Inflammatory Drivers of Cardiovascular Disease: Molecular Characterization of Senescent Coronary Vascular Smooth Muscle Cells

Functional deterioration of vascular mitochondrial and glycolytic capacity in the aortic rings of aged mice

Vascular ageing is associated with increased arterial stiffness and cardiovascular mortality that might be linked to altered vascular energy metabolism. The aim of this study was to establish a Seahorse XFe96 Analyzer-based methodology for the reliable, functional assessment of mitochondrial respiration and glycolysis in single murine aortic rings and to validate this functional assay by characterising alterations in vascular energy metabolism in aged mice. Healthy young and old C57BL/6 mice were used for the analyses. An optimised setup consisting of the Seahorse XFe96 Analyzer and Seahorse Spheroid Microplates was applied for the mitochondrial stress test and the glycolysis stress test on the isolated murine aortic rings, supplemented with analysis of NAD content in the aorta. To confirm the age-dependent stiffness of the vasculature, pulse wave velocity was measured in vivo. In addition, the activity of vascular nitric oxide synthase and vascular wall morphology were analysed ex vivo. The vascular ageing phenotype in old mice was confirmed by increased aortic stiffness, vascular wall remodelling, and nitric oxide synthase activity impairment. The rings of the aorta taken from old mice showed changes in vascular energy metabolism, including impaired spare respiratory capacity, maximal respiration, glycolysis, and glycolytic capacity, as well as a fall in the NAD pool. In conclusion, optimised Seahorse XFe96-based analysis to study energy metabolism in single aortic rings of murine aorta revealed a robust impairment of functional vascular respiratory and glycolytic capacity in old mice linked to NAD deficiency that coincided with age-related aortic wall remodelling and stiffness.

Differential responses to thrombospondin-1 and PDGF-BB in smooth muscle cells from atherosclerotic coronary arteries and internal thoracic arteries

Atherosclerosis is rare in internal thoracic arteries (ITA) even in patients with severe atherosclerotic coronary artery (ACA) disease. To explore cellular differences, ITA SMC from 3 distinct donors and ACA SMC from 3 distinct donors were grown to sub-confluence and growth arrested for 48 h. Proliferation and thrombospondin-1 (TSP1) production were determined using standard techniques. ITA SMC were larger, grew more slowly and survived more passages than ACA SMC. ACA SMC had a more pronounced proliferative response to 10% serum than ITA SMC. Both ACA SMC and ITA SMC proliferated in response to exogenous TSP1 (12.5 µg/ml and 25 µg/ml) and platelet derived growth factor-BB (PDGF-BB; 20 ng/ml) but TSP1- and PDGF-BB-induced proliferation were partially inhibited by anti-TSP1 antibody A4.1, microRNA-21(miR-21)-3p inhibitors and miR-21-5p inhibitors in each of the 3 ACA SMC lines, but not in any of the ITA SMC lines. PDGF-BB stimulated TSP1 production in ACA SMC but not in ITA SMC but there was no increase in TSP1 levels in conditioned media in either SMC type. In summary, there are significant differences in morphology, proliferative capacity and in responses to TSP1 and PDGF-BB in SMC derived from ITA compared to SMC derived from ACA.

Identification of key genes and biological pathways associated with vascular aging in diabetes based on bioinformatics and machine learning

Vascular aging exacerbates diabetes-associated vascular damage, a major cause of microvascular and macrovascular complications. This study aimed to elucidate key genes and pathways underlying vascular aging in diabetes using integrated bioinformatics and machine learning approaches. Gene expression datasets related to vascular smooth muscle cell (VSMC) senescence and diabetic vascular aging were analyzed. Differential expression analysis identified 428 genes associated with VSMC senescence. Functional enrichment revealed their involvement in cellular senescence, ECM-receptor interaction, PI3K-Akt and AGE-RAGE signaling pathways. Further analysis of diabetic vascular aging datasets revealed 52 differentially expressed genes, enriched in AMPK signaling, AGE-RAGE signaling, cellular senescence, and VEGF signaling pathways. Machine learning algorithms, including LASSO regression and SVM-RFE, pinpointed six key genes: TFB1M, FOXRED2, LY75, DALRD3, PI4K2B, and NDOR1. Immune cell infiltration analysis demonstrated correlations between diabetic vascular aging, the identified key genes, and infiltration levels of plasma cells, M1 macrophages, CD8+ T cells, eosinophils, and regulatory T cells. In conclusion, this study identified six pivotal genes (TFB1M, FOXRED2, LY75, DALRD3, PI4K2B, and NDOR1) closely associated with diabetic vascular aging through integrative bioinformatics and machine learning approaches. These genes are linked to alterations in the immune microenvironment during diabetic vascular aging. This study provides a reference and basis for molecular mechanism research, biomarker mining, and diagnosis and treatment evaluation of diabetes-related vascular aging.

