Fig. 2. Relationship between proliferation and amount of cell-cell contact.

(A–D) Differential interference contrast micrographs and illustrations (insets) of groups of one (A), two (B), three (C), or four (D) BPAECs. These wells are referred to in the text by the shapes they resemble: a triangle (A), a bowtie (B), a boomerang (C), and a propeller (D). The cells are patterned using dielectrophoresis and constrained with agarose wells such that, within the groups, cells contact zero to three neighbors. (E) Phase contrast image of groups of four cells, overlaid with corresponding nuclear stain (blue) used to verify correct cell number for all experiments. (F) Graph of BrdU incorporation with one- and three-cell groups (having zero, one, or two neighbors). (G) Graph of BrdU incorporation with one- and four-cell groups (having zero, one, or three neighbors). (H) Combined graph of BrdU incorporation in cells with zero to three neighbors. To correct for drift in baseline proliferation between experiments, the data in (H) are normalized to the value for cells with no neighbors. In (F–H), shaded cells in illustrations correspond to cell(s) analyzed for the corresponding data point. Error bars are standard error, with (*) p<0.05 versus zero neighbors, (**) p<0.001 versus zero neighbors, and (#) p<0.05 versus one neighbor by paired t-test. Scale bars are 10 µm.