One-Carbon Metabolism: Pulling the Strings behind Aging and Neurodegeneration

The epigenetic approach of varicocele: a focus on sperm DNA and m6A-RNA methylation

BACKGROUND

Varicocele is an abnormal dilation and torsion of the pampiniform venous plexus in the scrotum due to venous reflux, primarily affecting the left side. It affects 15% of men and is a prevalent contributor to male infertility. Varicocele is a complex disorder influenced by genetic, epigenetic, and environmental factors. Epigenetic modifications, which regulate genome activity independently of DNA or RNA sequences, may contribute to the development and severity of varicocele. These include DNA methylation, histone modifications, and RNA modifications like N6-methyladenosine (m6A). Irregularities in DNA and m6A-RNA methylation during spermatogenesis can cause gene expression abnormalities, DNA damage, and decreased fertility in varicocele patients.

OBJECTIVE AND RATIONALE

The review aims to comprehensively understand the underlying mechanisms of varicocele, a condition that can significantly impact male fertility. By exploring the role of methylation modifications, specifically DNA and m6A-RNA methylation, the review aims to synthesize evidence from basic, preclinical, and clinical research to expand the existing knowledge on this subject. The ultimate goal is to identify potential avenues for developing targeted treatments that can effectively improve varicocele and ultimately increase sperm quality in affected individuals.

SEARCH METHODS

A thorough investigation of the scientific literature was conducted through searches in PubMed, Google Scholar, and Science Direct databases until May 2024. All studies investigating the relationship between DNA and m6A-RNA methylation and male infertility, particularly varicocele were reviewed, and the most pertinent reports were included. Keywords such as varicocele, epigenetics, DNA methylation, m6A-RNA methylation, hypermethylation, hypomethylation, spermatozoa, semen parameters, spermatogenesis, and male infertility were used during the literature search, either individually or in combination.

OUTCOMES

The sperm has a specialized morphology essential for successful fertilization, and its epigenome is unique, potentially playing a key role in embryogenesis. Sperm DNA and RNA methylation, major epigenetic marks, regulate the expression of testicular genes crucial for normal spermatogenesis. This review explores the role of DNA and m6A-RNA methylation, in responding to oxidative stress and how various nutrients influence their function in varicocele condition. Evidence suggests a potential link between varicocele and aberrant DNA/m6A-RNA methylation patterns, especially hypomethylation, but the body of evidence is still limited. Further studies are needed to understand how abnormal expression of DNA/m6A-RNA methylation regulators affects testicular gene expression. Thus, analyzing sperm DNA 5mC/5hmC levels and m6A-RNA methylation regulators may reveal spermatogenesis defects and predict reproductive outcomes.

WIDER IMPLICATIONS

Nutri-epigenomics is an emerging field that could enhance the knowledge and management of diseases with unpredictable risks and consequences, even among individuals with similar lifestyles, by elucidating the influence of nutrition on DNA/m6A-RNA methylation through one-carbon metabolism. However, the importance of one-carbon metabolism to varicocele is not well-recognized. Health status and diet influence one-carbon metabolism and its associated DNA/m6A-RNA methylation modification. Future research should identify optimal methylation patterns that promote health and investigate modulating one-carbon metabolism to achieve this. Furthermore, additional studies are necessary to develop personalized dietary strategies through clinical and longitudinal research. However, a research gap exists on dietary interventions utilizing epigenetics as a therapeutic method for treating varicocele.

REGISTRATION NUMBER

Not applicable.

Enhancing mitochondrial one-carbon metabolism is neuroprotective in Alzheimer's disease models

Alzheimer's disease (AD) is the most common form of age-related dementia. In AD, the death of neurons in the central nervous system is associated with the accumulation of toxic amyloid β peptide (Aβ) and mitochondrial dysfunction. Mitochondria are signal transducers of metabolic and biochemical information, and their impairment can compromise cellular function. Mitochondria compartmentalise several pathways, including folate-dependent one-carbon (1C) metabolism and electron transport by respiratory complexes. Mitochondrial 1C metabolism is linked to electron transport through complex I of the respiratory chain. Here, we analysed the proteomic changes in a fly model of AD by overexpressing a toxic form of Aβ (Aβ-Arc). We found that expressing Aβ-Arc caused alterations in components of both complex I and mitochondrial 1C metabolism. Genetically enhancing mitochondrial 1C metabolism through Nmdmc improved mitochondrial function and was neuroprotective in fly models of AD. We also found that exogenous supplementation with the 1C donor folinic acid improved mitochondrial health in both mammalian cells and fly models of AD. We found that genetic variations in MTHFD2L, the human orthologue of Nmdmc, were linked to AD risk. Additionally, Mendelian randomisation showed that increased folate intake decreased the risk of developing AD. Overall, our data suggest enhancement of folate-dependent 1C metabolism as a viable strategy to delay the progression and attenuate the severity of AD.

20-Hydroxyecdysone Boosts Energy Production and Biosynthetic Processes in Non-Transformed Mouse Cells

20-Hydroxyecdysone (20E) is an arthropod steroid hormone that possesses a number of beneficial pharmacological activities in humans, including anabolic, antioxidant, hypoglycemic, cardioprotective, hepatoprotective, neuroprotective, and antineoplastic properties, etc. While several studies have explored the anabolic activity of 20E in muscle cells, they have concentrated on its effects on myofibril size, protein biosynthesis intensity, and myostatin expression, without assessing energy metabolism. In this research, we have demonstrated that 20E boosts both catabolism and anabolism, coupling energy-producing and biosynthetic metabolic processes in mouse myoblasts and fibroblasts in the same way. Using a transcriptomic approach, we identified the 20E-mediated up-regulation of genes involved in different metabolic processes. Further experiments revealed that 20E increased the levels of enzymes involved in glycolysis and one-carbon metabolism. It also increased the uptake of glucose, glycolysis, respiration, the production of ATP, and global protein biosynthesis in mouse myoblasts and fibroblasts. This phenomenon involves the PI3K/AKT/mTOR signaling pathway. Taken together, the observed 20E-dependent upregulation of energy metabolism may be the main reason for 20E's well-known anabolic activity.

The methionine cycle and its cancer implications

The essential amino acid methionine is a crucial regulator of sulfur metabolism in a variety of interconnected biochemical pathways. The methionine cycle is intricately linked to the folate cycle, forming the one-carbon metabolism, a crucial regulator of S-adenosylmethionine, SAM. Recent work highlights methionine's critical role in tumor growth and progression, maintaining polyamine synthesis, and playing a crucial role in the regulation of SAM both in altered chromatin states, depending on p53 status, as well as facilitating m6A methylation of NR4A2 mRNA, hence regulating proliferation in esophageal carcinoma. Accordingly, Celecoxib, a specific NR4A2 inhibitor, is a potentially powerful inhibitor of tumor growth at least in this specific model. Additionally, formaldehyde, from endogenous or exogenous sources, can directly regulate both SAM steady-state-levels and the one-carbon metabolism, with relevant implication in cancer progression. These recent scientific advancements have provided a deeper understanding of the molecular mechanisms involved in cancer development, and its potential therapeutic regulation.

