# Monosynaptic tracing defines circuit connectivity of human high-grade glioma in the adult mouse brain

> **NIH NIH F31** · UNIVERSITY OF PENNSYLVANIA · 2024 · $48,974

## Abstract

Project Summary
My long-term career aspiration is to become a physician-scientist committed to bringing novel brain tumor
therapies from bench to bedside by leading an independent basic science research group. This proposal is a
first step in achieving this goal by providing crucial support for an integrated neuroscience/cancer biology-based
training plan in the context of brain tumor research at the Perelman School of Medicine, University of
Pennsylvania. Glioblastoma is a universally fatal brain cancer that functionally integrates into the normal neural
circuitry. It has been reported that neuronal activity drives tumor progression via glutamatergic synapses onto
tumor cells and, in parallel, glioblastoma cells alter neuronal excitability, remodel neural circuits, and impair
cognitive function. However, little is known regarding the cellular diversity and circuit architecture of neurons that
are connected with tumor cells. Understanding the anatomic and cell type distribution of these connected
neurons may reveal unique functional roles of select neuronal subsets in glioma pathogenesis. We hypothesize
that glioblastoma receives functional synapses from both local and long-range neuronal projections, consisting
of not only glutamatergic but also neuromodulatory inputs. In the normal brain, neuromodulatory inputs project
diffusely throughout the brain and play an important role in modulating neuronal excitability, and thus may also
function in regulating glioma. In this proposal, we seek to define the glioblastoma connectome using
monosynaptic rabies virus (RBV) for retrograde trans-synaptic tracing and monosynaptic herpes simplex virus
(HSV) for anterograde trans-synaptic tracing in a xenograft mouse model. In Aim 1, we will utilize an in vivo
model to map the whole-brain inputs onto glioblastoma by transplanting patient-derived glioblastoma organoids
(GBOs) to various clinically relevant brain regions in immunodeficient mice. Preliminary studies revealed labeling
of diverse neuronal subtypes in various brain regions, and, in particular, basal forebrain cholinergic neurons
projecting to transplanted glioblastoma cells in both cortical and subcortical regions. We will confirm cholinergic
inputs with HSV-based anterograde trans-synaptic tracing as well as electrophysiological recordings. In Aim 2,
we will study the functional significance of these cholinergic neuromodulatory inputs onto glioblastoma by
performing calcium imaging and single-cell RNA sequencing of glioblastoma organoids treated with acetylcholine
as well as assess the impact of acetylcholine on tumor cell invasion in vitro and in vivo. We believe that project
outcomes will elucidate the complex brain-wide interactions between tumor cells and diverse neuronal
populations and investigate the significance of cholinergic inputs in glioma disease progression, thereby
providing novel therapeutic avenues for glioblastoma.

## Key facts

- **NIH application ID:** 10901220
- **Project number:** 1F31NS137664-01
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** Yusha Sun
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $48,974
- **Award type:** 1
- **Project period:** 2024-06-01 → 2027-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10901220

## Citation

> US National Institutes of Health, RePORTER application 10901220, Monosynaptic tracing defines circuit connectivity of human high-grade glioma in the adult mouse brain (1F31NS137664-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10901220. Licensed CC0.

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