GPR15L is an epithelial inflammation-derived pruritogen.

Area of Science:

• Immunology
• Neuroscience
• Dermatology

Background:

• Chronic skin conditions like psoriasis and atopic dermatitis are frequently associated with debilitating itch.
• While itch pathways are partially understood, endogenous itch-inducing molecules (pruritogens) remain largely unidentified.

Purpose of the Study:

• To identify novel endogenous pruritogens involved in chronic itch.
• To investigate the role of GPR15L in itch signaling and mast cell activation.

Main Methods:

• Unbiased bioinformatics analysis to identify candidate pruritogens.
• In vitro studies using dorsal root ganglion neurons and mast cells.
• In vivo experiments using a mouse model of psoriasis.

Main Results:

• GPR15L expression is significantly upregulated in psoriasis and atopic dermatitis.
• GPR15L activates Mas-related G protein-coupled receptors (MRGPRs), specifically Mrgpra3 on sensory neurons, inducing itch.
• GPR15L triggers mast cell degranulation via MRGPRX2 and Mrgprb2.
• Disrupting GPR15L attenuated scratching behavior in a mouse psoriasis model.

Conclusions:

• GPR15L is a novel, potent pruritogen contributing to itch in chronic dermatological diseases.
• GPR15L acts through both neuronal and mast cell pathways to induce itch.
• Targeting GPR15L may offer a therapeutic strategy for managing chronic itch.