Membrane-grafted hyaluronan films: A well-defined model system of glycoconjugate cell coats

Universität Heidelberg, Heidelburg, Baden-Württemberg, Germany
Journal of the American Chemical Society (Impact Factor: 11.44). 06/2007; 129(17):5306-7. DOI: 10.1021/ja068768s
Source: PubMed

ABSTRACT We report on the creation of films of end-grafted hyaluronan, based on solid-supported lipid membranes. We characterize the layer thickness, the grafting density, the mechanical properties and the permeability of these highly hydrated and up to several hundred nanometer-thick monomolecular layers by quartz crystal microbalance with dissipation monitoring, by colloidal probe triple-wavelength reflection interference contrast microscopy, and by reflectometry. The two-dimensional assemblies thus created are expected to serve as versatile platforms to study, in a well-controlled and quantitative manner, the effect of hyaluronan-binding proteins on the structure, properties, and biological function of this type of films.


Available from: Pit Bingen, Jun 03, 2015
  • Source
  • [Show abstract] [Hide abstract]
    ABSTRACT: Spatially confined yet strongly hydrated assemblies made from the proteoglycan aggrecan and the polysaccharide hyaluronan (HA) are major, functionally important components of the pericellular space around chondrocytes, and in cartilage. To better understand, how mechanical properties arise from the supramolecular structure and dynamics of such assemblies, we have studied the effect of aggrecan on the physico-chemical properties of well-defined, planar HA brushes. From interaction studies by quartz crystal microbalance with dissipation monitoring and spectroscopic ellipsometry, and compression studies by combined colloidal probe atomic force/reflection interference contrast microscopy, we find that aggrecan readily intercalates into HA brushes in a reversible manner. Aggrecan induces a drastic swelling of HA brushes, generating self-assembled films of several micrometers in thickness that are highly hydrated (>99%), elastic and very soft. The Young modulus in the linear compression regime is well below 100 Pa, and reaches several kPa at strong compression. The implications of these findings for biological function are discussed.
    Soft Matter 01/2013; 9(44):10473. DOI:10.1039/c3sm51213d · 4.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Mammalian oocytes are surrounded by a highly hydrated hyaluronan (HA)-rich extracellular matrix with embedded cumulus cells, forming the cumulus cell-oocyte complex (COC) matrix. The correct assembly, stability and mechanical properties of this matrix, which are crucial for successful ovulation, transport of the COC to the oviduct and its fertilization, depend on the interaction between HA and specific HA-organizing proteins. Although the proteins inter-αinhibitor (IαI), pentraxin 3 (PTX3) and TNF-stimulated gene-6 (TSG-6) have been identified as being critical for COC matrix formation, its supramolecular organization and the molecular mechanism of COC matrix stabilization remain unknown. Here we used films of end-grafted HA as a model system to investigate the molecular interactions involved in the formation and stabilization of HA matrices containing TSG-6, IαI and PTX3. We found that PTX3 binds neither to HA alone nor to HA films containing TSG-6. This long pentraxin also failed to bind to products of the interaction between IαI, TSG-6 and HA, among which are the covalent HC·HA and HC·TSG-6 complexes, despite the fact that both IαI and TSG-6 are ligands of PTX3. Interestingly, prior encounter with IαI was required for effective incorporation of PTX3 into TSG-6-loaded HA films. Moreover, we demonstrated that this ternary protein mixture made of IαI, PTX3 and TSG-6 is sufficient to promote formation of a stable (i.e. cross-linked) yet highly hydrated HA matrix. We propose that this mechanism is essential for correct assembly of the COC matrix, and may also have general implications in other inflammatory processes that are associated with HA-crosslinking.
    Journal of Biological Chemistry 09/2014; DOI:10.1074/jbc.M114.568154 · 4.60 Impact Factor