Differential gene expression and immune cell infiltration in maedi-visna virus-infected lung tissues.

BACKGROUND: Maedi-visna virus (MVV) is a lentivirus that infects monocyte/macrophage lineage cells in sheep, goats, and wild ruminants and causes pneumonia, mastitis, arthritis, and encephalitis. The immune response to MVV infection is complex, and a complete understanding of its infection and pathogenesis is lacking. This study investigated the in vivo transcriptomic patterns of lung tissues in sheep exposed to MVV using the RNA sequencing technology. RESULT: The results indicated that 2,739 genes were significantly differentially expressed, with 1,643 downregulated genes and 1,096 upregulated genes. Many variables that could be unique to MVV infections were discovered. Gene Ontology analysis revealed that a significant proportion of genes was enriched in terms directly related to the immune system and biological responses to viral infections. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the most enriched pathways were related to virus-host cell interactions and inflammatory responses. Numerous immune-related genes, including those encoding several cytokines and interferon regulatory factors, were identified in the protein-protein interaction network of differentially expressed genes (DEGs). The expression of DEGs was evaluated using real-time polymerase chain reaction and western blot analysis. CXCL13, CXCL6, CXCL11, CCR1, CXCL8, CXCL9, CXCL10, TNFSF8, TNFRSF8, IL7R, IFN-γ, CCL2, and MMP9 were upregulated. Immunohistochemical analysis was performed to identify the types of immune cells that infiltrated MVV-infected tissues. B cells, CD4+ and CD8+ T cells, and macrophages were the most prevalent immune cells correlated with MVV infection in the lungs. CONCLUSION: Overall, the findings of this study provide a comprehensive understanding of the in vivo host response to MVV infection and offer new perspectives on the gene regulatory networks that underlie pathogenesis in natural hosts.

Modulation of autophagy affected tumorigenesis induced by the envelope glycoprotein of JSRV.

Ovine pulmonary adenocarcinoma (OPA), caused by the jaagsiekte sheep retrovirus (JSRV), is a chronic, progressive, and contagious lung tumor that seriously affects sheep production. It also represents a valuable animal model for several human lung adenocarcinomas. However, little is known about the role of autophagy in OPA tumorigenesis. Here, Western blotting combined with transmission electron microscopy examination and Cyto-ID dye staining was employed for evaluation of changes of autophagic levels. The results of the present study showed that expression of the autophagy marker proteins Beclin-1 and LC3 was decreased in OPA lung tissues, as well as in cells overexpressing the envelope glycoprotein of JSRV (JSRV Env). Reduced numbers of autophagosomes were also observed in cells overexpressing JSRV Env, although assessment of autophagic flux showed that JSRV Env overexpression did not block the formation of autophagosomes, suggesting increased degradation of autolysosomes. Last, mouse xenograft experiments indicated that inhibition of autophagy by 3-methyladenine suppressed both tumor growth and the epithelial-to-mesenchymal transition. In conclusion, JSRV, through JSRV Env, takes advantage of the autophagy process, leading to the development of OPA.

Next-generation sequencing for the genetic characterization of Maedi/Visna virus isolated from the northwest of China.

BACKGROUND: Maedi/Visna virus (MVV) is a contagious viral pathogen that causes considerable economic losses to the sheep industry worldwide. OBJECTIVES: In China, MVV has been detected in several regions, but its molecular characteristics and genetic variations were not thoroughly investigated. METHODS: Therefore, in this study, we conducted next-generation sequencing on an MVV strain obtained from northwest China to reveal its genetic evolution via phylogenetic analysis. RESULTS: A MVV strain obtained from Inner Mongolia (NM) of China was identified. Sequence analysis indicated that its whole-genome length is 9193 bp. Homology comparison of nucleotides between the NM strain and reference strains showed that the sequence homology of gag and env were 77.1%-86.8% and 67.7%-75.5%, respectively. Phylogenetic analysis revealed that the NM strain was closely related to the reference strains isolated from America, which belong to the A2 type. Notably, there were 5 amino acid insertions in variable region 4 and a highly variable motif at the C-terminal of the surface glycoprotein (SU5). CONCLUSIONS: The present study is the first to show the whole-genome sequence of an MVV obtained from China. The detailed analyses provide essential information for understanding the genetic characteristics of MVV, and the results enrich the MVV library.

