Akiko Sano

Role of Mitogen-Activated Protein Kinase-Mediated Cytosolic Phospholipase A2 Activation in Arachidonic Acid Metabolism in Human Eosinophils

The objective of this investigation was to determine the role of secretory and cytosolic isoforms of phospholipase A2 (PLA2) in the induction of arachidonic acid (AA) and leukotriene synthesis in human eosinophils and the mechanism of PLA2 activation by mitogen-activated protein kinase (MAPK) isoforms in this process. Pharmacological activation of eosinophils with fMLP caused increased AA release in a concentration (EC50 = 8.5 nM)- and time-dependent (t1/2 = 3.5 min) manner. Both fMLP-induced AA release and leukotriene C4 (LTC4) secretion were inhibited concentration dependently by arachidonic trifluoromethyl ketone, a cytosolic PLA2 (cPLA2) inhibitor; however, inhibition of neither the 14-kDa secretory phospholipase A2 by 3-(3-acetamide-1-benzyl-2-ethylindolyl-5-oxy)propanephosphonic acid nor cytosolic Ca2+-independent phospholipase A2 inhibition by bromoenol lactone blocked hydrolysis of AA or subsequent leukotriene synthesis. Pretreatment of eosinophils with a mitogen-activated protein/extracellular signal-regulated protein kinase (ERK) kinase inhibitor, U0126, or a p38 MAPK inhibitor, SB203580, suppressed both AA production and LTC4 release. fMLP induced phosphorylation of MAPK isoforms, ERK1/2 and p38, which were evident after 30 s, maximal at 1–5 min, and declined thereafter. fMLP stimulation also increased cPLA2 activity in eosinophils, which was inhibited completely by 30 μM arachidonic trifluoromethyl ketone. Preincubation of eosinophils with U0126 or SB203580 blocked fMLP-enhanced cPLA2 activity. Furthermore, inhibition of Ras, an upstream GTP-binding protein of ERK, also suppressed fMLP-stimulated AA release. These findings demonstrate that cPLA2 activation causes AA hydrolysis and LTC4 secretion. We also find that cPLA2 activation caused by fMLP occurs subsequent to and is dependent upon ERK1/2 and p38 MAPK activation. Other PLA2 isoforms native to human eosinophils possess no significant activity in the stimulated production of AA or LTC4.

Extracellular Signal-Regulated Kinase 1/2-Mediated Phosphorylation of Cytosolic Phospholipase A2 Is Essential for Human Eosinophil Adhesion to Fibronectin

We examined the role of p38, p42, and p44 mitogen-activated protein kinase (MAPK) isoforms and cytosolic phospholipase A2 (cPLA2) activation in human eosinophil adhesion to plate-coated fibronectin (FN). In the control state, eosinophil adhesion was maximal, with 10 μg/ml FN at 30 min, and decreased after 60–90 min. Western blot analysis demonstrated that p44/42 MAPK (extracellular signal-regulated kinase (ERK)1/2) and cPLA2 were phosphorylated during adhesion to FN, whereas p38 MAPK phosphorylation was unchanged. Preincubation of eosinophils with U0126 or PD98059, two structurally unrelated MAPK kinase inhibitors, or arachidonic trifluoromethyl ketone, a cPLA2 inhibitor, blocked eosinophil adhesion to FN. By contrast, eosinophil adhesion was unaffected by SB203580, a p38 MAPK inhibitor. Pretreatment of eosinophils with okadaic acid, a serine/threonine phosphatase inhibitor, at the concentrations that induced ERK1/2 and cPLA2 phosphorylation caused an increase in maximal eosinophil adhesion to FN for >60 min. MAPK kinase inhibition but not p38 inhibition also blocked FN-mediated F-actin redistribution in eosinophils and prevented cPLA2 phosphorylation caused by adhesion to FN. These results demonstrate that ERK1/2 mediating cPLA2 activation is essential for eosinophil adhesion to FN.

