Vitamin B12 coordinates ileal epithelial cell and microbiota functions to resist Salmonella infection in mice

Comparative Gene Expression Analysis of Salmonella Typhimurium DT104 in Ground Chicken Extract and Brain Heart Infusion Broth

Salmonella enterica Typhimurium DT104 (S. Typhimurium DT104) is an important foodborne pathogen that is associated with poultry and poultry products. Currently, there is very little information on the underlying molecular mechanisms that allow DT104 to survive and propagate in poultry meat and the poultry processing environment. The current study assessed the global gene expression of DT104 in ground chicken extract (GCE) compared to brain heart infusion (BHI) medium using RNA-Seq technology. DT104 was grown to the early stationary phase (ESP), inoculated into GCE or BHI, and then re-grown to the log phase before RNA was extracted and transcripts were quantified by RNA-Seq. Gene expression for DT104 grown in GCE was then compared to that of DT104 grown in BHI for samples grown to the ESP. Growth in GCE resulted in the up-regulated expression of genes related to translation, carnitine metabolism (23-283-fold change), and cobalamin (vitamin B12) biosynthesis (14-fold change). In particular, the presence of carnitine in chicken meat, and thus, in GCE, which lacks carbohydrates, may allow Salmonella to utilize this compound as a carbon and nitrogen source. This study demonstrates that RNA-Seq data can provide a comprehensive analysis of DT104 gene expression in a food model for poultry products. This study also provides additional evidence for the importance of metabolic adaptation in the ability of S. enterica to successfully adapt to and occupy niches outside of its host and provides potential targets that could be used to develop intervention strategies to control Salmonella in poultry.

Implications of hypocobalaminemia as a negative prognostic marker in juvenile dogs with parvovirus enteritis

Introduction

Canine Parvovirus 2 (CPV-2) infection poses a significant global health risk to susceptible dogs. Hypocobalaminemia, defined as reduced serum cobalamin (CBL) concentrations, is a recognized complication in chronic enteropathies in adult dogs but remains poorly understood in the context of acute enteropathies, especially in young dogs. The aim of this study was to investigate the frequency and severity of hypocobalaminemia in young dogs with parvovirus enteritis and evaluation of CBL as a predictor of outcome.

Materials and methods

Thirty client-owned dogs diagnosed with parvovirus infection and thirty healthy controls were enrolled. Clinical, hematological, and biochemical tests, including CBL and serum methylmalonic acid (MMA) concentrations, were assessed.

Results

Results indicated a significantly higher prevalence of hypocobalaminemia in dogs with parvovirus enteritis compared to healthy controls, as well as a significant correlation with a disease severity score. Moreover, survivors demonstrated higher CBL concentrations than non-survivors, suggesting an eventual prognostic value of CBL status. However, parenteral CBL supplementation showed no significant effect on serum CBL or MMA concentrations, highlighting potential challenges in CBL uptake at the cellular level.

Discussion

Hypocobalaminemia in this population is caused by multiple factors such as reduced nutritional absorption, gastrointestinal losses, and increased metabolic demands. Further research is needed to develop tailored management strategies, evaluate the effectiveness of CBL supplementation, and understand the mechanisms behind hypocobalaminemia in parvovirus infection.

Vitamin-mediated interaction between the gut microbiome and mitochondria in depression: A systematic review-based integrated perspective

Depression is one of the world's most prevalent mental disorders and its treatment remains suboptimal. Depression is a systemic disease with highly complex biological mechanisms. Emerging evidence points towards the involvement of mitochondria, microbiome and vitamins in its pathophysiology. Mitochondrial energy production was shown to be lowered in patients with depression. Mitochondrial energy production depends on vitamins, which are available from food, but are also synthesized by the gut microbiota. Several studies reported altered vitamin levels as well as changes in the gut microbiome composition and its vitamin metabolism in patients with depression. Therefore, the question of a connection between mitochondria and gut microbiome and vitamins influencing the mental health arises. This review aims to systematically investigate a combination of the topics - depression, mitochondria, microbiome, and vitamins - to generate an overview of a novel yet extremely complex and interconnected research field. A systematic literature search yielded 34 articles, and the results were summarized and bundled to develop this new integrative perspective on mitochondrial function mediated by the microbiome and microbiome-derived vitamins in depression. Furthermore, by discussing the research gaps this review aims to encourage innovative research approaches to better understand the biology of depression, which could result in optimized therapeutic approaches.

