elevated plus maze test in an angelman syndrome mouse model

Validierung eines Mausmodells des Angelman-Syndroms mit Hilfe von Verhaltenstests

Angelman syndrome (AS) is a rare neurodevelopmental disease. The most common genetic origin of AS is a large deletion of the 15q11-q13 region of the maternally-derived chromosome, which is found in nearly 74% of patients1. Deletion of this region causes the loss of UBE3A, the main causative gene of AS that encodes an E3 ubiquitin ligase. The paternal allele of the UBE3A gene in neurons is silenced in a process known as imprinting. As a consequence, paternal imprinting of the gene allows only maternal expression in the central nervous system (CNS)2. Therefore, UBE3A gene deletion from the maternally-derived chromosome leads to the development of AS symptoms. In humans, AS manifests at around 6 months of age, with developmental retardation that persists throughout all developmental stages and results in severe debilitating symptoms in affected individuals3,4. The core symptoms of the disorder include the deficit of fine and gross motor skills, including jerky ataxic gait, serious speech impairment, and intellectual disability. Approximately 80% of AS patients also suffer from sleep disturbances and epilepsy. To date, the only available treatment are symptomatic drugs, which reduce epileptic seizures and improve sleep quality1. Therefore, the development of robust animal models with reproducible behavioral phenotypes alongside refined phenotyping analysis will be essential to elucidate the pathophysiological mechanisms of the disorder and discover effective medications and treatments.
The complexity of the human disorder affecting the CNS demands model organisms to possess a comparable genome, physiology, and behavior. Mice are popular as a model organism due to their short reproductive cycle, small size, and relative ease of DNA modification. In 1984, Paul Willner proposed three basic disease model validation criteria: the construct, face, and predictive validity, which are used to determine the model&#39;s value5. Simply, construct validity reflects the biological mechanisms responsible for the disorder development, face validity recapitulates its symptoms, and predictive validity describes the model response to therapeutic drugs.
To adhere to the above principles, we have chosen the most common genetic etiology, a large deletion of the maternal 15q11.2-13q locus including the UBE3A gene, to create AS model mice. We used the CRISPR/Cas9 technique to delete a 76,225 bp long region spanning the entire UBE3A gene, encompassing both the coding and non-coding elements of the gene, in mice from a C57BL/6N background6. We then bred the animals to obtain UBE3A+/&#8722; heterozygous mice. For face validation of the model, we used animals from crosses of UBE3A+/&#8722; females and wild-type males to gain UBE3A+/- progeny (strain named C57BL/6NCrl-UBE3A&#60;em1(IMPC)Ccpcz&#62;/Ph and later assigned as UBE3AmGenedel/+) and control littermates. We tested their fine and gross motor skills, emotionality, and affect to recapitulate core AS symptoms. In a previous article, we also evaluated the animals&#39; cognitive functions, as AS patients also suffer from intellectual disability6. However, we found no cognitive impairments in UBE3AmGenedel/+ mice, perhaps due to the young age of the animals at the time of testing7. Later examination of the older animals, around 18 weeks old, revealed a deficit in behavioral flexibility during reversal learning in the place preference paradigm. However, the complexity of the employed equipment for this analysis requires a separate methodological module and it is not included here.
The behavioral tests presented here belong to the common phenotyping tools in genetic research, thanks to their high predictive value and sufficient construct validity8,9,10. We used these tests to validate a mouse model of AS by recapitulating core symptoms of the human disease in a reproducible, age-independent manner. The emotionality of the animal was evaluated in the elevated plus maze and open field tests. Both of these tests are based on the approach-avoidance conflict, where animals explore a new environment in search of food, shelter, or mating opportunities while simultaneously avoiding anxiogenic compartments11. Additionally, the open field test is used to test a mouse&#39;s locomotor activity8. The tail suspension test is widely used in depression research to screen for new antidepressant drugs or depressive-like phenotypes in mouse knockout models12. This test evaluates the despair that animals develop over time in an inescapable situation. Motor learning and detailed gait characteristics were determined on the rotarod and in DigiGait, respectively. Animal endurance on the accelerating rod characterizes its balance and movement coordination skills, while detailed analysis of a mouse&#39;s step patterns is a sensitive evaluation of neuromuscular impairments connected to many neurogenerative movement disorders13,14,15. The nestlet shredding test is part of the standard methodology for detecting impulsive behavior in rodents, and since it utilizes natural rodent building behavior, it indicates the animal&#39;s well-being16,17.
The size of the experimental groups was a result of a compromise to meet the 3R rule demands and efficient usage of colony breeding performance. However, to obtain statistical power, the groups had no fewer than 10 individuals, due to the establishment of a sufficient amount of breeding pairs. Unfortunately, breeding performance did not always result in a sufficient number of animals.

