Hsa_circ_0002468 Regulates the Neuronal Differentiation of SH-SY5Y Cells by Modulating the MiR-561/E2F8 Axis.

BACKGROUND It has been shown that circular RNAs (circRNAs) play a vital role in the regulation of neuronal differentiation; however, the precise role of circRNAs in human neuronal differentiation remains largely unexplored. MATERIAL AND METHODS A dual-luciferase reporter assay was carried out to confirm the targets of hsa_circ_0002468, miR-561, E2F8 (E2F transcription factor 8, a protein coding gene), and miR-561. We detected the expression of hsa_circ_0002468, miR-561, and E2F8 by using quantitative real-time polymerase chain reaction (qRT-PCR) analyses. In addition, we performed the functional experiments by using a BrdU (5-bromo-2'-deoxyuridine) assay and qRT-PCR analyses. RESULTS In this study, we showed that hsa_circ_0002468 can act as a sponge of miR-561 to regulate SH-SY5Y proliferation and differentiation. A bioinformatics analysis showed that hsa_circ_0002468 had a binding site that corresponded to miR-561, which was verified by dual-luciferase reporter assay. The expression of hsa_circ_0002468 was increased during SH-SY5Y differentiation and was inversely correlated with miR-561 expression. Using qRT-PCR analysis, we showed that hsa_circ_0002468 negatively regulated miR-561 in SH-SY5Y cells. Intriguingly, the overexpression of hsa_circ_0002468 increased SH-SY5Y differentiation and reduced SH-SY5Y proliferation; the suppression of hsa_circ_0002468 led to decreased SH-SY5Y differentiation levels and increased SH-SY5Y proliferation levels. Additionally, overexpression of miR-561 rescued the SH-SY5Y proliferation deficiency induced by hsa_circ_0002468 overexpression and abolished the SH-SY5Y differentiation promoted by hsa_circ_0002468. Furthermore, E2F8 was validated as a direct target of miR-561. CONCLUSIONS Our data suggested that hsa_circ_0002468 was a novel circRNA that regulated SH-SY5Y cell proliferation and differentiation via targeting the miR-561/E2F8 axis. Therefore, manipulating hsa_circ_0002468 in SH-SY5Y cells could be a novel strategy to develop novel interventions for the treatment of relevant neurological disorders.

Synthesis of a hollow-structured flower-like Fe3O4@MoS2 composite and its microwave-absorption properties.

In order to realize the characteristics of new types of wave-absorbing materials, such as strong absorption, broad bandwidth, low weight and small thickness, a hollow-structured flower-like Fe3O4@MoS2 composite was successfully prepared by simple solvothermal and hydrothermal methods in this paper. The structural properties were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Besides, the microwave properties and magnetic properties were measured using a vector network analyzer and via a hysteresis loop. SEM and TEM images revealed that MoS2 nanosheets grew on the surface of hollow nanospheres. The results showed that the composite exhibited excellent absorbing property. When the molar ratio of Fe3O4 and MoS2 was 1 : 18, the minimum reflection loss value reached -49.6 dB at 13.2 GHz with a thickness of 2.0 mm and the effective absorption bandwidth was 4.24 GHz (11.68-15.92 GHz). Meanwhile, the effective absorption in the entire X-band (8-12 GHz) and part of the C-band (4-8 GHz) and Ku-band (12-18 GHz) could be achieved by designing the sample thickness. In addition, the hollow structure effectively reduced the density of the material, which was in line with the current development trend of absorption materials. It could be predicted that the hollow core-shell structure composite has a potential application prospect in the field of microwave absorption.

Synthesis of a super-absorbent nanocomposite hydrogel based on vinyl hybrid silica nanospheres and its properties.

Superabsorbent polymers as soft materials that can absorb water have aroused great interest in the fields of agriculture and forestry. Water absorption and water retention performance of a hydrogel are important indicators to evaluate its practical application. However, few reports show that hydrogels have both excellent water absorption and water retention properties. To date, superabsorbent hydrogels with a swelling capacity of more than 3000 g g-1 have rarely been reported. In this work, a novel superabsorbent poly(acrylic acid) (PAA)-based nanocomposite hydrogel (NC gel) was prepared via free radical polymerization of acrylic acid by using vinyl hybrid silica nanospheres (VSNPs) as the cross-linking agent. The PAA NC hydrogel achieved a great swelling ratio of more than 5000 times in deionized water at 323 K, and the swollen hydrogel could hold 60% moisture when it was exposed to the air at 303 K for 42 h. Moreover, the hydrogel also obtained a good swelling ratio of 136 g g-1 in NaCl solution. The PAA NC hydrogel showed excellent repetitive swelling ability. The influences of variable factors (acrylic acid, initiator and sodium hydroxide) on the swelling ratio of the NC hydrogel were researched. It can be speculated that the PAA NC hydrogel has potential application in agriculture and forestry areas due to its excellent water absorption and water retention properties.

