Host-specific SRSF7 regulates polymerase activity and replication of influenza A virus.

Avian influenza viruses crossing the host barrier to infect humans have caused great panic in human society and seriously threatened public health. Herein, we revealed that knockdown of SRSF7 significantly down-regulated influenza virus titers and viral protein expression. We further observed for the first time that human SRSF7, but not avian SRSF7, significantly inhibited polymerase activity (PB2627E). Molecular mapping demonstrated that amino acids 206 to 228 of human SRSF7 play a decisive role in regulating the polymerase activity, which contains the amino acid motif absent in avian SRSF7. Importantly, our results illustrated that the PB2627K-encoding influenza virus induces SRSF7 protein degradation more strongly via the lysosome pathway and not via the proteasome pathway. Functional enrichment analysis of SRSF7-related KEGG pathways indicated that SRSF7 is closely related to cell growth and death. Lastly, our results showed that knocking down SRSF7 interferes with normal polymerase activity. Taken together, our results advance our understanding of interspecies transmission and our findings point out new targets for the development of drugs preventing or treating influenza virus infection.

Measurement of Magnesium, Zinc, and Copper in Human Serum by Using Isotope Dilution Inductively Coupled Plasma Mass Spectrometry (ID ICP-MS).

In order to evaluate the reliability of the ID ICP-MS method for the measurement of magnesium, zinc, and copper in human serum, we investigated the traceability, precision, trueness, and uncertainty of the method. This method traces the contents of magnesium, zinc, and copper in human serum to the standard materials NIST SRM3131a, SRM3168a, and SRM3114 respectively, thus completing the traceability to SI unit. The repeatability of this method for measuring magnesium, zinc, and copper in the human serum reference material GBW09152 was found to be 0.2%, 0.7%, and 0.6% (n = 9), respectively. The measurement, when employed to measure the magnesium, zinc, and copper in standard materials, had caused a maximum deviation of less than 0.88%, 1.35%, and 1.15%, respectively. The measurement results are within the stated uncertainty range of standard materials. The expanded uncertainties were 0.2 mg·kg-1, 0.04 mg·kg-1, and 0.08 mg·kg-1 (K = 2) for magnesium, zinc, and copper, respectively. Therefore, this method has high trueness, good reproducibility, and simple operation and is suitable for tracing the values of magnesium, zinc, and copper in human serum.

An influenza virus vector candidate vaccine stably expressing SARS-CoV-2 receptor-binding domain produces high and long-lasting neutralizing antibodies in mice.

Viral infectious pathogens, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza virus, can cause extremely high infection rates and mortality in humans. Therefore, it is urgent to develop an effective vaccine against coronavirus and influenza virus infection. Herein, we used the influenza virus as a vector to express the SARS-CoV-2 spike receptor-binding domain (RBD) and hemagglutinin-esterase-fusion (HEF) protein of the influenza C virus. We then evaluated the feasibility and effectiveness of this design strategy through experiments in vitro and in vivo. The results showed that the chimeric viruses could stably express the HEF protein and the SARS-CoV-2 spike RBD at a high level. BALB/c mice, infected with the chimeric virus, exhibited mild clinical symptoms, yet produced high specific antibody levels against RBD and HEF, including neutralizing antibodies. Importantly, high neutralizing antibodies could be retained in the sera of mice for at least 20 weeks. Altogether, our data provided a new strategy for developing safe and effective COVID-19 and influenza virus vaccines.

Toxoplasma gondii DNA methyltransferases regulate parasitic energy metabolism.

The intracellular protozoan Toxoplasma gondii results in serious diseases such as encephalitis, and retinochoroiditis in immunocompromised patients. The interconversion between tachyzoites and bradyzoites under the host's immune pressure results in the interchange of acute infection and chronic infection. We previously reported two functional DNA methyltransferases (DNMT) in Toxoplasma gondii named TgDNMTa and TgDNMTb. In this research, proteomics analysis for T. gondii tachyzoites of ME49 WT, dnmta knockout (ME49-∆Tgdnmta), and dnmtb knockout (ME49-∆Tgdnmtb) strains, revealed 362 significantly regulated proteins for ME49-∆Tgdnmta, and 219 for ME49-∆Tgdnmtb, compared with the proteins of ME49 WT. TgDNMTa down regulated three glycolytic enzymes, one gluconeogenic enzyme and four pyruvate metabolic enzymes. Furthermore, TgDNMTb up regulated two proteins in the tricarboxylic acid (TCA) cycle. Glucose metabolic flux detection showed that TgDNMTa inhibited the glycolysis pathway, while TgDNMTb promoted the tricarboxylic acid (TCA) cycle so as to promote parasite's proliferation. These findings demonstrated that the functions of Toxoplasma gondii DNA methyltransferases extended beyond DNA methylation to the regulation of parasitic energy metabolism.

