Conditional loss of Ube3d in the retinal pigment epithelium accelerates age-associated alterations in the retina of mice.

Several studies have suggested a correlation between the ubiquitin-proteasome system (UPS) and age-related macular degeneration (AMD), with its phenotypic severity ranging from mild visual impairment to blindness, but the mechanism for UPS dysfunction contributing to disease progression is unclear. In this study, we investigated the role of ubiquitin protein ligase E3D (UBE3D) in aging and degeneration in mouse retina. Conditional knockout of Ube3d in the retinal pigment epithelium (RPE) of mice led to progressive and irregular fundus lesions, attenuation of the retinal vascular system, and age-associated deterioration of rod and cone responses. Simultaneously, RPE-specific Ube3d knockout mice also presented morphological changes similar to the histopathological characteristics of human AMD, in which a defective UPS led to RPE abnormalities such as phagocytosis or degradation of metabolites, the interaction with photoreceptor outer segment, and the transport of nutrients or waste products with choroidal capillaries via Bruch's membrane. Moreover, conditional loss of Ube3d resulted in aberrant molecular characterizations associated with the autophagy-lysosomal pathway, oxidative stress damage, and cell-cycle regulation, which are implicated in AMD pathology. Thus, our findings strengthen and expand the impact of UPS dysfunction on retinal pathophysiology during aging, indicating that genetic Ube3d deficiency in the RPE could lead to the abnormal formation of pigment deposits and secondary fundus alterations. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

More light components and less light damage on rats' eyes: evidence for the photobiomodulation and spectral opponency.

The blue-light hazard (BLH) has raised concerns with the increasing applications of white light-emitting diodes (LEDs). Many researchers believed that the shorter wavelength or more light components generally resulted in more severe retinal damage. In this study, based on the conventional phosphor-coated white LED, we added azure (484 nm), cyan (511 nm), and red (664 nm) light to fabricate the low-hazard light source. The low-hazard light sources and conventional white LED illuminated 68 Sprague-Dawley (SD) rats for 7 days. Before and after light exposure, we measured the retinal function, thickness of retinal layers, and fundus photographs. The expression levels of autophagy-related proteins and the activities of oxidation-related biochemical indicators were also measured to investigate the mechanisms of damaging or protecting the retina. With the same correlated color temperature (CCT), the low-hazard light source results in significantly less damage on the retinal function and photoreceptors, even if it has two times illuminance and blue-light hazard-weighted irradiance ([Formula: see text]) than conventional white LED. The results illustrated that [Formula: see text] proposed by IEC 62471 could not exactly evaluate the light damage on rats' retinas. We also figured out that more light components could result in less light damage, which provided evidence for the photobiomodulation (PBM) and spectral opponency on light damage.

Human RGR Gene and Associated Features of Age-Related Macular Degeneration in Models of Retina-Choriocapillaris Atrophy.

Age-related macular degeneration (AMD) is a progressive eye disease and the most common cause of blindness among the elderly. AMD is characterized by early atrophy of the choriocapillaris and retinal pigment epithelium (RPE). Although AMD is a multifactorial disease with many environmental and genetic risk factors, a hallmark of the disease is the origination of extracellular deposits, or drusen, between the RPE and Bruch membrane. Human retinal G-protein-coupled receptor (RGR) gene generates an exon-skipping splice variant of RGR-opsin (RGR-d; NP_001012740) that is a persistent component of small and large drusen. Herein, the findings show that abnormal RGR proteins, including RGR-d, are pathogenic in an animal retina with degeneration of the choriocapillaris, RPE, and photoreceptors. A frameshift truncating mutation resulted in severe retinal degeneration with a continuous band of basal deposits along the Bruch membrane. RGR-d produced less severe disease with choriocapillaris and RPE atrophy, including focal accumulation of abnormal RGR-d protein at the basal boundary of the RPE. Degeneration of the choriocapillaris was marked by a decrease in endothelial CD31 protein and choriocapillaris breakdown at the ultrastructural level. Fundus lesions with patchy depigmentation were characteristic of old RGR-d mice. RGR-d was mislocalized in cultured cells and caused a strong cell growth defect. These results uphold the notion of a potential hidden link between AMD and a high-frequency RGR allele.

