Fibrinolysis-independent role of plasmin and its activators in the haematopoietic recovery after myeloablation.
Proteinases have been implicated in the mobilization of haematopoietic progenitor cells (HPCs) from the bone marrow (BM). Here, we report the involvement of the plasminogen (Plg) system in the haematopoietic recovery following chemotherapy. By using gene-deficient mice, we found that plasmin and its activators tPA and uPA play a role in the haematopoietic recovery upon delivery of the cytotoxic agent 5-fluoro-uracil (5-FU). The impaired haematopoietic 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 haematopoietic recovery upon cytotoxic myeloablation.
Tjwa
Marc
M
Vesalius Research Center, VIB, Leuven, Belgium.
Moura
Rute
R
Moons
Lieve
L
Plaisance
Stephane
S
De Mol
Maria
M
Jansen
Sandra
S
Dewerchin
Mieke
M
Verfaillie
Catherine
C
Carmeliet
Peter
P
D000818:Animals; D016465:Bone Marrow Purging / Q000379:methods*; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism; D005341:Fibrinolysin / Q000378:metabolism*; D005342:Fibrinolysis / Q000187:drug effects; D005472:Fluorouracil / Q000494:pharmacology; D006410:Hematopoiesis / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D010958:Plasminogen / Q000172:deficiency / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000378:metabolism*; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
D005340:Fibrinogen; D010958:Plasminogen; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; D005472:Fluorouracil