Cellular senescence after single and repeated balloon catheter denudations of rabbit carotid arteries

Treating Metabolic Dysregulation and Senescence by Caloric Restriction: Killing Two Birds with One Stone?

Cellular senescence is a state of permanent cell cycle arrest accompanied by metabolic activity and characteristic phenotypic changes. This process is crucial for developing age-related diseases, where excessive calorie intake accelerates metabolic dysfunction and aging. Overnutrition disturbs key metabolic pathways, including insulin/insulin-like growth factor signaling (IIS), the mammalian target of rapamycin (mTOR), and AMP-activated protein kinase. The dysregulation of these pathways contributes to insulin resistance, impaired autophagy, exacerbated oxidative stress, and mitochondrial dysfunction, further enhancing cellular senescence and systemic metabolic derangements. On the other hand, dysfunctional endothelial cells and adipocytes contribute to systemic inflammation, reduced nitric oxide production, and altered lipid metabolism. Numerous factors, including extracellular vesicles, mediate pathological communication between the vascular system and adipose tissue, amplifying metabolic imbalances. Meanwhile, caloric restriction (CR) emerges as a potent intervention to counteract overnutrition effects, improve mitochondrial function, reduce oxidative stress, and restore metabolic balance. CR modulates pathways such as IIS, mTOR, and sirtuins, enhancing glucose and lipid metabolism, reducing inflammation, and promoting autophagy. CR can extend the health span and mitigate age-related diseases by delaying cellular senescence and improving healthy endothelial-adipocyte interactions. This review highlights the crosstalk between endothelial cells and adipocytes, emphasizing CR potential in counteracting overnutrition-induced senescence and restoring vascular homeostasis.

The potential of flavonoids to mitigate cellular senescence in cardiovascular disease

Aging is one of the most significant factors affecting cardiovascular health, with cellular senescence being a central hallmark. Senescent cells (SCs) secrete a specific set of signaling molecules known as the senescence-associated secretory phenotype (SASP). The SASP has a remarkable impact on age-associated diseases, particularly cardiovascular diseases (CVD). Targeting SCs through anti-aging therapies represents a novel strategy to effectively retard senescence and attenuate disease progression. Accumulating evidence demonstrates that the flavonoids, widely presented in fruits and vegetables worldwide, can delay or treat CVD via selectively eliminating SCs (senolytics) and modulating SASPs (senomorphics). Nevertheless, only sporadic research has illustrated the application of flavonoids in targeting SCs for CVD, which requires further exploration. This review recapitulates the hallmarks and key molecular mechanisms involved in cellular senescence, then summarizes senescence of different types of cardiac cells and describes the mechanisms by which cellular senescence affects CVD development. The discussion culminates with the potential use of flavonoids via exerting their biological effects on cellular senescence to reduce CVD incidence. This summary will provide valuable insights for cardiovascular drug design, development and clinical applications leveraging flavonoids.

Epigenetically regulated inflammation in vascular senescence and renal progression of chronic kidney disease

Chronic kidney disease (CKD) and its complications, including vascular senescence and progressive renal fibrosis, are associated with inflammation. Vascular senescence, in particular, has emerged as an instrumental mediator of vascular inflammation that potentially worsens renal function. Epigenetically regulated inflammation involving histone modification, DNA methylation, actions of microRNAs and other non-coding RNAs, and their reciprocal reactions during vascular senescence and inflammaging are underappreciated. Their synergistic effects can contribute to CKD progression. Vascular senotherapeutics or pharmacological anti-senescent therapies based on epigenetic machineries can therefore be plausible options for ameliorating vascular aging and even halting the worsening of renal fibrosis. These include histone deacetylase modulators, histone methyltransferase modulators, other histone modification effectors, DNA methyltransferase inhibitors, telomerase reverse transcriptase enhancers, microRNA mimic delivery, and small molecules with microRNA-regulating potentials. Some of these molecules have already been tested and have shown anecdotal evidence for treating uremic vasculopathy and renal fibrosis, supporting the feasibility of this approach.

Reactive Carbonyl Species and Protein Lipoxidation in Atherogenesis

Atherosclerosis is a multifactorial disease of medium and large arteries, characterized by the presence of lipid-rich plaques lining the intima over time. It is the main cause of cardiovascular diseases and death worldwide. Redox imbalance and lipid peroxidation could play key roles in atherosclerosis by promoting a bundle of responses, including endothelial activation, inflammation, and foam cell formation. The oxidation of polyunsaturated fatty acids generates various lipid oxidation products such as reactive carbonyl species (RCS), including 4-hydroxy alkenals, malondialdehyde, and acrolein. RCS covalently bind to nucleophilic groups of nucleic acids, phospholipids, and proteins, modifying their structure and activity and leading to their progressive dysfunction. Protein lipoxidation is the non-enzymatic post-translational modification of proteins by RCS. Low-density lipoprotein (LDL) oxidation and apolipoprotein B (apoB) modification by RCS play a major role in foam cell formation. Moreover, oxidized LDLs are a source of RCS, which form adducts on a huge number of proteins, depending on oxidative stress intensity, the nature of targets, and the availability of detoxifying systems. Many systems are affected by lipoxidation, including extracellular matrix components, membranes, cytoplasmic and cytoskeletal proteins, transcription factors, and other components. The mechanisms involved in lipoxidation-induced vascular dysfunction are not fully elucidated. In this review, we focus on protein lipoxidation during atherogenesis.

Endothelial Senescence: From Macro- to Micro-Vasculature and Its Implications on Cardiovascular Health

Endothelial cells line at the most inner layer of blood vessels. They act to control hemostasis, arterial tone/reactivity, wound healing, tissue oxygen, and nutrient supply. With age, endothelial cells become senescent, characterized by reduced regeneration capacity, inflammation, and abnormal secretory profile. Endothelial senescence represents one of the earliest features of arterial ageing and contributes to many age-related diseases. Compared to those in arteries and veins, endothelial cells of the microcirculation exhibit a greater extent of heterogeneity. Microcirculatory endothelial senescence leads to a declined capillary density, reduced angiogenic potentials, decreased blood flow, impaired barrier properties, and hypoperfusion in a tissue or organ-dependent manner. The heterogeneous phenotypes of microvascular endothelial cells in a particular vascular bed and across different tissues remain largely unknown. Accordingly, the mechanisms underlying macro- and micro-vascular endothelial senescence vary in different pathophysiological conditions, thus offering specific target(s) for therapeutic development of senolytic drugs.