Vascular Aging and Atherosclerosis: A Perspective on Aging

Vascular aging (VA) is recognized as a pivotal factor in the development and progression of atherosclerosis (AS). Although various epidemiological and clinical research has demonstrated an intimate connection between aging and AS, the candidate mechanisms still require thorough examination. This review adopts an aging-centric perspective to deepen the comprehension of the intricate relationship between biological aging, vascular cell senescence, and AS. Various aging-related physiological factors influence the physical system's reactions, including oxygen radicals, inflammation, lipids, angiotensin II, mechanical forces, glucose levels, and insulin resistance. These factors cause endothelial dysfunction, barrier damage, sclerosis, and inflammation for VA and promote AS via distinct or shared pathways. Furthermore, the increase of senescent cells inside the vascular tissues, caused by genetic damage, dysregulation, secretome changes, and epigenetic modifications, might be the primary cause of VA.

PURPL and NEAT1 Long Non-Coding RNAs Are Modulated in Vascular Smooth Muscle Cell Replicative Senescence

Cellular senescence is characterized by proliferation and migration exhaustion, senescence-associated secretory phenotype (SASP), and oxidative stress. Senescent vascular smooth muscle cells (VSMCs) contribute to cardiovascular diseases and atherosclerotic plaque instability. Since there are no unanimously agreed senescence markers in human VSMCs, to improve our knowledge, we looked for new possible senescence markers. To this end, we first established and characterized a model of replicative senescence (RS) in human aortic VSMCs. Old cells displayed several established senescence-associated markers. They stained positive for the senescence-associated β-galactosidase, showed a deranged proliferation rate, a dramatically reduced expression of PCNA, an altered migratory activity, increased levels of TP53 and cell-cycle inhibitors p21/p16, and accumulated in the G1 phase. Old cells showed an altered cellular and nuclear morphology, downregulation of the expression of LMNB1 and HMGB1, and increased expression of SASP molecules (IL1β, IL6, IL8, and MMP3). In these senescent VSMCs, among a set of 12 manually selected long non-coding RNAs (lncRNAs), we detected significant upregulation of PURPL and NEAT1. We observed also, for the first time, increased levels of RRAD mRNA. The detection of modulated levels of RRAD, PURPL, and NEAT1 during VSMC senescence could be helpful for future studies on potential anti-aging factors.

Vascular dysfunction caused by loss of Brn-3b/POU4F2 transcription factor in aortic vascular smooth muscle cells is linked to deregulation of calcium signalling pathways

Phenotypic and functional changes in vascular smooth muscle cells (VSMCs) contribute significantly to cardiovascular diseases (CVD) but factors driving early adverse vascular changes are poorly understood. We report on novel and important roles for the Brn-3b/POU4F2 (Brn-3b) transcription factor (TF) in controlling VSMC integrity and function. Brn-3b protein is expressed in mouse aorta with localisation to VSMCs. Male Brn-3b knock-out (KO) aortas displayed extensive remodelling with increased extracellular matrix (ECM) deposition, elastin fibre disruption and small but consistent narrowing/coarctation in the descending aortas. RNA sequencing analysis showed that these effects were linked to deregulation of genes required for calcium (Ca2+) signalling, vascular contractility, sarco-endoplasmic reticulum (S/ER) stress responses and immune function in Brn-3b KO aortas and validation studies confirmed changes in Ca2+ signalling genes linked to increased intracellular Ca2+ and S/ER Ca2+ depletion [e.g. increased, Cacna1d Ca2+ channels; ryanodine receptor 2, (RyR2) and phospholamban (PLN) but reduced ATP2a1, encoding SERCA1 pump] and chaperone proteins, Hspb1, HspA8, DnaJa1 linked to increased S/ER stress, which also contributes to contractile dysfunction. Accordingly, vascular rings from Brn-3b KO aortas displayed attenuated contractility in response to KCl or phenylephrine (PE) while Brn-3b KO-derived VSMC displayed abnormal Ca2+ signalling following ATP stimulation. This data suggests that Brn-3b target genes are necessary to maintain vascular integrity /contractile function and deregulation upon loss of Brn-3b will contribute to contractile dysfunction linked to CVD.

