Baylor Institute of Metabolic Disease

Panetta, J.C., Liu, Y., Bottiglieri, T., Arning, E., Cheng, C., Karol, S.E., Yang, J.J., Zhou, Y., Inaba, H., Pui, C.H., Jeha, S. and Relling, M.V. (2021). “Pharmacodynamics of cerebrospinal fluid asparagine after asparaginase.” Cancer Chemother Pharmacol Jun 25. [Epub ahead of print].

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PURPOSE: We evaluated effects of asparaginase dosage, schedule, and formulation on CSF asparagine in children with acute lymphoblastic leukemia (ALL). METHODS: We evaluated CSF asparagine (2114 samples) and serum asparaginase (5007 samples) in 482 children with ALL treated on the Total XVI study (NCT00549848). Patients received one or two 3000 IU/m(2) IV pegaspargase doses during induction and were then randomized in continuation to receive 2500 IU/m(2) or 3500 IU/m(2) IV intermittently (four doses) on the low-risk (LR) or continuously (15 doses) on the standard/high risk (SHR) arms. A pharmacokinetic-pharmacodynamic model was used to estimate the duration of CSF asparagine depletion below 1 uM. RESULTS: During induction, CSF asparagine depletion after two doses of pegaspargase was twice as long as one dose (median 30.7 vs 15.3 days, p < 0.001). During continuation, the higher dose increased the CSF asparagine depletion duration by only 9% on the LR and 1% in the SHR arm, consistent with the nonlinear pharmacokinetics of serum asparaginase. Pegaspargase caused a longer CSF asparagine depletion duration (1.3-5.3-fold) compared to those who were switched to erwinase (p < 0.001). The median (quartile range) serum asparaginase activity needed to maintain CSF asparagine below 1 µM was 0.44 (0.20, 0.99) IU/mL. Although rare, CNS relapse was higher with decreased CSF asparagine depletion (p = 0.0486); there was no association with relapse at any site (p = 0.3). CONCLUSIONS: The number of pegaspargase doses has a stronger influence on CSF asparagine depletion than did dosage, pegaspargase depleted CSF asparagine longer than erwinase, and CSF asparagine depletion may prevent CNS relapses.

Luan, Y., Leclerc, D., Cosín-Tomás, M., Malysheva, O.V., Wasek, B., Bottiglieri, T., Caudill, M.A. and Rozen, R. (2021). “Moderate Folic Acid Supplementation in Pregnant Mice Results in Altered Methyl Metabolism and in Sex-specific Placental Transcription Changes.” Mol Nutr Food Res May 19;e2100197. [Epub ahead of print]. e2100197.

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SCOPE: Many pregnant women have higher folic acid (FA) intake due to food fortification and increased vitamin use. We reported that diets containing 5-fold higher FA than recommended for mice (5xFASD) during pregnancy, resulted in methylenetetrahydrofolate reductase (MTHFR) deficiency and altered choline/methyl metabolism, with neurobehavioral abnormalities in newborns. Our goal was to determine whether these changes had their origins in the placenta during embryonic development. METHODS AND RESULTS: Female mice were fed control diet (CD) or 5xFASD for a month before mating and maintained on these diets until embryonic day 17.5. 5xFASD led to pseudo-MTHFR deficiency in maternal liver and altered choline/methyl metabolites in maternal plasma (increased methyltetrahydrofolate and decreased betaine). Methylation potential (S-adenosylmethionine: S-adenosylhomocysteine ratio) and glycerophosphocholine were decreased in placenta and embryonic liver. FASD resulted in sex-specific transcriptome profiles in placenta, with validation of dietary expression changes of 29 genes involved in angiogenesis, receptor biology or neurodevelopment, and altered methylation of the serotonin receptor 2A gene. CONCLUSION: Moderate increases in folate intake during pregnancy result in placental metabolic and gene expression changes, particularly in angiogenesis, which may contribute to abnormal behavior in pups. These results are relevant for determining a safe upper limit for folate intake during pregnancy.

Gupta, S., Wang, L., Slifker, M.J., Cai, K.Q., Maclean, K.N., Wasek, B., Bottiglieri, T. and Kruger, W.D. (2021). “Analysis of differential neonatal lethality in cystathionine β-synthase deficient mouse models using metabolic profiling.” Faseb j 35(6): e21629.

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Cystathionine beta-synthase (CBS) is a key enzyme of the trans-sulfuration pathway that converts homocysteine to cystathionine. Loss of CBS activity due to mutation results in CBS deficiency, an inborn error of metabolism characterized by extreme elevation of plasma total homocysteine (tHcy). C57BL6 mice containing either a homozygous null mutation in the cystathionine β-synthase (Cbs(-/-) ) gene or an inactive human CBS protein (Tg-G307S Cbs(-/-) ) are born in mendelian numbers, but the vast majority die between 18 and 21 days of age due to liver failure. However, adult Cbs null mice that express a hypomorphic allele of human CBS as a transgene (Tg-I278T Cbs(-/-) ) show almost no neonatal lethality despite having serum tHcy levels similar to mice with no CBS activity. Here, we characterize liver and serum metabolites in neonatal Cbs(+/-) , Tg-G307S Cbs(-/-) , and Tg-I278T Cbs(-/-) mice at 6, 10, and 17 days of age to understand this difference. In serum, we observe similar elevations in tHcy in both Tg-G307S Cbs(-/-) and Tg-I278T Cbs(-/-) compared to control animals, but methionine is much more severely elevated in Tg-G307S Cbs(-/-) mice. Large scale metabolomic analysis of liver tissue confirms that both methionine and methionine-sulfoxide are significantly more elevated in Tg-G307S Cbs(-/-) animals, along with significant differences in several other metabolites including hexoses, amino acids, other amines, lipids, and carboxylic acids. Our data are consistent with a model that the neonatal lethality observed in CBS-null mice is driven by excess methionine resulting in increased stress on a variety of related pathways including the urea cycle, TCA cycle, gluconeogenesis, and phosphatidylcholine biosynthesis.

