Characterization and Interrelations of One-Carbon Metabolites in Tissues, Erythrocytes, and Plasma in Mice with Dietary Induced Folate Deficiency

Abstract

Studies on one-carbon metabolism for the assessment of folate deficiency have focused on either metabolites of folate metabolism or methionine cycle. To bridge the gap between deficiency markers in these pathways we designed a dietary induced folate deficiency study using male C57BL/6N mice. After weaning (3 weeks) mice were fed a defined control diet (1 week) before being fed a folate deficient diet (n = 6 mice) and the control diet (n = 6 mice) for 12 additional weeks. Thereafter, we determined total homocysteine in plasma and folate in erythrocytes as well as S-adenosylmethionine, S-adenosylhomocysteine, and six folate vitamers in tissues including 5-methyltetrahydrofolate, 5-formyltetrahydrofolate, 5,10-methenyltetrahydrofolate, tetrahydrofolate, 10-formylfolic acid, and folic acid by means of stable isotope dilution assays coupled with liquid chromatography tandem mass spectrometry. In all organs, except heart (mainly 5-mehtyltetrahydrofolate), tetrahydrofolate constitutes the main vitamer. Moreover, in liver tetrahydrofolate was most abundant followed by 5-methyltetrahydrofolate (heart: tetrahydrofolate), 5-formyltetrahydrofolate, and 5,10-methenyltetrahydrofolate. Because of the significant decrease (p < 0.05) of folate status and S-adenosylmethionine/S-adenosylhomocysteine ratio accompanied with increasing S-adenosylhomocysteine (p < 0.05), hepatocytes are most susceptible to folate deficiency. To the best of our knowledge, we herein present the first method for simultaneous quantitation of eight metabolites for both folate and methionine cycle in one tissue sample, tHcy in plasma, and erythrocyte folate to shed light on physiological interrelations of one-carbon metabolism.

Metabolic Phenotype of Wild-Type and As3mt -Knockout C57BL/6J Mice Exposed to Inorganic Arsenic: The Role of Dietary Fat and Folate Intake

“…The standard rodent chow contains 2mg/kg folic acid, whereas as low as 0.5mg folate/kg is estimated to be sufficient for adult mice (NRC 1995). Notably, some studies used diets with folate content as low as 0.06mg/kg without major effects on animal growth (Kopp et al. 2017).…”

Methylenetetrahydrofolate reductase tagging polymorphisms are associated with risk of non-small cell lung cancer in eastern Chinese Han population

“…Folic acid, or 5-methyltetrahydrofolate, is a cofactor in the metabolism of homocysteine to methionine [ 2 ]. 5,10-ethylenetetrahydrofolate reductase (MTHFR) catalyzed reduction of 5,10-methylenetetrahydrofolate (methylene-THF), a donor of methyl for dUMP to dTMP transform, to methyl-THF, the primary methyl donor in methionine synthesis.…”

The Effect of Dietary Folic Acid Supplementation on Female Germ Cell Aneuploidy

“…Among the colchicine-treated females, plasma and RBC folate were reflective of FA intake. Plasma folate is a sensitive indictor of recent folate intake (Matejcic et al, 2017 (Kopp et al, 2017). We report that among the FA diet groups, females fed a FA deficient diet had significantly higher plasma HCY concentrations, as would be expected.…”

“…plasma HCY is a biomarker for functional folate status, as it indicates the ability of cells to remethylate homocysteine to form methionine (Kopp et al, 2017). Plasma HCY was analyzed using the Advia Centaur XP immunoassay (Siemens Canada), as described by the manufacturer.…”