Dendrobine regulates STAT3 to attenuate mitochondrial dysfunction and senescence in vascular endothelial cells triggered by oxidized low-density lipoprotein

Our previous studies have highlighted the potential therapeutic efficacy of dendrobine, an alkaloid, in atherosclerosis (AS), nevertheless, the underlying mechanism remains unclear. This study employs a combination of network pharmacology and in vitro experiments to explore the regulatory pathways involved. Through network pharmacology, the biological function for intersection targets between dendrobine and AS were identified. Molecular docking was conducted to investigate the interaction between the dominant target and dendrobine. Human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) to mimic AS, and the effects of dendrobine on cell viability, lipid deposition, mitochondrial function, and cellular senescence were evaluated. Subsequently, cells were treated with the mitophagy inhibitor Mdivi-1 and the STAT3 agonist colivelin to assess the role of mitophagy and STAT3 signaling in dendrobine regulation. Intersection targets were associated with biological processes, including reactive oxygen species production. Dendrobine attenuated the effects of ox-LDL treatment on HUVECs, mitigating changes in cell activity, lipid deposition, mitochondrial function, and cellular senescence. Both Mdivi-1 and colivelin treatments resulted in decreased cell viability and increased cellular senescence, with colivelin suppressing mitophagy. Cotreatment with Mdivi-1 and colivelin further aggravated cellular senescence and inhibited FoxO signaling. Together, this study indicated that dendrobine regulated the STAT3/FoxO signaling pathway, alleviating mitochondrial dysfunction and cellular senescence. This study contributes valuable insights to the potential clinical application of dendrobine.

Metabolic regulation of endothelial senescence

Endothelial cell (EC) senescence is increasingly recognized as a significant contributor to the development of vascular dysfunction and age-related disorders and diseases, including cancer and cardiovascular diseases (CVD). The regulation of cellular senescence is known to be influenced by cellular metabolism. While extensive research has been conducted on the metabolic regulation of senescence in other cells such as cancer cells and fibroblasts, our understanding of the metabolic regulation of EC senescence remains limited. The specific metabolic changes that drive EC senescence are yet to be fully elucidated. The objective of this review is to provide an overview of the intricate interplay between cellular metabolism and senescence, with a particular emphasis on recent advancements in understanding the metabolic changes preceding cellular senescence. I will summarize the current knowledge on the metabolic regulation of EC senescence, aiming to offer insights into the underlying mechanisms and future research directions.

DYRK1B inhibition exerts senolytic effects on endothelial cells and rescues endothelial dysfunctions

Aging is the major risk factor for chronic disease development. Cellular senescence is a key mechanism that triggers or contributes to age-related phenotypes and pathologies. The endothelium, a single layer of cells lining the inner surface of a blood vessel, is a critical interface between blood and all tissues. Many studies report a link between endothelial cell senescence, inflammation, and diabetic vascular diseases. Here we identify, using combined advanced AI and machine learning, the Dual Specificity Tyrosine Phosphorylation Regulated Kinase 1B (DYRK1B) protein as a possible senolytic target for senescent endothelial cells. We demonstrate that upon induction of senescence in vitro DYRK1B expression is increased in endothelial cells and localized at adherens junctions where it impairs their proper organization and functions. DYRK1B knock-down or inhibition restores endothelial barrier properties and collective behavior. DYRK1B is therefore a possible target to counteract diabetes-associated vascular diseases linked to endothelial cell senescence.

Factors and Pathways Modulating Endothelial Cell Senescence in Vascular Aging

Aging causes a progressive decline in the structure and function of organs. With advancing age, an accumulation of senescent endothelial cells (ECs) contributes to the risk of developing vascular dysfunction and cardiovascular diseases, including hypertension, diabetes, atherosclerosis, and neurodegeneration. Senescent ECs undergo phenotypic changes that alter the pattern of expressed proteins, as well as their morphologies and functions, and have been linked to vascular impairments, such as aortic stiffness, enhanced inflammation, and dysregulated vascular tone. Numerous molecules and pathways, including sirtuins, Klotho, RAAS, IGFBP, NRF2, and mTOR, have been implicated in promoting EC senescence. This review summarizes the molecular players and signaling pathways driving EC senescence and identifies targets with possible therapeutic value in age-related vascular diseases.

Potential Role of Cellular Senescence in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare and chronic lung vasculature disease characterized by pulmonary vasculature remodeling, including abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) and dysfunctional endothelial cells (ECs). Remodeling of the pulmonary vasculature occurs from maturity to senescence, and it has become apparent that cellular senescence plays a central role in the pathogenesis of various degenerative vascular diseases and pulmonary pathologies. Cellular senescence represents a state of stable proliferative arrest accompanied by the senescence-associated secretory phenotype (SASP), which entails the copious secretion of proinflammatory signals in the tissue microenvironment. Evidences show that in PAH patients, higher levels of cytokines, chemokines, and inflammatory mediators can be detected and correlate with clinical outcome. Moreover, senescent cells accrue with age in epithelial, endothelial, fibroblastic, and immunological compartments within human lungs, and evidence showed that ECs and PASMCs in lungs from patients with chronic obstructive pulmonary disease were characterized by a higher number of senescent cells. However, there is little evidence uncovering the molecular pulmonary vasculature senescence in PAH. Herein, we review the cellular senescence in pulmonary vascular remodeling, and emphasize its importance in PAH. We further introduce some signaling pathways which might be involved in vasculature senescence and PAH, with the intent to discuss the possibility of the PAH therapy via targeting cellular senescence and reduce PAH progression and mortality.

A Senolytic-Eluting Coronary Stent for the Prevention of In-Stent Restenosis

The vast majority of drug-eluting stents (DES) elute either sirolimus or one of its analogues. While limus drugs stymie vascular smooth muscle cell (VSMC) proliferation to prevent in-stent restenosis, their antiproliferative nature is indiscriminate and limits healing of the endothelium in stented vessels, increasing the risk of late-stent thrombosis. Oxidative stress, which is associated with vascular injury from stent implantation, can induce VSMCs to undergo senescence, and senescent VSMCs can produce pro-inflammatory cytokines capable of inducing proliferation of neighboring nonsenescent VSMCs. We explored the potential of senolytic therapy, which involves the selective elimination of senescent cells, in the form of a senolytic-eluting stent (SES) for interventional cardiology. Oxidative stress was modeled in vitro by exposing VSMCs to H₂O₂, and H₂O₂-mediated senescence was evaluated by cytochemical staining of senescence-associated β-galactosidase activity and qRT-PCR. Quiescent VSMCs were then treated with the conditioned medium (CM) of H₂O₂-treated VSMCs. Proliferative effects of CM were analyzed by staining for proliferating cell nuclear antigen. Senolytic effects of the first-generation senolytic ABT263 were observed in vitro, and the effects of ABT263 on endothelial cells were also investigated through an in vitro re-endothelialization assay. SESs were prepared by dip coating. Iliofemoral arteries of hypercholesteremic rabbits were implanted with SES, everolimus-eluting stents (EESs), or bare-metal stents (BMSs), and the area of stenosis was measured 4 weeks post-implantation using optical coherence tomography. We found that a portion of H₂O₂-treated VSMCs underwent senescence, and that CM of H₂O₂-treated senescent VSMCs triggered the proliferation of quiescent VSMCs. ABT263 reverted H₂O₂-mediated senescence and the proliferative capacity of senescent VSMC CM. Unlike everolimus, ABT263 did not affect endothelial cell migration and/or proliferation. SES, but not EES, significantly reduced stenosis area in vivo compared with bare-metal stents (BMSs). This study shows the potential of SES as an alternative to current forms of DES.

