scholarly journals Α-Melanocyte-Stimulating Hormone Protects Early Diabetic Retina from Blood-Retinal Barrier Breakdown and Vascular Leakage via MC4R

2018 ◽  
Vol 45 (2) ◽  
pp. 505-522 ◽  
Author(s):  
Siwei Cai ◽  
Qianhui Yang ◽  
Mengzhu Hou ◽  
Qian Han ◽  
Hanyu Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Vascular Leakage ◽  
Inflammatory Factors ◽  
Protective Effects ◽  
Blood Retinal Barrier ◽  
Melanocyte Stimulating Hormone ◽  
Diabetic Retina ◽  
Pathogenic Factors ◽  
Brb Breakdown

Background/Aims: Blood-retinal barrier (BRB) breakdown and vascular leakage is the leading cause of blindness of diabetic retinopathy (DR). Hyperglycemia-induced oxidative stress and inflammation are primary pathogenic factors of this severe DR complication. An effective interventional modality against the pathogenic factors during early DR is needed to curb BRB breakdown and vascular leakage. This study sought to examine the protective effects of α-Melanocyte-stimulating hormone (α-MSH) on early diabetic retina against vascular hyperpermeability, electrophysiological dysfunction, and morphological deterioration in a rat model of diabetes and probe the mechanisms underlying the α-MSH’s anti-hyperpermeability in both rodent retinas and simian retinal vascular endothelial cells (RF6A). Methods: Sprague Dawley rats were injected through tail vein with streptozotocin to induce diabetes. The rats were intravitreally injected with α-MSH or saline at Week 1 and 3 after hyperglycemia. In another 2 weeks, Evans blue assay, transmission electron microscopy, electroretinogram (ERG), and hematoxylin and eosin (H&E) staining were performed to examine the protective effects of α-MSH in diabetic retinas. The expression of pro-inflammatory factors and tight junction at mRNA and protein levels in retinas was analyzed. Finally, the α-MSH’s anti-hyperpermeability was confirmed in a high glucose (HG)-treated RF6A cell monolayer transwell culture by transendothelial electrical resistance (TEER) measurement and a fluorescein isothiocyanate-Dextran assay. Universal or specific melanocortin receptor (MCR) blockers were also employed to elucidate the MCR subtype mediating α-MSH’s protection. Results: Evans blue assay showed that BRB breakdown and vascular leakage was detected, and rescued by α-MSH both qualitatively and quantitatively in early diabetic retinas; electron microscopy revealed substantially improved retinal and choroidal vessel ultrastructures in α-MSH-treated diabetic retinas; scotopic ERG suggested partial rescue of functional defects by α-MSH in diabetic retinas; and H&E staining revealed significantly increased thickness of all layers in α-MSH-treated diabetic retinas. Mechanistically, α-MSH corrected aberrant transcript and protein expression of pro-inflammatory factor and tight junction genes in the diseased retinas; moreover, it prevented abnormal changes in TEER and permeability in HG-stimulated RF6A cells, and this anti-hyperpermeability was abolished by a universal MCR blocker or an antagonist specific to MC4R. Conclusions: This study showed previously undescribed protective effects of α-MSH on inhibiting BRB breakdown and vascular leakage, improving electrophysiological functions and morphology in early diabetic retinas, which may be due to its down-regulating pro-inflammatory factors and augmenting tight junctions. α-MSH acts predominantly on MC4R to antagonize hyperpermeability in retinal microvessel endothelial cells.

scholarly journals Decursin Inhibits VEGF-Mediated Inner Blood—Retinal Barrier Breakdown by Suppression of VEGFR-2 Activation

2009 ◽  
Vol 29 (9) ◽  
pp. 1559-1567 ◽  
Author(s):  
Jin Hyoung Kim ◽  
Jeong Hun Kim ◽  
You Mie Lee ◽  
Eun-Mi Ahn ◽  
Kyu-Won Kim ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tight Junction ◽  
Vision Loss ◽  
Retinal Vessels ◽  
Tight Junction Proteins ◽  
Blood Retinal Barrier ◽  
Retinal Endothelial Cells ◽  
Extracellular Signal ◽  
Brb Breakdown ◽  
Junction Proteins

