Gut microbiome alterations in high-fat-diet-fed mice are associated with antibiotic tolerance

2,3,7,8-tetrachlorodibenzofuran modulates intestinal microbiota and tryptophan metabolism in mice

Persistent organic pollutants (POPs) are known to disrupt gut microbiota composition and host metabolism, primarily through dietary exposure. In this study, we investigate the impact of 2,3,7,8-tetrachlorodibenzofuran (TCDF) on gut microbiota and host metabolic processes. RNA-seq analysis revealed that TCDF exposure significantly affected tryptophan metabolism, lipid metabolic pathways, and immune system function. Metagenomic and metabolomic analyses further showed that TCDF reduced the abundance of Mucispirillum schaedleri and levels of two key tryptophan metabolites, indole-3-carboxaldehyde (3-IAld) and Indole acrylic acid (IA). Supplementation with 3-IAld and IA alleviated TCDF-induced liver toxicity in mouse, as evidenced by reduced Cyp1a1 expression, and mitigated intestinal inflammation, reflected by lower pro-inflammatory cytokines (Ifn-γ and Il-1β) in the colon. Additionally, 3-IAld and IA supplementation enhanced intestinal barrier function, as demonstrated by increased Mucin 2 (MUC2) expression in the gut mucosa of mouse. These findings suggest that TCDF exposure disrupts the gut microbiome and host metabolic balance, and highlight the potential therapeutic role of tryptophan-derived metabolites in mitigating environmental pollutant-induced damage.

Tryptophan Indole Derivatives: Key Players in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a complex clinical syndrome characterized by insulin resistance and associated with abnormal amino acid metabolism. Tryptophan is an aromatic dietary amino acid that affects T2DM by regulating glycolipid metabolism and insulin resistance. When tryptophan reaches the intestine, it is converted by gut microbiota and tryptophanase into indole derivatives such as indoleacetic acid, indolepropionic acid, and indolealdehyde. These indole derivatives may enhance insulin sensitivity, stimulate insulin secretion, and exert functions such as lowering blood glucose, regulating hepatic oxidative stress, reducing intestinal inflammation, and improving islet cell morphology by acting on the aryl hydrocarbon receptor (AHR) or Pregnane X receptor (PXR). In summary, this review aims to examine the interactions between tryptophan indole derivatives and T2DM thoroughly, elucidate potential therapeutic approaches, and pinpoint areas for further research.

Self-assembly pH-sensitive polyelectrolyte complex co-delivers niclosamide and colistin to overcome colistin resistance in bacterial infections

Polyelectrolyte complexes (PECs) provided new opportunities for drug-controlled release systems and had the potential to address the challenges during the effective oral delivery of colistin and niclosamide. Here, an innovative pH-sensitive PEC for the oral co-delivery of colistin and niclosamide (CS/AL-PECs@COL/NIC) was developed, which was self-assembled through electrostatic interaction by an optimized double-emulsion method from two oppositely charged nanoparticles (chitosan-coated nanoparticles and alginate-coated nanoparticles). The CS/AL-PECs@COL/NIC exhibited pH sensitivity, formed a tight cross-linked structure in the gastric acid environment, effectively slowing down the release of the loaded drugs (colistin and niclosamide), and transformed into a loose structure in the neutral environment of the intestine, facilitating the stable release of the loaded drugs. Importantly, the CS/AL-PECs@COL/NIC had good in vivo antibacterial activity against E. coli infection and alleviated the inflammation and intestinal damage caused by bacterial infection in the mouse intestinal infection model. Both in vitro and in vivo studies indicated that the CS/AL-PECs@COL/NIC had good biocompatibility and good palatability. In particular, the oral administration of an effective dose of CS/AL-PECs@COL/NIC did not cause intestinal flora disorder, which had an advantage over colistin treatment. Thus, the prepared CS/AL-PECs@COL/NIC may contribute to treating colistin-resistant bacterial infections as a biocompatible oral administration.

Metabolic state-driven nutrient-based approach to combat bacterial antibiotic resistance

To combat antibiotic resistance, one innovative approach, known as the metabolic state-driven approach, exploits the fact that exogenous nutrient metabolites can stimulate uptake of antibiotics. The most effective nutrient metabolites are identified by comparing metabolic states between antibiotic-sensitive and -resistant bacteria. When bacteria are exposed to the specific nutrient metabolites, they undergo a form of metabolic reprogramming. This review summarizes the recent progress on the metabolic state-driven approach.

Diet-driven diversity of antibiotic resistance genes in wild bats: implications for public health

Wild bats may serve as reservoirs for antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria, potentially contributing to antibiotic resistance and pathogen transmission. However, current assessments of bats' antibiotic resistance potential are limited to culture-dependent bacterial snapshots. In this study, we present metagenomic evidence supporting a strong association between diet, gut microbiota, and the resistome, highlighting bats as significant vectors for ARG propagation. We characterized gut microbiota, ARGs, and mobile genetic elements (MGEs) in bats with five distinct diets: frugivory, insectivory, piscivory, carnivory, and sanguivory. Our analysis revealed high levels of ARGs in bat guts, with limited potential for horizontal transfer, encompassing 1106 ARGs conferring resistance to 26 antibiotics. Multidrug-resistant and polymyxin-resistant genes were particularly prevalent among identified ARG types. The abundance and diversity of ARGs/MGEs varied significantly among bats with different dietary habits, possibly due to diet-related differences in microbial composition. Additionally, genetic linkage between high-risk ARGs and multiple MGEs was observed on the genomes of various zoonotic pathogens, indicating a potential threat to human health from wild bats. Overall, our study provides a comprehensive analysis of the resistome in wild bats and underscores the role of dietary habits in wildlife-associated public health risks.

Exercise-driven gut microbiota alterations enhance colonization resistance against methicillin-resistant Staphylococcus aureus

Gut microbiota plays a crucial role in resisting the invasion of pathogens, particularly multidrug-resistant (MDR) bacteria, which pose a significant threat to public health. While exercise offers numerous health benefits, its impact on host colonization resistance remains largely unclear. In this study, we demonstrate that moderate exercise significantly reduces gut colonization by methicillin-resistant Staphylococcus aureus (MRSA), a clinically important MDR pathogen. Moreover, we identify an understudied strain of the intestinal probiotic Dubosiella newyorkensis (L8) as a critical factor in mediating exercise-induced colonization resistance against MRSA. Mechanistically, L8 enhances the deprivation of fucose, a crucial carbon source essential for MRSA growth and pathogenicity. This process relies on the high binding affinity of pyruvate to the ILE257 site of the lactate dehydrogenase in L8. Overall, our work highlights the importance of moderate exercise in maintaining host colonization resistance and demonstrates L8 as a probiotic in protecting against MRSA colonization.

Plant based enteral nutrition outperforms artificial nutrition in mitigating consequences of antibiotic-induced dysbiosis in mice and humans

Malnutrition, gut inflammation, and antibiotic induced dysbiosis (AID) are omnipresent risk factors for poor clinical outcomes among critically ill patients. We previously showed that commercially available plant-based enteral nutrition (PBEN) preserves a commensal microbiome when compared to commonly used forms of commercially available artificial enteral nutrition (AEN). This study reveals that PBEN is superior to artificial enteral nutrition (AEN) in recovering from antibiotic-induced dysbiosis (AID) in mice and humans. PBEN effectively mitigates anemia, leukopenia, restores naïve lymphocyte populations, and reduces bone marrow myeloid cell expansion. Animals randomized to PBEN also fared better in response to infectious challenges after antibiotics. A pilot clinical study validated these findings, showing increased gut commensals, reduced pathogens, and improved leukocyte balance in critically ill patients receiving PBEN compared to AEN. These results suggest PBEN offers a practical dietary approach to mitigate antibiotic-associated complications and improve clinical outcomes among hospitalized patients requiring supplemental nutrition.

Vitamin B6 resensitizes mcr-carrying Gram-negative bacteria to colistin

Antimicrobial resistance poses a severe threat to human health, with colistin serving as a critical medication in clinical trials against multidrug-resistant Gram-negative bacteria. However, the efficacy of colistin is increasingly compromised due to the rise of MCR-positive bacteria worldwide. Here, we reveal a notable metabolic disparity between mcr-positive and -negative bacteria through transcriptome and metabolomics analysis. Specifically, pyridoxal 5'-phosphate (PLP), the active form of vitamin B6, was significantly diminished in mcr-positive bacteria. Conversely, supplementing with PLP could reverse the metabolic profile of drug-resistant bacteria and effectively restore colistin's bactericidal properties. Mechanistically, PLP was found to augment bacterial proton motive force by inhibiting the Kdp transport system, a bacterial K+ transport ATPase, thereby facilitating the binding of the positively charged colistin to the negatively charged bacterial membrane components. Furthermore, PLP supplementation triggers ferroptosis-like death by accumulating ferrous ions and inducing lipid peroxidation. These two modes of action collectively resensitize mcr-harboring Gram-negative bacteria to colistin therapy. Altogether, our study provides a novel metabolic-driven antibiotic sensitization strategy to tackle antibiotic resistance and identifies a potentially safe antibiotic synergist.

