Identification of a class of HCV inhibitors directed against the nonstructural protein NS4B.

New classes of drugs are needed to combat hepatitis C virus (HCV), an important worldwide cause of liver disease. We describe an activity of a key domain, an amphipathic helix we termed 4BAH2, within a specific HCV nonstructural protein, NS4B. In addition to its proposed role in viral replication, we validate 4BAH2 as essential for HCV genome replication and identify first-generation small-molecule inhibitors of 4BAH2 that specifically prevent HCV replication within cells. Mechanistic studies reveal that the inhibitors target 4BAH2 function by preventing either 4BAH2 oligomerization or 4BAH2 membrane association. 4BAH2 inhibitors represent an additional class of compounds with potential to effectively treat HCV.

Viral infection of human progenitor and liver-derived cells encapsulated in three-dimensional PEG-based hydrogel.

We have studied the encapsulation of human progenitor cells into 3D PEG hydrogels. Replication-incompetent lentivirus promoter reporter vectors were found to efficiently detect the in vivo expression of human hepatic genes in hydrogel-encapsulated liver progenitor cells. Similarly, hydrogel-encapsulated cells could be efficiently infected with hepatitis C virus, and progeny infectious virus could be recovered from the media supernatants of the hydrogels. Provocatively, the diameters of these virus particles range from approximately 50 to 100 nm, while the calculated mesh size of the 8 k hydrogel is 44.6 +/- 1.7 A. To reconcile how viral particles can penetrate the hydrogels to infect the encapsulated cells, we propose that microfractures/defects of the hydrogel result in a functional pore size of up to 20 fold greater than predicted by theoretical mesh calculations. These results suggest a new model of hydrogel structure, and have exciting implications for tissue engineering and hepatitis virus studies.