scholarly journals Endoplasmic Reticulum (ER) Stress-Generated Extracellular Vesicles (Microparticles) Self-Perpetuate ER Stress and Mediate Endothelial Cell Dysfunction Independently of Cell Survival

2020 ◽  
Vol 7 ◽  
Author(s):  
Aisha Osman ◽  
Heba El-Gamal ◽  
Mazhar Pasha ◽  
Asad Zeidan ◽  
Hesham M. Korashy ◽  
...  

Circulating extracellular vesicles (EVs) are recognized as biomarkers and effectors of endothelial dysfunction, the initiating step of cardiovascular abnormalities. Among these EVs, microparticles (MPs) are vesicles directly released from the cytoplasmic membrane of activated cells. MPs were shown to induce endothelial dysfunction through the activation of endoplasmic reticulum (ER) stress. However, it is not known whether ER stress can lead to MPs release from endothelial cells and what biological messages are carried by these MPs. Therefore, we aimed to assess the impact of ER stress on MPs shedding from endothelial cells, and to investigate their effects on endothelial cell function. EA.hy926 endothelial cells or human umbilical vein endothelial cells (HUVECs) were treated for 24 h with ER stress inducers, thapsigargin or dithiothreitol (DTT), in the presence or absence of 4-Phenylbutyric acid (PBA), a chemical chaperone to inhibit ER stress. Then, MPs were isolated and used to treat cells (10–20 μg/mL) for 24–48 h before assessing ER stress response, angiogenic capacity, nitric oxide (NO) release, autophagy and apoptosis. ER stress (thapsigargin or DDT)-generated MPs did not differ quantitatively from controls; however, they carried deleterious messages for endothelial function. Exposure of endothelial cells to ER stress-generated MPs increased mRNA and protein expression of key ER stress markers, indicating a vicious circle activation of ER stress. ER stress (thapsigargin)-generated MPs impaired the angiogenic capacity of HUVECs and reduced NO release, indicating an impaired endothelial function. While ER stress (thapsigargin)-generated MPs altered the release of inflammatory cytokines, they did not, however, affect autophagy or apoptosis in HUVECs. This work enhances the general understanding of the deleterious effects carried out by MPs in medical conditions where ER stress is sustainably activated such as diabetes and metabolic syndrome.

Biomedicines ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 409
Author(s):  
Aisha Osman ◽  
Tarek Benameur ◽  
Hesham M. Korashy ◽  
Asad Zeidan ◽  
Abdelali Agouni

Upon increased demand for protein synthesis, accumulation of misfolded and/or unfolded proteins within the endoplasmic reticulum (ER), a pro-survival response is activated termed unfolded protein response (UPR), aiming at restoring the proper function of the ER. Prolonged activation of the UPR leads, however, to ER stress, a cellular state that contributes to the pathogenesis of various chronic diseases including obesity and diabetes. ER stress response by itself can result in endothelial dysfunction, a hallmark of cardiovascular disease, through various cellular mechanisms including apoptosis, insulin resistance, inflammation and oxidative stress. Extracellular vesicles (EVs), particularly large EVs (lEVs) commonly referred to as microparticles (MPs), are membrane vesicles. They are considered as a fingerprint of their originating cells, carrying a variety of molecular components of their parent cells. lEVs are emerging as major contributors to endothelial cell dysfunction in various metabolic disease conditions. However, the mechanisms underpinning the role of lEVs in endothelial dysfunction are not fully elucidated. Recently, ER stress emerged as a bridging molecular link between lEVs and endothelial cell dysfunction. Therefore, in the current review, we summarized the roles of lEVs and ER stress in endothelial dysfunction and discussed the molecular crosstalk and relationship between ER stress and lEVs in endothelial dysfunction.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Modar Kassan ◽  
Ajit Vikram ◽  
Young-Rae Kim ◽  
Qiuxia Li ◽  
Adam Kassan ◽  
...  

