Peptides (v.26, #12)
IFC (editorial board) (CO2).
Histatin and lactoferrin derived peptides: Antimicrobial properties and effects on mammalian cells by Hein P. Stallmann; Chris Faber; Antonius L.J.J. Bronckers; Jolanda M.A. de Blieck-Hogervorst; Carlo P.J.M. Brouwer; Arie V. Nieuw Amerongen; Paul I.J.M. Wuisman (2355-2359).
In order to analyze the clinical potential of two antimicrobial peptides, human lactoferrin 1-11 (hLF1-11) and synthetic histatin analogue Dhvar-5, we measured the killing effect on bacteria, and the potential toxicity on erythrocytes and bone cells. The antimicrobial activity was determined in a killing assay on six strains, including methicillin resistant Staphylococcus Aureus. The effect on human erythrocytes and MC3T3 mouse bone cells was measured with a hemolysis assay and a viability assay, respectively. Both hLF1-11 and Dhvar-5 dose-dependently killed all bacterial strains, starting at concentrations of 6 μg/mL. hLF1-11 had no effect on mammalian cells at concentrations up to 400 μg/mL, but Dhvar-5 induced significant hemolysis (37% at 200 μg/mL) and bone cell death (70% at 400 μg/mL). This indicates that both peptides are able to kill various resistant and non-resistant bacteria, but Dhvar-5 may exert a cytotoxic effect on host cells at higher concentrations.
Keywords: Antimicrobial cationic peptide; Resistant bacterial strains; Mammalian cells; Cytotoxicity;
cDNA cloning of halocidin and a new antimicrobial peptide derived from the N-terminus of Ci-META4 by Woong Sik Jang; Chong Han Kim; Min Sook Kang; Hee Jeong Chae; Seok Min Son; Sook Jae Seo; In Hee Lee (2360-2367).
Halocidin is an antimicrobial peptide, which is isolated from hemocytes from the tunicate, Halocynthia aurantium. In this study, we cloned the full-length cDNA of halocidin from pharyngeal tissue, using a combination of RT-PCR and 5′-RACE-PCR. The observed cDNA structure indicated that halocidin is synthesized as a 10.37 kDa prepropeptide. Based on the cDNA structure and the known amino acid sequence of the mature peptide, it was concluded that the precursor of halocidin contains a 21-residue signal peptide, followed by the 18 residues of the mature peptide, and a 56-residue anionic C-terminal extension, which is removed later on in the process. The signal sequence of halocidin exhibited a high degree of similarity with the corresponding portion of the Ci-META4 protein, which had been previously discovered in the coelomic cells of another tunicate, Ciona intestinalis, and is considered to play a role in metamorphosis. However, in several respects, the cDNA structure of Ci-META4 suggested that it might constitute a precursor for an antimicrobial peptide. Thus, we prepared a synthetic peptide, which was comprised of 19 N-terminal amino acid residues in the predicted mature region of Ci-META4, and tested it with regard to its antimicrobial activity. As a result, we confirmed that the synthetic peptide exhibited potent antimicrobial activity against Gram (+) and (−) bacteria, while evidencing no hemolytic activity toward human erythrocytes.
Keywords: Halocidin; cDNA cloning; Antimicrobial peptide; Halocynthia aurantium; Tunicate; Ci-META4;
Tuning the biological properties of amphipathic α-helical antimicrobial peptides: Rational use of minimal amino acid substitutions by Igor Zelezetsky; Ulrike Pag; Hans-Georg Sahl; Alessandro Tossi (2368-2376).
In nature, alpha-helical antimicrobial peptides present the small and flexible residue glycine at positions 7 or 14 with a significant frequency. Based on the sequence of the non-proteinogenic alpha-helical model peptide P1(Aib7), with a potent, broad spectrum antimicrobial activity, six peptides were designed by effecting a single amino acid substitution to investigate how tuning the structural characteristics at position 7 could lead to optimization of selectivity without affecting antimicrobial activity against a broad panel of multidrug resistant bacterial and yeast indicator strains. The relationship between structural features (size/hydrophobicity of the side chain as well as conformation and flexibility) and biological activity, in terms of minimum inhibitory concentration, membrane permeabilization kinetics and lysis of red blood cells are discussed. On conversion of the peptide to proteinogenic residues, these principles allowed development of a potent antimicrobial peptide with a reduced cytotoxicity. However, while results suggest that both hydrophobicity of residue 7 and chain flexibility at this position can be modulated to improve selectivity, position 14 is less tolerant of substitutions.
Keywords: Antimicrobial peptide; Sequence template; Cytotoxicity; Alpha-helix;
Effects of the terminal charges in human neutrophil α-defensin 2 on its bactericidal and membrane activity by Cao Xie; Pengyun Zeng; Bryan Ericksen; Zhibin Wu; Wei-Yue Lu; Wuyuan Lu (2377-2383).
Human neutrophil α-defensin 2 (HNP2) was N-terminally acetylated and/or C-terminally amidated, resulting in three terminally modified analogs, Ac-HNP2, HNP2-NH2 and Ac-HNP2-NH2. We examined their bactericidal activity against E. coli and S. aureus and their ability to induce leakage from large unilamellar vesicles. Loss of the N-terminal positive charge was functionally deleterious, whereas removal of the C-terminal negative charge enhanced microbial killing and membrane permeabilization. Our findings validate the importance of electrostatic forces in defensin–microbe interactions and point to the bacterial cytoplasmic membrane as a target of HNP2 activity.
Keywords: Defensin; HNP; Large unilamellar vesicle; Liposome; Acetylation; Amidation;
Isarfelin, a peptide with antifungal and insecticidal activities from Isaria felina by Y.X. Guo; Q.H. Liu; T.B. Ng; H.X. Wang (2384-2391).
Isarfelin, a peptide with inhibitory activity on mycelial growth in Rhizoctonia solani and Sclerotinia sclerotiorum and insecticidal activity toward Leucania separata, was isolated from the mycelia of Isaria felina. The IC50 value of its antifungal activity against R. solani was 3.1 μg mL−1. However, it was devoid of activity toward several bacterial species including Bacillus subtilis, E. coli and Staphylococcus aureus. The isolation procedure involved ethanol extraction, adsorption on YPR II macropore adsorption resin, ethyl acetate extraction, petroleum ether precipitation and recrystallization from ethyl acetate.
Keywords: Isaria felina; Antifungal; Insecticidal;
An antifungal peptide from the coconut by H.X. Wang; T.B. Ng (2392-2396).
A chromatographic procedure consisting of ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-cellulose, and gel filtration by fast performance liquid chromatography on Supedex 75 was utilized to isolate a 10 kDa antifungal peptide from coconut flesh. The peptide was unadsorbed on DEAE-cellulose, but adsorbed on Affi-gel blue gel and CM-cellulose. It displayed antifungal activity against Fusarium oxysporum, Mycosphaerella arachidicola and Physalospora piricola. The IC50 values of its inhibitory activities on mycelial growth in M. arachidicola and HIV-1 reverse transcriptase activity were respectively 1.2 and 52.5 μM.
