1Laboratory of Structural Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
This study explores how sulfated glycolipids, like sulfatides, help cells stick together. It finds that proteins like laminin and thrombospondin bind to sulfatides, which is important for cell adhesion. Laminin helps cells attach more easily, even at low sulfatide levels, by linking cell receptors to sulfatides. Thrombospondin, however, inhibits this adhesion. Fucoidan, a sulfated polysaccharide, blocks laminin and thrombospondin binding but not von Willebrand factor. The study also shows that melanoma cells need high sulfatide density to attach directly, but laminin allows attachment at lower densities. These findings suggest sulfatides play a key role in cell adhesion through different mechanisms depending on the protein involved.
You might also read
Articles linked to this work by shared authors, journal, and citation graph.
Area of Science:
Background:
Cell adhesion involves multiple glycoproteins and glycolipids. Sulfated glycolipids like sulfatides are known to interact with cell surface receptors. However, the specific roles of sulfatides in adhesion remain unclear. Earlier studies showed sulfatides bind to laminin, thrombospondin, and von Willebrand factor. Yet, the mechanisms of these interactions differ across proteins. The role of sulfated polysaccharides in modulating these interactions has not been fully clarified. Some studies suggest fucoidan inhibits certain glycoprotein binding. The effects of sulfatides on melanoma cell adhesion are still debated. This uncertainty motivates further investigation into sulfatide-mediated adhesion pathways.
Purpose Of The Study:
This study aims to clarify the roles of sulfated glycolipids in cell adhesion. Specifically, it investigates how laminin, thrombospondin, and von Willebrand factor interact with sulfatides. The researchers seek to determine how sulfated polysaccharides influence these interactions. They also examine the effects of sulfatides on melanoma cell attachment and spreading. The study focuses on the differences between laminin- and thrombospondin-mediated adhesion. Understanding these differences could reveal distinct adhesion mechanisms. The goal is to identify how sulfatides function in both direct and protein-mediated adhesion. This work addresses the lack of clarity in sulfatide interaction dynamics.
Sulfatides mediate cell adhesion by interacting with laminin and thrombospondin. Laminin enhances adhesion by crosslinking receptors to sulfatides.
Fucoidan inhibits binding of laminin and thrombospondin to sulfatides but not von Willebrand factor.
Direct adhesion requires high sulfatide density, while laminin-dependent adhesion works at low density.
Thrombospondin inhibits both direct and laminin-dependent melanoma cell adhesion to sulfatides.
Main Methods:
The study uses glutaraldehyde-fixed erythrocytes to test glycoprotein binding to sulfatides. Researchers assess adhesion by measuring agglutination and cell spreading on plastic surfaces. They employ sulfated polysaccharides like fucoidan to test for inhibition of binding. Antibodies against thrombospondin’s sulfatide-binding domain are also used. Cultured cell lines are tested for attachment and spreading on sulfatide-coated surfaces. The effects of varying sulfatide density are evaluated. Laminin is introduced to observe its effect on adhesion dynamics. The study compares laminin and thrombospondin interactions with sulfatides.
Main Results:
Laminin, thrombospondin, and von Willebrand factor bind strongly to sulfatides. Fucoidan inhibits laminin and thrombospondin binding but not von Willebrand factor. Thrombospondin adsorbed on plastic promotes melanoma cell attachment and spreading. Fucoidan and anti-thrombospondin antibodies inhibit spreading but not attachment. Sulfatides, unlike neutral glycolipids or gangliosides, support cell attachment and spreading. High sulfatide density is needed for direct melanoma cell adhesion. Laminin enhances adhesion by crosslinking cell receptors to sulfatides. Thrombospondin inhibits both direct and laminin-dependent adhesion to sulfatides.
Conclusions:
Sulfatides mediate cell adhesion through interactions with laminin and thrombospondin. Laminin enhances adhesion by linking cell receptors to sulfatides. Thrombospondin inhibits adhesion rather than enhancing it. The presence of sulfatides is necessary for melanoma cell attachment. Laminin requires low sulfatide density for adhesion, while direct adhesion needs high density. Fucoidan inhibits laminin and thrombospondin binding but not von Willebrand factor. These findings suggest distinct mechanisms for laminin- and thrombospondin-mediated adhesion. The study confirms sulfatides play a role in both types of adhesion.
Laminin enhances adhesion by crosslinking cell surface receptors to sulfatides adsorbed on surfaces.
The study suggests sulfatides mediate adhesion via distinct mechanisms for laminin and thrombospondin.