![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
INFLAMMATION AND IMMUNOPHARMACOLOGY
Depaertment of Pediatrics, University of Iowa, Iowa City, Iowa (M.A.S., M.S.O., M.O.C., M.L.-M.); and Departments of Medicine and Microbiology-Immunology, University of California, San Francisco, California (E.J.G.)
Received March 7, 2003; accepted May 9, 2003.
 |
Abstract |
|---|
 Top Abstract Materials and MethodsResultsDiscussionReferences |
|---|
; Goetzl et al., 1988; O'Dorisio et al., 1980), whereas monocytes and lymphocytes express high-affinity receptors for these and other peptides (Danek et al., 1983; Ottaway et al., 1983; Scicchitano et al., 1987; O'Dorisio et al., 1989; Sreedharan et al., 1989). The structure and processing of prepro-VIP seems to differ in leukocytes compared with nerve cells; leukocytes produce and secrete both truncated and N-terminally extended peptides such as VIP10–28 and VIP–6–28 (Hayakawa et al., 1984; Goetzl et al., 1988). Several VIP fragments, of which VIP4–28 is the most prominent, are generated from VIP by protease activity at the surface of lymphocytes (Goetzl et al., 1988). These peptides may be released into tissue fluids at nanomolar concentrations and therefore potentially exert significant immunoregulatory and other physiological effects. This study was designed to compare VPAC1 and VPAC2 recognition of VIP and several VIP variant peptides (Goetzl et al., 1988). Human cell lines that express only a single VIP receptor were identified by real-time RT-PCR; the relative affinities of these peptides for the two VIP receptors, VPAC1 in HT-29 colonic epithelial cells and VPAC2 in lymphoblastoid cells, were determined by competitive binding. Further experiments then examined the ability of VIP and VIP-related peptides to activate the cAMP signal transduction pathway in each cell line alone or in the presence of VIP. |
Materials and Methods |
|---|
|
TopAbstractMaterials and MethodsResultsDiscussionReferences |
|---|
Real-Time RT-PCR. Real-Time RT-PCR was performed using the 5'-3' nuclease activity of Taq polymerase to allow direct detection of the product by the release of a fluorescent reporter dye from a specific fluorescent-labeled probe during the PCR reaction. The probe consists of an oligonucleotide with a 5'-reporter dye (6-carboxyfluorescein) or VIC dye and 3'-quencher dye 6-carboxytetramethylrhodamine (TAMRA) (Applied Biosystems, Foster City, CA). Specific primers were designed for real-time RT-PCR of VPAC1, 5'-ACA AGG CAG CGA GTT TGG AT-3' and 5'-GTG CAG TGG AGC TTC CTG AAC-3'; VPAC2, 5'-CGT GAA CAG CAT TCA CCC AGA AT-3 and 5'-CGT GAC GGT CTC TCC CAC AT-3'; and rRNA, 5'CGGCTACCACATCCAAGGAA-3' and 5'-GCTGGAATTACCGCGGCT3'. The probes for VPAC1, CCACCCTTCTGGTCGCCACAGCTATTAMRA and VPAC2, AACACAAAGCCTGCAGTGGCGTCTG-TAMRA were labeled with 6-carboxyfluorescein. The rRNA probe TGCTGGCACCAGACTTGCCCTC-TAMRA was labeled with VIC, which has a different spectrum than the reporter dye of the VPAC1 and VPAC2 probes. The rRNA was used to ensure quality of RNA preparation, to account for efficiency of the reverse transcription, and to control for any loading variation of the initial cDNA amount. One standard curve for the target gene (VPAC1 or VPAC2), and one standard curve for the rRNA gene were generated for quantification. The rRNA standard curve was generated with known (picogram) amounts of a cloned rRNA gene (Lara-Marquez et al., 2001) to determine the relative expression of rRNA in each sample. Serial dilutions of linearized plasmids containing the human VPAC1 or VPAC2 gene were used to construct a standard curve of copy number versus threshold cycle (CT). The actual number of copies of each target gene is thus extrapolated from each standard curve. VPAC1 and VPAC2 are measured as copy number and rRNA as picograms. The copy numbers are normalized against 100 pg of rRNA. The results are expressed as copy number per 100 pg of rRNA using the following formula: copy number/100 pg of rRNA = copy number of VPAC1 or VPAC2 x 100/pg of rRNA of each individual sample.
