Migration-inducing gene-7 promotes glioma cell proliferation and invasiveness via activating the MAPK signaling pathway.

Glioma is a highly aggressive primary malignant tumor. Migration-inducing gene-7 (Mig-7) is closely related to tumor invasion and metastasis. However, the detailed molecular mechanism of Mig-7-mediated promotion of glioma cell invasion requires further investigation. Therefore, this study aimed to investigate the molecular mechanism by which Mig-7 promotes invasion and growth of glioma tumor cells. After collecting 65 glioma tissues and 16 non-tumor tissues, the expression difference of Mig-7 between tumor tissues and non-tumor tissues was analyzed. The molecular mechanism of Mig-7 in tumor cells was investigated by knockdown or overexpression of Mig-7 in U87MG cells. Specifically, the expression levels of mitogen-activated protein kinase (MAPK) signaling pathway-related molecules were detected in cells that knocked down Mig-7. MTT, Transwell, and three-dimensional cell culture assays were used to detect the survival, migration, invasion, and tube formation of U87MG cells that overexpressed Mig-7 were treated with the MAPK signaling pathway inhibitors (SP600125, SCH772984, and SB202190). The effect of Mig-7 on the tumorigenic ability of U87MG cells was investigated by subcutaneous tumorigenic experiment in nude mice. The corresponding results indicated that Mig-7 expression was significantly higher in glioma tissues and cell lines compared to that in non-neoplastic brain tissues and normal glial cell lines. In U87MG cells, downregulation or overexpression of Mig-7 inhibited or promoted the expression of MMP-2, MMP-9, LAMC2, EphA2, and VE-cadherin, and phosphorylation levels of ERK1/2, JNK, and p38. Mig-7 overexpression promoted migration, invasion, cell viability, and tube formation, which were reversed by the MAPK signaling pathway inhibitors. Mig-7 overexpression promoted subcutaneous tumor growth in mice and upregulated the phosphorylation levels of ERK1/2, JNK, and p38 and the expression of Ki-67. These effects of Mig-7 overexpression were reversed by MAPK pathway inhibitors. Overall, these results suggest that Mig-7 may be a novel biomarker and potential therapeutic target for glioma, with the MAPK pathway playing a key role in the corresponding Mig-7 mechanism of action.

Aspiration versus stent retriever for posterior circulation stroke: A meta-analysis.

AIMS: New thrombectomy strategies have emerged recently. Differences between posterior circulation stroke management via aspiration and stent retriever remain to be evaluated. We compared the safety and efficacy of aspiration and stent retriever in treating posterior circulation stroke. METHODS: Three databases (PubMed, Embase, and Cochrane Library) were systematically searched for studies comparing aspiration and stent retriever in patients with posterior circulation stroke. The modified Newcastle-Ottawa scale was used to assess the risk of bias. A random-effects model was used. RESULTS: Fifteen cohort studies with 1451 patients were included. Pooled results showed a significant difference in total complication (odds ratio [OR] 0.48, 95% confidence interval [CI] [0.30, 0.76], p = 0.002). successful recanalization (1.85, [1.30, 2.64], p = 0.0006), favorable outcome (1.30, [1.02, 1.67], p = 0.04), procedure duration (-22.10, [-43.32, -0.88], p = 0.04), complete recanalization (4.96, [1.06, 23.16], p = 0.009), and first-pass effect (2.59, [1.55, 4.32], p = 0.0003) between the aspiration and stent retriever groups, and in favor of aspiration. There was no significant difference in the outcomes of rescue therapy (1.42, [0.66, 3.05], p = 0.37) between the two groups. CONCLUSION: Patients with posterior circulation stroke receiving treatment with aspiration achieved better recanalization, first-pass effect, and shorter procedure time. Aspiration may be more secure than a stent retriever.

Recent Advances in Emerging Metal- and Covalent-Organic Frameworks for Enzyme Encapsulation.

