Mobilization and homing of bone marrow stem cells after stroke

Generally, bone marrow stem cells (BMSCs) reside in the bone marrow, where the microenvironments maintain a dynamic balance between self-renewal and differentiation. However, BMSCs can also be forced into the blood, a process termed mobilization, which is clinically used to harvest large number of cells for transplantation. On the other side, stroke-induced local and systemic pathological responses also lead to the mobilization of BMSCs to peripheral blood and then “homing” to the damaged regions, which is considered as an important regenerative process. In this chapter, we summarize current understanding of the physiological and pathological mechanisms that guide BMSC mobilization and homing to the damaged brain. The underlying cellular and molecular mechanisms, which largely depend on an interplay between chemokines, chemokine receptors, intracellular signaling, adhesion molecules, and proteases, are also discussed. Increasing the number of BMSC mobilization and homing is critical for the promotion of stroke cell-based therapies.