The blood—retinal barrier (BRB) is essential for the normal structural and functional integrity of the retina, whose breakdown could cause the serious vision loss. Vascular endothelial growth factor (VEGF), as a permeable factor, induces alteration of tight junction proteins to result in BRB breakdown. Herein, we demonstrated that decursin inhibits VEGF-mediated inner BRB breakdown through suppression of VEGFR-2 signaling pathway. In retinal endothelial cells, decursin inhibited VEGF-mediated hyperpermeability. Decursin prevented VEGF-mediated loss of tight junction proteins including zonula occludens-1 (ZO-1), ZO-2, and occludin in retinal endothelial cells, which was also supported by restoration of tight junction proteins in intercellular junction. In addition, decursin significantly inhibited VEGF-mediated vascular leakage from retinal vessels, which was accompanied by prevention of loss of tight junction proteins in retinal vessels. Decursin significantly suppressed VEGF-induced VEGFR-2 phosphrylation that consequently led to inhibition of extracellular signal-regulated kinase (ERK) 1/2 activation. Moreover, decursin induced no cytotoxicity to retinal endothelial cells and no retinal toxicity under therapeutic concentrations. Therefore, our results suggest that decursin prevents VEGF-mediated BRB breakdown through blocking of loss of tight junction proteins, which might be regulated by suppression of VEGFR-2 activation. As a novel inhibitor to BRB breakdown, decursin could be applied to variable retinopathies with BRB breakdown.

scholarly journals Primary cilia are present on endothelial cells of the hyaloid vasculature but are not required for the development of the blood-retinal barrier

2019 ◽  
Author(s):  
Lana M. Pollock ◽  
Brian Perkins ◽  
Bela Anand-Apte
Keyword(s):  
Endothelial Cells ◽  
Primary Cilia ◽  
Fluorescent Protein ◽  
Intraflagellar Transport ◽  
Mouse Retina ◽  
Transgenic Zebrafish ◽  
Blood Retinal Barrier ◽  
Retinal Microvasculature ◽  
Brb Breakdown ◽  
Hyaloid Vasculature

AbstractEndothelial cilia are found in a variety of tissues including the cranial vasculature of zebrafish embryos. Recently, endothelial cells in the developing mouse retina were reported to also possess primary cilia that are potentially involved in vascular remodeling. Fish carrying mutations in intraflagellar transport (ift) genes have disrupted cilia and have been reported to have an increased rate of spontaneous intracranial hemorrhage (ICH), potentially due to disruption of the sonic hedgehog (shh) signaling pathway. However, it remains unknown whether the endothelial cells forming the retinal microvasculature in zebrafish also possess cilia, and whether endothelial cilia are necessary for development and maintenance of the blood-retinal barrier (BRB). In the present study, we found that the endothelial cells lining the zebrafish hyaloid vasculature possess primary cilia during development. To determine whether endothelial cilia are necessary for BRB integrity, ift57, ift88, and ift172 mutants, which lack cilia, were crossed with the double-transgenic zebrafish strain Tg(l-fabp:DBP-EGFP;flk1:mCherry). This strain expresses a vitamin D-binding protein (DBP) fused to enhanced green fluorescent protein (EGFP) as a tracer in the blood plasma, while the endothelial cells forming the vasculature are tagged by mCherry. The Ift mutant fish develop a functional BRB, indicating that endothelial cilia are not necessary for early BRB integrity. Additionally, although treatment of zebrafish larvae with shh inhibitor cyclopamine results in BRB breakdown, the Ift mutant fish were not sensitized to cyclopamine-induced BRB breakdown.

scholarly journals Dihydrotanshinone, a Natural Diterpenoid, Preserves Blood-Retinal Barrier Integrity via P2X7 Receptor