Senescence-Associated Secretory Phenotype of Cardiovascular System Cells and Inflammaging: Perspectives of Peptide Regulation

A senescence-associated secretory phenotype (SASP) and a mild inflammatory response characteristic of senescent cells (inflammaging) form the conditions for the development of cardiovascular diseases: atherosclerosis, coronary heart disease, and myocardial infarction. The purpose of the review is to analyze the pool of signaling molecules that form SASP and inflammaging in cells of the cardiovascular system and to search for targets for the action of vasoprotective peptides. The SASP of cells of the cardiovascular system is characterized by a change in the synthesis of anti-proliferative proteins (p16, p19, p21, p38, p53), cytokines characteristic of inflammaging (IL-1α,β, IL-4, IL-6, IL-8, IL-18, TNFα, TGFβ1, NF-κB, MCP), matrix metalloproteinases, adhesion molecules, and sirtuins. It has been established that peptides are physiological regulators of body functions. Vasoprotective polypeptides (liraglutide, atrial natriuretic peptide, mimetics of relaxin, Ucn1, and adropin), KED tripeptide, and AEDR tetrapeptide regulate the synthesis of molecules involved in inflammaging and SASP-forming cells of the cardiovascular system. This indicates the prospects for the development of drugs based on peptides for the treatment of age-associated cardiovascular pathology.

Proteomics, dietary intake, and changes in cardiometabolic health within a behavioral weight-loss intervention: A pilot study

OBJECTIVE

Identifying associations among circulating proteins, dietary intakes, and clinically relevant indicators of cardiometabolic health during weight loss may elucidate biologically relevant pathways affected by diet, allowing for an incorporation of precision nutrition approaches when designing future interventions. This study hypothesized that plasma proteins would be associated with diet and cardiometabolic health indicators within a behavioral weight-loss intervention.

METHODS

This secondary data analysis included participants (n = 20, mean [SD], age: 40.1 [9.5] years, BMI: 34.2 [4.0] kg/m2 ) who completed a 1-year behavioral weight-loss intervention. Cardiovascular disease-related plasma proteins, diet, and cardiometabolic health indicators were evaluated at baseline and 3 months. Associations were determined via linear regression and integrated networks created using Visualization Of LineAr Regression Elements (VOLARE).

RESULTS

A total of 16 plasma proteins were associated with ≥1 diet or health indicator at baseline (p < 0.001); changes in 42 proteins were associated with changes in diet or health indicators from baseline to 3 months (p < 0.005). Baseline tumor necrosis factor receptor superfamily member 10C (TNFRSF10C) was associated with intakes of dark green vegetables (r = -0.712), and fatty acid-binding protein 4 (FABP4) was associated with intakes of unsweetened coffee (r = -0.689). Changes in refined-grain intakes were associated with changes in scavenger receptor cysteine-rich type 1 protein M130 (CD163; r = 0.725), interleukin-1 receptor type 1 (IL1R-T1; r = 0.624), insulin (r = 0.656), and triglycerides (r = 0.648).

CONCLUSIONS

Circulating cardiovascular disease-related proteins were associated with diet and cardiometabolic health indicators prior to and in response to weight loss.

Resveratrol alleviates Ang II-induced vascular smooth muscle cell senescence by upregulating E2F1/SOD2 axis

Background

Vascular smooth muscle cells (VSMCs) senescence is a crucial factor relevant to accelerate cardiovascular diseases. Resveratrol (RES) has been reported that could obstruct vascular senescence. However, the detailed molecular mechanisms of RES in VSMCs senescence are still indistinct and deserve further investigations.

Methods and Results

In this study, VSMCs were treated with 100 nM angiotensin II (Ang II) for 3 days and then followed with a range of different concentrations of RES (0.5, 5, 15, 25, 35, 50 μM), and 25 μM of RES was chose for following experiments. We found that the E2F1 and SOD2 expressions were reduced in Ang II-induced VSMCs. RES treatment impeded Ang II-induced oxidative stress and mitochondrial dysfunction through elevating E2F1 and SOD2 expression, thereby alleviating VSMCs senescence. Additionally, E2F1 knockdown reversed the protective effects of RES on VSMCs senescence caused by Ang II administration. Ch-IP assay and dual luciferase reporter gene assay validated that E2F1 could bind to the promoter region of SOD2. Furthermore, E2F1 or SOD2 overexpression blocked Ang II-induced on VSMCs senescence.

Conclusion

In conclusion, RES mitigated Ang II-induced VSMCs senescence by suppressing oxidative stress and mitochondrial dysfunction through activating E2F1/SOD2 axis. Our study disclosed that RES might be a potential drug and the axis of its regulatory mechanism might be therapeutic targets for postponing vascular senescence.