The Strategy for Predicting Future Exacerbation of Asthma Using a Combination of the Asthma Control Test and Lung Function Test

Background. Various factors have been reported to be useful for predicting future exacerbations. Objective. This study was intended to determine a usefulness of a combination of a patient-based questionnaire, such as the Asthma Control Test (ACT) score with objective assessments, such as forced expiratory volume in 1 second (FEV1) and/or exhaled nitric oxide (FENO), for predicting future exacerbations in adult asthmatics. Methods. We therefore enrolled 78 subjects with mild to moderate asthma, who were clinically stable for 3 months who all had been regularly receiving inhaled steroid treatment. All subjects underwent a routine assessment of asthma control including the ACT score, spirometry, and FENO, and then were followed up until a severe exacerbation occurred. The predictors of an increased risk of severe exacerbation were identified and validated using decision trees based on a classification and regression tree (CART) analysis. The properties of the developed models were the evaluated with the area under the ROC curve (AUC) (95% confidence interval [CI]). Results. The CART analysis automatically selected the variables and cut-off points, the ACT score ≤23 and FEV1 ≤ 91.8%, with the greatest capacity for discriminating future exacerbations within one year or not. When the probalility was calculated by the likelihood ratio of a positive test (LP), the ACT score ≤23 was identified with a 60.3% probability, calculated by 1.82 of LP, whereas the combined ACT score ≤23 and the percentage of predicted FEV1 ≤ 91.8% were identified with an 85.0% probability, calculated by an LP score of 5.43, for predicting future exacerbation. Conclusion. These results demonstrated that combining the ACT score and percentage of predicted FEV1, but not FENO, can sufficiently stratify the risk for future exacerbations within one year.

Non-genomic inhibitory effect of glucocorticoids on activated peripheral blood basophils through suppression of lipid raft formation

We investigated the non‐genomic effects of glucocorticoids (GCs) on inhibition of plasma membrane lipid raft formation in activated human basophils. Human basophils obtained from house dust mite (HDM)‐sensitive volunteers were pretreated with hydrocortisone (CORT) or dexamethasone (Dex) for 30 min and then primed with phorbol 12‐myristate 13‐acetate (PMA, 10 ng/ml) or HDM (10 µg/ml). The expression of CD63, a basophil activation marker, was assessed by flow cytometry. Membrane‐bound GC receptors (mGCRs) were analysed by flow cytometry and confocal laser microscopy. Lipid rafts were assessed using a GM1 ganglioside probe and visualization by confocal laser microscopy. Pretreatment of basophils with CORT (10−4 M and 10−5 M) and Dex (10−7 M) significantly inhibited CD63 expression 20 min after addition of PMA or HDM. The inhibitory effects of GCs were not altered by the nuclear GC receptor (GCR) antagonist RU486 (10−5 M) or the protein synthesis inhibitor cycloheximide (10−4 M) (P < 0·05). CORT coupled to bovine serum albumin (BSA‐CORT) mimicked the rapid inhibitory effects of CORT, suggesting the involvement of mGCRs. mGCRs were detectable on the plasma membrane of resting basophils and formed nanoclusters following treatment with PMA or HDM. Pretreatment of cells with BSA‐CORT inhibited the expression of mGCRs and nanoclustering of ganglioside GM1 in lipid rafts. The study provides evidence that non‐genomic mechanisms are involved in the rapid inhibitory effect of GCs on the formation of lipid raft nanoclusters, through binding to mGCRs on the plasma membrane of activated basophils.

