Midbrain dopaminergic neuron fate specification of pluripotent stem cells
Author(s)
Jaeger, Ines
Type
Thesis
Abstract
Disorders of dopaminergic neurons in the midbrain are associated with various brain
diseases such as Parkinson’s disease (PD), for which there are no effective treatments.
Pluripotent stem cells (PSCs) offer a remarkable potential for finding new therapeutic
strategies because they are self-renewable and capable to differentiate into all cell types.
However, biomedical applications of PSCs require knowledge of the molecular mechanisms
directing PSCs into midbrain dopaminergic (mDA) cell fate.
During development the generation of mDA neurons is induced by the extrinsic molecules
SHH, FGF8 and WNT1 in the caudal region of the Otx2 positive domain, which marks the
presumptive fore- and midbrain, and rostrally to the future hindbrain expressing Gbx2.
In this study I have further investigated the role of FGF signalling in the generation of mDA
neurons. Here, I have used mouse epiblast stem cells (EpiSCs). Based on their
developmentally primed pluripotent state, we assumed that they represent a more suitable
system when compared with mouse embryonic stem cells. I validated neural differentiation
of EpiSCs as an alternative model to study neural development in vitro. I found that inhibition
of the FGF/ERK activity at the onset of EpiSC differentiation initiated expression of Wnt and
Shh and further induced ventral midbrain progenitor markers, accompanied by suppressing
caudalisation as well as forebrain induction. To maintain ventral midbrain progenitor fate,
cells required a period of endogeneous FGF/ERK signalling. Subsequent treatment of FGF8
and SHH, which restricts progenitors from adopting alternative fates, led to highly efficient
production of authentic mDA neurons. These neurons exhibited functional, neuron-like
properties and when implanted into the striatum of mouse PD model strongly restored
parkinsonian features without any signs of overgrowth.
In conclusion, a temporally controlled modulation of FGF/ERK activity during neural
differentiation from PSCs is crucial for reliable and highly efficient generation of functional
authentic mDA neurons.
diseases such as Parkinson’s disease (PD), for which there are no effective treatments.
Pluripotent stem cells (PSCs) offer a remarkable potential for finding new therapeutic
strategies because they are self-renewable and capable to differentiate into all cell types.
However, biomedical applications of PSCs require knowledge of the molecular mechanisms
directing PSCs into midbrain dopaminergic (mDA) cell fate.
During development the generation of mDA neurons is induced by the extrinsic molecules
SHH, FGF8 and WNT1 in the caudal region of the Otx2 positive domain, which marks the
presumptive fore- and midbrain, and rostrally to the future hindbrain expressing Gbx2.
In this study I have further investigated the role of FGF signalling in the generation of mDA
neurons. Here, I have used mouse epiblast stem cells (EpiSCs). Based on their
developmentally primed pluripotent state, we assumed that they represent a more suitable
system when compared with mouse embryonic stem cells. I validated neural differentiation
of EpiSCs as an alternative model to study neural development in vitro. I found that inhibition
of the FGF/ERK activity at the onset of EpiSC differentiation initiated expression of Wnt and
Shh and further induced ventral midbrain progenitor markers, accompanied by suppressing
caudalisation as well as forebrain induction. To maintain ventral midbrain progenitor fate,
cells required a period of endogeneous FGF/ERK signalling. Subsequent treatment of FGF8
and SHH, which restricts progenitors from adopting alternative fates, led to highly efficient
production of authentic mDA neurons. These neurons exhibited functional, neuron-like
properties and when implanted into the striatum of mouse PD model strongly restored
parkinsonian features without any signs of overgrowth.
In conclusion, a temporally controlled modulation of FGF/ERK activity during neural
differentiation from PSCs is crucial for reliable and highly efficient generation of functional
authentic mDA neurons.
Date Issued
2012
Date Awarded
2013-03
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Li, Meng
Publisher Department
Institute of Clinical Science
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)