Enzyme catalysis enables complex biotransformation to be imitated. This biomimetic approach allows for the application of enzymes in a variety of catalytic processes. Nevertheless, enzymes need to be shielded by a support material under challenging catalytic conditions due to their intricate and delicate structures. Specifically, metal-organic frameworks and covalent-organic frameworks (MOFs and COFs) are increasingly popular for use as enzyme-carrier platforms because of their excellent tunability in structural design as well as remarkable surface modification. These porous organic framework capsules that host enzymes not only protect the enzymes against harsh catalytic conditions but also facilitate the selective diffusion of guest molecules through the carrier. This review summarizes recent progress in MOF-enzyme and COF-enzyme composites and highlights the pore structures tuned for enzyme encapsulation. Furthermore, the critical issues associated with interactions between enzymes and pore apertures on MOF- and COF-enzyme composites are emphasized, and perspectives regarding the development of high-quality MOF and COF capsules are presented.

Electrospun epoxy-based nanofibrous membrane containing biocompatible feather polypeptide for highly stable and active covalent immobilization of lipase.

In this study, a novel poly (glycidyl methacrylate-co-methylacrylate)/feather polypeptide (P(GMA-co-MA)/FP) nanofibrous membrane containing reactive epoxy groups and biocompatible feather polypeptide (FP) was fabricated by electrospinning which was the first time used for the covalent immobilization of lipase. The results of FTIR spectra and SEM images of nanofibrous membrane before and after immobilization demonstrated that lipase has been successfully covalently immobilized on the nanofibrous membrane. FP was beneficial for the stabilization of the enzyme conformation which would promote the improvement of enzyme activity and stability. The P(GMA-co-MA)/FP-Lipase possesses a wide pH tolerance and high thermal stability, good reuse and organic solvent stability. The residual relative activity of immobilized lipase was about 38% which was treated under 70 °C for 3 h. The residual relative activity of immobilized lipase was 62% after 7 reuses and nearly 75% after being treated in methanol for 12 h. This study revealed that the biocompatible FP could be used as an additive to improve the enzyme activity and stability of immobilized enzyme on nanofibrous membranes.

RCA strands as scaffolds to create nanoscale shapes by a few staple strands.

Thousands of nucleotide(nt)-long single strand DNAs, generated from rolling-circle-amplification (RCA), were used as scaffolds to create DNA nanoscale wires and plates with a few short staple strands by following the origami design principle with a crossover at 1.5 turns. The core sequence of the circle template, for producing tens and hundreds of tandemly repeated copies of it by RCA, was designed according to Seeman's sequence design principle for nucleic acid structural engineering (Seeman, N. C. J. Biomol. Struct. Dyn. 1990, 8, 573). The significance for folding the RCA products into nanoscale shapes lies in the design flexibility of both staple and scaffold strand codes, simplicity of a few short staple strands to fold the periodic sequence of RCA products, and lower cost.

DNA microarray fabricated on poly(acrylic acid) brushes-coated porous silicon by in situ rolling circle amplification.

Microarrays hold considerable promise in large-scale biology on account of their analytical, massive and parallel nature. In a step toward further enabling such a capability, we describe the application of rolling circle amplification (RCA) for a sensitive and multiplex detection of nucleic acid targets on oligonucleotide-conjugated polymer brushes covalently grown from porous silicon. Both RCA and polymer brushes have been taken to increase the loading quantity of target molecules and thus improve the detection sensitivity without loss of multiplexing. Besides, polymer brushes were employed to protect porous silicon and to provide biologically simulated environments, making the attached biomolecules maintain bioactivity. This approach can reach a detection limit of 0.1 nM target analytes and three orders of magnitude dynamic range of 0.1-100 nM, with a fluorescence scanner. A two-colour DNA microarray was achieved via RCA of two kinds of circular DNA targets on one chip simultaneously. The porous silicon chip-based RCA technique is promising for the multiplex detection of deoxynucleic acids on microarrays.

Different EDC/NHS activation mechanisms between PAA and PMAA brushes and the following amidation reactions.