Ocular phenotype and genetical analysis in patients with retinopathy of prematurity.

BACKGROUND: Retinopathy of prematurity (ROP) is a multifactorial retinal disease, involving both environmental and genetic factors; The purpose of this study is to evaluate the clinical presentations and genetic variants in Chinese patients with ROP. METHODS: A total of 36 patients diagnosed with ROP were enrolled in this study, their medical and ophthalmic histories were obtained, and comprehensive clinical examinations were performed. Genomic DNA was isolated from peripheral blood of ROP patients, polymerase chain reaction and direct sequencing of the associated pathogenic genes (FZD4, TSPAN12, and NDP) were performed. RESULTS: All patients exhibited the clinical manifestations of ROP. No mutations were detected in the TSPAN12 and NDP genes in all patients; Interestingly, three novel missense mutations were identified in the FZD4 gene (p.A2P, p.L79M, and p.Y378C) in four patients, for a detection rate of 11.1% (4/36). CONCLUSIONS: This study expands the genotypic spectrum of FZD4 gene in ROP patients, and our findings underscore the importance of obtaining molecular analyses and comprehensive health screening for this retinal disease.

7-Methylxanthine Influences the Behavior of ADORA2A-DRD2 Heterodimers in Human Retinal Pigment Epithelial Cells.

INTRODUCTION: The goal of this study was to investigate the presence of ADORA2A-DRD2 heterodimers in human retinal pigment epithelial (RPE) cells; determine if 7-methylxanthine (7-MX), a nonselective adenosine receptor antagonist which was used to control myopia progression, can influence the behavior of RPE cells through the ADORA2A-DRD2 receptor pathway; and assess the changes in the expression of signaling molecules during cellular signal transduction. METHODS: Human RPE cells were cultured in vitro in the presence or absence of 7-MX. Cell proliferation was evaluated with the CCK-8 assay. Apoptosis and necrosis rates were determined by annexin V-FITC/propidium iodide staining and flow cytometry. Immunofluorescence and coimmunoprecipitation were used to examine the protein expression and colocalization of ADORA2A and DRD2 in RPE cells. ADORA2A and DRD2 were knocked down with small interfering RNAs (siRNAs). Changes in the protein expression of ERK1/2 and phospho-ERK1/2 (pERK 1/2), which are signaling molecules downstream of dopamine receptors, were evaluated by Western blot analysis. RESULTS: Immunofluorescence and coimmunoprecipitation showed that ADORA2A and DRD2 were colocalized in RPE cells. The expression of ADORA2A in RPE cells was inhibited by treatment with 50 µmol/L 7-MX for 48 h, and the expression of DRD2, ERK1/2, and pERK1/2 was increased after treatment with 50 µmol/L 7-MX for 48 h. After siRNA-mediated knockdown of DRD2 in RPE cells and further treatment with 50 µmol/L 7-MX for 48 h, the expression of DRD2 was nearly restored to the level observed in the native control. At the experimental concentrations, 7-MX and siRNAs did not affect the proliferation or apoptosis of human RPE cells. CONCLUSIONS: ADORA2A and DRD2 heterodimers were present in RPE cells. 7-MX may affect the behaviors of RPE cells through the ADORA2A-DRD2 receptor pathway. 7-MX is an inhibitor of ADORA2A receptors that can prevent inhibition of the DRD2 receptor pathway and increase DRD2 receptor pathway activity. This phenomenon may explain the mechanism of action through which 7-MX can control myopia progression.

Dynamic Observation: Immune-Privileged Microenvironment Limited the Effectiveness of Immunotherapy in an Intraocular Metastasis Mouse Model.

