Modeling GABAergic hyperexcitability in sleep bruxism patient-derived brainstem neurons using a multielectrode array...

Area of Science:

• Neuroscience
• Stem Cell Biology
• Electrophysiology

Background:

• Sleep bruxism (SB) is linked to impaired brainstem inhibitory regulation, particularly involving GABAergic neurons.
• Previous studies show intrinsic neuronal hyperexcitability in SB patients using low-throughput methods.
• A high-throughput platform is needed for large-scale phenotypic screening of SB-related neuronal dysfunction.

Purpose of the Study:

• To establish a robust, high-throughput multielectrode array (MEA) platform for assessing electrophysiological phenotypes of SB-derived neurons.
• To quantitatively analyze neuronal activity and GABAergic function in SB patient-derived cells.
• To identify underlying mechanisms of hyperexcitability in sleep bruxism.

Main Methods:

• Human induced pluripotent stem cells (hiPSCs) from SB patients and controls were differentiated into ventral brainstem-like neurons.
• Neuronal composition was confirmed via immunocytochemistry (TUBB3+, GAD1/2+).
• Spontaneous neuronal firing was measured using MEA, and extracellular GABA levels were quantified via ELISA.

Main Results:

• Neuronal differentiation efficiency was comparable between SB and control groups.
• While steady-state firing rates were similar, SB neurons showed increased firing after GABA removal (medium change).
• Elevated extracellular GABA concentrations were observed in SB-derived neurons, suggesting hypersecretion that masked intrinsic hyperexcitability.

Conclusions:

• A high-throughput MEA platform was successfully developed for quantifying SB-related electrophysiological phenotypes.
• SB-derived GABAergic neurons exhibit constitutive hyperexcitability and excessive GABA release.
• These findings provide mechanistic insights into SB and a scalable framework for developing new therapies.