The Combination of Gold and Silver Food Nanoparticles with Gluten Peptides Alters the Autophagic Pathway in Intestinal Crypt-like Cells

Metallic nanoparticles (mNPs) are widely used as food additives and can interact with gliadin triggering an immune response, but evaluation of the effects on crypts, hypertrophic in celiac subjects, is still lacking. This study evaluated the effects of gold and silver mNPs in combination with gliadin on crypt-like cells (HIEC-6). Transmission electron microscopy (TEM) was used to evaluate gliadin-mNP aggregates in cells. Western blot and immunofluorescence analysis assessed autophagy-related molecule levels (p62, LC3, beclin-1, EGFR). Lysosome functionality was tested with acridine orange (AO) and Magic Red assays. TEM identified an increase in autophagic vacuoles after exposure to gliadin + mNPs, as also detected by significant increments in LC3-II and p62 expression. Immunofluorescence confirmed the presence of mature autophagosomes, showing LC3 and p62 colocalization, indicating an altered autophagic flux, further assessed with EGFR degradation, AO and Magic Red assays. The results showed a significant reduction in lysosomal enzyme activity and a modest reduction in acidity. Thus, gliadin + mNPs can block the autophagic flux inducing a lysosomal defect. The alteration of this pathway, essential for cell function, can lead to cell damage and death. The potential effects of this copresence in food should be further characterized to avoid a negative impact on celiac disease subjects.

Current Therapeutical Approaches Targeting Lipid Metabolism in NAFLD

Nonalcoholic fatty liver disease (NAFLD, including nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH)) is a high-prevalence disorder, affecting about 1 billion people, which can evolve to more severe conditions like cirrhosis or hepatocellular carcinoma. NAFLD is often concomitant with conditions of the metabolic syndrome, such as central obesity and insulin-resistance, but a specific drug able to revert NAFL and prevent its evolution towards NASH is still lacking. With the liver being a key organ in metabolic processes, the potential therapeutic strategies are many, and range from directly targeting the lipid metabolism to the prevention of tissue inflammation. However, side effects have been reported for the drugs tested up to now. In this review, different approaches to the treatment of NAFLD are presented, including newer therapies and ongoing clinical trials. Particular focus is placed on the reverse cholesterol transport system and on the agonists for nuclear factors like PPAR and FXR, but also drugs initially developed for other conditions such as incretins and thyromimetics along with validated natural compounds that have anti-inflammatory potential. This work provides an overview of the different therapeutic strategies currently being tested for NAFLD, other than, or along with, the recommendation of weight loss.

The mode of dexamethasone decoration influences avidin-nucleic-acid-nano-assembly organ biodistribution and in vivo drug persistence

Avidin-Nucleic-Acid-NanoASsemblies (ANANAS) possess natural tropism for the liver and, when loaded with dexamethasone, reduce clinical progression in an autoimmune hepatitis murine model. Here, we investigated the linker chemistry (hydrazide-hydrazone, Hz-Hz, or carbamate hydrazide-hydrazone, Cb-Hz bond) and length (long, 5 kDa PEG, or short, 5-6 carbons) in biotin-dexamethasone conjugates used for nanoparticle decoration through in vitro and in vivo studies. All four newly synthesized conjugates released the drug at acidic pH only. In vitro, the Hz-Hz and the PEG derivatives were less stable than the Cb-Hz and the short chain ones, respectively. Once injected in healthy mice, dexamethasone location in the PEGylated ANANAS outer layer favors liver penetration and resident macrophages uptake, while drug Hz-Hz, but not Cb-Hz, short spacing prolongs drug availability. In conclusion, the tight modulation of ANANAS decoration can significantly influence the host interaction, paving the way for the development of steroid nanoformulations suitable for different pharmacokinetic profiles.

Celiac disease: From genetics to epigenetics

Celiac disease (CeD) is a multifactorial autoimmune disorder spread worldwide. The exposure to gluten, a protein found in cereals like wheat, barley and rye, is the main environmental factor involved in its pathogenesis. Even if the genetic predisposition represented by HLA-DQ2 or HLA-DQ8 haplotypes is widely recognised as mandatory for CeD development, it is not enough to explain the total predisposition for the disease. Furthermore, the onset of CeD comprehend a wide spectrum of symptoms, that often leads to a delay in CeD diagnosis. To overcome this deficiency and help detecting people with increased risk for CeD, also clarifying CeD traits linked to disease familiarity, different studies have tried to make light on other predisposing elements. These were in many cases genetic variants shared with other autoimmune diseases. Since inherited traits can be regulated by epigenetic modifications, also induced by environmental factors, the most recent studies focused on the potential involvement of epigenetics in CeD. Epigenetic factors can in fact modulate gene expression with many mechanisms, generating more or less stable changes in gene expression without affecting the DNA sequence. Here we analyze the different epigenetic modifications in CeD, in particular DNA methylation, histone modifications, non-coding RNAs and RNA methylation. Special attention is dedicated to the additional predispositions to CeD, the involvement of epigenetics in developing CeD complications, the pathogenic pathways modulated by epigenetic factors such as microRNAs and the potential use of epigenetic profiling as biomarker to discriminate different classes of patients.

Anti-SARS-CoV-2 immunoglobulin profile in patients with celiac disease living in a high incidence area

BACKGROUND AND AIM

How symptoms and antibodies related to SARS-CoV-2 infection develop in patients with celiac disease (CD) is unclear. We aimed to investigate the impact of SARS-CoV-2 infection in CD patients.

METHODS

CD patients were interviewed about the development of COVID-19 symptoms, compliance with anti-virus measures and adherence to a gluten-free diet (GFD). The presence of anti-SARS-CoV-2 IgG and IgA (anti-RBD and N proteins) was compared to that in non-CD subjects. Expression of the duodenal ACE2 receptor was investigated. When available, data on duodenal histology, anti-tissue transglutaminase IgA (tTGA), comorbidities and GFD adherence were analyzed.

RESULTS

Of 362 CD patients, 42 (12%) reported COVID-19 symptoms and 21% of these symptomatic patients presented anti-SARS-CoV-2 Ig. Overall, 18% of CD patients showed anti-SARS-CoV-2 Ig versus 25% of controls (p = 0.18). CD patients had significantly lower levels of anti-N IgA. tTGA, duodenal atrophy, GFD adherence or other comorbidities did not influence symptoms and/or antibodies. The ACE2 receptor was detected in the non-atrophic duodenal mucosa of patients; atrophy was associated with lower expression of the ACE2 receptor.

CONCLUSION

CD patients have an anti-SARS-CoV-2 Ig profile similar to non-celiac controls, except for anti-N IgA. No risk factors were identified among CD parameters and GFD adherence.

Circulating miRNAs as Potential Biomarkers for Celiac Disease Development

Background & Aims

Celiac disease (CeD), an immune-mediated disease with enteropathy triggered by gluten, affects ~1% of the general European population. Currently, there are no biomarkers to predict CeD development. MicroRNAs (miRNAs) are short RNAs involved in post-transcriptional gene regulation, and certain disease- and stage-specific miRNA profiles have been found previously. We aimed to investigate whether circulating miRNAs can predict the development of CeD.

Methods

Using next-generation miRNA-sequencing, we determined miRNAs in >200 serum samples from 53 participants of the PreventCD study, of whom 33 developed CeD during follow-up. Following study inclusion at 3 months of age, samples were drawn at predefined ages, diagnosis (first anti-transglutaminase antibody (TGA) positivity or diagnostic biopsy) and after the start of a gluten-free diet (GFD). This allowed identification of circulating miRNAs that are deregulated before TGA positivity. For validation of the biomarkers for CeD and GFD response, two additional cohorts were included in subsequent meta-analyses. Additionally, miRNAs were measured in duodenal biopsies in a case-control cohort.

