scholarly journals Axon Guidance Signaling Modulates Epithelial to Mesenchymal Transition in Stem Cell-Derived Retinal Pigment Epithelium

2018 ◽  
Author(s):  
Srinivas R. Sripathi ◽  
Melissa M. Liu ◽  
Ming-Wen Hu ◽  
Jun Wan ◽  
Jie Cheng ◽  
...  
Keyword(s):  
Stem Cell ◽  
Retinal Pigment Epithelium ◽  
Axon Guidance ◽  
Epithelial To Mesenchymal Transition ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Critical Role ◽  
Age Related Macular Degeneration ◽  
Mesenchymal Transition ◽  
Monolayer Cultures

ABSTRACTThe critical role of epithelial to mesenchymal transition (EMT) in embryonic development, malignant transformation, and tumor progression has been well studied in normal and cancerous tissues and cells. Interestingly, EMT has also been reported to play a key role in the early progression of several retinal degenerative diseases, including scarring associated proliferative vitro-retinopathy (PVR), choroidal neo-vascularization induced “wet” age-related macular degeneration (AMD) and diabetic retinopathy (DR). Despite these studies, many questions remain unexplored regarding EMT-associated retinal pigment epithelium (RPE) degeneration and dysfunction. We hypothesize that RPE cells undergo EMT prior to cell death during the progression of atrophic “dry” AMD. Utilizing human stem cell-derived RPE (hRPE) as a model to study RPE EMT, we optimized two independent but complementary RPE EMT induction systems: 1) enzymatic dissociation of hRPE monolayer cultures and 2) co-treatment of hRPE monolayer cultures with transforming growth factor beta (TGF-β) and the inflammatory cytokine, tumor necrosis factor alpha (TNF-α). To further understand the molecular mechanisms of RPE EMT regulation, we performed an RNA-Sequencing (RNA-Seq) time course examination across 48 hours beginning with EMT induction. Our transcriptome profiling provides a comprehensive quantification of dynamic signaling events and associated biological pathways underlying RPE EMT and reveals an intriguing significance for widespread dysregulation of multiple axon guidance molecules in this process.

scholarly journals Quantitative metabolomics of photoreceptor degeneration and the effects of stem cell-derived retinal pigment epithelium transplantation

2016 ◽  
Vol 374 (2079) ◽  
pp. 20150376 ◽  
Author(s):  
Junhua Wang ◽  
Peter D. Westenskow ◽  
Mingliang Fang ◽  
Martin Friedlander ◽  
Gary Siuzdak
Keyword(s):  
Stem Cell ◽  
Retinal Pigment Epithelium ◽  
Retinal Degeneration ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Photoreceptor Degeneration ◽  
Quantitative Metabolomics ◽  
Fatty Acid Amides ◽  
Age Related

Photoreceptor degeneration is characteristic of vision-threatening diseases including age-related macular degeneration. Photoreceptors are metabolically demanding cells in the retina, but specific details about their metabolic behaviours are unresolved. The quantitative metabolomics of retinal degeneration could provide valuable insights and inform future therapies. Here, we determined the metabolomic ‘fingerprint’ of healthy and dystrophic retinas in rat models using optimized metabolite extraction techniques. A number of classes of metabolites were consistently dysregulated during degeneration: vitamin A analogues, fatty acid amides, long-chain polyunsaturated fatty acids, acyl carnitines and several phospholipid species. For the first time, a distinct temporal trend of several important metabolites including DHA (4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoic acid), all- trans -retinal and its toxic end-product N -retinyl- N -retinylidene-ethanolamine were observed between healthy and dystrophic retinas. In this study, metabolomics was further used to determine the temporal effects of the therapeutic intervention of grafting stem cell-derived retinal pigment epithelium (RPE) in dystrophic retinas, which significantly prevented photoreceptor atrophy in our previous studies. The result revealed that lipid levels such as phosphatidylethanolamine in eyes were restored in those animals receiving the RPE grafts. In conclusion, this study provides insight into the metabolomics of retinal degeneration, and further understanding of the efficacy of RPE transplantation. This article is part of the themed issue ‘Quantitative mass spectrometry’.

