Extracellular vesicles from early- and late-passage endothelial cells differentially regulate cerebrovascular and brain aging in mice via changes in a miR-17-5p-dependent pathway
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ABSTRACT: Vascular aging, which is characterized by brain endothelial cell (EC) senescence and dysfunction, is known to contribute to various age-related cerebrovascular and neurodegenerative diseases. However, the underlying mechanisms remain unclear. EC-derived microvesicles (EMVs) and exosomes (EEXs) retain the characteristics of parent cells and transfer their contents to modulate the functions of recipient cells, showing potential for evaluation or regulation of vascular aging. Here, as indicated by analyses of senescence-associated beta-galactosidase (SA-β-gal) staining, cerebral blood flow, blood–brain barrier function, aging-related markers and cognitive ability, we found that young primary EC (passage 2-4) released EMVs alleviated mouse cerebrovascular and brain aging more effectively than EEXs. Aged EC (passage 15-16) released EMVs were more effective than their released EEXs at exacerbating mouse cerebrovascular and brain aging. We further revealed that these EMVs regulated cerebrovascular and brain aging by transferring miR-17-5p and modulated EC senescence and function via the miR-17-5p/PI3K/Akt pathway. Clinically, the levels of plasma EMVs and their associated miR-17-5p (EMV-miR-17-5p) were significantly increased or decreased in elderly individuals and were closely correlated with reactive oxygen species (ROS) and vascular aging. Receiver operating characteristic (ROC) analysis revealed that the area under the curve (AUC) was 0.724 for EMVs, 0.77 for EMV-miR-17-5p and 0.815 for their combination for distinguishing vascular aging. Our results identified novel roles for EMVs and showed that these vesicles more effectively modulated vascular and brain aging than did EEXs by regulating EC functions through the miR-17-5p/PI3K/Akt pathway; thus, EMVs and EMV-miR-17-5p are promising biomarkers and therapeutic targets for vascular aging.
Project description:Dysfunction of vascular endothelium is characteristic of many aging-related diseases, including Alzheimers disease (AD) and AD-related dementias (ADRD). While it is widely posited that endothelial cell dysfunction contributes to the pathogenesis and/or progression of AD/ADRD, it is not clear how. A plausible hypothesis is that intercellular trafficking of extracellular vesicles (EVs) from senescent vascular endothelial cells promotes vascular endothelial cell dysfunction. To test this hypothesis, we compared the expression of proteins and miRNAs in EVs isolated from early passage (EP) vs. senescent (SEN) primary human coronary artery endothelial cells (HCAECs) from the same donor. Proteomics and miRNA libraries constructed from these EV isolates were evaluated using FunRich gene ontology analysis to compare functional enrichment between EP and SEN endothelial cell EVs (ECEVs). Replicative senescence was associated with altered EV abundance and contents independent of changes in EV size. Unique sets of miRNAs and proteins were differentially expressed in SEN-ECEVs, including molecules related to cell adhesion, barrier integrity, receptor signaling, endothelial-mesenchymal transition and cell senescence. miR-181a-5p was the most upregulated miRNA in SEN-ECEVs, increasing >5-fold. SEN-ECEV proteomes supported involvement in several pro-inflammatory pathways consistent with senescence and the senescence-associated secretory phenotype (SASP). These data indicate that SEN-ECEVs are enriched in bioactive molecules implicated in senescence-associated vascular dysfunction, blood-brain barrier impairment, and AD/ADRD pathology. These observations suggest involvement of SEN-ECEVs in the pathogenesis of vascular dysfunction associated with AD/ADRD.
Project description:The mechanism by which aging induces aortic aneurysm and dissection (AAD) remains unclear. A total of 430 subjects were recruited for screening of differentially expressed plasma microRNAs. We found that miR-1204 was significantly increased in both plasma and aorta of elder patients with AAD, and was positively correlated with age. Cell senescence induced the expression of miR-1204 through p53 interaction with plasmacytoma variant translocation 1, and miR-1204 induced vascular smooth muscle cell (VSMC) senescence to form a positive feedback loop. miR-1204 aggravated angiotensin II-induced AAD formation, and inhibition of miR-1204 attenuated β-aminopropionitrile monofumarate-induced AAD formation. Mechanistically, miR-1204 directly targeted myosin light chain kinase (MYLK) to promote VSMCs to acquire senescence-associated secretory phenotype (SASP) and lose their contractile phenotype. Overexpression of MYLK reversed miR-1204-induced VSMC senescence, SASP and contractile phenotype changes, and the decrease of transforming growth factor-β signaling pathway. Our findings suggest aging aggravates AAD via miR-1204-MYLK signaling axis.
