Aquaporin-4 knockout exacerbates corticosterone-induced depression by inhibiting astrocyte function and hippocampal neurogenesis

AIMS

The predominant expression of aquaporin-4 (AQP4) in the brain implies that this water channel may be involved in a range of brain disorders. This study was designed to investigate the role of AQP4 in the pathogenesis of depression, and related possible biological mechanism.

METHODS AND RESULTS

Wild-type (AQP4(+/+) ) and AQP4 knockout (AQP4(-/-) ) mice were given daily subcutaneous injections of corticosterone (20 mg/kg) for consecutive 21 days. Forced swimming test (FST) and tail suspension test (TST) showed longer immobility times in corticosterone-treated AQP4(-/-) genotype, indicating AQP4 knockout exacerbated depressive-like behaviors in mice. Using immunohistological staining, western blot, and enzyme-linked immunosorbent assay (ELISA), we found a significant loss of astrocytes, aggravated downregulation of excitatory amino acid transporter 2 (EAAT2), synapsin-1, and glial cell line-derived neurotrophic factor (GDNF) in the hippocampus of AQP4(-/-) mice. Moreover, even less hippocampal neurogenesis was identified in corticosterone-treated AQP4(-/-) mice in vivo and hippocampus-derived adult neural stem cells (ANSCs) in vitro.

CONCLUSIONS

The present findings suggest AQP4 involves the pathogenesis of depression by modulating astrocytic function and adult neurogenesis, highlighting a novel profile of AQP4 as a potential target for the treatment for depression.

[Field evaluation of a novel plant molluscicide "Luo-wei" against Oncomelania hupensis IV molluscicidal effect in field of river beach in Dongzhi County, Anhui Province]

OBJECTIVE

To evaluate the field effect of the plant molluscicide "Luo-wei" (tea-seed distilled saponins, TDS) against the snail Oncomelania hupensis in the river beach in Anhui Province.

METHODS

The immersing and spraying experiments were carried out in the river beach in Dongzhi County, Anhui Province, to assess the molluscicidal effect of 4% TDS comparing with 50% wettable powder of niclosamide ethanolamine salt (WPN). The chi(2) test or Fish's exact test was used to examine the differences between or among the molluscicidal effects by different environments, molluscicides, application methods, or days after the intervention. Meanwhile, the cost-effectiveness of the two molluscicides was analyzed.

RESULTS

After 1, 2 , 3 d and 7 d of the immersion, the snail death rates in both TDS group and WPN group increased gradually, the snail death rates in the two groups after immersing for 7 d were 94.62% and 99.24%, respectively, and there was no significant difference between them ( chi(2) = 3.30, P > 0.05). After 1 , 3 , 7 d and 15 d of spraying, the snail death rates were 70.82%, 79.75%, 85.11% and 91.65% in the TDS group, and 77.71%, 84.27%, 91.90% and 95.58% in the WPN group, respectively, and the differences among the snail death rates of the two groups at each time point were statistically significant (all P values < 0.05). The costs of spraying were 316.71 yuan per 100 m2 for TDS and 309.71 for WPN.

CONCLUSIONS

The molluscicidal effect of TDS has reached the requirements of national standard on nature source pesticides in the river beach of the middle and lower reaches of the Yangtze River. It is necessary to further evaluate its cost-effectiveness in large-scale field experiments in the future.

[Removal of estrogens in laccase catalyzed oxidative processes]

The removal of 5 estrogens (bisphenol A, estradiol, ethinylestradiol, estrone and octylphenol) in laccase catalyzed oxidative processes was studied. The effects of pH and NOM on the removal of EDCs were discussed in detail, as well as the kinetics of EE2 removal and the reaction products. The results indicated that laccase was capable of removing estrogens efficiently. The optimal pH was between 4 and 6. NOM significantly inhibited the removal of estrogens at the initial stage of the reaction. However, the adverse effect of NOM was not obvious after 24 h treatment. The removal of EE2 obeyed the second-order kinetics. The activity of laccase remained stable during the reactions and the stability was higher than that of peroxidase. MS analysis demonstrated that the EE2 dimer formed through radical coupling mechanism was the main reaction product.

