No replies to this topic

[Engadin]

S O U R C E :    Stem Cells Portal

 

 

P R I M A L   S O U R C E :   Stem Cells Journals

 

Researchers from the laboratory of Majlinda Lako (Newcastle University, UK) recently reported on the production of photoreceptors from human pluripotent stem cells (hPSCs) previously cultured on mouse embryonic fibroblasts under two-dimensional feeder‐free and three-dimensional organoid culture conditions [1, 2]. However, their subsequent studies employing hPSCs adapted to feeder‐free and defined media conditions encountered different results. Importantly, additional studies have underlined that a single defined protocol for organoid generation does not necessarily function for every hPSC line encountered [3-5].

 

These perplexing findings prompted the team to compare how the retinal organoid differentiation protocol employed and cell background may affect the production of mature and functional photoreceptors. In their new STEM CELLS Translational Medicine article, Mellough et al. now report that cell line‐specific differences and embryoid body generation/organoid maintenance methods both contribute to the differing abilities of hPSCs to produce laminated retinal tissue containing mature and electrophysiologically responsive photoreceptors [6]. 

 

Can this comparative study highlight the optimal means to produce mature and functional retinal cell types?

 

Employing transcriptional analysis during the first five weeks of differentiation, the authors discovered that the hPSC-type used represented the most critical variable affecting early differentiation efficiency rather than the specific differentiation method employed. However, later differentiation and maturation of retinal organoids over 22 weeks depended on the embryoid body generation method used and the particular maintenance conditions. 

 

Overall, the study highlighted that the mechanical method of embryoid body generation under static conditions, followed by Rho-associated protein kinase inhibitor treatment for the first 48 hours of differentiation, and subsequent organoid maintenance under stationary culture conditions provided for the consistent formation of laminated retinal neuroepithelium containing mature and electrophysiologically responsive photoreceptors that closely resembled human embryonic/fetal retina.

 

In summary, the authors highlight the specific contributions of cell line‐specific differences and embryoid body generation/organoid maintenance methods in the production of laminated retinae. Furthermore, they anticipate that a greater understanding of the events controlling retinal organoid formation will allow the development of improved and standardized protocols for large scale production of, for example, electrophysiologically sensitive photoreceptors from an hPSC line for applications in ophthalmic research and development.