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Terheyden-Keighley D, Hühne M, Berger T, Hiller B, Martins S, Gamerschlag A, Sabour D, Meffert A, Kislat A, Slotta C, Hafezi F, Lichte J, Sudheer S, Tessmer K, Psathaki K, Ader M, Kogler G, Greber B. GMP-compliant iPS cell lines show widespread plasticity in a new set of differentiation workflows for cell replacement and cancer immunotherapy. Stem Cells Transl Med 2024:szae047. [PMID: 39042522 DOI: 10.1093/stcltm/szae047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 06/08/2024] [Indexed: 07/25/2024] Open
Abstract
Cell therapeutic applications based on induced pluripotent stem cells (iPSCs) appear highly promising and challenging at the same time. Good manufacturing practice (GMP) regulations impose necessary yet demanding requirements for quality and consistency when manufacturing iPSCs and their differentiated progeny. Given the scarcity of accessible GMP iPSC lines, we have established a corresponding production workflow to generate the first set of compliant cell banks. Hence, these lines met a comprehensive set of release specifications and, for instance, displayed a low overall mutation load reflecting their neonatal origin, cord blood. Based on these iPSC lines, we have furthermore developed a set of GMP-compatible workflows enabling improved gene targeting at strongly enhanced efficiencies and directed differentiation into critical cell types: A new protocol for the generation of retinal pigment epithelium (RPE) features a high degree of simplicity and efficiency. Mesenchymal stromal cells (MSCs) derived from iPSCs displayed outstanding expansion capacity. A fully optimized cardiomyocyte differentiation protocol was characterized by a particularly high batch-to-batch consistency at purities above 95%. Finally, we introduce a universal immune cell induction platform that converts iPSCs into multipotent precursor cells. These hematopoietic precursors could selectively be stimulated to become macrophages, T cells, or natural killer (NK) cells. A switch in culture conditions upon NK-cell differentiation induced a several thousand-fold expansion, which opens up perspectives for upscaling this key cell type in a feeder cell-independent approach. Taken together, these cell lines and improved manipulation platforms will have broad utility in cell therapy as well as in basic research.
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Affiliation(s)
| | | | | | - Björn Hiller
- Catalent Düsseldorf GmbH, 40764 Langenfeld, Germany
| | | | | | | | | | | | | | | | - Jens Lichte
- Catalent Düsseldorf GmbH, 40764 Langenfeld, Germany
| | | | - Karen Tessmer
- Center for Regenerative Therapies Dresden (CRTD) and Center for Molecular and Cellular Bioengineering, Dresden University of Technology, 01307 Dresden, Germany
| | - Katherina Psathaki
- Center for Cellular Nanoanalytics (CellNanOs), University of Osnabrück, 49076 Osnabrück, Germany
| | - Marius Ader
- Center for Regenerative Therapies Dresden (CRTD) and Center for Molecular and Cellular Bioengineering, Dresden University of Technology, 01307 Dresden, Germany
| | - Gesine Kogler
- Institute of Transplantation Diagnostics and Cell Therapeutics and Jose Carreras Stem Cell Bank, University Hospital of Düsseldorf, 40225 Düsseldorf, Germany
| | - Boris Greber
- Catalent Düsseldorf GmbH, 40764 Langenfeld, Germany
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2
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Wu S, Li F, Mo K, Huang H, Yu Y, Huang Y, Liu J, Li M, Tan J, Lin Z, Han Z, Wang L, Ouyang H. IGF2BP2 Maintains Retinal Pigment Epithelium Homeostasis by Stabilizing PAX6 and OTX2. Invest Ophthalmol Vis Sci 2024; 65:17. [PMID: 38861275 PMCID: PMC11174093 DOI: 10.1167/iovs.65.6.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 05/15/2024] [Indexed: 06/12/2024] Open
Abstract
Purpose N6-methyladenosine (m6A) methylation is a chemical modification that occurs on RNA molecules, where the hydrogen atom of adenine (A) nucleotides is replaced by a methyl group, forming N6-methyladenosine. This modification is a dynamic and reversible process that plays a crucial role in regulating various biological processes, including RNA stability, transport, translation, and degradation. Currently, there is a lack of research on the role of m6A modifications in maintaining the characteristics of RPE cells. m6A readers play a crucial role in executing the functions of m6A modifications, which prompted our investigation into their regulatory roles in the RPE. Methods Phagocytosis assays, immunofluorescence staining, flow cytometry experiments, β-galactosidase staining, and RNA sequencing (RNA-seq) were conducted to assess the functional and cellular characteristics changes in retinal pigment epithelium (RPE) cells following short-hairpin RNA-mediated knockdown of insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2). RNA-seq and ultraviolet crosslinking immunoprecipitation with high-throughput sequencing (HITS-CLIP) were employed to identify the target genes regulated by IGF2BP2. adeno-associated virus (AAV) subretinal injection was performed in 6- to 8-week-old C57 mice to reduce IGF2BP2 expression in the RPE, and the impact of IGF2BP2 knockdown on mouse visual function was assessed using immunofluorescence, quantitative real-time PCR, optical coherence tomography, and electroretinography. Results IGF2BP2 was found to have a pronounced effect on RPE phagocytosis. Subsequent in-depth exploration revealed that IGF2BP2 modulates the mRNA stability of PAX6 and OTX2, and the loss of IGF2BP2 induces inflammatory and aging phenotypes in RPE cells. IGF2BP2 knockdown impaired RPE function, leading to retinal dysfunction in vivo. Conclusions Our data suggest a crucial role of IGF2BP2 as an m6A reader in maintaining RPE homeostasis by regulating the stability of PAX6 and OTX2, making it a potential target for preventing the occurrence of retinal diseases related to RPE malfunction.
