Materials-based strategies for epigenetic control of stem cell fate
File(s)
Author(s)
Morez, Constant
Type
Thesis
Abstract
Direct reprogramming strategies for cell fate switching hold great promise for regenerative
medicine. However, because of the strong stability provided by a cell's
epigenome, the efficiency associated with such processes remains critically low. This
study shows that the use of microgrooved substrates can dramatically alter a cell's
epigenetic landscape. More specifically a significant disruption of the repressive heterochromatin
is observed, characterised by a significant diminution of H3K27me3
and H3K9me3 levels and an increase in H3K4me3. In the specific case of cardiac
direct programming through viral over-expression of key transcription factors, the
use of these parallel microgrooves can significantly increase the number of induced
cardiomyocyte-like cells generated. In addition microgrooved substrates can also
stimulate histone acetylation, thereby increasing chromatin accessibility, and concomitantly
stimulate sumoylation of the co-activator myocardin, thereby enhancing
its cardiogenic capacity. Moreover, the alignment provided by the substrate can foster
the establishment of organized sarcomeric structures, and therefore strengthen
the maturation of the induced-cardiomyocytes. Lastly, the potential effect of the
microgrooved substrate in neural progenitor differentiation is investigated. Interestingly,
a strong epigenetic remodelling is also observed. However, apart from a
notable induced histone hyper-acetylation, its characteristics are strikingly different,
with notably a strong stimulation of the repressive H3K9me3 mark. Remarkably,
neural progenitor differentiation triggered by the addition of soluble factors yielded
significantly more neurons on the microgrooved substrates.
medicine. However, because of the strong stability provided by a cell's
epigenome, the efficiency associated with such processes remains critically low. This
study shows that the use of microgrooved substrates can dramatically alter a cell's
epigenetic landscape. More specifically a significant disruption of the repressive heterochromatin
is observed, characterised by a significant diminution of H3K27me3
and H3K9me3 levels and an increase in H3K4me3. In the specific case of cardiac
direct programming through viral over-expression of key transcription factors, the
use of these parallel microgrooves can significantly increase the number of induced
cardiomyocyte-like cells generated. In addition microgrooved substrates can also
stimulate histone acetylation, thereby increasing chromatin accessibility, and concomitantly
stimulate sumoylation of the co-activator myocardin, thereby enhancing
its cardiogenic capacity. Moreover, the alignment provided by the substrate can foster
the establishment of organized sarcomeric structures, and therefore strengthen
the maturation of the induced-cardiomyocytes. Lastly, the potential effect of the
microgrooved substrate in neural progenitor differentiation is investigated. Interestingly,
a strong epigenetic remodelling is also observed. However, apart from a
notable induced histone hyper-acetylation, its characteristics are strikingly different,
with notably a strong stimulation of the repressive H3K9me3 mark. Remarkably,
neural progenitor differentiation triggered by the addition of soluble factors yielded
significantly more neurons on the microgrooved substrates.
Version
Open Access
Date Issued
2015-09
Date Awarded
2016-03
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
STEVENS, Molly M
SCHNEIDER, Michael D
Sponsor
British Heart Foundation
Publisher Department
Materials
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)