Collagenase production by guinea pig megakaryocytes in vitro.
Cultured guinea pig bone marrow megakaryocytes were found to secrete a 92-kd collagenase that was detected by digestion of gelatin in a polyacrylamide substrate gel assay. Neither casein or bovine serum albumin were digested by this enzyme. The enzyme is a neutral metalloprotease. Its secretion is increased by thrombin (1.0 U/ml) and phorbol myristate acetate (10 ng/ml) and is unaffected by prostaglandin E1 (10 microM). In the absence of serum, gelatinase secretion is inhibited, but it can be stimulated by cytochalasin D (1.0 microgram/ml). Gelatinase activity in the medium from megakaryocytes cultured on rat tail collagen gel is decreased. Medium from megakaryocytes cultured on Matrigel contains a second gelatinase of 90 kd. Addition of the tetrapeptide RGDS to the cultures on Matrigel blocks the appearance of the 90-kd gelatinase. Platelets contained both a 92- and a 90-kd gelatinase that was detected only after thrombin activation. The results indicate that megakaryocytes can secrete a collagenase, and its secretion may be in part controlled by interaction with the extracellular matrix. The appearance of the 90-kd gelatinase may be associated with megakaryocyte maturation and platelet formation.
Leven
R M
RM
Research Medicine and Radiation Biophysics Division, Lawrence Berkeley Laboratory, University of California, Berkeley 94720.
Yee
T
T
D000818:Animals; D001854:Bone Marrow Cells; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000502:physiology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008533:Megakaryocytes / Q000201:enzymology*; D003012:Microbial Collagenase / Q000096:biosynthesis*; D008970:Molecular Weight
D003012:Microbial Collagenase