Postal Address :
Croix du Sud, 4-5
E-mail : Yves Dufrêne
Tel. +32 10 47 36 00
Secretariat +32 10 47 35 88
Carnoy Bldg (SC12)
Floor 04, room C455
Postdoc positions are available !
Microbiology at the nanoscale
Our goal is to push the limits of force nanoscopy beyond state-of-the-art to establish this nanotechnology as an innovative platform in biofilm research. By developing new tools, we wish to understand how pathogens use their surface molecules to guide cell adhesion and trigger infections, and to develop anti-adhesion strategies for treating biofilm-infections.
"Knowledge is limited. Imagination encircles the world.” ― A. Einstein
May 7, 2018
Mechanobiology: Staphylococcus aureus under tension !
Staphylococcus aureus is an important bacterial pathogen which is a leading cause of biofilm-associated infections on indwelling medical devices. Biofilms are currently estimated to be involved in more than 65 % of hospital-acquired infections. There is evidence that bacterial adhesion and biofilm formation are favored under high physical stress, but how this is achieved at the molecular level is not known. In a study published in PNAS, our team, together with the Trinity College Dublin, has elucidated the mechanism by which S. aureus responds to mechanical tension. We focused on the bacterial surface protein ClfA, and on its interaction with fibrinogen, a blood protein that rapidly covers implanted medical devices. Using atomic force microscopy, we showed that ClfA behaves as a force-sensitive molecular switch that potentiates staphylococcal adhesion under mechanical stress. The adhesion of ClfA is weak at low tensile force, but is dramatically enhanced by mechanical tension, as observed with catch bonds. Strong bonds are inhibited by a peptide mimicking Fg, which offers prospects for the development of antiadhesion therapeutics. These findings are of biological significance because they explain at the molecular level the ability of ClfA to promote bacterial attachment under high physiological shear stress. This study emphasizes the role of mechanobiology in staphylococcal biofilms, a topic that we also discusses in a recent perspective article in Science.
For more details, see https://uclouvain.be/fr/sciencetoday/actualites/le-stress-du-staphylocoque-dore.html
April 24, 2018
New ACS Nano paper: Mechanical forces guiding Staphylococcus aureus cellular invasion
Invasion of mammalian cells by S. aureus involves fibronectin-dependent bridging between FnBPs on the bacterial surface and α5β1 integrins in the host cell membrane, but the fundamental forces involved are poorly understood. With our colleagues from the University of Pavia, we have used state of the art single-cell and single-molecule experiments to quantify the molecular forces engaged in this three component interaction, revealing that the fibronectin bridge between FnBPs and the α5β1 integrin is mechanically strong.
March 30, 2018.
New perspective article in Science: Force matters in hospital-acquired infections
Building up on an outstanding paper by Gaub et al. we discuss how extremely strong forces help staphylococci to colonize biomaterials and infect humans.
December 5, 2017.
Physical stress activates the adhesive function of Staphylococcus aureus surface protein clumping factor B
Staphylococcus aureus colonizes the skin and the nose of humans and can cause various disorders, including superficial skin lesions and invasive infections. During nasal colonization, the S. aureus surface protein clumping factor B (ClfB) binds to the squamous epithelial cell envelope protein loricrin, but the molecular interactions involved are poorly understood. In a new paper published in mBio, we unravel the molecular mechanism guiding the ClfB-loricrin interaction. We show that the ClfB-loricrin bond is remarkably strong, consistent with a high affinity "dock, lock and latch" binding mechanism. We discover that the ClfB-loricrin interaction is enhanced under tensile loading, thus providing evidence that the function of a S. aureus surface protein can be activated by physical stress.