scholarly journals Angiopoietin-1 Mimetic Nanoparticles for Restoring the Function of Endothelial Cells as Potential Therapeutic for Glaucoma

2021 ◽  
Vol 15 (1) ◽  
pp. 18
Author(s):  
Raphael Mietzner ◽  
Ramona Pawlak ◽  
Ernst R. Tamm ◽  
Achim Goepferich ◽  
Rudolf Fuchshofer ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cellular Response ◽  
Cell Function ◽  
Open Angle Glaucoma ◽  
Cell Interaction ◽  
Receptor Activation ◽  
Poly Lactic Acid ◽  
Ligand Density ◽  
Modified Polymer ◽  
Angiopoietin 1

A root cause for the development and progression of primary open-angle glaucoma might be the loss of the Schlemm’s canal (SC) cell function due to an impaired Angiopoietin-1 (Angpt-1)/Tie2 signaling. Current therapeutic options fail to restore the SC cell function. We propose Angpt-1 mimetic nanoparticles (NPs) that are intended to bind in a multivalent manner to the Tie2 receptor for successful receptor activation. To this end, an Angpt-1 mimetic peptide was coupled to a poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) block co-polymer. The modified polymer allowed for the fabrication of Angpt-1 mimetic NPs with a narrow size distribution (polydispersity index < 0.2) and the size of the NPs ranging from about 120 nm (100% ligand density) to about 100 nm (5% ligand density). NP interaction with endothelial cells (HUVECs, EA.hy926) as surrogate for SC cells and fibroblasts as control was investigated by flow cytometry and confocal microscopy. The NP–cell interaction strongly depended on the ligand density and size of NPs. The cellular response to the NPs was investigated by a Ca2+ mobilization assay as well as by a real-time RT-PCR and Western blot analysis of endothelial nitric oxide synthase (eNOS). NPs with a ligand density of 25% opposed VEGF-induced Ca2+ influx in HUVECs significantly which could possibly increase cell relaxation and thus aqueous humor drainage, whereas the expression and synthesis of eNOS was not significantly altered. Therefore, we suggest Angpt-1 mimetic NPs as a first step towards a causative therapy to recover the loss of SC cell function during glaucoma.

scholarly journals Angiopoietin-1 Knockout Mice as a Genetic Model of Open-Angle Glaucoma

2020 ◽  
Vol 9 (4) ◽  
pp. 16 ◽  
Author(s):  
Benjamin R. Thomson ◽  
Marta Grannonico ◽  
Feng Liu ◽  
Mingna Liu ◽  
Parrykumar Mendapara ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Genetic Model ◽  
Open Angle Glaucoma ◽  
Open Angle ◽  
Angiopoietin 1

scholarly journals Investigation of Wall Shear Stress in Cardiovascular Research and in Clinical Practice—From Bench to Bedside

2021 ◽  
Vol 22 (11) ◽  
pp. 5635
Author(s):  
Katharina Urschel ◽  
Miyuki Tauchi ◽  
Stephan Achenbach ◽  
Barbara Dietel
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Cell Function ◽  
Computational Techniques ◽  
Apical Surface ◽  
Cardiovascular Research ◽  
Endothelial Cell Function ◽  
Wall Shear

In the 1900s, researchers established animal models experimentally to induce atherosclerosis by feeding them with a cholesterol-rich diet. It is now accepted that high circulating cholesterol is one of the main causes of atherosclerosis; however, plaque localization cannot be explained solely by hyperlipidemia. A tremendous amount of studies has demonstrated that hemodynamic forces modify endothelial athero-susceptibility phenotypes. Endothelial cells possess mechanosensors on the apical surface to detect a blood stream-induced force on the vessel wall, known as “wall shear stress (WSS)”, and induce cellular and molecular responses. Investigations to elucidate the mechanisms of this process are on-going: on the one hand, hemodynamics in complex vessel systems have been described in detail, owing to the recent progress in imaging and computational techniques. On the other hand, investigations using unique in vitro chamber systems with various flow applications have enhanced the understanding of WSS-induced changes in endothelial cell function and the involvement of the glycocalyx, the apical surface layer of endothelial cells, in this process. In the clinical setting, attempts have been made to measure WSS and/or glycocalyx degradation non-invasively, for the purpose of their diagnostic utilization. An increasing body of evidence shows that WSS, as well as serum glycocalyx components, can serve as a predicting factor for atherosclerosis development and, most importantly, for the rupture of plaques in patients with high risk of coronary heart disease.

