TY - JOUR
T1 - The receptor for urokinase plasminogen activator is present in plasma from healthy donors and elevated in patients with paroxysmal nocturnal haemoglobinuria
AU - Rønne, E
AU - Pappot, H
AU - Grøndahl-Hansen, J
AU - Høyer-Hansen, G
AU - Plesner, T
AU - Hansen, N E
AU - Danø, K
PY - 1995/3
Y1 - 1995/3
N2 - The urokinase plasminogen activator (uPA) is a proteolytic enzyme which converts the proenzyme plasminogen to the active serine protease plasmin. A cell surface receptor for uPA (uPAR) is attached to the cell membrane by a glycosyl-phosphatidylinositol anchor. Binding of uPA to uPAR leads to an enhanced plasmin formation and thereby an amplification of pericellular proteolysis. We have shown previously that uPAR is expressed on normal blood monocytes and granulocytes, but is deficient on affected blood monocytes and granulocytes in patients with paroxysmal nocturnal haemoglobinuria (PNH), and that uPAR is present in plasma from these patients. In this study a newly established sensitive enzyme-linked immunosorbent assay (ELISA) has been applied for quantitation of uPAR in plasma. Unexpectedly, we found that uPAR is not only present in PNH plasma but also in plasma from healthy individuals. In 39 healthy individuals the mean plasma-uPAR value +/- SD was 31 +/- 15 pM, median 28 (range 11-108), and the corresponding value for six PNH patients was 116 +/- 67 pM, median 90 (range 61-228). The elevated uPAR-level in PNH patients was highly significant (Mann-Whitney test; P < 0.0001), and may possibly contribute to the propensity for thrombosis in PNH by inhibition of the fibrinolytic system. Binding of pro-uPA by uPAR in plasma may interfere with the appropriate binding of pro-uPA to cell-bound uPAR and therefore inhibit cell-associated plasmin generation and fibrinolysis. It is likely that the uPAR in normal plasma reflects the overall level of activity of the uPAR-mediated cell surface proteolysis. The present ELISA may be used for studies of uPAR levels in plasma from patients with conditions in which this activity might be increased, such as cancer and inflammatory disorders. Future studies will determine if uPAR in plasma is a parameter of clinical importance in these diseases.
AB - The urokinase plasminogen activator (uPA) is a proteolytic enzyme which converts the proenzyme plasminogen to the active serine protease plasmin. A cell surface receptor for uPA (uPAR) is attached to the cell membrane by a glycosyl-phosphatidylinositol anchor. Binding of uPA to uPAR leads to an enhanced plasmin formation and thereby an amplification of pericellular proteolysis. We have shown previously that uPAR is expressed on normal blood monocytes and granulocytes, but is deficient on affected blood monocytes and granulocytes in patients with paroxysmal nocturnal haemoglobinuria (PNH), and that uPAR is present in plasma from these patients. In this study a newly established sensitive enzyme-linked immunosorbent assay (ELISA) has been applied for quantitation of uPAR in plasma. Unexpectedly, we found that uPAR is not only present in PNH plasma but also in plasma from healthy individuals. In 39 healthy individuals the mean plasma-uPAR value +/- SD was 31 +/- 15 pM, median 28 (range 11-108), and the corresponding value for six PNH patients was 116 +/- 67 pM, median 90 (range 61-228). The elevated uPAR-level in PNH patients was highly significant (Mann-Whitney test; P < 0.0001), and may possibly contribute to the propensity for thrombosis in PNH by inhibition of the fibrinolytic system. Binding of pro-uPA by uPAR in plasma may interfere with the appropriate binding of pro-uPA to cell-bound uPAR and therefore inhibit cell-associated plasmin generation and fibrinolysis. It is likely that the uPAR in normal plasma reflects the overall level of activity of the uPAR-mediated cell surface proteolysis. The present ELISA may be used for studies of uPAR levels in plasma from patients with conditions in which this activity might be increased, such as cancer and inflammatory disorders. Future studies will determine if uPAR in plasma is a parameter of clinical importance in these diseases.
KW - Chromatography, Affinity
KW - Enzyme-Linked Immunosorbent Assay
KW - Hemoglobinuria, Paroxysmal/blood
KW - Humans
KW - Plasminogen Activators/analysis
KW - Receptors, Cell Surface/analysis
KW - Receptors, Urokinase Plasminogen Activator
KW - Recombinant Proteins/blood
KW - Reference Values
KW - Reproducibility of Results
KW - Thrombophlebitis/etiology
U2 - 10.1111/j.1365-2141.1995.tb08366.x
DO - 10.1111/j.1365-2141.1995.tb08366.x
M3 - Journal article
C2 - 7734357
SN - 0007-1048
VL - 89
SP - 576
EP - 581
JO - British Journal of Haematology
JF - British Journal of Haematology
IS - 3
ER -