scholarly journals Retinal organoids: a window into human retinal development

Development ◽  
2020 ◽  
Vol 147 (24) ◽  
pp. dev189746
Author(s):  
Michelle O'Hara-Wright ◽  
Anai Gonzalez-Cordero
Keyword(s):  
Cell Fate ◽  
Developmental Trajectories ◽  
Retinal Development ◽  
Retinal Disease ◽  
Cell Types ◽  
Model Organisms ◽  
Retinal Cell ◽  
Human Retina ◽  
Cell Fate Decisions

ABSTRACTRetinal development and maturation are orchestrated by a series of interacting signalling networks that drive the morphogenetic transformation of the anterior developing brain. Studies in model organisms continue to elucidate these complex series of events. However, the human retina shows many differences from that of other organisms and the investigation of human eye development now benefits from stem cell-derived organoids. Retinal differentiation methods have progressed from simple 2D adherent cultures to self-organising micro-physiological systems. As models of development, these have collectively offered new insights into the previously unexplored early development of the human retina and informed our knowledge of the key cell fate decisions that govern the specification of light-sensitive photoreceptors. Although the developmental trajectories of other retinal cell types remain more elusive, the collation of omics datasets, combined with advanced culture methodology, will enable modelling of the intricate process of human retinogenesis and retinal disease in vitro.

scholarly journals Glucocorticoid agonists enhance retinal stem cell self-renewal and proliferation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kenneth N. Grisé ◽  
Nelson X. Bautista ◽  
Krystal Jacques ◽  
Brenda L. K. Coles ◽  
Derek van der Kooy
Keyword(s):  
Cell Fate ◽  
Progenitor Cell ◽  
Cell Types ◽  
Retinal Cell ◽  
Ciliary Epithelium ◽  
Cell Transplant ◽  
Self Renewal ◽  
Synthetic Glucocorticoid

Abstract Background Adult mammalian retinal stem cells (RSCs) readily proliferate, self-renew, and generate progeny that differentiate into all retinal cell types in vitro. RSC-derived progeny can be induced to differentiate into photoreceptors, making them a potential source for retinal cell transplant therapies. Despite their proliferative propensity in vitro, RSCs in the adult mammalian eye do not proliferate and do not have a regenerative response to injury. Thus, identifying and modulating the mechanisms that regulate RSC proliferation may enhance the capacity to produce RSC-derived progeny in vitro and enable RSC activation in vivo. Methods Here, we used medium-throughput screening to identify small molecules that can expand the number of RSCs and their progeny in culture. In vitro differentiation assays were used to assess the effects of synthetic glucocorticoid agonist dexamethasone on RSC-derived progenitor cell fate. Intravitreal injections of dexamethasone into adult mouse eyes were used to investigate the effects on endogenous RSCs. Results We discovered that high-affinity synthetic glucocorticoid agonists increase RSC self-renewal and increase retinal progenitor proliferation up to 6-fold without influencing their differentiation in vitro. Intravitreal injection of synthetic glucocorticoid agonist dexamethasone induced in vivo proliferation in the ciliary epithelium—the niche in which adult RSCs reside. Conclusions Together, our results identify glucocorticoids as novel regulators of retinal stem and progenitor cell proliferation in culture and provide evidence that GCs may activate endogenous RSCs.

scholarly journals Generation of a Retina Reporter hiPSC Line to Label Progenitor, Ganglion, and Photoreceptor Cell Types

2019 ◽  
Author(s):  
Phuong T. Lam ◽  
Christian Gutierrez ◽  
Katia Del Rio-Tsonis ◽  
Michael L. Robinson
Keyword(s):  
Fluorescent Protein ◽  
Ganglion Cells ◽  
Fluorescent Proteins ◽  
Retinal Development ◽  
Retinal Disease ◽  
Cell Types ◽  
Retinal Cell ◽  
Therapeutic Drug ◽  
Retina Development ◽  
Induced Pluripotent

