of a myocardial infarction, and it can also act as a cellular connector or as an antagonist to cardiac cell apoptosis. By playing all these roles, it can be interesting to use it as a biomarker, especially for cardiovascular diseases.

Small extracellular vesicles deliver miR-21 and miR-217 as pro-senescence effectors to endothelial cells

The role of epigenetics in endothelial cell senescence is a cutting-edge topic in ageing research. However, little is known of the relative contribution to pro-senescence signal propagation provided by microRNAs shuttled by extracellular vesicles (EVs) released from senescent cells. Analysis of microRNA and DNA methylation profiles in non-senescent (control) and senescent (SEN) human umbilical vein endothelial cells (HUVECs), and microRNA profiling of their cognate small EVs (sEVs) and large EVs demonstrated that SEN cells released a significantly greater sEV number than control cells. sEVs were enriched in miR-21-5p and miR-217, which target DNMT1 and SIRT1. Treatment of control cells with SEN sEVs induced a miR-21/miR-217-related impairment of DNMT1-SIRT1 expression, the reduction of proliferation markers, the acquisition of a senescent phenotype and a partial demethylation of the locus encoding for miR-21. MicroRNA profiling of sEVs from plasma of healthy subjects aged 40-100 years showed an inverse U-shaped age-related trend for miR-21-5p, consistent with senescence-associated biomarker profiles. Our findings suggest that miR-21-5p/miR-217 carried by SEN sEVs spread pro-senescence signals, affecting DNA methylation and cell replication.

High Mobility Group A (HMGA): Chromatin Nodes Controlled by a Knotty miRNA Network

High mobility group A (HMGA) proteins are oncofoetal chromatin architectural factors that are widely involved in regulating gene expression. These proteins are unique, because they are highly expressed in embryonic and cancer cells, where they play a relevant role in cell proliferation, stemness, and the acquisition of aggressive tumour traits, i.e., motility, invasiveness, and metastatic properties. The HMGA protein expression levels and activities are controlled by a connected set of events at the transcriptional, post-transcriptional, and post-translational levels. In fact, microRNA (miRNA)-mediated RNA stability is the most-studied mechanism of HMGA protein expression modulation. In this review, we contribute to a comprehensive overview of HMGA-targeting miRNAs; we provide detailed information regarding HMGA gene structural organization and a comprehensive evaluation and description of HMGA-targeting miRNAs, while focusing on those that are widely involved in HMGA regulation; and, we aim to offer insights into HMGA-miRNA mutual cross-talk from a functional and cancer-related perspective, highlighting possible clinical implications.

Noncoding RNAs in Vascular Aging

Increases in age are accompanied by vascular aging, which can lead to a variety of chronic diseases, including atherosclerosis and hypertension. Noncoding RNAs (ncRNAs) have become a research hotspot in different fields of life sciences in recent years. For example, these molecules have been found to have regulatory roles in many physiological and pathological processes. Many studies have shown that microRNAs (miRNAs) and long ncRNAs (lncRNAs) also play a regulatory role in vascular aging. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are important components of blood vessels, and the senescence of both cell types promotes the occurrence of vascular aging. This review provides a contemporary update on the molecular mechanisms underlying the senescence of ECs and VSMCs and the regulatory role of miRNAs and lncRNAs in this process.

Noncoding RNAs in Critical Limb Ischemia

Peripheral artery disease, caused by chronic arterial occlusion of the lower extremities, affects over 200 million people worldwide. Peripheral artery disease can progress into critical limb ischemia (CLI), its more severe manifestation, which is associated with higher risk of limb amputation and cardiovascular death. Aiming to improve tissue perfusion, therapeutic angiogenesis held promise to improve ischemic limbs using delivery of growth factors but has not successfully translated into benefits for patients. Moreover, accumulating studies suggest that impaired downstream signaling of these growth factors (or angiogenic resistance) may significantly contribute to CLI, particularly under harsh environments, such as diabetes mellitus. Noncoding RNAs are essential regulators of gene expression that control a range of pathophysiologies relevant to CLI, including angiogenesis/arteriogenesis, hypoxia, inflammation, stem/progenitor cells, and diabetes mellitus. In this review, we summarize the role of noncoding RNAs, including microRNAs and long noncoding RNAs, as functional mediators or biomarkers in the pathophysiology of CLI. A better understanding of these ncRNAs in CLI may provide opportunities for new targets in the prevention, diagnosis, and therapeutic management of this disabling disease state.

