Prenatal exposure to environmental toxins induces sexually dimorphic transcriptome changes in neonatal offspring

Purpose: Gestational exposure to environmental toxins and socioeconomic stressors are epidemiologically linked to neurodevelopmental disorders with strong male-bias, such as autism. We modeled these prenatal risk factors in mice, by co-exposing pregnant dams to an environmental pollutant and limited-resource stress, which robustly activated the maternal immune system. Only male offspring displayed long-lasting behavioral abnormalities and alterations in the activity of brain networks encoding social interactions. Cellularly, prenatal stressors diminished microglial function within the anterior cingulate cortex, a central node of the social coding network, in males during early postnatal development. Genetic ablation of microglia during the same critical period mimicked the impact of prenatal stressors on a male-specific behavior, indicating that environmental stressors alter neural circuit formation in males via impairing microglia function during development. Overall design: Methods: Pregnant dams were exposed with either CON or DEP+MS, at P8 prefrontal cortices of male and female offspring born to exposed mothers were collected and RNA was extracted. . RNA-seq libraries were prepared using the commercially available KAPA Stranded mRNA-Seq Kit. Sequencing was performed on an Illumina NovaSeq 6000 using S-Prime flow cell at 50bp paired-end

研究目的：妊娠期暴露于环境毒素与社会经济压力源，在流行病学层面与具有显著雄性偏向性的神经发育障碍（如自闭症）存在明确关联。本研究在小鼠模型中复现上述产前风险因素：对孕鼠联合施加环境污染物暴露与资源限制应激，该处理可显著激活母体免疫系统。仅雄性子代呈现出持续性行为异常，以及编码社交互动的脑网络活动发生改变。在细胞层面，产前应激可在雄性子代出生后早期发育阶段，削弱其前扣带回皮层——社交编码网络的核心节点——内的小胶质细胞（microglia）功能。在同一关键时期对小胶质细胞进行基因消融，可模拟产前应激对雄性特异性行为的影响，提示环境应激可通过损害发育阶段的小胶质细胞功能，改变雄性个体的神经环路形成。整体实验设计与方法：将孕鼠分为对照组（CON）与实验组（DEP+MS）进行暴露处理；在子代出生后第8天（P8），采集暴露母鼠所产雄性与雌性子代的前额叶皮层并提取RNA。采用商业化KAPA Stranded mRNA-Seq试剂盒构建转录组测序（RNA-seq）文库，随后在Illumina NovaSeq 6000测序平台上，使用S-Prime流动槽开展50bp双端测序。