Keywords: Antifungal; Electrophoretic mobility; Mycelial colony;
An antifungal protein from flageolet beans by Lixin Xia; T.B. Ng (2397-2403).
A protein with antifungal and hemagglutinating activities was isolated from dried flageolet beans (Phaseolus vulgaris cv. ‘Flageolet Bean’). The protein was unadsorbed on DEAE-cellulose but adsorbed on Affi-gel blue gel and CM-cellulose. The protein demonstrated antifungal activity against Mycophaerella arachidicola with an IC50 of 9.8 μM, but was inactive toward Fusarium oxysporum and Botrytis cinerea. Its hemagglutinating activity could not be inhibited by a variety of the sugars tested. The activity was stable up to 60 °C. At 70 °C, 75% of the hemagglutinating activity remained while no activity was discernible at and above 100 °C. The hemagglutinating activity was stable in the presence of a variety of monovalent, divalent and trivalent chlorides, and also when the ambient pH changed from 3 to 12. It did not exert any mitogenic activity on mouse splenocytes in vitro. Neither did it inhibit HIV-1 reverse transcriptase. It inhibited [3H-methyl]-thymidine incorporation into leukemia L1210 cells with an IC50 of about 4 μM.
Keywords: Antifungal protein; Flageolet bean; Purification;
Molecular characterization of pheromone biosynthesis activating neuropeptide from the diamondback moth, Plutella xylostella (L.) by Dae-Weon Lee; Kyung Saeng Boo (2404-2411).
Pheromone biosynthesis activating neuropeptide (PBAN) produced in the subesophageal ganglion stimulates pheromone production in the pheromone gland. A cDNA isolated from female adult heads of the diamondback moth (Plutella xylostella (L.)) encodes 193 amino acids including PBAN, designated as Plx-PBAN, and four other neuropeptides (NPs): diapause hormone (DH) homologue, α-NP, β-NP and γ-NP. All of the peptides are amidated in their C-termini and shared a conserved motif, FXPR(or K)L structure, as reported from other PBAN cDNAs. Plx-PBAN consists of 30 amino acids, the shortest PBAN so far reported. Plx-PBAN exhibited below 50% homology, compared with other known PBANs. The Plx-DH homologue is structurally different from DH of Bombyx mori. The length of Plx-β-NP (16 amino acids) was the shortest and showed relatively low similarity, whereas γ-NP (10 amino acids in length) was the longest among examined γ-NPs. When female adults were injected with synthetic Plx-PBAN, pheromone production showed a maximal increase 1 h post-injection. RT-PCR screening revealed that Plx-PBAN cDNA was expressed in all examined body parts, with the highest expression level in the head of female adults. Analysis of RT-PCR products indicated the Plx-PBAN sequence was identical in all examined body parts of both sexes. Phylogenetic analysis revealed that the Plx-PBAN gene is distantly related to other PBANs, demonstrated by the relatively low similarity.
Keywords: Pheromone biosynthesis activating neuropeptide; Plutella xylostella; Pheromone production; FXPRL motif;
Discovery of an MIT-like atracotoxin family: Spider venom peptides that share sequence homology but not pharmacological properties with AVIT family proteins by Suping Wen; David T.R. Wilson; Sanjaya Kuruppu; Michael L.J. Korsinczky; Joseph Hedrick; Ling Pang; Tim Szeto; Wayne C. Hodgson; Paul F. Alewood; Graham M. Nicholson (2412-2426).
This project identified a novel family of six 66–68 residue peptides from the venom of two Australian funnel-web spiders, Hadronyche sp. 20 and H. infensa: Orchid Beach (Hexathelidae: Atracinae), that appear to undergo N- and/or C-terminal post-translational modifications and conform to an ancestral protein fold. These peptides all show significant amino acid sequence homology to atracotoxin-Hvf17 (ACTX–Hvf17), a non-toxic peptide isolated from the venom of H. versuta, and a variety of AVIT family proteins including mamba intestinal toxin 1 (MIT1) and its mammalian and piscine orthologs prokineticin 1 (PK1) and prokineticin 2 (PK2). These AVIT family proteins target prokineticin receptors involved in the sensitization of nociceptors and gastrointestinal smooth muscle activation. Given their sequence homology to MIT1, we have named these spider venom peptides the MIT-like atracotoxin (ACTX) family. Using isolated rat stomach fundus or guinea-pig ileum organ bath preparations we have shown that the prototypical ACTX–Hvf17, at concentrations up to 1 μM, did not stimulate smooth muscle contractility, nor did it inhibit contractions induced by human PK1 (hPK1). The peptide also lacked activity on other isolated smooth muscle preparations including rat aorta. Furthermore, a FLIPR Ca2+ flux assay using HEK293 cells expressing prokineticin receptors showed that ACTX–Hvf17 fails to activate or block hPK1 or hPK2 receptors. Therefore, while the MIT-like ACTX family appears to adopt the ancestral disulfide-directed β-hairpin protein fold of MIT1, a motif believed to be shared by other AVIT family peptides, variations in the amino acid sequence and surface charge result in a loss of activity on prokineticin receptors.
Keywords: ACTX–Hvf17; Mamba intestinal toxin 1; Bv8; Prokineticin; Funnel-web spider;
Genomic organization of four novel nondisulfide-bridged peptides from scorpion Mesobuthus martensii Karsch: Gaining insight into evolutionary mechanism by Feng Luo; Xian-Chun Zeng; Richard Hahin; Zhi-Jian Cao; Hui Liu; Wen-Xin Li (2427-2433).
At least 25 nondisulfide-bridged peptides (NDBPs) have been identified and characterized from scorpions. However, the genomic organization of the genes that encode these peptides have not been reported yet. BmKa1, BmKa2 and BmKb1 are three novel genes that code for NDBPs identified by our group from Mesobuthus martensii Karsch. Based on their cDNA sequences, the genomic DNA sequences encoding these peptides were obtained using the PCR method. Sequence analysis showed that three distinct genomic structural patterns are used to encode these three peptides. The BmKa1 gene is not interrupted by any introns. However, the BmKa2 gene is composed of two exons, interrupted by a 67 bp intron that is located in the DNA region encoding the mature peptide. Two genomic homologues of the BmKb1 cDNA sequence, named BmKb1′ and BmKb2, respectively, were obtained. The BmKb1′ gene contains one intron of 593 bp, inserted into the DNA region that encodes the signal peptide. Similarly, the BmKb2 gene also contains an intron that interrupts the exon that encodes the NDBP signal peptide. The amino acid sequences deduced for BmKb2 and BmKb1′ differ only at one position. The data suggest that the genomic organizational pattern of NDBPs displays more divergence than that exhibited by the genes that encode disulfide-bridged peptides from scorpions.
