Effects of gene-by-environment interaction on the mRNA profile in the light of differential susceptibility

Purpose: Investigation of effects of early adversity in mice deficient for serotonin transporter on mRNA expression in the context of differential susceptibility Methods: Following prenatal stress and behavioural screening in adulthood, month old females, either wildtype or carrying a heterozygous knockout of the serotonin transporter gene, were sacrificed, brains extracted, the hippocampi of both hemispheres dissected, blended and separated in two portions. From one of these portions RNA was extracted. Extracted RNA was further processed by an external company, i.e. IGA Technologies (Udine, Italy). Following library preparation, samples were sequenced on the illumina HiSeq2000 platform (single end, 50 bp, 30 million reads/sample). Reads were mapped to the Mus musculus GRCm38.p5 genome using STAR (Dobin et al. 2013). Following mapping, the reads per position were determined using HTSeq (Anders et al. 2015). These counts were then used for the analysis of differentially expressed genes (DEGs) using the R package DeSeq2 (Love et al. 2014). Results: dependent on the serotonin transporter genotype and behaviourally determined susceptibility to early life adversity, animals displayed distinct gene expression. As expected, the effect sizes and significances were rather subtle. Conclusion: the modulation of differential susceptibility seems to be modulated by distinct mRNA expression profiles, dependent on the serotonin transporter genotype RNA expression affected in serotonin transporter deficient or wildtype offspring of prenatal stress that do or do not succumb to the adverse effects of prenatal stress, i.e. vulnerable or resilient offspring [contributor] IGA Technologies (Undine, Italy)研究目的：探究5-羟色胺转运蛋白（serotonin transporter）缺陷小鼠在早期逆境暴露下，于差异易感性背景中对mRNA表达的影响。 研究方法：通过产前应激造模并在成年后开展行为学筛查后，选取月龄雌性野生型与5-羟色胺转运蛋白基因杂合敲除型小鼠，实施安乐死并剥离脑组织，分离双侧海马体，匀浆后均分为两份。取其中一份提取RNA，交由外部机构IGA Technologies（意大利乌迪内）完成后续RNA处理流程。完成文库构建后，采用Illumina HiSeq2000平台进行测序（单端测序，读长50 bp，每个样本获取3000万条reads）。使用STAR软件（Dobin等，2013）将测序reads比对至小家鼠（Mus musculus）GRCm38.p5参考基因组。比对完成后，借助HTSeq工具（Anders等，2015）统计各基因组位置的reads计数。随后利用R包DeSeq2（Love等，2014）开展差异表达基因（DEGs）分析。 研究结果：根据5-羟色胺转运蛋白基因型与行为学鉴定的早期逆境易感性分组，小鼠呈现出特征性的基因表达模式。正如预期，效应量与统计学显著性均较为微弱。 研究结论：差异易感性的调控似乎由特异性的mRNA表达谱所介导，该表达谱依赖于5-羟色胺转运蛋白基因型；产前应激子代中，无论5-羟色胺转运蛋白缺陷型还是野生型个体，若易受产前应激的不良影响（易感子代）或可耐受该不良影响（耐受子代），其RNA表达均发生改变。 [贡献者] IGA Technologies（意大利乌迪内）