Abstract
Folates act as co-factors for transfer of one-carbon units for nucleotide production, methylation and other biosynthetic reactions. Comprehensive profiling of multiple folates can be achieved using liquid chromatography tandem mass spectrometry, enabling determination of their relative abundance that may provide an indication of metabolic differences between cell types. For example, cell lines exposed to methotrexate showed a dose-dependent elevation of dihydrofolate, consistent with inhibition of dihydrofolate reductase. We analysed the folate profile of E. coli sub-types as well as cell lines and embryonic tissue from both human and mouse. The folate profile of bacteria differed markedly from those of all the mammalian samples, most notably in the greater abundance of formyl tetrahydrofolate. The overall profiles of mouse and human fibroblasts and mid-gestation mouse embryos were broadly similar, with specific differences. The major folate species in these cell types was 5-methyl tetrahydrofolate, in contrast to lymphoblastoid cell lines in which the predominant form was tetrahydrofolate. Analysis of embryonic human brain revealed a shift in folate profile with increasing developmental stage, with a decline in relative abundance of dihydrofolate and increase in 5-methyl tetrahydrofolate. These cell type-specific and developmental changes in folate profile may indicate differential requirements for the various outputs of folate metabolism.Electronic supplementary materialThe online version of this article (doi:10.1007/s11010-013-1613-y) contains supplementary material, which is available to authorized users.
Highlights
Folate one-carbon metabolism (FOCM) comprises a network of interlinked reactions in which folates act as cofactors for transfer of one-carbon units required in various biosynthetic reactions (Fig. 1) [1,2,3]
The abundance of individual folates is expressed as a proportion of the total folate content in a bacteria, b human lymphoblastoid and primary fibroblast cell lines, and c primary mouse embryonic fibroblasts and mid-gestation (E12.5) embryos. a The relative abundance of all major folates differed between bacterial sub-types (*significantly different from corresponding folate in type B, p \ 0.001). b Amongst human cell lines, there was a significant difference in the proportion of THF, 5,10-methylene THF and 5-methyl THF (**p \ 0.001; *p \ 0.02 difference in proportion compared with the corresponding folate in lymphocytes)
The overall folate profile appeared similar between mouse embryos and fibroblasts but we observed significant differences in the proportion of THF, 5,10-methylene THF and 5-methyl THF (**p \ 0.001; *p \ 0.02 difference in proportion compared with the corresponding folate in embryos)
Summary
Folate one-carbon metabolism (FOCM) comprises a network of interlinked reactions in which folates act as cofactors for transfer of one-carbon units required in various biosynthetic reactions (Fig. 1) [1,2,3]. Cellular uptake is mediated by folate receptors (FOLR1 and FOLR2) and the reduced folate carrier (RFC; SLC19a1) and in the gut by the proton-coupled folate transporter (PCFT; SLC46A1)[4]. Embryonic lethality of mice lacking Folr or Rfc demonstrates the necessity of folate uptake for postimplantation development [5,6,7]. Abnormalities in FOCM have been implicated in a variety of pathological conditions including cancer, neural tube defects (NTDs), cardiovascular disease, anaemia and neurological conditions [3, 8,9,10,11]. FOCM is implicated in diseases that may occur throughout life, Mol Cell Biochem (2013) 378:229–236
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