Reduced NRF2 expression suppresses endothelial progenitor cell function and induces senescence during aging

Aging is associated with an increased risk of cardiovascular disease. Numerical and functional declines in endothelial progenitor cells (EPCs) limit their capacity for endothelial repair and promote the development of cardiovascular disease. We explored the effects of nuclear factor (erythroid-derived 2)-like 2 (NRF2) on EPC activity during aging. Both in vitro and in vivo, the biological functioning of EPCs decreased with aging. The expression of NRF2 and its target genes (Ho-1, Nqo-1 and Trx) also declined with aging, while Nod-like receptor protein 3 (NLRP3) expression increased. Aging was associated with oxidative stress, as evidenced by increased reactive oxygen species and malondialdehyde levels and reduced superoxide dismutase activity. Nrf2 silencing impaired the functioning of EPCs and induced oxidative stress in EPCs from young mice. On the other hand, NRF2 activation in EPCs from aged mice protected these cells against oxidative stress, ameliorated their biological dysfunction and downregulated the NLRP3 inflammasome. These findings suggest NRF2 can prevent the functional damage of EPCs and downregulate the NLRP3 inflammasome through NF-κB signaling.

Oncological role of HMGA2 (Review)

The high mobility group A2 (HMGA2) protein is a non‑histone architectural transcription factor that modulates the transcription of several genes by binding to AT‑rich sequences in the minor groove of B‑form DNA and alters the chromatin structure. As a result, HMGA2 influences a variety of biological processes, including the cell cycle process, DNA damage repair process, apoptosis, senescence, epithelial‑mesenchymal transition and telomere restoration. In addition, the overexpression of HMGA2 is a feature of malignancy, and its elevated expression in human cancer predicts the efficacy of certain chemotherapeutic agents. Accumulating evidence has suggested that the detection of HMGA2 can be used as a routine procedure in clinical tumour analysis.

HMGA2 Contributes to Distant Metastasis and Poor Prognosis by Promoting Angiogenesis in Oral Squamous Cell Carcinoma

The highly malignant phenotype of oral squamous cell carcinoma (OSCC), including the presence of nodal and distant metastasis, reduces patient survival. High-mobility group A protein 2 (HMGA2) is a non-histone chromatin factor that is involved in advanced malignant phenotypes and poor prognosis in several human cancers. However, its biological role in OSCC remains to be elucidated. The purpose of this study was to determine the clinical significance and role of HMGA2 in the malignant potential of OSCC. We first investigated the expression pattern of HMGA2 and its clinical relevance in 110 OSCC specimens using immunohistochemical staining. In addition, we examined the effects HMGA2 on the regulation of vascular endothelial growth factor (VEGF)-A, VEGF-C, and fibroblast growth factor (FGF)-2, which are related to angiogenesis, in vitro. High expression of HMGA2 was significantly correlated with distant metastasis and poor prognosis. Further, HMGA2 depletion in OSCC cells reduced the expression of angiogenesis genes. In OSCC tissues with high HMGA2 expression, angiogenesis genes were increased and a high proportion of blood vessels was observed. These findings suggest that HMGA2 plays a significant role in the regulation of angiogenesis and might be a potential biomarker to predict distant metastasis and prognosis in OSCC.

lncRNA GAS5/miR-223/NAMPT axis modulates the cell proliferation and senescence of endothelial progenitor cells through PI3K/AKT signaling

Endothelial progenitor cells (EPCs) have been reported to replace the damaged endothelial cells to repair the injured or dead endothelium. However, EPC senescence might lead to the failure in EPC function. Thus, developing an in-depth understanding of the mechanism of EPC senescence might provide novel strategies for related vascular disorders' treatments. Herein, nicotinamide phosphoribosyltransferase (NAMPT) overexpression could increase cell proliferation and suppress cell senescence in EPCs. miR-223 directly bound to the 3'-untranslated region of NAMPT to inhibit its expression, therefore modulating EPC proliferation and senescence through NAMPT and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling. Long noncoding RNA (lncRNA) GAS5 sponges miR-223, consequently downregulating miR-223 expression. GAS5 knockdown inhibited EPC proliferation and promoted senescence. GAS5 might serve as a competing endogenous RNA for miR-223 to counteract miR-223-mediated suppression on NAMPT, thus regulating EPC proliferation and senescence via the PI3K/AKT signaling pathway. In summary, our findings provide a solid experimental basis for understanding the role and mechanism of lncRNA GAS5/miR-223/NAMPT axis in EPC proliferation and senescence.

