Surface Tethered Epidermal Growth Factor Protects Proliferating and Differentiating Multipotential Stromal Cells from FasL-Induced Apoptosis§

Authors

  • Melanie Rodrigues,

    1. Department of Pathology, and Pittsburgh, Pennsylvania 15261, USA
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  • Harry Blair,

    1. Department of Pathology, and Pittsburgh, Pennsylvania 15261, USA
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  • Linda Stockdale,

    1. Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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  • Linda Griffith,

    1. Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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  • Alan Wells

    Corresponding author
    1. Department of Pathology, and Pittsburgh, Pennsylvania 15261, USA
    2. McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
    3. Pittsburgh VA Medical Center, Pittsburgh, Pennsylvania 15206, USA
    • S713 Scaife Hall, 3550 Terrace Street, Pittsburgh, Pennsylvania 15261, USA
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    • Telephone: 12-647-7813; Fax: 412-647-8567


  • Author contributions: M.R.: conception and design, performed research, data analysis and interpretation, and wrote manuscript; H.B.: data analysis and image processing; L.S.: prepared tEGF surfaces; L.G.: conception and design, data interpretation, and financial support; A.W.: conception and design, data interpretation, edited manuscript, and financial support.

  • Disclosure of potential conflicts of interest is found at the end of this article.

  • §

    First published online in STEM CELLSEXPRESS September 4, 2012.

Abstract

Multipotential stromal cells or mesenchymal stem cells (MSCs) have been proposed as aids in regenerating bone and adipose tissues, as these cells form osteoblasts and adipocytes. A major obstacle to this use of MSC is the initial loss of cells postimplantation. This cell death in part is due to ubiquitous nonspecific inflammatory cytokines such as FasL generated in the implant site. Our group previously found that soluble epidermal growth factor (sEGF) promotes MSC expansion. Furthermore, tethering EGF (tEGF) onto a two-dimensional surface altered MSC responses, by restricting epidermal growth factor receptor (EGFR) to the cell surface, causing sustained activation of EGFR, and promoting survival from FasL-induced death. sEGF by causing internalization of EGFR does not support MSC survival. However, for tEGF to be useful in bone regeneration, it needs to allow for MSC differentiation into osteoblasts while also protecting emerging osteoblasts from apoptosis. tEGF did not block induced differentiation of MSCs into osteoblasts, or adipocytes, a common default MSC-differentiation pathway. MSC-derived preosteoblasts showed increased Fas levels and became more susceptible to FasL-induced death, which tEGF prevented. Differentiating adipocytes underwent a reduction in Fas expression and became resistant to FasL-induced death, with tEGF having no further survival effect. tEGF protected undifferentiated MSC from combined insults of FasL, serum deprivation, and physiologic hypoxia. Additionally, tEGF was dominant in the face of sEGF to protect MSC from FasL-induced death. Our results suggest that MSCs and differentiating osteoblasts need protective signals to survive in the inflammatory wound milieu and that tEGF can serve this function. Stem Cells2013;31:104–116

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