Platelets and their chemokines in atherosclerosis-clinical applications

The concept of platelets as important players in the process of atherogenesis has become increasingly accepted due to accumulating experimental and clinical evidence. Despite the progress in understanding the molecular details of atherosclerosis, particularly by using animal models, the inflammatory and thrombotic roles of activated platelet s especially in the human system remain difficult to dissect, as often only the complications of atherosclerosis, i.e., stroke and myocardial infarction are definable but not the plague burden. Platelet indices including platelet count and mean platelet volume (MPV) and soluble mediators released by activated platelets are associated with atherosclerosis. The chemokine CXCL4 has multiple atherogenic activities, e.g., altering the differentiation of T cells and macrophages by inhibiting neutrophil and monocyte apoptosis and by increasing the uptake of oxLDL and synergizing with CCL5. CCL5 is released and deposited on endothelium by activated platelets thereby triggering atherogenic monocyte recruitment, which can be attenuated by blocking the corresponding chemokine receptor CCR5. Atheroprotective and plague stabilizing properties are attributed to CXCL12, which plays an important role in regenerative processes by attracting progenitor cells. Its release from luminal attached platelets accelerates endothelial healing after injury. Platelet surface molecules GPIIb/IIIa, GP1b alpha, P-selectin, JAM-A and the CD40/CD40L dyade are crucially involved in the interaction with endothelial cells, leukocytes and matrix molecules affecting atherogenesis. Beyond the effects on the arterial inflammatory infiltrate, platelets affect cholesterol metabolism by binding, modifying and endocytosing LDL particles via their scavenger receptors and contribute to the formation of lipid laden macrophages. Current medical therapies for the prevention of atherosclerotic therapies enable the elucidation of mechanisms linking platelets to inflammation and atherosclerosis

Mechanisms of HIV-Nef Induced Endothelial Cell Stress: Implications of HIV-Nef Protein Persistence in Aviremic HIV Patients

Indiana University-Purdue University Indianapolis (IUPUI)HIV-associated cardio-pulmonary vascular pathologies such as coronary artery disease, pulmonary hypertension and emphysema remain a major issue in the HIVinfected population even in the era of antiretroviral therapy (ART). The continued production of HIV encoded pro-apoptotic protein, such as Nef in latently HIV-infected cells is a possible mechanism for vascular dysfunction underlying these diseases. HIVNef persists in two compartments in these patients: (i) extracellular vesicles (EV) of plasma and bronchoalveolar lavage (BAL) fluid and (ii) PBMC and BAL derived cells. Here I demonstrate that the presence of HIV-Nef protein in cells and EV is capable of stressing endothelial cells by inducing ROS production leading to endothelial cell apoptosis. HIV-Nef protein hijacks host cell signaling by interacting with small GTP binding protein Rac1 which activates PAK2 to promote the release of pro-apoptotic cargo containing EV and surface expression of pro-apoptotic protein Endothelial Monocyte Activating Polypeptide II (EMAPII). Using this mechanism, Nef protein robustly induces apoptosis in Human Coronary Artery Endothelial Cells and Human Lung microvascular endothelial cells. Endothelial specific expression of HIV-Nef protein in transgenic mice was sufficient to induce vascular pathologies as evidenced by impaired endothelium mediated vasodilation of the aorta and vascular remodeling and emphysema like alveolar rarefaction in the lung. Furthermore, EV isolated from HIV patients on ART was capable of inducing endothelial apoptosis in a Nef dependent fashion. Of therapeutic interest, EMAPII neutralizing antibodies to block EMAPII mediated apoptosis and statin treatment to ameliorate Nef induced Rac1 signaling was capable of blocking Nef induced endothelial stress in both in vivo and in vitro. In conclusion, HIV-Nef protein uses a Rac1-Pak2 signaling axis to promote its dissemination in EV, which in turn induces endothelial cell stress after its uptake