Results

53 circulating miRNAs were increased (27) or decreased (26) in CeD versus controls. We assessed specific trends in these individual miRNAs in the PreventCD cohort by grouping the pre-diagnostic samples of the CeD patients (all had negative TGA) by how close to seroconversion (first sample positive TGA) the samples were taken. 8/53 miRNAs differed significantly between controls and samples taken <1 year before TGA positivity: miR-21-3p, miR-374a-5p, 144-3p, miR-500a-3p, miR-486-3p let-7d-3p, let-7e-5p and miR-3605-3p. 6/26 downregulated miRNAs reconstituted upon GFD, including miR-150-5p/-3p, whereas no upregulated miRNAs were downregulated upon GFD. 15/53 biomarker candidates also differed between CeD biopsies and controls, with a concordant direction, indicating that these circulating miRNAs might originate from the intestine.

Conclusions

We identified 53 circulating miRNAs that are potential early biomarkers for CeD, of which several can be detected more than a year before TGA positivity and some start to normalize upon GFD.

Impact of COVID-19 on inflammatory bowel disease practice and perspectives for the future

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); since its first description in December 2019, it has rapidly spread to a global pandemic. Specific concerns have been raised concerning patients with inflammatory bowel diseases (IBD), which are chronic autoimmune inflammatory disorders of the gut that frequently require immunosuppressive and biological therapies to control their activity. Accumulating evidence has so far demonstrated that patients with IBD are not at increased risk of contracting severe acute respiratory syndrome coronavirus 2 infection. As for the general population, the identified risk factors for severe COVID-19 course among IBD patients have been established to be advanced age and the presence of comorbidities. Treatment with high-dose corticosteroids has also been associated with an increased risk of death in IBD patients with COVID-19. Information on COVID-19 is constantly evolving, with data growing at a rapid pace. This will guarantee better knowledge and stronger evidence to help physicians in the choice of the best therapeutic approach for each patient, concurrently controlling for the risk of IBD disease under treatment and the risk of COVID-19 adverse outcomes and balancing the two. Moreover, the impact of the enormous number of severe respiratory patients on healthcare systems and facilities has led to an unprecedented redeployment of healthcare resources, significantly impacting the care of patients with chronic diseases. In this newly changed environment, the primary aim is to avoid harm whilst still providing adequate management. Telemedicine has been applied and is strongly encouraged for patients without the necessity of infusion therapy and whose conditions are stable. The severe acute respiratory syndrome coronavirus 2 pandemic has already revolutionized the management of patients with chronic immune-mediated diseases such as IBD. Direct and indirect effects of the COVID-19 pandemic will be present for some time. This is the reason why continuous research, rapid solutions and constantly updated guidelines are of utmost importance. The aim of the present review is, therefore, to point out what has been learned so far as well as to pinpoint the unanswered questions and perspectives for the future.

Accuracy of Transient Elastography in Assessing Fibrosis at Diagnosis in Naïve Patients With Primary Biliary Cholangitis: A Dual Cut-Off Approach

BACKGROUND AND AIMS

Liver fibrosis holds a relevant prognostic meaning in primary biliary cholangitis (PBC). Noninvasive fibrosis evaluation using vibration-controlled transient elastography (VCTE) is routinely performed. However, there is limited evidence on its accuracy at diagnosis in PBC. We aimed to estimate the diagnostic accuracy of VCTE in assessing advanced fibrosis (AF) at disease presentation in PBC.

APPROACH AND RESULTS

We collected data from 167 consecutive treatment-naïve PBC patients who underwent liver biopsy (LB) at diagnosis at six Italian centers. VCTE examinations were completed within 12 weeks of LB. Biopsies were scored by two blinded expert pathologists, according to the Ludwig system. Diagnostic accuracy was estimated using the area under the receiver operating characteristic curves (AUROCs) for AF (Ludwig stage ≥III). Effects of biochemical and clinical parameters on liver stiffness measurement (LSM) were appraised. The derivation cohort consisted of 126 patients with valid LSM and LB; VCTE identified patients with AF with an AUROC of 0.89. LSM cutoffs ≤6.5 and >11.0 kPa enabled to exclude and confirm, respectively, AF (negative predictive value [NPV] = 0.94; positive predictive value [PPV] = 0.89; error rate = 5.6%). These values were externally validated in an independent cohort of 91 PBC patients (NPV = 0.93; PPV = 0.89; error rate = 8.6%). Multivariable analysis found that the only parameter affecting LSM was fibrosis stage. No association was found with BMI and liver biochemistry.

CONCLUSIONS

In a multicenter study of treatment-naïve PBC patients, we identified two cutoffs (LSM ≤6.5 and >11.0 kPa) able to discriminate at diagnosis the absence or presence, respectively, of AF in PBC patients, with external validation. In patients with LSM between these two cutoffs, VCTE is not reliable and liver biopsy should be evaluated for accurate disease staging. BMI and liver biochemistry did not affect LSMs.

Immune-Mediated Drug-Induced Liver Injury: Immunogenetics and Experimental Models

Drug-induced liver injury (DILI) is a challenging clinical event in medicine, particularly because of its ability to present with a variety of phenotypes including that of autoimmune hepatitis or other immune mediated liver injuries. Limited diagnostic and therapeutic tools are available, mostly because its pathogenesis has remained poorly understood for decades. The recent scientific and technological advancements in genomics and immunology are paving the way for a better understanding of the molecular aspects of DILI. This review provides an updated overview of the genetic predisposition and immunological mechanisms behind the pathogenesis of DILI and presents the state-of-the-art experimental models to study DILI at the pre-clinical level.

Gliadin, through the Activation of Innate Immunity, Triggers lncRNA NEAT1 Expression in Celiac Disease Duodenal Mucosa

Celiac disease (CD) is an autoimmune enteropathy arising in genetically predisposed subjects exposed to gluten, which activates both innate and adaptive immunity. Although the pathogenesis is common to all patients, the clinical spectrum is quite variable, and differences could be explained by gene expression variations. Among the factors able to affect gene expression, there are lncRNAs. We evaluated the expression profile of 87 lncRNAs in CD vs. healthy control (HC) intestinal biopsies by RT-qPCR array. Nuclear enriched abundant transcript 1 (NEAT1) and taurine upregulated gene 1 (TUG1) were detected as downregulated in CD patients at diagnosis, but their expression increased in biopsies of patients on a gluten-free diet (GFD) exposed to gluten. The increase in NEAT1 expression after gluten exposure was mediated by IL-15 and STAT3 activation and binding to the NEAT1 promoter, as demonstrated by gel shift assay. NEAT1 is localized in the nucleus and can regulate gene expression by sequestering transcription factors, and it has been implicated in immune regulation and control of cell proliferation. The demonstration of its regulation by gluten thus also supports the role of lncRNAs in CD and prompts further research on these RNAs as gene expression regulators.

How to manage celiac disease and gluten-free diet during the COVID-19 era: proposals from a tertiary referral center in a high-incidence scenario

The outbreak of COVID-19 and SARS-CoV-2 infection is spreading worldwide as the first coronavirus pandemic. The clinical picture is variable but flu-like symptoms are common with bilateral interstitial pneumonia being the most frightening presentation. No specific therapies nor vaccine have been developed to date and the only way to limit the virus diffusion is by modifying one's lifestyle limiting social life and following strict hygienic precautions. No data is available on the risk of COVID-19 and its outcomes in celiac disease (CeD). The restrictions applied to counter COVID-19 can impact on CeD treatment and gluten-free dieting, the only available therapy for CeD. With the present manuscript, we aim to support gastroenterologists and nutritionists in the management of CeD patients in the new pandemic scenario, being conscious that availability and local situations are extremely various.