A Direct Link Implicating Loss of SLC26A6 to Gut Microbial Dysbiosis, Compromised Barrier Integrity, and Inflammation

BACKGROUND & AIMS

Putative anion transporter-1 (PAT1, SLC26A6) plays a key role in intestinal oxalate and bicarbonate secretion. PAT1 knockout (PKO) mice exhibit hyperoxaluria and nephrolithiasis. Notably, diseases such as inflammatory bowel disease are also associated with higher risk of hyperoxaluria and nephrolithiasis. However, the potential role of PAT1 deficiency in gut-barrier integrity and susceptibility to colitis is currently elusive.

METHODS

Age-matched PKO and wild-type littermates were administered 3.5% dextran sulfate sodium in drinking water for 6 days. Ileum and colon of control and treated mice were harvested. Messenger RNA and protein expression of tight junction proteins were determined by reverse transcription polymerase chain reaction and western blotting. Severity of inflammation was assessed by measuring diarrheal phenotype, cytokine expression, and hematoxylin and eosin staining. Gut microbiome and associated metabolome were analyzed by 16S ribosomal RNA sequencing and mass spectrometry, respectively.

RESULTS

PKO mice exhibited significantly higher loss of body weight, gut permeability, colonic inflammation, and diarrhea in response to dextran sulfate sodium treatment. In addition, PKO mice showed microbial dysbiosis and significantly reduced levels of butyrate and butyrate-producing microbes compared with controls. Co-housing wild-type and PKO mice for 4 weeks resulted in PKO-like signatures on the expression of tight junction proteins in the colons of wild-type mice.

CONCLUSIONS

Our data demonstrate that loss of PAT1 disrupts gut microbiome and related metabolites, decreases gut-barrier integrity, and increases host susceptibility to intestinal inflammation. These findings, thus, highlight a novel role of the oxalate transporter PAT1 in promoting gut-barrier integrity, and its deficiency appears to contribute to the pathogenesis of inflammatory bowel diseases.

Functional regulation of microglia by vitamin B12 alleviates ischemic stroke-induced neuroinflammation in mice

Ischemic stroke is the second leading cause of death and disability worldwide, and efforts to prevent stroke, mitigate secondary neurological damage, and promote neurological recovery remain paramount. Recent findings highlight the critical importance of microbiome-related metabolites, including vitamin B12 (VB12), in alleviating toxic stroke-associated neuroinflammation. Here, we showed that VB12 tonically programmed genes supporting microglial cell division and activation and critically controlled cellular fatty acid metabolism in homeostasis. Intriguingly, VB12 promoted mitochondrial transcriptional and metabolic activities and significantly restricted stroke-associated gene alterations in microglia. Furthermore, VB12 differentially altered the functions of microglial subsets during the acute phase of ischemic stroke, resulting in reduced brain damage and improved neurological function. Pharmacological depletion of microglia before ischemic stroke abolished VB12-mediated neurological improvement. Thus, our preclinical studies highlight the relevance of VB12 in the functional programming of microglia to alleviate neuroinflammation, minimize ischemic injury, and improve host neurological recovery after ischemic stroke.

Gestational Diabetes Mellitus: What Can Medical Nutrition Therapy Do?

Gestational diabetes mellitus (GDM) is one of the common complications during pregnancy. Numerous studies have shown that GDM is associated with a series of adverse effects on both mothers and offspring. Due to the particularity of pregnancy, medical nutrition treatment is considered to be the first choice for the treatment of GDM. This contribution reviews the research progress of medical nutrition treatment in GDM, summarizes the international recommendations on the intake of various nutrients and the influence of nutrients on the prevalence of GDM, and the improvement effect of nutritional intervention on it, in order to provide references for research in related fields of GDM and the targeted development of enteral nutrition.

Lupus susceptibility gene Pbx1 controls the development, stability, and function of regulatory T cells via Rtkn2 expression

The maintenance of regulatory T (Treg) cells critically prevents autoimmunity. Pre-B cell leukemia transcription factor 1 (Pbx1) variants are associated with lupus susceptibility, particularly through the expression of a dominant negative isoform Pbx1-d in CD4+ T cells. Pbx1-d overexpression impaired Treg cell homeostasis and promoted inflammatory CD4+ T cells. Here, we showed a high expression of Pbx1 in human and murine Treg cells, which is decreased in lupus patients and mice. Pbx1 deficiency or Pbx1-d overexpression reduced the number, stability, and suppressive activity of Treg cells, which increased murine responses to immunization and autoimmune induction. Mechanistically, Pbx1 deficiency altered the expression of genes implicated in cell cycle and apoptosis in Treg cells. Intriguingly, Rtkn2, a Rho-GTPase previously associated with Treg homeostasis, was directly transactivated by Pbx1. Our results suggest that the maintenance of Treg cell homeostasis and stability by Pbx1 through cell cycle progression prevent the expansion of inflammatory T cells that otherwise exacerbates lupus progression in the hosts.

