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Sample records for intestinal peptide stimulates

  1. Vasoactive intestinal peptide stimulates tracheal submucosal gland secretion in ferret

    SciTech Connect

    Peatfield, A.C.; Barnes, P.J.; Bratcher, C.; Nadel, J.A.; Davis, B.

    1983-07-01

    We studied the effect of vasoactive intestinal peptide (VIP) on the output of 35S-labeled macromolecules from ferret tracheal explants either placed in beakers or suspended in modified Ussing chambers. In Ussing chamber experiments, the radiolabel precursor, sodium (35S)sulfate, and all drugs were placed on the submucosal side of the tissue. Washings were collected at 30-min intervals from the luminal side and were dialyzed to remove unbound 35S, leaving radiolabeled macromolecules. Vasoactive intestinal peptide at 3 X 10(-7) M stimulated bound 35S output by a mean of + 252.6% (n . 14). The VIP response was dose-dependent with a near maximal response and a half maximal response at approximately 10(-6) M and 10(-8), M, respectively. The VIP effect was not inhibited by a mixture of tetrodotoxin, atropine, I-propranolol, and phentolamine. Vasoactive intestinal peptide had no effect on the electrical properties of the of the tissues. We conclude that VIP stimulates output of sulfated-macromolecules from ferret tracheal submucosal glands without stimulating ion transport. Our studies also suggest that VIP acts on submucosal glands via specific VIP receptors. Vasoactive intestinal peptide has been shown to increase intracellular levels of cyclic AMP, and we suggest that this may be the mechanism for its effect on the output of macromolecules. This mechanism may be important in the neural regulation of submucosal gland secretion.

  2. 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

  3. Glucagonlike peptide 2 analogue teduglutide: stimulation of proliferation but reduction of differentiation in human Caco-2 intestinal epithelial cells.

    PubMed

    Chaturvedi, Lakshmi S; Basson, Marc D

    2013-11-01

    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. To test the hypothesis that teduglutide impairs human intestinal epithelial differentiation. 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. Cells were exposed to teduglutide or vehicle control. 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. The MTS assay demonstrated that teduglutide increased cell numbers by a mean (SD) of 10% (2%) over untreated controls at a maximal 500 nM (n = 6, P < .05). Teduglutide increased bromodeoxyuridine-positive cells vs untreated controls by a mean (SD) of 19.4% (2.3%) vs 12.0% (0.8%) (n = 6, P < .05) and increased the S-phase fraction

  4. Chronic stimulation of the hypothalamic vasoactive intestinal peptide receptor lengthens circadian period in mice and hamsters

    PubMed Central

    Pantazopoulos, Harry; Dolatshad, Hamid

    2010-01-01

    Evidence suggests that circadian rhythms are regulated through diffusible signals generated by the suprachiasmatic nucleus (SCN). Vasoactive intestinal peptide (VIP) is located in SCN neurons positioned to receive photic input from the retinohypothalamic tract and transmit information to other SCN cells and adjacent hypothalamic areas. Studies using knockout mice indicate that VIP is essential for synchrony among SCN cells and for the expression of normal circadian rhythms. To test the hypothesis that VIP is also an SCN output signal, we recorded wheel-running activity rhythms in hamsters and continuously infused the VIP receptor agonist BAY 55-9837 in the third ventricle for 28 days. Unlike other candidate output signals, infusion of BAY 55-9837 did not affect activity levels. Instead, BAY 55-9837 lengthened the circadian period by 0.69 ± 0.04 h (P < 0.0002 compared with controls). Period returned to baseline after infusions. We analyzed the effect of BAY 55-9837 on cultured SCN from PER2::LUC mice to determine if lengthening of the period by BAY 55-9837 is a direct effect on the SCN. Application of 10 μM BAY 55-9837 to SCN in culture lengthened the period of PER2 luciferase expression (24.73 ± 0.24 h) compared with control SCN (23.57 ± 0.26, P = 0.01). In addition, rhythm amplitude was significantly increased, consistent with increased synchronization of SCN neurons. The effect of BAY 55-9837 in vivo on period is similar to the effect of constant light. The present results suggest that VIP-VPAC2 signaling in the SCN may play two roles, synchronizing SCN neurons and setting the period of the SCN as a whole. PMID:20463182

  5. 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

  6. 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.

  7. 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.

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

    PubMed Central

    George, F W; Ojeda, S R

    1987-01-01

    We have investigated the factors that regulate aromatase activity in fetal-neonatal rat ovaries. Ovarian aromatase activity (assessed by measuring the amount of 3H2O) formed from [1 beta-3H]testosterone) is low prior to birth (less than 0.5 pmol/hr per mg of protein) 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 (postnatal days 2-4) 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 (0.1-1 microgram/ml), ovine luteinizing hormone (0.1 microgram/ml), 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 endogenous 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. Images PMID:3039508

  9. Vasoactive Intestinal Peptide: A Possible Transmitter of Nonadrenergic Relaxation of Guinea Pig Airways

    NASA Astrophysics Data System (ADS)

    Matsuzaki, Yoshikazu; Hamasaki, Yuhei; Said, Sami I.

    1980-12-01

    Vasoactive intestinal peptide, a smooth-muscle relaxant neuropeptide with neurotransmitter properties, was released during electrical field stimulation of guinea pig trachea. The amount released correlated with the degree of relaxation, and the release was blocked by tetrodotoxin. Prior incubation of the trachea with antiserum to vasoactive intestinal peptide reduced the relaxation. Thus vasoactive intestinal peptide may mediate the nonadrenergic relaxation of tracheal smooth muscle.

  10. 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

  11. Intestinal digestive resistance of immunodominant gliadin peptides.

    PubMed

    Hausch, Felix; Shan, Lu; Santiago, Nilda A; Gray, Gary M; Khosla, Chaitan

    2002-10-01

    Two recently identified immunodominant epitopes from alpha-gliadin account for most of the stimulatory activity of dietary gluten on intestinal and peripheral T lymphocytes in patients with celiac sprue. The proteolytic kinetics of peptides containing these epitopes were analyzed in vitro using soluble proteases from bovine and porcine pancreas and brush-border membrane vesicles from adult rat intestine. We showed that these proline-glutamine-rich epitopes are exceptionally resistant to enzymatic processing. Moreover, as estimated from the residual peptide structure and confirmed by exogenous peptidase supplementation, dipeptidyl peptidase IV and dipeptidyl carboxypeptidase I were identified as the rate-limiting enzymes in the digestive breakdown of these peptides. A similar conclusion also emerged from analogous studies with brush-border membrane from a human intestinal biopsy. Supplementation of rat brush-border membrane with trace quantities of a bacterial prolyl endopeptidase led to the rapid destruction of the immunodominant epitopes in these peptides. These results suggest a possible enzyme therapy strategy for celiac sprue, for which the only current therapeutic option is strict exclusion of gluten-containing food.

  12. Neuro-hormonal control of bone metabolism: vasoactive intestinal peptide stimulates alkaline phosphatase activity and mRNA expression in mouse calvarial osteoblasts as well as calcium accumulation mineralized bone nodules.

    PubMed

    Lundberg, P; Boström, I; Mukohyama, H; Bjurholm, A; Smans, K; Lerner, U H

    1999-11-30

    Based upon the immunohistochemical demonstration of neuropeptides in the skeleton, including vasoactive intestinal peptide (VIP), we have addressed the question of whether neuropeptides may exert regulatory roles on bone tissue metabolism or not. In the present communication, we have investigated if VIP can affect anabolic processes in osteoblasts. Osteoblasts were isolated from neonatal mouse calvariae by time sequential enzyme-digestion and subsequently cultured for 2-28 days in the presence of VIP and other modulators of cyclic AMP formation. VIP (10(-6) M) stimulated ALP activity and calcium content. The cyclic AMP phosphodiesterase inhibitors ZK 62 711 (10(-4) M) and isobutyl-methylxanthine (10(-4) M) stimulated ALP activity and synergistically potentiated the effect of VIP. Neither VIP, nor isobutyl-methylxanthine or ZK 62 711, in the absence or presence of VIP, affected cell number. The stimulatory effect of VIP on ALP activity, in the presence of ZK 62 711, was dependent on time and concentration of VIP. The stimulatory effects of VIP and ZK 62 711 on ALP activity was seen also in cells stained for ALP. VIP (10(-6) M), in the presence of ZK 62 711 (10(-6) M), significantly enhanced mRNA for tissue non-specific ALP. VIP (10(-6) M), in the presence of ZK 62 711, stimulated cyclic AMP production. Forskolin and choleratoxin stimulated ALP activity and cyclic AMP formation in a concentration-dependent manner, without affecting cell number. VIP (10(-6) M) and ZK 62 711 (10(-5) M) stimulated, and their combination synergistically enhanced, calcium content in bone noduli. These data show that VIP, without affecting cell proliferation, can stimulate osteoblastic ALP biosynthesis and bone noduli formation by a mechanism mediated by cyclic AMP. Our observations suggest a possibility that anabolic processes in bone are under neurohormonal control.

  13. [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.

  14. The Noncaloric Sweetener Rebaudioside A Stimulates Glucagon-Like Peptide 1 Release and Increases Enteroendocrine Cell Numbers in 2-Dimensional Mouse Organoids Derived from Different Locations of the Intestine.

    PubMed

    van der Wielen, Nikkie; Ten Klooster, Jean Paul; Muckenschnabl, Susanne; Pieters, Raymond; Hendriks, Henk Fj; Witkamp, Renger F; Meijerink, Jocelijn

    2016-12-01

    Glucagon-like peptide 1 (GLP-1) contributes to satiety and plays a pivotal role in insulin secretion and glucose homeostasis. Similar to GLP-1, peptide YY (PYY) and cholecystokinin also influence food intake. The secretion of these hormones by enteroendocrine cells along the intestine is modulated by nutrients. Preparations from the Stevia rebaudiana plant, including rebaudioside A, are increasingly being used as noncaloric sweeteners. We investigated the effects of rebaudioside A on enteroendocrine cells by assessing both cell numbers as well as their secretory capacity in an organoid model. A 2-dimensional organoid model derived from duodenal, jejunal, and ileal crypts of a C57BL/6J mouse was developed and characterized with the use of gene expression and immunofluorescence. We stimulated these organoids with 10 mmol/L rebaudioside A for 1 h and measured their GLP-1, PYY, and cholecystokinin release. We also analyzed the effects of rebaudioside A on gene expression in enteroendocrine cells after an 18-h incubation. The 2-dimensional organoids contained crypt cells and differentiated villus cells, including enterocytes and goblet and enteroendocrine cells. These enteroendocrine cells stained positive for GLP-1, PYY, and serotonin. The cultured 2-dimensional organoids maintained their location-specific gene expression patterns. Compared with the control, rebaudioside A induced GLP-1 secretion 1.7-fold in the duodenum (P < 0.01), 2.2-fold in the jejunum (P < 0.01), and 4.3-fold in the ileum (P < 0.001). PYY release was increased by rebaudioside A 3-fold in the ileum compared with the control (P < 0.05). Long-term (18-h) stimulation with the sweetener induced the expression of the enteroendocrine-specific markers chromogranin A, glucagon, Pyy, and cholecystokinin 3.5- (P < 0.001), 3.5- (P < 0.001), 3.8- (P < 0.05), and 6.5-fold (P < 0.001), respectively. These results show novel ex vivo effects of rebaudioside A on enteroendocrine cells of the mouse small intestine

  15. 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.

  16. 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

  17. 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

  18. Peptide hydrolase activities of the mucosa of human small intestine

    PubMed Central

    Heizer, William D.; Laster, Leonard

    1969-01-01

    Few studies have been published on peptide hydrolase activities of human small intestine mucosa. We developed methods to screen tissue extracts for such enzymes and to quantitate hydrolase activities for dipeptides containing the aromatic amino acid L-phenylalanine. The screening procedure indicated glycyl-L-proline hydrolase activity was reduced in biopsy specimens from patients with flattened intestinal mucosa. To explore this further, we established optimal assay conditions for hydrolase activities (a) glycyl-L-proline, (b) L-phenylalanyl-L-proline, (c) L-alanyl-L-phenylalanine, and (d) L-phenylalanylglycine. Biopsy specimens from patients with various intestinal disorders, but without flattened mucosa, and from three patients with flattened mucosa, showed a disproportionate reduction in activities (a) and (b), with the reduction being significantly more marked in the latter patients. We suggest that intestinal imidopeptide hydrolase activities, such as (a) and (b), are sensitive to changes in intestinal disease generally, particularly to the altered physiology associated with flattening of the mucosa, and are secondary to, rather than a cause of, the intestinal pathology. Our finding that intestinal alkaline phosphatase activity tended to parallel imidopeptide hydrolase activity, and that activity (a) was partially localized to the particulate fraction of mucosal homogenate, suggested that imidopeptide hydrolase activities may be located in the microvilli of the intestinal epithelium and that, like alkaline phosphatase activity, they may be reduced in flattened mucosae, in part at least because of the pathologic changes in the microvilli. In our studies of control subjects we did not detect peptide hydrolase activity deficiency analogous to asymptomatic disaccharidase deficiency. Images PMID:5765024

  19. 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.

  20. 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

  1. 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.

  2. 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. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. 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.

  4. Expression of novel neurotrophin-1/B-cell stimulating factor-3 (NNT-1/BSF-3) in murine pituitary folliculostellate TtT/GF cells: pituitary adenylate cyclase-activating polypeptide and vasoactive intestinal peptide-induced stimulation of NNT-1/BSF-3 is mediated by protein kinase A, protein kinase C, and extracellular-signal-regulated kinase1/2 pathways.

    PubMed

    Vlotides, George; Zitzmann, Kathrin; Hengge, Sabine; Engelhardt, Dieter; Stalla, Gunter K; Auernhammer, Christoph J

    2004-02-01

    Novel neurotrophin-1/B cell stimulating factor-3 (NNT-1/BSF-3) is a gp130 cytokine potently stimulating corticotroph proopiomelanocortin gene expression and ACTH secretion by a Janus kinase-signal transducer and activator of transcription (JAK-STAT)-dependent mechanism. In the current study, we examined the regulation of NNT-1/BSF-3 mRNA expression in murine pituitary folliculostellate TtT/GF cells using Northern blot technique. A 5- to 9-fold and a 4- to 7-fold induction in NNT-1/BSF-3 mRNA expression was observed between 2 and 6 h stimulation with the protein kinase C (PKC) stimulus phorbol-12-myristate-13-acetate (100 nm) and the protein kinase A (PKA) stimulus Bu(2)cAMP (5 mm), respectively. Pituitary adenylate cyclase-activating polypeptide (PACAP-38, 50 nm) and vasoactive intestinal peptide (VIP, 50 nm) also stimulated NNT-1/BSF-3 mRNA expression 5- to 9-fold between 2 and 6 h. Preincubation with PKC and PKA inhibitors such as H-7 (20 microm), GF109203X (50 microm), and H-89 (50 microm) decreased the stimulatory effects of PACAP and VIP. Both PACAP-38 and VIP also rapidly induced ERK1/2 phosphorylation and their stimulatory effect on NNT-1/BSF-3 mRNA expression was reduced by the MAPK kinase/ERK kinase (MEK) inhibitor U0126 (10 microm). Dexamethasone (10(-7) m) was a potent inhibitor of phorbol-12-myristate-13-acetate-induced NNT-1/BSF-3 expression. RT-PCR analysis demonstrated TtT/GF cells to express the short and the hop variant but not the hip variant of the PACAP-1 receptor (PAC1-R). In addition, TtT/GF cells express the VIP/PACAP-2 receptor (VPAC2-R). In summary, NNT-1/BSF-3 is expressed in pituitary folliculostellate TtT/GF cells and induced by PKC-, PKA-, and ERK1/2-dependent mechanisms. The novel gp130 cytokine NNT-1/BSF-3 derived from folliculostellate cells might act as a paracrine neuroimmunoendocrine modulator of pituitary corticotroph function.

  5. 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

  6. Changes in small intestinal motility and related hormones by acupuncture stimulation at Zusanli (ST 36) in mice.

    PubMed

    Jang, Jung-Hee; Lee, Deuk-Joo; Bae, Chang-Hwan; Ha, Ki-Tae; Kwon, Sunoh; Park, Hi-Joon; Hahm, Dae-Hyun; Lee, Hyejung; Kim, Seungtae

    2017-03-01

    To clarify the effects of acupuncture stimulation at Zusanli (ST 36) on the hormonal changes. Eight-week-old male C57BL/6 mice received acupuncture stimulation at acupoint ST 36 or Quchi (LI 11) once a day for 3 or 5 days in the acupuncture-stimulated groups, but not received in the normal group (n=6 in each group). On day 3 or 5, animals were given 0.1 mL of charcoal orally with a bulbed steel needle, 30 min after the last acupuncture stimulation. Ten minutes later, mice were anesthetized, and the intestinal transit and the concentrations of vasoactive intestinal peptide (VIP), motilin, ghrelin and gastrin in the serum were measured. Compared to no acupuncture stimulation, acupuncture stimulation at ST 36 for 5 days increased the intestinal transit and down-regulated the concentration of VIP and up-regulated the concentrations of motilin, ghrelin and gastrin (P<0.05 or 0.01), whereas acupuncture stimulation at LI 11 did not change them signifificantly (P>0.05). Acupuncture stimulation at ST 36 for 5 days enhances the small intestinal motility and regulates the secretion of hormones related to small intestinal motility.

  7. 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.

  8. Intestinal immunomodulation. Role of regulative peptides and promising pharmacological activities.

    PubMed

    Motilva, V; Talero, E; Calvo, J R; Villegas, I; Alarcón-de-la-Lastra, C; Sánchez-Fidalgo, S

    2008-01-01

    About 50 peptides, and a similar number of peptide receptors, are known to be present in the gut and this amount is likely to rise significantly over the next few years. While there has been a massive research effort to define their functions and their anatomical distribution in the central nervous system (CNS), the understanding of their roles in the gut is far more limited. Classically, the physiological functions include the control of motility, fluids, electrolytes, and digestive enzymes secretion, or vascular and visceral pain function, and more recently, the role-played in cell proliferation and survival, and in immune-inflammatory responses. The term inflammatory bowel disease (IBD) that encompasses Crohn's disease and ulcerative colitis, is clearly an inflammatory disease where several mediators such as cytokines, chemokines, prostanoids, nitric oxide or free radicals, produced by infiltrating cells, play a critical role in intestine tissue alteration. Some peptides, initially known for their neuroregulative properties, have been suggested to act as endogenous immune factors, with predominant antiinflammatory effects. Based on these actions, these molecules are proposed as potential agents for the treatment of IBD and selective peptide analogs are being developed as novel therapeutic strategies for IBD patients. Patients with IBD have an increased risk for developing colorectal cancer (CRC). Up to the present time, no known genetic basis has been identified to explain CRC predisposition in these IBD. Instead, it is assumed that chronic inflammation is what causes cancer. This is supported by the fact that colon cancer risk increases with longer duration of colitis, greater anatomic extent of colitis, the concomitant presence of other inflammatory manifestations, and the fact that certain drugs used to treat inflammation, may prevent the development of CRC. However, though different regulative peptides play a beneficial role in experimental IBD, an

  9. Vasoactive intestinal peptide (VIP) receptors in the canine gastrointestinal tract

    SciTech Connect

    Zimmerman, R.P.; Gates, T.S.; Mantyh, C.R.; Vigna, S.R.; Boehmer, C.G.; Mantyh, P.W.

    1988-11-01

    Vasoactive intestinal peptide (VIP) is a putative neurotransmitter in both the brain and peripheral tissues. To define possible target tissues of VIP we have used quantitative receptor autoradiography to localize and quantify the distribution of /sup 125/I-VIP receptor binding sites in the canine gastrointestinal tract. While the distribution of VIP binding sites was different for each segment examined, specific VIP binding sites were localized to the mucosa, the muscularis mucosa, the smooth muscle of submucosal arterioles, lymph nodules, and the circular and longitudinal smooth muscle of the muscularis externa. These results identify putative target tissues of VIP action in the canine gastrointestinal tract. In correlation with physiological data, VIP sites appear to be involved in the regulation of a variety of gastrointestinal functions including epithelial ion transport, gastric secretion, hemodynamic regulation, immune response, esophageal, gastric and intestinal motility.

  10. Intravenous Glucose Acutely Stimulates Intestinal Lipoprotein Secretion in Healthy Humans.

    PubMed

    Xiao, Changting; Dash, Satya; Morgantini, Cecilia; Lewis, Gary F

    2016-07-01

    Increased production of intestinal triglyceride-rich lipoproteins (TRLs) contributes to dyslipidemia and increased risk of atherosclerotic cardiovascular disease in insulin resistance and type 2 diabetes. We have previously demonstrated that enteral glucose enhances lipid-stimulated intestinal lipoprotein particle secretion. Here, we assessed whether glucose delivered systemically by intravenous infusion also enhances intestinal lipoprotein particle secretion in humans. On 2 occasions, 4 to 6 weeks apart and in random order, 10 healthy men received a constant 15-hour intravenous infusion of either 20% glucose to induce hyperglycemia or normal saline as control. Production of TRL-apolipoprotein B48 (apoB48, primary outcomes) and apoB100 (secondary outcomes) was assessed during hourly liquid-mixed macronutrient formula ingestion with stable isotope enrichment and multicompartmental modeling, under pancreatic clamp conditions to limit perturbations in pancreatic hormones (insulin and glucagon) and growth hormone. Compared with saline infusion, glucose infusion induced both hyperglycemia and hyperinsulinemia, increased plasma triglyceride levels, and increased TRL-apoB48 concentration and production rate (P<0.05), without affecting TRL-apoB48 fractional catabolic rate. No significant effect of hyperglycemia on TRL-apoB100 concentration and kinetic parameters was observed. Short-term intravenous infusion of glucose stimulates intestinal lipoprotein production. Hyperglycemia may contribute to intestinal lipoprotein overproduction in type 2 diabetes. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02607839. © 2016 American Heart Association, Inc.

  11. 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.

  12. Adrenocorticotrophic and melanocyte-stimulating peptides in the human pituitary

    PubMed Central

    Scott, Alexander P.; Lowry, Philip J.

    1974-01-01

    The adrenocorticotrophic and melanocyte-stimulating peptides of the human pituitary were investigated by means of radioimmunoassay, bioassay and physicochemical procedures. Substantial amounts of adrenocorticotrophin and a peptide resembling β-lipotrophin were identified in pituitary extracts, but α-melanocyte-stimulating hormone, β-melanocyte-stimulating hormone and corticotrophin-like intermediate lobe peptide, which have been identified in the pars intermedia of pituitaries from other vertebrates, were not found. The absence of β-melanocyte-stimulating hormone appears to contradict previous chemical and radioimmunological studies. Our results suggest, however, that it is not a natural pituitary peptide but an artefact formed by enzymic degradation of β-lipotrophin during extraction. PMID:4368382

  13. In vitro studies on intestinal peptide transport in horses.

    PubMed

    Cehak, A; Schröder, B; Feige, K; Breves, G

    2013-11-01

    Published data on the physiology of nutrient transport across the equine intestine are limited, and the existence and relevance of peptide transporters are still unknown in the horse. In the present study, the equine intestinal peptide transport was investigated by Ussing chamber experiments using the radioisotope tracer technique and by uptake studies into brush border membrane vesicles (BBMV). Jejunal mucosae of 16 healthy adult horses were used. Tissue samples were mounted in Ussing chambers, and electrophysiological parameters as well as unidirectional flux rates of the radiolabelled dipeptide glycylglutamine (Gly-Gln) were determined. The short-circuit current (Isc) response to the luminal addition of Gly-Gln was significantly greater compared to the Isc response to glycylsarcosine (Gly-Sar) addition (P<0.01). Positive net flux rates were determined indicating absorption of the dipeptide. The addition of Gly-Sar reduced the flux rates significantly (P<0.01), suggesting that both peptides compete for the same transport system. The flux rates were not affected by changes in luminal pH value. Uptake studies into BBMV demonstrated an uphill transport in both the absence and the presence of an inwardly directed H+-gradient with the H+-mediated uphill transport being significantly greater than the transport under equilibrium conditions (P<0.001). A Na+-gradient did not cause an uphill transport. The Gly-Gln uptakes displayed Michaelis-Menten kinetics with the Km value for the H+-dependent Gly-Gln uptake being significantly different from the Km value for the Gly-Gln uptake under equilibrium conditions (P<0.05). In conclusion, the study demonstrated for the first time that dipeptides are transcellularly transported across the equine small intestine. The results indicate the presence of at least 2 transport systems for peptide absorption in the horse: 1 secondary active H+-mediated cotransport and 1 that is capable of an uphill transport energized by a mechanism other

  14. 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.

  15. 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.

  16. Characterization of autoantibodies to vasoactive intestinal peptide in asthma.

    PubMed

    Paul, S; Said, S I; Thompson, A B; Volle, D J; Agrawal, D K; Foda, H; de la Rocha, S

    1989-07-01

    Vasoactive intestinal peptide (VIP) is a potent relaxant of the airway smooth muscle. In this study, VIP-binding autoantibodies were observed in the plasma of 18% asthma patients and 16% healthy subjects. Immunoprecipitation studies and chromatography on DEAE-cellulose and immobilized protein G indicated that the plasma VIP-binding activity was largely due to IgG antibodies. Saturation analysis of VIP binding by the plasmas suggested the presence of one or two classes of autoantibodies, distinguished by their apparent equilibrium affinity constants (Ka). The autoantibodies from asthma patients exhibited a larger VIP-binding affinity compared to those from healthy subjects (Ka 7.8 x 10(9) M-1 and 0.13 x 10(9) M-1, respectively; P less than 0.005). The antibodies were specific for VIP, judged by their poor reaction with peptides bearing partial sequence homology with VIP (peptide histidine isoleucine, growth hormone releasing factor and secretin). IgG prepared from the plasma of an antibody-positive asthma patient inhibited the saturable binding of 125I-VIP by receptors in guinea pig lung membranes (by 39-59%; P less than 0.001). These observations are consistent with a role for the VIP autoantibodies in the airway hyperresponsiveness of asthma.

  17. 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.

  18. 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

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

    USDA-ARS?s Scientific Manuscript database

    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...

  20. 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.

  1. Expression and localization of VPAC1, the major receptor of vasoactive intestinal peptide along the length of the intestine.

    PubMed

    Jayawardena, Dulari; Guzman, Grace; Gill, Ravinder K; Alrefai, Waddah A; Onyuksel, Hayat; Dudeja, Pradeep K

    2017-07-01

    Vasoactive intestinal peptide (VIP) is an endogenous neuropeptide with a broad array of physiological functions in many organs including the intestine. Its actions are mediated via G protein-coupled receptors, and vasoactive intestinal peptide receptor 1 (VPAC1) is the key receptor responsible for majority of VIP's biological activity. The distribution of VPAC1 along the length of the gastrointestinal tract and its subcellular localization in intestinal epithelial cells have not been fully characterized. The current studies were undertaken to determine VPAC1 distribution and localization so that VIP-based therapies can be targeted to specific regions of the intestine. The results indicated that the mRNA levels of VPAC1 showed an abundance pattern of colon > ileum > jejunum in the mouse intestine. In parallel, the VPAC1 protein levels were higher in the mouse colon, followed by the ileum and jejunum. Immunofluorescence studies in mouse colon demonstrated that the receptor was specifically localized to the luminal surface, as was evident by colocalization with the apical marker villin but not with the basolateral marker Na(+)/K(+)-ATPase. In the human intestine, VPAC1 mRNA expression exhibited a distribution similar to that in mouse intestine and was highest in the sigmoid colon. Furthermore, in the human colon, VPAC1 also showed predominantly apical localization. The physiological relevance of the expression and apical localization of VPAC1 remains elusive. We speculate that apical VPAC1 in intestinal epithelial cells may have relevance in recognizing secreted peptides in the intestinal lumen and therefore supports the feasibility of potential therapeutic and targeting use of VIP formulations via oral route to treat gastrointestinal diseases.NEW & NOTEWORTHY These studies for the first time present comprehensive data on the relative characterization of vasoactive intestinal peptide (VIP) receptors in the intestinal mucosa. Vasoactive intestinal peptide receptor 1

  2. Trigeminal ganglion cells cocultured with gut express vasoactive intestinal peptide.

    PubMed

    Davis, J P; Epstein, M L

    1987-12-01

    The plasticity of neural crest cells for the expression of adrenergic and cholinergic transmitter phenotypes has been well studied. The object of this study was to determine if cells of a sensory ganglion are capable of neuropeptide transmitter plasticity. We studied whether cells of the trigeminal ganglion, which do not express the neuropeptide vasoactive intestinal peptide (VIP) in vivo, would express this peptide when grown with a tissue the gut, that contains large numbers of VIP neurons. Embryonic aneural chick rectum was explanted with the embryonic quail trigeminal ganglion on the chorioallantoic membrane of chick hosts for 7-8 days. The explants were fixed, sectioned, and stained for VIP immunoreactivity (IR), for neurofilament protein immunoreactivity, and for the quail nucleolar marker. In sections of the explants we observed two populations of quail neurons: small (10-13 microns) VIP-IR cells and large (25-32 microns) cells lacking VIP-IR and resembling native trigeminal neurons. Trigeminal ganglia explanted with embryonic heart or trigeminal ganglia explanted alone lacked small VIP-IR cells but contained large VIP-negative neurons. These results show that cells of the trigeminal ganglion grown with the gut can express a neuropeptide they do not express in the absence of the gut or in vivo. Thus the embryonic trigeminal ganglion contains cells that are plastic with respect to neuropeptide expression.

  3. 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

  4. 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

  5. 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

  6. Lipopolysaccharides stimulate adrenomedullin synthesis in intestinal epithelial cells: release kinetics and secretion polarity.

    PubMed

    Kishikawa, Hiroshi; Nishida, Jiro; Ichikawa, Hitoshi; Kaida, Shogo; Morishita, Tetsuo; Miura, Soichiro; Hibi, Toshifumi

    2009-05-01

    Adrenomedullin (AM), a potent vasodilator peptide initially isolated from a human pheochromocytoma, functions as an antimicrobial peptide in host defense. In this study, we investigated changes in AM levels in intestinal epithelial cells and the mechanism of its secretion and cellular polarity after exposure to lipopolysaccharides (LPS). When a rat small intestinal cell line (IEC-18 cells) was exposed to LPS, enzyme-linked immunosorbent assay revealed a dose-dependent increase in AM together with an increase in AM mRNA expression, as determined by real-time polymerase chain reaction. Up-regulation of AM by LPS was dose-dependently inhibited by LY294002, PD98059, SP600125 and calphostin-C, suggesting the involvement of the phosphatidylinositol 3 kinase, extracellular signal-regulated kinase, c-Jun NH2-terminal kinase and protein kinase C pathways, respectively, in this process. When polarized IEC-18 cells in a Transwell chamber were stimulated with LPS, AM secretion was directed primarily toward the side of LPS administration (either the apical or basolateral side). In situ hybridization revealed that AM mRNA was expressed in epithelial cells and in the connective tissue in the lamina propria of the jejunum after intraperitoneal or oral administration of LPS. Higher levels of AM mRNA expression were observed in rats treated with LPS via the intraperitoneal route, compared with those treated via the oral route. These findings suggest that intestinal AM plays an important role in mucosal defense in the case of intestinal luminal infection, as well as in the modulation of hemodynamics in endotoxemia.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  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. 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.

  14. INTESTINAL DIGESTION AND ABSORPTION OF SUGARS AND PEPTIDES.

    DTIC Science & Technology

    Mammalian intestinal sucrase is activated by sodium in different ways in different species. The sodium-activation constants have been determined...Sodium-activation does not follow any compulsory reaction sequence. No diffusion barrier can be detected between lumen and intestinal sucrase ...Trehalase also shows a cooperative interaction between substrate sites. It is not activated by sodium. The intestinal sucrase -isomaltase complex can be

  15. 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

  16. 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

  17. 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

  18. Expression of ayu antimicrobial peptide genes after LPS stimulation

    PubMed Central

    NSRELDEN, Rehab Marray; HORIUCHI, Hiroyuki; FURUSAWA, Shuichi

    2017-01-01

    Plecoglossus altivelis (ayu) is one of the most important fish species in the Japanese islands and in internal fish hatcheries. Living in open aquatic environments exposes fish to many pathogens. Therefore, they require rapid and strong immune defenses. We investigated in vivo the direct association between the ayu innate immune response, represented by the relative transcription of genes encoding the cathelicidin and hepcidin antimicrobial peptides, and lipopolysaccharide (LPS), a conventional pathogen-associated molecular patterns (PAMPs) of Gram-negative bacteria. Different concentrations of LPS (1, 10 and 100 µg/fish) were injected intraperitoneally into young (sexually immature) and adult (fully sexually mature) ayu. The relative expression of the antimicrobial peptide genes was measured 6 hr, 24 hr and 1 week after stimulation with LPS. We found a direct association between the expression of the antimicrobial peptide genes investigated and LPS stimulation. This relationship was time-, dose- and age-dependent. Further research is required to determine the cell-specific transcriptional regulation and posttranscriptional regulation of these antimicrobial peptides. PMID:28484129

  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. Acylation of Glucagon-like peptide-2: interaction with lipid membranes and in vitro intestinal permeability.

    PubMed

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

    2014-01-01

    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. 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. 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. 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 membrane. Applying a transcellular absorption

  1. Intestinal absorption of the intact peptide carnosine in man, and comparison with intestinal permeability to lactulose.

    PubMed Central

    Gardner, M L; Illingworth, K M; Kelleher, J; Wood, D

    1991-01-01

    1. Healthy humans ingested the dipeptide carnosine (L-beta-alanyl-L-histidine). Their plasma levels and urinary outputs of carnosine and beta-alanine were monitored over the following 5 h. 2. Large amounts of intact carnosine (up to 14% of the ingested dose) were recovered in the urine over the 5 h after ingestion. However, carnosine was undetectable in the plasma unless precautions were taken to inhibit blood carnosinase activity ex vivo during and after blood collection. 3. The amount of carnosine recovered in urine varied substantially between subjects. It correlated negatively with carnosinase enzymic activity in the plasma. Highest carnosinase activities were observed in those subjects who regularly underwent physical training. 4. Urinary recovery of the disaccharide lactulose also varied considerably between subjects, but was substantially lower than that of carnosine. There was no significant correlation between the recoveries of carnosine and lactulose. 5. When lactulose was ingested with a hypertonic solution, the urinary recovery of lactulose was generally increased. When carnosine was ingested with a hypertonic solution, the urinary recovery of carnosine was reduced: hence the paracellular route probably is not dominant for absorption of intact carnosine. 6. Intact carnosine must have crossed the intestine to an extent much greater than hitherto recognized. Rapid post-absorptive hydrolysis is a severe obstacle to quantification of intact peptide absorption. PMID:1910085

  2. Synthesis and secretion of glucagon-like peptide-1 by fetal rat intestinal cells in culture.

    PubMed

    Jackson Huang, T H; Brubaker, P L

    1995-07-01

    Secretion of the intestinal proglucagon-derived peptides (PGDPs) including the incretin glucagon-like peptide-1 (GLP-1) is regulated, at least in part, by the duodenal hormone glucose-dependent insulinotropic peptide (GIP) through a protein kinase (PK) A-dependent pathway. It has been demonstrated that the activation of PKA increases the synthesis of some intestinal PGDPs, particularly the glucagon-like immunoreactive (GLI) peptides glicentin and oxyntomodulin. However, the effects of GIP on GLI and GLP-1 synthesis are not known. Fetal rat intestinal cells in culture were therefore treated for up to 24 h with 5MM: dbcAMP or 10(-6) M: GIP and the changes in glicentin, oxyntomodulin, GLP-1(x-37) and GLP-1(x-36NH2) secretion and synthesis were examined by RIA and HPLC. Both dbcAMP and GIP increased the acute (2 h; to 224±21 and 256±20% of controls, respectively,P<0.001) and chronic (24 h; to 230±22 and 130±6% of controls, respectively,P<0.001) secretion of intestinal PGDPs. In contrast, the total culture content of PGDPs was increased only after 24 h of incubation (to 156±15 and 125±7% of controls for dbcAMP and GIP, respectively,P<0.01). HPLC analysis confirmed that the intestinal cultures produced the GLI peptides glicentin and oxyntomodulin, as well as the biologically active forms of GLP-1, GLP-7(7-37) and GLP-1(7-36NH2). The relative proportion of these peptides was not altered by treatment with dbcAMP or GIP. Thus, in addition to its effects on GLP-1 release from the rat intestine, GIP appears to be an important regulator of the synthesis of this insulinotropic peptide.

