HEALING: Tight junctions for a well-closed wound

Tight junctions are belt-like junctions that surround the cell and provide a seal to the tissues, but also condition the ability of cells to move together in harmony for the proper conduct of many biological processes in our body, including wound healing. wounds. This movement is made possible by the connections between individual cells. These connections are made possible by different protein molecules which transfer the necessary forces and data between neighboring cells.

The key role of tight junctions in wound healing

The Göttingen research team with colleagues from the Max Planck Institute demonstrate here that particularly close connections called “tight junctions” play an important role in the cell movement necessary for wound healing, epithelialization and closure. the wound.

  • Losing these junctions breaks collective cell movement

The study: the researchers therefore studied the connections between cells using a whole arsenal of biophysical techniques. Using video microscopy and automated analyzes, they were able to examine the properties of thousands of living cells in motion for more than 20 hours. Their research included observing the size, shape and mobility of cells. Specific proteins have also been stained to find out what happens at the molecular level when the “tight junction” connections are lost.

  • If some of these special connections are lost, neighboring cells can no longer pair as they usually would. Individual cells begin to contract very strongly and a sort of ‘pull’ between cells develops: ‘Some cells gain and contract to tiny sizes, while other cells’ shed ‘and are stretched,’ explains the author. Lead author Professor Andreas Janshoff, University of Göttingen: “Some cells even begin to divide more in the process, creating more and more small winning cells. The contracted cells hardly move, so the whole tissue behaves as if it were frozen.
  • On the other hand, when these tight junctions are functional, the cell layer remains very mobile, similar to water: Thus,
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in healthy tissues, with tight functional junctions, wounds can heal effectively,

and, epithelial cells retain their protective barrier function.

This mechanism which sometimes induces an arm wrestling between the cells critically obstructs cell movement and certain biological functions. This is the case with scarring, but also with cell division. Thus, the understanding of “tight junctions” is not only essential to that of cell movement and wound healing, it could also contribute to the understanding of certain cancers.