Project Details
Projekt
Characterizing the role of selected host factors in replication and pathogenicity of clinically-relevant influenza A viruses in the human lung
Applicant
Dr. Jessica Freifrau von Recum
Subject Area
Virology
Term
from 2015 to 2017
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 275015707
Influenza A virus (IAV) is an RNA virus encoding up to 13 viral proteins. Due to this limited coding capacity IAV needs to use the host cellular machinery for completing its infection cycle. High-throughput screens have identified hundreds of human proteins indispensable for IAV replication. Our research group performed a genome-wide RNAi screen that identified 295 cellular cofactors required for early-stage IAV replication. In a subsequent affinity-purification mass spectrometry analysis of all IAV proteins about 60 host factors were detected that directly overlap with data from published siRNA screens. These host factors that not only play a role in IAV replication but also directly interact with IAV proteins will be subject of our investigation. We aim to further characterize a selection of orthogonally validated candidates from the list of host factors regarding their roles in replication and pathogenicity of three clinically relevant IAV strains - seasonal H3N2, pandemic H1N1 and highly-pathogenic H5N1. These viruses differ in their degrees of virulence, which enables us to further examine host factors affecting viral pathogenesis. However, immortalized human epithelial cells like A549, which are widely used for IAV research, can have potential drawbacks such as differences in host regulatory networks compared to non-tumorigenic cells. Therefore, additional models are needed to perform comprehensive studies on human host factors that influence the outcome of an IAV infection. Human ex vivo lung tissue can be infected with IAVs to analyze e.g. virus replication, cell tropism and cytokine induction making it a particularly useful model system. Its advantage compared to cell culture systems is that this model applies authentic human tissue in which different cell types are still connected in the 3D structure and able to interact and communicate with each other. Replication of IAVs in the lung tissue correlates with their pathogenicity in humans, which makes this model ideal to also investigate host factors involved in IAV virulence. We plan to silence selected candidate genes in lung tissue by making use of specialized molecules designed to work in complex tissues named Vivo-Morpholinos (VMs). VMs have been successfully used to silence genes in different tissues as well as in living animals like mice. The lung tissue that no longer expresses the selected gene will then be analyzed for virus replication, cellular immune responses and other endpoints compared to lung tissue treated with non-target control VMs. In summary, our project concentrates on the characterization of host factors involved in replication and pathogenicity of clinically relevant IAVs in a physiologically-relevant human lung tissue model. These studies will not only improve our understanding of the roles of these host factors in the IAV infection cycle but also provide critical insight into the future development of novel antiviral drugs against IAV.
DFG Programme
Research Fellowships
International Connection
USA
