Protein Expression In Endothelial Cells Research Articles

Pseudomonas aeruginosa N-3-Oxododecanoyl Homoserine Lactone Disrupts Endothelial Integrity by Activating the Angiopoietin-Tie System.

The activation of the angiopoietin (Angpt)-Tie system is linked to endothelial dysfunction during sepsis. Bacterial quorum-sensing molecules function as pathogen-associated molecular patterns. However, their impact on the endothelium and the Angpt-Tie system remains unclear. Therefore, this study investigated whether treatment with N-3-oxododecanoyl homoserine lactone (3OC12-HSL), a quorum-sensing molecule derived from Pseudomonas aeruginosa, impaired endothelial function in human umbilical vein endothelial cells. 3OC12-HSL treatment impaired tube formation even at sublethal concentrations, and immunocytochemistry analysis revealed that it seemed to reduce vascular endothelial-cadherin expression at the cell-cell interface. Upon assessing the mRNA expression patterns of genes associated with the Angpt-Tie axis, the expressions of Angpt2, Forkhead box protein O1, Tie1, and vascular endothelial growth factor 2 were found to be upregulated in the 3OC12-HSL-treated cells. Moreover, western blot analysis revealed that 3OC12-HSL treatment increased Angpt2 expression. A co-immunoprecipitation assay was conducted to assess the effect of 3OC12-HSL on the IQ motif containing GTPase activating protein 1 (IQGAP1) and Rac1 complex and the interaction between these proteins was consistently maintained regardless of 3OC12-HSL treatment. Next, recombinant human (rh)-Angpt1 was added to assess whether it modulated the effects of 3OC12-HSL treatment. rh-Angpt1 addition increased cellular viability, improved endothelial function, and reversed the overall patterns of mRNA and protein expression in endothelial cells treated with 3OC12-HSL. Additionally, it was related to the increased expression of phospho-Akt and the IQGAP1 and Rac1 complex. Collectively, our findings indicated that 3OC12-HSL from Pseudomonas aeruginosa can impair endothelial integrity via the activation of the Angpt-Tie axis, which appeared to be reversed by rh-Angpt1 treatment.

Hollow Copper Sulfide Photothermal Nanodelivery Platform Boosts Angiogenesis of Diabetic Wound by Scavenging Reactive Oxygen Species.

Sharply rising oxidative stress and ineffectual angiogenesis have imposed restrictions on diabetic wound healing. Here, a photothermal-responsive nanodelivery platform (HHC) was prepared by peroxidase (CAT)-loaded hollow copper sulfide dispersed in photocurable methacrylamide hyaluronan. The HHC could scavenge reactive oxygen species (ROS) and promote angiogenesis by photothermally driven CAT and Cu2+ release. Under near-infrared light irradiation, the HHC presented safe photothermal performance (<43 °C), efficient bacteriostatic ability against E. coli and S. aureus. It could rapidly release CAT into the external environment for decomposing H2O2 and oxygen generation to alleviate oxidative stress while promoting fibroblast migration and VEGF protein expression of endothelial cells by reducing intracellular ROS levels. The nanodelivery platform presented satisfactory therapeutic effects on murine diabetic wound healing by modulating tissue inflammation, promoting collagen deposition and increasing vascularization in the neodermis. This HHC provided a viable strategy for diabetic wound dressing design.

Increased 12/15-lipoxygenase by disturbed flow promotes endothelial dysfunction and the development of atherosclerosis