Endothelial Senescence and the Chronic Vascular Diseases: Challenges and Therapeutic Opportunities in Atherosclerosis

Atherosclerosis is probably one of the paradigms of disease linked to aging. Underlying the physiopathology of atherosclerosis are cellular senescence, oxidative stress, and inflammation. These factors are increased in the elderly and from chronic disease patients. Elevated levels of oxidative stress affect cellular function and metabolism, inducing senescence. This senescence modifies the cell phenotype into a senescent secretory phenotype. This phenotype activates immune cells, leading to chronic systemic inflammation. Moreover, due to their secretory phenotype, senescence cells present an increased release of highlighted extracellular vesicles that will change nearby/neighborhood cells and paracrine signaling. For this reason, searching for specific senescent cell biomarkers and therapies against the development/killing of senescent cells has become relevant. Recently, senomorphic and senolityc drugs have become relevant in slowing down or eliminating senescence cells. However, even though they have shown promising results in experimental studies, their clinical use is still yet to be determined.

Mesenchymal stem cell-derived small extracellular vesicles mitigate oxidative stress-induced senescence in endothelial cells via regulation of miR-146a/Src

Senescent endothelial cells (ECs) could impair the integrity of the blood vessel endothelium, leading to vascular aging and a series of diseases, such as atherosclerosis, diabetes. Preventing or mitigating EC senescence might serve as a promising therapeutic paradigm for these diseases. Recent studies showed that small extracellular vesicles (sEV) have the potential to transfer bioactive molecules into recipient cells and induce phenotypic changes. Since mesenchymal stem cells (MSCs) have long been postulated as an important source cell in regenerative medicine, herein we investigated the role and mechanism of MSC-derived sEV (MSC-sEV) on EC senescence. In vitro results showed that MSC-sEV reduced senescent biomarkers, decreased senescence-associated secretory phenotype (SASP), rescued angiogenesis, migration and other dysfunctions in senescent EC induced by oxidative stress. In the In vivo natural aging and type-2 diabetes mouse wound-healing models (both of which have senescent ECs), MSC-sEV promoted wound closure and new blood vessel formation. Mechanically, miRNA microarray showed that miR-146a was highly expressed in MSC-sEV and also upregulated in EC after MSC-sEV treatment. miR-146a inhibitors abolished the stimulatory effects of MSC-sEV on senescence. Moreover, we found miR-146a could suppress Src phosphorylation and downstream targets VE-cadherin and Caveolin-1. Collectively, our data indicate that MSC-sEV mitigated endothelial cell senescence and stimulate angiogenesis through miR-146a/Src.

Targeting senescent cells for vascular aging and related diseases

Cardiovascular diseases are a serious threat to human health, especially in the elderly. Vascular aging makes people more susceptible to cardiovascular diseases due to significant dysfunction or senescence of vascular cells and maladaptation of vascular structure and function; moreover, vascular aging is currently viewed as a modifiable cardiovascular risk factor. To emphasize the relationship between senescent cells and vascular aging, we first summarize the roles of senescent vascular cells (endothelial cells, smooth muscle cells and immune cells) in the vascular aging process and inducers that contribute to cellular senescence. Then, we present potential strategies for directly targeting senescent cells (senotherapy) or preventively targeting senescence inducers (senoprevention) to delay vascular aging and the development of age-related vascular diseases. Finally, based on recent research, we note some important questions that still need to be addressed in the future.

Vascular Endothelial Senescence: Pathobiological Insights, Emerging Long Noncoding RNA Targets, Challenges and Therapeutic Opportunities

Cellular senescence is a stable form of cell cycle arrest in response to various stressors. While it serves as an endogenous pro-resolving mechanism, detrimental effects ensue when it is dysregulated. In this review, we introduce recent advances for cellular senescence and inflammaging, the underlying mechanisms for the reduction of nicotinamide adenine dinucleotide in tissues during aging, new knowledge learned from p16 reporter mice, and the development of machine learning algorithms in cellular senescence. We focus on pathobiological insights underlying cellular senescence of the vascular endothelium, a critical interface between blood and all tissues. Common causes and hallmarks of endothelial senescence are highlighted as well as recent advances in endothelial senescence. The regulation of cellular senescence involves multiple mechanistic layers involving chromatin, DNA, RNA, and protein levels. New targets are discussed including the roles of long noncoding RNAs in regulating endothelial cellular senescence. Emerging small molecules are highlighted that have anti-aging or anti-senescence effects in age-related diseases and impact homeostatic control of the vascular endothelium. Lastly, challenges and future directions are discussed including heterogeneity of endothelial cells and endothelial senescence, senescent markers and detection of senescent endothelial cells, evolutionary differences for immune surveillance in mice and humans, and long noncoding RNAs as therapeutic targets in attenuating cellular senescence. Accumulating studies indicate that cellular senescence is reversible. A better understanding of endothelial cellular senescence through lifestyle and pharmacological interventions holds promise to foster a new frontier in the management of cardiovascular disease risk.

Combined LDL and VLDL Electronegativity Correlates with Coronary Heart Disease Risk in Asymptomatic Individuals

The most electronegative constituents of human plasma LDL (i.e., L5) and VLDL (i.e., V5) are highly atherogenic. We determined whether the combined electronegativity of L5 and V5 (i.e., L5 + V5) plays a role in coronary heart disease (CHD). In 33 asymptomatic individuals (ages 32–64), 10-year hard CHD risk correlated with age (r = 0.42, p = 0.01). However, in age-adjusted analyses, 10-year hard CHD risk correlated with L5 + V5 plasma concentration (r = 0.43, p = 0.01) but not age (p = 0.74). L5 + V5 plasma concentration was significantly greater in the group with high CHD risk (39.4 ± 22.0 mg/dL; n = 17) than in the group with low CHD risk (16.9 ± 14.8 mg/dL; n = 16; p = 0.01). In cultured human aortic endothelial cells, L5 + V5 treatment induced significantly more senescence-associated–β-Gal activity than did equal concentrations of L1 + V1 (n = 4, p < 0.001). To evaluate the in vivo relevance of these findings, we fed ApoE^−/− and wild-type mice with a high-fat diet and found that plasma LDL, VLDL, and LDL + VLDL from ApoE^−/− mice exhibited significantly greater electrophoretic mobility than did wild-type counterparts (n = 6, p < 0.01). The increased electronegativity of LDL and VLDL in ApoE^−/− mice was accompanied by increased aortic lipid accumulation and cellular senescence (n = 6, p < 0.05). Clinical trials are warranted to test the predictive value of L5 + V5 concentration in patients with CHD.

Age-Related Impairment of Structure and Function of Iliac Artery Endothelium in Rats Is Improved by Elevated Fluid Shear Stress

Background

Aging plays an important role in endothelial dysfunction. Fluid shear stress (FSS) can activate endothelial cells (ECs). Herein, we tested the hypothesis that this endothelial impairment could be improved by elevated FSS (EFSS) in aged rats.

Material/Methods

EFSS was created through ligation of the unilateral common iliac artery in 20-−month-old rats, evaluated by measuring blood flow velocity with Doppler spectrum. The effect of FSS on aged ECs was examined by senescence-associated β-galactosidase (SA-β-Gal) staining, ultrastructural observation, and immunostaining and qPCR analysis of eNOS and SIRT1 expression on both the mRNA and protein levels.

