RNAi-mediated knockdown of cyclooxygenase2 inhibits the growth, invasion and migration of SaOS2 human osteosarcoma cells: a case control study

<p>Abstract</p> <p>Background</p> <p>Cyclooxygenase2 (COX-2), one isoform of cyclooxygenase proinflammatory enzymes, is responsible for tumor development, invasion and metastasis. Due to its role and frequent overexpression in a variety of human malignancies, including osteosarcoma, COX-2 has received considerable attention. However, the function of COX-2 in the pathogenesis of cancer is not well understood. We examined the role of COX-2 in osteosarcoma.</p> <p>Methods</p> <p>We employed lentivirus mediated-RNA interference technology to knockdown endogenous gene COX-2 expression in human osteosarcoma cells (SaOS2) and analyzed the phenotypical changes. The effect of COX-2 treatment on the proliferation, cell cycle, invasion and migration of the SaOS2 cells were assessed using the MTT, flow cytometry, invasion and migration assays, respectively. COX-2, vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), basic fibroblast growth factor (bFGF) mRNA and protein expression were detected by RT-PCR and western blotting.</p> <p>Results</p> <p>Our results indicate that a decrease of COX-2 expression in human osteosarcoma cells significantly inhibited the growth, decreased the invasion and migration ability of SaOS2 cells. In addition, it also reduced VEGF, EGF and bFGF mRNA and protein expression.</p> <p>Conclusions</p> <p>The COX-2 signaling pathway may provide a novel therapeutic target for the treatment of human osteosarcoma.</p

Parental migration and cyberbullying victimization among Chinese left-behind children: understanding the association and mediating factors

IntroductionParental absence is greatly associated with school bullying victimization of left-behind children (LBC) in migrant families. With the increasing popularity of the Internet, little is known about the association between parental migration and cyberbullying victimization, and potential mediators.MethodsWe conducted a cross-sectional study in Anhui and Zhejiang Province, China, in 2020. With a sample of 792 currently left-behind children (CLBC), 541 previously left-behind children (PLBC), and 628 never left-behind children (NLBC), path analysis was used to explore the association between parental migration and cyberbullying victimization among children, while considering the independent and sequential mediating roles of parent-child communication, and time spent online.ResultsThe prevalence of cyberbullying victimization was 29.3% among CLBC, 29.2% among PLBC, and 23.4% among NLBC. Path analysis showed that current left-behind status was positively associated with cyberbullying victimization among children (p = 0.024). Furthermore, current left-behind status was associated with worse parent-child communication, which, in turn, predicted a higher prevalence of cyberbullying victimization [95% CI = (0.007, 0.036)]. Similarly, the previous left-behind experience was associated with worse parent-child communication, which, in turn, predicted a higher prevalence of cyberbullying victimization [95% CI = (0.013, 0.043)]. Current left-behind status was associated with increased time spent online, which, in turn, predicted a higher prevalence of cyberbullying victimization [95% CI = (0.013, 0.038)]. Additionally, the current left-behind status positively predicted cyberbullying victimization among children through the serial mediating roles of parent-child communication and time spent online [95% CI = (0.001, 0.006)]. Similarly, previous left-behind experience positively predicted cyberbullying victimization among children through the serial mediating roles of parent-child communication and time spent online [95% CI = (0.002, 0.007)].DiscussionWe propose that to protect CLBC and PLBC from cyberbullying victimization, it is of great importance for migrant parents to regulate children's time spent online and promote daily parent-child communication

The survival of murine hepatitis virus (a surrogate of SARS-CoV-2) on conventional packaging materials under cold chain conditions

IntroductionThe cold chain conditions have been suggested to facilitate long-distance transmission of SARS-CoV-2, but it is unclear how viable the virus is on cold chain packaging materials.MethodsThis study used the MHV-JHM strain of murine hepatitis virus as a model organism to investigate the viability of SARS-CoV-2 on foam, plastic, cardboard, and wood sheets at different temperatures (−40°C, −20°C, and 4°C). In addition, the ability of peracetic acid and sodium hypochlorite to eliminate the MHV-JHM on plastic and cardboard sheets were also evaluated.ResultsThe results indicate that MHV-JHM can survive on foam, plastic, or cardboard sheets for up to 28 days at −40°C and −20°C, and up to 14 days on foam and plastic surfaces at 4°C. Although viral nucleic acids were still detectable after storing at 4°C for 28 days, the corresponding virus titer was below the limit of quantification (LOQ).DiscussionThe study highlights that a positive nucleic acid test result may not indicate that the virus is still viable, and confirms that peracetic acid and sodium hypochlorite can effectively eliminate MHV-JHM on packaging materials under cold chain conditions