Small intestinal microbiota: from taxonomic composition to metabolism

The small intestinal microbiota (SIM) is essential for gastrointestinal health, influencing digestion, immune modulation, and nutrient metabolism. Unlike the colonic microbiota, the SIM has been poorly characterized due to sampling challenges and ethical considerations. Current evidence suggests that the SIM consists of five core genera and additional segment-specific taxa. These bacteria closely interact with the human host, regulating nutrient absorption and metabolism. Recent work suggests the presence of two forms of small intestinal bacterial overgrowth, one dominated by oral bacteria (SIOBO) and a second dominated by coliform bacteria. Less invasive sampling techniques, omics approaches, and mechanistic studies will allow a more comprehensive understanding of the SIM, paving the way for interventions engineering the SIM towards better health.

Dependency on host vitamin B12 has shaped Mycobacterium tuberculosis Complex evolution

Human and animal tuberculosis is caused by the Mycobacterium tuberculosis Complex (MTBC), which has evolved a genomic decay of cobalamin (vitamin B12) biosynthetic genes. Accordingly, and in sharp contrast to environmental, opportunistic and ancestor mycobacteria; we demonstrate that M. tuberculosis (Mtb), M. africanum, and animal-adapted lineages, lack endogenous production of cobalamin, yet they retain the capacity for exogenous uptake. A B12 anemic model in immunocompromised and immunocompetent mice, demonstrates improved survival, and lower bacteria in organs, in B12 anemic animals infected with Mtb relative to non-anemic controls. Conversely, no differences were observed between mice groups infected with M. canettii, an ancestor mycobacterium which retains cobalamin biosynthesis. Interrogation of the B12 transcriptome in three MTBC strains defined L-methionine synthesis by metE and metH genes as a key phenotype. Expression of metE is repressed by a cobalamin riboswitch, while MetH requires the cobalamin cofactor. Thus, deletion of metE predominantly attenuates Mtb in anemic mice; although inactivation of metH exclusively causes attenuation in non-anemic controls. Here, we show how sub-physiological levels of B12 in the host antagonizes Mtb virulence, and describe a yet unknown mechanism of host-pathogen cross-talk with implications for B12 anemic populations.

Interdental oral hygiene interventions elicit varying compositional microbiome changes in naturally occurring gingivitis: Secondary data analysis from a clinical trial

AIM

To evaluate the effect of different oral irrigators on the sub-gingival microbiome composition in patients with naturally occurring plaque-induced gingivitis.

MATERIALS AND METHODS

Sub-gingival plaque was collected from adults participating in a clinical trial assessing the efficacy of oral hygiene with two different oral irrigators (Waterpik Water Flosser [Group 1] and Oral-B Water Flosser [Group 2]) versus dental flossing (Group 3) for microbiome analysis. Plaque samples were reflective of naturally occurring plaque-induced gingivitis at baseline and of gingival health at the endpoint (4 weeks). Clinical measures of gingival inflammation were collected, and the sub-gingival microbiome was analysed by 16S rRNA sequencing to identify amplicon sequence variants.

RESULTS

Oral hygiene instruction with self-performed manual toothbrushing and water-jet irrigation led to significant reductions in inflammation for all groups; both oral irrigators outperformed flossing in bleeding-on-probing reduction (p < .001). Microbiome diversity of sub-gingival plaque remained relatively stable over time, but significant changes were noted in certain taxa, consistent with increases in the relative abundance of commensals and reductions in late colonizers and periodontal pathogens in the water-jet groups.

CONCLUSIONS

Reduction in gingival inflammation at 4 weeks within the water-jet groups is accompanied by slight but critical changes in microbiome composition. Although biodiversity does not substantially change within 4 weeks during the resolution of naturally induced gingivitis, significant relative increases in commensal early colonizers such as Streptococcus, Veillonella and Fusobacterium were accompanied by a shift towards a less anaerobic microbiota associated with return to health. These changes were contingent upon the type of interdental hygiene, with Group 1 exhibiting more significant alterations in microbiome composition towards a periodontal-health-compatible community.

