Alpha-tocopherol and BAY 11-7082 reduce vascular cell adhesion molecule in human aortic endothelial cells

Role of inflammasomes in endothelial dysfunction

The vascular endothelium dynamically responds to environmental cues and plays a pivotal role in maintaining vascular homeostasis by regulating vasomotor tone, blood cell trafficking, permeability and immune responses. However, endothelial dysfunction results in various pathological conditions. Inflammasomes are large intracellular multimeric complexes activated by pathogens or cellular damage. Inflammasomes in vascular endothelial cells (ECs) initiate innate immune responses, which have emerged as significant mediators in endothelial dysfunction, contributing to the pathophysiology of an array of diseases. This review summarizes the mechanisms and ramifications of inflammasomes in ECs and related vascular diseases such as atherosclerosis, abdominal aortic aneurysm, stroke, and lung and kidney diseases. We also discuss potential drugs targeting EC inflammasomes and their applications in treating vascular diseases.

Vitamin E Supplementation and Cardiovascular Health: A Comprehensive Review

This article conducts a thorough investigation into the potential role of vitamin E in preventing cardiovascular diseases (CVDs) in the context of shifting mortality patterns from infectious diseases to the continued prominence of CVDs in modern medicine. The primary focus is on vitamin E's antioxidant properties and its specific ability to counter lipid peroxidation, a pivotal process in the early stages of atherosclerosis, a precursor to CVDs. The research spans a wide range of methodologies, including in vitro, in vivo, clinical, and experimental studies, examining how vitamin E affects critical aspects of cardiovascular health, such as signaling pathways, gene expression, inflammation, and cholesterol metabolism. It also explores vitamin E's influence on complex processes like smooth muscle cell development, oxidative stress reduction, foam cell formation, and the stability of atherosclerotic plaques. In the context of clinical studies, the article presents findings that both support and yield inconclusive results regarding the impact of vitamin E supplementation on CVDs. It acknowledges the intricate interplay of factors such as patient selection, pathophysiological conditions, and genetic variations, all of which can significantly influence the efficacy of vitamin E. The article underscores the need for ongoing research, with a specific focus on understanding the regulatory metabolites of vitamin E and their roles in modulating cellular processes relevant to CVDs. It highlights the potential for innovative therapeutic approaches based on a deeper comprehension of vitamin E's multifaceted effects. However, it also candidly addresses the challenges of translating clinical trial findings into practical applications and emphasizes the importance of considering diverse variables to optimize therapeutic outcomes. In summary, this meticulously conducted study provides a comprehensive examination of vitamin E's potential as a preventive agent against CVDs, recognizing the complexity of the subject and the need for continued research to unlock its full potential in cardiovascular health.

Spotlight on NLRP3 Inflammasome: Role in Pathogenesis and Therapies of Atherosclerosis

Inflammation is an intricate biological response of body tissues to detrimental stimuli. Cardiovascular disease (CVD) is the leading cause of death worldwide, and inflammation is well documented to play a role in the development of CVD, especially atherosclerosis (AS). Emerging evidence suggests that activation of the NOD-like receptor (NLR) family and the pyridine-containing domain 3 (NLRP3) inflammasome is instrumental in inflammation and may result in AS. The NLRP3 inflammasome acts as a molecular platform that triggers the activation of caspase-1 and the cleavage of pro-interleukin (IL)-1β, pro-IL-18, and gasdermin D (GSDMD). The cleaved GSDMD forms pores in the cell membrane and initiates pyroptosis, inducing cell death and the discharge of intracellular pro-inflammatory factors. Hence, the NLRP3 inflammasome is a promising target for anti-inflammatory therapy against AS. In this review, we systematically summarized the current understanding of the activation mechanism of NLRP3 inflammasome, and the pathological changes in AS involving NLRP3. We also discussed potential therapeutic strategies targeting NLRP3 inflammasome to combat AS.