Keywords: Mesobuthus martensii Karsch; Nondisulfide-bridged peptide (NDBP); Genomic organization; BmKa1; BmKa2; BmKb1; BmKb2;
Circadian oscillations of RPCH gene expression in the eyestalk of the crayfish Cherax quadricarinatus by Francisco Martínez-Pérez; Samuel Zinker; Guadalupe Aguilar; Jesús Valdés; Hugo Aréchiga (2434-2444).
The RPCH and β-actin cDNAs from the crayfish Cherax quadricarinatus were amplified, cloned and sequenced. The primary structure sequences of these cDNAs were compared to other members of the AKH/RPCH family. Fluctuations in the amount of the C. quadricarinatus RPCH and β-actin mRNAs, as cDNAs, were quantified every 3 h by RT-PCR. Single cosinor analysis supports the notion of β-actin and RPCH mRNA circadian behavior in animals subjected to 12 h:12 h light/dark regimes. In constant darkness RPCH mRNA concentration changes to ultradian cycles.
Keywords: Crayfish; Crustacean; Cherax quadricarinatus; RPCH gene; β-Actin gene; Neurohormone; Neuropeptide; Circadian rhythm; Ultradian rhythm;
Novel frenatins from the skin of the Australasian giant white-lipped tree frog, Litoria infrafrenata: Cloning of precursor cDNAs and identification in defensive skin secretion by Mei Zhou; Tianbao Chen; Brian Walker; Chris Shaw (2445-2451).
The Australasian anuran amphibian genus Litoria, contains many phenotypically-diverse species as a result of radial evolution of an ancestral species into different biotopes much in the manner of the indigenous marsupial mammals. In common with members of the Central/South American genus Phyllomedusa, their specialized skin granular glands are factories for the production of a plethora of biologically-active peptides. Here we report a more detailed study of those present in the defensive skin secretion of the Australasian giant white-lipped tree frog, Litoria infrafrenata, and, for the first time, we have identified three novel frenatins by deduction of primary structures from cDNAs that were cloned from a library constructed from lyophilized skin secretion using a recently-developed technique. All open-reading frames consisted of a putative signal peptide and an acidic pro-region followed by a single copy of a frenatin peptide. Processed peptides corresponding in molecular mass to the deduced molecular masses of frenatins (named 1.1, 3, 3.1 and 4.1) were identified in the same secretion sample using HPLC and mass spectroscopy. The application of this technique thus permits parallel peptidomic and transcriptomic analyzes on the same lyophilized skin secretion sample circumventing sacrifice of specimens from endangered herpetofauna.
Keywords: Amphibian; Cloning; Mass spectrometry; Antimicrobial peptide;
Angiotensin II and III upregulate body fluid volume of the clam worm Perinereis sp. via angiotensin II receptors in different manners by Ryousuke Satou; Tsutomu Nakagawa; Hiroki Ido; Masayuki Tomomatsu; Fumiaki Suzuki; Yukio Nakamura (2452-2457).
Angiotensin III (Ang III) as well as angiotensin II (Ang II) suppressed body weight loss of the clam worm Perinereis sp. under a hyper-osmotic condition, and enhanced body weight gain under a hypo-osmotic condition. Under a drying condition where the water inflow from outside the body was eliminated, Ang II suppressed body weight loss, but Ang III did not. Under these conditions, angiotensins I, IV, and (1–7) had no effect, and saralasin blocked the effects of Ang II and Ang III. It is concluded that Ang II and Ang III upregulate body fluid volume of the clam worm via Ang II receptors in different ways.
Keywords: Angiotensin; Saralasin; Water regulation; Clam worm; Angiotensin II receptor;
Angiotensin II-induced venoconstriction involves both AT1 and AT2 receptors and is counterbalanced by nitric oxide by Liliam Fernandes; Rodrigo Azevedo Loiola; Rita C.A. Tostes; Dorothy Nigro; Zuleica Bruno Fortes; Maria Helena Catelli de Carvalho (2458-2463).
The venoconstrictor effect of Angiotensin II (Ang II) was investigated in the rat mesenteric venules and portal vein. Mesenteric venules were perfused at a constant rate and reactivity to Ang II (0.1 nmol) was evaluated as changes in the perfusion pressure. Rings of portal vein were mounted in organ baths and curves to Ang II (0.1–100 nmol/L) were generated. In venules, Ang II-contraction (10.6 ± 1.1 mmHg) was abolished by losartan (0.9 ± 0.3 mmHg*), reduced by PD 123,319 (5.8 ± 0.9 mmHg*), increased by l-NAME (16.5 ± 1.8 mmHg*) and not altered by indomethacin. In portal veins, curves to Ang II (−log EC50: 8.9 ± 0.1 mol/L) were shifted to the right by losartan (−log EC50: 7.5 ± 0.1 mol/L*) and by PD 123,319 (−log EC50: 8.0 ± 0.1 mol/L*). l-NAME increased the maximal response to Ang II (E max: 0.91 ± 0.1 g versus 1.62 ± 0.3 g*) and indomethacin had no effect. In conclusion, Ang II induces venoconstriction by activating AT1 and AT2 receptors. Data obtained with l-NAME provide evidence that the basal nitric oxide release from the endothelium of the venous system can modulate the Ang II-induced venoconstriction.
Keywords: Angiotensin; Veins; Venules; Nitric oxide; Receptors;
Expression of urotensin-II in human coronary atherosclerosis by Ghada S. Hassan; Stephen A. Douglas; Eliot H. Ohlstein; Adel Giaid (2464-2472).
The vasoactive peptide urotensin-II (U-II) is best known for its ability to regulate peripheral vascular and cardiac contractile function in vivo, and recent in vitro studies have suggested a role for the peptide in the control of vascular remodeling by inducing smooth muscle proliferation and fibroblast-mediated collagen deposition. Therefore, U-II may play a role in the etiology of atherosclerosis. In the present study we sought to determine the expression of U-II in coronary arteries from patients with coronary atherosclerosis and from normal control subjects, using immunohistochemistry and in situ hybridization. In normal coronary arteries, there was little expression of U-II in all types of cells. In contrast, in patients with coronary atherosclerosis, endothelial expression of U-II was significantly increased in all diseased segments (P < 0.05). Greater expression of U-II was noted in endothelial cells of lesions with subendothelial inflammation or fibrofatty lesion compared with that of endothelial cells underlined by dense fibrosis or minimal intimal thickening. Myointimal cells and foam cells also expressed U-II. In most diseased segments, medial smooth muscle cells exhibited moderate expression of U-II. These findings demonstrate upregulation of U-II in endothelial, myointimal and medial smooth muscle cells of atherosclerotic human coronary arteries, and suggest a possible role for U-II in the pathogenesis of coronary atherosclerosis.