2020 ◽  
Vol 21 (23) ◽  
pp. 9305
Author(s):  
Claudia Giuseppina Fresta ◽  
Giuseppe Caruso ◽  
Annamaria Fidilio ◽  
Chiara Bianca Maria Platania ◽  
Nicolò Musso ◽  
...  
Keyword(s):  
Virtual Screening ◽  
High Glucose ◽  
P2x7 Receptor ◽  
Therapeutic Potential ◽  
Protective Effects ◽  
Blood Retinal Barrier ◽  
Enhanced Production ◽  
New Findings ◽  
Brb Breakdown

Activation of P2X7 signaling, due to high glucose levels, leads to blood retinal barrier (BRB) breakdown, which is a hallmark of diabetic retinopathy (DR). Furthermore, several studies report that high glucose (HG) conditions and the related activation of the P2X7 receptor (P2X7R) lead to the over-expression of pro-inflammatory markers. In order to identify novel P2X7R antagonists, we carried out virtual screening on a focused compound dataset, including indole derivatives and natural compounds such as caffeic acid phenethyl ester derivatives, flavonoids, and diterpenoids. Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) rescoring and structural fingerprint clustering of docking poses from virtual screening highlighted that the diterpenoid dihydrotanshinone (DHTS) clustered with the well-known P2X7R antagonist JNJ47965567. A human-based in vitro BRB model made of retinal pericytes, astrocytes, and endothelial cells was used to assess the potential protective effect of DHTS against HG and 2′(3′)-O-(4-Benzoylbenzoyl)adenosine-5′-triphosphate (BzATP), a P2X7R agonist, insult. We found that HG/BzATP exposure generated BRB breakdown by enhancing barrier permeability (trans-endothelial electrical resistance (TEER)) and reducing the levels of ZO-1 and VE-cadherin junction proteins as well as of the Cx-43 mRNA expression levels. Furthermore, HG levels and P2X7R agonist treatment led to increased expression of pro-inflammatory mediators (TLR-4, IL-1β, IL-6, TNF-α, and IL-8) and other molecular markers (P2X7R, VEGF-A, and ICAM-1), along with enhanced production of reactive oxygen species. Treatment with DHTS preserved the BRB integrity from HG/BzATP damage. The protective effects of DHTS were also compared to the validated P2X7R antagonist, JNJ47965567. In conclusion, we provided new findings pointing out the therapeutic potential of DHTS, which is an inhibitor of P2X7R, in terms of preventing and/or counteracting the BRB dysfunctions elicited by HG conditions.

scholarly journals Klebsiella pneumoniae Induces an Inflammatory Response in anIn VitroModel of Blood-Retinal Barrier

2013 ◽  
Vol 82 (2) ◽  
pp. 851-863 ◽  
Author(s):  
C. Motta ◽  
M. Salmeri ◽  
C. D. Anfuso ◽  
A. Amodeo ◽  
M. Scalia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Klebsiella Pneumoniae ◽  
Endogenous Endophthalmitis ◽  
Prostaglandin E ◽  
Sodium Fluorescein ◽  
Blood Retinal Barrier ◽  
Retinal Endothelial Cells ◽  
Content Type ◽  
Retinal Pericytes