The Pivotal Role of One-Carbon Metabolism in Neoplastic Progression During the Aging Process

One-carbon (1C) metabolism is a complex network of metabolic reactions closely related to producing 1C units (as methyl groups) and utilizing them for different anabolic processes, including nucleotide synthesis, methylation, protein synthesis, and reductive metabolism. These pathways support the high proliferative rate of cancer cells. While drugs that target 1C metabolism (like methotrexate) have been used for cancer treatment, they often have significant side effects. Therefore, developing new drugs with minimal side effects is necessary for effective cancer treatment. Methionine, glycine, and serine are the main three precursors of 1C metabolism. One-carbon metabolism is vital not only for proliferative cells but also for non-proliferative cells in regulating energy homeostasis and the aging process. Understanding the potential role of 1C metabolism in aging is crucial for advancing our knowledge of neoplastic progression. This review provides a comprehensive understanding of the molecular complexities of 1C metabolism in the context of cancer and aging, paving the way for researchers to explore new avenues for developing advanced therapeutic interventions for cancer.

Nanoparticles mediated folic acid enrichment

Folate is an essential component of many metabolic processes, and folate deficiency is known to cause various disorders. Folate and folic acid, a synthetic and chemically stable form of folate, enriched diet are typically used to overcome this deficiency. Folic acid and folate however, are susceptible to harsh environment and folates enrichment using nanoparticles is an intensively studied strategy in food industry. This review highlights the current methods and types of matrices utilized to develop folic acid/folate carrying nanoparticles. The folic acid/folate loaded nanoparticles prevent cargo degradation during gut absorption and under harsh food processing conditions including, high temperatures, UV light, and autoclaving. The data demonstrates that nanofortifcation of folates using proteins and biopolymers effectively enhances the bioavailability of the cargo. The encapsulation of folic acid in biopolymers by emulsion, spray drying and ionic gelation represent simplistic methods that can be easily scaled up with applications in food industry.

Senescence Reprogramming by MTHFD2 Deficiency Facilitates Tumor Progression

Background: Age is a critical risk factor for cancer, as its incidence and mortality increase with age. However, there is limited understanding of the molecular changes aging induces in tumors. Methods: We explored demographic differences between young and old cancer patients and identified age sixty and above as pivotal in cancer prognosis. Subsequently, we developed an aging-related prognostic model based on genes to assess senescence's impact on aging-associated cancer. Grounded in the coefficients and expression levels of these identified signature genes, a risk score was computed, enabling the classification of collected samples into aging-related high-risk and low-risk cohorts. Results: Our study revealed increased genomic instability and somatic mutations in tumors from older individuals. We also found alterations in carcinogenic signaling pathways, particularly immune responses, inflammatory pathways, and cell cycle arrest in susceptible populations. Single-cell RNA sequencing showed heightened frequencies of exhausted T cells, myeloid cells, and B cells in high-risk cohorts. Conclusion: MTHFD2 emerged as a crucial molecular switch regulating senescence in cancer. Its deletion promoted tumor growth by inducing cell senescence and stimulating the senescence-associated secretory phenotype (SASP) in senescent tumor cells. This highlights the need for tailored methodologies in effective cancer management.

Multicohort Epigenome-Wide Association Study of All-Cause Cardiovascular Disease and Cancer Incidence: A Cardio-Oncology Approach

Background

Emerging evidence reveals a complex relationship between cardiovascular disease (CVD) and cancer, which share common risk factors and biological pathways.

Objectives

The aim of this study was to evaluate common epigenetic signatures for CVD and cancer incidence in 3 ethnically diverse cohorts: Native Americans from the SHS (Strong Heart Study), European Americans from the FHS (Framingham Heart Study), and European Americans and African Americans from the ARIC (Atherosclerosis Risk In Communities) study.

Methods

A 2-stage strategy was used that included first conducting untargeted epigenome-wide association studies for each cohort and then running targeted models in the union set of identified differentially methylated positions (DMPs). We also explored potential molecular pathways by conducting a bioinformatics analysis.

Results

Common DMPs were identified across all populations. In a subsequent meta-analysis, 3 and 1 of those DMPs were statistically significant for CVD only and both cancer and CVD, respectively. No meta-analyzed DMPs were statistically significant for cancer only. The enrichment analysis pointed to interconnected biological pathways involved in cancer and CVD. In the DrugBank database, elements related to 1-carbon metabolism and cancer and CVD medications were identified as potential drugs for target gene products. In an additional analysis restricted to the 950 SHS participants who developed incident CVD, the C index for incident cancer increased from 0.618 (95% CI: 0.570-0.672) to 0.971 (95% CI: 0.963-0.978) when adjusting the models for the combined cancer and CVD DMPs identified in the other cohorts.

Conclusions

These results point to molecular pathways and potential treatments for precision prevention of CVD and cancer. Screening based on common epigenetic signatures of incident CVD and cancer may help identify patients with newly diagnosed CVD at increased cancer risk.

Traditional Korean diet high in one-carbon nutrients increases global DNA methylation: implication for epigenetic diet

PURPOSE

DNA methylation is a major epigenetic phenomenon through which diet affects health and disease. This study aimed to determine the epigenetic influence of the traditional Korean diet (K-diet) on global DNA methylation via one-carbon metabolism.

METHODS

A crossover study was conducted on 52 women. Two diets, a K-diet, high in plant foods and low in calories and animal fat, and a control diet, similar to the diet currently consumed in Korea, were provided to all subjects alternately for 4 weeks with a 4-week washout period. Clinical parameters were measured before and after each dietary intervention. Nutrient intake was calculated by using a computer-aided nutritional analysis program. One-carbon metabolites in the serum and global DNA methylation in peripheral mononuclear cells were determined using ultra-performance liquid chromatography-tandem mass spectrometry.

RESULTS

The K-diet group consumed more folate (669.9 ± 6.7 µg vs. 502.7 ± 3.0, p < 0.001), B6, B12, serine, and choline, and less methionine (992.6 ± 63 vs. 1048.3 mg ± 34.1, p < 0.0001) than the control group did. In the K-diet group, the increment of plasma 5-methyltetrahydrofolate (0.08 µg/mL ± 0.11 vs 0.02 ± 0.10, p < 0.009) and decrement of L-homocysteine (- 70.7 ± 85.0 vs - 39.3 ± 69.4, p < 0.0168) were greater than those of the control group. Global DNA methylation was significantly increased in the K-diet group (6.70 ± 3.02% to 9.45 ± 3.69, p < 0.0001) but not in the control group.