Abstract Introduction Atherosclerosis is predisposed at bifurcations, branch points and arterial curvatures where the blood flow is disturbed. Deposition and oxidative modification of low-density lipoprotein (LDL) in the subendothelial intima is an early event in the pathogenesis of atherosclerosis. However, the effect of disturbed flow (d-flow) on LDL oxidation and the underlying mechanisms remain unclear. Purpose In this study, we investigated the role of 12/15-lipoxygenase (LOX) in LDL oxidation in endothelial cells (EC) and the development of atherosclerosis at d-flow sites. Methods En face immunofluorescence was performed to analyze the expression of 12/15-LOX in EC under exposure to different flow patterns. Protein expression and LDL oxidation was studied in vitro by using 2 different flow apparatuses. Animal model of d-flow was established by partial ligation of the carotid artery. Results En face staining exhibited a significant increase in 12/15-LOX protein expression in EC in areas exposed to d-flow than those exposed to steady flow (s-flow). Carotid partial ligation in ApoE knockout mice led to substantially increased deposition of oxidized LDL in the subendothelial intima and formation of atherosclerotic plaques in the carotid artery, whereas these detrimental effects by d-flow were markedly attenuated in ApoE/12/15-LOX double knockout mice. In cultured EC, d-flow generated by a reversal flow pump markedly promoted the expression of 12/15-LOX and translocation of the protein onto the cell membrane. Inhibition of 12/15-LOX in EC, either by knockdown with its specific siRNA or a pharmacological inhibitor, suppressed production of 15s-HETE and LDL oxidation in response to d-flow. Mechanically, we found d-flow induced the expression of 12/15-LOX by activating a specific responsive element in the 12/15-LOX promoter through recruiting a shear stress-sensitive transcriptional factor SREBP2. Chromatin immunoprecipitation further confirmed the interaction of SREBP2 with the promoter of 12/15-LOX upon d-flow exposure. Conclusions These data define an essential role of 12/15-LOX in promoting the pathogenesis of atherosclerosis under d-flow by increasing LDL oxidation in EC through SREBP2 signaling.

Gene Expression Changes in Cytokine and Chemokine Receptors in Association with Melanoma Liver Metastasis.

Cytokines and chemokines (chemotactic cytokines) are soluble extracellular proteins that bind to specific receptors and play an integral role in the cell-to-cell signaling network. In addition, they can promote the homing of cancer cells into different organs. We investigated the potential relationship between human hepatic sinusoidal endothelial cells (HHSECs) and several melanoma cell lines for the expression of chemokine and cytokine ligands and receptor expression during the invasion of melanoma cells. In order to identify differences in gene expression related to invasion, we selected invasive and non-invasive subpopulations of cells after co-culturing with HHSECs and identified the gene expression patterns of 88 chemokine/cytokine receptors in all cell lines. Cell lines with stable invasiveness and cell lines with increased invasiveness displayed distinct profiles of receptor genes. Cell lines with increased invasive capacity after culturing with conditioned medium showed a set of receptor genes (CXCR1, IL1RL1, IL1RN, IL3RA, IL8RA, IL11RA, IL15RA, IL17RC, and IL17RD) with significantly different expressions. It is very important to emphasize that we detected significantly higher IL11RA gene expression in primary melanoma tissues with liver metastasis as well, compared to those without metastasis. In addition, we assessed protein expression in endothelial cells before and after co-culturing them with melanoma cell lines by applying chemokine and cytokine proteome arrays. This analysis revealed 15 differentially expressed proteins (including CD31, VCAM-1, ANGPT2, CXCL8, and CCL20) in the hepatic endothelial cells after co-culture with melanoma cells. Our results clearly indicate the interaction between liver endothelial and melanoma cells. Furthermore, we assume that overexpression of the IL11RA gene may play a key role in organ-specific metastasis of primary melanoma cells to the liver.

Interferon-β alleviates sepsis by SIRT1-mediated blockage of endothelial glycocalyx shedding

Sepsis is a life-threatening multi-organ dysfunction with high mortality caused by the body's improper response to microbial infection. No new effective therapy that can adequately treat patients with sepsis has emerged. We previously demonstrated that interferon-beta (IFN-β) protects against sepsis via sirtuin 1- (SIRT1)-mediated immunosuppression. Another study also reported its significant protective effect against acute respiratory distress syndrome, a complication of severe sepsis, in human patients. However, the IFN-β effect cannot solely be explained by SIRT1-mediated immunosuppression since sepsis induces immunosuppression in patients. Here, we show that IFN-β, in combination with nicotinamide riboside (NR), alleviates sepsis by blocking endothelial damage via SIRT1 activation. IFN-β plus NR protected against cecal ligation puncture- (CLP)-induced sepsis in wild-type mice, but not in endothelial cell-specific Sirt1 knockout (EC-Sirt1 KO) mice. IFN-β upregulated SIRT1 protein expression in endothelial cells in a protein synthesis-independent manner. IFN-β plus NR reduced the CLP-induced increase in in vivo endothelial permeability in wild-type but not EC-Sirt1 KO mice. IFN-β plus NR suppressed the lipopolysaccharide-induced upregulation of heparinase 1, but the effect was abolished by Sirt1 knockdown in endothelial cells. Our results suggest that IFN-β plus NR protects against endothelial damage during sepsis via activating the SIRT1/heparinase 1 pathway.

