Novel Approaches to Enhance Animal Embryonic Stem Cell Research (STELLAR)
Project Leader
Prof. Cesare Galli, Italy
Principal Investigators
Dr. Paolo Vezzoni, Italy
Prof. Pasqualino Loi, Italy
Dr. Josef Fulka, Czech Republic
Prof. Keith H. S. Campbell, UK
Dr. Robert Feil, France
The establishment of human ES cells has given tremendous input to the concept of stem cell-based therapies and the parallel development of somatic nuclear transfer has opened the perspective of autologous stem cell therapy in human medicine.
Somatic cell nuclear transfer is currently the only procedure that allows the complete reprogramming of the genome of a differentiated cell into an embryonic stem cells (nuclear transfer stem cells, NTSC). Enucleated matured oocytes are commonly used, however other stages of oocyte maturation or oocytes from a species different from the nuclear donor offer opportunities to overcome biological and / or practical limitations.
Nuclear donor pre-treatment with drugs acting on chromatin structure or exposure to cell extract may provide an ex ovo reprogramming strategy. Understanding the events taking place during this nuclear-cytoplasmic interaction will provide the basis for genome reprogramming in vitro of somatic cells and therefore the creation of immunological compatible cells for cell replacement therapies, combining the potential of embryonic stem cell technology to the theoretical generation of any given somatic tissue. However, evidence for epigenetic defects in cloned embryos and lack of cell transplantation models are raising concerns on the long-term safety of such applications. For all of these reasons, there is an urgent need to develop strategies to improve the fidelity of reprogramming and to investigate new routes for stem cell derivation directly from somatic cells including interspecies nuclear transfer and in vitro reprogramming (ex-ovo reprogramming). Here we propose a comparative and multidisciplinary approach that uses non human mammals (cattle, sheep, pig and mouse), as model systems for the derivation, molecular and epigenetic characterization and in vitro/in vivo differentiation of NTSC lines. The project is expected to shed light on the basic features of nuclear transfer embryonic stem cells across species responding to the need for new animal models and encouraging comparative approaches.
Regulation of Hematopoietic Stem Cell Self-Renewal in the Embryo (HSC-SR)
Project Leader
Prof. Elaine Dzierzak, the Netherlands
Principal Investigators
Prof. Tariq Enver, UK
Dr. Anna Bigas, Spain
Hematopoietic stem cells (HSC) are robust, self-renewing cells at the base of the extensive blood cell differentiation hierarchy. In the adult, HSC numbers are kept constant through self-renewing cell divisions (one daughter differentiates, one remains a stem cell). At present, the molecular mechanisms involved in the regulation of stem cell fate and division are poorly defined. It is expected that extrinsic signals play a major role in these processes and that these signals are most likely interpreted by pivotal transcription factors that alter the intrinsic gene expression program. Gene targeting studies show GATA-2 as a pivotal HSC transcription factor, with subtle changes in GATA-2 levels profoundly altering HSC fate. Extrinsic regulators of GATA-2 include the well-known adult hematopoietic cytokines SCF and IL-3. While such cytokines have some affect on HSCs, more attractive candidates for extrinsic regulators are the highly conserved Notch and Wnt developmental signaling pathways. These key signaling pathways direct stem cell fate and proliferation in neuronal or intestinal stem cells and there is some evidence for their role in HSCs. Our preliminary data indicate that GATA-2 may be a downstream target of Notch signaling. Hence, we propose to further examine the affects of the Notch and Wnt signaling pathways on HSC functionality throughout ontogeny. Each collaborating internationally competitive laboratory - Dzierzak (NL), Enver (UK) and Bigas (Spain) - studies a unique aspect of HSC biology, while sharing a common interest in GATA-2. Together, we will use novel assays for measuring HSC fate, along with state-of-the art techniques for HSC identification, signal transduction, gene regulation and array screening. Candidate target genes will be tested for their function in HSC self-renewal by RNAi gene expression knockdown. Our resulting knowledge of the extrinsic and intrinsic regulators involved in HSC self-renewal will be exploited so as to facilitate the ex vivo expansion/manipulation of human HSCs for clinical purposes.
Translational stem cell research: from basic biology to regenerative medicine
Project Leader
Prof. Stefan Krauss, Norway
Principal Investigators
Dr. Thorarinn Gudjonsson, Iceland
Dr. Morten Meyer, Denmark
Dr. Juha Partanen, Finland
Dr. Dirk de Rooij, the Netherlands
Dr. Fiona Watt, UK
Associated Partners
Prof. Irma Thesleff, Finland
Prof. Hannu Sariola, Finland
Prof. Ernest Arenas, Sweden
Prof. Patrik Brundin, Sweden
Dr. Jonas Muhr, Sweden
Prof. Jonas Frisen, Sweden
This application involves the joined forces of 13 research groups from 6 countries with common interests and complementary competence in developmental biology, stem cell biology, regenerative medicine and cancer biology. The consortium aims at elucidating the mechanisms that control self-renewal and differentiation of stem cells in their natural environment, the stem cell niche, in 3D cell culture and upon transplantation. A multitude of stem cell systems will be used comparatively, including haematopoetic, neural, breast, tooth epithelial, spermatogonial, skin, hair and embryonic stem cell populations. Work will be carried out with mouse, rat, chicken, bovine, monkey and human systems (however not using human embryonic stem cells). New methods including advanced in vitro cultures of cells and tissues as well as genetic manipulations will be developed for our studies. This multidisciplinary effort will be necessary for a better understanding of the basic biology of stem cells as a prerequisite for their therapeutic use in the future. Potential parallels between stem cells and cancer stem cells will be investigated and we project an impact of our proposed research on understanding tumorigenesis and therapeutic strategies in tumor biology. Finally, the gained knowledge on pathways involved in stem cell maintenance and differentiation will be used to create defined reporter cell lines for drug screening programs. Biobanking for high purity reference stem cell populations, and defined stem cell populations carrying reporter genes for drug assays will be established. Here, we will seek collaboration with other stem cell forums such as the International stem cell forum (hosted by MRC, UK).
Within these objectives an integrated network will be established to create a critical mass and a stable framework for scientific interaction. The coordinated thematic platforms will allow us to build knowledge that can be translated into stem cell therapeutics. Research training will be supported within the EuroSTELLS network by stimulating mobility and offering possibilities for the graduate and postdoctoral students to visit other participating labs, and by organizing training courses in different formats in various fields of stem cell research.
This ESF application will provide the fundament for a stable and long term supranational structure in stem cell research and regenerative medicine.
