In the same way that people are demanding when choosing the mattress they want to sleep on – not too hard, but not too soft – so are cells. In fact,the rigidity of the cellular environment is so important that it can determine whether a stem cell will differentiate into bone or fat, for example. Even if a cell will behave normally or become cancerous.
In an article published in the latest issue of the magazinePNAS, researchers from the Institut de Bioenginyeria de Catalunya (IBEC) in Barcelona announce the discovery of a crucial mechanism by which cells explore their environment, which has brought them one step closer to understanding how they interact with their surroundings. This result opens doors to powerpredict or even control cellular behavior.
“How a cell can measure the stiffness of its environment has been a mystery for a long time,” explains Pere Roca-Cusachs, senior researcher in the Cell and Respiratory Biomechanics group at IBEC, who carried out the research with collaborators from the USA. “Do you exert a certain force on your environment, and then measure how much it moves, like a person jumps on a bed to see how it gives way? Or do you apply a certain distortion, and then measure how much force it requires? does the cell perform as a whole, or does it have multiple miniature sensors that check stiffness at different points? “
To answer these questions, scientistsplaced cells on a bed of flexible nanometric pillars. “By following the movement of these pillars, we were able to map how cells exert forces in their environment with a resolution never before obtained,” explains Pere. “Using this technique, we discovered that the cell stiffness sensor is a small complex no more than one micrometer (1/1000 of a millimeter) long.” The researchers also found that the cell has multiple copies of this complex, and that they all apply a constant 60 nanometer displacement – less than 1 / 10,000 of a millimeter. The sensors then measure the applied force to deduce the stiffness of the medium.
“These findings represent a very important step towards understanding how cells interact with their environment, crucial knowledge formake organs like lungs or hearts in vitro or treat diseases like cancer, “says Pere.
