Friedman Ryan M, Truong Huy D, Aronson Matthew R, Brown Elizabeth A, Angelozzi Marco, Chen Jeffrey F, Zur Karen B, Lefebvre Véronique, Gottardi Riccardo
Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Otolaryngology, Department of Surgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
Division of Orthopaedics, Department of Surgery, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
Matrix Biol. 2025 May;137:1-11. doi: 10.1016/j.matbio.2025.02.004. Epub 2025 Feb 14.
Vocal fold scarring, the most common cause of poor voice after airway injury, involves the transition of vocal fold fibroblasts to contractile myofibroblasts. Vocal fold myofibroblasts can be characterized by significant extracellular matrix (ECM) secretion and stress fiber formation. Biochemical signals, such as transforming growth factor (TGF)-β1, and biophysical cues, such as matrix stiffening, have been shown to induce the fibroblast-to-myofibroblast transition. To identify key intracellular pathways that may mediate myofibroblast activation, we performed bulk RNA sequencing of human vocal fold fibroblasts treated with or without TGF-β1 and found that genes downstream of myocardin related transcription factor A (MRTF-A) and serum response factor (SRF) were upregulated in TGFβ1-induced myofibroblasts. We then show that both TGF-β1 and ECM stiffening induce MRTF-A and SRF nuclear translocation during vocal fold myofibroblast activation. Inhibition of MRTF-A via CCG-257,081 reduced pro-fibrotic gene expression, the percentage of α-smooth muscle actin (α-SMA)-positive fibroblasts, and cell contractility in vitro. In a murine model of vocal fold scarring, MRTF-A inhibition reduced vocal fold scarring severity, evidenced by reduced epithelial thickening, decreased glycosaminoglycan content, and collagen deposition, and decreased expression of ACTA2. Our study suggests that the MRTF-A/SRF pathway regulates vocal fold myofibroblast activation, and that inhibition of MRTF-A has a protective effect against vocal fold scarring in mice.
声带瘢痕化是气道损伤后声音嘶哑的最常见原因，它涉及声带成纤维细胞向收缩性肌成纤维细胞的转变。声带肌成纤维细胞的特征是大量分泌细胞外基质（ECM）并形成应力纤维。生化信号，如转化生长因子（TGF）-β1，以及生物物理线索，如基质硬化，已被证明可诱导成纤维细胞向肌成纤维细胞的转变。为了确定可能介导肌成纤维细胞活化的关键细胞内信号通路，我们对用或不用TGF-β1处理的人声带成纤维细胞进行了批量RNA测序，发现心肌素相关转录因子A（MRTF-A）和血清反应因子（SRF）下游的基因在TGFβ1诱导的肌成纤维细胞中上调。然后我们表明，在声带肌成纤维细胞活化过程中，TGF-β1和ECM硬化都诱导MRTF-A和SRF核转位。通过CCG-257,081抑制MRTF-A可降低促纤维化基因表达、α-平滑肌肌动蛋白（α-SMA）阳性成纤维细胞的百分比以及体外细胞收缩性。在声带瘢痕化的小鼠模型中，MRTF-A抑制降低了声带瘢痕化的严重程度，表现为上皮增厚减轻、糖胺聚糖含量降低、胶原蛋白沉积减少以及ACTA2表达降低。我们的研究表明，MRTF-A/SRF通路调节声带肌成纤维细胞的活化，并且抑制MRTF-A对小鼠声带瘢痕化具有保护作用。