INTRODUCTION: Intraocular metastasis (IM) occurred in approximately 8-10% of patients with metastatic malignancy, for whom oncological immunotherapies showed poor visual potential. However, the mechanism for that inefficiency remains unclear and requires further exploration. METHODS: We established a novel mouse model of IM by intracarotid injection of cutaneous melanoma cells. We investigated disease progression using ophthalmic and histological examinations. We used combined anti-PD-1 and anti-CTLA4 antibodies for immunotherapy and evaluated the therapeutic effects in the mouse model. In addition, we characterized the immune microenvironment of tumor-infiltrating CD8+ T by fluorescence staining and assessed their cytotoxicity by flow cytometry. RESULTS: All mice presented IM in the left eye, while the right eye was healthy. Uveal tissues with rich vascularity (e.g., the iris, ciliary body, and choroid) initiated IM at an early stage, and IM development resulted in several secondary changes, including corneal swelling, retinal detachment, and intratumoral hemorrhage. Immunotherapy could inhibit IM and prolong the time to eye rupture but did not prevent rupture ending. This inefficiency might be attributed to ocular tissues specificities that inhibited CD8+ T-cell infiltration via PD-L1 expression. PD-L1low corneal tissue resisted tumor invasion with high levels of CD8+ T-cell infiltration, whereas CD8+ T cells were deficient in PD-L1high uveal metastasis. Furthermore, we found a significantly increased PD-1+/- CD4+ and PD-1+/- CD8+ T cells infiltrating the intratumoral hemorrhage area. Although these CD8+ T cells in the IM were not exhausted and had a higher capacity of cytotoxicity (higher interferon-γ ratio) than CD8+ T cells in the blood, FasL+ PD-L1+ ocular tissue can strongly inhibit these IM-infiltrating T cells. CONCLUSIONS: Immunotherapy can inhibit the disease progression of IM. Enhancing the effects of tumor-infiltrating CD8+ T cells should be one of the highest potentials to improve the visual potential.

Asthma Promotes Choroidal Neovascularization via the Transforming Growth Factor Beta1/Smad Signalling Pathway in a Mouse Model.

INTRODUCTION: The association between age-related macular degeneration and asthma is controversial. Transforming growth factor beta (TGF-ß), which plays a critical role in asthma, has been extensively studied with regard to its function in choroidal neovascularization (CNV). In the present study, we aimed to investigate the role of TGF-ß and the possible mechanism of CNV formation complicated with asthma and to explore the effect of a TGF-ß inhibitor on CNV development in asthma mouse models. METHODS: Laser-induced CNV and ovalbumin-induced asthma mouse models were divided into 5 groups: control group, acute asthma group, chronic asthma group, inhibitor-treated acute asthma group, and inhibitor-treated chronic asthma group. The gene expression patterns of angiogenic cytokines, vascular endothelial growth factor (VEGF) receptors and inflammasomes in the control group, acute asthma group, and chronic asthma group were detected using a QuantiGene Plex 6.0 Reagent System. Fundus fluorescein angiography and histology of CNV lesions stained with haematoxylin-eosin were performed to evaluate CNV formation. Quantitative real-time PCR and western blotting were used to assess TGF-ß1, TGF-ß2, and VEGF expression and Smad2/3, AKT, p38 MAPK, and ERK1/2 signal transduction and phosphorylation in retinal and choroidal tissues from each group. RESULTS: In this study, we verified that laser treatment led to more CNV and vascular leakage in asthmatic mice than that in control mice. The changes were particularly notable in the chronic asthma group. The respective TGF-ß1, VEGF, and phosphorylated Smad2/3 (p-Smad2/3) mRNA and protein levels in retinal and choroidal tissues were significantly upregulated in both the acute and chronic asthma groups. After injection of a TGF-ß inhibitor, a distinct decline in VEGF, TGF-ß1, and p-Smad2/3 protein and mRNA levels was observed, and the mean CNV area also decreased. CONCLUSION: We provide new evidence that asthma could be a risk factor for CNV development via the TGF-ß1/Smad signalling pathway. A TGF-ß inhibitor can be applied as a useful, adjunctive therapeutic strategy for preventing CNV formation in asthmatic patients.

Plasma metabolomic profiling of central serous chorioretinopathy.