Keywords: Immunohistochemistry; mRNA; Tissue; Coronary arteries;
Effects of urocortin II on neonatal rat cardiac myocytes and non-myocytes by Keiichi Ikeda; Katsuyoshi Tojo; Chikara Otsubo; Takashi Udagawa; Tatsuo Hosoya; Naoko Tajima; Kazuwa Nakao; Masahiro Kawamura (2473-2481).
Urocortin (Ucn) II and III, homologous peptides of Ucn that are specific ligands for corticotropin-releasing hormone (CRH) type 2 receptor (CRH-R2), have recently been identified. The present study was designed to elucidate the effects of Ucn II, which is predominantly expressed in rodent heart, on neonatal rat cardiac myocytes (MCs) and cardiac non-myocytes (NMCs). Ucn II increased the incorporation of [3H]-leucine into MCs, as well as the accumulation of cAMP and the secretion of atrial natriuretic peptide. However, no significant changes were demonstrated in NMCs or an MC/NMC co-culture system. The effects of Ucn II were attenuated by astressin2-B, a specific antagonist of CRH-R2, and/or H89, an inhibitor of protein kinase A (PKA). These results indicate that Ucn II may be another endogenous cardiovascular substance that acts via CRH-R2 and the cAMP-dependent PKA pathway.
Keywords: Urocortin; Urocortin II; Urocortin III; Astressin2-B; Corticotropin-releasing hormone receptor; Cardiac myocyte;
Proteolytic processing pattern of the endothelin-1 precursor in vivo by Joachim Struck; Nils G. Morgenthaler; Andreas Bergmann (2482-2486).
Endothelin-1 (ET-1) is a potent vasoconstrictor, which has been implicated in diseases involving dysfunctions of the cardiovascular system. For the biogenesis of ET-1, a larger precursor peptide (proET-1) is cleaved at two sites to give rise to bigET-1, which is subsequently cleaved to generate mature ET-1. In the present study, we investigated, which other peptides are derived from proET-1 in vivo. Six sandwich immunoassays covering various regions of proET-1 were developed and used to detect circulating proET-1 immunoreactivities in plasma of healthy subjects and septic patients. With this approach we could (a) demonstrate that, in addition to bigET-1/ET-1, three stable proET-1 fragments are generated, (b) exclude two previously discussed regions as sites for prohormone conversion and (c) show that the proteolytic processing pattern of proET-1 is unchanged under pathological conditions, which are associated with elevated levels of proET-1 fragments. The high stability and similarity in concentration of the proET-1 fragments suggest that these might be non-functional in the circulation. Stable proET-1 fragments maybe used in the future as reliable diagnostic targets to indirectly assess the release of ET-1, which might help to more selectively direct therapeutic measures.
Keywords: Sepsis; Shock; Prohormone; Biomarker; Cardiovascular dysfunction; Endothelium;
Endothelin-1 response to mental stress in early ischemic lesions of the extremities due to systemic sclerosis by Fiorella Fontana; Pasquale Bernardi; Giuseppina Lanfranchi; Eleonora Conti; Santi Spampinato; Rosanna Di Toro; Francesca Bonafè; Sergio Coccheri (2487-2490).
We studied circulating levels of endothelin-1, catecholamines and nitric oxide after a mental arithmetic test in 14 patients with early ischemic lesions of the extremities due to systemic sclerosis and slightly impaired peripheral vascular flow. The test induced an increase (P < 0.01) in blood pressure, heart rate, endothelin-1 and catecholamine levels, whereas it did not change the low basal levels of nitric oxide. In healthy subjects (n = 20) the test significantly (P < 0.01) decreased endothelin-1 without affecting nitric oxide. The low basal levels of nitric oxide and the high plasma concentration of endothelin-1 after psychological stress cannot be explained by an impaired release from the limited ischemic lesions alone. This suggests a diffuse microvascular derangement that aggravates the course of peripheral microvascular ischemic lesions.
Keywords: Limb ischemia; Systemic sclerosis; Mental arithmetic test; Endothelin-1; Nitric oxide; Norepinephrine;
Albumin peptide: A molecular marker for trauma/hemorrhagic-shock in rat mesenteric lymph by Vicki L. Kaiser; Ziad C. Sifri; Maheswari Senthil; George S. Dikdan; Qi Lu; Da-Zhong Xu; Edwin A. Deitch (2491-2499).
Vascular permeability and endothelial cell damage has been shown to occur in rats subjected to trauma with hemorrhagic-shock. Although the factors responsible for the endothelial cell injury are unknown, it has been hypothesized that toxic factors produced in response to hemorrhagic-shock originate in the gut and are absorbed into the mesenteric lymphatics. Consistent with this hypothesis, it has been shown that lymph collected from animals subjected to trauma with hemorrhagic-shock (T/HS) results in a marked decrease in endothelial cell viability both in vitro and in vivo. We therefore compared the lymph collected pre-T/HS to samples collected during, and up to 3 h post-T/HS in order to identify a factor present or increased in post-T/HS lymph. This analysis revealed that a single cationic peptide band was significantly increased in post-T/HS lymph, but not in lymph from control animals subjected to trauma without hemorrhagic-shock (T/SS). This peptide was subsequently identified as the N-terminal 24 amino acids of rat serum albumin (RSA) by mass spectrometry and amino acid sequencing. Although the measured increase in the albumin peptide correlates with detectable shock lymph-induced endothelial cell toxicity, the peptide was not toxic to endothelial cells. We therefore propose that the significant increase in the albumin peptide is a marker for post-T/HS lymph-induced endothelial cell toxicity.
Keywords: Lymphatics; Peptide; Albumin; N-terminus; Trauma; Hemorrhagic-shock;
Copeptin, a stable peptide derived from the vasopressin precursor, is elevated in serum of sepsis patients by Joachim Struck; Nils G. Morgenthaler; Andreas Bergmann (2500-2504).
Vasopressin is one of the key regulators of the body's water and solute balance. When this balance is pathologically disturbed, determination of serum vasopressin concentrations might be a helpful tool for guiding therapy. However, due to its instability and considerable association to platelets, reliable measurement of circulating vasopressin is difficult to achieve, if at all. In search of a more robust way for quantifying vasopressin release, we identified copeptin, a glycopeptide with unknown function, as an alternative diagnostic target. Since copeptin is derived from the same precursor peptide as vasopressin, released amounts of copeptin should mirror those of vasopressin. With a newly developed sensitive sandwich immunoassay, we detected strongly elevated concentrations of fully processed copeptin in serum of septic shock patients. The magnitude of elevation and the high stability of copeptin in serum and plasma indicate that copeptin measurement is not affected by the problems, which are associated with the direct measurement of vasopressin, and thus is apparently suitable to indirectly determine the release of vasopressin.
