Threonine supplementation prevents the development of fat deposition in mice fed a high-fat diet

Soybean hull polysaccharides ameliorate lipid metabolic disorders and gut microbiota dysbiosis in high-fat diet-fed zebrafish

Soybean hull polysaccharide (ASP), a pectic polysaccharide with potential effects on regulating lipid metabolism through gut microbiota and their metabolites, was studied to explore its regulatory mechanisms. The study examined the alleviating effect of ASP on high-fat diet (HFD) zebrafish through histopathological examination and biochemical analysis. Additionally, the lipid-lowering mechanism was analyzed combined with metabolomics and the proliferation of gut microbiota. Results showed that ASP significantly ameliorated body weight and blood lipids and also reduced hepatic lipid accumulation and hepatic lipid peroxidation damage. Bioinformatics analyses showed that ASP administration (240 μg/day) generated significant gut microbiota structural changes in high-fat diet-fed zebrafish, in particular, reducing Proteobacteria and increasing Cetobacterium relative abundance levels. ASP upregulates propionic acid, linoleic acid, 6-hydroxyhexanoic acid, and l-threonine biosynthesis by mediating gut microbiota regulation of amino acid and lipid metabolic pathways. Utilizing a correlation network derived from Spearman's correlation coefficients, significant microbial phylotypes that react to ASP demonstrated a strong association with parameters linked to lipid metabolic disorders. Fecal metabolites (e.g. propionic acid) were positively correlated with gut microbiota (e.g. Cetobacterium) in the high-dose ASP group. Our results provide a theoretical basis for new ASP prebiotic formulations to target the gut microbiota and prevent lipid metabolic disorders.

Threonine modulates the STAT3-SCD1 pathway to reduce fatty acid metabolism in duck hepatocytes

Dietary threonine (Thr) is known to influence fat deposition in poultry, but the precise mechanisms behind its regulatory effects on hepatic lipid metabolism remain elusive. Prior research indicated that including supplemental Thr in the feed may influence STAT3 (Signal Transducer and Activator of Transcription 3) levels in the liver of meat ducks. Numerous studies have recorded the function of STAT3 in regulating fatty acid (FA) metabolism in mammals. The primary objective of this study was to investigate whether Thr influences FA metabolism and triglycerides (TG) deposition in duck liver by regulating STAT3 expression. Primary hepatocytes were isolated from duck embryos and treated for 36 h with different doses of Thr (0, 10, 25, 50, 200 μM) in vitro or with a constructed STAT3 overexpression plasmid to examine the content of FAs and TG. RNA-seq was used to detect changes in gene expression in hepatocytes following STAT3 overexpression. The results demonstrated that both the exogenous addition of Thr and the overexpression of STAT3 significantly suppressed the capacity of hepatocytes for FAs deposition (P < 0.05). The overexpression of STAT3 also inhibited TG accumulation under conditions in response to Thr deficiency (P < 0.01). Transcriptomic analyses indicated that the overexpression of STAT3 inhibits the activity of triglyceride metabolism and unsaturated fatty acid biosynthesis (P < 0.01). Finally, a dual-luciferase reporter test demonstrated that STAT3 may systematically target and inhibit SCD1 transcription (P < 0.01). The present study indicates that supplemental Thr (50 μM) inhibits hepatic FA deposition via the STAT3-SCD1 pathway. This work enhances our comprehension of the functional roles of Thr and STAT3 in modulating lipid metabolism within duck livers. Moreover, it provides a partial theoretical foundation for the nutritional prevention and pharmacological intervention of lipid metabolism disorders in poultry.