Reactions were performed in a MicroAmp Optical 96-well reaction plate (Applied Biosystems) using 2.5 µl of cDNA clone or unknown samples, 12.5 µl of 2x Master Mix [8% glycerol, 1x TaqMan buffer A, 200 µM dATP, 200 µM dCTP, 200 µM dCTP, 200 µM dGTP, 400 µM dUTP, 0.05 U/µl AmpErase uracil N-glycosylase, 5 mM MgCl2, and 0.01 U/µl Gold amplitaq DNA polymerase (Applied Biosystems)], forward/reverse primer (900 nM) and labeled probe for the target gene (200 nM) (VPAC1 or VPAC2), and forward/reverse primer (50 nM) and labeled probe (50 nM) for the housekeeper gene (rRNA). The final volume of the PCR reaction was brought up to 25 µl. Samples of the plasmid clone only have the target gene set of primers and probe. Amplification conditions are 2 min at 50°C (to activate Amperase to prevent PCR carryover) 10 min at 95°C (to activate Gold amplitaq) for the first cycle, followed by 40 cycles with a denaturing step of 15 s at 95°C and an anneal/extension step of 1 min at 60°C. All reactions were performed in the 7700 Sequence Detector thermocycler linked to a Macintosh computer using the sequence detector software to run the PCR reaction.
Enriched Plasma Membrane Preparations. Membranes were prepared as we have described previously (O'Dorisio et al., 1988). Cells were suspended in buffer A (20 mM HEPES, 2 mM MgCl2, 5 mM EDTA, 1 mM 2-mercaptoethanol, 150 mM NaCl2, and 50 µg/ml phenylmethylsulfonyl flouride, pH 7.4) at a concentration of 5 x 106 cells/ml buffer. Cells were subjected to ultrasonic disruption by Polytron (Brinkmann Instruments, Westbury, NY) for 30 s followed by centrifugation at 750g for 5 min. The pellet was resuspended in one-half the original volume of buffer A and disrupted by Polytron for an additional 30 s. After a second 750g spin, the two supernatant fractions were combined and centrifuged for 20 min at 48,000g. The resulting particulate fraction was washed in the original volume of buffer A and centrifuged 48,000g for 20 min. The particulate membrane fraction was resuspended in buffer A and stored at –80° until use.
Membrane Binding. Binding studies were performed as we have described previously (O'Dorisio et al., 1988). Competition experiments for estimation of receptor number (Bmax) and affinity (KD) were performed using 100 µg of membrane protein in buffer A containing 50 pM 125I-VIP (35,000–50,000 cpm) and increasing concentrations of unlabeled VIP or homologous peptide in a total volume of 0.5 ml. 125I-VIP (specific activity 2200 Ci/mmol) was purchased from PerkinElmer Life Sciences (Boston, MA), and synthetic VIP was purchased from Bachem (Torrance, CA). Reactions were started by the addition of membrane and the binding reaction continued under steady-state conditions for 30 min at 17°C in a shaking controlled temperature water bath. The reaction was stopped by filtering triplicate 0.15-ml aliquots of binding mixture over GF/C filters (Whatman, Maidstone, UK) presoaked in 0.3% polyethylenimine followed by triplicate washes of buffer A containing 0.2% bovine serum albumin. Radioactivity bound to filters was quantified in a Beckman Gamma 5500. Triplicates of both total and nonspecific binding were performed for every experiment. Specific binding was calculated as the difference between the means of determinations of total binding and binding in the presence of 1 µM unlabeled VIP. For both cell lines, specific binding was linear over the range of 25 to 350 µg of protein, total binding constituted 60 to 80% of added 125I-VIP, and specific binding was >75% of total binding. Analysis of the data were performed using the LIGAND program (McPherson, 1985).
Quantification of Intracellular Cyclic Nucleotides. HT-29 monolayers in 24-well plates or Molt-4b cells in suspension cultures were gently washed three times with Seligman's balanced salt solution. Triplicate wells or tubes of cells were incubated with a final volume of 1.0 ml of RPMI 1640 medium at 37°C for 5 min in the absence or presence of peptide, forskolin, or prostaglandin E2. Experimental drugs were dissolved in media without additives. Reactions were terminated by the addition of one-third volume of 30% trichloroacetic acid (TCA). Plates were scraped immediately; cells were transferred to high-speed centrifuge tubes. Cell suspensions were subjected to ultrasonic disruption and centrifuged at 10,000g for 10 min at 4°C. TCA was removed from supernatants by ether extraction; cyclic AMP was succinylated and quantified by radioimmunoassay as described previously by our laboratory (Chen et al., 1993).
Concentration Dependence of Antagonism by VIP4–28. cAMP dose-response curves for VIP were generated in Molt-4b cells in the presence of various concentrations of VIP4–28 (0, 0.1 nM, 10 nM, and 1 µM), which were added simultaneously. The data were then compiled using GraphPad software (GraphPad Software, Inc., San Diego, CA) for analysis of dose-response curves in the presence of antagonists, a nonlinear analysis based on Schild plot technique. Simultaneous addition of the two peptides may not provide sufficient time for maximum binding of VIP4–28 (Sjoberg et al., 1987).