Keywords: Vasopressin; Copeptin; Sepsis; Shock; Prohormone; Biomarker; Cardiovascular dysfunction;
Effects of intraplantar injections of nociceptin and its N-terminal fragments on nociceptive and desensitized responses induced by capsaicin in mice by Tsukasa Sakurada; Takaaki Komatsu; Tomoko Moriyama; Mika Sasaki; Kengo Sanai; Tohru Orito; Chikai Sakurada; Shinobu Sakurada (2505-2512).
Injection of capsaicin into the hindpaw has been employed as a model of chemogenic nociception in mice. Intraplantar injection of nociceptin (30–240 pmol) produced a significant and dose-dependent antinociceptive activity in the capsaicin test. The nociceptin N-terminal fragments, (1–11) and (1–13), were also active with a potency higher than nociceptin and comparable to nociceptin, respectively. Intraplantar injection of the nociceptin (1–7) fragment had no effect on capsaicin-induced nociception. Antinociception induced by nociceptin or nociceptin (1–13) was reversed significantly by intraplantar co-injection of [Nphe1]nociceptin (1–13)NH2, an orphan opioid receptor-like 1 (ORL1) receptor antagonist, whereas local injection of the antagonist did not interfere with the action of nociceptin (1–11). Nociceptin (1–11) was approximately 2.0-fold more potent than naturally occurring peptide nociceptin, and 10-fold more active than intraplantar morphine. Nociceptive licking/biting response to intraplantar injection of capsaicin was desensitized by repeated injections of capsaicin at the interval of 15 min. Desensitization induced by capsaicin was attenuated significantly by co-injection of nociceptin at much lower doses than antinociceptive ED50 for nociceptin. Capsaicin desensitization was also decreased by co-injection of nociceptin (1–11) and (1–13) to a similar extent. The present results indicate that not only nociceptin but also the N-terminal fragment (1–13) possesses a local peripheral antinociceptive action, which may be mediated by peripheral ORL1 receptors. In addition, the difference of the effective doses suggests that the antinociceptive action and inhibition of capsaicin-induced desenitization by nociceptin, nociceptin (1–11) and (1–13), may involve distinct mechanisms at the level of the peripheral nerve terminal.
Keywords: Nociceptin; N-Terminal fragments of nociceptin; Capsaicin-induced nociceptive response; Antinociception; Intraplantar injection; Capsaicin desensitization;
Morphine-induced overexpression of prepro-nociceptin/orphanin FQ in cultured astrocytes by Naoko Takayama; Hiroshi Ueda (2513-2517).
The effects of morphine on the gene expression of prepro-nociceptin/orphanin FQ (ppN/OFQ) in various primary cultured brain cells from embryonic day 17, rats were studied by use of real-time RT-PCR method. The basal level of ppN/OFQ mRNA in terms of ratio to the β-actin in astrocytes was equivalent to that in neurons, but 10-times higher than that in microglia. The addition of 1 μM morphine significantly enhanced the ppN/OFQ mRNA levels in cultured astrocytes, but not neurons or microglia. The enhancement was observed as early as 1 h after the addition of morphine, reached maximum at 6 h. There was a concentration-dependency between 30 nM to 1 μM. The morphine-induced enhancement was abolished by naloxone, an antagonist of μ opioid peptide receptor (MOP), wortmannin, a phosphoinositide 3-kinase (PI3K) inhibitor, and PD98059, a MEK inhibitor, but not by 1,10-phenanthroline, a metalloprotease inhibitor and U73122, a phospholipase C inhibitor. These profiles contrast to the data with morphine-induced enhancement of brain-derived growth factor (BDNF) gene expression in microglia, where 1,10-phenanthroline abolished the expression. Furthermore, the ELISA analysis revealed that the immunoreactive ppN/OFQ or N/OFQ level was also increased by morphine. The present findings suggest that astrocytes could play roles in the neuronal plasticity during morphine chronic treatments by enhancing gene expression of anti-opioid peptide, N/OFQ.
Keywords: Nociceptin/orphanin FQ; Anti-opioid; Dependence; Transactivation;
Endogenous PACAP acts as a stress response peptide to protect cerebellar neurons from ethanol or oxidative insult by David Vaudry; Carol Hamelink; Ruslan Damadzic; Robert L. Eskay; Bruno Gonzalez; Lee E. Eiden (2518-2524).
The rodent cerebellum is richly supplied with PACAPergic innervation. Exogenous pituitary adenylate cyclase-activating polypeptide (PACAP) increases cerebellar granule cell survival and differentiation in culture, and enhances the number of neuroblasts in the molecular and internal granule cell layers (IGL) when injected postnatally into the cerebellum in vivo. Here, we have investigated the role of endogenous PACAP during cerebellar development by comparing the morphology of normal and PACAP-deficient mouse cerebellum, and the response of cerebellar granule cells from normal and PACAP-deficient mice subjected to neurotoxic insult in culture. There was no difference in cerebellar volume or granule cell number, in 11-day-old wild type versus PACAP-deficient mice. Cultured cerebellar neurons from PACAP-deficient and wild type mice also showed no apparent differences in survival and differentiation either under depolarizing conditions, or non-depolarizing conditions in the presence or absence of either dibutyryl cAMP or 100 nM PACAP. However, cultured cerebellar neurons from PACAP-deficient mice were significantly more sensitive than wild type neurons to ethanol- or hydrogen peroxide-induced toxicity. Differential ethanol toxicity was reversed by addition of 100 nM exogenous PACAP, suggesting that endogenous PACAP has neuroprotective activity in the context of cellular insult or stress. The neuroprotective action of PACAP was mimicked by dibutryl cAMP, indicating that it occurred via activation of adenylate cyclase. These results indicate that PACAP might act to protect the brain from paraphysiological insult, including exposure to toxins or hypoxia.
Keywords: Knock-out; Granule neurons; Development;
Non-associative learning and anxiety in rats treated with a single systemic administration of the gastrin-releasing peptide receptor antagonist RC-3095 by Márcio Rodrigo Martins; Adalisa Reinke; Samira S. Valvassori; Roberta A. Machado; João Quevedo; Gilberto Schwartsmann; Rafael Roesler (2525-2529).
The gastrin-releasing peptide receptor (GRPR) has been implicated in the modulation of emotionally-motivated memory. In the present study, we investigated the role of the GRPR on non-emotional, non-associative memory, and anxiety. Adult male Wistar rats were given a systemic injection of the GRPR antagonist [D-Tpi6, Leu13 psi(CH2NH)-Leu14] bombesin (6–14) (RC-3095) (0.2, 1.0 or 5.0 mg/kg) 30 min before exposure to an open field or an elevated plus maze. Habituation to the open field was tested in a retention trial carried out 24 h after the first exposure to the open field. Rats given RC-3095 at the doses of 1.0 or 5.0 mg/kg showed impaired habituation. Animals treated with 5.0 mg/kg of RC-3095 spent significantly more time in the closed arms of the elevated plus maze. No effects of RC-3095 on locomotion or exploratory behavior were observed. The results implicate the GRPR in the regulation of non-emotional, non-associative memory as well as in anxiety.
