The antagonist of P2Y11 receptor NF157 ameliorates oxidized LDL-induced vascular endothelial inflammation

Drug-like Antagonists of P2Y Receptor Subtypes: An Update

The hunt for drug-like P2YR antagonists continues, stimulated by ever-increasing pharmacological evidence for their clinical benefit and the astonishing array of biological functions which they orchestrate, including platelet aggregation, cancer proliferation, pain, neurodegenerative diseases, and immune regulation. Extensive research has identified modulators of P2Y receptors. However, only a limited number of small-molecule antagonists for the P2Y12 receptor have received approval for their clinical use. Recent pioneering discoveries of small-molecule ligand-bound X-ray crystal structures for the P2Y1 and P2Y12 receptors and homology modeling has stimulated research groups to explore orthosteric and allosteric receptor antagonists, aided in part by the discovery of fluorescent P2YR imaging tools and sensitive screening methods that allow the identification of low affinity P2Y receptor antagonists. This Perspective critically assesses P2Y receptor antagonists published since 2016, highlighting potential oral lead- or drug-like compounds that offer opportunities for the development of molecules for clinical evaluation.

Apelin-13 Inhibits the Adhesion of Monocytes to Endothelial Cells via the Gfi1/NF-κB Signaling Pathway

Oxidized low-density lipoprotein (ox-LDL)-induced endothelial dysregulation and the abnormal interaction between monocytes have been considered key risk factors for atherosclerosis. The study investigated the effects of apelin-13 on ox-LDL-induced endothelial dysfunction in human aortic endothelial cells (HAECs). Cells were stimulated with ox-LDL (100 mg/L), either alone or in combination with apelin-13 at concentrations of 3 and 6 µM. Multiple techniques, including real-time PCR, Western blot analysis, enzyme-linked immunosorbent assay (ELISA), cell attachment assays, and luciferase activity assays, were employed. Our results showed that ox-LDL reduced the expression of the G-protein-coupled apelin receptor (APJ) in HAECs. However, treatment with apelin-13 reduced the expression of lectin-like ox-LDL receptor 1 (LOX-1) against ox-LDL and inhibited the expression of pro-inflammatory cytokines in HAECs. Real-time PCR and ELISA assay demonstrated that apelin-13 also inhibited the expression of cell adhesion molecules intercellular cell adhesion molecule-1 (ICAM-1) and E-selectin. The calcein AM staining method displayed that apelin-13 mitigated ox-LDL-induced attachment of THP-1 monocytes to HAECs. Furthermore, apelin-13 prevented the reduction of growth factor independence-1 (Gfi1) and the activation of NF-κB in HAECs, as evidenced by the luciferase activity assay. Knockdown of Gfi1 counteracted the inhibitory effects of apelin-13 on the attachment of THP-1 monocytes to HAECs, suggesting that the protective effects of apelin-13 in endothelial dysfunction are mediated by the Gfi1/ NF-κB signaling pathway. These findings suggest that apelin-13 may have therapeutic potential in preventing atherosclerosis by improving endothelial function and reducing inflammation.

How selective antagonists and genetic modification have helped characterise the expression and functions of vascular P2Y receptors

