Ascorbic acid during the suckling period is required for proper DNA demethylation in the liver

Kenichi Kawahori,Fumiko Wada,Yuki Kawasaki,Nozomi Hanzawa,Akihito Ishigami,Yoshihiro Ogawa,Tetsuya Yamada,Koshi Hashimoto,Yoshitaka Kondo,Takashi Kohda,Xunmei Yuan,Kazutaka Tsujimoto

doi:10.1038/s41598-020-77962-7

Abstract

Ascorbic acid (AA, vitamin C) serves as a cofactor for ten-eleven translocation (TET) enzymes and induces DNA demethylation in vitro. However, its role in DNA demethylation in vivo remains unclear. We previously reported that DNA demethylation in the mouse liver was enhanced during the suckling period. Therefore, we hypothesized that DNA demethylation is enhanced in an AA-dependent manner during the suckling period. To examine our hypothesis, we employed wild-type (WT) mice, which synthesize AA, and senescence marker protein-30/gluconolactonase (SMP30/GNL) knockout (KO) mice, which cannot synthesize AA, and analyzed the DNA methylation status in the livers of offspring in both the suckling period and adulthood. SMP30/GNL KO offspring showed DNA hypermethylation in the liver possibly due to low plasma and hepatic AA levels during the suckling period despite the administration of rescue-dose AA to dams. Furthermore, DNA hypermethylation of the fibroblast growth factor 21 gene (Fgf21), a PPARα target gene, persisted into adulthood. In contrast, a high-dose AA administration to SMP30/GNL KO dams during the lactation period restored DNA demethylation in the livers of offspring. Even though a slight increase was observed in plasma AA levels with the administration of rescue-dose AA to WT dams during the gestation and lactation periods, DNA demethylation in the livers of offspring was minimally enhanced. The present results demonstrate that AA intake during the suckling period is required for proper DNA demethylation in the liver.

Highlights

Ten-eleven translocation (TET) enzymes catalyze the oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC)[1,2,3]
We demonstrated that the DNA methylation status of Fgf[21], a PPARα target gene, in early life was maintained in later life
We previously reported that Senescence marker protein-30 (SMP30)/GNL KO offspring were born and matured normally using free access to water containing 1.5 g/L AA, defined as a rescue dose to avoid the effects of an AA d eficiency[20], for dams and o ffspring[14]

Summary

Introduction

Ten-eleven translocation (TET) enzymes catalyze the oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC)[1,2,3]. Recent studies on humans suggested that plasma AA concentrations are related to aberrant DNA methylation in genomic DNA derived from peripheral leukocytes in patients with some cancers[9,10] It currently remains unclear whether AA affects DNA methylation patterns in vivo. We previously reported that SMP30 served as a gluconolactonase (GNL), which catalyzed the penultimate step of Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113‐8510, Japan. We demonstrated that the DNA methylation status of Fgf[21], a PPARα target gene, in early life was maintained in later life

Methods

Results

Conclusion