Lactobacillus reuteri J1 prevents obesity by altering the gut microbiota and regulating bile acid metabolism in obese mice

Regulation of bile acids and their receptor FXR in metabolic diseases

High sugar, high-fat diets and unhealthy lifestyles have led to an epidemic of obesity and obesity-related metabolic diseases, seriously placing a huge burden on socio-economic development. A deeper understanding and elucidation of the specific molecular biological mechanisms underlying the onset and development of obesity has become a key to the treatment of metabolic diseases. Recent studies have shown that the changes of bile acid composition are closely linked to the development of metabolic diseases. Bile acids can not only emulsify lipids in the intestine and promote lipid absorption, but also act as signaling molecules that play an indispensable role in regulating bile acid homeostasis, energy expenditure, glucose and lipid metabolism, immunity. Disorders of bile acid metabolism are therefore important risk factors for metabolic diseases. The farnesol X receptor, a member of the nuclear receptor family, is abundantly expressed in liver and intestinal tissues. Bile acids act as endogenous ligands for the farnesol X receptor, and erroneous FXR signaling triggered by bile acid dysregulation contributes to metabolic diseases, including obesity, non-alcoholic fatty liver disease and diabetes. Activation of FXR signaling can reduce lipogenesis and inhibit gluconeogenesis to alleviate metabolic diseases. It has been found that intestinal FXR can regulate hepatic FXR in an organ-wide manner. The crosstalk between intestinal FXR and hepatic FXR provides a new idea for the treatment of metabolic diseases. This review focuses on the relationship between bile acids and metabolic diseases and the current research progress to provide a theoretical basis for further research and clinical applications.

Phosphatidylcholine ameliorates lipid accumulation and liver injury in high-fat diet mice by modulating bile acid metabolism and gut microbiota

Phosphatidylcholine (PC) has garnered considerable attention due to its involvement in a wide array of crucial biological functions. However, there is still much to active explore regarding the precise mechanisms that underlie PC's actions in the context of high-fat diet. In this study, we found that both PC intervention and treatment significantly mitigated lipid accumulation, liver damage, and body weight gaining triggered by the high-fat diet. Untargeted and targeted metabolomic analyses uncovered substantial effects of PC on bile acid metabolism, especially led to a substantial reduction in elevated levels of free bile acids. 16S rRNA gene sequencing revealed that PC modulated the gut microbiota structures and compositions in high-fat diet mice, particularly exhibiting a positive association with Pseudoflavonifractor abundance, and a negative correlation with Olsenella, Parasutterella, and Allobaculum abundance. Our study suggested that PC held promise as a potential candidate for alleviating lipid metabolism injury, liver disease or obesity.

Edible fungi polysaccharides modulate gut microbiota and lipid metabolism: A review

Edible fungi polysaccharides (EFPs) and gut microbiota (GM) play an important role in lipid metabolism. The structure of GM is complex and can be dynamically affected by the diet. EFPs can be used as dietary intervention to improve lipid metabolism directly, or by regulate the GM to participate in the host lipid metabolism by a complex mechanism. In this paper, we reviewed that EFPs regulate the balance of GM by increasing the number of beneficial bacteria and decreasing the number of harmful bacteria in the intestinal tract. The metabolites of GM are mainly bile acids (BAs), short-chain fatty acids (SCFAs), and lipopolysaccharides (LPS). EFPs can promote the synthesis of BAs and increase the content of SCFAs that produced by GM fermented EFPs, but reduce the content of LPS to regulate lipid metabolism. This review provides a valuable reference for further elucidation of the relationship between EFPs-GM-lipid metabolism and EFPs targeted regulation of GM to improve public health.

Effect of synbiotic supplementation on obesity and gut microbiota in obese adults: a double-blind randomized controlled trial

Background

Synbiotics, combining specific probiotics and selected prebiotics, may benefit health issues like obesity, but evidence remains inconsistent.

Objective

This study aimed to verify the effect of a pre-screened synbiotics combination [containing Bifidobacterium animalis subsp. lactis MN-Gup (MN-Gup), galacto-oligosaccharides (GOS) and xylo-oligosaccharides (XOS)] on obesity in the population.

Methods

In a randomized, double-blind, placebo-controlled trial, 80 individuals with obesity consumed daily synbiotics (containing MN-Gup 1 × 1011 CFU/day, GOS 0.7 g/day, and XOS 0.7 g/day) or placebo for 12 weeks. Body composition, blood lipids, serum hormone, bile acids, and gut microbiota were measured pre-and post-intervention.

Results

Synbiotics supplementation significantly decreased body fat percentage, waist, and serum low-density lipoprotein cholesterol (LDL-C), increased peptide YY, cholecystokinin, oxyntomodulin, GSH (glutathione peroxidase) in individuals with obesity. Additionally, synbiotic supplementation led to an enrichment of beneficial bacteria and bile acids chenodeoxycholic acid (CDCA). Bifidobacterium and Romboutsia were significantly positively correlated with CDCA. A more favorable effect was observed in individuals with obesity and abnormal LDL-C compared to those without dyslipidemia.

Conclusion

Twelve-week synbiotics intervention reduced body fat percentage, waist, and serum LDL-C, especially in individuals with obesity and abnormal LDL-C. The possible mechanisms may be related to changes in gut microbiota, bile acids and gut hormones.

Clinical trial registration

Chictr.org.cn, identifier ChiCTR2200064156.