Morin Inhibits Dox-Induced Vascular Inflammation By Regulating PTEN/AKT/NF-κB Pathway

The side effects of doxorubicin (Dox) may influence the long-term survival of patients with malignancies. Therefore, it is necessary to clarify the mechanisms generating these side effects induced by Dox and identify effective therapeutic strategies. Here, we found that interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-alpha (TNF-α) levels were significantly increased in vascular tissues of Dox-treated mice and Dox-treated vascular smooth muscle cells (VSMCs). Furthermore, we revealed that Dox downregulated the phosphatase and tension homology deleted on chromosome 10 (PTEN) level while upregulated p-AKT and p65 level in VSMCs in vitro. Overexpression of PTEN in VSMCs partly reversed Dox-induced inflammation. Importantly, we demonstrated that Morin could inhibit Dox-induced inflammation by facilitating an increase of PTEN, thus inhibiting the activation of protein kinase B (AKT)/nuclear factor kappa B (NF-κB)/pathway. Additionally, we showed that Morin could reduce the miR-188-5p level, which was increased in Dox-treated VSMCs. Inhibition of miR-188-5p suppressed Dox-induced vascular inflammation in vitro. In conclusion, Morin reduced the Dox-induced vascular inflammatory by moderating the miR-188-5p/PTEN/AKT/NF-κB pathway, indicating that Morin might be a therapeutic agent for overcoming the Dox-induced vascular inflammation.

The multifaceted role of the SASP in atherosclerosis: from mechanisms to therapeutic opportunities

BACKGROUND

The global population of older individuals is growing, and ageing is a key risk factor for atherosclerotic cardiovascular diseases. Abnormal accumulation of senescent cells can cause potentially deleterious effects on the organism with age. As a vital marker of cellular senescence, the senescence-associated secretory phenotype (SASP) is a novel mechanism to link cellular senescence with atherosclerosis.

MAIN BODY

In this review, we concretely describe the characteristics of the SASP and its regulation mechanisms. Importantly, we provide novel perspectives on how the SASP can promote atherosclerosis. The SASP from different types of senescent cells have vital roles in atherosclerosis progression. As a significant mediator of the harmful effects of senescent cells, it can play a pro-atherogenic role by producing inflammation and immune dysfunction. Furthermore, the SASP can deliver senescence signals to the surrounding vascular cells, gradually contributing to the development of atherosclerosis. Finally, we focus on a variety of novel therapeutic strategies aimed to reduce the burden of atherosclerosis in elderly individuals by targeting senescent cells and inhibiting the regulatory mechanisms of the SASP.

CONCLUSION

This review systematically summarizes the multiple roles of the SASP in atherosclerosis and can contribute to the exploration of new therapeutic opportunities.

Preservation of Smooth Muscle Cell Integrity and Function: A Target for Limiting Abdominal Aortic Aneurysm Expansion?

(1) Abdominal aortic aneurysm (AAA) is a silent, progressive disease with significant mortality from rupture. Whilst screening programmes are now able to detect this pathology early in its development, no therapeutic intervention has yet been identified to halt or retard aortic expansion. The inability to obtain aortic tissue from humans at early stages has created a necessity for laboratory models, yet it is essential to create a timeline of events from EARLY to END stage AAA progression. (2) We used a previously validated ex vivo porcine bioreactor model pre-treated with protease enzyme to create “aneurysm” tissue. Mechanical properties, histological changes in the intact vessel wall, and phenotype/function of vascular smooth muscle cells (SMC) cultured from the same vessels were investigated. (3) The principal finding was significant hyperproliferation of SMC from EARLY stage vessels, but without obvious histological or SMC aberrancies. END stage tissue exhibited histological loss of α-smooth muscle actin and elastin; mechanical impairment; and, in SMC, multiple indications of senescence. (4) Aortic SMC may offer a therapeutic target for intervention, although detailed studies incorporating intervening time points between EARLY and END stage are required. Such investigations may reveal mechanisms of SMC dysfunction in AAA development and hence a therapeutic window during which SMC differentiation could be preserved or reinstated.

A potential role of autophagy-mediated vascular senescence in the pathophysiology of HFpEF

Heart failure with preserved ejection fraction (HFpEF) is one of the most complex and most prevalent cardiometabolic diseases in aging population. Age, obesity, diabetes, and hypertension are the main comorbidities of HFpEF. Microvascular dysfunction and vascular remodeling play a major role in its development. Among the many mechanisms involved in this process, vascular stiffening has been described as one the most prevalent during HFpEF, leading to ventricular-vascular uncoupling and mismatches in aged HFpEF patients. Aged blood vessels display an increased number of senescent endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). This is consistent with the fact that EC and cardiomyocyte cell senescence has been reported during HFpEF. Autophagy plays a major role in VSMCs physiology, regulating phenotypic switch between contractile and synthetic phenotypes. It has also been described that autophagy can regulate arterial stiffening and EC and VSMC senescence. Many studies now support the notion that targeting autophagy would help with the treatment of many cardiovascular and metabolic diseases. In this review, we discuss the mechanisms involved in autophagy-mediated vascular senescence and whether this could be a driver in the development and progression of HFpEF.

