ARIH1 inhibits influenza A virus replication and facilitates RIG-I dependent immune signaling by interacting with SQSTM1/p62.

BACKGROUND: Multiple host factors are involved in modulating type I interferon expression induced by viruses; however, the mechanism is not fully elucidated. Influenza A virus infection causes severe respiratory symptoms and triggers a series of signaling cascades and host innate immune responses, including interferon production. The co-IP/MS technology was used to screen several antiviral factors in the early stage. Among these factors, ariadne-1 homolog (ARIH1) caught our attention. METHODS: Western blot assay was performed to detect the level of proteins and software ImageJ was used to analyze the band intensities. Polymerase activity assay was conducted to evaluate the polymerase activity of influenza A virus. Tissue culture infective dose (TCID50) assay was performed to measure influenza A virus titers, and quantitative RT-PCR assay was applied to test the mRNA level of IFN-ß, ISG56, and CXCL10. Luciferase reporter assay was used to confirm the target of ARIH1 in RIG-I signaling. Immunoprecipitation assay was performed to detect the interaction and the ubiquitination of the proteins. All data were analyzed by biostatistical methods and presented as means ± standard deviation from three independent experiments. Statistical significance was determined using two-tailed student's t test. A P value of less than 0.05 was considered statistically significant, and a P value of less than 0.01 was considered highly significant (ns, P ≥ 0.05; *, P < 0.05; and **, P < 0.01). RESULTS: We found that ARIH1, a member of E3 ubiquitin ligases, enhanced cellular antiviral responses. Subsequent study showed that ARIH1 was up-regulated during influenza A virus infection. Further analysis showed that ARIH1 enhanced IFN-ß and downstream gene expression by affecting the degradation of RIG-I through the SQSTM1/p62 signaling pathway. CONCLUSION: This newly revealed mechanism shows that cellular response increases of ARIH1 and promotes IFN-ß expression to boost host survival during viral infection.

Urolithin A inhibits enterovirus 71 replication and promotes autophagy and apoptosis of infected cells in vitro.

Hand, foot, and mouth disease (HFMD) is a serious threat to the health of infants, and it can be caused by enterovirus 71 (EV71). The clinical symptoms are mostly self-limiting, but some infections develop into aseptic meningitis with poor prognosis and even death. In this study, urolithin A (UroA), an intestinal metabolite of ellagic acid, significantly inhibited the replication of EV71 in cells. Further evaluation showed that UroA was better than ribavirin in terms of its 50% cytopathic concentration (CC50), 50% inhibitory concentration (IC50), and selectivity index. Moreover, UroA inhibited the proliferation of EV71 by promoting autophagy and apoptosis of infected cells. Therefore, UroA is a candidate drug for the treatment of EV71 infection.

One-pot synthesis of a PtPd dendritic nanocube cage superstructure on graphenes as advanced catalysts for oxygen reduction.

How to use Pt economically and efficiently in the oxygen reduction reaction (ORR) is of theoretical and practical significance for the industrialization of the proton-exchange membrane fuel cells. In order to minimize Pt consumption and optimize the ORR performance, the ORR catalysts are recommended to be designed as a porous nanostructure. Herein, we report a one-pot solvothermal strategy to prepare PtPd dendritic nanocube cages via a galvanic replacement mechanism triggered by an I- ion. These PtPd alloy crystals are nanoporous, and uniformly dispersed on reduced graphene oxides (RGOs). The size of the PtPd dendritic nanocube cages can be easily tuned from 20-80 nm by controlling their composition. Their composition is optimized to be 1:5 Pt/Pd atomic ratio for these RGO-supported PtPd dendritic nanocages. This catalyst shows superior ORR performance with a specific activity of 2.01 mA  cm-2 and a mass activity of 4.45 A  mg-1 Pt, far above those for Pt/C catalysts (0.288 mA  cm-2 for specific activity, and 0.21 A  mg-1 Pt for mass activity). In addition to ORR activity, it also exhibits robust durability with almost negligible decay in ORR mass activity after 10 000 voltammetric cycling.

Accurate comparison of antibody expression levels by reproducible transgene targeting in engineered recombination-competent CHO cells.

