VIP and PACAP inhibit IL-12 production in LPS-stimulated macrophages. Subsequent effect on IFNγ synthesis by T cells
Introduction
Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase activating polypeptide (PACAP) are 28- and 38-aminoacid neuropeptides, respectively, which share 65% homology and perform a broad spectrum of biological functions affecting both natural and acquired immunity (Bellinger et al., 1996; De la Fuente et al., 1996). The immunological actions of VIP and PACAP are exerted through a family of VIP/PACAP receptors that were recently reclassified (Hamar et al., 1998): type 1 VIP receptor (VPAC1) and type 2 VIP receptor (VPAC2) which exhibit similar affinities for the two neuropeptides, and activate primarily the adenylate cyclase system, and PACAP receptor (PAC1) that exhibits a 300 to 1000-fold higher affinity for PACAP than for VIP, and activates both the adenylate cyclase and phospholipase C systems (Rawlings and Hezareh, 1996). Although VIP and PACAP affect a variety of immune functions, their primary immunomodulatory function is anti-inflammatory in nature. VIP and PACAP have been shown to inhibit T cell proliferation and cytokine production (Ganea, 1996), and to inhibit several macrophage functions, including phagocytosis, respiratory burst, and chemotaxis (De la Fuente et al., 1996), as well as lipopolysaccharide (LPS)-induced IL-6 and tumor necrosis factor α (TNFα) production (Hernanz et al., 1996; Martinez et al., 1998; Dewit et al., 1998; Delgado et al., 1999a). Furthermore, we have recently demonstrated that VIP and PACAP protect mice from endotoxic shock presumably by inhibiting the production of endogenous TNFα and IL-6 (Delgado et al., 1999b).
Interleukin-12 (IL-12), another early proinflammatory cytokine secreted by macrophages activated by microbial products, plays a central role in the regulation of cell-mediated immunity (Trinchieri, 1995, Trinchieri, 1998a, Trinchieri, 1998b). IL-12 stimulates the proliferation of activated T lymphocytes and enhances interferon gamma (IFNγ) secretion by NK cells and T lymphocytes. Consistent with this latter effect, IL-12 has a pivotal role in the induction of CD4+ Th1 cell responses, acting in antagonism to IL-4, the major promoter of the Th2 response (Hsieh et al., 1993; Manetti et al., 1993). In mice, IL-12 plays a decisive role in the protection against intracellular pathogens, including parasites and bacteria (Trinchieri, 1995, Trinchieri, 1998a, Trinchieri, 1998b). IL-12 is a unique cytokine because of its heterodimer structure. Bioactive IL-12 (p70) is composed of two disulfide-linked subunits (p35 and p40) encoded by two separate genes. When both subunits are produced within the same cell, they assemble into a biologically active heterodimer (Gubler et al., 1991). However, while the expression of the p35 gene is constitutive in a wide variety of cells, the p40 gene is highly tissue-regulated, being restricted to phagocytic cells with antigen-presenting capability (D'Andrea et al., 1992; Wolf et al., 1992).
Several lines of evidence suggest that the response of hemopoietic cells to endotoxin involves not only the rapid up-regulation of proinflammatory cytokines, but also the concomitant induction of potent anti-inflammatory factors (van Deuren et al., 1992; Laskin and Pendino, 1995). A complex regulatory network between the inflammatory mediators and effector cells determines the intensity and duration of inflammation. The ability to control an inflammatory state depends on the balance between the activities of proinflammatory and anti-inflammatory factors. A number of regulatory molecules termed `macrophage deactivating factors' have been the focus of considerable research lately (Kunkel et al., 1988; Tsunawaki et al., 1988; Fiorentino et al., 1991; Trepicchio et al., 1996; Muchamuel et al., 1997). The major role of such molecules, which include the cytokines IL-10, IL-13, and TGF-β1, is to prevent the excessive production of proinflammatory mediators. Neuropeptides such as VIP and PACAP with anti-inflammatory activity could be also included in the group of `macrophage deactivating factors'.
Previous reports showed that VIP/PACAP inhibit TNFα and IL-6 production in activated macrophages. In the present study, we examine the in vitro and in vivo effects of VIP/PACAP on IL-12 production by LPS-activated peritoneal macrophages, and the role of IL-12 as a mediator for the inhibitory activity of VIP/PACAP on IFNγ secretion by peritoneal T cells.
Section snippets
Reagents
Synthetic VIP, PACAP38, VIP1–12 and VIP10–28 were purchased from Novabiochem (Laufelfingen, Switzerland). The VPAC1-antagonist [Ac-His1, d-Phe2, K15, R16, L27] VIP [3–7]-GRF [8–27] and the VPAC1-agonist [K15, R16, L27] VIP [1–7]-GRF [8–27] were kindly donated by Dr. Patrick Robberecht (Universite Libre de Bruxelles, Belgium). The VPAC2-agonist Ro 25–1553 Ac-[Glu8, Lys12, Nle17, Ala19, Asp25, Leu26, Lys27,28, Gly29,30, Thr31]-VIP cyclo [21–25] was a generous gift from Drs. Ann Welton and David
VIP and PACAP inhibit LPS-induced IL-12 production by peritoneal macrophages
To investigate the effects of VIP and PACAP on IL-12 production, peritoneal macrophages were stimulated with different concentrations of LPS in the absence or presence of various doses of VIP or PACAP, and the amount of IL-12 released in the culture supernatants was assayed by ELISA at different time points. VIP and PACAP inhibit in a dose- and time-dependent manner the IL-12 production by LPS-stimulated cells (Fig. 1). The dose–response curves were similar for VIP and PACAP, showing maximal
Discussion
Phagocytic cells with antigen-presenting capability such as macrophages produce IL-12 in response to microbial stimuli. The bioactive IL-12 is a p35/p40 covalently bound heterodimer (Kobayashi et al., 1989; Gubler et al., 1991). While the p35 gene is expressed constitutively at low levels in most cell types, the expression of p40 is restricted to bioactive IL-12 producing cells (D'Andrea et al., 1992; Wolf et al., 1992). We used preferentially an IL-12p40 ELISA in our experiments, because of
Acknowledgements
This work was supported by grants PHS AI 41786-01 (DG), and Busch Biomedical Award 96–98 (DG), grant PB94-0310 (RPG), PM98-0081 (RPG and MD) and by the postdoctoral fellowship from the Spanish Department of Education and Science (MD). We thank Dr. Patrick Robberecht (Universite Libre de Bruxelles, Brussels, Belgium) for the VPAC1 agonist and antagonist, Drs. David Bolin and Ann Welton (Hoffmann–LaRoche, Nutley, NJ) for the VPAC2 agonist Ro 25–1553, and Dr. Ethan Lerner (Massachusetts General
References (69)
- et al.
