Host Cell Genes and West Nile Infection
Search for Potential Targets for Development of Antiviral Agents Among Host Cell Genes Up- and Down-Regulated During West Nile Viral Infection
Tech Area / Field
- MED-DRG/Drug Discovery/Medicine
- BIO-CGM/Cytology, Genetics and Molecular Biology/Biotechnology
3 Approved without Funding
State Research Center of Virology and Biotechnology VECTOR, Russia, Novosibirsk reg., Koltsovo
- Institute of Bioorganic Chemistry, Russia, Moscow
Project summaryA large body of new information on changes of the cellular gene expression patterns during viral infection caused by typical representatives of alpha- and flaviviruses was obtained during ISTC-1177 project implementation. This information demonstrates that the interaction between cell and virus genomes is much more complex than it was believed before. The ability of cellular genes playing to play a new and important roles in the replication of virus in the cell was discovered. Among them are genes of spermidine/spermine N1-acetyltransferase (SSAT), laminin-binding protein (LBP), cytochrome b561, interferon-inducible genes 54K and 56K (IFI-54K, IFI-56K), interferon-inducible gene IFI-10, interferon-inducible gene IFIT4 (RIG-G), RIG-I (RHA helicase), interferon-inducible gene IFP53 (up-regulated), adrenomedullin, adipophilin, cyplasin S (ck 435) genes (down-regulated) and some others, among them many yet unknown genes. The first experiments on blocking LBP on the Vero cell surface using anti-LBP antibodies have demonstrated considerable (over thousand-fold) inhibition of both VEE and TBE viral protein synthesis in these cells. Inhibition of the viral protein synthesis suggests that LBP is a very promising target for antiviral agents. One can suggest that other host genes that were discovered to change their regulation during infection are also prospective targets for developing new antivirals. Similar strategy can be universally applied for determination host gene spectra up- and down-regulated in the course of viral infection thus allowing to identify new candidates for being used in antiviral therapy.
In this proposal we are planning to extend the strategy and results obtained by us earlier for TBEV and VEEV to the West Nile Virus (WNV), which is another representative of flaviviruses commonly found in Africa, Europe, Asia, but now emerging also in the USA and another countries of North America. The virus is remarkable by its very wide host range: it can infect humans, birds, mosquitoes, horses and some other mammals. It causes as mild disease in people such as West Nile fever so more severe diseases such as West Nile encephalitis, West Nile meningitis or West Nile meningoencephalitis. Being a flavivirus, the WNV is expected to touch the same regulatory switches in the host cell as the two other investigated viruses. On the other hand, some peculiarities could also be anticipated. We are going to reveal both common and peculiar features in host-virus interplay for this flaviviruses to create a fundamental basis for development of rational antiviral therapies.
To achieve this goal we are going:
1. To use the information on properties of the genes identified by us previously to find inhibitors for those genes that are up-regulated and either stimulators or gene therapy correctors for down-regulated genes and to test these inhibitors or stimulators/correctors as antiviral agents against West Nile virus in the in vitro tests. As the first candidate target for this part of work we will use RNA-helicase which content is highly increased due to flaviviral infection, and adrenomodullin, which is a down-regulated autocrine growth factor. Other differential genes will also be tested in similar way.
2. To perform a comparative analysis of changes occurring during West Nile infection in mice. The task of this part of the project will be identification of specific genes responding to the in vivo infection with the use of animal model.
3. To prepare microarrays representing the whole sets of genes those changes their expression in various cell types and in different tissues and organs of mice. We will also use it for the statistically significant search of the genetic response in blood leukocytes of patients afflicted with the flaviviral infection (TBE and/or WN infection).
4. To identify the biochemical properties of products of differential genes using bioinformatic tools. On the base of the biochemical properties of the products to continue the search of the antiviral agents as described in #1.
5. To apply a new RNA interference (RNAi) technology as a tool for inhibition of up-regulated genes. For this purpose we will use RNAi to systematically inhibit expression of target genes and correlate the effect of inhibition with the virus replication. The correlation may signify the importance gene for the virus life cycle and put this gene on the list of candidates for antiviral interventions.
As a result, the host genes whose expression varies depending on the virus and those responding similarly to the infection with TBE and WN viruses will be identified. The functional role of the host genes will be studied by comparing their structures with those of the genes and proteins stored in databanks. The expression of host genes connected to WN virus replication will be studied in cells, in animals, and in patients. Data on these genes are essential for the development of specific protection against West Nile and TBE viruses and for development of general means for protection against all flaviviruses. The information is required for better understanding of the mechanisms responsible for cell-viral interaction, which are of importance for eventual development of antiviral medicine, though these applications are beyond the frames of the project.
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