Surgical Retinal Explants as a Source of Retinal Progenitor Cells

Too, Lay Khoon; Shen, Weiyong; Mammo, Zaid; Osaadon, Perach; Gillies, Mark C; Simunovic, Matthew P.

doi:10.1097/iae.0000000000003137

Cited by 4 publications

(9 citation statements)

References 27 publications

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“…The surgical or cadaveric retinal tissue was transferred immediately into a tissue culture insert containing 300 μL of pre-warmed neurobasal A media supplemented with 2% B27 supplement, 1% N2 supplement, 0.8 mM L-glutamine, 100 units/mL penicillin and 100 μg/mL streptomycin. The culture insert was subsequently placed within a well of a 24-well cell culture plate containing 400 μL of supplemented neurobasal A media 47 . The tissue was exposed or unexposed to the CamkIIα-bReachES-TS-eYFP treatment vector before www.nature.com/scientificreports/ incubation.…”

Section: Human Retinal Explantsmentioning

confidence: 99%

Optogenetic restoration of high sensitivity vision with bReaChES, a red-shifted channelrhodopsin

Too

Shen

Protti

et al. 2022

Sci Rep

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The common final pathway to blindness in many forms of retinal degeneration is the death of the light-sensitive primary retinal neurons. However, the normally light-insensitive second- and third-order neurons persist optogenetic gene therapy aims to restore sight by rendering such neurons light-sensitive. Here, we investigate whether bReaChES, a newly described high sensitivity Type I opsin with peak sensitivity to long-wavelength visible light, can restore vision in a murine model of severe early-onset retinal degeneration. Intravitreal injection of an adeno-associated viral vector carrying the sequence for bReaChES downstream of the calcium calmodulin kinase IIα promoter resulted in sustained retinal expression of bReaChES. Retinal ganglion cells (RGCs) expressing bReaChES generated action potentials at light levels consistent with bright indoor lighting (from 13.6 log photons cm−2 s−1). They could also detect flicker at up to 50 Hz, which approaches the upper temporal limit of human photopic vision. Topological response maps of bReaChES-expressing RGCs suggest that optogenetically activated RGCs may demonstrate similar topographical responses to RGCs stimulated by photoreceptor activation. Furthermore, treated dystrophic mice displayed restored cortical neuronal activity in response to light and rescued behavioral responses to a looming stimulus that simulated an aerial predator. Finally, human surgical retinal explants exposed to the bReaChES treatment vector demonstrated transduction. Together, these findings suggest that intravitreal gene therapy to deliver bReaChES to the retina may restore vision in human retinal degeneration in vivo at ecologically relevant light levels with spectral and temporal response characteristics approaching those of normal human photopic vision.

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Section: Human Retinal Explantsmentioning

confidence: 99%

Optogenetic restoration of high sensitivity vision with bReaChES, a red-shifted channelrhodopsin

Too

Shen

Protti

et al. 2022

Sci Rep

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“…These cells have been reported in the mature cadaveric human retina, where they were found predominantly in the retinal periphery ( Mayer et al, 2005 ; Bhatia et al, 2009 ; Too et al, 2017 ) and in the epiretinal membranes of patients with proliferative retinopathies ( Mayer et al, 2003 ; Johnsen et al, 2012 ). Recently, we identified retinal progenitor cells of MG lineage in surgical retinal explants excised from the mid-periphery of living donors undergoing rhegmatogenous retinal detachment repair ( Too et al, 2021 ). Together, these cells serve as a potentially important homologous – or autologous (if derived from living donors) – source of stem/progenitor cells that warrant further investigation of their potential in regenerative medicine.…”

Section: Functions Of Müller Glia In the Retinamentioning

confidence: 99%

“…Subsequent studies report that most, but not all, cadaveric or surgical retina could give rise to immortalized proliferation ( Lawrence et al, 2007 ; Giannelli et al, 2011 ), which is perhaps unsurprising given the diversity of genetic makeup and retinal microenvironment amongst human donors, as well as topographical variations in the retinal loci from which samples have been obtained. MG derived both from cadavers ( Lawrence et al, 2007 ) and living donors ( Giannelli et al, 2011 ; Too et al, 2021 ) have been shown to express stem/progenitor-cell protein markers, such as Sox2, Pax6, and Chx10. Furthermore, they can be induced by various cocktails of growth/differentiation factors for differentiation into post-mitotic retinal cells, such as rod- ( Giannelli et al, 2011 ; Jayaram et al, 2014 ) and RGC-precursors ( Singhal et al, 2012 ).…”

