Unique proteomic signature of JCPyV-infected human astrocytes: from cells to extracellular vesicles

JC polyomavirus (JCPyV) is an opportunistic virus that remains in a latent state in the kidneys of more than half of the human adult population. In rare cases of severe immune suppression, the virus is able to establish a lytic infection of glial cells in the brain, resulting in a debilitating, demyelinating disease known as progressive multifocal leukoencephalopathy (PML). Because of the exceptional species and tissue specificity of the virus, appropriate models of JCPyV infection in the brain are lacking, thus hampering progress towards the development of novel antiviral strategies and biomarkers of disease activity. While PML has traditionally been characterized as a lytic infection of oligodendrocytes, more recent findings suggest an important role for astrocytes during the initial stages of disease. Here, using human induced pluripotent stem cell (hiPSC) derived-astrocytes coupled with a multiparametric approach, we show that 1. JCPyV readily infects and replicates in astrocytes, 2. JCPyV strongly dysregulates the cell biology and 3. these findings adequately reflect ex vivo findings. We perform an in-depth characterization of the effect of JCPyV on the cell proteome over time, demonstrating a strong dysregulation of the cell cycle and activation of the DNA damage response. Furthermore, we show that the proteomic signature observed for infected astrocytes is extended to excreted vesicles, underlining their potential to gain valuable insights into JCPyV propagation in the brain.