CONCLUSIONS

A K-diet high in one-carbon nutrients can enhance the global DNA methylation status, suggesting an epigenetic mechanism by which the K-diet conveys health effects. Trial registration Korean Clinical Trial Registry (trial number: KCT0005340, 24/08/2020, retrospectively registered).

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.

Associations of circulating vitamins with 10-year retinal neurodegeneration: the Alienor Study

OBJECTIVE

To investigate the associations between circulating vitamins A, D, E, B6, B9, B12 and longitudinal changes in retinal nerve fiber layer (RNFL) thickness.

METHODS

The Alienor study, a prospective population-based cohort (Bordeaux, France), includes 963 individuals aged 73 years or older at baseline. The present study included 646 participants with complete RNFL measurement and vitamins. Study period is from 2009 to 2020. Peripapillary RNFL thickness was measured using spectral domain optical coherence tomography (SD-OCT). Plasma vitamins A, D and E and, serum vitamins B6, B9 and B12 were measured from blood sample. We performed linear mixed models, adjusted for age, gender, axial length, family history of glaucoma, and alcohol consumption to evaluated associations between vitamins and RNFL thickness changes over time.

RESULTS

Individuals having higher concentrations of vitamin E, D and B9 had a slower RNFL thinning during the 10-years of follow-up. Indeed, a 1-standard deviation (SD) increase of vitamin E (10.8 μmol/L), D (17.6 nmol/L) and B9 (11 μmol/L) were associated with slower RNFL thinning by 0.14 μm/year (95% confidence interval (CI), 0.03-0.25, p = 0.01), 0.14 μm/year (95% CI, 0.02-0.27, p = 0.02) and 0.11 μm/year (95% CI: 0.007-0.21, p = 0.04), respectively. No significant associations were observed for vitamins A, B6 and B12 with RNFL thinning.

CONCLUSIONS

Higher levels of vitamins E, D and B9 were associated with a slower RNFL thickness on SD-OCT over time, suggesting that those vitamins may contribute to the neuroprotection of the retina.

Flavin-containing monooxygenase (FMO): Beyond xenobiotics

Flavin-containing monooxygenases (FMOs), traditionally known for detoxifying xenobiotics, are now recognized for their involvement in endogenous metabolism. We recently discovered that an isoform of FMO, fmo-2 in Caenorhabditis elegans, alters endogenous metabolism to impact longevity and stress tolerance. Increased expression of fmo-2 in C. elegans modifies the flux through the key pathway known as One Carbon Metabolism (OCM). This modified flux results in a decrease in the ratio of S-adenosyl-methionine (SAM) to S-adenosyl-homocysteine (SAH), consequently diminishing methylation capacity. Here we discuss how FMO-2-mediated formate production during tryptophan metabolism may serve as a trigger for changing the flux in OCM. We suggest formate bridges tryptophan and OCM, altering metabolic flux away from methylation during fmo-2 overexpression. Additionally, we highlight how these metabolic results intersect with the mTOR and AMPK pathways, in addition to mitochondrial metabolism. In conclusion, the goal of this essay is to bring attention to the central role of FMO enzymes but lack of understanding of their mechanisms. We justify a call for a deeper understanding of FMO enzyme's role in metabolic rewiring through tryptophan/formate or other yet unidentified substrates. Additionally, we emphasize the identification of novel drugs and microbes to induce FMO activity and extend lifespan.

Association of Methyl Donor Nutrients' Dietary Intake and Cognitive Impairment in the Elderly Based on the Intestinal Microbiome

Globally, cognitive impairment (CI) is the leading cause of disability and dependency among the elderly, presenting a significant public health concern. However, there is currently a deficiency in pharmacological interventions that can effectively cure or significantly reverse the progression of cognitive impairment. Methyl donor nutrients (MDNs), including folic acid, choline, and vitamin B12, have been identified as potential enhancers of cognitive function. Nevertheless, there remains a dearth of comprehensive research investigating the connection between the dietary intake of MDNs and CI. In our study, we comprehensively assessed the relationship between MDNs' dietary intake and CI in older adults, utilizing 16S rRNA gene sequencing to investigate the potential underlying mechanisms. The results showed an obvious difference in the methyl-donor nutritional quality index (MNQI) between the dementia (D) group and the dementia-free (DF) group. Specifically, there was a lower MNQI in the D group than that in the DF group. For the gut microbiome, the beta diversity of gut flora exhibited higher levels in the high methyl-donor nutritional quality (HQ) group as opposed to the low methyl-donor nutritional quality (LQ) group, and lower levels in the D group in comparison to the DF group. Subsequently, we performed a correlation analysis to examine the relationship between the relative abundance of microbiota, the intake of MDNs, and Montreal Cognitive Assessment (MoCA) scores, ultimately identifying ten genera with potential regulatory functions. Additionally, KEGG pathway analyses suggested that the one-carbon metabolism, chronic inflammation, and DNA synthesis potentially serve as pathways through which MDNs may be promising for influencing cognitive function. These results implied that MDNs might have the potential to enhance cognitive function through the regulation of microbiota homeostasis. This study offers dietary recommendations for the prevention and management of CI in the elderly.

Long-term NMN treatment increases lifespan and healthspan in mice in a sex dependent manner

Nicotinamide adenine dinucleotide (NAD) is essential for many enzymatic reactions, including those involved in energy metabolism, DNA repair and the activity of sirtuins, a family of defensive deacylases. During aging, levels of NAD + can decrease by up to 50% in some tissues, the repletion of which provides a range of health benefits in both mice and humans. Whether or not the NAD + precursor nicotinamide mononucleotide (NMN) extends lifespan in mammals is not known. Here we investigate the effect of long-term administration of NMN on the health, cancer burden, frailty and lifespan of male and female mice. Without increasing tumor counts or severity in any tissue, NMN treatment of males and females increased activity, maintained more youthful gene expression patterns, and reduced overall frailty. Reduced frailty with NMN treatment was associated with increases in levels of Anerotruncus colihominis, a gut bacterium associated with lower inflammation in mice and increased longevity in humans. NMN slowed the accumulation of adipose tissue later in life and improved metabolic health in male but not female mice, while in females but not males, NMN increased median lifespan by 8.5%, possible due to sex-specific effects of NMN on NAD + metabolism. Together, these data show that chronic NMN treatment delays frailty, alters the microbiome, improves male metabolic health, and increases female mouse lifespan, without increasing cancer burden. These results highlight the potential of NAD + boosters for treating age-related conditions and the importance of using both sexes for interventional lifespan studies.

