Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University Beijing, China (People's Republic)
Abstract: Human retinal organoids (ROs), derived from human pluripotent stem cells (hPSCs), have been widely applied in disease mechanism researching, drug screening, and cell therapy. However, current ROs exhibit slow photoreceptor maturation and lack a vascular system, preventing them from accurately recapitulating retinal development and limiting their utility in studying retinal vascular diseases and drug screening. Here, we present a novel approach for generating human vascularized retinal organoids (vROs) that exhibit a typical ordered, stratified retinal architecture, comprising multi-layered neurons, and incorporate a functional blood vessel network that remains viable for over 6 months, establishing a robust model for vascularized retinal tissue. We found that, the inclusion of pericytes in vROs facilitated the development of a more elaborate and longer-lasting vascular network, enhancing endothelial cell survival and network stability. Moreover, timely addition of extracellular matrix (ECM) was critical for the proper integration of the vascular network with ROs and ensured the coordinated development of retinal neurons across different layers, with photoreceptor cells being able to extend typical outer segments. Notably, pericytes in vROs surrounded endothelial cells, forming lumen-like structures, and collagen IV deposition was observed around the vascular network. Importantly, single-cell RNA sequencing and immunostaining analyses indicated that vascularization accelerated the maturation of bipolar cells and photoreceptors, which was further supported by electrophysiological assessments. CellChat analysis suggested that the vascular network may promote photoreceptor and bipolar maturation through the IGF signaling pathway. Taken together, we have successfully developed vROs that exhibit typical multi-layered neuronal architecture and earlier photoreceptor maturation, providing a more accurate model for studying the pathogenesis of retinal vascular diseases and advancing drug development.
Funding Source: The National Natural Science Foundation of China (82125007, 81970838, and 82201225), Beijing Municipal Public Welfare Development and Reform Pilot Project for Medical Research Institutes (PWD&RPP-M RI, JYY2023-6).
