Hepatocyte NAD(P)H Oxidases Contribute to Reactive Oxygen Species Generation in Hepatitis C Virus Infection

Reactive oxygen species (ROS) production has been identified as a critical mechanism in the pathogenesis of hepatitis C virus (HCV) infection. Researchers from the University States have discovered that hepatocyte NAD(P)H oxidases are a significant source of ROS during HCV infection. The study found that HCV increases the generation of superoxide and hydrogen peroxide close to the hepatocyte nucleus, with the Nox4 enzyme playing a key role in this process. The researchers also demonstrated that HCV-induced ROS production can be reduced by targeting Nox1 and Nox4 with small interfering RNAs.

Key Takeaways:

• HCV infection leads to increased expression of Nox1 and Nox4 in hepatocytes, contributing to ROS production.
• Nox4 is primarily localized in the nuclear compartment of hepatocytes, especially in the presence of HCV.
• Targeting Nox1 and Nox4 with small interfering RNAs can decrease HCV-induced ROS production.
• HCV infection increases the level of transforming growth factor beta 1 (TGFbeta1), which in turn elevates Nox4 expression.
• TGFbeta1 and Nox4 contribute to HCV-induced pathogenesis by increasing ROS production.

Statistics:

• 52% increase in Nox1 mRNA levels in Huh7 cells infected with genotype 2a HCV (de Mochel et al., 2010).
• 3.5-fold increase in Nox4 mRNA levels in telomerase-reconstituted primary human hepatocytes infected with genotype 1b HCV (de Mochel et al., 2010).
• 2.5-fold increase in Nox1 protein levels in HCV-infected human liver compared to uninfected liver (de Mochel et al., 2010).
• 4.1-fold increase in Nox4 protein levels in HCV-infected human liver compared to uninfected liver (de Mochel et al., 2010).

Sources:

• de Mochel N.S., et al. (2010). Hepatocyte NAD(P)H oxidases as an endogenous source of reactive oxygen species during hepatitis C virus infection. Hepatology, 52(1), 47-59.