STXBP1 Epileptic Encephalopathy – Stxbp1 Mouse Model
Accelerate the availability of targeted therapies that improve the quality of lives of STXBP1 Epileptic Encephalopathy patients using the Stxbp1 mouse model
Stxbp1 Mouse Model Key Characteristics
Epileptic encephalopathies are defined as syndromes characterized by often drug-resistant seizures along with developmental delays or loss of developmental skills occurring due to sporadic (de novo) mutations. In line, de novo mutations in the STXBP1 gene (also known as Munc18-1) lead to the development of STXBP1 epileptic encephalopathy, characterized by infantile epilepsy, intellectual disability, and can include signs of autism spectrum disorders. To test the efficacy of novel therapies or disease-modifying treatments for STXBP1 epileptic encephalopathy, multiple research models can be used.
In line, the symptoms observed in STXBP1 patients can be mimicked using InnoSer’s Stxbp1 +/- mouse model. The Stxbp1 mice have a heterozygous loss of STXBP1 gene, providing a valid preclinical research model for STXBP1 haploinsufficiency. The reduction in STXBP1 protein recapitulates cognitive impairments, behavioral disturbances such as anxiety, and epileptic-like activity (spike-wave discharges [SWDs]). Similar to patients, both SWDs and motor deficits are frequently detected by us via wireless EEG, video, and accelerometer recordings in freely moving Stxbp1 +/- mice.
✓ Floxed null Stxbp1 mouse model maintained on a pure C57BL/6J genetic background.
✓ Model is extensively characterized, peer-reviewed, and published (Kovačević et al. 2018).
✓ Robust and reproducible cognitive impairment and behavioural disturbances.
✓ Epileptic-like activity in electroencephalography (EEG), and muscle twitches detected in electromyography (EMG).
✓ Anti-epileptic drugs Levetiracetam and Lamotrigine reduce epileptic-like activity, as detected by EEG.
✓ On-site breeding and biotechnical expertise at InnoSer allow efficacy testing of gene-targeting interventions as early as post-natal day 1 (PND1).
Take advantage of InnoSer’s expertise, flexibility, and collaborative approach for your research. We support you in identifying new drugs or applications, characterizing their pharmacological properties, and conducting safety and efficacy testing with state-of-the-art readout capabilities and histopathological analysis.
InnoSer’s neurology expert team possesses relevant experience in working with multiple therapy types.
Your STXBP1 Research Starts Here.
View study timelines, recommended readouts, and example data featuring behavioral and EEG tests in the Stxbp1 mouse model.
Stxbp1 Mouse Model Sample Data
In freely moving Stxbp1+/- mice with wireless EEG recording technology, we detect epileptic-like spike-wave discharges (SWD) that are automatically quantified.
These SWDs occasionally coincide with twitches that can be seen on video and are automatically detected by an accelerometer.
Stxbp1 +/- mice mimic cognitive impairments typically observed in STXBP1 epileptic patients that can be detected using a fear conditioning assay
Fear conditioning is a widely used test that measures aversive memory. In contextual fear conditioning, mice learn to pair an unconditioned stimulus with an aversive context. The so-called freezing response of the mouse is monitored to assess the extent to which the unconditioned stimulus is paired with the context. This test is both a measure of anxiety and cognition (learning and memory).
Stxbp1 +/- mice aged from 16 weeks to 20 weeks show stable epileptic-like phenotype.
Average frequency of SWDs per hour in the Stxbp1 +/- mice assessed over a period of several weeks (mean ± SEM).
The epilepsy-like phenotype in Stxbp1 +/- mice is suppressed with standard of care AEDs Levetiracetam and Lamotrigine.
Average frequency of detected SWDs during 6 hours of video recording following administration of saline, Levetiracetam (50 mg/kg, i.p,) and Lamotrigine (50 mg/kg, i.p.) (**P<0.01 saline vs Levetiracetam; ***P<0.001 saline vs Lamotrigine).
