Poster BB14 - Extracellular Matrix Composition Is Modulated By Intercellular Communication Between Fibroblasts and Adipocyte Lineage Cells

Introduction: Adipose tissues can actively participate in wound healing and are used as autologous fat micrografts to improve the appearance and condition of scar tissues. Adipose tissue is composed of many cell types, including adipocyte-derived stem cells (ADSCs), pre-adipocytes, and adipocytes (i.e., adipocyte lineage cells). Adipocyte lineage cells and fibroblasts contribute to extracellular matrix (ECM) remodeling and wound repair; however, it remains largely unknown which cell-types and underlying biological processes are responsible. We have combined a 3D human adipocyte spheroid culture system with an engineered in vitro system for investigating cutaneous wound healing to better understand how adipocyte lineage cells interact with fibroblasts. We compared the evolution of fibroblast-adipocyte lineage cell spheroid interactions and quantified differences in the ECM proteins they produced using liquid chromatography with tandem mass spectrometry (LC-MS/MS). By understanding how the interactions among these cell types impacts ECM synthesis and remodeling, novel adipose-tissue-based therapeutic approaches can be developed to improve wound healing and reduce scar tissue.

Materials and

Methods: Primary human dermal fibroblasts and immortalized human preadipocytes and adipocytes were formed into 3D spheroids and positioned approximately 1 mm apart on the surface of a 6 mg/mL fibrin gel. Six combinations of spheroid pairs were examined on the gel: (1) fibroblast-fibroblast (FF), (2) fibroblast-pre-adipocyte (FP), (3) pre-adipocyte-pre-adipocyte (PP), (4) preadipocyte-adipocyte (PA), (5) adipocyte-adipocyte (AA), and (6) fibroblast-adipocyte (FA). Time-lapse images were acquired for 7 days using a confocal microscope and an environmentally controlled chamber. LC-MS/MS was also used to quantify and classify matrsome proteins among the six spheroid pairings.

Results, Conclusions, and Discussions: Major differences in the extent and patterns of cell migration and collagen deposition were observed among the spheroid pairings. 13 different collagen alpha-chains were identified, with the most prevalent collagens being either type I or type VI collagen (Fig. 1). More type I collagen was produced in adipocytes/preadipocyte co-cultures with fibroblasts (FA, FP) than in fibroblasts alone (FF). AA synthesized the highest diversity of basement membrane proteins (e.g., COL4A1, LAMA1, NID1, etc.). Co-culturing adipocytes with pre-adipocytes or fibroblasts appeared to inhibit the production of several basement membrane proteins. Our data indicates that cross-communication between fibroblast and adipocyte lineage cells signficantly impacts the composition and amounts of ECM proteins produced. Understanding these interactions and how to control them will facilitate the use of adipose-based strageties to improve wound healing and minimize scar.

Acknowledgements (Optional): Support for this work was provided by the National Institutes of Health, NIGMS R01GM145626 and NIEHS P42 ES013661. Adipose was supplied by the Tissue Procurement Core at the University of Iowa which is supported by an award from NIH (NCI award number P30CA086862) and the University of Iowa Carver College of Medicine.