scholarly journals TRPM7 ameliorates the blue light-induced apoptosis of RPE cells involving PKC/ERK

2020 ◽  
Author(s):  
Luping Hu ◽  
Guoxing Xu
Keyword(s):  
Blue Light ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Protective Role ◽  
Brdu Incorporation ◽  
Mrna Levels ◽  
Sprague Dawley ◽  
Rpe Cells ◽  
Expression Levels

Abstract Background Blue light triggers apoptosis of retinal pigment epithelium (RPE) cells and causes retinal damage. The aim of this study was to elucidate the protective role of TRPM7 in photo-damaged RPE cells. Methods RPE cells isolated from Sprague-Dawley (SD) rats were cultured in vitro , and exposed to varying intensities of blue light (500-5000 Lux). Cell proliferation and viability were respectively assessed by BrdU incorporation and MTT assays. Real-time PCR and Western blotting were used to analyze the mRNA and protein expression levels of TRPM7, PKC, ERK and Bax/Bcl-2. The cells were transfected with TRPM7 siRNA to knockdown its mRNA levels, or transduced with TRPM7–overexpressing lentiviruses. Pigment epithelium-derived factor (PEDF) was used in combination to detect the anti apoptosis effect. Results Blue light inhibited the proliferation and viability of RPE cells in an intensity-de pendent manner when compared to non-irradiated controls ( P <0.05). Compared to the control, photo-damaged RPE cells showed decreased levels of TRPM7, PKC, ERK and Bax, increased in Bcl-2 ( P <0.01) . Forced expression of TRPM7 partially ameliorated the reduction of proliferation and viability of RPE cells( P <0.01), alleviated the downregulation of TRPM7, PKC, ERK and Bax expression levels( P <0.01), induced by blue light irradiation, while TRPM7 knockdown had opposite effects( P <0.01). TRPM7 and PEDF synergistically alleviated the damaging effects of blue light. Conclusions The apoptosis of RPE cells induced by blue light was positively correlated with the expression of TRPM7. Forced expression of TRPM7 partially attenuated the deleterious effects of blue-light-demaged RPE cells and showed a synergistic protective effect with PEDF, involving PKC/ERK signaling pathway.

scholarly journals Effects of Lycium barbarum polysaccharide on the photoinduced autophagy of retinal pigment epithelium cells

2022 ◽  
Vol 15 (1) ◽  
pp. 23-30
Author(s):  
Yuan-Yuan Gao ◽  
◽  
Jie Huang ◽  
Wu-Jun Li ◽  
Yang Yu ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Cell Counting ◽  
High Dose ◽  
Lycium Barbarum ◽  
Rpe Cells ◽  
Expression Levels ◽  
Lycium Barbarum Polysaccharide

AIM: To investigate the relationship between autophagy and apoptosis in photoinduced injuries in retinal pigment epithelium (RPE) cells and how Lycium barbarum polysaccharide (LBP) contributes to the increased of RPE cells to photoinduced autophagy. METHODS: In vitro cultures of human RPE strains (ARPE-19) were prepared and randomly divided into the blank control, model, low-dose LBP, middle-dose LBP, high-dose LBP, and 3-methyladenine (3MA) groups. The viability of the RPE cells and apoptosis levels in each group were tested through cell counting kit-8 (CCK8) method with a flow cytometer (Annexin V/PI double staining technique). The expression levels of LC3II, LC3I, and P62 proteins were detected with the immunofluorescence method. The expression levels of beclin1, LC3, P62, PI3K, P-mTOR, mTOR, P-Akt, and Akt proteins were tested through Western blot. RESULTS: LBP considerably strengthens cell viability and inhibits the apoptosis of RPE cells after photoinduction. The PI3K/Akt/mTOR signal pathway is activated because of the upregulation of the phosphorylation levels of Akt and mTOR proteins, and thus autophagy is inhibited. CONCLUSION: LBP can inhibit the excessive autophagy in RPE cells by activating the PI3K/Akt/mTOR signaling pathways and thereby protect RPE cells from photoinduced injuries.