The potential mechanism of action of gut flora and bile acids through the TGR5/TRPV1 signaling pathway in diabetic peripheral neuropathic pain

Diabetic peripheral neuropathic pain (DPNP) is a major complication of diabetes that markedly affects the quality of life and health status of patients. Recent studies have investigated the potential regulatory influence of gut flora and bile acids on DPNP via the TGR5/TRPV1 signaling pathway. Dysbiosis of the gut flora not only directly affects bile acid metabolism but also significantly correlates with diabetes-associated neuropathy through interactions with the bile acid receptor TGR5 and the ion channel TRPV1. This review describes how alterations in the gut flora and bile acid metabolism contribute to the pathogenesis of DPNP through the TGR5/TRPV1 signaling pathway, revealing potential applications for this pathway in DPNP management. Furthermore, experimental and clinical studies have demonstrated the modulation of gut flora and bile acid metabolism as well as targeting the TGR5/TRPV1 signaling pathway as an innovative therapeutic approach. Further studies are warranted to elucidate the underlying mechanism and develop treatment modalities based on gut flora regulation and signaling pathway interventions, thus providing novel insights and approaches for DPNP therapy.

Lacticaseibacillus plantarum postbiotics prepared by the combined technique of pasteurization and ultrasound: effective measures to alleviate obesity based on the SCFAs-GPR41/GPR43 signaling pathway

Postbiotics have recently garnered substantial research attention, especially in obesity research. In this study, upon comparing the proliferative effects of three food-derived media-skim milk, soy milk, and almond milk-on Lactiplantibacillus plantarum J26 (L. plantarum J26), skim milk was found to be the most effective. The metabolomic analysis further unveiled that the metabolites produced by the strain cultured in skim milk influenced the greatest number of lipid metabolism-associated pathways. Additionally, to better preserve heat-sensitive substances, ultrasound and pasteurization were combined and used here for inactivation. L. plantarum J26 postbiotics, prepared through pasteurization combined with 400 W ultrasound treatment for 30 min, exhibited the most effectiveness at inhibiting cellular triglyceride accumulation, reducing its level to 0.99 mg per 104 CFU. The prepared postbiotics significantly reduced the increase in multiple indicators, including body weight, blood lipids, and adipokines in obese mice (p < 0.05). Following treatment, liver tissue damage as well as white and brown adipose tissue damage were also markedly improved in obese mice. According to gut microbiota sequencing, the postbiotic intervention increased Lactobacillus and Bifidobacterium abundances but reduced the abundances of obesity-associated Faecalibacterium and Erysipelotrichaceae. Additionally, the postbiotics elevated the acetate, propionate, and butyrate levels by 14.95%, 23.89%, and 8.31%, respectively. High postbiotic doses significantly upregulated the expression of GPR41/GPR43, short-chain fatty acid (SCFA) receptor genes, in the liver and adipose tissues (p < 0.05), thus correcting the obesity-induced anomalies in the SCFAs-GPR41/GPR43 signaling pathway. This research offers compelling evidence supporting the use of edible postbiotics in targeted obesity regulation.

The Novel Insight of Gut Microbiota from Mouse Model to Clinical Patients and the Role of NF-κB Pathway in Polycystic Ovary Syndrome

Polycystic Ovary Syndrome (PCOS) is a metabolic disorder characterized by hyperandrogenism and related symptoms in women of reproductive age. Emerging evidence suggests that chronic low-grade inflammation plays a significant role in the development of PCOS. The gut microbiota, a complex bacterial ecosystem, has been extensively studied for various diseases, including PCOS, while the underlying mechanisms are not fully understood. This review comprehensively summarizes the changes in gut microbiota and metabolites observed in PCOS and their potential association with the condition. Additionally, we discuss the role of abnormal nuclear factor κB signaling in the pathogenesis of PCOS. These findings offer valuable insights into the mechanisms of PCOS and may pave the way for the development of control and therapeutic strategies for this condition in clinical practice. By bridging the gap between mouse models and clinical patients, this review contributes to a better understanding of the interplay between gut microbiota and inflammation in PCOS, thus paving new ways for future investigations and interventions.

Amelioration impact of gut-brain communication on obesity control by regulating gut microbiota composition through the ingestion of animal-plant-derived peptides and dietary fiber: can food reward effect as a hidden regulator?

Various roles of intestinal flora in the gut-brain axis response pathway have received enormous attention because of their unique position in intestinal flora-derived metabolites regulating hormones, inducing appetite, and modulating energy metabolism. Reward pathways in the brain play a crucial role in gut-brain communications, but the mechanisms have not been methodically understood. This review outlined the mechanisms by which leptin, ghrelin, and insulin are influenced by intestinal flora-derived metabolites to regulate appetite and body weight, focused on the significance of the paraventricular nucleus and ventromedial prefrontal cortex in food reward. The vagus nerve and mitochondria are essential pathways of the intestinal flora involved in the modulation of neurotransmitters, neural signaling, and neurotransmission in gut-brain communications. The dynamic response to nutrient intake and changes in the characteristics of feeding activity requires the participation of the vagus nerve to transmit messages to be completed. SCFAs, Bas, BCAAs, and induced hormones mediate the sensory information and reward signaling of the host in the complex regulatory mechanism of food selection, and the composition of the intestinal flora significantly impacts this process. Food reward in the process of obesity based on gut-brain communications expands new ideas for the prevention and treatment of obesity.

Polysaccharide extracted from Atractylodes macrocephala improves the spleen deficiency constipation in mice by regulating the gut microbiota to affect the 5-HT synthesis

BACKGROUND

The traditional herbal medicine Atractylodes macrocephala Koidz. (A. macrocephala) is commonly utilized for alleviating symptoms associated with spleen deficiency, abdominal distension, diarrhea, and constipation. These pharmacological effects are attributed to a variety of active constituents. However, the specific bioactive compounds responsible for promoting defecation and gastrointestinal transit in A. macrocephala remain unidentified.

METHODS

The primary polysaccharide characteristics of PAMK was elucidated by HPLC, FT-IR, and HGPGC. Efficacy of PAMK (0.07, 0.14, and 0.28 mg/g) on mice was evaluated in a spleen deficiency constipation mouse model by analyzing stool parameters, constipation-related physiological indexes, and SCFAs. The expression levels of 5-HT3R, 5-HT4R, and related receptor genes were examined by RT-qPCR, and neurotransmitters were examined using ELISA. Finally, the diversity of gut microbiota was analyzed with 16S rDNA sequencing.

