scholarly journals Beta-catenin signaling regulates barrier-specific gene expression in circumventricular organ and ocular vasculatures

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Yanshu Wang ◽  
Mark F Sabbagh ◽  
Xiaowu Gu ◽  
Amir Rattner ◽  
John Williams ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Area Postrema ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Brain Structures ◽  
Circumventricular Organs ◽  
Specific Gene ◽  
Beta Catenin ◽  
High Permeability ◽  
Wnt Inhibitory Factor 1

The brain, spinal cord, and retina are supplied by capillaries that do not permit free diffusion of molecules between serum and parenchyma, a property that defines the blood-brain and blood-retina barriers. Exceptions to this pattern are found in circumventricular organs (CVOs), small midline brain structures that are supplied by high permeability capillaries. In the eye and brain, high permeability capillaries are also present in the choriocapillaris, which supplies the retinal pigment epithelium and photoreceptors, and the ciliary body and choroid plexus, the sources of aqueous humor and cerebrospinal fluid, respectively. We show here that (1) endothelial cells in these high permeability vascular systems have very low beta-catenin signaling compared to barrier-competent endothelial cells, and (2) elevating beta-catenin signaling leads to a partial conversion of permeable endothelial cells to a barrier-type state. In one CVO, the area postrema, high permeability is maintained, in part, by local production of Wnt inhibitory factor-1.

scholarly journals Single-cell transcriptomics of the human retinal pigment epithelium and choroid in health and macular degeneration

2019 ◽  
Vol 116 (48) ◽  
pp. 24100-24107 ◽  
Author(s):  
Andrew P. Voigt ◽  
Kelly Mulfaul ◽  
Nathaniel K. Mullin ◽  
Miles J. Flamme-Wiese ◽  
Joseph C. Giacalone ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Retinal Pigment Epithelium ◽  
Macular Degeneration ◽  
Single Cell ◽  
Rna Sequencing ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Single Cell Rna Sequencing

The human retinal pigment epithelium (RPE) and choroid are complex tissues that provide crucial support to the retina. Disease affecting either of these supportive tissues can lead to irreversible blindness in the setting of age-related macular degeneration. In this study, single-cell RNA sequencing was performed on macular and peripheral regions of RPE-choroid from 7 human donor eyes in 2 independent experiments. In the first experiment, total RPE/choroid preparations were evaluated and expression profiles specific to RPE and major choroidal cell populations were identified. As choroidal endothelial cells represent a minority of the total RPE/choroidal cell population but are strongly implicated in age-related macular degeneration (AMD) pathogenesis, a second single-cell RNA-sequencing experiment was performed using endothelial cells enriched by magnetic separation. In this second study, we identified gene expression signatures along the choroidal vascular tree, classifying the transcriptome of human choriocapillaris, arterial, and venous endothelial cells. We found that the choriocapillaris highly and specifically expresses the regulator of cell cycle gene (RGCC), a gene that responds to complement activation and induces apoptosis in endothelial cells. In addition, RGCC was the most up-regulated choriocapillaris gene in a donor diagnosed with AMD. These results provide a characterization of the human RPE and choriocapillaris transcriptome, offering potential insight into the mechanisms of choriocapillaris response to complement injury and choroidal vascular disease in age-related macular degeneration.

Hypocrellin B Encapsulated in Triphenyl Phosphonium-Modified Cationic Liposomes for Photodynamic Treatment of Exudative Age-Related Macular Degeneration

2019 ◽  
Vol 15 (12) ◽  
pp. 2305-2320
Author(s):  
Hongxia Chen ◽  
Hong Deng ◽  
Xianbiao Zou ◽  
Jingquan Zhao
Keyword(s):  
Endothelial Cells ◽  
Macular Degeneration ◽  
Vascular Endothelial Cells ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Vascular Endothelial ◽  
Age Related ◽  
Triphenyl Phosphonium ◽  
Hypocrellin B

Verteporfin photodynamic therapy (PDT) has been approved for the treatment of exudative age-related macular degeneration (AMD) for over a decade. However, its extensive application has been impeded by inevitably collateral tissue damage and immediate induction of angiogenesis, in addition to the need of multiple treatments. In order to develop prospective photosensitizers for clinical use, a triphenyl phosphonium-modified cationic liposomal hypocrellin B (TPP cationic LHB) for angiogenic targeting and endothelial internalization was constructed. With optimal PDT parameters, TPP cationic LHB can lead to death of choroid-retinal vascular endothelial cells while cause negligible damage to collateral retinal pigment epithelium cells. This is likely due to the mitochondria targeting and effective intracellular singlet oxygen generation of TPP cationic LHB in vascular endothelial cells. Additionally, in vivo chick chorioallantoic membrane assay indicated the elevated neovessel-targeting ability and photo-induced anti-angiogenic activity of TPP cationic LHB. Furthermore, TPP cationic LHB PDT is able to maintain neovessel occlusion for an extended period of time compared with verteporfin PDT, without inducing significant increased expression of some angiogenic factors, such as vascular endothelial growth factor and integrin αvβ3. This study describes a facile strategy that may be useful for developing new-generation photosensitizers to circumvent the limitations of PDT treatment of exudative AMD.

scholarly journals Can Phage Display Be Used as a Tool to Functionally Identify Endogenous Eat-Me Signals in Phagocytosis?