Poly-γ-glutamic acid alleviates slow transit constipation by regulating aquaporin and gut microbes

Slow transit constipation (STC) is a prevalent gastrointestinal disorder caused by colon dysfunction. Poly-γ-glutamic acid (γ-PGA), an anionic polymer known for its moisture retention, degradability, and food safety, was studied for its effects on loperamide-induced STC in mice. Treatment with γ-PGA for one week significantly increased both defecation frequency and fecal water content, with the high-dose group (10 g/kg/d) restoring fecal water content to 34.23%, outperforming the low- (16.16%) and medium-dose (27.08%) groups and exceeding the positive control, PEG, by 1.35 times. γ-PGA enhanced intestinal peristalsis and reduced the expression of inflammatory markers (IL-1β, IL-6, caspase-1, TLR2) and water-electrolyte transport genes (AQP3, AQP4, ENaC-β), while improving the expression of tight junction proteins (Claudin-1, Occludin, ZO-1) damaged by loperamide. Histopathological analyses confirmed γ-PGA's capacity to repair intestinal damage. Additionally, Western Blot analysis indicated reduced AQP3/4 levels in the colon, and molecular docking showed good binding affinity between γ-PGA and AQPs. γ-PGA also positively altered gut microbiota composition. Overall, γ-PGA shows promise in treating STC by modulating aquaporins and gut microbiota.

Quercetin-Driven Akkermansia Muciniphila Alleviates Obesity by Modulating Bile Acid Metabolism via an ILA/m6A/CYP8B1 Signaling

Global health is increasingly challenged by the growing prevalence of obesity and its associated complications. Quercetin, one of the most important dietary flavonoids, is being explored as an effective therapy for obesity with its mechanism remains understudied. Here in this study, it is demonstrated that quercetin intervention significantly reverses obesity-related phenotypes through reshaping the overall structure of microbiota, especially boosting colonization of the beneficial gut commensal Akkermansia muciniphila (A. muciniphila). Enrichment of A. muciniphila leads to generate more indole-3-lactic acid (ILA) to upregulate the expression of 12α-hydroxylase (CYP8B1) via fat mass and obesity-associated protein (FTO)/ N6-methyladenosine (m6A)/YTHDF2 manner, thereby facilitating cholesterol converts to cholic acid (CA). CA in turn drastically suppresses lipid accumulation via activating the farnesoid X receptor (FXR) in adipose tissue. This work introduces a novel therapeutic target for addressing obesity and expands upon the current limited understanding of the mediator function of m6A modifications in microorganism-influenced bile acid (BA) metabolism.

E. coli Nissle 1917 improves gut microbiota composition and serum metabolites to counteract atherosclerosis via the homocitrulline/Caspase 1/NLRP3/GSDMD axis

BACKGROUND

The probiotic E. coli Nissle 1917 (EcN) alleviates the progression of various diseases, including colitis and tumors. However, EcN has not been studied in atherosclerosis. The study investigated the effects of EcN on atherosclerosis model mice and the potential mechanisms.

METHODS

Mice in the high-fat diet (HFD) model were given EcN (1 × 109 CFU/g) or homocitrulline (150 mg/L) by oral administration for 12 weeks. The EcN + antibiotic group was set up to investigate the effects of EcN combined with antibiotics on gut microbiota. The control group was utilized as the negative control. Atherosclerosis status, pyroptosis, gut microbiota, and serum metabolites of mice were examined.

RESULTS

EcN treatment alleviated HFD-caused atherosclerotic plaque and lipid droplet production. EcN treatment reversed HFD-induced increases in total cholesterol, triglycerides, and low-density lipoprotein levels and decreases in high-density lipoprotein levels. EcN inhibited the HFD-caused rise in the expression of pyroptosis-related indicators (cleaved Caspase 1, GSDMD-N, NLRP3, IL-18, and IL-1β). The antibiotics partially reversed the effects of EcN on the model mice, suggesting that EcN regulated pyroptosis in the model mice through gut microbiota. Probiotic bacteria, such as Lactobacillus and Muribaculum, were mainly enriched in the EcN and EcN + antibiotic groups, while Helicobacter, Alistipes, and Rikenella were depleted, suggesting that EcN and EcN + antibiotics could alleviate disorders of gut microbiota in the model mice. EcN reversed the trend of HFD-induced decrease of some metabolites, such as 2-methyl-5-nitroimidazole-1-ethanol, methionine sulfoxide, and shikimate 3-phosphate, and inhibited the increase of some metabolites, such as kynurenine, oxoadipate, and homocitrulline. In addition, homocitrulline showed the opposite effects of EcN in the model mice. Homocitrulline could bind to pyroptosis-related proteins to aggravate ox-LDL-induced endothelial cell pyroptosis.

CONCLUSION

EcN could alleviate atherosclerosis development by ameliorating HFD-induced disorders of gut microbiota and serum metabolites (such as homocitrulline) to alleviate pyroptosis, which may be associated with homocitrulline/Caspase 1/NLRP3/GSDMD axis. Our study lays the foundation for the development of promising drugs for atherosclerosis in the future.

Betulinic acid from Inonotus obliquus ameliorates T2DM by modulating short-chain fatty acids producing bacteria and amino acids metabolism in db/db mice

ETHNOPHARMACOLOGICAL RELEVANCE

Inonotus obliquus has also been used as a traditional folk medicine in Europe and Northeastern China to treat metabolic diseases. Betulinic acid (BA) is a major ingredient with anti-diabetic property derived from I. obliquus, however, its bioavailability is limited. Whether the beneficial effects of BA on type 2 diabetic mellitus (T2DM) referring to modulation of gut microbiota and associated metabolites remain unclear.

AIM OF THE STUDY

This work aims to investigate the alleviating effect of BA on T2DM in db/db mice and elucidate the mechanism from perspective of network pharmacology, gut microbiome and fecal metabolome.

MATERIALS AND METHODS

BA was orally administered to db/db mice for 45 days, and the related biochemical parameters were evaluated. The associated mechanism was explored using network pharmacology analysis, 16S rRNA sequencing and UHPLC-MS metabolomics comprehensively. Additionally, Spearman analysis was performed to assess the correlation between gut microbes, metabolites, and T2DM-related biochemical parameters.

RESULTS

BA ameliorated T2DM symptoms by reducing body weight gain, regulating serum glucose and lipid levels, and mitigating T2DM-associated liver injury in db/db mice. Network pharmacology analysis indicated the ameliorative effect was via targeting at PPAR activity. BA intervention increased the relative abundance of short-chain fatty acids (SCFAs) producing bacteria including Lactobacillus and Eubacterium_xylanophilum group, and enhanced the production of SCFAs. Moreover, BA primarily regulates arginine and proline metabolism, D-glutamine and D-glutamate metabolism, and alanine, aspartate and glutamate metabolism. Spearman analysis indicated a negative correlation between SCFAs-producing bacteria and amino acids, as well as serum glucose and lipid levels.

CONCLUSION

Apart from PPAR signaling pathway, BA modulated gut microbiota composition and associated metabolites in db/db mice. This study provided novel insights into the therapeutic potential of BA for alleviating T2DM symptoms.

Epidemiological surveys, antibiotic resistance, and related risk factors of Helicobacter pylori in Quanzhou, China: a cross-sectional study

This study aims to investigate the prevalence and association between characteristics, dietary habits, and other factors associated to Helicobacter pylori (H. pylori) infection, as well as the resistance of H. pylori to antibiotics and risk factors in Quanzhou. A minimally invasive string test combined with qPCR was used to investigate the relationship between H. pylori infection and several factors that were evaluated using a survey. Logistic analyses were performed to estimate the risk factors for the prevalence and antibiotic resistance of H. pylori. The H. pylori prevalence amounted to 52.60%, the clarithromycin and levofloxacin resistance rate of H. pylori were 48.92% and 44.59%, respectively. Logistic analyses showed that takeaway food emerged as a protective factor for H. pylori infection, while the consumption of soy products reduced the risk of clarithromycin resistance. Furthermore, high sugar, spicy food, frequent tea drinking, and hyperlipidemia increased the risk of H. pylori infection. Finally, the frequency of oral hygiene had an impact on levofloxacin resistance. The prevalence and resistance rate of H. pylori was found to be high in Quanzhou. Our results also showed that diet, hygiene, and disease prevention awareness play an importance role in H. pylori prevention and treatment.

