Potential BBSRC funded studentship requiring CASE partner
If you have any partnering opportunities for regeNer8 members, please contact us.
Prof Jenny Southgate
Jack Birch Unit of Molecular Carcinogenesis
University of York
For further information on this opportunity, please contact Rekha Parmar.
Subject areas:
Cell Biology; Biochemistry and Molecular Biology; Human Biology
Specific research areas:
Cancer; regenerative medicine; tissue engineering; cell signalling; urology; mechanotransduction; wound repair; innate immunity; infection.
Overview of Research
Our aim is to understand the basis for the homeostatic regulation of proliferation versus differentiation in normal and regenerating epithelial tissues, and to relate this to understanding benign and neoplastic disease processes. To these ends, we have developed cell and tissue culture systems to study normal and disease processes in a human epithelial tissue, the urothelium. We use a wide range of techniques, including immunophenotyping, electrophysiology, cell signalling, genetic modification, transcriptomics, proteomics and computational modelling. Our objective is to find solutions to clinical problems by collaboration with clinicians and industry in areas of tissue engineering/regenerative medicine, oncology and urology.
Areas relevant to Regenerative Medicine
Biomaterials: We are investigating the development of biomaterials for soft tissue engineering, looking specifically at two aspects of bladder tissue engineering. Firstly, the use of inert biodegradable carriers to transfer in vitro-propagated urothelial cells from the laboratory to the surgical recipient. Secondly, the identification of natural or synthetic biomaterials that can function as a scaffold for tissue regeneration by cellularisation, either prior to implantation (in vitro "tissue engineering" strategy +/- bioreactors) or post grafting (in vivo cellularisation strategy). We also have an interest in biomaterial functionalisation - eg by incorporation of bioactive factors (this is in collaboration with Neil Cameron in Durham).
Stem cells: The urinary bladder is a target organ for regenerative and tissue engineering strategies that aim to restore urinary continence compromised as a result of congenital or acquired tissue damage. The bladder and associated tract is lined by urothelium, a highly-specialised self-renewing epithelium that has a low constitutive cell turnover rate and a large capacity for regeneration. We have developed methods to isolate normal human urothelial cells from urological specimens, expand them in serum-free culture and redifferentiate them into functional urothelial tissues. A porcine surgical model has been developed to test the principle of reconstructing the bladder using in vitro propagated urothelial cells.
Example studentship projects:
Engineered human bladder tissues: an in vitro platform for investigating normal and disease processes
The bladder and associated urinary tract are lined by a transitional epithelium known as urothelium. As well as being a highly regenerative tissue, urothelium functions as a physical urinary barrier, aided by specialised molecular features acquired during tissue differentiation. The self-regenerating and physical barrier properties of urothelium are critical: a compromised urothelial barrier results in symptoms of cystitis, including urinary urgency, inflammation and pain. This raises interesting questions as to the mechanisms that regulate the balance between tissue repair/regeneration versus restitution of differentiated tissue function. Understanding these basic questions is central to understanding and treating both benign and malignant diseases of the bladder.
Progress has been hindered by the lack of good normal and disease models of urothelium that are relevant to human. Recent advances in the in vitro culture and tissue engineering of human urothelium has provided potential new experimental systems.
The overall goal of this project is to exploit 2D and 3D human urothelial cell culture systems to develop and explore physiological models of normal and compromised human urothelium. The project will provide research training in a wide range of cellular, immunochemical and molecular techniques, including cell culture, gene/protein expression analysis, gene transduction and cell signalling pathway analysis.
The role of p63 in urothelial differentiation and stem cell function
The existence of adult progenitor/stem cells has been demonstrated in a variety of epithelial tissues. p63, a homologue of the tumour suppressor protein p53, is constitutively expressed in the progenitor cell compartment of several epithelial tissue types. Previous studies have reported that p63 is expressed in normal urothelium and its loss is associated with tumour progression in bladder cancer, whereas reports from in vivo studies have suggested that loss of p63 function prevents formation of a terminally-differentiated urothelium. The aim of the project is to knockdown p63 expression in normal human urothelial cells by retrovirus-mediated RNA interference in order to: 1) examine the role of p63 is normal urothelial cell growth and determine its capacity as a tumour suppressor protein, 2) understand the importance of p63 in the differentiation potential of urothelial cells and 3) identify whether p63 status can be used as a marker of urothelial progenitor cells.
Regulating growth, differentiation and survival in urothelium: the role of PPAR nuclear hormone receptor signalling.
The epithelial lining of the bladder, urothelium, is highly specialised to function as a urinary barrier, with a slow turnover rate, high regenerative capacity and a unique differentiation programme leading to expression of urothelium-specific proteins. The peroxisome proliferator activated receptors (PPARs) are highly expressed by urothelium and are implicated in the regulation of a number of key cellular processes, including proliferation, differentiation, apoptosis and carcinogenesis. We have shown that activation of PPARgamma is important in inducing the urothelial differentiation programme, but the roles of PPARalpha and PPARdelta are unknown. The purpose of the project is to study the consequences of PPARalpha and PPARdelta activation on urothelial cell phenotype and to examine the mechanisms by which pharmacological agonists with dual PPAR activity may be pro-carcinogenic to urothelial cells. The project will provide research training in a wide range of cellular, immunochemical and molecular techniques, including cell culture, gene microarray analysis and cell signalling pathway analysis.
Identification of human urothelial stem cells
The urothelium is the transitional epithelium that lines the bladder and associated urinary tract from the renal pelvis through to the proximal urethra. It comprises basal, intermediate and superficial cell layers. Specialised properties of the urothelium are important in supporting its function as a tight urinary barrier and are a critical precondition for bladder function and metabolic haemostasis. This barrier function is mainly achieved by the expression of selective claudins and urothelium-specific uroplakin proteins. Claudins regulate paracellular barrier function through formation of intercellular tight junctions, while uroplakins (UPK) form characteristic urothelial plaques on the apical superficial membrane to contribute to the transcellular barrier function. The urothelium is a mitotically quiescent tissue in situ with an extreme low turnover rate and a long lifespan of these cells. In response to injury, infection or other damage, the urothelium adopts a highly proliferative phenotype. Although there is assumed to be a resident progenitor population, no specific population has been identified yet that acts as a stem cell in human urothelium. The main aim of this project is to characterise the stem cell-like properties of proliferating NHU cells in vitro in order to determine if all cells have similar progenitor properties or whether a distinct stem cell population may be isolated.
Mechanotransduction in the bladder
Many conditions affect bladder function and have devastating consequences for quality of life. Common conditions include cystitis (painful inflammation of the bladder which is usually caused by infection, but may also occur as a chronic condition with no apparent cause), urinary incontinence (loss of bladder control, which is a particular problem in the elderly) and bladder cancer (the fourth most common cancer). At present many of these conditions are intractable and any progress towards new treatments (including tissue engineering) requires a better understanding of bladder structure and functional relationships. Although the bladder is often thought of as a hollow elastic organ that stores urine, this simplistic representation is far from the truth. The bladder needs to be able to accommodate major changes in intravesicular volume and surface area during filling/voiding cycles, without sustaining any significant rise in pressure which would damage the kidneys. Understanding how this is achieved in the bladder is a challenging multidisciplinary problem to integrate the material and mechanical properties of the bladder with a cell/tissue biology approach to understanding the mechanisms of mechano-sensation and -transduction. The project could be pursued along several single or combined approaches, including investigating the mechanical/biological interface, using a cell culture approach to examine the effects of mechanical stretch on second messenger release and cell response, or developing a computational model of the system incorporating finite element modelling of the mechanical environment with an agent-based model of cell signalling and response.
