Focal Post-natal Deletion of TSC2 Causes Epilepsy
Abstract number :
1.024
Submission category :
1. Basic Mechanisms / 1B. Epileptogenesis of genetic epilepsies
Year :
2023
Submission ID :
460
Source :
www.aesnet.org
Presentation date :
12/2/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Candi LaSarge, PhD – Cincinnati Children's Hospital
Carlie McCoy, BS – Division of Neurosurgery – Cincinnati Children's Hospital; Mary Dusing, BS – Dept of Anesthesia – Cincinnati Children's Hospital; Steve Danzer, PhD – Dept of Anesthesia – Cincinnati Children's Hospital
Rationale:
Epilepsy is one of the most common neurological symptoms in patients with tuberous sclerosis complex occurring in approximately 80 percent of affected children. Unfortunately, epilepsy is often refractory. This disorder is also characterized by non-cancerous tumors, intellectual impairment, autism, and neuropsychiatric disorders. It frequently occurs from two-hit germline + somatic mutations to either the TSC1 or TSC2 genes, causing hyperactivation of the mTOR pathway. While numerous animal models have been developed, most use germline or cell type specific mutations, which do not recapitulate the focal nature of patient brain lesions. Here, we describe an approach to introduce focal loss of Tsc2 from cortical excitatory neurons.
Methods:
AAV9-CaMKII-Cre-mCherry (Vector builder, Chicago, IL) was injected into Tsc2fl/fl (027458 - Tsc2< tm1.1Mjg >/J, Jackson Laboratory; males, n=5; females, n=3) and Tsc2wt/wt (males, n=5; females, n=3) pups at postnatal day two for the excision of the loxP-flanked Tsc2 gene. Anesthetized pups received four injections (50nl each) through the skull into the cortex. At eight to twelve weeks old, mice were implanted with cortical electrodes (1.5mm bilateral, 0.5 mm posterior to bregma) for at least one week of 24/7 video-EEG monitoring.
Results:
All focal Tsc2fl/fl knockout (fTsc2 KO) mice had seizures following cortical AAV-Cre injection. Seizures were evident during the first days of recording, strongly suggesting that seizure began prior to EEG implant at eight weeks. Mice averaged 4.16 +/- 0.56 (mean +/- SEM) seizures per day, whereas littermate controls had no seizures (Two-way ANOVA with genotype and sex as factors, main effect of genotype, p< 0.001). There was no effect of sex or interaction between sex and genotype (p=0.852). Seizures lasted on average 42.52 +/- 2.77 seconds. While seizure duration was consistent between mice, there was no evident pattern among daily seizures for individual mice. Histological analyses show increased pS6 in the cortex of fTsc2 KOs compared to controls.
Basic Mechanisms