Differential protein expression in endothelial cells exposed to serum from patients with acute graft-vs-host disease, depending on steroid response.

Graft-versus-host disease (GVHD) is a complication of allogeneic haematopoietic cell transplantation. Endothelial injury is crucial as pathophysiological substrate for GVHD. GVHD first-line treatment is high-dose corticosteroids, although some patients are steroid-refractory. Through the present study, we compared the endothelial proteomic profiles in response to serum from steroid-refractory acute GVHD (SR-aGVHD) and steroid-sensitive acute GVHD (SS-aGVHD) patients. Blood samples from SR-aGVHD (n= 4) and SS-aGVHD (n= 8) patients were collected at aGVHD diagnosis. Endothelial cell cultures were exposed (48 h) to patients' serum. Protein extraction and proteomic analysis were performed. Differences were statistically evaluated by multivariate analysis. Forty-four proteins contributed to separate all samples into the two study groups, among which 15 participated significantly (p< 0.05), 10 exhibiting a fold change >1.2. Differentially expressed proteins were mainly associated with oxidative phosphorylation (Cytochrome C oxidase subunit 6B1, CX6B1), inflammation and angiogenesis (Apolipoprotein D, APOD), cell survival (Rapamycin-insensitive companion of mTOR, RICTR), and oxidative stress (Riboflavin kinase, RIFK). This pilot study used a novel approach to distinguish the aGVHD response to steroid treatment. The proteins differentially expressed could constitute potential biomarkers for steroid-treatment response. These findings signify a step forward to identify the mechanisms of response to steroids, of high clinical relevance considering the SR-aGVHD elevated mortality.

Tissue Derivation and Biological Sex Uniquely Mediate Endothelial Cell Protein Expression, Redox Status, and Nitric Oxide Synthesis.

Human endothelial cells are routinely utilized in cardiovascular research to provide a translational foundation for understanding how the vascular endothelium functions in vivo. However, little attention has been given to whether there are sex specific responses in vitro. Similarly, it is unclear whether endothelial cells derived from distinct tissues behave in a homogenous manner. Herein, we demonstrate that marked sex differences exist within, and between, commonly utilized human primary endothelial cells from healthy donors, with respect to redox status, nitric oxide synthesis, and associated proteins that can mediate their expression. Further, we demonstrate that endothelial cells respond uniquely to inflammatory insult in a sex- and tissue origin-dependent manner. Our findings suggest sex and tissue derivation may need to be considered when studying endothelial cells in vitro as cells derived from distinct tissue and sexes may not behave interchangeably.

INCREASED EICOSAPENTAENOIC ACID TO ARACHIDONIC ACID (EPA/AA) RATIO IN BRAIN ENDOTHELIAL CELLS ASSOCIATED WITH REDUCED EXPRESSION OF NEUTROPHIL DEGRANULATION PROTEINS DURING INFLAMMATION

Endothelial cell (EC) dysfunction results in inflammation and increased atherothrombotic risk, including stroke. The omega-3 fatty acid (FA) eicosapentaenoic acid (EPA) improves arterial compliance in a manner predicted by circulating EPA/AA ratios, an indicator of cardiovascular (CV) risk. Treatment with icosapent ethyl (IPE), a formulation of highly purified EPA, reduced composite CV events, including stroke, in REDUCE-IT that correlated with on-treatment EPA levels. We measured the effects of EPA on the EPA/AA ratio and protein expression in endothelial cells from brain ECs (BECs) following cytokine challenge.

Robust therapeutic effects on COVID-19 of novel small molecules: Alleviation of SARS-CoV-2 S protein induction of ACE2/TMPRSS2, NOX2/ROS, and MCP-1.

