Biology subjects

Perez-Reyes, E.

Publications and source records attributed to Perez-Reyes, E..

6 recordsLinked to original sources

bioRxiv2026

Gene therapy with doxycycline-controlled expression of human Kv1.1 reduces neuronal excitability and increases sociability of Scn2a-deficient mice

Genetic loss-of-function (LoF) variants in SCN2A, a gene encoding the voltage-gated sodium channel Nav1.2, have been identified as one of the foremost monogenic causes of autism spectrum disorder (ASD). ASD encompasses a broad spectrum of behavioral phenotypes, with impaired sociability as a core characteristic. We have established Scn2a-deficient mice (Scn2agt/gt) to model Scn2a-related ASD and found that this model recapitulates social impairment, exhibiting severe social deficits. Scn2agt/gt mice exhibit neuronal hyperexcitability and a marked global reduction in potassium channel expression, which plays a crucial role in maintaining the resting membrane potential and repolarizing neurons after an action potential. Among these downregulated potassium channels, potassium voltage-gated channel subfamily A member 1 (Kv1.1) was one of the most affected. To explore whether Kv1.1 could be a potential therapeutic target in SCN2A-related ASD, we evaluated the in vivo efficacy of a genetic construct driven by the CaMKII promoter that allows for exogenous expression of human Kv1.1 (hKv1.1) in principal neurons. In Scn2agt/gt mice, we found that hKv1.1 expression normalizes neuronal hyperexcitability. Importantly, doxycycline-induced hKv1.1 expression enhances sociability in Scn2a-deficient mice without influencing social behavior in wild-type mice, and this effect was reversed upon doxycycline withdrawal. Overall, we demonstrate the successful use of an inducible AAV-mediated gene delivery system to supplement hKv1.1 expression to mitigate neuronal hyperexcitability and ameliorate social impairments in a mouse model of SCN2A-related ASD. These findings highlight the contribution of Kv1.1 to SCN2A-associated pathophysiology and its potential as a therapeutic target for severe social deficits.

neuroscience↗

bioRxiv2026

Seizures induce c-fos expression in a subset of astrocytes, termed fostrocytes, that dampen subsequent seizures

Objective: The original goal was to map neuronal circuits activated by spontaneous seizures in models of temporal lobe epilepsy. Studies used the c-fos driven TRAP2 system, which has been used successfully to label neurons after seizures. Unexpectedly, astrocytes were also labeled, then shown to express c-fos in a sustained manner after seizures. The role of these so-called fostrocytes in spontaneous seizures was studied using novel Cre-dependent AAVs. Methods: Studies used a homozygous mouse line produced by crossing TRAP2 Cre-driver mice with the Ai9 Cre-reporter line. Seizures were induced using electrical stimulation, kainic acid, or pilocarpine. Cre-dependent AAVs used the GFAP promoter to drive expression of either the catalytic A chain of diphtheria toxin (DTA), GFP, or empty vector. Spontaneous seizures were continuously recorded using EEG. Results: Discrete seizures in naive mice evoked transient c-fos expression in all astrocytes, while status epilepticus evoked a higher and sustained level of c-fos expression. Timing the activation of the TRAP2 system allowed specific labeling of the subset of astrocytes with high c-fos expression. These cells were colocalized with established astrocyte markers, showed reactive astrocyte morphology, and were selectively labeled by GFAP-driven Cre-dependent AAVs. Ablation of fostrocytes in spontaneously seizing mice increased seizure frequency. Significance: Next-generation sequencing studies have revealed a great diversity of astrocyte subtypes, identifying clusters with up-regulated c-fos expression in patients with neurological disorders. In conclusion, these studies suggest that therapies that augment the activity of c-fos expressing astrocytes would have anti-seizure activity.

neuroscience↗

bioRxiv2025

Microglia and its P2RY12 Receptors Regulate Seizure Severity

Microglia have emerged as possible regulators of seizures with previous approaches employed being insufficiently selective of microglial-specific contributions. To more definitely determine microglial roles in seizure severity, we used the recently developed genetic microglial-deficient Csf1r{Delta}FIRE/{Delta}FIRE (FIRE KO) mouse model. In this model, mice lack microglia but retain brain border associated macrophages (BAMs). Using two experimental seizure paradigms with either a chemoconvulsant or electrical stimulation, we confirm that a microglial deficiency exacerbates seizures, reduces survival and facilitates the likelihood of developing spontaneous recurrent seizures, indicating that microglia constrain seizure activity across different seizure paradigms. To gain insights into molecular regulators of seizure severity under microglial regulation, we examined P2RY12 contributions and demonstrate that a loss of microglial P2RY12 increased seizure severity in both global and microglial-specific knockout mice indicating that microglia suppress seizure severity in chemoconvulsive models through P2RY12 signaling. During seizures, P2RY12-deficient microglia displayed altered process complexity, accompanied by increased neuronal activation and reduced inhibitory tone. These results link impaired microglial responses to heightened seizure susceptibility and network excitability. Together, our findings establish microglia as protective regulators of seizure activity and identify P2RY12 signaling as a critical mediator of microglia protective actions.