Project description:One of the cellular processes influenced by microRNAs is senescence, a state of indefinite growth arrest triggered by sublethal cell damage. Here, through bioinformatic analysis and experimental validation, we identified miR-340-5p as a novel miRNA that foments cellular senescence. miR340-5p was highly abundant in diverse senescence models, and miR-340-5p overexpression in proliferating cells rendered them senescent. Among the target mRNAs, miR-340-5p prominently reduced the levels of LBR mRNA, encoding Lamin B Receptor (LBR). Loss of LBR by ectopic overexpression of miR-340-5p derepressed heterochromatin in lamina-associated domains (LADs), promoting the expression of DNA repetitive elements characteristic of senescence. Importantly, overexpressing miR-340-5p enhanced cellular sensitivity to senolytic compounds, while antagonization of miR-340-5p reduced senescent-cell markers and engendered resistance to senolytic-induced cell death. We propose that miR-340-5p can be exploited for clearing senescent cells to restore tissue homeostasis and mitigate damage by senescent cells in aging human pathologies.
Project description:One of the cellular processes influenced by microRNAs is senescence, a state of indefinite growth arrest triggered by sublethal cell damage. Here, through bioinformatic analysis and experimental validation, we identified miR-340-5p as a novel miRNA that foments cellular senescence. miR340-5p was highly abundant in diverse senescence models, and miR-340-5p overexpression in proliferating cells rendered them senescent. Among the target mRNAs, miR-340-5p prominently reduced the levels of LBR mRNA, encoding Lamin B Receptor (LBR). Loss of LBR by ectopic overexpression of miR-340-5p derepressed heterochromatin in lamina-associated domains (LADs), promoting the expression of DNA repetitive elements characteristic of senescence. Importantly, overexpressing miR-340-5p enhanced cellular sensitivity to senolytic compounds, while antagonization of miR-340-5p reduced senescent-cell markers and engendered resistance to senolytic-induced cell death. We propose that miR-340-5p can be exploited for clearing senescent cells to restore tissue homeostasis and mitigate damage by senescent cells in aging human pathologies.
Project description:An in-depth understanding of the molecular processes composing aging is crucial to develop therapeutic approaches that decrease aging as a key risk factor for cognitive decline. Herein, we present a spatio-temporal brain atlas (15 different regions) of microRNA expression across the mouse lifespan (7 time points) and two aging interventions. MicroRNAs are promising therapeutic targets, as they silence genes by complementary base-pair binding of messenger RNAs and mediate aging speed. We first established sex- and brain-region-specific microRNA expression patterns in young adult samples. Then we focused on sex-dependent and independent brain-region-specific microRNA expression changes during aging. We identified three sex-independent brain aging microRNAs (miR-146a-5p, miR-155-5p and miR-5100). For miR-155-5p, we showed that these expression changes are driven by aging microglia and target mTOR signaling pathway components and other cellular communication pathways. In this work, we identify strong sex-brain-region-specific aging microRNAs and microglial miR-155-5p as a promising therapeutic target.
Project description:An in-depth understanding of the molecular processes composing aging is crucial to develop therapeutic approaches that decrease aging as a key risk factor for cognitive decline. Herein, we present a spatio-temporal brain atlas (15 different regions) of microRNA expression across the mouse lifespan (7 time points) and two aging interventions. MicroRNAs are promising therapeutic targets, as they silence genes by complementary base-pair binding of messenger RNAs and mediate aging speed. We first established sex- and brain-region-specific microRNA expression patterns in young adult samples. Then we focused on sex-dependent and independent brain-region-specific microRNA expression changes during aging. We identified three sex-independent brain aging microRNAs (miR-146a-5p, miR-155-5p and miR-5100). For miR-155-5p, we showed that these expression changes are driven by aging microglia and target mTOR signaling pathway components and other cellular communication pathways. In this work, we identify strong sex-brain-region-specific aging microRNAs and microglial miR-155-5p as a promising therapeutic target.