The cytoskeletal elements of human retinal pigment epithelium: in vitro and in vivo

1988 ◽  
Vol 91 (2) ◽  
pp. 303-312
Author(s):  
N.M. McKechnie ◽  
M. Boulton ◽  
H.L. Robey ◽  
F.J. Savage ◽  
I. Grierson
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Cytokeratin 18 ◽  
Rpe Cells ◽  
Human Retinal Pigment Epithelium ◽  
Cytoskeletal Elements

The cytoskeletal elements of normal (in situ) and cultured human retinal pigment epithelium (RPE) were studied by a variety of immunocytochemical techniques. Primary antibodies to vimentin and cytokeratins were used. Positive immunoreactivity for vimentin was obtained with in situ and cultured material. The pattern of reactivity obtained with antisera and monoclonals to cytokeratins was more complex. Cytokeratin immunoreactivity could be demonstrated in situ and in cultured cells. The pattern of cytokeratin expression was similar to that of simple or glandular epithelia. A monoclonal antibody that specifically recognizes cytokeratin 18 identified a population of cultured RPE cells that had particularly well-defined filamentous networks within their cytoplasm. Freshly isolated RPE was cytokeratin 18 negative by immunofluorescence, but upon culture cytokeratin 18 positive cells were identifiable. Cytokeratin 18 positive cells were identified in all RPE cultures (other than early primaries), regardless of passage number, age or sex of the donor. In post-confluent cultures cytokeratin 18 cells were identified growing over cytokeratin 18 negative cells, suggesting an association of cytokeratin 18 immunoreactivity with cell proliferation. Immunofluorescence studies of retinal scar tissue from two individuals revealed the presence of numerous cytokeratin 18 positive cells. These findings indicate that RPE cells can be identified by their cytokeratin immunoreactivity and that the overt expression of cytokeratin 18 may be associated with proliferation of human RPE both in vitro and in vivo.

JAM-C maintains VEGR2 expression to promote retinal pigment epithelium cell survival under oxidative stress

2017 ◽  
Vol 117 (04) ◽  
pp. 750-757
Author(s):  
Xin Jia ◽  
Chen Zhao ◽  
Qishan Chen ◽  
Yuxiang Du ◽  
Lijuan Huang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Retinal Pigment Epithelium ◽  
Cell Survival ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Retinal Pigment Epithelium Cell ◽  
Photoreceptor Cells ◽  
Rpe Cells

SummaryJunctional adhesion molecule-C (JAM-C) has been shown to play critical roles during development and in immune responses. However, its role in adult eyes under oxidative stress remains poorly understood. Here, we report that JAM-C is abundantly expressed in adult mouse retinae and choroids in vivo and in cultured retinal pigment epithelium (RPE) and photoreceptor cells in vitro. Importantly, both JAM-C expression and its membrane localisation are downregulated by H2O2-induced oxidative stress. Under H2O2-induced oxidative stress, JAM-C is critically required for the survival of human RPE cells. Indeed, loss of JAM-C by siRNA knockdown decreased RPE cell survival. Mechanistically, we show that JAM-C is required to maintain VEGFR2 expression in RPE cells, and VEGFR2 plays an important role in keeping the RPE cells viable since overexpression of VEGFR2 partially restored impaired RPE survival caused by JAM-C knockdown and increased RPE survival. We further show that JAM-C regulates VEGFR2 expression and, in turn, modulates p38 phosphorylation. Together, our data demonstrate that JAM-C plays an important role in maintaining VEGR2 expression to promote RPE cell survival under oxidative stress. Given the vital importance of RPE in the eye, approaches that can modulate JAM-C expression may have therapeutic values in treating diseases with impaired RPE survival.