neuroscience↗

bioRxiv2025

Gene therapies alleviate absence epilepsy associated with Scn2a deficiency in DBA/2J mice

Mutations in the voltage-gated sodium channel gene SCN2A, which encodes the NaV1.2 channel, cause severe epileptic seizures. Patients with SCN2A loss-of-function (LoF) mutations, such as protein-truncating mutations, often experience later-onset and drug-resistant epilepsy, highlighting an urgent unmet clinical need for new therapies. We previously developed a gene-trap Scn2a (Scn2agt/gt) mouse model with a global NaV1.2 reduction in the widely used C57BL/6N (B6) strain. Although these mice display multiple behavioral abnormalities, EEG recordings indicated only mild epileptiform discharges, possibly attributable to the seizure-resistant characteristics associated with the B6 strain. To enhance the epileptic phenotype, we derived congenic Scn2agt/gt mice in the seizure-susceptible DBA/2J (D2J) strain. Notably, we found that these mice exhibit prominent spontaneous absence seizures, marked by both short and long spike-wave discharges (SWDs). Restoring NaV1.2 expression in adult mice substantially reduced their SWDs, suggesting the possibility of SCN2A gene replacement therapy during adulthood. RNA sequencing revealed significant alterations in gene expression in the Scn2agt/gt mice, in particular a broad downregulation of voltage-gated potassium channel (KV) genes, including KV1.1. The reduction of KV1.1 expression was further validated in human cerebral organoids with SCN2A deficiency, highlighting KV1.1 as a promising therapeutic target for refractory seizures associated with SCN2A dysfunction. Importantly, delivery of exogenous human KV1.1 expression via adeno-associated virus (AAV) in D2J Scn2agt/gt mice substantially reduced absence seizures. Together, these findings underscore the influence of mouse strain on seizure severity and highlight the potential of targeted gene therapies for treating SCN2A deficiency-related epilepsies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=91 SRC="FIGDIR/small/657652v1_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@35374eorg.highwire.dtl.DTLVardef@1c22197org.highwire.dtl.DTLVardef@2b4582org.highwire.dtl.DTLVardef@e06e68_HPS_FORMAT_FIGEXP M_FIG C_FIG In briefScn2a deficiency leads to absence seizures in D2J mice and neuronal hyperexcitability with compensatory KV reduction; restoring NaV1.2 or introducing human KV1.1 reduces seizure burden. HighlightsO_LIScn2a deficiency induces robust absence seizures in the DBA/2J but not the C57BL/6N strain. C_LIO_LICortical neurons in adult DBA/2J mice with Scn2a deficiency exhibit intrinsic hyperexcitability. C_LIO_LISevere Scn2a deficiency leads to downregulation of multiple potassium channel genes. C_LIO_LIGenetic restoration of NaV1.2 expression alleviates spike-wave discharges (SWDs). C_LIO_LIAAV-mediated human KV1.1 delivery substantially reduced absence seizures, demonstrating the therapeutic potential of targeted gene therapy. C_LI

neuroscience↗

bioRxiv2023

Microglia play beneficial roles in multiple experimental seizure models.

Seizure disorders are common, affecting both the young and the old. Currently available antiseizure drugs are ineffective in a third of patients and have been developed with a focus on known neurocentric mechanisms, raising the need for investigations into alternative and complementary mechanisms that contribute to seizure generation or its containment. Neuroinflammation, broadly defined as the activation of immune cells and molecules in the central nervous system (CNS), has been proposed to facilitate seizure generation, although the specific cells involved in these processes remain inadequately understood. The role of microglia, the primary inflammation-competent cells of the brain, is debated since previous studies were conducted using approaches that were less specific to microglia or had inherent confounds. Using a selective approach to target microglia without such side effects, we show a broadly beneficial role for microglia in limiting chemoconvulsive, electrical, and hyperthermic seizures and argue for a further understanding of microglial contributions to contain seizures.

neuroscience↗

bioRxiv2018

LMO7 deficiency reveals the significance of the cuticular plate for hearing function

Sensory hair cells, the mechanoreceptors of the auditory and vestibular system, harbor two specialized organelles, the hair bundle and the cuticular plate. Both subcellular structures have adapted to facilitate the remarkable sensitivity and speed of hair cell mechanotransduction. While the mechanosensory hair bundle is extensively studied, the molecules and mechanisms mediating the development and function of the cuticular plate are poorly understood. The cuticular plate is believed to provide a rigid foundation for stereociliar pivot movements, but specifics about its function, especially the significance of its integrity for long-term maintenance of hair cell mechanotransduction, are not known. In this study, we describe the discovery of a hair cell protein called LIM only protein 7 (LMO7). In the hair cell, LMO7 is specifically localized in the cuticular plate. Lmo7 KO mice suffer multiple deficiencies in the cuticular plate, including reduced filamentous actin density and abnormal length and distribution of stereociliar rootlets. In addition to the cuticular plate defects, older Lmo7 KO mice develop abnormalities in inner hair cell stereocilia. Together, these defects affect cochlear tuning and sensitivity and give rise to late-onset progressive hearing loss.

neuroscience↗