Neuronal Modulators from the Coral-Associated Fungi Aspergillus candidus

Three new p-terphenyl derivatives, named 4″-O-methyl-prenylterphenyllin B (1) and phenylcandilide A and B (17 and 18), and three new indole-diterpene alkaloids, asperindoles E-G (22-24), were isolated together with eighteen known analogues from the fungi Aspergillus candidus associated with the South China Sea gorgonian Junceela fragillis. The structures and absolute configurations of the new compounds were elucidated on the basis of spectroscopic analysis, and DFT/NMR and TDDFT/ECD calculations. In a primary cultured cortical neuronal network, the compounds 6, 9, 14, 17, 18 and 24 modulated spontaneous Ca²⁺ oscillations and 4-aminopyridine hyperexcited neuronal activity. A preliminary structure-activity relationship was discussed.

MicroRNA-506-3p inhibits proliferation and promotes apoptosis in ovarian cancer cell via targeting SIRT1/AKT/FOXO3a signaling pathway

Ovarian cancer (OC) is one of the most common tumors in females. Growing evidence shows that microRNA-506-3p (miR-506-3p) is downregulated in OC tissues. The purpose of this study was to investigate the mechanism of miR-506-3p in modulating OC. Quantitative reverse transcriptase PCR (qRT-PCR) was employed to investigate the expression of miR-506-3p and its target in OC tissues or cell lines. CCK-8 or colony formation assay was used to examine cell viability or proliferation, respectively. Flow cytometry was demonstrated to detect cell apoptosis. Western blot was then applied to analyze underlying mechanisms. The potential target of miR-506-3p was examined via luciferase reporter assay. MiR-506-3p was significantly downregulated in both human OC tissues and cell lines. Overexpression of miR-506-3p not only decreased cell viability of OC cell lines but also promoted cell apoptosis, thus inhibiting OC progression. Moreover, SIRT1 (Sirtuin 1) was found to be a direct target of miR-506-3p, and SIRT1 expression was negatively regulated by miR-506-3p in OC cell lines. Further investigation revealed that overexpression of SIRT1 could promote cell viability as well as inhibit cell apoptosis, showing the reversed effect on OC progression compared to miR-506-3p. Lastly, AKT (Protein kinase B) /FOXO3a (Forkhead box O3) signaling pathway was inactivated by miR-506-3p while activated by SIRT1, relating to regulation of miR-506-3p on OC progression. Our results revealed a novel mechanism by which miR-506-3p inhibited proliferation while promoted apoptosis of OC via inactivation of SIRT1/AKT/FOXO3a signaling pathway, suggesting that miR-506-3p might be a potential target for OC.

[The mechanism of nicotine on human bronchial smooth muscle cell contraction]

Objective: To investigate the molecular mechanism of contractility dysfunction of human bronchial smooth muscle cells induced by nicotine. Methods: Primary human bronchial smooth muscle cells were cultured in vitro. The cells were divided into a control group and a nicotine group which was treated with 10(-5) mol/L nicotine for 48 h and transfected with or without α7nAChR-siRNA (The siNC group, siNC + nicotine group and siα7nAChR + nicotine group). The effects of nicotine on the cell contractile function were examined by collagen gel shrinkage assay. The expressions of α7nAChR and TRPC6 protein in nicotine-treated human bronchial smooth muscle cells were detected by Western blotting. The change of intracellular calcium concentration by nicotine was detected by calcium ion imaging system.Data were analyzed by t test or single factor analysis of variance. Results: The area of collagen gel in the nicotine group (24±8)% was significantly lower than that in the control group (59±14)% (t=3.78, P<0.05). Compared with the control group, the expression of α7nAChR protein in nicotine-induced group (173±16)% was significantly higher than that of controls 100±0)%, t=-6.848, P<0.05. Compared with the siNC group [(72±10)%, (0.79±0.07), (0.41±0.04) and (0.17±0.02) respectively], the collagen gel area of siNC + nicotine group was significantly reduced by (37±10)%. However, the basal calcium level (1.04±0.02), store operated calcium entry level (SOCE, 0.68±0.03) and receptor operated calcium entry level (ROCE, 0.36±0.02) were remarkably elevated in the nicotine treated group (all P<0.05). Furthermore, compared with siNC + nicotine group, the area of collagen gel in siα7nAChR + nicotine group was significantly increased (62±10)%, and the basal calcium level (0.78±0.06), SOCE level (0.39±0.05) and ROCE level (0.15±0.02) were significantly reduced (all P<0.05). Conclusions: Nicotine can increase the expression of TRPC6 protein, SOCE and ROCE level, and increase the intracellular calcium concentration by upregulating the expression of α7nAChR protein, thereby promoting smooth muscle cell contraction.

[Chronic hypoxia increases intracellular Ca(2+) concentration and augments proliferation by enhancing store-operated Ca(2+) entry in pulmonary arterial smooth muscle cells]

OBJECTIVE

To determine whether store-operated Ca(2+) entry (SOCE) is involved in chronic hypoxia-induced alteration of intracellular Ca(2+) concentration ([Ca(2+) ]i) and proliferation in pulmonary arterial smooth muscle cells (PASMC).

METHODS

Rat PASMCs were cultured and treated in normoxia (21%O2) or hypoxia (4%O2) condition. The proliferation of PASMC was detected by cell counting kit-8 (CCK-8) assay. [Ca(2+) ]i, SOCE and the effects of store-operated Ca(2+) channel (SOCC) inhibitors, SKF96365 and NiCl2, on SOCE in hypoxic PASMCs were tested by InCyte [Ca(2+) ]i measurement system.