Association of methyl donor nutrients dietary intake and sleep disorders in the elderly revealed by the intestinal microbiome

Currently, sleep disorders (SD) in the elderly are gaining prominence globally and are becoming a significant public health concern. Methyl donor nutrients (MDNs), such as vitamin B6, vitamin B12, folate, and choline, have been reported to have the potential to improve sleep disorders. Moreover, MDNs help to maintain gut flora homeostasis, and are closely associated with the development of SD. Nevertheless, there has been a lack of comprehensive human studies examining the association between MDNs intake and SD. In our study, we comprehensively evaluated the association between MDNs intake and SD in the elderly and used 16S rRNA gene sequencing to explore the underlying mechanism. We found that the SD group (n = 91) had a lower methyl-donor nutritional quality index (MNQI) and a trend toward lower intake compared to the control group (n = 147). Based on the intestinal microbiome, the beta diversity of the intestinal flora was higher in the high methyl-donor nutritional quality (HQ) group compared to the low methyl-donor nutritional quality (LQ) group, and it was lower in the SD group compared to the control group. This suggests that MDNs may regulate sleep by modulating the abundance distribution of the microbiota. Subsequently, we performed correlation analyses between the relative abundance of the microbiota, MDNs intake, and the Pittsburgh Sleep Quality Index (PSQI), identifying five genera with potential regulatory roles. The KEGG pathway analysis indicated that energy metabolism and one-carbon metabolism might be the pathways through which MDNs modulate sleep. This study offers dietary guidance strategies for managing SD in the elderly and provides insights for targeted microbiota intervention.

Mitochondrial One-Carbon Metabolism and Alzheimer's Disease

Mitochondrial one-carbon metabolism provides carbon units to several pathways, including nucleic acid synthesis, mitochondrial metabolism, amino acid metabolism, and methylation reactions. Late-onset Alzheimer's disease is the most common age-related neurodegenerative disease, characterised by impaired energy metabolism, and is potentially linked to mitochondrial bioenergetics. Here, we discuss the intersection between the molecular pathways linked to both mitochondrial one-carbon metabolism and Alzheimer's disease. We propose that enhancing one-carbon metabolism could promote the metabolic processes that help brain cells cope with Alzheimer's disease-related injuries. We also highlight potential therapeutic avenues to leverage one-carbon metabolism to delay Alzheimer's disease pathology.

From Environment to Gene Expression: Epigenetic Methylations and One-Carbon Metabolism in Amyotrophic Lateral Sclerosis

The etiology of the neurodegenerative disease amyotrophic lateral sclerosis (ALS) is complex and considered multifactorial. The majority of ALS cases are sporadic, but familial cases also exist. Estimates of heritability range from 8% to 61%, indicating that additional factors beyond genetics likely contribute to ALS. Numerous environmental factors are considered, which may add up and synergize throughout an individual's lifetime building its unique exposome. One level of integration between genetic and environmental factors is epigenetics, which results in alterations in gene expression without modification of the genome sequence. Methylation reactions, targeting DNA or histones, represent a large proportion of epigenetic regulations and strongly depend on the availability of methyl donors provided by the ubiquitous one-carbon (1C) metabolism. Thus, understanding the interplay between exposome, 1C metabolism, and epigenetic modifications will likely contribute to elucidating the mechanisms underlying altered gene expression related to ALS and to developing targeted therapeutic interventions. Here, we review evidence for 1C metabolism alterations and epigenetic methylation dysregulations in ALS, with a focus on the impairments reported in neural tissues, and discuss these environmentally driven mechanisms as the consequences of cumulative exposome or late environmental hits, but also as the possible result of early developmental defects.

SHMT2 Mediates Small-Molecule-Induced Alleviation of Alzheimer Pathology Via the 5'UTR-dependent ADAM10 Translation Initiation

It is long been suggested that one-carbon metabolism (OCM) is associated with Alzheimer's disease (AD), whereas the potential mechanisms remain poorly understood. Taking advantage of chemical biology, that mitochondrial serine hydroxymethyltransferase (SHMT2) directly regulated the translation of ADAM metallopeptidase domain 10 (ADAM10), a therapeutic target for AD is reported. That the small-molecule kenpaullone (KEN) promoted ADAM10 translation via the 5' untranslated region (5'UTR) and improved cognitive functions in APP/PS1 mice is found. SHMT2, which is identified as a target gene of KEN and the 5'UTR-interacting RNA binding protein (RBP), mediated KEN-induced ADAM10 translation in vitro and in vivo. SHMT2 controls AD signaling pathways through binding to a large number of RNAs and enhances the 5'UTR activity of ADAM10 by direct interaction with GAGGG motif, whereas this motif affected ribosomal scanning of eukaryotic initiation factor 2 (eIF2) in the 5'UTR. Together, KEN exhibits therapeutic potential for AD by linking OCM with RNA processing, in which the metabolic enzyme SHMT2 "moonlighted" as RBP by binding to GAGGG motif and promoting the 5'UTR-dependent ADAM10 translation initiation.

Epigenetic Genome Modifications during Pregnancy: The Impact of Essential Nutritional Supplements on DNA Methylation

Pregnancy is an extremely stressful period in a pregnant woman's life. Currently, women's awareness of the proper course of pregnancy and its possible complications is constantly growing. Therefore, a significant percentage of women increasingly reach for various dietary supplements during gestation. Some of the most popular substances included in multi-ingredient supplements are folic acid and choline. Those substances are associated with positive effects on fetal intrauterine development and fewer possible pregnancy-associated complications. Recently, more and more attention has been paid to the impacts of specific environmental factors, such as diet, stress, physical activity, etc., on epigenetic modifications, understood as changes occurring in gene expression without the direct alteration of DNA sequences. Substances such as folic acid and choline may participate in epigenetic modifications by acting via a one-carbon cycle, leading to the methyl-group donor formation. Those nutrients may indirectly impact genome phenotype by influencing the process of DNA methylation. This review article presents the current state of knowledge on the use of folic acid and choline supplementation during pregnancy, taking into account their impacts on the maternal-fetal unit and possible pregnancy outcomes, and determining possible mechanisms of action, with particular emphasis on their possible impacts on epigenetic modifications.