Protective Role of Natural and Semi-Synthetic Tocopherols on TNFα-Induced ROS Production and ICAM-1 and Cl-2 Expression in HT29 Intestinal Epithelial Cells

Vitamin E, a fat-soluble compound, possesses both antioxidant and non-antioxidant properties. In this study we evaluated, in intestinal HT29 cells, the role of natural tocopherols, α-Toc and δ-Toc, and two semi-synthetic derivatives, namely bis-δ-Toc sulfide (δ-Toc)₂S and bis-δ-Toc disulfide (δ-Toc)₂S₂, on TNFα-induced oxidative stress, and intercellular adhesion molecule-1 (ICAM-1) and claudin-2 (Cl-2) expression. The role of tocopherols was compared to that of N-acetylcysteine (NAC), an antioxidant precursor of glutathione synthesis. The results show that all tocopherol containing derivatives used, prevented TNFα-induced oxidative stress and the increase of ICAM-1 and Cl-2 expression, and that (δ-Toc)₂S and (δ-Toc)₂S₂ are more effective than δ-Toc and α-Toc. The beneficial effects demonstrated were due to tocopherol antioxidant properties, but suppression of TNFα-induced Cl-2 expression seems not only to be related with antioxidant ability. Indeed, while ICAM-1 expression is strongly related to the intracellular redox state, Cl-2 expression is TNFα-up-regulated by both redox and non-redox dependent mechanisms. Since ICAM-1 and Cl-2 increase intestinal bowel diseases, and cause excessive recruitment of immune cells and alteration of the intestinal barrier, natural and, above all, semi-synthetic tocopherols may have a potential role as a therapeutic support against intestinal chronic inflammation, in which TNFα represents an important proinflammatory mediator.

Vitamin E: Regulatory role in the cardiovascular system

Cardiovascular disease (CVD) is one of the major causes of morbidity and mortality, all around the world. Vitamin E is an important nutrient influencing key cellular and molecular mechanisms as well as gene expression regulation centrally involved in the prevention of CVD. Cell culture and animal studies have focused on the identification of vitamin E regulated signaling pathways and involvement on inflammation, lipid homeostasis, and atherosclerotic plaque stability. While some of these vitamin E functions were verified in clinical trials, some of the positive effects were not translated into beneficial outcomes in epidemiological studies. In recent years, the physiological metabolites of vitamin E, including the liver derived (long- and short-chain) metabolites and phosphorylated (α-, γ-tocopheryl phosphate) forms, have also provided novel mechanistic insight into CVD regulation that expands beyond the vitamin E precursor. It is certain that this emerging insight into the molecular and cellular action of vitamin E will help to design further studies, either in animal models or clinical trials, on the reduction of risk for CVDs. This review focuses on vitamin E-mediated preventive cardiovascular effects and discusses novel insights into the biology and mechanism of action of vitamin E metabolites in CVD. © 2019 IUBMB Life, 71(4):507-515, 2019.

Current Therapies Focused on High-Density Lipoproteins Associated with Cardiovascular Disease

High-density lipoproteins (HDL) comprise a heterogeneous family of lipoprotein particles divided into subclasses that are determined by density, size and surface charge as well as protein composition. Epidemiological studies have suggested an inverse correlation between High-density lipoprotein-cholesterol (HDL-C) levels and the risk of cardiovascular diseases and atherosclerosis. HDLs promote reverse cholesterol transport (RCT) and have several atheroprotective functions such as anti-inflammation, anti-thrombosis, and anti-oxidation. HDLs are considered to be atheroprotective because they are associated in serum with paraoxonases (PONs) which protect HDL from oxidation. Polyphenol consumption reduces the risk of chronic diseases in humans. Polyphenols increase the binding of HDL to PON1, increasing the catalytic activity of PON1. This review summarizes the evidence currently available regarding pharmacological and alternative treatments aimed at improving the functionality of HDL-C. Information on the effectiveness of the treatments has contributed to the understanding of the molecular mechanisms that regulate plasma levels of HDL-C, thereby promoting the development of more effective treatment of cardiovascular diseases. For that purpose, Scopus and Medline databases were searched to identify the publications investigating the impact of current therapies focused on high-density lipoproteins.

Collagen and fibronectin surface modification of nanoporous anodic alumina and macroporous silicon for endothelial cell cultures

BACKGROUND

The ability to direct the cellular response by means of biomaterial surface topography is important for biomedical applications. Substrate surface topography has been shown to be an effective cue for the regulation of cellular response. Here, the response of human aortic endothelial cells to nanoporous anodic alumina and macroporous silicon with collagen and fibronectin functionalization has been studied.

METHODS

Confocal microscopy and scanning electron microscopy were employed to analyse the effects of the material and the porosity on the adhesion, morphology, and proliferation of the cells. Cell spreading and filopodia formation on macro- and nanoporous material was characterized by atomic force microscopy. We have also studied the influence of the protein on the adhesion.

