Vascular Senescence Research Articles

CD44 connects autophagy decline and ageing in the vascular endothelium

The decline of endothelial autophagy is closely related to vascular senescence and disease, although the molecular mechanisms connecting these outcomes in vascular endothelial cells (VECs) remain unclear. Here, we identify a crucial role for CD44, a multifunctional adhesion molecule, in controlling autophagy and ageing in VECs. The CD44 intercellular domain (CD44ICD) negatively regulates autophagy by reducing PIK3R4 and PIK3C3 levels and disrupting STAT3-dependent PtdIns3K complexes. CD44 and its homologue clec-31 are increased in ageing vascular endothelium and Caenorhabditis elegans, respectively, suggesting that an age-dependent increase in CD44 induces autophagy decline and ageing phenotypes. Accordingly, CD44 knockdown ameliorates age-associated phenotypes in VECs. The endothelium-specific CD44ICD knock-in mouse is shorter-lived, with VECs exhibiting obvious premature ageing characteristics associated with decreased basal autophagy. Autophagy activation suppresses the premature ageing of human and mouse VECs overexpressing CD44ICD, function conserved in the CD44 homologue clec-31 in C. elegans. Our work describes a mechanism coordinated by CD44 function bridging autophagy decline and ageing.

Influence of Chromosome 9p21.3 rs1333049 Variant on Telomere Length and Their Interactive Impact on the Prognosis of Coronary Artery Disease.

Both telomere shortening and the chromosome 9p21.3 (Chr9p21) rs1333049 (G/C) variant are involved in coronary artery disease (CAD) risk, likely affecting mechanisms related to cell cycle arrest and vascular senescence. The aim of the study was to examine the link between Chr9p21 rs1333049 variant and leucocyte telomere length (LTL), as well as their interactive effect on the risk of major adverse cardiovascular events (MACEs). A cohort of 472 patients with angiographically proven and clinically stable CAD were included in the study. At baseline, the LTL, biochemical parameters, and genotype analysis of Chr9p21 rs1333049 variant were measured in all patients. The primary endpoint of this study was the occurrence of MACE defined as a composite of coronary-related death, nonfatal MI, and coronary revascularization. On multivariable linear regression analysis, age (p = 0.02) and Chr9p21 rs1333049 variant (p = 0.002) were the only independent predictors of LTL levels. Carriers of the CC genotype of this SNP had shorter telomeres than GC carriers (p = 0.02) and GG carriers (p = 0.0005). After a follow-up with a mean period of 62 ± 19 months, 90 patients (19.1%) had MACE. Short LTL was an independent prognostic factor of MACE incidence (HR:2.2; 95% CI: 1.3-3.7; p = 0.005) after adjustment for potential confounders. There was a significant interaction (p = 0.01) between the LTL and rs1333049 variant, with patients with risk-allele C and short LTL having a higher risk (HR:5.8; 95% CI: 1.8-19.2; p = 0.004). A strong relationship between LTL and Chr9p21 rs1333049 variant was identified, and they interactively affect the risk of poor prognosis in CAD patients.

Discovery of deoxyandrographolide and its novel effect on vascular senescence by targeting HDAC1.

Aconitum carmichaelii (Fuzi) is a traditional Chinese medicine that has been widely used in the clinic to save the dying life for over several thousand years. However, the medicinal components of Fuzi in treating vascular senescence (VS) and its potential mechanism remain unclear. In this study, a network pharmacology method was used to explore the possible components and further validated by experiments to get a candidate compound, deoxyandrographolide (DA). DA restrains aging biomarkers, such as p16, p21, γH2A.X, and p53 in vitro and in vivo blood co-culture studies. Histone deacetylase 1 (HDAC1), mouse double minute2 (MDM2), cyclin-dependent kinase 4, and mechanistic target of rapamycin kinase (mTOR) are predicted to be the possible targets of DA based on virtual screening. Subsequent bio-layer interferometry results indicated that DA showed good affinity capability with HDAC1. DA enhances the protein expression of HDAC1 in the angiotensin II-induced senescence process by inhibiting its ubiquitination degradation. Loss of HDAC1 by CRISPR/Cas9 leads to the disappearance of DA's anti-aging property. The enhancement of HDAC1 represses H3K4me3 (a biomarker of chromosomal activity) and improves chromosome stability. RNA sequencing results also confirmed our hypothesis. Our evidence illuminated that DA may achieve as a novel compound in the treatment of VS by improving chromosome stability.