Peptide Synthesis. All peptides were synthesized by automated solid phase techniques in a three-vessel model 430A system (Applied Biosystems) as described previously (Goetzl et al., 1988). After cleavage from the resin with hydrofluoric acid, the peptides were purified by high-performance liquid chromatography (HPLC) on a 2 x 25 cm octadecylsilane column in a model 1406 A system using a solvent program of 30 min of 0.1% trifluoracetic acid in water at 8 ml/min and then a 90-min gradient of 65% acetonitrile/35% 0.1% trifluoracetic acid. Identity of each peptide (Fig. 1) was evaluated by complete amino acid sequence with gas-phase Edman method in a model 470A system equipped with on line narrow bore HPLC analysis (Beckman model 120A) and automated data integration (model 900A) for quantification of parathyroid hormone amino acids. All experiments using VIP4–28 were also performed with peptide purchased from Bachem.
|
|
Results |
|---|
|
TopAbstractMaterials and MethodsResultsDiscussionReferences |
|---|
|
High-Affinity Binding of VIP and VIP4–28 to VPAC1 and VPAC2. Competitive binding studies were performed on plasma membranes harvested from the HT-29 colonic epithelial cell line. VIP4–28 was equally as effective as VIP as a competitive inhibitor of 125I-VIP binding (Fig. 3A). These experiments revealed apparent identity in the affinity of receptors recognized by VIP and VIP4–28 with KD = 1.6 and 1.7 nM, respectively (Table 1). Using the conversion factor of 1 µg of membrane protein/2.3 ± 0.4 x 106 HT-29 cells, the Bmax of 0.7 nM extrapolates to 85,000 VPAC1 receptors/cell.
|
|
Molt-4b lymphoblasts exhibit a single class of high affinity VIP binding sites with a KD = 1.7 nM for both VIP and and VIP4–28 (Fig. 3B). Analysis of the number of binding sites for each peptide using the LIGAND program revealed apparent identity between VIP and VIP4–28 (Bmax = 0.7 ± 0.1 and 0.8 ± 0.6 nM, respectively), suggesting that the two peptides bind to the same receptor (Table 1). Using this method of membrane preparation, 1 µg of membrane protein corresponds to 9.5 ± 2.9 x 106 Molt-4b cells. The Bmax of 0.7 nM represents an estimated 20,000 high-affinity VPAC2 binding sites per cell, in good agreement with our previous estimate of 15,000 sites/cell (Beed et al., 1983).
Binding of VIP–6–28 and VIP10–28 to VPAC1 and VPAC2. The peptides VIP–6–28 and VIP10–28, were less effective inhibitors of 125I-VIP binding in both cell lines (Fig. 3, A and B). VIP-6–28 bound to HT-29 colonic cells and to Molt-4b lymphoblasts with intermediate affinities of 7.2 and 8.4 nM, respectively. VIP10–28 demonstrated the lowest affinity for VPAC1 and VPAC2 with KD values of 74 and 67 nM in HT-29 cells and Molt-4b cells, respectively (Table 1). Thus, the three natural variants of VIP demonstrated competitive inhibition of 125I-VIP binding with the rank order of potency VIP4–28 = VIP > VIP–6–28 >> VIP10–28.
VIP4–28 Activation of Signal Transduction via VPAC1. The agonist activities of the VIP variant peptides were compared in cyclic nucleotide experiments (Table 2). The basal cAMP level is higher in the Molt-4b lymphoblastic cell line than in HT-29 colonic cells. However, prostaglandin E2 induces 16- to 22-fold increases in cAMP in both cell lines and forskolin induces a 150-fold increase in cAMP in both cell lines. In contrast, VIP is a much more effective agonist in HT-29 cells than in Molt-4b cells, raising cAMP levels in HT-29 cells 225-fold over basal in 5 min compared with a 14-fold increase in Molt-4b cells. VIP4–28 induces >400-fold increase in cAMP levels in HT-29 cells, but has no agonist activity in Molt-4b lymphoblasts. VIP-6–28 has agonist activity similar to VIP in both cell types, whereas VIP10–28 has no agonist activity in either HT-29 colonic cells or in Molt-4b lymphoblasts.
