Neuropeptide S receptor 1 expression in the intestine and skin – putative role in peptide hormone secretion

Abstract

Neuropeptide S receptor 1 (NPSR1) was recently found to be genetically associated with inflammatory bowel disease in addition to asthma and related traits. Epithelia of several organs express NPSR1 isoforms A and B, including the intestine and the skin, and NPSR1 appears to be upregulated in inflammation. In this study, we used cell lines and tissue samples to characterize the expression of NPSR1 and its ligand neuropeptide S (NPS) in inflammation. We used polyclonal and monoclonal antibodies to investigate the expression of NPS and NPSR1 in intestinal diseases, such as celiac disease and food allergy, and in cutaneous inflammatory disorders. We found that NPSR1-A was expressed by the enteroendocrine cells of the gut. Overall, the expression pattern of NPS was similar to its receptor suggesting an autocrine mechanism. In an NPSR1-A overexpressing cell model, stimulation with NPS resulted in a dose-dependent upregulation of glycoprotein hormone, alpha polypeptide (CGA), tachykinin 1 (TAC1), neurotensin (NTS) and galanin (GAL) encoding peptide hormones secreted by enteroendocrine cells. Because NPSR1 was also expressed in macrophages, neutrophils, and intraepithelial lymphocytes, we demonstrated that stimulation with the pro-inflammatory cytokines tumour necrosis factor alpha and interferon gamma increased NPSR1 expression in the THP-1 monocytic cells. In conclusion, similar to other neuropeptides and their receptors, NPSR1 signalling might play a dual role along the gut-brain axis. The NPS/NPSR1 pathway may participate in the regulation of the peptide hormone production in enteroendocrine cells of the small intestine.

Neuropeptide S inhibits gastrointestinal motility and increases mucosal permeability through nitric oxide

“…Since the permeability tests in our study were performed in vivo, this could have been driven directly within the mucosal epithelium, known to possess NPS as well as NPSR1 (3,20). The gastrointestinal mucosa is also generally known to express NOS (7), so blockade of the NPS effect by L-NAME might even occur within these same cells.…”

Neuropeptide S receptor 1 (NPSR1) activates cancer-related pathways and is widely expressed in neuroendocrine tumors

“…The specificity of these antibodies has been previously characterized using flow cytometry, immunoblotting experiments, and immunostaining of skin and small intestine sections [7, 30]. In the current study, epitope specificity of the monoclonal anti-NPSR1 antibodies was further studied in immunoblotting experiments of recombinant NPSR1 constructs expressing the corresponding peptide sequences produced in E. coli and by immunocytochemistry of the COS-7 cell line transfected with recombinant full-length NPSR1 constructs.…”

“…For immunohistochemistry, mouse monoclonal antibodies against the synthetic peptide CREQRSQDSRMTFRERTER of the C-terminus of isoform A (NPSR1-A, amino acids 336–354) and against the synthetic peptide TEGSFDSSGTGQTLDSSPVA (NPSR1-N, amino acids 6–20) corresponding to the extracellular N-terminus of NPSR1 were used [7, 30]. Anti-mouse IgG antibodies (1:4,000,000, R0614, Vector) were used as an isotype control.…”

“…NPSR1 encodes several splice variants in humans, but only two full-length variants with unique intracellular carboxy-termini, NPSR1-A and NPSR1-B, are expressed on the cell surface [2]. NPSR1 is mostly expressed in the central nervous system [3], but also in specific peripheral cell types, such as monocytes/macrophages [4–6] and neuroendocrine cells of the gut [7, 8]. The NPSR1 locus has shown genetic associations with inflammatory diseases, such as asthma [9–16], inflammatory bowel disease [17], and rheumatoid arthritis [18, 19], as well as with anxiety [20] and various stress-related phenotypes [21–24].…”

“…In addition, NPS modulates cell growth of human Colo205 colon cancer cells [1] and porcine splenic lymphocytes [5]. In an NPSR1-A overexpressing human embryonic kidney epithelial cell line, NPS stimulation increased expression of genes that encode peptide hormones and neuropeptides secreted by enteroendocrine cells [7]. Transcriptome analyses revealed that NPSR1-A and NPSR1-B regulate essentially identical sets of genes, but the signaling effects were stronger with NPSR1-A [29, 30].…”