Counteracting Age-Related Netrin-1 Signaling Insufficiency Ameliorates Endothelial Cell Senescence and Angiogenesis Impairment.

Senescent cells that accumulate are regarded as promising therapeutic targets. However, senolytic therapy failed to achieve satisfactory results. We previously discovered that young human plasma improved vascular endothelial cell senescence, and UNC5B might be a novel intervention target. Netrin-1, as a natural ligand of UNC5B, plays roles in multiple age-related vascular disorders, but its involvement in aging is still unclear. Here, we observed a significant decrease in plasma Netrin-1 levels in old healthy subjects compared to the young. In vivo, adeno-associated-virus-mediated delivery of Netrin-1 into aged mice significantly improved functional recovery in a model of hindlimb ischemia, promoted angiogenesis in ischemic tissues, and activated the endothelial nitric oxide synthase. Furthermore, we revealed that low-dose Netrin-1 recombinant protein significantly reduced senescence-associated-β-galactosidase-positive cells, inhibited the P53 pathway, promoted cell migration, increased tubule formation, and elevated nitric oxide production in senescent endothelial cells. However, UNC5B inhibition blocked the pro-angiogenesis effect of low-dose Netrin-1 on senescent cells or aortic rings. In summary, this study depicts that modulating Netrin-1 signaling can result in improved vascular health and Netrin-1 may have therapeutic potential for age-related ischemic diseases.

A Novel Role of Hyaluronic Acid and Proteoglycan Link Protein 1 (HAPLN1) in Delaying Vascular Endothelial Cell Senescence.

Cardiovascular diseases (CVDs) are the most common cardiovascular system disorders. Cellular senescence is a key mechanism associated with dysfunction of aged vascular endothelium. Hyaluronic acid and proteoglycan link protein 1 (HAPLN1) has been known to non-covalently link hyaluronic acid (HA) and proteoglycans (PGs), and forms and stabilizes HAPLN1-containing aggregates as a major component of extracellular matrix. Our previous study showed that serum levels of HAPLN1 decrease with aging. Here, we found that the HAPLN1 gene expression was reduced in senescent human umbilical vein endothelial cells (HUVECs). Moreover, a recombinant human HAPLN1 (rhHAPLN1) decreased the activity of senescence-associated β-gal and inhibited the production of senescence-associated secretory phenotypes, including IL-1β, CCL2, and IL-6. rhHAPLN1 also down-regulated IL-17A levels, which is known to play a key role in vascular endothelial senescence. In addition, rhHAPLN1 protected senescent HUVECs from oxidative stress by reducing cellular reactive oxygen species levels, thus promoting the function and survival of HUVECs and leading to cellular proliferation, migration, and angiogenesis. We also found that rhHAPLN1 not only increases the sirtuin 1 (SIRT1) levels, but also reduces the cellular senescence markers levels, such as p53, p21, and p16. Taken together, our data indicate that rhHAPLN1 delays or inhibits the endothelial senescence induced by various aging factors, such as replicative, IL-17A, and oxidative stress-induced senescence, thus suggesting that rhHAPLN1 may be a promising therapeutic for CVD and atherosclerosis.

Single-Cell Mapping of Large and Small Arteries During Hypertensive Aging.

