Tuning macrophage phenotype to mitigate skeletal muscle fibrosis

DM Stepien, C Hwang, S Marini, CA Pagani… - The Journal of …, 2020 - journals.aai.org
DM Stepien, C Hwang, S Marini, CA Pagani, M Sorkin, ND Visser, AK Huber, NJ Edwards…
The Journal of Immunology, 2020journals.aai.org
Myeloid cells are critical to the development of fibrosis following muscle injury; however, the
mechanism of their role in fibrosis formation remains unclear. In this study, we demonstrate
that myeloid cell–derived TGF-β1 signaling is increased in a profibrotic ischemia reperfusion
and cardiotoxin muscle injury model. We found that myeloid-specific deletion of Tgfb1
abrogates the fibrotic response in this injury model and reduces fibro/adipogenic progenitor
cell proliferation while simultaneously enhancing muscle regeneration, which is abrogated …
Abstract
Myeloid cells are critical to the development of fibrosis following muscle injury; however, the mechanism of their role in fibrosis formation remains unclear. In this study, we demonstrate that myeloid cell–derived TGF-β1 signaling is increased in a profibrotic ischemia reperfusion and cardiotoxin muscle injury model. We found that myeloid-specific deletion of Tgfb1 abrogates the fibrotic response in this injury model and reduces fibro/adipogenic progenitor cell proliferation while simultaneously enhancing muscle regeneration, which is abrogated by adaptive transfer of normal macrophages. Similarly, a murine TGFBRII-Fc ligand trap administered after injury significantly reduced muscle fibrosis and improved muscle regeneration. This study ultimately demonstrates that infiltrating myeloid cell TGF-β1 is responsible for the development of traumatic muscle fibrosis, and its blockade offers a promising therapeutic target for preventing muscle fibrosis after ischemic injury.
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