Neuromedin Elicits Cytokine Release in Murine Th2-Type T Cell Clone D10.G4.1

Abstract

Neuromedin U (NmU), originally isolated from porcine spinal cord and later from other species, is a novel peptide that potently contracts smooth muscle. NmU interacts with two G protein-coupled receptors designated as NmU-1R and NmU-2R. This study demonstrates a potential proinflammatory role for NmU. In a mouse Th2 cell line (D10.G4.1), a single class of high affinity saturable binding sites for 125I-labeled NmU (KD 364 pM and Bmax 1114 fmol/mg protein) was identified, and mRNA encoding NmU-1R, but not NmU-2R, was present. Competition binding analysis revealed equipotent, high affinity binding of NmU isopeptides to membranes prepared from D10.G4.1 cells. Exposure of these cells to NmU isopeptides resulted in an increase in intracellular Ca2+ concentration (EC50 4.8 nM for human NmU). In addition, NmU also significantly increased the synthesis and release of cytokines including IL-4, IL-5, IL-6, IL-10, and IL-13. Studies using pharmacological inhibitors indicated that maximal NmU-evoked cytokine release required functional phospholipase C, calcineurin, MEK, and PI3K pathways. These data suggest a role for NmU in inflammation by stimulating cytokine production by T cells.

Neuromedin U is regulated by the metastasis suppressor RhoGDI2 and is a novel promoter of tumor formation, lung metastasis and cancer cachexia

“…This is consistent with the evidence that tumor-microenvironment Neuromedin U enhances lung metastasis Y Wu et al interactions affect local cancer growth, invasion and metastasis (Chung et al, 2005). NMU can also induce the release of inflammatory cytokines in T helper-2 (Th2)-type T cells, mast cells or macrophages (Johnson et al, 2004;Moriyama et al, 2005Moriyama et al, , 2006. These cytokine-releasing immune cells may stimulate neovascularization to promote the growth of neoplasms in humans.…”

“…NMU itself has an anorexigenic effect in animals (Howard et al, 2000;Hanada et al, 2004;Shousha et al, 2006), and transgenic overexpression of it promotes leanness in mice (Kowalski et al, 2005). As NMU can function as a proinflammatory mediator by promoting interleukin (IL)-6 production in Th2-type T cells or macrophages (Johnson et al, 2004;Moriyama et al, 2006) and inhibition of IL-6 can partially attenuate or reverse cancer cachexia (Strassmann and Kambayashi, 1995), this might be a mechanism underlying NMU-mediated cancer cachexia.…”

Neuromedin U: A Multifunctional Neuropeptide with Pleiotropic Roles

“…Interestingly, c-Met also appears to be upregulated following NmU treatment, suggesting a positive loop between these 2 molecules (131 ). Regarding other genes that are regulated by NmU, this peptide appears to be required for secretion of IL-6, a cytokine involved in cancer cell growth and cachexia (124 ), although it is not clear whether NmU affects IL-6 mRNA concentrations (123,135 ). NmU was also found to positively regulate Forkhead box protein M1 (FOXM1), a transcription factor and human protooncogene (45 ).…”

“…NmU was first shown to induce synthesis and release of several different cytokines [interleukin-4 (IL-4), IL-5, IL-6, IL-10, and IL-13) from a mouse T-helper 2 cell line in an NMUR1-dependent fashion (123 ). It was later shown that NmU is required for IL-6 production, as shown by impaired IL-6 secretion by macrophages in NmU Ϫ/Ϫ mice (124,125 ).…”

“…It was later shown that NmU is required for IL-6 production, as shown by impaired IL-6 secretion by macrophages in NmU Ϫ/Ϫ mice (124,125 ). However, the exact role of NmU in regulating cytokine production is still unknown, as are the signaling pathways where this peptide is involved, although phospholipase C, calcineurin, and the MEK and PI3K (phosphatidylinositol 3-kinase) pathways are known to be required for this effect (123 ). It is clear, though, that NmU has the ability to modulate the immune response.…”