Host lipids in viral assembly and fusion at the nanoscale

• Applicant: Professor Dr. Christian Eggeling
• Subject Area: Virology ; Biophysics ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 545513741

Human pathogens such as enveloped viruses enter and exit host cells by interacting with the cell membrane. In addition, they acquire their lipid envelop from the host cell. Consequently, the characteristics of the viral lipid membrane is of high importance for virus infectivity. There are numerous reported evidences of the manipulation of the host cells’ lipid metabolism and dynamics by viruses during their assembly or cell entry. Using live cell super-resolution dynamic microscopy, we have previously shown how a retrovirus sorts specific lipids during assembly at the plasma membrane of the infected cell to create a favorable environment. However, very little is known about how other viruses, like the recent pandemic SARS-CoV2, assemble at and acquire lipids from the host cells’ and more complex inner membranes, like the endoplasmic reticulum-Golgi Intermediate compartment (ERGIC). There are several key questions pending. Is the lipid composition of viral envelop defined by that of ERGIC and/or by the viral structural proteins? How do these specific lipids control the mobility of viral envelop proteins and thus infectivity? How do these lipids affect viral particle endocytosis or fusion during viral entry? In this project, we will use dynamic super-resolution microscopy in combination with novel functional membrane probes and fluorescent SARS-CoV-2 particles from model systems up to wild-type viruses to decipher the role of lipids in virus assembly and entry. Apart from cholesterol, no other lipid has been identified to play a role in virus-host cell fusion or assembly of SARS-CoV-2. In this project, we will first develop new fluorescent tools for observing host-lipid interactions during virus infection, which includes fluorescent SARS-CoV-2 virus-like particles, fluorescent molecular probes for ER/ERGIC/Golgi and virus assembly and adapted advanced fluorescence microscopy tools. Then, we will (i) identify virus particle lipids using lipidomic, (ii) sense lipid organization and interactions with the viral structural proteins by specially designed fluorescent proteins and environment-sensitive probes that specifically label the inner cell membrane compartments, (iii) monitor changes in lipid dynamics inside living cells while tracking the viral structural proteins, both at few/single molecule level thanks to super-resolution microscopy, and (iv) customize virus-like particles to decipher the interplay with identified lipids and the viral envelope proteins during recognition to the receptor and during entry by fusion or endocytosis. Our project will address these issues thanks to our strong complementary expertise in virology, lipidic membranes, super-resolution dynamic microscopy and innovative fluorescent probes. Expected outcomes will shed the light on molecular manipulation of inner cell lipids by viruses during their assembly and how this facilitates their entry into new host cells.

• DFG Programme: Research Grants
• International Connection: France
• Partner Organisation: Agence Nationale de la Recherche / The French National Research Agency
• Cooperation Partners: Professor Dr. Andrey Klymchenko; Professorin Delphine Muriaux, Ph.D.