KEY RESULTS

The results showed that PAMK significantly reduced the gastrointestinal transport time and increased the number of fecal pellets and fecal water content in spleen deficiency constipation model mice. PAMK kept the balance of 5-HT, SCFAs, TPH-1, SERT, CgA, and neurotransmitter levels (VIP, SP, MTL) in mice colon. In addition, PAMK could regulate the abundance of gut microbiota such as Alistopes, Bacteroides, and Odoribacter in spleen deficiency constipation model mice gut.

CONCLUSIONS AND INFERENCES

It can be concluded that PAMK effectively ameliorated the symptoms of spleen deficiency constipation in mice by modulating the expression of 5-HT and its associated receptors. The underlying mechanism was elucidated, providing a solid theoretical foundation for the therapeutic application of A. macrocephala in treating spleen deficiency constipation and offering potential for developing novel approaches to address this condition.

Detection of H1N1 Influenza Virus in the Bile of a Severe Influenza Mouse Model

AIMS

Influenza virus infection may lead to fatal complications including multi-organ failure and sepsis. The influenza virus was detected in various extra-pulmonary organs in autopsy studies during the 2009 pandemic. However, limited research has been conducted on the presence of viral particle or viral components in the peripheral blood.

METHODS AND RESULTS

We established a mouse model for severe H1N1 influenza. The bile and blood samples were collected over time and inoculated into embryonated chicken eggs. We detected live influenza virus in bile and blood samples in early infection. Immunofluorescence showed influenza viral components in the liver tissue. No live virus was isolated in the bile in mice intragastrically administered with influenza virus, indicating that the virus was spread from the blood stream. Targeted metabolomics analysis of bile acid and liver tissues showed that a secondary bile acid (3-dehydrocholic acid) was decreased after influenza H1N1 infection. Genes related with fatty acid metabolism and bile secretion pathways were down-regulated in liver after influenza virus infection.

CONCLUSION

Our study indicated that influenza virus viremia is present in severe influenza, and that the liver is a target organ for influenza viral sepsis.

Hepatic protein phosphatase 1 regulatory subunit 3G alleviates obesity and liver steatosis by regulating the gut microbiota and bile acid metabolism

Intestinal dysbiosis and disrupted bile acid (BA) homeostasis are associated with obesity, but the precise mechanisms remain insufficiently explored. Hepatic protein phosphatase 1 regulatory subunit 3G (PPP1R3G) plays a pivotal role in regulating glycolipid metabolism; nevertheless, its obesity-combatting potency remains unclear. In this study, a substantial reduction was observed in serum PPP1R3G levels in high-body mass index (BMI) and high-fat diet (HFD)-exposed mice, establishing a positive correlation between PPP1R3G and non-12α-hydroxylated (non-12-OH) BA content. Additionally, hepatocyte-specific overexpression of Ppp1r3g (PPP1R3G HOE) mitigated HFD-induced obesity as evidenced by reduced weight, fat mass, and an improved serum lipid profile; hepatic steatosis alleviation was confirmed by normalized liver enzymes and histology. PPP1R3G HOE considerably impacted systemic BA homeostasis, which notably increased the non-12-OH BAs ratio, particularly lithocholic acid (LCA). 16S ribosomal DNA (16S rDNA) sequencing assay indicated that PPP1R3G HOE reversed HFD-induced gut dysbiosis by reducing the Firmicutes/Bacteroidetes ratio and Lactobacillus population, and elevating the relative abundance of Blautia, which exhibited a positive correlation with serum LCA levels. A fecal microbiome transplantation test confirmed that the anti-obesity effect of hepatic PPP1R3G was gut microbiota-dependent. Mechanistically, PPP1R3G HOE markedly suppressed hepatic cholesterol 7α-hydroxylase (CYP7A1) and sterol-12α-hydroxylase (CYP8B1), and concurrently upregulated oxysterol 7-α hydroxylase and G protein-coupled BA receptor 5 (TGR5) expression under HFD conditions. Furthermore, LCA administration significantly mitigated the HFD-induced obesity phenotype and elevated non-12-OH BA levels. These findings emphasize the significance of hepatic PPP1R3G in ameliorating diet-induced adiposity and hepatic steatosis through the gut microbiota-BA axis, which may serve as potential therapeutic targets for obesity-related disorders.

Current research progress, opportunities, and challenges of Limosillactobacillus reuteri-based probiotic dietary strategies

Limosillactobacillus reuteri (L. reuteri), a type of Lactobacillus spp., stands out as the most extensively researched probiotic. Its remarkable intestinal adhesion has led to widespread applications in both the food and medical sectors. Notably, recent research highlights the probiotic efficacy of L. reuteri sourced from breast milk, particularly in influencing social behavior and mitigating atopic dermatitis. In this review, our emphasis is on surveying recent literature regarding the promotion of host's health by L. reuteri. We aim to provide a concise summary of the latest regulatory effects and potential mechanisms attributed to L. reuteri in the realms of metabolism, brain- and immune-related functions. The mechanism through which L. reuteri promotes host health by modulating the intestinal microenvironment primarily involves promoting intestinal epithelial renewal, bolstering intestinal barrier function, regulating gut microbiota and its metabolites, and suppressing inflammation and immune responses. Additionally, this review delves into new technologies, identifies shortcomings, and addresses challenges in current L. reuteri research. Finally, the application prospects of L. reuteri are provided. Therefore, a better understanding of the role and mechanisms of L. reuteri will contribute significantly to the development of new probiotic functional foods and enable precise, targeted interventions for various diseases.

