Functional Neuroligin-2-MDGA1 interactions differentially regulate synaptic GABAARs and cytosolic gephyrin
Tommaso Zeppillo1,2, Heba Ali1,3, Sowbarnika Ravichandran2,4
1Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, 37075, Göttingen, Germany.
Communications Biology
|September 16, 2024
Summary
Loss of Neuroligin-2 (Nlgn2) causes synaptic deficits and anxiety. However, removing MDGA1, a binding partner, rescues these effects, suggesting MDGA1 as a therapeutic target for Nlgn2-related neurological disorders.
Area of Science:
- Neuroscience
- Synaptic Plasticity
- Molecular Psychiatry
Background:
- Neuroligin-2 (Nlgn2) is crucial for GABAergic synapses, mediating inhibitory neurotransmission by scaffolding GABAA receptors via gephyrin.
- Nlgn2 function is complex, with synapse-specific variations suggesting the involvement of interacting proteins and redundancies.
- The precise mechanisms by which Nlgn2 function is modulated remain poorly understood, particularly concerning its interaction partners.
Purpose of the Study:
- To investigate the modulatory roles of MDGA1 and MDGA2 on Neuroligin-2 (Nlgn2) function in the hippocampal CA1 region.
- To elucidate the impact of Nlgn2-MDGA1 interactions on synaptic structure, function, and behavior in vivo.
- To explore the therapeutic potential of targeting Nlgn2-MDGA1 interactions for psychiatric disorders.
Main Methods:
- Utilized knockout mouse models for Nlgn2, MDGA1, and MDGA2.
- Assessed synaptic function through electrophysiological recordings of inhibitory synaptic transmission.
- Quantified gephyrin scaffold assembly and localization using immunohistochemistry and microscopy.
- Evaluated anxiety-related behaviors using established behavioral assays.
Main Results:
- Loss of MDGA1, but not heterozygous MDGA2 deletion, ameliorated cytosolic gephyrin aggregation and restored inhibitory synaptic transmission in Nlgn2 knockout mice.
- MDGA1 deletion alleviated exacerbated anxiety-related behaviors observed in Nlgn2 knockout mice.
- Combined Nlgn2 and MDGA1 deletion led to an exacerbated layer-specific loss of gephyrin puncta, indicating a critical role in synaptic organization.
Conclusions:
- MDGA1 significantly modulates Nlgn2 function at GABAergic synapses, influencing gephyrin scaffold assembly and synaptic transmission.
- Targeting the interaction between Nlgn2 and MDGA1 may offer a novel therapeutic strategy for psychiatric disorders associated with synaptic dysfunction.
- Cytosolic gephyrin aggregation, influenced by Nlgn2 and MDGA1, represents a promising target for future therapeutic interventions.
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