Our study aimed to investigate metabolites alterations in the blood plasma of central serous chorioretinopathy (CSC) patients and to identify the key biomarkers to increase the understanding of the mechanism of CSC at the molecular level. Quantitative and targeted metabolomics using liquid chromatography tandem-mass spectrometry (LCMS, Biocrates P500) assays were performed on plasma samples from the 42 subjects(CSC patients = 30, control = 12) enrolled at the Department of Ophthalmology of People's Hospital Peking University. A total of 61 altered metabolites were distinguished between CSC patients and controls. Taurine was selected as a candidate biomarker for CSC among 6 potential metobolites: taurine, glutamic acid, sarcosine, lactic acid, glutamine and C18_1. The P values of these potential metabolites were 1.01E-06, 7.35E-08, 1.27E-24, and 1.85E-10, 1.02E-05 and 8.59E-08, and the areas under the curve for them were 0.926, 0.991, 1.000, 0.900, 0.897 and 0.841, respectively. This study is the first to identify that taurine may be a biologically relevant biomarker for CSC and to provide a novel understanding of CSC.

Factors related to retinal nerve fiber layer thickness in bipolar disorder patients and major depression patients.

BACKGROUND: We analyzed the correlation of the clinical data with retinal nerve fiber layer (RNFL) thickness and macular thickness in bipolar disorder patients and major depression patients. The aim of this study is to explore factors that affect RNFL thickness in bipolar disorder patients and major depression patients, with a view to providing a new diagnostic strategy. METHODS: Eighty-two bipolar disorder patients, 35 major depression patients and 274 people who were age and gender matched with the patients were enrolled. Demographic information and metabolic profile of all participants were collected. Best-corrected visual acuity of each eye, intraocular pressure (IOP), fundus examination was performed. RNFL and macular thickness were measured by optical coherence tomography (OCT). Correlations between RNFL and macular thickness and other data were analyzed. RESULTS: RNFL and macula lutea in bipolar dipolar patients and major depression patients are thinner than normal people. Triglyceride and UA levels are the highest in the bipolar disorder group, while alanine aminotransferase (ALT) and glutamic oxalacetic transaminase (AST) levels in the depression group are the highest. Age onset and ALT are positively while uric acid (UA) is negatively correlated with RNFL thickness in bipolar dipolar patients. Cholesterol level is positively correlated with RNFL thickness while the duration of illness is correlated with RNFL thickness of left eye in major depression patients. CONCLUSIONS: RNFL and macula lutea in bipolar dipolar patients and major depression patients are thinner than normal people. In bipolar disorder patients, age-onset and ALT are potential protective factors in the progress of RNFL thinning, while UA is the pathological factor.

RNA-Seq Analysis for Exploring the Pathogenesis of Retinitis Pigmentosa in P23H Knock-In Mice.

INTRODUCTION: Mechanisms contributing to the progression of autosomal dominant retinitis pigmentosa (adRP) due to the P23H rhodopsin mutation are complex and diverse. Previous studies showed that mechanisms like endoplasmic reticulum (ER) stress, pyroptosis, and oxidative stress were involved in the pathogenesis of the disease. However, the roles and relationships of different mechanisms are not precisely known. In this study, we aimed to evaluate certain mechanisms and find novel genes involved in P23H-related adRP. METHODS: Total RNA extracted at postnatal day (PN) 14, PN21, and PN35 was used for RNA sequencing. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analyses were conducted for RNA-seq data. Additionally, data from the clustered regularly interspaced short palindromic repeats (CRISPR) screening library and the RNA-seq data of several mechanisms were used for generating custom gene sets for gene set enrichment analysis (GSEA). Next, we obtained the intersection of the aforementioned gene sets and our RNA-seq data to identify candidate genes, which were verified using real-time quantitative PCR (qPCR). RESULTS: Functional enrichment analyses were consistent with disease phenotypes. All time points observed pyroptosis. In the results of GSEA, ER stress, pyroptosis, and oxidative stress were observed at PN14. ER stress and pyroptosis were shown on PN35. A total of 22 candidate genes were identified. The expression levels of selected genes verified by qPCR were concordant with the RNA-seq data. CONCLUSIONS: In our study, we conclude that pyroptosis and ER stress might play a central role in RP progression. We also identified differentially expressed gene clusters related to ER stress and pyroptosis, which deserve further study. These findings provide a novel perspective for the investigation of P23H-related adRP.

Disease-causing mutations associated with bestrophinopathies promote apoptosis in retinal pigment epithelium cells.

