Cyr61 is involved in neutrophil infiltration in joints by inducing IL-8 production by fibroblast-like synoviocytes in rheumatoid arthritis

Introduction

It is well known that neutrophils play very important roles in the development of rheumatoid arthritis (RA) and interleukin (IL)-8 is a critical chemokine in promoting neutrophil migration. We previously showed that increased production of Cyr61 by fibroblast-like synoviocytes (FLS) in RA promotes FLS proliferation and Th17 cell differentiation, thus Cyr61 is a pro-inflammatory factor in RA pathogenesis. In this study, we explored the role of Cyr61 in neutrophil migration to the joints of RA patients.

Methods

RA FLS were treated with Cyr61 and IL-8 expression was analyzed by real-time PCR and ELISA. The migration of neutrophils recruited by the culture supernatants was determined by the use of a chemotaxis assay. Mice with collagen-induced arthritis (CIA) were treated with anti-Cyr61 monoclonal antibodies (mAb), or IgG1 as a control. Arthritis severity was determined by visual examination of the paws and joint destruction was determined by hematoxylin-eosin (H&E) staining. Signal transduction pathways in Cyr61-induced IL-8 production were investigated by real-time PCR, western blotting, confocal microscopy, luciferase reporter assay or chromatin immunoprecipitation (ChIP) assay.

Results

We found that Cyr61 induced IL-8 production by RA FLS in an IL-1β and TNF-α independent pathway. Moreover, we identified that Cyr61-induced IL-8-mediated neutrophil migration in vitro. Using a CIA animal model, we found that treatment with anti-Cyr61 mAb led to a reduction in MIP-2 (a counterpart of human IL-8) expression and decrease in neutrophil infiltration, which is consistent with an attenuation of inflammation in vivo. Mechanistically, we showed that Cyr61 induced IL-8 production in FLS via AKT, JNK and ERK1/2-dependent AP-1, C/EBPβ and NF-κB signaling pathways.

Conclusions

Our results here reveal a novel role of Cyr61 in the pathogenesis of RA. It promotes neutrophil infiltration via up-regulation of IL-8 production in FLS. Taken together with our previous work, this study provides further evidence that Cyr61 plays a key role in the vicious cycle formed by the interaction between infiltrating neutrophils, proliferated FLS and activated Th17 cells in the development of RA.     

Variation Characteristics of Chlorpyrifos in Nonsterile Wetland Plant Hydroponic System

Six wetland plants were investigated for their effect on the degradation characteristics of chlorpyrifos in nonsterile hydroponic system at constant temperature of 28°C. The results showed that the removal rates of chlorpyrifos in the water of plant systems were 1.26–5.56% higher than that in the control without plants. Scirpus validus and Typha angustifolia were better than other hygrophytes in elimination of chlorpyrifos. The removal rates of the two systems were up to 88%. Plants of acaulescent group had an advantage over caulescent group in removing chlorpyrifos. Phytoaccumulation of chlorpyrifos was observed, and the order of chlorpyrifos concentration in different plant tissues was root > stem > leaf. It was also found that chlorpyrifos and its metabolite TCP decreased rapidly at the initial step of the experiment.     

Large enhancement of oscillating chemiluminescence with [Ru(bpy)3]2+‐catalyzed Belousov–Zhabotinsky reaction in the presence of tri‐n‐propylamine

Oscillating chemiluminescence enhanced by the addition of tri‐n‐propylamine (TPrA) to the typical Belousov–Zhabotinsky (BZ) reaction system catalyzed by ruthenium(II)tris(2.2'‐bipyridine)(Ru(bpy)₃²⁺) was investigated using a luminometry method. The [Ru(bpy)₃]²⁺/TPrA system was first used as the catalyst for a BZ oscillator in a closed system, which exhibited a shorter induction period, higher amplitude and much more stable chemiluminescence (CL) oscillation. The effects of various concentrations of TPrA, oxygen and nitrogen flow rate on the oscillating behavior of this system were examined. In addition, the CL intensity of the [Ru(bpy)₃]²⁺/TPrA–BZ system was found to be inhibited by phenol, thus providing a way for use of the BZ system in the determination of phenolic compounds. Moreover, the possible mechanism of the oscillating CL reaction catalyzed by [Ru(bpy)₃]²⁺/TPrA and the inhibition effects of oxygen and phenol on this oscillating CL system were considered. Copyright © 2012 John Wiley & Sons, Ltd.     

