VIP is a well-characterized peptide with a molecular weight of 3.3 kDa and consisting of 28 amino acids. This peptide regulates a broad spectrum of biological activities including vasodilatation, stimulation of secretion of various hormones, immunomodulation and promotion of cell proliferation. Newly developed antagonists appear to inhibit tumour growth in tumour-bearing nude mice and in certain neuroendocrine cell lines. These biological effects of VIP are mediated by its interaction with Gprotein-coupled receptors. Two VIP receptors with similar high binding affinities for VIP have been cloned and characterized: The VIP subtype 1 receptor, so-called Vpac 1 receptor, was isolated from rat lung, human colon adenocarcinoma cell line HT 29 and human jejunal epithelial cells by screening cDNA libraries. The Vpac 2 receptor was cloned from the rat olfactory bulb and the human SUP-T1 lymphoblast cell line.
An overview of vasoactive intestinal peptide (VIP) receptors
The VIP is cut from the preprohormone of 170 amino acids, which is similar to PHI, PACAP, GHRH and pancreas secretion and belongs to the secretin-glucagon family. The entire molecule of the VIP receptor consists of three parts, including N-terminal cell outland containing N-glycosylation sites, transmembrane domains, containing seven hydrophobic transmembrane fragments, and C-terminal cytoplasm field. VIP receptors are widely distributed in many tissues and organs of humans and animals.
Major types of vasoactive intestinal peptide (VIP) receptors
According to the distribution of receptor and the affinity between receptor and ligand, it is divided into two categories, including VIP1 receptor and VIP2 receptor. The VIP1 receptors are mainly distributed in peripheral tissues such as lungs, small intestine, liver, spleen, pancreas, aorta, and central nervous system mainly in midbrain, rarely in other brain regions. VIP2 receptors are more widely distributed than VIP1 receptors, and are distributed in almost all tissues, such as small intestine, spleen, islet, kidney, testis, and ovary, no expression in the liver or aorta.
Inhibition of vasoactive intestinal peptide (VIP) receptors
VIP Hybrid is a kind of non-selective VIPR inhibitor, which can obviously inhibit the proliferation of breast cancer cells, and is antagonistic to the expression of cofs and c-myc induced by the VIP.
Vasoactive intestinal peptide (VIP) receptors and diseases
Because of the wide distribution of VIP receptor in central and peripheral tissues and the diversity of its mediated physiological function, it suggests that it is related to some diseases, and further raises its value in clinical diagnosis and treatment. Some scholars have suggested that possible application prospects include the treatment of bronchial asthma, the treatment of impotence, coronary heart disease, hypertension , left ventricular failure with increased local blood supply, and the early differential diagnosis of different types of leukemia and myeloid leukemia recurrence. Moreover, a large number of studies in vitro have shown that there are high-density and high-affinity VIP receptors expressed in various tumor cells, including gastrointestinal pancreatic tumors, small cell lung cancer, meningioma, multiple pathological types of breast cancer, neuroblastoma and tumors with high incidence or high mortality.