PURPOSE: Best vitelliform macular dystrophy (BVMD) and autosomal recessive bestrophinopathy (ARB) are two kinds of bestrophinopathies which are caused by BEST1 mutations and characterized by accumulation of lipofuscin-like materials on the retinal pigment epithelium cell-photoreceptor interface. In the past two decades, research about the pathogenesis of bestrophinopathies was mainly focused on the anion channel and intracellular Ca2+ signaling, but seldom concentrated on the function of retinal pigment epithelium (RPE) cells. In this study, we explored the possible effect of the three BEST1 mutations p.V143F, p.S142G, and p.A146T on the apoptosis in human fetal RPE cells. METHODS: Wild-type plasmid and mutant plasmids BEST1-pcDNA3.1 p.V143F, p.S142G, and p.A146T were transfected to human fetal RPE cells. The molecules caspase-3, phospho-Bcl-2, BAX, PARP, and AIF associated with apoptosis were determined by quantitative PCR and Western blot. Apoptotic rate and active Caspase-3 staining were analyzed by flow cytometry. RESULTS: Caspase-3 and PARP expression were significantly increased in BEST1-pcDNA3.1 p.S142G and p.A146T group. Flow cytometry showed that the apoptosis rates were significantly increased in the BEST1-pcDNA3.1 p.V143F, p.S142G, and p.A146T group compared with the wild-type group. CONCLUSIONS: For the first time, we found that the three mutations promoted RPE cell apoptosis. Furthermore, the results indicated that BEST1 mutations p.S142G and p.A146T may contribute apoptosis of RPE cells by targeting Caspase 3. Our observations suggested that the apoptosis of RPE cells may be one of the mechanisms in bestrophinopathies, which may provide a new potential therapeutic target for the treatment of this disease.

Association between CFH single nucleotide polymorphisms and response to photodynamic therapy in patients with central serous chorioretinopathy.

PURPOSE: To evaluate the association between single nucleotide polymorphisms (SNPs) in the complement factor H (CFH) gene and response to PDT in patients with CSC. METHODS: 103 eyes from 93 patients with CSC were enrolled from Department of Ophthalmology of the People's Hospital Peking University. Genotyping for selected SNPs in the CFH gene was performed, and multivariate linear analysis was used to identify factors influencing PDT treatment outcomes. Genetics associations between SNPs in the CFH gene and response to PDT in patients with CSC were analyzed. RESULTS: None of the seven SNPs examined in this study (rs800292, rs1061170, rs3753394, rs3753396, rs2284664, rs1329428, and rs1065489) showed significant associations with 1-month outcomes after PDT in patients with CSC (P > 0.05). Baseline BCVA changed at 1 month after PDT (P < 0.001), and baseline retinal thickness was associated with changes in retinal thickness at 1 month after PDT (P < 0.001). Age was significantly associated with resolution of SRF at 1 month after PDT (P = 0.004). CONCLUSIONS: There were no significant associations between SNPs in the CFH gene and 1-month outcomes after PDT in patients with CSC. However, baseline BCVA, baseline retinal thickness, and age were significantly associated with response to PDT in patients with CSC. Larger studies with more power are necessary to further determine whether an association exists between SNPs in the CFH gene and PDT in patients with CSC.

The effects of pleiotrophin in proliferative vitreoretinopathy.

PURPOSE: The purpose of our study was to investigate the effects of pleiotrophin (PTN) in proliferative vitreoretinopathy (PVR) both in vitro and in vivo. METHODS: Immunofluorescence was used to observe the PTN expression in periretinal membrane samples from patients with PVR and controls. ARPE-19 cells were exposed to TGF-ß1. The epithelial-to-mesenchymal transition (EMT) of the ARPE-19 cells was confirmed by observed morphological changes and the increased expression of α-SMA and fibronectin at both the mRNA and protein levels. We used specific small interfering (si)RNA to knock down the expression of PTN. The subsequent effects of PTN inhibition were assessed with regard to the EMT, migration, proliferation, cytoskeletal arrangement, TGF-ß signaling, PTN signaling, integral tight junction protein expression (e.g., claudin-1 and occludin), and p38 MAPK and p-p38 MAPK levels. Additionally, a PVR rat model was established by the intravitreal injection of ARPE-19 cells transfected with PTN-siRNA and was evaluated accordingly. RESULTS: PTN was highly expressed in PVR membranes compared to controls. PTN knockdown attenuated the TGF-ß1-induced migration, proliferation, cytoskeletal rearrangement, and expression of EMT markers such as α-SMA and fibronectin in the ARPE-19 cells, and these effects may have been mediated through p38 MAPK signaling pathway activation. PTN silencing inhibited the up-regulation of claudin-1 and occludin stimulated by TGF-ß1, and PTN knockdown inhibited the proliferative aspects of severe PVR in vivo. CONCLUSIONS: PTN is involved in the process of EMT induced by TGF-ß1 in human ARPE-19 cells in vitro, and PTN knockdown attenuated the progression of experimental PVR in vivo. These findings provide new insights into the pathogenesis of PVR.