Senescence-Associated Secretory Phenotype as a Hinge Between Cardiovascular Diseases and Cancer

Overlapping risks for cancer and cardiovascular diseases (CVD), the two leading causes of mortality worldwide, suggest a shared biology between these diseases. The role of senescence in the development of cancer and CVD has been established. However, its role as the intersection between these diseases remains unclear. Senescence was originally characterized by an irreversible cell cycle arrest after a high number of divisions, namely replicative senescence (RS). However, it is becoming clear that senescence can also be instigated by cellular stress, so-called stress-induced premature senescence (SIPS). Telomere shortening is a hallmark of RS. The contribution of telomere DNA damage and subsequent DNA damage response/repair to SIPS has also been suggested. Although cellular senescence can mediate cell cycle arrest, senescent cells can also remain metabolically active and secrete cytokines, chemokines, growth factors, and reactive oxygen species (ROS), so-called senescence-associated secretory phenotype (SASP). The involvement of SASP in both cancer and CVD has been established. In patients with cancer or CVD, SASP is induced by various stressors including cancer treatments, pro-inflammatory cytokines, and ROS. Therefore, SASP can be the intersection between cancer and CVD. Importantly, the conventional concept of senescence as the mediator of cell cycle arrest has been challenged, as it was recently reported that chemotherapy-induced senescence can reprogram senescent cancer cells to acquire “stemness” (SAS: senescence-associated stemness). SAS allows senescent cancer cells to escape cell cycle arrest with strongly enhanced clonogenic growth capacity. SAS supports senescent cells to promote both cancer and CVD, particularly in highly stressful conditions such as cancer treatments, myocardial infarction, and heart failure. As therapeutic advances have increased overlapping risk factors for cancer and CVD, to further understand their interaction may provide better prevention, earlier detection, and safer treatment. Thus, it is critical to study the mechanisms by which these senescence pathways (SAS/SASP) are induced and regulated in both cancer and CVD.

Omarigliptin Prevents TNF-α-Induced Cellular Senescence in Rat Aorta Vascular Smooth Muscle Cells

Cellular senescence is one of the most significant factors involved in aging and age-related diseases. Senescence of vascular smooth muscle cells (VSMCs) adversely affects the function of the cardiovascular system and contributes to the development of atherosclerosis, hypertension, and other cardiovascular diseases. Glucagon-like peptide-1 (GLP-1) is an important incretin hormone involved in insulin release and vascular tone. GLP-1 is quickly degraded by the enzyme dipeptidyl peptidase-4 (DPP-4). Omarigliptin is a new DPP-4 inhibitor that has demonstrated anti-inflammatory and antioxidative stress properties. In the present study, we investigated the effects of the selective DPP-4 inhibitor omarigliptin (OMG) on VSMCs exposed to insult from tumor necrosis factor-α (TNF-α), one of the main inflammatory signaling molecules involved in cellular senescence. We found that OMG could suppress TNF-α-induced expression of pro-inflammatory cytokines (interleukin-1β (IL-1β), IL-6, and IL-8) and inhibit oxidative stress by reducing the production of H2O2 and protein carbonyl. OMG ameliorated the increase in senescence-associated β-galactosidase (SA-β-gal) and telomerase activity induced by TNF-α. The plasminogen activator inhibitor-1 (PAI-1)/p53/p21 pathway is a key inducer of cellular senescence. OMG ameliorated the acetylation of p53 at lysine 382 (K382) and subsequent activation of p21 via inhibition of PAI-1. Importantly, our experiments revealed that blockage of silent information-regulator 1 (SIRT1) abolished the inhibitory effects of OMG on p53 acetylation, SA-β-gal activity, and telomerase activity in VSMCs. These results suggest that OMG may have the potential to delay or prevent the progression of age-related cardiovascular diseases by modulating the activity of SIRT1.

Genotyping of interleukins-18 promoters and their correlation with coronary artery stenosis in Saudi population

BACKGROUND

Complex coronary atherosclerotic lesions often lead to coronary occlusion, clinically represented as a single-vessel disease (SVD) and multivessel disease (MVD). These occlusions could hinder the blood flow in coronary arteries that affects appropriate management of the CVD. The current study intended to genotype interleukin (IL)-18 promoter's hotspots (rs187238, rs1946518, and rs1946519) and their possible association with coronary artery stenosis.

MATERIAL AND METHODS

The IL-18 promoter genotyping was performed by the Sanger method along with the examination of biochemical parameters in 125 study subjects categorized into three groups, viz. controls, SVD and MVD.

