Human Cytomegalovirus Disruption of Calcium Signaling in Neural Progenitor Cells and Organoids.

The herpesvirus human cytomegalovirus (HCMV) is a leading cause of congenital birth defects. Infection can result in infants born with a variety of symptoms, including hepatosplenomegaly, microcephaly, and developmental disabilities. Microcephaly is associated with disruptions in the neural progenitor cell (NPC) population. Here, we defined the impact of HCMV infection on neural tissue development and calcium regulation, a critical activity in neural development. Regulation of intracellular calcium involves purinergic receptors and voltage-gated calcium channels (VGCC). HCMV infection compromised the ability of both pathways in NPCs as well as fibroblasts to respond to stimulation. We observed significant drops in basal calcium levels in infected NPCs which were accompanied by loss in VGCC activity and purinergic receptor responses. However, uninfected cells in the population retained responsiveness. Addition of the HCMV inhibitor maribavir reduced viral spread but failed to restore activity in infected cells. To study neural development, we infected three-dimensional cortical organoids with HCMV. Infection spread to a subset of cells over time and disrupted organoid structure, with alterations in developmental and neural layering markers. Organoid-derived infected neurons and astrocytes were unable to respond to stimulation whereas uninfected cells retained nearly normal responses. Maribavir partially restored structural features, including neural rosette formation, and dampened the impact of infection on neural cellular function. Using a tissue model system, we have demonstrated that HCMV alters cortical neural layering and disrupts calcium regulation in infected cells.IMPORTANCE Human cytomegalovirus (HCMV) replicates in several cell types throughout the body, causing disease in the absence of an effective immune response. Studies on HCMV require cultured human cells and tissues due to species specificity. In these studies, we investigated the impact of infection on developing three-dimensional cortical organoid tissues, with specific emphasis on cell-type-dependent calcium signaling. Calcium signaling is an essential function during neural differentiation and cortical development. We observed that HCMV infects and spreads within these tissues, ultimately disrupting cortical structure. Infected cells exhibited depleted calcium stores and loss of ATP- and KCl-stimulated calcium signaling while uninfected cells in the population maintained nearly normal responses. Some protection was provided by the viral inhibitor maribavir. Overall, our studies provide new insights into the impact of HCMV on cortical tissue development and function.