The ability of our bodily tissues to effectively repair cellular damage caused by environmental agents (viruses, bacteria, toxins, dietary factors etc) is critical for prevention of further damage or infection and for the healthy restoration of organ function. Key to tissue repair is the formation of temporary scars and contraction of wounds in order to "wall off" sites of damage while tissue healing takes place. If tissues suffer repeated damage over extended periods of time then scars are modified such that they are more difficult to break down during healing and they can spread to affect other parts of the organ. This is known as "fibrosis" and it can progress to the stage where the normal architecture and function of an organ is transformed to such an extent that it fails and the only current treatment options are transplantation or palliative care. Ageing appears to reduce the ability of organs to repair normally and as a result fibrosis is becoming more common in the general population, with recent estimates suggesting it underlies up to 40% of all deaths in the developed world. At present we have no proven effective therapies or preventative treatments for tissue fibrosis in any organ system. The liver is the organ responsible for detoxification and plays a major role in clearance of pathogens, however cells in the liver are equally susceptible to damage and infection as those in other parts of the body. As a consequence the liver is particularly susceptible to fibrosis where toxins or pathogens persist, and as we age when the regenerative capacity of the liver begins to falter. Chronic liver disease is currently the only common cause of death that is on the rise in the UK, with 16,000 deaths reported in 2008 and worryingly the trend is towards disease developing in people in their middle-life years. An effective antifibrotic that halts the development of scars and/or that helps break down existing scars in the liver would have a major impact on morbidity and mortality in patients with chronic liver disease. The research proposed in this application for a 5-year grant will build on work in the laboratory of the PI and his team that has identified a specialised cell in the diseased liver that promotes the formation, maintenance and spread of scars. This cell is known as a liver myofibroblast and it is generated chiefly by alterations in the properties and behaviour of liver cells that normally function to store Vitamin A. Upon injury or infection these so called "hepatic stellate cells" transform into myofibroblasts that produce vast quantities of scar tissue and are able to proliferate and migrate to cause fibrosis in the liver. The PI has been part of an international research effort that has confirmed that manipulating hepatic stellate cell-derived myofibroblasts can halt and even reverse fibrosis. The challenge for the next 5 years that will be tackled by the research team is to illuminate biochemical signals that regulate myofibroblast fate and function with the aim of finding biochemical "Achilles heels" that can be manipulated to stop or even hopefully reverse fibrosis. The research will use a combination of human cell culture, relevant mouse disease model systems and diseased human liver tissues to identify which signals can be manipulated to bring about antifibrotic effects. The team will use this knowledge to look for either existing drugs or new compounds (by chemical library screening) to find safe and effective treatments. This ambitious goal will be facilitated by a strong working partnership between the research team and the global biopharmaceutical company GlaxoSmithKline (GSK), the latter having a dedicated team of 40+ scientists working on discovery and development of antifibrotics at its Stevenage site. GSK will lend support with manpower, access to specialised scientific knowhow and provision of compounds and research tools as well as providing routes for translation to the clinic.