Enveloped viruses fusion inhibitor LJ001: Synergism between lipid order, surface pressure and location.

HOLLMANN A; CASTANHO MA; SANTOS NC

Whistler

Simposio; Keystone Symposia meeting on Cell Biology of Virus Entry, Replication and Pathogenesis; 2012

Keystone Symposia

Wolf et al. [PNAS 2010, 107: 3157] described LJ001, a broad-spectrum small-molecule inhibitor that prevents enveloped viruses entry at a step after virus binding but before virus-cell fusion. In the present work, we studied the interactions of LJ001 and LJ025 (an inactive analog, used as control) with biomembrane models and blood cells, in order to clarify the mechanism of action at the molecular level of this inhibitor. By fluorescence spectroscopy measurements, we quantified the partition and determined the location of these two molecules on lipid membranes, concluding that both are inserted in the membrane. However, LJ001 locates closer to the lipid-water interface than LJ025, which stays deeper in the acyl chain region. We also investigated the changes that these molecules are able to promote on the packing of membrane components, based on surface pressure measures using lipid monolayers, which showed that LJ001 induces a much larger increase in lateral pressure. Finally, by fluorescence anisotropy measurements of DPH or TMA-DPH, we observed that LJ001 was able to rigidify model membranes mimicking cell or HIV membranes, but not live blood cells. The obtained information allowed us to conclude that the specific location of LJ001 in the bilayer, plus its ability to increase the packing and ordering of lipids, promote a synergistic effect between membrane curvature and fluidity, resulting in an inhibition of the fusion between viral and cellular membranes.