While new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) constantly emerge to prolong the pandemic of COVID-19, robust and safe therapeutics are in urgent need. During the previous and ongoing fight against the pandemic in China, Traditional Chinese Medicine (TCM) has proven to be markedly effective in treating COVID-19. Among active ingredients of TCM recipes, small molecules such as quercetin, glabridin, gallic acid, and chrysoeriol have been predicted to target viral receptor angiotensin-converting enzyme 2 (ACE2) via system pharmacology/molecular docking/visualization analyses. Of note, endothelial dysfunction induced by oxidative stress and inflammation represents a critical mediator of acute respiratory distress syndrome (ARDS) and multi-organ injuries in patients with COVID-19. Hence, in the present study, we examined whether quercetin, glabridin, gallic acide and chrysoeriol regulate viral receptors of ACE2 and transmembrane serine protease 2 (TMPRSS2), redox modulator NADPH oxidase isoform 2 (NOX2), and inflammatory protein of monocyte chemoattractant protein-1 (MCP-1) in endothelial cells to mediate therapeutic protection against COVID-19. Indeed, quercetin, glabridin, gallic acide and chrysoeriol completely attenuated SARS-CoV-2 spike protein (S protein)-induced upregulation in ACE2 protein expression in endothelial cells. In addition, these small molecules abolished S protein upregulation of cleaved/active form of TMPRSS2, while native TMPRSS2 was not significantly regulated. Moreover, these small molecules completely abrogated S protein-induced upregulation in NOX2 protein expression, which resulted in alleviated superoxide production, confirming their preventive efficacies against S protein-induced oxidative stress in endothelial cells. In addition, treatment with these small molecules abolished S protein induction of MCP-1 expression. Collectively, our findings for the first time demonstrate that these novel small molecules may be used as novel and robust therapeutic options for the treatment of patients with COVID-19, via effective attenuation of S protein induction of endothelial oxidative stress and inflammation.

The Peptide/Antibody-Based Surface Decoration of Calcium Phosphate Nanoparticles Carrying siRNA Influences the p65 NF-κB Protein Expression in Inflamed Cells In Vitro.

Earlier studies with nanoparticles carrying siRNA were restricted to investigating the inhibition of target-specific protein expression, while almost ignoring effects related to the nanoparticle composition. Here, we demonstrate how the design and surface decoration of nanoparticles impact the p65 nuclear factor-kappa B (NF-κB) protein expression in inflamed leucocytes and endothelial cells in vitro. We prepared silica-coated calcium phosphate nanoparticles carrying encapsulated siRNA against p65 NF-κB and surface-decorated with peptides or antibodies. We show that RGD-decorated nanoparticles are efficient in down-regulating p65 NF-κB protein expression in endothelial cells as a result of an enhanced specific cellular binding and subsequent uptake of nanoparticles. In contrast, nanoparticles decorated with IgG (whether specific or not for CD69) are efficient in down-regulating p65 NF-κB protein expression in T-cells, but not in B-cells. Thus, an optimized nanoparticle decoration with xenogenic IgG may stimulate a specific cellular uptake. In summary, the composition of siRNA-loaded calcium phosphate nanoparticles can either weaken or stimulate p65 NF-κB protein expression in targeted inflamed leucocytes and endothelial cells. In general, unveiling such interactions may be very useful for the future design of anti-p65 siRNA-based nanomedicines for treatment of inflammation-associated diseases.

Resveratrol attenuates atherosclerotic endothelial injury through the Pin1/Notch1 pathway

The present study investigates whether resveratrol could modulate the endothelial dysfunction of atherosclerosis via the Pin1/Notch1 signaling pathway. To assess the vascular endothelial cell (VECs) injury in mice, the levels of serum soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), soluble E-selectin (sE-selectin), soluble thrombomodulin (sTM), and von Willebrand factor (vWF) were measured. Expressions of Pin1 and Notch1 intracellular domain (NICD1), both mRNA and protein, were also measured. Human umbilical vein endothelial cells (HUVECs) treated with 100 μg/mL oxidized low-density lipoprotein (ox-LDL) were incubated with resveratrol at doses from 10 μM to 40 μM. Cell function was evaluated by measuring apoptosis, cell viability, lipid accumulation, and adherent human myeloid leukemia mononuclear (THP-1) cells. Resveratrol intervention in AS mice decreased the expression of serum sVCAM-1, sICAM-1, sE-selectin, sTM, and vWF and dose-dependently down-regulated Pin1 and NICD1 mRNA and protein expression in endothelial cells. Resveratrol intervention reversed ox-LDL-induced cell dysfunction by increasing viability and decreasing apoptosis, lipid accumulation, and the adhesion of THP-1 cells. These beneficial effects were reversed by the overexpression of Pin1. Resveratrol regulates endothelial cell injury of atherosclerosis by inhibiting the Pin1/Notch1 signaling pathway, suggesting novel therapeutic targets for atherosclerosis treatment.

