2001 Route 28 Summit Participants and Proposals
The Id of Stem Cells
Redefining stem cell plasticity and identity for CNS repair
The 2001 Chalenges
Chose an experimental model within the area assigned to your question and develop a repair strategy using stem or progenitor cells.
1. Chose a model from the area of spinal cord trauma.
Groups 1, 2, 3 (Green)
Devise a strategy that allows to generalize results and to transfer knowledge from one disease model to another. Are there tests for aspects of "stemness" that allow one to determine how suitable (certain types of) stem cells are for a given model? How specific has a model to be in order to be successful? Is it better to be specialized or generalized? Is there a way this question can become integral part of the experimental strategy?
2. Chose a model from the area of Parkinson's disease, Alzheimer's disease, or Huntington's disease.
Groups 4, 5, 6 (Yellow Dot)
How can safety standards for stem cell applications in a specific disease model be developed? What are the safety issues and how can they be covered? Is it possible to explore in a preclinical context to assess long-term outcome, cell growth, cell numbers and prevention of tumor formation? How can the question of safety be used to stimulate the experimental work beyond limiting it?
3. Chose a model from the area of ischemic damage to the brain.
Groups 7, 8, 9 (Blue dot)
The vast potential of stem cells could imply that cells are doing to much of good thing. Devise a strategy to limit your success in a stem-cell based therapy in order to avoid side effects! Which aspects of "too much of good thing" are there? Are there general criteria to define such issues? How can they be incorporated into experimental paradigms?
|Group 1||Group 4||Group 7|
|Biernaskie, Jeff||Groszer, Matthias||Fowler, Christie|
|Boettcher, Rika||Hamilton, Heather||Masino, Amanda M.|
|Canoll, Peter||Lu, Paul||Priller, Josef|
|Emsley, Jason G.||McNamee, Dawn Michelle||Santarelli, Luca|
|Strauss, Ulf||Mellot, Tiffany||Shear, Deborah A.|
|Chung, Kwan-Ho||Guhda, Udayan||Acar, Melih|
|Falk, Anna||Hoehn, Benjamin Douglass||Belkadi, Abdelmadjid|
|Oakland, Kristin A.||Irvin, Dwain||Gotts, Jeffrey E.|
|Soen, Yoav||Johansson, Clas B.||Han, Steven S. W.|
|Sun, Yi||Lichtenwalner, Robin||Schaefer, Alisa|
|Group 3||Group 6||Group 9|
|Haas, Stefan||Carlen, Marie||Au, Edmund|
|Marshall, Christine A. G.||Klucken, Jochen||Erickson, Rebecca|
|Messina, Darin J.||Romero-Ramos, Marina||Momma, Stefan|
|Mitchell, Ellen Siobhan||Van Kampen, Jakalina M.||Seaberg, Raewyn|
|Seri, Bettina||Visnyei, Koppany||Taylor, Merritt|
|Sun, Dong||Xu, Jie||Wachs, Frank Peter|
Proposal Review Committee
Abstracts from the Winning Groups:
Group 1: Jeff Biernaskie, Rika Boettcher, Peter Canoll, Jason Emsley, Ulf Strauss, Tamily Weissman
The Id of Astrocytes?: Radial Glia for Axonal Regeneration.
Spinal cord injury affects thousands of individuals and is often resistant to treatment options aimed at regeneration. The embryonic mammalian spinal cord and the adult urodele salamander, however, possess permissive environments for axonal regeneration. Such permissiveness may derive from the presence of radial glial cells (RGCs) which secrete ECM molecules and provide a crucial scaffold during nerve fiber migration. RGCs then give rise to SVZ cells and astrocytes, which themselves may de-differentiate to a more primitive state. The transmembrane protein Notch is expressed in RGCs and regulates the transition between radial glial and astrocytic states. Our long-term goal is to harness the gliogenic properties of the neural stem cell lineage to return the in vivo spinal cord environment to a state which is favorable to axonal regeneration. To meet this goal we have two aims.
