Selenium Inhibits Homocysteine-Induced Endothelial Dysfunction and Apoptosis via Activation of AKT

Background/Aims: Endothelial cells are crucial in vascular homeostasis. Dysfunction of endothelial cells is involved in the development of cardiovascular diseases (CVD). High plasma homocysteine (Hcy) correlates with CVD while selenium supplementation counteracts development of CVD. However, the underlying mechanism remained unclear. Here, we investigated the effects of selenium on homocysteine-induced endothelial dysfunction. Methods: An animal model of Hcy-induced endothelial dysfunction was established by intragastric administration of L-methionine. Plasma NO and von Willebrand factor (vWF) were quantified using NO assay and ELISA kit respectively. Relaxation was measured in thoracic aortic ring assays. Cell viability and migration were detected by Cell Counting Kit-8 and Bio-Coat cell migration chambers respectively. Cellular apoptosis was determined by Annexin V-FITC apoptosis kit. Results: Selenium prevented homocysteine-induced endothelial injury and impairment of endothelium-dependent relaxation. Selenium reversed the impaired viability and migration of endothelial cells induced by homocysteine in a dose-dependent manner. Selenium inhibited the apoptosis of endothelial cells induced by homocysteine, through downregulating of Caspase-3 activity and expression of Caspase-3 and Bax, and by stimulating Bcl-2 expression. Selenium reversed the homocysteine-induced reduction of NO release, and increased the expression and phosphoylation of endothelial nitric oxide synthetase (eNOS) in a dose-dependent manner. Moreover, selenium enhanced AKT phosphorylation, and selenium-induced phosphorylation and expression of eNOS were inhibited by AKT inhibition. NO production, cell viability and migration rescued by selenium were inhibited, while cell apoptosis was reversed by AKT inhibition. Conclusion: Selenium protected against homocysteine-induced dysfunction and apoptosis of endothelial cells through AKT pathway. The observations may provide novel therapeutic opportunities in the treatment of CVD.

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Cytotoxicity of Voriconazole on Cultured Human Corneal Endothelial Cells

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00569-11 ◽

2011 ◽

Vol 55 (10) ◽

pp. 4519-4523 ◽

Cited By ~ 30

Author(s):

Sang Beom Han ◽

Young Joo Shin ◽

Joon Young Hyon ◽

Won Ryang Wee

Keyword(s):

Endothelial Cells ◽

Cell Viability ◽

Toxic Effect ◽

Cell Damage ◽

Morphological Characteristics ◽

Cell Counting ◽

Dependent Manner ◽

Corneal Endothelial Cells ◽

Human Corneal Endothelial Cells ◽

Dose Dependent

ABSTRACTThe purpose of the present study was to evaluate the toxicity of voriconazole on cultured human corneal endothelial cells (HCECs). HCECs were cultured and exposed to various concentrations of voriconazole (5.0 to 1,000 μg/ml). Cell viability was measured using a Cell Counting Kit-8 (CCK-8) and live/dead viability/cytotoxicity assays. Cell damage was assessed using phase-contrast microscopy after 24 h of exposure to voriconazole. To analyze the effect of voriconazole on the intercellular barrier, immunolocalization of zonula occludens 1 (ZO1) was performed. A flow cytometric assay was performed to evaluate the apoptotic and necrotic effects of voriconazole on HCECs. Cytotoxicity tests demonstrated the dose-dependent toxic effect of voriconazole on HCECs. Voriconazole concentrations of ≥100 μg/ml led to a significant reduction in cell viability. The morphological characteristics of HCECs also changed in a dose-dependent manner. Increasing concentrations of voriconazole resulted in fading staining for ZO1. Higher concentrations of voriconazole resulted in an increased number of propidium iodide (PI)-positive cells, indicating activation of the proapoptotic pathway. In conclusion, voriconazole may have a dose-dependent toxic effect on cultured HCECs. The results of this study suggest that although voriconazole concentrations of up to 50 μg/ml do not decrease cell viability, intracameral voriconazole concentrations of ≥100 μg/ml may increase the risk of corneal endothelial damage.

