Two novel mouse models mimicking minor deletions in 22q11.2 deletion syndrome revealed the contribution of each deleted region to psychiatric disorders

Ryo Saito, Chika Miyoshi, Michinori Koebis, Itaru Kushima, Kazuki Nakao, Daisuke Mori, Norio Ozaki, Hiromasa Funato, Masashi Yanagisawa, Atsu Aiba

Research output: Contribution to journalArticlepeer-review

Abstract

22q11.2 deletion syndrome (22q11.2DS) is a disorder caused by the segmental deletion of human chromosome 22. This chromosomal deletion is known as high genetic risk factors for various psychiatric disorders. The different deletion types are identified in 22q11.2DS patients, including the most common 3.0-Mb deletion, and the less-frequent 1.5-Mb and 1.4-Mb deletions. In previous animal studies of psychiatric disorders associated with 22q11.2DS mainly focused on the 1.5-Mb deletion and model mice mimicking the human 1.5-Mb deletion have been established with diverse genetic backgrounds, which resulted in the contradictory phenotypes. On the other hand, the contribution of the genes in 1.4-Mb region to psychiatric disorders is poorly understood. In this study, we generated two mouse lines that reproduced the 1.4-Mb and 1.5-Mb deletions of 22q11.2DS [Del(1.4 Mb)/+ and Del(1.5 Mb)/+] on the pure C57BL/6N genetic background. These mutant mice were analyzed comprehensively by behavioral tests, such as measurement of locomotor activity, sociability, prepulse inhibition and fear-conditioning memory. Del(1.4 Mb)/+ mice displayed decreased locomotor activity, but no abnormalities were observed in all other behavioral tests. Del(1.5 Mb)/+ mice showed reduction of prepulse inhibition and impairment of contextual- and cued-dependent fear memory, which is consistent with previous reports. Furthermore, apparently intact social recognition in Del(1.4 Mb)/+ and Del(1.5 Mb)/+ mice suggests that the impaired social recognition observed in Del(3.0 Mb)/+ mice mimicking the human 3.0-Mb deletion requires mutations both in 1.4-Mb and 1.5 Mb regions. Our previous study has shown that Del(3.0 Mb)/+ mice presented disturbance of behavioral circadian rhythm. Therefore, we further evaluated sleep/wakefulness cycles in Del(3.0 Mb)/+ mice by electroencephalogram (EEG) and electromyogram (EMG) recording. EEG/EMG analysis revealed the disturbed wakefulness and non-rapid eye moving sleep (NREMS) cycles in Del(3.0 Mb)/+ mice, suggesting that Del(3.0 Mb)/+ mice may be unable to maintain their wakefulness. Together, our mouse models deepen our understanding of genetic contributions to schizophrenic phenotypes related to 22q11.2DS.

Original languageEnglish (US)
Article number68
JournalMolecular brain
Volume14
Issue number1
DOIs
StatePublished - Dec 2021
Externally publishedYes

Keywords

  • 22q11.2 deletion syndrome
  • Behavioral analysis
  • Mouse models
  • Rare deletion types
  • Sleep analysis

ASJC Scopus subject areas

  • Molecular Biology
  • Cellular and Molecular Neuroscience

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