Abstract
Purpose: :
We investigated the differentiation of the undifferentiated cells isolated from neural crest-derived periodontal ligament (PDLUCs) into retinal neurons and whether it can be an alternative source for retinal repair and regeneration.
Methods: :
PDL tissues were obtained from teeth collected from healthy donors, aged 13 to 30, by manual scrapping and digestion with collagenase type I/III. The dissociated cells were cultured in DMEM/F12 supplemented with 10% fetal bovine serum and 2% penicillin/streptomycin for investigation of the expression profiles by imunohistochemistry and RT-PCR. To imitate forebrain development, PDLUCs were exposed to a retinal determination condition, i.e., antagonism of Wnt and BMP signaling, with IGF-1 and bFGF. Their capacity to differentiate into retinal cells was evaluated by expressions of retinal-specific markers using quantitative PCR and confocal double immunofluorescence.
Results: :
Cultured PDLUCs at passages 2 to 5 expressed the mesenchymal and neural crest markers CD90, CD44, p75/NGFR and Nestin, and the embryonic cell antigen SSEA-4. They also expressed mRNA transcripts for Oct4, Sox2, Nanog and c-Myc. Under retinal determination condition, PDLUCs yielded neurospheres within 24 hours with an age-dependent decrease of neurosphere formation. These neurospheres, when plated on matrigel-coated surface, formed neural rosettes and proliferated. On day 20, Pax6 and rhodopsin were increased up to 50 folds. Retina genes RX, DCX and Lhx2 were also significantly up-regulated. Similar observations were made in a parallel experiment using human H9 embryonic stem cells.
Conclusions: :
Neural crest-derived PDLUCs residing in human tooth exhibited properties of cells at embryonic state and the potential to undergo retinal lineage differentiation. They could provide an easily accessible and promising source for retinal cell replacement.
Keywords: retinal degenerations: cell biology