Pannia, E., Hammoud, R., Kubant, R., Sa, J.Y., Simonian, R., Wasek, B., Ashcraft, P., Bottiglieri, T., Pausova, Z. and Anderson, G.H. (2021). “High Intakes of [6S]-5-Methyltetrahydrofolic Acid Compared with Folic Acid during Pregnancy Programs Central and Peripheral Mechanisms Favouring Increased Food Intake and Body Weight of Mature Female Offspring.” Nutrients 13(5).

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Supplementation with [6S]-5-methyltetrahydrofolic acid (MTHF) is recommended as an alternative to folic acid (FA) in prenatal supplements. This study compared equimolar gestational FA and MTHF diets on energy regulation of female offspring. Wistar rats were fed an AIN-93G diet with recommended (2 mg/kg diet) or 5-fold (5X) intakes of MTHF or FA. At weaning, female offspring were fed a 45% fat diet until 19 weeks. The 5X-MTHF offspring had higher body weight (>15%), food intake (8%), light-cycle energy expenditure, and lower activity compared to 5X-FA offspring (p < 0.05). Both the 5X offspring had higher plasma levels of the anorectic hormone leptin at birth (60%) and at 19 weeks (40%), and lower liver weight and total liver lipids compared to the 1X offspring (p < 0.05). Hypothalamic mRNA expression of leptin receptor (ObRb) was lower, and of suppressor of cytokine signaling-3 (Socs3) was higher in the 5X-MTHF offspring (p < 0.05), suggesting central leptin dysregulation. In contrast, the 5X-FA offspring had higher expression of genes encoding for dopamine and GABA- neurotransmitter receptors (p < 0.01), consistent with their phenotype and reduced food intake. When fed folate diets at the requirement level, no differences were found due to form in the offspring. We conclude that MTHF compared to FA consumed at high levels in the gestational diets program central and peripheral mechanisms to favour increased weight gain in the offspring. These pre-clinical findings caution against high gestational intakes of folates of either form and encourage clinical trials examining their long-term health effects when consumed during pregnancy.

Hammoud, R., Pannia, E., Kubant, R., Wasek, B., Bottiglieri, T., Malysheva, O.V., Caudill, M.A. and Anderson, G.H. (2021). “Choline and Folic Acid in Diets Consumed during Pregnancy Interact to Program Food Intake and Metabolic Regulation of Male Wistar Rat Offspring.” J Nutr 151(4): 857-865.

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BACKGROUND: North American women consume high folic acid (FA), but most are not meeting the adequate intakes for choline. High-FA gestational diets induce an obesogenic phenotype in rat offspring. It is unclear if imbalances between FA and other methyl-nutrients (i.e., choline) account for these effects. OBJECTIVE: This study investigated the interaction of choline and FA in gestational diets on food intake, body weight, one-carbon metabolism, and hypothalamic gene expression in male Wistar rat offspring. METHODS: Pregnant Wistar rats were fed an AIN-93G diet with recommended choline and FA [RCRF; 1-fold, control] or high (5-fold) FA with choline at 0.5-fold [low choline and high folic acid (LCHF)], 1-fold [recommended choline and high folic acid (RCHF)], or 2.5-fold [high choline and high folic acid (HCHF)]. Male offspring were weaned to an RCRF diet for 20 wk. Food intake, weight gain, plasma energy-regulatory hormones, brain and plasma one-carbon metabolites, and RNA sequencing (RNA-seq) in pup hypothalamuses were assessed. RESULTS: Adult offspring from LCHF and RCHF, but not HCHF, gestational diets had 10% higher food intake and weight gain than controls (P < 0.01). HCHF newborn pups had lower plasma insulin and leptin compared with LCHF and RCHF pups (P < 0.05), respectively. Pup brain choline (P < 0.05) and betaine (P < 0.01) were 22-33% higher in HCHF pups compared with LCHF pups; methionine was ∼23% lower after all high FA diets compared with RCRF (P < 0.01). LCHF adult offspring had lower brain choline (P < 0.05) than all groups and lower plasma 5-methyltetrahydrofolate (P < 0.05) than RCRF and RCHF groups. HCHF adult offspring had lower plasma cystathionine (P < 0.05) than LCHF adult offspring and lower homocysteine (P < 0.01) than RCHF and RCRF adult offspring. RNA-seq identified 144 differentially expressed genes in the hypothalamus of HCHF newborns compared with controls. CONCLUSIONS: Increased choline in gestational diets modified the programming effects of high FA on long-term food intake regulation, plasma energy-regulatory hormones, one-carbon metabolism, and hypothalamic gene expression in male Wistar rat offspring, emphasizing a need for more attention to the choline and FA balance in maternal diets.