  3. Prolonged treatment with transcutaneous electrical nerve stimulation (TENS) modulates neuro-gastric motility and plasma levels of vasoactive intestinal peptide (VIP), motilin and interleukin-6 (IL-6) in systemic sclerosis.

    PubMed

    McNearney, Terry A; Sallam, Hanaa S; Hunnicutt, Sonya E; Doshi, Dipti; Chen, Jiande D Z

    2013-01-01

    We assessed the effects of transcutaneous electrical nerve stimulation (TENS) on neurogastric functioning in scleroderma patients. Seventeen SSc patients underwent 30 min TENS treatment >10Hz at GI acupuncture points PC6 and ST36, once (acute TENS) and then after two weeks of TENS sessions for 30 min twice daily (prolonged TENS). Data collected at Visits 1 and 2 included gastric myoelectrical activity (GMA) by surface electrogastrography (EGG), heart rate variability (HRV) by surface electrocardiography (EKG), GI specific symptoms and health related SF-36 questionnaires. Plasma VIP, motilin and IL-6 levels were determined. Statistical analyses were performed by Student's t-test, Spearman Rank and p-values <0.05 were considered significant. 1. Only after prolonged TENS, the percentages of normal slow waves and average slow wave coupling (especially channels 1, 2 reflecting gastric pacemaker and corpus regions) were significantly increased; 2. the percentage of normal slow waves was significantly correlated to sympathovagal balance; 3. Mean plasma VIP and motilin levels were significantly decreased after acute TENS, (vs. baseline), generally maintained in the prolonged TENS intervals. Compared to baseline, mean plasma IL-6 levels were significantly increased after acute TENS, but significantly decreased after prolonged TENS. 4. After prolonged TENS, the frequency of awakening due to abdominal pain and abdominal bloating were significantly and modestly decreased, respectively. In SSc patients, two weeks of daily TENS improved patient GMA scores, lowered plasma VIP, motilin and IL-6 levels and improved association between GMA and sympathovagal balance. This supports the therapeutic potential of prolonged TENS to enhance gastric myoelectrical functioning in SSc.

  4. 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

  5. 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.

  6. Modulation of Chicken Intestinal Immune Gene Expression by Small Cationic Peptides as Feed Additives during the First Week Posthatch

    PubMed Central

    Genovese, Kenneth J.; He, Haiqi; Swaggerty, Christina L.; Jiang, Yiwei

    2013-01-01

    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 soil bacterium, Brevibacillus texasporus. These peptides have immune modulatory properties that enhance both leukocyte functional efficiency and leukocyte proinflammatory cytokine and chemokine mRNA transcription activities in vitro. In addition, when provided as a feed additive for just 4 days posthatch, BT peptides significantly induce a concentration-dependent protection against cecal and extraintestinal colonization by Salmonella enterica serovar Enteritidis. In the present studies, we assessed the effects of feeding BT peptides on transcriptional changes on proinflammatory cytokines, inflammatory chemokines, and Toll-like receptors (TLR) in the ceca of broiler chickens with and without S. Enteritidis infection. After feeding a BT peptide-supplemented diet for the first 4 days posthatch, chickens were then challenged with S. Enteritidis, and intestinal gene expression was measured at 1 or 7 days postinfection (p.i.) (5 or 11 days of age). Intestinal expression of innate immune mRNA transcripts was analyzed by quantitative real-time PCR (qRT-PCR). Analysis of relative mRNA expression showed that a BT peptide-supplemented diet did not directly induce the transcription of proinflammatory cytokine, inflammatory chemokine, type I/II interferon (IFN), or TLR mRNA in chicken cecum. However, feeding the BT peptide-supplemented diet primed cecal tissue for increased (P ≤ 0.05) transcription of TLR4, TLR15, and TLR21 upon infection with S. Enteritidis on days 1 and 7 p.i. Likewise, feeding the BT peptides primed the cecal tissue for increased transcription of proinflammatory cytokines (interleukin 1β [IL-1β], IL-6, IL-18, type I and II IFNs) and inflammatory chemokine (CxCLi2

  7. 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.

  8. CCR6 Deficiency Impairs IgA Production and Dysregulates Antimicrobial Peptide Production, Altering the Intestinal Flora

    PubMed Central

    Lin, Ya-Lin; Ip, Peng-Peng; Liao, Fang

    2017-01-01

    Intestinal immunity exists as a complex relationship among immune cells, epithelial cells, and microbiota. CCR6 and its ligand–CCL20 are highly expressed in intestinal mucosal tissues, such as Peyer’s patches (PPs) and isolated lymphoid follicles (ILFs). In this study, we investigated the role of the CCR6–CCL20 axis in intestinal immunity under homeostatic conditions. CCR6 deficiency intrinsically affects germinal center reactions in PPs, leading to impairments in IgA class switching, IgA affinity, and IgA memory B cell production and positioning in PPs, suggesting an important role for CCR6 in T-cell-dependent IgA generation. CCR6 deficiency impairs the maturation of ILFs. In these follicles, group 3 innate lymphoid cells are important components and a major source of IL-22, which stimulates intestinal epithelial cells (IECs) to produce antimicrobial peptides (AMPs). We found that CCR6 deficiency reduces IL-22 production, likely due to diminished numbers of group 3 innate lymphoid cells within small-sized ILFs. The reduced IL-22 levels subsequently decrease the production of AMPs, suggesting a critical role for CCR6 in innate intestinal immunity. Finally, we found that CCR6 deficiency impairs the production of IgA and AMPs, leading to increased levels of Alcaligenes in PPs, and segmented filamentous bacteria in IECs. Thus, the CCR6–CCL20 axis plays a crucial role in maintaining intestinal symbiosis by limiting the overgrowth of mucosa-associated commensal bacteria. PMID:28744287

  9. 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

  10. Vasoactive intestinal peptide inhibits fMLP-induced respiratory burst in human lymphocytes.

    PubMed

    Bellido, L; López-González, M A; Pedrera, C; Lucas, M

    1994-01-01

    N-Formyl-Methionyl-Leucyl-Phenylalanine (fMLP) induced in lymphocytes the production of reactive oxygen intermediates in a process which was inhibited by the presence of Vasoactive Intestinal Peptide (VIP) in a dose-dependent response at VIP concentrations in the range 10(-10)-10(-7) M. The dissociation constant for the high-affinity receptors of VIP agrees with the ID50 of the activation of adenylate cyclase which are close to 0.2 nM VIP, whereas the ID50 for the inhibition by VIP of fMLP-induced chemiluminescence approaches to 5 nM VIP. Both IBMX and Forskolin produced in lymphocytes an inhibition of fMLP-induced chemiluminescence. The degree of inhibition was ascertained to be additive in the presence of the above indicated agents and suboptimal concentrations of VIP. The saturation by cAMP of its putative target, the regulatory subunit of protein kinase A, appears to be required for the onset of the inhibitory effect of VIP. This study provides evidence of the molecular signal, namely cAMP, which provokes an inhibitory effect on chemoatractant-stimulated human lymphocytes and further support a role for VIP as a mediator in the neuroimmune system.

  11. Effects of exogenous glucagon-like peptide-2 and distal bowel resection on intestinal and systemic adaptive responses in rats.

    PubMed

    Lai, Sarah W; de Heuvel, Elaine; Wallace, Laurie E; Hartmann, Bolette; Holst, Jens J; Brindle, Mary E; Chelikani, Prasanth K; Sigalet, David L

    2017-01-01

    To determine the effects of exogenous glucagon-like peptide-2 (GLP-2), with or without massive distal bowel resection, on adaptation of jejunal mucosa, enteric neurons, gut hormones and tissue reserves in rats. GLP-2 is a gut hormone known to be trophic for small bowel mucosa, and to mimic intestinal adaptation in short bowel syndrome (SBS). However, the effects of exogenous GLP-2 and SBS on enteric neurons are unclear. Sprague Dawley rats were randomized to four treatments: Transected Bowel (TB) (n = 8), TB + GLP-2 (2.5 nmol/kg/h, n = 8), SBS (n = 5), or SBS + GLP-2 (2.5 nmol/kg/h, n = 9). SBS groups underwent a 60% jejunoileal resection with cecectomy and jejunocolic anastomosis. All rats were maintained on parenteral nutrition for 7 d. Parameters measured included gut morphometry, qPCR for hexose transporter (SGLT-1, GLUT-2, GLUT-5) and GLP-2 receptor mRNA, whole mount immunohistochemistry for neurons (HuC/D, VIP, nNOS), plasma glucose, gut hormones, and body composition. Resection increased the proportion of nNOS immunopositive myenteric neurons, intestinal muscularis propria thickness and crypt cell proliferation, which were not recapitulated by GLP-2 therapy. Exogenous GLP-2 increased jejunal mucosal surface area without affecting enteric VIP or nNOS neuronal immunopositivity, attenuated resection-induced reductions in jejunal hexose transporter abundance (SGLT-1, GLUT-2), increased plasma amylin and decreased peptide YY concentrations. Exogenous GLP-2 attenuated resection-induced increases in blood glucose and body fat loss. Exogenous GLP-2 stimulates jejunal adaptation independent of enteric neuronal VIP or nNOS changes, and has divergent effects on plasma amylin and peptide YY concentrations. The novel ability of exogenous GLP-2 to modulate resection-induced changes in peripheral glucose and lipid reserves may be important in understanding the whole-body response following intestinal resection, and is worthy of further study.

  12. 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…

  13. 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…

  14. Intestinal Digestion and Absorption of Sugars and Peptides.

    DTIC Science & Technology

    The sucrase -isomaltase complex, as prepared from the small intestine by papain solubilisation and Sephadex chromatography, has a ml. wt. of...approximately 190 000 and is composed of 6 subunits. Its amino acid composition, its content in SH and SS groups have been determined. The sucrase -isomaltase

  15. Enteroendocrine-derived glucagon-like peptide-2 controls intestinal amino acid transport.

    PubMed

    Lee, Jennifer; Koehler, Jacqueline; Yusta, Bernardo; Bahrami, Jasmine; Matthews, Dianne; Rafii, Mahroukh; Pencharz, Paul B; Drucker, Daniel J

    2017-03-01

    Glucagon-like peptide-2 (GLP-2) is co-secreted with GLP-1 from gut endocrine cells, and both peptides act as growth factors to expand the surface area of the mucosal epithelium. Notably, GLP-2 also enhances glucose and lipid transport in enterocytes; however, its actions on control of amino acid (AA) transport remain unclear. Here we examined the mechanisms linking gain and loss of GLP-2 receptor (GLP-2R) signaling to control of intestinal amino acid absorption in mice. Absorption, transport, and clearance of essential AAs, specifically lysine, were measured in vivo by Liquid Chromatography triple quadrupole Mass Spectrometry (LC-MS/MS) and ex vivo with Ussing chambers using intestinal preparations from Glp2r(+/+) and Glp2r(-/-) mice. Immunoblotting determined jejunal levels of protein components of signaling pathways (PI3K-AKT, and mTORC1-pS6-p4E-BP1) following administration of GLP-2, protein gavage, and rapamycin to fasted Glp2r(+/+) and Glp2r(-/-) mice. Expression of AA transporters from full thickness jejunum and 4F2hc from brush border membrane vesicles (BBMVs) was measured by real-time PCR and immunoblotting, respectively. Acute administration of GLP-2 increased basal AA absorption in vivo and augmented basal lysine transport ex vivo. GLP-2-stimulated lysine transport was attenuated by co-incubation with wortmannin, rapamycin, or tetrodotoxin ex vivo. Phosphorylation of mTORC1 effector proteins S6 and 4E-BP1 was significantly increased in wild-type mice in response to GLP-2 alone, or when co-administered with protein gavage, and abolished following oral gavage of rapamycin. In contrast, activation of GLP-1R signaling did not enhance S6 phosphorylation. Disruption of GLP-2 action in Glp2r(-/-) mice reduced lysine transport ex vivo and attenuated the phosphorylation of S6 and 4E-BP1 in response to oral protein. Moreover, the expression of cationic AA transporter slc7a9 in response to refeeding, and the abundance of 4F2hc in BBMVs following protein gavage

  16. Peptide-based optical contrast agents for targeting of intestinal malignancies

    NASA Astrophysics Data System (ADS)

    Röckendorf, Niels; Helfmann, Jürgen; Fujimoto, Naho; Wehry, Katrin; Bürger, Mario; Frey, Andreas

    2007-07-01

    Intestinal tumors exhibit cell surface properties that differ from neighboring healthy epithelia and thus allow tumor cell-specific molecular targeting. Ganglioside G M1 is such a discriminatory target. Although expressed in the apical membrane of all intestinal epithelial cells it is accessible for particle conjugated ligands on tumor cells only. In order to exploit this phenomenon we want to develop a nanoparticulate optical contrast agent equipped with a peptidic G M1 binding ligand. For identification of ligand peptides a novel screening platform was devised where potential ganglioside GM1-binding peptides are generated on glass capillary plates using microfluidic non-contact arraying techniques and screened in situ for binding of fluorophor-labeled G M1. These three-dimensional supports are easy to handle and show better sensitivity than either flat glass or membrane supports because of their large inner surface and low interference with readout systems. A custom fluorescence reader was designed to comply with the specific optical behaviour of peptide arrays synthesized on microcapillary plates. This reader uses a small numerical aperture for excitation and a large numerical aperture for detection in epifluorescence-mode. Background noise from fluorescence and Raman scattering is reduced by time gated photon counting. Peptides showing affinity to ganglioside G M1 will be conjugated to a nano-particulate carrier bearing a fluorescent dye. The resulting optical contrast agent shall be used for fluorescence endoscopic intestinal tumor screening.

  17. Chemical synthesis and characterization of silver-protected vasoactive intestinal peptide nanoparticles.

    PubMed

    Fernandez-Montesinos, Rafael; Castillo, Paula M; Klippstein, Rebecca; Gonzalez-Rey, Elena; Mejias, Jose A; Zaderenko, Ana P; Pozo, David

    2009-12-01

    We characterized a method to conjugate functional silver nanoparticles with vasoactive intestinal peptide (VIP), which could be used as a working model for further tailor-made applications based on VIP surface functionality. Despite sustained interest in the therapeutic applications of VIP, and the fact that its drugability could be largely improved by the attachament to functionalized metal nanoparticles, no methods have been described so far to obtain them. VIP was conjugated to tiopronin-capped silver nanoparticles of a narrow size distribution, by means of proper linkers, to obtain VIP functionalized silver nanoparticles with two different VIP orientations (Ag-tiopronin-PEG-succinic-[His]VIP and Ag-tiopronin-PEG-VIP[His]). VIP intermediate nanoparticles were characterized by transmission-electron microscopy and Fourier transform infrared spectroscopy. VIP functionalized silver nanoparticles cytotoxicity was determined by lactate dehydrogenase release from mixed glial cultures prepared from cerebral cortices of 1-3 days-old C57/Bl mice. Cells were used for lipopolysaccharide stimulation at day 18-22 of culture. Two different types of VIP-functionalized silver nanoparticles were obtained; both expose the C-terminal part of the neuropeptide, but in the first type VIP is attached to silver nanoparticle through its free amine terminus (Ag-tiopronin-PEG-succinic-[His]VIP), while in the second type, VIP N-terminus remains free (Ag-tiopronin-PEG-VIP[His]). VIP-functionalized silver nanoparticles did not compromise cellular viability and inhibited microglia-induced stimulation under inflammatory conditions. The chemical synthesis procedure developed to obtain VIP-functionalized silver nanoparticles rendered functional products, in terms of biological activity. The two alternative orientations designed, reduced the constraints for chemical synthesis that depends on the nanosurface to be functionalized. Our study provides, for the first time, a proof of principle to

  18. Genetic evidence for role of DPP IV in intestinal hydrolysis and assimilation of prolyl peptides.

    PubMed

    Tiruppathi, C; Miyamoto, Y; Ganapathy, V; Leibach, F H

    1993-07-01

    The functional role of dipeptidyl peptidase IV (DPP IV) in the intestinal hydrolysis and assimilation of prolyl peptides was investigated using Japan F344 rats, which genetically lack this enzyme. USA F344 rats possess normal activity of this enzyme and served as matched controls. Intestinal brush-border membranes from the control rats were able to hydrolyze several proline-containing peptides. The hydrolytic ability of the brush-border membranes from the Japan rats against these peptides was markedly low. The difference in the hydrolytic activities between the two groups of rats was solely due to the absence of DPP IV in the Japan rats. There was no difference in the growth rate between the two groups of rats fed a reference diet whose protein constituents were not rich in proline. When the protein source was changed to gliadin, a proline-rich protein, USA F344 rats maintained their body weight for a 4-wk period on this diet, whereas the Japan rats experienced a significant weight loss under similar conditions. In situ perfusion experiments in intact animals revealed that the ability of morphiceptin (a peptide primarily hydrolyzable by DPP IV), when administered into the intestinal lumen, to block the cholera toxin-induced water secretion was significantly greater in Japan F344 rats than in USA F344 rats, indicating the resistance of morphiceptin to hydrolytic breakdown in the intestinal lumen of the Japan rats. It is concluded that the intestinal DPP IV plays a significant role in the hydrolysis of prolyl peptides and assimilation of proline-rich proteins.

  19. 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.

  20. 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.

  1. INTESTINAL DIGESTION AND ABSORPTION OF SUGARS AND PEPTIDES.

    DTIC Science & Technology

    The allosteric properties of sucrase were investigated. There is an evident homologous interaction between Na-sites and between substrate-sites... Sucrase , which has no mutarotase activity, liberates glucose in its alpha form. The beta forms of glucose and of some of its derivatives are absorbed...preferentially. Human and rabbit intestinal sucrases were isolated. Antibodies against them were prepared. A new procedure for the measurement of

  2. 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.

  3. 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

  4. 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

  5. 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

  6. Intestinal absorption of amino acids and peptides in Hartnup disorder.

    PubMed

    Leonard, J V; Marrs, T C; Addison, J M; Burston, D; Clegg, K M; Lloyd, J K; Matthews, D M; Seakins, J W

    1976-04-01

    Absorption of free and peptide-bound amino acids was investigated in a girl with Hartnup disorder aged 26 months. Plasma levels of amino acids were followed after oral administration of (1) an amino acid mixture simulating casein and (2) an equivalent dose of a partial enzymic hydrolysate of casein containing oligopeptides in addition to free amino acids. The results suggested that many neutral amino acids were poorly absorbed when given in the free form, but much more readily absorbed when given as peptides. Unexpectedly, the results also suggested that glutamic acid was poorly absorbed when given in the free form. The results obtained with threonine could not be interpreted. There was an increased renal clearance of many neutral amino acids, including glycine, but clearance of proline was not increased. Most amino acids with an increased renal clearance also appeared to be poorly absorbed when given by mouth in the free form.

  7. 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.

  8. 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

  9. Digestion of gliadin peptides by intestinal mucosa from control or coeliac children.

    PubMed

    Carchon, H; Serrus, M; Eggermont, E

    1979-01-01

    Gliadin, subsequently treated with pepsin, trypsin and pancreatic extract was further digested by small-intestinal mucosal homogenates from 10 control or 8 coeliac children. The amino acids liberated in the incubation mixture were measured and corrected for mucosal damage. In accordance with the data from the literature on adults, the total amount of amino acids released from gliadin peptides by the intestinal mucosa from children with active coeliac disease is significantly lower than that by the mucosa from control subjects. Qualitatively, however, no significant differences for the individual amino acids are observed with the exception of glutamine and proline, so that damaged coeliac mucosa liberates relatively more glutamine but less proline.

  10. The effect of ferrous-chelating hairtail peptides on iron deficiency and intestinal flora in rats.

    PubMed

    Lin, Hui-Min; Deng, Shang-Gui; Huang, Sai-Bo; Li, Ying-Jie; Song, Ru

    2016-06-01

    Chelating agents, such as small peptides, can decrease free iron content and increase iron bioavailability. They may have promising therapeutic potential and may prevent the pro-oxidant effects of low molecular weight iron. Hairtail is a species of fish that is rich in easily digestible proteins. We extended this strategy for iron delivery by using an enzymatic hydrolysate of hairtail as the chelating agent and found that the ferrous-chelating hairtail peptides have anti-anaemic activity in Sprague-Dawley rats with anaemia. The anti-anaemic activity of ferrous-chelating hairtail peptides prepared by enzymatic hydrolysis of the hairtail and ferrous chelation was studied in rat models of iron deficiency anaemia. After the end of the 35 d experiment, we noted significant differences in haemoglobin, mean corpuscular volume, haemoglobin distribution width, and ferritin concentrations between those animals supplemented with ferrous-chelating hairtail peptides and FeSO4 and healthy animals. There were no negative side effects on the animals' growth or behaviour. There was no obvious inflammation in the intestinal mucosa lamina propria and no unbalance of intestinal flora. The novel ferrous-chelating hairtail peptides may be a suitable fortificant for improving iron-deficiency status. Our findings demonstrated that this multi-tracer technique has many applications in nutritional research. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  11. 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.

  12. Differential Effects on Intestinal Adaptation Following Exogenous Glucagon-Like Peptide 2 Therapy With and Without Enteral Nutrition in Neonatal Short Bowel Syndrome [Formula: see text].

    PubMed

    Lim, David W; Diané, Abdoulaye; Muto, Mitsuru; Vine, Donna F; Nation, Patrick N; Wizzard, Pamela R; Sigalet, David L; Bigam, David L; Pencharz, Paul B; Turner, Justine M; Wales, Paul W

    2017-02-01

    We aim to study the efficacy of exogenously administered glucagon-like peptide 2 (GLP-2) on intestinal adaptation in 2 preclinical models of neonatal short bowel syndrome (SBS) according to remnant intestinal anatomy, with and without ileum. Furthermore, we aim to determine if this adaptive effect was potentiated with enteral nutrition (EN). Neonatal piglets were block-randomized to 75% mid-intestinal (JI group, retains ileum) or distal-intestinal (JC group, has no ileum) resection or no resection (sham control) and GLP-2 treatment (11 nmol/kg/d) or saline control for 7 days. Piglets received nutrition support, either 100% parenteral nutrition (PN; 0% EN, n = 32 in total) or 80% PN + 40% EN (n = 28 in total). Adaptation was assessed by morphological and histological changes, as well as RT quantitative polymerase chain reaction of nutrient transporters and tight junctional proteins and fat absorption. Data are analyzed by 3-way analysis of variance (ANOVA) and 2-way ANOVA per EN level. GLP-2 treatment lengthened villi, deepened crypts, and improved intestinal weight in the remnant intestine of JC piglets. EN was a more potent adaptive stimulus for JI piglets. Small intestinal lengthening occurred only in the JI group, when given EN. There was no difference in total fat absorption and messenger RNA expression of nutrient transporters and tight junctional proteins. GLP-2 administration augmented structural adaptation in JC piglets with distal intestinal resection. Given JI anatomy, further stimulation by GLP-2 treatment over innate adaptation and stimulation by EN was modest and restricted to ileum. The differential effect of GLP-2 in neonatal SBS, depending on remnant anatomy, has important implications for clinical translation and planning of clinical trials.

  13. Intestinal protozoa are hypothesized to stimulate immunosurveillance against colon cancer.

    PubMed

    Juckett, David A; Aylsworth, Charles F; Quensen, Janet Murphy

    2008-01-01

    Colon cancer in humans results in considerable morbidity and mortality throughout most of the world. During the twentieth century, there was a rapid rise in colon cancer within modernizing countries that has not been adequately explained, although the role of diet has been widely explored. Previously, we showed that the presence of the endemic Eimeria spp. protozoan in intestinal tissues is associated with regions of low tumorigenesis in the large and small bovine intestine and that an Eimeria surface protein is a potent activator of dendritic cells and a useful immunomodulator, with anti-cancer and anti-viral properties. Therefore, we hypothesize that the persistent presence of such an intestinal protozoan enhances immunosurveillance by elevating the intestinal alert status and that the loss of these organisms could lead to a higher incidence of colon cancer. Preliminary support of this hypothesis derives from the observations that domestic animals, known to maintain this protozoan, have very low colon cancer incidence. We propose that this also may occur in human populations that use human excrement (night soil) as a fertilizer, a practice that serves to complete the life cycle of this type of microbe. We examine some evidence for this hypothesis in Japan's mortality patterns, where we show that colon cancer increased after the cessation of night soil use, but before the change to a western diet. We conclude that this hypothesis, a variation of the hygiene hypothesis, is worth further consideration and continued elaboration.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Steric and interactive barrier properties of intestinal mucus elucidated by particle diffusion and peptide permeation.

    PubMed

    Boegh, Marie; García-Díaz, María; Müllertz, Anette; Nielsen, Hanne Mørck

    2015-09-01

    The mucus lining of the gastrointestinal tract epithelium is recognized as a barrier to efficient oral drug delivery. Recently, a new in vitro model for assessment of drug permeation across intestinal mucosa was established by applying a biosimilar mucus matrix to the surface of Caco-2 cell monolayers. The aim of the present study was to gain more insight into the steric and interactive barrier properties of intestinal mucus by studying the permeation of peptides and model compounds across the biosimilar mucus as well as across porcine intestinal mucus (PIM). As PIM disrupted the Caco-2 cell monolayers, a cell-free mucus barrier model was implemented in the studies. Both the biosimilar mucus and the PIM reduced the permeation of the selected peptide drugs to varying degrees illustrating the interactive properties of both mucus matrices. The reduction in peptide permeation was decreased depending on the cationicity and H-bonding capacity of the permeant clearly demonstrated by using the biosimilar mucus, whereas the larger inter sample variation of the PIM matrix obstructed similarly clear conclusions. Thus, for mechanistic studies of permeation across mucus and mucosa the biosimilar mucus offers a relevant and reproducible alternative to native mucus. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. 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

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

    PubMed

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

    2015-01-14

    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. 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 14(th) 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. 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). GLP-2 reduces intestinal mucosal injuries in obstructive jaundice rats, which might be attributed to increased intestinal IgA and reduced bilirubin and endotoxin.

  2. 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.

  3. Starfish gonadotropic hormone: Relaxin-like gonad-stimulating peptides.

    PubMed

    Mita, Masatoshi

    2016-05-01

    Relaxin-like gonad-stimulating peptide (RGP) of starfish Patiria (= Asterina) pectinifera is the first identified invertebrate gonadotropin to trigger final gamete maturation. Recently, chemical structures of RGP were identified in several species of starfish. Three kinds of RGP molecules are found in the class Asteroidea. The chemical structure of P. pectinifera RGP (PpeRGP) is conserved among starfish of the order Valvatida beyond species. In contrast, the chemical structures of RGP identified in Asterias amurensis and Aphelasterias japonica of the order Forcipulatida are quite different from that of PpeRGP. The chemical structure of RGP in A. amurensis (AamRGP) is exactly the same as that in Asterias rubens (the order Forcipulatida), Astropecten scoparius (the order Paxillosida), Astropecten polyacanthus (the order Paxillosida), and Echinaster luzonicus (the order Spinulosida). The chemical structure of Coscinasterias acutispina RGP (the order Forcipulatida) is consistent with that of A. japonica RGP (AjaRGP). In cross-experiments using P. pectinifera, A. amurensis, and A. japonica ovaries, AamRGP and AjaRGP can induce each species of ovaries. Neither AamRGP nor AjaRGP induce oocyte maturation and ovulation in the ovary of P. pectinifera, although the PpeRGP is active in ovaries of A. amurensis and A. japonica. This suggests that the AamRGP and AjaRGP partly act species specificity. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Differential stimulation of S-adenosylmethionine decarboxylase by difluoromethylornithine in the rat colon and small intestine.

    PubMed Central

    Halline, A G; Dudeja, P K; Brasitus, T A

    1989-01-01

    The effects of chronic inhibition of ornithine decarboxylase (ODC) by the specific inhibitor difluoromethylornithine (DFMO) in the rat colon and small intestine on mucosal contents of polyamines, decarboxylated S-adenosylmethionine (decarboxylated AdoMet) and S-adenosylmethionine decarboxylase (AdoMet decarboxylase) activity were studied. Administration of 1% DFMO in the drinking water for 10 or 15 weeks resulted in inhibition of ODC and decreases in intracellular putrescine and spermidine contents in both proximal and distal segments of small intestine and colon. At both time points DFMO administration resulted in a dramatic stimulation of AdoMet decarboxylase activity and a rise in decarboxylated AdoMet content in the proximal and distal small-intestinal segments compared with controls, which was not seen in either colonic segment of DFMO-treated animals. This differential stimulation of AdoMet decarboxylase by DFMO in the small intestine and colon could not be entirely explained on the basis of differences in polyamine contents, which are known to regulate this enzyme activity. Kinetic and inhibition studies of AdoMet decarboxylase in control small and large intestine revealed that: (1) there was no difference in Vmax. values between the tissues; (2) the Km for AdoMet was higher in the small intestine than in the colon; and (3) the Ki for product inhibition by decarboxylated AdoMet was higher in the small intestine than in the colon. These results suggest that the differential stimulation of AdoMet decarboxylase by DFMO in the small intestine and colon may be due to different isoenzymes and could play a significant role in the regulation of polyamine contents throughout the gut. PMID:2497738

  5. Intestinal Metrnl released into the gut lumen acts as a local regulator for gut antimicrobial peptides.

    PubMed

    Li, Zhi-Yong; Fan, Mao-Bing; Zhang, Sai-Long; Qu, Yi; Zheng, Si-Li; Song, Jie; Miao, Chao-Yu

    2016-11-01

    Metrnl is a novel secreted protein, but its physiological roles remain elusive. In this study, we investigated the tissue expression pattern of Metrnl in humans and explored its possible physiological role in the tissues with most highly expressed levels. A human tissue microarray containing 19 types of tissues from 69 donors was used to examine the tissue expression pattern of Metrnl, and the expression pattern was further verified in fresh human and mouse tissues. Intestinal epithelial cell-specific Metrnl knockout mice were generated, which were used to analyze the physiological roles of Metrnl. Metrnl was the most highly expressed in the human gastrointestinal tract, and was specifically expressed in the intestinal epithelium. Consistent with this, Metrnl mRNA was also most highly expressed in the mouse gastrointestinal tract among the 14 types of tissues tested. In the intestinal epithelial cell-specific Metrnl knockout mice, the Metrnl levels in the gut fluid were significantly reduced, whereas the Metrnl serum levels showed a trend towards a reduction, but this change was not statistically significant. This cell-specific deletion of Metrnl did not affect body weight, food intake, blood glucose, colon length and histology, intestinal permeability, mucus content or mucin 2 expression under physiological conditions, but statistically decreased the expression of antimicrobial peptides, such as regenerating islet-derived 3 gamma (Reg3g) and lactotransferrin. Metrnl is highly expressed in the intestinal epithelial cells of humans and mice, which mainly contributes to the local gut Metrnl levels and affects the serum Metrnl level to a lesser extent. Metrnl plays a role in maintaining gut antimicrobial peptides.

  6. Endogenous opioid peptides, endomorphin-1 and -2 and deltorphin I, stimulate angiogenesis in the CAM assay.

    PubMed

    Dai, Xu; Cui, Shi-Gang; Wang, Ting; Liu, Qian; Song, Hong-Jin; Wang, Rui

    2008-01-28

    The opioid peptides modulate extensive bioactivities, including pain, cardiovascular response, development and so on. The effects of endogenous opioid peptides on angiogenesis were evaluated in the chick embryo chorioallantoic membrane (CAM) assay for the first time in the present study. Endomorphin-1, endomorphin-2 and deltorphin I at the dosage of 1, 10, 100 nmol/embryo could stimulate angiogenesis dose-dependently, respectively. Naloxone, the nonselective opioid receptor antagonist, did not influence angiogenesis alone; but it could antagonize the stimulative effects of the opioid peptides on angiogenesis when it was administrated in combination with the opioid peptides. Taken altogether, the results suggested that endogenous opioid peptides (endomorphin-1 and -2 and deltorphin I) stimulated angiogenesis in the CAM assay, and these effects were modulated with the opioid receptors. These data are important for potential future clinical implementation.

  7. 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.

  8. [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.

  9. 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.

  10. 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

  11. Synergistic airway gland mucus secretion in response to vasoactive intestinal peptide and carbachol is lost in cystic fibrosis

    PubMed Central

    Choi, Jae Young; Joo, Nam Soo; Krouse, Mauri E.; Wu, Jin V.; Robbins, Robert C.; Ianowski, Juan P.; Hanrahan, John W.; Wine, Jeffrey J.