Vascular P2Y receptors mediate many effects, but the role of individual subtypes is often unclear. Here we discuss how subtype-selective antagonists and receptor knockout/knockdown have helped identify these roles in numerous species and vessels. P2Y1 receptor-mediated vasoconstriction and endothelium-dependent vasodilation have been characterised using the selective antagonists, MRS2179 and MRS2216, whilst AR-C118925XX, a P2Y2 receptor antagonist, reduced endothelium-dependent relaxation, and signalling evoked by UTP or fluid shear stress. P2Y2 receptor knockdown reduced endothelial signalling and endothelial P2Y2 receptor knockout produced hypertensive mice and abolished vasodilation elicited by an increase in flow. UTP-evoked vasoconstriction was also blocked by AR-C118925XX, but the effects of P2Y2 receptor knockout were complex. No P2Y4 receptor antagonists are available and P2Y4 knockout did not affect the vascular actions of UTP and UDP. The P2Y6 receptor antagonist, MRS2578, identified endothelial P2Y6 receptors mediating vasodilation, but receptor knockout had complex effects. MRS2578 also inhibited, and P2Y6 knockout abolished, contractions evoked by UDP. P2Y6 receptors contribute to the myogenic tone induced by a stepped increase in vascular perfusion pressure and possibly to the development of atherosclerosis. The P2Y11 receptor antagonists, NF157 and NF340, inhibited ATP-evoked signalling in human endothelial cells. Vasoconstriction mediated by P2Y12/P2Y13 and P2Y14 receptors was characterised using the antagonists, cangrelor, ticagrelor, AR-C67085 and MRS2211 or PPTN respectively. This has yet to be backed up by receptor knockout experiments. Thus, subtype-selective antagonists and receptor knockout/knockdown have helped identify which P2Y subtypes are functionally expressed in vascular smooth muscle and endothelial cells and the effects that they mediate.

NADPH-oxidases as potential pharmacological targets for thrombosis and depression comorbidity

There is a complex interrelationship between the nervous system and the cardiovascular system. Comorbidities of cardiovascular diseases (CVD) with mental disorders, and vice versa, are prevalent. Adults with mental disorders such as anxiety and depression have a higher risk of developing CVD, and people with CVD have an increased risk of being diagnosed with mental disorders. Oxidative stress is one of the many pathways associated with the pathophysiology of brain and cardiovascular disease. Nicotinamide adenine dinucleotide phosphate oxidase (NOX) is one of the major generators of reactive oxygen species (ROS) in mammalian cells, as it is the enzyme that specifically produces superoxide. This review summarizes recent findings on the consequences of NOX activation in thrombosis and depression. It also discusses the therapeutic effects and pharmacological strategies of NOX inhibitors in CVD and brain disorders. A better comprehension of these processes could facilitate the development of new therapeutic approaches for the prevention and treatment of the comorbidity of thrombosis and depression.

Degranulation of human mast cells: modulation by P2 receptors' agonists

Since the late 1970s, there has been an alarming increase in the incidence of asthma and its morbidity and mortality. Acute obstruction and inflammation of allergic asthmatic airways are frequently caused by inhalation of exogenous substances such as allergens cross-linking IgE receptors expressed on the surface of the human lung mast cells (HLMC). The degree of constriction of human airways produced by identical amounts of inhaled allergens may vary from day to day and even hour to hour. Endogenous factors in the human mast cell (HMC)'s microenvironment during allergen exposure may markedly modulate the degranulation response. An increase in allergic responsiveness may significantly enhance bronchoconstriction and breathlessness. This review focuses on the role that the ubiquitous endogenous purine nucleotide, extracellular adenosine 5'-triphosphate (ATP), which is a component of the damage-associated molecular patterns, plays in mast cells' physiology. ATP activates P2 purinergic cell-surface receptors (P2R) to trigger signaling cascades resulting in heightened inflammatory responses. ATP is the most potent enhancer of IgE-mediated HLMC degranulation described to date. Current knowledge of ATP as it relates to targeted receptor(s) on HMC along with most recent studies exploring HMC post-receptor activation pathways are discussed. In addition, the reviewed studies may explain why brief, minimal exposures to allergens (e.g., dust, cat, mouse, and grass) can unpredictably lead to intense clinical reactions. Furthermore, potential therapeutic approaches targeting ATP-related enhancement of allergic reactions are presented.

Mettl3 promotes oxLDL-mediated inflammation through activating STAT1 signaling

Background

Atherosclerosis (AS) is the main cause of cerebrovascular diseases, and macrophages act important roles during the AS pathological process through regulating inflammation. Modification of the novel N(6)‐methyladenine (m6A) RNA is reported to be associated with AS, but its role in AS is largely unknown. The aim of this study was to investigate the role and mechanism of m6A modification in inflammation triggered by oxidized low‐density lipoprotein (oxLDL) in macrophages during AS.

Methods

RAW264.7 macrophage cells were stimulated with 40 μg/ml ox‐LDL, Dot blot, Immunoprecipitation, western blot, Rip and chip experiments were used in our study.

