Open AccessGenetic screening and functional analysis of CASP 9 mutations in a Chinese cohort with neural tube defects
Author(s) -
Liu XiaoZhen,
Zhang Qin,
Jiang Qian,
Bai BaoLing,
Du XiaoJuan,
Wang Fang,
Wu LiHua,
Lu XiaoLin,
Bao YiHua,
Li HuiLi,
Zhang Ting
Publication year - 2018
Publication title -
cns neuroscience and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 69
eISSN - 1755-5949
pISSN - 1755-5930
DOI - 10.1111/cns.12797
Subject(s) - neural tube , apoptosis , missense mutation , gene , biology , genetics , hek 293 cells , mutation , transfection , microbiology and biotechnology , bioinformatics , embryo
Summary Aim Neural tube defects ( NTD s) are birth defects of the nervous system and are the second most frequent cause of birth defects worldwide. The etiology of NTD s is complicated and involves both genetic and environmental factors. CASP 9 is an initiator caspase in the intrinsic apoptosis pathway, which in Casp9 −/− mice has been shown to result in NTD s because of decreased apoptosis. The aim of this study was to evaluate the potential genetic contribution of the CASP 9 gene in human NTD s. Methods High‐throughput sequencing was performed to screen genetic variants of CASP 9 genes in 355 NTD cases and 225 matched controls. Apoptosis‐relevant assays were performed on transiently transfected E9 neuroepithelial cells or human embryonic kidney 293T cells, to determine the functional characteristics of NTD ‐specific rare variants under complete or low folic acid (FA) status. Results We found significant expression of CASP 9 rare variants in NTD s and identified 4 NTD ‐specific missense variants. Functional assays demonstrated that a p.Y251C variant attenuates apoptosis by reducing CASP 9 protein expression and decreasing activity of the intrinsic apoptosis pathway. From this, we conclude that this variant may represent a loss‐of‐function mutation. A 4‐time recurrent p.R191G variant did not affect intrinsic apoptosis in complete medium, while it completely inhibited apoptosis induced by low FA medium. Conclusion Our findings identify a genetic link for apoptosis in human NTD s and highlight the effect of gene‐environment interactions in a complex disease.