Investigation of mesenchymal stem cell response to bioactive nanotopography

Lee, Louisa Chi Yin (2016) Investigation of mesenchymal stem cell response to bioactive nanotopography. PhD thesis, University of Glasgow.

Abstract

Mesenchymal stem cells (MSC) are multipotent stem cells that have much
potential for application in regenerative medicine, with their ability to self-renew and to undergo differentiation into several lineages, including those that comprise fat, bone, and cartilage. Studies on MSCs have mainly focused on exploiting their capacity to differentiate, rather than self-renewal, yet understanding of the latter process is pivotal for the expansion of these cells to sufficient numbers for use in future clinical treatments.
Aspects of MSC behaviour can be induced by culture on nanopatterned
substrates, known as nanotopography. Use of established nanopit features, in
arrangements known to maintain MSC multipotency over long periods in culture (SQ), in addition to an osteogenic promoting arrangement (NSQ), were used as a tool to study self-renewal in MSCs, and begin to elucidate some of the potential mechanisms underlying the effects of the nanotopographies on stem cell fate.
This study utilised patient-specific primary MSCs derived from bone marrow,
which were optimised in terms of initial seeding density, to make efficient use
of our nanotopographies. Once the fundamental details pertaining to optimal
conditions for use of the substrates and cells were established, exploration of
changes in metabolism, cell cycle and gene expression were carried out. Results indicated that MSCs on SQ contained more unsaturated metabolites, and that cell cycle may be altered, which warranted further investigation. Further study identified some differences in cell cycle regulatory proteins when compared to NSQ and flat controls. Further inferences were achieved by analysis of transcript abundances and differential expression, supporting the hypothesis of a heterogeneous population existing on NSQ, and activation of pathways linked to differentiation, consistent with previous work. A greater percentage of MSCs on SQ were shown to be in the early G0/G1 stages of the cell cycle in comparison to those on flat, suggesting that cell cycle is altered and further establishes a link between self-renewal and cell cycle regulation.
Nanotopography was assessed for a novel application, namely the potential of SQ to reprogram differentiating MSCs. Nanotopography was used to induce and reverse the onset of osteogenic differentiation, and evaluated in conjunction with the addition of an epigenetic modifier, valproic acid. Results did not indicate that nanotopographical cues were able to reprogram MSCs. However, promising indications that stem cell marker STRO-1 levels increased, is consistent with SQ being a surface that maintains ‘stemness’ and multipotency of MSCs with culture in vitro.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Mesenchymal stem cells, nanotopography, biomaterials, seeding density, cell cycle, metabolomics, reprogramming.
• Subjects: Q Science > Q Science (General); Q Science > QH Natural history > QH301 Biology
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Supervisor's Name: Dalby, Professor Matthew, Gadegaard, Professor Nikolaj, Yarwood, Dr. Stephen and Meek, Mr. RM Dominic
• Date of Award: 2016
• Depositing User: Miss Louisa Chi Yin Lee
• Unique ID: glathesis:2016-7180
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 26 Apr 2016 07:21
• Last Modified: 26 Apr 2016 07:52
• URI: https://theses.gla.ac.uk/id/eprint/7180