Macrophage-mediated extracellular matrix remodeling and myofibroblast activation pathway

The macrophage-mediated extracellular matrix (ECM) remodeling and myofibroblast activation pathway is a critical signaling axis involved in tissue repair and the pathogenesis of chronic fibrosis (Wynn & Barron, 2010, Nature). In response to injury, M2-polarized macrophages secrete pro-fibrotic cytokines such as Transforming Growth Factor-beta 1 (TGF-beta1) and Platelet-Derived Growth Factor (PDGF) (Buechler et al., 2021, Nature Communications). These macrophages also release Matrix Metalloproteinases (MMPs) that degrade the basement membrane and ECM, facilitating the migration of fibroblasts and the release of bound growth factors (Giannandrea & Parks, 2014, Reviews in Physiology, Biochemistry and Pharmacology). The resulting signaling environment triggers the differentiation of resident fibroblasts into contractile myofibroblasts, a process marked by the expression of alpha-smooth muscle actin (alpha-SMA) (Meng et al., 2016, Nature Reviews Nephrology). Myofibroblasts are the primary effectors of fibrosis, producing excessive amounts of collagen and other matrix proteins that lead to organ scarring and functional impairment. This pathway is a major driver of diseases such as idiopathic pulmonary fibrosis, liver cirrhosis, and systemic sclerosis. Therapeutic strategies targeting this pathway include the use of tyrosine kinase inhibitors like Nintedanib and TGF-beta synthesis inhibitors like Pirfenidone (Richeldi et al., 2014, NEJM). Emerging treatments also focus on modulating macrophage polarization or inhibiting specific MMPs to restore homeostatic ECM turnover.

Other names

Macrophage-myofibroblast transition (MMT) pathwayPro-fibrotic macrophage-fibroblast axisMacrophage-driven fibrotic signalingM2 macrophage-mediated myofibroblast activation

Inhibition of TGF-beta signaling, blockade of tyrosine kinase receptors (PDGFR, FGFR, VEGFR), and modulation of macrophage polarization to prevent myofibroblast differentiation and excessive ECM deposition.