Cross-talk between lipoproteins and inflammation : The role of microvesicles

Atherothrombosis is the principal underlying cause of cardiovascular disease (CVD). Microvesicles (MV) are small blebs originated by an outward budding at the cell plasma membranes, which are released in normal conditions. However, MV release is increased in pathophysiologic conditions such as CVD. Low density lipoprotein (LDL) and MV contribute to atherothrombosis onset and progression by promoting inflammation and leukocyte recruitment to injured endothelium, as well as by increasing thrombosis and plaque vulnerability. Moreover, (oxidized)LDL induces MV release and vice-versa, perpetuating endothelium injury leading to CVD progression. Therefore, MV and lipoproteins exhibit common features, which should be considered in the interpretation of their respective roles in the pathophysiology of CVD. Understanding the pathways implicated in this process will aid in developing novel therapeutic approaches against atherothrombosis

The role and therapeutic potential of extracellular vesicles in atherosclerosis

Atherosclerosis, the pathophysiology of many cardiovascular diseases (CVD), is a chronic inflammatory process caused by the sustained accumulation of cholesterol, followed by endothelial dysfunction, and the resulting vascular inflammation. The established treatment for atherosclerosis, to date, involves the use of statins. These medications are hydroxymethylglutaryl coenzyme A reductase (HMG-CoA) inhibitors and lower the levels of by inhibiting HMG-CoA, a rate limiting step in the biosynthesis of cholesterol. Statin therapy varies in effectiveness based on dosage and individual differences, making effective treatment of patients challenging. More recently, extracellular vesicles (EVs) have emerged as a promising field in cardiovascular research. Once thought of as “platelet dust,” EVs are now recognized for their potential as therapeutic targets and tools. In this review, a comprehensive characterization of EVs is provided to explain how EVs are involved in normal physiological function and pathological processes of atherosclerosis. Evidence supports a model where EVs participate in the initiation and progression of atherosclerosis and may also be used as a delivery tool in disease therapy. Currently, cell-derived EVs can be therapeutic agents in animal models, an effective tool in gene therapy, or a drug delivery vehicle. Future experiments enhancing the therapeutic potential of EVs promise to deepen our understanding of EV-based therapy for atherosclerosis precision medicine

Characterization of the cargo of circulating extracellular vesicles in patients affected with idiopathic inflammatory myopathies and evaluation of clinical correlates in a cross-sectional comparative analysis from a monocentric cohort.