25-Hydroxyvitamin D3-Loaded PLA Microspheres: In Vitro Characterization and Application in Diabetic Periodontitis Models

This study aimed at the preparation of a sustained-release 25-hydroxyvitamin D₃ (25OHD) treatment for diabetic periodontitis, a known complication of diabetes. 25OHD-loaded polylactic acid (PLA) microspheres were prepared using oil-in-water emulsion–solvent evaporation method. The prepared microspheres exhibited intact surfaces, with average sizes ranging from 42.3 to 119.4 μm. The encapsulation efficiency ranged from 79.2% (w/w) to 88.5% (w/w), and the drug content was between 15.8% (w/w) and 17.8% (w/w). Drug release from the produced microspheres followed a near-to-zero-order release pattern and lasted over 10 weeks. In an in vitro model of diabetic periodontitis, the abnormal morphological changes and the decrease in the cell viability of bone marrow stromal cells could be effectively attenuated after the 25OHD-loaded microsphere application. Additionally, in a rat model of diabetic periodontitis, alveolar bone loss was inhibited and osteoid formation in the periodontium was promoted upon 25OHD-loaded microsphere treatment. In conclusion, 25OHD-loaded PLA microspheres may provide an effective approach for the treatment of this disease.     

Soil Microbial Community Response to Nitrobenzene Exposure for a Spartina Wetland

To explore the response of the soil microbial community to nitrobenzene (NB) exposure in a Spartina marsh, a short-term (45 d) mesocosm study was conducted at three NB concentrations of (10, 50, and 100) mg kg^?1. Dry soil, sterile and unsterile controls were also compared. The ability of the microbes to biodegrade NB was studied in an effort to predict the outcome of NB in the mesocosm. The results indicated that a microbial community is capable of doing so. Microbial enumeration and enzyme assays showed that the fluctuations in microbial communities and polyphenol oxidase activities are related to the initial NB concentration. Moreover, cluster analyses through denaturing gradient gel electrophoresis (DGGE) revealed very similar patterns (95.5%) throughout the 45 d term, indicating that the microbial community regenerates when NB is exhausted. Although volatilization and photolysis were the major processes responsible for the reduction in NB in contaminated mesocosms and the microbial community regenerated at the end of incubation, the data indicate potential ecological risks in outfall areas even if the discharged wastewater complies with the national wastewater discharge standards.     

Fossils from the Middle Jurassic of China shed light on morphology of Choristopsychidae (Insecta,Mecoptera)

Choristopsychidae, established by Martynov in 1937 with a single isolated forewing, is a little known extinct family in Mecoptera. Since then, no new members of this enigmatic family have been described. Based on 23 well-preserved specimens with complete body and wings from the Middle Jurassic of northeastern China, we report one new genus and three new species of Choristopsychidae, two new species of the genus Choristopsyche Martynov, 1937: Choristopsyche perfecta sp. n. and Choristopsyche asticta sp. n.; one new species of Paristopsyche gen. n.: Paristopsyche angelineae sp. n.; and re-describe Choristopsyche tenuinervis Martynov, 1937. In addition, we emend the diagnoses of Choristopsychidae and Choristopsyche. Analyzing the forewing length/width ratios of representative species in Mecoptera, we confirm that choristopsychids have the lowest ratio of forewing length/width, meaning broadest forewings. These findings, the first fossil choristopsychids with well-preserved body structure and the first record of Choristopsychidae in China, shed light on the morphology of these taxa and broaden their distribution from Tajikistan to China, while increasing the diversity of Mesozoic Mecoptera in China.     