Over the years, Chinese hamster ovary (CHO) cells have emerged as the major host for expressing biotherapeutic proteins. Traditional methods to generate high-producer cell lines rely on random integration(s) of the gene of interest but have thereby left the identification of bottlenecks as a challenging task. For comparison of different producer cell lines derived from various transfections, a system that provides control over transgene expression behavior is highly needed. This motivated us to develop a novel "DUKX-B11 F3/F" cell line to target different single-chain antibody fragments into the same chromosomal target site by recombinase-mediated cassette exchange (RMCE) using the flippase (FLP)/FLP recognition target (FRT) system. The RMCE-competent cell line contains a gfp reporter fused to a positive/negative selection system flanked by heterospecific FRT (F) variants under control of an external CMV promoter, constructed as "promoter trap". The expression stability and FLP accessibility of the tagged locus was demonstrated by successive rounds of RMCE. As a proof of concept, we performed RMCE using cassettes encoding two different anti-HIV single-chain Fc fragments, 3D6scFv-Fc and 2F5scFv-Fc. Both targeted integrations yielded homogenous cell populations with comparable intracellular product contents and messenger RNA (mRNA) levels but product related differences in specific productivities. These studies confirm the potential of the newly available "DUKX-B11 F3/F" cell line to guide different transgenes into identical transcriptional control regions by RMCE and thereby generate clones with comparable amounts of transgene mRNA. This new host is a prerequisite for cell biology studies of independent transfections and transgenes.

Study on Adenovirus Infection in vitro with Nanoself-Assembling Peptide as Scaffolds for 3D Culture.

PURPOSE: To construct a three-dimensional (3D) culture model of adenovirus in vitro using the nanoself-assembling peptide RADA16-I as a 3D cell culture scaffold combined with virology experimental technology to provide a novel research method for virus isolation and culture, pathogenesis research, antiviral drug screening and vaccine preparation. METHODS: The nanoself-assembling peptide RADA16-I was used as a 3D scaffold material for 293T cell culture, and adenovirus was cultured in the cells. The growth, morphological characteristics and pathological effects of 3D-cultured 293T cells after adenovirus infection were observed with an inverted microscope and MTS. The proliferation of adenovirus in 293T cells was observed by TEM and detected by qPCR. The levels of TNF-α and IL-8 secreted by adenovirus-infected 293T cells in the RADA16-I 3D culture system were detected by ELISA. RESULTS: The 293T cells grew well in the RADA16-I 3D culture system for a prolonged period of time. The adenovirus infection persisted for a long time with multiple proliferation peaks, which closely resembled those of in vivo infections. The adenovirus virions amplified in the 3D system remained infectious. There were multiple secretion peaks of TNF-α and IL-8 secretion levels in adenovirus-infected 293T cells cultured in 3D culture systems. CONCLUSION: The nanoself-assembling peptide RADA16-I can be used as a 3D scaffold for adenovirus isolation, culture and research. The 3D culture system shows more realistic in vivo effects than two-dimensional (2D) culture.

Acute and repeated dose 26-week oral toxicity study of 20(S)-ginsenoside Rg3 in Kunming mice and Sprague-Dawley rats.

BACKGROUND: 20(S)-ginsenoside-Rg3 (C42H72O13), a natural triterpenoid saponin, is extracted from red ginseng. The increasing use of 20(S)-ginsenoside Rg3 has raised product safety concerns. METHODS: In acute toxicity, 20(S)-ginsenoside Rg3 was singly and orally administrated to Kunming mice and Sprague-Dawley (SD) rats at the maximum doses of 1600 mg/kg and 800 mg/kg, respectively. In the 26-week toxicity study, we used repeated oral administration of 20(S)-ginsenoside Rg3 in SD rats over 26 weeks at doses of 0, 20, 60, or 180 mg/kg. Moreover, a 4-week recovery period was scheduled to observe the persistence, delayed occurrence, and reversibility of toxic effects. RESULTS: The result of acute toxicity shows that oral administration of 20(S)-ginsenoside Rg3 to mice and rats did not induce mortality or toxicity up to 1600 and 800 mg/kg, respectively. During a 26-week administration period and a 4-week withdrawal period (recovery period), there were no significant differences in clinical signs, body weight, food consumption, urinalysis parameters, biochemical and hematological values, or histopathological findings. CONCLUSION: The mean oral lethal dose (LD50) of 20(S)-ginsenoside Rg3, in acute toxicity, is above 1600 mg/kg and 800 mg/kg in mice and rats, respectively. In a repeated-dose 26-week oral toxicity study, the no-observed-adverse-effect level for female and male SD rats was 180 mg/kg.

[Three cases of pulmonary alveolar microlithiasis in a family and clinical analysis].