SERUM LEVELS OF VASCULAR ENDOTHELIAL GROWTH FACTOR BEFORE AND AFTER INTRAVITREAL INJECTION OF RANIBIZUMAB OR CONBERCEPT FOR NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

OBJECTIVE: To investigate the serum levels of vascular endothelial growth factor (VEGF) before and after intravitreal injection of conbercept or ranibizumab for neovascular age-related macular degeneration and polypoidal choroidal vasculopathy patients. METHODS: This study is a prospective, interventional case series and involved 28 patients, 18 treated with 0.5 mg of conbercept and 10 treated with 0.5 mg of ranibizumab. Serum concentrations of VEGF were determined by enzyme-linked immunosorbent assay before the injection and at 1 day, 1 week, and 1 month after anti-VEGF treatments. RESULTS: The baseline serum VEGF level of the ranibizumab group was 367.11 ± 311.87 pg/mL, whereas that of the conbercept group was 315.06 ± 170.88 pg/mL (P = 0.653). In the conbercept group, VEGF level significantly decreased to 36.32 ± 72.11 pg/mL at 1 day (P = 0.03) and returned to 136.55 ± 144.62 pg/mL at 1 week (P = 0.03). At 1 month, the concentration increased to 334.48 ± 197.41 pg/mL and showed no significant difference compared with the baseline. In the ranibizumab group, the serum VEGF levels were 292.42 ± 239.80 pg/mL, 282.60 ± 201.36 pg/mL, and 308.83 ± 266.89 pg/mL at 1 day, 1 week, and 1 month after intravitreal injection, respectively. There was no significant difference in the ranibizumab group at each detection time point (P = 0.45). CONCLUSION: Conbercept significantly decreased serum VEGF level 1 day and 1 week after injection, but this effect was not sustained for 1 month. In contrast, ranibizumab had no significant effect on serum VEGF concentration changes. The reduction in serum VEGF by conbercept may affect its systemic safety profile.

Small Interfering RNA Targeted to ASPP2 Promotes Progression of Experimental Proliferative Vitreoretinopathy.

Background. Epithelial-mesenchymal transition (EMT) of retinal pigment epithelium (RPE) is vital in proliferative vitreoretinopathy (PVR) development. Apoptosis-stimulating proteins of p53 (ASPP2) have recently been reported to participate in EMT. However, the role of ASPP2 in PVR pathogenesis has not been identified. Methods. Immunohistochemistry was used to investigate the expression of ASPP2 in epiretinal membranes of PVR patients. ARPE-19 cells were transfected with ASPP2-siRNA, followed with measurement of cell cytotoxicity, proliferation, and migration ability. EMT markers and related inflammatory and fibrosis cytokines were measured by western blot or flow cytometry. Additionally, PVR rat models were induced by intravitreal injection of ARPE-19 cells transfected with ASPP2-siRNA and evaluated accordingly. Results. Immunofluorescence analysis revealed less intense expression of ASPP2 in PVR membranes. ASPP2 knockdown facilitated the proliferation and migration of RPE cells and enhanced the expression of mesenchymal markers such as alpha smooth muscle actin, fibronectin, and ZEB1. Meanwhile, ASPP2-siRNA increased EMT-related and inflammatory cytokines, including TGF-ß, CTGF, VEGF, TNF-α, and interleukins. PVR severities were more pronounced in the rat models with ASPP2-siRNA treatment. Conclusions. ASPP2 knockdown promoted EMT of ARPE-19 cells in vitro and exacerbated the progression of experimental PVR in vivo, possibly via inflammatory and fibrosis cytokines.