scholarly journals An autoantibody directed against human thrombin anion-binding exosite in a patient with arterial thrombosis: effects on platelets, endothelial cells, and protein C activation

Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1843-1850 ◽  
Author(s):  
E Arnaud ◽  
M Lafay ◽  
P Gaussem ◽  
V Picard ◽  
M Jandrot-Perrus ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Arterial Thrombosis ◽  
Protein C ◽  
Receptor Activation ◽  
Anion Binding ◽  
Thrombin Receptor ◽  
Cell Functions ◽  
Human Thrombin

Abstract An autoantibody, developed by a patient with severe and recurrent arterial thrombosis, was characterized to be directed against the anion- binding exosite of thrombin, and inhibited all thrombin interactions requiring this secondary binding site without interfering with the catalytic site. The effect of the antibody was studied on thrombin interactions with platelets and endothelial cells from human umbilical veins (HUVEC). The autoantibody specifically and concentration- dependently inhibited alpha-thrombin-induced platelet activation and prostacyclin (PGI2) synthesis from HUVEC. It had no effect when gamma- thrombin or the thrombin receptor activation peptide SFLLR were the inducers. The effect of the antibody on protein C activation has been studied. The antibody blocked the thrombin-thrombomodulin activation of protein C. The inhibition of the activation was maximal with a low concentration of thrombomodulin. The fact that the autoantibody inhibited concentration-dependent alpha-thrombin-induced platelet and endothelial cell functions emphasizes the crucial role of the anion- binding exosite of thrombin to activate its receptor. In regard to the pathology, the antibody inhibited two vascular processes implicated in thrombin-antithrombotic functions, PGI2 secretion, and protein C activation, which could be implicated in this arterial thrombotic disease.

Systemic Analysis of Tyrosine Phosphorylated Proteins in Angiopoietin-1 Induced Signaling Pathway of Endothelial Cells

2007 ◽  
Vol 6 (8) ◽  
pp. 3278-3290 ◽  
Author(s):  
Young Mee Kim ◽  
Jawon Seo ◽  
Yung Hee Kim ◽  
Jaeho Jeong ◽  
Hye Joon Joo ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Signaling Pathway ◽  
Phosphorylated Proteins ◽  
Systemic Analysis ◽  
Angiopoietin 1

Endothelial Cell-Immune Cell Interaction in IBD

2016 ◽  
Vol 34 (1-2) ◽  
pp. 43-50 ◽  
Author(s):  
Silvio Danese ◽  
Claudio Fiocchi
Keyword(s):  
Endothelial Cells ◽  
Immune Cells ◽  
Bowel Wall ◽  
Regulatory Mechanism ◽  
Immune Cell ◽  
Cell Interaction ◽  
Mesenteric Lymph Nodes ◽  
Mesenteric Lymph ◽  
Inflammatory Bowel ◽  
Lymphatic Fluid

The proper delivery of immune cells throughout the host's various tissues and organs is essential to health, and abnormalities in the type and quantity of leukocyte distribution is usually associated with disease. Because of its size and presence of a very large amount of immunocytes in the mucosa and mesenteric lymph nodes, the gut is the recipient of a constant influx of leukocytes, a process tightly regulated by multiple factors. These include cell adhesion molecules on the leukocytes and their counter-receptors on the microvascular endothelial cells in the bowel wall, a number of chemokines and cytokines that help attracting immune cells, platelets, bacterial products, danger signals, the size of the vascular and lymphatic beds and the process of leukocyte exit and circulation in the blood and lymphatic fluid. The disruption of any of the above regulatory mechanism can lead to inflammation, as is the case for inflammatory bowel disease. Learning how leukocyte and endothelial cells mutually function in health and what goes wrong in inflammation offers the opportunity to intervene therapeutically and re-establish the normal crosstalk between leukocytes and endothelial cells.

