Configuration of Microprinted Stem Cell Colonies in Heterocellular Niches Regulates Neural Differentiation

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PI: Hossein TavanaProposal ID 1264562Intellectual merit: Stem cells hold a great promise for replacing damaged cells and recovering lost tissue function in patients. Realizing this potential requires the ability to engineer well-defined microenvironments and determine the factors that induce differentiation of stem cells toward specific lineages. This proposal stems from PI's recent works in which it was found that size and interspacing of stem cell colonies in heterocellular stem cell-support cell microenvironments synergistically regulate neural differentiation phenotypes. A major challenge to investigating this phenomenon is the difficulty of creating stem cell colonies of defined size and interspacing directly on a support cell layer. The proposed work will tackle this problem using a new high throughput cell printing microtechnology that enables spatial and temporal control over direct and contact-free positioning of stem cells on support cells. The central hypothesis of the proposed work is that size and spatial organization of stem cell colonies creates gradients of endogenous differentiation-inducing signaling molecules that regulate neural differentiation efficiency. This hypothesis will be tested by engineering the size and interspacing of colonies and thus, systematically manipulating signaling thresholds of cell-secreted endogenous factors. The main objectives are to gain a mechanistic understanding of molecular events that govern this event and propose an approach for enhanced neural differentiation of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). This will be a marked improvement for iPSCs that differentiate with low efficiency in traditional cultures. Success of this proposal will be a step towards realizing transition of stem cell-generated neural cells for treatment of neurodegenerative diseases. This project is transformative as the methodology developed here will be broadly applicable to high throughput screening of fate commitment of stem cells to various lineages in homo- and hetero-cellular niches. The ease of implementing this microtechnology, which only requires inexpensive materials and off-the-shelf equipment, makes it fully accessible to the research community. Broader impact: Developing new cell replacement therapy approaches based on the use of embryonic and induced pluripotent stem cells will have significant public health benefits for treating a wide range of disorders including neurodegenerative diseases that currently lack effective treatment. The proposed microtechnological approach to engineering stem cell niches will identify specific factors that enhance differentiation to neural cells beyond that currently achievable, and therefore will have significant societal impact. The approach to niche engineering will also broadly benefit the research community by offering a useful technology to investigate stem cell differentiation to various cell types in heterocellular niches with long-term impact in tissue repair and regenerative medicine. In addition to the potential medical impacts, the proposed project will improve undergraduate STEM education through several mechanisms. First, undergraduates will be integral to the project, performing, analyzing, and presenting research. It is the PIs' experience that undergraduate students, including women and minorities, who perform research continue on into STEM graduate fields (35/51 undergraduates performing research were females or underrepresented minorities and 22/32 who have graduated continue on to graduate school in STEM fields (primarily BME)). Second, this work will be integrated several aspects of a sophomore level undergraduate computing course. Students will be exposed to the fundamental equations for modeling diffusion as well as an explanation of the problem. They will then investigate solutions for the model in the class using MATLAB®. Finally, this project will increase participation of women and underrepresented minorities in STEM by development of a module for middle and high school students in summer camps at The University of Akron. This module will allow the students to work with the postdoctoral fellow and the graduate student, learn basics of easy-to-use microtechnology, and design and create a print of cells. Therefore, these students will be exposed to advanced technology and research in biomedical engineering.