Effect of brimonidine tartrate on basophil activation in glaucoma patients.

AIM: To evaluate the mechanism of which brimonidine tartrate 0.15% causes clinical hypersensitivity. METHODS: A prospective case-control study comparing 8 glaucoma patients with clinical hypersensitivity to brimonidine to a control group consisting 13 healthy volunteers. Blood samples were stimulated with brimonidine 0.15%, timolol 0.5% or brimonidine tartrate/timolol maleate 0.2%/0.5%. Premixed antibodies (CD63/FITC and aIgE/PE) were added for direct staining and whole-blood samples were lysed, fixed and analyzed by a flow cytometer. The basophil population was defined by high IgE cell expression. Degranulation was identified by the expression of the activation molecule CD63. RESULTS: Basophil activation was not significant when comparing percent of activated basophils of patients and healthy controls after exposure to brimonidine (2.58%, 2.45%, respectively, P=0.72). There was a significant suppression of basophil activation when a combination of brimonidine-timolol (0.87%) was compared to timolol (2.27%; P=0.012) and to brimonidine alone (2.58%; P=0.017). CONCLUSION: The results of our study do not support the hypothesis that brimonidine induces an immediate allergic reaction. Basophil activation was suppressed by the presence of ß-blockers in patients hypersensitive to brimonidine and in healthy individuals. This finding indicates that timolol suppress brimonidine drug reaction by a different mechanism.

NLRP3 inflammasome activity is upregulated in an in-vitro model of COPD exacerbation.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is an inflammatory disease characterized by a progressive and irreversible deterioration of lung function. Exacerbations of COPD have prolonged negative effects on pulmonary function and a major impact on health status and outcomes. NLRP3 inflammasome is a cardinal component of the inflammatory response, with marked evidence in stable and exacerbations of COPD. The aim of our study was to evaluate the NLRP3 inflammasome activity during COPD exacerbation by using an in vitro model. METHODS: A549 cells were stimulated with different concentrations (10%, 4%, 2%) of cigarette smoke extract (CSE) with or without LPS (0.1µg/ml) for 24 hours. Cell viability was assessed by using XTT test. Levels of inflammatory cytokines (IL-8, MCP-1, and IL-1ß) were measured by ELISA and the activity level of NLRP-3 was evaluated by flow cytometry. RESULTS: Cells exposed to CSE present an increase in inflammatory cytokines (IL-8 and MCP-1) production in a dose-dependent manner. Incubation with LPS to these cells results in higher levels of IL-8 and MCP-1 compared to stimulation of CSE alone. NLRP3 inflammasome activity and IL-1ß levels were significantly increased in cells exposed to both CSE and LPS compared to CSE alone. CONCLUSIONS: NLRP3 inflammasome is upregulated in an in-vitro model of COPD and COPD exacerbation. Our findings provide novel biomarkers for COPD exacerbation and may present new targets for future research.

Epicutaneous Exposure to Peanut Oil Induces Systemic and Pulmonary Allergic Reaction in Mice.

BACKGROUND: The prevalence of peanut allergy (PA) is constantly on the rise. Atopic dermatitis (AD) is a major risk factor for developing food allergy. Some bath oils and skin creams used for treating AD contain peanut oil, and it has been suggested that exposure to peanut allergens through a disrupted skin barrier is a potential cause of PA. Our aim was to investigate whether application of peanut oil to irritated skin causes a systemic or respiratory allergic response to peanuts in an animal model. METHODS: BALB/c mice underwent epicutaneous sensitization with either peanut oil (PM, n = 9) or phosphate buffered solution (controls, n = 9) daily for 5 consecutive days. Ten days after the last exposure the mice were challenged with intranasal peanut protein for 5 consecutive days. Bronchial alveolar lavage fluid was collected for cellular studies and measurement of cytokine levels. Sera were collected for immunoglobulin E (IgE) measurement. RESULTS: Epicutaneous peanut oil sensitization increased leukocyte and eosinophil counts and interleukin-13 levels (p = 0.003, p = 0.0006 and p = 0.03, respectively), in addition to increasing total serum IgE (p = 0.03). CONCLUSIONS: The results suggest that topical application of peanut oil may play a role in the etiology of PA.