scholarly journals The binding of NCAM to FGFR1 induces a specific cellular response mediated by receptor trafficking

2009 ◽  
Vol 187 (7) ◽  
pp. 1101-1116 ◽  
Author(s):  
Chiara Francavilla ◽  
Paola Cattaneo ◽  
Vladimir Berezin ◽  
Elisabeth Bock ◽  
Diletta Ami ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cellular Response ◽  
Critical Role ◽  
Biological Significance ◽  
Receptor Activation ◽  
Dependent Manner ◽  
Fgf Receptor ◽  
Neural Cell Adhesion ◽  
Sustained Activation

Neural cell adhesion molecule (NCAM) associates with fibroblast growth factor (FGF) receptor-1 (FGFR1). However, the biological significance of this interaction remains largely elusive. In this study, we show that NCAM induces a specific, FGFR1-mediated cellular response that is remarkably different from that elicited by FGF-2. In contrast to FGF-induced degradation of endocytic FGFR1, NCAM promotes the stabilization of the receptor, which is recycled to the cell surface in a Rab11- and Src-dependent manner. In turn, FGFR1 recycling is required for NCAM-induced sustained activation of various effectors. Furthermore, NCAM, but not FGF-2, promotes cell migration, and this response depends on FGFR1 recycling and sustained Src activation. Our results implicate NCAM as a nonconventional ligand for FGFR1 that exerts a peculiar control on the intracellular trafficking of the receptor, resulting in a specific cellular response. Besides introducing a further level of complexity in the regulation of FGFR1 function, our findings highlight the link of FGFR recycling with sustained signaling and cell migration and the critical role of these events in dictating the cellular response evoked by receptor activation.

scholarly journals Protein C system defects inflicted by the malaria parasite protein PfEMP1 can be overcome by a soluble EPCR variant

2015 ◽  
Vol 114 (11) ◽  
pp. 1038-1048 ◽  
Author(s):  
Eveline A. M. Bouwens ◽  
Ibai Tamayo ◽  
Louise Turner ◽  
Christian W. Wang ◽  
Monique Stins ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Severe Malaria ◽  
Protein C ◽  
Cellular Response ◽  
Malaria Parasite ◽  
Vascular Endothelial Cells ◽  
Protective Effects ◽  
Endothelial Protein C Receptor ◽  
Parasite Protein ◽  
Soluble Epcr

SummaryThe Endothelial Protein C receptor (EPCR) is essential for the anticoagulant and cytoprotective functions of the Protein C (PC) system. Selected variants of the malaria parasite protein, Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) associated with severe malaria, including cerebral malaria, specifically target EPCR on vascular endothelial cells. Here, we examine the cellular response to PfEMP1 engagement to elucidate its role in malaria pathogenesis. Binding of the CIDRα1.1 domain of PfEMP1 to EPCR obstructed activated PC (APC) binding to EPCR and induced a loss of cellular EPCR functions. CIDRα1.1 severely impaired endothelial PC activation and effectively blocked APC-mediated activation of protease-activated receptor-1 (PAR1) and associated barrier protective effects of APC on endothelial cells. A soluble EPCR variant (E86A-sEPCR) bound CIDRα1.1 with high affinity and did not interfere with (A)PC binding to cellular EPCR. E86A-sEPCR used as a decoy to capture PfEMP1, permitted normal PC activation on endothelial cells, normal barrier protective effects of APC, and greatly reduced cytoadhesion of infected erythrocytes to brain endothelial cells. These data imply important contributions of PfEMP1-induced protein C pathway defects in the pathogenesis of severe malaria. Furthermore, the E86A-sEPCR decoy provides a proof-of-principle strategy for the development of novel adjunct therapies for severe malaria.

