Excess hydrogen sulfide and polysulfides production underlies a schizophrenia pathophysiology

Mice with the C3H background show greater behavioral propensity for schizophrenia, including lower prepulse inhibition (PPI), than C57BL/6 (B6) mice. To characterize as-yet-unknown pathophysiologies of schizophrenia, we undertook proteomics analysis of the brain in these strains, and detected elevated levels of Mpst, a hydrogen sulfide (H₂ S)/polysulfide-producing enzyme, and greater sulfide deposition in C3H than B6 mice. Mpst-deficient mice exhibited improved PPI with reduced storage sulfide levels, while Mpst-transgenic (Tg) mice showed deteriorated PPI, suggesting that "sulfide stress" may be linked to PPI impairment. Analysis of human samples demonstrated that the H₂ S/polysulfides production system is upregulated in schizophrenia. Mechanistically, the Mpst-Tg brain revealed dampened energy metabolism, while maternal immune activation model mice showed upregulation of genes for H₂ S/polysulfides production along with typical antioxidative genes, partly via epigenetic modifications. These results suggest that inflammatory/oxidative insults in early brain development result in upregulated H₂ S/polysulfides production as an antioxidative response, which in turn cause deficits in bioenergetic processes. Collectively, this study presents a novel aspect of the neurodevelopmental theory for schizophrenia, unraveling a role of excess H₂ S/polysulfides production.

P1809Impact of mitral regurgitation on clinical outcome in patients with cardiac sarcoidosis

Background

Mitral regurgitation (MR) is sometimes observed in cardiac sarcoidosis (CS), and might be related to worsening heart failure. However, mechanism and clinical significance of MR associated with CS remains undetermined.

Methods

We retrospectively analyzed consecutive 51 CS patients, and identified 16 patients with moderate to severe MR evaluated by quantitative echocardiography. According to the assessment of coaptation point and tenting height, main mechanisms of the 16 patients with MR were classified into prolapse (P) in 5, and tethering in 11 (T). Prednisolone was started from 30 mg/day, gradually tapered over a period of 6 months to a maintenance dose of 5 to 10 mg/day and continued a lifetime.

Results

At the first visit, patients with MR showed higher incidence of NYHA class IV heart failure as compared to those without MR (56 vs. 9%, p<0.001). Abnormal uptake of fluorine-18 fluorodeoxyglucose in the papillary muscle was more frequent in patients with MR than those without MR (63% vs. 23%, p<0.05). Patients with tethering MR showed higher incidence of complete atrioventricular block (T: 74% vs. P: 40% vs. without MR: 31%, p<0.05), significantly reduced left ventricular (LV) ejection fraction (T: 33±7% vs. P: 52±9% vs. without MR: 52±16%, p<0.001) and increased LV end-diastolic volume index (T: 100±52ml/m2 vs. P: 66±23ml vs. without MR: 62±21ml, p<0.001). During the mean follow-up of 108 months, cardiac-event free survival was significantly worse in patients with tethering MR as compared to the other patients (log-rank; 11.7, p<0.001). Six of the 11 patients with tethering MR received cardiac resynchronization therapy, and then did not experience further hospitalization due to decompensated heart failure for at least 2 years. Multivariate analysis identified tethering MR as an independent predictor of cardiac event (HR: 6.7, p<0.05).

Conclusions

MR associated with CS has variety of mechanisms including prolapse, tethering and inflammation of the LV papillary muscle, and may be related to ventricular remodeling and poor clinical outcome.

[Signaling molecules hydrogen sulfide (H2S), polysulfides (H2Sn), and sulfite (H2SO3)]

More than twenty years have passed since the demonstration of hydrogen sulfide (H₂S) as a signaling molecule. Various roles of this molecule have been reported including neuromodulation, vascular relaxation, cytoprotection, anti-inflammation, and oxygen sensing. During the study of its effect on neuromodulation, we found TRP channels as a target of H₂S, and later identified polysulfides (H₂S_n) as chemical entity of the ligand. We found that H₂S relaxes vasculatures in synergy with NO, and recently identified H₂S_n as products produced by the chemical interaction between H₂S and NO to exert the effect, suggesting that it may be a mechanism for the synergy between the two molecules. It has attracted attention that sulfite, a further metabolite of H₂S and H₂S_n, protects neurons from oxidative stress by a mechanism different from that by H₂S and H₂S_n.

Performance verification of a precise vibrating-wire magnet alignment technique for next-generation light sources

The high-accuracy alignment of magnets is a key issue in the development of next-generation light-source rings. To obtain adequate dynamic apertures, the magnets must be aligned to an accuracy of 10 µm or better. Recently, a new technique that utilizes a vibrating wire has attracted attention for this purpose as it can directly determine with high resolution the magnetic centers in a series of multipole magnets on a straight section between bending magnets. In conventional vibrating-wire alignment techniques, wire sag, which causes alignment errors, is determined from the theoretical catenary curve. By contrast, in the present study, we have measured the sag profiles of various wires in the longitudinal direction to micrometer-order accuracy. We concluded that we can reduce deviations of the actual wire sag from the theoretical curve by choosing a suitable wire. By setting up a test bench of a vibrating-wire alignment system for a series of multipole magnet on a straight section, we have achieved the total error of the magnetic-center measurements of micrometer-order in the standard deviation. Moreover, two systematic error factors, the drift of the magnetic centers due to thermal deformations of the magnets after they are excited and the change in the magnetic centers due to reassembly of the magnets after installing the vacuum chamber, are included in practical magnet alignments. We have experimentally investigated these error factors using the test bench.