Ketamine used as an acesodyne in human breast cancer therapy causes an undesirable side effect, upregulating anti-apoptosis protein Bcl-2 expression

Ketamine is a dissociative anesthetic agent that has been widely used in surgery and for relieving pain in chronic cancer patients. We applied ketamine to breast cancer cell line MDA-MB-231 to detect the effect of treatment and molecular mechanisms involved. We found that ketamine can upregulate the level of anti-apoptosis protein Bcl-2, which promotes breast cancer cell invasion and proliferation. Knockdown of Bcl-2 could inhibit the increase of Bcl-2 and reduce the invasion and proliferation caused by ketamine in human breast cancer cells. Our findings provide new insight into the effects of ketamine in cancer treatment; we suggest that ketamine, which has been widely used in cancer operations and for relieving pain in chronic cancer patients, may be not the best choice because it can worsen the cancer through promotion of anti-apoptosis.

Hypoxic pulmonary hypertension and novel ATP-sensitive potassium channel opener: the new hope on the horizon

Hypoxic pulmonary hypertension (HPH) is a syndrome characterized by the increase of pulmonary vascular tone and the structural remodeling of peripheral pulmonary arteries. The aim of specific therapies for hypoxic pulmonary hypertension is to reduce pulmonary vascular resistance, reverse pulmonary vascular remodeling, and thereby improving right ventricular function. Iptakalim, a lipophilic para-amino compound with a low molecular weight, has been demonstrated to be a new selective ATP-sensitive potassium (K(ATP)) channel opener via pharmacological, electrophysiological, biochemical studies, and receptor binding tests. In hypoxia-induced animal models, iptakalim decreases the elevated mean pressure in pulmonary arteries, and attenuates remodeling in the right ventricle, pulmonary arteries and airways. Furthermore, iptakalim has selective antihypertensive effects, selective vasorelaxation effects on smaller arteries, and protective effects on endothelial cells, but no effects on the central nervous, respiratory, digestive or endocrine systems at therapeutic dose. Our previous studies demonstrated that iptakalim inhibited the effects of endothelin-1, reduced the intracellular calcium concentration and inhibited the proliferation of pulmonary artery smooth muscle cells. Since iptakalim has been shown safe and effective in both experimental animal models and phase I clinical trials, it can be a potential candidate of HPH in the future.

Nicorandil prevents right ventricular remodeling by inhibiting apoptosis and lowering pressure overload in rats with pulmonary arterial hypertension

Background

Most of the deaths among patients with severe pulmonary arterial hypertension (PAH) are caused by progressive right ventricular (RV) pathological remodeling, dysfunction, and failure. Nicorandil can inhibit the development of PAH by reducing pulmonary artery pressure and RV hypertrophy. However, whether nicorandil can inhibit apoptosis in RV cardiomyocytes and prevent RV remodeling has been unclear.

Methodology/Principal Findings

RV remodeling was induced in rats by intraperitoneal injection of monocrotaline (MCT). RV systolic pressure (RVSP) was measured at the end of each week after MCT injection. Blood samples were drawn for brain natriuretic peptide (BNP) ELISA analysis. The hearts were excised for histopathological, ultrastructural, immunohistochemical, and Western blotting analyses. The MCT-injected rats exhibited greater mortality and less weight gain and showed significantly increased RVSP and RV hypertrophy during the second week. These worsened during the third week. MCT injection for three weeks caused pathological RV remodeling, characterized by hypertrophy, fibrosis, dysfunction, and RV mitochondrial impairment, as indicated by increased levels of apoptosis. Nicorandil improved survival, weight gain, and RV function, ameliorated RV pressure overload, and prevented maladaptive RV remodeling in PAH rats. Nicorandil also reduced the number of apoptotic cardiomyocytes, with a concomitant increase in Bcl-2/Bax ratio. 5-hydroxydecanoate (5-HD) reversed these beneficial effects of nicorandil in MCT-injected rats.

Conclusions/Significance

Nicorandil inhibits PAH-induced RV remodeling in rats not only by reducing RV pressure overload but also by inhibiting apoptosis in cardiomyocytes through the activation of mitochondrial ATP-sensitive K⁺ (mitoK_ATP) channels. The use of a mitoK_ATP channel opener such as nicorandil for PAH-associated RV remodeling and dysfunction may represent a new therapeutic strategy for the amelioration of RV remodeling during the early stages of PAH.