Lactobacillus reuteri JCM 1112 ameliorates chronic acrylamide-induced glucose metabolism disorder via the bile acid-TGR5-GLP-1 axis and modulates intestinal oxidative stress in mice

Acrylamide (AA) is a toxic food contaminant that has been reported to cause glucose metabolism disorders (GMD) at high doses. However, it is unclear whether chronic low-dose AA can induce GMD and whether probiotics can alleviate AA-induced GMD. Here, C57BL/6N mice were orally administered with 5 mg per kg bw AA for 10 weeks, followed by another 3 weeks of glucagon-like peptide-1 (GLP-1) analogue (dulaglutide) treatment. Chronic low-dose AA exposure increased the blood glucose level and decreased serum insulin and GLP-1 levels, whereas dulaglutide treatment decreased the blood glucose level and increased the serum insulin level in AA-exposed mice. Then, mice were administered with AA or AA + INT-777 (Takeda G-protein-coupled receptor 5 (TGR5) agonist) for 10 weeks. INT-777 treatment reversed AA-induced downregulation of ileal TGR5 and proglucagon (PG) gene expression and decreased the serum GLP-1 level. These findings indicated that chronic low-dose AA induced GMD via inhibiting the TGR5-GLP-1 axis. Finally, mice were administered with AA for 10 weeks, followed by another 3 weeks of Lactobacillus reuteri JCM 1112 supplementation. L. reuteri supplementation significantly increased serum glucose, insulin and GLP-1 levels, upregulated ileal TGR5 and PG gene expression, and effectively restored the imbalance of bile acid (BA) metabolism in AA-exposed mice, demonstrating that L. reuteri ameliorates chronic AA-induced GMD via the BA-TGR5-GLP-1 axis. In addition, L. reuteri significantly enhanced ileal superoxide dismutase and catalase activities and total antioxidant capacity, thereby preventing chronic AA-induced oxidative stress. Our research provides new insights into the GMD toxicity of chronic low-dose AA and confirms the role of probiotics in alleviating AA-induced GMD.

Tomato Pectin Ameliorated Hepatic Steatosis in High-Fat-Diet Mice by Modulating Gut Microbiota and Bile Acid Metabolism

Nonalcoholic fatty liver disease (NAFLD) is a worldwide public health issue. Changes in the gut microbiota structure and composition are closely related to host pathophysiology processes. Pectin is associated with several beneficial health effects. In the present study, we aimed at investigating the effect of tomato pectin (TP) on hepatic steatosis and exploring the underlying mechanisms by focusing on the regulation of the gut microbiota-bile acid axis. Our results showed that TP attenuated high-fat diet (HFD)-induced liver steatosis and inflammation. TP administration increased the diversity of gut microbiota, enhancing the abundance of beneficial bacteria and suppressing the abundance of harmful or conditional pathogenic bacteria. Further antibiotic-caused microbiome depletion confirmed that the anti-NAFLD activities of TP were dependent on the regulation of gut microbiota. Besides, TP intervention affected feces bile acid metabolism and caused significant changes in functional conjugated bile acids, which in turn inhibited the ileum FXR/FGF15 signaling, leading to stimulation of the hepatic bile acid (BA) production. Furthermore, TP treatment accelerated BA excretion, promoted BA transportation, inhibited BA reabsorption, and facilitated cholesterol efflux to relieve HFD-induced hyperlipidemia. These findings provide a potential dietary intervention strategy for TP against NAFLD via modulation of cross-talk between BAs and gut bacteria.

Fucoxanthin extract ameliorates obesity associated with modulation of bile acid metabolism and gut microbiota in high-fat-diet fed mice

PURPOSE

Fucoxanthin extract (FX) is a type of carotenoid with a beneficial effect against obesity. The purpose of this study was to explore its precise action mechanism of losing weight.

METHODS

A high-fat diet induced obesity mouse model was established to study the effects of different doses of FX on C57BL/6J male mice for 12 weeks. Following intervention, serum indices, tissue sections, liver gene expression, and intestinal microorganisms were analyzed.

RESULTS

FX at low, medium, and high dosages (80, 160, and 320 mg/kg/day, respectively) for 12 weeks was associated with the lower body weight of mice when compared to that of high-fat-diet fed mice. It also improved glucose tolerance as well as serum lipid levels, and reduced fat accumulation. Significant regulation of bile acid metabolism and intestinal microbiota may contribute to the above effects. The bile acids in the FXH group were significantly increased. A low-dose and a medium-dose FX increased the level of transmembrane G protein-coupled receptor 5 (TGR5); a low-dose and high-dose FX increased the farnesoid X receptor (FXR) expression, and a medium-dose had no effect. 16S rRNA sequencing indicated that the Lachnospiraceae and Oscillospiraceae contributed to the beneficial effects of FX.

CONCLUSION

Our study sheds light on mechanisms behind the weight-lowering of FX, and manifested that bile acid metabolism and gut microbiota may be potential therapies. These results support that FX is a valuable candidate for promoting health and alleviating obesity.

Gut microbiota-mediated ursodeoxycholic acids regulate the inflammation of microglia through TGR5 signaling after MCAO

Ischemic stroke has been demonstrated to cause an imbalance of gut microbiota. However, the change in gut microbiota-mediated bile acids (BAs) metabolites remains unclear. Here, we observed a decrease in gut microbiota-mediated BAs, especially ursodeoxycholic acid (UDCA), in the serum of stroke patients as well as in the intestine, serum and brain of stroke mice. Restoration of UDCA could decrease the area of infarction and improve the neurological function and cognitive function in mice in association with inhibition of NLRP3-related pro-inflammatory cytokines through TGR5/PKA pathway. Furthermore, knocking out TGR5 and inhibiting PKA activity reduce the protective effect of UDCA. Taken together, our results suggest that microbiota-mediated UDCA plays an important role in alleviating inflammatory responses and might be a promising therapeutic target in ischemic stroke.