O-GlcNAc signaling increases neuron regeneration through one-carbon metabolism in Caenorhabditis elegans

Cellular metabolism plays an essential role in the regrowth and regeneration of a neuron following physical injury. Yet, our knowledge of the specific metabolic pathways that are beneficial to neuron regeneration remains sparse. Previously, we have shown that modulation of O-linked β-N-acetylglucosamine (O-GlcNAc) signaling, a ubiquitous post-translational modification that acts as a cellular nutrient sensor, can significantly enhance in vivo neuron regeneration. Here, we define the specific metabolic pathway by which O-GlcNAc transferase (ogt-1) loss of function mediates increased regenerative outgrowth. Performing in vivo laser axotomy and measuring subsequent regeneration of individual neurons in C. elegans, we find that glycolysis, serine synthesis pathway (SSP), one-carbon metabolism (OCM), and the downstream transsulfuration metabolic pathway (TSP) are all essential in this process. The regenerative effects of ogt-1 mutation are abrogated by genetic and/or pharmacological disruption of OCM and the SSP linking OCM to glycolysis. Testing downstream branches of this pathway, we find that enhanced regeneration is dependent only on the vitamin B12 independent shunt pathway. These results are further supported by RNA sequencing that reveals dramatic transcriptional changes by the ogt-1 mutation, in the genes involved in glycolysis, OCM, TSP, and ATP metabolism. Strikingly, the beneficial effects of the ogt-1 mutation can be recapitulated by simple metabolic supplementation of the OCM metabolite methionine in wild-type animals. Taken together, these data unearth the metabolic pathways involved in the increased regenerative capacity of a damaged neuron in ogt-1 animals and highlight the therapeutic possibilities of OCM and its related pathways in the treatment of neuronal injury.

Folate receptor overexpression induces toxicity in a diet-dependent manner in C. elegans

Folate receptor (FR) alpha (FOLR1) and beta (FOLR2) are membrane-anchored folate transporters that are expressed at low levels in normal tissues, while their expression is strongly increased in several cancers. Intriguingly, although the function of these receptors in, for example, development and cancer has been studied intensively, their role in aging is still unknown. To address this, we utilized Caenorhabditis elegans, in which FOLR-1 is the sole ortholog of folate receptors. We found that the loss of FOLR-1 does not affect reproduction, physical condition, proteostasis or lifespan, indicating that it is not required for folate transport to maintain health. Interestingly, we found that FOLR-1 is detectably expressed only in uterine-vulval cells, and that the histone-binding protein LIN-53 inhibits its expression in other tissues. Furthermore, whereas knockdown of lin-53 is known to shorten lifespan, we found that the loss of FOLR-1 partially rescues this phenotype, suggesting that elevated folr-1 expression is detrimental for health. Indeed, our data demonstrate that overexpression of folr-1 is toxic, and that this phenotype is dependent on diet. Altogether, this work could serve as a basis for further studies to elucidate the organismal effects of abnormal FR expression in diseases such as cancer.

Exploring the complexities of 1C metabolism: implications in aging and neurodegenerative diseases

The intricate interplay of one-carbon metabolism (OCM) with various cellular processes has garnered substantial attention due to its fundamental implications in several biological processes. OCM serves as a pivotal hub for methyl group donation in vital biochemical reactions, influencing DNA methylation, protein synthesis, and redox balance. In the context of aging, OCM dysregulation can contribute to epigenetic modifications and aberrant redox states, accentuating cellular senescence and age-associated pathologies. Furthermore, OCM's intricate involvement in cancer progression is evident through its capacity to provide essential one-carbon units crucial for nucleotide synthesis and DNA methylation, thereby fueling uncontrolled cell proliferation and tumor development. In neurodegenerative disorders like Alzheimer's and Parkinson's, perturbations in OCM pathways are implicated in the dysregulation of neurotransmitter synthesis and mitochondrial dysfunction, contributing to disease pathophysiology. This review underscores the profound impact of OCM in diverse disease contexts, reinforcing the need for a comprehensive understanding of its molecular complexities to pave the way for targeted therapeutic interventions across inflammation, aging and neurodegenerative disorders.

Metabolomic Insight into Implications of Induction Chemotherapy Followed by Concomitant Chemoradiotherapy in Locally Advanced Head and Neck Cancer

The present study compares two groups of locally advanced patients with head and neck squamous cell carcinoma (LA-HNSCC) undergoing concurrent chemoradiotherapy (cCHRT), specifically those for whom it is a first-line treatment and those who have previously received induction chemotherapy (iCHT). The crucial question is whether iCHT is a serious burden during subsequent treatment for LA-HNSCC and how iCHT affects the tolerance to cCHRT. Of the 107 LA-HNSCC patients, 54 received cisplatin-based iCHT prior to cCHRT. The patients were clinically monitored at weekly intervals from the day before until the completion of the cCHRT. The 843 blood samples were collected and divided into two aliquots: for laboratory blood tests and for nuclear magnetic resonance (NMR) spectroscopy (a Bruker 400 MHz spectrometer). The NMR metabolites and the clinical parameters from the laboratory blood tests were analyzed using orthogonal partial least squares analysis (OPLS) and the Mann-Whitney U test (MWU). After iCHT, the patients begin cCHRT with significantly (MWU p-value < 0.05) elevated blood serum lipids, betaine, glycine, phosphocholine, and reticulocyte count, as well as significantly lowered NMR inflammatory markers, serine, hematocrit, neutrophile, monocyte, red blood cells, hemoglobin, and CRP. During cCHRT, a significant increase in albumin and psychological distress was observed, as well as a significant decrease in platelet, N-acetyl-cysteine, tyrosine, and phenylalanine, in patients who received iCHT. Importantly, all clinical symptoms (except the decreased platelets) and most metabolic alterations (except for betaine, serine, tyrosine, glucose, and phosphocholine) resolve until the completion of cCHRT. In conclusion, iCHT results in hematological toxicity, altered lipids, and one-carbon metabolism, as well as downregulated inflammation, as observed at the beginning and during cCHRT. However, these complications are temporary, and most of them resolve at the end of the treatment. This suggests that iCHT prior to cCHRT does not pose a significant burden and should be considered as a safe treatment option for LA-HNSCC.

Single-Cell Transcriptomics and In Vitro Lineage Tracing Reveals Differential Susceptibility of Human iPSC-Derived Midbrain Dopaminergic Neurons in a Cellular Model of Parkinson's Disease

Advances in stem cell technologies open up new avenues for modelling development and diseases. The success of these pursuits, however, relies on the use of cells most relevant to those targeted by the disease of interest, for example, midbrain dopaminergic neurons for Parkinson's disease. In the present study, we report the generation of a human induced pluripotent stem cell (iPSC) line capable of purifying and tracing nascent midbrain dopaminergic progenitors and their differentiated progeny via the expression of a Blue Fluorescent Protein (BFP). This was achieved by CRISPR/Cas9-assisted knock-in of BFP and Cre into the safe harbour locus AAVS1 and an early midbrain dopaminergic lineage marker gene LMX1A, respectively. Immunocytochemical analysis and single-cell RNA sequencing of iPSC-derived neural cultures confirm developmental recapitulation of the human fetal midbrain and high-quality midbrain cells. By modelling Parkinson's disease-related drug toxicity using 1-Methyl-4-phenylpyridinium (MPP+), we showed a preferential reduction of BFP+ cells, a finding demonstrated independently by cell death assays and single-cell transcriptomic analysis of MPP+ treated neural cultures. Together, these results highlight the importance of disease-relevant cell types in stem cell modelling.

