PSVI-29 Increased N6-methyladenosine in LBW placentas from sows with high backfat thickness is negatively associated with FTO.

Abstract

Maternal obesity is associated with low birth weight (LBW), especially in the domestic animals, such as pigs. However, the underlying mechanism how the LBW occurs in the obese pregnancy has not been well clarified.This study was to determine the role of N6-methyladenosine (m6A) modifications in LBW placenta in maternal obesity.1090 multiparous sows were divided into three groups (Low group: backfat thickness ≤17mm, Medium group: backfat thickness 18-20mm, High group: backfat thickness ≥21mm) to analyze the percentage of LBW piglets. 56, 38, and 56 placentas were collected from sows of each group respectively for the further research. Compared with the other two groups, the sows with high backfat thickness increased the percentage of piglets with birth weight ≤0.9kg and ≤1.0kg significantly. In LBW placentas from a high group, the expression of key genes related to placental angiogenesis, PPARγ and VEGFA showed a remarkable decrease, as well as lower vascularity density. Intriguingly, we for the first time reported that m6A modification was significantly increased in LBW placentas from a high group.The expressions of the demethylase, FTO were decreased at mRNA level as well as the protein level. The specific m6A methylations modified in the PPARγ and VEGFA were enhanced in LBW placentas from the high group. We deduce that the m6A modifications modulated by FTO in the key genes may regulate the placental development, resulting in the LBW.