|
VIP4–28 Is VPAC1 Agonist and VPAC2 Antagonist. Figure 4 demonstrates comparative dose-response curves for VIP4–28 in HT-29 colonic cells and Molt-4b lymphoblasts. The basal level of cAMP in HT-29 cells is 0.9 ± 0.2 pmol of cAMP/106 cells and cAMP is increased to 18.4 ± 1.7 pmol/106 cells in the presence of 10 nM VIP4–28 (p < 0.01). VIP4–28 also induces significant increases in cAMP levels in HT-29 cells at 100 nM and 1 µM concentrations (p < 0.01), whereas no significant increase in cAMP levels is observed in Molt-4b cells at any concentration tested over the range 0.1 nM to 1 µM VIP4–28.
|
The dose-response curve for VIP-mediated generation of cAMP via VPAC1 in HT-29 colon carcinoma cells is shown in Fig. 5. VIP is a more efficient agonist than VIP4–28; 10 nM VIP induces maximal cAMP accumulation compared with 1 µM VIP4–28 (Fig. 5 versus Fig. 4). Also shown in Fig. 5 is the effect of 1 µM VIP4–28 together with increasing concentrations of VIP. VIP and VIP4–28 together have the same maximal cAMP stimulation as either peptide alone, suggesting that both peptides use the same receptor in HT-29 cells.
|
Dose-response curves for VIP-mediated cAMP generation in Molt-4b lymphoblasts are shown in Fig. 6. The maximum accumulation of cAMP via VPAC2 is observed at 10 nM VIP. This effect is inhibited 95% by 1 µM VIP4–28 (p < 0.01). Similarly, VIP4–28 inhibits the effects of 0.1 µM VIP by 89% (p < 0.01), but does not significantly inhibit the effect of 1 µM VIP (p > 0.1). The right shift of the VIP dose-response curve in the presence of 1 µM VIP4–28, and the fact that VIP4–28 does not effectively antagonize the action of an equimolar concentration of VIP, support the hypothesis that these two peptides compete for the same high-affinity receptor in Molt-4b lymphoblasts.
|
VIP 4–28 Antagonism of VPAC2 Is Dose-Dependent. Dose-response curves for VIP interaction with VPAC2 were generated in Molt-4b cells in the presence of various concentrations of VIP4–28. Figure 7 demonstrates VIP dose-response curves in the presence of 0.1 nM, 10 nM, and 1 µM VIP4–28. Although VIP was able to induce full agonist activation of VPAC2 in the presence of the putative antagonist VIP4–28, the slope of the resulting Schild plot is 0.59 ± 0.34.
|
VPAC1 Agonist Activity of VIP4–28 Is Not Inactivated by Lymphoblasts. One possible explanation for the paradoxical effects of VIP4–28 in HT-29 cells and Molt-4b cells would be proteolytic degradation of the peptide by lymphoblasts. This possibility was tested in three sets of experiments: 1) addition of protease inhibitors to Molt-4b cells during VIP4–28 exposure; 2) incubation of VIP4–28 with Molt-4b cells before addition to HT-29 cells; and 3) extraction and HPLC purification of VIP4–28 and possible degradation products after incubation with Molt-4b cells.
Addition of protease inhibitors did not enhance the ability of VIP4–28 to induce cAMP generation in Molt-4b lymphoblasts (Table 3). To further test whether Molt-4b lymphocytes hydrolyze VIP4–28 to a peptide fragment with antagonist activity in both HT-29 and Molt-4b cells, VIP4–28 was added to Molt-4b lymphoblast cultures at a concentration of 1 µM. After 5 min, the medium (containing VIP4–28 and any hydrolyzed peptides) was incubated with HT-29 cells. As can be seen in Table 4, VIP4–28 had no agonist activity in Molt-4b lymphoblasts, but when transferred to colonic cells, this same media (containing VIP4–28 and/or its degradation products) demonstrated potent agonist activity in HT-29 cells. Molt-4b cells and HT-29 cells that had been incubated with 1 µM VIP4–28 for 5 min at 37°C were extracted in ethanol/acetic acid and the peptides analyzed by HPLC. VIP4–28 was the only peptide identified in the extract.
|
|
|
Discussion |
|---|
|
TopAbstractMaterials and MethodsResultsDiscussionReferences |
|---|
) and the immunoglobulin receptor (Torigoe et al., 1998). These antagonists are pseudoreceptors or truncated receptors. Analogs of a ligand can also function as antagonists; 
-blockers that antagonize action of endogenous -adrenergic receptor ligands are among the most well known antagonists in this category (Strader et al., 1989). Endogenous peptides are physiological antagonists of the IL-1 and IL-7 receptors (Carter et al., 1990; Granowitz et al., 1991).