    2007-01-01

    Cystic fibrosis (CF) is caused by dysfunction of the CF transmembrane conductance regulator (CFTR), an anion channel whose dysfunction leads to chronic bacterial and fungal airway infections via a pathophysiological cascade that is incompletely understood. Airway glands, which produce most airway mucus, do so in response to both acetylcholine (ACh) and vasoactive intestinal peptide (VIP). CF glands fail to secrete mucus in response to VIP, but do so in response to ACh. Because vagal cholinergic pathways still elicit strong gland mucus secretion in CF subjects, it is unclear whether VIP-stimulated, CFTR-dependent gland secretion participates in innate defense. It was recently hypothesized that airway intrinsic neurons, which express abundant VIP and ACh, are normally active and stimulate low-level gland mucus secretion that is a component of innate mucosal defenses. Here we show that low levels of VIP and ACh produced significant mucus secretion in human glands via strong synergistic interactions; synergy was lost in glands of CF patients. VIP/ACh synergy also existed in pig glands, where it was CFTR dependent, mediated by both Cl– and HCO3–, and clotrimazole sensitive. Loss of “housekeeping” gland mucus secretion in CF, in combination with demonstrated defects in surface epithelia, may play a role in the vulnerability of CF airways to bacterial infections. PMID:17853942

  12. 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

  13. Dietary fructo-oligosaccharides and lactulose inhibit intestinal colonisation but stimulate translocation of salmonella in rats

    PubMed Central

    Bovee-Oudenhoven, I M J; ten Bruggencate, S J M; Lettink-Wissink, M L G; van der Meer, R

    2003-01-01

    Background and aims: It is frequently assumed that dietary non-digestible carbohydrates improve host resistance to intestinal infections by stimulating the protective gut microflora. However, compelling scientific evidence from in vivo infection studies is lacking. Therefore, we studied the effect of several non-digestible carbohydrates on the resistance of rats to Salmonella enteritidis infection. Methods: Rats (n=8 per group) were fed “humanised” purified diets containing 4% lactulose, fructo-oligosaccharides (FOS), resistant starch, wheat fibre, or cellulose. After an adaptation period of 2 weeks the animals were orally infected with S enteritidis. Supplement induced changes in faecal biochemical and microbiological parameters were studied before infection. Colonisation of salmonella was determined by studying the faecal excretion of this pathogen and translocation by analysis of urinary nitric oxide metabolites over time and classical organ cultures. Intestinal mucosal myeloperoxidase activity was determined to quantify intestinal inflammation after infection. Results: Despite stimulation of intestinal lactobacilli and bifidobacteria and inhibition of salmonella colonisation, FOS and lactulose significantly enhanced translocation of this pathogen. These supplements also increased cytotoxicity of faecal water and faecal mucin excretion, which may reflect mucosal irritation. In addition, caecal and colonic, but not ileal, mucosal myeloperoxidase activity was increased in infected rats fed FOS and lactulose. In contrast, cellulose, wheat fibre, and resistant starch did not affect the resistance to salmonella. Conclusions: In contrast to most expectations, FOS and lactulose impair the resistance of rats to intestinal salmonella infection. Obviously, stimulation of the endogenous lactobacilli and bifidobacteria is no guarantee of improved host defence against intestinal infections. PMID:14570725

  14. [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.

  15. 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.

  16. Effects of Erythropoiesis-stimulating Agents on Intestinal Flora in Peritoneal Fibrosis.

    PubMed

    Bilici, Muammer; Oz, Ibrahim Ilker; Uygun Ilikhan, Sevil; Borazan, Ali

    2017-05-01

    This study aimed to investigate the effects of erythropoiesis-stimulating agents (ESAs) on intestinal flora in peritoneal fibrosis. Twenty-four Wistar albino rats were divided into 3 groups as the control group, which received 0.9% saline (3 mL/d) intraperitoneally; the chlorhexidine gluconate (CH) group, which received 3 mL/d injections of 0.1% CH intraperitoneally, and the ESA group, which received 3 mL/d injections of 0.1% CH intraperitoneally and epoetin beta (3 doses of 20 IU/kg/wk) subcutaneously. On the 21st day, the rats were sacrificed and the visceral peritoneum samples were obtained from left liver bowel. Blood samples were obtained from abdominal aorta and intestinal flora samples were obtained from transverse colon. Histopathologically, the CH, ESA, and control groups had peritoneal thickness of 135.4 ± 22.2 µm, 48.6 ± 12.8 µm, and 6.0 ± 2.3 µm, respectively. Escherichia coli was the predominant bacterium in the intestinal flora in the control group. Significant changes in microbial composition of intestinal flora towards Proteus species and Enterobacter species was seen among the groups (P < .001). There was no significant difference between the ESA and CH groups regarding the isolates from blood cultures. However, the bacterial isolates from cultures of intestinal flora among these groups were significantly different (P < .05). Erythropoiesis-stimulating agents change intestinal flora by a clinically significant amount in experimental peritoneal fibrosis. We consider that ESAs achieve this via regulating intestinal peristaltism.

  17. Investigation of the cytotoxicity of eukaryotic and prokaryotic antimicrobial peptides in intestinal epithelial cells in vitro.

    PubMed

    Maher, Sam; McClean, Siobhán

    2006-04-28

    Antimicrobial peptides (AMPs) are a diverse group of proteinaceous compounds ranging in size, complexity and antimicrobial spectrum. The activity of AMPs against gut pathogens warrants the study of the interaction of AMPs with the mammalian gastrointestinal tract. In particular, the investigation of the in vitro cytotoxicity of these peptides is critical before they can be considered in clinical infections. The cytotoxicity of gallidermin, nisin A, natural magainin peptides, and melittin was investigated in two gastrointestinal cell models (HT29 and Caco-2) with the MTT conversion assay, neutral red dye uptake assay and compared with that of vancomycin. The hemolytic activities were also investigated in sheep erythrocytes and the effect of AMPs on paracellular permeability was examined by transepithelial resistance (TEER) and TEM. Gallidermin was the least cytotoxic AMP followed by nisin A, magainin I, magainin II and melittin. Melittin and nisin were the only peptides to result in significant hemolysis. However, while nisin caused hemolysis at concentrations which were 1000-fold higher than those required for antimicrobial activity, melittin was hemolytic at concentrations in the same order of magnitude as its antimicrobial activity. Melittin was the only AMP to affect paracellular permeability. Long term melittin treatment also resulted in loss of microvilli, an increase in cell debris and destruction of intestinal tight junctions and cell-cell adhesion. Gallidermin shows most promise as a therapeutic agent, with relatively low cytotoxicity and potent antimicrobial activities. Melittin, while showing little potential as an antimicrobial agent, may have potential in delivery of poorly bioavailable drugs.

  18. Cosecretion of peptide histidine methionine (PHM) and vasoactive intestinal peptide (VIP) in patients with VIP-producing tumors.

    PubMed

    Fahrenkrug, J; Pedersen, J H

    1986-01-01

    Regional specific antibodies and chromatography were used to analyze the concentration and molecular forms of vasoactive intestinal peptide (VIP) and peptide histidine methionine (PHM) in plasma from 39 patients with VIP-producing tumors. Plasma VIP concentrations ranged from 29 to 2550 pmol/l and the corresponding PHM immunoreactive values measured with C-terminally directed antibody were 42 to 2100 pmol/l which correlated closely with the VIP concentrations. N-terminal PHM concentrations were significantly higher than the C-terminal values ranging from 92 to 5850 pmol/l and correlated poorly with the corresponding VIP concentrations. Infusion experiments with PHM disclosed that the higher levels of N-terminal immunoreactivity could not be explained by slower metabolic clearance or by degradation to smaller N-terminal immunoreactive forms. N-terminally directed PHM antibody revealed, in addition to intact PHM, a larger immunoreactive form in patient plasma which constituted the major proportion of the total immunoreactivity. In conclusion, VIP and PHM are cosecreted from VIPomas and measurement of PHM, especially N-terminal immunoreactivity, may be useful in this condition.

  19. 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.

  20. Preliminary study of an intestinal bio-robot system based on nerve stimulation

    PubMed Central

    2012-01-01

    Background Wireless capsule endoscopes for diagnosis and treatment in the gastrointestinal tract face the common problem of active actuation. To tackle this difficulty, a non-invasive intestinal bio-robot system with active actuation based on nerve stimulation was developed. Methods This intestinal inspection system utilized a natural organism—the mud eel—to serve as the locomotion mechanism, and it was controlled by a LabVIEW-programmed pulse generator. The exterior control unit was able to actively drive and remotely control the navigation and site-specific anchoring of the organism. Results Through in vitro stimulation experiments, a method of controlling the organism’s forward motion was obtained: when the organism was stimulated at the tail, it moved forward at a relatively fast speed and with high repeatability. The stimulator parameters were as follows: amplitude 1.85 μA, frequency 2 Hz, pulse duration 500 μs. Conclusions Since this is a preliminary study, considerable work remains to be done. However, the results could provide a solid theoretical basis for further research toward producing a practical intestinal bio-robot for the diagnosis and treatment of the gastrointestinal tract. PMID:23020999

  1. 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.

  2. 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.

  3. 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. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. 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

  5. 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

  6. Thermogenesis induced by osmotic stimulation of the intestines in the rat

    PubMed Central

    Osaka, Toshimasa; Kobayashi, Akiko; Inoue, Shuji

    2001-01-01

    Infusion of 5-20 % glucose, 1.8-3.6 % NaCl, 20 % methylglucose, 20 % fructose, or 5-10 % solutions of various amino acids (10 ml kg−1) into the duodenum induced dose-dependent thermogenesis in urethane-anaesthetized rats. In contrast, infusion of 0.9 % NaCl, distilled water, or safflower oil had no effect on the metabolic rate. Infusion of 7.2 % urea induced a small and transient increase in the metabolic rate. These results suggested that the thermogenesis was caused mainly by changes in osmolality rather than by a specific action of the different solute molecules. The respiratory exchange ratio increased after the infusion of glucose, fructose, glycine, or serine, did not change after the infusion of NaCl, methylglucose, safflower oil, or distilled water, and decreased after infusion of arginine. Therefore, there was no relationship between substrate utilization and the occurrence of thermogenesis. Intestinal infusion of 3.6 % NaCl elevated the plasma osmolality, with a plateau increase of ≈20 mosmol kg−1. However, intravenous infusion of the same amount of NaCl induced a significantly smaller thermogenic response, although it elevated the plasma osmolality with a time course and magnitude similar to those obtained after the intestinal infusion. Infusion of NaCl into the hepatic portal vein or the peritoneal cavity also produced a significantly small thermogenic response. These results suggested an intestinal or mesenteric location for osmoreceptors. To test for possible stimulation of intestinal osmoreceptors after intake of a normal meal, we measured the osmolality of the intestinal contents. The osmolality of the duodeno-jejunal contents was 600-800 mosmol kg−1, whereas the plasma osmolality was 306 ± 1 mosmol kg−1, which suggests that the intestinal osmoreceptors are stimulated after meals and are involved in diet-induced thermogenesis. PMID:11283240

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Activation of the Liver X Receptor Stimulates Trans-intestinal Excretion of Plasma Cholesterol*

    PubMed Central

    van der Veen, Jelske N.; van Dijk, Theo H.; Vrins, Carlos L. J.; van Meer, Hester; Havinga, Rick; Bijsterveld, Klaas; Tietge, Uwe J. F.; Groen, Albert K.; Kuipers, Folkert

    2009-01-01

    Recent studies have indicated that direct intestinal secretion of plasma cholesterol significantly contributes to fecal neutral sterol loss in mice. The physiological relevance of this novel route, which represents a part of the reverse cholesterol transport pathway, has not been directly established in vivo as yet. We have developed a method to quantify the fractional and absolute contributions of several cholesterol fluxes to total fecal neutral sterol loss in vivo in mice, by assessing the kinetics of orally and intravenously administered stable isotopically labeled cholesterol combined with an isotopic approach to assess the fate of de novo synthesized cholesterol. Our results show that trans-intestinal cholesterol excretion significantly contributes to removal of blood-derived free cholesterol in C57Bl6/J mice (33% of 231 μmol/kg/day) and that pharmacological activation of LXR with T0901317 strongly stimulates this pathway (63% of 706 μmol/kg/day). Trans-intestinal cholesterol excretion is impaired in mice lacking Abcg5 (−4%), suggesting that the cholesterol transporting Abcg5/Abcg8 heterodimer is involved in this pathway. Our data demonstrate that intestinal excretion represents a quantitatively important route for fecal removal of neutral sterols independent of biliary secretion in mice. This pathway is sensitive to pharmacological activation of the LXR system. These data support the concept that the intestine substantially contributes to reverse cholesterol transport. PMID:19416968

  13. Activation of AMPK Inhibits Cholera Toxin Stimulated Chloride Secretion in Human and Murine Intestine

    PubMed Central

    Hoekstra, Nadia; Collins, Danielle; Collaco, Anne; Baird, Alan W.; Winter, Desmond C.; Ameen, Nadia; Geibel, John P.; Kopic, Sascha

    2013-01-01

    Increased intestinal chloride secretion through chloride channels, such as the cystic fibrosis transmembrane conductance regulator (CFTR), is one of the major molecular mechanisms underlying enterotoxigenic diarrhea. It has been demonstrated in the past that the intracellular energy sensing kinase, the AMP-activated protein kinase (AMPK), can inhibit CFTR opening. We hypothesized that pharmacological activation of AMPK can abrogate the increased chloride flux through CFTR occurring during cholera toxin (CTX) mediated diarrhea. Chloride efflux was measured in isolated rat colonic crypts using real-time fluorescence imaging. AICAR and metformin were used to activate AMPK in the presence of the secretagogues CTX or forskolin (FSK). In order to substantiate our findings on the whole tissue level, short-circuit current (SCC) was monitored in human and murine colonic mucosa using Ussing chambers. Furthermore, fluid accumulation was measured in excised intestinal loops. CTX and forskolin (FSK) significantly increased chloride efflux in isolated colonic crypts. The increase in chloride efflux could be offset by using the AMPK activators AICAR and metformin. In human and mouse mucosal sheets, CTX and FSK increased SCC. AICAR and metformin inhibited the secretagogue induced rise in SCC, thereby confirming the findings made in isolated crypts. Moreover, AICAR decreased CTX stimulated fluid accumulation in excised intestinal segments. The present study suggests that pharmacological activation of AMPK effectively reduces CTX mediated increases in intestinal chloride secretion, which is a key factor for intestinal water accumulation. AMPK activators may therefore represent a supplemental treatment strategy for acute diarrheal illness. PMID:23935921

  14. 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.

  15. Vasoactive intestinal peptide prevents lung injury due to xanthine/xanthine oxidase.

    PubMed

    Berisha, H; Foda, H; Sakakibara, H; Trotz, M; Pakbaz, H; Said, S I

    1990-08-01

    Reactive oxygen species mediate injury and inflammation in many tissues. The addition of xanthine and xanthine oxidase to perfused rat lungs led to increases in peak airway pressure and perfusion pressure, pulmonary edema, and increased protein content in bronchoalveolar lavage fluid. Treatment with 1-10 micrograms.kg-1.min-1 of vasoactive intestinal peptide (VIP), a widely distributed neuropeptide, markedly reduced or totally prevented all signs of injury. Simultaneously, VIP also diminished or abolished the associated generation of arachidonate products. Similar protection was provided by catalase (100 micrograms/ml) but not by the VIP-related peptides secretin or glucagon. The pulmonary vasodilator papaverine (0.15 mg/ml) was also ineffective. Injured lungs that were not treated with VIP released large amounts of this peptide in the perfusate. The results indicate that VIP has potent protective activity against injury triggered by xanthine/xanthine oxidase and may be a physiological modulator of inflammatory tissue damage associated with toxic oxygen metabolites.

  16. Glucagon-like peptide-2 and mouse intestinal adaptation to a high-fat diet.

    PubMed

    Baldassano, Sara; Amato, Antonella; Cappello, Francesco; Rappa, Francesca; Mulè, Flavia

    2013-04-01

    Endogenous glucagon-like peptide-2 (GLP2) is a key mediator of refeeding-induced and resection-induced intestinal adaptive growth. This study investigated the potential role of GLP2 in mediating the mucosal responses to a chronic high-fat diet (HFD). In this view, the murine small intestine adaptive response to a HFD was analyzed and a possible involvement of endogenous GLP2 was verified using GLP2 (3-33) as GLP2 receptor (GLP2R) antagonist. In comparison with animals fed a standard diet, mice fed a HFD for 14 weeks exhibited an increase in crypt-villus mean height (duodenum, 27.5±3.0%; jejunum, 36.5±2.9%; P<0.01), in the cell number per villus (duodenum, 28.4±2.2%; jejunum, 32.0±2.9%; P<0.01), and in Ki67-positive cell number per crypt. No change in the percent of caspase-3-positive cell in the villus-crypt was observed. The chronic exposure to a HFD also caused a significant increase in GLP2 plasma levels and in GLP2R intestinal expression. Daily administration of GLP2 (3-33) (30-60  ng) for 4 weeks did not modify the crypt-villus height in control mice. In HFD-fed mice, chronic treatment with GLP2 (3-33) reduced the increase in crypt-villus height and in the cell number per villus through reduction of cell proliferation and increase in apoptosis. This study provides the first experimental evidence for a role of endogenous GLP2 in the intestinal adaptation to HFD in obese mice and for a dysregulation of the GLP2/GLP2R system after a prolonged HFD.

  17. 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.

  18. 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. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

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

    PubMed Central

    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

    2015-01-01

    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-EGFPLow) and reserve/facultative ISCs (Sox9-EGFPHigh) 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-EGFPLow ISCs and percentage of these cells in M-phase. IGF1 increased percentages of Sox9-EGFPHigh 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-EGFPHigh facultative ISCs but not Sox9-EGFPLow 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.—Van Landeghem, L., Santoro, M. A., Mah, A. T., Krebs, A. E., Dehmer, J. J., McNaughton, K. K., Helmrath, M. A., Magness, S. T., Lund, P. K. IGF1 stimulates crypt expansion via differential activation of 2 intestinal stem cell populations. PMID:25837582

  20. Potassium channel stimulation by natriuretic peptides through cGMP-dependent dephosphorylation.

    PubMed

    White, R E; Lee, A B; Shcherbatko, A D; Lincoln, T M; Schonbrunn, A; Armstrong, D L

    1993-01-21

    Natriuretic peptides inhibit the release and action of many hormones through cyclic guanosine monophosphate (cGMP), but the mechanism of cGMP action is unclear. In frog ventricular muscle and guinea-pig hippocampal neurons, cGMP inhibits voltage-activated Ca2+ currents by stimulating phosphodiesterase activity and reducing intracellular cyclic AMP; however, this mechanism is not involved in the action of cGMP on other channels or on Ca2+ channels in other cells. Natriuretic peptide receptors in the rat pituitary also stimulate guanylyl cyclase activity but inhibit secretion by increasing membrane conductance to potassium. In an electrophysiological study on rat pituitary tumour cells, we identified the large-conductance, calcium- and voltage-activated potassium channels (BK) as the primary target of another inhibitory neuropeptide, somatostatin. Here we report that atrial natriuretic peptide also stimulates BK channel activity in GH4C1 cells through protein dephosphorylation. Unlike somatostatin, however, the effect of atrial natriuretic peptide on BK channel activity is preceded by a rapid and potent stimulation of cGMP production and requires cGMP-dependent protein kinase activity. Protein phosphatase activation by cGMP-dependent kinase could explain the inhibitory effects of natriuretic peptides on electrical excitability and the antagonism of cGMP and cAMP in many systems.

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  4. 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.

  5. Clostridium difficile suppresses colonic vasoactive intestinal peptide associated with altered motility.

    PubMed

    Nassif, A; Longo, W E; Sexe, R; Stratton, M; Standeven, J; Vernava, A M; Kaminski, D L

    1995-01-01

    We investigated whether Clostridium difficile toxin alters colonic tissue levels of vasoactive intestinal peptide (VIP) at the expense of changes in colonic motility in the isolated perfused rabbit left colon. Colonic inflammation was induced by the intracolonic administration of 10(-8) M C. difflcile toxin. Strain gauge transducers were sewn onto the serosal surface of the colon to evaluate colonic motility. C. difflcile administration produced histologic changes consistent with epithelial damage. This was associated with an increased production of prostaglandin E(2) and thromboxane B(2). Tissue levels of VIP but not substance P were significantly reduced. This was associated with an increased number of contractions per minute and an average force of each colonic contraction. These results suggest that tissue levels of VIP are suppressed by C. difflcile and may participate in colonic dysmotility during active inflammation.

  6. Clostridium difficile suppresses colonic vasoactive intestinal peptide associated with altered motility

    PubMed Central

    Nassif, A.; Sexe, R.; Stratton, M.; Standeven, J.; Vernava, A. M.; Kaminski, D. L.

    1995-01-01

    We investigated whether Clostridium difficile toxin alters colonic tissue levels of vasoactive intestinal peptide (VIP) at the expense of changes in colonic motility in the isolated perfused rabbit left colon. Colonic inflammation was induced by the intracolonic administration of 10−8 M C. difflcile toxin. Strain gauge transducers were sewn onto the serosal surface of the colon to evaluate colonic motility. C. difflcile administration produced histologic changes consistent with epithelial damage. This was associated with an increased production of prostaglandin E2 and thromboxane B2. Tissue levels of VIP but not substance P were significantly reduced. This was associated with an increased number of contractions per minute and an average force of each colonic contraction. These results suggest that tissue levels of VIP are suppressed by C. difflcile and may participate in colonic dysmotility during active inflammation. PMID:18475679

  7. Increased egg production in juvenile turkey hens after active immunization with vasoactive intestinal peptide.

    PubMed

    Caldwell, S R; Johnson, A F; Yule, T D; Grimes, J L; Ficken, M; Christensen, V L

    1999-06-01

    Juvenile turkey hens were actively immunized against vasoactive intestinal peptide (VIP) prior to photostimulation to evaluate its effect on enhancing egg production. VIP antibody titers were generated in the VIP immunized hens and a greater rate of egg production per hen was observed compared to controls. In addition, the first egg laying cycle was extended for an additional 7 wk without a significant decline in egg production. Over a 27-wk period, 116 settable eggs per hen were produced from the VIP immunized hens as compared to 102 and 90 eggs for the keyhole limpet hemocyanin and saline control groups, respectively. Based on the increased egg production and the extension of the first egg laying cycle, this experiment demonstrates that VIP immunization of turkey hens is potentially economically relevant.

  8. Sacral nerve stimulation enhances early intestinal mucosal repair following mucosal injury in a pig model

    PubMed Central

    Brégeon, Jérémy; Coron, Emmanuel; Da Silva, Anna Christina Cordeiro; Jaulin, Julie; Aubert, Philippe; Chevalier, Julien; Vergnolle, Nathalie; Meurette, Guillaume

    2016-01-01

    Key points Reducing intestinal epithelial barrier (IEB) dysfunctions is recognized as being of major therapeutic interest for various intestinal disorders.Sacral nerve stimulation (SNS) is known to reduce IEB permeability.Here, we report in a pig model that SNS enhances morphological and functional recovery of IEB following mucosal injury induced via 2,4,6‐trinitrobenzenesulfonic acid. These effects are associated with an increased expression of tight junction proteins such as ZO‐1 and FAK.These results establish that SNS enhances intestinal barrier repair in acute mucosal injury. They further set the scientific basis for future use of SNS as a complementary or alternative therapeutic option for the treatment of gut disorders with IEB dysfunctions such as inflammatory bowel diseases or irritable bowel syndrome. Abstract Intestinal epithelial barrier (IEB) dysfunctions, such as increased permeability or altered healing, are central to intestinal disorders. Sacral nerve stimulation (SNS) is known to reduce IEB permeability, but its ability to modulate IEB repair remains unknown. This study aimed to characterize the impact of SNS on mucosal repair following 2,4,6‐trinitrobenzenesulfonic acid (TNBS)‐induced lesions. Six pigs were stimulated by SNS 3 h prior to and 3 h after TNBS enema, while sham animals (n = 8) were not stimulated. The impact of SNS on mucosal changes was evaluated by combining in vivo imaging, histological and functional methods. Biochemical and transcriptomic approaches were used to analyse the IEB and mucosal inflammatory response. We observed that SNS enhanced the recovery from TNBS‐induced increase in transcellular permeability. At 24 h, TNBS‐induced alterations of mucosal morphology were significantly less in SNS compared with sham animals. SNS reduced TNBS‐induced changes in ZO‐1 expression and its epithelial pericellular distribution, and also increased pFAK/FAK expression compared with sham. Interestingly, SNS increased

  9. Sacral nerve stimulation enhances early intestinal mucosal repair following mucosal injury in a pig model.

    PubMed

    Brégeon, Jérémy; Coron, Emmanuel; Da Silva, Anna Christina Cordeiro; Jaulin, Julie; Aubert, Philippe; Chevalier, Julien; Vergnolle, Nathalie; Meurette, Guillaume; Neunlist, Michel

    2016-08-01

    Reducing intestinal epithelial barrier (IEB) dysfunctions is recognized as being of major therapeutic interest for various intestinal disorders. Sacral nerve stimulation (SNS) is known to reduce IEB permeability. Here, we report in a pig model that SNS enhances morphological and functional recovery of IEB following mucosal injury induced via 2,4,6-trinitrobenzenesulfonic acid. These effects are associated with an increased expression of tight junction proteins such as ZO-1 and FAK. These results establish that SNS enhances intestinal barrier repair in acute mucosal injury. They further set the scientific basis for future use of SNS as a complementary or alternative therapeutic option for the treatment of gut disorders with IEB dysfunctions such as inflammatory bowel diseases or irritable bowel syndrome. Intestinal epithelial barrier (IEB) dysfunctions, such as increased permeability or altered healing, are central to intestinal disorders. Sacral nerve stimulation (SNS) is known to reduce IEB permeability, but its ability to modulate IEB repair remains unknown. This study aimed to characterize the impact of SNS on mucosal repair following 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced lesions. Six pigs were stimulated by SNS 3 h prior to and 3 h after TNBS enema, while sham animals (n = 8) were not stimulated. The impact of SNS on mucosal changes was evaluated by combining in vivo imaging, histological and functional methods. Biochemical and transcriptomic approaches were used to analyse the IEB and mucosal inflammatory response. We observed that SNS enhanced the recovery from TNBS-induced increase in transcellular permeability. At 24 h, TNBS-induced alterations of mucosal morphology were significantly less in SNS compared with sham animals. SNS reduced TNBS-induced changes in ZO-1 expression and its epithelial pericellular distribution, and also increased pFAK/FAK expression compared with sham. Interestingly, SNS increased the mucosal density of neutrophils

  10. 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

  11. 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

  12. Insulin stimulates transport of organic anion compounds mediated by organic anion transporting polypeptide 2B1 in the human intestinal cell line Caco-2.

    PubMed

    Kobayashi, Taku; Koizumi, Takahiro; Kobayashi, Masaki; Ogura, Jiro; Horiuchi, Yuichi; Kimura, Yuki; Kondo, Ayuko; Furugen, Ayako; Narumi, Katsuya; Takahashi, Natsuko; Iseki, Ken

    2017-04-01

    Organic anion transporting polypeptide 2B1 (OATP2B1) is the major uptake transporter in the intestine, and transports various clinically used therapeutic agents. Insulin acts through the insulin receptor in targeted cells, and Rab8A is one of the insulin signaling pathways. The small intestine in humans also expresses insulin receptor and Rab8A. It has been reported that insulin stimulates peptide transporter 1 (PEPT1) expression at the apical membrane and increases uptake of PEPT1 substrates in small intestine epithelial model cells (Caco-2 cells). However, the effect of insulin on OATP2B1 in the small intestine has not been fully investigated. We found that Rab8A was associated with OATP2B1-mediated estrone-3-sulfate (E3S) uptake. Insulin stimulated the uptake of E3S by Caco-2 cells and the enhancement was sustained for 120 min. The Vmax value of E3S uptake significantly increased upon insulin exposure. Caco-2 cells treated with insulin showed increased OATP2B1 expression at the cell surface. The apical-to-basal transport of E3S was also increased by insulin. The increase of E3S transport was inhibited by the cold condition (4 °C) or the OATP2B1 inhibitor, taurocholate. These results indicate that insulin acts on the small intestine to increase OATP2B1-mediated absorption. Copyright © 2016 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.

  13. 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.

  14. 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.

  15. Peptides having reduced toxicity that stimulate cholesterol efflux

    SciTech Connect

    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.

  16. Peptide YY antagonizes beta-adrenergic-stimulated release of insulin in dogs

    SciTech Connect

    Greeley, G.H. Jr.; Lluis, F.; Gomex, G.; Ishizuka, J.; Holland, B.; Thompson, J.C. )

    1988-04-01

    Peptide YY (PYY) and neuropeptide Y (NPY) are peptides of 36 amino acids that share structural homologies with pancreatic polypeptide (PP). PP is predominantly found in the endocrine pancreas. PYY is primarily found in mucosal endocrine cells of the distal ileum, colon, and rectum, whereas NPY is found in both the peripheral and central nervous system. Previous studies indicate that these peptides can interact with the autonomic nervous system. The objective of the present experiments was to study the effect of PYY on neurally stimulated insulin release in conscious dogs. Intravenous administration of PYY (100, 200, and 400 pmol{center dot}kg{sup {minus}1} {center dot}h{sup {minus}1}) reduced 2-DG-stimulated insulin release in a dose-dependent manner (P <0.05) without affecting plasma glucose levels. Administration of NPY, but not PP, reduced 2-DG-stimulated release of insulin. The inhibitory action of PYY on 2-DG-stimulated insulin release persisted in the presence of atropine or phentolamine treatment; however, hexamethonium alone or phentolamine plus propranolol treatment blocked the inhibitory action of PYY. Release of insulin stimulated by the {beta}-agonist isoproterenol was also inhibited by PYY. These results indicate that PYY can inhibit autonomic neurotransmission by a mechanism that may involve ganglionic or postganglionic inhibition of {beta}-adrenergic stimulation. The findings suggest a role for PYY and NPY in the autonomic regulation of insulin release.

  17. Intestinal Myofibroblasts Produce Nitric Oxide in Response to Combinatorial Cytokine Stimulation

    PubMed Central

    WU, JIANFENG; CHITAPANARUX, TANED; CHEN, YISHI; SOON, RUSSELL K.; YEE, HAL F.

    2014-01-01

    Inflammatory bowel disease (IBD) patients display elevated levels of intraluminal nitric oxide (NO). NO can react with other molecules to form toxic compounds, which has led to the idea that NO may be an important mediator of IBD. However, the cellular source of NO and how its production is regulated in the intestine are unclear. In this study we aimed to determine if intestinal myofibroblasts produce NO in response to the IBD-associated cytokines IL-1β, TNFα, and IFNγ. Intestinal myofibroblasts were isolated from mice and found to express inducible nitric oxide synthase (iNOS) mRNA, but not endothelial NOS or neuronal NOS. Individual treatment of myofibroblasts with IL-1β, TNFα, or IFNγ had no effect on NO production, but stimulation with combinations of these cytokines synergistically increased iNOS mRNA and protein expression. Treatment with TNFα or IFNγ increased cell surface expression of IFNγRI or TNFRII, respectively, suggesting that these cytokines act in concert to prime NO production by myofibroblasts. Impairment of NF-κB activity with a small molecule inhibitor was sufficient to prevent increased expression of IFNγRI or TNFRII, and inhibition of Akt, JAK/STAT, or NF-κB blocked nearly all NO production induced by combinatorial cytokine treatment. These data indicate that intestinal myofibroblasts require stimulation by multiple cytokines to produce NO and that these cytokines act through a novel pathway involving reciprocal cytokine receptor regulation and signaling by Akt, JAK/STAT, and NF-κB. PMID:22833357

  18. 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. © 2014 The Author(s).

  19. 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.

  20. Cytotoxicity of peptide-coated silver nanoparticles on the human intestinal cell line Caco-2.

    PubMed

    Böhmert, Linda; Niemann, Birgit; Thünemann, Andreas F; Lampen, Alfonso

    2012-07-01

    Silver nanoparticles are used in a wide range of consumer products such as clothing, cosmetics, household goods, articles of daily use and pesticides. Moreover, the use of a nanoscaled silver hydrosol has been requested in the European Union for even nutritional purposes. However, despite the wide applications of silver nanoparticles, there is a lack of information concerning their impact on human health. In order to investigate the effects of silver nanoparticles on human intestinal cells, we used the Caco-2 cell line and peptide-coated silver nanoparticles with defined colloidal, structural and interfacial properties. The particles display core diameter of 20 and 40 nm and were coated with the small peptide L-cysteine L-lysine L-lysine. Cell viability and proliferation were measured using Promegas CellTiter-Blue® Cell Viability assay, DAPI staining and impedance measurements. Apoptosis was determined by Annexin-V/7AAD staining and FACS analysis, membrane damage with Promegas LDH assay and reactive oxygen species by dichlorofluorescein assay. Exposure of proliferating Caco-2 cells to silver nanoparticle induced decreasing adherence capacity and cytotoxicity, whereby the formation of reactive oxygen species could be the mode of action. The effects were dependent on particle size (20, 40 nm), doses (5-100 μg/mL) and time of incubation (4-48 h). Apoptosis or membrane damage was not detected.

  1. 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

  2. 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.

  3. 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.

  4. Induction of alpha and beta chemokines by intestinal epithelial cells stimulated with Campylobacter jejuni.

    PubMed

    Bakhiet, Moiz; Al-Salloom, Fajer Subah; Qareiballa, Ahmed; Bindayna, Khalid; Farid, Iman; Botta, Giuseppe A

    2004-04-01

    To investigate the production of dynamic alpha and beta chemokines represented by interleukin-8 (IL-8) as alpha chemokine and CCL2 (monocyte-chemoattractant protein-1, CCR2 ligand), CCL4 (macrophage-inflammatory protein-1beta, CCR5 ligand), CCL3 (macrophage-inflammatory protein-1alpha, CCR1/5 ligand), (CCL5, regulated upon activation, normal T-cell expressed and secreted (RANTES, CCR5 ligand) as beta chemokines by the human intestinal cell line INT407 stimulated with factors produced by living Campylobacter jejuni (C. jejuni) and those present within sonicated and filtrated bacteria. We used immunohistochemical technique modified to detect intracellular production of cytokines protein and RT-PCR to read RNA messages for evaluation of de novo cytokine synthesis. Living bacteria induced increased numbers of IL-8, CCL4 and CCL2 but not CCL3 or CCL5 producing cells. Low numbers of IL-8, CCL4 and CCL2 producing cells were detected with filtrated supernatant compared to living and sonicated bacteria. A non-significant low number of chemokine producing cells was noted when comparing numbers of chemokine producing cells stimulated with living C. jejuni to those stimulated with sonicated bacteria, indicating that the triggering factors involved in stimulation with living bacteria were still active after sonication, but they were largely lost upon filtration. The mRNA signals for IL-8 were noted in conformity with its protein levels as increased IL-8 mRNA signals were registered after stimulation with living and sonicated bacteria but not with filtrated supernatant. Preferential production of chemokines probably induced by membrane associate factors of C. jejuni acting on intestinal epithelial cells is presented. These chemokines are suggested to be part of an inflammatory network affecting cell types that contribute to initiation and/or resolution of the infection.

  5. Comparison of the protective effect of self-emulsifying peptide drug delivery systems towards intestinal proteases and glutathione.

