Functional Roles of Nurr1, Pitx3, and Lmx1a in Neurogenesis and Phenotype Specification of Dopamine Neurons During In Vitro Differentiation of Embryonic Stem Cells

Abstract

To elucidate detailed functional mechanisms of key fate-determining transcription factors (eg, Nurr1, Pitx3, and Lmx1a) and their functional interplay for midbrain dopamine (mDA) neurons, we developed highly efficient gain-of-function system by transducing the neural progenitors (NPs) derived from embryonic stem cells (ESCs) with retroviral vectors, allowing the analysis of downstream molecular and cellular effects. Overexpression of each factors, Nurr1, Pitx3, and Lmx1a robustly promoted the dopaminergic differentiation of ESC-NP cells exposed to sonic hedgehog (SHH) and fibroblast growth factor 8 (FGF8). In addition, each of these factors directly interacts with potential binding sites within the tyrosine hydroxylase (TH) gene and activated its promoter activity. Interestingly, however, overexpression of Nurr1, but not of Pitx3 or Lmx1a, generated a significant number of nonneuronal TH-positive cells. In line with this, Pitx3 and Lmx1a, but not Nurr1, induced expression of the Ngn2 gene, which is critical for neurogenesis. We also observed that Pitx3 directly bound to its potential binding sites within the Ngn2 gene and the pan-neuronal marker b-tubulin III gene, suggesting that Pitx3 contributes to mDA neurogenesis by directly regulating these genes. Taken together, our data demonstrate that key mDA regulators (Nurr1, Pitx3, and Lmx1a) play overlapping as well as distinct roles during neurogenesis and neurotransmitter phenotype determination of mDA neurons.

Development of stem cell-based therapies for Parkinson's disease

“…Hong and associates have established that overexpression of each factors, Nurr1, Pitx3, and Lmx1a robustly promoted the dopaminergic differentiation of ESC-NP cells exposed to SHH and FGF8 and demonstrated that key midbrain DA (mDA) regulators (Nurr1, Pitx3, and Lmx1a) play overlapping as well as distinct roles during neurogenesis and neurotransmitter phenotype determination of mDA neurons. This further proved the link of generation of DA neurons from ESCs with the overexpression of genes and transcription factors, such as Nurr1, Pitx3 and Lmx1a [27,28]. Human ESCs also display electrophysiological features of DA neurons and most importantly are capable of DA release in vitro whilst demonstrating gene expression.…”

“…Human ESCs also display electrophysiological features of DA neurons and most importantly are capable of DA release in vitro whilst demonstrating gene expression. Several studies have illustrated methods to enhance the generation of DA neurons from human ESCs [28,29]. These findings highlight the necessity for the identification of differentiation and survival mechanisms and the eradication of factors responsible for excessive proliferation, required for protocols for cell replacement therapies today.…”

ReNCell VM conditioned medium enhances the induction of dental pulp stem cells into dopaminergic like cells

“…Furthermore MS1 is involved in stem cell self-renewal and asymmetric cell division which is highly correlated with proliferation, survival and neurogenesis (Pozniak and Pleasure 2006). Additionally NR4A2 was reported as one of major key regulators in dopaminergic neuron formation (Hong et al 2014). PAX6 gene moreover is responsible in survival of immature neurons via CREB-signalling (Faigle and Song 2013).…”

MicroRNAs

“…In concert with Wnt1 and other dopaminergic transcription factors such as Nurr1 and Pitx3, Lmx1a robustly promotes the differentiation of embryonic stem cells to neuroprogenitors expressing dopaminergic markers in vivo (Hong et al, 2014;Joksimovic & Awatramani, 2014). Also, known as a master regulator of mDA differentiation, the ectopic expression of Lmx1a has been exploited to drive the differentiation of stem cells into dopaminergic neurons for transplantation purposes in potential cell therapy strategies for Parkinson's disease (PD) (Wu et al, 2015;Yan et al, 2013).…”