Tissue alarmins and adaptive cytokine induce dynamic and distinct transcriptional responses in tissue-resident intraepithelial cytotoxic T lymphocytes

The respective effects of tissue alarmins interleukin (IL)-15 and interferon beta (IFNβ), and IL-21 produced by T cells on the reprogramming of cytotoxic T lymphocytes (CTLs) that cause tissue destruction in celiac disease is poorly understood. Transcriptomic and epigenetic profiling of primary intestinal CTLs showed massive and distinct temporal transcriptional changes in response to tissue alarmins, while the impact of IL-21 was limited. Only anti-viral pathways were induced in response to all the three stimuli, albeit with differences in dynamics and strength. Moreover, changes in gene expression were primarily independent of changes in H3K27ac, suggesting that other regulatory mechanisms drive the robust transcriptional response. Finally, we found that IL-15/IFNβ/IL-21 transcriptional signatures could be linked to transcriptional alterations in risk loci for complex immune diseases. Together these results provide new insights into molecular mechanisms that fuel the activation of CTLs under conditions that emulate the inflammatory environment in patients with autoimmune diseases.

Food additives can act as triggering factors in celiac disease: Current knowledge based on a critical review of the literature

Celiac disease (CeD) is an autoimmune disorder, mainly affecting the small intestine, triggered by the ingestion of gluten with the diet in subjects with a specific genetic status. The passage of gluten peptides through the intestinal barrier, the uptake by antigen presenting cells and their presentation to T cells represent essential steps in the pathogenesis of the disease. CeD prevalence varies in different populations, but a tendency to increase has been observed in various studies in recent years. A higher amount of gluten in modern grains could explain this increased frequency, but also food processing could play a role in this phenomenon. In particular, the common use of preservatives such as nanoparticles could intervene in the pathogenesis of CeD, due to their possible effect on the integrity of the intestinal barrier, immune response or microbiota. In fact, these alterations have been reported after exposure to metal nanoparticles, which are commonly used as preservatives or to improve food texture, consistency and color. This review will focus on the interactions between several food additives and the intestine, taking into account data obtained in vitro and in vivo, and analyzing their effect in respect to the development of CeD in genetically predisposed individuals.

Dexamethasone Conjugation to Biodegradable Avidin-Nucleic-Acid-Nano-Assemblies Promotes Selective Liver Targeting and Improves Therapeutic Efficacy in an Autoimmune Hepatitis Murine Model

Steroids are the standard therapy for autoimmune hepatitis (AIH) but the long-lasting administration is hampered by severe side effects. Methods to improve the tropism of the drug toward the liver are therefore required. Among them, conjugation to nanoparticles represents one possible strategy. In this study, we exploited the natural liver tropism of Avidin-Nucleic-Acid-Nano-Assemblies (ANANAS) to carry dexamethasone selectively to the liver in an AIH animal model. An acid-labile biotin-hydrazone linker was developed for reversible dexamethasone loading onto ANANAS. The biodistribution, pharmacokinetics and efficacy of free and ANANAS-linked dexamethasone (ANANAS-Hz-Dex) in healthy and AIH mice were investigated upon intraperitoneal administration. In ANANAS-treated animals, the free drug was detected only in the liver. Super-resolution microscopy showed that nanoparticles segregate inside lysosomes of liver immunocompetent cells, mainly involved in AIH progression. In agreement with these observational results, chronic low-dose treatment with ANANAS-Hz-Dex reduced the expression of liver inflammation markers and, in contrast to the free drug, also the levels of circulating AIH-specific autoantibodies. These data suggest that the ANANAS carrier attenuates AIH-related liver damage without drug accumulation in off-site tissues. The safety and biodegradability of the ANANAS carrier make this formulation a promising tool for the treatment of autoimmune liver disorders.

Hepcidin regulation in a mouse model of acute hypoxia

OBJECTIVE

During hypoxia, hepcidin expression is inhibited to allow iron mobilization to sustain erythropoietic expansion. We analyzed molecular mechanisms underlying hypoxia-induced hepcidin inhibition in an in vivo model of acute hypoxia.

METHODS

Mice were kept under normal or hypoxic conditions for 6 hours and 15 hours and treated with α-PDGF-BB antibody or PDGF-BB receptor inhibitor. Blood, liver, spleen, and bone marrow were collected to extract RNA and protein or to quantify EPO and PDGF-BB. mRNA and protein levels were assessed by RT-PCR and Western blot.

RESULTS

Hepcidin was strongly inhibited at 15 hours, and this downregulation followed erythropoiesis activation and upregulation of several growth factors. PDGF-BB, erythroferrone, GDF15, and TWSG1 were upregulated by hypoxia in the bone marrow, but not in spleen or liver. Inactivation of PDGF-BB or its receptor suppressed the hypoxia-induced hepcidin inhibition.

CONCLUSION

Spleen and liver are not involved in the early stages of hypoxia-induced hepcidin downregulation. Our data support the role of PDGF-BB and probably also of erythroferrone in the recruitment of iron for erythropoiesis in the hypoxia setting. The rapid normalization of all the erythroid factors against persistent hepcidin suppression suggests that other signals are involved that should be clarified in future studies.

miRNAs affect the expression of innate and adaptive immunity proteins in celiac disease

OBJECTIVES

microRNAs (miRNAs) are short RNAs that regulate gene expression in various processes, including immune response. Altered immune response is a pivotal event in the pathogenesis of celiac disease (CD), and miRNAs could have a role in modulating both innate and adaptive response to gluten in celiac patients.

METHODS

We compared miRNA profiles in duodenal biopsies of controls and CD patients by miRNA array. Differentially expressed miRNAs were validated in controls, Marsh 3A-B, and Marsh 3C patients by quantitative PCR (qPCR). Target gene expression was assessed by qPCR, western blotting, and immunohistochemistry, and the effect of gliadin was evaluated by in vitro stimulation experiments on duodenal biopsies.

RESULTS

Seven miRNAs were identified as significantly downregulated in the duodenum of adult CD patients as compared with controls. qPCR validated the decreased expression of miR-192-5p, miR-31-5p, miR-338-3p, and miR-197, in particular in patients with more severe histological lesions (Marsh 3C). In silico analysis of possible miRNA targets identified several genes involved in innate and adaptive immunity. Among these, chemokine C-X-C motif ligand 2 (CXCL2) and NOD2 showed significantly increased mRNA and protein level in Marsh 3C patients and a significant inverse correlation with the regulatory miR-192-5p. In addition, forkhead box P3 (FOXP3), Run-related transcription factor 1, and interleukin-18 (targets of miR-31-5p, miR-338-3p, and miR-197, respectively) showed upregulation in CD patients. Furthermore, alterations in CXCL2 and NOD2, FOXP3, miR-192-5p, and miR-31-5p expression were triggered by gliadin exposure in CD patients.

CONCLUSIONS

miRNA expression is significantly altered in duodenal mucosa of CD patients, and this alteration can increase the expression of molecules involved in immune response.