    PubMed

    Hetényi, Gergely; Griesser, Janine; Moser, Michael; Demarne, Frédéric; Jannin, Vincent; Bernkop-Schnürch, Andreas

    2017-05-15

    The aim of this study was to evaluate the protective effect of self-emulsifying drug delivery systems (SEDDS) for therapeutic peptides towards intestinal proteases and reduced glutathione (GSH). Sodium docusate was applied as anionic surfactant for hydrophobic ion pairing with leuprorelin (LEU), insulin (INS) and desmopressin (DES). The complexes were loaded into SEDDS that were characterized regarding droplet size distribution and zeta potential. The release profile of the peptides was examined by dialysis membrane method. Enzymatic digestion studies were performed by applying α-chymotrypsin, trypsin and elastase. Furthermore, the protective effect of SEDDS towards degradation through thiol-disulfide exchange reactions was examined by addition of GSH. SEDDS showed a mean droplet size of 0.27-3.9μm and a zeta potential of -25 to -33mV. All formulations provided a sustained release of the peptides over 6h. Degradation of the model peptides by intestinal proteases and GSH could only be observed in the release medium. In the oily phase of SEDDS neither any of the proteases nor GSH was soluble (≤0.1%). Furthermore, no degradation of the model peptides by proteases and GSH took place in the oily phase of SEDDS. SEDDS can provide a 100% protective effect towards protease degradation and deactivation by GSH. According to this, SEDDS might be promising tools for oral delivery of peptide drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. Neuritogenesis induced by vasoactive intestinal peptide, pituitary adenylate cyclase-activating polypeptide, and peptide histidine methionine in SH-SY5y cells is associated with regulated expression of cytoskeleton mRNAs and proteins.

    PubMed

    Héraud, Céline; Hilairet, Sandrine; Muller, Jean-Marc; Leterrier, Jean-François; Chadéneau, Corinne

    2004-02-01

    Vasoactive intestinal peptide (VIP) and the related peptides pituitary adenylate cyclase-activating polypeptide (PACAP) and peptide histidine methionine (PHM) are known to regulate proliferation and/or differentiation in normal and tumoral cells. In this study, neuritogenesis in human neuroblastoma SH-SY5Y cells cultured in serum-free medium was induced by VIP, PACAP, and PHM. The establishment of this process was followed by the quantification of neurite length and branching and the expression of neurofilament mRNAs, neurofilament proteins, and other cytoskeletal protein markers of neuronal differentiation: neuron-specific MAPs and beta-tubulin III. Neurite length and branching and the expression of most markers tested were increased by VIP and PACAP in a similar, although slightly different, fashion. In contrast, neuritic elongation induced by PHM was correlated with neither an increase in branching or neurofilament mRNAs nor a clear change in the expression of cytoskeleton proteins, with the exception of the stimulation by PHM of doublecortin, a microtubule-associated marker of migrating neuroblasts. These findings are the first evidence from a human neuron-like cell line for 1) a direct regulation of the metabolism of neurofilaments by VIP and PACAP and 2) the induction by PHM of neuritic processes of an apparent immature character. Copyright 2003 Wiley-Liss, Inc.

  14. 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.

  15. Vasoactive intestinal peptide reduces the inflammatory profile in mice infected with Trypanosoma cruzi.

    PubMed

    Higyno, Pulchéria Maria Silva; Mendes, Priscila Fagundes; Miranda, Marina Barcelos de; Pereira, Dario Elias; Mota, Ana Paula Lucas; Nogueira, Katiane de Oliveira Pinto Coelho; Caldas, Ivo Santana; Moura, Sandra Aparecida de Lima; Menezes, Cristiane Alves da Silva

    2015-12-01

    Vasoactive intestinal peptide (VIP) has gained great prominence because of its therapeutic potential, which is ascribed to its ability to regulate innate immunity, inhibit antigen-specific Th1 cell responses, and generate T regulatory cells. Additionally, VIP may act as a natural antimicrobial peptide, killing bacteria, fungi, and infective forms of Trypanosoma brucei. Despite the possible relevance of VIP during the course of Chagas disease, studies regarding this in human and experimental Trypanosoma cruzi infections remain poorly characterized. In this work, we evaluated the effects of VIP on systemic and cardiac immune responses during experimental acute infection. C57BL/6 mice were infected with 5000 trypomastigotes of the VL-10 strain of T. cruzi and treated with intraperitoneal VIP injection every other day for one month. After 30 days, we observed no reduction in parasitemia levels. However, we observed a reduction in serum levels of IFN-gamma and IL-2 and an increase in that of IL-4. These data suggest that VIP treatment modified immune responses to favor the Th2 response, which had no impact on parasitemia levels although the serum level of IFN-gamma was reduced. However, this change in immune balance reduced heart damage, as noted by the smaller cardiac volume and the moderate inflammatory infiltrate observed in VIP-treated mice. Our results indicate that VIP treatment reduced the inflammatory response at the cardiac site of mice that were experimentally infected with T. cruzi. These data suggest a protective role for VIP in the heart of infected mice. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Central Nervous System Regulation of Intestinal Lipoprotein Metabolism by Glucagon-Like Peptide-1 via a Brain-Gut Axis.

    PubMed

    Farr, Sarah; Baker, Christopher; Naples, Mark; Taher, Jennifer; Iqbal, Jahangir; Hussain, Mahmood; Adeli, Khosrow

    2015-05-01

    Intestinal overproduction of atherogenic chylomicron particles postprandially is an important component of diabetic dyslipidemia in insulin-resistant states. In addition to enhancing insulin secretion, peripheral glucagon-like peptide-1 (GLP-1) receptor stimulation has the added benefit of reducing this chylomicron overproduction in patients with type 2 diabetes mellitus. Given the presence of central GLP-1 receptors and GLP-1-producing neurons, we assessed whether central GLP-1 exerts an integral layer of neuronal control during the production of these potentially atherogenic particles. Postprandial production of triglyceride-rich lipoproteins was assessed in Syrian hamsters administered a single intracerebroventricular injection of the GLP-1 receptor agonist exendin-4. Intracerebroventricular exendin-4 reduced triglyceride-rich lipoprotein-triglyceride and -apolipoprotein B48 accumulation relative to vehicle-treated controls. This was mirrored by intracerebroventricular MK-0626, an inhibitor of endogenous GLP-1 degradation, and prevented by central exendin9-39, a GLP-1 receptor antagonist. The effects of intracerebroventricular exendin-4 were also lost during peripheral adrenergic receptor and central melanocortin-4 receptor inhibition, achieved using intravenous propranolol and phentolamine and intracerebroventricular HS014, respectively. However, central exendin9-39 did not preclude the effects of peripheral exendin-4 treatment on chylomicron output. Central GLP-1 is a novel regulator of chylomicron production via melanocortin-4 receptors. Our findings point to the relative importance of central accessibility of GLP-1-based therapies and compel further studies examining the status of this brain-gut axis in the development of diabetic dyslipidemia and chylomicron overproduction. © 2015 American Heart Association, Inc.

  17. Ventral tegmental self-stimulation selectively induces opioid peptide release in rat CNS.

    PubMed

    Stein, E A

    1993-01-01

    Intracranial self-stimulation (ICS) is thought to activate neuronal systems involved in processing natural reinforcing agents. Metabolic mapping studies have previously demonstrated a subset of CNS structures specifically engaged by ICS in animals receiving stimulation actively vs. passively. Since opiates are known to enhance ICS behavior and presumably its reinforcing properties, the current study addressed the question of the role of opioid peptides as mediators of ICS. Rats were trained on a fixed ration (FR) 20 schedule of responding maintained by ICS. Following response stabilization, rats were assigned either to an active or a corresponding yoked stimulation group at 1 of 2 schedules of reinforcement (i.e., FR1-YFR1, FR20-YFR20, or sedentary control), and opioid peptide release was inferred from in vivo receptor occupancy. Autoradiographic analyses identified 3 groups of structures. Treatment-induced alterations in occupancy were seen in the medial dorsal nucleus of the thalamus, basolateral amygdala, ventral pallidum, medial habenula, dorsal raphe, posterior hypothalamus, substantia nigra pars compacta, agranular preinsular cortex, and zona incerta. Depending upon the structure, peptide release was dependent upon stimulus contingency (active vs. yoked) and/or schedule (FR1 vs. FR20). Evidence for ICS-induced inhibition of peptide release was found in the habenula and preinsular cortex. Nine additional structures, all components of, or receiving projections from, the limbic system, revealed complex interactions between ICS treatment and the electrode side. Finally, a widespread ipsilateral increase in receptor binding was seen rostrally from the cingulate, olfactory tubercle, and nucleus accumbens, along the lateral hypothalamus and hippocampus, and extending caudally to the substantia nigra and ventral tegmentum. These later effects appear to be related to stimulation-induced changes in blood flow and subsequent ligant presentation increases. Collectively

  18. Metabolically Stabilized Long-Circulating PEGylated Polyacridine Peptide Polyplexes Mediate Hydrodynamically Stimulated Gene Expression in Liver

    PubMed Central

    Fernandez, Christian A.; Baumhover, Nicholas J.; Duskey, Jason T.; Khargharia, Sanjib; Kizzire, Koby; Ericson, Mark D.; Rice, Kevin G.

    2010-01-01

    A novel class of PEGylated polyacridine peptides was developed that mediate potent stimulated gene transfer in the liver of mice. Polyacridine peptides, (Acr-X)n-Cys-PEG, possessing 2–6 repeats of Lys-acridine (Acr) spaced by either Lys, Arg, Leu or Glu, were Cys derivatized with polyethylene glycol (PEG 5000 Da) and evaluated as in vivo gene transfer agents. An optimal peptide of (Acr-Lys)6-Cys-PEG was able to bind to plasmid DNA (pGL3) with high affinity by polyintercalation, stabilize DNA from metabolism by DNAse and extend the pharmacokinetic half-life of DNA in the circulation for up to 2 hrs. A tail vein dose of PEGylated polyacridine peptide pGL3 polyplexes (1 μg in 50 μl), followed by a stimulatory hydrodynamic dose of normal saline at times ranging from 5–60 min post-DNA administration, led to a high level of luciferase expression in the liver, equivalent to levels mediated by direct hydrodynamic dosing of 1 μg of pGL3. The results establish the unique properties of PEGylated polyacridine peptides as a new and promising class of gene delivery peptides that facilitate reversible binding to plasmid DNA, protecting it from DNase in vivo resulting in an extended circulatory half-life, and release of transfection-competent DNA into the liver to mediate a high-level of gene expression upon hydrodynamic boost. PMID:20720577

  19. A new relaxin-like gonad-stimulating peptide identified in the starfish Asterias amurensis.

    PubMed

    Mita, Masatoshi; Daiya, Misaki; Haraguchi, Shogo; Tsutsui, Kazuyoshi; Nagahama, Yoshitaka

    2015-10-01

    Relaxin-like gonad-stimulating peptide (RGP) of starfish Asterina pectinifera was the first invertebrate gonadotropin to have its chemical structure identified. However, it is unclear whether gonadotropic hormones in other species starfish are relaxin-like peptides. Thus, this study tried to identify the molecular structure of gonadotropic hormone in Asterias amurensis. As a result, we identified A. amurensis gonadotropic hormone as the RGP (AamRGP). The DNA sequence encoding AamRGP consisted of 330 base pairs with an open reading frame encoding a peptide of 109 amino acids (aa), including a signal peptide (26 aa), B-chain (20 aa), C-peptide (38 aa) and A-chain (25 aa). Comparing with A. pectinifera RGP (ApeRGP), the amino acid identity levels between AmaRGP and ApeRGP were 58% for the A-chain and 73% for the B-chain. Furthermore, chemical synthetic AamRGP induced gamete spawning and oocyte maturation in ovarian fragments of A. amurensis. In contrast, the ovary of A. pectinifera failed to respond to the AamRGP. This suggested that AamRGP is a new relaxin-like peptide. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Responses of peptide-specific T cells to stimulation with polystyrene beads carrying HLA class I molecules loaded with single peptides.

    PubMed

    Chersi, Alberto; Galati, Rossella; Accapezzato, Daniele; Francavilla, Vittorio; Barnaba, Vincenzo; Butler, Richard H; Tanigaki, Nobuyuki

    2004-08-01

    Cell-sized microbeads carrying single peptide-loaded HLA class I molecules were prepared for HLA-A2 and HLA-B7 by a simple procedure which transfers single peptide-loaded HLA class I molecules from cultured cells to polystyrene beads using anti-peptide antibodies directed to an intracellular segment of HLA-A alpha chains. The surface density of peptide-loaded HLA class I molecules on beads was comparable to that on the peptide-loaded cells. HLA-A2 beads loaded with an HCV peptide HCV1073 were tested for stimulation activity on an HCV1073-specific CD8+ T cell clone NS3-1. A substantial level of gamma-IFN production was induced. The stimulation was peptide-specific. The efficiency was dependent on the bead concentration and the surface HLA class I density on beads and enhanced significantly by co-coupling of anti-CD28 to peptide-loaded beads. The peptide-loading efficiency on HLA class I molecules and the transfer efficiency of HLA class I molecules to polystyrene beads were reasonably high for HLA-A2 and HLA-B7. Thus, polystyrene beads carrying these single peptide-loaded HLA class I molecules are potentially useful in further analysis of the co-stimulatory or inhibitory factors involved in CD8+ T cell responses and eventually in detection of cytotoxic T cells in PBLs.

  1. 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

  2. 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.

  3. Development of helix-based vasoactive intestinal peptide analogues: identification of residues required for receptor interaction.

    PubMed

    Musso, G F; Patthi, S; Ryskamp, T C; Provow, S; Kaiser, E T; Veliçelebi, G

    1988-10-18

    Several VIP analogues have been designed on the basis of the hypothesis that the region from residue 6 to residue 28 forms a pi-helical structure when bound to membrane receptors. An empirical approach for the design and construction of analogues based upon distribution frequency and structural homology with several sequence-related peptides is presented. Five peptides were designed, synthesized, and analyzed. One analogue, model 5, containing the native hydrophobic and an altered hydrophilic surface, was an effective VIP agonist in both binding to rat lung membrane receptors (KD1 = 11 +/- 8 pM, KD2 = 6.4 +/- 0.2 nM; VIP KD1 = 21 +/- 13 pM, KD2 = 1.8 +/- 0.6 nM) and stimulation of amylase release from guinea pig pancreatic acini (ED50 = 90 pM; VIP ED50 = 27 pM). The four other analogues were considerably less potent than VIP, yet retained full intrinsic activity. Our results showed that the hydrophobic surface of this helical domain (residues 6-28) contains amino acids important for interaction with receptors, whereas amino acid residues on the hydrophilic surface do not seem to participate strongly in receptor binding or signal transduction. Furthermore, on the basis of high-affinity binding, the stimulation of amylase release in pancreatic acini appears to be coupled to the higher affinity receptors. These results suggest that an approach based on the construction of putative pi-helical structures can be applied to the design of biologically active analogues of VIP. Thus, we have identified several residues within the VIP sequence that are critical for receptor binding using this approach.

  4. 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.

  5. 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

  6. Malignant pheochromocytoma secreting vasoactive intestinal peptide and response to sunitinib: a case report and literature review.

    PubMed

    Leibowitz-Amit, Raya; Lebowitz-Amit, Raya; Mete, Ozgur; Asa, Sylvia L; Ezzat, Shereen; Joshua, Anthony M

    2014-08-01

    Malignant pheochromocytoma is rare and may be sporadic or have a genetic basis. Vasoactive intestinal peptide (VIP)-secreting pheochromocytoma has rarely been described in the literature, and treatment remains challenging in the absence of well-controlled randomized trials. The hypoxia-inducible factor-vascular endothelial growth factor axis has been implicated in pheochromocytoma when associated with germline Von-Hippel-Lindau (VHL) or succinate dehydrogenase (SDH) mutations, suggesting potential clinical activity of sunitinib in this setting. We present a case report of a patient with a VIP-secreting malignant pheochromocytoma manifested as severe watery diarrhea, with an exquisite clinical response to sunitinib. We review this rare clinical entity and the potential role of sunitinib in this context. A 51-year-old male initially presented with a pheochromocytoma causing symptoms related to norepinephrine excess. He underwent adrenalectomy, which resulted in complete resolution of his symptoms. Three years later, he developed multifocal metastatic disease from his primary tumor, showing immunohistochemical evidence of VIP production accompanied by severe watery diarrhea and hypokalemia. The patient had a rapid, complete, and durable clinical response to sunitinib, but with only a minor radiological response and without significant toxicity. Genetic testing was negative for germline mutations in VHL, SDHB, SDHC, SDHD, transmembrane protein 127 (TMEM127) and for neurofibromatosis type 1 (NF-1). To the best of our knowledge, this is the first report of a case of malignant VIP-producing pheochromocytoma that was responsive to sunitinib.

  7. Vasoactive intestinal peptide receptor-based imaging and treatment of tumors (Review).

    PubMed

    Tang, Bo; Yong, Xin; Xie, Rui; Li, Qian-Wei; Yang, Shi-Ming

    2014-04-01

    Vasoactive intestinal peptide receptors (VIPRs) are members of the G-protein-coupled receptor superfamily. These receptors are overexpressed in many common malignant tumors and play a major role in the progression and angiogenesis of a number of malignancies. Therefore, VIPRs may be a valuable target for the molecular imaging of tumors and therapeutic interventions. The specific natural ligand or its analogs can be labeled with a radionuclide and used for tumor receptor imaging, which could be used to visualize VIPR-related surface protein expression in vivo and to monitor the in vivo effects of molecular drugs on tumors. Moreover, the involvement of VIPRs in malignant transformation and angiogenesis renders them potential therapeutic targets for cancer treatment. A variety of VIP antagonists and cytotoxic VIP conjugates have been synthesized and evaluated for VIPR-targeted molecular therapy. The importance of VIPRs in tumor biology and the ability to predict responses to targeted therapy and monitor drug interventions suggest that VIP receptor-based imaging and treatment will be critical for the early diagnosis and management of cancer. Here, we review the current literature regarding VIPRs and their natural ligands and the involvement of VIPRs in tumor growth and angiogenesis, with an emphasis on the present use of VIPRs for the molecular imaging of tumors and therapies targeting VIPRs.

  8. 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.

  9. 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.

  10. Vasoactive intestinal peptide can promote the development of neonatal rat primordial follicles during in vitro culture.

    PubMed

    Chen, Niannian; Li, Yu; Wang, Wenjun; Ma, Yun; Yang, Dongzi; Zhang, Qingxue

    2013-01-01

    Recruitment of primordial follicles is essential for female fertility. Some of the intraovarian growth factors involved in the initiation of primordial follicle growth have been identified, but the exact mechanisms regulating follicle activation are poorly understood. Strong evidence indicates that vasoactive intestinal peptide (VIP), a neuropeptide found in ovarian nerves, plays a role in the physiology of follicle development and function. The aim of the present study was to determine whether VIP might regulate the activation and growth of neonatal rat primordial follicles in an in vitro culture system. Ovaries from 4-day-old rats were cultured for 14 days in medium containing 10(-7) M VIP. At the end of the culture, the developmental stages and viability of the follicles were evaluated using histological sections. Immunohistochemistry studies for proliferating cell nuclear antigen (PCNA) were performed to assess the mitotic activity of granulosa cells. In addition, the expression level of kit ligand (KL) mRNA was examined after culture. Histology showed that primordial follicles could survive and start to grow in vitro. The proportion of primordial follicles was decreased and the proportion of early primary follicles increased after in vitro culture with VIP. Immunolocalization of PCNA showed that follicle growth was initiated after VIP treatment. The expression level of KL mRNA was increased in the VIP treatment group. Thus, VIP can promote primordial follicle development, possibly mediated in part through upregulating the expression of KL.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Sweet taste receptors in rat small intestine stimulate glucose absorption through apical GLUT2

    PubMed Central

    Mace, Oliver J; Affleck, Julie; Patel, Nick; Kellett, George L

    2007-01-01

    Natural sugars and artificial sweeteners are sensed by receptors in taste buds. T2R bitter and T1R sweet taste receptors are coupled through G-proteins, α-gustducin and transducin, to activate phospholipase C β2 and increase intracellular calcium concentration. Intestinal brush cells or solitary chemosensory cells (SCCs) have a structure similar to lingual taste cells and strongly express α-gustducin. It has therefore been suggested over the last decade that brush cells may participate in sugar sensing by a mechanism analogous to that in taste buds. We provide here functional evidence for an intestinal sensing system based on lingual taste receptors. Western blotting and immunocytochemistry revealed that all T1R members are expressed in rat jejunum at strategic locations including Paneth cells, SCCs or the apical membrane of enterocytes; T1Rs are colocalized with each other and with α-gustducin, transducin or phospholipase C β2 to different extents. Intestinal glucose absorption consists of two components: one is classical active Na+–glucose cotransport, the other is the diffusive apical GLUT2 pathway. Artificial sweeteners increase glucose absorption in the order acesulfame potassium ∼ sucralose > saccharin, in parallel with their ability to increase intracellular calcium concentration. Stimulation occurs within minutes by an increase in apical GLUT2, which correlates with reciprocal regulation of T1R2, T1R3 and α-gustducin versus T1R1, transducin and phospholipase C β2. Our observation that artificial sweeteners are nutritionally active, because they can signal to a functional taste reception system to increase sugar absorption during a meal, has wide implications for nutrient sensing and nutrition in the treatment of obesity and diabetes. PMID:17495045

  17. A relaxin-like gonad-stimulating peptide from the starfish Aphelasterias japonica.

    PubMed

    Mita, Masatoshi; Katayama, Hidekazu

    2016-04-01

    Relaxin-like gonad-stimulating peptide (RGP) in starfish is the first identified invertebrate gonadotropin responsible for final gamete maturation. In this study, a new ortholog RGP was identified from Aphelasterias japonica. The DNA sequence encoding A. japonica RGP (AjaRGP) consists of 342 base pairs with an open reading frame encoding a peptide of 113 amino acids (aa), including a signal peptide (26aa), B-chain (20aa), C-peptide (42aa), and A-chain (25aa). AjaRGP is a heterodimeric peptide with disulfide cross-linkages. Comparing with Asterias amurensis RGP (AamRGP) and Patiria (=Asterina) pectinifera RGP (PpeRGP), the amino acid identity levels of AjaRGP with respect to AamRGP and PpeRGP are 84% and 58% for the A-chain and 90% and 68% for the B-chain, respectively. This suggests that AjaRGP is closer to AmaRGP rather than PpeRGP. Although chemical synthetic AjaRGP can induce gamete spawning and oocyte maturation in ovarian fragments of A. japonica, the ovary of P. pectinifera fails to respond to AjaRGP. This suggests that AjaRGP acts species-specifically. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Butyrate stimulates the growth of human intestinal smooth muscle cells by activation of Yes-Associated Protein.

    PubMed

    Dai, Li-Na; Yan, Jun-Kai; Xiao, Yong-Tao; Wen, Jie; Zhang, Tian; Zhou, Ke-Jun; Wang, Yang; Cai, Wei

    2017-08-23

    Intestinal smooth muscle cells play a critical role in the remodeling of intestinal structure and functional adaptation after bowel resection. Recent studies have shown that supplementation of butyrate (Bu) contributes to the compensatory expansion of a muscular layer of the residual intestine in a rodent model of short-bowel syndrome (SBS). However, the underlying mechanism remains elusive. In this study, we found that the growth of human intestinal smooth muscle cells (HISMCs) was significantly stimulated by Bu via activation of Yes-Associated Protein (YAP). Incubation with 0.5 mM Bu induced a distinct proliferative effect on HISMCs, as indicated by the promotion of cell cycle progression and increased DNA replication. Notably, YAP silencing by RNA interference or its specific inhibitor significantly abolished the proliferative effect of Bu on HISMCs. Furthermore, Bu induced YAP expression and enhanced the translocation of YAP from the cytoplasm to the nucleus, which led to changes in the expression of mitogenesis genes, including TEAD1, TEAD4, CTGF and Cyr61. These results provide evidence that Bu stimulates the growth of human intestinal muscle cells by activation of YAP, which may be a potential treatment for improving intestinal adaptation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  19. Oral administration of Lactococcus lactis-expressed recombinant porcine epidermal growth factor stimulates the development and promotes the health of small intestines in early-weaned piglets.

    PubMed

    Xu, S; Wang, D; Zhang, P; Lin, Y; Fang, Z; Che, L; Wu, D

    2015-07-01

    We previously generated Lactococcus lactis-expressed recombinant porcine epidermal growth factor (LL-pEGF), and demonstrated improved growth performance in early-weaned piglets. This study investigates the effect of LL-pEGF on the development and expression of genes that maintain the structural integrity and function of the small intestine in early-weaned piglets. The mitogenic effect of porcine epidermal growth factor (pEGF) was tested in vitro with the 5-Bromodeoxyuridine (BrdU) incorporation assay in fibroblast cells. In the in vivo study, 40 weaned piglets were randomly allocated to control, antibiotic control, Lc. lactis-expressing empty vector (LL-EV) and LL-pEGF treatment groups. Cells treated with LL-pEGF had higher BrdU-positive stained cells than those in the control and the LL-EV treatments (P < 0·05). Scanning electron microscope and histological examination demonstrated that the small intestinal villi treated with LL-pEGF were higher (P < 0·05) than in the other treatments. LL-pEGF increased the messenger RNA (mRNA) expression levels of the intestinal structural integrity proteins trefoil factor 3, claudin 1 (CLDN1), occludin and zonula occludens 1 (ZO-1), the digestive enzymes sucrose, aminopeptidase A, and aminopeptidase N, and the nutrient transporters sodium/glucose cotransporter 1 (SGLT1), glucose transporter 2, and peptide transporter 1 (PEPT1) as compared with the control (P < 0·05) in the small intestine. Meanwhile, the mRNA levels of CLDN1 in the jejunum and ZO-1 in the ileum were higher in the LL-EV group than in the control group (P < 0·05). LL-EV and the antibiotic control increased SGLT1 mRNA in the jejunum and PEPT1 mRNA in the ileum compared with the control (P < 0·05). Recombinant pEGF promotes cell mitosis. Oral administration of Lc. lactis-expressing pEGF stimulated intestinal development by upregulating the gene expression of the intestinal structural integrity proteins, the digestive enzymes and the nutrient transporters. The

  20. 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.

  1. 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

  2. Multi- and single-fibre mesenteric and renal sympathetic responses to chemical stimulation of intestinal receptors in cats.

    PubMed Central

    Stein, R D; Weaver, L C

    1988-01-01

    1. In cats anaesthetized with alpha-chloralose and artificially respired, stimulation of intestinal receptors with bradykinin caused greater reflex excitation of mesenteric than of renal efferent multifibre nerve activity and significant pressor responses. 2. Activity of all nerve bundles used in this study was inhibited by stimulation of pressoreceptors. Increases in systemic arterial pressure caused inhibition of activity of renal nerves which was significantly greater than that of mesenteric nerves. 3. Spinal transection caused significant decreases in tonic renal nerve activity without altering the ongoing discharge rate of mesenteric nerves. Stimulation of intestinal receptors in spinal cats still caused significant increases is discharge of mesenteric and renal nerves, indicating that this reflex contains a spinal component. 4. Recordings of activity of individual fibres within mesenteric (21) and renal (23) nerves provided information regarding the basis for the multifibre responses to stimulation of intestinal receptors. The same proportion of fibres from both nerves was excited, but the increase in activity of mesenteric fibres was significantly greater than that of renal fibres. 5. Mesenteric fibres could be classified into two groups, based on their sensitivity to pressoreceptor influences. Fibres that exhibited pressoreceptor-independent discharge had the greatest responses to stimulation of intestinal receptors. 6. Following spinal transection the majority of mesenteric fibres continued to fire, whereas most renal fibres became quiescent. 7. The non-uniform pattern of neuronal excitation to chemical stimulation of intestinal receptors was manifest after spinal transection, demonstrating that exclusively spinal pathways can mediate this differential response pattern. 8. These results support the hypothesis that viscero-sympathetic reflexes may be organized to cause preferential excitation of neural activity directed to the organ from which the reflex

  3. 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

  4. 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

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

    USDA-ARS?s Scientific Manuscript database

    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...

  6. Deficiency in macrophage-stimulating protein results in spontaneous intestinal inflammation and increased susceptibility toward epithelial damage in zebrafish.

    PubMed

    Witte, Merlijn; Huitema, Leonie F A; Nieuwenhuis, Edward E S; Brugman, Sylvia

    2014-12-01

    Several genome-wide association studies have identified the genes encoding for macrophage-stimulating protein (MSP) and its receptor RON (Recepteur d'Origine Nantais) as possible susceptibility factors in inflammatory bowel disease. While it has been shown that the MSP-RON signaling pathway is involved in tissue injury responses, current mouse models for MSP and RON deficiency have not clearly demonstrated a role of MSP-RON signaling in the context of intestinal inflammation. In this study, we report that the recently identified zebrafish Msp mutant (msp(t34230)) develops spontaneous intestinal inflammation over time. From 14 to 28 weeks postfertilization Msp-deficient zebrafish show intestinal eosinophilia, increased intestinal expression of inflammatory marker mmp9, and activation of intestinal goblet cells. Moreover, these Msp mutant zebrafish are more susceptible toward ethanol-induced epithelial damage, which resulted in increased infiltration and proliferation of immune cells within the lamina propria and prolonged intestinal proinflammatory cytokine responses in some mutant fish. In light of the recent development of many tools to visualize, monitor, and genetically modify zebrafish, these Msp-deficient zebrafish will enable in-depth in vivo analysis of epithelial and macrophage-specific MSP-RON signaling in the context of intestinal inflammation.

  7. 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. Copyright © 2014 the American Physiological Society.

  8. The effects of individualized gastric electrical stimulation on food craving and gastrointestinal peptides in dogs.

    PubMed

    Guo, Xiaojuan; Li, Yanmei; Yao, Shukun; Chen, Shaoxuan; Du, Yuhui; Wang, Zhihua

    2014-07-01

    Using an adjustable stimulator with a wide range of stimulation parameters, the aims of this study were 1) to investigate the effects of long-term gastric electrical stimulation (GES) on appetite and differential food cravings for three different foods and 2) to investigate the effects of GES on plasma gastrointestinal peptide concentrations. The study was performed in eight Beagle dogs implanted with one pair of serosal electrodes. They were followed during GES and sham GES sessions in a crossover design. GES was conducted using a series of individualized parameters. Food intake and food cravings were observed to evaluate the effects of long-term GES. Enzyme-linked immunosorbent assay was used to measure the plasma concentrations of gastrointestinal peptides. Dogs on GES for three months ate significantly less food than those on sham GES for three months (p < 0.05). A significant change in food cravings was induced by GES. Dogs with GES ate significantly less high-fat food. However, there was no significant difference in consumption of high-carbohydrate food or balanced food between the periods of GES and sham GES. The plasma concentrations of ghrelin, peptide YY3-36, and glucagon-like peptide 1 did not differ significantly between the periods of GES and sham GES. Food intake and food craving were changed significantly by adjustable GES. GES may be used for treating obesity by changing food preferences. Further clinical studies are necessary to highlight the effect of adjustable GES on eating behavior. © 2014 International Neuromodulation Society.

  9. 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

  10. Cytoprotective effect of neuropeptides on cancer stem cells: vasoactive intestinal peptide-induced antiapoptotic signaling.

    PubMed

    Sastry, Konduru S; Chouchane, Aouatef Ismail; Wang, Ena; Kulik, George; Marincola, Francesco M; Chouchane, Lotfi

    2017-06-01

    Cancer stem cells (CSCs) are increasingly considered to be responsible for tumor initiation, metastasis and drug resistance. The drug resistance mechanisms activated in CSCs have not been thoroughly investigated. Although neuropeptides such as vasoactive intestinal peptide (VIP) can promote tumor growth and activate antiapoptotic signaling in differentiated cancer cells, it is not known whether they can activate antiapoptotic mechanisms in CSCs. The objectives of this study are to unravel the cytoprotective effects of neuropeptides and identify antiapoptotic mechanisms activated by neuropeptides in response to anticancer drug treatment in CSCs. We enriched and purified CSCs (CD44(+/high)/CD24(-/low) or CD133(+) population) from breast and prostate cancer cell lines, and demonstrated their stemness phenotype. Of the several neuropeptides tested, only VIP could protect CSCs from drug-induced apoptosis. A functional correlation was found between drug-induced apoptosis and dephosphorylation of proapoptotic Bcl2 family protein BAD. Similarly, VIP-induced cytoprotection correlated with BAD phosphorylation at Ser112 in CSCs. Using pharmacological inhibitors and dominant-negative proteins, we showed that VIP-induced cytoprotection and BAD phosphorylation are mediated via both Ras/MAPK and PKA pathways in CSCs of prostate cancer LNCaP and C4-2 cells, but only PKA signaling was involved in CSCs of DUVIPR (DU145 prostate cancer cells ectopically expressing VIP receptor) and breast cancer MCF7 cells. As each of these pathways partially control BAD phosphorylation at Ser112, both have to be inhibited to block the cytoprotective effects of VIP. Furthermore, VIP is unable to protect CSCs that express phosphorylation-deficient mutant-BAD, suggesting that BAD phosphorylation is essential. Thus, antiapoptotic signaling by VIP could be one of the drug resistance mechanisms by which CSCs escape from anticancer therapies. Our findings suggest the potential usefulness of VIP receptor

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  17. 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.

  18. 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

  19. 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

  20. Vago–sympathoadrenal reflex in thermogenesis induced by osmotic stimulation of the intestines in the rat

    PubMed Central

    Osaka, Toshimasa; Kobayashi, Akiko; Inoue, Shuji

    2002-01-01

    Duodenal infusion of hypertonic solutions elicits osmolality-dependent thermogenesis in urethane-anaesthetized rats. Here we investigated the involvement of the autonomic nervous system, adrenal medulla and brain in the mechanism of this thermogenesis. Bilateral subdiaphragmatic vagotomy greatly attenuated the first hour, but not the later phase, of the thermogenesis induced by 3.6 % NaCl (10 ml kg−1). Neither atropine pretreatment (10 mg kg−1, i.p) nor capsaicin desensitization had any effect on the osmotically induced thermogenesis, suggesting the involvement of non-nociceptive vagal afferents. Bilateral splanchnic denervation caudal to the suprarenal ganglia also had no effect, suggesting a lack of involvement of spinal afferents and sympathetic efferents to the major upper abdominal organs. Adrenal demedullation greatly attenuated the initial phase, but not the later phase, of thermogenesis. Pretreatment with the β-blocker propranolol (20 mg kg−1, i.p) attenuated the thermogenesis throughout the 3 h observation period. The plasma adrenaline concentration increased significantly 20 min after osmotic stimulation but returned to the basal level after 60 min. The plasma noradrenaline concentration increased 20 min after osmotic stimulation and remained significantly elevated for 120 min. Therefore, adrenaline largely mediated the initial phase of thermogenesis, and noradrenaline was involved in the entire thermogenic response. Moreover, neither decerebration nor pretreatment with the antipyretic indomethacin (10 mg kg−1, s.c) had any effect. Accordingly, this thermogenesis did not require the forebrain and was different from that associated with fever. These results show the critical involvement of the vagal afferents, hindbrain and sympathoadrenal system in the thermogenesis induced by osmotic stimulation of the intestines. PMID:11956352

  1. 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.

