p53 expression in human carotid atheroma is significantly related to plaque instability and clinical manifestations

Oxysterols in Vascular Cells and Role in Atherosclerosis

Atherosclerosis is a major cardiovascular complication of diseases associated with elevated oxidative stress such as type 2 diabetes and metabolic syndrome. In these situations, low-density lipoproteins (LDL) undergo oxidation. Oxidized LDL displays proatherogenic activities through multiple and complex mechanisms which lead to dysfunctions of vascular cells (endothelial cells, smooth muscle cells, and macrophages). Oxidized LDLs are enriched in oxidized products of cholesterol called oxysterols formed either by autoxidation, enzymatically, or by both mechanisms. Several oxysterols have been shown to accumulate in atheroma plaques and to play a key role in atherogenesis. Depending on the type of oxysterols, various biological effects are exerted on vascular cells to regulate the formation of macrophage foam cells, endothelial integrity, adhesion and transmigration of monocytes, plaque progression, and instability. Most of these effects are linked to the ability of oxysterols to induce cellular oxidative stress and cytotoxicity mainly through apoptosis and proinflammatory mediators. Like for excess cholesterol, high-density lipoproteins (HDL) can exert antiatherogenic activity by stimulating the efflux of oxysterols that have accumulated in foamy macrophages.

Interleukin-35 Mitigates ox-LDL-Induced Proatherogenic Effects via Modulating miRNAs Associated with Coronary Artery Disease (CAD)

PURPOSE

Recent emergence of miRNAs as important regulators of processes involving lesion formation and regression has highlighted miRNAs as potent therapeutic targets for the treatment of atherosclerosis. Few studies have reported the atheroprotective role of IL-35, a novel immunosuppressive and anti-inflammatory cytokine; however, miRNA-dependent regulation underlying the anti-atherosclerotic potential of IL-35 remains elusive.

METHODS

THP-1 macrophages were incubated with human recombinant IL-35 (rIL-35) either in the presence or absence of ox-LDL. qRT-PCR was conducted to validate the expression levels of previously identified miRNAs including miR-197-5p, miR-4442, miR-324-3p, miR-6879-5p, and miR-6069 that were differentially expressed in peripheral blood mononuclear cells of coronary artery disease (CAD) patients vs. controls. Additionally, bioinformatic analysis was performed to predict miRNA-associated targets and their corresponding functional significance in CAD.

RESULTS

Exogenous IL-35 significantly decreased the average area of ox-LDL-stimulated macrophages, indicating the inhibitory effect of IL-35 on lipid-laden foam cell formation. Furthermore, rIL-35 treatment alleviated the ox-LDL-mediated atherogenic effects by modulating the expression levels of aforementioned CAD-associated miRNAs in the cultured macrophages. Moreover, functional enrichment analysis of these miRNA-related targets revealed their role in the molecular processes affecting different stages of atheroslerotic plaque development, such as macrophage polarization, T cell suppression, lipoprotein metabolism, foam cell formation, and iNOS-mediated inflammation.

CONCLUSION

Our observations uncover the novel role of IL-35 as an epigenetic modifier as it influences the expression level of miRNAs implicated in the pathogenesis of atherosclerosis. Thus, IL-35 cytokine therapy-mediated miRNA targeting could be an effective therapeutic strategy against the development of early atheromas in asymptomatic high-risk CAD patients.

Senescence in tissue samples of humans with age-related diseases: A systematic review

BACKGROUND

Higher numbers of senescent cells have been implicated in age-related disease pathologies. However, whether different diseases have different senescent phenotypes is unknown. Here we provide a systematic overview of the current available evidence of senescent cells in age-related diseases pathologies in humans and the markers currently used to detect senescence levels in humans.

METHODS

PubMed, Web of Science and EMBASE were systematically searched from inception to the 29^th of September 2019, using keywords related to 'senescence', 'age-related diseases' and 'biopsies'.

RESULTS

In total 12,590 articles were retrieved of which 103 articles were included in this review. The role of senescence in age-related disease has been assessed in 9 different human organ system and 27 different age-related diseases of which heart (27/103) and the respiratory systems (18/103) are the most investigated. Overall, 27 different markers of senescence have been used to determine cellular senescence and the cell cycle regulator p16^ink4a is most often used (23/27 age-related pathologies).

CONCLUSION

This review demonstrates that a higher expression of senescence markers are observed within disease pathologies. However, not all markers to detect senescence have been assessed in all tissue types.

