scholarly journals NADPH Oxidase 4-Derived H2O2Promotes Aberrant Retinal Neovascularization via Activation of VEGF Receptor 2 Pathway in Oxygen-Induced Retinopathy

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Jingming Li ◽  
Joshua J. Wang ◽  
Sarah X. Zhang
Keyword(s):  
Endothelial Cells ◽  
Nadph Oxidase ◽  
Tube Formation ◽  
Retinal Neovascularization ◽  
Mouse Retina ◽  
Vegf Receptor ◽  
Retinal Endothelial Cells ◽  
Oxygen Induced Retinopathy ◽  
Nadph Oxidase 4 ◽  
Promising Therapeutic Approach

NADPH oxidase 4 (Nox4) is a major isoform of NADPH oxidase in retinal endothelial cells. Our previous study suggests that upregulation of Nox4 in retinal endothelial cells contributes to retinal vascular leakage in diabetes. In the current study, we investigated the role and mechanism of Nox4 in regulation of retinal neovascularization (NV), a hallmark of proliferative diabetic retinopathy (PDR), using a mouse model of oxygen-induced retinopathy (OIR). Our results confirmed that Nox4 was expressed predominantly in retinal vasculature of mouse retina. Retinal expression of Nox4 was markedly increased in OIR, in parallel with enhanced phosphorylation of ERK. In human retinal microvascular endothelial cells (HRECs), overexpression of Nox4 by adenovirus significantly increased extracellular H2O2generation, resulting in intensified VEGFR2 activation and exacerbated angiogenesis upon VEGF stimulation. In contrast, silencing Nox4 expression or scavenging H2O2by polyethylene glycol- (PEG-) conjugated catalase inhibited endothelial migration, tube formation, and VEGF-induced activation of VEGFR2 signaling. Importantly, knockdown of retinal Nox4 by adenovirus-delivered siRNA significantly reduced ERK activation and attenuated retinal NV formation in OIR. Taken together, our data indicate that Nox4 promotes retinal NV formation through H2O2/VEGFR2/ERK signaling pathway. Reducing retinal Nox4 expression may represent a promising therapeutic approach for neovascular retinal diseases such as PDR.

scholarly journals Aster koraiensis Extract and Chlorogenic Acid Inhibit Retinal Angiogenesis in a Mouse Model of Oxygen-Induced Retinopathy

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Junghyun Kim ◽  
Yun Mi Lee ◽  
Wookwon Jung ◽  
Su-Bin Park ◽  
Chan-Sik Kim ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Mouse Model ◽  
Chlorogenic Acid ◽  
Vascular Endothelial Cells ◽  
Tube Formation ◽  
Retinal Neovascularization ◽  
Age Related Macular Degeneration ◽  
Dependent Manner ◽  
Vascular Endothelial ◽  
Oxygen Induced Retinopathy

Aster koraiensis extract (AKE) is a standard dietary herbal supplement. Chlorogenic acid (CA) is the major compound present in AKE. Retinal neovascularization is a common pathophysiology of retinopathy of prematurity, diabetic retinopathy, and wet form age-related macular degeneration. In this study, we aimed to evaluate the effects of AKE and CA on retinal neovascularization in a mouse model of oxygen-induced retinopathy (OIR). Vascular endothelial growth factor- (VEGF-) induced tube formation was assayed in human vascular endothelial cells. Experimental retinal neovascularization was induced by exposing C57BL/6 mice to 75% oxygen on postnatal day 7 (P7) and then returning them to normal oxygen pressure on P12. AKE (25 and 50 mg/kg/day) and CA (25 and 50 mg/kg/day) were administered intraperitoneally for 5 days (P12–P16). Retinal flat mounts were prepared to measure the extent of retinal neovascularization at P17. The incubation of human vascular endothelial cells with AKE and CA (1–10 μg/mL) resulted in the inhibition of VEGF-mediated tube formation in a dose-dependent manner. The neovascular area was significantly smaller in AKE or CA-treated mice than in the vehicle-treated mice. These results suggest that AKE is a potent antiangiogenic agent and that its antiangiogenic activity may, in part, be attributable to the bioactive component CA.

