Mesenchymal stem cells originate in the bone marrow, and are capable of differentiating into bone, cartilage, or fat cells depending on a variety of factors. A recent paper has found that cell shape plays a role in how these stem cells differentiate. When the mesenchymal stem cells are grown in shapes corresponding to higher contractility of the actin cytoskeleton, they are more likely to differentiate into bone cells, while cells in shapes of lower contractility are more likely to become fat cells. Image above shows cells grown in flower (top) or star (shapes). Cells on the left are stained for actin (green), focal adhesion protein vinculin (red), and DNA (blue); cells in the middle are stained for myosin. The heat maps on the right show high contractility in the star shaped cells, at the concave regions between the points of the star shape.
Reference: Kristopher A. Kilian, Branimir Bugarija, Bruce T. Lahn, and Milan Mrksich. Proc Natl Acad Science, 2010. 107(11): 4872–4877. doi: 10.1073/pnas.0903269107. Authors’ PNAS paper can be found here.