Characterization of hyaluronic acid interaction with calcium oxalate crystals: implication of crystals faces, pH and citrate.

Interaction between hyaluronic acid (HA) present at the surface of tubular epithelial cells and calcium oxalate monohydrate (COM) crystals is thought to play an important role in kidney stone formation. AFM-based force spectroscopy, where HA is covalently attached to AFM-probes, was used to quantify the interaction between HA and the surfaces of COM crystals. The work of adhesion of the HA-probe as well as the rupture force of single HA molecules were quantified in order to understand the molecular regulation of HA binding to COM crystals.

Staphylococcus aureus SigB activity promotes a strong fibronectin-bacterium interaction which may sustain host tissue colonization by small-colony variants isolated from cystic fibrosis patients.

Genes encoding cell-surface proteins regulated by SigB are stably expressed in Staphylococcus aureus small-colony variants (SCVs) isolated from cystic fibrosis (CF) patients. Our hypothesis is that CF-isolated SCVs are locked into a colonization state by sustaining the expression of adhesins such as fibronectin-binding proteins (FnBPs) throughout growth. Force spectroscopy was used to study the fibronectin-FnBPs interaction among strains varying for their SigB activity.

AFM as a tool to probe and manipulate cellular processes.

The exploration of molecular processes governing physiological functions has significantly benefited from the emergence of novel nanoscaled techniques. Atomic force microscopy in force measurement mode can be used to investigate a multitude of cellular events in individual living cells with great sensitivity. Precise regions of the plasma membrane can be examined in relation to particular signalling pathways activated by a mechanical stimulus.

Single-molecule dynamic force spectroscopy of the fibronectin-heparin interaction.

The integrity of cohesive tissues strongly depends on the presence of the extracellular matrix, which provides support and anchorage for cells. The fibronectin protein and the heparin-like glycosaminoglycans are key components of this dynamic structural network. In this report, atomic force spectroscopy was used to gain insight into the compliance and the resistance of the fibronectin-heparin interaction.

PKC-induced stiffening of hyaluronan/CD44 linkage; local force measurements on glioma cells.

Interaction of cells with hyaluronan (HA) rich extracellular matrix involves the membrane receptor CD44. HA-CD44 interactions are particularly important in the development of glioma pathogenesis for its implication in tumor cells spreading. Highly motile states rely on the spaciotemporal regulation of HA-CD44 interactions occurring in specific cytoskeletal-supported membrane organization such as microvilli or the leading edge observed in migrating cell.