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Endoplasmic reticulum stress regulates cell injury in lipopolysaccharide-induced nerve cells

Journal of International Medical Research ◽

10.1177/0300060520949762 ◽

2020 ◽

Vol 48 (9) ◽

pp. 030006052094976

Author(s):

Min Li ◽

Ying Zhang ◽

Jixing Wang

Keyword(s):

Endoplasmic Reticulum ◽

Cell Viability ◽

Er Stress ◽

Cell Apoptosis ◽

Caspase 3 ◽

Cell Injury ◽

Cell Counting ◽

Tunel Staining ◽

Dependent Manner ◽

Stress Markers

Objective Sepsis-associated encephalopathy (SAE) is a common complication of sepsis, and excessive endoplasmic reticulum (ER) stress is closely correlated with the cell injury caused by sepsis. This study aimed to analyze the possible role of ER stress in SAE cell models. Methods PC12 and MES23.5 cells were treated with increasing concentrations of lipopolysaccharides (LPS). The Cell Counting Kit-8 assay was used to detect cell viability and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was performed to assess cell apoptosis. In addition, the protein expression levels of ER stress markers [GRP78, CHOP, inositol-requiring enzyme 1 (IRE1), and PKR-like ER kinase (PERK)] and apoptosis-related proteins (Bax, Bcl-2, caspase-3, and cleaved caspase-3) were analyzed using western blotting. Results LPS treatment activated ER stress markers in both the PC12 and MES23.5 cells. The overexpression of GRP78 significantly reduced cell viability and enhanced cell apoptosis in a time-dependent manner. An ER stress inhibitor, 4-PBA, significantly enhanced cell viability and inhibited the cell apoptosis induced by LPS. Therefore, an enhanced unfolded protein response (UPR) and UPR suppression may regulate cell apoptosis. Conclusions UPR was shown to be involved in regulating LPS-induced neuron injury. UPR could be a potential therapeutic target in SAE.

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Treatment With G-CSF Reduces Acute Myeloid Leukemia (AML) Blasts Viability In Presence Of Bone Marrow Stroma

Blood ◽

10.1182/blood.v122.21.1422.1422 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1422-1422

Author(s):

Meritxell Nomdedeu ◽

Marta Pratcorona ◽

Marina Díaz-Beyá ◽

Xavier Calvo ◽

Mari Carmen Lara-Castillo ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Cell Viability ◽

Clinical Benefit ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Leukemic Cells ◽

Cell Counting ◽

Dependent Manner ◽

Dose Dependent ◽

Acute Myeloid

Abstract Background The simultaneous administration of G-CSF and chemotherapy as a priming strategy has resulted in a clinical benefit in determined subsets of patients diagnosed with acute myeloid leukemia (AML) (Löwenberg et al, NEJM 2003; Pabst T, et al, Blood 2012). However, the mechanism responsible for this anti-leukemic effect is not fully characterized. We hypothesize that the clinical benefit may occur at least partially by the effect of G-CSF on leukemic stem cells (LSC). Objective The main goal of this project was to determine the effect of G-CSF on primary AML samples in vitro, especially on LSCs. Methods and patients Peripheral blood mononuclear cells (PBMC) from 10 AML patients were treated with G-CSF at increasing doses, alone or in co-culture with HS-5 stroma cells. Cell viability (7-AAD -eBioscience- cell death exclusion and volumetric cell counting) and surface phenotype was determined by flow cytometry (FACSVerse, BD) 72 hours after treatment. Data were analyzed using the FlowJo (Trastar) software. For clonogenicity assays, AML primary samples were treated for 18 hours with G-CSF at increasing concentrations and cultured in H4034 Optimum MethoCult (StemCell Technologies) for 14 days. Colonies were counted based on cellularity and morphology criteria. Results G-CSF treatment showed no effect on cell viability of the bulk leukemic population or on the CD34 + immature subpopulation. A dose-dependent increase in CXCR4 surface expression was observed, reaching a 1.4-fold of change at the highest concentration of G-CSF (100 μg/mL). In contrast, treatment of leukemia cells with G-CSF in the presence of stroma cells reduced the overall cell viability. Thus, a 32% decrease of cell viability was measured at the highest concentration used (p = 0.0006), while no significant changes in the frequency of each leukemic subpopulations were observed. Clonogenic capacity was significantly reduced in a dose-dependent manner upon treatment with G-CSF, achieving a 41% reduction at the highest G-CSF concentration (100 μg/mL). Conclusions G-CSF reduces the viability of leukemic cells when these cells are in co-culture with the HS-5 stroma cell line, suggesting that the presence of stroma cells is required for the cytotoxical effect of G-CSF on the blast population. Interestingly, G-CSF treatment decreased the clonogenic capacity of AML samples, therefore suggesting that G-CSF exerts its effect at least partially on LSCs. Our findings support the design of studies to explore new strategies of chemotherapy priming in AML patients. Disclosures: No relevant conflicts of interest to declare.

