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Experimental Eye Research Apr 2022Age-related macular degeneration (AMD) is a major cause of blindness in elderly. It is characterized by the loss of central vision due to damaged retinal pigment...
Age-related macular degeneration (AMD) is a major cause of blindness in elderly. It is characterized by the loss of central vision due to damaged retinal pigment epithelial (RPE) cells and photoreceptors. Blue Light (BL) exposure was proposed as a risk factor for AMD progression. We undertook this study to determine the effects of BL on the behaviour of RPE cells and their potential mitigation by BL-filtering intraocular lenses (IOL). Human RPE cells were exposed or not to BL, with the absence or presence of either a clear ultraviolet (UV)-filtering IOL (CIOL), or a yellow UV- and BL-filtering IOL (YIOL). Cells were analyzed for their oxidative stress by measuring the levels of reactive oxygen species (ROS), and their viability. BL exposure significantly increased the levels of both total cellular and mitochondrial ROS. While this increase was not affected by placing the CIOL in the BL beam, YIOL decreased the levels of both ROS reservoirs. Increased ROS production was accompanied by increased cell death which was similarly decreased when cells were protected with the YIOL. Pre-treatment of cells with N-acetylcycteine (NAC) abolished the increased cell death, suggesting that the effects of BL on cell viability were mainly due to increased levels of ROS. BL is deleterious to RPE cells due to increased oxidative stress and cell death. These effects were mitigated by filtering these radiations. The use of BL-filtering devices may represent a strategy to reduce these effects on RPE cells and delay the onset of AMD.
Topics: Aged; Epithelial Cells; Humans; Light; Macular Degeneration; Oxidative Stress; Reactive Oxygen Species; Retinal Pigment Epithelium; Retinal Pigments
PubMed: 35134392
DOI: 10.1016/j.exer.2022.108978 -
Documenta Ophthalmologica. Advances in... Oct 2022We studied the conditions under which c-waves of the electroretinogram (ERG), that represent retinal pigment epithelium (RPE) function, were detectable using an...
PURPOSE
We studied the conditions under which c-waves of the electroretinogram (ERG), that represent retinal pigment epithelium (RPE) function, were detectable using an alternating current (AC) amplifier and whether the c-wave recorded using an AC amplifier was useful for evaluating RPE function.
METHODS
We recorded ERG responses in rats to 5 s stimuli under the conditions in which the low-cut frequency and the stimulus luminance were varied. In addition, changes in ERGs were studied after intravenous injection of sodium iodate (SI) to induce RPE degeneration.
RESULTS
The c-wave was detected clearly when the frequency of the low-cut filter was set at 0.01 Hz and light stimulus luminances were ≥ - 1.0 log cd/m. The c-wave was attenuated earlier than other waves (e.g., a-wave and b-wave) after SI administration.
CONCLUSIONS
The c-wave was easily detectable using an AC amplifier with the low-cut filter set at 0.01 Hz. Using the AC amplifier may allow easier c-wave recording, compared with the conventional use of a direct current (DC) amplifier, and could be useful for evaluating RPE function.
Topics: Animals; Electroretinography; Epithelial Cells; Iodates; Rats; Retina; Retinal Pigments
PubMed: 35895211
DOI: 10.1007/s10633-022-09890-y -
Environmental Toxicology and... Sep 2023Environmental exposure to urban particulate matter (UPM) is a serious health concern worldwide. Although several studies have linked UPM to ocular diseases, no study has...
