Cannabidiol anticonvulsant effect is mediated by the PI3Kγ pathway

Area of Science:

• Neuroscience
• Pharmacology
• Molecular Biology

Background:

• The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/Akt)/mechanistic target of rapamycin (mTOR) pathway is implicated in central nervous system (CNS) disorders, including epilepsy.
• The cannabinoidergic system exhibits anticonvulsant properties, potentially mediated by the PI3Kγ signaling pathway.

Purpose of the Study:

• To investigate whether the anticonvulsant and neuroprotective effects of cannabidiol (CBD) are mediated by the PI3Kγ signaling pathway.
• To elucidate the role of PI3Kγ in CBD's mechanism of action in epilepsy.

Main Methods:

• In vitro and in vivo experiments using C57Bl/6 wild-type (WT) and PI3Kγ knockout (PI3Kγ-/-) mice.
• Induction of seizures using pilocarpine microinjection, followed by histological analysis of neurodegeneration, microgliosis, and astrocytosis.
• Glutamate-induced cell death assay in primary hippocampal neuron cultures.

Main Results:

• CBD increased seizure latency and reduced seizure severity in WT mice, effects absent in PI3Kγ-/- mice.
• CBD prevented postictal neurodegeneration, microgliosis, and astrocytosis in WT animals, but not in PI3Kγ-/- mice.
• CBD's in vivo effects were blocked by cannabinoid receptor or mTOR inhibition, and PI3Kγ deficiency/inhibition abolished CBD's neuroprotection in vitro.

Conclusions:

• The PI3Kγ/mTOR signaling pathway is critically involved in the anticonvulsant and neuroprotective effects of CBD.
• Understanding CBD's mechanism via PI3Kγ modulation is crucial for predicting therapeutic efficacy and side effects in epilepsy treatment.
• These findings contribute to the understanding of CBD's action and its potential as an anti-epileptic therapy.