New Faculty II
$2 994 328
Statement of Benefit to California:
The goal of the proposed research is to understand the development and differentiation of choroid plexus epithelium (CPe), a cell type that has received little attention in stem cell biology. Though primary diseases of the choroid plexus are rare, understanding choroid plexus development is important for therapeutic manipulation of the blood-cerebrospinal fluid barrier (CSF), secreted products from choroid plexus are likely important in general for central nervous system diseases, and the proposed work is potentially important for understanding the normal physiologic maintenance of CSF integrity. In Aim 1 the applicant will examine the interactive role of growth factors for their ability to promote CPe specification. In Aim 2 the role of a candidate negative regulator of CPe specification will be examined. In Aim 3, the applicant will manipulate the growth factors and the negative regulator to optimize differentiation of CPe from human embryonic stem cells (hESCs). Reviewers were excited about the proposal for its clinical relevance. The applicant’s preliminary data suggesting that the major growth factor chosen for study is indeed a critical instructive factor in choroid plexus development was found to be compelling by the review panel. The preliminary data also support the further investigation of the second growth factor chosen for study in CPe development. The proposal to carry out classical developmental biology studies using mouse embryonic stem cells (mESCs) is a strong component of the plan. The applicant proposes staged work, leaving the hESC work for later in the research timeline, capitalizing on the information obtained from the mouse cell work. Based on this plan of action, the feasibility that the applicant will be able to coax choroid plexus development from hESCs is high. The institutional environment, especially with the chosen mentors for the project, was also considered a major strength of the proposal. Reviewers felt that the learning curve for in the initial studies would be steep, but that the project is novel and worth pursuing. The application presents an elegant approach to understanding development of the parts of the brain. Although the mouse studies were logically outlined, the reviewers thought that insufficient detail was presented in the experimental plans. A weakness of the application was the superficial presentation of the mouse genetics. A large number of crosses were discussed, and so the clarity of the complex plan was not optimally presented. The proposal would have been strengthened by more rigorous presentation of quantitative endpoints particularly for the in vitro studies and better tabulation of all the conditions and genotypes to be tested. Another concern is that the applicant still has to make the reporter system needed to read out choroid plexus development, and this may prove more difficult than acknowledged. The applicant does not state how the reporter system construction will be validated. Reviewers were concerned that the plan of manipulating only three factors to generate choroid plexus development (Aim 3) was somewhat naïve, and that the differentiation might be more difficult that acknowledged in the application. Finally, despite the strong developmental biology background of the applicant, the evidence for strong hESC training was not presented, but reviewers felt that this inexperience was balanced by the support of experienced investigators in the institution. The applicant has been at the institution for 7 years, after a post-doctoral position with a leader in cortical development. The applicant has been an assistant professor since 2004. The applicant has strong developmental biology credentials, and so has exactly the background of people who should be drawn into hESC research. The applicant is productive, and recently had a Science publication, as well as some independent funding. The applicant has already obtained good independent funding – An NIH-funded KO2, a March of Dimes grant and an R21 award from NIH. The institution has assigned adequate space to the PI and this project. The institution has assembled a strong team of stem cell researchers, which form the appropriate intellectual and infrastructure environment for these studies. The commitment to the investigator by the institution is enthusiastic and will help to assure success of the project.