Mulberry biomass-derived nanomedicines mitigate colitis through improved inflamed mucosa accumulation and intestinal microenvironment modulation

The therapeutic outcomes of conventional oral medications against ulcerative colitis (UC) are restricted by inefficient drug delivery to the colitis mucosa and weak capacity to modulate the inflammatory microenvironment. Herein, a fluorinated pluronic (FP127) was synthesized and employed to functionalize the surface of mulberry leaf-derived nanoparticles (MLNs) loading with resveratrol nanocrystals (RNs). The obtained FP127@RN-MLNs possessed exosome-like morphologies, desirable particle sizes (around 171.4 nm), and negatively charged surfaces (â 14.8 mV). The introduction of FP127 to RN-MLNs greatly improved their stability in the colon and promoted their mucus infiltration and mucosal penetration capacities due to the unique fluorine effect. These MLNs could efficiently be internalized by colon epithelial cells and macrophages, reconstruct disrupted epithelial barriers, alleviate oxidative stress, provoke macrophage polarization to M2 phenotype, and down-regulate inflammatory responses. Importantly, in vivo studies based on chronic and acute UC mouse models demonstrated that oral administration of chitosan/alginate hydrogel-embedding FP127@RN-MLNs achieved substantially improved therapeutic efficacies compared with nonfluorinated MLNs and a first-line UC drug (dexamethasone), as evidenced by decreased colonic and systemic inflammation, integrated colonic tight junctions, and intestinal microbiota balance. This study brings new insights into the facile construction of a natural, versatile nanoplatform for oral treatment of UC without adverse effects.We are grateful to Dr. J. Sun from University of Oxford for his corrections and improvement of this manuscript. Funding: This study was supported by the National Natural Science Foundation of China (82072060 and 22008201), the Fundamental Research Funds for the Central Universities (SWU-XDPY22006), the Venture & Innovation Support Program for Chongqing Overseas Returnees (2205012980212766), the Natural Science Foundation Project of Chongqing (cstc2020jcyj-msxmX0292), and the Natural Science Foundation Project of Chongqing for Distinguished Young Scholar. Author contributions: W.Y., M.W., X.S., and B.X. designed experiments, supervised the project, and wrote the manuscript draft. W.Y., Y.M., H.X., Z.Z., J.W., C.X., W.S., and E.Z. performed the experiments. R.L.R., S.C.K., M.W., X.S., and B.X. edited and revised the manuscript. All authors have approved the final version of the manuscript. Competing interests: The authors declare that there is no con flict of interest regarding the publication of this article

Nicotine Enhances Staphylococcus epidermidis Biofilm Formation by Altering the Bacterial Autolysis, Extracellular DNA Releasing, and Polysaccharide Intercellular Adhesin Production

Staphylococcus epidermidis is a common bacterial colonizer of human skin and mucous membranes, yet it has emerged as an important nosocomial pathogen largely due to its ability to form biofilms. Tobacco smoke has been demonstrated as a contributor to various infection diseases by improving the biofilm formation of multiple bacterial species; however, the association between tobacco smoke and S. epidermidis biofilm is still unclear. In this study, we tested the effect of nicotine, one of the most active components of tobacco, on S. epidermidis biofilm formation, and we studied the underlying mechanisms. Our results showed that nicotine promoted the biofilm formation of S. epidermidis 1457 strain (SE1457) and enhanced its initial attachment to a polyethylene surface as well as polysaccharide intercellular adhesin (PIA) production. In addition, an increased extracellular DNA release and a higher autolysis rate of SE1457 was detected after nicotine treatment, which was consistent with the increased ratio of dead cells in nicotine-treated SE1457 biofilm observed with confocal laser-scanning microscopy. Furthermore, the effect of nicotine on several autolysis-related and biofilm-related gene knockout mutants of SE1457 was tested. It showed that in ΔsaeRS, ΔlytSR, and ΔsceD, nicotine induced increase in biofilm formation was similar to that in SE1457; but in ΔarlRS, ΔatlE, and ΔicaC, the effect was obviously impaired. Consistently, the increase of the bacterial autolysis rate in ΔarlRS and ΔatlE induced by nicotine was not as significant as that in SE1457. Meanwhile, the growth inhibition of nicotine on SE1457 was observed, and it was much less on ΔarlRS and restored by the arlRS complementation. The arlRS transcription in SE1457 was inhibited by nicotine during cultivation as indicated by a promoter reporter assay using green fluoresent protein. Taken together, our study indicates that nicotine improves S. epidermidis biofilm formation by promoting its initial attachment and intercellular accumulation; the arlRS, atlE, and ica genes mediating bacterial autolysis and PIA production play an important role in this process