  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. 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

  5. Probiotics stimulate enterocyte migration and microbial diversity in the neonatal mouse intestine

    PubMed Central

    Preidis, Geoffrey A.; Saulnier, Delphine M.; Blutt, Sarah E.; Mistretta, Toni-Ann; Riehle, Kevin P.; Major, Angela M.; Venable, Susan F.; Finegold, Milton J.; Petrosino, Joseph F.; Conner, Margaret E.; Versalovic, James

    2012-01-01

    Beneficial microbes and probiotics show promise for the treatment of pediatric gastrointestinal diseases. However, basic mechanisms of probiosis are not well understood, and most investigations have been performed in germ-free or microbiome-depleted animals. We sought to functionally characterize probiotic-host interactions in the context of normal early development. Outbred CD1 neonatal mice were orally gavaged with one of two strains of human-derived Lactobacillus reuteri or an equal volume of vehicle. Transcriptome analysis was performed on enterocyte RNA isolated by laser-capture microdissection. Enterocyte migration and proliferation were assessed by labeling cells with 5-bromo-2′-deoxyuridine, and fecal microbial community composition was determined by 16S metagenomic sequencing. Probiotic ingestion altered gene expression in multiple canonical pathways involving cell motility. L. reuteri strain DSM 17938 dramatically increased enterocyte migration (3-fold), proliferation (34%), and crypt height (29%) compared to vehicle-treated mice, whereas strain ATCC PTA 6475 increased cell migration (2-fold) without affecting crypt proliferative activity. In addition, both probiotic strains increased the phylogenetic diversity and evenness between taxa of the fecal microbiome 24 h after a single probiotic gavage. These experiments identify two targets of probiosis in early development, the intestinal epithelium and the gut microbiome, and suggest novel mechanisms for probiotic strain-specific effects.—Preidis, G. A., Saulnier, D. M., Blutt, S. E., Mistretta,T.-A., Riehle, K. P., Major, A. M., Venable, S. F., Finegold, M. J., Petrosino, J. F., Conner, M. E., Versalovic, J. Probiotics stimulate enterocyte migration and microbial diversity in the neonatal mouse intestine. PMID:22267340

  6. 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.

  7. Simultaneous stimulation of glycolysis and gluconeogenesis by feeding in the anterior intestine of the omnivorous GIFT tilapia, Oreochromis niloticus.

    PubMed

    Chen, Yong-Jun; Zhang, Ti-Yin; Chen, Hai-Yan; Lin, Shi-Mei; Luo, Li; Wang, De-Shou

    2017-06-15

    The present study was performed to investigate the roles of anterior intestine in the postprandial glucose homeostasis of the omnivorous Genetically Improved Farmed Tilapia (GIFT). Sub-adult fish (about 173 g) were sampled at 0, 1, 3, 8 and 24 h post feeding (HPF) after 36 h of food deprivation, and the time course of changes in intestinal glucose transport, glycolysis, glycogenesis and gluconeogenesis at the transcription and enzyme activity level, as well as plasma glucose contents, were analyzed. Compared with 0 HPF (fasting for 36 h), the mRNA levels of both ATP-dependent sodium/glucose cotransporter 1 and facilitated glucose transporter 2 increased during 1-3 HPF, decreased at 8 HPF and then leveled off. These results indicated that intestinal uptake of glucose and its transport across the intestine to blood mainly occurred during 1-3 HPF, which subsequently resulted in the increase of plasma glucose level at the same time. Intestinal glycolysis was stimulated during 1-3 HPF, while glucose storage as glycogen was induced during 3-8 HPF. Unexpectedly, intestinal gluconeogenesis (IGNG) was also strongly induced during 1-3 HPF at the state of nutrient assimilation. The mRNA abundance and enzyme activities of glutamic-pyruvic and glutamic-oxaloacetic transaminases increased during 1-3 HPF, suggesting that the precursors of IGNG might originate from some amino acids. Taken together, it was concluded that the anterior intestine played an important role in the regulation of postprandial glucose homeostasis in omnivorous tilapia, as it represented significant glycolytic potential and glucose storage. It was interesting that postprandial IGNG was stimulated by feeding temporarily, and its biological significance remains to be elucidated in fish. © 2017. Published by The Company of Biologists Ltd.

  8. 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).

  9. 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.

  10. 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

  11. Vasoactive intestinal peptide downregulates proinflammatory TLRs while upregulating anti-inflammatory TLRs in the infected cornea.

    PubMed

    Jiang, Xiaoyu; McClellan, Sharon A; Barrett, Ronald P; Zhang, Yunfan; Hazlett, Linda D

    2012-07-01

    TLRs recognize microbial pathogens and trigger an immune response, but their regulation by neuropeptides, such as vasoactive intestinal peptide (VIP), during Pseudomonas aeruginosa corneal infection remains unexplored. Therefore, C57BL/6 (B6) mice were injected i.p. with VIP, and mRNA, protein, and immunostaining assays were performed. After VIP treatment, PCR array and real-time RT-PCR demonstrated that proinflammatory TLRs (conserved helix-loop-helix ubiquitous kinase, IRAK1, TLR1, TLR4, TLR6, TLR8, TLR9, and TNFR-associated factor 6) were downregulated, whereas anti-inflammatory TLRs (single Ig IL-1-related receptor [SIGIRR] and ST2) were upregulated. ELISA showed that VIP modestly downregulated phosphorylated inhibitor of NF-κB kinase subunit α but upregulated ST2 ~2-fold. SIGIRR was also upregulated, whereas TLR4 immunostaining was reduced in cornea; all confirmed the mRNA data. To determine whether VIP effects were cAMP dependent, mice were injected with small interfering RNA for type 7 adenylate cyclase (AC7), with or without VIP treatment. After silencing AC7, changes in mRNA levels of TLR1, TNFR-associated factor 6, and ST2 were seen and unchanged with addition of VIP, indicating that their regulation was cAMP dependent. In contrast, changes were seen in mRNA levels of conserved helix-loop-helix ubiquitous kinase, IRAK1, 2, TLR4, 9 and SIGIRR following AC7 silencing alone; these were modified by VIP addition, indicating their cAMP independence. In vitro studies assessed the effects of VIP on TLR regulation in macrophages and Langerhans cells. VIP downregulated mRNA expression of proinflammatory TLRs while upregulating anti-inflammatory TLRs in both cell types. Collectively, the data provide evidence that VIP downregulates proinflammatory TLRs and upregulates anti-inflammatory TLRs and that this regulation is both cAMP dependent and independent and involves immune cell types found in the infected cornea.

  12. 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.

  13. 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.

  14. 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.

  15. Homologous HSV1 and alpha-synuclein peptides stimulate a T cell response in Parkinson's disease.

    PubMed

    Caggiu, E; Paulus, K; Galleri, G; Arru, G; Manetti, R; Sechi, G P; Sechi, L A

    2017-09-15

    Environmental factors are implicated in the development of Parkinson's disease (PD). The aim of this study is to investigate the role of cell-mediated immunity upon a specific immune-stimulation with HSV-1 and human alpha-synuclein homologues peptides by using the intracellular cytokine method on Parkinson's patients and healthy controls. The study showed, for the first time, a specific response to TNF-α CD8, CD4 and NK cells after stimulation in PD patients. Our data show a possible role of the immune system in the pathogenesis of Parkinson's disease, and that HSV-1 infections may lead to a progression of the disease. Copyright © 2017. Published by Elsevier B.V.

  16. 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.

  17. Histone H4-related osteogenic growth peptide (OGP): a novel circulating stimulator of osteoblastic activity.

    PubMed Central

    Bab, I; Gazit, D; Chorev, M; Muhlrad, A; Shteyer, A; Greenberg, Z; Namdar, M; Kahn, A

    1992-01-01

    It has been established that regenerating marrow induces an osteogenic response in distant skeletal sites and that this activity is mediated by factors released into the circulation by the healing tissue. In the present study we have characterized one of these factors, a 14 amino acid peptide named osteogenic growth peptide (OGP). Synthetic OGP, identical in structure to the native molecule, stimulates the proliferation and alkaline phosphatase activity of osteoblastic cells in vitro and increases bone mass in rats when injected in vivo. Immunoreactive OGP in high abundance is present physiologically in the serum, mainly in the form of an OGP-OGP binding protein complex. A marked increase in serum bound and unbound OGP accompanies the osteogenic phase of post-ablation marrow regeneration and associated systemic osteogenic response. Authentic OGP is identical to the C-terminus of histone H4 and shares a five residue motif with a T-cell receptor beta-chain V-region and the Bacillus subtilis outB locus. Since these latter proteins have not been implicated previously in the control of cell proliferation or differentiation, OGP may belong to a novel, heretofore unrecognized family of regulatory peptides. Perhaps more importantly, OGP appears to represent a new class of molecules involved in the systemic control of osteoblast proliferation and differentiation. Images PMID:1582415

  18. THE BIOSYNTHESIS, INTRACELLULAR TRANSPORT, AND PACKAGING OF MELANOCYTE-STIMULATING PEPTIDES IN THE AMPHIBIAN PARS INTERMEDIA

    PubMed Central

    Hopkins, C. R.

    1972-01-01

    Experiments in which glycine-3H has been introduced into excised neurointermediate lobes of Xenopus laevis incubated in a modified Krebs-Ringer bicarbonate medium have shown that ∼ 50% of the incorporated radioactivity is present in small peptides which have an electrophoretic mobility characteristic of the melanocyte-stimulating (MSH) peptides shown to be elaborated within the tissue. Based on these results and the demonstration that a discrete ∼ 7 min pulse of the label can be introduced into the tissue, electron microscope radioautography has been employed to follow the subcellular events concerned with the synthesis, intracellular transport, and packaging of the labeled secretory product. Together, these studies indicate that the newly synthesized material arises in peptide form, rather than as part of a larger prohormone molecule, on the ribosomes of the rough endoplasmic reticulum within the parenchymal cells of the intermediate portion of the lobe. A proportion is then incorporated into and remains for an extended period within the intracisternal granules which are a feature of the rough endoplasmic reticulum within these cells in vitro Most (∼ 60%) of the labeled secretory product, however, is transferred to the Golgi complex within 30 min and, within a further 10 min, becomes packaged into small (∼ 200 mµ) electron-opaque secretory granules. It is probable that under the conditions employed these granules represent the final intracellular location of secretory product before it is released PMID:5028257

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Pulse Width-Dependent Effects of Intestinal Electrical Stimulation for Obesity: Role of Gastrointestinal Motility and Hormones.

    PubMed

    Li, Shiying; Chen, Jiande D Z

    2017-01-01

    The goals of this experiment were to study therapeutic potential of intestinal electrical stimulation (IES) for obesity, its mechanisms involving gastrointestinal motility and hormones, and role of pulse width in diet-induced obese rats. In a 4-week study, rats equipped with one pair of electrodes at the duodenum were assigned to receive either a sham or IES of varied pulse widths in a sequential way. Food intake was measured daily and body weight measured weekly. Blood samples were collected for the measurement of glucagon-like peptide-1 (GLP-1). Solid gastric emptying (GE) and small bowel transit (SIT) tests were performed at the end of the experiment. The results of the study were as follows: (1) Daily food intake, not affected by IES of 0.3 ms, was pulse width-dependently reduced by 1.9 g with 1 ms and by 5.7 g with 3 ms. Accordingly, body weight was pulse width-dependently reduced by 2.4 g with 1 ms and by 12.8 g with 3 ms compared to a gain of 5.6 g in sham. (2) GLP-1 level was elevated by both 0.3 and 3 ms at 15 min, but was elevated only with 3 ms at 60 min. (3) GE was delayed to 52.3 % by IES of 3 ms but not 0.3 ms, compared to that at 64.4 % with sham IES. (4) Compared to the geometric center of 7.0 with sham IES, SIT was accelerated by 3 ms to 7.8 but not by 0.3 ms. IES pulse width-dependently reduces food intake and body weight, attributed to the delay of gastric emptying and the acceleration of small bowel transit, as well as the enhancement of GLP-1 secretion.

  4. 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.

  5. 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.

  6. Stimulation of murine peritoneal macrophage functions by neuropeptide Y and peptide YY. Involvement of protein kinase C.

    PubMed Central

    De la Fuente, M; Bernaez, I; Del Rio, M; Hernanz, A

    1993-01-01

    The peptides neuropeptide Y (NPY) and peptide YY (PYY) at concentrations from 10(-12) M to 10(-8) M have been shown in this study to stimulate significantly, in vitro, several functions of resting peritoneal macrophages from BALB/c mice: adherence to substrate, chemotaxis, ingestion of inert particles (latex beads) and foreign cells (Candida albicans), and production of superoxide anion measured by nitroblue tetrazolium reduction. A dose-response relationship was observed, with a maximal stimulation of the macrophage functions studied at 10(-10) M. These effects seem to be produced by specific receptors for the neuropeptides studied in peritoneal macrophages. Whereas the two peptides induced no change of intracellular cyclic AMP, they caused a significant stimulation of protein kinase C (PKC) in murine macrophages. These results suggest that NPY and PYY produce their effects on macrophage function through PKC activation. PMID:8262554

  7. HPLC determination of an oxytocin-like peptide produced by isolated guinea pig Leydig cells: stimulation by ascorbate.

    PubMed

    Kukucka, M A; Misra, H P

    1992-01-01

    Highly purified populations of guinea pig Leydig cells were incubated with a maximally stimulating dose of 100 ng/mL LH for 24 h in the presence of increasing concentrations of sodium ascorbate. Sample supernatants were extracted, concentrated under vacuum, and reconstituted with acidified absolute ethanol. Samples were analyzed for oxytocin using high-performance liquid chromatography with electrochemical detection and known concentrations of an authentic oxytocin standard. Leydig cells stimulated with 0, 25, and 50 microM ascorbate produced and secreted 40.1 +/- 1.23, 77.4 +/- 13.8, 74.2 +/- 26.3 pg of an oxytocin-like peptide, respectively, per 1 x 10(6) cells. These results indicate that guinea pig Leydig cells are capable of producing an oxytocin-like peptide de novo and that low concentrations of ascorbate stimulate the production of this peptide in Leydig cells cultured in vitro.

  8. 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.

  9. Oral insulin stimulates intestinal epithelial cell turnover following massive small bowel resection in a rat and a cell culture model.

    PubMed

    Ben Lulu, Shani; Coran, Arnold G; Shehadeh, Naim; Shamir, Raanan; Mogilner, Jorge G; Sukhotnik, Igor

    2012-02-01

    We have recently reported that oral insulin (OI) stimulates intestinal adaptation after bowel resection and that OI enhances enterocyte turnover in correlation with insulin receptor expression along the villus-crypt axis. The purpose of the present study was to evaluate the effect of OI on intestinal epithelial cell proliferation and apoptosis in a rat model of short bowel syndrome (SBS) and in a cell culture model. Caco-2 cells were incubated with increasing concentrations of insulin. Cell proliferation and apoptosis were determined by FACS cytometry. Cell viability was investigated using the Alamar Blue technique. Male rats were divided into three groups: Sham rats underwent bowel transection, SBS rats underwent a 75% bowel resection, and SBS-OI rats underwent bowel resection and were treated with OI given in drinking water (1 U/ml) from the third postoperative day. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined on day 15. Real time PCR was used to determine the level of bax and bcl-2 mRNA and western blotting was used to determine bax, bcl-2, p-ERK and AKT protein levels. Statistical analysis was performed using the one-way ANOVA test, with P < 0.05 considered statistically significant. Treatment of Caco-2 cells with insulin resulted in a significant increase in cell proliferation (twofold increase after 24 h and 37% increase after 48 h) and cell viability (in a dose-dependent manner), but did not change cell apoptosis. In a rat model of SBS, treatment with OI resulted in a significant increase in all parameters of intestinal adaptation. Elevated cell proliferation rate in insulin treated rats was accompanied by elevated AKT and p-ERK protein levels. Decreased cell apoptosis in SBS-INS rats corresponded with a decreased bax/bcl-2 ratio. Oral insulin stimulates intestinal epithelial cell turnover after massive small bowel resection in a rat model of SBS and a cell culture model.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Opioid peptide receptor stimulation reverses beta-adrenergic effects in rat heart cells.

    PubMed

    Xiao, R P; Pepe, S; Spurgeon, H A; Capogrossi, M C; Lakatta, E G

    1997-02-01

    Opioid peptide receptor (OPR) agonists are co-released with the beta-adrenergic receptor (beta-AR) agonist norepinephrine (NE) from nerve terminals in the heart during sympathetic stimulation. Whereas recent studies indicate that OPR and beta-AR coexist on the surface of cardiac myocytes, whether significant "cross talk" occurs between OPR and beta-AR signaling cascades within heart cells is unknown. In the present study we demonstrate a marked effect of delta-OPR stimulation to modulate beta-adrenergic responses in single isolated rat ventricular myocytes. Nanomolar concentrations (10(-8) M) of the OPR agonist leucine enkephalin (LE), a naturally occurring delta-opioid peptide, inhibited NE-induced increases in sarcolemmal L-type Ca2+ current, cytosolic Ca2+ transient, and contraction. The antiadrenergic effect of LE was pertussis toxin sensitive and abolished by naloxone, an opioid receptor antagonist. In contrast, LE was unable to inhibit the positive inotropic effects induced by equipotent concentrations of 8-(4 chlorophenylthio)-adenosine 3',5'-cyclic monophosphate, a cell-permeant adenosine 3',5'-cyclic monophosphate analog, or by the non-receptor-induced increase in contraction by elevated bathing Ca2+ concentration. These results indicate that an interaction of the OPR and beta-AR systems occurs proximal to activation of the adenosine 3',5'-cyclic monophosphate-dependent protein kinase of the beta-AR intracellular signaling pathway. This modulation of beta-adrenergic effects by OPR activation at the myocyte level may have important implications in the regulation of cardiac Ca2+ metabolism and contractility, particularly during the myocardial response to stress.

  17. 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.

  18. The effect of parachlorophenylalanine and active immunization against vasoactive intestinal peptide on reproductive activities of broiler breeder hens photostimulated with green light.

    PubMed

    Mobarkey, Nader; Avital, Natalie; Heiblum, Rachel; Rozenboim, Israel

    2013-04-01

    Photostimulation of retinal photoreceptors appears to inhibit reproductive activity in birds. In the present study, the involvement of serotonin and vasoactive intestinal peptide was investigated in relation to reproductive failure associated with retinal photostimulation. Hens at 23 wk of age were divided into six rooms equipped with individual cages. At 24 wk of age, three rooms were photostimulated (14L:10D) with white light (control). Three rooms had two parallel lighting systems, red (660 nm) and green (560 nm), which were both on during 6 h of the 14-h light period. Upon photostimulation, the red light was turned off after 6 h, and the green light was left on for a total of 14 h (Green). Five hens from each room served as controls, five hens were immunized against vasoactive intestinal peptide, and five hens received parachlorophenylalanine, an inhibitor of serotonin biosynthesis. Parachlorophenylalanine treatment increased reproductive performance and mRNA expression of GnRH-I, LH-beta and FSH-beta (P < 0.05) in the Green group to levels which did not differ from those of the White (control) group. Immunization against vasoactive intestinal peptide reduced plasma concentration and pituitary mRNA expression of prolactin but did not affect expression of gonadal axis genes. Collectively, the results suggest that retinal photostimulation inhibits the reproductive axis through serotonin and not through vasoactive intestinal peptide.

  19. 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.

  20. Effects of dietary supplementation with antimicrobial peptide-P5 on growth performance, apparent total tract digestibility, faecal and intestinal microflora and intestinal morphology of weanling pigs.

    PubMed

    Yoon, Jung Ho; Ingale, Santosh Laxman; Kim, Jin Soo; Kim, Kwang Hyun; Lohakare, Jayant; Park, Yoon Kyung; Park, Jun Cheol; Kwon, Ill Kyong; Chae, Byung Jo

    2013-02-01

    The increase in drug-resistant bacteria and the ban on antibiotic growth promoters worldwide make the search for novel means of preventing bacterial infection and promoting growth performance imperative. In this sense, antimicrobial peptides are thought to be ideal candidates owing to their antimicrobial properties, broad spectrum of activity and low propensity for development of bacterial resistance. The aim of the present study was to investigate the effect of dietary supplementation with antimicrobial peptide-P5 (AMP-P5) on weanling pig nutrition. A total of 240 weanling pigs were allotted to four treatments on the basis of initial body weight. There were four replicates in each treatment, with 15 pigs per replicate. Dietary treatments were negative control (NC, basal diet without antimicrobial), positive control (PC, basal diet + 1.5 g kg(-1) apramycin), basal diet with 40 mg kg(-1) AMP-P5 (P5-40) and basal diet with 60 mg kg(-1) AMP-P5 (P5-60). Pigs fed the PC or P5-60 diet showed improved (P < 0.05) overall growth performance, apparent total tract digestibility of dry matter, crude protein and gross energy and reduced (P < 0.05) faecal and intestinal coliforms compared with pigs fed the NC diet. The results obtained in this study indicate that dietary supplementation with 60 mg kg(-1) AMP-P5 has the potential to improve the growth performance and apparent total tract digestibility of nutrients and reduce coliforms in weanling pigs. Copyright © 2012 Society of Chemical Industry.

  1. Interactions among secretory immunoglobulin A, CD71, and transglutaminase-2 affect permeability of intestinal epithelial cells to gliadin peptides.

    PubMed

    Lebreton, Corinne; Ménard, Sandrine; Abed, Juliette; Moura, Ivan Cruz; Coppo, Rosanna; Dugave, Christophe; Monteiro, Renato C; Fricot, Aurélie; Traore, Meriem Garfa; Griffin, Martin; Cellier, Christophe; Malamut, Georgia; Cerf-Bensussan, Nadine; Heyman, Martine

    2012-09-01

    The transferrin receptor (CD71) is up-regulated in duodenal biopsy samples from patients with active celiac disease and promotes retrotransport of secretory immunoglobulin A (SIgA)-gliadin complexes. We studied intestinal epithelial cell lines that overexpress CD71 to determine how interactions between SIgA and CD71 promote transepithelial transport of gliadin peptides. We analyzed duodenal biopsy specimens from 8 adults and 1 child with active celiac disease. Caco-2 and HT29-19A epithelial cell lines were transfected with fluorescence-labeled small interfering RNAs against CD71. Interactions among IgA, CD71, and transglutaminase 2 (Tgase2) were analyzed by flow cytometry, immunoprecipitation, and confocal microscopy. Transcytosis of SIgA-CD71 complexes and intestinal permeability to the gliadin 3H-p31-49 peptide were analyzed in polarized monolayers of Caco-2 cells. Using fluorescence resonance energy transfer and in situ proximity ligation assays, we observed physical interactions between SIgA and CD71 or CD71 and Tgase2 at the apical surface of enterocytes in biopsy samples and monolayers of Caco-2 cells. CD71 and Tgase2 were co-precipitated with SIgA, bound to the surface of Caco-2 cells. SIgA-CD71 complexes were internalized and localized in early endosomes and recycling compartments but not in lysosomes. In the presence of celiac IgA or SIgA against p31-49, transport of intact 3H-p31-49 increased significantly across Caco-2 monolayers; this transport was inhibited by soluble CD71 or Tgase2 inhibitors. Upon binding to apical CD71, SIgA (with or without gliadin peptides) enters a recycling pathway and avoids lysosomal degradation; this process allows apical-basal transcytosis of bound peptides. This mechanism is facilitated by Tgase2 and might be involved in the pathogenesis of celiac disease. Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.

  2. 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

  3. An antimicrobial peptide-A3: effects on growth performance, nutrient retention, intestinal and faecal microflora and intestinal morphology of broilers.

    PubMed

    Choi, S C; Ingale, S L; Kim, J S; Park, Y K; Kwon, I K; Chae, B J

    2013-01-01

    1. The present study investigated the effects of dietary supplementation with an antimicrobial peptide-A3 (AMP-A3) on growth performance, nutrient retention, intestinal microflora and intestinal morphology of broilers. 2. A total of 320-d-old chicks (Ross 308, average BW 44.0 ± 3.4 g) were randomly allotted to 4 dietary treatments on the basis of initial body weight (BW). The dietary treatments were negative control (NC; basal diet), positive control (PC; basal diet + 15 mg avilamycin/kg diet) and AMP-A3 (basal diet supplemented with 60 or 90 mg/kg AMP-A3). The NC diet was considered as 0 mg/kg AMP-A3 treatment. Experimental diets were given in two phases: starter phase (d 0-21) and finisher phase (d 22-35). 3. The overall BW gain and retention of dry matter (DM), gross energy (GE; d 19-21) and crude protein (CP; d 19-21 and d 33-35) were greater in birds fed on the PC and 90 mg/kg AMP-A3 diets than in birds fed on the NC diet. Also, an increase in dietary AMP-A3 linearly improved BW gain and retention of DM, GE (d 19-21) and CP (d 19-21 and d 33-35). 4. Birds fed on the PC and 90 mg/kg AMP-A3 diets had fewer excreta coliforms (d 21 and d 35), total anaerobic bacteria (TAB) and Clostridium spp. (d 35) and ileum and caecum coliforms (d 35) than birds fed on the NC diet. In addition, birds fed on the diet supplemented with increasing levels of AMP-A3 had linearly reduced excreta TAB (d 35), Clostridium spp. and coliforms (d 21 and d 35) and ileum and caecum coliforms (d 35). 5. Birds fed on the PC and 90 mg/kg AMP-A3 diets had greater villus height of the duodenum, jejunum and ileum than birds fed on the NC diet. Moreover, birds fed on increasing levels of AMP-A3 diet had increased (linear) villus height of the duodenum, jejunum and ileum. 6. These results indicate that 90 mg/kg AMP-A3 has the potential to improve growth performance, nutrient retention and intestinal morphology and to reduce harmful microorganisms in broilers and can be used as a potential

  4. Saccharomyces boulardii Stimulates Intestinal Immunoglobulin A Immune Response to Clostridium difficile Toxin A in Mice

    PubMed Central

    Qamar, Amir; Aboudola, Samer; Warny, Michel; Michetti, Pierre; Pothoulakis, Charalabos; LaMont, J. Thomas; Kelly, Ciarán P.

    2001-01-01

    Saccharomyces boulardii is a nonpathogenic yeast that protects against antibiotic-associated diarrhea and recurrent Clostridium difficile colitis. The administration of C. difficile toxoid A by gavage to S. boulardii-fed BALB/c mice caused a 1.8-fold increase in total small intestinal immunoglobulin A levels (P = 0.003) and a 4.4-fold increase in specific intestinal anti-toxin A levels (P < 0.001). Enhancing host intestinal immune responses may be an important mechanism for S. boulardii-mediated protection against diarrheal illnesses. PMID:11254650

  5. Distribution of substance P and vasoactive intestinal peptide in the human liver: light and electron immunoperoxidase methods of observation.

    PubMed

    Ueno, T; Inuzuka, S; Torimura, T; Sakata, R; Sakamoto, M; Gondo, K; Aoki, T; Tanikawa, K; Tsutsumi, V

    1991-11-01

    The localization of substance P (SP) and vasoactive intestinal peptide (VIP) in 12 normal human liver tissues was examined by light and electron immunohistochemistry using immunoperoxidase methods. SP and VIP immunoreactive nerve fibers were observed around portal veins, bile ducts, and hepatic arteries in portal areas, along sinusoids and hepatocytes in hepatic lobules, and around central veins. More SP and VIP immunoreactive nerve fibers were present in the portal areas than in other regions. Moreover, SP and VIP containing nerve endings were localized close to myofibroblasts, Ito cells, fibroblasts and endothelial cells of blood vessels, and sinusoids. The results suggested that part of the innervation of the human liver may be related to the contraction and relaxation of the cells close to nerve endings, and to the regulation of hemodynamic processes by the neurotransmitters such as SP and VIP at the hepatic lobular level.

  6. Impact of lipases on the protective effect of SEDDS for incorporated peptide drugs towards intestinal peptidases.

    PubMed

    Leonaviciute, Gintare; Zupančič, Ožbej; Prüfert, Felix; Rohrer, Julia; Bernkop-Schnürch, Andreas

    2016-07-11

    The aim of this study is the development of self-emulsifying drug delivery systems (SEDDS) differing in amounts of ester substructures and to evaluate their stability in presence of pancreatic lipase and protective effect against luminal enzymatic metabolism using leuprorelin as model peptide drug. Hydrophobic leuprolide oleate was incorporated into three different SEDDS formulations and their stability towards pancreatic lipases was investigated utilizing a dynamic in vitro digestion model. Protective effect of SEDDS in respect to peptide drug stability against proteolytic enzymes, trypsin and α-chymotrypsin, was determined via HPLC. Results of in vitro digestion demonstrated that 80% of SEDDS containing the highest amount of ester linkages was degraded within 60min. In comparison to that, SEDDS without ester bonds showed no degradation. With increasing oil droplets hydrolysis the remaining amount of peptide encapsulated into formulation decreased. Furthermore, after 180min incubation with trypsin up to 33.5% and with α-chymotrypsin up to 60.5% of leuprolide oleate was intact while leuprorelin acetate aqueous solution was completely metabolized by trypsin within 120min and by α-chymotrypsin within 5min. Protective effect in environment containing lipases was lower due to oil phase degradation, however, the amount of peptide in ester-free SEDDS was remarkably higher compared to SEDDS susceptible to lipases. The present study revealed that SEDDS stable towards hydrolysis is able to exhibit a protective effect for oral peptide delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Intestinal growth in parenterally-fed rats induced by the combined effects of glucagon-like peptide 2 and epidermal growth factor.

    PubMed

    Kitchen, Paul A; Goodlad, Robert A; FitzGerald, Anthony J; Mandir, Nikki; Ghatei, Mohammed A; Bloom, Stephen R; Berlanga-Acosta, Jorge; Playford, Raymond J; Forbes, Alastair; Walters, Julian R F

    2005-01-01

    Parenteral nutrition and the absence of luminal feeding result in impaired intestinal growth and differentiation of enterocytes. Glucagon-like peptide 2 (GLP-2) and epidermal growth factor (EGF) have each been shown to have trophic effects on the intestine, and thus have the potential to benefit patients fed parenterally, such as those with intestinal failure from short bowel syndrome. We report studies aimed to determine whether there may be synergistic effects of these 2 peptides. Rats were established on parenteral nutrition (PN) and infused for 6 days with GLP-2 (20 microg/d), EGF (20 microg/d), or GLP-2 + EGF (20 microg/d of each). These groups were compared with untreated PN-fed and orally-fed controls. Tissue was obtained from small intestine and colon to determine growth, proliferation, and representative gene expression. Small intestinal weight was increased by 75%, 43%, and 116% in the GLP-2, EGF, and GLP-2 + EGF groups, respectively, compared with PN controls (all p < .001). Cell proliferation increased with GLP-2, EGF, and GLP-2 + EGF in proximal small intestine by factors of 2.3, 1.7, and 3.4 respectively (p < .001). A synergistic effect on villous and crypt area was observed in the proximal small intestine when GLP-2 and EGF were combined (p < .05). GLP-2 had no effect in the colon, unlike EGF. Further studies showed GLP-2 + EGF significantly increased expression in distal small intestine of transcripts for the bile acid transport protein IBABP (p < .05) and showed a significant correlation between the expression of IBABP and the transcription factor HNF-4. Both GLP-2 and EGF upregulate growth of the small intestine, and this is augmented when GLP-2 and EGF are combined. These findings may lead to improved treatment of patients receiving PN.

  8. 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.

  9. 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.

  10. Nitric oxide and vasoactive intestinal peptide as co-transmitters of airway smooth-muscle relaxation: analysis in neuronal nitric oxide synthase knockout mice.

    PubMed

    Hasaneen, Nadia A; Foda, Hussein D; Said, Sami I

    2003-09-01

    Both vasoactive intestinal peptide (VIP) and nitric oxide (NO) relax airway smooth muscle and are potential co-transmitters of neurogenic airway relaxation. The availability of neuronal NO synthase (nNOS) knockout mice (nNOS-/-) provides a unique opportunity for evaluating NO. To evaluate the relative importance of NO, especially that generated by nNOS, and VIP as transmitters of the inhibitory nonadrenergic, noncholinergic (NANC) system. In this study, we compared the neurogenic (tetrodotoxin-sensitive) NANC relaxation of tracheal segments from nNOS-/- mice and control wild-type mice (nNOS(+/+)), induced by electrical field stimulation (EFS). We also examined the tracheal contractile response to methacholine and its relaxant response to VIP. EFS (at 60 V for 2 ms, at 10, 15, or 20 Hz) dose-dependently reduced tracheal tension, and the relaxations were consistently smaller (approximately 40%) in trachea from nNOS-/- mice than from control wild-type mice (p < 0.001). VIP (10(- 8) to 10(-6) mol/L) induced concentration-dependent relaxations that were approximately 50% smaller in nNOS-/- tracheas than in control tracheas. Methacholine induced concentration-dependent contractions that were consistently higher in the nNOS-/- tracheas relative to wild-type mice tracheas (p > 0.05). Our data suggest that, in mouse trachea, NO is probably responsible for mediating a large (approximately 60%) component of neurogenic NANC relaxation, and a similar (approximately 50%) component of the relaxant effect of VIP. The results imply that NO contributes significantly to neurogenic relaxation of mouse airway smooth muscle, whether due to neurogenic stimulation or to the neuropeptide VIP.

  11. GPR119 is essential for oleoylethanolamide-induced glucagon-like peptide-1 secretion from the intestinal enteroendocrine L-cell.

    PubMed

    Lauffer, Lina M; Iakoubov, Roman; Brubaker, Patricia L

    2009-05-01

    Intestinal L-cells secrete the incretin glucagon-like peptide-1 (GLP-1) in response to ingestion of nutrients, especially long-chain fatty acids. The Galphas-coupled receptor GPR119 binds the long-chain fatty acid derivate oleoylethanolamide (OEA), and GPR119 agonists enhance GLP-1 secretion. We therefore hypothesized that OEA stimulates GLP-1 release through a GPR119-dependent mechanism. Murine (m) GLUTag, human (h) NCI-H716, and primary fetal rat intestinal L-cell models were used for RT-PCR and for cAMP and GLP-1 radioimmunoassay. Anesthetized rats received intravenous or intraileal OEA, and plasma bioactive GLP-1, insulin, and glucose levels were determined by enzyme-linked immunosorbent assay or glucose analyzer. GPR119 messenger RNA was detected in all L-cell models. OEA treatment (10 micromol/l) of mGLUTag cells increased cAMP levels (P < 0.05) and GLP-1 secretion (P < 0.001) in all models, with desensitization of the secretory response at higher concentrations. GLP-1 secretion was further enhanced by prevention of OEA degradation using the fatty acid amide hydrolase inhibitor, URB597 (P < 0.05-0.001 vs. OEA alone), and was abolished by H89-induced inhibition of protein kinase A. OEA-induced cAMP levels and GLP-1 secretion were significantly reduced in mGLUTag cells transfected with GPR119-specific small interfering RNA (P < 0.05). Application of OEA (10 micromol/l) directly into the rat ileum, but not intravenously, increased plasma bioactive GLP-1 levels in euglycemic animals by 1.5-fold (P < 0.05) and insulin levels by 3.9-fold (P < 0.01) but only in the presence of hyperglycemia. The results of these studies demonstrate, for the first time, that OEA increases GLP-1 secretion from intestinal L-cells through activation of the novel GPR119 fatty acid derivate receptor in vitro and in vivo.