Results

(1) FSS was significantly increased in the right common iliac artery (RCIA) in rats with the ligation of the left common iliac artery (LCIA). (2) SA-β-Gal staining was significantly attenuated by EFSS in the RCIA of aged rats. (3) Ultrastructural observation showed that ECs in the RCIA of normal aged rats became irregular and enlarged, with increasingly polypoid nuclei and fewer mitochondria, whereas ECs in the RCIA of aged rats with LCIA ligation became more prominent and contained more mitochondria. (4) eNOS and SIRT1 expression in the RCIA of aged rats with LCIA ligation was significantly upregulated compared with that in control group rats.

Conclusions

The present study for the first time shows that EFSS has the ability to improve age-related impairment of endothelial structure and functions.

Nrf2 in aging - Focus on the cardiovascular system

Aging is the most critical risk factor for the development of cardiovascular diseases and their complications. Therefore, the fine-tuning of cellular response to getting older is an essential target for prospective therapies in cardiovascular medicine. One of the most promising targets might be the transcription factor Nrf2, which drives the expression of cytoprotective and antioxidative genes. Importantly, Nrf2 expression correlates with potential lifespan in rodents. However, the effect of Nrf2 activity in vascular diseases might be ambiguous and strongly depend on the cell type. On the one hand, the Nrf2 activity may protect cells from oxidative stress and senescence, on the other hand, total lack of Nrf2 is protective against atherosclerosis development. Therefore, this review aims to discuss the current knowledge on the role played by the transcription factor Nrf2 in cardiovascular diseases and its potential effects on aging.

The Impact of Uremic Toxins on Vascular Smooth Muscle Cell Function

Chronic kidney disease (CKD) is associated with profound vascular remodeling, which accelerates the progression of cardiovascular disease. This remodeling is characterized by intimal hyperplasia, accelerated atherosclerosis, excessive vascular calcification, and vascular stiffness. Vascular smooth muscle cell (VSMC) dysfunction has a key role in the remodeling process. Under uremic conditions, VSMCs can switch from a contractile phenotype to a synthetic phenotype, and undergo abnormal proliferation, migration, senescence, apoptosis, and calcification. A growing body of data from experiments in vitro and animal models suggests that uremic toxins (such as inorganic phosphate, indoxyl sulfate and advanced-glycation end products) may directly impact the VSMCs’ physiological functions. Chronic, low-grade inflammation and oxidative stress—hallmarks of CKD—are also strong inducers of VSMC dysfunction. Here, we review current knowledge about the impact of uremic toxins on VSMC function in CKD, and the consequences for pathological vascular remodeling.

Endothelial replicative senescence delayed by the inhibition of MTORC1 signaling involves MicroRNA-107

Accumulation of senescent endothelial cells can contribute to endothelium dysfunction. Suppression of MTOR signaling has been shown to delay senescence but the mechanism that underpins this effect, particularly one that involves miRNAs, remains to be further defined. This study sought to identify miRNAs involved in MTORC1-mediated inhibition of replicative senescence in endothelial cells. Pre-senescent HUVECs were prolonged treated with low dose rapamycin (1 nM), an MTOR inhibitor. Rapamycin treatment down-regulated the phosphorylated MTOR, RPS6 and 4EBP1 expressions, which confirmed MTORC1 suppression. Prolonged low dose rapamycin treatment has significantly reduced the percentage of senescence-associated beta galactosidase (SA-β gal) positively stained senescent cells and P16INK4A expression in these cells. On the contrary, the percentage of BrdU-labelled proliferating cells has significantly increased. RPTOR, a positive regulator of MTORC1 was knockdown using RPTOR siRNA to inhibit MTORC1 activation. RPTOR knockdown was evidenced by significant suppressions of RPTOR mRNA and protein expression levels. In these cells, the expression of miR-107 was down-regulated whereas miR-145-5p and miR-217 were up-regulated. Target gene prediction revealed PTEN as the target of miR-107 and this was confirmed by biotin pull-down assay. Over-expression of miR-107 has decreased PTEN expression, increased MTORC1 activity, induced cell cycle arrest at G0/G1 phase and up-regulated P16INK4A expression but mitigated tube formation. Collectively, our findings revealed that delayed endothelial replicative senescence caused by the inhibition of MTORC1 activation could be modulated by miR-107 via its influence on PTEN.

MicroRNA-214-3p: A link between autophagy and endothelial cell dysfunction in atherosclerosis

AIM

Endothelial cell injury assumes a fundamental part in the pathogenesis of atherosclerosis, and endothelial cell autophagy has protective effects on the development of atherosclerosis, although the underlying molecular regulation mechanism is indistinct. This study aimed to investigate whether microRNA-214-3p (miR-214-3p) is involved in the endothelial cell autophagy regulation of atherosclerosis.

METHODS

We utilized ApoE^-/- mice provided with a high-fat diet (HFD) as atherosclerosis model. We analysed the level of miR-214-3p and the levels of autophagy-related protein 5 (ATG5) and autophagy-related protein 12 (ATG12) in the purified CD31⁺ endothelial cells from mouse aorta. Bioinformatics analysis and a dual-luciferase reporter assay were performed to confirm the binding target of miR-214-3p. In vitro study, human umbilical vein endothelial cells (HUVECs) were transfected with miR-214-3p mimics/inhibitor and stimulated with 100 μg/mL oxidized low-density lipoprotein (ox-LDL) for 12 hours to initiate a stress-repairing autophagic process.

RESULTS

In mouse models, we identified an inverse correlation between miR-214-3p, ATG5 and ATG12. We observed that in young HUVECs, ox-LDL-initiated autophagy was repressed by miR-214-3p overexpression, as evaluated by autophagic protein analysis, microtubule-associated protein 1 light chain 3B-II (LC3B-II) immunofluorescence assay and transmission electron microscopy (TEM). Also, miR-214-3p promoted ox-LDL accumulation in HUVECs and THP-1 monocyte adhesion. Conversely, in old HUVECs, suppression of miR-214-3p preserved the ability to initiate a protective autophagy reaction to the ox-LDL stimulation.

CONCLUSION

miR-214-3p regulates ox-LDL-initiated autophagy in HUVECs by directly targeting the 3'UTR of ATG5 and may have a suitable role in the pathogenesis of atherosclerosis.

The role of cellular senescence in aging through the prism of Koch-like criteria

Since Hayflick's discovery of cellular senescence (CS), a great volume of knowledge in the field has been accumulated and intensively discussed. Here, we attempted to organize the evidence "for" and "against" the hypothesized causal role of CS in aging. For that purpose, we utilized robust Koch-like logical criteria, based on the assumption that some quantitative relationships between the accumulation of senescent cells and aging rate should exist. If so, it could be expected that (i) the "CS load" would be greater in the premature aging phenotype and lesser in longevity phenotype; (ii) CS would promote age-related diseases, and (iii) the interventions that modulate the levels of senescent cells should also modulate health/lifespan. The analysis shows that CS can be considered a causal factor of aging and an important player in various age-related diseases, though its contribution may greatly vary across species. While the relative impact of senescent cells to aging could overall be rather limited and their elimination is hardly expected to be the "fountain of youth", the potential benefits of the senolytic strategy seems a promising option in combating age-related diseases and extending healthspan.

