Hippocampal transcriptome profiling in a 22q11.2 deletion syndrome mouse model: comparison with human schizophrenia

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• 22q11.2 deletion syndrome (22q11.2DS) is a major genetic risk factor for schizophrenia.
• The underlying molecular mechanisms connecting 22q11.2DS to schizophrenia remain unclear.

Purpose of the Study:

• To investigate the molecular and behavioral consequences of 22q11.2DS in a mouse model.
• To compare findings with human postmortem brain data from schizophrenia patients.

Main Methods:

• Comprehensive RNA sequencing of the dorsal hippocampus in Df1/+ mice (a 22q11.2DS model).
• Behavioral assessment (contextual fear memory, locomotor activity).
• Integrated pathway analysis and cross-species comparison with human schizophrenia hippocampus transcriptomic data.

Main Results:

• Df1/+ mice displayed impaired contextual fear memory without significant locomotor deficits.
• Transcriptomic analysis revealed upregulated synaptic signaling (glutamatergic, GABAergic) and downregulated translational machinery.
• Cross-species analysis showed concordant differential expression in key pathways, notably "regulation of postsynaptic membrane potential," and downregulated glial/extracellular matrix genes.

Conclusions:

• 22q11.2DS is associated with enhanced synaptic gene expression and reduced protein synthesis capacity in the hippocampus.
• Excitatory-inhibitory imbalance and altered synaptic function are shared hippocampal mechanisms in 22q11.2DS and schizophrenia.
• The Df1/+ mouse model demonstrates translational relevance for studying schizophrenia pathogenesis.