Dietary tryptophan and genetic susceptibility expand gut microbiota that promote systemic autoimmune activation

Tryptophan modulates disease activity and the composition of microbiota in the B6.Sle1.Sle2.Sle3 (TC) mouse model of lupus. To directly test the effect of tryptophan on the gut microbiome, we transplanted fecal samples from TC and B6 control mice into germ-free or antibiotic-treated non-autoimmune B6 mice that were fed with a high or low tryptophan diet. The recipient mice with TC microbiota and high tryptophan diet had higher levels of immune activation, autoantibody production and intestinal inflammation. A bloom of Ruminococcus gnavus (Rg), a bacterium associated with disease flares in lupus patients, only emerged in the recipients of TC microbiota fed with high tryptophan. Rg depletion in TC mice decreased autoantibody production and increased the frequency of regulatory T cells. Conversely, TC mice colonized with Rg showed higher autoimmune activation. Overall, these results suggest that the interplay of genetic and tryptophan can influence the pathogenesis of lupus through the gut microbiota.

Vitamin B12 Deficiency and the Nervous System: Beyond Metabolic Decompensation-Comparing Biological Models and Gaining New Insights into Molecular and Cellular Mechanisms

Vitamin B12 (VitB12) is a micronutrient and acts as a cofactor for fundamental biochemical reactions: the synthesis of succinyl-CoA from methylmalonyl-CoA and biotin, and the synthesis of methionine from folic acid and homocysteine. VitB12 deficiency can determine a wide range of diseases, including nervous system impairments. Although clinical evidence shows a direct role of VitB12 in neuronal homeostasis, the molecular mechanisms are yet to be characterized in depth. Earlier investigations focused on exploring the biochemical shifts resulting from a deficiency in the function of VitB12 as a coenzyme, while more recent studies propose a broader mechanism, encompassing changes at the molecular/cellular levels. Here, we explore existing study models employed to investigate the role of VitB12 in the nervous system, including the challenges inherent in replicating deficiency/supplementation in experimental settings. Moreover, we discuss the potential biochemical alterations and ensuing mechanisms that might be modified at the molecular/cellular level (such as epigenetic modifications or changes in lysosomal activity). We also address the role of VitB12 deficiency in initiating processes that contribute to nervous system deterioration, including ROS accumulation, inflammation, and demyelination. Consequently, a complex biological landscape emerges, requiring further investigative efforts to grasp the intricacies involved and identify potential therapeutic targets.

Predicting Personalized Diets Based on Microbial Characteristics between Patients with Superficial Gastritis and Atrophic Gastritis

BACKGROUND

gastritis is a common stomach disease with a high global incidence and can potentially develop into gastric cancer. The treatment of gastritis focuses on medication or diets based on national guidelines. However, the specific diet that can alleviate gastritis remains largely unknown.

METHODS

we propose a microbiota-directed dietary strategy that investigates potential food factors using microbial exogenous metabolites. Given the current lack of understanding of the repeatable characteristics of gastric microbiota, we conducted a meta-analysis to identify the features of gastric bacteria. Local samples were collected as validation cohorts. Furthermore, RevEcoR was employed to identify bacteria's exogenous metabolites, and FooDB was used to retrieve foods that can target specific bacteria.

RESULTS

Bacteroides, Weissella, Actinomyces, Atopobium, Oribacterium, Peptostreptococcus, and Rothia were biomarkers between superficial gastritis (SG) and atrophic gastritis (AG) (AG_N) without H. pylori infection, whereas Bacillus, Actinomyces, Cutibacterium, Helicobacter, Novosphingobium, Pseudomonas, and Streptococcus were signatures between SG and AG (AG_P) with H. pylori infection. According to the exogenous metabolites, adenosyloobalamin, soybean, common wheat, dates, and barley were regarded as potential candidates for AG_N treatment, while gallate was regarded as a candidate for AG_P treatment.

CONCLUSIONS

this study firstly profiled the gastric microbiota of AG and SG with or without H. pylori and provided a recommended diet for global AG according to exogenous metabolites.

