Deciphering collagen mineralization process by dynamic imaging in liquid

Description du projet

Observer la formation osseuse en temps réel à l’échelle nanométrique

Les propriétés mécaniques exceptionnelles des os sont le résultat d’interactions qui se produisent à l’échelle nanométrique entre les fibrilles de collagène de type I et l’hydroxyapatite, mais le processus complexe de la formation osseuse n’est pas encore entièrement compris. Le projet DYNAMIN, financé par l’UE, a pour ambition de comprendre le mécanisme de dépôt minéral ainsi que les interactions entre les différents types de cellules. Les scientifiques utiliseront la microscopie électronique en phase liquide qui, contrairement aux approches traditionnelles, leur permettra de visualiser les changements dynamiques au cours de la formation osseuse. Par ailleurs, l’identification de biomolécules clés fournira des informations importantes sur la régulation du processus de minéralisation osseuse.

Objectif

Bone is a complex nanocomposite with outstanding mechanical properties arising from the nanoscale interaction between its two main building blocks: type I collagen fibrils and hydroxyapatite crystals. Despite its clinical relevance, the mechanisms governing bone formation are still poorly understood, mainly due to the complexity of the processes. During bone formation and remodeling, non-collagenous proteins and proteoglycans act synergistically to regulate the mineral deposition process, participating in multiple signaling pathways involving regulatory molecules, osteoblasts and osteoclasts.
Many of the studies performed until now relayed into simplified in vitro models that hardly represent this complexity. Furthermore, methods traditionally applied only provide snapshots of this process, unable to extract dynamic information. To really understand the mechanisms regulating bone mineralization, we need to simultaneously visualize its different components in its context, to be able to monitor their interactions.
In this project, I propose to combining liquid-phase electron microscopy and immunolabelling, with which I aim to bring together dynamic imaging of a complex biochemical process and the identification of the biomacromolecules involved. By recreating the mineralization conditions inside the liquid cell, I aim to obtain real time data on nucleation sites, crystal growth and mineralization dynamics. The combination of dynamic imaging with immunogold will allow me to monitor the direct interaction of these regulatory molecules with the mineral particles at nanoscale resolution. By means of this new exciting approach I expect to provide unprecedented data on the processes of bone formation and take a step forward in the application of LPEM in biological materials.