Vascular aging is directly related to several major diseases including clinical primary hypertension. Conversely, elevated blood pressure itself accelerates vascular senescence. However, the interaction between vascular aging and hypertension has not been characterized during hypertensive aging. To depict the interconnectedness of complex mechanisms between hypertension and aging, we performed single-cell RNA sequencing of aorta, femoral and mesentery arteries, respectively, from male Wistar Kyoto rats and male spontaneously hypertensive rats aging 16 or 72 weeks. We integrated 12 data sets to map the blood vessels of senile hypertension from 3 perspective: vascular aging, hypertension, and vascular type. We found that aging and hypertension independently exerted a significant impact on the alteration of cellular composition and artery remodeling, even greater when superimposed. Consistently, smooth muscle cells (SMCs) underwent phenotypic switching from contractile toward synthetic, apoptotic, and senescent SMCs with aging/hypertension. Furthermore, we identified 3 subclusters of Spp1high, encoding protein osteopontin (OPN), synthetic SMCs, Spp1high matrix activated fibroblasts, and Spp1high scar-associated macrophage involved in hypertensive aging. Spp1high scar-associated macrophage enriched for reactive oxygen species metabolic process and cell migration-associated function. Cell-cell communication analysis revealed Spp1-Cd44 receptor pairing was markedly aggravated in the hypertensive aging condition. Importantly, the concentration of serum OPN significantly potentiated in aged hypertensive patients compared with the normal group. Thus, we provide a comprehensive cell atlas to systematically resolve the cellular diversity and dynamic cellular communication changes of the vessel wall during hypertensive aging, identifying a protein marker OPN as a potential regulator of vascular remodeling during hypertensive aging.

The role of the micro RNA miR-92b-3p in vascular senescence

The role of the micro RNA miR-92b-3p in vascular senescence

The role of miR-127-3p, miR-367-3p, and miR-148a-3p for vascular smooth muscle cell senescence in the context of vascular remodeling

The role of miR-127-3p, miR-367-3p, and miR-148a-3p for vascular smooth muscle cell senescence in the context of vascular remodeling

Single-cell RNA sequencing identifies MFSD2B in megakaryocyte progenitors as a regulator of vascular senescence

Single-cell RNA sequencing identifies MFSD2B in megakaryocyte progenitors as a regulator of vascular senescence

Epigenetic modulation of Drp1-mediated mitochondrial fission by inhibition of S-adenosylhomocysteine hydrolase promotes vascular senescence and atherosclerosis

AimsVascular senescence, which is closely related to epigenetic regulation, is an early pathological condition in cardiovascular diseases including atherosclerosis. Inhibition of S-adenosylhomocysteine hydrolase (SAHH) and the consequent increase of S-adenosylhomocysteine (SAH), a potent inhibitor of DNA methyltransferase, has been associated with an elevated risk of cardiovascular diseases. This study aimed to investigate whether the inhibition of SAHH accelerates vascular senescence and the development of atherosclerosis. Methods and resultsThe case-control study related to vascular aging showed that increased levels of plasma SAH were positively associated with the risk of vascular aging, with an odds ratio (OR) of 3.90 (95% CI, 1.17–13.02). Elevated pulse wave velocity, impaired endothelium-dependent relaxation response, and increased senescence-associated β-galactosidase staining were observed in the artery of SAHH+/- mice at 32 weeks of age. Additionally, elevated expression of p16, p21, and p53, fission morphology of mitochondria, and over-upregulated expression of Drp1 were observed in vascular endothelial cells with SAHH inhibition in vitro and in vivo. Further downregulation of Drp1 using siRNA or its specific inhibitor, mdivi-1, restored the abnormal mitochondrial morphology and rescued the phenotypes of vascular senescence. Furthermore, inhibition of SAHH in APOE−/− mice promoted vascular senescence and atherosclerosis progression, which was attenuated by mdivi-1 treatment. Mechanistically, hypomethylation over the promoter region of DRP1 and downregulation of DNMT1 were demonstrated with SAHH inhibition in HUVECs. ConclusionsSAHH inhibition epigenetically upregulates Drp1 expression through repressing DNA methylation in endothelial cells, leading to vascular senescence and atherosclerosis. These results identify SAHH or SAH as a potential therapeutic target for vascular senescence and cardiovascular diseases.

