The circumstances under which one or the other of these different mechanisms takes place is still controversial, and in an attempt to understand the closure of naturally occurring gaps, the research groups of Benoit Ladoux at the Mechanobiology Institute in Singapore (MBI) and Xavier Trepat at IBEC have developed a unique strategy to induce well-defined gaps within epithelial cells and monitor the dynamics of gap closure in the absence of cell injury. At the same time, labs at the MBI, IBEC and the University Paris Diderot have developed a test system involving the use of a stencil to mask the surface available for cells. The removal of the stencil resulted in an array of gaps that were rapidly filled in by the cells moving in from all directions.
“Interestingly, our observations showed that the cells around the edge of the gap protrude arm-like extensions (lamellipodia) into it and gradually fill it,” explains Ester Anon, the first author of the paper published this week in PNAS. “These cells take on the role of leader and crawl their way into the gap.”
This study is significant in understanding the basic mechanics of gap closure in tissues, and the elegant system developed will enable further work towards unraveling the mechanics of gap closure. Such insights will be crucial for a better understanding of developmental and pathophysiological processes.
Añón, E., Serra, X., Hersen, P., Gaulthier, N., Sheetz, M., Trepat, X. & Ladoux, B. (2012). Cell crawling mediates collective cell migration to close undamaged epithelial gaps. PNAS, in press.