Effects of p75 neurotrophin receptor on regulating hypoxia-induced angiogenic factors in retinal pigment epithelial cells.

Retinal pigment epithelium (RPE) exerts critical roles in the maintenance of the normal functions of the retina, whereas RPE dysfunction can induce retina neovascularization. p75 neurotrophin receptor (p75(NTR)) has been shown to play essential roles in angiogenesis. However, the function of p75(NTR) in the RPE remains unclear. In the present study, we demonstrated that p75(NTR) was highly expressed in the human choroidal neovascularization membranes. For in vitro study, RPE was exposed to hypoxia, and a knockdown of p75(NTR) was achieved via lentivirus-mediated RNA interference. The results showed that hypoxia induced the expression of p75(NTR) in the RPE, and the knockdown of p75(NTR) rescued RPE proliferation activity and inhibited apoptosis which induced by hypoxia. After the deletion of p75(NTR), RPE-secreted pro-angiogenic factors (vascular endothelial growth factor and platelet-derived growth factor), inflammatory factors [interleukin 1 beta (IL1ß), IL18, and stromal cell-derived factor 1], and matrix metalloproteinases (MMPs) (MMP3 and MMP9) were down-regulated under hypoxic conditions. While the RPE secreted anti-angiogenic factors (pigment epithelium-derived factor) and angiostatin, the tissue inhibitors of metalloproteinases (TIMPs) (TIMP-1 and TIMP-3) were up-regulated after the knockdown of p75(NTR). The human umbilical vein endothelial tube formation ability can be inhibited when it is co-cultured with the supernatant extract from p75(NTR)-knockdown RPE under hypoxic induction. These results suggest that the knockdown of p75(NTR) suppressed pro-angiogenic factors which induced by hypoxia while promoting the anti-angiogenesis-related factors in the RPE. It is indicated that p75(NTR) could be a potential therapeutic target for RPE hypoxia or oxidative stress diseases.

Quercetin inhibits vascular endothelial growth factor-induced choroidal and retinal angiogenesis in vitro.

PURPOSE: The aim of this study was to investigate the effects of quercetin on vascular endothelial growth factor (VEGF)-induced choroidal and retinal angiogenesis in vitro using a rhesus macaque choroid-retinal endothelial (RF/6A) cell line. METHODS: RF/6A cells were cultured in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum. Then the cells were treated with different concentrations (from 0 to 100 µM) of quercetin and 100 ng/ml VEGF. The cell proliferation was assessed using cholecystokinin octapeptide dye. The cell migration was investigated by a Transwell assay. The tube formation was measured on Matrigel. Furthermore, the impact of quercetin's effects on VEGF-induced activation of VEGF receptor 2 (VEGFR-2) downstream signal pathways was tested by Western blot analysis. RESULTS: Quercetin inhibits RF/6A cell proliferation in a dose-dependent fashion: 22.7, 31.5 and 36.7% inhibition on treatment with 10, 50 and 100 µM quercetin, respectively. VEGF-induced migration and tube formation of RF/6A cells were also significantly inhibited by quercetin in a dose-dependent manner. Quercetin inhibits VEGF-induced VEGFR-2 downstream signal pathways of RF/6A. CONCLUSIONS: The results show that quercetin inhibits VEGF-induced cell proliferation, migration and tube formation of RF/6A. We suggest that quercetin inhibits VEGF-induced choroidal and retinal angiogenesis in vitro. Collectively, the findings in the present study suggest that quercetin inhibits VEGF-induced choroidal and retinal angiogenesis by targeting the VEGFR-2 pathway. This suggests that quercetin is a choroidal and retinal angiogenesis inhibitor.

Semaphorin 3A blocks the formation of pathologic choroidal neovascularization induced by transforming growth factor beta.

