Lipopolysaccharide-induced down-regulation of uteroglobin in the human nose

[Th2 cells and macrophages induce novel type-I-hypersensitivity-like reaction]

In recent decades, many patients have been suffering from allergic rhinitis including Japanese cedar pollinosis, which is becoming a national disease in Japan. There is other upper airway intractable disease, called eosinophilic sinusitis. The elucidation of the pathogenesis of upper airway intractable disease is demanded for the development of novel therapies. Many researches about allergic pathogenesis have focused on IgE-mast cells pathway, however, there are the patients with allergic symptoms induced by non-IgE mediated mechanisms. The patients who show allergic rhinitis-like symptoms, such as sneezing, nasal discharge, and nasal clotting, without allergen-specific IgE, are diagnosed as non-allergic rhinitis. The precise mechanisms of non-allergic rhinitis are totally unclear. We have investigated the non-IgE mediated nasal symptoms, because the elucidation of non-IgE mediated mechanisms might lead to the elucidation of other upper airway intractable disease. We established antigen-specific Th2 cells transfer model and revealed the novel allergic mechanisms induced by Th2 cells, macrophages and endotoxin. Although Th2 cells play important roles in allergic diseases, the main function of Th2 cells are thought to produce Th2 cytokines, such as interleukin (IL)-4, IL-5, IL-13. We revealed the new functions of Th2 cells in allergic diseases. In addition, we found the novel histamine production mechanisms using in vitro macrophages and Th2 cells co-culture model. Both macrophages and Th2 cells produced histamine by the interaction through antigen. Our observations suggested the existence of the novel allergic mechanisms distinct from IgE-mast cells pathway.

Nasal Lipopolysaccharide Challenge and Cytokine Measurement Reflects Innate Mucosal Immune Responsiveness

Background

Practical methods of monitoring innate immune mucosal responsiveness are lacking. Lipopolysaccharide (LPS) is a component of the cell wall of Gram negative bacteria and a potent activator of Toll-like receptor (TLR)-4. To measure LPS responsiveness of the nasal mucosa, we administered LPS as a nasal spray and quantified chemokine and cytokine levels in mucosal lining fluid (MLF).

Methods

We performed a 5-way cross-over, single blind, placebo-controlled study in 15 healthy non-atopic subjects (n = 14 per protocol). Doses of ultrapure LPS (1, 10, 30 or 100μg/100μl) or placebo were administered by a single nasal spray to each nostril. Using the recently developed method of nasosorption with synthetic adsorptive matrices (SAM), a series of samples were taken. A panel of seven cytokines/chemokines were measured by multiplex immunoassay in MLF. mRNA for intercellular cell adhesion molecule-1 (ICAM-1) was quantified from nasal epithelial curettage samples taken before and after challenge.

Results

Topical nasal LPS was well tolerated, causing no symptoms and no visible changes to the nasal mucosa. LPS induced dose-related increases in MLF levels of IL-1β, IL-6, CXCL8 (IL-8) and CCL3 (MIP-1α) (AUC at 0.5 to 10h, compared to placebo, p<0.05 at 30 and 100μg LPS). At 100μg LPS, IL-10, IFN-α and TNF-α were also increased (p<0.05). Dose-related changes in mucosal ICAM-1 mRNA were also seen after challenge, and neutrophils appeared to peak in MLF at 8h. However, 2 subjects with high baseline cytokine levels showed prominent cytokine and chemokine responses to relatively low LPS doses (10μg and 30μg LPS).

Conclusions

Topical nasal LPS causes dose-dependent increases in cytokines, chemokines, mRNA and cells. However, responsiveness can show unpredictable variations, possibly because baseline innate tone is affected by environmental factors. We believe that this new technique will have wide application in the study of the innate immune responses of the respiratory mucosa.

Key Messages

Ultrapure LPS was used as innate immune stimulus in a human nasal challenge model, with serial sampling of nasal mucosal lining fluid (MLF) by nasosorption using a synthetic absorptive matrix (SAM), and nasal curettage of mucosal cells. A dose response could be demonstrated in terms of levels of IL-1β, IL-6, CXCL8 and CCL3 in MLF, as well as ICAM-1 mRNA in nasal curettage specimens, and levels of neutrophils in nasal lavage. Depending on higher baseline levels of inflammation, there were occasional magnified innate inflammatory responses to LPS.

Trial Registration

Clinical Trials.gov NCT02284074

Oxidative & nitrosative stress in depression: why so much stress?