scholarly journals A Higher Proportion of Eicosapentaenoic Acid (EPA) When Combined with Docosahexaenoic Acid (DHA) in Omega-3 Dietary Supplements Provides Higher Antioxidant Effects in Human Retinal Cells

Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 828 ◽  
Author(s):  
Manuel Saenz de Viteri ◽  
María Hernandez ◽  
Valentina Bilbao-Malavé ◽  
Patricia Fernandez-Robredo ◽  
Jorge González-Zamora ◽  
...  
Keyword(s):  
Docosahexaenoic Acid ◽  
Eicosapentaenoic Acid ◽  
Cell Viability ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Ethyl Esters ◽  
Omega 3 ◽  
Rpe Cells ◽  
Antioxidant Effects

Retinal pigment epithelium (RPE) is a key regulator of retinal function and is directly related to the transport, delivery, and metabolism of long-chain n-3 polyunsaturated fatty acids (n3-PUFA), in the retina. Due to their functions and location, RPE cells are constantly exposed to oxidative stress. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have shown to have antioxidant effects by different mechanisms. For this reason, we designed an in vitro study to compare 10 formulations of DHA and EPA supplements from different origins and combined in different proportions, evaluating their effect on cell viability, cell proliferation, reactive oxygen species production, and cell migration using ARPE-19 cells. Furthermore, we assessed their ability to rescue RPE cells from the oxidative conditions seen in diabetic retinopathy. Our results showed that the different formulations of n3-PUFAs have a beneficial effect on cell viability and proliferation and are able to restore oxidative induced RPE damage. We observed that the n3-PUFA provided different results alone or combined in the same supplement. When combined, the best results were obtained in formulations that included a higher proportion of EPA than DHA. Moreover, n3-PUFA in the form of ethyl-esters had a worse performance when compared with triglycerides or phospholipid based formulations.

scholarly journals Nanoscopic Approach to Study the Early Stages of Epithelial to Mesenchymal Transition (EMT) of Human Retinal Pigment Epithelial (RPE) Cells In Vitro

Life ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 128
Author(s):  
Lilia A. Chtcheglova ◽  
Andreas Ohlmann ◽  
Danila Boytsov ◽  
Peter Hinterdorfer ◽  
Siegfried G. Priglinger ◽  
...  
Keyword(s):  
Structural Changes ◽  
Epithelial To Mesenchymal Transition ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Cell Phenotype ◽  
Cytoskeletal Reorganization ◽  
Mesenchymal Transition ◽  
Rpe Cells ◽  
Early Stages

The maintenance of visual function is supported by the proper functioning of the retinal pigment epithelium (RPE), representing a mosaic of polarized cuboidal postmitotic cells. Damage factors such as inflammation, aging, or injury can initiate the migration and proliferation of RPE cells, whereas they undergo a pseudo-metastatic transformation or an epithelial to mesenchymal transition (EMT) from cuboidal epithelioid into fibroblast-like or macrophage-like cells. This process is recognized as a key feature in several severe ocular pathologies, and is mimicked by placing RPE cells in culture, which provides a reasonable and well-characterized in vitro model for a type 2 EMT. The most obvious characteristic of EMT is the cell phenotype switching, accompanied by the cytoskeletal reorganization with changes in size, shape, and geometry. Atomic force microscopy (AFM) has the salient ability to label-free explore these characteristics. Based on our AFM results supported by the genetic analysis of specific RPE differentiation markers, we elucidate a scheme for gradual transformation from the cobblestone to fibroblast-like phenotype. Structural changes in the actin cytoskeletal reorganization at the early stages of EMT lead to the development of characteristic geodomes, a finding that may reflect an increased propensity of RPE cells to undergo further EMT and thus become of diagnostic significance.

scholarly journals Expression of Pro-Angiogenic Markers Is Enhanced by Blue Light in Human RPE Cells