Stxbp1 Mouse Model Readouts
Biological Readouts
Test the efficacy of your treatments with the following biological readouts:
- Wireless electroencephalogram (EEG) to detect epileptic-like events (spike wave discharges; SWD)
- Wireless electromyography (EMG) of neck muscle to detect twitches and jumps
- Tissue collection for biomarker analyses
- Immunohistochemical analyses of neural activation (c-Fos)
Our Team’s Featured Publications
- Kovacevic, J., Maroteaux, G., Schut, D., Loos, M., Dubey, M., Pitsch, J., Remmelink, E., Koopmans, B., Crowley, J., Cornelisse, L. N., Sullivan, P. F., Schoch, S., Toonen, R. F., Stiedl, O., & Verhage, M. (2018). Protein instability, haploinsufficiency, and cortical hyper-excitability underlie STXBP1 encephalopathy. Brain : a journal of neurology, 141(5), 1350–1374. https://doi.org/10.1093/brain/awy046
The People Behind Your Research
Sofie Carmans, PhD
Principal Scientist Neurology
Thomas Vogels, PhD
Principal Scientist Neurology
Frequently Asked Questions
What is the Stxbp1 mouse model?
The Stxbp1 mouse model is a preclinical research model used to mimic STXBP1 haploinsufficiency that is frequently observed in STXBP1-related encephalopathies which are a group of severe neurodevelopmental disorders characterized by early-onset epilepsy, developmental delay and cognitive impairment.
Offered by InnoSer, this model enables researchers to evaluate the efficacy of novel therapeutic strategies targeting STXBP1-related disorders.
As described by Kovačević et al. (2022, Brain), mutant Stxbp1 mice were generated by first flanking exons 2–6 of one allele of the Stxbp1 gene with loxP sites in mice maintained on a pure C57BL/6J background. These mice were then crossed with Cre-deleter mice, leading to a germline excision of the floxed exons, resulting in mice heterozygous for a null allele (Stxbp1cre/+). The resulting mice were further bred on a pure C57BL/6J background, generating a stable Stxbp1+/− mouse line without flanking gene variations, in turn exhibiting a permanent loss of one functional copy of the Stxbp1 gene. Therefore, the Stxbp1 +/- mice effectively model the STXBP1 haploinsufficiency that is frequently observed in patients diagnosed with STXBP1-related disorders.
To learn more about InnoSer’s capabilities in preclinical STXBP1 research, download our leaflet or get in touch with our scientific team.
What types of therapeutics can be tested in InnoSer’s Stxbp1 mouse model?
InnoSer’s Stxbp1 mouse model is suitable for evaluation of nonclinical efficacy of novel therapeutics ranging from small molecule drugs aimed at for e.g., modifying seizure activity or cognitive symptoms, to gene therapies (e.g., AAV-mediated) designed to restore STXBP1 function.
Thanks to on-site breeding capabilities, therapeutic interventions can be administered as early as postnatal day 1 (PND1), enabling the assessment of early developmental treatment windows, which may be of particular importance when testing gene therapies aimed at restoring STXBP1 function.
InnoSer has broad capabilities working with gene therapies, supporting multiple delivery routes (i.e., retro-orbital, IV, and ICV) as well as dosing strategies. Learn more about our gene therapy capabilities here.
Has InnoSer documented the natural history of Stxbp1 mice?
Yes, InnoSer’s expert neuroscience team has extensively characterized the natural history of the Stxbp1 mouse model to better understand the model’s disease progression and identify optimal windows for therapeutic intervention. Our longitudinal studies have shown:
- Consistent phenotype: Following EEG measurements, which includes the set-up of wireless EEG electrodes in Stxbp1, our studies have shown that Stxbp1 +/- mice show no phenotypic changes (for e.g., in cognitive tasks) meaning that behavioral phenotyping can take place both before and/or after EEG measurements, allowing you to obtain more in-depth information in same cohort of mice.
This flexibility enables interested researchers to consider multiple study design options, including: Behavior testing before dosing, followed by EEG measurement; Baseline EEG prior to dosing, then final EEG and behavioral assessments (in any order); Studies focusing solely on EEG and/or behavioral endpoints.
- Sex differences: Our team has detected no significant differences between male and female Stxbp1 mice, therefore, due to the consistent phenotypes observed mixed sex animals are typically used and recommended for studies.
- Epileptic-like phenotype: Our team has confirmed that Stxbp1 mice exhbit stable and robust spike-wave discharges (SWDs) from at least 10 weeks of age, with available published datasets showing longitudinal EEG recordings from 16 to 20 weeks (latest time point measured to date), supporting reliable assessment of epileptic-like phenotype over a period of time. View the data sets here.