scholarly journals Transcriptomic Profiling of Human Pluripotent Stem Cell-Derived Retinal Pigment Epithelium Over Time

2019 ◽  
Author(s):  
Grace E. Lidgerwood ◽  
Anne Senabouth ◽  
Casey J.A. Smith-Anttila ◽  
Vikkitharan Gnanasambandapillai ◽  
Dominik C. Kaczorowski ◽  
...  
Keyword(s):  
Stem Cell ◽  
Retinal Pigment Epithelium ◽  
Pluripotent Stem Cell ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Embryonic Stem Cell Line ◽  
Embryonic Stem ◽  
Human Pluripotent Stem Cell ◽  
Mesenchymal Transition ◽  
Rpe Cells

AbstractHuman pluripotent stem cell (hPSC)-derived progenies are immature versions of cells, presenting a potential limitation to the accurate modelling of disease associated with maturity or age. Hence, it is important to characterise how closely cells used in culture resemble their native counterparts. In order to select appropriate points in time for RPE cultures to reflect native counterparts, we characterised the transcriptomic profiles of hPSC-derived retinal pigment epithelium (RPE) cells from 1- and 12-month cultures. We differentiated the human embryonic stem cell line H9 into RPE cells, performed single cell RNA-sequencing of a total of 16,576 cells, and analysed the resulting data to assess the molecular changes of RPE cells across these two culture time points. Our results indicate the stability of the RPE transcriptomic signature, with no evidence of an epithelial – mesenchymal transition, and with maturing populations of RPE observed with time in culture. Assessment of gene ontology pathways revealed that as cultures age, RPE cells upregulate expression of genes involved in metal binding and antioxidant functions. This might reflect an increased ability to handle oxidative stress as cells mature. Comparison with native human RPE data confirmed a maturing transcriptional profile of RPE cells in culture. These results suggest that in vitro long-term culture of RPE cells allow the modelling of specific phenotypes observed in native mature tissue. Our work highlights the transcriptional landscape of hPSC-derived RPE as they age in culture, which provides a reference for native and patient-samples to be benchmarked against.

scholarly journals Loss of PGC-1α in RPE induces mesenchymal transition and promotes retinal degeneration

2019 ◽  
Vol 2 (3) ◽  
pp. e201800212 ◽  
Author(s):  
Mariana Aparecida Brunini Rosales ◽  
Daisy Y Shu ◽  
Jared Iacovelli ◽  
Magali Saint-Geniez
Keyword(s):  
Visual Processing ◽  
Epithelial To Mesenchymal Transition ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Conditional Knockout ◽  
Age Related Macular Degeneration ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Mesenchymal Transition ◽  
Age Related

The retinal pigment epithelium (RPE) supports visual processing and photoreceptor homeostasis via energetically demanding cellular functions. Here, we describe the consequences of repressing peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α), a master regulator of mitochondrial function and biogenesis, on RPE epithelial integrity. The sustained silencing of PGC-1α in differentiating human RPE cells affected mitochondria/autophagy function, redox state, and impaired energy sensor activity ultimately inducing epithelial to mesenchymal transition (EMT). Adult conditional knockout of PGC-1 coactivators in mice resulted in rapid RPE dysfunction and transdifferentiation associated with severe photoreceptor degeneration. RPE anomalies were characteristic of autophagic defect and mesenchymal transition comparable with the ones observed in age-related macular degeneration. These findings demonstrate that PGC-1α is required to maintain the functional and phenotypic status of RPE by supporting the cells’ oxidative metabolism and autophagy-mediated repression of EMT.

scholarly journals Clinical-grade stem cell–derived retinal pigment epithelium patch rescues retinal degeneration in rodents and pigs

