High-content image informatics of the structural nuclear protein NuMA parses trajectories for stem/progenitor cell lineages and oncogenic transformation

Abstract

Stem and progenitor cells that exhibit significant regenerative potential and critical roles in cancer initiation and progression remain difficult to characterize. Cell fates are determined by reciprocal signaling between the cell microenvironment and the nucleus; hence parameters derived from nuclear remodeling are ideal candidates for stem/progenitor cell characterization. Here we applied high-content, single cell analysis of nuclear shape and organization to examine stem and progenitor cells destined to distinct differentiation endpoints, yet undistinguishable by conventional methods. Nuclear descriptors defined through image informatics classified mesenchymal stem cells poised to either adipogenic or osteogenic differentiation, and oligodendrocyte precursors isolated from different regions of the brain and destined to distinct astrocyte subtypes. Nuclear descriptors also revealed early changes in stem cells after chemical oncogenesis, allowing the identification of a class of cancer-mitigating biomaterials. To capture the metrology of nuclear changes, we developed a simple and quantitative “imaging-derived” parsing index, which reflects the dynamic evolution of the high-dimensional space of nuclear organizational features. A comparative analysis of parsing outcomes via either nuclear shape or textural metrics of the nuclear structural protein NuMA indicates the nuclear shape alone is a weak phenotypic predictor. In contrast, variations in the NuMA organization parsed emergent cell phenotypes and discerned emergent stages of stem cell transformation, supporting a prognosticating role for this protein in the outcomes of nuclear functions.

Orthogonal potency analysis of mesenchymal stromal cell function during ex vivo expansion

“…We found that cell area increased progressively with age while nuclei size and shape became smaller and less elongated. Alterations in nuclear biology during MSC aging continue to be dissected as a way to characterize cell state [62, 63]. In keeping with the trends mentioned above, we found strong correlations between age and adipogenic potential, consistent with both our previous findings as well as that of the field.…”

Fluorescence Imaging of Actin Turnover Parses Early Stem Cell Lineage Divergence and Senescence

“…Our previous gene expression analysis shows several clusters of genes upregulated early during lineage divergence, including cell cycle genes and nuclear splicing factor genes, especially Nuclear mitotic apparatus protein, NuMA 46 . Morphotextural descriptors of NuMa were able to distinguish phenotypes with greater efficacy when combined with descriptors for actin filaments in MSCs 47 .…”

The mitotic protein NuMA plays a spindle-independent role in nuclear formation and mechanics

“…1 , 2 , and 5 ) and regulatory functions in the nucleus. Uncovering NuMA’s nuclear functions may in turn help understand why its localization varies depending on cell phenotype ( Knowles et al, 2006 ; Vega et al, 2017 ). Similarly, it will shed light on why NuMA’s expression level and impact on nuclear architecture vary dramatically between epithelial cells and highly specialized or terminally differentiated cells ( Merdes and Cleveland, 1998 ).…”