[Effect of cell culture conditions on antibody heterogeneity].

With the advantage of clear target and little side effect, antibody drug has attracted widely attention of worldwide pharmaceutical companies. However, large scale mammalian cell culture and antibody quality analysis are the bottlenecks of antibody drug industrialization in China. Especially due to the significant effect of cell culture conditions on antibody heterogeneity. Therefore, it is extremely urgent to optimize cell culture conditions to favor the demands of antibody drug development. This review summarized the most recent advances in the effect of cell culture conditions on antibody quality, followed by addressing the key issues that might be strategically important for domestic antibody drug development.

Mechanism analysis of effect of oxygen on molecular weight of hyaluronic acid produced by Streptococcus zooepidemicus.

Dissolved oxygen (DO) has a significant effect on the molecular weight of hyaluronic acid (HA) during the fermentation of Streptococcus zooepidemicus. Therefore, to further investigate the effect of DO on the yield and molecular weight of HA, this study compared the metabolic flux distribution of S. zooepidemicus under aerobic conditions at various DO levels. The metabolic flux analysis demonstrated that the HA synthesis pathway, considered a dependent network, was little affected by the DO level. In contrast, the fluxes of lactate and acetate were greatly influenced, and more ATP was generated concomitant with acetate at a high DO level. Furthermore, the has gene expression and HA synthase activity were both repressed under anaerobic conditions, yet not obviously affected under aerobic conditions at various DO levels. Therefore, it was concluded that the HA molecular weight would seem to depend on the concomitant effect of the generation of ATP and reactive oxygen species. It is expected that this work will contribute to a better understanding of the effect of the DO level on the mechanism of the elongation of HA chains.

[Effect of agitation on hyaluronic acid produced by Streptococcus zooepidemicus by using computational fluid dynamics].

Agitation plays an important role in the hyaluronic acid (HA) fermentation process. However, views about the effect of agitation on HA production remain controversial. We investigated the effect of agitation on cell growth and HA synthesis during HA fermentation process by using Computational Fluid Dynamics (CFD) technology. The results showed that the biomass and HA yield changed a little with the increase of impeller speed, but the HA molecular weight firstly increased and then decreased. The results of phase agitation control strategy demonstrated that the influence of agitation on the HA molecular weight mainly exhibited at the stage of HA synthesis. Moreover, the CFD simulation results indicated that when impeller speed increased, the mixing time reduced while the shear rate increased significantly. The removal of anchor could moderate the contradiction between the mixing time and shear rate, and finally the HA molecular weight increased by 23.9%. The results of this work could provide guidelines for optimizing the HA fermentation, as well as the bioreactor design and scaling up.

Effect of oxygen and shear stress on molecular weight of hyaluronic acid.

Dissolved oxygen (DO) and shear stress have pronounced effects on hyaluronic acid (HA) production, yet various views persist about their effect on the molecular weight of HA. Accordingly, this study investigated the effects of DO and shear stress during HA fermentation. The results showed that both cell growth and HA synthesis were suppressed under anaerobic conditions, and the HA molecular mass was only (1.22+/-0.02) x 106 Da. Under aerobic conditions, although the DO level produced no change in the biomass or HA yield, a high DO level favored the HA molecular mass, which reached a maximum value of (2.19+/- 0.05) x 106 Da at 50% DO. Furthermore, a high shear stress delayed the rate of HA synthesis and decreased the HA molecular weight, yet had no clear effect on the HA yield. Therefore, a high DO concentration and mild shear environment would appear to be essential to enhance the HA molecular weight.