Human stem cell-based retina on chip as new translational model for validation of AAV retinal gene therapy vectors

Abstract

Gene therapies using adeno-associated viruses (AAVs) are among the most promising strategies to treat or even cure hereditary and acquired retinal diseases. However, the development of new efficient AAV vectors is slow and costly, largely because of the lack of suitable non-clinical models. By faithfully recreating structure and function of human tissues, human induced pluripotent stem cell (iPSC)derived retinal organoids could become an essential part of the test cascade addressing translational aspects. Organ-on-chip (OoC) technology further provides the capability to recapitulate microphysiological tissue environments as well as a precise control over structural and temporal parameters. By employing our recently developed retina on chip that merges organoid and OoC technology, we analyzed the efficacy, kinetics, and cell tropism of seven first-and second-generation AAV vectors. The presented data demonstrate the potential of iPSC-based OoC models as the next generation of screening platforms for future gene therapeutic studies.

Deciphering the Retinal Epigenome during Development, Disease and Reprogramming: Advancements, Challenges and Perspectives

“…Current considerations for viral vector design and eligibility for pre-clinical trials include retinal tropism, choice of serotype, DNA packaging capacity and transduction efficiency in the cell type of interest, persistence of gene expression, risk of host genome integration, reduced immunogenicity, and off-target effects [ 253 , 258 , 259 ].…”

A Microfluidic Eye Facsimile System to Examine the Migration of Stem-like Cells

“…Microfluidic technologies are well-suited for the study of retinal degenerative diseases, as well as the development of novel therapies, by developing models that mimic the physiological environment at the retinal microscale. Organ-on-a-chip platforms (reviewed in [ 61 , 62 ]) have been recently developed by multiple groups using retinal stem and progenitor cells (SCs) [ 63 , 64 , 65 , 66 ] or organoids [ 67 , 68 , 69 , 70 ] to recapitulate the retinal cellular niche in both healthy and disease states. Some existing systems use 3D, organotypic systems that integrate explanted retina to measure tissue viability and cytotoxicity [ 71 ], while others examine the delivery of therapeutic compounds [ 41 , 42 ].…”

Organoid transduction using recombinant adeno‐associated viral vectors: Challenges and opportunities

“…As of December 2021, there are several publications describing the results of experiments on transduction of organoids derived from lungs, [85] retina, [44,86,87] brain, [88][89][90] intestine, [43] and liver [91] using rAAV vectors. The studies revealed a number of limitations associated with the specifics of cultivation and the cellular composition of organoids, which can obstruct their effective transduction.…”

“…At the same time, some types of organoids, such as retinal ones, can be cultured in a liquid medium without matrix support. In this case, no additional manipulations are required for the rAAV transduction, [86,87,104] the viral vector preparation is introduced directly into the culture medium.…”

“…HSPG is one of the key receptors for natural serotypes of AAV; it is most abundant in nervous tissue and is involved in the formation of neural networks in the retina. [105] The expression of these receptors explains the high tropic properties of rAAV2-7m8, [86,87] a mutant recombinant virus vector constructed by modifying the capsids of serotypes 2, 8, and 9 by inserting oligopeptide 7m8 into the viral capsid. On the other hand, despite the presence of HSPG which serves as a receptor for AAV2 and AAV6, [106] transduction with vectors rAAV2 and ShH10 (AAV6 with capsid mutations I319V, N451D, D532N, and H642N) was significantly less efficient than with rAAV2-7m8, which may be explained by the higher penetration rate of the mutant serotype compared to its parental serotype.…”