Recombinant prohormone convertase 1 and 2 cleave purified pro cholecystokinin (CCK) and a synthetic peptide containing CCK 8 Gly Arg Arg and the carboxyl-terminal flanking peptide by Michael B. Tagen; Margery C. Beinfeld (2530-2535).
Purified recombinant prohormone convertase 1 and 2 (PC1 and PC2) cleave a peptide containing cholecystokinin (CCK) 8 Gly Arg Arg and the carboxyl-terminal peptide liberating CCK 8 Gly Arg Arg. PC1 and PC2 also cleave purified pro CCK, liberating the amino terminal pro-peptide while no carboxyl-terminal cleavage was detected. Under the conditions of the in vitro cleavage assay, it appears that the carboxyl-terminal cleavage site of pro CCK is not accessible to the enzymes while this site is readily cleaved in a synthetic peptide. Additional cellular proteins that unfold the prohormone may be required to expose the carboxyl-terminal site for cleavage.
Keywords: CCK; PC1; PC2; Prohormone processing; Prohormone structure;
Search for substrates for prolyl oligopeptidase in porcine brain by Inger Brandt; Kris De Vriendt; Bart Devreese; Jozef Van Beeumen; Walter Van Dongen; Koen Augustyns; Ingrid De Meester; Simon Scharpé; Anne-Marie Lambeir (2536-2546).
The function of prolyl oligopeptidase (PO) has been associated with several disorders of the central nervous system. The purpose of this study was to identify endogenous substrates for recombinant porcine PO in porcine brain. The smaller polypeptides were extracted from total brain homogenates and fractionated by two-dimensional chromatography prior to incubation with PO. Shifts in the mass spectrum between the control and the incubated sample, marked potential substrates. Using MSMS peptide sequencing techniques, we identified several fragments of intracellular proteins as potential substrates, which opens new perspectives for finding the function of PO in the intracellular space.
Keywords: Prolyl oligopeptidase; Brain; Peptidomics; 2D chromatography; Mass spectrometry;
Proinsulin C-peptide activates vagus efferent output in rats by K. Kimura; A. Niijima; R. Yoshida; T. Kitamura; A. Kamikawa; D.T. Furuya; N. Kitamura; A. Konno; H. Nakamoto; N. Sakane; T. Yoshida; M. Saito (2547-2553).
The aim of this study was to examine the effect of proinsulin C-peptide on the autonomic nervous systems in rats. Intravenous administration of C-peptide gradually increased electrophysiological activity of the vagus nerves into the stomach and pancreas for at least 90 min. It also slightly increased gastric acid secretion that was suppressed by the treatment with atropine. Intraperitoneal injection of C-peptide did not affect the basal and stress-induced norepinephrine (NE) turnover rate, a biochemical index of sympathetic nerve activity. These results indicate that C-peptide increases parasympathetic nerve activity without affecting sympathetic nerve activity. This could explain, at least in part, the ameliorating effects of C-peptide on impaired cardiac autonomic nerve functions in patients with type 1 diabetes.
Keywords: Atropine; C-peptide; Gastric acid; Norepinephrine; Parasympathetic nerve; Sympathetic nerve; Vagus;
High fat diet induced hepatic insulin resistance is not related to changes in hypothalamic mRNA expression of NPY, AgRP, POMC and CART in mice by A.C. Heijboer; P.J. Voshol; E. Donga; C.G. van Eden; L.M. Havekes; J.A. Romijn; H. Pijl; E.P.M. Corssmit (2554-2558).
The hypothalamic circuitry, apart from its impact on food intake, modulates insulin sensitivity to adapt metabolic conditions in the face of environmental fluctuations in nutrient availability. The purpose of the present study was to investigate the effects of 2 weeks high fat feeding in wildtype mice on (1) insulin sensitivity and triglyceride accumulation in liver and muscle in relation to (2) mRNA expression levels of Neuropeptide Y (NPY), Agouti-related protein (AgRP), pro-opiomelanocortin (POMC), and cocaine- and amphetamine-regulated transcript (CART) in the hypothalamus. Two weeks of high fat feeding induced hepatic insulin resistance in the presence of increased hepatic triglyceride accumulation. In muscle, however, 2 weeks of high fat feeding did not result in changes in insulin sensitivity or in triglyceride content. mRNA expression levels of NPY, AgRP, POMC, and CART in the hypothalamus were not different between the groups. This study shows that 2 weeks of high fat feeding in mice does not affect mRNA expression levels of NPY, AgRP, POMC or CART, in the whole hypothalamus, despite induction of hepatic, but not peripheral, insulin resistance. Therefore, a major physiological role of these neuroendocrine factors in the induction of hepatic insulin resistance during a high fat diet seems less likely.
Keywords: Diabetes; Brain; Metabolism; Insulin resistance; Neuropeptides;
Central leptin differentially modulates ultradian secretory patterns of insulin, leptin and ghrelin independent of effects on food intake and body weight by Effiong E. Otukonyong; Michael G. Dube; Rita Torto; Pushpa S. Kalra; Satya P. Kalra (2559-2566).
We tested the hypothesis that leptin acts centrally to differentially modulate the ultradian communication of leptin, insulin and ghrelin with the hypothalamus. The ultradian fluctuation of these hormones in plasma after central leptin gene therapy was analyzed. Increased leptin transgene expression in the hypothalamus significantly decreased energy intake and body weight concomitant with severe hypoleptinemia and hypoinsulinemia resulting from drastically suppressed peak heights with unchanged frequency discharge of these hormones. Ghrelin secretion was, however, increased solely due to increased pulse amplitude. In pair-fed control rats leptin and ghrelin secretion was unchanged. In conclusion, independent of restraint on caloric intake and weight, leptin acting centrally modulates only the pulse amplitude of ultradian rhythmicity of the three afferent signals involved in the hypothalamic integration of energy balance. Since rhythmic discharge patterns dictate target response of hormones, these findings reveal a novel hypothalamic action of leptin in the pathophysiology of the obesity-dependent metabolic syndrome.
Keywords: Ultradian secretion; Insulin; Ghrelin; Leptin modulation; Gene therapy;
AAV-mediated leptin receptor installation improves energy balance and the reproductive status of obese female Koletsky rats by Erin Keen-Rhinehart; Satya P. Kalra; Pushpa S. Kalra (2567-2578).
