The many faces of VIP in neuroimmunology: a cytokine rather a neuropeptide?
Neuroimmunomodulation has experienced an explosive growth not only in basic research, but expanding to the point that prospective clinical research could be now a reality. A crucial factor for the functioning of this intimate bidirectional network was the demonstration that the immune and neuroendocrine systems speak a mutual biochemical language. This implies 1) production of neuroendocrine hormones and neuropeptides by immune cells and of cytokines by neuroendocrine cells; 2) evidence for shared receptors on cells of the immune and neuroendocrine systems; 3) effect of neuroendocrine mediators on immune functions; and 4) effect of cytokines on the neuroendocrine system. This reduces traditional differences between neurotransmitters, hormones, and immune mediators and raises the following question: what can we now regard as immune or neuroendocrine? Vasoactive intestinal peptide (VIP) is one example of this paradigm. VIP has traditionally been classified as a neuropeptide/neurotransmitter based in its capacity to mediate and regulate neuronal functions. Recent work has demonstrated that VIP is produced by T cells, especially Th2 cells, and that through specific receptors it exerts immunological functions typically ascribed to Th2 cytokines in nervous and immune systems. Here, we postulate that instead of a neuropeptide, VIP could be fully considered a type 2 cytokine with a key role in neuroimmunology.
Pozo
David
D
Department of Medical Biochemistry and Molecular Biology, University of Seville, Seville, Spain.
Delgado
Mario
M
D000486:Allergy and Immunology; D000818:Animals; D016207:Cytokines / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000378:metabolism; D008954:Models, Biological; D009462:Neurology; D009479:Neuropeptides / Q000276:immunology / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000276:immunology* / Q000378:metabolism*
D016207:Cytokines; D009479:Neuropeptides; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide