HumanGNPTABstuttering mutations engineered into mice cause vocalization deficits and astrocyte pathology in the corpus callosum

Abstract

Stuttering is a common neurodevelopmental disorder that has been associated with mutations in genes involved in intracellular trafficking. However, the cellular mechanisms leading to stuttering remain unknown. Engineering a mutation in N-acetylglucosamine-1-phosphate transferase subunits α and β (GNPTAB) found in humans who stutter into the mouse Gnptab gene resulted in deficits in the flow of ultrasonic vocalizations similar to speech deficits of humans who stutter. Here we show that other human stuttering mutations introduced into this mouse gene, Gnptab Ser321Gly and Ala455Ser, produce the same vocalization deficit in 8-day-old pup isolation calls and do not affect other nonvocal behaviors. Immunohistochemistry showed a marked decrease in staining of astrocytes, particularly in the corpus callosum of the Gnptab Ser321Gly homozygote mice compared to wild-type littermates, while the staining of cerebellar Purkinje cells, oligodendrocytes, microglial cells, and dopaminergic neurons was not significantly different. Diffusion tensor imaging also detected deficits in the corpus callosum of the Gnptab Ser321Gly mice. Using a range of cell type-specific Cre-drivers and a Gnptab conditional knockout line, we found that only astrocyte-specific Gnptab-deficient mice displayed a similar vocalization deficit. These data suggest that vocalization defects in mice carrying human stuttering mutations in Gnptab derive from abnormalities in astrocytes, particularly in the corpus callosum, and provide support for hypotheses that focus on deficits in interhemispheric communication in stuttering.

Rapid development of mature vocal patterns of ultrasonic calls in a fast-growing rodent, the yellow steppe lemming (Eolagurus luteus)

“…Ultrasonic vocalizations (USV) of laboratory rodents represent age-dependent indicators of animal emotional arousal [1][2][3][4][5][6] and may serve for modeling human diseases and the evaluation of drugs and medicaments effects [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The overwhelmingly preferred mice USV model [1,8,10,[21][22][23][24] is applicable for USV ontogeny [7,16,19,20,[25][26][27][28][29][30][31][32][33].…”

“…The overwhelmingly preferred mice USV model [1,8,10,[21][22][23][24] is applicable for USV ontogeny [7,16,19,20,[25][26][27][28][29][30][31][32][33]. However, in spite of the numerous wild-type and mutant strains of laboratory mice Mus musculus [18,26,27,[34][35][36][37], the mice model does not suffice for all spectrum of biomedical research based on analyses of USV [3,5,38,39]. For example, the mice model does not provide distinctive vocal correlates of negative and positive emotions [5], which are embedded in rat model of 22 kHz and 50-kHz USV calls [3].…”

Time to re-engage psychiatric drug discovery by strengthening confidence in preclinical psychopharmacology

“…Equally impressive is the discovery of the role played by the GNPTAB gene products, the N-acetylglucosamine-1-phosphate transferase α and β subunits, in the common neurodevelopmental disorder of stuttering (Han et al 2019 ). Unlike the relatively minor effects of copy number variants (CNVs) engineered as significant risk factors for the development of schizophrenia (see below), genetic engineering of the human stuttering mutation into mice resulted in deficits in the flow of ultrasonic vocalisations very similar in pattern to stuttering deficits in humans.…”

Evaluation of recurrent GNPTAB, GNPTG, and NAGPA variants associated with stuttering

“…Additionally, dominance may change according to the level of organization of the phenotype and its variations highlight the complexity of understanding genetic influences on phenotypes 27 . Two other GNPTAB homozygous mutations p.Ser321Gly and p.Ala455Ser engineered in mice, also displayed vocalization deficits traceable to abnormalities in astrocytes of corpus callosum 21 …”