Chloride ion transport and overexpression of TMEM16A in a guinea-pig asthma model

BACKGROUND

TMEM16A, a Ca-activated Cl channel, regulates various physiological functions such as mucin secretion. However, the role of TMEM16A in hyper-secretion in asthma is not fully understood.

OBJECTIVE

The aim of this study is to evaluate Cl ion transport via TMEM16A and determine the localization of TMEM16A in a guinea-pig asthma model.

METHODS

Guinea-pigs were sensitized with ovalbumin (OVA) i.p. on Days 1 and 8. On Day 22, we assessed OVA challenge-induced Cl ion transport in the sensitized tracheas ex vivo in an Ussing chamber, compared with the non-sensitized tracheas. We then examined the effect of T16Ainh-A01, a TMEM16A inhibitor, on the increase in Cl ion transport. The tracheal epithelium was immunostained with an anti-TMEM16A antibody. Epithelial cells from guinea-pig tracheas were cultured at the air-liquid interface in the presence of IL-13 for in vitro study. We studied the effect of TMEM16A inhibitors on Ca-dependent agonist, uridine triphosphate (UTP)-induced increases in Cl ion transport in the cultured cells. The cells were immunostained with an anti-TMEM16A antibody, an anti-MUC5AC antibody and an anti-α-tubulin antibody.

RESULTS

OVA challenge induced an increase in short circuit current within 1 min in the OVA-sensitized tracheas but not in the non-sensitized tracheas, which was inhibited by pretreatment of T16Ainh-A01. Sensitized tracheas showed goblet cell metaplasia with more positive TMEM16A immunostaining, particularly in the apical portion compared with the non-sensitized tracheas. The in vitro UTP-induced increase in Cl ion transport was strongly inhibited by pretreatment with T16Ainh-A01, benzbromarone, and niflumic acid. TMEM16A was positively immunostained at the apical portion and in the MUC5AC-positive area in IL-13-induced goblet cell metaplasia.

CONCLUSIONS

Antigen challenge and Ca-dependent agonist treatment increased Cl ion transport via the overexpression of TMEM16A in goblet cell metaplasia in a guinea-pig asthma model. TMEM16A inhibitors may be useful for the treatment of hyper-secretion in asthma.

Two-step egg introduction for prevention of egg allergy in high-risk infants with eczema (PETIT): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Evidence is accumulating that early consumption is more beneficial than is delayed introduction as a strategy for primary prevention of food allergy. However, allergic reactions caused by early introduction of such solid foods have been a problematic issue. We investigated whether or not early stepwise introduction of eggs to infants with eczema combined with optimal eczema treatment would prevent egg allergy at 1 year of age.

METHODS

In this randomised, double-blind, placebo-controlled trial, we enrolled infants 4-5 months of age with eczema from two centres in Japan. Exclusion criteria were being born before 37 weeks of gestational age, experience of ingestion of hen's eggs or egg products, history of immediate allergic reaction to hen's eggs, history of non-immediate allergic reaction to a particular type of food, and complications of any severe disease. Infants were randomly assigned (block size of four; stratified by institution and sex) to early introduction of egg or placebo (1:1). Participants in the egg group consumed orally 50 mg of heated egg powder per day from 6 months to 9 months of age and 250 mg per day thereafter until 12 months of age. We aggressively treated participants' eczema at entry and maintained control without exacerbations throughout the intervention period. Participants and physicians were masked to assignment, and allocation was concealed. The primary outcome was the proportion of participants with hen's egg allergy confirmed by open oral food challenges at 12 months of age, assessed blindly by standardised methods, in all randomly allocated participants who received the intervention. This trial is registered with the University Hospital Medical Information Network Clinical Trials Registry, number UMIN000008673.