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Tetramethylpyrazine protects Schwann cells from ischemia-like injury and increases cell survival in cold ischemic rat nerves

Brazilian Journal of Pharmaceutical Sciences ◽

10.1590/s1984-82502015000100014 ◽

2015 ◽

Vol 51 (1) ◽

pp. 127-141

Author(s):

Ming-Ming Yang ◽

Wei Huang ◽

Dian-Ming Jiang

Keyword(s):

Cell Viability ◽

Cell Survival ◽

Schwann Cells ◽

Caspase 3 ◽

Chinese Herb ◽

Dependent Manner ◽

Protective Effects ◽

Injury Model ◽

Nerve Model ◽

Dose Dependent

Tetramethylpyrazine (TMP), a major active ingredient of Ligusticum wallichi Franchat extract (a Chinese herb), exhibits neuroprotective properties in ischemia. In this study, we assessed its protective effects on Schwann cells (SCs) by culturing them in the presence of oxygen glucose deprivation (OGD) conditions and measuring cell survival in cold ischemic rat nerves. In the OGD-induced ischemic injury model of SCs, we demonstrated that TMP treatment not only reduced OGD-induced cell viability losses, cell death, and apoptosis of SCs in a dose-dependent manner, and inhibited LDH release, but also suppressed OGD-induced downregulation of Bcl-2 and upregulation of Bax and caspase-3, as well as inhibited the consequent activation of caspase-3. In the cold ischemic nerve model, we found that prolonged cold ischemic exposure for four weeks was markedly associated with the absence of SCs, a decrease in cell viability, and apoptosis in preserved nerve segments incubated in University of Wisconsin solution (UWS) alone. However, TMP attenuated nerve segment damage by preserving SCs and antagonizing the decrease in nerve fiber viability and increase in TUNEL-positive cells in a dose-dependent manner. Collectively, our results indicate that TMP not only provides protective effects in an ischemia-like injury model of cultured rat SCs by regulating Bcl-2, Bax, and caspase-3, but also increases cell survival and suppresses apoptosis in the cold ischemic nerve model after prolonged ischemic exposure for four weeks. Therefore, TMP may be a novel and effective therapeutic strategy for preventing peripheral nervous system ischemic diseases and improving peripheral nerve storage.

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NDRG1 Targets TAF15 to Promote Endothelial Dysfunction and Hypoxia-Induced Pulmonary Hypertension

10.21203/rs.3.rs-794105/v1 ◽

2021 ◽

Author(s):

Chengwei Li ◽

Liang Dong ◽

Ning Zhu ◽

Xiujuan Zhang ◽

Ruzetuoheti Yiminniyaze ◽

...

Keyword(s):

Endothelial Cells ◽

Pulmonary Hypertension ◽

Endothelial Dysfunction ◽

Vascular Remodeling ◽

Tube Formation ◽

Cell Counting ◽

Dependent Manner ◽

Rat Models ◽

Chain Reactions

Abstract Background: The mechanism underlying vascular remodeling of hypoxia-induced pulmonary hypertension (HPH) is not fully elucidated. We hypothesized that hypoxia promotes expression of N-myc downstream regulated gene-1 (NDRG1) in human pulmonary arterial endothelial cells (HPAECs), which in turn leads to endothelial dysfunction and contributing to HPH. Methods: Lung samples were obtained from qualified patients and HPH rat models. Quantitative polymerase chain reactions, western blotting and immunohistochemistry were used to measure the expression of NDRG1. EdU incorporation assays, cell counting kit-8 (CCK-8) assays, transwell migration assays, and matrigel assays were conducted to detect the role of NDRG1 in HPACE function in vitro. HPH models were established in SD rats and were treated with plasmids expressing short hairpin RNAs (shRNAs) to silence NDRG1. The candidate binding partner(s) of NDRG1 was screened and validated via co-immunoprecipitation and immunofluorescence staining. Results: NDRG1 is up-regulated by hypoxia in a time-dependent manner in HPAECs. Expression of NDRG1 was increased in lung tissues of HPH patient and rat model. In vitro, silencing NDRG1 attenuated proliferation, migration and tube formation of HPAECs under hypoxia, while NDRG1 over-expression promoted these behaviors of HPAECs in normoxia. NDRG1 knock-down alleviated vascular remodeling and right ventricular hypertrophy in rat models of HPH. NDRG1 can directly interact with TATA-box binding protein associated factor 15 (TAF15) and promote its nuclear localization. Bioinformatics study found that Notch1 signaling was downstream of TAF15 in endothelial cells. TAF15 can promote HPAECs dysfunction via binding to Notch1 promoter region and subsequently increasing Notch1 expression. Conclusions: Taken together, hypoxia-induced up-regulation of NDRG1 contributes to endothelial dysfunction and HPH development through TAF15 upregulation of Notch1, suggesting the applicability of targeting NDRG1 in clinical treatment of HPH.

