Protocols for generating 3D neural retina (NR) organoids from human pluripotent stem cells (hPSCs) are capable of producing laminated tissues during early differentiation, with later development of highly organized outer NR structures. However, over time inner NR laminae are often lost and/or become disorganized, beginning with the retinal ganglion cell layer. A likely explanation for the selective survival of the outer NR in organoids lies in the dual blood supply of the retina, where the outer NR is fed via diffusion while the inner NR requires a separate microvasculature that is absent in organoids. We propose to address this disparity in outer vs. inner NR survival and function in vitro by incorporating a perfusable inner retinal microvasculature using hPSC-derived vascular progenitor cells and microfluidic technology. Similar strategies were employed by members of our group to vascularize forebrain organoids and perform screens for toxic agents, which is amenable to scale up for high throughput assay development. Besides the potential to maintain inner NR, a major advantage of our approach is the capacity to model retinal microvascular diseases such as diabetic retinopathy (DR), one of the leading causes of vision loss in the U.S. Physiologically relevant functional readouts for the resulting full thickness, vascularized NR organoids will include electrophysiological recordings, metabolic and functional imaging, and perfusate analysis. If successful, our approach may also address other shortcomings of current organoid culture methods, including low production efficiencies and high inter-organoid variability, which further hinder their practical use for therapeutic and toxicological screening. Our UW-based team of stem cell biologists, bioengineers, tissue imagers, electrophysiologists, and vascular retinopathy model experts is well-suited for this challenge, and our association with leading hiPSC tools manufacturers (Cellular Dynamics International and StemPharm) and a retinal cell therapeutic developer (Opsis Therapeutics) offer future avenues for industrial scale-up and quality systems assurance.
Solution for: NEI 3-D Retina Organoid Challenge (3-D ROC)
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