Project description:The goal of this study was to identify accessible chromatin peaks in lamina-associated domains of senescent cells. To establish senescence we used ionizing radiation (IR), overexpression of miR-340-5p, and knockdown of Lamin B Receptor (LBR).One of the cellular processes influenced by microRNAs is senescence, a state of indefinite growth arrest triggered by sublethal cell damage. Here, through bioinformatic analysis and experimental validation, we identified miR-340-5p as a novel miRNA that foments cellular senescence. miR340-5p was highly abundant in diverse senescence models, and miR-340-5p overexpression in proliferating cells rendered them senescent. Among the target mRNAs, miR-340-5p prominently reduced the levels of LBR mRNA, encoding Lamin B Receptor (LBR). Loss of LBR by ectopic overexpression of miR-340-5p derepressed heterochromatin in lamina-associated domains (LADs), promoting the expression of DNA repetitive elements characteristic of senescence. Importantly, overexpressing miR-340-5p enhanced cellular sensitivity to senolytic compounds, while antagonization of miR-340-5p reduced senescent-cell markers and engendered resistance to senolytic-induced cell death. We propose that miR-340-5p can be exploited for clearing senescent cells to restore tissue homeostasis and mitigate damage by senescent cells in aging human pathologies.
Project description:Aging significantly affects intercellular communication between vascular endothelial cells (ECs) and hematopoietic cells, leading to vascular inflammation and age-associated diseases. This study determined how senescent ECs communicate with monocytes, whether extracellular vesicles (EVs) released from senescent ECs affect monocyte functions, and investigated the potential for epigallocatechin-3-gallate (EGCG), a flavonoid in green tea, to reverse these effects. Human umbilical vein endothelial cells (HUVECs) were treated with Etoposide (10 µM, 24h) to induce senescence, followed by EGCG (100 µM, 24h) treatment to evaluate its potential as a senotherapeutic agent. The interaction between ECs and monocytes was analyzed using a co-culture system and direct treatment of monocytes with EC-derived EVs. EGCG reduced senescence-associated phenotypes in ECs, as evidenced by decreased senescence-associated (SA)-β-Gal activity and reversal of Etoposide-induced senescence markers. Monocytes co-cultured with EGCG-treated senescent ECs showed decreased pro-inflammatory responses compared to those co-cultured with untreated senescent ECs. Additionally, senescent ECs produced more EVs than non-senescent ECs. EVs from senescent ECs enhanced lipopolysaccharide (LPS)-induced pro-inflammatory activation of monocytes, whereas EVs from EGCG-treated senescent ECs mitigated this activation, maintaining monocyte activation at normal levels. Our findings reveal that EGCG confers anti-senescent effects via modulation of the senescent EC secretome (including EVs) with the capacity to modify monocyte activation. These findings suggest that EGCG could act as a senotherapeutic agent to reduce vascular inflammation related to aging.
Project description:The homeostasis of vascular endothelium is crucial for cardiovascular health and endothelial cell (EC) aging and dysfunction could negatively impact vascular function. Leveraging time-series transcriptomic data obtained from endothelial cells (ECs) subjected to physiological pulsatile flow versus pathophysiological oscillatory flow, we performed principal component analysis (PCA) to identify key genes contributing to divergent transcriptional states of ECs under distinct flow patterns. Through bioinformatics analysis, we identified that a long non-coding RNA (lncRNA) RAMP2- AS1 encoded on the antisense of RAMP2, a determinant of endothelial homeostasis and vascular integrity, is a novel regulator essential for EC homeostasis and function. Knockdown of RAMP2-AS1 inhibited EC angiogenesis and promoted EC senescence, as a result of extensive changes of EC transcriptome. Our study demonstrates an integrative approach to quantifying EC aging based on transcriptome changes, which also identified a number of novel regulators, including protein-coding genes and many lncRNAs involved EC functional modulation.
Project description:The impact of vascular aging (VA) has been extensively studied, yet little is known regarding the cellular and molecular mechanism underlying age-related VA in aortic cellular subpopulations. Herein, we analyzed transcriptomes and transposase-accessible chromatin profiles from aortas of 4-, 26-, and 86-week-old mice using single-cell RNA sequencing and ATAC sequencing. By integrating the heterogeneous transcriptome and chromatin accessibility data, we identified cell-specific transcription factor (TF) regulatory networks and open chromatin states. Moreover, we found that aortic aging affects cell interactions, inflammation, cell type composition and dysregulation of transcriptional control. Endothelial cell (EC) 1 has higher gene set activity related to senescence, aging, and adipogenesis than EC 2. Construction of senescence trajectories showed that the senescence of EC 1 and fibroblasts is associated with distinct TF open chromatin states and an mRNA expression model. Our data provide a system-wide model for transcriptional and epigenetic regulation during aortic aging at single-cell resolution.