Derivation of Functional Retinal Pigmented Epithelium from Induced Pluripotent Stem Cells

Abstract

Human induced pluripotent stem cells (iPSCs) have great promise for cellular therapy, but it is unclear if they have the same potential as human embryonic stem cells (hESCs) to differentiate into specialized cell types. Ocular cells such as the retinal pigmented epithelium (RPE) are of particular interest because they could be used to treat degenerative eye diseases, including age-related macular degeneration and retinitis pigmentosa. We show here that iPSCs generated using Oct4, Sox2, Nanog, and Lin28 can spontaneously differentiate into RPE cells, which can then be isolated and cultured to form highly differentiated RPE monolayers. RPE derived from iPSCs (iPS-RPE) were analyzed with respect to gene expression, protein expression, and rod outer segment phagocytosis, and compared with cultured fetal human RPE (fRPE) and RPE derived from hESCs (hESC-RPE). iPS-RPE expression of marker mRNAs was quantitatively similar to that of fRPE and hESC-RPE, and marker proteins were appropriately expressed and localized in polarized monolayers. Levels of rod outer segment phagocytosis by iPS-RPE, fRPE, and hESC-RPE were likewise similar and dependent on integrin avb5. This work shows that iPSCs can differentiate into functional RPE that are quantitatively similar to fRPE and hESC-RPE and further supports the finding that iPSCs are similar to hESCs in their differentiation potential.

Stem Cells for Retinal Replacement Therapy

“…iPSCs can be directed to a variety of lineages, including RSCs and RPESCs. iPSC-derived RPE-like cells (iPSC-RPEs) [67][68][69][70] transplanted into the retina show incorporation into the photoreceptor layer with rescue of vision in an animal model [71]. RSCs have also been derived from iPSCs by selecting retinal rosettes [68] or by directing differentiation with small molecules [72].…”

Induced Pluripotent Stem Cell Therapies for Degenerative Disease of the Outer Retina: Disease Modeling and Cell Replacement

“…Production of RPE cells from ESC and iPSC has been established by a number of different laboratories that have developed protocols for generation of homogeneous polarized RPE monolayer cultures. 12,45,46,47 iPSC-derived RPE cells can be isolated, expanded, differentiated, reseeded, and monitored both for morphology and functionality. 48 Also highly significant has been the discovery that iPSC/ ESC are able to self-assemble into three-dimensional (3D) optic cup structures, which then form stratified neural retinal tissues.…”

Efficient Derivation of Retinal Pigment Epithelium Cells from Stem Cells

“…While the reported survival rates of implanted RPE in the subretinal space of RCS rats and mice vary greatly, there is potential for them to survive for several months or years 9,10,12,20 . RPE cells can be obtained in sufficient numbers for transplantation by deriving them from pluripotent stem cells [9][10][11][12][13][14][25][26][27][28] . Several independent groups have demonstrated that these cells function in similar ways to their somatic counterparts, and long term studies suggest that they are safe upon implantation in rat and mouse disease models 9,10,12,14,19,20,25,[29][30][31][32] .…”

“…RPE cells can be obtained in sufficient numbers for transplantation by deriving them from pluripotent stem cells [9][10][11][12][13][14][25][26][27][28] . Several independent groups have demonstrated that these cells function in similar ways to their somatic counterparts, and long term studies suggest that they are safe upon implantation in rat and mouse disease models 9,10,12,14,19,20,25,[29][30][31][32] . The use of induced pluripotent stem cells instead of embryonic stem cells may be advantageous since ethical issues and immunological challenges associated with allogeneic RPE may be obviated 33,34 .…”