Lipid microdomains are important for the entry process of SARS coronavirus to target cells

Glende, Joerg H; Pfefferle, Susanne; Drosten, Christian; Schwegmann‐Weßels, Christel; Herrler, Georg

Cholesterol‐enriched microdomains known as lipid rafts have been shown to be important for the life cycle of several viruses. Here, we investigated whether cholesterol is important during the initial steps of SARS‐CoV spike (S) glycoprotein‐mediated entry. Vero cells were treated with the cholesterol sequestering drug methyl‐β‐cyclodextrin (mβCD) and then exposed to SARS‐CoV and Vesicular stomatitis virus (VSV) pseudotyped with SARS‐CoV spike glycoprotein (VSV‐ΔG‐S). Furthermore, a cell‐based binding assay and a binding assay with soluble S protein demonstrated that the binding of S to its receptor angiotensin‐converting enzyme 2 (ACE2) is affected by cholesterol depletion and that multi‐ligand interactions might be important for the entry process of SARS‐CoV to target cells. Confocal laser microscopy studies and a membrane flotation assay in Vero cells show that the SARS‐CoV receptor is organized within lipid microdomains and cholesterol depletion results in a reduction of ACE2 in the buoyant detergent resistant membrane fraction after Triton‐X 100 solubilization. Further attempts are directed to understand the molecular role of cholesterol during the initial steps of SARS‐CoV life cycle.