Suppression of Transforming Growth Factor-β Signaling Delays Cellular Senescence and Preserves the Function of Endothelial Cells Derived from Human Pluripotent Stem Cells

Transplantation of vascular cells derived from human pluripotent stem cells (hPSCs) offers an attractive noninvasive method for repairing the ischemic tissues and for preventing the progression of vascular diseases. Here, we found that in a serum‐free condition, the proliferation rate of hPSC‐derived endothelial cells is quickly decreased, accompanied with an increased cellular senescence, resulting in impaired gene expression of endothelial nitric oxide synthase (eNOS) and impaired vessel forming capability in vitro and in vivo. To overcome the limited expansion of hPSC‐derived endothelial cells, we screened small molecules for specific signaling pathways and found that inhibition of transforming growth factor‐β (TGF‐β) signaling significantly retarded cellular senescence and increased a proliferative index of hPSC‐derived endothelial cells. Inhibition of TGF‐β signaling extended the life span of hPSC‐derived endothelial and improved endothelial functions, including vascular network formation on Matrigel, acetylated low‐density lipoprotein uptake, and eNOS expression. Exogenous transforming growth factor‐β1 increased the gene expression of cyclin‐dependent kinase inhibitors, p15^Ink4b, p16^Ink4a, and p21^CIP1, in endothelial cells. Conversely, inhibition of TGF‐β reduced the gene expression of p15^Ink4b, p16^Ink4a, and p21^CIP1. Our findings demonstrate that the senescence of newly generated endothelial cells from hPSCs is mediated by TGF‐β signaling, and manipulation of TGF‐β signaling offers a potential target to prevent vascular aging. Stem Cells Translational Medicine2017;6:589–600

Phenyl 2-pyridyl ketoxime induces cellular senescence-like alterations via nitric oxide production in human diploid fibroblasts

Phenyl-2-pyridyl ketoxime (PPKO) was found to be one of the small molecules enriched in the extracellular matrix of near-senescent human diploid fibroblasts (HDFs). Treatment of young HDFs with PPKO reduced the viability of young HDFs in a dose- and time-dependent manner and resulted in senescence-associated β-galactosidase (SA-β-gal) staining and G2/M cell cycle arrest. In addition, the levels of some senescence-associated proteins, such as phosphorylated ERK1/2, caveolin-1, p53, p16(ink4a), and p21(waf1), were elevated in PPKO-treated cells. To monitor the effect of PPKO on cell stress responses, reactive oxygen species (ROS) production was examined by flow cytometry. After PPKO treatment, ROS levels transiently increased at 30 min but then returned to baseline at 60 min. The levels of some antioxidant enzymes, such as catalase, peroxiredoxin II and glutathione peroxidase I, were transiently induced by PPKO treatment. SOD II levels increased gradually, whereas the SOD I and III levels were biphasic during the experimental periods after PPKO treatment. Cellular senescence induced by PPKO was suppressed by chemical antioxidants, such as N-acetylcysteine, 2,2,6,6-tetramethylpiperidinyloxy, and L-buthionine-(S,R)-sulfoximine. Furthermore, PPKO increased nitric oxide (NO) production via inducible NO synthase (iNOS) in HDFs. In the presence of NOS inhibitors, such as L-NG-nitroarginine methyl ester and L-NG-monomethylarginine, PPKO-induced transient NO production and SA-β-gal staining were abrogated. Taken together, these results suggest that PPKO induces cellular senescence in association with transient ROS and NO production and the subsequent induction of senescence-associated proteins.

Cellular Senescence and Vascular Disease: Novel Routes to Better Understanding and Therapy

Cellular senescence is a definable fate of cells within aging, diseased, and remodelling tissues. The traditional hallmark of cellular senescence is permanent cell cycle arrest but the senescent state is also accompanied by secretion of proteins that can reinforce the senescent phenotype and adversely affect the local tissue environment. Assessment for cellular markers of senescence has revealed the existence of senescent smooth muscle cells and senescent endothelial cells in vessels of patients with atherosclerosis and hypertension. This raises the possibility that cellular senescence might contribute to the initiation or progression of vascular disease. Potential disease-promoting pathways include blunted replicative reserve, reduced nitric oxide production, and increased cellular stiffness. Moreover, the secretory phenotype of senescent vascular cells might promote vascular degeneration through chronic inflammation and extracellular matrix degradation. Slowing of vascular cell aging and selective clearing of cells that have become senescent are emerging as exciting possibilities for controlling vascular disease.

Senescent Vascular Smooth Muscle Cells Drive Inflammation Through an Interleukin-1α-Dependent Senescence-Associated Secretory Phenotype

OBJECTIVE

Vascular smooth muscle cells (VSMCs) that become senescent are both present within atherosclerotic plaques and thought to be important to the disease process. However, senescent VSMCs are generally considered to only contribute through inaction, with failure to proliferate resulting in VSMC- and collagen-poor unstable fibrous caps. Whether senescent VSMCs can actively contribute to atherogenic processes, such as inflammation, is unknown.

APPROACH AND RESULTS

We find that senescent human VSMCs develop a proinflammatory state known as a senescence-associated secretory phenotype. Senescent human VSMCs release high levels of multiple cytokines and chemokines driven by secreted interleukin-1α acting in an autocrine manner. Consequently, the VSMC senescence-associated secretory phenotype promotes chemotaxis of mononuclear cells in vitro and in vivo. In addition, senescent VSMCs release active matrix metalloproteinase-9, secrete less collagen, upregulate multiple inflammasome components, and prime adjacent endothelial cells and VSMCs to a proadhesive and proinflammatory state. Importantly, maintaining the senescence-associated secretory phenotype places a large metabolic burden on senescent VSMCs, such that they can be selectively killed by inhibiting glucose utilization.

CONCLUSIONS

Senescent VSMCs may actively contribute toward the chronic inflammation associated with atherosclerosis through the interleukin-1α-driven senescence-associated secretory phenotype and the priming of adjacent cells to a proatherosclerotic state. These data also suggest that inhibition of this potentially important source of chronic inflammation in atherosclerosis requires blockade of interleukin-1α and not interleukin-1β.

Noncoding RNA in age-related cardiovascular diseases

Eukaryotic gene expression is tightly regulated transcriptionally and post-transcriptionally by a host of noncoding (nc)RNAs. The best-studied class of short ncRNAs, microRNAs, mainly repress gene expression post-transcriptionally. Long noncoding (lnc)RNAs, which comprise RNAs differing widely in length and function, can regulate gene transcription as well as post-transcriptional mRNA fate. Collectively, ncRNAs affect a broad range of age-related physiologic deteriorations and pathologies, including reduced cardiovascular vigor and age-associated cardiovascular disease. This review presents an update of our understanding of regulatory ncRNAs contributing to cardiovascular health and disease as a function of advancing age. We will discuss (1) regulatory ncRNAs that control aging-associated cardiovascular homeostasis and disease, (2) the concepts, approaches, and methodologies needed to study regulatory ncRNAs in cardiovascular aging and (3) the challenges and opportunities that age-associated regulatory ncRNAs present in cardiovascular physiology and pathology. This article is part of a Special Issue entitled "CV Aging".