2019 ◽  
Vol 11 (475) ◽  
pp. eaat5580 ◽  
Author(s):  
Ruchi Sharma ◽  
Vladimir Khristov ◽  
Aaron Rising ◽  
Balendu Shekhar Jha ◽  
Roba Dejene ◽  
...  
Keyword(s):  
Stem Cell ◽  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Clinical Grade ◽  
Functional Validation ◽  
Age Related

Considerable progress has been made in testing stem cell–derived retinal pigment epithelium (RPE) as a potential therapy for age-related macular degeneration (AMD). However, the recent reports of oncogenic mutations in induced pluripotent stem cells (iPSCs) underlie the need for robust manufacturing and functional validation of clinical-grade iPSC-derived RPE before transplantation. Here, we developed oncogenic mutation-free clinical-grade iPSCs from three AMD patients and differentiated them into clinical-grade iPSC-RPE patches on biodegradable scaffolds. Functional validation of clinical-grade iPSC-RPE patches revealed specific features that distinguished transplantable from nontransplantable patches. Compared to RPE cells in suspension, our biodegradable scaffold approach improved integration and functionality of RPE patches in rats and in a porcine laser-induced RPE injury model that mimics AMD-like eye conditions. Our results suggest that the in vitro and in vivo preclinical functional validation of iPSC-RPE patches developed here might ultimately be useful for evaluation and optimization of autologous iPSC-based therapies.

scholarly journals Phase 1 clinical study of an embryonic stem cell–derived retinal pigment epithelium patch in age-related macular degeneration

2018 ◽  
Vol 36 (4) ◽  
pp. 328-337 ◽  
Author(s):  
Lyndon da Cruz ◽  
Kate Fynes ◽  
Odysseas Georgiadis ◽  
Julie Kerby ◽  
Yvonne H Luo ◽  
...  
Keyword(s):  
Stem Cell ◽  
Clinical Study ◽  
Retinal Pigment Epithelium ◽  
Embryonic Stem Cell ◽  
Pigment Epithelium ◽  
Phase 1 ◽  
Retinal Pigment ◽  
Embryonic Stem ◽  
Age Related Macular Degeneration ◽  
Age Related

scholarly journals Heterochromatin protects retinal pigment epithelium cells from oxidative damage by silencing p53 target genes

2018 ◽  
Vol 115 (17) ◽  
pp. E3987-E3995 ◽  
Author(s):  
Lili Gong ◽  
Fangyuan Liu ◽  
Zhen Xiong ◽  
Ruili Qi ◽  
Zhongwen Luo ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Oxidative Damage ◽  
Target Genes ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Critical Role ◽  
Age Related Macular Degeneration ◽  
Protective Function ◽  
Heterochromatin Formation ◽  
Age Related

Oxidative stress (OS)-induced retinal pigment epithelium (RPE) cell apoptosis is critically implicated in the pathogenesis of age-related macular degeneration (AMD), a leading cause of blindness in the elderly. Heterochromatin, a compact and transcriptional inert chromatin structure, has been recently shown to be dynamically regulated in response to stress stimuli. The functional mechanism of heterochromatin on OS exposure is unclear, however. Here we show that OS increases heterochromatin formation both in vivo and in vitro, which is essential for protecting RPE cells from oxidative damage. Mechanistically, OS-induced heterochromatin selectively accumulates at p53-regulated proapoptotic target promoters and inhibits their transcription. Furthermore, OS-induced desumoylation of p53 promotes p53–heterochromatin interaction and regulates p53 promoter selection, resulting in the locus-specific recruitment of heterochromatin and transcription repression. Together, our findings demonstrate a protective function of OS-induced heterochromatin formation in which p53 desumoylation-guided promoter selection and subsequent heterochromatin recruitment play a critical role. We propose that targeting heterochromatin provides a plausible therapeutic strategy for the treatment of AMD.

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