Danggui-Buxue decoction alleviated vascular senescence in mice exposed to chronic intermittent hypoxia through activating the Nrf2/HO-1 pathway

Context As a major risk factor for cardiovascular diseases (CVD), Obstructive sleep apnea (OSA) is characterized by chronic intermittent hypoxia (CIH). Recent studies indicated that the increased cardiovascular risk in patients with OSA may be mediated by accelerated vascular senescence. Danggui-Buxue decoction (DBD) has been used for treating cardiovascular diseases, but its mechanism of vascular senescence regulation is still unclear. Objective To investigate the effect of DBD on vascular senescence in mice exposed to CIH and to explore the role of the Nrf2/HO-1 pathway. Materials and methods C57BL/6N mice were randomly divided into Normoxia control group (CON), CIH (21%-5% O2, 20 times/h, 8 h/d) exposed group (CIH), and DBD treatment group (intragastrically treated with 2.34, 4.68, or 9.36 g/kg/day of DBD separately for 12 weeks as DBL, DBM, or DBH). Blood pressure, cardiac and vascular function, vascular senescence, inflammation response, oxidative stress, and Nrf2/HO-1 expression were determined. Results DBD (4.68 and 9.36 g/kg) significantly decreased Tail-cuff blood pressure, increased left ventricular systolic function, and alleviated arterial stiffness and vasorelaxation dysfunction in mice exposed to CIH. DBD treatment reduced SA-β-gal activity, decreased p16 (0.68-fold, 0.62-fold), P21 (0.58-fold, 0.52-fold), and p53 expressions (0.67-fold, 0.65-fold), and increased SIRT1 expression (2.22-fold, 2.98-fold) in the aortic. DBD treatment decreased IL-6, NF-κB, and TNF-α expressions, decreased MDA but increased SOD levels, and increased Nrf2 (1.8-fold, 1.89-fold) and HO-1 (2.25-fold, 2.43-fold) expression. Discussion and conclusions DBD could attenuate vascular senescence accelerated by CIH exposure through inhibiting inflammatory response and oxidative stress by activating the Nrf2/HO-1 pathway.

SIRT6 is an epigenetic repressor of thoracic aortic aneurysms via inhibiting inflammation and senescence

Thoracic aortic aneurysms (TAAs) develop asymptomatically and are characterized by dilatation of the aorta. This is considered a life-threating vascular disease due to the risk of aortic rupture and without effective treatments. The current understanding of the pathogenesis of TAA is still limited, especially for sporadic TAAs without known genetic mutation. Sirtuin 6 (SIRT6) expression was significantly decreased in the tunica media of sporadic human TAA tissues. Genetic knockout of Sirt6 in mouse vascular smooth muscle cells accelerated TAA formation and rupture, reduced survival, and increased vascular inflammation and senescence after angiotensin II infusion. Transcriptome analysis identified interleukin (IL)-1β as a pivotal target of SIRT6, and increased IL-1β levels correlated with vascular inflammation and senescence in human and mouse TAA samples. Chromatin immunoprecipitation revealed that SIRT6 bound to the Il1b promoter to repress expression partly by reducing the H3K9 and H3K56 acetylation. Genetic knockout of Il1b or pharmacological inhibition of IL-1β signaling with the receptor antagonist anakinra rescued Sirt6 deficiency mediated aggravation of vascular inflammation, senescence, TAA formation and survival in mice. The findings reveal that SIRT6 protects against TAA by epigenetically inhibiting vascular inflammation and senescence, providing insight into potential epigenetic strategies for TAA treatment.

Naringenin ameliorates vascular senescence and atherosclerosis involving SIRT1 activation.

This study was to explore the potential effects and mechanism of naringenin against vascular senescence in atherosclerosis focusing on the SIRT1-mediated signalling pathway. Aged apoE-/- mice were administrated with naringenin continuously for three months. Lipid parameters in serum and pathological changes and associated protein expression in aorta were examined. In vitro, endothelial cells were treated with H2O2 to induce senescence. Dyslipidemia, atherosclerotic lesion formation and vascular senescence were found in ApoE-/- mice, which were significantly ameliorated by naringenin treatment. Naringenin decreased reactive oxygen species overproduction and enhanced the activities of antioxidant enzymes in aorta. It also decreased mitoROS production and increased protein expressions of mitochondrial biogenesis-related genes in aorta. Moreover, naringenin treatment enhanced aortic protein expression and activity of SIRT1. Meanwhile, naringenin increased deacetylation and protein expression of SIRT1's target genes FOXO3a and PGC1α. In vitro study, the benefits of naringenin on endothelial senescence, oxidative stress and mitochondrial injury as well as protein expressions and acetylated levels of FOXO3a and PGC1α were diminished in cells transfected with SIRT1 siRNA. Naringenin could ameliorate vascular senescence and atherosclerosis and the activation of SIRT1, with subsequent deacetylation and regulation of FOXO3a and PGC1α, is involved in this process.

