427 - Perinatal Nicotine Exposure Alters Expression of Differentially Methylated Spermatozoal Genes on Multiple Organs Across Generation

Poster Number: 427
Publication Number: 427.429

Leela Afrose, The Lundqusit Institute, Torrance, CA, United States; Tracy T. Dao, Lundquist Institute, Garden Grove, CA, United States; Jie Liu, Lundquist Institute at Harbor-UCLA Medical Center, Torrance, CA, United States; Celia Yu, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States; Ying Wang, The Lundquist Institute, Torrance, CA, United States; Dylan Hatai, The Lundquist Institute at UCLA-Harbor Medical Center, Torrance, CA, United States; Virender K. Rehan, Harbor-UCLA Medical Center, Torrance, CA, United States

Background: We recently demonstrated that perinatally nicotine exposed rats have differential DNA methylation in the proximity of nicotine-response genes in their sperms. Gene ontology and pathway enrichment analysis suggested a possible link of the spermatozoal differential DNA methylation with the F1 offspring asthma phenotype. However, the underlying mechanisms remain unknown. We hypothesized that, spermatogonial changes detected in F0 nicotine exposed animal sperm cells could possibly explain the transmission of perinatal nicotine induced phenotypes on other organs and across generations.

Objective: In order to determine the wider potential intergenerational impact of nicotine‐induced differential methylation changes in sperm cells of F0 generation exposed offspring, we investigated the expression pattern of these genes in the lung and brain tissues of F2 generation offspring.

Design/Methods: Sprague Dawley rat dams (F0) received nicotine (1 mg/kg, sc) or saline from embryonic day 6 (E6) until postnatal day 21 (PND21). Pups (F1) were weaned at PND21 and used as breeders to generate F2 without any subsequent exposure to nicotine in the F1 progeny. F2 pups were weaned at PND21. At PND60, F2 males (n=20; 10 control, 10 nicotine) were sacrificed, and their lungs and brains were collected and flash-frozen for performing qRT-PCR for 4 differentially methylated genes [AABR07051515.1 (a lincRNA, known to modulate lung function,), Dio1 (iodothyronine deiodinase 1, catalyzes thyroid hormone T3), NMU (Neuromedin U), and Sec14l5 (helps in lipid metabolism)] in sperm cells of the F0 nicotine exposed males.

Results: The expression of the top 2 differentially hypermethylated genes AABR07051515.1, and Dio1, in the nicotine exposed F1 sperm cells were upregulated and downregulated, respectively (p ≤ 0.05), in F2 lungs and brains. In addition, similar to the F1 progeny, NMU gene expression was downregulated (p ≤ 0.05) in F2 lungs and brain. Interestingly, Sec14l5 gene’s expression was downregulated in the lung and upregulated in the brain for F2 progeny of the nicotine exposed group. Conclusion(s): Our data further support the concept that perinatal nicotine exposure-induced spermatozoal epigenetic reprogramming, specifically DNA methylation, alters the nicotine response genes in the brain and the lung, which likely drives the intergenerational transmission of perinatal nicotine-induced phenotypes in these organs.
NIH (HL151769, HD127237, HD071731, and HL152915) and TRDRP (23RT-0018; 27IP- 0050; and T29IR0737).