Biology subjects

Bass, J. S.

Publications and source records attributed to Bass, J. S..

5 recordsLinked to original sources

bioRxiv2025

EGR3 Deletion Rescues Developmental and Epileptic Encephalopathy in Kcna1-null Mice

KCNA1 encodes the -subunit of the voltage-gated potassium channel KV1.1. Mutations in KV1.1s pore domain result in developmental and epileptic encephalopathy (DEE), where early life seizures and a culprit lesion synergistically disrupt neurodevelopmental trajectories, resulting in intellectual disability that often presents with disturbances in sleep, sociability and sensory processing. Abnormalities in the subcellular localization of Kv1.1, via mutations in/autoantibodies against LGI1 and CNTNAP2, also give rise to syndromes of epilepsy and neuropsychiatric impairment. Mice with deletions of Kcna1("-/-") display spontaneous seizures at 2-3 weeks of age and premature mortality. In this study, we applied instrumented home-cage monitoring to examine how aberrations in KCNA1 expression may result in pervasive alterations in spontaneous behavior. Compared to wildtype, Kcna1-/- mice displayed a robust multifaceted behavioral syndrome featuring marked nocturnal hyperactivity, insomnia, reduced sheltering, fragmented feeding/drinking rhythms, sensory over-responsivity and diminished wheel-running. In identical recordings, Kcna1+/- mice only displayed increased sheltering, Lgi1+/- mice displayed mild insomnia and Cntnap2-/- mice showed home-cage hypoactivity. Kcna1 loss in parvalbumin-positive interneurons (Pv-Cre) resulted in a subtle phenocopy, with mild insomnia accompanied by reduced sheltering behavior, while similar deletions in forebrain pyramidal neurons (Emx1-Cre) or dopaminergic neurons (DAT-Cre) were asymptomatic. Adult-onset conditional deletions of Kcna1 also produced only mild insomnia 6 weeks later. To survey the molecular landscape in Kcna1-/- mice, we conducted a mass spectrometry proteomic analysis of dissected hippocampal tissue (a predominant seizure onset zone and where astrogliosis is observed). This revealed significant upregulations in BDNF (brain-derived neurotrophic factor) and the immediate early transcription factor EGR3 (early growth response-3), which is necessary for the induction of BDNF following electroconvulsive seizures. Heterozygous or homozygous deletions of Egr3 in Kcna1-/- mice resulted in significant survival prolongation, a partial neurobehavioral rescue, and a significant improvement in the frequency of spontaneous seizures and spreading depolarization events. These clinical improvements were associated with an amelioration of BDNF induction, hippocampal astrogliosis and proteomic disturbances. Together, these data illustrate how an ion channel that governs excitability at millisecond scales also shapes the spatiotemporal structure of spontaneous behavior at meso- or macroscopic time scales. Our results provide a model and a set of precision endpoints to understand how ictal and interictal features of DEE may be ameliorated by inhibiting the long-term downstream transcriptional alterations imparted by early life seizures.

neuroscience↗

bioRxiv2023

Clinicopathologic Dissociation: Robust Lafora Body Accumulation in Malin KO Mice Without Observable Changes in Home-cage Behavior

Lafora Disease (LD) is a syndrome of progressive myoclonic epilepsy and cumulative neurocognitive deterioration caused by recessively inherited genetic lesions of EPM2A (laforin) or NHLRC1 (malin). Neuropsychiatric symptomatology in LD is thought to be directly downstream of neuronal and astrocytic polyglucosan aggregates, termed Lafora bodies (LBs), which faithfully accumulate in an age-dependent manner in all mouse models of LD. In this study, we applied home-cage monitoring to examine the extent of neurobehavioral deterioration in a model of malin-deficient LD, as a means to identify robust preclinical endpoints that may guide the selection of novel genetic treatments. At 6 weeks, [~]6-7 months and [~]12 months of age, malin deficient mice ("KO") and wild type (WT) littermates underwent a standardized home-cage behavioral assessment designed to non-obtrusively appraise features of rest/arousal, consumptive behaviors, risk aversion and voluntary wheel-running. At all timepoints, and over a range of metrics that we report transparently, WT and KO mice were essentially indistinguishable. In contrast, within WT mice compared across timepoints, we identified age-related nocturnal hypoactivity, diminished sucrose preference and reduced wheel-running. Neuropathological examinations in subsets of the same mice revealed expected age dependent LB accumulation, gliosis and microglial activation in cortical and subcortical brain regions. At 12 months of age, despite the burden of neocortical LBs, we did not identify spontaneous seizures during an electroencephalographic (EEG) survey, and KO and WT mice exhibited similar spectral EEG features. Using an in vitro assay of neocortical function, paroxysmal increases in network activity (UP states) in KO slices were more prolonged at 3 and 6 months of age, but were similar to WT at 12 months. KO mice displayed a distinct response to pentylenetetrazole, with a greater incidence of clonic seizures and a more pronounced post-ictal suppression of movement, feeding and drinking behavior. Together, these results highlight a stark clinicopathologic dissociation in a mouse model of LD, where LBs accrue substantially without clinically meaningful changes in overall wellbeing. Our findings allude to a delay between LB accumulation and neurobehavioral decline: one that may provide a window for treatment, and whose precise duration may be difficult to ascertain within the typical lifespan of a laboratory mouse.

neuroscience↗

bioRxiv2022

Actigraphic Correlates of Neuropsychiatric Disability in Adult Patients with Focal Epilepsy