Abstract Sirtuin1 (Sirt1) is a class III histone deacetylase that regulates a variety of physiological processes, including endothelial function. Caveolin1 (Cav1) is also an important determinant of endothelial function. We asked if Sirt1 governs endothelial Cav1 and endothelial function by regulating miR-204 expression and endoplasmic reticulum (ER) stress. Knockdown of Sirt1 in endothelial cells, and in vivo deletion of endothelial Sirt1, induced endothelial ER stress and miR-204 expression, reduced Cav1, and impaired endothelium-dependent vasorelaxation. All of these effects were reversed by a miR-204 inhibitor (miR-204 I) or with overexpression of Cav1. A miR-204 mimic (miR-204 M) decreased Cav1 in endothelial cells. In addition, high-fat diet (HFD) feeding induced vascular miR-204 and reduced endothelial Cav1. MiR-204-I protected against HFD-induced downregulation of endothelial Cav1. Moreover, pharmacologic induction of ER stress with tunicamycin downregulated endothelial Cav1 and impaired endothelium-dependent vasorelaxation that was rescued by overexpressing Cav1. In conclusion, Sirt1 preserves Cav1-dependent endothelial function by mitigating miR-204-mediated vascular ER stress.


2020 ◽  
Vol 319 (6) ◽  
pp. E961-E980
Author(s):  
Ruixi Luo ◽  
Linzhao Li ◽  
Xiaohong Liu ◽  
Yujia Yuan ◽  
Wuzheng Zhu ◽  
...  

High levels of plasma free fatty acids (FFAs) lead to endothelial dysfunction (ED), which is involved in the pathogenesis of metabolic syndrome, diabetes, and atherosclerosis. Endoplasmic reticulum (ER) stress and endothelial-to-mesenchymal transition (EndMT) are demonstrated to be mechanistically related to endothelial dysfunction. Mesenchymal stem cells (MSCs) have exhibited an extraordinary cytoprotective effect on cellular lipotoxicity and vasculopathy. However, the underlying mechanisms have not been clearly defined. In the present study, we investigated whether MSCs could ameliorate palmitic acid (PA)-induced endothelial lipotoxicity by reducing ER stress and EndMT. We observed that MSC cocultures substantially alleviated PA-induced lipotoxicity in human umbilical vein endothelial cells (HUVECs). MSCs were able to restore the cell viability, increase tubule formation and migration ability, and decrease inflammation response and lipid deposition. Furthermore, PA caused endothelial-to-mesenchymal transition in HUVECs, which was abrogated by MSCs possibly through inhibiting ER stress. In addition, PA stimulated MSCs to secrete more stanniocalcin-1 (STC-1). Knocking down of STC-1 in MSCs attenuated their effects on PA-induced lipotoxicity in HUVECs. In vivo, MSC transplantation alleviated dyslipidemia and endothelial dysfunction in high-fat diet-fed Sprague–Dawley rats. MSC-treated rats showed reduced expressions of ER stress-related genes in aortas and suppressed expressions of EndMT-related proteins in rat aortic endothelial cells. Overall, our findings indicated that MSCs were able to attenuate endothelial lipotoxicity through inhibiting ER stress and EndMT, in which STC-1 secreted from MSCs may play a critical role.


Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1782 ◽  
Author(s):  
Zhiqiang He ◽  
Xuanhong He ◽  
Menghan Liu ◽  
Lingyue Hua ◽  
Tian Wang ◽  
...  

Atherosclerosis is the pathological basis of cardiovascular disease, whilst endothelial dysfunction (ED) plays a primary role in the occurrence and development of atherosclerosis. Simvastatin has been shown to possess significant anti-atherosclerosis activity. In this study, we evaluated the protective effect of simvastatin on endothelial cells under oxidative stress and elucidated its underlying mechanisms. Simvastatin was found to attenuate H2O2-induced human umbilical vein endothelial cells (HUVECs) dysfunction and inhibit the Wnt/β-catenin pathway; however, when this pathway was activated by lithium chloride, endothelial dysfunction was clearly enhanced. Further investigation revealed that simvastatin did not alter the expression or phosphorylation of LRP6, but reduced intracellular cholesterol deposition and inhibited endoplasmic reticulum (ER) stress. Inducing ER stress with tunicamycin activated the Wnt/β-catenin pathway, whereas reducing ER stress with 4-phenylbutyric acid inhibited it. We hypothesize that simvastatin does not affect transmembrane signal transduction in the Wnt/β-catenin pathway, but inhibits ER stress by reducing intracellular cholesterol accumulation, which blocks intracellular signal transduction in the Wnt/β-catenin pathway and ameliorates endothelial dysfunction.


2020 ◽  
Vol 21 (23) ◽  
pp. 9309
Author(s):  
Jessica Maiuolo ◽  
Rocco Mollace ◽  
Micaela Gliozzi ◽  
Vincenzo Musolino ◽  
Cristina Carresi ◽  
...  

SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection is associated, alongside with lung infection and respiratory disease, to cardiovascular dysfunction that occurs at any stage of the disease. This includes ischemic heart disease, arrhythmias, and cardiomyopathies. The common pathophysiological link between SARS-CoV-2 infection and the cardiovascular events is represented by coagulation abnormalities and disruption of factors released by endothelial cells, which contribute in maintaining the blood vessels into an anti-thrombotic state. Thus, early alteration of the functionality of endothelial cells, which may be found soon after SARS-CoV-2 infection, seems to represent the major target of a SARS CoV-2 disease state and accounts for the systemic vascular dysfunction that leads to a detrimental effect in terms of hospitalization and death accompanying the disease. In particular, the molecular interaction of SARS-CoV-2 with the ACE2 receptor located in the endothelial cell surface, either at the pulmonary and systemic level, leads to early impairment of endothelial function, which, in turn, is followed by vascular inflammation and thrombosis of peripheral blood vessels. This highlights systemic hypoxia and further aggravates the vicious circle that compromises the development of the disease, leading to irreversible tissue damage and death of people with SARS CoV-2 infection. The review aims to assess some recent advances to define the crucial role of endothelial dysfunction in the pathogenesis of vascular complications accompanying SARS-CoV-2 infection. In particular, the molecular mechanisms associated with the interaction of SARS CoV-2 with the ACE2 receptor located on the endothelial cells are highlighted to support its role in compromising endothelial cell functionality. Finally, the consequences of endothelial dysfunction in enhancing pro-inflammatory and pro-thrombotic effects of SARS-CoV-2 infection are assessed in order to identify early therapeutic interventions able to reduce the impact of the disease in high-risk patients.


2017 ◽  
Vol 113 (11) ◽  
pp. 1389-1402 ◽  
Author(s):  
Raymond Q. Migrino ◽  
Hannah A. Davies ◽  
Seth Truran ◽  
Nina Karamanova ◽  
Daniel A. Franco ◽  
...  

AbstractAimsMedin is a common amyloidogenic protein in humans that accumulates in arteries with advanced age and has been implicated in vascular degeneration. Medin’s effect on endothelial function remains unknown. The aims are to assess medin’s effects on human arteriole endothelial function and identify potential mechanisms underlying medin-induced vascular injury.Methods and resultsEx vivo human adipose and leptomeningeal arterioles were exposed (1 h) to medin (0.1, 1, or 5 µM) without or with FPS–ZM1 [100 µM, receptor for advanced glycation endproducts (RAGE)-specific inhibitor] and endothelium-dependent function (acetylcholine dilator response) and endothelium-independent function (dilator response to nitric oxide donor diethylenetriamine NONOate) were compared with baseline control. Human umbilical vein endothelial cells were exposed to medin without or with FPS–ZM1 and oxidative and nitrative stress, cell viability, and pro-inflammatory signaling measures were obtained. Medin caused impaired endothelial function (vs. baseline response: −45.2 ± 5.1 and −35.8 ± 7.9% in adipose and leptomeningeal arterioles, respectively, each P < 0.05). Dilator response to NONOate was not significantly changed. Medin decreased arteriole and endothelial cell nitric oxide production, increased superoxide production, reduced endothelial cell viability, proliferation, and migration. Medin increased gene and protein expression of interleukin-6 and interleukin-8 via activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB). Medin-induced endothelial dysfunction and oxidative stress were reversed by antioxidant polyethylene glycol superoxide dismutase and by RAGE inhibitor FPS-ZM1.ConclusionsMedin causes human microvascular endothelial dysfunction through oxidative and nitrative stress and promotes pro-inflammatory signaling in endothelial cells. These effects appear to be mediated via RAGE. The findings represent a potential novel mechanism of vascular injury.


Author(s):  
Jessica Maiuolo ◽  
Rocco Mollace ◽  
Micaela Gliozzi ◽  
Vincenzo Musolino ◽  
Cristina Carresi ◽  
...  