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Affiliation(s)
- Siqi Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
| | - Fuxi Li
- Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Kunlun Mo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
| | - Huaxing Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
| | - Yankun Yu
- Department of Pathology, The First Affiliated Hospital of Shihezi University, Shihezi, Xinjiang, China
| | - Ying Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
| | - Jiafeng Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
| | - Mingsen Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
| | - Jieying Tan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
| | - Zesong Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
| | - Zhuo Han
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
| | - Li Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
| | - Hong Ouyang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
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3
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Seidemann S, Salomon F, Hoffmann KB, Kurth T, Sbalzarini IF, Haase R, Ader M. Automated quantification of photoreceptor outer segments in developing and degenerating retinas on microscopy images across scales. Front Mol Neurosci 2024; 17:1398447. [PMID: 38854587 PMCID: PMC11157083 DOI: 10.3389/fnmol.2024.1398447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 04/17/2024] [Indexed: 06/11/2024] Open
Abstract
The functionality of photoreceptors, rods, and cones is highly dependent on their outer segments (POS), a cellular compartment containing highly organized membranous structures that generate biochemical signals from incident light. While POS formation and degeneration are qualitatively assessed on microscopy images, reliable methodology for quantitative analyses is still limited. Here, we developed methods to quantify POS (QuaPOS) maturation and quality on retinal sections using automated image analyses. POS formation was examined during the development and in adulthood of wild-type mice via light microscopy (LM) and transmission electron microscopy (TEM). To quantify the number, size, shape, and fluorescence intensity of POS, retinal cryosections were immunostained for the cone POS marker S-opsin. Fluorescence images were used to train the robust classifier QuaPOS-LM based on supervised machine learning for automated image segmentation. Characteristic features of segmentation results were extracted to quantify the maturation of cone POS. Subsequently, this quantification method was applied to characterize POS degeneration in "cone photoreceptor function loss 1" mice. TEM images were used to establish the ultrastructural quantification method QuaPOS-TEM for the alignment of POS membranes. Images were analyzed using a custom-written MATLAB code to extract the orientation of membranes from the image gradient and their alignment (coherency). This analysis was used to quantify the POS morphology of wild-type and two inherited retinal degeneration ("retinal degeneration 19" and "rhodopsin knock-out") mouse lines. Both automated analysis technologies provided robust characterization and quantification of POS based on LM or TEM images. Automated image segmentation by the classifier QuaPOS-LM and analysis of the orientation of membrane stacks by QuaPOS-TEM using fluorescent or TEM images allowed quantitative evaluation of POS formation and quality. The assessments showed an increase in POS number, volume, and membrane coherency during wild-type postnatal development, while a decrease in all three observables was detected in different retinal degeneration mouse models. All the code used for the presented analysis is open source, including example datasets to reproduce the findings. Hence, the QuaPOS quantification methods are useful for in-depth characterization of POS on retinal sections in developmental studies, for disease modeling, or after therapeutic interventions affecting photoreceptors.