The carotid plaque as paradigmatic case of site-specific acceleration of aging process: The microRNAs and the inflammaging contribution

Atherosclerosis is considered a chronic inflammatory disease of arteries associated with the aging process. Many risk factors have been identified and they are mainly related to life-styles, gene-environment interactions and socioeconomic status. Carotid and coronary artery diseases are the two major atherosclerotic conditions, being the primary cause of stroke and heart attack, respectively. Nevertheless, carotid plaque assumes particular aspects not only for the specific molecular mechanisms, but also for the types of atheroma which may be associated with a better or a worst prognosis. The identification of circulating blood biomarkers able to distinguish carotid plaque types (stable or vulnerable) is a crucial step for the improvement of adequate therapeutic approaches avoiding or delaying endarterectomy in the oldest old individuals (> 80 years), a population predicted to growth in the next years. The review highlights the most recent knowledge on carotid plaque molecular mechanisms, focusing on microRNAs (miRs), as a site-specific accelerated aging within the conceptual framework of Geroscience for new affordable therapies.

A role for autophagy in carotid atherosclerosis

Purpose

Autophagy has emerged in recent years as a critical cellular survival mechanism for cell homeostasis and may play a protective role in atherosclerosis. We aimed to review here the role autophagy plays in different cell types present in carotid atherosclerotic plaques and that may be associated with the development of unstable carotid atheroma plaque.

Methods

We performed a thorough literature exploration in this area of research covering the three main cell types present in carotid atheroma plaques.

Findings

Reviewed reports indicate that the role of autophagy in stable or unstable carotid atherosclerotic plaques depends on the different cell types and phenotypes, the stage and morphology of the plaque and the specific autophagy factor/s involved.

Discussion

Although defective autophagy could be one of the causes for carotid atheroma plaques to become unstable, it is important to take into account that autophagic players can act differentially in different cell types and different stages of the developed plaque.

Conclusion

This review provides an overview of the role of autophagy in the main cell types in carotid atherosclerosis (i.e. macrophages, endothelial cells and smooth muscle cells).

miR-125b targets DNMT3b and mediates p53 DNA methylation involving in the vascular smooth muscle cells proliferation induced by homocysteine

MicroRNAs (miRNAs) are short non-coding RNA and play crucial roles in a wide array of biological processes, including cell proliferation, differentiation and apoptosis. Our previous studies found that homocysteine(Hcy) can stimulate the proliferation of vascular smooth muscle cells (VSMCs), however, the underlying mechanisms were not fully elucidated. Here, we found proliferation of VSMCs induced by Hcy was of correspondence to the miR-125b expression reduced both in vitro and in the ApoE knockout mice, the hypermethylation of p53, its decreased expression, and DNA (cytosine-5)-methyltransferase 3b (DNMT3b) up-regulated. And, we found DNMT3b is a target of miR-125b, which was verified by the Dual-Luciferase reporter assay and western blotting. Besides, the siRNA interference for DNMT3b significantly decreased the methylation level of p53, which unveiled the causative role of DNMT3b in p53 hypermethylation. miR-125b transfection further confirmed its regulative roles on p53 gene methylation status and the VSMCs proliferation. Our data suggested that a miR-125b-DNMT3b-p53 signal pathway may exist in the VSMCs proliferation induced by Hcy.

High levels of cathepsin D and cystatin B are associated with increased risk of coronary events

Objective

The majority of acute coronary syndromes are caused by plaque ruptures. Proteases secreted by macrophages play an important role in plaque ruptures by degrading extracellular matrix proteins in the fibrous cap. Matrix metalloproteinases have been shown to be markers for cardiovascular disease whereas the members of the cathepsin protease family are less studied.

Methods

Cathepsin D, cathepsin L and cystatin B were measured in plasma at baseline from 384 individuals who developed coronary events (CEs), and from 409 age-matched and sex-matched controls from the Malmö Diet and Cancer cardiovascular cohort.

Results

Cathepsin D (180 (142–238) vs 163 (128–210), p<0.001), cathepsin L (55 (44–73) vs 52 (43–67), p<0.05) and cystatin B levels (45 (36–57) vs 42 (33–52), p<0.001) were significantly increased in CE cases compared to controls. In addition, increased cathepsin D (220 (165–313) vs 167 (133–211), p<0.001), cathepsin L (61 (46–80) vs 53 (43–68), p<0.05) and cystatin B (46 (38–58) vs 43 (34–54), p<0.05) were associated with prevalent diabetes. Furthermore, cathepsin D and cystatin B were increased in smokers. The HRs for incident CE comparing the highest to the lowest tertile(s) of cathepsin D and cystatin B were 1.34 (95% CI 1.02 to 1.75) and 1.26 (95% CI 1.01 to 1.57), respectively, after adjusting for age, sex, low-density lipoprotein/high-density lipoprotein ratio, triglycerides, body mass index, hypertension and glucose, but these associations did not remain significant after further addition of smoking to the model. In addition, cathepsin D was increased in incident CE cases among smokers after adjusting for cardiovascular risk factors.

