Merab Kokaia

Gene therapy is emerging as a groundbreaking strategy for treating epilepsy, offering new hope to patients who do not respond to conventional medications. Despite advancements in anti‐seizure treatments, nearly 30%–40% of individuals with epilepsy continue to experience uncontrolled seizures, highlighting the urgent need for more effective and long‐lasting solutions. By addressing the underlying causes of epilepsy at the genetic level, gene therapy represents a paradigm shift in treatment. Two key approaches are being explored: (1) activating or supplementing beneficial genes to suppress seizures and (2) silencing harmful genes or pathways that contribute to epilepsy. To achieve these objectives, viral vectors, such as adeno‐associated viruses and lentiviruses, have shown promise in delivering targeted genetic interventions. In parallel, cutting‐edge techniques such as optogenetics, chemogenetics, and clustered regularly interspaced short palindromic repeat‐based gene editing are enhancing the precision of these therapies, enabling greater control over neuronal activity. However, significant challenges exist, including ensuring safe and efficient gene delivery, maintaining long‐term therapeutic effects, and mitigating potential side effects. This review examines recent developments in gene therapy for epilepsy, assessing its potential to deliver targeted, long‐lasting treatments for drug‐resistant epilepsy. By examining current strategies, therapeutic targets, and emerging technologies, it provides insights into the promising future of gene therapy as a transformative tool in epilepsy treatment and summarizes current clinical trials utilizing gene and cell therapy technologies for epilepsy.

Epilepsy is a prevalent neurological disorder characterized by spontaneous recurrent seizures (SRS). Epileptogenesis is a multifaceted pathophysiological process that transforms a normal brain into one prone to chronic seizures. Targeting epileptogenesis is a compelling line of epilepsy therapy. Thus, discovering new drugs that oppose, mitigate, or modify epileptogenesis is a significant challenge in modern neuroscience. Our previous work demonstrated that, in a kainic acid (KA)-induced post-status epilepticus model, 28 days myo-inositol (MI) treatment reduces frequency and duration of motor and electrographic SRS even following cessation of treatment, for the following 4 weeks and identified MI as a promising antiepileptogenic compound To further evaluate the dose-dependent efficacy of MI, we applied the same experimental model using 30 mg/kg (dose used in earlier studies), 60 mg/kg, and 120 mg/kg to assess effects on hippocampal electrographic and motor SRS, as well as KA-induced spatial learning and memory impairment in a Morris water maze test. We found that MI had long-lasting, dose-dependent suppressive effects on behavioral and electrographic manifestations of epileptogenesis and ameliorated spatial learning and memory deficit induced by SE, with 60 mg/kg emerging as the most effective dose. Furthermore, we investigated transcriptomic and epigenetic alterations associated with the optimal MI dose and identified multiple affected pathways in the hippocampus. Interestingly, MI treatment resulted in transcriptomic upregulation and prevention of downregulation of several ion channel subunits, including GRIK3 and GRIN3A (kainate and NMDA receptor subunits) and the sodium channel subunit SCNB4. The obtained data highlight new molecular targets for epilepsy therapy and support the translational potential of MI.

Objective: Inositols play significant roles in biological systems. Myo‐inositol (MI), the most prevalent isomer, functions as an osmolyte and mediates cell signal transduction. Other notable isomers include Scyllo‐inositol (SCI) and D‐Chiro‐inositol (DCHI). Our previous investigations have highlighted MI's potential antiepileptogenic effects, although its exact mechanisms of action during epileptogenesis remain unclear. A critical, unexplored area is how inositols interact with proteins. Additionally, the antiepileptogenic capabilities of SCI and DCHI have yet to be determined. This study seeks to address these gaps.Methods: Inositol interacting proteins were identified by cellular thermal shift assay. Status epilepticus (SE) in rats was induced using kainic acid (KA), followed by a 28‐day treatment with either MI, SCI, DCHI, or saline. The duration and frequencies of behavioral spontaneous recurrent seizures (SRS) were scored for 8 weeks by 24 h video monitoring system. The effects of inositol treatment on spatial learning and memory deficits associated with epileptogenesis were evaluated by Morris water maze test. The changes in protein amounts were studied by Western immunoblotting.Results: We identified several proteins that interact with inositols, noting both commonalities and isomer‐specific associations. For the first time, we demonstrated that the treatment with SCI and DCHI, alongside MI, significantly reduces the frequency and duration of behavioral SRS in a KA‐induced post‐status epilepsy model in rats. This reduction persisted for 4 weeks post‐treatment. Moreover, all three inositol isomers mitigated spatial learning and memory deficits associated with epileptogenesis. Alterations in the inositol interacting proteins: alpha synuclein and 14‐3‐3 theta were further examined 8 weeks post‐SE in the hippocampus and neocortex of rats.Significance: Myo‐inositol, SCI and DCHI interact with a number of proteins involved in different biological pathways. All studied inositol isomers express long‐term beneficial effects on KA‐induced SRS and the associated comorbidities. Inositols can be successfully used in the future for translational research.Plain Language Summary: Epilepsy is a common neurological disorder characterized by spontaneous recurrent seizures and a range of associated comorbidities. The process that leads to the development of epilepsy is called epileptogenesis, and currently, no medication can effectively prevent it. Our study investigated the effects of a group of compounds—myo‐inositol, scyllo‐inositol, and D‐chiro‐inositol—that have potential antiepileptogenic properties on epilepsy induced by kainic acid. We found that: (i) the three inositol isomers share some common target proteins and also have unique ones and (ii) all of them counteract epileptogenesis and the related cognitive impairments.

Despite the availability of new drugs on the clinics in recent years, drug-resistant epilepsy remains an unresolved challenge for healthcare, and one-third of epilepsy patients remain refractory to anti-seizure medications. Gene therapy in experimental models has emerged as effective treatment targeting specific neuronal populations in the epileptogenic focus. When combined with an external chemical activator using chemogenetics, it also becomes an “on-demand” treatment. Here, we evaluate a targeted and specific chemogenetic therapy, the PSAM/PSEM system, which holds promise as a potential candidate for clinical application in treating drug-resistant epilepsy. We show that the inert ligand uPSEM⁸¹⁷, which selectively activates the chloride-permeable channel PSAM⁴-GlyR, effectively reduces the number of depolarization-induced action potentials in vitro. This effect is likely due to the shunting of depolarizing currents, as evidenced by decreased membrane resistance in these cells. In organotypic slices, uPSEM⁸¹⁷ decreased the number of bursts and peak amplitude of events of spontaneous epileptiform activity. Although administration of uPSEM⁸¹⁷ in vivo did not significantly alter electrographic seizures in a male mouse model of temporal lobe epilepsy, it did demonstrate a strong trend toward reducing the frequency of interictal epileptiform discharges. These findings indicate that PSAM⁴-GlyR-based chemogenetics holds potential as an anti-seizure strategy, although further refinement is necessary to enhance its efficacy.