Exosomal HMGA2 protein from EBV-positive NPC cells destroys vascular endothelial barriers and induces endothelial-to-mesenchymal transition to promote metastasis

Increased vascular permeability facilitates metastasis. Cancer-secreted exosomes are emerging mediators of cancer-host crosstalk. Epstein-Barr virus (EBV), identified as the first human tumor-associated virus, plays a crucial role in metastatic tumors, especially in nasopharyngeal carcinoma (NPC). To date, whether and how exosomes from EBV-infected NPC cells affect vascular permeability remains unclear. Here, we show that exosomes from EBV-positive NPC cells, but not exosomes from EBV-negative NPC cells, destroy endothelial cell tight junction (TJ) proteins, which are natural barriers against metastasis, and promote endothelial-to-mesenchymal transition (EndMT) in endothelial cells. Proteomic analysis revealed that the level of HMGA2 protein was higher in exosomes derived from EBV-positive NPC cells compared with that in exosomes derived from EBV-negative NPC cells. Depletion of HMGA2 in exosomes derived from EBV-positive NPC cells attenuates endothelial cell dysfunction and tumor cell metastasis. In contrast, exosomes from HMGA2 overexpressing EBV-negative NPC cells promoted these processes. Furthermore, we showed that HMGA2 upregulates the expression of Snail, which contributes to TJ proteins reduction and EndMT in endothelial cells. Moreover, the level of HMGA2 in circulating exosomes is significantly higher in NPC patients with metastasis than in those without metastasis and healthy negative controls, and the level of HMGA2 in tumor cells is associated with TJ and EndMT protein expression in endothelial cells. Collectively, our findings suggest exosomal HMGA2 from EBV-positive NPC cells promotes tumor metastasis by targeting multiple endothelial TJ and promoting EndMT, which highlights secreted HMGA2 as a potential therapeutic target and a predictive marker for NPC metastasis.

N6-Methyladenosine Demethylase FTO (Fat Mass and Obesity-Associated Protein) as a Novel Mediator of Statin Effects in Human Endothelial Cells.

N6-methyladenosine (m6A) plays a critical role in various biological processes. However, no study has addressed the role of m6A modification in the statin-induced protection of endothelial cells (ECs). Quantitative real-time polymerase chain reaction and Western blotting analyses were used to study the expression of m6A regulatory genes in atorvastatin-treated ECs. Gain- and loss-of-function assays, methylated RNA immunoprecipitation analysis, and dual-luciferase reporter assays were performed to clarify the function of FTO (fat mass and obesity-associated protein) in ECs. Atorvastatin decreased FTO protein expression in ECs. The knockdown of FTO enhanced the mRNA and protein expression of KLF2 (Kruppel-like factor 2) and eNOS (endothelial NO synthase) but attenuated TNFα (tumor necrosis factor alpha)-induced VCAM-1 (vascular cell adhesion molecule 1) and ICAM-1 (intercellular adhesion molecule 1) expression, as well as the adhesion of monocytes to ECs. Conversely, FTO overexpression significantly upregulated the mRNA and protein levels of VCAM-1 and ICAM-1, downregulated those of KLF2 and eNOS, and strongly attenuated the atorvastatin-mediated induction of KLF2 and eNOS expression. Subsequent investigations demonstrated that KLF2 and eNOS are functionally critical targets of FTO. Mechanistically, FTO interacted with KLF2 and eNOS transcripts and regulated their expression in an m6A-dependent manner. After FTO silencing, KLF2 and eNOS transcripts with higher levels of m6A modification in their 3' untranslated regions were captured by YTHDF3 (YT521-B homology m6A RNA-binding protein 3), resulting in mRNA stabilization and the induction of KLF2 and eNOS protein expression. FTO might serve as a novel molecular target to modulate endothelial function in vascular diseases.

Integrin Beta 4E Promotes Endothelial Phenotypic Changes and Attenuates Lung Endothelial Cell Inflammatory Responses.