Microbiota-derived 3-Methyl-L-histidine mediates the proatherogenic effect of high chicken protein diet

Diet rich in chicken protein has gained a widespread popularity for its profound effect on weight loss and glycemic control; however, its long-term effect on cardiovascular health and the underlying mechanisms remains obscure. Here, we demonstrated that higher intake of chicken protein was an independent risk factor for sub-clinical atherosclerosis. Adherence to high chicken protein diet (HCD) alleviated excessive weight gain and glycemic control regardless of the presence of gut microbiota in apolipoprotein E-deficient mice. In contrast, long-term HCD administration enhanced intestinal cholesterol absorption and accelerated atherosclerotic plaque formation in a gut microbiota-dependent manner. Integrative analysis of 16S rDNA sequencing and metabolomics profiling identified 3-Methyl-L-histidine (3-MH), resulting from an enrichment of Lachnospiraceae, as the key microbial effector to the atherogenic effect of HCD. Mechanistically, 3-MH facilitated the binding of hepatocyte nuclear factor 1A (HNF1A) to the promoter of NPC1-like intracellular cholesterol transporter 1 (NPC1L1), whereas inhibition of HNF1A-NPC1L1 axis abolished the atherogenic effect of 3-MH. Our findings uncovered a novel link between microbiota-derived 3-MH and disturbed cholesterol homeostasis, which ultimately accelerated atherosclerosis, and argued against the recommendation of HCD as weight loss regimens considering its adverse role in vascular health.

Gut-Derived Ursodeoxycholic Acid from Saponins of Quinoa Regulated Colitis via Inhibiting the TLR4/NF-κB Pathway

Alteration of the gut microbiota and its metabolites plays a key role in the development of inflammatory bowel disease (IBD). Here, we investigated the mechanism of saponins, a byproduct from quinoa (SQ) processing, in regulating IBD. SQ ameliorated gut microbiota dysbiosis revealed by 16S rRNA sequencing and improved colonic antioxidant activities and barrier integrity in dextran sulfate sodium (DSS)-treated mice. Broad-spectrum antibiotics further proved that the gut-protective effects of SQ were mediated by gut microbiota. Next, fecal microbiota transplantation (FMT) of SQ-induced gut microbiota/metabolites to inoculate DSS-treated mice alleviated colitis significantly. Untargeted metabolomics and lipidomics revealed that ursodeoxycholic acid (UDCA) was enriched as a microbial metabolite after SQ supplementation. UDCA was then found to attenuate DSS-induced colitis in vivo by targeting the TLR4/NF-κB pathway, which was also verified in a Caco-2 cell model treated with a TLR4 agonist/antagonist. Overall, our findings established that gut microbiota-UDCA-TLR4/NF-κB signaling plays a key role in mediating the protective effects of SQ.

Lactobacillus helveticus LZ-R-5 Ameliorates DSS-Induced Colitis in Mice by Modulating Gut Microbiota and Enhancing Intestinal Barrier Function

Lactobacillus helveticus LZ-R-5 (R-5), a strain with high epithelial adhesion and bioactive exopolysaccharide production, was isolated from Tibetan kefir grains. This study investigated its potential to alleviate intestinal inflammation using a DSS-induced colitis model in BALB/c mice. We integrated microbial diversity and serological analyses to assess changes in gut flora and cytokines following the R-5 treatment. Pathological assessments showed that R-5 reduced crypt distortion in the proximal colon and mitigated hepatic immune challenges by enhancing gut barrier function. The increased relative expression of TGF-β1 and the downregulation of NLRP3-related inflammatory factors were conducive to preventing organ damage in the thymus and spleen of mice with colitis. Additionally, R-5 stimulated GPR43 expression and improved epithelial nutrition, promoting mucin production to prevent enterotoxin leakage. It also modulated the gut microbiota by suppressing Bacteroides and Erysipelatoclostridium, leading to a microbiota composition more akin to that of normal flora.

Methionine-driven methylation modification overcomes plasmid-mediated high-level tigecycline resistance

Tigecycline is a last-resort antibiotic to treat complicated infections caused by multidrug-resistant pathogens, while the emergence of plasmid-mediated tet(X) family severely compromises its clinical efficacy. Novel antimicrobial strategies not limited to new antibiotics in pharmaceutical pipeline are urgently needed. Herein, we reveal the metabolic disparities between tet(X)-negative and -positive E. coli, including distinct energy demand patterns under tigecycline exposure. In particular, the cysteine and methionine metabolism pathway is remarkably downregulated in tet(X)-positive bacteria. More importantly, we find that the addition of exogenous L-methionine (Met) effectively resensitizes tet(X)-positive pathogens to tigecycline. Our mechanistic analysis demonstrates that exogenous Met promotes intracellular tigecycline accumulation by upregulating bacterial proton motive force. Moreover, Met accelerates the conversion to S-adenosyl-L-methionine, an essential methyl donor, thereby enhancing 5mC methylation modification in the promoter region of tet(X4) gene and reducing its expression. Consistently, the potentiation of Met to tigecycline is abolished in tet(X4)-carrying E. coli Δdcm but restored in dcm-complementary bacteria, which encodes DNA-cytosine methyltransferase. In multiple animal models of infection, Met markedly potentiates the effectiveness of tigecycline against pathogenic E. coli and K. pneumoniae. Overall, this work highlights the therapeutic potential of Met in overcoming plasmid-mediated high-level tigecycline resistance, and provides a new paradigm to enhance antibiotic efficacy by harnessing cellular metabolic networks as well as epigenetic modifications.

Low Phosphorus Causes Hepatic Energy Metabolism Disorder Through Dynamin-Related Protein 1-Mediated Mitochondrial Fission in Fish

BACKGROUND

Low phosphorus (LP) diets perturb hepatic energy metabolism homeostasis in fish. However, the specific mechanisms in LP-induced hepatic energy metabolism disorders remain to be fully elucidated.

OBJECTIVES

This study sought to elucidate the underlying mechanisms of mitochondria involved in LP-induced energy metabolism disorders.

METHODS

Spotted seabass were fed diets with 0.72% (S-AP, control) or 0.36% (S-LP) available phosphorus for 10 wk. Drp1 was knocked down or protein kinase (PK) A was activated using 8Br-cAMP (5 μM, a PKA activator) in spotted seabass hepatocytes under LP medium. Zebrafish were fed Z-LP diets (0.30% available phosphorus) containing Mdivi-1 (5 mg/kg, a Drp1 inhibitor) or 8Br-cAMP (0.5 mg/kg) for 6 wk. Biochemical and molecular parameters, along with transmission electron microscopy and immunofluorescence, were used to assess hepatic glycolipid metabolism, mitochondrial function, and morphology.

RESULTS

Spotted seabass fed S-LP diets showed reduced ATP (52%) and cAMP (52%) concentrations, along with reduced Drp1 (s582) (38%) and PKA (61%) phosphorylation concentrations in the liver compared with those fed S-AP diets (P < 0.05). Drp1 knockdown elevated ATP concentrations (1.99-fold), decreased mitochondrial DRP1 protein amounts (45%), and increased mitochondrial aspect ratio (1.82-fold) in LP-treated hepatocytes (P < 0.05). Furthermore, 8Br-cAMP-treated hepatocytes exhibited higher PKA phosphorylation (2.85-fold), ATP concentrations (1.60-fold), and mitochondrial aspect ratio (2.00-fold), along with decreased mitochondrial DRP1 protein concentrations (29%) under LP medium (P < 0.05). However, mutating s582 to alanine mimic Drp1 dephosphorylation decreased ATP concentrations (63%) and mitochondrial aspect ratio (53%) in 8Br-cAMP-treated hepatocytes (P < 0.05). In addition, zebrafish fed Z-LP diets containing Mdivi-1 or 8Br-cAMP had higher ATP concentrations (3.44-fold or 1.98-fold) than those fed Z-LP diets (P < 0.05).

CONCLUSIONS

These findings provide a potential mechanistic elucidation for LP-induced energy metabolism disorders through the cAMP/PKA/Drp1-mediated mitochondrial fission signaling pathway.

Brd4 modulates metabolic endotoxemia-induced inflammation by regulating colonic macrophage infiltration in high-fat diet-fed mice

High-fat diet (HFD) induces low-grade chronic inflammation, contributing to obesity and insulin resistance. However, the precise mechanisms triggering obesity-associated metabolic inflammation remain elusive. In this study, we identified epigenetic factor Brd4 as a key player in this process by regulating the expression of Ccr2/Ccr5 in colonic macrophage. Upon 4-week HFD, myeloid-lineage-specific Brd4 deletion (Brd4-CKO) mice showed reduced colonic inflammation and macrophage infiltration with decreased expression of Ccr2 and Ccr5. Mechanistically, Brd4 was recruited by NF-κB to the enhancer regions of Ccr2 and Ccr5, promoting enhancer RNA expression, which facilitated Ccr2/Ccr5 expression and macrophage migration. Furthermore, decreased infiltration of Ccr2/Ccr5-positive colonic macrophages in Brd4-CKO mice altered gut microbiota composition and reduced intestinal permeability, thereby lowering metabolic endotoxemia. Finally, Brd4-CKO mice subjected to a 4-week LPS infusion exhibited restored susceptibility to HFD-induced obesity and insulin resistance. This study identifies Brd4 as a critical initiator of colonic macrophage-mediated inflammation and metabolic endotoxemia upon HFD, suggesting Brd4 as a potential target for mitigating HFD-induced inflammation, obesity, and its metabolic complications.

