A human-derived 3D brain organoid model to study JC virus infection

Area of Science:

• Neuroscience
• Virology
• Stem Cell Biology

Background:

• Progressive Multifocal Leukoencephalopathy (PML) is a severe neurological disease affecting immunosuppressed individuals.
• PML is caused by the JC virus (JCV), which infects human oligodendrocytes and astrocytes, leading to demyelination and neurological deficits.
• Current understanding of PML pathogenesis is limited by the lack of suitable in vitro and animal models due to JCV's specific tropism for human cells.

Purpose of the Study:

• To develop a human-derived brain organotypic system (brain organoid) for modeling JC virus (JCV) infection.
• To investigate the mechanisms of JCV infection and the pathogenesis of Progressive Multifocal Leukoencephalopathy (PML) in a human cellular context.

Main Methods:

• Human-induced pluripotent stem cells (iPSC) were cultured in 3D to generate brain organoids containing neurons, astrocytes, and oligodendrocytes.
• Brain organoids were infected with the JCV MAD4 strain or cerebrospinal fluid from a PML patient.
• Infection was assessed using qPCR, immunofluorescence, and electron microscopy at 1, 2, and 3 weeks post-exposure.

Main Results:

• JC virus (JCV) infection was confirmed in brain organoids exposed to JCV MAD4 or PML patient cerebrospinal fluid.
• Immunocytochemistry and electron microscopy revealed viral antigens and virion particles within oligodendrocytes and astrocytes, but not neurons.
• Quantitative PCR (qPCR) detected JCV in the infected organoids and their surrounding media.

Conclusions:

• The developed brain organoid system serves as a viable human model for studying JCV infection.
• This model facilitates research into the pathogenesis of Progressive Multifocal Leukoencephalopathy (PML).
• The model holds potential for exploring and evaluating therapeutic strategies against PML.