Damage evaluation on oil-based drill-in fluids for ultra-deep fractured tight sandstone gas reservoirs

In order to explore the damage mechanisms and improve the method to evaluate and optimize the performance of formation damage control of oil-based drill-in fluids, this paper took an ultra-deep fractured tight gas reservoir in piedmont configuration, located in the Cretaceous Bashijiqike Fm of the Tarim Basin, as an example. First, evaluation experiments were conducted on the filtrate invasion, the dynamic damage of oil-based drill-in fluids and the loading capacity of filter cakes. Meanwhile, the evaluating methods were optimized for the formation damage control effect of oil-based drill-in fluids in laboratory: pre-processing drill-in fluids before grading analysis; using the dynamic damage method to simulate the damage process for evaluating the percentage of regained permeability; and evaluating the loading capacity of filter cakes. The experimental results show that (1) oil phase trapping damage and solid phase invasion are the main formation damage types; (2) the damage degree of filtrate is the strongest on the matrix; and (3) the dynamic damage degree of oil-based drill-in fluids reaches medium strong to strong on fractures and filter cakes show a good sealing capacity for the fractures less than 100 μm. In conclusion, the filter cakes' loading capacity should be first guaranteed, and both percentage of regained permeability and liquid trapping damage degree should be both considered in the oil-based drill-in fluids prepared for those ultra-deep fractured tight sandstone gas reservoirs

The complete chloroplast genome of Chimonobambusa hejiangensis (Poaceae: Arundinarieae) and phylogenetic analysis

Chimonobambusa hejiangensis is a kind of bamboo that has excellent edible and economic value, which is endemic to southwest China. The study used next-generation sequencing to obtain the complete chloroplast (cp) genome sequence of C. hejiangensis. The cp genome of C. hejiangensis has a total length of 138,908 bp, and consisted of an 82,495-bp large single-copy region, an 12,743-bp small single-copy region, and two 21,835-bp IR regions. In total, 112 unique genes were found in the cp genome, including 77 protein coding, 31 tRNA, and 4 rRNA genes. Phylogenetic analysis indicated that C.hejiangensis and C. tumidissinoda are sister species within the Arundinarieae genus, where Chimonocalamus and Ampelocalamus are more closely related to them

Enhanced SO₂ Resistance of Cs-Modified Fe-HZSM-5 for NO Decomposition

Direct decomposition of NO into N2 and O2 is an ideal technology for NOx removal. Catalyst deactivation by sulfur poisoning is the major obstacle for practical application. This paper focuses on strengthening the SO2 resistance of metal-exchanged HZSM-5 catalysts, by investigating the metals, promoters, preparation methods, metal-to-promoter molar ratios, Si/Al ratios and metal loadings. The results show that in the presence of SO2 (500 ppm), Fe is the best compared with Co, Ni and Cu. Cs, Ba and K modification enhanced the low-temperature activity of the Fe-HZSM-5 catalyst for NO decomposition, which can be further improved by increasing the exchanged-solution concentration and Fe/Cs molar ratio or decreasing the Si/Al molar ratio. Interestingly, Cs-doped Fe-HZSM-5 exhibited a high NO conversion and low NO2 selectivity but a high SO2 conversion within 10 h of continuous operation. This indicates that Cs-Fe-HZSM-5 has a relatively high SO2 resistance. Combining the characterization results, including N2 physisorption, XRD, ICP, XRF, UV–Vis, XPS, NO/SO2-TPD, H2-TPR and HAADF-STEM, SO42− was found to be the major sulfur species deposited on the catalyst’s surface. Cs doping inhibited the SO2 adsorption on Fe-HZSM-5, enhanced the Fe dispersion and increased the isolated Fe and Fe-O-Fe species. These findings could be the primary reasons for the high activity and SO2 resistance of Cs-Fe-HZSM-5