Conclusions

The associations of cathepsin D and cystatin B with future CE provide clinical support for a role of these factors in cardiovascular disease, which for cathepsin D may be of particular importance for smokers.

The role of oxysterols in vascular ageing

The ageing endothelium progressively loses its remarkable and crucial ability to maintain homeostasis of the vasculature, as it acquires a proinflammatory phenotype. Cellular and structural changes gradually accumulate in the blood vessels, and markedly in artery walls. Most changes in aged arteries are comparable to those occurring during the atherogenic process, the latter being more marked: pro-oxidant and proinflammatory molecules, mainly deriving from or triggered by oxidized low density lipoproteins (oxLDLs), are undoubtedly a major driving force of this process. Oxysterols, quantitatively relevant components of oxLDLs, are likely candidate molecules in the pathogenesis of vascular ageing, because of their marked pro-oxidant, proinflammatory and proapoptotic properties. An increasing bulk of experimental data point to the contribution of a variety of oxysterols of pathophysiological interest, also in the age-related genesis of endothelium dysfunction, intimal thickening due to lipid accumulation, and smooth muscle cell migration and arterial stiffness due to increasing collagen deposition and calcification. This review provides an updated analysis of the molecular mechanisms whereby oxysterols accumulating in the wall of ageing blood vessels may 'activate' endothelial and monocytic cells, through expression of an inflammatory phenotype, and 'convince' smooth muscle cells to proliferate, migrate and, above all, to act as fibroblast-like cells.

Expression of NF-κB, CD68 and CD105 in carotid atherosclerotic plaque

Atherosclerotic plaque vulnerability is associated with cerebrovascular events in patients with carotid atherosclerosis. The aim of this study was to investigate the expression of inflammatory factors in carotid artherosclerotic plaques in order to explore its clinical significance in patients with carotid stenosis. Forty three patients with carotid stenosis were divided into symptomatic group (n=24) and asymptomatic group (n=19) based on clinical manifestation. All patients were treated with selective standard carotid endarterectomy (CEA); the carotid atherosclerotic plaques were removed surgically and studied pathologically to investigate the expression of nuclear factor-kappa κ (NF-κB), CD68 and CD105. The plaques were grouped into stable and unstable plaques based on thickness of the fibrous cap and the area of lipid-rich core in the plaques. The proportion of unstable plaques were significantly higher in symptomatic group than in asymptomatic group (70.8% vs. 63.2%, P=0.026). Results of immunohistochemisty staining showed that the expression of NF-κB, CD68 and CD105 in unstable plaques was higher than stable plaques (P<0.001). The association of the higher expression of these factors with instability of carotid plaque needs to be clarified in future study.

Oxysterols and symptomatic versus asymptomatic human atherosclerotic plaque

Atherosclerosis is the most common cause of mortality in the Western world, contributing to about 50% of all deaths. Atherosclerosis is characterized by deposition of lipids onto the coronary or carotid arterial wall and formation of an atherosclerotic plaque. Atherosclerotic plaques are categorized into two groups: symptomatic and asymptomatic. The symptomatic plaques tend to be unstable and prone to rupture, and are associated with an increase in ischemic events. Oxysterols, products of cholesterol oxidation, are cytotoxic materials. Their level and type may be associated with plaque formation, development and stability. Oxysterols stimulate the formation of foam cells, advance atherosclerotic plaque progression, and contribute to plaque vulnerability and instability due to their cytotoxicity and their ability to induce cell apoptosis. Studies indicate that plasma 7β-OH CH level can be used as a biomarker for detecting carotid and coronary artery disease. Further clinical studies are needed to evaluate the potential of oxysterols for use as biomarkers for plaque vulnerability and instability. The identification of biomarkers in the blood that can distinguish between symptomatic and asymptomatic plaques remains an unresolved issue.