Exploring tryptophan metabolism: The transition from disturbed balance to diagnostic and therapeutic potential in metabolic diseases

The rapidly rising prevalence of metabolic diseases has turned them into an escalating global health concern. By producing or altering metabolic products, the gut microbiota plays a pivotal role in maintaining human health and influencing disease development. These metabolites originate from the host itself or the external environment. In the system of interactions between microbes and the host, tryptophan (Trp) plays a central role in metabolic processes. As the amino acid in the human body that must be obtained through dietary intake, it is crucial for various physiological functions. Trp can be metabolized in the gut into three main products: The gut microbiota regulates the transformation of 5-hydroxytryptamine (5-HT, serotonin), kynurenine (Kyn), and various indole derivatives. It has been revealed that a substantial correlation exists between alterations in Trp metabolism and the initiation and progression of metabolic disorders, including obesity, diabetes, non-alcoholic fatty liver disease, and atherosclerosis, but Trp metabolites have not been comprehensively reviewed in metabolic diseases. As such, this review summarizes and analyzes the latest research, emphasizing the importance of further studying Trp metabolism within the gut microbiota to understand and treat metabolic diseases. This carries potential significance for improving human health and may introduce new therapeutic strategies.

Intestinal Microbiota Is a Key Target for Load Swimming to Improve Anxiety Behavior and Muscle Strength in Shank 3-/- Rats

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social disorder and stereotypical behavior, and its incidence rate is increasing yearly. It is considered that acritical period for the prognosis of young children with ASD exists, thus early treatment is crucial. Swimming, due to its comforting effect, is often used to induce enthusiasm in young children for completing activities and has a good effect in the treatment of ASD, but the effective path of swimming has yet to be reported. The intestinal microbiota of ASD patients and animal models has been reported to be different from that of healthy controls, and these changes may affect the brain environment. Therefore, whether the intestinal microbiota is involved in the treatment of ASD by early swimming is our concern. In this study, we used 8-day old Shank3 gene knockout rats with 8 weeks of early load swimming training and conducted behavioral, small intestine morphology, and intestinal content sequencing after training. The results showed that early load swimming significantly reduced the stereotyped and anxious behaviors of Shank3-/- rats, increased their muscle strength, increased the length of intestinal villi and the width of the muscular layer after Shank3 knockout, and affected the abundance of intestinal microorganisms. The abundances with statistical significance were Lactobacillus, Lachnospiraceae, and Alloprevotella. To further confirm the role of intestinal microorganisms in it, we designed a 14-day intestinal stool transplantation experiment. Fecal microbiota transplantation demonstrated that load swimming can significantly reduce the anxiety behavior of Shank3 rats, increase their muscle strength, change the structure of the small intestine, and affect the abundance of intestinal contents. The abundance of Epsilonbateraeota, Prevotella, and Bacteroides significantly changed after transplantation. Our findings confirm the possibility of early load swimming therapy for individuals with ASD and explain that the intestinal microbiota is a key pathway for early exercise therapy for patients with ASD.

Differences in gut microbiota and metabolites between wrestlers with varying precompetition weight control effect

This study intended to analyze the effects of body weight control by the diet, training adaptation, and gut microbiota metabolites of wrestlers in the week leading up to competition. According to the weight difference of wrestlers from the target weight 1 wk before the competition, those whose weight control effectiveness is less than 2 kg were classified as the CW group, whereas more than 2 kg were classified as the CnW group. The body weight, body composition, and diet of wrestlers were recorded; urine samples were taken for standard urine testing, and stool samples were collected for the analysis of gut microbiota and metabolites. The data showed that the relative values of carbohydrate and fat energy in the CnW group were significantly higher than those of the CW group, but the relative values of protein energy were significantly lower. The white blood cells, occult blood, and protein appeared in urine in the CnW group. The microbiota with higher abundance values in the CnW group were positively correlated with the relative value of carbohydrate energy, while the abundance value of Streptococcus was negatively correlated, and the functional prediction of differential bacteria was related to riboflavin and selencompound metabolism. The differential metabolites of CW/CnW group were functionally enriched in the processes of lipid and amino acid metabolism. Overall, the extent of weight control in wrestlers was correlated with sensible dietary patterns, adaptability to training load, and distinct gut microbiota and metabolites.NEW & NOTEWORTHY The purpose of this study is to observe the differences in precompetition diet structure, adaptability to training, gut microbiota, and metabolites of wrestlers with different weight control effects and analyze the correlation between them, aiming to provide scientific guidance and advice on weight control for wrestlers.

Tryptophan Metabolism-Regulating Probiotics Alleviate Hyperuricemia by Protecting the Gut Barrier Integrity and Enhancing Colonic Uric Acid Excretion

The balance of gut microbiota affects uric acid synthesis and excretion, influencing the development of hyperuricemia. This study aimed to investigate the effects and mechanisms of probiotics on hyperuricemia and adenine- and potassium oxonate-induced colonic damage. After two months of gavage at 109 CFU/day, the probiotic strains Lactobacillus rhamnosus UA260 and Lactobacillus plantarum YU28, identified through in vitro screening, significantly reduced serum uric acid levels in hyperuricemia mice from 109.71 ± 56.33 to 38.76 ± 15.06 and 33.22 ± 6.91 μmol/L, respectively. These strains attenuated inflammatory, repaired gut barrier damage, and enhanced colonic uric acid transporter function, thereby promoting uric acid excretion. Furthermore, the probiotics significantly reshaped gut microbiota by increasing the abundance of beneficial bacteria, including Lactobacillus and Coprococcus, while modulating tryptophan, purine, and riboflavin metabolism. Changes in tryptophan metabolites, specifically indole-3-propionic acid and indole-3-acetic acid, were correlated with xanthine oxidase activity, colonic injury, and the expression of the uric acid transporter protein ABCG2 during treatment. Probiotics intervention activated aryl hydrocarbon receptor pathways. These findings suggest that probiotics alleviate hyperuricemia and colonic inflammatory by regulating gut microbiota composition and tryptophan microbial metabolite pathways. Probiotics that modulate tryptophan microbial metabolism may provide a potential strategy for treating or preventing hyperuricemia.

Metabolic regulation of intestinal homeostasis: molecular and cellular mechanisms and diseases

Metabolism serves not only as the organism's energy source but also yields metabolites crucial for maintaining tissue homeostasis and overall health. Intestinal stem cells (ISCs) maintain intestinal homeostasis through continuous self-renewal and differentiation divisions. The intricate relationship between metabolic pathways and intestinal homeostasis underscores their crucial interplay. Metabolic pathways have been shown to directly regulate ISC self-renewal and influence ISC fate decisions under homeostatic conditions, but the cellular and molecular mechanisms remain incompletely understood. Understanding the intricate involvement of various pathways in maintaining intestinal homeostasis holds promise for devising innovative strategies to address intestinal diseases. Here, we provide a comprehensive review of recent advances in the regulation of intestinal homeostasis. We describe the regulation of intestinal homeostasis from multiple perspectives, including the regulation of intestinal epithelial cells, the regulation of the tissue microenvironment, and the key role of nutrient metabolism. We highlight the regulation of intestinal homeostasis and ISC by nutrient metabolism. This review provides a multifaceted perspective on how intestinal homeostasis is regulated and provides ideas for intestinal diseases and repair of intestinal damage.

Influence of α-lipoic acid on longevity and stress resistance in Drosophila melanogaster fed with a high-fat diet

Consumption of a high-fat diet is accompanied by the risks of obesity and early onset of age-associated complications for which dietary interventions are imperative to combat. α-lipoic acid has been shown to hinder diet-induced obesity and induce lifespan-extending efficacy in model organisms. In this study, α-lipoic acid was investigated for its efficacy in improving lifespan and stress resistance in the Canton-S strain of Drosophila melanogaster fed with a high-fat diet. Furthermore, as mating status significantly impacts survival in fruit flies, flies were reared in two experimental groups-group one, in which males and females were bred together, and group two, in which males and females were bred separately. In group one, α-lipoic acid improved the mean lifespan, reduced the fecundity of females, and reduced the mean body weight of flies at a dose range of 2-2.5 mM, respectively. In group two, α-lipoic acid improved the mean lifespan, reduced the fecundity of females, and reduced the mean body weight of flies at a dose range of 1-2.5 mM, respectively. Improved climbing efficiency was observed with α-lipoic acid at the dose range of 1.5-2.5 mM in flies of group one and 1-2.5 mM in flies of group two, respectively. Administration of α-lipoic acid improved resistance to oxidative stress in only female flies of group one at 2.5 mM, whereas in group two, both male and female flies exhibited enhanced resistance to oxidative stress with α-lipoic acid at a dose range of 2-2.5 mM, respectively. Male and female flies of only group one showed improved resistance to heat shock stress with α-lipoic acid at a dose range of 2-2.5 mM. Only female flies of group two exhibited a slight improvement in recovery time following cold shock with α-lipoic acid only at 2.5 mM. No significant change in resistance to starvation stress was observed with any dose of α-lipoic acid in either group of flies. To summarize, data from this study suggested a probable dose and gender-dependent efficacy of α-lipoic acid in flies fed with a high-fat diet, which was significantly influenced by the mating status of flies due to varied rearing conditions.

