Epilepsy is underpinned by complex disruptions in neural circuitry and glial function, where astrocytes play a pivotal role in maintaining homeostasis and neuroinflammation. Worldwide 65 million people live with epilepsy, and nearly 30% exhibit resistance to conventional anti-seizure treatments. Cognitive comorbidities are a major concern in people with epilepsy, with nearly 50% experiencing working memory deficits and accelerated long-term forgetting of verbal, non-verbal, and autobiographical information, significantly impairing their quality of life. Seizure-induced astrocytic dysregulation may contribute to cognitive deficits in people with epilepsy. Astrocytic adenosine A2A receptor (A2AR) influence memory processes and astrogliosis, and their expression is subject to epigenetic regulation. Seizures trigger adenosine surge capable of inducing epigenetic modifications, yet the molecular and epigenetic landscape of astrocytes in epilepsy-related memory impairment remains unclear. In this project, we aim to assess the impact of chronic seizures on short‑term memory in mice using the novel object recognition test and to characterize associated astrocyte‑specific epigenetic and molecular changes.

All animal experiments were compliant with the European Commission Directive 2010/63/EU (European Convention for the Protection of Vertebrate Animals used for Experimental and Other Scientific Purposes) and the United Kingdom Home office (Scientific Procedures) Act (1986). The project was approved by the University of Warwick’s AWERB (PP1674884) committee and carried out in accordance with local legislation and institutional requirements. Initially, adult (8-10 weeks) C57BL/6 male mice were implanted with hippocampal cannula and EEG electrodes under isoflurane anesthesia. Two weeks after the surgical recovery, we induced epilepsy in mice through intrahippocampal kainic acid injection through pre-installed intrahippocampal cannula. Five weeks after epilepsy induction epileptic (n=7) and sham control (n=6) mice were tested for short-term memory using the novel object recognition test. To evaluate epigenetic contributions, we performed assay for transposase-accessible chromatin (ATAC)-sequencing and epigenomic profiling of hippocampal astrocytes five weeks post-epilepsy induction, and few days after short term memory testing. Immunohistochemistry assessed hippocampal expression of neuronal activity-regulated cytoskeleton-associated protein (Arc), astrocytic A2AR, connexin-43 (Cx43), and astrocyte morphology in epileptic versus control mice and analysed using Mann-Witney unpaired t-test.

Novel object recognition test revealed epileptic mice exhibit short-term memory impairment. Epileptic mice also exhibit elevated astrocytic A2AR and Cx43 expression, reduced neuronal Arc levels, and pronounced astrocytic morphological changes in memory-related hippocampal regions. Epigenomic analysis corroborated these findings and identified key genes with distinct patterns of chromatin accessibility in astrocytes from epileptic mice. Collectively, our results suggest that seizure-driven alterations in astrocytic morphology and receptor expression, possibly through epigenetic regulation contribute to cognitive dysfunction in epilepsy. Targeting astrocyte-specific epigenetic mechanisms may represent a promising therapeutic strategy for mitigating memory impairment in epilepsy.