Abstract
Understanding the mechanisms in the generation of neural stem cells from pluripotent stem cells is a fundamental step towards successful management of neurodegenerative diseases in translational medicine. Albeit all-trans retinoic acid (RA) has been associated with axon outgrowth and nerve regeneration, the maintenance of differentiated neurons, the association with degenerative disease like Parkinson's disease, and its regulatory molecular mechanism from pluripotent stem cells to neural stem cells remain fragmented. We have previously reported that RA is capable of differentiation of human trophoblast stem cells to dopamine (DA) committed progenitor cells. Intracranial implantation of such neural progenitor cells into the 6-OHDA-lesioned substantia nigra pars compacta successfully regenerates dopaminergic neurons and integrity of the nigrostriatal pathway, ameliorating the behavioral deficits in the Parkinson's disease rat model. Here, we demonstrated a dynamic molecular network in systematic analysis by addressing spatiotemporal molecular expression, intracellular protein-protein interaction and inhibition, imaging study, and genetic expression to explore the regulatory mechanisms of RA induction in the differentiation of human trophoblast stem cells to DA committed progenitor cells. We focused on the tyrosine receptor kinase (Trk), G proteins, canonical Wnt2B/β-catenin, genomic and non-genomic RA signaling transductions with Tyrosine hydroxylase (TH) gene expression as the differentiation endpoint. We found that at the early stage, integration of TrkA and G protein signalings aims for axonogenesis and morphogenesis, involving the novel RXRα/Gαq/11 and RARβ/Gβ signaling pathways. While at the later stage, five distinct signaling pathways together with epigenetic histone modifications emerged to regulate expression of TH, a precursor of dopamine. RA induction generated DA committed progenitor cells in one day. Our results provided substantial mechanistic evidence that human trophoblast stem cell-derived neural stem cells can potentially be used for neurobiological study, drug discovery, and as an alternative source of cell-based therapy in neurodegenerative diseases like Parkinson's disease.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Axons / metabolism
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Calcium Signaling
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Calcium-Calmodulin-Dependent Protein Kinase Type 2 / metabolism
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Cell Differentiation* / drug effects
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Cell Differentiation* / genetics
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Cell Line
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Cyclic AMP Response Element-Binding Protein / genetics
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Cyclic AMP Response Element-Binding Protein / metabolism
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Disease Models, Animal
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Dopaminergic Neurons / cytology*
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GTP-Binding Proteins / metabolism*
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Gene Expression Regulation
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Glycogen Synthase Kinase 3 / metabolism
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Homeodomain Proteins / metabolism
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Humans
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Models, Biological
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Morphogenesis
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Multiprotein Complexes / metabolism
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Nuclear Pore Complex Proteins / metabolism
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Parkinson Disease / genetics
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Parkinson Disease / metabolism
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Protein Binding
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Protein Transport
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Proto-Oncogene Proteins c-akt / metabolism
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Rats
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Receptor, trkA / metabolism*
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Receptors, Retinoic Acid / metabolism
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Retinoid X Receptor alpha / metabolism
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Signal Transduction* / drug effects
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Stem Cells / cytology*
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Stem Cells / drug effects
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Stem Cells / metabolism*
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TOR Serine-Threonine Kinases / metabolism
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Transcription Factors / metabolism
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Trophoblasts / cytology*
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Tyrosine 3-Monooxygenase / genetics
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Tyrosine 3-Monooxygenase / metabolism
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beta Catenin / metabolism
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tau Proteins / metabolism
Substances
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CREB1 protein, human
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Cyclic AMP Response Element-Binding Protein
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Homeodomain Proteins
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MAPT protein, human
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Multiprotein Complexes
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NUP214 protein, human
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Nuclear Pore Complex Proteins
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Receptors, Retinoic Acid
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Retinoid X Receptor alpha
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Transcription Factors
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beta Catenin
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homeobox protein PITX3
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retinoic acid receptor beta
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tau Proteins
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Tyrosine 3-Monooxygenase
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Receptor, trkA
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Proto-Oncogene Proteins c-akt
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TOR Serine-Threonine Kinases
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Calcium-Calmodulin-Dependent Protein Kinase Type 2
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Glycogen Synthase Kinase 3
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GTP-Binding Proteins
Grants and funding
The work was supported by Taiwan Ministry of Science and Technology (
www.most.gov.tw), 101-2811-B-037 -024, EMT, and Kaohsiung Medical University (
www.kmu.edu.tw), 101-1R27, EMT. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. This study was also supported by Accelerated Biosciences Corp. (
www.acceleratedbio.com), AB-0001, JNL. Accelerated Biosciences Corp. provided support in the form of a salary for author TTYL, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific role of this author is articulated in the “author contributions” section.