ROS, identified as a driver for fibroblast activation, can be counteracted by glucocorticoid in LINC00605-dependent GMD machinery

Fibroblast-to-myofibroblast transformation embodies a central facet of fibroblast activation, evidenced by elevated α-SMA levels and increased extracellular matrix synthesis. While excessive reactive oxygen species (ROS) are traditionally viewed as drivers of oxidative stress-related damage, emerging data implicate ROS in the pathological transformation of certain fibroblast subsets. However, the precise contributions of raised ROS to fibroblast activation remain to be defined. In this study, employing single-cell RNA sequencing and hypertrophic scars as a model of phenotypic transition, we demonstrate that elevated ROS promotes fibroblast transition to the myofibroblast state, marked by excessive proliferation and collagen synthesis. Conversely, ROS inhibition attenuates this phenotypic shift. Notably, glucocorticoids-classically anti-inflammatory agents-were found to suppress ROS generation in hypertrophic scar-derived fibroblasts (HSFBs). This effect is mediated by downregulation of NOXA1, a pivotal ROS-producing gene. Moreover, the glucocorticoid-mediated reduction of NOXA1 expression does not occur via the classical glucocorticoid receptor (GR) pathway but through a novel LINC00605-dependent glucocorticoid receptor-mediated mRNA degradation (GMD) mechanism. Mechanistically, GR binds NOXA1 mRNA, while glucocorticoid-induced upregulation of LINC00605 directly engages the GMD factor YBX1. The LINC00605-YBX1 complex is selectively recruited to NOXA1 mRNA via lncRNA-mRNA interactions, promoting GMD complex assembly and ultimately triggering NOXA1 mRNA decay. Collectively, these findings indicate that elevated ROS-driven fibroblast activation and intercellular phenotypic transitions can be reversed by glucocorticoids through ROS suppression, highlighting ROS-targeted strategies as promising approaches to mitigate hypertrophic scarring.