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Sample records for intestinal peptide stimulates

  1. Dopaminergic modulation of adenylate cyclase stimulation by vasoactive intestinal peptide in anterior pituitary.

    PubMed Central

    Onali, P; Schwartz, J P; Costa, E

    1981-01-01

    The activation of adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] by vasoactive intestinal peptide (VIP) was used as a model to investigate the molecular mechanisms triggered by the occupancy of dopamine recognition sites in rat anterior pituitary. Dopamine failed to change the basal enzyme activity, but it inhibited the stimulation of adenylate cyclase elicited by VIP. Apomorphine, 2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene, and 2-bromo-alpha-ergocryptine mimicked the effect of dopamine, whereas (-)-sulpiride and and classical neuroleptics antagonized it. Dopamine failed to modulate the activation of pituitary adenylate cyclase by prostaglandin E1, which does not increase prolactin secretion. From these results we infer that stimulation of D-2 (dopamine) receptors may affect pituitary secretion by inhibiting the activation of anterior pituitary adenylate cyclase by VIP or other secretagogues. PMID:6171819

  2. Effects of epithelium removal on relaxation of airway smooth muscle induced by vasoactive intestinal peptide and electrical field stimulation.

    PubMed Central

    Farmer, S. G.; Togo, J.

    1990-01-01

    1. We have studied the effect of epithelium removal on relaxation of guinea-pig isolated tracheal smooth muscle induced by vasoactive intestinal peptide (VIP) or stimulation of non-adrenergic, non-cholinergic (NANC) inhibitory nerves. Also examined were the effects of inhibitors of neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE). 2. Epithelium removal produced a 3.6 +/- 0.4 fold leftward shift in the VIP concentration-response curve. The supersensitivity to VIP, following epithelium removal was abolished by phosphoramidon or thiorphan (NEP inhibitors), but unaffected by captopril (an ACE inhibitor). In intact trachea, the NEP inhibitors produced leftward shifts in the VIP curves similar to those produced by epithelium removal. 3. In contrast to responses to exogenous VIP, neurogenic NANC inhibitory responses to electrical field stimulation were affected neither by epithelial denudation nor by the peptidase inhibitors. 4. As in previous studies, epithelium removal increased tracheal sensitivity to isoprenaline. This was not altered by pretreatment with a cocktail of peptidase inhibitors. Thus, the effect of the NEP inhibitors on responses to VIP appears to be relatively specific. 5. These data indicate that exogenous VIP is a substrate for airway NEP, since inhibition of the enzyme potentiates the peptide. This is further evidence that the airway epithelium provides a source for the metabolism of mediators. 6. In guinea-pig trachea the NEP responsible for cleaving VIP may be located largely in the epithelial layer, since NEP inhibition was without effect on sensitivity to VIP in epithelium-denuded preparations. If VIP is a NANC inhibitory neurotransmitter in this tissue its degradation endogenously does not appear to involve epithelial NEP. PMID:2196967

  3. Vasoactive intestinal peptide synergistically stimulates DNA synthesis in mouse 3T3 cells: Role of cAMP, Ca sup 2+ , and protein kinase C

    SciTech Connect

    Zurier, B.B.; Kozma, M.; Sinnett-Smith, J.; Rozengurt, E. )

    1988-05-01

    Vasoactive intestinal peptide synergistically stimulated initiation of DNA synthesis in Swiss 3T3 cells. The peptide stimulated ({sup 3}H)thymidine incorporation in the presence of insulin and either forskolin or an inhibitor of cAMP phosphodiesterase in a concentration-dependent manner. Half-maximal effect was obtained at 1 nM. At mitogenic concentrations, VIP stimulated a marked accumulation (eightfold) of cAMP. In contrast to other growth-promoting neuropeptides, VIP did not induce an increase in cytosolic free Ca{sup 2+} or the activation of protein kinase C. The authors conclude that neuropeptides can modulate long-term cell proliferation through multiple signaling pathways.

  4. Vasoactive intestinal peptide enhanced aromatase activity in the neonatal rat ovary before development of primary follicles or responsiveness to follicle-stimulating hormone

    SciTech Connect

    George, F.W.; Ojeda, S.R.

    1987-08-01

    The authors have investigated the factors that regulate aromatase activity in fetal-neonatal rat ovaries. Ovarian aromatase activity (assessed by measuring the amount of /sup 3/H/sub 2/O formed from (1..beta..-/sup 3/H)testosterone) is low prior to birth and increases to values greater than 30 pmol/hr per mg of protein between days 8 and 12 after birth. The appearance of ovarian aromatase coincides with the development of primordial follicles. Fetal-neonatal ovaries maintained in serum-free organ culture do not develop aromatase activity at the expected time. Ovine follicle-stimulating hormone, ovine luteinizing hormone, or their combination failed to induce the enzyme activity in cultured fetal ovaries, whereas follicle-stimulating hormone is effective in preventing the decline in aromatase activity when postnatal day 8 ovaries are placed in culture. In contrast to follicle-stimulating hormone, dibutyryl-cAMP markedly enhances ovarian aromatase in cultured fetal ovaries. Likewise, enhancement of endogenouse cAMP formation with forskolin or cholera toxin caused an increase in enzyme activity within 24 hr. Vasoactive intestinal peptide, a peptide known to occur in ovarian nerves, caused a dose-dependent increase in aromatase activity in fetal ovaries prior to folliculogenesis. Of related peptides tested, only the peptide having N-terminal histidine and C-terminal isoleucine amide was capable of inducing aromatase activity in fetal ovaries. The fact that VIP can induce aromatase activity in fetal rat ovaries prior to follicle formation and prior to responsiveness to follicle-stimulating hormone suggests that this neuropeptide may play a critical role in ovarian differentiation.

  5. Overview of intestinal adaptation and its stimulation.

    PubMed

    Robinson, M K; Ziegler, T R; Wilmore, D W

    1999-08-01

    Total parenteral nutrition (TPN) can be life-saving for many patients with short-bowel syndrome (SBS). However, chronic TPN administration is associated with nutritional deficiencies, septic complications, high health care costs, and life-threatening organ failure. In an effort to rehabilitate SBS patients so they may achieve enteral autonomy, investigators have attempted to stimulate the adaptive response following extensive small-bowel resection. Intestinal adaptation may include: 1) morphological changes of the residual bowel which increase the absorptive surface area; 2) functional changes that increase the absorptive capacity of individual enterocytes and colonocytes; and 3) changes in colonic production and absorption of short-chain fatty acids which improve intestinal vitality and maximize efficiency of energy and fluid absorption. Several peptides, nutrients, cytokines, and other factors promote intestinal adaptation in animals. These "growth" factors may predominantly affect one aspect of the adaptive response while having little or no effect on other physiologic or morphologic parameters. In addition, combined administration of stimulatory agents may be necessary to enhance adaptation. Dietary constituents may have profound positive and negative effects on adaptation and must be considered in developing an overall plan for treatment of the SBS patients. Only a few clinical studies have been performed to evaluate therapeutic regimens for SBS beyond standard supportive care and TPN administration. The combined administration of growth hormone, glutamine and a modified diet to over 225 adults has been shown to eliminate or decrease TPN dependence in 80% of patients receiving this therapy. Further study is required to optimize the treatment of humans with intestinal failure and to determine which patients are most likely to benefit from medical therapy. The authors conclude that the intestinal length to body weight index may be one predictive factor useful

  6. [Intestinal stimulation in patients with colostomy].

    PubMed

    Quesada, Ramón Ruiz

    2011-12-01

    We presented/displayed our experience in the recovery of the evacuator function of the intestine in patients entered in our service with direction diagnoses of Ileo Paralitico or Adinámico (Functional), that by some cause has been taken part surgically and is carrying of a temporary or permanent colostomia. Our experience is based on more than 10 patients, but we have only gathered the data of ten clinical histories. This stimulation we have obtained it, introducing a sounding Foley type through estoma, trying not to produce to the patient the minimum annoyance to him. We have looked for justification, as much physiological as anatomical, that it entails this answer of recovery of the intestinal peristaltismo, using body solid and not liquid, with idea that thus we respected better the normal intestinal operation in these patients, that already has it altered, to the being carrying of a colostomia.

  7. Stapled Vasoactive Intestinal Peptide (VIP) Derivatives Improve VPAC2 Agonism and Glucose-Dependent Insulin Secretion.

    PubMed

    Giordanetto, Fabrizio; Revell, Jefferson D; Knerr, Laurent; Hostettler, Marie; Paunovic, Amalia; Priest, Claire; Janefeldt, Annika; Gill, Adrian

    2013-12-12

    Agonists of vasoactive intestinal peptide receptor 2 (VPAC2) stimulate glucose-dependent insulin secretion, making them attractive candidates for the treatment of hyperglycaemia and type-II diabetes. Vasoactive intestinal peptide (VIP) is an endogenous peptide hormone that potently agonizes VPAC2. However, VIP has a short serum half-life and poor pharmacokinetics in vivo and is susceptible to proteolytic degradation, making its development as a therapeutic agent challenging. Here, we investigated two peptide cyclization strategies, lactamisation and olefin-metathesis stapling, and their effects on VPAC2 agonism, peptide secondary structure, protease stability, and cell membrane permeability. VIP analogues showing significantly enhanced VPAC2 agonist potency, glucose-dependent insulin secretion activity, and increased helical content were discovered; however, neither cyclization strategy appeared to effect proteolytic stability or cell permeability of the resulting peptides.

  8. Cloning and expression of the human vasoactive intestinal peptide receptor.

    PubMed Central

    Sreedharan, S P; Robichon, A; Peterson, K E; Goetzl, E J

    1991-01-01

    Vasoactive intestinal peptide (VIP) is a neuroendocrine mediator found in the central and peripheral nervous system. Distinct subsets of neural, respiratory, gastrointestinal, and immune cells bear specific high-affinity receptors for VIP, which are associated with a guanine nucleotide-binding (G) protein capable of activating adenylate cyclase. A cDNA clone (GPRN1) encoding the human VIP receptor was identified in libraries prepared from the Nalm 6 line of leukemic pre-B lymphoblasts and the HT-29 line of colon carcinoma cells. The deduced 362-amino acid polypeptide sequence encoded by GPRN1 shares a seven-transmembrane-segment hydropathicity profile with other G protein-coupled receptors. Northern blot analyses identified a 2.7-kilobase transcript of the VIP receptor in Nalm 6 and HT-29 cells as well as in tissues from rat brain, colon, heart, lung, kidney, spleen, and small intestine. COS-6 cells transfected with GPRN1 bound 125I-labeled VIP specifically with a dissociation constant (Kd) of 2.5 nM. VIP--and less effectively secretin, peptide histidine isoleucine (PHI), and glucagon competitively displaced bound 125I-VIP from transfected COS-6 cells, with potencies in the order VIP greater than secretin = PHI much greater than glucagon. VIP stimulated adenylate cyclase activity in stably transfected Chinese hamster ovary K1 cells, inducing a 3-fold increase in the intracellular level of cAMP. When the antisense orientation of the VIP receptor clone was introduced into HT-29 cells, there was a 50% suppression of the specific binding of 125I-VIP and of the VIP-induced increase in cAMP level, relative to untransfected cells. The VIP receptor cloned exhibits less than or equal to 24% homology with other receptors in the same superfamily and thus represents a subset of G protein-coupled receptors for peptide ligands. Images PMID:1675791

  9. The immune-stimulating peptide WKYMVm has therapeutic effects against ulcerative colitis

    PubMed Central

    Kim, Sang Doo; Kwon, Soonil; Lee, Sung Kyun; Kook, Minsoo; Lee, Ha Young; Song, Ki-Duk; Lee, Hak-Kyo; Baek, Suk-Hwan; Park, Chan Bae; Bae, Yoe-Sik

    2013-01-01

    In this study, we examined the therapeutic effects of an immune-stimulating peptide, WKYMVm, in ulcerative colitis. The administration of WKYMVm to dextran sodium sulfate (DSS)-treated mice reversed decreases in body weight, bleeding score and stool score in addition to reversing DSS-induced mucosa destruction and shortened colon. The WKYMVm-induced therapeutic effect against ulcerative colitis was strongly inhibited by a formyl peptide receptor (FPR) 2 antagonist, WRWWWW, indicating the crucial role of FPR2 in this effect. Mechanistically, WKYMVm effectively decreases intestinal permeability by stimulating colon epithelial cell proliferation. WKYMVm also strongly decreases interleukin-23 and transforming growth factor-β production in the colon of DSS-treated mice. We suggest that the potent immune-modulating peptide WKYMVm and its receptor FPR2 may be useful in the development of efficient therapeutic agents against chronic intestinal inflammatory diseases. PMID:24030327

  10. Vasoactive intestinal peptide may participate in the vasodilation of the dog hepatic artery

    SciTech Connect

    Varga, G.; Kiss, J.Z.; Papp, M.; Vizi, E.S.

    1986-08-01

    The possible direct action of vasoactive intestinal peptide (VIP) on dog hepatic arterial wall or on the noradrenergic innervation of the artery was investigated in vitro. In addition, VIP-containing nerve fibers and terminals were located in the wall of the artery with immunochemical staining. Direct evidence showed that VIP did not affect the release of (TH)norepinephrine but reduced the response of the isolated hepatic artery to electrical field stimulation and exogenous norepinephrine. This suggest that the effect of VIP is postjunctional on the smooth muscle of the artery. VIP-containing nerve fibers and varicosities were observed in the adventitial and medial layer of the arterial wall. These findings strongly support the hypothesis that vasoactive intestinal peptide is a physiological mediator of vasodilation in the hepatic artery.

  11. Food Derived Bioactive Peptides and Intestinal Barrier Function

    PubMed Central

    Martínez-Augustin, Olga; Rivero-Gutiérrez, Belén; Mascaraque, Cristina; Sánchez de Medina, Fermín

    2014-01-01

    A wide range of food-derived bioactive peptides have been shown to exert health-promoting actions and are therefore considered functional foods or nutraceuticals. Some of these actions are related to the maintenance, reinforcement or repairment of the intestinal barrier function (IBF) whose role is to selectively allow the absorption of water, nutrients and ions while preventing the influx of microorganisms from the intestinal lumen. Alterations in the IBF have been related to many disorders, such as inflammatory bowel disease or metabolic syndrome. Components of IBF are the intestinal epithelium, the mucus layer, secretory immunoglobulin A and cells of the innate and adaptive immune systems. Here we review the effects of food derived bioactive peptides on these IBF components. In vitro and in vivo effects, both in healthy and disease states, have been reviewed. Although limited, the available information indicates a potential for food-derived peptides to modify IBF and to contribute to disease treatment, but further research is needed to better isolate responsible peptides, and to help define their mode of action. PMID:25501338

  12. Food derived bioactive peptides and intestinal barrier function.

    PubMed

    Martínez-Augustin, Olga; Rivero-Gutiérrez, Belén; Mascaraque, Cristina; Sánchez de Medina, Fermín

    2014-12-09

    A wide range of food-derived bioactive peptides have been shown to exert health-promoting actions and are therefore considered functional foods or nutraceuticals. Some of these actions are related to the maintenance, reinforcement or repairment of the intestinal barrier function (IBF) whose role is to selectively allow the absorption of water, nutrients and ions while preventing the influx of microorganisms from the intestinal lumen. Alterations in the IBF have been related to many disorders, such as inflammatory bowel disease or metabolic syndrome. Components of IBF are the intestinal epithelium, the mucus layer, secretory immunoglobulin A and cells of the innate and adaptive immune systems. Here we review the effects of food derived bioactive peptides on these IBF components. In vitro and in vivo effects, both in healthy and disease states, have been reviewed. Although limited, the available information indicates a potential for food-derived peptides to modify IBF and to contribute to disease treatment, but further research is needed to better isolate responsible peptides, and to help define their mode of action.

  13. cis-Peptide Bonds: A Key for Intestinal Permeability of Peptides? .

    PubMed

    Marelli, Udaya Kiran; Ovadia, Oded; Frank, Andreas Oliver; Chatterjee, Jayanta; Gilon, Chaim; Hoffman, Amnon; Kessler, Horst

    2015-10-19

    Recent structural studies on libraries of cyclic hexapeptides led to the identification of common backbone conformations that may be instrumental to the oral availability of peptides. Furthermore, the observation of differential Caco-2 permeabilities of enantiomeric pairs of some of these peptides strongly supports the concept of conformational specificity driven uptake and also suggests a pivotal role of carrier-mediated pathways for peptide transport, especially for scaffolds of polar nature. This work presents investigations on the Caco-2 and PAMPA permeability profiles of 13 selected N-methylated cyclic pentaalanine peptides derived from the basic cyclo(-D-Ala-Ala4 -) template. These molecules generally showed moderate to low transport in intestinal epithelia with a few of them exhibiting a Caco-2 permeability equal to or slightly higher than that of mannitol, a marker for paracellular permeability. We identified that the majority of the permeable cyclic penta- and hexapeptides possess an N-methylated cis-peptide bond, a structural feature that is also present in the orally available peptides cyclosporine A and the tri-N-methylated analogue of the Veber-Hirschmann peptide. Based on these observations it appears that the presence of N-methylated cis-peptide bonds at certain locations may promote the intestinal permeability of peptides through a suitable conformational preorganization.

  14. Models to predict intestinal absorption of therapeutic peptides and proteins.

    PubMed

    Antunes, Filipa; Andrade, Fernanda; Ferreira, Domingos; Nielsen, Hanne Morck; Sarmento, Bruno

    2013-01-01

    Prediction of human intestinal absorption is a major goal in the design, optimization, and selection of drugs intended for oral delivery, in particular proteins, which possess intrinsic poor transport across intestinal epithelium. There are various techniques currently employed to evaluate the extension of protein absorption in the different phases of drug discovery and development. Screening protocols to evaluate protein absorption include a range of preclinical methodologies like in silico, in vitro, in situ, ex vivo and in vivo. It is the careful and critical use of these techniques that can help to identify drug candidates, which most probably will be well absorbed from the human intestinal tract. It is well recognized that the human intestinal permeability cannot be accurately predicted based on a single preclinical method. However, the present social and scientific concerns about the animal well care as well as the pharmaceutical industries need for rapid, cheap and reliable models predicting bioavailability give reasons for using methods providing an appropriate correlation between results of in vivo and in vitro drug absorption. The aim of this review is to describe and compare in silico, in vitro, in situ, ex vivo and in vivo methods used to predict human intestinal absorption, giving a special attention to the intestinal absorption of therapeutic peptides and proteins.

  15. Neonate Intestinal Immune Response to CpG Oligodeoxynucleotide Stimulation

    PubMed Central

    Lacroix-Lamandé, Sonia; Rochereau, Nicolas; Mancassola, Roselyne; Barrier, Mathieu; Clauzon, Amandine; Laurent, Fabrice

    2009-01-01

    Background The development of mucosal vaccines is crucial to efficiently control infectious agents for which mucosae are the primary site of entry. Major drawbacks of these protective strategies are the lack of effective mucosal adjuvant. Synthetic oligodeoxynucleotides that contain several unmethylated cytosine-guanine dinucleotide (CpG-ODN) motifs are now recognized as promising adjuvants displaying mucosal adjuvant activity through direct activation of TLR9-expressing cells. However, little is known about the efficacy of these molecules in stimulating the intestinal immune system in neonates. Methodology/Principal Findings First, newborn mice received CpG-ODN orally, and the intestinal cytokine and chemokine response was measured. We observed that oral administration of CpG-ODN induces CXC and CC chemokine responses and a cellular infiltration in the intestine of neonates as detected by immunohistochemistry. We next compared the efficiency of the oral route to intraperitoneal administration in stimulating the intestinal immune responses of both adults and neonates. Neonates were more responsive to TLR9-stimulation than adults whatever the CpG-ODN administration route. Their intestinal epithelial cells (IECs) indirectly responded to TLR9 stimulation and contributed to the CXC chemokine response, whereas other TLR9-bearing cells of the lamina-propria produced CC chemokines and Th1-type cytokines. Moreover, we showed that the intestine of adult exhibited a significantly higher level of IL10 at homeostasis than neonates, which might be responsible for the unresponsiveness to TLR9-stimulation, as confirmed by our findings in IL10-deficient mice. Conclusions/Significance This is the first report that deciphers the role played by CpG-ODN in the intestine of neonates. This work clearly demonstrates that an intraperitoneal administration of CpG-ODN is more efficient in neonates than in adults to stimulate an intestinal chemokine response due to their lower IL-10

  16. Atrial natriuretic peptide stimulates salt secretion by shark rectal gland by releasing VIP

    SciTech Connect

    Silva, P.; Stoff, J.S.; Solomon, R.J.; Lear, S.; Kniaz, D.; Greger, R.; Epstein, F.H.

    1987-01-01

    Salt secretion by the isolated perfused rectal gland of the spiny dogfish shark, Squalus acanthias, is stimulated by synthetic rat atrial natriuretic peptide (ANP II) as well as extracts of shark heart, but not by 8-bromo-cyclic guanosine 5'-monophosphate. Cardiac peptides have no effect on isolated rectal gland cells or perfused tubules, suggesting that stimulation requires an intact gland. The stimulation of secretion by ANP II is eliminated by maneuvers that block neurotransmitter release. Cardiac peptides stimulate the release of vasoactive intestinal peptide (VIP), known to be present in rectal glands nerves, into the venous effluent of perfused glands in parallel with their stimulation of salt secretion, but the release of VIP induced by ANP II is prevented by perfusion with procaine. VIP was measured by radioimmunoassay. Cardiac peptides thus appear to regulate rectal gland secretion by releasing VIP from neural stores within the gland. It is possible that other physiological effects of these hormones might be explained by an action to enhanced local release of neurotransmitters.

  17. Immunocytochemical detection of vasoactive intestinal peptide-like and peptide histidine isoleucine-like peptides in the nervous system and the excretory system of adult Nippostrongylus brasiliensis.

    PubMed

    Foster, N

    1998-05-01

    Vasoactive intestinal peptide-like and peptide histidine isoleucine-like immunoreactivities were detected in the excretory duct of adult male and female Nippostrongylus brasiliensis, thus indicating the source of these two physiologically active peptides previously isolated from the excretory/secretory products of adult N. brasiliensis. In the nervous system immunoreactivity to both these peptides was confined to females and was found in the neurons of the ovijector associated ganglion. This is consistent with co-synthesis of vasoactive intestinal peptide-like and peptide histidine isoleucine-like peptides which has also been shown to occur in all mammalian vasoactive intestinal peptid-ergic neurons studied to date. However, in addition to this, and in common to some previous studies on helminth vasoactive intestinal peptide and peptide histidine isoleucine immunoreactivities, co-synthesis of the peptides was not indicated in a pair of branched neurons which projected posteriorly and peripherally from the ganglion associated with the ovijector of females and which terminated in two pairs of ganglia also exhibiting vasoactive intestinal peptide-like immunoreactivity only. The position of these ganglia indicated that they innervate muscles close to the body wall and may be responsible for the muscular contractions required for expulsion of eggs from female Nippostrongylus brasiliensis. This is also the first study to successfully detect these peptides in the excretory system of gastrointestinal nematodes.

  18. Vasoactive intestinal peptide and electrical activity influence neuronal survival

    SciTech Connect

    Brenneman, D.E.; Eiden, L.E.

    1986-02-01

    Blockage of electrical activity in dissociated spinal cord cultures results in a significant loss of neurons during a critical period in development. Decreases in neuronal cell numbers and SVI-labeled tetanus toxin fixation produced by electrical blockage with tetrodotoxin (TTX) were prevented by addition of vasoactive intestinal peptide (VIP) to the nutrient medium. The most effective concentration of VIP was 0.1 nM. At higher concentrations, the survival-enhancing effect of VIP on TTX-treated cultures was attenuated. Addition of the peptide alone had no significant effect on neuronal cell counts or tetanus toxin fixation. With the same experimental conditions, two closely related peptides, PHI-27 (peptide, histidyl-isoleucine amide) and secretin, were found not to increase the number of neurons in TTX-treated cultures. Interference with VIP action by VIP antiserum resulted in neuronal losses that were not significantly different from those observed after TTX treatment. These data indicate that under conditions of electrical blockade a neurotrophic action of VIP on neuronal survival can be demonstrated.

  19. Antisecretory effect of prescribed appetite stimulator drug cyproheptadine in rat intestine.

    PubMed

    Meddah, Bouchra; Limas-Nzouzi, Nicolas; Mamadou, Godefroy; Miantezila, Joe; Soudy, Imar Djibrine; Eto, Bruno

    2014-06-01

    Cyproheptadine (Cph) is an antiserotoninergic and antihistaminergic agent with alpha-blocking activity and central sedative effect. Cph has been found to be effective in stimulating appetite, but to our knowledge, its direct effects on the intestine have not been documented. We aimed to assess the antisecretory effects of Cph in rat proximal colon using Ussing chambers' technique. In basal and serotonin (5-HT)-stimulated conditions, Cph induced a dose-dependent reduction in short-circuit current (Isc). This effect was different in fed vs. fasted rats (EC50 = 1.9 × 10(-5 ) m and 4.9 × 10(-5 ) m, respectively). As expected, Cph induced a marked dose-dependent rightward shift of the concentration-response curve to 5-HT (pA2 = 5.4). The effect of Cph was found to be close to that of antisecretory agents in the following sequence: peptide YY > somatostatin > clonidine > Cph > C7-sorbin. To our knowledge, this is the first demonstration that Cph has a direct effect on the inhibition of electrogenic ionic secretion in intestinal epithelium in vitro. Our results indicate that Cph can modulate the intestinal transport of electrolytes and provide a new insight into the peripheral effects of this drug, which is frequently prescribed as appetite stimulator in developing countries.

  20. Acetylcholine-producing T cells in the intestine regulate antimicrobial peptide expression and microbial diversity.

    PubMed

    Dhawan, Shobhit; De Palma, Giada; Willemze, Rose A; Hilbers, Francisca W; Verseijden, Caroline; Luyer, Misha D; Nuding, Sabine; Wehkamp, Jan; Souwer, Yuri; de Jong, Esther C; Seppen, J; van den Wijngaard, René M; Wehner, Sven; Verdu, Elena; Bercik, Premek; de Jonge, Wouter J

    2016-11-01

    The cholinergic anti-inflammatory pathway reduces systemic tumor necrosis factor (TNF) via acetylcholine-producing memory T cells in the spleen. These choline acetyltransferase (ChAT)-expressing T cells are also found in the intestine, where their function is unclear. We aimed to characterize these cells in mouse and human intestine and delineate their function. We made use of the ChAT-enhanced green fluorescent protein (eGFP) reporter mice. CD4(Cre) mice were crossed to ChAT(fl/fl) mice to achieve specific deletion of ChAT in CD4(+) T cells. We observed that the majority of ChAT-expressing T cells in the human and mouse intestine have characteristics of Th17 cells and coexpress IL17A, IL22, and RORC The generation of ChAT-expressing T cells was skewed by dendritic cells after activation of their adrenergic receptor β2 To evaluate ChAT T cell function, we generated CD4-specific ChAT-deficient mice. CD4ChAT(-/-) mice showed a reduced level of epithelial antimicrobial peptides lysozyme, defensin A, and ang4, which was associated with an enhanced bacterial diversity and richness in the small intestinal lumen in CD4ChAT(-/-) mice. We conclude that ChAT-expressing T cells in the gut are stimulated by adrenergic receptor activation on dendritic cells. ChAT-expressing T cells may function to mediate the host AMP secretion, microbial growth and expansion.

  1. Microbiota/Host Crosstalk Biomarkers: Regulatory Response of Human Intestinal Dendritic Cells Exposed to Lactobacillus Extracellular Encrypted Peptide

    PubMed Central

    Al-Hassi, Hafid O.; Mann, Elizabeth R.; Urdaci, María C.; Knight, Stella C.; Margolles, Abelardo

    2012-01-01

    The human gastrointestinal tract is exposed to a huge variety of microorganisms, either commensal or pathogenic; at this site, a balance between immunity and immune tolerance is required. Intestinal dendritic cells (DCs) control the mechanisms of immune response/tolerance in the gut. In this paper we have identified a peptide (STp) secreted by Lactobacillus plantarum, characterized by the abundance of serine and threonine residues within its sequence. STp is encoded in one of the main extracellular proteins produced by such species, which includes some probiotic strains, and lacks cleavage sites for the major intestinal proteases. When studied in vitro, STp expanded the ongoing production of regulatory IL-10 in human intestinal DCs from healthy controls. STp-primed DC induced an immunoregulatory cytokine profile and skin-homing profile on stimulated T-cells. Our data suggest that some of the molecular dialogue between intestinal bacteria and DCs may be mediated by immunomodulatory peptides, encoded in larger extracellular proteins, secreted by commensal bacteria. These peptides may be used for the development of nutraceutical products for patients with IBD. In addition, this kind of peptides seem to be absent in the gut of inflammatory bowel disease patients, suggesting a potential role as biomarker of gut homeostasis. PMID:22606249

  2. Microbiota/host crosstalk biomarkers: regulatory response of human intestinal dendritic cells exposed to Lactobacillus extracellular encrypted peptide.

    PubMed

    Bernardo, David; Sánchez, Borja; Al-Hassi, Hafid O; Mann, Elizabeth R; Urdaci, María C; Knight, Stella C; Margolles, Abelardo

    2012-01-01

    The human gastrointestinal tract is exposed to a huge variety of microorganisms, either commensal or pathogenic; at this site, a balance between immunity and immune tolerance is required. Intestinal dendritic cells (DCs) control the mechanisms of immune response/tolerance in the gut. In this paper we have identified a peptide (STp) secreted by Lactobacillus plantarum, characterized by the abundance of serine and threonine residues within its sequence. STp is encoded in one of the main extracellular proteins produced by such species, which includes some probiotic strains, and lacks cleavage sites for the major intestinal proteases. When studied in vitro, STp expanded the ongoing production of regulatory IL-10 in human intestinal DCs from healthy controls. STp-primed DC induced an immunoregulatory cytokine profile and skin-homing profile on stimulated T-cells. Our data suggest that some of the molecular dialogue between intestinal bacteria and DCs may be mediated by immunomodulatory peptides, encoded in larger extracellular proteins, secreted by commensal bacteria. These peptides may be used for the development of nutraceutical products for patients with IBD. In addition, this kind of peptides seem to be absent in the gut of inflammatory bowel disease patients, suggesting a potential role as biomarker of gut homeostasis.

  3. Glucagon-like peptide-2 induces rapid digestive adaptation following intestinal resection in preterm neonates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Short bowel syndrome (SBS) is a frequent complication after intestinal resection in infants suffering from intestinal disease. We tested whether treatment with the intestinotrophic hormone glucagon-like peptide-2 (GLP-2) increases intestinal volume and function in the period immediately following in...

  4. The role of vasoactive intestinal peptide in scavenging singlet oxygen

    SciTech Connect

    Misra, B.R.; Misra, H.P. )

    1990-02-26

    The neuropeptide vasoactive intestinal peptide (VIP), a highly basic 28 amino acid peptide, has a widespread distribution in the body. The functional specificity of this peptide not only includes its potent vasodilatory activity, but also its role in protecting lungs against acute injury, in preventing T-lymphocyte proliferation and in modulating immune function. The purpose of this study was to examine the possible antioxidant properties of VIP. The authors found that VIP up to 50 {mu}g/ml had no inhibitory effect on its reduction of cytochrome C by xanthine and xanthine oxidase, indicating that the peptide does not have significant O{sub 2} scavenging ability. However, VIP was found to inhibit, in a dose-dependent manner, the {sup 1}O{sub 2} dependent 2, 2, 6, 6 tetramethyl piperidine oxide (TEMPO) formation. {sup 1}O{sub 2} was produced by rose benzal photosensitizing system and was detected as TEMP-{sup 1}O{sub 2} adduct (TEMPO) by electron paramagnetic resonance (EPR) spectroscopic technique. The formation of TEMPO signal was strongly inhibited by {beta}-carotene, histidine as well as azide, but not by superoxide dismutase (48 {mu}g/ml), catalase (20 {mu}g/ml) and mannitol (6mM), indicating that TEMPO signal was a TEMP-{sup 1}O{sub 2} adduct. These results indicate that VIP has potent antioxidant activity and may serve as a singlet O{sub 2} scavenger, thus it may modulate the oxidative tissue injury caused by this reactive oxygen species.

  5. Postinjury Vagal Nerve Stimulation Protects Against Intestinal Epithelial Barrier Breakdown

    PubMed Central

    Krzyzaniak, Michael; Peterson, Carrie; Loomis, William; Hageny, Ann-Marie; Wolf, Paul; Reys, Luiz; Putnam, James; Eliceiri, Brian; Baird, Andrew; Bansal, Vishal; Coimbra, Raul

    2014-01-01

    Background Vagal nerve stimulation (VNS) can have a marked anti-inflammatory effect. We have previously shown that preinjury VNS prevented intestinal barrier breakdown and preserved epithelial tight junction protein expression. However, a pretreatment model has little clinical relevance for the care of the trauma patient. Therefore, we postulated that VNS conducted postinjury would also have a similar protective effect on maintaining gut epithelial barrier integrity. Methods Male balb/c mice were subjected to a 30% total body surface area, full-thickness steam burn followed by right cervical VNS at 15, 30, 60, 90, 120, and 150 minutes postinjury. Intestinal barrier dysfunction was quantified by permeability to 4 kDa fluorescein isothiocyanate-Dextran, histologic evaluation, gut tumor necrosis factor-alpha (TNF-α) enzyme-linked immunosorbent assay, and expression of tight junction proteins (myosin light chain kinase, occludin, and ZO-1) using immunoblot and immunoflourescence. Results Histologic examination documented intestinal villi appearance similar to sham if cervical VNS was performed within 90 minutes of burn insult. VNS done after injury decreased intestinal permeability to fluorescein isothiocyanate-Dextran when VNS was ≤90 minutes after injury. Burn injury caused a marked increase in intestinal TNF-α levels. VNS-treated animals had TNF-α levels similar to sham when VNS was performed within 90 minutes of injury. Tight junction protein expression was maintained at near sham values if VNS was performed within 90 minutes of burn, whereas expression was significantly altered in burn. Conclusion Postinjury VNS prevents gut epithelial breakdown when performed within 90 minutes of thermal injury. This could represent a therapeutic window and clinically relevant strategy to prevent systemic inflammatory response distant organ injury after trauma. PMID:21610431

  6. The Responses of Rat Intestinal Brush Border and Cytosol Peptide Hydrolase Activities to Variation in Dietary Protein Content DIETARY REGULATION OF INTESTINAL PEPTIDE HYDROLASES

    PubMed Central

    Nicholson, J. Alex; McCarthy, Denis M.; Kim, Young S.

    1974-01-01

    The effects of variation in dietary protein content on small intestinal brush border and cytosol peptide hydrolase activities have been investigated. One group of rats was fed a high protein diet (55% casein) and another group was fed a low protein diet (10% casein). After 1 wk, brush border peptide hydrolase activity (L-leucyl-β-naphthylamide as substrate) and cytosol peptide hydrolase activity (L-prolyl-L-leucine as substrate) were determined in mucosae taken from the proximal, middle, and distal small intestine. As judged by several parameters, brush border peptide hydrolase activity was significantly greater in rats fed the high protein diet when data for corresponding segments were compared. In contrast, no significant difference was seen in cytosol peptide hydrolase activity. In a second study, brush border and cytosol peptide hydrolase activities were determined in the proximal intestine by utilizing an additional three peptide substrates: L-leucyl-L-alanine, L-phenylalanylglycine, and glycyl-L-phenylalanine. Sucrase, maltase, and alkaline phosphatase activities were also determined. As before, brush border peptide hydrolase activities were significantly greater in rats fed the high protein diet. However, activities of the nonproteolytic brush border enzymes did not vary significantly with diet. In contrast to the results obtained with L-prolyl-L-leucine as substrate for the cytosol enzymes, cytosol activity against the three additional peptide substrates was greater in rats fed the high protein diet. It is suggested that the brush border peptide hydrolase response to variation in dietary protein content represents a functional adaptation analogous to the regulation of intestinal disaccharidases by dietary carbohydrates. The implication of the differential responses of the cytosol peptide hydrolases is uncertain, since little is known of the functional role of these nonorgan-specific enzymes. PMID:4430719

  7. A novel method for the culture and polarized stimulation of human intestinal mucosa explants.

    PubMed

    Tsilingiri, Katerina; Sonzogni, Angelica; Caprioli, Flavio; Rescigno, Maria

    2013-05-01

    Few models currently exist to realistically simulate the complex human intestine's micro-environment, where a variety of interactions take place. Proper homeostasis directly depends on these interactions, as they shape an entire immunological response inducing tolerance against food antigens while at the same time mounting effective immune responses against pathogenic microbes accidentally ingested with food. Intestinal homeostasis is preserved also through various complex interactions between the microbiota (including food-associated beneficial bacterial strains) and the host, that regulate the attachment/degradation of mucus, the production of antimicrobial peptides by the epithelial barrier, and the "education" of epithelial cells' that controls the tolerogenic or immunogenic phenotype of unique, gut-resident lymphoid cells' populations. These interactions have been so far very difficult to reproduce with in vitro assays using either cultured cell lines or peripheral blood mononuclear cells. In addition, mouse models differ substantially in components of the intestinal mucosa (mucus layer organization, commensal bacteria community) with respect to the human gut. Thus, studies of a variety of treatments to be brought in the clinics for important stress-related or pathological conditions such as irritable bowel syndrome, inflammatory bowel disease or colorectal cancer have been difficult to carry out. To address these issues, we developed a novel system that enables us to stimulate explants of human intestinal mucosa that retain their in situ conditioning by the host microbiota and immune response, in a polarized fashion. Polarized apical stimulation is of great importance for the outcome of the elicited immune response. It has been repeatedly shown that the same stimuli can produce completely different responses when they bypass the apical face of the intestinal epithelium, stimulating epithelial cells basolaterally or coming into direct contact with lamina

  8. Actions of vasoactive intestinal peptide and secretin on chief cells prepared from guinea pig stomach

    SciTech Connect

    Sutliff, V.E.; Raufman, J.P.; Jensen, R.T.; Gardner, J.D.

    1986-07-01

    Vasoactive intestinal peptide and secretin increased cellular cAMP and pepsinogen secretion in dispersed chief cells from guinea pig gastric mucosa. With each peptide there was a close correlation between the dose-response curve for changes in cellular cAMP and that for changes in pepsinogen secretion. Vasoactive intestinal peptide- (10-28) and secretin- (5-27) had no agonist activity and antagonized the actions of vasoactive intestinal peptide and secretin on cellular cAMP and pepsinogen secretion. Studies of binding of SVI-vasoactive intestinal peptide and of SV-secretin indicated that gastric chief cells possess four classes of binding sites for vasoactive intestinal peptide and secretin and that occupation of two of these classes of binding sites correlates with the abilities of vasoactive intestinal peptide and secretin to increase cellular cAMP and pepsinogen secretion. What function, in any, is mediated by occupation by the other two classes of binding sites remains to be determined.

  9. The effects of vasoactive intestinal peptide on adrenal steroid hormone secretion

    SciTech Connect

    Cunningham, L.A.

    1988-01-01

    Vasoactive intestinal peptide (VIP)-immunoreactive nerve fibers have been demonstrated in the rat adrenal cortex in close association with zona glomerulosa cells. We have studied the effects of VIP on steroid hormone secretion from the outer zones of the normal rat adrenal cortex. Intact capsule-glomerulosa preparations, consisting of the capsule, zona glomerulosa, and a small portion of the zona fasciculata were perifused in vitro. The secretory responsiveness was assessed by measuring aldosterone and corticosterone release following stimulation with the physiological secretagogues ACTH and angiotensin II. The distribution of adrenal VIP receptors was assessed by in vitro autoradiography of {sup 125}I-VIP binding. {sup 125}I-VIP (0.75 and 2.0 nM) binding was concentrated in the capsule and zone glomerulosa, coincident with the distribution of VIP nerve fibers which aborize extensively in this region. The specificity of this binding was demonstrated using unlabelled VIP, ACTH and angiotensin II.

  10. Vasoactive intestinal peptide (VIP) induces malignant transformation of the human prostate epithelial cell line RWPE-1.

    PubMed

    Fernández-Martínez, Ana B; Bajo, Ana M; Isabel Arenas, M; Sánchez-Chapado, Manuel; Prieto, Juan C; Carmena, María J

    2010-12-18

    The carcinogenic potential of vasoactive intestinal peptide (VIP) was analyzed in non-tumor human prostate epithelial cells (RWPE-1) and in vivo xenografts. VIP induced morphological changes and a migratory phenotype consistent with stimulation of expression/activity of metalloproteinases MMP-2 and MMP-9, decreased E-cadherin-mediated cell-cell adhesion, and increased cell motility. VIP increased cyclin D1 expression and cell proliferation that was blocked after VPAC(1)-receptor siRNA transfection. Similar effects were seen in RWPE-1 tumors developed by subcutaneous injection of VIP-treated cells in athymic nude mice. VIP acts as a cytokine in RWPE-1 cell transformation conceivably through epithelial-mesenchymal transition (EMT), reinforcing VIP role in prostate tumorigenesis.

  11. Stimulation of mucosal secretion by lubiprostone (SPI-0211) in guinea pig small intestine and colon.

    PubMed

    Fei, Guijun; Wang, Yu-Zhong; Liu, Sumei; Hu, Hong-Zhen; Wang, Guo-Du; Qu, Mei-Hua; Wang, Xi-Yu; Xia, Yun; Sun, Xiaohong; Bohn, Laura M; Cooke, Helen J; Wood, Jackie D

    2009-04-01

    Actions of lubiprostone, a selective type-2 chloride channel activator, on mucosal secretion were investigated in guinea pig small intestine and colon. Flat-sheet preparations were mounted in Ussing flux chambers for recording short-circuit current (Isc) as a marker for electrogenic chloride secretion. Lubiprostone, applied to the small intestinal mucosa in eight concentrations ranging from 1-3000 nM, evoked increases in Isc in a concentration-dependent manner with an EC50 of 42.5 nM. Lubiprostone applied to the mucosa of the colon in eight concentrations ranging from 1-3000 nM evoked increases in Isc in a concentration-dependent manner with an EC50 of 31.7 nM. Blockade of enteric nerves by tetrodotoxin did not influence stimulation of Isc by lubiprostone. Antagonists acting at prostaglandin (PG)E2, EP1-3, or EP4 receptors did not suppress stimulation of Isc by lubiprostone but suppressed or abolished PGE2-evoked responses. Substitution of gluconate for chloride abolished all responses to lubiprostone. The selective CFTR channel blocker, CFTR(inh)-172, did not suppress lubiprostone-evoked Isc. The broadly acting blocker, glibenclamide, suppressed (P<0.001) lubiprostone-evoked Isc. Lubiprostone, in the presence of tetrodotoxin, enhanced carbachol-evoked Isc. The cholinergic component, but not the putative vasoactive intestinal peptide component, of neural responses to electrical field stimulation was enhanced by lubiprostone. Application of any of the prostaglandins, E2, F2, or I2, evoked depolarization of the resting membrane potential in enteric neurons. Unlike the prostaglandins, lubiprostone did not alter the electrical behavior of enteric neurons. Exposure to the histamine H2 receptor agonists increased basal Isc followed by persistent cyclical increases in Isc. Lubiprostone increased the peak amplitude of the dimaprit-evoked cycles.

  12. C-type natriuretic peptide stimulates ovarian follicle development.

    PubMed

    Sato, Yorino; Cheng, Yuan; Kawamura, Kazuhiro; Takae, Seido; Hsueh, Aaron J W

    2012-07-01

    C-type natriuretic peptide (CNP) encoded by the NPPC (Natriuretic Peptide Precursor C) gene expressed in ovarian granulosa cells inhibits oocyte maturation by activating the natriuretic peptide receptor (NPR)B (NPRB) in cumulus cells. RT-PCR analyses indicated increased NPPC and NPRB expression during ovarian development and follicle growth, associated with increases in ovarian CNP peptides in mice. In cultured somatic cells from infantile ovaries and granulosa cells from prepubertal animals, treatment with CNP stimulated cGMP production. Also, treatment of cultured preantral follicles with CNP stimulated follicle growth whereas treatment of cultured ovarian explants from infantile mice with CNP, similar to FSH, increased ovarian weight gain that was associated with the development of primary and early secondary follicles to the late secondary stage. Of interest, treatment with FSH increased levels of NPPC, but not NPRB, transcripts in ovarian explants. In vivo studies further indicated that daily injections of infantile mice with CNP for 4 d promoted ovarian growth, allowing successful ovulation induction by gonadotropins. In prepubertal mice, CNP treatment alone also promoted early antral follicle growth to the preovulatory stage, leading to efficient ovulation induction by LH/human chorionic gonadotropin. Mature oocytes retrieved after CNP treatment could be fertilized in vitro and developed into blastocysts, allowing the delivery of viable offspring. Thus, CNP secreted by growing follicles is capable of stimulating preantral and antral follicle growth. In place of FSH, CNP treatment could provide an alternative therapy for female infertility.

  13. IGF Binding Protein-4 is Required for the Growth Effects of Glucagon-Like Peptide-2 in Murine Intestine

    PubMed Central

    Austin, Kaori; Imam, Nuvair A.; Pintar, John E.

    2015-01-01

    Glucagon-like peptide-2 (GLP-2) is an enteroendocrine hormone that stimulates the growth of the intestinal epithelium. We have previously demonstrated that GLP-2 exerts its intestinotropic effect through an indirect mechanism that requires both IGF-1 and the intestinal epithelial IGF-1 receptor. However, the biological activity of IGF-1 is modulated by IGF binding proteins (IGFBPs), including IGFBP-4, which is highly expressed in the intestine. To determine the role of IGFBP-4 in the tropic effects of GLP-2, IGFBP-4 knockout (KO) and control mice were treated with degradation-resistant GLP-2 or vehicle for 10 days. Comparable levels of IGFBP-1–3/5–7 mRNAs were observed in the intestinal mucosa of all animals. IGFBP-4 KO mice had greater small intestinal weight and length, and deeper crypts (P < .05) as compared with controls, suggesting that IGFBP-4 has an inhibitory role in basal intestinal growth. However, small intestinal weight, crypt-villus height and crypt cell proliferation increased in response to GLP-2 in control mice (P < .05), and these changes were abrogated with IGFBP-4 KO. In contrast, pregnancy-associated plasma protein-A KO mice, which have increased levels of circulating IGFBP-4, demonstrated a normal intestinotropic response to GLP-2. Finally, GLP-2 treatment of control mice significantly increased IGFBP-4 mRNA expression in the jejunal mucosa (P < .05), a finding that was recapitulated by GLP-2 treatment of fetal rat intestinal cells in culture (10−8M for 2 h; P < .05). Collectively, these results indicate that the IGF-I-modulating protein, IGFBP-4, exerts a negative effect on basal intestinal growth but plays a positive regulatory role in the intestinotropic actions of GLP-2. PMID:25514089

  14. Glucagon like peptide-2 induces intestinal restitution through VEGF release from subepithelial myofibroblasts.

    PubMed

    Bulut, Kerem; Pennartz, Christian; Felderbauer, Peter; Meier, Juris J; Banasch, Matthias; Bulut, Daniel; Schmitz, Frank; Schmidt, Wolfgang E; Hoffmann, Peter

    2008-01-14

    Glucagon like peptide-2 (GLP-2) exerts intestinotrophic actions, but the underlying mechanisms are still a matter of debate. Recent studies demonstrated the expression of the GLP-2 receptor on fibroblasts located in the subepithelial tissue, where it might induce the release of growth factors such as keratinocyte growth factor (KGF) or vascular endothelial growth factor (VEGF). Therefore, in the present studies we sought to elucidate the downstream mechanisms involved in improved intestinal adaptation by GLP-2. Human colonic fibroblasts (CCD-18Co), human colonic cancer cells (Caco-2 cells) and rat ileum IEC-18 cells were used. GLP-2 receptor mRNA expression was determined using real time RT-PCR. Conditioned media from CCD-18Co cells were obtained following incubation with GLP-2 (50-250 nM) for 24 h. Cell viability was assessed by a 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium bromide (MTT)-assay, and wound healing was determined with an established migration-assay. Transforming Growth Factor beta (TGF-beta), VEGF and KGF mRNA levels were determined by RT-PCR. Protein levels of VEGF and TGF-beta in CCD-18Co cells following GLP-2 stimulation were determined using ELISA. Neutralizing TGF-beta and VEGF-A antibodies were utilized to assess the role of TGF-beta and VEGF-A in the process of wound healing. GLP-2 receptor expression was detected in CCD-18Co cells. Conditioned media from CCD-18Co cells dose-dependently induced proliferation in Caco-2 cells, but not in IEC-18 cells. Conditioned media also enhanced cell migration in IEC-18 cells (P<0.01), while migration was even inhibited in Caco-2 cells (P<0.0012). GLP-2 significantly stimulated mRNA expression of VEGF and TGF-beta, but not of KGF in CCD-18Co. The migratory effects of GLP-2 were completely abolished in the presence of TGF-beta and VEGF-A antibodies. GLP-2 exerts differential effects on the epithelium of the small intestine and the colon. Thus, in small intestinal cells GLP-2 stimulates wound

  15. Receptors for vasoactive intestinal peptide in rat anterior pituitary glands: Localization of binding to lactotropes

    SciTech Connect

    Wanke, I.E.; Rorstad, O.P. )

    1990-04-01

    Vasoactive intestinal peptide (VIP) has been implicated as a physiological PRL-releasing factor; however, characterization of VIP receptors on normal pituitaries using radioligand-binding methods has been problematic. In this study we demonstrated specific receptors for VIP in anterior pituitary glands of female rats using HPLC-purified monoiodinated (Tyr(125I)10)VIP. Binding of VIP was reversible, saturable to receptor and radioligand, regulated by guanine nucleotides, and dependent on time and temperature. Scatchard analysis of competitive binding studies indicated high and low affinity binding sites, with equilibrium dissociation constants (Kd) of 0.19 +/- 0.03 and 28 +/- 16 nM, respectively. The corresponding maximum numbers of binding sites were 158 +/- 34 fmol/mg and 11.7 +/- 6.9 pmol/mg. Binding was specific, as peptides with structural homology to VIP were less than 100th as potent as VIP. The rank order of potency of the peptides tested was VIP greater than rat (r) peptide histidine isoleucine = human (h) PHI greater than rGRF greater than bovine GRF = porcine PHI = VIP-(10-28) greater than hGRF greater than secretin greater than apamin greater than glucagon. Radioligand binding was associated primarily with lactotrope-enriched fractions prepared by unit gravity sedimentation of dispersed anterior pituitary cells. VIP stimulated PRL release from cultured rat anterior pituitary cells, with an ED50 of 1 nM. These results, comprising the first identification of specific VIP receptors in normal rat anterior pituitary tissue using radioligand-binding methods, provide additional support for a biological role of VIP in lactotrope function.

  16. Glucagon-like peptide-2 modulates neurally evoked mucosal chloride secretion in guinea pig small intestine in vitro

    PubMed Central

    Baldassano, Sara; Liu, Sumei; Qu, Mei-Hu; Mulè, Flavia

    2009-01-01

    Glucagon-like peptide-2 (GLP-2) is an important neuroendocrine peptide in intestinal physiology. It influences digestion, absorption, epithelial growth, motility, and blood flow. We studied involvement of GLP-2 in intestinal mucosal secretory behavior. Submucosal-mucosal preparations from guinea pig ileum were mounted in Ussing chambers for measurement of short-circuit current (Isc) as a surrogate for chloride secretion. GLP-2 action on neuronal release of acetylcholine was determined with ELISA. Enteric neuronal expression of the GLP-2 receptor (GLP-2R) was studied with immunohistochemical methods. Application of GLP-2 (0.1–100 nM) to the serosal or mucosal side of the preparations evoked no change in baseline Isc and did not alter transepithelial ionic conductance. Transmural electrical field stimulation (EFS) evoked characteristic biphasic increases in Isc, with an initially rapid rising phase followed by a sustained phase. Application of GLP-2 reduced the EFS-evoked biphasic responses in a concentration-dependent manner. The GLP-2R antagonist GLP-2-(3-33) significantly reversed suppression of the EFS-evoked responses by GLP-2. Tetrodotoxin, scopolamine, and hexamethonium, but not vasoactive intestinal peptide type 1 receptor (VPAC1) antagonist abolished or reduced to near zero the EFS-evoked responses. GLP-2 suppressed EFS-evoked acetylcholine release as measured by ELISA. Pretreatment with GLP-2-(3-33) offset this action of GLP-2. In the submucosal plexus, GLP-2R immunoreactivity (-IR) was expressed in choline acetyltransferase-IR neurons, somatostatin-IR neurons, neuropeptide Y-IR neurons, and vasoactive intestinal peptide-IR neurons. We conclude that submucosal neurons in the guinea pig ileum express GLP-2R. Activation of GLP-2R decreases neuronally evoked epithelial chloride secretion by suppressing acetylcholine release from secretomotor neurons. PMID:19628655

  17. Medicinal Plants Qua Glucagon-Like Peptide-1 Secretagogue via Intestinal Nutrient Sensors

    PubMed Central

    Kim, Ki-Suk; Jang, Hyeung-Jin

    2015-01-01

    Glucagon-like peptide-1 (GLP-1) participates in glucose homeostasis and feeding behavior. Because GLP-1 is rapidly inactivated by the enzymatic cleavage of dipeptidyl peptidase-4 (DPP4) long-acting GLP-1 analogues, for example, exenatide and DPP4 inhibitors, for example, liraglutide, have been developed as therapeutics for type 2 diabetes mellitus (T2DM). However, the inefficient clinical performance and the incidence of side effects reported on the existing therapeutics for T2DM have led to the development of a novel therapeutic strategy to stimulate endogenous GLP-1 secretion from enteroendocrine L cells. Since the GLP-1 secretion of enteroendocrine L cells depends on the luminal nutrient constituents, the intestinal nutrient sensors involved in GLP-1 secretion have been investigated. In particular, nutrient sensors for tastants, cannabinoids, and bile acids are able to recognize the nonnutritional chemical compounds, which are abundant in medicinal plants. These GLP-1 secretagogues derived from medicinal plants are easy to find in our surroundings, and their effectiveness has been demonstrated through traditional remedies. The finding of GLP-1 secretagogues is directly linked to understanding of the role of intestinal nutrient sensors and their recognizable nutrients. Concurrently, this study demonstrates the possibility of developing novel therapeutics for metabolic disorders such as T2DM and obesity using nutrients that are readily accessible in our surroundings. PMID:26788106

  18. Novel Association between Vasoactive Intestinal Peptide and CRTH2 Receptor in Recruiting Eosinophils

    PubMed Central

    El-Shazly, Amr E.; Begon, Dominique Y.; Kustermans, Gaelle; Arafa, Mohammad; Dortu, Estelle; Henket, Monique; Lefebvre, Philippe P.; Louis, Renaud; Delvenne, Philippe

    2013-01-01

    We explored the relation between vasoactive intestinal peptide (VIP), CRTH2, and eosinophil recruitment. It is shown that CRTH2 expression by eosinophils from allergic rhinitis (AR) patients and eosinophil cell line (Eol-1 cells) was up-regulated by VIP treatment. This was functional and resulted in exaggerated migratory response of cells against PGD2. Nasal challenge of AR patients resulted in a significant increase of VIP contents in nasal secretion (ELISA), and the immunohistochemical studies of allergic nasal tissues showed significant expression of VIP in association with intense eosinophil recruitment. Biochemical assays showed that VIP-induced eosinophil chemotaxis from AR patients and Eol-1 cells was mediated through the CRTH2 receptor. Cell migration against VIP was sensitive to protein kinase C (PKC) and protein kinase A (PKA) inhibition but not to tyrosine kinase or p38 MAPK inhibition or calcium chelation. Western blot demonstrated a novel CRTH2-mediated cytosol-to-membrane translocation of PKC-ϵ, PKC-δ, and PKA-α, -γ, and -IIαreg in Eol-1 cells upon stimulation with VIP. Confocal images and FACS demonstrated a strong association and co-localization between VIP peptide and CRTH2 molecules. Further, VIP induced PGD2 secretion from eosinophils. Our results demonstrate the first evidence of association between VIP and CRTH2 in recruiting eosinophils. PMID:23168411

  19. Acylation of Glucagon-Like Peptide-2: Interaction with Lipid Membranes and In Vitro Intestinal Permeability

    PubMed Central

    Trier, Sofie; Linderoth, Lars; Bjerregaard, Simon; Andresen, Thomas Lars; Rahbek, Ulrik Lytt

    2014-01-01

    Background Acylation of peptide drugs with fatty acid chains has proven beneficial for prolonging systemic circulation as well as increasing enzymatic stability without disrupting biological potency. Acylation has furthermore been shown to increase interactions with the lipid membranes of mammalian cells. The extent to which such interactions hinder or benefit delivery of acylated peptide drugs across cellular barriers such as the intestinal epithelia is currently unknown. The present study investigates the effect of acylating peptide drugs from a drug delivery perspective. Purpose We hypothesize that the membrane interaction is an important parameter for intestinal translocation, which may be used to optimize the acylation chain length for intestinal permeation. This work aims to characterize acylated analogues of the intestinotrophic Glucagon-like peptide-2 by systematically increasing acyl chain length, in order to elucidate its influence on membrane interaction and intestinal cell translocation in vitro. Results Peptide self-association and binding to both model lipid and cell membranes was found to increase gradually with acyl chain length, whereas translocation across Caco-2 cells depended non-linearly on chain length. Short and medium acyl chains increased translocation compared to the native peptide, but long chain acylation displayed no improvement in translocation. Co-administration of a paracellular absorption enhancer was found to increase translocation irrespective of acyl chain length, whereas a transcellular enhancer displayed increased synergy with the long chain acylation. Conclusions These results show that membrane interactions play a prominent role during intestinal translocation of an acylated peptide. Acylation benefits permeation for shorter and medium chains due to increased membrane interactions, however, for longer chains insertion in the membrane becomes dominant and hinders translocation, i.e. the peptides get ‘stuck’ in the cell

  20. Vasoactive intestinal peptide, a promising agent for myopia?

    PubMed Central

    Cakmak, Ayse Idil; Basmak, Hikmet; Gursoy, Huseyin; Ozkurt, Mete; Yildirim, Nilgun; Erkasap, Nilufer; Bilgec, Mustafa Deger; Tuncel, Nese; Colak, Ertugrul

    2017-01-01

    AIM To investigate the role of vasoactive intestinal peptide (VIP) in form-deprivation myopia (FDM). METHODS FDM was created in three groups of eight chicks by placing a translucent diffuser on their right eyes. Intravitreal injections of saline and VIP were applied once a day into the occluded eyes of groups 2 and 3, respectively. Retinoscopy and axial length (AL) measurements were performed on the first and 8th days of diffuser wear. The retina mRNA levels of the VIP receptors and the ZENK protein in right eyes of the three groups and left eyes of the first group on day 8 were determined using real time polymerase chain reaction (PCR). RESULTS The median final refraction (D) in right eyes were -13.75 (-16.00, -12.00), -11.50 (-12.50, -7.50), and -1.50 (-4.75, -0.75) in groups 1, 2, and 3, respectively (P<0.001). The median AL (mm) in right eyes were 10.65 (10.00, 11.10), 9.90 (9.70, 10.00), and 9.20 (9.15, 9.25) in groups 1, 2, and 3, respectively (P<0.001). The median delta-delta cycle threshold (CT) values for the VIP2 receptors were 1.07 (0.82, 1.43), 1.22 (0.98, 1.65), 0.29 (0.22, 0.45) in right eyes of groups 1, 2, and 3, and 1.18 (0.90, 1.37) in left eyes of group 1, respectively (P=0.001). The median delta-delta CT values for the ZENK protein were 1.07 (0.63, 5.03), 3.55 (2.20, 5.55), undetectable in right eyes of groups 1, 2, and 3 and 1.89 (0.21, 4.73) in left eyes of group 1, respectively (P=0.001). CONCLUSION VIP has potential inhibitory effects in the development of FDM. PMID:28251078

  1. Intestinal cell targeting of a stable recombinant Cu-Zn SOD from Cucumis melo fused to a gliadin peptide.

    PubMed

    Intes, Laurent; Bahut, Muriel; Nicole, Pascal; Couvineau, Alain; Guette, Catherine; Calenda, Alphonse

    2012-05-31

    The mRNA encoding full length chloroplastic Cu-Zn SOD (superoxide dismutase) of Cucumis melo (Cantaloupe melon) was cloned. This sequence was then used to generate a mature recombinant SOD by deleting the first 64 codons expected to encode a chloroplastic peptide signal. A second hybrid SOD was created by inserting ten codons to encode a gliadin peptide at the N-terminal end of the mature SOD. Taking account of codon bias, both recombinant proteins were successfully expressed and produced in Escherichia coli. Both recombinant SODs display an enzymatic activity of ~5000U mg(-1) and were shown to be stable for at least 4h at 37°C in biological fluids mimicking the conditions of intestinal transit. These recombinant proteins were capable in vitro, albeit at different levels, of reducing ROS-induced-apoptosis of human epithelial cells. They also stimulated production and release in a time-dependent manner of an autologous SOD activity from cells located into jejunum biopsies. Nevertheless, the fused gliadin peptide enable the recombinant Cu-Zn SOD to maintain a sufficiently sustained interaction with the intestinal cells membrane in vivo rather than being eliminated with the flow. According to these observations, the new hybrid Cu-Zn SOD should show promise in applications for managing inflammatory bowel diseases.

  2. Vagal nerve stimulation protects against burn-induced intestinal injury through activation of enteric glia cells

    PubMed Central

    Costantini, Todd W.; Bansal, Vishal; Krzyzaniak, Michael; Putnam, James G.; Peterson, Carrie Y.; Loomis, William H.; Wolf, Paul; Baird, Andrew; Eliceiri, Brian P.

    2010-01-01

    The enteric nervous system may have an important role in modulating gastrointestinal barrier response to disease through activation of enteric glia cells. In vitro studies have shown that enteric glia activation improves intestinal epithelial barrier function by altering the expression of tight junction proteins. We hypothesized that severe injury would increase expression of glial fibrillary acidic protein (GFAP), a marker of enteric glial activation. We also sought to define the effects of vagal nerve stimulation on enteric glia activation and intestinal barrier function using a model of systemic injury and local gut mucosal involvement. Mice with 30% total body surface area steam burn were used as model of severe injury. Vagal nerve stimulation was performed to assess the role of parasympathetic signaling on enteric glia activation. In vivo intestinal permeability was measured to assess barrier function. Intestine was collected to investigate changes in histology; GFAP expression was assessed by quantitative PCR, by confocal microscopy, and in GFAP-luciferase transgenic mice. Stimulation of the vagus nerve prevented injury-induced intestinal barrier injury. Intestinal GFAP expression increased at early time points following burn and returned to baseline by 24 h after injury. Vagal nerve stimulation prior to injury increased GFAP expression to a greater degree than burn alone. Gastrointestinal bioluminescence was imaged in GFAP-luciferase transgenic animals following either severe burn or vagal stimulation and confirmed the increased expression of intestinal GFAP. Injection of S-nitrosoglutathione, a signaling molecule released by activated enteric glia cells, following burn exerts protective effects similar to vagal nerve stimulation. Intestinal expression of GFAP increases following severe burn injury. Stimulation of the vagus nerve increases enteric glia activation, which is associated with improved intestinal barrier function. The vagus nerve may mediate the

  3. Phorbol esters alter adenylate cyclase responses to vasoactive intestinal peptide and forskolin in the GH cell line

    SciTech Connect

    Summers, S.; Florio, T.; Cronin, M.

    1986-05-01

    Activation of protein kinase C with phorbol ester modifies cyclic AMP production in several anterior pituitary cell systems. In the GH cell line from a rat pituitary tumor, exposure to phorbol 12-myristate 13-acetate (PMA: 100 nM) for 30 minutes significantly reduces vasoactive intestinal peptide (VIP: 100 nM) stimulated adenylate cyclase (AC) activity in subsequent membrane preparations to 62 + 4% of control (n = 6 independent studies). In contrast, these same membrane preparations respond to forskolin (1 ..mu..M) with significantly more activity, 130 +/- 6% of controls (n = 6 independent studies). Finally, phorbol ester does not block an inhibitory hormone input into the AC system; somatostatin (100 nM) reduction of VIP-stimulated AC activity is not significantly different in membrane preparations from PMA treated and control cells (n = 3 independent studies). These other findings lead the authors to propose that protein kinase C can modify several sites in the AC complex in anterior pituitary cells.

  4. Gastrin-releasing peptide stimulates glycoconjugate release from feline trachea

    SciTech Connect

    Lundgren, J.D.; Baraniuk, J.N.; Ostrowski, N.L.; Kaliner, M.A.; Shelhamer, J.H. )

    1990-02-01

    The effect of gastrin-releasing peptide (GRP) on respiratory glycoconjugate (RGC) secretion was investigated in a feline tracheal organ culture model. RGC secretion was stimulated by GRP in a dose-dependent fashion at concentrations from 10(-8) to 10(-5) M (range 15-38% increase above control) with a peak effect within 0.5-1 h of incubation. GRP-(14-27), the receptor binding portion of GRP, and the related molecule, bombesin, also stimulated RGC secretion by approximately 20% above control. Acetyl-GRP-(20-27) stimulated RGC release by 10%, whereas GRP-(1-16) was inactive. Autoradiographic studies with 125I-GRP revealed that specific binding was restricted to the submucosal glands and the surface epithelium. A specific radioimmunoassay showed the content of GRP in feline trachea after extraction with ethanol-acetic acid to be 156 +/- 91 fmol/g wet wt. Indirect immunohistochemistry indicated that ganglion cells located just outside the cartilage contained GRP-immunoreactive materials. GRP is a novel mucus secretagogue that may participate in regulating airway mucosal gland secretion.

  5. Flavonoids stimulate cholecystokinin peptide secretion from the enteroendocrine STC-1 cells.

    PubMed

    Al Shukor, Nadin; Ravallec, Rozenn; Van Camp, John; Raes, Katleen; Smagghe, Guy

    2016-09-01

    Animal experiments showed that flavonoids might have the potential for an anti-obesity effect by reducing weight and food intake. However, the exact mechanisms that could be involved in these proposed effects are still under investigation. The complex process of food intake is partially regulated by gastrointestinal hormones. Cholecystokinin (CCK) is the best known gastrointestinal hormone to induce satiety signal that plays a key role in food intake regulation. It is released from the endocrine cells (I cell) in response to the ingestion of nutrients into the small intestine. In this study, we investigated the possible effects of flavonoids (quercetin, kaempferol, apigenin, rutin and baicalein) on stimulation of CCK release in vitro using enteroendocrine STC-1 cells. In comparison with the control, quercetin, kaempferol and apigenin resulted in a significant increase in CCK secretion with quercetin showing the highest activity. On the other hand, no significant effect was seen by rutin and baicalein. To our knowledge, this is the first report to study the stimulation of CCK peptide hormone secretion from STC-1 cells by quercetin and kaempferol, rutin, apigenin and baicalein. Based on the cell-based results in this work, it can be suggested that the reported activity of flavonoids against food intake and weight could be mediated by stimulation of CCK signal which in turn is responsible for food intake reduction, but future animal and human studies are needed to confirm this conclusion at organism level.

  6. Intestinal Permeability and Glucagon-Like Peptide-2 in Children with Autism: A Controlled Pilot Study

    ERIC Educational Resources Information Center

    Robertson, Marli A.; Sigalet, David L.; Holst, Jens J.; Meddings, Jon B.; Wood, Julie; Sharkey, Keith A.

    2008-01-01

    We measured small intestinal permeability using a lactulose:mannitol sugar permeability test in a group of children with autism, with current or previous gastrointestinal complaints. Secondly, we examined whether children with autism had an abnormal glucagon-like peptide-2 (GLP-2) response to feeding. Results were compared with sibling controls…

  7. Lanthanide-stimulated glucose and proline transport across rabbit intestinal brush-border membranes.

    PubMed

    Stevens, B R; Kneer, C

    1988-07-07

    Trivalent cations of the lanthanide series (La3+----Yb3+) stimulated uptake of proline or glucose in rabbit small intestinal brush-border membrane vesicles. The lanthanides stimulated uptake to an extent greater than Al3+, choline, and in many cases, Na+. A time-course of Er3+-stimulated glucose uptake gave initial rates and overshoots greater than Na+ stimulation. The best activators were Sm3+, Eu3+ and Tm3+, which stimulated proline initial uptakes by 400-600%, and stimulated glucose uptake by 120-150%, compared to Na+. The best lanthanide cotransport activators possessed high third ionization potentials.

  8. Acylation of salmon calcitonin modulates in vitro intestinal peptide flux through membrane permeability enhancement.

    PubMed

    Trier, Sofie; Linderoth, Lars; Bjerregaard, Simon; Strauss, Holger M; Rahbek, Ulrik L; Andresen, Thomas L

    2015-10-01

    Acylation of peptide drugs with fatty acid chains has proven beneficial for prolonging systemic circulation, as well as increasing enzymatic stability and interactions with lipid cell membranes. Thus, acylation offers several potential benefits for oral delivery of therapeutic peptides, and we hypothesize that tailoring the acylation may be used to optimize intestinal translocation. This work aims to characterize acylated analogues of the therapeutic peptide salmon calcitonin (sCT), which lowers blood calcium, by systematically increasing acyl chain length at two positions, in order to elucidate its influence on intestinal cell translocation and membrane interaction. We find that acylation drastically increases in vitro intestinal peptide flux and confers a transient permeability enhancing effect on the cell layer. The analogues permeabilize model lipid membranes, indicating that the effect is due to a solubilization of the cell membrane, similar to transcellular oral permeation enhancers. The effect is dependent on pH, with larger effect at lower pH, and is impacted by acylation chain length and position. Compared to the unacylated peptide backbone, N-terminal acylation with a short chain provides 6- or 9-fold increase in peptide translocation at pH 7.4 and 5.5, respectively. Prolonging the chain length appears to hamper translocation, possibly due to self-association or aggregation, although the long chain acylated analogues remain superior to the unacylated peptide. For K(18)-acylation a short chain provides a moderate improvement, whereas medium and long chain analogues are highly efficient, with a 12-fold increase in permeability compared to the unacylated peptide backbone, on par with currently employed oral permeation enhancers. For K(18)-acylation the medium chain acylation appears to be optimal, as elongating the chain causes greater binding to the cell membrane but similar permeability, and we speculate that increasing the chain length further may

  9. Glucagon-like peptide-2 induces rapid digestive adaptation following intestinal resection in preterm neonates

    PubMed Central

    Vegge, Andreas; Thymann, Thomas; Lund, Pernille; Stoll, Barbara; Bering, Stine B.; Hartmann, Bolette; Jelsing, Jacob; Qvist, Niels; Burrin, Douglas G.; Jeppesen, Palle B.; Holst, Jens J.

    2013-01-01

    Short bowel syndrome (SBS) is a frequent complication after intestinal resection in infants suffering from intestinal disease. We tested whether treatment with the intestinotrophic hormone glucagon-like peptide-2 (GLP-2) increases intestinal volume and function in the period immediately following intestinal resection in preterm pigs. Preterm pigs were fed enterally for 48 h before undergoing resection of 50% of the small intestine and establishment of a jejunostomy. Following resection, pigs were maintained on total parenteral nutrition (TPN) without (SBS, n = 8) or with GLP-2 treatment (3.5 μg/kg body wt per h, SBS+GLP-2, n = 7) and compared with a group of unresected preterm pigs (control, n = 5). After 5 days of TPN, all piglets were fed enterally for 24 h, and a nutrient balance study was performed. Intestinal resection was associated with markedly reduced endogenous GLP-2 levels. GLP-2 increased the relative absorption of wet weight (46 vs. 22%), energy (79 vs. 64%), and all macronutrients (all parameters P < 0.05). These findings were supported by a 200% increase in sucrase and maltase activities, a 50% increase in small intestinal epithelial volume (P < 0.05), as well as increased DNA and protein contents and increased total protein synthesis rate in SBS+GLP-2 vs. SBS pigs (+100%, P < 0.05). Following intestinal resection in preterm pigs, GLP-2 induced structural and functional adaptation, resulting in a higher relative absorption of fluid and macronutrients. GLP-2 treatment may be a promising therapy to enhance intestinal adaptation and improve digestive function in preterm infants with jejunostomy following intestinal resection. PMID:23764891

  10. Mesenchymal stem cells stimulate intestinal stem cells to repair radiation-induced intestinal injury

    PubMed Central

    Gong, Wei; Guo, Mengzheng; Han, Zhibo; Wang, Yan; Yang, Ping; Xu, Chang; Wang, Qin; Du, Liqing; Li, Qian; Zhao, Hui; Fan, Feiyue; Liu, Qiang

    2016-01-01

    The loss of stem cells residing in the base of the intestinal crypt has a key role in radiation-induced intestinal injury. In particular, Lgr5+ intestinal stem cells (ISCs) are indispensable for intestinal regeneration following exposure to radiation. Mesenchymal stem cells (MSCs) have previously been shown to improve intestinal epithelial repair in a mouse model of radiation injury, and, therefore, it was hypothesized that this protective effect is related to Lgr5+ ISCs. In this study, it was found that, following exposure to radiation, transplantation of MSCs improved the survival of the mice, ameliorated intestinal injury and increased the number of regenerating crypts. Furthermore, there was a significant increase in Lgr5+ ISCs and their daughter cells, including Ki67+ transient amplifying cells, Vil1+ enterocytes and lysozyme+ Paneth cells, in response to treatment with MSCs. Crypts isolated from mice treated with MSCs formed a higher number of and larger enteroids than those from the PBS group. MSC transplantation also reduced the number of apoptotic cells within the small intestine at 6 h post-radiation. Interestingly, Wnt3a and active β-catenin protein levels were increased in the small intestines of MSC-treated mice. In addition, intravenous delivery of recombinant mouse Wnt3a after radiation reduced damage in the small intestine and was radioprotective, although not to the same degree as MSC treatment. Our results show that MSCs support the growth of endogenous Lgr5+ ISCs, thus promoting repair of the small intestine following exposure to radiation. The molecular mechanism of action mediating this was found to be related to increased activation of the Wnt/β-catenin signaling pathway. PMID:27685631

  11. Novel GM1 ganglioside-like peptide mimics prevent the association of cholera toxin to human intestinal epithelial cells in vitro.

    PubMed

    Yu, Robert K; Usuki, Seigo; Itokazu, Yutaka; Wu, Han-Chung

    2016-01-01

    Cholera is an acute diarrheal disease caused by infection in the gastrointestinal tract by the gram-negative bacterium, Vibrio cholerae, and is a serious public health threat worldwide. There has not been any effective treatment for this infectious disease. Cholera toxin (CT), which is secreted by V. cholerae, can enter host cells by binding to GM1, a monosialoganglioside widely distributed on the plasma membrane surface of various animal epithelial cells. The present study was undertaken to generate peptides that are conformationally similar to the carbohydrate epitope of GM1 for use in the treatment of cholera and related bacterial infection. For this purpose, we used cholera toxin B (CTB) subunit to select CTB-binding peptides that structurally mimic GM1 from a dodecamer phage-display library. Six GM1-replica peptides were selected by biopanning based on CTB recognition. Five of the six peptides showed inhibitory activity for GM1 binding to CTB. To test the potential of employing the peptide mimics for intervening with the bacterial infection, those peptides were examined for their binding capacity, functional inhibitory activity and in vitro effects using a human intestinal epithelial cell line, Caco-2 cells. One of the peptides, P3 (IPQVWRDWFKLP), was most effective in inhibiting cellular uptake of CTB and suppressing CT-stimulated cyclic adenosine monophosphate production in the cells. Our results thus provide convincing evidence that GM1-replica peptides could serve as novel agents to block CTB binding on epithelial cells and prevent the ensuing physiological effects of CT.

  12. Intestinotrophic Glucagon-Like Peptide-2 (GLP-2) Activates Intestinal Gene Expression and Growth Factor-Dependent Pathways Independent of the Vasoactive Intestinal Peptide Gene in Mice

    PubMed Central

    Yusta, Bernardo; Holland, Dianne; Waschek, James A.

    2012-01-01

    The enteroendocrine and enteric nervous systems convey signals through an overlapping network of regulatory peptides that act either as circulating hormones or as localized neurotransmitters within the gastrointestinal tract. Because recent studies invoke an important role for vasoactive intestinal peptide (VIP) as a downstream mediator of glucagon-like peptide-2 (GLP-2) action in the gut, we examined the importance of the VIP-GLP-2 interaction through analysis of Vip−/− mice. Unexpectedly, we detected abnormal villous architecture, expansion of the crypt compartment, increased crypt cell proliferation, enhanced Igf1 and Kgf gene expression, and reduced expression of Paneth cell products in the Vip−/− small bowel. These abnormalities were not reproduced by antagonizing VIP action in wild-type mice, and VIP administration did not reverse the intestinal phenotype of Vip−/− mice. Exogenous administration of GLP-2 induced the expression of ErbB ligands and immediate-early genes to similar levels in Vip+/+ vs. Vip−/− mice. Moreover, GLP-2 significantly increased crypt cell proliferation and small bowel growth to comparable levels in Vip+/+ vs. Vip−/− mice. Unexpectedly, exogenous GLP-2 administration had no therapeutic effect in mice with dextran sulfate-induced colitis; the severity of colonic injury and weight loss was modestly reduced in female but not male Vip−/− mice. Taken together, these findings extend our understanding of the complex intestinal phenotype arising from loss of the Vip gene. Furthermore, although VIP action may be important for the antiinflammatory actions of GLP-2, the Vip gene is not required for induction of a gene expression program linked to small bowel growth after enhancement of GLP-2 receptor signaling. PMID:22535770

  13. Determination of the optimal cell-penetrating peptide sequence for intestinal insulin delivery based on molecular orbital analysis with self-organizing maps.

    PubMed

    Kamei, Noriyasu; Kikuchi, Shingo; Takeda-Morishita, Mariko; Terasawa, Yoshiaki; Yasuda, Akihito; Yamamoto, Shuichi; Ida, Nobuo; Nishio, Reiji; Takayama, Kozo

    2013-02-01

    Our recent work has shown that the intestinal absorption of insulin can be improved significantly by coadministration of cell-penetrating peptides (CPPs), especially penetratin. However, a relatively high dose of penetratin is required to adequately stimulate the intestinal absorption of insulin. Therefore, in this study, we sought to determine the CPP that most effectively enhanced intestinal insulin absorption. An in situ loop absorption study using 26 penetratin analogues suggested that the chain length, hydrophobicity, and amphipathicity of the CPPs, as well as their basicity, contribute to their absorption-enhancing efficiency. Moreover, a molecular orbital method with self-organizing maps (SOMs) classification suggested that multiple factors, including the molecular weight, basicity, the lowest unoccupied molecular orbital energy, absolute hardness, and chemical potential of CPPs, are associated with their effects on intestinal insulin absorption. Furthermore, the new CPPs proposed by SOM clustering had a marked capacity to interact with insulin, and their ability to enhance insulin absorption was much stronger than that of the original penetratin. Therefore, the peptide sequence that optimally enhances intestinal insulin absorption could be defined by SOM with the molecular orbital method, and our present work emphasizes the utility of such methodologies in the development of effective drug delivery systems.

  14. Antimicrobial peptide scolopendrasin VII, derived from the centipede Scolopendra subspinipes mutilans, stimulates macrophage chemotaxis via formyl peptide receptor 1.

    PubMed

    Park, Yoo Jung; Lee, Ha Young; Jung, Young Su; Park, Joon Seong; Hwang, Jae Sam; Bae, Yoe-Sik

    2015-08-01

    In this study, we report that one of the antimicrobial peptides scolopendrasin VII, derived from Scolopendra subspinipes mutilans, stimulates actin polymerization and the subsequent chemotactic migration of macrophages through the activation of ERK and protein kinase B (Akt) activity. The scolopendrasin VII-induced chemotactic migration of macrophages is inhibited by the formyl peptide receptor 1 (FPR1) antagonist cyclosporine H. We also found that scolopendrasin VII stimulate the chemotactic migration of FPR1-transfected RBL-2H3 cells, but not that of vector-transfected cells; moreover, scolopendrasin VII directly binds to FPR1. Our findings therefore suggest that the antimicrobial peptide scolopendrasin VII, derived from Scolopendra subspinipes mutilans, stimulates macrophages, resulting in chemotactic migration via FPR1 signaling, and the peptide can be useful in the study of FPR1-related biological responses.

  15. A selective inhibitor of intestinal ACAT, EAB309 suppresses both intestinal and hepatic cholesterol output and stimulates chylomicron removal.

    PubMed

    Umeda, Y; Hirano, T; Kako, Y; Kamagata, K; Okuyama, K; Suzuki, K

    1998-01-01

    The effect of a novel inhibitor of acylcoenzyme A:cholesterol acyltransferase (EC 2.3.1.26, ACAT), EAB309 (EAB) on plasma lipid metabolism was studied in cholesterol-fed rats. Orally administered EAB was not detected in the portal vein or the liver but distributed exclusively in the intestine, suggesting that this agent selectively inhibits intestinal ACAT. The rats were fed with either a cholesterol-diet or a cholesterol-diet containing 0.005% EAB (w/w) ad. libium for three weeks. ACAT activity in intestinal microsomes was significantly inhibited in EAB-treated rats. Hepatic ACAT activity was also decreased in EAB-treated rats, however, this was attenuated by the addition of excess cholesterol to the liver microsome, indicating that substrate availability is tightly associated with this enzyme's activity and the inhibition of hepatic ACAT by EAB is not direct. Incorporation of [3H]-cholesterol to cholesteryl ester (CE) in mesenteric lymph were markedly suppressed by EAB treatment. Chylomicrons (CMs) were doubly labeled with [3H]-vitamin A and [14C]-triglyceride (TG) in EAB-treated or non-treated rats and injected into normal chow-fed rats. The CMs from EAB-treated rats were cleared faster from the plasma and taken up more by the liver compared with the CMs from non-treated rats. The content of CE in newly secreted VLDL was remarkably decreased by EAB treatment without affecting TG output. These results demonstrate that EAB, a novel inhibitor of intestinal ACAT, significantly suppresses both intestinal and hepatic CE output and stimulates CM removal. This suggests that the inhibition of intestinal ACAT can subsequently suppress hepatic ACAT by decreased CE delivery from the intestine to the liver.

  16. Stimulation of intestinal growth and function with DPP4 inhibition in a mouse short bowel syndrome model.

    PubMed

    Sueyoshi, Ryo; Woods Ignatoski, Kathleen M; Okawada, Manabu; Hartmann, Bolette; Holst, Jens; Teitelbaum, Daniel H

    2014-08-15

    Glucagon-like peptide-2 (GLP-2) has been shown to be effective in patients with short bowel syndrome (SBS), but it is rapidly inactivated by dipeptidyl peptidase IV (DPP4). We used an orally active DPP4 inhibitor (DPP4-I), MK-0626, to determine the efficacy of this approach to promote adaptation after SBS, determined optimal dosing, and identified further functional actions in a mouse model of SBS. Ten-week-old mice underwent a 50% proximal small bowel resection. Dose optimization was determined over a 3-day post-small bowel resection period. The established optimal dose was given for 7, 30, and 90 days and for 7 days followed by a 23-day washout period. Adaptive response was assessed by morphology, intestinal epithelial cell (IEC) proliferation (proliferating cell nuclear antigen), epithelial barrier function (transepithelial resistance), RT-PCR for intestinal transport proteins and GLP-2 receptor, IGF type 1 receptor, and GLP-2 plasma levels. Glucose-stimulated sodium transport was assessed for intestinal absorptive function. Seven days of DPP4-I treatment facilitated an increase in GLP-2 receptor levels, intestinal growth, and IEC proliferation. Treatment led to differential effects over time, with greater absorptive function at early time points and enhanced proliferation at later time points. Interestingly, adaptation continued in the group treated for 7 days followed by a 23-day washout. DPP4-I enhanced IEC proliferative action up to 90 days postresection, but this action seemed to peak by 30 days, as did GLP-2 plasma levels. Thus DPP4-I treatment may prove to be a viable option for accelerating intestinal adaptation with SBS.