RESULTS

The current study observed a significant association of diabetes, hypertension, and dyslipidemia between the studied group's viz. healthy controls, SVD, and MVD. Fasting blood sugar and glycosylated hemoglobin (HBA1C) were also significantly enhanced from 4.82 vs. 8.01 and 4.33 vs. 8.27, in SVD, and MVD respectively. Despite the visible differences in the pattern of genotypic and allelic expressions, the current study did not show any statistically significant correlation with IL-18 promoter polymorphism at its hotspots with controls, SVD, and MVD subjects. The only exception of the above results was the distribution of allelic frequency at the rs1946519 hotspot, where a significant change (P < 0.05) was observed.

CONCLUSION

This study is of additional value to our previous reports, revealing the pattern of genotypes and allelic frequency of IL-18 promoters in a small cohort of Saudi ethnicity. Further investigations on larger sample size are recommended to envisage the presence of functional mutations in the IL-18 gene that could establish or rule out the possible association of IL-18 polymorphism with SVD and MVD.

Efficacy and limitations of senolysis in atherosclerosis

Aims

Traditional markers of cell senescence including p16, Lamin B1, and senescence-associated beta galactosidase (SAβG) suggest very high frequencies of senescent cells in atherosclerosis, while their removal via ‘senolysis’ has been reported to reduce atherogenesis. However, selective killing of a variety of different cell types can exacerbate atherosclerosis. We therefore examined the specificity of senescence markers in vascular smooth muscle cells (VSMCs) and the effects of genetic or pharmacological senolysis in atherosclerosis.

Methods and results

We examined traditional senescence markers in human and mouse VSMCs in vitro, and in mouse atherosclerosis. p16 and SAβG increased and Lamin B1 decreased in replicative senescence and stress-induced premature senescence (SIPS) of cultured human VSMCs. In contrast, mouse VSMCs undergoing SIPS showed only modest p16 up-regulation, and proliferating mouse monocyte/macrophages also expressed p16 and SAβG. Single cell RNA-sequencing (scRNA-seq) of lineage-traced mice showed increased p16 expression in VSMC-derived cells in plaques vs. normal arteries, but p16 localized to Stem cell antigen-1 (Sca1)⁺ or macrophage-like populations. Activation of a p16-driven suicide gene to remove p16⁺ vessel wall- and/or bone marrow-derived cells increased apoptotic cells, but also induced inflammation and did not change plaque size or composition. In contrast, the senolytic ABT-263 selectively reduced senescent VSMCs in culture, and markedly reduced atherogenesis. However, ABT-263 did not reduce senescence markers in vivo, and significantly reduced monocyte and platelet counts and interleukin 6 as a marker of systemic inflammation.

Conclusions

We show that genetic and pharmacological senolysis have variable effects on atherosclerosis, and may promote inflammation and non-specific effects respectively. In addition, traditional markers of cell senescence such as p16 have significant limitations to identify and remove senescent cells in atherosclerosis, suggesting that senescence studies in atherosclerosis and new senolytic drugs require more specific and lineage-restricted markers before ascribing their effects entirely to senolysis.

Reconstruction of the miR-506-Quaking axis in Idiopathic Pulmonary Fibrosis using integrative multi-source bioinformatics

The family of RNA-binding proteins (RBP) functions as a crucial regulator of multiple biological processes and diseases. However, RBP function in the clinical setting of idiopathic pulmonary fibrosis (IPF) is still unknown. We developed a practical in silico screening approach for the characterization of RBPs using multi-sources data information and comparative molecular network bioinformatics followed by wet-lab validation studies. Data mining of bulk RNA-Sequencing data of tissues of patients with IPF identified Quaking (QKI) as a significant downregulated RBP. Cell-type specific expression was confirmed by single-cell RNA-Sequencing analysis of IPF patient data. We systematically analyzed the molecular interaction network around QKI and its functional interplay with microRNAs (miRs) in human lung fibroblasts and discovered a novel regulatory miR-506-QKI axis contributing to the pathogenesis of IPF. The in silico results were validated by in-house experiments applying model systems of miR and lung biology. This study supports an understanding of the intrinsic molecular mechanisms of IPF regulated by the miR-506-QKI axis. Initially applied to human lung disease, the herein presented integrative in silico data mining approach can be adapted to other disease entities, underlining its practical relevance in RBP research.