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Cigarette Smoke Extract and Lipopolysaccharides Induce Pyroptosis in Rats Pulmonary Microvascular Endothelial Cells

10.21203/rs.3.rs-1203341/v1 ◽

2022 ◽

Author(s):

Qizhi Wang ◽

Min Liu ◽

Yu Liu ◽

Zhen Zhang ◽

Zhengping Bai

Keyword(s):

Flow Cytometry ◽

Endothelial Cells ◽

Cell Viability ◽

Cigarette Smoke ◽

Cigarette Smoke Extract ◽

Microvascular Endothelial Cells ◽

Dependent Manner ◽

Pulmonary Microvascular Endothelial Cells ◽

Microvascular Endothelial ◽

Dose Dependent

Abstract Objective: To investigate the effects of cigarette smoke extract (CSE) and lipopolysaccharide (LPS) on the activity and pyroptosis of pulmonary microvascular endothelial cells (PMVECs). Methods: PMVECs were cultured without treatment or with CSE (1%-25%), LPS, or CSE+LPS. Cell viability was detected using the CCK8 method. Apoptosis was evaluated by flow cytometry. Cell morphology was evaluated using optical microscopy. The content of IL-1β and IL-18 was measured by ELISA. Results: CSE decreased cell viability in a dose-dependent manner. The cells in the CSE+LPS group showed the most obvious cytomorphological changes and the highest pyroptosis rate under the microscope. Flow cytometry showed that the CSE and LPS groups showed higher apoptosis rates than the blank group; the apoptotic rate in the CSE+LPS group was even higher (P<0.01). Compared with the bkank group, the levels of IL-18 and IL-1β in the cell supernatant of the CSE, LPS, and CSE+LPS groups increased significantly, with significant differences (P<0.01). There were no differences between the CSE and LPS groups (P>0.05). Compared with the CSE and LPS groups, the CSE+LPS group had higher IL-18 and IL-1β (P<0.01). Conclusion: The effect of CSE on cell viability is dose-dependent. CSE+LPS can induce cell pyroptosis and increase the levels of inflammatory cytokines in PMVECs. These observations demonstrated that pyroptosis caused by CSE and LPS might play an important role in pulmonary vascular remodeling.

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Decrease of tetrahydrobiopterin and NO generation in endothelial cells exposed to simulated diving

Undersea and Hyperbaric Medicine ◽

10.22462/04.06.2019.9 ◽

2019 ◽

pp. 159-169

Author(s):

Ronja Hesthammer ◽

◽

Torunn Eide ◽

Eimar Thorsen ◽

Asbjørn M. Svardal ◽

...

Keyword(s):

