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Maternal choline availability is essential for fetal neurogenesis. Choline deprivation (CD) causes hypomethylation of specific CpG islands in genes controlling cell cycling in fetal hippocampus. We now report that, in C57BL/6 mice, CD during gestational days 12-17 also altered methylation of the histone H3 in E17 fetal hippocampi. In the ventricular and subventricular zones, monomethyl-lysine 9 of H3 (H3K9me1) was decreased by 25% (P<0.01), and in the pyramidal layer, dimethyl-lysine 9 of H3 (H3K9me2) was decreased by 37% (P<0.05). These changes were region specific and were not observed in whole-brain preparations. Also, the same effects of CD on H3 methylation were observed in E14 neural progenitor cells (NPCs) in culture. Changes in G9a histone methyltransferase might mediate altered H3K9me2,1. Gene expression of G9a was decreased by 80% in CD NPCs (P<0.001). In CD, H3 was hypomethylated upstream of the RE1 binding site in the calbindin 1 promoter, and 1 CpG site within the calbindin1 promoter was hypermethylated. REST binding to RE1 (recruits G9a) was decreased by 45% (P<0.01) in CD. These changes resulted in increased expression of calbindin 1 in CD (260%; P<0.05). Thus, CD modulates histone methylation in NPCs, and this could underlie the observed changes in neurogenesis.

Background: Some humans fed a low-choline diet develop hepatosteatosis, liver and muscle damage, and lymphocyte apoptosis. The risk of developing such organ dysfunction is increased by the presence of single-nucleotide polymorphisms (SNPs) in genes involved in folate and choline metabolism., Objective: We investigated whether these changes that occur in the expression of many genes when humans are fed a low-choline diet differ between subjects who develop organ dysfunction and those who do not. We also investigated whether expression changes were dependent on the presence of the SNPs of interest., Design: Thirty-three subjects aged 20-67 y were fed for 10 d a baseline diet containing the recommended adequate intake of choline. They then were fed a low-choline diet for up to 42 d or until they developed organ dysfunction. Blood was collected at the end of each phase, and peripheral lymphocytes were isolated and used for genotyping and for gene expression profiling with the use of microarray hybridization., Results: Feeding a low-choline diet changed the expression of 259 genes, and the profiles of subjects who developed and those who did not develop signs of organ dysfunction differed. Group clustering and gene ontology analyses found that the diet-induced changes in gene expression profiles were significantly influenced by the SNPs of interest and that the gene expression phenotype of the variant gene carriers differed significantly even with the baseline diet., Conclusion: These findings support our hypothesis that a person's susceptibility to organ dysfunction when fed a low-choline diet is modulated by specific SNPs in genes involved in folate and choline metabolism.

Background: Whereas deficiency of the essential nutrient choline is associated with DNA damage and apoptosis in cell and rodent models, it has not been shown in humans., Objective: The objective was to ascertain whether lymphocytes from choline-deficient humans had greater DNA damage and apoptosis than did those from choline-sufficient humans., Design: Fifty-one men and women aged 18-70 y were fed a diet containing the recommended adequate intake of choline (control) for 10 d. They then were fed a choline-deficient diet for up to 42 d before repletion with 138-550 mg choline/d. Blood was collected at the end of each phase, and peripheral lymphocytes were isolated. DNA damage and apoptosis were then assessed by activation of caspase-3, terminal deoxynucleotide transferase-mediated dUTP nick end-labeling, and single-cell gel electrophoresis (COMET) assays., Results: All subjects fed the choline-deficient diet had lymphocyte DNA damage, as assessed by COMET assay, twice that found when they were fed the control diet. The subjects who developed organ dysfunction (liver or muscle) when fed the choline-deficient diet had significantly more apoptotic lymphocytes, as assessed by the activated caspase-3 assay, than when fed the control diet., Conclusions: A choline-deficient diet increased DNA damage in humans. Subjects in whom these diets induced liver or muscle dysfunction also had higher rates of apoptosis in their peripheral lymphocytes than did subjects who did not develop organ dysfunction. Assessment of DNA damage and apoptosis in lymphocytes appears to be a clinically useful measure in humans (such as those receiving parenteral nutrition) in whom choline deficiency is suspected.

Choline is an essential nutrient and an important methyl donor. Choline deficiency alters fetal development of the hippocampus in rodents and these changes are associated with decreased memory function lasting throughout life. Also, choline deficiency alters global and gene-specific DNA methylation in several models. This gene expression profiling study describes changes in cortical neural precursor cells from embryonic day 14 mice, after 48 h of exposure to a choline-deficient medium. Using Significance Analysis of Microarrays, we found the expression of 1003 genes to be significantly changed (from a total of 16,000 total genes spotted on the array), with a false discovery rate below 5%. A total of 846 genes were overexpressed while 157 were underexpressed. Classification by gene ontology revealed that 331 of these genes modulate cell proliferation, apoptosis, neuronal and glial differentiation, methyl metabolism, and calcium-binding protein classes. Twenty-seven genes that had changed expression have previously been reported to be regulated by promoter or intron methylation. These findings support our previous work suggesting that choline deficiency decreases the proliferation of neural precursors and possibly increases premature neuronal differentiation and apoptosis.