FINDINGS

Between Sept 18, 2012, and Feb 13, 2015, we randomly allocated 147 participants (73 [50%] to the egg group and 74 [50%] to the placebo group). This trial was terminated on the basis of the results of the scheduled interim analysis of 100 participants, which showed a significant difference between the two groups (four [9%] of 47 participants had an egg allergy in the egg group vs 18 [38%] of 47 in the placebo group; risk ratio 0·222 [95% CI 0·081-0·607]; p=0·0012). In the primary analysis population, five (8%) of 60 participants had an egg allergy in the egg group compared with 23 (38%) of 61 in the placebo group (risk ratio 0·221 [0·090-0·543]; p=0·0001). The only difference in adverse events between groups was admissions to hospital (six [10%] of 60 in the egg group vs none in the placebo group; p=0·022). 19 acute events occurred in nine (15%) participants in the egg group versus 14 events in 11 (18%) participants in the placebo group after intake of the trial powder.

INTERPRETATION

Introduction of heated egg in a stepwise manner along with aggressive eczema treatment is a safe and efficacious way to prevent hen's egg allergy in high-risk infants. In this study, we developed a practical approach to overcome the second wave of the allergic epidemic caused by food allergy.

FUNDING

Ministry of Health, Labour and Welfare, and National Centre for Child Health and Development, Japan.

Transepidermal water loss measurement during infancy can predict the subsequent development of atopic dermatitis regardless of filaggrin mutations

BACKGROUND

Atopic dermatitis (AD) is characterized by skin barrier dysfunction. Few studies have used noninvasive techniques to measure epidermis function in asymptomatic neonates.

METHODS

Data of 116 infants from our previous randomized controlled study were analyzed. Skin barrier function was measured through transepidermal water loss (TEWL), stratum corneum hydration (SCH), and pH. The association between skin barrier function and time to AD development was evaluated. Patients were classified with high or low TEWL, and SCH and pH were assessed. The survival function of the time to AD development and hazard ratios were estimated. Allergic sensitization to egg white and ovomucoid at 32 weeks was assessed.

RESULTS

Regardless of a filaggrin mutation, TEWL (optimal cutoff, 6.5 g/m(2)/h) of the forehead within the first week of life showed a lower p-value than TEWL of the leg, and the SCH and pH measurements. Baseline TEWL of the forehead was not different between groups, except for the mean gestational age, and it was not affected by humidity. We found a significant difference in the cumulative AD incidence between the high and low TEWL groups for the forehead only (p < 0.05). The probability without AD was lower in the high TEWL group than in the low TEWL group. For only the high TEWL group, AD development decreased significantly with daily emollient use. The high TEWL group exhibited a higher rate of sensitization to ovomucoid (p = 0.07).

CONCLUSIONS

TEWL of the forehead during the first week of life is associated with AD development.

The 5-HT3 receptor is essential for exercise-induced hippocampal neurogenesis and antidepressant effects

Exercise has a variety of beneficial effects on brain structure and function, such as hippocampal neurogenesis, mood and memory. Previous studies have shown that exercise enhances hippocampal neurogenesis, induces antidepressant effects and improves learning behavior. Brain serotonin (5-hydroxytryptamine, 5-HT) levels increase following exercise, and the 5-HT system has been suggested to have an important role in these exercise-induced neuronal effects. However, the precise mechanism remains unclear. In this study, analysis of the 5-HT type 3A receptor subunit-deficient (htr3a(-/-)) mice revealed that lack of the 5-HT type 3 (5-HT3) receptor resulted in loss of exercise-induced hippocampal neurogenesis and antidepressant effects, but not of learning enhancement. Furthermore, stimulation of the 5-HT3 receptor promoted neurogenesis. These findings demonstrate that the 5-HT3 receptor is the critical target of 5-HT action in the brain following exercise, and is indispensable for hippocampal neurogenesis and antidepressant effects induced by exercise. This is the first report of a pivotal 5-HT receptor subtype that has a fundamental role in exercise-induced morphological changes and psychological effects.

Low-dose CT screening using hybrid iterative reconstruction: confidence ratings of diagnoses of simulated lesions other than lung cancer

OBJECTIVE

To evaluate the confidence ratings of diagnoses of simulated lesions other than lung cancer on low-dose screening CT with hybrid iterative reconstruction (IR).