Several VIP analogs have been designed as VIP receptor antagonists. These peptide ligands include VIP10–28 (Turner et al., 1986), (N-Ac-Tyr1,D-Phe2)-GRF(1–29)-NH2 (Waelbroeck et al., 1985), and neurotensin6–11-VIP7–28 (Gozes et al., 1996). Although VIP demonstrates high-affinity binding with affinity constants in the subnanomolar range, the above-named antagonists all have dissociation constants in the micromolar range. We demonstrate that VIP4–28 has affinity equal to VIP, has potent agonist activity at VPAC1, and has potent antagonist activity at VPAC2. The first three amino acids in VIP (H, S, and D), seem to be important for stimulation of adenylate cyclase via VPAC2 as suggested by the ability of both VIP and VIP-6–28, but not VIP4–28 or VIP10–28 to induce cAMP accumulation in Molt-4b cells. This is consistent with the early observations of Mutt (1982) that aspartic acid in position 3 at the N-terminal end of VIP and secretin is important in cAMP generation. VIP4–28 thus is unique in several respects: 1) it is an endogenous peptide generated by lymphocyte proteolysis of VIP; 2) it binds with high affinity to both VPAC1 and VPAC2; and 3) it has VPAC1 agonist activity and VPAC2 antagonist activity. These observations all suggest a role for VIP4–28 in vivo.
Previous studies have established the presence of high-affinity VIP receptors on human intestinal epithelial cells where VIP mediates water and electrolyte secretion as well as on human T and B lymphocytes (Danek et al., 1983; O'Dorisio et al., 1989). In the immune system, VIP seems to modulate lymphocyte trafficking, T cell proliferation, and B cell synthesis of IgA (Lara-Marquez et al., 2001). The present studies used two human cell lines as in vitro models of intestinal epithelial cells and immune cells. The Molt-4b cell line is derived from human leukemia cells. HT-29 is a colonic epithelial cell line established from a human colon carcinoma. Previous studies from our laboratory have demonstrated that VIP interacts with high-affinity receptors to stimulate adenylate cyclase, activate protein kinase A, and induce phosphorylation of an identical 38-kDa protein in both cell lines (O'Dorisio and Campolito, 1989). The results presented here suggest that functional differences exist between the VPAC1 receptor expressed on HT-29 cells and the VPAC2 receptor expressed on Molt-4b lymphoblasts. Although the lymphoblastic and colonic cell receptors seem to bind VIP with equal affinity and with similar numbers of receptors per milligram of membrane protein, the HT-29 receptor complex seems to transduce a signal from VIP and VIP4–28 to adenylate cyclase more efficiently.
Although the number of receptors per milligram of membrane protein is quite similar in HT-29 cells and Molt-4b lymphoblasts, the number of VIP receptors per cell is 4-fold greater in HT-29 cells; this may account partially for the higher stimulation index for VIP in HT-29 cells. However, the finding that VIP4–28 stimulates cAMP generation in HT-29 cells and inhibits VIP-mediated cAMP accumulation in Molt-4b lymphoblasts demonstrates that VPAC1 and VPAC2 are functionally quite different receptors.
The 
and subtypes of adrenergic receptors were identified by their similar affinities for epinephrine; these subtypes can, however, be differentiated by selective drugs and by their second messenger generation in response to epinephrine. These receptors are now known to be the products of separate but homologous genes. VPAC1 and VPAC2 are products of distinct genes (Adamou et al., 1995). The VPAC1 receptor has been cloned from HT-29 colon carcinoma cells and shown to be a 42-kDa protein (Sreedharan et al., 1991). VPAC2 was cloned from a human placental library (Adamou et al., 1995). Cross-linking studies in our laboratory have demonstrated a 47-kDa receptor protein in both HT-29 and Molt-4b cells (Wood and O'Dorisio, 1985). The results of the present study suggest that VPAC1 on HT-29 colonic epithelial cells and VPAC2 on Molt-4b lymphoblasts can be functionally differentiated by their response to VIP4–28.
This may be of functional significance in the intestine wherein VIP modulates water and electrolyte secretion via stimulation of adenylate cyclase in intestinal epithelial cells (Amiranoff et al., 1978). VIP also seems to modulate secretion of IgA, the major antibody in intestinal secretions (Stanisz et al., 1986). In the immune system, VIP synthesized and released from eosinophils modulates cytokine production (Weinstock, 1991). VIP down-regulates IL-2, IL-4 (Iwamoto et al., 1992), IL-10 (Martinez et al., 1998), and tumor necrosis factor- (Dewit et al., 1998; Jabrane-Ferrat et al., 1999) and up-regulates antigen-induced interferon-
(Jabrane-Ferrat et al., 1999) as well as IL-5 (Mathew et al., 1992). We have shown that VPAC1 is down-regulated and VPAC2 is upregulated during activation of CD4+ T cells (Lara-Marquez et al., 2001). VIP and/or similar peptides regulate circadian rhythms; mice lacking the VPAC2 gene fail to adapt to changes in light cycles (Harmar et al., 2002).
