Telling Mesenchymal Stem Cells Where to Go

Birmingham, Alabama, USA -

Stem cell migration is an important issue. In situations like bone marrow transplantation for hematpoietic reconstitution, the hematopoietic stem cells are "told" to home to the bone marrow of the recipient by virtue of molecules such as SDF-1 which are secreted by bone marrow stromal cells.

The signals that guide mesenchymal stem cells to home to target tissue are still under investigation. A very useful advancement in the field would be genetically engineering specific molecules on stem cells so as to "instruct them" to go to where they are needed with a high rate of efficiency.

This is what the authors of a recent paper (Kumar et al. Bone homing of mesenchymal stem cells by ectopic {alpha}4 integrin expression.FASEB J. 2007 Jul 10) did. Specifically, the integrin CD49d was transiently transfected to mesenchymal stem cells and cells were injected into recipient mice. As expected a highly selective migration of the modified mesenchymal stem cells to the bone was observed. The mesenchymal stem cells were demonstrated to generate both osteoblasts and osteocytes in vivo, as well as to maintain other properties of mesenchymal stem cells.

The approach used by these authors will most definately be expanded in the future in order to cause tissue specific trophism of stem cells that are administered therapeutically.