Usefulness of intravenous adenosine in idiopathic pulmonary arterial hypertension as a screening agent for identifying long-term responders to calcium channel blockers

Although intravenous adenosine is recommended for acute vasodilator testing in patients with pulmonary hypertension, long-term outcomes in acute responders treated with calcium channel blockers (CCBs) who are identified by adenosine remain unknown. In this study, the value of adenosine for identifying long-term responders to CCBs was investigated in patients with idiopathic pulmonary arterial hypertension (IPAH). All acute responders were subsequently treated with high-dose CCB monotherapy, and 6-minute walk distances, hemodynamic data, and World Health Organization functional classifications were followed. Nine of 104 patients exhibited an acute response with intravenous adenosine (8.7%, 95% confidence interval 3.2 to 14.2). After 12 months of follow-up, all acute responders were still alive; however, only 6 patients showed sustained hemodynamic improvement (5.8%, 95% confidence interval 2 to 13). Three patients had failed CCB monotherapy and bosentan was added to their treatment. Mean tolerated dose of intravenous adenosine was 142 ± 49 μg/kg/min. No life-threatening adverse events were observed and only 2 patients of the nonresponders exhibited a 20% decrease in mean systemic arterial pressure. In nonresponders, 1- and 3-year survival rates were 89% and 75%, respectively. In conclusion, acute vasodilator testing with intravenous adenosine was safe and able to screen responders to CCB therapy in patients with IPAH. Long-term CCB responders accounted for about 5.8% of patients with IPAH.

Iptakalim rescues human pulmonary artery endothelial cells from hypoxia-induced nitric oxide system dysfunction

The aim of this study was to assess whether hypoxia inhibits endothelial nitric oxide synthase (eNOS) activity and nitric oxide (NO) production, and whether iptakalim may rescue human pulmonary artery endothelial cells (HPAECs) from hypoxia-induced NO system dysfunction. HPAECs were cultured under hypoxic conditions in the absence or presence of 0.1, 10 and 1,000 μM iptakalim or the combination of 10 μM iptakalim and 1, 10 and 100 μM glibenclamide for 24 h, and the eNOS activity and NO levels were measured in the conditioned medium from the HPAEC cultures. The eNOS activity and NO levels were reduced significantly in the conditioned medium from HPAEC cultures under hypoxic conditions. Pre-treatment with 10 μM iptakalim normalized the reduction of the eNOS activity and NO levels caused by hypoxia in the conditioned medium from HPAEC cultures. Iptakalim raised the eNOS activity and NO levels under hypoxic conditions, but was blocked by the K(ATP) channel blocker, glibenclamide. Our results indicate that hypoxia impairs NO system function, whereas the ATP-sensitive K(+) channel opener, iptakalim, may rescue HPAECs from hypoxia-induced NO system dysfunction.

Survival of Chinese patients with pulmonary arterial hypertension in the modern treatment era

BACKGROUND

In a previous study of Chinese patients with idiopathic pulmonary arterial hypertension (IPAH) in the nontargeted therapy era (defined as the time before 2006 when new pulmonary arterial hypertension-specific drugs were not available in China), we reported 1- and 3-year survival estimates of only 68% and 39%, respectively. However, it is not yet known whether the survival of patients with pulmonary arterial hypertension is improved in the modern treatment era (defined in China as after 2006).

METHODS

A retrospective cohort study was undertaken in 276 consecutive patients with newly diagnosed incident IPAH and connective tissue disease-related pulmonary arterial hypertension (CTDPAH) who were referred between 2007 and 2009. Baseline characteristics and survival rates in the two groups were compared.

RESULTS

The 1- and 3-year survival estimates were 92.1% and 75.1%, respectively, in patients with IPAH, and 85.4% and 53.6%, respectively, in patients with CTDPAH. Patients with CTDPAH had a significantly lower mean pulmonary artery pressure, more pericardial effusion, and more severe impairment of the diffusion capacity of the lung for carbon monoxide than patients with IPAH. A diagnosis of CTDPAH, World Health Organization functional class III or IV, single-breath diffusion capacity of the lung for carbon monoxide < 80% predicted, and the presence of pericardial effusion were independent predictors of mortality. The 1- and 3-year survival rates of male patients were 93.5% and 77.5%, respectively, in those with IPAH, and 71.1% and 47.4%, respectively, in those with CTDPAH.

CONCLUSIONS

The survival rates of patients with pulmonary arterial hypertension have improved in China in the modern treatment era, despite the high costs of treatment and financial constraints. However, the survival rates of patients with CTDPAH are inferior to those of patients with IPAH. Our study also indicates poorer survival rates in male patients with CTDPAH.