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Affiliation(s)
- Suse Seidemann
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
- Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Dresden, Germany
| | - Florian Salomon
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
- Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Dresden, Germany
| | - Karl B. Hoffmann
- Faculty of Computer Science, Technische Universität Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
| | - Thomas Kurth
- Core Facility Electron Microscopy and Histology, Technology Platform, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Dresden, Germany
| | - Ivo F. Sbalzarini
- Faculty of Computer Science, Technische Universität Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
- DFG Cluster of Excellence “Physics of Life”, Technische Universität Dresden, Dresden, Germany
- Center for Scalable Data Analytics and Artificial Intelligence (ScaDS.AI), Leipzig University, Leipzig, Germany
| | - Robert Haase
- DFG Cluster of Excellence “Physics of Life”, Technische Universität Dresden, Dresden, Germany
- Center for Scalable Data Analytics and Artificial Intelligence (ScaDS.AI), Leipzig University, Leipzig, Germany
| | - Marius Ader
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
- Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Dresden, Germany
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Carido M, Völkner M, Steinheuer LM, Wagner F, Kurth T, Dumler N, Ulusoy S, Wieneke S, Norniella AV, Golfieri C, Khattak S, Schönfelder B, Scamozzi M, Zoschke K, Canzler S, Hackermüller J, Ader M, Karl MO. Reliability of human retina organoid generation from hiPSC-derived neuroepithelial cysts. Front Cell Neurosci 2023; 17:1166641. [PMID: 37868194 PMCID: PMC10587494 DOI: 10.3389/fncel.2023.1166641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 09/18/2023] [Indexed: 10/24/2023] Open
Abstract
The possible applications for human retinal organoids (HROs) derived from human induced pluripotent stem cells (hiPSC) rely on the robustness and transferability of the methodology for their generation. Standardized strategies and parameters to effectively assess, compare, and optimize organoid protocols are starting to be established, but are not yet complete. To advance this, we explored the efficiency and reliability of a differentiation method, called CYST protocol, that facilitates retina generation by forming neuroepithelial cysts from hiPSC clusters. Here, we tested seven different hiPSC lines which reproducibly generated HROs. Histological and ultrastructural analyses indicate that HRO differentiation and maturation are regulated. The different hiPSC lines appeared to be a larger source of variance than experimental rounds. Although previous reports have shown that HROs in several other protocols contain a rather low number of cones, HROs from the CYST protocol are consistently richer in cones and with a comparable ratio of cones, rods, and Müller glia. To provide further insight into HRO cell composition, we studied single cell RNA sequencing data and applied CaSTLe, a transfer learning approach. Additionally, we devised a potential strategy to systematically evaluate different organoid protocols side-by-side through parallel differentiation from the same hiPSC batches: In an explorative study, the CYST protocol was compared to a conceptually different protocol based on the formation of cell aggregates from single hiPSCs. Comparing four hiPSC lines showed that both protocols reproduced key characteristics of retinal epithelial structure and cell composition, but the CYST protocol provided a higher HRO yield. So far, our data suggest that CYST-derived HROs remained stable up to at least day 200, while single hiPSC-derived HROs showed spontaneous pathologic changes by day 200. Overall, our data provide insights into the efficiency, reproducibility, and stability of the CYST protocol for generating HROs, which will be useful for further optimizing organoid systems, as well as for basic and translational research applications.
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Affiliation(s)
- Madalena Carido
- Center for Regenerative Therapies Dresden (CRTD), TU Dresden, Dresden, Germany
| | - Manuela Völkner
- Center for Regenerative Therapies Dresden (CRTD), TU Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Lisa Maria Steinheuer
- Department Computational Biology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
- Department of Computer Science, Leipzig University, Leipzig, Germany
| | - Felix Wagner
- Center for Regenerative Therapies Dresden (CRTD), TU Dresden, Dresden, Germany
| | - Thomas Kurth
- Center for Molecular and Cellular Bioengineering (CMCB), Technology Platform, Core Facility Electron Microscopy and Histology, TU Dresden, Dresden, Germany
| | - Natalie Dumler
- Center for Regenerative Therapies Dresden (CRTD), TU Dresden, Dresden, Germany
| | - Selen Ulusoy
- Center for Regenerative Therapies Dresden (CRTD), TU Dresden, Dresden, Germany
| | - Stephanie Wieneke
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | | | - Cristina Golfieri
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Shahryar Khattak
- Center for Molecular and Cellular Bioengineering (CMCB), Stem Cell Engineering Facility, TU Dresden, Dresden, Germany
| | - Bruno Schönfelder
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Maria Scamozzi
- Center for Regenerative Therapies Dresden (CRTD), TU Dresden, Dresden, Germany
| | - Katja Zoschke
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Sebastian Canzler
- Department Computational Biology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Jörg Hackermüller
- Department Computational Biology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
- Department of Computer Science, Leipzig University, Leipzig, Germany
| | - Marius Ader
- Center for Regenerative Therapies Dresden (CRTD), TU Dresden, Dresden, Germany
| | - Mike O Karl
- Center for Regenerative Therapies Dresden (CRTD), TU Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
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5
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Lieffrig SA, Gyimesi G, Mao Y, Finnemann SC. Clearance phagocytosis by the retinal pigment epithelial during photoreceptor outer segment renewal: Molecular mechanisms and relation to retinal inflammation. Immunol Rev 2023; 319:81-99. [PMID: 37555340 PMCID: PMC10615845 DOI: 10.1111/imr.13264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 07/18/2023] [Indexed: 08/10/2023]
Abstract
Mammalian photoreceptor outer segment renewal is a highly coordinated process that hinges on timed cell signaling between photoreceptor neurons and the adjacent retinal pigment epithelial (RPE). It is a strictly rhythmic, synchronized process that underlies in part circadian regulation. We highlight findings from recently developed methods that quantify distinct phases of outer segment renewal in retinal tissue. At light onset, outer segments expose the conserved "eat-me" signal phosphatidylserine exclusively at their distal, most aged tip. A coordinated two-receptor efferocytosis process follows, in which ligands bridge outer segment phosphatidylserine with the RPE receptors αvβ5 integrin, inducing cytosolic signaling toward Rac1 and focal adhesion kinase/MERTK, and with MERTK directly, additionally inhibiting RhoA/ROCK and thus enabling F-actin dynamics favoring outer segment fragment engulfment. Photoreceptors and RPE persist for life with each RPE cell in the eye servicing dozens of overlying photoreceptors. Thus, RPE cells phagocytose more often and process more material than any other cell type. Mutant mice with impaired outer segment renewal largely retain functional photoreceptors and retinal integrity. However, when anti-inflammatory signaling in the RPE via MERTK or the related TYRO3 is lacking, catastrophic inflammation leads to immune cell infiltration that swiftly destroys the retina causing blindness.
