Ndel1 and Reelin Maintain Postnatal CA1 Hippocampus Integrity

Area of Science:

• Neuroscience
• Cell Biology
• Molecular Biology

Background:

• The maintenance of laminar structures in the postnatal brain is vital for neuronal function.
• Ndel1, a microtubule-associated protein, has been implicated in neurogenesis and neuronal migration.
• Constitutive Ndel1 knockout is embryonic lethal, necessitating conditional knockout models for postnatal studies.

Purpose of the Study:

• To investigate the role of Ndel1 in maintaining the integrity of postnatal brain structures, specifically the CA1 region of the hippocampus.
• To elucidate the relationship between Ndel1, Reelin, and the structural and functional integrity of CA1 pyramidal neurons.

Main Methods:

• Generation of a conditional knockout mouse model lacking Ndel1 in the postnatal brain.
• Analysis of microtubule integrity, dendritic and synaptic morphology, neuronal excitability, and cell dispersion in CA1 pyramidal neurons.
• Assessment of Reelin levels and the effects of Reelin administration in Ndel1 conditional knockout mice.

Main Results:

• Postnatal absence of Ndel1 leads to fragmented microtubules, dendritic and synaptic pathologies, and hyperexcitability in CA1 pyramidal neurons.
• Ndel1 deficiency causes dispersion of CA1 neurons, independent of migration defects, and reduces inhibitory input from interneurons.
• Levels of the glycoprotein Reelin are significantly reduced in the hippocampus of Ndel1 conditional knockout mice.
• Reelin administration ameliorates the observed ultrastructural, cellular, morphological, and anatomical defects in the CA1 region.

Conclusions:

• Ndel1 is essential for maintaining the structural and functional integrity of postnatal CA1 hippocampal neurons.
• Ndel1 and Reelin act in concert to preserve CA1 integrity.
• Dysregulation of Ndel1 and Reelin may contribute to neurological disorders characterized by hippocampal dysfunction.