Systems biology approaches identify metabolic signatures of dietary lifespan and healthspan across species

Dietary restriction (DR) is a potent method to enhance lifespan and healthspan, but individual responses are influenced by genetic variations. Understanding how metabolism-related genetic differences impact longevity and healthspan are unclear. To investigate this, we used metabolites as markers to reveal how different genotypes respond to diet to influence longevity and healthspan traits. We analyzed data from Drosophila Genetic Reference Panel (DGRP) strains raised under AL and DR conditions, combining metabolomic, phenotypic, and genome-wide information. We employed two computational and complementary methods across species-random forest modeling within the DGRP as our primary analysis and Mendelian randomization in human cohorts as a secondary analysis. We pinpointed key traits with cross-species relevance as well as underlying heterogeneity and pleiotropy that influence lifespan and healthspan. Notably, orotate was linked to parental age at death in humans and blocked the DR lifespan extension in flies, while threonine supplementation extended lifespan, in a strain- and sex-specific manner. Thus, utilizing natural genetic variation data from flies and humans, we employed a systems biology approach to elucidate potential therapeutic pathways and metabolomic targets for diet-dependent changes in lifespan and healthspan.

Threonine Deficiency Increases Triglyceride Deposition in Primary Duck Hepatocytes by Reducing STAT3 Phosphorylation

Liver lipid metabolism disruption significantly contributes to excessive fat buildup in waterfowl. Research suggests that the supplementation of Threonine (Thr) in the diet can improve liver lipid metabolism disorder, while Thr deficiency can lead to such metabolic disorders in the liver. The mechanisms through which Thr regulates lipid metabolism remain unclear. STAT3 (signal transducer and activator of transcription 3), a crucial transcription factor in the JAK-STAT (Janus kinase-signal transducer and activator of transcription) pathway, participates in various biological processes, including lipid and energy metabolism. This research investigates the potential involvement of STAT3 in the increased lipid storage seen in primary duck hepatocytes as a result of a lack of Thr. Using small interfering RNA and Stattic, a specific STAT3 phosphorylation inhibitor, we explored the impact of STAT3 expression patterns on Thr-regulated lipid synthesis metabolism in hepatocytes. Through transcriptome sequencing, we uncovered pathways related to lipid synthesis and metabolism jointly regulated by Thr and STAT3. The results showed that Thr deficiency increases lipid deposition in primary duck hepatocytes (p < 0.01). The decrease in protein and phosphorylation levels of STAT3 directly caused this deposition (p < 0.01). Transcriptomic analysis revealed that Thr deficiency and STAT3 knockdown jointly altered the mRNA expression levels of pathways related to long-chain fatty acid synthesis and energy metabolism (p < 0.05). Thr deficiency, through mediating STAT3 inactivation, upregulated ELOVL7, PPARG, MMP1, MMP13, and TIMP4 mRNA levels, and downregulated PTGS2 mRNA levels (p < 0.01). In summary, these results suggest that Thr deficiency promotes lipid synthesis, reduces lipid breakdown, and leads to lipid metabolism disorders and triglyceride deposition by downregulating STAT3 activity in primary duck hepatocytes.

Aqueous extract of fermented Eucommia ulmoides leaves alleviates hyperlipidemia by maintaining gut homeostasis and modulating metabolism in high-fat diet fed rats

BACKGROUND

As a traditional Chinese medicinal herb, the lipid-lowing biological potential of Eucommia ulmoides leaves (EL) has been demonstrated. After fermentation, the EL have been made into various products with lipid-lowering effects and antioxidant activity. However, the anti-hyperlipidemic mechanism of fermented Eucommia ulmoides leaves (FEL) is unclear now.

PURPOSE

To evaluate the effects of FEL on hyperlipidemia and investigate the mechanism based on regulating gut homeostasis and host metabolism.

METHODS

Hyperlipidemia animal model in Wistar rats was established after 8 weeks high-fat diet (HFD) fed. The administered doses of aqueous extract of FEL (FELE) were 128, 256 and 512 mg/kg/d, respectively. Serum biochemical parameters detection, histopathological sections analysis, 16S rDNA sequencing of gut microbiota and untargeted fecal metabolomics analysis, were performed to determine the therapeutic effects and predict related pathways of FELE on hyperlipidemia. The changes of proteins and genes elated to lipid were detected by Immunofluorescence (IF) and quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