Capsaicin and dihydrocapsaicin induce apoptosis in human glioma cells via ROS and Ca2+­mediated mitochondrial pathway.

Human glioma is the most common type of primary brain tumor and one of the most invasive and aggressive tumors, which, even with treatments including surgery, radiotherapy and chemotherapy, often relapses and exhibits resistance to conventional treatment methods. Developing novel strategies to control human glioma is, therefore, an important research focus. The present study investigated the mechanism of apoptosis induction in U251 human glioma cells by capsaicin (Cap) and dihydrocapsaicin (DHC), the major pungent ingredients of red chili pepper, using the Cell Counting Kit­8 assay, transmission electron microscopy analysis, flow cytometry analysis, laser scanning confocal microscope analysis and immunohistochemical staining. Treatment of U251 glioma cells with Cap and DHC resulted in a dose­ and time­dependent inhibition of cell viability and induction of apoptosis, whereas few effects were observed on the viability of L929 normal murine fibroblast cells. The apoptosis­inducing effects of Cap and DHC in U251 cells were associated with the generation of reactive oxygen species, increased Ca2+ concentrations, mitochondrial depolarization, release of cytochrome c into the cytosol and activation of caspase­9 and ­3. These effects were further confirmed by observations of the anti­tumor effects of Cap and DHC in vivo in a U251 cell murine tumor xenograft model. These results demonstrate that Cap and DHC are effective inhibitors of in vitro and in vivo survival of human glioma cells, and provide the rationale for further clinical investigation of Cap and DHC as treatments for human glioma.

[Study on the determination of ciprofloxacin by the terbium (Ill) ion fluorescence probe sensitized by the surfactant].

The experiments indicated that terbium(III) ion could complex ciprofloxacin, then emitted the characteristic fluorescence of terbium(III) ion. When the surfactant of SDBS was added, the fluorescence intensity of the system was greatly increased. From this, a sensitive method of determining the ciprofloxacin was developted. The fluorescence intensity was determined by a 1 cm quartz cell with the excitation wavelength of 300 nm and the emission wavelength of 545 nm. The optimal conditions are as follows: pH 8.0-8.5, the concentration of terbium(III) is 5.0 x 10(-5) mol x L(-1), the surfactant concentration of SDBS is 8.0 x 10(-4) mol x L(-1). The linear range is 2.5 x 10(-6) mol x L(-1) -2.0 x 10(-8) mol x L(-1), and the detection limit (S/N = 3) is 4.0 x 10(-9) mol x L(-1). The presented method was applied to determine the real pharmaceuticals of ciprofloxacin.

[Determination of ascorbic acid by indirect fluorimetry].

Experiments indicated that cerium(IV) ion which could not emit fluorescence was deoxidized by ascorbic acid to cerium(III) ion which could emit its characteristic fluorescence in water solution, while sodium hexametaphosphate added could greatly enhance the fluorescence intensity of the system. From this, an indirect sensitive method for determining ascorbic acid was developed. The fluorescence intensity of the system was measured in a 1 cm quartz cell with the excitation and emission wavelengths of 303 and 340 nm, respectively. The results showed that the fluorescence intensity of the system presented a linear relationship with the concentration of ascorbic acid in the range of 1.0 x 10(-7)-8.0 x 10(-6) mol x L(-1), the correlation coefficient r was 0.9997, and the detection limit (S/N = 3) was 1.6 x 10(-8) mol x L(-1). The presented method was used to determine ascorbic acid sample and vitamin C tablet, and the results were satisfactory.

[Fluorescence reaction of terbium(III) ion and norepinephrine and its analytical application].