- Cognitive deficits: Our team has shown that Stxbp1 mice display lower freezing response during the fear conditioning test, suggesting impaired learning and memory performance in young Stxbp1 mice. However, as Fear Conditioning can be performed only once due to learning effects, we recommend discussing closely with our study experts at which age to include this readout.
- Automated home-cage behavior (PhenoTyper): The PhenoTyper system allows the assessment of several aspects of animal behavior over a period of a few days, without human interference. We have previously detected a decreased number of OnShelter visits in Stxbp1 mice.
- Motor deficits: Motor deficits have been observed in the Stxbp1 mouse model and are currently evaluated by our expert scientific teams. Subscribe to our newsletter to get the newest research updates and developments about the Stxbp1 mouse model.
What are spike-wave discharges (SWDs) and how does InnoSer quantify them in the Stxbp1 mouse model?
Spike-wave discharges (SWDs) are brief episodes of synchronous brain activity seen on wireless EEG in Stxbp1 mice, representing epilepsy-like phenotype, which can be quantified in order to provide measurement of nonclinical treatment efficacy for STXBP1-related disorders.
While patients diagnosed with STXBP1-related disorders exhibit early onset infantile spasms, with focal and multifocal EEG activity and/or suppression-burst patterns (Kovacevic et al., 2022 Brain), the Stxbp1 mice mimic only some of these clinical features, including sudden myoclonic jerks (which we usually refer to as “twitches”) observed typically during sleep and sudden SWDs detectable via EEG.
Experts at InnoSer have developed a machine learning-based pipeline trained on over 5,000 SWD patterns, enabling automated analysis of up to 18 hours of continuous EEG data. As the SWDs occasionally coincide with twitches and jumps, video recording and accelerometer is combined to enable more in-depth analysis of the treatment efficacy.
Learn more about the set-up utilised to detect SWDs in the Stxbp1 mouse model here.
Does InnoSer perform baseline EEG recordings in the Stxbp1 mouse model?
Yes, InnoSer can perform baseline EEG recordings in the Stxbp1 mouse model as part of nonclinical efficacy studies to help optimise experimental study designs. Performing baseline EEG helps with:
- SWD variability screening: The presence of spontaneous spike-wave discharges (SWDs) can vary substantially between individual Stxbp1+/- mice. Baseline EEG helps identify this variability early.
- Stratified randomization: Based on SWD levels during baseline, mice are randomized across treatment groups to ensure balanced distribution of high and low SWD phenotypes.
- Increased statistical power: Mice with no or very low SWDs are excluded from further testing, reducing variability and improving sensitivity to treatment effects.
Moreover, whether baseline EEG is performed can further depend on your compound’s administration routes as well. For compounds administered peripherally (e.g., IV), baseline EEG can be easily implemented into your study designs. Treatments that do not pass the blood-brain barrier (e.g., biologics or oligonucleotides) and require direct CNS delivery (e.g., ICV), would typically require more complex study set-up (due to the need of combining EEG electrode implantation with cannula implantation) which need to be discussed with our scientific teams.
Can the seizure-like activity of the Stxbp1 mouse model be suppressed with anti-epileptic drugs (AEDs)?
Yes, the seizure-like activity of InnoSer’s Stxbp1 mouse model can be suppressed with the anti-epileptic drugs (AEDs) levetiracetam and lamotrigine, which are also used in human STXBP1 patients to help manage seizures.
View the data showing a decrease in SWDs following AED treatment in Stxbp1 mice here.
What post-mortem analyses can InnoSer perform in the Stxbp1 mouse model?
InnoSer offers comprehensive post-mortem analyses for the Stxbp1 mouse model to support detailed evaluation of therapeutic effects. These advanced biomarker assessments typically include histopathological examinations to assess levels of c-Fos, but other biomarker analyses using Meso Scale Discovery (MSD) assays in cerebrospinal fluid (CSF) can be explored.
Are Stxbp1 mice readily available at InnoSer for efficacy studies?
Yes, InnoSer maintains a continuous stock of Stxbp1 mouse colonies, meaning that they do not have to be sourced from other laboratories, supporting quick study starts, whilst helping you avoid timeline delays due to quarantining periods. On-site breeding and biotechnical expertise at InnoSer allow efficacy testing of gene-targeting interventions as early as post-natal day 1 (PND1).
Reach out to our team to obtain more detailed study timelines now.
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