Project description:we report the effect of Ramoplanin on the transcription profile of RPE cells in comparison to DMSO (Vehicle) or MFGE8+GAS6 treated cells in the presence and absence of POS
Project description:Retinal photoreceptors undergo daily renewal of their distal outer segments, a process indispensable for maintaining retinal health. Photoreceptor Outer Segment (POS) phagocytosis occurs as a daily peak, roughly about one hour after light onset. However, the underlying cellular and molecular mechanisms which initiate this process are still unknown. Here we show that, under constant darkness, mice deficient for core circadian clock genes (Per1 and Per2), lack a daily peak in POS phagocytosis. By qPCR analysis we found that core clock genes were rhythmic over 24h in both WT and Per1, Per2 double mutant whole retinas. More precise transcriptomics analysis of laser capture microdissected WT photoreceptors revealed no differentially expressed genes between time-points preceding and during the peak of POS phagocytosis. By contrast, we found that microdissected WT retinal pigment epithelium (RPE) had a number of genes that were differentially expressed at the peak phagocytic time-point compared to adjacent ones. We also found a number of differentially expressed genes in Per1, Per2 double mutant RPE compared to WT ones at the peak phagocytic time-point. Finally, based on STRING analysis we found a group of interacting genes which potentially drive POS phagocytosis in the RPE. This potential pathway consists of genes such as: Pacsin1, Syp, Camk2b and Camk2d among others. Our findings indicate that Per1 and Per2 are necessary clock components for driving POS phagocytosis and suggest that this process is transcriptionally driven by the RPE.
Project description:One of the major biological functions accomplished by the retinal pigmented epithelium (RPE) is the clearance of shed photoreceptor outer segments (POS) through a multistep process referred to as phagocytosis. Phagocytosis helps maintain the viability of photoreceptors which otherwise could succumb to the high metabolic flux and photo-oxidative stress associated with visual processing. Regulatory mechanisms underlying phagocytosis in the RPE are not fully understood, although dysfunction of this process contributes to the pathogenesis of multiple human retinal degenerative disorders, including age-related macular degeneration (AMD). Here we present an integrated analysis of phagocytosing cultured-RPE cells.
Project description:Purpose: Primary retinal pigment epithelium (RPE) cells have a limited capacity to re-establish epithelial morphology and to remain native RPE function in vitro, and all commercially available RPE cell lines have drawbacks of morphology or function; therefore, the establishment of new RPE cell lines with typical characteristics of RPE would be helpful in further understanding of their physiological and pathological mechanism. Here, we firstly report a new spontaneously generated RPE line, fhRPE-13A, from a 13-week aborted foetus. We aimed to investigate its availability as a RPE model. Methods:RNA-seq data were mapped to the human genome assembly hg19. Global transcriptional data were analyzed by Weighted Gene Co-expression Network Analysis (WGCNA) and differentially expressed genes(DEGs) to identify gene expression profiles. The morphology and molecular characteristics were examined by immunofluorescence, transmission electron micrographs, PCR and western blot. Photoreceptor outer segments (POS) phagocytosis assay and transepithelial resistance measurement (TER) were performed to assess phagocytic activity and barrier function, respectively. Results: The fhRPE-13A cells showed typical polygonal morphology and the normal biological processes of RPE, had ability of POS phagocytosis in vitro, and expressed TYR and TYRP1 significantly higher than that in ARPE-19 cells. Conclusions: The fetal human RPE line fhRPE-13A is a valuable system for researching phagocytosis function and morphogenesis of RPE in vitro.
Project description:Retinal photoreceptors undergo daily renewal of their distal outer segments, a process indispensable for maintaining retinal health. Photoreceptor Outer Segment (POS) phagocytosis occurs as a daily peak, roughly about one hour after light onset. However, the underlying cellular and molecular mechanisms which initiate this process are still unknown. Here we show that, under constant darkness, mice deficient for core circadian clock genes (Per1 and Per2), lack a daily peak in POS phagocytosis. By qPCR analysis we found that core clock genes were rhythmic over 24h in both WT and Per1, Per2 double mutant whole retinas. More precise transcriptomics analysis of laser capture microdissected WT photoreceptors revealed no differentially expressed genes between time-points preceding and during the peak of POS phagocytosis. By contrast, we found that microdissected WT retinal pigment epithelium (RPE) had a number of genes that were differentially expressed at the peak phagocytic time-point compared to adjacent ones. We also found a number of differentially expressed genes in Per1, Per2 double mutant RPE compared to WT ones at the peak phagocytic time-point. Finally, based on STRING analysis we found a group of interacting genes which potentially drive POS phagocytosis in the RPE. This potential pathway consists of genes such as: Pacsin1, Syp, Camk2b and Camk2d among others. Our findings indicate that Per1 and Per2 are necessary clock components for driving POS phagocytosis and suggest that this process is transcriptionally driven by the RPE.
