Assessment of megakaryocyte migration and chemotaxis.

Cell migration is a highly integrated multistep process that plays an essential role during development and disease. Megakaryocytes (MKs) are specialized precursor cells that produce platelets and release them into the circulation. MK migration from the proliferative osteoblastic niche within the bone marrow (BM) environment to the capillary-rich vascular niche is an essential step for platelet production. Among the chemokines that may play a central role in cell migration, the stromal cell-derived factor 1α (SDF1α) also known as CXCL12 has been described to act as a potent chemoattractant for MKs. This biological effect is mediated by the SDF1α receptor CXCR4 (Fusin), which is expressed on haematopoietic stem cells, MKs and platelets. The Dunn chemotaxis chamber in conjunction with the time-lapse microscopy is a powerful tool that enables the user to observe directly the morphological response of cells to chemoattractant in real time. This chapter describes the Dunn chemotaxis chamber to study the migration of primary BM-derived MKs in response to a gradient of SDF1α. In combination with genetically modified mice, this provides a powerful approach to directly investigate the role of specific proteins in MK migration and chemotaxis.