N⁶-methyladenosine (M⁶A) in fetal offspring modifies mitochondrial gene expression following gestational nano-TiO₂ inhalation exposure

N⁶-methyladenosine (m⁶A) is the most prominent epitranscriptomic modification to RNA in eukaryotes, but it’s role in adaptive changes within the gestational environment are poorly understood. We propose that gestational exposure to nano titanium dioxide (TiO₂) contributes to cardiac m⁶A methylation in fetal offspring and influences mitochondrial gene expression. 10-week-old pregnant female FVB/NJ wild-type mice underwent 6 nonconsecutive days of whole-body inhalation exposure beginning on gestational day (GD) 5. Mice were exposed to filtered room air or nano-TiO₂ with a target aerosol mass concentration of 12 mg/m³. At GD 15 mice were humanely killed and cardiac RNA and mitochondrial proteins extracted. Immunoprecipitation with m⁶A antibodies was performed followed by sequencing of immunoprecipitant (m⁶A) and input (mRNA) on the Illumina NextSeq 2000. Protein extraction, preparation, and LC-MS/MS were used for mitochondrial protein quantification. There were no differences in maternal or fetal pup weights, number of pups, or pup heart weights between exposure and control groups. Transcriptomic sequencing revealed 3648 differentially expressed mRNA in nano-TiO₂ exposed mice (<i>Padj</i> ≤ 0.05). Transcripts involved in mitochondrial bioenergetics were significantly downregulated (83 of 85 genes). 921 transcripts revealed significant m⁶A methylation sites (<i>Padj</i> ≤ 0.10). 311 of the 921 mRNA were identified to have both 1) significantly altered expression and 2) differentially methylated sites. Mitochondrial proteomics revealed decreased expression of ATP Synthase subunits in the exposed group (<i>P</i> ≤ 0.05). The lack of m⁶A modifications to mitochondrial transcripts suggests a mechanism for decreased transcript stability and reduced protein expression due to gestational nano-TiO₂ inhalation exposure.N⁶-甲基腺苷（N⁶-methyladenosine, m⁶A）是真核生物中最常见的RNA表观转录组修饰，但其在妊娠环境适应性变化中的作用仍知之甚少。本研究提出，妊娠期暴露于纳米二氧化钛（nano titanium dioxide, TiO₂）可导致胎儿后代心脏发生m⁶A甲基化，并影响线粒体基因表达。研究选取10周龄的妊娠雌性FVB/NJ野生型小鼠，于妊娠第5天（GD 5）起进行为期6天的非连续性全身吸入暴露：暴露组小鼠接触目标气溶胶质量浓度为12 mg/m³的纳米TiO₂气溶胶，对照组小鼠接触过滤后的室内空气。于妊娠第15天（GD 15）对小鼠实施人道处死，提取心脏组织RNA与线粒体蛋白。采用m⁶A抗体进行免疫沉淀实验，随后借助Illumina NextSeq 2000测序平台对免疫沉淀物（m⁶A富集样本）及输入对照样本（总mRNA）进行测序；线粒体蛋白定量则通过蛋白提取、样品制备及液相色谱-串联质谱（LC-MS/MS）完成。实验结果显示，暴露组与对照组的母鼠体重、胎鼠数量、胎鼠体重及胎鼠心脏重量均无显著差异。转录组测序结果表明，纳米TiO₂暴露组小鼠存在3648个差异表达mRNA（校正后P值Padj ≤ 0.05），其中参与线粒体生物能量代谢的转录本显著下调，85个相关基因中有83个表达量降低。另有921个转录本携带显著差异的m⁶A甲基化位点（Padj ≤ 0.10）；在这921个mRNA中，311个同时满足两个条件：1）表达水平显著改变，2）存在差异甲基化位点。线粒体蛋白质组学分析显示，暴露组小鼠的ATP合酶亚基表达量显著降低（P ≤ 0.05）。线粒体转录本未发生m⁶A修饰这一现象，提示妊娠期纳米TiO₂吸入暴露可通过降低转录本稳定性、减少蛋白表达的分子机制发挥影响。

搜集汇总

背景与挑战

背景概述

该数据集研究了孕期纳米二氧化钛（nano-TiO2）吸入暴露对胎儿小鼠心脏的影响，重点关注N6-甲基腺苷（m6A）表观转录组修饰和线粒体基因表达。通过转录组和蛋白质组学分析，发现暴露导致mRNA表达差异和m6A甲基化变化，并关联到线粒体生物能量学相关基因下调及ATP合酶亚基表达减少。数据集提供了原始测序和蛋白质定量数据，用于探索环境暴露如何通过表观遗传机制影响胎儿心脏发育。