CIR Seminar - Professor Chrissy Hammond

Professor Chrissy Hammond, Professor of Musculoskeletal Science at the University of Bristol

Talk Title: Building bone in a hurry: immune cells, matrix and the choreography of skeletal repair

Abstract: Fracture repair requires cells with very different functions to rapidly construct a mechanically competent tissue. We use zebrafish to watch this process unfold in vivo and to ask how events occurring immediately after injury influence the structure of the bone that is ultimately rebuilt. Our work identifies an unexpectedly constructive role for neutrophils during the earliest stages of fracture repair. Neutrophils accumulate rapidly at fractures, undergo NETosis and interact extensively with extracellular matrix, helping to establish a provisional environment in which subsequent repair takes place. Perturbing this early response, including through ibuprofen treatment, disrupts osteoblast recruitment, mineralisation and callus architecture and increases fracture non-union. I will discuss how these findings are changing the way we think about the inflammatory phase of skeletal repair, and then broaden the question to ask how robust this process remains across different biological contexts. In particular, I will explore how ageing alters repair and regeneration, why these two responses may fail differently, and how the timing and state of transient cell populations could shape the tissue that eventually emerges.

Bio: Chrissy Hammond is a Professor at the University of Bristol, where her lab uses zebrafish to understand how bones grow, age, break and put themselves back together again. Her research sits somewhere between cell biology, immunology, biomechanics and a persistent desire to watch biological processes happening in real time. The group combines live imaging with genetics, single-cell approaches and increasingly elaborate ways of measuring the structure and mechanics of bone, asking how the behaviour of individual cells becomes translated into functional tissue. Current interests include skeletal ageing, fracture repair and regeneration, the surprisingly complicated lives of neutrophils, and how biological timing influences repair. She is particularly fond of experiments that produce beautiful pictures and unexpected answers.