Interaction Between the PERK/ATF4 Branch of the Endoplasmic Reticulum Stress and Mitochondrial One-Carbon Metabolism Regulates Neuronal Survival After Intracerebral Hemorrhage.

Recent investigations have revealed that oxidative stress can lead to neuronal damage and disrupt mitochondrial and endoplasmic reticulum functions after intracerebral hemorrhage (ICH). However, there is limited evidence elucidating their role in maintaining neuronal homeostasis. Metabolomics analysis, RNA sequencing, and CUT&Tag-seq were performed to investigate the mechanism underlying the interaction between the PERK/ATF4 branch of the endoplasmic reticulum stress (ERS) and mitochondrial one-carbon (1C) metabolism during neuronal resistance to oxidative stress. The association between mitochondrial 1C metabolism and the PERK/ATF4 branch of the ERS after ICH was investigated using transcription factor motif analysis and co-immunoprecipitation. The findings revealed interactions between the GRP78/PERK/ATF4 and mitochondrial 1C metabolism, which are important in preserving neuronal homeostasis after ICH. ATF4 is an upstream transcription factor that directly regulates the expression of 1C metabolism genes. Additionally, the GRP78/PERK/ATF4 forms a negative regulatory loop with MTHFD2 because of the interaction between GRP78 and MTHFD2. This study presents evidence of disrupted 1C metabolism and the occurrence of ERS in neurons post-ICH. Supplementing exogenous NADPH or interfering with the PERK/ATF4 could reduce symptoms related to neuronal injuries, suggesting new therapeutic prospects for ICH.

Maternal Dietary Deficiency in Choline Reduced Levels of MMP-2 Levels in Blood and Brain Tissue of Male Offspring Mice.

Ischemic stroke is one of the leading causes of disability and death globally, with a rising incidence in younger age groups. It is well known that maternal diet during pregnancy and lactation is vital for the early neurodevelopment of offspring. One-carbon (1C) metabolism, including folic acid and choline, plays a vital role in closure of the neural tube in utero. However, the impact of maternal dietary deficiencies in 1C on offspring neurological function following ischemic stroke later in life remains undefined. The aim of this study was to investigate inflammation in the blood and brain tissue of offspring from mothers deficient in dietary folic acid or choline. Female mice were maintained on either a control or deficient diet prior to and during pregnancy and lactation. When offspring were 3 months of age, ischemic stroke was induced. One and a half months later, blood and brain tissue were collected. We measured levels of matrix metalloproteases (MMP)-2 and 9 in both plasma and brain tissue, and reported reduced levels of MMP-2 in ChDD male offspring in both tissue types. No changes were observed in MMP-9. This observation supports our working hypothesis that maternal dietary deficiencies in folic acid or choline during early neurodevelopment impact the levels of inflammation in offspring after ischemic stroke.

Maternal dietary deficiencies in folic acid or choline reduce primary neuron viability after exposure to hypoxia through increased levels of apoptosis.

Objective: Ischemic stroke is the leading cause of death and disability globally. By addressing modifiable risk factors, particularly nutrition, the prevalence of stroke and its dire consequences can be mitigated. One-carbon (1C) metabolism is a critical biosynthetic process that is involved in neural tube closure, DNA synthesis, plasticity, and cellular proliferation. Folates and choline are two active components of 1C metabolism. We have previously demonstrated that maternal dietary deficiencies during pregnancy and lactation in folic acid or choline result in worse stroke outcomes in offspring. However, there is insufficient data to understand the neuronal mechanisms involved.Methods: Using C57Bl/6J female mice maintained on control, folic acid (0.3 mg/kg) or choline (choline bitrate 300 mg/kg) deficient diets we collected embryonic primary neurons from offspring and exposed them to hypoxic conditions for 6 hours. To determine whether increased levels of either folic acid or choline can rescue reduced neuronal viability, we supplemented cell media with folic acid and choline prior to and after exposure to hypoxia.Results: Our results suggest that maternal dietary deficiencies in either folic acid or choline during pregnancy negatively impacts offspring neuronal viability after hypoxia. Furthermore, increasing levels of folic acid (250 mg/ml) or choline chloride (250 mg/ml) prior to and after hypoxia have a beneficial impact on neuronal viability.Conclusion: The findings contribute to our understanding of the intricate interplay between maternal dietary factors, 1C metabolism, and the outcome of offspring to hypoxic events, emphasizing the potential for nutritional interventions in mitigating adverse outcomes.

