Transdifferentiation of periodontal ligament-derived stem cells into retinal ganglion-like cells and its microRNA signature.

Tsz Kin Ng,Herman S Cheung,Kwong Wai Choy,Christopher K S Leung,Di Cao,Chi Pui Pang,Jasmine S Y Yung

doi:10.1038/srep16429

Abstract

Retinal diseases are the leading causes of irreversible visual impairment and blindness in the developed countries. Human retina has limited regenerative power to replace cell loss. Stem cell replacement therapy has been proposed as a viable option. Previously, we have induced human adult periodontal ligament stem cells (PDLSCs) to the retinal lineage. In this study, we modified our induction protocol to direct human adult PDLSCs into retinal ganglion-like cells and determined the microRNA (miRNA) signature of this transdifferentiation process. The differentiated PDLSCs demonstrated the characteristics of functional neurons as they expressed neuronal and retinal ganglion cell markers (ATOH7, POU4F2, β-III tubulin, MAP2, TAU, NEUROD1 and SIX3), formed synapses and showed glutamate-induced calcium responses as well as spontaneous electrical activities. The global miRNA expression profiling identified 44 upregulated and 27 downregulated human miRNAs after retinal induction. Gene ontology analysis of the predicted miRNA target genes confirmed the transdifferentiation is closely related to neuronal differentiation processes. Furthermore, the expressions of 2 miRNA-targeted candidates, VEGF and PTEN, were significantly upregulated during the induction process. This study identified the transdifferentiation process of human adult stem cells into retinal ganglion-like cells and revealed the involvement of both genetic and miRNA regulatory mechanisms.

Highlights

Leads to the establishment of various protocols on the induction of embryonic stem cells (ESCs) into retinal lineage[3,4,5,6]
Immunofluorescence signals of β -III tubulin, MAP2, TAU, POU4F2, NEUROD1 and SIX3 were detected in the induced periodontal ligament-derived stem cells (PDLSCs) (Fig. 2A). 30–52% of the induced cells displayed the expression of these retinal and neuronal markers (Fig. 2B)
Adult stem cell-derived retinal cells have not been attempted for use in cell replacement therapy

Summary

Introduction

Leads to the establishment of various protocols on the induction of embryonic stem cells (ESCs) into retinal lineage[3,4,5,6]. Similar induction capability applies to induced pluripotent stem cells (iPSCs)[7]. We reported that the human adult periodontal ligament-derived stem cells (PDLSCs) are capable of differentiating into the neurogenic, cardiomyogenic, chondrogenic and osteogenic lineages[10]. We modified the induction protocol to generate RGC-like cells with electrophysiological functions. The gene expression profile of retinal induction has only been reported using ESCs12, whereas the miRNA expression profiles only limited to the differentiation of ESCs and iPSCs into retinal pigment epithelial (RPE) cells[13,14,15]. In this study, determined the RGC marker expression, the glutamate-induced calcium response as well as the electrophysiology of the differentiated PDLSCs. the miRNA expression profile of retinal induction on human adult PDLSC was identified using microarray platform. The expression of predicted miRNA targets was evaluated

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