Exertional dyspnoea and cortical oxygenation in patients with COPD

This study was designed to investigate the association of perceived dyspnoea intensity with cortical oxygenation and cortical activation during exercise in patients with chronic obstructive pulmonary disease (COPD) and exertional hypoxaemia. Low-intensity exercise was performed at a constant work rate by patients with COPD and exertional hypoxaemia (n=11) or no hypoxaemia (n=16), and in control participants (n=11). Cortical oxyhaemoglobin (oxy-Hb) and deoxyhaemoglobin (deoxy-Hb) concentrations were measured by multichannel near-infrared spectroscopy. Increased deoxy-Hb is assumed to reflect impaired oxygenation, whereas decreased deoxy-Hb signifies cortical activation. Exercise decreased cortical deoxy-Hb in control and nonhypoxaemic patients. Deoxy-Hb was increased in hypoxaemic patients and oxygen supplementation improved cortical oxygenation. Decreased deoxy-Hb in the pre-motor cortex (PMA) was significantly correlated with exertional dyspnoea in control participants and patients with COPD without hypoxaemia. In contrast, increased cortical deoxy-Hb concentration was correlated with dyspnoea in patients with COPD and hypoxaemia. With the administration of oxygen supplementation, exertional dyspnoea was correlated with decreased deoxy-Hb in the PMA of COPD patients with hypoxaemia. During exercise, cortical oxygenation was impaired in patients with COPD and hypoxaemia compared with control and nonhypoxaemic patients; this difference was ameliorated with oxygen supplementation. Exertional dyspnoea was related to activation of the pre-motor cortex in COPD patients. Exertional dyspnoea was related to activation of the pre-motor cortex in COPD patients http://ow.ly/QUHfC

Paraneoplastic pemphigus associated with Castleman disease: Progression from mucous to mucocutaneous lesions with epitope-spreading phenomena

Paraneoplastic pemphigus (PNP) is a frequently fatal autoimmune blistering disease of the skin and mucous membranes.1 PNP is commonly associated with malignant neoplasms or haematological disorders like Castleman disease (CD). The eruptions may resemble those seen in various other conditions such as lichen planus (LP), graft-versus-host disease, erythema multiforme (EM), bullous pemphigoid and pemphigus vulgaris (PV).2 This article is protected by copyright. All rights reserved.

Influence of comorbidities on the efficacy of pulmonary rehabilitation in patients with chronic obstructive pulmonary disease

To evaluate the influence of comorbidities and aging on pulmonary rehabilitation (PR) efficacy in patients with chronic obstructive pulmonary disease (COPD).

A scoring algorithm for predicting the presence of adult asthma: a prospective derivation study

Background: To predict the presence of asthma in adult patients with respiratory symptoms, we developed a scoring algorithm using clinical parameters. Methods: We prospectively analysed 566 adult outpatients who visited Kinki University Hospital for the first time with complaints of nonspecific respiratory symptoms. Asthma was comprehensively diagnosed by specialists using symptoms, signs, and objective tools including bronchodilator reversibility and/or the assessment of bronchial hyperresponsiveness (BHR). Multiple logistic regression analysis was performed to categorise patients and determine the accuracy of diagnosing asthma. Results: A scoring algorithm using the symptom-sign score was developed, based on diurnal variation of symptoms (1 point), recurrent episodes (2 points), medical history of allergic diseases (1 point), and wheeze sound (2 points). A score of ≥3 had 35% sensitivity and 97% specificity for discriminating between patients with and without asthma and assigned a high probability of having asthma (accuracy 90%). A score of 1 or 2 points assigned intermediate probability (accuracy 68%). After providing additional data of forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio <0.7, the post-test probability of having asthma was increased to 93%. A score of 0 points assigned low probability (accuracy 31%). After providing additional data of positive reversibility, the post-test probability of having asthma was increased to 88%. Conclusions: This pragmatic diagnostic algorithm is useful for predicting the presence of adult asthma and for determining the appropriate time for consultation with a pulmonologist.