Melatonin Ameliorates Cadmium-Induced Liver Fibrosis Via Modulating Gut Microbiota and Bile Acid Metabolism

Cadmium (Cd) is a widespread environmental contaminant with high toxicity to human health. Melatonin has been shown to improve Cd-induced liver damage. However, its mechanism has not yet been elucidated. In this study, we aimed to investigate the effects of melatonin on Cd-induced liver damage and fibrosis. A combination of 16S rRNA gene sequencing and mass spectrometry-based metabolomics was adopted to investigate changes in the gut microbiome and its metabolites on the regulation of melatonin in Cd-induced liver injury and fibrosis of mice. Further, nonabsorbable antibiotics, a fecal microbiota transplantation (FMT) program and intestine-specific farnesoid X receptor (FXR) knockout mice were employed to explore the mechanism of melatonin (MT) on liver injury and fibrosis in Cd treated mice. MT significantly improved hepatic inflammation, bile duct hyperplasia, liver damage, and liver fibrosis, with a notable decrease in liver bile acid levels in Cd-exposed mice. MT treatment remodeled the gut microbiota, improved gut barrier function, and reduced the production of gut-derived lipopolysaccharide (LPS). MT significantly decreased the intestinal tauro-β-muricholic acid levels, which are known as FXR antagonists. Notably, MT prominently activated the intestinal FXR signaling, subsequently inhibiting liver bile acid synthesis and decreasing hepatic inflammation in Cd-exposed mice. However, MT could not ameliorate Cd-induced liver damage and fibrosis in Abx-treated mice. Conversely, MT still exerted a protective effect on Cd-induced liver damage and fibrosis in FMT mice. Interestingly, MT failed to reverse liver damage and fibrosis in Cd-exposed intestinal epithelial cell-specific FXR gene knockout mice, indicating that intestinal FXR signaling mediated the protective effect of MT treatment. MT improves Cd-induced liver damage and fibrosis through reshaping the intestinal flora, activating the intestinal FXR-mediated suppression of liver bile acid synthesis and reducing LPS leakage in mice.

Bacterial and clinical metabolic signatures and their interactions in obese patients post-bariatric surgery

BACKGROUND

Obesity is a growing health concern in China, closely linked to metabolic disorders such as type 2 diabetes. Laparoscopic Sleeve Gastrectomy (LSG) is effective in promoting weight loss and improving metabolic outcomes. Emerging evidence highlights the role of gut microbiota in metabolic regulation, yet the specific alterations in gut microbiota and their association with metabolic changes post-surgery in Chinese patients remain unclear. Understanding these shifts could provide key insights into optimizing treatment strategies for metabolic improvement following bariatric surgery.

METHODS

Stool samples and clinical data were collected from 30 obese patients before and 6 months after surgery. The composition of the gut microbiota was analyzed through 16S rRNA sequencing, and Spearman correlation analysis was used to determine the association between gut microbiota and clinical indicators.

RESULTS

The analysis of 30 patients showed a significant decrease in Body Mass Index (BMI) (36.75 ± 4.09 kg/m2 vs 26.37 ± 3.47 kg/m2, p < 0.0001). Glucose metabolism, including Hemoglobin A1C levels, improved significantly (6.05 ± 0.96 vs 5.05 ± 0.25, p < 0.0001), and liver function as well as serum lipid levels were also notably improved. LSG increased the richness and composition of gut microbiota in obese patients post-surgery. These changes in gut microbiota were closely associated with improved clinical metabolic parameters.

CONCLUSION

LSG not only significantly reduces body weight while also alleviating metabolic syndrome and comorbidities by altering gut microbiota.

Indole-3-Acetic Acid Protects Against Lipopolysaccharide-induced Endothelial Cell Dysfunction and Lung Injury through the Activation of USP40

Lung microvascular endothelial cell (EC) dysfunction is the pathological hallmark of acute respiratory distress syndrome. Heat shock protein 90 (HSP90) is a key regulator in control of endothelial barrier disruption and inflammation. Our recent study has demonstrated that ubiquitin-specific peptidase 40 (USP40) preserves endothelial integrity by targeting HSP90β for its deubiquitination and inactivation. Indole-3-acetic acid (IAA), a plant hormone of the auxin class, can also be catabolized from dietary tryptophan by the intestinal microbiota. Accumulating evidence suggests that IAA reduces oxidative stress and inflammation and promotes intestinal barrier function. However, little is known about the role of IAA in endothelial cells and acute lung injury. In this study, we investigated the role of IAA in lung endothelial cell function in the context of acute lung injury. IAA exhibited EC barrier protection against LPS-induced reduction in transendothelial electrical resistance and inflammatory responses. The underlying mechanism of IAA on EC protective effects was investigated by examining the influence of IAA on degrees of HSP90 ubiquitination and USP40 activity. We identified that IAA, acting as a potential activator of USP40, reduces HSP90 ubiquitination, thereby protecting against LPS-induced inflammation in human lung microvascular endothelial cells as well as alleviating experimental lung injury. Furthermore, the EC protective effects of IAA against LPS-induced EC dysfunction and lung injury were abolished in USP40-deficient human lung microvascular endothelial cell and lungs of USP40 EC-specific knockout (USP40cdh5-ECKO) mice. Taken together, this study reveals that IAA protects against LPS-induced EC dysfunction and lung injury through the activation of USP40.

Emerging chemophysiological diversity of gut microbiota metabolites

Human physiology is profoundly influenced by the gut microbiota, which generates a wide array of metabolites. These microbiota-derived compounds serve as signaling molecules, interacting with various cellular targets in the gastrointestinal tract and distant organs, thereby impacting our immune, metabolic, and neurobehavioral systems. Recent advancements have unveiled unique physiological functions of diverse metabolites derived from tryptophan (Trp) and bile acids (BAs). This review highlights the emerging chemophysiological diversity of these metabolites and discusses the role of chemical and biological tools in analyzing and therapeutically manipulating microbial metabolism and host targets, with the aim of bridging the chemical diversity with physiological complexity in host-microbe molecular interactions.

Spatial analysis of murine microbiota and bile acid metabolism during amoxicillin treatment

Antibiotics cause collateral damage to resident microbes that is associated with various health risks. To date, studies have largely focused on the impacts of antibiotics on large intestinal and fecal microbiota. Here, we employ a gastrointestinal (GI) tract-wide integrated multiomic approach to show that amoxicillin (AMX) treatment reduces bacterial abundance, bile salt hydrolase activity, and unconjugated bile acids in the small intestine (SI). Losses of fatty acids (FAs) and increases in acylcarnitines in the large intestine (LI) correspond with spatially distinct expansions of Proteobacteria. Parasutterella excrementihominis engage in FA biosynthesis in the SI, while multiple Klebsiella species employ FA oxidation during expansion in the LI. We subsequently demonstrate that restoration of unconjugated bile acids can mitigate losses of commensals in the LI while also inhibiting the expansion of Proteobacteria during AMX treatment. These results suggest that the depletion of bile acids and lipids may contribute to AMX-induced dysbiosis in the lower GI tract.

Hair Growth Promoting Effects of Solubilized Sturgeon Oil and Its Correlation with the Gut Microbiome

Androgenetic alopecia is a common disease that occurs in both men and women. Several approved medications have been used to treat this condition, but they are associated with certain side effects. Therefore, use of extracts derived from natural products, such as Siberian sturgeon (Acipenser baerii), and the regulation of the gut microbiota have become important topics of research. Sturgeon is known for its high nutritional value and anti-inflammatory properties; however, its effects on androgenetic alopecia and gut microbiota remain uncharacterized. Here, we aimed to investigate whether solubilized sturgeon oil (SSO) promotes hair growth and regulates the gut microbiome. C57BL/6 mice were divided into four groups. Three groups received topical applications of distilled water, SSO, or minoxidil, and one group was orally administered SSO. Each treatment was administered over 4 weeks. Histopathological analysis revealed a significant increase in follicle number (p < 0.001) and follicle diameter (p < 0.05). Immunohistochemical analysis revealed upregulation of β-catenin and ERK-1, markers involved in hair growth-promoting pathways. Furthermore, microbiome analysis revealed that the reduced gut microbiota was negatively correlated with these markers. Our findings indicate that oral administration of SSO promotes hair growth and regulates the abundance of hair growth-promoting gut microbiota.

