Identification of retinal homeobox (rax) gene-dependent genes by a microarray approach: The DNA endoglycosylase neil3 is a major downstream component of the rax genetic pathway
DEVELOPMENTAL DYNAMICS
Authors: Pan, Yi; Kelly, Lisa E.; El-Hodiri, Heithem M.
Abstract
BACKGROUNDThe retinal homeobox (rx/rax) gene is a transcription factor expressed in the developing eye field that is necessary for normal eye development. rax is necessary for retinal specification and stem cell development. The genetic program of early retinal development, including rax expression, can be induced in naive ectoderm by activation of insulin-like growth factor (IGF) signaling. We have undertaken a microarray-based approach to identify rax-dependent IGF-induced genes. decoration:We identified 21 IGF-induced genes that exhibit at least a two-fold decrease in expression when rax expression is knocked down. Ten of these genes were expressed in the developing eye, eight were expressed in the ciliary marginal zone of the mature tadpole retina, and four could significantly rescue the rax knockdown phenotype. One of these, the nei endonuclease VIII-like 3 (neil3) gene, rescued the rax knockdown phenotype to a remarkable degree. We found that neil3 is necessary for normal retinal lamination and retinal neuron differentiation. We have identified neil3 as a component of the rax genetic pathway necessary for normal retinal progenitor cell development. neil3 is involved in the base excision DNA repair pathway, suggesting that this pathway is essential for normal rax-dependent progenitor cell development in the mature retina. Developmental Dynamics 247:1199-1210, 2018. (c) 2018 Wiley Periodicals, Inc.
Application of Hanging Drop Culture for Retinal Precursor-Like Cells Differentiation of Human Adipose-Derived Stem Cells Using Small Molecules
JOURNAL OF MOLECULAR NEUROSCIENCE
Authors: Salehi, Hossein; Razavi, Shahnaz; Esfandiari, Ebrahim; Kazemi, Mohammad; Amini, Shahram; Amirpour, Noushin
Abstract
Retinal degenerative diseases lead to blindness due to poorly regenerative potential of the retina. Recently, cell therapy is more considered for degenerative diseases. Autologous mesenchymal stem cells derived from adipose tissue are a suitable source for this purpose. Therefore, we conducted a stepwise efficient method to differentiate human adipose-derived stem cells (hADSCs) into retinal precursor-like cells in vitro. We compared two differentiation protocols, monolayer and hanging drop cultures. Through the defined medium and 3D hanging drop culture method, we could achieve up to 75% retinal precursor gene expression profile (PAX6, RAX, CHX10, and CRX) from hADSCs. By imitation of in vivo development, for direct conversion of stem cells into retinal cells, the suppression of the BMP, Nodal, and Wnt signaling pathways was carried out by using three small molecules. The hADSCs were primarily differentiated into anterior neuroectodermal cells by expression of OTX2, SIX3, and Beta-TUB III and then the differentiated cells were propelled into the retinal cells. According to our data from real-time PCR, RT-PCR, immunocytochemistry, and functional assay, it seems that the hanging drop method improved retinal precursor differentiation yield which these precursor-like cells respond to glutamate neurotransmitter. Regarding the easy accessibility and immunosuppressive properties of hADSCs and more efficient hanging drop method, this study may be useful for future autologous cell therapy of retinal degenerative disorders.