scholarly journals Adenosine triphosphate is a critical determinant for VEGFR signal during hypoxia

2016 ◽  
Vol 311 (6) ◽  
pp. C985-C995 ◽  
Author(s):  
Abdullah Al Mamun ◽  
Hisaki Hayashi ◽  
Miho Sakima ◽  
Motohiko Sato
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Signal Propagation ◽  
Tube Formation ◽  
Activation Process ◽  
Vegf Receptor ◽  
Vegf Mrna ◽  
Critical Determinant ◽  
Hypoxia Exposure ◽  
Vegf Signaling

Hypoxia induces angiogenesis through the VEGF signaling pathway; however, signal propagation of VEGF in hypoxia is not fully understood. In this study, we examined alterations in VEGF signaling during hypoxia conditions and its determinant in endothelial cells. To analyze VEGF signaling during hypoxia, human umbilical vein endothelial cells (HUVECs) were exposed to 3 h of hypoxia (1% O2) followed by 3 h of reoxygenation or 12 h of hypoxia. Hypoxia induced expression of VEGF mRNA, but it was not associated with an increase in tube formation by HUVECs. During 3 h of hypoxia, VEGF-induced phosphorylation of VEGF receptor-2 (VEGFR-2) and downstream molecules were significantly inhibited without a change in VEGFR-2 expression, but it was completely restored after reoxygenation. VEGF-mediated VEGFR-2 phosphorylation is associated with a reduction in cellular ATP in hypoxia conditions (65.93 ± 8.32% of normoxia, means ± SE, P < 0.01). Interestingly, attenuation of VEGFR-2 phosphorylation was restored by addition of ATP to prepared membranes from cells that underwent 3 h of hypoxia. In contrast to 3 h of hypoxia, exposure of cells to 12 h of hypoxia decreased VEGFR-2 expression and VEGF-mediated VEGFR-2 phosphorylation. The magnitude of VEGFR-2 phosphorylation was not fully restored by addition of ATP to prepared membranes from cells exposed to 12 h of hypoxia. These data indicate that ATP is an important determinant of VEGF signaling in hypoxia and suggest that the activation process of VEGFR-2 was modified by sustained hypoxia. These observations contribute to our understanding of signal alterations in VEGF in endothelial cells during hypoxia.

Degradation of soluble VEGF receptor-1 by MMP-7 allows VEGF access to endothelial cells

Blood ◽  
2009 ◽  
Vol 113 (10) ◽  
pp. 2363-2369 ◽  
Author(s):  
Ta-Kashi Ito ◽  
Genichiro Ishii ◽  
Seiji Saito ◽  
Keiichi Yano ◽  
Ayuko Hoshino ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Critical Role ◽  
Inhibitory Effect ◽  
Tube Formation ◽  
Membrane Receptors ◽  
Vegf Receptor ◽  
Migration Assay ◽  
Vegf Inhibitor ◽  
Umbilical Vein Endothelial Cells

AbstractVascular endothelial growth factor (VEGF) signaling in endothelial cells serves a critical role in physiologic and pathologic angiogenesis. Endothelial cells secrete soluble VEGF receptor-1 (sVEGFR-1/sFlt-1), an endogenous VEGF inhibitor that sequesters VEGF and blocks its access to VEGF receptors. This raises the question of how VEGF passes through this endogenous VEGF trap to reach its membrane receptors on endothelial cells, a step required for VEGF-driven angiogenesis. Here, we show that matrix metalloproteinase-7 (MMP-7) degrades human sVEGFR-1, which increases VEGF bioavailability around the endothelial cells. Using a tube formation assay, migration assay, and coimmunoprecipitation assay with human umbilical vein endothelial cells (HUVECs), we show that the degradation of sVEGFR-1 by MMP-7 liberates the VEGF165 isoform from sVEGFR-1. The presence of MMP-7 abrogates the inhibitory effect of sVEGFR-1 on VEGF-induced phosphorylation of VEGF receptor-2 on HUVECs. These data suggest that VEGF escapes the sequestration by endothelial sVEGFR-1 and promotes angiogenesis in the presence of MMP-7.

