Propionate induces intestinal oxidative stress via Sod2 propionylation in zebrafish

Post-translational acylation of proteins in cardiac hypertrophy

Acylations are post-translational modifications in which functional groups are attached to amino acids on proteins. Most acylations (acetylation, butyrylation, crotonylation, lactylation, malonylation, propionylation and succinylation) involve lysine but cysteine (palmitoylation) and glycine (myristoylation) residues can also be altered. Acylations have important roles in physiological and pathophysiological processes, including cardiac hypertrophy and related cardiovascular diseases. These post-translational modifications influence chromatin architecture, transcriptional regulation and metabolic pathways, thereby affecting cardiomyocyte function and pathology. The dynamic interaction between these acylations and their regulatory enzymes, such as histone acetyltransferases, histone deacetylases and sirtuins, underscores the complexity of cellular homeostasis and pathological processes. Emerging evidence highlights the therapeutic potential of targeting acylations to modulate enzyme activity and metabolite levels, offering promising avenues for novel treatments. In this Review, we explore the diverse mechanisms through which acylations contribute to cardiac hypertrophy, highlighting the complexity and potential therapeutic targets in this regulatory network.

Metabolomic profiling of human semen in patients with oligospermia using high performance liquid chromatography-tandem mass spectrometry

Male infertility is one of the most common reproductive dysfunctions. Despite oligospermia being a cause of infertility, few studies have been conducted on it. This study aimed to investigate differences in semen metabolic patterns in patients with oligospermia and to identify potential biomarkers associated with oligospermia. Semen samples from oligospermia patients (20 cases) and healthy controls (20 cases) were detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and 72 and 89 metabolites were identified as potential markers in positive and negative ion modes, respectively. In addition, the results identified multiple metabolic pathways in patients with oligospermia, such as glycine serine and threonine metabolism, Synthesis and degradation of ketone bodies, Valine, leucine, and isoleucine degradation. These results described unique metabolic characteristics of semen in patients with oligospermia and provided novel insights into the mechanism of the semen disorder.

Lysine 2-hydroxyisobutyrylation proteomics analyses reveal the regulatory mechanism of CaMYB61-CaAFR1 module in regulating stem development in Capsicum annuum L

Plant stems constitute the most abundant renewable resource on earth. The function of lysine (K)-2-hydroxyisobutyrylation (Khib), a novel post-translational modification (PTM), has not yet been elucidated in plant stem development. Here, by assessing typical pepper genotypes with straight stem (SS) and prostrate stem (PS), we report the first large-scale proteomics analysis for protein Khib to date. Khib-modifications influenced central metabolic processes involved in stem development, such as glycolysis/gluconeogenesis and protein translation. The high Khib level regulated gene expression and protein accumulation associated with cell wall formation in the pepper stem. Specially, we found that CaMYB61 knockdown lines that exhibited prostrate stem phenotypes had high Khib levels. Most histone deacetylases (HDACs, e.g., switch-independent 3 associated polypeptide function related 1, AFR1) potentially function as the "erasing enzymes" involved in reversing Khib level. CaMYB61 positively regulated CaAFR1 expression to erase Khib and promote cellulose and hemicellulose accumulation in the stem. Therefore, we propose a bidirectional regulation hypothesis of "Khib modifications" and "Khib erasing" in stem development, and reveal a novel epigenetic regulatory network in which the CaMYB61-CaAFR1 molecular module participating in the regulation of Khib levels and biosynthesis of cellulose and hemicellulose for the first time.

Probiotic Pediococcus pentosaceus restored gossypol-induced intestinal barrier injury by increasing propionate content in Nile tilapia

BACKGROUND

Intestinal barrier is a dynamic interface between the body and the ingested food components, however, dietary components or xenobiotics could compromise intestinal integrity, causing health risks to the host. Gossypol, a toxic component in cottonseed meal (CSM), caused intestinal injury in fish or other monogastric animals. It has been demonstrated that probiotics administration benefits the intestinal barrier integrity, but the efficacy of probiotics in maintaining intestinal health when the host is exposed to gossypol remains unclear. Here, a strain (YC) affiliated to Pediococcus pentosaceus was isolated from the gut of Nile tilapia (Oreochromis niloticus) and its potential to repair gossypol-induced intestinal damage was evaluated.