56 Components in FELE were identified by UPLC-MS, with organic acids, flavonoids and phenolic acids accounting for the majority. The intervention of FELE significantly reduced the body weight, lipid accumulation and the levels of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein-cholesterol (LDL-C) in hyperlipidemia rats, while increased the level of High-density lipoprotein-cholesterol (HDL-C). Meanwhile, FELE improved the inflammatory makers and oxidative stress factors, which is tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT). These results demonstrated that FETE can effectively reduce blood lipids and alleviate inflammation and oxidative damage caused by hyperlipidemia. Mechanistically, FELE restore the homeostasis of gut microbiota by reducing the Firmicutes/Bacteroidetes ratio and increasing the abundance of probiotics, especially Lactobacillus, Rombousia, Bacteroides, Roseburia, Clostridia_UCG-014_Unclassified, while modulated metabolism through amino acid, bile acid and lipid-related metabolism pathways. In addition, the Pearson correlation analysis found that the upregulated bilirubin, threonine, dopamine and downregulated lipocholic acid, d-sphingosine were key metabolites after FELE intervention. IF and qRT-PCR analysis showed that FELE upregulated the expression of fatty acid oxidation proteins and genes (PPARα, CPT1A), bile acid synthesis and excretion proteins and genes (LXRα, CYP7A1, FXR), and downregulated the expression of adipogenic gene (SREBP-1c) by regulating gut microbiota to improve metabolism and exert a lipid-lowering effect.

CONCLUSION

This work filled the lipid-lowering mechanism gap of FEL. FELE can improve HFD-induced hyperlipidemia by regulating the gut microbiota homeostasis and metabolism. Thus, FEL has the potential to develop into the novel raw material of lipid-lowering drugs.

Metabolic liability for weight gain in early adulthood

While weight gain is associated with a host of chronic illnesses, efforts in obesity have relied on single "snapshots" of body mass index (BMI) to guide genetic and molecular discovery. Here, we study >2,000 young adults with metabolomics and proteomics to identify a metabolic liability to weight gain in early adulthood. Using longitudinal regression and penalized regression, we identify a metabolic signature for weight liability, associated with a 2.6% (2.0%-3.2%, p = 7.5 × 10-19) gain in BMI over ≈20 years per SD higher score, after comprehensive adjustment. Identified molecules specified mechanisms of weight gain, including hunger and appetite regulation, energy expenditure, gut microbial metabolism, and host interaction with external exposure. Integration of longitudinal and concurrent measures in regression with Mendelian randomization highlights the complexity of metabolic regulation of weight gain, suggesting caution in interpretation of epidemiologic or genetic effect estimates traditionally used in metabolic research.

Molecular mechanism and therapeutic significance of essential amino acids in metabolically associated fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), also known as metabolically associated fatty liver disease (MAFLD), is a systemic metabolic disease characterized by lipid accumulation in the liver, lipid toxicity, insulin resistance, intestinal dysbiosis, and inflammation that can progress from simple steatosis to nonalcoholic steatohepatitis (NASH) and even cirrhosis or cancer. It is the most prevalent illness threatening world health. Currently, there are almost no approved drug interventions for MAFLD, mainly dietary changes and exercise to control weight and regulate metabolic disorders. Meanwhile, the metabolic pathway involved in amino acid metabolism also influences the onset and development of MAFLD in the body, and most amino acid metabolism takes place in the liver. Essential amino acids are those amino acids that must be supplemented from outside the diet and that cannot be synthesized in the body or cannot be synthesized at a rate sufficient to meet the body's needs, including leucine, isoleucine, valine (collectively known as branched-chain amino acids), tryptophan, phenylalanine (which are aromatic amino acids), histidine, methionine, threonine and lysine. The metabolic balance of the body is closely linked to these essential amino acids, and essential amino acids are closely linked to the pathophysiological process of MAFLD. In this paper, we will focus on the metabolism of essential amino acids in the body and further explore the therapeutic strategies for MAFLD based on the studies conducted in recent years.