Expression of NF-κB, CD68 and CD105 in carotid atherosclerotic plaque

Atherosclerotic plaque vulnerability is associated with cerebrovascular events in patients with carotid atherosclerosis. The aim of this study was to investigate the expression of inflammatory factors in carotid artherosclerotic plaques in order to explore its clinical significance in patients with carotid stenosis. Forty three patients with carotid stenosis were divided into symptomatic group (n=24) and asymptomatic group (n=19) based on clinical manifestation. All patients were treated with selective standard carotid endarterectomy (CEA); the carotid atherosclerotic plaques were removed surgically and studied pathologically to investigate the expression of nuclear factor-kappa κ (NF-κB), CD68 and CD105. The plaques were grouped into stable and unstable plaques based on thickness of the fibrous cap and the area of lipid-rich core in the plaques. The proportion of unstable plaques were significantly higher in symptomatic group than in asymptomatic group (70.8% vs. 63.2%, P=0.026). Results of immunohistochemisty staining showed that the expression of NF-κB, CD68 and CD105 in unstable plaques was higher than stable plaques (P<0.001). The association of the higher expression of these factors with instability of carotid plaque needs to be clarified in future study.

Redox signaling in cardiovascular health and disease

Spatiotemporal regulation of the activity of a vast array of intracellular proteins and signaling pathways by reactive oxygen species (ROS) governs normal cardiovascular function. However, data from experimental and animal studies strongly support that dysregulated redox signaling, resulting from hyperactivation of various cellular oxidases or mitochondrial dysfunction, is integral to the pathogenesis and progression of cardiovascular disease (CVD). In this review, we address how redox signaling modulates the protein function, the various sources of increased oxidative stress in CVD, and the labyrinth of redox-sensitive molecular mechanisms involved in the development of atherosclerosis, hypertension, cardiac hypertrophy and heart failure, and ischemia-reperfusion injury. Advances in redox biology and pharmacology for inhibiting ROS production in specific cell types and subcellular organelles combined with the development of nanotechnology-based new in vivo imaging systems and targeted drug delivery mechanisms may enable fine-tuning of redox signaling for the treatment and prevention of CVD.

A Systems Biology Approach to Characterize Biomarkers for Blood Stasis Syndrome of Unstable Angina Patients by Integrating MicroRNA and Messenger RNA Expression Profiling

Blood stasis syndrome (BSS) has been considered to be the major type of syndromes in unstable angina (UA) patients. The aim of this study was to find the systems biology-based microRNA (miRNA) and mRNA expression biomarkers for BSS of UA. We identified 1081 mRNAs and 25 miRNAs differentially expressed between BSS of UA patients and healthy controls by microarrays. We used DAVID, miRTrail, and the protein-protein interactions method to explore the related pathways and networks of differentially expressed miRNAs and mRNAs. By combining the results of pathways and networks, we found that the upregulation of miR-146b-5p may induce the downregulation of CALR to attenuate inflammation and the upregulation of miR-199a-5p may induce the downregulation of TP53 to inhibit apoptosis in BSS of UA patients. The expression patterns of miR-146b-5p, miR-199a-5p, CALR, and TP53 were confirmed by qRT-PCR in an independent validation cohort including BBS of UA patients, non-BBS of UA patients, and healthy controls. miR-146b-5p, miR-199a-5p, CALR, and TP53 could be significant biomarkers of BSS of UA patients. The systems biology-based miRNA and mRNA expression biomarkers for the BSS of UA may be helpful for the further stratification of UA patients when deciding on interventions or clinical trials.

Cell death induced by 7-oxysterols via lysosomal and mitochondrial pathways is p53-dependent

Oxysterol accumulation and p53 expression mainly in macrophages have been associated with cell death and necrotic core formation in human atheroma progression. Oxidative stress and lysosomal membrane permeabilization (LMP) in macrophages are important causes of macrophage apoptosis. However, it is not understood how p53 and oxysterols interact in the process. We show here that 7-oxysterols induce endogenous full-length p53 and phospho-p53 (p53-Ser15) in both nucleus and cytoplasm of THP1 and J774 cells, which is followed by cellular oxidative stress and apoptotic cell death. The role of p53 in 7-oxysterol-mediated cell death is further investigated in temperature sensitive p53-transfected (M1-t-p53) and in p53-deficient (M1) cells. These results reveal that 7-oxysterols induce induction and nuclear translocation of p53 in M1-t-p53 cells, which in turn enhances LMP, mitochondrial translocation of Bax, mitochondrial membrane permeabilization, cytosolic release of cytochrome c, and cell death. Most importantly, the above effects of 7-oxysterols were not observed in p53-deficient M1 cells. The findings reveal that 7-oxysterol-induced cell death occurs via p53-dependent pathways. Subsequent p53 nuclear translocation and induction of wild-type and phosphorylated p53 are early steps in oxysterol-induced lysosomal-mitochondrial pathways involved in cell death.

