Cells detect stiffness and grow accordingly.

[Mr Skeptic]

According to this New Scientist article, cells can detect the stiffness of surrounding tissue, and use that as a cue as to what cell is should become. Apparently, when grown on a gel of a given stiffness, they choose to become a tissue of similar stiffness. They can also detect stuff like fluid flow, which prompts them to become blood vessels. This makes sense as this is a much more flexible approach than a genetically pre-programmed objective (I don't know how well it compares to chemical signaling however, although this way they don't need to be ordered around).

 

This has significance for healing, since scar tissue is stiffer than normal tissue. Scars inhibit nerve regeneration (nerves prefer soft tissue), for example. It may also have significance for cancer: cancer is much harder than normal tissue. It also has significance for evolution, as a more independent cell can better deal with evolutionary changes. Also, it helps explain certain adaptive features such as things getting stronger with exercise.

 

I'm rather surprised this is the first I've heard of this.

[CharonY]

There are papers out there in which cell signaling are affected by stiffness, geometry etc. of the surrounding tissues. These are of course prerequisites for cell differentiation. I do not think that they used stem cells (and hence also looked at differentiation). I have not read the article but if the second paragraph is pulled from it, it is IMO overselling the points by quite a bit.

[Mr Skeptic]

All the above is my own summary of the article, though New Scientist does maintain a reputation of overselling its points. Still, it does seem rather important.