Human retinal organoids release extracellular vesicles that regulate gene expression in target human retinal progenitor cells

Abstract

The mechanisms underlying retinal development have not been completely elucidated. Extracellular vesicles (EVs) are novel essential mediators of cell-to-cell communication with emerging roles in developmental processes. Nevertheless, the identification of EVs in human retinal tissue, characterization of their cargo, and analysis of their potential role in retina development has not been accomplished. Three-dimensional retinal tissue derived from human induced pluripotent stem cells (hiPSC) provide an ideal developmental system to achieve this goal. Here we report that hiPSC-derived retinal organoids release exosomes and microvesicles with small noncoding RNA cargo. EV miRNA cargo-predicted targetome correlates with Gene Ontology (GO) pathways involved in mechanisms of retinogenesis relevant to specific developmental stages corresponding to hallmarks of native human retina development. Furthermore, uptake of EVs by human retinal progenitor cells leads to changes in gene expression correlated with EV miRNA cargo predicted gene targets, and mechanisms involved in retinal development, ganglion cell and photoreceptor differentiation and function.

The RNA content of extracellular vesicles fromPRPF31+/−hiPSC-RPE show potential as biomarkers of retinal degeneration

“…These studies can also help inform future studies on the potential of intercellular signaling via EVs in the RPE. It has been previously demonstrated that mRNAs and miRNAs can be transferred via EVs and in turn regulate gene expression of recipient cells (37)(38)(39)(40)(41). Flores-Bellver et al performed an experiment where EVs from GFP-expressing RPE cells were incubated to non-GFP RPE cells and upon uptake of the EVs, the recipient cells expressed GFP, indicating that RPE can functionally uptake EVs and their protein contents (32).…”

Biophysical, Molecular and Proteomic profiling of Human Retinal Organoids derived Exosomes

“…This is one amongst the first study to characterize the protein cargo of retinal organoid-derived EVs using a PBS-vertical wheel bioreactor. A recent study by Zhou et al demonstrated the release of EVs in the conditioned medium and comprehensively characterized the genetic cargo of EVs from three developing time-point of 3D human retinal organoids (D42, D63, and D90) [29]. Uptake of the EVs secreted by the retinal progenitor cells in the early time-point retinal organoids has shown to regulate the gene expression of early differentiated retinal cell types including ganglion cells, amacrine cells, horizontal cells and photoreceptor progenitors and precursors.…”

“…Zhou et al recently published a study which demonstrated that the functional 3D retinal organoids continually generated EVs containing molecular cargo and are linked to post-translational modification and human retinal development regulation [29]. Further it was suggested that EVs may transport their miRNA cargo to human retinal progenitor cells (hRPCs) and the expected targets involved in different stages of retinal development were also studied.…”

“…According to this study, the internalization of 3D retinal organoid EVs by hRPCs and active transport throughout cytoplasmic compartments resulted in the control of gene expression. While their study characterized the small RNA and miRNA profiles of EVs secreted by retinal organoids, no protein cargo was reported [29]. In addition, the dynamic culture environment in PBS VW bioreactor system [65] used in our study promotes nutrient/oxygen transfer as well as EV biogenesis, in comparison to the static retinal organoid cultures used in the literature.…”

“…However, studies to elucidate the biogenesis of EVs from retinal organoids [29] is relatively a new area of interest in exosome theranostics [30]. EVs produced by different cell types or conditions may differ in their content and have varying effects on their target tissues.…”