Cyclin B1 is an efficacy-predicting biomarker for Chk1 inhibitors

Chk1 is the major mediator of cell-cycle checkpoints in response to various forms of genotoxic stress. Although it was previously speculated that checkpoint abrogation due to Chk1 inhibition may potentiate the efficacy of DNA-damaging agents through induction of mitotic catastrophe, there has not been direct evidence proving this process. Here, through both molecular marker and morphological analysis, we directly demonstrate that specific downregulation of Chk1 expression by Chk1 siRNA potentiates the cytotoxicities of topoisomerase inhibitors through the induction of premature chromosomal condensation and mitotic catastrophe. More importantly, we discovered that the cellular cyclin B1 level is the major determinant of the potentiation. We show that downregulation of cyclin B1 leads to impairment of the induction of mitotic catastrophe and correspondingly a reduction of the potentiation ability of either Chk1 siRNA or a small molecule Chk1 inhibitor. More significantly, we have extended the study by examining a panel of 10 cancer cell-lines with different tissue origins for their endogenous levels of cyclin B1 and the ability of a Chk1 inhibitor to sensitize the cells to DNA-damaging agents. The cellular levels of cyclin B1 positively correlate with the degrees of potentiation achieved. Of additional interest, we observed that the various colon cancer cell lines in general appear to express higher levels of cyclin B1 and also display higher sensitivity to Chk1 inhibitors, implying that Chk1 inhibitor may be more efficacious in treating colon cancers. In summary, we propose that cyclin B1 is a biomarker predictive of the efficacy of Chk1 inhibitors across different types of cancers. Unlike previously established efficacy-predictive biomarkers that are usually the direct targets of the therapeutic agents, cyclin B1 represents a non-drug-target biomarker that is based on the mechanism of action of the target inhibitor. This finding may be potentially very useful for the stratification of patients for Chk1 inhibitor clinical trials and hence, maximize its chance of success.     

Artemisinin induces A549 cell apoptosis dominantly via a reactive oxygen species-mediated amplification activation loop among caspase-9, -8 and -3

This report is designed to explore the roles of caspase-8, -9 and -3 in artemisinin (ARTE)-induced apoptosis in non-small cell lung cancer cells (A549 cells). ARTE induced reactive oxygen species (ROS)-mediated apoptosis in dose- and time-dependent fashion. Although ARTE treatment did not induce Bid cleavage and significant loss of mitochondrial membrane potential, it induced release of Smac and AIF but not cytochrome c from mitochondria, and silencing of Bak but not Bax significantly prevented ARTE-induced cytotoxicity. Moreover, ARTE treatment induced ROS-dependent activation of caspase-9, -8 and -3. Of the utmost importance, silencing or inhibiting any one of caspase-8, -9 and -3 almost completely prevented ARTE-induced activation of all the three caspases and remarkably abrogated the cytotoxicity of ARTE, suggesting that ARTE triggered an amplification activation loop among caspase-9, -8 and -3. Collectively, our data demonstrate that ARTE induces a ROS-mediated amplification activation loop among caspase-9, -8 and -3 to dominantly mediate the apoptosis of A549 cells.     

Enhanced production of (+)-terrein by Aspergillus terreus strain PF26 with epigenetic modifier suberoylanilide hydroxamic acid

New strategies for improving the fermentation yield of (+)-terrein which is a fungal metabolite with multiple bioactivities are very urgent. In this study, the effect of suberoylanilide hydroxamic acid, one kind of epigenetic modifier, on the biosynthesis of (+)-terrein by Aspergillus terreus strain PF26 isolated from the marine sponge Phakellia fusca was investigated. It was found that suberoylanilide hydroxamic acid exhibited a positive impact on (+)-terrein production, resulting from promoting the biosynthesis of 6-hydroxymellein, the precursor of (+)-terrein. Through optimization of feeding concentration and time of suberoylanilide hydroxamic acid, 5.58 g/L (+)-terrein could be obtained in shake flask cultivation, 29.5% higher than the control. Correspondingly, the fermentation of A. terreus strain PF26 in 7.5-L stirred bioreactor with feeding suberoylanilide hydroxamic acid (900 μM, day 4) yielded 9.07 g/L (+)-terrein, 77.1% higher than the control. These results showed that the epigenetic modifier-suberoylanilide hydroxamic acid could be utilized to enhance the production of (+)-terrein, which laid the foundation of massive production of (+)-terrein by fermentation.