Many studies support a crucial role for oxidative & nitrosative stress (O&NS) in the pathophysiology of unipolar and bipolar depression. These disorders are characterized inter alia by lowered antioxidant defenses, including: lower levels of zinc, coenzyme Q10, vitamin E and glutathione; increased lipid peroxidation; damage to proteins, DNA and mitochondria; secondary autoimmune responses directed against redox modified nitrosylated proteins and oxidative specific epitopes. This review examines and details a model through which a complex series of environmental factors and biological pathways contribute to increased redox signaling and consequently increased O&NS in mood disorders. This multi-step process highlights the potential for future interventions that encompass a diverse range of environmental and molecular targets in the treatment of depression.

Club cell 10-kDa protein attenuates airway mucus hypersecretion and inflammation

Bacterial lipopolysaccharide (LPS) and interleukin (IL)-13 increase mucus secretion and inflammatory cytokine production in normal human bronchial epithelial (NHBE) cells. We evaluated the effect of club cell 10-kDa protein (CC10), an anti-inflammatory protein produced by epithelial cells, on mucus secretion, cell morphology and inflammatory cytokine production.

NHBE cells were cultured at an air–liquid interface with CC10 or vehicle and exposed to LPS on day 14. Mucin MUC5AC, IL-8 and granulocyte-macrophage colony-stimulating factor were measured in cell supernatants. MUC5AC and IL-8 mRNA expression were measured by real-time PCR. Western blotting was used to evaluate nuclear factor (NF)-κB and extracellular signal-regulated kinase (ERK) activation. Cells were evaluated histologically. Additionally, NHBE cells were exposed to IL-13 and CC10 for 14 days, and secretion of the mucins MUC5AC and MUC5B was measured.

MUC5AC secretion stimulated either by LPS or by IL-13 was attenuated by CC10 at 20 ng·mL−1 (p<0.05). CC10 at 20 ng·mL−1 also attenuated IL-8 secretion (p<0.05). MUC5AC and IL-8 mRNA expression were also decreased by CC10 (p<0.05). CC10 attenuated phosphorylation of NF-κB (p<0.05) and ERK1/2 (p<0.05).

CC10 attenuates LPS-induced mucus secretion in airway cells, in part due to inhibition of NF-κB and ERK phosphorylation.

Systemic up-regulation of TLR4 causes lipopolysaccharide-induced augmentation of nasal cytokine release in allergic rhinitis

BACKGROUND

Allergic rhinitis is a systemic disorder, and it is clinically well recognized that it can be aggravated by infection. Activation of the innate immune system constitutes a critical element in the process. Toll-like receptors (TLRs) comprise a part of the innate immune system, and lipopolysaccharide (LPS)-induced activation of TLR4 represents bacterial-induced interactions in various model systems. The present study examines how TLR2 and TLR4 expression is affected by symptomatic allergic rhinitis, and if LPS added upon allergen affects nasal cytokine release.

METHODS

In patients with pollen-induced allergic rhinitis and healthy non-allergic volunteers, nasal lavage (NAL), peripheral blood and bone marrow were sampled before and during the pollen season. TLR2 and TLR4 expression was determined flow cytometrically. Changes in the TLR receptor expression pattern were evaluated by a nasal challenge with allergen followed by LPS, or vice versa. Symptoms along with cells and cytokines in NAL were analyzed.

RESULTS

TLR4 expression increased in leukocytes in NAL, peripheral blood and bone marrow during symptomatic allergic rhinitis. A similar increase was seen for TLR2 in neutrophils in blood. Nasal challenge with allergen followed by LPS augmented the release of IL-4, IL-5, IL-10, IL-13, IFN-γ and TNF-α.

CONCLUSION

A systemic up-regulation of TLR4 in symptomatic allergic rhinitis may explain why LPS preceded by allergen increases nasal cytokine release.

Experimentally induced eosinophilic polyps in rabbit sinuses

BACKGROUND

Nasal polyps are one of the most common findings of physical examination in the otolaryngology area and the experimental model of nasal polyps in the rabbit maxillary sinus is helpful for clarifying the mechanism of polyp formation. Several protocols have been reported for this model, but most of them involved infectious polyps without eosinophil infiltration. We have attempted to establish a novel rabbit model of polyps associated with eosinophil infiltration.

METHODS

Rabbits were either untreated (group A) or sensitized with ovalbumin (OVA; groups B-D). After repeated exposure to OVA, some animals further received valine-glycine-serine-glutamine (group C) or poly-L-arginine (group D) in their maxillary sinuses for 4 weeks. Subsequently, sinus tissues were dissected and subjected to histological analysis. The changes in mRNA expression were analyzed by DNA microarray.

