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BioRxiv : the Preprint Server For... Jun 2024Mutations in the ( gene are associated with inherited, non-syndromic vision loss. Here, we used CRISPR/Cas9 to induce truncating -null mutations in to create a disease...
Mutations in the ( gene are associated with inherited, non-syndromic vision loss. Here, we used CRISPR/Cas9 to induce truncating -null mutations in to create a disease model. We then tracked progression of retinal degeneration in these animals from the ages of 6 weeks to 3 years old. We found that retinal degeneration caused by -null is age-dependent and likely involves death or damage to the retinal pigment epithelium (RPE) that precedes photoreceptor degeneration. As -null frogs age, they develop large cellular debris deposits in the subretinal space and outer segment layer which resemble subretinal drusenoid deposits (SDD) in their location, histology, and representation in color fundus photography and optical coherence tomography (OCT). In older frogs, these SDD-like deposits accumulate in size and number, and they are present before retinal degeneration occurs. Evidence for an RPE origin of these deposits includes infiltration of pigment granules into the deposits, thinning of RPE as measured by OCT, and RPE disorganization as measured by histology and OCT. The appearance and accumulation of SDD-like deposits and RPE thinning and disorganization in our animal model suggests an underlying disease mechanism for -null mediated blindness of death and dysfunction of the RPE preceding photoreceptor degeneration, instead of direct effects upon photoreceptor outer segment morphogenesis, as was previously hypothesized.
PubMed: 38895468
DOI: 10.1101/2024.06.03.597229 -
BioRxiv : the Preprint Server For... Jun 2024Hereditary defects in the function of the Kir7.1 in the retinal pigment epithelium are associated with the ocular diseases retinitis pigmentosa, Leber congenital...
Hereditary defects in the function of the Kir7.1 in the retinal pigment epithelium are associated with the ocular diseases retinitis pigmentosa, Leber congenital amaurosis, and snowflake vitreal degeneration. Studies also suggest that Kir7.1 may be regulated by a GPCR, the melanocortin-4 receptor, in certain hypothalamic neurons. We present the first structures of human Kir7.1 and describe the conformational bias displayed by two pathogenic mutations, R162Q and E276A, to provide an explanation for the basis of disease and illuminate the gating pathway. We also demonstrate the structural basis for the blockade of the channel by a small molecule ML418 and demonstrate that channel blockade in vivo activates MC4R neurons in the paraventricular nucleus of the hypothalamus (PVH), inhibiting food intake and inducing weight loss. Preliminary purification, and structural and pharmacological characterization of an in tandem construct of MC4R and Kir7.1 suggests that the fusion protein forms a homotetrameric channel that retains regulation by liganded MC4R molecules.
PubMed: 38895219
DOI: 10.1101/2024.06.07.597981 -
International Journal of Molecular... May 2024In this immunohistological study on the peripheral retina of 3-year-old beagle dogs, excised retina specimens were immunostained with antibodies against nestin, Oct4,...
In this immunohistological study on the peripheral retina of 3-year-old beagle dogs, excised retina specimens were immunostained with antibodies against nestin, Oct4, Nanog, Sox2, CDX2, cytokeratin 18 (CK 18), RPE65, and YAP1, as well as hematoxylin and DAPI, two nuclear stains. Our findings revealed solitary cysts of various sizes in the inner retina. Intriguingly, a mass of small round cells with scant cytoplasms was observed in the cavity of small cysts, while many disorganized cells partially occupied the cavity of the large cysts. The small cysts were strongly positive for nestin, Oct4, Nanog, Sox2, CDX2, CK18, and YAP1. RPE65-positive cells were exclusively observed in the tissue surrounding the cysts. Since RPE65 is a specific marker of retinal pigment epithelial (RPE) cells, the surrounding cells of the peripheral cysts were presumably derived from RPE cells that migrated intraretinally. In the small cysts, intense positive staining for nestin, a marker of retinal stem cells, seemed to indicate that they were derived from retinal stem cells. The morphology and positive staining for markers of blastocyst and RPE cells indicated that the small cysts may have formed structures resembling the blastocyst, possibly caused by the interaction between retinal stem cells and migrated RPE cells.