openBackground Idiopathic inflammatory myopathies (IIM) are heterogeneous autoimmune disorders that comprise different clinical entities, characterized by different features. Although several myositis-specific and myositis-associated antibodies have been characterized, the molecular mechanisms underlying these conditions require further exploration. The research field on extracellular vescicles (EVs) is rapidly evolving, highlighting their role in intercellular communication. EVs convoy a cargo of proteins and nucleic acids, such as microRNA (miRNAs), that mediate immune-response regulation in autoimmune diseases. miRNAs regulate gene-expression post-transcriptionally and are involved in multiple molecular pathways of human disease. Evidence of EVs and miRNAs in IIM is still limited and undefined. Aim of the study This study aims to quantify the circulating EVs and characterize their cargo, with a specific focus on miRNAs content to propose novel biomarkers of IIM. Materials and methods A monocentric study was conducted including adult IIM patients (≥18 years old) followed at the Rheumatology Unit of Padua University Hospital, and age- and sex- matched healthy controls (HD). EVs were isolated from platelet-free plasma through size exclusion chromatography followed by ultrafiltration. EVs were quantified by nanoparticle tracking analysis (NTA) and. EV-miRNA cargo was investigated through Next-Generation Sequencing (NGS). Statistical analysis was performed with parametric Student-T test and one-way Anova (Bonferroni correction). Results Sixty-four consecutive IIM patients and sixty-five HDs were included in the study. NTA measurements of EVs concentration showed a significantly higher mean concentration of circulating EVs in IIM patients than in HD (p=0.0073). Across IIM subsets, patients affected with cancer associated myositis (CAM) displayed the highest levels of circulating EVs compared to no CAM patients (p=0.0060) and to HD (p=0.0004). Patients with circulating myositis-associated autoantibodies displayed significantly higher EV levels than HD (p=0.0363). Patients in clinical remission displayed higher levels of circulating EVs compared to those with active disease (p=0.0087). EVs levels were significantly reduced in IIM patients treated with rituximab (RTX) than in patients receiving other treatments (p<0.0001). NGS analysis detected EV-miRNAs with different expression profiles between IIM (n=47) and HDs (n=49): miR-223-3p (p=0.019), miR-15a-5p (p=0.0189), miR-451a (p=0.0074), miR-486-5p (p=0.0052), miR-32-5p (p=0.0146), and miR-222-3p (p=0.0282) were up-regulated in IIM, while miR-141-3p (p=0.0313), miR-142-3p (p=0.0244), and let-7a-5p (p=0.0003) were down-regulated in IIM patients vs. HDs. Other EV-miRNAs expression varied across IIM subsets: CAM patients displayed up-regulated expression of miR-143-3p compared to non-CAM patients (p=0.0085), while miR-148a-3p (p=0.0171) and miR-335-5p (p=0.0171) were up-regulated in dermatomyositis vs. polymyositis/ inclusion body myositis/anti-synthetase syndrome patients. Patients characterized by active disease displayed an up-regulated expression of miR-222-3p (p=0.002) and miR-151-3p (p=0.0233) and down-regulated expression of miR-363-3p (p=0.0001), miR-374a-5p (p=0.0258), miR-144-3p (p=0.0170), miR-181a-5p (p=0.0037) compared to those in clinical remission. Moreover, IIM patients receiving only glucocorticoids (GC) reported up-regulated expression of miR-4433b-5p (p=0.0439), miR-92a-3p (p=0.0111), let-7f-5p (p=0.0304), and down-regulated expression of miR-27a-3p (p=0.0486) compared to patients receiving GC in combination with immunosuppressants (IS). Conclusions Our results showed significantly increased concentration of circulating EVs in IIM patients. That is confirmed within specific disease phenotypes and pharmacological treatments. EV miRNAs exhibited a differential expression profile between IIM and HD, and significant differences were outlined among IIM subsets.Background Idiopathic inflammatory myopathies (IIM) are heterogeneous autoimmune disorders that comprise different clinical entities, characterized by different features. Although several myositis-specific and myositis-associated antibodies have been characterized, the molecular mechanisms underlying these conditions require further exploration. The research field on extracellular vescicles (EVs) is rapidly evolving, highlighting their role in intercellular communication. EVs convoy a cargo of proteins and nucleic acids, such as microRNA (miRNAs), that mediate immune-response regulation in autoimmune diseases. miRNAs regulate gene-expression post-transcriptionally and are involved in multiple molecular pathways of human disease. Evidence of EVs and miRNAs in IIM is still limited and undefined. Aim of the study This study aims to quantify the circulating EVs and characterize their cargo, with a specific focus on miRNAs content to propose novel biomarkers of IIM. Materials and methods A monocentric study was conducted including adult IIM patients (≥18 years old) followed at the Rheumatology Unit of Padua University Hospital, and age- and sex- matched healthy controls (HD). EVs were isolated from platelet-free plasma through size exclusion chromatography followed by ultrafiltration. EVs were quantified by nanoparticle tracking analysis (NTA) and. EV-miRNA cargo was investigated through Next-Generation Sequencing (NGS). Statistical analysis was performed with parametric Student-T test and one-way Anova (Bonferroni correction). Results Sixty-four consecutive IIM patients and sixty-five HDs were included in the study. NTA measurements of EVs concentration showed a significantly higher mean concentration of circulating EVs in IIM patients than in HD (p=0.0073). Across IIM subsets, patients affected with cancer associated myositis (CAM) displayed the highest levels of circulating EVs compared to no CAM patients (p=0.0060) and to HD (p=0.0004). Patients with circulating myositis-associated autoantibodies displayed significantly higher EV levels than HD (p=0.0363). Patients in clinical remission displayed higher levels of circulating EVs compared to those with active disease (p=0.0087). EVs levels were significantly reduced in IIM patients treated with rituximab (RTX) than in patients receiving other treatments (p<0.0001). NGS analysis detected EV-miRNAs with different expression profiles between IIM (n=47) and HDs (n=49): miR-223-3p (p=0.019), miR-15a-5p (p=0.0189), miR-451a (p=0.0074), miR-486-5p (p=0.0052), miR-32-5p (p=0.0146), and miR-222-3p (p=0.0282) were up-regulated in IIM, while miR-141-3p (p=0.0313), miR-142-3p (p=0.0244), and let-7a-5p (p=0.0003) were down-regulated in IIM patients vs. HDs. Other EV-miRNAs expression varied across IIM subsets: CAM patients displayed up-regulated expression of miR-143-3p compared to non-CAM patients (p=0.0085), while miR-148a-3p (p=0.0171) and miR-335-5p (p=0.0171) were up-regulated in dermatomyositis vs. polymyositis/ inclusion body myositis/anti-synthetase syndrome patients. Patients characterized by active disease displayed an up-regulated expression of miR-222-3p (p=0.002) and miR-151-3p (p=0.0233) and down-regulated expression of miR-363-3p (p=0.0001), miR-374a-5p (p=0.0258), miR-144-3p (p=0.0170), miR-181a-5p (p=0.0037) compared to those in clinical remission. Moreover, IIM patients receiving only glucocorticoids (GC) reported up-regulated expression of miR-4433b-5p (p=0.0439), miR-92a-3p (p=0.0111), let-7f-5p (p=0.0304), and down-regulated expression of miR-27a-3p (p=0.0486) compared to patients receiving GC in combination with immunosuppressants (IS). Conclusions Our results showed significantly increased concentration of circulating EVs in IIM patients. That is confirmed within specific disease phenotypes and pharmacological treatments. EV miRNAs exhibited a differential expression profile between IIM and HD, and significant differences were outlined among IIM subsets

