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Sanchez V, Rosales-Mendoza S, Monreal-Escalante E, Murillo-Álvarez JI, Angulo C. Conjugation of β-glucans on heat-stable enterotoxin (ST) to enhance the immunogenic response in mouse leucocytes. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 118:111464. [PMID: 33255046 DOI: 10.1016/j.msec.2020.111464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/22/2020] [Accepted: 08/26/2020] [Indexed: 11/19/2022]
Abstract
Enterotoxigenic Escherichia coli (ETEC) is an important diarrhea-causing pathogen for humans. Heat-stable enterotoxin (ST) plays a crucial role in triggering diarrhea and ETEC pathogenesis. However, ST is a small peptide that lacks immunogenic activity itself but becomes immunogenic when it is coupled to a carrier molecule. In this study, the β-glucans (BG) from yeasts have been used to test their immunomodulatory activity and adjuvant effect on the properties of ST. This study aimed to synthesize and characterize a conjugate of yeast-derived β-glucan with the ST enterotoxin (BG-ST) and evaluate the antigenic and antioxidant activities in mouse splenocytes. Fourier transform infrared spectroscopy and scanning electron microscopy analysis showed new bands and changes in morphology, respectively, confirming ST was successfully coupled to beta glucan. Additionally, according to the enzyme-linked immunosorbent assay (ELISA), conjugation efficiency was almost 90%. Cellular viability, phagocytic cell proportion, and respiratory burst enhanced splenocytes stimulated by BG-ST. In addition, nitric oxide production and antioxidant enzymes increased in cells stimulated with BG-ST, BG and ST. In conclusion, the results revealed the successful conjugation of β-glucan with ST peptide enhancing immune and antioxidant parameters to a greater extent than their individual components.
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Affiliation(s)
- Veronica Sanchez
- Immunology & Vaccinology Group, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Av. Instituto Politécnico Nacional 195, Playa Palo de Santa Rita, La Paz, B.C.S. 23096, Mexico; Sección de Biotecnología, Centro de Investigación en Ciencias de la Salud y Biomedicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Av. Sierra Leona 550, Lomas 2ª, Sección, 78210 San Luis Potosí, Mexico
| | - Sergio Rosales-Mendoza
- Sección de Biotecnología, Centro de Investigación en Ciencias de la Salud y Biomedicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Av. Sierra Leona 550, Lomas 2ª, Sección, 78210 San Luis Potosí, Mexico
| | - Elizabeth Monreal-Escalante
- Immunology & Vaccinology Group, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Av. Instituto Politécnico Nacional 195, Playa Palo de Santa Rita, La Paz, B.C.S. 23096, Mexico; CONACYT-Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, La Paz, B.C.S 23090, Mexico
| | - Jesús I Murillo-Álvarez
- Centro Interdisciplinario de Ciencias Marinas-IPN (CICIMAR), Avenida IPN s/n, 23096 La Paz, B.C.S., Mexico
| | - Carlos Angulo
- Immunology & Vaccinology Group, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Av. Instituto Politécnico Nacional 195, Playa Palo de Santa Rita, La Paz, B.C.S. 23096, Mexico.
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Belik J, Shifrin Y, Arning E, Bottiglieri T, Pan J, Daigneault MC, Allen-Vercoe E. Intestinal microbiota as a tetrahydrobiopterin exogenous source in hph-1 mice. Sci Rep 2017; 7:39854. [PMID: 28079055 PMCID: PMC5227711 DOI: 10.1038/srep39854] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 11/29/2016] [Indexed: 01/07/2023] Open
Abstract
Tetrahydrobiopterin (BH4) is a cofactor of a number of regulatory enzymes. Although there are no known BH4 exogenous sources, the tissue content of this biopterin increases with age in GTP cyclohydrolase 1-deficient hyperphenylalaninemia-1 (hph-1) mice. Since certain bacteria are known to generate BH4, we hypothesize that generation of this biopterin by the intestinal microbiota contributes to its tissue increase in hph-1 adult mice. The goal of this study was to comparatively evaluate hph-1 mice and wild-type C57Bl/6 controls for the presence of intestinal BH4-producing bacteria. Newborn and adult mice fecal material was screened for 6-pyruvoyltetrahydropterin synthase (PTPS-2) an enzyme only present in BH4-generating bacteria. Adult, but not newborn, wild-type control and hph-1 mouse fecal material contained PTPS-2 mRNA indicative of the presence of BH4-generating bacteria. Utilizing chemostat-cultured human fecal bacteria, we identified the PTPS-2-producing bacteria as belonging to the Actinobacteria phylum. We further confirmed that at least two PTPS-2-producing species, Aldercreutzia equolifaciens and Microbacterium schleiferi, generate BH4 and are present in hph-1 fecal material. In conclusion, intestinal Actinobacteria generate BH4. This finding has important translational significance, since manipulation of the intestinal flora in individuals with congenital biopterin deficiency may allow for an increase in total body BH4 content.
