作为经典良性纤维增生性肿瘤，由于其复杂的病理机制，瘢痕疙瘩仍然是一个重要的治疗挑战。确定转化生长因子β1（TGF-β1）/早期生长反应因子1（EGR1）/NADPH氧化酶4（NOX4）轴在瘢痕纤维化病理机制中的功能作用。通过RNA测序分析瘢痕组织和正常皮肤中的差异表达基因。然后，人皮肤成纤维细胞系以10ng/mL的剂量处理TGF-β1，以刺激TGF-β1/SMAD途径，并使用SB431542阻断该途径。此外，通过转染过表达质粒和小干扰RNA，分别过表达和抑制了EGR1/NOX4。使用DCFH-DA检测内源性活性氧的水平，并通过Western印迹分析评估纤维化相关基因的表达水平。另外，双荧光素酶报告分析验证了EGR1和NOX4之间的靶向关系。在瘢痕组织中，TGF-β1/SMAD信号通路被显著激活以促进真皮纤维化。瘢痕纤维细胞中ROS的水平增加。此外，TGF-β1可以通过调节SMAD通路在瘢痕疙瘩中促进EGR1的表达，并促进瘢痕纤维细胞的纤维化表型。EGR1可以通过靶向NOX4调节ROS的产生。此外，NOX4来源的ROS可以促进瘢痕纤维细胞的纤维状表型，并在瘢痕纤维化中发挥重要作用。我们的发现为瘢痕纤维化中的TGF-β1 / EGR1/NOX4通路机制提供了新的见解，而TGF-β1 / EGR1/NOX4轴可能作为瘢痕疙瘩的潜在治疗靶点。版权所有©2022作者。由Elsevier B.V.出版。保留所有权利。

As classic benign fibroproliferative tumors, keloids remain a major therapeutic challenge due to their complex pathological mechanisms.To determine the functional role of transforming growth factor β1 (TGF-β1)/early growth response factor-1 (EGR1)/NADPH oxidases 4 (NOX4) axis in the pathogenesis of keloid fibrosis.Differentially expressed genes in keloid tissues and normal skins were analyzed by RNA sequencing. Then, the human skin fibroblast cell line was treated with TGF-β1 at a dose of 10 ng/mL in order to stimulate the TGF-β1/SMAD pathway and the pathway was blocked using the SB431542. Furthermore, EGR1/NOX4 was over-expressed and inhibited by transfecting overexpression plasmids and small interfering RNAs, respectively. The levels of intracellular reactive oxygen species were measured using the DCFH-DA assay, and the expression levels of fibrosis-related genes were assessed by Western blot analysis. Alternately, dual-luciferase reporter analysis verified the targeting relationship between EGR1 and NOX4.The TGF-β1/SMAD signaling pathway was significantly activated in keloid tissues to promote dermal fibrosis. The level of ROS was increased in keloid fibroblasts. Moreover, TGF-β1 could facilitate the expression of EGR1 through regulating the SMAD pathway in keloids and promoting the fibrotic phenotype of keloid fibroblasts. EGR1 could regulate the production of ROS by targeting NOX4. Furthermore, NOX4-derived ROS could promote fibrotic-like phenotype of keloid fibroblasts and play an important role in keloid fibrosis.Our findings provide new insights into the mechanisms of the TGF-β1/EGR1/NOX4 pathway in keloid fibrosis, and the TGF-β1/EGR1/NOX4 axis may serve as a potential therapeutic target for keloids.Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.