Extracellular Vesicles and Their Importance in Human Health

Extracellular vesicle is a wide term that involves many different types of vesicles. Almost all the cell types studied secrete vesicles to the extracellular environment related to cell - cell communication. Extracellular vesicles have been found in different biological fluids, such as blood, milk, saliva, tears, urine, and cerebrospinal fluid. These vesicles transport different molecules, including mRNA, proteins, and lipids, some of them cell type specific that make them ideal biomarkers in both health and disease conditions. However, their contribution to different conditions is not well understood. The aim of this book is to provide an overview of the extracellular vesicles in the human body, how they are internalized, and their participation in several diseases

Inflammatory actions of chemokines and extracellular versicles in pathological tissue remodeling

This thesis gives the reader the general overview on the importance of platelets and smooth muscle cells in the process of calcification of blood vessels that occurs in various pathological states, including atherosclerosis. Moreover, the mechanisms of these processes on a cellular level and the concept of reversing calcification was described. This thesis especially emphasizes the role of platelet-derived chemokines (platelet factor 4, platelet factor 4 alt and RANTES) in the remodeling of other cell types residing in the blood vessels, in particular smooth muscle cells and endothelial cells. Additionally, this thesis investigated the involvement of nanoscale vesicles, released by the liver cells (hepatocytes) in the development of liver disease such as non-alcoholic steatohepatitis (NASH) that may subsequently lead to liver fibrosis and ultimately cirrhosis. Finally, the results were critically discussed and translated to a clinically relevant context

The CXCL8/IL-8 chemokine family and its receptors in inflammatory diseases

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Assessment and modulation of the lymphatic function throughout the onset and progression of atherosclerosis