RESULTS

It was obtained the best results when the material is functionalized with fibronectin, regarding cells adhesion, morphology, and proliferation.

CONCLUSION

These results permit to obtain chemical modified 3D structures for several biotechnology applications such as tissue engineering, organ-on-chip or regenerative medicine.

Silicon microgrooves for contact guidance of human aortic endothelial cells

Background: Micro- and nanoscale substrates have been fabricated in order to study the influence of the topography on the cellular response. The aim of this work was to prepare different collagen-coated silicon substrates displaying grooves and ridges to mimic the aligned and elongated endothelium found in linear vessels, and to use them as substrates to study cell growth and behaviour. Results: The influence of groove-shaped substrates on cell adhesion, morphology and proliferation were assessed, by comparing them to flat silicon substrates, used as control condition. Using human aortic endothelial cells, microscopy images demonstrate that the cellular response is different depending on the silicon surface, when it comes to cell adhesion, morphology (alignment, circularity and filopodia presence) and proliferation. Moreover, these structures exerted no cytotoxic effect. Conclusion: The results suggest that topographical patterning influences cell response. Silicon groove substrates can be used in developing medical devices with microscale features to mimic the endothelium in lineal vessels.

NSAIDs diclofenac, indomethacin, and meloxicam highly upregulate expression of ICAM-1 and COX-2 induced by X-irradiation in human endothelial cells

BACKGROUND

It is well known that radiation exposure to the heart and the use of non-steroidal anti-inflammatory drugs (NSAIDs) increase the risk of myocardial infarction (MI). Some NSAIDs are also known to act synergistically with ionizing radiation and have radio-sensitizing effects in radiotherapy. These evidences suggest that NSAIDs may affect the risk of MI after radiation exposure to the heart. In the present study, we investigated effects of NSAIDs on radiation-induced expression of cell adhesion molecules and COX-2, which are associated with inflammation and an increased risk of MI, in human endothelial cells.

METHODS

Effects of NSAIDs on radiation-induced expression of ICAM-1, VCAM-1, E-selectin, and COX-2 were investigated in human umbilical vein endothelial cells (HUVECs). As NSAIDs, diclofenac, etodolac, indomethacin, ketoprofen, meloxicam, and rofecoxib were used.

RESULTS

Irradiation with 10 Gy increased expression of ICAM-1 and COX-2, but it did not affect expression of VCAM-1 or E-selectin. All the NSAIDs upregulated radiation-induced expression of ICAM-1 and COX-2. The extent of upregulation varied depending on the types of NSAIDs. Indomethacin, diclofenac, and meloxicam highly upregulated radiation-induced expression of ICAM-1 and COX-2. The extent of upregulation was not related to the degree of COX-2 selectivity. An NF-κB inhibitor BAY 11-7082 suppressed radiation-induced expression of ICAM-1, but it did not suppress upregulated expression of ICAM-1 or COX-2 by combination treatment with X-irradiation and meloxicam, suggesting the existence of NF-κB-independent pathways for ICAM-1 and COX-2 induction.

CONCLUSION

Indomethacin, diclofenac, and meloxicam highly upregulated radiation-induced expression of ICAM-1 and COX-2 in HUVECs, which suggests that use of these NSAIDs may increase the effects of ionizing radiation and affect the risk of MI after radiation exposure to the heart.

Effects of SiO2 micropillar arrays on endothelial cells' morphology

Native tissues are highly organised at the microscale, so that modulating scaffold microarchitecture is a potent tool to mimic natural tissue structures. Moreover, three-dimensional microtopographical features are now being used to elucidate how extracellular physical cues can directly modulate cell behaviour and organise complex cellular processes such as cell differentiation and tissue organisation. Recent advances in microtechnology have allowed the development of platforms that can be used to further understand and control the complex interactions occurring between biointerfaces and living cells. In this paper, we discuss the use of three-dimensional microstructured substrates such as silicon dioxide micropillars, to interface with living cells. Human aortic endothelial cells were used to assess the biocompatibility of these substrates. Methodological investigations were performed to determine the influence of substrate topography on cell adhesion and growth. The changes on cell spreading and cell morphology induced by the substrates were qualified and quantified using scanning electron and fluorescence confocal microscopy.