2009 ◽  
Vol 14 (6) ◽  
pp. 653-661 ◽  
Author(s):  
Nora B. Caberoy ◽  
Yixiong Zhou ◽  
Wei Li
Keyword(s):  
Phage Display ◽  
Tyrosine Kinases ◽  
Milk Fat ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Biological Behavior ◽  
Specific Gene ◽  
Cellular Debris ◽  
Library Journal ◽  
Milk Fat Globule

Removal of apoptotic cells and cellular debris by phagocytosis is essential for development, tissue homeostasis, and resolution of inflammation. Eat-me signals control the initiation of phagocytosis, holding a key to the understanding of phagocyte biology. Because of a lack of functional cloning strategy, eat-me signals are conventionally identified and characterized on a case-by-case basis. The feasibility of functional cloning of eat-me signals by phage display is investigated by characterizing the biological behavior of T7 phages displaying 2 well-known eat-me signals: growth arrest—specific gene 6 (Gas6) and milk fat globule—EGF8 (MFG-E8). Gas6-phage binds to all 3 known Gas6 receptors: Mer, Axl, and Tyro3 receptor tyrosine kinases. Gas6-phage and MFG-E8-phage are capable of binding to phagocytes and nonphagocytes. However, both phages stimulate phage uptake only in phagocytes, including macrophages, microglia, and retinal pigment epithelium cells, but not in nonphagocytes. Furthermore, functional phage selection by phagocytosis in phagocytes enriches both Gas6-phage and MFG-E8-phage, suggesting that phage display can be used as a tool to functionally identify unknown eat-me signals from phage display cDNA library. ( Journal of Biomolecular Screening 2009:653-661)

scholarly journals Identification of a synergistic interaction between endothelial cells and retinal pigment epithelium

2017 ◽  
Vol 21 (10) ◽  
pp. 2542-2552 ◽  
Author(s):  
Carrie Spencer ◽  
Stephanie Abend ◽  
Kevin J. McHugh ◽  
Magali Saint-Geniez
Keyword(s):  
Endothelial Cells ◽  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Synergistic Interaction

Lesions of area postrema and subfornical organ alter exendin-4-induced brain activation without preventing the hypophagic effect of the GLP-1 receptor agonist

2010 ◽  
Vol 298 (4) ◽  
pp. R1098-R1110 ◽  
Author(s):  
Elena-Dana Baraboi ◽  
Pauline Smith ◽  
Alastair V. Ferguson ◽  
Denis Richard
Keyword(s):  
Area Postrema ◽  
Brain Structures ◽  
Circumventricular Organs ◽  
Primary Objective ◽  
Subfornical Organ ◽  
Metabolic Effects ◽  
Ventrolateral Medulla ◽  
Hypothalamic Nucleus ◽  
Medial Nucleus ◽  
Electrolytic Ablation

The mechanism and route whereby glucagon-like peptide 1 (GLP-1) receptor agonists, such as GLP-1 and exendin-4 (Ex-4), access the central nervous system (CNS) to exert their metabolic effects have yet to be clarified. The primary objective of the present study was to investigate the potential role of two circumventricular organs (CVOs), the area postrema (AP) and the subfornical organ (SFO), in mediating the metabolic and CNS-stimulating effects of Ex-4. We demonstrated that electrolytic ablation of the AP, SFO, or AP + SFO does not acutely prevent the anorectic effects of Ex-4. AP + SFO lesion chronically decreased food intake and body weight and also modulated the effect of Ex-4 on the neuronal activation of brain structures involved in the hypothalamic-pituitary-adrenal axis and glucose metabolism. The results of the study also showed that CVO lesions blunted Ex-4-induced expression of c- fos mRNA (a widely used neuronal activity marker) in 1) limbic structures (bed nucleus of the stria terminalis and central amygdala), 2) hypothalamus (paraventricular hypothalamic nucleus, supraoptic nucleus, and arcuate nucleus), and 3) hindbrain (lateral and lateral-external parabrachial nucleus, medial nucleus of the solitary tract, and ventrolateral medulla). In conclusion, although the present results do not support a role for the CVOs in the anorectic effect induced by a single injection of Ex-4, they suggest that the CVOs play important roles in mediating the actions of Ex-4 in the activation of CNS structures involved in homeostatic control.

