Depletion of CAPSL in HRECs compromises in vitro EC proliferation and migration.
(A) Representative images of in vitro tube formation after transfection of HRECs with shRNA. Scale bar: 200 μm. Error bars indicate the SD. ***P < 0.001, ****P < 0.0001, by Student’s t test (n=6). (B) Incorporation of EdU in shRNA transfected HRECs. Representative confocal images and quantification of proliferating HRECs both in number per field and proportion of EdU-positive cells. Scale bar: 50 μm. Error bars indicate the SD. ****P < 0.0001, by Student’s t test (n=10). (C-D) Cell cycle analysis of shCtrl-ECs and shCAPSL-ECs by flow cytometry. Error bars indicate the SD. ****P < 0.0001, by Student’s t test (n=4). (E) Representative images of phalloidin actin cytoskeleton (green) and GM130 (red) showing polarity angles of shCtrl-ECs and shCAPSL-ECs at the edge of scratch wound. The arrow points toward the wound. Colored arrowheads represent different migration state. Scale bar: 200 μm (left panel) 50 μm (right panel). (F) Quantification of nuclear ellipticity of HRECs at the margin of wound scratch. Error bars indicate the SD. ****P < 0.0001, by Student’s t test (n = 14). (G) Schematic pictures showing the define of polarity axis of each cell. Polarity axis was measured with the angle (α) between the scratch edge and the vector drawn from the center of nucleus to the center of the Golgi apparatus. (H) Polar plots showing Golgi apparatus polarization. The bold lines represent 120° region centered on the vector, which is perpendicular to the wound scratch. The dots represent the angle (α) of each cell and the numbers indicate the frequency of dots within the 120° region of the bold line of shCtrl-ECs (n=243) and shCAPSL-ECs (n=244). (I) Images of phalloidin-stained actin cytoskeleton and comparisons of indicated parameters in shCtrl-ECs and shCAPSL-ECs at the edge of scratch wound. The dashed boxed region is shown at higher magnification at the bottom panel. Scale bar: 50 μm (top panels), 25 μm (bottom panels). (J) Representative images of wound scratch assay at 0h, 12h, and 16h after wound was made. And the quantification of covered area at different time point. The dashed line indicates the gap of the wound after wound scratch at different time point. Scale bar: 200 μm. Error bars indicate the SD. ****P < 0.0001, ns: no significance, by Student’s t test (n = 4). (K) Immunoblot and quantification analysis of expression of small GTPase proteins and a key regulator of contractile force MYL9 in shCtrl-ECs and shCAPSL-ECs. Error bars indicate the SD. *P < 0.05, **P < 0.01, ***P < 0.001, by Student’s t test (n = 3).