An open-type microdevice to improve the quality of fluorescence labeling for axonal transport analysis in neurons

Abnormal axonal transport of vesicles as well as organelles in a particular set of neurons is implicated in the pathogenesis of many neurodegenerative diseases such as amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease. Although various types of microfluidic multicompartmental devices with closed microchannels have been recently developed and widely used for axonal transport analysis, most of the existing devices are troublesome and time-consuming to handle, such as culture maintenances, sample collections, and immunocytochemistry. In this study, we overcome such inherent shortcomings by developing a novel open-type device that enables easy cell maintenance and sample collections. In our device, microgrooves instead of microchannels were directly fabricated on a glass substrate, thereby making possible a high-resolution optical observation. Compared with the conventional closed-type devices, our newly designed device allowed us to efficiently and precisely label the axonal acidic vesicles by fluorescent dyes, facilitating a high-throughput analysis of axonal vesicular transport. The present novel device, as a user-friendly and powerful tool, can be implemented in molecular and cellular pathogenesis studies on neurological diseases.

Signalling by hydrogen sulfide and polysulfides via protein S-sulfuration

Hydrogen sulfide (H₂ S) is a signalling molecule that regulates neuronal transmission, vascular tone, cytoprotection, inflammatory responses, angiogenesis, and oxygen sensing. Some of these functions have recently been ascribed to its oxidized form polysulfides (H₂ S_n ), which can be produced by 3-mercaptopyruvate sulfurtransferase (MPST), also known as a H₂ S-producing enzyme. H₂ S_n activate ion channels, tumour suppressors, transcription factors, and protein kinases. H₂ S_n S-sulfurate (S-sulfhydrate) cysteine residues of these target proteins to modify their activity by inducing conformational changes through the formation of a disulfide bridge between the two cysteine residues involved. The chemical interaction between H₂ S and NO also generates H₂ S_n , which may be a chemical entity that exerts the synergistic effect of H₂ S and NO. MPST also produces redox regulators cysteine persulfide (CysSSH), GSH persulfide (GSSH), and persulfurated proteins. In addition to MPST, haemoproteins such as haemoglobin, myoglobin, neuroglobin, and catalase as well as SOD can produce H₂ S_n , and sulfide quinone oxidoreductase and cysteinyl tRNA synthetase can make GSSH and CysSSH. This review focuses on the recent progress in the study of the production and physiological roles of these persulfurated and polysulfurated molecules. LINKED ARTICLES: This article is part of a themed section on Hydrogen Sulfide in Biology & Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.4/issuetoc.

Treatment-free remission after two-year consolidation therapy with nilotinib in patients with chronic myeloid leukemia: STAT2 trial in Japan

The purpose of this trial was to evaluate the efficacy of 2-year consolidation therapy with nilotinib, at a dose of 300 mg twice daily, for achieving treatment-free remission in chronic myeloid leukemia patients with a deep molecular response (BCR-ABL1^IS ≤0.0032%). Successful treatment-free remission was defined as no confirmed loss of deep molecular response. We recruited 96 Japanese patients, of whom 78 sustained a deep molecular response during the consolidation phase and were therefore eligible to discontinue nilotinib in the treatment-free remission phase; of these, 53 patients (67.9%; 95% confidence interval: 56.4–78.1%) remained free from molecular recurrence in the first 12 months. The estimated 3-year treatment-free survival was 62.8%. Nilotinib was readministered to all patients (n=29) who experienced a molecular recurrence during the treatment-free remission phase. After restarting treatment, rapid deep molecular response returned in 25 patients (86.2%), with 50% of patients achieving a deep molecular response within 3.5 months. Tyrosine kinase inhibitor withdrawal syndrome was reported in 11/78 patients during the early treatment-free remission phase. The treatment-free survival curve was significantly better in patients with undetectable molecular residual disease than in patients without (3-year treatment-free survival, 75.6 versus 48.6%, respectively; P=0.0126 by the log-rank test). There were no significant differences in treatment-free survival between subgroups based on tyrosine kinase inhibitor treatment before the nilotinib consolidation phase, tyrosine kinase inhibitor-withdrawal syndrome, or absolute number of natural killer cells. The results of this study indicate that it is safe and feasible to stop tyrosine kinase inhibitor therapy in patients with chronic myeloid leukemia who have achieved a sustained deep molecular response with 2 years of treatment with nilotinib. This study was registered with UMIN-CTR (UMIN000005904).