The Food Additive Benzaldehyde Confers a Broad Antibiotic Tolerance by Modulating Bacterial Metabolism and Inhibiting the Formation of Bacterial Flagella

The rise of antibiotic tolerance in bacteria harboring genetic elements conferring resistance to antibiotics poses an increasing threat to public health. However, the primary factors responsible for the emergence of antibiotic tolerance and the fundamental molecular mechanisms involved remain poorly comprehended. Here, we demonstrate that the commonly utilized food additive Benzaldehyde (BZH) possesses the capacity to induce a significant level of fluoroquinolone tolerance in vitro among resistant Escherichia coli. Our findings from animal models reveal that the pre-administration of BZH results in an ineffective eradication of bacteria through ciprofloxacin treatment, leading to similar survival rates and bacterial loads as observed in the control group. These results strongly indicate that BZH elicits in vivo tolerance. Mechanistic investigations reveal several key factors: BZH inhibits the formation of bacterial flagella and releases proton motive force (PMF), which aids in expelling antibiotics from within cells to reducing their accumulation inside. In addition, BZH suppresses bacterial respiration and inhibits the production of reactive oxygen species (ROS). Moreover, exogenous pyruvate successfully reverses BZH-induced tolerance and restores the effectiveness of antibiotics, highlighting how crucial the pyruvate cycle is in combating antibiotic tolerance. The present findings elucidate the underlying mechanisms of BZH-induced tolerance and highlight potential hazards associated with the utilization of BZH.

Melatonin Protects Against Colistin-Induced Intestinal Inflammation and Microbiota Dysbiosis

Colistin is renowned as a last-resort antibiotic due to the emergence of multidrug-resistant pathogens. However, its potential toxicity significantly hampers its clinical utilization. Melatonin, chemically known as N-acetyl-5-hydroxytryptamine, is an endogenous hormone produced by the pineal gland and possesses diverse biological functions. However, the protective role of melatonin in alleviating antibiotic-induced intestinal inflammation remains unknown. Herein, we reveal that colistin stimulation markedly elevates intestinal inflammatory levels and compromises the gut barrier. In contrast, pretreatment with melatonin safeguards mice against intestinal inflammation and mucosal damage. Microbial diversity analysis indicates that melatonin supplementation prevents a reduction in the abundance of Erysipelotrichales and Bifidobacteriales, as well as an increase in Desulfovibrionales abundance, following colistin exposure. Remarkably, short-chain fatty acids (SCFAs) analysis shows that propanoic acid contributes to the protective effect of melatonin on colistin-induced intestinal inflammation. Furthermore, the protection effects of melatonin and propanoic acid on LPS-induced cellular inflammation in RAW 264.7 cells are confirmed. Mechanistic investigations suggest that intervention with melatonin and propanoic acid can repress the activation of the TLR4 signal and its downstream NF-κB and MAPK signaling pathways, thereby mitigating the toxic effects of colistin. Our work highlights the unappreciated role of melatonin in preventing the potential detrimental effects of colistin on intestinal health and suggests a combined therapeutic strategy to effectively manage intestinal infectious diseases.

Auxin-mediated regulation of susceptibility to toxic metabolites, c-di-GMP levels, and phage infection in the rhizobacterium Serratia plymuthica

The communication between plants and their microbiota is highly dynamic and involves a complex network of signal molecules. Among them, the auxin indole-3-acetic acid (IAA) is a critical phytohormone that not only regulates plant growth and development, but is emerging as an important inter- and intra-kingdom signal that modulates many bacterial processes that are important during interaction with their plant hosts. However, the corresponding signaling cascades remain largely unknown. Here, we advance our understanding of the largely unknown mechanisms by which IAA carries out its regulatory functions in plant-associated bacteria. We showed that IAA caused important changes in the global transcriptome of the rhizobacterium Serratia plymuthica and multidisciplinary approaches revealed that IAA sensing interferes with the signaling mediated by other pivotal plant-derived signals such as amino acids and 4-hydroxybenzoic acid. Exposure to IAA caused large alterations in the transcript levels of genes involved in amino acid metabolism, resulting in significant metabolic alterations. IAA treatment also increased resistance to toxic aromatic compounds through the induction of the AaeXAB pump, which also confers resistance to IAA. Furthermore, IAA promoted motility and severely inhibited biofilm formation; phenotypes that were associated with decreased c-di-GMP levels and capsule production. IAA increased capsule gene expression and enhanced bacterial sensitivity to a capsule-dependent phage. Additionally, IAA induced the expression of several genes involved in antibiotic resistance and led to changes in the susceptibility and responses to antibiotics with different mechanisms of action. Collectively, our study illustrates the complexity of IAA-mediated signaling in plant-associated bacteria.

IMPORTANCE

Signal sensing plays an important role in bacterial adaptation to ecological niches and hosts. This communication appears to be particularly important in plant-associated bacteria since they possess a large number of signal transduction systems that respond to a wide diversity of chemical, physical, and biological stimuli. IAA is emerging as a key inter- and intra-kingdom signal molecule that regulates a variety of bacterial processes. However, despite the extensive knowledge of the IAA-mediated regulatory mechanisms in plants, IAA signaling in bacteria remains largely unknown. Here, we provide insight into the diversity of mechanisms by which IAA regulates primary and secondary metabolism, biofilm formation, motility, antibiotic susceptibility, and phage sensitivity in a biocontrol rhizobacterium. This work has important implications for our understanding of bacterial ecology in plant environments and for the biotechnological and clinical applications of IAA, as well as related molecules.

Carboxymethylated Lycium barbarum seed dreg dietary fiber alleviates high fat diet-induced hyperlipidemia in mice via intestinal regulation

In this study, we investigated the ameliorative gut modulatory effect of carboxymethylated Lycium barbarum seed dreg insoluble dietary fiber (LBSDIDF) on hyperlipidemic mice. After seven weeks of insoluble dietary fiber (IDF) intervention, the results demonstrated that IDFs effectively inhibited body weight gain, with slimming and hypolipidemic effects, and improved liver histopathology by decreasing ALT, AST, TNF-α and IL-6, and increasing short-chain fatty acid (SCFA) levels in hyperlipidemic mice. With the increasing diversity and abundance of intestinal bacteria and decreasing ratio of Firmicutes to Bacteroidetes, intestinal flora facilitated cholesterol lowering effects in hyperlipidemic mice. Our research offers a novel concept for the use of LBSDIDF as a prebiotic to improve intestinal dysbiosis or as a preventive measure against obesity and dyslipidemia.

Preserving the efficacy of antibiotics to tackle antibiotic resistance

Different international agencies recognize that antibiotic resistance is one of the most severe human health problems that humankind is facing. Traditionally, the introduction of new antibiotics solved this problem but various scientific and economic reasons have led to a shortage of novel antibiotics at the pipeline. This situation makes mandatory the implementation of approaches to preserve the efficacy of current antibiotics. The concept is not novel, but the only action taken for such preservation had been the 'prudent' use of antibiotics, trying to reduce the selection pressure by reducing the amount of antibiotics. However, even if antibiotics are used only when needed, this will be insufficient because resistance is the inescapable outcome of antibiotics' use. A deeper understanding of the alterations in the bacterial physiology upon acquisition of resistance and during infection will help to design improved strategies to treat bacterial infections. In this article, we discuss the interconnection between antibiotic resistance (and antibiotic activity) and bacterial metabolism, particularly in vivo, when bacteria are causing infection. We discuss as well how understanding evolutionary trade-offs, as collateral sensitivity, associated with the acquisition of resistance may help to define evolution-based therapeutic strategies to fight antibiotic resistance and to preserve currently used antibiotics.

Vertical Transfer of Maternal Gut Microbes to Offspring of Western Diet-Fed Dams Drives Reduced Levels of Tryptophan Metabolites and Postnatal Innate Immune Response

Maternal obesity and/or Western diet (WD) is associated with an increased risk of metabolic dysfunction-associated steatotic liver disease (MASLD) in offspring, driven, in part, by the dysregulation of the early life microbiome. Here, using a mouse model of WD-induced maternal obesity, we demonstrate that exposure to a disordered microbiome from WD-fed dams suppressed circulating levels of endogenous ligands of the aryl hydrocarbon receptor (AHR; indole, indole-3-acetate) and TMAO (a product of AHR-mediated transcription), as well as hepatic expression of Il10 (an AHR target), in offspring at 3 weeks of age. This signature was recapitulated by fecal microbial transfer from WD-fed pregnant dams to chow-fed germ-free (GF) lactating dams following parturition and was associated with a reduced abundance of Lactobacillus in GF offspring. Further, the expression of Il10 was downregulated in liver myeloid cells and in LPS-stimulated bone marrow-derived macrophages (BMDM) in adult offspring, suggestive of a hypo-responsive, or tolerant, innate immune response. BMDMs from adult mice lacking AHR in macrophages exhibited a similar tolerogenic response, including diminished expression of Il10. Overall, our study shows that exposure to maternal WD alters microbial metabolites in the offspring that affect AHR signaling, potentially contributing to innate immune hypo-responsiveness and progression of MASLD, highlighting the impact of early life gut dysbiosis on offspring metabolism. Further investigations are warranted to elucidate the complex interplay between maternal diet, gut microbial function, and the development of neonatal innate immune tolerance and potential therapeutic interventions targeting these pathways.