We previously reported integrin beta 4 (ITGB4) is an important mediator of lung vascular protection by simvastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A-reductase inhibitor. In this study, we report increased endothelial cell (EC) expression specifically of ITGB4E, an ITGB4 mRNA splice variant, by simvastatin with effects on EC protein expression and inflammatory responses. In initial experiments, human pulmonary artery ECs were treated using simvastatin (5 μM, 24 h) prior to immunoprecipitation of integrin alpha 6 (ITGA6), which associates with ITGB4, and Western blotting for full-length ITGB4 and ITGB4E, uniquely characterized by a truncated 114 amino acid cytoplasmic domain. These experiments confirmed a significant increase in both full-length ITGB4 and ITGB4E. To investigate the effects of increased ITGB4E expression alone, ECs were transfected with ITGB4E or control vector, and cells were seeded in wells containing Matrigel to assess effects on angiogenesis or used for scratch assay to assess migration. Decreased angiogenesis and migration were observed in ITGB4E transfected ECs compared with controls. In separate experiments, PCR and Western blots from transfected cells demonstrated significant changes in EC protein expression associated with increased ITGB4E, including marked decreases in platelet endothelial cell adhesion molecule-1 (PECAM-1) and vascular endothelial-cadherin (VE-cadherin) as well as increased expression of E-cadherin and N-cadherin along with increased expression of the Slug and Snail transcription factors that promote endothelial-to-mesenchymal transition (EndMT). We, then, investigated the functional effects of ITGB4E overexpression on EC inflammatory responses and observed a significant attenuation of lipopolysaccharide (LPS)-induced mitogen-activated protein kinase (MAPK) activation, including decreased phosphorylation of both extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), as well as reduced inflammatory cytokines (IL-6 and IL-8), expressed in the media of EC after either LPS or excessive cyclic stretch (CS). Finally, EC expression-increased ITGB4E demonstrated decreased barrier disruption induced by thrombin as measured by transendothelial electrical resistance. Our data support distinct EC phenotypic changes induced by ITGB4E that are also associated with an attenuation of cellular inflammatory responses. These findings implicate ITGB4E upregulation as an important mediator of lung EC protection by statins and may lead to novel therapeutic strategies for patients with or at risk for acute lung injury (ALI).

Differential action of pro-angiogenic and anti-angiogenic components of Danhong injection in ischemic vascular disease or tumor models

ObjectiveWe investigate the chemical basis and mechanism of angiogenesis regulation by a multicomponent Chinese medicine Danhong injection (DHI).MethodsDHI was fractionated and screened for angiogenesis activities by in vitro tube formation and migration assays. The composition of DHI components was determined by UPLC. The effects of the main active monomers on angiogenesis-related gene and protein expression in endothelial cells were determined by qPCR and Western blotting analyses. Mouse hind limb ischemia and tumor implant models were used to verify the angiogenesis effects in vivo by Laser Doppler and bioluminescent imaging, respectively.ResultsTwo distinct chemical components, one promoting (pro-angiogenic, PAC) and the other inhibiting (anti-angiogenic, AAC) angiogenesis, were identified in DHI. PAC enhanced angiogenesis and improved recovery of ischemic limb perfusion while AAC reduced Lewis lung carcinoma growth in vivo in VEGFR-2-Luc mice. Among the PAC or AAC monomers, caffeic acid and rosmarinic acid upregulated TSP1 expression and downregulated KDR and PECAM expression. Caffeic acid and rosmarinic acid significantly decreased while protocatechuic aldehyde increased CXCR4 expression, which are consistent with their differential effects on EC migration.ConclusionsDHI is capable of bi-directional regulation of angiogenesis in disease-specific manner. The pro-angiogenesis activity of DHI promotes the repair of ischemic vascular injury, whereas the anti-angiogenesis activity inhibits tumor growth. The active pro- and anti-angiogenesis activities are composed of unique chemical combinations that differentially regulate angiogenesis-related gene networks.

Eicosapentaenoic Acid Increases Vascular and Pulmonary Endothelial Ferritin Levels with Enhanced Heme Oxygenase-1 Expression during Inflammation

Lead Author's Financial Disclosures Nothing to disclose. Study Funding Amarin Pharma Inc. and Elucida Research LLC. Background/Synopsis Inducible heme oxygenase-1 (HO-1) catalyzes the degradation of heme into biliverdin, carbon monoxide, and ferrous iron. Increased free iron triggers production of intracellular ferritin. Ferritin as well as the other HO-1 products have potent antioxidant, vasodilatory and anti-inflammatory actions. Unlike trials using mixed omega-3 formulations, eicospentaenoic acid (EPA) only treatment (icosapent ethyl) was associated with reduced cardiovascular (CV) events in high-risk patients with elevated triglycerides (REDUCE-IT) but the mechanism is not fully understood. Objective/Purpose This study compared the treatment effects of EPA on protein expression in endothelial cells (ECs) isolated from vein and pulmonary tissue under conditions of inflammation using the cytokine IL-6. Methods Human umbilical vein endothelial cells (HUVECs) and pulmonary microvascular ECs were first challenged with IL-6 (12 ng/mL) for 2 hours, and then treated with EPA (40 micromolar) for 24 hours. Proteomic analysis was performed using LC/MS to measure relative expression levels of >1,000 proteins simultaneously. Only significant (p<0.05) changes in expression between treatment groups >1-fold were included in the analysis. Results Cells treated with EPA significantly down/up-regulated expression of 310/276 and 212/229 proteins in vascular and pulmonary ECs, respectively, compared with IL-6 alone. In particular, EPA increased levels of HO-1 by 220% (p = 7.9E-50) and 190% (p = 2.8E-32) in vascular and pulmonary ECs, respectively. Increased HO-1 expression resulted in increased levels of ferritin light chain by 120% (p = 4.0E10-5) and 110% (p = 0.049) in vascular and pulmonary ECs, respectively, and ferritin heavy chain by 110% (p = 0.0002) and 160% (p = 1.4E10-6), respectively. Conclusions EPA increased expression of HO-1, a protein that has broad atheroprotective benefits, in both vascular and pulmonary ECs that correlated with increased ferritin levels during inflammation. The ability of EPA to enhance cytoprotective proteins has therapeutic implications for patients at risk for CV disease. Nothing to disclose.

