Nontypeable Haemophilus influenzae induces COX-2 and PGE2 expression in lung epithelial cells via activation of p38 MAPK and NF-kappa B

<p>Abstract</p> <p>Background</p> <p>Nontypeable <it>Haemophilus influenzae </it>(NTHi) is an important respiratory pathogen implicated as an infectious trigger in chronic obstructive pulmonary disease, but its molecular interaction with human lung epithelial cells remains unclear. Herein, we tested that the hypothesis that NTHi induces the expression of cyclooxygenase (COX)-2 and prostaglandin E2 (PGE2) via activation of p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-kappa B in pulmonary alveolar epithelial cells.</p> <p>Methods</p> <p>Human alveolar epithelial A549 cells were infected with different concentrations of NTHi. The phosphorylation of p38 MAPK was detected by Western blot analysis, the DNA binding activity of NF-kappa B was assessed by electrophoretic mobility shift assay (EMSA), and the expressions of COX-1 and 2 mRNA and PGE2 protein were measured by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme linked immunosorbent assay (ELISA), respectively. The roles of Toll-like receptor (TLR) 2 and TLR4, well known NTHi recognizing receptor in lung epithelial cell and gram-negative bacteria receptor, respectively, on the NTHi-induced COX-2 expression were investigated in the HEK293 cells overexpressing TLR2 and TLR4 <it>in vitro </it>and in the mouse model of NTHi-induced pneumonia by using TLR2 and TLR4 knock-out mice <it>in vivo</it>. In addition, the role of p38 MAPK and NF-kappa B on the NTHi-induced COX-2 and PGE2 expression was investigated by using their specific chemical inhibitors.</p> <p>Results</p> <p>NTHi induced COX-2 mRNA expression in a dose-dependent manner, but not COX-1 mRNA expression in A549 cells. The enhanced expression of PGE2 by NTHi infection was significantly decreased by pre-treatment of COX-2 specific inhibitor, but not by COX-1 inhibitor. NTHi induced COX-2 expression was mediated by TLR2 in the epithelial cell <it>in vitro </it>and in the lungs of mice <it>in vivo</it>. NTHi induced phosphorylation of p38 MAPK and up-regulated DNA binding activity of NF-kappa B. Moreover, the expressions of COX-2 and PGE2 were significantly inhibited by specific inhibitors of p38 MAPK and NF-kappa B. However, NTHi-induced DNA binding activity of NF-kappa B was not affected by the inhibition of p38 MAPK.</p> <p>Conclusion</p> <p>NTHi induces COX-2 and PGE2 expression in a p38 MAPK and NF-kappa B-dependent manner through TLR2 in lung epithelial cells <it>in vitro </it>and lung tissues <it>in vivo</it>. The full understanding of the role of endogenous anti-inflammatory PGE2 and its regulation will bring new insight to the resolution of inflammation in pulmonary bacterial infections.</p

Hemagglutinin from the H5N1 Virus Activates Janus Kinase 3 to Dysregulate Innate Immunity

Highly pathogenic avian influenza viruses (HPAIVs) cause severe disease in humans. There are no effective vaccines or antiviral therapies currently available to control fatal outbreaks due in part to the lack of understanding of virus-mediated immunopathology. In our study, we used hemagglutinin (HA) of H5N1 virus to investigate the related signaling pathways and their relationship to dysregulated innate immune reaction. We found the HA of H5N1 avian influenza triggered an abnormal innate immune signalling in the pulmonary epithelial cells, through an unusual process involving activation of Janus kinase 3 (JAK3) that is exclusively associated with γc chain and is essential for signaling via all γc cytokine receptors. By using a selective JAK3 inhibitor and JAK3 knockout mice, we have, for the first time, demonstrated the ability to target active JAK3 to counteract injury to the lungs and protect immunocytes from acute hypercytokinemia -induced destruction following the challenge of H5N1 HA in vitro and in vivo. On the basis of the present data, it appears that the efficacy of selective JAK3 inhibition is likely based on its ability to block multiple cytokines and protect against a superinflammatory response to pathogen-associated molecular patterns (PAMPs) attack. Our findings highlight the potential value of selective JAK3 inhibitor in treating the fatal immunopathology caused by H5N1 challenge

Effect of Hookworm Infection on Wheat Challenge in Celiac Disease – A Randomised Double-Blinded Placebo Controlled Trial

Background and Aims: The association between hygiene and prevalence of autoimmune disease has been attributed in part to enteric helminth infection. A pilot study of experimental infection with the hookworm Necator americanus was undertaken among a group of otherwise healthy people with celiac disease to test the potential of the helminth to suppress the immunopathology induced by gluten

A Universal Approach to Eliminate Antigenic Properties of Alpha-Gliadin Peptides in Celiac Disease

Celiac disease is caused by an uncontrolled immune response to gluten, a heterogeneous mixture of wheat storage proteins, including the α-gliadins. It has been shown that α-gliadins harbor several major epitopes involved in the disease pathogenesis. A major step towards elimination of gluten toxicity for celiac disease patients would thus be the elimination of such epitopes from α-gliadins. We have analyzed over 3,000 expressed α-gliadin sequences from 11 bread wheat cultivars to determine whether they encode for peptides potentially involved in celiac disease. All identified epitope variants were synthesized as peptides and tested for binding to the disease-associated HLA-DQ2 and HLA-DQ8 molecules and for recognition by patient-derived α-gliadin specific T cell clones. Several specific naturally occurring amino acid substitutions were identified for each of the α-gliadin derived peptides involved in celiac disease that eliminate the antigenic properties of the epitope variants. Finally, we provide proof of principle at the peptide level that through the systematic introduction of such naturally occurring variations α-gliadins genes can be generated that no longer encode antigenic peptides. This forms a crucial step in the development of strategies to modify gluten genes in wheat so that it becomes safe for celiac disease patients. It also provides the information to design and introduce safe gluten genes in other cereals, which would exhibit improved quality while remaining safe for consumption by celiac disease patients