  17. Fat digestion is required for suppression of ghrelin and stimulation of peptide YY and pancreatic polypeptide secretion by intraduodenal lipid.

    PubMed

    Feinle-Bisset, Christine; Patterson, Michael; Ghatei, Mohammad A; Bloom, Stephen R; Horowitz, Michael

    2005-12-01

    Stimulation of cholecystokinin and glucagon-like peptide-1 secretion by fat is mediated by the products of fat digestion. Ghrelin, peptide YY (PYY), and pancreatic polypeptide (PP) appear to play an important role in appetite regulation, and their release is modulated by food ingestion, including fat. It is unknown whether fat digestion is a prerequisite for their suppression (ghrelin) or release (PYY, PP). Moreover, it is not known whether small intestinal exposure to fat is sufficient to suppress ghrelin secretion. Our study aimed to resolve these issues. Sixteen healthy young males received, on two separate occasions, 120-min intraduodenal infusions of a long-chain triglyceride emulsion (2.8 kcal/min) 1) without (condition FAT) or 2) with (FAT-THL) 120 mg of tetrahydrolipstatin (THL, lipase inhibitor), followed by a standard buffet-style meal. Blood samples for ghrelin, PYY, and PP were taken throughout. FAT infusion was associated with a marked, and progressive, suppression of plasma ghrelin from t = 60 min (P < 0.001) and stimulation of PYY from t = 30 min (P < 0.01). FAT infusion also stimulated plasma PP (P < or = 0.01), and the release was immediate. FAT-THL completely abolished the FAT-induced changes in ghrelin, PYY, and PP. In response to the meal, plasma ghrelin was further suppressed, and PYY and PP stimulated, during both FAT and FAT-THL infusions. In conclusion, in healthy humans, 1) the presence of fat in the small intestine suppresses ghrelin secretion, and 2) fat-induced suppression of ghrelin and stimulation of PYY and PP is dependent on fat digestion.

  18. Vasoactive Intestinal Peptide Inhibits Human Small-Cell Lung Cancer Proliferation in vitro and in vivo

    NASA Astrophysics Data System (ADS)

    Maruno, Kaname; Absood, Afaf; Said, Sami I.

    1998-11-01

    Small-cell lung carcinoma (SCLC) is an aggressive, rapidly growing and metastasizing, and highly fatal neoplasm. We report that vasoactive intestinal peptide inhibits the proliferation of SCLC cells in culture and dramatically suppresses the growth of SCLC tumor-cell implants in athymic nude mice. In both cases, the inhibition was mediated apparently by a cAMP-dependent mechanism, because the inhibition was enhanced by the adenylate cyclase activator forskolin and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine in proportion to increases in intracellular cAMP levels, and the inhibition was abolished by selective inhibition of cAMP-dependent protein kinase. If confirmed in clinical trials, this antiproliferative action of vasoactive intestinal peptide may offer a new and promising means of suppressing SCLC in human subjects, without the toxic side effects of chemotherapeutic agents.

  19. Effects of cysteamine supplementation on the intestinal expression of amino acid and peptide transporters and intestinal health in finishing pigs.

    PubMed

    Zhou, Ping; Luo, Yiqiu; Zhang, Lin; Li, Jiaolong; Zhang, Bolin; Xing, Shen; Zhu, Yuping; Gao, Feng; Zhou, Guanghong

    2017-02-01

    This study aimed to evaluate the effects of cysteamine supplementation on the expression of jejunal amino acid and peptide transporters and intestinal health in finishing pigs. Sixty barrows were allocated into two experimental diets consisting of a basal control diet supplemented with 0 or 142 mg/kg cysteamine. After 41 days, 10 pigs per treatment were slaughtered. The results showed that cysteamine supplementation increased the apparent digestibility of crude protein (CP) (P < 0.05) and the trypsin activity in jejunal digesta (P < 0.01). Cysteamine supplementation also increased the messenger RNA abundance of SLC7A7, SLC7A9 and SLC15A1, occludin, claudin-1 and zonula occludens protein-1 (P < 0.001) in the jejunum mucosa. Increased glutathione content (P < 0.01) and glutathione peroxidase activity (P < 0.05) and decreased malondialdehyde content (P < 0.01) were observed in pigs receiving cysteamine. Additionally, cysteamine supplementation increased the concentrations of secretory immunoglobulin A (IgA) (P < 0.05), IgM (P < 0.001) and IgG (P < 0.001) in the jejunal mucosa. It is concluded that cysteamine supplementation could influence protein digestion and absorption via increasing trypsin activity, enhancing the digestibility of CP, and promoting the expression of jejunal amino acid and peptide transporters. Moreover, cysteamine improved intestinal integrity, antioxidant capacity and immune function in the jejunum, which were beneficial for intestinal health.

  20. Helical synthetic peptides that stimulate cellular cholesterol efflux

    DOEpatents

    Bielicki, John K.; Natarajan, Pradeep

    2010-04-06

    The present invention provides peptides comprising at least one amphipathic alpha helix and having an cholesterol mediating activity and a ABCA stabilization activity. The invention further provides methods of using such peptides.

  1. Glucagon-like peptide-2 protects impaired intestinal mucosal barriers in obstructive jaundice rats

    PubMed Central

    Chen, Jun; Dong, Jia-Tian; Li, Xiao-Jing; Gu, Ye; Cheng, Zhi-Jian; Cai, Yuan-Kun

    2015-01-01

    AIM: To observe the protective effect of glucagon-like peptide-2 (GLP-2) on the intestinal barrier of rats with obstructive jaundice and determine the possible mechanisms of action involved in the protective effect. METHODS: Thirty-six Sprague-Dawley rats were randomly divided into a sham operation group, an obstructive jaundice group, and a GLP-2 group; each group consisted of 12 rats. The GLP-2 group was treated with GLP-2 after the day of surgery, whereas the other two groups were treated with the same concentration of normal saline. Alanine aminotransferase (ALT), total bilirubin, and endotoxin levels were recorded at 1, 3, 7, 10 and 14 d. Furthermore, on the 14th day, body weight, the wet weight of the small intestine, pathological changes of the small intestine and the immunoglobulin A (IgA) expressed by plasma cells located in the small intestinal lamina propria were recorded for each group. RESULTS: In the rat model, jaundice was obvious, and the rats’ activity decreased 4-6 d post bile duct ligation. Compared with the sham operation group, the obstructive jaundice group displayed increased yellow staining of abdominal visceral serosa, decreased small intestine wet weight, thinning of the intestinal muscle layer and villi, villous atrophy, uneven height, fusion, partial villous epithelial cell shedding, substantial inflammatory cell infiltration and significantly reduced IgA expression. However, no significant gross changes were noted between the GLP-2 and sham groups. With time, the levels of ALT, endotoxin and bilirubin in the GLP-2 group were significantly increased compared with the sham group (P < 0.01). The increasing levels of the aforementioned markers were more significant in the obstructive jaundice group than in the GLP-2 group (P < 0.01). CONCLUSION: GLP-2 reduces intestinal mucosal injuries in obstructive jaundice rats, which might be attributed to increased intestinal IgA and reduced bilirubin and endotoxin. PMID:25593463

  2. Natriuretic peptides stimulate oocyte meiotic resumption in bovine.

    PubMed

    De Cesaro, Matheus P; Macedo, Mariana P; Santos, Joabel T; Rosa, Paulo R A; Ludke, Charles A; Rissi, Vitor B; Gasperin, Bernardo G; Gonçalves, Paulo B D

    2015-08-01

    The aim of the present study was to evaluate the expression of mRNA encoding natriuretic peptides (NPs) and their receptors in the cumulus-oocyte complex in cattle, a monovular mammalian species, and also to investigate the role of NPs in oocyte meiotic resumption in vitro. mRNA was observed for the NP precursor type-A (NPPA), type-C (NPPC), NP receptor-1 (NPR-1), receptor-2 (NPR-2) and receptor-3 (NPR-3) in bovine cumulus cells, and NPR-2 mRNA was observed in oocytes. These results are different from those obtained in mouse and pig models. The effects of NPPA, NP precursor type-B (NPPB) and NPPC on the resumption of arrested meiosis maintained by forskolin were studied at three different doses (10, 100 and 1000nM) with a 12h culture system. The germinal vesicle breakdown rates were greater (P≤0.05) in oocytes that were cultured in the presence of one or a combination of NPs (from 44% to 73%) than the negative control (from 24% to 27%). Additionally, it was demonstrated that the concentration of cyclic guanosine 3',5'-monophosphate (cGMP) is increased by NPPA and NPPC in oocytes and cumulus cells after 3h of in vitro maturation. However, in both groups, the concentration of cyclic adenosine 3',5'-monophosphate (cAMP) in the oocyte did not increase between 3 and 6h of culture, even when forskolin was used. In summary, we observed the presence of mRNA for NPs and their receptors in the bovine cumulus-oocyte complex and demonstrated that, in vitro, NPPA, NPPB and NPPC stimulate oocyte meiotic resumption in a monovular species.

  3. Entrainment of intestinal slow waves with electrical stimulation using intraluminal electrodes.

    PubMed

    Lin, X; Hayes, J; Peters, L J; Chen, J D

    2000-05-01

    The aim of this study was to investigate whether the intestinal stimulation would be feasible using a less invasive method: intraluminal electrodes. The study was performed in nine healthy hound dogs (15-26 kg). Four pairs of electrodes were implanted on the serosa of the jejunum at an interval of 5 cm with the most proximal pair 35 cm beyond the pylorus. An intestinal fistula was made 20 cm beyond the pylorus. Simultaneous recordings of intestinal myoelectrical activity were made for 2 h in the fasting state from both intraluminal and serosal electrodes. Various pacing parameters were tested. The frequency of the intestinal slow wave recorded from the intraluminal electrodes was identical to that from the serosal electrodes (18.78+/-0.3 cpm vs 18.75+/-0.3 cpm, r=0.99, p <0.001), and so was the percentage of normal 17-22 cycles/ min waves (95.83+/-3.9% vs 98.16+/-1.33%, r=0.96, p<0.01). A complete entrainment of the intestinal slow wave was achieved in every dog with electrical stimulation using intraluminal ring electrodes. The effective pacing parameters were pulse width of 70 ms, amplitude of 4 mA and frequency of 1.1 IF (intrinsic frequency). The time required for the entrainment of the intestinal slow wave with intraluminal pacing was 25.0+/-2.1 s. The maximum driven frequency was found to be 1.43+/-0.01 IF. The results reveal that intraluminal pacing is an effective and efficient method for the entrainment of intestinal slow waves. It may become a potential approach for the treatment of intestinal motor disorders associated with myoelectrical abnormalities.

  4. [Responses of peptide hydrolases of the small and large intestines in rats on the administration of antibiotics].

    PubMed

    Borshchëv, Iu Iu; Gromova, L V; Ermolenko, E I; Grefner, N M; Borshchëva, I Iu; Gruzdkov, A A

    2012-06-01

    Effects of antibiotics on the structure and functional state of the intestine are not clear. We investigated some structural parameters of the small and large intestine, and activities of two intestinal peptide hydrolases in rats after administration of ampicillin and metronidazole during 3 and 5 days. After 3 days of antibiotic administration a decrease in the weight of mucosa in the small intestine, accompanied with a reduction in the villous height and width in this part of the intestine, and in the weight ofmucosa in the colon occured. At the same time the number of goblet cells in the small intestinal epithelium was increased. Specific activities of aminopeptidase M, and glycyl-L-leucine dipeptidase (micromol/min per g) in the mucosa of the small intestine were increased, and the total activities (micromol/min calculated per a part of the intestine) of the same enzymes did not change. The administration of antibiotics for 5 days resulted in increase of specific activity ofaminopeptidase M in the mucosa of the proximal part of the small intestine. In the chyme of the small intestine and colon, activities of the same enzymes (micromol/min calculated per a part of the intestine) were increased on the third and fifth days of the antibiotic administration. Thus, the application ofampicillin and metronidazole within 3-5 days causes a disturbance of the structural and functional parameters in the small and large intestines, which is most pronounced on the third day of the drug administration.

  5. Effects of composite antimicrobial peptides in weanling piglets challenged with deoxynivalenol: II. Intestinal morphology and function.

    PubMed

    Xiao, H; Tan, B E; Wu, M M; Yin, Y L; Li, T J; Yuan, D X; Li, L

    2013-10-01

    Deoxynivalenol (DON) affects animal and human health and targets the gastrointestinal tract. The objective of this study was to evaluate the ability of composite antimicrobial peptides (CAP) to repair intestinal injury in piglets challenged with DON. A total of 28 piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% composite antimicrobial peptide (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 mg/kg DON + 0.4% CAP (DON + CAP). After an adaptation period of 7 d, blood samples were collected on d 15 and 30 after the initiation of treatment for determinations of the concentrations of D-lactate and diamine oxidase. At the end of the study, all piglets were slaughtered to obtain small intestines for the determination of intestinal morphology, epithelial cell proliferation, and protein expression in the mammalian target of rapamycin (mTOR) signaling pathway. The results showed that DON increased serum concentrations of D-lactate and diamine oxidase, and these values in the CAP and DON + CAP treatments were less than those in the NC and DON treatments, respectively (P < 0.05). The villous height/crypt depth in the jejunum and ileum and the goblet cell number in the ileum in the CAP and DON + CAP treatments were greater than those in the NC and DON treatments (P < 0.05). The proliferating cell nuclear antigen (PCNA) labeling indexes for the jejunum and ileum in the DON + CAP treatment were greater than those in the DON treatment (P < 0.05). The DON decreased (P < 0.05) the relative protein expression of phosphorylated Akt (Protein Kinase B) and mTOR in the jejunal and ileal mucosa and of phosphorylated 4E-binding protein 1 (p-4EBP1) in the jejunal mucosa, whereas CAP increased (P < 0.05) the protein expression of p-4EBP1 in the jejunum. These findings showed that DON could enhance intestinal permeability, damage villi

  6. Salinity-Dependent Shift in the Localization of Three Peptide Transporters along the Intestine of the Mozambique Tilapia (Oreochromis mossambicus)

    PubMed Central

    Con, Pazit; Nitzan, Tali; Cnaani, Avner

    2017-01-01

    The peptide transporter (PepT) systems are well-known for their importance to protein absorption in all vertebrate species. These symporters use H+ gradient at the apical membrane of the intestinal epithelial cells to mediate the absorption of small peptides. In fish, the intestine is a multifunctional organ, involved in osmoregulation, acid-base regulation, and nutrient absorption. Therefore, we expected environmental stimuli to affect peptide absorption. We examined the effect of three environmental factors; salinity, pH and feeding, on the expression, activity and localization of three PepT transporters (PepT1a, PepT1b, PepT2) along the intestine of the Mozambique tilapia (Oreochromis mossambicus). Quantitative real time PCR (qPCR) analysis demonstrated that the two PepT1 variants are typical to the proximal intestinal section while PepT2 is typical to the distal intestinal sections. Immunofluorescence analysis with custom-made antibodies supported the qPCR results, localized both transporters on the apical membrane of enterocytes and provided the first evidence for the participation of PepT2 in nutrient absorption. This first description of segment-specific expression and localization points to a complementary role of the different peptide transporters, corresponding to the changes in nutrient availability along the intestine. Both gene expression and absorption activity assays showed that an increase in water salinity shifted the localization of the PepT genes transcription and activity down along the intestinal tract. Additionally, an unexpected pH effect was found on the absorption of small peptides, with increased activity at higher pH levels. This work emphasizes the relationships between different functions of the fish intestine and how they are affected by environmental conditions. PMID:28167916

  7. Deficient Vasoactive Intestinal Peptide Innervation in the Sweat Glands of Cystic Fibrosis Patients

    NASA Astrophysics Data System (ADS)

    Heinz-Erian, Peter; Dey, Richard D.; Flux, Marinus; Said, Sami I.

    1985-09-01

    The innervation of acini and ducts of eccrine sweat glands by immunoreactive, vasoactive intestinal peptide--containing nerve fibers was sharply reduced in seven patients with cystic fibrosis compared to eight normal subjects. The decrease in innervation by this neuropeptide, which has been shown to promote blood flow and the movement of water and chloride across epithelial surfaces in other systems, may be a basic mechanism for the decreased water content and relative impermeability of the epithelium to chloride and other ions that characterize cystic fibrosis.

  8. [Role of antimicrobial peptides (AMP) and pattern recognition receptors (PRR) in the intestinal mucosa homeostasis].

    PubMed

    Lapis, Károly

    2009-11-22

    Homeostasis and integrity of bowel mucosa is assured by well controlled mechanical, biochemical and immunological mechanisms. First line of defense is presented by the antimicrobial peptides (AMP), which form a continuous layer on the bowel surface, produced by intestinal specific (Paneth) and non-specific epithelial cells. AMPs have a significant antimicrobial, antifungal and antiviral, as well as immunomodulatory effects. Next line of defense is the pattern recognition receptors (PRR), which allows identifying conservative molecular patterns of different pathogens, and starts antimicrobial and inflammatory mechanisms through gene-expression induction. We review the most recent knowledge and studies concerning these mechanisms.

  9. Citrullinemia stimulation test in the evaluation of the intestinal function.

    PubMed

    Pinto Costa, Beatriz; Serôdio, Marco; Simões, Marta; Veríssimo, Carla; Castro Sousa, F; Grazina, Manuela

    2013-01-01

    Introducción: Citrulinemia sí ha reportado como un parámetro cuantitativo de la masa y la función del enterocito. Objetivo: El objetivo de esta investigación es analizar el valor de las citrulinemias en ayuno y estimulada en la evaluación de la función intestinal. Métodos: Un estudio de casos y controles se llevó a cabo, incluyendo 11 enfermos con síndrome del intestino corto, 13 pacientes sometidos a cirugía bariátrica de malabsorción y 11 controles sanos. Los niveles plasmáticos de aminoácidos se determinaron, antes y después de la prueba de estimulación oral con L-glutamina, por cromatografía de intercambio iónico. Resultados: Citrulinemia fue menor en los pacientes de intestino corto (28,6 ± 11,3 versus 35,5 ± 11 en los obesos operados versus 32,2 ± 6,6 μmol/L en los controles; n.s.) e inferior a 25,5 μmol/L en el 54,5% de ellos (versus 16,7%; p = 0,041, exactitud = 74%, odds ratio = 3, IC95% 1,2 a 7,6). ?Citrullinemia80 (variación relativa de la citrulinemia a los 80 minutos de la prueba) fue menor en enfermos de intestino corto; su precisión diagnóstica fue similar a la citrulinemia en ayuno y también no significativa. ?Citrullinemia80 reveló una elevada capacidad predictiva de intestino corto inferior o igual a 50 cm (abR.O.C. = 82,3%; IC95% 61,7-102,8; p = 0,038). Conclusiones: En el contexto de lo síndrome de intestino corto, la prueba de estimulación de la citrulinemia con L-glutamina oral es factible y puede mejorar la capacidad predictiva de gravedad. Se requieren nuevas investigaciones para determinar su importancia clínica y aplicabilidad.

  10. Role of phosphatidylinositol-3 kinase-gamma in the actions of glucagon-like peptide-2 on the murine small intestine.

    PubMed

    Anini, Younes; Izzo, Angelo; Oudit, Gavin Y; Backx, Peter H; Brubaker, Patricia L

    2007-06-01

    Glucagon-like peptide-2 (GLP-2) enhances intestinal growth and function through a cAMP-linked G protein-coupled receptor (GPCR) expressed in the mucosal layer and enteric nervous system. Because the type 1B gamma-isoform of phosphatidylinositol 3-kinase (PI3-K) is activated by GPCRs, we determined whether this enzyme plays a role in the intestinal actions of GLP-2 by using PI3-Kgamma knockout (KO) mice. Wild-type (WT), heterozygous, and KO mice were treated with vehicle or 1 microg Gly2-GLP-2 (a long-acting analog) twice daily for 10 days and analyzed for changes in intestinal growth, motility, and cAMP production. Basal small intestinal wet weight was increased in KO mice in association with enhanced crypt-villus height and crypt cell proliferation (P < 0.05-0.01). However, the GLP-2-induced changes in these parameters were not different between KO and WT animals. GLP-2 treatment also enhanced the number of mucous cells in the intestinal epithelium, but this effect was lost in the PI3-Kgamma KO mice. Both basal and GLP-2-induced suppression of intestinal transit were normal in KO mice. In contrast, the ability of GLP-2 to stimulate cAMP levels in isolated muscle strips was abrogated by loss of PI3-Kgamma, despite the expression of GLP-2 receptor mRNA transcripts in this tissue. Together, the results of this study demonstrate a role for PI3-Kgamma in basal but not GLP-2-induced small intestinal mucosal growth. However, PI3-Kgamma is important for the enhancement of mucous cell number by GLP-2 and in the ability of the GLP-2 receptor to couple to cAMP in the enteric nervous system.

  11. Novel GM1 ganglioside-like peptide mimics prevent the association of cholera toxin to human intestinal epithelial cells in vitro

    PubMed Central

    Yu, Robert K; Usuki, Seigo; Itokazu, Yutaka; Wu, Han-Chung

    2016-01-01

    Cholera is an acute diarrheal disease caused by infection in the gastrointestinal tract by the gram-negative bacterium, Vibrio cholerae, and is a serious public health threat worldwide. There has not been any effective treatment for this infectious disease. Cholera toxin (CT), which is secreted by V. cholerae, can enter host cells by binding to GM1, a monosialoganglioside widely distributed on the plasma membrane surface of various animal epithelial cells. The present study was undertaken to generate peptides that are conformationally similar to the carbohydrate epitope of GM1 for use in the treatment of cholera and related bacterial infection. For this purpose, we used cholera toxin B (CTB) subunit to select CTB-binding peptides that structurally mimic GM1 from a dodecamer phage-display library. Six GM1-replica peptides were selected by biopanning based on CTB recognition. Five of the six peptides showed inhibitory activity for GM1 binding to CTB. To test the potential of employing the peptide mimics for intervening with the bacterial infection, those peptides were examined for their binding capacity, functional inhibitory activity and in vitro effects using a human intestinal epithelial cell line, Caco-2 cells. One of the peptides, P3 (IPQVWRDWFKLP), was most effective in inhibiting cellular uptake of CTB and suppressing CT-stimulated cyclic adenosine monophosphate production in the cells. Our results thus provide convincing evidence that GM1-replica peptides could serve as novel agents to block CTB binding on epithelial cells and prevent the ensuing physiological effects of CT. PMID:26405107

  12. Bifidobacteria inhibit the inflammatory response induced by gliadins in intestinal epithelial cells via modifications of toxic peptide generation during digestion.

    PubMed

    Laparra, J M; Sanz, Y

    2010-03-01

    Celiac disease (CD) is a chronic enteropathy triggered by intake of gliadin, the toxic component of gluten. This study aims at evaluating the capacity of different Bifidobacterium strains to counteract the inflammatory effects of gliadin-derived peptides in intestinal epithelial (Caco-2) cells. A commercial extract of several gliadin (Gld) types (alpha, beta, gamma, [symbol: see text] ) was subjected to in vitro gastrointestinal digestion (pepsin at pH 3, pancreatin-bile at pH 6), inoculated or not with cell suspensions (10(8) colony forming units/ml) of either B. animalis IATA-A2, B. longum IATA-ES1, or B. bifidum IATA-ES2, in a bicameral system. The generated gliadin-derived peptides were identified by reverse phase-HPLC-ESI-MS/MS. Caco-2 cell cultures were exposed to the different gliadin peptide digestions (0.25 mg protein/ml), and the mRNA expression of nuclear factor kappa-B (NF-kappaB), tumor necrosis factor alpha (TNF-alpha), and chemokine CXCR3 receptor were analyzed by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) in stimulated cells. The production of the pro-inflammatory markers NF-kappaB p50, TNF-alpha, and IL-1beta (interleukine 1beta) by Caco-2 cells was also determined by ELISA. The peptides from gliadin digestions inoculated with bifidobacteria did not exhibit the toxic amino acid sequences identified in those noninoculated (alpha/beta-Gld [158-164] and alpha/beta-Gld [122-141]). The RT-PCR analysis evidenced a down-regulation in mRNA expression of pro-inflammatory biomarkers. Consistent with these results the production of NF-kappaB, TNF-alpha, and IL-1beta was reduced (18.2-22.4%, 28.0-64.8%, and abolished, respectively) in cell cultures exposed to gliadin digestions inoculated with bifidobacteria. Therefore, bifidobacteria change the gliadin-derived peptide pattern and, thereby, attenuate their pro-inflammatory effects on Caco-2 cells.

  13. Cupric-amyloid beta peptide complex stimulates oxidation of ascorbate and generation of hydroxyl radical.

    PubMed

    Dikalov, Sergey I; Vitek, Michael P; Mason, Ronald P

    2004-02-01

    A growing body of evidence supports an important role for oxidative stress in the pathogenesis of Alzheimer's disease. Recently, a number of papers have shown a synergistic neurotoxicity of amyloid beta peptide and cupric ions. We hypothesized that complexes of cupric ions with neurotoxic amyloid beta peptides (Abeta) can stimulate copper-mediated free radical formation. We found that neurotoxic Abeta (1-42), Abeta (1-40), and Abeta (25-35) stimulated copper-mediated oxidation of ascorbate, whereas nontoxic Abeta (40-1) did not. Formation of ascorbate free radical was significantly increased by Abeta (1-42) in the presence of ceruloplasmin. Once cupric ion is reduced to cuprous ion, it can be oxidized by oxygen to generate superoxide radical or it can react with hydrogen peroxide to form hydroxyl radical. Hydrogen peroxide greatly increased the oxidation of cyclic hydroxylamines and ascorbate by cupric-amyloid beta peptide complexes, implying redox cycling of copper ions. Using the spin-trapping technique, we have shown that toxic amyloid beta peptides led to a 4-fold increase in copper-mediated hydroxyl radical formation. We conclude that toxic Abeta peptides do indeed stimulate copper-mediated oxidation of ascorbate and generation of hydroxyl radicals. Therefore, cupric-amyloid beta peptide-stimulated free radical generation may be involved in the pathogenesis of Alzheimer's disease.

  14. Nesfatin-1 stimulates cholecystokinin and suppresses peptide YY expression and secretion in mice.

    PubMed

    Ramesh, Naresh; Mortazavi, Sima; Unniappan, Suraj

    2016-03-25

    Nesfatin-1 is an 82 amino acid secreted peptide encoded in the precursor, nucleobindin-2 (NUCB2). It is an insulinotropic anorexigen abundantly expressed in the stomach and hypothalamus. Post-prandial insulin secretion is predominantly regulated by incretins glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Nesfatin-1 was previously reported to modulate GLP-1 and GIP secretion in vitro in an enteroendocrine (STC-1) cell line. Intestine is a source of additional hormones including cholecystokinin (CCK) and peptide YY (PYY) that regulate metabolism. We hypothesized that nesfatin-1 modulates CCK and PYY secretion. Immunofluorescence histochemistry showed NUCB2/nesfatin-1 co-localizing CCK and PYY in the intestinal mucosa of mice. Static incubation of STC-1 cells with nesfatin-1 upregulated both CCK mRNA expression (1 and 10 nM) and secretion (0.1, 1 and 10 nM) at 1 h post-incubation. In contrast, nesfatin-1 treatment for 1 h downregulated PYY mRNA expression (all doses tested) and secretion (0.01 and 0.1 nM) in STC-1 cells. Continuous infusion of nesfatin-1 using osmotic mini-pumps for 12 h upregulated CCK mRNA expression in large intestine, and downregulated PYY mRNA expression in both large and small intestines of male C57BL/6J mice. In these tissues, Western blot analysis found a corresponding increase in CCK and a decrease in PYY content. Collectively, we provide new information on the cell specific localization of NUCB2/nesfatin-1 in the intestinal mucosa, and a novel function for nesfatin-1 in modulating intestinal CCK and PYY expression and secretion in mice.

  15. SPARC is a source of copper-binding peptides that stimulate angiogenesis

    PubMed Central

    1994-01-01

    SPARC is a transiently expressed extracellular matrix-binding protein that alters cell shape and regulates endothelial cell proliferation in vitro. In this study, we show that SPARC mRNA and protein are synthesized by endothelial cells during angiogenesis in vivo. SPARC and peptides derived from a cationic region of the protein (amino acids 113- 130) stimulated the formation of endothelial cords in vitro; moreover, these peptides stimulated angiogenesis in vivo. Mapping of the active domain demonstrated that the sequence KGHK was responsible for most of the angiogenic activity; substitution of the His residue decreased the effect. We found that proteolysis of SPARC provided a source of KGHK, GHK, and longer peptides that contained these sequences. Although the Cu(2+)-GHK complex had been identified as a mitogen/morphogen in normal human plasma, we found KGHK and longer peptides to be potent stimulators of angiogenesis. SPARC113-130 and KGHK were shown to bind Cu2+ with high affinity; however, previous incubation with Cu2+ was not required for the stimulatory activity. Since a peptide from a second cationic region of SPARC (SPARC54-73) also bound Cu2+ but had no effect on angiogenesis, the angiogenic activity appeared to be sequence specific and independent of bound Cu2+. Thus, specific degradation of SPARC, a matrix-associated protein expressed by endothelial cells during vascular remodeling, releases a bioactive peptide or peptides, containing the sequence (K)GHK, that could regulate angiogenesis in vivo. PMID:7514608

  16. Intestinal Lin- c-Kit+ NKp46- CD4- population strongly produces IL-22 upon IL-1β stimulation.

    PubMed

    Lee, Youngae; Kumagai, Yutaro; Jang, Min Seong; Kim, Jung-Hwan; Yang, Bo-Gie; Lee, Eun-Jung; Kim, You-Me; Akira, Shizuo; Jang, Myoung Ho

    2013-05-15

    Small intestinal innate lymphoid cells (ILCs) regulate intestinal epithelial cell homeostasis and help to prevent pathogenic bacterial infections by producing IL-22. In a global gene-expression analysis comparing small intestinal ILCs (Lin(-)c-Kit(+)Sca-1(-) cells) with non-ILCs (Lin(-)c-Kit(-)Sca-1(-) cells), we found that Lin(-)c-Kit(+)Sca-1(-) cells highly expressed the mRNAs for Il22, antimicrobial peptides, Csf2rb2 (Il3r), mast cell proteases, and Rorc. We then subdivided the Lin(-)c-Kit(+)Sca-1(-) cells into three groups--Lin(-)c-Kit(+)NKp46(-)CD4(-), Lin(-)c-Kit(+)NKp46(-)CD4(+) (CD4(+) LTi-like cells), and Lin(-)c-Kit(+)NKp46(+) (NKp46(+) ILC22 cells)--and showed that the Lin(-)c-Kit(+)NKp46(-)CD4(-) cells produced the highest level of IL-22 protein after IL-1β, IL-23, or IL-1β and IL-23 stimulation. In addition, we showed that the majority of the Lin(-)c-Kit(+)NKp46(-)CD4(-) population was IL-7Rα(+)CD34(-)β7(int) cells, and IL-7Rα(-) cells could be divided into three subsets (CD34(+)β7(int), CD34(-)β7(int), and CD34(int)β7(hi) cells). The IL-7Rα(+)CD34(-)β7(int) cells strongly expressed the transcripts for Il17f and Il22 after costimulation with IL-1β and IL-23. The IL-7Rα(-)CD34(+)β7(int) and IL-7Rα(-)CD34(int)β7(hi) cells predominantly expressed the transcripts for mast cell proteases and differentiated almost entirely into mast cells after 1 wk in culture medium supplemented with a cytokine mixture, whereas the IL-7Rα(-)CD34(-)β7(int) cells highly expressed α-defensins and showed no differentiation. Taken together, these findings indicate that the IL-7Rα(-)CD34(+)β7(int) and IL-7Rα(-)CD34(int)β7(hi) populations are mast cell progenitors, and the IL-7Rα(+)CD34(-)β7(int) (CD4(-) LTi-like cells) and IL-7Rα(-)CD34(-)β7(int) populations within Lin(-)c-Kit(+)NKp46(-)CD4(-) cells may control intestinal homeostasis and provide intestinal protection by producing high levels of IL-22 and α-defensins, respectively.

  17. Stimulatory effect of the intestinal peptide PHI on glycogenolysis and gluconeogenesis in isolated rat hepatocytes.

    PubMed Central

    Felíu, J E; Marco, J

    1983-01-01

    The newly isolated peptide PHI provoked a dose-dependent stimulation of glycogenolysis and gluconeogenesis in isolated rat hepatocytes; at 1 microM-PHI, both processes were increased 1.6-fold as compared with basal values. These PHI-mediated effects were accompanied by the activation of glycogen phosphorylase and the inactivation of pyruvate kinase. PHI (1 microM) also caused a 2-fold increase in hepatocyte cyclic AMP. PMID:6312969

  18. Amphipathic polyproline peptides stimulate cholesterol efflux by the ABCA1 transporter.

    PubMed

    Sviridov, D O; Drake, S K; Freeman, L A; Remaley, A T

    2016-03-18

    ApoA-I mimetics are short synthetic peptides that contain an amphipathic α-helix and stimulate cholesterol efflux by the ABCA1 transporter in a detergent-like extraction mechanism. We investigated the use of amphipathic peptides with a polypro helix for stimulating cholesterol efflux by ABCA1. Polypro peptides were synthesized with modified prolines, containing either a hydrophobic phenyl group (Prop) or a polar N-acetylgalactosamine (Prog) attached to the pyrrolidine ring and were designated as either PP-2, 3, 4, or 5, depending on the number of 3 amino acid repeat units (Prop-Prog-Prop). Based on molecular modeling, these peptides were predicted to be relatively rigid and to bind to a phospholipid bilayer. By CD spectroscopy, PP peptides formed a Type-II polypro helix in an aqueous solution. PP-2 was inactive in promoting cholesterol efflux, but peptides with more than 2 repeat units were active. PP-4 showed a similar Vmax as a much longer amphipathic α-helical peptide, containing 37 amino acids, but had a Km that was approximately 20-fold lower. PP peptides were specific in that they did not stimulate cholesterol efflux from cells not expressing ABCA1 and were also non-cytotoxic. Addition of PP-3, 4 and 5 to serum promoted the formation of smaller size HDL species (7 nM) and increased its capacity for ABCA1-dependent cholesterol efflux by approximately 20-35% (p < 0.05). Because of their relatively small size and increased potency, amphipathic peptides with a polypro helix may represent an alternative structural motif for the development of apoA-I mimetic peptides.

  19. Effects of pig antibacterial peptides on growth performance and intestine mucosal immune of broiler chickens.

    PubMed

    Bao, H; She, R; Liu, T; Zhang, Y; Peng, K S; Luo, D; Yue, Z; Ding, Y; Hu, Y; Liu, W; Zhai, L

    2009-02-01

    Currently, substitutions for antibiotic growth promoters in animals are attracting interest. This study investigated the effects of pig antibacterial peptides (PABP) on growth performance and small intestine mucosal immune responses in broilers. Three hundred 1-d-old Arbor Acre male broiler chickens were randomly allocated to 5 groups with 60 birds per group. The groups were control group; PABP administered in drinking water at 20 and 30 mg/L of water; or PABP supplemented in feed at 150 and 200 mg/kg of diet. The birds were fed a corn-soybean based diet for 6 wk. Chickens were weighed weekly and killed after 42 d of feeding, and growth performance was measured. Samples of the duodenum and jejunum were collected. The villus height, mucosa thickness, alkaline phosphatase activity, and numbers of secreting IgA and goblet cells were evaluated. The PABP-treated groups had greater BW and average daily gain, greater height of villus and thickness of gut mucosa, greater activity of alkaline phosphatase, higher ratio of secreting IgA, and a greater number of goblet cells compared with the control group (P<0.05). In conclusion, PABP can improve the growth performance, increase the intestinal ability to absorb nutrients, and improve the mucosal immunity of the intestine.

  20. Identification of peptide-specific TCR genes by in vitro peptide stimulation and CDR3 length polymorphism analysis.

    PubMed

    Shao, Hongwei; Lin, Yanmei; Wang, Teng; Ou, Yusheng; Shen, Han; Tao, Changli; Wu, Fenglin; Zhang, Wenfeng; Bo, Huaben; Wang, Hui; Huang, Shulin

    2015-07-10

    Identification of TCR genes specific for tumor-associated antigens (TAAs) is necessary for TCR gene modification of T cells, which is applied in anti-tumor adoptive T cell therapy (ACT). The usual identification methods are based on isolating single peptide-responding T cells and cloning the TCR gene by in vitro expansion or by single-cell RT-PCR. However, the long and exacting in vitro culture period and demanding operational requirements restrict the application of these methods. Immunoscope is an effective tool that profiles a repertoire of TCRs and identifies significantly expanded clones through CDR3 length analysis. In this study, a survivin-derived mutant peptide optimized for HLA-A2 binding was selected to load DCs and activate T cells. The monoclonal expansion of TCRA and TCRB genes was separately identified by Immunoscope analysis and following sequence identification, the properly paired TCR genes were transferred into T cells. Peptide recognition and cytotoxicity assays indicated that TCR-modified PBMCs could respond to both the mutant and wild type peptides and lyse target cells. These results show that combining Immunoscope with in vitro peptide stimulation provides an alternative and superior method for identifying specific TCR genes, which represents a significant advance for the application of TCR gene-modified T cells.

  1. Mucosally transplanted mesenchymal stem cells stimulate intestinal healing by promoting angiogenesis

    PubMed Central

    Manieri, Nicholas A.; Mack, Madison R.; Himmelrich, Molly D.; Worthley, Daniel L.; Hanson, Elaine M.; Eckmann, Lars; Wang, Timothy C.; Stappenbeck, Thaddeus S.

    2015-01-01

    Mesenchymal stem cell (MSC) therapy is an emerging field of regenerative medicine; however, it is often unclear how these cells mediate repair. Here, we investigated the use of MSCs in the treatment of intestinal disease and modeled abnormal repair by creating focal wounds in the colonic mucosa of prostaglandin-deficient mice. These wounds developed into ulcers that infiltrated the outer intestinal wall. We determined that penetrating ulcer formation in this model resulted from increased hypoxia and smooth muscle wall necrosis. Prostaglandin I2 (PGI2) stimulated VEGF-dependent angiogenesis to prevent penetrating ulcers. Treatment of mucosally injured WT mice with a VEGFR inhibitor resulted in the development of penetrating ulcers, further demonstrating that VEGF is critical for mucosal repair. We next used this model to address the role of transplanted colonic MSCs (cMSCs) in intestinal repair. Compared with intravenously injected cMSCs, mucosally injected cMSCs more effectively prevented the development of penetrating ulcers, as they were more efficiently recruited to colonic wounds. Importantly, mucosally injected cMSCs stimulated angiogenesis in a VEGF-dependent manner. Together, our results reveal that penetrating ulcer formation results from a reduction of local angiogenesis and targeted injection of MSCs can optimize transplantation therapy. Moreover, local MSC injection has potential for treating diseases with features of abnormal angiogenesis and repair. PMID:26280574

  2. Molecular forms of peptide histidine isoleucine-like immunoreactivity in the gastrointestinal tract. Nonequimolar levels of peptide histidine isoleucine and vasoactive intestinal peptide in the stomach explained by the presence of a big peptide histidine isoleucine-like molecule.

    PubMed

    Yiangou, Y; Christofides, N D; Blank, M A; Yanaihara, N; Tatemoto, K; Bishop, A E; Polak, J M; Bloom, S R

    1985-09-01

    Regional specific antibodies and chromatography were used to analyze the distributions and molecular forms of peptide histidine isoleucine (PHI) and vasoactive intestinal peptide (VIP) in the porcine intestine. Both peptides were present along the entire length of the intestine, the highest concentrations occurring in the colon. Concentrations of PHI immunoreactivity, measured with three different antisera, and VIP immunoreactivity were approximately equal in all parts of the gastrointestinal tract except in the stomach. In the stomach, the concentration of PHI immunoreactivity, measured with the N-terminally directed antibody R8403, although equal to the corresponding VIP concentration, was two to four times higher than the PHI immunoreactivity detected with the two C-terminally directed PHI antisera T33 and T41. Chromatographic analysis on Sephadex G-50 superfine of gastric extracts revealed only one VIP immunoreactive peak that eluted in the same position as the porcine VIP standard, at Kav 0.53. A PHI immunoreactive peak was also detected with the C-terminally directed PHI antisera in the same position as porcine PHI standard. However, with the N-terminally directed PHI antiserum R8403, an additional PHI immunoreactive peak was detected in gastric extracts constituting the predominant form present, and this peak eluted earlier at Kav 0.37. The PHI immunoreactive material that eluted earlier was present in the rest of the intestine in only small amounts. As VIP and PHI are believed to be derived from a common precursor, it is suggested that in the stomach the posttranslational enzymic processing of the precursor is different from that in the other parts of the intestine.

  3. Transitions in oral and intestinal microflora composition and innate immune receptor-dependent stimulation during mouse development.

    PubMed

    Hasegawa, Mizuho; Osaka, Toshifumi; Tawaratsumida, Kazuki; Yamazaki, Takashi; Tada, Hiroyuki; Chen, Grace Y; Tsuneda, Satoshi; Núñez, Gabriel; Inohara, Naohiro

    2010-02-01

    Commensal bacteria possess immunostimulatory activities that can modulate host responses to affect development and homeostasis in the intestine. However, how different populations of resident bacteria stimulate the immune system remains largely unknown. We characterized here the ability of intestinal and oral microflora to stimulate individual pattern recognition receptors (PRRs) in bone marrow-derived macrophages and mesothelial cells. The intestinal but not oral microflora elicited age- and cell type-specific immunostimulation. The immunostimulatory activity of the intestinal microflora varied among individual mice but was largely mediated via Toll-like receptor 4 (TLR4) during breast-feeding, whereas it became TLR4 independent after weaning. This transition was associated with a change from a microflora rich in TLR4-stimulatory proteobacteria to one dominated by Bacteroidales and/or Clostridiales that poorly stimulate TLR4. The major stimulatory activity of the intestinal microflora was still intact in NOD1-, NOD2-, TLR2-, TLR4-, TLR5-, TLR9-, TLR11-, ASC-, or RICK-deficient cells but still relied on the adaptor MyD88. These studies demonstrate a transition in the intestinal microflora accompanied by a dynamic change of its ability to stimulate different PRRs which control intestinal homeostasis.

  4. Intestine.

    PubMed

    Smith, J M; Skeans, M A; Horslen, S P; Edwards, E B; Harper, A M; Snyder, J J; Israni, A K; Kasiske, B L

    2016-01-01

    Intestine and intestine-liver transplant plays an important role in the treatment of intestinal failure, despite decreased morbidity associated with parenteral nutrition. In 2014, 210 new patients were added to the intestine transplant waiting list. Among prevalent patients on the list at the end of 2014, 65% were waiting for an intestine transplant and 35% were waiting for an intestine-liver transplant. The pretransplant mortality rate decreased dramatically over time for all age groups. Pretransplant mortality was highest for adult candidates, at 22.1 per 100 waitlist years compared with less than 3 per 100 waitlist years for pediatric candidates, and notably higher for candidates for intestine-liver transplant than for candidates for intestine transplant without a liver. Numbers of intestine transplants without a liver increased from a low of 51 in 2013 to 67 in 2014. Intestine-liver transplants increased from a low of 44 in 2012 to 72 in 2014. Short-gut syndrome (congenital and other) was the main cause of disease leading to both intestine and intestine-liver transplant. Graft survival improved over the past decade. Patient survival was lowest for adult intestine-liver recipients and highest for pediatric intestine recipients.

  5. Peptides having reduced toxicity that stimulate cholesterol efflux

    DOEpatents

    Bielicki, John K.; Johansson, Jan; Danho, Waleed

    2016-08-16

    The present invention provides a family of non-naturally occurring polypeptides having cholesterol efflux activity that parallels that of full-length apolipoproteins (e.g., Apo AI and Apo E), and having high selectivity for ABCA1 that parallels that of full-length apolipoproteins. Further, the peptides of the invention have little or no toxicity when administered at therapeutic and higher doses. The invention also provides compositions comprising such polypeptides, methods of identifying, screening and synthesizing such polypeptides, and methods of treating, preventing or diagnosing diseases and disorders associated with dyslipidemia, hypercholesterolemia and inflammation.

  6. Expression of an antimicrobial peptide, digestive enzymes and nutrient transporters in the intestine of E. praecox-infected chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coccidiosis is a major intestinal disease of poultry, caused by several species of the protozoan Eimeria. The objective of this study was to examine changes in expression of digestive enzymes, nutrient transporters and an antimicrobial peptide following an Eimeria praecox challenge of chickens at d...

  7. Bile acids induce glucagon-like peptide 2 secretion with limited effects on intestinal adaptation in early weaned pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early weaning is a stressful event characterized by a transient period of intestinal atrophy that may be mediated by reduced secretion of glucagon-like peptide (GLP) 2. We tested whether enterally fed bile acids or plant sterols could increase nutrient-dependent GLP-2 secretion and improve intestina...

  8. Glucagon-like peptide-2 (GLP-2) increases small intestinal blood flow and mucosal growth in ruminating calves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glucagon-like peptide-2 (GLP-2), increases small intestinal mass and blood flow in non-ruminants, but its effect in ruminants is unknown. Eight Holstein calves with an ultrasonic flow probe around the superior mesenteric artery (SMA), and catheters in the carotid artery and mesenteric vein, were pa...

  9. Melanocyte stimulating hormone peptides inhibit TNF-alpha signaling in human dermal fibroblast cells.

    PubMed

    Hill, R P; MacNeil, S; Haycock, J W

    2006-02-01

    Alpha-melanocyte stimulating hormone (alpha-MSH) has been identified as a potent anti-inflammatory in various tissues including the skin. It has previously been shown in skin cell keratinocytes and melanocytes/melanoma cells that MSH peptides inhibit TNF-alpha stimulated NF-kappaB activity and intercellular adhesion molecule-1 (ICAM-1) upregulation. However, the precise anti-inflammatory role of MSH peptides in dermal fibroblasts is unclear. Some studies report on pro-inflammatory responses, while others on anti-inflammatory responses. The present study confirms MC1R expression in cultured human dermal fibroblasts and reports that the MSH peptides alpha-MSH and KP(-D-)V inhibit TNF-alpha stimulated NF-kappaB activity and ICAM-1 upregulation, consistent with an anti-inflammatory role. However, involvement of IkappaB-alpha regulation by either peptide was not confirmed, supporting a mechanism independent of the NF-kappaB inhibitor. In conclusion, alpha-MSH and KP(-D-)V peptides have an anti-inflammatory action on dermal fibroblast signaling by inhibiting the pro-inflammatory activity of TNF-alpha in vitro.

  10. The effect of atrial natriuretic peptide infusion on intestinal injury in septic shock

    PubMed Central

    Elbaradey, Ghada F.; Elshmaa, Nagat Sayed; Hodeib, Hossam

    2016-01-01

    Background and Aims: The aim of this study is to assess the effect of atrial natriuretic peptide (ANP) on intestinal ischemia-reperfusion injury in septic shock. Material and Methods: A prospective randomized controlled, observer-blinded study was carried out in surgical Intensive Care Unit (ICU), University Hospital. Forty adult patients in septic shock were randomly divided into two groups, control group (Group C) received normal saline and ANP group (Group A) patients received ANP in the form of 1.5 mg vial added to 250 ml solvent in plastic bag (1 ml = 6 micg) given at 2 mcg/kg intravenous bolus over 1 min followed by 0.01 mcg/kg/min for 24 h. The primary outcome measurements were blood marker of intestinal hypoperfusion in form of intestinal fatty acid binding protein (I-FABP), malondialdehyde (MDA), myloperoxidase enzyme activity (MPO), protein carbonyl (PC), and glutathione peroxidase activity (GPA) measured before start of ANP infusion, 6 h, 12 h, and 24 h after start of infusion. The secondary outcome measurements were the duration of noradrenaline infusion, duration of ICU stay, hospital mortality rate, and complications related to ANP. Results: In comparison with Group C, Group A showed a significant decrease (P < 0.05) in serum level of MPO, MDA, PC, and I-FABP, with a significant increase (P < 0.05) in serum level of GPA, 6 h, 12 h, and 24 h after the start of ANP infusion. There was significant decrease (P < 0.05) in mean duration of noradrenaline infusion, the length of ICU stay and mortality rate in Group A in comparison with Group C. In Group A, seven patients had mean arterial blood pressure < 65 mmHg but respond to volume resuscitation, three patients serum sodium was 125–130 mmol/L. Conclusion: In cases of septic shock, concomitant administration of ANP with noradrenaline may have a protective effect against intestinal injury through a decrease in the level of intestinal hypoperfusion owing to its anti-inflammatory and antioxidant effect. PMID

  11. Intestinal expression of peptide transporter 1 (PEPT1) at different life stages of Japanese eel, Anguilla japonica.

    PubMed

    Ahn, Hyojin; Yamada, Yoshiaki; Okamura, Akihiro; Tsukamoto, Katsumi; Kaneko, Toyoji; Watanabe, Soichi

    2013-10-01

    The expression of peptide transporter 1 (PEPT1) was investigated at the different life stages of Japanese eel, Anguilla japonica. The cDNA encoding Japanese eel PEPT1 was cloned and sequenced. The hydrophilicity plot analysis of its deduced amino acid sequence showed high similarities with topological features of known PEPT1 molecules in other species. Tissue distribution analysis confirmed that PEPT1 mRNA was detected specifically in the anterior and posterior intestines of adult eel. In eel larvae at 13days post hatching (dph), PEPT1 mRNA expression was mainly detected in the intestinal tract regions. The trypsinogen mRNA was only detected in the gastric region including the pancreas. Intense immunoreaction for PEPT1 was observed in the apical membrane of the intestinal epithelial cells of both larval and adult eel. These results indicated that PEPT1 was an intestine-specific transporter, which was localized at the luminal side of the epithelial cells, suggesting that di/tri-peptide absorption via PEPT1 takes place in the eel intestine. According to the ontogenetic analyses by quantitative PCR, PEPT1 and trypsinogen mRNA expressions were simultaneously increased at 5-7 dph. It is thus assumed that nutrient absorption systems in the intestinal tracts of larvae become functional at this age.

  12. Alpha-Melanocyte Stimulating Hormone Protects against Cytokine-Induced Barrier Damage in Caco-2 Intestinal Epithelial Monolayers

    PubMed Central

    Váradi, Judit; Harazin, András; Fenyvesi, Ferenc; Réti-Nagy, Katalin; Gogolák, Péter; Vámosi, György; Bácskay, Ildikó; Fehér, Pálma; Ujhelyi, Zoltán; Vasvári, Gábor; Róka, Eszter; Haines, David; Deli, Mária A.; Vecsernyés, Miklós

    2017-01-01

    Alpha-melanocyte-stimulating hormone (α-MSH) is a potent anti-inflammatory peptide with cytoprotective effect in various tissues. The present investigation demonstrates the ability of α-MSH to interact with intestinal epithelial cell monolayers and mitigate inflammatory processes of the epithelial barrier. The protective effect of α-MSH was studied on Caco-2 human intestinal epithelial monolayers, which were disrupted by exposure to tumor necrosis factor-α and interleukin-1β. The barrier integrity was assessed by measuring transepithelial electric resistance (TEER) and permeability for marker molecules. Caco-2 monolayers were evaluated by immunohistochemistry for expression of melanocortin-1 receptor and tight junction proteins ZO-1 and claudin-4. The activation of nuclear factor kappa beta (NF-κB) was detected by fluorescence microscopy and inflammatory cytokine expression was assessed by flow cytometric bead array cytokine assay. Exposure of Caco-2 monolayers to proinflammatory cytokines lowered TEER and increased permeability for fluorescein and albumin, which was accompanied by changes in ZO-1 and claudin-4 immunostaining. α-MSH was able to prevent inflammation-associated decrease of TEER in a dose-dependent manner and reduce the increased permeability for paracellular marker fluorescein. Further immunohistochemistry analysis revealed proinflammatory cytokine induced translocation of the NF-κB p65 subunit into Caco-2 cell nuclei, which was inhibited by α-MSH. As a result the IL-6 and IL-8 production of Caco-2 monolayers were also decreased with different patterns by the addition of α-MSH to the culture medium. In conclusion, Caco-2 cells showed a positive immunostaining for melanocortin-1 receptor and α-MSH protected Caco-2 cells against inflammatory barrier dysfunction and inflammatory activation induced by tumor necrosis factor-α and interleukin-1β cytokines. PMID:28103316

  13. Biofilm mode of growth of Streptococcus intermedius favored by a competence-stimulating signaling peptide.

    PubMed

    Petersen, Fernanda C; Pecharki, Daniele; Scheie, Anne A

    2004-09-01

    Gram-positive and gram-negative bacteria use quorum sensing to coordinate population behavior. In several streptococci, quorum sensing mediated by competence-stimulating peptides (CSP) is associated with development of competence for transformation. We show here that a synthetic CSP favored the biofilm mode of growth of Streptococcus intermedius without affecting the rate of culture growth.

  14. GPR54 peptide agonists stimulate insulin secretion from murine, porcine and human islets.

    PubMed

    Bowe, James E; Foot, Victoria L; Amiel, Stephanie A; Huang, Gao Cai; Lamb, Morgan W; Lakey, Jonathan; Jones, Peter M; Persaud, Shanta J

    2012-01-01

    This study was designed to determine the effects of 10 and 13 amino acid forms of kisspeptin on dynamic insulin secretion from mammalian islets since it is not clear from published data whether the shorter peptide is stimulatory while the longer peptide inhibits insulin release. Insulin secretion was measured by radioimmunoassay following perifusion of human, pig, rat and mouse isolated islets with kisspeptin-10 or kisspeptin-13 in the presence of 20 mM glucose. Both peptides stimulated rapid, reversible potentiation of glucose-stimulated insulin secretion from islets of all species tested. These data indicate that both kisspeptin-10 and kisspeptin-13, which is an extension of kisspeptin-10 by three amino acids, act directly at islet β-cells of various species to potentiate insulin secretion, and suggest that inhibitory effects reported in earlier studies may reflect differences in experimental protocols.

  15. Transport of Antihypertensive Peptide RVPSL, Ovotransferrin 328-332, in Human Intestinal Caco-2 Cell Monolayers.

    PubMed

    Ding, Long; Wang, Liying; Zhang, Yan; Liu, Jingbo

    2015-09-23

    The objective of this study was to investigate the transepithelial transport of RVPSL (Arg-Val-Pro-Ser-Leu), an egg-white-derived peptide with angiotensin I-converting enzyme (ACE) inhibitory and antihypertensive activity, in human intestinal Caco-2 cell monolayers. Results revealed that RVPSL could be passively transported across Caco-2 cell monolayers. However, during the process of transport, 36.31% ± 1.22% of the initial RVPSL added to the apical side was degraded, but this degradation decreased to 23.49% ± 0.68% when the Caco-2 cell monolayers were preincubated with diprotin A (P < 0.001), suggesting that RVPSL had a low resistance to various brush border membrane peptidases. When transport from the apical side to the basolateral side was investigated, the apparent permeability coefficient (Papp) was (6.97 ± 1.11) × 10(-6) cm/s. The transport route of RVPSL appears to be the paracellular pathway via tight junctions, as only cytochalasin D, a disruptor of tight junctions (TJs), significantly increased the transport rate (P < 0.001). In addition, the relationship between the structure of RVPSL and transport across Caco-2 cell monolayers was studied by mutation of RVPSL. It was found that N-terminal Pro residues were more beneficial for transport of pentapeptides across Caco-2 cell monolayers than Arg and Val. Furthermore, RVPSL could be more easily transported as smaller peptides, especially in the form of dipeptides and tripeptides.

  16. Disrupted reproduction, estrous cycle, and circadian rhythms in female mice deficient in vasoactive intestinal peptide.

    PubMed

    Loh, D H; Kuljis, D A; Azuma, L; Wu, Y; Truong, D; Wang, H B; Colwell, C S

    2014-10-01

    The female reproductive cycle is gated by the circadian timing system and may be vulnerable to disruptions in the circadian system. Prior work suggests that vasoactive intestinal peptide (VIP)-expressing neurons in the suprachiasmatic nucleus (SCN) are one pathway by which the circadian clock can influence the estrous cycle, but the impact of the loss of this peptide on reproduction has not been assessed. In the present study, we first examine the impact of the genetic loss of the neuropeptide VIP on the reproductive success of female mice. Significantly, mutant females produce about half the offspring of their wild-type sisters even when mated to the same males. We also find that VIP-deficient females exhibit a disrupted estrous cycle; that is, ovulation occurs less frequently and results in the release of fewer oocytes compared with controls. Circadian rhythms of wheel-running activity are disrupted in the female mutant mice, as is the spontaneous electrical activity of dorsal SCN neurons. On a molecular level, the VIP-deficient SCN tissue exhibits lower amplitude oscillations with altered phase relationships between the SCN and peripheral oscillators as measured by PER2-driven bioluminescence. The simplest explanation of our data is that the loss of VIP results in a weakened SCN oscillator, which reduces the synchronization of the female circadian system. These results clarify one of the mechanisms by which disruption of the circadian system reduces female reproductive success.

  17. High affinity receptors for vasoactive intestinal peptide on a human glioma cell line

    SciTech Connect

    Nielsen, F.C.; Gammeltoft, S.; Westermark, B.; Fahrenkrug, J. )

    1990-11-01

    Vasoactive intestinal peptide (VIP) bound with high affinity (Kd 0.13 nmol/l) to receptors on the human glioma cell line U-343 MG Cl 2:6. The receptors bound the related peptides helodermin, PHM and secretin with 10, 400 and 5000 times lower affinity, respectively. Deamidated VIP (VIP-COOH) and (des-His1)VIP bound with 10 and 100 times lower affinity. The fragment VIP(7-28) displaced 25% of the receptor-bound {sup 125}I-VIP whereas VIP(16-28) and VIP(1-22-NH2) were inactive. The binding of {sup 125}I-VIP could be completely inhibited by 10 mumol/l of the antagonists (N-Ac-Tyr1,D-Phe2)GRF(1-29)-NH2, (pCl-D-Phe6,Leu17)VIP and VIP(10-28); in contrast, the antagonist L-8-K was inactive. Affinity labeling showed that VIP bound to proteins with Mr's of 75 kDa, 66 kDa and 50 kDa, respectively. Following binding, the peptide was rapidly internalized, and at steady-state only 20% of cell-associated {sup 125}I-VIP was bound to receptors on the cell surface. The internalized {sup 125}I-VIP was completely degraded to {sup 125}I-tyrosine which was released from the cells. Degradation of internalized {sup 125}I-VIP was significantly reduced by chloroquine phenanthroline and pepstatin-A. Surface binding and internalization of {sup 125}I-VIP was increased 3 times by phenanthroline, and pepstatin-A caused a 5 times increase in surface binding. Chloroquine reduced surface-bound {sup 125}I-VIP, but caused retention of internalized {sup 125}I-VIP.

  18. Protein kinase D1 mediates stimulation of DNA synthesis and proliferation in intestinal epithelial IEC-18 cells and in mouse intestinal crypts.

    PubMed

    Sinnett-Smith, James; Rozengurt, Nora; Kui, Robert; Huang, Carlos; Rozengurt, Enrique

    2011-01-07

    We examined whether protein kinase D1 (PKD1), the founding member of a new protein kinase family, plays a critical role in intestinal epithelial cell proliferation. Our results demonstrate that PKD1 activation is sustained, whereas that of PKD2 is transient in intestinal epithelial IEC-18 stimulated with the G(q)-coupled receptor agonists angiotensin II or vasopressin. PKD1 gene silencing utilizing small interfering RNAs dramatically reduced DNA synthesis and cell proliferation in IEC-18 cells stimulated with G(q)-coupled receptor agonists. To clarify the role of PKD1 in intestinal epithelial cell proliferation in vivo, we generated transgenic mice that express elevated PKD1 protein in the intestinal epithelium. Transgenic PKD1 exhibited constitutive catalytic activity and phosphorylation at the activation loop residues Ser(744) and Ser(748) and on the autophosphorylation site, Ser(916). To examine whether PKD1 expression stimulates intestinal cell proliferation, we determined the rate of crypt cell DNA synthesis by detection of 5-bromo-2-deoxyuridine incorporated into the nuclei of crypt cells of the ileum. Our results demonstrate a significant increase (p < 0.005) in DNA-synthesizing cells in the crypts of two independent lines of PKD1 transgenic mice as compared with non-transgenic littermates. Morphometric analysis showed a significant increase in the length and in the total number of cells per crypt in the transgenic PKD1 mice as compared with the non-transgenic littermates (p < 0.01). Thus, transgenic PKD1 signaling increases the number of cells per crypt by stimulating the rate of crypt cell proliferation. Collectively, our results indicate that PKD1 plays a role in promoting cell proliferation in intestinal epithelial cells both in vitro and in vivo.

  19. Impact of Intestinal Electrical Stimulation on Nutrient-Induced GLP-1 Secretion In Vivo

    PubMed Central

    Sandoval, Darleen; Dunki-Jacobs, Adam; Sorrell, Joyce; Seeley, Randy J.; D’Alessio, David D.

    2013-01-01

    Increases in L-cell release of GLP-1 are proposed to serve as a negative feedback signal for postprandial changes in gastric emptying and/or motility. Previous ex vivo data suggests that direct electrical stimulation (E-stim) of ileal segments stimulates secretion of GLP-1. This suggests potential feed-forward increases in GLP-1 driven by intestinal neuronal and/or motor activity. To determine if E-stim could increase GLP-1 levels in an in vivo setting, we administered E-stim and nutrients to male Long-Evans rats (300–350g) under general anesthesia. Nutrient infusion into the duodenum or ileum significantly increased plasma GLP-1 levels, but E-stim applied to these locations did not (p<0.05). However, the combination of E-stim and nutrient infusion, in either the ileum or duodenum, significantly increased plasma GLP-1 when compared to nutrient infusion alone (p<0.05), and this effect was not blocked by either norepinephrine or atropine. To test the impact of intestinal motor activity, the effect of extra-luminal mechanical stimulation (M-stim) on GLP-1 levels was assessed. In the duodenum, but not the ileum, M-stim plus nutrient infusion significantly increased GLP-1 over nutrient infusion or M-stim alone (p<0.05). Thus, both E- and M-stim of the duodenum, but only E-stim of the ileum augmented nutrient-stimulated GLP-1 release. These data demonstrate that factors beyond enteral nutrients could contribute to the regulation of GLP-1 secretion. PMID:23663526

  20. Lack of Effects of a Single High-Fat Meal Enriched with Vegetable n-3 or a Combination of Vegetable and Marine n-3 Fatty Acids on Intestinal Peptide Release and Adipokines in Healthy Female Subjects

    PubMed Central

    Narverud, Ingunn; Myhrstad, Mari C. W.; Herzig, Karl-Heinz; Karhu, Toni; Dahl, Tuva B.; Halvorsen, Bente; Ulven, Stine M.; Holven, Kirsten B.

    2016-01-01

    Peptides released from the small intestine and colon regulate short-term food intake by suppressing appetite and inducing satiety. Intake of marine omega-3 (n-3) fatty acids (FAs) from fish and fish oils is associated with beneficial health effects, whereas the relation between intake of the vegetable n-3 fatty acid α-linolenic acid and diseases is less clear. The aim of the present study was to investigate the postprandial effects of a single high-fat meal enriched with vegetable n-3 or a combination of vegetable and marine n-3 FAs with their different unsaturated fatty acid composition on intestinal peptide release and the adipose tissue. Fourteen healthy lean females consumed three test meals with different fat quality in a fixed order. The test meal consisted of three cakes enriched with coconut fat, linseed oil, and a combination of linseed and cod liver oil. The test days were separated by 2 weeks. Fasting and postprandial blood samples at 3 and 6 h after intake were analyzed. A significant postprandial effect was observed for cholecystokinin, peptide YY, glucose-dependent insulinotropic polypeptide, amylin and insulin, which increased, while leptin decreased postprandially independent of the fat composition in the high-fat meal. In conclusion, in healthy, young, lean females, an intake of a high-fat meal enriched with n-3 FAs from different origin stimulates intestinal peptide release without any difference between the different fat compositions. PMID:27630989

  1. Vascular, but not luminal, activation of FFAR1 (GPR40) stimulates GLP-1 secretion from isolated perfused rat small intestine

    PubMed Central

    Christensen, Louise W; Kuhre, Rune E; Janus, Charlotte; Svendsen, Berit; Holst, Jens J

    2015-01-01

    Glucagon-like peptide 1 (GLP-1) plays a central role in modern treatment of type 2 diabetes (T2DM) in the form of GLP-1 enhancers and GLP-1 mimetics. An alternative treatment strategy is to stimulate endogenous GLP-1 secretion from enteroendocrine L cells using a targeted approach. The G-protein-coupled receptor, FFAR1 (previously GPR40), expressed on L cells and activated by long-chain fatty acids (LCFAs) is a potential target. A link between FFAR1 activation and GLP-1 secretion has been demonstrated in cellular models and small-molecule FFAR1 agonists have been developed. In this study, we examined the effect of FFAR1 activation on GLP-1 secretion using isolated, perfused small intestines from rats, a physiologically relevant model allowing distinction between direct and indirect effects of FFAR1 activation. The endogenous FFAR1 ligand, linoleic acid (LA), and four synthetic FFAR1 agonists (TAK-875, AMG 837, AM-1638, and AM-5262) were administered through intraluminal and intra-arterial routes, respectively, and dynamic changes in GLP-1 secretion were evaluated. Vascular administration of 10 μmol/L TAK-875, 10 μmol/L AMG 837, 1 μmol/L and 0.1 μmol/L AM-1638, 1 μmol/L AM-6252, and 1 mmol/L LA, all significantly increased GLP-1 secretion compared to basal levels (P < 0.05), whereas luminal administration of LA and FFAR1 agonists was ineffective. Thus, both natural and small-molecule agonists of the FFAR1 receptor appear to require absorption prior to stimulating GLP-1 secretion, indicating that therapies based on activation of nutrient sensing may be more complex than hitherto expected. PMID:26381015

  2. Protease-activated receptor-2 stimulates intestinal epithelial chloride transport through activation of PLC and selective PKC isoforms.

    PubMed

    van der Merwe, Jacques Q; Moreau, France; MacNaughton, Wallace K

    2009-06-01

    Serine proteases play important physiological roles through their activity at G protein-coupled protease-activated receptors (PARs). We examined the roles that specific phospholipase (PL) C and protein kinase (PK) C (PKC) isoforms play in the regulation of PAR(2)-stimulated chloride secretion in intestinal epithelial cells. Confluent SCBN epithelial monolayers were grown on Snapwell supports and mounted in modified Ussing chambers. Short-circuit current (I(sc)) responses to basolateral application of the selective PAR(2) activating peptide, SLIGRL-NH(2), were monitored as a measure of net electrogenic ion transport caused by PAR(2) activation. SLIGRL-NH(2) induced a transient I(sc) response that was significantly reduced by inhibitors of PLC (U73122), phosphoinositol-PLC (ET-18), phosphatidylcholine-PLC (D609), and phosphatidylinositol 3-kinase (PI3K; LY294002). Immunoblot analysis revealed the phosphorylation of both PLCbeta and PLCgamma following PAR(2) activation. Pretreatment of the cells with inhibitors of PKC (GF 109203X), PKCalpha/betaI (Gö6976), and PKCdelta (rottlerin), but not PKCzeta (selective pseudosubstrate inhibitor), also attenuated this response. Cellular fractionation and immunoblot analysis, as well as confocal immunocytochemistry, revealed increases of PKCbetaI, PKCdelta, and PKCepsilon, but not PKCalpha or PKCzeta, in membrane fractions following PAR(2) activation. Pretreatment of the cells with U73122, ET-18, or D609 inhibited PKC activation. Inhibition of PI3K activity only prevented PKCdelta translocation. Immunoblots revealed that PAR(2) activation induced phosphorylation of both cRaf and ERK1/2 via PKCdelta. Inhibition of PKCbetaI and PI3K had only a partial effect on this response. We conclude that basolateral PAR(2)-induced chloride secretion involves activation of PKCbetaI and PKCdelta via a PLC-dependent mechanism resulting in the stimulation of cRaf and ERK1/2 signaling.

  3. Glycans in the intestinal peptide transporter PEPT1 contribute to function and protect from proteolysis.

    PubMed

    Stelzl, Tamara; Geillinger-Kästle, Kerstin Elisabeth; Stolz, Jürgen; Daniel, Hannelore

    2017-03-23

    Despite the fact that many membrane proteins carry extracellular glycans, little is known about whether the glycan chains also affect protein function. We recently demonstrated that the proton-coupled oligopeptide transporter 1 (PEPT1) in the intestine is glycosylated at six asparagine residues (N50, N406, N439, N510, N515, N532). Mutagenesis-induced disruption of the individual N-glycosylation site N50, which is highly conserved among mammals, was detected to significantly enhance the PEPT1 mediated inward transport of peptides. Here, we show for the murine protein, that the inhibition of glycosylation at sequon N50 by substituting N50 with glutamine, lysine or cysteine, or by replacing S52 with alanine, equally altered PEPT1 transport kinetics in oocytes. Further, we provide evidence that the uptake of [(14)C]-glycyl-sarcosine in immortalized murine small intestinal (Mode-K) or colonic epithelial (PTK-6) cells stably expressing the PEPT1 transporter N50Q is also significantly increased relative to the wild type protein. By using electrophysiological recordings and tracer flux studies, we further demonstrate that the rise in transport velocity observed for PEPT1 N50Q is bidirectional. In line with these findings, we show that attachment of biotin derivatives, comparable in weight to 2-4 monosaccharides, to the PEPT1 N50C transporter slows down the transport velocity. In addition, our experiments provide strong evidence that glycosylation of PEPT1 confers resistance against proteolytic cleavage by proteinase K, while a remarkable intrinsic stability against trypsin, even in absence of N-linked glycans, was detected.

  4. A pilot study examining the relationship among Crohn disease activity, glucagon-like peptide-2 signalling and intestinal function in pediatric patients

    PubMed Central

    Sigalet, David L; Kravarusic, Dragan; Butzner, Decker; Hartmann, Bolette; Holst, Jens J; Meddings, Jon

    2013-01-01

    BACKGROUND/OBJECTIVES: The relationship between the enteroendocrine hormone glucagon-like peptide 2 (GLP-2) and intestinal inflammation is unclear. GLP-2 promotes mucosal growth, decreases permeability and reduces inflammation in the intestine; physiological stimulation of GLP-2 release is triggered by nutrient contact. The authors hypothesized that ileal Crohn disease (CD) affects GLP-2 release. METHODS: With ethics board approval, pediatric patients hospitalized with CD were studied; controls were recruited from local schools. Inclusion criteria were endoscopy-confirmed CD (primarily of the small intestine) with a disease activity index >150. Fasting and post-prandial GLP-2 levels and quantitative urinary recovery of orally administered 3-O-methyl-glucose (active transport) and lactulose/mannitol (passive) were quantified during the acute and remission phases. RESULTS: Seven patients (mean [± SD] age 15.3±1.3 years) and 10 controls (10.3±1.6 years) were studied. In patients with active disease, fasting levels of GLP-2 remained stable but postprandial levels were reduced. Patients with active disease exhibited reduced glucose absorption and increased lactulose/mannitol recovery; all normalized with disease remission. The change in the lactulose/mannitol ratio was due to both reduced lactulose and increased mannitol absorption. CONCLUSIONS: These findings suggest that pediatric patients with acute ileal CD have decreased postprandial GLP-2 release, reduced glucose absorption and increased intestinal permeability. Healing of CD resulted in normalization of postprandial GLP-2 release and mucosal functioning (nutrient absorption and permeability), the latter due to an increase in mucosal surface area. These findings have implications for the use of GLP-2 and feeding strategies as a therapy in CD patients; further studies of the effects of inflammation and the GLP-2 axis are recommended. PMID:24106731

  5. alpha-Melanocyte-stimulating hormone and oxytocin: a peptide signalling cascade in the hypothalamus.

    PubMed

    Sabatier, N

    2006-09-01

    alpha-Melanocyte-stimulating hormone (alpha-MSH) and oxytocin share remarkable similarities of effects on behaviour in rats; in particular, they both inhibit feeding behaviour and stimulate sexual behaviour. Recently, we showed that alpha-MSH interacts with the magnocellular oxytocin system in the supraoptic nucleus; alpha-MSH induces the release of oxytocin from the dendrites of magnocellular neurones but it inhibits the secretion of oxytocin from their nerve terminals in the posterior pituitary. This effect of alpha-MSH on supraoptic nucleus oxytocin neurones is remarkable for two reasons. First, it illustrates the capacity of magnocellular neurones to differentially regulate peptide release from dendrites and axons and, second, it emphasises the putative role of magnocellular neurones as a major source of central oxytocin release, and as a likely substrate of some oxytocin-mediated behaviours. The ability of peptides to differentially control secretion from different compartments of their targets indicates one way by which peptide signals might have a particularly significant effect on neuronal circuitry. This suggests a possible explanation for the striking way in which some peptides can influence specific, complex behaviours.

  6. Growth factor based therapies and intestinal disease: is glucagon-like peptide-2 the new way forward?

    PubMed

    Yazbeck, Roger; Howarth, Gordon S; Abbott, Catherine A

    2009-04-01

    Inflammatory bowel disease (IBD) is a chronic, debilitating disease associated with severe damage to the intestinal mucosa. Glucagon-like peptide-2 (GLP-2) is a potent and specific gastrointestinal growth factor that is demonstrating therapeutic potential for the prevention or treatment of an expanding number of intestinal diseases, including short bowel syndrome (SBS), small bowel enteritis and IBD. The biological activity of GLP-2 is limited due to proteolytic inactivation by the protease dipeptidyl peptidase (DP)IV. Inhibitors of DPIV activity may represent a novel strategy to prolong the growth promoting actions of GLP-2. This review outlines evidence for the clinical application of GLP-2, its degradation resistant analogue, Teduglutide, and novel DPIV inhibitors in efficacy studies utilizing pre-clinical models of intestinal damage, in particular IBD.

  7. Enterococcus faecium stimulates human neutrophils via the formyl-peptide receptor 2.

    PubMed

    Bloes, Dominik Alexander; Otto, Michael; Peschel, Andreas; Kretschmer, Dorothee

    2012-01-01

    The human formyl-peptide receptor 2 (FPR2/ALX) senses phenol-soluble modulin (PSM) peptide toxins produced by pathogenic staphylococcal species and plays a crucial role in directing neutrophil influx during staphylococcal infection. However, it has remained unclear if FPR2 responds also to molecules from other bacterial pathogens. Here we analyzed a variety of gram-positive and gram-negative pathogens and found that apart from staphylococci only certain enterococcal strains have the capacity to stimulate FPR2/ALX. Most of the analyzed Enterococcus faecium but only sporadic Enterococcus faecalis strains released FPR2/ALX-stimulating molecules leading to neutrophil calcium ion fluxes, chemotaxis, and complement receptor upregulation. Among ten test strains vancomycin-resistant E. faecium had a significantly higher capacity to stimulate FPR2/ALX than vancomycin-susceptible strains, suggesting an association of strong FPR2/ALX activation with health-care associated strains. The enterococcal FPR2/ALX agonists were found to be peptides or proteins, which appear, however, to be unrelated to staphylococcal PSMs in sequence and physicochemical properties. Enterococci are among the most frequent invasive bacterial pathogens but the basis of enterococcal virulence and immune activation has remained incompletely understood. Our study indicates that previously unrecognized proteinaceous agonists contribute to Enterococcus-host interaction and underscores the importance of FPR2/ALX in host defense against major endogenous bacterial pathogens.

  8. Neuropeptide Y-like immunoreactivity in rat cranial parasympathetic neurons: coexistence with vasoactive intestinal peptide and choline acetyltransferase

    SciTech Connect

    Leblanc, G.C.; Trimmer, B.A.; Landis, S.C.

    1987-05-01

    Neuropeptide Y (NPY) is widely distributed in the sympathetic nervous system, where it is colocalized with norepinephrine. The authors report here that NPY-immunoreactive neurons are also abundant in three cranial parasympathetic ganglia, the otic, sphenopalatine, and ciliary, in the rat measured by radioimmunoassay. High-performance liquid chromatographic analysis of the immunoreactive material present in the otic ganglion indicates that this material is very similar to porcine NPY and indistinguishable from the NPY-like immunoreactivity present in rat sympathetic neurons. These findings raise the possibility that NPY acts as a neuromodulator in the parasympathetic as well as the sympathetic nervous system. In contrast to what had been observed for sympathetic neurons, NPY-immunoreactive neurons in cranial parasympathetic ganglia do not contain detectable catecholamines or tyrosine hydroxylase immunoreactivity, and many do contain immunoreactivity for vasoactive intestinal peptide and/or choline acetyltransferase. These findings suggest that there is no simple rule governing coexpression of NPY with norepinephrine, acetylcholine, or vasoactive intestinal peptide in autonomic neurons. Further, while functional studies have indicated that NPY exerts actions on the peripheral vasculature which are antagonistic to those of acetylcholine and vasoactive intestinal peptide, the present results raise the possibility that these three substances may have complementary effects on other target tissues.

  9. Enteral peptide formulas inhibit radiation induced enteritis and apoptosis in intestinal epithelial cells and suppress the expression and function of Alzheimer's and cell division control gene products

    SciTech Connect

    Cope, F.O. ); Issinger, O.G. ); McArdle, A.H. ); Shapiro, J.; Tomei, L.D. )

    1991-03-15

    Studies have shown that patients receiving enteral peptide formulas prior to irradiation have a significantly reduced incidence of enteritis and express a profound increase in intestinal cellularity. Two conceptual approaches were taken to describe this response. First was the evaluation in changes in programmed intestinal cell death and secondly the evaluation of a gene product controlling cell division cycling. This study provided a relationship between the ratio of cell death to cell formulations. The results indicate that in the canine and murine models, irradiation induces expression of the Alzheimer's gene in intestinal crypt cells, while the incidence of apoptosis in apical cells is significantly increased. The use of peptide enteral formulations suppresses the expression of the Alzheimer's gene in crypt cells, while apoptosis is eliminated in the apical cells of the intestine. Concomitantly, enteral peptide formulations suppress the function of the CK-II gene product in the basal and baso-lateral cells of the intestine. These data indicate that although the mitotic index is significantly reduced in enterocytes, this phenomenon alone is not sufficient to account for the peptide-induced radio-resistance of the intestine. The data also indicate a significant reduction of normal apoptosis in the upper lateral and apical cells of the intestinal villi. Thus, the ratio of cell death to cell replacement is significantly decreased resulting in an increase in villus height and hypertrophy of the apical villus cells. Thus, peptide solutions should be considered as an adjunct treatment both in radio- and chemotherapy.

  10. Effect of Glucagon-Like Peptide 2 on Hepatic, Renal, and Intestinal Disposition of 1-Chloro-2,4-dinitrobenzene

    PubMed Central

    Villanueva, Silvina S. M.; Perdomo, Virginia G.; Ruiz, María L.; Rigalli, Juan P.; Arias, Agostina; Luquita, Marcelo G.; Vore, Mary; Catania, Viviana A.

    2012-01-01

    The ability of the liver, small intestine, and kidney to synthesize and subsequently eliminate dinitrophenyl-S-glutathione (DNP-SG), a substrate for multidrug resistance-associated protein 2 (Mrp2), was assessed in rats treated with glucagon-like peptide 2 (GLP-2, 12 μg/100 g b.wt. s.c. every 12 h for 5 consecutive days). An in vivo perfused jejunum model with simultaneous bile and urine collection was used. A single intravenous dose of 30 μmol/kg b.wt. 1-chloro-2,4-dinitrobenzene (CDNB) was administered, and its conjugate, DNP-SG, and dinitrophenyl cysteinyl glycine (DNP-CG), resulting from the action of γ-glutamyltransferase on DNP-SG, were determined in bile, intestinal perfusate, and urine by high-performance liquid chromatography. Tissue content of DNP-SG was also assessed in liver, intestine, and kidneys. Biliary excretion of DNP-SG+DNP-CG was decreased in GLP-2 rats with respect to controls. In contrast, their intestinal excretion was substantially increased, whereas urinary elimination was not affected. Western blot and real-time polymerase chain reaction studies revealed preserved levels of Mrp2 protein and mRNA in liver and renal cortex and a significant increase in intestine in response to GLP-2 treatment. Tissue content of DNP-SG detected 5 min after CDNB administration was decreased in liver, increased in intestine, and unchanged in kidney in GLP-2 versus control group, consistent with GLP-2-induced down-regulation of expression of glutathione transferase (GST) Mu in liver and up-regulation of GST-Alpha in intestine at both protein and mRNA levels. In conclusion, GLP-2 induced selective changes in hepatic and intestinal disposition of a common GST and Mrp2 substrate administered systemically that could be of pharmacological or toxicological relevance under therapeutic treatment conditions. PMID:22453052

  11. Effects of vasoactive intestinal peptide on vascular conductance are unaffected by anesthesia

    SciTech Connect

    Bouder, T.G.; Huffman, L.J.; Hedge, G.A. )

    1988-12-01

    In rats anesthetized with ketamine and pentobarbital (KET/PB), vasoactive intestinal peptide (VIP) increases vascular conductance (VC) in the salivary gland, pancreas, and thyroid gland, whereas no changes in VC are observed in a number of other organs. Because anesthesia may alter the responsiveness of physiological systems, we compared the effects of VIP on organ VC in conscious or anesthetized rats. Chronically catheterized rats were studied in the conscious state or 30 min after induction of anesthesia with KET/PB, isoflurane, or Inactin. Blood flows were measured by the reference sample version of the radioactive microsphere (MS) technique using two MS injections ({sup 141}Ce-MS/{sup 85}Sr-MS). Mean arterial blood pressure was monitored and used in the calculation of VC. Organ VCs were similar under basal conditions in conscious and anesthetized rats. VIP infusion caused systemic hypotension and increased VCs in the salivary gland, pancreas, and thyroid gland, and these responses were largely unaffected by anesthesia. These results indicate that the anesthetics used do not alter basal VC or the responsiveness of the vasculature to exogenous VIP.

  12. Distribution of hypothalamic vasoactive intestinal peptide immunoreactive neurons in the male native Thai chicken.

    PubMed

    Kamkrathok, Boonyarit; Sartsoongnoen, Natagarn; Prakobsaeng, Nattiya; Rozenboim, Israel; Porter, Tom E; Chaiseha, Yupaporn

    2016-08-01

    Avian prolactin (PRL) secretion is under stimulatory control by the PRL-releasing factor (PRF), vasoactive intestinal peptide (VIP). The neuroendocrine regulation of the avian reproductive system has been extensively studied in females. However, there are limited data in males. The aim of this study was to elucidate the VIPergic system and its relationship to PRL and testosterone (T) in the male native Thai chicken. The distributions of VIP-immunoreactive (-ir) neurons and fibers were determined by immunohistochemistry. Changes in VIP-ir neurons within the nucleus inferioris hypothalami (IH) and nucleus infundibuli hypothalami (IN) areas were compared across the reproductive stages. Plasma levels of PRL and T were determined by enzyme-linked immunosorbent assay and then compared across the reproductive stages. The results revealed that the highest accumulations of VIP-ir neurons were concentrated only within the IH-IN, and VIP-ir neurons were not detected within other hypothalamic nuclei. Within the IH-IN, VIP-ir neurons were low in premature and aging males and markedly increased in mature males. Changes in VIP-ir neurons within the IH-IN were directly mirrored with changes in PRL and T levels across the reproductive stages. These results suggested that VIP neurons in the IH-IN play a regulatory role in year-round reproductive activity in males. The present study also provides additional evidence that VIP is the PRF in non-seasonal, continuously breeding equatorial species.

  13. Acute effects of the glucagon-like peptide 2 analogue, teduglutide, on intestinal adaptation in short bowel syndrome.