L'athérosclérose est la principale cause de maladies coronariennes, affectant les artères de grand et moyen calibre. C'est une maladie inflammatoire chronique caractérisée par des plaques situées dans la couche de l’intima, composées de cellules inflammatoires, de cellules musculaires lisses, de composants fibreux et de lipides. Qu'il provienne de source alimentaire ou hépatique, le cholestérol qui s'accumule dans les macrophages des tissus périphériques, comme la paroi artérielle, engendre une réaction inflammatoire et doit être conséquemment mobilisé à l'aide d’accepteurs de cholestérol comme les lipoprotéines de haute densité (HDL). Ce processus spécifique est appelé transport inverse du cholestérol (mRCT). Des études ont démontré que l'apolipoprotéine A-I (apoA-I) pourrait être un acteur clé dans la régulation du mRCT, exerçant des effets différents de ceux du HDL. Plus important encore, le système lymphatique a récemment été identifié comme un nouvel acteur essentiel dans l'élimination du cholestérol de la lésion athérosclérotique (Martel et al., JCI 2013). Il a été démontré que sans vaisseaux lymphatiques fonctionnels, la mobilisation du cholestérol hors de la plaque ne peut pas être réalisée correctement et aggrave la maladie. Le réseau lymphatique est parallèle au système sanguin et il est présent dans presque tous les tissus du corps. C'est un acteur essentiel dans le maintien de l'homéostase des fluides, dans le transport des cellules immunitaires de la périphérie vers les ganglions lymphatiques correspondants, ainsi que dans l’absorption des lipides alimentaires de l'intestin vers la circulation sanguine. Le système lymphatique comprend les vaisseaux lymphatiques (LVs) initiaux et collecteurs, ainsi que les ganglions lymphatiques, qui ont une anatomie spécifique et des rôles distincts. La lymphe, le liquide clair qui circule dans les LVs, se jette dans la circulation sanguine au niveau de la veine sous-clavière. Les plaquettes sont responsables de la régulation de cette séparation des vaisseaux sanguins et lymphatiques via la formation d’un thrombus formé lors de l’interaction de leur récepteur CLEC-2 avec la podoplanine présente sur les cellules endothéliales lymphatiques. Il a également été démontré que l’activité plaquettaire était nécessaire tout au long de la vie pour maintenir l’intégrité des jonctions des LVs. L'athérosclérose est également caractérisée par une activation cellulaire et une apoptose accrue. Par conséquent, ces activités cellulaires peuvent entraîner la formation de particules submicroniques appelées vésicules extracellulaires qui ont des effets variables, mais souvent néfastes, sur l'endothélium sanguin et l'évolution de la plaque. La maladie cardiovasculaire a été associée à une augmentation du nombre des vésicules extracellulaires (EVs) en circulation, et nous croyons que ces véhicules pourraient être impliqués dans le dysfonctionnement lymphatique lié à l'athérosclérose. D'après des données récentes publiées au cours de ma maîtrise, l'amélioration du transport lymphatique pourrait limiter la progression de l'athérosclérose et favoriser la régression de la plaque. Nous avons montré que le transport lymphatique est altéré chez les jeunes souris prédisposés à développer l'athérosclérose, même avant l'apparition de la plaque. Nous avons prouvé que cet effet est d’abord associé à un défaut au niveau des vaisseaux collecteurs et nous suggérons que l'amélioration de la liaison du VEGF-C/ VEGFR3 puisse supprimer ce défaut spécifique. L'objectif global de cette thèse était de poursuivre dans cette voie et de mieux définir le rôle de l’important facteur de croissance lymphatique, VEGF-C, et de la lipoprotéine apoA-I dans la maintenance de l’intégrité et la fonction des vaisseaux lymphatiques. En outre, une meilleure description des composants de la lymphe, en particulier des agents libérés par les cellules, a été jugée nécessaire. La première publication nous a permis de montrer que, lorsqu'elles étaient injectées avec un mutant du facteur de croissance VEGF-C ciblant spécifiquement le récepteur VEGFR-3 (VEGF-C 152s), avant l'administration d'une diète pro-athérogène, les souris Ldlr-/- étaient protégées contre l’accumulation excessive dans la plaque et celle-ci était plus stable à long terme. La capacité de contraction soutenue des vaisseaux lymphatiques collecteurs et l'expression accrue de VEGFR-3 et de FOXC2 observée chez ces souris traitées avec VEGF-C-152s ont contribué à la clairance des composants nocifs contenus dans les tissus périphériques tels que les macrophages et le cholestérol. La deuxième publication a montré que des souris Ldlr-/- athérosclérotiques traitées à faible dose avec de l’apoA-I, présentaient un transport lymphatique accru et une hyperperméabilité des vaisseaux lymphatiques collecteurs abrogée, possiblement par une modulation de l’activité plaquettaire. La troisième publication est la première à démontrer la présence de vésicules extracellulaires d'origines hétérogènes dans la lymphe des souris et que le nombre de différents sous-types augmente chez les souris athérosclérotiques. Collectivement, ces études confirment la présence d'un dysfonctionnement lymphatique chez la souris avant même l'apparition de la plaque, et il est intéressant de noter que ce dysfonctionnement est principalement associé à un défaut des vaisseaux lymphatiques collecteurs, limitant