Drug-inducible Gene Therapy Effectively Reduces Spontaneous Seizures in Kindled Rats but Creates Off-target Side Effects in Inhibitory Neurons
Abstract number :
3.037
Submission category :
1. Basic Mechanisms / 1D. Mechanisms of Therapeutic Interventions
Year :
2023
Submission ID :
832
Source :
www.aesnet.org
Presentation date :
12/4/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Edward Perez-Reyes, PhD – University of Virginia
Iuliia Vitko, PhD – University of Virginia; Kathryn Blair, MD – University of Virginia; Ronald Gaykema, PhD – University of Virginia; Madison Failor, BA – University of Virginia; Jennifer San Pietro, BA – University of Virginia; Deblina Dey, PhD – University of Virginia; Ruth Stornetta, PhD – University of Virginia; John Williamson, PhD – University of Virginia; Jaideep Kapur, MD, PhD – Professor, Neurology, University of Virginia; Kyle Sullivan, PhD – Oak Ridge National Laboratory
Rationale:
Over a third of patients with temporal lobe epilepsy (TLE) are not effectively treated with current anti-seizure drugs. This has spurred efforts to develop gene therapies for TLE. Direct injection of adeno-associated viral vectors (AAV) into the brain or into intrathecal spaces have been shown to be safe and viable approaches for delivering gene therapies. However, to date, AAV expression of therapeutic genes have not been regulated. Moreover, a common property of antiepileptic drugs is a narrow therapeutic window between seizure control and side effects. Therefore, a long-term goal is to develop drug-inducible gene therapies that can be regulated by clinically relevant drugs.
Methods:
In this study, a first generation doxycycline-regulated gene therapy that delivered an engineered version of the leak potassium channel Kcnk2 (TREK-M) was injected into the hippocampus of male rats. An EEG recording headset was affixed to the skull. Rats were electrically stimulated until kindled. EEG was monitored 24/7.
Results:
Electrical kindling revealed an important side effect, as even low expression of TREK-M in the absence of doxycycline was sufficient to cause rats to develop spontaneous recurring seizures. Treating the epileptic rats with doxycycline successfully reduced spontaneous seizures. Localization studies of neurons infected with AAV suggest seizures were caused by expression in hippocampal GABAergic inhibitory neurons. In contrast, doxycycline increased the expression of TREK-M in excitatory neurons, thereby reducing seizures through net inhibition of firing.
Conclusions:
These studies demonstrate that drug-inducible gene therapies are effective in reducing spontaneous seizures in rats, and highlight the importance of testing for side effects with pro-epileptic stressors such as electrical kindling. These studies also show the importance of evaluating the location and spread of AAV-based gene therapies in preclinical studies.
Funding:
Supported by NIH grants NS097726 and NS040337.
Basic Mechanisms