28-LB: Role of Glycine N-methyltransferase in Electronegative Lipoproteins-Induced Vascular Dysfunction in a Diabetic Rodent Model

Several studies showed low-density lipoprotein (LDL) is associated with high risk of atherosclerosis in patients with diabetes. However, aggressively decreasing total LDL does not prevent all vascular complications. A novel culprit electronegative LDL (L5) was significantly increased in diabetic patients and could induce vascular damage according to our previous studies. However, the mechanism of L5 formation and how to reduce plasma L5 level are still unclear. In the present study, we found both aqueous and ethylacetate extracts of a traditional Chinese remedy Artemisia capillaris (AC) could decrease plasma L5 level in western diet-fed hamster (22.45 and 28.64 vs. 56.83%, respectively), while clinical remedies Simvastatin and Niacin could not. AC could also reverse western diet-induced vascular senescence (b-gal staining) and relaxation dysfunction in aortic rings (63.66±2.14 vs 40.13±1.48% of maximum contraction when compared to western diet hamsters; P<0.01). To further determine the underlying mechanism, we have found that AC reversed western diet-reduced Glycine N-methyltransferase (GNMT) protein abundance and altered several microRNA expression by analyzing the microarray heatmap in liver tissue. In conclusion, AC could significantly reverse western diet-induced vascular injury by lowering plasma L5 level through restore the liver enzyme GNMT activity. Disclosure A. Lee: None. Y. Chen: None. W. Chen: None.

Aerobic Exercise-Mimetic Effects of Resveratrol on the Prevention of Vascular Endothelial Senescence

PURPOSE: Regular exercise has been shown to have anti-aging effects on the vascular system by improving endothelial function and diminishing oxidative stress. However, adherence to an exercise regimen can be difficult for some individuals, particularly those with limited mobility. This study investigated the effects of resveratrol as an exercise mimetic for preventing and improving oxidative stressinduced senescence in vascular endothelial cells.METHODS: Cultured human umbilical vein endothelial cells were used to investigate the reversal effects of laminar shear stress and the protective effects of resveratrol on oxidative stress-induced premature senescence. Senescence was estimated using SA-β-gal staining and western blot analysis, whereas oxidative stress levels were evaluated using MitoSOX staining. Matrigel tube formation and scratch assays were also performed to assess endothelial angiogenic and migration functions.RESULTS: The study showed that laminar shear stress could partly normalize premature endothelial senescence. Resveratrol pretreatment attenuated reactive oxygen species production and prevented senescence in H2O2-induced premature aging. Additionally, resveratrol contributed to maintaining endothelial cells’ angiogenic and migratory functions.CONCLUSIONS: This study demonstrated that laminar shear stress can mitigate the effects of oxidative stress-induced premature senescence. Resveratrol may be a potential substitute for exercise to prevent age-related damage to the endothelium by increasing resistance to oxidative stress and improving endothelial function.

Deficiency of S100 calcium binding protein A9 attenuates vascular dysfunction in aged mice