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Affiliation(s)
- Stephanie A. Lieffrig
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY
| | - Gavin Gyimesi
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY
| | | | - Silvia C. Finnemann
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY
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6
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Si Z, Zheng Y, Zhao J. The Role of Retinal Pigment Epithelial Cells in Age-Related Macular Degeneration: Phagocytosis and Autophagy. Biomolecules 2023; 13:901. [PMID: 37371481 DOI: 10.3390/biom13060901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/11/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
Age-related macular degeneration (AMD) causes vision loss in the elderly population. Dry AMD leads to the formation of Drusen, while wet AMD is characterized by cell proliferation and choroidal angiogenesis. The retinal pigment epithelium (RPE) plays a key role in AMD pathogenesis. In particular, helioreceptor renewal depends on outer segment phagocytosis of RPE cells, while RPE autophagy can protect cells from oxidative stress damage. However, when the oxidative stress burden is too high and homeostasis is disturbed, the phagocytosis and autophagy functions of RPE become damaged, leading to AMD development and progression. Hence, characterizing the roles of RPE cell phagocytosis and autophagy in the pathogenesis of AMD can inform the development of potential therapeutic targets to prevent irreversible RPE and photoreceptor cell death, thus protecting against AMD.
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Affiliation(s)
- Zhibo Si
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
| | - Yajuan Zheng
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
| | - Jing Zhao
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
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7
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Umapathy A, Torten G, Paniagua AE, Chung J, Tomlinson M, Lim C, Williams DS. Spatiotemporal Live-Cell Analysis of Photoreceptor Outer Segment Membrane Ingestion by the Retinal Pigment Epithelium Reveals Actin-Regulated Scission. J Neurosci 2023; 43:2653-2664. [PMID: 36878726 PMCID: PMC10089248 DOI: 10.1523/jneurosci.1726-22.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 03/08/2023] Open
Abstract
The photoreceptor outer segment (OS) is the phototransductive organelle in the vertebrate retina. OS tips are regularly ingested and degraded by the adjacent retinal pigment epithelium (RPE), offsetting the addition of new disk membrane at the base of the OS. This catabolic role of the RPE is essential for photoreceptor health, with defects in ingestion or degradation underlying different forms of retinal degeneration and blindness. Although proteins required for OS tip ingestion have been identified, spatiotemporal analysis of the ingestion process in live RPE cells is lacking; hence, the literature reflects no common understanding of the cellular mechanisms that affect ingestion. We imaged live RPE cells from mice (both sexes) to elucidate the ingestion events in real time. Our imaging revealed roles for f-actin dynamics and specific dynamic localizations of two BAR (Bin-Amphiphysin-Rvs) proteins, FBP17 and AMPH1-BAR, in shaping the RPE apical membrane as it surrounds the OS tip. Completion of ingestion was observed to occur by scission of the OS tip from the remainder of the OS, with a transient concentration of f-actin forming around the site of imminent scission. Actin dynamics were also required for regulating the size of the ingested OS tip, and the time course of the overall ingestion process. The size of the ingested tip is consistent with the term "phagocytosis." However, phagocytosis usually refers to engulfment of an entire particle or cell, whereas our observations of OS tip scission indicate a process that is more specifically described as "trogocytosis," in which one cell "nibbles" another cell.SIGNIFICANCE STATEMENT The ingestion of the photoreceptor outer segment (OS) tips by the retinal pigment epithelium (RPE) is a dynamic cellular process that has fascinated scientists for 60 years. Yet its molecular mechanisms had not been addressed in living cells. We developed a live-cell imaging approach to investigate OS tip ingestion, and focused on the dynamic participation of actin filaments and membrane-shaping BAR proteins. We observed scission of OS tips for the first time, and were able to monitor local changes in protein concentration preceding, during, and following scission. Our approach revealed that actin filaments were concentrated at the site of OS scission and were required for regulating the size of the ingested OS tip and the time course of the ingestion process.