Toxoplasma gondii ROP18I inhibits host innate immunity through cGAS-STING signaling.

Toxoplasma gondii is an opportunistic protozoan, which widely infects humans and other warm-blooded animals. The type I interferon (IFN) such as IFN-α/ß is involved in cGAS-STING signaling to resist T. gondii infection. We found in RAW264.7 cells, that T. gondii virulence factor TgROP18I , inhibited IFN-ß production through interacting with interferon regulatory factor 3 (IRF3). Besides, TgROP18I interacted with p62 and Tumor Necrotic Factor Receptor Associated Factor 6 (TRAF6), which resulted in the inhibition of TRAF6-p62 interaction, and phosphorylation of p62. Furthermore, TgROP18I restricted the recruitment of ubiquitin, p62 and microtubule-associated protein light chain 3 (LC3) to the parasitophorous vacuole membrane (PVM) in IFN-γ-stimulated murine cell line L929 cells. In IFN-γ-stimulated human cells, TgROP18I restricted the decoration of PVM with ubiquitin, p62, and LC3, and bound with TRAF2, TRAF6, and p62, respectively. As a result, TgROP18I led to a successful parasitic replication in murine and human cells. Collectively, our study revealed the function of TgROP18I in suppressing host type I interferon responses in T. gondii infection for parasitic immune escape.

Gelatin sponge microparticles for transarterial chemoembolization combined with regorafenib in hepatocellular carcinoma: a single-center retrospective study.

Background: The treatment of advanced hepatocellular carcinoma (HCC) is challenging. The positive effect of gelatin sponge microparticles for transarterial chemoembolization (GSMs-TACE) in the treatment of Barcelona Clinic Liver Cancer (BCLC) stage C and large HCC has been confirmed by previous studies. This study initially explored the efficacy and safety of GSMs-TACE combined with regorafenib in patients with unresectable HCC who failed first-line sorafenib and/or lenvatinib therapy. Methods: This retrospective study collated the data of patients who presented at the Affiliated Zhongshan Hospital of Dalian University between December 2018 and June 2021. Patients were treated with GSMs-TACE, followed by regorafenib 1 week later. Follow-up was conducted every 3 to 5 weeks after combination therapy. If the treatment was changed due to disease progression, the patients were followed up every 3 months to obtain overall survival (OS) time. The OS, progression-free survival (PFS), objective response rate (ORR) and disease control rate (DCR) was used to evaluate the efficacy of the treatment, while adverse events (AEs) was used to assess its safety. Results: A total of 47 patients were included in the study. The age of patients was 64.4±6.8 years; There were 43 (91.5%) males and 4 (8.5%) females; the number of Child-Pugh grade A was 22 (46.8%) and B was 25 (53.2%); the longest tumor diameter was 5.1 cm [interquartile range (IQR), 3.8, 8.9 cm]; the number of BCLC grade B was 14 (29.8%) and grade C was 33 (70.2%). The median follow-up time was 11.6 months [95% confidence interval (CI): 10.8 to 14.0 months]. The median number of GSMS-TACE sessions was 3. The initial doses of regorafenib were 80 mg/d (n=17, 36.2%), 120 mg/d (n=23, 48.9%), and 160 mg/d (n=7, 14.9%). The median PFS was 6.0 months (95% CI: 4.5 to 7.5 months), and the median OS was 14.3 months (95% CI: 11.8 to 16.8 months). The ORR and DCR were 21.3% and 85.1%, respectively. The incidence of grade 3/4 AEs was 8 out of 47 patients (17.0%). Conclusions: The study indicated that GSMs-TACE combined with regorafenib may be efficient and safe in patients with unresectable HCC. Future prospective large-scale studies should be conducted to verify these results.

High-Accuracy Determination of Potassium and Selenium in Human Serum by Two-Step Isotope Dilution ICPMS.

