title: A direct role for C1 inhibitor in regulation of leukocyte adhesion.
abstract: Plasma C1 inhibitor (C1INH) is a natural inhibitor of complement and contact system proteases. Heterozygosity for C1INH deficiency results in hereditary angioedema, which is mediated by bradykinin. Treatment with plasma C1INH is effective not only in patients with hereditary angioedema, but also in a variety of other disease models, in which such therapy is accompanied by diminished neutrophil infiltration. The underlying mechanism has been explained primarily as a result of the inhibition of the complement and contact systems. We have shown that C1INH expresses the sialyl-Lewis(x) tetrasaccharide on its N-linked glycan, via which it binds to E- and P-selectins and interferes with leukocyte-endothelial adhesion in vitro. Here we show that both native C1INH and reactive center cleaved C1INH significantly inhibit selectin-mediated leukocyte adhesion in several in vitro and in vivo models, whereas N-deglycosylated C1INH loses such activities. The data support the hypothesis that C1INH plays a direct role in leukocyte-endothelial cell adhesion, that the activity is mediated by carbohydrate, and that it is independent of protease inhibitory activity. Direct involvement of C1INH in modulation of selectin-mediated cell adhesion may be an important mechanism in the physiologic suppression of inflammation, and may partially explain its utility in therapy of inflammatory diseases.
authors.affiliation: The CBR Institute for Biomedical Research, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Shenghe
authors.initials: S
authors.lastname: Cai
authors.forename: Vandana S
authors.initials: VS
authors.lastname: Dole
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bergmeier
authors.forename: Jennifer
authors.initials: J
authors.lastname: Scafidi
authors.forename: Hanping
authors.initials: H
authors.lastname: Feng
authors.forename: Denisa D
authors.initials: DD
authors.lastname: Wagner
authors.forename: Alvin E
authors.initials: AE
authors.lastname: Davis
mesh_terms: D000818:Animals; D016466:CHO Cells; D002272:Carcinoembryonic Antigen / Q000378:metabolism; D002448:Cell Adhesion / Q000276:immunology; D002464:Cell Migration Inhibition; D003174:Complement C1 Inactivator Proteins / Q000502:physiology*; D003171:Complement Pathway, Classical; D006224:Cricetinae; D019040:E-Selectin / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology; D018922:HL-60 Cells; D006801:Humans; D036904:Leukocyte Rolling / Q000276:immunology; D007962:Leukocytes / Q000166:cytology* / Q000201:enzymology / Q000276:immunology*; D008024:Ligands; D051379:Mice; D008807:Mice, Inbred BALB C; D020556:Neutrophil Infiltration / Q000276:immunology; D010538:Peritonitis / Q000139:chemically induced / Q000276:immunology / Q000473:pathology; D013864:Thioglycolates / Q000008:administration & dosage
chemical_list: D002272:Carcinoembryonic Antigen; D003174:Complement C1 Inactivator Proteins; D019040:E-Selectin; D008024:Ligands; D013864:Thioglycolates