Fine mapping of the celiac disease-associated LPP locus reveals a potential functional variant

Using the Immunochip for genotyping, we identified 39 non-human leukocyte antigen (non-HLA) loci associated to celiac disease (CeD), an immune-mediated disease with a worldwide frequency of ∼1%. The most significant non-HLA signal mapped to the intronic region of 70 kb in the LPP gene. Our aim was to fine map and identify possible functional variants in the LPP locus. We performed a meta-analysis in a cohort of 25 169 individuals from six different populations previously genotyped using Immunochip. Imputation using data from the Genome of the Netherlands and 1000 Genomes projects, followed by meta-analysis, confirmed the strong association signal on the LPP locus (rs2030519, P = 1.79 × 10(-49)), without any novel associations. The conditional analysis on this top SNP-indicated association to a single common haplotype. By performing haplotype analyses in each population separately, as well as in a combined group of the four populations that reach the significant threshold after correction (P < 0.008), we narrowed down the CeD-associated region from 70 to 2.8 kb (P = 1.35 × 10(-44)). By intersecting regulatory data from the ENCODE project, we found a functional SNP, rs4686484 (P = 3.12 × 10(-49)), that maps to several B-cell enhancer elements and a highly conserved region. This SNP was also predicted to change the binding motif of the transcription factors IRF4, IRF11, Nkx2.7 and Nkx2.9, suggesting its role in transcriptional regulation. We later found significantly low levels of LPP mRNA in CeD biopsies compared with controls, thus our results suggest that rs4686484 is the functional variant in this locus, while LPP expression is decreased in CeD.

Improving coeliac disease risk prediction by testing non-HLA variants additional to HLA variants

BACKGROUND

The majority of coeliac disease (CD) patients are not being properly diagnosed and therefore remain untreated, leading to a greater risk of developing CD-associated complications. The major genetic risk heterodimer, HLA-DQ2 and DQ8, is already used clinically to help exclude disease. However, approximately 40% of the population carry these alleles and the majority never develop CD.

OBJECTIVE

We explored whether CD risk prediction can be improved by adding non-HLA-susceptible variants to common HLA testing.

DESIGN

We developed an average weighted genetic risk score with 10, 26 and 57 single nucleotide polymorphisms (SNP) in 2675 cases and 2815 controls and assessed the improvement in risk prediction provided by the non-HLA SNP. Moreover, we assessed the transferability of the genetic risk model with 26 non-HLA variants to a nested case-control population (n=1709) and a prospective cohort (n=1245) and then tested how well this model predicted CD outcome for 985 independent individuals.

RESULTS

Adding 57 non-HLA variants to HLA testing showed a statistically significant improvement compared to scores from models based on HLA only, HLA plus 10 SNP and HLA plus 26 SNP. With 57 non-HLA variants, the area under the receiver operator characteristic curve reached 0.854 compared to 0.823 for HLA only, and 11.1% of individuals were reclassified to a more accurate risk group. We show that the risk model with HLA plus 26 SNP is useful in independent populations.

CONCLUSIONS

Predicting risk with 57 additional non-HLA variants improved the identification of potential CD patients. This demonstrates a possible role for combined HLA and non-HLA genetic testing in diagnostic work for CD.

Wheat amylase trypsin inhibitors drive intestinal inflammation via activation of toll-like receptor 4

Pest resistance molecules, α-amylase/trypsin inhibitors from wheat, activate innate immune cells through engagement of TLR4 to elicit inflammatory responses in the intestine.

Ingestion of wheat, barley, or rye triggers small intestinal inflammation in patients with celiac disease. Specifically, the storage proteins of these cereals (gluten) elicit an adaptive Th1-mediated immune response in individuals carrying HLA-DQ2 or HLA-DQ8 as major genetic predisposition. This well-defined role of adaptive immunity contrasts with an ill-defined component of innate immunity in celiac disease. We identify the α-amylase/trypsin inhibitors (ATIs) CM3 and 0.19, pest resistance molecules in wheat, as strong activators of innate immune responses in monocytes, macrophages, and dendritic cells. ATIs engage the TLR4–MD2–CD14 complex and lead to up-regulation of maturation markers and elicit release of proinflammatory cytokines in cells from celiac and nonceliac patients and in celiac patients’ biopsies. Mice deficient in TLR4 or TLR4 signaling are protected from intestinal and systemic immune responses upon oral challenge with ATIs. These findings define cereal ATIs as novel contributors to celiac disease. Moreover, ATIs may fuel inflammation and immune reactions in other intestinal and nonintestinal immune disorders.

Immunological effects of transglutaminase-treated gluten in coeliac disease

Coeliac disease pathogenesis is characterized by an immune response triggered, in genetically predisposed subjects, by ingested gluten and its withdrawal from the diet is the only available therapy. However, enzymatic modification of gluten through the insertion of lysine to avoid antigen presentation could represent a new therapeutical approach for patients. Sixty-six duodenal biopsies from 17 coeliac patients were cultured for 48 h with gluten or enzymatically-modified gluten (treated with human recombinant transglutaminase type 2 or bacterial transglutaminase, with or without lysine). Interferonγ, anti endomisium and anti transglutaminase IgA antibodies, lactate dehydrogenase and transglutaminase activity were measured in the culture medium. Transglutaminase type 2 expression was evaluated on biopsies by immunohistochemistry. Gluten and transglutaminase-treated gluten increased by 13-15 fold interferon γ release, as well as antibodies, transglutaminase activity, and the immunohistochemical expression of transglutaminase type 2. Addition of lysine to the enzymatic modification of gluten normalized interferon γ, antibodies, transglutaminase activity and immunohistochemical expression of transglutaminase type 2. Lactate dehydrogenase did not differ among the studied groups. Enzymatic modification of gluten by transglutaminase plus lysine prevents the immunologic effects on cultured duodenal biopsies from coeliac patients and could be tested as an alternative therapy in coeliac disease.

Hepcidin expression in iron overload diseases is variably modulated by circulating factors

Hepcidin is a regulatory hormone that plays a major role in controlling body iron homeostasis. Circulating factors (holotransferrin, cytokines, erythroid regulators) might variably contribute to hepcidin modulation in different pathological conditions. There are few studies analysing the relationship between hepcidin transcript and related protein expression profiles in humans. Our aims were: a. to measure hepcidin expression at either hepatic, serum and urinary level in three paradigmatic iron overload conditions (hemochromatosis, thalassemia and dysmetabolic iron overload syndrome) and in controls; b. to measure mRNA hepcidin expression in two different hepatic cell lines (HepG2 and Huh-7) exposed to patients and controls sera to assess whether circulating factors could influence hepcidin transcription in different pathological conditions. Our findings suggest that hepcidin assays reflect hepatic hepcidin production, but also indicate that correlation is not ideal, likely due to methodological limits and to several post-trascriptional events. In vitro study showed that THAL sera down-regulated, HFE-HH and C-NAFLD sera up-regulated hepcidin synthesis. HAMP mRNA expression in Huh-7 cells exposed to sera form C-Donors, HFE-HH and THAL reproduced, at lower level, the results observed in HepG2, suggesting the important but not critical role of HFE in hepcidin regulation.

Dense genotyping identifies and localizes multiple common and rare variant association signals in celiac disease

Using variants from the 1000 Genomes Project pilot European CEU dataset and data from additional resequencing studies, we densely genotyped 183 non-HLA risk loci previously associated with immune-mediated diseases in 12,041 individuals with celiac disease (cases) and 12,228 controls. We identified 13 new celiac disease risk loci reaching genome-wide significance, bringing the number of known loci (including the HLA locus) to 40. We found multiple independent association signals at over one-third of these loci, a finding that is attributable to a combination of common, low-frequency and rare genetic variants. Compared to previously available data such as those from HapMap3, our dense genotyping in a large sample collection provided a higher resolution of the pattern of linkage disequilibrium and suggested localization of many signals to finer scale regions. In particular, 29 of the 54 fine-mapped signals seemed to be localized to single genes and, in some instances, to gene regulatory elements. Altogether, we define the complex genetic architecture of the risk regions of and refine the risk signals for celiac disease, providing the next step toward uncovering the causal mechanisms of the disease.