Up-regulated ATP-sensitive potassium channels play a role in increased inflammation and plaque vulnerability in macrophages

OBJECTIVE

Ion channels expressed in monocytes/macrophages have been tightly attached to atherosclerosis by coupling cellular function with electrical activity. However, the function of ATP-sensitive potassium channels (K(ATP)) in atherosclerosis has not been investigated directly. This study was performed to explore its role in atherosclerosis.

METHODS AND RESULTS

ApoE(-/-) mice with collar placement and Ad5-CMV.p53 or lac Z gene transfer with or without intragastric administration glibenclamide were applied to establish the progressive atherosclerosis at different time points and detect the function of K(ATP) channel in atherosclerosis. The expression and distribution of K(ATP) subunits in plaques were examined and a correlation between K(ATP) subunits expressed in macrophages, mainly Kir6.2 and SUR2A, and the vulnerability index of plaques was observed. In vitro, glibenclamide and pinacidil were used to detect the function and mechanism of K(ATP) channels in RAW264.7 cells stimulated by LPS. And the data showed that glibenclamide could ameliorate the progress of atherosclerosis and reduce the production of inflammatory cytokines as well as the phosphorylation of p65 and ERK1/2, while inhibitors of p65 leaded to robust expression of K(ATP) subunits in macrophages.

CONCLUSIONS

We concluded that K(ATP) channels in monocytes/macrophages were up-regulated and correlated with increased inflammation in vulnerable plaques, while glibenclamide could rescue the progression. K(ATP) channels may stimulate inflammatory reaction by MAPKs/NF-κB pathways in macrophages.

Humanin, a cytoprotective peptide, is expressed in carotid atherosclerotic [corrected] plaques in humans

OBJECTIVE

The mechanism of atherosclerotic plaque progression leading to instability, rupture, and ischemic manifestation involves oxidative stress and apoptosis. Humanin (HN) is a newly emerging endogenously expressed cytoprotective peptide. Our goal was to determine the presence and localization of HN in carotid atherosclerotic plaques.

METHODS AND RESULTS

Plaque specimens from 34 patients undergoing carotid endarterectomy were classified according to symptomatic history. Immunostaining combined with digital microscopy revealed greater expression of HN in the unstable plaques of symptomatic compared to asymptomatic patients (29.42±2.05 vs. 14.14±2.13% of plaque area, p<0.0001). These data were further confirmed by immunoblot (density of HN/β-actin standard symptomatic vs. asymptomatic 1.32±0.14 vs. 0.79±0.11, p<0.01). TUNEL staining revealed a higher proportion of apoptotic nuclei in the plaques of symptomatic patients compared to asymptomatic (68.25±3.61 vs. 33.46±4.46% of nuclei, p<0.01). Double immunofluorescence labeling revealed co-localization of HN with macrophages (both M1 and M2 polarization), smooth muscle cells, fibroblasts, and dendritic cells as well as with inflammatory markers MMP2 and MMP9.

CONCLUSIONS

The study demonstrates a higher expression of HN in unstable carotid plaques that is localized to multiple cell types within the plaque. These data support the involvement of HN in atherosclerosis, possibly as an endogenous response to the inflammatory and apoptotic processes within the atheromatous plaque.

NAMPT (visfatin) and AKT1 genetic variants associate with myocardial infarction

BACKGROUND

High plasma levels of the adipokine NAMPT (or visfatin) have been associated with cardiovascular disease. However experimental data suggest that NAMPT, via Akt signaling, protects the myocardium against hypoxic insults. We studied whether the NAMPT rs1319501, AKT1 rs3730358, p53 rs1042522, Mdm2 rs2279744 or eNOS rs1799983 SNP:s linked to NAMPT and Akt signaling associate with risk of myocardial infarction (MI).

METHODS

Cases were 828 men and 346 women aged 45-70 who had suffered a first MI. Control individuals, 1062 men and 513 women, were randomly chosen from the study base. We employed unconditional logistic regression analysis.

RESULTS

The rs1319501 minor allele associated with MI among women aged 45-60; odds ratio (OR) under a recessive model of inheritance: 2.96 (95% confidence interval [CI] 1.06-8.29). Replication analysis in an independent material yielded OR point estimates in the same direction. The rs3730358 minor allele associated with low MI risk in men aged 45-60 (OR dominant model: 0.72, 95% CI 0.53-0.97), an association completely attenuated by adjusting for inflammatory markers.

CONCLUSIONS

The NAMPT rs1319501 minor allele associates with increased MI risk in young women. In young men a protective effect of the AKT1 rs3730358 minor allele was suggested, possibly related to an attenuated inflammation.