BackgroundS100 calcium-binding protein A9 (S100A9) is a danger-associated molecular pattern molecule that mediates the inflammatory response. Inflammation is essential in aging-related cardiovascular diseases. However, less is known regarding the role of S100A9 in vascular aging. MethodsS100A9 null mice were used to investigate the role of S100A9 in aging-related pathologies. Artery rings were used to measure the functional characteristics of vascular with a pressurized myograph. Telomere length, Sirtuin activity, oxidative stress, and endothelial nitric oxide synthetase (eNOS) activity were used to elevate vascular senescence. Intraperitoneal glucose tolerance (IPGTT) and insulin sensitivity test (IST) were employed to investigate the effects of S100A9 on insulin resistance. Inflammation response was reflected by the concentration of inflammatory cytokines. The Toll-like receptor 4 (TLR4) and receptor for advanced glycation end products (RAGE) inhibitors were used to identify the downstream molecular mechanisms of S100A9 in aging-induced senescence in endothelial cells. ResultsS100A9 expression in vascular increased with aging in mice and humans. Deficiency of S100A9 alleviated vascular senescence in aged mice, as evidenced by increased telomere length, Sirtuin activity, and eNOS activity. Meanwhile, S100A9 knockout improved endothelium-dependent vasodilatation and endothelial continuity in aged mice. Moreover, the increased insulin resistance, oxidative stress, and inflammation were mitigated by S100A9 deletion in aged mice. In vitro, S100A9 induced senescence in endothelial cells, and that effect was blunted by TLR4 but not RAGE inhibitors. ConclusionThe present study suggested that S100A9 may contribute to aging-related pathologies and endothelial dysfunction via the TLR4 pathway. Therefore, targeting S100A9/TLR4 signaling pathway may represent a crucial therapeutic strategy to prevent age-related cardiovascular diseases.

Targeting p21-highly-expressing Endothelial Senescent Cells Prevent Vascular Dysfunction Induced by High-Fat Diet

BACKGROUND: Cardiovascular diseases are the leading cause of death worldwide. Overweight and obesity are strongly associated with comorbidities such as hypertension and insulin resistance, which collectively contribute to the development of cardiovascular disease. Although high-fat diet shows increased vascular senescence and vascular dysfunction, it remains unclear how obesity could induce cellular senescence and whether vascular dysfunction is associated with senescence of cells in the vasculature. p21 is one of the major regulators and most recognized cellular markers for senescent cells. Recent evidence demonstrated that high fat diet induces the accumulation of p21 high cells in the endothelial cells. However, the relationship between p21 high cells and vascular function is not identified yet. Therefore, this study investigated the linkage between vasodilation and p21 high cells in aging or high-fat diet-induced vascular dysfunction. METHODS: Five p21-Cre/+; +/+ (P) and p21-Cre/+; DTA/+ (PD) obese mice fed by high fat diet were administrated with tamoxifen for twice. Five P lean mice fed by normal chow were adopted as normal control. We previously demonstrated that p21high cells accumulate in obese P mice, and can be eliminated in obese PD mice by tamoxifen treatment. Using pressure myography, vasodilation in femoral arteries was assessed in response to flow-induced shear stress, acetylcholine (ACh), and sodium nitroprusside (SNP). Free Radical Production were measured by Amplex Red Assays. One-way ANOVAs with Bonferroni post-hoc were used to determine differences between groups (P < 0.05). RESULTS: Endothelium-dependent vasodilation was significantly attenuated in the old, induced by both flow (Lean P: 62 ± 4, Obese P: 23 ± 3 %; p < 0.05) and ACh (Lean P: 77 ± 4, Obese P: 35 ± 4 %; p < 0.05). However, the clearance of p21 high cells using tamoxifen enhanced vasodilatory function response to both flow (Obese P: 23 ± 3 %, Obese PD: 58 ± 3 %; p < 0.05) and ACh (Obese P: 35 ± 4 %, Obese PD: 70 ± 3 %; p < 0.05) while endothelium-independent vasodilation was not altered by high fat diet. Also, high fat diet increased free radical production, but the clearance of p21 high cells using tamoxifen attenuated free radical production (Lean P: 10.16 ± 0.41 pmol·s-1·mg-1; Obese P: 26.83 ± 0.54 pmol·s-1·mg-1; Obese PD: 12.23 ± 0.54 pmol·s-1·mg-1; P<0.05). CONCLUSION: These results demonstrated that p21high cells may play a causal role in vascular dysfunction with obesity and other chronic disease. Therefore, targeting p21high cells may enhance vasodilatory function through decreasing oxidative stress. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Parishin alleviates vascular ageing in mice by upregulation ofKlotho.