Leptin is a hormone secreted primarily by white adipocytes that regulates energy homeostasis and reproduction via CNS receptors. Koletsky (f/f) rats with a leptin receptor (OB-Rb) gene mutation are obese, diabetic and infertile. We employed recombinant adeno-associated viral (rAAV) vectors to transfer the human OB-Rb gene into the brains of female Koletsky rats to identify sites of leptin action in the brain. rAAV-OB-Rb was microinjected into the medial preoptic area (MPOA), the paraventricular nucleus (PVN), the ventromedial hypothalamus, the arcuate nucleus (ARC), or the dorsal vagal complex in the brainstem. Food intake and body weight were monitored bi-weekly for 55 days. Vaginal cytology was examined daily to assess estrous cyclicity. After sacrifice, uncoupling protein-1 (UCP-1) mRNA in brown adipose tissue and serum concentrations of leptin, insulin, glucose, estradiol and progesterone were measured. Expression of OB-Rb was documented by RT-PCR and site specificity of microinjection was verified by immunohistochemical detection of green fluorescent protein following a control microinjection of rAAV-GFP. OB-Rb installation in the ARC reduced food intake, however, energy expenditure, assessed by UCP-1 mRNA expression, was increased by OB-Rb installation in all sites except the PVN. When injected into the MPOA and ARC, rAAV-OB-Rb stimulated the reproductive axis as evidenced by normalization of estrous cycle length and increased luteinizing hormone releasing hormone concentrations in the hypothalamus. These studies show that long-term installation of a functional leptin receptor in the CNS is achievable using rAAV vectors and further show that leptin acts on specific sites in the brain to produce differential effects on food intake, energy expenditure and reproduction.
Keywords: Recombinant adeno-associated virus; Hypothalamic-pituitary-gonadal axis; Hypothalamic appetite regulating network; Energy expenditure; Neuropeptide Y; Proopiomelanocortin;
Neuropeptide receptor transcripts are expressed in the rat clitoris and oscillate during the estrus cycle in the rat vagina by David Dangoor; Eliezer Giladi; Mati Fridkin; Illana Gozes (2579-2584).
Vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP) and angiotensin 2 are key neuropeptides that innervate the sexual organs. For further understanding of neuropeptide involvement in female sexual function, we investigated peptide receptor mRNA expression using reverse transcription-polymerase chain reaction (RT-PCR) in the rat vagina and clitoris, and alteration during the shift from the proestrus to the estrus phase. VIP, angiotensin 2 and CGRP receptor subtypes transcripts were found to be expressed in the vagina and the clitoris. Significantly increased levels of angiotensin 2 and CGRP receptor subtypes transcripts were observed in the vagina as compared to the clitoris. Significant increases in the expression of the VIP receptor type 2 (VPAC2) mRNA and parallel increases in a novel VIP responsive gene, activity-dependent neuroprotective protein (ADNP) mRNA were detected in the rat vagina during the estrus phase. The expression pattern of neuropeptide receptors in the female sexual organs suggest an intimate involvement of the corresponding neuropeptides in female sexual function.
Keywords: Sexual function; Vasoactive intestinal peptide (VIP); Angiotensin 2; Calcitonin gene-related peptide (CGRP); Activity-dependent neuroprotective protein (ADNP);
Immunohistochemical localization of orexin-B, orexin-1 receptor, ghrelin, GHS-R in the lacrimal gland of normal and diabetic rats by E. Adeghate; R.S. Hameed (2585-2589).
Orexin-B, ghrelin and their receptors play an important role in the regulation of feeding in mammals. The pattern of distribution of orexin-B, orexin-1-receptor (OX1R), ghrelin and growth hormone secretagogue receptor (GHS-R) in the lacrimal gland of normal and diabetic rats has not been reported. Diabetes was induced by a single intraperitoneal injection of streptozotocin (STZ) at 60 mg kg−1. Forty weeks after the induction of STZ-induced diabetes, normal, age-matched controls and diabetic rats were anesthetized with chloral hydrate (intraperitoneally) and their lacrimal glands removed and processed for immunofluorescence. Orexin-B was observed in the cells localized to the interacinar regions while OX1R was discerned in the nerves innervating the wall of small blood vessels. Ghrelin was also present in a group of cells located in the periacinar regions of the lacrimal glands of normal and diabetic rats. In contrast, GHS-R was observed in the apical region of the ductal cells of the lacrimal glands of both normal and diabetic rats. The pattern of distribution of these orexigenic peptides and their receptors did not significantly change after the onset of diabetes. In conclusion, orexin-B, ghrelin and their receptors are present in the lacrimal glands of both normal and diabetic rats and may play a role in the regulation of lacrimal gland function.
Keywords: Orexin; Orexin receptors; Ghrelin; Ghrelin receptors; Immunofluorescence; Lacrimal gland; Diabetes mellitus; Rat;
Age-related changes of hypocretin in basal forebrain of guinea pig by Jian-Hua Zhang; Sharon Sampogna; Francisco R. Morales; Michael H. Chase (2590-2596).
Hypocretin-1 (hcrt-1) and hypocretin-2 (hcrt-2) have been implicated in a wide variety of functions including sleep and wakefulness as well as related behaviors. Many of these functions of the hypocretins involve the activation of cholinergic neurons in the basal forebrain (BF). These neurons have been shown to exhibit age-related changes in a variety of species. In the present experiment, in adult and aged guinea pigs, we compared hypocretin immunoreactivity in regions of the BF that include the medial septal nucleus (MS), the vertical and horizontal limbs of the diagonal band of Broca (VDB and HDB) and the magocellular preoptic nucleus (MCPO). In adult guinea pigs (3–5 months of age), all of the preceding BF regions contained dense hypocretin fibers with varicosities. On the contrary, in old guinea pigs (27–28 months), although the MS exhibited a similar intensity of hypocretin immunoreactivity compared with the adult guinea pig, there was a significant decrease in the intensity of immunoreactivity of hypocretinergic fibers in the VDB, HDB and MCPO. These data indicate that the hypocretinergic innervation of specific nuclei of the BF is compromised during the aging process. We suggest that the reduction in hypocretinergic innervation of the BF nuclei may contribute to the age-related changes in the states of sleep and wakefulness as well as deficits in related systems that occur in old age.
Keywords: Hypocretin; Immunoreactivity; Basal forebrain; Guinea pig; Aging;
Attenuated feeding responses to circadian and palatability cues in mice lacking neuropeptide Y by Dana K. Sindelar; Richard D. Palmiter; Stephen C. Woods; Michael W. Schwartz (2597-2602).