RESULTS

Hypoxia for 24-60 h augmented PASMC proliferation (1.12±0.09 vs 0.71±0.05, P<0.05) and [Ca(2+) ]i [(214.8 ± 20.4) nmol/L vs (115.2±13.2) nmol/L, P<0.05] in a time-dependent manner with the maximum effect at 60 h. Perfusion of Ca(2+) -free Krebs solution containing nifedipine (5 μmol/L), cyclopiazonic acid (CPA, 10 μmol/L) in PASMCs caused a small transient increase of [Ca(2+) ]i with peak [Ca(2+) ]i (113.3±49.3) nmol/L.Chronic hypoxia (4% O2, 60 h) enhanced [Ca(2+) ]i level with peak value of (193.2±22.7) nmol/L (P<0.05) in PASMC.After restoration of extracellular Ca(2+) , CPA caused marked increase of [Ca(2+) ]i with peak value of (328.0 ±56.7) nmol/L.Chronic hypoxia strengthened CPA-induced increase of [Ca(2+) ]i with peak value of (526.0±33.7) nmol/L (P<0.05) in PASMCs.Either SKF96365 50 μmol/L or NiCl2 500 μmol/L distinctly attenuated CPA-induced enhancement of [Ca(2+) ]i, the peak value of which dropped from (526.0±33.7) nmol/L to (170.4±26.4) nmol/L (P<0.05) or (177.4±45.9) nmol/L (P<0.05) respectively.

CONCLUSION

Chronic hypoxia boosts the release of Ca(2+) from sarcoplasmic reticulum and promotes the activity of SOCC and SOCE, leading to [Ca(2+) ]i elevation and proliferation of rat PASMCs.

Three-dimensional visualization of rat brain microvasculature following permanent focal ischaemia by synchrotron radiation

OBJECTIVE

Identifying morphological changes that occur in microvessels under both normal and ischaemic conditions is crucial for understanding and treating stroke. However, conventional imaging techniques are not able to detect microvessels on a micron or sub-micron scale without angiography. In the present study, synchrotron radiation (SR)-based X-ray in-line phase contrast imaging (ILPCI) was used to acquire high-resolution and high-contrast images of rat brain tissues in both normal and ischaemic states.

METHODS

ILPCI was performed at the Shanghai Synchrotron Radiation Facility, Shanghai, China, without the use of contrast agents. CT slices were reformatted and then converted into three-dimensional (3D) reconstruction images to analyse subtle details of the cerebral microvascular network.

RESULTS

By using ILPCI, brain vessels up to 11.8 μm in diameter were resolved. The number of cortical and penetrating arteries detected were found to undergo a remarkable decrease within the infarct area. 3 days after permanent ischaemia, vascular masses were also observed in the peripheral region of the infarcts.

CONCLUSION

SR-based ILPCI-CT can serve as a powerful tool to accurately visualize brain microvasculature. The morphological parameters of blood vessels in both CT slices and 3D reconstructions were determined, and this approach has great potential for providing an effective diagnosis and evaluation for rehabilitation therapy for stroke.

ADVANCES IN KNOWLEDGE

In the absence of contrast agent, the 3D morphologies of the brain microvasculature in normal and stroke rats were obtained using SR-based ILPCI. SR imaging is a sensitive and promising method which can be used to explore primary brain function.

Genetoxicity of water samples from the scenic Lijang river in the Guilin area, China, evaluated by Tradescantia bioassays

The Lijang river which passes through the Guilin mountains, and Guilin city is a world renowned scenic spot on the southwest border of China. The river and its tributaries receive water from the mountain tops and springs underground. The river water was clean two decades ago before the development of industrial establishments and extra heavy tourism. Deforestation over the mountain tops on the upper stream and its tributaries in the last decades has created serious erosion and increased sedimentation in the river. In the present study, the Tradescantia micronucleus (Trad-MCN) and Tradescantia stamen hair mutation (Trad-SHM) assays were used to evaluate the genetoxicity of water samples collected from 60 different sites along the river. Results indicate that most of the water samples from the tributaries were highly mutagenic, and that pollutants had accumulated in the main river in the Guilin city area from the industrial effluent and city sewage. Both the Trad-MCN and Trad-SHM assays were highly effective for the detection of mutagens in the water samples.

Safety of a live-attenuated Japanese encephalitis virus vaccine (SA14-14-2) for children

In a study begun in 1985, 1,026 children between the ages of 5 and 12 years, living in an area of low Japanese encephalitis (JE) infection, were vaccinated with live-attenuated JE vaccine, strain SA14-14-2. A group of 47 of the vaccinated children, 5-6 years of age, were examined for fever and other systemic reactions every other day for 2 weeks following vaccination. None of these children had temperatures greater than 37.4 degrees C or other systemic reactions during the observation period. No untoward reactions were reported in the remainder of the vaccinated group. After immunization, seroconversion rates in seronegative children were 100% (GMT 35.3, n = 11), 100% (GMT 31.7, n = 12), and 83.3% (GMT 23, n = 10) in groups receiving vaccine diluted 1:3, 1:5, and 1:50, respectively. These results indicate that the JE SA14-14-2 live-attenuated vaccine is immunogenic and safe for children.