  12. Breakdown of gliadin peptides by intestinal brush borders from coeliac patients.

    PubMed Central

    Bruce, G; Woodley, J F; Swan, C H

    1984-01-01

    The 'missing peptidase' hypothesis to explain the aetiology of coeliac disease has never been satisfactorily resolved and recent reports suggest that coeliac brush borders may have depressed levels of specific peptidase enzymes. It has been inferred from these studies that the subsequent brush border digestion of gliadin peptides may therefore be defective. In this present study a sensitive fluorometric assay was used to measure the hydrolysis of a peptic-tryptic digest of gliadin by both normal and coeliac brush borders. The coeliac brush borders were as efficient as the normals in hydrolysing gliadin peptides and showed no depression of any specific peptidase activity. PMID:6381246

  13. 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

  14. Intestinal Sodium Glucose Cotransporter 1 Inhibition Enhances Glucagon-Like Peptide-1 Secretion in Normal and Diabetic Rodents.

    PubMed

    Oguma, Takahiro; Nakayama, Keiko; Kuriyama, Chiaki; Matsushita, Yasuaki; Yoshida, Kumiko; Hikida, Kumiko; Obokata, Naoyuki; Tsuda-Tsukimoto, Minoru; Saito, Akira; Arakawa, Kenji; Ueta, Kiichiro; Shiotani, Masaharu

    2015-09-01

    The sodium glucose cotransporter (SGLT) 1 plays a major role in glucose absorption and incretin hormone release in the gastrointestinal tract; however, the impact of SGLT1 inhibition on plasma glucagon-like peptide-1 (GLP-1) levels in vivo is controversial. We analyzed the effects of SGLT1 inhibitors on GLP-1 secretion in normoglycemic and hyperglycemic rodents using phloridzin, CGMI [3-(4-cyclopropylphenylmethyl)-1-(β-d-glucopyranosyl)-4-methylindole], and canagliflozin. These compounds are SGLT2 inhibitors with moderate SGLT1 inhibitory activity, and their IC50 values against rat SGLT1 and mouse SGLT1 were 609 and 760 nM for phloridzin, 39.4 and 41.5 nM for CGMI, and 555 and 613 nM for canagliflozin, respectively. Oral administration of these inhibitors markedly enhanced and prolonged the glucose-induced plasma active GLP-1 (aGLP-1) increase in combination treatment with sitagliptin, a dipeptidyl peptidase-4 (DPP4) inhibitor, in normoglycemic mice and rats. CGMI, the most potent SGLT1 inhibitor among them, enhanced glucose-induced, but not fat-induced, plasma aGLP-1 increase at a lower dose compared with canagliflozin. Both CGMI and canagliflozin delayed intestinal glucose absorption after oral administration in normoglycemic rats. The combined treatment of canagliflozin and a DPP4 inhibitor increased plasma aGLP-1 levels and improved glucose tolerance compared with single treatment in both 8- and 13-week-old Zucker diabetic fatty rats. These results suggest that transient inhibition of intestinal SGLT1 promotes GLP-1 secretion by delaying glucose absorption and that concomitant inhibition of intestinal SGLT1 and DPP4 is a novel therapeutic option for glycemic control in type 2 diabetes mellitus. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  15. Calcitriol stimulates gene expression of cathelicidin antimicrobial peptide in breast cancer cells with different phenotype.

    PubMed

    García-Quiroz, Janice; García-Becerra, Rocío; Santos-Martínez, Nancy; Avila, Euclides; Larrea, Fernando; Díaz, Lorenza

    2016-11-10

    In normal and neoplastic cells, growth-promoting, proangiogenic, cytotoxic and pro-apoptotic effects have all been attributed to cathelicidin antimicrobial peptide (CAMP). Nevertheless, little is known about the factors regulating this peptide expression in breast cancer. Herein we asked if the well-known antineoplastic hormone calcitriol could differentially modulate CAMP gene expression in human breast cancer cells depending on the cell phenotype in terms of efficacy and potency. The established breast cancer cell lines MCF7, BT-474, HCC1806, HCC1937, SUM-229PE and a primary cell culture generated from invasive ductal breast carcinoma were used in this study. Calcitriol regulation of cathelicidin gene expression in vitro and in human breast cancer xenografts was studied by real time PCR. Tumorigenicity was evaluated for each cell line in athymic mice. Estrogen receptor (ER)α + breast cancer cells showed the highest basal CAMP gene expression. When incubated with calcitriol, CAMP gene expression was stimulated in a dose-dependent and cell phenotype-independent manner. Efficacy of calcitriol was lower in ERα + cells when compared to ERα- cells (<10 vs. >70 folds over control, respectively). Conversely, calcitriol lowest potency upon CAMP gene expression was observed in the ERα-/EGFR+ SUM-229PE cell line (EC50 = 70.8 nM), while the highest was in the basal-type/triple-negative cells HCC1806 (EC50 = 2.13 nM) followed by ERα + cells MCF7 and BT-474 (EC50 = 4.42 nM and 14.6 nM, respectively). In vivo, lower basal CAMP gene expression was related to increased tumorigenicity and lack of ERα expression. Xenografted triple-negative breast tumors of calcitriol-treated mice showed increased CAMP gene expression compared to vehicle-treated animals. Independently of the cell phenotype, calcitriol provoked a concentration-dependent stimulation on CAMP gene expression, showing greater potency in the triple negative HCC1806 cell line. Efficacy of

  16. The functional involvement of gut-expressed sweet taste receptors in glucose-stimulated secretion of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY).

    PubMed

    Steinert, R E; Gerspach, A C; Gutmann, H; Asarian, L; Drewe, J; Beglinger, C

    2011-08-01

    Enteroendocrine cells are thought to directly sense nutrients via α-gustducin coupled taste receptors (originally identified in the oral epithelium) to modulate the secretion of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY). We measured mRNA expression of α-gustducin and T1R3 along the human gut; immunohistochemistry was used to confirm co-localization with GLP-1. Functional implication of sweet taste receptors in glucose-stimulated secretion of GLP-1 and PYY was determined by intragastric infusion of glucose with or without lactisole (a sweet taste receptor antagonist) in 16 healthy subjects. α-gustducin was expressed in a region-specific manner (predominantly in the proximal gut and less in ileum and colon, P < 0.05). Both, T1R3 and α-gustducin were co-localized with GLP-1. Glucose-stimulated secretions of GLP-1 (P = 0.026) and PYY (P = 0.034) were reduced by blocking sweet receptors with lactisole. Key proteins implicated in taste signaling are present in the human gut and co-localized with GLP-1 suggesting that these proteins are functionally linked to peptide secretion from enteroendocrine cells. Glucose-stimulated secretion of GLP-1 and PYY is reduced by a sweet taste antagonist, suggesting the functional involvement of gut-expressed sweet taste receptors in glucose-stimulated secretion of both peptides in humans. Copyright © 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  17. 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

  18. 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.

  19. Both Intestinal and Hepatic Lipoprotein Production Are Stimulated by an Acute Elevation of Plasma Free Fatty Acids in Humans

    PubMed Central

    Duez, Hélène; Lamarche, Benoît; Valéro, René; Pavlic, Mirjana; Proctor, Spencer; Xiao, Changting; Szeto, Linda; Patterson, Bruce W.; Lewis, Gary F.

    2013-01-01

    Background Hepatic lipoprotein production has been shown previously to be regulated by free fatty acid (FFA) flux to the liver, whereas intestinal lipoprotein production is stimulated mainly by ingested fat absorbed from the intestinal lumen. Emerging evidence indicates that intestinal lipoprotein production is increased in insulin resistance and type 2 diabetes mellitus, conditions that are associated with increased levels of circulating FFAs. Here we investigated whether short-term elevation of plasma FFAs stimulates intestinal apolipoprotein (apo) B-48– and hepatic apoB-100–containing triglyceride-rich lipoprotein (TRL) production in humans in the fed state. Methods and Results TRL apoB-48 and apoB-100 metabolism were examined in 12 healthy men during a constant fed state. The studies were as follows, respectively: (1) Intralipid/heparin was infused intravenously immediately before and during the kinetics study to induce an ≈3-fold difference in plasma FFA compared with the saline study; (2) saline was infused intravenously as a control. ApoB-48– and apoB-100–containing TRL production and clearance were determined with a 12-hour primed constant infusion of [D3]L-leucine and multicompartmental kinetic modeling. TRL apoB-48 production rate was 69% higher in the Intralipid/heparin study than in the saline control (5.95±1.13 versus 3.53±0.58 mg/kg per day; P=0.027), and there was no significant difference in TRL apoB-48 clearance. TRL apoB-100 concentrations were also increased (P<0.001) and TRL apoB-100 production rate was 35% higher in the Intralipid/ heparin study compared with saline (28±4 versus 21±3 mg/kg per day; P=0.020). Conclusions This is the first study to demonstrate that intestinal TRL apoB-48 production is increased after short-term elevation of plasma FFAs in humans in the fed state, similar to the well-described stimulation of hepatic TRL apoB100–containing particles by FFAs. PMID:18443237

  20. 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

  1. 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

  2. Treatment of adjuvant arthritis with granulocyte-colony stimulating factor and peptide derived from heat shock protein 65.

    PubMed

    Brendolan, Andrea; Higuchi, Masanori; Sibley, Richard; Strober, Samuel

    2003-01-01

    Adjuvant arthritis in Lewis rats is induced by the subcutaneous injection of Mycobacterium tuberculosis in mineral oil, and the predominant T cell immune reactivity is against the heat shock protein 65 derived peptide 176-190. We treated Lewis rats with human recombinant G-CSF followed by (i.v) administration of peptide 176-190 after induction of adjuvant arthritis (AA), and observed decreased disease severity, joint destruction, new bone formation and joint ankylosis. Treatment with G-CSF alone was also effective, but to a lesser extent. In addition, we found that splenocytes from rats treated with G-CSF had reduced antigen presenting capacity compared with splenocytes from vehicle treated rats. Primed lymph node cells from G-CSF plus peptide treated rats showed a marked reduction in proliferation and secretion of IFN-gamma after stimulation with the heat shock protein peptide in vitro as compared to controls.

  3. 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.

  4. 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.

  5. 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.

  6. CaSR stimulates secretion of Wnt5a from colonic myofibroblasts to stimulate CDX2 and sucrase-isomaltase using Ror2 on intestinal epithelia.

    PubMed

    Pacheco, Ivan I; Macleod, R John

    2008-10-01

    To understand whether extracellular calcium-sensing receptor (CaSR) expression on colonic myofibroblast cells (18Co) contributed to epithelial homeostasis, we activated the CaSR with 5 mM Ca(2+), screened by RT-PCR Wnt family members, and measured their secretion. Transcripts for Wnt 1, 2, 2b, 3a, 4, and 7a were either absent or unchanged whereas Wnt3 decreased and Wnt5a increased. We assessed Wnt5a secretion by Western blot. High Ca(2+) (5 mM) substantially increased Wnt5a secretion; small interfering RNA (siRNA) against the CaSR reduced this to constitutive amounts. Expression of Wnt5a plasmid but not Wnt1 or Wnt3a increased caudal homeodomain factor CDX2 transcripts and protein in HT-29 adenocarcinoma cells. Wnt5a increased activity of a sucrase-isomaltase (SI) promoter in Caco-2BBE cells. Wnt5a protein stimulation of CDX2 transcripts and protein and SI reporter were increased by overexpression of wild-type Ror2, a Wnt5a receptor, and reduced with siRNA against Ror2. CaSR activation of HT-29 cells increased Ror2 protein expression. Ror2 protein was expressed in mouse jejunum from crypt base to villus tip and in the colon on surface epithelia. Our results show that activation of a G protein-coupled receptor, the CaSR, stimulates secretion of Wnt5a from myofibroblasts. Stimulation of epithelia by the CaSR increased the expression of a receptor for Wnt5a, the tyrosine kinase Ror2, suggesting existence of a unique paracrine relationship for CDX2 homoeostasis in the intestine and revealing new contributions of CaSR-activated myofibroblasts to intestinal stem cell niche microenvironments.

  7. 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

  8. 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.

  9. Phospholipase D catalyzes phospholipid metabolism in chemotactic peptide-stimulated HL-60 granulocytes

    SciTech Connect

    Pai, J.K.; Siegel, M.I.; Egan, R.W.; Billah, M.M.

    1988-09-05

    There exists circumstantial evidence for activation of phospholipase D (PLD) in intact cells. However, because of the complexity of phospholipid remodeling processes, it is essential to distinguish PLD clearly from other phospholipases and phospholipid remodeling enzymes. Therefore, to establish unequivocally PLD activity in dimethyl sulfoxide-differentiated HL-60 granulocytes, to demonstrate the relative contribution of PLD to phospholipid turnover, and to validate the hypothesis that the formation of phosphatidylethanol is an expression of PLD-catalyzed transphosphatidylation, we have developed methodologies to label HL-60 granulocytes in 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine (alkyl-PC) with 32P without labeling cellular ATP. These methodologies involve (a) synthesis of alkyl-lysoPC containing 32P by a combination of enzymatic and chemical procedures and (b) incubation of HL-60 granulocytes with this alkyl-(32P) lysoPC which enters the cell and becomes acylated into membrane-associated alkyl-(32P)PC. Upon stimulation of these 32P-labeled cells with the chemotactic peptide, N-formyl-Met-Leu-Phe (fMLP), alkyl-(32P)phosphatidic acid (alkyl-(32P)PA) is formed rapidly. Because, under these conditions, cellular ATP has not been labeled with 32P, alkyl-(32P)PA must be formed via PLD-catalyzed hydrolysis of alkyl-(32P)PC at the terminal phosphodiester bond. This result conclusively demonstrates fMLP-induced activation of PLD in HL-60 granulocytes. These 32P-labeled HL-60 granulocytes have also been stimulated in the presence of ethanol to produce alkyl-(32P)phosphatidylethanol (alkyl-(32P)PEt). Formation of alkyl-(32P)PEt parallels that of alkyl-(32P)PA with respect to time course, fMLP concentration, inhibition by a specific fMLP antagonist (t-butoxycarbonyl-Met-Leu-Phe), and Ca2+ concentration.

  10. Curcumin and chronic kidney disease (CKD): major mode of action through stimulating endogenous intestinal alkaline phosphatase.

    PubMed

    Ghosh, Siddhartha S; Gehr, Todd W B; Ghosh, Shobha

    2014-12-02

    Curcumin, an active ingredient in the traditional herbal remedy and dietary spice turmeric (Curcuma longa), has significant anti-inflammatory properties. Chronic kidney disease (CKD), an inflammatory disease, can lead to end stage renal disease resulting in dialysis and transplant. Furthermore, it is frequently associated with other inflammatory disease such as diabetes and cardiovascular disorders. This review will focus on the clinically relevant inflammatory molecules that play a role in CKD and associated diseases. Various enzymes, transcription factors, growth factors modulate production and action of inflammatory molecules; curcumin can blunt the generation and action of these inflammatory molecules and ameliorate CKD as well as associated inflammatory disorders. Recent studies have shown that increased intestinal permeability results in the leakage of pro-inflammatory molecules (cytokines and lipopolysaccharides) from gut into the circulation in diseases such as CKD, diabetes and atherosclerosis. This change in intestinal permeability is due to decreased expression of tight junction proteins and intestinal alkaline phosphatase (IAP). Curcumin increases the expression of IAP and tight junction proteins and corrects gut permeability. This action reduces the levels of circulatory inflammatory biomolecules. This effect of curcumin on intestine can explain why, despite poor bioavailability, curcumin has potential anti-inflammatory effects in vivo and beneficial effects on CKD.

  11. Changes in the inhibitory responses to electrical field stimulation of intestinal smooth muscle from Trichinella spiralis infected rats.

    PubMed

    Tanovic, Adnan; Jiménez, Marcel; Fernández, Ester

    2002-11-15

    Functional motor changes and morphological alterations have been associated with intestinal inflammation. The aim of this work was to study functional motor changes in inflamed and non-inflamed intestinal segments of Trichinella spiralis infected rats. Thickness of muscle layers and cell infiltration during infection were also evaluated. Segments of rat jejunum and ileum were placed in organ bath and relaxations of the longitudinal muscle in response to electrical field stimulation (EFS) were recorded. During the post-infection (PI) period EFS-induced relaxations in ileum were decreased. Maximal decreases in relaxation were found on day 14-23 PI for ileum, whereas non significant changes were observed in jejunal samples throughout the experimental period. The sensitivity of the EFS-induced relaxations to the NO synthase inhibitor Nomega-nitro-L-arginine (L-NNA) and to the soluble guanylate cyclase inhibitor oxadiazolo-quinoxalin-1-one (ODQ) was decreased on day 14 PI for jejunum, whereas in the ileum it lasted from day 14-23 PI. The sensitivity of EFS-induced relaxations to apamin (a small conductance calcium activated potassium channel blocker) disappeared between day 6-23 PI for both jejunum and ileum. In contrast, the sensitivity of the EFS-induced relaxations to the K(+) channel blockers tetraethylamonium (TEA) and tetrapenthylammonium (TPEA) chloride was similar for healthy tissue and for tissue obtained form infected animals. Distribution and density of NADPH-diaphorase positive neurons was similar in tissue obtained form healthy and infected animals. In conclusion, intestinal inflammation induces functional and structural changes in both worm-free and worm-positive intestinal segments. Increased muscle thickness was similar for both inflamed and noninflamed segments but the most prominent functional changes i.e. a long-lasting decrease of EFS-induced relaxation was found in non-inflamed ileal segments.

  12. 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.

  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. 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.

  15. 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.

  16. 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.

  17. Genetic susceptibility to refractive error: association of vasoactive intestinal peptide receptor 2 (VIPR2) with high myopia in Chinese.

    PubMed

    Yiu, Wai Chi; Yap, Maurice K H; Fung, Wai Yan; Ng, Po Wah; Yip, Shea Ping

    2013-01-01

    Myopia is the most common ocular disease worldwide. We investigated the association of high myopia with the common single nucleotide polymorphisms (SNPs) of five candidate genes - early growth response 1 (EGR1), v-fos FBJ murine osteosarcoma viral oncogene homolog (FOS), jun oncogene (JUN), vasoactive intestinal peptide (VIP), and vasoactive intestinal peptide receptor 2 (VIPR2). We recruited 1200 unrelated Chinese subjects with 600 cases (spherical equivalent ≤-8.00 diopters) and 600 controls (spherical equivalent within ±1.00 diopter). A discovery sample set was formed from 300 cases and 300 controls, and a replication sample set from the remaining samples. Tag SNPs were genotyped for the discovery sample set, and the most significant haplotypes and their constituent SNPs were followed up with the replication sample set. The allele and haplotype frequencies in cases and controls were compared by logistic regression adjusted for sex and age to give P a values, and multiple comparisons were corrected by permutation test to give P aemp values. Odd ratios (OR) were calculated accordingly. In the discovery phase, EGR1, JUN and VIP did not show any significant association while FOS and VIPR2 demonstrated significant haplotype association with high myopia. In the replication phase, the haplotype association for VIPR2 was successfully replicated, but not FOS. In analysis combining both sample sets, the most significant association signals of VIPR2 were the single marker rs2071625 (P a = 0.0008, P aemp = 0.0046 and OR = 0.75) and the 4-SNP haplotype window rs2071623-rs2071625-rs2730220-rs885863 (omnibus test, P a = 9.10e-10 and P aemp = 0.0001) with one protective haplotype (GGGG: P aemp = 0.0002 and OR = 0.52) and one high-risk haplotype (GAGA: P aemp = 0.0027 and OR = 4.68). This 4-SNP haplotype window was the most significant in all sample sets examined. This is the first study to suggest a role of VIPR2 in the genetic

  18. Genetic Susceptibility to Refractive Error: Association of Vasoactive Intestinal Peptide Receptor 2 (VIPR2) with High Myopia in Chinese

    PubMed Central

    Yiu, Wai Chi; Yap, Maurice K. H.; Fung, Wai Yan; Ng, Po Wah; Yip, Shea Ping

    2013-01-01

    Myopia is the most common ocular disease worldwide. We investigated the association of high myopia with the common single nucleotide polymorphisms (SNPs) of five candidate genes – early growth response 1 (EGR1), v-fos FBJ murine osteosarcoma viral oncogene homolog (FOS), jun oncogene (JUN), vasoactive intestinal peptide (VIP), and vasoactive intestinal peptide receptor 2 (VIPR2). We recruited 1200 unrelated Chinese subjects with 600 cases (spherical equivalent ≤−8.00 diopters) and 600 controls (spherical equivalent within ±1.00 diopter). A discovery sample set was formed from 300 cases and 300 controls, and a replication sample set from the remaining samples. Tag SNPs were genotyped for the discovery sample set, and the most significant haplotypes and their constituent SNPs were followed up with the replication sample set. The allele and haplotype frequencies in cases and controls were compared by logistic regression adjusted for sex and age to give Pa values, and multiple comparisons were corrected by permutation test to give Paemp values. Odd ratios (OR) were calculated accordingly. In the discovery phase, EGR1, JUN and VIP did not show any significant association while FOS and VIPR2 demonstrated significant haplotype association with high myopia. In the replication phase, the haplotype association for VIPR2 was successfully replicated, but not FOS. In analysis combining both sample sets, the most significant association signals of VIPR2 were the single marker rs2071625 (Pa = 0.0008, Paemp = 0.0046 and OR = 0.75) and the 4-SNP haplotype window rs2071623-rs2071625-rs2730220-rs885863 (omnibus test, Pa = 9.10e-10 and Paemp = 0.0001) with one protective haplotype (GGGG: Paemp = 0.0002 and OR = 0.52) and one high-risk haplotype (GAGA: Paemp = 0.0027 and OR = 4.68). This 4-SNP haplotype window was the most significant in all sample sets examined. This is the first study to suggest a role of VIPR2 in the genetic susceptibility

  19. 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

  20. 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.

  1. 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)

  2. 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.

  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. Endocrine cells producing peptide hormones in the intestine of Nile tilapia: distribution and effects of feeding and fasting on the cell density.

    PubMed

    Pereira, Raquel Tatiane; de Freitas, Thaiza Rodrigues; de Oliveira, Izabela Regina Cardoso; Costa, Leandro Santos; Vigliano, Fabricio Andrés; Rosa, Priscila Vieira

    2017-05-13

    Endocrine cells (ECs) act as a luminal surveillance system responding to either the presence or absence of food in the gut through the secretion of peptide hormones. The aim of this study was to analyze the effects of feeding and fasting on the EC peptide-specific distribution along the intestine of Nile tilapia. We assessed the density of ECs producing gastrin (GAS), cholecystokinin-8 (CCK-8), neuropeptide Y (NPY), and calcitonin gene-related peptide (CGRP) in nine segments of the intestine using immunohistochemistry. Our results show that ECs immunoreactive to CCK-8, GAS, NPY, and CGRP can be found along all the intestinal segments sampled, from the midgut to hindgut, although differences in their distribution along the gut were observed. Regarding nutrient status, we found that the anterior segments of the midgut seem to be the main site responding to luminal changes in Nile tilapia. The NPY+ and CGRP+ EC densities increased in the fasted group, while the amount of CCK-8+ ECs were higher in the fed group. No effects of fasting or feeding were found in the GAS+ EC densities. Changes in ECs density were found only at the anterior segments of the intestine which may be due to the correlation between vagus nerve anatomy, EC location, and peptide turnover. Lastly, ECs may need to be considered an active cell subpopulation that may adapt and respond to different nutrient status as stimuli. Due to the complexity of the enteroendocrine system and its importance in fish nutrition, much remains to be elucidated and it deserves closer attention.

  6. Nucleotide sequence and expression of relaxin-like gonad-stimulating peptide gene in starfish Asterina pectinifera.

    PubMed

    Haraguchi, Shogo; Ikeda, Narumi; Abe, Michiko; Tsutsui, Kazuyoshi; Mita, Masatoshi

    2016-02-01

    Starfish gonad-stimulating substance (GSS) is the only known invertebrate peptide hormone responsible for final gamete maturation, rendering it functionally analogous to gonadotropins in vertebrates. Because GSS belongs to the relaxin-like peptide family, we propose renaming for starfish gonadotropic hormone as relaxin-like gonad-stimulating peptide (RGP). This study examined the primary structure and expression regulation of the RGP gene in starfish Asterina pectinifera. RGP consisted of 3896 base pairs (bp) divided over two exons, exon 1 of 208 bp and exon 2 of 2277 bp, and one intron of 1411 bp. Promoter sequences, CAAT and TATA boxes, were present in the 5'-upstream region of the coding DNA sequence of RGP. The transcript was 2485 bases (b) in length. The AAUAAA polyadenylation signal was found in 3'-untranslated region over 2kb away from the stop codon. This showed that only 14% of the RGP mRNA was translated into the peptide, because a size of the open-reading frame was 351 b. Furthermore, an analysis by using real-time quantitative PCR with specific primers for RGP showed that mRNA of RGP was expressed at high levels in the radial nerves. Expression was also observed in the cardiac stomachs, although the level was low, and trace levels were detected in the gonads, pyloric caeca and tube feet. This result suggests that the RGP gene is transcribed mainly in the radial nerves of A. pectinifera. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. 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

  8. Involvement of glutathione, sulfhydryl compounds, nitric oxide, vasoactive intestinal peptide, and heat-shock protein-70 in the gastroprotective mechanism of Croton cajucara Benth. (Euphorbiaceae) essential oil.

    PubMed

    Rozza, Ariane Leite; de Mello Moraes, Thiago; Kushima, Hélio; Nunes, Domingos Sávio; Hiruma-Lima, Clélia Akiko; Pellizzon, Cláudia Helena

    2011-09-01

    This study aimed to evaluate the gastroprotective mechanism of action of the essential oil of Croton cajucara Benth. (Euphorbiaceae) stem bark in ethanol-induced gastric ulcers and its in vitro anti-Helicobacter pylori activity. The involvement of heat-shock protein-70, vasoactive intestinal peptide, glutathione, nitric oxide, and nonprotein sulfhydryl compounds in the gastroprotective effect was determined in male Wistar rats. The minimum inhibitory concentration against H. pylori was determined in vitro. The results were analyzed by analysis of variance followed by the Dunnett test, and a P value less than 0.05 was considered to represent a statistically significant difference. C. cajucara decreased ethanol-induced ulcer area in 100% of ulcers and decreased the histologic lesions. In the C. cajucara group, the area marked by heat-shock protein-70 was significantly higher than the area in the control group; this finding was not seen for vasoactive intestinal peptide. C. cajucara could not maintain glutathione levels close to those in the sham group. The gastric ulcer area of rats treated with the sulfhydryl compound blocker was decreased, but the ulcer area of rats treated with nitric oxide synthase inhibitor showed no alteration. The minimum inhibitory concentration obtained for C. cajucara was 125 μg/mL. These findings suggest that sulfhydryl compounds and heat-shock protein-70, but not nitric oxide, glutathione, or vasoactive intestinal peptide, are involved in the C. cajucara gastroprotective effect against ethanol-induced gastric ulcers.

  9. A safety and pharmacokinetic dosing study of glucagon-like peptide 2 in infants with intestinal failure.

    PubMed

    Sigalet, David L; Brindle, Mary E; Boctor, Dana; Dicken, Bryan; Lam, Viona; Lu, Lily Sia; de Heuvel, Elaine; Hartmann, Bolette; Holst, Jens J

    2017-05-01

    Glucagon-like peptide 2 (GLP-2) analogues are approved for adults with intestinal failure (IF), but no studies have included infants. This study examined the pharmacokinetics (PK), safety, and nutritional effects of GLP-2 in infants with IF. With parental consent (Health Canada Protocol:150,979), parenteral nutrition (PN)-dependent infants were treated with 5-20-μg/kg/day GLP-2 for 3days (phase 1), and if tolerated continued for 42days (phase 2). Nutritional therapy was by primary caregivers, and follow-up was to one year. Six patients were enrolled, age 5.4±3.2months, bowel length: 27±12% of predicted, PN dependent (67±18% of calories). GLP-2 did not affect vital signs, nor were there significant adverse events during the trial. Dosing 5μg/kg/day gave GLP-2 levels of 52-57pmol/L, with no change in half-life or endogenous GLP-2 levels. Enteral feeds, weight, Z scores, stooling frequency, and citrulline levels improved numerically. The trial was discontinued early because of a drop in potency. GLP-2 was well tolerated in infants, and pK was similar to children with no changes in endogenous GLP-2 release. The findings suggest that GLP-2 ligands may be safely used in infants and may have beneficial effects on nutritional status. Further study is required. 2b Prospective Interventional Study. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Enhanced Mortality to Metastatic Bladder Cancer Cell Line MB49 in Vasoactive Intestinal Peptide Gene Knockout Mice

    PubMed Central

    Mirsaidi, Niely; Burns, Matthew P.; McClain, Steve A.; Forsyth, Edward; Li, Jonathan; Dukes, Brittany; Lin, David; Nahvi, Roxanna; Giraldo, Jheison; Patton, Megan; Wang, Ping; Lin, Ke; Miller, Edmund; Ratliff, Timothy; Hamidi, Sayyed; Crist, Scott; Takemaru, Ken-Ichi; Szema, Anthony

    2017-01-01

    To identify if the absence of the vasoactive intestinal peptide (VIP) gene enhances susceptibility to death from metastatic bladder cancer, two strains of mice were injected with MB49 murine bladder cancer cells. The growth and spread of the cancer was measured over a period of 4 weeks in C57BL/6 mice and 5 weeks in VIP knockout (KO) mice. A Kaplan–Meier plot was constructed to compare control C57BL/6 mice and C57BL/6 mice with MB49 vs. VIP KO controls and VIP KO mice with MB49. The wild-type (WT) strain (C57BL/6) contained the VIP gene, while the other strain, VIP knockout backcrossed to C57BL/6 (VIP KO) did not and was thus unable to endogenously produce VIP. VIP KO mice had increased mortality compared to C57BL/6 mice at 4 weeks. The number of ulcers between both groups was not statistically significant. In vitro studies indicated that the presence VIP in high doses reduced MB49 cell growth, as well as macrophage inhibitory factor (MIF), a growth factor in bladder cancer cells. These findings support the concept that VIP may attenuate susceptibility to death from bladder cancer, and that it exerts its effect via downregulation of MIF. PMID:28824540

  11. 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.

  12. 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.

  13. The disodium salt of EDTA inhibits the binding of vasoactive intestinal peptide to macrophage membranes: endodontic implications.

    PubMed

    Segura, J J; Calvo, J R; Guerrero, J M; Sampedro, C; Jimenez, A; Llamas, R

    1996-07-01

    The purpose of this study was to investigate the effect of the disodium salt of ethylenediamine tetraacetate (EDTA), a calcium ion chelator used in the root canal therapy, on vasoactive intestinal peptide (VIP) binding to macrophage membranes (MM's). Binding assays were conducted at 15 degrees C in 0.5 ml of 50 mM Tris-HCl buffer (pH 7.5) containing 1.6% (w/v) bovine serum albumin, 1.2 mg/ml of bacitracin, and different EDTA concentrations, using 45 pM of [125I]VIP as tracer. Results showed that EDTA inhibits VIP binding to MM's in a dose-dependent manner, with an IC50 value of 5.4 mM (p < 0.01). EDTA concentrations equal or higher than 100 mM of abolished VIP-MM interaction. Taking into account that the macrophage plays an essential role in inflammatory reactions and the immune response, we conclude that the apical extrusion of EDTA during root canal therapy could modify VIP-macrophage interaction modulating the inflammatory mechanisms involved in periapical lesions.

  14. Distribution of vasotocin- and vasoactive intestinal peptide-like immunoreactivity in the brain of blue tit (Cyanistes coeruleus)

    PubMed Central

    Montagnese, Catherine M.; Székely, Tamás; Csillag, András; Zachar, Gergely

    2015-01-01

    Blue tits (Cyanistes coeruleus) are songbirds, used as model animals in numerous studies covering a wide field of research. Nevertheless, the distribution of neuropeptides in the brain of this avian species remains largely unknown. Here we present some of the first results on distribution of Vasotocine (AVT) and Vasoactive intestinal peptide (VIP) in the brain of males and females of this songbird species, using immunohistochemistry mapping. The bulk of AVT-like cells are found in the hypothalamic supraoptic, paraventricular and suprachiasmatic nuclei, bed nucleus of the stria terminalis, and along the lateral forebrain bundle. Most AVT-like fibers course toward the median eminence, some reaching the arcopallium, and lateral septum. Further terminal fields occur in the dorsal thalamus, ventral tegmental area and pretectal area. Most VIP-like cells are in the lateral septal organ and arcuate nucleus. VIP-like fibers are distributed extensively in the hypothalamus, preoptic area, lateral septum, diagonal band of Broca. They are also found in the bed nucleus of the stria terminalis, amygdaloid nucleus of taenia, robust nucleus of the arcopallium, caudo-ventral hyperpallium, nucleus accumbens and the brainstem. Taken together, these results suggest that both AVT and VIP immunoreactive structures show similar distribution to other avian species, emphasizing evolutionary conservatism in the history of vertebrates. The current study may enable future investigation into the localization of AVT and VIP, in relation to behavioral and ecological traits in the brain of tit species. PMID:26236200

  15. The effect of vasoactive intestinal peptide on development of form deprivation myopia in the chick: a pharmacological and immunocytochemical study.

    PubMed

    Seltner, R L; Stell, W K

    1995-05-01

    The role of vasoactive intestinal peptide (VIP) in the development of form deprivation myopia (FDM) was examined. Daily intravitreal injection of porcine VIP reduced, but did not eliminate FDM at a maximal daily dose of 1 x 10(-5) mol/injection. A VIP analogue reported to be relatively hydrolysis-resistant in vivo, had no effect on development of FDM at any dose tested. Two VIP antagonists completely abolished FDM. The one reported to be selective for central nervous system VIP receptors was 100 times more potent than one reported to be selective for peripheral nervous system receptors (ED50 = 2 x 10(-10) and 2 x 10(-8) mol/injection respectively). By immunofluorescence using antiserum to porcine VIP, VIP-like immunoreactivity was localized to a subset of amacrine cells (AC) and in three parallel layers in the inner plexiform layer (IPL) (10%, 40% and 70% of IPL thickness from the AC layer). Immunoreactive nerve fibres were also seen in the choroid, the ciliary body and the iris. These results suggest that VIP may play a role in both normal development of the refractive properties of the eye, and in the development of FDM.

  16. A comparison of the ventilatory, cardiovascular and metabolic effects of salbutamol, aminophylline and vasoactive intestinal peptide in normal subjects.

    PubMed Central

    Morice, A H; Schofield, P; Keal, E E; Sever, P S

    1986-01-01

    Intravenous infusion of placebo for 30 min followed by either salbutamol 10 micrograms min-1, aminophylline 0.2 mg kg-1 min-1 or vasoactive intestinal peptide (VIP) 6 pmol kg-1 min-1 for 30 min was performed in a single blind fashion in six normal volunteers. Both salbutamol and aminophylline increased minute ventilation, (P less than 0.05) the mean increase being 26% and 19% respectively. Aminophylline also increased the ventilatory response to carbon dioxide by 47% (P less than 0.05) when measured by hyperoxic rebreathing, whereas salbutamol and VIP were without significant effect. All three drugs caused a tachycardia, mean increase in the pulse being 16, 8 and 2 beats min-1 for salbutamol, aminophylline and VIP respectively, and aminophylline also increased both systolic and diastolic blood pressure, mean arterial pressure increasing by 14 mmHg. VIP caused haemoconcentration and salbutamol the expected changes in plasma biochemistry. Plasma catecholamines increased slightly during drug infusion, although this effect is unlikely to be important. PMID:3756064

  17. Differences and significance of motilin, vasoactive intestinal peptide and gastrin in blood and gallbladder tissues of patients with gallstones.