scholarly journals In vitro evaluation of simulated stereotactic radiotherapy for wet age-related macular degeneration on three different cell lines

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Efstathios Vounotrypidis ◽  
Anna Hillenmayer ◽  
Christian M. Wertheimer ◽  
Alexis Athanasiou ◽  
Jakob Siedlecki ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Death ◽  
Stereotactic Radiotherapy ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Low Energy ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Brdu Assay

AbstractLow energy stereotactic radiotherapy has been proposed for the treatment of neovascular age related macular degeneration. We investigated the in vitro effect of the radiotherapy on pericytes, retinal pigment epithelium and endothelial cells. Primary human retinal pigment epithelium cells, human umbilical vein endothelial cells and human pericytes from Placenta were cultivated. In a pairwise protocol, one plate was irradiated at a dose of 16 Gy, while the second plate served as a non-irradiated control. Thereafter, cells were cultivated either in serum-free (non-permissive) or serum-stimulated (permissive) conditions. A life/dead assay, an XTT and a BrdU assay were performed up to 7 days after irradiation. No cell death occurred at any timepoint in any cell line after treatment nor in the control. Compared to the unirradiated controls, cell viability and metabolic activity were significantly reduced in irradiated cells in the XTT assay, except for non-permissive RPE cells. In the BrdU assay, proliferation was inhibited. While no cell death was detected in vitro, viability and proliferative capacity of all cell lines were significantly reduced. Therefore, it seems that low energy stereotactic radiotherapy inhibits angiogenesis without a direct induction of apoptosis but influencing microvascular function and stability.

scholarly journals Stable Retinoid Analogue Targeted Dual pH-Sensitive Smart Lipid ECO/pDNA Nanoparticles for Specific Gene Delivery in the Retinal Pigment Epithelium

2020 ◽  
Vol 3 (5) ◽  
pp. 3078-3086 ◽  
Author(s):  
Da Sun ◽  
Rebecca M. Schur ◽  
Avery E. Sears ◽  
Song-Qi Gao ◽  
Wenyu Sun ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Gene Delivery ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Ph Sensitive ◽  
Specific Gene

scholarly journals Cell Stiffening Contributes to Complement-mediated Injury of Choroidal Endothelial Cells in Early AMD

2021 ◽  
Author(s):  
Andrea P Cabrera ◽  
Jonathan Stoddard ◽  
Irene Santiago Tierno ◽  
Nikolaos Matisioudis ◽  
Mahesh Agarwal ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Membrane Attack Complex ◽  
Small Gtpases ◽  
Age Related Macular Degeneration ◽  
Cell Stiffness ◽  
Age Related ◽  
Dry Amd ◽  
Choroidal Vessels

Age-related macular degeneration (AMD) is the leading cause of blindness in the aging population. Yet, no therapies exist for ~85% of all AMD patients who have the dry form that is marked by degeneration of the retinal pigment epithelium (RPE) and underlying choroidal vasculature. As the choroidal vessels are crucial for RPE development and maintenance, understanding how they degenerate may lead to effective therapies for dry AMD. One likely causative factor for choroidal vascular loss is the cytolytic membrane attack complex (MAC) of the complement pathway that is abundant on choroidal vessels of humans with early dry AMD. To examine this possibility, we studied the effect of complement activation on choroidal endothelial cells (ECs) isolated from a rhesus monkey model of early AMD that, we report, exhibits MAC deposition and choriocapillaris endothelial loss similar to that seen in human early AMD. Treatment of choroidal ECs from AMD eyes with complement-competent normal human serum caused extensive actin cytoskeletal injury that was significantly less pronounced in choroidal ECs from young normal monkey eyes. We further show that ECs from AMD eyes are significantly stiffer than their younger counterparts and exhibit peripheral actin organization that is distinct from the longitudinal stress fibers in young ECs. Finally, these differences in complement susceptibility and mechanostructural properties were found to be regulated by the differential activity of small GTPases Rac and Rho because Rac inhibition in AMD cells led to simultaneous reduction in stiffness and complement susceptibility while Rho inhibition in young cells exacerbated complement injury. Thus, by identifying cell stiffness and cytoskeletal regulators Rac and Rho as important determinants of complement susceptibility, the current findings offer a new mechanistic insight into choroidal vascular loss in early AMD that warrants further investigation for assessment of translational potential.

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