Results

We found oxLDL stimulation significantly promoted m6A modification level of mRNA in macrophages and knockdown of Methyltransferase‐Like Protein 3 (Mettl3) inhibited oxLDL‐induced m6A modification and inflammatory response. Mettl3 promoted oxLDL‐induced inflammatory response in macrophages through regulating m6A modification of Signal transducer and activator of transcription 1 (STAT1) mRNA, thereby affecting STAT1 expression and activation. Moreover, oxLDL stimulation enhanced the interaction between Mettl3 and STAT1 protein, promoting STAT1 transcriptional regulation of inflammatory factor expression in macrophages eventually.

Conclusions

These results indicate that Mettl3 promotes oxLDL‐triggered inflammation through interacting with STAT1 protein and mRNA in RAW264.7 macrophages, suggesting that Mettl3 may be as a potential target for the clinical treatment of AS.

Enhancement of Mast Cell Degranulation Mediated by Purinergic Receptors' Activation and PI3K Type δ

Mast cells express multiple metabotropic purinergic P2Y receptor (P2YR) subtypes. Few studies have evaluated their role in human mast cell (HMC) allergic response as quantified by degranulation induced by cross-linking the high-affinity IgE receptor (FcεRI). We have previously shown that extracellular nucleotides modify the FcεRI activation-dependent degranulation in HMCs derived from human lungs, but the mechanism of this action has not been fully delineated. This study was undertaken to determine the mechanism of activation of P2YRs on the degranulation of HMCs and elucidate the specific postreceptor pathways involved. Sensitized LAD2 cells, a human-derived mast cell line, were subjected to a weak allergic stimulation (WAS) using a low concentration of Ag in the absence and presence of P2YR agonists. Only the metabotropic purinergic P2Y11 receptor (P2Y11R) agonist, adenosine 5'-(3-thio)triphosphate (ATPγS), enhanced WAS-induced degranulation resulting in a net 7-fold increase in release (n = 4; p < 0.01). None of the P2YR agonists tested, including high concentrations of ATPγS (1000 μM), enhanced WAS-induced intracellular Ca²⁺ mobilization, an essential component of activated FcεRI-induced degranulation. Both a PI3K inhibitor and the relevant gene knockout decreased the ATPγS-induced enhancement. The effect of ATPγS was associated with enhanced phosphorylation of PI3K type δ and protein kinase B, but not the phosphoinositide-dependent kinase-1. The effects of ATPγS were dose dependently inhibited by NF157, a P2Y11R antagonist. To our knowledge, these data indicate for the first time that P2YR is linked to enhancement of allergic degranulation in HMC via the PI3K/protein kinase B pathway.

Expression of LncRNA DLGAP1-AS1 in a Mouse Model of Atherosclerosis and Its Effect on Oxidized Low-Density Lipoprotein-Induced Vascular Endothelial Cell Injury

The occurrence of vascular endothelial injury is key to the progression of atherosclerosis (AS). This research explores the expression of lncRNA DLGAP1-AS1 in a mouse model of atherosclerosis and its effect on ox-LDL-induced vascular endothelial cell injury. A mouse model of AS was constructed, and DLGAP1-AS1 expression was detected using the nano real-time PCR method. Vascular endothelial cells (VEC) are categorized into four groups. Flow cytometry detects cell apoptosis, and Western blot detects Bax and Bcl-2 expressions; WST-8 method detects level of SOD. Thiobarbituric acid method, Ammonium molybdate colorimetric method, DCFH-DA method were used to detect MDA, CAT, and reactive oxygen species (ROS) levels, respectively. Bioinformatics software predicted the target genes of DLGAP1-AS1. DLGAP1-AS1 expression was raised in AS mice, apoptotic rate and Bax expression in the ox-LDL group were raised, Bcl-2 expression was abated, MDA and ROS levels were raised, SOD and CAT levels were abated than in control. The si-DLGAP1-AS1+ox-LDL group decreased cell death and Bax expression, increased Bcl-2 expression, decreased MDA and ROS levels, and increased SOD and CAT levels than in the si-NC+ox-LDL group. Down-regulation of DLGAP1-AS1 was targeted in order to promote miR-26a-5p expression. Compared with co-transfection with DLGAP1-AS1 siRNA and inhibitor control, the apoptosis rate and Bax expression were increased after co-transfection with DLGAP1-AS1 siRNA and miR-26a-5p inhibitor, Bcl-2 expression was decreased, and MDA and ROS levels were increased, the level of SOD and CAT were decreased. DLGAP1-AS1 was up-regulated in AS mice and downregulated to promote miR-26a-5p to inhibit ox-LDL-induced vascular endothelial cell death and oxidative damage.

