Acute and chronic itch are burdensome manifestations of skin pathologies including allergic
skin diseases and
atopic dermatitis, but the underlying molecular mechanisms are not well understood. Cysteinyl
leukotrienes (CysLTs), comprising
LTC4,
LTD4, and
LTE4, are produced by immune cells during type 2
inflammation. Here, we uncover a role for
LTC4 and its signaling through the CysLT receptor 2 (CysLT2R) in itch. Cysltr2 transcript is highly expressed in dorsal root ganglia (DRG) neurons linked to itch in mice. We also detected CYSLTR2 in a broad population of human DRG neurons. Injection of
leukotriene C4 (
LTC4) or its nonhydrolyzable form NMLTC4, but neither
LTD4 nor
LTE4, induced dose-dependent itch but not
pain behaviors in mice. LTC4-mediated itch differed in bout duration and kinetics from pruritogens
histamine,
compound 48/80, and
chloroquine. NMLTC4-induced itch was abrogated in mice deficient for Cysltr2 or when deficiency was restricted to radioresistant cells. Itch was unaffected in mice deficient for Cysltr1, Trpv1, or mast cells (WSh mice). CysLT2R played a role in itch in the
MC903 mouse model of chronic itch and
dermatitis, but not in models of dry skin or
compound 48/80- or Alternaria-induced itch. In MC903-treated mice, CysLT levels increased in skin over time, and Cysltr2-/- mice showed decreased itch in the chronic phase of
inflammation. Collectively, our study reveals that
LTC4 acts through CysLT2R as its physiological receptor to induce itch, and CysLT2R contributes to itch in a model of
dermatitis. Therefore, targeting CysLT signaling may be a promising approach to treat inflammatory itch.