Sialylated O-glycans and L-selectin sequentially mediate myeloid cell rolling in vivo.
Leukocyte rolling precedes firm adhesion and emigration in inflammatory cell recruitment. Both P-selectin, an endothelial lectin that binds to sialylated O-glycans containing sialyl-Lewisx (sLex) on the granulocyte surface, and leukocyte L-selectin have been shown to mediate leukocyte rolling in vivo. Here, we investigate rolling of isolated human neutrophils (PMN), HL-60 promyelocytes, and an L-selectin-transfected cell line (300.19-L) during trauma-induced inflammation in rat mesenteric venules. HL-60 cells, which express no L-selectin but abundant sLex, rolled effectively immediately after abdominal surgery. HL-60 cell rolling was almost completely abolished by pretreatment with sialidase or monoclonal antibody (MoAb) AM-3 recognizing sLex, and was reduced by about 80% by O-sialoglycoprotein-endopeptidase (OSGP). By contrast, 300.19-L cells rolled poorly immediately after surgery but rolled well between 40 and 120 minutes after surgery. Their rolling was completely inhibited by the blocking L-selectin MoAb LAM1-3, but not by a binding control MoAb. PMN express both L-selectin and clustered, sialylated glycoproteins including P-selectin glycoprotein ligand-1 (PSGL-1). PMN showed effective rolling at all times, which was abolished by sialidase or MoAb AM-3 pretreatment during the first 30 minutes after surgery, but not later, when PMN rolling was largely L-selectin-dependent. We conclude that in trauma-induced inflammation, a two-step mechanism accounts for most of myeloid cell rolling, which initially requires O-glycans and subsequently depends on L-selectin function.
Ley
K
K
Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville 22908, USA.
Zakrzewicz
A
A
Hanski
C
C
Stoolman
L M
LM
Kansas
G S
GS
D000818:Animals; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000502:physiology*; D002465:Cell Movement; D002478:Cells, Cultured; D005260:Female; D006098:Granulocytes / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D019041:L-Selectin; D009504:Neutrophils / Q000502:physiology*; D011134:Polysaccharides / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014699:Venules / Q000502:physiology
D015815:Cell Adhesion Molecules; D011134:Polysaccharides; D019041:L-Selectin