Accelerate your lead compound selection by understanding their mode of action in functional retinal tissue
1.
Recapitulate the architecture and function of the human retina
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Evaluate novel drugs safety profile in vitro
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Accelerate drug discovery & replace animal experiments
Accelerated in vitro evaluation of retinal toxicity
Newcells offers a fast and reliable retinal drug toxicity in vitro testing service using complex retinal organoids models developed in house or generated from cells supplied by the client. The retinal toxicity service evaluates how new compounds affect cell viability, following photoreceptor degeneration. We also offer the comparison of several time points during differentiation. Our retinal toxicity service is fast, giving our clients insights into the ocular toxicity profile of their compounds and allowing them to evaluate possible rescue strategies.
Service outputs
Rapid retinal toxicity evaluation of compounds in iPSC-derived retinal organoids
Qualitative immunofluorescence on frozen retinal organoid sections using key markers
Time point comparisons
Assessment of the composition of retinal ganglion cells, photoreceptors, amacrine, horizontal cells and Muller glia using imaging techniques
Compound effect on PRE barrier, phagocytic integrity, viability, ultrastructure, protein and gene expression
What is retinal toxicity and how can it be evaluated in vitro? Some drugs administered systematically may affect the function of the retina. Similarly, new treatments for eye diseases require careful safety evaluation. Retinal toxicity studies can be performed in animal models, or human ex-vivo models. However, these are limiting due to the number of experimental data points generated and limited predictivity in humans.
Newcells scientists have developed robust human iPSC-derived retinal tissue models. Retinal organoids are obtained through a carefully controlled differentiation process recapitulating the timeline of embryonic retinogenesis. At day 150, the organoids comprise all key cell types and are functional, allowing the evaluation of the cytotoxic effect of new compounds by simply adding them to the plate. The cell structure integrity and the gene expression profiles of key markers for the main cell types, such as photoreceptors, are then assessed. We also perform qualitative imaging and microscopy to provide a comprehensive drug toxicity profile. As our models are derived from human iPSCs, they are directly relevant to human clinical trials, and provide key data for transitional studies. The two main advantages of using in vitro retinal toxicity testing are the speed (as most simple studies can be carried out within one to two months) and the predictivity for human clinical trials.
These studies can be carried out in our retinal organoids in vitro models for rapid evaluation of retinal toxicity of new compounds.
Modelling retinal drug toxicity: Retinal organoids have been tested for the response of known toxins such as thioridazine and doxorubicin. The intrinsic fluorescence of doxorubicin facilitates visualisation of the drug penetrating the retinal organoid (A). Exposure of the iPSC-derived retinal organoids to doxorubicin reduces cell viability in a dose-dependent manner (B).
(A) Newcells’ human iPSC-derived retinal organoids are permeable to small molecules. The penetration of doxorubicin, a naturally fluorescent small toxic molecule (red), into the retinal organoids increases over time (4h to 24h) demonstrating the permeability of the organoids to drugs.
(B) The retinal organoids were treated with increasing dose of doxorubicin over a period of 24h and cell viability was measured using an ATP assay. A dose-dependent decrease in cell viability was observed following increasing exposure to the drug.
During early drug development, drug screening is an essential step for the identification of lead compounds. This is usually performed as medium to high throughput. Newcells Biotech retinal organoids are suitable for in vitro drug screening since they are generated every 4-6 weeks (on-demand supply) in a 96-well plate format. They have been used to distinguish compounds which are toxic and non-toxic to the retina.
Dose-response plots of known cytotoxic and non-cytotoxic retinal agents. Retinal organoids were exposed to increasing concentrations of either cytotoxic or non-cytotoxic drugs and cell viability was measured over time. As expected, cell viability decreased upon increasing addition of Thioridazine and 4-hydrohytamoxifen, whilst non-cytotoxic drugs had no effect. The dose-response of cytotoxic and non-cytotoxic retinal agents was determined using CellTiter-Glo® 3D ATP assay.
Newcells provides a custom service evaluating retinal toxicity using our complex iPSC-derived human retinal models (retinal organoids)
Even though the differentiation process of retinal organoids is up to 210 days, our streamlined manufacturing process releases regular supply of tissue supporting short projects timelines. The robust data generated by our scientific experts will guide you in confidence for key decision-making steps during drug development.
An example of retinal drug toxicity screening includes a set of assays to assess cell viability, photoreceptor functionality and degeneration as well as key marker expression and localisation. We can also assess the safety of new viral vectors such as AAV.
Assay design
Models
Retinal organoids with photoreceptors (cone and rod), retinal ganglion cells, horizontal cells and amacrine cells (WT).
Assay format
96-well plates (retinal organoids)
Species
Human
Assay readout
Cell viability assay (ATP depletion assay, LDH release and microscopy)
Qualitative immunofluorescence with cell specific markers & apoptosis markers
Gene expression profile of key marker gene by RT-qPCR
Microscopy: 2D-TEM and SEM
Time points and replicates
Retinal organoids toxicity service can be performed at any time point of differentiation up to Day 210.
Data points are usually performed in triplicates or quadruples with a minimum of 10 organoids.
The retinal organoids are iPSC-derived, and they recapitulate the complex structure of the human retina with laminar cell organisation mimicking embryonic development. They contain the outer photoreceptor segment of the retina that responds to light.
Cone photoreceptor cells labelled with anti-Opsin (Red/Green) antibody.Find out more
Retinal pigment epithelium
A functional 2D in vitro model of retinal pigment epithelial cells generated from human iPSCs recapitulating phagocytosis of photoreceptor outer segments. The RPE cells are pigmented and displays typical cobblestone morphology.
RPE cells displaying cobblestone morphology. Cells were immunolabeled with tight-junction ZO-1 marker (shown in green) and co-stained with nuclei marker, Hoechst (shown in blue).Read more