    PubMed

    Zhang, Zhen-Hai; Wu, Shuo-Dong; Su, Yang; Jin, Jun-Zhe; Fan, Ying; Yu, Hong; Zhang, Li-Kui

    2008-02-01

    The disorders of gallbladder motility may play an important role in the formation of gallstones. Many neural and hormonal factors and their interactions regulate gallbladder motility and bile flow into the duodenum. Further study in these factors may help to reveal the etiology of gallbladder diseases. This study was undertaken to assess the relationship of the levels of motilin, vasoactive intestinal peptide (VIP) and gastrin in blood and gallbladder tissues with the formation of cholelithiasis. The levels of motilin, gastrin and VIP in blood and gallbladder tissues of 36 patients with gallbladder stones, 14 patients with gallbladder polyps, 10 healthy volunteers and 10 patients with common bile duct stones were measured by radioimmunoassay. The level of motilin in plasma and gallbladder tissues of the gallbladder stone group was higher than that of the control and gallbladder polyp groups (P<0.05). The levels of plasma VIP and serum gastrin were much higher than those of the other three groups (P<0.01). The level of VIP in gallbladder tissues was higher than that of the control and gallbladder polyp groups (P<0.01). The abnormal excretion of hormonal factors is closely related to gallstone formation. The high level of VIP in gallbladder tissues may be an important cause of gallbladder hypomotility. The abnormal level of serum gastrin may be related to the gastrointestinal symptoms of patients with gallstones.

  18. Vasoactive intestinal peptide-induced neuritogenesis in neuroblastoma SH-SY5Y cells involves SNAP-25.

    PubMed

    Héraud, Céline; Chevrier, Lucie; Meunier, Annie Claire; Muller, Jean-Marc; Chadéneau, Corinne

    2008-01-01

    Vasoactive intestinal peptide (VIP) is a neuropeptide known to regulate proliferation and differentiation in normal and tumoral cells. We previously reported that VIP induced neuritogenesis in human neuroblastoma SH-SY5Y cells cultured in serum-free medium. This neuritogenesis was associated with a regulated expression of neuronal cytoskeleton markers. To further characterize the neuroblastic cell differentiation induced by VIP in human SH-SY5Y cells, we investigated expression of synaptosomal-associated protein of 25 kDa (SNAP-25), a protein implicated in exocytosis associated with different processes, including neurite outgrowth. Western immunoblotting and real-time RT-PCR analyses revealed that VIP increased expression of the SNAP-25 protein and the level of both SNAP-25a and SNAP-25b mRNA isoforms. Immunofluorescence experiments indicated that SNAP-25 was mainly located in neurites and at the plasma membrane in SH-SY5Y cells treated with VIP. RNA interference experiments demonstrated that SNAP-25 was involved in VIP-induced neuritogenesis. In conclusion, SNAP-25 is up-regulated and implicated in neuritogenesis in human neuroblastoma SH-SY5Y cells treated with the neuropeptide VIP.

  19. 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

  20. Vasoactive intestinal peptide antagonist treatment during mouse embryogenesis impairs social behavior and cognitive function of adult male offspring.

    PubMed

    Hill, Joanna M; Cuasay, Katrina; Abebe, Daniel T

    2007-07-01

    Vasoactive intestinal peptide (VIP) is a regulator of rodent embryogenesis during the period of neural tube closure. VIP enhanced growth in whole cultured mouse embryos; treatment with a VIP antagonist during embryogenesis inhibited growth and development. VIP antagonist treatment during embryogenesis also had permanent effects on adult brain chemistry and impaired social recognition behavior in adult male mice. The neurological deficits of autism appear to be initiated during neural tube closure and social behavior deficits are among the key characteristics of this disorder that is more common in males and is frequently accompanied by mental retardation. The current study examined the blockage of VIP during embryogenesis as a model for the behavioral deficits of autism. Treatment of pregnant mice with a VIP antagonist during embryonic days 8 through 10 had no apparent effect on the general health or sensory or motor capabilities of adult offspring. However, male offspring exhibited reduced sociability in the social approach task and deficits in cognitive function, as assessed through cued and contextual fear conditioning. Female offspring did not show these deficiencies. These results suggest that this paradigm has usefulness as a mouse model for aspects of autism as it selectively impairs male offspring who exhibit the reduced social behavior and cognitive dysfunction seen in autism. Furthermore, the study indicates that the foundations of some aspects of social behavior are laid down early in mouse embryogenesis, are regulated in a sex specific manner and that interference with embryonic regulators such as VIP can have permanent effects on adult social behavior.

  1. Anatomical distribution of vasoactive intestinal peptide binding sites in peripheral tissues investigated by in vitro autoradiography.

    PubMed

    Power, R F; Bishop, A E; Wharton, J; Inyama, C O; Jackson, R H; Bloom, S R; Polak, J M

    1988-01-01

    Vasoactive intestinal polypeptide has a widespread distribution in the body, occurring in both the central and peripheral nervous systems and considerable information is available on its distribution, physiology, and pharmacological actions. Receptors for VIP have been demonstrated previously in peripheral tissues by conventional binding techniques using isolated membrane preparations. However, information on their precise localization is limited. We therefore localized binding sites in a variety of guinea pig and rat tissues by in vitro autoradiography and made a parallel study of the distribution of VIP nerves in these tissues using immunocytochemistry. [125I]VIP was prepared by the chloramine T method and shown to be pharmacologically active. After a preincubation procedure to remove endogenously bound VIP, unfixed cryostat sections were incubated with 1 nM [125I]VIP. To determine specific binding, sections were incubated in the presence or absence of 1 microM unlabeled VIP. Autoradiograms were generated by exposing the sections to LKB-Ultrofilm or emulsion-coated coverslips. Dense binding occurred in discrete locations within the gastrointestinal, respiratory, and genital tracts, correlating with known actions of VIP and, to various extents, with the distribution of VIP nerves. For example, there was precise localization to respiratory epithelium, smooth muscle of airways and blood vessels, and alveolar walls, in keeping with the effects of VIP on vascular and airway smooth muscle and mucus secretion.

  2. The activity of the rectal gland of the North Pacific spiny dogfish Squalus suckleyi is glucose dependent and stimulated by glucagon-like peptide-1.

    PubMed

    Deck, Courtney A; Anderson, W Gary; Conlon, J Michael; Walsh, Patrick J

    2017-04-25

    Elasmobranchs possess a specialised organ, the rectal gland, which is responsible for excreting sodium chloride via the posterior intestine. Previous work has indicated that the gland may be activated by a number of hormones, some of which are likely related to the salt or volume loads associated with feeding. Furthermore, evidence exists for the gland being glucose dependent which is atypical for an elasmobranch tissue. In this study, the presence of sodium-glucose co-transporters (SGLTs) in the rectal gland and their regulation by feeding were investigated. In addition, the hypothesis of glucose dependence was examined through the use of glucose transporter (GLUT and SGLT) inhibitors, phlorizin, Indinavir, and STF-31 and their effect on secretion by the rectal gland. Finally, the effects on rectal gland activity of insulin, glucagon, and glucagon-like peptide-1, hormones typically involved in glucoregulation, were examined. The results showed that sglt1 mRNA is present in the gland, and there was a significant reduction in sglt1 transcript abundance 24 h post-feeding. An almost complete suppression of chloride secretion was observed when glucose uptake was inhibited, confirming the organ's glucose dependence. Finally, perfusion with dogfish GLP-1 (10 nmol L(-1)), but not dogfish glucagon, was shown to markedly stimulate the activity of the gland, increasing chloride secretion rates above baseline by approximately 16-fold (p < 0.001). As GLP-1 is released from the intestine upon feeding, we propose that this may be the primary signal for activation of the rectal gland post-feeding.

  3. 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

  4. 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

  5. Glucagon-like peptide-1 receptor stimulation increases GFR and suppresses proximal reabsorption in the rat.

    PubMed

    Thomson, Scott C; Kashkouli, Ali; Singh, Prabhleen

    2013-01-15

    The incretin hormone glucagon-like peptide-1 (GLP-1) is released from the gut in response to fat or carbohydrate and contributes to negative feedback control of blood glucose by stimulating insulin secretion, inhibiting glucagon, and slowing gastric emptying. GLP-1 receptors (GLP-1R) are also expressed in the proximal tubule, and possibly elsewhere in the kidney. Presently, we examined the effect of a GLP-1R agonist on single-nephron glomerular filtration rate (GFR; SNGFR), proximal reabsorption (Jprox), tubuloglomerular feedback (TGF) responses, and urine flow rate in hydropenic male Wistar and Wistar-Froemter rats. Micropuncture and whole-kidney data were obtained before and during infusion of the GLP-1 agonist exenatide (1 nmol/h iv). SNGFR and Jprox were measured by late proximal collection at both extremes of TGF activation, which was achieved by perfusing Henle's loop at 0 or 50 nl/min. Primary changes in Jprox were revealed by analysis of covariance for Jprox with SNGFR as a covariate. Effects on TGF activation were determined in a separate set of experiments by comparing early distal and late proximal collections. Exenatide increased SNGFR by 33-50%, suppressed proximal tubular reabsorption by 20-40%, doubled early distal flow rate, and increased urine flow rate sixfold without altering the efficiency of glomerulotubular balance, TGF responsiveness, or the tonic influence of TGF. This implies that exenatide is both a proximal diuretic and a renal vasodilator. Since the natural agonist for the GLP-1R is regulated by intake of fat and carbohydrate, but not by salt or fluid, the control of salt excretion by the GLP-1R system departs from the usual negative-feedback paradigm for regulating salt balance.

  6. 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.

  7. 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

  8. 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.

  9. Posttranslational alanine trans-stimulation of zwitterionic amino acid transport systems in human intestinal Caco-2 cells.

    PubMed

    Pan, Ming; Souba, Wiley W; Wolfgang, Christopher L; Karinch, Anne M; Stevens, Bruce R

    2002-05-01

    Neutral dietary amino acids, such as alanine, are transported across the gut lumen by both Na(+)-dependent (System B) and Na(+)-independent (System L) carriers, but the nature of the acute phase of substrate-induced uptake is unknown. This study examined the effects of acute amino acid substrate exposure on the rapid modulation of apical membrane alanine transport in cultured human intestinal cells. System B and System L transport activity kinetics, as well as ATB(0) mRNA levels, were measured in confluent Caco-2 monolayers treated with various metabolic agents during short-term and extended time periods. Depleting the incubation medium of alanine attenuated both System B and System L uptake activities within 30 mins, with a complete return to baseline values within 3 h. Extracellular alanine added to depleted Caco-2 cells rapidly (within 5 min) increased alanine transport activities. Kinetic analysis showed that acute alanine exposure increased both K(m) and V(max) of each transport system, indicative of a trans-stimulation effect. Augmenting intracellular alanine levels using the cytosolic alanine aminotransferase inhibitor, aminooxyacetic acid, increased alanine uptake activity. Acute exposure to other substrates of Systems B and L also increased the uptake of alanine, while nonsubstrates did not affect alanine uptake. Cycloheximide or actinomycin did not affect substrate acute activation of System B, and the steady-state level of ATB(0) mRNA was not altered by amino acid exposure. Increasing alanine availability to intestinal cells, by either exogenous substrate exposure or inhibition of intracellular catabolism, acutely and reversibly increases apical membrane alanine transport activity via a posttranslation trans-stimulation mechanism.

  10. 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.

  11. 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.

  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. 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

  14. Importance of Large Intestine in Regulating Bile Acids and Glucagon-Like Peptide-1 in Germ-Free Mice

    PubMed Central

    Selwyn, Felcy Pavithra; Csanaky, Iván L.; Zhang, Youcai

    2015-01-01

    It is known that 1) elevated serum bile acids (BAs) are associated with decreased body weight, 2) elevated glucagon-like peptide-1 (GLP-1) levels can decrease body weight, and 3) germ-free (GF) mice are resistant to diet-induced obesity. The purpose of this study was to test the hypothesis that a lack of intestinal microbiota results in more BAs in the body, resulting in increased BA-mediated transmembrane G protein–coupled receptor 5 (TGR5) signaling and increased serum GLP-1 as a mechanism of resistance of GF mice to diet-induced obesity. GF mice had 2- to 4-fold increased total BAs in the serum, liver, bile, and ileum. Fecal excretion of BAs was 63% less in GF mice. GF mice had decreased secondary BAs and increased taurine-conjugated BAs, as anticipated. Surprisingly, there was an increase in non–12α-OH BAs, namely, β-muricholic acid, ursodeoxycholic acid (UDCA), and their taurine conjugates, in GF mice. Further, in vitro experiments confirmed that UDCA is a primary BA in mice. There were minimal changes in the mRNA of farnesoid X receptor target genes in the ileum (Fibroblast growth factor 15, small heterodimer protein, and ileal bile acid–binding protein), in the liver (small heterodimer protein, liver receptor homolog-1, and cytochrome P450 7a1), and BA transporters (apical sodium dependent bile acid transporter, organic solute transporter α, and organic solute transporter β) in the ileum of GF mice. Surprisingly, there were marked increases in BA transporters in the large intestine. Increased GLP-1 levels and gallbladder size were observed in GF mice, suggesting activation of TGR5 signaling. In summary, the GF condition results in increased expression of BA transporters in the colon, resulting in 1) an increase in total BA concentrations in tissues, 2) a change in BA composition to favor an increase in non–12α-OH BAs, and 3) activation of TGR5 signaling with increased gallbladder size and GLP-1. PMID:26199423

  15. 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.

  16. 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.

  17. Ghrelin suppresses cholecystokinin (CCK), peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) in the intestine, and attenuates the anorectic effects of CCK, PYY and GLP-1 in goldfish (Carassius auratus).

    PubMed

    Blanco, Ayelén Melisa; Bertucci, Juan Ignacio; Valenciano, Ana Isabel; Delgado, María Jesús; Unniappan, Suraj

    2017-07-01

    Ghrelin is an important gut-derived hormone with an appetite stimulatory role, while most of the intestinal hormones, including cholecystokinin (CCK), peptide YY (PYY) and glucagon-like peptide-1 (GLP-1), are appetite-inhibitors. Whether these important peptides with opposing roles on food intake interact to regulate energy balance in fish is currently unknown. The aim of this study was to characterize the putative crosstalk between ghrelin and CCK, PYY and GLP-1 in goldfish (Carassius auratus). We first determined the localization of CCK, PYY and GLP-1 in relation to ghrelin and its main receptor GHS-R1a (growth hormone secretagogue 1a) in the goldfish intestine by immunohistochemistry. Colocalization of ghrelin/GHS-R1a and CCK/PYY/GLP-1 was found primarily in the luminal border of the intestinal mucosa. In an intestinal explant culture, a significant decrease in prepro-cck, prepro-pyy and proglucagon transcript levels was observed after 60min of incubation with ghrelin, which was abolished by preincubation with the GHS-R1a ghrelin receptor antagonist [D-Lys3]-GHRP-6 (except for proglucagon). The protein expression of PYY and GLP-1 was also downregulated by ghrelin. Finally, intraperitoneal co-administration of CCK, PYY or GLP-1 with ghrelin results in no modification of food intake in goldfish. Overall, results of the present study show for the first time in fish that ghrelin exerts repressive effects on enteric anorexigens. It is likely that these interactions mediate the stimulatory effects of ghrelin on feeding and metabolism in fish. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. 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.

  19. Effect of growth hormone releasing hormone (GHRH) and vasoactive intestinal peptide (VIP) on in vitro bovine oocyte maturation.

    PubMed

    Beker, A R; Izadyar, F; Colenbrander, B; Bevers, M M

    2000-06-01

    The aim of this study was to investigate the effects of growth hormone releasing hormone (GHRH) and the structural-related peptide vasoactive intestinal peptide (VIP) on nuclear maturation, cortical granule distribution and cumulus expansion of bovine oocytes. Bovine cumulus oocyte complexes (COCs) were cultured in M199 without FCS and gonadotropins and in the presence of either 100 ng/mL bovine GHRH or 100 ng/mL porcine VIP. The COCs were incubated at 39 degrees C in a humidified atmosphere with 5% CO2 in air, and the nuclear stage was assessed after 16 or 24 h of incubation using DAPI staining. Cortical granule distribution was assessed after 24 h of incubation using FITC-PNA staining. To assess the effects of GHRH and VIP on cumulus expansion, COCs were incubated for 24 h under the conditions described above. In addition, 0.05 IU/mL recombinant human FSH was added to GHRH and VIP groups. Cultures without GHRH/VIP/FSH or with only FSH served as negative and positive controls, respectively. At 16 h neither GHRH (42.9%) nor VIP (38.5%) influenced the percentage of MII stage oocytes compared with their respective controls (44.2 and 40.8%). At 24 h there also was no difference in the percentage of MII oocytes between GHRH (77.0%), VIP (75.3%) and their respective controls (76.0 and 72%). There was no significant cumulus expansion in the GHRH or VIP group, while FSH induced significant cumulus expansion compared with the control groups, which were not inhibited by GHRH or VIP. Distribution of cortical granules was negatively affected by GHRH and VIP. The percentage of oocytes showing more or less evenly dispersed cortical granules in the cortical cytoplasm aligning the oolemma (Type 3) was lower in the GHRH (2.7%) and VIP (7.8%) groups than in the control group (15.9%). In conclusion, GHRH and VIP have no effect on nuclear maturation or cumulus expansion of bovine COCs but retard cytoplasmic maturation, as reflected by delayed cortical granule migration.

  20. Altered vasoactive intestinal peptides expression in irritable bowel syndrome patients and rats with trinitrobenzene sulfonic acid-induced colitis.

    PubMed

    Del Valle-Pinero, Arseima Y; Sherwin, LeeAnne B; Anderson, Ethan M; Caudle, Robert M; Henderson, Wendy A

    2015-01-07

    To investigate the vasoactive intestinal peptides (VIP) expression in irritable bowel syndrome (IBS) and trinitrobenzene sulfonic acid (TNBS) induced colitis. The VIP gene expression and protein plasma levels were measured in adult participants (45.8% male) who met Rome III criteria for IBS for longer than 6 mo and in a rat model of colitis as induced by TNBS. Plasma and colons were collected from naïve and inflamed rats. Markers assessing inflammation (i.e., weight changes and myeloperoxidase levels) were assessed on days 2, 7, 14 and 28 and compared to controls. Visceral hypersensitivity of the rats was assessed with colo-rectal distension and mechanical threshold testing on hind paws. IBS patients (n = 12) were age, gender, race, and BMI-matched with healthy controls (n = 12). Peripheral whole blood and plasma from fasting participants was collected and VIP plasma levels were assayed using a VIP peptide-enzyme immunoassay. Human gene expression of VIP was analyzed using a custom PCR array. TNBS induced colitis in the rats was confirmed with weight loss (13.7 ± 3.2 g) and increased myeloperoxidase activity. Visceral hypersensitivity to colo-rectal distension was increased in TNBS treated rats up to 21 d and resolved by day 28. Somatic hypersensitivity was also increased up to 14 d post TNBS induction of colitis. The expression of an inflammatory marker myeloperoxidase was significantly elevated in the intracellular granules of neutrophils in rat models following TNBS treatment compared to naïve rats. This confirmed the induction of inflammation in rats following TNBS treatment. VIP plasma concentration was significantly increased in rats following TNBS treatment as compared to naïve animals (P < 0.05). Likewise, the VIP gene expression from peripheral whole blood was significantly upregulated by 2.91-fold in IBS patients when compared to controls (P < 0.00001; 95%CI). VIP plasma protein was not significantly different when compared with controls (P = 0

  1. Rapid Upregulation of Sodium-Glucose Transporter SGLT1 in Response to Intestinal Sweet Taste Stimulation

    PubMed Central

    Stearns, Adam T.; Balakrishnan, Anita; Rhoads, David B.; Tavakkolizadeh, Ali

    2014-01-01

    Objective We set out to examine the short-term regulation of the intestinal sodium/glucose cotransporter SGLT1 by its substrate glucose and sweet taste analogs. Summary Background Data Intestinal SGLT1 is a putative target for antidiabetic therapy; however, its physiological regulation is incompletely understood, limiting its application as a pharmacological target. While it is clearly regulated by dietary composition over a period of days, its short-term regulation by nutrients is unknown. Methods Sprague-Dawley rats were anesthetized, and the duodenum cannulated. D-glucose, D-fructose, saccharin, D-mannitol, and water were infused for 3 hours, before harvest of proximal jejunum for SGLT1 analysis with Western blotting and quantitative polymerase chain reaction. In further experiments, the receptor region was identified by D-glucose infusion of isolated regions. Lastly, the vagus was de-afferented with capsaicin, and 5HT3-receptor activation of vagal afferents inhibited using ondansetron, before repeating experiments using water or D-glucose infusion. Results Infusion of D-glucose led to 2.9-fold up-regulation in SGLT1 compared with water or iso-osmotic D-mannitol; this effect was replicated by D-fructose or saccharin. This response was strongest following isolated infusions of duodenum and proximal jejunum, with a blunted effect distally; topography matched the expression profile of sweet taste receptor T1R2/T1R3. The reflex was abolished by capsaicin pretreatment, and blunted by ondansetron. Conclusions The agonist response implicates the luminal-based sweet-taste receptor T1R2/T1R3, with the reflex apparently involving vagal afferents. The proximal nature of the sensor coincides with the excluded biliopancreatic limb in Roux-en-Y gastric bypass, and this may provide a novel explanation for the antidiabetic effect of this procedure. PMID:20395849

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. Influence of inositol hexaphosphate on the expression of selected proliferation markers in IL-1β-stimulated intestinal epithelial cells.

    PubMed

    Kapral, Małgorzata; Sośnicki, Stanisław; Wawszczyk, Joanna; Węglarz, Ludmiła

    2014-01-01

    The aim of the present study was to examine the influence of IP6, a naturally occurring phytochem- ical, on the expression of genes coding for proliferation markers, i.e., cyclin D1 (CCND1) and histone H3 in IL-1β-stimulated intestinal cancer cell line Caco-2. Quantification of genes expression was carried out using real time RT-QPCR technique in Caco-2 cells after treatment with IL-1β, 1 and 2.5 mM of IP6 for 3, 6 and 12 h. In separate cultures, cells were incubated with IL-1β for the indicated times. The untreated Caco-2 cells were used as the control. In a time course experiment, stimulation of cells with IL-1β only resulted in an overex- pression of both CCND1 and histone H3 mRNAs as compared with control. IP6 had no influence on IL-1β-stimulated CCND1 expression for 3 and 6 h. After 12 h, statistically significant decrease in CCND1 mRNA was observed in cells exposed to IL-1β and IP6 (1 and 2.5 mM) in relation to cells treated with IL-1β only. The levels of H3 mRNA in IL-1β-stimulated cells and cells treated with IL-1β and IP6 revealed no statistically significant differences after 3 h. IP6 at 1 and 2.5 mM enhanced IL1β-stimulated transcription of H3 gene after 6 h. Subsequently (12 h), the combination of IP6 and IL-1β decreased H3 mRNA level compared to IL1β-treated cells. In conclusion, pro-inflammatory cytokine IL-1β up-regulates CCND1 and histone H3 mRNAs expression in Caco-2 cells. These results suggest that the ability of IP6 to inhibit colon cancer cells proliferation may be mediated through downregulation of genes encoding cyclin D1 and histone H3 at the mRNA level.

  8. A Transcriptionally Permissive Epigenetic Landscape at the Vasoactive Intestinal Peptide Receptor-1 Promoter Suggests an Euchromatin Nuclear Position in Murine CD4 T Cells

    PubMed Central

    Benton, K.D.; Hermann, R.J.; Vomhof-DeKrey, E.E.; Haring, J.S.; Van der Steen, T.; Smith, J; Dovat, S; Dorsam, G.P.

    2009-01-01

    Summary T cells express receptors for neuropeptides that mediate immunological activities. Vasoactive intestinal peptide receptor – 1 (VPAC1), the prototypical group II G protein coupled receptor, binds two neuropeptides with high affinity, called vasoactive intestinal peptide and pituitary adenylate cyclase activating peptide. During T cell signaling, VPAC1 mRNA expression levels are significantly downregulated through a Src kinase dependent mechanism, thus altering the sensitivity for these neuropeptides during an immune reaction. Presently, it is unknown whether the mechanism that regulates VPAC1 during T cell signaling involves epigenetic changes. Therefore, we hypothesized that the epigenetic landscape consisting of diacetylation at H3K9/14 and trimethylation at H3K4, two transcriptionally permissive histone modifications, would parallel VPAC1 expression showing high enrichment in untreated T cells, but lower enrichment in α-CD3 treated T cells. To this end, quantitative chromatin immunoprecipitation (ChIP) analysis of H3K9/14ac and H3K4me3 was conducted using purified CD4+ T cells, with CD45R+ B cells as a negative control. Our data revealed that these histone modifications at the VPAC1 promoter did indeed parallel its mRNA levels between T and B lymphocytes, but did not decrease during T cell signaling. Collectively, these data strongly imply a euchromatin nuclear position for the VPAC1 locus irrespective of the activation status of T cells. PMID:19729043

  9. 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

  10. Proteolytic degradation and deactivation of amphibian skin peptides obtained by electrical stimulation of their dorsal glands.

    PubMed

    Samgina, Tatiana Yu; Tolpina, Miriam I; Hakalehto, Elias; Artemenko, Konstantin A; Bergquist, Jonas; Lebedev, Albert T

    2016-05-01

    Amphibians are among the oldest creatures on our planet. Their only defensive weapon efficient against microorganisms and predators involves their skin secretion. The wide range of biological activities of the peptides in the skin secretion of amphibians makes these compounds rather interesting for generation of prospective pharmaceuticals. The first step in studying these molecules requires their structures to be established. Mass spectrometry is the most powerful tool for this purpose. The sampling and sample preparation stages preceding mass spectrometry experiments appear to be rather crucial. The results obtained here demonstrate that these preparation procedures might lead to partial or complete loss of the bioactive peptides in the secretion. Five minutes in water was enough to completely destroy all of the bioactive peptides in the skin secretion of the marsh frog (Rana ridibunda); even immediate addition of methanol to the water solution of the peptides did not prevent partial destruction. Concerted effort should be directed towards development of the most efficient procedure to keep the secreted peptides intact. Graphical Abstract ᅟ.

  11. 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.

  12. A New Model of Reverse Cholesterol Transport: EnTICEing Strategies to Stimulate Intestinal Cholesterol Excretion

    PubMed Central

    Temel, Ryan E.; Brown, J. Mark

    2015-01-01

    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. PMID:25930707

  13. Amphipathic variable region heavy chain peptides derived from monoclonal human Wegener's anti-PR3 antibodies stimulate lymphocytes from patients with Wegener's granulomatosis and microscopic polyangiitis

    PubMed Central

    Peen, E; Malone, C; Myers, C; Williams, R C; Peck, A B; Csernok, E; Gross, W L; Staud, R

    2001-01-01

    Amphipathic variable-region heavy chain 11-mer peptides from monoclonal human IgM antiproteinase-3 antibodies were studied for peripheral blood lymphocyte stimulation in 21 patients with Wegener's granulomatosis (WG) or microscopic polyangiitis (MPA), connective tissue disease controls and normal control subjects. Positive T-cell activation was observed in most experiments with WG patients' lymphocytes using amphipathic VH-region peptides from four different human monoclonal anti-PR3 antibodies. Control peptides of the same length but without amphipathic characteristics along with other amphipathic peptides not derived from monoclonal anti-PR3 sequence were employed as controls. No significant lymphocyte stimulation was observed with normal controls, but positive stimulation with amphipathic VH peptides was also recorded in other connective tissue disease controls mainly patients with rheumatoid arthritis. Amphipathic peptides not derived from anti-PR3 sequence did not stimulate WG lymphocytes. Our findings indicate that lymphocyte reactivity as an element of cell-mediated immunity may be activated by amphipathic VH-region amino acid sequences of autoantibodies which are themselves associated with diseases such as WG. PMID:11529926

  14. Shiga Toxins Stimulate Secretion of Interleukin-8 from Intestinal Epithelial Cells

    PubMed Central

    Thorpe, C. M.; Hurley, Bryan P.; Lincicome, Lisa L.; Jacewicz, Mary S.; Keusch, Gerald T.; Acheson, David W. K.

    1999-01-01

    synthesis from intestinal epithelial cells could be important in augmenting the host mucosal inflammatory response to STEC infection. PMID:10531258

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. The difference in sensitivity to cardiac steriods of (Na+ + K+)-stimulated ATPase and amino acid transport in the intestinal mucosa of the rat and other species

    PubMed Central

    Robinson, J. W. L.

    1970-01-01

    1. The effect of various cardioactive steroids on the activity of a microsomal (Na+ + K+)-activated ATPase from rat intestinal mucosa has been studied and compared with their effects on L-phenylalanine and D-galactose transport by rings of rat intestine in vitro. A similar comparison between the sensitivities to ouabain of microsomal (Na+ + K+)-ATPase and of phenylalanine transport in the intestines of the mouse, guinea-pig and toad has been made. 2. The rat intestinal enzyme is 50% inhibited by a concentration of 1 × 10-4M ouabain, 1 × 10-5M scillaren A and 4 × 10-6M scilliroside. At concentrations which almost completely inhibit the (Na+ + K+)-ATPase activity, these steroids have no effect on the transport of phenylalanine or galactose by the rat intestine. Only at concentrations of 1 × 10-3M are scillaren A and scilliroside able to reduce phenylalanine accumulation significantly, the same concentration of ouabain being effective only in the absence of external potassium ions. Digitoxin, 1 × 10-4M, a comparatively apolar glycoside, had no action on phenylalanine transport in the rat intestine. 3. The effect of ouabain on the (Na+ + K+)-ATPase and phenylalanine transport system in the mouse intestine is completely analogous to its effect on these parameters in the rat. 4. A half-maximal inhibition of guinea-pig intestinal (Na+ + K+)-ATPase by ouabain occurs at an inhibitor concentration of 2 × 10-6M, but phenylalanine transport by this tissue is only half-maximally reduced at a concentration of 3 × 10-5M. Similarly, in the rabbit intestine, there appears to be a difference of an order of magnitude between the sensitivities of the two parameters. 5. In the toad, 50% inhibition of the enzymic activity is observed at a concentration of 3 × 10-5M ouabain, whereas a concentration of 8 × 10-4M is required to reduce phenylalanine accumulation by one half. 6. These findings are consistent with the suggestion that an (Na+ + K+)-stimulated ATPase is not the only

  20. 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. © 2017 Wiley Periodicals, Inc.

  1. 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 ...

  2. Inhibition of Competence Development, Horizontal Gene Transfer and Virulence in Streptococcus pneumoniae by a Modified Competence Stimulating Peptide

    PubMed Central

    Zhu, Luchang; Lau, Gee W.

    2011-01-01

    Competence stimulating peptide (CSP) is a 17-amino acid peptide pheromone secreted by Streptococcus pneumoniae. Upon binding of CSP to its membrane-associated receptor kinase ComD, a cascade of signaling events is initiated, leading to activation of the competence regulon by the response regulator ComE. Genes encoding proteins that are involved in DNA uptake and transformation, as well as virulence, are upregulated. Previous studies have shown that disruption of key components in the competence regulon inhibits DNA transformation and attenuates virulence. Thus, synthetic analogues that competitively inhibit CSPs may serve as attractive drugs to control pneumococcal infection and to reduce horizontal gene transfer during infection. We performed amino acid substitutions on conserved amino acid residues of CSP1 in an effort to disable DNA transformation and to attenuate the virulence of S. pneumoniae. One of the mutated peptides, CSP1-E1A, inhibited development of competence in DNA transformation by outcompeting CSP1 in time and concentration-dependent manners. CSP1-E1A reduced the expression of pneumococcal virulence factors choline binding protein D (CbpD) and autolysin A (LytA) in vitro, and significantly reduced mouse mortality after lung infection. Furthermore, CSP1-E1A attenuated the acquisition of an antibiotic resistance gene and a capsule gene in vivo. Finally, we demonstrated that the strategy of using a peptide inhibitor is applicable to other CSP subtype, including CSP2. CSP1-E1A and CSP2-E1A were able to cross inhibit the induction of competence and DNA transformation in pneumococcal strains with incompatible ComD subtypes. These results demonstrate the applicability of generating competitive analogues of CSPs as drugs to control horizontal transfer of antibiotic resistance and virulence genes, and to attenuate virulence during infection by S. pneumoniae. PMID:21909280

  3. Generating elastin-rich small intestinal submucosa-based smooth muscle constructs utilizing exogenous growth factors and cyclic mechanical stimulation.

    PubMed

    Heise, Rebecca Long; Ivanova, Julia; Parekh, Aron; Sacks, Michael S

    2009-12-01

    Successful approaches to tissue engineering smooth muscle tissues utilize biodegradable scaffolds seeded with autologous cells. One common problem in using biological scaffolds specifically is the difficulty of inducing cellular penetration and controlling de novo extracellular matrix deposition/remodeling in vitro. Our hypothesis was that small intestinal submucosa (SIS) exposed to specific mechanical stimulation regimes would modulate the synthesis of de novo collagen and elastin by bladder smooth muscle cells (BSMC) within the SIS matrix. We further hypothesized that the cytokines vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF-2), two key growth factors involved in epithelial mesenchymal signaling, will promote the cellular penetration into SIS necessary for mechanical stimulation. BSMC were seeded at 0.5 x 10(6) cells/cm(2) onto the luminal side of SIS specimens. VEGF (10 ng/mL) and FGF-2 (5 ng/mL) were added to each insert in the media every other day for up to 7 days in static culture. Following static culture, specimens were stretched strip-biaxially under 15% peak strain at either 0.5 or 0.1 Hz for an additional 7 days. Following the culture period, specimens were assayed histologically and biochemically for cellular penetration, proliferation, elastin, collagen, and protease activity. Histological analyses demonstrated that in standard culture media, BSMC remained on the surface of the SIS while both FGF-2 and VEGF profoundly promoted ingrowth of the BSMC into the SIS. The penetration of the cells in response to these cytokines was confirmed using a Transwell assay. Following cellular penetration, BSMC produced significant amounts of elastic fibers under cyclic mechanical stretching at 0.1 Hz under 15% stretch, as evidenced by colorimetric assay and histology using a Verhoeff-Van Gieson stain. Protease activity was assessed in the media and found to be statistically increased in static culture following FGF-2 treatment. These

  4. 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.

  5. 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

  6. Intra-Amniotic Administration (Gallus gallus) of Cicer arietinum and Lens culinaris Prebiotics Extracts and Duck Egg White Peptides Affects Calcium Status and Intestinal Functionality.

