CNSC-67. ANATOMICAL ORGANIZATION AND ELECTRICAL PROPERTIES OF GLIOMA-INNERVATING NEURONS

Abstract Gliomas are the most common malignant primary brain tumors and are often associated with severe neurological deficits and mortality. Unlike many cancers, gliomas rarely metastasize outside the brain, indicating a possible dependency on the brain’s unique microenvironment. Recent discoveries have highlighted the existence of neuron-glioma synapses, suggesting that glioma cells depend on neuronal inputs and AMPA-receptor-mediated glutamate signaling for their proliferation. Yet, the specific locations and properties of the neurons that innervate gliomas remain elusive. In this study, we utilized transsynaptic tracing with a pseudotyped, glycoprotein-deleted rabies virus to specifically infect TVA and glycoprotein-expressing human glioblastoma cells in an orthotopic xenograft model. This approach allowed us to identify the presynaptic neuronal inputs to the glioma. Comprehensive whole-brain mapping and quantification revealed that these glioma-innervating neurons, predominantly glutamatergic, exhibit a consistent input pattern influenced by the tumor’s locations and engage selective neuromodulatory pathways. Notably, the electrophysiological properties of these neurons mirror those innervating the cortex in vivo. Our study introduces a novel method for investigating glioma-innervating neurons and reveals that these neurons are consistently integrated into the glioma network, displaying distinctive location-dependent neuromodulatory patterns. Our findings offer a promising scaffold for future interventions aimed at disrupting these critical neuronal inputs, potentially redefining therapeutic strategies against brain tumors.