scholarly journals Inhibiting the NLRP3 inflammasome with MCC950 ameliorates retinal neovascularization and leakage by reversing the IL-1β/IL-18 activation pattern in an oxygen-induced ischemic retinopathy mouse model

2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Ailing Sui ◽  
Xiuping Chen ◽  
Jikui Shen ◽  
Anna M. Demetriades ◽  
Yiyun Yao ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Growth Factor ◽  
Nlrp3 Inflammasome ◽  
Retinal Neovascularization ◽  
Platelet Derived Growth Factor ◽  
Vegf Receptor ◽  
Activation Pattern ◽  
Ischemic Retinopathy

Abstract Activation of the nucleotide-binding domain leucine-rich repeat and pyrin domain containing receptor 3 (NLRP3) inflammasome plays an important role in ocular neovascularization. In our study, we found that the expression and activation levels of NLRP3 inflammasome components, including NLRP3, an apoptosis-associated speck-like protein (ASC) containing caspase activation and recruitment domain (CARD) and caspase-1 (CAS1), were significantly upregulated. In addition, we found interleukin (IL)-1β activity increased while IL-18 activity decreased in the retinas of oxygen-induced ischemic retinopathy (OIR) mice. MCC950, an inhibitor of NLRP3, reversed the IL-1β/IL-18 activation pattern, inhibited the formation of retinal neovascularization (RNV), decreased the number of acellular capillaries and reduced leakage of retinal vessels. Moreover, MCC950 could regulate the expression of endothelial cell- and pericyte function-associated molecules, such as vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR)1, VEGFR2, matrix metalloproteinase (MMP)2, MMP9, tissue inhibitor of metalloproteinases (TIMP)1, TIMP2, platelet-derived growth factor receptor-β (PDGFR-β), platelet-derived growth factor-B (PDGF-B), and angiopoietin2 (Ang2). In vitro, recombinant human (r)IL-18 and rIL-1β regulated the expression of endothelial cell- and pericyte function-associated molecules and the proliferation and migration of endothelial cells and pericytes. We therefore determined that inhibiting the NLRP3 inflammasome with MCC950 can regulate the function of endothelial cells and pericytes by reversing the IL-1β/IL-18 activation pattern to ameliorate RNV and leakage; thereby opening new avenues to treat RNV-associated ocular diseases.

scholarly journals Angiotensin II-induced process of angiogenesis is mediated by spleen tyrosine kinase via VEGF receptor-1 phosphorylation

2011 ◽  
Vol 301 (3) ◽  
pp. H1043-H1055 ◽  
Author(s):  
Cuneyt K. Buharalioglu ◽  
Chi Young Song ◽  
Fariborz A. Yaghini ◽  
Hafiz U. B. Ghafoor ◽  
Mustafa Motiwala ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tyrosine Kinase ◽  
Egf Receptor ◽  
Umbilical Vein ◽  
Underlying Mechanism ◽  
Tube Formation ◽  
Vegf Receptor ◽  
Ang Ii ◽  
Spleen Tyrosine Kinase ◽  
Vegf Expression

