CDKL5 Deficiency Augments Inhibitory Input into the Dentate Gyrus That Can Be Reversed by Deep Brain Stimulation.

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Cognitive impairment is a key feature of CDKL5 deficiency disorder.
• The neural circuit effects of CDKL5 loss remain largely unknown.
• CDKL5 plays a role in neurodevelopmental processes.

Purpose of the Study:

• Investigate the impact of CDKL5 deficiency on synaptic plasticity and neural circuitry.
• Determine the role of CDKL5 in hippocampus-dependent learning and memory.
• Explore potential therapeutic interventions for CDKL5-related cognitive deficits.

Main Methods:

• Studied synaptic plasticity and local circuit activity in the dentate gyrus of Cdkl5 mutant mice (Cdkl5-/- and Cdkl5+/-).
• Assessed hippocampus-dependent learning and memory using multiple behavioral tasks.
• Utilized in vivo and ex vivo electrophysiological recordings.
• Administered gabazine (GABAergic antagonist) and employed forniceal deep brain stimulation.

Main Results:

• CDKL5 haploinsufficiency impaired hippocampus-dependent learning and memory in both male and female mice.
• Loss of CDKL5 reduced long-term potentiation (LTP) and augmented feedforward inhibition in the perforant path to the dentate gyrus.
• Excitatory/inhibitory input to the dentate gyrus was skewed toward inhibition.
• Gabazine injection improved contextual fear memory in Cdkl5-/- mice.
• Forniceal deep brain stimulation rescued memory deficits, restored synaptic plasticity, and relieved feedforward inhibition in Cdkl5+/- mice.

Conclusions:

• CDKL5 is crucial for maintaining the excitatory/inhibitory balance in the dentate gyrus.
• Imbalances in this circuit contribute to cognitive deficits in CDKL5 deficiency disorder.
• Forniceal deep brain stimulation shows promise as a therapeutic approach for CDKL5 deficiency and potentially other neurodevelopmental disorders.