Enteric glia: the most alimentary of all glia

Glia (from Greek γλοία meaning ‘glue’) pertains to non‐neuronal cells in the central (CNS) and peripheral nervous system (PNS) that nourish neurons and maintain homeostasis. In addition, glia are now increasingly appreciated as active regulators of numerous physiological processes initially considered exclusively under neuronal regulation. For instance, enteric glia, a collection of glial cells residing within the walls of the intestinal tract, regulate intestinal motility, a well‐characterized reflex controlled by enteric neurons. Enteric glia also interact with various non‐neuronal cell types in the gut wall such as enterocytes, enteroendocrine and immune cells and are therefore emerging as important local regulators of diverse gut functions. The intricate molecular mechanisms that govern glia‐mediated regulation are beginning to be discovered, but much remains unknown about the functions of enteric glia in health and disease. Here we present a current view of the enteric glia and their regulatory roles in gastrointestinal (GI) (patho)physiology; from GI motility and epithelial barrier function to enteric neuroinflammation. Enteric glia are local regulators of gut (patho)physiological processes. Enteric glial cells interact with neurons within the enteric nervous system (green box) and with many other cells within the wall of the alimentary canal. Recent studies demonstrated regulatory roles of enteric glia in gastrointestinal motility, inflammation/neuronal cell death and epithelial secretion/barrier function via active interplay with neurons, immune cells and enterocytes, respectively. Physiological effects of direct interplay between the enteric glia and muscle, vasculature and enteroendocrine cells are still unknown (?).