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ABSTRACT: CD is an immune-mediated enteropathy caused by the ingestion of wheat gluten. The modification of gluten by intestinal tTGase plays a crucial role in CD pathogenesis. In this study, we observed that extensive transamidation of wheat flour with K-C(2)H(5) by mTGase yielded spf and K-gliadins fractions. By Western blot, we found that these modifications were associated with strongly reduced immune cross-reactivity. With the use of DQ8 tg mice as a model of gluten sensitivity, we observed a dramatic reduction in IFNγ production in gliadin-specific spleen cells challenged with spf and K-gliadins in vitro (n=12; median values: 813 vs. 29 and 99; control vs. spf and K-gliadins, P=0.012 for spf, and P=0.003 for K-gliadins). For spf, we also observed an increase in the IL-10/IFNγ protein ratio (n=12; median values: 0.3 vs. 4.7; control vs. spf, P=0.005). In intestinal biopsies from CD patients challenged in vitro with gliadins (n=10), we demonstrated further that K-gliadins dramatically reduced the levels of antigen-specific IFNγ mRNA in all specimens responsive to native gliadins (four of 10; P<0.05). As cytotoxic effects have been described for gliadins, we also studied GST and caspase-3 activities using the enterocytic Caco-2 cell line. We found that neither activities were modified by flour transamidation. Our results indicate that K-C(2)H(5) cross-linking via mTGase specifically affects gliadin immunogenicity, reversing the inducible inflammatory response in models of gluten sensitivity without affecting other aspects of the biological activity of gliadins.
Journal of leukocyte biology 10/2012; · 4.99 Impact Factor
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Giuseppe Mazzarella,
Virginia M Salvati,
Gaetano Iaquinto,
Rosita Stefanile,
Federica Capobianco,
Diomira Luongo, Paolo Bergamo,
Francesco Maurano,
Nicola Giardullo,
Basilio Malamisura,
Mauro Rossi
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ABSTRACT: A lifelong gluten-free diet (GFD) is mandatory for celiac disease (CD) but has poor compliance, justifying novel strategies. We found that wheat flour transamidation inhibited IFN-γ secretion by intestinal T cells from CD patients. Herein, the primary endpoint was to evaluate the ability of transamidated gluten to maintain GFD CD patients in clinical remission. Secondary endpoints were efficacy in prevention of the inflammatory response and safety at the kidney level, where reaction products are metabolized. In a randomized single blinded, controlled 90-day trial, 47 GFD CD patients received 3.7 g/day of gluten from nontransamidated (12) or transamidated (35) flour. On day 15, 75% and 37% of patients in the control and experimental groups, respectively, showed clinical relapse (P = 0.04) whereas intestinal permeability was mainly altered in the control group (50% versus 20%, P = 0.06). On day 90, 0 controls and 14 patients in the experimental group completed the challenge with no variation of antitransglutaminase IgA (P = 0.63), Marsh-Oberhuber grading (P = 0.08), or intestinal IFN-γ mRNA (P > 0.05). Creatinine clearance did not vary after 90 days of treatment (P = 0.46). In conclusion, transamidated gluten reduced the number of clinical relapses in challenged patients with no changes of baseline values for serological/mucosal CD markers and an unaltered kidney function.
Clinical and Developmental Immunology 01/2012; 2012:329150. · 1.84 Impact Factor
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ABSTRACT: The involvement of oxidative stress in gluten-induced toxicity has been evidenced in vitro and in clinical studies but has never been examined in vivo. We recently demonstrated the protective activity of conjugated linoleic acid (CLA), which functions by the activation of nuclear factor erythroid 2-related factor2 (Nrf2), a key transcription factor for the synthesis of antioxidant and detoxifying enzymes (phase 2). Here, we evaluate the involvement of nuclear factor erythroid 2-related factor2 in gliadin-mediated toxicity in human Caco-2 intestinal cells and in gliadin-sensitive human leukocyte antigen-DQ8 transgenic mice (DQ8) and the protective activity of CLA.
Gliadin effects in differentiated Caco-2 cells and in DQ8 mice, fed with a gliadin-containing diet with or without CLA supplementation, were evaluated by combining enzymatic, immunochemical, immunohistochemical, and quantitative real-time PCR (qRT-PCR) assays. Gliadin toxicity was accompanied by downregulation of phase 2 and elevates proteasome-acylpeptide hydrolase activities in vitro and in vivo. Notably, gliadin was unable to generate severe oxidative stress extent or pathological consequences in DQ8 mice intestine comparable to those found in celiac patients and the alterations produced were hampered by CLA.
The beneficial effects of CLA against the depletion of crucial intestinal cytoprotective defenses indicates a novel nutritional approach for the treatment of intestinal disease associated with altered redox homeostasis.
Molecular Nutrition & Food Research 09/2011; 55 Suppl 2:S248-56. · 4.30 Impact Factor
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ABSTRACT: Celiac disease (CD) is a gluten-sensitive enteropathy with an immune basis. We established the immune reactivity of the alcohol-soluble fraction from two minor cereals (tef and millet) and two pseudocereals (amaranth and quinoa) which are believed to be nontoxic based on taxonomy. Grains were examined in intestinal T-cell lines (iTCLs), cultures of duodenal explants from HLA-DQ2(+) CD patients and HLA-DQ8 transgenic mice for signs of activation. Our data indicated that tef, millet, amaranth, and quinoa did not show any immune cross-reactivity toward wheat gliadin, and therefore confirming their safety in the diet of CD patients.
Molecular Nutrition & Food Research 06/2011; 55(8):1266-70. · 4.30 Impact Factor
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ABSTRACT: Acylpeptide hydrolase (APEH), one of the four members of the prolyl oligopeptidase class, catalyses the removal of N-acylated amino acids from acetylated peptides and it has been postulated to play a key role in protein degradation machinery. Disruption of protein turnover has been established as an effective strategy to down-regulate the ubiquitin-proteasome system (UPS) and as a promising approach in anticancer therapy.Here, we illustrate a new pathway modulating UPS and proteasome activity through inhibition of APEH. To find novel molecules able to down-regulate APEH activity, we screened a set of synthetic peptides, reproducing the reactive-site loop of a known archaeal inhibitor of APEH (SsCEI), and the conjugated linoleic acid (CLA) isomers. A 12-mer SsCEI peptide and the trans10-cis12 isomer of CLA, were identified as specific APEH inhibitors and their effects on cell-based assays were paralleled by a dose-dependent reduction of proteasome activity and the activation of the pro-apoptotic caspase cascade. Moreover, cell treatment with the individual compounds increased the cytoplasm levels of several classic hallmarks of proteasome inhibition, such as NFkappaB, p21, and misfolded or polyubiquitinylated proteins, and additive effects were observed in cells exposed to a combination of both inhibitors without any cytotoxicity. Remarkably, transfection of human bronchial epithelial cells with APEH siRNA, promoted a marked accumulation of a mutant of the cystic fibrosis transmembrane conductance regulator (CFTR), herein used as a model of misfolded protein typically degraded by UPS. Finally, molecular modeling studies, to gain insights into the APEH inhibition by the trans10-cis12 CLA isomer, were performed.Our study supports a previously unrecognized role of APEH as a negative effector of proteasome activity by an unknown mechanism and opens new perspectives for the development of strategies aimed at modulation of cancer progression.
PLoS ONE 01/2011; 6(10):e25888. · 4.09 Impact Factor
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ABSTRACT: Celiac disease (CD) is an enteropathy triggered by gluten and mediated by CD4+ T cells. A complete understanding of CD immunopathogenesis has been hindered due to the lack of adequate in vivo models. Here, we explored the effect of the inhibition of COX by indomethacin in wheat gliadin-sensitized transgenic mice expressing the HLA-DQ8 heterodimer, a molecule associated with CD. Treated mice showed a gliadin-specific immune response with a significant reduction of villus height, not linked to crypt hyperplasia and to expansion of intraepithelial T cells. Notably, treated mice showed increased numbers of CD25+ and apoptotic cells in the lamina propria, whereas high basal levels of IFN-gamma secretion, along with a reduced gliadin-specific IL-2 expression were detected in MLN. Biochemical assessment of the lesion revealed increased mRNA of Lamb3 and Adamts2, encoding for ECM proteins, and enhanced activities of metalloproteinases MMP1, 2 and 7. We conclude that an intestinal sensitivity to gliadin, in connection with COX inhibition, caused a decreased villus height in DQ8 tg mice. The lesion was induced by a deregulated mucosal cell immunity to gliadin, thus triggering activation of a specific ECM protein pathway responsible for lamina propria remodeling.
European Journal of Immunology 09/2009; 39(12):3552-61. · 5.10 Impact Factor
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ABSTRACT: The gut-associated lymphoid tissue is deputed both to protect from infectious diseases and to evoke immune tolerance. Efficient responses need mucosal adjuvants: starting from cholera toxin, new variants of cholera toxin were developed depleted of toxicity. In addition, lipid colloidal particles, bacterial DNA, and probiotics have been experimented. Tolerance is currently induced by means of the B subunit of cholera toxin, whereas new strategies encompass the use of probiotics, expansion of regulatory T cells and blocking of paracellular entry of antigens. Finally, we report different approaches developed for celiac disease, an immune-mediated disease whose triggering antigen is known.
International Reviews Of Immunology 01/2009; 28(6):446-64. · 3.43 Impact Factor
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ABSTRACT: Antioxidant and cytoprotective enzymes (phase 2) exert protective activity against reactive oxygen species (ROS)-induced injury. We have recently shown how the beneficial effects of conjugated linoleic acid (CLA) in a mouse model of an autoimmune disease are parallel with the activation of phase 2 enzymes. In the present study we found that c9,t11-CLA isomer activates cytoprotective enzymes and down-regulates LPS- or gliadin-induced maturation in dendritic cells (DCs) obtained from a murine model of celiac disease. As expected, the enhancement of LPS-induced maturation (increased NFkappaB p65 nuclear translocation, CD86 expression and decreased CD11c+ cell number) was exacerbated by specific glutathione (GSH) inhibitor (buthionine sulphoximine; BSO). Conversely, the down-regulation of DC maturation by antioxidant N-acetylcysteine (NAC) was associated with the marked increase of intracellular thiol concentration. c9,t11-CLA activation of phase 2 enzymes in mouse DCs was observed first. Next, we found that the significant reduction of LPS- and gliadin-induced DC maturation in cultures pre-treated with c9,t11-CLA improved cellular redox status (decreased ROS and higher antioxidant defenses). Finally, the process of DC maturation triggered by gliadin, in contrast with that exhibited by LPS, was not associated with enhanced NFkappaB nuclear translocation and pro-inflammatory cytokines synthesis. These results demonstrate that c9,t11-CLA renders DCs more resistant to gliadin- or LPS-induced maturation, thus indicating that a cytoprotective mechanism elicited by c9,t11-CLA may modulate DC responsiveness.
Immunology Letters 06/2008; 117(2):181-90. · 2.53 Impact Factor
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Carmen Gianfrani,
Rosa A Siciliano,
Angelo M Facchiano,
Alessandra Camarca,
Maria F Mazzeo,
Susan Costantini,
Virginia M Salvati,
Francesco Maurano,
Giuseppe Mazzarella,
Gaetano Iaquinto, Paolo Bergamo,
Mauro Rossi
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ABSTRACT: Celiac disease is characterized by activation of HLA-DQ2/DQ8-restricted intestinal gluten-specific CD4(+) T cells. In particular, gluten becomes a better T-cell antigen following deamidation catalyzed by tissue transglutaminase. To date, the only available therapy is represented by adherence to a gluten-free diet. Here, we examined a new enzyme strategy to preventively abolish gluten activity.
Enzyme modifications of the immunodominant alpha-gliadin peptide p56-68 were analyzed by mass spectrometry, and peptide binding to HLA-DQ2 was simulated by modeling studies. Wheat flour was treated with microbial transglutaminase and lysine methyl ester; gliadin was subsequently extracted, digested, and deamidated. Gliadin-specific intestinal T-cell lines (iTCLs) were generated from biopsy specimens from 12 adult patients with celiac disease and challenged in vitro with different antigen preparations.
Tissue transglutaminase-mediated transamidation with lysine or lysine methyl ester of p56-68 or gliadin in alkaline conditions inhibited the interferon gamma expression in iTCLs; also, binding to DQ2 was reduced but not abolished, as suggested by in silico analysis. Lysine methyl ester was particularly effective in abrogating the activity of gliadin. Notably, a block in the response was observed when iTCLs were challenged with gliadin extracted from flour pretreated with microbial transglutaminase and lysine methyl ester.
Transamidation of wheat flour with a food-grade enzyme and an appropriate amine donor can be used to block the T cell-mediated gliadin activity. Considering the crucial role of adaptive immunity in celiac disease, our findings highlight the potential of the proposed treatment to prevent cereal toxicity.
Gastroenterology 09/2007; 133(3):780-9. · 11.68 Impact Factor
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ABSTRACT: Conjugated linoleic acid (CLA) exhibits anticancer and anti-inflammatory properties. Its ability to increase total GSH (GSH+GSSG) amount and gamma-glutamylcysteine ligase (gammaGCL) protein expression was recently associated with the inhibition of typical pathological signs in MRL/MpJ-Fas(lpr) mice (MRL/lpr). In the present study the ability of CLA to modulate oxidative stress and phase 2 enzyme activity in the same animal model was investigated. Disease severity was associated with age-dependent production of anti-double-stranded DNA antibodies (anti-dsDNA IgGs) and with enhanced extent of oxidative stress markers: reduced total GSH, increased protein 3-nitrotyrosines (3-NT), and protein-bound carbonyl (PC) amounts. To examine the effect of CLA on antioxidant status, CLA or olive oil (as control) was administered to pregnant MRL/lpr mice. Significantly higher total GSH and Trolox equivalent antioxidant capacity (TEAC) levels were measured in serum of CLA-treated dams (and their pups), as compared with controls. Finally, the antioxidant and chemopreventive properties of CLA were investigated in old MRL/lpr mice. Sera of CLA-treated mice contained higher concentrations of total GSH which were negatively correlated with the levels of oxidative stress markers. Moreover, increased GSH, gammaGCL, glutathione S-transferase (GSTs), and NAD(P)H:quinone oxidoreductase (NQO1) activities were measured in liver and spleen of CLA-treated animals. In conclusion our data indicate that the activation of detoxifying enzymes may be one of the mechanisms whereby dietary CLA down-regulates oxidative stress in MRL/lpr mice.
Free Radical Biology and Medicine 08/2007; 43(1):71-9. · 5.42 Impact Factor
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ABSTRACT: Conjugated linoleic acid (CLA), a naturally occurring peroxisome proliferator-activated receptor gamma (PPAR gamma) ligand, exhibits proapoptotic, immunomodulatory, and anticancer properties. In this study, we examined the biological effects of CLA administration in the MRL/MpJ-Fas(lpr) mouse, an animal model of systemic lupus erythematosus (SLE). We found that CLA exerted apparently opposed activities in in vitro experiments, depending on its concentration: 100 microM CLA downregulated IFN gamma synthesis and cell proliferation of splenocytes, in association with apoptosis induction and a decrease of intracellular thiols (GSH + GSSG), whereas 25 microM CLA did not significantly influence cell proliferation but enhanced the expression of gamma-glutamylcysteine ligase catalytic subunit (GCLC) and intracellular GSH concentration. Interestingly, the antiproliferative effect at 100 microM was not inhibited by the PPAR gamma antagonist GW9662. In vivo, CLA administration drastically reduced SLE signs (splenomegaly, autoantibodies, and cytokine synthesis), a condition paralleled by the enhancement of GCLC expression and intracellular GSH content. Moreover, CLA administration significantly downregulated nuclear factor kappaB activity independent of PPAR gamma activation and apoptosis induction. In conclusion, enhanced GSH content and GCLC expression in CLA-treated mice suggest a novel biochemical mechanism underlying its immunomodulatory activity and the beneficial effects on murine SLE signs.
The Journal of Lipid Research 12/2006; 47(11):2382-91. · 5.56 Impact Factor
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ABSTRACT: Deoxynivalenol (DON) and its hydroxylated form nivalenol (NIV) are Fusarium mycotoxins that occur in cereal grains alone or in combination. Several studies have shown that these metabolites affect lymphocyte functions. However, the molecular mechanisms underlying their activities are still partially known. To address this issue, we examined the influence of NIV and DON in modulating IFNgamma, IL-2 and IL-8 mRNA levels in Jurkat T cells. In PMA/ionomycin stimulated cells, pre-incubated with increasing concentrations of NIV, transcription was induced in the range 0.06-2 microM; higher concentrations of NIV were found non-stimulating (4 microM) or inhibitory (8 microM) for IFNgamma and IL-2 whereas IL-8 was still induced. DON administration elicited a similar profile for IL-8 and IFNgamma, whilst IL-2 mRNA was induced in a broader range of concentrations. Combination of NIV and DON at 1:1 and 1:10 ratios essentially restored the cytokine transcriptional pattern observed with NIV alone but the level of transcripts, with the exception of IL-8, peaked at lower concentrations suggesting interactive effects. Moreover both mycotoxins caused inhibition of cell proliferation, mediated by induction of apoptosis, confirming previous results and highlighting the usefulness of Jurkat as a T-cell model to study the effects of mycotoxins on the immune functions in humans.
Cytokine 11/2006; 36(1-2):75-82. · 3.02 Impact Factor
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ABSTRACT: Synthetic Conjugated Linoleic Acid mixture (CLA; c9,t11; t10,c12-18:2) has been previously shown to inhibit growth, and enhance apoptosis and IL-2 mRNA synthesis in human lymphoblastic Jurkat T-cells. In this study, two different butterfat types were evaluated and compared for their effects on Jurkat cell viability, oxidative stress, pro-apoptotic activity, and cytokine synthesis: the conventionally produced butterfat (CBF), and organic butterfat (OBF) containing significantly higher amounts of c9,t11 (Rumenic Acid, RA), trans-vaccenic acid (VA; t11-18:1), alpha-linolenic acid (ALA), and lower levels of linoleic acid (LA). Results from cell treatment with both butterfat mixtures showed comparable oxidative stress (superoxide production, intracellular GSH depletion,and lipid peroxides yield), NADPH oxidase activation, cytotoxicity (LDH release), and IL-2 transcript level, whereas the effects of enhanced growth-inhibitory and pro-apoptotic activities were associated with OBF treatment. To then investigate each butterfat-induced effect caused by RA, VA, LA, and ALA, cells were exposed to synthetic FA concentrations similar to those from the different butterfats. Higher oxidative stress (superoxide production, intracellular GSH depletion) was induced by alpha-linolenic (ALA) and linoleic (LA) incubation (P<0.01) and superoxide production was suppressed by specific PKCalpha inhibitor (Gö 6976) and linked to increased toxicity and IL-2 synthesis inhibition. By contrast, cell treatment with RA increased apoptosis and IL-2 synthesis. These results suggest that a supply of ALA and LA is responsible for BF-induced oxidative stress via PKCalpha-NADPH oxidase pathway, and that enhanced antiproliferative effects in OBF treated cells is essentially determined by RA-induced pro-apoptotic activity.
Journal of Cellular Biochemistry 11/2005; 96(2):349-60. · 2.87 Impact Factor
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ABSTRACT: The pro-apoptotic ability of conjugated linoleic acid (CLA) has been partly accounted for its anticarcinogenic effect although the precise mechanism of action remains elusive. In this study we characterized the biochemical events governing CLA-mediated apoptosis in Jurkat T cells. CLA induced a time-and dose-dependent activation of caspase-3. Pre-treatment with antioxidant molecules (trolox and quercetin), antioxidant enzymes (catalase and superoxide dismutase) metal chelator (EDTA), reducing agent (N-acetyl-L-cysteine), NADPH oxidase or protein kinase C (PKC) inhibitor (diphenyleneiodinium and G 6976, respectively) suppressed CLA-mediated caspase-3 activation. Moreover, CLA treatment increased the NADPH oxidase activity and depleted the intracellular pool of reduced glutathione. These results suggested that CLA can trigger apoptosis through an oxidative stress mediated by the PKC/NADPH oxidase pathway. The proposed mechanism provides a new insight into the anticancer activity of CLA.
Cellular Physiology and Biochemistry 02/2004; 14(1-2):57-64. · 2.86 Impact Factor
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ABSTRACT: Conjugated linoleic acid (CLA) has shown beneficial properties in animal models including anti-cancer, anti-atherogenic and anti-diabetic effects, while contrasting immunological effects were reported. While its anti-inflammatory activity has been associated to inhibition of arachidonic acid biosynthesis and to peroxisome proliferator-activated receptors (PPARs) activity, the molecular pathways underlying its immunoenhancing activity are essentially unknown. The aim of our study was to examine whether CLA showed specific effects in vitro on a T cell model, represented by the Jurkat cell line. CLA was found non toxic for Jurkat in the range 50-200 microM, as assessed by LDH release; however, incubation with 50 microM CLA was associated to a significant inhibitory effect on cell proliferation. The analysis of IL-2 and IFN-gamma transcript levels, produced in stimulated Jurkat cells, showed an increased expression of both cytokines in CLA-treated cells. Interestingly, the increased induction of IL-2 but not of IFN-gamma mRNA, could be suppressed by co-incubation with Gö 6976, a protein kinase C (PKC) inhibitor. Co-incubation with superoxide dismutase (SOD) or N-acetyl-L-cysteine (NAC) restored the basal levels of RNA synthesis for both cytokines. Taken together, these results suggest a specific role for dietary CLA in the modulation of the immune response in a T cell line model that is mediated, at least in part, by PKC and through the production of oxidative molecules.
Immunology Letters 01/2004; 90(2-3):195-201. · 2.53 Impact Factor
