Sensory neuronal control of skin barrier immunity.

Skin-innervating sensory neurons recognize a diverse array of exogenous and endogenous stimuli, including pathogens, allergens, tissue-derived alarmins, and immune-derived cytokines. Neuropeptides derived from sensory neurons signal to immune cells in the skin to promote or dampen innate immune responses to external insults. Sensory neurons influence the mode and magnitude of antigen-specific adaptive cutaneous immune responses by altering dendritic cell activation, migration, and priming of naïve T cells. Dendritic cell populations in mouse skin and skin-draining lymph nodes express mRNAs of numerous neuropeptide receptor genes, presenting ample opportunities for future investigation into neuronal control of cutaneous immunity. Skin-innervating sensory neurons detect noxious stimuli and release neuropeptides to control and shape mammalian innate and adaptive immune responses to external insults. Peripheral sensory neurons recognize diverse noxious stimuli, including microbial products and allergens traditionally thought to be targets of the mammalian immune system. Activation of sensory neurons by these stimuli leads to pain and itch responses as well as the release of neuropeptides that interact with their cognate receptors expressed on immune cells, such as dendritic cells (DCs). Neuronal control of immune cell function through neuropeptide release not only affects local inflammatory responses but can impact adaptive immune responses through downstream effects on T cell priming. Numerous neuropeptide receptors are expressed by DCs but only a few have been characterized, presenting opportunities for further investigation of the pathways by which cutaneous neuroimmune interactions modulate host immunity. [ABSTRACT FROM AUTHOR]