One-Carbon Metabolites Supplementation and Nutrient Restriction Alter the Fetal Liver Metabolomic Profile during Early Gestation in Beef Heifers.

Maternal nutrition is pivotal for proper fetal development, with one-carbon metabolites (OCM) playing a key role in fetal epigenetic programming through DNA and histone methylation. The study aimed to investigate the effects of nutrient restriction and OCM supplementation on fetal liver metabolomics in pregnant beef-heifers, focusing on metabolites and pathways associated with amino-acid, vitamin and cofactor, carbohydrate, and energy metabolism at day 63 of gestation. Thirty-one crossbred Angus heifers were artificially inseminated and allocated to four nutritional treatments in a 2 × 2 factorial arrangement of treatments, with the two factors being dietary intake/rate of gain (control-diet [CON]; 0.60 kg/day ADG, vs. restricted-diet [RES]; -0.23 kg/day ADG) and OCM supplementation (supplemented [+OCM] vs. not supplemented [-OCM]). The resulting treatment groups-CON-OCM, CON+OCM, RES-OCM, and RES+OCM were maintained for 63 days post-breeding. Following this period, fetal liver tissues were collected and subjected to metabolomic analysis using UPLC-tandem mass-spectrometry. We identified 288 metabolites, with the majority (n = 54) being significantly influenced by the main effect of gain (P ≤ 0.05). Moreover, RES showed decreased abundances of most metabolites in pathways such as lysine metabolism; leucine, isoleucine and valine metabolism; and tryptophan metabolism, compared to CON. Supplementation with OCM vs. no OCM supplementation, resulted in greater abundance of metabolites (P ≤ 0.05) affecting pathways associated with methionine, cysteine, S-adenosylmethionine and taurine metabolism; guanidino and acetamido metabolism; and nicotinate and nicotinamide metabolism. Notably, OCM supplementation with a moderate rate of gain increased the concentrations of ophthalmate, N-acetylglucosamine, and ascorbic-acid 3-sulfate, which are important for proper fetal development (P ≤ 0.05). Nutrient restriction reduced the majority of liver metabolites, while OCM supplementation increased a smaller number of metabolites. Thus, OCM supplementation may be protective of metabolite concentrations in key developmental pathways, which could potentially enhance fetal development under nutrient-restricted conditions.

Subcellular one carbon metabolism in cancer, aging and epigenetics.

The crosstalk between metabolism and epigenetics is an emerging field that is gaining importance in different areas such as cancer and aging, where changes in metabolism significantly impacts the cellular epigenome, in turn dictating changes in chromatin as an adaptive mechanism to bring back metabolic homeostasis. A key metabolic pathway influencing an organism's epigenetic state is one-carbon metabolism (OCM), which includes the folate and methionine cycles. Together, these cycles generate S-adenosylmethionine (SAM), the universal methyl donor essential for DNA and histone methylation. SAM serves as the sole methyl group donor for DNA and histone methyltransferases, making it a crucial metabolite for chromatin modifications. In this review, we will discuss how SAM and its byproduct, S-adenosylhomocysteine (SAH), along with the enzymes and cofactors involved in OCM, may function in the different cellular compartments, particularly in the nucleus, to directly regulate the epigenome in aging and cancer.

Unveiling the Therapeutic Potential of Folate-Dependent One-Carbon Metabolism in Cancer and Neurodegeneration.

