Cholinergic Neuronal Activity Promotes Diffuse Midline Glioma Growth through Muscarinic Signaling

Area of Science:

• Neuroscience
• Oncology
• Cell Biology

Background:

• Neuronal activity influences oligodendrocyte precursor cell (OPC) and glioma proliferation.
• Diffuse midline glioma (DMG) arises in midline structures and is promoted by glutamatergic and GABAergic signaling.
• The role of neuromodulatory neurons, particularly midbrain cholinergic neurons, in DMG progression is largely unknown.

Purpose of the Study:

• To investigate the circuit-specific effects of midbrain cholinergic neuron activity on healthy OPC and DMG proliferation.
• To elucidate the molecular mechanisms underlying cholinergic modulation of DMG growth.

Main Methods:

• Optogenetic stimulation of specific midbrain cholinergic nuclei (PPN, LDT) in vivo.
• Co-culture systems with human induced pluripotent stem cell (hiPSC)-derived cholinergic neurons and DMG cells.
• Single-cell RNA sequencing of patient-derived DMG samples.
• Pharmacological blockade of muscarinic acetylcholine receptors (M1, M3).

Main Results:

• Optogenetic stimulation of PPN and LDT promoted DMG growth in specific midline locations (pons, thalamus).
• Cholinergic neurons formed direct networks with DMG cells, enhancing proliferation and invasion.
• DMG cells expressed CHRM1 and CHRM3 receptors, mediating acetylcholine's proliferative effects.
• Pharmacological blockade of M1/M3 receptors abolished activity-dependent DMG proliferation.

Conclusions:

• Midbrain cholinergic neurons modulate DMG growth through long-range projections to midline structures.
• Activity-dependent DMG proliferation is mediated by M1 and M3 muscarinic acetylcholine receptors.
• These findings reveal a novel pathway for DMG progression and suggest potential therapeutic targets.