-
The Journal of Physiology Jun 1954
Topics: Humans; Retina; Retinal Pigments
PubMed: 13175197
DOI: 10.1113/jphysiol.1954.sp005127 -
Tissue & Cell Dec 2022To investigate the ameliorative effect of urine-derived stem cells (USCs) conditioned medium on the aging retinal pigment epithelial (RPE) cells and explore the...
OBJECTIVE
To investigate the ameliorative effect of urine-derived stem cells (USCs) conditioned medium on the aging retinal pigment epithelial (RPE) cells and explore the underlying mechanism.
METHODS
The RPE cells were cultured, and aging RPE models were prepared by D-galactose treatment and identified by β-Galactosidase staining. USCs were primarily cultured and identified by immunofluorescence staining. The proliferation and cell cycle of RPE cells in USCs conditioned medium (with USCs removal) were detected by CCK-8 assay and flow cytometry. Gene sequencing was applied to analyze the genetic variation with or without medium treatment. Bioinformatics analysis was used to investigate the biological functions of up- and downregulated differentially expressed genes after medium treatment.
RESULTS
The cell morphology of aging RPE cells treated with the USCs medium were improved significantly and resembled normal RPE cells. In addition, the number of RPE cells increased with USCs medium, and the number of aging cells was significantly reduced after treatment with USCs medium. Moreover, the apoptosis rate of RPE cells was much lower in USCs medium group. The proportion of G1-phase RPE cells was significantly smaller and the proportion of S-phase RPE cells was significantly higher in the USCs medium group. It was found that there were 423 genes upregulated and 64 genes downregulated between the normal RPE cells and aging RPE cells, and 90 genes upregulated and 75 genes downregulated between the aging RPE cells and aging RPE cells cultured in USCs medium.
CONCLUSIONS
Our data confirmed that the USCs could positively ameliorate the aging progression of RPE cells by regulating multiple gene network.
Topics: Culture Media, Conditioned; Stem Cells; Epithelial Cells; Retinal Pigments; Cells, Cultured; Retinal Pigment Epithelium
PubMed: 36126417
DOI: 10.1016/j.tice.2022.101926 -
Journal of Visualized Experiments : JoVE Apr 2023The daily phagocytosis of photoreceptor outer segments by the retinal pigment epithelium (RPE) contributes to the accumulation of an intracellular aging pigment termed...
The daily phagocytosis of photoreceptor outer segments by the retinal pigment epithelium (RPE) contributes to the accumulation of an intracellular aging pigment termed lipofuscin. The toxicity of lipofuscin is well established in Stargardt's disease, the most common inherited retinal degeneration, but is more controversial in age-related macular degeneration (AMD), the leading cause of irreversible blindness in the developed world. Determining lipofuscin toxicity in humans has been difficult, and animal models of Stargardt's have limited toxicity. Thus, in vitro models that mimic human RPE in vivo are needed to better understand lipofuscin generation, clearance, and toxicity. The majority of cell culture lipofuscin models to date have been in cell lines or have involved feeding RPE a single component of the complex lipofuscin mixture rather than fragments/tips of the entire photoreceptor outer segment, which generates a more complete and physiologic lipofuscin model. Described here is a method to induce the accumulation of lipofuscin-like material (termed undigestible autofluorescence material, or UAM) in highly differentiated primary human pre-natal RPE (hfRPE) and induced pluripotent stem cell (iPSC) derived RPE. UAM accumulated in cultures by repeated feedings of ultraviolet light-treated OS fragments taken up by the RPE via phagocytosis. The key ways that UAM approximates and differs from lipofuscin in vivo are also discussed. Accompanying this model of lipofuscin-like accumulation, imaging methods to distinguish the broad autofluorescence spectrum of UAM granules from concurrent antibody staining are introduced. Finally, to assess the impact of UAM on RPE phagocytosis capacity, a new method for quantifying outer segment fragment/tips uptake and breakdown has been introduced. Termed "Total Consumptive Capacity", this method overcomes potential misinterpretations of RPE phagocytosis capacity inherent in classic outer segment "pulse-chase" assays. The models and techniques introduced here can be used to study lipofuscin generation and clearance pathways and putative toxicity.
