Torpedo maculopathy is a rare, congenital lesion of RPE, which locates temporal to the macula and along the horizontal raphe. The lesion is torpedo-shaped with its torpedo-like tip pointing towards the fovea. As an incidental finding, it often affects only one eye with no damage to central visual acuity. According to its characteristics on OCT, it is divided into 2 types: typeⅠ, attenuation of outer retinal structures without outer retinal cavitation; typeⅡ, those with both attenuation of outer retinal structures and outer retinal cavitation. Diseases with pigment changes in the RPE layer similar to torpedo maculopathy include congenital hypertrophy of the RPE, RPE lesions in Gardner syndrome, etc. The main point to distinguish the disease from other diseases is its unique location and shape. Most of the torpedo maculopathy lesions are stable and do not require special treatment, but the disease can be complicated by neurosensory retinal detachment, choroidal neovascularization and so on, and symptomatic treatment is needed if necessary.
Severely coagulated retinae by argon laser of 20 Chinese hamsters were investigated with transmission electron-microscopy. The results revealed destruction of retinal pigment epithelium-Bruch's membrane-choroid capillary complex at the coagulated foci, and leakage of fluid and blood cells through the choroidal vessels into the subretinal space. Several days after laser burn the subretinal fluid was found to subside and the RPE cells surrounding the burned lesions started to proliferate. The smaller lesions were covered by the proliferating RPE 10 days after coagulation, but poor regeneration of RPE in large necrotic areas. Neovascularization was usually associated with obvious defect of Bruch's membrane and restoration of RPE barrier was most likely impossible. （Chin J Ocul Fundus Dis,1992,8:14-16）
Objective To observe the inhibition of SARS-CoV-2 spike protein (S-protein) on the proliferation of human retinal pigment epithelium (RPE) cells. MethodsSARS-CoV-2 S-protein gene fragment expression plasmid (p3xflag-S) was constructed and transfected into human RPE, HEK293 cells. DNA sequencing was used for identification, and the expression of Flag-S was detected by Western blot. HEK293 cells were divided into the cells 1, 2, 3 and 4 and transfected with GFP11 plasmid and vector, GFP1-10plasmid and vector, transfected with GFP11 and pCMV-HA-ACE2 plasmid, GFP1-10 and p3xflag-S plasmid. Cell 1 was co-cultured with cell 2 (control group 1), cell 2 with cell 3 (control group 2), cell 3 with cell 4 (observation group), and cell 1 mixed with cells 2, 3 and 4 (control group 3). Bright-field microscopy and fluorescence microscopy were used to observe cell fusion. RPE cells were divided into control group and overexpression S-protein group. The cell cycle was detected by flow cytometry; the cell proliferation level was detected by Counting Kit 8 (CCK-8); and the S-protein expression level in RPE cells was detected by Western blot. The Student’s t-test was performed for comparison between groups. ResultsDNA sequence assay showed that S-protein cDNA was fused with flag-tagged protein. Western blot assay showed thatS-protein-related expression was elevated in transfected HEK293 cells compared with untransfected p3xflag-S cells. Large, multinucleated fused cell clusters were visible under bright-field microscopy; multiple nuclear with distinct green fluorescence were visible in the fused cells under fluorescence microscopy. Western blot assay showed elevated S-protein-related expression in transfected p3xflag-S plasmid RPE cells compared to untransfected p3xflag-S plasmid RPE cells. CCK-8 results showed that the proliferative capacity of RPE cells in the S-protein overexpression group was significantly reduced compared with the control group, with statistically significant differences (t=22.70, 16.75, 23.38; P<0.000 1). The results of flow cytometry showed that the G1 phase cells in the control and overexpression S-protein groups were 41.1% and 67.0%, respectively; compared with the control group, the G1 phase cells in the overexpression S-protein group were significantly higher, and the difference was statistically significant (t=4.76, P=0.018). The apoptosis rate was significantly increased in the S-protein overexpression group compared with the control group, and the difference was statistically significant (t=4.91, P=0.008). ConclusionOverexpression of the SARS-CoV-2 spike protein reduced the proliferation of human RPE cells.
ObjectiveTo observe the effect of TGF-β receptor inhibitor Compound C on the directed differentiation of human embryonic stem cells (hESC) into retinal pigment epithelial (RPE) cells. MethodsH1 hESC were divided into control group and experimental group. When the hESC reached over confluence, the medium was changed to knockout serum replacement medium without bFGF to induce RPE differentiation. The experimental group was supplemented with 1 μmol/L TGF-β receptor inhibitor Compound C at the first six days of induction. Real-time PCR was carried out to examine the expression of paired-box gene 6 (PAX6), microphthalmia-associated transcription factor (MITF), cellular retinaldehyde blinding protein (CRALBP), and RPE65 in both groups at the 1, 3, 5 weeks of the induction process. hESC-derived RPE (hESC-RPE) cells were isolated mechanically and purified. Real-time PCR, Western blot and immunofluorescence were used to characterize the purified hESC-RPE cells. ResultsPigmented colonies were observed in experimental group at the 4 weeks of the induction process, while no pigmented colony could be detected in the control group. All the purified pigmented cells from experimental group showed polygons morphology. Experimental group showed significantly higher expression of RPE marker genes PAX6, MITF, CRALBP and RPE65 than the control group(P<0.05). Compared with the hESC and ARPE-19 cells line, purified hESC-RPE cells showed much higher expression of PAX6, MITF, CRALBP and RPE65(P<0.05).High expression level of PAX6 and RPE65 proteins were observed in hESC-RPE cells. Immunofluorescence verified the expression of PAX6 and ZO-1 in hESC-RPE cells. ConclusionTGF-β receptor inhibitor Compound C significantly improved the differentiation efficiency of hESC into RPE.