Section: Müller Glia For the Treatment Of Retinal Degenerationmentioning

confidence: 99%

“…The first challenge can be addressed via homologous transplantation or through genetic correction in patients with known genotypes, e.g., via CRISPR-Cas9 ( Burnight et al, 2017 ; Gallego et al, 2020 ). In the case of autologous/homologous hMG, these may be derived from surgical retinae ( Too et al, 2021 ) or harvested from retinal organoids derived from human iPSC or homologous ESC lines that comply with regulatory requirements for clinical development ( Nakano et al, 2012 ; Volkner et al, 2016 ; Eastlake et al, 2019 ). As with other stem cell derivatives, such as iPSC-derived photoreceptor precursors, the efficacy of host retinal integration of hMG for functional rescue, and the survival of these cells in the host retinal environment requires improvement.…”

Section: Müller Glia For the Treatment Of Retinal Degenerationmentioning

confidence: 99%

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Retinal Stem/Progenitor Cells Derived From Adult Müller Glia for the Treatment of Retinal Degeneration

Too

Simunovic

2021

Front. Cell Dev. Biol.

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Over the past two decades, progress in our understanding of glial function has been revolutionary. Within the retina, a subset of glial cells termed the “Müller glia (MG),” have been demonstrated to play key roles in retinal homeostasis, structure and metabolism. Additionally, MG have also been shown to possess the regenerative capacity that varies across species. In teleost fish, MG respond to injury by reprogramming into stem-like cells capable of regenerating lost tissue. The expression of stem/progenitor cell markers has been demonstrated broadly in mammalian MG, including human MG, but their in vivo regenerative capacity appears evolutionarily limited. Advances in stem cell therapy have progressively elucidated critical mechanisms underlying innate MG reprogramming in teleost fish, which have shown promising results when applied to rodents. Furthermore, when cultured ex vivo, MG from mammals can differentiate into several retina cell types. In this review, we will explore the reparative and regenerative potential of MG in cellular therapy approaches, and outline our current understanding of embryonic retinal development, the stem-cell potential of MG in adult vertebrate retina (including human), and microenvironmental cues that guide MG reprogramming.

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“…A recent work shows that culturing of human surgical retinal explants obtained from the equatorial retina reveals spontaneously migrating cells that express ESC markers, as Pax6 , Sox2, Nestin and also MGC markers, such as GFAP and glutamine synthetase. This implies that following injury, this area of the retina might provide a source of RPCs, since it generates cells that possess the potential for regeneration, with markers consistent with Müller cell lineage[ 225 ].…”

Section: Sc In Rd: Current Approachesmentioning

confidence: 99%

Retina stem cells, hopes and obstacles

German

Vallese-Maurizi

Soto

et al. 2021

WJSC

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Retinal degeneration is a major contributor to visual dysfunction worldwide. Although it comprises several eye diseases, loss of retinal pigment epithelial (RPE) and photoreceptor cells are the major contributors to their pathogenesis. Early therapies included diverse treatments, such as provision of anti-vascular endothelial growth factor and many survival and trophic factors that, in some cases, slow down the progression of the degeneration, but do not effectively prevent it. The finding of stem cells (SC) in the eye has led to the proposal of cell replacement strategies for retina degeneration. Therapies using different types of SC, such as retinal progenitor cells (RPCs), embryonic SC, pluripotent SCs (PSCs), induced PSCs (iPSCs), and mesenchymal stromal cells, capable of self-renewal and of differentiating into multiple cell types, have gained ample support. Numerous preclinical studies have assessed transplantation of SC in animal models, with encouraging results. The aim of this work is to revise the different preclinical and clinical approaches, analyzing the SC type used, their efficacy, safety, cell attachment and integration, absence of tumor formation and immunorejection, in order to establish which were the most relevant and successful. In addition, we examine the questions and concerns still open in the field. The data demonstrate the existence of two main approaches, aimed at replacing either RPE cells or photoreceptors. Emerging evidence suggests that RPCs and iPSC are the best candidates, presenting no ethical concerns and a low risk of immunorejection. Clinical trials have already supported the safety and efficacy of SC treatments. Serious concerns are pending, such as the risk of tumor formation, lack of attachment or integration of transplanted cells into host retinas, immunorejection, cell death, and also ethical. However, the amazing progress in the field in the last few years makes it possible to envisage safe and effective treatments to restore vision loss in a near future.

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Surgical Retinal Explants as a Source of Retinal Progenitor Cells

Cited by 4 publications

References 27 publications

Optogenetic restoration of high sensitivity vision with bReaChES, a red-shifted channelrhodopsin

Optogenetic restoration of high sensitivity vision with bReaChES, a red-shifted channelrhodopsin

Retinal Stem/Progenitor Cells Derived From Adult Müller Glia for the Treatment of Retinal Degeneration

Retina stem cells, hopes and obstacles

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