Viral Neurobiology in the Prenatal Brain

ABSTRACT The prenatal brain is uniquely susceptible to viral infections. Such infections threaten 1 in 4 pregnancies and can cause severe neurodevelopmental disorders if not fetal demise. Different viruses lead to strikingly similar clinical outcomes due to overlapping viral neuropathology and the host’s common neuronal response. Such a reality calls for the development of urgently needed prenatal standards of care for prevention or treatment of virally induced brain injury. This need requires a much-deeper understanding of the corresponding neurobiology. A key regulator of the host’s common neuroviral response is the mechanistic target of rapamycin (mTOR) through essential roles in viral autophagy, which affect viral clearance and neuronal survival. There is unsettled controversy, however, about whether mTOR expression and viral autophagy are key defenses against, or requisites to, viral replication and neuronal injury. The PI has new preliminary data connecting mTOR with a novel neuroviral response gene, Hexosaminidase B (HEXB), and suggesting new cellular functions for this genetic complex in activating prenatal viral autophagy to prevent brain injury. Opening new research windows for therapeutic intervention, this sets the context for the proposed K08 study, which rigorously tests the guiding hypothesis that neurodevelopmental gene expression affects prenatal viral susceptibility toward brain injury. Purusing three integrated and synergistic aims in cellular, mouse, and human systems, the PI will investige how gene expression of mTOR and HEXB affects prenatal viral susceptibility and how it might be altered to prevent brain injury. First, human-derived organoids are used to study how expression of mTOR and HEXB affects viral clearance, neuronal survival, and up/downstream pathways (Aim 1). In parallel, this relationship is prenatally evaluated in vivo to determine its impact on postnatal development (Aim 2). Mirrored allelic series of mTOR and HEXB are genetically cross-titrated in these aims, which will shed light on a population genomic analysis to study the extent to which variants in these genes/pathways affect prenatal susceptibility to brain injury (Aim 3). This K08 grant combines research using synergistic/integrated systems with theoretical and technical training by seasoned mentors in neurobiology, neurovirology, and genomics at Children’s National Hospital and NINDS. The individually tailored career development plan uniquely positions the PI, a board-certified prenatal-neonatal critical care neurologist-scientist, to open multiple new research windows into the developing human brain by: (a) deepening our fundamental understanding of prenatal neurovirology and the crticial role of neuro- developmental genes (mTOR & HEXB), regulatory networks, and essential cellular functions; (b) examining genetic regulation of prenatal viral autophagy as a cornerstone for prenatal precision medicine; and (c) tapping into a robust neuroepidemiology research infrastructure (Consortium, CDC, NIH) to identify prenatal susceptibilities. The ultimate goal is to understand the connection between viral neurobiology and neuronal injury in the developing brain to optimize the neuropsychological life experience of future generations of children.