The comprehensive mechanism underlying Schisandra polysaccharide in AD-like symptoms of Aβ25-35-induced rats based on hippocampal metabolomics and serum lipidomics techniques

As is well documented, Alzheimer's disease (AD) is the most prevalent neurodegenerative disease. Meanwhile, Schisandra polysaccharide (SCP) has been reported to exert a protective effect on the nervous system and can regulate metabolic disorders in AD-like symptoms of amyloid β-peptide (Aβ) 25-35-induced rats. Nevertheless, the underlying mechanisms and metabolic markers for the diagnosis of AD are yet to be determined. This study aimed to explore the neuroprotective effect and potential mechanism of action of SCP in AD-like symptoms of Aβ25-35-induced rats by combining pharmacodynamics, metabolomics, and lipidomics. The pharmacodynamic results revealed that SCP significantly improved the spatial learning and long-term memory function and the morphology of neurons in the hippocampal CA1 region, alleviated inflammatory damage and oxidative stress, inhibited the activation of microglia and astrocytes, and increased the proportion of mature neurons of AD-like symptoms of Aβ25-35-induced rats. The results of hippocampal metabolomics and serum lipidomics showed 46 and 48 potential biomarkers were identified for the SCP treatment of AD, respectively. The involved pathways principally comprised lipid metabolism, amino acid metabolism, and energy metabolism. This study elucidates the neuroprotective effect of SCP in AD and its mechanism from the perspective of metabolomics and lipidomics and provides a theoretical basis for the therapeutic effect of SCP in AD.

Effect of Basic Amino Acids on Folic Acid Solubility

To prevent neural tube defects and other cardiovascular diseases in newborns, folic acid (FA) is recommended in pregnant women. A daily dose of 600 µg FA consumption is widely prescribed for women during pregnancy and 400 µg for women with childbearing potential. FA is a class IV compound according to the Biopharmaceutics Classification System (BCS) due to its low permeability (1.7 × 10-6 cm/s) and low solubility (1.6 mg/L); therefore, it must be administered via a formulation that enhances its solubility. Studies reported in the literature have proved that co-amorphization and salt formation of a poorly soluble drug with amino acids (AA) can significantly increase its solubility. Although arginine has been used with FA as a supplement, there is no information on the effect of basic AA (arginine and lysine) on the physical and chemical properties of FA-AA binary formulations. The present study implemented a conductimetric titration methodology to find the effective molar ratio to maximize FA solubility. The results showed that a 1:2.5 FA:AA molar ratio maximized solubility for arginine and lysine. Binary formulations were prepared using different methods, which led to an amorphous system confirmed by the presence of a glass transition, broad FTIR bands, and the absence of an X-ray diffraction pattern. Results of FA:AA (1:2.5) solubility increased in the range of 5500-6000 times compared with pure FA. In addition to solubility enhancement, the binary systems presented morphological properties that depend on the preparation method and whose consideration could be strategic for scaling purposes.

[Nutrition and age-related macular degeneration]

Age-related macular degeneration (AMD) is the leading cause of vision loss in France and in other industrialized countries. AMD affects around 20 % of the population over the age of 80 years. This complex and multifactorial disease involves both genetic susceptibility and environmental factors. Smoking and nutrition are well-known modifiable risk factors for AMD. Numerous studies provide convincing arguments in favor of micronutrients to encourage dietary advice and the prescription of nutritional supplements containing antioxidant vitamins, lutein and omega-3 fatty acids. Attention to modifiable risk factors is of utmost importance to reduce progression to advanced AMD and associated medical and societal burdens.

Shared metabolic shifts in endothelial cells in stroke and Alzheimer's disease revealed by integrated analysis

Since metabolic dysregulation is a hallmark of both stroke and Alzheimer's disease (AD), mining shared metabolic patterns in these diseases will help to identify their possible pathogenic mechanisms and potential intervention targets. However, a systematic integration analysis of the metabolic networks of the these diseases is still lacking. In this study, we integrated single-cell RNA sequencing datasets of ischemic stroke (IS), hemorrhagic stroke (HS) and AD models to construct metabolic flux profiles at the single-cell level. We discovered that the three disorders cause shared metabolic shifts in endothelial cells. These altered metabolic modules were mainly enriched in the transporter-related pathways and were predicted to potentially lead to a decrease in metabolites such as pyruvate and fumarate. We further found that Lef1, Elk3 and Fosl1 may be upstream transcriptional regulators causing metabolic shifts and may be possible targets for interventions that halt the course of neurodegeneration.

Plasma metabolomics of oral squamous cell carcinomas based on NMR and MS approaches provides biomarker identification and survival prediction

Metabolomics has proven to be an important omics approach to understand the molecular pathways underlying the tumour phenotype and to identify new clinically useful markers. The literature on cancer has illustrated the potential of this approach as a diagnostic and prognostic tool. The present study aimed to analyse the plasma metabolic profile of patients with oral squamous cell carcinoma (OSCC) and controls and to compare patients with metastatic and primary tumours at different stages and subsites using nuclear magnetic resonance and mass spectrometry. To our knowledge, this is the only report that compared patients at different stages and subsites and replicates collected in diverse institutions at different times using these methodologies. Our results showed a plasma metabolic OSCC profile suggestive of abnormal ketogenesis, lipogenesis and energy metabolism, which is already present in early phases but is more evident in advanced stages of the disease. Reduced levels of several metabolites were also associated with an unfavorable prognosis. The observed metabolomic alterations may contribute to inflammation, immune response inhibition and tumour growth, and may be explained by four nonexclusive views-differential synthesis, uptake, release, and degradation of metabolites. The interpretation that assimilates these views is the cross talk between neoplastic and normal cells in the tumour microenvironment or in more distant anatomical sites, connected by biofluids, signalling molecules and vesicles. Additional population samples to evaluate the details of these molecular processes may lead to the discovery of new biomarkers and novel strategies for OSCC prevention and treatment.

Pathological characteristics of axons and proteome patterns in midbrain dopaminergic neurodegeneration induced by WDR45-deficiency

Background

Although WD repeats domain 45 (WDR45) mutations have been linked to β-propeller protein-associated neurodegeneration (BPAN), the precise molecular and cellular mechanisms behind this disease remain elusive. This study aims to shed light on the effects of WDR45-deficiency on neurodegeneration, specifically axonal degeneration, within the midbrain dopaminergic (DAergic) system. By examining pathological and molecular alterations, we hope to better understand the disease process.

Methods

To investigate the effects of WDR45 dysfunction on mouse behaviors and DAergic neurons, we developed a mouse model in which WDR45 was conditionally knocked out in midbrain DAergic neurons (WDR45cKO). Through a longitudinal study, we assessed alterations in mouse behavior using open field, rotarod, Y-maze, and 3-chamber social approach tests. To examine the pathological changes in DAergic neuron soma and axons, we utilized a combination of immunofluorescence staining and transmission electron microscopy. Additionally, we performed proteomic analyses of the striatum to identify the molecules and processes involved in striatal pathology.