Platelets of Healthy Origins Promote Functional Improvement of Atherosclerotic Endothelial Progenitor Cells

The purpose was to evaluate the effect of platelets on functional properties of late endothelial progenitor cells (EPCs), in the direct co-culture conditions, and to investigate the involved mediators, in experimental induced atherosclerosis. The late EPCs obtained from two animal groups, hypertensive-hyperlipidemic (HH) and control (C) hamsters, named late EPCs-HH and late EPCs-C, were co-incubated with or without platelets isolated from both groups. Our results have showed that exposure to platelets from control animals: (i) promoted the late EPCs-C capacity to form colonies and capillary-like structures, and also to proliferate and migrate; (ii) improved the functional properties of late EPCs-HH; (iii) strengthened the direct binding EPCs-platelets; (iv) increased SDF-1α,VEGF, PDGF, and reduced CD40L, IL-1β,-6,-8 levels; and (v) enhanced miR-223 and IGF-1R expressions. Platelets from HH group diminished functional abilities for both EPC types and had opposite effects on these pro-angiogenic and pro-inflammatory molecules. Furthermore, testing the direct effect of miR-223 and IGF-1R on late EPCs disclosed that these molecular factors improve late EPC functional properties in atherosclerosis in terms of stimulation of the proliferation and migration abilities. In conclusion, in vitro exposure to platelets of healthy origins had a positive effect on functional properties of atherosclerotic late EPCs. The most likely candidates mediating EPC-platelet interaction can be SDF-1α, VEGF, CD40L, PDGF, IL-1β,-6,-8, miR-223, and IGF-1R. The current study brings evidences that the presence of healthy origin platelets is of utmost importance on functional improvement of EPCs in atherosclerosis.

Micrornas at the Interface between Osteogenesis and Angiogenesis as Targets for Bone Regeneration

Bone formation and regeneration is a multistep complex process crucially determined by the formation of blood vessels in the growth plate region. This is preceded by the expression of growth factors, notably the vascular endothelial growth factor (VEGF), secreted by osteogenic cells, as well as the corresponding response of endothelial cells, although the exact mechanisms remain to be clarified. Thereby, coordinated coupling between osteogenesis and angiogenesis is initiated and sustained. The precise interplay of these two fundamental processes is crucial during times of rapid bone growth or fracture repair in adults. Deviations in this balance might lead to pathologic conditions such as osteoarthritis and ectopic bone formation. Besides VEGF, the recently discovered important regulatory and modifying functions of microRNAs also support this key mechanism. These comprise two principal categories of microRNAs that were identified with specific functions in bone formation (osteomiRs) and/or angiogenesis (angiomiRs). However, as hypoxia is a major driving force behind bone angiogenesis, a third group involved in this process is represented by hypoxia-inducible microRNAs (hypoxamiRs). This review was focused on the identification of microRNAs that were found to have an active role in osteogenesis as well as angiogenesis to date that were termed "CouplingmiRs (CPLGmiRs)". Outlined representatives therefore represent microRNAs that already have been associated with an active role in osteogenic-angiogenic coupling or are presumed to have its potential. Elucidation of the molecular mechanisms governing bone angiogenesis are of great relevance for improving therapeutic options in bone regeneration, tissue-engineering, and the treatment of bone-related diseases.

Substantial Dysregulation of miRNA Passenger Strands Underlies the Vascular Response to Injury

Vascular smooth muscle cell (VSMC) dedifferentiation is a common feature of vascular disorders leading to pro-migratory and proliferative phenotypes, a process induced through growth factor and cytokine signaling cascades. Recently, many studies have demonstrated that small non-coding RNAs (miRNAs) can induce phenotypic effects on VSMCs in response to vessel injury. However, most studies have focused on the contribution of individual miRNAs. Our study aimed to conduct a detailed and unbiased analysis of both guide and passenger miRNA expression in vascular cells in vitro and disease models in vivo. We analyzed 100 miRNA stem loops by TaqMan Low Density Array (TLDA) from primary VSMCs in vitro. Intriguingly, we found that a larger proportion of the passenger strands was significantly dysregulated compared to the guide strands after exposure to pathological stimuli, such as platelet-derived growth factor (PDGF) and IL-1α. Similar findings were observed in response to injury in porcine vein grafts and stent models in vivo. In these studies, we reveal that the miRNA passenger strands are predominantly dysregulated in response to vascular injury.

The Emerging Roles of microRNAs in Stem Cell Aging

Aging is the continuous loss of tissue and organ function over time. MicroRNAs (miRNAs) are thought to play a vital role in this process. miRNAs are endogenous small noncoding RNAs that control the expression of target mRNA. They are involved in many biological processes such as developmental timing, differentiation, cell death, stem cell proliferation and differentiation, immune response, aging and cancer. Accumulating studies in recent years suggest that miRNAs play crucial roles in stem cell division and differentiation. In the present chapter, we present a brief overview of these studies and discuss their contributions toward our understanding of the importance of miRNAs in normal and aged stem cell function in various model systems.