Inhibition of intestinal FXR activity as a possible mechanism for the beneficial effects of a probiotic mix supplementation on lipid metabolism alterations and weight gain in mice fed a high fat diet

Supplementation with probiotics has emerged as a promising therapeutic tool to manage metabolic diseases. We investigated the effects of a mix of Bifidobacterium animalis subsp. lactis LA804 and Lactobacillus gasseri LA806 on high-fat (HF) diet -induced metabolic disease in mice. Supplementation with the probiotic mix in HF diet-fed mice (HF-Pr2) reduced weight and fat mass gains, decreased hepatic lipid accumulation, and lowered plasma triglyceride peak during an oral lipid tolerance test. At the molecular level, the probiotic mix protected against HF-induced rise in mRNA levels of genes related to lipid uptake, metabolism, and storage in the liver and white adipose tissues, and strongly decreased mRNA levels of genes related to inflammation in the white adipose tissue and to oxidative stress in the liver. Regarding intestinal homeostasis, the probiotic mix did not prevent HF-induced gut permeability but slightly modified microbiota composition without correcting the dysbiosis induced by the HF diet. Probiotic supplementation also modified the cecal bile acid (BA) profile, leading to an increase in the Farnesoid-X-Receptor (FXR) antagonist/agonist ratio between BA species. In agreement, HF-Pr2 mice exhibited a strong inhibition of FXR signaling pathway in the ileum, which was associated with lipid metabolism protection. This is consistent with recent reports proposing that inhibition of intestinal FXR activity could be a potent mechanism to overcome metabolic disorders. Altogether, our results demonstrate that the probiotic mix evaluated, when administered preventively to HF diet-fed mice could limit obesity and associated lipid metabolism disorders, likely through the inhibition of FXR signaling in the intestinal tract.

Dual roles of nanocrystalline cellulose extracted from jute (Corchorus olitorius L.) leaves in resisting antibiotics and protecting probiotics

Antibiotics can cure diseases caused by bacterial infections, but their widespread use can have some side effects, such as probiotic reduction. There is an urgent need for such agents that can not only alleviate the damage caused by antibiotics, but also maintain the balance of the gut microbiota. In this study, we first characterized the nanocrystalline cellulose (NCC) extracted from plant jute (Corchorus olitorius L.) leaves. Next, we evaluated the protective effect of jute NCC and cellulose on human model gut bacteria (Lacticaseibacillus rhamnosus and Escherichia coli) under antibiotic stress by measuring bacterial growth and colony forming units. We found that NCC is more effective than cellulose in adsorbing antibiotics and defending the gut bacteria E. coli. Interestingly, the low-dose jute NCC clearly maintained the balance of key gut bacteria like Snodgrassella alvi and Lactobacillus Firm-4 in bees treated with tetracycline and reduced the toxicity caused by antibiotics. It also showed a more significant protective effect on human gut bacteria, especially L. rhamnosus, than cellulose. This study first demonstrated that low-dose NCC performed satisfactorily as a specific probiotic to mitigate the adverse effects of antibiotics on gut bacteria.

High-fructose corn syrup aggravates colitis via microbiota dysbiosis-mediated Th17/Treg imbalance

Dietary fructose is widely used in beverages, processed foods, and Western diets as food additives, and is closely related to the increased prevalence of multiple diseases, including inflammatory bowel disease (IBD). However, the detailed mechanism by which high fructose disrupts intestinal homeostasis remains elusive. The present study showed that high-fructose corn syrup (HFCS) administration exacerbated intestinal inflammation and deteriorated barrier integrity. Several in vivo experimental models were utilized to verify the importance of gut microbiota and immune cells in HFCS-mediated dextran sulfate sodium (DSS)-induced colitis. In addition, untargeted metabolomics analysis revealed the imbalance between primary bile acids (PBAs) and secondary bile acids (SBAs) in feces. Hence, high fructose was speculated to modulate gut microbiota community and reduced the relative abundance of Clostridium and Clostridium scindens at genus and species level respectively, followed by a decrease in SBAs, especially isoalloLCA, thereby affecting Th17/Treg cells equilibrium and promoting intestinal inflammation. These findings provide novel insights into the crosstalk between gut flora, bile acids, and mucosal immunity, and highlight potential strategies for precise treatment of IBD.

Lactobacillus reuteri Ameliorates Lipopolysaccharide-Induced Acute Lung Injury by Modulating the Gut Microbiota in Mice

Acute lung injury (ALI) causes lung inflammation and edema as well as resulting in gut microbiota disorder. Probiotics, however, can improve the gut microbiota composition and modulate its immune response, playing an important role in ALI pathogenesis. Therefore, our study aims to investigate the effect of Lactobacillus reuteri on Lipopolysaccharide (LPS)-induced ALI in mice and to probe the mechanism of its synergistic modulatory effect on the lungs and intestines. We assessed the therapeutic effects of L. reuteri in the ALI mouse model by histopathology, alveolar lavage fluid and serum inflammatory factor analysis and explored microbiome and transcriptome alterations. L. reuteri intervention effectively attenuated lung tissue injury and significantly reduced the LPS-induced inflammatory response and macrophage and neutrophil infiltration. Additionally, L. reuteri improved the intestinal barrier function and remodeled the disordered microbiota. In conclusion, our study showed that L. reuteri attenuated the inflammatory response, ameliorated the pulmonary edema, repaired the intestinal barrier, and remodeled the gut microbiota in ALI mice. This study provides new perspectives on the clinical treatment of ALI.