Results

Our study of WDR45cKO mice revealed a range of deficits, including impaired motor function, emotional instability, and memory loss, coinciding with the profound loss of midbrain DAergic neurons. Prior to neuronal loss, we observed massive axonal enlargements in both the dorsal and ventral striatum. These enlargements were characterized by the accumulation of extensively fragmented tubular endoplasmic reticulum (ER), a hallmark of axonal degeneration. Additionally, we found that WDR45cKO mice exhibited disrupted autophagic flux. Proteomic analysis of the striatum in these mice showed that many differentially expressed proteins (DEPs) were enriched in amino acid, lipid, and tricarboxylic acid metabolisms. Of note, we observed significant alterations in the expression of genes encoding DEPs that regulate phospholipids catabolic and biosynthetic processes, such as lysophosphatidylcholine acyltransferase 1, ethanolamine-phosphate phospho-lyase, and abhydrolase domain containing 4, N-acyl phospholipase B. These findings suggest a possible link between phospholipid metabolism and striatal axon degeneration.

Conclusions

In this study, we have uncovered the molecular mechanisms underlying the contribution of WDR45-deficiency to axonal degeneration, revealing intricate relationships between tubular ER dysfunction, phospholipid metabolism, BPAN and other neurodegenerative diseases. These findings significantly advance our understanding of the fundamental molecular mechanisms driving neurodegeneration and may provide a foundation for developing novel, mechanistically-based therapeutic interventions.

Mapping the metabolic reprogramming induced by sodium-glucose cotransporter 2 inhibition

Diabetes is associated with increased risk for kidney disease, heart failure, and mortality. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) prevent these adverse outcomes; however, the mechanisms involved are not clear. We generated a roadmap of the metabolic alterations that occur in different organs in diabetes and in response to SGLT2i. In vivo metabolic labeling with 13C-glucose in normoglycemic and diabetic mice treated with or without dapagliflozin, followed by metabolomics and metabolic flux analyses, showed that, in diabetes, glycolysis and glucose oxidation are impaired in the kidney, liver, and heart. Treatment with dapagliflozin failed to rescue glycolysis. SGLT2 inhibition increased glucose oxidation in all organs; in the kidney, this was associated with modulation of the redox state. Diabetes was associated with altered methionine cycle metabolism, evident by decreased betaine and methionine levels, whereas treatment with SGLT2i increased hepatic betaine along with decreased homocysteine levels. mTORC1 activity was inhibited by SGLT2i along with stimulation of AMPK in both normoglycemic and diabetic animals, possibly explaining the protective effects against kidney, liver, and heart diseases. Collectively, our findings suggest that SGLT2i induces metabolic reprogramming orchestrated by AMPK-mTORC1 signaling with common and distinct effects in various tissues, with implications for diabetes and aging.

Network-level analysis of ageing and its relationship with diseases and tissue regeneration in the mouse liver

The liver plays a vital role in maintaining whole-body metabolic homeostasis, compound detoxification and has the unique ability to regenerate itself post-injury. Ageing leads to functional impairment of the liver and predisposes the liver to non-alcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC). Mapping the molecular changes of the liver with ageing may help to understand the crosstalk of ageing with different liver diseases. A systems-level analysis of the ageing-induced liver changes and its crosstalk with liver-associated conditions is lacking. In the present study, we performed network-level analyses of the ageing liver using mouse transcriptomic data and a protein-protein interaction (PPI) network. A sample-wise analysis using network entropy measure was performed, which showed an increasing trend with ageing and helped to identify ageing genes based on local entropy changes. To gain further insights, we also integrated the differentially expressed genes (DEGs) between young and different age groups with the PPI network and identified core modules and nodes associated with ageing. Finally, we computed the network proximity of the ageing network with different networks of liver diseases and regeneration to quantify the effect of ageing. Our analysis revealed the complex interplay of immune, cancer signalling, and metabolic genes in the ageing liver. We found significant network proximities between ageing and NAFLD, HCC, liver damage conditions, and the early phase of liver regeneration with common nodes including NLRP12, TRP53, GSK3B, CTNNB1, MAT1 and FASN. Overall, our study maps the network-level changes of ageing and their interconnections with the physiology and pathology of the liver.

One-carbon metabolic enzymes are regulated during cell division and make distinct contributions to the metabolome and cell cycle progression in Saccharomyces cerevisiae

Enzymes of one-carbon (1C) metabolism play pivotal roles in proliferating cells. They are involved in the metabolism of amino acids, nucleotides, and lipids and the supply of all cellular methylations. However, there is limited information about how these enzymes are regulated during cell division and how cell cycle kinetics are affected in several loss-of-function mutants of 1C metabolism. Here, we report that the levels of the S. cerevisiae enzymes Ade17p and Cho2p, involved in the de novo synthesis of purines and phosphatidylcholine (PC), respectively, are cell cycle-regulated. Cells lacking Ade17p, Cho2p, or Shm2p (an enzyme that supplies 1C units from serine) have distinct alterations in size homeostasis and cell cycle kinetics. Loss of Ade17p leads to a specific delay at START, when cells commit to a new round of cell division, while loss of Shm2p has broader effects, reducing growth rate. Furthermore, the inability to synthesize PC de novo in cho2Δ cells delays START and reduces the coherence of nuclear elongation late in the cell cycle. Loss of Cho2p also leads to profound metabolite changes. Besides the expected changes in the lipidome, cho2Δ cells have reduced levels of amino acids, resembling cells shifted to poorer media. These results reveal the different ways that 1C metabolism allocates resources to affect cell proliferation at multiple cell cycle transitions.

The role of maternal choline, folate and one-carbon metabolism in mediating the impact of prenatal alcohol exposure on placental and fetal development

Prenatal alcohol consumption (PAE) may be associated with a broad spectrum of impacts, ranging from no overt effects, to miscarriage, fetal growth restriction and fetal alcohol spectrum disorder. A major mechanism underlying the effects of PAE is considered to be altered DNA methylation and gene expression. Maternal nutritional status may be an important factor in determining the extent to which PAE impacts pregnancy outcomes, particularly the dietary micronutrients folate and choline because they provide methyl groups for DNA methylation via one carbon metabolism. This review summarises the roles of folate and choline in development of the blastocyst, the placenta and the fetal brain, and examines the evidence that maternal intake of these micronutrients can modify the effects of PAE on development. Studies of folate or choline deficiency have found reduced blastocyst development and implantation, reduced placental invasion, vascularisation and nutrient transport capability, impaired fetal brain development, and abnormal neurodevelopmental outcomes. PAE has been shown to reduce absorption and/or metabolism of folate and choline and to produce similar outcomes to maternal choline/folate deficiency. A few studies have demonstrated that the effects of PAE on brain development can be ameliorated by folate or choline supplementation; however, there is very limited evidence on the effects of supplementation in early pregnancy on the blastocyst and placenta. Further studies are required to support these findings and to determine optimal supplementation parameters.