The "crosstalk" between microbiota and metabolomic profile in high-fat-diet-induced obese mice supplemented with Bletilla striata polysaccharides and composite polysaccharides

The potential prebiotic feature of Bletilla striata polysaccharides (BSP) has been widely accepted, while the beneficial effect of BSP on high-fat-diet-induced obesity is unclear. Moreover, the "crosstalk" between microbiota and metabolomic profile in high-fat-diet-induced obese mice supplemented with BSP still need to be further explored. The present study attempted to illustrate the effect of BSP and/or composite polysaccharides on high-fat-diet-induced obese mice by combining multi-matrix (feces, urine, liver) metabolomics and gut microbiome. The results showed that BSP and/or composite polysaccharides were able to reduce the abnormal weight gain induced by high-fat diet. A total of 175 molecules were characterized by proton nuclear magnetic resonance (1H NMR) in feces, urine and liver, suggesting that multi-matrix metabolomics could provide a comprehensive view of metabolic regulatory mechanism of BSP in high-fat-diet-induced obese mice. Several pathways were altered in response to BSP supplementation, mainly pertaining to amino acid, purine, pyrimidine, ascorbate and aldarate metabolisms. In addition, BSP ameliorated high-fat-diet-induced imbalanced gut microbiome, by lowering the ratio of Firmicutes/Bacteroidetes. Significant correlations were illustrated between particular microbiota's features and specific metabolites. Overall, the anti-obesity effect of BSP could be attributed to the amelioration of the disorders of gut microbiota and to the regulation of the "gut-liver axis" metabolism.

Heat-moisture treatment enhances the ordered degree of starch structure in whole chestnut flour and alters its gut microbiota modulation in mice fed with high-fat diet

Currently, chestnuts attract more attention among consumers due to its rich nutritional functions, but systematic evaluation on the effect of thermal processing on its nutritional value is still limited. In this work, based on results of microstructural properties that heat-moisture treatment (HMT) could enhance the total ordered degree of starch structure in whole chestnut flour (CN) and promote the formation of anti-enzymatic component, in vitro experiment was then conducted and confirmed that HMT could significantly reduce the predicted glycemic index (pGI) of CN from 75.6 to 64.3 and improve its dietary fiber content from 7.06 to 13.42 g/100 g (p < 0.05). Further dietary intervention studies with CN and heat-moisture treated CN (HMT-CN) supplementation on the high-fat diet (HFD) consuming mice were discussed in terms of gut microbiota and its metabolites changes. The results showed that both CN and HMT-CN significantly resisted the weight gain induced by HFD, while HMT-CN had better serum lipid regulation effect. However, they had different effects on the gut metabolism pathways, among which CN inhibited the production of stearamine by promoting the proliferation of Dubosiella, while HMT-CN contributed to the growth of Lachnoclostridium, Desulfovibrio, and Faecalibaculum which stimulated the formation of associated metabolites including jwh-018-d11, valylproline, tetranor-12(S)-HETE, and PA (3:0/18:0). Overall, these discoveries could provide basic data for the effective utilization of CN in food industry processing.

Abrupt Photoperiod Changes Differentially Modulate Hepatic Antioxidant Response in Healthy and Obese Rats: Effects of Grape Seed Proanthocyanidin Extract (GSPE)

Disruptions of the light/dark cycle and unhealthy diets can promote misalignment of biological rhythms and metabolic alterations, ultimately leading to an oxidative stress condition. Grape seed proanthocyanidin extract (GSPE), which possesses antioxidant properties, has demonstrated its beneficial effects in metabolic-associated diseases and its potential role in modulating circadian disruptions. Therefore, this study aimed to assess the impact of GSPE administration on the liver oxidant system of healthy and diet-induced obese rats undergoing a sudden photoperiod shift. To this end, forty-eight photoperiod-sensitive Fischer 344/IcoCrl rats were fed either a standard (STD) or a cafeteria diet (CAF) for 6 weeks. A week before euthanizing, rats were abruptly transferred from a standard photoperiod of 12 h of light/day (L12) to either a short (6 h light/day, L6) or a long photoperiod (18 h light/day, L18) while receiving a daily oral dose of vehicle (VH) or GSPE (25 mg/kg). Alterations in body weight gain, serum and liver biochemical parameters, antioxidant gene and protein expression, and antioxidant metabolites were observed. Interestingly, GSPE partially ameliorated these effects by reducing the oxidative stress status in L6 through an increase in GPx1 expression and in hepatic antioxidant metabolites and in L18 by increasing the NRF2/KEAP1/ARE pathway, thereby showing potential in the treatment of circadian-related disorders by increasing the hepatic antioxidant response in a photoperiod-dependent manner.