ainsi le transport de la lymphe des tissus périphériques vers le sang. Différents traitements avec des facteurs de croissance et des lipoprotéines peuvent potentiellement moduler l’apparition et la progression de la lésion en améliorant la fonction lymphatique à différents stades de la maladie athérosclérotique. Nos découvertes concernant la présence de EVs dans la lymphe représentent leur potentiel en tant que biomarqueurs, mais également une nouvelle cible pour mieux comprendre la dysfonction lymphatique.Atherosclerosis is the principal cause of coronary artery disease (CAD), affecting large- and medium-sized arteries. It is a chronic inflammatory disease characterized by intimal plaques composed of inflammatory cells, smooth muscle cells, fibrous components and lipids. Cholesterol that accumulates within macrophages in peripheral tissues, like the arterial wall, whether from dietary or synthetic sources, promotes inflammatory responses and needs to be excreted with the help of the cholesterol acceptor high density lipoprotein (HDL). This specific process is termed macrophage reverse cholesterol transport (mRCT) and studies have demonstrated that lipid free apolipoprotein A-I (apoA-I) could be a key player in mRCT regulation, exuding different effects than HDL. More importantly, recently, the lymphatic system has been identified as a novel prerequisite player in the removal of cholesterol out of the atherosclerotic lesion (Martel et al., JCI 2013). It has been demonstrated that without functioning lymphatic vessels cholesterol mobilization from the plaque cannot be properly achieved and aggravates the disease. The lymphatic network runs in parallel to the blood vasculature and is present in almost all the tissues of the body. It is a crucial player in maintaining fluid homeostasis, trafficking immune cells from the periphery to corresponding lymph nodes, as well as transporting lipids from the intestine to the circulation. The lymphatic system comprises the initial and collecting lymphatic vessels (LVs), as well as lymph nodes, all with a specific anatomy and distinctive roles. Lymph, the clear fluid that circulates within LVs drains towards the bloodstream at the level of the subclavian vein. Platelets are responsible to regulate this blood/lymphatic vessel separation by forming a clog, upon the interaction of their C-type lectin-like receptor 2 (CLEC-2) with podoplanin, present on lymphatic endothelial cells. Platelet activity has also been shown to be required throughout life in order to maintain LV junction integrity. Atherosclerosis is also characterized by increased cellular activation and apoptosis. Consequently, these cellular activities may result in the formation of submicron particles called extracellular vesicles (EVs) that have variable effects on the blood endothelium and subsequent plaque evolution. CAD has been associated with increased circulating EVs, and we suspect that these EVs might be involved in atherosclerosis-related lymphatic dysfunction. Based on recent data collected during my master’s degree, there is evidence that enhancing lymphatic transport could limit atherosclerosis progression and favour plaque regression. We showed that lymphatic transport is impaired in young, atherosclerosis-prone mice, even before atherosclerosis onset. We believe it to be potentially associated with a defect in the lymphatic pumping capacity, and we suggest that enhancing VEGF-C/VEGFR-3 binding can abolish this specific defect. The global objective of this thesis was to pursue along this path and better delineate the role of the important lymphatic-specific growth factor, VEGF-C and the lipoprotein apoA-I, on collecting LVs function. Furthermore, a better understanding of lymph components, especially cellular releasants was deemed necessary. The first publication allowed us to show that when injected with VEGF-C 152s, before the administration of a pro-atherogenic regimen, Ldlr-/- mice were protected from excessive plaque formation and long-term, had a more stable plaque. The sustained contraction capacity of the collecting lymphatic vessels and the enhanced expression of VEGFR-3 and FOXC2 observed in these VEGF-C-152s treated mice contributed to the clearance of harmful components contained in peripheral tissues such as the macrophages and cholesterol. The second publication showed that atherosclerotic Ldlr-/- mice treated with low-dose lipid-free apoA-I had enhanced lymphatic transport and abrogated collecting LV permeability possibly through modulation of platelet activity. The third publication is the first ever to demonstrate the presence of extracellular vesicles of heterogeneous origins in the lymph of mice, and that their levels differ in atherosclerosis. Collectively, these studies confirm that lymphatic dysfunction is present before the onset of atherosclerosis, and particularly of interest, that this dysfunction is primarily associated with a defect in the collecting vessels, thereby limiting the lymph transport from peripheral tissues to the blood. Different treatments with growth factors and lipoproteins have the potential to modulate the lesion onset and progression through the enhancement of lymphatic function, while our findings regarding the presence of EVs in lymph represents their potential as biomarkers, but also a new venue to better understand lymphatic dysfunction