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Gene Replicates HCV in Human Cells

Researchers from The Rockefeller University in New York found that the overexpression of the SEC14L2 gene led to hepatitis C virus infection replication in human liver cell cultures, according to new data published in Nature.

“Being able to easily culture HCV in the lab has many important implications for basic science research,” Charles Rice, of The Rockefeller University, said in a press release. “There is still much we don’t understand about how the virus operates, and how it interacts with liver cells and the immune system.”

Charles Rice

Rice and colleagues hypothesized that there were missing factors in cultured cells that were required for replicating clinical isolates. To determine any missing factors, they analyzed and transduced 7,000 Huh-7.5 human hepatoma cells with a pooled lentivirus-based human complementary DNA (cDNA) library, “transfected the cells with HCV subgenomic replicons lacking adaptive mutations and selected for stable replicon colonies,” according to the research.

The researchers were able to identify a single cDNA, SEC14L2, which enabled RNA replication of diverse HCV genotypes in several hepatoma cell lines.

“This effect was dose-dependent and required the continuous presence of SEC14L2,” the researchers wrote.

Analyses also showed that full-length HCV genomes also replicated and produced low levels of infectious virus.

“Practically speaking, this means that if scientists want to study HCV from an infected patient, it’s now possible to take a blood sample, inoculate the engineered cells, and grow that patient’s form of the virus in the lab,” Mohsan Saeed, also from The Rockefeller University, said in the release.

Additionally, SEC14L2-expressing Huh-7.5 cells also “supported HCV replication following inoculation with patient sera,” the researchers wrote.

SEC14L2 was found to be “highly permissive” with the wild-type HCV. Splice isoforms of SEC14L2 encoded shorter proteins, which did not facilitate HCV replication. Two other SEC14L2-related proteins, SEC14L3 and SEC14L4, which have been previously found in human cells, were not found in these Huh-7.5 cells. The SEC14L3 allowed low level HCV replication, whereas SEC14L4 had no effect at all.

In an era where HCV is being treated and cured, this cell culture process may be useful when determining treatment for a patient, according to Saeed.

“As more patients are treated, drug resistant forms of HCV are emerging,” Saeed said. “Having a cell culture system where patient isolates can be grown and tested for resistance or susceptibility to alternative antiviral drug combinations should be useful for optimizing re-treatment strategies for those that fail treatment.”

The researchers concluded: “This provides a foundation for development of in vitro replication systems for all HCV isolates, creating a useful platform to dissect the mechanisms by which cell culture-adaptive mutations act.” – by Melinda Stevens

Disclosures: Healio.com/Hepatology was unable to confirm relevant financial disclosures at the time of publication.