Transfer learning predicts species-specific drug interactions in emerging pathogens

Machine learning (ML) algorithms are necessary to efficiently identify potent drug combinations within a large candidate space to combat drug resistance. However, existing ML approaches cannot be applied to emerging and under-studied pathogens with limited training data. To address this, we developed a transfer learning and crowdsourcing framework (TACTIC) to train ML models on data from multiple bacteria. TACTIC was built using 2,965 drug interactions from 12 bacterial strains and outperformed traditional ML models in predicting drug interaction outcomes for species that lack training data. Top TACTIC model features revealed genetic and metabolic factors that influence cross-species and species-specific drug interaction outcomes. Upon analyzing ~600,000 predicted drug interactions across 9 metabolic environments and 18 bacterial strains, we identified a small set of drug interactions that are selectively synergistic against Gram-negative (e.g., A. baumannii) and non-tuberculous mycobacteria (NTM) pathogens. We experimentally validated synergistic drug combinations containing clarithromycin, ampicillin, and mecillinam against M. abscessus, an emerging pathogen with growing levels of antibiotic resistance. Lastly, we leveraged TACTIC to propose selectively synergistic drug combinations to treat bacterial eye infections (endophthalmitis).

The causal role of gut microbiota in susceptibility of Long COVID: a Mendelian randomization study

Background

Long COVID is a major challenge facing the public. Gut microbiota is closely related to Long COVID. However, the causal effects between gut microbiota and Long COVID remains unclear.

Methods

Using summary statistics from Genome-Wide Association Studies (GWAS), Mendelian randomization (MR) analyses were performed to investigate the relationship between gut microbiota and Long COVID. The primary statistical method employed was Inverse Variance Weighted (IVW). Sensitivity analyses were then conducted to evaluate the reliability of the findings and account for potential confounding variables. Finally, a reverse MR analysis was conducted to examine potential associations between Long COVID and genetically predicted gut microbiota compositions.

Results

There were 2 positive and 1 negative causal effect between gut microbiota and Long COVID. Meta-analysis results show that genus Parasutterella (OR = 1.145, 95%CI = 1.035 ∼ 1.266, P = 0.008) and genus Oscillospira (OR = 1.425, 95%CI = 1.235 ∼ 1.645, P < 0.001) significantly increased the risk of Long COVID. And genus Eisenbergiella (OR = 0.861, 95%CI = 0.785 ∼ 0.943, P = 0.001) significantly decreased the risk of Long COVID. Neither the pleiotropy nor the heterogeneity was observed. Reverse causal effect does not hold.

Conclusion

Our research has provided genetic evidence that establishes multiple causal relationships between the gut microbiota and Long COVID, supporting the role of the gut microbiota in Long COVID. It is possible that different taxa play a role in the development of Long COVID. The causal relationships identified in this study require further investigation.

Propolis Alleviates Acute Lung Injury Induced by Heat-Inactivated Methicillin-Resistant Staphylococcus aureus via Regulating Inflammatory Mediators, Gut Microbiota and Serum Metabolites

Propolis has potential anti-inflammatory properties, but little is known about its efficacy against inflammatory reactions caused by drug-resistant bacteria, and the difference in efficacy between propolis and tree gum is also unclear. Here, an in vivo study was performed to study the effects of ethanol extract from poplar propolis (EEP) and poplar tree gum (EEG) against heat-inactivated methicillin-resistant Staphylococcus aureus (MRSA)-induced acute lung injury (ALI) in mice. Pre-treatment with EEP and EEG (100 mg/kg, p.o.) resulted in significant protective effects on ALI in mice, and EEP exerted stronger activity to alleviate lung tissue lesions and ALI scores compared with that of EEG. Furthermore, EEP significantly suppressed the levels of pro-inflammatory mediators in the lung, including TNF-α, IL-1β, IL-6, and IFN-γ. Gut microbiota analysis revealed that both EEP and EEG could modulate the composition of the gut microbiota, enhance the abundance of beneficial microbiota and reduce the harmful ones, and partly restore the levels of short-chain fatty acids. EEP could modulate more serum metabolites and showed a more robust correlation between serum metabolites and gut microbiota. Overall, these results support the anti-inflammatory effects of propolis in the treatment of ALI, and the necessity of the quality control of propolis.

Evaluation of Physicochemical Properties and Prebiotics Function of a Bioactive Pleurotus eryngii Aqueous Extract Powder Obtained by Spray Drying

A bioactive Pleurotus eryngii aqueous extract powder (SPAE) was obtained by spray drying and its performance in terms of physicochemical properties, in vitro digestion, inflammatory factors, and modulation of the intestinal microbiota was explored. The results indicated that the SPAE exhibited a more uniform particle size distribution than P. eryngii polysaccharide (PEP). Meanwhile, a typical absorption peak observed at 843 cm-1 in the SPAE FTIR spectra indicated the existence of α-glycosidic bonds. SPAE exhibited higher antioxidant abilities and superior resistance to digestion in vitro. In addition, SPAE supplementation to mice significantly reduced the release of factors that promote inflammation, enhanced the secretion of anti-inflammatory factors, and sustained maximum production of short-chain fatty acids (SCFAs). Additionally, it significantly enhanced the relative abundance of SCFAs-producing Akkermansia and reduced the abundance of Ruminococcus and Clostridiides in intestines of mice. These results show the potential of SPAE as a novel material with prebiotic effects for the food and pharmaceutical industries.

In-depth multiomic characterization of the effects of obesity in high-fat diet-fed mice

High-fat diet (HFD)-fed mice have been widely used in the clinical investigation of obesity. However, the long-term effect of HFD on gut microbiota and metabolites, plasma and liver metabolomics, colonic and liver transcriptomics remain largely unknown. In this study, 6-week-old C57BL/6J male mice fed with HFD for 14 weeks showed increased obesity-related indexes including alanine aminotransferase, aspartate aminotransferase, total cholesterol, total triglyceride, free fatty acids, lipopolysaccharides, IL-6, and TNFα. Furthermore, microbial diversity and richness were also significantly decreased. In the colon, genes involved in tryptophan metabolism, PPAR signaling pathway, cholesterol metabolism, and lipid localization and transport, were upregulated. While in the liver, MAPK signaling and unsaturated fatty acid biosynthesis were upregulated. Metabolomic analyses revealed decreased levels of glycerophospholipids and fatty acyl, but increased amino acids, coenzymes and vitamins, and organic acids in the colon, suggesting high absorption of oxidized lipids, while acyl-carnitine, lysophosphatidylcholine, lysophosphatidylethanolamine, and oxidized lipids were reduced in the liver, suggesting a more active lipid metabolism. Finally, correlation analyses revealed a positive correlation between gut microbiota and metabolites and the expression of genes associated with lipid localization, absorption, and transport in the colon, and nutrients and energy metabolism in the liver. Taken together, our results provide a comprehensive characterization of long-term HFD-induced obesity in mice.

Exopolysaccharides and Surface-Layer Proteins Expressed by Biofilm-State Lactiplantibacillus plantarum Y42 Play Crucial Role in Preventing Intestinal Barrier and Immunity Dysfunction of Balb/C Mice Infected by Listeria monocytogenes ATCC 19115

Our previous study showed that Lactiplantibacillus plantarum Y42 in the biofilm state can produce more exopolysaccharides and surface-layer proteins and showed a stronger promoting effect on intestinal barrier function than that in the planktonic state. In this study, oral administration of the live/pasteurized planktonic or biofilm L. plantarum Y42 and its metabolites (exopolysaccharides and surface-layer proteins) increased the expression of Occludin, Claudin-1, ZO-1, and MUC2 in the gut of the Balb/C mice after exposure to Listeria monocytogenes ATCC 19115 and inhibited the activation of the NLRP3 inflammasome pathway, which in turn reduced the levels of inflammatory cytokines IL-1β and IL-18 in the serum of the mice. Furthermore, oral administration of the live/pasteurized planktonic or biofilm L. plantarum Y42 and its metabolites increased the abundance of beneficial bacteria (e.g., Lachnospiraceae_NK4A136_group and Prevotellaceae_UCG-001) while reducing the abundance of harmful bacteria (e.g., norank_f__Muribaculaceae) in the gut of the mice, in line with the increase of short-chain fatty acids and indole derivatives in the feces of the mice. Notably, biofilm L. plantarum Y42 exerted a better preventing effect on the intestinal barrier dysfunction of the Balb/C mice due to the fact that biofilm L. plantarumY42 expressed more exopolysaccharides and surface-layer proteins than the planktonic state. These results provide data support for the use of exopolysaccharides and surface-layer proteins extracted from biofilm-state L. plantarum Y42 as functional food ingredients in preventing intestinal barrier dysfunction.

