Heparin oligosaccharides bind L- and P-selectin and inhibit acute inflammation

Abstract

Initial attachment of leukocytes to the vessel wall at sites of inflammation is supported by a family of carbohydrate-binding adhesion molecules called the selectins. Selectin ligands include sialyl-Lewis x (sLex, Neu5Ac alpha 2–3Gal beta 1–4[Fuc alpha 1–3]GlcNAc--) and related structures. We report here that defined heparin oligosaccharides interact with the selectins. Heparin chains containing four or more monosaccharide residues inhibited the function of L- and P-selectin, but not E-selectin, in vitro. In a competition enzyme-linked immunosorbent assay measuring inhibition of solution-phase selectin-Ig fusion proteins (selectin-Ig) binding to immobilized bovine serum albumin-sLex neoglycoprotein, a heparin-derived tetrasaccharide mixture inhibited 50% of L- and P-selectin-Ig binding (IC50) at 200 +/- 40 mumol/L and 850 +/- 110 mumol/L, respectively. A single hexasulfated tetrasaccharide (delta UA2S alpha 1–4GlcNS6S alpha 1–4IdoA2S alpha 1- 4GlcNS6S) was particularly active against L- and P-selectin-Ig (IC50 = 46 +/- 5 mumol/L and 341 +/- 24 mumol/L). By comparison, the tetrasaccharide sLex was not inhibitory at concentrations up to 1 mmol/L. In cell adhesion assays, heparin tetrasaccharides reduced binding of neutrophils to COS cells expressing P-selectin but not to COS cells expressing E-selectin. They also blocked colon cancer cell adhesion to L- and P-selectin but not E-selectin. In a model of acute inflammation, intravenously administered heparin tetrasaccharides diminished influx of neutrophils into the peritoneal cavities of thioglycollate-treated mice. We conclude that heparin oligosaccharides, including non-anticoagulant tetrasaccharides, are effective L- and P- selectin inhibitors in vitro and have anti-inflammatory activity in vivo.

Heparin-Protein Interactions

“…Selectin interactions may also be involved in the metastasis of certain epithelial cancers 204. Although the putative ligand on the endothelium responsible for the interaction of leukocytes with selectins is the carbohydrate antigen sialyl Lewis X (SLe x ), heparan sulfate has also been shown to play a role in this interaction 153, 205. Heparan sulfate interacts with L‐ and P‐selectin, but not E‐selectin 153, 206.…”

“…The P‐selectin‐binding heparan sulfates include chains with less highly modified domains 206. Heparin tetrasaccharides specifically block the interactions of L‐ and P‐selectins with SLe x ‐containing ligands demonstrating anti‐inflammatory activity in vivo, and also prevent colon cancer cell adhesion to L‐ and P‐selectin 205…”

Heparin-Protein-Wechselwirkungen

“…Selectinwechselwirkungen sind möglicherweise an der Metastasierung bestimmter Epithelcarcinome beteiligt 204. Der mutmaßliche Ligand für die Wechselwirkung von Leukocyten mit Selectinen am Endothel ist zwar das Kohlenhydrat‐Antigen Sialyl‐Lewis‐X (SLe x ), doch auch Heparansulfat spielt hierbei eine Rolle 153, 205. Heparansulfat wechselwirkt mit L‐ und P‐Selectin, nicht aber mit E‐Selectin 153, 206.…”

“…Die P‐Selectin‐bindenden Heparansulfate enthalten Ketten mit weniger stark modifizierten Domänen 206. Indem sie die Wechselwirkungen von L‐ und P‐Selectinen mit SLe x ‐haltigen Liganden spezifisch blockieren, wirken Heparin‐Tetrasaccharide in vivo entzündungshemmend und verhindern zudem die Adhäsion von Darmkrebszellen an L‐ und P‐Selectin 205…”

Low molecular weight heparin (tinzaparin) vs. placebo in the treatment of mild to moderately active ulcerative colitis

“…Heparin exhibits a broad range of immunomodulatory and anti‐inflammatory properties which could help to reverse the endothelial dysfunction that may be important in initiating and perpetuating inflammatory bowel disease 13 . In a murine model of acute inflammation, heparin oligosaccharides reduced neutrophil rolling and accumulation at the site of inflammation, an activity which seems to depend on inhibition of selectins, a family of carbohydrate‐binding adhesion molecules involved in the early steps of inflammation 14 …”