Spleen tyrosine kinase (Syk), expressed in endothelial cells, has been implicated in migration and proliferation and in vasculogenesis. This study was conducted to determine the contribution of Syk and the underlying mechanism to the angiogenic effect of ANG II and VEGF. Angiogenesis was determined by tube formation from the endothelial cell line EA.hy926 (EA) and human umbilical vein endothelial cells (HUVECs) and microvessel sprouting in rat aortic rings. ANG II (10 nM), EGF (30 ng/ml), and VEGF (50 ng/ml) stimulated EA cells and HUVECs to form tubular networks and increased aortic sprouting; these effects were blocked by VEGF receptor-1 and Flt-1 antibody (Flt-1/Fc) but not by the VEGF receptor-2 (Flk-1) antagonist SU-1498. ANG II increased the phosphorylation of Flt-1 but not Flk-1, whereas VEGF increased the phosphorylation of both receptors in EA cells and HUVECs. VEGF expression elicited by ANG II was not altered by Flt-1/Fc or SU-1498. EGF stimulated tube formation from EA cells and HUVECs and Flt-1 phosphorylation and aortic sprouting, which were blocked by the EGF receptor antagonist AG-1478 and Flt-1/Fc but not by SU-1498. ANG II-, EGF-, and VEGF-induced tube formation and aortic sprouting were attenuated by the Syk inhibitor piceatannol and by Syk short hairpin interfering (sh)RNA and small interfering RNA, respectively. ANG II, EGF, and VEGF increased Syk phosphorylation, which was inhibited by piceatannol and Syk shRNA in EA cells and HUVECs. Neither piceatannol nor Syk shRNA altered ANG II-, EGF-, or VEGF-induced phosphorylation of Flt-1. These data suggest that ANG II stimulates angiogenesis via transactivation of the EGF receptor, which promotes the phosphorylation of Flt-1 and activation of Syk independent of VEGF expression.

scholarly journals Tim-3 promotes tube formation and decreases tight junction formation in vascular endothelial cells

2020 ◽  
Vol 40 (10) ◽  
Author(s):  
Yizi Cong ◽  
Xingmiao Wang ◽  
Suxia Wang ◽  
Guangdong Qiao ◽  
Yalun Li ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tight Junction ◽  
Immune Escape ◽  
Vascular Endothelial Cells ◽  
Tumour Progression ◽  
Umbilical Vein ◽  
Tube Formation ◽  
In Vitro Assays ◽  
Vegf Receptor ◽  
Vascular Endothelial

Abstract As a negative immune checkpoint molecule, T-cell immunoglobulin domain and mucin domain containing molecule-3 (Tim-3) has been found to serve a crucial role in immune escape and tumour progression. Previous studies have reported that Tim-3 is important to endothelial cells and it has also been demonstrated to be involved in numerous types of human diseases, including melanoma, lymphoma, rickettsial infection and atherosclerosis; however, its exact mechanism of action remains largely unknown. In the present study, Tim-3 was overexpressed in vascular endothelial human lung microvascular endothelial cells (HMVECs) and human umbilical vein endothelial cells (HUVECs), and in vitro assays were used to determine that Tim-3 promoted cell proliferation, migration, invasion and tube formation through activating cyclin D1 (CCND1), Ras homolog gene family member A and vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2). Additionally, Tim-3 decreased tight junction (TJ) formation and the transepithelial resistance (TER) of endothelial cells by decreasing the expression levels of TJ protein 2, Occludin and claudin 1 (CLND1). In conclusion, these findings suggested that Tim-3 may exert a positive role in angiogenesis and a negative role in TJ formation in vascular endothelial cells, which may provide novel strategies for the treatment of Tim-3-associated diseases.

NADPH oxidase 4 mediates upregulation of type 4 phosphodiesterases in human endothelial cells

2012 ◽  
Vol 227 (5) ◽  
pp. 1941-1950 ◽  
Author(s):  
Saima Muzaffar ◽  
Jamie Y. Jeremy ◽  
Gianni D. Angelini ◽  
Nilima Shukla
Keyword(s):  
Endothelial Cells ◽  
Nadph Oxidase ◽  
Human Endothelial Cells ◽  
Nadph Oxidase 4
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