Topics: Animals; Dogs; Retina; Retinal Pigment Epithelium; Nestin; Blastocyst; Biomarkers; SOXB1 Transcription Factors; Stem Cells; Immunohistochemistry; Dog Diseases
PubMed: 38892233
DOI: 10.3390/ijms25116045 -
International Journal of Molecular... May 2024Sulfated marine polysaccharides, so-called fucoidans, have been shown to exhibit anti-inflammatory and immunomodulatory activities in retinal pigment epithelium (RPE)....
Sulfated marine polysaccharides, so-called fucoidans, have been shown to exhibit anti-inflammatory and immunomodulatory activities in retinal pigment epithelium (RPE). In this study, we tested the effects of different fucoidans (and of fucoidan-treated RPE cells) on retinal microglia to investigate whether its anti-inflammatory effect can be extrapolated to the innate immune cells of the retina. In addition, we tested whether fucoidan treatment influenced the anti-inflammatory effect of RPE cells on retinal microglia. Three fucoidans were tested (FVs from , Fuc1 and FucBB04 from ) as well as the supernatant of primary porcine RPE treated with fucoidans for their effects on inflammatory activated (using lipopolysaccharide, LPS) microglia cell line SIM-A9 and primary porcine retinal microglia. Cell viability was detected with a tetrazolium assay (MTT), and morphology by Coomassie staining. Secretion of tumor necrosis factor alpha (TNFα), interleukin 1 beta (IL1β) and interleukin 8 (IL8) was detected with ELISA, gene expression ( (Nitric oxide synthase 2), and (IL8)) with qPCR. Phagocytosis was detected with a fluorescence assay. FucBB04 and FVs slightly reduced the viability of SIM-A9 and primary microglia, respectively. Treatment with RPE supernatants increased the viability of LPS-treated primary microglia. FVs and FucBB04 reduced the size of LPS-activated primary microglia, indicating an anti-inflammatory phenotype. RPE supernatant reduced the size of LPS-activated SIM-A9 cells. Proinflammatory cytokine secretion and gene expression in SIM-A9, as well as primary microglia, were not significantly affected by fucoidans, but RPE supernatants reduced the secretion of LPS-induced proinflammatory cytokine secretion in SIM-A9 and primary microglia. The phagocytosis ability of primary microglia was reduced by FucBB04. In conclusion, fucoidans exhibited only modest effects on inflammatorily activated microglia by maintaining their cell size under stimulation, while the anti-inflammatory effect of RPE cells on microglia irrespective of fucoidan treatment could be confirmed, stressing the role of RPE in regulating innate immunity in the retina.
Topics: Microglia; Animals; Polysaccharides; Swine; Retinal Pigment Epithelium; Cell Survival; Phagocytosis; Retina; Cell Line; Lipopolysaccharides; Anti-Inflammatory Agents; Cytokines
PubMed: 38892206
DOI: 10.3390/ijms25116018 -
International Journal of Molecular... May 2024Retinitis pigmentosa (RP) is an inherited retinal dystrophy caused by the loss of photoreceptors and retinal pigment epithelial atrophy, leading to severe visual...
Retinitis pigmentosa (RP) is an inherited retinal dystrophy caused by the loss of photoreceptors and retinal pigment epithelial atrophy, leading to severe visual impairment or blindness. RP can be classified as nonsyndromic or syndromic with complex clinical phenotypes. Three unrelated Polish probands affected with retinitis pigmentosa coexisting with cerebellar ataxia were recruited for this study. Clinical heterogeneity and delayed appearance of typical disease symptoms significantly prolonged the patients' diagnostic process. Therefore, many clinical and genetic tests have been performed in the past. Here, we provide detailed clinical and genetic analysis results of the patients. Whole-exome sequencing (WES) and targeted NGS analysis allow the identification of four novel and two previously reported variants in the following genes: , , and The use of next-generation sequencing (NGS) methods finally allowed for confirmation of the clinical diagnosis. Ultra-rare diseases such as PHARC, PCARP, and Oliver-McFarlane syndromes were diagnosed in patients, respectively. Our findings confirmed the importance of the application of next-generation sequencing methods, especially in ultra-rare genetic disorders with overlapping features.