Receptor-interacting protein kinase 2 (RIPK2) profoundly contributes to post-stroke neuroinflammation and behavioral deficits with microglia as unique perpetrators

BACKGROUND

Receptor-interacting protein kinase 2 (RIPK2) is a serine/threonine kinase whose activity propagates inflammatory signaling through its association with pattern recognition receptors (PRRs) and subsequent TAK1, NF-κB, and MAPK pathway activation. After stroke, dead and dying cells release a host of damage-associated molecular patterns (DAMPs) that activate PRRs and initiate a robust inflammatory response. We hypothesize that RIPK2 plays a damaging role in the progression of stroke injury by enhancing the neuroinflammatory response to stroke and that global genetic deletion or microglia-specific conditional deletion of Ripk2 will be protective following ischemic stroke.

METHODS

Adult (3-6 months) male mice were subjected to 45 min of transient middle cerebral artery occlusion (tMCAO) followed by 24 h, 48 h, or 28 days of reperfusion. Aged male and female mice (18-24 months) were subjected to permanent ischemic stroke and sacrificed 48 h later. Infarct volumes were calculated using TTC staining (24-48 h) or Cresyl violet staining (28d). Sensorimotor tests (weight grip, vertical grid, and open field) were performed at indicated timepoints. Blood-brain barrier (BBB) damage, tight junction proteins, matrix metalloproteinase-9 (MMP-9), and neuroinflammatory markers were assessed via immunoblotting, ELISA, immunohistochemistry, and RT-qPCR. Differential gene expression profiles were generated through bulk RNA sequencing and nanoString®.

RESULTS

Global genetic deletion of Ripk2 resulted in decreased infarct sizes and reduced neuroinflammatory markers 24 h after stroke compared to wild-type controls. Ripk2 global deletion also improved both acute and long-term behavioral outcomes with powerful effects on reducing infarct volume and mortality at 28d post-stroke. Conditional deletion of microglial Ripk2 (mKO) partially recapitulated our results in global Ripk2 deficient mice, showing reductive effects on infarct volume and improved behavioral outcomes within 48 h of injury. Finally, bulk transcriptomic profiling and nanoString data demonstrated that Ripk2 deficiency in microglia decreases genes associated with MAPK and NF-κB signaling, dampening the neuroinflammatory response after stroke injury by reducing immune cell activation and peripheral immune cell invasion.

CONCLUSIONS

These results reveal a hitherto unknown role for RIPK2 in the pathogenesis of ischemic stroke injury, with microglia playing a distinct role. This study identifies RIPK2 as a potent propagator of neuroinflammatory signaling, highlighting its potential as a therapeutic target for post-stroke intervention.

Pharmacologic inhibition of glycolysis prevents the development of lupus by altering the gut microbiome in mice

Gut dysbiosis has been associated with lupus pathogenesis, and fecal microbiota transfers (FMT) from lupus-prone mice shown to induce autoimmune activation into healthy mice. The immune cells of lupus patients exhibit an increased glucose metabolism and treatments with 2-deoxy-D-glucose (2DG), a glycolysis inhibitor, are therapeutic in lupus-prone mice. Here, we showed in two models of lupus with different etiologies that 2DG altered the composition of the fecal microbiome and associated metabolites. In both models, FMT from 2DG-treated mice protected lupus-prone mice of the same strain from the development of glomerulonephritis, reduced autoantibody production as well as the activation of CD4+ T cells and myeloid cells as compared to FMT from control mice. Thus, we demonstrated that the protective effect of glucose inhibition in lupus is transferable through the gut microbiota, directly linking alterations in immunometabolism to gut dysbiosis in the hosts.

Metabolite interactions between host and microbiota during health and disease: Which feeds the other?

Metabolites produced by the host and microbiota play a crucial role in how human bodies develop and remain healthy. Most of these metabolites are produced by microbiota and hosts in the digestive tract. Metabolites in the gut have important roles in energy metabolism, cellular communication, and host immunity, among other physiological activities. Although numerous host metabolites, such as free fatty acids, amino acids, and vitamins, are found in the intestine, metabolites generated by gut microbiota are equally vital for intestinal homeostasis. Furthermore, microbiota in the gut is the sole source of some metabolites, including short-chain fatty acids (SCFAs). Metabolites produced by microbiota, such as neurotransmitters and hormones, may modulate and significantly affect host metabolism. The gut microbiota is becoming recognized as a second endocrine system. A variety of chronic inflammatory disorders have been linked to aberrant host-microbiota interplays, but the precise mechanisms underpinning these disturbances and how they might lead to diseases remain to be fully elucidated. Microbiome-modulated metabolites are promising targets for new drug discovery due to their endocrine function in various complex disorders. In humans, metabolotherapy for the prevention or treatment of various disorders will be possible if we better understand the metabolic preferences of bacteria and the host in specific tissues and organs. Better disease treatments may be possible with the help of novel complementary therapies that target host or bacterial metabolism. The metabolites, their physiological consequences, and functional mechanisms of the host-microbiota interplays will be highlighted, summarized, and discussed in this overview.

