Role for tumor necrosis factor-α in JC virus reactivation and progressive multifocal leukoencephalopathy

Area of Science:

• Neurovirology
• Immunology
• Molecular Biology

Background:

• John Cunningham virus (JCV) establishes latent infections and is associated with progressive multifocal leukoencephalopathy (PML), a CNS demyelinating disease.
• Reactivation of latent JCV is linked to conditions like HIV-1/AIDS, where proinflammatory cytokines are elevated in the brain.

Purpose of the Study:

• To investigate the role of tumor necrosis factor-alpha (TNF-α), a key cytokine induced by HIV-1, in regulating JCV transcription and reactivation.
• To explore the potential mechanism of TNF-α-mediated JCV reactivation via the NF-κB pathway.

Main Methods:

• Assessed the effect of TNF-α on JCV early and late transcription in vitro.
• Utilized a heterologous promoter containing the JCV κB element to confirm TNF-α responsiveness.
• Performed immunohistochemistry on brain tissue from HIV-positive PML patients to detect TNF-α and its receptor, TNFR-1.

Main Results:

• TNF-α significantly stimulated both early and late JCV transcription.
• The JCV κB element was identified as conferring TNF-α responsiveness to a heterologous promoter.
• Elevated levels of TNF-α and TNFR-1 were observed in the brain tissue of HIV-positive PML patients.

Conclusions:

• TNF-α plays a role in regulating JCV transcription, suggesting it can promote viral reactivation.
• The κB element is a critical mediator of TNF-α's effect on JCV.
• These findings suggest that TNF-α-induced JCV reactivation via the κB pathway may contribute to the pathogenesis of PML in HIV-1/AIDS patients.