Pten regulates neuronal arborization and social interaction in mice

Area of Science:

• Neuroscience
• Genetics
• Developmental Biology

Background:

• The phosphatase and tensin homolog (Pten) gene is crucial for regulating cell size and number.
• Pten mutations are linked to macrocephaly and Lhermitte-Duclos disease in mice.
• PTEN mutations have been observed in individuals with autism spectrum disorders (ASD), but a direct link is not established.

Purpose of the Study:

• To investigate the role of Pten deletion in specific neuronal populations of the mouse brain.
• To determine if Pten deletion in these neurons leads to behavioral and morphological changes relevant to ASD and macrocephaly.

Main Methods:

• Conditional deletion of the Pten gene in differentiated neuronal populations within the cerebral cortex and hippocampus of mice.
• Behavioral assessments, including social interaction tests and sensory response evaluations.
• Histological and molecular analyses to examine neuronal morphology, synaptic density, and key signaling pathway activation (Akt/mTor/S6k, Gsk3beta).

Main Results:

• Pten deletion in targeted neurons resulted in macrocephaly and neuronal hypertrophy.
• Mutant mice exhibited abnormal social interactions and exaggerated sensory responses, characteristic of ASD-like behaviors.
• Observed neuronal hypertrophy included enlarged and misplaced dendrites and axonal tracts with increased synaptic connections.
• These morphological changes correlated with the activation of the Akt/mTor/S6k pathway and inactivation of Gsk3beta.

Conclusions:

• Conditional deletion of Pten in specific neuronal populations can induce macrocephaly and ASD-relevant behavioral abnormalities.
• Abnormal activation of the PI3K/AKT signaling pathway in neurons is implicated in the observed phenotypes.
• These findings suggest a potential mechanism linking PTEN dysfunction to neurodevelopmental disorders like ASD.