Ball, S.G., Bayley, C., Shuttleworth, C.A., and Kielty, C.M. 2010. Neuropilin-1 regulates platelet-derived growth factor receptor signaling in mesenchymal stem cells. Biochem J. 427: 29-40. pubmed
A major ambition of modern medicine is the ability to repair or regenerate any damaged tissue. To achieve this aim, one of the crucial challenges is the formation of new blood vessels. While recreating tissues may appear to be science fiction, increasing advances in adult stem cell research are bringing this possibility nearer to reality.
Unlike most other cells in our body, stem cells can replicate themselves many times over a long period, but their function has not yet been decided. What makes stem cells so promising for tissue regeneration, is their ability to turn into a specialised cell, a process known as differentiation. These differentiated cells, such as bone, muscle or nerve cells, have specialised internal structures which enable them to perform specific tasks.
A key objective is to identify what tells a stem cell to remain unspecialised, or instruct it to differentiate into a particular cell type. Like the specialised internal structures of differentiated cells, the tissues they form have distinctive external environments. These tissue specific environments produce signals, which can act like sign posts, to inform the stem cell where it is located and may direct it towards a distinct destination or differentiation fate. One important set of signals are small soluble molecules known as growth factors, these can only bind to and activate particular receptors on the surface of a cell, which may instruct the cell to do something.
We have previously shown that activation of platelet-derived growth factor receptors on the surface of adult stem cells, play a prominent role in stem cell recruitment and differentiation into cells which form blood vessels. More recently, we have identified another receptor on the surface of stem cells, called neuropilin-1, which was shown to be essential for regulating platelet-derived growth factor receptor activation and the formation of blood vessel-like structures by stem cells.
These findings enhance our knowledge of how stem cells can be regulated by growth factors to control their ability to form new blood vessels. A thorough understanding of what regulates a stem cell to differentiate to a specific cell type is crucial for the future success of cell-based tissue regeneration therapies.