title: Efficient derivation of dopaminergic neurons from SOX1⁻ floor plate cells under defined culture conditions.
abstract: BACKGROUND
  Parkinson's disease (PD) is a severe neurodegenerative disease associated with loss of dopaminergic neurons. Derivation of dopaminergic neurons from human embryonic stem cells (hESCs) could provide new therapeutic options for PD therapy. Dopaminergic neurons are derived from SOX(-) floor plate (FP) cells during embryonic development in many species and in human cell culture in vitro. Early treatment with sonic hedgehog (Shh) has been reported to efficiently convert hESCs into FP lineages.
  
  
  METHODS
  In this study, we attempted to utilize a Shh-free approach in deriving SOX1(-) FP cells from hESCs in vitro. Neuroectoderm conversion from hESCs was achieved with dual inhibition of the BMP4 (LDN193189) and TGF-β signaling pathways (SB431542) for 24 h under defined culture conditions.
  
  
  RESULTS
  Following a further 5 days of treatment with LDN193189 or LDN193189 + SB431542, SOX1(-) FP cells constituted 70-80 % of the entire cell population. Upon treatment with Shh and FGF8, the SOX1(-) FP cells were efficiently converted to functional Nurr1(+) and TH(+) dopaminergic cells (patterning), which constituted more than 98 % of the entire cell population. However, when the same growth factors were applied to SOX1(+) cells, only less than 4 % of the cells became Nurr1(+), indicating that patterning was effective only if SOX1 expression was down-regulated. After transplanting the Nurr1(+) and TH(+) cells into a hemiparkinsonian rat model, significant improvements were observed in amphetamine induced ipslateral rotations, apomorphine induced contra-lateral rotations and Rota rod motor tests over a duration of 8 weeks.
  
  
  CONCLUSIONS
  Our findings thus provide a convenient approach to FP development and functional dopaminergic neuron derivation.
authors.affiliation: Faculty of Dentistry, National University of Singapore, Kent Ridge, Singapore.
authors.forename: Mingming
authors.initials: M
authors.lastname: Li
authors.affiliation: Faculty of Dentistry, National University of Singapore, Kent Ridge, Singapore.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zou
authors.affiliation: Faculty of Dentistry, National University of Singapore, Kent Ridge, Singapore.
authors.forename: Qiqi
authors.initials: Q
authors.lastname: Lu
authors.affiliation: Department of Pharmacology, Yong Loo Lin School of Medicine, The National University of Singapore, Kent Ridge, Singapore.|Neurobiology and Ageing Programme, Life Sciences Institute of the National University of Singapore, Kent Ridge, Singapore.|Singapore Institute for Neurotechnology (SINAPSE), The National University of Singapore, Kent Ridge, Singapore.
authors.forename: Ning
authors.initials: N
authors.lastname: Tang
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Alexis
authors.initials: A
authors.lastname: Heng
authors.affiliation: Faculty of Dentistry, National University of Singapore, Kent Ridge, Singapore.
authors.forename: Intekhab
authors.initials: I
authors.lastname: Islam
authors.affiliation: Faculty of Dentistry, National University of Singapore, Kent Ridge, Singapore.
authors.forename: Huei Jinn
authors.initials: HJ
authors.lastname: Tong
authors.affiliation: Department of Pharmacology, Yong Loo Lin School of Medicine, The National University of Singapore, Kent Ridge, Singapore.|Neurobiology and Ageing Programme, Life Sciences Institute of the National University of Singapore, Kent Ridge, Singapore.|Singapore Institute for Neurotechnology (SINAPSE), The National University of Singapore, Kent Ridge, Singapore.|National University of Singapore Graduate School for Integrative Sciences and Engineering (NGS), Kent Ridge, Singapore.
authors.forename: Gavin S
authors.initials: GS
authors.lastname: Dawe
authors.affiliation: Faculty of Dentistry, National University of Singapore, Kent Ridge, Singapore. tong_cao@nuhs.edu.sg.|Tissue Engineering Program, Life Sciences Institute of the National University of Singapore, Kent Ridge, Singapore. tong_cao@nuhs.edu.sg.|National University of Singapore Graduate School for Integrative Sciences and Engineering (NGS), Kent Ridge, Singapore. tong_cao@nuhs.edu.sg.
authors.forename: Tong
authors.initials: T
authors.lastname: Cao
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D059290:Dopaminergic Neurons / Q000378:metabolism*; D061252:Feeder Cells / Q000201:enzymology*; D000066449:Human Embryonic Stem Cells / Q000378:metabolism*; D006801:Humans; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D055748:SOXB1 Transcription Factors
chemical_list: C490906:SOX1 protein, human; D055748:SOXB1 Transcription Factors; C098693:Sox1 protein, mouse; C490908:Sox1 protein, rat