OBJECTIVE: To describe the characteristics of 3 cases of pulmonary alveolar microlithiasis in a family, and therefore to improve the understanding of the disease. METHODS: To analyze the clinical, laboratory and radiological data of three patients with pulmonary alveolar microlithiasis in a family and the relevant literatures were reviewed. RESULTS: There was a typical manifestation in these three cases of pulmonary alveolar microlithiasis: progressive dyspnoea, cough, family history. Chest X-ray and computed tomography demonstrate: the pulmones was full of high density reflection of intra-alveolar microliths especially in middle-lower lobe and posterior lobe. The etiology of these three cases is still unknown, consanguineous marriage of parents is possible reason. There was not effective therapies to them. CONCLUSION: Pulmonary alveolar microlithiasis is a disease without clear known etiology and effective therapy. For a patient with radiological features of high density intra-alveolar microliths and a positive family history, the diagnosis should be highly suspected.

[Detection of SLC34A2 in patients with pulmonary alveolar microlithiasis and the effect of SLC34A2 on transportation of calcium and phosphate in human alveolar epithelial cells].

OBJECTIVE: To detect the mutation of SLC34A2 in patients with pulmonary alveolar microlithiasis and to study the effect of SLC34A2 on transportation of calcium and phosphate in human alveolar epithelial cell (A549) cells. METHODS: The gene SLC34A2 was detected by segmentation-PCR and gene sequencing. RNA was obtained by Trizol from fresh lung tissues and the target gene was acquired by RT-PCR. Eukaryotic expression of recombinant pcDNA3.1(+)-SLC34A2 was constructed and SLC34A2 was transfected to A549 cells by liposome. The expression of SLC34A2 mRNA was detected by RT-PCR, and the content of calcium and phosphate of the extracellular fluid was measured by commercial kits. The cell experiments consisted of 3 groups including a control group (5 x 10(5)/well, one well), a blank group (5 x 10(5)/well, one well), a transfection group (5 x 10(5)/well, four wells). Every experiment was repeated 6 times. RESULTS: No mutation was found in patients with pulmonary alveolar microlithiasis. SLC34A2 cDNA was successfully amplified and the eukaryotic expression recombinant pcDNA3.1(+)-SLC34A2 was successfully constructed. The amount of SLC34A2 mRNA of the transfected cells was significantly higher (2.48 +/- 0.45), compared to the control cells (0.55 +/- 0.07) and the blank cells (0.60 +/- 0.06), q = 16.25, 15.78, all P < 0.01. The content of calcium and phosphate in the supernatant of the transfected cells was lower [(0.110 +/- 0.016) mmol/L, (3.8 +/- 0.4) mmol/L], compared with the control [(0.254 +/- 0.047) mmol/L, (7.3 +/- 0.8) mmol/L] and the blank (0.262 +/- 0.041) mmol/L, (7.1 +/- 0.4) mmol/L], q = 8.657 - 13.892, all P < 0.01. CONCLUSIONS: In human lung alveolar epithelial cells, the content of calcium and phosphate in cell supernatant decreased with increased amount of SLC34A2 mRNA. Mutation of SLC34A2 may not be at the DNA level.

Expanding Flp-RMCE options: the potential of Recombinase Mediated Twin-Site Targeting (RMTT).

Where possible, developments enabling the establishment of cell lines with predictable, long-term stable expression capacity are based on single-copy integrations at safe genomic loci with predictable properties. Robust performance could be assigned to lentiviral transduction systems anchoring single LV-units at sites with adequate transcription potential. In the case of gene therapeutic vectors it is essential that the expression interval can be safely terminated following individual requirements, which has mostly been achieved by lox-mediated excision ("floxing"). To extend the spectrum of possible applications we replaced the common, phage-derived Cre/loxP-setup by modules derived from the yeast "Flp/FRT" site-specific recombination system. This change enables a variety of additional options, for instance by "multiplexing" strategies, which rely on a variety of heterospecific FRT-site variants (F'). If we provide lentiviral LTRs with a "twin-site", here an FF3 fusion, the presence of Flp-recombinase will effectively excise the expression cassette, leaving behind a single neutral, genomically anchored FF3 unit. This tag serves to identify the integration locus and to apply sequence- and structural (SIDD-) analyses to predict its functions. Candidate loci are then used to accommodate, at the given site, other genes of interest by "Recombinase-Mediated Twin Site Targeting" (RMTT), a contemporary extension of existing cassette exchange (RMCE-) routines. Supported by the fact that FF3 twins remain accessible within the host genome, RMTT provides access to certified cell lines as it complies with recently defined stringent genomic safe harbor criteria. Our discussion- and outlook-sections will cover lentiviral targeting strategies and current possibilities to enable their fine-tuning.