ABSTRACTEarly in mammalian eye development, VSX2, BRN3b, and RCVRN expression marks neural retina progenitors (NRPs), retinal ganglion cells (RGCs), and photoreceptors (PRs), respectively. The ability to create retinal organoids from human induced pluripotent stem cells (hiPSC) holds great potential for modeling both human retinal development and retinal disease. However, no methods allowing the simultaneous, real-time monitoring of multiple specific retinal cell types during development currently exist. Here, we describe a CRISPR/Cas9 gene editing strategy to generate a triple transgenic reporter hiPSC line (PGP1) that utilizes the endogenous VSX2, BRN3b, and RCVRN promoters to specifically express fluorescent proteins (Cerulean in NRPs, eGFP in RGCs and mCherry in PRs) without disrupting the function of the endogenous alleles. Retinal organoid formation from the PGP1 line demonstrated the ability of the edited cells to undergo normal retina development while exhibiting appropriate fluorescent protein expression consistent with the onset of NRPs, RGCs, and PRs. Organoids produced from the PGP1 line expressed transcripts consistent with the development of all major retinal cell types. The PGP1 line offers a powerful new tool to study retinal development, retinal reprogramming, and therapeutic drug screening.

scholarly journals Niche mediated integrin signaling supports steady state hematopoiesis in spleen

2020 ◽  
Author(s):  
Shubham Haribhau Mehatre ◽  
Irene Mariam Roy ◽  
Atreyi Biswas ◽  
Devila Prit ◽  
Sarah Schouteden ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Types ◽  
Integrin Signaling ◽  
White Pulp ◽  
Differentiation Potential ◽  
Hematopoietic Stem ◽  
Cell Fate Decisions ◽  
Functional Regulation

AbstractOutside-in integrin signaling regulates cell fate decisions in a variety of cell types, including hematopoietic stem cells (HSCs). Our earlier published studies showed that interruption of Periostin (POSTN) and Integrin-αv (ITGAV) interaction induces faster proliferation in HSCs with developmental stage dependent functional effects. Here, we examined the role of POSTN-ITGAV axis in lympho-hematopoietic activity in spleen that hosts rare population of HSCs, the functional regulation of which is not clearly known. Vav-iCre mediated deletion of Itgav in hematopoietic system led to higher proliferation rates, resulting in increased frequency of primitive HSCs in adult spleen. However, in vitro CFU-C assays demonstrated a poorer differentiation potential following Itgav deletion. This also led to a decrease in the white pulp area with a significant decline in the B-cell numbers. Systemic deletion of its ligand, POSTN, phenocopied the effects noted in Vav-Itgav−/− mice. Histological examination of Postn deficient spleen also showed increase in the spleen trabecular areas. Surprisingly, these were the myofibroblasts of the trabecular and capsular areas that expressed high levels of POSTN within the spleen tissue. In addition, vascular smooth muscle cells also expressed POSTN. Through CFU-S12 assays, we showed that hematopoietic support potential of stroma in Postn deficient splenic hematopoietic niche was defective. Overall, we demonstrate that POSTN-ITGAV interaction plays important role in spleen lympho-hematopoiesis.

scholarly journals The vitamin D receptor in cancer

2008 ◽  
Vol 67 (2) ◽  
pp. 115-127 ◽  
Author(s):  
James Thorne ◽  
Moray J. Campbell
Keyword(s):  
Vitamin D ◽  
Cell Fate ◽  
Vitamin D Receptor ◽  
De Novo ◽  
Lithocholic Acid ◽  
Cell Types ◽  
Cell Fate Decisions ◽  
Wide Range

Over the last 25 years roles have been established for vitamin D receptor (VDR) in influencing cell proliferation and differentiation. For example, murine knock-out approaches have revealed a role for the VDR in controlling mammary gland growth and function. These actions appear widespread, as the enzymes responsible for 1α,25-dihydroxycholecalciferol generation and degradation, and the VDR itself, are all functionally present in a wide range of epithelial and haematopoietic cell types. These findings, combined with epidemiological and functional data, support the concept that local, autocrine and paracrine VDR signalling exerts control over cell-fate decisions in multiple cell types. Furthermore, the recent identification of bile acid lithocholic acid as a VDR ligand underscores the environmental sensing role for the VDR.In vitroandin vivodissection of VDR signalling in cancers (e.g. breast, prostate and colon) supports a role for targeting the VDR in either chemoprevention or chemotherapy settings. As with other potential therapeutics, it has become clear that cancer cells displayde novoand acquired genetic and epigenetic mechanisms of resistance to these actions. Consequently, a range of experimental and clinical options are being developed to bring about more targeted actions, overcome resistance and enhance the efficacy of VDR-centred therapeutics.

scholarly journals Cell types of the human retina and its organoids at single-cell resolution: developmental convergence, transcriptomic identity, and disease map