    PubMed

    Thymann, Thomas; Stoll, Barbara; Mecklenburg, Lars; Burrin, Douglas G; Vegge, Andreas; Qvist, Niels; Eriksen, Thomas; Jeppesen, Palle B; Sangild, Per T

    2014-06-01

    Neonatal short bowel syndrome following massive gut resection is associated with malabsorption of nutrients. The intestinotrophic factor glucagon-like peptide 2 (GLP-2) improves gut function in adult patients with short bowel syndrome, but its effect in pediatric patients remains unknown. Our objective was to test the efficacy of the long-acting synthetic human GLP-2 analogue, teduglutide (ALX-0600), in a neonatal piglet jejunostomy model. Two-day-old pigs were subjected to resection of 50% of the small intestine (distal part), and the remnant intestine was exteriorized on the abdominal wall as a jejunostomy. All pigs were given total parenteral nutrition for 7 days and a single daily injection of the following doses of teduglutide: 0.01 (n = 6), 0.02 (n = 6), 0.1 (n = 5), or 0.2 mg · kg · day (n = 6), and compared with placebo (n = 9). Body weight increment was similar for all 4 teduglutide groups but higher than placebo (P < 0.05). There was a dose-dependent increase in weight per length of the remnant intestine (P < 0.01) and fractional protein synthesis rate in the intestine was increased in the 0.2 mg · kg · day group versus placebo (P < 0.001); however, functional and structural endpoints including activity of digestive enzymes, absorption of enteral nutrients, and immunohistochemistry (Ki67, villin, FABP2, ChgA, and GLP-2R) were not affected by the treatment. Teduglutide induces trophicity on the remnant intestine but has limited acute effects on functional endpoints. Significant effects of teduglutide on gut function may require a longer adaptation period and/or a more frequent administration of the peptide. In perspective, GLP-2 or its analogues may be relevant to improve intestinal adaptation in pediatric patients with short bowel syndrome.

  14. Targeted Melanoma Imaging and Therapy with Radiolabeled Alpha-Melanocyte Stimulating Hormone Peptide Analogues

    PubMed Central

    Quinn, Thomas; Zhang, Xiuli; Miao, Yubin

    2010-01-01

    Radiolabeled alpha-melanocyte stimulating hormone (α-MSH) analogues have been used to define the expression, affinity and function of the melanocortin-1 receptor (MC1-R). The MC1-R is one of a family of five G-protein linker receptors, which is primarily involved in regulation of skin pigmentation. Over-expression of the MC1-R on melanoma tumor cells has made it an attractive target for the development of α-MSH peptide based imaging and therapeutic agents. Initially, the native α-MSH peptide was radiolabeled directly, but it suffered from low specific activity and poor stability. The addition of non-natural amino acids yielded α-MSH analogues with greater MC-1R affinity and stability. Furthermore, peptide cyclization via disulfide and lactam bond formation as well as site-specific metal coordination resulted in additional gains in receptor affinity and peptide stability in vitro and in vivo. Radiochemical stability of the α-MSH analogues was improved through the conjugation of metal chelators to the peptide’s N-terminus or lysine residues for radionuclide coordination. In vitro cell binding studies demonstrated that the radiolabeled α-MSH analogues had low to subnanomolar affinities for the MC1-R. Biodistribution and imaging studies in the B16 mouse melanoma modeled showed rapid tumor uptake of the radiolabeled peptides, with the cyclic peptides demonstrating prolonged tumor retention. Cyclic α-MSH analogues labeled with beta and alpha emitting radionuclides demonstrated melanoma therapeutic efficacy in the B16 melanoma mouse model. Strong pre-clinical imaging and therapy data highlight the clinical potential use of radiolabeled α-MSH peptides for melanoma imaging and treatment of disseminated disease. PMID:20467398

  15. Clonidine and lidamidine (WHR-1142) stimulate sodium and chloride absorption in the rabbit intestine.

    PubMed

    Durbin, T; Rosenthal, L; McArthur, K; Anderson, D; Dharmsathaphorn, K

    1982-06-01

    The effects of clonidine and lidamidine on ion transport in the intestine of the rabbit were determined. In the ileum both clonidine (10(-6) M) and lidamidine (10(-3) M) (a) decreased the short circuit current (-1.9 +/- 0.3 and -2.0 +/- 0.4 muEq/h . cm2, respectively) and potential difference; (b) increased net sodium absorption (2.0 +/- 0.6 and 1.8 +/- 0.4 muEq/h . cm2) and chloride absorption (3.4 +/- 0.5 and 3.4 +/- 0.6 muEq/h . cm2); and (c) increased tissue conductance (8.7 +/- 1.7 and 10.0 +/- 1.6 mmho/cm2). The increase in net sodium and chloride absorption was primarily due to an increase in mucosal-to-serosal movement of the ions and a decrease in serosal-to-mucosal movement of chloride. The action of clonidine on the short circuit current was quantitatively similar to the action of epinephrine. Both were readily reversed by yohimbine, a specific alpha 2-adrenergic antagonist. Further, methoxamine, an alpha 1-adrenergic agonist has no effect on the short circuit current up to the concentration of 10(-5) M; and prazosin, an alpha 1-adrenergic antagonist, did not affect the change of the short circuit current induced by epinephrine. The results indicate the presence of alpha 2-adrenergic receptors on the intestine and suggest that alpha 2-adrenergic stimulation may account for the effect of epinephrine on ion transport. Lidamidine was studied because it is structurally related to clonidine and has many similar actions. Yohimbine transiently reversed the effect of lidamidine. alpha 1-Adrenergic or dopaminergic antagonists did not reverse the effect of lidamidine, suggesting that it may affect alpha 2-adrenergic receptors. The results indicate that both clonidine and lidamidine stimulate electrolyte absorption and may be clinically useful.

  16. Direct demonstration of guanine nucleotide sensitive receptors for vasoactive intestinal peptide in the anterior lobe of the rat pituitary gland

    SciTech Connect

    Agui, T.; Matsumoto, K. )

    1990-05-01

    The vasoactive intestinal peptide (VIP) receptors were identified on the membranes from the rat anterior pituitary gland with ({sup 125}I)VIP. The dissociation constant (Kd) and the maximal binding capacity (Bmax) values were estimated from the competitive inhibition data. The Kd and Bmax values were 1.05 +/- 0.75 nM and 103 +/- 11 fmol/mg protein, respectively. The order of molar potency of related peptides to inhibit ({sup 125}I)VIP binding was VIP greater than peptide histidine isoleucine (PHI) greater than secretin greater than glucagon. Glucagon was not effective to inhibit the binding. ({sup 125}I)VIP binding was effectively inhibited by the addition of guanine nucleotides. The order of molar potency to inhibit the binding was Gpp(NH)p greater than GTP greater than GDP greater than GMP greater than ATP. These results directly suggest the coupling of VIP receptors with guanine nucleotide binding proteins in the anterior pituitary gland.

  17. Modulation of chicken intestinal immune gene expression by small cationic peptides as feed additives during the first week posthatch

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have been investigating modulation strategies tailored around the selective stimulation of the host’s immune system as an alternative to direct targeting of microbial pathogens by antibiotics. One such approach is the use of a group of small cationic peptides (BT) produced by a Gram-positive soi...

  18. The Intestinal Peptide Transporter PEPT1 Is Involved in Food Intake Regulation in Mice Fed a High-Protein Diet

    PubMed Central

    Sailer, Manuela; Daniel, Hannelore

    2011-01-01

    High-protein diets are effective in achieving weight loss which is mainly explained by increased satiety and thermogenic effects. Recent studies suggest that the effects of protein-rich diets on satiety could be mediated by amino acids like leucine or arginine. Although high-protein diets require increased intestinal amino acid absorption, amino acid and peptide absorption has not yet been considered to contribute to satiety effects. We here demonstrate a novel finding that links intestinal peptide transport processes to food intake, but only when a protein-rich diet is provided. When mice lacking the intestinal peptide transporter PEPT1 were fed diets containing 8 or 21 energy% of protein, no differences in food intake and weight gain were observed. However, upon feeding a high-protein (45 energy%) diet, Pept1−/− mice reduced food intake much more pronounced than control animals. Although there was a regain in food consumption after a few days, no weight gain was observed which was associated with a reduced intestinal energy assimilation and increased fecal energy losses. Pept1−/− mice on high-protein diet displayed markedly reduced plasma leptin levels during the period of very low food intake, suggesting a failure of leptin signaling to increase energy intake. This together with an almost two-fold elevated plasma arginine level in Pept1−/− but not wildtype mice, suggests that a cross-talk of arginine with leptin signaling in brain, as described previously, could cause these striking effects on food intake. PMID:22031831

  19. Glucagon-Like Peptide-2 Regulates Release of Chylomicrons From the Intestine

    PubMed Central

    Dash, Satya; Xiao, Changting; Morgantini, Cecilia; Connelly, Philip W.; Patterson, Bruce W.; Lewis, Gary F.

    2015-01-01

    BACKGROUND & AIMS The intestine efficiently incorporates and rapidly secretes dietary fat as chylomicrons (lipoprotein particles comprising triglycerides, phospholipids, cholesterol, and proteins) that contain the apolipoprotein isoform apoB-48. The gut can store lipids for many hours after their ingestion, and release them in chylomicrons in response to oral glucose, sham feeding, or unidentified stimuli. The gut hormone glucagon-like peptide-2 (GLP-2) facilitates intestinal absorption of lipids, but its role in chylomicron secretion in human beings is unknown. METHODS We performed a randomized, single-blind, cross-over study, with 2 study visits 4 weeks apart, to assess the effects of GLP-2 administration on triglyceride-rich lipoprotein (TRL) apoB-48 in 6 healthy men compared with placebo. Subjects underwent constant intraduodenal feeding, with a pancreatic clamp and primed constant infusion of deuterated leucine. In a separate randomized, single-blind, cross-over validation study, 6 additional healthy men ingested a high-fat meal containing retinyl palmitate and were given either GLP-2 or placebo 7 hours later with measurement of TRL triglyceride, TRL retinyl palmitate, and TRL apoB-48 levels. RESULTS GLP-2 administration resulted in a rapid (within 30 minutes) and transient increase in the concentration of TRL apoB-48, compared with placebo (P = .03). Mathematic modeling of stable isotope enrichment and the mass of the TRL apoB-48 suggested that the increase resulted from the release of stored, presynthesized apoB-48 from the gut. In the validation study, administration of GLP-2 at 7 hours after the meal, in the absence of additional food intake, robustly increased levels of TRL triglycerides (P = .007), TRL retinyl palmitate (P = .002), and TRL apoB-48 (P = .04) compared with placebo. CONCLUSIONS Administration of GLP-2 to men causes the release of chylomicrons that comprise previously synthesized and stored apoB-48 and lipids. This transiently increases TRL

  20. C-peptide exhibits a late induction effect on matrix metallopeptidase-9 in high glucose-stimulated rat mesangial cells

    PubMed Central

    Wang, Junxia; Li, Yanning; Xu, Mingzhi; Li, Dandan; Wang, Yu; Qi, Jinsheng; He, Kunyu

    2016-01-01

    Insufficient matrix metalloproteinase (MMP)-9 and MMP-2 is considered to be a contributor of extracellular matrix (ECM) accumulation in diabetic nephropathy (DN). C-peptide can reverse fibrosis, thus exerting a beneficial effect on DN. Whether C-peptide induces MMP-9 and MMP-2 to reverse ECM accumulation is not clear. In the present study, in order to determine ECM metabolism, rat mesangial cells were treated with high glucose (HG) and C-peptide intervention, then the early and late effects of C-peptide on HG-affected MMP-9 and MMP-2 were evaluated. Firstly, it was confirmed that HG mainly suppressed MMP-9 expression levels. Furthermore, C-peptide treatment induced MMP-9 expression at 6 h and suppressed it at 24 h, revealing the early dual effects of C-peptide on MMP-9 expression. Subsequently, significant increase in MMP-9 expression at 72, 96 and 120 h C-peptide treatment was observed. These changes in MMP-9 protein content confirmed its expression changes following late C-peptide treatment. Furthermore, at 96 and 120 h C-peptide treatment reversed the HG-inhibited MMP-9 secretion, further indicating the late induction effect of C-peptide on MMP-9. The present results demonstrated that C-peptide exerted a late induction effect on MMP-9 in HG-stimulated rat mesangial cells, which may be associated with the underlying mechanism of C-peptide's reversal effects on DN. PMID:28101192

  1. Guanylin peptides regulate electrolyte and fluid transport in the Gulf toadfish (Opsanus beta) posterior intestine.

    PubMed

    Ruhr, Ilan M; Bodinier, Charlotte; Mager, Edward M; Esbaugh, Andrew J; Williams, Cameron; Takei, Yoshio; Grosell, Martin

    2014-11-01

    The physiological effects of guanylin (GN) and uroguanylin (UGN) on fluid and electrolyte transport in the teleost fish intestine have yet to be thoroughly investigated. In the present study, the effects of GN, UGN, and renoguanylin (RGN; a GN and UGN homolog) on short-circuit current (Isc) and the transport of Cl-, Na+, bicarbonate (HCO3-), and fluid in the Gulf toadfish (Opsanus beta) intestine were determined using Ussing chambers, pH-stat titration, and intestinal sac experiments. GN, UGN, and RGN reversed the Isc of the posterior intestine (absorptive-to-secretory), but not of the anterior intestine. RGN decreased baseline HCO3- secretion, but increased Cl- and fluid secretion in the posterior intestine. The secretory response of the posterior intestine coincides with the presence of basolateral NKCC1 and apical cystic fibrosis transmembrane conductance regulator (CFTR), the latter of which is lacking in the anterior intestine and is not permeable to HCO3- in the posterior intestine. However, the response to RGN by the posterior intestine is counterintuitive given the known role of the marine teleost intestine as a salt- and water-absorbing organ. These data demonstrate that marine teleosts possess a tissue-specific secretory response, apparently associated with seawater adaptation, the exact role of which remains to be determined.

  2. Novel alpha-melanocyte stimulating hormone peptide analogues with high candidacidal activity.

    PubMed

    Grieco, Paolo; Rossi, Claudia; Colombo, Gualtiero; Gatti, Stefano; Novellino, Ettore; Lipton, James M; Catania, Anna

    2003-02-27

    alpha-Melanocyte stimulating hormone (alpha-MSH) is an endogenous linear tridecapeptide with potent antiinflammatory effects. We recently demonstrated that alpha-MSH and its C-terminal sequence Lys-Pro-Val (alpha-MSH (11-13)) have antimicrobial effects against two major and representative pathogens: Staphylococcus aureus and Candida albicans. In an attempt to improve the candidacidal activity of alpha-MSH and to better understand the peptide structure-antifungal activity relations, we designed and synthesized novel peptide analogues. Because previous data suggested that antimicrobial effects of alpha-MSH were receptor-mediated, we chose to focus on the sequence alpha-MSH (6-13), which contains the invariant core sequence His-Phe-Arg-Trp (6-9) that is important for binding to the known melanocortin receptors and also contains the sequence Lys-Pro-Val (11-13) that is known to be important for antimicrobial activity. In this structure-activity study, we discovered several compounds that have greater candidacidal activity than alpha-MSH. The peptide [d-Nal-7,Phe-12]-alpha-MSH (6-13) was the most potent of the analogues tested. The present results are very encouraging because they show the great potential of these peptides as a truly novel class of candidacidal compounds.

  3. Antimicrobial peptides trigger a division block in Escherichia coli through stimulation of a signalling system

    PubMed Central

    Yadavalli, Srujana S.; Carey, Jeffrey N.; Leibman, Rachel S.; Chen, Annie I.; Stern, Andrew M.; Roggiani, Manuela; Lippa, Andrew M.; Goulian, Mark

    2016-01-01

    Antimicrobial peptides are an important component of the molecular arsenal employed by hosts against bacteria. Many bacteria in turn possess pathways that provide protection against these compounds. In Escherichia coli and related bacteria, the PhoQ/PhoP signalling system is a key regulator of this antimicrobial peptide defence. Here we show that treating E. coli with sublethal concentrations of antimicrobial peptides causes cells to filament, and that this division block is controlled by the PhoQ/PhoP system. The filamentation results from increased expression of QueE, an enzyme that is part of a tRNA modification pathway but that, as we show here, also affects cell division. We also find that a functional YFP–QueE fusion localizes to the division septum in filamentous cells, suggesting QueE blocks septation through interaction with the divisome. Regulation of septation by PhoQ/PhoP may protect cells from antimicrobial peptide-induced stress or other conditions associated with high-level stimulation of this signalling system. PMID:27471053

  4. Effect of vasoactive intestinal peptide on the wound healing of alkali-burned corneas

    PubMed Central

    Tuncel, Nese; Yildirim, Nilgun; Gurer, Firdevs; Basmak, Hikmet; Uzuner, Kubilay; Sahinturk, Varol; Gursoy, Huseyin

    2016-01-01

    AIM To study the effect of vasoactive intestinal peptide (VIP) on wound healing in experimental alkali burns of the cornea. METHODS Twenty-seven albino rabbits, weighing 3.2±0.75 kg were used. Alkali burns were induced on corneas by applying 10 mm Whatman paper No:50 soaked in 1 mol/L NaOH. They have further classified into 5 groups as follows: 1) control group given no treatment (n=5); 2) VIP given subconjunctivally (n=6); 3) VIP injected into anterior chamber (n=6); 4) NaCl 0.9% given subconjunctivally (n=5); 5) NaCl 0.9% given into the anterior chamber (n=5). All treatment protocols except control group were followed by topical eye drops composed of VIP at two hourly intervals for one week from 8 a.m. to 6 p.m. RESULTS VIP treated groups of rabbits with alkali burns were found to have better wound healing findings histo-pathologically when compared to those of control group who have received no treatment on day 30. No differences were observed between groups in respect to degree of polymorphonuclear leukocytes (PMNL) infiltration and degree of loss of amorphous substrate on day 15. However, PMNL infiltration and degree of loss of amorphous substrate were lower in Groups 2 and 3 when compared to that of control group on day 30 (P<0.05). CONCLUSION We have shown that VIP has positive effects on alkali induced corneal burns. VIP may inhibit PMNL migration to cornea through an immunomodulatory effect. Inhibition of PMNL migration might reduce the release of collagenases and this might prevent the extracellular amorphous substance loss. PMID:26949636

  5. Modulation of Corpus Striatal Neurochemistry by Astrocytes and Vasoactive Intestinal Peptide (VIP) in Parkinsonian Rats.

    PubMed

    Yelkenli, İbrahim Halil; Ulupinar, Emel; Korkmaz, Orhan Tansel; Şener, Erol; Kuş, Gökhan; Filiz, Zeynep; Tunçel, Neşe

    2016-06-01

    The neurotoxin 6-hydroxydopamine (6-OHDA) is widely used in animal models of Parkinson's disease. In various neurodegenerative diseases, astrocytes play direct, active, and critical roles in mediating neuronal survival and functions. Vasoactive intestinal peptide (VIP) has neurotrophic actions and modulates a number of astrocytic activities. In this study, the effects of VIP on the striatal neurochemistry were investigated in parkinsonian rats. Adult Sprague-Dawley rats were divided into sham-operated, unilaterally 6-OHDA-lesioned, and lesioned + VIP-administered (25 ng/kg i.p.) groups. VIP was first injected 1 h after the intrastriatal 6-OHDA microinjection and then every 2 days throughout 15 days. Extracellular striatal concentration of glutathione (GSH), gamma-aminobutyric acid (GABA), glutamate (GLU), and lactate were measured in microdialysates by high-performance liquid chromatography (HPLC). Quantification of GABA and activity dependent neuroprotective protein (ADNP)-expressing cells were determined by glutamic acid decarboxylase (GAD)/ADNP + glial fibrillary acidic protein (GFAP) double immunohistochemistry. Our results demonstrated that a 6-OHDA lesion significantly increased the density of astrocytes in the striatum and VIP treatment slightly reduced the gliosis. Extracellular concentration of GABA, GLU, and lactate levels did not change, but GSH level significantly increased in the striatum of parkinsonian rats. VIP treatment reduced GSH level comparable to sham-operated groups, but enhanced GABA and GLU levels. Our double labeling results showed that VIP primarily acts on neurons to increase ADNP and GAD expression for protection. These results suggest that, in the 6-OHDA-induced neurodegeneration model, astrocytes were possibly activated for forefront defensiveness by modulating striatal neurochemistry.

  6. Serum Levels of Vasoactive Intestinal Peptide as a Prognostic Marker in Early Arthritis

    PubMed Central

    Martínez, Carmen; Ortiz, Ana M.; Juarranz, Yasmina; Lamana, Amalia; Seoane, Iria V.; Leceta, Javier; García-Vicuña, Rosario

    2014-01-01

    Objective Suitable biomarkers are essential for the design of therapeutic strategies in personalized medicine. Vasoactive intestinal peptide (VIP) has demonstrated immunomodulatory properties in autoimmune murine and ex vivo human models. Our aim was to study serum levels of VIP during the follow-up of an early arthritis (EA) cohort and to analyze its value as a biomarker predicting severity and therapeutic requirements. Methods Data from 91 patients on an EA register were analyzed (76% rheumatoid arthritis (RA), 24% undifferentiated arthritis, 73% women, and median age 54 years; median disease duration at entry, 5.4 months). We collected per protocol sociodemographic, clinical, and therapeutic data. VIP levels were determined by enzyme immunoassay in sera harvested from the 91 patients (353 visits; 3.9 visit/patient) and from 100 healthy controls. VIP values below the 25th percentile of those assessed in healthy population were considered low. To determine the effect of independent variables on VIP levels, we performed a longitudinal multivariate analysis nested by patient and visit. A multivariate ordered logistic regression was modeled to determine the effect of low VIP serum levels on disease activity at the end of follow-up. Results VIP concentrations varied considerably across EA patients. Those fulfilling the criteria for RA had the lowest values in the whole sample, although no significant differences were observed compared with healthy donors. Disease activity, which was assessed using DAS28, inversely correlated with VIP levels. After a two-year follow-up, those patients with low baseline levels of VIP displayed higher disease activity and received more intensive treatment. Conclusion Patients who are unable to up-regulate VIP seem to have a worse clinical course despite receiving more intense treatment. Therefore, measurement of VIP levels may be suitable as a prognostic biomarker. PMID:24409325

  7. Corneal Endothelial Cell Integrity in Precut Human Donor Corneas Enhanced by Autocrine Vasoactive Intestinal Peptide

    PubMed Central

    Coll, Timothy; Gloria, Dante; Sprehe, Nicholas

    2017-01-01

    Purpose: To demonstrate that vasoactive intestinal peptide (VIP), a corneal endothelial (CE) cell autocrine factor, maintains the integrity of corneal endothelium in human donor corneoscleral explants precut for endothelial keratoplasty. Methods: Twelve paired human donor corneoscleral explants used as control versus VIP-treated explants (10 nM, 30 minutes, 37°C) were shipped (4°C) to the Lions Eye Institute for Transplantation and Research for precutting (Moria CBM-ALTK Keratome), shipped back to the laboratory, and cultured in ciliary neurotrophic factor (CNTF, 0.83 nM, 37°C, 24 hours). Trephined endothelial discs (8–8.5 mm) were analyzed for differentiation markers (N-cadherin, CNTF receptor α subunit [CNTFRα], and connexin 43) by Western blot after a quarter of the discs from 4 paired explants were cut away and stained with alizarin red S for microscopic damage analysis. Two additional paired explants (6 days in culture) were stained for panoramic view of central CE damage. Results: VIP treatment increased N-cadherin and CNTFRα levels (mean ± SEM) to 1.38 ± 0.11-fold (P = 0.003) and 1.46 ± 0.22-fold (P = 0.03) of paired controls, respectively, whereas CE cell CNTF responsiveness in upregulation of connexin 43 increased to 2.02 ± 0.5 (mean ± SEM)-fold of the controls (P = 0.04). CE damage decreased from (mean ± SEM) 10.0% ± 1.2% to 1.6% ± 0.3% (P < 0.0001) and 9.1% ± 1.1% to 2.4% ± 1.0% (P = 0.0006). After 6 days in culture, the damage in whole CE discs decreased from 20.0% (control) to 5.5% (VIP treated). Conclusions: VIP treatment before precut enhanced the preservation of corneal endothelium. PMID:28181929

  8. Roles of sphincter of Oddi motility and serum vasoactive intestinal peptide, gastrin and cholecystokinin octapeptide

    PubMed Central

    Zhang, Zhen-Hai; Qin, Cheng-Kun; Wu, Shuo-Dong; Xu, Jian; Cui, Xian-Ping; Wang, Zhi-Yi; Xian, Guo-Zhe

    2014-01-01

    AIM: To investigate roles of sphincter of Oddi (SO) motility played in pigment gallbladder stone formation in model of guinea pigs. METHODS: Thirty-four adult male Hartley guinea pigs were divided randomly into two groups: the control group and pigment stone group. The pigment stone group was divided into 4 subgroups with 6 guinea pigs each according to time of sacrifice, and were fed a pigment lithogenic diet and sacrificed after 3, 6, 9 and 12 wk. SO manometry and recording of myoelectric activity of the guinea pigs were obtained by multifunctional physiograph at each stage. Serum vasoactive intestinal peptide (VIP), gastrin and cholecystokinin octapeptide (CCK-8) were detected at each stage in the process of pigment gallbladder stone formation by enzyme-linked immunosorbent assay. RESULTS: The incidence of pigment gallstone formation was 0%, 0%, 16.7% and 66.7% in the 3-, 6-, 9- and 12-wk group, respectively. The frequency of myoelectric activity decreased in the 3-wk group. The amplitude of myoelectric activity had a tendency to decrease but not significantly. The frequency of the SO decreased significantly in the 9-wk group. The SO basal pressure and common bile duct pressure increased in the 12-wk group (25.19 ± 7.77 mmHg vs 40.56 ± 11.81 mmHg, 22.35 ± 7.60 mmHg vs 38.51 ± 11.57 mmHg, P < 0.05). Serum VIP was significantly elevated in the 6- and 12-wk groups and serum CCK-8 was decreased significantly in the 12-wk group. CONCLUSION: Pigment gallstone-causing diet may induce SO dysfunction. The tension of the SO increased. The disturbance in SO motility may play a role in pigment gallstone formation, and changes in serum VIP and CCK-8 may be important causes of SO dysfunction. PMID:24782626

  9. Newly identified PcToll4 regulates antimicrobial peptide expression in intestine of red swamp crayfish Procambarus clarkii.

    PubMed

    Huang, Ying; Li, Tingting; Jin, Min; Yin, Shaowu; Hui, Kai-Min; Ren, Qian

    2017-02-14

    Tolls or Toll-like receptors (TLRs) have an essential role in initiating innate immune responses against pathogens. In this study, a novel Toll gene, PcToll4, was first identified from the intestinal transcriptome of the freshwater crayfish, Procambarus clarkii. The PcToll4 cDNA is 4849bp long with a 3036bp open reading frame that encodes a 1011-amino acid protein. PcToll4 contains a signal peptide, 13 LRR domains, 3 LRR TYP domains, 2 LRR CT domains, an LRR NT domain, a transmembrane region, and a TIR domain. Quantitative RT-PCR analysis revealed that PcToll4 mRNA was detected in all tested tissues, and the expression of PcToll4 in the intestine was significantly upregulated after white spot syndrome virus (WSSV) challenge. Overexpression of PcToll4 in Drosophila Schneider 2 (S2) cells activates the antimicrobial peptides (AMPs) of Drosophila, including metchnikowin, drosomycin, attacin A, and shrimp Penaeidin-4. Results of RNA interference by siRNA also showed that PcToll4 regulates the expressions of 5 anti-lipopolysaccharide factors (ALFs) in the intestine of crayfish. Our findings suggest that PcToll4 is important for the innate immune responses of P. clarkii because this gene regulates the expressions of AMPs against WSSV.

  10. Reversible Opening of Intercellular Junctions of Intestinal Epithelial and Brain Endothelial Cells With Tight Junction Modulator Peptides.

    PubMed

    Bocsik, Alexandra; Walter, Fruzsina R; Gyebrovszki, Andrea; Fülöp, Lívia; Blasig, Ingolf; Dabrowski, Sebastian; Ötvös, Ferenc; Tóth, András; Rákhely, Gábor; Veszelka, Szilvia; Vastag, Monika; Szabó-Révész, Piroska; Deli, Mária A

    2016-02-01

    The intercellular junctions restrict the free passage of hydrophilic compounds through the paracellular clefts. Reversible opening of the tight junctions of biological barriers is investigated as one of the ways to increase drug delivery to the systemic circulation or the central nervous system. Six peptides, ADT-6, HAV-6, C-CPE, 7-mer (FDFWITP, PN-78), AT-1002, and PN-159, acting on different integral membrane and linker junctional proteins were tested on Caco-2 intestinal epithelial cell line and a coculture model of the blood-brain barrier. All peptides tested in nontoxic concentrations showed a reversible tight junctions modulating effect and were effective to open the paracellular pathway for the marker molecules fluorescein and albumin. The change in the structure of cell-cell junctions was verified by immunostaining for occludin, claudin-4,-5, ZO-1, β-catenin, and E-cadherin. Expression levels of occludin and claudins were measured in both models. We could demonstrate a selectivity of C-CPE, ADT-6, and HAV-6 peptides for epithelial cells and 7-mer and AT-1002 peptides for brain endothelial cells. PN-159 was the most effective modulator of junctional permeability in both models possibly acting via claudin-1 and -5. Our results indicate that these peptides can be effectively and selectively used as potential pharmaceutical excipients to improve drug delivery across biological barriers.

  11. Isolation and characterisation of a novel antibacterial peptide from a native swine intestinal tract-derived bacterium.

    PubMed

    Xin, Haiyun; Ji, Shengyue; Peng, Jiayin; Han, Peng; An, Xiaopeng; Wang, Shan; Cao, Binyun

    2017-02-27

    Antimicrobial peptides (AMPs) are highly associated with antipathogenic activity, without generating drug resistance in targeted bacteria. In this study, the existence of AMPs in the Tibetan swine, a China-native, cold-resistant and seldom-sick breed of pig, was investigated. A peptide secreted by a Tibetan swine intestinal tract-derived Bacillus strain was isolated using reversed-phase chromatography (RPC), ultrafiltration and reversed-phase high-performance liquid chromatography (RP-HPLC). The peptide was identified by mass spectrometry and was characterised for activity against Escherichia coli and Staphylococcus aureus. The 16-amino acid peptide (ASVVNKLTGGVAGLLK), named TP, had a molecular mass of 1568.919 Da and exhibited inhibitory activity against Gram-positive and Gram-negative bacteria [minimum inhibitory concentrations (MICs) of 2.5-5 µM and 10-20 µM for E. coli and S. aureus, respectively] as well as human MKN-45 and NB4 tumour cell lines [50% inhibitory concentration (IC50) = 4.686 µM and 11.479 µM, respectively]. TP also exhibited weak haemolytic activity. Furthermore, TP enhanced cell membrane permeability and K(+) outflow, bound with E. coli genomic DNA in vitro and inhibited E. coli growth. Thus, TP represents a strong candidate as an antibacterial peptide.

  12. Two weeks of moderate intensity continuous training, but not high intensity interval training increases insulin-stimulated intestinal glucose uptake.

    PubMed

    Motiani, Kumail Kumar; Savolainen, Anna M; Eskelinen, Jari-Joonas; Toivanen, Jussi; Ishizu, Tamiko; Yli-Karjanmaa, Minna; Virtanen, Kirsi A; Parkkola, Riitta; Kapanen, Jukka; Gronroos, Tove J; Haaparanta-Solin, Merja; Solin, Olof; Savisto, Nina; Ahotupa, Markku; Löyttyniemi, Eliisa; Knuuti, Juhani; Nuutila, Pirjo; Kalliokoski, Kari K; Hannukainen, Jarna C

    2017-02-09

    Similar to muscles, the intestine is also insulin resistant in obese subjects and subjects with impaired glucose tolerance. Exercise training improves muscle insulin sensitivity, but its effects on intestinal metabolism are not known. We studied the effects of high intensity interval training (HIIT) and moderate intensity continuous training (MICT) on intestinal glucose and free fatty acid uptake from circulation in humans. Twenty-eight healthy middle-aged sedentary men were randomized for two weeks of HIIT or MICT. Intestinal insulin-stimulated glucose uptake and fasting free fatty acid uptake from circulation were measured using positron emission tomography and [(18)F]FDG and [(18)F]FTHA. In addition, effects of HIIT and MICT on intestinal Glut2 and CD36 protein expression were studied in rats. Training improved aerobic capacity (p=0.001) and whole-body insulin sensitivity (p=0.04), but not differently between HIIT and MICT. Insulin-stimulated glucose uptake increased only after the MICT in the colon [HIIT=0%; MICT=37%] (p=0.02 for time*training) and tended to increase in the jejunum [HIIT=-4%; MICT=13%] (p=0.08 for time*training). Fasting free fatty acid uptake decreased in the duodenum in both groups [HIIT=-6%; MICT=-48%] (p=0.001 time) and tended to decrease in the colon in the MICT group [HIIT=0%; MICT=-38%] (p=0.08 for time*training). In rats, both training groups had higher Glut2 and CD36 expression compared to control animals. This study shows that already two weeks of MICT enhances insulin-stimulated glucose uptake while both training modes reduce fasting free fatty acid uptake in the intestine in healthy middle-aged men, providing an additional mechanism by which exercise training can improve whole body metabolism.

  13. Sustained glucagon-like peptide-2 infusion is required for intestinal adaptation, and cessation reverses increased cellularity in rats with intestinal failure

    PubMed Central

    Koopmann, Matthew C.; Chen, Xueyan; Holst, Jens J.

    2010-01-01

    Glucagon-like peptide-2 (GLP-2) is a nutrient-dependent, proglucagon-derived hormone that is a proposed treatment for human short bowel syndrome (SBS). The objective was to determine how the timing, duration, and cessation of GLP-2 administration affect intestinal adaptation and enterocyte kinetics in a rat model of human SBS that results in intestinal failure requiring total parenteral nutrition (TPN). Rats underwent 60% jejunoileal resection plus cecectomy and jugular vein cannulation and were maintained exclusively with TPN for 18 days in these treatments: TPN control (no GLP-2); sustained GLP-2 (1–18 days); early GLP-2 (1–7 days, killed at 7 or 18 days); and delayed GLP-2 (12–18 days). Body weight gain was similar across groups, and plasma bioactive GLP-2 was significantly increased with coinfusion of GLP-2 (100 μg·kg−1·day−1) with TPN. GLP-2-treated rats showed significant increases in duodenum and jejunum mucosal dry mass, protein, DNA, and sucrase activity compared with TPN control. The increased jejunum cellularity reflected significantly decreased apoptosis and increased crypt mitosis and crypt fission due to GLP-2. When GLP-2 infusion stopped at 7 days, these effects were reversed at 18 days. Sustained GLP-2 infusion significantly increased duodenum length and decreased 18-day mortality to 0% from 37.5% deaths in TPN control (P = 0.08). Colon proglucagon expression quantified by real-time RT-qPCR was increased in TPN controls and attenuated by GLP-2 infusion; jejunal expression of the GLP-2 receptor did not differ among groups. In summary, early, sustained GLP-2 infusion reduces mortality, induces crypt fission, and is required for intestinal adaptation, whereas cessation of GLP-2 reverses gains in mucosal cellularity in a rat model of intestinal failure. PMID:20864657

  14. Region-Dependent Role of Cell-Penetrating Peptides in Insulin Absorption Across the Rat Small Intestinal Membrane.

    PubMed

    Khafagy, El-Sayed; Iwamae, Ruisha; Kamei, Noriyasu; Takeda-Morishita, Mariko

    2015-11-01

    We have reported that the cell-penetrating peptide (CPP) penetratin acts as a potential absorption enhancer in oral insulin delivery systems and that this action occurs through noncovalent intermolecular interactions. However, the region-dependent role of CPPs in intestinal insulin absorption has not been clarified. To identify the intestinal region where CPPs have the most effect in increasing insulin absorption, the region-dependent action of penetratin was investigated using in situ closed intestinal loops in rats. The order of the insulin area under the insulin concentration-time curve (AUC) increase effect by L-penetratin was ileum > jejunum > duodenum > colon. By contrast, the AUC order after coadministration of insulin with D-penetratin was colon > duodenum ≥ jejunum and ileum. We also compared the effects of the L- and D-forms of penetratin, R8, and PenetraMax on ileal insulin absorption. Along with the CPPs used in this study, L- and D-PenetraMax produced the largest insulin AUCs. An absorption study using ilea pretreated with CPPs showed that PenetraMax had no irreversible effect on the intestinal epithelial membrane. The degradation of insulin in the presence of CPPs was assessed in rat intestinal enzymatic fluid. The half-life (t 1/2) of insulin increased from 14.5 to 23.7 and 184.7 min in the presence of L- and D-PenetraMax, respectively. These enzymatic degradation-resistant effects might contribute partly to the increased ileal absorption of insulin induced by D-PenetraMax. In conclusion, this study demonstrated that the ability of the L- and D-forms of penetratin to increase intestinal insulin absorption was maximal in the ileum and the colon, respectively, and that D-PenetraMax is a powerful but transient enhancer of oral insulin absorption.

  15. Glucagon-like peptide 1 (1–37) converts intestinal epithelial cells into insulin-producing cells

    PubMed Central

    Suzuki, Atsushi; Nakauchi, Hiromitsu; Taniguchi, Hideki

    2003-01-01

    Glucagon-like peptide (GLP) 1 is produced through posttranslational processing of proglucagon and acts as a regulator of various homeostatic events. Among its analogs, however, the function of GLP-1-(1–37), synthesized in small amounts in the pancreas, has been unclear. Here, we find that GLP-1-(1–37) induces insulin production in developing and, to a lesser extent, adult intestinal epithelial cells in vitro and in vivo, a process mediated by up-regulation of the Notch-related gene ngn3 and its downstream targets, which are involved in pancreatic endocrine differentiation. These cells became responsive to glucose challenge in vitro and reverse insulin-dependent diabetes after implantation into diabetic mice. Our findings suggest that efficient induction of insulin production in intestinal epithelial cells by GLP-1-(1–37) could represent a new therapeutic approach to diabetes mellitus. PMID:12702762

  16. Epidermal growth factor-stimulated intestinal epithelial cell migration requires Src family kinase-dependent p38 MAPK signaling.

    PubMed

    Frey, Mark R; Golovin, Anastasia; Polk, D Brent

    2004-10-22

    Members of the epidermal growth factor (EGF) family of ligands and their receptors regulate migration and growth of intestinal epithelial cells. However, our understanding of the signal transduction pathways determining these responses is incomplete. In this study we tested the hypothesis that p38 is required for EGF-stimulated intestinal epithelial monolayer restitution. EGF-stimulated migration in a wound closure model required continuous presence of ligand for several hours for maximal response, suggesting a requirement for sustained signal transduction pathway activation. In this regard, prolonged exposure of cells to EGF activated p38 for up to 5 h. Furthermore genetic or pharmacological blockade of p38 signaling inhibited the ability of EGF to accelerate wound closure. Interestingly p38 inhibition was associated with increased EGF-stimulated ERK1/ERK2 phosphorylation and cell proliferation, suggesting that p38 regulates the balance of proliferation/migration signaling in response to EGF receptor activity. Activation of p38 in intestinal epithelial cells through EGF receptor was abolished by blockade of Src family tyrosine kinase signaling but not inhibition of phosphatidylinositol 3-kinase or protein kinase C. Taken together, these data suggest that Src family kinase-dependent p38 activation is a key component of a signaling switch routing EGF-stimulated responses to epithelial cell migration/restitution rather than proliferation during wound closure.

  17. Calcitonin gene-related peptide (CGRP) stimulates purkinje cell dendrite growth in culture.

    PubMed

    D'Antoni, Simona; Zambusi, Laura; Codazzi, Franca; Zacchetti, Daniele; Grohovaz, Fabio; Provini, Luciano; Catania, Maria Vincenza; Morara, Stefano

    2010-12-01

    Previous reports described the transient expression during development of Calcitonin Gene-Related Peptide (CGRP) in rodent cerebellar climbing fibers and CGRP receptor in astrocytes. Here, mixed cerebellar cultures were used to analyze the effects of CGRP on Purkinje cells growth. Our results show that CGRP stimulated Purkinje cell dendrite growth under cell culture conditions mimicking Purkinje cell development in vivo. The stimulation was not blocked by CGRP8-37, a specific antagonist, suggesting the activation of other related receptors. CGRP did not affect survival of Purkinje cells, granule cells or astrocytes. The selective expression of Receptor Component Protein (RCP) (a component of CGRP receptor family) in astrocytes points to a role of these cells as mediators of CGRP effect. Finally, in pure cerebellar astrocyte cultures CGRP induced a transient morphological differentiation from flat, polygonal to stellate form. It is concluded that CGRP influences Purkinje cell dendrite growth in vitro, most likely through the involvement of astrocytes.

  18. Mass balance approaches for estimating the intestinal absorption and metabolism of peptides and analogues: theoretical development and applications

    NASA Technical Reports Server (NTRS)

    Sinko, P. J.; Leesman, G. D.; Amidon, G. L.

    1993-01-01

    A theoretical analysis for estimating the extent of intestinal peptide and peptide analogue absorption was developed on the basis of a mass balance approach that incorporates convection, permeability, and reaction. The macroscopic mass balance analysis (MMBA) was extended to include chemical and enzymatic degradation. A microscopic mass balance analysis, a numerical approach, was also developed and the results compared to the MMBA. The mass balance equations for the fraction of a drug absorbed and reacted in the tube were derived from the general steady state mass balance in a tube: [formula: see text] where M is mass, z is the length of the tube, R is the tube radius, Pw is the intestinal wall permeability, kr is the reaction rate constant, C is the concentration of drug in the volume element over which the mass balance is taken, VL is the volume of the tube, and vz is the axial velocity of drug. The theory was first applied to the oral absorption of two tripeptide analogues, cefaclor (CCL) and cefatrizine (CZN), which degrade and dimerize in the intestine. Simulations using the mass balance equations, the experimental absorption parameters, and the literature stability rate constants yielded a mean estimated extent of CCL (250-mg dose) and CZN (1000-mg dose) absorption of 89 and 51%, respectively, which was similar to the mean extent of absorption reported in humans (90 and 50%). It was proposed previously that 15% of the CCL dose spontaneously degraded systematically; however, our simulations suggest that significant CCL degradation occurs (8 to 17%) presystemically in the intestinal lumen.(ABSTRACT TRUNCATED AT 250 WORDS).

  19. Stimulation of butyrate production in the large intestine of weaning piglets by dietary fructooligosaccharides and its influence on the histological variables of the large intestinal mucosa.

    PubMed

    Tsukahara, Takamitsu; Iwasaki, Yoshie; Nakayama, Keizo; Ushida, Kazunari

    2003-12-01

    Fructooligosaccharides (FOS) reach the large intestine and are fermented into short-chain fatty acids (SCFA), lactate, and carbon dioxide. As the major energy source for the epithelial cells of the large intestine, n-butyrate stimulates the proliferation of cells as well as mineral and water absorption from the lumen. We examined the effect of dietary FOS supplementation on luminal SCFA production and its influence on the morphometrical variables of mucosa of the large intestine in commercially available pigs. Six weaning piglets were used. After 7 d of adaptation, three pigs were given a test diet containing FOS (10%) ad libitum for 10 d. The other three remained on the basal diet and were used as controls. At the end of the experiment, their large intestines were removed, and the cecum, gyri centripetales, gyri centrifugales, and rectum were separated. The contents of each portion were collected and measured for SCFA concentration, pH, and moisture. A micrometer was used to measure the crypt depth. The numbers of epithelial and mitotic cells in the crypt columns were also counted. The concentration of SCFA was significantly higher in piglets fed FOS than in the controls. The concentration of n-butyrate was markedly stimulated by FOS. The number of epithelial. mitotic, and mucin-containing cells was higher in piglets fed FOS than in the controls. Accordingly, the crypt depth was larger in the FOS-fed piglets. The luminal n-butyrate concentration showed a significantly positive correlation with the crypt depth and the number of epithelial, mitotic, and mucin-containing cells.

  20. Activation of CFTR trafficking and gating by vasoactive intestinal peptide in human bronchial epithelial cells.

    PubMed

    Qu, Fei; Liu, Hui-Jun; Xiang, Yang; Tan, Yu-Rong; Liu, Chi; Zhu, Xiao-Lin; Qin, Xiao-Qun

    2011-03-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is an apical membrane chloride channel critical to the regulation of fluid, chloride, and bicarbonate transport in epithelia and other cell types. The most common cause of cystic fibrosis (CF) is the abnormal trafficking of CFTR mutants. Therefore, understanding the cellular machineries that transit CFTR from the endoplasmic reticulum to the cell surface is important. Vasoactive intestinal polypeptide (VIP) plays an important role in CFTR-dependent chloride transport. The present study was designed to observe the affection of VIP on the trafficking of CFTR, and channel gating in human bronchial epithelium cells (HBEC). Confocal microscopy revealed CFTR immunofluorescence extending from the apical membrane deeply into the cell cytoplasm. After VIP treatment, apical extension of CFTR immunofluorescence into the cell was reduced and the peak intensity of CFTR fluorescence shifted towards the apical membrane. Western blot showed VIP increased cell surface and total CFTR. Compared with the augmented level of total CFTR, the surface CFTR increased more markedly. Immunoprecipitation founded that the mature form of CFTR had a marked increase in HBEC treated with VIP. VIP led to a threefold increase in Cl(-) efflux in HBEC. Glibenclamide-sensitive and DIDS-insensitive CFTR Cl(-) currents were consistently observed after stimulation with VIP (10(-8) mol/L). The augmentation of CFTR Cl(-) currents enhanced by VIP (10(-8) mol/L) was reversed, at least in part, by the protein kinase A (PKA) inhibitor, H-89 and the protein kinase C (PKC) inhibitor, H-7, suggesting PKA and PKC participate in the VIP-promoted CFTR Cl(-) currents.

  1. CD8+ T cells of chronic HCV-infected patients express multiple negative immune checkpoints following stimulation with HCV peptides.

    PubMed

    Barathan, Muttiah; Mohamed, Rosmawati; Vadivelu, Jamuna; Chang, Li Yen; Vignesh, Ramachandran; Krishnan, Jayalakshmi; Sigamani, Panneer; Saeidi, Alireza; Ram, M Ravishankar; Velu, Vijayakumar; Larsson, Marie; Shankar, Esaki M

    2017-03-01

    Hepatitis C virus (HCV)-specific CD4+ and CD8+ T cells are key to successful viral clearance in HCV disease. Accumulation of exhausted HCV-specific T cells during chronic infection results in considerable loss of protective functional immune responses. The role of T-cell exhaustion in chronic HCV disease remains poorly understood. Here, we studied the frequency of HCV peptide-stimulated T cells expressing negative immune checkpoints (PD-1, CTLA-4, TRAIL, TIM-3 and BTLA) by flow cytometry, and measured the levels of Th1/Th2/Th17 cytokines secreted by T cells by a commercial Multi-Analyte ELISArray™ following in vitro stimulation of T cells using HCV peptides and phytohemagglutinin (PHA). HCV peptide-stimulated CD4+ and CD8+ T cells of chronic HCV (CHC) patients showed significant increase of CTLA-4. Furthermore, HCV peptide-stimulated CD4+ T cells of CHC patients also displayed relatively higher levels of PD-1 and TRAIL, whereas TIM-3 was up-regulated on HCV peptide-stimulated CD8+ T cells. Whereas the levels of IL-10 and TGF-β1 were significantly increased, the levels of pro-inflammatory cytokines IL-2, TNF-α, IL-17A and IL-6 were markedly decreased in the T cell cultures of CHC patients. Chronic HCV infection results in functional exhaustion of CD4+ and CD8+ T cells likely contributing to viral persistence.

  2. Distinct Firing Properties of Vasoactive Intestinal Peptide-Expressing Neurons in the Suprachiasmatic Nucleus

    PubMed Central

    Hermanstyne, Tracey O.; Simms, Carrie L.; Carrasquillo, Yarimar; Herzog, Erik D.; Nerbonne, Jeanne M.

    2016-01-01

    The suprachiasmatic nucleus (SCN) regulates daily rhythms in physiology and behavior. Previous studies suggest a critical role for neurons expressing vasoactive intestinal peptide (VIP) in coordinating rhythmicity and synchronization in the SCN. Here we examined the firing properties of VIP-expressing SCN neurons in acute brain slices. Active and passive membrane properties were measured in VIP and in non-VIP neurons during the day and at night. Current-clamp recordings revealed that both VIP and non-VIP neurons were spontaneously active, with higher firing rates during the day than at night. Average firing frequencies, however, were higher in VIP neurons (3.1 ± 0.2 Hz, day and 2.4 ± 0.2 Hz, night) than in non-VIP neurons (1.8 ± 0.2 Hz, day and 0.9 ± 0.2 Hz, night), both day and night. The waveforms of individual action potentials in VIP and non-VIP neurons were also distinct. Action potential durations (APD50) were shorter in VIP neurons (3.6 ± 0.1 ms, day and 2.9 ± 0.1 ms, night) than in non-VIP neurons (4.4 ± 0.3 ms, day and 3.5 ± 0.2 ms, night) throughout the light-dark cycle. In addition, after hyper polarization (AHP) amplitudes were larger in VIP neurons (21 ± 0.8 mV, day and 24.9 ± 0.9 mV, night) than in non-VIP neurons (17.2 ± 1.1 mV, day and 20.5 ± 1.2 mV, night) during the day and at night. Furthermore, significant day/night differences were observed in APD50 and AHP amplitudes in both VIP and non-VIP SCN neurons, consistent with rhythmic changes in ionic conductances that contribute to shaping the firing properties of both cell types. The higher day and night firing rates of VIP neurons likely contribute to synchronizing electrical activity in the SCN. PMID:26712166

  3. Effects of the mucoadhesive polymer polycarbophil on the intestinal absorption of a peptide drug in the rat.

    PubMed

    Lehr, C M; Bouwstra, J A; Kok, W; De Boer, A G; Tukker, J J; Verhoef, J C; Breimer, D D; Junginger, H E

    1992-05-01

    The absorption across rat intestinal tissue of the model peptide drug 9-desglycinamide, 8-arginine vasopressin from bioadhesive formulations was studied in-vitro, in a chronically isolated internal loop in-situ and after intraduodenal administration in-vivo. A controlled-release bioadhesive drug delivery system was tested, consisting of microspheres of poly(2-hydroxyethyl methacrylate) with a mucoadhesive Polycarbophil-coating, as well as fast-release formulation consisting of an aqueous solution of the peptide in a suspension of Polycarbophil particles. Using the controlled-release system, a slight improvement of peptide absorption was found in-vitro in comparison with a non-adhesive control system, but not in-situ or in-vivo. In contrast, bioavailability was significantly increased in all three models from the Polycarbophil suspension in comparison with a solution of the drug in saline. The effect appeared to be dose-dependent, indicative of intrinsic penetration-enhancing properties of the mucoadhesive polymer. A prolongation of the absorption phase in-vitro and in the chronically isolated loop in-situ suggested that the polymer was able to protect the peptide from proteolytic degradation. This could be confirmed by degradation studies in-vitro. The duration of the penetration enhancing/enzyme inhibiting effect was diminished with increasing complexity of the test model, in the same way as was previously found for the bioadhesive effect. This interrelationship suggests that the observed improvement in peptide absorption and the mucoadhesive properties of this polymer are associated. The development of a fast-release oral dosage form for peptide drugs on the basis of Polycarbophil appears to be possible.

  4. Transcobalamin derived from bovine milk stimulates apical uptake of vitamin B12 into human intestinal epithelial cells.

    PubMed

    Hine, Brad; Boggs, Irina; Green, Ralph; Miller, Joshua W; Hovey, Russell C; Humphrey, Rex; Wheeler, Thomas T

    2014-11-01

    Intestinal uptake of vitamin B12 (hereafter B12) is impaired in a significant proportion of the human population. This impairment is due to inherited or acquired defects in the expression or function of proteins involved in the binding of diet-derived B12 and its uptake into intestinal cells. Bovine milk is an abundant source of bioavailable B12 wherein it is complexed with transcobalamin. In humans, transcobalamin functions primarily as a circulatory protein, which binds B12 following its absorption and delivers it to peripheral tissues via its cognate receptor, CD320. In the current study, the transcobalamin-B12 complex was purified from cows' milk and its ability to stimulate uptake of B12 into cultured bovine, mouse and human cell lines was assessed. Bovine milk-derived transcobalamin-B12 complex was absorbed by all cell types tested, suggesting that the uptake mechanism is conserved across species. Furthermore, the complex stimulated the uptake of B12 via the apical surface of differentiated Caco-2 human intestinal epithelial cells. These findings suggest the presence of an alternative transcobalamin-mediated uptake pathway for B12 in the human intestine other than that mediated by the gastric glycoprotein, intrinsic factor. Our findings highlight the potential for transcobalamin-B12 complex derived from bovine milk to be used as a natural bioavailable alternative to orally administered free B12 to overcome B12 malabsorption.

  5. Protein from intestinal Eimeria protozoan stimulates IL-12 release from dendritic cells, exhibits antitumor properties in vivo and is correlated with low intestinal tumorigenicity.

    PubMed

    Rosenberg, Barnett; Juckett, David A; Aylsworth, Charles F; Dimitrov, Nikolay V; Ho, Siu-Cheong; Judge, John W; Kessel, Sarah; Quensen, Janet; Wong, Kwai-Pheng Ho; Zlatkin, Igor; Zlatkin, Tanya

    2005-05-01

    The small intestine (SI) of vertebrates exhibits low tumorigenesis and rarely supports metastatic growth from distant tumors. Many theories have been proposed to address this phenomenon, but none has been consistently supported. One candidate mechanism is that the vast immunologic compartment of the SI provides a heightened level of tumor immunosurveillance. Consistent with this, we have identified a molecule of low abundance from bovine SI that has the hallmarks of a potent immunostimulant and may be associated with the natural suppression of cancer in the intestinal tract. The protein originates from an endemic gut protozoan, Eimeria spp., and is homologous to the antigen 3-1E previously isolated from the avian apicomplexan E. acervulina. We show here that it is a very potent stimulator of IL-12 release from dendritic cells, upregulates inflammatory modulators in vivo (IL-12, MCP-1, IL-6, TNF-alpha and INF-gamma) and has antitumor properties in mice. In addition, it is synergistic in vitro with anti-CD40 antibody, IFN-gamma, IL-4 and GM-CSF; is active across species barriers in vivo; and has no observable toxicity. Based on these activities, we speculate that it is an inducer of protozoan-targeted innate immunity, which may explain its potential benefit to the intestinal tract and potency as an agent in cancer immunotherapy.

  6. Enhanced visualization of small peptides absorbed in rat small intestine by phytic-acid-aided matrix-assisted laser desorption/ionization-imaging mass spectrometry.

    PubMed

    Hong, Seong-Min; Tanaka, Mitsuru; Yoshii, Saori; Mine, Yoshinori; Matsui, Toshiro

    2013-11-05

    Enhanced visualization of small peptides absorbed through a rat intestinal membrane was achieved by matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-IMS) with the aid of phytic acid as a matrix additive. Penetrants through intestinal peptide transporter 1, i.e., glycyl-sarcosine (Gly-Sar, 147.1 m/z) and antihypertensive dipeptide, Val-Tyr (281.2 m/z), were chosen for MALDI-IMS. The signal-to-noise (S/N) ratios of dipeptides Gly-Sar and Val-Tyr were seen to increase by 2.4- and 8.0-fold, respectively, when using a 2',4',6'-trihydroxyacetophenone (THAP) matrix containing 5.0 mM phytic acid, instead of the THAP matrix alone. Owing to the phytic-acid-aided MALDI-IMS method, Gly-Sar and Val-Tyr absorbed in the rat intestinal membrane were successfully visualized. The proposed imaging method also provided useful information on intestinal peptide absorption; to some extent, Val-Tyr was rapidly hydrolyzed to Tyr by peptidases located at the intestinal microvillus during the absorption process. In conclusion, the strongly acidic additive, phytic acid, is beneficial for enhancing the visualization of small peptides using MALDI-IMS, owing to the suppression of ionization-interfering salts in the tissue.

  7. Intestinal adaptation following resection.

    PubMed

    Tappenden, Kelly A

    2014-05-01

    Intestinal adaptation is a natural compensatory process that occurs following extensive intestinal resection, whereby structural and functional changes in the intestine improve nutrient and fluid absorption in the remnant bowel. In animal studies, postresection structural adaptations include bowel lengthening and thickening and increases in villus height and crypt depth. Functional changes include increased nutrient transporter expression, accelerated crypt cell differentiation, and slowed transit time. In adult humans, data regarding adaptive changes are sparse, and the mechanisms underlying intestinal adaptation remain to be fully elucidated. Several factors influence the degree of intestinal adaptation that occurs post resection, including site and extent of resection, luminal stimulation with enteral nutrients, and intestinotrophic factors. Two intestinotrophic growth factors, the glucagon-like peptide 2 analog teduglutide and recombinant growth hormone (somatropin), are now approved for clinical use in patients with short bowel syndrome (SBS). Both agents enhance fluid absorption and decrease requirements for parenteral nutrition (PN) and/or intravenous fluid. Intestinal adaptation has been thought to be limited to the first 1-2 years following resection in humans. However, recent data suggest that a significant proportion of adult patients with SBS can achieve enteral autonomy, even after many years of PN dependence, particularly with trophic stimulation.

  8. Apelin stimulates both cholecystokinin and glucagon-like peptide 1 secretions in vitro and in vivo in rodents.

    PubMed

    Wattez, Jean-Sébastien; Ravallec, Rozenn; Cudennec, Benoit; Knauf, Claude; Dhulster, Pascal; Valet, Philippe; Breton, Christophe; Vieau, Didier; Lesage, Jean

    2013-10-01

    Apelin is an enteric peptide that exerts several digestive functions such as stimulation of cell proliferation and cholecystokinin (CCK) secretion. We investigated using murine enteroendocrine cell line (STC-1) and rats if apelin-13 stimulates both CCK and glucagon-like peptide 1 (GLP-1) secretions. We demonstrated that, in vitro and in vivo, apelin-13 increases the release of these two hormones in a dose-dependent manner. Present data suggest that apelin may modulate digestive functions, food intake behavior and glucose homoeostasis via apelin-induced release of enteric CCK but also through a new incretin-releasing activity on enteric GLP-1.

  9. Modulatory Effects of Vasoactive Intestinal Peptide on Intestinal Mucosal Immunity and Microbial Community of Weaned Piglets Challenged by an Enterotoxigenic Escherichia coli (K88)

    PubMed Central

    Xu, Chunlan; Wang, Youming; Sun, Rui; Qiao, Xiangjin; Shang, Xiaoya; Niu, Weining

    2014-01-01

    Toll-like receptors (TLRs) recognize microbial pathogens and trigger immune response, but their regulation by neuropeptide-vasoactive intestinal peptide (VIP) in weaned piglets infected by enterotoxigenic Escherichia coli (ETEC) K88 remains unexplored. Therefore, the study was conducted to investigate its role using a model of early weaned piglets infected by ETEC K88. Male Duroc×Landrace×Yorkshire piglets (n = 24) were randomly divided into control, ETEC K88, VIP, and ETEC K88+VIP groups. On the first three days, ETEC K88 and ETEC K88+VIP groups were orally administrated with ETEC K88, other two groups were given sterile medium. Then each piglet from VIP and ETEC K88+VIP group received 10 nmol VIP intraperitoneally (i.p.) once daily, on day four and six. On the seventh day, the piglets were sacrificed. The results indicated that administration of VIP improved the growth performance, reduced diarrhea incidence of ETEC K88 challenged pigs, and mitigated the histopathological changes of intestine. Serum levels of IL-2, IL-6, IL-12p40, IFN-γ and TNF-α in the ETEC K88+ VIP group were significantly reduced compared with those in the ETEC group. VIP significantly increased IL-4, IL-10, TGF-β and S-IgA production compared with the ETEC K88 group. Besides, VIP could inhibit the expression of TLR2, TLR4, MyD88, NF-κB p65 and the phosphorylation of IκB-α, p-ERK, p-JNK, and p-38 induced by ETEC K88. Moreover, VIP could upregulate the expression of occludin in the ileum mucosa compared with the ETEC K88 group. Colon and caecum content bacterial richness and diversity were lower for pigs in the ETEC group than the unchallenged groups. These results demonstrate that VIP is beneficial for the maturation of the intestinal mucosal immune system and elicited local immunomodulatory activities. The TLR2/4-MyD88 mediated NF-κB and MAPK signaling pathway may be critical to the mechanism underlying the modulatory effect of VIP on intestinal mucosal immune function and

  10. Hochuekkito, a Kampo (Traditional Japanese Herbal) Medicine, and its Polysaccharide Portion Stimulate G-CSF Secretion from Intestinal Epithelial Cells.

    PubMed

    Matsumoto, Tsukasa; Moriya, Michiyo; Kiyohara, Hiroaki; Tabuchi, Yoshiaki; Yamada, Haruki

    2010-09-01

    Kampo (traditional Japanese herbal) medicines are taken orally due to which the gastric mucosal immune system may act as one of the major targets for the expression of pharmacological activity. The inner surface of the intestinal tract possesses a large area of mucosal membranes, and the intestinal epithelial cells sit at the interface between a lumen and a lymphocyte-rich lamina propria. The cross talk that occurs between these compartments serves to maintain intestinal homeostasis, and the cytokine network plays an important role in the cross talk. In this study, the effect of Hochuekkito (HET), one of Kampo medicines, on cytokine secretion of intestinal epithelial cells was investigated. When murine normal colonic epithelial cell-line MCE301 cells were stimulated with HET, the contents of granulocyte colony-stimulating factor (G-CSF) in the conditioned medium were significantly increased in dose- and time-dependent manners. The enhanced G-CSF gene transcription in MCE301 cells by the stimulation of HET was observed by RT-PCR. The enhanced G-CSF secretion by HET was also observed in C3H/HeJ mice-derived primary cultured colonic epithelial cells. When the HET was fractionated, only the polysaccharide fraction (F-5) enhanced the G-CSF secretion of MCE301 cells, and the activity of F-5 lost after the treatment of periodate that can degrade the carbohydrate moiety. These results suggest that HET enhances secretion of G-CSF from colonic epithelial cells and the polysaccharide is one of the active ingredients of HET. The enhanced G-CSF secretion by HET may partly contribute to the clinically observed various pharmacological activities of HET including immunomodulating activity.

  11. Glugacon-like peptide-2: broad receptor expression, limited therapeutic effect on intestinal inflammation and novel role in liver regeneration.

    PubMed

    El-Jamal, Noura; Erdual, Edmone; Neunlist, Michel; Koriche, Dine; Dubuquoy, Caroline; Maggiotto, Francois; Chevalier, Julien; Berrebi, Dominique; Dubuquoy, Laurent; Boulanger, Eric; Cortot, Antoine; Desreumaux, Pierre

    2014-08-01

    The glucagon-like peptide 2 (GLP-2) is an intestinotrophic hormone with growth promoting and anti-inflammatory actions. However, the full biological functions of GLP-2 and the localization of its receptor (GLP-2R) remain controversial. Among cell lines tested, the expression of GLP-2R transcript was detected in human colonic myofibroblasts (CCD-18Co) and in primary culture of rat enteric nervous system but not in intestinal epithelial cell lines, lymphocytes, monocytes, or endothelial cells. Surprisingly, GLP-2R was expressed in murine (GLUTag), but not human (NCI-H716) enteroendocrine cells. The screening of GLP-2R mRNA in mice organs revealed an increasing gradient of GLP-2R toward the distal gut. An unexpected expression was detected in the mesenteric fat, mesenteric lymph nodes, bladder, spleen, and liver, particularly in hepatocytes. In two mice models of trinitrobenzene sulfonic acid (TNBS)- and dextran sulfate sodium (DSS)-induced colitis, the colonic expression of GLP-2R mRNA was decreased by 60% compared with control mice. Also, GLP-2R mRNA was significantly downregulated in intestinal tissues of inflammatory bowel disease patients. Therapeutically, GLP-2 showed a weak restorative effect on intestinal inflammation during TNBS-induced colitis as assessed by macroscopic score and inflammatory markers. Finally, GLP-2 treatment accelerated mouse liver regeneration following partial hepatectomy as assessed by histological and molecular analyses. In conclusion, the limited therapeutic effect of GLP-2 on colonic inflammation dampens its utility in the management of severe inflammatory intestinal disorders. However, the role of GLP-2 in liver regeneration is a novelty that might introduce GLP-2 into the management of liver diseases and emphasizes on the importance of elucidating other extraintestinal functions of GLP-2.

  12. A peptide from Porphyra yezoensis stimulates the proliferation of IEC-6 cells by activating the insulin-like growth factor I receptor signaling pathway.

    PubMed

    Lee, Min-Kyeong; Kim, In-Hye; Choi, Youn-Hee; Nam, Taek-Jeong

    2015-02-01

    Porphyra yezoensis (P. yezoensis) is the most noteworthy red alga and is mainly consumed in China, Japan and Korea. In the present study, the effects of a P. yezoensis peptide (PY‑PE) on cell proliferation and the associated signaling pathways were examined in IEC‑6 rat intestinal epithelial cells. First, the MTS assay showed that PY‑PE induced cell proliferation in a dose‑dependent manner. Subsequently, the mechanism behind the proliferative activity induced by PY‑PE was determined. The insulin‑like growth factor‑I receptor (IGF‑IR) signaling pathway was the main focus as it plays an important role in the regulation of cell growth and proliferation. PY‑PE increased the protein and mRNA expression of IGF‑IR, insulin receptor substrate‑1, Shc and PY‑99. In addition, PY‑PE stimulated extracellular signal‑regulated kinase phosphorylation and phosphatidylinositol 3‑kinase/Akt activation but inhibited p38 and c‑Jun N‑terminal kinase phosphorylation. Furthermore, PY‑PE treatment increased protein and mRNA expression levels of activator protein‑1, which regulates cell proliferation and survival, in the nuclear fraction. These results have significant implications for understanding the role of cell proliferation signaling pathways in intestinal epithelial cells.

  13. Mating and sex peptide stimulate the accumulation of yolk in oocytes of Drosophila melanogaster.

    PubMed

    Soller, M; Bownes, M; Kubli, E

    1997-02-01

    Mating elicits two reactions in many insect females: egg deposition is increased and receptivity to males is reduced. Central to the control of receptivity and oviposition in Drosophila melanogaster is the sex peptide (SP), a 36-amino-acid peptide sex pheromone synthesized in the male accessory glands and transferred to the female during copulation. To identify regulatory mechanisms involved in the maintenance of the oviposition response, we have compared the effects of mating and SP application with respect to oogenesis. The distribution of the various stages of oogenesis in the ovary, yolk protein (YP) synthesis by the fat body, as well as YP content, uptake and synthesis by the ovary were investigated. Transcripts of the yolk protein genes (yp) were quantified by Northern blotting. Based on our results, we conclude that mating and SP injection into virgin females stimulate yp gene transcription in the fat body only moderately above the background level. However, uptake into the ovary and transcription of the yp genes in the ovary is strongly enhanced after either mating or SP injection. These data are supported by the finding that the abundance of the vitellogenic stage 10 oocytes is also increased. In contrast, early vitellogenic stages 8 and 9 of oogenesis are present in the same numbers in virgin, mated, and SP-injected females, which suggests a control point at about stage 9 determining vitellogenic oocyte progression. The finding that SP can elicit equally all changes observed after copulation suggests that in the sexually mature female it is the major component controlling and stimulating oogenesis after mating.

  14. Characteristics of transmural potential changes associated with the proton-peptide co-transport in toad small intestine.

    PubMed

    Abe, M; Hoshi, T; Tajima, A

    1987-12-01

    1. Ionic dependence and kinetic properties of the peptide-evoked potentials across everted toad intestine were investigated with eighteen dipeptides and four tripeptides. All peptides evoked saturable increases in the mucosal negativity regardless of the presence of Na+. 2. The peptide-evoked potentials recorded in the absence of Na+ were sensitive to external pH (pHo); lowering pHo from 7.4 to 6.5 and 5.5 caused stepwise increases in their amplitude. 3. Loading epithelial cells with 9-aminoacridine or acetate caused a significant increase or decrease in amplitude of the Gly-Gly-evoked potential, suggesting intracellular alkalinization or acidification also has a great influence on the peptide-evoked potential. 4. Kinetically, Na+-independent peptide-evoked potentials conformed to simple Michaelis-Menten kinetics, and lowering pHo caused a decrease of the half-saturation concentration (Kt) for Gly-Gly without changing the maximum potential difference increase. Similar affinity-type kinetic effect was also seen for Gly-Gly influx. 5. Simultaneous measurements of Gly-Gly-induced increase in short-circuit current and Gly-Gly influx revealed that the coupling ratio of H+ and Gly-Gly flows was 1.78 +/- 0.12, suggesting the stoichiometry of the H+-peptide co-transport being 2:1. 6. Kinetic analyses of the peptide-evoked potentials indicated that all glycyl-dipeptides tested (Gly-Gly, Gly-Pro, Gly-Sar, Gly-Leu, Gly-Phe) and other dipeptides (Ala-Ala, Ala-Phe, Phe-Ala) shared a common carrier. Gly-Gly-Gly and Ala-Ala-Ala were also found to share the same carrier, while Phe-Phe, Leu-Leu and Phe-Leu appeared to be transported by a different carrier. 7. Kt values for di- and tripeptides, which apparently shared a common carrier, fell in a narrow range (0.5-2.2 mM). There was no clear correlation between 1/Kt value and molecular weight.

  15. An extract of Gymnema sylvestre leaves and purified gymnemic acid inhibits glucose-stimulated gastric inhibitory peptide secretion in rats.

    PubMed

    Fushiki, T; Kojima, A; Imoto, T; Inoue, K; Sugimoto, E

    1992-12-01

    Gastric inhibitory peptide release into the portal vein in response to duodenal infusion of D-glucose was studied in the presence of a leaf extract of Gymnema sylvestre, purified gymnemic acid and inhibitors of some putative glucose sensors and carriers in the intestinal lumen. Intraduodenal infusion of D-glucose significantly increased the portal immunoreactive gastric inhibitory peptide concentration in a dose-dependent manner. The increase in the portal immunoreactive gastric inhibitory peptide induced by glucose was significantly depressed by concomitantly infused leaf extract of Gymnema sylvestre, purified gymnemic acid and phlorizin but not by cytochalasin B. Mannoheptulose, which inhibits glycolysis, and procaine and lidocaine, which inhibit the vagal glucoreceptor in the lumen, did not affect portal immunoreactive gastric inhibitory peptide concentrations. These results suggest that a glucose receptor, which interacts with the leaf extract of Gymnema sylvestre, purified gymnemic acid and phlorizin, exists for the release of immunoreactive gastric inhibitory peptide and that the glucose receptor for gastric inhibitory peptide release is not likely to be identical with a glucose transporter or a vagal glucoreceptor in the lumen.

  16. Changes in vasoactive intestinal peptide, pituitary adenylate cyclase-activating polypeptide and neuropeptide Y-ergic structures of the enteric nervous system in the carcinoma of the human large intestine.

    PubMed

    Godlewski, Janusz; Łakomy, Ireneusz Mirosław

    2010-01-01

    This investigation was aimed at immunohistochemical analysis of potential changes in the enteric nervous system caused by cancer of the large intestine. In this purpose, neurons and nerve fibers of intestinal plexuses containing neuropeptides: vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP) and neuropeptide Y (NPY), in pathologically changed part of the large intestine were microscpically observed and compared. Samples were taken from patients operated due to cancer of the sigmoid colon and rectum. The number of neurons and density of nerve fibres containing neuropeptides found in sections with cancer tissues were compared to those observed in sections from the uninvolved intestinal wall. Changes relating to reductions in the number of NPY-ergic neurons and density of nerve fibres in submucous and myenteric plexuses in the sections with cancer tissues (pathological sections) were statistically significant. A statistically similar presence of VIP-ergic and PACAP-ergic neurons in the submucosal and myenteric plexuses was observed in both the pathological and control sections. On the other hand, in the pathological sections, VIP-ergic nerve fibres in the myenteric plexuses and PACAP-ergic nerve fibres in the submucosal and myenteric plexuses were found to be less dense. Analysis revealed changes in pathologically affected part of the large intestine may caused disruption of proper intestinal function. Observed changes in the neural elements which are responsible for relaxation of the intestine may suggest dysfunction in the innervation of this part of the colon.

  17. Manganese-Enhanced Magnetic Resonance Imaging for Detection of Vasoactive Intestinal Peptide Receptor 2 Agonist Therapy in a Model of Parkinson's Disease.

    PubMed

    Olson, Katherine E; Bade, Aditya N; Schutt, Charles R; Dong, Jingdong; Shandler, Scott J; Boska, Michael D; Mosley, R Lee; Gendelman, Howard E; Liu, Yutong

    2016-07-01

    Neuroprotective immunity is defined by transformation of T-cell polarity for therapeutic gain. For neurodegenerative disorders and specifically for Parkinson's disease (PD), granulocyte-macrophage colony stimulating factor or vasoactive intestinal peptide receptor 2 (VIPR2) agonists elicit robust anti-inflammatory microglial responses leading to neuronal sparing in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice. While neurotherapeutic potential was demonstrated for PD, there remain inherent limitations in translating these inventions from the laboratory to patients. One obstacle in translating such novel neurotherapeutics centers on the availability of suitable noninvasive methods to track disease progression and therapeutic efficacy. To this end, we developed manganese-enhanced magnetic resonance imaging (MEMRI) assays as a way to track a linkage between glial activation and VIPR2 agonist (LBT-3627)-induced neuroprotective immunity for MPTP-induced nigrostriatal degeneration. Notably, LBT-3627-treated, MPTP-intoxicated mice show reduced MEMRI brain signal intensities. These changes paralleled reduced astrogliosis and resulted in sparing of nigral tyrosine hydroxylase neurons. Most importantly, the data suggest that MEMRI can be developed as a biomarker tool to monitor neurotherapeutic responses that are relevant to common neurodegenerative disorders used to improve disease outcomes.

  18. Abundant distribution of locustatachykinin-like peptide in the nervous system and intestine of the cockroach Leucophaea maderae.

    PubMed

    Muren, J E; Lundquist, C T; Nässel, D R

    1995-06-29

    An antiserum raised to the locust neuropeptide locustatachykinin I (LomTK I) was used for analysis of the distribution of tachykinin-related peptide in the cockroach Leucophaea maderae. Extracts of dissected brains, suboesophageal ganglia, thoracic ganglia and midguts were separated by high performance liquid chromatography and the fractions analysed in enzyme-linked immunosorbent assay with use of the LomTK antiserum. Each of the tissues was found to contain LomTK-like immunoreactive (LomTK-LI) components with retention times corresponding approximately to synthetic LomTK I and II and callitachykinins I and II. The LomTK antiserum was also used for immunocytochemical mapping of peptide in the nervous system and intestine of L. maderae. A large number of LomTK-LI interneurons were detected in the proto-, deuto- and tritocerebrum of the brain and in the suboesophaegeal ganglion. The immunoreactive neurons supply processes to most parts of the brain: the central body, protocerebral bridge, mushroom body calyces, antennal lobes, optic lobe and most regions of the non-glomerular neuropil. A few protocerebral neurons send LomTK-LI processes to the glandular lobe of the corpora cardiaca. In each of the thoracic ganglia there are six LomTK-LI interneurons and in each of the unfused abdominal ones there are two interneurons. The fused terminal ganglion contains some additional cell bodies in the posterior neuromers. LomTK-LI cell bodies were detected in the frontal ganglion and fibres were seen in this ganglion as well as in the hypocerebral ganglion. The frontal ganglion supplies LomTK-LI processes to the muscle layer of the pharynx. The muscle layer of the midgut is innervated by LomTK-LI fibres from the stomatogastric system (oesophageal nerve and associated ganglia). Additionally the midgut contains numerous LomTK-LI endocrine cells. A number of the pharyngeal dilator muscles were also found to be innervated by LomTK-LI fibres, probably derived from cell bodies in the

  19. Mastoparan, a wasp venom peptide, stimulates release of prolactin from cultured rat anterior pituitary cells.

    PubMed

    Mau, S E; Witt, M R; Vilhardt, H

    1994-07-01

    Studies have shown that mastoparan and other amphiphilic peptides induce exocytosis of hormones from anterior pituitary cells. We have studied the effect of mastoparan on the secretion of prolactin from cultured rat anterior pituitary cells and on the concomitant functional status of signal-transducing pathways in lactotroph-enriched cell cultures. Mastoparan stimulation of prolactin secretion was dose-dependent, time-dependent, reversible and required the presence of calcium. Pretreatment of pituitary cell cultures with cholera and pertussis toxin had no effect on the secretory response, whereas encapsulation of guanosine 5-[beta-thio]diphosphate (GDP-beta-S) by reversible electropermeabilization inhibited mastoparan-stimulated secretion. Incubation of mastoparan with myo-[3H]inositol-labelled lactotroph-enriched anterior pituitary cell cultures resulted in increased formation of inositol phosphates compared with control cells, and encapsulation of GDP-beta-S blocked mastoparan-induced inositol lipid hydrolysis. Mastoparan caused translocation of protein kinase C activity from a soluble to a membrane-attached form. Mastoparan was able to increase the intracellular Ca2+ concentration in Fura-2-loaded individual lactotrophs. Omission of Ca2+ from the extracellular medium did not change the Ca2+ response in lactotrophs when stimulated with mastoparan. On the basis of these results it is concluded that mastoparan-induced release of prolactin is preceded by activation of the inositol(1,4,5)trisphosphate/diacylglycerol pathway with resulting translocation of protein kinase activity and increment in intracellular Ca2+. However, other signal-transducing pathways may be involved in the secretory process.

  20. The effect of discrete stimulation of carotid body chemoreceptors on atrial natriuretic peptide in anaesthetized dogs.

    PubMed Central

    al-Obaidi, M; Whitaker, E M; Karim, F

    1991-01-01

    1. In seven chloralose-anaesthetized and artificially ventilated beagles, the carotid sinus regions were vascularly isolated and perfused with either arterial or mixed (arterial and venous) blood (PO2 46.4 +/- 1.5 mmHg, mean +/- S.E.M.) to stimulate the chemoreceptors at constant flow and pressure. Cervical vagosympathetic trunks were ligated in all dogs, and gallamine triethiodide (2.0 mg kg-1 h-1, I.V.) was given in five dogs. Right atrial pressure was measured in all dogs, and left atrial pressure in four dogs. Mean aortic pressure was held constant (91.0 +/- 3.0 mmHg) by means of a reservoir connected to the animal via the common carotid and femoral arteries. Plasma atrial natriuretic peptide (ANP) was measured by radioimmunoassay and urinary sodium by flame photometry. 2. In seven dogs with mean carotid sinus pressure maintained at 96.0 +/- 4.3 mmHg, stimulation of the carotid chemoreceptors for 25 min produced significant increases in left atrial pressure of 41.2 +/- 3.3% (n = 4; P less than 0.005) from 5.4 +/- 0.6 cmH2O and of 30.9 +/- 4.5% (n = 7; P less than 0.002) in ANP from 31.6 +/- 2.1 pg ml-1. However, chemoreceptor stimulation produced significant decreases in urine flow rate of 26.1 +/- 1.9% (n = 9; P less than 0.001) from 0.29 +/- 0.03 ml min-1 (100 g kidney weight)-1 and sodium excretion of 29.0 +/- 2.3% (P less than 0.001) from 8.5 +/- 1.7 mumol min-1 (100 g kidney weight)-1 but right atrial pressure and heart rate did not change significantly. In three of the dogs, beta-adrenoceptor blockade by atenolol (2 mg kg-1, I.V.) greatly reduced the effects of chemoreceptor stimulation on plasma levels of ANP. 3. The results show, for the first time, that discrete stimulation of the carotid chemoreceptors caused an increase in plasma ANP levels, probably due to the reflex increase in atrial pressure that results from an inhibition of the cardiac sympathetic nerves, and an increase in venous return from a reduction of peripheral vascular capacitance. PMID

  1. Absorption-enhancing effects of gemini surfactant on the intestinal absorption of poorly absorbed hydrophilic drugs including peptide and protein drugs in rats.

    PubMed

    Alama, Tammam; Kusamori, Kosuke; Katsumi, Hidemasa; Sakane, Toshiyasu; Yamamoto, Akira

    2016-02-29

    In general, the intestinal absorption of small hydrophilic molecules and macromolecules like peptides, after oral administration is very poor. Absorption enhancers are considered to be one of the most promising agents to enhance the intestinal absorption of drugs. In this research, we focused on a gemini surfactant, a new type of absorption enhancer. The intestinal absorption of drugs, with or without sodium dilauramidoglutamide lysine (SLG-30), a gemini surfactant, was examined by an in situ closed-loop method in rats. The intestinal absorption of 5(6)-carboxyfluorescein (CF) and fluorescein isothiocyanate-dextrans (FDs) was significantly enhanced in the presence of SLG-30, such effect being reversible. Furthermore, the calcium levels in the plasma significantly decreased when calcitonin was co-administered with SLG-30, suggestive of the increased intestinal absorption of calcitonin. In addition, no significant increase in the of lactate dehydrogenase (LDH) activity or in protein release from the intestinal epithelium was observed in the presence of SLG-30, suggestive of the safety of this compound. These findings indicate that SLG-30 is an effective absorption-enhancer for improving the intestinal absorption of poorly absorbed drugs, without causing serious damage to the intestinal epithelium.

  2. Metformin Transport by a Newly Cloned Proton-Stimulated Organic Cation Transporter (Plasma Membrane Monoamine Transporter) Expressed in Human Intestine

    PubMed Central

    Zhou, Mingyan; Xia, Li; Wang, Joanne

    2009-01-01

    Metformin is a widely used oral antihyperglycemic drug for the treatment of type II diabetes mellitus. The intestinal absorption of metformin is dose-dependent and involves an active, saturable uptake process. Metformin has been shown to be transported by the human organic cation transporters 1 and 2 (hOCT1–2). We recently cloned and characterized a novel proton-activated organic cation transporter, plasma membrane monoamine transporter (PMAT). We previously showed that PMAT transports many classic organic cations (e.g., monoamine neurotransmitters, 1-methyl-4-phenylpyridinium) in a pH-dependent manner and its mRNA is expressed in multiple human tissues. The goal of this study is to investigate whether metformin is a substrate of PMAT and whether PMAT plays a role in the intestinal uptake of metformin. Using Madin-Darby canine kidney cells stably expressing human PMAT, we showed that metformin is avidly transported by PMAT, with an apparent affinity (Km = 1.32 mM) comparable to those reported for hOCT1–2. Interestingly, the concentration-velocity profile of PMAT-mediated metformin uptake is sigmoidal, with a Hill coefficient of 2.64. PMAT-mediated metformin transport is greatly stimulated by acidic pH, with the uptake rate being ~4-fold higher at pH 6.6 than at pH 7.4. Using a polyclonal antibody against PMAT, we showed that the PMAT protein (58 kDa) was expressed in human small intestine and concentrated on the tips of the mucosal epithelial layer. Taken together, our results suggest that PMAT transports metformin, is expressed in human intestine, and may play a role in the intestinal absorption of metformin and possibly other cationic drugs. PMID:17600084

  3. Intestinal peptides as circulating hormones: release of tachykinin-related peptide from the locust and cockroach midgut.

    PubMed

    Winther, A M; Nässel, D R

    2001-04-01

    Tachykinin-related peptides (TRPs) in the locust Locusta migratoria and the cockroach Leucophaea maderae have stimulatory effects on some muscles that are not innervated by TRP-containing neurons. Thus, these tissues may be affected by circulating TRPs. Here, we have investigated whether the midgut is the source of circulating TRPs. TRP-immunoreactive material in the locust midgut is found only in the endocrine cells of the gut epithelium. In both species of insect, the endocrine cells contain several isoforms of TRPs, as determined by immunocytochemistry and a combination of chromatography (HPLC) and enzyme immunoassay (ELISA). The release of TRPs was investigated by ELISA using isolated midguts of the locust and cockroach. Elevated levels of K(+) in the bathing saline induced the release of TRP from the midgut of both species. To examine the release of TRPs into the circulation in vivo, we measured haemolymph levels of TRPs in fed and starved locusts. The concentration of TRP-immunoreactive material in fed locusts was estimated to be 0.15 nmol l(-1), and this increased approximately fourfold in insects starved for 24 h. In accordance with this observation, the content of TRP-immunoreactive material in the midgut was lower in starved locusts than in fed locusts. Although part of the increased blood concentration of TRPs may be due to reduced blood volume, our data suggest that TRPs are released as hormones from the midgut of the locust and cockroach and that this release may be linked to nutritional status.