RESULTS

A total of 270 Nile tilapia (2.20 ± 0.02 g) were allotted in 3 groups with 3 tanks each and fed with 3 diets including CON (control diet), GOS (control diet containing 300 mg/kg gossypol) and GP (control diet containing 300 mg/kg gossypol and 108 colony-forming unit (CFU)/g P. pentosaceus YC), respectively. After 10 weeks, addition of P. pentosaceus YC restored growth retardation and intestinal injury induced by gossypol in Nile tilapia. Transcriptome analysis and siRNA interference experiments demonstrated that NOD-like receptors (NLR) family caspase recruitment domain (CARD) domain containing 3 (Nlrc3) inhibition might promote intestinal stem cell (ISC) proliferation, as well as maintaining gut barrier integrity. 16S rRNA sequencing and gas chromatography-mass spectrometry (GC-MS) revealed that addition of P. pentosaceus YC altered the composition of gut microbiota and increased the content of propionate in fish gut. In vitro studies on propionate's function demonstrated that it suppressed nlrc3 expression and promoted wound healing in Caco-2 cell model.

CONCLUSIONS

The present study reveals that P. pentosaceus YC has the capacity to ameliorate intestinal barrier injury by modulating gut microbiota composition and elevating propionate level. This finding offers a promising strategy for the feed industry to incorporate cottonseed meal into fish feed formulations.

Dietary supplementation with inulin improves burn-induced skeletal muscle atrophy by regulating gut microbiota disorders

Inulin, as a prebiotic, could modulate the gut microbiota. Burn injury leads to gut microbiota disorders and skeletal muscle catabolism. Therefore, whether inulin can improve burn-induced muscle atrophy by regulating microbiota disorders remains unknown. This study aimed to clarify that inulin intake alleviates gut microbiota disorders and skeletal muscle atrophy in burned rats. Rats were divided into the sham group, burn group, prebiotic inulin intervention group, and pseudo-aseptic validation group. A 30% total body surface area (TBSA) third-degree burn wound on dorsal skin was evaluated in all groups except the sham group. Animals in the intervention group received 7 g/L inulin. Animals in the validation group received antibiotic cocktail and inulin treatment. In our study inulin intervention could significantly alleviate the burn-induced skeletal muscle mass decrease and skeletal myoblast cell apoptosis. Inulin intake increased the abundances of Firmicutes and Actinobacteria but decreased the abundance of Proteobacteria. The biosynthesis of amino acids was the most meaningful metabolic pathway distinguishing the inulin intervention group from the burn group, and further mechanistic studies have shown that inulin can promote the phosphorylation of the myogenesis-related proteins PI3K, AKT and P70S6K and activate PI3K/AKT signaling for protein synthesis. In conclusion, inulin alleviated burn induced muscle atrophy through PI3K/AKT signaling and regulated gut microbiota dysbiosis.

Mitigation of avermectin exposure-induced brain tissue damage in carp by quercetin

Avermectin is widely used as an important insecticide in agricultural production, but it also shows strong toxicity to non-target organisms. Quercetin is a natural flavonoid that is widely used due to its good anti-inflammatory and antioxidant effects. We believe that quercetin may have a potential therapeutic effect on avermectin poisoning. This experiment was proposed to observe the effect of quercetin on the toxic response to avermectin by observing the toxic response caused by avermectin in the brain of carp. In this project, 60 carp were studied as control group (Control), quercetin administration group (QUE), avermectin exposure group (AVM) and quercetin treatment avermectin exposure group (QUE + AVM) with different interventions to study the effect of quercetin on avermectin. The carp brain tissues were stained and simultaneously analyzed for blood-brain barrier (BBB), oxidative stress indicators, inflammatory factors, and apoptosis using qPCR technique. The results of the study indicate that avermectin exhibits a neurotoxic mechanism of action in fish by decreasing the transcript levels of tight junction protein-related genes, which in turn leads to the rupture of the BBB in the carp brain tissue. Avermectin induced apoptosis in carp brain tissue by increasing oxidative stress response and promoting inflammatory cell infiltration. Quercetin could reduce the accumulation of reactive oxygen species (ROS) in the brain tissue of carp caused by avermectin exposure toxicity, maintain redox homeostasis, reduce inflammatory response, and protect brain tissue cells from apoptosis. The present study confirmed the therapeutic and protective effects of quercetin on neurotoxicity in carp caused by avermectin exposure.

