Abstract

Maternal engineered nanomaterial (ENM) exposure during gestation has been associated with negative long-term effects on cardiovascular health in progeny. Here, we evaluate an epitranscriptomic mechanism that contributes to these chronic ramifications and whether overexpression of mitochondrial phospholipid hydroperoxide glutathione peroxidase (mPHGPx) can preserve cardiovascular function and bioenergetics in offspring following gestational nano-titanium dioxide (TiO₂) inhalation exposure. Wild-type (WT) and mPHGPx (Tg) dams were exposed to nano-TiO₂ aerosols with a mass concentration of 12.01 ± 0.50 mg/m³ starting from gestational day (GD) 5 for 360 mins/day for 6 nonconsecutive days over 8 days. Echocardiography was performed in pregnant dams, adult (11-week old) and fetal (GD 14) progeny. Mitochondrial function and global N⁶-methyladenosine (m⁶A) content were assessed in adult progeny. MPHGPx enzymatic function was further evaluated in adult progeny and m⁶A-RNA immunoprecipitation (RIP) was combined with RT-qPCR to evaluate m⁶A content in the 3′-UTR. Following gestational ENM exposure, global longitudinal strain (GLS) was 32% lower in WT adult offspring of WT dams, with preservation in WT offspring of Tg dams. MPHGPx activity was significantly reduced in WT offspring (29%) of WT ENM-exposed dams, but preserved in the progeny of Tg dams. M⁶A-RIP-qPCR for the SEC insertion sequence region of mPHGPx revealed hypermethylation in WT offspring from ENM-exposed WT dams, which was thwarted in the presence of the maternal transgene. Our findings implicate that m⁶A hypermethylation of mPHGPx may be culpable for diminished antioxidant capacity and resultant mitochondrial and cardiac deficits that persist into adulthood following gestational ENM inhalation exposure.

摘要

妊娠期间暴露于母体工程纳米材料 (ENM) 与对后代心血管健康的长期负面影响有关。在这里，我们评估了导致这些慢性后果的表观转录组学机制，以及线粒体磷脂氢过氧化物谷胱甘肽过氧化物酶 (mPHGPx) 的过表达是否可以在妊娠期纳米二氧化钛 (TiO ₂ ) 吸入暴露后保护后代的心血管功能和生物能量。野生型 (WT) 和 mPHGPx (Tg) 大坝暴露于质量浓度为 12.01 ± 0.50 mg/m ^{3的纳米 TiO} _{2气溶胶中}从妊娠日 (GD) 5 开始，每天 360 分钟，连续 6 天，超过 8 天。在怀孕的水坝、成年（11 周龄）和胎儿（GD 14）后代中进行超声心动图检查。在成年后代中评估线粒体功能和整体 N ⁶ -甲基腺苷 (m ⁶ A) 含量。在成年后代中进一步评估 MPHGPx 酶促功能，并将 m ⁶ A-RNA 免疫沉淀 (RIP) 与 RT-qPCR 相结合以评估 m ⁶3'-UTR 中的内容。妊娠期 ENM 暴露后，WT 水坝的 WT 成年后代的整体纵向应变 (GLS) 降低了 32%，而 Tg 水坝的 WT 后代则保持不变。MPHGPx 活性在 WT ENM 暴露水坝的 WT 后代 (29%) 中显着降低，但保留在 Tg 水坝的后代中。用于 mPHGPx 的 SEC 插入序列区域的M ⁶ A-RIP-qPCR 揭示了来自 ENM 暴露 WT 水坝的 WT 后代的高甲基化，这在母体转基因存在下被阻止。我们的研究结果表明，mPHGPx 的m ^{6 A 高甲基化可能是导致抗氧化能力降低以及由此产生的线粒体和心脏缺陷在妊娠期 ENM 吸入暴露后持续到成年期的罪魁祸首。}