2019 ◽  
Author(s):  
Cameron S. Cowan ◽  
Magdalena Renner ◽  
Brigitte Gross-Scherf ◽  
David Goldblum ◽  
Martin Munz ◽  
...  
Keyword(s):  
Single Cells ◽  
Pigment Epithelium ◽  
Cell Types ◽  
Retinal Cell ◽  
Human Retina ◽  
Cell Type ◽  
Cell Type Specificity ◽  
Retina Development ◽  
Adult Human

SummaryHow closely human organoids recapitulate cell-type diversity and cell-type maturation of their target organs is not well understood. We developed human retinal organoids with multiple nuclear and synaptic layers. We sequenced the RNA of 158,844 single cells from these organoids at six developmental time points and from the periphery, fovea, pigment epithelium and choroid of light-responsive adult human retinas, and performed histochemistry. Cell types in organoids matured in vitro to a stable ‘developed’ state at a rate similar to human retina development in vivo and the transcriptomes of organoid cell types converged towards the transcriptomes of adult peripheral retinal cell types. The expression of disease-associated genes was significantly cell-type specific in adult retina and cell-type specificity was retained in organoids. We implicate unexpected cell types in diseases such as macular degeneration. This resource identifies cellular targets for studying disease mechanisms in organoids and for targeted repair in adult human retinas.

scholarly journals SCAR is a primary regulator of Arp2/3-dependent morphological events in Drosophila

2002 ◽  
Vol 156 (4) ◽  
pp. 689-701 ◽  
Author(s):  
Jennifer A. Zallen ◽  
Yehudit Cohen ◽  
Andrew M. Hudson ◽  
Lynn Cooley ◽  
Eric Wieschaus ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Morphology ◽  
Actin Polymerization ◽  
Cell Types ◽  
Filamentous Actin ◽  
Cell Fate Decisions ◽  
Cytoplasmic Organization ◽  
Multiple Cell

The Arp2/3 complex and its activators, Scar/WAVE and Wiskott-Aldrich Syndrome protein (WASp), promote actin polymerization in vitro and have been proposed to influence cell shape and motility in vivo. We demonstrate that the Drosophila Scar homologue, SCAR, localizes to actin-rich structures and is required for normal cell morphology in multiple cell types throughout development. In particular, SCAR function is essential for cytoplasmic organization in the blastoderm, axon development in the central nervous system, egg chamber structure during oogenesis, and adult eye morphology. Highly similar developmental requirements are found for subunits of the Arp2/3 complex. In the blastoderm, SCAR and Arp2/3 mutations result in a reduction in the amount of cortical filamentous actin and the disruption of dynamically regulated actin structures. Remarkably, the single Drosophila WASp homologue, Wasp, is largely dispensable for these numerous Arp2/3-dependent functions, whereas SCAR does not contribute to cell fate decisions in which Wasp and Arp2/3 play an essential role. These results identify SCAR as a major component of Arp2/3-dependent cell morphology during Drosophila development and demonstrate that the Arp2/3 complex can govern distinct cell biological events in response to SCAR and Wasp regulation.

scholarly journals Single-cell analysis of human retina identifies evolutionarily conserved and species-specific mechanisms controlling development

2019 ◽  
Author(s):  
Yufeng Lu ◽  
Fion Shiau ◽  
Wenyang Yi ◽  
Suying Lu ◽  
Qian Wu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Cell Fate ◽  
Single Cell Analysis ◽  
Retinal Development ◽  
Cell Types ◽  
Retinal Cell ◽  
Transcriptional Networks ◽  
Species Specific

SummaryThe development of single-cell RNA-Sequencing (scRNA-Seq) has allowed high resolution analysis of cell type diversity and transcriptional networks controlling cell fate specification. To identify the transcriptional networks governing human retinal development, we performed scRNA-Seq over retinal organoid and in vivo retinal development, across 20 timepoints. Using both pseudotemporal and cross-species analyses, we examined the conservation of gene expression across retinal progenitor maturation and specification of all seven major retinal cell types. Furthermore, we examined gene expression differences between developing macula and periphery and between two distinct populations of horizontal cells. We also identify both shared and species-specific patterns of gene expression during human and mouse retinal development. Finally, we identify an unexpected role for ATOH7 expression in regulation of photoreceptor specification during late retinogenesis. These results provide a roadmap to future studies of human retinal development, and may help guide the design of cell-based therapies for treating retinal dystrophies.

scholarly journals Single-cell RNA-seq analysis maps the development of human fetal retina

