Glial-immune interactions in barrier organs.

Neuro-immune interactions within barrier organs, such as lung, gut, and skin, are crucial in regulating tissue homeostasis, inflammatory responses, and host defence. Our rapidly advancing understanding of peripheral neuroimmunology is transforming the field of barrier tissue immunology, offering a fresh perspective for developing therapies for complex chronic inflammatory disorders affecting barrier organs. However, most studies have primarily examined interactions between the peripheral nervous system and the immune system from a neuron-focused perspective, while glial cells, the nonneuronal cells of the nervous system, have received less attention. Glial cells were long considered as mere bystanders, only supporting their neuronal neighbours, but recent discoveries mainly on enteric glial cells in the intestine have implicated these cells in immune-regulation and inflammatory disease pathogenesis. In this review, we will highlight the bi-directional interactions between peripheral glial cells and the immune system and discuss the emerging immune regulatory functions of glial cells in barrier organs.