Mitochondrial protein import machinery conveys stress signals to the cytosol and beyond

Mitochondria hold diverse and pivotal roles in fundamental processes that govern cell survival, differentiation, and death, in addition to organismal growth, maintenance, and aging. The mitochondrial protein import system is a major contributor to mitochondrial biogenesis and lies at the crossroads between mitochondrial and cellular homeostasis. Recent findings highlight the mitochondrial protein import system as a signaling hub, receiving inputs from other cellular compartments and adjusting its function accordingly. Impairment of protein import, in a physiological, or disease context, elicits adaptive responses inside and outside mitochondria. In this review, we discuss recent developments, relevant to the mechanisms of mitochondrial protein import regulation, with a particular focus on quality control, proteostatic and metabolic cellular responses, triggered upon impairment of mitochondrial protein import.

Role of Mitochondria in Environmentally and Dietary Modulated Age-Associated Diseases

Aging is an intricate and unavoidable phenomenon characterized by progressive accumulation of damage to cellular structural components with consequent decline in physiological functions and development of different pathological conditions, which lead to increase in frailty and mortality risk and bring a huge economic burden in our society [...].

Tracing the electron flow in redox metabolism: The appropriate distribution of electrons is essential to maintain redox balance in cancer cells

Cancer cells are characterized by sustained proliferation, which requires a huge demand of fuels to support energy production and biosynthesis. Energy is produced by the oxidation of the fuels during catabolism, and biosynthesis is achieved by the reduction of smaller units or precursors. Therefore, the oxidation-reduction (redox) reactions in cancer cells are more active compared to those in the normal counterparts. The higher activity of redox metabolism also induces a more severe oxidative stress, raising the question of how cancer cells maintain the redox balance. In this review, we overview the redox metabolism of cancer cells in an electron-tracing view. The electrons are derived from the nutrients in the tumor microenvironment and released during catabolism. Most of the electrons are transferred to NAD(P) system and then directed to four destinations: energy production, ROS generation, reductive biosynthesis and antioxidant system. The appropriate distribution of these electrons achieved by the function of redox regulation network is essential to maintain redox homeostasis in cancer cells. Interfering with the electron distribution and disrupting redox balance by targeting the redox regulation network may provide therapeutic implications for cancer treatment.

Characteristics of gut microbiota and fecal metabolomes in patients with celiac disease in Northwest China

Celiac disease (CD) is an autoimmune small bowel disease. The pattern of gut microbiota is closely related to dietary habits, genetic background, and geographical factors. There is a lack of research on CD-related gut microbiota in China. This study aimed to use 16S rDNA sequencing and metabolomics to analyze the fecal microbial composition and metabolome characteristics in patients diagnosed with CD in Northwest China, and to screen potential biomarkers that could be used for its diagnosis. A significant difference in the gut microbiota composition was observed between the CD and healthy controls groups. At the genus level, the abundance of Streptococcus, Lactobacillus, Veillonella, and Allisonella communities in the CD group were increased (Q < 0.05). Furthermore, the abundance of Ruminococcus, Faecalibacterium, Blautia, Gemmiger, and Anaerostipes community in this group were decreased (Q < 0.05). A total of 222 different fecal metabolites were identified in the two groups, suggesting that CD patients have a one-carbon metabolism defect. Four species of bacteria and six metabolites were selected as potential biomarkers using a random forest model. Correlation analysis showed that changes in the gut microbiota were significantly correlated with changes in fecal metabolite levels. In conclusion, the patterns of distribution of gut microbiota and metabolomics in patients with CD in Northwest China were found to be unique to these individuals. This has opened up a new way to explore potential beneficial effects of supplementing specific nutrients and potential diagnostic and therapeutic targets in the future.

B Vitamins and Incidence of Advanced Age-Related Macular Degeneration: The Alienor Study

B vitamins may protect against age-related macular degeneration (AMD). We evaluated the associations of dietary intake and serum vitamins with the incidence of advanced AMD in the Alienor study. The Alienor study is a prospective population-based cohort of 963 residents of Bordeaux, France, who were 73 years or older at baseline (2006-2008). Examinations were performed every two years over an eight-year period. The incidence of AMD is based on retinal fundus photographs and spectral-domain optical coherence tomography examinations. Among the 861 included participants, 93 developed incident AMD during a median follow-up time of 9.8 years. Participants with normal serum folate (≥10 nmol/L) significantly had a 51% reduced risk for AMD in the fully adjusted Cox model (HR, 0.49 [95% CI, 0.25-0.95], p = 0.036). Participants with a higher dietary intake of B5 and B6 vitamins had a lower risk for developing AMD of up to 28% (HR, 0.72 for 1-SD increase [0.53-0.99], p = 0.049; HR, 0.90 [0.81-0.99], p = 0.049, respectively). This cohort study of older adults suggests a strong association between a normal serum folate status, a high dietary intake of B5 and B6 and a lower risk for developing advanced AMD. Adopting a healthy diet rich in B vitamins may help to reduce vision loss due to AMD.

Prenatal Choline Supplementation Alters One Carbon Metabolites in a Rat Model of Periconceptional Alcohol Exposure

Prenatal alcohol exposure disturbs fetal and placental growth and can alter DNA methylation (DNAm). Supplementation with the methyl donor choline can increase fetal and placental growth and restore DNAm, suggesting converging effects on one-carbon metabolism (1CM). We investigated the impact of periconceptional ethanol (PCE) exposure and prenatal choline supplementation on 1CM in maternal, placental, and fetal compartments. Female Sprague Dawley rats were given a liquid diet containing 12.5% ethanol (PCE) or 0% ethanol (control) for 4 days before and 4 days after conception. Dams were then placed on chow with different concentrations of choline (1.6 g, 2.6 g, or 7.2 g choline/kg chow). Plasma and tissues were collected in late gestation for the analysis of 1CM components by means of mass spectrometry and real-time PCR. PCE reduced placental components of 1CM, particularly those relating to folate metabolism, resulting in a 3−7.5-fold reduction in the ratio of s-adenosylmethionine:s-adenosylhomocysteine (SAM:SAH) (p < 0.0001). Choline supplementation increased placental 1CM components and the SAM:SAH ratio (3.5−14.5-fold, p < 0.0001). In the maternal and fetal compartments, PCE had little effect, whereas choline increased components of 1CM. This suggests that PCE impairs fetal development via altered placental 1CM, highlighting its role in modulating nutritional inputs to optimize fetal development.