Abnormal organization during neurodevelopment in a mouse model of Sandhoff disease

• Published in: Neuroscience research 2020-06, Vol.155, p.12-19
• Main Authors: Ogawa, Yasuhiro, Sasanuma, Yayoi, Shitara, Shuhei, Koshizuka, Asuna, Okada, Rieko, Sakuraba, Hitoshi, Oishi, Kazuhiko
• Format: Article
• Language: English
• Subjects: Animals; Cell Differentiation - physiology; Cerebral cortex; G(M2) Ganglioside - metabolism; Ganglioside; Hexosaminidase B - metabolism; Induced Pluripotent Stem Cells; Lysosomes - metabolism; Mice, Knockout; Neural stem cells; Neural Stem Cells - metabolism; Neurodevelopment; Neurogenesis - physiology; Neurons - metabolism; Sandhoff disease; Sandhoff Disease - genetics; Sandhoff Disease - metabolism
• ISSN: 0168-0102; 1872-8111
• DOI: 10.1016/j.neures.2019.07.004

•Defect of Hexb leads to change in sox2 gene in embryonic cortices.•Defect of Hexb leads to reduced neuronal precursor migration in embryonic cortices.•The production of layer-specific neurons is delayed in cortices of hexb−/− mice. Sandhoff disease (SD) is a genetic disorder caused by a mutation of HEXB, which is the β-subunit gene of β-hexosaminidase A and B (HexA and HexB) in humans. HEXB mutation reduces HexA and HexB enzymatic activities, and results in the massive accumulation of ganglioside GM2 in the nervous system. Severe phenotypes of SD show progressive neurodegeneration in human infants, and lysosomal dysfunction that may affect the early development of the nervous system. In a previous study, neural stem cells (NSCs) and induced pluripotent stem cells derived from SD model mice, which are Hexb-deficient (Hexb−/−), demonstrated impaired neuronal differentiation. This study investigated early neurodevelopment in vivo using Hexb−/− mice. The structure of adult cerebral cortices of Hexb−/− mice was normal. However, the expression of Sox2, an NSC-related gene, was reduced in the embryonic cerebral cortices of Hexb−/− mice. Moreover, a reduction of early neuronal migration and differentiation was observed in the embryonic cerebral cortices of Hexb−/− mice. In addition, we showed that the production of layer-specific neurons was delayed in somatosensory cerebral cortices of Hexb−/− mice. These findings suggest that the alterations observed in embryonic Hexb−/− mice may contribute to deficits in neurodevelopment of SD.