A high-accuracy measurement technique for determining potassium and selenium in human serum was developed by using two-step Isotope Dilution Inductively Coupled Plasma-Mass Spectrometry (ICPMS) in this research. A more accessible method of the quadrupole ICPMS was employed in this research to achieve an equally high accuracy which had been achieved by a much more expensive method, namely, high-resolution sector field ICPMS (SF-ICPMS), with a comparatively easy and simple operation. In addition, we have evaluated the uncertainty of this method. The results showed that the determination limits of potassium and selenium in serum were 0.8 mg/kg and 2.7 µg/kg, respectively, and the precision for both measurements was lower than 0.2% and 0.7%. The measurement, when employed to measure potassium and selenium in standard materials NIST956D, NIST909C, and GBW09152, had caused a maximum deviation of less than 0.9%, within the stated uncertainty range of standard materials. The RELA international inter-laboratory comparisons of potassium in serum in 2018 conducted by our laboratory also yielded a satisfactory result.

Genome-Wide CRISPR Screen Identifies Host Factors Required by Toxoplasma gondii Infection.

Toxoplasma gondii are obligate intracellular protoza, and due to their small genome and limited encoded proteins, they have to exploit host factors for entry, replication, and dissemination. Such host factors can be defined as host dependency factors (HDFs). Though HDFs are inessential for cell viability, they are critical for pathogen infection, and potential ideal targets for therapeutic intervention. However, information about these HDFs required by T. gondii infection is highly deficient. In this study, the genes of human foreskin fibroblast (HFF) cells were comprehensively edited using the lentiviral CRISPR-Cas9-sgRNA library, and then the lentivirus-treated cells were infected with T. gondii at multiplication of infection 1 (MOI = 1) for 10 days to identify HDFs essential for T. gondii infection. The survival cells were harvested and sent for sgRNA sequencing. The sgRNA sequence matched genes or miRNAs were potential HDFs. Some cells in the lentivirus-treated group could survive longer than those in the untreated control group after T. gondii infection. From a pool of 19,050 human genes and 1,864 human pri-miRNAs, 1,193 potential HDFs were identified, including 1,183 genes and 10 pri-miRNAs (corresponding with 17 mature miRNAs). Among them, seven genes and five mature miRNAs were validated with siRNAs, miRNA inhibitors, and mimics, respectively. Bioinformatics analysis revealed that, among the 1,183 genes, 53 potential HDFs were associated with regulation of host actin cytoskeleton and 23 potential HDFs coded immune negative regulators. This result indicated that actin dynamics were indispensable for T. gondii infection, and some host immune negative regulators may be involved in disarming host defenses. Our findings contribute to the current limited knowledge about host factors required by T. gondii infection and provide us with new targets for medication therapy and vaccine exploitation.

Mediastinal hemangioma presenting with a characteristic feature on dynamic computed tomography images.

Hemangiomas are uncommon benign tumors of the mediastinum. The definite diagnosis is sometimes difficult to make because of usually nonspecific features on single-phase contrast-enhanced computed tomography (CT) images. We described a 60-year-old woman suffering from a neck mass with progressive enlargement. On the dynamic CT study, the tumor showed peripheral nodular enhancement on early phase images and progressive centripetal fill-in on delayed phase images. Hemangioma was preoperatively diagnosed on the basis of this characteristic CT appearance.

Diindolilmethane (DIM) selectively inhibits cancer stem cells.

Epidemiologic studies repeatedly have shown chemopreventive effects of cruciferous vegetables. Indole-3-carbinol (I3C) and its metabolite diindolylmethane (DIM) were identified in these plants as active ingredients and theirs anti-tumor activities were confirmed in multiple in vitro and in vivo experiments. Here, we demonstrate that DIM is a selective and potent inhibitor of cancer stem cells (CSCs). In several cancer cell lines, DIM inhibited tumor sphere formation at the concentrations 30-300 times lower than concentrations required for growth inhibition of parental cells cultured as adherent culture. We also found that treatment with DIM overcomes chemoresistance of CSCs to cytotoxics, such as paclitaxel, doxorubicin, and SN-38. Pre-treatment of tumor spheres with DIM before implantation to mice significantly retarded the growth of primary tumors compared to tumors formed by untreated tumor spheres. The concentrations of DIM required to suppress CSCs formation are in the close range to those achievable in human plasma after oral dosing of the compound. Therefore, DIM can potentially be used in cancer patients, either alone, or in combinations with existing drugs.