Predicting the individual and collective behaviour of stem cell communities

Individual cell behaviour will be influenced by neighbouring cells and the collective function of the cellular societies in which they exist. The growth of a colony from a single cell is an interesting biological event in which to analyse individual and group behaviour. This is particularly relevant for adult mesenchymal stem cells (MSCs) that form single cell-derived colonies with clear inter-colony heterogeneity. Cell division will also generate non-identical daughter cells, delivering different degrees of asymmetric partitioning even from genetically-identical clones, so subtle intra-colony heterogeneity will also exit. Previously, we have used different immortalised clonal MSC lines to characterise single cell and collective behaviour during colony formation using real-time ptychographic microscopy. This permits label-free high contrast imaging, followed by quantitative image analysis to characterise cellular morphologies as well as dynamic and temporal features. We have identified significant inter-clone differences in multiple morphometric parameters (e.g. cell morphology, size, sphericity, migratory distance, speed, track length, meandering index, collective cell behaviour), which can be indirectly linked to ability of the MSC lines to differentiate into different cell types. This work therefore provides a platform on which we can build an understanding of the basic biological mechanisms underlying the organisation of cell communities and, as a consequence, tissue development. This work will be expanded as part of the proposed project to provide a comprehensive morphometric dataset based on the existing clonal lines to help build machine learning algorithms. From these analyses, we will be able to determine the origin, extent and propagation of cellular heterogeneity, which can then be related to differentiation capacity of the clonal MSC lines. Mechanistic studies will include CRISPR/Cas9-targeting of candidate regulators (e.g. FGF, Wnt signalling). We will use this information to predict the behaviour of MSC colonies isolated from heterogeneous primary bone marrow-derived MSC populations.