Microbial Indoles: Key Regulators of Organ Growth and Metabolic Function

Gut microbes supporting body growth are known but the mechanisms are less well documented. Using the microbial tryptophan metabolite indole, known to regulate prokaryotic cell division and metabolic stress conditions, we mono-colonized germ-free (GF) mice with indole-producing wild-type Escherichia coli (E. coli) or tryptophanase-encoding tnaA knockout mutant indole-non-producing E. coli. Indole mutant E. coli mice showed multiorgan growth retardation and lower levels of glycogen, cholesterol, triglycerides, and glucose, resulting in an energy deficiency despite increased food intake. Detailed analysis revealed a malfunctioning intestine, enlarged cecum, and reduced numbers of enterochromaffin cells, correlating with a metabolic phenotype consisting of impaired gut motility, diminished digestion, and lower energy harvest. Furthermore, indole mutant mice displayed reduction in serum levels of tricarboxylic acid (TCA) cycle intermediates and lipids. In stark contrast, a massive increase in serum melatonin was observed-frequently associated with accelerated oxidative stress and mitochondrial dysfunction. This observational report discloses functional roles of microbe-derived indoles regulating multiple organ functions and extends our previous report of indole-linked regulation of adult neurogenesis. Since indoles decline by age, these results imply a correlation with age-linked organ decline and levels of indoles. Interestingly, increased levels of indole-3-acetic acid, a known indole metabolite, have been shown to correlate with younger biological age, further supporting a link between biological age and levels of microbe-derived indole metabolites. The results presented in this resource paper will be useful for the future design of food intervention studies to reduce accelerated age-linked organ decline.

Gut microbiome-metabolites axis: A friend or foe to colorectal cancer progression

An expanding corpus of research robustly substantiates the complex interrelation between gut microbiota and the onset, progression, and metastasis of colorectal cancer. Investigations in both animal models and human subjects have consistently underscored the role of gut bacteria in a variety of metabolic activities, driven by dietary intake. These activities include amino acid metabolism, carbohydrate fermentation, and the generation and regulation of bile acids. These metabolic derivatives, in turn, have been identified as significant contributors to the progression of colorectal cancer. This thorough review meticulously explores the dynamic interaction between gut bacteria and metabolites derived from the breakdown of amino acids, fatty acid metabolism, and bile acid synthesis. Notably, bile acids have been recognized for their potential carcinogenic properties, which may expedite tumor development. Extensive research has revealed a reciprocal influence of gut microbiota on the intricate spectrum of colorectal cancer pathologies. Furthermore, strategies to modulate gut microbiota, such as dietary modifications or probiotic supplementation, may offer promising avenues for both the prevention and adjunctive treatment of colorectal cancer. Nevertheless, additional research is imperative to corroborate these findings and enhance our comprehension of the underlying mechanisms in colorectal cancer development.

DMT1-mediated iron overload accelerates cartilage degeneration in Hemophilic Arthropathy through the mtDNA-cGAS-STING axis

INTRODUCTION

Excess iron contributes to Hemophilic Arthropathy (HA) development. Divalent metal transporter 1 (DMT1) delivers iron into the cytoplasm, thus regulating iron homeostasis.

OBJECTIVES

We aimed to investigate whether DMT1-mediated iron homeostasis is involved in bleeding-induced cartilage degeneration and the molecular mechanisms underlying iron overload-induced chondrocyte damage.

METHODS

This study established an in vivo HA model by puncturing knee joints of coagulation factor VIII gene knockout mice with a needle, and mimicked iron overload conditions in vitro by treatment of Ferric ammonium citrate (FAC).

RESULTS

We demonstrated that blood exposure caused iron overload and cartilage degeneration, as well as elevated expression of DMT1. Furthermore, DMT1 silencing alleviated blood-induced iron overload and cartilage degeneration. In hemophilic mice, articular cartilage degeneration was also suppressed by intro-articularly injection of DMT1 adeno-associated virus 9 (AAV9). Mechanistically, RNA-sequencing analysis indicated the association between iron overload and cGAS-STING pathway. Further, iron overload triggered mtDNA-cGAS-STING pathway activation, which could be effectively mitigated by DMT1 silencing. Additionally, we discovered that RU.521, a potent Cyclic GMP-AMP Synthase (cGAS) inhibitor, successfully suppressed the downward cascades of cGAS-STING, thereby protecting against chondrocyte damage.

CONCLUSION

Taken together, DMT1-mediated iron overload promotes chondrocyte damage and murine HA development, and targeted DMT1 may provide therapeutic and preventive approaches in HA.

Lipid Metabolites as Potential Regulators of the Antibiotic Resistome in Tetramorium caespitum

Antibiotic resistance genes (ARGs) are ancient but have become a modern critical threat to health. Gut microbiota, a dynamic reservoir for ARGs, transfer resistance between individuals. Surveillance of the antibiotic resistome in the gut during different host growth phases is critical to understanding the dynamics of the resistome in this ecosystem. Herein, we disentangled the ARG profiles and the dynamic mechanism of ARGs in the egg and adult phases of Tetramorium caespitum. Experimental results showed a remarkable difference in both gut microbiota and gut resistome with the development of T. caespitum. Meta-based metagenomic results of gut microbiota indicated the generalizability of gut antibiotic resistome dynamics during host development. By using Raman spectroscopy and metabolomics, the metabolic phenotype and metabolites indicated that the biotic phase significantly changed lipid metabolism as T. caespitum aged. Lipid metabolites were demonstrated as the main factor driving the enrichment of ARGs in T. caespitum. Cuminaldehyde, the antibacterial lipid metabolite that displayed a remarkable increase in the adult phase, was demonstrated to strongly induce ARG abundance. Our findings show that the gut resistome is host developmental stage-dependent and likely modulated by metabolites, offering novel insights into possible steps to reduce ARG dissemination in the soil food chain.

Transfer and accumulation of antibiotic resistance genes and bacterial pathogens in the mice gut due to consumption of organic foods

Over the last few decades, organic food demand has grown largely because of increasing personal health concerns. Organic farming introduces antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) into foods. However, potential effects of organic foods on the gut microbiome and ARGs have been overlooked. Using high-throughput quantitative PCR and 16S rRNA high-throughput sequencing technology, we examined 132 ARGs from major classes, eight transposase genes, universal class I integron-integrase gene (intI), clinical class I integron-integrase gene (cintI), and the bacterial community in mouse gut after 8 weeks with an either organic or inorganic lettuce and wheat diet. A total of 8 types of major ARGs and 10 mobile genetic elements (MGEs) were detected in mice gut, including tetracycline, multidrug, sulfonamide, aminoglycoside, beta-lactamase, chloramphenicol, MLSB and vancomycin resistance genes. We found that abundance and diversity of ARGs, mobile gene elements, and potential ARB in the gut increased with time after consumption of organic foods, whereas no significant changes were observed in inorganic treated groups. Moreover, MGEs, including IS613, Tp614 and tnpA_03 were found to play an important role in regulating ARG profiles in the gut microbiome following consumption of organic foods. Importantly, feeding organic food increased the relative abundance of the potentially antibiotic-resistant pathogens, Bacteroides and Streptococcus. Our results confirm that there is an increasing risk of ARGs and ARB in the gut microbiome, which highlights the importance of organic food industries taking into account the potential accumulation and transmission of ARGs as a risk factor.

Psychological stress-induced microbial metabolite indole-3-acetate disrupts intestinal cell lineage commitment

The brain and gut are intricately connected and respond to various stimuli. Stress-induced brain-gut communication is implicated in the pathogenesis and relapse of gut disorders. The mechanism that relays psychological stress to the intestinal epithelium, resulting in maladaptation, remains poorly understood. Here, we describe a stress-responsive brain-to-gut metabolic axis that impairs intestinal stem cell (ISC) lineage commitment. Psychological stress-triggered sympathetic output enriches gut commensal Lactobacillus murinus, increasing the production of indole-3-acetate (IAA), which contributes to a transferrable loss of intestinal secretory cells. Bacterial IAA disrupts ISC mitochondrial bioenergetics and thereby prevents secretory lineage commitment in a cell-intrinsic manner. Oral α-ketoglutarate supplementation bolsters ISC differentiation and confers resilience to stress-triggered intestinal epithelial injury. We confirm that fecal IAA is higher in patients with mental distress and is correlated with gut dysfunction. These findings uncover a microbe-mediated brain-gut pathway that could be therapeutically targeted for stress-driven gut-brain comorbidities.

The synbiotic combination of probiotics and inulin improves NAFLD though modulating gut microbiota

Prebiotics can promote the growth of probiotics, cocombine of these is called synbiotics, and synbiotics is powerful regulators of gut microbiota. Intestinal microbiota plays an important role in nonalcoholic fatty liver disease (NAFLD), so synbiotics could be a therapeutic alternative. This study aims to investigate the effect of synbiotics combination of probiotics (Streptococcus Bifidobacterium and Streptococcus thermophilus) and prebiotics (Inulin) in vivo model of early NAFLD using yogurt as carrier. The results demonstrate that the yogurt with synbiotics combination group (HS) improves the biochemical indicators related to total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and insulin resistance (IR) in mice (P< .01). HS improves the development of lipid metabolism and inflammation by activating the AMPK and NFκB signaling pathway. In addition, HS restores the intestinal barrier dysfunction and inflammation caused by a high-fat diet. The 16S rRNA demonstrates that the gut microbiota composition of mice treated with HS is significantly altered specifically, the Firmicutes/Bacteroidetes ratio is significantly lower than in HFD-fed mice (P< .01). Our findings suggest the applicability of HS in preventing obesity-related NAFLD via its antioxidant, anti-inflammatory, and improved lipid metabolism by the gut-liver axis and provide a solid theoretical foundation for developing prebiotics for the prevention of NAFLD.