METHODS

Simulated lesions (emphysema, mediastinal masses and interstitial pneumonia) in a chest phantom were scanned by a 320-row area detector CT. The scans were performed by 64-row and 160-row helical scans at various dose levels and were reconstructed by filtered back projection (FBP) and IR. Emphysema, honeycombing and reticular opacity were visually scored on a four-point scale by six thoracic radiologists. The ground-glass opacity as a percentage of total lung volume (%GGO), CT value and contrast-to-noise ratio (CNR) of mediastinal masses were calculated. These scores and values were compared between FBP and IR. Wilcoxon's signed-rank test was used (p < 0.05). Interobserver agreements were evaluated by κ statistics.

RESULTS

There were no significant differences in visual assessment. Interobserver agreement was almost perfect. CT values were almost equivalent between FBP and IR, whereas CNR with IR was significantly higher than that with FBP. %GGO significantly increased at low-dose levels with FBP; however, IR suppressed the elevation.

CONCLUSION

The confidence ratings of diagnoses of simulated lesions other than lung cancer on low-dose CT screening were not degraded with hybrid IR compared with FBP.

ADVANCES IN KNOWLEDGE

Hybrid IR did not degrade the confidence ratings of diagnoses on visual assessment and differential diagnoses based on CT value of mediastinal masses, and it showed the advantage of higher GGO conspicuity at low-dose level. Radiologists can analyse images of hybrid IR alone on low-dose CT screening for lung cancer.

Novel homozygous mutation, c.400C>T (p.Arg134*), in the PVRL1 gene underlies cleft lip/palate-ectodermal dysplasia syndrome in an Asian patient

Cleft lip/palate-ectodermal dysplasia syndrome is a rare, autosomal recessive disorder caused by homozygous loss-of-function mutations of the poliovirus receptor-like 1 (PVRL1) gene encoding nectin-1. Nectin-1 is a cell-cell adhesion molecule that is important for the initial step in the formation of adherens junctions and tight junctions; it is expressed in keratinocytes, neurons, and the developing face and palate. Clinical manifestations comprise a unique facial appearance with cleft lip/palate, ectodermal dysplasia, cutaneous syndactyly of the fingers and/or toes, and in some cases, mental retardation. We present the first report, to our knowledge, of an Asian individual with cleft lip/palate-ectodermal dysplasia syndrome with a novel PVRL1 mutation. A 7-year-old Japanese boy, the first child of a consanguineous marriage, showed hypohidrotic ectodermal dysplasia with sparse, brittle, fine, dry hair and hypodontia, the unique facial appearance with cleft lip/palate, cutaneous syndactyly of the fingers and mild mental retardation. Scanning electron microscopic examination of the hair demonstrated pili torti and pili trianguli et canaliculi. Mutation analysis of exon 2 of PVRL1 revealed a novel homozygous nonsense mutation, c.400C>T (p.Arg134*). His parents were heterozygous for the mutant alleles. All four PVRL1 mutations identified in cleft lip/palate-ectodermal dysplasia syndrome to date, including this study, resulted in truncated proteins that lack the transmembrane domain and intracellular domain of nectin-1, which is necessary to initiate the cell-cell adhesion process.

[A Case of an Elderly Diabetic Patient Developing Wernicke Encephalopathy without Alcohol Abuse or an Unbalanced Diet]

A 70-year-old man with a 28-year history of type 2 diabetes mellitus was admitted due to persistent vomiting and neurological abnormalities in Nov 2012. He had developed gait disturbance and diplopia for six months during antiplatelet therapy, which was initiated following the diagnosis of a cerebellar infarction in June 2012. He had nystagmus, truncal ataxia and an ocular motility disorder, and the MRI study showed increased FLAIR and DWI signals in the peri-third ventricle and periaqueductal region, in addition to the cerebellar vermis. Wernicke encephalopathy was suspected according to his symptoms, and thiamine administration dramatically improved his condition. He did not have a history of alcohol abuse or poor eating habits; however, various coexisting factors, including diabetes mellitus, pyloric stenosis and the use of antiulcer drugs and insulin, were considered to be responsible for Wernicke encephalopathy. This case demonstrates the importance of distinguishing Wernicke encephalopathy from cerebrovascular disease in elderly patients.

