Exploring cell-substrate interactions in stem cell self-renewal and differentiation
Author(s)
LaPointe, Vanessa Lydia Simone
Type
Thesis
Abstract
Tissue engineering aims to replace diseased or damaged tissue, one approach for which is to
implant cells and a scaffold developed in vitro. One of the engineering challenges is the design
of the cell-material interface. Cells respond to a wide range of signals from their substrate,
which can be used to control cell behaviour and improve the properties of the implant. Of
particular interest to regenerative medicine is that substrate properties can influence stem cell
self-renewal and differentiation. This thesis aimed to first better understand how substrate
properties such as chemical composition and topography affect stem cell behaviour. For this,
two substrates were studied: one with micrometre scale topography, and one with varying
chemical composition and nanometre scale topography, for their effect on murine embryonic
stem cell (ESC) self-renewal and early differentiation. On micrometre scale topography, the first example of central pit formation due to substrate cues was observed, and the substrates
mitigated endoderm specification. On nanometre scale topography, ESC early differentiation
markers were diminished, and both substrate topography and chemical composition affected cell behaviour. Then attention was shifted to how biological cues from the substrate, such as
ligands specific to cell surface receptors, could guide stem cell chondrogenic differentiation.
In that study, the changing adhesion requirements of human mesenchymal stem cells were
studied in the form of integrin transcript expression and finally, the role of one specific integrin
was shown to affect chondrogenic differentiation in vitro. This was the first complete
characterisation of integrin expression and the first demonstration of the role of integrin αvβ8
in chondrogenic differentiation. Overall, these results improve the understanding of how stem
cells respond to substrate cues, including some of the crucial cues they require in differentiation,
and could therefore be used to improve the design of tissue engineering scaffolds.
implant cells and a scaffold developed in vitro. One of the engineering challenges is the design
of the cell-material interface. Cells respond to a wide range of signals from their substrate,
which can be used to control cell behaviour and improve the properties of the implant. Of
particular interest to regenerative medicine is that substrate properties can influence stem cell
self-renewal and differentiation. This thesis aimed to first better understand how substrate
properties such as chemical composition and topography affect stem cell behaviour. For this,
two substrates were studied: one with micrometre scale topography, and one with varying
chemical composition and nanometre scale topography, for their effect on murine embryonic
stem cell (ESC) self-renewal and early differentiation. On micrometre scale topography, the first example of central pit formation due to substrate cues was observed, and the substrates
mitigated endoderm specification. On nanometre scale topography, ESC early differentiation
markers were diminished, and both substrate topography and chemical composition affected cell behaviour. Then attention was shifted to how biological cues from the substrate, such as
ligands specific to cell surface receptors, could guide stem cell chondrogenic differentiation.
In that study, the changing adhesion requirements of human mesenchymal stem cells were
studied in the form of integrin transcript expression and finally, the role of one specific integrin
was shown to affect chondrogenic differentiation in vitro. This was the first complete
characterisation of integrin expression and the first demonstration of the role of integrin αvβ8
in chondrogenic differentiation. Overall, these results improve the understanding of how stem
cells respond to substrate cues, including some of the crucial cues they require in differentiation,
and could therefore be used to improve the design of tissue engineering scaffolds.
Date Issued
2012-10
Date Awarded
2013-02
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Stevens, Molly
Sponsor
Overseas Research Students Fees Support Scheme ; The Edward and Eva Underwood Charitable Foundation ; Rosetrees Trust
Publisher Department
Materials
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)