Infrared spectroscopy was applied to investigate the well-known EDC/NHS (N-ethyl-N'-(3-(dimethylamino)propyl)carbodiimide/N-hydroxysuccinimide) activation details of poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA) brushes grafted on porous silicon. Succinimidyl ester (NHS-ester) is generally believed to be the dominant intermediate product, conveniently used to immobilize biomolecules containing free primary amino groups via amide linkage. To our surprise, the infrared spectral details revealed that the EDC/NHS activation of PMAA generated anhydride (estimated at around 76% yield and 70% composition), but not NHS-ester (around 5% yield and 11% composition) under the well-documented reaction conditions, as the predominant intermediate product. In contrast, EDC/NHS activation of PAA still follows the general rule, i.e., the expected NHS-ester is the dominant intermediate product (around 45% yield and 57% composition), anhydride the side product (40% yield and 28% composition), under the optimum reaction conditions. The following amidation on PAA-based NHS-esters with a model amine-containing compound, L-leucine methyl ester, generated approximately 70% amides and 30% carboxylates. In contrast, amidation of PAA- or PMAA-based anhydrides with L-leucine methyl ester only produced less than 30% amides but more than 70% carboxylates. The above reaction yields and percentage compositions were estimated by fitting the carbonyl stretching region with 5 possible species, NHS-ester, anhydride, N-acylurea, unreacted acid, unhydrolyzed tert-butyl ester, and using the Beer-Lambert law. The different surface chemistry mechanisms will bring significant effects on the performance of surface chemistry-derived devices such as biochips, biosensors, and biomaterials.

Immunogenicity and protective efficacy in monkeys of purified inactivated Vero-cell SARS vaccine.

BACKGROUND: In 2003, severe acute respiratory syndrome (SARS) resulted in hundreds of infections and deaths globally. We aim to assess immunogenicity and protective efficacy of purified inactivated Vero-cell SARS vaccine in monkeys. METHODS: The cultures of SARS coronavirus (SARS-CoV) BJ-01 strain infected Vero cells were inactivated with beta-propiolactone. Sequential procedures, including ultrafiltration, gel filtration and ion exchange chromatography, were performed to obtain purified inactivated SARS vaccine. The purified SARS vaccine was analyzed with electron microscope, HPLC and Western blotting. We immunized three groups of cynomolgus macaques fascicularis with adjuvant-containing purified vaccine, purified vaccine and unpurified vaccine, respectively, and a fourth group served as a control. Antibody titers were measured by plaque reduction neutralization test. The vaccinated monkeys were challenged with SARS-CoV BJ-01 strain to observe protective efficacy. Additionally, three groups of rhesus monkeys were immunized with different doses of the purified inactivated SARS vaccine (0.5, 1 and 2mug/time/monkey) on days 0 and 7, and the monkeys were challenged with SARS-CoV GZ-01 strain. We assessed the safety of the SARS vaccine and observed whether the antibody dependent enhancement (ADE) occurred under low levels of neutralizing antibody in rhesus. FINDINGS: The purity of SARS vaccine was 97.6% by HPLC identification and reacted with convalescent sera of SARS patients. The purified SARS vaccine induced high levels of neutralizing antibodies and prevented the replication of SARS-CoV in monkeys. Under low levels of neutralizing antibody, no exacerbation of clinical symptoms was observed when the immunized monkeys were challenged with SARS-CoV. In this preliminary animal trial, no side effects were detected when monkeys were immunized with purified SARS vaccine either at normal or large doses. INTERPRETATION: The purified inactivated SARS vaccine could induce high levels of neutralizing antibody, and protect the monkeys from the challenge of SARS-CoV. The SARS vaccine prepared in the study appeared to be safe in monkeys.

Small antisense RNA to cyclin D1 generated by pre-tRNA splicing inhibits growth of human hepatoma cells.

