CAREER: Engineering Three-dimensional Stem Cell Niche with Independently Tunable Biochemical and Mechanical Properties

Stanford University, Stanford CA

Investigators

Abstract

1351289 Yang The overall goal of this project is to develop a novel stem cell niche with biochemical and mechanical properties, which can be tuned independently; and to use this niche to elucidate how signals influence stem cell fate in three dimensions using high-throughput strategies. Intellectual merit Stem cells have the potential to revolutionize medical therapies for a number of diseases. However, directing stem cell fate so that they maintain pluripotency or mutlipotency, or they commit to a certain differentiation lineage, is a critical problem in tissue engineering and regenerative medicine. Although there is ample evidence that stem cells respond to both biochemical and mechanical cues, understanding how the totality of signals in a given environment directs cell fate remains a largely unanswered question, especially in three dimensions (3D). Recent studies from the PI's laboratory indicate that biochemical and mechanical cues interact in a non-intuitive manner to regulate stem cell fate, which cannot be predicted from stem cell responses to individual type of niche cues. The proposed studies are designed to advance the understanding of stem cell-niche interactions by pursuing the following research objectives: Objective 1. Synthesize degradable polymers as biochemical and mechanical "building blocks" of stem cell niche that can crosslink simultaneously and independently to form an interpenetrating network. Objective 2. Develop biomimetic hydrogel microarrays with independently tunable niche properties for encapsulating cells in 3D. Objective 3. Examine the effects of interactive niche signaling on stem cell differentiation in 3D combinatorial hydrogel microarrays in a high-throughput manner. The systematic and combined approach implemented by the PI has a high intellectual merit. Additionally, the proposed studies carry multiple innovative features including the development of interpenetrating network hydrogels with independent control of biochemical and mechanical cues; AFM and FRET-based assays for high-throughput characterization of hydrogel stiffness and degradation; and novel microfabrication platforms and high-throughput screening assays for rapid monitoring of stem cell fate in 3D. Broader Impacts The proposed development of biomimetic hydrogel microarrays with independently tunable cues is expected to comprise a powerful tool to advance the fundamental understanding of stem cell-niche interactions in 3D, thus addressing a critical problem in stem cell biology and tissue engineering. The outcomes of the proposed research may greatly accelerate stem cell-based therapies by rapidly identifying optimal cues to direct stem cells into maintaining pluripotency or differentiating into functional mature cells. Ongoing and new educational plans target students from kindergarten to undergraduates. An outreach program for local elementary school K-G1 students, called "The Magic of Repairing Human Body," will be developed. The PI will also develop a one-week summer camp for high school students on "Tissue Engineering Fiesta, which will include interactive lectures, journal clubs and hands-on activities and will be geared towards high school students from underprivileged and minority background in the San Francisco Bay Area. Overall, the PI addresses a challenging problem with broader implications and has demonstrated commitment towards educational and outreach activities with local schools with diverse student populations.