Topics: Humans; Retinitis Pigmentosa; Male; Female; Exome Sequencing; Pedigree; High-Throughput Nucleotide Sequencing; Adult; Cerebellar Ataxia; Membrane Transport Proteins; Monoacylglycerol Lipases; Mutation; Ataxia; Phenotype; Acyltransferases; Cataract; Phospholipases; Polyneuropathies
PubMed: 38891946
DOI: 10.3390/ijms25115759 -
Molecular Neurodegeneration Jun 2024Age-related macular degeneration (AMD) is the leading cause of blindness in elderly people in the developed world, and the number of people affected is expected to...
BACKGROUND
Age-related macular degeneration (AMD) is the leading cause of blindness in elderly people in the developed world, and the number of people affected is expected to almost double by 2040. The retina presents one of the highest metabolic demands in our bodies that is partially or fully fulfilled by mitochondria in the neuroretina and retinal pigment epithelium (RPE), respectively. Together with its post-mitotic status and constant photooxidative damage from incoming light, the retina requires a tightly-regulated housekeeping system that involves autophagy. The natural polyphenol Urolithin A (UA) has shown neuroprotective benefits in several models of aging and age-associated disorders, mostly attributed to its ability to induce mitophagy and mitochondrial biogenesis. Sodium iodate (SI) administration recapitulates the late stages of AMD, including geographic atrophy and photoreceptor cell death.
METHODS
A combination of in vitro, ex vivo and in vivo models were used to test the neuroprotective potential of UA in the SI model. Functional assays (OCT, ERGs), cellular analysis (flow cytometry, qPCR) and fine confocal microscopy (immunohistochemistry, tandem selective autophagy reporters) helped address this question.
RESULTS
UA alleviated neurodegeneration and preserved visual function in SI-treated mice. Simultaneously, we observed severe proteostasis defects upon SI damage induction, including autophagosome accumulation, that were resolved in animals that received UA. Treatment with UA restored autophagic flux and triggered PINK1/Parkin-dependent mitophagy, as previously reported in the literature. Autophagy blockage caused by SI was caused by severe lysosomal membrane permeabilization. While UA did not induce lysosomal biogenesis, it did restore upcycling of permeabilized lysosomes through lysophagy. Knockdown of the lysophagy adaptor SQSTM1/p62 abrogated viability rescue by UA in SI-treated cells, exacerbated lysosomal defects and inhibited lysophagy.
CONCLUSIONS
Collectively, these data highlight a novel putative application of UA in the treatment of AMD whereby it bypasses lysosomal defects by promoting p62-dependent lysophagy to sustain proteostasis.
Topics: Animals; Mice; Coumarins; Autophagy; Macular Degeneration; Retina; Mitophagy; Sequestosome-1 Protein; Lysosomes; Humans; Disease Models, Animal; Neuroprotective Agents; Mice, Inbred C57BL; Iodates
PubMed: 38890703
DOI: 10.1186/s13024-024-00739-3 -
Scientific Reports Jun 2024Age-related macular degeneration (AMD) is one of the major causes of blindness in the elderly worldwide. Anti-vascular endothelial growth factor (VEGF) drugs have been...
