Award details

Elucidating the mechanisms underpinning direct reprogramming of endothelial cells for use in regenerative medicine

Reference	BB/M003221/1
Principal Investigator / Supervisor	Professor Andriana Margariti
Co-Investigators / Co-Supervisors
Institution	Queen's University of Belfast
Department	Centre for Experimental Medicine
Funding type	Research
Value (£)	383,387
Status	Completed
Type	Research Grant
Start date	31/12/2014
End date	06/03/2018
Duration	38 months

Abstract

Cardiovascular disease is the leading cause of death worldwide and is characterised by endothelial cell (EC) dysfunction. Replacing damaged ECs has been recognised as a potential therapeutic option but identification and availability of appropriate cell types has been a major limitation. Recently, a new paradigm of direct reprogramming strategy; "conversion of one somatic cell type to another through reprogramming" has been devised. We reasoned that, at earlier time points during reprogramming, we could direct the epigenetically activated cells which are induced by the iPS cell factors into lineage specific cell types such as ECs under defined conditions without traversing pluripotency. To this end, we adapted a method to generate partially reprogrammed cells, which did not form tumours in vivo and clearly displayed the potential to differentiate into ECs. However, the efficiency of direct reprogramming is very low and the underlying mechanisms remain unclear. Studying the mechanisms underpinning this process should permit for improvements in reprogramming methods and generate fast and efficient strategies. In this study I will elucidate the mechanisms underpinning direct reprogramming of ECs. In particular, it is hypothesised that the direct reprogramming towards ECs is a two-step approach. Initially, the four reprogramming factors activate EC-Regulatory-Networks, which will respond to specific stimuli such as Vascular Endothelial Growth Factor and Fibroblasts Growth Factor and will allow the induction of EC specific markers. This knowledge will allow us to realise fundamental principles of cell reprogramming and establish homogeneous populations of differentiated cells. Importantly, this work will also establish the potential of reprogrammed ECs to enhance angiogenesis and neovascularisation. Together, these findings may establish the therapeutic potential of reprogrammed ECs which would have transforming consequences for regenerative and personalised medicine.

Summary

Cardiovascular disease is the leading cause of death worldwide and is characterised by the dysfunction of the endothelium, which is the thin layer of cells that lines the interior surface of blood vessels. The cells that form the endothelium are named endothelial cells (ECs). Therefore, replacing damaged ECs has been recognised as a potential therapeutic option for cardiovascular disease but identification and availability of appropriate cell types has been a major limitation. Based on the remarkable recent discovery, human fibroblasts or other somatic cells have the potential to initiate a reprogramming process and become pluripotent. This is a method based on the forced-expression of four reprogramming transcription factors, which are able to transform any differentiate cell back to the pluripotent stage. These cells are named induced pluripotent stem cells and hold a great potential for regenerative medicine. As these cells are pluripotent, they are also able to differentiate towards any cell type within the body and be used for cell therapy. Indeed induced pluripotent stem cells are able to differentiate to ECs and in theory could be a great cell source to treat cardiovascular disease. Although, the use of induced pluripotent stem cells to derive ECs may preserve a great potential for personalised medicine and vascular cell therapy, the main restriction is the risk of these cells to develop tumors as they are in a pluripotent stage. To overcome this limitation, recently, a new paradigm of direct conversion of one differentiated cells to another has been proposed. In this regard, we have asked the question whether it would be possible to bring a differentiated cell type to a transient state where it could be easily directed to another desired cell type like ECs, without reaching pluripotency. To this end, we adapted a method to generate partially-induced pluripotent stem cells by overexpressing the 4 reprogramming factors to human fibroblasts for short periods of time. Importantly, these cells did not form tumours and clearly displayed the potential to differentiate into ECs when they were stimulated with specific growth factors and cultured in appropriate conditions. This new approach is named direct reprogramming and holds an enormous potential for regenerative medicine. However, the efficiency of direct reprogramming is very low because the underlying mechanisms remain totally unclear. Studying the mechanisms underpinning this process should permit for improvements in reprogramming methods and generate fast and efficient direct reprogramming strategies, which could be used in future clinical applications to benefit specific-patients' groups. In this study I will elucidate the mechanisms behind direct reprogramming of ECs in order to establish homogeneous populations of differentiated cells to be used in regenerative medicine to treat vascular disease. In particular, we hypothesise that the direct reprogramming towards ECs is a two-step approach. Initially, the four reprogramming factors activate specific gene regulatory networks related to ECs, which will respond to specific stimuli such as Vascular Endothelial Growth Factor and will allow the induction of EC specific markers (second step). This study will elucidate for the first time the mechanisms of direct reprogramming towards ECs providing novel data which will support that direct reprogramming is a two-step process. This study holds the promise to uncover the underlying mechanisms of direct reprogramming which could be expanded to other cell lineages beyond EC reprogramming. Importantly, this work will also establish the potential of reprogrammed ECs to restore EC function and promote perfusion of ischemic tissue in appropriate research animal models. Together, these findings may establish the therapeutic reality of reprogrammed ECs which would have transforming consequences for regenerative and personalised medicine.