Abstract 11596: Amyloidogenic Medin Induces Endothelial Cell Prothrombotic Activation

Background: Vascular aging is characterized by acquisition of a pro-inflammatory and prothrombotic vascular phenotype independent of cardiovascular metabolic risk factors through still unknown mechanisms. Medin is an amyloidogenic peptide formed as a cleavage product of milk fat globule EGF factor 8 protein. It accumulates in the vasculature with aging and is one of the most common yet poorly understood human amyloid proteins. Cerebrovascular medin was shown to be strongly associated with vascular dementia and Alzheimer’s disease. It was shown to induce endothelial pro-inflammatory activation and endothelial dysfunction. We aim to test the hypothesis that medin induces prothrombotic activation in endothelial cells. Methods: Recombinant medin was expressed in Lemo 21 (DE3 cells) and purified. Human umbilical vein endothelial cells (HUVECs) were exposed to either vehicle or medin (5 μM, a dose found to be physiologically relevant in human tissue) for 20 hours. Cell lysates were measured for protein content of tissue factor (TF, receptor and cofactor for factor VII and initiates coagulation), plasminogen activator inhibitor-1 (PAI-1, inhibits plasminogen activators that promote fibrinolysis) and thrombomodulin (cell surface glycoprotein that inhibits procoagulant function of thrombin) using standard Western blot and compared. Results: See Figure. Physiologic dose of medin induced increased endothelial cell protein expression of TF, PAI-1 and reduced expression of thrombomodulin. Conclusions: Medin induces prothrombotic activation in human endothelial cells and may be a key novel mediator in the development of vascular aging phenotype.

Angiotensin II-induced upregulation of SGLT1 and 2 contributes to human microparticle\u2010stimulated endothelial senescence and dysfunction: protective effect of gliflozins

BackgroundSodium-glucose cotransporter 2 (SGLT2) inhibitors reduced cardiovascular risk in type 2 diabetes patients independently of glycemic control. Although angiotensin II (Ang II) and blood-derived microparticles are major mediators of cardiovascular disease, their impact on SGLT1 and 2 expression and function in endothelial cells (ECs) and isolated arteries remains unclear.Methods ECs were isolated from porcine coronary arteries, and arterial segments from rats. The protein expression level was assessed by Western blot analysis and immunofluorescence staining, mRNA levels by RT-PCR, oxidative stress using dihydroethidium, nitric oxide using DAF-FM diacetate, senescence by senescence-associated beta-galactosidase activity, and platelet aggregation by aggregometer. Microparticles were collected from blood of patients with coronary artery disease (CAD-MPs).ResultsAng II up-regulated SGLT1 and 2 protein levels in ECs, and caused a sustained extracellular glucose- and Na+-dependent pro-oxidant response that was inhibited by the NADPH oxidase inhibitor VAS-2780, the AT1R antagonist losartan, sotagliflozin (Sota, SGLT1 and SGLT2 inhibitor), and empagliflozin (Empa, SGLT2 inhibitor). Ang II increased senescence-associated beta-galactosidase activity and markers, VCAM-1, MCP-1, tissue factor, ACE, and AT1R, and down-regulated eNOS and NO formation, which were inhibited by Sota and Empa. Increased SGLT1 and SGLT2 protein levels were observed in the rat aortic arch, and Ang II- and eNOS inhibitor-treated thoracic aorta segments, and were associated with enhanced levels of oxidative stress and prevented by VAS-2780, losartan, Sota and Empa. CAD-MPs promoted increased levels of SGLT1, SGLT2 and VCAM-1, and decreased eNOS and NO formation in ECs, which were inhibited by VAS-2780, losartan, Sota and Empa.ConclusionsAng II up-regulates SGLT1 and 2 protein expression in ECs and arterial segments to promote sustained oxidative stress, senescence and dysfunction. Such a sequence contributes to CAD-MPs-induced endothelial dysfunction. Since AT1R/NADPH oxidase/SGLT1 and 2 pathways promote endothelial dysfunction, inhibition of SGLT1 and/or 2 appears as an attractive strategy to enhance the protective endothelial function.