The effect of stabilized culture of Lactobacillus rhamnosus GCC-3 on gut and liver health, and anti-viral immunity of zebrafish

Probiotics are promising antibiotics alternatives to improve growth and disease resistance of cultured fish. Our study aimed to investigate the effect of dietary stabilized culture of Lactobacillus rhamnosus GCC-3 on growth performance, gut and liver health and anti-viral ability of zebrafish (Danio rerio). Zebrafish (0.161 ± 0.001 g) were fed control and the experimental diet containing 1% GCC-3 culture (1 × 107 CFU/g diet) for four weeks. Growth performance and gut and liver health parameters were monitored after four weeks feeding. The gut microbiota was analyzed by 16S rRNA gene sequencing. In another experiment, zebrafish (0.212 ± 0.001 g) were fed with basal or GCC-3 diets and challenged by spring viremia of carp virus (SVCV) at the end of feeding. The antiviral immune response was evaluated at 2nd and 4th days post SVCV infection and survival rate was calculated 14 days after challenge. The results showed that adding 1% GCC-3 significantly improved growth performance of zebrafish (P < 0.05). The intestinal expression of hypoxia-inducible factor Hif-1α, tight junction protein ZO-1α and ZO-1β was significantly up-regulated in 1% GCC-3 group compared with control (P < 0.05). Besides, 1% GCC-3 decreased the content of MDA and increased total antioxidant capacity in the intestine, and the relative expression of SOD, GST and Gpxa was improved. The abundance of Proteobacteria was reduced while Firmicutes was enriched in the intestinal microbiota of 1% GCC-3 group compared with control (P < 0.05). Zebrafish fed 1% GCC-3 showed higher survival rate after SVCV challenge. Accordingly, the expression of antiviral genes in the spleen was increased at 2nd and 4th days post infection. In conclusion, our results indicate that dietary 1% GCC-3 supplementation can improve gut and liver health as well as antiviral immunity of zebrafish.

Proteomic analysis unveils Gb3-independent alterations and mitochondrial dysfunction in a gla-/- zebrafish model of Fabry disease

BACKGROUND

Fabry disease (FD) is a rare lysosomal storage disorder caused by mutations in the GLA gene, resulting in reduced or lack of α-galactosidase A activity. This results in the accumulation of globotriaosylceramide (Gb3) and other glycosphingolipids in lysosomes causing cellular impairment and organ failures. While current therapies focus on reversing Gb3 accumulation, they do not address the altered cellular signaling in FD. Therefore, this study aims to explore Gb3-independent mechanisms of kidney damage in Fabry disease and identify potential biomarkers.

METHODS

To investigate these mechanisms, we utilized a zebrafish (ZF) gla-/- mutant (MU) model. ZF naturally lack A4GALT gene and, therefore, cannot synthesize Gb3. We obtained kidney samples from both wild-type (WT) (n = 8) and MU (n = 8) ZF and conducted proteome profiling using untargeted mass spectrometry. Additionally, we examined mitochondria morphology and cristae morphology using electron microscopy. To assess oxidative stress, we measured total antioxidant activity. Finally, immunohistochemistry was conducted on kidney samples to validate specific proteins.

RESULTS

Our proteomics analysis of renal tissues from zebrafish revealed downregulation of lysosome and mitochondrial-related proteins in gla-/- MU renal tissues, while energy-related pathways including carbon, glycolysis, and galactose metabolisms were disturbed. Moreover, we observed abnormal mitochondrial shape, disrupted cristae morphology, altered mitochondrial volume and lower antioxidant activity in gla-/- MU ZF.

CONCLUSIONS

These results suggest that the alterations observed at the proteome and mitochondrial level closely resemble well-known GLA mutation-related alterations in humans. Importantly, they also unveil novel Gb3-independent pathogenic mechanisms in Fabry disease. Understanding these mechanisms could potentially lead to the development of innovative drug screening approaches. Furthermore, the findings pave the way for identifying new clinical targets, offering new avenues for therapeutic interventions in Fabry disease. The zebrafish gla-/- mutant model proves valuable in elucidating these mechanisms and may contribute significantly to advancing our knowledge of this disorder.