Serum metabolomic profiling unveils distinct sex-related metabolic patterns in NAFLD

Objective

Obesity poses an increased risk for the onset of Nonalcoholic fatty liver disease (NAFLD). The influence of other factors, such as sex in the incidence and severity of this liver disease has not yet been fully elucidated. Thus, we aimed to identify the NAFLD serum metabolic signatures associated with sex in normal, overweight and obese patients and to associate the metabolite fluctuations across the increasing liver steatosis stages.

Methods and results

Using nuclear magnetic resonance (NMR) serum samples of 210 NAFLD cases and control individuals diagnosed with liver U/S, our untargeted metabolomics enquiry provided a sex distinct metabolic bouquet. Increased levels of alanine, histidine and tyrosine are associated with severity of NAFLD in both men and women. Moreover, higher serum concentrations of valine, aspartic acid and mannose were positively associated with the progression of NAFLD among the male subjects, while a negative association was observed with the levels of creatine, phosphorylcholine and acetic acid. On the other hand, glucose was positively associated with the progression of NAFLD among the female subjects, while levels of threonine were negatively related. Fluctuations in ketone bodies acetoacetate and acetone were also observed among the female subjects probing a significant reduction in the circulatory levels of the former in NAFLD cases. A complex glycine response to hepatic steatosis of the female subjects deserves further investigation.

Conclusion

Results of this study aspire to address the paucity of data on sex differences regarding NAFLD pathogenesis. Targeted circulatory metabolome measurements could be used as diagnostic markers for the distinct stages of NAFLD in each sex and eventually aid in the development of novel sex-related therapeutic options.

Multi-omics approach to socioeconomic disparity in metabolic syndrome reveals roles of diet and microbiome

The epidemy of metabolic syndrome (MetS) is typically preceded by adoption of a "risky" lifestyle (e.g., dietary habit) among populations. Evidence shows that those with low socioeconomic status (SES) are at an increased risk for MetS. To investigate this, we recruited 123 obese subjects (body mass index [BMI] ≥ 30) from Chicago. Multi-omic data were collected to interrogate fecal microbiota, systemic markers of inflammation and immune activation, plasma metabolites, and plasma glycans. Intestinal permeability was measured using the sugar permeability testing. Our results suggest a heterogenous metabolic dysregulation among obese populations who are at risk of MetS. Systemic inflammation, linked to poor diet, intestinal microbiome dysbiosis, and gut barrier dysfunction may explain the development of MetS in these individuals. Our analysis revealed 37 key features associated with increased numbers of MetS features. These features were used to construct a composite metabolic-inflammatory (MI) score that was able to predict progression of MetS among at-risk individuals. The MI score was correlated with several markers of poor diet quality as well as lower levels of gut microbial diversity and abnormalities in several species of bacteria. This study reveals novel targets to reduce the burden of MetS and suggests access to healthy food options as a practical intervention.