Age-related macular degeneration (AMD) is one of the major causes of blindness in the elderly worldwide. Anti-vascular endothelial growth factor (VEGF) drugs have been widely used to treat the neovascular type of AMD (nAMD). However, VEGF acts not only as a pro-angiogenic factor but also as an anti-apoptotic factor in the eyes. In this study, we found that anti-VEGF drugs, including bevacizumab (Bev), ranibizumab (Ran), and aflibercept (Afl), induced epithelial-mesenchymal transition (EMT) in ARPE-19 cells in vitro, accompanied by the induction of CCN2, a potent pro-fibrotic factor. Similarly, intravitreal injection of Afl into mouse eyes resulted in EMT in the retinal pigmented epithelium (RPE). Co-treatment with CCN5, an anti-fibrotic factor that down-regulates CCN2 expression, significantly attenuated the adverse effects of the anti-VEGF drugs both in vitro and in vivo. Inhibition of the VEGF signaling pathway with antagonists of VEGF receptors, SU5416 and ZM323881, induced EMT and up-regulated CCN2 in ARPE-19 cells. Additionally, knock-down of CCN2 with siRNA abolished the adverse effects of the anti-VEGF drugs in ARPE-19 cells. Collectively, these results suggest that anti-VEGF drugs induce EMT in RPE through the induction of CCN2 and that co-treatment with CCN5 attenuates the adverse effects of anti-VEGF drugs in mouse eyes.
Topics: Epithelial-Mesenchymal Transition; Retinal Pigment Epithelium; Animals; Humans; Mice; Vascular Endothelial Growth Factor A; Macular Degeneration; Cell Line; Bevacizumab; CCN Intercellular Signaling Proteins; Angiogenesis Inhibitors; Ranibizumab; Recombinant Fusion Proteins; Signal Transduction; Repressor Proteins; Receptors, Vascular Endothelial Growth Factor
PubMed: 38886213
DOI: 10.1038/s41598-024-63565-z -
Ophthalmology Science 2024Progressive retinal atrophy has been described after subretinal gene therapy utilizing the adeno-associated virus (AAV) vector platform. To elucidate whether this...
OBJECTIVE
Progressive retinal atrophy has been described after subretinal gene therapy utilizing the adeno-associated virus (AAV) vector platform. To elucidate whether this atrophy is a consequence of inherent properties of AAV, or if it is related to the surgical trauma of subretinal delivery, we analyzed data from an Investigational New Drug-enabling study for PDE6A gene therapy in nonhuman primates.
DESIGN
Animal study (nonhuman primates), retrospective data analysis.
SUBJECTS
Forty eyes of 30 healthy nonhuman primates (macaca fascicularis) were included in the analysis. Two AAV dose levels (low: 1x10E11, high: 1x10E12) were compared with sham injection (balanced saline solution; BSS). Twenty untreated eyes were not analyzed.
METHODS
Animals were treated with a sutureless 23G vitrectomy and single subretinal injections of AAV.PDE6A and/or BSS. The follow-up period was 12 weeks. Atrophy development was followed using fundus autofluorescence (AF), OCT, fluorescence angiography, and indocyanine green angiography.
MAIN OUTCOME MEASURES
Area [mm] of retinal pigment epithelium atrophy on AF. Presence of outer retinal atrophy on optical coherence tomography. Area [mm] of hyperfluorescence in fluorescence angiography and hypofluorescence in indocyanine green angiography.
RESULTS
Progressive atrophy at the injection site developed in 54% of high-dose-treated, 27% of low-dose-treated, and 0% of sham-treated eyes. At the end of observation, the mean ± SD area of atrophy in AF was 1.19 ± 1.75 mm, 0.25 ± 0.50 mm, and 0.0 ± 0.0 mm, respectively (sham × high dose: = 0.01). Atrophic lesions in AF ( = 0.01) and fluorescence angiography ( = 0.02) were significantly larger in high-dose-treated eyes, compared with sham-treated eyes. Rate of progression in high-dose-treated eyes was 4.1× higher compared with low-dose-treated eyes.
CONCLUSION
Subretinal injection of AAV.PDE6A induced dose-dependent, progressive retinal atrophy at the site of injection. Findings from multimodal imaging were in line with focal, transient inflammation within the retina and choroid and secondary atrophy. Atrophic changes after gene therapy with AAV-based vector systems are not primarily due to surgical trauma and increase with the dose given.