Environmental exposure to urban particulate matter (UPM) is a serious health concern worldwide. Although several studies have linked UPM to ocular diseases, no study has reported effects of UPM exposure on senescence in retinal cells. Therefore, this study aimed to investigate the effects of UPM on senescence and regulatory signaling in human retinal pigment epithelial ARPE-19 cells. Our study demonstrated that UPM significantly promoted senescence, with increased senescence-associated β-galactosidase activity. Moreover, both mRNA and protein levels of senescence markers (p16 and p21) and the senescence-associated secretory phenotype, including IL-1β, matrix metalloproteinase-1, and -3 were upregulated. Notably, UPM increased mitochondrial reactive oxygen species-dependent nuclear factor-kappa B (NF-κB) activation during senescence. In contrast, use of NF-κB inhibitor Bay 11-7082 reduced the level of senescence markers. Taken together, our results provide the first in vitro preliminary evidence that UPM induces senescence by promoting mitochondrial oxidative stress-mediated NF-κB activation in ARPE-19 cells.
Topics: Humans; Particulate Matter; NF-kappa B; Cell Line; Reactive Oxygen Species; Oxidative Stress; Cellular Senescence; Retinal Pigments; Epithelial Cells
PubMed: 37423393
DOI: 10.1016/j.etap.2023.104211 -
BMJ Open Ophthalmology Nov 2022Recent clinical studies suggest that RPE-cell replacement therapy may preserve vision and restore retinal structure in retinal degenerative diseases. New developments...
INTRODUCTION
Recent clinical studies suggest that RPE-cell replacement therapy may preserve vision and restore retinal structure in retinal degenerative diseases. New developments enabled the differentiation of RPE cells from pluripotent stem cells. Scaffold-based methods are being tested in ongoing clinical trials for delivering these cells to the back of the eye. Borrowed materials from donor tissues can be used as cell supports in subretinal transplantation. These biological matrices resemble the extracellular matrix microenvironment of the native tissue. The Descemet's membrane (DM) is an example of high collagen-rich basement membrane (BM). The potential of this tissue in retinal repair remains to be uncovered.
AIMS
To investigate human embryonic stem cell-retinal pigment epithelium (hESC-RPE) cells survival and behaviour on a decellularized DM, which may be of clinical relevance in retinal transplantation.
MATERIALS
DMs were isolated from human donor corneas and treated with thermolysin. The DM surface topology and the efficiency of the denudation method were evaluated by atomic force microscope and histology. hESC-RPE cells were seeded onto the endothelial-side surface of acellular DM in order to determine the potential of the membrane to support hESC-RPE cell culture, alongside maintaining their viability. Integrity of the hESC-RPE monolayer was assessed by measuring transepithelial resistance. RPE-specific gene, protein expression and growth factors secretion were assessed to confirm maturation and functionality of the cells over the new substrate.
RESULTS
Thermolysin treatment did not affect the integrity of the tissue, thus ensuring a reliable method to standardize the preparation of decellularized DM. hESC-RPE cell attachment 6 days post-seeding and proliferation rates over the acellular DM were similar to hESC-RPE cells cultured on tissue culture inserts.On the new matrix, hESC-RPE cells succeeded in forming an intact monolayer with mature tight junctions. The resulting cell graft showed the characteristic RPE morphology. The expression of typical RPE genes, proper protein localization and key growth factor secretion further confirmed the correct RPE phenotype. The viability of the cells was maintained for up to 4 weeks in culture.
CONCLUSION
Acellular DM was shown to be capable of sustaining hESC-RPE cells growth, thus confirming to be potentially a valid alternative to the Bruch's membrane.Further in vivo studies will need to verify if this product can represent a feasible tool to deliver RPE cells in the back of the eye.Our study highlights the possibility of recycling unsuitable corneal tissues, which would otherwise be discarded by the eye banks for clinical application.
Topics: Humans; Human Embryonic Stem Cells; Descemet Membrane; Thermolysin; Retinal Diseases; Epithelial Cells; Retinal Pigments
PubMed: 37282676
DOI: 10.1136/bmjophth-2022-EEBA.21 -
Journal of Bioscience and Bioengineering Aug 2017Human retinal pigment epithelial (RPE) cells at different population doublings (PDs) were cultured for 28 days to examine their phenotypic heterogeneity in a confluent...
