Three-dimensional geometry controls division symmetry in stem cell colonies

Abstract

Proper control of division orientation and symmetry, largely determined by spindle positioning, is essential to development and homeostasis. Spindle positioning has been extensively studied in cells dividing in 2-dimensional (2D) environments and in epithelial tissues, where proteins such as NuMA orient division along the cell's interphase long axis. However, little is known about how cells control spindle positioning in 3-dimensional (3D) environments, such as early mammalian embryos and a variety of adult tissues. Here, we use mouse embryonic stem (ES) cells, which grow in 3D colonies, as a model to investigate division in 3D. We observe that at the periphery of 3D colonies, ES cells display high spindle mobility and divide asymmetrically. Our data suggest that enhanced spindle movements are due to unequal distribution of the cell-cell junction protein E-Cadherin between future daughter cells. Interestingly, when cells progress towards differentiation, division becomes more symmetric, with more elongated shapes in metaphase and enhanced cortical NuMA recruitment in anaphase. Altogether, this study suggests that in 3D contexts, the geometry of the cell and its contacts with neighbors control division orientation and symmetry.

Crosstalk between the plasma membrane and cell-cell adhesion maintains epithelial identity for correct polarised cell divisions

“…Next, we performed live imaging in polarised and non-polarised MCF-10A cells, in which we labelled the plasma membrane with CellMask TM and DNA with Hoechst 33342. Consistent with previous studies 42 , CellMask TM displays a homogeneous, circumferential distribution at the cell surface of polarised mitotic cells, which generate equal-sized daughter cells at cytokinesis (Figures 1C-1E; Movie S1). In non-polarised mitotic cells, however, the plasma membrane has aberrant dynamics with ~52% of cells displaying a unilateral accumulation of CellMask TM at the cell surface (Figures 1C-1E; Movie S2; Movie S3).…”

Diversity is the spice of life: An overview of how cytokinesis regulation varies with cell type

“…Cytokinesis is influenced by intrinsic and extrinsic factors that affect filament alignment for constriction and include polarity, cell–substrate adhesion and adherens junctions ( Higashi et al, 2016 ; Pinheiro et al, 2017 ; Dix et al, 2018 ; Chaigne et al, 2021 ; Gupta et al, 2021 ; Ozugergin et al, 2022 ; Paim and FitzHarris, 2022 ). Along with causing different rates of ingression, these factors can also cause ingression to be more asymmetric ( Figure 1C ).…”

Endogenous tagging using split mNeonGreen in human iPSCs for live imaging studies

“…Despite this incredible resource, few studies have investigated cellular processes in human stem cells and differentiated cell types with high spatiotemporal resolution ( Dambournet et al, 2018 ; Viana et al, 2023 ). For example, several studies describe the regulation of mitosis and cytokinesis in mouse embryos and embryonic stem cells ( Chaigne et al, 2020 ; Chaigne et al, 2021 ; Paim and FitzHarris, 2022 ), but not in human stem cells. Since most of our knowledge of human cell cytokinesis is derived from diseased and/or transformed cell lines, the field will benefit greatly from studying iPSCs before and after differentiation in an isogenic context, particularly since they represent ‘healthy’ human cells ( Dambournet et al, 2018 ; Drubin and Hyman, 2017 ).…”