ABSTRACTKlebsiella pneumoniaehas become an important pathogen in recent years. Although most cases ofK. pneumoniaeendogenous endophthalmitis occur via hematogenous spread, it is not yet clear which microbial and host factors are responsible for the ability ofK. pneumoniaeto cross the blood-retinal barrier (BRB). In the present study, we show that in anin vitromodel of BRB based on coculturing primary bovine retinal endothelial cells (BREC) and primary bovine retinal pericytes (BRPC),K. pneumoniaeinfection determines changes of transendothelial electrical resistance (TEER) and permeability to sodium fluorescein. In the coculture model, bacteria are able to stimulate the enzyme activities of endothelial cytosolic and Ca2+-independent phospholipase A2s (cPLA2and iPLA2). These results were confirmed by the incremental expression of cPLA2, iPLA2, cyclo-oxygenase-1 (COX1), and COX2 in BREC, as well as by cPLA2phosphorylation. In supernatants ofK. pneumoniae-stimulated cocultures, increases in prostaglandin E2(PGE2), interleukin-6 (IL-6), IL-8, and vascular endothelial growth factor (VEGF) production were found. Incubation withK. pneumoniaein the presence of arachidonoyl trifluoromethyl ketone (AACOCF3) or bromoenol lactone (BEL) caused decreased PGE2and VEGF release. Scanning electron microscopy and transmission electron microscopy images of BREC and BRPC showed adhesion ofK. pneumoniaeto the cells, but no invasion occurred.K. pneumoniaeinfection also produced reductions in pericyte numbers; transfection of BREC cocultured with BRPC and of human retinal endothelial cells (HREC) cocultured with human retinal pericytes (HRPC) with small interfering RNAs (siRNAs) targeted to cPLA2and iPLA2restored the pericyte numbers and the TEER and permeability values. Our results show the proinflammatory effect ofK. pneumoniaeon BREC, suggest a possible mechanism by which BREC and BRPC react to theK. pneumoniaeinfection, and may provide physicians and patients with new ways of fighting blinding diseases.

scholarly journals Mechanically Stretched Mesenchymal Stem Cells Can Reduce the Effects of LPS-Induced Injury on the Pulmonary Microvascular Endothelium Barrier

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jin-ze Li ◽  
Shan-shan Meng ◽  
Xiu-Ping Xu ◽  
Yong-bo Huang ◽  
Pu Mao ◽  
...  
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Mesenchymal Stem Cells ◽  
Mechanical Stretch ◽  
Inflammatory Factors ◽  
Microvascular Endothelial Cell ◽  
Therapeutic Effects ◽  
Protective Effects ◽  
Microvascular Endothelium

Mesenchymal stem cells (MSCs) may improve the treatment of acute respiratory distress syndrome (ARDS). However, few studies have investigated the effects of mechanically stretched -MSCs (MS-MSCs) in in vitro models of ARDS. The aim of this study was to evaluate the potential therapeutic effects of MS-MSCs on pulmonary microvascular endothelium barrier injuries induced by LPS. We introduced a cocultured model of pulmonary microvascular endothelial cell (EC) and MSC medium obtained from MSCs with or without mechanical stretch. We found that Wright-Giemsa staining revealed that MSC morphology changed significantly and cell plasma shrank separately after mechanical stretch. Cell proliferation of the MS-MSC groups was much lower than the untreated MSC group; expression of cell surface markers did not change significantly. Compared to the medium from untreated MSCs, inflammatory factors elevated statistically in the medium from MS-MSCs. Moreover, the paracellular permeability of endothelial cells treated with LPS was restored with a medium from MS-MSCs, while LPS-induced EC apoptosis decreased. In addition, protective effects on the remodeling of intercellular junctions were observed when compared to LPS-treated endothelial cells. These data demonstrated that the MS-MSC groups had potential therapeutic effects on the LPS-treated ECs; these results might be useful in the treatment of ARDS.

scholarly journals Naringin protects endothelial cells from apoptosis and inflammation by regulating the Hippo-YAP Pathway

2020 ◽  
Vol 40 (3) ◽  
Author(s):  
Hui Zhao ◽  
Meirong Liu ◽  
Hui Liu ◽  
Rong Suo ◽  
Chengzhi Lu
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cardiovascular Diseases ◽  
Cell Injury ◽  
Umbilical Vein ◽  
Density Lipoprotein ◽  
Underlying Mechanism ◽  
Inflammatory Factors ◽  
Protective Effects ◽  
Mesenchymal Transition