Significant Modules and Biological Processes between Active Components of Salvia miltiorrhiza Depside Salt and Aspirin

The aim of this study is to examine and compare the similarities and differences between active components of S. miltiorrhiza depside salt and aspirin using perspective of pharmacological molecular networks. Active components of S. miltiorrhiza depside salt and aspirin's related genes were identified via the STITCH4.0 and GeneCards Database. A text search engine (Agilent Literature Search 2.71) and MCODE software were applied to construct network and divide modules, respectively. Finally, 32, 2, and 28 overlapping genes, modules, and pathways were identified between active components of S. miltiorrhiza depside salt and aspirin. A multidimensional framework of drug network showed that two networks reflected commonly in human aortic endothelial cells and atherosclerosis process. Aspirin plays a more important role in metabolism, such as the well-known AA metabolism pathway and other lipid or carbohydrate metabolism pathways. S. miltiorrhiza depside salt still plays a regulatory role in type II diabetes mellitus, insulin resistance, and adipocytokine signaling pathway. Therefore, this study suggests that aspirin combined with S. miltiorrhiza depside salt may be more efficient in treatment of CHD patients, especially those with diabetes mellitus or hyperlipidemia. Further clinical trials to confirm this hypothesis are still needed.

Common Phenolic Metabolites of Flavonoids, but Not Their Unmetabolized Precursors, Reduce the Secretion of Vascular Cellular Adhesion Molecules by Human Endothelial Cells

BACKGROUND

Flavonoids have been implicated in the prevention of cardiovascular disease; however, their mechanisms of action have yet to be elucidated, possibly because most previous in vitro studies have used supraphysiological concentrations of unmetabolized flavonoids, overlooking their more bioavailable phenolic metabolites.

OBJECTIVE

We aimed to explore the effects of phenolic metabolites and their precursor flavonoids at physiologically achievable concentrations, in isolation and combination, on soluble vascular cellular adhesion molecule-1 (sVCAM-1).

METHOD

Fourteen phenolic acid metabolites and 6 flavonoids were screened at 1 μM for their relative effects on sVCAM-1 secretion by human umbilical vein endothelial cells stimulated with tumor necrosis factor alpha (TNF-α). The active metabolites were further studied for their response at different concentrations (0.01 μM-100 μM), structure-activity relationships, and effect on vascular cellular adhesion molecule (VCAM)-1 mRNA expression. In addition, the additive activity of the metabolites and flavonoids was investigated by screening 25 unique mixtures at cumulative equimolar concentrations of 1 μM.

RESULTS

Of the 20 compounds screened at 1 μM, inhibition of sVCAM-1 secretion was elicited by 4 phenolic metabolites, of which protocatechuic acid (PCA) was the most active (-17.2%, P = 0.05). Investigations into their responses at different concentrations showed that PCA significantly reduced sVCAM-1 15.2-36.5% between 1 and 100 μM, protocatechuic acid-3-sulfate and isovanillic acid reduced sVCAM-1 levels 12.2-54.7% between 10 and 100 μM, and protocatechuic acid-4-sulfate and isovanillic acid-3-glucuronide reduced sVCAM-1 secretion 27.6% and 42.8%, respectively, only at 100 μM. PCA demonstrated the strongest protein response and was therefore explored for its effect on VCAM-1 mRNA, where 78.4% inhibition was observed only after treatment with 100 μM PCA. Mixtures of the metabolites showed no activity toward sVCAM-1, suggesting no additive activity at 1 μM.

CONCLUSIONS

The present findings suggest that metabolism of flavonoids increases their vascular efficacy, resulting in a diversity of structures of varying bioactivity in human endothelial cells.

Human aortic endothelial cell morphology influenced by topography of porous silicon substrates

Porous silicon has received much attention because of its optical properties and for its usefulness in cell-based biosensing, drug delivery, and tissue engineering applications. Surface properties of the biomaterial are associated with cell adhesion and with proliferation, migration, and differentiation. The present article analyzes the behavior of human aortic endothelial cells in macro- and nanoporous collagen-modified porous silicon samples. On both substrates, cells are well adhered and numerous. Confocal microscopy and scanning electron microscopy were employed to study the effects of porosity on the morphology of the cells. On macroporous silicon, filopodia is not observed but the cell spreads on the surface, increasing the lamellipodia surface which penetrates the macropore. On nanoporous silicon, multiple filopodia were found to branch out from the cell body. These results demonstrate that the pore size plays a key role in controlling the morphology and growth rate of human aortic endothelial cells, and that these forms of silicon can be used to control cell development in tissue engineering as well as in basic cell biology research.