Autor im Rampenlicht: Eine Reihe von hochgradig reproduzierbaren Verhaltenstests zur Validierung eines Mausmodells mit Angelman-Syndrom 

Verhaltenscharakterisierung eines Angelman-Syndrom-Mausmodells

Watch this Scientific Journal Video about Elevated Plus Maze Test in an Angelman Syndrome Mouse Model at JoVE.com

Elevated Plus Maze Test in an Angelman Syndrome Mouse Model  

Erhöhter Plus-Plus-Labyrinth-Test in einem Angelman-Syndrom-Mausmodell

Platzieren Sie zunächst das Plus-förmige Labyrinth auf der Testplattform direkt unter der Kamera. Stellen Sie mit dem Potentiometer an der Wand die Lichtintensität mit Hilfe eines Luxometers auf 70 Luxe in der Mitte des Labyrinths ein, wobei der Sensor während der Einstellung in der Mitte des Labyrinths platziert ist. Öffnen Sie die Software mit einem Doppelklick auf das Symbol der Viewer-Software und laden Sie die Konfiguration für Elevated Plus Maze- oder EPM-Tests, indem Sie auf das Symbol oben links auf der Registerkarte "Konfiguration" klicken.Geben Sie die Tierinformationen in die entsprechenden Felder der Registerkarte "Experiment" ein, einschließlich Tier-ID, Genotyp, Geschlecht und Versuchsinformationen. Vergewissern Sie sich, dass die Position der Zone, die offenen Arme und die geschlossenen Arme korrekt konfiguriert sind. Stellen Sie mit einem visuellen Steuerelement und einer Computermaus sicher, dass die virtuellen Gliederungszonen mit den entsprechenden EPM-Zonen übereinstimmen.Platzieren Sie den Mauszeiger auf dem Pfeilsymbol oben links auf der Registerkarte "Erfassung". Nehmen Sie das Tier aus dem häuslichen Käfig und legen Sie es vorsichtig in die Mitte des EPM. Starten Sie das Experiment mit einem Linksklick auf die Computermaus.Speichern Sie die aufgezeichneten Daten nach fünf Minuten, indem Sie auf OK klicken. Benennen Sie die Datei und klicken Sie auf Speichern. Exportieren Sie die Ergebnisse in eine CSV-Datei für die Offline-Analyse, indem Sie auf das Symbol im linken vertikalen Bereich der Registerkarte "Datenanalyse" klicken.Im EPM-Test war keiner der Parameter, die sich auf angstähnliches Verhalten beziehen, in mütterlichen heterozygoten Ube3A-Mutanten verändert.

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Behavior

Elevated Plus Maze Test in an Angelman Syndrome Mouse Model

455 Aufrufe. Platzieren Sie zunächst das Plus-förmige Labyrinth auf der Testplattform direkt unter der Kamera. Stellen Sie mit dem Potentiometer an der Wand die Lichtintensität mit Hilfe eines Luxometers auf 70 Luxe in der Mitte des Labyrinths ein, wobei der Sensor während der Einstellung in der Mitte des Labyrinths platziert ist. Öffnen Sie die Software mit einem Doppelklick auf das Symbol der Viewer-Software und laden Sie die Konfiguration für Elevated Plus Maze- oder EPM-Tests, indem Sie auf das ...

Serie: Elevated Plus Maze Test in an Angelman Syndrome Mouse Model  

Behavioral Characterization of an Angelman Syndrome Mouse Model

This manuscript describes a battery of behavioral tests available to characterize Angelman syndrome (AS)-like phenotypes in an established murine model of AS. We use the rotarod learning paradigm, detailed gait analysis, and nest building test to detect and characterize animal motor impairments. We test animal emotionality in the open field and elevated plus maze tests, as well as the affect in the tail suspension test. When AS mice are tested in the open field test, the results should be interpreted with care, since motor dysfunctions influence mouse behavior in the maze and alter activity scores.
The reproducibility and effectiveness of the presented behavioral tests has already been validated in several independent Uba3a mouse lines with different knockout variants, establishing this set of tests as an excellent validation tool in AS research. Models with the relevant construct and face validity will warrant further investigations to elucidate the pathophysiology of the disease and grant the development of causal treatments.

This manuscript presents a set of highly reproducible behavioral tests to validate an Angelman syndrome mouse model.

This manuscript describes a battery of behavioral tests available to characterize Angelman syndrome (AS)-like phenotypes in an established murine model of ...