  4. F-18 Labeled Vasoactive Intestinal Peptide Analogue in the PET Imaging of Colon Carcinoma in Nude Mice

    PubMed Central

    Liu, Yuxia; Shen, Hua; Pang, Lifang; Yin, Duanzhi; Wang, Yongxian; Li, Shanqun; Shi, Hongcheng

    2013-01-01

    As large amount of vasoactive intestinal peptide (VIP) receptors are expressed in various tumors and VIP-related diseases, radiolabeled VIP provides a potential PET imaging agent for VIP receptor. However, structural modification of VIP is required before being radiolabeled and used for VIP receptor imaging due to its poor in vivo stability. As a VIP analogue, [R8, 15, 21, L17]-VIP exhibited improved stability and receptor specificity in preliminary studies. In this study, F-18 labeled [R8,15,21, L17]-VIP was produced with the radiochemical yield being as high as 33.6% ± 3% (decay-for-corrected, n = 5) achieved within 100 min, a specific activity of 255 GBq/μmol, and a radiochemical purity as high as 99% as characterized by radioactive HPLC, TLC, and SDS-Page radioautography. A biodistribution study in normal mice also demonstrated fast elimination of F-18 labeled [R8,15,21, L17]-VIP in the blood, liver, and gastrointestinal tracts. A further micro-PET imaging study in C26 colon carcinoma bearing mice confirmed the high tumor specificity, with the tumor/muscle radioactivity uptake ratio being as high as 3.03 at 60 min following injection, and no apparent radioactivity concentration in the intestinal tracts. In addition, blocking experiment and Western Blot test further confirmed its potential in PET imaging of VIP receptor-positive tumor. PMID:24459669

  5. Influence of renovascular hypertension on the distribution of vasoactive intestinal peptide in the stomach and heart of rats.

    PubMed

    Kasacka, Irena; Piotrowska, Żaneta; Janiuk, Izabela

    2015-11-01

    Arterial hypertension is associated with serious dysfunction of the cardiovascular system and digestive system. Given the relevant role of vasoactive intestinal peptide (VIP) in the regulation of digestion process, control of blood pressure and heart rate as well as cardio- and gastro-protective character of the peptide, it appeared worthwhile to undertake the research aimed at immunohistochemical identification and evaluation of VIP-positive structures in the pylorus and heart of hypertensive rats. Up to now, this issue has not been investigated. The experimental model of hypertension in rats according to Goldblatt (two-kidney one clip model of hypertension) was used in the study. The experimental material (pylorus and heart) was collected in the sixth week of the study. VIP-containing structures were evaluated using immunohistochemical and morphometric methods. The analysis of the results showed a significant increase in the number of immunoreactive VIP structures and in the intensity of immunohistochemical staining in the stomach and in the heart of hypertensive rats. Our findings indicate that VIP is an important regulator of cardiovascular and digestive system in physiological and pathological conditions. However, to better understand the exact role of VIP in hypertension further studies need to be carried out.

  6. Vasoactive intestinal peptide binding sites and fibers in the brain of the pigeon Columba livia: An autoradiographic and immunohistochemical study

    SciTech Connect

    Hof, P.R.; Dietl, M.M.; Charnay, Y.; Martin, J.L.; Bouras, C.; Palacios, J.M.; Magistretti, P.J. )

    1991-03-15

    The distribution of vasoactive intestinal peptide (VIP) binding sites in the pigeon brain was examined by in vitro autoradiography on slide-mounted sections. A fully characterized monoiodinated form of VIP, which maintains the biological activity of the native peptide, was used throughout this study. The highest densities of binding sites were observed in the hyperstriatum dorsale, archistriatum, auditory field L of neostriatum, area corticoidea dorsolateralis and temporo-parieto-occipitalis, area parahippocampalis, tectum opticum, nucleus dorsomedialis anterior thalami, and in the periventricular area of the hypothalamus. Lower densities of specific binding occurred in the neostriatum, hyperstriatum ventrale and nucleus septi lateralis, dorsolateral area of the thalamus, and lateral and posteromedial hypothalamus. Very low to background levels of VIP binding were detected in the ectostriatum, paleostriatum primitivum, paleostriatum augmentatum, lobus parolfactorius, nucleus accumbens, most of the brainstem, and the cerebellum. The distribution of VIP-containing fibers and terminals was examined by indirect immunofluorescence using a polyclonal antibody against porcine VIP. Fibers and terminals were observed in the area corticoidea dorsolateralis, area parahippocampalis, hippocampus, hyperstriatum accessorium, hyperstriatum dorsale, archistriatum, tuberculum olfactorium, nuclei dorsolateralis and dorsomedialis of the thalamus, and throughout the hypothalamus and the median eminence. Long projecting fibers were visualized in the tractus septohippocampalis. In the brainstem VIP immunoreactive fibers and terminals were observed mainly in the substantia grisea centralis, fasciculus longitudinalis medialis, lemniscus lateralis, and in the area surrounding the nuclei of the 7th, 9th, and 10th cranial nerves.

  7. Collagen peptides ameliorate intestinal epithelial barrier dysfunction in immunostimulatory Caco-2 cell monolayers via enhancing tight junctions.

    PubMed

    Chen, Qianru; Chen, Oliver; Martins, Isabela M; Hou, Hu; Zhao, Xue; Blumberg, Jeffrey B; Li, Bafang

    2017-03-22

    Dysfunction of the intestinal barrier plays a key role in the pathogenesis of inflammatory bowel disease (IBD) and multiple organ failure. The effect of Alaska pollock skin-derived collagen and its 3 tryptic hydrolytic fractions, HCP (6 kDa retentate), MCP (3 kDa retentate) and LCP (3 kDa permeate) on TNF-α induced barrier dysfunction was investigated in Caco-2 cell monolayers. TNF-α induced barrier dysfunction was significantly attenuated by the collagen and its peptide fractions, especially LCP, compared to TNF-α treated controls (P < 0.05). Compared to a negative control, 24 h pre-incubation with 2 mg mL(-1) LCP significantly alleviated the TNF-α induced breakdown of the tight junction protein ZO-1 and occludin and inhibited MLC phosphorylation and MLCK expression. The activation of NFκB and Elk-1 was suppressed by LCP. Thus, collagen peptides may attenuate TNF-α induced barrier dysfunction of Caco-2 cells by inhibiting the NFκB and ERK1/2-mediated MLCK pathway with associated decreases in ZO-1 and occludin protein expression.

  8. Amino acid and peptide absorption after proximal small intestinal resection in the rat.

    PubMed Central

    Garrido, A B; Freeman, H J; Chung, Y C; Kim, Y S

    1979-01-01

    In experimental animals with massive proximal intestinal resection, in vivo ileal absorption of an amino acid mixture containing L-leucine and glycine as well as two different dipeptides, L-leucyl-glycine and glycyl-L-leucine, were compared. Both amino acid and dipeptide absorption were markedly enhanced in the ileal segments. However, the absorption rates from the two perfused dipeptides differed. L-leucine absorption from L-leucyl-glycine was much greater than from glycyl-L-leucine. Brush border amino-peptidase activities after resection were also increased but dissociation between absorption and hydrolytic activity occurred. This study indicates that certain dipeptides are handled differently by adapting ileal segments. Furthermore, the changes observed probably reflect mucosal cellular hyperplasia occurring in association with intestinal adaptation. PMID:428822

  9. Microfluidic Device for the Selective Chemical Stimulation of Neurons and Characterization of Peptide Release with Mass Spectrometry

    PubMed Central

    2012-01-01

    Neuropeptides are synthesized in and released from neurons and are involved in a wide range of physiological processes, including temperature homeostasis, learning, memory, and disease. When working with sparse neuronal networks, the ability to collect and characterize small sample volumes is important as neurons often release only a small proportion of their mass-limited content. Microfluidic systems are well suited for the study of neuropeptides. They offer the ability to control and manipulate the extracellular environment and small sample volumes, thereby reducing the dilution of peptides following release. We present an approach for the culture and stimulation of a neuronal network within a microfluidic device, subsequent collection of the released peptides, and their detection via mass spectrometry. The system employs microvalve-controlled stimulation channels to selectively stimulate a low-density neuronal culture, allowing us to determine the temporal onset of peptide release. Released peptides from the well-characterized, peptidergic bag cell neurons of Aplysia californica were collected and their temporal pattern of release was characterized with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. We show a robust difference in the timing of release for chemical solutions containing elevated K+ (7 ± 3 min), when compared to insulin (19 ± 7 min) (p < 0.000 01). PMID:23004687

  10. Complement peptide C3a stimulates neural plasticity after experimental brain ischaemia.

    PubMed

    Stokowska, Anna; Atkins, Alison L; Morán, Javier; Pekny, Tulen; Bulmer, Linda; Pascoe, Michaela C; Barnum, Scott R; Wetsel, Rick A; Nilsson, Jonas A; Dragunow, Mike; Pekna, Marcela

    2017-02-01

    Ischaemic stroke induces endogenous repair processes that include proliferation and differentiation of neural stem cells and extensive rewiring of the remaining neural connections, yet about 50% of stroke survivors live with severe long-term disability. There is an unmet need for drug therapies to improve recovery by promoting brain plasticity in the subacute to chronic phase after ischaemic stroke. We previously showed that complement-derived peptide C3a regulates neural progenitor cell migration and differentiation in vitro and that C3a receptor signalling stimulates neurogenesis in unchallenged adult mice. To determine the role of C3a-C3a receptor signalling in ischaemia-induced neural plasticity, we subjected C3a receptor-deficient mice, GFAP-C3a transgenic mice expressing biologically active C3a in the central nervous system, and their respective wild-type controls to photothrombotic stroke. We found that C3a overexpression increased, whereas C3a receptor deficiency decreased post-stroke expression of GAP43 (P < 0.01), a marker of axonal sprouting and plasticity, in the peri-infarct cortex. To verify the translational potential of these findings, we used a pharmacological approach. Daily intranasal treatment of wild-type mice with C3a beginning 7 days after stroke induction robustly increased synaptic density (P < 0.01) and expression of GAP43 in peri-infarct cortex (P < 0.05). Importantly, the C3a treatment led to faster and more complete recovery of forepaw motor function (P < 0.05). We conclude that C3a-C3a receptor signalling stimulates post-ischaemic neural plasticity and intranasal treatment with C3a receptor agonists is an attractive approach to improve functional recovery after ischaemic brain injury.

  11. An optimized B lymphocyte stimulator (BLyS) antagonist peptide inhibits the interaction of BLyS with BCMA.

    PubMed

    Tian, Yu; Zhu, Yan-Feng; Wu, Zhen; Feng, Jian-Nan; Li, Yan; Shen, Bei-Fen; Sun, Jian

    2013-04-01

    B lymphocyte stimulator (BLyS) antagonists are new therapeutic reagents for treating the autoimmune diseases. Peptibodies can inhibit the bioactivity of BLyS, the same as other BLyS antagonists: decoyed BLyS receptors and anti-BLyS antibodies. In this study, a new optimized BLyS antagonist peptide was designed according to our previous work by the computer-aided homology modeling. Competitive ELISA showed that the peptide at 100 μg/ml could inhibit 54 % of the BCMA-Fc binding to BLyS. To maintain its stability and spatial conformation, the peptide was fused to human IgG1 Fc to form a peptide-Fc fusion protein-a novel peptibody by gene engineering. ELISA indicated that the peptibody could bind with BLyS in dosage-dependent manner as BCMA-Fc did. This study highlights the possibility of designing and optimizing BLyS antagonist peptides with high biopotency by the computer-aided design. Thus, these peptides could neutralize BLyS activity and be potential antagonists to treat autoimmune diseases related with BLyS overexpression.

  12. IGF1 stimulates crypt expansion via differential activation of 2 intestinal stem cell populations.

    PubMed

    Van Landeghem, Laurianne; Santoro, M Agostina; Mah, Amanda T; Krebs, Adrienne E; Dehmer, Jeffrey J; McNaughton, Kirk K; Helmrath, Michael A; Magness, Scott T; Lund, P Kay

    2015-07-01

    Insulin-like growth factor 1 (IGF1) has potent trophic effects on normal or injured intestinal epithelium, but specific effects on intestinal stem cells (ISCs) are undefined. We used Sox9-enhanced green fluorescent protein (EGFP) reporter mice that permit analyses of both actively cycling ISCs (Sox9-EGFP(Low)) and reserve/facultative ISCs (Sox9-EGFP(High)) to study IGF1 action on ISCs in normal intestine or during crypt regeneration after high-dose radiation-induced injury. We hypothesized that IGF1 differentially regulates proliferation and gene expression in actively cycling and reserve/facultative ISCs. IGF1 was delivered for 5 days using subcutaneously implanted mini-pumps in uninjured mice or after 14 Gy abdominal radiation. ISC numbers, proliferation, and transcriptome were assessed. IGF1 increased epithelial growth in nonirradiated mice and enhanced crypt regeneration after radiation. In uninjured and regenerating intestines, IGF1 increased total numbers of Sox9-EGFP(Low) ISCs and percentage of these cells in M-phase. IGF1 increased percentages of Sox9-EGFP(High) ISCs in S-phase but did not expand this population. Microarray revealed that IGF1 activated distinct gene expression signatures in the 2 Sox9-EGFP ISC populations. In vitro IGF1 enhanced enteroid formation by Sox9-EGFP(High) facultative ISCs but not Sox9-EGFP(Low) actively cycling ISCs. Our data provide new evidence that IGF1 activates 2 ISC populations via distinct regulatory pathways to promote growth of normal intestinal epithelium and crypt regeneration after irradiation.

  13. Neural regulation of intestinal nutrient absorption.

    PubMed

    Mourad, Fadi H; Saadé, Nayef E

    2011-10-01

    The nervous system and the gastrointestinal (GI) tract share several common features including reciprocal interconnections and several neurotransmitters and peptides known as gut peptides, neuropeptides or hormones. The processes of digestion, secretion of digestive enzymes and then absorption are regulated by the neuro-endocrine system. Luminal glucose enhances its own absorption through a neuronal reflex that involves capsaicin sensitive primary afferent (CSPA) fibres. Absorbed glucose stimulates insulin release that activates hepatoenteric neural pathways leading to an increase in the expression of glucose transporters. Adrenergic innervation increases glucose absorption through α1 and β receptors and decreases absorption through activation of α2 receptors. The vagus nerve plays an important role in the regulation of diurnal variation in transporter expression and in anticipation to food intake. Vagal CSPAs exert tonic inhibitory effects on amino acid absorption. It also plays an important role in the mediation of the inhibitory effect of intestinal amino acids on their own absorption at the level of proximal or distal segment. However, chronic extrinsic denervation leads to a decrease in intestinal amino acid absorption. Conversely, adrenergic agonists as well as activation of CSPA fibres enhance peptides uptake through the peptide transporter PEPT1. Finally, intestinal innervation plays a minimal role in the absorption of fat digestion products. Intestinal absorption of nutrients is a basic vital mechanism that depends essentially on the function of intestinal mucosa. However, intrinsic and extrinsic neural mechanisms that rely on several redundant loops are involved in immediate and long-term control of the outcome of intestinal function.

  14. Specific vaginal lactobacilli suppress the inflammation induced by lipopolysaccharide stimulation through downregulation of toll-like receptor 4 expression in human embryonic intestinal epithelial cells

    PubMed Central

    TOBITA, Keisuke; WATANABE, Itsuki; SAITO, Masanori

    2016-01-01

    Vaginal lactobacilli (VLB) spread from the mother to the infant during vaginal delivery. However, the effects of VLB on infant intestinal function remain unclear. We investigated the probiotic function and immune effects of VLB on the human embryonic intestinal epithelial cell line INT-407. VLB survived artificial gastric juice and adhered to INT-407 cells. Exposure of INT-407 cells to VLB attenuated both the lipopolysaccharide (LPS)-induced stimulation of interleukin-8 and tumor necrosis factor alpha production and the LPS-stimulated upregulation of TLR4 expression. These results suggest that specific VLB suppresses the inflammation induced by LPS stimulation through downregulation of TLR4 expression in human embryonic intestinal epithelial cells. PMID:28243550

  15. Water absorption and bicarbonate secretion in the intestine of the sea bream are regulated by transmembrane and soluble adenylyl cyclase stimulation.

    PubMed

    Carvalho, Edison S M; Gregório, Sílvia F; Power, Deborah M; Canário, Adelino V M; Fuentes, Juan

    2012-12-01

    In the marine fish intestine luminal, HCO₃⁻ can remove divalent ions (calcium and magnesium) by precipitation in the form of carbonate aggregates. The process of epithelial HCO₃⁻ secretion is under endocrine control, therefore, in this study we aimed to characterize the involvement of transmembrane (tmACs) and soluble (sACs) adenylyl cyclases on the regulation of bicarbonate secretion (BCS) and water absorption in the intestine of the sea bream (Sparus aurata). We observed that all sections of sea bream intestine are able to secrete bicarbonate as measured by pH-Stat in Ussing chambers. In addition, gut sac preparations reveal net water absorption in all segments of the intestine, with significantly higher absorption rates in the anterior intestine that in the rectum. BCS and water absorption are positively correlated in all regions of the sea bream intestinal tract. Furthermore, stimulation of tmACs (10 μM FK + 500 μM IBMX) causes a significant decrease in BCS, bulk water absorption and short circuit current (Isc) in a region dependent manner. In turn, stimulation of sACs with elevated HCO₃⁻ results in a significant increase in BCS, and bulk water absorption in the anterior intestine, an action completely reversed by the sAC inhibitor KH7 (200 μM). Overall, the results reveal a functional relationship between BCS and water absorption in marine fish intestine and modulation by tmACs and sAC. In light of the present observations, it is hypothesized that the endocrine effects on intestinal BCS and water absorption mediated by tmACs are locally and reciprocally modulated by the action of sACs in the fish enterocyte, thus fine-tuning the process of carbonate aggregate production in the intestinal lumen.

  16. Carrier-mediated intestinal absorption of valacyclovir, the L-valyl ester prodrug of acyclovir: 1. Interactions with peptides, organic anions and organic cations in rats.

    PubMed

    Sinko, P J; Balimane, P V

    1998-05-01

    The mechanism of intestinal transport of valacyclovir (VACV), the L-valyl ester prodrug of acyclovir, was investigated in rats using an in situ intestinal perfusion technique. VACV demonstrates an oral bioavailability that is three to five time greater than acyclovir, concentration dependent, and saturable in humans. Homogenate and perfused buffer stability results demonstrated that VACV was increasingly unstable with increasing pH. VACV was converted to ACV in a concentration dependent manner during a single pass through the intestinal segment. Perfusions were performed at 37 degrees C, pH 6.5, and under iso-osmotic conditions (290 +/- 10 mOsm L-1). Intestinal outlet concentrations were corrected for VACV that was converted to ACV during the perfusion. The effective dimensionless intestinal permeability (P*e) of VACV was concentration dependent, saturable (intrinsic Km = 1.2 +/- 0.7 mM), and significantly reduced (p < 0.05) in the presence of peptide analogues (amoxicillin, ampicillin, cefadroxil, and cephradine), by the organic anion, p-amino hippuric acid and by the organic cation quinine. VACV transport was not inhibited by classical nucleoside competitive substrates or inhibitors or by valine. These results suggest that H(+)-oligopeptide, H(+)-organic cation, and organic anion transporters are involved in the small intestinal uptake of VACV. The permeability of VACV in the colon was very low, indicating that VACV is predominantly absorbed from the small intestine. VACV P*e was not altered in the presence of glucose-induced convective fluid flow, suggesting that carrier-mediated, transcellular uptake is the predominant absorption pathway of VACV in rat small intestine. Based on these results, the oral bioavailability of VACV appears to be significantly influenced by the preabsorptive conversion of VACV to the poorly absorbed ACV, by the involvement of multiple transporters in VACV small-intestinal uptake, and by the low permeability of VACV in the colon.

  17. Effects of the antimicrobial peptide cecropin AD on performance and intestinal health in weaned piglets challenged with Escherichia coli.

    PubMed

    Wu, Shudan; Zhang, Fengrui; Huang, Zhimin; Liu, Hong; Xie, Chunyuan; Zhang, Jiang; Thacker, Philip A; Qiao, Shiyan

    2012-06-01

    This study was conducted to determine the effects of the antimicrobial peptide cecropin on performance and intestinal health in piglets. Newly weaned barrows were randomly assigned to one of three treatments (n=8), including a corn-soybean basal diet or similar diets supplemented with antibiotics (100 mg/kg kitasamycin plus 800 mg/kg colistin sulfate) or 400 mg/kg cecropin AD. On day 13, all piglets were orally challenged with 10(9)CFU/mL of Escherichia coli K88. On day 19, all piglets were euthanized and sampled. Before challenge, piglets fed antibiotics had greater weight gain, feed efficiency, nitrogen and energy retention than the control (P<0.05). E. coli challenge decreased weight gain, feed intake and feed efficiency for the control piglets (P<0.05) but not for the antibiotic or cecropin AD treated piglets. The incidence of diarrhea post-challenge in the antibiotic and cecropin AD treatments decreased compared with the control piglets. The total viable counts of cecal E. coli were lower while the Lactobacilli counts were higher in the antibiotic and cecropin AD treatments compared with the control (P<0.05). Cecropin AD treatment decreased total aerobes while increasing total anaerobes in the ileum (P<0.05). A higher villus height to crypt depth ratio in the jejunum and ileum as well as a deeper crypt depth in the jejunum and higher villus height in the ileum were observed in piglets fed antibiotics or cecropin AD compared with control piglets (P<0.05). Piglets fed the control diet had lower levels of secretory IgA in their jejunum and lower serum IgA, IgG, interleukin-1β and interleukin-6 compared with the other treatments (P<0.05). Overall, these data suggest that cecropin AD enhances pig performance through increasing immune status and nitrogen and energy retention as well as reducing intestinal pathogens in weaned piglets.

  18. Vasoactive intestinal peptide-induced expression of cytochrome P450 cholesterol side-chain cleavage and 17 alpha-hydroxylase enzyme activity in hen granulosa cells.

    PubMed

    Johnson, A L; Li, Z; Gibney, J A; Malamed, S

    1994-08-01

    Experiments were conducted to determine whether vasoactive intestinal peptide (VIP) can regulate expression of cytochrome P450 side-chain cleavage (P450scc) and P450 17 alpha-hydroxylase (P450 17 alpha-OH) mRNA levels and enzyme activity in granulosa cells from nonhierarchal (6-8-mm) follicles. Initial studies demonstrated that immunoreactive VIP is localized within the theca (but not granulosa) layer of both resting (< 0.5-mm follicles) and 6-8-mm follicles, thus providing a potential paracrine mechanism of action for VIP. While short-term (3 h) incubation of granulosa cells with VIP (0.001-1.0 microM) failed to stimulate progesterone production from 6-8-mm follicle granulosa cells, a 4-h culture period in the presence of VIP resulted in increased cyclic AMP (cAMP) accumulation, and a 24-h culture period resulted in progesterone synthesis and increased P450scc mRNA levels; control levels of each endpoint measurement were not altered within the period observed. By contrast, culture with the growth factor transforming growth factor alpha (TGF alpha) in the presence of VIP (1 microM) prevented increases in P450scc mRNA levels and progesterone production. Similar effects of VIP and TGF alpha in the presence of VIP were demonstrated for P450 17 alpha-OH mRNA levels and enzyme activity. Finally, there was an additive effect of VIP (0.1 microM) plus recombinant human (rh) FSH (100 mIU) on the initiation of progesterone production in cultured 6-8-mm follicle granulosa cells compared to the addition of VIP or rhFSH alone.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. A chimeric peptide of intestinal trefoil factor containing cholesteryl ester transfer protein B cell epitope significantly inhibits atherosclerosis in rabbits after oral administration.

    PubMed

    Qi, Gaofu; Li, Jingjing; Wang, Shengying; Xin, Shanshan; Du, Peng; Zhang, Qingye; Zhao, Xiuyun

    2011-04-01

    Vaccination against cholesteryl ester transfer protein (CETP) is proven to be effective for inhibiting atherosclerosis in animal models. In this study, the proteases-resistant intestinal trefoil factor (TFF3) was used as a molecular vehicle to construct chimeric TFF3 (cTFF3) containing CETP B cell epitope and tetanus toxin helper T cell epitope. It was found that cTFF3 still preserved a trefoil structure, and can resist proteases digestion in vitro. After oral immunization with cTFF3, the CETP-specific IgA and IgG could be found in intestine lavage fluid and serum, and the anti-CETP antibodies could inhibit partial CETP activity to increase high-density lipoprotein cholesterol, decrease low-density lipoprotein cholesterol, and inhibit atherosclerosis in animals. Therefore, TFF3 is a potential molecular vehicle for developing oral peptide vaccines. Our research highlights a novel strategy for developing oral peptide vaccines in the future.

  20. Targeting of follicle stimulating hormone peptide-conjugated dendrimers to ovarian cancer cells

    NASA Astrophysics Data System (ADS)

    Modi, Dimple A.; Sunoqrot, Suhair; Bugno, Jason; Lantvit, Daniel D.; Hong, Seungpyo; Burdette, Joanna E.

    2014-02-01

    Ovarian cancer is the most lethal gynecological malignancy. Current treatment modalities include a combination of surgery and chemotherapy, which often lead to loss of fertility in premenopausal women and a myriad of systemic side effects. To address these issues, we have designed poly(amidoamine) (PAMAM) dendrimers to selectively target the follicle stimulating hormone receptor (FSHR), which is overexpressed by tumorigenic ovarian cancer cells but not by immature primordial follicles and other non-tumorigenic cells. Fluorescein-labeled generation 5 (G5) PAMAM dendrimers were conjugated with the binding peptide domain of FSH (FSH33) that has a high affinity to FSHR. The targeted dendrimers exhibited high receptor selectivity to FSHR-expressing OVCAR-3 cells, resulting in significant uptake and downregulation of an anti-apoptotic protein survivin, while showing minimal interactions with SKOV-3 cells that do not express FSHR. The selectivity of the FSH33-targeted dendrimers was further validated in 3D organ cultures of normal mouse ovaries. Immunostaining of the conjugates revealed their selective binding and uptake by ovarian surface epithelium (OSE) cells that express FSHR, while sparing the immature primordial follicles. In addition, an in vivo study monitoring tissue accumulation following a single intraperitoneal (i.p.) injection of the conjugates showed significantly higher accumulation of FSH33-targeted dendrimers in the ovary and oviduct compared to the non-targeted conjugates. These proof-of-concept findings highlight the potential of these FSH33-targeted dendrimers to serve as a delivery platform for anti-ovarian cancer drugs, while reducing their systemic side effects by preventing nonspecific uptake by the primordial follicles.Ovarian cancer is the most lethal gynecological malignancy. Current treatment modalities include a combination of surgery and chemotherapy, which often lead to loss of fertility in premenopausal women and a myriad of systemic side

  1. Radioimmunoassay of relaxin-like gonad-stimulating peptide in the starfish Patiria (=Asterina) pectinifera.

    PubMed

    Yamamoto, Kazutoshi; Kiyomoto, Masato; Katayama, Hidekazu; Mita, Masatoshi

    2017-03-01

    A relaxin-like gonad-stimulating peptide (RGP) from starfish Patiria (=Asterina) pectinifera is the first identified invertebrate gonadotropin for final gamete maturation. An antiserum against P. pectinifera RGP (PpeRGP) was produced by immunizing rabbits with a PpeRGP sulfanyl-polyethylene glycol derivative conjugated with keyhole limpet hemocyanin (KLH) as the antigen. The antiserum was used for the development of a specific and sensitive radioimmunoassay (RIA) for the measurement of RGP. In binding experiments using radioiodinated PpeRGP and antiserum against PpeRGP, a displacement curve was obtained using radioinert PpeRGP. The sensitivity of the RIA, defined as the amount of PpeRGP that significantly decreased the counts by 2 SD from the 100% bound point, averaged 0.040±0.002pmol PpeRGP per 100μl assay buffer (0.40±0.02nM) in 10 assays. Intra-assay and inter-assay coefficients of variation were 6.1% and 2.7%, respectively. Serial dilution of whole homogenates from the radial nerve cords and circumoral nerve-rings of P. pectinifera produced displacement curves parallel to the PpeRGP standard. Thus, the amounts of PpeRGP were determined as 1.54±0.09pmol/mg wet weight of radial nerves and 0.87±0.04pmol/mg wet weight of nerve-rings, respectively. On contrary, pyloric stomach, pyloric caeca, tube-feet, ovaries, testes, and ovarian follicle cells did not react in the RIA system. Furthermore, the A- and B-chains of PpeRGP, Asterias amurensis RGP, bovine insulin, and human relaxin did not show cross-reactivity in the RIA. These results strongly suggest that the RIA system is a highly specific and sensitive with respect to PpeRGP.

  2. Subpopulation-Specific Transcriptome Analysis of Competence-Stimulating-Peptide-Induced Streptococcus mutans▿†

    PubMed Central

    Lemme, André; Gröbe, Lothar; Reck, Michael; Tomasch, Jürgen; Wagner-Döbler, Irene

    2011-01-01

    Competence-stimulating-peptide (CSP)-mediated competence development in Streptococcus mutans is a transient and biphasic process, since only a subpopulation induces the expression of ComX in the presence of CSP, and the activation of the DNA uptake machinery in this fraction shuts down ∼3 to 4 h postinduction. Here, we combine for the first time, to our knowledge, the bacterial flow-cytometric sorting of cells and subpopulation-specific transcriptome analysis of both the competent and noncompetent fraction of CSP-treated S. mutans cells. Sorting was guided by a ComX-green fluorescent protein (ComX-GFP) reporter, and the transcriptome analysis demonstrated the successful combination of both methods, because a strong enrichment of transcripts for comX and its downstream genes was achieved. Three two-component systems were expressed in the competent fraction, and among them was ComDE. Moreover, the recently identified regulator system ComR/S was expressed exclusively in the competent fraction. In contrast, the expression of bacteriocin-related genes was at the same level in all cells. GFP reporter strains for ComE and CipB (mutacin V) confirmed this expression pattern on the single-cell level. Fluorescence microscopy revealed that some ComX-expressing cells committed autolysis in an early stage of competence initiation. In viable ComX-expressing cells, the uptake of DNA could be shown on the single-cell level. This study demonstrates that all cells in the population respond to CSP through the activation of bacteriocin-related genes. Some of these cells start to activate ComX expression but then segregate into two subpopulations, one becoming competent and another one that lyses, resulting in intrapopulation diversity. PMID:21317319

  3. PI3K p110α/Akt signaling negatively regulates secretion of the intestinal peptide neurotensin through interference of granule transport.

    PubMed

    Li, Jing; Song, Jun; Cassidy, Margaret G; Rychahou, Piotr; Starr, Marlene E; Liu, Jianyu; Li, Xin; Epperly, Garretson; Weiss, Heidi L; Townsend, Courtney M; Gao, Tianyan; Evers, B Mark

    2012-08-01

    Neurotensin (NT), an intestinal peptide secreted from N cells in the small bowel, regulates a variety of physiological functions of the gastrointestinal tract, including secretion, gut motility, and intestinal growth. The class IA phosphatidylinositol 3-kinase (PI3K) family, which comprised of p110 catalytic (α, β and δ) and p85 regulatory subunits, has been implicated in the regulation of hormone secretion from endocrine cells. However, the underlying mechanisms remain poorly understood. In particular, the role of PI3K in intestinal peptide secretion is not known. Here, we show that PI3K catalytic subunit, p110α, negatively regulates NT secretion in vitro and in vivo. We demonstrate that inhibition of p110α, but not p110β, induces NT release in BON, a human endocrine cell line, which expresses NT mRNA and produces NT peptide in a manner analogous to N cells, and QGP-1, a pancreatic endocrine cell line that produces NT peptide. In contrast, overexpression of p110α decreases NT secretion. Consistently, p110α-inhibition increases plasma NT levels in mice. To further delineate the mechanisms contributing to this effect, we demonstrate that inhibition of p110α increases NT granule trafficking by up-regulating α-tubulin acetylation; NT secretion is prevented by overexpression of HDAC6, an α-tubulin deacetylase. Moreover, ras-related protein Rab27A (a small G protein) and kinase D-interacting substrate of 220 kDa (Kidins220), which are associated with NT granules, play a negative and positive role, respectively, in p110α-inhibition-induced NT secretion. Our findings identify the critical role and novel mechanisms for the PI3K signaling pathway in the control of intestinal hormone granule transport and release.

  4. PI3K p110α/Akt Signaling Negatively Regulates Secretion of the Intestinal Peptide Neurotensin Through Interference of Granule Transport

    PubMed Central

    Li, Jing; Song, Jun; Cassidy, Margaret G.; Rychahou, Piotr; Starr, Marlene E.; Liu, Jianyu; Li, Xin; Epperly, Garretson; Weiss, Heidi L.; Townsend, Courtney M.; Gao, Tianyan

    2012-01-01

    Neurotensin (NT), an intestinal peptide secreted from N cells in the small bowel, regulates a variety of physiological functions of the gastrointestinal tract, including secretion, gut motility, and intestinal growth. The class IA phosphatidylinositol 3-kinase (PI3K) family, which comprised of p110 catalytic (α, β and δ) and p85 regulatory subunits, has been implicated in the regulation of hormone secretion from endocrine cells. However, the underlying mechanisms remain poorly understood. In particular, the role of PI3K in intestinal peptide secretion is not known. Here, we show that PI3K catalytic subunit, p110α, negatively regulates NT secretion in vitro and in vivo. We demonstrate that inhibition of p110α, but not p110β, induces NT release in BON, a human endocrine cell line, which expresses NT mRNA and produces NT peptide in a manner analogous to N cells, and QGP-1, a pancreatic endocrine cell line that produces NT peptide. In contrast, overexpression of p110α decreases NT secretion. Consistently, p110α-inhibition increases plasma NT levels in mice. To further delineate the mechanisms contributing to this effect, we demonstrate that inhibition of p110α increases NT granule trafficking by up-regulating α-tubulin acetylation; NT secretion is prevented by overexpression of HDAC6, an α-tubulin deacetylase. Moreover, ras-related protein Rab27A (a small G protein) and kinase D-interacting substrate of 220 kDa (Kidins220), which are associated with NT granules, play a negative and positive role, respectively, in p110α-inhibition-induced NT secretion. Our findings identify the critical role and novel mechanisms for the PI3K signaling pathway in the control of intestinal hormone granule transport and release. PMID:22700584

  5. Role of Vagal Innervation in Diurnal Rhythm of Intestinal Peptide Transporter 1 (PEPT1)

    PubMed Central

    Qandeel, Hisham G.; Alonso, Fernando; Hernandez, David J.; Duenes, Judith A.; Zheng, Ye; Scow, Jeffrey S.; Sarr, Michael G.

    2010-01-01

    BACKGROUND: Protein is absorbed predominantly as di/tripeptides via H+/peptide cotransporter-1 (PEPT1). We demonstrated previously diurnal variations in expression and function of duodenal and jejunal but not ileal PEPT1; neural regulation of this pattern is unexplored. HYPOTHESIS: Complete abdominal vagotomy abolishes diurnal variations in gene expression and transport function of PEPT1. METHODS: 24 rats maintained in a 12-h light/dark room [6AM-6PM] underwent abdominal vagotomy; 24 other rats were controls. Four weeks later, mucosal levels of mRNA and protein were measured at 9AM, 3PM, 9PM, and 3AM (n=6 each) by quantitative real time-PCR and Western blots, respectively; transporter-mediated uptake of di-peptide (Gly-Sar) was measured by the everted-sleeve technique. RESULTS: Diurnal variation in mRNA, as in controls, was retained post-vagotomy in duodenum and jejunum (peak at 3PM, p<0.05) but not in ileum. Diurnal variations in expression of protein and Gly-Sar uptake, however, were absent post-vagotomy (p>0.3). Similar to controls, maximal uptake was in jejunum after vagotomy (Vmax-nmol/cm/min: jejunum vs. duodenum and ileum; 163 vs. 88 and 71 at 3AM; p<0.04); Km remained unchanged. CONCLUSIONS: Vagal innervation appears to mediate in part diurnal variations in protein expression and transport function of PEPT1, but not diurnal variation in mRNA expression of PEPT1. PMID:19707837

  6. Hypothalamic paraventricular nucleus stimulation reduces intestinal injury in rats with ulcerative colitis

    PubMed Central

    Deng, Quan-Jun; Deng, Ding-Jing; Che, Jin; Zhao, Hai-Rong; Yu, Jun-Jie; Lu, Yong-Yu

    2016-01-01

    AIM: To investigate the effect and mechanism of stimulation of the hypothalamic paraventricular nucleus with glutamate acid in rats with ulcerative colitis (UC). METHODS: The rats were anesthetized with 10% chloral hydrate via abdominal injection and treated with an equal volume of TNBS + 50% ethanol enema, injected into the upper section of the anus with the tail facing up. Colonic damage scores were calculated after injecting a certain dose of glutamic acid into the paraventricular nucleus (PVN), and the effect of the nucleus tractus solitarius (NTS) and vagus nerve in alleviating UC injury through chemical stimulation of the PVN was observed in rats. Expression changes of C-myc, Apaf-1, caspase-3, interleukin (IL)-6, and IL-17 during the protection against UC injury through chemical stimulation of the PVN in rats were detected by Western blot. Malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in colon tissues of rats were measured by colorimetric methods. RESULTS: Chemical stimulation of the PVN significantly reduced UC in rats in a dose-dependent manner. The protective effects of the chemical stimulation of the PVN on rats with UC were eliminated after chemical damage to the PVN. After glutamate receptor antagonist kynurenic acid was injected into the PVN, the protective effects of the chemical stimulation of the PVN were eliminated in rats with UC. After AVP-Vl receptor antagonist ([Deamino-penl, val4, D-Arg8]-vasopressin) was injected into NTS or bilateral chemical damage to NTS, the protective effect of the chemical stimulation of PVN on UC was also eliminated. After chemical stimulation of the PVN, SOD activity increased, MDA content decreased, C-myc protein expression significantly increased, caspase-3 and Apaf-1 protein expression significantly decreased, and IL-6 and IL-17 expression decreased in colon tissues in rats with UC. CONCLUSION: Chemical stimulation of the hypothalamic PVN provides a protective effect against UC injury in

  7. Measurement of vasoactive intestinal peptide using a competitive fluorescent microsphere immunoassay or ELISA in human blood samples.

    PubMed

    Song, Eun Young; VanDunk, Cassandra; Kuddo, Thea; Nelson, Phillip G

    2005-05-01

    The concentration of Vasoactive Intestinal Peptide (VIP) as measured by recycling immunoaffinity chromatography (RIC) has been reported to be elevated in the blood of patients with autism as compared with normal subjects. In this study, we have developed a "Competitive Fluorescent Microsphere Immunoassay" (cFMI) in which VIP competes with biotinylated VIP in binding to polyclonal antibodies on microspheres. The results were obtained using the Luminex100 system. We measured VIP in serum, plasma, and material eluted from dried blood spots on filter paper with both the cFMI and an ELISA procedure. We found that a purification procedure was necessary for obtaining useful results from plasma and serum, however, a preincubation step was required with the blood eluates. This newly developed cFMI was more sensitive (2.5 vs. 20.0 pg/ml), and more reproducible than the ELISA. To get accurate measurements of VIP in eluted material high sensitivity is especially important. Thus, the cFMI using the Luminex system has definite advantages over a conventional ELISA including the possibility that samples can be assayed at higher dilutions. We have determined that the VIP concentrations of serum, plasma, and dried blood spot eluate specimens as measured with the cFMI assay system were similar to those measured with ELISA. Thus, the new cFMI using Luminex system may be useful for detection of VIP in human blood samples.

  8. Vasoactive Intestinal Peptide modulates trophoblast-derived cell line function and interaction with phagocytic cells through autocrine pathways

    PubMed Central

    Vota, Daiana; Paparini, Daniel; Hauk, Vanesa; Toro, Ayelén; Merech, Fatima; Varone, Cecilia; Ramhorst, Rosanna; Pérez Leirós, Claudia

    2016-01-01

    Trophoblast cells migrate and invade the decidual stroma in a tightly regulated process to maintain immune homeostasis at the maternal-placental interface during the first weeks of pregnancy. Locally synthesized factors modulate trophoblast cell function and their interaction with maternal leukocytes to promote the silent clearance of apoptotic cells. The vasoactive intestinal peptide (VIP) is a pleiotropic polypeptide with trophic and anti-inflammatory effects in murine pregnancy models. We explored the effect of VIP on two human first trimester trophoblast cell lines, particularly on their migration, invasiveness and interaction with phagocytic cells, and the signalling and regulatory pathways involved. We found that VIP enhanced trophoblast cell migration and invasion through the activation of high affinity VPAC receptors and PKA-CRE signalling pathways. VIP knocked-down trophoblast cells showed reduced migration in basal and leukemic inhibitor factor (LIF)-elicited conditions. In parallel, VIP-silenced trophoblast cells failed to induce the phagocytosis of apoptotic bodies and the expression of immunosuppressant markers by human monocytes. Our results suggest that VIP-mediated autocrine pathways regulate trophoblast cell function and contribute to immune homeostasis maintenance at placentation and may provide new clues for therapeutic intervention in pregnancies complicated by defective deep placentation. PMID:27212399

  9. The effect of ice-slushy consumption on plasma vasoactive intestinal peptide during prolonged exercise in the heat.

    PubMed

    Burdon, Catriona A; Ruell, Patricia; Johnson, Nathan; Chapman, Phillip; O'Brien, Sinead; O'Connor, Helen T

    2015-01-01

    The aim of this study was to determine the effect of exercise in the heat on thermoregulatory responses and plasma vasoactive intestinal peptide concentration (VIP) and whether it is modulated by ice-slushy consumption. Ten male participants cycled at 62% V̇O2max for 90min in 32°C and 40% relative humidity. A thermoneutral (37°C) or ice-slushy (-1°C) sports drink was given at 3.5mlkg(-1) body mass every 15min during exercise. VIP and rectal temperature increased during exercise (mean±standard deviation: 4.6±4.4pmolL(-1), P=0.005; and 1.3±0.4°C, P<0.001 respectively) and were moderately associated (r=0.35, P=0.008). While rectal temperature and VIP were not different between trials, ice-slushy significantly reduced heat storage (P=0.010) and skin temperature (time×trial interaction P=0.038). It appears that VIP does not provide the signal linking cold beverage ingestion and lower skin temperature in the heat.

  10. Saccharomyces cerevisiae strain UFMG 905 protects against bacterial translocation, preserves gut barrier integrity and stimulates the immune system in a murine intestinal obstruction model.

    PubMed

    Generoso, Simone V; Viana, Mirelle; Santos, Rosana; Martins, Flaviano S; Machado, José A N; Arantes, Rosa M E; Nicoli, Jacques R; Correia, Maria I T D; Cardoso, Valbert N

    2010-06-01

    Probiotic is a preparation containing microorganisms that confers beneficial effect to the host. This work assessed whether oral treatment with viable or heat-killed yeast Saccharomyces cerevisiae strain UFMG 905 prevents bacterial translocation (BT), intestinal barrier integrity, and stimulates the immunity, in a murine intestinal obstruction (IO) model. Four groups of mice were used: mice undergoing only laparotomy (CTL), undergoing intestinal obstruction (IO) and undergoing intestinal obstruction after previous treatment with viable or heat-killed yeast. BT, determined as uptake of (99m)Tc-E. coli in blood, mesenteric lymph nodes, liver, spleen and lungs, was significantly higher in IO group than in CTL group. Treatments with both yeasts reduced BT in blood and all organs investigated. The treatment with both yeasts also reduced intestinal permeability as determined by blood uptake of (99m)Tc-DTPA. Immunological data demonstrated that both treatments were able to significantly increase IL-10 levels, but only viable yeast had the same effect on sIgA levels. Intestinal lesions were more severe in IO group when compared to CTL and yeasts groups. Concluding, both viable and heat-killed cells of yeast prevent BT, probably by immunomodulation and by maintaining gut barrier integrity. Only the stimulation of IgA production seems to depend on the yeast viability.

  11. The Ex Vivo Culture and Pattern Recognition Receptor Stimulation of Mouse Intestinal Organoids.

    PubMed

    Rothschild, Daniel E; Srinivasan, Tara; Aponte-Santiago, Linette A; Shen, Xiling; Allen, Irving C

    2016-05-18

    Primary intestinal organoids are a valuable model system that has the potential to significantly impact the field of mucosal immunology. However, the complexities of the organoid growth characteristics carry significant caveats for the investigator. Specifically, the growth patterns of each individual organoid are highly variable and create a heterogeneous population of epithelial cells in culture. With such caveats, common tissue culture practices cannot be simply applied to the organoid system due to the complexity of the cellular structure. Counting and plating based solely on cell number, which is common for individually separated cells, such as cell lines, is not a reliable method for organoids unless some normalization technique is applied. Normalizing to total protein content is made complex due to the resident protein matrix. These characteristics in terms of cell number, shape and cell type should be taken into consideration when evaluating secreted contents from the organoid mass. This protocol has been generated to outline a simple procedure to culture and treat small intestinal organoids with microbial pathogens and pathogen associated molecular patterns (PAMPs). It also emphasizes the normalization techniques that should be applied when protein analysis are conducted after such a challenge.

  12. Characterization of desmoglein-3 epitope region peptides as synthetic antigens: analysis of their in vitro T cell stimulating efficacy, cytotoxicity, stability, and their conformational features.

    PubMed

    Szabados, Hajnalka; Uray, Katalin; Majer, Zsuzsa; Silló, Pálma; Kárpáti, Sarolta; Hudecz, Ferenc; Bősze, Szilvia

    2015-09-01

    Desmoglein-3 (Dsg3) adhesion protein is the main target of autoantibodies and autoreactive T cells in Pemphigus vulgaris (PV) autoimmune skin disorder. Several mapping studies of Dsg3 T cell epitope regions were performed, and based on those data, we designed and synthesized four peptide series corresponding to Dsg3 T cell epitope regions. Each peptide series consists of a 17mer full-length peptide (Dsg3/189-205, Dsg3/206-222, Dsg3/342-358, and Dsg3/761-777) and its N-terminally truncated derivatives, resulting in 15 peptides altogether. The peptides were prepared on solid phase and were chemically characterized. In order to establish a structure-activity relationship, the solution conformation of the synthetic peptides has been investigated using electronic circular dichroism spectroscopy. The in vitro T cell stimulating efficacy of the peptides has been determined on peripheral blood mononuclear cells isolated from whole blood of PV patients and also from healthy donors. After 20 h of stimulation, the interferon (IFN)-γ content of the supernatants was measured by enzyme-linked immunosorbent assay. In the in vitro conditions, peptides were stable and non-cytotoxic. The in vitro IFN-γ production profile of healthy donors and PV patients, induced by peptides as synthetic antigens, was markedly different. The most unambiguous differences were observed after stimulation with 17mer peptide Dsg3/342-358, and three truncated derivatives from two other peptide series, namely, peptides Dsg3/192-205, Dsg3/763-777, and Dsg3/764-777. Comparative analysis of in vitro activity and the capability of oligopeptides to form ordered or unordered secondary structure showed that peptides bearing high solvent sensibility and backbone flexibility were the most capable to distinguish between healthy and PV donors.

  13. An Arg-Gly-Asp peptide stimulates Ca2+ efflux from osteoclast precursors through a novel mechanism

    NASA Technical Reports Server (NTRS)

    Yamakawa, K.; Duncan, R.; Hruska, K. A.

    1994-01-01

    We examined the effect of a peptide containing the Arg-Gly-Asp (RGD) sequence on 45Ca2+ efflux from osteoclast precursors. 45Ca(2+)-loaded osteoclast precursors were treated with GRGDSP (170 microM) for 10 min after 30 min of basal perfusion with a bicarbonate-containing buffer. GRGDSP significantly increased fractional efflux of Ca2+ from treated cells compared with vehicle-treated cells (P < 0.01) or cells treated with up to 200 micrograms/ml of a control peptide containing GRGESP. The effect of RGD was sustained for 15 min after the peptide was removed from the perfusate, but control levels of Ca2+ efflux returned by 1 h. The Ca2+ efflux effect of GRGDSP was most likely due to activation of the plasma membrane Ca(2+)-adenosinetriphosphatase (Ca(2+)-ATPase) pump, as indicated by its inhibition with vanadate and a calmodulin antagonist, N-(4-aminobutyl)-5-chloro-2-naphthalenesulfonamide, and the absence of an effect of Na+/Ca2+ exchange inhibition. An inhibitor of cyclic nucleotide-dependent protein kinases, N-[2-(methylamino)ethyl]-5-isoquinoline-sulfonamide (0.1 mM), failed to inhibit GRGDSP-stimulated Ca2+ efflux. However, genistein and herbimycin A, inhibitors of protein-tyrosine kinases, blocked Ca2+ efflux stimulated by GRGDSP. The results indicate that RGD sequences of matrix proteins may stimulate Ca2+ efflux from osteoclasts through activation of protein-tyrosine kinases and suggest that GRGDSP-stimulated Ca2+ efflux is mediated via the plasma membrane Ca(2+)-ATPase.

  14. Acarbose, lente carbohydrate, and prebiotics promote metabolic health and longevity by stimulating intestinal production of GLP-1

    PubMed Central

    McCarty, Mark F; DiNicolantonio, James J

    2015-01-01

    The α-glucosidase inhibitor acarbose, which slows carbohydrate digestion and blunts postprandial rises in plasma glucose, has long been used to treat patients with type 2 diabetes or glucose intolerance. Like metformin, acarbose tends to aid weight control, postpone onset of diabetes and decrease risk for cardiovascular events. Acarbose treatment can favourably affect blood pressure, serum lipids, platelet aggregation, progression of carotid intima-media thickness and postprandial endothelial dysfunction. In mice, lifetime acarbose feeding can increase median and maximal lifespan—an effect associated with increased plasma levels of fibroblast growth factor 21 (FGF21) and decreased levels of insulin-like growth factor-I (IGF-I). There is growing reason to suspect that an upregulation of fasting and postprandial production of glucagon-like peptide-1 (GLP-1)—stemming from increased delivery of carbohydrate to L cells in the distal intestinal tract—is largely responsible for the versatile health protection conferred by acarbose. Indeed, GLP-1 exerts protective effects on vascular endothelium, the liver, the heart, pancreatic β cells, and the brain which can rationalise many of the benefits reported with acarbose. And GLP-1 may act on the liver to modulate its production of FGF21 and IGF-I, thereby promoting longevity. The benefits of acarbose are likely mimicked by diets featuring slowly-digested ‘lente’ carbohydrate, and by certain nutraceuticals which can slow carbohydrate absorption. Prebiotics that promote colonic generation of short-chain fatty acids represent an alternative strategy for boosting intestinal GLP-1 production. The health benefits of all these measures presumably would be potentiated by concurrent use of dipeptidyl peptidase 4 inhibitors, which slow the proteolysis of GLP-1 in the blood. PMID:25685364

  15. Fine-tuning the stimulation of MLL1 methyltransferase activity by a histone H3-based peptide mimetic

    SciTech Connect

    Avdic, Vanja; Zhang, Pamela; Lanouette, Sylvain; Voronova, Anastassia; Skerjanc, Ilona; Couture, Jean-Francois

    2011-08-24

    The SET1 family of methyltransferases carries out the bulk of histone H3 Lys-4 methylation in vivo. One of the common features of this family is the regulation of their methyltransferase activity by a tripartite complex composed of WDR5, RbBP5, and Ash2L. To selectively probe the role of the SET1 family of methyltransferases, we have developed a library of histone H3 peptide mimetics and report herein the characterization of an N{alpha} acetylated form of histone H3 peptide (N{alpha}H3). Binding and inhibition studies reveal that the addition of an acetyl moiety to the N terminus of histone H3 significantly enhances its binding to WDR5 and prevents the stimulation of MLL1 methyltransferase activity by the WDR5-RbBP5-Ash2L complex. The crystal structure of N{alpha}H3 in complex with WDR5 reveals that a high-affinity hydrophobic pocket accommodates the binding of the acetyl moiety. These results provide the structural basis to control WDR5-RbBP5-Ash2L-MLL1 activity and a tool to manipulate stem cell differentiation programs.-Avdic, V., Zhang, P., Lanouette, S., Voronova, A., Skerjanc, I., Couture, J.-F. Fine-tuning the stimulation of MLL1 methyltransferase activity by a histone H3-based peptide mimetic.

  16. Oral peptide specific egg antibody to intestinal sodium-dependent phosphate co-transporter-2b is effective at altering phosphate transport in vitro and in vivo.

    PubMed

    Bobeck, Elizabeth A; Hellestad, Erica M; Sand, Jordan M; Piccione, Michelle L; Bishop, Jeff W; Helvig, Christian; Petkovich, Martin; Cook, Mark E

    2015-06-01

    Hyperimmunized hens are an effective means of generating large quantities of antigen specific egg antibodies that have use as oral supplements. In this study, we attempted to create a peptide specific antibody that produced outcomes similar to those of the human pharmaceutical, sevelamer HCl, used in the treatment of hyperphosphatemia (a sequela of chronic renal disease). Egg antibodies were generated against 8 different human intestinal sodium-dependent phosphate cotransporter 2b (NaPi2b) peptides, and hNaPi2b peptide egg antibodies were screened for their ability to inhibit phosphate transport in human intestinal Caco-2 cell line. Antibody produced against human peptide sequence TSPSLCWT (anti-h16) was specific for its peptide sequence, and significantly reduced phosphate transport in human Caco-2 cells to 25.3±11.5% of control nonspecific antibody, when compared to nicotinamide, a known inhibitor of phosphate transport (P≤0.05). Antibody was then produced against the mouse-specific peptide h16 counterpart (mouse sequence TSPSYCWT, anti-m16) for further analysis in a murine model. When anti-m16 was fed to mice (1% of diet as dried egg yolk powder), egg yolk immunoglobulin (IgY) was detected using immunohistochemical staining in mouse ileum, and egg anti-m16 IgY colocalized with a commercial goat anti-NaPi2b antibody. The effectiveness of anti-m16 egg antibody in reducing serum phosphate, when compared to sevelamer HCl, was determined in a mouse feeding study. Serum phosphate was reduced 18% (P<0.02) in mice fed anti-m16 (1% as dried egg yolk powder) and 30% (P<0.0001) in mice fed sevelamer HCl (1% of diet) when compared to mice fed nonspecific egg immunoglobulin. The methods described and the findings reported show that oral egg antibodies are useful and easy to prepare reagents for the study and possible treatment of select diseases.

  17. Expression of cholecystokinin2-receptor in rat and human L cells and the stimulation of glucagon-like peptide-1 secretion by gastrin treatment.

    PubMed

    Cao, Yang; Cao, Xun; Liu, Xiao-Min

    2015-03-01

    Gastrin is a gastrointestinal hormone secreted by G cells. Hypergastrinemia can improve blood glucose and glycosylated hemoglobin levels. These positive effects are primarily due to the trophic effects of gastrin on β-cells. In recent years, many receptors that regulate secretion of glucagon-like peptide 1 (GLP-1) have been identified in enteroendocrine L cell lines. This led us to hypothesize that, in addition to the trophic effects of gastrin on β-cells, L cells also express cholecystokinin2-receptor (CCK2R), which may regulate GLP-1 secretion and have synergistic effects on glucose homeostasis. Our research provides a preliminary analysis of CCK2R expression and the stimulating effect of gastrin treatment on GLP-1 secretion in a human endocrine L cell line, using RT-PCR, Western blot, immunocytochemistry, and ELISA analyses. The expression of proglucagon and prohormone convertase 3, which regulate GLP-1 biosynthesis, were also analyzed by real-time PCR. Double immunofluorescence labeling was utilized to assess the intracellular localization of CCK2R and GLP-1 in L cells harvested from rat colon tissue. Our results showed that CCK2R was expressed in both the human L cell line and the rat L cells. We also showed that treatment with gastrin, a CCK2R agonist, stimulated the secretion of GLP-1, and that this effect was likely due to increased expression of proglucagon and PCSK1 (also known as prohormone convertase 3 (PC3 gene)). These results not only provide a basis for the role gastrin may play in intestinal L cells, and may also provide the basis for the development of a method of gastrin-mediated glycemic regulation.

  18. Relationship between stimulated phosphatidic acid production and inositol lipid hydrolysis in intestinal longitudinal smooth muscle from guinea pig.

    PubMed

    Mallows, R S; Bolton, T B

    1987-06-15

    Accumulation of [32P]phosphatidic acid (PA) and total [3H]inositol phosphates (IPs) was measured in the longitudinal smooth-muscle layer from guinea-pig small intestine. Stimulation with carbachol, histamine and substance P produced increases in accumulation of both [3H]IPs and [32P]PA over the same concentration range. The increase in [32P]PA accumulation in response to carbachol (1 microM-0.1 mM) was inhibited in the presence of atropine (0.5 microM). Buffering the external free [Ca2+] to 10 nM did not prevent the carbachol-stimulated increase in [32P]PA accumulation. Carbachol and Ca2+ appear to act synergistically to increase accumulation of [32P]PA. In contrast, although incubation with noradrenaline also increased accumulation of [3H]IPs, no increase in accumulation of [32P]PA could be detected. These results suggest that an increase in formation of IPs is not necessarily accompanied by an increase in PA formation, and imply the existence of receptor-modulated pathways regulating PA concentrations other than by phospholipase-C-catalysed inositol phospholipid hydrolysis.

  19. Melanoma Therapy with Rhenium-Cyclized Alpha Melanocyte Stimulating Hormone Peptide Analogs

    SciTech Connect

    Thomas P Quinn

    2005-11-22

    Malignant melanoma is the 6th most commonly diagnosed cancer with increasing incidence in the United States. It is estimated that 54,200 cases of malignant melanoma will be newly diagnosed and 7,600 cases of death will occur in the United States in the year 2003 (1). At the present time, more than 1.3% of Americans will develop malignant melanoma during their lifetime (2). The average survival for patients with metastatic melanoma is about 6-9 months (3). Moreover, metastatic melanoma deposits are resistant to conventional chemotherapy and external beam radiation therapy (3). Systematic chemotherapy is the primary therapeutic approach to treat patients with metastatic melanoma. Dacarbazine is the only single chemotherapy agent approved by FDA for metastatic melanoma treatment (5). However, the response rate to Dacarbazine is only approximately 20% (6). Therefore, there is a great need to develop novel treatment approaches for metastatic melanoma. The global goal of this research program is the rational design, characterization and validation of melanoma imaging and therapeutic radiopharmaceuticals. Significant progress has been made in the design and characterization of metal-cyclized radiolabeled alpha-melanocyte stimulating hormone peptides. Therapy studies with {sup 188}Re-CCMSH demonstrated the therapeutic efficacy of the receptor-targeted treatment in murine and human melanoma bearing mice (previous progress report). Dosimetry calculations, based on biodistribution data, indicated that a significant dose was delivered to the tumor. However, {sup 188}Re is a very energetic beta-particle emitter. The longer-range beta-particles theoretically would be better for larger tumors. In the treatment of melanoma, the larger primary tumor is usually surgically removed leaving metastatic disease as the focus of targeted radiotherapy. Isotopes with lower beta-energies and/or shorter particle lengths should be better suited for targeting metastases. The {sup 177}Lu

  20. Nutrient-intake-level-dependent regulation of intestinal development in newborn intrauterine growth-restricted piglets via glucagon-like peptide-2.

    PubMed

    Liu, J; Liu, Z; Gao, L; Chen, L; Zhang, H

    2016-10-01

    The objective of the present study was to investigate the intestinal development of newborn intrauterine growth-restricted (IUGR) piglets subjected to normal nutrient intake (NNI) or restricted nutrient intake (RNI). Newborn normal birth weight (NBW) and IUGR piglets were allotted to NNI or RNI levels for 4 weeks from day 8 postnatal. IUGR piglets receiving NNI had similar growth performance compared with that of NBW piglets. Small intestine length and villous height were greater in IUGR piglets fed the NNI than that of piglets fed the RNI. Lactase activity was increased in piglets fed the NNI compared with piglets fed the RNI. Absorptive function, represented by active glucose transport by the Ussing chamber method and messenger RNA (mRNA) expressions of two main intestinal glucose transporters, Na+-dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2), were greater in IUGR piglets fed the NNI compared with piglets fed the RNI regimen. The apoptotic process, characterized by caspase-3 activity (a sign of activated apoptotic cells) and mRNA expressions of p53 (pro-apoptotic), bcl-2-like protein 4 (Bax) (pro-apoptotic) and B-cell lymphoma-2 (Bcl-2) (anti-apoptotic), were improved in IUGR piglets fed the NNI regimen. To test the hypothesis that improvements in intestinal development of IUGR piglets fed NNI might be mediated through circulating glucagon-like peptide-2 (GLP-2), GLP-2 was injected subcutaneously to IUGR piglets fed the RNI from day 8 to day 15 postnatal. Although the intestinal development of IUGR piglets fed the RNI regimen was suppressed compared with those fed the NNI regimen, an exogenous injection of GLP-2 was able to bring intestinal development to similar levels as NNI-fed IUGR piglets. Collectively, our results demonstrate that IUGR neonates that have NNI levels could improve intestinal function via the regulation of GLP-2.

  1. Purification and identification of a growth-stimulating peptide for Bifidobacterium bifidum from natural rubber serum powder.

    PubMed

    Etoh, S; Asamura, K; Obu, A; Sonomoto, K; Ishizaki, A

    2000-10-01

    Natural rubber serum powder, which is a by-product obtained in the production of latex rubber, has a strong growth-stimulating activity for Bifidobacterium bifidum JCM 1254. The retained fraction obtained by ultrafiltration (molecular weight cutoff 1000) showed a growth-stimulating activity in a dose-dependent manner on B12 assay medium with ammonium sulfate. One of the growth stimulators was purified from the retained fraction by acetone precipitation, solid-phase extraction with a hydrophobic pretreatment column, and multistage reversed-phase HPLC. An increase of 53-fold in the specific activity, and a recovery of 1.3% were obtained. The amino acid composition and N-terminal sequence analysis of this growth stimulator provided the structure of Ala-Thr-Pro-Glu-Lys-Glu-Glu-Pro-Thr-Ala. The molecular mass was 1075 by MALDI-TOF MS analysis. These results showed that this growth stimulator was a decapeptide with the sequence shown above. This is the first report that clarified the structure of an active peptide for the growth of Bifidobacterium.

  2. Bile acid-regulated peroxisome proliferator-activated receptor-α (PPARα) activity underlies circadian expression of intestinal peptide absorption transporter PepT1/Slc15a1.

    PubMed

    Okamura, Ayako; Koyanagi, Satoru; Dilxiat, Adila; Kusunose, Naoki; Chen, Jia Jun; Matsunaga, Naoya; Shibata, Shigenobu; Ohdo, Shigehiro

    2014-09-05

    Digested proteins are mainly absorbed as small peptides composed of two or three amino acids. The intestinal absorption of small peptides is mediated via only one transport system: the proton-coupled peptide transporter-1 (PepT1) encoded from the soluble carrier protein Slc15a1. In mammals, intestinal expression of PepT1/Slc15a1 oscillates during the daily feeding cycle. Although the oscillation in the intestinal expression of PepT1/Slc15a1 is suggested to be controlled by molecular components of circadian clock, we demonstrated here that bile acids regulated the oscillation of PepT1/Slc15a1 expression through modulating the activity of peroxisome proliferator-activated receptor α (PPARα). Nocturnally active mice mainly consumed their food during the dark phase. PPARα activated the intestinal expression of Slc15a1 mRNA during the light period, and protein levels of PepT1 peaked before the start of the dark phase. After food intake, bile acids accumulated in intestinal epithelial cells. Intestinal accumulated bile acids interfered with recruitment of co-transcriptional activator CREB-binding protein/p300 on the promoter region of Slc15a1 gene, thereby suppressing PPARα-mediated transactivation of Slc15a1. The time-dependent suppression of PPARα-mediated transactivation by bile acids caused an oscillation in the intestinal expression of PepT1/Slc15a1 during the daily feeding cycle that led to circadian changes in the intestinal absorption of small peptides. These findings suggest a molecular clock-independent mechanism by which bile acid-regulated PPARα activity governs the circadian expression of intestinal peptide transporter.

  3. Stimulation of glucagon-like peptide-1 secretion downstream of the ligand-gated ion channel TRPA1

    PubMed Central

    Emery, Edward C.; Diakogiannaki, Eleftheria; Gentry, Clive; Psichas, Arianna; Habib, Abdella M.; Bevan, Stuart; Fischer, Michael J. M.; Reimann, Frank; Gribble, Fiona M.

    2015-01-01

    Stimulus-coupled incretin secretion from enteroendocrine cells plays a fundamental role in glucose homeostasis, and could be targeted for the treatment of type-2 diabetes. Here, we investigated the expression and function of transient receptor potential (TRP) ion channels in enteroendocrine L-cells producing glucagon-like peptide-1 (GLP-1). By microarray and qPCR analysis we identified trpa1 as an L-cell enriched transcript in the small intestine. Calcium imaging of primary L-cells and the model cell line GLUTag revealed responses triggered by the TRPA1 agonists allyl-isothiocyanate (AITC, mustard oil), carvacrol and polyunsaturated fatty acids, that were blocked by TRPA1 antagonists. Electrophysiology in GLUTag cells showed that carvacrol induced a current with characteristics typical of TRPA1 and triggered the firing of action potentials. TRPA1 activation caused an increase in GLP-1 secretion from primary murine intestinal cultures and GLUTag cells; an effect that was abolished in cultures from trpa1−/− mice or by pharmacological TRPA1 inhibition. These findings present TRPA1 as a novel sensory mechanism in enteroendocrine L-cells, coupled to the facilitation of GLP-1 release, which may be exploitable as a target for treating diabetes. PMID:25325736

  4. A new model of reverse cholesterol transport: enTICEing strategies to stimulate intestinal cholesterol excretion.

    PubMed

    Temel, Ryan E; Brown, J Mark

    2015-07-01

    Cardiovascular disease (CVD) remains the largest cause of mortality in most developed countries. Although recent failed clinical trials and Mendelian randomization studies have called into question the high-density lipoprotein (HDL) hypothesis, it remains well accepted that stimulating the process of reverse cholesterol transport (RCT) can prevent or even regress atherosclerosis. The prevailing model for RCT is that cholesterol from the artery wall must be delivered to the liver where it is secreted into bile before leaving the body through fecal excretion. However, many studies have demonstrated that RCT can proceed through a non-biliary pathway known as transintestinal cholesterol excretion (TICE). The goal of this review is to discuss the current state of knowledge of the TICE pathway, with emphasis on points of therapeutic intervention.

  5. Brain Natriuretic Peptide Stimulates Lipid Metabolism through Its Receptor NPR1 and the Glycerolipid Metabolism Pathway in Chicken Adipocytes.

    PubMed

    Huang, H Y; Zhao, G P; Liu, R R; Li, Q H; Zheng, M Q; Li, S F; Liang, Z; Zhao, Z H; Wen, J

    2015-11-03

    Brain natriuretic peptide (BNP) is related to lipid metabolism in mammals, but its effect and the molecular mechanisms underlying it in chickens are incompletely understood. We found that the level of natriuretic peptide precursor B (NPPB, which encodes BNP) mRNA expression in high-abdominal-fat chicken groups was significantly higher than that of low-abdominal-fat groups. Partial correlations indicated that changes in the weight of abdominal fat were positively correlated with NPPB mRNA expression level. In vitro, compared with the control group, preadipocytes with NPPB interference showed reduced levels of proliferation, differentiation, and glycerin in media. Treatments of cells with BNP led to enhanced proliferation and differentiation of cells and glycerin concentration, and mRNA expression of its receptor natriuretic peptide receptor 1 (NPR1) was upregulated significantly. In cells exposed to BNP, 482 differentially expressed genes were identified compared with controls without BNP. Four genes known to be related to lipid metabolism (diacylglycerol kinase; lipase, endothelial; 1-acylglycerol-3-phosphate O-acyltransferase 1; and 1-acylglycerol-3-phosphate O-acyltransferase 2) were enriched in the glycerolipid metabolism pathway and expressed differentially. In conclusion, BNP stimulates the proliferation, differentiation, and lipolysis of preadipocytes through upregulation of the levels of expression of its receptor NPR1 and key genes enriched in the glycerolipid metabolic pathway.

  6. A Nascent Peptide Signal Responsive to Endogenous Levels of Polyamines Acts to Stimulate Regulatory Frameshifting on Antizyme mRNA.

    PubMed

    Yordanova, Martina M; Wu, Cheng; Andreev, Dmitry E; Sachs, Matthew S; Atkins, John F

    2015-07-17

    The protein antizyme is a negative regulator of cellular polyamine concentrations from yeast to mammals. Synthesis of functional antizyme requires programmed +1 ribosomal frameshifting at the 3' end of the first of two partially overlapping ORFs. The frameshift is the sensor and effector in an autoregulatory circuit. Except for Saccharomyces cerevisiae antizyme mRNA, the frameshift site alone only supports low levels of frameshifting. The high levels usually observed depend on the presence of cis-acting stimulatory elements located 5' and 3' of the frameshift site. Antizyme genes from different evolutionary branches have evolved different stimulatory elements. Prior and new multiple alignments of fungal antizyme mRNA sequences from the Agaricomycetes class of Basidiomycota show a distinct pattern of conservation 5' of the frameshift site consistent with a function at the amino acid level. As shown here when tested in Schizosaccharomyces pombe and mammalian HEK293T cells, the 5' part of this conserved sequence acts at the nascent peptide level to stimulate the frameshifting, without involving stalling detectable by toe-printing. However, the peptide is only part of the signal. The 3' part of the stimulator functions largely independently and acts at least mostly at the nucleotide level. When polyamine levels were varied, the stimulatory effect was seen to be especially responsive in the endogenous polyamine concentration range, and this effect may be more general. A conserved RNA secondary structure 3' of the frameshift site has weaker stimulatory and polyamine sensitizing effects on frameshifting.

  7. A method for identification of the peptides that bind to a clone of thyroid-stimulating antibodies in the serum of Graves' disease patients.

    PubMed

    Na, Chan Hyun; Lee, Mi Hwa; Cho, Bo Youn; Chae, Chi-Bom

    2003-04-01

    A method was developed for identification of the peptide sequences that bind to thyroid-stimulating antibody (TSAb) clones from phage-displayed peptide library. Immunoglobulin G (IgG) was purified from the serum of a Graves' disease patient that stimulates the synthesis of cAMP in the cells that express TSH receptor (TSHR). The IgG that binds to TSHR was purified by an affinity column packed with the resin cross-linked with the extracellular domain of human TSHR. The receptor-binding IgG was then mixed with phages that display linear or cyclic peptides at the end of tail protein pIII. The bound phages were eluted with acidic glycine after extensive washing. From sequencing of the pIII gene of the bound phages, one can deduce the sequences of the peptides that bind to the receptor-binding IgG. Each peptide sequence was then tested for inhibition of the synthesis of cAMP from thyroid cells induced by the serum of a Graves' patient. In this way, one can obtain the peptides that bind to a clone of TSAb. We obtained a peptide sequence that inhibits the action of TSAb at an extremely low concentration (<10(-14) M). Such a peptide will be useful for various studies on TSAb.

  8. Cell adhesive peptides functionalized on CoCr alloy stimulate endothelialization and prevent thrombogenesis and restenosis.

    PubMed

    Castellanos, Maria Isabel; Guillem-Marti, Jordi; Mas-Moruno, Carlos; Díaz-Ricart, Maribel; Escolar, Ginés; Ginebra, Maria Pau; Gil, Francisco Javier; Pegueroles, Marta; Manero, Jose María

    2017-04-01

    Immobilization of bioactive peptide sequences on CoCr surfaces is an effective route to improve endothelialization, which is of great interest for cardiovascular stents. In this work, we explored the effect of physical and covalent immoblization of RGDS, YIGSR and their equimolar combination peptides on endothelial cells (EC) and smooth muscle cell (SMC) adhesion and on thrombogenicity. We extensively investigated using RT-qPCR, the expression by ECs cultured on functionalised CoCr surfaces of different genes. Genes relevant for adhesion (ICAM-1 and VCAM-1), vascularization (VEGFA, VEGFR-1 and VEGFR-2) and anti-thrombogenicity (tPA and eNOS) were over-expressed in the ECs grown to covalently functionalized CoCr surfaces compared to physisorbed and control surfaces. Pro-thrombogenic genes expression (PAI-1 and vWF) decreased over time. Cell co-cultures of ECs/SMCs found that functionalization increased the amount of adhered ECs onto modified surfaces compared to plain CoCr, independently of the used peptide and the strategy of immobilization. SMCs adhered less compared to ECs in all surfaces. All studied peptides showed a lower platelet cell adhesion compared to TCPS. Covalent functionalization of CoCr surfaces with an equimolar combination of RGDS and YIGSR represented prevailing strategy to enhance the early stages of ECs adhesion and proliferation, while preventing SMCs and platelet adhesion. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 973-983, 2017.

  9. Vasoactive intestinal peptide induces CD14+HLA-DR‑/low myeloid-derived suppressor cells in gastric cancer.

    PubMed

    Li, Gang; Wu, Ke; Tao, Kaixiong; Lu, Xiaoming; Ma, Jianhua; Mao, Zhengqiang; Li, Hang; Shi, Liang; Li, Jing; Niu, Yanfeng; Xiang, Fan; Wang, Guobin

    2015-07-01

    Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of cells, which have been revealed to inhibit T-cell responses in tumor-bearing mice. In addition, a number of immune suppressive mechanisms have linked MDSCs and the development of human cancer. However, the role of MDSCs in human gastric cancer tissue remains to be elucidated as specific markers are lacking. Therefore, the aim of the present study was to investigate the frequency and immune suppressive function of MDSCs denoted in the present study as cluster of differentiation 14 (CD14)+human leukocyte antigen (HLA)-DR-/low in gastric cancer patients. In the present study, MDSCs were directly isolated and characterized from the tumor and adjacent normal tissue of gastric cancer patients. Functional analysis of the CD14+HLA-DR-/low MDSCs co-cultured with allogeneic CD4+ T cells were performed and compared with controls. In addition, the interferon-γ (IFN-γ) and interleukin (IL)-2 production was compared in order to investigate the capacity of vasoactive intestinal peptide (VIP) to induce CD14+HLA-DR(-/low) MDSC-mediated CD4+ T-cell dysfunction and whether IL-10 secretion is involved in this mechanism. As a result, the quantity of CD14+HLA-DR(-/low) cells in tumor tissue from gastric cancer patients was significantly higher than that in the adjacent normal tissue. In addition, CD14+HLA-DR-/low MDSCs isolated from tumor tissue were observed to inhibit the CD4+ T-cells' immune responses in comparison with those from the adjacent normal tissue. Furthermore, VIP was able to induce the differentiation of CD14+ mononuclear cells isolated from healthy donor peripheral blood mononuclear cells into activated MDSC cells. Of note, the immunosuppressive effect of VIP-induced CD14+HLA-DR(-/low) MDSCs on CD4+ T cells was mediated by IL-10 secretion, which was demonstrated in the subsequent decrease of IFN-γ and IL-2 production. In conclusion, CD14+HLA-DR(-/low) cells were significantly increased in gastric

  10. Hypergravity differentially modulates cGMP efflux in human melanocytic cells stimulated by nitric oxide and natriuretic peptides

    NASA Astrophysics Data System (ADS)

    Ivanova, K.; Stieber, C.; Lambers, B.; Block, I.; Krieg, R.; Wellmann, A.; Gerzer, R.

    Nitric oxide NO plays a key role in many patho physiologic processes including inflammation and skin cancer The diverse cellular effects of NO are mainly mediated by activation of the soluble guanylyl cyclase sGC isoform that leads to increases in intracellular cGMP levels whereas the membrane-bound isoforms serve as receptors for natriuretic peptides e g ANP In human skin epidermal melanocytes represent the principal cells for skin pigmentation by synthesizing the pigment melanin Melanin acts as a scavenger for free radicals that may arise during metabolic stress as a result of potentially harmful effects of the environment In previous studies we found that long-term exposure to hypergravity stimulated cGMP efflux in normal human melanocytes NHMs and non-metastatic melanoma cells at least partly by an enhanced expression of the multidrug resistance proteins MRP and cGMP transporters MRP4 5 The present study investigated whether hypergravity generated by centrifugal acceleration may modulate the cGMP efflux in NO-stimulated NHMs and melanoma cells MCs with different metastatic potential The NONOates PAPA-NO and DETA-NO were used as direct NO donors for cell stimulation In the presence of 0 1 mM DETA-NO t 1 2 sim 20 h long-term application of hypergravity up to 5 g for 24 h reduced intracellular cGMP levels by stimulating cGMP efflux in NHMs and non-metastatic MCs in comparison to 1 g whereas exposure to 5 g for 6 h in the presence of 0 1 mM PAPA-NO t 1 2 sim 30 min was not effective The hypergravity-stimulated

  11. Repetitive Arg-Gly-Asp peptide as a cell-stimulating agent on electrospun poly(ϵ-caprolactone) scaffold for tissue engineering.

    PubMed

    Chaisri, Pacharaporn; Chingsungnoen, Artit; Siri, Sineenat

    2013-11-01

    Electrospun scaffolds derived from poly(ϵ-caprolactone) (PCL), a well known biodegradable material, have an architecture that is suitable for hosting cells. However, their biomedical applications are restricted because these scaffolds lack the bioactivity necessary to stimulate cell responses. In this work, a repetitive Arg-Gly-Asp (rRGD) peptide was produced as a cell-stimulating agent to provide the PCL scaffold with bioactivity. DNA encoding rRGD was amplified by polymerase chain reaction using overlap primers without a DNA template, and cloned into a protein expression vector to produce a His-tag fusion peptide. In an in vitro cell adhesion assay, the purified rRGD peptide, comprising 30 RGD repeats, promoted a 1.5-fold greater cell adhesion than the commercial tripeptide RGD. The rRGD peptide was immobilized onto an electrospun PCL scaffold that had been pretreated with argon plasma and graft-polymerized with acrylic acid. Fourier transform infrared (FTIR) analysis indicated that covalently linked rRGD peptide was present on the scaffold. The PCL scaffold with immobilized rRGD showed significantly changed hydrophilic properties and an enhanced adhesion and proliferation of mouse fibroblast cells by 2.3- and 2.9-fold, respectively, compared to the PCL scaffold alone. Through its ability to promote cell adhesion and proliferation, the rRGD peptide has great potential as a stimulant for improving the suboptimal cell-matrix interaction of polymeric scaffolds for tissue engineering applications.

  12. Vasoactive intestinal peptide test

    MedlinePlus

    ... the pancreas, gut, and hypothalamus, and increasing the amount of water and electrolytes secreted from the pancreas and gut. VIPomas produce and release VIP into the blood. This blood test checks the amount of VIP in the blood to see if ...

  13. Extracellular Life Cycle of ComS, the Competence-Stimulating Peptide of Streptococcus thermophilus

    PubMed Central

    Besset, Colette; Gitton, Christophe; Guillot, Alain; Fontaine, Laetitia; Hols, Pascal; Monnet, Véronique

    2013-01-01

    In streptococci, ComX is the alternative sigma factor controlling the transcription of the genes encoding the genetic transformation machinery. In Streptococcus thermophilus, comX transcription is controlled by a complex consisting of a transcriptional regulator of the Rgg family, ComR, and a signaling peptide, ComS, which controls ComR activity. Following its initial production, ComS is processed, secreted, and imported back into the cell by the Ami oligopeptide transporter. We characterized these steps and the partners interacting with ComS during its extracellular circuit in more detail. We identified the mature form of ComS and demonstrated the involvement of the membrane protease Eep in ComS processing. We found that ComS was secreted but probably not released into the extracellular medium. Natural competence was first discovered in a chemically defined medium without peptides. We show here that the presence of a high concentration of nutritional peptides in the medium prevents the triggering of competence. In milk, the ecological niche of S. thermophilus, competence was found to be functional, suggesting that the concentration of nutritional peptides was too low to interfere with ComR activation. The kinetics of expression of the comS, comR, and comX genes and of a late competence gene, dprA, in cultures inoculated at different initial densities revealed that the activation mechanism of ComR by ComS is more a timing device than a quorum-sensing mechanism sensu stricto. We concluded that the ComS extracellular circuit facilitates tight control over the triggering of competence in S. thermophilus. PMID:23396911

  14. Diet-Derived Short Chain Fatty Acids Stimulate Intestinal Epithelial Cells To Induce Mucosal Tolerogenic Dendritic Cells.

    PubMed

    Goverse, Gera; Molenaar, Rosalie; Macia, Laurence; Tan, Jian; Erkelens, Martje N; Konijn, Tanja; Knippenberg, Marlene; Cook, Emma C L; Hanekamp, Diana; Veldhoen, Marc; Hartog, Anita; Roeselers, Guus; Mackay, Charles R; Mebius, Reina E

    2017-03-01

    The gastrointestinal tract is continuously exposed to many environmental factors that influence intestinal epithelial cells and the underlying mucosal immune system. In this article, we demonstrate that dietary fiber and short chain fatty acids (SCFAs) induced the expression of the vitamin A-converting enzyme RALDH1 in intestinal epithelial cells in vivo and in vitro, respectively. Furthermore, our data showed that the expression levels of RALDH1 in small intestinal epithelial cells correlated with the activity of vitamin A-converting enzymes in mesenteric lymph node dendritic cells, along with increased numbers of intestinal regulatory T cells and a higher production of luminal IgA. Moreover, we show that the consumption of dietary fiber can alter the composition of SCFA-producing microbiota and SCFA production in the small intestines. In conclusion, our data illustrate that dietary adjustments affect small intestinal epithelial cells and can be used to modulate the mucosal immune system.

  15. Glucagon-like peptide-2 reduces intestinal permeability but does not modify the onset of type 1 diabetes in the nonobese diabetic mouse.

    PubMed

    Hadjiyanni, Irene; Li, Kunmin Karen; Drucker, Daniel J

    2009-02-01

    The development of type 1 diabetes (T1D) has been linked to environmental factors and dietary components. Increasing evidence indicates that the integrity of the gut mucosa plays a role in the development of autoimmune diseases, and evidence from both preclinical and clinical studies demonstrates that increased leakiness of the intestinal epithelium precedes the development of type 1 diabetes. However, there is limited information on modulation of gut barrier function and its relationship to diabetes development. Here we show that the nonobese diabetic (NOD) mouse, a model of T1D, exhibits enhanced intestinal transcellular permeability before the development of autoimmune diabetes. Treatment of NOD mice with a glucagon-like peptide 2 (GLP-2) analog, synthetic human [Gly(2)] glucagon-like peptide-2 (h[Gly(2)]GLP-2, increased the length and weight of the small bowel and significantly improved jejunal transepithelial resistance. However, chronic administration of once daily h[Gly(2)]GLP-2 failed to delay or reverse the onset of T1D when treatment was initiated in young, normoglycemic female NOD mice. Furthermore, h[Gly(2)]GLP-2 administration had no significant effect on lymphocyte subpopulations in NOD mice. These findings demonstrate that h[Gly(2)]GLP-2-mediated enhancement of gut barrier function in normoglycemic NOD mice disease is not sufficient to prevent or delay the development of experimental T1D.

  16. Radioimmunoassay determination of tachykinin-related peptide in different portions of the central nervous system and intestine of the cockroach Leucophaea maderae.