Sulfite protects neurons from oxidative stress

BACKGROUND AND PURPOSE

Hydrogen sulfide (H₂ S) and polysulfides (H₂ S_n ) are signalling molecules that mediate various physiological responses including cytoprotection. Their oxidized metabolite sulfite (SO₃ ^2- ) is found in blood and tissues. However, its physiological role remains unclear. In this study, we investigated the cytoprotective effect of sulfite on neurons exposed to oxidative stress caused by high concentrations of the neurotransmitter glutamate, known as oxytosis.

EXPERIMENTAL APPROACH

Concentrations of sulfite as well as those of cysteine and GSH in rats were measured by HPLC. Cytoprotective effects of sulfite on primary cultures of rat neurons against oxytosis was examined by WST-8 cytoprotective and LDH cytotoxicity assays and compared with that of H₂ S, H₂ S_n and thiosulfate.

KEY RESULTS

Free sulfite, present at approximately 2 μM in the rat brain, converts cystine to cysteine more efficiently than H₂ S and H₂ S_n and facilitates transport of cysteine into cells. Physiological concentrations of sulfite protected neurons from oxytosis and were accompanied by increased intracellular concentrations of cysteine and GSH probably due to converting extracellular cystine to cysteine, more efficiently than H₂ S and H₂ S_n . In contrast, thiosulfate only slightly protected neurons from oxytosis.

CONCLUSIONS AND IMPLICATIONS

Our present data have shown sulfite to be a novel cytoprotective molecule against oxytosis, through maintaining cysteine levels in the extracellular milieu, leading to increased intracellular cysteine and GSH. Although there may be adverse clinical effects in sensitive individuals, our results provide a new insight into the therapeutic application of sulfite to neuronal diseases caused by oxidative stress.

LINKED ARTICLES

This article is part of a themed section on Chemical Biology of Reactive Sulfur Species. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.4/issuetoc.

Multifield Control of Domains in a Room-Temperature Multiferroic 0.85BiTi0.1Fe0.8Mg0.1O3-0.15CaTiO3 Thin Film

Single-phase materials that combine electric polarization and magnetization are promising for applications in multifunctional sensors, information storage, spintronic devices, etc. Following the idea of a percolating network of magnetic ions (e.g., Fe) with strong superexchange interactions within a structural scaffold with a polar lattice, a solid solution thin film with perovskite structure at a morphotropic phase boundary with a high level of Fe atoms on the B site of perovskite structure is deposited to combine both ferroelectric and ferromagnetic ordering at room temperature with magnetoelectric coupling. In this work, a 0.85BiTi_0.1Fe_0.8Mg_0.1O₃-0.15CaTiO₃ thin film has been deposited by pulsed laser deposition (PLD). Both the ferroelectricity and the magnetism were characterized at room temperature. Large polarization and a large piezoelectric effective coefficient d₃₃ were obtained. Multifield coupling of the thin film has been characterized by scanning force microscopy. Ferroelectric domains and magnetic domains could be switched by magnetic field ( H), electric field ( E), mechanical force ( F), and, indicating that complex cross-coupling exists among the electric polarization, magnetic ordering and elastic deformation in 0.85BiTi_0.1F_e0.8Mg_0.1O₃-0.15CaTiO₃ thin film at room temperature. This work also shows the possibility of writing information with electric field, magnetic field, and mechanical force and then reading data by magnetic field. We expect that this work will benefit information applications.

Prospective predictors of exacerbation status in severe asthma over a 3-year follow-up

BACKGROUND

A predisposition to exacerbations is being recognized as a distinct phenotype with "previous exacerbations" representing the strongest clinical factor associated with future exacerbation. Thus, to identify additional novel biomarkers associated with asthma exacerbations, "past exacerbation status" must be included as a confounding factor.

OBJECTIVE

This study aimed to characterize the clinical and biomarker features associated with asthma exacerbations in severe asthma.

METHODS

We evaluated clinical parameters from 105 severe asthmatics yearly for 3 years, as well as their exacerbation status. We classified the subjects into 3 groups: (i) consistent non-exacerbators (CNE, subjects who did not experience any exacerbation over the 3-year period); (ii) consistent frequent exacerbators (CFE, subjects with frequent exacerbation, defined as those who had 2 or more exacerbations within 1 year, throughout the 3-year period); and (iii) intermittent exacerbators (IE). We conducted multivariate analysis for comparisons among the groups for multiple factors, including several Th2-related biomarkers, in addition to the "past exacerbation status."

RESULTS

Thirty-nine subjects were classified as CNE, 15 as CFE, and 51 as IE. Frequent exacerbations in the previous year predicted exacerbations for the following year (P < .001). Among the several Th2-related biomarkers, only FeNO was associated with exacerbation status. When we analysed the data after the second visit, the impact of FeNO on predicting future exacerbation remained significant, even after considering the exacerbation status during the first year (P < .05).

CONCLUSIONS AND CLINICAL RELEVANCE

Measurement of FeNO has a significant potential to predict future asthma exacerbation, which is independent of the "past exacerbation history."