Recombinase-mediated cassette exchange (RMCE) - a rapidly-expanding toolbox for targeted genomic modifications.

Starting in 1991, the advance of Tyr-recombinases Flp and Cre enabled superior strategies for the predictable insertion of transgenes into compatible target sites of mammalian cells. Early approaches suffered from the reversibility of integration routes and the fact that co-introduction of prokaryotic vector parts triggered uncontrolled heterochromatization. Shortcomings of this kind were overcome when Flp-Recombinase Mediated Cassette Exchange entered the field in 1994. RMCE enables enhanced tag-and-exchange strategies by precisely replacing a genomic target cassette by a compatible donor construct. After "gene swapping" the donor cassette is safely locked in, but can nevertheless be re-mobilized in case other compatible donor cassettes are provided ("serial RMCE"). These features considerably expand the options for systematic, stepwise genome modifications. The first decade was dominated by the systematic generation of cell lines for biotechnological purposes. Based on the reproducible expression capacity of the resulting strains, a comprehensive toolbox emerged to serve a multitude of purposes, which constitute the first part of this review. The concept per se did not, however, provide access to high-producer strains able to outcompete industrial multiple-copy cell lines. This fact gave rise to systematic improvements, among these certain accumulative site-specific integration pathways. The exceptional value of RMCE emerged after its entry into the stem cell field, where it started to contribute to the generation of induced pluripotent stem (iPS-) cells and their subsequent differentiation yielding a variety of cell types for diagnostic and therapeutic purposes. This topic firmly relies on the strategies developed in the first decade and can be seen as the major ambition of the present article. In this context an unanticipated, potent property of serial Flp-RMCE setups concerns the potential to re-open loci that have served to establish the iPS status before the site underwent the obligatory silencing process. Other relevant options relate to the introduction of composite Flp-recognition target sites ("heterospecific FRT-doublets"), into the LTRs of lentiviral vectors. These "twin sites" enhance the safety of iPS re-programming and -differentiation as they enable the subsequent quantitative excision of a transgene, leaving behind a single "FRT-twin". Such a strategy combines the established expression potential of the common retro- and lentiviral systems with options to terminate the process at will. The remaining genomic tag serves to identify and characterize the insertion site with the goal to identify genomic "safe harbors" (GOIs) for re-use. This is enabled by the capacity of "FRT-twins" to accommodate any incoming RMCE-donor cassette with a compatible design.

Recombinase-mediated cassette exchange (RMCE): traditional concepts and current challenges.

Traditional DNA transduction routes used for the modification of cellular genomes are subject to unpredictable alterations, as the cell-intrinsic repair machinery may affect both the integrity of the transgene and the recipient locus. These problems are overcome by recombinase-mediated cassette exchange (RMCE) approaches enabling predictable expression patterns by the nondisruptive insertion of a gene cassette at a pre-characterized genomic locus. The destination is marked by a "tag" consisting of two heterospecific recombination target sites (RTs) at the flanks of a selection marker. Provided on a circular donor vector, an analogous cassette encoding the gene of interest can cleanly replace the resident cassette under the influence of a site-specific recombinase. RMCE was first based on the yeast integrase Flp but had to give way to the originally more active phage-derived Cre enzyme. To be effective, both Tyr-recombinases have to be applied at a considerable concentration, which, in the case of Cre, triggers endonucleolytic activities and therefore cellular toxicity. This review addresses the particularities of both recombination routes depending on the structure of the synaptic complex and on improved integrase and RT variants. While the performance of Flp-RMCE can now firmly rely on optimized Flp variants and multiple sets of functional target sites (FRTs), the Cre system suffers from the promiscuity of its RT mutants, which is explained in molecular terms. At present, RMCE enters applications in the stem cell field. Remarkable efforts are noted in the framework of various mouse mutagenesis programs, which, in their first phase, have targeted virtually all genes and now start to shift their emphasis from gene trapping to gene modification.

Novel tag-and-exchange (RMCE) strategies generate master cell clones with predictable and stable transgene expression properties.