    PubMed

    Muren, J E; Nässel, D R

    1996-11-11

    A radioimmunoassay was developed for insect tachykinin-related peptides with the use of an antiserum raised to the locust neuropeptide locustatachykinin I (LomTK I). Determination of tachykinin-related peptide was performed in different tissues of the cockroach Leucophaea maderae. The largest amounts of LomTK-like immunoreactivity (LomTK-LI) reside in the brain and in the midgut. Relatively large amounts were also found in the suboesophageal ganglion and throughout the ganglia of the ventral nerve cord, whereas smaller amounts of LomTK-LI were detected in the corpora cardiaca, foregut and hindgut. Extracts of unfused abdominal ganglia and midguts, respectively, were analysed by a combination of reversed phase high performance liquid chromatography, and radioimmunoassay for LomTK-LI. The extracts of abdominal ganglia and midguts both contain LomTK-LI material which separates in at least two major components. This LomTK-LI material had retention times corresponding approximately to those of synthetic LomTK I and II. Since the cellular source of LomTK-LI material in the foregut and hindgut was not known from earlier studies, we investigated these tissues by immunocytochemistry. We found that the LomTK-LI material associated with the foregut was in arborizing fibres in the oesophageal and gastric nerves and in the ingluvial ganglion. In the hindgut the muscle layer was innervated by immunoreactive fibres derived from cell bodies in the terminal ganglion. The amount of LomTK-LI material in other portions of the nervous system correlates well with previous immunocytochemical data. We conclude that L. maderae have two or more isoforms of tachykinin-related peptides in the nervous system and intestine and that these are present in various amounts in different parts of the central nervous system and intestine. The relative large amounts of LomTK-LI material in the suboesophageal ganglion, oesophageal nerve and associated ganglia and intestine indicate important roles of

  17. Non-excitatory electrical stimulation attenuates myocardial infarction via homeostasis of calcitonin gene-related peptide in myocardium.

    PubMed

    Guo, Zhi-Jia; Guo, Zheng

    2015-03-01

    Electrical stimulation has been shown protection of brain, retina, optic nerves and pancreatic β-cells but the effect on cardio-protection is still unknown. Calcitonin gene-related peptide (CGRP) participates in the pathology of injury and protection of myocardium but whether or not electrical stimulation modulates endogenous CGRP is not clear. Male Sprague-Dawley rats were divided into 4 groups: (1) control group, without any treatment. (2) I/R group, animals were subjected to 30 min of myocardial ischemia followed by 60 min reperfusion. (3) NES+I/R group, non-excitatory electrical stimulation (NES) was commenced from 15 min before coronary artery occlusion till the end of reperfusion. (4) I/R+CGRP8-37 group, animals were given with CGRP8-37 (an antagonist of CGRP receptor, 10(-7) mol/L, 0.3 ml, i.v.) at 5 min before reperfusion without any electrical stimulation. The hemodynamics and electrocardiogram were monitored and recorded. Infarct size and troponin I were examined and CGRP expression in the myocardium and serum was analyzed. It was found that the infarct size and TnI were significantly reduced in NES+I/R group, by 45% and 58% respectively, accompanied by an obvious fall back of CGRP in myocardium, compared to I/R group (all p<0.05). Treatment with CGRP8-37 resulted in the same protection on myocardium as NES did. No significant difference in hemodynamics or ventricular tachycardia was detected among the groups (all p>0.05). It can be concluded that NES reduced the infarction size after acute myocardial ischemia and reperfusion, for which the underlying mechanism may be associated with modulation of endogenous CGRP in myocardium.

  18. GH-releasing peptide-2 does not stimulate arginine vasopressin secretion in healthy men.

    PubMed

    Kamoi, Kyuzi; Minagawa, Shinichi; Kimura, Keita; Ishizawa, Masahiro; Ohara, Nobumasa; Uemura, Yasuyuki; Tsuchiya, Junpei

    2010-01-01

    Ghrelin has a stimulating effect on arginine vasopressin (AVP). However, it is not known whether GHRP-2, a synthetic ghrelin receptor agonist, also has a stimulating effect on AVP release in men. To determine whether the GHRP-2 test is useful for assessing AVP secretion, blood ACTH, GH, FSH, LH, PRL, TSH and AVP levels, as well as glucose, osmolality, sodium and hematocrit, were measured before and 15, 30, 45 and 60 min after an intravenous bolus of 100 microg GHRP-2 in 10 healthy men with and without fasting. Blood pressure was measured at 15-min intervals. AVP secretion was not stimulated by the GHRP-2 test with and without fasting. There were no significant differences in hematocrit, blood pressure and plasma osmolality before and after GFRP-2 injection, although significant (p<0.001) peak blood GH, and ACTH and PRL levels were observed 30 and 15 min after GHRP-2 injection with and without fasting, respectively, and the maximal peaks were significantly (p<0.05) higher with fasting than without fasting. These results suggest that AVP secretion is not stimulated by the GHRP-2 test both with and without fasting, though GH, ACTH and PRL levels were higher with than without fasting.

  19. The kiwi fruit peptide kissper displays anti-inflammatory and anti-oxidant effects in in-vitro and ex-vivo human intestinal models.

    PubMed

    Ciacci, C; Russo, I; Bucci, C; Iovino, P; Pellegrini, L; Giangrieco, I; Tamburrini, M; Ciardiello, M A

    2014-03-01

    Literature reports describe kiwi fruit as a food with significant effects on human health, including anti-oxidant and anti-inflammatory activity. Fresh fruit or raw kiwi fruit extracts have been used so far to investigate these effects, but the molecule(s) responsible for these health-promoting activities have not yet been identified. Kissper is a kiwi fruit peptide displaying pore-forming activity in synthetic lipid bilayers, the composition of which is similar to that found in intestinal cells. The objective of this study was to investigate the kissper influence on intestinal inflammation using cultured cells and ex-vivo tissues from healthy subjects and Crohn's disease (CD) patients. The anti-oxidant and anti-inflammatory properties of kissper were tested on Caco-2 cells and on the colonic mucosa from 23 patients with CD, by challenging with the lipopolysaccharide from Escherichia coli (EC-LPS) and monitoring the appropriate markers by Western blot and immunofluorescence. EC-LPS challenge determined an increase in the intracellular concentration of calcium and reactive oxygen species (ROS). The peptide kissper was highly effective in preventing the increase of LPS-induced ROS levels in both the Caco-2 cells and CD colonic mucosa. Moreover, it controls the calcium increase, p65-nuclear factor (NF)-kB induction and transglutaminase 2 (TG2) activation inflammatory response in Caco-2 cells and CD colonic mucosa. Kissper efficiently counteracts the oxidative stress and inflammatory response in valuable model systems consisting of intestinal cells and CD colonic mucosa. This study reports the first evidence supporting a possible correlation between some beneficial effects of kiwi fruit and a specific protein molecule rather than generic nutrients.

  20. Supplementation with branched-chain amino acids to a low-protein diet regulates intestinal expression of amino acid and peptide transporters in weanling pigs.

    PubMed

    Zhang, Shihai; Qiao, Shiyan; Ren, Man; Zeng, Xiangfang; Ma, Xi; Wu, Zhenlong; Thacker, Philip; Wu, Guoyao

    2013-11-01

    This study determined the effects of dietary branched-chain amino acids (AA) (BCAA) on growth performance, expression of jejunal AA and peptide transporters, and the colonic microflora of weanling piglets fed a low-protein (LP) diet. One hundred and eight Large White × Landrace × Duroc piglets (weaned at 28 days of age) were fed a normal protein diet (NP, 20.9 % crude protein), an LP diet (LP, 17.1 % crude protein), or an LP diet supplemented with BCAA (LP + BCAA, 17.9 % crude protein) for 14 days. Dietary protein restriction reduced piglet growth performance and small-intestinal villous height, which were restored by BCAA supplementation to the LP diet to values for the NP diet. Serum concentrations of BCAA were reduced in piglets fed the LP diet while those in piglets fed the LP + BCAA diet were similar to values for the NP group. mRNA levels for Na(+)-neutral AA exchanger-2, cationic AA transporter-1, b(0,+) AA transporter, and 4F2 heavy chain were more abundant in piglets fed the LP + BCAA diet than the LP diet. However, mRNA and protein levels for peptide transporter-1 were lower in piglets fed the LP + BCAA diet as compared to the LP diet. The colonic microflora did not differ among the three groups of pigs. In conclusion, growth performance, intestinal development, and intestinal expression of AA transporters in weanling piglets are enhanced by BCAA supplementation to LP diets. Our findings provide a new molecular basis for further understanding of BCAA as functional AA in animal nutrition.

  1. Reducing renal uptake of 90Y- and 177Lu-labeled alpha-melanocyte stimulating hormone peptide analogues

    SciTech Connect

    Miao, Yubin; Fisher, Darrell R.; Quinn, Thomas P.

    2006-06-15

    The purpose of this study was to improve the tumor-to-kidney uptake ratios of 90Y- and 177Lu-[1,2,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-Re-Cys,D-Phe,Arg]alpha-melanocyte stimulating hormone (DOTA-RE(Arg)CCMSH), through coupling a negatively charged glutamic acid (Glu) to the peptide sequence. A new peptide of DOTA-Re(Glu,Arg)CCMSH was designed, synthesized and labeled with 90Y and 177Lu. Pharmacokinetics of 90Y- and 177Lu-DOTA-RE(Glu,Arg)CCNSH were determined in B16/F1 murine melanoma-bearing C57 mice. Both exhibited significantly less renal uptake than 90Y- and 177Lu-DOTA-Re(Arg)CCMSH at 30 min and at 2, 3, and 24 h after dose administration. The renal uptake values of 90Y- and 177Lu-DOTA-Re(Glu,Arg)CCMSH were 28.16% and 28.81% of those of 90Y- and 177Lu-DOTA-RE(Arg)CCMSH, respectively, at 4 hr post-injection. We also showed higher tumor-to-kidney uptake ratios 2.28 and 1.69 times that of 90Y- and 177Lu-DOTA-Re(Arg)CCMSH, respectively, at 4 h post-injection. The90Y- and 177Lu-DOTA-Re(Glu,Arg)CCMSH activity accumulation was low in normal organs except for kidneys. Coupling a negatively charged amino acid (Glu) to the CCMSH peptide sequence dramatically reduced the renal uptake values and increased the tumor-to-kidney uptake ratios of 90Y- and 177Lu-DOTA-Re(Glu,Arg)CCMSH, facilitating their potential applications as radiopharmaceuticals for targeted radionuclide therapy of melanoma.

  2. A Nascent Peptide Signal Responsive to Endogenous Levels of Polyamines Acts to Stimulate Regulatory Frameshifting on Antizyme mRNA*

    PubMed Central

    Yordanova, Martina M.; Wu, Cheng; Andreev, Dmitry E.; Sachs, Matthew S.; Atkins, John F.

    2015-01-01

    The protein antizyme is a negative regulator of cellular polyamine concentrations from yeast to mammals. Synthesis of functional antizyme requires programmed +1 ribosomal frameshifting at the 3′ end of the first of two partially overlapping ORFs. The frameshift is the sensor and effector in an autoregulatory circuit. Except for Saccharomyces cerevisiae antizyme mRNA, the frameshift site alone only supports low levels of frameshifting. The high levels usually observed depend on the presence of cis-acting stimulatory elements located 5′ and 3′ of the frameshift site. Antizyme genes from different evolutionary branches have evolved different stimulatory elements. Prior and new multiple alignments of fungal antizyme mRNA sequences from the Agaricomycetes class of Basidiomycota show a distinct pattern of conservation 5′ of the frameshift site consistent with a function at the amino acid level. As shown here when tested in Schizosaccharomyces pombe and mammalian HEK293T cells, the 5′ part of this conserved sequence acts at the nascent peptide level to stimulate the frameshifting, without involving stalling detectable by toe-printing. However, the peptide is only part of the signal. The 3′ part of the stimulator functions largely independently and acts at least mostly at the nucleotide level. When polyamine levels were varied, the stimulatory effect was seen to be especially responsive in the endogenous polyamine concentration range, and this effect may be more general. A conserved RNA secondary structure 3′ of the frameshift site has weaker stimulatory and polyamine sensitizing effects on frameshifting. PMID:25998126

  3. The HtrA protease from Streptococcus pneumoniae digests both denatured proteins and the competence-stimulating peptide.

    PubMed

    Cassone, Marco; Gagne, Alyssa L; Spruce, Lynn A; Seeholzer, Steven H; Sebert, Michael E

    2012-11-09

    The HtrA protease of Streptococcus pneumoniae functions both in a general stress response role and as an error sensor that specifically represses genetic competence when the overall level of biosynthetic errors in cellular proteins is low. However, the mechanism through which HtrA inhibits development of competence has been unknown. We found that HtrA digested the pneumococcal competence-stimulating peptide (CSP) and constituted the primary extracytoplasmic CSP-degrading activity in cultures of S. pneumoniae. Mass spectrometry demonstrated that cleavage predominantly followed residue Phe-8 of the CSP-1 isoform of the peptide within its central hydrophobic patch, and in competition assays, both CSP-1 and CSP-2 interacted with HtrA with similar efficiencies. More generally, analysis of β-casein digestion and of digestion within HtrA itself revealed a preference for substrates with non-polar residues at the P1 site. Consistent with a specificity for exposed hydrophobic residues, competition from native BSA only weakly inhibited digestion of CSP, but denaturation converted BSA into a strong competitive inhibitor of such proteolysis. Together these findings support a model in which digestion of CSP by HtrA is reduced in the presence of other unfolded proteins that serve as alternative targets for degradation. Such competition may provide a mechanism by which HtrA functions in a quality control capacity to monitor the frequency of biosynthetic errors that result in protein misfolding.

  4. Antisecretory Factor Peptide AF-16 Inhibits the Secreted Autotransporter Toxin-Stimulated Transcellular and Paracellular Passages of Fluid in Cultured Human Enterocyte-Like Cells

    PubMed Central

    Nicolas, Valérie

    2014-01-01

    Both the endogenous antisecretory factor (AF) protein and peptide AF-16, which has a sequence that matches that of the active N-terminal region of AF, inhibit the increase in the epithelial transport of fluid and electrolytes induced by bacterial toxins in animal and ex vivo models. We conducted a study to investigate the inhibitory effect of peptide AF-16 against the increase of transcellular passage and paracellular permeability promoted by the secreted autotransporter toxin (Sat) in a cultured cellular model of the human intestinal epithelial barrier. Peptide AF-16 produced a concentration-dependent inhibition of the Sat-induced increase in the formation of fluid domes, in the mucosal-to-serosal passage of d-[1-14C]mannitol, and in the rearrangements in the distribution and protein expression of the tight junction (TJ)-associated proteins ZO-1 and occludin in cultured human enterocyte-like Caco-2/TC7 cell monolayers. In addition, we show that peptide AF-16 also inhibits the cholera toxin-induced increase of transcellular passage and the Clostridium difficile toxin-induced effects on paracellular permeability and TJ protein organization in Caco-2/TC7 cell monolayers. Treatment of cell monolayers by the lipid raft disorganizer methyl-β-cyclodextrin abolished the inhibitory activity of peptide AF-16 at the transcellular passage level and did not modify the effect of the peptide at the paracellular level. PMID:25534938

  5. Seasonal plasticity in the peptide neuronal systems: potential roles of gonadotrophin-releasing hormone, gonadotrophin-inhibiting hormone, neuropeptide Y and vasoactive intestinal peptide in the regulation of the reproductive axis in subtropical Indian weaver birds.

    PubMed

    Surbhi; Rastogi, A; Rani, S; Kumar, V

    2015-05-01

    Two experiments examined the expression of gonadotrophin-releasing and inhibiting hormones (GnRH-I, GnRH-II and GnIH), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) in subtropical Indian weaver birds, which demonstrate relative photorefractoriness. Experiment 1 measured peptide expression levels in the form of immunoreactive (-IR) cells, percentage cell area and cell optical density in the preoptic area (GnRH-I), midbrain (GnRH-II), paraventricular nucleus (GnIH), mediobasal hypothalamus [dorsomedial hypothalamus (DMH), infundibular complex (INc), NPY and VIP] and lateral septal organ (VIP) during the progressive, breeding, regressive and nonbreeding phases of the annual reproductive cycle. GnRH-I was decreased in the nonbreeding and VIP was increased in INc in the breeding and regressive states. GnRH-II and NPY levels did not differ between the testicular phases. Double-labelled immunohistochemistry (IHC) revealed a close association between the GnRH/GnIH, GnRH/NPY, GnRH/VIP and GnIH/NPY peptide systems, implicating them interacting and playing roles in the reproductive regulation in weaver birds. Experiment 2 further measured these peptide levels in the middle of day and night in weaver birds that were maintained under short days (8 : 16 h light /dark cycle; photosensitive), exposed to ten long days (16 : 8 h light /dark cycle; photostimulated) or maintained for approximately 2 years on a 16 : 8 h light /dark cycle (photorefractory). Reproductively immature testes in these groups precluded the possible effect of an enhanced gonadal feedback on the hypothalamic peptide expression. There were group differences in the GnRH-I (not GnRH-II), GnIH, NPY and VIP immunoreactivity, albeit with variations in immunoreactivity measures in the present study. These results, which are consistent with those reported in birds with relative photorefractoriness, show the distribution and possibly a complex interaction of key neuropeptides in the regulation of the

  6. Mechanism of Action of Glucagon-Like Peptide-2 to Increase IGF-I mRNA in Intestinal Subepithelial Fibroblasts

    PubMed Central

    Leen, Jason L. S.; Izzo, Angelo; Upadhyay, Chandani; Rowland, Katherine J.; Dubé, Philip E.; Gu, Steven; Heximer, Scott P.; Rhodes, Christopher J.; Storm, Daniel R.; Lund, P. Kay

    2011-01-01

    IGF-I, a known secretory product of intestinal subepithelial myofibroblasts (ISEMFs), is essential for the intestinotropic effects of glucagon-like peptide-2 (GLP-2). Furthermore, GLP-2 increases IGF-I mRNA transcript levels in vitro in heterogeneous fetal rat intestinal cultures, as well as in vivo in the rodent small intestine. To determine the mechanism underlying the stimulatory effect of GLP-2 on intestinal IGF-I mRNA, murine ISEMF cells were placed into primary culture. Immunocytochemistry showed that the ISEMF cells appropriately expressed α-smooth muscle actin and vimentin but not desmin. The cells also expressed GLP-2 receptor and IGF-I mRNA transcripts. Treatment of ISEMF cells with (Gly2)GLP-2 induced IGF-I mRNA transcripts by up to 5-fold of basal levels after treatment with 10−8 m GLP-2 for 2 h (P < 0.05) but did not increase transcript levels for other intestinal growth factors, such as ErbB family members. Immunoblot revealed a 1.6-fold increase in phospho (p)-Akt/total-(t)Akt with 10−8 m GLP-2 treatment (P < 0.05) but no changes in cAMP, cAMP-dependent β-galactosidase expression, pcAMP response element-binding protein/tcAMP response element-binding protein, pErk1/2/tErk1/2, or intracellular calcium. Furthermore, pretreatment of ISEMF cells with the phosphatidylinositol 3 kinase (PI3K) inhibitors, LY294002 and wortmannin, abrogated the IGF-I mRNA response to GLP-2, as did overexpression of kinase-dead Akt. The role of PI3K/Akt in GLP-2-induced IGF-I mRNA levels in the murine jejunum was also confirmed in vivo. These findings implicate the PI3K/Akt pathway in the stimulatory effects of GLP-2 to enhance intestinal IGF-I mRNA transcript levels and provide further evidence in support of a role for IGF-I produced by the ISEMF cells in the intestinotropic effects of GLP-2. PMID:21159855

  7. Biphasic peptide amphiphile nanomatrix embedded with hydroxyapatite nanoparticles for stimulated osteoinductive response.

    PubMed

    Anderson, Joel M; Patterson, Jessica L; Vines, Jeremy B; Javed, Amjad; Gilbert, Shawn R; Jun, Ho-Wook

    2011-12-27

    Formation of the native bone extracellular matrix (ECM) provides an attractive template for bone tissue engineering. The structural support and biological complexity of bone ECM are provided within a composite microenvironment that consists of an organic fibrous network reinforced by inorganic hydroxyapatite (HA) nanoparticles. Recreating this biphasic assembly, a bone ECM analogous scaffold comprising self-assembling peptide amphiphile (PA) nanofibers and interspersed HA nanoparticles was investigated. PAs were endowed with biomolecular ligand signaling using a synthetically inscribed peptide sequence (i.e., RGDS) and integrated with HA nanoparticles to form a biphasic nanomatrix hydrogel. It was hypothesized the biphasic hydrogel would induce osteogenic differentiation of human mesenchymal stem cells (hMSCs) and improve bone healing as mediated by RGDS ligand signaling within PA nanofibers and embedded HA mineralization source. Viscoelastic stability of the biphasic PA hydrogels was evaluated with different weight concentrations of HA for improved gelation. After demonstrating initial viability, long-term cellularity and osteoinduction of encapsulated hMSCs in different PA hydrogels were studied in vitro. Temporal progression of osteogenic maturation was assessed by gene expression of key markers. A preliminary animal study demonstrated bone healing capacity of the biphasic PA nanomatrix under physiological conditions using a critical size femoral defect rat model. The combination of RGDS ligand signaling and HA nanoparticles within the biphasic PA nanomatrix hydrogel demonstrated the most effective osteoinduction and comparative bone healing response. Therefore, the biphasic PA nanomatrix establishes a well-organized scaffold with increased similarity to natural bone ECM with the prospect for improved bone tissue regeneration.

  8. Speract, a sea urchin egg peptide that regulates sperm motility, also stimulates sperm mitochondrial metabolism.

    PubMed

    García-Rincón, Juan; Darszon, Alberto; Beltrán, Carmen

    2016-04-01

    Sea urchin sperm have only one mitochondrion, that in addition to being the main source of energy, may modulate intracellular Ca(2+) concentration ([Ca(2+)]i) to regulate their motility and possibly the acrosome reaction. Speract is a decapeptide from the outer jelly layer of the Strongylocentrotus purpuratus egg that upon binding to its receptor in the sperm, stimulates sperm motility, respiration and ion fluxes, among other physiological events. Altering the sea urchin sperm mitochondrial function with specific inhibitors of this organelle, increases [Ca(2+)]i in an external Ca(2+) concentration ([Ca(2+)]ext)-dependent manner (Ardón, et al., 2009. BBActa 1787: 15), suggesting that the mitochondrion is involved in sperm [Ca(2+)]i homeostasis. To further understand the interrelationship between the mitochondrion and the speract responses, we measured mitochondrial membrane potential (ΔΨ) and NADH levels. We found that the stimulation of sperm with speract depolarizes the mitochondrion and increases the levels of NADH. Surprisingly, these responses are independent of external Ca(2+) and are due to the increase in intracellular pH (pHi) induced by speract. Our findings indicate that speract, by regulating pHi, in addition to [Ca(2+)]i, may finely modulate mitochondrial metabolism to control motility and ensure that sperm reach the egg and fertilize it.

  9. Ventilatory and cardiovascular actions of centrally and peripherally administered trout pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) in the unanaesthetized trout.

    PubMed

    Le Mével, J-C; Lancien, F; Mimassi, N; Conlon, J M

    2009-12-01

    In mammals, pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) are involved in cardiovascular and respiratory regulation. Several studies have demonstrated the presence of PACAP, VIP and their receptors in various tissues of teleost fish, including the brain, but little is known about their respiratory and cardiovascular effects. The present study was undertaken to compare the central and peripheral actions of graded doses (25-100 pmol) of trout PACAP and trout VIP on ventilatory and cardiovascular variables in the unanaesthetized rainbow trout. Compared with vehicle, only intracerebroventricular injection of PACAP significantly (P<0.05) elevated the ventilation frequency and the ventilation amplitude, but both peptides significantly increased the total ventilation (total ventilation). However, the maximum hyperventilatory effect of PACAP was approximately 2.5-fold higher than the effect of VIP at the 100 pmol dose (PACAP, (total ventilation)=+5407+/-921 arbitrary units, a.u.; VIP, (total ventilation)=+2056+/-874 a.u.; means +/- s.e.m.). When injected centrally, only PACAP produced a significant increase in mean dorsal aortic blood pressure (P(DA)) (100 pmol: +21%) but neither peptide affected heart rate (f(H)). Intra-arterial injections of either PACAP or VIP were without effect on the ventilatory variables. PACAP was without significant action on P(DA) and f(H) while VIP significantly elevated P(DA) (100 pmol: +36%) without changing f(H). In conclusion, the selective central hyperventilatory actions of exogenously administered trout PACAP, and to a lesser extent VIP, suggest that the endogenous peptides may be implicated in important neuroregulatory functions related to the central control of ventilation in trout.

  10. The mRNA expression of amino acid transporters, aminopeptidase, and the di- and tri-peptide transporter PepT1 in the intestine and liver of post-hatch broiler chicks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amino acid transporter (AAT) proteins are responsible for the movement of amino acids (AA) in and out of cells. Aminopeptidase (APN) cleaves AAs from the N terminus of polypeptides making them available for transport, while PepT1 is a di- and tri- peptide transporter. In the intestine, these prote...

  11. The opioid peptide beta-endorphin stimulates acrosome reaction in human spermatozoa.

    PubMed

    Urizar-Arenaza, I; Estomba, H; Muñoa-Hoyos, I; Matorras, R; Esposito, A; Candenas, L; Pinto, F M; Valdivia, A; Irazusta, J; Subirán, N

    2016-01-01

    The acrosome reaction occurs in vivo following sperm capacitation and is essential for the acquisition of sperm fertilization ability. However, little is known about the molecular identity of the physiological acrosome reaction regulators. In addition to progesterone, which is produced by cumulus oophorus cells and known to regulate acrosome reaction by activating the specific calcium channel CatSper, endogenous opioid peptides such as beta-endorphin and met-enkephalin are present at high concentrations in the follicular fluid suggesting that the opioid system may be involved in the mechanisms regulating the acrosome reaction in humans. By using Reverse Transcription-PCR, western blot and immunofluorescence approaches, we described the presence and localization of the beta-endorphin precursor, pro-opiomelanocortinin the middle section and in flagellum of human spermatozoa, and inside the seminiferous tubules of human testis. Flow cytometry and intracellular calcium analyses showed that beta-endorphin causes an inversely dose-dependent increase in the percentage of acrosome-reacted sperm cells by a calcium-independent protein kinase C pathway. These findings are important for future studies of sperm physiology and provide new insight into the function of the opioid system as a target of fertility management.

  12. The dietary ingredient, genistein, stimulates cathelicidin antimicrobial peptide expression through a novel S1P-dependent mechanism.

    PubMed

    Park, Kyungho; Kim, Young-Il; Shin, Kyong-Oh; Seo, Ho Seong; Kim, Jong Youl; Mann, Taj; Oda, Yuko; Lee, Yong-Moon; Holleran, Walter M; Elias, Peter M; Uchida, Yoshikazu

    2014-07-01

    We recently discovered that a signaling lipid, sphingosine-1-phosphate (S1P), generated by sphingosine kinase 1, regulates a major epidermal antimicrobial peptide's [cathelicidin antimicrobial peptide (CAMP)] expression via an NF-κB→C/EBPα-dependent pathway, independent of vitamin D receptor (VDR) in epithelial cells. Activation of estrogen receptors (ERs) by either estrogens or phytoestrogens also is known to stimulate S1P production, but it is unknown whether ER activation increases CAMP production. We investigated whether a phytoestrogen, genistein, simulates CAMP expression in keratinocytes, a model of epithelial cells, by either a S1P-dependent mechanism(s) or the alternate VDR-regulated pathway. Exogenous genistein, as well as an ER-β ligand, WAY-200070, increased CAMP mRNA and protein expression in cultured human keratinocytes, while ER-β antagonist, ICI182780, attenuated the expected genistein- and WAY-200070-induced increase in CAMP mRNA/protein expression. Genistein treatment increased acidic and alkaline ceramidase expression and cellular S1P levels in parallel with increased S1P lyase inhibition, accounting for increased CAMP production. In contrast, siRNA against VDR did not alter genistein-mediated up-regulation of CAMP. Taken together, genistein induces CAMP production via an ER-β→S1P→NF-κB→C/EBPα- rather than a VDR-dependent mechanism, illuminating a new role for estrogens in the regulation of epithelial innate immunity and pointing to potential additional benefits of dietary genistein in enhancing cutaneous antimicrobial defense.

  13. Novel Small Molecule Glucagon-Like Peptide-1 Receptor Agonist Stimulates Insulin Secretion in Rodents and From Human Islets

    PubMed Central

    Sloop, Kyle W.; Willard, Francis S.; Brenner, Martin B.; Ficorilli, James; Valasek, Kathleen; Showalter, Aaron D.; Farb, Thomas B.; Cao, Julia X.C.; Cox, Amy L.; Michael, M. Dodson; Gutierrez Sanfeliciano, Sonia Maria; Tebbe, Mark J.; Coghlan, Michael J.

    2010-01-01

    OBJECTIVE The clinical effectiveness of parenterally-administered glucagon-like peptide-1 (GLP-1) mimetics to improve glucose control in patients suffering from type 2 diabetes strongly supports discovery pursuits aimed at identifying and developing orally active, small molecule GLP-1 receptor agonists. The purpose of these studies was to identify and characterize novel nonpeptide agonists of the GLP-1 receptor. RESEARCH DESIGN AND METHODS Screening using cells expressing the GLP-1 receptor and insulin secretion assays with rodent and human islets were used to identify novel molecules. The intravenous glucose tolerance test (IVGTT) and hyperglycemic clamp characterized the insulinotropic effects of compounds in vivo. RESULTS Novel low molecular weight pyrimidine-based compounds that activate the GLP-1 receptor and stimulate glucose-dependent insulin secretion are described. These molecules induce GLP-1 receptor-mediated cAMP signaling in HEK293 cells expressing the GLP-1 receptor and increase insulin secretion from rodent islets in a dose-dependent manner. The compounds activate GLP-1 receptor signaling, both alone or in an additive fashion when combined with the endogenous GLP-1 peptide; however, these agonists do not compete with radiolabeled GLP-1 in receptor-binding assays. In vivo studies using the IVGTT and the hyperglycemic clamp in Sprague Dawley rats demonstrate increased insulin secretion in compound-treated animals. Further, perifusion assays with human islets isolated from a donor with type 2 diabetes show near-normalization of insulin secretion upon compound treatment. CONCLUSIONS These studies characterize the insulinotropic effects of an early-stage, small molecule GLP-1 receptor agonist and provide compelling evidence to support pharmaceutical optimization. PMID:20823098

  14. Combined treatment with dipeptidyl peptidase 4 (DPP4) inhibitor sitagliptin and elemental diets reduced indomethacin-induced intestinal injury in rats via the increase of mucosal glucagon-like peptide-2 concentration

    PubMed Central

    Fujiwara, Kaori; Inoue, Takuya; Yorifuji, Naoki; Iguchi, Munetaka; Sakanaka, Taisuke; Narabayashi, Ken; Kakimoto, Kazuki; Nouda, Sadaharu; Okada, Toshihiko; Ishida, Kumi; Abe, Yosuke; Masuda, Daisuke; Takeuchi, Toshihisa; Fukunishi, Shinya; Umegaki, Eiji; Akiba, Yasutada; Kaunitz, Jonathan D.; Higuchi, Kazuhide

    2015-01-01

    The gut incretin glucagon-like peptide-1 (GLP-1) and the intestinotropic hormone GLP-2 are released from enteroendocrine L cells in response to ingested nutrients. Treatment with an exogenous GLP-2 analogue increases intestinal villous mass and prevents intestinal injury. Since GLP-2 is rapidly degraded by dipeptidyl peptidase 4 (DPP4), DPP4 inhibition may be an effective treatment for intestinal ulcers. We measured mRNA expression and DPP enzymatic activity in intestinal segments. Mucosal DPP activity and GLP concentrations were measured after administration of the DPP4 inhibitor sitagliptin (STG). Small intestinal ulcers were induced by indomethacin (IM) injection. STG was given before IM treatment, or orally administered after IM treatment with or without an elemental diet (ED). DPP4 mRNA expression and enzymatic activity were high in the jejunum and ileum. STG dose-dependently suppressed ileal mucosal enzyme activity. Treatment with STG prior to IM reduced small intestinal ulcer scores. Combined treatment with STG and ED accelerated intestinal ulcer healing, accompanied by increased mucosal GLP-2 concentrations. The reduction of ulcers by ED and STG was reversed by co-administration of the GLP-2 receptor antagonist. DPP4 inhibition combined with luminal nutrients, which up-regulate mucosal concentrations of GLP-2, may be an effective therapy for the treatment of small intestinal ulcers. PMID:25759522

  15. Monocytes from Sjögren's syndrome patients display increased vasoactive intestinal peptide receptor 2 expression and impaired apoptotic cell phagocytosis

    PubMed Central

    Hauk, V; Fraccaroli, L; Grasso, E; Eimon, A; Ramhorst, R; Hubscher, O; Pérez Leirós, C

    2014-01-01

    Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by salivary and lacrimal gland dysfunction. Clinical observations and results from animal models of SS support the role of aberrant epithelial cell apoptosis and immune homeostasis loss in the glands as triggering factors for the autoimmune response. Vasoactive intestinal peptide (VIP) promotes potent anti-inflammatory effects in several inflammatory and autoimmune disease models, including the non-obese diabetic (NOD) mouse model of SS. With the knowledge that VIP modulates monocyte function through vasoactive intestinal peptide receptors (VPAC) and that immune homeostasis maintenance depends strongly upon a rapid and immunosuppressant apoptotic cell clearance by monocytes/macrophages, in this study we explored VPAC expression on monocytes from primary SS (pSS) patients and the ability of VIP to modulate apoptotic cell phagocytic function and cytokine profile. Monocytes isolated from individual pSS patients showed an increased expression of VPAC2 subtype of VIP receptors, absent in monocytes from control subjects, with no changes in VPAC1 expression. VPAC2 receptor expression could be induced further with lipopolysaccharide (LPS) in pSS monocytes and VIP inhibited the effect. Moreover, monocytes from pSS patients showed an impaired phagocytosis of apoptotic epithelial cells, as evidenced by reduced engulfment ability and the failure to promote an immunosuppressant cytokine profile. However, VIP neither modulated monocyte/macrophage phagocytic function nor did it reverse their inflammatory profile. We conclude that monocytes from pSS patients express high levels of VPAC2 and display a deficient clearance of apoptotic cells that is not modulated by VIP. PMID:24827637

  16. Annexin II binds progastrin and gastrin-like peptides, and mediates growth factor effects of autocrine and exogenous gastrins on colon cancer and intestinal epithelial cells.

    PubMed

    Singh, P; Wu, H; Clark, C; Owlia, A

    2007-01-18

    We and others have reported the presence of novel progastrin (PG)/gastrin receptors on normal and cancerous intestinal cells. We had earlier reported the presence of 33-36 kDa gastrin-binding proteins on cellular membranes of colon cancer cells. The goal of the current study was to identify the protein(s) in the 33-36 kDa band, and analyse its functional significance. A carbodiimide crosslinker was used for crosslinking radio-labeled gastrins to membrane proteins from gastrin/PG responsive cell lines. Native membrane proteins, crosslinked to the ligand, were solubulized and enriched by >1000-fold, and analysed by surface-enhanced laser desorption/ionization-time of flight-mass spectrometry. The peptide masses were researched against the NCBInr database using the ProFound search engine. Annexin II (ANX II) was identified, and confirmed by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry. As HCT-116 cells express autocrine PG, the in situ association of PG with ANX II was demonstrated in pulldown assays. Direct binding of PG with ANX II was confirmed in an in vitro binding assay. In order to confirm a functional importance of these observations, sense and anti-sense (AS) ANX II RNA-expressing clones of intestinal epithelial (IEC-18) and human colon cancer (HCT-116) cell lines were generated. AS clones demonstrated a significant loss in the growth response to exogenous (IEC-18) and autocrine (HCT-116) PG. We have thus discovered that membrane-associated ANX II binds PG/gastrins, and partially mediates growth factor effects of the peptides.

  17. SKPDT is a signaling peptide that stimulates sporulation and cry1Aa expression in Bacillus thuringiensis but not in Bacillus subtilis.

    PubMed

    Aceves-Diez, Angel E; Robles-Burgueño, Refugio; de la Torre, Mayra

    2007-08-01

    We have identified and characterized in the supernatant of the transition phase of Bacillus thuringiensis var. kurstaki the peptide SKPDT. This peptide was previously identified by in silico analysis by Pottathil and Lazazzera (Front Biosci 8:32-45 2003) as a putative signaling peptide (NprRB) of the Phr family in B. thuringiensis. The chemically synthesized NprRB did not affect the growth kinetics of B. thuringiensis var. kurstaki but stimulated the sporulation, spore release, and transcription of cry1Aa when added to cultures during the transition phase. In fact, when the peptide (100 nM) was added to a culture in transition phase, the transcription of cry1Aa was stimulated almost threefold, mainly from the late promoter BtII, which requires the late-stage sporulation-specific transcription factor sigma (K). On the other hand, NprRB did not have any effect on B. subtilis. Thus, SKPDT seems to be a signaling peptide specific for B. thuringiensis.

  18. A stereological evaluation of secretin and gastric inhibitory peptide-containing mucosal cells of the perinatal small intestine of the pig.

    PubMed

    Van Ginneken, C; Weyns, A

    2004-10-01

    Stereological methods were used to quantify secretin and gastric inhibitory peptide (GIP)-immunoreactivity (GIP-IR) in paraffin sections of the duodenum, jejunum and ileum of fetal and neonatal piglets. In addition, sections were processed for GLP-1-immunohistochemistry. The volume density of the tunica mucosa increased after birth, giving rise to a decreased volume density of the tela submucosa and tunica muscularis. Generally known region-specific morphological distinctions were reflected in differing volume densities of the various layers. The highest volume density of GIP-IR epithelial cells was observed in the jejunum of the neonate. In contrast, the volume density of secretin-IR epithelial cells was highest in the duodenum of both fetal and neonatal piglets. The volume occupied by GIP-IR and secretin-IR epithelial cells increased in the jejunum after birth. Additionally, ileal secretin-IR epithelial cells were more numerous in the neonatal piglet. In conclusion, the quantitative and qualitative presence of GIP-IR and secretin-IR epithelial cells agree with earlier reports of their presence and co-localization between GIP-IR and GLP-1-IR, in the pig small intestine. Furthermore, the differences suggest that age- and region-related functional demands are temporally and probably causally related with the morphological diversification of the intestine and its endocrine cells.

  19. Short Bowel Patients Treated for Two Years with Glucagon-Like Peptide 2: Effects on Intestinal Morphology and Absorption, Renal Function, Bone and Body Composition, and Muscle Function

    PubMed Central

    Jeppesen, P. B.; Lund, P.; Gottschalck, I. B.; Nielsen, H. B.; Holst, J. J.; Mortensen, J.; Poulsen, S. S.; Quistorff, B.; Mortensen, P. B.

    2009-01-01

    Background and aims. In a short-term study, Glucagon-like peptide 2 (GLP-2) has been shown to improve intestinal absorption in short bowel syndrome (SBS) patients. This study describes longitudinal changes in relation to GLP-2 treatment for two years. Methods. GLP-2, 400 micrograms, s.c.,TID, were offered, to eleven SBS patients keeping parenteral support constant. 72-hour nutritional balance studies were performed at baseline, weeks 13, 26, 52 during two years intermitted by an 8-week washout period. In addition, mucosal morphometrics, renal function (by creatinine clearance), body composition and bone mineral density (by DEXA), biochemical markers of bone turnover (by s-CTX and osteocalcin, PTH and vitamin D), and muscle function (NMR, lungfunction, exercise test) were measured. Results. GLP-2 compliance was >93%. Three of eleven patients did not complete the study. In the remaining 8 patients, GLP-2 significantly reduced the fecal wet weight from approximately 3.0 to approximately 2.0 kg/day. This was accompanied by a decline in the oral wet weight intake, maintaining intestinal wet weight absorption and urinary weight constant. Renal function improved. No significant changes were demonstrated in energy intake or absorption, and GLP-2 did not significantly affect mucosal morphology, body composition, bone mineral density or muscle function. Conclusions. GLP-2 treatment reduces fecal weight by approximately 1000 g/d and enables SBS patients to maintain their intestinal fluid and electrolyte absorption at lower oral intakes. This was accompanied by a 28% improvement in creatinine clearance. PMID:19707516

  20. Glucose-dependent insulinotropic peptide stimulates thymidine incorporation in endothelial cells: role of endothelin-1

    NASA Technical Reports Server (NTRS)

    Ding, Ke-Hong; Zhong, Qing; Isales, Carlos M.; Iscules, C. M. (Principal Investigator)

    2003-01-01

    We have previously characterized the receptor for glucose-dependent insulinotropic polypeptide (GIPR) in vascular endothelial cells (EC). Different EC types were found to contain distinct GIPR splice variants. To determine whether activation of the GIPR splice variants resulted in different cellular responses, we examined GIP effects on human umbilical vein endothelial cells (HUVEC), which contain two GIPR splice variants, and compared them with a spontaneously transformed human umbilical vein EC line, ECV 304, which contains four GIPR splice variants. GIP dose-dependently stimulated HUVEC and ECV 304 proliferation as measured by [3H]thymidine incorporation. GIP increased endothelin-1 (ET-1) secretion from HUVEC but not from ECV 304. Use of the endothelin B receptor blocker BQ-788 resulted in an inhibition of [3H]thymidine incorporation in HUVEC but not in ECV 304. These findings suggest that, although GIP increases [3H]thymidine incorporation in both HUVEC and ECV 304, this proliferative response is mediated by ET-1 only in HUVEC. These differences in cellular response to GIP may be related to differences in activation of GIPR splice variants.

  1. In-Situ-Generated Vasoactive Intestinal Peptide Loaded Microspheres in Mussel-Inspired Polycaprolactone Nanosheets Creating Spatiotemporal Releasing Microenvironment to Promote Wound Healing and Angiogenesis.

    PubMed

    Wang, Yuzhen; Chen, Zhiqiang; Luo, Gaoxing; He, Weifeng; Xu, Kaige; Xu, Rui; Lei, Qiang; Tan, Jianglin; Wu, Jun; Xing, Malcolm

    2016-03-23

    Vasoactive intestinal peptide (VIP) was reported to promote angiogenesis. Electrospun nanofibers lead to idea wound dressing substrates. Here we report a convenient and novel method to produce VIP loaded microspheres in polycaprolactone (PCL) nanofibrous membrane without complicated processes. We first coated mussel-inspired dopamine (DA) to nanofibers, then used strong adhesive DA to absorb the functional peptide. PCL membrane was then immersed into acetone to generate microspheres with VIP loading. We employed high pressure liquid chromatography to record encapsulation efficiency of (31.8 ± 2.2)% and loading capacity of (1.71 ± 0.16)%. The release profile of VIP from nanosheets showed a prolonged release. The results of laser scanning confocal microscope, scanning electron microscope and cell counting kit-8 proliferation assays showed that cell adhesion and proliferation were promoted. In order to verify the efficacy on wound healing, in vivo implantation was applied in the full-thickness defect wounds of BALB/c mice. Results showed that the wound healing was significantly promoted via favoring the growth of granulation tissue and angiogenesis. However, we found wound re-epithelialization was not significantly improved. The resulting VIP-DA-coated PCL (PCL-DA-VIP) nanosheets with spatiotemporal delivery of VIP could be a potential application in wound treatment and vascular tissue engineering.

  2. VPAC2 (vasoactive intestinal peptide receptor type 2) receptor deficient mice develop exacerbated experimental autoimmune encephalomyelitis with increased Th1/Th17 and reduced Th2/Treg responses.

    PubMed

    Tan, Yossan-Var; Abad, Catalina; Wang, Yuqi; Lopez, Robert; Waschek, James A

    2015-02-01

    Vasoactive intestinal peptide (VIP) and pituitary adenylyl cyclase-activating polypeptide (PACAP) are two structurally-related neuropeptides with widespread expression in the central and peripheral nervous systems. Although these peptides have been repeatedly shown to exert potent anti-inflammatory actions when administered in animal models of inflammatory disease, mice deficient in VIP and PACAP were recently shown to exhibit different phenotypes (ameliorated and exacerbated, respectively) in response to experimental autoimmune encephalomyelitis (EAE). Therefore, elucidating what are the specific immunoregulatory roles played by each of their receptor subtypes (VPAC1, VPAC2, and PAC1) is critical. In this study, we found that mice with a genetic deletion of VIPR2, encoding the VPAC2 receptor, exhibited exacerbated (MOG35-55)-induced EAE compared to wild type mice, characterized by enhanced clinical and histopathological features, increased proinflammatory cytokines (TNF-α, IL-6, IFN-γ (Th1), and IL-17 (Th17)) and reduced anti-inflammatory cytokines (IL-10, TGFβ, and IL-4 (Th2)) in the CNS and lymph nodes. Moreover, the abundance and proliferative index of lymph node, thymus and CNS CD4(+)CD25(+)FoxP3(+) Tregs were strikingly reduced in VPAC2-deficient mice with EAE. Finally, the in vitro suppressive activity of lymph node and splenic Tregs from VPAC2-deficient mice was impaired. Overall, our results demonstrate critical protective roles for PACAP and the VPAC2 receptor against autoimmunity, promoting the expansion and maintenance of the Treg pool.

  3. Experimental Cancer Cachexia Changes Neuron Numbers and Peptide Levels in the Intestine: Partial Protective Effects after Dietary Supplementation with L-Glutamine

    PubMed Central

    Vicentini, Geraldo E.; Fracaro, Luciane; de Souza, Sara R. G.; Martins, Heber A.; Guarnier, Flávia A.; Zanoni, Jacqueline N.

    2016-01-01

    Gastrointestinal dysmotility frequently occurs in cancer cachexia and may result from damage to enteric innervation caused by oxidative stress, especially due to glutathione depletion. We assessed the effect of dietary supplementation with 20 g/kg l-glutamine (a glutathione precursor) on the intrinsic innervation of the enteric nervous system in healthy and Walker 256 tumor-bearing Wistar rats during the development of experimental cachexia (14 days), in comparison with non-supplemented rats, by using immunohistochemical methods and Western blotting. The total neural population and cholinergic subpopulation densities in the myenteric plexus, as well as the total population and VIPergic subpopulation in the submucosal plexus of the jejunum and ileum, were reduced in cachectic rats, resulting in adaptive morphometric alterations and an increase in vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP) expression, suggesting a neuroplastic response. l-glutamine supplementation prevented decrease in myenteric neuronal density in the ileum, morphometric alterations in the neurons and nerve fibers (in both the plexuses of the jejunum and ileum), and the overexpression of VIP and CGRP. Cancer cachexia severely affected the intrinsic innervation of the jejunum and ileum to various degrees and this injury seems to be associated with adaptive neural plasticity. l-glutamine supplementation presented partial protective effects on the enteric innervation against cancer cachexia, possibly by attenuating oxidative stress. PMID:27635657

  4. Protected Graft Copolymer Excipient Leads to a Higher Acute Maximum Tolerated Dose and Extends Residence Time of Vasoactive Intestinal Peptide Significantly Better than Sterically Stabilized Micelles

    PubMed Central

    Reichstetter, Sandra; Castillo, Gerardo M.; Rubinstein, Israel; Nishimoto-Ashfield, Akiko; Lai, ManShun; Jones, Cynthia C.; Banjeree, Aryamitra; Lyubimov, Alex; Bloedow, Duane C.; Bogdanov, Alexei; Bolotin, Elijah M.

    2013-01-01

    Purpose To determine and compare pharmacokinetics and toxicity of two nanoformulations of Vasoactive Intestinal Peptide (VIP). Methods VIP was formulated using a micellar (Sterically Stabilized Micelles, SSM) and a polymer-based (Protected Graft Copolymer, PGC) nanocarrier at various loading percentages. VIP binding to the nanocarriers, pharmacokinetics, blood pressure, blood chemistry, and acute maximum tolerated dose (MTD) of the formulations after injection into BALB/c mice were determined. Results Both formulations significantly extend in vivo residence time compared to unformulated VIP. Formulation toxicity is dependent on loading percentage, showing major differences between the two carrier types. Both formulations increase in vivo potency of unformulated VIP and show acute MTDs at least 140 times lower than unformulated VIP, but still at least 100 times higher than the anticipated highest human dose, 1–5 μg/kg. These nanocarriers prevented a significant drop in arterial blood pressure compared to unformulated VIP. Conclusions While both carriers enhance in vivo residence time compared to unformulated VIP and reduce the drop in blood pressure immediately after injection, PGC is the excipient of choice to extend residence time and improve the safety of potent therapeutic peptides such as VIP. PMID:23224976

  5. Acute effects of the glucagon-like peptide 2 analogue, teduglutide, on intestinal adaptation in short bowel syndrome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Neonatal short bowel syndrome following massive gut resection is associated with malabsorption of nutrients. The intestinotrophic factor glucagon-like peptide 2 (GLP-2) improves gut function in adult patients with short bowel syndrome, but its effect in pediatric patients remains unknown. Our object...

  6. Immunosuppressive activity of a novel peptide analog of α-melanocyte stimulating hormone (α-MSH) in experimental autoimmune uveitis.

    PubMed

    Edling, Andrea E; Gomes, Danilo; Weeden, Timothy; Dzuris, John; Stefano, Jim; Pan, Clark; Williams, John; Kaplan, Johanne; Perricone, Michael A

    2011-07-01

    Autoimmune uveitis is an inflammatory disorder of the eye that can lead to pain and vision loss. Steroids and immunosuppressive drugs are currently the only therapeutics for uveitis and have serious ocular and systemic toxicities. Therefore, safer alternative therapeutics are desired. Alpha-melanocyte stimulating hormone (α-MSH) is a neuropeptide that suppresses effector T cell functions, induces regulatory T cells and has beneficial effects in certain autoimmune and transplant models. A novel d-amino acid peptide analog of native α-MSH (dRI-α-MSH) was produced that was protected from protease digestion and had increased selectivity for the melanocortin-1 receptor. Systemic delivery of the dRI-α-MSH analog dramatically suppressed disease progression and retained retinal architecture in the experimental autoimmune uveitis (EAU) model. Local delivery by periorbital injection was equally effective. Importantly, treatment with the novel dRI-α-MSH analog suppressed uveitis with a similar magnitude to the corticosteroid, dexamethasone. Data indicate that the novel dRI-α-MSH analogs show anti-inflammatory activities and have potential therapeutic use in uveitis and other autoimmune diseases.

  7. Establishment and characterization of monoclonal and polyclonal antibodies against human intestinal fatty acid-binding protein (I-FABP) using synthetic regional peptides and recombinant I-FABP.

    PubMed

    Kajiura, Satoshi; Yashiki, Tetsuya; Funaoka, Hiroyuki; Ohkaru, Yasuhiko; Nishikura, Ken; Kanda, Tatsuo; Ajioka, Yoichi; Igarashi, Michihiro; Hatakeyama, Katsuyoshi; Fujii, Hiroshi

    2008-01-01

    We have succeeded in raising highly specific anti-human intestinal fatty acid-binding protein (I-FABP) monoclonal antibodies by immunizing animals with three synthetic regional peptides, i.e., the amino terminal (RP-1: N-acetylated 1-19-cysteine), middle portion (RP-2: cysteinyl-91-107) and carboxylic terminal (RP-3: cysteinyl-121-131) regions of human I-FABP, and the whole I-FABP molecule as antigens. We also raised a polyclonal antibody by immunizing with a recombinant (r) I-FABP. To ascertain the specificity of these antibodies for human I-FABP, the immunological reactivity of each was examined by a binding assay using rI-FABP, partially purified native I-FABP and related proteins such as liver-type (L)-FABP, heart-type (H)-FABP, as well as the regional peptides as reactants, and by Western blot analysis. In addition, the expression and distribution of I-FABP in the human gastrointestinal tract were investigated by an immunohistochemical technique using a carboxylic terminal region-specific monoclonal antibody, 8F9, and a polyclonal antibody, DN-R2. Our results indicated that both the monoclonal and polyclonal antibodies established in this study were highly specific for I-FABP, but not for L-FABP and H-FABP. Especially, the monoclonal antibodies raised against the regional peptides, showed regional specificity for the I-FABP molecule. Immunoreactivity of I-FABP was demonstrated in the mucosal epithelium of the jejunum and ileum by immunohistochemical staining, and the immunoreactivity was based on the presence of the whole I-FABP molecule but not the presence of any precursors or degradation products containing a carboxylic terminal fragment. It is concluded that some of these monoclonal and polyclonal antibodies, such as 8F9, 4205, and DN-R2, will be suitable for use in research on the immunochemistry and clinical chemistry of I-FABP because those antibodies can recognize both types of native and denatured I-FABP. In order to detect I-FABP in blood samples, it

  8. Anti-allergic effects of a nonameric peptide isolated from the intestine gastrointestinal digests of abalone (Haliotis discus hannai) in activated HMC-1 human mast cells.

    PubMed

    Ko, Seok-Chun; Lee, Dae-Sung; Park, Won Sun; Yoo, Jong Su; Yim, Mi-Jin; Qian, Zhong-Ji; Lee, Chang-Min; Oh, Junghwan; Jung, Won-Kyo; Choi, Il-Whan

    2016-01-01

    The aim of the present study was to examine whether the intestine gastrointestinal (GI) digests of abalone [Haliotis discus hannai (H. discus hannai)] modulate inflammatory responses and to elucidate the mechanisms involved. The GI digests of the abalone intestines were fractionated into fractions I (>10 kDa), II (5-10 kDa) and Ⅲ (<5 kDa). Of the abalone intestine GI digests (AIGIDs), fraction Ⅲ inhibited the passive cutaneous anaphylaxis (PCA) reaction in mice. Subsequently, a bioactive peptide [abalone intestine GI digest peptide (AIGIDP)] isolated from fraction Ⅲ was determined to be 1175.2 Da, and the amino acid sequence was found to be PFNQGTFAS. We noted that the purified nonameric peptide (AIGIDP) attenuated the phorbol‑12‑myristate 13-acetate plus calcium ionophore A23187 (PMACI)-induced histamine release and the production of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 in human mast cells (HMC-1 cells). In addition, we also noted that AIGIDP inhibited the PMACI‑induced activation of nuclear factor‑κB (NF-κB) by suppressing IκBα phosphorylation and that it suppressed the production of cytokines by decreasing the phosphorylation of JNK. The findings of our study indicate that AIGIDP exerts a modulatory, anti-allergic effect on mast cell-mediated inflammatory diseases.

  9. Utilization of peptide carrier system to improve intestinal absorption: targeting prolidase as a prodrug-converting enzyme

    NASA Technical Reports Server (NTRS)

    Bai, J. P.; Hu, M.; Subramanian, P.; Mosberg, H. I.; Amidon, G. L.

    1992-01-01

    The feasibility of targeting prolidase as a peptide prodrug-converting enzyme has been examined. The enzymatic hydrolysis by prolidase of substrates for the peptide transporter L-alpha-methyldopa-pro and several dipeptide analogues without an N-terminal alpha-amino group (phenylpropionylproline, phenylacetylproline, N-benzoylproline, and N-acetylproline) was investigated. The Michaelis-Menten parameters Km and Vmax for L-alpha-methyldopa-pro are 0.09 +/- 0.02 mM and 3.98 +/- 0.25 mumol/min/mg protein, respectively. However, no hydrolysis of the dipeptide analogues without an N-terminal alpha-amino group is observed, suggesting that an N-terminal alpha-amino group is required for prolidase activity. These results demonstrate that prolidase may serve as a prodrug-converting enzyme for the dipeptide-type prodrugs, utilizing the peptide carrier for transport of prodrugs into the mucosal cells and prolidase, a cytosolic enzyme, to release the drug. However, a free alpha-amino group appears to be necessary for prolidase hydrolysis.

  10. Changes in Sucrase, Enterokinase, and Peptide Hydrolase after Intestinal Resection THE ASSOCIATION OF CELLULAR HYPERPLASIA AND ADAPTATION

    PubMed Central

    McCarthy, Denis M.; Kim, Young S.

    1973-01-01

    In a study of changes in digestive enzymes after massive intestinal resection and the mechanisms by which such changes occur, rats were sacrified 4 wk after removal of the proximal two-thirds of the small intestine. Alterations in the mucosal levels of sucrase, enterokinase, and dipeptide hydrolase (L-leucyl-L-alanine substrate) were examined in the light of associated changes in protein. DNA and wet mucosal weight, measured in standardized gut segments from various regions of intestine. Metabolic studies showed that normal growth patterns were reestablished after the operation but significant elevations in stool weight and fecal nitrogen occurred in the second postoperative week, falling towards normal by the 4th wk. In standard gut segments wet weight of mucosa, protein, and DNA rose, especially in distal segments, DNA increasing disproportionately. Mucosal levels of the proximally distributed and membrane-bound enzymes, sucrase and enterokinase, showed similar patterns of change: when enzyme activity was expressed in terms of the total per segment, proximally there were considerable increases in both enzymes, but, expressed in terms of specific activity, that of sucrase fell and that of enterokinase was unaltered. By contrast, the largely soluble and more distally distributed dipeptide hydrolase increased more in distal segments and the increases in total activity were accompanied by lesser increases in specific activity. However, in spite of increases in total activity, enzyme activity per milligram DNA fell by over 50% in postanastomotic segments. Subcellular distribution studies showed no change in the percentage of the total activity which was membrane-bound and zymograms confirmed that no new dipeptide hydrolase had appeared after resection. It is concluded that increases in the segmental totals of various enzymes seen after resection are achieved by disproportinate increases in the number of mucosal cells per segment and that the greatest change in a

  11. Receptor-Type Protein-Tyrosine Phosphatase ζ and Colony Stimulating Factor-1 Receptor in the Intestine: Cellular Expression and Cytokine- and Chemokine Responses by Interleukin-34 and Colony Stimulating Factor-1

    PubMed Central

    Zwicker, Stephanie; Bureik, Daniela; Bosma, Madeleen; Martinez, Gisele Lago; Almer, Sven

    2016-01-01

    Differential intestinal expression of the macrophage growth factors colony stimulating factor-1 (CSF-1), interleukin (IL)-34, and their shared CSF-1 receptor (CSF-1R) in inflammatory bowel disease (IBD) has been shown. Diverse expression between CSF-1 and IL-34, suggest that IL-34 may signal via an alternate receptor. Receptor-type protein-tyrosine phosphatase ζ (PTPRZ1, RPTP-ζ), an additional IL-34 receptor, was recently identified. Here, we aimed to assess PTPRZ1 expression in IBD and non-IBD intestinal biopsies. Further, we aimed to investigate cellular PTPRZ1 and CSF-1R expression, and cytokine- and chemokine responses by IL-34 and CSF-1. The expression of PTPRZ1 was higher in non-IBD colon compared to ileum. PTPRZ1 expression was not altered with inflammation in IBD, however, correlated to IL34, CSF1, and CSF1R. The expression patterns of PTPRZ1 and CSF-1R differed in peripheral blood mononuclear cells (PBMCs), monocytes, macrophages, and intestinal epithelial cell line. PBMCs and monocytes of the same donors responded differently to IL-34 and CSF-1 with altered expression of tumor-necrosis factor α (TNF-α), IL-1β, interferon γ (IFN-γ), IL-13, IL-8, and monocyte chemotactic protein-1 (MCP-1) levels. This study shows that PTPRZ1 was expressed in bowel tissue. Furthermore, CSF-1R protein was detected in an intestinal epithelial cell line and donor dependently in primary PBMCs, monocytes, and macrophages, and first hints also suggest an expression in these cells for PTPRZ1, which may mediate IL-34 and CSF-1 actions. PMID:27898738

  12. Receptor-Type Protein-Tyrosine Phosphatase ζ and Colony Stimulating Factor-1 Receptor in the Intestine: Cellular Expression and Cytokine- and Chemokine Responses by Interleukin-34 and Colony Stimulating Factor-1.

    PubMed

    Zwicker, Stephanie; Bureik, Daniela; Bosma, Madeleen; Martinez, Gisele Lago; Almer, Sven; Boström, Elisabeth A

    2016-01-01

    Differential intestinal expression of the macrophage growth factors colony stimulating factor-1 (CSF-1), interleukin (IL)-34, and their shared CSF-1 receptor (CSF-1R) in inflammatory bowel disease (IBD) has been shown. Diverse expression between CSF-1 and IL-34, suggest that IL-34 may signal via an alternate receptor. Receptor-type protein-tyrosine phosphatase ζ (PTPRZ1, RPTP-ζ), an additional IL-34 receptor, was recently identified. Here, we aimed to assess PTPRZ1 expression in IBD and non-IBD intestinal biopsies. Further, we aimed to investigate cellular PTPRZ1 and CSF-1R expression, and cytokine- and chemokine responses by IL-34 and CSF-1. The expression of PTPRZ1 was higher in non-IBD colon compared to ileum. PTPRZ1 expression was not altered with inflammation in IBD, however, correlated to IL34, CSF1, and CSF1R. The expression patterns of PTPRZ1 and CSF-1R differed in peripheral blood mononuclear cells (PBMCs), monocytes, macrophages, and intestinal epithelial cell line. PBMCs and monocytes of the same donors responded differently to IL-34 and CSF-1 with altered expression of tumor-necrosis factor α (TNF-α), IL-1β, interferon γ (IFN-γ), IL-13, IL-8, and monocyte chemotactic protein-1 (MCP-1) levels. This study shows that PTPRZ1 was expressed in bowel tissue. Furthermore, CSF-1R protein was detected in an intestinal epithelial cell line and donor dependently in primary PBMCs, monocytes, and macrophages, and first hints also suggest an expression in these cells for PTPRZ1, which may mediate IL-34 and CSF-1 actions.

  13. Glial cell line-derived neurotrophic factor family ligands enhance capsaicin-stimulated release of calcitonin gene-related peptide from sensory neurons.

    PubMed

    Schmutzler, B S; Roy, S; Hingtgen, C M

    2009-06-16

    The glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs) are a group of peptides that have been implicated as important factors in inflammation, since they are released in increased amounts during inflammation and induce thermal hyperalgesia upon injection. Mouse isolated sensory neurons in culture and freshly dissociated spinal cord slices were used to examine the enhancement in stimulated-release of the neuropeptide, calcitonin gene-related peptide (CGRP), as a measure of sensitization. Exposure of isolated sensory neurons in culture to GDNF, neurturin, and artemin enhanced the capsaicin-stimulated release of immunoreactive calcitonin gene-related peptide (iCGRP) two- to threefold, but did not increase potassium-stimulated release of iCGRP. A similar profile of sensitization was observed in freshly dissociated spinal cord slices. Persephin, another member of the GFL family thought to be important in development, was unable to induce an enhancement in the release of iCGRP. These results demonstrate that specific GFLs are important mediators affecting sensory neuronal sensitivity, likely through modulation of the capsaicin receptor. The sensitization of sensory neurons during inflammation, and the pain and neurogenic inflammation resulting from this sensitization, may be due in part to the effects of these selected GFLs.

  14. Selection of multipotent stem cells during morphogenesis of small intestinal crypts of Lieberkuhn is perturbed by stimulation of Lef-1/beta-catenin signaling.

    PubMed

    Wong, Melissa H; Huelsken, Joerg; Birchmeier, Walter; Gordon, Jeffrey I

    2002-05-03

    Studies of chimeric mice have disclosed that the stem cell hierarchy in the small intestinal epithelium is established during formation of its proliferative units (crypts of Lieberkühn). This process involves a selection among several multipotential progenitors so that ultimately only one survives to supply descendants to the fully formed crypt. In this report, we examine the hypothesis that the level of beta-catenin (beta-cat)-mediated signaling is an important factor regulating this stem cell selection. In the canonical Wnt signaling pathway, beta-catenin can partner with Lef-1/Tcf high mobility group (HMG) box transcription factors to control gene expression. Both Lef-1 and Tcf-4 mRNAs are produced in the fetal mouse small intestine. Tcf-4 expression is sustained, whereas Lef-1 levels fall as crypt formation is completed during the first two postnatal weeks. A Tcf-4 gene knockout is known to block intestinal epithelial proliferation in late fetal life. Therefore, to test the hypothesis, we enhanced beta-catenin signaling in a chimeric mouse model in which the stem cell selection could be monitored. A fusion protein containing the HMG box domain of Lef-1 linked to the trans-activation domain of beta-catenin (Lef-1/beta-cat) was constructed to promote direct stimulation of signaling without being retained in the cytoplasm through interactions with E-cadherin and Apc/Axin. Lef-1/beta-cat was expressed in 129/Sv embryonic stem cell-derived small intestinal epithelial progenitors present in developing B6-ROSA26<-->129/Sv chimeras. Lef-1/beta-cat stimulated expression of a known beta-catenin target (E-cadherin), suppressed expression of Apc and Axin, and induced apoptosis in 129/Sv but not in neighboring B6-ROSA26 epithelial cells. This apoptotic response was not associated with any detectable changes in cell division within the Lef-1/beta-cat-expressing epithelium. By the time crypt development was completed, all 129/Sv epithelial cells were lost. These results

  15. Increased Litter Size and Suckling Intensity Stimulate mRNA of RFamide-related Peptide in Rats

    PubMed Central

    Noroozi, Atefeh; Jafarzadeh Shirazi, Mohammad Reza; Tamadon, Amin; Moghadam, Ali; Niazi, Ali

    2015-01-01

    Background RFamide-related peptide-3 (RFRP-3) inhibits gonadotropin releasing hormone (GnRH) and luteinizing hormone (LH) secretion in rats. This study evaluates the effects of litter size and suckling intensity on RFRP mRNA expression in the dorsomedial hypothalamic nucleus (DMH) of rats. Materials and Methods A total of 32 pregnant and 4 non-lactating ovariectomized (control group) Sprague-Dawley rats were used in this experimental study. Lactating rats were allotted to 8 equal groups. In 3 groups, the litter size was adjusted to 5, 10, or 15 pups upon parturition. Dams were allowed to suckle their pups continuously until 8 days postpartum. In the other 3 groups, the litter size was adjusted to 5 pups following birth. These pups were separated from the dams for 6 hours on day 8 postpartum, after which the pups were allowed to suckle for 2.5, 5, or 7.5 minutes prior to killing the dams. In 2 groups, lactating rats with 10 and 15 pups were separated from their pups for 6 hours on day 8 postpartum. In these groups, the pups were allowed to suckle their dams for 5 minutes before the dams were killed. All rats were killed on day 8 postpartum and the DMH was removed from each rat. We evaluated RFRP mRNA expression using realtime polymerase chain reaction (PCR). Results The expression of RFRP mRNA in the DMH increased with increased litter size and suckling intensity compared to the controls. The effect of suckling intensity on the expression of RFRP mRNA was more pronounced compared to the litter size. Conclusion Increased litter size and suckling intensity stimulated RFRP mRNA expression in the DMH which might contribute to lactation anestrus in rats. PMID:26644862

  16. The dietary ingredient, genistein, stimulates cathelicidin antimicrobial peptide expression through a novel S1P-dependent mechanism

    PubMed Central

    Park, Kyungho; Kim, Young-Il; Shin, Kyong-Oh; Seo, Ho Seong; Kim, Jong Youl; Mann, Taj; Oda, Yuko; Lee, Yong-Moon; Holleran, Walter M.; Elias, Peter M.; Uchida, Yoshikazu

    2015-01-01

    We recently discovered that a signaling lipid, sphingosine-1-phosphate (S1P), generated by sphingosine kinase 1, regulates a major epidermal antimicrobial peptide’s [cathelicidin antimicrobial peptide (CAMP)] expression via an NF-κB→C/EBPα-dependent pathway, independent of vitamin D receptor (VDR) in epithelial cells. Activation of estrogen receptors (ER) by either estrogens or phytoestrogens also is known to stimulate S1P production, but it is unknown whether ER activation increases CAMP production. We investigated whether a phytoestrogen, genistein, simulates CAMP expression in keratinocytes, a model of epithelial cells, by either a S1P-dependent mechanism(s) or the alternate VDR-regulated pathway. Exogenous genistein, as well as a ER-β ligand, WAY-200070, increased CAMP mRNA and protein expression in cultured human keratinocytes, while ER-β antagonist, ICI182780, attenuated the expected genistein- and WAY-200070-induced increase in CAMP mRNA/protein expression. Genistein treatment increased acidic and alkaline ceramidase expression and cellular S1P levels in parallel with increased S1P lyase inhibition, accounting for increased CAMP production. In contrast, siRNA against VDR did not alter genistein-mediated upregulation of CAMP. Taken together, genistein induces CAMP production via an ER-β→S1P→NF-κB→C/EBPα-rather than a VDR-dependent mechanism, illuminating a new role for estrogens in the regulation of epithelial innate immunity and pointing to potential additional benefits of dietary genistein in enhancing cutaneous antimicrobial defense. PMID:24768661

  17. Atrial Natriuretic Peptide Stimulates Dopamine Tubular Transport by Organic Cation Transporters: A Novel Mechanism to Enhance Renal Sodium Excretion

    PubMed Central

    Kouyoumdzian, Nicolás M.; Rukavina Mikusic, Natalia L.; Kravetz, María C.; Lee, Brenda M.; Carranza, Andrea; Del Mauro, Julieta S.; Pandolfo, Marcela; Gironacci, Mariela M.; Gorzalczany, Susana; Toblli, Jorge E.; Fernández, Belisario E.

    2016-01-01

    The aim of this study was to demonstrate the effects of atrial natriuretic peptide (ANP) on organic cation transporters (OCTs) expression and activity, and its consequences on dopamine urinary levels, Na+, K+-ATPase activity and renal function. Male Sprague Dawley rats were infused with isotonic saline solution during 120 minutes and randomized in nine different groups: control, pargyline plus tolcapone (P+T), ANP, dopamine (DA), D-22, DA+D-22, ANP+D-22, ANP+DA and ANP+DA+D-22. Renal functional parameters were determined and urinary dopamine concentration was quantified by HPLC. Expression of OCTs and D1-receptor in membrane preparations from renal cortex tissues were determined by western blot and Na+, K+-ATPase activity was determined using in vitro enzyme assay. 3H-DA renal uptake was determined in vitro. Compared to P+T group, ANP and dopamine infusion increased diuresis, urinary sodium and dopamine excretion significantly. These effects were more pronounced in ANP+DA group and reversed by OCTs blockade by D-22, demonstrating that OCTs are implied in ANP stimulated-DA uptake and transport in renal tissues. The activity of Na+, K+-ATPase exhibited a similar fashion when it was measured in the same experimental groups. Although OCTs and D1-receptor protein expression were not modified by ANP, OCTs-dependent-dopamine tubular uptake was increased by ANP through activation of NPR-A receptor and protein kinase G as signaling pathway. This effect was reflected by an increase in urinary dopamine excretion, natriuresis, diuresis and decreased Na+, K+-ATPase activity. OCTs represent a novel target that links the activity of ANP and dopamine together in a common mechanism to enhance their natriuretic and diuretic effects. PMID:27392042

  18. Chronic treatment with the gamma-secretase inhibitor LY-411,575 inhibits beta-amyloid peptide production and alters lymphopoiesis and intestinal cell differentiation.

    PubMed

    Wong, Gwendolyn T; Manfra, Denise; Poulet, Frederique M; Zhang, Qi; Josien, Hubert; Bara, Thomas; Engstrom, Laura; Pinzon-Ortiz, Maria; Fine, Jay S; Lee, Hu-Jung J; Zhang, Lili; Higgins, Guy A; Parker, Eric M

    2004-03-26

    Inhibition of gamma-secretase, one of the enzymes responsible for the cleavage of the amyloid precursor protein (APP) to produce the pathogenic beta-amyloid (Abeta) peptides, is an attractive approach to the treatment of Alzheimer disease. In addition to APP, however, several other gamma-secretase substrates have been identified (e.g. Notch), and altered processing of these substrates by gamma-secretase inhibitors could lead to unintended biological consequences. To study the in vivo consequences of gamma-secretase inhibition, the gamma-secretase inhibitor LY-411,575 was administered to C57BL/6 and TgCRND8 APP transgenic mice for 15 days. Although most tissues were unaffected, doses of LY-411,575 that inhibited Abeta production had marked effects on lymphocyte development and on the intestine. LY-411,575 decreased overall thymic cellularity and impaired intrathymic differentiation at the CD4(-)CD8(-)CD44(+)CD25(+) precursor stage. No effects on peripheral T cell populations were noted following LY-411,575 treatment, but evidence for the altered maturation of peripheral B cells was observed. In the intestine, LY-411,575 treatment increased goblet cell number and drastically altered tissue morphology. These effects of LY-411,575 were not seen in mice that were administered LY-D, a diastereoisomer of LY-411,575, which is a very weak gamma-secretase inhibitor. These studies show that inhibition of gamma-secretase has the expected benefit of reducing Abeta in a murine model of Alzheimer disease but has potentially undesirable biological effects as well, most likely because of the inhibition of Notch processing.

  19. Central pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) decrease the baroreflex sensitivity in trout.

    PubMed

    Lancien, Frédéric; Mimassi, Nagi; Conlon, J Michael; Le Mével, Jean-Claude

    2011-04-01

    Although PACAP and VIP exert diverse actions on heart and blood vessels along the vertebrate phylum, no information is currently available concerning the potential role of these peptides on the regulation of the baroreflex response, a major mechanism for blood pressure homeostasis. Consequently, the goal of this study was to examine in our experimental model, the unanesthetized rainbow trout Oncorhynchus mykiss, whether PACAP and VIP are involved in the regulation of the cardiac baroreflex sensitivity (BRS). Cross-spectral analysis techniques using a fast Fourier transform algorithm were employed to calculate the coherence, phase and gain of the transfer function between spontaneous fluctuations of systolic arterial blood pressure and R-R intervals of the electrocardiogram. The BRS was estimated as the mean of the gain of the transfer function when the coherence between the two signals was high and the phase negative. Compared with vehicle, intracerebroventricular (i.c.v.) injections of trout PACAP-27 and trout VIP (25-100 pmol) dose-dependently reduced the cardiac BRS to the same extent with a threshold dose of 50 pmol for a significant effect. When injected intra-arterially at the same doses as for i.c.v. injections, only the highest dose of VIP (100 pmol) significantly attenuated the BRS. These results suggest that the endogenous peptides PACAP and VIP might be implicated in the central control of cardiac baroreflex functions in trout.

  20. Effects of dietary supplementation with an expressed fusion peptide bovine lactoferricin-lactoferrampin on performance, immune function and intestinal mucosal morphology in piglets weaned at age 21 d.

    PubMed

    Tang, Zhiru; Yin, Yulong; Zhang, Youming; Huang, Ruilin; Sun, Zhihong; Li, Tiejun; Chu, Wuying; Kong, Xiangfeng; Li, Lili; Geng, Meimei; Tu, Qiang

    2009-04-01

    Lactoferrin has antimicrobial activity associated with peptide fragments lactoferricin (LFC) and lactoferrampin (LFA) released on digestion. These two fragments have been expressed in Photorhabdus luminescens as a fusion peptide linked to protein cipB. The construct cipB-LFC-LFA was tested as an alternative to antimicrobial growth promoters in pig production. Sixty piglets with an average live body weight of 5.42 (sem 0.59) kg were challenged with enterotoxigenic Escherichia coli and randomly assigned to four treatment groups fed a maize-soyabean meal diet containing either no addition (C), cipB at 100 mg/kg (C+B), cipB-LFC-LFA at 100 mg/kg (C+L) or colistin sulfate at 100 mg/kg (C+CS) for 3 weeks. Compared with C, dietary supplementation with C+L for 3 weeks increased daily weight gain by 21 %, increased recovery from diarrhoea, enhanced serum glutathione peroxidase (GPx), peroxidase (POD) and total antioxidant content (T-AOC), liver GPx, POD, superoxide dismutase and T-AOC, Fe, total Fe-binding capacity, IgA, IgG and IgM levels (P < 0.05), decreased the concentration of E. coli in the ileum, caecum and colon (P < 0.05), increased the concentration of lactobacilli and bifidobacteria in the ileum, caecum and colon (P < 0.05), and promoted development of the villus-crypt architecture of the small intestine. Growth performance was similar between C+L- and C+CS-supplemented pigs. The present results indicate that LFC-LFA is an effective alternative to the feed antibiotic CS for enhancing growth performance in piglets weaned at age 21 d.

  1. PEGylated porcine glucagon-like peptide-2 improved the intestinal digestive function and prevented inflammation of weaning piglets challenged with LPS.

    PubMed

    Qi, K K; Wu, J; Deng, B; Li, Y M; Xu, Z W

    2015-09-01

    This study was conducted to determine the effects on intestinal function, anti-inflammatory role and possible mechanism of polyethylene glycosylated (PEGylated) porcine glucagon-like peptide-2 (pGLP-2), a long-acting form of pGLP-2, in weaning piglets challenged with Escherichia coli lipopolysaccharide (LPS). We divided 18 weaned piglets on day 21 into three groups (control, LPS and LPS+PEG-pGLP-2; n=6). The piglets from the LPS+PEG-pGLP-2 group were injected with PEG-pGLP-2 at 10 nmol/kg BW from 5 to 7 days of the trials daily. On 8th day, the piglets in the LPS and LPS+PEG-pGLP-2 groups were intraperitoneally administered with 100 µg LPS/kg. The control group was administered with the same volume of saline solution. The piglets were then sacrificed on day 28. Afterwards, serum, duodenum, jejunum and ileum samples were collected for analysis of structural and functional endpoints. LPS+PEG-pGLP-2 treatment increased (P<0.05) lactase activities in the duodenum and the jejunum compared with LPS treatment. LPS+PEG-pGLP-2 treatment also significantly increased sucrase activity in the jejunum compared with LPS treatment. Furthermore, LPS treatment increased (P<0.05) the mRNA expression levels of interleukin (IL)-8, tumour necrosis factor-α (TNF-α) and IL-10 in the ileum compared with the control treatment. By contrast, LPS+PEG-pGLP-2 treatment decreased (P<0.05) the mRNA expression levels of IL-8, IL-10 and TNF-α in the ileum compared with the LPS treatment. LPS treatment also increased (P<0.05) the mRNA expression level of GLP-2 receptor (GLP-2R) and the percentage of GLP-2R-positive cells in the ileum; by comparison, these results were (P<0.05) reduced by LPS+PEG-pGLP-2 treatment. Moreover, LPS+PEG-pGLP-2 treatment increased (P<0.05) the content of serum keratinocyte growth factor compared with the control group and the LPS group. The protective effects of PEG-pGLP-2 on intestinal digestive function were associated with the release of GLP-2R mediator (keratinocyte

  2. Biologically active peptides: prospects for drug development.

    PubMed

    Hughes, J

    1980-08-11

    Biologically active peptides aree typified by their unbiquity of distribution, their high receptor affinity and an almost infinite diversity of structure. For these reasons, considerable effort is now being expended to elucidate the possible role of peptides in brain function. This effort has been stimulated by the discovery of a number of new endogenous peptides, such as the enkephalins, endorphins, vasoactive intestinal peptide and neurotensin. At present, there is no clearly defined role for these peptides, although they may form an important basis for the chemical coding of various brain functions, including pain, mood and memory. At present, the potential for drug development of peptide agonists remains in fairly circumscribed areas such as analgesia, pituitary hormone control, and gastrointestinal motor and secretory control. Peptide antagonists may provide a vast field for future development, although only one area, that of antifertility drugs based on LHRH antagonists, shows any promise of immediate success. Industrial research approaches to new peptide agonists and antagonists mainly rely at present on rational drug design through structural analogies. Other fruitful approaches to be considered are the screening of natural microbial and plant products and the possible application of genetic engineering techniques.

  3. An immunodominant epitope in a functional domain near the N-terminus of human granulocyte-macrophage colony-stimulating factor identified by cross-reaction of synthetic peptides with neutralizing anti-protein and anti-peptide antibodies.

    PubMed

    Beffy, P; Rovero, P; Di Bartolo, V; Laricchia Robbio, L; Dané, A; Pegoraro, S; Bertolero, F; Revoltella, R P

    1994-12-01

    We produced polyclonal and monoclonal antibodies (MAbs) against recombinant human (rh) granulocyte-macrophage colony-stimulating factor (GM-CSF) and performed studies of epitope mapping by ELISA, using five synthetic peptides corresponding to sequences along this molecule. Additionally, anti-peptide MAbs were generated. The antibody ability to inhibit rhGM-CSF activity was determined using as bioassay the MO7e cell line, which is dependent on hGM-CSF for growth in vitro. An immunodominant epitope able to induce the highest neutralization antibody titers was identified near the N terminus of hGM-CSF. A synthetic peptide 14-24, homologous to a sequence including part of the first alpha-helix of the molecule, was recognized by neutralizing anti-protein antibodies. Similarly, MAbs anti- 14-24 cross-reacted with rhGM-CSF and specifically blocked its function. Replacement of Val16 or Asn17 with alanine greatly reduced the antibody-binding capacity to peptide 14-24, whereas substitution of Gln20 or Glu21 was less critical. Monoclonal antibodies generated against residues 30-41 (corresponding to an intrahelical loop) and 79-91 (homologous to a sequence including part of the third alpha-helix) or its analog [Ala88](79-91)beta Ala-Cys, were conformation dependent and nonneutralizing: they failed to react or bound poorly to rhGM-CSF in ELISA, but readily recognized the homologous sequence in the denatured protein, by Western blotting.

  4. Vasoactive intestinal peptide (VIP)-mediated expression and function of steroidogenic acute regulatory protein (StAR) in granulosa cells.

    PubMed

    Kowalewski, Mariusz P; Dyson, Matthew T; Boos, Alois; Stocco, Douglas M

    2010-10-26

    VIP is a peptide hormone capable of activating the cAMP/PKA pathway and modifying gonadal steroidogenic capacity. Less is known about the molecular mechanisms of VIP-mediated steroidogenesis and its role in regulating the steroidogenic acute regulatory protein (STAR). We examined the impact of VIP on STAR expression and function in immortalized (KK1) and primary mouse granulosa cells, where VIP strongly upregulated STAR expression and steroidogenesis. Inhibitors of the PKA and PKC pathways suggested that both are activated by VIP. VIP did not efficiently phosphorylate STAR (P-STAR); however, VIP together with cAMP-analogs that activate Type II PKA increased P-STAR and further increased steroidogenesis. Our results suggest that VIP-induced STAR expression and function in granulosa cells result from the preferential activation of Type I PKA. Furthermore, the PKA and PKC pathways appear to converge at regulating VIP-mediated Star transcription and translation.

  5. Effect of immune system stimulation and divergent selection for residual feed intake on digestive capacity of the small intestine in growing pigs.

    PubMed

    Rakhshandeh, A; Dekkers, J C M; Kerr, B J; Weber, T E; English, J; Gabler, N K

    2012-12-01

    Little is known of the consequences of divergent selection for residual feed intake (RFI) on intestinal digestion capacity, particularly during immune system stimulation (ISS). Our objective was to evaluate the impact of ISS and divergent selection for RFI on apparent ileal digestibility (AID) and apparent fecal digestibility (AFD) of nutrients and intestinal nutrient active transport and barrier function. Twenty-eight gilts (63 ± 4 kg BW) from low RFI (LRFI; n = 14) and high RFI (HRFI; n = 14) Yorkshire lines were randomly selected from the Iowa State University RFI herd. Following adaptation, 8 pigs in each line were injected intramuscularly and every 48 h for 7 d with increasing amounts of Escherichia coli lipopolysaccharide (ISS+). Remaining pigs were injected with saline (ISS-). Pigs were then euthanized and ileal digesta was collected for measuring AID of nutrients. Fecal samples were collected on a daily basis and pooled for measuring AFD of nutrients. A segment of ileum was used to measure nutrient transport and transepithelial resistance (TER) and/or barrier integrity by Ussing chambers. No effects of line or its interaction with ISS on AID of CP (N × 6.25) and OM, TER, and active nutrients transport were observed. However, ISS decreased (P < 0.05) and tended to (P < 0.1) decrease AID of CP and OM, respectively. Decrease in AFD of CP as result of ISS was greater in the LRFI line compared to the HRFI line (P < 0.05). Relative to ISS-, active glucose and P transport was greater in ISS+ pigs (P < 0.05). Genetic selection for LRFI increases the AFD but has no effect on AID of nutrients. It also reduces the total tract digestive capacity of growing pigs during ISS. Immune system stimulation affects both AID and AFD of dietary CP.