Aim #1 is to demonstrate in vitro that adult isolated astrocytes can be converted to an immature or radial glial phenotype, and that these cells, or radial glial cells isolated directly from the embryonic CNS, can promote axonal outgrowth in culture.
Aim #2 is to induce endogenous spinal cord astrocytes to take on immature or radial glia-like properties in vivo and demonstrate that they, or exogenously introduced embryonic radial glial cells, are capable of reducing injury and promoting axonal regeneration in a murine contusion model of spinal cord injury. These parallel in vitro and in vivo studies will enhance our understanding of neural stem cell gliogenesis in general, and provide potential implications for clinical neural repair strategies.
Group 6: Marie Carlen, Jochen Klucken, Marina Romero-Ramos, Jakalina M.Van Kampen, Koppany Visnyei, Jie Xu.
Safety issue concerns are currently the main limitating factors to consider in treatment of neurodegenerative disease using cell transplant therapies. In the present proposal we will address this issue in the treatment of Alzheimer’s Disease (AD). Insufficient neuroregeneration, hyporeactive immune-response and the diffuse distribution of amyloid accumulations (plaques) are regarded as the main cause of the chronic neurodegeneration in AD. Therapeutic approaches performed so far are limited by safety problems due to the technical design of the therapeutic strategy (surgical limitation, non controlable drug release and non desired systemic effects).
To address these problems we will design genetically modified autologous T-cells that are tracked to the amyloid plaque enriched area (improvement of immunoresponse), locally release NGF (neuroregeneration) and/or amyloid antisense molecules (prevention of neurodegeneration), both in an autoregulated manner. To further improve the safety transplanted T-cells contain a suicide gene that can be induced by drug treatment. In the first part of our project the T-cells will be generated, genetically modified and tested in vitro. Secondly, in vivo assessment of functional active T-cells in the CNS after systemic transplantation (intravenous injection) will be confirmed. Thirdly, safety issues and efficacy will be addressed by using different combinations of T-cell concentrations and gene expression levels in a long term approach. After showing the improvement of safety efficacy these therapeutic system can be easily transferred to other chronic degenerative diseases by using primed T-cells against other proteins of interest (e.g. alpha-synuclein in Parkinson´s disease) and using other growth factors or therapeutic molecules.
Group 9: Edmund Au, Rebecca Erickson, Stefan Momma, Raewyn Seaberg, Merritt Taylor, Frank-Peter Wachs
Genetically engineered stem cells deliver trophic factors to site of cerebral ischemia: A general strategy for minimizing secondary damage
Stroke results in necrotic and apoptotic cell death through a variety of cellular mechanisms. Although there is a high degree of cell loss in the ischemic core itself there is a greater therapeutic opportunity for rescuing cells from secondary damage in the surrounding penumbra. Many secreted factors (including IGF-1, BDNF and bFGF) have been implicated in minimizing the secondary damage from stroke. However, the key common problem with delivering these factors to the site of injury has been the inefficient passage of these agents across the blood brain barrier. We have devised a strategy to overcome this problem by utilizing a bone marrow stem cell based delivery system that exploits the documented ability of these cells to localize to the lesion site.
We have designed a lentiviral shuttle system to introduce transgenes into rat ROSA26 bone marrow cells such that they overexpress a secretable factor in the region of secondary damage. In consideration of the reported poor translation of experimental rodent model systems to human clinical trials, we have chosen aged rats (1.5 – 2 years) in an effort to more accurately reflect stroke pathology. Within the context of an MCA occlusion model we plan to assess histological and functional outcome of a transplant of these genetically modified bone marrow cells. This will be accomplished using Micro-PET, immunohistochemistry using caspase-3/9 and GFAP (for glial scarring) to assess histological outcome. The modified neurological severity score and the Rotor rod test will proved measure of behavioural and functional change. We propose a novel treatment strategy that combines the ability of bone marrow stem cells to localize to the lesion site with an efficient regulatable neurotrophic secreting system. This system is amenable to the delivery of various neuroprotective or trophic factors and may prove valuable for the treatment of stroke as well as other neurological injuries.