Mechanotransduction unifies healthy nondiabetic wound healing over time by promoting a Cd14+/C1qa+ fibroblast subpopulation

Diabetes is a major growing public health concern, but the impact on cellular impairments in chronic wounds remains incompletely understood. Fibroblasts, key players in all phases of wound healing, are particularly responsive to mechanotransduction. In this study, we characterize fibroblast heterogeneity in genetically induced and pathophysiologic diabetic murine wounding models across all wound healing phases. Full-thickness excisional wounds were created on the dorsum of C57BL/6 nondiabetic wild-type mice (denoted as N-DB); wild-type mice fed a high-fat diet to create pathophysiologic diabetes (denoted as P-DB); and leptin-receptor-deficient mice, a genetically induced diabetic model (denoted as G-DB). Tissue was submitted for single-cell RNA sequencing at postoperative days 0, 2, 7, and 30. Both G-DB and P-DB significantly impaired wound healing compared with N-DB. N-DB expressed distinct myeloid-like Cd14+/C1qa+ angiogenic fibroblasts at postoperative days 2 and 7. Mechanotransduction pathways, focal adhesion kinase (FAK) and mitogen-activated protein kinase (MAPK), were consistently upregulated in N-DB fibroblasts and depleted in both diabetic models. G-DB upregulated WNT-activated Dpp4+ fibrotic fibroblasts at postoperative day 7 compared with N-DB. Thus, mechanotransduction pathways are present in physiologically healing fibroblasts and are selectively depleted in both pathophysiologic and genetically induced diabetes. In genetically induced diabetes, overactivation of canonical and noncanonical WNT pathways overwhelms cells and impairs healing processes. Transcriptomic insights into these mechanotransducive perturbations may lead to new therapies for diabetic wound repair.