[Meta-analysis on interleukin-4 receptor α chain Q576R gene polymorphisms and bronchial asthma susceptibility]

OBJECTIVE

to study the association between interleukin-4 receptor α chain (IL-4RA) Q576R polymorphisms and bronchial asthma susceptibility by Meta-analysis.

METHODS

four medical databases, including Pubmed, Embase, CNKI and Wanfang, were searched for the case-control studies about the IL-4RA polymorphisms and bronchial asthma susceptibility. Odds ratios (OR) of IL-4RA Q576R genotype distributions in asthma patients against healthy controls were analyzed in both RR vs QR + QQ model and QR + RR vs QQ model. Analyses were performed for asthma in general and for subgroups based on the atopy status of the asthma population. The sensitivity analysis and the publication bias tests were conducted.

RESULTS

fifteen case-control studies, with 2675 asthma cases, 1202 atopic asthma cases and 331 nonatopic asthma cases respectively, were identified and all control group genotype frequencies were consistent with Hardy-Weinberg equilibrium. In genotype RR vs QR + QQ model no heterogeneity among the studies was found, while in genotype QR + RR vs QQ model, heterogeneity among these studies was found. These studies were analyzed by fixed-effect model (RR vs QR + QQ model) or random-effect model (QR + RR vs QQ model). The pooled odds ratio of IL-RA Q576R genotype RR vs QR + QQ was 2.02 (95%CI: 1.53 - 2.66), and the pooled odds ratio in this model in the atopic asthma subgroup was 2.26 (95%CI: 1.47 - 3.49), while the pooled odds ratio (QR + RR vs QQ model) was 1.02 (95%CI: 1.06 - 1.53).

CONCLUSION

a meta-analysis of results from case-control studies strongly supports the conclusion that IL-4RA Q576R polymorphisms impart a modest yet significant risk for asthma.

[Research in high frequency ultrasonic for degradation of azo dye wastewater containing MX-5B]

The degradation of azo dye wastewater, containing MX-5B, was investigated by using high frequency ultrasonic irradiation. The effect of different factors like the initial pH of solution, sonolysis parameters, air-blowing, Fe2+ concentration were studied, the synergistic action of complex frequency and the mechanism of degradation was explored primarily. The results show that MX-5B in aqueous solution can be degraded efficiently by ultrasonic irradiation, when the pH 3.5, ultrasonic frequency 418.3 kHz, ultrasonic power 69 W, color removal rate up to 100% in 180 min. Adding of Fe2+ and blowing air had some effects. The results also indicated that radical-oxidation controlled the ultrasonic decompose of MX-5B and MX-5B ultrasonic removal was observed to behave as pseudo-first-order kinetics under different experimental conditions tested in the present work. Comparison of UV-Vis absorption spectrums before and after treatment showed that all of the conjugate structure and part of aromatic structure were destroyed after being ultrasonic irradiation.

[Pulmonary coccidioidomycosis:a case report and review of the literature]

OBJECTIVE

To improve the understanding of the clinical manifestations of pulmonary coccidioidomycosis.

METHODS

A case of pulmonary coccidioidomycosis was reported, and the literature was reviewed. The epidemiologic, clinical and diagnostic aspects of coccidioidomycosis were discussed.

RESULTS

A 74 year old male was admitted to the hospital because of physical examination revealing lung space occupying lesions for 9 months and cough for 2 weeks. Lung puncture biopsy was carried out and the diagnosis of cryptococcosis was established in another hospital. After 6 months' therapy with fluconazole, the chest CT showed no change. After being hospitalized, thoracoscopic wedge resection of lung was performed and the final diagnosis was pulmonary coccidioidomycosis. After the surgery, he was immediately started on voriconazole 200 mg daily for 1 month. Then oral fluconazole was prescribed for 5 months. A follow-up chest CT performed 6 months after surgery was normal.

CONCLUSIONS

Coccidioidomycosis is uncommon. It's pathological appearance is similar to cryptococcus. With the extensive using of immune suppressive drugs, we should improve the recognition of coccidioidomycosis.

Investigation of spectra unfolded for a filtered x-ray diode array with improved smoothness

An unfolding algorithm using parabolic B-splines to smoothly reconstruct the soft x-ray spectra from the measurements of a filtered x-ray diode array is proposed. This array has been fabricated for the study of the soft x ray emitted by Z-pinch plasma. Unfolding results show that for the simulated noise-free blackbody spectra with temperature ranging from 20 to 250 eV, both the spectra and the total power are accurately recovered. Typical experimental waveforms along with the unfolded spectra and total power of x rays are presented. Possible defects due to the adoption of parabolic B-splines instead of conventionally used histograms are discussed.