Abstract 1746: Insulin Like Growth Factor Binding Protein-3 (IGFBP-3) Mediates Vascular Repair By HDL Receptor Activation And Sphingosine Kinase (SK-1)/Sphingosine 1-Phosphate (S1P) Dependent Nitric Oxide (NO) Generation

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Sergio Li Calzi ◽  
Jennifer L Kielczewski ◽  
Evan McFarland ◽  
Kyung Hee Chang ◽  
Aqeela Afzal ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Scavenger Receptor ◽  
Receptor Activation ◽  
Hematopoietic Stem ◽  
Beneficial Effects ◽  
Sphingosine 1 Phosphate ◽  
Active Motor ◽  
Umbilical Vein Endothelial Cells ◽  
Igfbp 3

Purpose: We demonstrated that IGFBP-3 stimulates hematopoietic stem cells (HSC) to differentiate into endothelial cells, form capillaries, and stabilize the vasculature (Chang, et al, PNAS 2007). Local IGFBP- 3 production is increased by hypoxia and facilitates the homing of HSC to areas of injury. In the circulation, IGFBP-3 is bound to HDL. In this study, we investigated the signaling pathways responsible for the robust migratory effects of IGFBP-3. Methods: The effects of IGFBP-3 on NO generation in human vascular precursors (CD 34 + , CD14 − ), human lung microvascular endothelial cells, and human umbilical vein endothelial cells were examined using DAF-FM fluorescence. Western analysis was use for detection of eNOS and vasodilator-stimulated phosphoprotein (VASP), which redistributes to lamellipodia forming an active motor complex that supports motility and is phosphorylated in response to NO. Localization of VASP was performed by immunohistochemistry. SK-1 was assessed following IGFBP-3 stimulation. Results: In CD34 + cells and endothelial cells, IGFBP-3 stimulated eNOS phosphorylation at Ser1177 (102 ± 1.8%, P = 0.0002) and increased NO generation (275 ± 50%, P = 0.05) by increasing SK-1 and S1P generation. IGFBP-3 was bound and internalized by the HDL receptor, scavenger receptor 1B (SR1B). NO generation following IGFBP-3 exposure was reduced by SK inhibitors or SR-1B blocking antibody pretreatment (35 ± 5%, P < 0.02). IGFBP-3 generated NO increased phosphorylation of VASP at Ser239 and promoted the redistribution of VASP to lamellipodia. Conclusions: IGFBP-3 effects on cell migration are NO dependent and mediated in part by activation of the HDL receptor SR1B suggesting that some of the beneficial effects of HDL are mediated by the association of IGFBP-3.

Micropatterned array to assess the interaction of single platelets with platelet factor 4-heparin-IgG complexes

2014 ◽  
Vol 111 (05) ◽  
pp. 862-872 ◽  
Author(s):  
Krystin Krauel ◽  
Nikolay Medvedev ◽  
Raghavendra Palankar ◽  
Andreas Greinacher ◽  
Mihaela Delcea
Keyword(s):  
Calcium Imaging ◽  
Cell Function ◽  
Platelet Factor 4 ◽  
Water Soluble ◽  
Cell Level ◽  
Platelet Factor ◽  
Ligand Density ◽  
Heparin Complexes ◽  
Novel Method ◽  
Platelet Aggregates

SummaryWe report a strategy to generate by electron beam lithography high fidelity micropatterned arrays to assess the interaction of single platelets with immobilised ligands. As a proof-of-principle we functionalised the microarrays with platelet factor 4 (PF4)-heparin-IgG complexes. We embedded biotinylated water-soluble quantum dots into polyethylene glycol (PEG)-coated micropatterned arrays and functionalised them via streptavidin to bind biotinylated ligands, here biotinylated-PF4/heparin complexes. The integrity of the PF4/heparin-complexes was shown by binding of anti-PF4/heparin antibodies. Ligand density was quantified by immunofluorescence and immunogold antibody labelling. Real-time calcium imaging was employed for read-out of single platelets activated on micropatterned surfaces functionalised with PF4/heparin-IgG complexes. With the smallest micropatterns (0.5x0.5 µm) we show that single platelets become strongly activated by binding to surface-immobilised PF4/heparin-IgG, while on larger micropatterns (10x10 µm), platelet aggregates formed. These findings that HIT antibodies can cause platelet activation on microarrays illustrate how this novel method opens new avenues to study platelet function at single cell level. Generating functionalized microarray surfaces to which highly complex ligands can be bound and quantified has the potential for platelet and other cell function assays integrated into high-throughput microfluidic microdevices.

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