Pan-Genotype Hepatitis E Virus Replication in Stem Cell-Derived Hepatocellular Systems.

Area of Science:

• Hepatology
• Virology
• Stem Cell Biology

Background:

• Hepatitis E virus (HEV) genotypes 1-4 exhibit diverse geographical distributions, transmission routes, and pathogenesis.
• Primary HEV isolates poorly infect cell cultures, limiting research to adapted strains that may alter virus biology.
• Understanding HEV host interactions is crucial for explaining variations in disease presentation.

Purpose of the Study:

• To investigate the infection and replication of primary HEV isolates in hepatocyte-like cells (HLCs).
• To compare the replication kinetics, drug sensitivity, and innate immune response activation of primary HEV isolates versus cell culture-adapted strains.
• To utilize a genetically tractable HLC system for studying HEV biology and potential therapeutic targets.

Main Methods:

• HLCs derived from human embryonic and induced pluripotent stem cells were used to study HEV infection.
• Quantitative reverse-transcriptase polymerase chain reaction, immunofluorescence assays, and enzyme-linked immunosorbent assays were employed.
• CRISPR-Cas9 was used to disrupt and rescue cyclophilin A (CYPA) expression in HLCs to assess its role in HEV replication.

Main Results:

• HLCs supported infection by nonadapted primary isolates of HEV genotypes 1-4.
• HEV infection in HLCs triggered a replication-dependent type III interferon response.
• Primary HEV isolate replication was not impacted by CYPA gene disruption or cyclosporine A treatment, unlike cell culture-adapted strains.

Conclusions:

• Cell culture adaptation significantly alters HEV replicative capabilities.
• HLCs provide a physiologically relevant and genetically tractable model for studying primary HEV isolates.
• This HLC model can facilitate the development of novel HEV drugs and personalized treatment strategies, particularly for ribavirin-resistant cases.