Influenza Virus Hijacks Human Cell Machinery for Replication, Study Reveals

An international research effort, spearheaded by scientists at the European Molecular Biology Laboratory (EMBL) in Germany, has detailed for the first time how Influenza A virus commandeers human cells to replicate. The study, published in Nature Microbiology, uncovers the virus's sophisticated manipulation of cellular processes, which are normally dedicated to protein production and transport. By exploiting these internal cellular mechanisms, the virus effectively forces the cell to produce more viral copies instead of performing its own functions. This breakthrough is considered a crucial step towards developing more targeted treatments and vaccines against influenza, a disease that continues to cause hundreds of deaths annually.

The research identified two primary strategies employed by the virus. Firstly, the virus utilizes its surface protein, hemagglutinin, as a key to enter cells. Within the cell, this viral protein requires processing, similar to how the cell prepares its own proteins. The study found that the virus leverages the cell's own production lines and human proteins, some of which were previously of unknown function, to correctly modify hemagglutinin and evade the immune system. Secondly, the virus disrupts internal cellular structures known as paraspeckles, which are located in the cell nucleus and sequester specific proteins. Upon infection, the virus causes these structures to disassemble, releasing their stored proteins. The virus then repurposes these released proteins as raw material for its own replication. Researchers were particularly surprised by the paraspeckle disruption, suggesting it is a deliberate viral strategy rather than an incidental effect, potentially weakening the cell's defense mechanisms while simultaneously providing resources for viral multiplication.

This detailed understanding was made possible by an adapted cross-linking mass spectrometry (XL-MS) technique, developed by researchers at the Leibniz Institute for Molecular Pharmacology (FMP) in Berlin. Unlike previous methods that required cell lysis, this technique captures protein interactions within living, infected cells in real-time. The data gathered was then combined with a modified version of the AI program AlphaFold. This integration allowed scientists to not only identify specific viral and cellular protein connections but also to simulate their physical interactions, providing an unprecedented view of the infection process.