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Affiliation(s)
- Ankita Umapathy
- Department of Ophthalmology and Stein Eye Institute, and Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Gil Torten
- Department of Ophthalmology and Stein Eye Institute, and Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Antonio E Paniagua
- Department of Ophthalmology and Stein Eye Institute, and Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Julie Chung
- Department of Ophthalmology and Stein Eye Institute, and Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Madeline Tomlinson
- Department of Ophthalmology and Stein Eye Institute, and Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Caleb Lim
- Department of Ophthalmology and Stein Eye Institute, and Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - David S Williams
- Department of Ophthalmology and Stein Eye Institute, and Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
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Piskova T, Kozyrina AN, Di Russo J. Mechanobiological implications of age-related remodelling in the outer retina. BIOMATERIALS ADVANCES 2023; 147:213343. [PMID: 36801797 DOI: 10.1016/j.bioadv.2023.213343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/01/2023] [Accepted: 02/10/2023] [Indexed: 02/17/2023]
Abstract
The outer retina consists of the light-sensitive photoreceptors, the pigmented epithelium, and the choroid, which interact in a complex manner to sustain homeostasis. The organisation and function of these cellular layers are mediated by the extracellular matrix compartment named Bruch's membrane, situated between the retinal epithelium and the choroid. Like many tissues, the retina experiences age-related structural and metabolic changes, which are relevant for understanding major blinding diseases of the elderly, such as age-related macular degeneration. Compared with other tissues, the retina mainly comprises postmitotic cells, making it less able to maintain its mechanical homeostasis over the years functionally. Aspects of retinal ageing, like the structural and morphometric changes of the pigment epithelium and the heterogenous remodelling of the Bruch's membrane, imply changes in tissue mechanics and may affect functional integrity. In recent years, findings in the field of mechanobiology and bioengineering highlighted the importance of mechanical changes in tissues for understanding physiological and pathological processes. Here, we review the current knowledge of age-related changes in the outer retina from a mechanobiological perspective, aiming to generate food for thought for future mechanobiology studies in the outer retina.
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Affiliation(s)
- Teodora Piskova
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University, Pauwelstrasse 30, 52074 Aachen, Germany; Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
| | - Aleksandra N Kozyrina
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University, Pauwelstrasse 30, 52074 Aachen, Germany; Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
| | - Jacopo Di Russo
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University, Pauwelstrasse 30, 52074 Aachen, Germany; Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany; DWI - Leibniz-Institute for Interactive Materials, Forckenbeckstrasse 50, 52074 Aachen, Germany.
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9
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Cellular and Molecular Mechanisms of Pathogenesis Underlying Inherited Retinal Dystrophies. Biomolecules 2023; 13:biom13020271. [PMID: 36830640 PMCID: PMC9953031 DOI: 10.3390/biom13020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/23/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Inherited retinal dystrophies (IRDs) are congenital retinal degenerative diseases that have various inheritance patterns, including dominant, recessive, X-linked, and mitochondrial. These diseases are most often the result of defects in rod and/or cone photoreceptor and retinal pigment epithelium function, development, or both. The genes associated with these diseases, when mutated, produce altered protein products that have downstream effects in pathways critical to vision, including phototransduction, the visual cycle, photoreceptor development, cellular respiration, and retinal homeostasis. The aim of this manuscript is to provide a comprehensive review of the underlying molecular mechanisms of pathogenesis of IRDs by delving into many of the genes associated with IRD development, their protein products, and the pathways interrupted by genetic mutation.
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Iwagawa T, Masumoto H, Tabuchi H, Tani K, Conklin BR, Watanabe S. Evaluation of CRISPR/Cas9 exon-skipping vector for choroideremia using human induced pluripotent stem cell-derived RPE. J Gene Med 2023; 25:e3464. [PMID: 36413603 PMCID: PMC9898118 DOI: 10.1002/jgm.3464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 10/21/2022] [Accepted: 11/13/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Exon-skipping is a powerful genetic tool, especially when delivering genes using an AAV-mediated full-length gene supplementation strategy is difficult owing to large length of genes. Here, we used engineered human induced pluripotent stem cells and artificial intelligence to evaluate clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9-based exon-skipping vectors targeting genes of the retinal pigment epithelium (RPE). The model system was choroideremia; this is an X-linked inherited retinal disease caused by mutation of the CHM gene. METHODS We explored whether artificial intelligence detected differentiation of human OTX2, PAX6 and MITF (hOPM) cells, in which OTX2, PAX6 and MITF expression was induced by doxycycline treatment, into RPE. Plasmid encoding CHM exon-skipping modules targeting the splice donor sites of exons 6 were constructed. A clonal hOPM cell line with a frameshift mutation in exon 6 was generated and differentiated into RPE. CHM exon 6-skipping was induced, and the effects of skipping on phagocytic activity, cell death and prenylation of Rab small GTPase (RAB) were evaluated using flow cytometry, an in vitro prenylation assay and western blotting. RESULTS Artificial intelligence-based evaluation of RPE differentiation was successful. Retinal pigment epithelium cells with a frameshift mutation in exon 6 showed increased cell death, reduced phagocytic activity and increased cytosolic unprenylated RABs only when oxidative stress was in play. The latter two phenotypes were partially rescued by exon 6-skipping of CHM. CONCLUSIONS CHM exon 6-skipping contributed to RPE phagocytosis probably by increasing RAB38 prenylation under oxidative stress.
