Investigation of mesenchymal stem cell response to bioactive nanotopography

Q Science (General);QH301 Biology

Lee, Louisa Chi Yin ; Dalby, Matthew

University:University of Glasgow

Department:Institute of Molecular Cell and Systems Biology

关键词: Mesenchymal stem cells, nanotopography, biomaterials, seeding density, cell cycle, metabolomics, reprogramming.;   

Others  :  http://theses.gla.ac.uk/7180/1/2016LeePhD.pdf

来源: University of Glasgow

【 摘 要 】

Mesenchymal stem cells (MSC) are multipotent stem cells that have muchpotential 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 nanopatternedsubstrates, known as nanotopography. Use of established nanopit features, inarrangements 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 useof our nanotopographies. Once the fundamental details pertaining to optimalconditions for use of the substrates and cells were established, exploration ofchanges 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.