Antioxidants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1154 ◽  
Author(s):  
Concetta Scimone ◽  
Simona Alibrandi ◽  
Sergio Zaccaria Scalinci ◽  
Edoardo Trovato Battagliola ◽  
Rosalia D’Angelo ◽  
...  
Keyword(s):  
Blue Light ◽  
Vision Loss ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
R Package ◽  
Rpe Cells ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
Increased Risk ◽  
Angiogenic Markers

Inherited retinal dystrophies are characterized by photoreceptor death. Oxidative stress usually occurs, increasing vision loss, and oxidative damage is often reported in retinitis pigmentosa (RP). More than 300 genes have been reported as RP causing. In contrast, choroidal neovascularization (CNV) only occasionally develops in the late stages of RP. We herein study the regulation of RP causative genes that are likely linked to CNV onset under oxidative conditions. We studied how the endogenous adduct N-retinylidene-N-retinylethanolamine (A2E) affects the expression of angiogenic markers in human retinal pigment epithelium (H-RPE) cells and a possible correlation with RP-causing genes. H-RPE cells were exposed to A2E and blue light for 3 and 6h. By transcriptome analysis, genes differentially expressed between A2E-treated cells and untreated ones were detected. The quantification of differential gene expression was performed by the Limma R package. Enrichment pathway analysis by the FunRich tool and gene prioritization by ToppGene allowed us to identify dysregulated genes involved in angiogenesis and linked to RP development. Two RP causative genes, AHR and ROM1, can be associated with an increased risk of CNV development. Genetic analysis of RP patients affected by CNV will confirm this hypothesis.

scholarly journals Reduction of lipid accumulation rescues Bietti’s crystalline dystrophy phenotypes

2018 ◽  
Vol 115 (15) ◽  
pp. 3936-3941 ◽  
Author(s):  
Masayuki Hata ◽  
Hanako O. Ikeda ◽  
Sachiko Iwai ◽  
Yuto Iida ◽  
Norimoto Gotoh ◽  
...  
Keyword(s):  
Free Cholesterol ◽  
Cell Damage ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Patient Specific ◽  
Rpe Cells ◽  
Underlying Mechanisms ◽  
Induced Pluripotent ◽  
Bietti's Crystalline Dystrophy

Bietti’s crystalline dystrophy (BCD) is an intractable and progressive chorioretinal degenerative disease caused by mutations in the CYP4V2 gene, resulting in blindness in most patients. Although we and others have shown that retinal pigment epithelium (RPE) cells are primarily impaired in patients with BCD, the underlying mechanisms of RPE cell damage are still unclear because we lack access to appropriate disease models and to lesion-affected cells from patients with BCD. Here, we generated human RPE cells from induced pluripotent stem cells (iPSCs) derived from patients with BCD carrying a CYP4V2 mutation and successfully established an in vitro model of BCD, i.e., BCD patient-specific iPSC-RPE cells. In this model, RPE cells showed degenerative changes of vacuolated cytoplasm similar to those in postmortem specimens from patients with BCD. BCD iPSC-RPE cells exhibited lysosomal dysfunction and impairment of autophagy flux, followed by cell death. Lipidomic analyses revealed the accumulation of glucosylceramide and free cholesterol in BCD-affected cells. Notably, we found that reducing free cholesterol by cyclodextrins or δ-tocopherol in RPE cells rescued BCD phenotypes, whereas glucosylceramide reduction did not affect the BCD phenotype. Our data provide evidence that reducing intracellular free cholesterol may have therapeutic efficacy in patients with BCD.

scholarly journals Fallopia Japonica and Prunella Vulgaris Inhibit Myopia Progression by Suppressing Akt and NFκB Mediated Inflammatory Reactions

2021 ◽  
Author(s):  
Chia-Hung Lin ◽  
Chih-Sheng Chen ◽  
Yao-Chien Wang ◽  
En-Shyh Lin ◽  
Ching-Yao Chang ◽  
...  
Keyword(s):  
Transforming Growth Factor Beta ◽  
Axial Length ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Retinal Pigment Epithelial Cell ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Myopia Progression ◽  
Rpe Cells ◽  
Expression Levels

