Regulatory T cells from injured skeletal muscle

A phenotypically and functionally distinct population of CD4+ Foxp3+ T cells (Tregs) rapidly accumulates in acutely injured skeletal muscle of mice, just as invading myeloid-lineage cells switch from a pro-inflammatory to a pro-regenerative state. Analysis of gene expression of Tregs and CD4+Foxp3- T cells (Tconvs) from injured muscle and spleen revealed that the transcriptome of muscle Treg cells is distinct from that of splenic Tregs. A set of genes is uniquely expressed by muscle Tregs, while another set is over-expressed by the two muscle populations vis-à-vis their two spleen counterparts. 6 wk-old Foxp3-ires-GFP mice were injured in skeletal muscles with cardiotoxin. Four and fourteen days later, Tregs and Tconvs from spleen and muscle were double-sorted into Trizol. To reduce variability, cells from multiple mice were pooled for sorting, and three replicates were generated for all groups. RNA from 1.5-2.5 x 104 cells was amplified, labeled, and hybridized to Affymetrix Mouse Gene 1.0 ST Arrays.