Obese Ningxiang pig-derived microbiota rewires carnitine metabolism to promote muscle fatty acid deposition in lean DLY pigs

The gut microbiota consistently shows strong correlations with lipid metabolism in humans and animals, and whether the gut microbiota contributes to muscle fatty acid (FA) deposition and meat traits in farm animals has not been fully resolved. In this study, we aimed to unveil the microbial mechanisms underlying muscle FA deposition in pigs. First, we systematically revealed the correlation between the gut microbiome and muscle FA levels in 43 obese Ningxiang pigs and 50 lean Duroc Landrace Yorkshire (DLY) pigs. Mutual fecal microbial transplantation showed that the obese Ningxiang pig-derived microbiota increased the muscle FA content and improved meat quality by reshaping the gut microbial composition in lean DLY pigs. Lactobacillus reuteri has been identified as a potential microbial biomarker in obese Ningxiang pig-derived microbiota-challenged DLY pigs. A gavage experiment using lean DLY pigs confirmed that L. reuteri XL0930 isolated from obese Ningxiang pigs was the causal species that increased the muscle FA content. Mechanistically, SLC22A5, a carnitine transporter, was downregulated in L. reuteri XL0930-fed DLY pigs, resulting in reduced muscle carnitine levels. Muscle and intestinal L-carnitine levels, which correlated with the muscle FA content, impeded fat synthesis and FA accumulation in in vitro and in vivo models. In conclusion, we uncovered an unexpected and important role of the obese Ningxiang pig-derived microbiota in regulating muscle FA metabolism via the SLC22A5-mediated carnitine system.

Gut microbiota bridges the iron homeostasis and host health

The gut microbiota acts as a symbiotic microecosystem that plays an indispensable role in the regulation of a number of metabolic processes in the host by secreting secondary metabolites and impacting the physiology and pathophysiology of numerous organs and tissues through the circulatory system. This relationship, referred to as the "gut-X axis", is associated with the development and progression of disorders, including obesity, fatty liver and Parkinson's disease. Given its importance, the gut flora is a vital research area for the understanding and development of the novel therapeutic approaches for multiple disorders. Iron is a common but necessary element required by both mammals and bacteria. As a result, iron metabolism is closely intertwined with the gut microbiota. The host's iron homeostasis affects the composition of the gut microbiota and the interaction between host and gut microbiota through various mechanisms such as nutrient homeostasis, intestinal peaceability, gut immunity, and oxidative stress. Therefore, understanding the relationship between gut microbes and host iron metabolism is not only of enormous significance to host health but also may offer preventative and therapeutic approaches for a number of disorders that impact both parties. In this review, we delve into the connection between the dysregulation of iron metabolism and dysbiosis of gut microbiota, and how it contributes to the onset and progression of metabolic and chronic diseases.

White adipose tissue undergoes browning during preweaning period in association with microbiota formation in mice

Beige adipocytes are transiently induced during early postnatal period in mice. Previous studies have suggested that, unlike in adults, the induction is independent of the sympathetic nerve activity; however, the mechanism is yet unknown. Here, we showed that beige adipocytes are induced during the preweaning period in association with the formation of microbiota in mice. Alteration of gut microbiota composition in preweaning mice by maternal treatment with antibiotics or high-fat diet feeding substantially suppressed WAT browning. The suppression was also found in pups transplanted cecal microbiota from pups of high-fat diet-fed dams. These treatments reduced the hepatic expression of genes involved in bile acid synthesis and the serum bile acids level. The abundance of Porphyromonadaceae and Ruminococcaceae in microbiota showed a positive and negative correlation with the induction of beige adipocytes, respectively. This finding may provide comprehensive understanding of the association between gut microbiota and adipose tissue development in the neonatal period.

Lactobacillus plantarum HF02 alleviates lipid accumulation and intestinal microbiota dysbiosis in high-fat diet-induced obese mice

BACKGROUND

Obesity is closely associated with lipid accumulation and intestinal microbiota dysbiosis. It has been proved that probiotics supplement contributes to alleviate obesity. The objective of this study was to investigate the mechanism by which Lactobacillus plantarum HF02 (LP-HF02) alleviated lipid accumulation and intestinal microbiota dysbiosis in high-fat diet-induced obese mice.

RESULTS

Our results showed that LP-HF02 ameliorated body weight, dyslipidemia, liver lipid accumulation, and liver injury in obese mice. As expected, LP-HF02 inhibited pancreatic lipase activity in small intestinal contents and increased fecal triglyceride levels, thereby reducing dietary fat hydrolysis and absorption. Moreover, LP-HF02 ameliorated the intestinal microbiota composition, as evidenced by the enhanced ratio of Bacteroides to Firmicutes, the decreased abundance of pathogenic bacteria (including Bacteroides, Alistipes, Blautia, and Colidextribacter) and the increased abundance of beneficial bacteria (including Muribaculaceae, Akkermansia, Faecalibaculum, and Rikenellaceae_RC9_gut_group). LP-HF02 also increased fecal short-chain fatty acids (SCFAs) levels and colonic mucosal thickness, and subsequently decreased serum lipopolysaccharide (LPS), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) levels in obese mice. Additionally, reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot results demonstrated that LP-HF02 ameliorated hepatic lipid accumulation via activating the adenosine monophosphate (AMP)-activated protein kinase (AMPK) pathway.

CONCLUSION

Therefore, our results indicated that LP-HF02 could be considered as a probiotic preparation for preventing obesity. © 2023 Society of Chemical Industry.

