Epigenetic effects of N-3 polyunsaturated fatty acids

Abstract

N-3 polyunsaturated fatty acids (PUFAs) are essential components of the cell membrane. They display a wide range of effects, acting on brain functions and cardiovascular physiology. N-3 long-chain PUFAs have to be ingested from the diet and are nowadays quasi restricted to fish or seafood and are thus consumed in unsatisfactory low proportions compared to n-6 PUFAs. Experimental animal models have shown that n-3 PUFAs could act through epigenetic effects. For instance, maternal n-3 uptakes correlate negatively with offspring body weight in rodents. Such an association has been debated in humans. Yet, there is a negative correlation with n-3 maternal intakes and child's sensitivity to allergies or asthma. In experimental animals or in vitro, n-3 supplementation or incubation can modify DNA methylation state, either globally or locally on some gene promoters. The promoter methylation of fatty acid desaturase-2 (FADS2), a desaturase involved in PUFA synthesis, is increased by DHA. The transcriptome of micro-RNAs (miR) is also modified by n-3 PUFAs. The compounds derived from n-3 PUFAs, such as ResolvinD1, are also able to alter miR synthesis to resolve inflammation. Therefore, these still fragmentary observations open the road to deepen the knowledge of the varied molecular mechanisms of the n-3 PUFAs.