An important class of neurological diseases predominantly affects spinal motor neurons, the neurons that control muscle movement. The most well known of these motor neuronopathies is Amyotrophic Lateral Sclerosis (ALS), commonly referred to as Lou Gehrig’s disease for the famous Yankee first baseman who died of the disease. The first symptoms of ALS are usually increasing difficulty walking or speaking clearly. People with ALS progressively lose their ability to initate and control movements, and may become totally paralyzed during the late stages of the disease. There are no cures or effective treatments for these diseases. Riluzole (Rilutek), the only FDA approved medication for ALS, only modestly slows disease progression. Consequently, ALS is usually fatal within one to five years from onset, with half dying within eighteen months. Although genetic studies have identified many mutations that cause these diseases, it is not understood why these mutations kill motor neurons. This lack of understanding about the root causes of motor neuron diseases currently hinders the development of effective treatments. We seek to study motor neurons carrying these mutations in cell culture dishes to understand how these diseases sicken and kill these cells. To generate these motor neurons, we will use embryonic stem cells. Embryonic stem cells can become any cell in our body, including motor neurons. We have developed a new technology that allows us to quickly replace healthy genes with mutant genes in mouse embryonic stem cells. We will use this technology to insert both normal and disease-associated versions of genes into embryonic stem cells. Study of the healthy and mutant mutant motor neurons derived from these embryonic stem cells will shed light on the ways in which the mutations cause harm. The development of cell based models of human diseases is likely to have additional benefits as well. For example, diseased motor neurons grown in cell culture dishes can be quickly and efficiently screened with potential drugs to discover agents that slow, halt or reverse the cellular damage. It is our hope that these experiments will both deepen our understanding of important neurodegenerative disorders, and lead to new directions for the development of effective therapies.
Over 6,000 Americans are diagnosed each year with motor neuronopathies, about the same as are diagnosed with multiple sclerosis. One form of this illness, ALS, is responsible for about one in every 800 deaths, and cause many lengthy and costly hospital admissions. We propose using stem cells to model these diseases so that we can gain a deeper understanding of their root causes. It is our expectation that this deeper understanding will lead to new and better approaches to the treatment of these disorders. In addition, our technology for developing embryonic stem cell-based models of human diseases is likely to have applications in the biotechnology sector. Although our technology is most applicable for modeling simple dominant genetic diseases, it can be adapted to model recessive and complex disorders. Beyond increasing our understanding of human diseases, these cellular models represent useful screening tools for testing novel pharmacological treatments. Identification and development of these new therapies may support new companies or new products for existing companies. We hope that using stem cells to model neurodegenerative disorders will lead to progress in the fight against these diseases, as well as provide the tools and examples for those in academia and industry who hope to create stem cell models of other clinically important disorders.
This application is based on the use of a newly developed technology to create embryonic stem cell (ESC) models of human motor neuron disorders. The applicant’s lab has developed this new technology that allows them to quickly replace healthy genes with mutant forms in mouse ESCs. They will use this technology to insert both normal and disease-associated versions of genes into mouse ESCs. In Aim 1 the applicant will generate ES cell models of human neuropathies. In Aim 2 the genetic and cell biological bases of neurodegeneration will be explored. In Aim 3 the principal investigator (PI) will define motor neuron interactomes for wild-type and disease-associated proteins. In Aim 4 the PI will validate findings in human ES cell models. If successful, the studies will provide a panel of new biological tools to the broader scientific community engaged in research on motor neuron diseases in humans.
Reviewers were very supportive of this candidate and the research environment. The applicant is an M.D. /Ph.D. with a blue chip academic pedigree, who has been highly productive throughout medical and graduate training. The scientific environment is outstanding, and the institution has a very strong history of supporting its young faculty. The research proposal is original and innovative, and there is a good rationale for selection of disease models and appropriate description of procedures. Although the proposal is more goal-oriented than hypothesis driven, reviewers were comfortable with this and commented that the research will provide biological tools.
The research proposal is very strong and relies upon the use of gene traps to create cellular models of neurodegenerative diseases, most notably those that affect motor neurons of the brain stem and spinal cord. ESC’s will be modified with either healthy or disease genes to study how mutations lead to disease. The use of high throughput screening for these cells is innovative. The strengths of the proposal are that, with the exception of Aims 2 and 4, the applicant presented good preliminary data. In Aim 2, while there are no preliminary data, the range of assays proposed are reasonable and, to a large extent, feasible. Another strong point in this application is the discussion of potential pitfalls and alternative strategies that the applicant presents. Aim 4 (the human ES cell work) lacks preliminary data and it was agreed that the PI does not have adequate expertise yet in this arena. A second weakness is the fact that the research plan presents with an unrealistically broad scope. Given sufficient time, reviewers thought that the newly developed system will allow the applicant to insert human genes into each of 19 neuropathological loci that are represented in the gene traps, which would have been an extremely ambitious plan for the timeframe of this proposal. The applicant recognized this fact and cut down the project size by first modeling just three diseases. Even so the plan is quite ambitious, but reviewers felt that this was the sort of high-risk project that CIRM should fund. They commented that the project will benefit from exceptionally strong collaborations, which increases its feasibility.
The applicant holds both an MD and a PhD, although this is not a physician-scientist application. The applicant’s training has been superb and his/her mentors are most appropriate and impressive. The applicant has multiple last author publications in high ranking journals. The mentoring program is entirely appropriate and in fact, ideal. The applicant has the potential to emerge as a leader in cellular modeling utilizing embryonic stem cells; however, reviewers agreed that it would have been a strong application if the applicant more directly addressed how to integrate technical knowledge on hESC differentiation, as the applicant lacks this expertise.
The institutional commitment is strong. Moreover, the track record of the applicant’s institution for promoting the careers of its junior faculty is exemplary.
In conclusion, although this proposal is more goal oriented than hypothesis driven, reviewers agreed that this is a very strong application and is exactly the kind of proposal this RFA is targeting. The real appeal of this proposal is the candidate and the research environment.