Mechanisms Controlling Lineage and Synaptic Specificity of Human Neurons During Transdifferentiation
Basic Biology III
$1 755 864
Neurodegenerative and psychiatric diseases have a devastating impact on millions of people around the world. It is unethical to study and treat these diseases because neurons cannot be isolated and studied from the brains of living patients. The goal of this proposal is to develop new technologies that can be used for the rapid generation of neurons from non-neuronal cells (for example, skin cells) easily obtained from human patients. We expect that our research will facilitate the translational studies of neurodegenerative and psychiatric diseases and development of new treatments.
Statement of Benefit to California:
Neurodegenerative and psychiatric diseases affect thousands of people in California and have a devastating impact on patients and their family members. Unfortunately, progress in understanding the etiology and treatment of these diseases has been slow. One reason for this is that, unlike many other cell types, neurons cannot be isolated from living patients. This proposal aims to develop new technologies that can be used for the rapid generation of neurons from non-neuronal cells. This research may impact the translational studies of neuronal disease and development of new treatment. Thus, our research may significantly improve the quality of life of Californian residents and positively influence the state economy.
Project Synopsis: This proposal is focused on the development of technology to directly reprogram skin cells into a specific subtype of neuron. This technology could then be applied to generate these cells from specific patient populations and model neurological disease. In order to achieve this goal, the applicant proposes two specific aims: (1) to utilize an approach that builds upon published data and the applicant?s preliminary results to accomplish efficient direct reprogramming of skin cells into a functional neuronal subtype; and (2) to define the molecular profile of these neurons. Significance and Innovation: - The reviewers questioned aspects of the scientific rationale for the proposal, including the fundamental assumption that neurons generated in relative isolation in vitro would be close enough to bona fide neurons to serve as a valid disease model. In addition, the rationale for the methods proposed in Aim 2 as means of understanding differentiation is not well supported. These methods are more likely to reveal ways that reprogrammed neurons are unlike native neurons than to reveal factors mediating differentiation. - This proposal addresses a significant issue confronting the study of human neurological disease: the lack of viable source material from patient populations that could be used to better understand disease mechanism. Feasibility and Experimental Design: - Although the experimental approach is reasonable, the lack of experimental detail led to a number of concerns regarding feasibility. - A major concern was whether the throughput of the assay would be sufficient for the brute force strategy proposed. The assay is still being optimized, and the applicant does not provide sufficient detail about its throughput, the length of the process, or the number of cells required and available. - Alternative plans are not well described. For example, the Principal Investigator (PI) acknowledges that the potential for diverse neuronal phenotypes could complicate the analysis but presents no detailed plan for dealing with this issue. - In Aim 2, the applicant proposes a cell sorting strategy that reviewers cautioned would depend on truly reliable reporters. Preliminary data that reporter positive cells co-stain with endogenous markers and that the number of cells that can be sorted is compatible with subsequent assays would have been appreciated. - The applicant has developed impressive tools to investigate direct reprogramming. Principal Investigator (PI) and Research Team: - The PI is a talented and well-trained molecular neurobiologist, but this application represents a substantial departure from his/her established area of expertise. The PI does not have a publication record involving high throughput screens, deep sequencing, or proteomic analyses. - While the PI was well published as a postdoctoral fellow, he/she has not yet published as a senior author. - The team is formed with two talented investigators. However, the role of one, beyond providing fibroblasts, is unclear. In addition, a collaborator in the development of the assay for Aim 1 is named, but no biographical detail or letter of support is included. Responsiveness to the RFA: - The proposal is minimally responsive to the RFA. While it addresses direct programming, which is in scope, it employs a brute force approach and is not focused on mechanism.