- Ali, Niwa;
- Zirak, Bahar;
- Rodriguez, Robert Sanchez;
- Pauli, Mariela L;
- Truong, Hong-An;
- Lai, Kevin;
- Ahn, Richard;
- Corbin, Kaitlin;
- Lowe, Margaret M;
- Scharschmidt, Tiffany C;
- Taravati, Keyon;
- Tan, Madeleine R;
- Ricardo-Gonzalez, Roberto R;
- Nosbaum, Audrey;
- Bertolini, Marta;
- Liao, Wilson;
- Nestle, Frank O;
- Paus, Ralf;
- Cotsarelis, George;
- Abbas, Abul K;
- Rosenblum, Michael D
The maintenance of tissue homeostasis is critically dependent on the function of tissue-resident immune cells and the differentiation capacity of tissue-resident stem cells (SCs). How immune cells influence the function of SCs is largely unknown. Regulatory T cells (Tregs) in skin preferentially localize to hair follicles (HFs), which house a major subset of skin SCs (HFSCs). Here, we mechanistically dissect the role of Tregs in HF and HFSC biology. Lineage-specific cell depletion revealed that Tregs promote HF regeneration by augmenting HFSC proliferation and differentiation. Transcriptional and phenotypic profiling of Tregs and HFSCs revealed that skin-resident Tregs preferentially express high levels of the Notch ligand family member, Jagged 1 (Jag1). Expression of Jag1 on Tregs facilitated HFSC function and efficient HF regeneration. Taken together, our work demonstrates that Tregs in skin play a major role in HF biology by promoting the function of HFSCs.