FGF signaling in specification of hESC-derived definitive endoderm

Research output: ThesisDoctoral Thesis (compilation)

Abstract

Diabetes affects around 200 million people worldwide. Curing diabetes would
require the prevention of autoimmune destruction of beta cells and restoration of
the beta cell mass restored either through regeneration or transplantation of the
insulin producing cells. Islet transplantation according to the Edmonton protocol
have been the most promising therapeutic option for Diabetes type I patients,
however, lack of cadaveric donor islets is a major obstacle and new strategies need
to be established. Human embryonic stem cells (hESCs) not only offer an excellent
source for establishment of strategies for future regenerative cell therapies and drug
discovery but also offers en excellent experimental assay for understanding human
pancreas development.
Pancreas originates from the definitive endoderm (DE), one of the three germ
layers. The path from definitive endoderm to pancreatic progenitor cells and finally
the insulin producing beta cells involves sequential cell-fate decisions characterized
by the expression of multiple transcription factors. Governed by the developmental
biological principles that normally control foregut endoderm and pancreas
specification, numerous multifactor protocols for directing mature foregut-derived
cells from hESCs have been reported. However, to establish less complex and more
robust protocols there is a need to further understand the mechanism of action of
individual growth and differentiation factors in specification of human pluripotent
stem cells towards foregut derived cell lineages.
Here, we describe two studies where we have investigated the role of fibroblast
growth factor (FGF) signaling, specifically FGF2 and FGF4, and Retinoic acid (RA)
in specification of the hESC-derived DE development. Studies in lower vertebrates
have demonstrated that FGF2 acts in a restricted manner primarily patterning the
ventral foregut endoderm into liver and lung, whereas FGF4 exhibits broad anteriorposterior
and left-right patterning activities. Furthermore, whereas FGF2 is not
required for ventral pancreas development an inductive role of FGF2 has been
shown during dorsal pancreas formation. Whether FGF2 and FGF4 play a similar
role during human endoderm development remained however unknown. In contrast,
RA has frequently been employed (together with other growth factors) for directed
differentiation of hESCs to pancreatic endoderm.
In the first study we show that FGF2 in a dosage-dependent manner specifies
hESC-derived DE into different foregut lineages such as liver, lung, pancreatic
and intestinal cells. Furthermore, by dissecting the FGF receptor intracellular
pathway that regulates pancreas specification, we demonstrate for the first time to
our knowledge that induction of PDX1+ pancreatic progenitors in part relies on
8
FGF2-mediated activation of the MAPK signaling pathway. In the second study, we
show that FGF4 alone is not sufficient for induction of foregut endoderm but that
in combination with RA it efficiently induces PDX1+ cells from hESC-derived DE.
Specifically, FGF4 promoted cell survival in the differentiating hESCs. Hence, in
contrast to studies in lower vertebrates we demonstrate that FGF4 neither patterns
hESC-derived DE, nor induces PDX1+ pancreatic progenitors suggesting that FGF4
is not responsible for anterior-posterior patterning of the primitive gut during human
development.. Altogether, these observations suggest a broader gut endodermal
patterning activity of FGF2 that corresponds to what has previously been advocated
for FGF4, implying a functional switch from FGF4 to FGF2 during evolution. Thus,
our results provide new knowledge of how cell fate specification of human DE is
controlled – facts that will be of great value for future regenerative cell therapies.
Finally, we present a method for efficient gene targeting in hESCs, which allows the
monitoring of gene expression in living cells.

Details

Authors
  • Jacqueline Ameri
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Cell and Molecular Biology
Original languageEnglish
QualificationDoctor
Awarding Institution
Supervisors/Assistant supervisor
  • Henrik Semb, Supervisor
Award date2010 Jan 29
Publisher
  • Stem Cells and Pancreas Development Biology
Print ISBNs978-91-86443-20-7
Publication statusPublished - 2010
Publication categoryResearch

Bibliographic note

Defence details Date: 2010-01-29 Time: 13:00 Place: Segerfalksalen, BMC External reviewer(s) Name: Grapin-Botton, Anne Title: PhD Affiliation: Swiss Institute for Experimental Cancer Research (ISREC), École Polytechnique Fédérale de Lausanne (EPFL) --- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Stem Cell and Pancreas Developmental Biology (013212044)

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Related research output

Ameri, J., Ståhlberg, A., Pedersen, J., Johansson, J., Johannesson, M., Isabella Artner & Semb, H., 2010, In : Stem Cells. 28, p. 45-56

Research output: Contribution to journalArticle

Johannesson, M., Ståhlberg, A., Ameri, J., Wolfhagen Sand, F., Norrman, K. & Semb, H., 2009, In : PLoS ONE. 4, 3, e4794.

Research output: Contribution to journalArticle

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