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Affiliation(s)
- Jaques Belik
- Physiology & Experimental Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Ontario M5G 1X8, Canada
- Department of Paediatrics and Physiology, University of Toronto, Toronto, Ontario, M5G 1X8 Canada
| | - Yulia Shifrin
- Physiology & Experimental Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Ontario M5G 1X8, Canada
| | - Erland Arning
- Baylor Research Institute, Institute of Metabolic Disease, Dallas, TX, 75226, USA
| | - Teodoro Bottiglieri
- Baylor Research Institute, Institute of Metabolic Disease, Dallas, TX, 75226, USA
| | - Jingyi Pan
- Physiology & Experimental Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Ontario M5G 1X8, Canada
| | | | - Emma Allen-Vercoe
- Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1 Canada
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Welsh C, Enomoto M, Pan J, Shifrin Y, Belik J. Tetrahydrobiopterin deficiency induces gastroparesis in newborn mice. Am J Physiol Gastrointest Liver Physiol 2013; 305:G47-57. [PMID: 23639814 DOI: 10.1152/ajpgi.00424.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Pyloric stenosis, the most common infant gastrointestinal disease, has no known etiology and clinically presents as abnormal gastric emptying with evidence of pyloric muscle hypertrophy. Whether abnormalities in gastric muscle contraction and/or relaxation have a role in this condition is poorly known, but gastroparesis is commonly observed in association with delayed gastric emptying in adults. Therefore, we evaluated the tetrahydrobiopterin (BH4)-deficient newborn mouse model of this disease (hph-1) and hypothesized that their gastric muscle properties are impaired, when compared with wild-type control animals. In vitro studies evaluating the age-dependent gastric fundus muscle contraction and relaxation potential were conducted. Compared with wild-type mice, the hph-1 stomach content/body weight ratio was significantly increased in newborn but not juvenile or adult animals, confirming abnormal gastric emptying. Gastric tissue neuronal nitric oxide synthase (nNOS) protein expression was upregulated in both newborn and adult hph-1 mice, but in the former there was evidence of enzyme uncoupling and higher tissue superoxide generation when compared with same age-matched animals. As opposed to the lack of strain differences in the U46619-induced force, the newborn hph-1 gastric muscle carbachol-induced contraction and nNOS-dependent relaxation were significantly reduced (P < 0.01). These group differences were not present in juvenile or adult mice. Preincubation with BH4 significantly enhanced the newborn hph-1, but not wild-type, gastric muscle contraction. In conclusion, changes compatible with gastroparesis are present in the newborn mouse model of pyloric stenosis. The role of BH4 deficiency and possibly associated gastroparesis in the pathogenesis of infantile pyloric stenosis warrants further investigation.
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Affiliation(s)
- Christopher Welsh
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
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Stackley KD, Beeson CC, Rahn JJ, Chan SSL. Bioenergetic profiling of zebrafish embryonic development. PLoS One 2011; 6:e25652. [PMID: 21980518 PMCID: PMC3183059 DOI: 10.1371/journal.pone.0025652] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 09/09/2011] [Indexed: 11/23/2022] Open
Abstract
Many debilitating conditions are linked to bioenergetic defects. Developing screens to probe the genetic and/or chemical basis for such links has proved intractable. Furthermore, there is a need for a physiologically relevant assay of bioenergetics in whole organisms, especially for early stages in life where perturbations could increase disease susceptibility with aging. Thus, we asked whether we could screen bioenergetics and mitochondrial function in the developing zebrafish embryo. We present a multiplexed method to assay bioenergetics in zebrafish embryos from the blastula period (3 hours post-fertilization, hpf) through to hatching (48 hpf). In proof of principle experiments, we measured respiration and acid extrusion of developing zebrafish embryos. We quantified respiratory coupling to various bioenergetic functions by using specific pharmacological inhibitors of bioenergetic pathways. We demonstrate that changes in the coupling to ATP turnover and proton leak are correlated with developmental stage. The multiwell format of this assay enables the user to screen for the effects of drugs and environmental agents on bioenergetics in the zebrafish embryo with high sensitivity and reproducibility.