Aging leads to impaired epicutaneous sensitization that causes attenuated allergy and pulmonary inflammation in mice.

Aging is associated with altered decreased barrier function in the skin, which can lead to different types of immunoglobulin E (IgE)-mediated sensitization to environmental allergens. Yet, allergen-specific respiratory sensitization among the elderly is not well described. The aim of this study was to investigate the effect of aging on allergic pulmonary inflammation induced by epicutaneous sensitization of mechanically irritated skin in mice. For this purpose, 6-week-, 6-month-, and 18-month-old female BALB/c mice, underwent epicutaneous sensitization with ovalbumin (OVA) or phosphate buffered saline (PBS), followed by an inhaled OVA challenge. Blood OVA-specific IgE levels measured after epicutaneous sensitization, as well as, bronchial alveolar lavage fluids (BALF) leucocyte, eosinophil, and cytokine levels measured after OVA inhalation challenge were similar among the 6-week-old (young) and 6-month-old (adult) groups. However, significantly decreased levels of systemic OVA IgE, and BALF leukocyte, eosinophil and T helper cell type 2 cytokine levels, were measured after OVA inhalation challenge in elderly (18-month-old) mice compared to the other groups of mice. In addition, interleukin-10 (IL-10), a regulatory suppressor cytokine, was more abundant in the BALF of the elderly group after epicutaneous sensitization and inhalation challenge. Our results suggest that elderly mice have a reduced allergic response to induced sensitization with OVA, possibly regulated by increased IL-10 levels.

Augmented expression of RUNX1 deregulates the global gene expression of U87 glioblastoma multiforme cells and inhibits tumor growth in mice.

Glioblastoma multiforme is the most common and aggressive primary brain tumor in adults. A mesenchymal phenotype was associated with tumor aggressiveness and poor prognosis in glioblastoma multiforme patients. Recently, the transcription factor RUNX1 was suggested as a driver of the glioblastoma multiforme mesenchymal gene expression signature; however, its independent role in this process is yet to be described. Here, we assessed the role of RUNX1 in U87 glioblastoma multiforme cells in correspondence to its mediated transcriptome and genome-wide occupancy pattern. Overexpression of RUNX1 led to diminished tumor growth in nude and severe combined immunodeficiency mouse xenograft tumor model. At the molecular level, RUNX1 occupied thousands of genomic regions and regulated the expression of hundreds of target genes, both directly and indirectly. RUNX1 occupied genomic regions that corresponded to genes that were shown to play a role in brain tumor progression and angiogenesis and upon overexpression led to a substantial down-regulation of their expression level. When overexpressed in U87 glioblastoma multiforme cells, RUNX1 down-regulated key pathways in glioblastoma multiforme progression including epithelial to mesenchymal transition, MTORC1 signaling, hypoxia-induced signaling, and TNFa signaling via NFkB. Moreover, master regulators of the glioblastoma multiforme mesenchymal phenotype including CEBPb, ZNF238, and FOSL2 were directly regulated by RUNX1. The data suggest a central role for RUNX1 as master regulator of gene expression in the U87 glioblastoma multiforme cell line and mark RUNX1 as a potential target for novel future therapies for glioblastoma multiforme.

Phospholipase A2-dependent release of inflammatory cytokines by superantigen-stimulated nasal polyps of patients with chronic rhinosinusitis.

