Hyaluronan (HA) assembly and its Role in Bone Morphogenic Protein-7 Driven Antagonism of Renal Fibrosis

Organ failure resulting from fibrosis is the predominant cause of chronic diseases in our population including kidney disease, liver disease, lung and heart disease. However no treatments exist that can halt or reverse fibrosis and prevent organ damage. This research aims to identify targets that can potentially alleviate or reverse fibrosis, with the aim of developing new therapies to prevent end-organndamage in at-risk patients.

Myofibroblast are the principle fibrosis-producing cells. They are produced by the circulating factor TGF-beta-1 through transformation of epithelial cells and fibroblasts. BMP7 is another circulating factor, which opposes TGF-beta-1-driven fibrosis. However, neither direct blocking of TGF-beta-1, nor treatment with BMP7 are viable therapies as they cause significant side effects. Thus we need to further study these two circulating factors to identify more targetted therapy with less side effects. Our department has previously shown that TGF-beta-1-driven formation of myofibroblasts is dependent on how cells make and assemble a third molecule, Hyaluronan (HA). We also know that BMP7 can assemble HA differently to TGF-beta-1. Our aim is to carry out detailed studies to determine the effects of BMP-7 on how fibroblasts/epithelial cells generate, assemble and handle HA; thus allowing us to differentiate between good and bad HA. This will allow us to prevent formation of myofibroblasts, thus enabling us to identify therapies that can prevent or reverse fibrosis in at risk patients.

Hyaluronan (HA) is a matrix polysaccharide involved in regulation of cellular processes, and demonstrates increased expression in renal disease. TGF-beta-1 promotes epithelial mesenchymal transition and fibroblast to myofibroblast differentiation. These processes drive renal interstitial fibrosis, which predicts outcome in all renal diseases, and our previous studies have shown that both these processes are mediated by HA. BMP7 is a cytokine demonstrating reduced expression in renal disease. Evidence suggests it can both prevent and reverse TGF-beta-1-driven fibrosis. We have shown that BMP7 modifies cellular HA matrix and there is evidence that HA modulates BMP7 responses. The aim of this proposal is to investigate if the prevention and/or reversal of TGF-beta-1 responses by BMP7 are mediated by the effects of BMP7 on HA matrix.

The work will initially utilise fibroblast and renal epithelial cells models and encompass a variety of cell biology techniques to characterise BMP7-driven alterations in HA at a pericellular, cell-surface and cytoplasmic level and relate these changes to TGF-beta-1 driven regulation of cell phenotype. Furthermore, the in vivo applicability and relevance of our in vitro observations will then be investigated by identifying BMP7 driven alteration in HA and HA-related proteins in the kidney in an animal model of renal disease. This work will inform the next steps in terms of identifying suitable HA related targets for the development of knockout animal models, and aid in the development of new therapeutic strategies in progressive renal disease.

Progressive fibrosis in tissues and organs is the pathological process that underlies a significant number of chronic diseases in our populations. Prevention and/or reversal of this process is a major goal of research in across a variety of research disciplines including research into cardiovascular, renal, pulmonary and liver disease. Furthermore, research in this area can also be applicable to other areas including wound healing research, immuno-regulatory and cancer research. The work proposed in this application will thus potentially benefit other academic and scientific institutions through direct collaboration, as well as through dissemination via peer reviewed publications and presentation at scientific meetings.

The work outlined is specifically designed to identify new pathways and processes that can be potentially targeted to prevent and/or reverse a pro-fibrotic myofibroblast phenotype. Furthermore, the proposed work will validate altered expression of these targets in an animal model of renal disease, and in prevention and/reversal of progressive fibrosis in this model. If successful this could lead to future interventional animal studies that could ultimately translate into the bedside thus promoting public health and well being, as well as improving costs for treatment of patients with chronic kidney disease and chronic disease in general. The award will provide me with dedicated research time, supervision and mentorship at two leading research institutions that will facilitate towards my career development as an independent researcher. It will also provide training and mentorship for a post-doctoral research assistant, who will obtain extensive experience and transferable skills in a range of scientific techniques and methodologies valued by biotechnology companies, thus providing a skilled worker into the workforce.

Through its dissemination and through public engagement we also hope to inspire a new generation of scientists and researchers in this field, and in the field of medical research in general. Our research will be disseminated through liaison with the Cardiff University Communications and International Relations Division. Furthermore, the Institute of Nephrology itself holds a variety of public engagement programs including open days attended by renal patients and their relatives and hosting visits for A-level and work-experience students. A number of these students are able to join our laboratory for a four-week summer project through the Nuffield Foundation Bursary Scheme and many have proceeded to study medicine or biological sciences at university.