OBJECTIVE: Choroidal neovascularization (CNV) is a major cause of vision loss in retinal diseases such as age-related macular degeneration (AMD). Previously, we demonstrated that semaphorin3A (Sema3A), which is a chemorepellent guidance molecule, inhibited the formation of retina neovascularization. In the present study, we investigated the antiangiogenic effects of Sema3A on transforming growth factor beta (TGF-ß) in vitro and in vivo. METHODS: Enzyme-linked immunosorbent assays (ELISAs) were used to measure the TGF-ß levels in the vitreous humor of patients with AMD and controls. Human umbilical vein endothelial cells (HUVECs) were used for the in vitro study, and a laser-induced CNV mouse model was prepared for the in vivo study. The HUVECs were incubated with TGF-ß and Sema3A. The proliferation, migration, apoptosis, and tube formation of the cells were then measured using BrdU, Transwell, flow cytometry, and Matrigel assays, respectively, and the SMAD2/3 signaling pathways were analyzed using western blot analysis. The C57BL/6J mouse retina was exposed to a laser to induce choroidal neovascularization (CNV), and Sema3A was injected intravitreously. After 14 days, fundus fluorescein angiography was performed to evaluate the leakage area of the CNV. The vascular endothelial growth factor (VEGF) and TGF-ß concentrations in the retina-choroid complex were measured with ELISA. Components of the p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase-1/2 (ERK1/2), c-Jun NH2-terminal kinase (JNK), and SMAD2/3 signaling pathways in the Sema3A-treated groups were analyzed using western blotting. RESULTS: In this study, we first verified that the vitreous TGF-ß level was higher in patients with neovascular AMD than in the controls. We also showed that Sema3A inhibited TGF-ß-induced HUVEC proliferation, migration, and tube formation and inhibited the downstream SMAD2/3 signaling pathway. Sema3A also induced TGF-ß-stimulated HUVEC apoptosis and inhibited the response of TGF-ß in vitro. In vivo, the TGF-ß level was increased in the CNV mouse model. Sema3A not only inhibited laser-induced CNV formation but also inhibited the uptake of VEGF and TGF-ß. In the western blot analysis, Sema3A was shown to inhibit the phosphorylation of p38 MAPK, ERK1/2, and JNK and to inhibit the SMAD2/3 signaling pathway after Sema3A treatment in CNV mice. CONCLUSIONS: Sema3A can be applied as a useful, adjunctive therapeutic strategy for preventing CNV formation.

Identification of proteins that interact with alpha A-crystallin using a human proteome microarray.

PURPOSE: To identify proteins interacting with alpha A-crystallin (CRYAA) and to investigate the potential role that these protein interactions play in the function of CRYAA using a human proteome (HuProt) microarray. METHODS: The active full-length CRYAA protein corresponding to amino acids 1-173 of CRYAA was recombined. A HuProt microarray composed of 17,225 human full-length proteins with N-terminal glutathione S-transferase (GST) tags was used to identify protein-protein interactions. The probes were considered detectable when the signal to noise ratio (SNR) was over 1.2. The identified proteins were subjected to subsequent bioinformatics analysis using the DAVID database. RESULTS: The HuProt microarray results showed that the signals of 343 proteins were higher in the recombinant CRYAA group than in the control group. The SNR of 127 proteins was ≥ 1.2. The SNR of the following eight proteins was > 3.0: hematopoietic cell-specific Lyn substrate 1 (HCLS1), Kelch domain-containing 6 (KLHDC6), sarcoglycan delta (SGCD), KIAA1706 protein (KIAA1706), RNA guanylyltransferase and 5'-phosphatase (RNGTT), chromosome 10 open reading frame 57 (C10orf57), chromosome 9 open reading frame 52 (C9orf52), and plasminogen activator, urokinase receptor (PLAUR). The bioinformatics analysis revealed 127 proteins associated with phosphoproteins, alternative splicing, acetylation, DNA binding, the nuclear lumen, ribonucleotide binding, the cell cycle, WD40 repeats, protein transport, transcription factor activity, GTP binding, and cellular response to stress. Functional annotation clustering showed that they belong to cell cycle, organelle or nuclear lumen, protein transport, and DNA binding and repair clusters. CRYAA interacted with these proteins to maintain their solubility and decrease the accumulation of denatured target proteins. The protein-protein interactions may help CRYAA carry out multifaceted functions. CONCLUSIONS: One-hundred and twenty-seven of 17,225 human full-length proteins were identified that interact with CRYAA. The advent of microarray analysis enables a better understanding of the functions of CRYAA as a molecular chaperone.