Localization of anticoagulantly active heparan sulfate proteoglycans in vascular endothelium: antithrombin binding on cultured endothelial cells and perfused rat aorta
| Autor: | A. I. De Agostini, H Youssoufian, Robert D. Rosenberg, H S Slayter, Simon C. Watkins |
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| Jazyk: | angličtina |
| Rok vydání: | 1990 |
| Předmět: |
Male
Endothelium In Vitro Techniques Antithrombins Extracellular matrix Cell membrane Glycosaminoglycan Iodine Radioisotopes medicine Animals Blood Coagulation Aorta Glycosaminoglycans biology Cell Membrane Rats Inbred Strains Cell Biology Articles Protease inhibitor (biology) Cell biology Extracellular Matrix Rats Endothelial stem cell carbohydrates (lipids) Perfusion Microscopy Electron medicine.anatomical_structure Biochemistry Proteoglycan Chondroitin Sulfate Proteoglycans Cell culture biology.protein Autoradiography Proteoglycans Endothelium Vascular Heparitin Sulfate Heparan Sulfate Proteoglycans medicine.drug Protein Binding |
| Zdroj: | The Journal of Cell Biology |
| ISSN: | 1540-8140 0021-9525 |
| Popis: | We have studied the interaction of 125I-antithrombin (125I-AT) with microvascular endothelial cells (RFPEC) to localize the cellular site of anticoagulantly active heparan sulfate proteoglycans (HSPG). The radiolabeled protease inhibitor bound specifically to the above HSPG with a Kd of approximately 50 nM. Confluent monolayer RFPEC cultures exhibited a linear increase in the amount of AT bound per cell for up to 16 d, whereas suspension RFPEC cultures possessed a constant number of protease inhibitor binding sites per cell for up to 5 d. These results suggest that monolayer RFPEC cultures secrete anticoagulantly active HSPG, which then accumulate in the extracellular matrix. This hypothesis was confirmed by quantitative light and EM level autoradiography which demonstrated that the AT binding sites are predominantly located in the extracellular matrix with only small quantities of protease inhibitor complexed to the cell surface. We have also pinpointed the in vivo position of anticoagulantly active HSPG within the blood vessel wall. Rat aortas were perfused, in situ, with 125I-AT, and bound labeled protease inhibitor was localized by light and EM autoradiography. The anticoagulantly active HSPG were concentrated immediately beneath the aortic and vasa vasorum endothelium with only a very small extent of labeling noted on the luminal surface of the endothelial cells. Based upon the above data, we propose a model whereby luminal and abluminal anticoagulantly active HSPG regulate coagulation mechanism activity. |
| Databáze: | OpenAIRE |
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