Foam cell-derived 4-hydroxynonenal induces endothelial cell senescence in a TXNIP-dependent manner

Vascular endothelial cell (VEC) senescence is considered an early event in the development of atherosclerotic lesions. Stressful stimuli, in particular oxidative stress, have been linked to premature senescence in the vasculature. Foam cells are a major source of reactive oxygen species and may play a role in the induction of VEC senescence; hence, we investigated their involvement in the induction of VEC senescence in a co-culture transwell system. Primary bovine aortic endothelial cells, exposed to the secretome of THP-1 monocyte-derived foam cells, were analysed for the induction of senescence. Senescence associated β-galactosidase activity and the expression of p16 and p21 were increased, whereas phosphorylated retinoblastoma protein was reduced. This senescent phenotype was mediated by 4-hydroxnonenal (4-HNE), a lipid peroxidation product secreted from foam cells; scavenging of 4-HNE in the co-culture medium blunted this effect. Furthermore, both foam cells and 4-HNE increased the expression of the pro-oxidant thioredoxin-interacting protein (TXNIP). Molecular manipulation of TXNIP expression confirmed its involvement in foam cell-induced senescence. Previous studies showed that peroxisome proliferator-activated receptor (PPAR)δ was activated by 4-hydroalkenals, such as 4-HNE. Pharmacological interventions supported the involvement of the 4-HNE-PPARδ axis in the induction of TXNIP and VEC senescence. The association of TXNIP with VEC senescence was further supported by immunofluorescent staining of human carotid plaques in which the expression of both TXNIP and p21 was augmented in endothelial cells. Collectively, these findings suggest that foam cell-released 4-HNE activates PPARδ in VEC, leading to increased TXNIP expression and consequently to senescence.

Senescence-Induced Oxidative Stress Causes Endothelial Dysfunction

Age is a risk factor for cardiovascular disease, suggesting a causal relationship between age-related changes and vascular damage. Endothelial dysfunction is an early pathophysiological hallmark in the development of cardiovascular disease. Senescence, the cellular equivalent of aging, was proposed to be involved in endothelial dysfunction, but functional data showing a causal relationship are missing.Endothelium-dependent vasodilation was measured in aortic rings ex vivo. We investigated aortas from aged C57Bl/6 mice (24-28 months), in which p16 (INK4a) and p19 (ARF) expression, markers of stress-induced senescence, were significantly induced compared to young controls (4-6 months). To reflect telomere shortening in human aging, we investigated aortas from telomerase deficient (Terc(-/-)) mice of generation 3 (G3). Endothelium-dependent vasodilation in aged wildtype and in Terc(-/-) G3 mice was impaired. A combination of the superoxide dismutase mimetic 1-Oxyl-2,2,6, 6-tetramethyl-4-hydroxypiperidine (TEMPOL) and the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor apocynin significantly improved endothelium-dependent vasodilation in aged wildtype and Terc(-/-) G3 mice compared to untreated controls. We show that both, aging and senescence induced by telomere shortening, cause endothelial dysfunction that can be restored by antioxidants, indicating a role for oxidative stress. The observation that cellular senescence is a direct signalling event leading to endothelial dysfunction holds the potential to develop new targets for the prevention of cardiovascular disease.

Emerging issues in radiogenic cataracts and cardiovascular disease

In 2011, the International Commission on Radiological Protection issued a statement on tissue reactions (formerly termed non-stochastic or deterministic effects) to recommend lowering the threshold for cataracts and the occupational equivalent dose limit for the crystalline lens of the eye. Furthermore, this statement was the first to list circulatory disease (cardiovascular and cerebrovascular disease) as a health hazard of radiation exposure and to assign its threshold for the heart and brain. These changes have stimulated various discussions and may have impacts on some radiation workers, such as those in the medical sector. This paper considers emerging issues associated with cataracts and cardiovascular disease. For cataracts, topics dealt with herein include (i) the progressive nature, stochastic nature, target cells and trigger events of lens opacification, (ii) roles of lens protein denaturation, oxidative stress, calcium ions, tumor suppressors and DNA repair factors in cataractogenesis, (iii) dose rate effect, radiation weighting factor, and classification systems for cataracts, and (iv) estimation of the lens dose in clinical settings. Topics for cardiovascular disease include experimental animal models, relevant surrogate markers, latency period, target tissues, and roles of inflammation and cellular senescence. Future research needs are also discussed.

MicroRNAs in vascular aging and atherosclerosis

Lipid dysfunction, inflammation, immune response and advanced aging are major factors involved in the initiation and progression of atherosclerosis. MicroRNAs (miRNAs) have emerged as important regulators of gene expression that post transcriptionally modify cellular responses and function. MiRNA's are crucially involved in several vascular pathologies which show a clear association with increasing age (Dimmeler and Nicotera, 2013). Several studies have demonstrated that miRNA dysregulation has a crucial role in the development of atherosclerotic disease, encompassing every step from plaque formation to destabilization and rupture. This review will present the recent advances in the elucidation of the complex pathophysiological mechanisms in vascular aging by which miRNAs regulate the different phases of atherosclerotic process with a focus on endothelial cells and both, innate and adaptive immune systems. Furthermore, the future areas of research and potential clinical strategies will be discussed.

Hormone-brain-aging relationships, broadly reactive with imidazole-containing dipeptides: targeting of telomere attrition as an aging biomarker and dynamic telomerase activity flirting

It has been documented that telomere-associated cellular senescence may contribute to certain age-related disorders, and telomere length (TL) may be an informative biomarker of healthy aging. Hormone-brain-aging behavior-modulated telomere dynamics and changes in telomerase activity are consistent elements of cellular alterations associated with changes in proliferative state, and these processes are consequently considered as the new therapeutic drug targets for physiological control with advanced drug delivery and nutritional formulations. We raise and support a therapeutic concept of using nonhydrolyzed forms of naturally occurring neuron-specific imidazole dipeptide-based compounds carnosine and carcinine, making it clinically possible that slowing down the rate of telomere shortening could slow down the human aging process in specific tissues where proliferative senescence is known to occur, with the demonstrated evidence of telomere shortening that appeared to be a hallmark of oxidative stress and disease. Carnosine released from skeletal muscle during exercise may be transported into the hypothalamic tuberomammillary nucleus (TMN) histamine neurons and hydrolyzed. The resulting L-histidine may subsequently be converted into histamine, which could be responsible for the effects of carnosine on neurotransmission and hormone-like antiaging physiological function. The preliminary longitudinal studies of elderly individuals suggest that longer telomeres are associated with better survival, and an advanced oral nutritional support with nonhydrolyzed carnosine (or carcinine and patented compositions thereof) is a useful therapeutic tool for a critical TL maintenance that may fundamentally be applied in the treatment of age-related sight-threatening eye disorders, prolonged life expectancy, increased survival and chronological age of an organism in health control, smoking behavior, and disease. "Our pleasures were simple-they included survival." -Dwight D. Eisenhower, 34th President of the United States, 1953-1961.