Dissociation and flow cytometric isolation of murine intestinal epithelial cells for multi-omic profiling

Intestinal epithelium is composed of several cell types, which can be dissociated but difficult to maintain high cell viability due to anoikis. Herein, we describe a step-by-step protocol for the isolation of highly viable intestinal epithelial cells using ethylenediaminetetraacetate acid and TrypLE Express, which can subsequently be employed for multi-omic analyses, including single-cell RNA sequencing. For complete details on the use and execution of this protocol, please refer to Ge et al. (2022).1.

Intermediate role of gut microbiota in vitamin B nutrition and its influences on human health

Vitamin B consists of a group of water-soluble micronutrients that are mainly derived from the daily diet. They serve as cofactors, mediating multiple metabolic pathways in humans. As an integrated part of human health, gut microbiota could produce, consume, and even compete for vitamin B with the host. The interplay between gut microbiota and the host might be a crucial factor affecting the absorbing processes of vitamin B. On the other hand, vitamin B supplementation or deficiency might impact the growth of specific bacteria, resulting in changes in the composition and function of gut microbiota. Together, the interplay between vitamin B and gut microbiota might systemically contribute to human health. In this review, we summarized the interactions between vitamin B and gut microbiota and tried to reveal the underlying mechanism so that we can have a better understanding of its role in human health.

Ischemic Stroke Impacts the Gut Microbiome, Ileal Epithelial and Immune Homeostasis

Ischemic stroke critically impacts neurovascular homeostasis, potentially resulting in neurological disorders. However, the mechanisms through which stroke-induced inflammation modifies the molecular and metabolic circuits, particularly in ileal epithelial cells (iECs), currently remain elusive. Using multiomic approaches, we illustrated that stroke impaired the ileal microbiome and associated metabolites, leading to increased inflammatory signals and altered metabolites, potentially deteriorating the iEC homeostasis. Bulk transcriptomic and metabolomic profiling demonstrated that stroke enhanced fatty acid oxidation while reducing the tricarboxylic acid (TCA) cycle in iECs within the first day after stroke. Intriguingly, single-cell RNA sequencing analysis revealed that stroke dysregulated cell-type-specific gene responses within iECs and reduced frequencies of goblet and tuft cells. Additionally, stroke augmented interleukin-17A+ γδ T cells but decreased CD4+ T cells in the ileum. Collectively, our findings provide a comprehensive overview of stroke-induced intestinal dysbiosis and unveil responsive gene programming within iECs with implications for disease development.

Vitamin B12 Regulates the Transcriptional, Metabolic, and Epigenetic Programing in Human Ileal Epithelial Cells

Vitamin B12 (VB12) is a micronutrient that is essential for DNA synthesis and cellular energy production. We recently demonstrated that VB12 oral supplementation coordinates ileal epithelial cells (iECs) and gut microbiota functions to resist pathogen colonization in mice, but it remains unclear whether VB12 directly modulates the cellular homeostasis of iECs derived from humans. Here, we integrated transcriptomic, metabolomic, and epigenomic analyses to identify VB12-dependent molecular and metabolic pathways in human iEC microtissue cultures. RNA sequencing (RNA-seq) revealed that VB12 notably activated genes involved in fatty acid metabolism and epithelial cell proliferation while suppressing inflammatory responses in human iECs. Untargeted metabolite profiling demonstrated that VB12 facilitated the biosynthesis of amino acids and methyl groups, particularly S-adenosylmethionine (SAM), and supported the function of the mitochondrial carnitine shuttle and TCA cycle. Further, genome-wide DNA methylation analysis illuminated a critical role of VB12 in sustaining cellular methylation programs, leading to differential CpG methylation of genes associated with intestinal barrier function and cell proliferation. Together, these findings suggest an essential involvement of VB12 in directing the fatty acid and mitochondrial metabolisms and reconfiguring the epigenome of human iECs to potentially support cellular oxygen utilization and cell proliferation.