The observations reported here suggest that VIP released from nerve endings or eosinophils in the gut can differentially activate enterocytes and lymphocytes. In lymphocytes, VIP seems to be hydrolyzed to VIP4–28 by an unknown mechanism (Goetzl et al., 1989). We now demonstrate that the peptide fragment, VIP4–28, stimulates adenylate cyclase in enterocytes via VPAC1 and inhibits VPAC2-mediated stimulation of adenylate cyclase. Thus, the presence of an antagonist for VPAC2 may have functional significance in the intestine wherein VIP modulates water and electrolytes (Barbezat and Grossman, 1971) in enterocytes expressing VPAC1 (Amiranoff et al., 1978) and also comes in contact with intraepithelial lymphocytes expressing VPAC2.
VPAC1 and VPAC2 are the only known receptors to which VIP binds with high affinity. Although VIP binds to the pituitary adenylate cyclase activating peptide receptor PAC1, VIP has both lower affinity and lower potency as a PAC1 ligand than does pituitary adenylate cyclase activating peptide (Sano et al., 2002). For this reason, and also because we have no access to a PAC1-expressing human cell line lacking VPAC1 and VPAC2 expression, these studies have not examined the agonist and antagonist activity of VIP, VIP-6–28, VIP4–28, and VIP10–28 at the PAC1 binding site. If VIP4–28 proves to be a potent VPAC1 agonist/VPAC2 antagonist in vivo, its agonist/antagonist activity at the PAC1 binding site would be warranted.
In summary, VIP4–28, a proteolytic product of the major secreted peptide VIP1–28, is a potent agonist for VPAC1 and a potent antagonist for VPAC2. This identification of an endogenous VPAC2 antagonist has important implications for selective regulation of intestinal secretion and mucosal immune function.
|
Acknowledgements |
|---|
|
Footnotes |
|---|
ABBREVIATIONS: VIP, vasoactive intestinal peptide; RT-PCR, reverse transcriptase-polymerase chain reaction; PCR, polymerase chain reaction; TAMRA, 6-carboxytetramethylrhodamine; TCA, trichloroacetic acid; HPLC, high-pressure liquid chromatography; PAC1, pituitary adenylate cyclase-activating peptide receptor 1.
Address correspondence to: Dr. M. Sue O'Dorisio, Department of Pediatrics, 2520 JCP, 200 Hawkins Dr., Iowa City, IA 52242. E-mail: sue-odorisio{at}uiowa.edu
|
References |
|---|
|
TopAbstractMaterials and MethodsResultsDiscussionReferences |
|---|
Adamou JE, Aiyar N, Van Horn S, and Elshourbagy NA (1995) Cloning and functional characterization of the human vasoactive intestinal peptide (VIP)-2 receptor. Biochem Biophys Res Commun 209: 385–392.[CrossRef][Medline]
Amiranoff B, Laburthe M, Dupont C, and Rosselin G (1978) Characterization of a vasoactive intestinal peptide-sensitive adenylate cyclase in rat intestinal epithelial cell membranes. Biochim Biophys Acta 544: 474–481.[Medline]
Barbezat GO and Grossman MI (1971) Intestinal secretion: stimulation by peptides. Science (Wash DC) 174: 422–424.
Beed EA, O'Dorisio MS, O'Dorisio TM, and Gaginella TS (1983) Demonstration of a functional receptor for vasoactive intestinal polypeptide on Molt 4b T lymphoblasts. Regul Pept 6: 1–12.[CrossRef][Medline]
Carter DB, Deibel MR Jr, Dunn CJ, Tomich CS, Laborde AL, Slightom JL, Berger AE, Bienkowski MJ, Sun FF, and McEwan RN (1990) Purification, cloning, expression and biological characterization of an interleukin-1 receptor antagonist protein. Nature (Lond) 344: 633–638.[CrossRef][Medline]
Chan AM, Rubin JS, Bottaro DP, Hirschfield DW, Chedid M, and Aaronson SA (1991) Identification of a competitive HGF antagonist encoded by an alternative transcript. Science (Wash DC) 254: 1382–1385.