Modeling early stage atherosclerosis in a primary human vascular microphysiological system

Novel atherosclerosis models are needed to guide clinical therapy. Here, we report an in vitro model of early atherosclerosis by fabricating and perfusing multi-layer arteriole-scale human tissue-engineered blood vessels (TEBVs) by plastic compression. TEBVs maintain mechanical strength, vasoactivity, and nitric oxide (NO) production for at least 4 weeks. Perfusion of TEBVs at a physiological shear stress with enzyme-modified low-density-lipoprotein (eLDL) with or without TNFα promotes monocyte accumulation, reduces vasoactivity, alters NO production, which leads to endothelial cell activation, monocyte accumulation, foam cell formation and expression of pro-inflammatory cytokines. Removing eLDL leads to recovery of vasoactivity, but not loss of foam cells or recovery of permeability, while pretreatment with lovastatin or the P2Y11 inhibitor NF157 reduces monocyte accumulation and blocks foam cell formation. Perfusion with blood leads to increased monocyte adhesion. This atherosclerosis model can identify the role of drugs on specific vascular functions that cannot be assessed in vivo.

P2Y Purinergic Receptors, Endothelial Dysfunction, and Cardiovascular Diseases

Purinergic G-protein-coupled receptors are ancient and the most abundant group of G-protein-coupled receptors (GPCRs). The wide distribution of purinergic receptors in the cardiovascular system, together with the expression of multiple receptor subtypes in endothelial cells (ECs) and other vascular cells demonstrates the physiological importance of the purinergic signaling system in the regulation of the cardiovascular system. This review discusses the contribution of purinergic P2Y receptors to endothelial dysfunction (ED) in numerous cardiovascular diseases (CVDs). Endothelial dysfunction can be defined as a shift from a “calm” or non-activated state, characterized by low permeability, anti-thrombotic, and anti-inflammatory properties, to a “activated” state, characterized by vasoconstriction and increased permeability, pro-thrombotic, and pro-inflammatory properties. This state of ED is observed in many diseases, including atherosclerosis, diabetes, hypertension, metabolic syndrome, sepsis, and pulmonary hypertension. Herein, we review the recent advances in P2Y receptor physiology and emphasize some of their unique signaling features in pulmonary endothelial cells.

Therapeutic Potential of Polyphenols-Loaded Polymeric Nanoparticles in Cardiovascular System

Numerous studies document an increased production of reactive oxygen species (ROS) with a subsequent decrease in nitric oxide (NO) bioavailability in different cardiovascular diseases, including hypertension, atherosclerosis, and heart failure. Many natural polyphenols have been demonstrated to decrease ROS generation and/or to induce the endogenous antioxidant enzymatic defense system. Moreover, different polyphenolic compounds have the ability to increase the activity/expression of endothelial nitric oxide synthase (eNOS) with a subsequent enhancement of NO generation. However, as a result of low absorption and bioavailability of natural polyphenols, the beneficial effects of these substances are very limited. Recent progress in delivering polyphenols to the targeted tissues revealed new possibilities for the use of polymeric nanoparticles in increasing the efficiency and reducing the degradability of natural polyphenols. This review focuses on the effects of different natural polyphenolic substances, especially resveratrol, quercetin, curcumin, and cherry extracts, and their ability to bind to polymeric nanoparticles, and summarizes the effects of polyphenol-loaded nanoparticles, mainly in the cardiovascular system.