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Affiliation(s)
- Toshiro Iwagawa
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
- Department of Retinal Biology and Pathology, University of Tokyo Hospital, University of Tokyo, Tokyo, Japan
| | - Hiroki Masumoto
- Xeno Hoc, inc
- Department of Ophthalmology, Tsukazaki Hospital, Hyogo, Japan
| | - Hitoshi Tabuchi
- Department of Ophthalmology, Tsukazaki Hospital, Hyogo, Japan
- Department of Technology and Design Thinking for Medicine, Hiroshima University, Hiroshima, Japan
| | - Kenzaburo Tani
- Laboratory of ALA Advanced Medical Research, Institute for quantitative Biosciences, University of Tokyo, Tokyo, Japan
| | - Bruce R. Conklin
- Gladstone Institutes, San Francisco, CA, USA
- Departments of Medicine, Ophthalmology & Cellular and Molecular Pharmacology University of California, San Francisco, CA, United States, USA
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
- Department of Retinal Biology and Pathology, University of Tokyo Hospital, University of Tokyo, Tokyo, Japan
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11
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Li W, Tan J, He S, Yue Y, Liu H, Li R, Wang X, Wang G, Fan W, Zhao C, Zhou Q, Yang P, Hou S. iPSC-based model of Vogt-Koyanagi-Harada disease for phenotype recapitulation and drug screening. Clin Immunol 2023; 246:109205. [PMID: 36509389 DOI: 10.1016/j.clim.2022.109205] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 11/10/2022] [Accepted: 11/23/2022] [Indexed: 12/14/2022]
Abstract
Vogt-Koyanagi-Harada (VKH) disease, a major blinding eye disease, is characterized by an autoimmune response against melanocytes in multiple organs throughout the body. Currently, the aetiology and pathogenesis of VKH disease are unclear, and the treatment strategy needs to be further optimized. The retinal pigment epithelium (RPE), a monolayer of pigmented cells of the fundus, is essential for maintaining normal visual function and is involved in both the acute and chronic stages of VKH disease. Therefore, the functions of the RPE may play a critical role in the aetiology and treatment of VKH disease. Herein, we established a human induced pluripotent stem cell (hiPSC) RPE model of VKH disease by reprogramming peripheral blood mononuclear cells (PBMCs) into iPSCs and then differentiating them into RPE cells. Patient-derived RPE cells exhibited barrier disruption, impaired phagocytosis, and depigmentation compared with those from normal controls, which was consistent with the features of VKH disease. Furthermore, a small molecular compound targeting EGR2 was found to rescue the barrier and phagocytic functions of the hiPSC-RPE cells through high-throughput virtual screening and functional studies, suggesting a promising strategy for the treatment of VKH disease.
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Affiliation(s)
- Wanqian Li
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Jun Tan
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Siyuan He
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Yingying Yue
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Huan Liu
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Ruonan Li
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Xiaotang Wang
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Guoqing Wang
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Wei Fan
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Chenyang Zhao
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Qian Zhou
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Peizeng Yang
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China..
| | - Shengping Hou
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Ophthalmology, Chongqing, China; Chongqing Eye Institute, Chongqing, China; Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing, China..
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12
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Yefimova MG. Myelinosome organelles in pathological retinas: ubiquitous presence and dual role in ocular proteostasis maintenance. Neural Regen Res 2022; 18:1009-1016. [PMID: 36254982 PMCID: PMC9827766 DOI: 10.4103/1673-5374.355753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The timely and efficient elimination of aberrant proteins and damaged organelles, formed in response to various genetic and environmental stressors, is a vital need for all cells of the body. Recent lines of evidence point out several non-classical strategies employed by ocular tissues to cope with aberrant constituents generated in the retina and in the retinal pigmented epithelium cells exposed to various stressors. Along with conventional strategies relying upon the intracellular degradation of aberrant constituents through ubiquitin-proteasome and/or lysosome-dependent autophagy proteolysis, two non-conventional mechanisms also contribute to proteostasis maintenance in ocular tissues. An exosome-mediated clearing and a myelinosome-driven secretion mechanism do not require intracellular degradation but provide the export of aberrant constituents and "waste proteins" outside of the cells. The current review is centered on the non-degradative myelinosome-driven secretion mechanism, which operates in the retina of transgenic Huntington's disease R6/1 model mice. Myelinosome-driven secretion is supported by rare organelles myelinosomes that are detected not only in degenerative Huntington's disease R6/1 retina but also in various pathological states of the retina and of the retinal pigmented epithelium. The intra-retinal traffic and inter-cellular exchange of myelinosomes was discussed in the context of a dual role of the myelinosome-driven secretion mechanism for proteostasis maintenance in different ocular compartments. Special focus was made on the interplay between degradative and non-degradative strategies in ocular pathophysiology, to delineate potential therapeutic approaches to counteract several vision diseases.
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Affiliation(s)
- Marina G. Yefimova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St-Petersburg, Russia,Laboratoire STIM CNRS ERL 7003, Université de Poitiers, Poitiers, France,Correspondence to: Marina G. Yefimova, .