Endothelial Cells ◽

Decompression Sickness ◽

Synergistic Effects ◽

Umbilical Vein ◽

Bubble Formation ◽

No Production ◽

Dependent Manner ◽

Hyperoxic Exposure ◽

Umbilical Vein Endothelial Cells ◽

Dose Dependent

Purpose: Nitric oxide (NO) has been shown to protect against bubble formation and the risk of decompression sickness. We hypothesize that oxidation of tetrahydrobiopterin (BH4) leads to a decreased production of NO during simulated diving. Methods: Human umbilical vein endothelial cells (HUVEC) were exposed to hyperoxia or simulated diving for 24 hours. The levels of biopterins (BH4, BH2 and B) were determined by LC-MS/MS, and the production of NO by monitoring the conversion of L-arginine to L-citrulline. Results: Exposure to hyperoxia decreased BH4 in a dose-dependent manner; by 48 ± 15% following exposure to 40 kPa O2 (P < 0.001 vs. control at 20 kPa O2), and 70 ± 16% following exposure to 60 kPa O2. Exposure to 40 kPa O2 decreased NO production by 25 ± 9%, but there was no further decrease when increasing oxygen exposure to 60 kPa (25 ± 10%). No additional effects of simulated diving were observed, indicating no additive or synergistic effects of hyperbaria and hyperoxia on the BH4 level or NO generation. Conclusion: NO generation in intact human endothelial cells was decreased by simulated diving, as well as by hyperoxic exposure, while BH4 levels seem to be affected only by hyperoxia. Hence, the results suggest that BH4 is not the sole determinant of NO generation in HUVEC.

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Nitric Oxide is Produced by Cowdria ruminantium-Infected Bovine Pulmonary Endothelial Cells In Vitro and Is Stimulated by Gamma Interferon

Infection and Immunity ◽

10.1128/iai.66.5.2115-2121.1998 ◽

1998 ◽

Vol 66 (5) ◽

pp. 2115-2121 ◽

Cited By ~ 16

Author(s):

Mbithe Mutunga ◽

Patricia M. Preston ◽

Keith J. Sumption

Keyword(s):

Nitric Oxide ◽

Endothelial Cells ◽

No Synthase ◽

No Production ◽

Dependent Manner ◽

Donor Molecule ◽

No Donor ◽

Pulmonary Endothelial Cells ◽

Cowdria Ruminantium ◽

Dose Dependent

ABSTRACT Nitric oxide (NO) is a labile inorganic free radical produced by NO synthase from the substrate l-arginine in various cells and tissues including endothelial cells. A substantial elevation of nitrite levels indicative of NO production occurred in cultures ofCowdria ruminantium-infected bovine pulmonary endothelial cells (BPEC) incubated in medium alone. Exposure of the infected cultures to recombinant bovine gamma interferon (BorIFN-γ) resulted in more rapid production of NO, reduced viability of C. ruminantium, and induction of endothelial cell death. Significant inhibition of NO production was noted after addition of the NO synthase inhibitor N-monomethyl-l-arginine (l-NMMA), indicating that the increase in production occurred via the inducible NO synthase pathway. Reduction in the infectivity of C. ruminantium elementary bodies (EBs) occurred in a dose-dependent manner after incubation with the NO donor moleculeS-nitroso-N-acetyl-dl-penicillamine (SNAP) prior to infection of endothelial cells. The level of infection in cultures maintained in SNAP was reduced in a dose-dependent manner with significant negative correlation between the final level of infection on day 7 and the level of SNAP (r = −0.96). It was established that pretreatment and cultivation of C. ruminantium EBs with the NO donor molecule SNAP reduced infectivity to cultures and viability of EBs with the implication that release of NO in vivo following infection of endothelial cells may have an effect upon the multiplication of the agent in the host animal and may be involved in the pathogenesis of heartwater through the effect of this molecule upon circulation.

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Daratumumab Directly Induces Human Multiple Myeloma Cell Death and Acts Synergistically with Conventional and Novel Anti-Myeloma Drugs

Blood ◽

10.1182/blood.v116.21.3013.3013 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3013-3013

Author(s):

Sun-Young Kong ◽

Xian-Feng Li ◽

Sabikun Nahar ◽

Weihua Song ◽

Michel de Weers ◽

...

Keyword(s):