Senescence of vascular endothelial cells is the major risk of vascular dysfunction and disease among elderly people. Parishin, which is a phenolic glucoside derived from Gastrodia elata, significantly prolonged yeast lifespan. However, the action of parishin in vascular ageing remains poorly understood. Here, we treated human coronary artery endothelial cells (HCAEC) and naturally aged mice by parishin. Parishin alleviated HCAEC senescence and general age-related features in vascular tissue in naturally aged mice. Network pharmacology approach was applied to determine the compound-target networks of parishin. Our analysis indicated that parishin had a strong binding affinity for Klotho. Expression of Klotho, a protein of age-related declines, was upregulated by parishin in serum and vascular tissue in naturally aged mice. Furthermore, FoxO1, on Klotho/FoxO1 signalling pathway, was increased in the parishin-intervened group, accompanied by the downregulated phosphorylated FoxO1. Taken together, parishin can increase Klotho expression to alleviate vascular endothelial cell senescence and vascular ageing.

Oxidative Stress Induced Dysfunction of Protein Synthesis in 661W Mice Photoreceptor Cells.

Photoreceptor cells are highly susceptible to oxidative-stress-induced damage due to their high metabolic rate. Oxidative stress plays a key role in driving pathological events in several different ocular diseases, which lead to retinal degeneration and ultimately blindness. A growing number of studies have been performed to understand downstream events caused by ROS induced oxidative stress in photoreceptor cells; however, the underlying mechanisms of ROS toxicity are not fully understood. To shed light on ROS induced downstream pathological events, we employed a tandem mass tag (TMT) labelling-based quantitative mass-spectrometric approach to determine proteome changes in 661W photoreceptor cells following oxidative stress induction via the application of different concentrations of H2O2 at different time points. Overall, 5920 proteins were identified and quantified, and 450 differentially expressed proteins (DEPs) were identified, which were altered in a dose and time dependent manner in all treatment groups compared to the control group. These proteins were involved in several biological pathways, including spliceosome and ribosome response, activated glutathione metabolism, decreased ECM-receptor interaction, oxidative phosphorylation, abnormally regulated lysosome, apoptosis, and ribosome biogenesis. Our results highlighted ECM receptor interaction, oxidative phosphorylation and spliceosome pathways as the major targets of oxidative stress that might mediate vascular dysfunction and cellular senescence.

CXCL12 Inhibition Prevents Telomere Shortening and Repression of Telomerase Activity in Both Early and Late Post-menopausal Atherosclerosis via ABCA1 Upregulation

Vascular senescence is a key component in the initiation of atherosclerosis and its related cardiovascular disorders. C-X-C Motif Chemokine Ligand 12 (CXCL12), the CXC chemokine receptor 4 (CXCR4) ligand is a chemokine known to promote atherosclerosis. However, the role of telomeres in CXCL12-mediated senescence-induced atherosclerosis remains obscure. This study aimed to unravel the role of CXCL12 and its association with telomeres in the context of menopause-induced arterial senescence and atherosclerosis. Apoe–/– mice underwent bilateral ovariectomy (OVX) to simulate early and late postmenopausal (EPM) conditions (1 and 5 weeks post-OVX, respectively). POL5551, a selective CXCR4 antagonist, was administered as a continuous infusion (30 mg/kg/day in PBS) using a subcutaneously implanted osmotic minipump for two weeks. ATP binding cassette transporter A1 (ABCA1), a cholesterol efflux regulator was significantly downmodulated (p < 0.05), while NOD-, LRR- and pyrin domain-containing protein 3 (NLR) family pyrin domain containing 3 (NLRP3), inducible nitric oxide synthase (iNOS) and the inflammatory mediators were considerably enhanced (p < 0.05) in both EPM and LPM mice groups. Notably, atherosclerosis was more prominent in the EPM than in the LPM mice. However, POL5551 treatment effectively ameliorated the reduced ABCA1 expression and the increased inflammatory response. Hence, we propose that inhibition of CXCL12 proffers robust anti-senescent and anti-atherosclerotic effects.