Tools and Technologies I
Statement of Benefit to California:
The proposal is based on an interdisciplinary approach to development of defined, robust and scalable culture conditions using synthetic extracellular matrices for undifferentiated hESC expansion. The team is composed of domain experts in cell biology, stem cell cultivation, peptide chemistry and materials science. The group has identified receptors that are mediators of adhesion and survival of hESC. They propose to build on their preliminary data by developing and screening peptide-hydrogels for ability to support adhesion, survival, proliferation and differentiation of cultured hESC. Inkjet printing will be used to array candidate peptides and combinations of peptides for high throughput studies. The candidate peptide-hydrogels identified in the screening assays will be more fully characterized for effects on phenotype and karyotypic stability. The most promising candidate peptide-hydrogels will be further optimized by quantitative examination of mechanical properties that affect particular stem cell outcomes. The proposal addresses the current bottleneck in expanding hESC to numbers and quality sufficient for clinical application (master banks). Current state of the art methods to expand hESC rely on Matrigel as a substrate for cell attachment and trophic support, and many media commonly used in hESC cultivation contain animal products. By focusing on the hESC-extracellular matrix interactions in a systematic way, the proposed work could have enormous impact on methods to control growth and differentiation of hESC to clinically needed numbers. Preliminary data provide solid support for the underlying rationale for the high throughput screening of biomimetic matrices as proposed in the application. The research design follows a systematic and logical approach, though reviewers were not completely sure of the numbers and combinatorics involved in the peptide screening, and exactly how the candidate peptides will be prioritized for further study. Reviewers also appreciated the discussion of potential limitations of the experimental approaches, and alternative strategies. One of the reviewers advised that one of the proposed media components did not fit the goal of examining completely xeno-free methods of hESC expansion since it contains animal-derived product. Since considerable organizational skill is required to coordinate a multidisciplinary team, reviewers applauded the 34% effort of the principal investigator, who is well suited to lead the team of researchers. Each team member is a recognized, respected leader in their particular area of expertise. Thus, with each contributing critical intellectual viewpoints, the lower level of effort of other investigators on the proposal, one of whom appears to be fully committed with other projects, was of some concern. Nonetheless, as a team, this group is exceptionally strong for these kinds of studies. Overall, the application was received enthusiastically for the multidisciplinary approach to an important bottleneck to translation. Though reviewers generally wanted more details of experimental design, they were comfortable that the logical progression of experiments would be feasible and lead to interesting results in the hands of the strong team. Thus potential impact of the work is high.