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13
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Feng L, Li H, Du Y, Zhang T, Zhu Y, Li Z, Zhao L, Wang X, Wang G, Zhou L, Jiang Z, Liu Z, Ou Z, Wen Y, Zhuo Y. Chaperonin-Containing TCP1 Subunit 5 Protects Against the Effect of Mer Receptor Tyrosine Kinase Knockdown in Retinal Pigment Epithelial Cells by Interacting With Filamentous Actin and Activating the LIM-Kinase 1/Cofilin Pathway. Front Med (Lausanne) 2022; 9:861371. [PMID: 35492354 PMCID: PMC9043132 DOI: 10.3389/fmed.2022.861371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/09/2022] [Indexed: 11/16/2022] Open
Abstract
Retinitis pigmentosa (RP), characterized by the gradual loss of rod and cone photoreceptors that eventually leads to blindness, is the most common inherited retinal disorder, affecting more than 2.5 million people worldwide. However, the underlying pathogenesis of RP remains unclear and there is no effective cure for RP. Mutations in the Mer receptor tyrosine kinase (MERTK) gene induce the phagocytic dysfunction of retinal pigment epithelium (RPE) cells, leading to RP. Studies have indicated that filamentous actin (F-actin)—which is regulated by chaperonin-containing TCP1 subunit 5 (CCT5)—plays a vital role in phagocytosis in RPE cells. However, whether CCT5/F-actin signaling is involved in MERTK-associated RP remains largely unknown. In the present study, we specifically knocked down MERTK and CCT5 through siRNA transfection and examined the expression of CCT5 and F-actin in human primary RPE (HsRPE) cells. We found that MERTK downregulation inhibited cell proliferation, migration, and phagocytic function; significantly decreased the expression of F-actin; and disrupted the regular arrangement of F-actin. Importantly, our findings firstly indicate that CCT5 interacts with F-actin and is inhibited by MERTK siRNA in HsRPE cells. Upregulating CCT5 using CCT5-specific lentiviral vectors (CCT5-Le) rescued the cell proliferation, migration, and phagocytic function of HsRPE cells under the MERTK knockdown condition by increasing the expression of F-actin and restoring its regular arrangement via the LIMK1/cofilin, but not the SSH1/cofilin, pathway. In conclusion, CCT5 protects against the effect of MERTK knockdown in HsRPE cells and demonstrates the potential for effective treatment of MERTK-associated RP.
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Affiliation(s)
- Lujia Feng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Haichun Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Yong Du
- Guizhou Provincial People's Hospital, Guizhou University, Guiyang, China
| | - Ting Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Yingting Zhu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Zhidong Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Ling Zhao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Xing Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Gongpei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Linbin Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Zhaorong Jiang
- Ophthalmology Department of Zhuhai Integrated Traditional Chinese and Western Medicine Hospital, Zhuhai, China
| | - Zheng Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Zhancong Ou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Yuwen Wen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
| | - Yehong Zhuo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China
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14
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Stem cell transplantation as a progressing treatment for retinitis pigmentosa. Cell Tissue Res 2022; 387:177-205. [PMID: 35001210 DOI: 10.1007/s00441-021-03551-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 10/27/2021] [Indexed: 11/02/2022]
Abstract
Retinal degenerative diseases such as retinitis pigmentosa (RP) are of the major causes of vision loss in developed countries. Despite the unclear pathophysiology, treatment methods have been investigated vastly in the past decades. This review article mainly discusses the advances in application of stem cell and progenitor transplantation for retinitis pigmentosa. Stem cell sources such as mesenchymal stem cells, embryonic stem cells, induced pluripotent stem cells, neural stem cells, retinal progenitor cells, and olfactory ensheathing cells are discussed separately in addition to a brief description of two approaches for treatment of early-stage RP, including gene therapy and nutritional therapy.
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15
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Korkka I, Skottman H, Nymark S. OUP accepted manuscript. Stem Cells Transl Med 2022; 11:753-766. [PMID: 35639962 PMCID: PMC9299513 DOI: 10.1093/stcltm/szac029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 04/09/2022] [Indexed: 11/15/2022] Open
Abstract
Human pluripotent stem cell (hPSC)-derived retinal pigment epithelium (RPE) is extensively used in RPE research, disease modeling, and transplantation therapies. For successful outcomes, a thorough evaluation of their physiological authenticity is a necessity. Essential determinants of this are the different ion channels of the RPE, yet studies evaluating this machinery in hPSC-RPE are scarce. We examined the functionality and localization of potassium (K+) channels in the human embryonic stem cell (hESC)-derived RPE. We observed a heterogeneous pattern of voltage-gated K+ (KV) and inwardly rectifying K+ (Kir) channels. Delayed rectifier currents were recorded from most of the cells, and immunostainings showed the presence of KV1.3 channel. Sustained M-currents were also present in the hESC-RPE, and based on immunostaining, these currents were carried by KCNQ1-KCNQ5 channel types. Some cells expressed transient A-type currents characteristic of native human fetal RPE (hfRPE) and cultured primary RPE and carried by KV1.4 and KV4.2 channels. Of the highly important Kir channels, we found that Kir7.1 is present both at the apical and basolateral membranes of the hESC- and fresh native mouse RPE. Kir currents, however, were recorded only from 14% of the hESC-RPE cells with relatively low amplitudes. Compared to previous studies, our data suggest that in the hESC-RPE, the characteristics of the delayed rectifier and M-currents resemble native adult RPE, while A-type and Kir currents resemble native hfRPE or cultured primary RPE. Overall, the channelome of the RPE is a sensitive indicator of maturity and functionality affecting its therapeutic utility.