Disability in patients with epilepsy (PWE) is multifactorial: beyond seizure frequency/severity, PWE are prone to a range of neuropsychiatric, cognitive, and somatic comorbidities that significantly impact quality of life. In this study, we explored how variations in epilepsy severity and the burden of self-reported somatic/neuropsychiatric symptoms are associated with disruptions to 24h activity patterns (rest-activity rhythms, RARs), determined through wrist accelerometry/actigraphy. Continuous multiday recordings were obtained from 59 adult patients with focal epilepsy (44% male, ages 18-72), who contemporaneously provided responses to a range of validated psychometric instruments to measure the burden of anxiety, depression, sleepiness, and somatic symptoms. As a comparator, we conducted a similar psychometric-actigraphic correlation in 1761 subjects of Hispanic origin (35% male, ages 18-65) from the Study of Latinos (SOL) Sueno Ancillary Study. RARs were analyzed via a sigmoidally-transformed cosine model (quantifying RAR amplitude, steepness, acrophase and robustness) and non-parametric measures to estimate RAR stability, fragmentation, and sleep. Compared with age- and sex-matched SOL subjects, RARs from PWE subjects featured a significantly diminished amplitude, a wider rest phase and significantly more total daily sleep. Within PWE, similar RAR distortions were associated with seizure intractability and/or anticonvulsant polytherapy. In contrast, high anxiety, depression, and somatic symptom scores were associated with diminished RAR robustness and a delayed acrophase. We applied the complete SOL Sueno database to train logistic regression models to dichotomously classify anxiety, depression and sleepiness symptoms using age, sex, body mass index and a range of non-collinear RAR parameters. When tested on PWE, these models predicted prevalent anxiety and depression symptoms with modest success (accuracy [~]70%) but failed to predict subjective sleepiness. Together, these results demonstrate that RAR features may vary with depression and anxiety symptoms in ambulatory patients with focal epilepsy, potentially offering a set of objective wearable-derived endpoints to adjunct routine clinical care and drug/device treatment trials. With larger actigraphic-psychometric datasets in PWE, we may identify RAR signatures that can more precisely distinguish between variations in seizure risk, the burden of anticonvulsant therapy and prevalent mood/anxiety symptoms.

neuroscience↗

bioRxiv2022

On the Mental Status of Stargazer Mice

In many childhood-onset genetic epilepsies, seizures are accompanied by neurobehavioral impairments and motor disability. In the Stargazer mutant mouse, genetic disruptions of Cacng2 result in absence-like spike-wave seizures, cerebellar gait ataxia and vestibular dysfunction. Here, we combine videotracking and instrumented home-cage monitoring to resolve the neurobehavioral facets of the murine Stargazer syndrome. We find that despite their gait ataxia, stargazer mutants display horizontal hyperactivity and variable rates of repetitive circling behavior. While feeding rhythms, circadian or ultradian oscillations in activity are unchanged, mutants exhibit fragmented sleep bouts, atypical licking dynamics and lowered sucrose preference. Mutants also display an attenuated response to visual and auditory home-cage perturbations, together with profound reductions in voluntary wheel-running. Our results reveal that the seizures and ataxia of Stargazer mutants occur in the context of a more pervasive behavioral syndrome with elements of encephalopathy, repetitive behavior and anhedonia. These findings expand our understanding of the function of Cacng2/CACNG2, variants in which have been identified in patients with bipolar disorder and schizophrenia.

neuroscience↗

bioRxiv2020

On the Digital Psychopharmacology of Valproic Acid in Mice

ObjectiveAntiepileptic drugs (AEDs) require daily ingestion for maximal seizure prophylaxis. Adverse psychiatric consequences of AEDs present as: (i) reversible changes in mood, anger, anxiety and/or irritability that often necessitate drug discontinuation, and (ii) autism and/or cognitive/psychomotor developmental delays following fetal exposure. Technical advances in quantifying naturalistic rodent behaviors may provide sensitive preclinical estimates of AED psychiatric tolerability and neuropsychiatric teratogenicity. MethodsUsing instrumented home-cage monitoring, we assessed how valproic acid (VPA, dissolved in sweetened drinking water) alters home-cage behavior in adult C57BL/6J mice and in the adult offspring of VPA-exposed breeder pairs. By utilizing a pup open field assay, we also examined how prenatal VPA exposure impacts early spontaneous exploratory behavior. ResultsAt 500-600mg/kg/d, chronic VPA produced hyperphagia and increased wheel-running without impacting sleep, activity and measures of risk aversion. When applied chronically to breeder pairs of mice, VPA prolonged the latency to viable litters without affecting litter size. Two-week old VPA-exposed pups displayed open field hypoactivity without alterations in thigmotaxis. As adults, prenatal VPA-exposed mice displayed active state fragmentation, hypophagia and increased wheel running, together with subtle alterations in home-cage dyadic behavior. InterpretationThrough automated home-cage assessments of C57BL/6J mice, we capture an ethologically centered psychopharmacological profile of enterally administered VPA that is aligned with human clinical experience. By characterizing the effects of pangestational VPA exposure, we discover novel murine expressions of pervasive neurodevelopment. Incorporating rigorous comprehensive assessments of neuropsychiatric tolerability may inform the design of future AEDs with improved neuropsychiatric safety profiles, both for patients and their offspring.

neuroscience↗