Human retinal pigment epithelial (RPE) cells at different population doublings (PDs) were cultured for 28 days to examine their phenotypic heterogeneity in a confluent state. In an early population (PD = 2.8), cells showed a cobblestone-like appearance (type I), which gradually became small and tight, and eventually exhibited dark pigmentation. Some cells showed a dome-like structure (type II), which detached from the culture surface during culture. With increasing PD, the cells showed active migration that caused a shift in phenotype from a single layer of large, flattened cells (type III) to a multiple cell layers (stratified) with flattened, irregularly shaped cells (type IV). Immunostaining of specific RPE markers, ZO-1 and Na/K-ATPase revealed that cells have markedly decreased expressions in a late population (PD = 10.1). RPE phenotypes were classified into four types by measuring the nuclear size and local density. The frequencies of type I cells decreased with increasing PD value, while the frequencies of type III and IV cells increased along with the decrease in type I. The frequencies of type IV cells at PD = 10.1 had increased by 10.3-fold compared with PD = 2.8. From these results, the nuclear size and local density were proposed as indicators for understanding phenotypic heterogeneity of RPE cells in the passaged cell population during cell expansion. It is concluded that the population doubling level is an important factor to affect the transition of RPE phenotype and thereby to modulate the quality of cultured cells.
Topics: Cell Count; Cell Proliferation; Cell Shape; Cells, Cultured; Epithelial Cells; Humans; Phenotype; Pigment Epithelium of Eye; Retinal Pigments
PubMed: 28416211
DOI: 10.1016/j.jbiosc.2017.03.008 -
Graefe's Archive For Clinical and... Sep 2016
Topics: Diabetes Mellitus; Fluorescein Angiography; Fundus Oculi; Humans; Retinal Pigments; Tomography, Optical Coherence
PubMed: 27236575
DOI: 10.1007/s00417-016-3397-8 -
Traffic (Copenhagen, Denmark) Apr 2023The endosomal-lysosomal system is central for cell homeostasis and comprises the functions and dynamics of particular organelles including endosomes, lysosomes and...
The endosomal-lysosomal system is central for cell homeostasis and comprises the functions and dynamics of particular organelles including endosomes, lysosomes and autophagosomes. In previous studies, we found that the cysteinyl leukotriene receptor 1 (CysLTR1) regulates autophagy in the retinal pigment epithelial cell line ARPE-19 under basal cellular conditions. However, the underlying mechanism by which CysLTR1 regulates autophagy is unknown. Thus, in the present study, the effects of CysLTR1 inhibition on the endosomal-lysosomal system are analyzed in detail to identify the role of CysLTR1 in cell homeostasis and autophagy regulation. CysLTR1 inhibition in ARPE-19 cells by Zafirlukast, a CysLTR1 antagonist, depleted the lysosomal pool. Furthermore, CysLTR1 antagonization reduced endocytic capacity and internalization of epidermal growth factor and decreased levels of the transferrin receptor, CD71. Serum starvation abolished the effect of Zafirlukast on the autophagic flux, which identifies the endocytic regulation of serum components by CysLTR1 as an important autophagy-modulating mechanism. The role of CysLTR1 in inflammation and cell stress has been exceedingly studied, but its involvement in the endosomal-lysosomal pathway is largely unknown. This current study provides new insights into basal activity of CysLTR1 on cellular endocytosis and the subsequent impact on downstream processes like autophagy.
Topics: Endosomes; Autophagy; Lysosomes; Epithelial Cells; Retinal Pigments
PubMed: 36704929
DOI: 10.1111/tra.12881 -
Biochimica Et Biophysica Acta. General... Aug 2023Mitochondrial dynamics is a morphological balance between fragmented and elongated shapes, reflecting mitochondrial metabolic status, cellular damage, and mitochondrial...