Arsenic trioxide, a potent inhibitor of NF-kappaB, abrogates allergen-induced airway hyperresponsiveness and inflammation

Background

Overactivation of nuclear factor κB (NF-κB) orchestrates airway eosinophilia, but does not dampen airway hyperresponsiveness in asthma. NF-κB repression by arsenic trioxide (As₂O₃) contributes to apoptosis of eosinophils (EOS) in airways. Here we provide evidence that As₂O₃ abrogates allergen (OVA)-induced airway eosinophilia by modulating the expression of IκBα, an NF-κB inhibitory protein, and decreases the airway hyperresponsiveness.

Methods

Using a murine model of asthma, the airway hyperresponsiveness was conducted by barometric whole-body plethysmography. Airway eosinophilia, OVA-specific IgE in serum, and chemokine eotaxin and RANTES (regulated upon activation, normal T cell expressed and secreted) in bronchoalveolar lavage fluid were measured by lung histology, Diff-Quick staining, and ELISA. Chemokine-induced EOS chemotactic activity was evaluated using EOS chemotaxis assay. Electrophoretic mobility shift assay and Western blot analysis were performed to assess pulmonary NF-κB activation and IκBα expression, respectively.

Results

As₂O₃ attenuated the allergen-induced serum IgE, chemokine expression of eotaxin and RANTES, and the EOS recruitment in bronchoalveolar lavage fluid, which is associated with an increased IκBα expression as well as a decreased NF-κB activation. Also, As₂O₃ suppressed the chemotaxis of EOS dose-dependently in vitro. Additionally, As₂O₃ significantly ameliorated the allergen-driven airway hyperresponsiveness, the cardinal feature underlying asthma.

Conclusion

These findings demonstrate an essential role of NF-κB in airway eosinophilia, and illustrate a potential dissociation between airway inflammation and hyperresponsiveness. As₂O₃ likely exerts its broad anti-inflammatory effects by suppression of NF-κB activation through augmentation of IκBα expression in asthma.

Effects of adenoviral gene transfer of mutated IkappaBalpha, a novel inhibitor of NF-kappaB, on human monocyte-derived dendritic cells

AIM

To investigate the effects of adenoviral gene transfer of IkappaBalpha mutant (IkappaBalphaM), a novel inhibitor of nuclear factor kappaB (NF-kappaB), on apoptosis, phenotype and function of human monocyte-derived dendritic cells (DC).

METHODS

Monocytes, cocultured with granulocyte/macrophage colony-stimulating factor (GM-CSF; 900 ng/mL) and interleukin (IL)-4 (300 ng/mL) for 5 d, followed by stimulation with lipopolysaccharide (LPS; 100 ng/mL) for 2 d differentiated into mature DC. Monocytes were either left untransfected or were transfected with AdIkappaBalphaM or AdLacZ. The transcription and expression of the IkappaBalphaM gene, and the inhibitory effect of IkappaBalphaM on tumor necrosis factor (TNF)-alpha-induced NF-kappaB activation in mature DC were detected by polymerase chain reaction (PCR), reverse transcription-polymerase chain reaction (RT-PCR), Western blot analysis, and electrophoretic mobility shift assays, respectively. The phenotype, apoptosis, IL-12 secretion level of DC, and ability to stimulate the proliferation of T cells were determined by flow cytometry, enzyme-linked immunosorbent assay and mixed leukocyte reaction.

RESULTS

PCR and RT-PCR were used to detect a unique 801 bp band in AdIkappaBalphaM-transfected mature DC, and also a dose- and time-dependent expression of the IkappaBalphaM gene, which peaked at a multiplicity of infection of 100 pfu/cell and at 48 h. Furthermore, AdIkappaBalphaM significantly suppressed the TNF-alpha-induced NF-kappaB activation, augmented apoptosis, downregulated CD80, CD83, and CD86 surface molecules, IL-12 secretion levels and the ability to stimulate the proliferation of T cells in mature DC.

CONCLUSION

AdIkappaBalphaM effectively transfected and potently inhibited NF-kappaB activation in monocyte-derived mature DC. Overexpression of the IkappaBalphaM gene in mature DC may contribute to T-cell immunosuppression through induction of DC apoptosis and downregulation of B7 molecules, providing a potential strategy for future DC-based immunotherapy of asthma.