020 Sphingosine 1-phosphate receptor signalling promotes hair growth and inhibits perifollicular T-cell expansion and immune privilege collapse ex vivo

Abstract

Sphingosine 1-phosphate (S1P) is a bioactive phospholipid that signals through five cell surface receptors (S1P1-5). Despite the role of S1P receptors in lymphocyte trafficking and epidermal keratinocyte proliferation and differentiation, their role in hair follicle (HF) physiology remains obscure. We hypothesized that S1P receptor activation may be involved in alopecia areata (AA), a T cell-mediated hair loss disorder characterized by immune privilege (IP) collapse in the hair bulb. RNAseq revelated S1P1,3,5 are expressed in human scalp HFs.