Endothelial cell senescence and age-related vascular diseases

Advanced age is an independent risk factor for ageing-related complex diseases, such as coronary artery disease, stroke, and hypertension, which are common but life threatening and related to the ageing-associated vascular dysfunction. On the other hand, patients with progeria syndromes suffer from serious atherosclerosis, suggesting that the impaired vascular functions may be critical to organismal ageing, or vice versa. However, it remains largely unknown how vascular cells, particularly endothelial cell, become senescent and how the senescence impairs the vascular functions and contributes to the age-related vascular diseases over time. Here, we review the recent progress on the characteristics of vascular ageing and endothelial cell senescence in vitro and in vivo, evaluate how genetic and environmental factors as well as autophagy and stem cell influence endothelial cell senescence and how the senescence contributes to the age-related vascular phenotypes, such as atherosclerosis and increased vascular stiffness, and explore the possibility whether we can delay the age-related vascular diseases through the control of vascular ageing.

Time-effect relationship of extracts from ginseng, notoginseng and chuanxiong on vascular endothelial cells senescence

OBJECTIVE

To observe the time-effect relation of extracts from ginseng, notoginseng and chuanxiong on angiotensin II (Ang II)-induced senescence of vascular endothelial cells and explore the feature of Chinese medicine against vascular diseases.

METHODS

Human umbilical vein endothelial cells (HUVECs) cultured in vitro were stimulated with 10(-6) mol/L AngII to induce cell senescence, which were divided into 4 groups, the blank control group, the Ang II model group, the extracts group and the telmisartan group. The β-gal was used to identify senescence of cells, the cell counting kit-8 method was applied to assess the cell viability, the cell function was examined with the level of endothelial nitric oxide synthase (eNOS) and the flow cytometry was used for analyzing the cell cycle changes.

RESULTS

Compared with the control cells, the cells positive for β-gal staining was significantly increased in the Ang II model group, and showed cell cycle arrest at G0/G1 phase with decreased S and G2/M phase cell percentage, eNOS expression and cell viability (P<0.05). The extracts and telmisartan treatment of Ang II-induced cells resulted in decreased β-gal positive cells with a reduction in G0/G1 phase cells and an increasing in S, G2/M phase cells and eNOS expression (P<0.05). At 24 h, the extracts were more effective than telmisartan (P<0.05); while telmisartan was more effective at 48 h (P<0.05).

CONCLUSION

Extracts from ginseng, notoginseng and chuanxiong can delay Ang II-induced aging of HUVECs and may play an important role in early senescence.

Telomere, aging and age-related diseases

Aging is an inevitable biological process that affects most living organisms. The process of aging is regulated at the level of the organism, as well as at the level of tissues and cells. Despite the enormous consequences associated with the aging process, relatively little systematic effort has been expended on the scientific understanding of this important life process. Many theories have been proposed to explain the aging process, the centerpiece of which is molecular damage. Located at the ends of eukaryotic chromosomes and synthesized by telomerase, telomeres maintain the stabilization of chromosomes. Thus, the loss of telomeres may lead to DNA damage. The relationship between cellular senescence and telomere shortening is well established. Furthermore, telomere attrition occurs with age, and is proposed to be a fundamental factor in the aging process. Here, we review the contemporary literatures to explore the current views on the correlation of telomere loss and telomerase action with aging and age-related diseases.

Icariin delays homocysteine-induced endothelial cellular senescence involving activation of the PI3K/AKT-eNOS signaling pathway

CONTEXT

Homocysteine-induced endothelial cellular senescence may contribute to some cardiovascular disorders. Icariin (ICA), a flavonoid derived from Epimedium sagittatum Maxim. (Berberidaceae), has been reported to increase production of nitric oxide (NO) and reduce reactive oxygen species (ROS) levels in human umbilical vein endothelial cells (HUVECs).

OBJECTIVE

To observe the effects of ICA on homocysteine-induced senescence and the underlying mechanisms in HUVECs.

MATERIALS AND METHODS

ICA at concentrations of 0.1, 1, and 5 μM was added into homocysteine pretreated HUVECs. Cellular senescence was assayed by senescence-associated β-galactosidase (SA-β-gal) staining and cumulative population doublings (CPDs). ICA (5 μM) was given orally to homocysteine-treated rats, luminal surface of aortic artery of rats was subjected to SA-β-gal staining. Protein expression was measured by western blot.

RESULTS

Homocysteine significantly increased cellular senescence both in vitro and in vivo. After treatment by ICA, the percentage of SA-β-gal-positive cells, and the ROS level significantly decreased. The CPDs were partially restored. ICA also significantly reduced the mean density of SA-β-gal staining in vivo. We found that NO production and phosphorylation of AKT, ERK, and endothelial NO synthase (eNOS) were elevated by ICA in HUVECs. Furthermore, the increased level of NO production was fully abolished by the phosphatidylinositol-3-kinase (PI3K) inhibitor wortmannin. The mitogen-activated protein kinase (MEK) inhibitor PD98059, which can inhibit phosphorylation of ERK, did not show this ability.

DISCUSSION AND CONCLUSION

Our results indicate that ICA delays homocyteine-induced endothelial senescence in vitro and in vivo. Activation of PI3K/Akt-eNOS-dependent signaling pathway may be responsible for this efficacy of ICA.

A relationship exists between replicative senescence and cardiovascular health

A growing body of evidence demonstrates that the accumulation of senescent cells is a plausible ageing mechanism. It has been proposed that the senescence of vascular cells plays a causal role in the development of cardiovascular pathologies. A key prediction arising from this hypothesis is that cultures of cells derived from donors with cardiovascular disease will show reduced in vitro replicative capacities compared to those derived from disease-free controls. Accordingly, we carried out a formal review of the relationship among donor age, cardiovascular health status and maximum population doubling level attained in vitro by cultures of vascular smooth muscle and endothelial cells. Data were available to us on a total of 202 independent cell cultures. An inverse relationship was found to exist between replicative capacity and donor age in both endothelial and vascular smooth muscle cells. Cultures derived from donors with cardiovascular disease showed a lower overall replicative potential than age-matched healthy controls. In general the replicative potential at the start of the lifespan was found to be higher in those individuals without disease than those with disease and the difference in average cumulative population doublings (CPDs) in age-matched individuals in the two groups remained roughly constant throughout the lifetime. These results are consistent with the model in which the inherited replicative capacity of vascular cells is a stronger determinant of the onset of cardiovascular disease later in life, than wear-and-tear throughout the life course.

Antiaging effects of simvastatin on vascular endothelial cells

The anti-inflammatory, antioxidative, and antiarteriosclerosis activities of simvastatin along with its protective effects on the endothelium suggest that it may also have antiaging effects. The aim of this study was to investigate the antiaging effects of simvastatin as well as its effects on sirtuin 1 (SIRT1) expression in endothelial cells. Aged rats and human umbilical vein endothelial cells were treated with simvastatin in the presence and absence of oxidized low-density lipoprotein (OX-LDL). Aortic β-galactosidase staining was undertaken to determine senescence, and SIRT1 protein expression was evaluated using Western blot analysis. After simvastatin therapy, arterial endothelial cell aging was significantly reduced, and SIRT1 expression was significantly increased. The OX-LDL significantly accelerated the senescence of umbilical vein endothelial cells and decreased SIRT1 expression. The OX-LDL-induced downregulation of SIRT1 was blocked by simvastatin. Simvastatin treatment also reduced umbilical vein endothelial cell aging and increased SIRT1 expression.