Abstract: SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection is associated, alongside with lung infection and respiratory disease, to cardiovascular dysfunction that occurs at any stage of the disease. This includes ischemic heart disease, arrhythmias, and cardiomyopathies. The common pathophysiological link between SARS-CoV-2 infection and the cardiovascular events is represented by coagulation abnormalities and disruption of factors released by endothelial cells which contribute in maintaining the blood vessels into an anti-thrombotic state. Thus, early alteration of the functionality of endothelial cells, which may be found soon after SARS-CoV-2 infection, seems to represent the major target of SARS CoV-2 disease state and accounts for the systemic vascular dysfunction that leads to detrimental effect in terms of hospitalization and death accompanying the disease. In particular, the molecular interaction of SARS-CoV-2 with ACE2 receptor located in endothelial cell surface, either at the pulmonary and systemic level, leads to early impairment of endothelial function which, in turn, is followed by vascular inflammation and thrombosis of peripheral blood vessels. This highlights systemic hypoxia and further aggravates the vicious circle that compromises the development of the disease leading to irreversible tissue damage and death of patients with SARS CoV-2 infection. The review aims to assess some recent advances to define the crucial role of endothelial dysfunction in the pathogenesis of vascular complications accompanying SARS-CoV-2 infection. In particular, the molecular mechanisms associated to the interaction of SARS CoV-2 with ACE2 receptor located on the endothelial cells are highlighted to support its role in compromising endothelial cell functionality. Finally, the consequences of endothelial dysfunction in enhancing pro-inflammatory and pro-thrombotic effects of SARS-CoV-2 infection are assessed in order to identify early therapeutic interventions able to reduce the impact of the disease in high-risk patients.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Abdelali Agouni ◽  
Hadj A Mostefai ◽  
Chiarra Porro ◽  
Nunzia Carusio ◽  
Julie Favre ◽  
...  

Microparticles (MPs) are small fragments generated from the plasma membrane of cells upon stimulation. Among the candidate proteins harboured by MPs, we have recently shown that Sonic Hedgehog (Shh) is present in MPs generated from activated/apoptotic human T CEM lymphocytes. MPs were isolated following serial centrifugations. Eahy 926 endothelial cells were grown for 24h in the absence or presence of 10 μg/mL MPs pre-incubated (or not) either with inhibitors of PI3-kinase (LY294002, 20 μM), MEK 1/2 (U0126, 10 μM), cyclopamine (30 μM), a specific antagonist of the Sonic Hedgehog receptor (Patched), or siRNA of Patched. Cell lysates were analyzed by Western blot. Cells were used for direct measurement of nitric oxide (NO), and oxidative stress was determined by flow cytometry. In other experiments, after 24h of intravenous injection of MPs to mice, endothelium-dependent relaxation was determined in aortic rings. In addition, ischemia/reperfusion was induced in mice by ligating the left anterior descending coronary artery proximal to its origin and endothelial function of the distal coronary artery was assessed. We show that Shh carried by MPs: a) induces NO release from endothelial cells under basal (2.5 fold) and after a bradykinin-stimulation (20 μM) conditions (2.6 fold) b) increases both the expression and the phosphorylation of enzymes related to the NO pathway, and c) decreases the production of reactive oxygen species (38.6 ± 1.4 % of positive cells in treated vs. 51.4 ± 0.2 % in control). Inhibition of PI3-kinase and ERK signalling reversed the effects of MPs. Injection of MPs to mice improved endothelial function in aorta (EC 50 ; 8.5 x 10 −8 M of acetylcholine in control vs. 7.05 x 10 −8 M in treated mice) and elevated NO release in blood, heart and lungs (1.4, 1.9 and 2.6-fold, respectively). Mice treated with Shh MPs had reduced coronary endothelial dysfunction after ischaemia/reperfusion. Silencing Shh with either cyclopamine or siRNA of Patched caused a 35 % reduction of NO release elicited by MPs. Based on our findings, we propose that the cardiovascular effects of MPs harbouring Shh may represent a new therapeutic approach against endothelial dysfunction caused by endothelial injury e.g. during cardiac ischemia.


2006 ◽  
Vol 95 (06) ◽  
pp. 1025-1030 ◽  
Author(s):  
Georg Breier ◽  
Henning Morawietz

SummaryThe 5th International Symposium on the Biology of Endothelial Cells was held in Dresden, Germany. The meeting included sessions on endothelial cell differentiation, tumor and lymph angiogenesis, endothelial cell junctions and barrier function, biomechanical control of endothelial function, oxidative stress and endothelial dysfunction, hypoxia and VEGF-induced signaling, inflammation and angiogenesis. This report summarizes the key findings of the platform presentations of the meeting.


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