Topical Area: Nutrient-Gene Interactions
Objectives : Till date there have been studies to check the individual effect of maternal folate and vitamin B12 during pregnancy but less is known regarding the combined effect of both vitamins on growth and neuro-behaviour of the off-springs. So, the present study was designed with an aim to check the combined effect of both vitamins on: Neurobehaviour development of off-springs and epigenetic regulation of imprinted (H19, IGF2, IGF2R) genes.
Methods : Four week old C57BL/6 female mice were randomized into nine groups BNFN, BNFO, BNFD, BDFN, BDFD, BDFO, BOFN, BOFO, BOFD and were fed diet for six weeks while male mice were on normal diet. Mating was performed and pregnant dams gave birth to the F1 off-springs. Both male and female fetuses in F1 generation were fed diets as per the dietary groups of their mothers. After six weeks males were used for neurobehavior studies and mating was carried out, on day 20 of gestation maternal and fetal tissues (F2 generation) were isolated. Folate, homocysteine and B12 levels were analyzed along with mRNA expression, promoter DNA methylation and histone modification of imprinted genes.
Results : Folate, vitamin B12 and homocysteine levels were altered in different folate and B12 dietary groups (P< 0.01). Adult mice exposed to folate and vitamin B12 conditions expressed delayed locomoter functions in BDFD (25.74%), BNFD (20.75%) and BOFD (20.16%) groups, impaired spatial learning and memory ability and increased GSH/GSSG levels in brain under deficient conditions.In maternal and fetal tissues, H19 was found to be over-expressed under deficient conditions which was co-related with decreased promoter methylation and decrease suppressive histone methylation marks H3K9me3 and H3K27me3 (P< 0.01) and increase in H3K4me2. Genomic imprinting patterns were found to be reversed in H19 in both male and female fetuses. IGF2 along with IGF2R showed loss of expression with increased methylation in promoter region (P< 0.05) and suppressive histone methylation marks in deficient conditions.
Abbreviations: BN: B12 Normal FN: Folate Normal FD: Folate deficient FO: Folate over supplementation BD: B12 deficient BO: B12 over supplementation
Conclusions : Maternal dietary ratio of folate and B12 during pregnancy influence neurobehaviour development and alters the establishment of proper imprints during development.
Funding Sources : Department of Biotechnology