    PubMed

    Hou, Tao; Kolba, Nikolai; Glahn, Raymond P; Tako, Elad

    2017-07-21

    Calcium (Ca) is one of the most abundant inorganic elements in the human body and has many important physiological roles. Prebiotics and bioactive peptides are two important substances used to promote calcium uptake. However, the difference in mechanisms of the calcium uptake from these two supplements is not clear. By using the Gallus gallus model and the intra-amniotic administration procedure, the aim of this study was to investigate whether Ca status, intestinal functionality, and health-promoting bacterial populations were affected by prebiotics extracted from chickpea and lentil, and duck egg white peptides (DPs). Eleven groups (non-injected; 18 MΩ H₂O; 4 mmol/L CaCl₂; 50 mg/mL chickpea + 4 mmol/L CaCl₂; 50 mg/mL lentil + 4 mmol/L CaCl₂; 40 mg/mL DPs + 4 mmol/L CaCl₂; 5 mg/mL Val-Ser-Glu-Glu (VSEE) + 4 mmol/L CaCl₂; 50 mg/mL chickpea; 50 mg/mL lentil; 40 mg/mL DPs; 5 mg/mL VSEE) were utilized. Upon hatch, blood, cecum, small intestine, liver and bone were collected for assessment of serum bone alkaline phosphate level (BALP), the relative abundance of intestinal microflora, expression of Ca-related genes, brush border membrane (BBM) functional genes, and liver and bone mineral levels, respectively. The BALP level increased in the presence of lentil, DPs and VSEE (p < 0.05). The relative abundance of probiotics increased significantly (p < 0.05) by VSEE + Ca and chickpea. The expression of CalbindinD9k (Ca transporter) increased (p < 0.05) in Ca, chickpea + Ca and lentil + Ca groups. In addition, the brush border membrane functionality genes expressions increased (p < 0.05) by the chickpea or lentil extracts. Prebiotics and DPs beneficially affected the intestinal microflora and duodenal villus surface area. This research expands the understanding of the prebiotics' properties of chickpea and lentil extracts, and peptides' effects on calcium metabolism and gut health.

  7. 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.

  8. 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

  9. Extracellular life cycle of ComS, the competence-stimulating peptide of Streptococcus thermophilus.

    PubMed

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

    2013-04-01

    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.

  10. 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.

  11. 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

  12. Oleic acid stimulates glucagon-like peptide-1 release from enteroendocrine cells by modulating cell respiration and glycolysis.

    PubMed

    Clara, Rosmarie; Langhans, Wolfgang; Mansouri, Abdelhak

    2016-03-01

    Glucagon-like peptide-1 (GLP-1) is a potent satiating and incretin hormone released by enteroendocrine L-cells in response to eating. Dietary fat, in particular monounsaturated fatty acids, such as oleic acid (OA), potently stimulates GLP-1 secretion from L-cells. It is, however, unclear whether the intracellular metabolic handling of OA is involved in this effect. First we determined the optimal medium for the bioenergetics measurements. Then we examined the effect of OA on the metabolism of the immortalized enteroendocrine GLUTag cell model and assessed GLP-1 release in parallel. We measured oxygen consumption rate and extracellular acidification rate in response to OA and to different metabolic inhibitors with the Seahorse extracellular flux analyzer. OA increased cellular respiration and potently stimulated GLP-1 release. The fatty acid oxidation inhibitor etomoxir did neither reduce OA-induced respiration nor affect the OA-induced GLP-1 release. In contrast, inhibition of the respiratory chain or of downstream steps of aerobic glycolysis reduced the OA-induced GLP-1 release, and an inhibition of the first step of glycolysis by addition of 2-deoxy-d-glucose even abolished it. These findings indicate that an indirect stimulation of glycolysis is crucial for the OA-induced release of GLP-1. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Peptide cotransporter 1 in intestine and organic anion transporters in kidney are targets of interaction between JBP485 and lisinopril in rats.

    PubMed

    Guo, Xinjin; Meng, Qiang; Liu, Qi; Wang, Changyuan; Mao, Qi; Sun, Huijun; Peng, Jinyong; Kaku, Taiichi; Liu, Kexin

    2012-01-01

    The purpose of this study was to clarify the pharmacokinetic mechanism of interaction between JBP485 (cyclo-trans-4-L-hydroxyprolyl-L-serine, a dipeptide with antihepatitis activity) and lisinopril (an angiotensin-converting enzyme inhibitor) in vitro and in vivo. When JBP485 and lisinopril were administered orally simultaneously, the plasma concentrations of the two drugs were decreased significantly, but few changes were observed after simultaneous intravenous administration of the two drugs. The uptake of JBP485 and lisinopril in everted intestinal sacs and in HeLa cells transfected with human peptide cotransporter 1 (PEPT1), as well as absorption of JBP485 and lisinopril after jejunal perfusion were reduced after simultaneous drug administration, which suggested that the first target of drug interaction was PEPT1 in the intestine during the absorption process. The cumulative urinary excretions and renal clearance of the two drugs were decreased after intravenous co-administration, while uptakes of the two drugs in kidney slices and hOAT1/hOAT3-transfected HEK293 cells were decreased. These results indicated that the second target of drug-drug interaction was located in the kidney. These findings confirmed that the pharmacokinetic mechanism of interaction between JBP485 and lisinopril could be explained by their inhibition of the same transporters in the intestinal mucosa (PEPT1) and kidneys (OATs).

  14. 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.

  15. 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.

  16. Glucagon-like peptide 2 function in domestic animals.

    PubMed

    Burrin, D G; Stoll, B; Guan, X

    2003-03-01

    Glucagon-like peptide 2 (GLP-2) is a member of family of peptides derived from the proglucagon gene expressed in the intestines, pancreas and brain. Tissue-specific posttranslational processing of proglucagon leads to GLP-2 and GLP-1 secretion from the intestine and glucagon secretion from the pancreas. GLP-2 and GLP-1 are co-secreted from the enteroendocrine L-cells located in distal intestine in response to enteral nutrient ingestion, especially carbohydrate and fat. GLP-2 secretion is mediated by direct nutrient stimulation of the L-cells and indirect action from enteroendocrine and neural inputs, including GIP, gastrin-releasing peptide (GRP) and the vagus nerve. GLP-2 is secreted as a 33-amino acid peptide and is rapidly cleaved by dipeptidylpeptidase IV (DPP-IV) to a truncated peptide which acts as a weak agonist with competitive antagonistic properties. GLP-2 acts to enhance nutrient absorption by inhibiting gastric motility and secretion and stimulating nutrient transport. GLP-2 also suppresses food intake when infused centrally. The trophic actions of GLP-2 are specific for the intestine and occur via stimulation of crypt cell proliferation and suppression of apoptosis in mucosal epithelial cells. GLP-2 reduces gut permeability, bacterial translocation and proinflammatory cytokine expression under conditions of intestinal inflammation and injury. The effects of GLP-2 are mediated by a G-protein-linked receptor that is localized to the intestinal mucosa and hypothalamus. The intestinal localization of the GLP-2R to neural and endocrine cells, but not enterocytes, suggests that its actions are mediated indirectly via a secondary signaling mechanism. The implications of GLP-2 in domestic animal production are largely unexplored. However, GLP-2 may have therapeutic application in treatment of gastrointestinal injury and diarrheal diseases that occur in developing neonatal and weanling animals.

  17. 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

  18. Tickling the TCR: selective T-cell functions stimulated by altered peptide ligands.

    PubMed

    Evavold, B D; Sloan-Lancaster, J; Allen, P M

    1993-12-01

    Recent observations of T-cell responses following T-cell receptor (TCR) interaction with altered peptide ligands have highlighted the complexity of this signalling system. The indications are that the TCR responds to minor changes in ligand with gradations of T-cell activation and effector functions. Brian Evavold, Joanne Sloan-Lancaster and Paul Allen review these studies and present a model in which partial T-cell activation and TCR antagonism are related events in a continuum of signalling through the TCR.

  19. 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. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. 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.

  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. Alpha-melanocyte-stimulating hormone peptide analogs labeled with technetium-99m and indium-111 for malignant melanoma targeting.

    PubMed

    Chen, JianQing; Cheng, Zhen; Miao, Yubin; Jurisson, Silvia S; Quinn, Thomas P

    2002-02-15

    Previous studies have shown that the compact structure of a rhenium-cyclized alpha--melanocyte-stimulating hormone peptide analog, [Cys3410,D-Phe7]alpha-MSH(3--13), or Re-CCMSH, significantly enhanced its in vivo tumor uptake and retention. In this study, the metal chelate 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was coupled to the N-terminus of Re-CCMSH in order to develop a melanoma-targeting peptide that could be labeled with a wider variety of imaging and therapeutic radionuclides. Biodistribution properties of indium-111 ((111)In)--labeled DOTA-Re-CCMSH were compared with the non-DOTA-containing technetium-99m ((99m)Tc)--CCMSH in murine melanoma--bearing C57 mice to determine the effects of DOTA on tumor uptake and whole-body clearance. The tumor targeting capacity and clearance kinetics of (111)In-DOTA-Re-CCMSH were also compared with other related cyclic and linear (111)In-labeled DOTA-alpha-MSH complexes. The in vivo distribution data showed that the conjugation of DOTA to Re-CCMSH did not reduce its initial tumor uptake kinetics but did enhance its tumor retention and renal clearance properties. The tumor uptake of (111)In-DOTA-Re-CCMSH was significantly higher than the other (111)In-DOTA--coupled cyclic or linear alpha-MSH analogs used in this study. Moreover, (111)In-DOTA-Re-CCMSH displayed lower radioactivity accumulation in normal tissues of interest than its non-Re-cyclized counterpart, (111)In-DOTA-CCMSH; the disulfide bond--cyclized (111)In-DOTA-CMSH; or the linear (111)In-DOTA-NDP. Peptide cyclization via rhenium coordination significantly enhanced the tumor targeting and renal clearance properties of DOTA-Re-CCMSH, making it an excellent candidate for melanoma radiodetection and radiotherapy. Copyright 2002 American Cancer Society.

  3. 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

  4. Cyclooxygenase-2 stimulates production of amyloid beta-peptide in neuroblastoma x glioma hybrid NG108-15 cells.

    PubMed

    Kadoyama, K; Takahashi, Y; Higashida, H; Tanabe, T; Yoshimoto, T

    2001-02-23

    Cyclooxygenase (COX) synthesizes bioactive prostaglandins from arachidonic acid, and there are COX-1 and COX-2 isoforms with distinct pathophysiological functions. Recent studies demonstrated that COX-2 expression was up-regulated in the brain of patients with Alzheimer's disease. We established mouse neuroblastoma x rat glioma hybrid NG108-15 cells stably expressing human COX-2. The COX-2-expressing cells showed 3- to 4-fold increases in both COX activity and prostaglandin E(2) production. The mRNA level of amyloid precursor protein (APP) was elevated by approximately 2-fold in the COX-2-expressing cells compared with mock-transfected cells. Amyloid beta-peptide and a secreted form of APP, both derived from APP by proteolysis was also increased. Interestingly, neurite outgrowth was stimulated in the COX-2-expressing cells with concomitant reduction of the cell proliferation rate. A selective COX-2 inhibitor (JTE-522) and a nonselective COX inhibitor (indomethacin) suppressed production of amyloid beta-peptide and a secreted form of APP by inhibition of APP mRNA level, suggesting that COX-2 plays important roles in the neurodegenerative processes of Alzheimer's disease.

  5. 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.

  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. 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

  8. Frog skin peptides (tigerinin-1R, magainin-AM1, -AM2, CPF-AM1, and PGla-AM1) stimulate secretion of glucagon-like peptide 1 (GLP-1) by GLUTag cells.

    PubMed

    Ojo, O O; Conlon, J M; Flatt, P R; Abdel-Wahab, Y H A

    2013-02-01

    Skin secretions of several frog species contain host-defense peptides with multiple biological activities including in vitro and in vivo insulin-releasing actions. This study investigates the effects of tigerinin-1R from Hoplobatrachus rugulosus (Dicroglossidae) and magainin-AM1, magainin-AM2, caerulein precursor fragment (CPF-AM1) and peptide glycine leucine amide (PGLa-AM1) from Xenopus amieti (Pipidae) on GLP-1 secretion from GLUTag cells. Tigerinin-1R showed the highest potency producing a significant (P<0.05) increase in GLP-1 release at a concentration of 0.1nM for the cyclic peptide and 0.3nM for the reduced form. All peptides from X. amieti significantly (P<0.05) stimulated GLP-1 release at concentrations ⩾300nM with magainin-AM2 exhibiting the greatest potency (minimum concentration producing a significant stimulation=1nM). The maximum stimulatory response (3.2-fold of basal rate, P<0.001) was produced by CPF-AM1 at a concentration of 3μM. No peptide stimulated release of the cytosolic enzyme, lactate dehydrogenase from GLUTag cells at concentrations up to 3μM indicating that the integrity of the plasma membrane had been preserved. The data indicate that frog skin peptides, by stimulating GLP-1 release as well as direct effects on insulin secretion, show therapeutic potential as agents for the treatment of type 2 diabetes. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  9. Gastric bypass surgery restores meal stimulation of the anorexigenic gut hormones glucagon-like peptide-1 and peptide YY independently of caloric restriction.

    PubMed

    Evans, Sarah; Pamuklar, Zehra; Rosko, Jonathan; Mahaney, Patrick; Jiang, Ning; Park, Chan; Torquati, Alfonso

    2012-04-01

    The effects of gastric bypass surgery on the secretion of the anorexigenic gut-derived hormones glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), independent of caloric restriction and due to different dietary macronutrients, is not well characterized. This study examines the effects of a mixed-nutrient or high-fat liquid meal on the postprandial stimulation of GLP-1 and PYY following gastric bypass or equivalent hypocaloric diet. Total PYY and active GLP-1 were measured fasting and at multiple points after standardized mixed-nutrient and high-fat liquid meals in two matched groups of obese subjects. The meal stimulation tests were performed before and 14.6 ± 3.3 days after gastric bypass (GBP, n = 10) and before and after a 7-day hypocaloric liquid diet matching the post-GBP diet (control, n = 10). Mixed-nutrient and high-fat postprandial GLP-1 levels increased following GBP (mixed-nutrient peak: 85.0 ± 28.6-323 ± 51 pg/ml, P < 0.01; high-fat peak: 81.8 ± 9.6-278 ± 49 pg/ml, P < 0.01), but not after diet (mixed-nutrient peak: 104.4 ± 9.4-114.9 ± 15.8 pg/ml, P = NS; high-fat peak: 118.1 ± 16.4-104.4 ± 10.8 pg/ml, P = NS). The postprandial PYY response also increased after GBP but not diet, though the increase in peak PYY did not reach statistical significance (GBP mixed-nutrient peak: 134.8 ± 26.0-220.7 ± 52.9 pg/ml, P = 0.09; GBP high-fat peak: 142.1 ± 34.6-197.9 ± 12.7 pg/ml, P = 0.07; diet mixed-nutrient peak: 99.8 ± 8.0-101.1 ± 13.3 pg/ml, P = NS; diet high-fat peak: 105.0 ± 8.8-103.1 ± 11.8 pg/ml, P = NS). The postprandial GLP-1 response was not affected by the macronutrient content of the meal. However, following GBP the mixed-nutrient PYY total area under the curve (AUC(0-120)) was significantly greater than the high-fat PYY AUC(0-120) (22,081 ± 5,662 pg/ml min vs. 18,711 ± 1,811 pg/ml min, P = 0.04). Following GBP there is an increase in the postprandial stimulation of PYY and GLP-1 that is independent of caloric restriction. The

  10. GASTRIC BYPASS SURGERY RESTORES MEAL STIMULATION OF THE ANOREXIGENIC GUT HORMONES GLUCAGON-LIKE PEPTIDE-1 AND PEPTIDE YY INDEPENDENTLY OF CALORIC RESTRICTION

    PubMed Central

    Evans, Sarah; Pamuklar, Zehra; Rosko, Jonathan; Mahaney, Patrick; Jiang, Ning; Park, Chan; Torquati, Alfonso

    2011-01-01

    Background The effects of gastric bypass surgery on the secretion of the anorexogenic gut-derived hormones glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), independent of caloric restriction and due to different dietary macronutrients, is not well-characterized. This study examines the effects of a mixed-nutrient or high-fat liquid meal on the postprandial stimulation of GLP-1 and PYY following gastric bypass or equivalent hypocaloric diet. Methods Total PYY and active GLP-1 were measured fasting and at multiple points after standardized mixed-nutrient and high-fat liquid meals in two matched groups of obese subjects. The meal stimulation tests were performed before and 14.6±3.3 days after gastric bypass (GBP, n=10) and before and after a 7-day hypocaloric liquid diet matching the post-GBP diet (Control, n=10). Results Mixed-nutrient and high-fat postprandial GLP-1 levels increased following GBP (mixed-nutrient peak: 85.0±28.6 pg/ml to 323±51 pg/ml, p<0.01; high-fat peak: 81.8±9.6 pg/ml to 278±49 pg/ml, p<0.01), but not after diet (mixed-nutrient peak: 104.4±9.4 pg/ml to 114.9±15.8 pg/ml, p=NS; high-fat peak: 118.1±16.4 pg/ml to 104.4±10.8 pg/ml, p=NS). The postprandial PYY response also increased after GBP but not diet, though the increase in peak PYY did not reach statistical significance (GBP mixed-nutrient peak: 134.8±26.0 pg/ml to 220.7±52.9 pg/ml, p=0.09; GBP high-fat peak: 142.1±34.6 pg/ml to 197.9±12.7 pg/ml, p=0.07; diet mixed-nutrient peak: 99.8±8.0 pg/ml to 101.1±13.3 pg/ml, p=NS; diet high-fat peak: 105.0±8.8 pg/ml to 103.1±11.8 pg/ml, p=NS). The postprandial GLP-1 response was not affected by the macronutrient content of the meal. However, following GBP the mixed-nutrient PYY AUC0–120 was significantly greater than the high-fat PYY AUC0–120 (22081±5662 pg/ml•min versus 18711±1811 pg/ml•min, p=0.04). Conclusions Following GBP there is an increase in the postprandial stimulation of PYY and GLP-1 that is independent from

  11. Intra-Amniotic Administration (Gallus gallus) of Cicer arietinum and Lens culinaris Prebiotics Extracts and Duck Egg White Peptides Affects Calcium Status and Intestinal Functionality

    PubMed Central

    Hou, Tao; Glahn, Raymond P.; Tako, Elad

    2017-01-01

    Calcium (Ca) is one of the most abundant inorganic elements in the human body and has many important physiological roles. Prebiotics and bioactive peptides are two important substances used to promote calcium uptake. However, the difference in mechanisms of the calcium uptake from these two supplements is not clear. By using the Gallus gallus model and the intra-amniotic administration procedure, the aim of this study was to investigate whether Ca status, intestinal functionality, and health-promoting bacterial populations were affected by prebiotics extracted from chickpea and lentil, and duck egg white peptides (DPs). Eleven groups (non-injected; 18 MΩ H2O; 4 mmol/L CaCl2; 50 mg/mL chickpea + 4 mmol/L CaCl2; 50 mg/mL lentil + 4 mmol/L CaCl2; 40 mg/mL DPs + 4 mmol/L CaCl2; 5 mg/mL Val-Ser-Glu-Glu (VSEE) + 4 mmol/L CaCl2; 50 mg/mL chickpea; 50 mg/mL lentil; 40 mg/mL DPs; 5 mg/mL VSEE) were utilized. Upon hatch, blood, cecum, small intestine, liver and bone were collected for assessment of serum bone alkaline phosphate level (BALP), the relative abundance of intestinal microflora, expression of Ca-related genes, brush border membrane (BBM) functional genes, and liver and bone mineral levels, respectively. The BALP level increased in the presence of lentil, DPs and VSEE (p < 0.05). The relative abundance of probiotics increased significantly (p < 0.05) by VSEE + Ca and chickpea. The expression of CalbindinD9k (Ca transporter) increased (p < 0.05) in Ca, chickpea + Ca and lentil + Ca groups. In addition, the brush border membrane functionality genes expressions increased (p < 0.05) by the chickpea or lentil extracts. Prebiotics and DPs beneficially affected the intestinal microflora and duodenal villus surface area. This research expands the understanding of the prebiotics’ properties of chickpea and lentil extracts, and peptides’ effects on calcium metabolism and gut health. PMID:28754012

  12. Glucagon-like peptide 2 prevents down-regulation of intestinal multidrug resistance-associated protein 2 and P-glycoprotein in endotoxemic rats.

    PubMed

    Arana, Maite Rocío; Tocchetti, Guillermo Nicolás; Zecchinati, Felipe; Londero, Ana Sofía; Dominguez, Camila; Perdomo, Virginia; Rigalli, Juan Pablo; Villanueva, Silvina Stella Maris; Mottino, Aldo Domingo

    2017-08-23

    Multidrug resistance-associated protein 2 (Mrp2, ABCC2) and P-glycoprotein (P-gp, ABCB1) constitute essential components of the intestinal biochemical barrier that prevent incorporation of food contaminants, drugs or toxic metabolites into the blood stream. Endotoxemia induced in rats by administration of bacterial lipopolysaccharide (LPS) results in elevated intestinal permeability and toxicity of xenobiotics in part associated with down-regulation of expression and activity of Mrp2 and P-gp. We evaluated the protective effect of glucagon-like peptide 2 (GLP-2), a peptide hormone with enterotrophic properties, on Mrp2 and P-gp alterations induced by single i.p. injection of LPS (5mg/kg b.wt.) to rats. Two different protocols of GLP-2 administration, namely prevention and reversion, were examined. The prevention protocol consisted of 7s.c. injections of GLP-2 (125μg/kg b.wt.) administered every 12h, starting 60h before LPS administration. The reversion protocol consisted of 2 doses of GLP-2, starting 3h after LPS injection. Intestinal samples were collected 24h after LPS administration and expression (protein and mRNA) and activity of Mrp2 were evaluated in proximal jejunum whereas those of P-gp were studied in ileum. GLP-2 completely neutralized down-regulation of expression of Mrp2 and P-gp and loss of their respective activities induced by LPS under prevention protocol. GLP-2 was also able to prevent internalization of both transporters from the apical membrane of the enterocyte to intracellular compartments, as detected by confocal microscopy. LPS induced an increase in IL-1β and oxidized glutathione tissue levels, which were also counterbalanced by GLP-2 administration. In contrast, the reversion protocol failed to attenuate Mrp2 and P-gp down-regulation induced by LPS. We conclude that GLP-2 can prevent down-regulation of intestinal expression and activity of Mrp2 and P-gp in endotoxemic rats and that IL-1β and oxidative stress constitute potential targets

  13. 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.

  14. Human host defense peptide LL-37 stimulates virulence factor production and adaptive resistance in Pseudomonas aeruginosa.

    PubMed

    Strempel, Nikola; Neidig, Anke; Nusser, Michael; Geffers, Robert; Vieillard, Julien; Lesouhaitier, Olivier; Brenner-Weiss, Gerald; Overhage, Joerg

    2013-01-01

    A multitude of different virulence factors as well as the ability to rapidly adapt to adverse environmental conditions are important features for the high pathogenicity of Pseudomonas aeruginosa. Both virulence and adaptive resistance are tightly controlled by a complex regulatory network and respond to external stimuli, such as host signals or antibiotic stress, in a highly specific manner. Here, we demonstrate that physiological concentrations of the human host defense peptide LL-37 promote virulence factor production as well as an adaptive resistance against fluoroquinolone and aminoglycoside antibiotics in P. aeruginosa PAO1. Microarray analyses of P. aeruginosa cells exposed to LL-37 revealed an upregulation of gene clusters involved in the production of quorum sensing molecules and secreted virulence factors (PQS, phenazine, hydrogen cyanide (HCN), elastase and rhamnolipids) and in lipopolysaccharide (LPS) modification as well as an induction of genes encoding multidrug efflux pumps MexCD-OprJ and MexGHI-OpmD. Accordingly, we detected significantly elevated levels of toxic metabolites and proteases in bacterial supernatants after LL-37 treatment. Pre-incubation of bacteria with LL-37 for 2 h led to a decreased susceptibility towards gentamicin and ciprofloxacin. Quantitative Realtime PCR results using a PAO1-pqsE mutant strain present evidence that the quinolone response protein and virulence regulator PqsE may be implicated in the regulation of the observed phenotype in response to LL-37. Further experiments with synthetic cationic antimicrobial peptides IDR-1018, 1037 and HHC-36 showed no induction of pqsE expression, suggesting a new role of PqsE as highly specific host stress sensor.

  15. Human Host Defense Peptide LL-37 Stimulates Virulence Factor Production and Adaptive Resistance in Pseudomonas aeruginosa

    PubMed Central

    Strempel, Nikola; Neidig, Anke; Nusser, Michael; Geffers, Robert; Vieillard, Julien; Lesouhaitier, Olivier; Brenner-Weiss, Gerald; Overhage, Joerg

    2013-01-01

    A multitude of different virulence factors as well as the ability to rapidly adapt to adverse environmental conditions are important features for the high pathogenicity of Pseudomonas aeruginosa. Both virulence and adaptive resistance are tightly controlled by a complex regulatory network and respond to external stimuli, such as host signals or antibiotic stress, in a highly specific manner. Here, we demonstrate that physiological concentrations of the human host defense peptide LL-37 promote virulence factor production as well as an adaptive resistance against fluoroquinolone and aminoglycoside antibiotics in P. aeruginosa PAO1. Microarray analyses of P. aeruginosa cells exposed to LL-37 revealed an upregulation of gene clusters involved in the production of quorum sensing molecules and secreted virulence factors (PQS, phenazine, hydrogen cyanide (HCN), elastase and rhamnolipids) and in lipopolysaccharide (LPS) modification as well as an induction of genes encoding multidrug efflux pumps MexCD-OprJ and MexGHI-OpmD. Accordingly, we detected significantly elevated levels of toxic metabolites and proteases in bacterial supernatants after LL-37 treatment. Pre-incubation of bacteria with LL-37 for 2 h led to a decreased susceptibility towards gentamicin and ciprofloxacin. Quantitative Realtime PCR results using a PAO1-pqsE mutant strain present evidence that the quinolone response protein and virulence regulator PqsE may be implicated in the regulation of the observed phenotype in response to LL-37. Further experiments with synthetic cationic antimicrobial peptides IDR-1018, 1037 and HHC-36 showed no induction of pqsE expression, suggesting a new role of PqsE as highly specific host stress sensor. PMID:24349231

  16. 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.

  17. 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

    USDA-ARS?s Scientific Manuscript database

    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...

  18. Daily variations in concentration of vasoactive intestinal peptide immunoreactivity in hypothalamic nuclei of rats rendered diurnal by restricted-schedule feeding.

    PubMed

    Morin, A J; Denoroy, L; Jouvet, M

    1993-04-02

    We previously described that in the suprachiasmatic (SCN), peri-(PeVN) and paraventricular (PaVN) nuclei of normal rats, vasoactive intestinal peptide (VIP)-like immunoreactivity (VIP-LI) accumulates during the night period and decreases during the day. In order to determine whether these variations are linked to the light-dark cycle or are a consequence of sleep-wake rhythm expression, we dissociated these two parameters by restricting feeding to diurnal hours. In these conditions which inverse the paradoxical sleep rhythm, the VIP-LI pattern is perturbed and its minimum advanced by 4 h in the SCN. In the PeVN, the daily pattern is maintained but the minimum is also advanced by 4 h. Finally, the rhythm is abolished in the PaVN. These circadian fluctuations indicate that the hypothalamic VIP-LI rhythm is not linked to the paradoxical sleep rhythm but could be sensitive to photic and non-photic Zeitgeber.

  19. 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

  20. 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.

  1. 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

  2. Dietary protein composition influences abundance of peptide and amino acid transporter messenger ribonucleic acid in the small intestine of 2 lines of broiler chicks.

    PubMed

    Gilbert, E R; Li, H; Emmerson, D A; Webb, K E; Wong, E A

    2010-08-01

    This study evaluated the effect of dietary protein composition on mRNA abundance of a peptide transporter (peptide transporter 1, PepT1), amino acid (AA) transporters [Na(+)-independent cationic and zwitterionic AA transporter (b(o,+)AT), excitatory AA transporter 3 (EAAT3), Na(+)-independent cationic and Na(+)-dependent neutral AA transporter 2 (y(+)LAT2), L-type AA transporter 1 (LAT1), and cationic AA transporter 1 (CAT1)], and a digestive enzyme (aminopeptidase N) in 2 lines (A and B) of broilers that differentially express PepT1 mRNA (line B > line A). From d 8 to 15 posthatch, birds were fed 1 of 3 diets. Protein sources included whey protein concentrate, a whey partial hydrolysate (WPH), or a mixture of free AA (AA) identical to the composition of whey. Quantities of mRNA were assayed by real-time PCR in the small intestine of males at d 8, 9, 11, 13, and 15. For all genes except LAT1, abundance of mRNA was greatest in line B birds that consumed the WPH diet (P < 0.006). When mRNA abundance was normalized to beta-actin quantities, this effect disappeared, demonstrating a generalized effect on gene expression in line B birds that consumed the hydrolysate. There was a greater villus height:crypt depth ratio (P < 0.05) in line B birds fed the WPH diet as compared with line A. In conclusion, line B birds, which express greater PepT1, displayed enhanced intestinal mucosal absorptive surface area and differential regulation of PepT1, AA transporters, and aminopeptidase N in response to dietary protein composition.

  3. 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.

  4. 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.

  5. 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.

  6. Expression of trefoil peptides (TFF1, TFF2, and TFF3) in gastric carcinomas, intestinal metaplasia, and non-neoplastic gastric tissues.

    PubMed

    Leung, Wai K; Yu, Jun; Chan, Francis K L; To, Ka F; Chan, Michael W Y; Ebert, M P A; Ng, Enders K W; Chung, S C Sydney; Malfertheiner, Peter; Sung, Joseph J Y

    2002-08-01

    Trefoil factor family (TFF) domain peptides consist of three members that play a role in intestinal mucosal defence and repair, and in tumourigenesis. The role of the three TFF members in the gastric carcinogenesis cascade remains poorly defined. This study examined seven gastric cell lines, 50 gastric cancers and their adjacent non-cancer tissues, and tissues from 40 non-cancer patients, in order to elucidate the chronology of TFF expression in various stages of gastric carcinogenesis. TFF expression was determined by RT-PCR, immunohistochemistry, and western blot. Aberrant expression of TFF1, TFF2, and TFF3 was frequently detected in gastric cell lines. Specifically, TFF1 was detected in all non-cancer patients, but was detected in only 50% of gastric cancer and 66% of adjacent normal tissues. TFF2 expression was demonstrated in 87.5% of non-cancer patients, 34% of gastric carcinomas, and 58% of adjacent non-cancer tissues. There was a significant correlation between TFF1 and TFF2 expression in gastric cancer and adjacent non-cancer tissues (p<0.001). By contrast, TFF3 was detected in 25% of non-cancer patients and showed a predilection for areas with intestinal metaplasia (p=0.005). Sixty-two per cent of gastric cancers and 24% of neighbouring non-cancer tissues showed TFF3 expression. Immunoreactivity against TFF3 was demonstrated in goblet cells of intestinal metaplasia and within the cytoplasm and nuclei of tumour cells. Progressive loss of TFF1 and TFF2, together with the induction of TFF3, is likely to be involved in the early stage of the multi-step gastric carcinogenesis pathway. Copyright 2002 John Wiley & Sons, Ltd.

  7. 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

  8. Stimulation of human formyl peptide receptors by calpain inhibitors: homology modeling of receptors and ligand docking simulation.

    PubMed

    Fujita, Hisakazu; Kato, Takayuki; Watanabe, Norifumi; Takahashi, Tatsuji; Kitagawa, Seiichi

    2011-12-15

    Calpain inhibitors, including peptide aldehydes (N-acetyl-Leu-Leu-Nle-CHO and N-acetyl-Leu-Leu-Met-CHO) and α-mercapto-acrylic acid derivatives (PD150606 and PD151746), have been shown to stimulate phagocyte functions via activation of human formyl peptide receptor (hFPR) and/or hFPR-like 1 (hFPRL1). Using the homology modeling of the receptors and the ligand docking simulation, here we show that these calpain inhibitors could bind to the putative N-formyl-Met-Leu-Phe (fMLF) binding site on hFPR and/or hFPRL1. The studies with HEK-293 cells stably expressing hFPR or hFPRL1 showed that the concentrations of calpain inhibitors required to induce an increase in cytoplasmic free Ca(2+) ([Ca(2+)](i)) was much higher (>100 folds) than those of fMLF and Trp-Lys-Tyr-Met-Val-D-Met (WKYMVm). HEK-293 cells expressing hFPR or hFPRL1 with the mutated fMLF binding site never exhibited the [Ca(2+)](i) response to calpain inhibitors. When the optimal concentrations of each stimulus were used, pretreatment of cells with fMLF or WKYMVm abolished an increase in [Ca(2+)](i) induced by calpain inhibitors as well as the same stimulus, whereas pretreatment of cells with calpain inhibitors significantly suppressed, but never abolished, the [Ca(2+)](i) response induced by fMLF or WKYMVm, suggesting that the binding affinity of the inhibitors to the putative fMLF binding site may be lower than that of fMLF or WKYMVm. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. 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.

  10. 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

  11. Bioactive peptides encrypted in milk proteins: proteolytic activation and thropho-functional properties.

    PubMed

    Meisel, H; Bockelmann, W

    1999-01-01

    The bioactivities of peptides encrypted in major milk proteins are latent until released and activated by enzymatic proteolysis, e.g. during gastrointestinal digestion or food processing. The proteolytic system of lactic acid bacteria can contribute to the liberation of bioactive peptides. In vitro, the purified cell wall proteinase of Lactococcus lactis was shown to liberate oligopeptides from beta- and alpha-caseins which contain amino acid sequences present in casomorphins, casokinines, and immunopeptides. The further degradation of these peptides by endopeptidases and exopeptidases of lactic acid bacteria could lead to the liberation of bioactive peptides in fermented milk products. However, the sequences of practically all known biologically active peptides can also be cleaved by peptidases from lactic acid bacteria. Activated peptides are potential modulators of various regulatory processes in the body: Opioid peptides are opioid receptor ligands which can modulate absorption processes in the intestinal tract, angiotensin-I-converting enzyme (ACE)-inhibitory peptides are hemodynamic regulators and exert an antihypertensive effect, immunomodulating casein peptides stimulate the activities of cells of the immune system, antimicrobial peptides kill sensitive microorganisms, antithrombotic peptides inhibit aggregation of platelets and caseinophosphopeptides may function as carriers for different minerals, especially calcium. Bioactive peptides can interact with target sites at the luminal side of the intestinal tract. Furthermore, they can be absorbed and then reach peripheral organs. Food-derived bioactive peptides are claimed to be health enhancing components which can be used for functional food and pharmaceutical preparations.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  13. 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.

  14. 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

  15. 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.

  16. 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

  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. 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

  19. 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.

  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.