Journal of Cellular and Molecular Medicine vol:13 issue:11-12 pages:4587-4595
Proteinases have been implicated in the mobilization of hematopoietic progenitor cells (HPCs) from the bone marrow (BM). Here, we report the involvement of the plasminogen (Plg) system in the hematopoietic recovery following chemotherapy. By using gene deficient mice, we found that plasmin and its activators tPA and uPA play a role in the hematopoietic recovery upon delivery of the cytotoxic agent 5-fluoro-uracil (5-FU). The impaired hematopoietic recovery of Plg deficient (Plg(-/-)) mice after 5-FU was not rescued by depletion of fibrinogen, indicating that it was not due to defective fibrinolysis. Instead, loss of Plg impaired breakdown of fibronectin, VCAM-1 and laminin, BM matrix proteins involved in adhesion of HPCs to their BM microenvironment and in transendothelial migration of HPCs. These findings provide novel insights in how plasmin regulates hematopoietic recovery upon cytotoxic myeloablation.