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Affiliation(s)
- Krista D. Stackley
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Craig C. Beeson
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Jennifer J. Rahn
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Sherine S. L. Chan
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
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Namkung W, Thiagarajah JR, Phuan PW, Verkman AS. Inhibition of Ca2+-activated Cl- channels by gallotannins as a possible molecular basis for health benefits of red wine and green tea. FASEB J 2010; 24:4178-86. [PMID: 20581223 DOI: 10.1096/fj.10-160648] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
TMEM16A was found recently to be a calcium-activated Cl(-) channel (CaCC). CaCCs perform important functions in cell physiology, including regulation of epithelial secretion, cardiac and neuronal excitability, and smooth muscle contraction. CaCC modulators are of potential utility for treatment of hypertension, diarrhea, and cystic fibrosis. Screening of drug and natural product collections identified tannic acid as an inhibitor of TMEM16A, with IC(50) ∼ 6 μM and ∼100% inhibition at higher concentrations. Tannic acid inhibited CaCCs in multiple cell types but did not affect CFTR Cl(-) channels. Structure-activity analysis indicated the requirement of gallic or digallic acid substituents on a macromolecular scaffold (gallotannins), as are present in green tea and red wine. Other polyphenolic components of teas and wines, including epicatechin, catechin, and malvidin-3-glucoside, poorly inhibited CaCCs. Remarkably, a 1000-fold dilution of red wine and 100-fold dilution of green tea inhibited CaCCs by >50%. Tannic acid, red wine, and green tea inhibited arterial smooth muscle contraction and intestinal Cl(-) secretion. Gallotannins are thus potent CaCC inhibitors whose biological activity provides a potential molecular basis for the cardioprotective and antisecretory benefits of red wine and green tea.
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Affiliation(s)
- Wan Namkung
- Department of Medicine , University of California, San Francisco, CA 94143-0521, USA
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Toda N, Herman AG. Gastrointestinal Function Regulation by Nitrergic Efferent Nerves. Pharmacol Rev 2005; 57:315-38. [PMID: 16109838 DOI: 10.1124/pr.57.3.4] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Gastrointestinal (GI) smooth muscle responses to stimulation of the nonadrenergic noncholinergic inhibitory nerves have been suggested to be mediated by polypeptides, ATP, or another unidentified neurotransmitter. The discovery of nitric-oxide (NO) synthase inhibitors greatly contributed to our understanding of mechanisms involved in these responses, leading to the novel hypothesis that NO, an inorganic, gaseous molecule, acts as an inhibitory neurotransmitter. The nerves whose transmitter function depends on the NO release are called "nitrergic", and such nerves are recognized to play major roles in the control of smooth muscle tone and motility and of fluid secretion in the GI tract. Endothelium-derived relaxing factor, discovered by Furchgott and Zawadzki, has been identified to be NO that is biosynthesized from l-arginine by the constitutive NO synthase in endothelial cells and neurons. NO as a mediator or transmitter activates soluble guanylyl cyclase and produces cyclic GMP in smooth muscle cells, resulting in relaxation of the vasculature. On the other hand, NO-induced GI smooth muscle relaxation is mediated, not only by cyclic GMP directly or indirectly via hyperpolarization, but also by cyclic GMP-independent mechanisms. Numerous cotransmitters and cross talk of autonomic efferent nerves make the neural control of GI functions complicated. However, the findingsrelated to the nitrergic innervation may provide us a new way of understanding GI tract physiology and pathophysiology and might result in the development of new therapies of GI diseases. This review article covers the discovery of nitrergic nerves, their functional roles, and pathological implications in the GI tract.
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Affiliation(s)
- Noboru Toda
- Toyama Institute for Cardiovascular Pharmacology Research, Azuchi-machi, Chuo-ku, Osaka, Japan.