  6. Small-molecule activators of TMEM16A, a calcium-activated chloride channel, stimulate epithelial chloride secretion and intestinal contraction

    PubMed Central

    Namkung, Wan; Yao, Zhen; Finkbeiner, Walter E.; Verkman, A. S.

    2011-01-01

    TMEM16A (ANO1) is a calcium-activated chloride channel (CaCC) expressed in secretory epithelia, smooth muscle, and other tissues. Cell-based functional screening of ∼110,000 compounds revealed compounds that activated TMEM16A CaCC conductance without increasing cytoplasmic Ca2+. By patch-clamp, N-aroylaminothiazole “activators” (Eact) strongly increased Cl− current at 0 Ca2+, whereas tetrazolylbenzamide “potentiators” (Fact) were not active at 0 Ca2+ but reduced the EC50 for Ca2+-dependent TMEM16A activation. Of 682 analogs tested, the most potent activator (Eact) and potentiator (Fact) produced large and more sustained CaCC Cl− currents than general agonists of Ca2+ signaling, with EC50 3–6 μM and Cl− conductance comparable to that induced transiently by Ca2+-elevating purinergic agonists. Analogs of activators were identified that fully inhibited TMEM16A Cl− conductance, providing further evidence for direct TMEM16A binding. The TMEM16A activators increased CaCC conductance in human salivary and airway submucosal gland epithelial cells, and IL-4 treated bronchial cells, and stimulated submucosal gland secretion in human bronchi and smooth muscle contraction in mouse intestine. Small-molecule, TMEM16A-targeted activators may be useful for drug therapy of cystic fibrosis, dry mouth, and gastrointestinal hypomotility disorders, and for pharmacological dissection of TMEM16A function.—Namkung, W., Yao, Z., Finkbeiner, W. E., Verkman, A. S. Small-molecule activators of TMEM16A, a calcium-activated chloride channel, stimulate epithelial chloride secretion and intestinal contraction. PMID:21836025

  7. Peripheral nerve reconstruction with epsilon-caprolactone conduits seeded with vasoactive intestinal peptide gene-transfected mesenchymal stem cells in a rat model

    NASA Astrophysics Data System (ADS)

    Hernández-Cortés, P.; Toledo-Romero, M. A.; Delgado, M.; Sánchez-González, C. E.; Martin, F.; Galindo-Moreno, P.; O'Valle, F.

    2014-08-01

    Objective. Attempts have been made to improve nerve conduits in peripheral nerve reconstruction. We investigated the potential therapeutic effect of a vasoactive intestinal peptide (VIP), a neuropeptide with neuroprotective, trophic and developmental regulatory actions, in peripheral nerve regeneration in a severe model of nerve injury that was repaired with nerve conduits. Approach. The sciatic nerve of each male Wistar rat was transected unilaterally at 10 mm and then repaired with Dl-lactic-ɛ-caprolactone conduits. The rats were treated locally with saline, with the VIP, with adipose-derived mesenchymal stem cells (ASCs) or with ASCs that were transduced with the VIP-expressing lentivirus. The rats with the transected nerve, with no repairs, were used as untreated controls. At 12 weeks post-surgery, we assessed their limb function by measuring the ankle stance angle and the percentage of their muscle mass reduction, and we evaluated the histopathology, immunohistochemistry and morphometry of the myelinated fibers. Main results. The rats that received a single injection of VIP-expressing ASCs showed a significant functional recovery in the ankle stance angle (p = 0.049) and a higher number of myelinated fibers in the middle and distal segments of the operated nerve versus the other groups (p = 0.046). Significance. These results suggest that utilization of a cellular substrate, plus a VIP source, is a promising method for enhancing nerve regeneration using Dl-lactic-ɛ-caprolactone conduits and that this method represents a potential useful clinical approach to repairing peripheral nerve damage.

  8. Vasoactive intestinal peptide inhibits liver pathology in acute murine schistosomiasis mansoni and modulates IL-10, IL-12 and TNF-alpha production.

    PubMed

    Allam, Gamal

    2007-01-01

    Vasoactive intestinal peptide (VIP) exerts a broad range of biologic actions that may include modulation of hepatic granuloma formation. This study aimed to investigate the effect of VIP administration on the course of acute murine schistosomiasis mansoni. Mice were infected each with 40 Schistosoma (S.) mansoni cercariae and injected intraperitoneally with VIP at a total dose of 1mug/kg body weight. VIP treatment was very effective in diminishing worm fecundity, hepatic granuloma size and number by about 54%, 75% and 51%, respectively, and reducing liver collagen content. Serum level of interleukin (IL)-10 was increased, while level of IL-12 and tumor necrosis factor (TNF)-alpha were decreased as a result of VIP administration. Carbohydrate antigen 19.9 (CA 19.9) induced by S. mansoni infection was decreased with VIP treatment. Activities of hepatic gamma-glutamyl transferase (gamma-GT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) in liver tissue homogenate of infected treated mice were increased. These results indicate that suitable administration of exogenous VIP can be effective in ameliorating immunopathologic damage associated with schistosomiasis.

  9. In Vitro and Clinical Evaluations of the Drug-Drug Interaction Potential of a Metabotropic Glutamate 2/3 Receptor Agonist Prodrug with Intestinal Peptide Transporter 1

    PubMed Central

    Long, Amanda J.; Annes, William F.; Witcher, Jennifer W.; Knadler, Mary Pat; Ayan-Oshodi, Mosun A.; Mitchell, Malcolm I.; Leese, Phillip; Hillgren, Kathleen M.

    2017-01-01

    Despite peptide transporter 1 (PEPT1) being responsible for the bioavailability for a variety of drugs, there has been little study of its potential involvement in drug-drug interactions. Pomaglumetad methionil, a metabotropic glutamate 2/3 receptor agonist prodrug, utilizes PEPT1 to enhance absorption and bioavailability. In vitro studies were conducted to guide the decision to conduct a clinical drug interaction study and to inform the clinical study design. In vitro investigations determined the prodrug (LY2140023 monohydrate) is a substrate of PEPT1 with Km value of approximately 30 µM, whereas the active moiety (LY404039) is not a PEPT1 substrate. In addition, among the eight known PEPT1 substrates evaluated in vitro, valacyclovir was the most potent inhibitor (IC50 = 0.46 mM) of PEPT1-mediated uptake of the prodrug. Therefore, a clinical drug interaction study was conducted to evaluate the potential interaction between the prodrug and valacyclovir in healthy subjects. No effect of coadministration was observed on the pharmacokinetics of the prodrug, valacyclovir, or either of their active moieties. Although in vitro studies showed potential for the prodrug and valacyclovir interaction via PEPT1, an in vivo study showed no interaction between these two drugs. PEPT1 does not appear to easily saturate because of its high capacity and expression in the intestine. Thus, a clinical interaction at PEPT1 is unlikely even with a compound with high affinity for the transporter. PMID:27895114

  10. Conjugated Alpha-Alumina nanoparticle with vasoactive intestinal peptide as a Nano-drug in treatment of allergic asthma in mice.

    PubMed

    Athari, Seyyed Shamsadin; Pourpak, Zahra; Folkerts, Gert; Garssen, Johan; Moin, Mostafa; Adcock, Ian M; Movassaghi, Masoud; Ardestani, Mehdi Shafiee; Moazzeni, Seyed Mohammad; Mortaz, Esmaeil

    2016-11-15

    Asthma is a chronic respiratory disease characterized by airway inflammation, bronchoconstriction, airway hyperresponsiveness and recurring attacks of impaired breathing. Vasoactive intestinal peptide (VIP) has been proposed as a novel anti-asthma drug due to its effects on airway smooth muscle relaxation, bronchodilation and vasodilation along with its immunomodulatory and anti-inflammatory properties. In the current study, we investigated the therapeutic effects of VIP when conjugated with α-alumina nanoparticle (α-AN) to prevent enzymatic degradation of VIP in the respiratory tract. VIP was conjugated with α-AN. Balb/c mice were sensitized and challenges with ovalbumin (OVA) or PBS and were divided in four groups; VIP-treated, α-AN-treated, α-AN-VIP-treated and beclomethasone-treated as a positive control group. Specific and total IgE level, airway hyperresponsiveness (AHR), bronchial cytokine expression and lung histology were measured. α-AN-VIP significantly reduced the number of eosinophils (Eos), serum IgE level, Th2 cytokines and AHR. These effects of α-AN-VIP were more pronounced than that seen with beclomethasone or VIP alone (P<0.05). The current data indicate that α-AN-VIP can be considered as an effective nano-drug for the treatment of asthma.

  11. 203Pb-Labeled Alpha-Melanocyte-Stimulating Hormone Peptide as an Imaging Probe for Melanoma Detection

    SciTech Connect

    Yubin, Miao; Figueroa, Said D.; Fisher, Darrell R.; Moore, Herbert A.; Testa, Richard F.; Hoffman, Timothy J.; Quinn, Thomas P.

    2008-05-01

    Abbreviations: a-MSH; alpha melanocyte stimulating hormone, DOTA; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, Re(Arg11)CCMSH; DOTA-[Cys3,4,10, D-Phe7, Arg11]a-MSH3-13, NDP; [Nle4,d-Phe7] a-MSH3-13. Abstract Peptide-targeted alpha therapy with 200 mCi of 212Pb-DOTA-Re(Arg11)CCMSH cured 45% of B16/F1 murine melanoma-bearing C57 mice in a 120-day study, highlighting its melanoma treatment potential. However, there is a need to develop an imaging surrogate for patient specific dosimetry and to monitor the tumor response to 212Pb-DOTA-Re(Arg11)CCMSH therapy. The purpose of this study was to evaluate the potential of 203Pb-DOTA-Re(Arg11)CCMSH as a matched-pair SPECT imaging agent for 212Pb-DOTA-Re(Arg11)CCMSH. Method: DOTA-Re(Arg11)CCMSH was labeled with 203Pb in 0.5 M NH4OAc buffer at pH 5.4. The internalization and efflux of 203Pb-DOTA-Re(Arg11)CCMSH were determined in B16/F1 melanoma cells. The pharmacokinetics of 203Pb-DOTA-Re(Arg11)CCMSH were examined in B16/F1 melanoma-bearing C57 mice. A micro-SPECT/CT imaging study was performed with 203Pb-DOTA-Re(Arg11)CCMSH in a B16/F1 melanoma-bearing C57 mouse at 2 h post-injection. Results: 203Pb-DOTA-Re(Arg11)CCMSH was easily prepared in NH4OAc buffer and completely separated from the excess non-radiolabeled peptide by RP-HPLC. 203Pb-DOTA-Re(Arg11)CCMSH displayed fast internalization and extended retention in B16/F1 cells. Approximately 73% of 203Pb-DOTA-Re(Arg11)CCMSH activity internalized after a 20-min incubation at 25C. After incubating the cells in culture media for 20 min, 78% of internalized activity remained in the cells. 203Pb-DOTA-Re(Arg11)CCMSH exhibited similar biodistribution pattern with 212Pb-DOTA-Re(Arg11)CCMSH in B16/F1 melanoma-bearing mice. 203Pb-DOTA-Re(Arg11)CCMSH exhibited the peak tumor uptake of 12.00 +/- 3.20 %ID/g at 1 h post-injection. The tumor uptake gradually decreased to 3.43 +/- 1.12 %ID/g at 48 h post-injection. 203Pb-DOTA-Re(Arg11)CCMSH exhibited the peak tumor to kidney

  12. Isolation and characterization of secretory granules storing a vasoactive intestinal polypeptide-like peptide in Torpedo cholinergic electromotor neurones.

    PubMed

    Agoston, D V; Dowe, G H; Whittaker, V P

    1989-06-01

    Previous immunocytochemical work showed that the cholinergic electromotor neurones of Torpedo marmorata contain a vasoactive intestinal polypeptide-like immunoreactivity (VIPLI) that is conveyed to the terminals by axonal transport from the cell bodies where it is presumably synthesized. In extension of this work, we have now succeeded in isolating the VIPLI storage granules from both the terminals and the axons of these neurones and characterizing them morphologically and biochemically. They were readily separated from synaptic vesicles but contained several components in common that had previously been regarded as specific for synaptic vesicles. Among these were a heparan sulphate type of proteoglycan, synaptophysin, and a Mg2+-dependent ATPase. The VIPLI concentration in lobe tissue and the amount of tissue available were both insufficient to permit the isolation of granules from the electromotor cell bodies by the same technique but it was possible to establish the presence of such granules by particle-exclusion chromatography, using the stable markers mentioned above. In contrast to the VIPLI-containing granules, axonal synaptic vesicles differed from their terminal counterparts in having a very low acetylcholine content relative to stable vesicle markers: they presumably fill up on reaching the terminal where they are exposed to higher concentrations of cytoplasmic acetylcholine.

  13. Multifunctional cyclic D,L-α-peptide architectures stimulate non-insulin dependent glucose uptake in skeletal muscle cells and protect them against oxidative stress.

    PubMed

    Shapira, Renana; Rudnick, Safra; Daniel, Bareket; Viskind, Olga; Aisha, Vered; Richman, Michal; Ayasolla, Kamesh R; Perelman, Alex; Chill, Jordan H; Gruzman, Arie; Rahimipour, Shai

    2013-09-12

    Oxidative stress directly correlates with the early onset of vascular complications and the progression of peripheral insulin resistance in diabetes. Accordingly, exogenous antioxidants augment insulin sensitivity in type 2 diabetic patients and ameliorate its clinical signs. Herein, we explored the unique structural and functional properties of the abiotic cyclic D,L-α-peptide architecture as a new scaffold for developing multifunctional agents to catalytically decompose ROS and stimulate glucose uptake. We showed that His-rich cyclic D,L-α-peptide 1 is very stable under high H2O2 concentrations, effectively self-assembles to peptide nanotubes, and increases the uptake of glucose by increasing the translocation of GLUT1 and GLUT4. It also penetrates cells and protects them against oxidative stress induced under hyperglycemic conditions at a much lower concentration than α-lipoic acid (ALA). In vivo studies are now required to probe the mode of action and efficacy of these abiotic cyclic D,L-α-peptides as a novel class of antihyperglycemic compounds.

  14. Chronic preclinical safety evaluation of EPO-018B, a pegylated peptidic erythropoiesis-stimulating agent in monkeys and rats.

    PubMed

    Gong, Xue-Lian; Gu, Xiao-Lei; Chen, Yong-Chun; Zhu, Hai; Xia, Zhen-Na; Li, Jian-Zhong; Lu, Guo-Cai

    2016-09-15

    EPO-018B, a synthetic peptide-based erythropoiesis stimulating agent (ESA), is mainly designed for treatment of anemia caused by chronic renal failure and chemotherapy against cancer. It overcomes the deficiencies of currently approved ESA, including the frequent administration of temperature-sensitive recombinant protein and anti-EPO antibody-mediated pure red cell aplasia (PRCA). This study was designed to evaluate the potential chronic toxicity of EPO-018B. Subcutaneous administration doses were designed as 0, 0.2, 1 and 10mg/kg for six months for 160 rats (20/gender/group) and 0, 0.3, 3 and 20mg/kg for nine months for 32 monkeys (4/gender/group) once every three weeks. The vehicles received the same volume of physiological saline injection. All animals survived to the scheduled necropsies after six weeks (for rats) and fourteen weeks (for monkeys) recovery period, except for the two high-dose female rats and two high-dose male monkeys, which were considered related to the increased RBCs, chronic blood hyperviscosity and chronic cardiac injury. EPO-018B is supposed to be subcutaneously injected once every month and the intended human therapeutic dose is 0.025mg/kg. The study findings at 0.2mg/kg for rats and 0.3mg/kg for monkeys were considered to be the study NOAEL (the no observed adverse effect level), which were more than ten times the intended human therapeutic dose. Higher doses caused adverse effects related to the liver toxicity, cardiotoxicity, appearance of neutralizing antibodies of EPO-018B and the decrease of serum glucose and cholesterol. Most treatment-induced effects were reversible or revealed ongoing recovery upon the discontinuation of treatment. The sequelae occurred in rats and monkeys were considered secondary to exaggerated pharmacology and would less likely occur in the intended patient population. As to the differences between human beings and animals, the safety of EPO-018B need to be further confirmed in the future clinical studies.

  15. A novel tachykinin NK2 receptor antagonist prevents motility-stimulating effects of neurokinin A in small intestine

    PubMed Central

    Lördal, Mikael; Navalesi, Giovanni; Theodorsson, Elvar; Maggi, Carlo A; Hellström, Per M

    2001-01-01

    MEN 11420 (nepadutant) is a potent, selective and competitive antagonist of tachykinin NK2 receptors. The objective of the present study was to assess the capability of the drug to antagonize the stimulatory effects of neurokinin A (NKA) on gastrointestinal motility, as well as to change the fasting migrating motor complex (MMC). Thirty-four male volunteers were randomized to treatment with either placebo or MEN 11420 in a double-blinded manner. Effects of MEN 11420 (8 mg intravenously) were evaluated as changes in phases I, II and III of MMC, as well as contraction frequency, amplitude and motility index during baseline conditions and during stimulation of motility using NKA (25 pmol kg−1 min−1 intravenously). NKA preceded by placebo increased the fraction of time occupied by phase II, increased contraction frequency, amplitude and motility index. MEN 11420 effectively antagonized the motility-stimulating effects of NKA. MEN 11420 reduced the phase II-stimulating effect of NKA. In addition, the stimulatory effect of NKA on contraction frequency and amplitude, as well as motility index were inhibited by MEN 11420. MEN 11420 did not affect the characteristics of MMC during saline infusion. Plasma levels of MEN 11420 peaked during the first hour after infusion and decreased to less than half during the first 2 h. In conclusion, intravenous MEN 11420 effectively inhibited NKA-stimulated, but not basal gastrointestinal motility, and was well tolerated by all subjects. PMID:11522614

  16. Calcitonin gene-related peptide produces skeletal muscle vasodilation following antidromic stimulation of unmyelinated afferents in the dorsal root in rats.

    PubMed

    Sato, A; Sato, Y; Shimura, M; Uchida, S

    2000-04-07

    In anesthetized rats, the contribution of calcitonin gene-related peptide (CGRP) to antidromic vasodilation of skeletal muscle blood flow (MBF) following electrical stimulation of muscle afferent was investigated by measuring biceps femoris MBF using laser Doppler flowmetry. Repetitive antidromic electrical stimulation of unmyelinated C fibers in ipsilateral dorsal roots at the 3rd-5th lumbar segments for 30 s caused an increase in MBF for 3-15 min (mean 4.5 min) without significant change in systemic arterial blood pressure. The increase in skeletal MBF started about 10 s after the onset of stimulation, and peaked at approximately 130% of the control value at about 30 s after the end of the 30 s period of stimulation. The MBF response was totally abolished by topical application of hCGRP (8-37), a CGRP receptor antagonist. It is concluded that antidromic vasodilation in skeletal muscles following stimulation of unmyelinated C afferents in dorsal roots is independent of systemic blood pressure and is mediated essentially by CGRP. It is suggested that this CGRP-related antidromic vasodilation may be important in the clinical improvement of skeletal MBF produced by physical therapy, e.g. acupuncture.

  17. LPXRFamide peptide stimulates growth hormone and prolactin gene expression during the spawning period in the grass puffer, a semi-lunar synchronized spawner.

    PubMed

    Shahjahan, Md; Doi, Hiroyuki; Ando, Hironori

    2016-02-01

    Gonadotropin-inhibitory hormone (GnIH) plays as a multifunctional neurohormone that controls reproduction in birds and mammals. LPXRFamide (LPXRFa) peptide, the fish ortholog of GnIH, has been shown to regulate the secretion of not only gonadotropin (GTH) but also growth hormone (GH) and prolactin (PRL), which are potentially important for gonadal function. To investigate the role of LPXRFa peptide on reproduction of the grass puffer, which spawns in semilunar cycles, we examined changes in the levels of gh and prl expression over the several months during the reproductive cycle, and the effects of goldfish LPXRFa peptide-1 (gfLPXRFa-1) on their expression were examined using primary pituitary cultures. The expression levels of both gh and prl showed significant changes during the reproductive cycle in both sexes with one peak in the spawning and pre-spawning periods for gh and prl, respectively. Particularly, gh showed substantial increase in expression in the spawning and post-spawning periods, indicative of its essentiality in the advanced stage of reproduction. gfLPXRFa-1 stimulated the expression of both gh and prl but there was a marked difference in response between them: gfLPXRFa-1 stimulated gh expression at a relatively low dose but little effect was observed on prl. Combined with the previous results of daily and circadian oscillations of lpxrfa expression, the present results suggest that LPXRFa peptide is important in the control of the cyclic reproduction by serving as a multifunctional hypophysiotropic factor that regulates the expression of gh and prl as well as GTH subunit genes.

  18. Graphene oxide-stimulated myogenic differentiation of C2C12 cells on PLGA/RGD peptide nanofiber matrices

    NASA Astrophysics Data System (ADS)

    Shin, Y. C.; Lee, J. H.; Kim, M. J.; Hong, S. W.; Oh, J.-W.; Kim, C.-S.; Kim, B.; Hyun, J. K.; Kim, Y.-J.; Han, D.-W.

    2015-07-01

    During the last decade, much attention has been paid to graphene-based nanomaterials because they are considered as potential candidates for biomedical applications such as scaffolds for tissue engineering and substrates for the differentiation of stem cells. Until now, electrospun matrices composed of various biodegradable copolymers have been extensively developed for tissue engineering and regeneration; however, their use in combination with graphene oxide (GO) is novel and challenging. In this study, nanofiber matrices composed of poly(lactic-co-glycolic acid, PLGA) and M13 phage with RGD peptide displayed on its surface (RGD peptide-M13 phage) were prepared as extracellular matrix (ECM)-mimicking substrates. RGD peptide is a tripeptide (Arg-Gly-Asp) found on ECM proteins that promotes various cellular behaviors. The physicochemical properties of PLGA and RGD peptide-M13 phage (PLGA/RGD peptide) nanofiber matrices were characterized by atomic force microscopy, Fourier-transform infrared spectroscopy and thermogravimetric analysis. In addition, the growth of C2C12 mouse myoblasts on the PLGA/RGD peptide matrices was examined by measuring the metabolic activity. Moreover, the differentiation of C2C12 mouse myoblasts on the matrices when treated with GO was evaluated. The cellular behaviors, including growth and differentiation of C2C12 mouse myoblasts, were substantially enhanced on the PLGA/RGD peptide nanofiber matrices when treated with GO. Overall, these findings suggest that the PLGA/RGD peptide nanofiber matrices can be used in combination with GO as a novel strategy for skeletal tissue regeneration.

  19. Leucine Leucine-37 Uses Formyl Peptide Receptor–Like 1 to Activate Signal Transduction Pathways, Stimulate Oncogenic Gene Expression, and Enhance the Invasiveness of Ovarian Cancer Cells

    PubMed Central

    Coffelt, Seth B.; Tomchuck, Suzanne L.; Zwezdaryk, Kevin J.; Danka, Elizabeth S.; Scandurro, Aline B.

    2009-01-01

    Emerging evidence suggests that the antimicrobial peptide, leucine leucine-37 (LL-37), could play a role in the progression of solid tumors. LL-37 is expressed as the COOH terminus of human cationic antimicrobial protein-18 (hCAP-18) in ovarian, breast, and lung cancers. Previous studies have shown that the addition of LL-37 to various cancer cell lines in vitro stimulates proliferation, migration, and invasion. Similarly, overexpression of hCAP-18/LL-37 in vivo accelerates tumor growth. However, the receptor or receptors through which these processes are mediated have not been thoroughly examined. In the present study, expression of formyl peptide receptor–like 1 (FPRL1) was confirmed on ovarian cancer cells. Proliferation assays indicated that LL-37 does not signal through a G protein–coupled receptor, such as FPRL1, to promote cancer cell growth. By contrast, FPRL1 was required for LL-37–induced invasion through Matrigel. The peptide stimulated mitogen-activated protein kinase and Janus-activated kinase/signal transducers and activators of transcription signaling cascades and led to the significant activation of several transcription factors, through both FPRL1-dependent and FPRL1-independent pathways. Likewise, expression of some LL-37–stimulated genes was attenuated by the inhibition of FPRL1. Increased expression of CXCL10, EGF, and PDGF-BB as well as other soluble factors was confirmed from conditioned medium of LL-37–treated cells. Taken together, these data suggest that LL-37 potentiates a more aggressive behavior from ovarian cancer cells through its interaction with FPRL1. PMID:19491199

  20. Leucine leucine-37 uses formyl peptide receptor-like 1 to activate signal transduction pathways, stimulate oncogenic gene expression, and enhance the invasiveness of ovarian cancer cells.

    PubMed

    Coffelt, Seth B; Tomchuck, Suzanne L; Zwezdaryk, Kevin J; Danka, Elizabeth S; Scandurro, Aline B

    2009-06-01

    Emerging evidence suggests that the antimicrobial peptide, leucine leucine-37 (LL-37), could play a role in the progression of solid tumors. LL-37 is expressed as the COOH terminus of human cationic antimicrobial protein-18 (hCAP-18) in ovarian, breast, and lung cancers. Previous studies have shown that the addition of LL-37 to various cancer cell lines in vitro stimulates proliferation, migration, and invasion. Similarly, overexpression of hCAP-18/LL-37 in vivo accelerates tumor growth. However, the receptor or receptors through which these processes are mediated have not been thoroughly examined. In the present study, expression of formyl peptide receptor-like 1 (FPRL1) was confirmed on ovarian cancer cells. Proliferation assays indicated that LL-37 does not signal through a G protein-coupled receptor, such as FPRL1, to promote cancer cell growth. By contrast, FPRL1 was required for LL-37-induced invasion through Matrigel. The peptide stimulated mitogen-activated protein kinase and Janus-activated kinase/signal transducers and activators of transcription signaling cascades and led to the significant activation of several transcription factors, through both FPRL1-dependent and FPRL1-independent pathways. Likewise, expression of some LL-37-stimulated genes was attenuated by the inhibition of FPRL1. Increased expression of CXCL10, EGF, and PDGF-BB as well as other soluble factors was confirmed from conditioned medium of LL-37-treated cells. Taken together, these data suggest that LL-37 potentiates a more aggressive behavior from ovarian cancer cells through its interaction with FPRL1.

  1. Effects of amino acids on melanoma targeting and clearance properties of Tc-99m-labeled Arg-X-Asp-conjugated α-melanocyte stimulating hormone peptides.

    PubMed

    Flook, Adam M; Yang, Jianquan; Miao, Yubin

    2013-11-14

    The purpose of this study was to examine the effects of amino acids on melanoma targeting and clearance properties of new (99m)Tc-labeled Arg-X-Asp-conjugated α-melanocyte stimulating hormone (α-MSH) peptides. RSD-Lys-(Arg(11))CCMSH {c[Arg-Ser-Asp-DTyr-Asp]-Lys-Cys-Cys-Glu-His-dPhe-Arg-Trp-Cys-Arg-Pro-Val-NH2}, RNleD-Lys-(Arg(11))CCMSH, RPheD-Lys-(Arg(11))CCMSH, and RdPheD-Lys-(Arg(11))CCMSH peptides were synthesized and evaluated for their melanocortin-1 (MC1) receptor binding affinities in B16/F1 melanoma cells. The biodistribution of (99m)Tc-RSD-Lys-(Arg(11))CCMSH, (99m)Tc-RFD-Lys-(Arg(11))CCMSH, and (99m)Tc-RfD-Lys-(Arg(11))CCMSH were determined in B16/F1 melanoma-bearing C57 mice. The substitution of Gly with Ser, Phe, and dPhe increased the MC1 receptor binding affinities of the peptides, whereas the substitution of Gly with Nle decreased the MC1 receptor binding affinity of the peptide. (99m)Tc-RSD-Lys-(Arg(11))CCMSH exhibited the highest melanoma uptake (18.01 ± 4.22% ID/g) and the lowest kidney and liver uptake among these (99m)Tc-peptides. The B16/F1 melanoma lesions could be clearly visualized by SPECT/CT using (99m)Tc-RSD-Lys-(Arg(11))CCMSH as an imaging probe. It is desirable to reduce the renal uptake of (99m)Tc-RSD-Lys-(Arg(11))CCMSH to facilitate its potential therapeutic application.

  2. Campylobacter jejuni carbon starvation protein A (CstA) is involved in peptide utilization, motility and agglutination, and has a role in stimulation of dendritic cells.

    PubMed

    Rasmussen, J J; Vegge, C S; Frøkiær, H; Howlett, R M; Krogfelt, K A; Kelly, D J; Ingmer, H

    2013-08-01

    Campylobacter jejuni is the most frequent cause of severe gastroenteritis in the developed world. The major symptom of campylobacteriosis is inflammatory diarrhoea. The molecular mechanisms of this infection are poorly understood compared to those of less frequent disease-causing pathogens. In a previous study, we identified C. jejuni proteins that antibodies in human campylobacteriosis patients reacted with. One of the immunogenic proteins identified (Cj0917) displays homology to carbon starvation protein A (CstA) from Escherichia coli, where this protein is involved in the starvation response and peptide uptake. In contrast to many bacteria, C. jejuni relies on amino acids and organic acids for energy, but in vivo it is highly likely that peptides are also utilized, although their mechanisms of uptake are unknown. In this study, Biolog phenotype microarrays have been used to show that a ΔcstA mutant has a reduced ability to utilize a number of di- and tri-peptides as nitrogen sources. This phenotype was restored through genetic complementation, suggesting CstA is a peptide uptake system in C. jejuni. Furthermore, the ΔcstA mutant also displayed reduced motility and reduced agglutination compared to WT bacteria; these phenotypes were also restored through complementation. Murine dendritic cells exposed to UV-killed bacteria showed a reduced IL-12 production, but the same IL-10 response when encountering C. jejuni ΔcstA compared to the WT strain. The greater Th1 stimulation elicited by the WT as compared to ΔcstA mutant cells indicates an altered antigenic presentation on the surface, and thus an altered recognition of the mutant. Thus, we conclude that C. jejuni CstA is important not only for peptide utilization, but also it may influence host-pathogen interactions.

  3. Enteral nutrients potentiate glucagon-like peptide-2 action and reduce dependence on parenteral nutrition in a rat model of human intestinal failure.

    PubMed

    Brinkman, Adam S; Murali, Sangita G; Hitt, Stacy; Solverson, Patrick M; Holst, Jens J; Ney, Denise M

    2012-09-01

    Glucagon-like peptide-2 (GLP-2) is a nutrient-dependent, proglucagon-derived gut hormone that shows promise for the treatment of short bowel syndrome (SBS). Our objective was to investigate how combination GLP-2 + enteral nutrients (EN) affects intestinal adaption in a rat model that mimics severe human SBS and requires parenteral nutrition (PN). Male Sprague-Dawley rats were assigned to one of five groups and maintained with PN for 18 days: total parenteral nutrition (TPN) alone, TPN + GLP-2 (100 μg·kg(-1)·day(-1)), PN + EN + GLP-2(7 days), PN + EN + GLP-2(18 days), and a nonsurgical oral reference group. Animals underwent massive distal bowel resection followed by jejunocolic anastomosis and placement of jugular catheters. Starting on postoperative day 4, rats in the EN groups were allowed ad libitum access to EN. Groups provided PN + EN + GLP-2 had their rate of PN reduced by 0.25 ml/day starting on postoperative day 6. Groups provided PN + EN + GLP-2 demonstrated significantly greater body weight gain with similar energy intake and a safe 80% reduction in PN compared with TPN ± GLP-2. Groups provided PN + EN + GLP-2 for 7 or 18 days showed similar body weight gain, residual jejunal length, and digestive capacity. Groups provided PN + EN + GLP-2 showed increased jejunal GLP-2 receptor (GLP-2R), insulin-like growth factor-I (IGF-I), and IGF-binding protein-5 (IGFBP-5) expression. Treatment with TPN + GLP-2 demonstrated increased jejunal expression of epidermal growth factor. Cessation of GLP-2 after 7 days with continued EN sustained the majority of intestinal adaption and significantly increased expression of colonic proglucagon compared with PN + EN + GLP-2 for 18 days, and increased plasma GLP-2 concentrations compared with TPN alone. In summary, EN potentiate the intestinotrophic actions of GLP-2 by improving body weight gain allowing for a safe 80% reduction in PN with increased jejunal expression of GLP-2R, IGF-I, and IGFBP-5 following distal bowel

  4. Enteral nutrients potentiate glucagon-like peptide-2 action and reduce dependence on parenteral nutrition in a rat model of human intestinal failure

    PubMed Central

    Brinkman, Adam S.; Murali, Sangita G.; Hitt, Stacy; Solverson, Patrick M.; Holst, Jens J.

    2012-01-01

    Glucagon-like peptide-2 (GLP-2) is a nutrient-dependent, proglucagon-derived gut hormone that shows promise for the treatment of short bowel syndrome (SBS). Our objective was to investigate how combination GLP-2 + enteral nutrients (EN) affects intestinal adaption in a rat model that mimics severe human SBS and requires parenteral nutrition (PN). Male Sprague-Dawley rats were assigned to one of five groups and maintained with PN for 18 days: total parenteral nutrition (TPN) alone, TPN + GLP-2 (100 μg·kg−1·day−1), PN + EN + GLP-2(7 days), PN + EN + GLP-2(18 days), and a nonsurgical oral reference group. Animals underwent massive distal bowel resection followed by jejunocolic anastomosis and placement of jugular catheters. Starting on postoperative day 4, rats in the EN groups were allowed ad libitum access to EN. Groups provided PN + EN + GLP-2 had their rate of PN reduced by 0.25 ml/day starting on postoperative day 6. Groups provided PN + EN + GLP-2 demonstrated significantly greater body weight gain with similar energy intake and a safe 80% reduction in PN compared with TPN ± GLP-2. Groups provided PN + EN + GLP-2 for 7 or 18 days showed similar body weight gain, residual jejunal length, and digestive capacity. Groups provided PN + EN + GLP-2 showed increased jejunal GLP-2 receptor (GLP-2R), insulin-like growth factor-I (IGF-I), and IGF-binding protein-5 (IGFBP-5) expression. Treatment with TPN + GLP-2 demonstrated increased jejunal expression of epidermal growth factor. Cessation of GLP-2 after 7 days with continued EN sustained the majority of intestinal adaption and significantly increased expression of colonic proglucagon compared with PN + EN + GLP-2 for 18 days, and increased plasma GLP-2 concentrations compared with TPN alone. In summary, EN potentiate the intestinotrophic actions of GLP-2 by improving body weight gain allowing for a safe 80% reduction in PN with increased jejunal expression of GLP-2R, IGF-I, and IGFBP-5 following distal bowel

  5. The role of glucagon-like peptide-2 on apoptosis, cell proliferation, and oxidant-antioxidant system at a mouse model of intestinal injury induced by tumor necrosis factor-alpha/actinomycin D.

    PubMed

    Arda-Pirincci, Pelin; Bolkent, Sehnaz

    2011-04-01

    Tumor necrosis factor-alpha (TNF-α) is a multifunctional cytokine, which has the ability to produce cytotoxicity via induction of cell death and cell cycle arrest. Blocking the synthesis of protective proteins through a transcriptional inhibitor such as actinomycin D (Act D) sensitizes many cell types to TNF-α toxicity. Teduglutide, h[Gly(2)]GLP-2, is a protease-resistant synthetic analog of glucagon-like peptide-2 (GLP-2) which is an intestinotrophic peptide. In this study, we evaluated this potential of GLP-2 on apoptosis, cell proliferation, and oxidant-antioxidant system on a mouse model of intestinal injury induced by TNF-α/Act D. The intestinal injury was induced by intraperitoneal administration of 15 μg/kg TNF-α and 800 μg/kg Act D per mouse. Animals were injected subcutaneously 200 μg/kg h[Gly(2)]GLP-2 every 12 h for 10 consecutive days prior to the administration of TNF-α and Act D. The model of intestinal injury induced by TNF-α/Act D, which is the new animal model for the intestinal disorders, was characterized by the degeneration of intestinal mucosa, an increase in apoptotic index, expression of active caspase-3, lipid peroxidation and glutathione (GSH) levels, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities; a decrease in cell proliferation and catalase (CAT) activity. h[Gly(2)]GLP-2 pretreatment prevented the TNF-α/Act D-induced oxidative injury by a significant reduction in the intestinal injury, apoptotic index, expression of active caspase-3, lipid peroxidation and GSH levels, GPx and SOD activities; a markedly increase in cell proliferation, and CAT activity. These results demonstrate that GLP-2 has a protective, antiapoptotic, proliferative, and antioxidant effects against to TNF-α/Act D-induced intestinal injury. It is suggested that GLP-2 may potentially be useful as a therapeutic agent in TNF-α-mediated intestinal disorders.

  6. Statins promote the degradation of extracellular amyloid {beta}-peptide by microglia via stimulation of exosome-associated insulin-degrading enzyme (IDE) secretion.

    PubMed

    Tamboli, Irfan Y; Barth, Esther; Christian, Leonie; Siepmann, Martin; Kumar, Sathish; Singh, Sandesh; Tolksdorf, Karen; Heneka, Michael T; Lütjohann, Dieter; Wunderlich, Patrick; Walter, Jochen

    2010-11-26

    Epidemiological studies indicate that intake of statins decrease the risk of developing Alzheimer disease. Cellular and in vivo studies suggested that statins might decrease the generation of the amyloid β-peptide (Aβ) from the β-amyloid precursor protein. Here, we show that statins potently stimulate the degradation of extracellular Aβ by microglia. The statin-dependent clearance of extracellular Aβ is mainly exerted by insulin-degrading enzyme (IDE) that is secreted in a nonconventional pathway in association with exosomes. Stimulated IDE secretion and Aβ degradation were also observed in blood of mice upon peripheral treatment with lovastatin. Importantly, increased IDE secretion upon lovastatin treatment was dependent on protein isoprenylation and up-regulation of exosome secretion by fusion of multivesicular bodies with the plasma membrane. These data demonstrate a novel pathway for the nonconventional secretion of IDE via exosomes. The modulation of this pathway could provide a new strategy to enhance the extracellular clearance of Aβ.

  7. The Anorexigenic Peptide Neuromedin U (NMU) Attenuates Amphetamine-Induced Locomotor Stimulation, Accumbal Dopamine Release and Expression of Conditioned Place Preference in Mice

    PubMed Central

    Vallöf, Daniel; Vestlund, Jesper; Engel, Jörgen A.; Jerlhag, Elisabet

    2016-01-01

    Amphetamine dependence, besides its substantial economical consequence, is a serious cause of mortality and morbidity. By investigations of the neurochemical correlates through which addictive drugs, such as amphetamine, activate the mesoaccumbal dopamine system unique targets for treatment of drug addiction can be identified. This reward link consists of a dopamine projection from the ventral tegmental area to the nucleus accumbens (NAc) suggesting that these brain areas are important for reward. The physiological function of gut-brain peptides has expanded beyond food intake modulation and involves regulation of drug reinforcement. A novel candidate for reward regulation is the anorexigenic peptide neuromedin U (NMU). We therefore investigated the effects of intracerebroventricular (icv) administration of NMU on amphetamine’s well-documented effects on the mesoaccumbal dopamine system, i.e. locomotor stimulation and accumbal dopamine release in mice. In addition, the effect of accumbal NMU administration on locomotor activity was examined. The effect of NMU, icv or intra-NAc, on the expression of conditioned place preference (CPP) was elucidated. Firstly, we showed that icv administration of NMU attenuate the amphetamine-induced locomotor stimulation, accumbal dopamine release and expression of CPP in mice. Secondly, we found that a lower dose of NMU (icv) reduce the amphetamine-induced locomotor stimulation in mice. Thirdly, we demonstrated that NMU administration into the NAc block the ability of amphetamine to cause a locomotor stimulation in mice. However, accumbal NMU administration did not attenuate the amphetamine-induced expression of CPP in mice. Our novel data suggest that central NMU signalling is involved in development of amphetamine dependence. PMID:27139195

  8. The human vasoactive intestinal peptide/pituitary adenylate cyclase-activating peptide receptor 1 (VPAC1) promoter: characterization and role in receptor expression during enterocytic differentiation of the colon cancer cell line Caco-2Cl.20.

    PubMed Central

    Couvineau, A; Maoret, J J; Rouyer-Fessard, C; Carrero, I; Laburthe, M

    2000-01-01

    The basic organization of the human vasoactive intestinal peptide/pituitary adenylate cyclase-activating peptide receptor (VPAC) 1 promoter was investigated after cloning the 5'-flanking region (1.4 kb) of the VPAC1 gene from a human genomic library. Subsequent functional analysis of various deletions of the 5'-flanking sequence, subcloned upstream of a luciferase reporter gene, was carried out in HT-29 cells. The minimal promoter region identified encompasses the -205/+76 sequence and contains a crucial CCAAT box (-182/-178) and a GC-rich sequence. Moreover a region (-1348/-933) containing a silencer element was identified. We previously showed that the expression of the VPAC1 receptor binding site is strictly dependent upon the enterocytic differentiation of human colon cancer Caco-2 cells [Laburthe, Rousset, Rouyer-Fessard, Couvineau, Chantret, Chevalier and Zweibaum (1987) J. Biol. Chem. 262, 10180-10184]. In the present study we show that VPAC1 mRNA increases dramatically when Caco-2Cl.20 cells differentiate, as measured by RNase protection assays and reverse transcriptase-PCR. A single transcript species of 3 kb is detected in differentiated cells by Northern-blot analysis. Accumulation of VPAC1 receptor mRNA is due to a 5-fold increase of transcription rate (run-on assay) without a change in mRNA half-life (9 h). Stable transfections of various constructs in Caco-2Cl.20 cells and subsequent analysis of reporter gene expression, during the enterocytic differentiation process over 25 days of culture, further indicated that the -254/+76 5'-flanking sequence is endowed with the regulatory element(s) necessary for transcriptional regulation of VPAC1 during differentiation. Altogether, these observations provide the first characterization of the basic organization of the human VPAC1 gene promoter and unravel the crucial role of a short promoter sequence in the strict transcriptional control of VPAC1 expression during differentiation of human colon cancer Caco-2

  9. GLP-2 potentiates L-type CA2+ channel activity associated with stimulated glucose uptake in hippocampal neurons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glucagon-like peptide-2 (GLP-2) is a neuropeptide secreted from endocrine cells in the gut and neurons in the brain. GLP-2 stimulates intestinal crypt cell proliferation and mucosal blood flow while decreasing gastric emptying and gut motility. However, a GLP-2-mediated signaling network has not bee...

  10. Free fatty acids stimulate the polymerization of tau and amyloid beta peptides. In vitro evidence for a common effector of pathogenesis in Alzheimer's disease.

    PubMed Central

    Wilson, D. M.; Binder, L. I.

    1997-01-01

    Alzheimer's disease is a degenerative disorder of the central nervous system, characterized by the concomitant deposition of extracellular filaments composed of beta-amyloid peptides and intracellular filaments composed of the microtubule-associated protein tau. We have discovered that free fatty acids (FFAs) stimulate the assembly of both amyloid and tau filaments in vitro. The minimal concentration of arachidonic acid observed to stimulate tau assembly ranged from 10 to 20 mumol/L, depending on the source of the purified tau. Tau preparations that do not exhibit spontaneous assembly were among those induced to polymerize by arachidonic acid. All long-chain FFAs tested enhanced assembly to some extent, although greater stimulation was usually associated with unsaturated forms. Utilizing fluorescence spectroscopy, unsaturated FFAs were also demonstrated to induce beta-amyloid assembly. The minimal concentration of oleic or linoleic acid observed to stimulate the assembly of amyloid was 40 mumol/L. The filamentous nature of these thioflavin-binding amyloid polymers was verified by electron microscopy. These data define a new set of tools for examining the polymerization of amyloid and tau proteins and suggest that cortical elevations of FFAs may constitute a unifying stimulatory event driving the formation of two of the obvious pathogenetic lesions in Alzheimer's disease. Images Figure 2 Figure 4 PMID:9176408

  11. Brevinin-2-related peptide and its [D4K] analogue stimulate insulin release in vitro and improve glucose tolerance in mice fed a high fat diet.

    PubMed

    Abdel-Wahab, Y H A; Patterson, S; Flatt, P R; Conlon, J M

    2010-08-01

    The cationic, alpha-helical frog skin antimicrobial peptide B2RP (brevinin-2-related peptide) shows sequence similarity to antimicrobial peptides belonging to the brevinin-2 family, but lacks the C-terminal cyclic heptapeptide domain (Cys-Lys-Xaa (4)-Cys). Synthetic B2RP produced a significant (p<0.05) stimulation of insulin release (148% of basal rate at a concentration of 1 muM with a maximum response of 222% of basal rate at a concentration of 3 muM) from BRIN-BD11 clonal beta-cells without increasing the release of the cytosolic enzyme, lactate dehydrogenase. Increasing cationicity of B2RP while maintaining amphipathicity by the substitution Asp (4) --> Lys enhanced the insulin-releasing potency (137% of basal rate at a concentration of 0.3 muM; p<0.05) with no stimulation of lactate dehydrogenase release. In contrast, the L18K, and D4K, L18K analogues were toxic to the cells, and the K16A analogue, with increased amphipathicity and hydrophobicity, showed reduced potency. Administration of [D4K]B2RP (100 nmol/kg body weight) to mice fed a high fat diet to induce obesity and insulin-resistance significantly (p<0.05) enhanced insulin release and improved glucose tolerance during the 60-minute period following an intraperitoneal glucose load (18 mmol/kg body weight). B2RP shows potential for development into an agent for the treatment of type 2 diabetes.

  12. Both direct and indirect effects account for the pro-inflammatory activity of enteropathogenic mycotoxins on the human intestinal epithelium: Stimulation of interleukin-8 secretion, potentiation of interleukin-1{beta} effect and increase in the transepithelial passage of commensal bacteria

    SciTech Connect

    Maresca, Marc; Yahi, Nouara; Younes-Sakr, Lama; Boyron, Marilyn; Caporiccio, Bertrand; Fantini, Jacques

    2008-04-01

    Mycotoxins are fungal secondary metabolites responsible of food-mediated intoxication in animals and humans. Deoxynivalenol, ochratoxin A and patulin are the best known enteropathogenic mycotoxins able to alter intestinal functions resulting in malnutrition, diarrhea, vomiting and intestinal inflammation in vivo. Although their effects on intestinal barrier and transport activities have been extensively characterized, the mechanisms responsible for their pro-inflammatory effect are still poorly understood. Here we investigated if mycotoxin-induced intestinal inflammation results from a direct and/or indirect pro-inflammatory activity of these mycotoxins on human intestinal epithelial cells, using differentiated Caco-2 cells as model and interleukin 8 (IL-8) as an indicator of intestinal inflammation. Deoxynivalenol was the only mycotoxin able to directly increase IL-8 secretion (10- to 15-fold increase). We also investigated if these mycotoxins could indirectly stimulate IL-8 secretion through: (i) a modulation of the action of pro-inflammatory molecules such as the interleukin-1beta (IL-1{beta}), and/or (ii) an increase in the transepithelial passage of non-invasive commensal Escherichia coli. We found that deoxynivalenol, ochratoxin A and patulin all potentiated the effect of IL-1{beta} on IL-8 secretion (ranging from 35% to 138% increase) and increased the transepithelial passage of commensal bacteria (ranging from 12- to 1544-fold increase). In addition to potentially exacerbate established intestinal inflammation, these mycotoxins may thus participate in the induction of sepsis and intestinal inflammation in vivo. Taken together, our results suggest that the pro-inflammatory activity of enteropathogenic mycotoxins is mediated by both direct and indirect effects.

  13. Melanoma targeting with [(99m)Tc(N)(PNP3)]-labeled α-melanocyte stimulating hormone peptide analogs: Effects of cyclization on the radiopharmaceutical properties.

    PubMed

    Carta, Davide; Salvarese, Nicola; Morellato, Nicolò; Gao, Feng; Sihver, Wiebke; Pietzsch, Hans Jurgen; Biondi, Barbara; Ruzza, Paolo; Refosco, Fiorenzo; Carpanese, Debora; Rosato, Antonio; Bolzati, Cristina

    2016-12-01

    The purpose of this study was to evaluate the effect of cyclization on the biological profile of a [(99m)Tc(N)(PNP3)]-labeled α-melanocyte stimulating hormone peptide analog. A lactam bridge-cyclized H-Cys-Ahx-βAla(3)-c[Lys(4)-Glu-His-D-Phe-Arg-Trp-Glu(10)]-Arg(11)-Pro-Val-NH2 (NAP-NS2) and the corresponding linear H-Cys-Ahx-βAla-Nle-Asp-His-D-Phe-Arg-Trp-Gly-NH2 (NAP-NS1) peptide were synthetized, characterized by ESI-MS spectroscopy and their melanocortin-1 receptor (MC1R) binding affinity was determined in B16/F10 melanoma cells. The consistent [(99m)Tc(N)(PNP3)]-labeled compounds were readily obtained in high specific activity and their stability and biological properties were assessed. As an example, the chemical identity of [(99m)Tc(N)(NAP-NS1)(PNP3)](+) was confirmed by carrier added experiments supported by radio/UV HPLC analysis combined with ESI(+)-MS. Compared with the linear peptide, cyclization negatively affected the biological properties of NAP-NS2 peptide by reducing its binding affinity for MC1R and by decreasing the overall excretion rate of the corresponding [(99m)Tc(N)(PNP3)]-labeled peptide from the body as well as its in vivo stability. [(99m)Tc(N)(NAP-NS1)(PNP3)](+) was evaluated for its potential as melanoma imaging probe in murine melanoma model. Data from in vitro and in vivo studies on B16/F10 melanoma model of [(99m)Tc(N)(NAP-NS1)(PNP3)](+) clearly evidenced that the radiolabeled linear peptide keeps its biological properties up on the conjugation to the [(99m)Tc(N)(PNP3)]-building block. The progressive increase of the tumor-to-nontarget ratios over the time indicates a quite stable interaction between the radio-complex and the MC1R.

  14. [The association of intestinal microbiota with obesity].

    PubMed

    Morales, Pamela; Brignardello, Jerusa; Gotteland, Martín

    2010-08-01

    Intestinal microbiota (IM) plays a role in the development of obesity and its associated low grade inflammation. Bacterial colonization of the gastrointestinal tract of germ free mice (without microbiota) increases by 60% their fat mass, alters their fasting glucose and insulin levels, triples their hepatic triglycerides and induces adipocyte hypertrophy. IM favors fat storage in adipocytes through the inhibition of Fiaf (Fasting Induced Adipocyte Factor), an inhibitor of lipoprotein lipase. Compared with normal weight subjects, the IM from obese exhibits a higher proportion of Firmicutes/Bacteroidetes and is more efficient in extracting energy from foodstuffs. The loss of bodyweight by a hypocaloric diet reverts the proportion of bacteria to that of lean subjects. The intake of a high fat diet also alters the IM, affecting intestinal barrier function and favoring endotoxinemia. These events increase oxidative and pro-inflammatory processes in plasma and peripheral tissues and increment the risk of insulin resistance. Such events are reverted by the administration of prebiotics which stimulate the growth of Bifdobacterium and Lactobacillus species in the colon, reestablishing the gut homeostasis. Interestingly, products resulting from the fermentation of prebiotics stimulate the differentiation of enteroendocrine cells and the release of glucagon like peptide 1 and peptide YY, that have insulin like and anorexigenic activities, thus contributing to body weight equilibrium.

  15. Effect of a calcitonin gene-related peptide antagonist (CGRP8-37) on skin vasodilatation and oedema induced by stimulation of the rat saphenous nerve.

    PubMed Central

    Escott, K. J.; Brain, S. D.

    1993-01-01

    1. The effect of the calcitonin gene-related peptide antagonist (CGRP8-37, 400 nmol kg-1, i.v.) on the increased blood flow induced by calcitonin gene related peptide (CGRP), vasodilator prostaglandins, and topical capsaicin was measured with a laser Doppler blood flow meter in rat abdominal skin. 2. The saphenous nerve was electrically stimulated and the effect of CGRP8-37 (400 nmol kg-1, i.v.) on the increased blood flow (measured by laser Doppler flowmetry) and oedema formation (measured by the extravascular accumulation of [125I]-albumin) was investigated in the rat hind paw. 3. CGRP8-37 (400 nmol kg-1, i.v.) had no effect on basal cutaneous blood flow at uninjected sites and sites injected with Tyrode buffer, but acted selectively to inhibit the increased blood flow induced by intradermal CGRP (10 pmol/site, P < 0.05), but not that induced by prostaglandin E2 (PGE2, 300 pmol/site) or carba-prostacyclin (cPGI2, 100 pmol/site). 4. Capsaicin (0.1-33 mM), applied topically, acted in a dose-related manner to increase blood flow. CGRP8-37 (400 nmol kg-1, i.v.) almost totally inhibited blood flow induced by capsaicin (10 mM; P < 0.05) but did not significantly inhibit blood flow induced by a higher dose of capsaicin (33 mM). 5. The increased blood flow induced by short stimulation of the saphenous nerve (10 V, 1 ms, 2 Hz for 30 s) was inhibited by 76%, 5 min after i.v. CGRP8-37 (400 nmol kg-1, i.v., P < 0.05). 6. A longer (5 min) electrical stimulation of the saphenous nerve caused oedema formation, in addition to increased blood flow.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8242250

  16. Prenatal exposure to ethanol stimulates hypothalamic CCR2 chemokine receptor system: Possible relation to increased density of orexigenic peptide neurons and ethanol drinking in adolescent offspring.

    PubMed

    Chang, G-Q; Karatayev, O; Leibowitz, S F

    2015-12-03

    Clinical and animal studies indicate that maternal consumption of ethanol during pregnancy increases alcohol drinking in the offspring. Possible underlying mechanisms may involve orexigenic peptides, which are stimulated by prenatal ethanol exposure and themselves promote drinking. Building on evidence that ethanol stimulates neuroimmune factors such as the chemokine CCL2 that in adult rats is shown to colocalize with the orexigenic peptide, melanin-concentrating hormone (MCH) in the lateral hypothalamus (LH), the present study sought to investigate the possibility that CCL2 or its receptor CCR2 in LH is stimulated by prenatal ethanol exposure, perhaps specifically within MCH neurons. Our paradigm of intraoral administration of ethanol to pregnant rats, at low-to-moderate doses (1 or 3g/kg/day) during peak hypothalamic neurogenesis, caused in adolescent male offspring twofold increase in drinking of and preference for ethanol and reinstatement of ethanol drinking in a two-bottle choice paradigm under an intermittent access schedule. This effect of prenatal ethanol exposure was associated with an increased expression of MCH and density of MCH(+) neurons in LH of preadolescent offspring. Whereas CCL2(+) cells at this age were low in density and unaffected by ethanol, CCR2(+) cells were dense in LH and increased by prenatal ethanol, with a large percentage (83-87%) identified as neurons and found to colocalize MCH. Prenatal ethanol also stimulated the genesis of CCR2(+) and MCH(+) neurons in the embryo, which co-labeled the proliferation marker, BrdU. Ethanol also increased the genesis and density of neurons that co-expressed CCR2 and MCH in LH, with triple-labeled CCR2(+)/MCH(+)/BrdU(+) neurons that were absent in control rats accounting for 35% of newly generated neurons in ethanol-exposed rats. With both the chemokine and MCH systems believed to promote ethanol consumption, this greater density of CCR2(+)/MCH(+) neurons in the LH of preadolescent rats suggests that

  17. eNOS signaling is essential in GLP-2-mediated stimulation of blood flow, but not cell proliferation in the mouse gut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Through a G protein-coupled receptor, glucagon-like peptide-2 (GLP-2) stimulates intestinal crypt cell proliferation and mucosal blood flow. GLP-2 receptor is localized to enteric neurons, endocrine cells, and myofibroblasts, but not enterocytes. However, it is largely unknown how GLP-2 receptor-act...

  18. Supra-molecular assembly of a lumican-derived peptide amphiphile enhances its collagen-stimulating activity.

    PubMed

    Walter, Merlin N M; Dehsorkhi, Ashkan; Hamley, Ian W; Connon, Che J

    2016-02-01

    C16-YEALRVANEVTLN, a peptide amphiphile (PA) incorporating a biologically active amino acid sequence found in lumican, has been examined for its influence upon collagen synthesis by human corneal fibroblasts in vitro, and the roles of supra-molecular assembly and activin receptor-like kinase ALK receptor signaling in this effect were assessed. Cell viability was monitored using the Alamar blue assay, and collagen synthesis was assessed using Sirius red. The role of ALK signaling was studied by receptor inhibition. Cultured human corneal fibroblasts synthesized significantly greater amounts of collagen in the presence of the PA over both 7-day and 21-day periods. The aggregation of the PA to form nanotapes resulted in a notable enhancement in this activity, with an approximately two-fold increase in collagen production per cell. This increase was reduced by the addition of an ALK inhibitor. The data presented reveal a stimulatory effect upon collagen synthesis by the primary cells of the corneal stroma, and demonstrate a direct influence of supra-molecular assembly of the PA upon the cellular response observed. The effects of PA upon fibroblasts were dependent upon ALK receptor function. These findings elucidate the role of self-assembled nanostructures in the biological activity of peptide amphiphiles, and support the potential use of a self-assembling lumican derived PA as a novel biomaterial, intended to promote collagen deposition for wound repair and tissue engineering purposes.

  19. A lactobacillus rhamnosus GG-derived soluble protein, p40, stimulates ligand release from intestinal epithelial cells to transactivate epidermal growth factor receptor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Protein p40, a Lactobacillus rhamnosus GG (LGG)-derived soluble protein, ameliorates intestinal injury and colitis, reduces apoptosis and preserves barrier function by activation of EGF receptor (EGFR) in intestinal epithelial cells. The aim of this study was to determine the mechanisms by which p40...

  20. Subchronic safety evaluation of EPO-018B, a pegylated peptidic erythropoiesis stimulating agent, after 5-week subcutaneous injection in Cynomolgus monkeys and Sprague-Dawley rats.

    PubMed

    Gong, Xue-Lian; Zhang, Xiao-Dong; Li, Juan; Zhang, Xiao-Fang; Zong, Ying; Lu, Guo-Cai; Yuan, Bo-Jun

    2013-10-01

    EPO-018B, a synthetic peptide-based erythropoiesis stimulating agent (ESA), is coupled to polyethylene glycol (PEG) and designed to specifically bind and activate the erythropoietin (EPO) receptor to result in production of red blood cells. This study was designed to evaluate the potential subchronic toxicity of EPO-018B for Cynomolgus monkeys and Sprague-Dawley rats both at 0, 0.5, 5 and 50 mg/kg every week for 5 weeks, followed by 6-week recovery for rats and 12-week recovery for monkeys. The No Observed Adverse Effect Level (NOAEL) for rats and monkeys were both considered to be at least 0.5 mg/kg/day, the minimum toxic dose to be 5.0 mg/kg/day and the severe toxic dose to be more than 50.0 mg/kg/day. The toxicological effects included the exaggerated pharmacology and secondary sequelae that resulted from an erythropoiesis-stimulating agent treatment to healthy animals. Most treatment induced effects were reversible or showed ongoing recovery upon discontinuation of treatment. The anticipated patient population for EPO-018B treatment is targeted to be the anemia patients caused by chronic renal failure or chemotherapy against to cancer and is expected to have an ideal clinical application prospect.

  1. Growth hormone-releasing peptide-biotin conjugate stimulates myocytes differentiation through insulin-like growth factor-1 and collagen type I

    PubMed Central

    Lim, Chae Jin; Jeon, Jung Eun; Jeong, Se Kyoo; Yoon, Seok Jeong; Kwon, Seon Deok; Lim, Jina; Park, Keedon; Kim, Dae Yong; Ahn, Jeong Keun; Kim, Bong-Woo

    2015-01-01

    Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition. [BMB Reports 2015; 48(9): 501-506] PMID:25644636

  2. Growth hormone-releasing peptide-biotin conjugate stimulates myocytes differentiation through insulin-like growth factor-1 and collagen type I.

    PubMed

    Lim, Chae Jin; Jeon, Jung Eun; Jeong, Se Kyoo; Yoon, Seok Jeong; Kwon, Seon Deok; Lim, Jina; Park, Keedon; Kim, Dae Yong; Ahn, Jeong Keun; Kim, Bong-Woo

    2015-09-01

    Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition.

  3. Alpha(1)- and beta-adrenoceptor stimulation differentially activate p38-MAPK and atrial natriuretic peptide production in the perfused amphibian heart.

    PubMed

    Aggeli, Ioanna-Katerina S; Gaitanaki, Catherine; Lazou, Antigone; Beis, Isidoros

    2002-08-01

    We investigated the activation of p38-MAPK by various adrenergic agents in the perfused Rana ridibunda heart. Phenylephrine (50 micromol l(-1)) rapidly induced the differential activation of all three mitogen-activated protein kinase (MAPK) subfamilies (ERK, JNKs and p38-MAPK) in this experimental system. Focusing on p38-MAPK response to phenylephrine, we found that the kinase phosphorylation reached maximal values at 30 s, declining thereafter to basal values at 15 min. p38-MAPK activation by phenylephrine was verified as exclusively alpha(1)-AR-mediated. Furthermore, SB203580 (1 micromol l(-1)) abolished the kinase phosphorylation by phenylephrine. Isoproterenol (50 micromol l(-1)) was also shown to activate p38-MAPK in a time- and temperature-dependent manner. A marked, sustained p38-MAPK activation profile was observed at 25 degrees C, while at 18 degrees C the kinase response to isoproterenol was modest. Isoproterenol effect on p38-MAPK stimulation was beta-AR-mediated. Immunohistochemical studies revealed the enhanced presence of phosphorylated p38-MAPK and atrial natriuretic peptide (ANP) in both phenylephrine- and isoproterenol-stimulated hearts, a reaction completely blocked by the respective specific antagonists, or the specific p38-MAPK inhibitor SB203580. These findings indicate a functional correlation between p38-MAPK activation and ANP accumulation in the perfused amphibian heart.

  4. Differential induction of innate defense antimicrobial peptides in primary nasal epithelial cells upon stimulation with inflammatory cytokines, Th17 cytokines or bacterial conditioned medium from Staphylococcus aureus isolates.

    PubMed

    Burgey, Christine; Kern, Winfried V; Römer, Winfried; Rieg, Siegbert

    2016-01-01

    To date it is incompletely understood why half of the human population is intrinsically resistant to Staphylococcus aureus colonization whereas the other half is intermittently or permanently colonized. Nasal colonization represents the primary niche for S. aureus. We therefore investigated whether primary nasal epithelial cells (HNEC) express antimicrobial peptides (AMPs) upon stimulation by inflammatory cytokines or bacterial conditioned medium (BCM) of different colonizing and invasive staphylococci. Stimulation with classical cytokines (IL-1β, TNF-α, IFN-γ) potently induced hBD-3 and RNase7 in HNEC. Th17 cytokines (IL-17A, IL-17F, IL-22) yielded comparably weak hBD-3 and RNase7 induction and no synergistic effects with classical cytokines. BCM of S. aureus and Staphylococcus epidermidis isolates moderately induced hBD3 and RNase7 mRNA expression without significant differences when comparing colonizing vs. invasive isolates. Our results indicate that HNEC contribute to the innate defense by secretion of an AMP-containing chemical defense shield along the nasal mucosa i.e. within the primary colonization niche of S. aureus. Further studies are needed to investigate whether a deficient AMP expression in the nasal mucosa may be related to different S. aureus carrier states. AMPs or AMP-inducing agents may be promising candidates for future topical decolonization regimens that aim to prevent invasive S. aureus infections.

  5. ER stress stimulates production of the key antimicrobial peptide, cathelicidin, by forming a previously unidentified intracellular S1P signaling complex.

    PubMed

    Park, Kyungho; Ikushiro, Hiroko; Seo, Ho Seong; Shin, Kyong-Oh; Kim, Young Il; Kim, Jong Youl; Lee, Yong-Moon; Yano, Takato; Holleran, Walter M; Elias, Peter; Uchida, Yoshikazu

    2016-03-08

    We recently identified a previously unidentified sphingosine-1-phosphate (S1P) signaling mechanism that stimulates production of a key innate immune element, cathelicidin antimicrobial peptide (CAMP), in mammalian cells exposed to external perturbations, such as UVB irradiation and other oxidative stressors that provoke subapoptotic levels of endoplasmic reticulum (ER) stress, independent of the well-known vitamin D receptor-dependent mechanism. ER stress increases cellular ceramide and one of its distal metabolites, S1P, which activates NF-κB followed by C/EBPα activation, leading to CAMP production, but in a S1P receptor-independent fashion. We now show that S1P activates NF-κB through formation of a previously unidentified signaling complex, consisting of S1P, TRAF2, and RIP1 that further associates with three stress-responsive proteins; i.e., heat shock proteins (GRP94 and HSP90α) and IRE1α. S1P specifically interacts with the N-terminal domain of heat shock proteins. Because this ER stress-initiated mechanism is operative in both epithelial cells and macrophages, it appears to be a universal, highly conserved response, broadly protective against diverse external perturbations that lead to increased ER stress. Finally, these studies further illuminate how ER stress and S1P orchestrate critical stress-specific signals that regulate production of one protective response by stimulating production of the key innate immune element, CAMP.

  6. Noxious mechanical stimulation evokes the segmental release of opioid peptides that induce μ-opioid receptor internalization in the presence of peptidase inhibitors

    PubMed Central

    Lao, Lijun; Song, Bingbing; Chen, Wenling; Marvizón, Juan Carlos G.

    2008-01-01

    The internalization of μ-opioid receptors (MORs) provides an ideal way to locate areas of opioid peptide release. We used this method to study opioid release in the spinal cord evoked by noxious stimuli in anesthetized rats. Previous studies have shown that opioids released in the spinal cord produce MOR internalization only when they are protected from peptidase degradation. Accordingly, rats were implanted with chronic intrathecal catheters that were used to inject a mixture of peptidase inhibitors (amastatin, captopril and phosphoramidon) onto the lumbar spinal cord. Five minutes later, a noxious stimulus was delivered to the paw. Lumbar spinal segments were double-stained with antibodies against MORs and neurokinin 1 receptors (NK1Rs) using immunofluorescence. Mechanical stimulation of the hindpaw consisted of repeated 10 sec clamps with a hemostat for 10 min. In the ipsilateral dorsal horn, the stimulus produced abundant NK1R internalization in segments L3–L6, and a more modest but significant MOR internalization in segments L5 and L6. In the contralateral dorsal horn, NK1R was substantially lower and MOR internalization was negligible. The same mechanical stimulus applied to a forepaw did not produce NK1R or MOR internalization in the lumbar spinal cord. Thermal stimulation consisted of immersing a hindpaw in water at 52 °C for 2 min. It produced substantial NK1R internalization ipsilaterally in segment L6, but no MOR internalization. These results show that mechanical stimulation induces segmental opioid release, i.e., in the dorsal horn receiving the noxious signals and not in other spinal segments. PMID:18207137

  7. Solid-phase peptide head-to-side chain cyclodimerization: discovery of C(2)-symmetric cyclic lactam hybrid α-melanocyte-stimulating hormone (MSH)/agouti-signaling protein (ASIP) analogues with potent activities at the human melanocortin receptors.

    PubMed

    Mayorov, Alexander V; Cai, Minying; Palmer, Erin S; Liu, Zhihua; Cain, James P; Vagner, Josef; Trivedi, Dev; Hruby, Victor J

    2010-10-01

    A novel hybrid melanocortin pharmacophore was designed based on the pharmacophores of the agouti-signaling protein (ASIP), an endogenous melanocortin antagonist, and α-melanocyte-stimulating hormone (α-MSH), an endogenous melanocortin agonist. The designed hybrid ASIP/MSH pharmacophore was explored in monomeric cyclic, and cyclodimeric templates. The monomeric cyclic disulfide series yielded peptides with hMC3R-selective non-competitive binding affinities. The direct on-resin peptide lactam cyclodimerization yielded nanomolar range (25-120 nM) hMC1R-selective full and partial agonists in the cyclodimeric lactam series which demonstrates an improvement over the previous attempts at hybridization of MSH and agouti protein sequences. The secondary structure-oriented pharmacophore hybridization strategy will prove useful in development of unique allosteric and orthosteric melanocortin receptor modulators. This report also illustrates the utility of peptide cyclodimerization for the development of novel GPCR peptide ligands.

  8. Repertoire of gluten peptides active in celiac disease patients: perspectives for translational therapeutic applications.

    PubMed

    Camarca, Alessandra; Del Mastro, Andrea; Gianfrani, Carmen

    2012-06-01

    Celiac disease is a common and lifelong food intolerance, affecting approximately 1% of the population. Because of a mechanism not completely understood, the ingestion of wheat gluten, and of homologue proteins of barley and rye, induces in genetically predisposed individuals pronounced inflammatory reactions mainly at the site of small intestine. Gluten, the triggering factor, is a complex protein mixture highly resistant to the gastrointestinal enzymatic proteolysis, and this results in the presence of large, and potentially immunogenic, peptides at the intestinal mucosa surface. During the last decade, several studies have defined gluten peptides able to stimulate adaptive T cells, of either CD4 or CD8 phenotype, and to activate innate (non T) immune cells. This review examines the complete repertoire of gluten peptides recognized by celiac T cells and discusses the several translational implications that the identification of these epitopes opens.

  9. Effect of the six-mer synthetic peptide (AT1002) fragment of zonula occludens toxin on the intestinal absorption of cyclosporin A.

    PubMed

    Song, Keon-Hyoung; Fasano, Alessio; Eddington, Natalie D

    2008-03-03

    Zonula occludens toxin (Zot) and its biologically active fragment, delta G, have been shown to reversibly open tight junctions (TJ) in endothelial and epithelial cells. Recently, a six-mer synthetic peptide H-FCIGRL-OH (AT1002) was identified and synthesized that retains the Zot permeating effect on intercellular TJ. The objective of this study was to evaluate the biological activity of AT1002 on enhancing the oral administration of cyclosporin A (CsA). The intestinal permeability enhancing effect of AT1002 on the transport of CsA across Caco-2 cell monolayers was examined after the following treatments, i.e., CsA, CsA/protease inhibitors (PI), CsA/PI/benzalkonium chloride (BC), CsA/AT1002, CsA/PI/AT1002, and CsA/PI/BC/AT1002 (CsA 0.5 microCi/ml, PI (bestatin 15 mM and E-64 5mM), BC 0.005 w/v%, and AT1002 5mM, respectively). Apparent permeability coefficients (P app) were calculated for each treatment. In addition, four treatments, i.e., CsA, CsA/PI/BC, CsA/AT1002, and CsA/PI/BC/AT1002 (CsA 120 microCi/kg, PI (bestatin 30 mg/kg and E-64 10mg/kg), BC 0.1 w/v%, and AT1002 doses of 5, 10 or 40 mg/kg, respectively) were prepared and administered intraduodenally to male Sprague-Dawley rats (230-280 g, n=4-5). Blood samples were collected at 0, 20, 60, and 120 min post-dosing and CsA plasma concentrations were determined subsequently using a Beckman Liquid Scintillation Counter. No significant increases in CsA transport were observed in the Caco-2 cell culture experiments following pre-treatment with AT1002 (5mM). Even though, AT1002 appeared to increase the P app of CsA in each treatment (CsA/AT1002, 1.54+/-0.13 x 10(-6)cm/s and CsA/PI/AT1002, 1.76+/-0.05 x 10(-6)cm/s) compared to each control (CsA and CsA/PI), respectively. The plasma concentration of CsA was significantly increased over a range of 1.55-2.50 at 10 and 40 mg/kg dose of AT1002. Also, AUC 0-120 min of CsA over a range of 1.64-2.14 and the Cmax of CsA over a range of 1.77-2.56 was statistically and

  10. Glucagonlike Peptide 2 Analogue Teduglutide

    PubMed Central

    Chaturvedi, Lakshmi S.; Basson, Marc D.

    2015-01-01

    IMPORTANCE Short bowel syndrome occurs when a shortened intestine cannot absorb sufficient nutrients or fluids. Teduglutide is a recombinant analogue of human glucagonlike peptide 2 that reduces dependence on parenteral nutrition in patients with short bowel syndrome by promoting enterocytic proliferation, increasing the absorptive surface area. However, enterocyte function depends not only on the number of cells that are present but also on differentiated features that facilitate nutrient absorption and digestion. OBJECTIVE To test the hypothesis that teduglutide impairs human intestinal epithelial differentiation. DESIGN AND SETTING We investigated the effects of teduglutide in the modulation of proliferation and differentiation in human Caco-2 intestinal epithelial cells at a basic science laboratory. This was an in vitro study using Caco-2 cells, a human-derived intestinal epithelial cell line commonly used to model enterocytic biology. EXPOSURE Cells were exposed to teduglutide or vehicle control. MAINOUTCOMESAND MEASURES We analyzed the cell cycle by bromodeoxyuridine incorporation or propidium iodide staining and flow cytometry and measured cell proliferation by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. We used quantitative reverse transcription–polymerase chain reaction to assay the expression of the enterocytic differentiation markers villin, sucrase-isomaltase, glucose transporter 2 (GLUT2), and dipeptidyl peptidase 4 (DPP-4), as well as that of the putative differentiation signals schlafen 12 (SLFN12) and caudal-related homeobox intestine-specific transcription factor (Cdx2). Villin promoter activity was measured by a luciferase-based assay. RESULTS The MTS assay demonstrated that teduglutide increased cell numbers by a mean (SD) of 10% (2%) over untreated controls at a maximal 500nM (n = 6, P < .05). Teduglutide increased bromodeoxyuridine-positive cells vs untreated controls by a mean (SD

  11. A nutritional supplement containing lactoferrin stimulates the immune system, extends lifespan, and reduces amyloid β peptide toxicity in Caenorhabditis elegans.

    PubMed

    Martorell, Patricia; Llopis, Silvia; Gonzalez, Nuria; Ramón, Daniel; Serrano, Gabriel; Torrens, Ana; Serrano, Juan M; Navarro, Maria; Genovés, Salvador

    2017-03-01

    Lactoferrin is a highly multifunctional glycoprotein involved in many physiological functions, including regulation of iron absorption and immune responses. Moreover, there is increasing evidence for neuroprotective effects of lactoferrin. We used Caenorhabditis elegans as a model to test the protective effects, both on phenotype and transcriptome, of a nutraceutical product based on lactoferrin liposomes. In a dose-dependent manner, the lactoferrin-based product protected against acute oxidative stress and extended lifespan of C. elegans N2. Furthermore, Paralysis of the transgenic C. elegans strain CL4176, caused by Aβ1-42 aggregates, was clearly ameliorated by treatment. Transcriptome analysis in treated nematodes indicated immune system stimulation, together with enhancement of processes involved in the oxidative stress response. The lactoferrin-based product also improved the protein homeostasis processes, cellular adhesion processes, and neurogenesis in the nematode. In summary, the tested product exerts protection against aging and neurodegeneration, modulating processes involved in oxidative stress response, protein homeostasis, synaptic function, and xenobiotic metabolism. This lactoferrin-based product is also able to stimulate the immune system, as well as improving reproductive status and energy metabolism. These findings suggest that oral supplementation with this lactoferrin-based product could improve the immune system and antioxidant capacity. Further studies to understand the molecular mechanisms related with neuronal function would be of interest.

  12. Intestinal Cancer

    MedlinePlus

    ... connects your stomach to your large intestine. Intestinal cancer is rare, but eating a high-fat diet ... increase your risk. Possible signs of small intestine cancer include Abdominal pain Weight loss for no reason ...

  13. Intestinal leiomyoma

    MedlinePlus

    Leiomyoma - intestine ... McLaughlin P, Maher MM. The duodenum and small intestine. In: Adam A, Dixon AK, Gillard JH, Schaefer- ... Roline CE, Reardon RF. Disorders of the small intestine. In: Marx JA, Hockberger RS, Walls RM, et ...

  14. Intestinal obstruction

    MedlinePlus

    Paralytic ileus; Intestinal volvulus; Bowel obstruction; Ileus; Pseudo-obstruction - intestinal; Colonic ileus ... objects that are swallowed and block the intestines) Gallstones (rare) Hernias Impacted stool Intussusception (telescoping of 1 ...

  15. Intestinal Obstruction

    MedlinePlus

    An intestinal obstruction occurs when food or stool cannot move through the intestines. The obstruction can be complete or partial. ... abdomen Inability to pass gas Constipation A complete intestinal obstruction is a medical emergency. It often requires surgery. ...

  16. Release of angiotensin converting enzyme-inhibitor peptides during in vitro gastrointestinal digestion of Parmigiano Reggiano PDO cheese and their absorption through an in vitro model of intestinal epithelium.

    PubMed

    Basiricò, L; Catalani, E; Morera, P; Cattaneo, S; Stuknytė, M; Bernabucci, U; De Noni, I; Nardone, A

    2015-11-01

    The occurrence of 8 bovine casein-derived peptides (VPP, IPP, RYLGY, RYLG, AYFYPEL, AYFYPE, LHLPLP, and HLPLP) reported as angiotensin converting enzyme-inhibitors (ACE-I) was investigated in the 3-kDa ultrafiltered water-soluble extract (WSE) of Parmigiano Reggiano (PR) cheese samples by ultra-performance liquid chromatography coupled to high-resolution mass spectrometry via an electrospray ionization source. Only VPP, IPP, LHLPLP, and HLPLP were revealed in the WSE, and their total amount was in the range of 8.46 to 21.55 mg/kg of cheese. Following in vitro static gastrointestinal digestion, the same ACE-I peptides along with the newly formed AYFYPEL and AYFYPE were found in the 3 kDa WSE of PR digestates. Digestates presented high amounts (1,880-3,053 mg/kg) of LHLPLP, whereas the remaining peptides accounted for 69.24 to 82.82 mg/kg. The half-maximal inhibitory concentration (IC50) values decreased from 7.92 ± 2.08 in undigested cheese to 3.20 ± 1.69 after in vitro gastrointestinal digestion. The 3-kDa WSE of digested cheeses were used to study the transport of the 8 ACE-I peptides across the monolayers of the Caco-2 cell culture grown on a semipermeable membrane of the transwells. After 1h of incubation, 649.20 ± 148.85 mg/kg of LHLPLP remained in the apical compartment, whereas VPP, IPP, AYFYPEL, AYFYPE, and HLPLP accounted in total for less than 36.78 mg/kg. On average, 0.6% of LHLPLP initially present in the digestates added to the apical compartment were transported intact to the basolateral chamber after the same incubation time. Higher transport rate (2.9%) was ascertained for the peptide HLPLP. No other intact ACE-I peptides were revealed in the basolateral compartment. For the first time, these results demonstrated that the ACE-I peptides HLPLP and LHLPLP present in the in vitro digestates of PR cheese are partially absorbed through an in vitro model of human intestinal epithelium.

  17. High-frequency stimulation-induced peptide release synchronizes arcuate kisspeptin neurons and excites GnRH neurons

    PubMed Central

    Qiu, Jian; Nestor, Casey C; Zhang, Chunguang; Padilla, Stephanie L; Palmiter, Richard D

    2016-01-01

    Kisspeptin (Kiss1) and neurokinin B (NKB) neurocircuits are essential for pubertal development and fertility. Kisspeptin neurons in the hypothalamic arcuate nucleus (Kiss1ARH) co-express Kiss1, NKB, dynorphin and glutamate and are postulated to provide an episodic, excitatory drive to gonadotropin-releasing hormone 1 (GnRH) neurons, the synaptic mechanisms of which are unknown. We characterized the cellular basis for synchronized Kiss1ARH neuronal activity using optogenetics, whole-cell electrophysiology, molecular pharmacology and single cell RT-PCR in mice. High-frequency photostimulation of Kiss1ARH neurons evoked local release of excitatory (NKB) and inhibitory (dynorphin) neuropeptides, which were found to synchronize the Kiss1ARH neuronal firing. The light-evoked synchronous activity caused robust excitation of GnRH neurons by a synaptic mechanism that also involved glutamatergic input to preoptic Kiss1 neurons from Kiss1ARH neurons. We propose that Kiss1ARH neurons play a dual role of driving episodic secretion of GnRH through the differential release of peptide and amino acid neurotransmitters to coordinate reproductive function. DOI: http://dx.doi.org/10.7554/eLife.16246.001 PMID:27549338

  18. Expression and effects of metabotropic CRF1 and CRF2 receptors in rat small intestine.

    PubMed

    Porcher, Christophe; Juhem, Aurélie; Peinnequin, André; Sinniger, Valérie; Bonaz, Bruno

    2005-05-01

    Corticotropin-releasing factor (CRF)-like peptides mediate their effects via two receptor subtypes, CRF1 and CRF2; these receptors have functional implication in the motility of the stomach and colon in rats. We evaluated expression and functions of CRF1 and CRF2 receptors in the rat small intestine (i.e., duodenum and ileum). CRF(1-2)-like immunoreactivity (CRF(1-2)-LI) was localized in fibers and neurons of the myenteric and submucosal ganglia. CRF(1-2)-LI was found in nerve fibers of the longitudinal and circular muscle layers, in the mucosa, and in mucosal cells. Quantitative RT-PCR showed a stronger expression of CRF2 than CRF1 in the ileum, whereas CRF1 expression was higher than CRF2 expression in the duodenum. Functional studies showed that CRF-like peptides increased duodenal phasic contractions and reduced ileal contractions. CRF1 antagonists (CP-154,526 and SSR125543Q) blocked CRF-like peptide-induced activation of duodenal motility but did not block CRF-like peptide-induced inhibition of ileal motility. In contrast, a CRF2 inhibitor (astressin2-B) blocked the effects of CRF-like peptides on ileal muscle contractions but did not influence CRF-like peptide-induced activation of duodenal motility. These results demonstrate the presence of CRF(1-2) in the intestine and demonstrate that, in vitro, CRF-like peptides stimulate the contractile activity of the duodenum through CRF1 receptor while inhibiting phasic contractions of the ileum through CRF2 receptor. These results strongly suggest that CRF-like peptides play a major role in the regulatory mechanisms that underlie the neural control of small intestinal motility through CRF receptors.

  19. "Green" synthesized and coated nanaosilver alters the membrance permeability of barrier (intestinal, brain, endothelial) cells and stimulates oxidative stress pathways in neurons.

    EPA Science Inventory

    Nanosilver's (nanoAg) use in medical applications and consumer products is increasing. Because of this, its "green" synthesis and surface modification with beneficial coatings are desirable. Given nanoAg's potential exposure routes (e.g., dermal, intestin...

  20. Characterization of glucagon-like peptide 2 receptor (GLP2R) gene in chickens: functional analysis, tissue distribution, and developmental expression profile of GLP2R in embryonic intestine.

    PubMed

    Mo, C; Zhong, Y; Wang, Y; Yan, Z; Li, J

    2014-07-01

    This study characterized the glucagon-like peptide 2 receptor (GLP2R) gene of chickens because relatively little is known about the underlying mechanism of GLP2 actions in nonmammalian species. With the use of reverse transcription PCR, we first cloned the chicken GLP2R (cGLP2R) from adult intestine, which was predicted to encode a 529-amino acid receptor precursor. With the use of a pGL3-CRE luciferase reporter system, we demonstrated that cGLP2R expressed in Chinese hamster ovary cells could be potently activated by cGLP2 (half maximal effective concentration, 1.06 nM) but not by its structurally related peptides, including the newly identified glucagon-like peptide, indicating that cGLP2R is a functional receptor specific to cGLP2. Reverse transcription PCR assay revealed that cGLP2R mRNA was widely expressed in adult chicken tissues, including pancreas and various parts of the gastrointestinal tract. With the use of quantitative real-time reverse transcription PCR assays, we further investigated the mRNA expression of cGLP2R and its potential downstream mediators, epidermal growth factor receptor (EGFR) ligands (heparin-binding EGF-like growth factor, epiregulin, and amphiregulin), in the distal duodenum of developing embryos. The mRNA expression levels of GLP2R and EGFR ligands (heparin-binding EGF-like growth factor and amphiregulin) were shown to increase (P < 0.05 or 0.01) during the late embryonic stages (E16 and E20), implying a potential coordinated action of GLP2 and EGFR ligands on embryonic intestine development. Taken together, our findings not only establish a molecular basis to explore the physiological roles of GLP2 in birds, but they also provide comparative insights into the roles of GLP2R and its ligand in vertebrates, such as its roles in embryonic intestine development.

