Modeling human retinal development with patient-specific induced pluripotent stem cells reveals multiple roles for visual system homeobox 2.

Abstract

Human induced pluripotent stem cells (hiPSCs) have been shown to differentiate along the retinal lineage in a manner that mimics normal mammalian development. Under certain culture conditions, hiPSCs form optic vesicle-like structures (OVs), which contain proliferating progenitors capable of yielding all neural retina (NR) cell types over time. Such observations imply conserved roles for regulators of retinogenesis in hiPSC-derived cultures and the developing embryo. However, whether and to what extent this assumption holds true has remained largely uninvestigated. We examined the role of a key NR transcription factor, visual system homeobox 2 (VSX2), using hiPSCs derived from a patient with microphthalmia caused by an R200Q mutation in the VSX2 homeodomain region. No differences were noted between (R200Q)VSX2 and sibling control hiPSCs prior to OV generation. Thereafter, (R200Q)VSX2 hiPSC-OVs displayed a significant growth deficit compared to control hiPSC-OVs, as well as increased production of retinal pigmented epithelium at the expense of NR cell derivatives. Furthermore, (R200Q)VSX2 hiPSC-OVs failed to produce bipolar cells, a distinctive feature previously observed in Vsx2 mutant mice. (R200Q)VSX2 hiPSC-OVs also demonstrated delayed photoreceptor maturation, which could be overcome via exogenous expression of wild-type VSX2 at early stages of retinal differentiation. Finally, RNAseq analysis on isolated hiPSC-OVs implicated key transcription factors and extracellular signaling pathways as potential downstream effectors of VSX2-mediated gene regulation. Our results establish hiPSC-OVs as versatile model systems to study retinal development at stages not previously accessible in humans and support the bona fide nature of hiPSC-OV-derived retinal progeny.

• Authors: M Joseph Phillips, Enio T Perez, Jessica M Martin, Samantha T Reshel, Kyle A Wallace, Elizabeth E Capowski, Ruchira Singh, Lynda S Wright, Eric M Clark, Patrick M Barney, Ron Stewart, Sarah J Dickerson, Michael J Miller, E Ferda Percin, James A Thomson, David M Gamm
• Journal: Stem cells (Dayton, Ohio) (Stem Cells) Vol. 32 Issue 6 Pg. 1480-92 (Jun 2014) ISSN: 1549-4918 [Electronic] England
• PMID: 24532057 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 AlphaMed Press.

Chemical References

• Homeodomain Proteins
• Transcription Factors
• VSX2 protein, human

Topics

• Adult
• Amino Acid Substitution
• Animals
• Body Patterning (genetics)
• Cell Differentiation
• Cell Line
• Cell Lineage
• HEK293 Cells
• Homeodomain Proteins (genetics, metabolism)
• Humans
• Induced Pluripotent Stem Cells (metabolism)
• Male
• Mice
• Models, Biological
• Mutation (genetics)
• Phenotype
• Photoreceptor Cells (metabolism, pathology)
• Retina (embryology, metabolism, pathology)
• Retinal Bipolar Cells (metabolism, pathology)
• Retinal Pigment Epithelium (embryology, pathology)
• Sequence Analysis, RNA
• Signal Transduction (genetics)
• Transcription Factors (genetics, metabolism)
• Transcriptome (genetics)