Paraneoplastic pemphigus presenting lichen planus-like lesions

patch test was recommended but he refused. He did not want topical immunotherapy inducing an allergic response. Therefore, tofacitinib 5 mg twice daily was prescribed. After 1 month, hair growth first began at the area of contact dermatitis; this became more conspicuous after 2 months (Fig. 1b). After 5 months, complete regrowth was achieved (Fig. 1c) and was well-maintained during 4 additional months of tofacitinib administration. Then, the patient was lost to follow up. There is some evidence that contact dermatitis can help to treat AA. For example, the therapeutic effect of allergic contact dermatitis (ACD) from diphenylcyclopropenone on AA is wellknown. Similarly, ACD from wig adhesive tape demonstrated an incidental therapeutic effect on AA. Antigenic competition and alteration of the cytokine milieu during the resolution of ACD may ameliorate the follicular autoimmune reaction. A recent gene-level study supported this: negative immune regulation transcripts showed greater relative expression than activation transcripts during the resolution of ACD. These targets may be modulated by RNA interference to promote hair growth. Irritant contact dermatitis (ICD) can also induce hair growth in AA (e.g. anthralin), but its mechanism is less clear. Although early stage ACD is distinguished from ICD by the presence of a sensitization phase, later stage ACD in the elicitation phase manifests similarly to ICD, sharing cytokines and chemokines. Moreover, regulatory cytokines are produced to limit inflammation during repeated irritant application, which may regulate the autoimmune process of AA. Notably, either contact dermatitis or tofacitinib alone might have improved AA. However, we suspect that tofacitinib and contact dermatitis acted synergistically to restore hair growth because hair began to grow from the area of contact dermatitis only after tofacitinib administration. Tofacitinib significantly downregulates genetic expression of various pro-inflammatory mediators in the affected skin. Therefore, immune downregulation with tofacitinib might have acted as an RNA interference signal, encouraging the inhibition of follicular autoimmune reactions during the resolution of contact dermatitis. The reverse interaction is also plausible. Interestingly, we detected a similar phenomenon, wherein tofacitinib caused more rapid hair growth within psoriatic plaques in an AA patient with psoriasis. Unfortunately, we could not define the nature of the contact dermatitis because the patient refused a patch test. Although silicone is generally known as an inert material, several case reports of silicone-induced ACD exist. However, ICD is also possible because the lesion was limited to the contact site. To our knowledge, this is the first case report of the synergistic effect of contact dermatitis and oral tofacitinib in AA. Further accumulation of cases is necessary to elucidate details of their synergistic effects and mechanism of inducing hair growth.

Accuracy of objective tests for diagnosing adult asthma in symptomatic patients: A systematic literature review and hierarchical Bayesian latent-class meta-analysis

BACKGROUND We obtain summary estimates of the accuracy of additional objective tests for the diagnosis of adult asthma using systematic review and meta-analysis of diagnostic test accuracy studies. METHODS Medline, Embase, and other relevant electronic databases were searched for papers published between January 1989 and December 2016. Studies were included if they evaluated the diagnostic accuracy of objective tests, including airway reversibility (AR), airway hyperresponsiveness (AHR), and fractionated exhaled nitric oxide (FeNO) for the diagnosis of adult asthma in patients with symptoms suggestive of asthma. If papers were assessed appropriate using the adapted QUADAS-2 tool, meta-analysis was conducted using the hierarchical bivariate model. This hierarchical model accounts for both within and between study variability. RESULTS Sixteen studies reported the performance of the evaluated objective tests at presentation. For diagnosis of adult asthma, overall sensitivity and specificity for AR were 0.39 (95% confidence interval [CI] 0.18 to 0.66) and 0.95 (95% CI 0.86 to 1.00); for AHR, 0.86 (95% CI 0.61 to 1.00) and 0.95 (95% CI 0.77 to 1.00); for FeNO, 0.65 (95% CI 0.53 to 0.77) and 0.83 (95% CI 0.75 to 0.90). Comprehensive comparison of three diagnostic tools for adult asthma using the back-calculated likelihood rate (LR) showed that AR and AHR corresponded to a higher LR+, and AHR gave a lower LR-. CONCLUSIONS In the current situation of no gold standard for diagnosis of adult asthma, AR and AHR are appropriate for ruling-in the true diagnosis, and AHR is superior for ruling-out a diagnosis. Since each objective test had a specific characteristic, it should be chosen depending on the situation, such as the capacity of the institution and the conditions of patients.