L-proline-mediated mechanisms driving neural differentiation from mouse embryonic stem cells

Abstract

Cells within the mammalian embryo must transition through primitive ectoderm, definitive ectoderm and neurectoderm before developing into neural cells to produce the nervous system. These transitions rely heavily on highly complex mechanisms that must be tightly controlled. Early neural development remains one of the most poorly understood areas of developmental biology due to the complex nature of the molecular mechanisms and inaccessibility of the mammalian environment. Amino acids and metabolic processes are now recognised as part of the complex system of mechanisms required to drive cell fate. In pluripotent mouse embryonic stem cells as a developmental model, L-Proline acts as a growth factor driving neural differentiation by activating signalling pathways such as mTOR and MAPK/ERK. In addition, its metabolism plays a role. This thesis investigates various mechanisms driving differentiation to cells of the nervous system, with particular emphasis on L-Proline, its metabolism, and the effect it has on transcription of various genes and transcriptional circuits. While a large number of studies look at neural-cell production from neurectoderm onwards, few have focused, as we do here, on events prior to this: the formation of definitive ectoderm and neurectoderm formation. This thesis will also look at the expression of genes and proteins associated with motor neurone disease. According to the Developmental Origin of Health and Disease Hypothesis, compromised expression of such genes and proteins during early development in utero may combine with environmental factors which result in the onset of this neurodegenerative disease later in life.