Modulation of the Microbiome-Fat-Liver Axis by Lactic Acid Bacteria: A Potential Alleviated Role in High-Fat-Diet-Induced Obese Mice

The major characteristics of obesity are abnormal lipid metabolism, chronic inflammation, and imbalanced gut microbiota. It has been reported that lactic acid bacteria (LAB) possess potential for alleviating obesity, considering which the strain-specific functions and diverse mechanisms and the roles and mechanisms of various LAB are worthy of investigation. This study aimed to validate and investigate the alleviating effects and underlying mechanisms of three LAB strains, Lactiplantibacillus plantarum NCUH001046 (LP), Limosilactobacillus reuteri NCUH064003, and Limosilactobacillus fermentum NCUH003068 (LF), in high-fat-diet-induced obese mice. The findings demonstrated that the three strains, particularly LP, suppressed body weight gain and fat deposition; ameliorated lipid disorders, liver and adipocyte morphology, and chronic low-grade inflammation; and reduced lipid synthesis via activating the adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling pathway. In addition, LP and LF decreased the enrichment of bacteria positively correlated with obesity, like Mucispirillum, Olsenella, and Streptococcus, but facilitated the growth of beneficial bacteria negatively correlated with obesity, like Roseburia, Coprococcus, and Bacteroides, along with increasing the short-chain fatty acid levels. It is deduced that the underlying alleviating mechanism of LP was to modulate the hepatic AMPK signaling pathway and gut microbiota by the microbiome-fat-liver axis to alleviate obesity development. In conclusion, as a diet supplement, LP has promising potential in obesity prevention and treatment.

Prevention of High-Fat-Diet-Induced Dyslipidemia by Lactobacillus plantarum LP104 through Mediating Bile Acid Enterohepatic Axis Circulation and Intestinal Flora

This work aimed to investigate the alleviative mechanism of Lactobacillus plantarum LP104 (LP104) isolated from kimchi on high-fat-diet-induced dyslipidemia by targeting the intestinal flora and bile acid (BA) metabolism. Oral administration of LP104 over 8 weeks reduced body weight gain and body fat, as well as ameliorating serum and hepatic dyslipidemia in HFD-fed C57BL/6N mice significantly. LP104 intervention also increased the ileal tauro-α/β-muricholic acid sodium salt (T-α-MCA or T-β-MCA) and tauroursodeoxycholic acid (TUDCA) concentrations to suppress the enterohepatic farnesoid X receptor/fibroblast growth factor 15-fibroblast growth factor receptor 4 (FXR/FGF15-FGFR4) signaling pathway, which stimulated the hepatic cholic acid (CA) and chenodeoxycholic acid (CDCA) de novo synthesis through using cholesterol. Then, LP104 treatment accelerated BA excretion with the feces and cholesterol efflux to improve HFD-caused hyperlipidemia effectively. The 16S rRNA gene high-throughput sequencing revealed that LP104 promoted intestinal flora rebalance by increasing the abundances of Bacteroides, Akkermansia, Lactobacillus, and Clostridium and decreasing the abundance of Oscillospira and Coprococcus. Meanwhile, Spearman correlation analysis demonstrated that the differential flora were closely related to BA signaling molecules including CA, CDCA, T-α-MCA, T-β-MCA, and TUDCA after LP104 intervention. These findings provided new evidence that LP104 had the potential to be used as a naturally functional food for the prevention of dyslipidemia.

Potential use of seaweed polysaccharides as prebiotics for management of metabolic syndrome: a review

Seaweed polysaccharides (SPs) obtained from seaweeds are a class of functional prebiotics. SPs can regulate glucose and lipid anomalies, affect appetite, reduce inflammation and oxidative stress, and therefore have great potential for managing metabolic syndrome (MetS). SPs are poorly digested by the human gastrointestinal tract but are available to the gut microbiota to produce metabolites and exert a series of positive effects, which may be the mechanism by which SPs render their anti-MetS effects. This article reviews the potential of SPs as prebiotics in the management of MetS-related metabolic disturbances. The structure of SPs and studies related to the process of their degradation by gut bacteria and their therapeutic effects on MetS are highlighted. In summary, this review provides new perspectives on SPs as prebiotics to prevent and treat MetS.

Probiotic Limosilactobacillus Reuteri (Lactobacillus Reuteri) Extends the Lifespan of Drosophila Melanogaster through Insulin/IGF-1 Signaling

The term probiotic refers to bacteria that provide a beneficial effect to the host. Limosilactobacillus reuteri (Lactobacillus reuteri) is a probiotic isolated from human breast milk. Although L. reuteri has antimicrobial and anti-inflammatory activities occasionally linked to anti-aging effects, there are no reports of the effects of L. reuteri on longevity. This study evaluated the anti-aging effects of L. reuteri on the lifespan and physiology of Drosophila melanogaster. L. reuteri increased the mean lifespan of fruit flies significantly without reducing the reproductive output, food intake, or locomotor activity. Furthermore, the data suggested that the longevity effect of L. reuteri is mediated by the reduction of the insulin/IGF-1 signaling pathway and the action of reuterin, an antimicrobial compound produced by L. reuteri. These results show that L. reuteri can be used as a probiotic that acts as a dietary restriction mimetic with anti-aging effects.

Experimental diets dictate the metabolic benefits of probiotics in obesity

Growing evidence supports the use of probiotics to prevent or mitigate obesity-related dysmetabolism and non-alcoholic fatty liver disease (NAFLD). However, frequent reports of responders versus non-responders to probiotic treatment warrant a better understanding of key modifiers of host-microbe interactions. The influence of host diet on probiotic efficacy, in particular against metabolic diseases, remains elusive. We fed C57BL6/J mice a low fat reference diet or one of two energy-matched high fat and high sucrose diets for 12 weeks; a classical high fat diet (HFD) and a customized fast food-mimicking diet (FFMD). During the studies, mice fed either obesogenic diet were gavaged daily with one of two probiotic lactic acid bacteria (LAB) strains previously classified as Lactobaccillus, namely Limosilactobacillus reuteri (L. reuteri)or Lacticaseibacillus paracaseisubsp. paracasei (L. paracasei), or vehicle. The tested probiotics exhibited a reproducible efficacy but dichotomous response according to the obesogenic diets used. Indeed, L. paracaseiprevented weight gain, improved insulin sensitivity, and protected against NAFLD development in mice fed HFD, but not FFMD. Conversely, L. reuteri improved glucoregulatory capacity, reduced NAFLD development, and increased distal gut bile acid levels associated with changes in predicted functions of the gut microbiota exclusively in the context of FFMD-feeding. We found that the probiotic efficacy of two LAB strains is highly dependent on experimental obesogenic diets. These findings highlight the need to carefully consider the confounding impact of diet in order to improve both the reproducibility of preclinical probiotic studies and their clinical research translatability.

