PhD Transfer Examination – Roxanne Fournier (Harrison lab)

PhD Transfer Exam

Tuesday October 11^th, 10:10 am – Room SW 403, University of Toronto at Scarborough

Roxanne Fournier (Harrison lab)

“Osteocyte Form and Function in Loading and Unloading Environments“

Abstract

Bone is a dynamic tissue composed of a variety of specialized cells such as osteocytes, which are known to regulate bone remodeling due to their mechanosensitive abilities. In space, mechanical stimuli normally sensed by these cells are absent which is highly unfavourable for their functioning. We propose that spaceflight inhibits the osteocyte’s ability to sense mechanical forces through morphological changes to its cytoskeleton and functional changes to its mechanosensory pathways. This may support why astronauts experience greater bone loss than controls subjected to bed-rest on Earth. The mechanisms involved in this unique disease have not been elucidated and will therefore be the focus of this research. To achieve this objective, osteocytes will be studied in a 3D bone-like matrix in vitro to determine gene, protein and morphological changes in conditions simulating microgravity and will be compared to simulated bed-rest controls and dynamic loading controls. Additionally, transcriptome analyses of these three conditions will be assessed for novel therapeutic gene targets. As a result, we will have a better understanding of astronaut osteoporosis which can be used to establish mitigation strategies for future space missions.