Distinct Injury Responsive Regulatory T Cells Identified by Multi-Dimensional Phenotyping

Area of Science:

• Immunology
• Cell Biology
• Tissue Repair

Background:

• CD4+ regulatory T cells (Tregs) are crucial for immune homeostasis and tissue repair.
• Tregs activate and expand following various injuries, indicating a key role in managing immune responses to damage.

Purpose of the Study:

• To comprehensively characterize injury-responsive Tregs using multi-dimensional profiling in mice.
• To identify distinct transcriptional and phenotypic profiles of Tregs that expand after injury.

Main Methods:

• Multi-dimensional profiling, including T cell receptor (TCR) repertoire analysis.
• Bulk and single-cell RNA sequencing with paired TCR clonotype analysis.
• Mass cytometry (CyTOF) for protein expression verification.

Main Results:

• CD44-high Tregs expanded in response to injury and exhibited higher suppressive function than CD44-low Tregs.
• TCR repertoire analysis showed clonal expansion and increased diversity in CD44-high Tregs.
• RNA sequencing revealed unique gene expression in CD44-high Tregs, enriched for chemokine receptors and cell division genes. CyTOF confirmed increased Helios, Galectin-3, and PYCARD expression.

Conclusions:

• Injury induces the expansion of a distinct, highly suppressive CD44-high Treg population.
• These CD44-high Tregs are transcriptionally and phenotypically different from CD44-low Tregs.
• Expanded CD44-high Tregs actively participate in regulating immune responses to injury and tissue damage.