Neutrophil rolling altered by inhibition of L-selectin shedding in vitro.
The L-selectin adhesion molecule is involved in guiding leukocytes to sites of inflammation. L-selectin is cleaved by an unusual proteolytic activity at a membrane-proximal site resulting in rapid shedding from the cell surface. Although it has been demonstrated that L-selectin mediates, in part, the early event of leukocyte rolling under hydrodynamic flow, the contribution of shedding to L-selectin function has remained unknown. Here we show that hydroxamic acid-based metalloprotease inhibitors block L-selectin downregulation from the cell surface of stimulated neutrophils, without affecting Mac-1 mobilization or general neutrophil activation, and inhibit cleavage of L-selectin in a cell-free system. Unexpectedly, the hydroxamic acid-based inhibitors reduced neutrophil rolling velocity under hydrodynamic flow, resulting in increased neutrophil accumulation. These results suggest that L-selectin is cleaved in seconds--much faster than previously suspected--during the process of rolling under hydrodynamic flow, and that shedding of L-selectin may contribute significantly to the velocity of leukocyte rolling. L-selectin shedding during rolling interactions may be physiologically important for limiting leukocyte aggregation and accumulation at sites of inflammation.
Walcheck
B
B
Departments of Immunological and Inflammatory Diseases, Boehringer Ingelheim Pharmaceuticals Inc., Ridgefield, CT 06877, USA.
Kahn
J
J
Fisher
J M
JM
Wang
B B
BB
Fisk
R S
RS
Payan
D G
DG
Feehan
C
C
Betageri
R
R
Darlak
K
K
Spatola
A F
AF
Kishimoto
T K
TK
D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D010450:Endopeptidases / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D066298:In Vitro Techniques; D019041:L-Selectin / Q000187:drug effects / Q000502:physiology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D018375:Neutrophil Activation; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D019007:P-Selectin / Q000502:physiology
D004151:Dipeptides; D006877:Hydroxamic Acids; C099147:KD-IX 73-4; D019007:P-Selectin; D019041:L-Selectin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010450:Endopeptidases; D004121:Dimethyl Sulfoxide