Protein posttranslational modifications in health and diseases: Functions, regulatory mechanisms, and therapeutic implications

Protein posttranslational modifications (PTMs) refer to the breaking or generation of covalent bonds on the backbones or amino acid side chains of proteins and expand the diversity of proteins, which provides the basis for the emergence of organismal complexity. To date, more than 650 types of protein modifications, such as the most well-known phosphorylation, ubiquitination, glycosylation, methylation, SUMOylation, short-chain and long-chain acylation modifications, redox modifications, and irreversible modifications, have been described, and the inventory is still increasing. By changing the protein conformation, localization, activity, stability, charges, and interactions with other biomolecules, PTMs ultimately alter the phenotypes and biological processes of cells. The homeostasis of protein modifications is important to human health. Abnormal PTMs may cause changes in protein properties and loss of protein functions, which are closely related to the occurrence and development of various diseases. In this review, we systematically introduce the characteristics, regulatory mechanisms, and functions of various PTMs in health and diseases. In addition, the therapeutic prospects in various diseases by targeting PTMs and associated regulatory enzymes are also summarized. This work will deepen the understanding of protein modifications in health and diseases and promote the discovery of diagnostic and prognostic markers and drug targets for diseases.

Small-sample learning reveals propionylation in determining global protein homeostasis

Proteostasis is fundamental for maintaining organismal health. However, the mechanisms underlying its dynamic regulation and how its disruptions lead to diseases are largely unclear. Here, we conduct in-depth propionylomic profiling in Drosophila, and develop a small-sample learning framework to prioritize the propionylation at lysine 17 of H2B (H2BK17pr) to be functionally important. Mutating H2BK17 which eliminates propionylation leads to elevated total protein level in vivo. Further analyses reveal that H2BK17pr modulates the expression of 14.7-16.3% of genes in the proteostasis network, and determines global protein level by regulating the expression of genes involved in the ubiquitin-proteasome system. In addition, H2BK17pr exhibits daily oscillation, mediating the influences of feeding/fasting cycles to drive rhythmic expression of proteasomal genes. Our study not only reveals a role of lysine propionylation in regulating proteostasis, but also implements a generally applicable method which can be extended to other issues with little prior knowledge.

Dietary spirulina supplementation modifies rumen development, fermentation and bacteria composition in Hu sheep when consuming high-fat dietary

Introduction

This study aims to investigate the long-term effects of spirulina supplementation in a high-fat diet (HFD) on rumen morphology, rumen fermentation, and the composition of rumen microbiota in lambs. Spirulina is a blue-green microalgae that has been shown to have high nutritional value for livestock.

Methods

Fifty-four lambs were randomly divided into three groups: a normal chow diet (NCD) group, a high-fat diet (HFD) group, and a high-fat diet supplemented with 3% spirulina (HFD+S) group. Rumen morphology, rumen fermentation, and rumen microbiota were analyzed at the end of the study.

Results

Spirulina supplementation improved the concentration of volatile fatty acids and rumen papilla length. Additionally, there was a tendency for an increase in rumen weight and an upregulation of the genes Claudin-1, Claudin-4, and Occludin in the HFD+S group. Pyrosequencing of the 16S ribosomal RNA gene also showed that spirulina supplementation significantly changed the rumen microbiota composition in the HFD group, with a decrease in richness and diversity. Specifically, the relative abundance of Prevotella 9 and Megasphaera was significantly increased in the HFD group compared to the NCD group, while spirulina supplementation reversed these changes.

Discussion

This study suggests that 3% spirulina supplementation can improve rumen development and fermentation, and effectively relieve rumen microbe disorders in lambs caused by a high-fat diet. However, further research is needed to confirm the findings and to examine the long-term effects of spirulina supplementation in different types of livestock and under different dietary conditions.

Acylations in cardiovascular biology and diseases, what's beyond acetylation

Metabolism regulates cardiovascular biology through multiple mechanisms, including epigenetic modifications. Over the past two decades, experimental and preclinical studies have highlighted the critical roles of histone modifications in cardiovascular development, homeostasis, and diseases. The widely studied histone acetylation is critical in cardiovascular biology and diseases, and inhibitors of histone deacetylases show therapeutic values. In addition to lysine acetylation, a series of novel non-acetyl lysine acylations have recently been recognized. These non-acetyl lysine acylations have been demonstrated to have physiological and pathological functions, and recent studies have analyzed the roles of these non-acetyl lysine acylations in cardiovascular biology. Herein, we review the current advances in the understanding of non-acetyl lysine acylations in cardiovascular biology and discuss open questions and translational perspectives. These new pieces of evidence provide a more extensive insight into the epigenetic mechanisms underlying cardiovascular biology and help assess the feasibility of targeting acylations to treat cardiovascular diseases.

