Body Mass Index in Pregnancy Does Not Affect Peroxisome Proliferator-activated Receptor Gamma Promoter Region (-359 to -260) Methylation in the Neonate

Abstract

Background: Obesity in pregnancy can contribute to epigenetic changes. Aim: To assess whether body mass index (BMI) in pregnancy is associated with changes in the methylation of the peroxisome proliferator‑activated receptor γ (PPAR) promoter region (−359 to − 260) in maternal and neonatal leukocytes. Subjects and Methods: In this matched, cohort study 41 pregnant women were allocated into two groups: (a) Normal weight (n = 21) and (b) overweight (n = 20). DNA was extracted from maternal and neonatal leukocytes (4000–10,000 cells) in MagNA Pure (Roche) using MagNA Pure LC DNA Isolation Kit 1 (Roche, Germany). Treatment of DNA (2 μg) was performed with sodium bisulfite (EZ DNA Methylation‑Direct™ Kit; Zymo Research). Real‑time quantitative polymerase chain reaction (qPCR) was performed in a LightCycler 2.0 (Roche) using the SYBR® Advantage® qPCR Premix Kit (Clontech). The primers used for PPARg coactivator (PPARG) M3 were 5’‑aagacggtttggtcgatc‑3’ (forward), and5’‑cgaaaaaaaatccgaaatttaa‑3’ (reverse) and those for PPARG unmethylated were: 5’‑gggaagatggtttggttgatt‑3’ (forward) and 5’‑ttccaaaaaaaaatccaaaatttaa‑3’ (reverse). Intergroup differences were calculated using the Mann–Whitney U‑test, and intragroup differences, with the Wilcoxon test (IBM SPSS Statistics for Windows, Version 19.0. Armonk, NY: IBM Corp.). Results: Significant differences were found in BMI, pregestational weight, and postdelivery weight between groups but not in the methylation status of the PPARγ promoter region (−359 to − 260). Conclusion: The PPARγ promoter region (−359 to − 260) in peripheral leukocytes is unlikely to get an obesity‑induced methylation in pregnancy.