Endothelial cell senescence is associated with disrupted cell-cell junctions and increased monolayer permeability

Background

Cellular senescence is associated with cellular dysfunction and has been shown to occur in vivo in age-related cardiovascular diseases such as atherosclerosis. Atherogenesis is accompanied by intimal accumulation of LDL and increased extravasation of monocytes towards accumulated and oxidized LDL, suggesting an affected barrier function of vascular endothelial cells. Our objective was to study the effect of cellular senescence on the barrier function of non-senescent endothelial cells.

Methods

Human umbilical vein endothelial cells were cultured until senescence. Senescent cells were compared with non-senescent cells and with co-cultures of non-senescent and senescent cells. Adherens junctions and tight junctions were studied. To assess the barrier function of various monolayers, assays to measure permeability for Lucifer Yellow (LY) and horseradish peroxidase (PO) were performed.

Results

The barrier function of monolayers comprising of senescent cells was compromised and coincided with a change in the distribution of junction proteins and a down-regulation of occludin and claudin-5 expression. Furthermore, a decreased expression of occludin and claudin-5 was observed in co-cultures of non-senescent and senescent cells, not only between senescent cells but also along the entire periphery of non-senescent cells lining a senescent cell.

Conclusions

Our findings show that the presence of senescent endothelial cells in a non-senescent monolayer disrupts tight junction morphology of surrounding young cells and increases the permeability of the monolayer for LY and PO.

Resveratrol reduces vascular cell senescence through attenuation of oxidative stress by SIRT1/NADPH oxidase-dependent mechanisms

OBJECTIVE

Senescence of vascular cells contributes to the development of cardiovascular diseases and the overall aging. This study was undertaken to investigate the effects of resveratrol (Res) on amelioration of vascular cell aging and the role of SIRT1/nicotinamide adenine dinucleotide phosphate (NADPH) oxidase pathway.

METHODS AND RESULTS

Adult male Wistar rats were treated with a high-fat/sucrose diet (HFS) in the presence or absence of Res for 3 months. HFS and in vitro treatment with high glucose increased the senescence cells and reactive oxygen species production in rat aorta and cultured bovine aortic endothelial cells (BAECs), respectively, which was attenuated by Res treatment. Res protected against HFS- or high-glucose-induced increase in NADPH oxidase p47phox expression and decrease in SIRT1 level. Apocynin, a NADPH oxidase inhibitor, down-regulated p47phox protein expression, but had no influence on SIRT1 protein; sirtinol, a SIRT1 inhibitor, aggravated the decrease in SIRT1 protein level and the increase in p47phox protein expression induced by high glucose.

CONCLUSION

Our studies suggested that Res was able to reverse the senescence process in aorta induced by HFS in rats or induced by the exposure to high glucose in cultured BAECs. The underlying mechanism is at least SIRT1/NADPH oxidase pathway dependent.

Is cellular senescence important in pediatric kidney disease?

Somatic cellular senescence (SCS) describes the limited ability of cells to divide. Normally, SCS is associated with physiological aging, but evidence suggests that it may play a role in disease progression, even in young patients. Stressors such as acute injury or chronic inflammation may induce SCS, which in turn exhausts organ regenerative potential. This review summarizes what is known about SCS in the kidney with aging and disease. As most patients with chronic kidney disease (CKD) also develop cardiovascular complications, a second focus of this review deals with the role of SCS in cardiovascular disease. Also, as SCS seems to accelerate CKD and cardiovascular disease progression, developing strategies for new treatment options that overcome SCS or protect a patient from it represents an exciting challenge.

MicroRNA changes in human arterial endothelial cells with senescence: relation to apoptosis, eNOS and inflammation

A senescent phenotype in endothelial cells is associated with increased apoptosis, reduced endothelial nitric oxide synthase (eNOS) and inflammation, which are implicated in arterial dysfunction and disease in humans. We tested the hypothesis that changes in microRNAs are associated with a senescent phenotype in human aortic endothelial cells (HAEC). Compared with early-passage HAEC, late-passage HAEC had a reduced proliferation rate and increased staining for senescence-associated beta-galactosidase and the tumor suppressor p16(INK4a). Late-passage senescent HAEC had reduced expression of proliferation-stimulating/apoptosis-suppressing miR-21, miR-214 and miR-92 and increased expression of tumor suppressors and apoptotic markers. eNOS-suppressing miR-221 and miR-222 were increased and eNOS protein and eNOS activation (phosphorylation at serine1177) were lower in senescent HAEC. Caveolin-1 inhibiting miR-133a was reduced and caveolin-1, a negative regulator of eNOS activity, was elevated in senescent HAEC. Inflammation-repressing miR-126 was reduced and inflammation-stimulating miR-125b was increased, whereas inflammatory proteins were greater in senescent HAEC. Development of a senescent arterial endothelial cell phenotype featuring reduced cell proliferation, enhanced apoptosis and inflammation and reduced eNOS is associated with changes in miRNAs linked to the regulation of these processes. Our results support the hypothesis that miRNAs could play a critical role in arterial endothelial cell senescence.

Sulodexide reduces senescence-related changes in human endothelial cells

Background

Senescent endothelial cells acquire functional properties that make the vascular wall more prone to atherosclerotic changes. We tested whether senescence of the endothelial cells maintained in in vitro culture can be moderated by their simultaneous exposure to sulodexide.

Material/Methods

Replicative aging of the endothelial cells was studied during their 15 passages performed every 4 days in cells cultured in standard medium or in medium supplemented with sulodexide 0.5 LRU/mL. Changes in population doubling time and β-galactosidase activity were used as indexes of aging and compared with other cellular parameters.

Results

Repeated passages of endothelial cells induce their senescence, as reflected by prolongation of the population doubling time, increased β-galactosidase activity, oxidative stress and release of cytokines. Healing of the injured endothelial monolayer is impaired in senescent cells. Sulodexide partially prevents oxidative stress and totally eliminates other senescence-related changes such as increased release of MCP-1, lengthening of the population doubling time, and impaired healing of the cellular monolayer after its mechanical injury.

Conclusions

Sulodexide prevented cellular senescence in cultured endothelial cells, moderating features of the cellular senescence in endothelial cells in in vitro conditions, which potentially may have practical application. The administration of sulodexide could potentially be used in prevention of atherosclerotic changes.

Transcriptional up-regulation of antioxidant genes by PPARδ inhibits angiotensin II-induced premature senescence in vascular smooth muscle cells

This study evaluated peroxisome proliferator-activated receptor (PPAR) δ as a potential target for therapeutic intervention in Ang II-induced senescence in human vascular smooth muscle cells (hVSMCs). Activation of PPARδ by GW501516, a specific agonist of PPARδ, significantly inhibited the Ang II-induced premature senescence of hVSMCs. Agonist-activated PPARδ suppressed the generation of Ang II-triggered reactive oxygen species (ROS) with a concomitant reduction in DNA damage. Notably, GW501516 up-regulated the expression of antioxidant genes, such as glutathione peroxidase 1, thioredoxin 1, manganese superoxide dismutase and heme oxygenase 1. siRNA-mediated down-regulation of these antioxidant genes almost completely abolished the effects of GW501516 on ROS production and premature senescence in hVSMCs treated with Ang II. Taken together, the enhanced transcription of antioxidant genes is responsible for the PPARδ-mediated inhibition of premature senescence through sequestration of ROS in hVSMCs treated with Ang II.