The effect and underlying mechanism of yeast β-glucan on antiviral resistance of zebrafish against spring viremia of carp virus infection

β-glucan has been used as immunostimulant for fish. However, the effect of yeast β-glucan on viral infections has been less studied in fish. In this study, we investigated the effects of β-glucan on the resistance of zebrafish against spring viraemia of carp virus (SVCV) and elucidated the underlying mechanisms. Zebrafish were fed with a control diet or diet supplemented with 0.01% and 0.025% β-glucan for 2 weeks, and were challenged by SVCV. Zebrafish embryonic fibroblast (ZF4) cells were treated with 5 μg/mL β-glucan and were infected by SVCV. We further investigated the effect of β-glucan on autophagy level post SVCV infection. The intestinal microbiota was evaluated by 16S rRNA gene pyrosequencing. Results showed that dietary supplementation of 0.025% β-glucan significantly increased survival rate of zebrafish compared with control group after SVCV challenge (P < 0.05). Dietary β-glucan significantly increased the expression of genes related to type I IFN antiviral immune pathway in the spleen of zebrafish after viral infection, including type I IFN genes (ifnφ1, ifnφ2, ifnφ3), IFN-stimulated genes (mxb, mxc), as well as other genes involved in the IFN signaling pathway, including tlr7, rig1, mavs, irf3 and irf7. Morpholino knockdown of type I IFN receptors dampened the antiviral effect of β-glucan in zebrafish larvae, indicating that β-glucan-mediated antiviral function was at least partially dependent on IFN immune response. Furthermore, β-glucan can inhibit the replication of SVCV in ZF4 cells. However, β-glucan did not stimulate type I IFN antiviral response in ZF4 cells, and the antiviral effect of β-glucan in ZF4 was independent of Myd88. Interestingly, β-glucan induced autophagy in ZF4 cells after SVCV infection. Inhibition of autophagy blocked the antiviral effect of β-glucan in ZF4 cells. Lastly, dietary β-glucan changed the composition of intestinal microbiota in zebrafish, with reduced abundance of Proteobacteria and an enrichment of Fusobacteria and Firmicutes. To sum up, our results indicate that the β-glucan enhanced resistance of zebrafish against SVCV and the mechanism involved stimulation of type I IFN antiviral immune response of fish after viral infection.

The Effects of Sodium Propionate Supplementation in the Diet with High Soybean Meal on Growth Performance, Intestinal Health, and Immune Resistance to Bacterial Infection in Turbot (Scophthalmus maximus L.)

Short-chain fatty acids (SCFAs) are the products of the microbial fermentation of dietary fiber in the intestine. Acetate, propionate, and butyrate are the most abundant SCFA metabolites and play an important role in maintaining host health. This study was aimed at investigating the effects of sodium propionate (NaP) supplementation in the diet with a high proportion of soybean meal (SBM) on the growth, inflammatory status, and anti-infectious ability in juvenile turbot. Four experimental diets were designed: (1) fish meal- (FM-) based diet (control group), (2) SBM protein replacing 45% FM protein in the diet (high SBM group), (3) 0.5% NaP supplementation in the high SBM diet (high SBM+0.5% NaP group), and (4) 1.0% NaP supplementation in the high SBM diet (high SBM+1.0% NaP group). The results confirmed that the fish fed the high SBM diet for 8 weeks showed the decreased growth performance, the typical enteritis symptoms, and the increased mortality responding to Edwardsiella tarda (E. tarda) infection. However, 0.5% NaP supplementation in the high SBM diet promoted the growth performance of turbot and restored the activities of digestive enzymes in the intestine. Moreover, dietary NaP ameliorated the intestinal morphology, enhanced the expression of intestinal tight junction proteins, improved the antioxidant capacity, and suppressed the inflammatory status in turbot. Finally, the expression of antibacterial components and the resistance to bacterial infection were increased in NaP-fed turbot, especially in high SBM+1.0% NaP group. In conclusion, the supplementation of NaP in high SBM diet promotes the growth and health in turbot and provides a theoretical basis for the development of NaP as a functional additive in fish feed.