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Junor RW, Benjamin AR, Alexandrou D, Guggino SE, Walters DV. Lack of a role for cyclic nucleotide gated cation channels in lung liquid absorption in fetal sheep. J Physiol 2000; 523 Pt 2:493-502. [PMID: 10699091 PMCID: PMC2269800 DOI: 10.1111/j.1469-7793.2000.t01-3-00493.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
1. Late gestation fetal sheep were chronically catheterised in utero to allow measurement of the rate of production of lung liquid (Jv) from 132-143 days gestation (term, 147 days), and to test the hypothesis that cyclic nucleotide gated cation channels mediate a component of fetal lung liquid absorption. 2. In eight experiments, 0.5 microg min-1 adrenaline caused a significant (P < 0.005) reduction in Jv from +18. 12 +/- 3.52 to -10.27 +/- 5.26 ml h-1. Dichlorobenzamil (a blocker of cyclic nucleotide gated cation channels) at 1.5 x 10-5 M did not significantly inhibit the adrenaline-induced lung liquid absorption (Jv dichlorobenzamil, -5.77 +/- 2.78 ml h-1; P > 0.1) when the data were grouped, but did exert a significant gestational effect (r = 0. 90, P < 0.01). Subsequent addition of 10-4 M amiloride (a blocker of epithelial sodium channels) abolished the adrenaline-induced absorption of lung liquid (mean Jv amiloride, +6.45 +/- 1.59 ml h-1; P < 0.01 relative to Jv adrenaline and P < 0.005 relative to Jv dichlorobenzamil). 3. In seven experiments, 0.5 microg min-1 adrenaline caused a significant (P < 0.0005) reduction in Jv from +18.95 +/- 2. 98 to -10.08 +/- 3.75 ml h-1. Amiloride (10-4 M) inhibited the adrenaline response (Jv amiloride, +5.46 +/- 1.09 ml h-1; P < 0.005). However, subsequent addition of 1.5 x 10-5 M dichlorobenzamil had no additive effect to that of amiloride (Jv dichlorobenzamil, +4.58 +/- 0.93 ml h-1; P > 0.1). 4. In six experiments, the cGMP analogue 8-Br-cGMP at 10-4 M caused a significant (P < 0.05) reduction in Jv from +15.20 +/- 2.81 to +11.63 +/- 1.71 ml h-1. Amiloride (10-4 M) did not block the effect of 8-Br-cGMP (Jv amiloride, +14.00 +/- 2.49 ml h-1; not significantly different from 8-Br-cGMP). Subsequent addition of 1.5 x 10-5 M dichlorobenzamil also did not block the effect of 8-Br-cGMP (Jv dichlorobenzamil, +11.37 +/- 1.22 ml h-1; not significantly different from either Jv amiloride or Jv 8-Br-cGMP). 5. We conclude that, in fetal sheep, neither adrenaline nor cGMP stimulate lung liquid absorption by actions on cyclic nucleotide gated cation channels, and that the effect of cGMP on fetal lung liquid secretion is minor and does not involve epithelial sodium channels. The effect of dichlorobenzamil, when given before amiloride, was probably due to an action on amiloride sensitive epithelial sodium channels.
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Affiliation(s)
- R W Junor
- Department of Child Health, St George's Hospital Medical School, London SW17 0RE, UK.
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Rolfe VE, Levin RJ. Vagotomy inhibits the jejunal fluid secretion activated by luminal ileal Escherichia coli STa in the rat in vivo. Gut 1999; 44:615-9. [PMID: 10205195 PMCID: PMC1727489 DOI: 10.1136/gut.44.5.615] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND Escherichia coli heat stable enterotoxin (STa) is a major cause of secretory diarrhoea in humans. AIMS To assess the effects of instilling STa into the ileum on remote fluid secretion in the jejunum and colon in rats in vivo by a gravimetric technique. METHODS AND RESULTS Ileal STa (55 ng/ml) stimulated fluid secretion in both ileal and jejunal loops but not in the colon. The fluid secretion induced by ileal STa was inhibited by L-NAME (Nomega-nitro-L-arginine methyl ester, 40 mg/kg intraperitoneally) but not by D-NAME (Nomega-nitro-D-arginine methyl ester). Ileal carbachol (183 mg/ml) instilled into the lumen stimulated ileal secretion but not jejunal secretion, and was unaffected by L-NAME. Capsaicin (10 microM), instilled luminally with STa in the ileum, blocked both the ileal and jejunal fluid secretion. Acute bilateral vagotomy prevented luminal ileal STa from inducing jejunal fluid secretion but not from activating ileal fluid secretion. CONCLUSION Ileal E coli STa stimulates remote secretion in the rat jejunum but not in the colon, probably by a nitrinergic, vagal reflex mediated by C fibres. This neural pathway will amplify the action of the toxin in its generation of secretory diarrhoea.
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Affiliation(s)
- V E Rolfe
- Department of Biomedical Science, University of Sheffield, UK
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