FINANCIAL DISCLOSURES
Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
PubMed: 38881604
DOI: 10.1016/j.xops.2024.100516 -
Molecular Biology Reports Jun 2024Human Amniotic Membrane (hAM) is endowed with several biological activities and might be considered an optimal tool in surgical treatment for different ophthalmic...
BACKGROUND
Human Amniotic Membrane (hAM) is endowed with several biological activities and might be considered an optimal tool in surgical treatment for different ophthalmic pathologies. We pioneered the surgical use of hAM to treat retinal pathologies such as macular holes, tears, and retinal detachments, and to overcome photoreceptor damage in age-related macular degeneration. Although hAM contributed to improved outcomes, the mechanisms of its effects are not yet fully understood. The characterization and explanation of the effects of hAM would allow the adoption of this new natural product in different retinal pathologies, operative contexts, and hAM formulations. At this end, we studied the properties of a hAM extract (hAME) on the ARPE-19 cells.
METHODS AND RESULTS
A non-denaturing sonication-based technique was developed to obtain a suitable hAME. Viability, proliferation, apoptosis, oxidative stress, and epithelial-mesenchymal transition (EMT) were studied in hAME-treated ARPE-19 cells. The hAME was able to increase ARPE-19 cell viability even in the presence of oxidative stress (HO, TBHP). Moreover, hAME prevented the expression of EMT features, such as EMT-related proteins, fibrotic foci formation, and migration induced by different cytokines.
CONCLUSIONS
Our results demonstrate that the hAME retains most of the properties observed in the whole tissue by others. The hAME, other than providing a manageable research tool, could represent a cost-effective and abundant drug to treat retinal pathologies in the future.
Topics: Humans; Amnion; Cell Line; Retinal Pigment Epithelium; Cell Survival; Apoptosis; Oxidative Stress; Cell Proliferation; Epithelial-Mesenchymal Transition; Tissue Extracts
PubMed: 38874663
DOI: 10.1007/s11033-024-09647-7 -
Scientific Reports Jun 2024This study aims to correlate adaptive optics-transscleral flood illumination (AO-TFI) images of the retinal pigment epithelium (RPE) in central serous chorioretinopathy...
This study aims to correlate adaptive optics-transscleral flood illumination (AO-TFI) images of the retinal pigment epithelium (RPE) in central serous chorioretinopathy (CSCR) with standard clinical images and compare cell morphological features with those of healthy eyes. After stitching 125 AO-TFI images acquired in CSCR eyes (including 6 active CSCR, 15 resolved CSCR, and 3 from healthy contralateral), 24 montages were correlated with blue-autofluorescence, infrared and optical coherence tomography images. All 68 AO-TFI images acquired in pathological areas exhibited significant RPE contrast changes. Among the 52 healthy areas in clinical images, AO-TFI revealed a normal RPE mosaic in 62% of the images and an altered RPE pattern in 38% of the images. Morphological features of the RPE cells were quantified in 54 AO-TFI images depicting clinically normal areas (from 12 CSCR eyes). Comparison with data from 149 AO-TFI images acquired in 33 healthy eyes revealed significantly increased morphological heterogeneity. In CSCR, AO-TFI not only enabled high-resolution imaging of outer retinal alterations, but also revealed RPE abnormalities undetectable by all other imaging modalities. Further studies are required to estimate the prognosis value of these abnormalities. Imaging of the RPE using AO-TFI holds great promise for improving our understanding of the CSCR pathogenesis.
Topics: Humans; Retinal Pigment Epithelium; Central Serous Chorioretinopathy; Male; Female; Middle Aged; Tomography, Optical Coherence; Adult; Fluorescein Angiography; Optical Imaging; Sclera
PubMed: 38871803
DOI: 10.1038/s41598-024-64524-4