MICA: Molecular drivers of fibrosis at the hepatic epithelial-mesenchymal barrier

Chronic liver disease (CLD) is a major cause of death, being responsible for over one million early fatalities in 2010, equating to 2% of all deaths worldwide. These statistics are reliably expected to rise over the coming decade, in major part as a consequence of non-alcoholic fatty liver disease (NAFLD), a dangerous pathology of the liver that affects 20% of the global population, which is closely associated with diabetes and obesity. Up to 30% of patients with NAFLD can progress to end stage disease known as cirrhosis. Therefore, cirrhosis may potentially be impacting on 5% of the world population including millions of children and young adults. In addition to this shocking statistic, 350 million people are infected with the hepatitis B virus leading to 40,000 deaths per annum in Europe alone, 150 million are infected with hepatitis C causing 500,000 liver-related deaths each year. Furthermore, CLD carries a high risk of liver cancer, now the second most common cause of cancer-related deaths worldwide, preceded only by lung cancer. While arguably NAFLD may respond to lifestyle interventions; lack of robust clinical guidelines and challenges associated with patient compliance for dietary/exercise changes necessitate a multifaceted approach for care of CLD. Paramount to this approach is the urgent and unmet need for medicines that slow, halt or even reverse the disease pathway to cirrhosis and associated risk of cancer. This MICA research programme will benefit from collaboration of world-leading liver disease investigators of the Newcastle Fibrosis Research Group (NFRG) and the scientific power and resources of the global pharmaceutical company GSK. The aim of the proposed research is to understand how damage to liver cells leads to cirrhosis and to translate this research into the design of new medicines and diagnostics that bring benefit to CLD patients.

Study of the biology of CLD reveals commonalities that characterize the disease irrespective of the cause of liver injury. These characteristics include repetitive damage to hepatocytes which are the main cell type in the liver, unresolved inflammation and aberrant liver tissue remodeling involving the progressive laying-down of non-functional scar tissue that gradually replaces functional liver cell mass. Scar-formation is known as fibrosis and can occur in any organ where there is repetitive cellular damage. Fibrotic scars in the liver are produced by myofibroblasts generated by 'activation' of resident specialized hepatic stellate cells in response to liver damage. Modulating the activities of the myofibroblast has the potential to halt or even reverse fibrosis. Based on preliminary data from NFRG and GSK we propose that repetitive damage to hepatocytes changes their molecular characteristics such that they repeatedly signal a need to generate scar tissue to nearby myofibroblasts. We aim to discover the nature of the molecular changes occurring in damaged hepatocytes and identify the signals they communicate to the myofibroblast. As NAFLD is such a major global concern an important focus will be placed on determining how the uptake of excess fats into hepatocytes alters their biology to stimulate fibrosis.

Much of the research will make use of human liver tissue made possible by recent exciting technological advances in the NFRG laboratories. It is now possible to 'model' NAFLD in thin slices of liver tissue. Using this advance alongside modern molecular biology approaches we will discover so-called 'epigenetic' drivers that operate within fat-laden hepatocytes to stimulate fibrosis. These drivers can be exploited for the design of new blood tests that tell us which NAFLD patients are at risk from cirrhosis as well as guiding us on where to target the development of new therapies. By partnering with GSK there is tremendous opportunity for discoveries emerging from the research to be translated to healthcare products for patient benefit.

Chronic liver disease (CLD) results from unresolved damage. Background and preliminary investigations suggest that unresolved hepatocyte damage promotes inflammatory and fibrogenic cross-talk to resident mesenchymal cells (myofibroblasts) culminating in progression to cirrhosis. The goal of the research will be to illuminate the mechanisms by which unresolved hepatocyte stress stimulates fibrosis and in doing so unlock new therapeutic solutions and biomarkers for monitoring disease progression. Our overarching hypothesis is that unresolved hepatocyte stress promotes epigenetic and transcriptional reprogramming to establish a de-differentiated epithelium (i.e. hepatocytes) that stimulates fibrosis progression via soluble mediators that modulate myofibroblast phenotype and function. We will address this hypothesis by tackling three key objectives:

1. Discover mechanisms of hepatocyte epigenome and transcriptome remodeling that drive fibrosis.

2. Define hepatocyte-myofibroblast fibrogenic cross-talk pathways.

3. Unlock intercellular IL-1a/CCL2 fibrogenic signaling for therapeutic intervention in chronic liver disease.

The 1st objective will employ a bespoke human liver bioreactor to model disease processes occurring in hepatocytes in NAFLD. Epigenetic and transcriptome adaptions to lipid stress will be mapped, functionally interrogated, validated in patients and translated to new blood-based diagnostics. In objective 2 we will discover how a novel regulatory pathway involving the transcription factors c-Rel, Snail and Twist operate in hepatocytes to establish a 'secretome' communicating fibrosis-stimulating signals to myofibroblasts and identify key regulatory components of the 'secretome'. Hepatocyte-derived IL-1a is one such component which in objective 3 we will study by genetic approaches as a potent stimulator of myofibroblast-monocyte fibrogenic signaling.

The main beneficiaries and their potential benefits from the research will be:

1. THE MILLIONS OF PEOPLE WORLDWIDE LIVING WITH A CHRONIC LIVER DISEASE ALONG WITH THEIR FAMILIES AND HEALTH CARE TEAMS. At the end of the programme we expect to have discovered biomarkers that diagnose progressive fibrosis in these patients and collaborated with industrial partners to develop these biomarkers into minimally invasive blood-based tests. We anticipate discovery of new therapeutic targets that will be exploited either by our MICA partner or other industrial collaborators for drug discovery, the end goal being medicines that slow, halt or reverse fibrosis to prevent progression to cirrhosis. Previous MRC-funded research in the NFRG has led to (i) an EME-funded clinical study examining the therapeutic potential of Losartan in NAFLD patients with established fibrosis, (ii) identification of epigenetic markers in NAFLD patient plasma that are included in a Newcastle-led Innovative Medicines Initiative challenge (LITMUS) focused on development of industry-standard diagnostics for NAFLD for which Jelena Mann and Fiona Oakley are named co-investigators. Similar routes to impact will be exploited for future discoveries that have potential for direct patient benefit.

2. PHARMACEUTICAL AND BIOTECHNOLOGY COMPANIES DEVELOPING ANTI-FIBROTIC MEDICINES AND FIBROSIS BIOMARKERS. The MICA will be in partnership with GSK who are giving a cash sum of £500k to the research and additional 'in-kind' contributions that will justify first options on commercial development of discoveries from the research. In the event that GSK pass on IP, we will initially approach other UK-based companies in the sector which from our ongoing interactions through FibroFind, the commercial arm of NFRG, we will be fully aware of ongoing R&D aspirations in the fibrosis field. Such companies include Medimmune, UCB, Pfizer and Mission Therapeutics all of which are currently working with FibroFind. Hence, the research has potential to enhance UK biopharma R&D and UK economy. We will facilitate this route to impact through high profile journal publications, international conferences that are attended by industry partners and highlight notices of our discoveries and technology advances on the NFRG website, twitter and via posts on Derek Mann's LinkedIn profile which currently has around 800 followers inclusive of members working in the biopharma sector.

3. ACADEMIC BENEFICIARIES IN THE FIELDS OF HEPATOLOGY, EPIGENETICS AND WOUND HEALING AND FIBROSIS. The NFRG are widely recognized for the quality, reproducibility and translational potential of their research outputs. We will ensure that discoveries are reported in preliminary form at relevant international conferences, on preprint servers (e.g bioRxiv) prior to full publication, this ensuring these beneficiaries have full opportunity to validate findings in their own laboratories and determine relevance of our findings in allied field (e.g. fibrosis of other organ systems).

4. EARLY CAREER RESEARCHERS (ECRS) WORKING IN THE NFRG LABORATORIES. The NFRG have a strong track record for supporting and mentoring ECRs towards academic careers. Recent examples are (i) Dr Mudjat Zeybel who carried out PhD in the NFRG is now Associate Professor and PI at Koch University, Istanbul, Turkey; (ii) Dr Caroline Wilson who was a postdoc on the current MICA was promoted this year to a Newcastle University Research Fellow, this the entry point for academic PI status; (iii) Dr Ana Moles, a postdoc in the NFRG was awarded a Ramon y Cajal fellowship to establish her research career at Spanish Research Council in Barcelona focused on renal fibrosis; (iv) Dr Lee Borthwick, a former Marie Curie Fellow was promoted to Lecturer in the NFRG. In total, Derek Mann has mentored nine alumni to academic posts in the UK, Spain, Turkey and China, this route to impact will continue to have priority status and will be facilitated by award of the new MICA