Host: The Japanese Society of Toxicology
Name : The 50th Annual Meeting of the Japanese Society of Toxicology
Date : June 19, 2023 - June 21, 2023
Epigenetic modifications to the DNA strand have been implicated in responses to environmental stimuli as memories without alternation of DNA sequence. In particular, during development and growing stages, organisms tend to retain acquired epigenetic memories for a long period of time, after environmental stimuli have been gone. To address this, we set up two-series of experiments on (1) epigenetic reprograming of histone modifications during medaka early development, and (2) identification of epigenetic memories after early nutritional stimulation in medaka larva and adult. For epigenetic reprograming we analyzed histone modification patterns after fertilization, genome-widely and quantitatively by applying the spike-in ChIP-seq technique. In spite of the extensive erasure of histone modifications, we found retention of some modifications (H3K27ac, H3K27me3 and H3K9me3) during reprogramming, and examined their role in gene expression and development. For epigenetic memories, we chased for long-term changes in the epigenome induced by early transient feeding of high-fat diet (HFD) in the liver. HFD induced drastic changes in the hepatic transcriptome, chromatin accessibility, and histone modifications especially in metabolic genes and that subsequent long-term control-diet feeding returned most of the changes to normal levels. However, a certain number of genomic loci showed persistent epigenetic changes, especially around genes related to cell signaling, implying latent changes in the cellular state of the liver triggered by early-life HFD feeding