Targeting pleuro-alveolar junctions reverses lung fibrosis in mice.

Lung fibrosis development utilizes alveolar macrophages, with mechanisms that are incompletely understood. Here, we fate map connective tissue during mouse lung fibrosis and observe disassembly and transfer of connective tissue macromolecules from pleuro-alveolar junctions (PAJs) into deep lung tissue, to activate fibroblasts and fibrosis. Disassembly and transfer of PAJ macromolecules into deep lung tissue occurs by alveolar macrophages, activating cysteine-type proteolysis on pleural mesothelium.

CD201 fascia progenitors choreograph injury repair.

Optimal tissue recovery and organismal survival are achieved by spatiotemporal tuning of tissue inflammation, contraction and scar formation. Here we identify a multipotent fibroblast progenitor marked by CD201 expression in the fascia, the deepest connective tissue layer of the skin. Using skin injury models in mice, single-cell transcriptomics and genetic lineage tracing, ablation and gene deletion models, we demonstrate that CD201 progenitors control the pace of wound healing by generating multiple specialized cell types, from proinflammatory fibroblasts to myofibroblasts, in a spatiotemporally tuned sequence.

Visualizing Scar Development Using SCAD Assay - An Ex-situ Skin Scarring Assay.

The mammalian global response to sealing deep tissue wounds is through scar formation and tissue contraction, mediated by specialized fascia fibroblasts. Despite the clinical significance of scar formation and impaired wound healing, our understanding of fascia fibroblast dynamics in wound healing is cursory due to the lack of relevant assays that enable direct visualization of fibroblast choreography and dynamics in complex environments such as in skin wounds. This paper presents a protocol to generate ex- situ skin scars using SCAD or "SCar-like tissue in A Dish" that emulate the complex environment of skin wounds.