Friday, October 28, 2011
Hall 1-2 (San Jose Convention Center)
Retinal diseases affect over 12 million Americans. These diseases, such as macular degeneration and retinitis pigmentosa are associated with dysfunctional photoreceptors and/or retinal pigment epithelium (RPE). Thus, an effective strategy may be to replace the damaged retinal cells if they connect to the remaining inner retina. This study investigates the optimization of differentiation of human embryonic stem cells (hESCs) into photoreceptor progenitors before they are co-cultured with hESC-derived RPE. hESCs are differentiated according to modifications of Nistor et al. (2010, Journal of Neuroscience Methods), including delayed hyaluronic acid treatment, longer time in suspension culture, and a change in concentration and treatment time with transcription factors Dkk1 and LeftyA. The current study focuses on variations in exposure time and concentration of ActivinA, Sonic Hedgehog (shh), and FGF-8. Using immunohistochemistry analysis for retinal-specific factors (ret. RX, Chx10, Crx, Nrl), the following parameters were found to direct a high percentage of retinal progenitors: addition of ActivinA from day 7 (versus day 26) and FGF-8 treatment starting day 7. Treatment with shh in the first week did not improve the results from the previous protocol. These parameters can now be used to begin the next tissue culture experiment, which will result in retinal tissue for transplantation into retinal degenerate rats. This can ultimately lead to treatment for retinal degeneration in humans.