The significance of vasoactive intestinal peptide (VIP) in immunomodulation
Adv. Neuroimmunol.
(1996) - et al.
Functional and molecular characterization of VIP receptors and signal transduction in human and rodent systems
Adv. Neuroimmunol.
(1996) - et al.
VIP modulation of immune cell functions
Adv. Neuroimmunol.
(1996) - et al.
Characterization of gene expression of VIP and VIP1-receptor in rat peritoneal lymphocytes and macrophages
Regul. Pept.
(1996) - et al.
Vasoactive intestinal peptide and pituitary adenylate cyclase activating polypeptide inhibit TNFα transcriptional activation by regulating NFkB and CREB/c-Jun
J. Biol. Chem.
(1998) - et al.
The vasoactive intestinal peptide analogue RO25–1553 inhibits the production of TNF and IL-12 by LPS-activated monocytes
Immunol. Lett.
(1998) Regulatory effects of vasoactive intestinal peptide on cytokine production in central and peripheral lymphoid organs
Adv. Neuroimmunol.
(1996)- et al.
Fragments of the pituitary adenylate cyclase-activating polypeptide discriminate between type I and II recombinant receptors
Eur. J. Pharmacol.
(1995) - et al.
The C-terminus ends of secretin and VIP interact with the N-terminal domains of their receptors
Peptides
(1996) - et al.
Development of high affinity selective VIP1 receptor agonists
Peptides
(1997)
In vitro properties of a high affinity selective antagonist of the VIP1 receptor
Peptides
Immunosuppresive retroviral peptides: cAMP and cytokine patterns
Immunol. Today
Differential effects of gastrin-releasing peptide, neuropeptide Y, somatostatin and vasoactive intestinal peptide on interleukin-1 beta, interleukin-6, and tumor necrosis factor alpha production by whole blood cells from healthy young and old subjects
J. Neuroimmunol.
Prostaglandin E2 regulates macrophage-derived tumor necrosis factor gene expression
J. Biol. Chem.
Expression of vasoactive intestinal peptide in lymphocytes: a possible endogenous role in the regulation of the immune system
Adv. Neuroimmunol.
Identification and characterization of a novel Ets-2-related nuclear complex implicated in the activation of the human interleukin-12 p40 gene promoter
J. Biol. Chem.
IL-12 deficient mice are defective in IFNγ production and type 1 cytokine responses
Immunity
Regulation of VIP production and secretion by murine lymphocytes
J. Neuroimmunol.
Somatostatin and vasoactive intestinal peptide reduce interferon gamma production by human peripheral blood mononuclear cells
Immunobiology
Structure-activity studies of vasoactive intestinal polypeptide
J. Biol. Chem.
Functional characterization and mRNA expression of pituitary adenylate cyclase activating polypeptide (PACAP) type I receptor in rat peritoneal macrophages
Biochim. Biophys. Acta
Vasoactive intestinal peptide inhibits IL-12 and nitric oxide production in murine macrophages
J. Neuroimmunol.
Vasoactive intestinal peptide inhibits interleukin (IL)-2 and IL-4 production in murine thymocytes activated via TCR/CD3 complex
J. Neuroimmunol.
Production of natural killer cell stimulatory factor (NKSF/IL-12) by peripheral blood mononuclear cells
J. Exp. Med.
Interleukin-10 inhibits human lymphocyte IFN-γ production by suppressing natural killer cell stimulatory factor/interleukin-12 synthesis in accessory cells
J. Exp. Med.
Antigen-driven but not lipopolysaccharide-driven IL-12 production in macrophages requires triggering of CD40
J. Immunol.
Vasoactive intestinal peptide and pituitary adenylate cyclase activating polypeptide inhibit endotoxin-induced TNFα production by macrophages: in vitro and in vivo studies
J. Immunol.
VIP and PACAP protect mice from lethal endotoxemia through the inhibition of TNFα and IL-6
J. Immunol.
Vasoactive intestinal peptide and pituitary adenylate cyclase activating polypeptide enhance IL-10 production by macrophages: in vitro and in vivo studies
J. Immunol.
Evidence for IFN-gamma as a mediator of the lethality of endotoxin and tumor necrosis factor-alpha
J. Immunol.
Interleukin-10 inhibits cytokine production by activated macrophages
J. Immunol.
Early interleukin 12 production by macrophages in response to mycobacterial infection depends on interferon gamma and tumor necrosis factor alpha
J. Exp. Med.
Pituitary adenylate cyclase activating polypeptide (PACAP) immunolocalization in lymphoid tissues of the rat
Cell Tissue Res.
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