Replacement of diseased retinal pigment epithelium (RPE) cells with healthy RPE cells by transplantation is one option to treat several retinal degenerative diseases including age-related macular degeneration, which are caused by RPE loss and dysfunction. A cellular scaffold as a carrier for transplanted cells, may hold immense promise for facilitating cell migration and promoting the integration of RPE cells into the host environment. Scaffolds can be prepared from a variety of natural and synthetic materials. Strategies, such as surface modification and structure adjustment, can improve the biomimetic properties of the scaffolds, optimize cell attachment and cellular function following transplantation and lay a foundation of clinical application in the future.
ObjectiveTo investigate the impact of L-Phenylalanine on the efficiency of retinal pigment epithelial (RPE) cell derivation from human embryonic stem cells (hESCs) and explore the underlying mechanisms. MethodsH1 hESCs were routinely cultured with mTeSR medium and divided into control and experimental groups. When cells reached over-confluence, spontaneous differentiation was triggered using 10% KSR differentiation medium without bFGF. L-Phenylalanine (0.2 mmol/L) was supplemented in the experimental group from the 3rd week. The expression of RPE markers and Wnt signaling components in the two groups was detected by Real time-RCR, Western blot and Flow cytometry analyses. Purified hESC-RPE cells and PBS were injected into the subretinal space of sodium iodine-induced retinal degeneration rats separately. Retinal function was assessed by ERG 6 weeks after the transplantation. ResultsOn the 7th week, much more pigment cell clumps appeared in the experimental group compared to the control group. Within these areas there were monolayer hexagonal RPE cells full of pigment granules. The experimental group showed significantly higher expression of Pax6, MITF, Tyrosinase, RPE65, Wnt3a, Lef1 and Tcf7 genes than the control group (P < 0.01). Higher expression level of MITF and RPE65 proteins and higher percentage of RPE65 (+) cells (P < 0.01) were detected in the experimental group. 6 weeks after sub-retinal transplantation of hESC-RPE cells, the amplitudes of a-b wave in the transplanted eyes were significantly higher than those in the control eyes (P < 0.01) at the stimulus intensity of 3.0 cd·s/m2. ConclusionsL-Phenylalanine effectively promoted the differentiation of embryonic stem cells into retinal pigment epithelial cells, and its impacts on the Wnt/β-catenin signaling pathway may partially explain the underlying mechanisms. Subretinal transplantation of hESC-RPE remarkably improved the retinal functions of retinal degenerative animal models.
RCBTB1 gene associated hereditary retinopathy is an extremely rare inherited retinal disease (IRD) discovered recently. The mutation of RCBTB1 gene can lead to a variety of IRD clinical phenotypes, such as early retinitis pigmentosa and delayed chorioretinal atrophy. The hereditary mode of RCBTB1 gene associated retinopathy is autosomal recessive. RCBTB1 gene plays an important role in maintaining mitochondrial function and anti-oxidative stress defense mechanism of retinal pigment epithelium cells. In the future, it is necessary to further determine whether there is a genotypic and phenotypic correlation in the age of onset of RCBTB1 gene associated retinopathy or multi-organ involvement, and evaluate the safety and efficacy of adeno-associated virus-mediated RCBTB1 gene replacement therapy in animal models, to explore the feasibility of gene replacement therapy and stem cell therapy.