RESULTS

Remarkable histological changes were observed in groups C and D but not in group B in eosinophil number in the maxillary sinus mucosa, the width of the lamina propria, and polyp scoring. These changes in group D were greater than those in group C. DNA microarray analysis revealed that up-regulated genes in group D included those related to inflammation and extracellular matrix metabolism. On the other hand, down-regulated genes in group D involved those related to anti-inflammation.

CONCLUSION

Our results indicate that treatment with inflammatory agents, in combination with an antigen-dependent immune response, could induce nasal polyp formation associated with eosinophil infiltration and mucosal hypertrophy. The gene expression profile supported the clinical relevance of this model.

Nod1, Nod2 and Nalp3 receptors, new potential targets in treatment of allergic rhinitis?

BACKGROUND

Recently, a new set of pattern-recognition receptors, the nucleotide-binding oligomerization domain (Nod)-like receptors (NLRs), have emerged. Their activation, either by allergens or microbes, triggers an inflammatory response. The knowledge about NLRs in human airways is limited.

AIM OF THE STUDY

To investigate presence of NLRs in the human nose of healthy individuals and patients with intermittent allergic rhinitis outside and during pollen season.

METHODS

The expression of Nod1, Nod2, and Nalp3 in nasal biopsies was determined with real-time RT-PCR and immunohistochemistry. Cultured primary human nasal epithelial cells (HNECs) were analyzed using real-time RT-PCR and flow cytometry to further verify the presence of NLRs in the epithelium.

RESULTS

Immunohistochemical analysis revealed presence of Nod1, Nod2, and Nalp3 in the nasal epithelium. This was corroborated in cultured HNECs. Patients suffering from symptomatic allergic rhinitis exhibited lower Nod1 and Nalp3 mRNA levels than both controls and patients during pollen season. Nod2 expression was found in all specimens tested, but no differences were seen between the three groups.

CONCLUSION

Nod1, Nod2, and Nalp3 receptors were found to be present in the human nose. The expression of Nod1 and Nalp3 were down-regulated during pollen season among patients with allergic rhinitis. This opens up for new insights and novel therapeutic strategies in inflammatory airway disease.

A decade of improvements in quantification of gene expression and internal standard selection

Major improvements have been made in mRNA quantification and internal standard selection over the last decade. Our aim in this paper is to present the main developments that are of interest for practical laboratory work, contrasting the situation as it is now with the one of ten years ago, and presenting some excellent examples of what can be done today. Specifically, we will mainly discuss Real-Time RT-PCR major improvements that have been performed in the following areas: the most commonly used quantification techniques, the mathematical and software tools created to help researchers in their work on internal standard selection, the availability of detection chemistries and technical information and of commercial tools and services. In addition to mRNA quantification, we will also discuss some aspects of non-coding RNA and protein quantification. In addition to technical improvements, the development of international cooperation and the creation of technical databases are likely to represent a major tool for the future in the standardization of gene expression quantification.

Lipopolysaccharide administration to the allergic nose contributes to lower airway inflammation

BACKGROUND

Allergic rhinitis (AR) is an inflammatory reaction not confined to a single local compartment, but rather involving the whole airway system. Allergens known to induce AR are not always the sole trigger of the inflammatory reaction as infections and organic dust might also cause exacerbations of rhinitis and associated conditions.

OBJECTIVE

To examine the effects of intranasal lipopolysaccharide (LPS) exposure, as a surrogate for upper airway bacterial infections, in patients with symptomatic AR.

METHODS

Fourteen patients with a history of moderate to severe pollen-induced AR were challenged intranasally with LPS. After 3-6 weeks, the same patients were challenged again, first with allergen and 24 h later with LPS. Nasal symptom scores, nasal lavage leucocyte counts and nasal airway resistance were assessed at 6-24 h after each provocation along with measurements of nitric oxide (NO) levels in the nose and lung.

RESULTS

Six hours after the LPS challenge, an increased level of leucocytes could be obtained in the lavage fluid, but no symptoms were experienced and no increase in nasal resistance could be recorded. The NO production in the upper and lower airways was similar before and 6 h after the provocation. In contrast, in patients exposed to pollen before the LPS challenge, both the nasal and the pulmonary NO levels were enhanced. This was accompanied by an increase in leucocytes.

CONCLUSION

The present study demonstrates a priming effect of allergen on the nasal response to LPS as well as the presence of a systemic link between airway mucosal sites in the upper and lower airways. This suggests that exogenously derived signals, like upper airway infections, can interfere with the initiation, maintenance and progression of asthma.