The Role of Mitochondria in Immune-Cell-Mediated Tissue Regeneration and Ageing

During tissue injury events, the innate immune system responds immediately to alarms sent from the injured cells, and the adaptive immune system subsequently joins in the inflammatory reaction. The control mechanism of each immune reaction relies on the orchestration of different types of T cells and the activators, antigen-presenting cells, co-stimulatory molecules, and cytokines. Mitochondria are an intracellular signaling organelle and energy plant, which supply the energy requirement of the immune system and maintain the system activation with the production of reactive oxygen species (ROS). Extracellular mitochondria can elicit regenerative effects or serve as an activator of the immune cells to eliminate the damaged cells. Recent clarification of the cytosolic escape of mitochondrial DNA triggering innate immunity underscores the pivotal role of mitochondria in inflammation-related diseases. Human mesenchymal stem cells could transfer mitochondria through nanotubular structures to defective mitochondrial DNA cells. In recent years, mitochondrial therapy has shown promise in treating heart ischemic events, Parkinson's disease, and fulminating hepatitis. Taken together, these results emphasize the emerging role of mitochondria in immune-cell-mediated tissue regeneration and ageing.

MiR-665 Regulates Vascular Smooth Muscle Cell Senescence by Interacting With LncRNA GAS5/SDC1

Background: Vascular aging is considered a special risk factor for cardiovascular diseases, and vascular smooth muscle cells (VSMCs) play a major role in aging-related vascular remodeling and in the pathological process of atherosclerosis. Recent research has reported that long non-coding RNA/microRNA (lncRNA/miRNA) is a critical regulator of cellular senescence. However, the role and mechanism of lncRNA GAS5/miR-665 axis in VSMC senescence remain incompletely understood. Methods: Cellular senescence was evaluated using senescence-associated β-gal activity, the NAD+/NADH ratio, and by immunofluorescence staining of γH2AX immunofluorescence. Differentially expressed miRNAs (DEMs) were identified by miRNA microarray assays and subsequently validated by quantitative real-time PCR (qRT-PCR). A dual luciferase reporter assay was conducted to confirm the binding of lncRNA GAS5 and miR-665 as well as miR-665 and syndecan 1 (SDC1). Serum levels of miR-665, lncRNA GAS5, and SDC1 in 93 subjects were detected by qRT-PCR. The participants were subdivided into control, aging, and early vascular aging (EVA) groups, and their brachial-ankle pulse wave velocity (baPWV) was measured. Results: A total of 20 overlapping DEMs were identified in young and old VSMCs via microarray analysis. MiR-665 showed a significant alteration and, therefore, was selected for further analysis. Upregulation of miR-665 was found in aging VSMCs, and downregulation of miR-665 caused an inhibition of VSMCs senescence. Subsequently, the dual luciferase reporter assay determined the binding site of miR-665 with the 3'-UTR of lncRNA GAS5 and SDC1. Increased expression of lncRNA GAS5 expression inhibited the miR-665 level and VSMC senescence. However, as shown in rescue experiment results, either miR-665 overexpression or SDC1 knockdown significantly reversed the effects of lncRNA GAS5 on VSMC senescence. Finally, compared with that of the control group, miR-665 was highly expressed in serum samples in the aging and EVA groups, especially in the EVA groups. On the contrary, serum levels of lncRNA GAS5 and SDC1 were lower in these two groups. Collectively, in the aging and EVA groups, miR-665 expression was negatively correlated with lncRNA GAS5 and SDC1 expression. Conclusion: miR-665 inhibition functions as a vital modulator of VSMC senescence by negatively regulating SDC1, which is achieved by lncRNA GAS5 that sponges miR-665. Our findings may provide a new treatment strategy for aging-related cardiovascular diseases.

The Role of miRNA-146a and Proinflammatory Cytokines in Carotid Atherosclerosis

The aim of this study was to investigate the expression and significance of miRNA-146a in peripheral blood of patients with carotid atherosclerosis (CAS). Patients with CAS were selected as the stenosis (CAS) group (n = 180). According to the degree of stenosis, they were divided into the mild stenosis group (MS group, n = 64), moderate stenosis group (M group, n = 62 cases), and severe stenosis group (SS group, n = 54). According to the plaque type, patients were divided into a stable plaque group (SP group, n = 96) and a vulnerable plaque group (VP group, n = 84). Patients without CAS represented the normal group (n = 90). The expression levels of miRNA-146a as well as IL-6 and TNF-α in peripheral blood were detected by RT-PCR and ELISA, respectively. The expression levels of miRNA-146a, IL-6, and TNF-α in the CAS group were higher than those in the normal group and positively correlated with the degree of stenosis and plaque vulnerability. The expression levels of miRNA-146a, IL-6, and TNF-α in the stable plaque group were lower than those in the vulnerable plaque group. The area under the curve of miRNA-146a predicting the vulnerability of plaques was significant at 0.641. The expression level of miRNA-146a in the CAS group was positively correlated with IL-6 and TNF-α levels. Our results indicate that miRNA-146a may participate in the occurrence and development of CAS by regulating the expression of IL-6 and TNF-α, which may be potential biomarkers of CAS.

