Cytomegalovirus manipulation of functional cortical tissue development

PROJECT SUMMARY Human cytomegalovirus (HCMV) infects much of the world’s population and establishes a life-long persistent infection defined by both lytic and latent states, and HCMV continues to be a significant issue in human health. HCMV is the leading cause of non-heritable birth defects in the United States and likely around the world. If the virus crosses the placental barrier, HCMV replicates in developing neural tissues resulting in significant neurodevelopmental consequences and central nervous system damage. Several antiviral treatments exist but are not approved for use during pregnancy due to toxicity and potential teratogenic effects. Our collaborative project aims to address the significant deficiencies in understanding the underlying neural pathogenesis of congenital HCMV infection in human neural tissues and the lack of antiviral approaches. In this regard, we have found that HCMV infection induces significant downregulation of key neurodevelopmental transcripts and pathways and leads to substantial disruption of structural organization, differentiation potential, and calcium and electrophysiological function in human induced pluripotent stem cell (iPSC)-derived neural progenitor cells (NPCs) and 3-dimentional cortical organoids. Interestingly, we further discovered that these pathologies were not dependent on full viral replication and that standard antiviral approaches were insufficient to restore normal human brain cell development and function. Moreover, the production of nitric oxide as an innate immune response to limit viral replication was overtly detrimental to cortical organoid tissue structure and NPC differentiation potential. Therefore, we will expand on these data to (1) define the transcriptional and cellular disruptions to developing human neural cells by HCMV infection, (2) determine the impact of specific viral proteins in disrupting human brain development, and (3) elucidate the non-cell autonomous influence of HCMV infected microglia on human brain development. These aims are based on our significant amount of published and preliminary data that sets the foundation for the proposed experiments. We will use bulk, single cell, and spatial transcriptomic technologies, calcium imaging, microelectrode array, and sophisticated microglia-cortical organoid iPSC culturing and analysis approaches to better elucidate the viral and cellular mechanisms contributing to the neurodevelopmental impact of HCMV infection. Congenital HCMV infection can have devastating effects on children, pose significant challenges for parents and caregivers, and continues to be a significant world health problem. The collaborative team is uniquely qualified to carry out these highly novel and impactful studies that will uncover fundamental aspects of HCMV infection in human brain tissues with the ultimate goal of aiding the development of appropriate, targeted, and effective therapeutic interventions.