Critical role of checkpoint kinase 1 in spinal cord injury-induced motor dysfunction in mice.

Spinal cord injury (SCI) is a devastating neurotraumatic condition characterized by severe motor dysfunction and paralysis. Accumulating evidence suggests that DNA damage is involved in SCI pathology. However, the underlying mechanisms remain elusive. Although checkpoint kinase 1 (Chk1)-regulated DNA damage is involved in critical cellular processes, its role in SCI regulation remains unclear. This study aimed to explore the role and potential mechanism of Chk1 in SCI-induced motor dysfunction. Adult female C57BL/6J mice subjected to T9-T10 spinal cord contusions were used as models of SCI. Western blotting, immunoprecipitation, histomorphology, and Chk1 knockdown or overexpression achieved by adeno-associated virus were performed to explore the underlying mechanisms. Levels of p-Chk1 and γ-H2AX (a cellular DNA damage marker) were upregulated, while ferroptosis-related protein levels, including glutathione peroxidase 4 (GPX4) and x-CT were downregulated, in the spinal cord and hippocampal tissues of SCI mice. Functional experiments revealed increased Basso Mouse Scale (BMS) scores, indicating that Chk1 downregulation promoted motor function recovery after SCI, whereas Chk1 overexpression aggravated SCI-induced motor dysfunction. In addition, Chk1 downregulation reversed the SCI-increased levels of GPX4 and x-CT expression in the spinal cord and hippocampus, while immunoprecipitation assays revealed strengthened interactions between p-Chk1 and GPX4 in the spinal cord after SCI. Finally, Chk1 downregulation promoted while Chk1 overexpression inhibited NeuN cellular immunoactivity in the spinal cord after SCI, respectively. Collectively, these preliminary results imply that Chk1 is a novel regulator of SCI-induced motor dysfunction, and that interventions targeting Chk1 may represent promising therapeutic targets for neurotraumatic diseases such as SCI.

Hydrogen sulfide ameliorates lipopolysaccharide-induced anxiety-like behavior by inhibiting checkpoint kinase 1 activation in the hippocampus of mice.

Hydrogen sulfide (H2S), an endogenous gasotransmitter, exhibits the anxiolytic roles through its anti-inflammatory effects, although its underlying mechanisms remain largely elusive. Emerging evidence has documented that cell cycle checkpoint kinase 1 (Chk1)-regulated DNA damage plays an important role in the neurodegenerative diseases; however, there are few relevant reports on the research of Chk1 in neuropsychiatric diseases. Here, we aimed to investigate the regulatory role of H2S on Chk1 in lipopolysaccharide (LPS)-induced anxiety-like behavior focusing on inflammasome activation in the hippocampus. Cystathionine γ-lyase (CSE, a H2S-producing enzyme) knockout (CSE-/-) mice displayed anxiety-like behavior and activation of inflammasome-mediated inflammatory responses, manifesting by the increase levels of interleukin-1ß (IL-1ß), IL-6, and ionized calcium-binding adaptor molecule-1 (Iba-1, microglia marker) expression in the hippocampus. Importantly, expression of p-Chk1 and γ-H2AX (DNA damage marker) levels were also increased in the hippocampus of CSE-/- mice. LPS treatment decreased the expression of CSE and CBS while increased p-Chk1 and γ-H2AX levels and inflammasome-activated neuroinflammation in the hippocampus of mice. Moreover, p-Chk1 and γ-H2AX protein levels and cellular immunoactivity were significantly increased while CSE and CBS were markedly decreased in cultured BV2 cells followed by LPS treatment. Treatment of mice with GYY4137, a donor of H2S, inhibited LPS-induced increased in p-Chk1 and γ-H2AX levels, mitigated inflammasome activation and inflammatory responses as well as amelioration of anxiety-like behavior. Notably, SB-218078, a selective Chk1 inhibitor treatment attenuated the effect of LPS on inflammasome activation and inflammatory responses and the induction of anxiety-like behavior. Finally, STAT3 knockdown with AAV-STAT3 shRNA alleviated LPS-induced anxiety-like behavior and inhibited inflammasome activation in the hippocampus, and blockade of NLRP3 with MCC950 attenuated neuroinflammation induction and ameliorated LPS-induced anxiety-like behavior. Overall, this study indicates that downregulation of Chk1 activity by H2S activation may be considered as a valid strategy for preventing the progression of LPS-induced anxiety-like behavior.

Correction to: Comparison of the acute toxicity, analgesic and anti-inflammatory activities and chemical composition changes in Rhizoma anemones Raddeanae caused by vinegar processing.

An amendment to this paper has been published and can be accessed via the original article.

Comparison of the acute toxicity, analgesic and anti-inflammatory activities and chemical composition changes in Rhizoma anemones Raddeanae caused by vinegar processing.