Project description:One of the major biological functions accomplished by the retinal pigmented epithelium (RPE) is the clearance of shed photoreceptor outer segments (POS) through a multistep process referred to as phagocytosis. Phagocytosis helps maintain the viability of photoreceptors which otherwise could succumb to the high metabolic flux and photo-oxidative stress associated with visual processing. Regulatory mechanisms underlying phagocytosis in the RPE are not fully understood, although dysfunction of this process contributes to the pathogenesis of multiple human retinal degenerative disorders, including age-related macular degeneration (AMD). Here we present an integrated analysis of phagocytosing cultured-RPE cells.
Project description:Retinal pigment epithelium (RPE) cell integrity is critical to the maintenance of retinal function. Many retinopathies such as age-related macular degeneration (AMD) are caused by the degeneration or malfunction of the RPE cell layer. Replacement of diseased RPE with healthy, stem cell derived RPE is a potential therapeutic strategy for treating AMD. Human embryonic stem cells (hESC) differentiated into RPE progeny have potential to provide an unlimited supply of cells for transplantation but challenges around scalability and efficiency of the differentiation process still remain. Using hESC-derived RPE as a cellular model, we sought to understand mechanisms that could be modulated to increase RPE yield following differentiation. Our data show that activation of the cAMP pathway increases proliferation of dissociated RPE in culture, in part through inhibition of TGFβ signalling. This in turn results in enhanced uptake of epithelial identity. In line with these findings, targeted manipulation of the TGFβ pathway with small molecules produces an increase in efficiency of RPE re-epithelialization. Taken together, these data highlight mechanisms that promote epithelial fate acquisition in stem cell derived RPE. Modulation of these pathways has potential to favorably impact upon scalability and clinical translation of hESC-derived RPE as a cell therapy. A sample of Gene Pool™ cDNA, from human fetal normal brain tissue (Invitrogen D8830-01) is included for reference.
Project description:Retinal Pigment Epithelial (RPE) cells are located behind the retina and are critical for photoreceptor survival. Loss of RPE is associated with several pathogenic conditions such as Age Related Macular Degeneration and Retinitis Pigmentosa. RPE derived from human embryonic stem cells (hESC) offer a potential source for producing these cells for therapy. Here we report the molecular and cellular characterization of RPE differentiated from hESC. hESC derived RPE are capable of proliferation and lose their epithelial characteristics before becoming confluent and re-differentiating back into their typical pigmented, cobblestoned appearance. During the proliferative phase, they adopt a mesenchymal morphology and express mesenchymal markers. Our results demonstrate that this apparent Epithelial-Mesenchymal Transition is not regulated by the classical EMT transcription factors SNAIL and SLUG. Furthermore, it is possible to regulate RPE de-differentiation and re-differentiation by modulating the Wnt and BMP pathway respectively. These findings further our understanding of the genesis and expansion of RPE which is essential for their therapeutic use.
Project description:Retinal Pigment Epithelial (RPE) cells are located behind the retina and are critical for photoreceptor survival. Loss of RPE is associated with several pathogenic conditions such as Age Related Macular Degeneration and Retinitis Pigmentosa. RPE derived from human embryonic stem cells (hESC) offer a potential source for producing these cells for therapy. Here we report the molecular and cellular characterization of RPE differentiated from hESC. hESC derived RPE are capable of proliferation and lose their epithelial characteristics before becoming confluent and re-differentiating back into their typical pigmented, cobblestoned appearance. During the proliferative phase, they adopt a mesenchymal morphology and express mesenchymal markers. Our results demonstrate that this apparent Epithelial-Mesenchymal Transition is not regulated by the classical EMT transcription factors SNAIL and SLUG. Furthermore, it is possible to regulate RPE de-differentiation and re-differentiation by modulating the Wnt and BMP pathway respectively. These findings further our understanding of the genesis and expansion of RPE which is essential for their therapeutic use.