Abstract Atherosclerosis is the primary cause of several cardiovascular diseases. Oxidized low-density lipoprotein (ox-LDL)-induced apoptosis, endothelial–mesenchymal transition (EndMT), and inflammation are crucial for the progression of cardiovascular diseases, including atherosclerosis. Naringin, a major compound from tomatoes, grapefruits, and related citrus, reportedly exhibits potential protective effects during atherosclerosis development; however, its effect on ox-LDL-induced human umbilical vein endothelial cell (HUVEC) damage remains unknown. In the present study, we investigated the anti-apoptotic and anti-inflammatory activities of naringin against ox-LDL-induced endothelial cells, and the underlying mechanism. Naringin pretreatment significantly and concentration-dependently inhibited ox-LDL-induced cell injury and apoptosis. Additionally, naringin restored endothelial barrier integrity by preventing VE-cadherin disassembly and F-actin remodeling, and down-regulated pro-inflammatory factors like IL-1β, IL-6, and IL-18, in the HUVECs. We also demonstrated that naringin treatment restored ox-LDL-induced YAP (yes-associated protein) down-regulation, given the YAP-shRNA attenuated cytoprotective effect of naringin on ox-LDL-induced endothelial cell injury and apoptosis. Collectively, our data indicate that naringin reversed ox-LDL-triggered HUVEC apoptosis, EndMT, and inflammation by inhibiting the YAP pathway. Therefore, naringin may have a therapeutic effect on endothelial injury-related disorders.

scholarly journals Luo Tong Formula Alleviates Diabetic Retinopathy in Rats Through Micro-200b Target

2020 ◽  
Vol 11 ◽  
Author(s):  
Bing Pang ◽  
Qing Ni ◽  
Sha Di ◽  
Li-juan Du ◽  
Ya-li Qin ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Blood Glucose ◽  
Tight Junction ◽  
Diabetic Rats ◽  
Control Group ◽  
Protective Effects ◽  
Sprague Dawley ◽  
Blood Retinal Barrier ◽  
Tissue Samples ◽  
Brb Breakdown

Aim: Diabetic retinopathy (DR) is a serious complication of diabetes (DM). Luo Tong formula (LTF) exerts protective effects against DR in rats, but its underlying mechanism remains unknown. Methods: Sprague-Dawley rats injected with streptozotocin (STZ) were used as an experimental diabetes model. LTF or calcium dobesilate (CaD) was administered to diabetic rats via gastric gavage. After the 12 weeks of treatment, blood and tissue samples were collected to determine serum glucose and retinal structure. Blood samples were collected for blood glucose and hemorheology analysis. Gene or protein expression levels were evaluated by immunohistochemistry, western blotting and/or quantitative real-time polymerase chain reaction (PCR). Results: DM rats exhibits significantly increased blood retinal-barrier (BRB) breakdown and VEGF/VEGFR expression in the retina, and decreased miR-200b and tight junction ZO-1/Occludin/ Claudin-5 genes expression, as well as Ang-1/Tie-2 expressions in the retina compared to normal control group. LTF treatment significantly moderated histological abnormalities in diabetic rats, independent of blood glucose level; improved some hemorrheological parameters; decreased the expressions of VEGF/VEGFR and BRB breakdown, significantly increased PEDF and tight junction proteins ZO-1/Occludin, as well as increased retinal miR-200b expression compared to non-treatment diabetic rats. Moreover, LTF prevented the reduction in Ang-1/Tie-2 expression. Conclusions: LTF treatment ameliorated DR through its repair vascular and attenuate vascular leakage. A mechanism involving miR-200b may contribute to benefit effects.

scholarly journals Protective Effects of Resveratrol on TNF-α-Induced Endothelial Cytotoxicity in Baboon Femoral Arterial Endothelial Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Juan Xiao ◽  
Jun Song ◽  
Vida Hodara ◽  
Allen Ford ◽  
Xing Li Wang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Critical Role ◽  
Primary Cultures ◽  
Vascular Diseases ◽  
Cellular Adhesion ◽  
Inflammatory Factors ◽  
High Dose ◽  
Protective Effects ◽  
Cellular Adhesion Molecule ◽  
Arterial Endothelial Cells