Cytotoxicity and Potential Pathway to Vascular Smooth Muscle Cells Induced by PM2.5 Emitted from Raw Coal Chunks and Clean Coal Combustion

Coal combustion emits a large amount of PM_2.5 (particulate matters with aerodynamic diameters less than 2.5 μm) and causes adverse damages to the cardiovascular system. In this study, emissions from anthracite and bitumite were examined. Red mud (RM) acts as an additive and is mixed in coal briquettes with a content of 0-10% as a single variable to demonstrate the reduction in the PM_2.5 emissions. Burnt in a regulated combustion chamber, the 10% RM-containing bitumite and anthracite briquettes showed 52.3 and 18.6% reduction in PM_2.5, respectively, compared with their chunk coals. Lower cytotoxicity (in terms of oxidative stresses and inflammation factors) was observed for PM_2.5 emitted from the RM-containing briquettes than those from non-RM briquettes, especially for the bitumite groups. Besides, the results of western blotting illustrated that the inhibition of NF-κB and MAPK was the potential pathway for the reduction of cytokine levels by the RM addition. The regression analyses further demonstrated that the reduction was attributed to the lower emissions of transition metals (i.e., Mn) and PAHs (i.e., acenaphthene). This pilot study provides solid evidence for the cytotoxicity to vascular smooth muscle cells induced by PM_2.5 from coal combustion and potential solutions for reducing the emission of toxic pollutants from human health perspectives.

Targeting Molecular Mechanism of Vascular Smooth Muscle Senescence Induced by Angiotensin II, A Potential Therapy via Senolytics and Senomorphics

Cardiovascular disease (CVD) is a prevalent issue in the global aging population. Premature vascular aging such as elevated arterial stiffness appears to be a major risk factor for CVD. Vascular smooth muscle cells (VSMCs) are one of the essential parts of arterial pathology and prone to stress-induced senescence. The pervasiveness of senescent VSMCs in the vasculature increases with age and can be further expedited by various stressing events such as oxidative stress, mitochondria dysfunction, endoplasmic reticulum stress, and chronic inflammation. Angiotensin II (AngII) can induce many of these responses in VSMCs and is thus considered a key regulator of VSMC senescence associated with CVD. Understanding the precise mechanisms and consequences of senescent cell accumulation may uncover a new generation of therapies including senolytic and senomorphic compounds against CVD. Accordingly, in this review article, we discuss potential molecular mechanisms of VSMC senescence such as those induced by AngII and the therapeutic manipulations of senescence to control age-related CVD and associated conditions such as by senolytic.

Comprehensive Bioinformatics Identifies Key microRNA Players in ATG7-Deficient Lung Fibroblasts

BACKGROUND

Deficient autophagy has been recently implicated as a driver of pulmonary fibrosis, yet bioinformatics approaches to study this cellular process are lacking. Autophagy-related 5 and 7 (ATG5/ATG7) are critical elements of macro-autophagy. However, an alternative ATG5/ATG7-independent macro-autophagy pathway was recently discovered, its regulation being unknown. Using a bioinformatics proteome profiling analysis of ATG7-deficient human fibroblasts, we aimed to identify key microRNA (miR) regulators in autophagy.

METHOD

We have generated ATG7-knockout MRC-5 fibroblasts and performed mass spectrometry to generate a large-scale proteomics dataset. We further quantified the interactions between various proteins combining bioinformatics molecular network reconstruction and functional enrichment analysis. The predicted key regulatory miRs were validated via quantitative polymerase chain reaction.

RESULTS

The functional enrichment analysis of the 26 deregulated proteins showed decreased cellular trafficking, increased mitophagy and senescence as the major overarching processes in ATG7-deficient lung fibroblasts. The 26 proteins reconstitute a protein interactome of 46 nodes and miR-regulated interactome of 834 nodes. The miR network shows three functional cluster modules around miR-16-5p, miR-17-5p and let-7a related to multiple deregulated proteins. Confirming these results in a biological setting, serially passaged wild-type and autophagy-deficient fibroblasts displayed senescence-dependent expression profiles of miR-16-5p and miR-17-5p.

CONCLUSIONS

We have developed a bioinformatics proteome profiling approach that successfully identifies biologically relevant miR regulators from a proteomics dataset of the ATG-7-deficient milieu in lung fibroblasts, and thus may be used to elucidate key molecular players in complex fibrotic pathological processes. The approach is not limited to a specific cell-type and disease, thus highlighting its high relevance in proteome and non-coding RNA research.