Impact Summary

Academic: The results of this proposed study will be presented at scientific meetings and they will be engaged with academics through publication in the leading high-impact journals in the field. The data will also be presented at annual international and national scientific meetings such as the International Society for Stem Cell Research (ISSCR), American Heart Association and the British Society for Cardiovascular Research, as the applicant is a regular attendee at these scientific conferences. Public: Direct reprogramming is a very interesting and novel approach, which it has an enormous potential for regenerative medicine. We have recently reported for the first time in Proceedings of the National Academy of Sciences USA our success to directly reprogram fibroblasts into endothelial cells. This work has been highlighted in a press release and in the university webpage as cutting-edge research in the field of regenerative medicine. Importantly, this article has been selected by the British Heart Foundation (BHF) for use in an open competition for PhD students to produce an essay based on the significance of this work in cardiovascular disease. A Commentary on Cutting Edge Science entitled as "Therapeutic transdifferentiation: a novel approach for vascular disease" has also been published in Circulation Research based on our work. Therefore, it is anticipated that the proposed study will have a high public profile since it can demonstrate the potential to provide benefits to patients in the long-term so it is expected to generate substantial interest. An outline of this work will be posted on the Queen's University Belfast (QUB) web pages. Information will also be provided to local charities or patient groups detailing its contribution to improve understanding and treatment of vascular disease. For example, the Centre for Centre for Experimental Medicine stem cell group recently participated in the Eurostem cell initiative, whereby debates are brought to schoolgroups across Europe, including Northern Ireland and the UK (http://www.eurostemcell.org/story/who-what-where-when-why-stem-cells-w5-belfast). All of these engagements will be preserved in line with the public relations guidelines of QUB communications office and acknowledgement of BBSRC funding. EXPLOITATION AND DISSEMINATION. The impact of this research has the potential to contribute to the broader community by serving to prevent a major cause of morbidity and reduced quality of life. The applicant is actively engaged in presenting her work to the non-scientific community on a number of occasions including to patient groups and charity bodies. Since cardiovascular disease maintains a high profile and our project has the potential to provide benefits for these patients in the long-term, the process of direct reprogramming is a very attractive and novel approach. Thus, it would be expected to generate considerable interest consistent with the clear therapeutic promise of regenerative medicine. We will attempt to target and engage a wide range of stakeholders, including research scientists, clinicians, and cardiovascular support groups. Our previous success in this area is evidenced by selection of our recent publication in Proceedings of the National Academy of Sciences USA by the BHF for a PhD student competition, as detailed above. We will also work closely with the institutional communications office at QUB to stimulate similar events and increase the amount and quality of research-related information available to the public. Schools, young People and other related events: Importantly, a number of opportunities will be created for young people in order to promote their engagement in science, technology, biology and mathematics. A number of summer laboratory projects, sponsored by appropriate organisations, will also be provided, including stem cell forums and debates about stem cells and cell reprogramming and their potential in clinical application.

Committee	Research Committee D (Molecules, cells and industrial biotechnology)
Research Topics	Regenerative Biology, Stem Cells
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

I accept the terms and conditions of use (opens in new window)

export PDF file

back to list new search