Collagen (I) homotrimer in age-related fibroses and tissue degeneration: evaluation as a stem cell biomarker

Collagen is the most abundant structural protein in the body. Collagen creates an environment within which cells reside and forms fibres that make tissues resilient to external stresses, for example during mechanical loading such as that occurs during normal locomotion. Collagen can be broken down and reformed by cells using biological enzymes; a normal process during growth and development. However, cancer cells invade tissues by degrading collagen whilst concurrently making their own non-degradable version of collagen, thereby creating a pathway for invasion. Non-degradable collagen has also been found in degenerative skeletal diseases such as osteoarthritis and osteoporosis as well as in fibrotic diseases including liver cirrhosis. The only other reports of non-degradable collagen are from embryonic cells or tissues, indicating that it might be produced by a type of stem cell and fulfil a normal biological function. Stem cells have the potential to form many different tissue types and their use has the potential to revolutionise approaches to regenerative medicine and tissue engineering. Embryonic stem cells can form all cell types in the body, but their use in research and in treatment trials is limited because of ethical considerations. Adult tissue stem cells are rare and may only be able to regenerate the tissue that they came from, but they could potentially be used to treat the patient from which they were isolated without subsequent immune rejection. The aim of this project is to determine whether non-degradable collagen is produced by embryonic and/or adult stem cells and to understand how cells control the genes responsible for this type of collagen production. This project will investigate how ageing affects the expression of these two forms of collagen and might predispose to disease. This research is important to characterise stem cells and to understand their role in the repair and regeneration of collagen-rich tissues. A clearer understanding of the role of particular types of collagen in ageing and disease would allow the development of biological markers for age- and disease-associated collagen. Such biological markers could be incorporated into tests to determine an individual's likelihood of developing diseases such as cancer, arthritis or osteoporosis. They could also be used to predict how quickly an individual might become frail and immobile in old age and to therefore tailor lifestyle recommendations (diet, exercise, built environment) and future anti-ageing medicines for particular groups. The results from this project would be informative for research programs that aim to use stem cells for transplantation or in tissue engineering.

Collagen (I) is the most abundant structural protein in vertebrates. The natural form of collagen (I) is a heterotrimer that assembles into large extracellular fibrils. Abnormal homotrimeric collagen (I) is resistant to protease-mediated degradation and is synthesised by cancer cells to create pathways for metastatic tissue invasion. Embryonic cells have been reported to produce collagen (I) homotrimers and in adults homotrimeric collagen (I) is also associated with fibrosis and connective tissue pathologies. This project proposes to test the hypothesis that that pathologies spanning fibrosis, osteoarthritis and tumour metastasis share a common stem/progenitor cell-mediated molecular mechanism involving the aberrant production of type I collagen homotrimers. The relative expression from the COL1A1 and COL1A2 genes in stem and progenitor cells will be determined by qRT-PCR and correlated with the relative amount of each collagen (I) alpha chain, assessed by metabolic labeling. Pathological tissues will be screened for homotrimer production and the contribution of self-renewing cell populations to homotrimer production determined in parallel cell cultures isolated from such tissues. Tissue explants and cell cultures will be treated with a genomic demethylating agent, to determine whether COL1A2 promotor methylation is widely used to reduce COL1A2 mRNA expression and promote the formation of alpha1 homotrimers. Finally the relative expression of each of the collagen (I) genes will be assessed in model systems from foetal to mature stages of development to determine how age-related epigenetic changes could predispose to skeletal disease. This data will be important for understanding how to harness stem cells for tissue repair and regeneration, without adverse effects on tissue function. The project is also highly relevant to the development of biomarkers of age-related frailty and stiffness and to predict the development of musculoskeletal disease.

This section lists potential impacts of this research project in addition to the expected advancement of scientific knowledge and benefits to the wider academic community described in the section on Academic Beneficiaries.

UK INDUSTRY: This is a basic research project that aims to characterise the cellular and molecular mechanisms of abnormal collagen (I) homotrimer production in fibrotic and degenerative diseases and in ageing. It is anticipated that research findings could be used to develop biomarkers of age-related disease, frailty and functional decline. Proteomic, cellular/epigenetic or gene expression analysis could initially be applied to tissue biopsies and used as diagnostic or predictive biomarkers. Future population-based epidemiological studies could then be used to assess blood and urine samples as relatively non-invasive biomarker sources and to correlate fibrotic and degenerative diseases with abnormal collagen production. Successful validation and commercialisation of such biomarkers would benefit the UK economy either through the creation of new spin-out companies or by adding value to existing SMEs. Uptake of this technology by large pharmaceutical companies would be expected to indirectly benefit the UK through licence or sale of intellectual property rights, further investment and/or job creation.

CONSULTANTS AND PATIENTS: This research could lead to improved diagnostic tests for fibrotic and degenerative diseases as well as a wider range of options for predicting disease progression. This would benefit medical practitioners aiming to improve patient care and patients looking for a rapid diagnosis and appropriate treatment for their symptoms. Improvements in stem cell therapies resulting from this research would also lead to benefits for patients in terms of tissue regeneration and transplantation treatment options.

PUBLIC HEALTH: Part of this research proposal addresses the link between ageing and predisposition to develop fibrotic and degenerative diseases. Development of epigenetic screening at the COL1A1 and COL1A2 loci could allow prediction of the likelihood of an individual developing fibrotic and degenerative disease at particular ages and new methods of assessing biological rather than chronological age. Stratified treatment, targeted disease screening and inexpensive health and lifestyle advice could then be used to reduce the impact of biological disease predisposition on an individual's health and well being. Improvements in health in an increasingly elderly population would produce wide-ranging societal benefits.

CLINICAL APPLICATION OF STEM CELLS: This research proposal seeks to address whether and which types of stem cells are a source of abnormal collagen (I) homotrimers. The results of this research have implications for the use of stem cells to treat human disease or in the generation of tissue replicas for transplantation. Regulatory bodies governing the development of stem cell therapies which include the MHRA (Medicines and Healthcare Products Regulatory Agency), the HSE (Health and Safety Executive), the HTA (Human Tissue Authority), the GTAC (Gene Therapy Advisory Committee) and the Human Fertilisation & Embryology Authority would be expected to benefit from this research through an improved understanding of the safety/risks of using particular types of stem cells in clinical situations.

SKILLS TRANSFER: This project proposes to employ a post-doctoral research associate for three years. This PDRA will use and develop skills in biochemical and molecular biological laboratory techniques as well as the use of stem cells in research. The researcher will interact with industry through the proposed impact activities and will be involved in carrying out the communications plan for the project. This will allow transfer of a skilled individual with their associated knowledge and expertise to the industrial, academic or government/regulatory workforce at the end of the project.