  1. Electrogenic, proton-coupled, intestinal dipeptide transport in herbivorous and carnivorous teleosts.

    PubMed

    Thamotharan, M; Gomme, J; Zonno, V; Maffia, M; Storelli, C; Ahearn, G A

    1996-05-01

    In both herbivorous tilapia (Oreochromis mossambicus) and carnivorous rockfish (Sebastes caurinus) intestinal and pyloric cecal brush-border membrane vesicles (BBMV), [14C]glycylsarcosine ([14C]Gly-Sar) uptake was stimulated by a transmembrane proton gradient. A transmembrane K(+)-diffusion potential (inside negative) stimulated [14C]Gly-Sar uptake above that observed with short-circuited vesicles, whereas an inwardly directed Na+ gradient in both fishes had no effect on peptide uptake. In tilapia, [14C]Gly-Sar influx occurred by the combination of 1) a high-affinity, saturable, proton gradient-dependent carrier system [Kt [concentration that equals one-half of maximum influx (Jmax)] = 0.56 +/- 0.08 mM; Jmax = 1,945.0 +/- 174.6 pmol.mg protein-1.10 s-1]; 2) a low-affinity, nonsaturable (within 1-10 mM), proton gradient-dependent carrier system (nonsaturable carrier-mediated transport component = 4,514.0 +/- 28.1 pmol.mg protein-1.10 s-1.mM-1); and 3) a diffusional component accounting for < 10% of total influx within the concentration range tested. Influx (10 s) of 1-10 mM [14C]Gly-Sar in tilapia intestine was significantly (P < 0.01) inhibited by 10 mM diethylpyrocarbonate, a specific inhibitor of proton-coupled peptide transport systems. [14C]Gly-Sar influx into tilapia BBMV showed cis-inhibition and trans-stimulation by Gly-Pro, suggesting that [14C]Gly-Sar and Gly-Pro shared the same mucosal peptide transporter in fish. These observations strongly suggest that intestinal transport of peptides in herbivorous and carnivorous fishes is proton gradient dependent, electrogenic, sodium independent, and qualitatively resembles the peptide transport paradigm proposed for mammals.

  2. Stimulation of natriuretic peptide receptor C attenuates accumulation of reactive oxygen species and nitric oxide synthesis in ammonia-treated astrocytes.

    PubMed

    Skowrońska, Marta; Zielińska, Magdalena; Albrecht, Jan

    2010-11-01

    Oxidative and nitrosative stress contribute to ammonia-induced astrocytic dysfunction in hepatic encephalopathy. Treatment of cultured astrocytes with 5 mmol/L ammonium chloride ('ammonia') increased the production of reactive oxygen species (ROS), including the toxic NADPH oxidase reaction product, •O(2)(-). Atrial natriuretic peptide (ANP), natriuretic peptide C and a selective natriuretic peptide receptor (NPR)-C ligand, cANP((4-23),) each decreased the total ROS content both in control cells and cells treated with ammonia. However, attenuation of •O(2)(-) accumulation by ANP and cANP((4-23),) was observed in ammonia-treated cells only and the effect of cANP((4-23)) was decreased when the NADPH oxidase-regulatory protein G(iα-2) was blocked with a specific anti-G(iα-2) antibody. Although in contrast to ANP, cANP((4-23)) did not elevate the cGMP content in control astrocytes, it decreased cAMP content and reduced the expression of G(iα-2), the NADPH oxidase-regulatory protein. The results show the presence of functional NPR-C in astrocytes, activation of which (i) attenuates basal ROS production, and (ii) prevents excessive accumulation of the toxic ROS species, •O(2)(-) by ammonia. Ammonia, ANP and cANP((4-23)) added separately, each stimulated formation of NO(x) (nitrates + nitrites) which was associated with up-regulation of the activity [cANP((4-23))] or/and expression (ammonia) of the endothelial isoform of nitric oxide synthase. However, the ammonia-induced increase of NO(x) was not augmented by co-addition of ANP, and was reduced to the control level by co-addition of cANP((4-23)) , indicating that activation of NPR-C may also reduce nitrosative stress. Future hepatic encephalopathy therapy might include the use of cANP((4-23)) or other NPR-C agonists to control oxidative/nitrosative stress induced by ammonia.

  3. Intestinal Epithelial Stem/Progenitor Cells Are Controlled by Mucosal Afferent Nerves

    PubMed Central

    Lundgren, Ove; Jodal, Mats; Jansson, Madeleine; Ryberg, Anders T.; Svensson, Lennart

    2011-01-01

    Background The maintenance of the intestinal epithelium is of great importance for the survival of the organism. A possible nervous control of epithelial cell renewal was studied in rats and mice. Methods Mucosal afferent nerves were stimulated by exposing the intestinal mucosa to capsaicin (1.6 mM), which stimulates intestinal external axons. Epithelial cell renewal was investigated in the jejunum by measuring intestinal thymidine kinase (TK) activity, intestinal 3H-thymidine incorporation into DNA, and the number of crypt cells labeled with BrdU. The influence of the external gut innervation was minimized by severing the periarterial nerves. Principal Findings Luminal capsaicin increased all the studied variables, an effect nervously mediated to judge from inhibitory effects on TK activity or 3H-thymidine incorporation into DNA by exposing the mucosa to lidocaine (a local anesthetic) or by giving four different neurotransmitter receptor antagonists i.v. (muscarinic, nicotinic, neurokinin1 (NK1) or calcitonin gene related peptide (CGRP) receptors). After degeneration of the intestinal external nerves capsaicin did not increase TK activity, suggesting the involvement of an axon reflex. Intra-arterial infusion of Substance P (SP) or CGRP increased intestinal TK activity, a response abolished by muscarinic receptor blockade. Immunohistochemistry suggested presence of M3 and M5 muscarinic receptors on the intestinal stem/progenitor cells. We propose that the stem/progenitor cells are controlled by cholinergic nerves, which, in turn, are influenced by mucosal afferent neuron(s) releasing acetylcholine and/or SP and/or CGRP. In mice lacking the capsaicin receptor, thymidine incorporation into DNA and number of crypt cells labeled with BrdU was lower than in wild type animals suggesting that nerves are important also in the absence of luminal capsaicin, a conclusion also supported by the observation that atropine lowered thymidine incorporation into DNA by 60% in control

  4. Single-chain bifunctional vascular endothelial growth factor (VEGF)-follicle-stimulating hormone (FSH)-C-terminal peptide (CTP) is superior to the combination therapy of recombinant VEGF plus FSH-CTP in stimulating angiogenesis during ovarian folliculogenesis.

    PubMed

    Trousdale, Rhonda K; Pollak, Susan V; Klein, Jeffrey; Lobel, Leslie; Funahashi, Yasuhiro; Feirt, Nikki; Lustbader, Joyce W

    2007-03-01

    Infertility technologies often employ exogenous gonadotropin therapy to increase antral follicle production. In an effort to enhance ovarian response, several long-acting FSH therapies have been developed including an FSH-C-terminal peptide (CTP), where the FSH subunits are linked by the CTP moiety from human chorionic gonadotropin, which is responsible for the increased half-life of human chorionic gonadotropin. We found that administration of FSH-CTP for ovarian hyperstimulation in rats blunted ovarian follicle vascular development. In women, reduced ovarian vasculature has been associated with lower pregnancy rates. We were interested in determining whether vascular endothelial growth factor (VEGF) therapy could enhance ovarian angiogenesis in FSH-CTP-treated rats. Coadministration of systemic FSH-CTP plus recombinant VEGF was compared with treatment with a novel, single-chain bifunctional VEGF-FSH-CTP (VFC) analog. For VFC, the FSH portion targets the protein to the ovary and stimulates follicle growth, whereas VEGF enhances local vascular development. Both in vitro and in vivo studies confirm the dual FSH and VEGF action of the VFC protein. Evaluation of ovarian follicle development demonstrates that administration of combination therapy using VEGF and FSH-CTP failed to increase follicle vasculature above levels seen with FSH-CTP monotherapy. However, treatment with VFC significantly increased follicle vascular development while concurrently increasing the number of large antral follicles produced. In conclusion, we report the production and characterization of a long-acting, bifunctional VEGF-FSH-CTP protein that is superior to combination therapy for enhancing VEGF activity in the ovary and stimulating follicular angiogenesis in rats.

  5. Differential gene expression of RAW 264.7 macrophages in response to the RGD peptide lunasin with and without lipopolysaccharide stimulation.

    PubMed

    Dia, Vermont P; de Mejia, Elvira Gonzalez

    2011-10-01

    Lunasin is a novel peptide from soybean with demonstrated chemopreventive property. We compared the effect of lunasin on gene expression of RAW 264.7 macrophages with and without lipopolysaccharide (LPS)-stimulation. Our hypothesis was that lunasin will have a differential effect in RAW 264.7 gene expression in a normal and challenged state. Analysis of the microarray data using False Discovery Rate (FDR) method resulted in the identification of 340 up-regulated and 162 down-regulated genes (FDR p-value <0.05) associated with simultaneous treatment of lunasin and LPS for 24h. Treatment of lunasin with no LPS for 24h resulted in the up-regulation of 855 genes and down-regulation of 397 genes. Pre-treatment of lunasin for 24h resulted in the up-regulation of 35 genes and down-regulation of 65 genes in LPS-stimulated RAW 264.7 macrophages. GeneVenn analysis of these three sets of genes showed that there are 66 genes common among the three groups which are mostly associated with regulation of cell death, ion binding and transcription as datamined by DAVID. Analysis of the 838 genes unique to lunasin alone by functional annotation clustering tool showed that lunasin mostly affected genes associated with RNA processing, apoptosis and protein kinase activity. Further datamining of these genes by ingenuity pathway analysis (IPA) showed that lunasin affected genes involved in cellular growth and proliferation, cellular function and maintenance, and cell to cell signaling and interaction. These findings support the potential chemopreventive and chemotherapeutic use of lunasin against cancer.

  6. A novel system of artificial antigen-presenting cells efficiently stimulates Flu peptide-specific cytotoxic T cells in vitro

    SciTech Connect

    Han, Hui; Peng, Ji-Run; Chen, Peng-Cheng; Gong, Lei; Qiao, Shi-Shi; Wang, Wen-Zhen; Cui, Zhu-Qingqing; Yu, Xin; Wei, Yu-Hua; Leng, Xi-Sheng

    2011-08-05

    Highlights: {yields} Adoptive immunotherapy depends on relevant numbers of cytolytic T lymphocytes. {yields} An ideal artificial APCs system was successfully prepared in vivo. {yields} Controlled release of IL-2 leads to much more T-cell expansion. {yields} This system is better than general cellular APCs on T-cell expansion. -- Abstract: Therapeutic numbers of antigen-specific cytotoxic T lymphocytes (CTLs) are key effectors in successful adoptive immunotherapy. However, efficient and reproducible methods to meet the qualification remain poor. To address this issue, we designed the artificial antigen-presenting cell (aAPC) system based on poly(lactic-co-glycolic acid) (PLGA). A modified emulsion method was used for the preparation of PLGA particles encapsulating interleukin-2 (IL-2). Biotinylated molecular ligands for recognition and co-stimulation of T cells were attached to the particle surface through the binding of avidin-biotin. These formed the aAPC system. The function of aAPCs in the proliferation of specific CTLs against human Flu antigen was detected by enzyme-linked immunospot assay (ELISPOT) and MTT staining methods. Finally, we successfully prepared this suitable aAPC system. The results show that IL-2 is released from aAPCs in a sustained manner over 30 days. This dramatically improves the stimulatory capacity of this system as compared to the effect of exogenous addition of cytokine. In addition, our aAPCs promote the proliferation of Flu antigen-specific CTLs more effectively than the autologous cellular APCs. Here, this aAPC platform is proved to be suitable for expansion of human antigen-specific T cells.

  7. Fasting and nutrient-stimulated plasma peptide-YY levels are elevated in critical illness and associated with feed intolerance: an observational, controlled study

    PubMed Central

    Nguyen, Nam Q; Fraser, Robert JL; Chapman, Marianne; Bryant, Laura K; Wishart, Judith; Holloway, Richard H; Horowitz, Michael

    2006-01-01

    Introduction Delayed gastric emptying and feed intolerance occur frequently in the critically ill. In these patients, gastric motor responses to nutrients are disturbed. Peptide YY (PYY) slows gastric emptying. The aim of this study was to determine fasting and nutrient-stimulated plasma PYY concentrations and their relationship to cholecystokinin (CCK) in critically ill patients. Methods Studies were performed in 19 unselected mechanically ventilated critically ill patients (12 males; 48 ± 7 years old) in a randomised, single-blind fashion. Subjects received a 60-minute duodenal infusion of Ensure® at either 1 or 2 kcal/minute. Blood samples were collected at baseline and at 20, 40, 60, and 180 minutes following commencement of the nutrient infusion for the measurement of plasma PYY and CCK concentrations (using radioimmunoassay). Patient data were compared to 24 healthy subjects (17 males; 43 ± 2 years old). Results Fasting PYY concentration was higher in patients (P < 0.05), particularly in those with feed intolerance (P < 0.05). Plasma PYY concentrations were higher in patients during nutrient infusion (area under the curve [AUC] at 1 kcal/minute: 2,265 ± 718 versus 1,125 ± 138 pmol/l.min, P < 0.05; at 2 kcal/minute: 2,276 ± 303 versus 1,378 ± 210 pmol/l.min, P = 0.01) compared to healthy subjects. The magnitude of PYY elevation was greater in patients during the 1 kcal/minute infusion (AUC: 441 ± 153 versus 186 ± 58 pmol/l.min, P < 0.05), but not the 2 kcal/minute infusion. Fasting and nutrient-stimulated plasma CCK concentrations were higher in patients (P < 0.05). There was a relationship between plasma PYY and CCK concentrations during fasting (r = 0.52, P < 0.05) and nutrient infusion (r = 0.98, P < 0.0001). Conclusion In critical illness, both fasting and nutrient-stimulated plasma PYY concentrations are elevated, particularly in patients with feed intolerance, in conjunction with increased CCK concentrations. PMID:17173662

  8. TLR5 mediates CD172α(+) intestinal lamina propria dendritic cell induction of Th17 cells.

    PubMed

    Liu, Han; Chen, Feidi; Wu, Wei; Cao, Anthony T; Xue, Xiaochang; Yao, Suxia; Evans-Marin, Heather L; Li, Yan-Qing; Cong, Yingzi

    2016-02-24

    Multiple mechanisms exist in regulation of host responses to massive challenges from microbiota to maintain immune homeostasis in the intestines. Among these is the enriched Th17 cells in the intestines, which regulates intestinal homeostasis through induction of antimicrobial peptides and secretory IgA among others. However, the means by which Th17 cells develop in response to microbiota is still not completely understood. Although both TLR5 and CD172α(+) lamina propria dendritic cells (LPDC) have been shown to promote Th17 cell development, it is still unclear whether TLR5 mediates the CD172α(+)LPDC induction of Th17 cells. By using a microbiota antigen-specific T cell reporter mouse system, we demonstrated that microbiota antigen-specific T cells developed into Th17 cells in the intestinal LP, but not in the spleen when transferred into TCRβxδ(-/-) mice. LPDCs expressed high levels of TLR5, and most CD172α(+)LPDCs also co-expressed TLR5. LPDCs produced high levels of IL-23, IL-6 and TGFβ when stimulated with commensal flagellin and promoted Th17 cell development when cultured with full-length CBir1 flagellin but not CBir1 peptide. Wild-type CD172α(+), but not CD172α(-), LPDCs induced Th17 cells, whereas TLR5-deficient LPDC did not induce Th17 cells. Our data thereby demonstrated that TLR5 mediates CD172α(+)LPDC induction of Th17 cells in the intestines.

  9. Gut hormone release after intestinal resection.

    PubMed Central

    Besterman, H S; Adrian, T E; Mallinson, C N; Christofides, N D; Sarson, D L; Pera, A; Lombardo, L; Modigliani, R; Bloom, S R

    1982-01-01

    To investigate the possible role of gut and pancreatic hormones in the adaptive responses to gut resection, plasma concentrations of the circulating hormones were measured, in response to a test breakfast, in patients with either small or large intestinal resection and in healthy control subjects. In 18 patients with partial ileal resection a significant threefold rise was found in basal and postprandial levels of pancreatic polypeptide, a fourfold increase in motilin, and more than a twofold increase in gastrin and enteroglucagon levels compared with healthy controls. In contrast, nine patients with colonic resection had a threefold rise in levels of pancreatic polypeptide only. One or more of these peptides may have a role in stimulating the adaptive changes found after gut resection. PMID:7117905

  10. Isolation and characterization of a resistant core peptide of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF); confirmation of the GM-CSF amino acid sequence by mass spectrometry.

    PubMed Central

    Tsarbopoulos, A.; Pramanik, B. N.; Labdon, J. E.; Reichert, P.; Gitlin, G.; Patel, S.; Sardana, V.; Nagabhushan, T. L.; Trotta, P. P.

    1993-01-01

    A trypsin-resistant core peptide of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) was isolated and analyzed by high-energy Cs+ liquid secondary-ion (LSI) mass spectrometric analysis. This analysis provided successful detection of the high-mass disulfide-linked core peptide as well as information confirming the existence of disulfide pairing. Similarly, LSI mass spectrometric analysis of the peptide fragments isolated chromatographically from a Staphylococcus aureus V8 protease digest of rhGM-CSF provided rapid confirmation of the cDNA-derived sequence and determination of the existing disulfide bonds between cysteine residues 54-96 and 88-121. Electrospray ionization mass spectrometry was employed to measure the molecular weight of the intact protein and to determine the number of the disulfide bonds in the protein molecule by comparative analysis of the protein before and after reduction with beta-mercaptoethanol. PMID:8268804

  11. BT cationic peptides: small peptides that modulate innate immune responses of chicken heterophils and monocytes.

    PubMed

    Kogut, Michael H; Genovese, Kenneth J; He, Haiqi; Swaggerty, Christina L; Jiang, Yi Wei

    2012-01-15

    Neonatal poultry exhibit a transient susceptibility to infectious diseases during the first week of life that stems from inefficient host defense mechanisms. Yet, the initial host immune response to pathogens is a critical determinant of disease resistance and susceptibility. With this context in mind, novel ways to stimulate or modulate the hosts' natural immune response is emerging as an important area of interest for food animal producers including the poultry industry. Specifically, we have been investigating new modulation strategies tailored around the selective stimulation of the host's immune system, and particularly rapid acting innate immunity, as an alternative to direct targeting of microbial pathogens. One such approach that we have been investigating is the use of a group of cationic peptides produced by a Gram-positive soil bacterium, Brevibacillus texasporus (BT peptides). We have previously shown that, provided as a feed additive, BT peptides significantly induced a concentration-dependent protection against cecal colonization and extraintestinal colonization by Salmonella enterica serovar Enteritidis (SE). This protection is not the result of direct antibacterial activity of the BT peptides on the SE since the concentrations used were below the minimum inhibitory concentration for SE. We also found that BT are not absorbed in the intestine, but still induce a significant up-regulation in the functional efficiency of peripheral blood heterophils and monocytes. The mechanisms of this immune modulation are unknown. Here, using in vitro models for measuring: (1) leukocyte oxidative burst, (2) changes in leukocyte cytokine and chemokines gene expression profiles, and (3) phosphorylation of the mitogen activated protein kinases (MAPKs) in leukocytes, we evaluated the role of BT peptides as priming mediators for heterophil and monocyte responses at the level of cell function, gene transcription/expression, and cell phosphorylation following stimulation

  12. Multiple Factors Related to the Secretion of Glucagon-Like Peptide-1

    PubMed Central

    Wang, XingChun; Liu, Huan; Chen, Jiaqi; Li, Yan; Qu, Shen

    2015-01-01

    The glucagon-like peptide-1 is secreted by intestinal L cells in response to nutrient ingestion. It regulates the secretion and sensitivity of insulin while suppressing glucagon secretion and decreasing postprandial glucose levels. It also improves beta-cell proliferation and prevents beta-cell apoptosis induced by cytotoxic agents. Additionally, glucagon-like peptide-1 delays gastric emptying and suppresses appetite. The impaired secretion of glucagon-like peptide-1 has negative influence on diabetes, hyperlipidemia, and insulin resistance related diseases. Thus, glucagon-like peptide-1-based therapies (glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors) are now well accepted in the management of type 2 diabetes. The levels of glucagon-like peptide-1 are influenced by multiple factors including a variety of nutrients. The component of a meal acts as potent stimulants of glucagon-like peptide-1 secretion. The levels of its secretion change with the intake of different nutrients. Some drugs also have influence on GLP-1 secretion. Bariatric surgery may improve metabolism through the action on GLP-1 levels. In recent years, there has been a great interest in developing effective methods to regulate glucagon-like peptide-1 secretion. This review summarizes the literature on glucagon-like peptide-1 and related factors affecting its levels. PMID:26366173

  13. Opioid receptors on guinea-pig intestinal crypt epithelial cells.

    PubMed Central

    Lang, M E; Davison, J S; Bates, S L; Meddings, J B

    1996-01-01

    1. Opioid peptides promote net intestinal absorption via two mechanisms: stimulation of Na+ and Cl- absorption and inhibition of Cl- secretion. Although these transport changes are predominantly mediated by submucosal neurones, it is currently unclear whether opioid peptides can regulate enterocyte function directly. We therefore tested the hypothesis that enterocytes have specific opioid receptors. 2. Villus and crypt jejunal epithelial cells were isolated by the distended sac method from anaesthetized guinea-pigs. Flow cytometry was used to resolve enterocytes from other cell types and to determine whether binding of a fluorescently labelled opioid antagonist, naltrexone-FITC, could be prevented by unlabelled mu- and delta-opioid receptor agonists. A population of crypt enterocytes (approximately 21%) exhibited high-affinity naltrexone-FITC binding to both mu- and delta-type binding sites that was stereoselective and sodium dependent. Villus enterocytes did not exhibit any of these characteristics. 3. Basal cAMP production was elevated in both villus and crypt cells treated with IBMX (3-isobutyl-1-methylxanthine). Villus cells did not respond to 100 nM vasoactive intestinal peptide (VIP), nor were they affected by opioid peptides. In contrast, 100 nM VIP significantly increased cAMP production in crypt epithelial cells, which was significantly reduced by both morphiceptin and D-Ser2-Leu-Enk-Thr. This opioid-mediated effect was stereoselective and blocked by the opioid receptor antagonist naltrexone. 4. These experiments suggest that enterocytes isolated from the crypt epithelium of guineapigs have both mu- and delta-types of opioid receptors. It is possible that these cells participate in opioid-mediated regulation of intestinal secretion. Images Figure 12 PMID:8951719

  14. Evaluation of new Tc-99m-labeled Arg-X-Asp-conjugated α-melanocyte stimulating hormone peptides for melanoma imaging.

    PubMed

    Flook, Adam M; Yang, Jianquan; Miao, Yubin

    2013-09-03

    The purpose of this study was to examine the melanoma targeting and imaging properties of two new (99m)Tc-labeled Arg-X-Asp-conjugated α-melanocyte stimulating hormone (α-MSH) peptides. RTD-Lys-(Arg(11))CCMSH {c[Asp-Arg-Thr-Asp-DTyr]-Lys-Cys-Cys-Glu-His-DPhe-Arg-Trp-Cys-Arg-Pro-Val-NH2} and RVD-Lys-(Arg(11))CCMSH peptides were synthesized, and their melanocortin-1 (MC1) receptor binding affinities were determined in B16/F1 melanoma cells. The biodistribution and melanoma imaging properties of (99m)Tc-RTD-Lys-(Arg(11))CCMSH and (99m)Tc-RVD-Lys-(Arg(11))CCMSH were determined in B16/F1 melanoma-bearing C57 mice. The IC50 values of RTD-Lys-(Arg(11))CCMSH and RVD-Lys-(Arg(11))CCMSH were 0.7 ± 0.07 and 1.0 ± 0.3 nM in B16/F1 melanoma cells. Both (99m)Tc-RTD-Lys-(Arg(11))CCMSH and (99m)Tc-RVD-Lys-(Arg(11))CCMSH displayed high melanoma uptake. (99m)Tc-RTD-Lys-(Arg(11))CCMSH exhibited the highest tumor uptake of 18.77 ± 5.13% ID/g at 2 h postinjection, whereas (99m)Tc-RVD-Lys-(Arg(11))CCMSH reached the highest tumor uptake of 19.63 ± 4.68% ID/g at 4 h postinjection. Both (99m)Tc-RTD-Lys-(Arg(11))CCMSH and (99m)Tc-RVD-Lys-(Arg(11))CCMSH showed low accumulation in normal organs (<1.7% ID/g) except for the kidneys at 2 h postinjection. The renal uptake of (99m)Tc-RTD-Lys-(Arg(11))CCMSH and (99m)Tc-RVD-Lys-(Arg(11))CCMSH was 135.14 ± 23.62 and 94.01 ± 18.31% ID/g at 2 h postinjection, respectively. The melanoma lesions were clearly visualized by single-photon emission computed tomography (SPECT)/CT using either (99m)Tc-RTD-Lys-(Arg(11))CCMSH or (99m)Tc-RVD-Lys-(Arg(11))CCMSH as an imaging probe at 2 h postinjection. Overall, the introduction of Thr or Val residue retained high melanoma uptake of (99m)Tc-RTD-Lys-(Arg(11))CCMSH and (99m)Tc-RVD-Lys-(Arg(11))CCMSH. However, high renal uptake of (99m)Tc-RTD-Lys-(Arg(11))CCMSH and (99m)Tc-RVD-Lys-(Arg(11))CCMSH need to be reduced to facilitate their future applications.

  15. Bacteriocin Inducer Peptides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Novel peptides produced by bacteriocin-producing bacteria stimulate the production of bacteriocins in vitro. The producer bacteria are cultured in the presence of a novel inducer bacteria and a peptide having a carboxy terminal sequence of VKGLT in order to achieve an increase in bacteriocin produc...

  16. Saturated fat stimulates obesity and hepatic steatosis and affects gut microbiota composition by an enhanced overflow of dietary fat to the distal intestine.

    PubMed

    de Wit, Nicole; Derrien, Muriel; Bosch-Vermeulen, Hanneke; Oosterink, Els; Keshtkar, Shohreh; Duval, Caroline; de Vogel-van den Bosch, Johan; Kleerebezem, Michiel; Müller, Michael; van der Meer, Roelof

    2012-09-01

    We studied the effect of dietary fat type, varying in polyunsaturated-to-saturated fatty acid ratios (P/S), on development of metabolic syndrome. C57Bl/6J mice were fed purified high-fat diets (45E% fat) containing palm oil (HF-PO; P/S 0.4), olive oil (HF-OO; P/S 1.1), or safflower oil (HF-SO; P/S 7.8) for 8 wk. A low-fat palm oil diet (LF-PO; 10E% fat) was used as a reference. Additionally, we analyzed diet-induced changes in gut microbiota composition and mucosal gene expression. The HF-PO diet induced a higher body weight gain and liver triglyceride content compared with the HF-OO, HF-SO, or LF-PO diet. In the intestine, the HF-PO diet reduced microbial diversity and increased the Firmicutes-to-Bacteroidetes ratio. Although this fits a typical obesity profile, our data clearly indicate that an overflow of the HF-PO diet to the distal intestine, rather than obesity itself, is the main trigger for these gut microbiota changes. A HF-PO diet-induced elevation of lipid metabolism-related genes in the distal small intestine confirmed the overflow of palm oil to the distal intestine. Some of these lipid metabolism-related genes were previously already associated with the metabolic syndrome. In conclusion, our data indicate that saturated fat (HF-PO) has a more stimulatory effect on weight gain and hepatic lipid accumulation than unsaturated fat (HF-OO and HF-SO). The overflow of fat to the distal intestine on the HF-PO diet induced changes in gut microbiota composition and mucosal gene expression. We speculate that both are directly or indirectly contributive to the saturated fat-induced development of obesity and hepatic steatosis.

  17. The orphan G protein-coupled receptor GPR139 is activated by the peptides: Adrenocorticotropic hormone (ACTH), α-, and β-melanocyte stimulating hormone (α-MSH, and β-MSH), and the conserved core motif HFRW.

    PubMed

    Nøhr, Anne Cathrine; Shehata, Mohamed A; Hauser, Alexander S; Isberg, Vignir; Mokrosinski, Jacek; Andersen, Kirsten B; Farooqi, I Sadaf; Pedersen, Daniel Sejer; Gloriam, David E; Bräuner-Osborne, Hans

    2017-01-01

    GPR139 is an orphan G protein-coupled receptor that is expressed primarily in the brain. Not much is known regarding the function of GPR139. Recently we have shown that GPR139 is activated by the amino acids l-tryptophan and l-phenylalanine (EC50 values of 220 μM and 320 μM, respectively), as well as di-peptides comprised of aromatic amino acids. This led us to hypothesize that GPR139 may be activated by peptides. Sequence alignment of the binding cavities of all class A GPCRs, revealed that the binding pocket of the melanocortin 4 receptor is similar to that of GPR139. Based on the chemogenomics principle "similar targets bind similar ligands", we tested three known endogenous melanocortin 4 receptor agonists; adrenocorticotropic hormone (ACTH) and α- and β-melanocyte stimulating hormone (α-MSH and β-MSH) on CHO-k1 cells stably expressing the human GPR139 in a Fluo-4 Ca(2+)-assay. All three peptides, as well as their conserved core motif HFRW, were found to activate GPR139 in the low micromolar range. Moreover, we found that peptides consisting of nine or ten N-terminal residues of α-MSH activate GPR139 in the submicromolar range. α-MSH1-9 was found to correspond to the product of a predicted cleavage site in the pre-pro-protein pro-opiomelanocortin (POMC). Our results demonstrate that GPR139 is a peptide receptor, activated by ACTH, α-MSH, β-MSH, the conserved core motif HFRW as well as a potential endogenous peptide α-MSH1-9. Further studies are needed to determine the functional relevance of GPR139 mediated signaling by these peptides.

  18. Impact of peptide transporter 1 on the intestinal absorption and pharmacokinetics of valacyclovir after oral dose escalation in wild-type and PepT1 knockout mice.

    PubMed

    Yang, Bei; Hu, Yongjun; Smith, David E

    2013-10-01

    The primary objective of this study was to determine the in vivo absorption properties of valacyclovir, including the potential for saturable proton-coupled oligopeptide transporter 1 (PepT1)-mediated intestinal uptake, after escalating oral doses of prodrug within the clinical dose range. A secondary aim was to characterize the role of PepT1 on the tissue distribution of its active metabolite, acyclovir. [³H]Valacyclovir was administered to wild-type (WT) and PepT1 knockout (KO) mice by oral gavage at doses of 10, 25, 50, and 100 nmol/g. Serial blood samples were collected over 180 minutes, and tissue distribution studies were performed 20 minutes after a 25-nmol/g oral dose of valacyclovir. We found that the C(max) and area under the curve (AUC)₀₋₁₈₀ of acyclovir were 4- to 6-fold and 2- to 3-fold lower, respectively, in KO mice for all four oral doses of valacyclovir. The time to peak concentration of acyclovir was 3- to 10-fold longer in KO compared with WT mice. There was dose proportionality in the C(max) and AUC₀₋₁₈₀ of acyclovir in WT and KO mice over the valacyclovir oral dose range of 10-100 nmol/g (i.e., linear absorption kinetics). No differences were observed in the peripheral tissue distribution of acyclovir once these tissues were adjusted for differences in perfusing drug concentrations in the systemic circulation. In contrast, some differences were observed between genotypes in the concentrations of acyclovir in the distal intestine. Collectively, the findings demonstrate a critical role of intestinal PepT1 in improving the rate and extent of oral absorption for valacyclovir. Moreover, this study provides definitive evidence for the rational development of a PepT1-targeted prodrug strategy.

  19. Intestinal Obstruction

    MedlinePlus

    ... Wall Hernias Inguinal Hernia Acute Mesenteric Ischemia Appendicitis Ileus Intestinal Obstruction Ischemic Colitis Perforation of the Digestive ... Wall Hernias Inguinal Hernia Acute Mesenteric Ischemia Appendicitis Ileus Intestinal Obstruction Ischemic Colitis Perforation of the Digestive ...

  20. The human milk oligosaccharide 2′-fucosyllactose augments the adaptive response to extensive intestinal

    PubMed Central

    Hawkins, Jennifer A.; Ollberding, Nicholas J.; Karns, Rebekah; Morrow, Ardythe L.; Helmrath, Michael A.

    2015-01-01

    Intestinal resection resulting in short bowel syndrome (SBS) carries a heavy burden of long-term morbidity, mortality, and cost of care, which can be attenuated with strategies that improve intestinal adaptation. SBS infants fed human milk, compared with formula, have more rapid intestinal adaptation. We tested the hypothesis that the major noncaloric human milk oligosaccharide 2′-fucosyllactose (2′-FL) contributes to the adaptive response after intestinal resection. Using a previously described murine model of intestinal adaptation, we demonstrated increased weight gain from 21 to 56 days (P < 0.001) and crypt depth at 56 days (P < 0.0095) with 2′-FL supplementation after ileocecal resection. Furthermore, 2′-FL increased small bowel luminal content microbial alpha diversity following resection (P < 0.005) and stimulated a bloom in organisms of the genus Parabacteroides (log2-fold = 4.1, P = 0.035). Finally, transcriptional analysis of the intestine revealed enriched ontologies and pathways related to antimicrobial peptides, metabolism, and energy processing. We conclude that 2′-FL supplementation following ileocecal resection increases weight gain, energy availability through microbial community modulation, and histological changes consistent with improved adaptation. PMID:26702137

  1. Methadone but not morphine inhibits lubiprostone-stimulated Cl- currents in T84 intestinal cells and recombinant human ClC-2, but not CFTR Cl- currents.

    PubMed

    Cuppoletti, John; Chakrabarti, Jayati; Tewari, Kirti; Malinowska, Danuta H

    2013-05-01

    In clinical trials, methadone, but not morphine, appeared to prevent beneficial effects of lubiprostone, a ClC-2 Cl(-) channel activator, on opioid-induced constipation. Effects of methadone and morphine on lubiprostone-stimulated Cl(-) currents were measured by short circuit current (Isc) across T84 cells. Whole cell patch clamp of human ClC-2 (hClC-2) stably expressed in HEK293 cells and in a high expression cell line (HEK293EBNA) as well as human CFTR (hCFTR) stably expressed in HEK293 cells was used to study methadone and morphine effects on recombinant hClC-2 and hCFTR Cl(-) currents. Methadone but not morphine inhibited lubiprostone-stimulated Isc in T84 cells with half-maximal inhibition at 100 nM. Naloxone did not affect lubiprostone stimulation or methadone inhibition of Isc. Lubiprostone-stimulated Cl(-) currents in hClC-2/HEK293 cells, but not forskolin/IBMX-stimulated Cl(-) currents in hCFTR/HEK293 cells, were inhibited by methadone, but not morphine. HEK293EBNA cells expressing hClC-2 showed time-dependent, voltage-activated, CdCl2-inhibited Cl(-) currents in the absence (control) and the presence of lubiprostone. Methadone, but not morphine, inhibited control and lubiprostone-stimulated hClC-2 Cl(-) currents with half-maximal inhibition at 100 and 200-230 nM, respectively. Forskolin/IBMX-stimulated hClC-2 Cl(-) currents were also inhibited by methadone. Myristoylated protein kinase inhibitor (a specific PKA inhibitor) inhibited forskolin/IBMX- but not lubiprostone-stimulated hClC-2 Cl(-) currents. Methadone caused greater inhibition of lubiprostone-stimulated currents added before patching (66.1 %) compared with after patching (28.7 %). Methadone caused inhibition of lubiprostone-stimulated Cl(-) currents in T84 cells and control; lubiprostone- and forskolin/IBMX-stimulated recombinant hClC-2 Cl(-) currents may be the basis for reduced efficacy of lubiprostone in methadone-treated patients.

  2. ECL-cell histamine mobilization in conscious rats: effects of locally applied regulatory peptides, candidate neurotransmitters and inflammatory mediators.

    PubMed

    Norlén, P; Bernsand, M; Konagaya, T; Håkanson, R

    2001-12-01

    1. The ECL cells control gastric acid secretion by mobilizing histamine in response to circulating gastrin. In addition, the ECL cells are thought to operate under nervous control and to be influenced by local inflammatory processes. 2. The purpose of the present study was to monitor histamine mobilization from ECL cells in conscious rats in response to locally applied regulatory peptides, candidate neurotransmitters and inflammatory mediators. 3. Microdialysis probes were implanted in the submucosa of the acid-producing part of the rat stomach. Three days later, the agents to be tested were administered via the microdialysis probe and their effects on basal (48 h fast) and stimulated (intravenous infusion of gastrin-17, 3 nmol kg(-1) h(-1)) mobilization of ECL-cell histamine was monitored by continuous measurement of histamine in the perfusate (radioimmunoassay). 4. Locally administered gastrin-17 and sulfated cholecystokinin-8 mobilized histamine as did pituitary adenylate cyclase-activating peptide-27, vasoactive intestinal peptide, peptide YY, met-enkephalin, endothelin and noradrenaline, adrenaline and isoprenaline. 5. While gastrin, sulfated-cholecystokinin-8, met-enkephalin and isoprenaline induced a sustained elevation of the submucosal histamine concentration, endothelin, peptide YY, pituitary adenylate cyclase activating peptide, vasoactive intestinal peptide, noradrenaline and adrenaline induced a transient elevation. 6. Calcitonin gene-related peptide, galanin, somatostatin and the prostanoid misoprostol inhibited gastrin-stimulated histamine mobilization. 7. The gut hormones neurotensin and secretin and the neuropeptides gastrin-releasing peptide, neuropeptide Y and substance P failed to affect ECL-cell histamine mobilization, while motilin and neuromedin U-25 had weak stimulatory effects. Also acetylcholine, carbachol, serotonin and the amino acid neurotransmitters aspartate, gamma-aminobutyric acid, glutamate and glycine were inactive or weakly

  3. Intestinal hormones and regulation of satiety: the case for CCK, GLP-1, PYY, and Apo A-IV.

    PubMed

    D'Alessio, David

    2008-01-01

    Satiety, the physiologic processes that combine to bring about the cessation of a meal, is controlled in part by intestinal peptide secretion. The effects of cholecystokinin, glucagon-like peptide I, peptide YY, and apolipoprotein A-IV are described.

  4. A rhesus monkey model to characterize the role of gastrin-releasing peptide (GRP) in lung development. Evidence for stimulation of airway growth.

    PubMed Central

    Li, K; Nagalla, S R; Spindel, E R

    1994-01-01

    Gastrin-releasing peptide (GRP) is developmentally expressed in human fetal lung and is a growth factor for normal and neoplastic lung but its role in normal lung development has yet to be clearly defined. In this study we have characterized the expression of GRP and its receptor in fetal rhesus monkey lung and determined the effects of bombesin on fetal lung development in vitro. By RNA blot analysis, GRP mRNA was first detectable in fetal monkey lung at 63 days gestation, reached highest levels at 80 days gestation, and then declined to near adult levels by 120 days gestation; a pattern closely paralleling GRP expression in human fetal lung. As in human lung, in situ hybridization localized GRP mRNA to neuroendocrine cells though during the canalicular phase of development (between 63-80 days gestation) GRP mRNA was present not only in classic pulmonary neuroendocrine cells, but also in cells of budding airways. Immunohistochemistry showed that bombesin-like immunoreactivity was present in neuroendocrine cells, but not in budding airways, suggesting that in budding airways either the GRP mRNA is not translated, is rapidly secreted, or a related, but different RNA is present. RNase protection analysis using a probe to the monkey GRP receptor demonstrated that the time course of receptor RNA expression closely paralleled the time course of GRP RNA expression. In situ hybridization showed that GRP receptors were primarily expressed in epithelial cells of the developing airways. Thus GRP would appear to be secreted from neuroendocrine cells to act on target cells in developing airways. This hypothesis was confirmed by organ culture of fetal monkey lung in the presence of bombesin and bombesin antagonists. Bombesin treatment at 1 and 10 nM significantly increased DNA synthesis in airway epithelial cells and significantly increased the number and size of airways in cultured fetal lung. In fact, culturing 60 d fetal lung for 5 d with 10 nM bombesin increased airway size

  5. Excitotoxicity in the Lung: N-Methyl-D-Aspartate-Induced, Nitric Oxide-Dependent, Pulmonary Edema is Attenuated by Vasoactive Intestinal Peptide and by Inhibitors of Poly(ADP-Ribose) Polymerase

    NASA Astrophysics Data System (ADS)

    Said, Sami I.; Berisha, Hasan I.; Pakbaz, Hedayatollah

    1996-05-01

    Excitatory amino acid toxicity, resulting from overactivation of N-methyl-D-aspartate (NMDA) glutamate receptors, is a major mechanism of neuronal cell death in acute and chronic neurological diseases. We have investigated whether excitotoxicity may occur in peripheral organs, causing tissue injury, and report that NMDA receptor activation in perfused, ventilated rat lungs triggered acute injury, marked by increased pressures needed to ventilate and perfuse the lung, and by high-permeability edema. The injury was prevented by competitive NMDA receptor antagonists or by channel-blocker MK-801, and was reduced in the presence of Mg2+. As with NMDA toxicity to central neurons, the lung injury was nitric oxide (NO) dependent: it required L-arginine, was associated with increased production of NO, and was attenuated by either of two NO synthase inhibitors. The neuropeptide vasoactive intestinal peptide and inhibitors of poly(ADP-ribose) polymerase also prevented this injury, but without inhibiting NO synthesis, both acting by inhibiting a toxic action of NO that is critical to tissue injury. The findings indicate that: (i) NMDA receptors exist in the lung (and probably elsewhere outside the central nervous system), (ii) excessive activation of these receptors may provoke acute edematous lung injury as seen in the ``adult respiratory distress syndrome,'' and (iii) this injury can be modulated by blockade of one of three critical steps: NMDA receptor binding, inhibition of NO synthesis, or activation of poly(ADP-ribose) polymerase.

  6. The gastrin-releasing peptide analog bombesin preserves exocrine and endocrine pancreas morphology and function during parenteral nutrition

    PubMed Central

    Pierre, Joseph F.; Neuman, Joshua C.; Brill, Allison L.; Brar, Harpreet K.; Thompson, Mary F.; Cadena, Mark T.; Connors, Kelsey M.; Busch, Rebecca A.; Heneghan, Aaron F.; Cham, Candace M.; Jones, Elaina K.; Kibbe, Carly R.; Davis, Dawn B.; Groblewski, Guy E.; Kudsk, Kenneth A.

    2015-01-01

    Stimulation of digestive organs by enteric peptides is lost during total parental nutrition (PN). Here we examine the role of the enteric peptide bombesin (BBS) in stimulation of the exocrine and endocrine pancreas during PN. BBS protects against exocrine pancreas atrophy and dysfunction caused by PN. BBS also augments circulating insulin levels, suggesting an endocrine pancreas phenotype. While no significant changes in gross endocrine pancreas morphology were observed, pancreatic islets isolated from BBS-treated PN mice showed a significantly enhanced insulin secretion response to the glucagon-like peptide-1 (GLP-1) agonist exendin-4, correlating with enhanced GLP-1 receptor expression. BBS itself had no effect on islet function, as reflected in low expression of BBS receptors in islet samples. Intestinal BBS receptor expression was enhanced in PN with BBS, and circulating active GLP-1 levels were significantly enhanced in BBS-treated PN mice. We hypothesized that BBS preserved islet function indirectly, through the enteroendocrine cell-pancreas axis. We confirmed the ability of BBS to directly stimulate intestinal enteroid cells to express the GLP-1 precursor preproglucagon. In conclusion, BBS preserves the exocrine and endocrine pancreas functions during PN; however, the endocrine stimulation is likely indirect, through the enteroendocrine cell-pancreas axis. PMID:26185331

  7. The gastrin-releasing peptide analog bombesin preserves exocrine and endocrine pancreas morphology and function during parenteral nutrition.

    PubMed

    Pierre, Joseph F; Neuman, Joshua C; Brill, Allison L; Brar, Harpreet K; Thompson, Mary F; Cadena, Mark T; Connors, Kelsey M; Busch, Rebecca A; Heneghan, Aaron F; Cham, Candace M; Jones, Elaina K; Kibbe, Carly R; Davis, Dawn B; Groblewski, Guy E; Kudsk, Kenneth A; Kimple, Michelle E

    2015-09-15

    Stimulation of digestive organs by enteric peptides is lost during total parental nutrition (PN). Here we examine the role of the enteric peptide bombesin (BBS) in stimulation of the exocrine and endocrine pancreas during PN. BBS protects against exocrine pancreas atrophy and dysfunction caused by PN. BBS also augments circulating insulin levels, suggesting an endocrine pancreas phenotype. While no significant changes in gross endocrine pancreas morphology were observed, pancreatic islets isolated from BBS-treated PN mice showed a significantly enhanced insulin secretion response to the glucagon-like peptide-1 (GLP-1) agonist exendin-4, correlating with enhanced GLP-1 receptor expression. BBS itself had no effect on islet function, as reflected in low expression of BBS receptors in islet samples. Intestinal BBS receptor expression was enhanced in PN with BBS, and circulating active GLP-1 levels were significantly enhanced in BBS-treated PN mice. We hypothesized that BBS preserved islet function indirectly, through the enteroendocrine cell-pancreas axis. We confirmed the ability of BBS to directly stimulate intestinal enteroid cells to express the GLP-1 precursor preproglucagon. In conclusion, BBS preserves the exocrine and endocrine pancreas functions during PN; however, the endocrine stimulation is likely indirect, through the enteroendocrine cell-pancreas axis.

  8. [Intestinal-brain axis. Neuronal and immune-inflammatory mechanisms of brain and intestine pathology].

    PubMed

    Bondarenko, V M; Riabichenko, E V

    2013-01-01

    Mutually directed connections between intestine and brain are implemented by endocrine, neural and immune systems and nonspecific natural immunity. Intestine micro flora as an active participant of intestine-brain axis not only influences intestine functions but also stimulates the development of CNS in perinatal period and interacts with higher nervous centers causing depression and cognitive disorders in pathology. A special role belongs to intestine microglia. Apart from mechanic (protective) and trophic functions for intestine neurons, glia implements neurotransmitter, immunologic, barrier and motoric functions in the intestine. An interconnection between intestine barrier function and hematoencephalic barrier regulation exists. Chronic endotoxinemia as a result of intestine barrier dysfunction forms sustained inflammation state in periventricular zone of the brain with consequent destabilization of hematoencephalic barriers and spread oF inflammation to other parts of the brain resulting in neurodegradation development.

  9. L-arginine stimulates CAT-1-mediated arginine uptake and regulation of inducible nitric oxide synthase for the growth of chick intestinal epithelial cells.

    PubMed

    Yuan, Chao; Zhang, Xiaoyun; He, Qiang; Li, Junming; Lu, Jianjun; Zou, Xiaoting

    2015-01-01

    L-arginine (L-Arg) uptake is mediated by members of cationic amino acid transporter (CAT) family and may coincide with the induction of nitric oxide synthases (NOS). The present study was conducted to investigate the extracellular concentrations of L-Arg regulating the CAT-1, CAT-4 and inducible NOS (iNOS) in chick intestinal epithelial cells. The cells were cultured for 4 days in Arg-free Dulbecco's modified Eagle's medium containing 10, 100, 200, 400, or 600 μM L-Arg. Cell viability, nitric oxide (NO) concentrations, uptake and metabolism of L-[3H]-Arg as well as expression of CAT-1, CAT-4, and iNOS were determined. Our results showed that L-Arg enhances cell growth with a maximal response at 10-400 μM. Addition of 100, 200, or 400 μM L-Arg increased the L-[3H]-Arg uptake, which was associated with greater conversion of L-[3H]-citrulline and NO production in comparison with 10 μM L-Arg group. Increasing extracellular concentrations of L-Arg from 10 to 400 μM dose dependently increased the levels of CAT-1 mRNA and protein, while no effect on CAT-4 mRNA abundance was found. Furthermore, supplementation of 100, 200, or 400 μM L-Arg upregulated the expression of iNOS mRNA, and the relative protein levels for iNOS in 200 and 400 μM L-Arg groups were higher than those in 10 and 100 μM L-Arg groups. Collectively, we conclude that the CAT-1 isoform plays a role in L-Arg uptake, and L-Arg-mediated elevation of NO via iNOS promotes the growth of chick intestinal epithelial cells.

  10. Depletion of substance P, neurokinin A and calcitonin gene-related peptide from the contralateral and ipsilateral caudal trigeminal nucleus following unilateral electrical stimulation of the trigeminal ganglion; a possible neurophysiological and neuroanatomical link to generalized head pain.

    PubMed

    Samsam, M; Coveñas, R; Csillik, B; Ahangari, R; Yajeya, J; Riquelme, R; Narváez, J A; Tramu, G

    2001-03-01

    Primary trigeminal neurons of the trigeminal ganglion (TG) innervate major parts of the face and head, including the dura. Electrical stimulation of the TG at specific parameters, can activate its nociceptive neurons and may serve as an experimental pain model. Markowitz [J. Neurosci. 7 (1987) 4129] reported that electrical stimulation of the trigeminal ganglion (TG) causes extravasation of plasma proteins from venules of the trigeminally innervated domain possibly due to the release of vasoactive substances. Neurogenic inflammation (vasodilatation, plasma protein extravasation, release of vasoactive peptides) in dura may serve as one of the possible pathomechanisms underlying vascular head pain [Moskowitz, Ann. Neurol. 16 (1984) 157]. We performed a unilateral electrical stimulation (7.5 Hz, 5 ms, 0.8-1.4 mA for 5 min) of the TG in rat, to induce a neurogenic inflammation in the peripheral trigeminal domain including the dura, looking for calcitonin gene related peptide (CGRP), substance P (SP) and neurokinin A (NKA) immunoreactivity (IR) in the caudal trigeminal nucleus (CTN) into which massive central trigeminal processes terminate. Here, we show patchy depletion(s) of CGRP-, SP- and NKA-IRs in the contralateral CTN of the rat in addition to their ipsilateral depletion. Such depletion is due to the release of these neuropeptides in the CTN leading to the activation of bilateral trigeminal nociceptive pathway. These data afford the possibility that under specific frequencies (which may roughly correlate to the intensity of the painful stimulus) and/or specific intensities (may correlate to specific areas of the peripheral trigeminal domain) of stimulation, activation of one side of the TG may activate bilateral trigeminal nociceptive pathway leading to the perception of an ill localized/generalized pain or headache rather than a unilateral one.

  11. Intestinal Parasitoses.

    ERIC Educational Resources Information Center

    Lagardere, Bernard; Dumburgier, Elisabeth

    1994-01-01

    Intestinal parasites have become a serious public health problem in tropical countries because of the climate and the difficulty of achieving efficient hygiene. The objectives of this journal issue are to increase awareness of the individual and collective repercussions of intestinal parasites, describe the current conditions of contamination and…

  12. Teduglutide ([Gly2]GLP-2) protects small intestinal stem cells from radiation damage.

    PubMed

    Booth, C; Booth, D; Williamson, S; Demchyshyn, L L; Potten, C S

    2004-12-01

    Glucagon-like peptide-2 and its dipeptidyl peptidase (DP-IV) resistant analogue teduglutide are trophic for the gastrointestinal epithelium. Exposure increases villus height and crypt size and results in increased overall intestinal weight. As these effects may be mediated through stimulation of the stem cell compartment, they may promote intestinal healing and act as potential anti-mucositis agents in patients undergoing cancer chemotherapy. A study was initiated to investigate the protective effects of teduglutide on the murine small intestinal epithelium following gamma-irradiation using the crypt microcolony assay as a measure of stem cell survival and functional competence. Teduglutide demonstrated intestinotrophic effects in both CD1 and BDF1 mouse strains. In BDF1 mice, subcutaneous injection of GLP-2 or teduglutide (0.2 mg/kg/day, b.i.d.) for 14 days increased intestinal weight by 28% and resulted in comparable increases in crypt size, villus height and area. Teduglutide given daily for 6 or 14 days prior to whole body, gamma-irradiation significantly increased crypt stem cell survival when compared with vehicle-treated controls. The mean levels of protection over a range of doses provided protection factors from 1.3 to 1.5. A protective effect was only observed when teduglutide was given before irradiation. These results suggest that teduglutide has the ability to modulate clonogenic stem cell survival in the small intestine and this may have a useful clinical application in the prevention of cancer therapy-induced mucositis.

  13. Interaction between gastric and upper small intestinal hormones in the regulation of hunger and satiety: ghrelin and cholecystokinin take the central stage.

    PubMed

    Stengel, Andreas; Taché, Yvette

    2011-06-01

    Several peptides are produced and released from endocrine cells scattered within the gastric oxyntic and the small intestinal mucosa. These peptide hormones are crucially involved in the regulation of gastrointestinal functions and food intake by conveying their information to central regulatory sites located in the brainstem as well as in the forebrain, such as hypothalamic nuclei. So far, ghrelin is the only known hormone that is peripherally produced in gastric X/A-like cells and centrally acting to stimulate food intake, whereas the suppression of feeding seems to be much more redundantly controlled by a number of gut peptides. Cholecystokinin produced in the duodenum is a well established anorexigenic hormone that interacts with ghrelin to modulate food intake indicating a regulatory network located at the first site of contact with nutrients in the stomach and upper small intestine. In addition, a number of peptides including leptin, urocortin 2, amylin and glucagon-like peptide 1 interact synergistically with CCK to potentiate its satiety signaling effect. New developments have led to the identification of additional peptides in X/A-like cells either derived from the pro-ghrelin gene by alternative splicing and posttranslational processing (obestatin) or a distinct gene (nucleobindin2/nesfatin-1) which have been investigated for their influence on food intake.

  14. Epidermal growth factor (EGF) inhibits stimulated thyroid hormone secretion in the mouse

    SciTech Connect

    Ahren, B.

    1987-07-01

    It is known that epidermal growth factor (EGF) inhibits iodide uptake in the thyroid follicular cells and lowers plasma levels of thyroid hormones upon infusion into sheep and ewes. In this study, the effects of EGF on basal and stimulated thyroid hormone secretion were investigated in the mouse. Mice were pretreated with /sup 125/I and thyroxine; the subsequent release of /sup 125/I is an estimation of thyroid hormone secretion. It was found that basal radioiodine secretion was not altered by intravenous injection of EGF (5 micrograms/animal). However, the radioiodine secretion stimulated by both TSH (120 microU/animal) and vasoactive intestinal peptide (VIP; 5 micrograms/animal) were inhibited by EGF (5 micrograms/animal). At a lower dose level (0.5 microgram/animal), EGF had no influence on stimulated radioiodine secretion. In conclusion, EGF inhibits stimulated thyroid hormone secretion in the mouse.

  15. High Fat Diet Alters Gut Microbiota and the Expression of Paneth Cell-Antimicrobial Peptides Preceding Changes of Circulating Inflammatory Cytokines

    PubMed Central

    Li, Jinchao; Tang, Renyong; Zhang, Guodong; Zeng, Huawei; Wood, Richard J.

    2017-01-01

    Obesity is an established risk factor for many diseases including intestinal cancer. One of the responsible mechanisms is the chronic inflammation driven by obesity. However, it remains to be defined whether diet-induced obesity exacerbates the intestinal inflammatory status by cytokines produced in adipose tissue or the high fat diet first alters the gut microbiota and then drives intestinal inflammation. To address this question, we fed C57BL/6 mice with a high fat diet (HF, 60%) and sacrificed them sequentially after 8, 12, and 16 weeks, and then compositions of gut microbiota and expressions of antimicrobial peptides were determined. The compositions of gut microbiota were altered at 8 wk HF feeding, followed with reduced Paneth antimicrobial peptides lysozyme and Reg IIIγ after 12 and 16 wk HF feeding (p < 0.05), whereas elevations of circulating inflammatory cytokines IFNγ and TNF-α were observed until feeding a HF diet for 16 weeks (p < 0.05). These results indicated that high fat diet may stimulate intestinal inflammation via altering gut microbiota, and it occurs prior to the potential influence by circulating inflammatory cytokines. These findings emphasized the importance of microbiota, in addition to adipose tissue per se, in driving intestinal inflammation, which may thereafter promote intestinal tumorigenesis. PMID:28316379

  16. High Fat Diet Alters Gut Microbiota and the Expression of Paneth Cell-Antimicrobial Peptides Preceding Changes of Circulating Inflammatory Cytokines.

    PubMed

    Guo, Xiulan; Li, Jinchao; Tang, Renyong; Zhang, Guodong; Zeng, Huawei; Wood, Richard J; Liu, Zhenhua

    2017-01-01

    Obesity is an established risk factor for many diseases including intestinal cancer. One of the responsible mechanisms is the chronic inflammation driven by obesity. However, it remains to be defined whether diet-induced obesity exacerbates the intestinal inflammatory status by cytokines produced in adipose tissue or the high fat diet first alters the gut microbiota and then drives intestinal inflammation. To address this question, we fed C57BL/6 mice with a high fat diet (HF, 60%) and sacrificed them sequentially after 8, 12, and 16 weeks, and then compositions of gut microbiota and expressions of antimicrobial peptides were determined. The compositions of gut microbiota were altered at 8 wk HF feeding, followed with reduced Paneth antimicrobial peptides lysozyme and Reg IIIγ after 12 and 16 wk HF feeding (p < 0.05), whereas elevations of circulating inflammatory cytokines IFNγ and TNF-α were observed until feeding a HF diet for 16 weeks (p < 0.05). These results indicated that high fat diet may stimulate intestinal inflammation via altering gut microbiota, and it occurs prior to the potential influence by circulating inflammatory cytokines. These findings emphasized the importance of microbiota, in addition to adipose tissue per se, in driving intestinal inflammation, which may thereafter promote intestinal tumorigenesis.

  17. [Effect of vasoactive intestinal peptide on defecation and VIP-cAMP-PKA-AQP3 signaling pathway 
in rats with constipation].

    PubMed

    Zhou, Yongxue; Wang, Yujin; Zhang, Hong; Yan, Shuguang; Wang, Bin; Xie, Pei

    2016-11-28

    目的:观察血管活性肠肽(vasoactive intestinal peptide,VIP)对便秘大鼠肠道水液代谢、环磷酸腺苷-蛋白激酶A信号通路(cyclic AMP protein kinase A signaling pathway,cAMP-PKA)和水通道蛋白3(water channel protein 3,AQP3)的影响,探讨VIP治疗便秘的作用及机制。方法:45只健康成年Sprague-Dawley大鼠随机分为空白对照组、模型组、模型+
VIP组。给药4周后,墨汁灌胃法检测大鼠首粒黑便排出时间;根据大鼠粪便干湿重计算粪便含水率;HE染色观察各组大鼠结肠组织形态学变化;Western 印迹检测各组大鼠结肠组织中 VIP和AQP3蛋白表达水平;定量即时聚合酶链锁反应(quantitative real time polymerase chain reaction,qPCR)检测各组大鼠结肠组织中cAMP,PKA和AQP3 mRNA的表达水平。结果:与空白对照组比较,模型组大鼠首粒黑便出现时间延长,粪便含水率明显减少(均P<0.01);结肠黏膜上皮部分破坏,杯状细胞体积减小,数量明显减少;结肠组织中VIP和AQP3蛋白含量明显减少,AQP3,cAMP和PKA mRNA相对表达水平均有所降低(均P<0.05)。与模型组比较,模型+VIP组大鼠首粒黑便出现时间缩短,粪便含水率明显增加(均P<0.05);结肠黏膜上皮完整性明显改善,杯状细胞体积增大,数量增多;结肠组织中VIP和 AQP3蛋白含量增多,CAMP,PKA和AQP3 mRNA相对表达水平升高(均P<0.05)。结论:VIP静脉注射能够调节肠道水液代谢,改善大鼠便秘症状,其机制可能与调节VIP-cAMP-PKA-AQP3信号通路有关。.

  18. Glucagon-like peptide-2 intracellularly stimulates eNOS phosphorylation and specifically induces submucosal arteriole vasodilation via a sheer stress-independent, local neural mechanism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glucagon-like peptide-2 (GLP-2) is a nutrient-responsive neuropeptide that exerts diverse actions in the gastrointestinal tract, including enhancing mucosal cell survival and proliferation, mucosal blood flow, luminal nutrient uptake, and suppressing gastric motility and secretion. We have shown th...

  19. Antimicrobial Peptides from Fish

    PubMed Central

    Masso-Silva, Jorge A.; Diamond, Gill

    2014-01-01

    Antimicrobial peptides (AMPs) are found widely distributed through Nature, and participate in the innate host defense of each species. Fish are a great source of these peptides, as they express all of the major classes of AMPs, including defensins, cathelicidins, hepcidins, histone-derived peptides, and a fish-specific class of the cecropin family, called piscidins. As with other species, the fish peptides exhibit broad-spectrum antimicrobial activity, killing both fish and human pathogens. They are also immunomodulatory, and their genes are highly responsive to microbes and innate immuno-stimulatory molecules. Recent research has demonstrated that some of the unique properties of fish peptides, including their ability to act even in very high salt concentrations, make them good potential targets for development as therapeutic antimicrobials. Further, the stimulation of their gene expression by exogenous factors could be useful in preventing pathogenic microbes in aquaculture. PMID:24594555

  20. Epidermal Growth Factor and Intestinal Barrier Function

    PubMed Central

    Liu, Hu; Yang, Shufen; Li, Zuohua; Zhong, Jinfeng

    2016-01-01

    Epidermal growth factor (EGF) is a 53-amino acid peptide that plays an important role in regulating cell growth, survival, migration, apoptosis, proliferation, and differentiation. In addition, EGF has been established to be an effective intestinal regulator helping to protect intestinal barrier integrity, which was essential for the absorption of nutrients and health in humans and animals. Several researches have demonstrated that EGF via binding to the EGF receptor and subsequent activation of Ras/MAPK, PI3K/AKT, PLC-γ/PKC, and STATS signal pathways regulates intestinal barrier function. In this review, the relationship between epidermal growth factor and intestinal development and intestinal barrier is described, to provide a better understanding of the effects of EGF on intestine development and health. PMID:27524860

  1. Autonomic Modification of Intestinal Smooth Muscle Contractility

    ERIC Educational Resources Information Center

    Montgomery, Laura E. A.; Tansey, Etain A.; Johnson, Chris D.; Roe, Sean M.; Quinn, Joe G.

    2016-01-01

    Intestinal smooth muscle contracts rhythmically in the absence of nerve and hormonal stimulation because of the activity of pacemaker cells between and within the muscle layers. This means that the autonomic nervous system modifies rather than initiates intestinal contractions. The practical described here gives students an opportunity to observe…

  2. Curcumin Ameliorates Reserpine-Induced Gastrointestinal Mucosal Lesions Through Inhibiting IκB-α/NF-κB Pathway and Regulating Expression of Vasoactive Intestinal Peptide and Gastrin in Rats.

    PubMed

    Long, Lingli; Wang, Jingnan; Chen, Ningning; Zheng, Shuhui; Shi, Lanying; Xu, Yuxia; Luo, Canqiao; Deng, Yubin

    2016-06-01

    The objective of our study was to investigate whether curcumin protects against reserpine-induced gastrointestinal mucosal lesions (GMLs) in rats and to explore the mechanism of curcumin's action. Sprague-Dawley rats were randomly divided into four groups: control group, reserpine-treated group, reserpine treatment group with curcumin at high dose (200 mg/kg), and reserpine treatment group with curcumin at low dose (100 mg/kg). Rats in reserpine-treated group were induced by intraperitoneally administered reserpine (0.5 mg/kg) for 28 days. TUNEL staining and hematoxylin and eosin staining were used to evaluate the apoptotic cells and morphologic changes. In addition, to explore the mechanism of curcumin in protecting GMLs, we used serum of experimental rats to assess the level of vasoactive intestinal peptide (VIP), gastrin, interleukin-6, interleukin-10, tumor necrosis factor-α and interferon-γ by ELISA and radioimmunoassay. The protein levels of NF-κB, p-IκB-α, IκB-α, Bcl-2, Bax, and cleaved-caspase-3 were examined by western blot analysis. Data were analyzed with SPSS 19.0 software package. Curcumin treatment prevented tissue damage and cell death in the reserpine-treated rats and effectively decreased inflammatory response and balanced the expression of VIP and gastrin in the reserpine-treated rats. NF-κB, p-IκB-α, Bax, and cleaved-caspase-3 were increased in the reserpine group, but the curcumin high-dose group inhibited them. Curcumin can target the IκB-α/NF-κB pathway to inhibit inflammatory response and regulate the level of VIP and gastrin in reserpine-induced GML rats.

  3. Long-acting glucagon-like peptide-1 receptor agonists have direct access to and effects on pro-opiomelanocortin/cocaine- and amphetamine-stimulated transcript neurons in the mouse hypothalamus.

    PubMed

    Knudsen, Lotte Bjerre; Secher, Anna; Hecksher-Sørensen, Jacob; Pyke, Charles

    2016-04-01

    Liraglutide is a glucagon-like peptide-1 receptor (GLP-1R) agonist marketed for the treatment of type 2 diabetes. Besides lowering blood glucose, liraglutide reduces bodyweight, and has recently also been approved for the obesity indication. Acutely, GLP-1 markedly reduces gastric emptying, and this effect was previously believed to at least partly explain the effect on bodyweight loss. However, recent studies in both humans and animals have shown that GLP-1R agonists, such as liraglutide, that lead to pharmacological concentrations for 24 h/day only have a minor effect on gastric emptying; such an effect is unlikely to have lasting effects on appetite reduction. Liraglutide has been shown to have direct effects in the arcuate nucleus of the rodent brain, activating pro-opiomelanocortin neurons and increasing levels of the cocaine- and amphetamine-stimulated transcript neuropeptide messenger ribonucleic acid, which correlate nicely to clinical studies where liraglutide was shown to increase feelings of satiety. However, despite the lack of a GLP-1R on agouti-related peptide/neuropeptide Y neurons, liraglutide also was able to prevent a hunger associated increase in agouti-related peptide and neuropeptide Y neuropeptide messenger ribonucleic acid, again with a strong correlation to clinical studies that document reduced hunger feelings in patients while taking liraglutide. Studies using fluorescent labeled liraglutide, as well as other GLP-1R agonists, and analysis using single-plane illumination microscopy show that such medium-sized peptide-based compounds can directly access not only circumventricular organs of the brain, but also directly access discrete regions in the hypothalamus. The direct effects of long-acting GLP-1R agonists in the hypothalamus are likely to be an important new pathway in understanding GLP-1R agonist mediated weight loss.

  4. Substitution of the Lys linker with the β-Ala linker dramatically decreased the renal uptake of 99mTc-labeled Arg-X-Asp-conjugated and X-Ala-Asp-conjugated α-melanocyte stimulating hormone peptides.

    PubMed

    Flook, Adam M; Yang, Jianquan; Miao, Yubin

    2014-11-13

    The purpose of this study was to examine whether the substitution of the Lys linker with the β-Ala could reduce the renal uptake of (99m)Tc-labeled Arg-X-Asp-conjugated and X-Ala-Asp-conjugated α-melanocyte stimulating hormone (α-MSH) peptides. RSD-β-Ala-(Arg(11))CCMSH (1) {c[Arg-Ser-Asp-dTyr-Asp]-β-Ala-Cys-Cys-Glu-His-dPhe-Arg-Trp-Cys-Arg-Pro-Val-NH2}, RTD-β-Ala-(Arg(11))CCMSH (2), RVD-β-Ala-(Arg(11))CCMSH (3), RAD-β-Ala-(Arg(11))CCMSH (4), NAD-β-Ala-(Arg(11))CCMSH (5), and EAD-β-Ala-(Arg(11))CCMSH (6) peptides were synthesized and evaluated for their melanocortin 1 (MC1) receptor binding affinities in B16/F1 melanoma cells. The biodistribution of their (99m)Tc-conjugates were determined in B16/F1 melanoma-bearing C57 mice. The substitution of the Lys linker with β-Ala linker dramatically reduced the renal uptake of all six (99m)Tc-peptides. (99m)Tc-4 exhibited the highest melanoma uptake (15.66 ± 6.19% ID/g) and the lowest kidney uptake (20.18 ± 3.86% ID/g) among these (99m)Tc-peptides at 2 h postinjection. The B16/F1 melanoma lesions could be clearly visualized by single photon emission computed tomography (SPECT)/CT using (99m)Tc-4 as an imaging probe.

  5. Interactions between opioid-peptides-containing pathways and GABA(A)-receptors-mediated systems modulate panic-like-induced behaviors elicited by electric and chemical stimulation of the inferior colliculus.

    PubMed

    Calvo, Fabrício; Coimbra, Norberto Cysne

    2006-08-09

    Aiming to clarify the effect of interactive interconnections between the endogenous opioid peptides-neural links and GABAergic pathways on panic-like responses, in the present work, the effect of the peripheral and central administration of morphine or the non-specific opioid receptors antagonist naloxone was evaluated on the fear-induced responses (defensive attention, defensive immobility and escape behavior) elicited by electric and chemical stimulation of the inferior colliculus. Central microinjections of opioid drugs in the inferior colliculus were also performed followed by local administration of the GABA(A)-receptor antagonist bicuculline. The defensive behavior elicited by the blockade of GABAergic receptors in the inferior colliculus had been quantitatively analyzed, recording the number of crossing, jump, rotation and rearing, in each minute, during 30 min, in the open-field test. The opioid receptors stimulation with morphine decreased the defensive attention, the defensive immobility and escape behavior thresholds, and the non-specific opioid receptors blockade caused opposite effects, enhancing the defensive behavior thresholds. These effects were corroborated by either the stimulation or the inhibition of opioid receptors followed by the GABA(A) receptor blockade with bicuculline, microinjected into the inferior colliculus. There was a significant increase in the diverse fear-induced responses caused by bicuculline with the pretreatment of the inferior colliculus with morphine, and the opposite effect was recorded after the pretreatment of the inferior colliculus nuclei with naloxone followed by bicuculline local administration. These findings suggest an interaction between endogenous opioid-peptides-containing connections and GABA(A)-receptor-mediated system with direct influence on the organization of the panic-like or fear-induced responses elaborated in the inferior colliculus during critical emotional states.

  6. Generation of L cells in mouse and human small intestine organoids.

    PubMed

    Petersen, Natalia; Reimann, Frank; Bartfeld, Sina; Farin, Henner F; Ringnalda, Femke C; Vries, Robert G J; van den Brink, Stieneke; Clevers, Hans; Gribble, Fiona M; de Koning, Eelco J P

    2014-02-01

    Upon a nutrient challenge, L cells produce glucagon-like peptide 1 (GLP-1), a powerful stimulant of insulin release. Strategies to augment endogenous GLP-1 production include promoting L-cell differentiation and increasing L-cell number. Here we present a novel in vitro platform to generate functional L cells from three-dimensional cultures of mouse and human intestinal crypts. We show that short-chain fatty acids selectively increase the number of L cells, resulting in an elevation of GLP-1 release. This is accompanied by the upregulation of transcription factors associated with the endocrine lineage of intestinal stem cell development. Thus, our platform allows us to study and modulate the development of L cells in mouse and human crypts as a potential basis for novel therapeutic strategies in patients with type 2 diabetes.

  7. Intestinal Capillariasis

    DTIC Science & Technology

    1987-12-01

    bhIll inenais, the tiny nematode causing Intestinal capillariasis In humans, Is a Iunique parasite. It is one of the newest parasites that has been...Capillariaphilippinensis, the tiny nematode causing intestinal capillariasis in humans, is a unique parasite. It is one of the newest parasites that has been shown to...stichocytes surrounding the oesophagus. The posterior half of the nematode is wider than the anterior half and contains the digestive tract and the

  8. Formulation strategies to improve oral peptide delivery.

    PubMed

    Maher, Sam; Ryan, Ben; Duffy, Aoife; Brayden, David J

    2014-05-01

    Delivery of peptides by the oral route greatly appeals due to commercial, patient convenience and scientific arguments. While there are over 60 injectable peptides marketed worldwide, and many more in development, most delivery strategies do not yet adequately overcome the barriers to oral delivery. Peptides are sensitive to chemical and enzymatic degradation in the intestine, and are poorly permeable across the intestinal epithelium due to sub-optimal physicochemical properties. A successful oral peptide delivery technology should protect potent peptides from presystemic degradation and improve epithelial permeation to achieve a target oral bioavailability with acceptable intra-subject variability. This review provides a comprehensive up-to-date overview of the current status of oral peptide delivery with an emphasis on patented formulations that are yielding promising clinical data.

  9. Whey proteins have beneficial effects on intestinal enteroendocrine cells stimulating cell growth and increasing the production and secretion of incretin hormones.

    PubMed

    Gillespie, Anna L; Calderwood, Danielle; Hobson, Laura; Green, Brian D

    2015-12-15

    Whey protein has been indicated to curb diet-induced obesity, glucose intolerance and delay the onset of type 2 diabetes mellitus. Here the effects of intact crude whey, intact individual whey proteins and beta-lactoglobulin hydrolysates on an enteroendocrine (EE) cell model were examined. STC-1 pGIP/neo cells were incubated with several concentrations of yogurt whey (YW), cheese whey (CW), beta-lactoglobulin (BLG), alpha-lactalbumin (ALA) and bovine serum albumin (BSA). The findings demonstrate that BLG stimulates EE cell proliferation, and also GLP-1 secretion (an effect which is lost following hydrolysis with chymotrypsin or trypsin). ALA is a highly potent GLP-1 secretagogue which also increases the intracellular levels of GLP-1. Conversely, whey proteins and hydrolysates had little impact on GIP secretion. This appears to be the first investigation of the effects of the three major proteins of YW and CW on EE cells. The anti-diabetic potential of whey proteins should be further investigated.

  10. Peptide IDR-1002 Inhibits NF-κB Nuclear Translocation by Inhibition of IκBα Degradation and Activates p38/ERK1/2–MSK1-Dependent CREB Phosphorylation in Macrophages Stimulated with Lipopolysaccharide

    PubMed Central

    Huante-Mendoza, Alejandro; Silva-García, Octavio; Oviedo-Boyso, Javier; Hancock, Robert E. W.; Baizabal-Aguirre, Víctor M.

    2016-01-01

    The inflammatory response is a critical molecular defense mechanism of the innate immune system that mediates the elimination of disease-causing bacteria. Repair of the damaged tissue, and the reestablishment of homeostasis, must be accomplished after elimination of the pathogen. The innate defense regulators (IDRs) are short cationic peptides that mimic natural host defense peptides and are effective in eliminating pathogens by enhancing the activity of the immune system while controlling the inflammatory response. Although the role of different IDRs as modulators of inflammation has been reported, there have been only limited studies of the signaling molecules regulated by this type of peptide. The present study investigated the effect of IDR-1002 on nuclear factor κB (NF-κB) and cAMP-response element-binding protein (CREB) transcription factors that are responsible for triggering and controlling inflammation, respectively, in macrophages. We found that TNF-α and COX-2 expression, IκBα phosphorylation, and NF-κB nuclear translocation were strongly inhibited in macrophages pre-incubated with IDR-1002 and then stimulated with lipopolysaccharide (LPS). IDR-1002 also increased CREB phosphorylation at Ser133 via activation of the p38/ERK1/2–MSK1 signaling pathways without detectable expression of the cytokines IL-4, IL-10, and IL-13 involved is suppressing inflammation or alternative activation. Transcriptional activation of NF-κB and CREB is known to require interaction with the transcriptional coactivator CREB-binding protein (CBP). To test for CBP–NF-κB and CBP–CREB complex formation, we performed co-immunoprecipitation assays. These assays showed that IDR-1002 inhibited the interaction between CBP and NF-κB in macrophages stimulated with LPS, which might explain the inhibition of TNF-α and COX-2 expression. Furthermore, the complex between CBP and CREB in macrophages stimulated with IDR-1002 was also inhibited, which might explain why IDR-1002 did

  11. The effect of gastric inhibitory polypeptide on intestinal glucose absorption and intestinal motility in mice

    SciTech Connect

    Ogawa, Eiichi; Hosokawa, Masaya; Harada, Norio; Yamane, Shunsuke; Hamasaki, Akihiro; Toyoda, Kentaro; Fujimoto, Shimpei; Fujita, Yoshihito; Fukuda, Kazuhito; Tsukiyama, Katsushi; Yamada, Yuichiro; Seino, Yutaka; Inagaki, Nobuya

    2011-01-07

    Research highlights: {yields} Exogenous GIP inhibits intestinal motility through a somatostatin-mediated pathway. {yields} Exogenous GIP inhibits intestinal glucose absorption by reducing intestinal motility. {yields} The GIP-receptor-mediated action in intestine does not involve in GLP-1-mediated pathway. -- Abstract: Gastric inhibitory polypeptide (GIP) is released from the small intestine upon meal ingestion and increases insulin secretion from pancreatic {beta} cells. Although the GIP receptor is known to be expressed in small intestine, the effects of GIP in small intestine are not fully understood. This study was designed to clarify the effect of GIP on intestinal glucose absorption and intestinal motility. Intestinal glucose absorption in vivo was measured by single-pass perfusion method. Incorporation of [{sup 14}C]-glucose into everted jejunal rings in vitro was used to evaluate the effect of GIP on sodium-glucose co-transporter (SGLT). Motility of small intestine was measured by intestinal transit after oral administration of a non-absorbed marker. Intraperitoneal administration of GIP inhibited glucose absorption in wild-type mice in a concentration-dependent manner, showing maximum decrease at the dosage of 50 nmol/kg body weight. In glucagon-like-peptide-1 (GLP-1) receptor-deficient mice, GIP inhibited glucose absorption as in wild-type mice. In vitro examination of [{sup 14}C]-glucose uptake revealed that 100 nM GIP did not change SGLT-dependent glucose uptake in wild-type mice. After intraperitoneal administration of GIP (50 nmol/kg body weight), small intestinal transit was inhibited to 40% in both wild-type and GLP-1 receptor-deficient mice. Furthermore, a somatostatin receptor antagonist, cyclosomatostatin, reduced the inhibitory effect of GIP on both intestinal transit and glucose absorption in wild-type mice. These results demonstrate that exogenous GIP inhibits intestinal glucose absorption by reducing intestinal motility through a somatostatin

  12. Insect peptide CopA3-induced protein degradation of p27Kip1 stimulates proliferation and protects neuronal cells from apoptosis

    SciTech Connect

    Nam, Seung Taek; Kim, Dae Hong; Lee, Min Bum; Nam, Hyo Jung; Kang, Jin Ku; Park, Mi Jung; Lee, Ik Hwan; Seok, Heon; Lee, Dong Gun; Hwang, Jae Sam; Kim, Ho

    2013-07-19

    Highlights: •CopA3 peptide isolated from the Korean dung beetle has antimicrobial activity. •Our study reported that CopA3 has anticancer and immunosuppressive effects. •We here demonstrated that CopA3 has neurotropic and neuroprotective effects. •CopA3 degrades p27Kip1 protein and this mediates effects of CopA3 on neuronal cells. -- Abstract: We recently demonstrated that the antibacterial peptide, CopA3 (a D-type disulfide dimer peptide, LLCIALRKK), inhibits LPS-induced macrophage activation and also has anticancer activity in leukemia cells. Here, we examined whether CopA3 could affect neuronal cell proliferation. We found that CopA3 time-dependently increased cell proliferation by up to 31 ± 2% in human neuroblastoma SH-SY5Y cells, and up to 29 ± 2% in neural stem cells isolated from neonatal mouse brains. In both cell types, CopA3 also significantly inhibited the apoptosis and viability losses caused by 6-hydroxy dopamine (a Parkinson disease-mimicking agent) and okadaic acid (an Alzheimer’s disease-mimicking agent). Immunoblotting revealed that the p27Kip1 protein (a negative regulator of cell cycle progression) was markedly degraded in CopA3-treated SH-SY5Y cells. Conversely, an adenovirus expressing p27Kip1 significantly inhibited the antiapoptotic effects of CopA3 against 6-hydroxy dopamine- and okadaic acid-induced apoptosis, and decreased the neurotropic effects of CopA3. These results collectively suggest that CopA3-mediated protein degradation of p27Kip1 may be the main mechanism through which CopA3 exerts neuroprotective and neurotropic effects.

  13. Inhibition of phospholipase D activation by CYL-26z in formyl peptide-stimulated neutrophils involves the blockade of RhoA activation.

    PubMed

    Kuan, Yu-Hsiang; Lin, Ruey-Hseng; Tsao, Lo-Ti; Chen, Yeh-Long; Tzeng, Cherng-Chyi; Wang, Jih-Pyang

    2005-09-15

    5-[4-Acridin-9-ylamino]phenyl]-5-methyl-3-methylenedihydrofuran-2-one (CYL-26z) inhibited the formyl-Met-Leu-Phe (fMLP)-stimulated phospholipase D (PLD) activity, which was assessed by the production of phosphatidylethanol (PEt) in the presence of ethanol, in rat neutrophils (IC50 1.2+/-0.2 microM). CYL-26z caused a slight but significant attenuation of the global protein tyrosine phosphorylation stimulated by fMLP only at concentrations of CYL-26z up to 30 microM. CYL-26z blocked the membrane recruitment of protein kinase C-alpha (PKC-alpha) at concentrations of CYL-26z > or =3 microM, but failed to affect the membrane association of PKC-betaI and -betaII. The translocation of RhoA to the membrane was attenuated by CYL-26z (IC50 3.8+/-0.8 microM) in fMLP-stimulated neutrophils, whereas CYL-26z caused no significant inhibition of the membrane recruitment of ADP-ribosylation factor (Arf). CYL-26z inhibited the activation of RhoA and dissociation of the RhoA-Rho guanine nucleotide dissociation inhibitor (GDI) complex in fMLP-stimulated neutrophils (IC50 1.8+/-1.0 microM and 1.8+/-0.9 microM, respectively). In a cell-free system, CYL-26z effectively attenuated the membrane association of RhoA in response to GTPgammaS (IC50 1.3+/-0.5 microM). In contrast, the GTPgammaS-stimulated translocation of Arf to membrane was suppressed only at concentrations of CYL-26z up to 30 microM. CYL-26z inhibited the fMLP-stimulated membrane expression of CD11b, CD45 and CD63, and the release of lysozyme and beta-glucuronidase. These results indicate that CYL-26z inhibited the fMLP-stimulated PLD activity, mainly through the blockade of RhoA activation, and degranulation in rat neutrophils.

  14. Helicobacter pylori HP(2-20) induces eosinophil activation and accumulation in superficial gastric mucosa and stimulates VEGF-alpha and TGF-beta release by interacting with formyl-peptide receptors.

    PubMed

    Prevete, N; Rossi, F W; Rivellese, F; Lamacchia, D; Pelosi, C; Lobasso, A; Necchi, V; Solcia, E; Fiocca, R; Ceppa, P; Staibano, S; Mascolo, M; D'Argenio, G; Romano, M; Ricci, V; Marone, G; De Paulis, A

    2013-01-01

    Eosinophils participate in the immune response against Helicobacter pylori, but little is known about their role in the gastritis associated to the infection. We recently demonstrated that the Hp(2-20) peptide derived from H. pylori accelerates wound healing of gastric mucosa by interacting with N-formyl peptide receptors (FPRs) expressed on gastric epithelial cells. The aim of the present study was to investigate whether eosinophils play a role in the repair of gastric mucosa tissue during H. pylori infection. Immuno-histochemistry and transmission electron microscopy were used to detect eosinophils in gastric mucosal biopsies. Eosinophil re-distribution occurred in the gastric mucosa of H. pylori-infected patients: their density did not change in the deep mucosal layer, whereas it increased in the superficial lamina propria just below the foveolar epithelium; eosinophils entered the epithelium itself as well as the lumen of foveolae located close to the area harboring bacteria, which in turn were also engulfed by eosinophils. The H. pylori-derived peptide Hp(2-20) stimulated eosinophil migration through the engagement of FPR2 and FPR3, and also induced production of VEGF-A and TGF-beta, two key mediators of tissue remodelling. We also demonstrate that Hp(2-20) in vivo induced eosinophil infiltration in rat gastric mucosa after injury brought about by indomethacin. This study suggests that eosinophil infiltrate could modulate the capacity of gastric mucosa to maintain or recover its integrity thereby shedding light on the role of eosinophils in H. pylori infection.

