Regulation of endogenous human NPFF2 receptor by neuropeptide FF in SK‐N‐MC neuroblastoma cell line

Abstract

Neuropeptide FF has many functions both in the CNS and periphery. Two G protein-coupled receptors (NPFF1 and NPFF2 receptors) have been identified for neuropeptide FF. The expression analysis of the peptide and receptors, together with pharmacological and physiological data, imply that NPFF2 receptor would be the primary receptor for neuropeptide FF. Here, we report for the first time a cell line endogenously expressing hNPFF2 receptor. These SK-N-MC neuroblastoma cells also express neuropeptide FF. We used the cells to investigate the hNPFF2 receptor function. The pertussis toxin-sensitive inhibition of adenylate cyclase activity upon receptor activation indicated coupling to G i/o proteins. Upon agonist exposure, the receptors were internalized and the mitogen-activated protein kinase cascade was activated.Upon neuropeptide FF treatment, the actin cytoskeleton was reorganized in the cells. The expression of hNPFF2 receptor mRNA was up-regulated by neuropeptide FF. Concomitant with the receptor mRNA, the receptor protein expression was increased. The homologous regulation of hNPFF2 receptor correlates with our previous results in vivo showing that during inflammation, the up-regulation of neuropeptide FF mRNA precedes that of NPFF2 receptor. The regulation of hNPFF2 receptor by NPFF could also be important in the periphery where neuropeptide FF has been suggested to function as a hormone.

Identification and Functional Characterization of the Phosphorylation Sites of the Neuropeptide FF2 Receptor

“…However, the potency of 1DMe is increased by more than 1 order of magnitude in the rat species. ERK activation by NPFF 2 receptors has been demonstrated previously in rat and human cell lines that were shown to endogenously express the receptor (14,37,38). Here we confirm the specificity of this effect by using recombinant cells.…”

“…The receptor was demonstrated to couple to G i/o heterotrimeric proteins to inhibit adenylyl cyclase (10) and N-type voltagegated calcium channels (11) and activate G protein-regulated inwardly rectifying potassium channels (12), as well as a putative delayed rectifier K ϩ channel (13). It was also shown to activate MAPK pathways (14). However, the mechanisms regulating NPFF 2 receptor signaling and trafficking have not been studied in detail.…”

Evolutionary Origin of GnIH and NPFF in Chordates: Insights from Novel Amphioxus RFamide Peptides

“…Our previous study showed that GnIH directly inhibits cAMP production induced by GnRH in the mouse gonadotrope cell line, LβT2 [38]. Interestingly, NPFF also inhibited FSK-stimulated CRE-luciferase activity [41] or inhibited cAMP levels [42]. The present study suggests that amphioxus PQRFa peptides act as inhibitory peptides on the neuroendocrine system of reproduction and their mode of action is similar to those of vertebrate GnIH and NPFF group peptides.…”

Adrenomedullin increases the expression of calcitonin-like receptor and receptor activity modifying protein 2 mRNA in human microvascular endothelial cells

“…Transcriptional regulation of receptors by their ligands has been shown in various different studies. Exposure of agonists to G protein-coupled receptors frequently results in downregulation of the receptor transcript levels, but receptor upregulation has also been demonstrated (Siegrist et al 1994, Schanstra et al 1998, Froidevaux & Eberle 2002, Ankö & Panula 2006. Inoue et al (1999) found that calcitonin downregulates calcitonin receptor mRNA in mouse bone marrow cells and Dupre et al (2003) report the ligand-induced downregulation of the PAF-R. On the other hand, gene expression of the human somatostatin receptor type I is actively upregulated by somatostatin (Hukovic et al 1999).…”