Role for DLK1 in neuronal differentiation of mouse and human embryonic stem cells

One of the fundamental goals in neuroscience is to understand how the diverse types of neurons are generated by stem and progenitor cells in the vertebrate central nervous system. To understand the mechanism that underlies this process, a greater knowledge of the molecular control of the acquisition of neuronal identity is still required. This knowledge is not only important for understanding of normal central nervous system development, but is also key to uncovering the mechanisms of neurological diseases. In the last decades a great progress in the in vivo studies has been made, thus enabling for generation of neural progenitor cells (NPCs) from pluripotent embryonic stem cells (ESCs) in vitro. There are a few signalling molecules and growth factors known to be involved in the progression of NPCs to neurons in vitro and in vivo, which act as components of signalling pathways such as Notch, Shh and Wnt. Role of Notch pathway is however the best characterised. In this thesis a role for protein that belongs to the family of Notch receptors and ligands, called Delta like 1-homologue (DLK1), in neuronal differentiation of ESCs-derived NPCs was investigated. Firstly time course of DLK1 expression during in vitro neuronal differentiation of mouse ESCs and in the developing mouse brain was examined. The results indicated that the expression of DLK1 is associated with neuronal differentiation. Following that the effect of DLK1 on the differentiation and proliferation of hESCs and mESCs-derived NPCs was tested. Induction of DLK1 in mNPCs, by making use of CreERT2 system, as well exposure of hNPCs to the molecule resulted in positive modulation of the number of differentiated neurons. Moreover DLK1 did not seem to have any effect on cell proliferation. Lastly to addresses a question whether DLK1 acts through Notch pathway, Hes1 luciferase assay was applied. The data showed that DLK1 negatively regulates Hes1 luciferase activity in mNPCs and hNPCs. Downregulation of Hes1 transcript was further confirmed by qPCR. Taken together studies described in this thesis propose a novel function for DLK1 as one of the molecules involved in the complex cascade of factors modulating neuronal differentiation.EThOS - Electronic Theses Online ServiceSPRING/Parkinson?s Disease SocietyGBUnited Kingdo