Opportunities to modulate extracellular matrix secretion and assembly for long term health

Lead Research Organisation: University of Manchester
Department Name: School of Biological Sciences

Abstract

Collagen is the most abundant structural protein in the body, making up 1/3 of our mass. It is formed into centimetre-long fibrils. This organisation gives collagen-rich tissues their differing properties (e.g. flat plywood lattices in stretchable skin and parallel bundles in rope-like tendons). Changes to collagen underpin many of the changes we associate with ageing, such as loss of skin elasticity, poor wound healing, fibrosis, susceptibility to fracture and osteoarthritis. Most people will experience reduced quality of life due to a failure of collagen maintenance. Yet, despite its fundamental importance, we still do not fully understand how synthesis of the precursor procollagen, export from the cell, assembly and maintenance of the collagen network are regulated.

This programme brings together researchers from the Universities of Manchester and Bristol, with complementary expertise in key aspects of collagen biology. We have discovered new mechanisms of collagen secretion, shown that secretion and assembly of the collagen matrix is controlled by the circadian rhythm (the internal clocks in our tissues that cycle in response to day and night patterns of activity and light), and defined how the immune system modulates the repair of a collagen matrix on wounding. Now, we wish to exploit our multidisciplinary skills that include fundamental aspects of cell and tissue biology, integrated experiments using in vitro and in vivo models, circadian biology, mathematical modelling, and novel synthetic scaffolds to answer major questions in matrix biology. Working together, sharing tools, personnel, and expertise we will be able to make more impact than we could individually.

We have 5 specific aims:

1. Use cells and zebrafish to determine how the precursor of collagen, called procollagen, passes through the cell. We will define the role of key protein machineries in the Golgi apparatus (the central sorting station through which everything that is secreted by cells passes).

2. Understand how transport of newly-made collagen is coordinated in space and time. We will determine how the circadian rhythm regulates the formation, holding pattern, and export of collagen.

3. Derive a mathematical framework that links information on how collagen is made to how it is used in the body. This will allow us to predict how changes to any part of the pathway that makes and assembles collagen affects other components, which we can test in cells or animals.

4. Test how the collagen network responds to damage, in injury and ageing, and test how day/night rhythm and our immune system influence this. We will make minor injuries into translucent zebrafish and use fluorescently-labelled collagen to watch how cells respond and how the collagen network is rebuilt.

5. We will produce 3D scaffolds that mimic how old and young tissues perform. We know that tissues become stiffer as we age; using custom built scaffolds we can test how young cells respond to scaffolds that resemble old tissue and vice versa.

This project will also train the next generation of scientists, exposing the early-career researchers to state-of-the-art technology and equipment and to tailored training that will benefit them in their careers. Working together offers enhanced opportunities to engage with industry, clinicians and the wider public to ensure the work has the maximum impact.

As well as furthering our understanding of how the collagen matrix is assembled and regulated, the programme will generate significant new tools that will benefit the wider academic community. These include new reagents that will enable visualisation of how collagen moves through the cell, new tools to define how remodelling of collagen in skin, tendon and bone occurs during development and following injury, and new synthetic scaffolds that could be used industrially or clinically to help in repair of major skin wounds, or tendon and ligament repair following injury.

Technical Summary

Vertebrates contain 30% collagen, which occurs in the extracellular matrix mostly as fibrous networks and provides the principal supporting structures of tissues. The importance of collagen is exemplified in conditions where too little collagen leads to tissue frailty, e.g. poor wound repair and musculoskeletal diseases, which together affect 1-in-4 people in the UK. Conversely, excess collagen causes incurable fibrosis, which compromises organ function and is associated with 45% of deaths including cardiovascular disease and cancer. Effective treatments for these collagen-related conditions would have major health and socioeconomic impact.

Much of our current understanding of collagen comes from studies of the extracellular fibrils. These insoluble structures are highly ordered, contain associated components, and are centimeters in length and teradaltons in mass. Their scale and complexity make them refractory to conventional structural, molecular, and biochemical studies. Our vision is that studying newly discovered intracellular regulatory processes that control fibril formation will generate new insight into what underpins the loss of control, that contributes to so many facets of tissue pathology and disease.

To make this possible, work in our labs in Manchester and Bristol has led to technological innovations in making fluorescent collagens, imaging fibrils in wounds and at the plasma membrane, developing 3D cell culture models, and the first mathematical model of intracellular collagen trafficking. Together these will help us to test new hypotheses. We have also shown that collagen assembly is under circadian clock control. Achieving our vision relies on each member of our multidisciplinary team contributing to complementary aspects of this common research goal. We anticipate that our collective fresh approach will generate paradigm shifting discoveries that will have lasting benefit for fundamental discovery science, bioindustry and biomedicine.

Planned Impact

Collagen is the most abundant protein in mammalian systems and forms the primary source of tensile strength in connective tissues such as bone, cartilage, and tendons. This application seeks to address the fundamental biology of cell and tissue function by developing our understanding of the way in which cells make and shape their extracellular matrix (ECM).

Who might benefit and how?

Clinicians - Dysregulation of collagen is the hallmark of some of the most debilitating features of normal ageing and life-threatening diseases; insufficient collagen can abrogate the mechanical properties of tissues and is associated with poor wound repair (which costs the NHS £2.5 billion p.a.), as well as osteoarthritis (8 million sufferers in the UK (Versus Arthritis UK website)) and tendinopathy (1-in-4 over 40 y.o.) for which there are no effective treatments. Conversely, fibrosis - the dysregulated accumulation of collagen in place of functional tissue - is associated with 45% of all deaths (including cardiovascular disease and cancer). Progress in treating these diseases has been hindered because of poor understanding of how cells synthesise, maintain, and repair collagen-rich tissues. A deep understanding of the fundamental basic science of collagen homeostasis is an elusive cornerstone of biology. Our work could identify new targets for clinical genetics, extending to analysis of patient cohorts (such as ALSPAC) to derive new insight into onset and progression of bone and joint degeneration during ageing. Our systems to perturb and model the systems, notably in wound situations have significant potential for those working in these areas, both for acute wound treatment and in relation to fibrosis.

Industry - There is great interest in the possibility to subvert existing cellular pathways for therapeutic benefit. We have clear plans in place for direct engagement, but many others will derive value from our work in relation to engineering of cells and tissues for theraeutic benefit, for the production and refinement of synthetic scaffolds, and from our mathematical modelling work which we anticipate would be readily adaptable for related applications.

The general public - In addition to the broad benefits that understanding fundamental bioscience brings in the longer term (32x gross value added per public spend), this work addresses directly key areas of health that have the potential to impact both on acute genetic diseases as well as long term health of the general population. The potential for our work in terms of tissue repair and regeneration presents one opportunity to engage through our fundamental discovery science. Our image and movie data are also extremely useful for high impact public engagement through displays and exhibitions.

Bioscience researchers - This project includes considerable opportunity to train the researchers involved in areas that go beyond the day-to-day research methodology. We have strong track records in facilitating the placement of staff in areas outside our core research activity including in intellectual property management, public engagement, clinical trials, and research policy and management. This demonstrates that the environment provided by our labs as well, as our two Universities more widely, is highly conducive to career development of our staff beyond academic, basic science research alone and thus contributes to the economic development of the nation. Our programme is very data intensive - notably from imaging, proteomics, and genomics work - and the management and analysis of such large (terabyte) datasets is applicable to many areas of professional life. Combined with mathematical modelling, our work provides a showcase opportunity for integration of multiple technologies and approaches to address a fundamental and highly significant problem in the biosciences. We hope this will be relevant and of great interest to many.

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