Neuropeptide Y (NPY) is a potent orexigenic peptide that is implicated in the feeding response to a variety of stimuli. The current studies employed mice lacking NPY (Npy−/−) and their wild-type (Npy+/+) littermates to investigate the role of this peptide in the feeding response to circadian and palatability cues. To investigate the response to a circadian stimulus, we assessed food intake during the 4-h period following dark onset, a time of day characterized by maximal rates of food consumption. Compared to Npy+/+ controls, intake of Npy−/− mice was reduced by 33% during this period (0.6 ± 0.1 g versus 0.9 ± 0.1 g; p ≤ 0.05). In contrast, intake did not differ between genotypes when measured over a 24-h period (3.7 ± 0.2 g versus 3.5 ± 0.3 g; p = ns). Furthermore, reduced dark cycle 4 h food intake in Npy−/− mice was not evident after a 24-h fast (1.4 ± 0.1 g for both genotypes; p = ns), despite a pronounced delay in the initiation of feeding (636 ± 133 s versus 162 ± 29 s; p ≤ 0.05). To investigate the role of NPY in the feeding response to palatability cues, mice were presented with a highly palatable diet (HP) for 1 h each day (in addition to having ad libitum access to chow) for 18 days. Npy+/+ mice rapidly increased daily HP intake such that by the end of the first week, they derived a substantial fraction of daily energy from this source (41 ± 3%). By comparison, HP intake was markedly reduced in Npy−/− mice during the first week (24 ± 7% of daily energy intake, p ≤ 0.05 versus Npy+/+), although it eventually increased (by Day 9) to values comparable to those of Npy+/+ controls. These experiments suggest that NPY contributes to the mechanism whereby food intake increases in response to circadian and palatability cues and that mechanisms driving food intake in response to these stimuli differ from those activated by energy restriction.
Keywords: Neuropeptide Y; Highly palatable diet; Circadian;
Influence of cold stress on neuropeptide Y and sympathetic neurotransmission by Songping Han; Xiaoli Chen; Chun-Lian Yang; Lillian Vickery; Yumei Wu; Linda Naes; Heather Macarthur; Thomas C. Westfall (2603-2609).
Chronic cold stress of rats (4 °C; 1–3 weeks) induced a marked increase in gene expression (adrenal medulla; superior cervical ganglia), tissue content (mesenteric arterial bed) and nerve stimulation-induced overflow of NPY-immunoreactivity (NPYir) from the perfused mesenteric arterial bed. In contrast increased NPY neurotransmission was offset by an apparent decrease in the evoked overflow of norepinephrine (NE) due to a presumed deactivation of NE by nitric oxide (NO), despite increased sympathetic nerve activity. The net effect of these offsetting system was no change in basal or the evoked increase in perfusion pressure (sympathetic tone). It is concluded that differences in NPY and NE transmission act as an important compensatory mechanism preventing dramatic changes in arterial pressure when sympathetic nerve activity is high during cold stress.
Keywords: Neuropeptide Y; Norepinephrine; Sympathetic neurotransmission; Cold stress; Nitric oxide; Mesenteric arterial bed; Adrenal medulla; Superior cervical ganglion; Neuroeffector junction;
Effect of adrenomedullin administration on acetic acid-induced colitis in rats by Shinya Ashizuka; Naoto Ishikawa; Johji Kato; Junichi Yamaga; Haruhiko Inatsu; Tanenao Eto; Kazuo Kitamura (2610-2615).
Adrenomedullin (AM) administered intracolonically ameliorated the severity of acetic acid-induced colonic ulceration in rats. Ulcers were induced by subserosal injection of acetic acid into the colon. AM-treated group was administered 0.25–1.0 μg of AM in 0.5 ml of saline intracolonically once a day; the control group received only saline. AM administration dose-dependently and significantly reduced the size of the ulcerative lesions, the associated edema, and the infiltration of the affected area by inflammatory cells. AM also reduced tissue levels of interleukin-6, but not interferon-γ. AM reduces the severity of acetic acid-induced colitis in rats, probably by inhibiting the production and/or release of Th-2 cell-derived factors such as interleukin-6.
Keywords: Acetic acid; Adrenomedullin; Colitis; Inflammatory bowel disease; T helper 2 cells;
Isolation and characterization of a glycine-extended form of calcitonin receptor-stimulating peptide-1: Another biologically active form of calcitonin receptor-stimulating peptide-1 by Takeshi Katafuchi; Kazumasa Hamano; Katsuro Kikumoto; Naoto Minamino (2616-2623).
In this study, we isolated a peptide eliciting a potent stimulatory effect on cAMP production in LLC-PK1 cells from acid extracts of porcine brain. By structural analysis, this peptide was determined to be a C-terminal glycine-extended form of calcitonin receptor-stimulating peptide-1 (CRSP-1-Gly). Synthetic CRSP-1-Gly enhanced the cAMP production in COS-7 cells expressing calcitonin (CT) receptor as strongly as CRSP-1. Measurement of immunoreactive (IR) CRSP-1-Gly by radioimmunoassay using the specific antisera against CRSP-1-Gly showed that a relatively high level (>1 pmol/g wet weight) of IR-CRSP-1-Gly was detected in the midbrain, hypothalamus, anterior and posterior lobes of pituitary, and thyroid gland, and the ratio of IR-CRSP-1-Gly to total IR-CRSP-1 varies from 0.02 to 0.35 in each tissue. These results suggest that CRSP-1-Gly is actually present in the tissues as one of major endogenous molecular forms of CRSP-1, and can regulate the cells expressing the CT receptor both in the central nervous system and peripheral tissues in a manner similar to that of CRSP-1. IR-CRSP-2 and IR-CRSP-3 are also present in the brain and other tissues, but their tissue concentrations are 33% on average and less than 3% that of total IR-CRSP-1, respectively.
Keywords: Calcitonin receptor-stimulating peptide; Glycine-extended form of calcitonin receptor-stimulating peptide; Isolation; Calcitonin receptor; cAMP; Radioimmunoassay;
Partial structure of the phylloxin gene from the giant monkey frog, Phyllomedusa bicolor: Parallel cloning of precursor cDNA and genomic DNA from lyophilized skin secretion by Tianbao Chen; Ron Gagliardo; Brian Walker; Mei Zhou; Chris Shaw (2624-2628).
Phylloxin is a novel prototype antimicrobial peptide from the skin of Phyllomedusa bicolor. Here, we describe parallel identification and sequencing of phylloxin precursor transcript (mRNA) and partial gene structure (genomic DNA) from the same sample of lyophilized skin secretion using our recently-described cloning technique. The open-reading frame of the phylloxin precursor was identical in nucleotide sequence to that previously reported and alignment with the nucleotide sequence derived from genomic DNA indicated the presence of a 175 bp intron located in a near identical position to that found in the dermaseptins. The highly-conserved structural organization of skin secretion peptide genes in P. bicolor can thus be extended to include that encoding phylloxin (plx). These data further reinforce our assertion that application of the described methodology can provide robust genomic/transcriptomic/peptidomic data without the need for specimen sacrifice.
Keywords: Phyllomedusinae; Venom; Peptide; Mass spectroscopy; Molecular cloning;
Endogenous opiates and behavior: 2004 by Richard J. Bodnar; Gad E. Klein (2629-2711).
This paper is the 27th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over 30 years of research. It summarizes papers published during 2004 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.
Keywords: Enk ephalins; Endorphin; Dynorphin; Mu opioid receptor; Delta opioid receptor; Kappa opioid receptor;