Vitamin E: a potential therapy for gastric mucosal injury

CONTEXT

Many scientific reports have shown the involvement of oxidative stress and inflammation as well as diminished gastroprotective substances in the pathogenesis of gastric lesions using various models. Therefore, treatment with antioxidants like tocopherol and tocotrienol may afford beneficial effects in attentuating the formation of the gastric lesions.

OBJECTIVE

The aim of this work was to summarize documented reports on the effects of vitamin E on various models of gastric lesion.

METHODS

A literature search was performed from databases in Medline (PubMed), Web of Science, ScienceDirect, and Googlescholar from June to December 2013.

RESULTS AND CONCLUSION

The potential roles of tocopherol and tocotrienol in modifying the effects of ulcerogenic agents are discussed in this review. The protective effects of the vitamin E might involve ameliorating oxidative stress and inflammation as well as restoration of endogenous gastroprotective substances. This vitamin has the potential to be used as a therapy for gastric mucosal injury.

Regulatory metabolites of vitamin E and their putative relevance for atherogenesis

Vitamin E is likely the most important antioxidant in the human diet and α-tocopherol is the most active isomer. α-Tocopherol exhibits anti-oxidative capacity in vitro, and inhibits oxidation of LDL. Beside this, α-tocopherol shows anti-inflammatory activity and modulates expression of proteins involved in uptake, transport and degradation of tocopherols, as well as the uptake, storage and export of lipids such as cholesterol. Despite promising anti-atherogenic features in vitro, vitamin E failed to be atheroprotective in clinical trials in humans. Recent studies highlight the importance of long-chain metabolites of α-tocopherol, which are formed as catabolic intermediate products in the liver and occur in human plasma. These metabolites modulate inflammatory processes and macrophage foam cell formation via mechanisms different than that of their metabolic precursor α-tocopherol and at lower concentrations. Here we summarize the controversial role of vitamin E as a preventive agent against atherosclerosis and point the attention to recent findings that highlight a role of these long-chain metabolites of vitamin E as a proposed new class of regulatory metabolites. We speculate that the metabolites contribute to physiological as well as pathophysiological processes.

Endothelial G protein-coupled receptor kinase 2 regulates vascular homeostasis through the control of free radical oxygen species

OBJECTIVE

The role of endothelial G protein-coupled receptor kinase 2 (GRK2) was investigated in mice with selective deletion of the kinase in the endothelium (Tie2-CRE/GRK2(fl/fl)).

APPROACH AND RESULTS

Aortas from Tie2-CRE/GRK2(fl/fl) presented functional and structural alterations as compared with control GRK2(fl/fl) mice. In particular, vasoconstriction was blunted to different agonists, and collagen and elastic rearrangement and macrophage infiltration were observed. In primary cultured endothelial cells deficient for GRK2, mitochondrial reactive oxygen species was increased, leading to expression of cytokines. Chronic treatment with a reactive oxygen species scavenger in mice corrected the vascular phenotype by recovering vasoconstriction, structural abnormalities, and reducing macrophage infiltration.

CONCLUSIONS

These results demonstrate that GRK2 removal compromises vascular phenotype and integrity by increasing endothelial reactive oxygen species production.

Poly(ADP-ribose) polymerase 1 inhibition protects human aortic endothelial cells against LPS-induced inflammation response

Atherosclerosis is a chronic inflammatory disease. Toll-like receptor 4 (TLR4) is an important signaling receptor and plays a critical role in the inflammatory response. Poly(ADP-ribose) polymerase 1 (PARP1) is a nuclear enzyme that can regulate the expression of various inflammatory genes. In this study, we investigated the role and the underlying mechanisms of PARP1 on lipopolysaccharide (LPS)-induced inflammation in human aortic endothelial cells. Compared with the control, LPS stimulation increased the protein expression of TLR4 and PARP1. TLR4 inhibition reduced LPS-induced upregulation of inducible nitric oxide synthase (iNOS) and ICAM-1 as well as PARP1. Nuclear factor κB (NF-κB) inhibition decreased ICAM-1 and iNOS expression. Inhibition of PARP1 decreased protein expression of inflammatory cytokines induced by LPS stimulation, probably through preventing NF-κB nuclear translocation. Our study demonstrated that LPS increased ICAM-1 and iNOS expression via TLR4/PARP1/NF-κB pathway. PARP1 might be an indispensable factor in TLR4-mediated inflammation after LPS stimulation. PARP1 inhibition might shed light on the treatment of LPS-induced inflammatory cytokines expression during atherosclerosis.