Experiments indicated that terbium(III) ion could form complex with norepinephrine, then emitted its characteristic fluorescence. In the present paper, the fluorescence reaction of terbium(III) ion with norepinephrine was studied in detail. Thus a new method for the determination of norepinephrine was propsed. The fluorescence intensity was measured in a 1 cm quartz cell with the excitation and emission wavelengths of 300 and 545 nm, respectively. The result showed that the fluorescence intensity of the system presented a linear relationship with the concentration of norepinephrine in the range of 0.01-50 microg x mL(-1), and the detection limit (S/N=3) was 1.0 ng x mL(-1). The method was used to determine pharmaceutical sample which contained norepinephrine, and the result was satisfactory.

Interaction of paraquat with calf thymus DNA: a terbium(III) luminescent probe and multispectral study.

Terbium(III), as a good luminescent probe, was developed for the study of the interaction between paraquat and calf thymus DNA (ctDNA) when the binding mode of small molecules to DNA was electrostatic binding. This interaction was further investigated using an ethidium bromide (EB) probe, UV absorption spectra, and circular dichroism spectra. On the basis of Scatchard plots constructed from fluorescence titration data of the ctDNA-Tb(3+) system in the presence of paraquat, the binding constants between paraquat and ctDNA were obtained. The results showed that the electrostatic attraction between positively charged sodium ion and negatively charged phosphate groups could inhibit the binding of paraquat to ctDNA, and competitive inhibition between Tb(3+) and paraquat also existed when they were bound to ctDNA. The effects of paraquat on the fluorescence intensity of the EB-ctDNA system indicated that the intercalation binding of paraquat to ctDNA could be excluded. This conclusion could be further supported by both the absorption spectra of paraquat in the presence of ctDNA and the CD spectra of the paraquat-ctDNA system.

Nitroaniline isomers interaction with bovine serum albumin and toxicological implications.

The interactions of 2-nitroaniline (2-NA), 3-nitroaniline (3-NA) and 4-nitroaniline (4-NA) with bovine serum albumin (BSA) have been investigated by means of fluorescence spectrometry, synchronous fluorescence spectrometry and UV absorption spectrometry under the simulative physiological conditions. Association constants (K(A)) were estimated by the remarkable static quenching effect of 2-NA, 3-NA and 4-NA to the intrinsic fluorescence of BSA, and thermodynamic parameters such as enthalpy change (DeltaH) and entropy change (DeltaS) were calculated according to van't Hoff equation. The results show that hydrophobic force plays a main role in the interaction of nitroanilines to BSA, nitroanilines have high affinity to BSA and the affinity order is as follows: 4-NA > 2-NA > 3-NA. On the basis of this study, it is found that percents of the binding of nitroanilines to BSA are almost no relative to the concentrations of nitroanilines, and correlation between K(A) and logK (ow) is disclosed. In the meantime, relationships between the combination of nitroanilines with BSA and toxicological implications were also discussed. In addition, synchronous fluorescence method was used to study the interaction mechanisms between nitroanilines and BSA, and energy transfer distances from BSA to nitroanilines were estimated based on the Förster's non-radiation energy transfer theory. The results suggest that the binding site for nitroanilines on BSA is close to the sub-domain IIA where Trp 214 is located.

Sensitive determination of norfloxacin by the fluorescence probe of terbium (III)- sodium dodecylbenzene sulfonate and its luminescence mechanism.

The fluorescence system of the norfloxacin-Tb3+- sodium dodecylbenzene sulfonate (SDBS) was investigated in this paper. The experiments indicated that the fluorescence intensity of the Tb3+-SDBS was greatly enhanced by the norfloxacin. On the basis of the above findings, a sensitive fluorimetric method for determining the norfloxacin was established. The fluorescence intensity was measured by a 1-cm quartz cell with the excitation wavelength of 290 nm and the emission wavelength of 545 nm. The enhanced fluorescence intensity of the system (Delta F) showed a good linear relationship with the concentration of norfloxacin in the range of 5.0x10(-9) mol L(-1)-2.0x10(-6) mol L-1, its correlation coefficient was 0.9991 and the detection limit (S/N=3) was 1.2x10(-9) mol L-1. The presented method was used to determine the norfloxacin in real pharmaceutical samples. The luminescence mechanism was also discussed in detail. In the fluorescence system of the norfloxacin-Tb3+-SDBS, the SDBS not only acted as the surfactant, but also acted as the energy donor.