Morphological and functional changes in regenerated primary afferent fibres following mental and inferior alveolar nerve transection

BACKGROUND

It is important to know the mechanisms underlying pain abnormalities associated with inferior alveolar nerve (IAN) regeneration in order to develop the appropriate treatment for orofacial neuropathic pain patients. However, peripheral mechanisms underlying orofacial pain abnormalities following IAN regeneration are not fully understood.

METHODS

Head withdrawal threshold (HWT), jaw opening reflex (JOR) thresholds, single-fibre recordings of the regenerated mental nerve (MN) fibres, calcitonin gene-related peptide (CGRP), isolectin B4 (IB4), peripherin, neurofilament-200 (NF-200) and transient receptor potential vanilloid 1 (TRPV1) expression in trigeminal ganglion (TG) cells, and electron microscopic (EM) observations of the regenerated MN fibres were studied in MN- and IAN-transected (M-IANX) rats.

RESULTS

HWT to mechanical or heat stimulation of the mental skin was significantly lower in M-IANX rats compared with sham rats. Mean conduction velocity of action potentials recorded from MN fibres (n = 124) was significantly slower in M-IANX rats compared with sham rats. The percentage of Fluoro-Gold (FG)-labelled CGRP-, peripherin- or TRPV1-immunoreactive (IR) cells was significantly larger in M-IANX rats compared with that of sham rats, whereas that of FG-labelled IB4- and NF-200-IR cells was significantly smaller in M-IANX rats compared with sham rats. Large-sized myelinated nerve fibres were rarely observed in M-IANX rats, whereas large-sized unmyelinated nerve fibres were frequently observed and were aggregated in the bundles at the distal portion of regenerated axons.

CONCLUSIONS

These findings suggest that the demyelination of MN fibres following regeneration may be involved in peripheral sensitization, resulting in the orofacial neuropathic pain associated with trigeminal nerve injury.

Increased Syk phosphorylation leads to overexpression of TRAF6 in peripheral B cells of patients with systemic lupus erythematosus

OBJECTIVE

Activation of B cells is a hallmark of systemic lupus erythematosus (SLE). Syk and TRAF6 are key signaling molecules in B-cell activation through BCR and CD40/TLR, respectively. Nevertheless, whether expression of Syk and TRAF6 is altered in SLE B cells remains unknown.

METHODS

Phosphorylation and/or expression of Syk and TRAF6 were analyzed by flow cytometry in peripheral blood mononuclear cells isolated from SLE patients.

RESULTS

Pronounced phosphorylation and expression of Syk were noted in B cells from SLE patients compared with healthy donors. Levels of Syk phosphorylation correlated with the disease activity score. TRAF6 was significantly over-expressed in B cells of SLE patients as compared with healthy donors, and significant correlation of levels of TRAF6 expression and Syk phosphorylation was observed in SLE patients. Levels of TRAF6 expression were more pronounced in CD27+ memory B cells than in CD27-naïve B cells. In vitro treatment of SLE B cells with a Syk inhibitor (BAY61-3606) reduced Syk phosphorylation as well as TRAF6 expression.

CONCLUSION

Our results suggest that the activated Syk-mediated TRAF6 pathway leads to aberrant activation of B cells in SLE, and also highlight Syk as a potential target for B-cell-mediated processes in SLE.

Six-axis multi-anvil press for high-pressure, high-temperature neutron diffraction experiments

We developed a six-axis multi-anvil press, ATSUHIME, for high-pressure and high-temperature in situ time-of-flight neutron powder diffraction experiments. The press has six orthogonally oriented hydraulic rams that operate individually to compress a cubic sample assembly. Experiments indicate that the press can generate pressures up to 9.3 GPa and temperatures up to 2000 K using a 6-6-type cell assembly, with available sample volume of about 50 mm(3). Using a 6-8-type cell assembly, the available conditions expand to 16 GPa and 1273 K. Because the six-axis press has no guide blocks, there is sufficient space around the sample to use the aperture for diffraction and place an incident slit, radial collimators, and a neutron imaging camera close to the sample. Combination of the six-axis press and the collimation devices realized high-quality diffraction pattern with no contamination from the heater or the sample container surrounding the sample. This press constitutes a new tool for using neutron diffraction to study the structures of crystals and liquids under high pressures and temperatures.