Anti-Angiogenic miR-222, miR-195, and miR-21a Plasma Levels in T1DM Are Improved by Metformin Therapy, Thus Elucidating Its Cardioprotective Effect: The MERIT Study

Type 1 diabetes (T1DM) is associated with increased cardiovascular disease (CVD) and reduced life expectancy. We thus hypothesized that anti-angiogenic miRs are increased in T1DM, and the cardioprotective effect of metformin is mediated via reducing those miRs. In an open label, case-controlled study, 23 T1DM patients without CVD were treated with metformin for eight weeks (TG), matched with nine T1DM patients on standard treatment (SG) and 23 controls (CG). Plasma miR-222, miR-195, miR-21a and miR-126 were assayed by real-time RT-qPCR. The results were correlated with: endothelial function (RHI), circulating endothelial progenitor cells (cEPCs) (vascular repair marker, CD45^dimCD34⁺VEGFR2⁺ cells) and circulating endothelial cells (cECs) (vascular injury marker, CD45^dimCD34⁺CD133^-CD144⁺ cells). miR-222, miR-195 and miR-21a were higher in T1DM than CG; p = 0.009, p < 0.0001, p = 0.0001, respectively. There was an inverse correlation between logmiR-222 and logRHI (p < 0.05) and a direct correlation between logmiR-222 and logCD34⁺ (p < 0.05) in TG. Metformin reduced miR-222, miR-195 and miR-21a levels in TG; p = 0.007, p = 0.002 p = 0.0012, respectively. miRs remained unchanged in SG. miR-126 was similar in all groups. There was a positive association between changes in logmiR-222 and logcECs after metformin in TG (p < 0.05). Anti-angiogenic miRs are increased in T1DM. Metformin has cardioprotective effects through downregulating miR-222, miR-195 and miR-21a, beyond improving glycemic control.

Sonic Hedgehog Signaling Pathway in Endothelial Progenitor Cell Biology for Vascular Medicine

The Hedgehog (HH) signaling pathway plays an important role in embryonic and postnatal vascular development and in maintaining the homeostasis of organs. Under physiological conditions, Sonic Hedgehog (SHH), a secreted protein belonging to the HH family, regulates endothelial cell growth, promotes cell migration and stimulates the formation of new blood vessels. The present review highlights recent advances made in the field of SHH signaling in endothelial progenitor cells (EPCs). The canonical and non-canonical SHH signaling pathways in EPCs and endothelial cells (ECs) related to homeostasis, SHH signal transmission by extracellular vesicles (EVs) or exosomes containing single-strand non-coding miRNAs and impaired SHH signaling in cardiovascular diseases are discussed. As a promising therapeutic tool, the possibility of using the SHH signaling pathway for the activation of EPCs in patients suffering from cardiovascular diseases is further explored.

Stem cell properties of peripheral blood endothelial progenitors are stimulated by soluble CD146 via miR-21: potential use in autologous cell therapy

Cell-based therapies constitute a real hope for the treatment of ischaemic diseases. One of the sources of endothelial progenitors for autologous cell therapy is Endothelial Colony Forming Cells (ECFC) that can be isolated from peripheral blood. However, their use is limited by their low number in the bloodstream and the loss of their stem cell phenotype associated with the acquisition of a senescent phenotype in culture. We hypothesized that adding soluble CD146, a novel endothelial growth factor with angiogenic properties, during the isolation and growth procedures could improve their number and therapeutic potential. Soluble CD146 increased the number of isolated peripheral blood ECFC colonies and lowered their onset time. It prevented cellular senescence, induced a partial mesenchymal phenotype and maintained a stem cell phenotype by stimulating the expression of embryonic transcription factors. These different effects were mediated through the induction of mature miR-21. When injected in an animal model of hindlimb ischaemia, sCD146-primed ECFC isolated from 40 ml of blood from patients with peripheral arterial disease were able to generate new blood vessels and restore blood flow. Treatment with sCD146 could thus constitute a promising strategy to improve the use of autologous cells for the treatment of ischaemic diseases.

Mini-Review: Assessing the Potential Impact of Microneedle Technologies on Home Healthcare Applications

The increasing devolution of healthcare towards community care has meant that the management of many conditions is conducted within the home either by community nurses or by the patients themselves. The administration of medicines within home healthcare scenarios can however be problematic—especially when considering the delivery of medicines through injection. The possibility of needlestick injury (NSI) has become an ever-present hazard within healthcare settings, with a significant proportion of percutaneous injuries occurring during the handling and disposal of the needle. The emergence of transdermal microneedle systems, however, offers a potentially revolutionary advance and could dramatically improve safety—particularly within home healthcare where there are mounting concerns over the use and disposal of sharps. A mini-review of the advantages proffered by microneedle drug delivery technologies is presented and the potential impact on delivery of medicines within the home is critically appraised.