BACKGROUND: As the dry rhizome of Anemone raddeana Regel, Rhizoma Anemones Raddeanae (RAR), which belongs to Ranunculaceae, is usually used to treat wind and cold symptoms, hand-foot disease and spasms, joint pain and ulcer pain in China. It is well known that the efficacy of RAR can be distinctly enhanced by processing with vinegar due to the reduced toxicity and side effects. However, the entry of vinegar into liver channels can cause a series of problems. In this paper, the differences in the acute toxicity, anti-inflammatory and analgesic effects between RAR and vinegar-processed RAR were compared in detail. The changes in the chemical compositions between RAR and vinegar-processed RAR were investigated, and the mechanism of vinegar processing was also explored. METHODS: Acute toxicity experiments were used to examine the toxicity of vinegar-processed RAR. A series of studies, such as the writhing reaction, ear swelling experiment, complete Freund's adjuvant-induced rat foot swelling experiment and cotton granuloma, in experimental mice was conducted to observe the anti-inflammatory effect of vinegar-processed RAR. The inflammatory cytokines of model rats were determined by enzyme-linked immunosorbent assay (ELISA). Liquid Chromatography-Quadrupole-Time of Flight mass spectrometer Detector (LC-Q-TOF) was used to analyse the chemical compositions of the RARs before and after vinegar processing. RESULTS: Neither obvious changes in mice nor death phenomena were observed as the amount of vinegar-processed RAR in crude drug was set at 2.1 g/kg. Vinegar-processed RAR could significantly prolong the latency, reduce the writhing reaction time to reduce the severity of ear swelling and foot swelling, and remarkably inhibit the secretion of Interleukin-1ß(IL-1ß), Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) proinflammatory cytokines. The content of twelve saponins (e.g., Eleutheroside K) in RAR was decreased after vinegar processing, but six other types (e.g., RDA) were increased. CONCLUSIONS: These results revealed that vinegar processing could not only improve the analgesic and anti-inflammatory effects of RAR but also reduce its own toxicity. TRIAL REGISTRATION: Not applicable.

Preparation of carboxylatocalix[4]arene functionalized magnetic polyionic liquid hybrid material for the pre-concentration of phthalate esters.

In this work, we designed a novel hybrid material based on the polymerization of an ionic liquid on a magnetic core and further functionalized with carboxylatocalix[4]arene. Scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscopy, thermal gravimetric-derivative thermogravimetric analysis, energy dispersive X-ray spectroscopy, X-ray diffractometer, and vibrating sample magnetometer were utilized to examine the physicochemical properties of the hybrid material obtained. The material was used as the adsorbent for magnetic solid-phase extraction of phthalate esters. To obtain the maximum pre-concentration efficiency, a series of parameters influencing the extraction efficiency, including sample pH, adsorbent amount, adsorption time, eluent type as well as salt addition, was examined systematically. Under the optimum conditions, a fast and feasible pre-concentration protocol for phthalate esters was established with satisfactory enrichment factors between 158.7 and 191.3. The limits of detection from high-performance liquid chromatographic analysis for the target analytes were in the range of 0.02-0.31 ng mL-1. The wide linear ranges varying from 0.1 to 100 ng mL-1 were achieved with correlation coefficients greater than 0.9977. To evaluate the feasibility of this method, it was successfully applied to analyse phthalate esters in multiple kinds of real samples including tap water, lake water, drinks, tonic lotions, and human serum samples. The results obtained demonstrated that the synthesized magnetic material had potential as a candidate in the pre-concentration field for phthalate esters due to the special properties stemming from its structure and components.

Development of novel magnetic solid phase extraction materials based on Fe3O4/SiO2/poly(acrylamide-N,N'-methylene bisacrylamide)-Pluronic L64 composite microspheres and their application to the enrichment of natamycin.

Novel magnetic adsorbents based on Fe3O4/SiO2/poly(acrylamide-N,N'-methylene bisacrylamide) magnetic microspheres modified with non-ionic triblock copolymer surfactant were successfully prepared as a magnetic solid phase extraction adsorbent for the determination of trace natamycin in jam samples. The adsorbent was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transformed infrared spectroscopy, vibrating sample magnetometer, and X-ray diffractometer analysis, confirming that Pluronic L64 was effectively functionalized on the magnetic materials. Various experimental parameters affecting the extraction capacity were investigated including adsorbent amount, extraction time, desorption time, sample pH, and ionic strength. For recovery evaluations, the jam samples were spiked at two concentration levels of 100 and 200µgkg(-1) of natamycin and the recovery values were in the range of 78.8-93.4%. The relative standard deviations (RSD) for the recoveries were less than 3.5%. The novel magnetic solid phase extraction method provided several advantages, such as simplicity, low environmental impact, convenient extraction procedure, and short analysis time when used for natamycin analysis.

Preconcentration of synthetic phenolic antioxidants by using magnetic zeolites derived with carboxylatocalix[4]arenes combined with high performance liquid chromatography.

Here, we synthesized a novel organic-inorganic hybrid material combining carboxylatocalix[4]arenes and magnetic zeolites by covalent bonding. The complex was characterized by scanning electron microscopy, transmission electron microscopy, Fourier-transformed infrared spectroscopy, X-ray diffraction spectrometry, thermogravimetric analysis/differential thermal gravity analysis, and by using an X-ray photoelectron spectrometer and a vibrating sample magnetometer. The resulting magnetic composite was employed as a solid phase adsorbent to separate and preconcentrate synthetic phenolic antioxidants. Various interactions between the targets and the adsorbent contributed to the adsorption efficiency including hydrophobic interaction, hydrogen-bond interaction, and π-π complexation. The superparamagnetic participation in the process of synthesizing zeolites made the separation process of adsorbent from solutions convenient by an external magnetic field. Taking advantage of this property, this adsorbent could be recycled more than 30 times. The concentrations of the preconcentrated SPAs were determined directly by high-performance liquid chromatography. Various experimental parameters were optimized, according to which the method was evaluated. Finally, the prepared magnetic zeolite@carboxylatocalix[4]arene was successfully applied to identify synthetic phenolic antioxidants from juice and infant milk powder samples with high enrichment factors in the range of 41.9-92.5. The magnetic materials allowed rapid and simple preconcentration, implying their potential in the field of adsorption.