Effects of a high-fat maternal diet and embryonic Cited2 genotype on gene expression and development in mouse

Deficiency of the transcription factor Cited2 in mice results in cardiac malformation, adrenal agenesis, neural tube, placental defects, and partially penetrant left-right patterning defects resulting from an abnormal Nodal->Pitx2c pathway. Here we show that a maternal high-fat diet more than doubles the penetrance of laterality defects and, surprisingly, induces palatal clefting in Cited2 deficient embryos. Both maternal diet and Cited2 deletion reduce embryo weight and kidney and thymus volume. Expression profiling identified 40 embryonic transcripts including Pitx2 that were significantly affected by embryonic genotype-maternal diet interaction. We show that a high-fat diet reduces Pitx2c levels >2 fold in Cited2 deficient embryos and that Pitx2c deficiency results in cleft palate. Taken together, these results define a novel interaction between maternal high-fat diet and embryonic Cited2 deficiency that affects Pitx2c expression and results in abnormal laterality and cleft palate. Two-factor design: diet (high fat or control) and genotype (Cited2 knockout or wildtype) with n=3 for each of the 4 factor combinations小鼠中转录因子Cited2的缺失会引发心脏畸形、肾上腺发育不全、神经管及胎盘发育缺陷，以及由异常Nodal→Pitx2c信号通路导致的外显率不完全的左右模式发育缺陷。本研究证实，母体高脂饮食可使左右模式缺陷的外显率提升一倍以上，且意外地会在Cited2缺失胚胎中诱导腭裂形成。母体饮食与Cited2基因缺失均会降低胚胎体重以及肾脏与胸腺的体积。表达谱分析共筛选出40种胚胎转录本（包括Pitx2），其表达水平显著受胚胎基因型-母体饮食互作的影响。我们发现，高脂饮食可使Cited2缺失胚胎中的Pitx2c表达水平下调2倍以上，且Pitx2c缺失会引发腭裂。综上，本研究明确了母体高脂饮食与胚胎Cited2缺失之间的新型互作关系——该互作会影响Pitx2c的表达，并最终导致异常左右模式发育与腭裂。本实验采用双因素设计：饮食（高脂或对照）与基因型（Cited2敲除型或野生型），4种因子组合每组的样本量均为n=3。