Chen F, O'Dorisio MS, Hermann G, Hayes J, Malarkey WB, and O'Dorisio TM (1993) Mechanisms of action of long-acting analogs of somatostatin. Regul Pept 44: 285–295.[CrossRef][Medline]
Danek A, O'Dorisio MS, O'Dorisio TM, and George JM (1983) Specific binding sites for vasoactive intestinal polypeptide on nonadherent peripheral blood lymphocytes. J Immunol 131: 1173–1177.[Abstract]
Dewit D, Gourlet P, Amraoui Z, Vertongen P, Willems F, Robberecht P, and Goldman M (1998) The vasoactive intestinal peptide analogue RO25-1553 inhibits the production of TNF and IL-12 by LPS-activated monocytes. Immunol Lett 60: 57–60.[CrossRef][Medline]
Goetzl EJ, Chernov-Rogan T, Cooke MP, Renold F, and Payan DG (1985) Endogenous somatostatin-like peptides of rat basophilic leukemia cells. J Immunol 135: 2707–2712.[Abstract]
Goetzl EJ, Kodama KT, Turck CW, Schiogolev SA, and Sreedharan SP (1989) Unique pattern of cleavage of vasoactive intestinal peptide by human lymphocytes. Immunology 66: 554–558.[Medline]
Goetzl EJ, Sreedharan SP, and Turck CW (1988) Structurally distinctive vasoactive intestinal peptides from rat basophilic leukemia cells. J Biol Chem 263: 9083–9086.
Gozes I, Lilling G, Davidson A, Bardea A, Reshef A, Glazer R, Zamostiano R, Ashur-Fabian O, Ticher A, Ashkenazi IE, et al. (1996) Development of VIP agonists and antagonists with tissue and receptor specificity: effects on behavioral maturation, sexual function and the biologic clock. Ann NY Acad Sci 805: 159–169.[Medline]
Granowitz EV, Clark BD, Mancilla J, and Dinarello CA (1991) Interleukin-1 receptor antagonist competitively inhibits the binding of interleukin-1 to the type II inter-leukin-1 receptor. J Biol Chem 266: 14147–14150.
Harmar AJ, Marston HM, Shen S, Spratt C, West KM, Sheward WJ, Morrison CF, Dorin JR, Piggins HD, Reubi JC, et al. (2002) The VPAC(2) receptor is essential for circadian function in the mouse suprachiasmatic nuclei. Cell 109: 497–508.[CrossRef][Medline]
Hayakawa Y, Obata K, Itoh N, Yanaihara N, and Okamoto H (1984) Cyclic AMP regulation of pro-vasoactive intestinal polypeptide/PHM-27 synthesis in human neuroblastoma cells. J Biol Chem 259: 9207–9211.
Iwamoto I, Tomoe S, Tomioka H, and Yoshida S (1992) Substance P-induced granulocyte infiltration in mouse skin: the mast cell-dependent granulocyte infiltration by the N-terminal peptide is enhanced by the activation of vascular endothelial cells by the C-terminal peptide. Clin Exp Immunol 87: 203–207.[Medline]
Jabrane-Ferrat N, Bloom D, Wu A, Li L, Lo D, Sreedharan SP, Turck CW, and Goetzl AE (1999) Enhancement by vasoactive intestinal peptide of gamma-interferon production by antigen-stimulated type 1 helper T cells. FASEB J 13: 347–353.
Lara-Marquez M, O'Dorisio M, O'Dorisio T, Shah M, and Karacay B (2001) Selective gene expression and activation-dependent regulation of vasoactive intestinal peptide receptor type 1 and type 2 in human T cells. J Immunol 166: 2522–2530.
Martinez C, Delgado M, Pozo D, Leceta J, Calvo JR, Ganea D, and Gomariz RP (1998) Role of Ca2+ influx in bombesin-induced mitogenesis in Swiss 3T3 fibroblasts. J Neuroimmunol 85: 155–167.[CrossRef][Medline]
Mathew RC, Cook GA, Blum AM, Metwali A, Felman R, and Weinstock JV (1992) Vasoactive intestinal peptide stimulates T lymphocytes to release IL-5 in murine schistosomiasis mansoni infection. J Immunol 148: 3572–3577.[Abstract]
McPherson GA (1985) Analysis of radioligand binding experiments. A collection of computer programs for the IBM PC. J Pharmacol Methods 14: 213–228.[CrossRef][Medline]
Mutt V (1982) Isolation and structure of vasoactive intestinal polypeptide from various species, in Vasoactive Intestinal Peptide: Advances in Peptide Hormone Research Series (Said SI ed) pp 1–10, Raven Press, NY
O'Dorisio MS and Campolito LB (1989) Comparison of vasoactive intestinal peptidemediated protein phosphorylation in human lymphoblasts and colonic epithelial cells. Mol Immunol 26: 583–590.[CrossRef][Medline]
O'Dorisio MS, O'Dorisio TM, Cataland S, and Balcerzak SP (1980) Vasoactive intestinal polypeptide as a biochemical marker for polymorphonuclear leukocytes. J Lab Clin Med 96: 666–672.[Medline]
O'Dorisio MS, Shannon BT, Fleshman DJ, and Campolito LB (1989) Identification of high affinity receptors for vasoactive intestinal peptide on human lymphocytes of B cell lineage. J Immunol 142: 3533–3536.[Abstract]
O'Dorisio MS, Vasiloff J, Campolito LB, Beattie MS, and Bresnahan JC (1988) Characterization of the VIP receptor in rat frontal cortex. Neuroscience Res Comm 2: 19–28.
