Human Retinal Organoids Provide a Suitable Tool for Toxicological Investigations: A Comprehensive Validation Using...

Area of Science:

• Ophthalmology
• Stem Cell Biology
• Toxicology

Background:

• Retinal drug toxicity screening is crucial for developing safe therapies.
• Human pluripotent stem cell-derived retinal organoids (hPSC-ROs) offer a promising in vitro model due to their structural and cellular resemblance to the human retina.
• hPSC-ROs can be generated at scale, facilitating high-throughput screening.

Purpose of the Study:

• To evaluate the utility of hPSC-derived retinal organoids as a screening platform for assessing drug-induced retinal toxicity.
• To compare the toxicological effects of known retinal toxins on hPSC-ROs with existing in vivo and human data.

Main Methods:

• Two human pluripotent stem cell lines were differentiated into retinal organoids, encompassing key retinal cell types and layers.
• Single-cell RNA sequencing (scRNA-Seq) was performed to analyze cell composition and subtype development.
• Retinal organoids were exposed to a panel of known retinal toxins (ketorolac, digoxin, thioridazine, sildenafil, ethanol, methanol) to assess toxicity.

Main Results:

• Exposure to digoxin, thioridazine, and sildenafil induced photoreceptor cell death.
• Digoxin and thioridazine also impacted Müller glia cells and other retinal cell types.
• All tested drugs activated astrocytes, evidenced by neurite outgrowth.
• Light response was maintained, but the number of responsive retinal ganglion cells decreased post-treatment.

Conclusions:

• hPSC-derived retinal organoids effectively recapitulate known retinal drug toxicities observed in clinical and animal studies.
• These organoids provide a robust and reliable in vitro model for preclinical toxicological screening of drugs targeting the retina.
• The findings support the use of hPSC-ROs for ensuring the safety of novel therapeutic agents for retinal diseases.