Researchers at Queen Mary University of London identified a mechanosensitive tendon cell population within the interfascicular matrix, shedding new light on tendinopathy mechanisms and offering an experimental framework to study how physical environments influence tendon health across human and animal tissues.
Tendons are complex biological structures made up of distinct regions with varying physical environments rather than one uniform population of cells. A team of scientists at Queen Mary University of London has focused on the cells within the interfascicular matrix, known as the IFM, which is the softer tissue that connects the collagen bundles or fascicles making up a tendon. Their recent research, published in Advanced Science
, demonstrates that these specific cells are highly sensitive to changes in their mechanical surroundings.
Isolating Cell Populations and Mechanical Stiffness
To understand how tendon tissue responds to ageing or injury, the research team successfully isolated and maintained populations of both IFM cells and fascicular matrix cells. This laboratory culture framework allowed them to compare how the two distinct cell populations react when exposed to varying levels of mechanical stiffness. While the fascicular matrix cells remained largely unchanged under those conditions, the IFM cells proved exceptionally responsive.
When placed on stiff substrates, the IFM cells altered their internal structure, rapidly changed the expression of genes linked to tendon function and extracellular matrix production, and exhibited a drop in their proliferative capacity. Crucially, when researchers returned these same cells to softer, IFM-like substrates, their morphology and ability to proliferate recovered successfully, alongside the restoration of certain gene expression changes.
Insights from Dr Simon Grossemy and Professor Hazel Screen
The findings offer fresh perspective on tendinopathy, a condition causing persistent pain and impaired movement in humans and various animals. Because tendons naturally change in structure and stiffness during disease, understanding individual cellular responses is critical for researchers investigating tendon degeneration.
Our findings show that different tendon cells can respond very differently to changes in their mechanical environment. This is important because tendons can undergo changes in their structure and stiffness during disease, and we need to understand how individual cell populations respond to those changes.
Dr Simon Grossemy, lead researcher from Queen Mary University of London
The study also highlights the importance of the physical microenvironment in sustaining normal cellular behavior. Professor Hazel Screen, the Principal Investigator on the research, noted the significance of the observed recovery when cells were placed back into softer conditions.
The recovery we observed when IFM cells were returned to a softer environment was particularly interesting. It highlights how the physical environment is an important factor in maintaining the behaviour and characteristics of these cells.
Professor Hazel Screen, Principal Investigator
Implications for Human Medicine and Equine Athletics
Tendinopathy remains difficult to treat largely because the underlying biological processes of tendon degeneration are not yet fully understood. By isolating a mechanosensitive cell population, this work provides an experimental platform to examine how environmental shifts inside a tendon drive disease or support tissue health.
Beyond human healthcare, the findings extend to animal medicine. Tendon injuries are a major concern for horses, whose tendons experience substantial mechanical forces during athletic activity and movement. A clearer picture of how tendon cells react to their physical surroundings enables researchers to explore biological recovery processes across multiple species.
Future Directions in Tendon Biology
Although the study does not establish that IFM cells directly cause tendinopathy or deliver a new clinical treatment, it establishes an exciting new experimental framework
for investigating these questions. Furthermore, the newly developed defined laboratory culture framework helps maintain vital IFM cell characteristics in vitro
, overcoming the challenge of cells changing their behavior once removed from natural tissue.
The research team hopes these insights will advance detailed knowledge of tendon biology and pave the way for targeted approaches to prevent, manage, and repair tendon damage in people and animals.