Influence of Milk-Feeding Type and Genetic Risk of Developing Coeliac Disease on Intestinal Microbiota of Infants: The PROFICEL Study

Interactions between environmental factors and predisposing genes could be involved in the development of coeliac disease (CD). This study has assessed whether milk-feeding type and HLA-genotype influence the intestinal microbiota composition of infants with a family history of CD. The study included 164 healthy newborns, with at least one first-degree relative with CD, classified according to their HLA-DQ genotype by PCR-SSP DQB1 and DQA1 typing. Faecal microbiota was analysed by quantitative PCR at 7 days, and at 1 and 4 months of age. Significant interactions between milk-feeding type and HLA-DQ genotype on bacterial numbers were not detected by applying a linear mixed-model analysis for repeated measures. In the whole population, breast-feeding promoted colonization of C. leptum group, B. longum and B. breve, while formula-feeding promoted that of Bacteroides fragilis group, C. coccoides-E. rectale group, E. coli and B. lactis. Moreover, increased numbers of B. fragilis group and Staphylococcus spp., and reduced numbers of Bifidobacterium spp. and B. longum were detected in infants with increased genetic risk of developing CD. Analyses within subgroups of either breast-fed or formula-fed infants indicated that in both cases increased risk of CD was associated with lower numbers of B. longum and/or Bifidobacterium spp. In addition, in breast-fed infants the increased genetic risk of developing CD was associated with increased C. leptum group numbers, while in formula-fed infants it was associated with increased Staphylococcus and B. fragilis group numbers. Overall, milk-feeding type in conjunction with HLA-DQ genotype play a role in establishing infants' gut microbiota; moreover, breast-feeding reduced the genotype-related differences in microbiota composition, which could partly explain the protective role attributed to breast milk in this disorder

Spectrum of gluten-related disorders: consensus on new nomenclature and classification

A decade ago celiac disease was considered extremely rare outside Europe and, therefore, was almost completely ignored by health care professionals. In only 10 years, key milestones have moved celiac disease from obscurity into the popular spotlight worldwide. Now we are observing another interesting phenomenon that is generating great confusion among health care professionals. The number of individuals embracing a gluten-free diet (GFD) appears much higher than the projected number of celiac disease patients, fueling a global market of gluten-free products approaching $2.5 billion (US) in global sales in 2010. This trend is supported by the notion that, along with celiac disease, other conditions related to the ingestion of gluten have emerged as health care concerns. This review will summarize our current knowledge about the three main forms of gluten reactions: allergic (wheat allergy), autoimmune (celiac disease, dermatitis herpetiformis and gluten ataxia) and possibly immune-mediated (gluten sensitivity), and also outline pathogenic, clinical and epidemiological differences and propose new nomenclature and classifications

CD28null CD4 T-cell expansions in autoimmune disease suggest a link with cytomegalovirus infection

Immunosenescence is thought to contribute to the increase of autoimmune diseases in older people. Immunosenescence is often associated with the presence of an expanded population of CD4 T cells lacking expression of CD28 (CD28null). These highly cytotoxic CD4 T cells were isolated from disease-affected tissues in patients with rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, or other chronic inflammatory diseases and their numbers appeared to be linked to disease severity. However, we recently demonstrated that the common herpes virus, cytomegalovirus (CMV), not ageing, is the major driver of this subset of cytotoxic T cells. In this review, we discuss how CMV might potentiate and exacerbate autoimmune disease through the expansion of CD28null CD4 T cells

Mitochondrial Diabetes in Children: Seek and You Will Find It

Maternally Inherited Diabetes and Deafness (MIDD) is a rare form of diabetes due to defects in mitochondrial DNA (mtDNA). 3243 A>G is the mutation most frequently associated with this condition, but other mtDNA variants have been linked with a diabetic phenotype suggestive of MIDD. From 1989 to 2009, we clinically diagnosed mitochondrial diabetes in 11 diabetic children. Diagnosis was based on the presence of one or more of the following criteria: 1) maculopathy; 2) hearing impairment; 3) maternal heritability of diabetes/impaired fasting glucose and/or hearing impairment and/or maculopathy in three consecutive generations (or in two generations if 2 or 3 members of a family were affected). We sequenced the mtDNA in the 11 probands, in their mothers and in 80 controls. We identified 33 diabetes-suspected mutations, 1/33 was 3243A>G. Most patients (91%) and their mothers had mutations in complex I and/or IV of the respiratory chain. We measured the activity of these two enzymes and found that they were less active in mutated patients and their mothers than in the healthy control pool. The prevalence of hearing loss (36% vs 75–98%) and macular dystrophy (54% vs 86%) was lower in our mitochondrial diabetic adolescents than reported in adults. Moreover, we found a hitherto unknown association between mitochondrial diabetes and celiac disease. In conclusion, mitochondrial diabetes should be considered a complex syndrome with several phenotypic variants. Moreover, deafness is not an essential component of the disease in children. The whole mtDNA should be screened because the 3243A>G variant is not as frequent in children as in adults. In fact, 91% of our patients were mutated in the complex I and/or IV genes. The enzymatic assay may be a useful tool with which to confirm the pathogenic significance of detected variants