3-D Optical Tracking of Bone Marrow Derived Skin Stem Cells

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5) 0852658 Boppart Skin is our largest organ, serving critical roles in fluid homeostasis, thermoregulation, immune surveillance, and self-healing. Disease and/or the loss of major portions of a human?s skin can be disabling and potentially life threatening, and is a major health problem in the U.S. and throughout the world. Stem cells play a critical role in repairing and regenerating many tissues, including the skin. Elucidating the roles that stem cells play in the skin will therefore have a significant impact on not only our fundamental understanding of stem cell dynamics, but also on our treatment of skin diseases, for replacing skin in medical applications, or in rejuvenating skin in our aging population. Recent advances in optical imaging techniques offer an unprecedented combination of high spatiotemporal imaging resolution that can now be applied to visualizing the complex three-dimensional (3-D) dynamics of skin stem cells within normal skin, and in response to skin injury and skin replacement, such as after grafting engineered skin replacements. The intellectual merit of this proposal is represented for the first time by an advanced optical biomedical imaging approach for elucidating the complex dynamics of skin stem cells in vivo and within engineered skin grafts. The hypothesis of this research is that optical coherence and multi-photon microscopy, in an integrated platform, can uniquely track and quantify the different dynamic 3-D in vivo stem cell behaviors in and around autologous and allogeneic engineered skin grafts. With the recent discovery of the skin stem cell niche located within the bulge region of hair follicles, many questions arise as to the dynamic behavior of these stem cells as they migrate from the bone marrow and into the skin niche, as well as in and out of the niche in response to skin injury and disease. This project therefore has intellectual merit in four areas. First, an advanced integrated microscope capable of simultaneous optical coherence and multi-photon microscopy will be utilized to uniquely visualize the structural and functional relationships of stem cells within in vivo skin. Second, this project investigates and longitudinally images in 3-D the migration patterns and dynamics of skin stem cells. This will provide fundamental insight into the role they play in maintaining the function and health of skin. Third, the effects of skin injury, induced by the placement of an autologous skin graft (skin punch biopsy), will be investigated, providing insight into the stem cell dynamics in the healing response. Fourth, this project will longitudinally image the stem cell and tissue responses in vivo following the grafting of allogeneic engineered skin constructs, contributing significantly to the understanding of how skin stem cells interact with engineered tissue grafts within biological hosts. The development and application of more quantitative imaging techniques to analyze the dynamics at the single-cell or cell-population levels will provide further insight into the ability to understand the role of skin stem cells, and ultimately provide a better approach for the treatment of human pathologies that require skin grafting. Taken together, this project is novel in each of these four areas, and the use of these advanced imaging techniques to carry out these investigations is transformative for the fields of stem cell biology and tissue engineering. Considering the broader scope, the outcome of this project is likely to have a significant and broad impact on both the fundamental and clinical understanding on how stem cells behave dynamically in vivo. This project addresses major challenges in stem cell biology and tissue engineering: how to visualize and track cells and small populations of cells in vivo, in 3-D, and longitudinally over time in highly-scattering engineered and natural tissues. This project will integrate state-of-the-art research with educational elements to advance discovery and promote teaching, training, and learning. Undergraduate students, in addition to graduate students, will complete theses related to this work. These students, as well as post-doctoral fellows and research scientists, will develop lifelong career skills in optics, image processing, cell and tissue culture and biology, and the use of pre-clinical models. Under-represented groups including women and minorities will be targeted for research opportunities, and annual laboratory and campus-wide open-house events will be held for outreach to K-12 and community groups. The results and image databases from this project will be disseminated widely through our educational website, local and national conferences, and leading scientific, engineering, and medical publications.