7. Project Summary/Abstract
Adult human skin heals by developing fibrotic scar tissue, which can result in devastating disfigurement, growth
restriction, and permanent functional loss. Despite a plethora of clinical options, no current treatment strategies
successfully prevent or reverse this fibrotic process, and scars and their sequelae cost the United States over
$20 billion every year. Progress towards the development of new therapies has been significantly hindered by a
lack of understanding of the cell populations responsible for scarring and their molecular dynamics. Studies in
recent years have reported that adipocytes in wounds are capable of transitioning into fibroblasts (and vice
versa); however, the extent to which adipocyte-to-fibroblast transition contributes to wound fibrosis (scarring),
and whether this process can be targeted to prevent scarring, remain unknown. In this proposal, we explore for
the first time the role of tissue mechanics in conversion of dermal adipocytes to scarring fibroblasts within the
wound environment. First, employing genetic lineage tracing, we will use histology, immunohistochemistry, and
flow cytometry to study adipocyte-to-fibroblast transition and to interrogate the molecular phenotype of adipocyte
lineage-derived fibroblasts within wounds. Second, we will use a Rainbow mouse model to interrogate clonal
dynamics of adipocyte-to-fibroblast transition in wounds, and will apply an integrated multi-omic analysis, with
single-cell transcriptomic (scRNA-seq) and epigenomic (scATAC-seq), spatial transcriptomic (Visium) and
proteomic (CODEX), and quantitative extracellular matrix (ECM) ultrastructural analyses, in order to robustly
define the molecular drivers and pathways involved in adipocyte-to-fibroblast conversion during scarring. Third,
as our preliminary data strongly support a mechanotransduction mechanism underlying adipocyte-to-fibroblast
transition during wound healing, we will inhibit mechanical signaling in adipocytes using both small molecule and
transgenic approaches in order to block adipocyte-to-fibroblast transition. We will apply a similar multi-omic
analysis to elucidate the molecular dynamics that differentiate wound adipocyte dynamics in the context of intact
versus blocked mechanical signaling and determine how inhibiting mechanically driven adipocyte-to-fibroblast
conversion may reduce fibrosis and yield wound regeneration. Our ultimate translational goal is to develop
therapeutics that target fibrogenic wound cell dynamics to promote regenerative healing. Collectively, the
proposed work will significantly enhance our understanding of the key molecular and cellular determinants of
cutaneous scarring, inform the development of novel anti-scarring therapies, and shed light on the contributions
of adipose tissue to wound fibrosis.
