The Role of FGF9 in the Production of Neural Retina and RPE in a Pluripotent Stem Cell Model of Early Human Retinal Development

Am J Ophthalmol. 2019 Oct:206:113-131. doi: 10.1016/j.ajo.2019.04.033. Epub 2019 May 10.

Abstract

Purpose: To investigate the role of fibroblast growth factors (FGFs) in the production of neural retina (NR) and retinal pigmented epithelium (RPE) in a human pluripotent stem cell model of early retinal development.

Methods: Human induced pluripotent stem cell (hiPSC) lines from an individual with microphthalmia caused by a functional null mutation (R200Q) in visual system homeobox 2 (VSX2), a transcription factor involved in early NR progenitor cell (NRPC) production, and a normal sibling were differentiated along the retinal and forebrain lineages using an established protocol. Quantitative and global gene expression analyses (microarray and RNAseq) were used to investigate endogenous FGF expression profiles in these cultures over time. Based on these results, mutant and control hiPSC cultures were treated exogenously with selected FGFs and subjected to gene and protein expression analyses to determine their effects on RPE and NR production.

Results: We found that FGF9 and FGF19 were selectively increased in early hiPSC-derived optic vesicles (OVs) when compared to isogenic cultures of hiPSC-derived forebrain neurospheres. Furthermore, these same FGFs were downregulated over time in (R200Q)VSX2 hiPSC-OVs relative to sibling control hiPSC-OVs. Interestingly, long-term supplementation with FGF9, but not FGF19, partially rescued the mutant retinal phenotype of the (R200Q)VSX2 hiPSC-OV model. However, antagonizing FGF9 in wild-type control hiPSCs did not alter OV development.

Conclusions: Our results show that FGF9 acts in concert with VSX2 to promote NR differentiation in hiPSC-OVs and has potential to be used to manipulate early retinogenesis and mitigate ocular defects caused by functional loss of VSX2 activity. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cell Differentiation
  • Cells, Cultured
  • Fibroblast Growth Factor 9 / biosynthesis
  • Fibroblast Growth Factor 9 / genetics*
  • Gene Expression Regulation, Developmental*
  • Humans
  • Immunohistochemistry
  • Induced Pluripotent Stem Cells / cytology*
  • Induced Pluripotent Stem Cells / metabolism
  • Microphthalmos / genetics*
  • Microphthalmos / metabolism
  • Microphthalmos / pathology
  • Phenotype
  • RNA / genetics
  • Retinal Pigment Epithelium / cytology
  • Retinal Pigment Epithelium / growth & development*
  • Retinal Pigment Epithelium / metabolism

Substances

  • FGF9 protein, human
  • Fibroblast Growth Factor 9
  • RNA