AUTHOR=Govaerts Jonas , Van Breedam Elise , De Beuckeleer Sarah , Goethals Charlotte , D’Incal Claudio Peter , Di Stefano Julia , Van Calster Siebe , Buyle-Huybrecht Tamariche , Boeren Marlies , De Reu Hans , Paludan Søren R. , Thiry Marc , Lebrun Marielle , Sadzot-Delvaux Catherine , Motaln Helena , Rogelj Boris , Van Weyenbergh Johan , De Vos Winnok H. , Vanden Berghe Wim , Ogunjimi Benson , Delputte Peter , Ponsaerts Peter 

TITLE=Varicella-zoster virus recapitulates its immune evasive behaviour in matured hiPSC-derived neurospheroids

JOURNAL=Frontiers in Immunology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1458967

DOI=10.3389/fimmu.2024.1458967

ISSN=1664-3224

ABSTRACT=<p>Varicella-zoster virus (VZV) encephalitis and meningitis are potential central nervous system (CNS) complications following primary VZV infection or reactivation. With Type-I interferon (IFN) signalling being an important first line cellular defence mechanism against VZV infection by the peripheral tissues, we here investigated the triggering of innate immune responses in a human neural-like environment. For this, we established and characterised 5-month matured hiPSC-derived neurospheroids (NSPHs) containing neurons and astrocytes. Subsequently, NSPHs were infected with reporter strains of VZV (VZV<sup>eGFP-ORF23</sup>) or Sendai virus (SeV<sup>eGFP</sup>), with the latter serving as an immune-activating positive control. Live cell and immunocytochemical analyses demonstrated VZV<sup>eGFP-ORF23</sup> infection throughout the NSPHs, while SeV<sup>eGFP</sup> infection was limited to the outer NSPH border. Next, NanoString digital transcriptomics revealed that SeV<sup>eGFP</sup>-infected NSPHs activated a clear Type-I IFN response, while this was not the case in VZV<sup>eGFP-ORF23</sup>-infected NSPHs. Moreover, the latter displayed a strong suppression of genes related to IFN signalling and antigen presentation, as further demonstrated by suppression of IL-6 and CXCL10 production, failure to upregulate Type-I IFN activated anti-viral proteins (Mx1, IFIT2 and ISG15), as well as reduced expression of CD74, a key-protein in the MHC class II antigen presentation pathway. Finally, even though VZV<sup>eGFP-ORF23</sup>-infection seems to be immunologically ignored in NSPHs, its presence does result in the formation of stress granules upon long-term infection, as well as disruption of cellular integrity within the infected NSPHs. Concluding, in this study we demonstrate that 5-month matured hiPSC-derived NSPHs display functional innate immune reactivity towards SeV infection, and have the capacity to recapitulate the strong immune evasive behaviour towards VZV.</p>