Maternal Electronic Cigarette Exposure Induces Dysregulation of Autophagy via Oxidative Stress/DNA Methylation in Pulmonary Hypertension Offspring

Objective: Electronic cigarettes (ECs) differ from traditional tobacco smoke but may contribute to cardiopulmonary remodeling. Pulmonary hypertension (PH), characterized by pulmonary artery and right ventricle remodeling, poses a significant risk of mortality in infants, children, and adolescents. However, the impact of maternal EC exposure on PH development in offspring remains unclear. To address this, we established a PH rat model with maternal EC exposure.

Methods: Maternal EC exposure was initiated on gestation day 12 via electronic nicotine delivery systems. Offspring were administered monocrotaline (MCT) at 6 weeks of age (6-wo) to induce PH. Mechanistic experiments were conducted at 10-week-old (10-wo). Protein expression of NADPH oxidases, DNA methyltransferases, and autophagy-related markers was analyzed by Western blot. Morphological changes and the severity of PH were evaluated via hematoxylin and eosin (HE) staining and echocardiography, respectively. Furthermore, the involvement of the oxidative stress/DNA methylation/autophagy axis in response to maternal EC exposure was confirmed through a combination of ELISA, Western blot, HE staining, and echocardiography. Additionally, ATG5 mRNA expression was measured by qRT-PCR.

Results: Compared with control conditions, maternal EC exposure significantly worsened MCT-induced PH in male offspring. This was associated with increased oxidative stress, DNA hypomethylation, and anomalous autophagy in the offspring. In vivo treatment with chloroquine inhibited autophagy and ameliorated PH development in offspring exposed to maternal EC. Furthermore, N-acetylcysteine (NAC), an antioxidant, attenuated maternal EC exposure-induced oxidative stress, DNA hypomethylation, and excessive autophagy, thereby improving PH. DNA hypermethylation also reversed PH development, accompanied by reduced oxidative stress and suppressed autophagy. ATG5, a key regulator of autophagy, was identified as a potential therapeutic target, as its repression mitigated PH in maternal EC-exposed offspring.

Conclusion: Maternal EC exposure induces oxidative stress and DNA hypomethylation in offspring, leading to anomalous autophagy and exacerbation of PH development. Targeting ATG5-mediated autophagy may represent a novel therapeutic approach for improving PH outcomes in offspring exposed to maternal EC.