Topics: Animals; Humans; Lipofuscin; Retinal Pigments; Phagocytosis; Retinal Pigment Epithelium; Cell Line; Cells, Cultured
PubMed: 37125790
DOI: 10.3791/65242 -
BMC Ophthalmology Oct 2022The retinal pigment epithelium (RPE), a layer of pigmented cells that lies between the neurosensory retina and the underlying choroid, plays a critical role in...
BACKGROUND
The retinal pigment epithelium (RPE), a layer of pigmented cells that lies between the neurosensory retina and the underlying choroid, plays a critical role in maintaining the functional integrity of photoreceptor cells and in mediating communication between the neurosensory retina and choroid. Prior studies have demonstrated neurotrophic effects of select steroids that mitigate the development and progression of retinal degenerative diseases via an array of distinct mechanisms of action.
METHODS
Here, we identified major steroid hormone signaling pathways and their key functional protein constituents controlling steroid hormone signaling, which are potentially involved in the mitigation or propagation of retinal degenerative processes, from human proteome datasets with respect to their relative abundances in the retinal periphery, macula, and fovea.
RESULTS
Androgen, glucocorticoid, and progesterone signaling networks were identified and displayed differential distribution patterns within these three anatomically distinct regions of the choroid-retinal pigment epithelial complex. Classical and non-classical estrogen and mineralocorticoid receptors were not identified.
CONCLUSION
Identified differential distribution patterns suggest both selective susceptibility to chronic neurodegenerative disease processes, as well as potential substrates for drug target discovery and novel drug development focused on steroid signaling pathways in the choroid-RPE.
Topics: Humans; Receptors, Mineralocorticoid; Retinal Pigments; Proteome; Androgens; Glucocorticoids; Neurodegenerative Diseases; Progesterone; Choroid; Retinal Pigment Epithelium; Retina; Retinal Degeneration; Estrogens
PubMed: 36266625
DOI: 10.1186/s12886-022-02585-7 -
Retinal Cases & Brief Reports Sep 2021
Topics: Fluorescein Angiography; Humans; Polyneuropathies; Retinal Dystrophies; Retinal Pigments
PubMed: 34171904
DOI: 10.1097/ICB.0000000000001148 -
Journal of Neuroinflammation Oct 2022Forkhead-Box-Protein P3 (FoxP3) is a transcription factor and marker of regulatory T cells, converting naive T cells into Tregs that can downregulate the effector...
BACKGROUND
Forkhead-Box-Protein P3 (FoxP3) is a transcription factor and marker of regulatory T cells, converting naive T cells into Tregs that can downregulate the effector function of other T cells. We previously detected the expression of FoxP3 in retinal pigment epithelial (RPE) cells, forming the outer blood-retina barrier of the immune privileged eye.
METHODS
We investigated the expression, subcellular localization, and phosphorylation of FoxP3 in RPE cells in vivo and in vitro after treatment with various stressors including age, retinal laser burn, autoimmune inflammation, exposure to cigarette smoke, in addition of IL-1β and mechanical cell monolayer destruction. Eye tissue from humans, mouse models of retinal degeneration and rats, and ARPE-19, a human RPE cell line for in vitro experiments, underwent immunohistochemical, immunofluorescence staining, and PCR or immunoblot analysis to determine the intracellular localization and phosphorylation of FoxP3. Cytokine expression of stressed cultured RPE cells was investigated by multiplex bead analysis. Depletion of the FoxP3 gene was performed with CRISPR/Cas9 editing.
