Figure 3.

Stretch Induces Changes in NE Tension and Nuclear Mechanical Properties

(A) Representative Lamin A/C images and quantification of EPCs exposed to stretch. Increased nuclear wrinkling (red arrows) is observed in 5% and transiently in 40% stretch. White arrows indicate stretch direction (three independent experiments with n > 350 cells/condition/experiment; ^∗p = 0.0451, ANOVA/Dunn’s).

(B) Representative STORM images of Lamin A/C immunofluorescence (n > 34 cells/condition visualized from three independent experiments).

(C) Representative structured illumination microscopy (SIM) images and intensity line scans from Lamin A/C and H3K9me3 immunostainings (inset: H3K9me3 alone). Dotted lines mark outer edges of Lamin A/C staining and arrowheads the most peripheral peak of H3K9me (n > 41 cells/condition from three independent experiments).

(D) Representative electron micrographs and quantification of nuclear lamina-associated heterochromatin indicate transient nuclear wrinkling and decreased lamina-associated heterochromatin after 30 min of 40% stretch (n > 40 cells pooled across three independent experiments; ^∗p = 0.00284, Kruskal-Wallis/Dunn’s).

(E) Force indentation spectroscopy showing sustained and transient decrease in nuclear elastic modulus in EPC monolayers subjected to 5% and 40% stretch, respectively (n > 140 nuclei/condition pooled across three independent experiments; ^∗∗∗∗p = 0.0013, Kruskal-Wallis/Dunn’s).

(F) Distribution of fluorescence lifetimes with Gaussian fits for Flipper-TR membrane tension probe. Note decreased nuclear membrane tension at 30 min of stretch (n > 360 nuclei/condition from three independent experiments; ^∗∗p < 0.0001, Kolmogorov-Smirnov).

Scale bars represent 2 μm in (D) and 5 μm in other panels. AU, arbitrary units.

See also Figure S3.