Figure 1

Monocyte migration correlates with contraction at the cell rear. (A) Fraction of cells displaying blebs in suspension culture or when confined down to 3 µm by a PDMS ceiling, as measured by live imaging of THP-1 monocyte-like cells stained with a membrane dye. Statistical significance was determined by a t-test (mean ± SEM). A representative image of cells confined down to 3 µm by a PDMS ceiling stained with membrane dye is shown in (A’). For 2D confinement, PDMS is coated with bovine serum albumin (BSA; 1%). (B) Montage of a THP-1 monocyte-like cell with the F-actin marker, LifeAct-EGFP, migrating within a confining channel. (C) Zoom from (B; top) showing multiple small blebs at the leading edge. (D) Zoom from (B; bottom) showing contraction of the cell rear, as indicated by increased curvature. (E) Localization of myosin in a motile cell, as indicated by RLC-EGFP. (F) Zoom from (E; top) showing a low level of RLC-EGFP at the leading edge. (G) Zoom from (E; bottom) showing a high level of RLC-EGFP at the trailing edge. (H) Ratio of RLC-EGFP at the leading edge over the trailing edge in poorly motile (i.e., moving less than half of the cell body length over 5 h) and motile cells. Statistical significance was determined by a t-test (mean  ± SEM). Microchannels are coated with VCAM-1 (1 µg/mL) and are 3 µm in height, 8 µm in width, and 100 µm in length. *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, and ****p ≤ 0.0001.