The increased global incidence of myopia requires the establishment of therapeutic approaches. Previous studies have suggested that inflammation plays an important role in the development and progression of myopia. We used human retinal pigment epithelial cell to study the molecular mechanisms on how FJE and PVE lowering the inflammation of the eye. The effect of FJE and PVE in MFD induced hamster model and explore the role of inflammation cytokines in myopia. Expression levels of IL-6, IL-8, and TNF-&alpha; were upregulated in retinal pigment epithelium (RPE) cells treated with IL-6 and TNF-&alpha;. FJ extract (FJE) + PV extract (PVE) reduced IL-6, IL-8, and TNF-&alpha; expression in RPE cells. Furthermore, FJE and PVE inhibited inflammation by attenuating the phosphorylation of protein kinase B (AKT), and nuclear factor kappa-light-chain-enhancer of activated B (NF-&kappa;B) pathway. In addition, we report two resveratrol + ursolic acid compounds from FJ and PV and their inhibitory activities against IL-6, IL-8, and TNF-&alpha; expression levels in RPE cells treated with IL-6 and TNF-&alpha;. FJE, PVE, and FJE + PVE were applied to MFD hamsters and their axial length was measured after 21 days. The axial length showed statistically significant differences between phosphate-buffered saline- and FJE-, PVE-, and FJE + PVE-treated MFD eyes. FJE + PVE suppressed expressions of IL-6, IL-8, and TNF-&alpha;. They also inhibited myopia-related transforming growth factor-beta (TGF)-&beta;1, matrix metalloproteinase (MMP)-2, and NF-&kappa;B expression while increasing type Ⅰ collagen expression. Overall, these results suggest that FJE + PVE may have a therapeutic effect on myopia and be used as a potential treatment option.

scholarly journals Fucoxanthin Pretreatment Ameliorates Visible Light-Induced Phagocytosis Disruption of RPE Cells under a Lipid-Rich Environment via the Nrf2 Pathway

Marine Drugs ◽  
2021 ◽  
Vol 20 (1) ◽  
pp. 15
Author(s):  
Yunjun Liu ◽  
Zixin Guo ◽  
Shengnan Wang ◽  
Yixiang Liu ◽  
Ying Wei
Keyword(s):  
Oxidative Stress ◽  
Visible Light ◽  
Signaling Pathway ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Rpe Cells ◽  
Retinal Injury ◽  
Nrf2 Signaling Pathway ◽  
Ameliorative Effect

Fucoxanthin, a special xanthophyll derived from marine algae, has increasingly attracted attention due to its diverse biological functions. However, reports on its ocular benefits are still limited. In this work, the ameliorative effect of fucoxanthin on visible light and lipid peroxidation-induced phagocytosis disruption in retinal pigment epithelium (RPE) cells was investigated in vitro. Marked oxidative stress, inflammation, and phagocytosis disruption were evident in differentiated RPE cells following their exposure to visible light under a docosahexaenoic acid (DHA)-rich environment. Following pretreatment with fucoxanthin, however, the activated nuclear factor erythroid-derived-2-like 2 (Nrf2) signaling pathway was observed and, furthermore, when the fucoxanthin -pretreated RPE cells were irradiated with visible light, intracellular reactive oxygen species (ROS), malondialdehyde (MDA) levels and inflammation were obviously suppressed, while phagocytosis was significantly improved. However, following the addition of Nrf2 inhibitor ML385, the fucoxanthin exhibited no ameliorative effects on the oxidative stress, inflammation, and phagocytosis disruption in the RPE cells, thus indicating that the ameliorative effect of fucoxanthin on the phagocytosis of RPE cells is closely related to the Nrf2 signaling pathway. In conclusion, these results suggest that fucoxanthin supplementation might be beneficial to the prevention of visible light-induced retinal injury.

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