Nanocrystalline Cellulose Cures Constipation via Gut Microbiota Metabolism

Constipation can seriously affect the quality of life and increase the risk of colorectal cancer. The present strategies for constipation therapy have adverse effects, such as causing irreversible intestinal damage and affecting the absorption of nutrients. Nanocrystalline cellulose (NCC), which is from natural plants, has good biocompatibility and high safety. Herein, we used NCC to treat constipation assessed by the black stool, intestinal tissue sections, and serum biomarkers. We studied the effect of NCC on gut microbiota and discussed the correlation of gut microbiota and metabolites. We evaluated the long-term biosafety of NCC. NCC could effectively treat constipation through gut microbiota metabolism, which required a small dosage and did not affect the organs and intestines. NCC could be used as an alternative to medications and dietary fiber for constipation therapy.

Exploring a Possible Link between the Fecal Microbiota and the Production Performance of Pigs

The backfat thickness of pigs not only affects the physical properties and taste of meat, but it also closely relates to the reproduction performance of sows. Accumulating evidence indicates that, apart from genetic factors, gut microbiota can also modulate the fat deposition and muscle growth. However, the differential microbiota in pigs with different backfat thickness, and whether microbiota affects backfat thickness, remains elusive. Firstly, 16S ribosomal RNA (16S rRNA) gene sequencing was performed on 62 fecal samples from pigs with different backfat thicknesses, and the compositions of microbiota among different groups with different backfat thicknesses were different. The abundance of Lactobacillus. reuteri (L. reuteri) and Prevotella sp RS2 was significantly higher in pigs with low-backfat thickness than that in pigs with middle and high-backfat thickness; meanwhile, the abundance of Desulfovibrio piger was significantly lower (p < 0.05) in pigs with low-backfat thickness. Furthermore, the functional profiling of microbial communities suggested that the abundance of isoquinoline alkaloid biosynthesis and styrene degradation were significantly lower (p < 0.05) in the low-backfat thickness group than that in middle and high-backfat thickness groups. Finally, L. reuteri fed to Meishan piglets was capable of improving the production performance and had the potential to reduce backfat thickness. This study provides new evidence that microbiota can regulate the phenotype of the host, and dietary supplementation with L. reuteri can improve the production performance of piglets.

Soybean isoflavones modulate gut microbiota to benefit the health weight and metabolism

Soybean isoflavones (SIs) are widely found in food and herbal medicines. Although the pharmacological activities of SIs have been widely reported, their effects on the intestinal microecology of normal hosts have received little attention. Five-week-old Kunming (KM) mice were administered SIs (10 mg/kg/day) for 15 days. Food intake, body weight, and digestive enzyme activity were measured. Small intestine microbiota, including lumen-associated bacteria (LAB) and mucosa-associated bacteria (MAB), were analyzed using 16S ribosomal ribonucleic acid (16S rRNA) gene sequencing. Short-chain fatty acids (SCFAs) were analyzed using gas chromatography-mass spectrometry (GC-MS). The results showed that the mice that consuming SIs showed a higher food intake but a lower body weight gain rate than that of normal mice. Sucrase, cellulase, and amylase activities reduced, while protease activity increased after SIs intervention. Moreover, SIs increased the intestinal bacterial diversity in both LAB and MAB of normal mice. The composition of LAB was more sensitive to SIs than those of MAB. Lactobacillus, Adlercreutzia, Coprococcus, Ruminococcus, Butyricicoccus, and Desulfovibrio were the differential bacteria among the LAB of mice treated with SIs. In addition, acetic acid, valeric acid, isobutyric acid, isovaleric acid, and caproic acid decreased, while butyric acid and propionic acid increased in the mice treated with SIs. Taken together, SIs are beneficial for weight control, even in short-term interventions. The specific mechanism is related to regulating the gut microbiota, changing digestive enzyme activities, and further affecting carbohydrate absorption and metabolism.

Present and Future: Crosstalks Between Polycystic Ovary Syndrome and Gut Metabolites Relating to Gut Microbiota

Polycystic ovary syndrome (PCOS) is a common disease, affecting 8%-13% of the females of reproductive age, thereby compromising their fertility and long-term health. However, the pathogenesis of PCOS is still unclear. It is not only a reproductive endocrine disease, dominated by hyperandrogenemia, but also is accompanied by different degrees of metabolic abnormalities and insulin resistance. With a deeper understanding of its pathogenesis, more small metabolic molecules, such as bile acids, amino acids, and short-chain fatty acids, have been reported to be involved in the pathological process of PCOS. Recently, the critical role of gut microbiota in metabolism has been focused on. The gut microbiota-related metabolic pathways can significantly affect inflammation levels, insulin signaling, glucose metabolism, lipid metabolism, and hormonal secretions. Although the abnormalities in gut microbiota and metabolites might not be the initial factors of PCOS, they may have a significant role in the pathological process of PCOS. The dysbiosis of gut microbiota and disturbance of gut metabolites can affect the progression of PCOS. Meanwhile, PCOS itself can adversely affect the function of gut, thereby contributing to the aggravation of the disease. Inhibiting this vicious cycle might alleviate the symptoms of PCOS. However, the role of gut microbiota in PCOS has not been fully explored yet. This review aims to summarize the potential effects and modulative mechanisms of the gut metabolites on PCOS and suggests its potential intervention targets, thus providing more possible treatment options for PCOS in the future.