Gene expression analysis in calcific tendinopathy of the rotator cuff

We evaluated the expression of several genes involved in tissue remodelling and bone development in patients with calcific tendinopathy of the rotator cuff. Biopsies from calcified and non-calcified areas were obtained from 10 patients (8 women and 2 men; average age: 55 years; range: 40-68) with calcific tendinopathy of the rotator cuff. To evaluate the expression of selected genes, RNA extraction, cDNA synthesis and quantitative polymerase chain reaction (PCR) were performed. A significantly increased expression of tissue transglutaminase (tTG)2 and its substrate, osteopontin, was detected in the calcific areas compared to the levels observed in the normal tissue from the same subject with calcific tendinopathy, whereas a modest increase was observed for catepsin K. There was also a significant decrease in mRNA expression of Bone Morphogenetic Protein (BMP)4 and BMP6 in the calcific area. BMP-2, collagen V and vascular endothelial growth factor (VEGF) did not show significant differences. Collagen X and matrix metalloproteinase (MMP)-9 were not detectable. A variation in expression of these genes could be characteristic of this form tendinopathy, since an increased level of these genes has not been detected in other forms of tendon lesions.

Evolutionary and functional analysis of celiac risk loci reveals SH2B3 as a protective factor against bacterial infection

Celiac disease (CD) is an intolerance to dietary proteins of wheat, barley, and rye. CD may have substantial morbidity, yet it is quite common with a prevalence of 1%-2% in Western populations. It is not clear why the CD phenotype is so prevalent despite its negative effects on human health, especially because appropriate treatment in the form of a gluten-free diet has only been available since the 1950s, when dietary gluten was discovered to be the triggering factor. The high prevalence of CD might suggest that genes underlying this disease may have been favored by the process of natural selection. We assessed signatures of selection for ten confirmed CD-associated loci in several genome-wide data sets, comprising 8154 controls from four European populations and 195 individuals from a North African population, by studying haplotype lengths via the integrated haplotype score (iHS) method. Consistent signs of positive selection for CD-associated derived alleles were observed in three loci: IL12A, IL18RAP, and SH2B3. For the SH2B3 risk allele, we also show a difference in allele frequency distribution (Fst) between HapMap phase II populations. Functional investigation of the effect of the SH2B3 genotype in response to lipopolysaccharide and muramyl dipeptide revealed that carriers of the SH2B3 rs3184504*A risk allele showed stronger activation of the NOD2 recognition pathway. This suggests that SH2B3 plays a role in protection against bacteria infection, and it provides a possible explanation for the selective sweep on SH2B3, which occurred sometime between 1200 and 1700 years ago.

Celiac disease: from pathogenesis to novel therapies

Celiac disease has become one of the best-understood HLA-linked disorders. Although it shares many immunologic features with inflammatory bowel disease, celiac disease is uniquely characterized by (1) a defined trigger (gluten proteins from wheat and related cereals), (2) the necessary presence of HLA-DQ2 or HLA-DQ8, and (3) the generation of circulating autoantibodies to the enzyme tissue transglutaminase (TG2). TG2 deamidates certain gluten peptides, increasing their affinity to HLA-DQ2 or HLA-DQ8. This generates a more vigorous CD4(+) T-helper 1 T-cell activation, which can result in intestinal mucosal inflammation, malabsorption, and numerous secondary symptoms and autoimmune diseases. Moreover, gluten elicits innate immune responses that act in concert with the adaptive immunity. Exclusion of gluten from the diet reverses many disease manifestations but is usually not or less efficient in patients with refractory celiac disease or associated autoimmune diseases. Based on the advanced understanding of the pathogenesis of celiac disease, targeted nondietary therapies have been devised, and some of these are already in phase 1 or 2 clinical trials. Examples are modified flours that have been depleted of immunogenic gluten epitopes, degradation of immunodominant gliadin peptides that resist intestinal proteases by exogenous endopeptidases, decrease of intestinal permeability by blockage of the epithelial ZOT receptor, inhibition of intestinal TG2 activity by transglutaminase inhibitors, inhibition of gluten peptide presentation by HLA-DQ2 antagonists, modulation or inhibition of proinflammatory cytokines, and induction of oral tolerance to gluten. These and other experimental therapies will be discussed critically.

Celiac disease: from pathogenesis to novel therapies

Celiac disease has become one of the best-understood HLA-linked disorders. Although it shares many immunologic features with inflammatory bowel disease, celiac disease is uniquely characterized by (1) a defined trigger (gluten proteins from wheat and related cereals), (2) the necessary presence of HLA-DQ2 or HLA-DQ8, and (3) the generation of circulating autoantibodies to the enzyme tissue transglutaminase (TG2). TG2 deamidates certain gluten peptides, increasing their affinity to HLA-DQ2 or HLA-DQ8. This generates a more vigorous CD4(+) T-helper 1 T-cell activation, which can result in intestinal mucosal inflammation, malabsorption, and numerous secondary symptoms and autoimmune diseases. Moreover, gluten elicits innate immune responses that act in concert with the adaptive immunity. Exclusion of gluten from the diet reverses many disease manifestations but is usually not or less efficient in patients with refractory celiac disease or associated autoimmune diseases. Based on the advanced understanding of the pathogenesis of celiac disease, targeted nondietary therapies have been devised, and some of these are already in phase 1 or 2 clinical trials. Examples are modified flours that have been depleted of immunogenic gluten epitopes, degradation of immunodominant gliadin peptides that resist intestinal proteases by exogenous endopeptidases, decrease of intestinal permeability by blockage of the epithelial ZOT receptor, inhibition of intestinal TG2 activity by transglutaminase inhibitors, inhibition of gluten peptide presentation by HLA-DQ2 antagonists, modulation or inhibition of proinflammatory cytokines, and induction of oral tolerance to gluten. These and other experimental therapies will be discussed critically.

Increased p21 expression in chondrocytes of achondroplasic children independently from the presence of the G380R FGFR3 mutation

BACKGROUND

Achondroplasia (ACH) represents the major cause of dwarfism and is due to mutations in the fibroblast growth factor receptor 3 (FGFR3) gene. The cellular mechanisms involved in the reduced growth have been mainly described for in vitro or in vivo models, but few data have been obtained for humans.

METHODS

Thirteen children with ACH were enrolled in the study; the presence of FGFR3 mutations was determined by restriction fragment length polymorphism analysis and sequencing, whereas protein expression in cartilage biopsy was assessed by immunohistochemistry.

RESULTS

Chondrocytes in cartilage biopsies of ACH children were characterized by the presence of growth arrest mediated by STAT activation (both STAT1 and STAT5) and increased expression of p21 and cyclin D1, whereas no expression of either p53 or cyclin D3 could be detected. This mechanism was present in ACH children carrying the G380R mutation but also in a patient in whom no mutation could be detected in the entire coding region of the FGFR3 gene.

CONCLUSIONS

These data thus demonstrate the presence of a common final mechanism involving p21 and possibly leading to a block in chondrocyte proliferation.

Analysis of HLA and non-HLA alleles can identify individuals at high risk for celiac disease

BACKGROUND & AIMS

Celiac disease (CD) is a common chronic disorder of the small intestine, resulting from aberrant cellular responses to gluten peptides, and often remains undiagnosed. It is a complex genetic disorder, although 95% of the patients carry the risk heterodimer human leukocyte antigen (HLA)-DQ2. Genome-wide association studies on CD have identified 9 non-HLA loci that also contribute to CD risk, most of which are shared with other immune-related diseases. Our aim is to predict the genetic risk for CD using HLA and non-HLA risk alleles.

METHODS

We selected 10 independent polymorphisms in 2,308 cases and 4,585 controls from Dutch, UK, and Irish populations and categorized the individuals into 3 risk groups, based on their HLA-DQ2 genotype. We used the summed number of non-HLA risk alleles per individual to analyze their cumulative effect on CD risk, adjusting for gender and population group in logistic regression analysis. We validated our findings in 436 Italian cases and 532 controls.

