Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0007570 (celiac disease)
 13,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transglutaminases are calcium-dependent enzymes that catalyze a post-translational modification of proteins through the formation of epsilon -(gamma-glutamyl)lysine bonds. Although specific roles for transglutaminases have been described, recent findings have provided evidence that dysregulation of transglutaminases may contribute to many pathological processes including celiac disease and neurodegenerative diseases. A crucial step in the elucidation of biological and pathological roles of transglutaminases requires the identification of protein substrates. A strategy based on a functional proteomic analysis was set up using two well-characterized biotinylated transglutaminase substrates as affinity probes: 5-(biotinamido)pentylamine and the synthetic biotinylated peptide TVQQEL, the amino- and acyl-donor probes, respectively. A pool of known tissue type transglutaminase protein substrates was selected in order to test the procedure. Results obtained in this paper indicate that the whole strategy can be successfully applied in order to identify transglutaminases protein substrates as well as the amino acid site sensitive toward enzyme activity.
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PMID:Analysis of transglutaminase protein substrates by functional proteomics. 1276

Transglutaminase (TG)-catalyzed cross-linking of both intracellular and extracellular proteins is an important biochemical event. However, increased concentrations of cross-linked proteins have been observed in many disorders. Moreover, TG-catalyzed modification of proteins might generate new self-antigens responsible for the autoimmune response, as in celiac disease. The identification of available substrates may offer an understanding of how the TG-catalyzed post-translational modification has an impact on physiology and disease. We used a proteomic approach to identify TG-modified protein targets in human intestinal epithelial cells to determine the extent to which transglutaminase specifically contributes to celiac disease. Two probes were used for endogenous TG activity: 5-(biotinamido)pentylamine, which represents the acyl-acceptor, and a biotinylated glutamine-containing peptide, which represents the acyl-donor. This approach identified >25 proteins, which range from 30,000 to 300,000 Daltons and can serve as acyl-acceptor and/or acyl-donor for transglutaminase. Some of them were known transglutaminase substrates, whereas others had not been previously identified. These targets include proteins involved in cytoskeletal network organization, folding of proteins, transport processes, and miscellaneous metabolic functions.
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PMID:Proteomics identification of acyl-acceptor and acyl-donor substrates for transglutaminase in a human intestinal epithelial cell line. Implications for celiac disease. 1279 66

Coeliac disease is a T-cell-mediated autoimmune disease of the small intestine that is induced by ingestion of gluten proteins from wheat, barley, or rye. We postulate that Candida albicans is a trigger in the onset of coeliac disease. The virulence factor of C albicans-hyphal wall protein 1 (HWP1)-contains aminoacid sequences that are identical or highly homologous to known coeliac disease-related alpha-gliadin and gamma-gliadin T-cell epitopes. HWP1 is a transglutaminase substrate, and is used by C albicans to adhere to the intestinal epithelium. Furthermore, tissue transglutaminase and endomysium components could become covalently linked to the yeast. Subsequently, C albicans might function as an adjuvant that stimulates antibody formation against HWP1 and gluten, and formation of autoreactive antibodies against tissue transglutaminase and endomysium.
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PMID:Is Candida albicans a trigger in the onset of coeliac disease? 1282 51

Recent efforts have piri-pointed a relevant sequence on gliadin, that may act as the immunodominant epitope in celiac disease. Independent reports from several leading laboratories identify a 33 amino acid segment spanning through residues 57-89, and excessively rich in proline and glutamine, as the putative epitope. A glutamine residue in position 65 is the site of deamidation by transglutaminase, promoting its recognition by DQ2-HLA. In addition, another gluten protein, glutenin, may be relevant to the pathogenesis in celiac disease.
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PMID:[The identification of the immunodominant gliadin epitope]. 1290 94