Site-specific recombinases have revolutionized the systematic generation of transgenic cell lines and embryonic stem cells/animals and will ultimately also reveal their potential in the genetic modification of induced pluripotent stem cells. Introduced in 1994, our Flp recombinase-mediated cassette exchange strategy permits the exchange of a target cassette for a cassette with the gene of interest, introduced as a part of an exchange vector. The process is "clean" in the sense that it does not co-introduce prokaryotic vector parts; neither does it leave behind a selection marker. Stringent selection principles provide master cell lines permitting subsequent recombinase-mediated cassette exchange cycles in the absence of a drug selection and with a considerable efficiency (approximately 10%). Exemplified by Chinese hamster ovary cells, the strategy proves to be successful even for cell lines with an unstable genotype.

PARP-1 expression in the mouse is controlled by an autoregulatory loop: PARP-1 binding to an upstream S/MAR element and to a novel recognition motif in its promoter suppresses transcription.

This work identifies central components of a feedback mechanism for the expression of mouse poly(ADP-ribose) polymerase-1 (PARP-1). Using the stress-induced duplex destabilization algorithm, multiple base-unpairing regions (BURs) could be localized in the 5' region of the mouse PARP-1 gene (muPARP-1). Some of these could be identified as scaffold/matrix-attachment regions (S/MARs), suggesting an S/MAR-mediated transcriptional regulation. PARP-1 binding to the most proximal element, S/MAR 1, and to three consensus motifs, AGGCC, in its own promoter (basepairs -956 to +100), could be traced by electrophoretic mobility-shift assay. The AGGCC-complementary GGCCT motif was detected by cis-diammine-dichloro platinum cross-linking and functionally characterized by the effects of site-directed mutagenesis on its performance in wild type (PARP-1(+/+)) and PARP-1 knockout cells (PARP-1(-/-)). Mutation of the central AGGCC tract at basepairs -554 to -550 prevented PARP-1/promoter interactions, whereby muPARP-1 expression became up-regulated. Transfection of a series of reporter gene constructs with or without S/MAR 1 (basepairs -1523 to -1007) and the more distant S/MAR 2 (basepairs -8373 to -6880), into PARP-1(+/+) as well as PARP-1(-/-) cells, revealed an additional, major level of muPARP-1 promoter down-regulation, triggered by PARP-1 binding to S/MAR 1. We conclude that S/MAR 1 represents an upstream control element that acts in conjunction with the muPARP-1 promoter. These interactions are part of a negative autoregulatory loop.

[Preparation and identification of monoclonal antibodies against human DcR3].

AIM: To prepare monoclonal antibodies(mAbs) against human DcR3 and identify their characterization. METHODS: BALB/c mice were immunized with purified His-DcR3 protein, and mAbs against DcR3 which prepared by hybridoma technique were purified and identified by their specificity, subtype, titers via ELISA and Western blot. RESULTS: Five hybridoma cell lines secreting mAbs against human DcR3 were obtained, which were determined as IgG1 subtype and ascites titers of five mAbs against DcR3 reached 1x10(-5)-1x10(-7). Five mAbs were proved to recognize His-DcR3 protein specifically, one of which (1B1) could recognize SW480 cell. CONCLUSION: mAbs against DcR3 with high titers and specificity have been prepared and purified successfully, which laid a foundation for the study of DcR3 expression, distribution in tissu and development of ELISA kit.

Recommended Method for Chromosome Exploitation: RMCE-based Cassette-exchange Systems in Animal Cell Biotechnology.

The availability of site-specific recombinases has revolutionized the rational construction of cell lines with predictable properties. Early efforts were directed to providing pre-characterized genomic loci with a single recombinase target site that served as an address for the integration of vectors carrying a compatible tag. Efficient procedures of this type had to await recombinases like PhiC31, which recombine attP and attB target sites in a one-way reaction - at least in the cellular environment of the higher eukaryotic cell. Still these procedures lead to the co-introduction of prokaryotic vector sequences that are known to cause epigenetic silencing. This review illuminates the actual status of the more advanced recombinase-mediated cassette exchange (RMCE) techniques that have been developed for the major members of site-specific recombinases (SR), Flp, Cre and PhiC31. In RMCE the genomic address consists of a set of heterospecific recombinase target (RT-) sites permitting the exchange of the intervening sequence for the gene of interest (GOI), as part of a similar cassette. This process locks the GOI in place and it is 'clean' in the sense that it does not co-introduce prokaryotic vector parts nor does it leave behind a selection marker.