Longitudinal Gut Microbiota Dysbiosis Underlies Olanzapine-Induced Weight Gain

Olanzapine is one of the most effective medicines available for stabilizing schizophrenia spectrum disorders. However, it has been reported to show the greatest propensity for inducing body weight gain and producing metabolic side effects, which cause a great burden in patients with psychiatric disorders. Since the gut microbiota has a profound impact on the initiation and development of metabolic diseases, we conducted a longitudinal study to explore its role in olanzapine-induced obesity and metabolic abnormalities. Female Sprague-Dawley rats were treated with different doses of olanzapine, and metabolic and inflammatory markers were measured. Olanzapine significantly induced body weight gain (up to a 2.1-fold change), which was accompanied by hepatic inflammation and increased plasma triglyceride levels (up to a 2.9-fold change), as well as gut microbiota dysbiosis. Subsequently, fuzzy c-means clustering was used to characterize three clusters of longitudinal trajectories for microbial fluctuations: (i) genera continuing to increase, (ii) genera continuing to decrease, and (iii) genera temporarily changing. Among them, Enterorhabdus (r = 0.38), Parasutterella (r = 0.43), and Prevotellaceae UCG-001 (r = 0.52) positively correlated with body weight gain. In addition, two MetaCyc metabolic pathways were identified as associated with olanzapine-induced body weight gain, including the superpathway of glucose and xylose degradation and the superpathway of l-threonine biosynthesis. In conclusion, we demonstrate that olanzapine can directly alter the gut microbiota and rapidly induce dysbiosis, which is significantly associated with body weight gain. This may suggest gut microbiota targets in future studies on metabolic abnormalities caused by olanzapine. IMPORTANCE Olanzapine is one of the most effective second-generation antipsychotics for stabilizing schizophrenia spectrum disorders. However, olanzapine has multiple drug-induced metabolic side effects, including weight gain. This study provides insight to the gut microbiota target in olanzapine-induced obesity. Specifically, we explored the longitudinal gut microbiota trajectories of female Sprague-Dawley rats undergoing olanzapine treatment. We showed that olanzapine treatment causes a dynamic alteration of gut microbiota diversity. Additionally, we identified three genera, Parasutterella, Enterorhabdus, and Prevotellaceae UCG-001, that may play an important role in olanzapine-induced obesity. In this case, the supply or removal of specific elements of the gut microbiota may represent a promising avenue for treatment of olanzapine-related metabolic side effects.

Metabolomics analysis in rat hearts with ischemia/reperfusion injury after diazoxide postconditioning

Background: Diazoxide is a selective mitochondrial-sensitive potassium channel opening agent that has a definite effect on reducing myocardial ischemia/reperfusion injury (MIRI). However, the exact effects of diazoxide postconditioning on the myocardial metabolome remain unclear, which might contribute to the cardioprotective effects of diazoxide postconditioning. Methods: Rat hearts subjected to Langendorff perfusion were randomly assigned to the normal (Nor) group, ischemia/reperfusion (I/R) group, diazoxide (DZ) group and 5-hydroxydecanoic acid + diazoxide (5-HD + DZ) group. The heart rate (HR), left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), and maximum left ventricular pressure (+dp/dtmax) were recorded. The mitochondrial Flameng scores were analysed according to the ultrastructure of the ventricular myocardial tissue in the electron microscopy images. Rat hearts of each group were used to investigate the possible metabolic changes relevant to MIRI and diazoxide postconditioning. Results: The cardiac function indices in the Nor group were better than those in the other groups at the end point of reperfusion, and the HR, LVDP and +dp/dt_max of the Nor group at T2 were significantly higher than those of the other groups. Diazoxide postconditioning significantly improved cardiac function after ischaemic injury, and the HR, LVDP and +dp/dt_max of the DZ group at T2 were significantly higher than those of the I/R group, which could be abolished by 5-HD. The HR, LVDP and +dp/dt_max of the 5-HD + DZ group at T2 were significantly lower than those of the DZ group. The myocardial tissue in the Nor group was mostly intact, while it exhibited considerable damage in the I/R group. The ultrastructural integrity of the myocardium in the DZ group was higher than that in the I/R and 5-HD + DZ groups. The mitochondrial Flameng score in the Nor group was lower than that in the I/R, DZ and 5-HD + DZ groups. The mitochondrial Flameng score in the DZ group was lower than that in the I/R and 5-HD + DZ groups. Five metabolites, namely, L-glutamic acid, L-threonine, citric acid, succinate, and nicotinic acid, were suggested to be associated with the protective effects of diazoxide postconditioning on MIRI. Conclusion: Diazoxide postconditioning may improve MIRI via certain metabolic changes. This study provides resource data for future studies on metabolism relevant to diazoxide postconditioning and MIRI.