Homeostasis of the human immune system is regulated by many cellular components, including two neuropeptides, VIP and PACAP, primary stimuli for three class B G protein-coupled receptors, VPAC1, VPAC2, and PAC1. Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) regulate intestinal motility and secretion and influence the functioning of the endocrine and immune systems. Inhibition of VIP and PACAP receptors is an emerging concept for new pharmacotherapies for chronic inflammation and cancer, while activation of their receptors provides neuroprotection. A small number of known active compounds for these receptors still impose limitations on their use in therapeutics. Recent cryo-EM structures of VPAC1 and PAC1 receptors in their agonist-bound active state have provided insights regarding their mechanism of activation. Here, we describe major molecular switches of VPAC1, VPAC2, and PAC1 that may act as triggers for receptor activation and compare them with similar non-covalent interactions changing upon activation that were observed for other GPCRs. Interhelical interactions in VIP and PACAP receptors that are important for agonist binding and/or activation provide a molecular basis for the design of novel selective drugs demonstrating anti-inflammatory, anti-cancer, and neuroprotective effects. The impact of genetic variants of VIP, PACAP, and their receptors on signalling mediated by endogenous agonists is also described. This sequence diversity resulting from gene splicing has a significant impact on agonist selectivity and potency as well as on the signalling properties of VIP and PACAP receptors.
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http://dx.doi.org/10.3390/biomedicines10020406 | DOI Listing |
Front Immunol
December 2024
Institute of Forensic Medicine and Laboratory Medicine, Jining Medical University, Jining, China.
The defense mechanisms of the vertebrate brain against infections are at the forefront of immunological studies. Unlike other body parts, the brain not only fends off pathogenic infections but also minimizes the risk of self-damage from immune cell induced inflammation. Some neuropeptides produced by either nerve or immune cells share remarkable similarities with antimicrobial peptides (AMPs) in terms of size, structure, amino acid composition, amphiphilicity, and net cationic charge.
View Article and Find Full Text PDFPeptides
January 2025
Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas, Universidade Estadual de Londrina, Londrina, PR, Brazil; Programa de Pós-Graduação em Ciências Fisiológicas, Universidade Estadual de Londrina, Londrina, PR, Brazil; Laboratório de Fisiologia Neuroendócrina e Metabolismo, Departamento de Ciências Fisiológicas, Universidade Estadual de Londrina, Londrina, PR, Brazil. Electronic address:
Neurologia (Engl Ed)
June 2023
Servicio de Neurología, Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain. Electronic address:
J Headache Pain
October 2024
Dompé Farmaceutici SpA, Via Santa Lucia 6, 20122, Milano, Italy.
Int J Mol Sci
August 2024
School of Molecular Bioscience, University of Sydney, Sydney, NSW 2006, Australia.
Inflammation with expression of interleukin 6 (IL-6) in the central nervous system (CNS) occurs in several neurodegenerative/neuroinflammatory conditions and may cause neurochemical changes to endogenous neuroprotective systems. Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) are two neuropeptides with well-established protective and anti-inflammatory properties. Yet, whether PACAP and VIP levels are altered in mice with CNS-restricted, astrocyte-targeted production of IL-6 (GFAP-IL6) remains unknown.
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