We report the case of a child with difficulties to control epilepsy and celiac disease, diagnosed soon after the onset of the seizure disorder. Seizure frequency and pattern, in addition to electroencephalogram record were suggestive of Lennox-Gastaut syndrome. Diagnosis of celiac disease was determined by positive anti-endomysium and anti-transglutaminase tests, and abnormal jejunal biopsy. Gluten-free diet, started soon after the diagnosis, led to progressive seizure control, allowing significant decrease in dosage of anti-epileptic drugs. This case corroborates the importance of serological screening tests for celiac disease, at least in patients with difficult to control epilepsy.
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PMID:Celiac disease and epilepsy: favorable outcome in a child with difficult to control seizures. 1295 65

Coeliac disease (CD) is known to have a strong genetic background. We analyzed the association between serological markers of CD and the -1087 IL10 and -308 TNFA gene polymorphisms in Swedish patients. A higher frequency of the TNF2 allele was present in the patients compared with the controls (p < 0.0001). The frequency of the AA genotype of the IL10 gene in the patients was unexpectedly higher in comparison with the controls (p < 0.05). The levels of IgA anti-endomysium and antitissue transglutaminase antibodies were associated with IL10 but not with TNFA genotype. The patients with the AA or GG -1087 IL10 genotypes had significantly lower levels of antibodies in comparison with those with the AG genotype (p < 0.05 to p < 0.0005). However, when divided according to potential level of IL-10 production, the group of potentially high IL-10 producers among the CD patients demonstrated significantly lower levels of antitissue transglutaminase antibodies compared to potentially low IL-10 producers (p = 0.01). Our results show a relationship between the levels of IgA antibodies involved in CD with the IL10 genotypes. This suggests a possible involvement of IL-10 in the development of the disease.
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PMID:Association of -1087 IL10 and -308 TNFA gene polymorphisms with serological markers of coeliac disease. 1295 21

Tissue transglutaminase (tTg) has been identified as the major autoantigen in coeliac disease (CD). ELISA methods have been developed for measuring the autoantibody. There are divergent reports on the effects of calcium on the antibody binding to tTg. Furthermore, zinc is a potent inhibitor of tTg. To better understand the role of transglutaminase in CD, we have studied the stability of commercial tTG, the effect of CD serum on tTg-activity and the effects of calcium and zinc on the antibody binding. The inclusion of calcium during the coating of the ELISA plates significantly increases the binding of the antibody, while zinc at physiological concentrations inhibits the binding. Moreover, our results show that commercial guinea pig liver Tg treated with calcium contains at least four major antigenic molecules and is a labile enzyme, which is degraded rapidly by contaminating proteases. Human serum contains anti-proteases that protect the enzyme. Probably, the labile character of commercial tTG explains the divergent reports on the effects of calcium on antibody binding. Finally, antibodies in serum from a CD patient do not seem to inhibit tTg activity. Hypothetically, low, intestinal Zn2+ -levels facilitate Ca2+-activation of tTg, which deamidates gliadin. A complex between tTg and modified gliadin forms the antigen and triggers the immune reaction leading to manifest CD. Hypozincaemia secondary to villous atrophy aggravates the induced disease.
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PMID:Biochemical and immuno-pathological aspects of tissue transglutaminase in coeliac disease. 1456 15

