Modeling an Inherited RPE Disorder With Human Induced Pluripotent Stem Cells

Abstract

Purpose: : The ability of human induced pluripotent stem cells (hiPSCs) to generate specific retinal cell types has recently been established. One highly anticipated use of hiPSCs is as a means to model cell autonomous disease processes. In this study, we sought to generate and characterize a hiPSC line derived from a patient with an RPE-based inherited retinal degenerative disease.

Methods: : hiPSCs were differentiated towards a retinal fate using a previously described method. Within 2 months of differentiation, uniform pigmentation was observed in a significant fraction of hiPSC-derived neurospheres. Pigmented neurospheres were manually isolated, plated on laminin and expanded in the presence of FGF2 and EGF. hiPSC-RPE produced in this manner was compared to human embryonic stem (ES)- and fetal-derived RPE using PCR, ICC and functional assays. To demonstrate the potential of hiPSCs to model human disease, iPS cells were derived from a patient with gyrate atrophy, differentiated into RPE and tested for ornithine aminotransferase (OAT) activity.

Results: : hiPSCs were differentiated towards a retinal fate using a previously described method. Within 2 months of differentiation, uniform pigmentation was observed in a significant fraction of hiPSC-derived neurospheres. Pigmented neurospheres were manually isolated, plated on laminin and expanded in the presence of FGF2 and EGF. hiPSC-RPE produced in this manner was compared to human embryonic stem (ES)- and fetal-derived RPE using PCR, ICC and functional assays. To demonstrate the potential of hiPSCs to model human disease, iPS cells were derived from a patient with gyrate atrophy, differentiated into RPE and tested for ornithine aminotransferase (OAT) activity.

Conclusions: : This study confirms that RPE derived from hiPSCs is similar to that derived from human ES and prenatal sources. Furthermore, patient-specific hiPSCs can be used to produce retinal cell types that retain disease-causing functional defects. As such, hiPSCs should prove useful for studying the pathophysiology of some human retinal diseases, as well as for screening small molecules for therapeutic effects.

Keywords: retinal degenerations: hereditary • retinal pigment epithelium • differentiation