Interleukin-1β induces pericyte apoptosis via the NF-κB pathway in diabetic retinopathy

Pericytes play a crucial role in preventing endothelial permeability by maintaining the integrity of tight junctions in endothelial cells; however, early pathological change in diabetic retinopathyis pericyte loss, which can lead to visual impairment by increasing endothelial permeability. Therefore, finding proteins and mechanisms that cause pericyte loss in diabetic retinopathy is beneficial for attenuating vision impairment. The present study focused on the effect of IL-1β on pericyte loss and endothelial permeability in diabetic retinopathy. It was demonstrated that IL-1β increased in the diabetic mouse retina and that the source of IL-1β could be endothelial cells and microglia. IL-1β induced pericyte apoptosis via NF-κB activation under high glucose conditions, but did not induce endothelial cell apoptosis. Moreover, IL-1β did not affect permeability in the endothelial cell monolayer; however, when cocultured with pericytes and endothelial cells, it increased endothelial cell permeability by reducing the amount of tight junction protein in endothelial cells. Furthermore, NF-κB inhibitor restored the altered permeability and tight junction protein expression in endothelial cells induced by IL-1β in cocultures of pericytes and endothelial cells. Collectively, IL-1β induced pericyte apoptosis via NF-κB activation under high glucose conditions, thereby increasing endothelial permeability in diabetic retinopathy. Blocking IL-1β/NF-κB signaling could be a promising therapeutic target to prevent pericyte loss in diabetic retinopathy.

Abstract 528: Towards Therapeutic Genome Editing in Vascular Endothelium by Novel Nanoparticle Delivery of Crispr Plasmid Dna

Introduction: Therapeutic delivery of CRISPR system components to induce in vivo genome editing in postnatal and adult life has great translational potential. Recent studies employing non-viral delivery of small guide RNA (gRNA) and Cas9 mRNA have achieved efficient genome editing in adult mice. However, as often seen in other RNA therapeutic studies with non-viral delivery of antisense and siRNA, the efficiency is limited to the liver. Hypothesis: Novel nanoparticle can therapeutically deliver the CRISPR system to selectively target cardiovascular endothelium in adult mice. Methods: We developed novel PLGA-based nanoparticles which was for the first time shown to be uptaken efficiently by the vascular endothelium without specific liver accumulation following i.v. administration. Mixture of the nanoparticle:plasmid DNA expressing Cas9 under the control of the human CDH5 promoter (EC-specific) and gRNA by the U6 promoter was administered i.v. to adult mice. Seven to ten days later, various organ tissues were collected for analysis of the efficiency of genomic editing and knockout of protein expression. The phenotype of CRISPR-mediated in vivo knockout of Pik3cg which encodes the G protein-coupled receptor-activated p110gamma isoform of PI3K was compared to Pik3cg null mice in response to sepsis challenge. Results: Therapeutic delivery of nanoparticles loaded with the all-in-one CRISPR plasmid DNA induced highly efficient genome editing in endothelial cells (ECs) of the cardiovascular system including heart, lung, and aorta in adult mice. The Indel rate was as great as 50% in ECs isolated from these vascular beds. Immunostaining and Western blotting demonstrated greater than 70% decrease of protein expression in ECs. Pik3cg -gRNA-induced genome editing diminished p110γPI3K expression in pulmonary vascular ECs, which led to impaired vascular repair and resolution of inflammation after sepsis challenge as seen in Pik3cg -/- mice. Conclusion: We have developed a simple and highly efficient method for in vivo genome editing selectively targeting the vascular endothelium. This strategy will greatly facilitate cardiovascular research and may enable therapeutic genome editing for prevention and treatment of cardiovascular diseases.