Layilin Regulates Treg Motility and Suppressive Capacity in Skin

Regulatory T cells (Tregs) are essential for maintaining immune tolerance in both lymphoid and non-lymphoid tissues. We discovered that layilin, a C-type lectin receptor, is predominantly expressed on Tregs in skin. Layilin was highly expressed on a subset of clonally expanded ‘effector’ Tregs in both healthy and psoriatic skin. Layilin expressing Tregs exhibited a transcriptional profile indicative of enhanced adhesion. Deletion of layilin in Tregs in vivo resulted in significantly attenuated skin inflammation. Mechanistically, layilin enhanced Treg adhesion via modulation of LFA-1, resulting in distinct cytoskeletal alterations consistent with enhanced focal adhesion and lamellipodia formation. Taken together, we define layilin as a critical regulator of Treg suppressive capacity through modulating motility and adhesion in a non-lymphoid tissue.