Professor Guangzhou Medical University Guangzhou, Guangdong, China (People's Republic)
Introduction/Rationale: Although generally stable, Tregs can lose Foxp3 under inflammatory cues, converting to exTregs. The epigenetic basis of this conversion and its impact on immunotherapy remain unclear. Given that BATF regulates effector Treg function and recruits CTCF for epigenomic remodeling in activated CD4+ T cells, we asked whether CTCF similarly controls effector Treg development and immune responses via 3D genome organization.
Methods: We generated Treg-specific CTCF knockout mice by crossing Ctcf fl/fl mice with Foxp3-Cre or Foxp3-CreERT2 strains. These models were evaluated under steady-state, inflammatory, and tumor conditions (including melanoma). Multi-omics profiling included RNA-seq, ATAC-seq, CTCF CUT&Tag, Hi-C, and single-cell RNA/TCR sequencing to assess transcriptional, epigenetic, and spatial genome architecture in Tregs. We also analyzed scRNA-seq data from cancer patients treated with immune checkpoint inhibitors, focusing on Treg differentiation states and their interactions with other immune cells. Responses to immune checkpoint blockade (ICB) were further examined in tumor-infiltrating Tregs.
Results: We generated Treg-specific CTCF knockout mice using Foxp3-Cre or Foxp3-CreERT2 strains. Models were studied under steady-state, inflammatory, and tumor conditions. Multi-omics approaches included RNA-seq, ATAC-seq, CTCF CUT&Tag, Hi-C, and single-cell RNA/TCR sequencing. We also analyzed scRNA-seq data from immune checkpoint inhibitor-treated cancer patients, focusing on Treg differentiation and cell-cell interactions. ICB effects were assessed in tumor-infiltrating Tregs.
Conclusion: CTCF maintains Treg lineage integrity through 3D genome organization, thereby restraining exTreg differentiation and supporting immune tolerance. Our findings further suggest that exTregs may activate migratory dendritic cells, contributing to both antitumor immunity and immune-related adverse events in patients receiving checkpoint inhibitors.
