The path of stem cell development depends on its shape
Last reviewed: 16.10.2021
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To direct the stem cell along the necessary path of development, it is not necessary to supply it with appropriate hormones and other biochemical signals, it is enough simply to force it to take the shape of the cell of the desired tissue.
What causes stem cells to turn into another, strictly defined type of cells? How, for example, do bone stem cells learn that they need to become a bone cell rather than cartilage? These issues are of great importance for both fundamental science and applied science. In regenerative medicine, diseased tissues are replaced by healthy ones, obtained from stem cells, and physicians should be sure that stem cells will turn into the right tissue.
It is known that such cells obey chemical signals: a hormone can command a stem cell to give rise to one or another mature tissue. On the other hand, there is evidence that cell differentiation depends on the type of surface on which the cell culture lives and multiplies: the contact of the cell with the substrate determines its fate. Researchers from the National Institute of Standards and Technology (USA) suggest that the transformation of the stem cell depends on the shape that it had to take.
For the cultivation of tissue from stem cells, medics use temporary polymeric implants, which serve as a substrate, a three-dimensional foundation. The skeleton-implant organizes cells in space and directs their growth. In the experiment, scientists planted stem cells of bone tissue into several types of such implants, which differed in spatial structure. In this case, the cells were grown without adding any hormones or other substances that could "tell" them about the path of development. As a result, in only one case out of five, stem cells began to accumulate calcium, which is evidence of their transformation into a mature bone cell. To successfully gain a foothold on this substrate, the cells had to stretch and give long processes, that is, take the form of a mature osteocyte.
Thus, as the authors write in the journal Biomaterials, stem cells can be pushed to the desired development path without any chemical signal cocktails. It is enough to give them a characteristic form, inherent in the cells of the desired tissue.
At first glance, the result is strange and incomprehensible. It's like saying: students become doctors because in medical practice they are forced to wear white robes. Scientists have yet to explain how the morphology of cells determines their behavior. But, of course, the spatial method of growing new tissue appears to be cheaper and simpler than the signal-chemical "cultivation".