Ferroptosis and iron metabolism drive fibroblast activation in silicosis: insights from a novel 3D lung matrix model.

BACKGROUND

Silicosis is a lung disease marked by fibrosis and nodule formation, yet the impact of iron metabolism on these processes remains unclear. Existing models lack the ability to replicate the microenvironmental complexity needed to study iron-driven fibroblast activity. This study aimed to explore the role of iron metabolism in the progression of silicosis using a novel in vitro 3D culture system.

METHODS

In this study, a 3D spheroid model was established using lung decellularized matrix (LDM) particles and murine lung fibroblasts (NIH/3T3). Silica-stimulated macrophage supernatant was added to simulate fibrotic conditions. Histological staining, RNA sequencing, and iron quantification were conducted to investigate matrix production, fibroblast proliferation, and oxidative stress dynamics. Two ferroptosis inhibitors, deferoxamine (DFO) and ferrostatin-1 (Fer-1), were utilized to clarify the impact of iron metabolism on fibrotic processes.

RESULTS

The LDM-supported spheroid model successfully mimicked in vivo-like conditions. Histological analysis confirmed that LDM improved fibroblast viability and preserved extracellular matrix architecture. Silica-stimulated spheroids showed enhanced fibroblast proliferation, matrix production, and altered iron metabolism. Iron accumulation was associated with increased oxidative stress and disrupted Nrf2-SLC7A11 signaling. The addition of DFO inhibited fibroblast proliferation, while Fer-1 promoted it, highlighting the dual effects of iron metabolism on fibrotic progression.

CONCLUSIONS

This study highlights the dual role of iron metabolism in the regulation of fibroblast activity and extracellular matrix dynamics. The 3D spheroid model provides a novel platform to elucidate silicosis pathogenesis and advance antifibrotic therapeutic strategies.

KEY MESSAGES: A novel 3D model to study silicotic nodule formation and fibroblast activation. LDM and silica-stimulated supernatants promote fibroblast proliferation around spheroids. Silica exposure induces unique cell death patterns, with ferroptosis as a key mechanism. Disruption of Nrf2/SLC7A11/GPX4 axis links ferroptosis to fibrosis progression. Iron metabolism influences fibroblast activity and ferroptosis in silicosis.