2018 ◽  
Author(s):  
Yufeng Lu ◽  
Wenyang Yi ◽  
Qian Wu ◽  
Suijuan Zhong ◽  
Zhentao Zuo ◽  
...  
Keyword(s):  
Single Cell ◽  
Visual Information ◽  
Developmental Trajectories ◽  
Retinal Development ◽  
Neuronal Cell ◽  
Cell Types ◽  
Retinal Cell ◽  
Rna Seq ◽  
Fetal Retina ◽  
The Impact

AbstractVision starts with image formation at the retina, which contains diverse neuronal cell types that extract, process, and relay visual information to higher order processing centers in the brain. Though there has been steady progress in defining retinal cell types, very little is known about retinal development in humans, which starts well before birth. In this study, we performed transcriptomic profiling of developing human fetal retina from gestational weeks 12 to 27 using single-cell RNA-seq (scRNA-seq) and used pseudotime analysis to reconstruct the developmental trajectories of retinogenesis. Our analysis reveals transcriptional programs driving differentiation down four different cell types and suggests that Müller glia (MG) can serve as embryonic progenitors in early retinal development. In addition, we also show that transcriptional differences separate retinal progenitor cells (RPCs) into distinct subtypes and use this information to reconstruct RPC developmental trajectories and cell fate. Our results support a hierarchical program of differentiation governing cell-type diversity in the developing human retina. In summary, our work details comprehensive molecular classification of retinal cells, reconstructs their relationships, and paves the way for future mechanistic studies on the impact of gene regulation upon human retinogenesis.

scholarly journals From Clones to Buds and Branches: The Use of Lung Organoids to Model Branching Morphogenesis Ex Vivo

2021 ◽  
Vol 9 ◽  
Author(s):  
Ana Ivonne Vazquez-Armendariz ◽  
Susanne Herold
Keyword(s):  
Cell Fate ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
3D Culture ◽  
Cell Types ◽  
Branching Morphogenesis ◽  
Cell Fate Decisions ◽  
Culture Systems

Three-dimensional (3D) organoid culture systems have rapidly emerged as powerful tools to study organ development and disease. The lung is a complex and highly specialized organ that comprises more than 40 cell types that offer several region-specific roles. During organogenesis, the lung goes through sequential and morphologically distinctive stages to assume its mature form, both structurally and functionally. As branching takes place, multipotent epithelial progenitors at the distal tips of the growing/bifurcating epithelial tubes progressively become lineage-restricted, giving rise to more differentiated and specialized cell types. Although many cellular and molecular mechanisms leading to branching morphogenesis have been explored, deeper understanding of biological processes governing cell-fate decisions and lung patterning is still needed. Given that these distinct processes cannot be easily analyzedin vivo, 3D culture systems have become a valuable platform to study organogenesisin vitro. This minireview focuses on the current lung organoid systems that recapitulate developmental events occurring before and during branching morphogenesis. In addition, we also discuss their limitations and future directions.

scholarly journals The Roles of Chromatin Accessibility in Regulating the Candida albicans White-Opaque Phenotypic Switch

2021 ◽  
Vol 7 (1) ◽  
pp. 37
Author(s):  
Mohammad N. Qasim ◽  
Ashley Valle Arevalo ◽  
Clarissa J. Nobile ◽  
Aaron D. Hernday
Keyword(s):  
Candida Albicans ◽  
Cell Fate ◽  
Cell Types ◽  
Chromatin Accessibility ◽  
Phenotypic Switching ◽  
Phenotypic Switch ◽  
Chromatin Remodelers ◽  
Environmental Signals ◽  
Cell Fate Decisions ◽  
Simple Model System

Candida albicans, a diploid polymorphic fungus, has evolved a unique heritable epigenetic program that enables reversible phenotypic switching between two cell types, referred to as “white” and “opaque”. These cell types are established and maintained by distinct transcriptional programs that lead to differences in metabolic preferences, mating competencies, cellular morphologies, responses to environmental signals, interactions with the host innate immune system, and expression of approximately 20% of genes in the genome. Transcription factors (defined as sequence specific DNA-binding proteins) that regulate the establishment and heritable maintenance of the white and opaque cell types have been a primary focus of investigation in the field; however, other factors that impact chromatin accessibility, such as histone modifying enzymes, chromatin remodelers, and histone chaperone complexes, also modulate the dynamics of the white-opaque switch and have been much less studied to date. Overall, the white-opaque switch represents an attractive and relatively “simple” model system for understanding the logic and regulatory mechanisms by which heritable cell fate decisions are determined in higher eukaryotes. Here we review recent discoveries on the roles of chromatin accessibility in regulating the C. albicans white-opaque phenotypic switch.

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