Endothelial injury induced by inflammatory factors plays a critical role in the pathogenesis of cardiovascular disease. Endothelial cell (EC) apoptosis, proliferation, migration, and cellular adhesion molecule (CAM) expression contribute to the development of atherosclerosis. We investigated the effects of resveratrol (0.1–100 μM) on the proliferation, migration, and CAM expression of primary cultures of baboon arterial endothelial cells (BAECs). In addition, we tested its effects under normal conditions as well as under inflammatory conditions induced by tumour necrosis factor-α(TNF-α) administered either by cotreatment, pretreatment, or posttreatment. Immunocytochemistry, MTT, wound-healing, and flow cytometry assays were performed. The resveratrol treatment significantly enhanced BAEC proliferation and attenuated TNF-α-induced impairment of proliferation at the optimal doses of 1–50 µM. Resveratrol at a high dose (100 μM) and TNF-αimpaired BAEC migration, while low doses of resveratrol (1–50 μM) attenuated TNF-α-induced impairment of BAEC migration. Moreover, resveratrol inhibited TNF-α-induced ICAM-1 and VCAM-1 expression. Taken together, our results suggest that the resveratrol protects BAECs after inflammatory stimulation as well as ameliorates inflammatory effects at low concentrations. Consequently, resveratrol should be considered as a candidate drug for the prevention and treatment of inflammatory vascular diseases.

Complex Vesicles, Microtubules, and Cytoplasmic Filaments in the Endothelial Cells of Normal Dog Aorta

1968 ◽  
Vol 26 ◽  
pp. 172-173
Author(s):  
C. N. Sun ◽  
J. J. Ghidoni
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Cross Sections ◽  
Functional Significance ◽  
Tubular Structures ◽  
Aldehyde Fixation ◽  
Cytoplasmic Filaments

Endothelial cells in longitudinal and cross sections of aortas from 3 randomly selected “normal” mongrel dogs were studied by electron microscopy. Segments of aorta were distended with cold cacodylate buffered 5% glutaraldehyde for 10 minutes prior to being cut into small, well oriented tissue blocks. After an additional 1-1/2 hour period in glutaraldehyde, the tissue blocks were well rinsed in buffer and post-fixed in OsO4. After dehydration they were embedded in a mixture of Maraglas, D.E.R. 732, and DDSA.Aldehyde fixation preserves the filamentous and tubular structures (300 Å and less) for adequate demonstration and study. The functional significance of filaments and microtubules has been recently discussed by Buckley and Porter; the precise roles of these cytoplasmic components remains problematic. Endothelial cells in canine aortas contained an abundance of both types of structures.

Protective effects of soy-isoflavones in cardiovascular disease

2008 ◽  
Vol 28 (01/02) ◽  
pp. 85-88 ◽  
Author(s):  
D. Fuchs ◽  
H. Daniel ◽  
U. Wenzel
Keyword(s):  
Cardiovascular Disease ◽  
Endothelial Cells ◽  
Molecular Mechanisms ◽  
Dietary Intervention ◽  
Mononuclear Cells ◽  
Oxidized Ldl ◽  
Proteome Analysis ◽  
Soy Isoflavones ◽  
Protective Effects ◽  
Estrogen Production

SummaryEpidemiological studies indicate that the consumption of soy-containing food may prevent or slow-down the development of cardiovascular disease. In endothelial cells application of a soy extract or a combination of the most abundant soy isoflavones genistein and daidzein both inhibited apoptosis, a driving force in atherosclerosis development, when applied in combination with oxidized LDL or homocysteine. Proteome analysis revealed that the stressorinduced alteration of protein expression profile was reversed by the soy extract or the genistein/daidzein mixture. Only few protein entities that could be functionally linked to mitochondrial dysfunction were regulated in common by both application forms of isoflavones. A dietary intervention with isoflavone-enriched soy extract in postmenopausal women, who generally show strongly increased cardiovascular risk due to diminished estrogen production, led to significant alterations in the steady state levels of proteins from mononuclear blood cells. The proteins identified by proteome analysis revealed that soy isoflavones may increase the anti-inflammatory response in blood mononuclear cells thereby contributing to the atherosclerosispreventive activities of a soy-rich diet. Conclusion: By proteome analysis protein targets were identified in vitro in endothelial cells that respond to soy isoflavones and that may decipher molecular mechanisms through which soy products exert their protective effects in the vasculature.

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