Mitochondrial dynamics is a morphological balance between fragmented and elongated shapes, reflecting mitochondrial metabolic status, cellular damage, and mitochondrial dysfunction. The anaphylatoxin C5a derived from complement component 5 cleavage, enhances cellular responses involved in pathological stimulation, innate immune responses, and host defense. However, the specific response of C5a and its receptor, C5a receptor (C5aR), in mitochondria is unclear. Here, we tested whether the C5a/C5aR signaling axis affects mitochondrial morphology in human-derived retinal pigment epithelial cell monolayers (ARPE-19). C5aR activation with the C5a polypeptide induced mitochondrial elongation. In contrast, oxidatively stressed cells (HO) responded to C5a with an enhancement of mitochondrial fragmentation and an increase in the number of pyknotic nuclei. C5a/C5aR signaling increased the expression of mitochondrial fusion-related protein, mitofusin-1 (MFN1) and - 2 (MFN2), as well as enhanced optic atrophy-1 (Opa1) cleavage, which are required for mitochondrial fusion events, whereas the mitochondrial fission protein, dynamin-related protein-1 (Drp1), and mitogen-activated protein kinase (MAPK)-dependent extracellular signal-regulated protein kinase (Erk1/2) phosphorylation were not affected. Moreover, C5aR activation increased the frequency of endoplasmic reticulum (ER)-mitochondria contacts. Finally, oxidative stress induced in a single cell within an RPE monolayer (488 nm blue laser spot stimulation) induced a bystander effect of mitochondrial fragmentation in adjacent surrounding cells only in C5a-treated monolayers. These results suggest that C5a/C5aR signaling produced an intermediate state, characterized by increased mitochondrial fusion and ER-mitochondrial contacts, that sensitizes cells to oxidative stress, leading to mitochondrial fragmentation and cell death.
Topics: Humans; Epithelial Cells; Hydrogen Peroxide; Mitochondrial Dynamics; Oxidative Stress; Receptor, Anaphylatoxin C5a; Retinal Pigments
PubMed: 37187450
DOI: 10.1016/j.bbagen.2023.130374 -
Archives of Ophthalmology (Chicago,... Aug 1968
Topics: Adolescent; Adult; Age Factors; Aged; Child; Child, Preschool; Epithelium; Female; Humans; Male; Middle Aged; Retina; Retinal Pigments
PubMed: 5661888
DOI: 10.1001/archopht.1968.00980050216012 -
International Journal of Pharmaceutics Apr 2022Age-related macular degeneration (AMD) is defined as a degenerative, progressive and multifactorial disorder that affects the macula with a complex etiology. The retinal...
Age-related macular degeneration (AMD) is defined as a degenerative, progressive and multifactorial disorder that affects the macula with a complex etiology. The retinal pigment epithelium is a monolayer of cells that has the function to separate the surface of the choroid from the neural retina that is involved in the signal transduction leading to vision. The blood-aqueous barrier and the blood retinal barrier limit the permeation of drugs into the retina and thereby reducing their efficacy. Triamcinolone acetonide (TA) is widely used as anti-inflammatory and immunomodulatory drug that promotes the inhibition of the inflammatory processes. The factors that stimulate or inhibit angiogenesis in AMD create a local balance that is responsible for the growth of sub-retinal neovascularization. In AMD, the main angiogenic stimulus is the vascular endothelial growth factor (VEGF). In this work, nanoemulsions with cationic surfactants (mono- and dicationic DABCO and quinuclidine) were produced to deliver TA, and were found to reduce the production of tumor necrosis factor alpha (TNF-α), which stimulates the choroidal neovascularization development by upregulating the VEGF production, and consequently decreased the VEGF levels. Our results support the potential use of mono- and dicationic DABCO and quinuclidine-based cationic nanoemulsions for the delivery of TA in the treatment of AMD.
Topics: Anti-Inflammatory Agents; Choroidal Neovascularization; Epithelial Cells; Humans; Oxidative Stress; Permeability; Retinal Pigments; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors
PubMed: 35217072
DOI: 10.1016/j.ijpharm.2022.121615