Cellular metabolism is crucial for various physiological processes, with folate-dependent one-carbon (1C) metabolism playing a pivotal role. Folate, a B vitamin, is a key cofactor in this pathway, supporting DNA synthesis, methylation processes, and antioxidant defenses. In dividing cells, folate facilitates nucleotide biosynthesis, ensuring genomic stability and preventing carcinogenesis. Additionally, in neurodevelopment, folate is essential for neural tube closure and central nervous system formation. Thus, dysregulation of folate metabolism can contribute to pathologies such as cancer, severe birth defects, and neurodegenerative diseases. Epidemiological evidence highlights folate's impact on disease risk and its potential as a therapeutic target. In cancer, antifolate drugs that inhibit key enzymes of folate-dependent 1C metabolism and strategies targeting folate receptors are current therapeutic options. However, folate's impact on cancer risk is complex, varying among cancer types and dietary contexts. In neurodegenerative conditions, including Alzheimer's and Parkinson's diseases, folate deficiency exacerbates cognitive decline through elevated homocysteine levels, contributing to neuronal damage. Clinical trials of folic acid supplementation show mixed outcomes, underscoring the complexities of its neuroprotective effects. This review integrates current knowledge on folate metabolism in cancer and neurodegeneration, exploring molecular mechanisms, clinical implications, and therapeutic strategies, which can provide crucial information for advancing treatments.

SHIN-2 exerts potent activity against VanA-type vancomycin-resistant Enterococcus faecium in vitro by stabilizing the active site loop of serine hydroxymethyltransferase.

Novel classes of antibiotics are needed to improve the resilience of the healthcare system to antimicrobial resistance (AMR), including vancomycin resistance. vanA gene cluster is a cause of vancomycin resistance. This gene cluster is transferred and spreads vancomycin resistance from Enterococcus spp. to Staphylococcus aureus. Therefore, novel antibacterial agents are required to combat AMR, including vanA-type vancomycin resistance. Serine hydroxymethyltransferase (SHMT) is a key target of antibacterial agents. However, the specific binding mechanisms of SHMT inhibitors remain unclear. Detailed structural information will contribute to understanding these mechanisms. In this study, we found that (+)-SHIN-2, the first in vivo active inhibitor of human SHMT, is strongly bound to the Enterococcus faecium SHMT (efmSHMT). Comparison of the crystal structures of apo- and (+)-SHIN-2-boud efmSHMT revealed that (+)-SHIN-2 stabilized the active site loop of efmSHMT via hydrogen bonds, which are critical for efmSHMT inhibition. Additionally, (+)-SHIN-2 formed hydrogen bonds with serine, forming the Schiff's base with pyridoxal 5'-phosphate, which is a co-factor of SHMT. Furthermore, (+)-SHIN-2 exerted biostatic effects on vancomycin-susceptible and vanA-type vancomycin-resistant E. faecium in vitro, indicating that SHMT inhibitors do not induce cross-resistance to vanA-type vancomycin. Overall, these findings can aid in the design of novel SHMT inhibitors to combat AMR, including vancomycin resistance.

Expression patterns of folate metabolism-related enzymes in the bovine oviduct: estrous cycle-dependent modulation and responsiveness to folic acid.

