Enhancing the efficiency of direct reprogramming of human primary fibroblasts into dopaminergic neuron-like cells through p53 suppression.

Qian Huang,Chuan-Yuan Li,Fang Li,Xinjian Liu

doi:10.1007/s11427-014-4730-2

Abstract

Dopaminergic (DA) neuron-like cells obtained through direct reprogramming of primary human fibroblasts offer exciting opportunities for treatment of Parkinson's disease. A significant obstacle is the low efficiency of conversion during the reprogramming process. Here, we demonstrate that the suppression of p53 significantly enhances the efficiency of transcription factor-mediated conversion of human fibroblasts into functional dopaminergic neurons. In particular, blocking p53 activity using a dominant-negative p53 (p53-DN) in IMR90 cells increases the conversion efficiency by 5-20 fold. The induced DA neuron-like cells exhibit dopamine neuron-specific gene expression, significant dopamine uptake and production capacities, and enables symptomatic relief in a rat Parkinson's disease model. Taken together, our findings suggest that p53 is a critical barrier in direct reprogramming of fibroblast into dopaminergic neurons.

Highlights

Parkinson’s disease (PD) is a chronic and progressive movement disorder, which involves the selective loss of midbrain dopamine neurons
In our own published study [11], we show that a combination of five transcriptional factors Mash1, Ngn2, Sox2, Nurr1, and Pitx3 could directly reprogram human fibroblasts into dopaminergic neuron cells
Direct reprogramming of somatic cells into dopaminergic neurons provides an alternative source of DA neurons that significantly reduce the carcinogenic risks inherent in the induced pluripotent stem cells (iPSCs)-differentiation approach

Summary

Introduction

Parkinson’s disease (PD) is a chronic and progressive movement disorder, which involves the selective loss of midbrain dopamine neurons. The conversion efficiency ranged from 1.8% to 7.7% in MEFs. Caiazzo et al [9] demonstrated a combination of three factors, Mash, Nurr and Lmx1a, that were able to generate functional dopaminergic neurons directly from mouse and human fibroblasts. In our own published study [11], we show that a combination of five transcriptional factors Mash, Ngn, Sox, Nurr, and Pitx could directly reprogram human fibroblasts into dopaminergic neuron cells. We observed that during the reprogramming process, most human fibroblast (IMR90) cells died from detachment and sloughing off, which was the main reason leading to low conversion efficiency. It has been shown that p53 and several other tumor genes are significant barriers for the induction of iPSC [15 19] We reasoned that it may play a similar role in reprogramming human fibroblasts into DA neurons. Its inhibition may lead to increased efficiency of deriving DA neurons through direct reprogramming

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