Controlling Adipocyte-Myofibroblast Interactions to Improve Healing

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PROJECT SUMMARY/ABSTRACT Fibrosis and scarring from injury and disease costs $20 billion annually to treat in the US, and even when treated remains a persistent problem that significantly diminishes quality of life. The use of autologous adipose micrografts used in reconstructive surgeries appears beneficial for reducing scar. Furthermore, intradermal adipocytes have also recently gained attention for their role in the early stages of normal wound healing. The objective of this proposal is to determine how human adipocyte lineage cells impact fibroblast-myofibroblast conversion and extracellular matrix (ECM) remodeling in a healing wound. Our long-term goal is to engineer more effective and improved clinical therapies for wound healing. To achieve this objective, we propose three aims that are designed to unravel the communication between adipose lineage cells and fibroblasts. In Aim 1, we will determine how secreted factors from adipocyte linage cells regulate fibroblast-myofibroblast conversion, phenotype, and ECM remodeling. We hypothesize that adipocyte lineage cells differentially regulate inhibition, induction, and reversal of fibroblast to myofibroblast conversion, which in turn impacts the composition of the ECM produced. We also hypothesize that adipokine-induced myofibroblasts (compared to TGF-β1-induced myofibroblasts) produce distinct ECM that results in less scaring. We will test these hypotheses and identify how one-way communication from adipocyte lineage cells regulates fibroblast-myofibroblast activity using a myofibroblast conversion assay coupled with fractionation, proteomics, computational genomics, and inhibition/add-back assays. In Aim 2 we will determine how adipocyte lineage cells coordinate with fibroblasts to remodel ECM. We hypothesize that reciprocal communication between adipocyte lineage cells and fibroblasts- myofibroblasts impacts wound healing by altering cell activity and the composition of the ECM proteins produced by both fibroblasts and adipocyte lineage cells. We will use our 3D adipose spheroids and our 3D in vitro models to interrogate the interactions between the relevant cell types and the composition and mechanics of the ECM produced. In Aim 3, we will complement the in vitro work of Aims 1 and 2 by determining how transplantation of adipocyte lineage cells alter fibroblast behavior and ECM remodeling in a porcine wound model. We hypothesize that wound bed fibroblasts will differentially respond to adipose-based treatments depending on the cellular composition delivered. We will test this hypothesis by assessing the effect of transplanted adipose stem cells, preadipocytes, or adipocytes on fibroblast/myofibroblast behavior and wound healing. Successful completion of these aims will substantially improve our understanding of adipose-fibroblast interactions that will be critical for the development of more effective and improved clinical therapies for wound healing.