Differential Expression Of Lens Epithelial–derived Growth Factor (LEDGF) During Neuroepithelial Stem Cell Differentiation In The CNS

Abstract

Abstract: : Purpose:Lens epithelial–derived growth factor (LEDGF/p75), a 530 amino acid transcription factor, was originally identified in lens epithelial cells. and may play an important role in lens epithelial cell terminal differentiation. Since lens epithelium and neuroepithelial stem cells (NESC) are epitheliod ectodermal derivatives, we hypothesized that LEDGF/p75 may be expressed in NESC and involved in central nervous system (CNS) cellular differentiation. Methods:Primary neuroepithelial stem cell and neuronal culture, fetal/adult human brain immunohistochemistry, western blot, immunoprecipitation, tryptic digest–mass spectrometry, small interfering RNA (RNAi) analysis. Results:We first examined rodent primary neuronal cell cultures and human fetal brain specimens by western blot, immunocytochemistry, and mass spectrometry. Our results confirmed the expression of LEDGF within specific regions and in discrete cell types within the CNS. Fetal brain demonstrates heavy LEDGF immunostaining in the germinative matrix, a region enriched in NESC. In NESC stem cell culture, we have shown that LEDGF is expressed in multipotent NESC (nestin+, GFAP–/Tuj1–) and newly–differentiated neurons (GFAP–/TuJ1+). LEDGF/p75 appears to be absent in newly–differentiated astrocytes (GFAP+/TuJ1–). LEDGF exhibits cytoplasmic localization in NESC, nuclear localization in newly–differentiated neurons. We have successfully utilized LEDGF RNAi knockdown and have initiated an investigation of the effect of this maneuver on NESC differentiation. Conclusions:These data indicate that LEDGF is present in NESC and newly–differentiated neurons, but absent in newly–differentiated astroglia. These findings suggest may be important in neuronal differentiation and may serve as a critical transcription factor in the CNS.

Keywords: growth factors/growth factor receptors • gene/expression • transcription factors