RESULTS
RPE in vivo displayed increased nuclear FoxP3-expression with increases in age and inflammation, long-term exposure of mice to cigarette smoke, or after laser burn injury. The human RPE cell line ARPE-19 constitutively expressed nuclear FoxP3 under non-confluent culture conditions, representing a regulatory phenotype under chronic stress. Confluently grown cells expressed cytosolic FoxP3 that was translocated to the nucleus after treatment with IL-1β to imitate activated macrophages or after mechanical destruction of the monolayer. Moreover, with depletion of FoxP3, but not of a control gene, by CRISPR/Cas9 gene editing decreased stress resistance of RPE cells.
CONCLUSION
Our data suggest that FoxP3 is upregulated by age and under cellular stress and might be important for RPE function.
Topics: Animals; Humans; Mice; Rats; Cells, Cultured; Epithelial Cells; Forkhead Transcription Factors; Inflammation; Macular Degeneration; Retinal Pigment Epithelium; Retinal Pigments; Transcription Factors
PubMed: 36273134
DOI: 10.1186/s12974-022-02620-w -
Ocular Immunology and Inflammation Oct 2023To describe the case of a young adult who developed two episodes of Acute Retinal Pigment Epithelitis (ARPE) in the same eye 7 years apart, describing retinal...
PURPOSE
To describe the case of a young adult who developed two episodes of Acute Retinal Pigment Epithelitis (ARPE) in the same eye 7 years apart, describing retinal morphologic changes using SD-OCT scan.
OBSERVATIONS
ARPE is an acute, self-limiting macular disorder characterized by a stippled dark macular lesion surrounded by a hypopigmented halo under fundus examination, corresponding to a foveal disruption of the outer retinal layers and an hyperreflective lesion under SD-OCT scan. Despite ARPE lesions usually appearing to be situated within the macula, a diffuse involvement of the RPE has been suggested. SD-OCT scan in our patient showed multiple focal lesions involving the whole posterior pole of the affected eye.
CONCLUSIONS AND IMPORTANCE
We report the first case where a diffuse involvement of the RPE in the disease is supported by an OCT finding and the case with the longest period between two recurrent self-limited episodes described so far.
Topics: Humans; Young Adult; Fluorescein Angiography; Retinal Diseases; Retinal Pigment Epithelium; Retinal Pigments; Retinitis; Tomography, Optical Coherence
PubMed: 35901522
DOI: 10.1080/09273948.2022.2093752 -
Experimental Eye Research Oct 2022Age-related macular degeneration (AMD) is one of the most common leading causes of irreversible blindness, and there is no effective treatment for it. It has been...
Age-related macular degeneration (AMD) is one of the most common leading causes of irreversible blindness, and there is no effective treatment for it. It has been reported that aging is the greatest risk factor for AMD, and epithelial-mesenchymal transition (EMT) of retinal pigment epithelium (RPE) cells plays an important role in the pathogenesis of AMD. To clarify the relationship between senescence and EMT in RPE cells, we used the replicative senescence model, HO- and/or Nutlin3a-induced senescence model, and low-density and/or TGF-β-induced EMT model to detect the expression of senescence-, RPE- and EMT-related genes, and assessed the motility of cells by using a scratch wound migration assay. The results showed that replicative senescence of RPE cells was accompanied by increased expression of EMT markers. However, senescent RPE cells themselves did not undergo EMT, as the HOand Nutlin3a treated cells showed no increase in EMT characteristics, including unchanged or decreased expression of EMT markers and decreased motility. Furthermore, conditioned medium (CM) from senescent cells induced EMT in presenescent RPE cells, and EMT accelerated the process of senescence. Importantly, dasatinib plus quercetin, which selectively eliminates senescent cells, inhibited low-density-induced EMT in RPE cells. These findings provide a better understanding of the interconnection between senescence and EMT in RPE cells. Removal of senescent cells by certain methods such as senolytics, might be a promising potential approach to prevent or delay the progression of RPE-EMT-related retinal diseases such as AMD.