RESULTS

CD cases carried more non-HLA risk alleles than controls: individuals carrying > or = 13 risk alleles had a higher CD risk (odds ratio, 6.2; 95% confidence interval, 4.1-9.3) compared with those carrying 0-5 risk alleles. Combining HLA and non-HLA risk genotypes in one model increases sensitivity by 6.2% compared with using only HLA for identification of high-risk individuals with slight decrease in specificity.

CONCLUSIONS

We can use non-HLA risk factors for CD to improve identification of high-risk individuals. Our risk model is a first step toward better diagnosis and prognosis in high-risk families and population-based screening.

Coeliac disease-associated risk variants in TNFAIP3 and REL implicate altered NF-kappaB signalling

OBJECTIVE

Our previous coeliac disease genome-wide association study (GWAS) implicated risk variants in the human leucocyte antigen (HLA) region and eight novel risk regions. To identify more coeliac disease loci, we selected 458 single nucleotide polymorphisms (SNPs) that showed more modest association in the GWAS for genotyping and analysis in four independent cohorts.

DESIGN

458 SNPs were assayed in 1682 cases and 3258 controls from three populations (UK, Irish and Dutch). We combined the results with the original GWAS cohort (767 UK cases and 1422 controls); six SNPs showed association with p<1 x 10(-04) and were then genotyped in an independent Italian coeliac cohort (538 cases and 593 controls).

RESULTS

We identified two novel coeliac disease risk regions: 6q23.3 (OLIG3-TNFAIP3) and 2p16.1 (REL), both of which reached genome-wide significance in the combined analysis of all 2987 cases and 5273 controls (rs2327832 p = 1.3 x 10(-08), and rs842647 p = 5.2 x 10(-07)). We investigated the expression of these genes in the RNA isolated from biopsies and from whole blood RNA. We did not observe any changes in gene expression, nor in the correlation of genotype with gene expression.

CONCLUSIONS

Both TNFAIP3 (A20, at the protein level) and REL are key mediators in the nuclear factor kappa B (NF-kappaB) inflammatory signalling pathway. For the first time, a role for primary heritable variation in this important biological pathway predisposing to coeliac disease has been identified. Currently, the HLA risk factors and the 10 established non-HLA risk factors explain approximately 40% of the heritability of coeliac disease.

Cost-effective HLA typing with tagging SNPs predicts celiac disease risk haplotypes in the Finnish, Hungarian, and Italian populations

Human leukocyte antigen (HLA) genes, located on chromosome 6p21.3, have a crucial role in susceptibility to various autoimmune and inflammatory diseases, such as celiac disease and type 1 diabetes. Certain HLA heterodimers, namely DQ2 (encoded by the DQA1*05 and DQB1*02 alleles) and DQ8 (DQA1*03 and DQB1*0302), are necessary for the development of celiac disease. Traditional genotyping of HLA genes is laborious, time-consuming, and expensive. A novel HLA-genotyping method, using six HLA-tagging single-nucleotide polymorphisms (SNPs) and suitable for high-throughput approaches, was described recently. Our aim was to validate this method in the Finnish, Hungarian, and Italian populations. The six previously reported HLA-tagging SNPs were genotyped in patients with celiac disease and in healthy individuals from Finland, Hungary, and two distinct regions of Italy. The potential of this method was evaluated in analyzing how well the tag SNP results correlate with the HLA genotypes previously determined using traditional HLA-typing methods. Using the tagging SNP method, it is possible to determine the celiac disease risk haplotypes accurately in Finnish, Hungarian, and Italian populations, with specificity and sensitivity ranging from 95% to 100%. In addition, it predicts homozygosity and heterozygosity for a risk haplotype, allowing studies on genotypic risk effects. The method is transferable between populations and therefore suited for large-scale research studies and screening of celiac disease among high-risk individuals or at the population level.

Expression of hepcidin and other iron-related genes in type 3 hemochromatosis due to a novel mutation in transferrin receptor-2

Transferrin receptor-2 (TFR2) regulates hepatic hepcidin secretion and when mutated causes type-3 hemochromatosis. No functional study is available in humans. We studied a 47 year-old woman with hemochromatosis. TFR2 DNA and its hepatic transcript were directly sequenced. Hepatic expression of hepcidin and other iron-related genes were measured by qRT-PCR. Urinary hepcidin was measured at baseline and after an oral iron challenge (ferrous sulfate, 65 mg) by SELDI-TOF-MS. A novel homozygous TFR2 mutation was identified in the splicing donor site of intron 4 (c.614+4 A>G) causing exon 4 skipping. Hepcidin and hemojuvelin expression were markedly reduced. Urinary hepcidin was lower than normal and further decreased after iron challenge. This is the first description of iron-related gene expression profiles in a TFR2 mutated patient. The decreased hepatic and urinary expression of hepcidin and lack of acute response to iron challenge confirms the primary role of TFR2 in iron homeostasis.

TrkA pathway activation induced by amyloid-beta (Abeta)

Amyloid-beta (Abeta), a cytotoxic fragment of Amyloid Precursor Protein (APP), has been implicated in the etiopathogenesis of Alzheimer's disease (AD). Since several neurotrophins signalling pathways may be activated in response to toxic insults, we investigated whether a similar response is triggered also by Abeta. After Abeta (25-35) peptide administration to cultured rat hippocampal neurons, the nerve growth factor (NGF) and its receptor (TrkA) mRNA expression is up-regulated. Moreover, we observe an increased cellular TrkA expression (4.5 fold) and NGF release in the culture medium (5-fold). Concomitantly, TrkA, Akt and glycogen synthase kinase 3beta (Gsk3beta) phosphorylation significantly increase. Interestingly, when cells were treated with Abeta (25-35) in the presence of blocking antibody against NGF, only a partial TrkA activation (2-fold) was observed. These results have been confirmed by using pathophysiological Abeta (1-42) oligomers. Our data provide the evidence that Abeta induces the TrkA pathway activation directly by itself and indirectly promoting NGF secretion.

Six new coeliac disease loci replicated in an Italian population confirm association with coeliac disease

BACKGROUND AND AIMS

The first genome wide association study on coeliac disease (CD) and its follow-up have identified eight new loci that contribute significantly towards CD risk. Seven of these loci contain genes controlling adaptive immune responses, including IL2/IL21 (4q27), RGS1 (1q31), IL18RAP (2q11-2q12), CCR3 (3p21), IL12A (3q25-3q26), TAGAP (6q25) and SH2B3 (12q24).

METHODS

We selected the nine most associated single nucleotide polymorphisms to tag the eight new loci in an Italian cohort comprising 538 CD patients and 593 healthy controls.

RESULTS

Common variation in IL2/IL21, RGS1, IL12A/SCHIP and SH2B3 was associated with susceptibility to CD in our Italian cohort. The LPP and TAGAP regions also showed moderate association, whereas there was no association with CCR3 and IL18RAP.

CONCLUSION

This is the first replication study of six of the eight new CD loci; it is also the first CD association study in a southern European cohort. Our results may imply there is a genuine population difference across Europe regarding the loci contributing to CD.