Ottaway CA, Bernaerts C, Chan B, and Greenberg GR (1983) Specific binding of vasoactive intestinal peptide to human circulating mononuclear cells. Can J Physiol Pharmacol 61: 664–671.[Medline]
Sano H, Miyata A, Horio T, Nishikimi T, Matsuo H, and Kangawa K (2002) The effect of pituitary adenylate cyclase activating polypeptide on cultured rat cardiocytes as a cardioprotective factor. Regul Pept 109: 107–113.[CrossRef][Medline]
Scicchitano R, Dazin P, Bienenstock J, Payan DG, and Stanisz AM (1987) Distribution of somatostatin receptors on murine spleen and Peyer's patch T and B lymphocytes. Brain Behav Immun 1: 173–184.[CrossRef][Medline]
Sjoberg T, Steen S, Skarby T, Norgren L, and Andersson KE (1987) Postjunctional alpha-adrenoceptors in human superficial epigastric arteries and veins. Pharmacol Toxicol 60: 43–50.[Medline]
Sreedharan SP, Kodama KT, Peterson KE, and Goetzl EJ (1989) Distinct subsets of somatostatin receptors on cultured human lymphocytes. J Biol Chem 264: 949–952.
Sreedharan SP, Robichon A, Peterson KE, and Goetzl EJ (1991) Cloning and expression of the human vasoactive intestinal peptide receptor [published erratum appears in Proc Natl Acad Sci USA 1993 Oct 1;90(19):9233]. Proc Natl Acad Sci USA 88: 4986–4990.
Stanisz AM, Befus D, and Bienenstock J (1986) Differential effects of vasoactive intestinal peptide, substance P, and somatostatin on immunoglobulin synthesis and proliferations by lymphocytes from Peyer's patches, mesenteric lymph nodes and spleen. J Immunol 136: 152–156.[Abstract]
Strader CD, Candelore MR, Hill WS, Dixon RA, and Sigal IS (1989) A single amino acid substitution in the beta-adrenergic receptor promotes partial agonist activity from antagonists. J Biol Chem 264: 16470–16477.
Torigoe C, Inman JK, and Metzger H (1998) An unusual mechanism for ligand antagonism. Science (Wash DC) 281: 568–572.
Turner JT, Jones SB, and Bylund DB (1986) A fragment of vasoactive intestinal peptide, VIP(10–28), is an antagonist of VIP in the colon carcinoma cell line, HT29. Peptides 7: 849–854.[CrossRef][Medline]
Waelbroeck M, Robberecht P, Coy DH, Camus JC, De Neef P, and Christophe J (1985) Interaction of growth hormone-releasing factor (GRF) and 14 GRF analogs with vasoactive intestinal peptide (VIP) receptors of rat pancreas. Discovery of (N-Ac-Tyr1, D-Phe2)-GRF(1–29)-NH2 as a VIP antagonist. Endocrinology 116: 2643–2649.[Abstract]
Weinstock JV (1991) Production of neuropeptides by inflammatory cells within the granulomas of murine schistosomiasis mansoni. Eur J Clin Investig 21: 145–153.[Medline]
Wood CL and O'Dorisio MS (1985) Covalent cross-linking of vasoactive intestinal polypeptide to its receptors on intact human lymphoblasts. J Biol Chem 260: 1243–1247.
This article has been cited by other articles:
|
|
 |
|
  D. Fabricius, M. S. O'Dorisio, S. Blackwell, and B. Jahrsdorfer Human Plasmacytoid Dendritic Cell Function: Inhibition of IFN-{alpha} Secretion and Modulation of Immune Phenotype by Vasoactive Intestinal Peptide J. Immunol., November 1, 2006; 177(9): 5920 - 5927. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Delgado, D. Pozo, and D. Ganea The Significance of Vasoactive Intestinal Peptide in Immunomodulation Pharmacol. Rev., June 1, 2004; 56(2): 249 - 290. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
 |
|
 |
 |
 |