Introns are present in some human pre-tRNAs. They are spliced out during the maturation processes of pre-tRNAs in a way that is irrelevant to their specific nucleotide sequences. This unique characteristic of tRNA splicing can be used for generation of small antisense RNAs by replacing the intron sequences with corresponding antisense sequences. In this work, the intron sequence of human pre-tRNAtyr gene was replaced with a 20 bp antisense sequence targeted to the 5' coding region of cyclin D1, a molecule that was over-expressed in many malignant proliferating cells. Under the control of U6 SnRNA promoter to further enhance transcription efficiency of the modified pre-tRNAtyr gene and subsequent antisense generation, the antisense RNA exhibited obvious suppression of cyclin D1 expression in H22 hepatoma cells. The growth of H22-transplanted tumors in mice was significantly inhibited when treated with naked plasmid DNA harboring the cyclin D1 antisense RNA generating cassette. Such tumor growth inhibition might be due to apoptosis caused by reduced cyclin D1 expression as revealed by immunohistochemical analysis of tumor samples.

Characterization of the 3a protein of SARS-associated coronavirus in infected vero E6 cells and SARS patients.

Proteomics was used to identify a protein encoded by ORF 3a in a SARS-associated coronavirus (SARS-CoV). Immuno-blotting revealed that interchain disulfide bonds might be formed between this protein and the spike protein. ELISA indicated that sera from SARS patients have significant positive reactions with synthesized peptides derived from the 3a protein. These results are concordant with that of a spike protein-derived peptide. A tendency exists for co-mutation between the 3a protein and the spike protein of SARS-CoV isolates, suggesting that the function of the 3a protein correlates with the spike protein. Taken together, the 3a protein might be tightly correlated to the spike protein in the SARS-CoV functions. The 3a protein may serve as a new clinical marker or drug target for SARS treatment.

[Study on the animal model for severe acute respiratory syndrome].

To screen small animals susceptible to SARS-CoV, five species of animals, including guinea pig, hamster, albino hamster, chicken and rat, were experimentally infected with SARS-CoV strain BJ-01 by different routes. On the basis of this, further cynomolgus and rhesus macaques were selected and experimentally inoculated SARS-CoV, the quality they serve as animal model for SARS was evaluated. The results showed that, all five species of small animals chosed were not susceptible to SARS-CoV, no characterized changes in clinical sign and histopathology were observed after infection, but from the lung samples of large rat and pig guinea, the genomic RNA of SARS-CoV could be detected by RT-PCR at day 14 post infection, this suggested that SARS-CoV could replicate in these animals. After inoculated with SARS-CoV, all inoculated cynomolgus and rhesus macaques had developed interstitial pneumonia of differing severity. These changes on histopathology were similar to that seen in SARS patients, but the pathological lesions were less severe than that of human. Except interstitial pneumonia, no other characterized pathological changes were observed. This suggested cynomolgus and rhesus macaques were not the ideal animal model for SARS in fact, but they could serve as animal model for SARS when a more ideal animal model is absent.

[Ultrastructural characteristics of SARS associated virus in infected cells].

OBJECTIVE: Electron microscopical study of infected cells to identify the pathogenic agent of SARS. METHODS: Vero E6 cells infected with lung autopsy samples or nasopharyngeal swabs from SARS patients of Beijing and Guangzhou were inoculated. The supernatant and cultured cells exhibiting identifiable cytopathic effect (CPE) were prepared for electron microscopic study. RESULTS: Examination of CPE cells on thin-section revealed characteristic coronavirus particles within the cisternae of endoplasmic reticulum, Golgi apparatus, vesicles and extracellular space. They were mainly spherical or oval in shape, annular or dense, about 80 nm in diameter. Negative-stain electron microscopy identified coronavirus particles in culture supernatant, 80 - 120 nm in diameter, with club-shaped surface projections. Elongated, rod-, kidney- or other irregular shaped virons with the size of 100 - 200 nm by 60 - 90 nm were also found in the cultured cells infected with the lung samples from the Guangdong patients. Infectious virons entered cells by endocytosis or membrane fusion and released through a budding process. CONCLUSION: These data indicate a novel coronavirus as the causative agent of SARS. Most viral particles showed typical characteristics of coronavirus. The potential role of special shape viruses is expected to be further investigated.

