Immunological Study of Reconstructed Common Ancestral Sequence of Adenovirus Hexon Protein.

Aim: To reconstruct the ancestral sequence of human adenoviral hexon protein by combining sequence variations and structural information. And to provide a candidate hexon protein for developing new adenoviral vector capable of escaping the pre-existing immunity in healthy populations. Methods: The sequences of 74 adenovirus-type strains were used to predict the ancestral sequence of human adenovirus hexon protein using FastML and MEGA software. The three-dimensional structure model was built using homology modeling methods. The immunological features of ancestral loop 1 and loop 2 regions of sequences were tested using protein segments expressed in a prokaryotic expression system and polypeptides synthesized with human serum samples. Results: The tower region of the hexon protein had the highest sequence variability, while the neck and base regions remained constant among different types. The modern strains successfully predicted the common ancestral sequence of the human adenovirus hexon. The positive sera against neutralizing epitopes on the common ancestor of adenoviral hexon were relatively rare among healthy adults. Conclusion: The existing strains inferred the common ancestor of human adenoviruses, with epitopes never observed in the current human strains. The predicted common ancestor hexon is a good prospect in the improvement of adenovirus vectors.

Prevalence of Common Respiratory Viral Infections and Identification of Adenovirus in Hospitalized Adults in Harbin, China 2014 to 2017.

Background: Respiratory infections pose a great challenge in global health, and the prevalence of viral infection in adult patients has been poorly understood in northeast China. Harbin is one of the major cities in northeast China, and more than half of any given year in Harbin is occupied by winter. To reveal the viral etiology and seasonality in adult patients from Harbin, a 4-year consecutive survey was conducted in Harbin, China. Methods: From January 2014 to December 2017, specimens were obtained from adult patients admitted to the Second Affiliated Hospital of Harbin Medical University with lower respiratory tract infections. Sputum samples were examined by direct immunofluorescence assays to detect seven common respiratory viruses, including influenza virus (type A and B), parainfluenza virus (type 1 to 3), respiratory syncytial virus and adenovirus. Adenovirus positive samples were seeded onto A549 cells to isolate viral strains. Phylogenetic analysis was conducted on the highly variable region of adenoviral hexon gene. Results: A total of 1,300 hospitalized adult patients with lower respiratory tract infections were enrolled, in which 189 patients (14.5%) were detected as having at least one viral infection. The co-infection rate in this study was 25.9% (49/189). The dominant viral pathogen from 2014 to 2017 was parainfluenza virus, with a detection rate of 7.2%, followed by influenza virus, respiratory syncytial virus and adenovirus. Based on the climate seasons determined by daily average temperature, the highest overall viral detection rate was detected in spring (22.0%, 52/236), followed by winter (13.4%, 109/813), autumn (11.4%, 13/114) and summer (10.9%, 15/137). Adenovirus type 3 strains with slight variations were isolated from positive cases, which were closely related to the GB strain from the United States, as well as the Harbin04B strain isolated locally. Conclusion: This study demonstrated that common respiratory viruses were partially responsible for hospitalized lower respiratory tract infections in adult patients from Harbin, China, with parainfluenza virus as the dominant viral pathogen. Climate seasons could be rational indicators for the seasonality analysis of airborne viral infections. Future surveillance on viral mutations would be necessary to reveal the evolutionary history of respiratory viruses.

γ-Tocotrienol inhibits angiogenesis of human umbilical vein endothelial cell induced by cancer cell.

Antiangiogenic therapy mediated by food components is an established strategy for cancer chemoprevention. Growth factors play critical roles in tumor angiogenesis. A conditioned medium containing growth factors from human gastric adenocarcinoma SGC-7901 cell conditioned medium was used as an angiogenic stimulus in this study. The purpose of this study was to evaluate the inhibitory effect and possible mechanism of γ-tocotrienol on tumor angiogenesis. The results showed that γ-tocotrienol (10-40 µmol/L) significantly suppressed proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs) induced by SGC-7901 cell conditioned medium in a dose-dependent manner. γ-Tocotrienol (800-1200 µg/egg) also inhibited new blood vessel formation on the growing chick embryo chorioallantoic membrane in a dose-dependent manner. Moreover, the inhibitory effects of γ-tocotrienol on HUVECs were correlated with inducing the apoptosis and arresting cell cycle at the G(0)/G(1) phase at a dose of 40 µmol/L γ-tocotrienol. In addition, γ-tocotrienol inhibited angiogenesis in HUVECs by down-regulation of ß-catenin, cyclin D1, CD44, phospho-VEGFR-2 and MMP-9. The antiangiogenic effects of γ-tocotrienol on HUVECs may be attributable to regulation of Wnt signaling by decreasing ß-catenin expression. Thus, our results suggest that γ-tocotrienol has a potential chemopreventive agent via antiangiogenesis.

Inhibition of proliferation and induction of apoptosis by gamma-tocotrienol in human colon carcinoma HT-29 cells.

OBJECTIVE: gamma-Tocotrienol is a major component of the tocotrienol-rich fraction of palm oil, but there is limited evidence that it has antitumor activity. In particular, the effects of gamma-tocotrienol on human colon carcinoma cells have not been reported. To investigate the chemopreventive effects of gamma-tocotrienol on colon cancer, we examined its capacity to inhibit proliferation and induce apoptosis in HT-29 cells and explored the mechanism underlying these effects. METHODS: We cultured HT-29 cells in the presence of gamma-tocotrienol. The effect of gamma-tocotrienol on cell proliferation was investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, mitotic index, and colony formation. The cell-cycle distribution was investigated by flow cytometry. We measured apoptosis by nuclear staining, transmission electron microscopy, and DNA fragmentation. Apoptosis-related proteins and the nuclear factor-kappaB p65 protein were determined by western blotting and immunofluorescence. RESULTS: gamma-Tocotrienol inhibited cell growth and arrested HT-29 cells in G(0)/G(1) phase. The 50% inhibitory concentration was 31.7 micromol/L (48 h). gamma-Tocotrienol-induced apoptosis in HT-29 cells was accompanied by downregulation of Bcl-2, upregulation of Bax, and activation of caspase-3. Furthermore, we found that gamma-tocotrienol reduced the expression level of total nuclear factor-kappaB p65 protein and inhibited its nuclear translocation. CONCLUSION: The results indicated that gamma-tocotrienol inhibits cell proliferation and induces apoptosis in HT-29 cells in a time- and dose-dependent manner, and that this process is accompanied by cell-cycle arrest at G(0)/G(1), an increased Bax/Bcl-2 ratio, and activation of caspase-3. Our data also indicated that nuclear factor-kappaB p65 protein may be involved in these effects.