BACKGROUND: Chronic rhinosinusitis (CRS) is an inflammatory/allergic disease with unclear pathophysiology, but it has been linked to an imbalance in the production of eicosanoids, which are metabolites of arachidonic acid, and results from phospholipids hydrolysis by phospholipase A2 (PLA2). As of yet, the role of PLA2 in CRS has hardly been studied, except for a report that group II PLA2 expression is elevated in interleukin (IL) 1ß or tumor necrosis factor α-stimulated CRS nasal tissues with and without polyps. The PLA2 families include extracellular (secretory) and intracellular isoforms, which are involved in the regulation of inflammatory processes in different ways. Here we comprehensively investigated the expression of PLA2s, particularly those reported to be involved in respiratory disorders, in superantigen (SAE)-stimulated nasal polyps from patients with CRS with polyps, and determined their role in inflammatory cytokine production by inhibition of PLA2 expression. METHODS: The release of IL-5, IL-13, IL-17, and interferon γ by nasal polyps dispersed cells (NPDC) was determined concomitantly with PLA2 messenger RNA expression, under SAE stimulation, with or without dexamethasone, as a regulator of PLA2 expression. RESULTS: Stimulation of NPDCs by SAE-induced cytokine secretion with enhanced expression of several secretory PLA2 and Ca(2+)-independent PLA2, while suppressing cytosolic PLA2 expression. All these were reverted to the level of unstimulated NPDCs on treatment with dexamethasone. CONCLUSION: This study further supports the key role of secretory PLA2 in the pathophysiology of respiratory disorders and presents secretory PLA2 inhibition as a therapeutic strategy for the treatment of CRS and airway pathologies in general.

Regulatory T cells in allergic asthma.

Defective immunological suppression can be a cause of the inflammation that leads to an allergic condition such as asthma. Suppressor regulatory T cells (Tregs) are essential for inducing and maintaining immunological tolerance to foreign and self-antigens, including allergens. Tregs are apparently altered in number and function in allergic asthmatic patients. Some treatments that ameliorate asthma symptoms lead to an increase in the number and functional impairment of Tregs, indicating that these cells play an important role in the anti-inflammatory effect of those medications.

Expression of Th17 and Treg lymphocyte subsets in hypertrophied adenoids of children and its clinical significance.

Adenoid hypertrophy is the most common cause of upper airway obstruction and sleep-disordered breathing in children, yet its pathogenesis remains unclear. The identification of the novel helper T cell subsets, Th17 cells and regulatory T cells (Tregs) could provide new insight into our understanding of the mechanisms involved in the development of this condition. The purpose of this study is to evaluate the adenoidal lymphocyte subsets to describe the percentage of various lymphocyte subsets in hypertrophied adenoids and correlate them with symptom severity. Twenty consecutive children undergoing adenoidectomy were included, and lymphocytes were isolated from their adenoids. T cell subpopulations were detected by flow cytometry using a fluoresceinated monoclonal antibody directed against a number of cell markers (CD4+, CD8+, CD25+, FOXP3 IL17+, and others). We found a significant negative linear correlation between the Th17/Treg ratio and the patients' clinical scores (R = -0.71 p < 0.005). The correlation was independent of age and gender. Decreased ratios of Th17/Treg subpopulations may play a role in the pathogenesis of adenoid hypertrophy.

Regulatory T cells: the suppressor arm of the immune system.

The existence of a population of lymphocytes with suppressor activity able to inhibit immune responses has been widely studied. The greatest advances were made when researchers proposed markers, such as CD25 and Foxp3, for identifying those suppressor T cells. Regulatory T cells (Tregs) represent approximately 10% of the CD4 T cells and are able to suppress the immune responses to self and foreign antigens. Tregs can develop and acquire a suppressor phenotype in the thymus (natural Tregs) or be induced in the periphery followed certain activation and antigen presentations conditions (induced Tregs). These cells can suppress the immunological system by two principal pathways: the direct suppression of the target cells by cell-contact, and by the secretion of suppressor cytokines. This review summarizes the published data on Tregs and its suggested role in various states of health and disease.