  15. Treatment of both native and deamidated gluten peptides with an endo-peptidase from Aspergillus niger prevents stimulation of gut-derived gluten-reactive T cells from either children or adults with celiac disease.

    PubMed

    Toft-Hansen, Henrik; Rasmussen, Karina S; Staal, Anne; Roggen, Erwin L; Sollid, Ludvig M; Lillevang, Søren T; Barington, Torben; Husby, Steffen

    2014-08-01

    Celiac disease (CD) is characterized by an inappropriate immunological reaction against gluten driven by gluten-specific CD4+ T cells. We screened 25 proteases and tested 10 for their potential to degrade gluten in vitro. Five proteases were further tested for their ability to prevent the proliferative response by a gluten-specific CD4+ T cell clone and seven gluten-reactive T cell lines to protease-digested gluten peptides. A proline-specific endo-peptidase from Aspergillus niger (AnP2) was particularly efficient at diminishing proliferation after stimulation with cleaved antigen, and could completely block the response against both native and deamidated gluten peptides. We found that AnP2 was efficient down to a 1:64 protease:substrate ratio (w:w). When AnP2 was tested in assays using seven gluten-reactive T cell lines from individual CD patients (three adults and four children), the response to gluten was diminished in all cases. Our study indicates a therapeutic benefit of AnP2 to CD patients.

  16. Structure-Activity Relationships of the Competence Stimulating Peptides (CSPs) in Streptococcus pneumoniae Reveal Motifs Critical for Intra-group and Cross-group ComD Receptor Activation.

    PubMed

    Yang, Yifang; Koirala, Bimal; Sanchez, Lucia A; Phillips, Naiya R; Hamry, Sally R; Tal-Gan, Yftah

    2017-03-10

    Streptococcus pneumoniae is a highly recombinogenic human pathogen that utilizes the competence stimulating peptide (CSP)-based quorum sensing (QS) circuitry to acquire antibiotic resistance genes from the environment and initiate its attack on the human host. Modulation of QS in this bacterium, either inhibition or activation, can therefore be used to attenuate S. pneumoniae infectivity and slow down pneumococcal resistance development. In this study, we set to determine the molecular mechanism that drives CSP:receptor binding and identify CSP-based QS modulators with distinct activity profiles. To this end, we conducted systematic replacement of the amino acid residues in the two major CSP signals (CSP1 and CSP2) and assessed the ability of the mutated analogs to modulate QS against both cognate and noncognate ComD receptors. We then evaluated the overall 3D structures of these analogs using circular dichroism (CD) to correlate between the structure and function of these peptides. Our CD analysis revealed a strong correlation between α-helicity and bioactivity for both specificity groups (CSP1 and CSP2). Furthermore, we identified the first pan-group QS activator and the most potent group-II QS inhibitor to date. These chemical probes can be used to study the role of QS in S. pneumoniae and as scaffolds for the design of QS-based anti-infective therapeutics against S. pneumoniae infections.

  17. When the leader gets loose: in vivo biosynthesis of a leaderless prenisin is stimulated by a trans-acting leader peptide.

    PubMed

    Khusainov, Rustem; Kuipers, Oscar P

    2012-11-05

    The nisin leader is believed to be crucial for nisin biosynthesis. Here, by using a construct completely lacking the leader peptide, we show that an up to fivefold-dehydrated leaderless prenisin can be obtained, as judged by MALDI-TOF MS, and that some of these species are biologically active, thus suggesting that at least three lanthionine rings are present. Notably, by expressing the leader peptide in trans together with the leaderless prenisin, we were able to increase the dehydration/cyclization efficiency of both NisB and NisC, but still with limited efficiency until the fifth dehydratable residue (Thr13) was processed, thereby enabling three rings to form. This, for the first time, demonstrates that 1) the leader is not absolutely necessary for the dehydration reaction of class I lantibiotics to occur in vivo; 2) the leader acts in trans in vivo; 3) the leader increases the efficiency of modification. Based on previous work and our current study, a model for the interactions of NisB and NisC with prenisin is proposed, in which the leader induces a more active conformation and/or productive complex formation of the biosynthetic machinery, and, when covalently bound, is involved in increasing the efficiency of dehydration to the C-terminal end of the prenisin substrate molecule.

  18. Insect peptide CopA3-induced protein degradation of p27Kip1 stimulates proliferation and protects neuronal cells from apoptosis.

    PubMed

    Nam, Seung Taek; Kim, Dae Hong; Lee, Min Bum; Nam, Hyo Jung; Kang, Jin Ku; Park, Mi Jung; Lee, Ik Hwan; Seok, Heon; Lee, Dong Gun; Hwang, Jae Sam; Kim, Ho

    2013-07-19

    We recently demonstrated that the antibacterial peptide, CopA3 (a D-type disulfide dimer peptide, LLCIALRKK), inhibits LPS-induced macrophage activation and also has anticancer activity in leukemia cells. Here, we examined whether CopA3 could affect neuronal cell proliferation. We found that CopA3 time-dependently increased cell proliferation by up to 31 ± 2% in human neuroblastoma SH-SY5Y cells, and up to 29 ± 2% in neural stem cells isolated from neonatal mouse brains. In both cell types, CopA3 also significantly inhibited the apoptosis and viability losses caused by 6-hydroxy dopamine (a Parkinson disease-mimicking agent) and okadaic acid (an Alzheimer's disease-mimicking agent). Immunoblotting revealed that the p27Kip1 protein (a negative regulator of cell cycle progression) was markedly degraded in CopA3-treated SH-SY5Y cells. Conversely, an adenovirus expressing p27Kip1 significantly inhibited the antiapoptotic effects of CopA3 against 6-hydroxy dopamine- and okadaic acid-induced apoptosis, and decreased the neurotropic effects of CopA3. These results collectively suggest that CopA3-mediated protein degradation of p27Kip1 may be the main mechanism through which CopA3 exerts neuroprotective and neurotropic effects.

  19. Signalling pathways involved in the detection of peptones by murine small intestinal enteroendocrine L-cells

    PubMed Central

    Pais, Ramona; Gribble, Fiona M; Reimann, Frank

    2016-01-01

    Glucagon like peptide-1 is an insulinotropic hormone released from intestinal L-cells in response to food ingestion. Here, we investigated mechanisms underlying the sensing of peptones by primary small intestinal L-cells. Meat, casein and vegetable-derived peptones (5 mg/ml), the L-amino acids Phe, Trp, Gln and Ala (20 mM each), and the dipeptide glycine-sarcosine (20 mM) stimulated GLP-1 secretion from primary cultures prepared from the small intestine. Further mechanistic studies were performed with meat peptone, and revealed the elevation of intracellular calcium in L-cells. Inhibition of the calcium sensing receptor (CaSR), transient receptor potential (TRP) channels and Q-type voltage gated calcium channels (VGCC) significantly attenuated peptone-stimulated GLP-1 release and reduced intracellular Ca2+ responses. CaSR inhibition also attenuated the GLP-1 secretory response to Gln. Targeting these pathways in L-cells could be used to increase endogenous production of GLP-1 and offer exploitable avenues for the development of therapeutics to treat diabetes and obesity. PMID:26215048

  20. The intestinal lesion of autistic spectrum disorder.

    PubMed

    Jass, Jeremy R

    2005-08-01

    This editorial briefly reviews the significance of lymphoid nodular hyperplasia in the intestinal tract of children with autistic spectrum disorder. The distinction between physiological and pathological lymphoid hyperplasia of the intestinal tract is of importance in the context of a possible causative link with autism. A primary intestinal lesion may occur as part of the broad spectrum of immunological disorders to which autistic children are prone. This could result in increased intestinal permeability to peptides of dietary origin which may then lead to disruption of neuroregulatory mechanisms required for normal brain development. Alternatively, there could be a primary defect in the translocation and processing of factors derived from the intestinal lumen. These possibilities deserve further investigation and should not be lost in the fog of the controversy regarding the role of measles/mumps/rubella vaccination in the aetiology of autistic spectrum disorder.

  1. Nutrient-induced glucagon like peptide-1 release is modulated by serotonin.

    PubMed

    Ripken, Dina; van der Wielen, Nikkie; Wortelboer, Heleen M; Meijerink, Jocelijn; Witkamp, Renger F; Hendriks, Henk F J

    2016-06-01

    Glucagon like peptide-1 (GLP-1) and serotonin are both involved in food intake regulation. GLP-1 release is stimulated upon nutrient interaction with G-protein coupled receptors by enteroendocrine cells (EEC), whereas serotonin is released from enterochromaffin cells (ECC). The central hypothesis for the current study was that nutrient-induced GLP-1 release from EECs is modulated by serotonin through a process involving serotonin receptor interaction. This was studied by assessing the effects of serotonin reuptake inhibition by fluoxetine on nutrient-induced GLP-1, PYY and CCK release from isolated pig intestinal segments. Next, serotonin-induced GLP-1 release was studied in enteroendocrine STC-1 cells, where effects of serotonin receptor inhibition were studied using specific and non-specific antagonists. Casein (1% w/v), safflower oil (3.35% w/v), sucrose (50mM) and rebaudioside A (12.5mM) stimulated GLP-1 release from intestinal segments, whereas casein only stimulated PYY and CCK release. Combining nutrients with fluoxetine further increased nutrient-induced GLP-1, PYY and CCK release. Serotonin release from intestinal tissue segments was stimulated by casein and safflower oil while sucrose and rebaudioside A had no effect. The combination with fluoxetine (0.155μM) further enhanced casein and safflower oil induced-serotonin release. Exposure of ileal tissue segments to serotonin (30μM) stimulated GLP-1 release whereas it did not induce PYY and CCK release. Serotonin (30 and 100μM) also stimulated GLP-1 release from STC-1 cells, which was inhibited by the non-specific 5HT receptor antagonist asenapine (1 and 10μM). These data suggest that nutrient-induced GLP-1 release is modulated by serotonin through a receptor mediated process.

  2. Regulation and therapeutic targeting of peptide-activated receptor guanylyl cyclases.

    PubMed

    Potter, Lincoln R

    2011-04-01

    Cyclic GMP is a ubiquitous second messenger that regulates a wide array of physiologic processes such as blood pressure, long bone growth, intestinal fluid secretion, phototransduction and lipolysis. Soluble and single-membrane-spanning enzymes called guanylyl cyclases (GC) synthesize cGMP. In humans, the latter group consists of GC-A, GC-B, GC-C, GC-E and GC-F, which are also known as NPR-A, NPR-B, StaR, Ret1-GC and Ret2-GC, respectively. Membrane GCs are activated by peptide ligands such as atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), C-type natriuretic peptide (CNP), guanylin, uroguanylin, heat stable enterotoxin and GC-activating proteins. Nesiritide and carperitide are clinically approved peptide-based drugs that activate GC-A. CD-NP is an experimental heart failure drug that primarily activates GC-B but also activates GC-A at high concentrations and is resistant to degradation. Inactivating mutations in GC-B cause acromesomelic dysplasia type Maroteaux dwarfism and chromosomal mutations that increase CNP concentrations are associated with Marfanoid-like skeletal overgrowth. Pump-based CNP infusions increase skeletal growth in a mouse model of the most common type of human dwarfism, which supports CNP/GC-B-based therapies for short stature diseases. Linaclotide is a peptide activator of GC-C that stimulates intestinal motility and is in late-stage clinical trials for the treatment of chronic constipation. This review discusses the discovery of cGMP, guanylyl cyclases, the general characteristics and therapeutic applications of GC-A, GC-B and GC-C, and emphasizes the regulation of transmembrane guanylyl cyclases by phosphorylation and ATP.

  3. Fermented milk with probiotic Lactobacillus rhamnosus S1K3 (MTCC5957) protects mice from salmonella by enhancing immune and nonimmune protection mechanisms at intestinal mucosal level.

    PubMed

    Kemgang, Tanedjeu Sonfack; Kapila, Suman; Shanmugam, Venkatesa Perumal; Reddi, Srinu; Kapila, Rajeev

    2016-04-01

    We investigated the mechanism by which an Indian indigenous probiotic culture, Lactobacillus rhamnosus S1K3, could overcome the pathogenic strain Salmonella enterica with an emphasis on the response at the intestinal mucosal level after long-term (30days) consumption. S1K3 was able to produce antimicrobial compounds against the pathogens. The probiotic adhered strongly to intestinal epithelium and maintained its integrity in presence of Salmonella through stimulation of tight junction and antimicrobial peptide genes in vitro. Mice prefed for 30days with S1K3-fermented milk exhibited low incidence of pathogenic Salmonella at mucosal and systemic levels. The probiotic induced TLRs transcripts at the Peyer's patches, followed by an increase in the Secretory-IgA in intestinal fluid, the IgA-secreting cells in lamina propria of small intestine and the IgA level in serum. Moreover, S1K3 maintained the protein level of IL-12, increased the IL-4 and reduced the TGF-β level in intestinal fluid/serum at the later stage of infection. All these actions concurred to lower the count of Salmonella in feces, its invasion in spleen, liver and intestine tissues and improved the health status of probiotic-fed group. In view of this performance, S1K3 appears to be a suitable candidate for the development of nutraceutical food.

  4. Endothelin system in intestinal villi: A possible role of endothelin-2/vasoactive intestinal contractor in the maintenance of intestinal architecture.

    PubMed

    Bianchi, Mariana; Adur, Javier; Takizawa, Satoshi; Saida, Kaname; Casco, Víctor H

    2012-01-27

    The endothelin system consists of three ligands (ET-1, ET-2 and ET-3) and at least two receptors (ETA and ETB). In mice ET-2 counterpart is a peptide originally called "vasoactive intestinal contractor" (VIC) for this reason, this peptide is frequently named ET-2/VIC. In intestinal villi, fibroblasts-like cells express endothelin's receptors and response to ET-1 and ET-3 peptides, changing their cellular shape. Several functions have been attributed to these peptides in the "architecture" maintenance of intestinal villi acting over sub-epithelial fibroblasts. Despite this, ET-2/VIC has not been analyzed in depth. In this work we show the intestine gene expression and immunolocalization of ET-1, ET-2 and the ETA and ETB receptors from duodenum to rectus and in the villus-crypt axis in mice, allowing a complete analysis of their functions. While ET-1 is expressed uniformly, ET-2 had a particular distribution, being higher at the bottom of the villi of duodenum, ileum and jejunum and reverting this pattern in the crypts of colon and rectus, where the higher expression was at the top. We postulated that ET-2 would act in a cooperative manner with ET-1, giving to the villus the straight enough to withstand mechanical stress.

  5. Oral Delivery of Pentameric Glucagon-Like Peptide-1 by Recombinant Lactobacillus in Diabetic Rats

    PubMed Central

    Krogh-Andersen, Kasper; Pelletier, Julien; Marcotte, Harold; Östenson, Claes-Göran; Hammarström, Lennart

    2016-01-01

    Glucagon-like peptide-1 (GLP-1) is an incretin hormone produced by intestinal cells and stimulates insulin secretion from the pancreas in a glucose-dependent manner. Exogenously supplied GLP-1 analogues are used in the treatment of type 2 diabetes. An anti-diabetic effect of Lactobacillus in lowering plasma glucose levels and its use as a vehicle for delivery of protein and antibody fragments has been shown previously. The aim of this study was to employ lactobacilli as a vehicle for in situ production and delivery of GLP-1 analogue to normalize blood glucose level in diabetic GK (Goto-Kakizaki) rats. In this study, we designed pentameric GLP-1 (5×GLP-1) analogues which were both expressed in a secreted form and anchored to the surface of lactobacilli. Intestinal trypsin sites were introduced within 5×GLP-1, leading to digestion of the pentamer into an active monomeric form. The E. coli-produced 5×GLP-1 peptides delivered by intestinal intubation to GK rats resulted in a significant improvement of glycemic control demonstrated by an intraperitoneal glucose tolerance test. Meanwhile, the purified 5×GLP-1 (trypsin-digested) from the Lactobacillus cultures stimulated insulin secretion from HIT-T15 cells, similar to the E. coli-produced 5×GLP-1 peptides. When delivered by gavage to GK rats, non-expressor L. paracasei significantly lowered the blood glucose level but 5×GLP-1 expression did not provide an additional anti-diabetic effect, possibly due to the low levels produced. Our results indicate that lactobacilli themselves might be used as an alternative treatment method for type 2 diabetes, but further work is needed to increase the expression level of GLP-1 by lactobacilli in order to obtain a significant insulinotropic effect in vivo. PMID:27610615

  6. Gastric peptides and their regulation of hunger and satiety.

    PubMed

    Stengel, Andreas; Taché, Yvette

    2012-12-01

    Ingestion of food affects the secretion of hormones from specialized endocrine cells scattered within the intestinal mucosa. Upon release, these hormones mostly decrease food intake by signaling information to the brain. Although enteroendocrine cells in the small intestine were thought to represent the predominant gut-brain regulators of food intake, recent advances also established a major role for gastric hormones in these regulatory pathways. First and foremost, the gastric endocrine X/A-like cell was in the focus of many studies due to the production of ghrelin, which is until now the only known orexigenic hormone that is peripherally produced and centrally acting. Although X/A-cells were initially thought to only release one hormone that stimulates food intake, this view has changed with the identification of additional peptide products also derived from this cell, namely desacyl ghrelin, obestatin, and nesfatin-1. Desacyl ghrelin may play a counter-regulatory role to the food intake stimulatory effect of ghrelin. The same property was suggested for obestatin; however, this hypothesis could not be confirmed in numerous subsequent studies. Moreover, the description of the stomach as the major source of the novel anorexigenic hormone nesfatin-1 derived from the NUCB2 gene further corroborated the assumption that the gastric X/A-like cell products are not only stimulant but also inhibitors of feeding, thereby acting as so far unique dual regulator of food intake located in a logistically important place where the gastrointestinal tract has initial contact with food.

  7. Endotoxin-Binding Peptides Derived from Casein Glycomacropeptide Inhibit Lipopolysaccharide-Stimulated Inflammatory Responses via Blockade of NF-κB activation in macrophages

    PubMed Central

    Cheng, Xue; Gao, Dongxiao; Chen, Bin; Mao, Xueying

    2015-01-01

    Systemic low-grade inflammation and increased circulating lipopolysaccharide (LPS) contribute to metabolic dysfunction. The inhibitory effects and underlying molecular mechanisms of casein glycomacropeptide (GMP) hydrolysate on the inflammatory response of LPS-stimulated macrophages were investigated. Results showed that the inhibitory effect of GMP hydrolysates obtained with papain on nitric oxide (NO) production were obviously higher than that of GMP hydrolysates obtained with pepsin, alcalase and trypsin (p < 0.05), and the hydrolysate obtained with papain for 1 h hydrolysis (GHP) exhibited the highest inhibitory effect. Compared with native GMP, GHP markedly inhibited LPS-induced NO production in a dose-dependent manner with decreased mRNA level of inducible nitric oxide synthase (iNOS). GHP blocked toll-like receptor 4 (TLR4)/myeloid differentiation primary response 88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway activation, accompanied by downregulation of LPS-triggered significant upregulation of tumor necrosis factor (TNF)-α and interleukin (IL)-1β gene expression. Furthermore, GHP could neutralize LPS not only by direct binding to LPS, but also by inhibiting the engagement of LPS with the TLR4/MD2 complex, making it a potential LPS inhibitor. In conclusion, these findings suggest that GHP negatively regulates TLR4-mediated inflammatory response in LPS-stimulated RAW264.7 cells, and therefore may hold potential to ameliorate inflammation-related issues. PMID:25923657

  8. The natriuretic peptides BNP and CNP increase heart rate and electrical conduction by stimulating ionic currents in the sinoatrial node and atrial myocardium following activation of guanylyl cyclase-linked natriuretic peptide receptors.

    PubMed

    Springer, Jeremy; Azer, John; Hua, Rui; Robbins, Courtney; Adamczyk, Andrew; McBoyle, Sarah; Bissell, Mary Beth; Rose, Robert A

    2012-05-01

    Natriuretic peptides (NPs) are best known for their ability to regulate blood vessel tone and kidney function whereas their electrophysiological effects on the heart are less clear. Here, we measured the effects of BNP and CNP on sinoatrial node (SAN) and atrial electrophysiology in isolated hearts as well as isolated SAN and right atrial myocytes from mice. BNP and CNP dose-dependently increased heart rate and conduction through the heart as indicated by reductions in R-R interval, P wave duration and P-R interval on ECGs. In conjunction with these ECG changes BNP and CNP (100 nM) increased spontaneous action potential frequency in isolated SAN myocytes by increasing L-type Ca(2+) current (I(Ca,L)) and the hyperpolarization-activated current (I(f)). BNP had no effect on right atrial myocyte APs in basal conditions; however, in the presence of isoproterenol (10nM), BNP increased atrial AP duration and I(Ca,L). Quantitative gene expression and immunocytochemistry data show that all three NP receptors (NPR-A, NPR-B and NPR-C) are expressed in the SAN and atrium. The effects of BNP and CNP on SAN and right atrial myocytes were maintained in mutant mice lacking functional NPR-C receptors and blocked by the NPR-A antagonist A71915 indicating that BNP and CNP function through their guanylyl cyclase-linked receptors. Our data also show that the effects of BNP and CNP are completely absent in the presence of the phosphodiesterase 3 inhibitor milrinone. Based on these data we conclude that NPs can increase heart rate and electrical conduction by activating the guanylyl cyclase-linked NPR-A and NPR-B receptors and inhibiting PDE3 activity.

  9. Glucagon-like Peptide-1 (GLP-1) Analogs: Recent Advances, New Possibilities, and Therapeutic Implications

    PubMed Central

    2015-01-01

    Glucagon-like peptide-1 (GLP-1) is an incretin that plays important physiological roles in glucose homeostasis. Produced from intestine upon food intake, it stimulates insulin secretion and keeps pancreatic β-cells healthy and proliferating. Because of these beneficial effects, it has attracted a great deal of attention in the past decade, and an entirely new line of diabetic therapeutics has emerged based on the peptide. In addition to the therapeutic applications, GLP-1 analogs have demonstrated a potential in molecular imaging of pancreatic β-cells; this may be useful in early detection of the disease and evaluation of therapeutic interventions, including islet transplantation. In this Perspective, we focus on GLP-1 analogs for their studies on improvement of biological activities, enhancement of metabolic stability, investigation of receptor interaction, and visualization of the pancreatic islets. PMID:25349901

  10. Substitution of Gly with Ala enhanced the melanoma uptake of technetium-99m-labeled Arg-Ala-Asp-conjugated alpha-melanocyte stimulating hormone peptide.

    PubMed

    Yang, Jianquan; Miao, Yubin

    2012-02-15

    The purpose of this study was to determine the melanoma targeting property of (99m)Tc-RAD-Lys-(Arg(11))CCMSH in B16/F1 melanoma-bearing C57 mice and compare with (99m)Tc-RGD-Lys-(Arg(11))CCMSH we previously reported. (99m)Tc-RAD-Lys-(Arg(11))CCMSH exhibited rapid and high tumor uptake (19.91±4.02% ID/g at 2h post-injection) in B16/F1 melanoma-bearing C57 mice. The tumor uptake of (99m)Tc-RAD-Lys-(Arg(11))CCMSH was 1.51, 1.34 and 1.43 times the tumor uptake of (99m)Tc-RGD-Lys-(Arg(11))CCMSH at 0.5, 2 and 4h post-injection, respectively. Flank B16/F1 melanoma lesions were clearly imaged at 2h post-injection using (99m)Tc-RAD-Lys-(Arg(11))CCMSH as an imaging probe. The substitution of Gly with Ala significantly enhanced the melanoma uptake of (99m)Tc-RAD-Lys-(Arg(11))CCMSH compared to (99m)Tc-RGD-Lys-(Arg(11))CCMSH in B16/F1 melanoma-bearing C57 mice, providing a new insight into the design of α-MSH peptides for melanoma targeting.

  11. Role of calcitonin gene-related peptide in the sensitization of dorsal horn neurons to mechanical stimulation after intradermal injection of capsaicin.

    PubMed

    Sun, Rui-Qing; Lawand, Nada B; Lin, Qing; Willis, William D

    2004-07-01

    This study was designed to assess the role of calcitonin gene-related peptide (CGRP) and its receptor in the sensitization of dorsal horn neurons induced by intradermal injection of capsaicin in rats. Extracellular recordings were made from wide dynamic range (WDR) dorsal horn neurons with receptive fields on the hindpaw in the lumbar enlargement of anesthetized rats. The background activity and responses to brushing, pressing, and pinching the skin were assessed. A postsuperfusion or a presuperfusion of CGRP(8-37) paradigm was followed. When tested 30 min after capsaicin injection, there was an increase in background activity and responses to brush, press, and pinch applied to the receptive field. Superfusion of CGRP(8-37) into the spinal cord at 45 min after capsaicin injection significantly reversed the increased background activity and responses to brush, press, and pinch applied to the receptive field. On the other hand, spinal superfusion of CGRP(8-37) prior to capsaicin injection prevented the increased background activity and responses to brush, press, and pinch of WDR neurons that occurred following capsaicin injection in control experiments. A sensitization of spinal dorsal horn neurons could also be induced by superfusion of the spinal cord with CGRP. The effect could be blocked by CGRP(8-37) dose-dependently. Collectively, these results suggest that CGRP and its receptors are involved in the spinal cord central sensitization induced by intradermal injection of capsaicin.

  12. TLR2 ligand-synthetic long peptide conjugates effectively stimulate tumor-draining lymph node T cells of cervical cancer patients

    PubMed Central

    Zom, Gijs G.; Welters, Marij J.P.; Loof, Nikki M.; Goedemans, Renske; Lougheed, Sinéad; Valentijn, Rob R.P.M.; Zandvliet, Maarten L.; Meeuwenoord, Nico J.; Melief, Cornelis J.M.; de Gruijl, Tanja D.; Van der Marel, Gijsbert A.; Filippov, Dmitri V.

    2016-01-01

    The potency of human papillomavirus type 16 (HPV16)-encoded synthetic long peptides (SLP), conjugated to an optimized Toll-like receptor 2 ligand (TLR2-L), was assessed in ex vivo activation of HPV16+ cancer patient-derived T cells. Two highly immunogenic SLP sequences derived from the oncogenic E6 protein of HPV16 were selected and conjugated to a Pam3CSK4-based TLR2-L under GMP conditions. Both conjugates were able to mature human DCs in vitro and to activate human skin-derived antigen-presenting cells (APCs) upon intradermal injection in an ex vivo skin model, associated with induction of a favorable chemokine profile to attract and activate T cells. The conjugated SLPs were efficiently processed by APCs, since HPV16-specific CD4+ and CD8+ T-cell clones isolated from HPV16+ cervical tumors proliferated in response to both conjugates. The TLR2-L SLP conjugates significantly enhanced ex vivo T helper type 1 T-cell activation in cell suspensions obtained from tumor-draining lymph nodes (LN) resected during hysterectomy of HPV16+ cervical cancer patients. These results show that TLR2-L SLP conjugates can activate circulating or LN-derived tumor-specific T cells, a promising outcome for studying these two conjugates in a phase I/II clinical safety and immunogenicity trial. PMID:27564262

  13. Hydrogen peroxide stimulates proliferation and migration of human prostate cancer cells through activation of activator protein-1 and up-regulation of the heparin affin regulatory peptide gene.

    PubMed

    Polytarchou, Christos; Hatziapostolou, Maria; Papadimitriou, Evangelia

    2005-12-09

    It is becoming increasingly recognized that hydrogen peroxide (HP) plays a role in cell proliferation and migration. In the present study we found that exogenous HP significantly induced human prostate cancer LNCaP cell proliferation and migration. Heparin affin regulatory peptide (HARP) seems to be involved in the stimulatory effect of HP, because the latter had no effect on stably transfected LNCaP cells that did not express HARP. Moreover, HP significantly increased HARP mRNA and protein amounts in a concentration- and time-dependent manner. Curcumin and activator protein-1 (AP-1) decoy oligonucleotides abrogated both HP-induced HARP expression and LNCaP cell proliferation and migration. HP increased luciferase activity of the 5'-flanking region of the HARP gene introduced in a reporter gene vector, an effect that was abolished when even one of the two putative AP-1 binding sites of the HARP promoter was mutated. The effect of HP seems to be due to the binding of Fra-1, JunD, and phospho-c-Jun to the HARP promoter. These results support the notion that HARP is important for human prostate cancer cell proliferation and migration, establish the role of AP-1 in the up-regulation of HARP expression by low concentrations of HP, and characterize the AP-1 dimers involved.

  14. Calcitonin gene-related peptide as inflammatory mediator.

    PubMed

    Springer, Jochen; Geppetti, Pierangelo; Fischer, Axel; Groneberg, David A

    2003-01-01

    Sensory neuropeptides have been proposed to play a key role in the pathogenesis of a number of respiratory diseases such as asthma, chronic obstructive pulmonary disease or chronic cough. Next to prominent neuropeptides such as tachykinins or vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP) has long been suggested to participate in airway physiology and pathophysiology. CGRP is a 37 amino-acid peptide which is expressed by nerve fibers projecting to the airways and by pulmonary neuroendocrine cells. The most prominent effects of CGRP in the airways are vasodilatation and in a few instances bronchoconstriction. A further pulmonary effect of CGRP is the induction of eosinophil migration and the stimulation of beta-integrin-mediated T cell adhesion to fibronectin at the site of inflammation. By contrast, CGRP inhibits macrophage secretion and the capacity of macrophages to activate T-cells, indicating a potential anti-inflammatory effect. Due to the complex pulmonary effects of CGRP with bronchoconstriction and vasodilatation and diverse immunomodulatory actions, potential anti-asthma drugs based on this peptide have not been established so far. However, targeting the effects of CGRP may be of value for future strategies in nerve modulation.

  15. [Intestinal microbiota].

    PubMed

    Debré, Patrice; Le Gall, Jean-Yves

    2014-12-01

    The human body normally lives in symbiosis with a considerable microscopic environment present on all interfaces with the external environment; it hosts ten times more microbes (microbiota) that it has somatic or germ cells, representing a gene diversity (microbiome) 100-150 times higher than the human genome. These germs are located mainly in the gut, where they represent a mass of about one kilogram. The primary colonization of the gastrointestinal tract depends on the delivery route, the bacterial flora rewarding then depending on the environment, food hygiene, medical treatments. The intestinal microbiota plays an important role in the maturation of the immune system and in different physiological functions: digestion of polysaccharides, glycosaminoglycans and glycoproteins, vitamins biosynthesis, bile salt metabolism of some amino acids and xenobiotics. Quantitative and qualitative changes in the microbiota are observed in a wide range of diseases: obesity, colorectal cancer, liver cancer, inflammatory bowel disease, autoimmune diseases, allergies... pharmacobiotics aim to modify the intestinal microbiota in a therapeutic goal and this by various means: prebiotics, probiotics, antibiotics or fecal transplants. Intestinal flora also plays a direct role in the metabolism of certain drugs and the microbiota should be considered as a predictive parameter of response to some chemotherapies.

  16. Innervation of enteric mast cells by primary spinal afferents in guinea pig and human small intestine.

    PubMed

    Wang, Guo-Du; Wang, Xi-Yu; Liu, Sumei; Qu, Meihua; Xia, Yun; Needleman, Bradley J; Mikami, Dean J; Wood, Jackie D

    2014-10-01

    Mast cells express the substance P (SP) neurokinin 1 receptor and the calcitonin gene-related peptide (CGRP) receptor in guinea pig and human small intestine. Enzyme-linked immunoassay showed that activation of intramural afferents by antidromic electrical stimulation or by capsaicin released SP and CGRP from human and guinea pig intestinal segments. Electrical stimulation of the afferents evoked slow excitatory postsynaptic potentials (EPSPs) in the enteric nervous system. The slow EPSPs were mediated by tachykinin neurokinin 1 and CGRP receptors. Capsaicin evoked slow EPSP-like responses that were suppressed by antagonists for protease-activated receptor 2. Afferent stimulation evoked slow EPSP-like excitation that was suppressed by mast cell-stabilizing drugs. Histamine and mast cell protease II were released by 1) exposure to SP or CGRP, 2) capsaicin, 3) compound 48/80, 4) elevation of mast cell Ca²⁺ by ionophore A23187, and 5) antidromic electrical stimulation of afferents. The mast cell stabilizers cromolyn and doxantrazole suppressed release of protease II and histamine when evoked by SP, CGRP, capsaicin, A23187, electrical stimulation of afferents, or compound 48/80. Neural blockade by tetrodotoxin prevented mast cell protease II release in response to antidromic electrical stimulation of mesenteric afferents. The results support a hypothesis that afferent innervation of enteric mast cells releases histamine and mast cell protease II, both of which are known to act in a diffuse paracrine manner to influence the behavior of enteric nervous system neurons and to elevate the sensitivity of spinal afferent terminals.

  17. Innervation of enteric mast cells by primary spinal afferents in guinea pig and human small intestine

    PubMed Central

    Wang, Guo-Du; Wang, Xi-Yu; Liu, Sumei; Qu, Meihua; Xia, Yun; Needleman, Bradley J.; Mikami, Dean J.

    2014-01-01

    Mast cells express the substance P (SP) neurokinin 1 receptor and the calcitonin gene-related peptide (CGRP) receptor in guinea pig and human small intestine. Enzyme-linked immunoassay showed that activation of intramural afferents by antidromic electrical stimulation or by capsaicin released SP and CGRP from human and guinea pig intestinal segments. Electrical stimulation of the afferents evoked slow excitatory postsynaptic potentials (EPSPs) in the enteric nervous system. The slow EPSPs were mediated by tachykinin neurokinin 1 and CGRP receptors. Capsaicin evoked slow EPSP-like responses that were suppressed by antagonists for protease-activated receptor 2. Afferent stimulation evoked slow EPSP-like excitation that was suppressed by mast cell-stabilizing drugs. Histamine and mast cell protease II were released by 1) exposure to SP or CGRP, 2) capsaicin, 3) compound 48/80, 4) elevation of mast cell Ca2+ by ionophore A23187, and 5) antidromic electrical stimulation of afferents. The mast cell stabilizers cromolyn and doxantrazole suppressed release of protease II and histamine when evoked by SP, CGRP, capsaicin, A23187, electrical stimulation of afferents, or compound 48/80. Neural blockade by tetrodotoxin prevented mast cell protease II release in response to antidromic electrical stimulation of mesenteric afferents. The results support a hypothesis that afferent innervation of enteric mast cells releases histamine and mast cell protease II, both of which are known to act in a diffuse paracrine manner to influence the behavior of enteric nervous system neurons and to elevate the sensitivity of spinal afferent terminals. PMID:25147231

  18. Analysis of differentially expressed genes in response to bacterial stimulation in hemocytes of the carpet-shell clam Ruditapes decussatus: identification of new antimicrobial peptides.

    PubMed

    Gestal, Camino; Costa, Marímar; Figueras, Antonio; Novoa, Beatriz

    2007-12-30

    Suppression subtractive hybridization was used to identify differentially expressed genes in hemocytes from carpet-shell clam Ruditapes decussatus stimulated with a mixture of dead bacterial strains. Putative function could be assigned to 100 of the 253 sequenced cDNAs. Based on sequence homologies, 3.16% of the total identified genes were possibly related to immune functions. Clam myticin isoforms 1, 2 and 3, and clam mytilin, with similarity with myticins and mytilins previously reported on Mytilus galloprovincialis were identified and characterized for the first time in clams. The analysis of their expression levels by quantitative PCR showed that they were induced by bacterial challenge. The results obtained in this work could be the first step leading to the understanding of molecular mechanisms by which these economically important marine bivalves respond to pathogens.

  19. Stimulation of glucagon-like peptide-1 receptor through exendin-4 preserves myocardial performance and prevents cardiac remodeling in infarcted myocardium

    PubMed Central

    DeNicola, Megan; Du, Jianfeng; Wang, Zhengke; Yano, Naohiro; Zhang, Ling; Wang, Yigang; Qin, Gangjian; Zhuang, Shougang

    2014-01-01

    We have demonstrated that GLP-1 improved myocardial functional recovery in acute myocardial ischemic injury. However, whether stimulation of the GLP-1 receptor (GLP-1R) with exendin-4, a selective GLP-1R agonist, could initiate a protective effect in the heart remains to be determined. Mouse myocardial infarction (MI) was created by ligation of the left descending artery. After 48 h of MI, animals were divided into the following groups (n = 5–7/group): 1) sham (animals that underwent thoracotomy without ligation), 2) MI [animals that underwent MI and received a daily dose of intraperitoneal injection (ip) of saline]; and 3) MI + exendin-4 [infarcted mice that received injections of exendin-4 (0.1 mg/kg ip)]. Two weeks later, cardiac function was assessed by echocardiography and an isovolumetrically perfused heart. Compared with control MI hearts, stimulation of GLP-1R improved cardiac function, which was associated with attenuation of myocardial hypertrophy, the mitigation of interstitial fibrosis, and an increase in survival rate in post-MI hearts. Furthermore, H9c2 cardiomyoblasts were preconditioned with exendin-4 at a dose of 100 nmol/l and then subjected to hydrogen peroxide exposure at concentrations of 50 and 100 μmol/l. The exendin-4 treatment decreased lactate dehydrogenase leakage and increased cell survival. Notably, this event was also associated with the reduction of cleaved caspase-3 and caspase-9 and attenuation of reactive oxygen species production. Exendin-4 treatments improved mitochondrial respiration and suppressed the opening of mitochondrial permeability transition pore and protected mitochondria function. Our results indicate that GLP-1R serves as a novel approach to eliciting cardioprotection and mitigating oxidative stress-induced injury. PMID:25117407

  20. Large Gliadin Peptides Detected in the Pancreas of NOD and Healthy Mice following Oral Administration

    PubMed Central

    Sidenius, Ulrik; Heegaard, Niels H.

    2016-01-01

    Gluten promotes type 1 diabetes in nonobese diabetic (NOD) mice and likely also in humans. In NOD mice and in non-diabetes-prone mice, it induces inflammation in the pancreatic lymph nodes, suggesting that gluten can initiate inflammation locally. Further, gliadin fragments stimulate insulin secretion from beta cells directly. We hypothesized that gluten fragments may cross the intestinal barrier to be distributed to organs other than the gut. If present in pancreas, gliadin could interact directly with the immune system and the beta cells to initiate diabetes development. We orally and intravenously administered 33-mer and 19-mer gliadin peptide to NOD, BALB/c, and C57BL/6 mice and found that the peptides readily crossed the intestinal barrier in all strains. Several degradation products were found in the pancreas by mass spectroscopy. Notably, the exocrine pancreas incorporated large amounts of radioactive label shortly after administration of the peptides. The study demonstrates that, even in normal animals, large gliadin fragments can reach the pancreas. If applicable to humans, the increased gut permeability in prediabetes and type 1 diabetes patients could expose beta cells directly to gliadin fragments. Here they could initiate inflammation and induce beta cell stress and thus contribute to the development of type 1 diabetes. PMID:27795959

  1. Melanins from opioid peptides.

    PubMed

    Rosei, M A

    1996-12-01

    Opioid peptides and other Tyr-NH2-terminal peptides are substrates in vitro for mushroom and sepia tyrosine, giving rise to synthetic melanins retaining the peptide moiety (opiomelanins). The melanopeptides are characterized by a total solubility in hydrophylic solvents at neutral and basic pH. Opioid peptides (enkephalins, endorphins, and esorphins), if oxidized by tyrosinase in the presence of Dopa, are easily incorporated into Dopa-melanin, producing mixed-type pigments that can also be solubilized in hydrophylic solvents. Melanins derived from opioid peptides exhibit paramagnetism, as evidenced by an EPR spectrum identical to that of Dopa-melanin. However, the presence of the linked peptide chain is able to influence dramatically the electron transfer properties and the oxidizing behaviour of the melanopeptides, so that whereas Tyr-Gly-melanin appears to behave as Dopa-melanin, Enk-melanin does not exhibit any oxidizing activity. Opiomelanins are characterized by a peculiar UV-VIS spectrum; that is, by the presence of a distinct peak (330 nm) that disappears upon chemical treatment by acid hydrolysis. Opiomelanins are stable pigments at neutral and basic pH in the dark, whereas the addition of H2O2 leads to a 15% degradation. Under stimulated solar illumination, opiomelanins are more easily destroyed with respect to Dopa-melanin, with increasing degradation when exposed to increased hydrogen peroxide concentrations and more alkaline pH. Some speculations on the possible existence and role of opiomelanins have been outlined.

  2. Therapeutic Efficacy of a {sup 188}Re-Labeled {alpha}-Melanocyte-Stimulating Hormone Peptide Analog in Murine and Human Melanoma-Bearing Mouse Models

    SciTech Connect

    Miao, Yubin; Owen, Nellie K.; Fisher, Darrell R.; Hoffman, Timothy J.; Quinn, Thomas P.

    2005-01-01

    The purpose of this study was to examine the therapeutic efficacy of {sup 188}Re-(Arg{sup 11})CCMSH in the B16/F1 murine melanoma and TXM13 human melanoma bearing mouse models. Method: (Arg11)CCMSH was synthesized and labeled with {sup 188}Re to form {sup 188}Re-(Agr{sup 11})CCMSH. B16/F1 melanoma tumor bearing mice were administrated with 200 Ci, 600 Ci and 2x400 Ci of {sup 188}Re-(Arg{sup 11})CCMSH via the tail vein, respectively. TXM13 melanoma tumor hearing mice were separately injected with 600 Ci, 2x400 Ci and 1000 Ci of 100Re-(Arg{sup 11})CCMSH through the tail vein. Two groups of 10 mice bearing either B16/F1 or TXM13 tumors were injected with saline as untreated controls. Results: In contrast to the untreated control group, {sup 188}Re(Arg11)CCMSH yielded rapid and lasting therapeutic effects in the treatment groups with either B16/F1 or TXM13 tumors. The tumor growth rate was reduced and the survival rate was prolonged in the treatment groups. Treatment with 2x400 Ci of {sup 188}Re-Arg{sup 11}CCMSH significantly extended the mean life of B16/F1 tumor mice (p<0.05), while the mean life of TXm13 tumor mice was significantly prolonged after treatment with 600 Ci and 1000 Ci doses of {sup 188}Re-(Arg{sup 11})CCMSH (p<0.05 High-dose {sup 188}Re-(Arg{sup 11}))CCMSH produced no observed normal-tissue toxicity. Conclusions: The therapy study results revealed that {sup 188}Re-Arg11 CCMSH yielded significant therapeutic effects in both B16/F1 murine melanoma and TXM13 human melanoma bearing mouse models. {sup 188}Re-(Arg{sup 11})CCMSH appears to be a promising radiolabeled peptide for targeted radionuclide therapy of melanoma.

  3. Replacement of the Lys linker with an Arg linker resulting in improved melanoma uptake and reduced renal uptake of Tc-99m-labeled Arg-Gly-Asp-conjugated alpha-melanocyte stimulating hormone hybrid peptide.

    PubMed

    Yang, Jianquan; Guo, Haixun; Padilla, R Steve; Berwick, Marianne; Miao, Yubin

    2010-09-15

    The purpose of this study was to reduce the non-specific renal uptake of Arg-Gly-Asp (RGD)-conjugated alpha-melanocyte stimulating hormone (alpha-MSH) hybrid peptide through structural modification or L-lysine co-injection. The RGD motif {cyclic(Arg-Gly-Asp-DTyr-Asp)} was coupled to [Cys(3,4,10), D-Phe7, Arg11] alpha-MSH3-13 {(Arg11)CCMSH} through the Arg linker (substituting the Lys linker) to generate a novel RGD-Arg-(Arg11)CCMSH hybrid peptide. The melanoma targeting and pharmacokinetic properties of 99mTc-RGD-Arg-(Arg11)CCMSH were determined in B16/F1 melanoma-bearing C57 mice. The effect of L-lysine co-injection on the renal uptake was determined through the co-injection of L-lysine with 99mTc-RGD-Arg-(Arg11)CCMSH or 99mTc-RGD-Lys-(Arg11)CCMSH. Replacement of the Lys linker with an Arg linker exhibited a profound effect in reducing the non-specific renal uptake of 99mTc-RGD-Arg-(Arg11)CCMSH, as well as increasing the tumor uptake of 99mTc-RGD-Arg-(Arg11)CCMSH compared to 99mTc-RGD-Lys-(Arg11)CCMSH. 99mTc-RGD-Arg-(Arg11)CCMSH exhibited high tumor uptake (21.41+/-3.74% ID/g at 2 h post-injection) and prolonged tumor retention (6.81+/-3.71% ID/g at 24 h post-injection) in B16/F1 melanoma-bearing mice. The renal uptake values of 99mTc-RGD-Arg-(Arg11)CCMSH were 40.14-64.08% of those of 99mTc-RGD-Lys-(Arg11)CCMSH (p<0.05) at 0.5, 2, 4 and 24 h post-injection. Co-injection of L-lysine was effective in decreasing the renal uptakes of 99mTc-RGD-Arg-(Arg11)CCMSH by 27.7% and 99mTc-RGD-Lys-(Arg11)CCMSH by 52.1% at 2 h post-injection. Substitution of the Lys linker with an Arg linker dramatically improved the melanoma uptake and reduced the renal uptake of 99mTc-RGD-Arg-(Arg11)CCMSH, warranting the further evaluation of 188Re-labeled RGD-Arg-(Arg11)CCMSH as a novel MC1 receptor-targeting therapeutic peptide for melanoma treatment in the future.

  4. The influence of protein fractions from bovine colostrum digested in vivo and in vitro on human intestinal epithelial cell proliferation.

    PubMed

    Morgan, Alison J; Riley, Lisa G; Sheehy, Paul A; Wynn, Peter C

    2014-02-01

    Colostrum consists of a number of biologically active proteins and peptides that influence physiological function and development of a neonate. The present study investigated the biological activity of peptides released from first day bovine colostrum through in vitro and in vivo enzymatic digestion. This was assessed for proliferative activity using a human intestinal epithelial cell line, T84. Digestion of the protein fraction of bovine colostrum in vitro was conducted with the enzymes pepsin, chymosin and trypsin. Pepsin and chymosin digests yielded protein fractions with proliferative activity similar to that observed with undigested colostrum and the positive control foetal calf serum (FCS). In contrast trypsin digestion significantly (P<0·05) decreased colostral proliferative activity when co-cultured with cells when compared with undigested colostrum. The proliferative activity of undigested colostrum protein and abomasal whey protein digesta significantly increased (P<0·05) epithelial cell proliferation in comparison to a synthetic peptide mix. Bovine colostrum protein digested in vivo was collected from different regions of the gastrointestinal tract (GIT) in newborn calves fed either once (n=3 calves) or three times at 12-h intervals (n=3 calves). Digesta collected from the distal duodenum, jejunum and colon of calves fed once, significantly (P<0·05) stimulated cell proliferation in comparison with comparable samples collected from calves fed multiple times. These peptide enriched fractions are likely to yield candidate peptides with potential application for gastrointestinal repair in mammalian species.

  5. Human milk hyaluronan enhances innate defense of the intestinal epithelium.

    PubMed

    Hill, David R; Rho, Hyunjin K; Kessler, Sean P; Amin, Ripal; Homer, Craig R; McDonald, Christine; Cowman, Mary K; de la Motte, Carol A

    2013-10-04

    Breast-feeding is associated with enhanced protection from gastrointestinal disease in infants, mediated in part by an array of bioactive glycan components in milk that act through molecular mechanisms to inhibit enteric pathogen infection. Human milk contains hyaluronan (HA), a glycosaminoglycan polymer found in virtually all mammalian tissues. We have shown that synthetic HA of a specific size range promotes expression of antimicrobial peptides in intestinal epithelium. We hypothesize that hyaluronan from human milk also enhances innate antimicrobial defense. Here we define the concentration of HA in human milk during the first 6 months postpartum. Importantly, HA isolated from milk has a biological function. Treatment of HT-29 colonic epithelial cells with human milk HA at physiologic concentrations results in time- and dose-dependent induction of the antimicrobial peptide human β-defensin 2 and is abrogated by digestion of milk HA with a specific hyaluronidase. Milk HA induction of human β-defensin 2 expression is also reduced in the presence of a CD44-blocking antibody and is associated with a specific increase in ERK1/2 phosphorylation, suggesting a role for the HA receptor CD44. Furthermore, oral administration of human milk-derived HA to adult, wild-type mice results in induction of the murine Hβ D2 ortholog in intestinal mucosa and is dependent upon both TLR4 and CD44 in vivo. Finally, treatment of cultured colonic epithelial cells with human milk HA enhances resistance to infection by the enteric pathogen Salmonella typhimurium. Together, our observations suggest that maternally provided HA stimulates protective antimicrobial defense in the newborn.

  6. Potent and selective peptide agonists of alpha-melanocyte stimulating hormone (alphaMSH) action at human melanocortin receptor 5; their synthesis and biological evaluation in vitro.

    PubMed

    Bednarek, Maria A; MacNeil, Tanya; Tang, Rui; Fong, Tung M; Angeles Cabello, M; Maroto, Marta; Teran, Ana

    2007-05-01

    Melanocortin receptors (MC1-5R) and their endogenous ligands (melanocyte-stimulating hormones and adrenocorticotropic hormone) are involved in many physiological processes in humans. Of those receptors, the actions of MC5R are the least understood despite its broad presence in the numerous peripheral tissues and brain. In this study, we describe synthesis and pharmacological properties in vitro (receptor-binding affinity and agonist activity) of several cyclic analogs of alphaMSH which are potent agonists at hMC5R (EC(50) below 1 nM) and of enhanced receptor subtype selectivity (more than 2000-fold versus hMC1b,3R and about 70- to 200-fold versus hMC4R). These compounds are analogs of Ac-Nle(4)-cyclo[Asp(5)-His(6)-D-Nal(2')(7)-Pip(8)-Trp(9)-Lys(10)]-NH(2) (Pip: pipecolic acid) in which His(6) has been replaced with sterically hindered amino acids. They may be useful tools in the elucidation of the MC5R role in skin disorders and in immunomodulatory and in anti-inflammatory actions of alphaMSH.

  7. The non-peptide neurokinin-1 antagonist, RPR 100893, decreases c-fos expression in trigeminal nucleus caudalis following noxious chemical meningeal stimulation.

    PubMed

    Cutrer, F M; Moussaoui, S; Garret, C; Moskowitz, M A

    1995-02-01

    The effect of RPR 100893, a selective and specific neurokinin-1 antagonist, or its enantiomer RPR 103253 was examined on c-fos antigen expression in brain stem and upper cervical cord 2 h after intracisternal capsaicin injection (30.5 micrograms/ml) in pentobarbital-anesthetized Hartley guinea-pigs. Positive cells were counted at three levels corresponding to obex, -2.25 mm and -6.75 mm in 18 sections (50 microns). Immunoreactivity was strongly expressed within laminae I and IIo of trigeminal nucleus caudalis, area postrema and the leptomeninges. Moderate labeling was present in the nucleus of the solitary tract and the medullary lateral reticular nucleus, whereas few positive cells were found in the ventral portion of the medullary reticular nucleus and Rexed laminae III-V and X. The distribution of labeled cells was consistent with previously reported results following subarachnoid placement of the noxious agents, blood or carrageenin. Pretreatment with RPR 100893 (1, 10 and 100 micrograms/kg, i.v.) but not its enantiomer (100 micrograms/kg, i.v.) 30 min prior to capsaicin injection significantly reduced the number of positive cells in the trigeminal nucleus caudalis (P < 0.01) in a dose-dependent manner, but not within area postrema or nucleus of the solitary tract. These results indicate that (i) the instillation of capsaicin into the subarachnoid space is an effective stimulus for the induction of c-fos antigen within trigeminal nucleus caudalis, presumably through activation of trigeminovascular afferents, and (ii) the neurokinin-1 antagonist RPR 100893 reduces the number of positive cells selectively within this nucleus. The findings are significant because drugs which alleviate vascular headaches decrease the number of c-fos-positive cells within trigeminal nucleus caudalis following noxious meningeal stimulation. Hence, strategies aimed at blocking the neurokinin-1 receptor may be useful for treating migraine and cluster headache.

  8. Ingestion of oats and barley in patients with celiac disease mobilizes cross-reactive T cells activated by avenin peptides and immuno-dominant hordein peptides.

    PubMed

    Hardy, Melinda Y; Tye-Din, Jason A; Stewart, Jessica A; Schmitz, Frederike; Dudek, Nadine L; Hanchapola, Iresha; Purcell, Anthony W; Anderson, Robert P

    2015-01-01

    Celiac disease (CD) is a common CD4(+) T cell mediated enteropathy driven by gluten in wheat, rye, and barley. Whilst clinical feeding studies generally support the safety of oats ingestion in CD, the avenin protein from oats can stimulate intestinal gluten-reactive T cells isolated from some CD patients in vitro. Our objective was to establish whether ingestion of oats or other grains toxic in CD stimulate an avenin-specific T cell response in vivo. We fed participants a meal of oats (100 g/day over 3 days) to measure the in vivo polyclonal avenin-specific T cell responses to peptides contained within comprehensive avenin peptide libraries in 73 HLA-DQ2.5(+) CD patients. Grain cross-reactivity was investigated using oral challenge with wheat, barley, and rye. Avenin-specific responses were observed in 6/73 HLA-DQ2.5(+) CD patients (8%), against four closely related peptides. Oral barley challenge efficiently induced cross-reactive avenin/hordein-specific T cells in most CD patients, whereas wheat or rye challenge did not. In vitro, immunogenic avenin peptides were susceptible to digestive endopeptidases and showed weak HLA-DQ2.5 binding stability. Our findings indicate that CD patients possess T cells capable of responding to immuno-dominant hordein epitopes and homologous avenin peptides ex vivo, but the frequency and consistency of these T cells in blood is substantially higher after oral challenge with barley compared to oats. The low rates of T cell activation after a substantial oats challenge (100 g/d) suggests that doses of oats commonly consumed are insufficient to cause clinical relapse, and supports the safety of oats demonstrated in long-term feeding studies.

  9. A 21-amino acid peptide from the cysteine cluster II of the family D DNA polymerase from Pyrococcus horikoshii stimulates its nuclease activity which is Mre11-like and prefers manganese ion as the cofactor.

    PubMed

    Shen, Yulong; Tang, Xiao-Feng; Yokoyama, Hideshi; Matsui, Eriko; Matsui, Ikuo

    2004-01-01

    Family D DNA polymerase (PolD) is a new type of DNA polymerase possessing polymerization and 3'-5' exonuclease activities. Here we report the characterization of the nuclease activity of PolD from Pyrococcus horikoshii. By site-directed mutagenesis, we verified that the putative Mre11-like nuclease domain in the small subunit (DP1), predicted according to computer analysis and structure inference reported previously, is the catalytic domain. We show that D363, H365 and H454 are the essential residues, while D407, N453, H500, H563 and H565 are critical residues for the activity. We provide experimental evidence demonstrating that manganese, rather than magnesium, is the preferable metal ion for the nuclease activity of PolD. We also show that DP1 alone is insufficient to perform full catalysis, which additionally requires the formation of the PolD complex and manganese ion. We found that a 21 amino acid, subunit-interacting peptide of the sequence from cysteine cluster II of the large subunit (DP2) stimulates the exonuclease activity of DP1 and the internal deletion mutants of PolD lacking the 21-aa sequence. This indicates that the putative zinc finger motif of the cysteine cluster II is deeply involved in the nucleolytic catalysis.

  10. Identification of multifunctional peptides from human milk.

    PubMed

    Mandal, Santi M; Bharti, Rashmi; Porto, William F; Gauri, Samiran S; Mandal, Mahitosh; Franco, Octavio L; Ghosh, Ananta K

    2014-06-01

    Pharmaceutical industries have renewed interest in screening multifunctional bioactive peptides as a marketable product in health care applications. In this context, several animal and plant peptides with potential bioactivity have been reported. Milk proteins and peptides have received much attention as a source of health-enhancing components to be incorporated into nutraceuticals and functional foods. By using this source, 24 peptides have been fractionated and purified from human milk using RP-HPLC. Multifunctional roles including antimicrobial, antioxidant and growth stimulating activity have been evaluated in all 24 fractions. Nevertheless, only four fractions show multiple combined activities among them. Using a proteomic approach, two of these four peptides have been identified as lactoferrin derived peptide and kappa casein short chain peptide. Lactoferrin derived peptide (f8) is arginine-rich and kappa casein derived (f12) peptide is proline-rich. Both peptides (f8 and f12) showed antimicrobial activities against both Gram-positive and Gram-negative bacteria. Fraction 8 (f8) exhibits growth stimulating activity in 3T3 cell line and f12 shows higher free radical scavenging activity in comparison to other fractions. Finally, both peptides were in silico evaluated and some insights into their mechanism of action were provided. Thus, results indicate that these identified peptides have multiple biological activities which are valuable for the quick development of the neonate and may be considered as potential biotechnological products for nutraceutical industry.

  11. Intestinal capillariasis.

    PubMed Central

    Cross, J H

    1992-01-01

    Intestinal capillariasis caused by Capillaria philippinensis appeared first in the Philippines and subsequently in Thailand, Japan, Iran, Egypt, and Taiwan, but most infections occur in the Philippines and Thailand. As established experimentally, the life cycle involves freshwater fish as intermediate hosts and fish-eating birds as definitive hosts. Embryonated eggs from feces fed to fish hatch and grow as larvae in the fish intestines. Infective larvae fed to monkeys, Mongolian gerbils, and fish-eating birds develop into adults. Larvae become adults in 10 to 11 days, and the first-generation females produce larvae. These larvae develop into males and egg-producing female worms. Eggs pass with the feces, reach water, embryonate, and infect fish. Autoinfection is part of the life cycle and leads to hyperinfection. Humans acquire the infection by eating small freshwater fish raw. The parasite multiplies, and symptoms of diarrhea, borborygmus, abdominal pain, and edema develop. Chronic infections lead to malabsorption and hence to protein and electrolyte loss, and death results from irreversible effects of the infection. Treatment consists of electrolyte replacement and administration of an antidiarrheal agent and mebendazole or albendazole. Capillariasis philippinensis is considered a zoonotic disease of migratory fish-eating birds. The eggs are disseminated along flyways and infect the fish, and when fish are eaten raw, the disease develops. Images PMID:1576584

  12. Intestinal capillariasis.

    PubMed

    Cross, J H

    1992-04-01

    Intestinal capillariasis caused by Capillaria philippinensis appeared first in the Philippines and subsequently in Thailand, Japan, Iran, Egypt, and Taiwan, but most infections occur in the Philippines and Thailand. As established experimentally, the life cycle involves freshwater fish as intermediate hosts and fish-eating birds as definitive hosts. Embryonated eggs from feces fed to fish hatch and grow as larvae in the fish intestines. Infective larvae fed to monkeys, Mongolian gerbils, and fish-eating birds develop into adults. Larvae become adults in 10 to 11 days, and the first-generation females produce larvae. These larvae develop into males and egg-producing female worms. Eggs pass with the feces, reach water, embryonate, and infect fish. Autoinfection is part of the life cycle and leads to hyperinfection. Humans acquire the infection by eating small freshwater fish raw. The parasite multiplies, and symptoms of diarrhea, borborygmus, abdominal pain, and edema develop. Chronic infections lead to malabsorption and hence to protein and electrolyte loss, and death results from irreversible effects of the infection. Treatment consists of electrolyte replacement and administration of an antidiarrheal agent and mebendazole or albendazole. Capillariasis philippinensis is considered a zoonotic disease of migratory fish-eating birds. The eggs are disseminated along flyways and infect the fish, and when fish are eaten raw, the disease develops.

  13. Calcium glycerophosphate preserves transepithelial integrity in the Caco-2 model of intestinal transport

    PubMed Central

    Datta, Palika; Weis, Margaret T

    2015-01-01

    AIM: To assess the direct effects of ischemia on intestinal epithelial integrity. Furthermore, clinical efforts at mitigating the effect of hypoperfusion on gut permeability have focused on restoring gut vascular function. METHODS: We report that, in the Caco-2 cell model of transepithelial transport, calcium glycerophosphate (CGP), an inhibitor of intestinal alkaline phosphatase F3, has a significant effect to preserve transepithelial electrical resistance (TEER) and to attenuate increases in mannitol flux rates during hypoxia or cytokine stimulation. RESULTS: The effect was observable even at concentrations as low as 1 μmol/L. As celiac disease is also marked by a loss of gut epithelial integrity, the effect of CGP to attenuate the effect of the α-gliadin peptide 31-55 was also examined. In this instance, CGP exerted little effect of preservation of TEER, but significantly attenuated peptide induced increase in mannitol flux. CONCLUSION: It appears that CGP treatment might synergize with other therapies to preserve gut epithelial integrity. PMID:26290632

  14. Preparation and characterization of coacervate microcapsules for the delivery of antimicrobial oyster peptides.

    PubMed

    Zhang, Li; Liu, Yezhou; Wu, Zhongchen; Chen, Haixu

    2009-03-01

    Oyster peptides-loaded alginate/chitosan/starch microcapsules were prepared using external gelation method and internal emulsion gelation method. The solution of oyster peptides complexes was encapsulated into the microcapsules, which endowed the microcapsules with intestine passive targeting properties. The swelling behavior, encapsulation efficiency, and release behavior of oyster peptides from the microcapsules at different pH values were investigated. The microcapsules exhibited sustained release of the peptides in intestinal medium, and the release rate could be regulated by the pH value: in simulated gastric fluid, the release rate was greatly decreased, and in simulated body fluid and intestinal fluid, the microcapsules exhibited a sustained release in 24 h with different release rates. The microspheres were characterized by Fourier transform infrared. The results suggested that the alginate/chitosan/starch microcapsules could be a suitable copolymeric carrier system for intestinal protein or peptides delivery in the intestine.

  15. RANTES (CCL5) reduces glucose-dependent secretion of glucagon-like peptides 1 and 2 and impairs glucose-induced insulin secretion in mice.

    PubMed

    Pais, Ramona; Zietek, Tamara; Hauner, Hans; Daniel, Hannelore; Skurk, Thomas

    2014-08-01

    Type 2 diabetes is associated with elevated circulating levels of the chemokine RANTES and with decreased plasma levels of the incretin hormone glucagon-like peptide 1 (GLP-1). GLP-1 is a peptide secreted from intestinal L-cells upon nutrient ingestion. It enhances insulin secretion from pancreatic β-cells and protects from β-cell loss but also promotes satiety and weight loss. In search of chemokines that may reduce GLP-1 secretion we identified RANTES and show that it reduces glucose-stimulated GLP-1 secretion in the human enteroendocrine cell line NCI-H716, blocked by the antagonist Met-RANTES, and in vivo in mice. RANTES exposure to mouse intestinal tissues lowers transport function of the intestinal glucose transporter SGLT1, and administration in mice reduces plasma GLP-1 and GLP-2 levels after an oral glucose load and thereby impairs insulin secretion. These data show that RANTES is involved in altered secretion of glucagon-like peptide hormones most probably acting through SGLT1, and our study identifies the RANTES-receptor CCR1 as a potential target in diabetes therapy.

  16. Intestinally-targeted TGR5 agonists equipped with quaternary ammonium have an improved hypoglycemic effect and reduced gallbladder filling effect

    PubMed Central

    Cao, Hua; Chen, Zhi-Xiang; Wang, Kai; Ning, Meng-Meng; Zou, Qing-An; Feng, Ying; Ye, Yang-Liang; Leng, Ying; Shen, Jian-Hua

    2016-01-01

    TGR5 activation of enteroendocrine cells increases glucagon-like peptide 1 (GLP-1) release, which maintains glycemic homeostasis. However, TGR5 activation in the gallbladder and heart is associated with severe side effects. Therefore, intestinally-targeted TGR5 agonists were suggested as potential hypoglycemic agents with minimal side effects. However, until now no such compounds with robust glucose-lowering effects were reported, especially in diabetic animal models. Herein, we identify a TGR5 agonist, 26a, which was proven to be intestinally-targeted through pharmacokinetic studies. 26a was used as a tool drug to verify the intestinally-targeted strategy. 26a displayed a robust and long-lasting hypoglycemic effect in ob/ob mice (once a day dosing (QD) and 18-day treatment) owing to sustained stimulation of GLP-1 secretion, which suggested that robust hypoglycemic effect could be achieved with activation of TGR5 in intestine alone. However, the gallbladder filling effect of 26a was rather complicated. Although the gallbladder filling effect of 26a was decreased in mice after once a day dosing, this side effect was still not eliminated. To solve the problem above, several research strategies were raised for further optimization. PMID:27339735

  17. Intestinal mast cells and eosinophils in relation to Strongyloides ratti adult expulsion from the small and large intestines of rats.

    PubMed

    Shintoku, Y; Kadosaka, T; Kimura, E; Takagi, H; Kondo, S; Itoh, M

    2013-04-01

    Mucosal mast cells (MMC) play a crucial role in the expulsion of Strongyloides ratti adults from the small intestine of mice. We reported the large intestinal parasitism of S. ratti in rats, and there has been no report on MMC in the large intestine of the natural host. We studied kinetics of MMC, together with eosinophils, in the upper and lower small intestines, caecum and colon of infected rats. Two distinct phases of mastocytosis were revealed: one in the upper small intestine triggered by stimulation of 'ordinary' adults, and the other in the colon stimulated by 'immune-resistant' adults that started parasitizing the colon around 19 days post-infection. In all 4 intestinal sites, the MMC peaks were observed 5-7 days after the number of adult worms became the maximum and the height of MMC peaks appeared to be dependent on the number of parasitic adults, suggesting an important role played by worms themselves in the MMC buildup.

  18. Somatostatin peptides inhibit basolateral potassium channels in human colonic crypts.

    PubMed

    Sandle, G I; Warhurst, G; Butterfield, I; Higgs, N B; Lomax, R B

    1999-11-01

    Somatostatin is a powerful inhibitor of intestinal Cl(-) secretion. We used patch-clamp recording techniques to investigate the effects of somatostatin on low-conductance (23-pS) K(+) channels in the basolateral membrane of human colonic crypts, which are an important component of the Cl(-) secretory process. Somatostatin (2 microM) elicited a >80% decrease in "spontaneous" K(+) channel activity in cell-attached patches in nonstimulated crypts (50% inhibition = approximately 8 min), which was voltage-independent and was prevented by pretreating crypts for 18 h with pertussis toxin (200 ng/ml), implicating a G protein-dependent mechanism. In crypts stimulated with 100-200 microM dibutyryl cAMP, 2 microM somatostatin and its synthetic analog octreotide (2 microM) both produced similar degrees of K(+) channel inhibition to that seen in nonstimulated crypts, which was also present under low-Cl(-) (5 mM) conditions. In addition, 2 microM somatostatin abolished the increase in K(+) channel activity stimulated by 2 microM thapsigargin but had no effect on the thapsigargin-stimulated rise in intracellular Ca(2+). These results indicate that somatostatin peptides inhibit 23-pS basolateral K(+) channels in human colonic crypt cells via a G protein-dependent mechanism, which may result in loss of the channel's inherent Ca(2+) sensitivity.

  19. [Short bowel syndrome and intestinal failure - new developments].

    PubMed

    Lamprecht, Georg

    2015-12-01

    Intestinal failure is characterized by intestinal water and electrolyte losses as well as malabsorption of macronutrients. It often requires individually composed parenteral support (so call compounding). Teduglutide, a DPP-IV resistant GLP2 analogue, is available a pharmacologic treatment, which stimulates intestinal absorption and can facilitate infusion free days. Catheter infections are the most common complication of home parenteral support. The incidence can be minimized using Taurolidin as a catheter block solution.

  20. Intestinal protozoa.

    PubMed

    Juckett, G

    1996-06-01

    Giardia is the best known cause of protozoal gastrointestinal disease in North America, producing significant but not life-threatening gastrointestinal distress and diarrhea. Although diagnosis of giardiasis may be challenging, treatment is usually successful. Entamoeba histolytica poses a rarer but far more difficult clinical challenge. Dysentery caused by E. histolytica may be the most feared intestinal protozoal infection, although Cryptosporidium parvum, Balantidium coli, Isospora belli, Sarcocystis species and other newly described protozoa also may cause diarrhea in healthy individuals and may result in intractable, life-threatening illness in patients with acquired immunodeficiency syndrome or other immunosuppressive diseases. Certain protozoa once considered relatively unimportant, such as Cryptosporidium, are now recognized as significant causes of morbidity even in the United States, since transmission readily occurs through contaminated water.

  1. The Tripeptide KdPT Protects from Intestinal Inflammation and Maintains Intestinal Barrier Function

    PubMed Central

    Bettenworth, Dominik; Buyse, Marion; Böhm, Markus; Mennigen, Rudolf; Czorniak, Isabel; Kannengiesser, Klaus; Brzoska, Thomas; Luger, Thomas A.; Kucharzik, Torsten; Domschke, Wolfram; Maaser, Christian; Lügering, Andreas

    2011-01-01

    Treatment options for inflammatory bowel disease (IBD) are incompletely helpful, and surgery is often needed. One promising class of future therapeutic agents for IBD is melanocortin-related peptides, which exhibit potent immunomodulatory effects. We investigated KdPT, a tripeptide derivative of the C-terminus of α–melanocyte-stimulating hormone, as an anti-inflammatory small molecule in vivo and in vitro. Intestinal inflammation was studied after oral administration of dextran sodium sulfate and in IL-10 gene–deficient mice. The effects of KdPT on key colonic epithelial cell functions were studied in vitro and in vivo by evaluating proliferation, wound healing, transepithelial resistance, and expression of tight junction proteins. Melanin assays were performed to determine the melanotropic effects of KdPT. KdPT-treated animals showed markedly reduced severity of inflammation in both colitis models. In colonic epithelial cells, KdPT increased proliferation, accelerated closure of wounds, and improved transepithelial electrical resistance after stimulation with interferon-γ/tumor necrosis factor-α. Moreover, treatment with KdPT also prevented the loss of tight junction protein expression and improved barrier function in vivo. KdPT acted independently of IL-1 receptor type I in vivo and did not affect melanogenesis in vitro. KdPT is capable of attenuating the course of experimental colitis in different models and maintains epithelial cell function. Furthermore, KdPT does not induce pigmentation, emphasizing the potential of this small molecule for the future treatment of IBD. PMID:21741932

  2. Peptide Seems to Boost Human Memory.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1981

    1981-01-01

    This article discusses recent studies which have shown that the peptide hormone vasopressin apparently can stimulate memory and learning in healthy human volunteers and in certain mentally disturbed patients. (ECO)

  3. Pivotal roles of alpha-melanocyte-stimulating hormone and the melanocortin 4 receptor in leptin stimulation of prolactin secretion in rats.

    PubMed

    Watanobe, Hajime; Schiöth, Helgi B; Izumi, Junkichi

    2003-04-01

    Leptin, the obese gene product, was reported to stimulate prolactin (PRL) secretion, but the neuroendocrine mechanism underlying this hormonal response is largely unknown. Thus, in this study we examined the involvement of several important PRL regulators in the leptin-induced PRL secretion in male rats. Compared with the values in normally fed rats, food deprivation for 3 days significantly decreased both PRL and leptin levels in the plasma. These changes were reverted to normal by a 3-day constant infusion of 75 microg/kg/day of leptin to the fasted rats, while 225 microg/kg/day of leptin further elevated both PRL and leptin levels. These four groups of animals were used for the following experiments. Results of dopamine and serotonin turnover studies in the brain and the pituitary indicated that neither of these biogenic amines plays a primary role in mediating leptin's effects on PRL. Repeated intracerebroventricular injections over 72 h of neutralizing antibodies against vasoactive intestinal peptide, PRL-releasing peptide, or beta-endorphin, did not significantly suppress the leptin actions. However, both the blockade of the melanocortin (MC) 4 receptor (R) and the immunoquenching of brain alpha-melanocyte-stimulating hormone (alpha-MSH) completely abolished the leptin-induced PRL release, and the stimulation of the MC4-R, but not the MC3-R, significantly elevated PRL levels in the fasted rats. These results suggest that alpha-MSH, a cleaved peptide from pro-opiomelanocortin of which synthesis is stimulated by leptin, may be the pivotal neuropeptide in the brain mediating the leptin's stimulatory influence on PRL secretion. It was also suggested that the MC4-R may be the primary subtype of the MC-Rs mediating this action of alpha-MSH.

  4. Stability of peptide drugs in the colon.

    PubMed

    Wang, Jie; Yadav, Vipul; Smart, Alice L; Tajiri, Shinichiro; Basit, Abdul W

    2015-10-12

    This study was the first to investigate the colonic stability of 17 peptide molecules (insulin, calcitonin, glucagon, secretin, somatostatin, desmopressin, oxytocin, Arg-vasopressin, octreotide, ciclosporin, leuprolide, nafarelin, buserelin, histrelin, [D-Ser(4)]-gonadorelin, deslorelin, and goserelin) in a model of the large intestine using mixed human faecal bacteria. Of these, the larger peptides - insulin, calcitonin, somatostatin, glucagon and secretin - were metabolized rapidly, with complete degradation observed within 5 min. In contrast, a number of the smaller peptides - Arg-vasopressin, desmopressin, oxytocin, gonadorelin, goserelin, buserelin, leuprolide, nafarelin and deslorelin - degraded more slowly, while octreotide, histrelin and ciclosporin were seen to be more stable as compared to the other small peptides under the same conditions. Peptide degradation rate was directly correlated to peptide lipophilicity (logP); those peptides with a higher logP were more stable in the colonic model (R(2)=0.94). In the absence of human faecal bacteria, all peptides were stable. This study highlights the impact of the colonic environment - in particular, the gut microbiota - on the metabolism of peptide drugs, and identifies potential peptide candidates for drug delivery to the colon.

  5. [Intestinal microbiota].

    PubMed

    Perez, Horacio Joaquín; Menezes, Maria Elisabeth; d'Acâmpora, Armando José

    2014-01-01

    There is accumulative evidence on the multiple functions of the intestinal microflora in relation to the homeostasis of the host. At first considered as a simple mutualism, today this relationship proves to be essential to the health and to pathologic processes, particularly metabolic (eg, obesity) and gastrointestinal (eg, inflammatory bowel disease and functional disorders). The first studies were conducted on the microbiota from fecal material cultured anaerobically. With the advent of molecular biology, it has become possible to determine qualitative and quantitatively the dominant, subdominant and transients species. In recent years, there were advances in the understanding of the relationship betwen the microbiota and the host, as well as among the microorganisms in their respective niches. These advances result from translational integration of microbiology with specialities such as molecular biology, cell phisiology, immunology and ecology. There are few studies on the spatial distribution of the microflora in the gut. Unravelling the topography of the microflora in mammals is a way to validate new animal models for the study of microflora.

  6. Extra-intestinal calcium handling contributes to normal serum calcium levels when intestinal calcium absorption is suboptimal.

    PubMed

    Lieben, Liesbet; Verlinden, Lieve; Masuyama, Ritsuko; Torrekens, Sophie; Moermans, Karen; Schoonjans, Luc; Carmeliet, Peter; Carmeliet, Geert

    2015-12-01

    The active form of vitamin D, 1,25(OH)2D, is a crucial regulator of calcium homeostasis, especially through stimulation of intestinal calcium transport. Lack of intestinal vitamin D receptor (VDR) signaling does however not result in hypocalcemia, because the increased 1,25(OH)2D levels stimulate calcium handling in extra-intestinal tissues. Systemic VDR deficiency, on the other hand, results in hypocalcemia because calcium handling is impaired not only in the intestine, but also in kidney and bone. It remains however unclear whether low intestinal VDR activity, as observed during aging, is sufficient for intestinal calcium transport and for mineral and bone homeostasis. To this end, we generated mice that expressed the Vdr exclusively in the gut, but at reduced levels. We found that ~15% of intestinal VDR expression greatly prevented the Vdr null phenotype in young-adult mice, including the severe hypocalcemia. Serum calcium levels were, however, in the low-normal range, which may be due to the suboptimal intestinal calcium absorption, renal calcium loss, insufficient increase in bone resorption and normal calcium incorporation in the bone matrix. In conclusion, our results indicate that low intestinal VDR levels improve intestinal calcium absorption compared to Vdr null mice, but also show that 1,25(OH)2D-mediated fine-tuning of renal calcium reabsorption and bone mineralization and resorption is required to maintain fully normal serum calcium levels.

  7. Noninflammatory Gluten Peptide Analogs as Biomarkers for Celiac Sprue

    PubMed Central

    Bethune, Michael T.; Crespo-Bosque, Mónica; Bergseng, Elin; Mazumdar, Kaushiki; Doyle, Lara; Sestak, Karol; Sollid, Ludvig M.; Khosla, Chaitan

    2013-01-01

    SUMMARY New tools are needed for managing celiac sprue, a lifelong immune disease of the small intestine. Ongoing drug trials are also prompting a search for noninvasive biomarkers of gluten-induced intestinal change. We have synthesized and characterized noninflammatory gluten peptide analogs in which key Gln residues are replaced by Asn or His. Like their proinflammatory counterparts, these biomarkers are resistant to gastrointestinal proteases, susceptible to glutenases, and permeable across enterocyte barriers. Unlike gluten peptides, however, they are not appreciably recognized by transglutaminase, HLA-DQ2, or disease-specific T cells. In vitro and animal studies show that the biomarkers can detect intestinal permeability changes as well as glutenase-catalyzed gastric detoxification of gluten. Accordingly, controlled clinical studies are warranted to evaluate the use of these peptides as probes for abnormal intestinal permeability in celiac patients and for glutenase efficacy in clinical trials and practice. PMID:19716477

  8. REVIEW: Role of cyclic AMP signaling in the production and function of the incretin hormone glucagon-like peptide-1

    NASA Astrophysics Data System (ADS)

    Yu, Zhiwen; Jin, Tianru

    2008-01-01

    Pancreatic cells express the proglucagon gene (gcg) and thereby produce the peptide hormone glucagon, which stimulates hepatic glucose production and thereby increases blood glucose levels. The same gcg gene is also expressed in the intestinal endocrine L cells and certain neural cells in the brain. In the gut, gcg expression leads to the production of glucagon-like peptide-1 (GLP-1). This incretin hormone stimulates insulin secretion when blood glucose level is high. In addition, GLP-1 stimulates pancreatic cell proliferation, inhibits cell apoptosis, and has been utilized in the trans-differentiation of insulin producing cells. Today, a long-term effective GLP-1 receptor agonist has been developed as a drug in treating diabetes and potentially other metabolic disorders. Extensive investigations have shown that the expression of gcg and the production of GLP-1 can be activated by the elevation of the second messenger cyclic AMP (cAMP). Recent studies suggest that in addition to protein kinase A (PKA), exchange protein activated by cAMP (Epac), another effector of cAMP signaling, and the crosstalk between PKA and Wnt signaling pathway, are also involved in cAMP-stimulated gcg expression and GLP-1 production. Furthermore, functions of GLP-1 in pancreatic cells are mainly mediated by cAMP-PKA, cAMP-Epac and Wnt signaling pathways as well.

  9. Ghrelin Attenuates Intestinal Barrier Dysfunction Following Intracerebral Hemorrhage in Mice

    PubMed Central

    Cheng, Yijun; Wei, Yongxu; Yang, Wenlei; Cai, Yu; Chen, Bin; Yang, Guoyuan; Shang, Hanbing; Zhao, Weiguo

    2016-01-01

    Intestinal barrier dysfunction remains a critical problem in patients with intracerebral hemorrhage (ICH) and is associated with poor prognosis. Ghrelin, a brain-gut peptide, has been shown to exert protection in animal models of gastrointestinal injury. However, the effect of ghrelin on intestinal barrier dysfunction post-ICH and its possible underlying mechanisms are still unknown. This study was designed to investigate whether ghrelin administration attenuates intestinal barrier dysfunction in experimental ICH using an intrastriatal autologous blood infusion mouse model. Our data showed that treatment with ghrelin markedly attenuated intestinal mucosal injury at both histomorphometric and ultrastructural levels post-ICH. Ghrelin reduced ICH-induced intestinal permeability according to fluorescein isothiocyanate conjugated-dextran (FITC-D) and Evans blue extravasation assays. Concomitantly, the intestinal tight junction-related protein markers, Zonula occludens-1 (ZO-1) and claudin-5 were upregulated by ghrelin post-ICH. Additionally, ghrelin reduced intestinal intercellular adhesion molecule-1 (ICAM-1) expression at the mRNA and protein levels following ICH. Furthermore, ghrelin suppressed the translocation of intestinal endotoxin post-ICH. These changes were accompanied by improved survival rates and an attenuation of body weight loss post-ICH. In conclusion, our results suggest that ghrelin reduced intestinal barrier dysfunction, thereby reducing mortality and weight loss, indicating that ghrelin is a potential therapeutic agent in ICH-induced intestinal barrier dysfunction therapy. PMID:27929421

  10. Vitamin D and intestinal calcium absorption.

    PubMed

    Christakos, Sylvia; Dhawan, Puneet; Porta, Angela; Mady, Leila J; Seth, Tanya

    2011-12-05

    The principal function of vitamin D in calcium homeostasis is to increase calcium absorption from the intestine. Calcium is absorbed by both an active transcellular pathway, which is energy dependent, and by a passive paracellular pathway through tight junctions. 1,25Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) the hormonally active form of vitamin D, through its genomic actions, is the major stimulator of active intestinal calcium absorption which involves calcium influx, translocation of calcium through the interior of the enterocyte and basolateral extrusion of calcium by the intestinal plasma membrane pump. This article reviews recent studies that have challenged the traditional model of vitamin D mediated transcellular calcium absorption and the crucial role of specific calcium transport proteins in intestinal calcium absorption. There is also increasing evidence that 1,25(OH)(2)D(3) can enhance paracellular calcium diffusion. The influence of estrogen, prolactin, glucocorticoids and aging on intestinal calcium absorption and the role of the distal intestine in vitamin D mediated intestinal calcium absorption are also discussed.

  11. Short communication: Promotion of glucagon-like peptide-2 secretion in dairy calves with a bioactive extract from Olea europaea.

    PubMed

    Morrison, S Y; Pastor, J J; Quintela, J C; Holst, J J; Hartmann, B; Drackley, J K; Ipharraguerre, I R

    2017-03-01

    Diarrhea episodes in dairy calves involve profound alterations in the mechanism controlling gut barrier function that ultimately compromise intestinal permeability to macromolecules, including pathogenic bacteria. Intestinal dysfunction models suggest that a key element of intestinal adaptation during the neonatal phase is the nutrient-induced secretion of glucagon-like peptide (GLP)-2 and associated effects on mucosal cell proliferation, barrier function, and inflammatory response. Bioactive molecules found in Olea europaea have been shown to induce the release of regulatory peptides from model enteroendocrine cells. The ability to enhance GLP-2 secretion via the feeding of putative GLP-2 secretagogues is untested in newborn calves. The objectives of this study were to determine whether feeding a bioactive extract from Olea europaea (OBE) mixed in the milk replacer (1) can stimulate GLP-2 secretion beyond the response elicited by enteral nutrients and, thereby, (2) improve intestinal permeability and animal growth as well as (3) reduce the incidence of diarrhea in preweaning dairy calves. Holstein heifer calves (n = 60) were purchased, transported to the research facility, and blocked by body weight and total serum protein and assigned to 1 of 3 treatments. Treatments were control (CON), standard milk replacer (MR) and ad libitum starter; CON plus OBE added into MR at 30 mg/kg of body weight (OBE30); and CON plus OBE added into MR at 60 mg/kg of body weight (OBE60). The concentration of GLP-2 was measured at the end of wk 2. Intestinal permeability was measured at the onset of the study and the end of wk 2 and 6, with lactulose and d-mannitol as markers. Treatments did not affect calf growth and starter intake. Compared with CON, administration of OBE60 increased the nutrient-induced response in GLP-2 by about 1 fold and reduced MR intake during the second week of study. Throughout the study, however, all calves had compromised intestinal permeability and a high

  12. The release of GLP-1 and ghrelin, but not GIP and CCK, by glucose is dependent upon the length of small intestine exposed.