Folate metabolism is required for important biochemical processes that regulate cell functioning, but its role in female reproductive physiology in cattle during peri- and post-conceptional periods has not been thoroughly explored. Previous studies have shown the presence of folate in bovine oviductal fluid, as well as finely regulated gene expression of folate receptors and transporters in bovine oviduct epithelial cells (BOECs). Additionally, extracellular folic acid (FA) affects the transcriptional levels of genes important for the functioning of BOECs. However, it remains unknown whether the anatomical and cyclic features inherent to the oviduct affect regulation of folate metabolism. The present study aimed to characterize the gene expression pattern of folate cycle enzymes in BOECs from different anatomical regions during the estrous cycle and to determine the transcriptional response of these genes to increasing concentrations of exogenous FA. A first PCR screening showed the presence of transcripts encoding dihydrofolate reductase (DHFR), methylenetetrahydrofolate reductase (MTHFR), and methionine synthase (MTR) in bovine reproductive tissues (ovary, oviduct and uterus), with expression levels in oviductal tissues comparable to, or even higher than, those detected in ovarian and uterine tissues. Moreover, expression analysis through RT-qPCR in BOECs from the ampulla and isthmus during different stages of the estrous cycle demonstrated that folate metabolism-related enzymes exhibited cycle-dependent variations. In both anatomical regions, DHFR was upregulated during the preovulatory stage, while MTHFR and MTR exhibited increased expression levels during the postovulatory stage. Under in vitro culture conditions, ampullary and isthmic cells were cultured in the presence of 10, 50, and 100 µM FA for 24 h. Under these conditions, isthmus epithelial cells exhibited a unique transcriptional response to exogenous FA, showing a pronounced increase in MTR expression levels. Our results suggest that the expression of folate metabolism-related genes in BOECs is differentially regulated during the estrous cycle and may respond to exogenous levels of folate. This offers a new perspective on the transcriptional regulation of genes associated with the folate cycle in oviductal cells and provides groundwork for future studies on their functional and epigenetic implications within the oviductal microenvironment.

Differential One-Carbon Metabolites among Children with Autism Spectrum Disorder: A Case-Control Study.

BACKGROUND: Driven by the complex multifactorial etiopathogenesis of autism spectrum disorder (ASD), a growing interest surrounds the disturbance in folate-dependent one-carbon metabolism (OCM) in the pathology of ASD, whereas the evidence remained inconclusive. OBJECTIVES: The study aims to investigate the association of OCM metabolism and ASD and characterize differential OCM metabolites among children with ASD. METHODS: Plasma OCM metabolites were investigated in 59 children with ASD and 40 neurotypical children using ultra-performance liquid chromatography tandem mass spectrometry technology. Differences (significance level < 0.001) were tested in each OCM metabolite between cases and controls. Multivariable models were also performed after adjusting for covariates. RESULTS: Ten out of 22 examined OCM metabolites were significantly different in children with ASD, compared with neurotypical controls. Specifically, S-adenosylmethionine (SAM), oxidized glutathione (GSSG), and glutathione (GSH) levels were increased, whereas S-adenosylhomocysteine (SAH), choline, glycine, L-serine, cystathionine, L-cysteine, and taurine levels were significantly decreased. Children with ASD showed significantly higher SAM/SAH ratio (3.87 ± 0.93 compared with 2.00 ± 0.76, P = 0.0001) and lower GSH/GSSG ratio [0.58 (0.46, 0.81) compared with 1.71 (0.93, 2.99)] compared with the neurotypical controls. Potential interactive effects between SAM/SAH ratio, taurine, L-serine, and gastrointestinal syndromes were further observed. CONCLUSIONS: OCM disturbance was observed among children with ASD, particularly in methionine methylation and trans-sulfuration pathways. The findings add valuable insights into the mechanisms underlying ASD and the potential of ameliorating OCM as a promising therapeutic of ASD, which warrant further validation.

Serine and glycine physiology reversibly modulate retinal and peripheral nerve function.

Metabolic homeostasis is maintained by redundant pathways to ensure adequate nutrient supply during fasting and other stresses. These pathways are regulated locally in tissues and systemically via the liver, kidney, and circulation. Here, we characterize how serine, glycine, and one-carbon (SGOC) metabolism fluxes across the eye, liver, and kidney sustain retinal amino acid levels and function. Individuals with macular telangiectasia (MacTel), an age-related retinal disease with reduced circulating serine and glycine, carrying deleterious alleles in SGOC metabolic enzymes exhibit an exaggerated reduction in circulating serine. A Phgdh+/- mouse model of this haploinsufficiency experiences accelerated retinal defects upon dietary serine/glycine restriction, highlighting how otherwise silent haploinsufficiencies can impact retinal health. We demonstrate that serine-associated retinopathy and peripheral neuropathy are reversible, as both are restored in mice upon serine supplementation. These data provide molecular insights into the genetic and metabolic drivers of neuro-retinal dysfunction while highlighting therapeutic opportunities to ameliorate this pathogenesis.