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Neuroregulation of Pulmonary Immune Responses by Vasoactive Intestinal Peptide and Substance P
Published in Sami I. Said, Proinflammatory and Antiinflammatory Peptides, 2020
Edward J. Goetzl, Sunil P. Sreedharan, Patricia K. Byrd, H. Benfer Kaltreider, Menghang Xia
VIP and PACAP are bound with nearly the same affinity by two receptors (Rs) with seven transmembrane domains, which are designated the type I VIPR (VIPR1) or type IIPACAPR and the type II VIPR (VIPR2) or type III PACAPR (Table 1). VIPR1 and VIPR2 are members of a distinct family of G-protein-associated Rs that also includes Rs for other large peptides, such as secretin, calcitonin, and parathyroid hormone. Rs of the VIP/PACAP family have only 15% or less homology with other members of the superfamily of G-protein-associated Rs and lack the signature sequences of the β-adrenergic R family, but exhibit up to 50% homology between family members, which all have long extracellular amino-terminal domains with eight conserved cysteines (1,54—57). Although the amino acid (aa) sequences of the 457-aa VIPRl and the 437-aa VIPR2 of humans are only 49% identical (Table 1), the expression of either type alone by transfectants and cultured cell lines results in VIP binding of the same specificity, as defined by competition with related peptides (57–59). The affinity of binding of VIP is approximately 10-fold higher for VIPR 1 than for VIPR2, but at these respective concentrations both VIPRl and VIPR2 signal increases in the intracellular concentrations of cyclic AMP ([cAMP].) and Ca2+ ([Ca2+]i), which are similar in magnitude (Table 1). To date, a series of novel peptide analogs of VIP are the only ligands known to usefully distinguish between VIPRl and VIPR2 at the levels of binding and biochemical signals.
Targeted Radiolabeled Receptor-Avid Peptides
Published in Martin G. Pomper, Juri G. Gelovani, Benjamin Tsui, Kathleen Gabrielson, Richard Wahl, S. Sam Gambhir, Jeff Bulte, Raymond Gibson, William C. Eckelman, Molecular Imaging in Oncology, 2008
Vasoactive intestinal peptide (VIP) is a neuropeptide and a member of the glucagons secretion family and closely related to pituitary adenylate cyclase–activating polypeptide (PACAP) (3,5,6,178). Both are G protein-coupled receptors that can be internalized after ligand binding (179). VIP is a 28–amino acid peptide while PACAP has a similar structure with 27 or 38 amino acids (3,5,6,178). There are two VIP receptor subtypes, VIPR1 and VIPR2, both exhibiting high binding affinity for VIP and PACAP (5). VIP/PACAP receptors are found not only in brain but ubiquitously by a majority of human epithelial tissues (179,180). The VIPR1 subtype is preferentially expressed by most of these tissues, including hepatocytes, gastrointestinal mucosa, pancreatic ducts, among others (5,178–180). The presence of VIP/PACAP receptors in most normal tissue points to multiple and complex biological actions of VIP/PACAP peptides in the human body (5).
Association of VIPR2 and ZMAT4 with high myopia
Published in Ophthalmic Genetics, 2020
Kai Xiong Cheong, Rita Yu Yin Yong, Mellisa Mei Hui Tan, Frederick Lian Kheng Tey, Bryan Chin Hou Ang
Vasoactive intestinal peptide receptor 2 (VIPR2) is a G-protein coupled receptor and is located on chromosome 7q36, which is located within the interval for a putative locus for autosomal dominant high-grade myopia (16,17). VIPR2 is involved in cell proliferation, division and differentiation of retinal cells through stimulatory or inhibitory effects (18,19). The expression of VIPR2 in the retina and the choroid has also been shown to be altered in chicks with form-deprivation myopia (20,21). A GWAS on a Han Chinese population reported a significant association between RS2730260 and high myopia (19). Separately, there were also significant associations found between VIPR2 and high myopia using both Single Nucleotide Polymorphisms (SNP) (RS2071625) and haplotype analysis (RS2071623-RS2071625-RS2730220-RS885863) in a Han Chinese population (22). In addition, another study on participants of mainly European ancestry demonstrated that VIPR2 was a susceptibility locus for refractive errors in a large cohort of participants (23). These findings indicate a role of VIPR2 in high myopia pathogenesis.
Neuropeptide changes in the suprachiasmatic nucleus are associated with the development of hypertension
Published in Chronobiology International, 2019
Ajda Yilmaz, Frederik N Buijs, Andries Kalsbeek, Ruud M Buijs
In mammals, the SCN has at least two functionally distinct compartments (Shinohara et al. 1995). The retinorecipient core region contains VIP and self-oscillatory dorsal cap- shell- region contains mainly AVP (Reghunandanan and Reghunandanan 2006; van Den Pol 1980). Interestingly, interactions between these two regions and coupling within the SCN are maintained mainly by VIP signaling. One of the VIP receptors, Vipr2, has a major role in light signaling in the SCN and signaling between core and shell. Interestingly, Vipr2 knockout mice (Vipr2-/-) lose synchrony within the SCN (Aton et al. 2005; Harmar 2003) and also have abnormal blood pressure and heart rate rhythms and abnormal patterns of locomotor activity (Sheward et al. 2010). All these observations imply the involvement of VIP signaling in cardiovascular and locomotor activity regulation, besides light responsiveness and maintaining the synchrony within the SCN. In accordance with the above literature, SHRs have abnormalities in their cardiovascular rhythms (Minami et al. 1988; Munakata et al. 1990) and they have shorter but increased amplitude of their locomotor activity rhythms in constant darkness (Yilmaz et al. 2018). In the current study, correlational analysis revealed significant negative correlations between VIP expression levels and HR levels in SHRs but a positive, not significant, correlation between VIP lateral expression levels and systolic blood pressure (SBP) levels is observed in WKYs at the age of 12 weeks. In contrast to WKYs, a strong negative correlation between VIP lateral expression levels and SBP is observed in 2K1C-hypertensive rats (see results). Moreover, by taking into account the overall neuro-anatomical changes described here it is highly tempting to speculate a crucial role of the interplay between two different VIP sub-compartments and the AVP region of the SCN for regulating blood pressure control in health and disease (Figure 7).