Fig. 1: Morphological and mechanical remodeling of the nucleus in macrophages upon LPS stimulation.

a The average size of the THP-1-derived macrophage or PEM nuclei after LPS challenge. THP-1-derived macrophages and PEMs were treated with 100 ng/ml LPS for indicated time periods. The cells were then washed with PBS and placed in normal culture condition. After live staining with Hoechst 33,342, the nuclei were observed every 90 s for 1 h using Opera High Content Screening Platform. For each time point, 5000 nuclei were measured to obtain the indicated average size. The x-axis represents hours after the LPS challenge. Fluorescence microscopy of Phalloidin and DAP in THP-1-derived macrophages (b, 40 cells per group) or PEMs (c, n = 48 cells per group) after LPS stimulation. The nuclear volume was quantified. In the box plots, the center line corresponds to the median and box corresponds to the interquartile range (IQR). Each dot represents one cell. Scale bar, 5 μm. d Nuclear envelope spacing determined by scanning electron microscopy. The nuclear envelope spacing was highlighted by red arrows and quantified as NE distance (n = 35 cells per group). Main image scale bar, 1 μm. Inset image scale bar, 0.2 μm. e Atomic force microscopy images of nuclei separated from LPS-treated macrophages and from controls (n = 20 cells per group). f A schematic model showing how the nucleus changes in size and shape during macrophage polarization. Two-sided Tukey post-hoc test was used to compared differences between groups after One-way ANOVA (a). Data were presented as mean ± SD (d,e). Two-sided unpaired student’s t test were used (b–e). **p < 0.01; ***p < 0.001 in comparison with control group. See also Supplementary Fig. 1.