Topics: Cellular Senescence; Culture Media, Conditioned; Dasatinib; Epithelial Cells; Epithelial-Mesenchymal Transition; Humans; Hydrogen Peroxide; Macular Degeneration; Quercetin; Retinal Pigment Epithelium; Retinal Pigments; Transforming Growth Factor beta
PubMed: 35926646
DOI: 10.1016/j.exer.2022.109207 -
Visual Neuroscience Sep 2021Retinomotor movements include elongation and contraction of rod and cone photoreceptors, and mass migration of melanin-containing pigment granules (melanosomes) of the...
Retinomotor movements include elongation and contraction of rod and cone photoreceptors, and mass migration of melanin-containing pigment granules (melanosomes) of the retinal pigment epithelium (RPE) within the eyes of fish, frogs, and other lower vertebrates. Eyes of these animals do not contain dilatable pupils; therefore the repositioning of the rods and cones and a moveable curtain of pigment granules serve to modulate light intensity within the eye. RPE from sunfish (Lepomis spp.) can be isolated from the eye and dissociated into single cells, allowing in vitro studies of the cytoskeletal and regulatory mechanisms of organelle movement. Pigment granule aggregation from distal tips of apical projections into the cell body can be triggered by the application of underivatized cAMP, and dispersion is effected by cAMP washout in the presence of dopamine. While the phenomenon of cAMP-dependent pigment granule aggregation in isolated RPE was described many years ago, whether cAMP acts through the canonical cAMP-PKA pathway to stimulate motility has never been demonstrated. Here, we show that pharmacological inhibition of PKA blocks pigment granule aggregation, and microinjection of protein kinase A catalytic subunit triggers pigment granule aggregation. Treatment with a cAMP agonist that activates the Rap GEF, Epac (Effector protein activated by cAMP), had no effect on pigment granule position. Taken together, these results confirm that cAMP activates RPE pigment granule motility by the canonical cAMP-PKA pathway. Isolated RPE cells labeled with antibodies against PKA RIIα and against PKA-phosphorylated serine/threonine amino acids show diffuse, punctate labeling throughout the RPE cell body and apical projections. Immunoblotting of RPE lysates using the anti-PKA substrate antibody demonstrated seven prominent bands; two bands in particular at 27 and 64 kD showed increased levels of phosphorylation in the presence of cAMP, indicating their phosphorylation could contribute to the pigment granule aggregation mechanism.
Topics: Animals; Cyclic AMP-Dependent Protein Kinases; Epithelial Cells; Perciformes; Retinal Pigment Epithelium; Retinal Pigments
PubMed: 34521486
DOI: 10.1017/S0952523821000122 -
Ocular Immunology and Inflammation May 2022We investigated the effects of glutathione trisulfide (GSSSG) on lipopolysaccharide (LPS)-induced inflammatory gene expression in immortalized ARPE-19, and primary human...
We investigated the effects of glutathione trisulfide (GSSSG) on lipopolysaccharide (LPS)-induced inflammatory gene expression in immortalized ARPE-19, and primary human and mouse retinal pigment epithelial (RPE) cells. Sulfane sulfur molecules were significantly increased in GSSSG-treated ARPE-19 cells. GSSSG prevented the LPS-induced upregulation of ()-, and () in ARPE-19/primary RPE cells. Moreover, GSSSG prevented the activation of the nuclear factor-kappa B p65 subunit, and promoted the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) in LPS-treated ARPE-19 cells. ERK1/2 inhibition prevented the GSSSG-mediated inhibition of LPS-induced and upregulation. Additionally, ERK1/2 activation prevented the upregulation of these genes in the absence of GSSSG. Knockdown of or , known as anti-oxidative genes, did not affect the activity of GSSSG in the context of LPS stimulation. These findings suggest that GSSSG attenuates LPS-induced inflammatory gene expression via ERK signaling hyperactivation, independently of the NRF2/HMOX1 pathway.
Topics: Animals; Epithelial Cells; Gene Expression; Glutathione; Humans; Inflammation; Interleukin-6; Lipopolysaccharides; Mice; NF-E2-Related Factor 2; Retinal Pigment Epithelium; Retinal Pigments; Sulfur
PubMed: 33215957
DOI: 10.1080/09273948.2020.1833224