Papers by charles lamontagne
Pflügers Archiv - European Journal of Physiology, 2007
The exploration of molecular processes governing physiological functions has significantly benefi... more 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. Similarly, subtle cellular movements induced by biochemical activation of specific membrane receptors can be detected in real time with excellent temporal and spatial resolution. The possibility to challenge locally and mechanically cell surface receptors also provides information on the control exerted by a cell over individual adhesion sites. Overall, this information is vital for an in-depth understanding of mechanisms related to cellular movement and morphological regulation. Lastly, atomic force microscope-based nanomanipulations on living cells have recently been proposed as a tool to influence and monitor cellular homeostasis by introducing specific molecular entities into or extracting them from the cytoplasm of individual cells. This review provides detailed examples on how such atomic force microscopy experiments can be conducted to investigate processes relevant to cell physiology.
Biochemical and Biophysical Research Communications, 2007
The integrity of cohesive tissues strongly depends on the presence of the extracellular matrix, w... more 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. We found that this interaction can be described by an energetic barrier width of 3.1 ± 0.2 Å and an off-rate of 0.2 ± 0.1 s À1. These dissociation parameters are similar to those of other carbohydrate-protein interactions and to off-rate values reported for more complex interactions between cells and extracellular matrix components. Our results indicate that the function of the fibronectin-heparin interaction is supported by its capacity to sustain significant deformations and considerable external mechanical forces.
Label-Free Monitoring of Cell Signalling Processes Through AFM-Based Force Measurements
Atomic Force Microscopy of Live Cells, 2011
Characterization of hyaluronic acid interaction with calcium oxalate crystals: implication of crystals faces, pH and citrate
Journal of Molecular Recognition, 2011
Interaction between hyaluronic acid (HA) present at the surface of tubular epithelial cells and c... more 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. Our results reveal that HA adsorbs to the crystal surface in physiological conditions. We also observed increased adhesion when the pH is lowered to a value that increases the risk of kidney stone formation. HA adhesion to the COM crystal surface can be suppressed by citrate, a physiological inhibitor of stone retention currently used in the treatment and prevention of kidney stone formation. Interestingly, we also observed preferential binding of HA onto the [100] face versus the [010] face, suggesting a major contribution of the [100] faces in the crystal retention process at the surface of tubular epithelial cells and the promotion of stone formation. Our results clearly establish a direct role for the glycosaminoglycan HA present at the surface of kidney tubular epithelium in the process of COM crystal retention.
PKC-induced stiffening of hyaluronan/CD44 linkage; local force measurements on glioma cells
Experimental Cell Research, 2008
Interaction of cells with hyaluronan (HA) rich extracellular matrix involves the membrane recepto... more 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. We used AFM-based force measurement to probe the HA-CD44 interaction at localized regions at the surface of living glioma cells expressing high level of the CD44 standard isoform. We show that unstimulated cells interact with HA over their entire surfaces and are highly deformable when force is exerted on individual HA molecules bound to membrane CD44 receptors. Conversely, in PKC-activated cells the probed interactions are concentrated at the leading edge of the cells with reduced membrane deformability. Taken together, our results show that PKC-enhanced motility in glioma cells is associated with a redistribution of CD44 receptors at the leading edges concomitant with a stiffer anchoring of CD44 to the cell surface involving the actin cytoskeleton.
Characterization of hyaluronic acid interaction with calcium oxalate crystals: implication of crystals faces, pH and citrate
Journal of Molecular Recognition
Interaction between hyaluronic acid (HA) present at the surface of tubular epithelial cells and c... more 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. Our results reveal that HA adsorbs to the crystal surface in physiological conditions. We also observed increased adhesion when the pH is lowered to a value that increases the risk of kidney stone formation. HA adhesion to the COM crystal surface can be suppressed by citrate, a physiological inhibitor of stone retention currently used in the treatment and prevention of kidney stone formation. Interestingly, we also observed preferential binding of...
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Papers by charles lamontagne