Gluten-free diet (GFD) plays a key role in the treatment of celiac disease (CD), but it is difficult to evaluate the effect of GFD on the improvement of villous architecture using sensitive, non-invasive tests. Aim of this study is to evaluate anti-transglutaminase (tTG) antibodies in the follow-up of CD to detect histologic recovery. We studied 42 consecutive patients with CD. In all the patients anti-tTG antibodies (evaluated by the enzyme linked immunosorbent assay method) and EGDscopy with multiple bioptic samples before GFD and then 6, 12, and 18 months after GFD were evaluated. For comparison, a sorbitol H2-breath test (H2-BT) and anti-endomysium (EMA) antibodies test were carried out concomitantly. Anti-tTG results were positive in 36 of 42 patients before GFD (80.95%), while they were positive in 11 of 34 (32.35%), 1 of 17 (5.88%), and 0 of 6 (0%) of patients with a persistence in histologic lesions 6, 12, and 18 months of GFD respectively, without any correlation with persistence of histologic lesions (P = NS). Also EMA failed to show correlation with improvement of histologic lesions. They were positive in 31 of 42 patients before GFD (73.80%), while they were positive in 18 of 34 (52.94%), 3 of 17 (17.64%), and 0 of 6 (0%) cases 6, 12, and 18 months of GFD respectively (P = NS). Regarding sorbitol H2-BT, it was positive in 40 of 42 (95.24%) patients before GFD, while it was positive in 31 of 34 (91.17%), 13 of 17 (76.47%), and 4 of 6 (50%) of patients with a persistence in histologic lesions 6, 12, and then 18 months after GFD starting (see Fig. 2, infra). So, anti-tTG and EMA were ineffective in assessing the histologic recovery at each follow-up visit (P = NS), while sorbitol H2-BT seems more effective than anti-tTG and EMA in this field (P < 0.0001 sorbitol H2-BT versus anti-tTG and versus EMA at 18 months after gluten withdrawal). Thirty-eight of 42 (90.47%) patients adhered to a strict GFD. Four patients were found to have occasional dietary transgression, and in all we noted a progressive decreasing of anti-tTG after 6 months of GFD and negative anti-tTG after 12 months of GFD, but sorbitol H2-BT persisted being positive during the entire follow-up. Intestinal damage persisted during the follow-up, despite anti-tTG and EMA negativity, and worsened in the presence of dietary lapses. Anti-tTG does not seem effective to assess histologic recovery in the follow-up of celiac patients after they have started GFD due to its poor correlation with histologic damage.
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PMID:Lack of usefulness of anti-transglutaminase antibodies in assessing histologic recovery after gluten-free diet in celiac disease. 1456 85

Celiac disease is a permanent immune-mediated food intolerance triggered by ingestion of wheat gliadins in genetically susceptible individuals. It has been reported that tissue transglutaminase plays an important role in the onset of celiac disease by converting specific glutamine residues within gliadin fragments into glutamic acid residues. This process increases binding affinity of gliadin peptides to HLA-DQ2/DQ8 molecules, thus enhancing the immune response. The aim of the present study was to achieve a detailed structural characterization of modifications induced by transglutaminase on gliadin peptides. Therefore, structural analyses were carried out on a recombinant alpha-gliadin and on a panel of 26 synthetic peptides, overlapping the complete protein sequence. Modified glutamine residues were identified by means of advanced mass-spectrometric methodologies on the basis of MALDI-TOF-MS and tandem mass spectrometry. Results led to the identification of 19 of 94 glutamine residues present in the recombinant alpha-gliadin, which were converted into glutamic acid residues by a transglutaminase-mediated reaction. This allowed us to achieve a global view of the modifications induced by the enzyme on this protein. Furthermore, results gathered could likely be utilized as relevant information for a better understanding of processes leading to T-cell recognition of gliadin peptides involved in celiac disease.
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PMID:Identification of transglutaminase-mediated deamidation sites in a recombinant alpha-gliadin by advanced mass-spectrometric methodologies. 1457 57

The contribution of age and/or sex to the transglutaminase (tTG) autoantibody response in celiac disease (CD) is not known. To gain insights into transglutaminase humoral autoimmunity at CD diagnosis, our aim was to characterize the autoimmune response against three tTG constructs [(full-length tTG(a.a.1-687), tTG(a.a.227-687), and tTG(a.a.473-687)] and to investigate into its relationship with CD patients' age and sex. One hundred seventy-five newly diagnosed CD patients (115 females and 60 males), subdivided into different groups according to age and sex, were studied using a serum 35S-radioimmunoassay. We found that among full-length tTG autoantibody-positive CD subjects (175/175), 50.9% (89/175) and 83.4% (146/175) had autoantibodies against tTG(227-687) and tTG(473-687) domains, respectively. Female patients of less than 4 years expressed tTG(227-687)Abs in significantly higher percentage and mean autoantibody titers vs. all other groups investigated, and tTG(473-687)Abs in significantly higher titers with respect to adult female patients. Our data identify a subset of CD patients showing a strong humoral tTG immunoreactivity at diagnosis, thus suggesting that age and sex influence the anti-tTG autoantibody response.
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PMID:Celiac disease-associated transglutaminase autoantibody target domains at diagnosis are age and sex dependent. 1469 46


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