A complete sequence and comparative analysis of a SARS-associated virus (Isolate BJ01).

The genome sequence of the Severe Acute Respiratory Syndrome (SARS)-associated virus provides essential information for the identification of pathogen(s), exploration of etiology and evolution, interpretation of transmission and pathogenesis, development of diagnostics, prevention by future vaccination, and treatment by developing new drugs. We report the complete genome sequence and comparative analysis of an isolate (BJ01) of the coronavirus that has been recognized as a pathogen for SARS. The genome is 29725 nt in size and has 11 ORFs (Open Reading Frames). It is composed of a stable region encoding an RNA-dependent RNA polymerase (composed of 2 ORFs) and a variable region representing 4 CDSs (coding sequences) for viral structural genes (the S, E, M, N proteins) and 5 PUPs (putative uncharacterized proteins). Its gene order is identical to that of other known coronaviruses. The sequence alignment with all known RNA viruses places this virus as a member in the family of Coronaviridae. Thirty putative substitutions have been identified by comparative analysis of the 5 SARS-associated virus genome sequences in GenBank. Fifteen of them lead to possible amino acid changes (non-synonymous mutations) in the proteins. Three amino acid changes, with predicted alteration of physical and chemical features, have been detected in the S protein that is postulated to be involved in the immunoreactions between the virus and its host. Two amino acid changes have been detected in the M protein, which could be related to viral envelope formation. Phylogenetic analysis suggests the possibility of non-human origin of the SARS-associated viruses but provides no evidence that they are man-made. Further efforts should focus on identifying the etiology of the SARS-associated virus and ruling out conclusively the existence of other possible SARS-related pathogen(s).

A genome sequence of novel SARS-CoV isolates: the genotype, GD-Ins29, leads to a hypothesis of viral transmission in South China.

We report a complete genomic sequence of rare isolates (minor genotype) of the SARS-CoV from SARS patients in Guangdong, China, where the first few cases emerged. The most striking discovery from the isolate is an extra 29-nucleotide sequence located at the nucleotide positions between 27,863 and 27,864 (referred to the complete sequence of BJ01) within an overlapped region composed of BGI-PUP5 (BGI-postulated uncharacterized protein 5) and BGI-PUP6 upstream of the N (nucleocapsid) protein. The discovery of this minor genotype, GD-Ins29, suggests a significant genetic event and differentiates it from the previously reported genotype, the dominant form among all sequenced SARS-CoV isolates. A 17-nt segment of this extra sequence is identical to a segment of the same size in two human mRNA sequences that may interfere with viral replication and transcription in the cytosol of the infected cells. It provides a new avenue for the exploration of the virus-host interaction in viral evolution, host pathogenesis, and vaccine development.

Complete genome sequences of the SARS-CoV: the BJ Group (Isolates BJ01-BJ04).

Beijing has been one of the epicenters attacked most severely by the SARS-CoV (severe acute respiratory syndrome-associated coronavirus) since the first patient was diagnosed in one of the city's hospitals. We now report complete genome sequences of the BJ Group, including four isolates (Isolates BJ01, BJ02, BJ03, and BJ04) of the SARS-CoV. It is remarkable that all members of the BJ Group share a common haplotype, consisting of seven loci that differentiate the group from other isolates published to date. Among 42 substitutions uniquely identified from the BJ group, 32 are non-synonymous changes at the amino acid level. Rooted phylogenetic trees, proposed on the basis of haplotypes and other sequence variations of SARS-CoV isolates from Canada, USA, Singapore, and China, gave rise to different paradigms but positioned the BJ Group, together with the newly discovered GD01 (GD-Ins29) in the same clade, followed by the H-U Group (from Hong Kong to USA) and the H-T Group (from Hong Kong to Toronto), leaving the SP Group (Singapore) more distant. This result appears to suggest a possible transmission path from Guangdong to Beijing/Hong Kong, then to other countries and regions.