Figure 10.

Erk5 knockdown in HaCaT cells hampers postwound reepithelialization and reduces cell–cell adherence. SH-Control and SH-Erk5 HaCaT cells were grown to confluency then wounded as described in Material and Methods. Wound area was measured by phase microscopy immediately after the wound (T0) and after 24-h reepithelialization (T24) (A) Low-magnification picture shows a delay in reepithelialization pattern in SH-Erk5 cells. (B) High-magnification picture shows a poor cohesiveness between front migrating SH-Erk5 cells, when SH-Control migrate as a more cohesive sheet (arrows). High-magnification picture from SH-Erk5 cells was taken after about 15-h reepithelialization, when the wound was not fully covered, as seen on A. (C) Relative reepithelialization was computed as T0T24, related to SH-Control. Each value is the average of five distinct wells for each condition. Error bars, SD (population). Statistical analysis using Student's test; *significant difference (p = 0.03) between SH-control and SH-Erk5 cells. (D) Cell–cell adherence was estimated by growing isolated cells in suspension for 120 min on a rotary shaker, to favor aggregation, according to a published method. Cell aggregates were counted and sorted into four size classes, based on the number of cells included. Percentage of cells involved in each class was calculated and reported in D. Examples of larger aggregates are shown in E.