T Cell-Derived IFN-γ Activates Ferroptosis in Lacrimal Luminal Ductal Cells via JAK-STAT Signaling in Sjögren's Disease-Related Dry Eye.

PURPOSE: Sjögren's disease (SjD) leads to severe dry eye disease (DED) via lacrimal gland inflammation and dysfunction, yet the specific pathogenic mechanisms remain unclear. In this study, we aimed to deeply identify the vulnerable lacrimal epithelial subclusters and elucidate the immune-epithelial cross-talk.

METHODS

We used MRL/lpr mice as a murine SjD model and integrated bioinformatic analysis of single-cell RNA-sequencing (scRNA-seq) and spatial transcriptome datasets. These findings were validated using immunofluorescence (IF), multiplex immunohistochemistry analysis (mIHC), Western blot, transmission electron microscopy (TEM), and flow cytometry. Finally, an in vivo interferon-γ (IFN-γ) neutralization strategy was implemented, with therapeutic effects evaluated by the phenol red thread test and lissamine green staining.

RESULTS

ScRNA-seq and spatial analyses converged to identify luminal ductal epithelia (LDE), marked by CYP2F2, as the primary epithelial population damaged in SjD. This was further correlated with the specific upregulation of both Janus kinase/signal transducer and activator of transcription (JAK-STAT) signaling and ferroptosis pathway. We then confirmed that this periductal damage was driven by the infiltration of IFN-γ-secreting T helper 1 (Th1) cells. TEM analysis validated classical ferroptotic mitochondrial damage specifically in LDE. Systemic IFN-γ neutralization suppressed local Th1 infiltration, which in turn significantly downregulated the JAK2/STAT1 pathway and reversed ferroptosis within LDE. This intervention significantly alleviated DED signs, as evidenced by increased tear secretion and reduced corneal lissamine green staining.

CONCLUSIONS

Our findings define a spatially-specific pathogenic axis where infiltrating Th1 cells release IFN-γ to trigger a JAK-STAT and ferroptosis cascade in LDE, highlighting IFN-γ neutralization as a promising therapeutic strategy.