ObjectiveTo observe the expressions of miR-183 and retinal dehydrogenase 11 (RDH11) in exosomes derived from bone marrow mesenchymal stem cells (BMSC), and to preliminarily explore their targeting relationship and their effects on retinal pigment epithelial (RPE) cells. MethodsBMSC from C57BL/6 (C57) mice were isolated and cultured, and BMSC-derived exosomes were identified. BMSC were divided into blank group, simulation blank control group (mimic-NC group), miR-183 simulation group (miR-183-mimic group). C57 mice and retinal degeneration 10 (rd10) mouse RPE cells were cultured with reference to literature methods. RPE cells from rd10 mice were transfected with BMSC exosomes and co-cultured and divided into control group, exosome group, mimic-NC-exosome group (mimic-NC-exo group), miR-183-mimic-exosome group (miR-183-mimic-exo group). The relative expression levels of miR-183, RDH11 mRNA and protein in C57 mice, rd10 mice and RPE cells in each group were detected by real-time quantitative polymerase chain reaction and western blotting. The targeting relationship between miR-183 and RDH11 was analyzed by bioinformatics website and dual luciferase reporter. Cell counting kit 8 was used to detect the effect of miR-183 on BMSC exosomes on RPE cell proliferation; in situ labeling end labeling method was used to detect RPE cells apoptosis. One-way ANOVA was used to compare multiple groups. ResultsCompared with C57 mouse RPE cells, the relative expression of miR-183 in rd10 mouse RPE cells was down-regulated, and the relative expression of RDH11 mRNA was up-regulated, and the differences were statistically significant (t=5.230, 8.548; P=0.006, 0.001). Compared with the blank group and the mimic-NC group, the relative expression of miR-183 mRNA in the exosomes of the miR-183-mimics group was significantly increased (F=60.130, P＜0.05). After 24 h of co-culture, exosomes entered RPE cells. Compared with the mimic-NC-exo group, the relative expression of miR-183 mRNA in RPE cells in the miR-183-mimic-exo group was significantly increased, the proliferation ability was enhanced (t=7.311, P=0.002), and the number of apoptotic cells was decreased (F=10.949, P=0.012), and the differences were statistically significant (t=4.571, P=0.002). Bioinformatics website and dual-luciferase report confirmed that miR-183 has a targeting relationship with RDH11. Compared with the mimic-NC group, the relative expression of RDH11 mRNA and protein in the exosomes of the miR-183-mimic group was decreased, and the difference was statistically significant (t=5.361, 6.591; P=0.006, 0.003). After co-culture, compared with the control group, there was no significant difference in the relative expression of RDH11 mRNA and protein in RPE cells in the exosome group (t=0.169, 1.134; P=0.874, 0.320); The relative expressions of RDH11 mRNA and protein in RPE cells in -183-mimic-exo group were decreased, and the difference was statistically significant (t=5.554, 5.546; P=0.005, 0.005). ConclusionUp-regulation of BMSC-derived exosomal miR-183 promote the proliferation of RPE cells in vitro by targeting the expression of RDH11 and reduce the number of apoptosis.
ObjectiveTo study how CD73 is shed from the retinal pigment epithelium (RPE) surface.MethodsCD73 shedding was induced by treating RPE with lipopolysaccharides (LPS) and TNF-α. After Phospholipase C (PLC) or pan matrix metalloproteinase (MMP) inhibitors were added, surface amount of CD73 was evaluated by flow cytometry (FACS). Then selective inhibitors or their corresponding siRNAs of MMP-2 and MMP-9 were applied to the treatments of RPE; and their effects on induced CD73 shedding were evaluated by FACS. By site directed mutagenesis, mutations were introduced to Lys547-Phe548 coding sites of CD73 cDNA, which was cloned in a pcDNA mammalian expression vector. Both wt-CD73 and mutated-CD73 were over expressed in CD73-/- RPE and their induced shedding was compared.ResultsLPS and TNF-α induced CD73 shedding from RPE was completely blocked by the addition of pan MMP inhibitor but not PLC inhibitor. Selective MPP-9, but not MMP-2, inhibitor or its siRNA blocked CD73 shedding. In CD73-/- RPE induced CD73 shedding was happened to overexpressed wt-CD73 but not Lys547-Phe548 sites mutant CD73.ConclusionMMP-9 is responsible for shedding CD73 from RPE through hydrolyzing its Lys547 -Phe548 sites.
ObjectiveTo observe the changes of eotaxin-1(CCL11), eotaxin-2(CCL24)and eotaxin-3(CCL26)in ranibizumab treated light-injured human retinal pigment epithelium (RPE) cells ARPE-19 and investigate the effects of vascular endothelial growth factor (VEGF) antagonist to the expressions of eotaxins. MethodsCultured human RPE cells(8th-12th generations)were divided into light-injured group, ranibizumab treated group and normal control group. Cells of the three groups were exposed to the blue light at the intensity of(600±100) Lux for 12 h to establish the light injured model, while cell culture dishes of the normal control group were wrapped with double-layer foil. The cells of ranibizumab treated group were treated with VEGF-A antagonist(ranibizumab)at the final concentration of 0.125 mg/ml for 24 hours directly after the illumination. The mRNA and protein of VEGF-A, eotaxin-1, eotaxin-2, eotaxin-3, NF-κB were determined by Real time-PCR, enzyme-linked immunosorbent assay, Western blot, immunohistochemical staining at 0, 3, 6, 12, 24 hours after light damage. ResultsThe mRNA and protein level of VEGF-A, eotaxin-1, eotaxin-2, eotaxin-3, NF-κB in the light-injuried group increased significantly compared to that in normal control group (P < 0.05). After treating with ranibizumab, the expression of eotaxin-1, eotaxin-2, eotaxin-3, NF-κB were significantly suppressed (P < 0.05). ConclusionThe suppression of over-expression of VEGF in human RPE may down-regulate the expression of eotaxins, via the suppression of NF-κB.