Exposure of zebrafish embryos to sodium propionate disrupts circadian behavior and glucose metabolism-related development

Sodium propionate is widely used as a preservative in food. The widespread use of preservatives is known to cause both environmental and public health problems. This study aimed to investigate the effects of sodium propionate on the developmental behavior and glucose metabolism of zebrafish. Our results showed that sodium propionate had no significant effect on the embryonic morphological development of zebrafish embryos but changed the head eye area. Then we found sodium propionate disturbed the thigmotaxis behavior, impaired neural development. Moreover, changes in clock gene expression disrupted the circadian rhythm of zebrafish. Circadian genes regulated insulin sensitivity and secretion in various tissues. Then our results showed that the disorder of circadian rhythm in zebrafish affected glucose metabolism and insulin resistance, which damaged the development of retina. Therefore, the safety of propionate should be further evaluated.

Nuclease-Treated Stabilized Fermentation Product of Cetobacterium somerae Improves Growth, Non-specific Immunity, and Liver Health of Zebrafish (Danio rerio)

High-fat diets (HFD) are harmful to fish health. Probiotics are commonly utilized to improve fish nutrition metabolism, immune response, and health. Nucleic acids of the probiotic bacterium can be hydrolyzed by nuclease to generate nucleotides. The present study aimed to evaluate the effects of stabilized fermentation product of nuclease-treated Cetobacterium somerae XMX-1 [XMX-1 (N)] on growth, non-specific immunity, and liver health of zebrafish (Danio rerio). Compared to the HFD group, 100 g/kg XMX-1 (N) significantly increased weight gain and decreased feed conversion ratio (FCR). However, 5 or 10 g/kg XMX-1 (N) had no influence on zebrafish growth. In addition, supplementation of 100 g/kg XMX-1 (N) significantly increased lysozyme activity and total antioxidant capacity in skin mucus, and the expression of inflammation related genes interleukin 1 beta (IL-1β), interleukin 10 (IL-10), and interleukin 6 (IL-6) in the gut as well as fatty acid oxidation related genes uncoupling protein 2 (UCP2) and proliferator-activated receptor γ coactivator 1α (PGC1α) in the liver, while decreased the content of hepatic triacylglycerol (TAG) in zebrafish. The gene sequencing, 16S rRNA, showed that 100 g/kg XMX-1 (N) enhanced the relative abundance of Firmicutes while lowered Proteobacteria and Actinobacteria. 10 g/kg XMX-1 (N) significantly increased lysozyme activity and complement component 4 (C4) in skin mucus, and intestinal expression of inflammation-related genes. In the 5 g/kg XMX-1 (N) group, however, only an increase in C4 level in skin mucus was observed. Together, these results reveal that dietary supplementation with nuclease-treated C. somerae XMX-1 (N) has a dose-dependent beneficial effect on fish health.

Lactobacillus plantarum Ameliorates High-Carbohydrate Diet-Induced Hepatic Lipid Accumulation and Oxidative Stress by Upregulating Uridine Synthesis

The overconsumption of carbohydrates induces oxidative stress and lipid accumulation in the liver, which can be alleviated by modulation of intestinal microbiota; however, the underlying mechanism remains unclear. Here, we demonstrated that a strain affiliated with Lactobacillus plantarum (designed as MR1) efficiently attenuated lipid deposition, oxidative stress, as well as inflammatory response, which are caused by high-carbohydrate diet (HC) in fish with poor utilization ability of carbohydrates. Serum untargeted metabolome analysis indicated that pyrimidine metabolism was the significantly changed pathway among the groups. In addition, the content of serum uridine was significantly decreased in the HC group compared with the control group, while it increased by supplementation with L. plantarum MR1. Further analysis showed that addition of L. plantarum MR1 reshaped the composition of gut microbiota and increased the content of intestinal acetate. In vitro experiment showed that sodium acetate could induce the synthesis of uridine in hepatocytes. Furthermore, we proved that uridine could directly ameliorate oxidative stress and decrease liver lipid accumulation in the hepatocytes. In conclusion, this study indicated that probiotic L. plantarum MR1 ameliorated high-carbohydrate diet-induced hepatic lipid accumulation and oxidative stress by increasing the circulating uridine, suggesting that intestinal microbiota can regulate the metabolism of nucleotides to maintain host physiological homeostasis.