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Affiliation(s)
- Iina Korkka
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Heli Skottman
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Soile Nymark
- Corresponding author: Soile Nymark, PhD, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520 Tampere, Finland. Tel: +358 40 849 0009; E-mail:
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MERTK-Mediated LC3-Associated Phagocytosis (LAP) of Apoptotic Substrates in Blood-Separated Tissues: Retina, Testis, Ovarian Follicles. Cells 2021; 10:cells10061443. [PMID: 34207717 PMCID: PMC8229618 DOI: 10.3390/cells10061443] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/05/2021] [Accepted: 06/07/2021] [Indexed: 01/22/2023] Open
Abstract
Timely and efficient elimination of apoptotic substrates, continuously produced during one’s lifespan, is a vital need for all tissues of the body. This task is achieved by cells endowed with phagocytic activity. In blood-separated tissues such as the retina, the testis and the ovaries, the resident cells of epithelial origin as retinal pigmented epithelial cells (RPE), testis Sertoli cells and ovarian granulosa cells (GC) provide phagocytic cleaning of apoptotic cells and cell membranes. Disruption of this process leads to functional ablation as blindness in the retina and compromised fertility in males and females. To ensure the efficient elimination of apoptotic substrates, RPE, Sertoli cells and GC combine various mechanisms allowing maintenance of tissue homeostasis and avoiding acute inflammation, tissue disorganization and functional ablation. In tight cooperation with other phagocytosis receptors, MERTK—a member of the TAM family of receptor tyrosine kinases (RTK)—plays a pivotal role in apoptotic substrate cleaning from the retina, the testis and the ovaries through unconventional autophagy-assisted phagocytosis process LAP (LC3-associated phagocytosis). In this review, we focus on the interplay between TAM RTKs, autophagy-related proteins, LAP, and Toll-like receptors (TLR), as well as the regulatory mechanisms allowing these components to sustain tissue homeostasis and prevent functional ablation of the retina, the testis and the ovaries.
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A Human Retinal Pigment Epithelium-Based Screening Platform Reveals Inducers of Photoreceptor Outer Segments Phagocytosis. Stem Cell Reports 2020; 15:1347-1361. [PMID: 33242397 PMCID: PMC7724476 DOI: 10.1016/j.stemcr.2020.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 11/20/2022] Open
Abstract
Phagocytosis is a key function in various cells throughout the body. A deficiency in photoreceptor outer segment (POS) phagocytosis by the retinal pigment epithelium (RPE) causes vision loss in inherited retinal diseases and possibly age-related macular degeneration. To date, there are no effective therapies available aiming at recovering the lost phagocytosis function. Here, we developed a high-throughput screening assay based on RPE derived from human embryonic stem cells (hRPE) to reveal enhancers of POS phagocytosis. One of the hits, ramoplanin (RM), reproducibly enhanced POS phagocytosis and ensheathment in hRPE, and enhanced the expression of proteins known to regulate membrane dynamics and ensheathment in other cell systems. Additionally, RM rescued POS internalization defect in Mer receptor tyrosine kinase (MERTK) mutant hRPE, derived from retinitis pigmentosa patient induced pluripotent stem cells. Our platform, including a primary phenotypic screening phagocytosis assay together with orthogonal assays, establishes a basis for RPE-based therapy discovery aiming at a broad patient spectrum.
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18
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Kwon W, Freeman SA. Phagocytosis by the Retinal Pigment Epithelium: Recognition, Resolution, Recycling. Front Immunol 2020; 11:604205. [PMID: 33281830 PMCID: PMC7691529 DOI: 10.3389/fimmu.2020.604205] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022] Open
Abstract
Tissue-resident phagocytes are responsible for the routine binding, engulfment, and resolution of their meals. Such populations of cells express appropriate surface receptors that are tailored to recognize the phagocytic targets of their niche and initiate the actin polymerization that drives internalization. Tissue-resident phagocytes also harbor enzymes and transporters along the endocytic pathway that orchestrate the resolution of ingested macromolecules from the phagolysosome. Solutes fluxed from the endocytic pathway and into the cytosol can then be reutilized by the phagocyte or exported for their use by neighboring cells. Such a fundamental metabolic coupling between resident phagocytes and the tissue in which they reside is well-emphasized in the case of retinal pigment epithelial (RPE) cells; specialized phagocytes that are responsible for the turnover of photoreceptor outer segments (POS). Photoreceptors are prone to photo-oxidative damage and their long-term health depends enormously on the disposal of aged portions of the outer segment. The phagocytosis of the POS by the RPE is the sole means of this turnover and clearance. RPE are themselves mitotically quiescent and therefore must resolve the ingested material to prevent their toxic accumulation in the lysosome that otherwise leads to retinal disorders. Here we describe the sequence of events underlying the healthy turnover of photoreceptors by the RPE with an emphasis on the signaling that ensures the phagocytosis of the distal POS and on the transport of solutes from the phagosome that supersedes its resolution. While other systems may utilize different receptors and transporters, the biophysical and metabolic manifestations of such events are expected to apply to all tissue-resident phagocytes that perform regular phagocytic programs.
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Affiliation(s)
- Whijin Kwon
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada
| | - Spencer A Freeman
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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