Morphologic Overlap between Infantile Myofibromatosis and Infantile Fibrosarcoma: A Pitfall in Diagnosis

Infantile myofibromatosis (IM) is a distinctive mesenchymal disorder with different clinical forms, including solitary, multicentric, and generalized with visceral involvement. A wide morphologic spectrum is encountered, with the extremes resembling congenital infantile fibrosarcoma (CIFS) and infantile hemangiopericytoma. We report a series of lesions with mixed features of CIFS and IM and compare them in order to further define their clinicopathologic features and the significance of the so-called composite fibromatosis. Seven lesions with unusual overlapping morphologic "composite" features of both IM and CIFS were selected from a series of 106 myofibroblastic lesions. Three cases classified as composite infantile myofibromatoses (COIM) were highly cellular tumors with a diffuse growth of primitive mesenchymal cells and focal features of IM combined with areas resembling infantile fibrosarcoma (IF). Four cases were classified as IF. Three of these exhibited a biphasic pattern with foci resembling IM, including whorls of primitive and spindle cells and perivascular and intravascular projections of myofibroblastic nodules, and the 4th had a close histologic resemblance to a primitive, immature IM. With reverse transcriptase polymerase chain reaction, the ETV6-NTRK3 transcript was absent in 3 COIM and was detected in 3 CIFS; the other CIFS had typical cytogenetic aberrations. On the basis of currently available information, COIM represents a morphologic variant of IM that can mimic IF. Careful histologic evaluation to detect the typical features of IM is essential to avoid classification as IF. Molecular analysis for the ETV6-NTRK3 gene fusion is an important diagnostic tool in this group of lesions.

Hepcidin and iron-related gene expression in subjects with Dysmetabolic Hepatic Iron Overload

BACKGROUND/AIMS

Many patients with hepatic iron overload do not have identifiable mutations and often present with metabolic disorders and hepatic steatosis. Since the pathophysiology of Dysmetabolic Hepatic Iron Overload (DHIO) is still obscure, the aim of this study was to evaluate, in these patients, possible alterations in iron-related molecule expression.

METHODS

Iron-related gene mRNA levels were determined by quantitative-PCR in liver biopsies of subjects with NAFLD without iron overload and patients with HFE-hemochromatosis, beta-thalassemia major and DHIO. Urinary hepcidin was measured by immunoblotting.

RESULTS

No alterations in mRNA expression of either iron transporters or exporters were found in DHIO. mRNA and urinary hepcidin levels normalized for the amount of iron overload showed a significantly lower ratio than in controls, although not as low as in hemochromatosis or beta-thalassemia. Differently from what observed in hemochromatosis, hepcidin mRNA did not correlate with urinary hepcidin.

CONCLUSIONS

Patients with DHIO show appropriate regulation of mRNAs encoding proteins involved in iron uptake and efflux but dysregulation of hepcidin production. The relatively elevated urinary hepcidin can explain the iron phenotype in DHIO (more macrophage iron retention and low/normal transferrin saturation).

Lack of haptoglobin affects iron transport across duodenum by modulating ferroportin expression

BACKGROUND & AIMS

Haptoglobin is an acute phase protein responsible for the recovery of free hemoglobin from plasma. Haptoglobin-null mice were previously shown to have an altered heme-iron distribution, thus reproducing what occurs in humans in cases of congenital or acquired anhaptoglobinemia. Here, we report the analysis of iron homeostasis in haptoglobin-null mice.

METHODS

Iron absorption was measured in tied-off duodenal segments. Iron stores were evaluated on tissue homogenates and sections. The expression of molecules involved in iron homeostasis was analyzed at the protein and messenger RNA levels both in mice and in murine RAW264.7 macrophages stimulated in vitro with hemoglobin.

RESULTS

Analysis of intestinal iron transport reveals that haptoglobin-null mice export significantly more iron from the duodenal mucosa to plasma compared with control counterparts. Increased iron export from the duodenum correlates with increased duodenal expression of ferroportin, both at the protein and messenger RNA levels, whereas hepatic hepcidin expression remains unchanged. Up-regulation of the ferroportin transcript, but not of the protein, also occurs in haptoglobin-null spleen macrophages, which accumulate free hemoglobin-derived iron. Finally, we demonstrate that hemoglobin induces ferroportin expression in RAW264.7 cells.

CONCLUSIONS

Taking together these data, we suggest that haptoglobin, by controlling plasma levels of hemoglobin, participates in the regulation of ferroportin expression, thus contributing to the regulation of iron transfer from duodenal mucosa to plasma.

CD34 human hematopoietic progenitor cell line, MUTZ-3, differentiates into functional osteoclasts

OBJECTIVE

CD14(+) monocyte cell lines can differentiate into an osteoclast (OC)-like lineage. However, the identification of human cell lines with stem cell characteristics, capable of differentiating into OCs, would provide a tool for the study of the molecular mechanisms regulating their commitment, differentiation, and function. Since the human acute myeloid leukemia cell line MUTZ-3 contains both CD34(+) stem cell and CD14(+) cell populations, we investigated the capacity of the stem/progenitor CD34(+) population to differentiate into functional OCs.

MATERIALS AND METHODS

Sorted MUTZ-3-CD34(+) and MUTZ-3-CD14(+) cells were cultured in presence of M-CSF, RANK-L, and TNF-alpha to generate OCs. Differentiation was evaluated by TRAP staining and RT-PCR, which assessed the expression of c-fms, RANK, MMP-9, CATK, TRAP, and CTR in -CD34(+)OC and -CD14(+)OC cells. Resorption pit formation was also evaluated. CD34, CD14, M-CSF-R, RANK, and CTR expression was assessed by FACS analysis.

RESULTS

MUTZ-3-CD34(+) differentiated into OCs, displaying the full range of differentiation markers; MMP-9, CATK, TRAP, and RANK mRNA were detected from day 3 of culture, whereas CTR from day 12. Stimulated MUTZ-3-CD34(+) generated functional osteoclasts that formed extensive resorption lacunae on both mineralized surface and bone slices. Surprisingly, in both sorted populations we identified a population M-CSF-R(+)/RANK(+) that at the same time co-expressed CD14 and CD34.

CONCLUSIONS

These findings demonstrate that MUTZ-3 cells constitute an invaluable model to study the expression pattern in different developmental stages of commitment and differentiation. Importantly, the data indicate that the CD14(+)CD34(+)M-CSF-R(+)RANK(+) population represents an intermediate stage of differentiation from CD34 precursors and monocytes to osteoclast.

Endometrioid-like yolk sac and Sertoli-Leydig cell tumors in a carrier of a Y heterochromatin insertion into 1qh region: a causal association?

We describe the case of a young woman showing yolk sac tumors (YST) and a Sertoli-Leydig cell tumor (SLCT) in the right ovary, with recurrences in the right adnexum and with hepatic metastasis. To our knowledge, YST and SLCT have never been described as components of the same tumor or reported as associated in the same patient. The patient's karyotype showed the presence of Y chromosome inserted into the 1qh region; the inserted region corresponded to Yq12 heterochromatin. LOH analysis revealed 1p36 paternal allele loss in the proband tumor, thus supporting a germ cell origin for the tumor. The presence of Y heterochromatin in 1qh DNA might induce disturbances in the normal regulation of oncogenes located in 1q.

IL-10 polymorphisms are associated with early-onset celiac disease and severe mucosal damage in patients of Caucasian origin

PURPOSE

Polymorphisms in cytokine genes can determine their level of expression and affect the phenotypic expression of immunomediated diseases, such as celiac disease (CD). We thus evaluated cytokine polymorphism prevalence in CD patients and population controls, and assessed the correlation between specific polymorphisms and celiacs' clinical characteristics.

METHODS

155 CD patients and 202 population controls were enrolled in the study. Cytokine polymorphisms (TNFalpha -308 and -238, IL-1beta -511 and +3954, IL-1b RN + 2018, IL-6 -174, IL-10 -1082, -819 and -592, TGFbeta1 + 29 and +74, IFN-gamma + 874) and HLA class II alleles were determined by sequence-specific primer polymerase chain reaction or restriction fragment length polymorphism analysis. Duodenal histology was classified using Marsh's criteria. Variables significantly associated with CD patients' characteristics were identified by multivariate logistic regression analysis.