Multiple Myeloma ◽

Cell Death ◽

Cell Viability ◽

Caspase 3 ◽

Annexin V ◽

Dependent Manner ◽

Cell Viability Assay ◽

Viability Assay ◽

Synergistic Cytotoxicity ◽

Dose Dependent

Abstract Abstract 3013 Daratumumab is a novel fully human therapeutic CD38-specific monoclonal antibody (mAb) that is currently in phase I/II safety and dose finding clinical studies in MM. We recently demonstrated that daratumumab induces antibody dependent cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC) against multiple myeloma (MM) cells (ASH Abstract #608, 2009). Significantly, daratumumab induces ADCC-mediated autologous lysis against MM patient cells. In addition, when cross-linked, daratumumab directly induces Ramos lymphoma cell death. We here studied whether daratumumab directly kills MM cells and whether daratumumab could be combined with other anti-MM drugs to further enhance its direct cytotoxicity. Direct daratumumab-induced MM cell death was determined using CellTiter-Glo luminescent cell viability assay and Annexin V/PI flow cytometry analysis, with or without goat anti-human IgG crosslinking. Following 48h incubation, daratumumab (0.1-10 μg/ml), when cross-linked, directly induced cytoxicity against dexamethasone (dex)-sensitive MM1S and dex-resistant MM1R cells, as evidenced by decreased cell viability in a dose-dependent manner. Importantly, cross-linked daratumumab increased caspase 3/7 activities in a dose-dependent fashion, as assessed by the Caspase-Glo® 3/7 luminescence assay. Furthermore, daratumumab upregulated Annexin V+ and Annexin V+/PI+ cells in freshly isolated CD138+ MM patient cells, from 7.7% to 20.6% and 10.9% to 15.4 %. Therefore, cross-linked daratumumab can directly trigger apoptosis of patient myeloma cells. Cell viability assay was further performed on MM1S cells when daratumumab (0.1, 1, 10 μg/ml) was combined with dex (0.5 and 1 μM) or bortezomib (2.5, 5, and 10 nM). Following 48–72h incubation with daratumumab, both dex and bortezomib synergistically inhibited MM cell viability, as determined by combination index (CI) < 0.5 at given combined concentrations of these drugs. Enhanced caspase 3/7 activation was also seen when daratumumab was combined with dex. To evaluate combination cytotoxicity induced by lenalidomide with daratumumab, peripheral blood mononuclear effector cells (PBMCs) from normal donors (n=2) were pretreated with lenalidomide (2 μM) for 3 days followed by daratumumab-mediated ADCC assays against MM1S cells. Using calcein-AM release measurements, lenalidomide-pretreated PBMCs further augmented daratumumab-induced MM1S cell lysis, whereas daratumumab-pretreated PBMCs did not alter ADCC. Taken together, our studies show that daratumumab directly induces MM cell death via activation of caspase 3/7 and daratumumab induced synergistic cytotoxicity with dex or bortezomib. Moreover, lenalidomide augments daratumumab-induced ADCC against MM cells. These results further support combination clinical trials of conventional and novel anti-MM drugs with daratumumab in MM. Disclosures: Weers: Genmab: Employment. Parren:Genmab: Employment. Richardson:Keryx Biopharmaceuticals: Honoraria. Munshi:Millennium Pharmaceuticals: Honoraria, Speakers Bureau. Anderson:Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

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Activated pericyte attenuates endothelial functions: nitric oxide – cGMP rescues activated pericyte-associated endothelial dysfunctions

Biochemistry and Cell Biology ◽

10.1139/o07-140 ◽

2007 ◽

Vol 85 (6) ◽

pp. 709-720 ◽

Cited By ~ 5

Author(s):

Syamantak Majumder ◽

K. P. Tamilarasan ◽

Gopi Krishna Kolluru ◽

Ajit Muley ◽

C. Madhavan Nair ◽

...

Keyword(s):

Nitric Oxide ◽

Endothelial Cells ◽

Endothelial Dysfunction ◽

Phosphodiesterase Inhibitor ◽

Egg Yolk ◽

No Production ◽

Dependent Manner ◽

Endothelium Dysfunction ◽

Vascular Bed

Hepatic stellate cells are liver-specific pericytes and exist in close proximity with endothelial cells. The activation of liver pericytes is intrinsic to liver pathogenesis, and leads to endothelial dysfunction, including the low bioavailability of nitric oxide (NO). However, the role of nitric oxide in pericyte–endothelium cross-talk has not yet been elucidated. This work examines the cellular mechanism of action of NO in pericyte-mediated endothelial dysfunction. We used in vitro coculture and conditioned medium systems to study the effects of activated liver pericytes on endothelial function, and an egg yolk vascular bed model was used to study the effects of activated pericytes on angiogenesis. This study also demonstrates that activated pericytes attenuate the migration, proliferation, permeability, and NO production of endothelial cells. Our results demonstrate that activated pericytes restrict angiogenesis in egg yolk vascular bed models, and NO supplementation recovers 70% of the inhibition. Our results also demonstrate that supplementation with NO, sildenafil citrate (phosphodiesterase inhibitor), and 8-bromo-cGMP (cGMP analog) partially recovers activated-pericyte-mediated endothelium dysfunction. We conclude that NO–cGMP alleviates activated-pericyte-associated endothelial dysfunction, including angiogenesis, in a cGMP-dependent manner.

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