title: High-molecular weight kininogen is present in cultured human endothelial cells: localization, isolation, and characterization.
abstract: The presence of high-molecular weight (mol wt) kininogen was demonstrated in cultured human endothelial cells derived from the umbilical cord by immunofluorescence techniques. Cultured human endothelial cells contain 58 +/- 11 ng (n = 16) high-mol wt kininogen/10(6) cells as determined by an enzyme-linked immunosorbent assay (ELISA) specific for high-mol wt kininogen. High-mol wt kininogen was isolated from cultured human endothelial cells by immunoaffinity chromatography. Nonreduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that endothelial cell high-mol wt kininogen consisted of five protein bands with mol wts of 95,000, 85,000, 65,000, 46,000, and 30,000 daltons. Immunoblotting of the endothelial cell high-mol wt kininogen by using specific antisera against the heavy and light chain indicated that the 95,000-, 85,000-, and 65,000-dalton bands consisted of the heavy and light chain whereas the 46,000- and 30,000-dalton bands reacted only with the anti-light chain antiserum. Immunoprecipitation studies performed with lysed, metabolically labeled endothelial cells and monospecific antisera directed against high-mol wt kininogen suggested that high-mol wt kininogen is not synthesized by the endothelial cells. Endothelial cells cultured in high-mol wt kininogen-free medium did not contain high-mol wt kininogen. These studies indicate that endothelial cell high-mol wt kininogen was proteolytically cleaved in the culture medium and subsequently internalized by the endothelial cells. Binding and internalization studies performed with 125I-labeled, proteolytically cleaved, high-mol wt kininogen showed that endothelial cells can indeed bind and internalize proteolytically cleaved high-mol wt kininogen in a specific and saturable way.
authors.affiliation: Department of Haematology, University Hospital Utrecht, The Netherlands.
authors.forename: F
authors.initials: F
authors.lastname: van Iwaarden
authors.forename: P G
authors.initials: PG
authors.lastname: de Groot
authors.forename: J J
authors.initials: JJ
authors.lastname: Sixma
authors.forename: M
authors.initials: M
authors.lastname: Berrettini
authors.forename: B N
authors.initials: BN
authors.lastname: Bouma
mesh_terms: D002478:Cells, Cultured; D002846:Chromatography, Affinity; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006801:Humans; D007231:Infant, Newborn; D007704:Kininogens / Q000276:immunology / Q000302:isolation & purification*; D008970:Molecular Weight; D014470:Umbilical Cord
chemical_list: D007704:Kininogens