RESULTS

A significantly higher frequency of -308 TNFalpha polymorphism was observed in CD patients compared to the entire population control group, although no difference was detected when population controls were stratified according to HLA class II. Among celiacs, early onset of the disease (< or =2 year old) and the presence of a severe intestinal lesion (Marsh 3C) were significantly associated with the -1082 A/A IL-10 genotype which corresponds to a low producer phenotype (OR 3.28, 95% CI 1.49-7.19 and OR 2.60, 95% CI 1.04-6.49, respectively).

CONCLUSION

The association between IL-10 genotypes and both histological severity at diagnosis and age of onset could be related to an alteration in cytokine balance, and supports the idea that the various clinical manifestations of the disease could be determined by a different genetic background.

Usefulness of the organ culture system in the in vitro diagnosis of coeliac disease: a multicentre study

OBJECTIVE

Diagnosis of coeliac disease is based on the presence of villous atrophy which recovers following a gluten-free diet. The presence of circulating antiendomysial antibodies as well as their disappearance after a gluten-free diet supports the diagnosis. It has also been demonstrated that antiendomysial antibodies are detectable in supernatants of cultured intestinal biopsies from patients with coeliac disease. The objective of this study was to compare the histology and antiendomysial antibodies in culture supernatants of intestinal biopsies to validate the in vitro organ culture system as a future diagnostic tool for coeliac disease.

MATERIAL AND METHODS

Seventy-five antiendomysial serum-positive patients on a gluten-containing diet were evaluated. Patients underwent endoscopy with 5 biopsy fragments: 3 for histology, 1 cultured with and the other without gliadin-peptide activator. Antiendomysial antibodies were evaluated in all culture supernatants.

RESULTS

Sixty-eight patients had evidence of villous atrophy, while 73 out of 75 were positive to the organ culture system. The agreement rate between organ culture and histology results was 94%.

CONCLUSIONS

As all the centres participating in the study obtained good agreement between organ culture and histology results, the new system could be considered a reliable tool for the diagnosis of coeliac disease. Nevertheless, it is possible to highlight cases with an organ culture-positive and -negative histology. This feature could be of considerable interest because, as the sensitivity of organ culture seems to be greater than the initial histology, the new system might be useful in uncertain cases where the risk of missing the diagnosis of coeliac disease is high.

Hemochromatosis gene mutations and iron metabolism in celiac disease

BACKGROUND AND OBJECTIVES

Iron deficiency anemia is a common manifestation of celiac disease, which may be due to genetic and environmental factors. HFE mutations, frequent in Caucasian populations, can cause increased intestinal iron absorption and thus could protect against the development of iron deficiency. The aim of this study was to evaluate the prevalence of HFE mutations and their effect on iron metabolism in Italian celiac patients at diagnosis and after a gluten-free diet.

DESIGN AND METHODS

C282Y and H63D mutations were assessed by polymerase chain reaction (PCR) and restriction enzyme digestion in 203 patients with celiac disease and in 206 controls. HLA alleles were determined by sequence-specific primers and PCR. Duodenal histology was graded using Marsh's classification, and iron parameters measured by standard techniques.

RESULTS

The frequency of the C282Y mutation was similar in celiac patients and controls (0.034 vs. 0.031); comparable frequencies were detected also for the H63D allele (0.170 vs. 0.136 in celiac patients and controls, respectively). Neither of the two HFE mutations affected iron indices in celiac patients at diagnosis, whereas a significant inverse correlation was detected between hemoglobin or ferritin and severity of histological damage (Marsh 3C or 3B vs. 3A, p<0.05 for both parameters). After a gluten-free diet, a slight increase in hemoglobin levels was observed in C282Y carriers as compared to controls, but only in female patients (p=0.044).

INTERPRETATION AND CONCLUSIONS

In Italian patients with untreated celiac disease, HFE mutations do not constitute a protective factor against the development of iron deficiency, which seems to be mainly determined by the severity of the intestinal lesions.

Adaptive changes of duodenal iron transport proteins in celiac disease

Iron deficiency is a manifestation of celiac disease (CD) usually attributed to a decreased absorptive surface, although no data on the regulation of iron transport under these conditions are currently available. Our aim was to evaluate divalent metal transporter 1 (DMT1), duodenal cytochrome b (Dcytb), ferroportin 1 (FP1), hephaestin, and transferrin receptor 1 (TfR1) expression, as well as iron regulatory protein (IRP) activity in duodenal biopsies from control, anemic, and CD patients. We studied 10 subjects with dyspepsia, 6 with iron-deficiency anemia, and 25 with CD. mRNA levels were determined by real-time PCR, protein expression by Western blotting or immunohistochemistry, and IRP activity by gel shift assay. Our results showed that DMT1, FP1, hephaestin, and TfR1 mRNA levels were significantly increased in CD patients with reduced body iron stores compared with controls, similar to what was observed in anemic patients. Protein expression paralleled the mRNAs changes. DMT1 protein expression was localized in differentiated enterocytes at the villi tips in controls, whereas with iron deficiency it was observed throughout the villi. FP1 expression was localized on the basolateral membrane of enterocytes and increased with low iron stores. TfR1 was localized in the crypts in controls but also in the villi with iron deficiency. These changes were paralleled by IRP activity, which increased in all iron-deficient subjects. We conclude that duodenal DMT1, FP1, hephaestin, and TfR1 expression and IRP activity, thus the iron absorption capacity, are upregulated in CD patients as a consequence of iron deficiency, whereas the increased enterocyte proliferation observed in CD has no effect on iron uptake regulation.

Genomic organization and transcription of the human retinol dehydrogenase 10 (RDH10) gene

A cDNA clone up-regulated in hydraulic lung edema in rabbit showed high similarity with human RDH10 mRNA, which encodes a protein involved in retinoic acid metabolism. We defined the organization of the human gene, which includes a unique transcriptional start site, a coding region with six translated exons and a 3' untranslated region containing at least two used polyadenylation sites. The two poly(A) signals are responsible for the production of the 3 and 4 kb RDH10 mRNA isoforms detected in several human tissues and cell lines.

A new human cell line, PDSS-26, from poorly differentiated synovial sarcoma, with unique chromosomal anomalies

Permanent synovial sarcoma cell lines are invaluable tools for understanding of the biology of this tumor. The present study reports the establishment of a new human cell line, PDSS-26, derived from a surgical specimen of a poorly differentiated synovial sarcoma. PDSS-26 has a doubling time of a 72 hours and grows as a monolayer of spindle cells that retain immunoreactivity for bcl-2 and vimentin. Karyotypic analysis revealed a rearrangement involving chromosomes 17 and 18, at the breakpoints q11.2 and q11.2, respectively, as the only structural aberrations. Analysis by reverse transcriptase polymerase chain reaction showed the presence of the SYT-SSX1 fusion transcript in both the primary tumor and the cell line. Cytoplasmic PTEN staining was detected by immunohistochemistry in both the PDSS-26 cell line and in original tumor, whereas no mutation was identified by automatic sequencing. Thus, PDSS-26 cells could be useful for future functional studies.

Gene expression analysis in interstitial lung edema induced by saline infusion

To investigate the molecular events taking place during the development of hydraulic interstitial edema, we analyzed by microarray and conventional molecular techniques the variation of gene expression in lung from rabbits treated with slow-rate saline infusions. This analysis indicates that even a condition characterized by a small increase in extravascular water can have a significant influence on the inflammatory milieu. In this regard, cytokines, in particular TNFalpha, can be considered early mediators capable of inducing secondary effects on the injured tissue. Moreover, two MT1 genes were strongly up-regulated, data consistent with their role as protective molecules.